877 research outputs found
Survival and cessation in injecting drug users: prospective observational study of outcomes and effect of opiate substitution treatment
Objectives To examine survival and long term cessation of injecting in a cohort of drug users and to assess the influence of opiate substitution treatment on these outcomes
Effects of the sex ratio and socioeconomic deprivation on male mortality
We explored relationships between male mortality and the sex ratio. (We tested relationships across 142 societies and in longitudinal data from Scotland. A male-biased sex ratio was associated with reduced mortality by intentional self-harm across 142 societies. This was replicated in longitudinal Scottish data, and men were less likely to die by suicide and assault when there were more men in the population only when levels of unemployment were low. We argue that this is consistent with a theoretical model in which men increase investment in relationships and offspring as “competition” under a male-biased sex ratio, and that the conflicting results of previous work may stem from divergent effects of the sex ratio on mortality depending upon relative deprivation
From productivism to multi-functionality in the Gascoyne-Murchison Rangelands of Western Australia
A sustainability assessment of the Western Australian (WA) rangelands identified a range of issues associated with regional economic decline typical of many marginal rangeland regions in Australia. As part of a regional rejuvenation strategy, the WA state government purchased selected pastoral lease properties for incorporation into the conservation estate. It was intended as a means of land-use transition from mono-functional productivism to multi-functionality incorporating protection of significant rangeland bioregions and development of tourism. A 1-year project was conducted to assess the issues relating to this transition. Archived information was obtained from government relating to the characteristics of the lease properties at the time they were purchased. Site visits were undertaken to purchased leases acquired by the government as well as neighbouring leases. During site visits, interviews with pastoralists and purchased lease managers were conducted. A series of facilitated community discussion groups in the region was held to ascertain the views of landholders and managers, government representatives, indigenous interests and commercial operators in the region.This paper describes how the transition to a combination of protection and consumption exchanged one set of problems for another. This was due partly to the intrinsic character of the land, in terms of previous overgrazing, isolation, large distances, and limited infrastructure and services. More importantly, the top-down approach to land transition failed to allocate adequate management resources to replace those lost when the former pastoral leaseholders left. The consequences of inadequate management included theft and rapid degradation of assets, inadequate control of pests and weeds; inadequate fire prevention management and poor communication between the government and other stakeholders over management decisions. This paper discusses the dynamics of this WA rangeland transition with reference to the multi-functional rural transition concept
Convergence Acceleration via Combined Nonlinear-Condensation Transformations
A method of numerically evaluating slowly convergent monotone series is
described. First, we apply a condensation transformation due to Van Wijngaarden
to the original series. This transforms the original monotone series into an
alternating series. In the second step, the convergence of the transformed
series is accelerated with the help of suitable nonlinear sequence
transformations that are known to be particularly powerful for alternating
series. Some theoretical aspects of our approach are discussed. The efficiency,
numerical stability, and wide applicability of the combined
nonlinear-condensation transformation is illustrated by a number of examples.
We discuss the evaluation of special functions close to or on the boundary of
the circle of convergence, even in the vicinity of singularities. We also
consider a series of products of spherical Bessel functions, which serves as a
model for partial wave expansions occurring in quantum electrodynamic bound
state calculations.Comment: 24 pages, LaTeX, 12 tables (accepted for publication in Comput. Phys.
Comm.
Optical and radio variability of the BL Lac object AO 0235+16: a possible 5-6 year periodicity
New optical and radio data on the BL Lacertae object AO 0235+16 have been
collected in the last four years by a wide international collaboration, which
confirm the intense activity of this source. The optical data also include the
results of the Whole Earth Blazar Telescope (WEBT) first-light campaign
organized in November 1997. The optical spectrum is observed to basically
steepen when the source gets fainter. We have investigated the existence of
typical variability time scales and of possible correlations between the
optical and radio emissions by means of visual inspection, Discrete Correlation
Function analysis, and Discrete Fourier Transform technique. The major radio
outbursts are found to repeat quasi-regularly with a periodicity of about 5.7
years; this period is also in agreement with the occurrence of some of the
major optical outbursts, but not all of them.Comment: to be published in A&
Campanian-Maastrichtian ocean circulation in the tropical Pacific
The Pacific Ocean is the largest water body on Earth, and circulation in the Pacific
contributed significantly to climate evolution in the latest Cretaceous, the culmination of a
period of long-term cooling. Here, we present new high-resolution late Campanian to
Maastrichtian benthic and planktic foraminiferal stable isotope data and a neodymium (Nd)
isotope record obtained from sedimentary ferromanganese oxide coatings of Ocean Drilling
Program Hole 1210B from the tropical Pacific Ocean (Shatsky Rise). These new records
resolve 13 million years in the latest Cretaceous, providing insights into changes in surface
and bottom water temperatures and source regions of deep to intermediate waters covering
the carbon isotope excursions of the Campanian-Maastrichtian Boundary Event (CMBE)
and the Mid-Maastrichtian event (MME). Our new benthic foraminiferal δ18O and Nd
isotope records together with published Nd isotope data show markedly parallel trends
across the studied interval over a broad range of bathyal to abyssal water depths interpreted
to reflect changes in the intensity of deep-ocean circulation in the tropical Pacific. In
particular, we observe a three-million-year-long period of cooler conditions in the early
Maastrichtian (72.5 to 69.5 Ma) when a concomitant change toward less radiogenic
seawater Nd isotope signatures probably marks a period of enhanced admixture and
northward flow of deep waters with Southern Ocean provenance. We suggest this change to
have been triggered by intensified formation and convection of deep waters in the high
southern latitudes, a process that weakened during the MME (69.5 to 68.5 Ma). The early
Maastrichtian cold interval is closely related to the negative and positive carbon isotope
trends of the CMBE and MME. The millions-of-years long duration of these carbon cycle
perturbations suggests a tectonic forcing of climatic cooling, possibly related to changes in
ocean basin geometry and bathymetry
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