6,624 research outputs found
Direct stimulation of the retina by the method of virtual-quanta for heavy cosmic-ray nuclei
The contribution to the frequency of visual sensations induced in the dark-adapted eye by the virtual photon field was calculated, this field is associated with the heavy nuclei that exist in space beyond the geomagnetic field. In order to determine the probability that the virtual photon field induces a light flash, only the portion of the virtual photon spectrum that corresponds to the known frequency dependence of the sensitivity of human rods to visible light was utilized. The results can be expressed as a curve of the mean frequency of light flashes induced by the absorption of at least R virtual photons versus the threshold number R. The contribution to the light flash frequency from the virtual photon field of heavy cosmic ray nuclei is smaller than that from Cerenkov photons. The flux and energy spectra of galactic cosmic ray nuclei helium to iron were used
Homeless and Hopeless: Resignation in News Media Constructions of Homelessness as a Social Problem
This dissertation examined news constructions of homelessness as a social problem to identify how news stories communicate notions of what constitutes homelessness; how many and what types of people are homeless; and who can, should or must do something about this social problem. The study entailed a narrative analysis of 92 news magazine articles and 111 CBS news broadcasts about homelessness. The dissertation included a frequency analysis of homeless-related citations appearing in Reader\u27s Guide to Periodical Literature, Television News Index and Abstracts and the Social Science Index from 1976 to 1990. News stories present no explicit definition of homelessness and use the term to describe multiple and diverse populations. Imprecise language regarding homelessness leads to variance and contradiction yet meager debate about the nature--or size--of the homeless population. News stories portray homelessness as related to or enmeshed in several other social problems and rarely clarify whether homelessness is a cause, effect or symptom of such problems. News stories thus portray homelessness as a vague, incomprehensible and intractable problem. News constructs five central images of homeless people by focusing on social actors, relationships, behaviors, conditions and causes of homelessness. Homeless people appear as institution avoiders, mentally ill individuals, families and children, runaway or abandoned teens, and threatening villains. Biographies and vignettes, journalistic commentary, visual techniques, and the presentation of numerical and research information are conventions establishing news stories as factual. Images portray unambiguous sets of victims and villains, emphasize individualistic problem causes and contribute to resignation about homelessness. The study proposes two models of communication about homelessness: a social action model presenting a problem about which someone must do something, and a hopelessness model suggesting an unchangeable problem. Overall, news stories exhibit resignation that nothing can be done to alleviate homelessness; they lack calls for action, responsibility and remedies regarding homelessness. A proposed conceptual continuum describes four levels of resignation about homelessness; each level reflects a different configuration of the two models. The study suggests directions for future research
Luminosity measurements at LHCb using dimuon pairs produced via elastic two photon fusion.
This note outlines the feasibility of using the elastic two photon process pp p+ to make luminosity measurements at LHCb. The overall efficiency at LHCb for recording and selecting pp p+ events produced within 1.6<<5 has been determined using Monte-Carlo to be 0.0587 0.0008, yielding 521071(stat.) events for an integrated luminosity of 1fb. The main background processes where dimuons are produced via inelastic two-photon fusion and double Pomeron exchange have been studied using the full LHCb detector simulation while the other background sources, including backgrounds caused by K/ mis-identification, have been studied at four vector level. The background is estimated to be (4.1 0.5(stat.) 0.6(syst.))% of the signal level. Most of this background comes from K/ mis-identification, although the largest source of uncertainty in the estimation is due to knowledge of the number of events produced via double Pomeron exchange. Systematic uncertainties on a luminosity measurement at LHCb using this channel are estimated to be ~1% the largest of which are the uncertainty on the predicted cross-section for events containing dimuons produced via double Pomeron exchange, and the knowledge of the trigger and reconstruction efficiency for muons in LHCb
Contaminant removal from enclosed atmospheres by regenerable adsorbents
A system for removing contaminants from spacecraft atmospheres was studied, which utilizes catalyst-impregnated activated carbon followed by in-situ regeneration by low-temperature catalytic oxidation of the adsorbed contaminants. Platinum was deposited on activated carbon by liquid phase impregnation with chloroplatinic acid, followed by drying and high-temperature reduction. Results were obtained for the seven selected spacecraft contaminants by means of three experimental test systems. The results indicate that the contaminants could be removed by oxidation with very little loss in adsorptive capacity. The advantages of a catalyst-impregnated carbon for oxidative regeneration are found to be significant enough to warrent its use
Evaluation of techniques for removal of spacecraft contaminants from activated carbon
Alternative techniques for the regeneration of carbon contaminated with various spacecraft contaminants were evaluated. Four different modes of regeneration were evaluated: (1) thermal desorption via vacuum, (2) thermal desorption via nitrogen purge, (3) in-situ catalytic oxidation of adsorbed contaminants, and (4) in-situ non-catalytic oxidation of adsorbed contaminants
The Efficacy of Peripheral Opioid Antagonists in Opioid-Induced Constipation and Postoperative Ileus: A Systematic Review of the Literature.
Opioid-induced constipation has a negative impact on quality of life for patients with chronic pain and can affect more than a third of patients. A related but separate entity is postoperative ileus, which is an abnormal pattern of gastrointestinal motility after surgery. Nonselective μ-opioid receptor antagonists reverse constipation and opioid-induced ileus but cross the blood-brain barrier and may reverse analgesia. Peripherally acting μ-opioid receptor antagonists target the μ-opioid receptor without reversing analgesia. Three such agents are US Food and Drug Administration approved. We reviewed the literature for randomized controlled trials that studied the efficacy of alvimopan, methylnaltrexone, and naloxegol in treating either opioid-induced constipation or postoperative ileus. Peripherally acting μ-opioid receptor antagonists may be effective in treating both opioid-induced bowel dysfunction and postoperative ileus, but definitive conclusions are not possible because of study inconsistency and the relatively low quality of evidence. Comparisons of agents are difficult because of heterogeneous end points and no head-to-head studies
Using Generative AI to Remove Barriers in Support of Open Content Creation
Open content, such as textbook-length open educational resources (OER) or smaller pieces like an assignment, can offer numerous benefits to students by being free, diverse, and effective replacements for traditional textbooks, but there are limited open resources and difficulties creating new open content. This poster explores how generative AI can remove these barriers, enabling instructors to have time and support to create and use open content in their courses. By highlighting use cases, attendees will see how to do this approach in their own classroom, regardless of modality or discipline. Important considerations will be addressed, including usage, sharing, and ethics.
This poster presentation was presented at Teaching and Learning with AI Conference 2023
The 5-Ps of Jumpstarting Open Assessment Creation with Generative AI
Generative Artificial Intelligence (AI trained on Large Language Models to generate text) has exploded into the digital learning space. As the need for Open Educational Resources (OER) also continues to grow, generative AI can jumpstart aspects of OER creation. This presentation will consider barriers to OER adoption, including the availability of supplemental teaching resources, and will propose a use case for leveraging AI text-generation to support best practices for creating unique assessment questions. Through the “5-Ps,” – Problem, Past, Present, Possibilities, and Product – we will consider the ways that adopters, adapters, and authors of OER can use generative AI to support access, innovation, and evaluation. We will consider OER adoption through the lenses of textbook affordability and instructional design to propose a framework for using generative-AI so that open education reaches more learners while maintaining the principles of research-backed assessment practices.
This is a presentation for the Open Education Conference 2023
Microdosimetry radiation analysis method and device
Apparatus and method for qualitatively and quantitatively analyzing a complex radiation field are provided. A microdosimetry device is provided having an array of microstructure parallel p-n junctions. Each junction defines a predetermined sensitive volume within which a voltage pulse is produced responsive to incident radiation. Circuitry in communication with the detector array generates digital pulse signals representative of the voltage pulses induced within the sensitive volumes responsive to incident radiation, and further provides a summation of the digital pulses occurring at particular energies. The summations of digital pulses are compared to known energies generated by known ionizing particles in comparable sensitive volumes to generate an dose equivalent estimate. Apparatus and method for calculating the total dose from an incident radiation field may also be included
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