678 research outputs found
Moth-inspired navigation algorithm in a turbulent odor plume from a pulsating source
Some female moths attract male moths by emitting series of pulses of
pheromone filaments propagating downwind. The turbulent nature of the wind
creates a complex flow environment, and causes the filaments to propagate in
the form of patches with varying concentration distributions. Inspired by moth
navigation capabilities, we propose a navigation strategy that enables a flier
to locate a pulsating odor source in a windy environment using a single
threshold-based detection sensor. The strategy is constructed based on the
physical properties of the turbulent flow carrying discrete puffs of odor and
does not involve learning, memory, complex decision making or statistical
methods. We suggest that in turbulent plumes from a pulsating point source, an
instantaneously measurable quantity referred as a "puff crossing time",
improves the success rate as compared to the navigation strategy based on
"internal counter" that does not use this information. Using computer
simulations of fliers navigating in turbulent plumes of the pulsating point
source for varying flow parameters: turbulent intensities, plume meandering and
wind gusts, we obtained trajectories qualitatively resembling male moths
flights towards the pheromone sources. We quantified the probability of a
successful navigation as well as the flight parameters such as the time spent
searching and the total flight time, with respect to different turbulent
intensities, meandering or gusts. The concepts learned using this model may
help to design odor-based navigation of miniature airborne autonomous vehicles
Assessing Challenges Facing Implementation of Information Security Critical Success Factors: A Case of National Examination Council, Tanzania
Aim of this study was to assess challenges facing implementation of information security critical success factors. The study employed quantitative research approach and survey research design where case study design was used. A sample of 79 respondents derived from the population sample of 372 were used by using Slovin’s formula sampling technique, 86% of respondents questionnaire filled effectively were used. Descriptive data analysis was used to analyze variables based on research questions while, statistical tables and figures were used in data presentation. Results of this study indicate that, there are challenges in implementation of information security critical success factors such as security training program, security policy, risk assessment, regular system update, system auditing and committed of top management. The study found reasons for challenges of implementation from respondent views as availability of limited resources, weak financial support from top management, lack of understanding of needed technology from information technology professionals; poor security awareness program for top management who may think that information security is the issue of information technology department only and not the whole organization. It is therefore concluded that organization should identify their specific information security critical success factors to enhance useful of organization limited resource, without investing in generalization and give solutions based on risk priority, in order to make organization secure also utilization of information security critical success factors holds significant importance in ensuring security of an organization's data. It is crucial to address and eliminate any challenges that are within the scope of affordability or manageability
Pre-operational baseline studies of selected nearshore marine biota at the Diablo Canyon power plant site: 1979-1982
This is the final report of the California Department of Fish and Games intertidal and subtidal surveys of plants and animals in the vicinity of the Diablo Canyon Power Plant. These studies cover the period from 1979 through 1982. Our previous report (Gotshall, et al. 1984) covered the period from 1973 through 1978. The report includes abundances and statistical analyses of comparisons of abundances between years and study areas for selected intertidal and subtidal plants and animals. A total of 556 random subtidal
stations, 540 intertidal stations and 67 permanent abalone transects were completed during this report period.
Trends in abundances of most species observed during our 1973 through 1978 studies continued, i.e. the population of giant red sea urchins remained at a very low level, bull kelp Nereocystis leutkeana densities continued to decline in Diablo Cove and North Control. These two trends are probably due to the effects of continued sea otter foraging in the study area.
Our observations of the presence or absence of fishes at subtidal 30m stations indicate a continued decline in the abundances of lingcod, Ophiodon elongatus and a decline in the abundance of blue rockfish since the 1973 through 1978 study period.
A new study was begun during this study period, the use of baited stations to obtain relative abundance indices for those species of fishes attracted to the bait. Black-and-yellow rockfish were the most frequently observed fishes at Diablo Cove stations, while blue rockfish were the most frequently observed fish at North control baited stations. (Document has 393 pages
A Comprehensive Overview of In-patients Treated for Hepatocellular Carcinoma at a Tertiary Care Facility in Tanzania
Hepatocellular carcinoma (HCC) is one of the commonest causes of cancer-related morbidity and mortality worldwide. However, only a limited number of studies on HCC have been conducted in Tanzania. We therefore conducted a cross-sectional study among in-patients treated for HCC in a tertiary referral hospital located in Dar es Salaam, Tanzania, in order to provide a concise description of the clinical characteristics and treatment options offered in the study setting. We identified 36 in-patients treated for HCC over a 6-month data collection period. Seventy-seven percent (n = 28) of the participants were males and about two-thirds (61.2%) were aged between 40 and 60 years. Majority (44.4% [n = 16]) of the patients had Child-Pugh class B and an Eastern Cooperative Oncology Group (ECOG) performance status of 2 (33.3% [n = 12]). Patients with tumors >6.5 cm and multinodular tumors (>3 nodules) accounted for 69.4% (n = 25) and 55.6% (n = 20), respectively. Portal vascular invasion and extrahepatic metastasis were respectively present in 27.8% (n = 10) and 25% (n = 9) of the patients. Of the study participants, only two had early-stage disease as per the Barcelona Clinic Liver Cancer (BCLC) staging system, corresponding to the observed tumor resection rate of 5.6%. The most frequently reported inoperable factor among the study participants was an ECOG performance status > 0 (n = 30 [83.3%]). Findings thus reveal a high proportion of late-stage diseases among participants that could have resulted in the observed low tumor resection rate. Initiatives to facilitate identification of the disease at an early stage are therefore paramount in optimizing care
Novel gas-driven fuel cell HVAC and dehumidification prototype
Performance of a novel gas-driven, electricity-producing heating, ventilation, and air conditioning (HVAC) system with no vapor compression and no hydrofluorocarbon (HFC) refrigerant shall be discussed in the paper. The prototype was evaluated at ORNL under a Small Business Voucher (SBV) Cooperative Research and Development (CRADA) program. The target market is commercial buildings in the United States. The goal is to mitigate or eliminate grid-power for building air conditioning, coincident peak demand and associated spinning reserves, aiding in flattening of the “duck curve”. The technical goal is to transform the common packaged rooftop unit into a cost-effective distributed energy resource, opening a new range of small applications and broad markets for micro-combined cycle cooling, heating, and power with integral thermal energy storage. The test results indicate the prototype would be competitive with natural gas distributed power plants with average electrical production ranging from 45% to 60% natural gas to electricity conversion efficiency. The technology has a Primary Energy Savings Potential of 4.4 Quads, higher than any other air conditioning and heating technology
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Epigenome-wide association study of systemic effects of obesity susceptibility in human twins
The current study was designed to use an epigenome-wide association approach (EWAS) to identify potential systemic DNA methylation alterations that are associated with obesity using 22 discordant twin pairs. Buccal cells (from a cheek swab) were used as a non-obesity relevant purified marker cell for the epigenetic analysis. Analysis of differential DNA methylation regions (DMRs) was used to identify epigenetic associations with metabolic and dietary measures related to obesity with discordant twins. An edgeR analysis provided a DMR signature with p < 1e-04, but statistical significance was reduced due to low sample size and known multiple origins of obesity. A weighted gene coexpression network analysis (WGCNA) was performed and identified modules (p < 0.005) of epigenetic sites that correlated with different metabolic and dietary measures. The DMR and WGCNA epigenetic sites were near genes (e.g., CIDEC, SPP1, ZFPG9, and POMC) with previously identified obesity associated pathways (e.g., metabolism, cholesterol, and fat digestion). Observations demonstrate the feasibility of identifying systemic epigenetic biomarkers for obesity, which can be further investigated for clinical relevance in future research with larger sample sizes. The availability of a systemic epigenetic biomarker for obesity susceptibility may facilitate preventative medicine and clinical management of the disease early in life
Epigenome-wide association study of physical activity and physiological parameters in discordant monozygotic twins
An epigenome-wide association study (EWAS) was performed on buccal cells from monozygotic-twins (MZ) reared together as children, but who live apart as adults. Cohorts of twin pairs were used to investigate associations between neighborhood walkability and objectively measured physical activity (PA) levels. Due to dramatic cellular epigenetic sex differences, male and female MZ twin pairs were analyzed separately to identify differential DNA methylation regions (DMRs). A priori comparisons were made on MZ twin pairs discordant on body mass index (BMI), PA levels, and neighborhood walkability. In addition to direct comparative analysis to identify specific DMRs, a weighted genome coexpression network analysis (WGCNA) was performed to identify DNA methylation sites associated with the physiological traits of interest. The pairs discordant in PA levels had epigenetic alterations that correlated with reduced metabolic parameters (i.e., BMI and waist circumference). The DNA methylation sites are associated with over fifty genes previously found to be specific to vigorous PA, metabolic risk factors, and sex. Combined observations demonstrate that behavioral factors, such as physical activity, appear to promote systemic epigenetic alterations that impact metabolic risk factors. The epigenetic DNA methylation sites and associated genes identified provide insight into PA impacts on metabolic parameters and the etiology of obesity
How well do LLMs cite relevant medical references? An evaluation framework and analyses
Large language models (LLMs) are currently being used to answer medical
questions across a variety of clinical domains. Recent top-performing
commercial LLMs, in particular, are also capable of citing sources to support
their responses. In this paper, we ask: do the sources that LLMs generate
actually support the claims that they make? To answer this, we propose three
contributions. First, as expert medical annotations are an expensive and
time-consuming bottleneck for scalable evaluation, we demonstrate that GPT-4 is
highly accurate in validating source relevance, agreeing 88% of the time with a
panel of medical doctors. Second, we develop an end-to-end, automated pipeline
called \textit{SourceCheckup} and use it to evaluate five top-performing LLMs
on a dataset of 1200 generated questions, totaling over 40K pairs of statements
and sources. Interestingly, we find that between ~50% to 90% of LLM responses
are not fully supported by the sources they provide. We also evaluate GPT-4
with retrieval augmented generation (RAG) and find that, even still, around
30\% of individual statements are unsupported, while nearly half of its
responses are not fully supported. Third, we open-source our curated dataset of
medical questions and expert annotations for future evaluations. Given the
rapid pace of LLM development and the potential harms of incorrect or outdated
medical information, it is crucial to also understand and quantify their
capability to produce relevant, trustworthy medical references
Typology and Dynamics of Heavier Drinking Styles in Great Britain: 1978-2010.
AIMS: To identify a typology of heavier drinking styles in Great Britain and to identify socio-demographic trends in the typology over the period 1978-2010. METHODS: We applied multiple correspondence analysis and agglomerative hierarchical clustering to beverage-specific quantity-frequency measures of alcohol consumption in the repeated cross-sectional General Lifestyle Survey of Great Britain, 1978-2010. The cluster analysis focuses on the 60,043 adult respondents over this period reporting average drinking levels above the UK Government guidelines. We projected sex, age, income, education, socio-economic status and tobacco consumption variables onto the clusters to inspect socio-demographic trends in heavier drinking. RESULTS: We identified four stable clusters of heavier drinking: (a) high volume beer; (b) beer and spirit combination; (c) all beverage and (d) wine and spirit only. The socio-demographic characteristics of the clusters were distinct from both each other and the general population. However, all clusters had higher median incomes and higher smoking rates than the population. Increases in the prevalence of heavier drinking were driven by a 5-fold increase in the contribution of the female-dominated, wine and spirit only cluster. CONCLUSIONS: Recent changes in per capita alcohol consumption in Great Britain occurred within the context of a stable typology of heavier drinking styles and shifting socio-demographics. Identifying these trends is essential to better understand how drinking cultures develop over time and where potentially problematic drinking styles may emerge. Our findings suggest that careful attention to patterns and cultures of consumption is more important than relying on headline consumption data, for both understanding drinking behaviours and targeting interventions. SHORT SUMMARY: This analysis of alcohol consumption survey data identifies four styles of heavier drinking in Great Britain, which remain unchanged over the period 1978-2010. The socio-demographic characteristics of the drinking styles are distinct from both each other and the general population, with increased participation of female and older drinkers over time
Brain function distinguishes female carriers and non-carriers of familial risk for autism
BACKGROUND: Autism spectrum disorder (ASD) is characterized by high population-level heritability and a three-to-one male-to-female ratio that occurs independent of sex linkage. Prior research in a mixed-sex pediatric sample identified neural signatures of familial risk elicited by passive viewing of point light motion displays, suggesting the possibility that both resilience and risk of autism might be associated with brain responses to biological motion. To confirm a relationship between these signatures and inherited risk of autism, we tested them in families enriched for genetic loading through undiagnosed ( carrier ) females.
METHODS: Using functional magnetic resonance imaging, we examined brain responses to passive viewing of point light displays-depicting biological versus non-biological motion-in a sample of undiagnosed adult females enriched for inherited susceptibility to ASD on the basis of affectation in their respective family pedigrees. Brain responses in carrier females were compared to responses in age-, SRS-, and IQ-matched non-carrier-females-i.e., females unrelated to individuals with ASD. We conducted a hypothesis-driven analysis focused on previously published regions of interest as well as exploratory, brain-wide analyses designed to characterize more fully the rich responses to this paradigm.
RESULTS: We observed robust responses to biological motion. Notwithstanding, the 12 regions implicated by prior research did not exhibit the hypothesized interaction between group (carriers vs. controls) and point light displays (biological vs. non-biological motion). Exploratory, brain-wide analyses identified this interaction in three novel regions. Post hoc analyses additionally revealed significant variations in the time course of brain activation in 20 regions spanning occipital and temporal cortex, indicating group differences in response to point light displays (irrespective of the nature of motion) for exploration in future studies.
LIMITATIONS: We were unable to successfully eye-track all participants, which prevented us from being able to control for potential differences in eye gaze position.
CONCLUSIONS: These methods confirmed pronounced neural signatures that differentiate brain responses to biological and scrambled motion. Our sample of undiagnosed females enriched for family genetic loading enabled discovery of numerous contrasts between carriers and non-carriers of risk of ASD that may index variations in visual attention and motion processing related to genetic susceptibility and inform our understanding of mechanisms incurred by inherited liability for ASD
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