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81.
Schwartz Sonia; Hoyte Joel; James Thea; Conoscenti Lauren; Johnson Renee; Liebschutz Jane 《Canadian Metallurgical Quarterly》2010,2(1):54
A dearth of literature exists on barriers to conducting research with Black male victims of community violence, despite the need for evidence-based postinjury interventions. This study used qualitative data from a cross-sectional interview study (n = 16) and a pilot intervention study (n = 11) conducted in Boston, MA to identify challenges and facilitators to conducting research with Black male victims of community violence, particularly with regard to recruitment and maintenance of a study sample. Qualitative methods, including Grounded Theory and ethnography, were used to analyze the data. Challenges included a fear of police involvement, an impression of “snitching” when disclosing personal information, mistrust of research motives, suspicion of the informed consent process, the emotional impact of the trauma itself, and logistical issues. Facilitators to research included monetary incentives and motivation to help oneself and others. Participant recommendations on recruitment methods relating to approach and timing are provided. Findings from this study may assist in the planning of research studies for Black male victims of community violence. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
82.
Peter Politzer Jane S. Murray M. Edward Grice Tore Brinck 《Journal of Energetic Materials》2013,31(2-3):89-95
Abstract Two proposed ionic compounds, NH4O2 and NH4O3, are discussed in terms of several properties related to energetic performance. These include oxygen content, moles of gas produced and heat released upon decomposition, and specific impulse. The heat release was calculated in each instance using the predicted lattice energy, which was obtained from the computed electrostatic potential on the surface of the negative ion. NH4O2 is found to be superior to HMX in each property considered, while NH4O3 is better than HMX in some and comparable in the others. 相似文献
83.
Trinocular Stereo: A Real-Time Algorithm and its Evaluation 总被引:1,自引:0,他引:1
Jane Mulligan Volkan Isler Kostas Daniilidis 《International Journal of Computer Vision》2002,47(1-3):51-61
In telepresence applications each user is immersed in a rendered 3D-world composed from representations transmitted from remote sites. The challenge is to compute dense range data at high frame rates, since participants cannot easily communicate if the processing cycle or network latencies are long. Moreover, errors in new stereoscopic views of the remote 3D-world should be hardly perceptible. To achieve the required speed and accuracy, we use trinocular stereo, a matching algorithm based on the sum of modified normalized cross-correlations, and subpixel disparity interpolation. To increase speed we use Intel IPL functions in the pre-processing steps of background subtraction and image rectification as well as a four-processor parallelization. To evaluate our system we have developed a test-bed which provides a set of registered dense ground-truth laser data and image data from multiple views. 相似文献
84.
Spam filtering is a text classification task to which Case-Based Reasoning (CBR) has been successfully applied. We describe
the ECUE system, which classifies emails using a feature-based form of textual CBR. Then, we describe an alternative way to
compute the distances between cases in a feature-free fashion, using a distance measure based on text compression. This distance
measure has the advantages of having no set-up costs and being resilient to concept drift. We report an empirical comparison,
which shows the feature-free approach to be more accurate than the feature-based system. These results are fairly robust over
different compression algorithms in that we find that the accuracy when using a Lempel-Ziv compressor (GZip) is approximately
the same as when using a statistical compressor (PPM). We note, however, that the feature-free systems take much longer to
classify emails than the feature-based system. Improvements in the classification time of both kinds of systems can be obtained
by applying case base editing algorithms, which aim to remove noisy and redundant cases from a case base while maintaining,
or even improving, generalisation accuracy. We report empirical results using the Competence-Based Editing (CBE) technique.
We show that CBE removes more cases when we use the distance measure based on text compression (without significant changes
in generalisation accuracy) than it does when we use the feature-based approach. 相似文献
85.
Hernandez Giovanni; Hamdani Selma; Rajabi Heshmat; Conover Kent; Stewart Jane; Arvanitogiannis Andreas; Shizgal Peter 《Canadian Metallurgical Quarterly》2006,120(4):888
Extracellular dopamine levels were measured in the rat nucleus accumbens by means of in vivo microdialysis. Delivery of rewarding medial forebrain bundle stimulation at a low rate (5 trains/min) produced a sustained elevation of dopamine levels, regardless of whether train onset was predictable. When the rate of train delivery was increased to 40 trains/min, dopamine levels rose rapidly during the first 40 min but then declined toward the baseline range. The rewarding impact of the stimulation was reduced following prior delivery of stimulation at the high, but not the low, rate. These results support the idea that dopamine tone plays an enabling role in brain stimulation reward and is elevated similarly by predictable and unpredictable stimulation. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
86.
Crowell Sheila E.; Beauchaine Theodore P.; Gatzke-Kopp Lisa; Sylvers Patrick; Mead Hilary; Chipman-Chacon Jane 《Canadian Metallurgical Quarterly》2006,115(1):174
Numerous studies have revealed autonomic underarousal in conduct-disordered adolescents and antisocial adults. It is unknown, however, whether similar autonomic markers are present in at-risk preschoolers. In this study, the authors compared autonomic profiles of 4- to 6-year-old children with attention-deficit/hyperactivity disorder (ADHD) and oppositional defiant disorder (ODD; n = 18) with those of age-matched controls (n = 20). Children with ADHD and ODD exhibited fewer electrodermal responses and lengthened cardiac preejection periods at baseline and during reward. Although group differences were not found in baseline respiratory sinus arrhythmia, heart rate changes among ADHD and ODD participants were mediated exclusively by parasympathetic withdrawal, with no independent sympathetic contribution. Heart rate changes among controls were mediated by both autonomic branches. These results suggest that at-risk preschoolers are autonomically similar to older externalizing children. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
87.
To date, long-term preservation approaches have comprised of emulation, migration, normalization, and metadata – or some combination
of these. Most existing work has focussed on applying these approaches to digital objects of a singular media type:
text, HTML, images, video or audio. In this paper, we consider the preservation of composite, mixed-media digital objects,
a rapidly growing class of resources. We describe an integrated, flexible system that we have developed, which leverages existing
tools and services and assists organizations to dynamically discover the optimum preservation strategy as it is required.
The system captures and periodically compares preservation metadata with software and format registries to determine those
objects (or sub-objects) at risk. By making preservation software modules available as Web services and describing them semantically
using a machine-processable ontology (OWL-S), the most appropriate preservation service(s) for each object (or sub-object)
can then be dynamically discovered, composed and invoked by software agents (with optional human input at critical decision-making
steps). The PANIC system successfully illustrates how the growing array of available preservation tools and services can be
integrated to provide a sustainable, collaborative solution to the long-term preservation of large-scale collections of complex
digital objects. 相似文献
88.
The elicitation or communication of user requirements comprises an early and critical but highly error-prone stage in system
development. Socially oriented methodologies provide more support for user involvement in design than the rigidity of more
traditional methods, facilitating the degree of user–designer communication and the ‘capture’ of requirements. A more emergent
and collaborative view of requirements elicitation and communication is required to encompass the user, contextual and organisational
factors. From this accompanying literature in communication issues in requirements elicitation, a four-dimensional framework
is outlined and used to appraise comparatively four different methodologies seeking to promote a closer working relationship
between users and designers. The facilitation of communication between users and designers is subject to discussion of the
ways in which communicative activities can be ‘optimised’ for successful requirements gathering, by making recommendations
based on the four dimensions to provide fruitful considerations for system designers. 相似文献
89.
Spence Susan H.; Holmes Jane M.; March Sonja; Lipp Ottmar V. 《Canadian Metallurgical Quarterly》2006,74(3):614
Seventy-two clinically anxious children, aged 7 to 14 years, were randomly allocated to clinic-based, cognitive-behavior therapy, the same treatment partially delivered via the Internet, or a wait-list control (WL). Children in the clinic and clinic-plus-Internet conditions showed significantly greater reductions in anxiety from pre- to posttreatment and were more likely to be free of their anxiety diagnoses, compared with the WL group. Improvements were maintained at 12-month follow-up for both therapy conditions, with minimal difference in outcomes between interventions. The Internet treatment content was highly acceptable to families, with minimal dropout and a high level of therapy compliance. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
90.
Ferroelectric domain configurations in PbTiO3 and Pb(ZrxT1−x)O3 (PZT, x = 0.3 or 0.5) thin films have been studied by transmission electron microscopy. The PbTiOg and PZT thin films have
been deposited by the ionized cluster beam technique and radio frequency sputtering, respectively. The grain size in these
thin films is typically less than 0.5 μm. Lamellar 90°-domain features have been observed in both PbTiO3 and PZT (30/70) samples. The domain walls correspond to the {011} twin boundaries. La-doping and Ca-modification are shown
to affect the microstructure of the PZT films. No clear domain feature occurs in the PZT thin film that has composition near
the morphotropic phase boundary. The effects of grain sizes are briefly discussed. 相似文献