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891.
Two-year chronic bioassays were conducted by using B6C3F1 female mice fed several concentrations of two different mixtures of coal tars from manufactured gas waste sites or benzo(a)pyrene (BaP). The purpose of the study was to obtain estimates of cancer potency of coal tar mixtures, by using conventional regulatory methods, for use in manufactured gas waste site remediation. A secondary purpose was to investigate the validity of using the concentration of a single potent carcinogen, in this case benzo(a)pyrene, to estimate the relative risk for a coal tar mixture. The study has shown that BaP dominates the cancer risk when its concentration is greater than 6,300 ppm in the coal tar mixture. In this case the most sensitive tissue site is the forestomach. Using low-dose linear extrapolation, the lifetime cancer risk for humans is estimated to be: Risk < 1.03 x 10(-4) (ppm coal tar in total diet) + 240 x 10(-4) (ppm BaP in total diet), based on forestomach tumors. If the BaP concentration in the coal tar mixture is less than 6,300 ppm, the more likely case, then lung tumors provide the largest estimated upper limit of risk, Risk < 2.55 x 10(-4) (ppm coal tar in total diet), with no contribution of BaP to lung tumors. The upper limit of the cancer potency (slope factor) for lifetime oral exposure to benzo(a)pyrene is 1.2 x 10(-3) per microgram per kg body weight per day from this Good Laboratory Practice (GLP) study compared with the current value of 7.3 x 10(-3) per microgram per kg body weight per day listed in the U.S. EPA Integrated Risk Information System.  相似文献   
892.
A critical review of Bourdieu’s theory of the state is developed here against the backdrop of both his wider theoretical project and empirical studies. Elaborating the concepts of symbolic capital, symbolic violence, and symbolic domination, the centrality that Bourdieu accords to symbolic forms is compared to benchmark Weberian accounts that start with the state monopoly of violence. Reviewing also some of the burgeoning secondary literature discussing his theory of the state, Bourdieu’s writings, which encompass various antinomies, are shown to vacillate between two distinct perspectives—a strong and a weak theory of the state. His rejection of the “physicalist” approaches of Marx, Elias, and Tilly is elaborated and subject to a counter-critique, particularly in relation to the notion of symbolic “violence.” Bourdieu’s account of the state is shown to be as much a political as theoretical intervention. His antagonism towards Marxist accounts in particular is shown to be rooted in a pragmatic interest in the role of the “left hand of the state” in progressive reform; and this perspective is traced back to the twin influences of Durkheim and Hegel, French republicanism, and in particular the potential of the state to express a universal interest. At the same time, compared with sophisticated Marxist and Weberian accounts and the work of Norbert Elias and Gramsci, Bourdieu’s theory is shown to be severely lacking in the way that he deals with violence and coercion. His “expanded materialism,” particularly with the “strong theory,” bends the stick too far and overplays the symbolic basis of consent. Nevertheless, Bourdieu’s insights with regard to the pervasive influences of state practices of classification, taxonomy, delegation, and naming are shown to have real utility with regard to focused empirical investigations of the state in modern societies.  相似文献   
893.
894.
Three experiments investigated the role of prosodic structure for infants' recognition of embedded word sequences. Six‐month‐olds were familiarized with 2 versions of the same sequence, 1 corresponding to a well‐formed prosodic unit and the other to a prosodically ill‐formed sequence (although a successive word series). Next, infants heard 2 test passages. One included the well‐formed unit, and the other included the ill‐formed sequence. In Experiment 1, infants listened longer to the passage containing the well‐formed unit, suggesting that such units, even when they are embedded, are better recognized. Experiments 2 and 3 showed that this better recognition does not depend on an acoustic match between the familiarized sequences and their later embeddings. This suggests that the advantage of the well‐formed unit is at least partially due to infants' use of prosody to parse continuous speech.  相似文献   
895.
A German version of the Organizational Citizenship Behavior Questionnaire (GOCBQ) is developed and tested. Study 1 was conducted with 150 students working together in 39 project groups. The results show that the internal consistency and test-retest-reliability of the GOCBQ are good. Moreover, the GOCBQ measures a general altruism orientation which can be interpreted as a stable trait. The GOCBQ does neither correlate substantially with demographical variables nor with extroversion or neuroticism. Instead, substantial correlations are registered with mood and group atmosphere. In study 2 results from study 1 were cross-validated with data from 128 voluntary and professional helpers, in study 3 with data from 43 professionals. Implications for future research and applications in working life are discussed.  相似文献   
896.
897.
Empirically estimated demand systems frequently fail to satisfy the appropriate theoretical curvature conditions. We propose and estimate two demand systems for which these conditions can be imposed globally; the first is derived from a normalized quadratic reciprocal indirect utility function and the second is derived from a normalized quadratic expenditure function. The former is flexible if there are no restrictions on its free parameters, but loses flexibility if the curvature conditions need to be imposed. The latter is flexible, in the class of functions satisfying local money metric scaling, even if the curvature conditions need to be imposed.  相似文献   
898.
The article presents a conceptual framework for the planning and control system in materials management. By an empirical analysis, three phases of development of the planning and control system in materials management are derived. These are related significantly with the kind of materials management. The main influencing factors are quality of management, quality of controlling, importance of materials management, and importance of the goals of materials management.  相似文献   
899.
900.
Abstract

The transition from student to social worker is a process which social work educators cannot control but can facilitate. Through classroom and field instruction faculty assumer responsibility of preparing students' professional knowledge, skills, and values; however, our responsibilities should extend beyond curriculum delivery. Drawing on Schlossberg's (1984) model of transitions, this article discusses two primary factors which affect the younger student in transition—developmental needs and the external environment—and strategies for assisting in the transition through intervention in academic advising and teaching roles.  相似文献   
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