bluuebunny/crossref_metadata_2025_split huggingface dataset:
Non-Terminating Basic Hypergeometric Series and the q-Zeilberger Algorithm
Authors: Chen William Y. C. , Hou Qing-Hu , Mu Yan-Ping 
Published: October 2008

AbstractWe present a systematic method for proving non-terminating basic hypergeometric identities. Assume that k is the summation index. By setting a parameter x to xqn, we may find a recurrence relation of the summation by using the q-Zeilberger algorithm. This method applies to almost all non-terminating basic hypergeometric summation formulae in the work of Gasper and Rahman. Furthermore, by comparing the recursions and the limit values, we may verify many classical transformation formulae, including the Sears–Carlitz transformation, transformations of the very well-poised 8φ7 series, the Rogers–Fine identity and the limiting case of Watson's formula that implies the Rogers–Ramanujan identities.
Hecke C*-Algebras, Schlichting Completions and Morita Equivalence
Authors: Kaliszewski S. , Landstad Magnus B. , Quigg John 
Published: October 2008

AbstractThe Hecke algebra of a Hecke pair (G, H) is studied using the Schlichting completion (Ḡ, ), which is a Hecke pair whose Hecke algebra is isomorphic to and which is topologized so that is a compact open subgroup of Ḡ. In particular, the representation theory and C*-completions of are addressed in terms of the projection using both Fell's and Rieffel's imprimitivity theorems and the identity . An extended analysis of the case where H is contained in a normal subgroup of G (and in particular the case where G is a semi-direct product) is carried out, and several specific examples are analysed using this approach.
Vulnerable relations: lifecourse, wellbeing and social exclusion in Buenos Aires, Argentina
Authors: LLOYD-SHERLOCK PETER , LOCKE CATHERINE 
Published: October 2008

ABSTRACTMany have presumed that in developing countries, contact with children is beneficial to older people's wellbeing, and particularly that women receive more support from children than men because of their lifelong commitment to family responsibilities. This study questions these stylised notions through an analysis of 22 life histories of older women and men living in a district with high rates of social exclusion in Buenos Aires, Argentina. It focuses on the subjective accounts of relationships with children and grandchildren and their influence on current wellbeing. The life histories reveal complex lived experiences and the significance of key events. The informants speak of the anxiety and harm caused by struggling children, about problems of remote relations with successful children, and of the insecurity of the neighbourhood. The analysis contrasts a materialistic interpretation of the influence of children on older people's wellbeing with the informants' more holistic evaluation of family relationships. By applying a life-course framework, we demonstrate that children may be a key source of vulnerability for older people, that the gendering of parent-child relations and later-life wellbeing is nuanced, that both local and national conditions influence relationships with specific children, with implications for the intergenerational transmission of wellbeing.
A cross-linguistic investigation of the acquisition of the pragmatics of indefinite and definite reference in two-year-olds
Authors: ROZENDAAL MARGOT ISABELLA , BAKER ANNE EDITH 
Published: October 2008

ABSTRACTThe acquisition of reference involves both morphosyntax and pragmatics. This study investigates whether Dutch, English and French two- to three-year-old children differentiate in their use of determiners between non-specific/specific reference, newness/givenness in discourse and mutual/no mutual knowledge between interlocutors. A brief analysis of the input shows a clear association between form and function, although there are some language differences in this respect. As soon as determiner use can be statistically analyzed, the children show a relatively adult-like pattern of association for the distinctions of non-specific/specific and newness/givenness. The distinction between mutual/no mutual knowledge appears later. Reference involving no mutual knowledge is scarcely evidenced in the input and barely used by the children at this age. The development of associations is clearly related to the rate of determiner development, the French being quickest, then the English, then the Dutch.
The relationship of parenting stress and child temperament to language development among economically disadvantaged preschoolers
Authors: NOEL MELANIE , PETERSON CAROLE , JESSO BEULAH 
Published: October 2008

ABSTRACTOral language skills in the preschool years are predictive of children's later reading success and literacy acquisition, and among these language skills, vocabulary and narrative ability play important roles. Children from low socioeconomic families face risks to their language development and because of threats to these skills it is important to identify factors that promote their development among high-risk groups. This preliminary study explored two potential factors that may be related to language skills in 56 low SES mother–child dyads (children aged 2 ; 8–4 ; 10), namely child temperament and parenting stress. Results showed that child temperament and parenting stress were related to children's oral language skills. Child temperament characteristics that would likely aid social interaction were related to narrative ability and children rated high on emotionality had poorer receptive vocabulary skills. Parenting stress was related to children's receptive and expressive vocabulary skills. Results are interpreted in terms of the possible mediating role of parent–child interactions in children's oral language skill development, and future directions for family intervention are discussed.
From emotion resonance to empathic understanding: A social developmental neuroscience account
Authors: Decety Jean , Meyer Meghan 
Published: October 2008

AbstractThe psychological construct of empathy refers to an intersubjective induction process by which positive and negative emotions are shared, without losing sight of whose feelings belong to whom. Empathy can lead to personal distress or to empathic concern (sympathy). The goal of this paper is to address the underlying cognitive processes and their neural underpinnings that constitute empathy within a developmental neuroscience perspective. In addition, we focus on how these processes go awry in developmental disorders marked by impairments in social cognition, such as autism spectrum disorder, and conduct disorder. We argue that empathy involves both bottom-up and top-down information processing, underpinned by specific and interacting neural systems. We discuss data from developmental psychology as well as cognitive neuroscience in support of such a model, and highlight the impact of neural dysfunctions on social cognitive developmental behavior. Altogether, bridging developmental science and cognitive neuroscience helps approach a more complete understanding of social cognition. Synthesizing these two domains also contributes to a better characterization of developmental psychopathologies that impacts the development of effective treatment strategies.
The changing impact of genes and environment on brain development during childhood and adolescence: Initial findings from a neuroimaging study of pediatric twins
Authors: Lenroot Rhoshel K. , Giedd Jay N. 
Published: October 2008

AbstractHuman brain development is created through continuing complex interactions of genetic and environmental influences. The challenge of linking specific genetic or environmental risk factors to typical or atypical behaviors has led to interest in using brain structural features as an intermediate phenotype. Twin studies in adults have found that many aspects of brain anatomy are highly heritable, demonstrating that genetic factors provide a significant contribution to variation in brain structures. Less is known about the relative impact of genes and environment while the brain is actively developing. We summarize results from the ongoing National Institute of Mental Health child and adolescent twin study that suggest that heritability of different brain areas changes over the course of development in a regionally specific fashion. Areas associated with more complex reasoning abilities become increasingly heritable with maturation. The potential mechanisms by which gene–environment interactions may affect heritability values during development is discussed.
The neural bases of obsessive–compulsive disorder in children and adults
Authors: Maia Tiago V. , Cooney Rebecca E. , Peterson Bradley S. 
Published: October 2008

AbstractFunctional imaging studies have reported with remarkable consistency hyperactivity in the orbitofrontal cortex (OFC), anterior cingulate cortex (ACC), and caudate nucleus of patients with obsessive–compulsive disorder (OCD). These findings have often been interpreted as evidence that abnormalities in cortico–basal ganglia–thalamo–cortical loops involving the OFC and ACC are causally related to OCD. This interpretation remains controversial, however, because such hyperactivity may represent either a cause or a consequence of the symptoms. This article analyzes the evidence for a causal role of these loops in producing OCD in children and adults. The article first reviews the strong evidence for anatomical abnormalities in these loops in patients with OCD. These findings are not sufficient to establish causality, however, because anatomical alterations may themselves be a consequence rather than a cause of the symptoms. The article then reviews three lines of evidence that, despite their own limitations, permit stronger causal inferences: the development of OCD following brain injury, pediatric autoimmune neuropsychiatric disorders associated with streptococcal infection, and neurosurgical lesions that attenuate OCD. Converging evidence from these various lines of research supports a causal role for the cortico–basal ganglia–thalamo–cortical loops that involve the OFC and ACC in the pathogenesis of OCD in children and adults.
B2[g] Sets and a Conjecture of Schinzel and Schmidt
Authors: CILLERUELO JAVIER , VINUESA CARLOS 
Published: October 2008

A set of integers is called a B2[g] set if every integer m has at most g representations of the form m = a + a′, with a ≤ a′ and a, a′ ∈ . We obtain a new lower bound for F(g, n), the largest cardinality of a B2[g] set in {1,. . .,n}. More precisely, we prove that infn→∞$\frac{F(g, n)}{\sqrt{gn}}\geq \frac 2{\sqrt \pi}-\e_g$ where ϵg → 0 when g → ∞. We show a connection between this problem and another one discussed by Schinzel and Schmidt, which can be considered its continuous version.
Influence of hyaluronan accumulation during cumulus expansion onin vitroporcine oocyte maturation
Authors: Yokoo Masaki , Kimura Naoko , Abe Hiroyuki , Sato Eimei 
Published: October 2008

SummaryDuring oocyte maturation, the cumulus–oocyte complexes (COCs) expand dramatically. This phenomenon, which is known as cumulus expansion, is the result of the synthesis and accumulation of hyaluronan in the extracellular space between cumulus cells. The purpose of this study was to investigate the effect of 6-diazo-5-oxo-l-norleucine (DON), an inhibitor of hyaluronan synthesis, on cumulus expansion duringin vitroporcine oocyte maturation and hyaluronan accumulation within COCs. Further, this study aimed to examine the influence of hyaluronan accumulation within COCs on the rate of oocyte maturation. Cumulus expansion was observed duringin vitromaturation. However, the addition of DON to the maturation medium significantly inhibited cumulus expansion. The total inhibition of hyaluronan accumulation within COCs was observed with the use of confocal microscopy. Moreover, a positive correlation between the area of cumulus expansion and the rate of oocyte maturation was observed. These results demonstrate that the hyaluronan accumulation within the COCs during oocyte maturation affects oocyte maturation. On the basis of these results, we propose that hyaluronan accumulation within the COCs during cumulus expansion is a necessary step in the porcine oocyte maturation process.
Questions de corps de définition pour les variétés abéliennes en caractéristique positive
Authors: Benoist Franck , Delon Françoise 
Published: October 2008

AbstractDichotomies in various conjectures from algebraic geometry are in fact occurrences of the dichotomy among Zariski structures. This is what Hrushovski showed and which enabled him to solve, positively, the geometric Mordell–Lang conjecture in positive characteristic. Are we able now to avoid this use of Zariski structures? Pillay and Ziegler have given a direct proof that works for semi-abelian varieties they called ‘very thin’, which include the ordinary abelian varieties. But it does not apply in all generality: we describe here an abelian variety which is not very thin. More generally, we consider from a model-theoretical point of view several questions about the fields of definition of semi-abelian varieties.
Circuits arithmétiques et calculs tensoriels
Authors: Malod Guillaume 
Published: October 2008

AbstractThe classes in Valiant's theory are classes of polynomials defined by arithmetic circuits. We characterize them by different notions of tensor calculus, in the vein of Damm, Holzer and McKenzie. This characterization underlines in particular the role played by properties of parallelization in these classes. We also give a first natural complete sequence for the class VPnb, the analogue of the class P in this context.
Impact of efflux transporters and of seizures on the pharmacokinetics of oxcarbazepine metabolite in the rat brain
Authors: Clinckers R , Smolders I , Michotte Y , Ebinger G , Danhof M , Voskuyl R A , Pasqua O Della 
Published: October 2008

Background and purpose:Accurate prediction of biophase pharmacokinetics (PK) is essential to optimize pharmacotherapy in epilepsy. Here, we characterized the PK of the active metabolite of oxcarbazepine, 10,11‐dihydro‐10‐hydroxy‐carbamazepine (MHD) in plasma and in the hippocampus. Simultaneously, the impact of acute seizures and efflux transport mechanisms on brain distribution was quantified.Experimental approach:Rats received subtherapeutic and anticonvulsant doses of MHD in non‐epileptic conditions and during focal pilocarpine‐induced limbic seizures. To evaluate the effect of efflux transport blockade, a separate group received subtherapeutic doses combined with intrahippocampal perfusion of verapamil. Free plasma and extracellular hippocampal MHD concentrations were determined using microdialysis and liquid chromatography techniques. An integrated PK model describing simultaneously the PK of MHD in plasma and brain was developed using nonlinear mixed effects modelling. A bootstrap procedure and a visual predictive check were performed to assess model performance.Key results:A compartmental model with combined zero‐ and first‐order absorption, including lag time and biophase distribution best described the PK of MHD. A distributional process appeared to underlie the increased brain MHD concentrations observed following seizure activity and efflux transport inhibition, as reflected by changes in the volume of distribution of the biophase compartment. In contrast, no changes were observed in plasma PK.Conclusions and implications:Simultaneous PK modelling of plasma and brain concentrations has not been used previously in the evaluation of antiepileptic drugs (AEDs). Characterisation of biophase PK is critical to assess the impact of efflux transport mechanisms and acute seizures on brain disposition and, consequently, on AED effects.British Journal of Pharmacology (2008) 155, 1127–1138; doi:10.1038/bjp.2008.366; published online 6 October 2008
Characterization of cytochrome bo3 activity in a native-like surface-tethered membrane
Authors: Weiss Sophie A. , Bushby Richard J. , Evans Stephen D. , Henderson Peter J. F. , Jeuken Lars J. C. 
Published: October 2008

We have developed a simple native-like surface-tethered membrane system to investigate the activity of cbo3 (cytochrome bo3), a terminal oxidase in Escherichia coli. The tethered membranes consist of E. coli inner-membrane extracts mixed with additional E. coli lipids containing various amounts of the cbo3 substrate UQ-10 (ubiquinol-10). Tethered membranes are formed by self-assembly from vesicles on to gold electrodes functionalized with cholesterol derivatives. cbo3 activity was monitored using CV (cyclic voltammetry) with electron transfer to cbo3 mediated by UQ-10. The apparent Km for oxygen with this system is 1.1±0.4 μM, in good agreement with values reported in the literature for whole-cell experiments and for purified cbo3. Increasing the concentration of lipophilic UQ-10 in the membrane leads to an increase in cbo3 activity. The activity of cbo3 with long-chain ubiquinones appears to be different from previous reports using short-chain substrate analogues such as UQ-1 in that typical Michaelis–Menten kinetics are not observed using UQ-10. This native-like membrane model thus provides new insights into the interaction of transmembrane enzymes with hydrophobic substrates which contrasts with studies using hydrophilic UQ analogues.
The cytoprotective actions of long-chain mono-unsaturated fatty acids in pancreatic β-cells
Authors: Morgan Noel G. , Dhayal Shalinee , Diakogiannaki Eleftheria , Welters Hannah J. 
Published: October 2008

Chronic exposure of pancreatic β-cells to long-chain fatty acids can cause loss of secretory function and enhanced apoptosis by a process of ‘lipotoxicity’, which may be a contributory factor to the rising incidence of Type 2 diabetes in humans. However, when incubated in vitro, β-cells respond differentially to long-chain saturated and mono-unsaturated fatty acids, suggesting that these molecules may regulate cell functionality by different mechanisms. In particular, it is clear that, whereas saturated fatty acids [e.g. palmitate (C16:0)] exert detrimental effects on β-cells, the equivalent mono-unsaturated species [e.g. palmitoleate (C16:1)] are well tolerated. Indeed, mono-unsaturated species are potently cytoprotective. The present review explores the differential effects of these various fatty acids on β-cell viability and considers the possible mechanisms involved in cytoprotection by mono-unsaturates.
NOX family NADPH oxidases in liver and in pancreatic islets: a role in the metabolic syndrome and diabetes?
Authors: Guichard Cécile , Moreau Richard , Pessayre Dominique , Epperson Terry Kay , Krause Karl-Heinz 
Published: October 2008

The incidence of obesity and non-esterified (‘free’) fatty acid-associated metabolic disorders such as the metabolic syndrome and diabetes is increasing dramatically in most countries. Although the pathogenesis of these metabolic disorders is complex, there is emerging evidence that ROS (reactive oxygen species) are critically involved in the aberrant signalling and tissue damage observed in this context. Indeed, it is now widely accepted that ROS not only play an important role in physiology, but also contribute to cell and tissue dysfunction. Inappropriate ROS generation may contribute to tissue dysfunction in two ways: (i) dysregulation of redox-sensitive signalling pathways, and (ii) oxidative damage to biological structures (DNA, proteins, lipids, etc.). An important source of ROS is the NOX family of NADPH oxidases. Several NOX isoforms are expressed in the liver and pancreatic β-cells. There is now evidence that inappropriate activation of NOX enzymes may damage the liver and pancreatic β-cells. In the context of the metabolic syndrome, the emerging epidemic of non-alcoholic steatohepatitis is thought to be NOX/ROS-dependent and of particular medical relevance. NOX/ROS-dependent β-cell damage is thought to be involved in glucolipotoxicity and thereby leads to progression from the metabolic syndrome to Type 2 diabetes. Thus understanding the role of NOX enzymes in liver and β-cell damage should lead to an increased understanding of pathomechanisms in the metabolic syndrome and diabetes and may identify useful targets for novel therapeutic strategies.
Molecular mechanisms of proteinuria in diabetes
Authors: Gnudi Luigi 
Published: October 2008

The epidemic of Type 2 diabetes, and the parallel rising incidence of end-stage renal disease, is progressively increasing worldwide. Kidney disease is one of the major chronic microvascular complications of diabetes, and both metabolic and haemodynamic perturbations participate in its development and progression towards end-stage renal disease. Hypertension and poor metabolic control seem to interact in causing the relentless decline in renal function seen in diabetic patients. Both high circulating glucose levels and increased glomerular capillary pressure act in conjunction in stimulating the different cellular pathways leading to kidney disease. It has been suggested that mechanical forces at the glomerular level may aggravate the metabolic insult by stimulating excessive cellular glucose uptake by up-regulating the facilitative GLUT-1 (glucose transporter-1). We propose the existence of a self-maintaining cellular mechanism whereby a haemodynamic stimulus on glomerular cells induces the up-regulation of GLUT-1, an event followed by greater glucose uptake and activation of intracellular metabolic pathways, resulting in excess TGF-β1 (transforming growth factor-β1) production. TGF-β1, one of the major prosclerotic cytokines in diabetic kidney disease, maintains the up-regulation of GLUT-1, perpetuating a series of cellular events that result, as their ultimate effect, in increased extracellular matrix synthesis and altered permeability of the glomerular filtration barrier. Mechanical and metabolic coupling could represent an important mechanism of injury in the diabetic kidney.
The long-chain fatty acid receptor, GPR40, and glucolipotoxicity: investigations using GPR40-knockout mice
Authors: Brownlie Ruth , Mayers Rachel M. , Pierce Jackie A. , Marley Anna E. , Smith David M. 
Published: October 2008

GPR40 (G-protein-coupled receptor 40) has been shown to be a physiologically relevant receptor for long-chain fatty acids. It is a family A G-protein-coupled receptor highly expressed in the β-cell where it increases insulin secretion by signalling via Gq and phospholipase C. Fatty acids are well known to mediate both acute stimulatory effects and chronic detrimental effects on the β-cell. GPR40-transgenic and GPR40−/− animals have been important tools in studies of the metabolic effects of GPR40. In the present article, we review the literature on transgenic GPR40 models and present some of our own studies on the effects of a high-fat diet on the metabolic phenotype of GPR40−/− mice. GPR40 ligands represent interesting novel therapies for Type 2 diabetes but it is presently unclear whether agonists or antagonists represent the best therapeutic approach.
55Mn-ENDOR of the S2-state multiline signal of Photosystem II from Thermosynechococcus elongatus
Authors: Pudollek Susanne , Lendzian Friedhelm , Bittl Robert 
Published: October 2008

Pulse EPR and 55Mn-ENDOR (electron nuclear double resonance) experiments at 34 GHz (Q-band) were performed on the S2 state of the OEC (oxygen-evolving complex) in PSII (Photosystem II) from Thermosynechococcus elongatus. The ENDOR spectra are discussed with respect to earlier data obtained from X- (9 GHz) and Q-band experiments on PSII preparations from spinach with and without the addition of methanol.