699 research outputs found

    The effect of thermal variance on the phenotype of marine turtle offspring.

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    PublishedJournal ArticleTemperature can have a profound effect on the phenotype of reptilian offspring, yet the bulk of current research considers the effects of constant incubation temperatures on offspring morphology, with few studies examining the natural thermal variance that occurs in the wild. Over two consecutive nesting seasons, we placed temperature data loggers in 57 naturally incubating clutches of loggerhead sea turtles Caretta caretta and found that greater diel thermal variance during incubation significantly reduced offspring mass, potentially reducing survival of hatchlings during their journey from the nest to offshore waters and beyond. With predicted scenarios of climate change, behavioral plasticity in nest site selection may be key for the survival of ectothermic species, particularly those with temperature-dependent sex determination.We thank all the volunteers of the Marine Turtle Conservation Project (northern Cyprus) who aided in data collection during the 2011/2012 nesting seasons. This work would not have been possible without the Society for the Protection of Turtles (SPOT) and the Department for Environmental Protection. For their continued support we thank the British Chelonia Group, the British High Commission, the British Resident’s Society, Ektam Kıbrıs, Erwin Warth Foundation, Friends of SPOT, Gemini Dataloggers (UK), and Kuzey Kıbrıs Turkcell

    Detecting green shoots of recovery: The importance of long-term individual-based monitoring of marine turtles

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    This is the author accepted manuscript. The final version is available from Wiley via the DOI in this recordPopulation monitoring is an essential part of evaluating the effectiveness of management interventions for conservation. Coastal breeding aggregations of marine vertebrate species that come ashore to pup or nest provide an opportunistic window of observation into otherwise widely dispersed populations. Green turtle (Chelonia mydas) nesting on the north and west coasts of northern Cyprus has been monitored consistently and exhaustively since 1993, with an intensive saturation tagging programme running at one key site for the same duration. This historically depleted nesting population is showing signs of recovery, possibly in response to nest protection approaching two decades, with increasing nest numbers and rising levels of recruitment. Strong correlation between year-to-year magnitude of nesting and the proportion of new breeders in the nesting cohort implies that recruitment of new individuals to the breeding population is an important driver of this recovery trend. Recent changes in fishing activities may be impacting the local juvenile neritic stage, however, which may hinder this potential recovery. Individuals returning to breed after two years laid fewer clutches than those returning after three or four years, demonstrating a trade-off between remigration interval and breeding output. Average clutch frequencies have remained stable around a median of three clutches a year per female despite the demographic shift towards new nesters, which typically lay fewer clutches in their first season. We show that where local fecundity has been adequately assessed, the use of average clutch frequencies can be a reliable method for deriving nester abundance from nest counts. Index sites where individual-based monitoring is possible will be important in monitoring long-term climate driven changes in reproductive rates.European Social Fun

    Illuminating Choices for Library Prep: A Comparison of Library Preparation Methods for Whole Genome Sequencing of Cryptococcus neoformans Using Illumina HiSeq.

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    The industry of next-generation sequencing is constantly evolving, with novel library preparation methods and new sequencing machines being released by the major sequencing technology companies annually. The Illumina TruSeq v2 library preparation method was the most widely used kit and the market leader; however, it has now been discontinued, and in 2013 was replaced by the TruSeq Nano and TruSeq PCR-free methods, leaving a gap in knowledge regarding which is the most appropriate library preparation method to use. Here, we used isolates from the pathogenic fungi Cryptococcus neoformans var. grubii and sequenced them using the existing TruSeq DNA v2 kit (Illumina), along with two new kits: the TruSeq Nano DNA kit (Illumina) and the NEBNext Ultra DNA kit (New England Biolabs) to provide a comparison. Compared to the original TruSeq DNA v2 kit, both newer kits gave equivalent or better sequencing data, with increased coverage. When comparing the two newer kits, we found little difference in cost and workflow, with the NEBNext Ultra both slightly cheaper and faster than the TruSeq Nano. However, the quality of data generated using the TruSeq Nano DNA kit was superior due to higher coverage at regions of low GC content, and more SNPs identified. Researchers should therefore evaluate their resources and the type of application (and hence data quality) being considered when ultimately deciding on which library prep method to use

    Evaluation of the Acute Oral Toxicity Class of Trinuclear Chromium(III) Glycinate Complex in Rat

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    Chromium(III) is considered as an essential element playing a role in carbohydrate and lipid metabolism, and various chemical forms of this element are widely used in dietary supplements. A new trinuclear chromium(III) glycinate complex [Cr3O(NH2CH2CO2)6(H2O)3]+NO3− (CrGly), an analogue of Cr3 (trinuclear Cr(III) propionate complex) has been synthesized as a potential source of supplementary Cr. In this study, we evaluated the acute toxicity class of CrGly in Wistar rats applying the OECD 423 procedure. Male and female Wistar rats (n = 12, 6 ♀ and 6 ♂) were given by gavage either a single dose of CrGly 2,000 mg/kg body mass (equals to 300 mg Cr(III)/kg body mass; in aqueous solution) or equivalent volumes of distilled water and fed ad libitum commercial Labofeed B diet, and observed carefully for 14 days, then sacrificed to collect blood and internal organs for biochemical and histologic examination. No death cases were detected. No abnormalities in animal behavior, body mass gains, gross organ histology, or blood morphology and biochemistry were observed. The results demonstrate that LD50 of CrGly is greater than 2,000 mg/kg when administrated orally to rat; thus, this compound appears to belong to the fifth category in the GHS system or the fourth class (“unclassified”) in the EU classification system

    Representation of Time-Varying Stimuli by a Network Exhibiting Oscillations on a Faster Time Scale

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    Sensory processing is associated with gamma frequency oscillations (30–80 Hz) in sensory cortices. This raises the question whether gamma oscillations can be directly involved in the representation of time-varying stimuli, including stimuli whose time scale is longer than a gamma cycle. We are interested in the ability of the system to reliably distinguish different stimuli while being robust to stimulus variations such as uniform time-warp. We address this issue with a dynamical model of spiking neurons and study the response to an asymmetric sawtooth input current over a range of shape parameters. These parameters describe how fast the input current rises and falls in time. Our network consists of inhibitory and excitatory populations that are sufficient for generating oscillations in the gamma range. The oscillations period is about one-third of the stimulus duration. Embedded in this network is a subpopulation of excitatory cells that respond to the sawtooth stimulus and a subpopulation of cells that respond to an onset cue. The intrinsic gamma oscillations generate a temporally sparse code for the external stimuli. In this code, an excitatory cell may fire a single spike during a gamma cycle, depending on its tuning properties and on the temporal structure of the specific input; the identity of the stimulus is coded by the list of excitatory cells that fire during each cycle. We quantify the properties of this representation in a series of simulations and show that the sparseness of the code makes it robust to uniform warping of the time scale. We find that resetting of the oscillation phase at stimulus onset is important for a reliable representation of the stimulus and that there is a tradeoff between the resolution of the neural representation of the stimulus and robustness to time-warp. Author Summary Sensory processing of time-varying stimuli, such as speech, is associated with high-frequency oscillatory cortical activity, the functional significance of which is still unknown. One possibility is that the oscillations are part of a stimulus-encoding mechanism. Here, we investigate a computational model of such a mechanism, a spiking neuronal network whose intrinsic oscillations interact with external input (waveforms simulating short speech segments in a single acoustic frequency band) to encode stimuli that extend over a time interval longer than the oscillation's period. The network implements a temporally sparse encoding, whose robustness to time warping and neuronal noise we quantify. To our knowledge, this study is the first to demonstrate that a biophysically plausible model of oscillations occurring in the processing of auditory input may generate a representation of signals that span multiple oscillation cycles.National Science Foundation (DMS-0211505); Burroughs Wellcome Fund; U.S. Air Force Office of Scientific Researc

    Quantitative evaluation of recall and precision of CAT Crawler, a search engine specialized on retrieval of Critically Appraised Topics

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    BACKGROUND: Critically Appraised Topics (CATs) are a useful tool that helps physicians to make clinical decisions as the healthcare moves towards the practice of Evidence-Based Medicine (EBM). The fast growing World Wide Web has provided a place for physicians to share their appraised topics online, but an increasing amount of time is needed to find a particular topic within such a rich repository. METHODS: A web-based application, namely the CAT Crawler, was developed by Singapore's Bioinformatics Institute to allow physicians to adequately access available appraised topics on the Internet. A meta-search engine, as the core component of the application, finds relevant topics following keyword input. The primary objective of the work presented here is to evaluate the quantity and quality of search results obtained from the meta-search engine of the CAT Crawler by comparing them with those obtained from two individual CAT search engines. From the CAT libraries at these two sites, all possible keywords were extracted using a keyword extractor. Of those common to both libraries, ten were randomly chosen for evaluation. All ten were submitted to the two search engines individually, and through the meta-search engine of the CAT Crawler. Search results were evaluated for relevance both by medical amateurs and professionals, and the respective recall and precision were calculated. RESULTS: While achieving an identical recall, the meta-search engine showed a precision of 77.26% (±14.45) compared to the individual search engines' 52.65% (±12.0) (p < 0.001). CONCLUSION: The results demonstrate the validity of the CAT Crawler meta-search engine approach. The improved precision due to inherent filters underlines the practical usefulness of this tool for clinicians

    Genetics of CM-proteins (A-hordeins) in barley

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    The CM-proteins, which are the main components of the A-hordeins, include four previously described proteins (CMa-1, CMb-1, CMc-1, CMd-1), plus a new one, CMe-1, which has been tentatively included in this group on the basis of its solubility properties and electrophoretic mobility. The variability of the five proteins has been investigated among 38 Hordeum vulgare cultivars and 17 H. spontaneum accessions. Proteins CMa-1, CMc-1 and CMd-1 were invariant within the cultivated species; CMd was also invariant in the wild one. The inheritance of variants CMb-1/CMb-2 and CMe-1/CMe-2,2 was studied in a cross H. spontaneum x H. vulgare. The first two proteins were inherited as codominantly expressed allelic variations of a single mendelian gene. Components CMe-2,2 were jointly inherited and codominantly expressed with respect to CMe-1. Gene CMb and gene(s) CMe were found to be unlinked. The chromosomal locations of genes encoding CM-proteins were investigated using wheat-barley addition lines. Genes CMa and CMc were associated with chromosome 1, and genes CMb and CMd with chromosome 4. These gene locations further support the proposed homoeology of chromosomes 1 and 4 of barley with chromosomes groups 7 and 4 of wheat, respectively. Gene(s) CMe has been assigned to chromosome 3 of barley. The accumulation of protein CMe-1 is totally blocked in the high lysine mutant Riso 1508 and partially so in the high lysine barley Hiproly

    Spreading Patterns of the Influenza A (H1N1) Pandemic

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    We investigate the dynamics of the 2009 influenza A (H1N1/S-OIV) pandemic by analyzing data obtained from World Health Organization containing the total number of laboratory-confirmed cases of infections - by country - in a period of 69 days, from 26 April to 3 July, 2009. Specifically, we find evidence of exponential growth in the total number of confirmed cases and linear growth in the number of countries with confirmed cases. We also find that, i) at early stages, the cumulative distribution of cases among countries exhibits linear behavior on log-log scale, being well approximated by a power law decay; ii) for larger times, the cumulative distribution presents a systematic curvature on log-log scale, indicating a gradual change to lognormal behavior. Finally, we compare these empirical findings with the predictions of a simple stochastic model. Our results could help to select more realistic models of the dynamics of influenza-type pandemics
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