bluuebunny/crossref_metadata_2025_split huggingface dataset:
BAYESIAN ANALYSIS OF VECTOR ARFIMA PROCESSES
Authors: Ravishanker Nalini , Ray Bonnie K. 
Published: February 2008

SummaryA general framework is presented for Bayesian inference of multivariate time series exhibiting long‐range dependence. The series are modelled using a vector autoregressive fractionally integrated moving‐average (VARFIMA) process, which can capture both short‐term correlation structure and long‐range dependence characteristics of the individual series, as well as interdependence and feedback relationships between the series. To facilitate a sampling‐based Bayesian approach, the exact joint posterior density is derived for the parameters, in a form that is computationally simpler than direct evaluation of the likelihood, and a modified Gibbs sampling algorithm is used to generate samples from the complete conditional distribution associated with each parameter. The paper also shows how an approximate form of the joint posterior density may be used for long time series. The procedure is illustrated using sea surface temperatures measured at three locations along the central California coast. These series are believed to be interdependent due to similarities in local atmospheric conditions at the different locations, and previous studies have found that they exhibit ‘long memory’ when studied individually. The approach adopted here permits investigation of the effects on model estimation of the interdependence and feedback relationships between the series.
NONPARAMETRIC AUTOCOVARIANCE FUNCTION ESTIMATION
Authors: Hyndman R.J. , Wand M.P. 
Published: February 2008

SummaryNonparametric estimators of autocovariance functions for non‐stationary time series are developed. The estimators are based on straightforward nonparametric mean function estimation ideas and allow use of any linear smoother (e.g. smoothing spline, local polynomial). The paper studies the properties of the estimators, and illustrates their usefulness through application to some meteorological and seismic time series.
Exploring the Etiology of Perfectionism and Perceptions of Self‐worth in Young Athletes
Authors: McArdle Siobhain , Duda Joan L. 
Published: February 2008

AbstractThis study assessed the main and interactive effects of perceived parental expectations and perceived parental criticism on 180 young talented athletes' perfectionistic tendencies and level and reported fluctuation in self‐esteem. A potential quadratic effect of perceived parental expectations on the targeted dependent variables was also tested. Moderated hierarchical regression analyses indicated that perceived parental criticism was the strongest predictor of concerns over mistakes and doubts about actions whereas perceived parental expectations were positively related to personal standards only. Self‐esteem was predicted by high perceived parental expectations and low perceived parental criticism. Children's reported fluctuation in self‐esteem was highest when perceived parental criticism was high and perceived parental expectations were deemed high or low. The results argue against a unidimensional and linear examination of factors relating to the etiology of perfectionism and perceptions of self‐worth.
Habitus and Homeland: Educational Aspirations, Family Life and Culture in Autobiographical Narratives of Educational Experience in Rural Wales
Authors: Baker Sally , Brown B.J. 
Published: February 2008

AbstractWe use the concept of habitus to illuminate the autobiographical narratives of participants from disadvantaged backgrounds in mid‐twentieth century rural Wales who were successful at university. The participants’ constructions of their habitus and aspirations drew upon a number of themes that intersected with their ideas of Welsh culture. Images of Welsh culture, history and national identity played a significant role in their accounts. The participants’‘aspirational habitus’ involved a rich blend of images and symbolic resources and a sense that they had a right to be at university. This has implications for how we conceive of habitus and its role in guiding people from rural to largely urban intellectual cultures. The participants’ experiences were made possible by virtue of the isolation of their rural communities and the corresponding significance of their social milieu, which consolidated their value system by attaching considerable significance to educational achievement.
Third‐Party Certification in the Global Agrifood System: An Objective or Socially Mediated Governance Mechanism?
Authors: Hatanaka Maki , Busch Lawrence 
Published: February 2008

AbstractThird‐party certification (TPC) is becoming an integral component of the global agrifood system. However, little is known about its functions, structures and practices. In this article we examine the emergence of TPC as a governance mechanism, its organisational structure, and its practices. Distinguishing between two forms of ‘independence’– organisational and operational – we argue that TPC exhibits organisational, but not operational independence. Thus, in contrast to the view of TPC as an objective governance mechanism, we argue that TPC is embedded in social, political and economic networks. This finding, we argue, raises questions as to how TPC is structured and operates, who gets to decide the ways it is structured and operates, and the ways that TPC might differentially impact on actors in the food and agricultural sector.
Gait choice in desert‐living black‐backed jackals
Authors: Goldenberg F. , Glanzl M. , Henschel J. R. , Funk S. M. , Millesi E. 
Published: February 2008

AbstractGait selection is a strategy used by quadrupeds to meet the demands of locomotion under variable environmental conditions. The movement of black‐backed jackals Canis mesomelas within a desert area was investigated. The usage and distribution of gaits in three distinct desert environments in the Namib Desert, Namibia, were analysed. The areas were chosen based on topographical differences: a bare, a featureless sand plain in an interdune valley, a large sand dune and a narrow dune valley with clumped plant growth. Fresh jackal tracks were recorded by GPS once a week for 1 year. Gait types, gait segment lengths and the rate of switches between gaits were analysed. Trot was the most frequently used gait in all areas, followed by walk and the two types of gallop. Jackals used faster gaits, with the lowest number of gait switches in the interdune plain. Movements on the sand dune were characterized by shorter gait segment lengths and frequent gait changes. In the dune valley, movements were slower and the rate of gait changes was intermediate between the other two areas. The strongest influence on gait choice and on gait changes was found to be the terrain topography, mainly the grade. Gait and track choice can be seen as a dynamic adaptation to a demanding environment like the Namib Desert.
Variation in anhydrobiotic survival of two eutardigrade morphospecies: a story of cryptic species and their dispersal
Authors: Faurby S. , Jönsson K. I. , Rebecchi L. , Funch P. 
Published: February 2008

AbstractStudies of geographic variation in anhydrobiotic tolerance may increase our understanding of the population dynamics of terrestrial meiofauna and the relative importance of local adaptation and microhabitat niche separation. Although anhydrobiosis in tardigrades has been studied extensively, few studies have dealt with intraspecific variation in survival and none of these included genetic data to validate the intraspecific nature of the comparisons. Such data are necessary when working with meiofauna as cryptic species are common. We analysed the anhydrobiotic survival and genetic variation in cytochrome oxidase subunit I of two eutardigrades (Richtersius coronifer and Ramazzottius oberhaeuseri) from Italy and Sweden to detect possible local adaptation. Survival was analysed as a multidimensional contingency table and showed that anhydrobiotic survival was higher in Sweden for Ra. oberhaeuseri whereas no significant geographic variation was found for Ri. coronifer. Our genetic analysis indicated the coexistence of two cryptic species of Ra. oberhaeuseri in Italy, only one of which was found in Sweden. It could not be determined whether the variation in Ramazzottius is intra‐ or interspecific due to the presence of these cryptic species. We suggest that geographic variation in anhydrobiotic survival may be a general phenomenon in tardigrades but further research is necessary to determine the degree of intraspecific variation. The genetic analysis showed indications of long‐term isolation of the individual populations of Ri. coronifer but recent dispersal in one of the cryptic species of Ramazzottius. We found higher survival in Ra. oberhaeuseri than in Ri. coronifer. These results indicate a possible coupling between anhydrobiotic survival and dispersal rate.
Brain heparanase expression is up‐regulated during postnatal development and hypoxia‐induced neovascularization in adult rats
Authors: Navarro Fabrice P. , Fares Raafat P. , Sanchez Pascal E. , Nadam Jérémie , Georges Béatrice , Moulin Colette , Morales Anne , Pequignot Jean‐Marc , Bezin Laurent 
Published: February 2008

AbstractHeparanase is an endo‐β‐d‐glucuronidase which specifically cleaves extracellular and cell surface heparan sulphates at intra‐chain sites. Its enzymatic activity is strongly implicated in cell dissemination associated with tumor metastasis and inflammation. Indeed, heparanase gene is expressed in various tumors and its over‐expression is correlated with increased tumor vascularity and metastatic potential of tumor cells. However, heparanase expression in non‐invasive and non‐immune tissue, including brain, has received less attention. Using RT‐qPCR, western blot and histological analysis, we demonstrate in the adult rat that heparanase transcript is differentially expressed according to brain area, and that heparanase protein is mainly detected in neurons. Furthermore, we provide evidence that heparanase transcript and protein reach their greatest levels at early postnatal stages, in particular within the neocortex characterized by intensive structural plasticity. Using the in vitro model of PC12‐induced neuronal differentiation, we suggest that developmental regulation of heparanase may coincide with axonal and dendritic pathfinding. At adulthood, we demonstrate that the increased heparanase transcript level correlates in the hippocampus with enhanced angiogenesis following repeated hypoxia exposures. Taken together, our results emphasize the potential importance of heparanase in brain homeostasis, both during development and adaptative responses to severe environmental challenges.
Modulation of adenosine A1 and A2A receptors in C6 glioma cells during hypoxia: involvement of endogenous adenosine
Authors: Castillo Carlos A. , León David , Ruiz María Angeles , Albasanz José Luis , Martín Mairena 
Published: February 2008

AbstractDuring hypoxia, extracellular adenosine levels are increased to prevent cell damage, playing a neuroprotective role mainly through adenosine A1 receptors. The aim of the present study was to analyze the effect of hypoxia in both adenosine A1 and A2A receptors endogenously expressed in C6 glioma cells. Two hours of hypoxia (5% O2) caused a significant decrease in adenosine A1 receptors. The same effect was observed at 6 h and 24 h of hypoxia. However, adenosine A2A receptors were significantly increased at the same times. These effects were not due to hypoxia‐induced alterations in cells number or viability. Changes in receptor density were not associated with variations in the rate of gene expression. Furthermore, hypoxia did not alter HIF‐1α expression in C6 cells. However, HIF‐3α, CREB and CREM were decreased. Adenosine A1 and A2A receptor density in normoxic C6 cells treated with adenosine for 2, 6 and 24 h was similar to that observed in cells after oxygen deprivation. When C6 cells were subjected to hypoxia in the presence of adenosine deaminase, the density of receptors was not significantly modulated. Moreover, DPCPX, an A1 receptor antagonist, blocked the effects of hypoxia on these receptors, while ZM241385, an A2A receptor antagonist, was unable to prevent these changes. These results suggest that moderate hypoxia modulates adenosine receptors and cAMP response elements in glial cells, through a mechanism in which endogenous adenosine and tonic A1 receptor activation is involved.
Inhibition of nucleolar transcription as a trigger for neuronal apoptosis
Authors: Kalita Katarzyna , Makonchuk Denys , Gomes Cynthia , Zheng Jing‐Juan , Hetman Michal 
Published: February 2008

AbstractIn post‐mitotic neurons, the mechanisms of the apoptotic checkpoint that is activated by DNA damage remain unclear. Here we show that in cultured cortical neurons, the DNA damaging agent camptothecin (CPT) reduced transcription of rRNA and disrupted nucleolar staining for B23/nucleophosmin suggesting DNA damage‐induced nucleolar stress. Although CPT activated the pro‐apoptotic protein p53, the CPT‐induced nucleolar stress was unaffected by p53 inhibition. In addition, brain‐derived neurotrophic factor‐mediated protection from CPT‐induced apoptosis prevented neither nucleolar stress nor p53 activation. Therefore, inhibition of rRNA transcription might be upstream of the pro‐apoptotic p53 activity. Indeed, short hairpin RNA‐mediated inhibition of a RNA‐Polymerase‐I co‐factor, transcription initiation factor IA, attenuated rRNA transcription causing nucleolar stress and p53‐dependent neuronal apoptosis. The protein synthesis inhibitor cycloheximide blocked apoptosis that was induced by over‐expressed shTIF‐IA or active form of p53. Also, the general transcription inhibitor actinomycin D triggered nucleolar stress and activated p53. However, it did not induce apoptosis except at the low concentration of 0.05 μg/mL with stronger inhibitory activity against nucleolar than extranucleolar transcription. Hence, nucleolar stress‐activated apoptosis requires extranucleolar transcription. This study identifies the nucleoli of post‐mitotic neurons as sensors of DNA damage coupling reduced rRNA transcription to p53‐mediated apoptosis that requires de novo expression of protein‐coding genes. Thus, rDNA selectivity of DNA damage may determine its ability to induce neuronal apoptosis.
Enhanced exercise‐induced plasma cytokine response and oxidative stress in COPD patients depend on blood oxygenation
Authors: Jammes Yves , Steinberg Jean Guillaume , Ba Abdoulaye , Delliaux Stéphane , Brégeon Fabienne 
Published: February 2008

SummaryIn healthy subjects, hypoxemia and exercise represent independent stressors promoting the exercise‐induced cytokine response and oxidative stress. We hypothesized that hypoxemia in patients with chronic obstructive pulmonary disease (COPD) may affect the cytokine production and/or the changes in oxidant–antioxidant status in response to maximal exercise. Exercise‐induced changes in PaO2 allowed to transiently increase or decrease baseline hypoxemia and to point out its specific action on muscle metabolism. COPD patients with severe to moderate hypoxemia (56 < PaO2 < 72 mmHg) performed an incremental cycling exercise until volitional exhaustion. Two cytokines [interleukin (IL)‐6 and tumour necrosis factor (TNF)‐α] and three blood indices of oxidative stress [plasma thiobarbituric acid reactive substances (TBARS) and two antioxidants, reduced erythrocyte glutathione (GSH), and reduced plasma ascorbic acid, RAA] were measured at rest, then during and after exercise. The changes in the cytokine levels and oxidant–antioxidant status were analysed in relation with the baseline PaO2 and its exercise‐induced variations. Data were compared with those obtained in an age‐ and body mass index‐matched group of healthy subjects. Compared with healthy subjects, COPD patients presented a marked accentuation of exercise‐induced increase in IL‐6 level and earlier changes in their oxidant–antioxidant status. Resting levels of IL‐6 and TNF‐α and exercise‐induced peak variations of TBARS, IL‐6 and TNF‐α were negatively correlated with the baseline PaO2. In COPD patients, the peak increases in IL‐6 and TBARS were attenuated when exercise hyperventilation reduced the baseline hypoxemia. Our study indicates that the PaO2 level affects both the exercise‐induced oxidative stress and cytokine response in hypoxemic COPD patients.
Molecular and diffusion tensor imaging of epileptic networks
Authors: Luat Aimee F. , Chugani Harry T. 
Published: February 2008

Summary Several studies have shown that seizure‐induced cellular and molecular changes associated with chronic epilepsy can lead to functional and structural alterations in the brain. Chronic epilepsy, when medically refractory, may be associated with an expansion of the epileptic circuitry to involve complex interactions between cortical and subcortical neuroanatomical substrates. Progress in neuroimaging has led not only to successful identification of epileptic foci for surgical resection, but also to an improved understanding of the functional and microstructural changes in long‐standing epilepsy. Positron emission tomography (PET), functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) are all promising tools that can assist in elucidating the underlying pathophysiology in chronic epilepsy. Studies using PET scanning have demonstrated dynamic changes associated with the evolution from acute to chronic intractable epilepsy. Among these changes are data to support the existence of secondary epileptogenesis in humans. MRI with DTI is a powerful tool which has the ability to characterize microstructural abnormalities in epileptic foci, and to demonstrate the white matter fibers and tracts participating in the epileptic network. In this review, we illustrate how PET and DTI can be applied to depict the functional and microstructural alterations associated with chronic epilepsy.
Epileptic networks studied with EEG‐fMRI
Authors: Gotman Jean 
Published: February 2008

Summary It is not easy to determine the location of the cerebral generators and the other brain regions that may be involved at the time of an epileptic spike seen in the scalp EEG. The possibility to combine EEG recording with functional MRI scanning (fMRI) opens the opportunity to uncover the regions of the brain showing changes in metabolism and blood flow in response to epileptic spikes seen in the EEG. These regions are presumably involved in the abnormal neuronal activity at the origin of epileptic discharges. This paper reviews the methodology involved in performing such studies, including the special techniques required for recording the EEG inside the scanner and the statistical issues in analyzing the fMRI signal. We then discuss the results obtained in patients with different types of focal epileptic disorders and in patients with primary generalized epilepsy. The results in general indicate that interictal epileptic discharges may affect brain areas well beyond the presumed region in which they are generated. The noninvasive nature of this method opens new horizons in the investigation of brain regions involved and affected by epileptic discharges.
States on Steroids: The Intergovernmental Odyssey of American Climate Policy
Authors: Rabe Barry G. 
Published: February 2008

AbstractClimate change has conventionally been framed as an issue that would be addressed by an international regime established through negotiation among nation‐states. The experience of policy development in the decade following the signing of the Kyoto Protocol indicates that climate change also needs to be examined as a challenge of multilevel governance. The increasingly central role of state governments in American climate policy formation squares with recent experience in other Western democracies that share authority across governmental levels. This paper examines the American experience, considering factors that have contributed to a state‐centric policy process and using that body of experience to assess competing strategic choices faced by individual states based on their mix of emission trends and policy adoption rates. In turn, the collective state experience allows for consideration of the varied political feasibility of competing climate policy tools that remain under active review in subnational, national, and international contexts. The paper concludes with a set of scenarios that explore different ways in which a state‐centric system may be integrated with expanding involvement at the national level.
The Politics of “Entrepreneurial” Economic Development Policy of States in the U.S.
Authors: Hart David M. 
Published: February 2008

Abstract“Entrepreneurial” economic development strategies at the state level in the United States, which focus on nurturing home‐grown, high‐growth businesses, lack immediate payoffs for politically powerful constituencies, a condition that would seem likely to limit their appeal compared to the alternative “locational” strategy of attracting large investments from elsewhere. Nonetheless, many U.S. states have added programs with entrepreneurial attributes to their economic development portfolios in recent years. This paper explores how the political obstacles to such programs have been overcome. In a few cases, an institutional innovation in the policy‐making process drew in new participants who provided ideas for and support to programs with entrepreneurial attributes. More commonly, the preferences of executive branch officials, especially governors, appear to have been critical to the enactment and implementation of such programs. This finding suggests that economic development policy making may be more technocratic than is commonly believed.
Developing the Digital Content Industry in Taiwan
Authors: Tsai Hsin‐Hann , Lee Hong‐Yuh , Yu Hsiao‐Cheng 
Published: February 2008

AbstractThe average global annual growth rate of digital content products has grown exponentially. This is because of the technology advancement, cost reduction, and availability of the enabling technologies, e.g., digital processing, digital storage, and digital telecommunications. The development of the digital content industry (DCI) requires a strong cultural background, creative ideas, respect of intellectual property rights, and telecommunications infrastructure, which are all dependent on government supportive policies. This study summarizes the government policies, progress, and obstacles in the development of Taiwan's DCI and compares these subjects with other countries, including the United States, EU countries, Japan, and Korea. In this paper, Taiwan's DCI opportunities and challenges will be discussed, and strategies and recommendations will be provided, based on Taiwan's unique resources and competitive advantages.