5,083 research outputs found
Unkindest cuts: reflections on destruction and resilience in LGBTQ community-based mental health support
This article reflects on the closure of specialist community-based LGBTQ mental health support from the perspective of people who have used or work in such services. The authors discuss the need for community-based specialist support for LGBTQ people who experience mental health problems or work in mental health services
Seismic data reveal eastern Black Sea Basin structure
Rifted continental margins are formed by progressive extension of the lithosphere. The development of these margins plays an integral role in the plate tectonic cycle, and an understanding of the extensional process underpins much hydrocarbon exploration. A key issue is whether the lithosphere extends uniformly, or whether extension varies\ud
with depth. Crustal extension may be determined using seismic techniques. Lithospheric extension may be inferred from the waterloaded subsidence history, determined from\ud
the pattern of sedimentation during and after rifting. Unfortunately, however, many rifted margins are sediment-starved, so the subsidence history is poorly known.\ud
To test whether extension varies between the crust and the mantle, a major seismic experiment was conducted in FebruaryâMarch 2005 in the eastern Black Sea Basin (Figure 1), a deep basin where the subsidence history is recorded\ud
by a thick, post-rift sedimentary sequence. The seismic data from the experiment indicate the presence of a thick, low-velocity zone, possibly representing overpressured sediments. They also indicate that the basement and\ud
Moho in the center of the basin are both several kilometers shallower than previously inferred. These initial observations may have considerable impact on thermal models of the petroleum system in the basin. Understanding\ud
the thermal history of potential source rocks is key to reducing hydrocarbon exploration risk. The experiment, which involved collaboration between university groups in the United Kingdom, Ireland, and Turkey, and BP and\ud
Turkish Petroleum (TPAO), formed part of a larger project that also is using deep seismic reflection and other geophysical data held by the industry partners to determine the subsidence history and hence the strain evolution of\ud
the basin
A review of functional outcomes and union rates in patients with lateral clavicular fractures treated with hook plate fixation
Power Spectra for Cold Dark Matter and its Variants
The bulk of recent cosmological research has focused on the adiabatic cold
dark matter model and its simple extensions. Here we present an accurate
fitting formula that describes the matter transfer functions of all common
variants, including mixed dark matter models. The result is a function of
wavenumber, time, and six cosmological parameters: the massive neutrino
density, number of neutrino species degenerate in mass, baryon density, Hubble
constant, cosmological constant, and spatial curvature. We show how
observational constraints---e.g. the shape of the power spectrum, the abundance
of clusters and damped Lyman-alpha systems, and the properties of the
Lyman-alpha forest--- can be extended to a wide range of cosmologies, including
variations in the neutrino and baryon fractions in both high-density and
low-density universes.Comment: 20 pages, LaTeX, 4 figures. Submitted to ApJ. Electronic versions of
the fitting formula, as well as simple codes to output cosmological
quantities (e.g. sigma_8) as a function of parameters and illustrative
animations of parameter dependence, are available at
http://www.sns.ias.edu/~whu/transfer/transfer.htm
Friedel oscillations in a two-band Hubbard model for CuO chains
Friedel oscillations induced by open boundary conditions in a two-band
Hubbard model for CuO chains are numerically studied. We find that for
physically realistic parameters and close to quarter filling, these
oscillations have a 2k_F modulation according with experimental results on
YBa_2Cu_3O_{7-delta}. In addition, we predict that, for the same parameters, as
hole doping is reduced from quarter filling to half filling, Friedel
oscillations would acquire a 4k_F modulation, typical of a strongly correlated
electrons regime. The 4k_F modulation dominates also in the electron doped
region. The range of parameters varied is very broad, and hence the results
reported could apply to other cuprates and other strongly correlated compounds
with quasi-one dimensional structures. On a more theoretical side, we stress
the fact that the copper and oxygen subsystems should be described by two
different Luttinger liquid exponents.Comment: 7 pages, 7 eps figure
Adaptive LĂŠvy processes and area-restricted search in human foraging
A considerable amount of research has claimed that animalsâ foraging behaviors display movement lengths with power-law distributed tails, characteristic of LĂŠvy flights and LĂŠvy walks. Though these claims have recently come into question, the proposal that many animals forage using LĂŠvy processes nonetheless remains. A LĂŠvy process does not consider when or where resources are encountered, and samples movement lengths independently of past experience. However, LĂŠvy processes too have come into question based on the observation that in patchy resource environments resource-sensitive foraging strategies, like area-restricted search, perform better than LĂŠvy flights yet can still generate heavy-tailed distributions of movement lengths. To investigate these questions further, we tracked humans as they searched for hidden resources in an open-field virtual environment, with either patchy or dispersed resource distributions. Supporting previous research, for both conditions logarithmic binning methods were consistent with LĂŠvy flights and rank-frequency methodsâcomparing alternative distributions using maximum likelihood methodsâshowed the strongest support for bounded power-law distributions (truncated LĂŠvy flights). However, goodness-of-fit tests found that even bounded power-law distributions only accurately characterized movement behavior for 4 (out of 32) participants. Moreover, paths in the patchy environment (but not the dispersed environment) showed a transition to intensive search following resource encounters, characteristic of area-restricted search. Transferring paths between environments revealed that paths generated in the patchy environment were adapted to that environment. Our results suggest that though power-law distributions do not accurately reflect human search, LĂŠvy processes may still describe movement in dispersed environments, but not in patchy environmentsâwhere search was area-restricted. Furthermore, our results indicate that search strategies cannot be inferred without knowing how organisms respond to resourcesâas both patched and dispersed conditions led to similar LĂŠvy-like movement distributions
Improving Acquisitions In Science And Technology Programs: Creating Unique Cost Factors To Improve Resource Allocation Decisions
Acquisition Research Program Sponsored Report SeriesSponsored Acquisition Research & Technical ReportsCost factors are a common technique employed in Major Defense Acquisition Program (MDAP) cost estimating. The extant suite of available factors, however, primarily consists of development factors from the Engineering and Manufacturing Development (EMD) phase of the life cycle. This study expands the set of factors available to analysts by producing cost factors germane to programs early in the life cycle (i.e. Science and Technology (S&T) programs) and also creates factors for the Production phase of the life cycle. Cost factor development in S&T programs provides unique challenges due to non-standard reporting requirements. To meet these challenges, this study first mapped S&T cost data to create a new, suggested Work Breakdown Structure (WBS) that mirrors the WBS structure utilized in MDAPs via Mil-Std-881. From this, it was determined that two cost factors commonly utilized in MDAP estimates, Systems Engineering/Program Management (SE/PM) and Systems Test and Evaluation (ST&E) could be derived for the S&T programs. The creation of factors for the production phase of the life cycle resulted in 1033 new cost factors from a multitude of diverse programs. Factors were developed by commodity type (aircraft, missile, UAV, space, and ship), contract type (various), contractor type (prime and sub), and Service (Air Force, Army, and Navy). Combining the results of the previous EMD factors developed (Markman et al., 2019) with the two new phases developed here (S&T; Production) results in a robust cost factor toolkit across the acquisition life cycle spectrum.Approved for public release; distribution is unlimited.Approved for public release; distribution is unlimited
Crustal structure of the Mid Black Sea High from wide-angle seismic data
The Mid Black Sea High comprises two en echelon basement ridges, the Archangelsky and Andrusov ridges, that separate the western and eastern Black Sea basins. The sediment cover above these ridges has been characterized by extensive seismic reflection data, but the crustal structure beneath is poorly known. We present results from a densely sampled wide-angle seismic profile, coincident with a pre-existing seismic reflection profile, which elucidates the crustal structure. We show that the basement ridges are covered by approximately 1â2 km of pre-rift sedimentary rocks. The Archangelsky Ridge has higher pre-rift sedimentary velocities and higher velocities at the top of basement (c. 6 km sâ1). The Andrusov Ridge has lower pre-rift sedimentary velocities and velocities less than 5 km sâ1 at the top of the basement. Both ridges are underlain by approximately 20-km-thick crust with velocities reaching around 7.2 km sâ1 at their base, interpreted as thinned continental crust. These high velocities are consistent with the geology of the Pontides, which is formed of accreted island arcs, oceanic plateaux and accretionary complexes. The crustal thickness implies crustal thinning factors of approximately 1.5â2. The differences between the ridges reflect different sedimentary and tectonic histories
Theoretical studies of the historical development of the accounting discipline: a review and evidence
Many existing studies of the development of accounting thought have either been atheoretical or have adopted Kuhn's model of scientific growth. The limitations of this 35-year-old model are discussed. Four different general neo-Kuhnian models of scholarly knowledge development are reviewed and compared with reference to an analytical matrix. The models are found to be mutually consistent, with each focusing on a different aspect of development. A composite model is proposed. Based on a hand-crafted database, author co-citation analysis is used to map empirically the entire literature structure of the accounting discipline during two consecutive time periods, 1972â81 and 1982â90. The changing structure of the accounting literature is interpreted using the proposed composite model of scholarly knowledge development
Genomics reveals historic and contemporary transmission dynamics of a bacterial disease among wildlife and livestock
Whole-genome sequencing has provided fundamental insights into infectious disease epidemiology, but has rarely been used for examining transmission dynamics of a bacterial pathogen in wildlife. In the Greater Yellowstone Ecosystem (GYE), outbreaks of brucellosis have increased in cattle along with rising seroprevalence in elk. Here we use a genomic approach to examine Brucella abortus evolution, cross-species transmission and spatial spread in the GYE. We find that brucellosis was introduced into wildlife in this region at least five times. The diffusion rate varies among Brucella lineages (âź3 to 8âkm per year) and over time. We also estimate 12 host transitions from bison to elk, and 5 from elk to bison. Our results support the notion that free-ranging elk are currently a self-sustaining brucellosis reservoir and the source of livestock infections, and that control measures in bison are unlikely to affect the dynamics of unrelated strains circulating in nearby elk populations
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