Although common sense suggests that environmental influences increasingly account for individual differences in behavior as experiences accumulate during the course of life, this hypothesis has not ...previously been tested, in part because of the large sample sizes needed for an adequately powered analysis. Here we show for general cognitive ability that, to the contrary, genetic influence increases with age. The heritability of general cognitive ability increases significantly and linearly from 41% in childhood (9 years) to 55% in adolescence (12 years) and to 66% in young adulthood (17 years) in a sample of 11 000 pairs of twins from four countries, a larger sample than all previous studies combined. In addition to its far-reaching implications for neuroscience and molecular genetics, this finding suggests new ways of thinking about the interface between nature and nurture during the school years. Why, despite life's 'slings and arrows of outrageous fortune', do genetically driven differences increasingly account for differences in general cognitive ability? We suggest that the answer lies with genotype-environment correlation: as children grow up, they increasingly select, modify and even create their own experiences in part based on their genetic propensities.
Copying other people’s ideas is evaluated negatively by American children and adults. The current study investigated the influence of culture on children’s evaluations of plagiarism by comparing ...children from three countries—the United States, Mexico, and China—that differ in terms of their emphasis on the protection of intellectual property and ideas. Children (3- to 6-year-olds) were presented with videos involving two characters drawing pictures and were asked to evaluate the character who drew unique work or the character who copied someone else’s drawing. The study showed that 5- and 6-year-olds from all three cultures evaluated copiers negatively compared with unique drawers. These results suggest that children from cultures that place different values on the protection of ideas nevertheless develop similar concerns with plagiarism by 5-year-olds.
Pseudomonas aeruginosa is a ubiquitous environmental bacterium that is one of the top three causes of opportunistic human infections. A major factor in its prominence as a pathogen is its intrinsic ...resistance to antibiotics and disinfectants. Here we report the complete sequence of P. aeruginosa strain PAO1. At 6.3 million base pairs, this is the largest bacterial genome sequenced, and the sequence provides insights into the basis of the versatility and intrinsic drug resistance of P. aeruginosa. Consistent with its larger genome size and environmental adaptability, P. aeruginosa contains the highest proportion of regulatory genes observed for a bacterial genome and a large number of genes involved in the catabolism, transport and efflux of organic compounds as well as four potential chemotaxis systems. We propose that the size and complexity of the P. aeruginosa genome reflect an evolutionary adaptation permitting it to thrive in diverse environments and resist the effects of a variety of antimicrobial substances.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Naturally occurring, pharmacologically active peptides constrained with covalent crosslinks generally have shapes that have evolved to fit precisely into binding pockets on their targets. Such ...peptides can have excellent pharmaceutical properties, combining the stability and tissue penetration of small-molecule drugs with the specificity of much larger protein therapeutics. The ability to design constrained peptides with precisely specified tertiary structures would enable the design of shape-complementary inhibitors of arbitrary targets. Here we describe the development of computational methods for accurate de novo design of conformationally restricted peptides, and the use of these methods to design 18-47 residue, disulfide-crosslinked peptides, a subset of which are heterochiral and/or N-C backbone-cyclized. Both genetically encodable and non-canonical peptides are exceptionally stable to thermal and chemical denaturation, and 12 experimentally determined X-ray and NMR structures are nearly identical to the computational design models. The computational design methods and stable scaffolds presented here provide the basis for development of a new generation of peptide-based drugs.
Acute liver failure (ALF) is classically defined by coagulopathy and hepatic encephalopathy (HE); however, acute liver injury (ALI), i.e., severe acute hepatocyte necrosis without HE, has not been ...carefully defined nor studied. Our aim is to describe the clinical course of specifically defined ALI, including the risk and clinical predictors of poor outcomes, namely progression to ALF, the need for liver transplantation (LT) and death.
386 subjects prospectively enrolled in the Acute Liver Failure Study Group registry between 1 September 2008 through 25 October 2013, met criteria for ALI: International Normalized Ratio (INR)≥2.0 and alanine aminotransferase (ALT)≥10 × elevated (irrespective of bilirubin level) for acetaminophen (N-acetyl-p-aminophenol, APAP) ALI, or INR≥2.0, ALT≥10x elevated, and bilirubin≥3.0 mg/dl for non-APAP ALI, both groups without any discernible HE. Subjects who progressed to poor outcomes (ALF, death, LT) were compared, by univariate analysis, with those who recovered. A model to predict poor outcome was developed using the random forest (RF) procedure.
Progression to a poor outcome occurred in 90/386 (23%), primarily in non-APAP (71/179, 40%) vs. only 14/194 (7.2%) in APAP patients comprising 52% of all cases (13 cases did not have an etiology assigned; 5 of whom had a poor outcome). Of 82 variables entered into the RF procedure: etiology, bilirubin, INR, APAP level and duration of jaundice were the most predictive of progression to ALF, LT, or death.
A majority of ALI cases are due to APAP, 93% of whom will improve rapidly and fully recover, while non-APAP patients have a far greater risk of poor outcome and should be targeted for early referral to a liver transplant center.
Soil organic carbon distribution within soil profile is highly influenced by management practices, especially tillage systems where soil environment is altered. Such changes in soil environment will ...affect soil carbon retention or accumulation in different layers of the soil profile. However, much published research in the area of soil organic carbon (SOC) sequestration focuses on shallow sampling depths within the 0–30cm tillage zone when determining SOC stocks and sequestration. The objectives of this study are to quantify the SOC stock differences with depth between tillage treatments after 20years and to determine the appropriate sampling depth when assessing SOC stocks as influenced by management practices. A 20-year moldboard plow (MP), chisel plow (CP) and no-tillage (NT) study was established with a maize–soybean rotation. The 75-cm root zone was sampled in 5-cm intervals to measure SOC stocks. The SOC sequestration, storage, retention and loss were determined for the 0–5cm, 0–15cm, 15–75cm and 0–75cm layers. The NT treatment did retain more SOC stock than the MP treatment to a 20cm depth but the SOC stock of the 20–35cm layer NT system was lower than the MP system. It is recommended that the depth of soil sampling has to include the entire root zone to accurately report SOC stock and the effect of tillage system on change in SOC.
•When a soil is sampled to different depths the SOC stock change varies.•When only the 0–5cm layer was sampled SOC sequestration did occur.•When root zone sampled the losses were greater than the 0–5cm gains.•No SOC sequestration occurred for a 75cm root zone.•NT treatment lost more SOC stock in 5 to 30cm layer than MP.
Hibernation consists of extended durations of torpor interrupted by periodic arousals. The 'dehydration hypothesis' proposes that hibernating mammals arouse to replenish water lost through ...evaporation during torpor. Arousals are energetically expensive, and increased arousal frequency can alter survival throughout hibernation. Yet we lack a means to assess the effect of evaporative water loss (EWL), determined by animal physiology and hibernation microclimate, on torpor bout duration and subsequent survival. White-nose syndrome (WNS), a devastating disease impacting hibernating bats, causes increased frequency of arousals during hibernation and EWL has been hypothesized to contribute to this increased arousal frequency. WNS is caused by a fungus, which grows well in humid hibernaculum environments and damages wing tissue important for water conservation. Here, we integrated the effect of EWL on torpor expression in a hibernation energetics model, including the effects of fungal infection, to determine the link between EWL and survival. We collected field data for Myotis lucifugus, a species that experiences high mortality from WNS, to gather parameters for the model. In saturating conditions, we predicted healthy bats experience minimal mortality. Infected bats, however, suffer high fungal growth in highly saturated environments, leading to exhaustion of fat stores before spring. Our results suggest that host adaptation to humid environments leads to increased arousal frequency from infection, which drives mortality across hibernaculum conditions. Our modified hibernation model provides a tool to assess the interplay between host physiology, hibernaculum microclimate, and diseases such as WNS on winter survival.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In laboratory experiments using the engineering spare microcalorimeter detector from the ASTRO-E satellite mission, we recorded the x-ray emission of highly charged ions of carbon, nitrogen, and ...oxygen, which simulates charge exchange reactions between heavy ions in the solar wind and neutral gases in cometary comae. The spectra are complex and do not readily match predictions. We developed a charge exchange emission model that successfully reproduces the soft x-ray spectrum of comet Linear C/1999 S4, observed with the Chandra X-ray Observatory.
Connectivity of Marine Populations: Open or Closed? Cowen, Robert K.; Kamazima M. M. Lwiza; Sponaugle, Su ...
Science (American Association for the Advancement of Science),
02/2000, Letnik:
287, Številka:
5454
Journal Article
Recenzirano
Most marine populations are thought to be well connected via long-distance dispersal of larval stages. Eulerian and Lagrangian flow models, coupled with linear mortality estimates, were used to ...examine this assumption. The findings show that when simple advection models are used, larval exchange rates may be overestimated; such simplistic models fail to account for a decrease of up to nine orders of magnitude in larval concentrations resulting from diffusion and mortality. The alternative process of larval retention near local populations is shown to exist and may be of great importance in the maintenance of marine population structure and management of coastal marine resources.
Hibernation is widespread among mammals in a variety of environmental contexts. However, few experimental studies consider interspecific comparisons, which may provide insight into general patterns ...of hibernation strategies. We studied 13 species of free-living bats, including populations spread over thousands of kilometers and diverse habitats. We measured torpid metabolic rate (TMR) and evaporative water loss (two key parameters for understanding hibernation energetics) across a range of temperatures. There was no difference in minimum TMR among species (i.e., all species achieved similarly low torpid metabolic rate) but the temperature associated with minimum TMR varied among species. The minimum defended temperature (temperature below which TMR increased) varied from 8 °C to < 2 °C among species. Conversely, evaporative water loss varied among species, with species clustered in two groups representing high and low evaporative water loss. Notably, species that have suffered population declines due to white-nose syndrome fall in the high evaporative water loss group and less affected species in the low evaporative water loss group. Documenting general patterns of physiological diversity, and associated ecological implications, contributes to broader understanding of biodiversity, and may help predict which species are at greater risk of environmental and anthropogenic stressors.
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