20,032 research outputs found
A model of gas buildup and release in crater lakes
The sudden release of carbon dioxide gas, which may accumulate gradually within the stratified water bodies of a crater lake, caused two fatal disasters in Cameroon during the past decade. We model the various processes that may have led to the release by considering (1) gas injection, (2) an internal triggering mechanism, (3) propagation of a disturbance after triggering, and (4) the forces that end the outburst. We suggest that the 1986 Lake Nyos outburst was triggered at the lake bottom. The final explosive stage of the release ended quickly when a sufficiently large volume of gas bubbles prevented circulation of water eddies within the lake. A cellular automaton model is used to estimate the amount of carbon dioxide gas released and the characteristic time interval between successive outbursts. If both the gas accumulation rate and the diffusion rate of carbon dioxide through water are constant, then rapid gas release, will occur at fairly regular intervals. In which case, the amount of gas released from Lake Nyos is 0.17±0.05 km3 at standard temperature and pressure each 37±10 years. It is possible, however, that an external event could trigger a sudden release or that the diffusion rate of carbon dioxide may change as more gas accumulates, which could shorten the release time.published_or_final_versio
Ozone autohaemotherapy protects against ketamine hydrochloride® induced liver and muscle damage in baboons
Ozone is currently under scrutiny because of various claims of beneficial effect in disease. In order to shed some light on this we assessed the acute and chronic effect of O3 autohaemotherapy (AHT) on liver and muscle damage in baboons. Five percent of the total blood volume of a baboon was treated with O2 and O3. Eleven baboons were acutely treated with an O2/O3 gas mixture containing 20, 40 and 80ìg/ml ozone. Five were treated with pure O2 and three received no treatment to assess the effect of the ketamine hydrochloride anaesthesia. Blood samples were collected before treatment and after 4, 24 and 48 h. Anaesthesia increased aspartate aminotransferase (AST), alanine aminotransferase (ALT) and creatine kinase (CK) levels markedly. O3-AHT had a protective effect, since enzyme levels were lower. O2-AHT had no protective effect on liver and muscle damage. An O2/O3 gas mixture containing 40 ìg/ml O3 was used for chronic O3-AHT (n=6) treatment. The animals were treated at 0, 24 and 48 h. Blood was collected before treatment and again after 4, 24, 28, 48, 52, 72 and 96 h. ALT levels increased and remained elevated. AST levels increased during the four hours following each treatment and remainedelevated. CK levels increased markedly during the four hours following treatment, but decreased after treatment was stopped. The magnitude of changes was small and does not support the view that infusion of ozonated of blood is toxic
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General Psychopathology and Dysregulation Profile in a Longitudinal Community Sample: Stability, Antecedents and Outcomes.
The general factor of psychopathology (GP, or p factor) and the Dysregulation Profile (DP) are two conceptually similar, but independently developed approaches to understand psychopathology. GP and DP models and their stability, antecedents and outcomes are studied in a longitudinal sample of 1073 children (49.8% female). GP and DP models were estimated at ages 8 and 14 years using the parent-reported Child Behavior Checklist (CBCL) and Youth Self Report (YSR). Early childhood antecedents and adolescent outcomes were derived using a multi-method multi-informant approach. Results showed that the general GP and DP had similar key symptoms and were similarly related to early-childhood antecedents (e.g., lower effortful control, higher maternal depression) and adolescent outcomes (e.g., reduced academic functioning, poorer mental health). This study demonstrates that GP and DP are highly similar constructs in middle childhood and adolescence, both describing a general vulnerability for psychopathology with (emotional) dysregulation at its core. Scientific integration of these approaches could lead to a better understanding of the structure, antecedents and outcomes of psychopathology
Exploring Food Detection using CNNs
One of the most common critical factors directly related to the cause of a
chronic disease is unhealthy diet consumption. In this sense, building an
automatic system for food analysis could allow a better understanding of the
nutritional information with respect to the food eaten and thus it could help
in taking corrective actions in order to consume a better diet. The Computer
Vision community has focused its efforts on several areas involved in the
visual food analysis such as: food detection, food recognition, food
localization, portion estimation, among others. For food detection, the best
results evidenced in the state of the art were obtained using Convolutional
Neural Network. However, the results of all these different approaches were
gotten on different datasets and therefore are not directly comparable. This
article proposes an overview of the last advances on food detection and an
optimal model based on GoogLeNet Convolutional Neural Network method, principal
component analysis, and a support vector machine that outperforms the state of
the art on two public food/non-food datasets
Rapid generation of chromosome-specific alphoid DNA probes using the polymerase chain reaction
Non-isotopic in situ hybridization of chromosome-specific alphoid DNA probes has become a potent tool in the study of numerical aberrations of specific human chromosomes at all stages of the cell cycle. In this paper, we describe approaches for the rapid generation of such probes using the polymerase chain reaction (PCR), and demonstrate their chromosome specificity by fluorescence in situ hybridization to normal human metaphase spreads and interphase nuclei. Oligonucleotide primers for conserved regions of the alpha satellite monomer were used to generate chromosome-specific DNA probes from somatic hybrid cells containing various human chromosomes, and from DNA libraries from sorted human chromosomes. Oligonucleotide primers for chromosome-specific regions of the alpha satellite monomer were used to generate specific DNA probes for the pericentromeric heterochromatin of human chromosomes 1, 6, 7, 17 and X directly from human genomic DNA
The success-index: an alternative approach to the h-index for evaluating an individual's research output
Among the most recent bibliometric indicators for normalizing the differences among fields of science in terms of citation behaviour, Kosmulski (J Informetr 5(3):481-485, 2011) proposed the NSP (number of successful paper) index. According to the authors, NSP deserves much attention for its great simplicity and immediate meaning— equivalent to those of the h-index—while it has the disadvantage of being prone to manipulation and not very efficient in terms of statistical significance. In the first part of the paper, we introduce the success-index, aimed at reducing the NSP-index's limitations, although requiring more computing effort. Next, we present a detailed analysis of the success-index from the point of view of its operational properties and a comparison with the h-index's ones. Particularly interesting is the examination of the success-index scale of measurement, which is much richer than the h-index's. This makes success-index much more versatile for different types of analysis—e.g., (cross-field) comparisons of the scientific output of (1) individual researchers, (2) researchers with different seniority, (3) research institutions of different size, (4) scientific journals, etc
A Rejoinder on Energy versus Impact Indicators
Citation distributions are so skewed that using the mean or any other central
tendency measure is ill-advised. Unlike G. Prathap's scalar measures (Energy,
Exergy, and Entropy or EEE), the Integrated Impact Indicator (I3) is based on
non-parametric statistics using the (100) percentiles of the distribution.
Observed values can be tested against expected ones; impact can be qualified at
the article level and then aggregated.Comment: Scientometrics, in pres
The substantive and practical significance of citation impact differences between institutions: Guidelines for the analysis of percentiles using effect sizes and confidence intervals
In our chapter we address the statistical analysis of percentiles: How should
the citation impact of institutions be compared? In educational and
psychological testing, percentiles are already used widely as a standard to
evaluate an individual's test scores - intelligence tests for example - by
comparing them with the percentiles of a calibrated sample. Percentiles, or
percentile rank classes, are also a very suitable method for bibliometrics to
normalize citations of publications in terms of the subject category and the
publication year and, unlike the mean-based indicators (the relative citation
rates), percentiles are scarcely affected by skewed distributions of citations.
The percentile of a certain publication provides information about the citation
impact this publication has achieved in comparison to other similar
publications in the same subject category and publication year. Analyses of
percentiles, however, have not always been presented in the most effective and
meaningful way. New APA guidelines (American Psychological Association, 2010)
suggest a lesser emphasis on significance tests and a greater emphasis on the
substantive and practical significance of findings. Drawing on work by Cumming
(2012) we show how examinations of effect sizes (e.g. Cohen's d statistic) and
confidence intervals can lead to a clear understanding of citation impact
differences
The Retinome – Defining a reference transcriptome of the adult mammalian retina/retinal pigment epithelium
BACKGROUND: The mammalian retina is a valuable model system to study neuronal biology in health and disease. To obtain insight into intrinsic processes of the retina, great efforts are directed towards the identification and characterization of transcripts with functional relevance to this tissue. RESULTS: With the goal to assemble a first genome-wide reference transcriptome of the adult mammalian retina, referred to as the retinome, we have extracted 13,037 non-redundant annotated genes from nearly 500,000 published datasets on redundant retina/retinal pigment epithelium (RPE) transcripts. The data were generated from 27 independent studies employing a wide range of molecular and biocomputational approaches. Comparison to known retina-/RPE-specific pathways and established retinal gene networks suggest that the reference retinome may represent up to 90% of the retinal transcripts. We show that the distribution of retinal genes along the chromosomes is not random but exhibits a higher order organization closely following the previously observed clustering of genes with increased expression. CONCLUSION: The genome wide retinome map offers a rational basis for selecting suggestive candidate genes for hereditary as well as complex retinal diseases facilitating elaborate studies into normal and pathological pathways. To make this unique resource freely available we have built a database providing a query interface to the reference retinome [1]
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