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Search Results: 1 - 10 of 193885 matches for " David B Allison "
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Derrida's critique of Husserl and the philosophy of presence
Allison, David B.
Veritas , 2005,
Abstract: O autor reexamina a crítica de Derrida à fenomenologia de Husserl de forma a mostrar como a sua coerência estrutural emerge n o tanto de uma redu o a uma doutrina particular mas antes das exigências de uma concep o unitária, especificamente impostas pelas determina es epistemológicas e metafísicas da presen a. The author reexamines Derrida’s critique of Husserl’s phenomenology, so as to show how its structural coherency arises not so much from the reduction to a particular doctrine, but rather from the demands of a unitary conception, specifically from the demands imposed by the epistemological and metaphysical determinations of presence.
The Grand Challenge for Frontiers in Genetics: To Understand Past, Present, and Future
David B. Allison
Frontiers in Genetics , 2011, DOI: 10.3389/fgene.2011.00002
Frontiers in Nutritional Methodology Grand Challenge
Tapan Mehta,David B. Allison
Frontiers in Nutrition , 2014, DOI: 10.3389/fnut.2014.00006
Abstract: Nutrition has been central to the progress and well-being of mankind. Nutritional treatments and interventions, nutritional public policy and guidelines, issues related to agriculture and the food supply, nutritional genomics for individualized treatments, and other such topics remain vital areas of scientific inquiry. The foundation of progress in science is rigorous methods. Many of our methods have improved substantially over the years, yet there are always healthy calls for ever greater rigor in nutrition research [1-3]. Ongoing advancement in methodological aspects of nutrition, energetics, and obesity studies include at least three components: a) observations and measurements, b) experimental design, and c) statistical analysis and interpretation. We challenge ourselves and the field to expand the frontiers of nutritional knowledge by advancing the breadth, the rigor, and the quality of use of scientific methods in nutrition-related research. The beginnings of modern medicine and nutritional science can be dated to the early 17th century, when the old ideas of the Four Humors Theory [4] were finally being questioned. Back then it was customary to attribute any disease to one of the four body humors without careful measurements or analysis. Jean-Baptiste van Helmont was one of the first investigators who chose to take detailed measurements. Incidentally, this was the same era in which Galileo questioned old Greek ideas and developed devices such as the thermometer, which van Helmont used to measure temperatures. Sanctorius further improvised this device to develop a clinical thermometer for examining sick individuals [4]. It was also during the 17th century when medically oriented scientists focused on developing microscopes, an advancement from the glass lens that had been developed since the 13th century. The invention of the microscope was critical to advancing our understanding of general medical science, including nutritional research. Indeed, microscopes were crucial in our understanding the processes of energy production and chemical interaction and in the study of animal fluids [5]. Analogously, in modern times, advances like the Google Glass [6] may set the stage for us to develop next-generation data collection methods and protocols. Our first challenge is to advance data collection methods by using an ensemble of cutting-edge technological advances from fields such as biophysics, bioengineering, psychometrics, nanotechnology, and biomaterials [7-10]. Studies to estimate measurement errors and biases in data collection techniques will
Drugs Associated with More Suicidal Ideations Are also Associated with More Suicide Attempts
Henry T. Robertson, David B. Allison
PLOS ONE , 2009, DOI: 10.1371/journal.pone.0007312
Abstract: Context In randomized controlled trials (RCTs), some drugs, including CB1 antagonists for obesity treatment, have been shown to cause increased suicidal ideation. A key question is whether drugs that increase or are associated with increased suicidal ideations are also associated with suicidal behavior, or whether drug–induced suicidal ideations are unlinked epiphenomena that do not presage the more troubling and potentially irrevocable outcome of suicidal behavior. This is difficult to determine in RCTs because of the rarity of suicidal attempts and completions. Objective To determine whether drugs associated with more suicidal ideations are also associated with more suicide attempts in large spontaneous adverse event (AE) report databases. Methodology Generalized linear models with negative binomial distribution were fitted to Food and Drug Administration (FDA) Adverse Event (AE) Reporting System (AERS) data from 2004 to 2008. A total of 1,404,470 AEs from 832 drugs were analyzed as a function of reports of suicidal ideations; other non-suicidal adverse reactions; drug class; proportion of reports from males; and average age of subject for which AE was filed. Drug was treated as the unit of analysis, thus the statistical models effectively had 832 observations. Main Outcome Measures Reported suicide attempts and completed suicides per drug. Results 832 drugs, ranging from abacavir to zopiclone, were evaluated. The 832 drugs, as primary suspect drugs in a given adverse event, accounted for over 99.9% of recorded AERS. Suicidal ideations had a significant positive association with suicide attempts (p<.0001) and had an approximately 131-fold stronger magnitude of association than non-suicidal AERs, after adjusting for drug class, gender, and age. Conclusions In AE reports, drugs that are associated with increased suicidal ideations are also associated with increased suicidal attempts or completions. This association suggests that drug-induced suicidal ideations observed in RCTs plausibly represent harbingers that presage the more serious suicide attempts and completions and should be a cause for concern.
Inappropriate Fiddling with Statistical Analyses to Obtain a Desirable P-value: Tests to Detect its Presence in Published Literature
Gary L. Gadbury, David B. Allison
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0046363
Abstract: Much has been written regarding p-values below certain thresholds (most notably 0.05) denoting statistical significance and the tendency of such p-values to be more readily publishable in peer-reviewed journals. Intuition suggests that there may be a tendency to manipulate statistical analyses to push a “near significant p-value” to a level that is considered significant. This article presents a method for detecting the presence of such manipulation (herein called “fiddling”) in a distribution of p-values from independent studies. Simulations are used to illustrate the properties of the method. The results suggest that the method has low type I error and that power approaches acceptable levels as the number of p-values being studied approaches 1000.
A Novel Generalized Normal Distribution for Human Longevity and other Negatively Skewed Data
Henry T. Robertson, David B. Allison
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0037025
Abstract: Negatively skewed data arise occasionally in statistical practice; perhaps the most familiar example is the distribution of human longevity. Although other generalizations of the normal distribution exist, we demonstrate a new alternative that apparently fits human longevity data better. We propose an alternative approach of a normal distribution whose scale parameter is conditioned on attained age. This approach is consistent with previous findings that longevity conditioned on survival to the modal age behaves like a normal distribution. We derive such a distribution and demonstrate its accuracy in modeling human longevity data from life tables. The new distribution is characterized by 1. An intuitively straightforward genesis; 2. Closed forms for the pdf, cdf, mode, quantile, and hazard functions; and 3. Accessibility to non-statisticians, based on its close relationship to the normal distribution.
Using Crowdsourcing to Evaluate Published Scientific Literature: Methods and Example
Andrew W. Brown, David B. Allison
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0100647
Abstract: Systematically evaluating scientific literature is a time consuming endeavor that requires hours of coding and rating. Here, we describe a method to distribute these tasks across a large group through online crowdsourcing. Using Amazon's Mechanical Turk, crowdsourced workers (microworkers) completed four groups of tasks to evaluate the question, “Do nutrition-obesity studies with conclusions concordant with popular opinion receive more attention in the scientific community than do those that are discordant?” 1) Microworkers who passed a qualification test (19% passed) evaluated abstracts to determine if they were about human studies investigating nutrition and obesity. Agreement between the first two raters' conclusions was moderate (κ = 0.586), with consensus being reached in 96% of abstracts. 2) Microworkers iteratively synthesized free-text answers describing the studied foods into one coherent term. Approximately 84% of foods were agreed upon, with only 4 and 8% of ratings failing manual review in different steps. 3) Microworkers were asked to rate the perceived obesogenicity of the synthesized food terms. Over 99% of responses were complete and usable, and opinions of the microworkers qualitatively matched the authors' expert expectations (e.g., sugar-sweetened beverages were thought to cause obesity and fruits and vegetables were thought to prevent obesity). 4) Microworkers extracted citation counts for each paper through Google Scholar. Microworkers reached consensus or unanimous agreement for all successful searches. To answer the example question, data were aggregated and analyzed, and showed no significant association between popular opinion and attention the paper received as measured by Scimago Journal Rank and citation counts. Direct microworker costs totaled $221.75, (estimated cost at minimum wage: $312.61). We discuss important points to consider to ensure good quality control and appropriate pay for microworkers. With good reliability and low cost, crowdsourcing has potential to evaluate published literature in a cost-effective, quick, and reliable manner using existing, easily accessible resources.
Assortative marriages by body mass index have increased simultaneously with the obesity epidemic
Teresa A. Ajslev,David B. Allison
Frontiers in Genetics , 2012, DOI: 10.3389/fgene.2012.00125
Abstract: Background: The genetic predisposition to obesity may have contributed to the obesity epidemic through assortative mating. We investigated whether spouses were positively assorted by body mass index (BMI; = kg/m2) in late childhood, and whether changes in assorted marriage by upper BMI-percentiles occurred during the obesity epidemic. Methods: In the Copenhagen School Health Records Register (CSHRR) boys and girls with measures of BMI at age 13 years later became 37,792 spousal-pairs who married between 1945 and 2010. Trends in the spousal BMI correlations using sex-, age-, and birth cohort-specific BMI z-scores across time were investigated. Odds ratios (ORs) of marriage among spouses both with BMI z-scores >90th or >95th percentile compared with marriage among spouses ≤90th percentile were analyzed for marriages entered during the years prior to (1945–1970), and during the obesity epidemic (1971–2010). Findings: Spousal BMI correlations were around 0.05 and stayed similar across time. ORs of marriage among spouses with BMIs >90th percentile at age 13 were 1.21, 1.05–1.39, in 1945–1970, and increased to 1.63, 1.40–1.91, in 1971–2010 (p = 0.006). ORs of marriage among spouses both >95th BMI percentile were higher and increased more; from 1.39, 1.10–1.81, to 2.39, 1.85–3.09 (p = 0.004). Interpretation: Spousal correlations by pre-marital BMIs were small and stable during the past 65 years. Yet, there were assorted marriages between spouses with high BMI at age 13 years and the tendency increased alongside with the obesity epidemic which may increase the offsprings' predisposition to obesity.
A free-knot spline modeling framework for piecewise linear logistic regression in complex samples with body mass index and mortality as an example
Scott W. Keith,David B. Allison
Frontiers in Nutrition , 2014, DOI: 10.3389/fnut.2014.00016
Abstract: This paper details the design, evaluation, and implementation of a framework for detecting and modeling nonlinearity between a binary outcome and a continuous predictor variable adjusted for covariates in complex samples. The framework provides familiar-looking parameterizations of output in terms of linear slope coefficients and odds ratios. Estimation methods focus on maximum likelihood optimization of piecewise linear free-knot splines formulated as B-splines. Correctly specifying the optimal number and positions of the knots improves the model, but is marked by computational intensity and numerical instability. Our inference methods utilize both parametric and nonparametric bootstrapping. Unlike other nonlinear modeling packages, this framework is designed to incorporate multistage survey sample designs common to nationally representative datasets. We illustrate the approach and evaluate its performance in specifying the correct number of knots under various conditions with an example using body mass index (BMI; kg/m2) and the complex multi-stage sampling design from the Third National Health and Nutrition Examination Survey to simulate binary mortality outcomes data having realistic nonlinear sample-weighted risk associations with BMI. BMI and mortality data provide a particularly apt example and area of application since BMI is commonly recorded in large health surveys with complex designs, often categorized for modeling, and nonlinearly related to mortality. When complex sample design considerations were ignored, our method was generally similar to or more accurate than two common model selection procedures, Schwarz’s Bayesian Information Criterion (BIC) and Akaike’s Information Criterion (AIC), in terms of correctly selecting the correct number of knots. Our approach provided accurate knot selections when complex sampling weights were incorporated, while AIC and BIC were not effective under these conditions.
β2-Agonists Inhibit TNF-α-Induced ICAM-1 Expression in Human Airway Parasympathetic Neurons
Zhenying Nie, Allison D. Fryer, David B. Jacoby
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0044780
Abstract: Background Major basic protein released from eosinophils to airway parasympathetic nerves blocks inhibitory M2 muscarinic receptors on the parasympathetic nerves, increasing acetylcholine release and potentiating reflex bronchoconstriction. Recruitment of eosinophils to airway parasympathetic neurons requires neural expression of both intercellular adhesion molecular-1 (ICAM-1) and eotaxin. We have shown that inflammatory cytokines induce eotaxin and ICAM-1 expression in parasympathetic neurons. Objective To test whether the β2 agonist albuterol, which is used to treat asthma, changes TNF-alpha-induced eotaxin and ICAM-1 expression in human parasympathetic neurons. Methods Parasympathetic neurons were isolated from human tracheas and grown in serum-free medium for one week. Cells were incubated with either (R)-albuterol (the active isomer), (S)-albuterol (the inactive isomer) or (R,S)-albuterol for 90 minutes before adding 2 ng/ml TNF-alpha for another 4 hours (for mRNA) or 24 hours (for protein). Results and Conclusions Baseline expression of eotaxin and ICAM-1 were not changed by any isomer of albuterol as measured by real time RT-PCR. TNF-alpha induced ICAM-1 expression was significantly inhibited by (R)-albuterol in a dose dependent manner, but not by (S) or (R,S)-albuterol. Eotaxin expression was not changed by TNF-alpha or by any isomer of albuterol. The β-receptor antagonist propranolol blocked the inhibitory effect of (R)-albuterol on TNF-alpha-induced ICAM-1 expression. Clinical Implication The suppressive effect of (R)-albuterol on neural ICAM-1 expression may be an additional mechanism for decreasing bronchoconstriction, since it would decrease eosinophil recruitment to the airway nerves.
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