312 research outputs found
Chopping: A generalization of slicing
A new method for extracting partial representations of a program is described. Given two sets of variable instances, source and sink, a graph is constructed showing the statements that cause definitions of source to affect uses of sink. This criterion can express a wider range of queries than the various forms of slice criteria, which it subsumes as special cases. On the standard slice criterion (backward slicing from a use or definition) it produces better results than existing algorithms. The method is modular. By treating all statements abstractly as def-use relations, it can present a procedure call as a simple statement, so that it appears in the graph as a single node whose role may be understood without looking beyond the context of the call
Impact of Illness Management and Recovery Programs on Hospital and Emergency Room Use by Medicaid Enrollees
Objective—Illness management and recovery is a structured program that helps consumers with severe mental illness learn effective ways to manage illness and pursue recovery goals. This study
examined the impact of the program on health service utilization.
Methods—This was a retrospective cohort study of five assertive community treatment (ACT) teams in Indiana that implemented illness management and recovery. With Medicaid claims data
from July 1, 2003, to June 30, 2008, panel data were created with person-months as the level of analysis, resulting in 14,261 observations, for a total of 498 unique individuals. Zero-inflated negative binomial regression models were used to predict hospitalization days and emergency room visits, including covariates of demographic characteristics, employment status, psychiatric diagnosis, and concurrent substance use disorder. The main predictor variables of interest were
receipt of illness management and recovery services, dropout from the program, and program graduation status.
Results—Consumers who received some illness management and recovery services had fewer hospitalization days than those receiving only ACT. Graduates had fewer emergency room visits than did ACT-only consumers.
Conclusions—This is the first study to examine the impact of illness management and recovery on service utilization. Controlling for a number of background variables, the study showed that
illness management and recovery programs were associated with reduced inpatient hospitalization and emergency room use over and above ACT
Slow light with a swept-frequency source
We introduce a new concept for stimulated-Brillouin-scattering-based slow
light in optical fibers that is applicable for broadly-tunable frequency-swept
sources. It allows slow light to be achieved, in principle, over the entire
transparency window of the optical fiber. We demonstrate a slow light delay of
10 ns at 1550 nm using a 10-m-long photonic crystal fiber with a source sweep
rate of 0.4 MHz/ns and a pump power of 200 mW. We also show that there exists a
maximal delay obtainable by this method, which is set by the SBS threshold,
independent of sweep rate. For our fiber with optimum length, this maximum
delay is ~38 ns, obtained for a pump power of 760 mW.Comment: 6 pages, 5 figure
Origins and population genetics of sambar deer (Cervus unicolor) introduced to Australia and New Zealand
Context. Some populations of introduced species cause significant undesirable impacts but can also
act as reservoirs for genetic diversity. Sambar deer (Cervus unicolor) are ‘Vulnerable’ in their native
range and invasive in Australia and New Zealand. Genetic data can be used to determine whether
these introduced populations might serve as genetic reservoirs for declining native populations and
to identify spatial units for management. Aims. We aimed to identify the provenance of sambar deer
in Australia and New Zealand, and to characterise their genetic diversity and population structure.
Methods. We used mitochondrial control region sequences and 18 nuclear microsatellite loci of 24
New Zealand and 63 Australian sambar deer collected across continuous habitat in each location.
We estimated genetic diversity and population differentiation by using pairwise FST, AMOVA, and
STRUCTURE analyses. We compared our data with 27 previously published native and invasive range
sequences to identify phylogenetic relationships. Key results. Sambar deer in Australia and New
Zealand are genetically more similar to those in the west of the native range (South and Central
Highlands of India, and Sri Lanka), than to those in the east (eastern India, and throughout Southeast
Asia). Nuclear genetic diversity was lower than in the native range; only one mitochondrial haplotype
was found in each introduced population. Australian and New Zealand sambar deer were genetically
distinct but there was no population structure within either population. Conclusions. The genetic
differences we identified between these two introduced populations at putatively neutral loci
indicate that there also may be underlying diversity at functional loci. The lack of population genetic
structure that we found within introduced populations suggests that individuals within these popula-
tions do not experience barriers to dispersal across the areas sampled. Implications. Although
genetic diversity is reduced in the introduced range compared with the native range, sambar deer
in Australia and New Zealand harbour unique genetic variants that could be used to strengthen
genetic diversity in populations under threat in the native range. The apparent high levels of gene
flow across the areas we sampled suggest that localised control is unlikely to be effective in Australia
and New Zealand
Chytridiomycosis and Amphibian Population Declines Continue to Spread Eastward in Panama
Chytridiomycosis is a globally emerging disease of amphibians and the leading cause of population declines and extirpations at species-diverse montane sites in Central America. We continued long-term monitoring efforts for the presence of the fungal pathogen Batrachochytrium dendrobatidis (Bd) and for amphibian populations at two sites in western Panama, and we began monitoring at three new sites to the east. Population declines associated with chytridiomycosis emergence were detected at Altos de Campana National Park. We also detected Bd in three species east of the Panama Canal at SoberanÃa National Park, and prevalence data suggests that Bd may be enzootic in the lowlands of the park. However, no infected frogs were found further east at Tortà (prevalence <7.5% with 95% confidence). Our results suggest that Panama's diverse and not fully described amphibian communities east of the canal are at risk. Precise predictions of future disease emergence events are not possible until factors underlying disease emergence, such as dispersal, are understood. However, if the fungal pathogen spreads in a pattern consistent with previous disease events in Panama, then detection of Bd at Tortà and other areas east of the Panama Canal is imminent. Therefore, development of new management strategies and increased precautions for tourism, recreation, and biology are urgently neede
A public health approach for deciding policy on infant feeding and mother-infant contact in the context of COVID-19
The COVID-19 pandemic has raised concern about the possibility and effects of mother-infant transmission of SARS-CoV-2 through breastfeeding and close contact. The insufficient available evidence has resulted in differing recommendations by health professional associations and national health authorities. We present an approach for deciding public health policy on infant feeding and mother-infant contact in the context of COVID-19, or for future emerging viruses, that balances the risks that are associated with viral infection against child survival, lifelong health, and development, and also maternal health. Using the Lives Saved Tool, we used available data to show how different public health approaches might affect infant mortality. Based on existing evidence, including population and survival estimates, the number of infant deaths in low-income and middle-income countries due to COVID-19 (2020-21) might range between 1800 and 2800. By contrast, if mothers with confirmed SARS-CoV-2 infection are recommended to separate from their newborn babies and avoid or stop breastfeeding, additional deaths among infants would range between 188 000 and 273 000
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HYBRID HETEROGENEOUS CATALYSTS FOR HYDROGENATION OF CARBON DIOXIDE
HYBRID HETEROGENEOUS CATALYSTS FOR HYDROGENATION OF CARBON DIOXIDE Lucia M. Petkovic, Harry W. Rollins, Daniel M. Ginosar, and Kyle C. Burch Idaho National Laboratory P.O. Box 1625 Idaho Falls, ID 83415-2208 Introduction Anthropogenic emissions of carbon dioxide, a gas often associated with global warming, have increased considerably since the beginning of the industrial age.1 In the U.S., stationary CO2 sources, such as electricity generation plants, produce about one-third of the anthropogenic CO2 generation. Reports2 indicate that the power required to recover 90% of the CO2 from an integrated coal-fired power-plant is about 10% of the power-plant capacity. This energy requirement can be reduced to less than 1% if the recovered CO2 is applied to the production of synthetic fuels. However, the lack of efficient catalysts along with the costs of energy and hydrogen has prevented the development of technologies for direct hydrogenation of CO2.3 Although the cost of hydrogen for hydrogenating CO2 is not economically attractive at present, the future production of hydrogen by nuclear power sources could completely change this scenario.2 Still, an efficient catalyst will be essential for commercial application of those processes. The objective of the work presented here was the development of hybrid catalysts for one-step carbon dioxide hydrogenation to liquid fuels. The hybrid catalysts, which were prepared by two novel techniques, included a copper/zinc oxide catalytic function distributed within an acidic zeolitic matrix. Results of catalyst activity and selectivity studies at atmospheric pressure are presented in this contribution. Experimental Catalysts were prepared by two novel techniques and under several different conditions to produce copper/zinc oxide/zeolite materials. Once synthesized, samples were pelletized and the fraction between 40-60 mesh was utilized for the experiments. Two hundred milligrams of catalyst were loaded in a U-tube stainless steel reactor and a flow of 100 cm3/min of a 10:90 H2:Ar mixture was passed through the catalyst bed while the temperature was increased from room temperature to 513 K at 1.8 K/min and held at 513 K for 15 h. A reactant gas mixture composed by 10 cm3/min of CO2 and 30 cm3/min of H2 was then passed through the catalyst bed and the reaction products monitored by on-line gas chromatographic analyses using an SRI Multiple Gas Analyzer #2 equipped with 3 columns (MoleSieve 13X, Hayesep-D, and MXT-1) and 3 detectors (TCD, FID, and FID-methanizer). This GC system allowed for quantification of inert gases, CO, CO2, methanol, dimethylether, higher alcohols, water, and hydrocarbons up to C20. One hundred milligrams of a commercial syngas-to-methanol catalyst along with the same amount of a commercial zeolite catalyst was utilized under the same reaction conditions for comparison purposes. These catalysts were utilized either in two-layers (Com1) or mixed together (Com2). Results and Discussion Under the conditions applied in this study, the main reaction products were CO, CH3OH, CH3OCH3, and H2O. Methanol and dimethylether production rates and selectivities with respect to CO formation are presented in Figures 1 and 2, respectively. Although the activity of the synthesized catalysts did not surpass the commercial catalysts, the selectivity to oxygenates with respect to CO on most of the synthesized catalysts were better than on the commercial catalysts. For example, ca
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