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101.
Sensitivity of marine microalgae to copper: the effect of biotic factors on copper adsorption and toxicity 总被引:2,自引:0,他引:2
Microalgae are sensitive indicators of environmental change and, as the basis of most freshwater and marine ecosystems, are widely used in the assessment of risk and development of environmental regulations for metals. However, interspecies differences in sensitivity to metals are not well understood. The relationship between metal-algal cell binding and copper sensitivity of marine microalgae was investigated using a series of 72-h growth-rate inhibition bioassays and short-term (1-h) uptake studies. A range of marine algae from different taxonomic groups were screened to determine whether copper adsorption to the cell membrane was influenced by biotic factors, such as the ultrastructure of cell walls and cell size. Minutocellus polymorphus was the most sensitive species to copper and Dunaliella tertiolecta the least sensitive, with 72-h IC50 values (concentration to inhibit growth-rate by 50%) of 0.6 and 530 microg Cu/L, respectively. Copper solution-cell partition coefficients at equilibrium (K(d)) were calculated for six species of algae on a per cell and surface area basis. The largest and smallest cells had the lowest and highest K(d) values, respectively (on a surface area basis), with a general (non-linear) trend of decreasing K(d) with increasing cell surface area (p=0.026), however, no relationship was found between K(d) and copper sensitivity, nor cell size and copper sensitivity. Interspecies differences in copper sensitivity were not related to cell size, cell wall type, taxonomic group or K(d) values. The differences in sensitivity may be due to differences in uptake rates across the plasma membrane, in internal binding mechanisms and/or detoxification mechanisms between the different microalgal species. 相似文献
102.
Chambless Dianne L.; Bryan Angela D.; Aiken Leona S.; Steketee Gail; Hooley Jill M. 《Canadian Metallurgical Quarterly》1999,11(1):67
Confirmatory factor analysis was used to explore a 3-factor model of expressed emotion (Criticism, Emotional Overinvolvement, and Positivity) in a sample of 104 outpatients with agoraphobia or obsessive-compulsive disorder and 104 relatives of these patients. Multiple methods of measurement included the Camberwell Family Interview, observation of verbal and nonverbal behaviors during patient–relative problem-solving interactions, and ratings of relatives' behavior made by patients and by relatives. The convergent validity of the 3 individual constructs was demonstrated through single-factor models fitted to Criticism, Positivity, and Emotional Overinvolvement measures. A 3-factor model was then estimated and determined to provide adequate fit to the data, thus demonstrating the distinctiveness of the constructs. Criticism and Positivity were strongly and negatively correlated, whereas Emotional Overinvolvement bore little relationship to the other 2 factors. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
103.
The relationship of expressed emotion (EE) to behavior therapy outcome for obsessive-compulsive disorder (n?=?60) and panic disorder with agoraphobia (n&=?41) was investigated. Relatives' emotional overinvolvement and hostility predicted higher rates of treatment dropout. Higher hostility, as assessed by the Camberwell Family Interview (CFI), was related to poorer outcome for target ratings and for the Social Adjustment Scale; higher perceived criticism was also predictive of worse response on target ratings. In contrast, nonhostile criticism on the CFI was associated with better outcome on the behavioral avoidance test. In general, the relationship of EE to outcome was not moderated by type of relative, diagnosis, amount of contact with the relative, or use of psychotropic medication. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
104.
Contemporary urban theory raises many questions about how ‘the urban’ is being conceptualized in a fast changing world that is approaching an urban epoch. Evolving debates about what it means to be urban, including the similarities and differences between so-called northern and southern cities, the future of cities, the way to manage and sustain cities, and cities’ relationships to the new Urban Agenda and the Sustainable Development Goals, reveal the need for urban theory that can explain and provide insights into contemporary urban governance, processes, and outcomes. This special issue uses Durban as a lens to provide insight into the changing nature of cities in the Global South and Africa in particular, which encapsulate and reflect both formality and informality; tradition and modernity; uneven and unequal growth and social transformation; environmental crises and ‘resilience and sustainability’. This paper reflects on the dominant processes shaping the development of the city, revealing the challenges, tensions, and opportunities that emerge as the city assembles new ways of being urban, through the rationalities, knowledge, experiences, practices and actions of the state, citizens, and the private sector. 相似文献
105.
Twenge Jean M.; Baumeister Roy F.; Tice Dianne M.; Stucke Tanja S. 《Canadian Metallurgical Quarterly》2001,81(6):1058
Social exclusion was manipulated by telling people that they would end up alone later in life or that other participants had rejected them. These manipulations caused participants to behave more aggressively. Excluded people issued a more negative job evaluation against someone who insulted them (Experiments 1 and 2). Excluded people also blasted a target with higher levels of aversive noise both when the target had insulted them (Experiment 4) and when the target was a neutral person and no interaction had occurred (Experiment 5). However, excluded people were not more aggressive toward someone who issued praise (Experiment 3). These responses were specific to social exclusion (as opposed to other misfortunes) and were not mediated by emotion. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
106.
107.
A review of studies of cognitive-behavioral therapy (CBT) for generalized anxiety disorder, panic disorder with and without agoraphobia, and social phobia indicates that CBT is consistently more effective than waiting-list and placebo control groups. In general, CBT has proved more beneficial than supportive therapy as well. Comparisons with active behavioral treatments provide more variable results. Converging evidence suggests that cognitive change may be a strong predictor of treatment outcome, but that such change may be produced by a number of therapeutic approaches. Pretest–posttest change with CBT is depicted in meta-analytic summary form for each disorder. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
108.
Since the early 1980's, intelligent and adaptive systems have appeared and have been written about in a variety of guises. Although there are many differences between such systems as adaptive user interfaces, intelligent help systems and explanation systems, there are many similarities as well. The most notable of these is that they all require user models to be maintained and exploited as part of their designs. Furthermore, they share the same high level architecture. This paper discusses the use of models in human-computer interaction design and offers a common architecture for these adaptive systems. A methodology for the development of these systems is presented.This is based on our experimental work which is reported fully in Jennings, Benyon and Murray, 1991 and Jennings and Benyon, in press) 相似文献
109.
Involving users in expert system development 总被引:3,自引:0,他引:3
Dianne C. Berry 《Expert Systems》1994,11(1):23-28
Abstract: The ultimate criterion of success for interactive expert systems is that they will be used, and used to effect, by individuals other than the system developers. A key ingredient of success in most systems is involving users in the specification and development of systems as they are being built. However, until recently, system designers have paid little attention to ascertaining user needs and to developing systems with corresponding functionality and appropriate interfaces to match those requirements. Although the situation is beginning to change, many developers do not know how to go about involving users, or else tackle the problem in an inadequate way. This paper discusses the need for user involvement and considers why many developers are still not involving users in an optimal way. It looks at the different ways in which users can be involved in the development process and describes how to select appropriate techniques and methods for studying users. Finally, it discusses some of the problems inherent in involving users in expert system development, and recommends an approach which incorporates both ethnographic analysis and formal user testing. 相似文献
110.
Abstract: Evaluation is crucial for improving expert system design and performance. This paper stresses the need for considering system evaluation throughout the development process. It highlights the importance of evaluating system usability and discusses key usability issues. A number of basic evaluation methods are described, including interviews, questionnaires, observation, system logging, user diaries, laboratory experiments and field trials. Finally, the paper looks at evaluating systems within organisations, and assessing other long term effects of expert systems. 相似文献