9,385 research outputs found
Bilingualism : the two languages of young people in care
Institutions create their own languages, which become embedded in everyday experience (van Dijk, 1995). In order to function successfully, those in the subordinate position in the institution must learn the language of the institution. Residential child care is one such institution. Institutions and institutional language can be understood on the micro scale of a foster home or a group home or on the macro level of societal relations (Smith, 1999). Those in a less powerful position (i.e. young people in residential care) have no choice but to learn the language of the more powerful (Freire, 1985). Those in a position of authority (i.e. staff within the institutions) could choose to learn the language of the young people who occupy as less powerful position; however, they have no need to do so. Many examples of this can be cited, such as those of bilingual French Canadians as compared to unilingual English Canadians, bilingual Palestinians living in Israel as compared to unilingual Israelis, or even children in care as compared to the professionals in the system which cares for them
A prospective study of the prevalence of corneal surface disease in dogs receiving prophylactic topical lubrication under general anesthesia
Optimal bait density for delivery of acute toxicants to vertebrate pests
Oral baiting is a fundamental method for delivering toxicants to pest species. Planning baiting strategies is challenging because bait-consumption rates depend on dynamic processes including space use and demographics of the target species. To determine cost-effective strategies for optimizing baiting, we developed a spatially explicit model of population dynamics using field-based measures of wild-pig (Sus scrofa) space use, bait consumption, and mortality probabilities. The most cost-effective baiting strategy depended strongly on the population reduction objective and initial density. A wide range of baiting strategies were cost-effective when the objective was 80% population reduction. In contrast, only a narrow range of baiting strategies allowed for a 99% reduction. Cost-effectiveness was lower for low densities of wild pigs because of the increased effort for locating target animals. Bait avoidance due to aversive conditioning from sub-lethal dosing had only minor effects on cost-effectiveness when the objective was an 80% reduction, whereas the effect was much stronger when the objective was 99% population reduction. Our results showed that a bait-based toxicant could be cost-effective for substantially reducing populations of wild pigs, but for elimination it may be most cost-effective to integrate additional management techniques following initial toxicant deployment. The nonlinear interaction of cost-effectiveness, initial population size, and reduction objective also emphasized the importance of considering the dynamics of space use and bait consumption for predicting effective baiting strategies. Although we used data for an acute toxicant and wild-pig consumption rates, our framework can be readily adapted to other vertebrate pest species and toxicant characteristics
Controlled Growth, Patterning and Placement of Carbon Nanotube Thin Films
Controlled growth, patterning and placement of carbon nanotube (CNT) thin
films for electronic applications are demonstrated. The density of CNT films is
controlled by optimizing the feed gas composition as well as the concentration
of growth catalyst in a chemical vapor deposition process. Densities of CNTs
ranging from 0.02 CNTs/{\mu}m^2 to 1.29 CNTs/{\mu}m^2 are obtained. The
resulting pristine CNT thin films are then successfully patterned using either
pre-growth or post-growth techniques. By developing a layered photoresist
process that is compatible with ferric nitrate catalyst, significant
improvements over popular pre-growth patterning methods are obtained.
Limitations of traditional post-growth patterning methods are circumvented by
selective transfer printing of CNTs with either thermoplastic or metallic
stamps. Resulting as-grown patterns of CNT thin films have edge roughness (< 1
{\mu}m) and resolution (< 5 {\mu}m) comparable to standard photolithography.
Bottom gate CNT thin film devices are fabricated with field-effect mobilities
up to 20 cm^2/Vs and on/off ratios of the order of 10^3. The patterning and
transfer printing methods discussed here have a potential to be generalized to
include other nanomaterials in new device configurations
The MISSE 7 Flexural Stress Effects Experiment After 1.5 Years of Wake Space Exposure
Low Earth orbit space environment conditions, including ultraviolet radiation, thermal cycling, and atomic oxygen exposure, can cause degradation of exterior spacecraft materials over time. Radiation and thermal exposure often results in bond- breaking and embrittlement of polymers, reducing mechanical strength and structural integrity. An experiment called the Flexural Stress Effects Experiment (FSEE) was flown with the objective of determining the role of space environmental exposure on the degradation of polymers under flexural stress. The FSEE samples were flown in the wake orientation on the exterior of International Space Station for 1.5 years. Twenty-four samples were flown: 12 bent over a 0.375 in. mandrel and 12 were over a 0.25 in. mandrel. This was designed to simulate flight configurations of insulation blankets on spacecraft. The samples consisted of assorted polyimide and fluorinated polymers with various coatings. Half the samples were designated for bend testing and the other half will be tensile tested. A non-standard bend-test procedure was designed to determine the surface strain at which embrittled polymers crack. All ten samples designated for bend testing have been tested. None of the control samples' polymers cracked, even under surface strains up to 19.7%, although one coating cracked. Of the ten flight samples tested, seven show increased embrittlement through bend-test induced cracking at surface strains from 0.70%to 11.73%. These results show that most of the tested polymers are embrittled due to space exposure, when compared to their control samples. Determination of the extent of space induced embrittlement of polymers is important for designing durable spacecraft
Spontaneous Regression of Pulmonary and Adrenal Metastases Following Percutaneous Radiofrequency Ablation of a Recurrent Renal Cell Carcinoma
The spontaneous regression of metastatic lesions from renal cell carcinoma (RCC) is extremely rare, but may be encountered following cytoreductive treatments. We report a case of a recurrent RCC with multiple metastatic lesions which spontaneously regressed after undergoing radiofrequency ablation of the renal tumor
Performance of an Operating High Energy Physics Data Grid: D0SAR-Grid
The D0 experiment at Fermilab's Tevatron will record several petabytes of
data over the next five years in pursuing the goals of understanding nature and
searching for the origin of mass. Computing resources required to analyze these
data far exceed capabilities of any one institution. Moreover, the widely
scattered geographical distribution of D0 collaborators poses further serious
difficulties for optimal use of human and computing resources. These
difficulties will exacerbate in future high energy physics experiments, like
the LHC. The computing grid has long been recognized as a solution to these
problems. This technology is being made a more immediate reality to end users
in D0 by developing a grid in the D0 Southern Analysis Region (D0SAR),
D0SAR-Grid, using all available resources within it and a home-grown local task
manager, McFarm. We will present the architecture in which the D0SAR-Grid is
implemented, the use of technology and the functionality of the grid, and the
experience from operating the grid in simulation, reprocessing and data
analyses for a currently running HEP experiment.Comment: 3 pages, no figures, conference proceedings of DPF04 tal
Bend-Test Results of the MISSE 7 Flexural Stress Effects Experiment After 1.5 Years of Space Exposure
Low Earth orbital environmental exposure can cause degradation of exterior spacecraft materials. Radiation and thermal exposure often result in bond-breaking and embrittlement of polymers, reducing mechanical strength and structural integrity. The Flexural Stress Effects Experiment (FSEE) was flown with the objective of determining the role of space exposure on the degradation of polymers under flexural stress. The FSEE samples were flown in a wake orientation on the exterior of International Space Station for 1.5 years. Twenty-three polyimide and fluorinated polymers with various coatings were flown: 11 bent over a 0.375-inch diameter holder and 12 over a 0.25-inch diameter holder. A non-standard bend-test procedure was used to determine the surface strain at which embrittled polymers crack. None of the control samples cracked, even under surface strains up to 19.7%, although one coating cracked. Of the 10 flight samples tested, seven indicated increased embrittlement through bend-test cracking at surface strains from 0.65% to 8.11%. Therefore, most of the tested polymers were embrittled due to space exposure, when compared to their control samples. The samples flown over the 0.375-inch holder were more embrittled than those on the 0.25-inch holder. Determination of the extent of space induced embrittlement of polymers is important for designing durable spacecraft
Accounting for observation processes across multiple levels of uncertainty improves inference of species distributions and guides adaptive sampling of environmental DNA
Understanding factors that influence observation processes is critical for accurate assessment of underlying ecological processes. When indirect methods of detection, such as environmental DNA, are used to determine species presence, additional levels of uncertainty from observation processes need to be accounted for. We conducted a field trial to evaluate observation processes of a terrestrial invasive species (wild pigs‐ Sus scrofa) from DNA in water bodies. We used a multi‐scale occupancy analysis to estimate different levels of observation processes (detection, p): the probability DNA is available per sample (θ), the probability of capturing DNA per extraction (γ), and the probability of amplification per qPCR run (δ). We selected four sites for each of three water body types and collected 10 samples per water body during two months (September and October 2016) in central Texas. Our methodology can be used to guide sampling adaptively to minimize costs while improving inference of species distributions. Using a removal sampling approach was more efficient than pooling samples and was unbiased. Availability of DNA varied by month, was considerably higher when water pH was near neutral, and was higher in ephemeral streams relative to wildlife guzzlers and ponds. To achieve a cumulative detection probability \u3e90% (including availability, capture, and amplification), future studies should collect 20 water samples per site, conduct at least two extractions per sample, and conduct five qPCR replicates per extraction. Accounting for multiple levels of uncertainty of observation processes improved estimation of the ecological processes and provided guidance for future sampling designs
Interstellar extinction and polarization -- A spheroidal dust grain approach perspective
We extend and investigate the spheroidal model of interstellar dust grains
used to simultaneously interpret the observed interstellar extinction and
polarization curves. We compare our model with similar models recently
suggested by other authors, study its properties and apply it to fit the
normalized extinction and the polarizing efficiency
measured in the near IR to far UV region for several
stars seen through one large cloud. We conclude that the model parameter
being the angle between the line of sight and the magnetic field
direction can be more or less reliably determined from comparison of the theory
and observations. This opens a way to study the spatial structure of
interstellar magnetic fields by using multi-wavelength photometric and
polarimetric observations.Comment: 11 pages, 4 figures and 4 tables, To appear in MNRAS (added
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