There is increasing interest in the use of tiered approaches in risk assessment of mixtures or co-exposures to chemicals for prioritization. One possible screening-level risk assessment approach is the threshold of toxicological concern (TTC). To date, default assumptions of dose or response additivity have been used to characterize the toxicity of chemical mixtures. Before a screening-level approach could be used, it is essential to know whether synergistic interactions can occur at low, environmentally relevant exposure levels. Studies demonstrating synergism in mammalian test systems were identified from the literature, with emphasis on studies performed at doses close to the points of departure (PODs) for individual chemicals. This search identified 90 studies on mixtures. Few included quantitative estimates of low-dose synergy; calculations of the magnitude of interaction were included in only 11 papers. Quantitative methodology varied across studies in terms of the null hypothesis, response measured, POD used to test for synergy, and consideration of the slope of the dose-response curve. It was concluded that consistent approaches should be applied for quantification of synergy, including that synergy be defined in terms of departure from dose additivity; uniform procedures be developed for assessing synergy at low exposures; and the method for determining the POD for calculating synergy be standardized. After evaluation of the six studies that provided useful quantitative estimates of synergy, the magnitude of synergy at low doses did not exceed the levels predicted by additive models by more than a factor of 4.
David Kopp's book develops a model of chromatic chord relations in nineteenth-century music by composers such as Schubert, Beethoven, Chopin, Schumann and Brahms. The emphasis is on explaining chromatic third relations and the pivotal role they play in theory and practice. The book traces conceptions of harmonic system and of chromatic third relations from Rameau through nineteenth-century theorists such as Marx, Hauptmann and Riemann, to the seminal twentieth-century theorists Schenker and Schoenberg and on to the present day. Drawing on tenets of nineteenth-century harmonic theory, contemporary transformation theory and the author's own approach, the book presents a clear and elegant means for characterizing commonly acknowledged but loosely defined elements of chromatic harmony, and integrates them as fully fledged entities into a chromatically based conception of harmonic system. The historical and theoretical argument is supplemented by plentiful analytic examples.
This article is a reply to Hansen's (2012) call for the counseling profession to embrace a purely humanistic ideology for counseling. The authors suggest the relationship between humanities and science set forth by Hansen does not emphasize the both-and aspects of these ideologies.An integrative framework is considered for counseling.
In this conceptual paper, we consider organizational storytelling as a communications tool in which stories are used to reduce the stress and anxiety of organizational members during a crisis. While there is much consensus among organizational scholars detailing storytelling's active role in such processesas organizational learning and performance (Boje, 1991;Czarniawska, 1998), knowledge sharing and knowledge management (Denning, 2000), management development (Morgan & Dennehy, 1997), and normative organizational behavior (Poulton, 2005) When organizational storytelling scholars recently covened for their annual Organizational Storytelling Weekend in Washington, D.C., the symposium' s founder, Steve Denning, observed that for the first time, their meeting was taking place
In this article, I address the often lingering and multifaceted issues of trainer accountability, specifically, transfer of training. The significance of transfer came to light for me recently during my research in progress with certified diabetes educators. Because certified diabetes educators lack performance appraisal systems that memorialize their training effectiveness vis‐à‐vis diabetes education to the patient, undocumented feckless transfer of training here may not only equate to inefficiencies within the clinic but also may be linked to poor health outcomes and shorter life spans for the trainee‐patient.
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