1,406 research outputs found
Cooperative action in eukaryotic gene regulation: physical properties of a viral example
The Epstein-Barr virus (EBV) infects more than 90% of the human population,
and is the cause of several both serious and mild diseases. It is a
tumorivirus, and has been widely studied as a model system for gene
(de)regulation in human. A central feature of the EBV life cycle is its ability
to persist in human B cells in states denoted latency I, II and III. In latency
III the host cell is driven to cell proliferation and hence expansion of the
viral population, but does not enter the lytic pathway, and no new virions are
produced, while the latency I state is almost completely dormant. In this paper
we study a physico-chemical model of the switch between latency I and latency
III in EBV. We show that the unusually large number of binding sites of two
competing transcription factors, one viral and one from the host, serves to
make the switch sharper (higher Hill coefficient), either by cooperative
binding between molecules of the same species when they bind, or by competition
between the two species if there is sufficient steric hindrance.Comment: 7 pages, 6 figures, 1 tabl
Health and economic benefits of public financing of epilepsy treatment in India : an agent-based simulation model
OBJECTIVE: An estimated 6-10 million people in India live with active epilepsy, and less than half are treated. We analyze the health and economic benefits of three scenarios of publicly financed national epilepsy programs that provide: (1) first-line antiepilepsy drugs (AEDs), (2) first- and second-line AEDs, and (3) first- and second-line AEDs and surgery. METHODS: We model the prevalence and distribution of epilepsy in India using IndiaSim, an agent-based, simulation model of the Indian population. Agents in the model are disease-free or in one of three disease states: untreated with seizures, treated with seizures, and treated without seizures. Outcome measures include the proportion of the population that has epilepsy and is untreated, disability-adjusted life years (DALYs) averted, and cost per DALY averted. Economic benefit measures estimated include out-of-pocket (OOP) expenditure averted and money-metric value of insurance. RESULTS: All three scenarios represent a cost-effective use of resources and would avert 800,000-1 million DALYs per year in India relative to the current scenario. However, especially in poor regions and populations, scenario 1 (which publicly finances only first-line therapy) does not decrease the OOP expenditure or provide financial risk protection if we include care-seeking costs. The OOP expenditure averted increases from scenarios 1 through 3, and the money-metric value of insurance follows a similar trend between scenarios and typically decreases with wealth. In the first 10 years of scenarios 2 and 3, households avert on average over US$80 million per year in medical expenditure. SIGNIFICANCE: Expanding and publicly financing epilepsy treatment in India averts substantial disease burden. A universal public finance policy that covers only first-line AEDs may not provide significant financial risk protection. Covering costs for both first- and second-line therapy and other medical costs alleviates the financial burden from epilepsy and is cost-effective across wealth quintiles and in all Indian states
Parity Violation in Elastic Electron-Proton Scattering and the Proton's Strange Magnetic Form Factor
We report a new measurement of the parity-violating asymmetry in elastic electron scattering from the proton at backward scattering angles. This asymmetry is sensitive to the strange magnetic form factor of the proton as well as electroweak axial radiative corrections. The new measurement of A = -4.92±0.61±0.73 ppm provides a significant constraint on these quantities. The implications for the strange magnetic form factor are discussed in the context of theoretical estimates for the axial corrections
In Defense of the Epistemic Imperative
Sample (2015) argues that scientists ought not to believe that their theories are true because they cannot fulfill the epistemic obligation to take the diachronic perspective on their theories. I reply that Sample’s argument imposes an inordinately heavy epistemic obligation on scientists, and that it spells doom not only for scientific theories but also for observational beliefs and philosophical ideas that Samples endorses. I also delineate what I take to be a reasonable epistemic obligation for scientists. In sum, philosophers ought to impose on scientists only an epistemic standard that they are willing to impose on themselves
Parity-violating Electron Deuteron Scattering and the Proton's Neutral Weak Axial Vector Form Factor
We report on a new measurement of the parity-violating asymmetry in
quasielastic electron scattering from the deuteron at backward angles at Q2=
0.038 (GeV/c)2. This quantity provides a determination of the neutral weak
axial vector form factor of the nucleon, which can potentially receive large
electroweak corrections. The measured asymmetry A=-3.51 +/- 0.57(stat) +/-
0.58(sys)ppm is consistent with theoretical predictions. We also report on
updated results of the previous experiment at Q2=0.091 (GeV/c)2, which are also
consistent with theoretical predictions.Comment: 4 pages, 2 figures, submitted to Phys. Rev. Let
Isospin breaking in the vector current of the nucleon
Extraction of the nucleon's strange form factors from experimental data
requires a quantitative understanding of the unavoidable contamination from
isospin violation. A number of authors have addressed this issue during the
past decade, and their work is reviewed here. The predictions from early models
are largely consistent with recent results that rely as much as possible on
input from QCD symmetries and related experimental data. The resulting bounds
on isospin violation are sufficiently precise to be of value to on-going
experimental and theoretical studies of the nucleon's strange form factors.Comment: 5 pages, 3 figures. Presented at the International Workshop "From
  Parity Violation to Hadronic Structure and more...", Milos, Greece, 16-20 May
  2006. Version 2 is only to update Refs. [21] and [25
Information literacy : a critical discourse analysis of definitions in library and information science undergraduate education in the United States /
In early 2015, the Association of College and Research Libraries (ACRL, a division of the American Library Association (ALA) released the final version of the Framework for Information Literacy for Higher Education (Framework). With the Framework, the ACRL sought to conciliate and address long-standing contentions of varying conceptualizations of information literacy (IL) based on the Information Literacy Competency Standards for Higher Education (Standards) which had been critiqued since its adoption in 2000. The purpose of this work is to explore the existence of, in the context of Library and Information Sciences (LIS) undergraduate education in the United States, differences in definitions of information literacy (IL) by academic librarians, scholars, and the ACRL. Differing definitions in LIS by these three groups hold significant importance, not the least for pedagogy, practice, and the IL skills of undergraduate students.Dr. John Budd, Dissertation Supervisor.|Dr. Jenny Bossaller, Dissertation Supervisor.|Includes vita.Includes bibliographical references
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