693 research outputs found
"The Measurement of Chronic and Transitory Poverty: with Application to the United States"
This paper proposes a method of measuring chronic and transitory poverty based on any additively-decomposable index of aggregate poverty. Chronic poverty and transitory poverty in the United States are measured using data from the Panel Study of Income Dynamics (1987 interviewing year). In an attempt to identify the most impoverished subpopulations, poverty indices are decomposed according to race, type of household and educational qualifications of the head of the household.
The Effect of Geographic Mobility on Male Labour-Force Particpants in the United States
We use both fixed-effects and random-effects regression models to measure the effect of geographic mobility on earnings of labor-force participants in the United States. The results support the human-capital hypothesis: six years after moving, real earnings of male labor-force participants are about 20 percent higher than they would have been had the move not occurred. Men younger than 40, and men with family-unit incomes no more than five times the poverty line, experience even larger benefits from moving. The geographic mobility that is characteristic of the United States’ flexible labor market, in general, is beneficial to the movers
Characterizing DemographicParameters Across Environmental Gradients: A Case Study With Ontario Moose
Population-level demographic characteristics as estimated by standard logistic growth models (i.e., carrying capacity and intrinsic growth rate) should vary with changes in habitat quality and availability of resources. However, few published studies have tested this hypothesis by comparing population growth rates across broad bioclimatic gradients, and fewer still the carrying capacities of those populations. We used time series data on moose (Alces alces) population densities based on aerial census and hunter harvest data for 34 management units across Ontario to estimate local carrying capacities and intrinsic growth rates. These population parameters were then regressed against associated habitat covariates for each management unit to assess how moose demography changes across a broad gradient of productivity, habitat abundance, and timber harvest. Moose carrying capacity was found to increase with increasing forest productivity as measured by DNDVI and the proportion of mixedwood stands in the forest. Both variables are plausibly indicative of high quality forage abundance for moose. Moose carrying capacity decreased with the proportion of forest stands harvested for timber annually, suggesting that immediate removal of forest stands and increased access by hunters temper maximum population size. Maximum rates of population growth by Ontario moose did not vary predictably with any of the landscape covariates tested. These findings contribute to our understanding of changes in demography across broad geographic and bioclimatic gradients and suggest that crude population estimators may be derived based on known habitat preferences and resource availability without a priori knowledge of animal abundance. (PDF) Characterizing demographic parameters across environmental gradients: A case study with Ontario moose (Alces alces). Available from: https://www.researchgate.net/publication/280936410_Characterizing_demographic_parameters_across_environmental_gradients_A_case_study_with_Ontario_moose_Alces_alces [accessed Oct 29 2018]
Quantitative PCR assays for detection of five Alaskan fish species: Lota lota, Salvelinus alpinus, Salvelinus malma, Thymallus arcticus, and Cottus cognatus from environmental DNA
The North Slope of Alaska contains arctic fish populations that are important for subsistence of local human populations, and under threat from natural resource extraction and climate change. We designed and evaluated four quantitative PCR assays for detection of environmental DNA from five Alaskan fish species present on the North Slope of Alaska: burbot (Lota lota), arctic char (Salvelinus alpinus), Dolly Varden (Salvelinus malma), arctic grayling (Thymallus arcticus), and slimy sculpin (Cottus cognatus). All assays were designed and tested for species specificity and sensitivity, and all assays detected target species from filtered water samples collected from the field. These assays will enable efficient and economical detection of the above species from lakes and rivers. This in turn will provide managers with improved knowledge of current distributions and future range shifts associated with climate and development threats, enabling more timely management
Effects of national housing quality standards on hospital emergency admissions: a quasi-experiment using data-linkage
Background
National housing quality standards are now being applied throughout the UK. The Welsh Government has introduced the Welsh Housing Quality Standards. A housing improvement programme in Wales has been delivered through one local authority to bring 9500 homes up to standard. Homes received multiple elements, including new kitchens, bathrooms, windows and doors, boilers, insulation, and wiring, through an 8 year rolling work programme. The study aimed to determine the impacts of the different housing improvements on hospital emergency admissions for residents over 60 years of age.
Methods
Intervention homes (council homes that received at least one element of work) were data linked to individual health records of residents. Counts of admissions for respiratory and cardiovascular conditions, and for falls and burns, were obtained retrospectively for each individual in a dynamic housing cohort (Jan 1, 2005, to March 31, 2015). The criterion for the intervention cohort was for someone to have lived in any one of the 9500 intervention homes for at least 3 months within the intervention period. Counts were captured for up to 123 consecutive months for 7054 individuals in the intervention cohort and analysed in a multilevel approach to account for repeated observations for individuals, nested within geographical areas. Negative binomial regression models were constructed to determine the effect on emergency admissions for those living in homes compliant for each element of work compared with those living in homes that were non-compliant at that time. We adjusted for background trends in the regional general population, and for other confounding factors.
Findings
For residents 60 years old and over there was a reduction in admissions for people with compliant boilers (rate ratio 0·71, 95% CI 0·67–0·76), loft insulation (0·87, 0·80–0·95), wall insulation (0·74, 0·69–0·80), and windows and doors (0·56, 0·52–0·61) compared with those living in homes that were non-compliant for those work elements.
Interpretation
Improving housing to national standards reduces the number of emergency admissions to hospital for older residents. Strengths of the data-linkage approach included the retrospective collection of complete baseline and follow-up data using routine data for a long-term intervention, and large scale regional adjustment
The Wide Field Spectrograph (WiFeS)
This paper describes the Wide Field Spectrograph (WiFeS) under construction
at the Research School of Astronomy and Astrophysics (RSAA) of the Australian
National University (ANU) for the ANU 2.3m telescope at the Siding Spring
Observatory. WiFeS is a powerful integral field, double-beam, concentric,
image-slicing spectrograph designed to deliver excellent thoughput, wavelength
stability, spectrophotometric performance and superb image quality along with
wide spectral coverage throughout the 320-950 nm wavelength region. It provides
a 25x38 arcsec. field with 0.5 arcsec. sampling along each of twenty five 38X1
arcsec slitlets. The output format is optimized to match the 4096x4096 pixel
CCD detectors in each of two cameras individually optimized for the blue and
the red ends of the spectrum, respectively. A process of "interleaved
nod-and-shuffle" will be applied to permit quantum noise-limited sky
subtraction. Using VPH gratings, spectral resolutions of 3000 and 7000 are
provided. The full spectral range is covered in a single exposure at R=3000,
and in two exposures in the R=7000 mode. The use of transmissive coated optics,
VPH gratings and optimized mirror coatings ensures a throughput (including
telescope atmosphere and detector) > 30% over a wide spectral range. The
concentric image-slicer design ensures an excellent and uniform image quality
across the full field. To maximize scientific return, the whole instrument is
configured for remote observing, pipeline data reduction, and the accumulation
of calibration image libraries.Comment: Accepted for publication in Astrophysics & Space Science, 16 pages,
14 figure
(±)-9-exo-Amino-5,6,7,8-tetrahydro-5,8-methano-9H-benzocyclohepten-8-ol Hydrochloride
This is the published version, also available here: http://www.dx.doi.org/10.1107/S0567740878004458
CRYSTMET: a database of the structures and powder patterns of metals and intermetallics
CRYSTMET is a database of critically evaluated crystallographic data for metals (including alloys, intermetallics and minerals) and associated bibliographic, chemical and physical information. Also included are simulated powder diffraction patterns for all of the entries. The database currently contains almost 70000 entries and covers the literature exhaustively from 1922 to the present. The database is available on CD-ROM with search/analysis software for use on personal computers. This software can be used with any database in the appropriate format; currently CRYSTMET and the ICSD databases are available. This paper describes the database content, the procedures used in its construction, the software made available to the user and a number of potential uses for the data
Dynamics of extracellular matrix in ovarian follicles and corpora lutea of mice
Despite the mouse being an important laboratory species, little is known about changes in its extracellular matrix (ECM) during follicle and corpora lutea formation and regression. Follicle development was induced in mice (29 days of age/experimental day 0) by injections of pregnant mare’s serum gonadotrophin on days 0 and 1 and ovulation was induced by injection of human chorionic gonadotrophin on day 2. Ovaries were collected for immunohistochemistry (n=10 per group) on days 0, 2 and 5. Another group was mated and ovaries were examined on day 11 (n=7). Collagen type IV α1 and α2, laminin α1, β1 and γ1 chains, nidogens 1 and 2 and perlecan were present in the follicular basal lamina of all developmental stages. Collagen type XVIII was only found in basal lamina of primordial, primary and some preantral follicles, whereas laminin α2 was only detected in some preantral and antral follicles. The focimatrix, a specialised matrix of the membrana granulosa, contained collagen type IV α1 and α2, laminin α1, β1 and γ1 chains, nidogens 1 and 2, perlecan and collagen type XVIII. In the corpora lutea, staining was restricted to capillary sub-endothelial basal laminas containing collagen type IV α1 and α2, laminin α1, β1 and γ1 chains, nidogens 1 and 2, perlecan and collagen type XVIII. Laminins α4 and α5 were not immunolocalised to any structure in the mouse ovary. The ECM composition of the mouse ovary has similarities to, but also major differences from, other species with respect to nidogens 1 and 2 and perlecan
Stress Preconditioning of Spreading Depression in the Locust CNS
Cortical spreading depression (CSD) is closely associated with important pathologies including stroke, seizures and migraine. The mechanisms underlying SD in its various forms are still incompletely understood. Here we describe SD-like events in an invertebrate model, the ventilatory central pattern generator (CPG) of locusts. Using K+ -sensitive microelectrodes, we measured extracellular K+ concentration ([K+]o) in the metathoracic neuropile of the CPG while monitoring CPG output electromyographically from muscle 161 in the second abdominal segment to investigate the role K+ in failure of neural circuit operation induced by various stressors. Failure of ventilation in response to different stressors (hyperthermia, anoxia, ATP depletion, Na+/K+ ATPase impairment, K+ injection) was associated with a disturbance of CNS ion homeostasis that shares the characteristics of CSD and SD-like events in vertebrates. Hyperthermic failure was preconditioned by prior heat shock (3 h, 45°C) and induced-thermotolerance was associated with an increase in the rate of clearance of extracellular K+ that was not linked to changes in ATP levels or total Na+/K+ ATPase activity. Our findings suggest that SD-like events in locusts are adaptive to terminate neural network operation and conserve energy during stress and that they can be preconditioned by experience. We propose that they share mechanisms with CSD in mammals suggesting a common evolutionary origin
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