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Important Variations (important + variation)
Selected AbstractsSources and sediment yield from a rural catchment in humid temperate environment, northwest SpainEARTH SURFACE PROCESSES AND LANDFORMS, Issue 3 2010M. L. Rodríguez-Blanco Abstract A study was carried out on a rural catchment located in northwest Spain to examine the sediment yield from the catchment by measuring suspended sediments during rainfall events. Within the catchment regular surveys were conducted to obtain data on the suspended sediment sources. Important variations in sediment load were detected at event scale (0·3,21·0,Mg); some of these can be explained in terms of event size, antecedent conditions, rainfall distribution and soil surface erosion. To study the variables controlling suspended sediment yield during the events in the catchment, several event and pre-event variables were calculated for all events. The sediment load is strongly influenced by discharge variables. During the events discharge,suspended sediments were also analysed. When the soil surface was unprotected, the formation of rills and ephemeral gullies on agricultural land at the catchment head was an important source of suspended sediments in the catchment. Copyright © 2010 John Wiley & Sons, Ltd. [source] Curriculum-Context Knowledge: Teacher Learning From Successive Enactments of a Standards-Based Mathematics CurriculumCURRICULUM INQUIRY, Issue 2 2009JEFFREY MARTIN CHOPPIN ABSTRACT This study characterizes the teacher learning that stems from successive enactments of innovative curriculum materials. This study conceptualizes and documents the formation of curriculum-context knowledge (CCK) in three experienced users of a Standards-based mathematics curriculum. I define CCK as the knowledge of how a particular set of curriculum materials functions to engage students in a particular context. The notion of CCK provides insight into the development of curricular knowledge and how it relates to other forms of knowledge that are relevant to the practice of teaching, such as content knowledge and pedagogical content knowledge. I used a combination of video-stimulated and semistructured interviews to examine the ways the teachers adapted the task representations in the units over time and what these adaptations signaled in terms of teacher learning. Each teacher made noticeable adaptations over the course of three or four enactments that demonstrated learning. Each of the teachers developed a greater understanding of the resources in the respective units as a result of repeated enactments, although there was some important variation between the teachers. The learning evidenced by the teachers in relation to the units demonstrated their intricate knowledge of the curriculum and the way it engaged their students. Furthermore, this learning informed their instructional practices and was intertwined with their discussion of content and how best to teach it. The results point to the larger need to account for the knowledge necessary to use Standards-based curricula and to relate the development and existence of well-elaborated knowledge components to evaluations of curricula. [source] Delegating Differences: Bilateral Investment Treaties and Bargaining Over Dispute Resolution ProvisionsINTERNATIONAL STUDIES QUARTERLY, Issue 1 2010Todd Allee Bilateral investment treaties (BITs) have become the dominant source of rules on foreign direct investment (FDI), yet these treaties vary significantly in at least one important respect: whether they allow investment disputes to be settled through the International Centre for the Settlement of Investment Disputes (ICSID). Through the compilation and careful coding of the text of nearly 1,500 treaties, we identify systematic variation in "legal delegation" to ICSID across BITs and explain this important variation by drawing upon a bargaining framework. Home governments prefer and typically obtain ICSID clauses in their BITs, particularly when internal forces push strongly for such provisions and when they have significantly greater bargaining power than the other signatory. Yet some home governments are less likely to insist upon ICSID clauses if they have historical or military ties with the other government. On the other hand, although host governments are often hostile toward ICSID clauses, particularly when sovereignty costs are high, they are more likely to consent to such clauses when they are heavily constrained by their dependence on the global economy. Our findings have significant implications for those interested in FDI, legalization, international institutions, and interstate bargaining. [source] The impact of ethnicity on prospective functional outcomes from community-based psychosocial rehabilitation for persons with schizophreniaJOURNAL OF COMMUNITY PSYCHOLOGY, Issue 6 2001Elizabeth S. Phillips Ethnicity was examined for its relationship to prospective functional outcomes from community-based psychosocial rehabilitation for individuals with schizophrenia. Participants were 98 individuals diagnosed with schizophrenia or schizoaffective disorder who were admitted to two community-based psychosocial rehabilitation programs. Previous studies had established that these programs were effective in improving functional outcomes. Data on hospitalization, independent living, social, and work functioning were collected every 6 months for a period of 3 years. The results using hierarchical linear modeling revealed significant differences among non-minorities, African Americans, and Latinos in rehabilitative change over time in the domains of work and social functioning. Non-minorities achieved the greatest gains in both social and work functioning. African Americans showed little change in social functioning, but showed a decline in work functioning. In the domain of work, Latinos deteriorated more than African Americans, and this was most notable for Latino males. There were no cross-ethnic differences in independent living or hospitalization outcomes. Based on these findings, there is important variation among different ethnic groups in their response to psychosocial rehabilitation. Implications are discussed in terms of the need for culturally relevant rehabilitation methods, and for research on cultural constructs in community-based intervention studies. © 2001 John Wiley & Sons, Inc. [source] Constraint Respecters, Constraint Challengers, and Crisis Decision Making in Democracies: A Case Study Analysis of Kennedy versus ReaganPOLITICAL PSYCHOLOGY, Issue 6 2005Jonathan W. Keller Models linking domestic political constraints (audience costs, pressures for the diversionary use of force, democratic norms and institutions) to foreign policy behavior generally assume that leaders simply recognize and submit to constraints in their domestic environments,a strong structural argument. In contrast, research on political leadership and decision making suggests that leaders vary systematically in their orientations toward constraints: "constraint respecters" tend to internalize potential constraints, while "constraint challengers" are more likely to view them as obstacles to be overcome. This article develops an integrative theoretical framework that explicitly incorporates these insights and applies them to the domain of crisis decision making. After identifying leaders' expected orientations toward constraints via at-a-distance methods, the plausibility of hypotheses derived from this framework is examined through case studies that explore the decision-making processes employed by President Kennedy (a "constraint respecter") and President Reagan (a "constraint challenger") during international crises. The results suggest that there is important variation in how leaders perceive and respond to domestic constraints, and that leadership style is one,though not the only,important source of this variation. [source] Spatial variation in density and total size estimates in fragmented primate populations: the golden-crowned sifaka (Propithecus tattersalli)AMERICAN JOURNAL OF PRIMATOLOGY, Issue 1 2010Erwan Quéméré Abstract The golden-crowned sifaka (Propithecus tattersalli) is an endangered lemur species found only in the Daraina region, a very restricted area in north-eastern Madagascar. Its forest habitat is highly fragmented and expected to suffer from significant changes in the near future. The species is poorly known and only one census study, carried out in 2000, has ever been published. It is thus crucial to update the conservation status of the golden-crowned sifaka before major anthropogenic environmental changes take place. Using the line-transect approach, we estimated the species density in the main forest fragments located in both the peripheral and central parts of the distribution range, including both protected and unprotected areas. In parallel, we tried to determine whether an edge effect could be detected by comparing densities at different distances from the forest edges. We found important variation of sifaka densities among forest fragments. The total species abundance is thus difficult to determine, but we estimated that it is likely to be over 18,000, two to three times higher than previously thought. However, our data also suggested that most P. tattersalli live in forests located in the central part of the distribution range and that the estimated densities in the central part were high (>80 individuals/km2). Two forest fragments, found to host a large part of the total population, are currently outside the managed area and their incorporation to the managed area is strongly recommended. Lastly, as expected for a folivorous and not heavily hunted species, our results are consistent with the hypothesis that this species does not experience a clear edge effect, at least during the first half of the dry season. This could be due to a high resiliency to habitat fragmentation or to the fact that fragmentation has been going on for some time. Am. J. Primatol. 72:72,80, 2010. © 2009 Wiley-Liss, Inc. [source] Effusive Constrictive Pericarditis: 2D, 3D Echocardiography and MRI ImagingECHOCARDIOGRAPHY, Issue 10 2007Brian Zagol M.D. The entity of effusive constrictive pericarditis (ECP) combines clinical and echocardiographic features of pericardial effusion and constrictive pericarditis. We describe a case of ECP, of probable tuberculous etiology, with typical hemodynamic findings of pericardial constriction, which persisted after the pericardial effusion was drained. Thickening of parietal and visceral pericardium was seen on 2D and 3D echo, and on MRI. Two important variations of ECP,due to tuberculous and to staphylococcal etiology, respectively,show some important differences that are relevant to management of therapy. [source] Relaxing/straightening of Afro-ethnic hair: historical overviewJOURNAL OF COSMETIC DERMATOLOGY, Issue 1 2007Tania Cristina De Sá Dias MSc Summary Afro-ethnic hair, when compared with naturally straight hair, presents some important variations such as differences in diameter in many points of the thread, ellipsoidal threads, and low trend of hydrating the scalp thus turning the hair drier, because the natural sebum distribution is irregular along the thread. This kind of hair may be straightened through both chemical and thermal methods. Straightening is a chemical process by which excessively curly hair is straightened in an irreversible way. Generally, the products used are formulated in a cosmetic emulsion with high pH. In this review, we present the historical development of hair straightening or relaxing through the evolution of the product categories. [source] Spatial distribution of leaf water-use efficiency and carbon isotope discrimination within an isolated tree crownPLANT CELL & ENVIRONMENT, Issue 10 2001X. Le Roux Abstract The spatial variations in the stable carbon isotope composition (,13C) of air and leaves (total matter and soluble sugars) were quantified within the crown of a well-watered, 20-year-old walnut tree growing in a low-density orchard. The observed leaf carbon isotope discrimination (,) was compared with that computed by a three-dimensional model simulating the intracanopy distribution of irradiance, transpiration and photosynthesis (previously parameterized and tested for the same tree canopy) coupled to a biophysically based model of carbon isotope discrimination. The importance of discrimination associated with CO2 gradients encountered from the substomatal sites to the carboxylation sites was evaluated. We also assessed by simulation the effect of current irradiance on leaf gas exchange and the effect of long-term acclimation of photosynthetic capacity and stomatal and internal conductances to light regime on intracanopy gradients in ,. The main conclusions of this study are: (i) leaf , can exhibit important variations (5 and 8, in total leaf material and soluble sugars, respectively) along light gradients within the foliage of an isolated tree; (ii) internal conductance must be taken into account to adequately predict leaf ,, and (iii) the spatial variations in , and water-use efficiency resulted from the short-term response of leaf gas exchange to variations in local irradiance and, to a much lesser extent, from the long-term acclimation of leaf characteristics to the local light regime. [source] Why Are Fewer Women than Men Elected?POLITICAL STUDIES REVIEW, Issue 2 2010Gender, the Dynamics of Candidate Selection Why are fewer women than men elected? Research suggests that this is the combined result of: (1) the supply of female aspirants, or the qualifications of women as a group to run for political office; and (2) the demand for female aspirants, or the preference of political elites for male over female candidates. The aim of this article is to reassess this explanation through the lens of recent case studies of female representation in four regions of the world: Africa, Latin America, North America and Western Europe. On their own, each contribution lends support to arguments about either supply or demand, leading their authors to offer distinct recommendations for change: an increase in the number of women who come forward, which is likely to be a slow and difficult process, or the adoption of gender quotas, which are quick but may produce mixed results. Yet juxtaposing these studies also exposes the limits of the traditional supply and demand model of candidate selection. On the one hand, the ,political market' does not operate efficiently towards an equilibrium solution of supply and demand. Rather, ideologies of gender introduce important distortions to the process: the fact that women are under-represented in all countries around the world suggests that both the supply of and demand for female candidates is artificially repressed, leading to low numbers of women in elective office. On the other hand, important variations exist in women's descriptive representation across countries and across political parties. These differences suggest that dynamics of supply and demand are shaped in crucial ways by features of the broader political context, which may include structural conditions but also the emergence of new and sometimes unanticipated opportunities. [source] Disparities in Drug Use and Disorder: Comparison of Two American Indian Reservation Communities and a National SampleAMERICAN JOURNAL OF ORTHOPSYCHIATRY, Issue 1 2007Nancy Rumbaugh Whitesell PhD Population-based samples provided estimates of drug use and disorder in two American Indian populations. Comparison to a national sample revealed tribal-national, intertribal, and intratribal gender and age differences. Findings suggest that disparities in drug use and disorder are complex, characterized by important variations across diverse American Indian tribal cultures. [source] Factors affecting pollination ecology of Quercus anemophilous species in north-west SpainBOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 3 2005F. J. RODRÍGUEZ-RAJO Pollination ecology of Quercus is influenced by meteorological, biotic and genetic factors. This study was undertaken to ascertain the effect induced by these factors on pollen production, release and dispersion. Aerobiological data have been used in recent years as phenological information, because the presence of pollen in the air is the result of flowering across a wide area. The onset of the Quercus pollen season and the atmospheric pollen concentrations during the pollination period in two localities of north-west Spain (Ourense and Santiago) were determined from 1993 to 2001. There were important variations in total annual pollen as a result of meteorological conditions, lenticular galls produced by Neuropterus on catkins and biennial genetic rhythms of pollen production. In order to determine the beginning of flowering, a thermal time model has been used. Chill requirements were around 800 chilling hours (CH) and heat requirements were 953 growth degree days (GDD in °C) in Santiago and 586 GDD in Ourense. Pollen in the air show positive correlation (99% significance) with daily thermal oscillation, maximum and minimum temperatures, and hours of sunshine. Regression analysis with previous days' pollen concentrations explained the high percentage of pollen concentration variability, as meteorological variables do not, on their own, explain pollen production and release. © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society, 2005, 149, 283,297. [source] Donor age and gestational age influence on growth factor levels in human amniotic membraneACTA OPHTHALMOLOGICA, Issue 6 2010Maria J. López-Valladares Acta Ophthalmol. 2010: 88: e211,e216 Abstract. Purpose:, Amniotic membrane (AM) is used as a biomaterial for reconstruction in ocular surface surgery. This study investigated the influence of interdonor variations and processing and preservation procedures applied to the AM on growth factors and protein levels. Methods:, Samples of human AM from thirteen donors were analysed. Collected donor data were age, parity and gestational age. Total protein amount was measured in extracts of intact AM nonpreserved, lyophilized and cryopreserved, at ,80°C and in liquid nitrogen. An enzyme-linked immunosorbent assay (ELISA) was used to assay growth factors protein levels for epidermal growth factor, basic fibroblast growth factor (bFGF), hepatocyte growth factor (HGF), keratinocyte growth factor (KGF), transforming growth factor beta1 (TFG-,1) and nerve growth factor (NGF). Univariate and multivariate statistical analyses were used to study the influence of the preservation method applied and interdonor variations on growth factors levels. Results:, We detected important variations in growth factors and protein concentrations between samples from different donors. Total protein amount, bFGF, HGF, KGF and TGF-,1 showed lower levels in samples from donors with higher gestational ages and donor ages, for all groups. Conclusion:, The variability in the biochemical composition of AM from different donors is considerable, and it is related with donor factors as donor age and gestational age. As AM biochemical composition has a role in its therapeutic effects, these variations could affect the clinical results of amniotic membrane transplantation and must be taken into account in donor selection processes. [source] Surgically important variations of the jugular veinsCLINICAL ANATOMY, Issue 6 2006B. Satheesha Nayak Abstract Knowledge of variations of veins of head and neck in relation to external jugular, anterior jugular, internal jugular, and facial veins is important to surgeons doing head and neck surgery as well as to radiologists doing catheterization and to clinicians in general. In the current case, multiple variations in the veins of the left side of neck are reported. The anterior division of retromandibular vein was absent. The facial vein continued as anterior jugular vein. The internal jugular vein was duplicated above the level of hyoid bone. There was a large communicating vein between the anterior jugular vein and anterior division of internal jugular vein. Lingual vein drained into the communicating vein. Jugular venous arch was abnormally large, doubled, and highly placed. The veins of the right side were normal. Clin. Anat. 19:544,546, 2006. © 2005 Wiley-Liss, Inc. [source] | ||||||||||||||||