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New Explanation (new + explanation)
Selected AbstractsThe river domain: why are there more species halfway up the river?ECOGRAPHY, Issue 2 2006Robert R. Dunn Biologists have long noted higher levels of species diversity in the longitudinal middle-courses of river systems and have proposed many explanations. As a new explanation for this widespread pattern, we suggest that many middle-course peaks in richness may be, at least in part, a consequence of geometric constraints on the location of species' ranges along river courses, considering river headwaters and mouths as boundaries for the taxa considered. We demonstrate this extension of the mid-domain effect (MDE) to river systems for riparian plants along two rivers in Sweden, where a previous study found a middle-course peak in richness of natural (non-ruderal) species. We compare patterns of empirical richness of these species to null model predictions of species richness along the two river systems and to spatial patterns for six environmental variables (channel width, substrate fineness, substrate heterogeneity, ice scour, bank height, and bank area). In addition, we examine the independent prediction of mid-domain effects models that species with large ranges, because the location of their ranges is more constrained, are more likely to produce a mid-domain peak in richness than are species with small ranges. Species richness patterns of riparian plants were best predicted by models including both null model predictions and environmental variables. When species were divided into large-ranged and small-ranged groups, the mid-domain effect was more prominent and the null model predictions were a better fit to the empirical richness patterns of large-ranged species than those of small-ranged species. Our results suggest that the peak in riparian plant species richness in the middle courses of the rivers studied can be explained by an underlying mid-domain effect (driven by geometric constraints on large-ranged species), together with environmental effects on richness patterns (particularly on small-ranged species). We suggest that the mid-domain effect may help to explain similar middle-course richness peaks along other rivers. [source] INEQUALITY, REDISTRIBUTION, AND RENT-SEEKINGECONOMICS & POLITICS, Issue 3 2004Francisco Rodríguez This paper presents a non-median voter model of redistribution in which greater inequality leads to lower redistribution. Bargaining between interest groups and politicians over exemptions implies that individuals with sufficiently high income will not pay taxes in equilibrium. Therefore, voters will set tax rates low enough so as to control the incentives for rent-seeking. An increase in inequality, by putting more income in the hands of individuals that can buy exemptions, will lead to lower equilibrium redistribution. The model can be used to account for a negative relationship between inequality and growth and provides a new explanation of why the poor do not expropriate the rich in democracies. [source] Dynamic Collapse Mechanisms in Metal Foam ExpansionADVANCED ENGINEERING MATERIALS, Issue 6 2010Dirk Lehmhus Abstract The study provides insight into decomposition of titanium hydride as foaming agent for powder metallurgically produced aluminum foams. Decomposition is characterized using thermal and kinetic analysis, allowing prediction of decomposition reactions. Such predictions are made for various time,temperature cycles, which are experimentally evaluated in parallel foaming experiments. A new explanation of foam collapse is derived from the results, which interprets hints at a maximum gas release rate, limiting maximum expansion, in terms of the existence of a maximum cell wall stretching rate and expanding foam can sustain. Thus a dynamic collapse criterion is added to existing static ones. [source] The British Electoral System, 1885-1970HISTORICAL RESEARCH, Issue 181 2000Peter Catterall At a time when the electoral system is coming under renewed scrutiny, this article examines the origins and creation of the present system in 1884-5, and its subsequent survival. This is the first such analysis to draw upon Public Record Office and party archives. Whilst showing that the political classes have been quite prepared to consider the merits of alternatives, particularly S.T.V., for Ireland or in colonial settings, they have usually been seen as less appropriate for Westminster. In exploring why that should be the case this article seeks to provide a new explanation for the longevity of the electoral arrangements of 1885. [source] Information technology innovation diffusion: an information requirements paradigmINFORMATION SYSTEMS JOURNAL, Issue 3 2008Nigel Melville Abstract., Information technology (IT) innovation research examines the organizational and technological factors that determine IT adoption and diffusion, including firm size and scope, technological competency and expected benefits. We extend the literature by focusing on information requirements as a driver of IT innovation adoption and diffusion. Our framework of IT innovation diffusion incorporates three industry-level sources of information requirements: process complexity, clock speed and supply chain complexity. We apply the framework to US manufacturing industries using aggregate data of internet-based innovations and qualitative analysis of two industries: wood products and beverage manufacturing. Results show systematic patterns supporting the basic thesis of the information processing paradigm: higher IT innovation diffusion in industries with higher information processing requirements; the salience of downstream industry structure in the adoption of interorganizational systems; and the role of the location of information intensity in the supply chain in determining IT adoption and diffusion. Our study provides a new explanation for why certain industries were early and deep adopters of internet-based innovations while others were not: variation in information processing requirements. [source] An analytical solution of one-dimensional consolidation for soft sensitive soil groundINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 9 2004Yun-Min Chen Abstract An analytical solution of one-dimensional consolidation for soft sensitive soil ground is presented. The moving boundary is introduced to indicate the notable change of consolidation behaviour of sensitive soil with the increase of stress level. It is assumed that the soil structure of the upper subsoil gradually destroys downwards with the dissipation of pore pressure, and the coefficient of consolidation as well as the coefficient of permeability of the upper subsoil become small, which hinders the dissipation of pore pressure of the lower subsoil. The consolidation degree curve obtained from the present solution is found to lie between the two curves obtained from Terzaghi one-dimensional consolidation solution with the parameters of the undisturbed soil and the remolded soil. The calculated results provide a new explanation for a general phenomenon in the consolidation of soft sensitive soil ground, as that for high loadings the consolidation is longer than for small ones. It should be pointed out from this study that both the deep mixing method and the long vertical drains methods are effective techniques for improving deep sensitive soil ground. Copyright © 2004 John Wiley & Sons, Ltd. [source] Intravenous Bisphosphonate Therapy Increases Radial Width in Adults With Osteogenesis Imperfecta,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 8 2005Davide Gatti Abstract Neridronate therapy in adult patients with OI significantly increases the cross-sectional area of the proximal radius. This observation may provide an additional explanation for the antifracture efficacy of bisphosphonates. Introduction: Bisphosphonate therapy decreases by 70-90% the fracture risk in patients with osteogenesis imperfecta (OI). This decrease is somewhat greater than that expected from the BMD changes, supporting the hypothesis that bisphosphonate therapy is associated with structural changes, not detectable by BMD measurements. Materials and Methods: To explore this hypothesis, pQCT measurements at the nondominant radius were obtained in a group of adult OI patients participating in a randomized clinical trial with neridronate. Results: The total volumetric BMD of the ultradistal radius rose significantly in patients treated with neridronate and calcium + vitamin D (neridronate group) compared with patients treated with calcium + vitamin D alone (control group). No significant differences were observed in trabecular BMD and in volumetric cortical density in either group. In the neridronate group, the cross-sectional area rose significantly versus both baseline values and the control group. These latter changes were associated with ,20% increases in bending breaking resistance index (BBRI). Conclusion: Our observation, if extended to postmenopausal osteoporosis, may provide a new explanation for the fracture risk reduction observed in osteoporotic patients treated with bisphosphonates. [source] Dispersal limitation may result in the unimodal productivity-diversity relationship: a new explanation for a general patternJOURNAL OF ECOLOGY, Issue 1 2007MEELIS PÄRTEL Summary 1Variation in diversity with habitat productivity has long been a central ecological topic. Plant diversity is mostly highest at intermediate productivity, exhibiting the unimodal (so-called ,hump-back') relationship. This relationship has been explained by both evolutionary and ecological processes, but the potential role of dispersal limitation has not been considered. 2We used European flora data to show that dispersal limitation may contribute to the unimodal productivity-diversity relationship. Species were characterized by their habitat productivity preference and dispersal probability (determined by the number of seeds and the presence of a dispersal syndrome). We calculated average relative dispersal probabilities for species assemblages occurring preferentially in different habitat productivity levels. 3At low productivity levels, species without dispersal syndromes predominate (R2 = 0.89), but at high productivity levels, species with a low number of seeds are common (R2 = 0.89). The total relative dispersal probability, combining both the dispersal probabilities attributable to the number of seeds and to the presence of dispersal syndrome, had a unimodal relationship with habitat productivity (R2 = 0.86). Thus, the unimodal productivity-diversity relationship may arise due to the minimal dispersal limitation of local richness in conditions of moderately low productivity. At very low productivity, the lack of dispersal syndromes may limit dispersal. At high productivity, the low number of seeds may limit dispersal. 4Consequently, in conditions where species pool size and biotic interactions do not vary along productivity gradients, the variation in dispersal probabilities with productivity alone can produce unimodal relationships between diversity and productivity. Thus, dispersal limitation may contribute to the observed diversity pattern and ecosystem functioning to a greater extent than usually assumed. [source] Culture and Identity-Protective Cognition: Explaining the White-Male Effect in Risk PerceptionJOURNAL OF EMPIRICAL LEGAL STUDIES, Issue 3 2007Dan M. Kahan Why do white men fear various risks less than women and minorities? Known as the "white-male effect," this pattern is well documented but poorly understood. This article proposes a new explanation: identity-protective cognition. Putting work on the cultural theory of risk together with work on motivated cognition in social psychology suggests that individuals selectively credit and dismiss asserted dangers in a manner supportive of their cultural identities. This dynamic, it is hypothesized, drives the white-male effect, which reflects the risk skepticism that hierarchical and individualistic white males display when activities integral to their cultural identities are challenged as harmful. The article presents the results of an 1,800-person study that confirmed that cultural worldviews interact with the impact of gender and race on risk perception in patterns that suggest cultural-identity-protective cognition. It also discusses the implications of these findings for risk regulation and communication. [source] Effect of miRNA-10b in regulating cellular steatosis level by targeting PPAR-, expression, a novel mechanism for the pathogenesis of NAFLDJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 1 2010Lin Zheng Abstract Background and Aim:, Accumulating evidence supports the effects of miRNA in lipid metabolism, providing a potential linkage between certain miRNA and non-alcoholic fatty liver disease (NAFLD). We aimed to investigate the miRNA expression pattern in a steatotic L02 cell model and explore the function of certain miRNA target pairs. Methods:, The cell model was established by culturing L02 cells with a high concentration of free fatty acid. Micro-array and stem-loop reverse transcription polymerase chain reaction (RT,PCR) were utilized to detect dysregulated miRNA, whereas computational algorithms were used for target prediction. Real time RT,PCR, Western blot, luciferase activity measurement, and other techniques were employed for target verification. Results:, Seventeen upregulated and 15 downregulated miRNA were found in steatotic L02 cells, while miRNA-10b was proven to regulate the steatosis level. Peroxisome proliferator-activated receptor-, (PPAR-,) was also found to participate in steatosis, as its protein level was decreased in steatotic L02 cells and its overexpression by transfection into the PPAR-,,pcDNA 3.1 vector could partially alleviate steatosis. We further found that PPAR-, is the direct target of miRNA-10b as it showed significantly changed protein expression, but a relatively unchanged mRNA level in steatotic L02 cells transfected with pre-miRNA-10b and anti-miRNA-10b. Moreover, the action of miRNA-10b on PPAR-, depends on the presence of a single miRNA-10b binding site, as the activity of a luciferase reporter carrying the mutant PPAR-, 3,-untranslated region was not reduced by the expression of miRNA-10b. Conclusion:, The established miRNA profile of the steatotic L02 cell model and the novel effect of miRNA-10b in regulating hepatocyte steatosis may provide a new explanation of the pathogenesis of NAFLD. [source] Between Hermes and Themis: An Empirical Study of the Contemporary Judiciary in SingaporeJOURNAL OF LAW AND SOCIETY, Issue 4 2001Ross Worthington Drawing upon interviews in 1995 and 1998 and analyses of judicial appointments from 1975,1998, the article offers a new explanation of judicial-executive relations in Singapore. It attempts to explain how the judiciary in Singapore actually functions, partly by using the concept of the core executive to locate the judiciary more accurately within its political context. The study demonstrates that the judicial system has been hegenomized by a number of political and bureaucratic strategies, and interprets its role in terms of the overall goals of the political executive. The lower judiciary is an amateur judiciary and forms part of the executive government. Despite this, the contemporary superior judiciary is not wholly a creature of the political executive, as is often postulated, but rather the result of a compromise which balances the need for a reputable judiciary with the requirement by the political executive for the judicial system to assist with the control of political opposition. This negotiated balance is qualitatively different from the relationship that characterized that between the Lee Kuan Yew governments and their Supreme Courts until 1991 and reflects the maturing of hegemonic control strategies under Goh Chok Tong. The analysis was completed in 1999. [source] Alkyl halides reactions with cathodes or with magnesium.JOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 12 2006Grignard reagent studied with radical clocks. Abstract In the mechanism of reaction of Grignard reagent formation for alkyl halides (RX), it is generally assumed that the alkyl radical, formed by the electron transfer from the metal to this halide, reacts rapidly with the paramagnetic MgX, species. The previous comparisons of aryl halides reactivity toward magnesium and their reactivity toward a cathode strongly suggested that MgX, species are not, for the aryl halides, compulsory to rationalise the observed facts. The aryl radicals formed by electron transfer from the metal to the aryl halide would undergo a rapid second electron transfer to yield carbanions transformed into RMgX by reaction with MgX2. In contrast, for the alkyl halides, the reduction of the rapidly formed alkyl radicals into carbanions has seldom been discussed as a possible fate for these radicals, the main discussed fates being dimerisation, disproportionation, hydrogen abstraction from the solvent, rearrangement or coupling with MgX, radicals. Two main differences distinguish the reactivity of alkyl halides from their aryl halides counterpart. First, the radical anions of aryl halides may have a given lifetime whereas electron transfer to alkyl halides is concerted with the cleavage of the molecule. Second, the aryl radicals display far stronger oxidising properties than the alkyl radicals. The counterpart of this property is that aryl carbanions display weaker reducing properties than the alkyl ones. In this report, putting in perspective Grignard reaction and the experimental results obtained with identical radical clocks in electrochemistry, we tentatively provide an answer to the question raised in the title. The comparison of electrochemical patterns of reactivity of selected alkyl halides and the evolutions of yields in the preparation of Grignard reagent suggest a new explanation for the lower yields generally observed when alkyl iodides are the starting substrates. It involves an autocatalytic reaction where carbanionic species formed from the alkyl radicals and diffusing away from the metal surface, transfer one electron to the alkyl halide; the result would be the creation of two radicals leading to an increased amount of by-products. If the carbanionic mechanism were to be retained for the formation of alkyl Grignard reagent one would have to admit that the magnesium surface behaves as a cathode displaying high current densities reminiscent of microelectrodes. Copyright © 2006 John Wiley & Sons, Ltd. [source] Enhancement of Lysosomal Osmotic Sensitivity Induced by the Photooxidation of Membrane Thiol Groups,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 2 2002Feng-Yi Wan ABSTRACT The osmotic lysis of photodamaged lysosomes is a critical event for killing tumor cells. How the photodamage increases lysosomal osmotic sensitivity is still unclear. In this work, the effect of the photooxidation of membrane thiol groups on the lysosomal osmotic sensitivity was studied by measuring the thiol groups with 5,5,-dithio-bis(2-nitrobenzoic acid) and examining the lysosomal ,-hexosaminidase latency loss in a hypotonic sucrose medium. The results show that methylene blue,mediated photooxidation of lysosomes decreased their membrane thiol groups and produced cross-linkage of membrane proteins (molecular weight ranging from 75,000 to 125,000), which was visualized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Simultaneously, the lysosomal osmotic sensitivity increased. These photoinduced alterations of the lysosomes could be recovered by reducing the oxidized thiol groups with dithiothreitol. It indicates that the photooxidation of membrane thiol groups can increase the lysosomal osmotic sensitivity and therefore provides a new explanation for the photoinduced lysosomal lysis. [source] COMMERCIAL ACTIVITY AS INSURANCE: THE INVESTMENT BEHAVIOUR OF NON-PROFIT ORGANIZATIONSANNALS OF PUBLIC AND COOPERATIVE ECONOMICS, Issue 3 2010John Bennett ABSTRACT,:,We provide a new explanation for commercial activities by non-profit organizations whose primary concern is to supply mission output. Starting from the observation that donations to individual non-profits are often highly volatile, we show how investment in commercial activity can constitute a form of insurance for mission activity. Although investment in commercial activity has an opportunity cost in terms of capacity to produce mission output, if donations turn out to be low the commercial revenue will enable cross-subsidization of mission output. The equilibrium commercial investment is (weakly) positively related to the degree of risk aversion. [source] The effects of income, education and age on healthHEALTH ECONOMICS, Issue 8 2007Olga Kiuila Abstract We use the core interviews of the US Health Interview Survey for the years 1987,1994, to study the effects of socioeconomic status (SES) on mortality and self-reported health. We find, consistent with previous studies, that the relationship between mortality and indicators such as education and income diminishes with age. We consider new explanations for this result and conclude that general biological deterioration at old age is probably the principal one. One important piece of evidence for this conclusion is the finding that there is no relationship at all between mortality and SES for people whose self-reported health status at baseline is either fair or poor. Copyright © 2007 John Wiley & Sons, Ltd. [source] Rethinking an old empirical puzzle: econometric evidence on the forward discount anomalyJOURNAL OF APPLIED ECONOMETRICS, Issue 6 2001Professor Alex Maynard Using both semiparametric and parametric estimation methods, this paper corroborates earlier findings of fractionally integrated behaviour in the forward premium. Two new explanations are also proposed to help reconcile earlier conflicting empirical evidence on the time series properties of the forward premium. Traditional regression approaches used to test the forward rate unbiasedness hypothesis are then evaluated, including regression in levels, in returns (Fama's, 1984, regression), and in error-correction format. Interesting statistical and/or interpretive implications are found in all three cases. For example, the predictions of the appropriate nonstandard limit theory are consistent with many of the standard empirical results reported from Fama's regression, including the commonly occurring, yet puzzling negative correlations between spot returns and the forward premium. It is suggested that the principal failure of unbiasedness, may be due instead to the difference in persistence between these two series. Copyright © 2001 John Wiley & Sons, Ltd. [source] Noah and Disaster Planning: The Cultural Significance of the Flood StoryJOURNAL OF CONTINGENCIES AND CRISIS MANAGEMENT, Issue 4 2003Russell R. Dynes Disasters are both interesting and infrequent. Thus, understanding them usually depends on stories others tell us. Such stories frame our understandings and imaginations. With those stories at hand, we comprehend reality and history on the basis of what everyone knows. At times, however, it is useful to examine what everyone knows. To create a lasting narrative, disaster provides rich raw material to elaborate. ,Natural' disasters involve universal, primordial elements , water, fire, the shaking of the earth. Beyond those physical elements, disasters elicit basic human concerns , death, injury, disruption, broken social relationships, and fractured hope. Ultimate values and meanings can be challenged. Continuity and permanence are challenged. Such crises can lead to new explanations and the reworking of old metaphors. The task here is to take a disaster story, the Biblical flood , often referred to as the Deluge , and to examine its origins, its evolution, and its continuing impact within the Western World. More specifically, it will be argued that the flood story has had a continuing determinative influence on how disasters have been imagined in American society, especially in the ways that imagery has influenced emergency planning. [source] Understanding challenging behaviour in people with severe and profound intellectual disability: a stress-attachment modelJOURNAL OF INTELLECTUAL DISABILITY RESEARCH, Issue 6 2002C. G. C. Janssen Abstract Background Advances in our knowledge of attachment, stress and coping may foster new explanations for the development of challenging behaviour in people with intellectual disability (ID). Method Research on stress and coping among people with ID was reviewed initially, and then studies on the security of the attachment relationships of people with ID with their caregivers were analysed. Results There is evidence that people with ID are more vulnerable to stress and use less effective coping strategies. Furthermore, the body of studies on attachment indicates that people with ID are at risk for developing insecure, especially disorganized attachment. There is evidence from other populations that the combination of stress, and insecure or disorganized attachment may put people at risk for developing behaviour problems. Conclusion A stress-attachment model of the development of challenging behaviour among people with ID shows promise as an explanatory framework. The uncovering of these developmental mechanisms may be particularly useful for the prevention of behavioural problems. [source] Reflective verbalization improves solutions,the effects of question-based reflection in design problem solvingAPPLIED COGNITIVE PSYCHOLOGY, Issue 2 2004Annekatrin Wetzstein In this experimental study (N=60), the impact of question-based reflective verbalization on the quality of a design solution was investigated. Participants first designed an everyday object (garden grill) using various design strategies and then either answered questions of a naive partner, where they had to verbally describe, explain, justify and evaluate their solution (experimental group), or were given a filler task (control group). After the intervention, participants continued their design. The improvement in the design quality was significantly larger for the experimental group than for the control group. Significantly more participants of the experimental group developed new principles and added new explanations of functions to their design, whereas in the control group only corrections were made. We suggest that the dialogue specific style of reflective verbalization in the experimental group is linked to a specific way of thinking which is important for solving complex problems. Copyright © 2004 John Wiley & Sons, Ltd. [source] | ||||||||||||||||||||||