BACKGROUND: The efficient allocation of financial resources for malaria control and the optimal distribution of appropriate interventions require accurate information on the geographic distribution of malaria risk and of the human populations it affects. Low population densities in rural areas and high population densities in urban areas can influence malaria transmission substantially. Here, the Malaria Atlas Project (MAP) global database of Plasmodium falciparum parasite rate (PfPR) surveys, medical intelligence and contemporary population surfaces are utilized to explore these relationships and other issues involved in combining malaria risk maps with those of human population distribution in order to define populations at risk more accurately. METHODS: First, an existing population surface was examined to determine if it was sufficiently detailed to be used reliably as a mask to identify areas of very low and very high population density as malaria free regions. Second, the potential of
The influence of habitat quality and population density on occupancy dynamics may surpass that of traditional metrics of area and isolation, but often this is not considered explicitly in studies of spatially structured populations. In landscapes that are not easily characterized as binary habitat/non-habitat (e.g. variegated landscapes), this influence may be even more important and occur at both local and landscape levels. It follows that occupancy dynamics may be driven by disparate processes depending on how extinction or colonization relate to habitat quality and population density. We examined the relative influence of area, structural isolation, habitat quality, local population density, and neighborhood population density (i.e. population density in the landscape around a site) on the probability of extinction and colonization of snowshoe hare Lepus americanus across an expansive forest mosaic landscape (encompassing the northern third of Idaho). Habitat quality and population density ...
please write to my Twitter account @ebmpsykiatri if you find a country with worse ratio as I have not counted every country). Sweden: Corona deaths 14396. Population density 23/squarekilometer. Ratio: 626. Italy: Corona deaths 125501. Population density 201/sq.km. Ratio: 624. United Kingdom: Corona deaths 127724. Population density 267/sq.km Ratio: 473. Germany Corona deaths 88054 Population density 230/sq.km Ratio: 383. Hungary: Corona deaths 29581. Population density 106/squarekilometer. Ration: 273. Brazil Corona deaths 450206 Population density 26/sq.km Ration 173. Bosnien-Herzegovina: Corona deaths 9168. Population density 69/sq.km. Ratio: 134. Beligium Corona deaths 24853 Population density 369/sq.km. Ratio: 67. Finland Corona deaths 942 Population density 16/sq.km Ratio: 59. Norway Corona deaths 782 Population density 14/sq.km Ratio: 55. Denmark Corona deaths 2510 Population densitty 135/sq.km Ratio: 18. ...
A population is the number of living things that live together in the same place.[1] A citys population is the number of people living in that city. These people are called inhabitants or residents. The population includes all individuals that live in that certain area.The world population was estimated to have reached 7.5 billion in April 2017. Asia is the most populous continent, with its 4.3 billion inhabitants being 60% of the world population. Population density is the average number of people in a place. Urban areas such as big cities have a high population density. People there live close to each other. In areas with a low population density, people usually live far away from each other, such as in rural areas out in the countryside. Usually population refers to the number of humans in a certain area. The maximum population that can be supported in an area is called the carrying capacity. ...
Clearly, any UHI adjustments to past thermometer data will depend upon how the UHI effect is quantified at these very low population densities. Also, since I didnt mention it earlier, I should clarify that population density is just an accessible index that is presumed to be related to how much the environment around the thermometer site has been modified over time, by replacing vegetation with manmade structures. Population density is not expected to always be a good index of this modification - for instance, population densities at large airports can be expected to be low, but the surrounding runway surfaces and airplane traffic can be expected to cause considerable spurious warming, much more than would be expected for their population density.. UPDATE #2: Clarifications and answers to questions. After sifting through the 212 comments posted in the last 12 hours at Anthony Watts site, I thought I would answer those concerns that seemed most relevant. Many of the questions and objections ...
Oxitecs Director of Research, Luke Alphey, presented a summary of the results to date from their releases of OX513A strain males on GC during 2010. Males of this strain confer a lethal phenotype to their male and female progeny. (Since this is blog is a forum for me to express personal opinions, Id like to suggest that Oxitec consider naming their strains something more friendly that conveys some phenotype information!). First a bit of background is in order. If such technologies are ever implemented more widely, it is anticipated that male releases will be complemented with conventional control methods. The intent of this combination strategy is to pair conventional control measures that are effective at high population densities with sterile male methods which will be most efficient at low population densities.. According to information presented, population suppression of approximately 60% (my guess) was accomplished over an area of 15 hectares by releasing 5,000 males per week per hectare ...
The difficulty to locate mates and overcome predation can hamper species establishment and population maintenance. The effects of sparseness between individuals or the effect of predators on the probability of population growth can be difficult to measure experimentally. For testing hypotheses about population density and predation, we contend that habitat complexity can be simulated using insect mazes of varying mathematical difficulty. To demonstrate the concept, we investigated whether the use of 3D printed mazes of varying complexity could be used to increase spatial separation between sexes of Drosophila simulans, and whether the presence of a generalist predator hampered mate-finding. We then examined how increasing D. simulans population density might overcome the artificially created effects of increasing the distance between mates and having a predator present. As expected, there was an increase in time taken to find a mate and a lower incidence of mating as habitat complexity increased.
In our analysis, population extinctions today seem to be concentrated either where there are high human population densities, or where other human impacts, such as intensive agriculture, grazing, and hunting, have been severe. Larger mammals are often hunted to extinction or have their habitats preempted (13, 14). The mammal faunal sample from Southeast Asia shows one of the highest losses of species ranges and, thus, of mammal population extinctions: 57% of its quadrats have lost between 75 and 100% of their mammals. In Southeast Asia, human population density is extremely high (e.g., Indonesia, 115 persons per km2; China, 130 persons/km2; Pakistan, 190 persons/km2; India, 305 persons/km2). Similarly, in North America, the highest percentage losses are in the heavily populated eastern United States.. In Africa, the areas with the highest levels of mammal population extinction do not coincide as well with high human population densities (e.g., Nigeria has 135 persons/km2), even though there is a ...
Bangladesh is a developing country with a very high population density. The country has 160 million populations with a small area of only 147, 570 km . Currently, the population density is around 1200 persons per km 2 which is 50 times higher than the global average density of population, 3 times that of our neighbor India, 7 times that of China and 35 times that of the United States of America. The density in urban areas, particularly within Dhaka Megacity remains very high. The average density within the 1500 km 2 DMC region was over 10,000 persons per km 2 2 . in 2011 Census. However, within the urban built up area the density mostly varied from 20,000 to 75,000 persons per km . In some parts of the city, mostly at the older part, the density was found as high as over 200,000 inhabitants per km 2 2 . This thesis mainly deals with the population dynamics of Dhaka Megacity (DMC), more particularly the distribution and variation of population density and growth within the DMC region in recent ...
BACKGROUND: Pathogen transmission by mosquitos is known to be highly sensitive to mosquito bionomic parameters. Mosquito mark-release-recapture (MMRR) experiments are a standard method for estimating such parameters including dispersal, population size and density, survival, blood feeding frequency and blood meal host preferences. METHODS: We assembled a comprehensive database describing adult female MMRR experiments. Bibliographic searches were used to build a digital library of MMRR studies and selected data describing the reported outcomes were extracted. RESULTS: The resulting database contained 774 unique adult female MMRR experiments involving 58 vector mosquito species from the three main genera of importance to human health: Aedes, Anopheles and Culex. Crude examination of these data revealed patterns associated with geography as well as mosquito genus, consistent with bionomics varying by species-specific life history and ecological context. Recapture success varied considerably and was
This paper addresses the complex relationship between geography and macroeconomic growth. We investigate the ways in which geography may matter directly for growth, controlling for economic policies and institutions, as well as the effects of geography on policy choices and institutions. We find that location and climate have large effects on income levels and income growth, through their effects on transport costs, disease burdens, and agricultural productivity, among other channels. Furthermore, geography seems to be a factor in the choice of economic policy itself. When we identify geographical regions that are not conducive to modern economic growth, we find that many of these regions have high population density and rapid population increase. This is especially true of populations that are located far from the coast, and thus face large transport costs for international trade, as well as populations in tropical regions of high disease burden. Furthermore, much of the population increase in the next
Development Relevance: Population estimates are usually based on national population censuses. Estimates for the years before and after the census are interpolations or extrapolations based on demographic models. Errors and undercounting occur even in high-income countries; in developing countries errors may be substantial because of limits in the transport, communications, and other resources required conducting and analyzing a full census. Population density is a measure of the intensity of land-use, and can be calculated for a block, city, county, state, country, continent or the entire world. Considering that over half of the Earths land mass consists of areas inhospitable to human inhabitation, such as deserts and high mountains, and that population tends to cluster around seaports and fresh water sources, a simple number of population density by itself does not give any meaningful measurement of human population density. Several of the most densely populated territories in the world are ...
In contrast, the population in the outer boroughs rose continuously, except for a drop in 1945 caused by general war-time conditions. In 1933, the Tempelhof borough had an even higher average population density than the Kreuzberg borough. A growth in population of up to 300,000 people is expected by 2010. Up to 90 % of the residential space for these inhabitants is to be created by increasing the density of existing structures: putting additional floors on buildings; converting attic and roof spaces into residential units; building on vacant lots; increasing the density of more open construction styles; extending buildings constructed in the post-war period; etc.. Lower population density results not only from high proportions of green and open spaces and lesser degrees of development. Lower density can also be due to a large amount of small business, trade and service use, as well as public facilities, etc.. These property areas are included in calculations of population density. Detailed and ...
Methods that resulted in the most removals included volunteer-assisted shooting, ground shooting by staff, and aerial shooting, which was the most effort-effective method overall. Volunteer-assisted shooting accounted for 62% of all removals over the first 9 yr of the 13-yr effort, when mouflon were at high population density. The program had the benefit of involving the public in protecting NPS resources and facilitated a positive relationship with the public. However, volunteers preferentially targeted rams, which may distort the sex ratio of a population and result in increased population growth rates after density has been reduced in polygynous species such as mouflon (Stephens et al. 2008). Although ground shooting by staff, both with and without the use of dogs, also resulted in large numbers of removals, these methods became less efficient after densities had been reduced.. The effort required to remove the last remaining mouflon increased nearly 15-fold after the fenced unit was enclosed ...
Many common bacterial pathogens use chemical signals to coordinate group behaviors. In the canonical quorum sensing (QS) system of V. fischeri, a synthase, LuxI, produces an N-acyl homoserine lactone (AHL) that is recognized by a receptor, LuxR, at high signal density. LuxR is a transcription factor that regulates bioluminescence and other group behaviors at high population density in an AHL dependent manner. SdiA is a LuxR homolog found in Escherichia coli and Salmonella enterica serovar typhimurium. SdiA does not have a corresponding synthase, however, and these species do not produce AHL signals. SdiA does not respond to population density, but rather has been shown to respond to AHLs produced by other bacterial species in its environment. SdiA regulates many aspects of pathogenesis including directing the location of the infection, survival in the mammalian digestive system, and the production of virulence factors. Accordingly, modulation of SdiA activity might be a useful anti-virulence ...
We have found that cell-cell signaling is used to regulate horizontal transfer of the integrative and conjugative element ICEBs1, a conjugative transposon found in the B. subtilis genome. These types of elements are widespread in the microbial world and contribute to horizontal gene transfer, evolution, virulence, and the spread of antibiotic resistance. ICEBs1 is regulated by population density and cell-cell signaling in two ways. 1) At high population density, in the presence of potential mating partners, the element is stimulated to excise from the chromosome and can then transfer to potential recipients. 2) However, if the potential recipients already contain a copy of the element, then excision of the element is inhibited and there is little or no transfer to the potential recipients that already contain the element. We found that the secreted pentapeptide, a product of phrI, that regulates this recognition of self is encoded in the element. In the absence of this peptide, as cells grow ...
Background Pathogen transmission by mosquitos is known to be highly sensitive to mosquito bionomic parameters. Mosquito mark-release-recapture (MMRR) experiments are a standard method for estimating...
If a river or lake is in good condition, we usually find that there is much more nitrogen than phosphorus, and if the growth of algae and aquatic plants is limited it is usually due to a lack of phosphorous, explains Peñuelas. However, the constant dumping of detergents, pesticides, fertilizers, and urban and industrial wastewater in many river basins throughout the world adds huge quantities of phosphorous, which is accumulating much more quickly than nitrogen or other elements such as potassium. With this, the special role of phosphorus has changed from a desirable nutrient to a contaminant in urban areas with high population density and areas with intensive agriculture.. Under natural conditions, algae tissues contain seven times more nitrogen than phosphorous, and in terrestrial plants this proportion can be as high as 15 times greater. Most soils and rocks contain low amounts of phosphorous, an element which has very low solubility in water. For this reason, freshwater species have ...
Ammonia emissions have been increasing as a result of agricultural activities in Canada. Since 1981, emissions from fertilizer have more than doubled (from 63,000 kilotonnes of nitrogen in 1981, up to 130,000 kilotonnes of nitrogen in 2011). Conversely, livestock-related emissions have been decreasing, particularly since 2006. These trends reflect Canadas national trend towards more land under annual crops, and less area given to livestock and associated forage production.. Use the interactive map below to zoom in and explore different regions. Note that some of the highest emissions per hectare (relating to both livestock and fertilizer emissions) occur in the Mixedwood Plains region of southern Ontario and Quebec. The high population density in these regions increases the potential for human health implications. Other areas of relatively high emissions include the Aspen Parkland, Moist Mixed Grassland and Lake Manitoba Plain regions of the Prairies. The Lower Fraser Valley region of British ...
If any of us has seen the places in the developing world that Mike Davis catalogues remorselessly in Planet of Slums, it was probably from an aeroplane. That doesnt always mean 35,000 feet, for as Davis points out, poorer people tend to colonise the marginal land of cities where air terminals were once built at a comfortable distance from prosperous centres of medium or high population density. Prosperity in the newer, informal urban environment - in Caracas or Lagos, say - is reckoned by incomparably different standards. Davis, the urban historian who also excels at apocalyptic geography, sketches the various ways in which its inhabitants can make ends meet. He also lists ways, based mostly on exploitation, in which they might even profit. In the end, the burgeoning pauper conurbations are as wretched as they look from the cabin window.. Daviss books are great evidential engines. Planet of Slums howls with figures. Copious examples drawn from around the globe are stacked up to illustrate a ...
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Each year I vow to publish this analysis in a more timely manner and, it seems, that each year it gets tougher to do. But this is a massive undertaking, so I hope youll cut me some slack. First, a little about my methodology is in order. For each nation, I tallied the imports from…
One of the most important threats to global public health, especially in developing countries is parasitic infections. These infections are very common in children and young people especially those who kept in kindergarten and primary schools. Because of the high population density and sometimes by the lack of adequate hygiene, these places are prone to parasitic infections. Infestation causes by ectoparasites like pediculosis, water-borne protozoan infections like giardiasis and the last but not less important, helminth infection like as Oxyuris are a permanent threat for children in this places.
As a leading global city with a high population density, Singapore is vulnerable to the introduction of biological threats. Initiating an early emergency response to such threats calls for t... Read more ...
It was a hazy and hot day as I sat in my grade school New York City classroom. Suddenly, everyones attention was drawn to my classmates wheezing and labored breathing. Àngel was one of the biggest kids in our class, but he was clearly in distress and the memory of his pain is vivid. I now understand that my friend was having an asthma attack. Thankfully, our teacher knew precisely what to do and she had his inhaler inside her desk and ready.. Our Manhattan public school was located adjacent to a major highway known as the FDR Drive, which snakes up Manhattans eastside near the Williamsburg Bridge. The combination of high population density, cars, trucks and industrial activity was a recipe for dismal air quality.. Àngel and many of my inner-city cohort shared a Puerto Rican ancestry. To this day, I remain puzzled by the disproportionately high asthma rate among Latinos. Latinos are 30 percent more likely to go to the hospital for asthma, as compared to non-Hispanic Whites. For reasons that ...
US census maps - demographics ECPM Département de langues Map United States Population Density , Direct Maps File:US population map.png Wikimedia Commons Map United States Population Density , Direct Maps What is a map? Map skills and higher order thinking The Functional Art: An Introduction to Information Graphics and Map of NFL teams overlaying a US population density map : nfl US census maps - demographics ECPM Département de langues US Population Density Map in 3D , ...
The Gridded Population of the World, Version 4 (GPWv4): Population Density Adjusted to Match 2015 Revision of UN WPP Country Totals, Revision 11 consists of estimates of human population density (number of persons per square kilometer) based on counts consistent with national censuses and population registers with respect to relative spatial distribution, but adjusted to match the 2015 Revision of the United Nations World Population Prospects (UN WPP) country totals, for the years 2000, 2005, 2011, 2015, and 2020. A proportional allocation gridding algorithm, utilizing approximately 13.5 million national and sub-national administrative units, was used to assign UN WPP-adjusted population counts to 30 arc-second grid cells. The density rasters were created by dividing the UN WPP-adjusted population count raster for a given target year by the land area raster. The data files were produced as global rasters at 30 arc-second (~1 km at the equator) resolution. To enable faster global processing, and ...
Knowledge of the effective size of populations, Ne, and the ratio of effective population size to the size of the mature population Ne/N, provide important information of the genetic diversity and fitness of populations. However, the theoretical parameter Ne was originally defined for populations with discrete generations, and most models that aim to estimate Ne for populations with overlapping generations relies on a set of simplifying, often unrealistic assumptions. Whenever these assumptions are violated, the predicted size of Ne may be highly biased and this may potentially lead to erroneous decisions in conservation and management. Hence, there is a need for more knowledge about how different processes occurring in natural populations affect the effective size of populations, and the Ne/N ratio. The main goal of this thesis was to relax one of the most unrealistic assumptions underlying many models: constant population size, or at the very best that fluctuations are only caused by density ...
TY - JOUR. T1 - Population density methods for large-scale modelling of neuronal networks with realistic synaptic kinetics. T2 - Cutting the dimension down to size. AU - Haskell, Evan. AU - Nykamp, Duane Q.. AU - Tranchina, Daniel. PY - 2001/5. Y1 - 2001/5. N2 - Population density methods provide promising time-saving alternatives to direct Monte Carlo simulations of neuronal network activity, in which one tracks the state of thousands of individual neurons and synapses. A population density method has been found to be roughly a hundred times faster than direct simulation for various test networks of integrate-and-fire model neurons with instantaneous excitatory and inhibitory post-synaptic conductances. In this method, neurons are grouped into large populations of similar neurons. For each population, one calculates the evolution of a probability density function (PDF) which describes the distribution of neurons over state space. The population firing rate is then given by the total flux of ...
THE standard neutral coalescent model (Kingman 1982a,c; Hudson 1983; Tajima 1983) assumes a panmictic species with a constant, large, effective population size over time within which no selective differences exist. While this model is often applied in the analysis of genetic data, its assumptions are probably inappropriate for most organisms. That is, many species are subdivided and/or have changed in size over time and/or are subject to natural selection. The study of genealogical processes in populations subject to these forces has been a major part of the recent effort in population genetics. The key parameter of the coalescent is the effective population size, Ne, because this is what determines the time scale of the process. It is important to note that some biologically interesting characteristics of species are manifest only through this effective size. These include the distribution of offspring number among individuals in the population and the details of the age structure of the ...
An increase in offspring-number variation leads to more variable population dynamics, which on one hand lets successful populations escape even faster from the range of small population sizes than under the Poisson model. On the other hand, a large variation also prevents successful Allee-effect populations from spending much time near or above the critical population size because those that do still have a high risk of going extinct even at such high population sizes. Therefore, an increase in variability reinforces the speed-up effect but mitigates the slow-down effect and thus increases the range of founder population sizes for which the genetic consequences of the Allee effect are positive (see Figure 2 and Figure 4). In that sense, variation in family sizes plays a similar role as variation in founder population size and in the number of introduction events (see Figure 4), two factors that were examined in Wittmann et al. (2014) and, in the case of founder population size, also by Kramer ...
NeEstimator v2 is a completely revised and updated implementation of software that produces estimates of contemporary effective population size, using several different methods and a single input file. NeEstimator v2 includes three single-sample estimators (updated versions of the linkage disequilibrium and heterozygote-excess methods, and a new method based on molecular coancestry), as well as the two-sample (moment-based temporal) method. New features include the following: (i) an improved method for accounting for missing data; (ii) options for screening out rare alleles; (iii) confidence intervals for all methods; (iv) the ability to analyse data sets with large numbers of genetic markers (10000 or more); (v) options for batch processing large numbers of different data sets, which will facilitate cross-method comparisons using simulated data; and (vi) correction for temporal estimates when individuals sampled are not removed from the population (Plan I sampling). The user is given ...
From a microbes point of view the human body is a vast array of surfaces some internal, others external that are continuously colonized by endemic and exotic microbes beginning from the time of our birth and continuing throughout life up until and even beyond the point of death. The surfaces on which these organisms grow and are constantly being sloughed off as new tissues form beneath existing ones resulting in the loss of established biofilms but providing new and uncolonized, or at least less colonized, cell surfaces on which new biofilm communities can be come established. These interconnected ecosystems vary from highly abraded, exceptionally dry habitats on the surface of the skin (e.g. the elbow) to constantly moist, highly nutritious membranous surfaces (the conjunctiva of the eye), from niches of low population density and a pH of 3 (stomach) to habitats with a hydrogen ion concentration a million fold lower and a population density of 1011 cells /gram (gut). Then, within the same ...
Downloadable (with restrictions)! This paper investigates nonparametric estimation of density on [0, 1]. The kernel estimator of density on [0, 1] has been found to be sensitive to both bandwidth and kernel. This paper proposes a unified Bayesian framework for choosing both the bandwidth and kernel function. In a simulation study, the Bayesian bandwidth estimator performed better than others, and kernel estimators were sensitive to the choice of the kernel and the shapes of the population densities on [0, 1]. The simulation and empirical results demonstrate that the methods proposed in this paper can improve the way the probability densities on [0, 1] are presently estimated.
Some forms of positive density-dependence can favor species coexistence even if competitive species benefit the most from positive density-dependence.
Learning Goals: Use a quadrat to sample an area of the school lawn and calculate the population density of 4 common weeds.. Key Concepts: density, carrying capacity, biodiversity, quadrat sampling. Download a copy of the Population Density lab Indoor Quadrat Alternate Assignment:. http://www.patriotspointsciencespotlight.com/images-and-data-submission.html. Lab - Introduction to Quadrats. Quadrats - the Point-Intercept Method. ...
As predicted, invasion-front toads were more likely to approach conspecifics and spent more time with them than did toads from long-colonized populations. We also found a sex effect; males were more likely to approach conspecifics and spent more time with them than did females. Because our stimulus toads were female, that sex bias might reflect sexual rather than social attraction. However, the greater sociality of male than female toads was seen in both long-colonized and range-edge populations, suggesting that the effect of invasion history on social attraction was not due to differences in sexual selection among populations. Below, we consider possible explanations for the divergence in social attraction between long-colonized and invasion-front populations.. First, the costs and benefits of social attraction may differ at high versus low population densities, which in turn differ predictably across the invasion range. For example, low densities at the invasion front may reduce ecological ...
The conditions for enterprise differ in some respects between companies in urban and rural areas. The geographical situation in rural areas entails large distances to customer and suppliers. A limited labour market and other functions of significance mean that travel and transports are more expensive and take more time. The possibility of recruiting personnel with the right expertise is affected by a limited local labour market. Long distances make work commutes difficult. Properties and facilities in rural areas often have low second-hand value which makes it difficult for companies to provide collateral for bank loans. Low population density and climate need not necessarily always be competitive disadvantages. For enterprises where the business has a special need for space, natural resources, climate, etc. these characteristics are often an advantage and in some cases a prerequisite. Agriculture, forestry, mineral extraction, some kinds of tourism, testing activities, etc. are examples of ...
Establish transportation services for areas with low population densities using publicly funded buses and vans on a set schedule, dial-a-ride transit, volunteer ridesharing, etc. ...
Figure 1 of Nielsen et al., paper shows multiple (up to 21) synonymous and non-synonymous substitutions in thousands of chimp proteins compared to the related human proteins. In the second paper Behe & Snoke conclude that in order to generate a new function that requires mutations of two amino acids, like forming a disulfide bridge, 108 generations are needed with a population size of at least 109. In the third paper, Lynch countered that much smaller populations could reach this goal in less time. Now, if we take the human population size from the above two studies (Ne about 104) for the population size in Figure 3 of the Lynch article, we can see that it would take 108 generations for the arrival of a new function, even if the two changed amino acid were any 2 of 50 (with a high s = 0.01). For humans, 108 generations mean 2 Billion years: an impossibly long period. Needless to say, a new function requiring 3, 4 … up to 21 amino acid changes would take much longer than 108 generations. And ...
Figure 1 of Nielsen et al., paper shows multiple (up to 21) synonymous and non-synonymous substitutions in thousands of chimp proteins compared to the related human proteins. In the second paper Behe & Snoke conclude that in order to generate a new function that requires mutations of two amino acids, like forming a disulfide bridge, 108 generations are needed with a population size of at least 109. In the third paper, Lynch countered that much smaller populations could reach this goal in less time. Now, if we take the human population size from the above two studies (Ne about 104) for the population size in Figure 3 of the Lynch article, we can see that it would take 108 generations for the arrival of a new function, even if the two changed amino acid were any 2 of 50 (with a high s = 0.01). For humans, 108 generations mean 2 Billion years: an impossibly long period. Needless to say, a new function requiring 3, 4 … up to 21 amino acid changes would take much longer than 108 generations. And ...
Population Density Defined as total population size per unit of area. Population densities depend on: Interactions within the environment Quality of habitat
The twin concepts of zooprophylaxis and the dilution effect originated with vector-borne diseases (malaria), were driven forward by studies on Lyme borreliosis and have now developed into the mantra biodiversity protects against disease. The basic idea is that by diluting the assemblage of transmi …
Background Increasing evidence shows that the cancer microenvironment affects both tumorigenesis and the response of cancer to drug treatment. Therefore in vitro models that selectively reflect characteristics of the in vivo environment are greatly needed. Current methods allow us to screen the effect of extrinsic parameters such as matrix composition and to model the complex and three-dimensional (3D) cancer environment. However, 3D models that reflect characteristics of the in vivo environment are typically too complex and do not allow the separation of discrete extrinsic parameters. Methodology/Principal Findings In this study we used a poly(ethylene glycol) (PEG) hydrogel-based microwell array to model breast cancer cell behavior in multilayer cell clusters that allows a rigorous control of the environment. The innovative array fabrication enables different matrix proteins to be integrated into the bottom surface of microwells. Thereby, extrinsic parameters including dimensionality, type of matrix
In summary, the spectrum of protein-coding variation is considerably different today compared to what existed as recently as 200 to 400 generations ago. Of the putatively deleterious protein-coding SNVs, 86.4% arose in the last 5,000 to 10,000 years, and they are enriched for mutations of large effect as selection has not had sufficient time to purge them from the population. Thus, it seems likely that rare variants have an important role in heritable phenotypic variation, disease susceptibility and adverse drug responses. In principle, our results provide a framework for developing new methods to prioritize potential disease-causing variants in gene-mapping studies. More generally, the recent dramatic increase in human population size, resulting in a deluge of rare functionally important variation, has important implications for understanding and predicting current and future patterns of human disease and evolution. For example, the increased mutational capacity of recent human populations has ...
When Who What Sept 15 Guy A. Inferring human population size and separation history from multiple genome sequences. Nature Gen. Schiffels and Durbin, 2014. Sept 22 Joe Common genetic variants associated with cognitive performance identified using the proxy-phenotype method. PNAS 2014 Sept 29 Sonal Comparative population genomics in animals uncovers the determinants of genetic diversity. Nature. Romiguier et…
Using a relatively simple density-dependent population model and assuming constant young of year survival with no immigration/emigration, reductions in cumulative fecundity have been predicted to yield declines in population size over time (Miller and Ankley 2004). Under real-world environmental conditions, outcomes may vary depending on how well conditions conform with model assumptions. Nonetheless, cumulative fecundity can be considered one vital rate that contributes to overall population trajectories (Kramer et al. 2011).. ...
Access Frankston Heights population density figures plus suburb map, boundaries, population distribution, demographics, in an accurate, easy to use website.
Access Reynella population density figures plus suburb map, boundaries, population distribution, demographics, in an accurate, easy to use website.
Aim: The recent recovery of large carnivores in Europe has been explained as resulting from a decrease in human persecution driven by widespread rural land abandonment, paralleled by forest cover increase and the consequent increase in availability of shelter and prey. We investigated whether land cover and human population density changes are related to the relative probability of occurrence of three European large carnivores: the grey wolf (Canis lupus), the Eurasian lynx (Lynx lynx) and the brown bear (Ursus arctos).Location: Europe, west of 64 degrees longitude.Methods: We fitted multi-temporal species distribution models using ,50,000 occurrence points with time series of land cover, landscape configuration, protected areas, hunting regulations and human population density covering a 24-year period (1992-2015). Within the temporal window considered, we then predicted changes in habitat suitability for large carnivores throughout Europe.Results: Between 1992 and 2015, the habitat suitability ...
We used a simple discrete-time population model to investigate how temporally structured density-dependence influences a populations response to loss due to harvesting. We assumed that reproduction is a relative discrete event in time, followed by density-dependent mortality and then harvesting, or followed by harvesting and then density-dependent mortality. Such an ordering of events in time may have profound influences on the dynamics of the population. The extra mortality due to harvesting may either be additive or compensatory depending on the strength of the density-dependence and the ordering of events. Population stability is also strongly affected by the temporal structure of density-dependence. Moreover, the yield and the (unconstrained) optimal harvest rate will vary depending on when harvesting occurs in the annual cycle. We argue that a correct identification of the temporal structure of density-dependence may be of great importance for understanding population dynamics in general ...
Objective. To assess whether higher mortality rates among individuals in motor vehicle crashes in areas with low population density depend on injury type and severity or are related to the performance of emergency medical services (EMS).. Methods Prehospital and hospital deaths were studied in a population-based cohort of 41 243 motor vehicle crashes that occurred in Sweden between 1998 and 2004. The final multivariable analysis was restricted to 6884 individuals in motor vehicle crashes, to minimise the effects of confounding factors.. Results Crude mortality rates following motor vehicle crashes were inversely related to regional population density. In regions with low population density, the unadjusted rate ratio for prehospital death was 2.2 (95% CI 1.9 to 2.5) and for hospital death 1.5 (95% CI 1.1 to 1.9), compared with a high-density population. However, after controlling for regional differences in age, gender and the type/severity of injuries among 6884 individuals in motor vehicle ...
Data & statistics on Population Poverty Rates by Sex of Household Head and Residence: Poverty Indices according to Region of Residence, Gender, Sector of Employment, Education Level, and Mode of Living of Head of Household (1990, 1996), Disaggregates rural poverty rates across Malawis three regions. Poverty rates in the rural south have historically been highest, while those in the north are lowest. The relative disadvantage of southerners relates in part to land constraints in the face of high population density: the 2008 Population Census puts the population density in the south at 184 persons per square kilometer compared to only ..., Descriptive statistics of variables Variable District-level Access to services Distance from Accra Distance from regional capital Agro-ecological zone Forest Coastal Ethnic fractionalization Share of rural population Population density (log) Literacy rate Headcount ratio Poverty gap Per capita total expenditures (log) Per capita capital expenditures (log) Internal
Development Relevance: Population estimates are usually based on national population censuses. Estimates for the years before and after the census are interpolations or extrapolations based on demographic models. Errors and undercounting occur even in high-income countries; in developing countries errors may be substantial because of limits in the transport, communications, and other resources required conducting and analyzing a full census. Population density is a measure of the intensity of land-use, and can be calculated for a block, city, county, state, country, continent or the entire world. Considering that over half of the Earths land mass consists of areas inhospitable to human inhabitation, such as deserts and high mountains, and that population tends to cluster around seaports and fresh water sources, a simple number of population density by itself does not give any meaningful measurement of human population density. Several of the most densely populated territories in the world are ...
A cohort effect is a phenomenon where cohorts of a population differ from each other in some key attribute(s), such body mass. Birth mass, birth dates, rate of growth of juveniles, survival over the first winter, age of first reproduction, and adult survival rates are often related to the influence of the time of birth, which itself is a product of the environmental conditions cohorts face at birth as well as the nutritional condition of their mothers (itself a reflection of environmental conditions faced at or prior to birth). Environmental conditions that can influence birth and early growth attributes include droughts, abnormally high rainfall, late snowfall, and high population density. These and other factors influence birth attributes and early development of juveniles, and these early effects may persist and affect phenotypic quality throughout the lifetime of the cohort. Because many of these cohort effects - body size, body mass, etc. - are tied to survival and reproductive fitness, ...
We analysed the data from the control group in a typhoid vaccine trial in Karachi to assess the differences in individual-, household- and cluster-level characteristics for developing typhoid fever. The annual incidence of typhoid in children aged 2-16 years in the control arm of the vaccine trial was 151/100 000 population. After adjustment, the risk of typhoid was lower with increasing age [risk ratio (RR) 0·89, 95% confidence interval (CI) 0·83-0·95], was higher with an increase in population density (RR 1·13, 95% CI 1·05-1·21) and was lower in the households using a safe drinking-water source (RR 0·63, 95% CI 0·41-0·99). Typhoid fever affects younger children living in areas of high population density and lack of access to safe water in Pakistan. A combination of environmental and biological interventions is required to prevent the continued epidemiological and economic impact of typhoid fever in high-risk areas of Pakistan.
Interpretive Summary: Social insects defend themselves against parasites and pathogens using behaviour and physiological defenses. This study explores immune defense found in honey bees, two bumble bee species and a solitary pollinator, the alfalfa leafcutting bee. All of these groups show a similar set of immune genes, stressing the importance of immunity across the bees, and indicating additional targets for selection of robust honey bees for agriculture. Technical Abstract: Sociality has many rewards, but it can also be dangerous, as high population density and low genetic diversity, common in many social insects, is ideal for parasite transmission. Social insects may therefore be expected to have evolved a specialised immune arsenal to guard against this threat. Surprisingly, the honeybee genome, which was the first social insect genome sequenced, revealed a dramatic reduction in the number of canonical immune-related genes relative to the genomes of solitary insects. Social protection from ...
The staggering 65 per cent of Japans- a high population density country- terrestrial area under forest cover owes it largely to the forced land reforms in the post world war two period, although the original intention of the occupying Americans was to wither the feudal support base of the king. Nicaraguas land reforms initiated by President Daniel Ortega in the 80s -shelved later with the change in government- were followed by a reduction in forest encroachments. Cubas small holdings were central to shaping its success in expanding agrobiodiversity and reducing the use of agrochemicals in the post Soviet period. On the other hand, apartheids appropriation of farmlands created the twin crises of accelerating rural poverty and biodiversity degradation in southern Africa. The land reform move initiated by the Soviet sponsored government in Afghanistan was at the core of the feudal resistance which was strategically utilized by the US to generate self perpetuating violence of formidable ...
This study aims to assess the determinants of the labor market in the Greater Jakarta Area (Jabodetabek) with a population of 27.9 million (2010 census) and growth rate of 3.6 percent per annum over the period 2000-2010. With a total area of 4,384 square kilometers (1,693 sq mi), the city has a very high population density of 14,464 people per square kilometer (37,460/ sq mi), while the metro area has a density of 4,383 people/sq km (11,353/sq mi). The paper employs the survival regression analysis by incorporating attributes of commuter, namely gender, age, distance, travel time, wages, stress, education level, double income households and home ownership. The area consists of Jakarta as the receiving labor market and eight municipalities and regencies as labor suppliers. The study utilizes a cross-section data from a commuter survey with more than 4,000 respondents participated using different modes of land transport. The results reveal that some determinants have influenced commuters ...
South Korea - Plant and animal life: The long, hot, humid summer is favourable for the development of extensive and varied vegetation. Some 4,500 plant species are known. Forests once covered about two-thirds of the total land area, but, because of fuel needs during the long, cold winter and the countrys high population density, the original forest has almost disappeared. Except for evergreen broad-leaved forests in the narrow subtropical belt along the southern coast and on Cheju Island, most areas contain deciduous broad-leaved and coniferous trees. Typical evergreen broad-leaved species include camellias and camphor trees, while deciduous forests include oaks, maples, alders, zelkovas, and birches. Species of
March 2007. Abstract. Malawi, like other countries in Africa, has a new land policy designed to clarify and formalise customary tenure. The country is poor with a high population density, highly dependent on agriculture, and the research sites are matrilineal-matrilocal, and near urban centres. But the case raises issues relevant to land tenure reform elsewhere: the role of traditional authorities or chiefs vis-à-vis the state and community; variability in types of customary tenure; and deepening inequality within rural populations. Even before it is implemented, the pending land policy in Malawi is intensifying competition over land. We discuss this and the increase in rentals and sales; the effects of public debates about the new land policy; a new discourse about original settlers and strangers; and political manoeuvring by chiefs.. Keywords: land tenure, land reform, land rentals and sales, Malawi. JEL subject codes: Z1. ...
Chugoku Mountains,middle country,water animal,industrial pollution,Shimane,Inland Sea,Tottori,port cities,Okayama,high population density,mild climate,Yamaguchi,vineyards,aquaculture,fishing,zone,activities,center
In most countries in the Asian region, ruminant animals, particularly cattle and buffalo, have an important economic role in village farming systems to provide milk, draught power, manure, meat and hides. Milk is an important constituent in the diet of large populations in countries like India and Pakistan. Its value is being increasingly recognized in other countries in the region too. Increasing incorporation of milk in the diets of the people in the region focuses attention on the value of milk not only as a source of nourishment for the rural small scale producer but also as a source of supplementary income for them. High population densities in the region make it essential that the production systems should ensure the optimum utilization of scarce land resources, whether it be for production of food or other crops. In this context, the vast capacity of cattle and buffalo to convert crop residues and by-products into economically useful products has to be used to the best advantage of the small
Following the increased attention income differences/inequality has gained within the area of economic geography and among policy-planning; this study seeks to explore and analyze the factors affecting income differences in the regions of Ghana. From the use of regional (10 regions) panel data for 1960, 1970, 1984 and 2000; the results show a direct link between socio-demographic factors and regional income differences/inequality and also the impact of ethnic and religious composition on regional income differences. It was identified that ethnicity and religious compositions have different impacts on regional income differences. Christians have positive effect on regional income due to their fairly representation in almost all the regions likewise the Akans, but have negative effect on regional income. And also high population density in a region reduces the mean regional income, similarly high concentration of population aged 60years and over reduces the regional income. Evidence from the ...
How do insurance companies determine your insurance premiums? In addition to your driving record, there are other factors taken into consideration when doing the math to figure out what your insurance premium will be.. Five Factors Used To Determine Car Insurance Premiums:. 1. What type of vehicle do you own? The model, year, and value of your car can have an impact on your insurance premium. Cars that are more expensive to repair will be more expensive to insure.. 2. What is your age, sex and marital status? Statistics show that older drivers, female drivers and married drivers tend to have better driving records. Because of this, these drivers usually have lower premiums.. 3. Is your vehicle used for work or pleasure? Using your vehicle for work will probably increase your premium.. 4. What is your prior insurance coverage? If you are a new driver or if you do not have insurance coverage, you will incur higher rates.. 5. Where do you live? States with high population density tend to have more ...
To defend ourselves we have only general antiviral (that must be administered to adolescents, older adults, children, doctors, nurses, pharmacists, police, firemen, government authorities and special security) and the known epidemiological methods (masks :spreads by coughing and constant sneezing, washing hands, avoiding greet with kisses, avoiding places of high population density: buses, metros, auditoriums, schools, churches, checking travelers at air terminals, isolation of patients, etc). The last allows Keiji Fukuda (WHO), to ensure that there are now more stocks of antiviral drugs to prevent infection by the virus. If someone developed an intentionally biological warfare not need imagine much, just keep a visual inventory of what is currently deployed in the media: fast replication of new viral strains (due to absence of natural immunity), increasing numbers of people affected, weak international sanitary barriers (uncontrollable intrusion of Mexican drug traffickers, with aircraft or ...
With novel developments in sequencing technologies, time-sampled data are becoming more available and accessible. Naturally, there have been efforts in parallel to infer population genetic parameters from these data sets. Here, we compare and analyse four recent approaches based on the Wright-Fisher model for inferring selection coefficients (s) given effective population size (N-e), with simulated temporal data sets. Furthermore, we demonstrate the advantage of a recently proposed approximate Bayesian computation (ABC)-based method that is able to correctly infer genomewide average N-e from time-serial data, which is then set as a prior for inferring per-site selection coefficients accurately and precisely. We implement this ABC method in a new software and apply it to a classical time-serial data set of the medionigra genotype in the moth Panaxia dominula. We show that a recessive lethal model is the best explanation for the observed variation in allele frequency by implementing an estimator ...
Like predation and competition, mutualism is now recognized as a consumer resource (C-R) interaction, including, in particular, bi-directional (e.g., coral, plant- mycorrhizae) and uni-directional (e.g., ant-plant defense, plant-pollinator) C-R mutualisms. Here, we develop general theory for the density-dependent population dynamics of mutualism based on the C-R mechanism of interspecific interaction. To test the influence of C-R interactions on the dynamics and stability of bi- and uni-directional C-R mutualisms, we developed simple models that link consumer functional response of one mutualistic species with the resources supplied by another. Phase-plane analyses show that the ecological dynamics of C-R mutualisms are stable in general. Most transient behavior leads to an equilibrium of mutualistic coexistence, at which both species densities are greater than in the absence of interactions. However, due to the basic nature of C-R interactions, certain density-dependent conditions can lead to C-R
article{9837a013-2002-40ce-93f0-0bf266da9173, abstract = {Within the paradigm of population dynamics a central task is to identify environmental factors affecting population change and to estimate the strength of these effects. We here investigate the impact of observation errors in measurements of population densities on estimates of environmental effects. Adding observation errors may change the autocorrelation of a population time series with potential consequences for estimates of effects of autocorrelated environmental covariates. Using Monte Carlo simulations, we compare the performance of maximum likelihood estimates from three stochastic versions of the Gompertz model (log-linear first order autoregressive model), assuming 1) process error only, 2) observation error only, and 3) both process and observation error (the linear state-space model on log-scale). We also simulated population dynamics using the Ricker model, and evaluated the corresponding maximum likelihood estimates for ...
Dear colleagues Thanks a lot for making the paper by Smith (1935) accessible to me, which was in turn requested by a good number of ANNELIDA users. Once I have been able to pin down the concept of density dependence (in fact sensu density-dependent mortality factors), I am now tracking the original definition of the concept of regulation in the context of population dynamics where it refers to population size self-adjustment, where density dependence might [I am not sure yet] represent the otherwise called return tendency, i.e. mortality rates increasing and birth rates decreasing as population size increases. This is much harder a task since regulation is quite a rather general, easy-to-use term. The theory of population regulation seems to be attributed to Alexander John Nicholson (see Turchin 2003, p. 5, and others), and in fact the origin of the (still debated, see White 2008) regulation versus limitation controversy is most commonly associated with the exchange of ideas between Nicholson ...
Now the rate of genetic drift and the efficiency of selection in a population is governed by the effective population size. The effective size of a population (Ne) is often much smaller than the census size of the population, as it is affected by the variance in reproductive success between individuals. The effective population size is very hard to predict as it depends on many demographic factors. Ne can be estimated from patterns of genetic diversity, and the long-term estimated effective population size of humans is ~10,000 (similar to many great apes), reflecting the strong effect of genetic drift in the evolutionary history of humans. Now human populations have recently expanded dramatically in size. All else being equal human effective population sizes will have increased as well, but there is no good way of guessing how much they have increased by. For example rapidly fluctuating population sizes, result in a smaller Ne. If the fluctuations are sufficiently rapid, Ne can be approximated ...
Traditional sociological insights assume that cities are characterized by lower levels of voluntary engagement as it is expected that community size and population density are negatively associated with network and mobilization opportunities. Others, however, argue that cities allow for the formation of different networks that are no longer based on ascribed personal characteristics. We analyze voluntary association membership in Belgium, based on the „Social Cohesion Indicators in Flanders‟ dataset (n=2,080 respondents, sampled in 40 communities). The analysis shows that neither population density nor community size have an effect on scope or intensity of participation in voluntary associations. Only two forms of associations are negatively related to population density. Our results therefore do not support the hypothesis of a rural-urban divide in participation in voluntary associations. We speculate how future research could take into account different sorts of voluntary associations when ...
The Crau Plain grasshopper, Prionotropis rhodanica Uvarov, 1923 (Orthoptera: Pamphagidae: Thrinchinae), is a rare grasshopper species endemic to the Crau Plain, a steppic habitat in France with unique floristic and faunistic communities. During recent decades, the area covered by these steppic grasslands has been highly reduced and fragmented due to the development of irrigation-based agriculture, roads, as well as industrial and military complexes. The restricted distribution, low population density and poor dispersal ability of P. rhodanica, combined with the destruction of its habitat, has led to the classification of this species as critically endangered in the IUCN Red List of Threatened Species. Decreases in habitat quality due to intensive grazing in the remnant grassland patches constitute an additional threat for P. rhodanica that can impact population dynamics at a relatively small-scale. In this work, we focused on a small area of about 3 km2 occupied by one of the largest subpopulations
TY - JOUR. T1 - Quantifying invasion risk: the relationship between establishment probability and founding population size. AU - DUNCAN, Richard. AU - Blackburn, Tim M.. AU - Rossinelli, Silvia. AU - Bacher, Sven. PY - 2014. Y1 - 2014. N2 - Invasive species usually start out as small colonizing populations that are prone to extinction through demographic stochasticity and Allee effects, leading to a positive relationship between establishment probability and founding population size. However, establishment success also depends on the environment to which species are introduced: for a given species, some locations will be more favourable for establishment than others. We present equations for modelling the expected relationship between establishment probability and founding population size when demographic stochasticity, Allee effects and, for the first time, environmental heterogeneity are operating. We show that heterogeneity in environmental conditions can change the shape of the relationship ...
In this study, the authors extend their previous research by using a multi-patch model to analyze Allee effects within the context of migration between patches. We investigate the combined effect of a fatal disease, Allee effect and migration on different groups of the same species, Yakubu says. In their conclusions, the host population is seen to become extinct whenever the initial host population density on each patch is lower than the smallest Allee threshold. When the initial host population has a high Allee threshold, the population persists on each patch if the disease transmission rates are small and the growth rate is large. Even in the case of high Allee thresholds, the host population goes extinct if the disease transmission rate is high, and growth rate and disease threshold are small. The presence of a strong Allee effect adds the possibility of population extinction even as the disease disappears. ...
TY - JOUR. T1 - Apparent breeding success drives long-term population dynamics of a migratory swan. AU - Nuijten, Rascha. AU - Vriend, S.J.G.. AU - Wood, Kevin A.. AU - Haitjema, Trinus. AU - Rees, Eileen C.. AU - Jongejans, Eelke. AU - Nolet, B.A.. N1 - 7028, AnE; Data archiving: data archived in Dryad. PY - 2020. Y1 - 2020. N2 - The ability of a species to adapt to environmental change is ultimately reflected in its vital rates - i.e., survival and reproductive success of individuals. Together, vital rates determine trends in numbers, commonly monitored using counts of species abundance. Rapid changes in abundance can give rise to concern, leading to calls for research into the biological mechanisms underlying variations in demography. For the NW European population of Bewicks swan (Cygnus columbianus bewickii), there have been major changes in the population trends recorded during nearly five decades of monitoring (1970‐2016). The total number of birds increased to a maximum of c. 30,000 ...
It is well known that the effective size of a population (Ne) is one of the major determinants of the amount of genetic variation within the population. However, it is unclear whether the types of genetic variations are also dictated by the effective population size. To examine this, we obtained whole genome data from over 100 populations of the world and investigated the patterns of mutational changes. Our results revealed that for low frequency variants, the ratio of AT→GC to GC→AT variants (β) was similar across populations, suggesting the similarity of the pattern of mutation in various populations. However, for high frequency variants, β showed a positive correlation with the effective population size of the populations. This suggests a much higher proportion of high frequency AT→GC variants in large populations (e.g. Africans) compared to those with small population sizes (e.g. Asians). These results imply that the substitution patterns vary significantly between populations. These
The Brookings Center on Social and Economic Dynamics and the Metropolitan Policy Program jointly hosted an NICHD funded Agent Based Modeling and Spatial Population Dynamics Workshop at the Brookings Institution. Researchers from across the country attended the workshop to discuss current projects, to gain insight into agent-based modeling, and to unearth issues for future research collaboration.
The expert said that the growing number of older people would be living with chronic diseases and disability.. Low population density and accelerated levels of urbanisation have the potential to erode the traditional family care system. Further investment by the government in healthcare infrastructure is required to provide alternatives to the older persons in rural areas, she said.. Mr. Kornfeld said that care could no longer be considered simply a family matter. She called on the government to step up its efforts to revise the Aged Persons Act in order to fully provide for the rights, protection, care and welfare of older people.. The expert, who has been in Namibia for the past three weeks, has a chance to meet with older people and representatives of local authorities as well as civil society representatives.. She was presenting preliminary findings on a report which would come out in September.. Kornfeld commended the government for its political determination and vision to improve the ...
To determine whether the early CAFCs induced by STAT5A(1*6) represent true HSCs, a variety of assays were undertaken. First, transduced CB CD34+ cells were sorted into GFP+/CD38low and GFP+/CD38high populations, which were analyzed for CAFC activity on MS5 under limiting dilution conditions. As indicated in Fig. 4 E, most of the CAFCs at day 10 arose from the CD38low population with a frequency of 13.8%, whereas the CD38high population contained some CAFCs at a frequency of 4.5%. Importantly, only the CAFCs generated by the GFP+/CD38low population gave rise to secondary CAFCs when plated onto fresh MS5 stroma, whereas the CAFCs generated from the GFP+/CD38high population did not (Fig. 4 E). Differentiated progeny from secondary CAFCs from the GFP+/CD38low population was monitored by flow cytometry and cytospins. Secondary CAFCs predominantly gave rise to erythroid cells and some myeloid cells (not depicted; see also Fig. 5). Furthermore, day 10 CAFCs were plated in methylcellulose to determine ...
Health, By Alan Mozes HealthDay Reporter ...TUESDAY Sept. 21 (HealthDay News) -- For years researchers have obse...Other well-observed regional factors including low population density...But reporting in the Sept. 15 issue of the American Journal of Psy... There isnt a lot of work that has been done in this area but asthma...,Is,High,Altitude,Linked,to,Suicide,Risk?,medicine,medical news today,latest medical news,medical newsletters,current medical news,latest medicine news
Confirming eradication success can be notoriously difficult and costly, especially when the species is still present but remains undetected, due to very low population densities and imperfect detectio
Adjust m1, m2, s1, and s2 to the right:. As m is increased, the rate of migration from one population to the other is increased. As s is increased, selection against migrants and hybrids is greatest. If both m values are set to the maximum value (while s is set at 0), both populations quickly become more similar until they are indistinguishable. If, however, selection against the migrants is increased, the populations maintain some degree of genetic differentiation.. Note: Pink individuals are hybrids (heterozygotes), green individuals are homozygous for the allele that originated in the upper population, and red individuals are homozygous for the allele that originated in the lower population. The selection coefficient for migrants in the lower population is s1, the selection coefficient for migrants in the upper population is s2, and the selection coefficients for the hybrids are 1/2 that of the migrants for each population.. Hint: If you are using a slow computer, begin with the Time ...
Adjust m1, m2, s1, and s2 to the right:. As m is increased, the rate of migration from one population to the other is increased. As s is increased, selection against migrants and hybrids is greatest. If both m values are set to the maximum value (while s is set at 0), both populations quickly become more similar until they are indistinguishable. If, however, selection against the migrants is increased, the populations maintain some degree of genetic differentiation.. Note: Pink individuals are hybrids (heterozygotes), green individuals are homozygous for the allele that originated in the upper population, and red individuals are homozygous for the allele that originated in the lower population. The selection coefficient for migrants in the lower population is s1, the selection coefficient for migrants in the upper population is s2, and the selection coefficients for the hybrids are 1/2 that of the migrants for each population.. Hint: If you are using a slow computer, begin with the Time ...
Author Summary Underdominance is a component of natural evolution: homozygotes - of either wildtypes or mutants - are advantageous. This can play a role in speciation and as a method to establish artificial genetic constructs in wild populations. The polymorphic state of wildtype and mutant alleles is unstable. However, in subdivided populations limited gene flow can counterbalance this effect. The maintenance of polymorphism sensitively depends on the amount of gene flow. In populations of finite size, the polymorphism is ultimately lost due to stochastic fluctuations, but there are long intermediate periods of polymorphism persistence. We analyze a simple population genetic model to characterize and explore the polymorphic phases depending on population size and genotypic fitness values. Even for large fluctuations (small population size), long periods of neither extinction nor fixation are possible. Since underdominance has been proposed as a genetic strategy in the pest management of disease vectors
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This chapter describes the mechanisms by which an Allee effect can arise. For each mechanism, the chapter discusses how it works in theory, and then presents current evidence for, and examples of, the mechanisms in practice. It begins with reproductive mechanisms, including fertilization efficiency in broadcast spawners, pollen limitation, mate finding, sperm limitation, reproductive facilitation by conspecifics, and female choice. It then moves on to mechanisms related to survival: environmental conditioning and particularly predation, both via the dilution effect and via group behaviour, such as flocking, coloniality, and group vigilence. Finally, the chapter discusses Allee effects in social and cooperative species, where group size is important for both reproduction and survival.
Robert A. Stairs; The concept of population density: A suggestion. Demography 1 May 1977; 14 (2): 243-244. doi: https://doi.org/10.2307/2060580. Download citation file:. ...
To create our high-resolution maps, we use machine learning techniques to identify buildings from commercially available satellite images. Then we work with our partners at Columbia University to overlay general population estimates based on publicly available census data and other population statistics. The resulting maps are the most detailed and actionable tools available for aid and research organizations. For more information about the methodology used to create our high resolution population density maps and the demographic distributions, please visit: https://dataforgood.fb.com/docs/methodology-high-resolution-population-density-maps-demographic-estimates/. For information about how to use HDX to access these datasets, please visit: https://dataforgood.fb.com/docs/high-resolution-population-density-maps-demographic-estimates-documentation/. Adjustments to match the census population with the UN estimates are applied at the national level. The UN estimate for a given country (or ...
Figure 1: An interaction between a male and female koala. The female vocalizes throughout and the male only in the latter part of this recording (~2:56:20s).},{src:https:\/\/www.wildlifeacoustics.com\/uploads\/customer-stories\/whisson\/_389xAUTO_fit_center-center_none\/fig2.png,retina:https:\/\/www.wildlifeacoustics.com\/uploads\/customer-stories\/whisson\/_778xAUTO_fit_center-center_none\/fig2.png,alt:,url:null,target:,caption:. Figure 2: The relationship between koala bellow frequency and population density at four sites on Cape Otway where Songmeters (SM3) were deployed during the 2015-2016 koala breeding season. (Based on 4 x 6h recordings per ...
Figure 5: Excitation Density Dependence of Optical Oxygen Sensing in Poly(9,9-dioctylfluorene) Waveguides Showing Amplified Spontaneous Emission
Thanks to new data from the Federal Reserve, we now know that population density and the ability for a neighborhood to improve may be more connected than previously thought.
To evaluate the effect of plant density and detopping on grain yield, protein content biological yield harvest index, growth indices, number of cob in each plant, No. of row per ear, No. of grain in each row, thousand seed weight of corn (Zea mays L. ar. SC 704), an experiment ...
We contrasted body condition, and age-specific reproduction and mortality between a growing population of sea otters (Enhydralutris) at Kodiak Island and a high-density near-equilibrium population at Amchitka Island, Alaska. We obtained data from marked individuals, population surveys, and collections of beach-cast carcasses. Mass:length ratios indicated that females (but not males) captured in 1992 at Amchitka were in poorer condition than those captured at Kodiak in 1986-1987. In 1993, the condition of females at Amchitka improved in apparent response to two factors: (1) an episodic influx of Pacific smooth lumpsuckers, Aptocyclus ventricocus, from the epi-pelagic zone, which otters consumed; and (2) an increase in the otters benthic invertebrate prey resulting from declining otter numbers. Reproductive rates varied with age (0.37 [CI=0.21 to 0.53] births female−1 yr−1 for 2-3-yr-olds, and 0.83 [CI=0.69 to 0.90] for females ≥4 yr old), and were similar at both areas. Weaning success (pups
Figure 4. Effects of quiescence and heterogeneity of LSCs on population sizes during therapy. A, ϕL = 0.007 ,, ϕH = 0.21 and νL = νH = 0.00024 week−1. The coefficient of variation of population size increases as stem cell counts approach very small numbers, with ranges from 0.17 to 1.2 for LSCs, 0.03 to 0.11 for HSCs, 0.04 to 0.44 for quiescent LSCs (qLSCs), and 0.03 to 0.17 for quiescent HSCs (qHSCs). B, ϕL = ϕH = 0.007 and νL = νH = 0.00024 week−1. C, ϕL = ϕH = 0.007, νL = 0.25, and νH = 0.00024 week−1. In A to C, δL = 0.59, δH = 0.08, βL = βH = 0.024, and αL = αH = 0.07 week−1. D, arrow, increasing δH. In all cases, δ4 = 0.52, δ3 = 0.57, δ2 = 0.62, and δ1 = 0.67. Model 1: δH = 0.08 week−1. Model 2: δH = 0.31 week−1. Model 3: δH = 0.48 week−1. ...
It is currently unclear whether the amino acid substitutions that occur during protein evolution are primarily driven by adaptation, or reflect the random accumulation of neutral changes. When estimated from genomic data, the proportion of adaptive amino acid substitutions, called , was found to vary greatly across species, from nearly zero in humans to above 0.5 in Drosophila. These variations have been interpreted as reflecting differences in effective population size, adaptation being supposedly more efficient in large populations. Here, we investigate the influence of effective popu-lation size and other biological parameters on the rate of adaptive evolution by simulating the evolution of a coding sequence under Fishers geometric formalism. We explicitly model recurrent environmental changes and the subsequent adaptive walks, followed by periods of stasis during which purifying selection dominates. We show that, under a variety of conditions, the effective population size has only a ...
Elephants need space. Across Africa however these iconic creatures are being squeezed into smaller marginal areas as the continents human population rapidly expands. In Kenya, Save the Elephants is working closely with communities, local and national government, wildlife organisations and other stakeholders to find solutions for elephant and man to co-exist in harmony.