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Common Assumption (common + assumption)
Selected AbstractsShadow-Experiences and the Phenomenal Structure of ColorsDIALECTICA, Issue 2 2010René Jagnow It is a common assumption among philosophers of perception that phenomenal colors are exhaustively characterized by the three phenomenal dimensions of the color solid: hue, saturation and lightness. The hue of a color is its redness, blueness or yellowness, etc. The saturation of a color refers to the strength of its hue in relation to gray. The lightness of a color determines its relation to black and white. In this paper, I argue that the phenomenology of shadows forces us to consider illumination as an additional dimension of phenomenal colors. For this purpose, I will first introduce two different interpretations of shadow-experiences, which Chalmers has called the simple and the complex interpretations, and show that they both fail to account for important phenomenal facts about shadow-experiences. I will then introduce my own alternative interpretation based on the idea that illumination is a dimension of phenomenal colors and explain how it can account for these facts. [source] Opposing effects of competitive exclusion on the phylogenetic structure of communitiesECOLOGY LETTERS, Issue 9 2010Margaret M. Mayfield Ecology Letters (2010) 13: 1085,1093 Abstract Though many processes are involved in determining which species coexist and assemble into communities, competition is among the best studied. One hypothesis about competition's contribution to community assembly is that more closely related species are less likely to coexist. Though empirical evidence for this hypothesis is mixed, it remains a common assumption in certain phylogenetic approaches for inferring the effects of environmental filtering and competitive exclusion. Here, we relate modern coexistence theory to phylogenetic community assembly approaches to refine expectations for how species relatedness influences the outcome of competition. We argue that two types of species differences determine competitive exclusion with opposing effects on relatedness patterns. Importantly, this means that competition can sometimes eliminate more different and less related taxa, even when the traits underlying the relevant species differences are phylogenetically conserved. Our argument leads to a reinterpretation of the assembly processes inferred from community phylogenetic structure. [source] Applying species-sensitivity distributions in ecological risk assessment: Assumptions of distribution type and sufficient numbers of species,ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2000Michael C. Newman Abstract Species-sensitivity distribution methods assemble single-species toxicity data to predict hazardous concentrations (HCps) affecting a certain percentage (p) of species in a community. The fit of the lognormal model and required number of individual species values were evaluated with 30 published data sets. The increasingly common assumption that a lognormal model best fits these data was not supported. Fifteen data sets failed a formal test of conformity to a lognormal distribution; other distributions often provided better fit to the data than the lognormal distribution. An alternate bootstrap method provided accurate estimates of HCp without the assumption of a specific distribution. Approximate sample sizes producing HC5 estimates with minimal variance ranged from 15 to 55, and had a median of 30 species-sensitivity values. These sample sizes are higher than those suggested in recent regulatory documents. A bootstrap method is recommended that predicts with 95% confidence the concentration affecting 5% or fewer species. [source] A Combined Theoretical and Experimental Research Project into the Aminolysis of ,-Lactam Antibiotics: The Importance of Bifunctional CatalysisEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 21 2003Natalia Díaz Abstract This paper reports the results of experimental work on the aminolysis of penicillin (6-APA) and monobactam (aztreonam) antibiotics by propylamine or ethanolamine. In general, aztreonam is slightly more reactive than 6-APA, despite the common assumption that the amide bond should be less activated in monobactams. Intriguingly, when ethanolamine acts as the nucleophile, the corresponding rate law has a kinetic term proportional to [RNH2][RNH3+]. To complement the experimental observations, the rate-determining free energy barriers in aqueous solution for various mechanistic pathways were computed by standard quantum chemical methodologies. From previous theoretical work it was assumed that the aminolysis of ,-lactams proceeds through mechanisms in which either a water molecule or a second amine molecule may act as bifunctional catalysts, assisting proton transfer from the attacking amine molecule to the leaving amino group. The energy barriers as computed have moderate values (ca. 26,34 kcal·mol,1) and reproduce most of the experimentally observed kinetic trends. Furthermore, the calculations predict that positively charged ethanolamine molecules can act as bifunctional catalysts as well, thus explaining the presence of the kinetic term proportional to [RNH2][RNH3+] in the rate law. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] The dynamics of collapse in world fisheriesFISH AND FISHERIES, Issue 2 2005Christian Mullon Abstract The fear of a rapid depletion of world fish stocks because of over-exploitation is increasing. Analysis of 1519 main series of the FAO world fisheries catch database over the last 50 years reveals that 366 fisheries' collapses occurred, that is nearly one fishery of four. The robustness of this result is tested by performing several complementary analyses using different conservative options. The number of collapses has been stable through time since 1950s indicating no improvement in the overall fisheries management. Three typical patterns emerge from the analysis of catch series during the period preceding the collapses: smooth collapse (33%), i.e. a long regular decline, erratic collapse (45%), i.e. a fall after several ups and downs, and a plateau-shaped collapse (21%), i.e. a sudden fall after a relatively long and stable persistence of high level of catches. Using a simple mathematical model, we relate the plateau-shaped collapses (which are, by nature, the most difficult to predict) to surreptitiously increasing exploitation and a depensatory mechanism at low population levels. Thus, a stable level of catch over several years is shown to conceal the risk of a sudden collapse. This jeopardizes the common assumption that considers the stability of catch as a goal for fisheries sustainability. [source] Pumping-Induced Drawdown and Stream Depletion in a Leaky Aquifer SystemGROUND WATER, Issue 2 2007James J. Butler Jr The impact of ground water pumping on nearby streams is often estimated using analytic models of the interconnected stream-aquifer system. A common assumption of these models is that the pumped aquifer is underlain by an impermeable formation. A new semianalytic solution for drawdown and stream depletion has been developed that does not require this assumption. This solution shows that pumping-induced flow (leakage) through an underlying aquitard can be an important recharge mechanism in many stream-aquifer systems. The relative importance of this source of recharge increases with the distance between the pumping well and the stream. The distance at which leakage becomes the primary component of the pumping-induced recharge depends on the specific properties of the aquifer, aquitard, and streambed. Even when the aquitard is orders of magnitude less transmissive than the aquifer, leakage can be an important recharge mechanism because of the large surface area over which it occurs. Failure to consider aquitard leakage can lead to large overestimations of both the drawdown produced by pumping and the contribution of stream depletion to the pumping-induced recharge. The ramifications for water resources management and water rights adjudication can be significant. A hypothetical example helps illustrate these points and demonstrates that more attention should be given to estimating the properties of aquitards underlying stream-aquifer systems. The solution presented here should serve as a relatively simple but versatile tool for practical assessments of pumping-induced stream-aquifer interactions. However, this solution should not be used for such assessments without site-specific data that indicate pumping has induced leakage through the aquitard. [source] Diagnostic evaluation of conceptual rainfall,runoff models using temporal clusteringHYDROLOGICAL PROCESSES, Issue 20 2010N. J. de Vos Abstract Given the structural shortcomings of conceptual rainfall,runoff models and the common use of time-invariant model parameters, these parameters can be expected to represent broader aspects of the rainfall,runoff relationship than merely the static catchment characteristics that they are commonly supposed to quantify. In this article, we relax the common assumption of time-invariance of parameters, and instead seek signature information about the dynamics of model behaviour and performance. We do this by using a temporal clustering approach to identify periods of hydrological similarity, allowing the model parameters to vary over the clusters found in this manner, and calibrating these parameters simultaneously. The diagnostic information inferred from these calibration results, based on the patterns in the parameter sets of the various clusters, is used to enhance the model structure. This approach shows how diagnostic model evaluation can be used to combine information from the data and the functioning of the hydrological model in a useful manner. Copyright © 2010 John Wiley & Sons, Ltd. [source] An enhanced constitutive model for crushable granular materialsINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 6 2010Ali Daouadji Abstract Studies in the past have tried to reproduce the mechanical behaviour of granular materials by proposing constitutive relations based on a common assumption that model parameters and parameters describing the properties, including gradation of individual grains are inevitably linked. However successful these models have proved to be, they cannot account for the changes in granular assembly behaviour if the grains start to break during mechanical loading. This paper proposes to analyse the relation between grading change and the mechanical behaviour of granular assembly. A way to model the influence of grain breakage is to use a critical state-based model. The influence of the amount of grain breakage during loading, depending on the individual grain strength and size distribution, can be introduced into constitutive relations by means of a new parameter that controls the evolution of critical state with changes in grain size distribution. Experimental data from a calcareous sand, a quartz sand, and a rockfill material were compared with numerical results and good-quality simulations were obtained. The main consequences of grain breakage are increased compressibility and a gradual dilatancy disappearance in the granular material. The critical state concept is also enriched by considering its overall relation to the evolution of the granular material. Copyright © 2009 John Wiley & Sons, Ltd. [source] Democracy and Diversionary Military Intervention: Reassessing Regime Type and the Diversionary HypothesisINTERNATIONAL STUDIES QUARTERLY, Issue 1 2005Jeffrey Pickering This article concentrates on two limitations in the literature on diversionary force. First is the common assumption that major powers are the only actors capable of diversion. Second is the narrow conceptualization of regime type prevalent in the literature. Instead of dichotomizing regimes, we distinguish mature democracies and autocracies from consolidating variants of these regimes. We draw hypotheses from the institutional approach and test them with time series cross-section negative binomial first-order autoregressive process estimates of 140 countries from 1950 to 1996. We find that not all democracies and not all autocracies divert. Mature democracies, consolidating autocracies, and transitional polities are the only regime types prone to this type of force. Our results suggest that the diversionary literature would benefit from more discriminating operationalizations of regime type and by looking beyond major powers to the actions of less powerful states. [source] Who Are the Uninsured Elderly in the United States?JOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 4 2004James W. Mold MD Because of the Medicare program, a common assumption is made that virtually all older Americans have health insurance coverage. Data from the 2000 National Health Interview Survey were analyzed to estimate the number of people aged 65 and older without health insurance; their stated reasons for being uninsured; and the associations between lack of insurance and sociodemographic variables, health status, and access to and use of healthcare services. In 2000, there were approximately 350,000 older Americans with no health insurance. Those without insurance were more likely to be younger, Hispanic, nonwhite, unmarried (widowed, divorced, or never married), poor, and foreign-born. They were less likely to hold U.S. citizenship. Despite relatively high rates of chronic medical conditions, they were unlikely to receive outpatient or home healthcare services. The most common reason given for lack of insurance was its cost. This study reveals important gaps in the availability of health insurance for the elderly, gaps that are likely to affect an increasing number of older Americans in the coming decade. [source] Are Aggressive Treatment Strategies Less Cost-Effective for Older Patients?JOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 4 2001Aggressive Care for Patients with Acute Respiratory Failure, The Case of Ventilator Support OBJECTIVES: A common assumption is that life-sustaining treatments are much less cost-effective for older patients than for younger patients. We estimated the incremental cost-effectiveness of providing mechanical ventilation and intensive care for patients of various ages who had acute respiratory failure. DESIGN: Retrospective analysis of data on acute respiratory failure from Study to Understand Prognoses and Preferences for Outcomes and Risks of Treatments (SUPPORT). SETTING: Acute hospital. PARTICIPANTS: 1,005 with acute respiratory failure; 963 received ventilator support and 42 had ventilator support withheld. MEASUREMENTS: We studied 1,005 patients enrolled in a five-center study of seriously ill patients (SUPPORT) with acute respiratory failure (pneumonia or acute respiratory distress syndrome and an Acute Physiology Score ,10) requiring ventilator support. For cost-effectiveness analyses, we estimated life expectancy based on long-term follow-up of SUPPORT patients and estimated utilities (quality-of-life weights) using time-tradeoff questions. We used hospital fiscal data and Medicare data to estimate healthcare costs. We divided patients into three age groups (<65, 65,74, and ,75 years); for each age group, we performed separate analyses for patients with a ,50% probability of surviving at least 2 months (high-risk group) and those with a> 50% probability of surviving at least 2 months (low-risk group). RESULTS: Of the 963 patients who received ventilator support, 44% were female; 48% survived 6 months; and the median (25th, 75th percentile) age was 63 (46, 75) years. For the 42 patients for whom ventilator support was withheld, the median survival was 3 days. For low-risk patients (>50% estimated 2-month survival), the incremental cost (1998 dollars) per quality-adjusted life-year (QALY) saved by providing ventilator support and aggressive care increased across the three age groups ($32,000 for patients age <65, $44,000 for those age 65,74, and $46,000 for those age ,75). For high-risk patients, the incremental cost-effectiveness was much less favorable and was least favorable for younger patients ($130,000 for patients age <65, $100,000 for those age 65,74, and $96,000 for those age ,75). When we varied our assumptions from 50% to 200% of our baseline estimates in sensitivity analyses, results were most sensitive to the costs of the index hospitalization. CONCLUSIONS: For patients with relatively good short-term prognoses, we found that ventilator support and aggressive care were economically worthwhile, even for patients 75 years and older. For patients with poor short-term prognoses, ventilator support and aggressive care were much less cost-effective for adults of all ages. [source] What controls woodland regeneration after elephants have killed the big trees?JOURNAL OF APPLIED ECOLOGY, Issue 1 2009Stein R. Moe Summary 1Top-down regulation of ecosystems by large herbivores is a topic of active debate between scientists and managers, and a prime example is the interaction between elephants Loxodonta africana and trees in African savannas. A common assumption among wildlife managers is that a local reduction in elephant numbers will ultimately allow woodland to self-restore to a desired former state. Such regeneration is, however, dependent on the survival of seedlings of impacted tree species. We conducted a field experiment to investigate seedling predation in the elephant-transformed Chobe riparian woodland of northern Botswana. 2We planted seedling gardens in (i) complete exclosures that excluded all herbivores except small rodents and invertebrates, (ii) semi-permeable exclosures that excluded ungulates but included primates, lagomorphs, all rodents, gallinaceous birds, etc, and (iii) completely open plots. Seedlings were of two tree species decreasing in the area (Faidherbia albida and Garcinia livingstonei) and two that are increasing (Combretum mossambicense and Croton megalobotrys). 3After 9 months, seedling survival ranged from >75% for all species in the complete exclosure to <20% for Faidherbia albida in the open plots. Survival of all seedlings except C. megalobotrys declined precipitously in open plots during the dry season when invertebrates are largely dormant but when impalas Aepyceros melampus (locally abundant ungulates) increase the browse components of their diets. 4Seedling survival in the open plots was negatively related to local impala density but unrelated to that of any other browser. 5Synthesis and applications. Our findings relate to the current debate about managing elephants to restore southern African savanna landscapes to desired historical states. Various seedling predators, including the ubiquitous impala Aepyceros melampus, regulate the regeneration of trees from seedlings, and our experiments support the hypothesis that tall closed-canopy woodlands originate during episodic windows of opportunity for seedling survival. To artificially recreate such a window would require the decimation of seedling predators as well as elephants, which is impractical at the landscape scale. [source] Editors' Introduction: Birds and AgricultureJOURNAL OF APPLIED ECOLOGY, Issue 5 2000S.J. Ormerod 1.,Around 10% of recent papers in the Journal of Applied Ecology have examined interactions between birds and agriculture. This statistic reveals the important role now played by ecologists in assessing the effects of agricultural development worldwide. It also reflects the position of birds as both indicators and targets of agricultural change: their patterns of behaviour, distribution, seasonal phenology and demography track closely onto the spatial and temporal scales of agricultural intensification. 2.,Papers in this Special Profile illustrate how research in this sphere has shifted towards assessing the processes by which birds are affected ecologically by agricultural change. The works examine spatial patterns in extinction; assess long-term trends in bird abundance and agricultural practice; reveal how foraging and breeding performance in farmland birds varies between habitats; and evaluate the role of large-scale modelling in examining hypotheses about the influences of land management on birds. The final paper shows that birds can have intrinsically positive value in agricultural systems. 3.,All the papers propose management prescriptions for agricultural areas that blend the microscopic , for example, how to modify local land structure to benefit birds , and the macroscopic , for example, by suggested inputs into land-use policy. Perhaps most pertinent is the key conclusion that agricultural change is multivariate, so that straightforward univariate effects on birds are unlikely. Restoration of impacted populations might therefore require holistic strategies that encourage appropriately scaled agricultural extensification. Success would be most likely if farmers, conservationists and other key players were engaged collaboratively in the process. 4.,Current ideas about restoring farmland bird populations share a common assumption: if agricultural practice has reduced populations hitherto, then agricultural practice can restore the losses. We suggest that this assumption carries a range of predictions that now require testing through sustainable farm management , a situation ideally suited to ,BACI' style experiments. 5.,We reiterate the need to expand work on other groups of organisms affected negatively or positively by agricultural management to allow a broader perspective of impacts or benefits. [source] The White,Coat Effect: Physician Attire and Perceived Authority, Friendliness, and AttractivenessJOURNAL OF APPLIED SOCIAL PSYCHOLOGY, Issue 12 2004Gary L. Brase Although previous studies have evaluated the effects of attire on doctor,patient interaction, the common assumption of a tradeoff between perceptions of medical authority/ status versus trustworthiness/openness has not been established. Thirty,eight male and 40 female participants rated their perceptions of same, and opposite,gender models who all were identified as doctors, but who were wearing different attire. The results indicate that authority and trust are not opposing factors and that a white coat and formal attire are clearly superior to casual attire. Additionally, perceptions of attractiveness of same, and opposite,gender doctors were rated, finding gender differences in perceptions different from, but theoretically similar to, prior findings. For females rating male models, perceptions of authority and attractiveness appear to be related. [source] Politically Motivated Reinforcement Seeking: Reframing the Selective Exposure DebateJOURNAL OF COMMUNICATION, Issue 4 2009R. Kelly Garrett This article seeks to reframe the selective exposure debate by demonstrating that people exhibit a preference for opinion-reinforcing political information without systematically avoiding opinion challenges. The results are based on data collected in a national random-digit-dial telephone survey (n = 1,510) conducted prior to the 2004 U.S. presidential election. Analyses show that Americans use the control afforded by online information sources to increase their exposure to opinions consistent with their own views without sacrificing contact with other opinions. This observation contradicts the common assumption that reinforcement seeking and challenge avoidance are intrinsically linked aspects of the selective exposure phenomenon. This distinction is important because the consequences of challenge avoidance are significantly more harmful to democratic deliberation than those of reinforcement seeking. Politically Motivated Reinforcement Seeking: Reframing the Debate Over Selective Exposure in the Political Domain This article seeks to reframe the selective exposure debate by demonstrating that people exhibit a preference for opinion-reinforcing political information without systematically avoiding opinion challenges. The results are based on data collected in a national randomdigit-dial telephone survey (n = 1,510) conducted prior to the 2004 U.S. presidential election. Analyses show that Americans use the control afforded by online information sources to increase their exposure to opinions consistent with their own views without sacrificing contactwith other opinions. This observation contradicts the common assumption that reinforcement seeking and challenge avoidance are intrinsically linked aspects of the selective exposure phenomenon. This distinction is important because the consequences of challenge avoidance are significantly more harmful to democratic deliberation than those of reinforcement seeking. Politisch motivierte Suche nach Verstärkung: Eine Umdeutung der Debatte zur selektiven Wahrnehmung in der Politik Dieser Artikel versucht, die Debatte zur selektiven Wahrnehmung umzudeuten, indem er aufzeigt, dass Menschen eine Präferenz für meinungsverstärkende politische Informationen zeigen, ohne systematisch zu vermeiden, dass ihre Meinung hinterfragt wird. Diese Ergebnisse basieren auf Daten einer nationalen zufallsgesteuerten Telefonumfrage (n=1.510) die vor den U.S. Präsidentschaftswahlen 2004 durchgeführt wurde. Die Analysen zeigen, dass Amerikaner die Möglichkeiten von Online-Informationsquellen nutzen, um die Exposition zu konsistenten Meinungen herzustellen, ohne dafür andere Meinungen aufzugeben. Diese Beobachtung widerspricht der allgemeinen Annahme, dass Verstärkersuche und Herausforderungsvermeidung intrinsisch verbundene Aspekte des selektiven Wahrnehmungsphänomens sind. Diese Unterscheidung ist wichtig, weil die Konsequenzen der Vermeidung von Herausforderung für die demokratische Teilhabe wesentlich problematischer sind als die des Suchens nach Verstärkung. La Búsqueda del Reforzamiento Motivado Políticamente: Re-encuadrando el Debate sobre la Exposición Selectiva en el Dominio Político R. Kelly Garrett Resumen Este artículo busca re-encuadrar el debate sobre la exposición selectiva demostrando que la gente exhibe una preferencia por la opinión que refuerza la información política sin evadir sistemáticamente los desafíos de la opinión. Los resultados están basados en los datos colectados en una entrevista aleatoria de discado telefónico a nivel nacional (n = 1,510) conducida antes de la elección presidencial del 2004 de los EE.UU. Los análisis demuestran que los Estadounidenses usaron el control proporcionado por recursos de información online para incrementar la exposición a las opiniones consistentes con sus propios puntos de vista sin sacrificar el contacto con otras opiniones. Esta observación contradice la asunción común que la búsqueda del reforzamiento y la evasión del desafío están intrínsecamente unidos con los aspectos de la exposición selectiva del fenómeno. Esta distinción es importante porque las consecuencias de la evasión del desafío son significativamente más perjudiciales en la deliberación democrática que aquellas de la búsqueda del reforzamiento. [source] Measuring Knowledge Stocks: A Process of Creative DestructionKYKLOS INTERNATIONAL REVIEW OF SOCIAL SCIENCES, Issue 3 2005Jürgen Bitzer Summary This paper proposes a new method for constructing R&D capital stocks developed to avoid the common assumption of a constant rate of knowledge depreciation, which implies wear and tear of knowledge. The method models the development of R&D capital stocks as a process of creative destruction linking the depreciation of knowledge to the emergence of new knowledge. A first empirical assessment of the new method , measuring the influence of R&D capital stocks on production in the manufacturing sectors of 12 OECD countries , produces plausible and robust results. [source] The Value of Embedded Real Options: Evidence from Consumer Automobile Lease ContractsTHE JOURNAL OF FINANCE, Issue 1 2007CARMELO GIACCOTTO ABSTRACT Under the common assumption of constant interest rates, we show that penalties for early termination of a lease are often structured in such a way that the cancellation option embedded in consumer automotive leases has little value. Furthermore, our estimates drawn from a sample of three popular car models over 1990 to 2000 indicate that the stand-alone value of the lease-end purchase option is, on average, about 16% of the market value of underlying used vehicles, or about $1,462 per contract. Finally, we examine the sensitivity of our option value estimates to model parameters and default risk. [source] Commercial Insurance vs Community-based Health Plans: Time for a Policy Option With Clinical Emphasis to Address the Cost SpiralTHE JOURNAL OF RURAL HEALTH, Issue 2 2005Bruce Amundson MD ABSTRACT: The nation continues its ceaseless struggle with the spiraling cost of health care. Previous efforts (regulation, competition, voluntary action) have included almost every strategy except clinical. Insurers have largely failed in their cost-containment efforts. There is a strong emerging body of literature that demonstrates the relationship between various clinical strategies and reductions in utilization and costs. This article describes the organization of health services, including integration of delivery and financing systems, at the community level as a model that effectively addresses the critical structural flaws that have frustrated control of costs. Community-based health plans (CHPs) have been developed and have demonstrated viability. The key elements of CHPs are a legal organizational structure, a full provider network, advanced care-management systems, and the ability to assume financial risk. Common misconceptions regarding obstacles to CHP development are the complexity of the undertaking, difficulty assuming the insurance function, and insured pools that are too small to be viable. The characteristics of successful CHPs and 2 case studies are described, including the types of advanced care-management systems that have resulted in strong financial performance. The demonstrated ability of CHPs to establish financial viability with small numbers of enrollees challenges the common assumption that there is a fixed relationship between health plan enrollment size and financial performance. Organizing the health system at the community/regional level provides an attractive alternative model in the health-reformdebate. There is an opportunity for clinical systems and state and federal leaders to support the development of community-based integrated delivery and financing system models that, among other advantages, have significant potential to modulate the pernicious cost spiral. [source] FATHERS, SONS, AND THE STATE: Discipline and Punishment in a Wolof HinterlandCULTURAL ANTHROPOLOGY, Issue 1 2009DONNA L. PERRY ABSTRACT This essay builds on fieldwork in rural Senegal to examine three cases in which elder household heads called on gendarmes to physically discipline rebellious youths. These cases, which revolved around harsh acts of corporal punishment, invite inquiry into common assumptions about African families and states. The first assumption is the common dichotomy drawn between African youths, portrayed as modern and menacing, and African elders, portrayed as "traditional" and hence benign. The second assumption is the dichotomy drawn between the African family, conceived as solidary and nurturing, and the African state, conceived as alien and predatory. In examining these cases of discipline and punishment, this essay reveals the ever-shifting power relations that link Wolof household heads, dependent junior males, and state agents, and simultaneously introduces new questions about the morality of farmer,state relations and generational conflict. My analysis reveals the spatial geography of Senegal's youth crisis, which takes different forms in rural and urban locales. The anxiety of rural patriarchs is fed by a fear-mongering media obsessed with youthful anarchy in the cities, and a long-standing political rhetoric about the threat of rural out-migration. Elder men in the countryside, who experience diminishing household authority under neoliberalism, make proactive efforts to keep the urban youth crisis at bay. They seek to augment their domestic power by reestablishing links with a state that has long bolstered patriarchy but whose power is currently in decline. By lending patriarchs their coercive force, gendarmes attempt to accomplish through private, indirect means, what the postcolonial state is unable to do: maintain social order by reining in disruptive youths. The harsh disciplinary measures that gendarmes employ are not alien to Wolof culture, but integral to Wolof conceptions of child rearing. [source] The Illegal Way In and The Moral Way OutEUROPEAN JOURNAL OF PHILOSOPHY, Issue 2 2007Gerhard Øverland At the heart of the current debate about immigration we find a conflict of convictions. Many people seem to believe that a country has a right to decide who to let in and who to keep out, but quite often they appear equally committed to the view that it is morally wrong to expel someone from within the borders of their country if that would seriously jeopardise the person in question. While the first conviction leads to stricter border controls in an attempt to prevent would-be immigrants from entering the country illegally, the latter conviction ensures that aliens with a legitimate claim on protection will not be removed forcibly. It is not strange, therefore, that the task of pinning down a morally sound immigration policy is such an elusive enterprise. In this paper I take it for granted that no electorate would be prepared to accept the kind of policy they ought to, and that we in consequence will continue to let in as few immigrants as is currently the case. Given this constraint I argue against two common assumptions concerning a viable immigration policy. First, granted that certain conditions are satisfied, professional smugglers should not face legal sanctions for bringing asylum seekers to a potential host country. Second, countries that limit immigration should not treat people seeking family reunion preferentially or on a par with other immigrants, but rather act so as to maximise the number of refugees allowed to enter. [source] Beyond ethnic match: Effects of client,therapist cognitive match in problem perception, coping orientation, and therapy goals on treatment outcomesJOURNAL OF COMMUNITY PSYCHOLOGY, Issue 5 2005Nolan Zane This study examined the outcome effects of cognitive match between Asian and White outpatient clients and their therapists. Many clinicians believe that one hindrance to the treatment of ethnic minority clients is that therapists and clients may not share common assumptions and attitudes about therapy and about the problems that are presented in treatment. The study investigated client,therapist similarity in their perceptions of the presenting problem, coping orientation, and expectations about treatment goals. This study constituted a more rigorous test of the cognitive match hypotheses in that it was prospective in nature, used separate and independent sources for the cognitive predictors, employed multiple outcome measures, and focused on specific attitudes and perceptions that are quite salient and relevant to treatment. Cognitive match on treatment goals was predictive of session impact. Moreover, cognitive matches in avoidant coping orientation and in perceived distress associated with interpersonal problems were predictive of certain treatment outcomes. The findings may help explain why clients matched on ethnicity with their therapists tend to stay longer in treatment and do better in psychotherapy. © 2005 Wiley Periodicals, Inc. J Comm Psychol 33: 569,585, 2005. [source] A primer on classical test theory and item response theory for assessments in medical educationMEDICAL EDUCATION, Issue 1 2010André F De Champlain Context, A test score is a number which purportedly reflects a candidate's proficiency in some clearly defined knowledge or skill domain. A test theory model is necessary to help us better understand the relationship that exists between the observed (or actual) score on an examination and the underlying proficiency in the domain, which is generally unobserved. Common test theory models include classical test theory (CTT) and item response theory (IRT). The widespread use of IRT models over the past several decades attests to their importance in the development and analysis of assessments in medical education. Item response theory models are used for a host of purposes, including item analysis, test form assembly and equating. Although helpful in many circumstances, IRT models make fairly strong assumptions and are mathematically much more complex than CTT models. Consequently, there are instances in which it might be more appropriate to use CTT, especially when common assumptions of IRT cannot be readily met, or in more local settings, such as those that may characterise many medical school examinations. Objectives, The objective of this paper is to provide an overview of both CTT and IRT to the practitioner involved in the development and scoring of medical education assessments. Methods, The tenets of CCT and IRT are initially described. Then, main uses of both models in test development and psychometric activities are illustrated via several practical examples. Finally, general recommendations pertaining to the use of each model in practice are outlined. Discussion, Classical test theory and IRT are widely used to address measurement-related issues that arise from commonly used assessments in medical education, including multiple-choice examinations, objective structured clinical examinations, ward ratings and workplace evaluations. The present paper provides an introduction to these models and how they can be applied to answer common assessment questions. Medical Education 2010: 44: 109,117 [source] What does the stress-gradient hypothesis predict?OIKOS, Issue 10 2010Resolving the discrepancies In recent years the importance of facilitative interactions in ecological communities is increasingly recognized. This phenomenon has been observed repeatedly, particularly in vegetation communities, in a wide range of environmental conditions. The current hypothesis predicts that the role of facilitation becomes increasingly important in conjunction with increasing stress. Several empirical studies, however, failed to detect such patterns, particularly at the extreme ends of the stress gradients. Herein, we present a conceptual model that may resolve discrepancies between expected and observed and provides a more precise framework of the existing hypotheses. By relaxing two common assumptions commonly used by the stress-gradient hypothesis (SGH) we are able to demonstrate that under some circumstances the importance of facilitation may be less at the extreme ends of these gradients. Namely, we first re-emphasize the notion that physiological response is not linear with respect to environmental changes along stress gradients. Second, it is argued that the net outcome of facilitative and competitive interactions is reflected in the fitness of individuals as a product of these two processes, in contrast to the commonly applied assumption of additivity. Accordingly, a synthesis of the concepts of population biology (measures of fitness) and plant physiology (nonlinear responses) with the stress gradient hypothesis while retaining the original simplicity of the SGH model contributes to a better specification of the predictions of the stress-gradient hypothesis and the resolution of observed contradictions. [source] 7 A Cultural Critique of Cultural RelativismAMERICAN JOURNAL OF ECONOMICS AND SOCIOLOGY, Issue 1 2007Xiaorong Li This chapter explores a certain line of critical analysis according to which one can proceed to undermine the claim that judgments approving freedom, and standards upholding human rights, are culturally relativistic and cannot possibly have any universal validity. This exploration begins with a scrutiny of common assumptions about the nature of culture itself. The author tries to demonstrate that common misunderstandings of culture have provided ammunition to cultural relativists. Seeking clarity helps strengthen the philosophical objections to normative cultural relativism. The author refers to such a line of analysis as the "cultural critique of cultural relativism." [source] Analysing disruptive potential: the case of wireless local area network and mobile communications network companiesR & D MANAGEMENT, Issue 1 2005Stefan Hüsig In this article, we analyse the prediction that wireless local area network (W-LAN) technologies will be disruptive for incumbent mobile communications network operators. For this purpose, we develop a methodology of guided interviews to assess technologies for their disruptive characteristics based on theory of disruptive technology developed by Christensen (1997) and recent extensions. The application of our comprehensive step-by-step method improves the precision of the disruptive technology concept and its usability for practitioners to make ex ante distinctions between disruptive technologies and other phenomena caused by emerging technologies. Our method predicts that contrary to common assumptions, W-LAN is not likely to represent a disruptive technology for the established mobile communications network firms in terms of Christensen's concept. This research was conducted in close collaboration with Vodafone Pilotentwicklung, an R&D and technology monitoring unit of the Vodafone Group. Vodafone provided part of the empirical data through expert interviews and market reports. [source] What does the community think about lifespan extension technologies?AUSTRALASIAN JOURNAL ON AGEING, Issue 4 2006The need for an empirical base for ethical, policy debates Objectives:,This paper examines public understandings of possibilities for increasing life expectancy, interest in taking up lifespan-extending interventions, and motivations influencing these intentions. Methods:,Structured interviews were conducted with 31 adults, aged 50 and over. Results:,Participants believed that technological advances would increase life expectancy but questioned the value of quantity over quality of life. Life in itself was not considered valuable without the ability to put it to good use. Participants would not use technologies to extend their own lifespan unless the result would also enhance their health. Conclusions:,These findings may not be generalisable to the general public but they provide the first empirical evidence on the plausibility of common assumptions about public interest in ,anti-ageing' interventions. Surveys of the views of representative samples of the population are needed to inform the development of a research agenda on the ethical, legal and social implications of lifespan extension. [source] Attributional biases in subclinical depression: A schema-based accountCLINICAL PSYCHOLOGY AND PSYCHOTHERAPY (AN INTERNATIONAL JOURNAL OF THEORY & PRACTICE), Issue 1 2007Steven J. Morris Non-depressed individuals exhibit a self-serving attributional bias, taking more credit for success than for failure. Clinically and subclinically depressed people are less self-serving, often to the point of making similar attributions (explanations) for successes and failures. The present studies evaluated a schematic account of these distinct attributional biases. Subclinically depressed and non-depressed participants completed measures of attributional bias (the relative strength of ability attributions for success versus failure), schema-based optimism (the relative expectedness of success versus failure) and self-schemas of competence. Two studies evaluated a hypothesis derived from the schematic account: the greater the perceived competence and optimism, the more self-serving the attributional bias. As predicted, (a) attributional bias scores covaried with optimism and competence scores in both magnitude and valence (or direction), (b) depressed-non-depressed differences in attributional biases paralleled differences in competence and optimism and (c) when attributional bias scores were adjusted for the effects of optimism or competence, depressed,non-depressed differences in attributional biases were eliminated. The schematic account raises questions about the common assumptions that attributional patterns are traits, and that they play a central role in the aetiology and treatment of depression. Copyright © 2007 John Wiley & Sons, Ltd. [source] Limitations in predicting dyebath exhaustion using optical spectroscopyCOLORATION TECHNOLOGY, Issue 3 2010Melih Günay There are practical limitations in predicting dyebath concentrations and dyebath exhaustion using absorbance measurements from optical spectroscopy. The purpose of this paper is to examine the common assumptions of prediction models that cause prediction errors, and especially when multiple dye combinations are used. If a linear model is used to map absorbance to concentration, then five assumptions must hold: measurement repeatability, linear scaling, spectral additivity, linear independence of the constituent spectra and the absence of spectral morphing. Violation of one or more of these assumptions will lead to errors in predicting the concentrations of dyes in a dyebath and subsequent exhaustion calculations. [source] | ||||||||||||||||||||||||||||