1,441 research outputs found
THEMATIC ANALYSIS FOR THE LOSS OF ENHANCED IMAGING CAPABILITIES ON COAST GUARD MH-65 SEARCH AND RESCUE ASSETS
This study answers the following research questions: what policies and procedures within United States Coast Guard Acquisitions, as well as external factors, may have contributed to the failed sustainment of the Electro-Optical Sensor System (ESS) and the critical capability it provides? And what process changes could be implemented to prevent similar capability loss? This thematic case analysis explores how the ESS was lost and what acquisition-related decisions and processes ultimately contributed to the removal of the ESS without a viable replacement in hand. It also provides a quantitative analysis of the impact the removal of the ESS had on Coast Guard search and rescue operations. Our findings suggest that the loss of the ESS on the MH-65 was a consequence of the segregation of responsibilities between the program’s acquisitions and its sustainment resulting in the system being overlooked and the Coast Guard being caught unprepared by the end-of-life notification from Teledyne/FLIR in 2019. This analysis results in initial insights, recommendations, and potential acquisition policy improvements that can be applied to enhance the Coast Guard’s ability to sustain key aviation capabilities long-term and prevent similar scenarios in the future.Distribution Statement A. Approved for public release: Distribution is unlimited.Lieutenant Commander, United States Coast GuardLieutenant Commander, United States Coast GuardEnsign, United States Nav
Fishery dynamics of the California market squid (Loligo opalescens), as measured by satellite remote sensing
Novel data on the spatial and temporal distribution of fishing effort and population abundance are presented for the market squid fishery (Loligo opalescens) in the Southern California Bight, 1992−2000. Fishing effort was measured by the detection of boat lights by the Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS). Visual confirmation of fishing vessels by nocturnal aerial surveys indicated that lights detected by satellites are reliable indicators of fishing effort. Overall, fishing activity was concentrated off the following Channel Islands: Santa Rosa, Santa Cruz, Anacapa, and Santa Catalina. Fishing activity occurred at depths of 100 m or less. Landings, effort, and squid abundance (measured as landings per unit of effort, LPUE) markedly declined during the 1997−98 El Niño; landings and LPUE increased afterwards. Within a fishing season, the location of fishing activity shifted from the northern shores of Santa Rosa and Santa Cruz Islands in October, the typical starting date for squid fishing in the Bight, to the southern shores by March, the typical end of the squid season. Light detection by satellites offers a source of fine-scale spatial and temporal data on fishing effort for the market squid fishery off California, and these data can be integrated with environmental data and fishing logbook data in the development of a management plan
Using evidence-informed logic models to bridge methods in educational evaluation
Designs combining different types of data are increasingly used in educational evaluation, to provide both evidence of impact and an explanation of the processes by which impacts are created. Logic models are visual representations of how an intervention leads via a set of steps from resources and inputs to outputs and then sets of outcomes. Their use has become widespread to underpin evaluations; and they have become of more interest in education as they have been promoted by policy makers and funders including the Education Endowment Foundation (EEF) in England. This paper addresses the question: how can logic models be used to frame and implement educational evaluations using combinations of methods? To do so, the paper draws on theory-based evaluation literature to identify a set of issues to be considered: the role of implementation logic; causal mechanisms; the context of interventions; and the importance of considering and addressing issues around complexity. Using detailed examples from two study designs for EEF evaluations, the paper presents an evidence-informed logic model approach to deal with these issues. The paper concludes by reflecting on the practical and theoretical implications of this approach, laying out a set of key issues to address in future evaluations for which a design framed by an evidence-informed logic model may be appropriate
Active Tension Network model suggests an exotic mechanical state realized in epithelial tissues.
Mechanical interactions play a crucial role in epithelial morphogenesis, yet understanding the complex mechanisms through which stress and deformation affect cell behavior remains an open problem. Here we formulate and analyze the Active Tension Network (ATN) model, which assumes that the mechanical balance of cells within a tissue is dominated by cortical tension and introduces tension-dependent active remodeling of the cortex. We find that ATNs exhibit unusual mechanical properties. Specifically, an ATN behaves as a fluid at short times, but at long times supports external tension like a solid. Furthermore, an ATN has an extensively degenerate equilibrium mechanical state associated with a discrete conformal - "isogonal" - deformation of cells. The ATN model predicts a constraint on equilibrium cell geometries, which we demonstrate to approximately hold in certain epithelial tissues. We further show that isogonal modes are observed in the fruit y embryo, accounting for the striking variability of apical areas of ventral cells and helping understand the early phase of gastrulation. Living matter realizes new and exotic mechanical states, the study of which helps to understand biological phenomena
Scientific Opportunities with an X-ray Free-Electron Laser Oscillator
An X-ray free-electron laser oscillator (XFELO) is a new type of hard X-ray
source that would produce fully coherent pulses with meV bandwidth and stable
intensity. The XFELO complements existing sources based on self-amplified
spontaneous emission (SASE) from high-gain X-ray free-electron lasers (XFEL)
that produce ultra-short pulses with broad-band chaotic spectra. This report is
based on discussions of scientific opportunities enabled by an XFELO during a
workshop held at SLAC on June 29 - July 1, 2016Comment: 21 pages, 12 figure
Illness perceptions and explanatory models of viral hepatitis B & C among immigrants and refugees: a narrative systematic review.
© 2015 Owiti et al.; licensee BioMed Central. This is an Open Access article distributed under the terms of the Creative
Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and
reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain
Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article,
unless otherwise stated.BACKGROUND: Hepatitis B and C (HBV, HCV) infections are associated with high morbidity and mortality. Many countries with traditionally low prevalence (such as UK) are now planning interventions (screening, vaccination, and treatment) of high-risk immigrants from countries with high prevalence. This review aimed to synthesise the evidence on immigrants' knowledge of HBV and HCV that might influence the uptake of clinical interventions. The review was also used to inform the design and successful delivery of a randomised controlled trial of targeted screening and treatment. METHODS: Five databases (PubMed, CINHAL, SOCIOFILE, PsycINFO & Web of Science) were systematically searched, supplemented by reference tracking, searches of selected journals, and of relevant websites. We aimed to identify qualitative and quantitative studies that investigated knowledge of HBV and HCV among immigrants from high endemic areas to low endemic areas. Evidence, extracted according to a conceptual framework of Kleinman's explanatory model, was subjected to narrative synthesis. We adapted the PEN-3 model to categorise and analyse themes, and recommend strategies for interventions to influence help-seeking behaviour. RESULTS: We identified 51 publications including quantitative (n = 39), qualitative (n = 11), and mixed methods (n = 1) designs. Most of the quantitative studies included small samples and had heterogeneous methods and outcomes. The studies mainly concentrated on hepatitis B and ethnic groups of South East Asian immigrants residing in USA, Canada, and Australia. Many immigrants lacked adequate knowledge of aetiology, symptoms, transmission risk factors, prevention strategies, and treatment, of hepatitis HBV and HCV. Ethnicity, gender, better education, higher income, and English proficiency influenced variations in levels and forms of knowledge. CONCLUSION: Immigrants are vulnerable to HBV and HCV, and risk life-threatening complications from these infections because of poor knowledge and help-seeking behaviour. Primary studies in this area are extremely diverse and of variable quality precluding meta-analysis. Further research is needed outside North America and Australia
Nonequilibrium Weak Processes in Kaon Condensation II - Kinetics of condensation ---
The kinetics of negatively charged kaon condensation in the early stages of a
newly born neutron star is considered. The thermal kaon process, in which kaons
are thermally produced by nucleon-nucleon collisions, is found to be dominant
throughout the equilibration process. Temporal changes of the order parameter
of the condensate and the number densities of the chemical species are obtained
from the rate equations, which include the thermal kaon reactions as well as
the kaon-induced Urca and the modified Urca reactions. It is shown that the
dynamical evolution of the condensate is characterized by three stages: the
first, prior to establishment of a condensate, the second, during the growth
and subsequent saturation of the condensate, and the third, near chemical
equilibrium. The connection between the existence of a soft kaon mode and the
instability of the noncondensed state is discussed. Implications of the
nonequilibrium process on the possible delayed collapse of a protoneutron star
are also mentioned.Comment: 27 pages, incl. 8 eps figures, RevTe
Technical knowledge and water resources management: A comparative study of river basin councils, Brazil
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94603/1/wrcr12258.pd
- …