873 research outputs found
A Brachistochrone Approach to Reconstruct the Inflaton Potential
We propose a new way to implement an inflationary prior to a cosmological
dataset that incorporates the inflationary observables at arbitrary order. This
approach employs an exponential form for the Hubble parameter without
taking the slow-roll approximation. At lowest non-trivial order, this
has the unique property that it is the solution to the brachistochrone problem
for inflation.Comment: 13 pages, 2 figures, version matches published versio
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Knowledge practices in design: The role of visual representations as 'epistemic objects'
We use a detailed study of the knowledge work around visual representations to draw attention to the multidimensional nature of `objects'. Objects are variously described in the literatures as relatively stable or in flux; as abstract or concrete; and as used within or across practices. We clarify these dimensions, drawing on and extending the literature on boundary objects, and connecting it with work on epistemic and technical objects. In particular, we highlight the epistemic role of objects, using our observations of knowledge work on an architectural design project to show how, in this setting, visual representations are characterized by a `lack' or incompleteness that precipitates unfolding. The conceptual design of a building involves a wide range of technical, social and aesthetic forms of knowledge that need to be developed and aligned. We explore how visual representations are used, and how these are meaningful to different stakeholders, eliciting their distinct contributions. As the project evolves and the drawings change, new issues and needs for knowledge work arise. These objects have an `unfolding ontology' and are constantly in flux, rather than fully formed. We discuss the implications for wider understandings of objects in organizations and for how knowledge work is achieved in practice
Implementing a Prison Medicaid Enrollment Program for Inmates with a Community Inpatient Hospitalization
In 2011, North Carolina (NC) created a program to facilitate Medicaid enrollment for state prisoners experiencing community inpatient hospitalization during their incarceration. The program, which has been described as a model for prison systems nationwide, has saved the NC prison system approximately $10 million annually in hospitalization costs and has potential to increase prisonersâ access to Medicaid benefits as they return to their communities. This study aims to describe the history of NCâs Prison-Based Medicaid Enrollment Assistance Program (PBMEAP), its structure and processes, and program personnelâs perspectives on the challenges and facilitators of program implementation. We conducted semi-structured interviews and a focus group with PBMEAP personnel including two administrative leaders, two âMedicaid Facilitators,â and ten social workers. Seven major findings emerged: 1) state legislation was required to bring the program into existence; 2) the legislation was prompted by projected cost savings; 3) program development required close collaboration between the prison system and state Medicaid office; 4) technology and data sharing played key roles in identifying inmates who previously qualified for Medicaid and would likely qualify if hospitalized; 5) a small number of new staff were sufficient to make the program scalable; 6) inmates generally cooperated in filling out Medicaid applications, and their cooperation was encouraged when social workers explained possible benefits of receiving Medicaid after release; and 7) the most prominent program challenges centered around interaction with county Departments of Social Services, which were responsible for processing applications. Our findings could be instructive to both Medicaid non-expansion and expansion states that have either implemented similar programs or are considering implementing prison Medicaid enrollment programs in the future
A P53-Independent DNA Damage Response Suppresses Oncogenic Proliferation and Genome Instability
The Mre11-Rad50-Nbs1 complex is a DNA double-strand break sensor that mediates a tumor-suppressive DNA damage response (DDR) in cells undergoing oncogenic stress, yet the mechanisms underlying this effect are poorly understood. Using a genetically inducible primary mammary epithelial cell model, we demonstrate that Mre11 suppresses proliferation and DNA damage induced by diverse oncogenic drivers through a p53-independent mechanism. Breast tumorigenesis models engineered to express a hypomorphic Mre11 allele exhibit increased levels of oncogene-induced DNA damage, R-loop accumulation, and chromosomal instability with a characteristic copy number loss phenotype. Mre11 complex dysfunction is identified in a subset of human triple-negative breast cancers and is associated with increased sensitivity to DNA-damaging therapy and inhibitors of ataxia telangiectasia and Rad3 related (ATR) and poly (ADP-ribose) polymerase (PARP). Thus, deficiencies in the Mre11-dependent DDR drive proliferation and genome instability patterns in p53-deficient breast cancers and represent an opportunity for therapeutic exploitation
Underutilization of HIV Testing Among Men with Incarceration Histories
Annual HIV testing is recommended for individuals at high risk of infection, specifically incarcerated populations. Incarcerated men carry a higher lifetime risk of acquiring HIV than the general population, yet little is known about their HIV testing behaviors. We collected Audio Computer Assisted Self Interview data for 819 men entering a state prison in North Carolina. We assessed correlates of previous HIV testing, including stigmatizing attitudes and beliefs, and explored two outcomes: (1) ever HIV tested before current incarceration, and (2) recency of last HIV test. Eighty percent had been HIV tested before; of those, 36% reported testing within the last year. Being African American, having education beyond high school, prior incarceration, and higher HIV knowledge increased odds of ever having tested. Results of this study highlight the need to expand HIV testing and education specific to incarcerated populations. Additionally, efforts should be made to monitor and encourage repeat screening
Genomic differentiation during speciation-with-gene-flow: Comparing geographic and host-related variation in divergent life history adaptation in rhagoletis pomonella
A major goal of evolutionary biology is to understand how variation within populations gets partitioned into differences between reproductively isolated species. Here, we examine the degree to which diapause life history timing, a critical adaptation promoting population divergence, explains geographic and host-related genetic variation in ancestral hawthorn and recently derived apple-infesting races of Rhagoletis pomonella. Our strategy involved combining experiments on two different aspects of diapause (initial diapause intensity and adult eclosion time) with a geographic survey of genomic variation across four sites where apple and hawthorn flies co-occur from north to south in the Midwestern USA. The results demonstrated that the majority of the genome showing significant geographic and host-related variation can be accounted for by initial diapause intensity and eclosion time. Local genomic differences between sympatric apple and hawthorn flies were subsumed within broader geographic clines; allele frequency differences within the races across the Midwest were two to three-fold greater than those between the races in sympatry. As a result, sympatric apple and hawthorn populations displayed more limited genomic clustering compared to geographic populations within the races. The findings suggest that with reduced gene flow and increased selection on diapause equivalent to that seen between geographic sites, the host races may be recognized as different genotypic entities in sympatry, and perhaps species, a hypothesis requiring future genomic analysis of related sibling species to R. pomonella to test. Our findings concerning the way selection and geography interplay could be of broad significance for many cases of earlier stages of divergence-with-gene flow, including (1) where only modest increases in geographic isolation and the strength of selection may greatly impact genetic coupling and (2) the dynamics of how spatial and temporal standing variation is extracted by selection to generate differences between new and discrete units of biodiversity
The templated growth of a chiral transition metal chalcogenide
We demonstrate that an intrinsically chiral, high Miller index surface of an achiral metal can be used to template the enantioselective growth of chiral transition metal chalcogenide films. Specifically, Cu(643)R can be used as a template for the enantioselective growth of a chiral copper telluride alloy surface. Beyond a critical alloy thickness the chiral influence of the Cu(643)R surface diminishes and an achiral surface forms. Our work demonstrates a new method of producing chiral transition metal chalcogenide surfaces, with potential applications in the study of structurally chiral topological insulators
Medicaid Enrollment among Prison Inmates in a Non-expansion State: Exploring Predisposing, Enabling, and Need Factors Related to Enrollment Pre-incarceration and Post-Release
Prison inmates suffer from a heavy burden of physical and mental health problems and have considerable need for healthcare and coverage after prison release. The Affordable Care Act may have increased Medicaid access for some of those who need coverage in Medicaid expansion states, but inmates in non-expansion states still have high need for Medicaid coverage and face unique barriers to enrollment. We sought to explore barriers and facilitators to Medicaid enrollment among prison inmates in a non-expansion state. We conducted qualitative interviews with 20 recently hospitalized male prison inmates who had been approached by a prison social worker due to probable Medicaid eligibility, as determined by the inmatesâ financial status, health, and past Medicaid enrollment. Interviews were transcribed verbatim and analyzed using a codebook with both thematic and interpretive codes. Coded interview text was then analyzed to identify predisposing, enabling, and need factors related to participantsâ Medicaid enrollment prior to prison and intentions to enroll after release. Study participantsâ median age, years incarcerated at the time of the interview, and projected remaining sentence length were 50, 4, and 2 years, respectively. Participants were categorized into three sub-groups based on their self-reported experience with Medicaid_ (1) those who never applied for Medicaid before prison (n = 6); (2) those who unsuccessfully attempted to enroll in Medicaid before prison (n = 3); and (3) those who enrolled in Medicaid before prison (n = 11). The six participants who had never applied to Medicaid before their incarceration did not hold strong attitudes about Medicaid and mostly had little need for Medicaid due to being generally healthy or having coverage available from other sources such as the Veteranâs Administration. However, one inmate who had never applied for Medicaid struggled considerably to access mental healthcare due to lapses in employer-based health coverage and attributed his incarceration to this unmet need for treatment. Three inmates with high medical need had their Medicaid applications rejected at least once pre-incarceration, resulting in periods without health coverage that led to worsening health and financial hardship for two of them. Eleven inmates with high medical need enrolled in Medicaid without difficulty prior to their incarceration, largely due to enabling factors in the form of assistance with the application by their local Department of Social Services or Social Security Administration, their mothers, medical providers, or prison personnel during a prior incarceration. Nearly all inmates acknowledged that they would need health coverage after release from prison, and more than half reported that they would need to enroll in Medicaid to gain healthcare coverage following their release. Although more population-based assessments are necessary, our findings suggest that greater assistance with Medicaid enrollment may be a key factor so that people in the criminal justice system who qualify for Medicaidâand other social safety net programsâmay gain their rightful access to these benefits. Such access may benefit not only the individuals themselves but also the communities to which they return
Constructing a virtual Tower of Babel: a case study in cross-cultural collaboration across three continents
The collaboration project described in this paper revolves around the construction of a virtual Tower of Babel in a 3D Collaborative Virtual Environment (3D CVE). It involved students across three cooperating institutions, on three different continents in different time zones. It addresses the increasing need for students to engage in international collaboration, as much of today's Information and Communication Technology work demands it. This requires cross-cultural understandings with one's co-collaborators, yet there are few opportunities for this to occur in a pedagogical setting. Therefore, this paper discusses a pedagogically-oriented case study of the use of a 3D CVE as a multi-cultural classroom, describing and discussing different phases in the cross-cultural collaborative process
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A multilevel neo-institutional analysis of infection prevention and control in English hospitals: coerced safety culture change?
Despite committed policy, regulative and professional efforts on healthcare safety, little is known about how such macro-interventions permeate organisations and shape culture over time. Informed by neo-institutional theory, we examined how inter-organisational influences shaped safety practices and inter-subjective meanings following efforts for coerced culture change. We traced macro-influences from 2000 to 2015 in infection prevention and control (IPC). Safety perceptions and meanings were inductively analysed from 130 in-depth qualitative interviews with senior- and middle-level managers from 30 English hospitals. A total of 869 institutional interventions were identified; 69% had a regulative component. In this context of forced implementation of safety practices, staff experienced inherent tensions concerning the scope of safety, their ability to be open and prioritisation of external mandates over local need. These tensions stemmed from conflicts among three co-existing institutional logics prevalent in the NHS. In response to requests for change, staff flexibly drew from a repertoire of cognitive, material and symbolic resources within and outside their organisations. They crafted 'strategies of action', guided by a situated assessment of first-hand practice experiences complementing collective evaluations of interventions such as 'pragmatic', 'sensible' and also 'legitimate'. Macro-institutional forces exerted influence either directly on individuals or indirectly by enriching the organisational cultural repertoire
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