468 research outputs found
On the All-or-Nothing Behavior of Bernoulli Group Testing
In this paper, we study the problem of non-adaptive group testing, in which
one seeks to identify which items are defective given a set of
suitably-designed tests whose outcomes indicate whether or not at least one
defective item was included in the test. The most widespread recovery criterion
seeks to exactly recover the entire defective set, and relaxed criteria such as
approximate recovery and list decoding have also been considered. In this
paper, we study the fundamental limits of group testing under the significantly
relaxed {\em weak recovery} criterion, which only seeks to identify a small
fraction (e.g., ) of the defective items. Given the near-optimality of
i.i.d.~Bernoulli testing for exact recovery in sufficiently sparse scaling
regimes, it is natural to ask whether this design additionally succeeds with
much fewer tests under weak recovery. Our main negative result shows that this
is not the case, and in fact, under i.i.d.~Bernoulli random testing in the
sufficiently sparse regime, an {\em all-or-nothing} phenomenon occurs: When the
number of tests is slightly below a threshold, weak recovery is impossible,
whereas when the number of tests is slightly above the same threshold,
high-probability exact recovery is possible. In establishing this result, we
additionally prove similar negative results under Bernoulli designs for the
weak detection problem (distinguishing between the group testing model
vs.~completely random outcomes) and the problem of identifying a single item
that is definitely defective. On the positive side, we show that all three
relaxed recovery criteria can be attained using considerably fewer tests under
suitably-chosen non-Bernoulli designs.Comment: (v2) Added section on non-i.i.d. test matrices, including optimal
approximate recovery threshold. (v3) Final version accepted to IEEE Journal
on Selected Areas in Information Theory (JSAIT
The Effect of Maternal Diet on Fetal Outcomes
Maternal diet is critical for a successful pregnancy, as well as fetal health outcomes. Recent investigations reveal that dietary fats, such as omega-3 fatty acids, serve as substrates for the biosynthesis of specialized pro-resolving lipid mediators (SPM), which have anti-inflammatory and immune-stimulating effects. However, the relationship between maternal omega-3 fatty acid intake and maternal and cord plasma SPM levels in normal weight versus obese pre-pregnancy body mass index (BMI) deliveries is unclear.
Pre-pregnancy obesity is associated with serious adverse pregnancy outcomes, including an increased risk of miscarriage, caesarean section, pre-eclampsia, and thromboembolism. Along with maternal risk, these complications lead to a four-fold increase in neonatal mortality, attributed to prematurity and macrosomia. Obesity-associated inflammation in early development, from intrauterine, peri-partum, and early childhood insults, may have lifelong impacts on the offspring. Studies are needed to identify modifiable factors in the intrauterine environment and developing fetus that can reduce inflammation and limit the negative consequences of obesity during pregnancy. Recent studies reveal certain omega-3 fatty acid derivatives actively attenuate and resolve pro-inflammatory processes. These SPMs may be key to the beneficial effects of omega-3 fatty acids. While the association between inflammation and obesity is clear, the protective mechanisms of SPMs against complicated birth in maternal-fetal health are a gap in the field. Currently, it is known that SPM production is dependent on intermediates of the omega-3 fatty acid metabolic pathway. However, it is unknown how material SPM production is related to omega-3 fatty acid intake. In recent studies, the Anderson Berry Lab has found strikingly low intakes of omega-3 fatty acids in pregnant woman. Thus, understanding the therapeutic value of omega-3 fatty acid intake and the role of SPMs in maternal-fetal outcomes addresses an unmet need. We hope to achieve two specific aims: 1) to identify the relationship between maternal omega-3 fatty acid intake and maternal and cord plasma SPM levels in normal weight pre-pregnancy BMI and obese pre-pregnancy BMI deliveries and 2) to evaluate similarities and differences in intakes, food security, and transportation security. Dr. Anderson Berry will provide review of the pathophysiology of adverse pregnancy outcomes, teach and assist in a literature search for relevant manuscripts to study, and provide quality assurance for accuracy throughout the data collection process.
Over a 10-week period, the recruitment of additional subjects to augment current samples was successfully performed. Subject recruitment required the collection of informed consent, preparation of maternal and cord blood, preparation of placental tissue samples, and administration of a validated food frequency questionnaire. Over 100 new subjects were successfully enrolled in the study in this manner. Preliminary evaluation of differences in intakes, food security, and transportation security between obese and normal weight groups was completed. Due to technical equipment challenges and timing inconsistencies in data analysis, utilization of a targeted lipidomics approach to measure SPMs and determine the association between maternal omega-3 fatty acid dietary intake and maternal and cord plasma SPMs is in progress with the mass spectroscopy coil and protocol being fine-tuned on other, less valuable samples.
In the future, we hope to employ a targeted lipidomics approach to measure SPM levels and determine the association between maternal omega-3 fatty acid dietary intake and maternal and cord plasma SPM levels at the time of delivery. We plan to analyze 80 existing samples (40 mother-infant pairs) consisting of maternal, cord, placental, and neonatal blood and breast milk, 32% of which had a pre-pregnancy BMI \u3e30. Clinical data from these subjects and dietary data measured via a validated food frequency questionnaire have been obtained. Dr. Nordgren will then determine SPM levels in plasma and placental samples via liquid chromatography-tandem mass spectrometry-mediated lipid identification. Key lipids and metabolites to be characterized will include 18- HEPE, 15-HETE, RvE1, RvD1, RvD2, RVD3, RvD5, 17(R)-RvD1, Maresin-1, and protectin-D1. This technique will also allow for determination of the association between maternal and cord serum concentrations of SPMs of obese pre-pregnancy BMI delivery. Levels and associations with clinical pregnancy outcomes will be analyzed. It is hypothesized that in the presence of obesity mediated inflammation, adequate omega-3 fatty acid intake provides a pool of substrates for increased SPM production, minimizing poor pregnancy outcomes.https://digitalcommons.unmc.edu/com_students_pres/1000/thumbnail.jp
Development of the legitimacy threshold scale
A consensus in the literature supports the premise that legitimacy attainment facilitates favorable judgments from key stakeholders regarding the acceptability, appropriateness and worthiness of entrepreneurs and their efforts in emerging ventures. However, although legitimacy attainment is a milestone that emerging ventures strive to reach, as researchers we do not yet have a measure that examines whether a firm is operating pre- versus post-legitimacy. Accordingly, we develop the legitimacy threshold scale (LTS) that will facilitate the assessment of activities performed pre- and post-legitimacy in emerging ventures
Reducing “Treble” with Performance Focused Music Programs in Medical School: A Student Driven Needs Assessment to Clarify Participation Barriers Amongst Undergraduate Medical Students
Introduction: The beneficial impact of performing arts involvement within undergraduate medical education, such as music, has been studied, but support for the arts varies significantly by institution. Research has suggested that medical student involvement in the arts can help develop their identities as physicians and may reduce stress and burnout, an increasingly difficult problem within the medical student community.
Methods: We used a mixed-method cross-sectional study design, using a questionnaire and semi-structured interview designed amongst a team of music professionals and healthcare providers with music backgrounds. Out of 511 enrolled medical students, 93 students participated in the study for a response rate of 18.2%. Questions were piloted among eight medical students, with modifications made in response to feedback. Participants were recruited to participate in an online survey via social media.
Results: Within our sample, the most popular background instrument was piano (58.5%) and voice (50.0%). Of those who responded, most preferred to perform alone (85.7%) or in small groups (51.4%). 78.8% of respondents agreed that music was essential to their wellbeing. Only 62.5% of the respondents with musical backgrounds still play music or sing. Of those who no longer play music, 90.5% of respondents reported time constraint as the limiting factor, followed by lack of access to instruments (42.9%).
Conclusion: This study suggests there are diverse music backgrounds and interests amongst the medical student population. Although most participants believed music was a form of stress relief, undergraduate medical training demands impose time restrictions on student engagement. Investments in music programs that enable adequate involvement and meet student demand have the potential to improve medical student engagement with the arts, alleviate stress, and may even lead to stronger/more empathetic physicians. Periodic needs assessments may be a powerful tool to better align programming to address student desires and reduce barriers
Web based expert elicitation of uncertainties in environmental model inputs
When constructing and using environmental models, it is typical that many of the inputs to the models will not be known perfectly. In some cases, it will be possible to make observations, or occasionally physics-based uncertainty propagation, to ascertain the uncertainty on these inputs. However, such observations are often either not available or even possible, and another approach to characterising the uncertainty on the inputs must be sought. Even when observations are available, if the analysis is being carried out within a Bayesian framework then prior distributions will have to be specified. One option for gathering or at least estimating this information is to employ expert elicitation. Expert elicitation is well studied within statistics and psychology and involves the assessment of the beliefs of a group of experts about an uncertain quantity, (for example an input / parameter within a model), typically in terms of obtaining a probability distribution. One of the challenges in expert elicitation is to minimise the biases that might enter into the judgements made by the individual experts, and then to come to a consensus decision within the group of experts. Effort is made in the elicitation exercise to prevent biases clouding the judgements through well-devised questioning schemes. It is also important that, when reaching a consensus, the experts are exposed to the knowledge of the others in the group. Within the FP7 UncertWeb project (http://www.uncertweb.org/), there is a requirement to build a Webbased tool for expert elicitation. In this paper, we discuss some of the issues of building a Web-based elicitation system - both the technological aspects and the statistical and scientific issues. In particular, we demonstrate two tools: a Web-based system for the elicitation of continuous random variables and a system designed to elicit uncertainty about categorical random variables in the setting of landcover classification uncertainty. The first of these examples is a generic tool developed to elicit uncertainty about univariate continuous random variables. It is designed to be used within an application context and extends the existing SHELF method, adding a web interface and access to metadata. The tool is developed so that it can be readily integrated with environmental models exposed as web services. The second example was developed for the TREES-3 initiative which monitors tropical landcover change through ground-truthing at confluence points. It allows experts to validate the accuracy of automated landcover classifications using site-specific imagery and local knowledge. Experts may provide uncertainty information at various levels: from a general rating of their confidence in a site validation to a numerical ranking of the possible landcover types within a segment. A key challenge in the web based setting is the design of the user interface and the method of interacting between the problem owner and the problem experts. We show the workflow of the elicitation tool, and show how we can represent the final elicited distributions and confusion matrices using UncertML, ready for integration into uncertainty enabled workflows.We also show how the metadata associated with the elicitation exercise is captured and can be referenced from the elicited result, providing crucial lineage information and thus traceability in the decision making process
Reducing Treble with Performance Focused Music Programs in Medical School: A Student Driven Needs Assessment to Clarify Participation Barriers Amongst Undergraduate Medical Students
Integration of the arts into medical education has numerous benefits, including reducing burnout and producing empathetic physicians. Investment in arts-related activities has expanded considerably. However, funding remains a common limitation for further integration of arts into medical education. Clarifying student preferences and barriers to music programs can optimize such limited resources to best suit medical student needs.https://digitalcommons.unmc.edu/emet_posters/1033/thumbnail.jp
Open Notebook Science Challenge: Solubilities of Organic Compounds in Organic Solvents
This book contains the results of the Open Notebook Science Solubility Challenge. All experimental measurements are provided with a link to either the laboratory notebook page where the experiment was carried out or to a literature reference. The Challenge was sponsored by Submeta, Nature and Sigma-Aldrich
Open Notebook Science Challenge: Solubilities of Organic Compounds in Organic Solvents
This book contains the results of the Open Notebook Science Solubility Challenge. All experimental measurements are provided with a link to either the laboratory notebook page where the experiment was carried out or to a literature reference. The Challenge was sponsored by Submeta, Nature and Sigma-Aldrich
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