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1.
Sci Rep ; 13(1): 18510, 2023 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-37898713

RESUMO

This work presents a comprehensive approach to reduce bias in word embedding vectors and evaluate the impact on various Natural Language Processing (NLP) tasks. Two GloVe variations (840B and 50) are debiased by identifying the gender direction in the word embedding space and then removing or reducing the gender component from the embeddings of target words, while preserving useful semantic information. Their gender bias is assessed through the Word Embedding Association Test. The performance of co-reference resolution and text classification models trained on both original and debiased embeddings is evaluated in terms of accuracy. A compressed co-reference resolution model is examined to gauge the effectiveness of debiasing techniques on resource-efficient models. To the best of the authors' knowledge, this is the first attempt to apply compression techniques to debiased models. By analyzing the context preservation of debiased embeddings using a Twitter misinformation dataset, this study contributes valuable insights into the practical implications of debiasing methods for real-world applications such as person profiling.

2.
Accid Anal Prev ; 151: 105946, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33385963

RESUMO

Crash relative risk estimates (CRREs) during rain, snow, sleet (i.e., ice pellets), and freezing rain are estimated using a matched-pair analysis in Kansas for the years 1995-2014. Variable-length event periods are defined using both crash reports and nearby Automated Surface Observing System (ASOS) and Automated Weather Observing System (AWOS) observations. Newly developed methods to extract precipitation-type beginning and ending times within ASOS/AWOS observations provide the most accurate account of precipitation type to compute CRREs. Crash relative risk is enhanced during any precipitation type, while a hierarchy of risk based on precipitation type is also evident. For property damage only crashes, CRREs during freezing rain are significantly higher than snow, which in turn are significantly higher than rain. CRREs during sleet, though statistically significantly higher than rain, are not statistically significantly different from snow or freezing rain. For casualty (injury and/or fatality) crashes, CRREs during snow and freezing rain are significantly higher than rain, but the increase in risk during sleet is not statistically significantly higher than rain. These results are consistent with expectations, but are quantified here for the first time. These hierarchies are insensitive to the use of all crashes versus only those with crash-reported precipitation or precipitation-induced roadway surface conditions to compute CRREs. The risk of a single-vehicle crash is higher than a multiple-vehicle crash during snow, sleet, and freezing rain, whereas the opposite was found for rain. This hierarchy is most prominent during weekdays before noon.


Assuntos
Acidentes de Trânsito , Humanos , Kansas/epidemiologia , Chuva , Risco , Neve
3.
Accid Anal Prev ; 130: 22-29, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29402401

RESUMO

Numerous studies have examined the influence of rainfall on the relative risk of crash, and they all agree that rainfall leads to an increase in relative risk as compared to dry conditions; what they do not agree on is the magnitude of these increases. Here we consider three methodological decisions made in computing the relative risk and examine their impacts: the inclusion or exclusion of zero total events (where no crashes occur during event or control periods), the temporal scale of analysis, and the use of information on pavement and weather conditions contained with the crash reports to determine relative risk. Our analyses are based on several years of data from six U.S. states (Arkansas, Georgia, Illinois, Maryland, Minnesota and Ohio). Zero total events in the context of weather related crash studies typically provide no information on the actual crash odds and greatly alter the distribution of relative risk estimates and should be removed from the analysis. While the use of a daily time step provides an estimate of relative risk that is not significantly different from an hourly time step for the majority of rural counties in our study area, the same is true of only 39% of the urban counties. Finally, the use of pavement and weather condition information from the crash reports results in relative risk estimates that are lower than the standard approach, however this difference decreases as rainfall totals increase. By highlighting the influence of methodological choices, we hope to pave the way towards the potential reduction in uncertainties in weather-related relative risk estimates.


Assuntos
Acidentes de Trânsito/estatística & dados numéricos , Chuva , Humanos , Razão de Chances , Risco , Medição de Risco , Estados Unidos
4.
J Biol Chem ; 289(28): 19395-407, 2014 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-24849599

RESUMO

The human pathogen Neisseria meningitidis (Nm) is a leading cause of bacterial meningitis and sepsis globally. A major virulence factor of Nm is the capsular polysaccharide (CPS), which in Nm serogroup A consists of N-acetyl-mannosamine-1-phosphate units linked together by phosphodiester linkages [ → 6)-α-D-ManNAc-(1 → OPO3 (-)→]n. Acetylation in O-3 (to a minor extent in O-4) position results in immunologically active polymer. In the capsule gene cluster (cps) of Nm, region A contains the genetic information for CPSA biosynthesis. Thereby the open reading frames csaA, -B, and -C are thought to encode the UDP-N-acetyl-D-glucosamine-2-epimerase, poly-ManNAc-1-phosphate-transferase, and O-acetyltransferase, respectively. With the aim to use a minimal number of recombinant enzymes to produce immunologically active CPSA, we cloned the genes csaA, csaB, and csaC and functionally characterized the purified recombinant proteins. If recombinant CsaA and CsaB were combined in one reaction tube, priming CPSA-oligosaccharides were efficiently elongated with UDP-GlcNAc as the donor substrate, confirming that CsaA is the functional UDP-N-acetyl-D-glucosamine-2-epimerase and CsaB the functional poly-ManNAc-1-phosphate-transferase. Subsequently, CsaB was shown to transfer ManNAc-1P onto O-6 of the non-reducing end sugar of priming oligosaccharides, to prefer non-O-acetylated over O-acetylated primers, and to efficiently elongate the dimer of ManNAc-1-phosphate. The in vitro synthesized CPSA was purified, O-acetylated with recombinant CsaC, and proven to be identical to the natural CPSA by (1)H NMR, (31)P NMR, and immunoblotting. If all three enzymes and their substrates were combined in a one-pot reaction, nature identical CPSA was obtained. These data provide the basis for the development of novel vaccine production protocols.


Assuntos
Proteínas de Bactérias/metabolismo , Vacinas Meningocócicas , Neisseria meningitidis Sorogrupo A/enzimologia , Polissacarídeos Bacterianos/biossíntese , Cápsulas Bacterianas/enzimologia , Cápsulas Bacterianas/genética , Proteínas de Bactérias/genética , Clonagem Molecular , Humanos , Neisseria meningitidis Sorogrupo A/genética , Polissacarídeos Bacterianos/genética
5.
Oecologia ; 127(4): 468-475, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-28547483

RESUMO

Stem water content, ice fraction, and losses in xylem conductivity were monitored from November 1996 to October 1997 in an even-aged stand of Pinus contorta (lodgepole pine) near Potlatch, Idaho, USA. A time domain reflectometry (TDR) probe was used to continuously monitor stem water contents and ice fractions. Stem sapwood water contents measured with TDR were not different from water contents measured gravimetrically. The liquid water content of stems ranged from 0.70 m3 m-3 to 0.20 m3 m-3 associated with freezing and thawing of the wood tissue. Ice fraction of the stem varied from 0-75% during the winter suggesting liquid water was always present even at ambient temperatures below -20°C. Shoot xylem tensions decreased through the winter to a minimum of ca. -1.4 MPa in February then increased to -0.4 MPa in May. Shoot xylem tensions decreased during the growing season reaching -1.7 MPa by September. Annually, low shoot water potentials were not correlated to decreases in stem hydraulic conductivity. Xylem conductivity decreased due to cavitation through the winter and was 70% of summer values by March. Decreases in xylem conductivity were correlated to low shoot water potentials and cumulative freezing and thawing events within the xylem. Xylem conductivity increased to pre-winter values by May and no reductions in xylem conductivity were observed during the growing season.

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