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Search Results: 1 - 10 of 4822 matches for " Roger Perkins "
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Pitfall of genome-wide association studies: Sources of inconsistency in genotypes and their effects  [PDF]
Huixiao Hong, Lei Xu, Zhenqiang Su, Jie Liu, Weigong Ge, Jie Shen, Hong Fang, Roger Perkins, Leming Shi, Weida Tong
Journal of Biomedical Science and Engineering (JBiSE) , 2012, DOI: 10.4236/jbise.2012.510069
Abstract: Personalized medicine will improve heath outcomes and patient satisfaction. However, implementing personalized medicine based on individuals’ biological information is far from simple, requiring genetic biomarkers that are mainly developed and used by the pharmaceutical companies for selecting those patients who benefit more, or have less risk of adverse drug reactions, from a particular drug. Genome-wide Association Studies (GWAS) aim to identify genetic variants across the human genome that might be utilized as genetic biomarkers for diagnosis and prognosis. During the last several years, high-density genotyping SNP arrays have facilitated GWAS that successfully identified common genetic variants associated with a variety of phenotypes. However, each of the identified genetic variants only explains a very small fraction of the underlying genetic contribution to the studied phenotypic trait. The replication studies demonstrated that only a small portion of associated loci in the initial GWAS can be replicated, even within the same populations. Given the complexity of GWAS, multiple sources of Type I (false positive) and Type II (false negative) errors exist. The inconsistency in genotypes that caused either by the genotypeing experiment or by genotype calling process is a major source of the false GWAS findings. Accurate and reproducible genotypes are paramount as inconsistency in genotypes can lead to an inflation of false associations. This article will review the sources of inconsistency in genotypes and discuss its effect in GWAS findings.
Birthday Inequalities, Repulsion, and Hard Spheres
Will Perkins
Mathematics , 2015,
Abstract: We study a birthday inequality in random geometric graphs: the probability of the empty graph is upper bounded by the product of the probabilities that each edge is absent. We show the birthday inequality holds at low densities, but does not hold in general. We give three different applications of the birthday inequality in statistical physics and combinatorics: we prove lower bounds on the free energy of the hard sphere model and upper bounds on the number of independent sets and matchings of a given size in d-regular graphs. The birthday inequality is implied by a repulsion inequality: the expected volume of the union of spheres of radius r around n randomly placed centers increases if we condition on the event that the centers are at pairwise distance greater than r. Surprisingly we show that the repulsion inequality is not true in general, and in particular that it fails in 24-dimensional Euclidean space: conditioning on the pairwise repulsion of centers of 24-dimensional spheres can decrease the expected volume of their union.
Random k-SAT and the Power of Two Choices
Will Perkins
Computer Science , 2012,
Abstract: We study an Achlioptas-process version of the random k-SAT process: a bounded number of k-clauses are drawn uniformly at random at each step, and exactly one added to the growing formula according to a particular rule. We prove the existence of a rule that shifts the satisfiability threshold. This extends a well-studied area of probabilistic combinatorics (Achlioptas processes) to random CSP's. In particular, while a rule to delay the 2-SAT threshold was known previously, this is the first proof of a rule to shift the threshold of k-SAT for k >= 3. We then propose a gap decision problem based upon this semi-random model. The aim of the problem is to investigate the hardness of the random k-SAT decision problem, as opposed to the problem of finding an assignment or certificate of unsatisfiability. Finally, we discuss connections to the study of Achlioptas random graph processes.
Biodegradation of Dispersed Oil in Arctic Seawater at -1°C
Kelly M. McFarlin, Roger C. Prince, Robert Perkins, Mary Beth Leigh
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0084297
Abstract: As offshore oil and gas exploration expands in the Arctic, it is important to expand the scientific understanding of arctic ecology and environmental impact to mitigate operational risks. Understanding the fate of oil in arctic seawater is a key factor for consideration. Here we report the chemical loss due to the biodegradation of Alaska North Slope (ANS) crude oil that would occur in the water column following the successful dispersion of a surface oil slick. Primary biodegradation and mineralization were measured in mesocosms containing Arctic seawater collected from the Chukchi Sea, Alaska, incubated at ?1°C. Indigenous microorganisms degraded both fresh and weathered oil, in both the presence and absence of Corexit 9500, with oil losses ranging from 46?61% and up to 11% mineralization over 60 days. When tested alone, 14% of 50 ppm Corexit 9500 was mineralized within 60 days. Our study reveals that microorganisms indigenous to Arctic seawater are capable of performing extensive biodegradation of chemically and physically dispersed oil at an environmentally relevant temperature (?1°C) without any additional nutrients.
The Antiparticles of Neutral Bosons  [PDF]
W. A. Perkins
Journal of Modern Physics (JMP) , 2013, DOI: 10.4236/jmp.2013.412A1003

With the advent of the ability to create and study antihydrogen, we think it is appropriate to consider the possibility that antiphotons might not be identical to photons. First of all, we will look at the experimental evidence concerning multiple neutral pions and multiple photons. Because of its internal structure, the neutral kaon is not identical to its antiparticle. We will consider internal structures for the neutral pion and photon for which the antiparticle differs from the particle. Interestingly, the antiphoton thus created from neutrinos does not interact with electrons because its neutrinos have the wrong helicity.

Composite Photon Theory versus Elementary Photon Theory  [PDF]
Walton A. Perkins
Journal of Modern Physics (JMP) , 2014, DOI: 10.4236/jmp.2014.518205
Abstract: The purpose of this paper is to show that the composite photon theory measures up well against the Standard Model’s elementary photon theory. This is done by comparing the two theories, area by area. Although the predictions of quantum electrodynamics are in excellent agreement with experiment (as in the anomalous magnetic moment of the electron), there are some problems, such as the difficulty in describing the electromagnetic field with the four-component vector potential because the photon has only two polarization states. In most areas the two theories give similar results, so it is impossible to rule out the composite photon theory. Pryce’s arguments in 1938 against a composite photon theory are shown to be invalid or irrelevant. Recently, it has been realized that in the composite theory the antiphoton does not interact with matter because it is formed of a neutrino and an antineutrino with the wrong helicity. This leads to experimental tests that can determine which theory is correct.
Black Community College Students and Opinions and Beliefs on Weight in the Community: A Focus Group Study  [PDF]
Janna Stephens, Antoinette Perkins
Health (Health) , 2019, DOI: 10.4236/health.2019.111007
Abstract: Objective: The purpose of this study was to better understand black community college students’ beliefs on obesity in their community. Methods: Participants were 18 - 21 years old and African American/Hispanic Black. Focus group sessions were conducted with a discussion guide. Thematic analysis was used to analyze results. Results: Five focus groups were conducted. Four major themes emerged: My Culture Matters, The Effects of Slavery are Still Present, Meet Me Where I Want to Be, Not Where Society Wants Me, and If They Have Been Fat, They Get Me. It is clear that weight programs need to be sensitive to cultural preferences. Conclusion: Our results present unique factors related to overweight/obesity in the Black community.
Factors Underpinning at Least Three Years of Participant Adherence to a Community-Focused Modified Boxing Program  [PDF]
Paul Perkins, Allan Hahn
Open Journal of Social Sciences (JSS) , 2019, DOI: 10.4236/jss.2019.72023
Abstract: In Australia, a modified form of boxing aimed at maximising participant safety and enjoyment has existed since 2006. Known as Box’Tag, it precludes impacts to the head and neck, in accordance with recommendations of medical and other experts. It also makes use of automated scoring technology. From 2012-2016, a Box’Tag program was run at a Police Community Youth Club (PCYC) in Canberra, Australia, with the first author of this paper as the coach. It rapidly grew to include more than 100 regular participants, which was ten times the number involved in a conventional boxing program that it replaced. During its term, it gradually evolved to increasingly take on characteristics that seemed to be valued by participants. Upon its closure, participants were asked to complete a Program Evaluation Form as part of standard PCYC procedure. Among participants who met this request, there were 38 (18 F, 20 M) who had been involved in the program for at least three years. We subsequently carried out thematic analysis of their written feedback to identify which aspects of the program had attracted them and were primarily responsible for their prolonged participation. Four major themes emerged, covering the program environment, the underlying concept, the timetable and the characteristics and outcomes of the training itself. Specifically, the environment was considered friendly, welcoming and supportive. The concept was seen to have extended beyond a sport program to encompass the establishment of a dynamic community brought together by a common interest. The program timetable was regarded as accommodating and flexible, and the training itself was described as safe, fun and beneficial in multiple respects. Overall, the participants expressed deep affection for the program. Our findings accord with those of other researchers who have sought to discern factors influencing adherence to sport and exercise programs and who now suggest that traditional, highly instructional approaches to the operation of such programs might contribute to participant dropout. Prolonged involvement in the Canberra PCYC Box’Tag program is explicable in terms of self-determination theory, in that the program seems to have provided conditions that supported participant growth in autonomy, competence and relatedness. A strong case exists for replication of these conditions in other settings.
Critical role of bioinformatics in translating huge amounts of next-generation sequencing data into personalized medicine
HuiXiao Hong,WenQian Zhang,Jie Shen,ZhenQiang Su,BaiTang Ning,Tao Han,Roger Perkins,LeMing Shi,WeiDa Tong
Science China Life Sciences , 2013, DOI: 10.1007/s11427-013-4439-7
Abstract: Realizing personalized medicine requires integrating diverse data types with bioinformatics. The most vital data are genomic information for individuals that are from advanced next-generation sequencing (NGS) technologies at present. The technologies continue to advance in terms of both decreasing cost and sequencing speed with concomitant increase in the amount and complexity of the data. The prodigious data together with the requisite computational pipelines for data analysis and interpretation are stressors to IT infrastructure and the scientists conducting the work alike. Bioinformatics is increasingly becoming the rate-limiting step with numerous challenges to be overcome for translating NGS data for personalized medicine. We review some key bioinformatics tasks, issues, and challenges in contexts of IT requirements, data quality, analysis tools and pipelines, and validation of biomarkers.
La temporalidad como estructura de L'Action (1893) de Maurice Blondel
T?3picos , 2010,
Abstract: this paper aims to offer an analysis of the estructure of maurice blondel's l'action (1893) in three different levels taking into account as a model the triadic configuration of temporality. the first level is implicit in the analysis of action made in the introduction to the work; the second level consists in the analysis of passivity described in the first moment of the fourth part; the third level contains the whole work in its global sense, extending itself to the phenomenon of action, the argument about the only necessary being and the alternative of action. i pretend to prove that the past, present and for-coming dimensions of temporality are at the base of the comprehension of this work.
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