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31.
Martin David J.; Brooks Ronald A.; Ortiz Daniel J.; Veniegas Rosemary C. 《Canadian Metallurgical Quarterly》2003,8(3):181
As treatments have improved health and quality of life for people with HIV/AIDS, many have contemplated workforce reentry. Workforce reentry rarely occurs among people with illness-related disability. The authors mailed a survey that included workforce-entry-related concerns to 1,991 HIV/AIDS clients. Factor analysis extracted 6 areas of concern (benefits loss, work-related health, job skills, discrimination, personal health care, workplace accommodation). Levels of concern generally increased with HIV acuity level and time since last worked. Work-related health concerns predicted consideration of workforce entry, and work-related health concerns and benefits-loss concerns predicted estimated time to return to work. Findings provide quantitative validation of intuitive categories of workforce-entry concerns among people with HIV/AIDS and suggest that concerns may shift with progress toward workforce entry. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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Montmorillinite clays, modified with either Zn(II) or Fe(III) chlorides have been used to catalyze the Friedel-Crafts alkylation of thiophene. High yields (ca. 80%) of 2- and 3-benzylthiophene mixtures were obtained using either catalyst in chlorobenzene or nitrobenzene solvent at 80°C. The ratio of 2–3-products was found to be controlled by their relative stability. Reactions were most rapid in nitrobenzene solution (<5 min) and resulted in formation of the 2-isomer as the only mono-substituted product. This is believed to be the first example in which an alkylation of thiophene has been limited to one regio-isomer. 相似文献
34.
James M. Watkins Ronald Dermott Stephen J. Lozano Edward L. Mills Lars G. Rudstam Jill V. Scharold 《Journal of Great Lakes research》2007,33(3):642-657
The status of invasive dreissenid mussels (Dreissena polymorpha and D. bugensis) and native amphipods (Diporeia spp.) in Lake Ontario was assessed in 2003 and compared with historical data. D. polymorpha (zebra mussels) were rarely observed in 2003, having been displaced by D. bugensis (quagga mussels). D. bugensis expanded its depth range from 38 m depth in 1995 to 174 m in 2003 and this dreissenid reached densities averaging 8,000/m2 at all sites < 90 m. During the same time period, Diporeia populations almost completely disappeared from 0–90 m depth, continuing a declining trend from 1994–1997 reported in previous studies. The average density of Diporeia in the 30–90 m depth interval decreased from 1,380/m2 to 63/m2 between 1997 and 2003. Prior to 2003, areas deeper than 90 m represented a refuge for Diporeia, but even these deep populations decreased, with densities declining from 2,181/m2 in 1999 to 545/m2 in 2003. Two common hypotheses for the decline of Diporeia in the Great Lakes are food limitation and a toxin/pathogen associated with dreissenid pseudofeces. The Diporeia decline in deep waters preceded the expansion of D. bugensis to these depths, and suggests that shallow dreissenid populations remotely influence profundal habitats. This pattern of decline is consistent with mechanisms that act from some distance including nearshore dreissenid grazing and downslope transport of pseudofeces. 相似文献
35.
Ronald E. McRoberts Erkki O. Tomppo Juha Heikkinen 《Remote sensing of environment》2007,111(4):466-480
The k-Nearest Neighbor (k-NN) technique has become extremely popular for a variety of forest inventory mapping and estimation applications. Much of this popularity may be attributed to the non-parametric, multivariate features of the technique, its intuitiveness, and its ease of use. When used with satellite imagery and forest inventory plot data, the technique has been shown to produce useful estimates of many forest attributes including forest/non-forest, volume, and basal area. However, variance estimators for quantifying the uncertainty of means or sums of k-NN pixel-level predictions for areas of interest (AOI) consisting of multiple pixels have not been reported. The primary objectives of the study were to derive variance estimators for AOI estimates obtained from k-NN predictions and to compare precision estimates resulting from different approaches to k-NN prediction and different interpretations of those predictions. The approaches were illustrated by estimating proportion forest area, tree volume per unit area, tree basal area per unit area, and tree density per unit area for 10-km AOIs. Estimates obtained using k-NN approaches and traditional inventory approaches were compared and found to be similar. Further, variance estimates based on different interpretations of k-NN predictions were similar. The results facilitate small area estimation and simultaneous and consistent mapping and estimation of multiple forest attributes. 相似文献
36.
Ronald W. Rousseau James K. Ferrell Robert M. Kelly 《Chemical Engineering Communications》1985,34(1):27-35
Experience with the operation of a pilot-scale unit is used to outline potential difficulties in the operation of acid gas removal systems on gases produced from coal. The pilot plant has been used to condition gases produced from subbituminous coal, devolatilized char, peat and lignite. The solvent used in the acid gas removal system has been refrigerated methyl alcohol. Data from this study document accumulation of hydrocarbons, sulfur and nitrogen compounds, and mercury in the circulating solvent. 相似文献
37.
Disguise and the structured self-report assessment of psychopathology: I. An analogue investigation.
Explored the utility of disguise in structured self-report assessments of psychopathology in 3 experiments with 370 university students. Exp I used items from the Basic Personality Inventory (BPI); Exp II used the BPI, the Desirability scale of the Personality Research Form—Form E, and 4 criterion measures; and Exp III used 2 of the criterion measures and the BPI. Data indicate that under normal test-taking circumstances, the use of disguised test items was not advantageous. This relationship, however, was moderated by a number of dimensional parameters. When faking response sets in terms of desirability was induced, the use of disguised test item content was not useful. Data are interpreted in terms of the various strategies of test construction underlying the assessment of psychopathology. Results support a rational strategy of test construction emphasizing the use of relevant test item content. It is concluded that, in structured self-report assessments, the most valid results may be obtained through the use of direct questions with cooperative test respondents. (43 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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Responses ofRhagoletis pomonella (Walsh) (Diptera: Tephritidae) flies to host fruit visual stimuli (apples or models of apples) and chemical stimuli (synthetic apple volatile blend) were studied in semidwarf field-caged apple trees. Three different fruit or model densities (1, 4, or 16 fruit or models/ tree) and two odor release rates [ca. 0.7g/hr (close to the natural release rate of a ripe apple) and ca. 500g/hr (amount of odor released by commercially sold apple maggot traps)] were tested. Individually released flies were followed as they moved within a tree for a maximum of 20 min. We recorded three-dimensional search paths followed by foraging flies and computed such variables as total relative distance traveled before alighting on a fruit or model, track length between individual alightment sites, and directness of flight to fruits or models. Effect of odor on propensity to alight on fruit or models and host-searching behavior prior to alighting on fruit or on models varied according to fruit or model color and density. If the fruit visual stimulus was strong (e.g., red color), odor did not increase the probability of finding fruit or fruit models. As the visual stimulus became progressively weaker (red to green to clear), odor (irrespective of concentration) appeared to aid flies during the fruit-finding process. As density of fruit or models increased, the probability of flies finding a fruit or model also increased (e.g., 50% of flies found a red fruit model at 1 model/tree while 90% found a red model at 16 models/tree; 4% of flies found a clear model with odor at 1 model/tree while 35% found a clear model with odor at 16 models/tree). Findings reported elsewhere indicate thatR. pomonella flies are able to discover a point source of odor (an odor-bearing tree in a patch of trees) by flying upwind (in the tree patch) in response to intermittent exposure to odor. Findings here indicate that after arrival on a host tree (point source), flies discover individual apparent and abundant host fruit on the basis of vision. If fruit are less apparent or scarce, odor appears to interact with vision during the fruit-finding process. 相似文献
40.
Ronald R. Yager 《国际智能系统杂志》2014,29(10):881-905
Our interest is in the problem of comparing alternatives with uncertain payoffs when the uncertainty is represented using a measure. We first describe various aspects of the use of a measure to represent uncertainty. We recall that probability is a special well‐understood example of measure‐based uncertainty. We note that stochastic dominance provides a well‐established method for comparing alternatives in the case of probabilistic uncertainty. Inspired by this we develop an extension of the use of stochastic dominance for comparing uncertainty profiles to the case where the uncertainty is represented by a measure. We refer to this as measure based stochastic dominance. Do to the fact that in most cases a stochastic dominance relationship does not exist between alternatives this requires us to consider the use of surrogates for measure based stochastic dominance to compare alternatives. Here we investigate a class of surrogates for measure based stochastic dominance that we call Measure Weighted Means (MWM). As we see these MWM are numeric values consistent with measure based stochastic dominance. 相似文献