A standardized method for analysis of Medicago truncatula phenotypic development.
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Medicago truncatula has become a model system to study legume biology. It is imperative that detailed growth characteristics of the most commonly used cultivar, line A17 cv Jemalong, be documented. Such analysis creates a basis to analyze phenotypic alterations due to genetic lesions or environmental stress and is essential to characterize gene function and its relationship to morphological development. We have documented morphological development of M. truncatula to characterize its temporal developmental growth pattern; developed a numerical nomenclature coding system that identifies stages in morphological development; tested the coding system to identify phenotypic differences under phosphorus (P) and nitrogen (N) deprivation; and created visual models using the L-system formalism. The numerical nomenclature coding system, based on a series of defined growth units, represents incremental steps in morphological development. Included is a decimal component dividing growth units into nine substages. A measurement component helps distinguish alterations that may be missed by the coding system. Growth under N and P deprivation produced morphological alterations that were distinguishable using the coding system and its measurement component. N and P deprivation resulted in delayed leaf development and expansion, delayed axillary shoot emergence and elongation, decreased leaf and shoot size, and altered root growth. Timing and frequency of flower emergence in P-deprived plants was affected. This numerical coding system may be used as a standardized method to analyze phenotypic variation in M. truncatula due to nutrient stress, genetic lesions, or other factors and should allow valid growth comparisons across geographically distant laboratories. (+info)
Effectiveness of bans and laws in reducing traffic deaths: legalized Sunday packaged alcohol sales and alcohol-related traffic crashes and crash fatalities in New Mexico.
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We determined the relative risk of alcohol-related motor vehicle accidents and fatalities after New Mexico lifted its ban on Sunday packaged alcohol sales. We extracted all alcohol-related crashes from New Mexico police reports for 3652 days between July 1, 1990, and June 30, 2000, and found a 29% increase in alcohol-related crashes and a 42% increase in alcohol-related crash fatalities on Sundays after the ban on Sunday packaged alcohol sales was lifted. There was an estimated excess of 543.1 alcohol-related crashes and 41.6 alcohol-related crash fatalities on Sundays after the ban was lifted. Repealing the ban on Sunday packaged alcohol sales introduced a public health and safety hazard in New Mexico. (+info)
Paleontological evidence to date the tree of life.
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The role of fossils in dating the tree of life has been misunderstood. Fossils can provide good "minimum" age estimates for branches in the tree, but "maximum" constraints on those ages are poorer. Current debates about which are the "best" fossil dates for calibration move to consideration of the most appropriate constraints on the ages of tree nodes. Because fossil-based dates are constraints, and because molecular evolution is not perfectly clock-like, analysts should use more rather than fewer dates, but there has to be a balance between many genes and few dates versus many dates and few genes. We provide "hard" minimum and "soft" maximum age constraints for 30 divergences among key genome model organisms; these should contribute to better understanding of the dating of the animal tree of life. (+info)
Prefrontal neural correlates of memory for sequences.
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The sequence of actions appropriate to solve a problem often needs to be discovered by trial and error and recalled in the future when faced with the same problem. Here, we show that when monkeys had to discover and then remember a sequence of decisions across trials, ensembles of prefrontal cortex neurons reflected the sequence of decisions the animal would make throughout the interval between trials. This signal could reflect either an explicit memory process or a sequence-planning process that begins far in advance of the actual sequence execution. This finding extended to error trials such that, when the neural activity during the intertrial interval specified the wrong sequence, the animal also attempted to execute an incorrect sequence. More specifically, we used a decoding analysis to predict the sequence the monkey was planning to execute at the end of the fore-period, just before sequence execution. When this analysis was applied to error trials, we were able to predict where in the sequence the error would occur, up to three movements into the future. This suggests that prefrontal neural activity can retain information about sequences between trials, and that regardless of whether information is remembered correctly or incorrectly, the prefrontal activity veridically reflects the animal's action plan. (+info)
Pneumothorax after insertion of central venous catheters in the intensive care unit: association with month of year and week of month.
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RATIONALE: One of the complications associated with insertion of central venous catheters (CVCs) is pneumothorax (PTX). Because of housestaff inexperience, it was hypothesised that rates of PTX after insertion of CVCs in teaching hospitals would be highest in July and August and in the first week of the month (beginning of intensive care unit (ICU) rotation). METHODS: In a retrospective analysis of data from patients admitted to the ICU in two tertiary care teaching hospitals in British Columbia from 1999 to 2005, rates of PTX occurring after insertion of CVCs were calculated, and it was evaluated whether rates were increased during certain times of the year/month. RESULTS: During this period, 3548 patients were admitted to these ICUs and had at least one CVC placed. 5816 CVCs were inserted; 113 PTX occurred within 2 days after insertions (1.9% per CVC). The rate during the last week of the month was greater (2.7%) than during the first, second or third weeks (1.7%, 1.8% and 1.4%, respectively). This effect persisted after controlling for the Acute Physiology and Chronic Health Evaluation II score, the number of catheters placed per patient, gender, age and hospital. Rates of PTX after catheter placement did not vary by the month of the year. CONCLUSIONS: The rate of PTX after insertion of CVCs is greatest in the last week of the month. If this effect can be verified in other centres, increased supervision of residents at the end of ICU rotations when placing CVCs should be considered. Whether this effect applies to other patient safety outcomes in the ICU also needs further study. (+info)
Chromatin polymorphism and the nucleosome superfamily: a genealogy.
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Nucleosomes were discovered more than thirty years ago as the basic repeating units of chromatin. Since then, nucleosomes have progressively revealed their taste to come in many appearances, upon either adjunction of other proteins (e.g., a fifth histone or a nonhistone protein, HMG-N), histone substitution for isoforms (histone variants), depletion of one or the two H2A-H2B dimers (sub-nucleosomes), intimate two-particle association, or isomeric structural alterations. The resulting entities, some of them are only transient, acquire new properties useful for their specific roles in chromatin function. These structures are presented here in the chronological order of their identification, from the chromatosome to the sub-nucleosomal hexasome and tetrasome, and from the dinucleosomal altosome and nucleodisome to the nucleosome variants and altered forms: the old lexosome and the most recent reversome. (+info)
Filicide in Austria and Finland--a register-based study on all filicide cases in Austria and Finland 1995-2005.
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