bluuebunny/crossref_metadata_2025 huggingface dataset:
Crossroads in GDNF therapy for Parkinson's disease
Authors: Sherer Todd B. , Fiske Brian K. , Svendsen Clive N. , Lang Anthony E. , Langston J. William
Published: February 2006

The development of a neuroprotective or neuroregenerative therapy for Parkinson's disease (PD) would be a major therapeutic advance. Unfortunately, results from a recent controlled clinical study delivering the neurotrophic factor, glial‐derived neurotrophic factor (GDNF), directly into brain did not demonstrate efficacy and safety of such a treatment. A critical review of available data suggests that there are questions that need to be answered before the future of GDNF as a therapy for PD can be determined. © 2006 Movement Disorder Society
Global existence and uniform decay for the coupled Klein–Gordon–Schrödinger equations with non‐linear boundary damping and memory term
Authors: Park Jong Yeoul , Kim Joung Ae
Published: February 2006

In this paper we are concerned with the existence and energy decay of solution to the initial boundary value problem for the coupled Klein–Gordon–Schrödinger equations with non‐linear boundary damping and memory term. Copyright © 2006 John Wiley & Sons, Ltd.
The dressed nonrelativistic electron in a magnetic field
Authors: Amour Laurent , Grébert Benoît , Guillot Jean‐Claude
Published: February 2006

We consider a nonrelativistic electron interacting with a classical magnetic field pointing along the x3‐axis and with a quantized electromagnetic field. When the interaction between the electron and photons is turned off, the electronic system is assumed to have a ground state of finite multiplicity. Because of the translation invariance along the x3‐axis, we consider the reduced Hamiltonian associated with the total momentum along the x3‐axis and, after introducing an ultraviolet cutoff and an infrared regularization, we prove that the reduced Hamiltonian has a ground state if the coupling constant and the total momentum along the x3‐axis are sufficiently small. We determine the absolutely continuous spectrum of the reduced Hamiltonian and, when the ground state is simple, we prove that the renormalized mass of the dressed electron is greater than or equal to its bare one. We then deduce that the anomalous magnetic moment of the dressed electron is nonnegative. Copyright © 2006 John Wiley & Sons, Ltd.
Existence and regularity of a weak solution to Maxwell's equations with a thermal effect
Authors: Yin Hong‐Ming
Published: February 2006

This paper deals with Maxwell's equations with a thermal effect, where the electric conductivity strongly depends on the temperature. It is shown that the coupled system has a global weak solution and the temperature is Hölder continuous if the conductivity decays suitably as temperature increases. Moreover, uniqueness of the solution is proved, which gives a positive answer for a open question from the previous research. The main idea for the global existence is based on deriving various energy estimates for the solution of the coupled system. Copyright © 2006 John Wiley & Sons, Ltd.
Global and exponential attractors for 3‐D wave equations with displacement dependent damping
Authors: Pata Vittorino , Zelik Sergey
Published: February 2006

A weakly damped wave equation in the three‐dimensional (3‐D) space with a damping coefficient depending on the displacement is studied. This equation is shown to generate a dissipative semigroup in the energy phase space, which possesses finite‐dimensional global and exponential attractors in a slightly weaker topology. Copyright © 2006 John Wiley & Sons, Ltd.
A heterogeneous‐network aided public‐key management scheme for mobile ad hoc networks
Authors: Tseng Yuh‐Min
Published: February 2006

A mobile ad hoc network does not require fixed infrastructure to construct connections among nodes. Due to the particular characteristics of mobile ad hoc networks, most existing secure protocols in wired networks do not meet the security requirements for mobile ad hoc networks. Most secure protocols in mobile ad hoc networks, such as secure routing, key agreement and secure group communication protocols, assume that all nodes must have pre‐shared a secret, or pre‐obtained public‐key certificates before joining the network. However, this assumption has a practical weakness for some emergency applications, because some nodes without pre‐obtained certificates will be unable to join the network. In this paper, a heterogeneous‐network aided public‐key management scheme for mobile ad hoc networks is proposed to remedy this weakness. Several heterogeneous networks (such as satellite, unmanned aerial vehicle, or cellular networks) provide wider service areas and ubiquitous connectivity. We adopt these wide‐covered heterogeneous networks to design a secure certificate distribution scheme that allows a mobile node without a pre‐obtained certificate to instantly get a certificate using the communication channel constructed by these wide‐covered heterogeneous networks. Therefore, this scheme enhances the security infrastructure of public key management for mobile ad hoc networks. Copyright © 2006 John Wiley & Sons, Ltd.
Acceleration schemes for computing centroidal Voronoi tessellations
Authors: Du Qiang , Emelianenko Maria
Published: February 2006

Centroidal Voronoi tessellations (CVT) have diverse applications in many areas of science and engineering. The development of efficient algorithms for their construction is a key to their success in practice. In this paper, we study some new algorithms for the numerical computation of the CVT, including the Lloyd–Newton iteration and the optimization based multilevel method. Both theoretical analysis and computational simulations are conducted. Rigorous convergence results are presented and significant speedup in computation is demonstrated through the comparison with traditional methods. Copyright © 2006 John Wiley & Sons, Ltd.
An energy‐based AMG coarsening strategy
Authors: Brannick J. , Brezina M. , MacLachlan S. , Manteuffel T. , McCormick S. , Ruge J.
Published: February 2006

Algebraic multigrid (AMG) is an iterative method that is often optimal for solving the matrix equations that arise in a wide variety of applications, including discretized partial differential equations. It automatically constructs a sequence of increasingly smaller matrix problems that hopefully enables efficient resolution of all scales present in the solution. The methodology is based on measuring how a so‐called algebraically smooth error value at one point depends on its value at another. Such a concept of strength of connection is well understood for operators whose principal part is an M‐matrix; however, the strength concept for more general matrices is not yet clearly understood, and this lack of knowledge limits the scope of AMG applicability. The purpose of this paper is to motivate a general definition of strength of connection, discuss its implementation, and present the results of initial numerical experiments. Copyright © 2006 John Wiley & Sons, Ltd.
Role of the ephrin and Eph receptor tyrosine kinase families in angiogenesis and development of the cardiovascular system
Authors: Zhang J , Hughes SE
Published: February 2006

Angiogenesis is a highly complex orchestrated process that plays a critical role in normal development and in the pathophysiology of multiple disease processes, including tumour neovascularization, ischaemic recovery, and wound healing. In recent years there has been a resurgence of interest in Eph receptors and their ligands, ephrins, as their participation in vasculogenesis and angiogenesis has become apparent. The Eph receptor family is the largest family of receptor tyrosine kinases identified to date. The Eph receptors and their membrane‐anchored ligands, ephrins, are unique in that they mediate bi‐directional signalling. This is concomitant with activation of the Eph receptor tyrosine kinase domain and transduction of the typical forward signal into the receptor‐bearing cell. The ligand‐receptor interaction also leads to transduction of a reverse signal into the ephrin‐bearing cell. The Eph/ephrin signalling mechanism is responsible for diverse and complex biological functions mediated by Eph receptors and ephrin ligands. These include vascular development, tissue‐border formation, cell migration, axon guidance, and synaptic plasticity. The role of Eph receptors and ephrins in the processes of development of the cardiovascular system, angiogenesis, and vascular remodelling has been the subject of intense investigation since they were first identified in 1987. This review addresses the role of this new growth factor receptor tyrosine kinase family in those processes and provides new insights into the way in which Eph receptors and ephrin ligands modulate the angiogenic response and participate in vascular remodelling and vascular boundary formation during development of the cardiovascular system and vascularization of cancer. Copyright © 2006 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Assessing teachers' perceptions for school‐based aggression prevention programs: Applying a cognitive‐ecological framework
Authors: Boxer Paul , Musher‐Eizenman Dara , Dubow Eric F. , Danner Stephanie , Heretick Donna M.L.
Published: February 2006

This article describes qualitative and quantitative assessment based on responses of 221 teachers from nine elementary schools in two districts (urban and suburban) to inform plans for reducing and preventing student aggression. Teachers' perceptions of students' aggressive behavior and beliefs were validated against students' self‐reports and archival disciplinary data. Using a brief survey, we found district‐ and grade‐level differences in teachers' perceptions of students' aggressive behavior and aggression supporting cognitions. Teacher reports on these two constructs each uniquely predicted teacher perceptions of the degree to which student aggression interferes with their jobs. Focus‐group interviews with teachers were used to elaborate on individual‐cognitive and ecological school factors related to student aggression, including procedures for handling aggression. The importance of teacher reports is highlighted, and implications for school program development are considered. © 2006 Wiley Periodicals, Inc. Psychol Schs 43: 331–344, 2006.
Relational aggression in children and adolescents: A review with implications for school settings
Authors: Merrell Kenneth W. , Buchanan Rohanna , Tran Oanh K.
Published: February 2006

This article provides an overview of the literature on relational aggression of school‐aged children and adolescents, with the specific aim of making this information relevant to school settings and education professionals. Relational aggression is discussed in terms of definitions, terms, and the importance of the school context. The literature on gender and familial influences as they relate to relational aggression is overviewed. Assessment methods for detecting relational aggression in children and adolescents are described, with an emphasis on measurement techniques most viable for capturing this sometimes‐elusive construct. We conclude with a discussion of proposed best practices in school settings for effectively preventing and responding to incidents of relational aggression within the context of social and emotional learning interventions and positive behavioral interventions and supports. © 2006 Wiley Periodicals, Inc. Psychol Schs 43: 345–360, 2006.
Fighting an epidemic: The role of schools in reducing childhood obesity
Authors: Pyle Sara A. , Sharkey Jill , Yetter Georgette , Felix Erika , Furlong Michael J. , Poston W.S. Carlos
Published: February 2006

Obesity among children and adolescents is a major public health concern affecting the physical and emotional health of youth while increasing their risk of reduced quality and duration of life. Schools and communities have begun to galvanize to address this epidemic and need quality empirical information to guide their policy, programming, and intervention efforts. This article reviews the definition of childhood obesity and the physical, psychosocial, and academic consequences of obesity among youth. The roles of schools and school psychologists in intervening against this overwhelming trend are discussed as well as current empirically based programs. Schools are recommended to take a comprehensive, multifaceted approach to school policies and programs to increase nutrition and physical activity. © 2006 Wiley Periodicals, Inc. Psychol Schs 43: 361–376, 2006.
Relational aggression: Understanding, identifying, and responding in schools
Authors: Young Ellie L. , Boye America E. , Nelson David A.
Published: February 2006

Relational aggression, harm through injury or manipulation of a relationship, has become fashionable, particularly in the popular press. Mental health professionals in schools can better serve students when they understand what is known about relational aggression, how it influences social behavior, and how it is related to children's well‐being. This article discusses the definition, identification, and consequences of relational aggression. Available intervention programs are introduced, and future directions for research, assessment, and intervention are addressed. © 2006 Wiley Periodicals, Inc. Psychol Schs 43: 297–312, 2006.
Structure and prevalence of PTSD symptomology in children who have experienced a severe tornado
Authors: Evans Linda Garner , Oehler‐Stinnett Judy
Published: February 2006

Children served by school psychologists are frequently impacted by natural disasters. In the United States, tornadoes are a particular threat but have been studied very little. The current investigation developed a scale for assessing posttraumatic stress disorder (PTSD) in children in Kindergarten to Grade 6 impacted by a severe tornado. Six factors were found: Avoidance, Re‐experiencing, Interpersonal Alienation, Interference with Daily Functioning, Physical Symptoms/Anxiety, and Foreshortened Future. Prevalence rates for PTSD symptomology ranged from 34 to 44% for factor scores and 41% for meeting all three Diagnostic and Statistical Manual of Mental Disorder, fourth edition‐text revision (DSM‐IV‐TR; American Psychiatric Association, 2000) criteria; 40% indicated no symptoms. Children's fear during the tornado and damage to their school were related to many factor scores. © 2006 Wiley Periodicals, Inc. Psychol Schs 43: 283–295, 2006.
Task performance and response to frustration in children with attention deficit hyperactivity disorder
Authors: Scime Melinda , Norvilitis Jill M.
Published: February 2006

The present study examined performance on an arithmetic task of increasing difficulty and a frustrating puzzle task for children with ADHD and comparison children. Emotional competence also was investigated in the two groups. Sixty‐four children, 21 previously diagnosed with ADHD, participated. Performance on the arithmetic task was measured in terms of completion and accuracy. Children with ADHD had similar rates of accuracy for all levels of difficulty, but completed fewer problems. Performance on the puzzle task was measured both through completion and persistence. Although children with ADHD persisted for a similar amount of time compared to children without ADHD, they were more likely to quit the task before completion. Children with ADHD also were more likely to report that they became frustrated with the task. Furthermore, they tended to report that in general, they become more frustrated than other children. With regard to emotional competence, children with ADHD did not differ from the comparison children on their reported understanding of their own emotions or attention to emotions; however, children with ADHD reported that they engage in less mood repair. © 2006 Wiley Periodicals, Inc. Psychol Schs 43: 377–386, 2006.
Building and sustaining communities that prevent mental disorders: Lessons from the field of special education
Authors: Reinke Wendy M. , Herman Keith C. , Tucker Carolyn M.
Published: February 2006

Quietly, at least beyond the awareness of many psychologists, a relatively new technology based on school‐wide behavior management strategies has emerged in special education to answer the call to build healthy communities. The success of these strategies in changing the practices of school systems and creating positive school climates may offer insights for school psychologists interested in preventing mental disorders and promoting health on a broader scale. Spreading the influence of school‐wide behavior supports to ensure that all schools provide the nurturing environment needed to promote academic and life success for all children is an important and immediate goal. Beyond the school, the challenge will be to implement and evaluate the impact of positive behavior supports in other connected communities. The present article reviews the history and present state of school‐wide behavior supports and prevention research, limitations of current practice, and opportunities for integrating school‐wide programs with psychological science and practice. © 2006 Wiley Periodicals, Inc. Psychol Schs 43: 313–329, 2006.
Synthesis and characterization of poly(ethylene oxide‐co‐ethylene carbonate) macromonomers and their use in the preparation of crosslinked polymer electrolytes
Authors: Elmér Anette Munch , Jannasch Patric
Published: February 2006

Methacrylate‐functionalized poly(ethylene oxide‐co‐ethylene carbonate) macromonomers were prepared in two steps by the anionic ring‐opening polymerization of ethylene carbonate at 180 °C, with potassium methoxide as the initiator, followed by the reaction of the terminal hydroxyl groups of the polymers with methacryloyl chloride. The molecular weight of the polymer went through a maximum after approximately 45 min of polymerization, and the content of ethylene carbonate units in the polymer decreased with the reaction time. A polymer having a number‐average molecular weight of 2650 g mol−1 and an ethylene carbonate content of 28 mol % was selected and used to prepare a macromonomer, which was subsequently polymerized by UV irradiation in the presence of different concentrations of lithium bis(trifluoromethanesulfonyl)imide salt. The resulting self‐supportive crosslinked polymer electrolyte membranes reached ionic conductivities of 6.3 × 10−6 S cm−1 at 20 °C. The coordination of the lithium ions by both the ether and carbonate oxygens in the polymer structure was indicated by Fourier transform infrared spectroscopy. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2195–2205, 2006
Using the reversible addition–fragmentation chain transfer process to synthesize core‐crosslinked micelles
Authors: Zhang Ling , Katapodi Kamani , Davis Thomas P. , Barner‐Kowollik Christopher , Stenzel Martina H.
Published: February 2006

Poly(2‐hydroxyethyl acrylate)–poly(n‐butyl acrylate) block copolymers were synthesized with the reversible addition–fragmentation chain transfer (RAFT) process. The block copolymers were synthesized successfully with either poly(2‐hydroxyethyl acrylate) or poly(n‐butyl acrylate) macro‐RAFT agents. The resulting block copolymers had narrow molecular weight distributions (polydispersity index = 1.3–1.4). Copolymer self‐aggregation in water yielded micelles, with the hydrodynamic diameter (Dh) values of the aggregates dependent on the length of both blocks according to Dh ∼ NBA1.17NHEA0.57, where NBA is the number of repeating units of n‐butyl acrylate and NHEA is the number of repeating units of 2‐hydroxyethyl acrylate. The micelles were subsequently stabilized via chain extension of the block copolymer with a crosslinking agent. The successful chain extension in a micellar system was confirmed by an increase in the molecular weight, which was detected with membrane osmometry. The crosslinked particles showed noticeably different aggregation behavior in diverse solvent systems. The uncrosslinked micelles formed by the block copolymer (NHEA = 260, NBA = 75) displayed a definite critical micelle concentration at 5.4 × 10−4 g L−1 in aqueous solutions. However, upon crosslinking, the critical micelle concentration transition became obscure. © 2006Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2177–2194, 2006
Novel conserved hydrolase domain in the CLCA family of alleged calcium‐activated chloride channels
Authors: Pawłowski Krzysztof , Lepistö Matti , Meinander Nina , Sivars Ulf , Varga Mikael , Wieslander Elisabet
Published: February 2006

Advanced protein structure prediction methods combined with structure modeling show that the mammalian proteins, described until now as calcium‐activated chloride channels (CLCAs), appear in fact to be membrane anchored metal‐dependent hydrolases, possibly proteases. A metallohydrolase structural domain was predicted, unexpectedly, in the CLCA sequences. The well‐conserved active site in the modeled structure of this hydrolase domain allows the prediction of catalytic action similar to that of metalloproteases. A number of protein structure prediction methods suggest the overall fold of the N‐terminal hydrolase domain to be most similar to that of zinc metalloproteases (zincins), notably matrixins. This is confirmed by analysis of the three‐dimensional structure model of the predicted CLCA1 hydrolase domain built using the known structure of the MMP‐11 catalytic domain. Fragments of CLCA1 corresponding to the modeled hydrolase domain were expressed in Escherichia coli, and the resulting proteins were readily refolded into monomeric soluble protein, indicating formation of stable independent domains. The homology model was used to predict putative substrate sequences. Homologs of mammalian CLCA genes were detected in the genomes of a vast array of multicellular animals: lower vertebrates, tunicates, insects, crustaceans, echinoderms, and flatworms. The hydrolase prediction is discussed in the context of published experimentally determined effects of CLCA proteins on chloride conductance. Altered proteolytic processing of full‐length CLCA1 containing a mutation abolishing the predicted hydrolase activity is shown as initial experimental evidence for a role of the hydrolase domain in processing of mature full‐length CLCA1. The hydrolase prediction together with the presented experimental data add to doubts about the function of CLCAs as chloride channels and strengthen the hypothesis of channel‐activating and/or channel‐accessory roles. Proteins 2006. © 2006 Wiley‐Liss, Inc.
Reconciling the “old” and “new” views of protein allostery: A molecular simulation study of chemotaxis Y protein (CheY)
Authors: Formaneck Mark S. , Ma Liang , Cui Qiang
Published: February 2006

A combination of thirty‐two 10‐ns‐scale molecular dynamics simulations were used to explore the coupling between conformational transition and phosphorylation in the bacteria chemotaxis Y protein (CheY), as a simple but representative example of protein allostery. Results from these simulations support an activation mechanism in which the β4–α4 loop, at least partially, gates the isomerization of Tyr106. The roles of phosphorylation and the conserved Thr87 are deemed indirect in that they stabilize the active configuration of the β4–α4 loop. The indirect role of the activation event (phosphorylation) and/or conserved residues in stabilizing, rather than causing, specific conformational transition is likely a feature in many signaling systems. The current analysis of CheY also helps to make clear that neither the “old” (induced fit) nor the “new” (population shift) views for protein allostery are complete, because they emphasize the kinetic (mechanistic) and thermodynamic aspects of allosteric transitions, respectively. In this regard, an issue that warrants further analysis concerns the interplay of concerted collective motion and sequential local structural changes in modulating cooperativity between distant sites in biomolecules. Proteins 2006. © 2006 Wiley‐Liss, Inc.
New phenomena of mixed breakdown in silicon
Authors: Lee C. I. , Ngo V. H. , Pan D. S.
Published: February 2006

A new theory is briefly presented to explain our recently observed anomalous phenomena in the mixed breakdown regime of two silicon diodes. The multiplication coefficients have larFge values at very small reverse biased voltage, first decrease with increasing bias and then drastically increase again. In the theory, both thermally generated carriers and different types of interband tunneling carriers are all included in initiating the impact ionization processes, each with a different dead space. The theory is expected to be a good approximation when the carrier distribution function is determined primarily by phonon scattering and impurity scattering. The anomalous trend in the newly observed multiplication coefficients can be well explained by the theory. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Size‐dependent elastic interaction between a screw dislocation and a circular nano‐hole with surface stress
Authors: Fang Q. H. , Liu Y. W.
Published: February 2006

The effect of surface stress on the size‐dependent interaction of a screw dislocation with a circular nano‐hole under remote antiplane shear loads is examined. By using the complex variable method, the analytical expressions of the complex potential in infinite matrix and the image force acting on the screw dislocation are obtained. The associated solutions to the problem of a screw dislocation interacting with a nano‐inhomogeneity are also given. The results show that the influence of the surface stress on the motion of the dislocation near the hole becomes remarkable when the size of the hole is reduced to nanometer scale, leading to that the normalized image force depends on the hole size which differs from the size‐independent classical elastic solution. Our results are helpful in the understanding of the motion mechanism of the dislocation and relevant physical phenomena in nano‐structured materials. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Trend, variability or extreme event? The importance of long‐term perspectives in river ecology
Authors: Reid Michael A. , Ogden Ralph W.
Published: February 2006

Temporal variability at extra‐annual scales is typically a feature of freshwater ecosystems, particularly in places like Australia where the climate is highly unpredictable and where recent anthropogenic changes have been dramatic. Accounting for this variability when studying freshwater systems is generally not possible if freshwater ecologists rely solely on measurements carried out in the course of studies that rarely exceed a few years in length. Alternative methods can be used to extend temporal perspective; however, we argue these are under‐utilised in river ecology. This paper outlines approaches for extending temporal perspective (historical studies, palaeolimnological studies and modelling) and illustrates, using pertinent examples, areas of river ecology where we believe they can be of particular use. We conclude with some suggestions for ways in which cooperation between relevant disciplines can be enhanced. Copyright © 2006 John Wiley & Sons, Ltd.
Flow variability in dryland rivers: boom, bust and the bits in between
Authors: Bunn Stuart E. , Thoms Martin C. , Hamilton Stephen K. , Capon Samantha J.
Published: February 2006

Australian dryland rivers are acknowledged as being among the most variable and unpredictable in the world in terms of their flow regimes. Although renowned for their spectacular floods over vast and complex floodplains, rivers exist for much of the time as discrete waterholes, which are important refugia for aquatic biota. Recent work has shown that waterholes are filled by surface flows and there is little evidence of groundwater contributions. The permanence of these refugia is largely determined by waterhole morphology and evaporative loss, and some waterholes can clearly persist for 2 years or more without surface flow connection. As a consequence, the spatial distribution of refugia for aquatic biota is determined not only by the physical template but also by the duration of dry spells and the timing of flow events. Flow variability also has a major influence on aquatic production in these systems and ultimately influences food availability for fish and other consumers. During dry spells, aquatic food webs in waterholes are largely supported by algal production in the shallow littoral zone. At the other extreme, during floods, the boom of aquatic production on floodplains provides an immense food resource. However, there are many occasions when in‐channel flows (flow pulses) result in periods where neither of these sources of production is likely to be available. Although such flow pulses are essential for the physical persistence and connectivity of waterholes, we propose that they may lead to food limitation and stress for populations of fish and other consumers. Water resource development in dryland rivers often leads to an increase in the frequency and duration of flow pulses, due to reduced floods and elevated base flows. This increase in the ‘bits in between’ natural boom or bust conditions may help to explain the observed decline in ecosystem health in dryland river systems with significant water resource development. Copyright © 2006 John Wiley & Sons, Ltd.
Variability in channel form in a free‐flowing dryland river
Authors: Beyer Patricia J.
Published: February 2006

This study examines channel form of the Verde River system in order to explain system fragmentation. Morphologic analyses draw from discharge and shear stress calculations generated by modelling the flow through 14 surveyed cross‐sections along the Verde River, representing six river segments with distinct hydrologic and geologic characteristics. At‐a‐station and downstream hydraulic geometries for the Verde River highlight local variability in channel morphology. Modified at‐a‐station hydraulic geometry analyses using cross‐section subsection discharge and shear stress values similarly show greater variability within cross‐sections than between cross‐sections. Competence and capacity increase at a fairly uniform rate for similar features throughout the system, indicating an overall efficiency in sediment transport. Variations in channel form and associated sediment transport as represented by competence and capacity are largely related to combinations of macroscale local factors, including channel pattern, gradient, valley width, tributary inputs and human activity rather than megascale, basin‐scale or subbasin scale factors. Copyright © 2006 John Wiley & Sons, Ltd.
World Survey on the Complications of Hepatic and Prostate Cryotherapy
Authors: Seifert Joachim K. , Morris David L.
Published: February 2006

n = 299) of whom we were aware. We requested information on the number of patients treated, the occurrence, and the clinical features of cryoshock and mortality and morbidity following cryotherapy of the prostate or liver. Altogether 134 completed questionnaires were returned (44.8%). Seventy‐two centers had experience with hepatic cryotherapy and 62 with prostate cryotherapy. Following hepatic cryotherapy, the phenomenon of cryoshock was observed in 21 of 2173 patients (1%) and was responsible for 6 of 33 perioperative deaths (18.2%). Cryoshock was rare following prostate cryotherapy (2 of 5432 patients, 0.04%) and did not contribute to the overall mortality of 0.06%. Hepatic and prostate cryotherapy are safe. Cryoshock is rare after prostate cryotherapy but occurs in 1% of patients following hepatic cryotherapy. Cryoshock is associated with a high risk of death, being responsible for 18.2% of deaths in this survey. Research regarding the mechanism and possible avoidance of cryoshock is required.
A Gamma-convergence argument for the blow-up of a non-local semilinear parabolic equation with Neumann boundary conditions
Authors: El Soufi A. , Jazar M. , Monneau R.
Published: February 2006

In this paper we study a simple non-local semilinear parabolic equation in a bounded domain with Neumann boundary conditions. We obtain a global existence result for initial data whose

L^{\infty }

-norm is less than a constant depending explicitly on the geometry of the domain. A natural energy is associated to the equation and we establish a relationship between the finite-time blow up of solutions and the negativity of their energy. The proof of this result is based on a Gamma-convergence technique.

Cet article est consacré à l'étude d'un modèle simple d'équation semi-linéaire parabolique non locale dans un domaine borné sous la condition de Neumann au bord. Nous obtenons un résultat d'existence globale pour les données initiales dont la norme infinie est majorée par une constante explicite qui dépend de la géométrie du domaine. En outre, nous associons une énergie naturelle à l'équation et établissons un lien entre l'explosion en temps fini des solutions et la négativité de leur énergie. La preuve de ce résultat est fondée sur une technique de Gamma-convergence.
Large time behavior for nonlinear higher order convection–diffusion equations
Authors: Qafsaoui Mahmoud
Published: February 2006

We study the large time asymptotic behavior, in

L^{p}

(

1 \leq p \leq \infty

), of higher derivatives

D^{\gamma }u(t)

of solutions of the nonlinear equation

\begin{cases}
&u_{t} + \mathcal{T}u = a \cdot \mathrm{∇}^{\theta }(\psi (u))\:&&\text{on }\:\mathbb{R}^{n} \times (0,\infty ), \\
&u(0) = u_{0}∊L^{1}(\mathbb{R}^{n}), &&
\end{cases}

where the integers

n

and

θ

are bigger than or equal to

1

,

a

is a constant vector in

\mathbb{R}^{p}

with

p = \tbinom{\theta + n−1}{ n−1}= \frac{(\theta + n−1)!}{\theta !(n−1)!}

. The function

ψ

is a nonlinearity such that

\psi \in\mathcal{C}^{\theta }(\mathbb{R})

and

\psi (0) = 0

, and

\mathcal{T}

is a higher order elliptic operator with nonsmooth bounded measurable coefficients on

\mathbb{R}^{n}

. We also establish faster decay when

u_{0}\in L^{1}(\mathbb{R}^{n}) \cap L^{\infty }(\mathbb{R}^{n})

.

Nous étudions le comportement asymptotique, dans

L^{p}

(

1 \leq p \leq \infty

), des dérivées d'ordre supérieur

D^{\gamma }u(t)

des solutions de l'équation nonlinéaire (1), où

n\in \mathbb{N}^{ \ast }

,

\theta \in \mathbb{N}^{ \ast }

et

a

est un vecteur constant de

\mathbb{R}^{p}

avec

p = \tbinom{\theta + n−1}{ n−1}

. La fonction

ψ

est nonlinéaire vérifiant

\psi \in \mathcal{C}^{\theta }(\mathbb{R})

et

\psi (0) = 0

, et

\mathcal{T}

est un opérateur elliptique d'ordre supérieur à coefficients peu réguliers dans

\mathbb{R}^{n}

. Nous étudions également le cas particulier où

u_{0}∊L^{1}(\mathbb{R}^{n}) \cap L^{\infty }(\mathbb{R}^{n})

.
\( L^{1} \) existence and uniqueness results for quasi-linear elliptic equations with nonlinear boundary conditions
Authors: Andreu F. , Igbida N. , Mazón J.M. , Toledo J.
Published: February 2006

In this paper we study the questions of existence and uniqueness of weak and entropy solutions for equations of type

−\mathrm{div}\mathbf{a}(x,Du) + \gamma (u) \ni \phi

, posed in an open bounded subset

Ω

of

\mathbb{R}^{N}

, with nonlinear boundary conditions of the form

\mathbf{a}(x,Du) \cdot \eta + \beta (u) \ni \psi

. The nonlinear elliptic operator

\mathrm{div}\mathbf{a}(x,Du)

is modeled on the

p

-Laplacian operator

\mathrm{\Delta }_{p}(u) = \mathrm{div}(|Du|^{p−2}Du)

, with

p > 1

,

γ

and

β

are maximal monotone graphs in

\mathbb{R}^{2}

such that

0 \in \gamma (0)

and

0 \in \beta (0)

, and the data

\phi \in L^{1}(\Omega )

and

\psi \in L^{1}(\partial \Omega )

.

Dans ce papier nous étudions les questions d'existence et d'unicité de solution faibles et entropiques pour des équations elliptiques de la forme

−\mathrm{div}\mathbf{a}(x,Du) + \gamma (u) \ni \phi

, dans un domaine borné

\Omega \subset \mathbb{R}^{N}

, avec des conditions au bord générales de la forme

\mathbf{a}(x,Du) \cdot \eta + \beta (u) \ni \psi

. L'opérateur

\mathrm{div}\mathbf{a}(x,Du)

généralise l'opérateur

p

-Laplacien

\mathrm{\Delta }_{p}(u) = \mathrm{div}(|Du|^{p−2}Du)

, avec

p > 1

,

γ

et

β

sont des graphes maximaux monotones dans

\mathbb{R}^{2}

tels que

0 \in \gamma (0) \cap \beta (0)

, et les données

ϕ

et

ψ

sont des fonctions

L^{1}

.
The effect of aortic valve replacement on plasma B‐type natriuretic peptide in patients with severe aortic stenosis — one year follow‐up
Authors: Neverdal Nils O. , Knudsen Cathrine Wold , Husebye Trygve , Vengen Øystein A. , Pepper John , Lie Mons , Tønnessen Theis
Published: February 2006

Background:

B‐type natriuretic peptide (BNP) is synthesized in cardiac tissue in response to increased wall stress and myocardial hypertrophy.

Aims:

In patients with severe aortic stenosis (AS) we examined the effect of aortic valve replacement (AVR) on plasma BNP and association between BNP and left ventricular mass index (LVMI) preoperatively and in the reverse‐remodeling phase twelve months postoperatively. We also examined the correlation between BNP and NYHA‐class and between BNP and age.

Methods and Results:

Plasma BNP analyses and echocardiographic measurements were performed preoperatively, before discharge after AVR, and at twelve months in twenty‐two patients. BNP was additionally measured at six months. Preoperatively, BNP was 283±45 pg/ml (mean±SEM). Following an immediate postoperative increase (441±38 pg/ml), BNP values decreased towards normal values at six and twelve months (139±25 and 130±18 pg/ml, respectively). LVMI was 206.5±15.8 g/m2 preoperatively and decreased to 119.7±7.2 g/m2 at twelve months with a correlation between LVMI and BNP preoperatively only (r=0.45, p<0.05). There was no correlation between BNP and NYHA‐class, whereas BNP correlated to age both pre‐ and post‐operatively.

Conclusion:

We report an increase in plasma BNP in patients with AS. Following a further transient increase postoperatively, BNP levels decreased at six and twelve months after AVR. BNP correlated with LVMI preoperatively, and with age both preoperatively and at twelve months.
The effects of static muscular contraction on blood pressure, heart rate, pain ratings and pressure pain thresholds in healthy individuals and patients with fibromyalgia
Authors: Kadetoff Diana , Kosek Eva
Published: February 2006

Aberrations of cardiovascular regulation and dysfunction of endogenous pain modulation have been reported in fibromyalgia (FM) patients. This study aimed at investigating the interactions between cardiovascular regulation and pain perception during static muscle contractions. Seventeen FM patients and 17 healthy controls performed a standardised static contraction (m. quadriceps femoris dx) until exhaustion. Blood pressure (BP), heart rate (HR), ratings of exertion/fatigue and pain intensity as well as pressure pain thresholds (PPTs) (at m. quadriceps dx and m. deltoideus dx) were assessed before, during and 15 min following contraction. Systolic and diastolic BP increased during contraction (p < 0.001) and decreased following contraction (p < 0.001) in both groups alike. A significant increase in HR was seen during contraction in FM patients (p < 0.001), but not in healthy controls (difference between groups p < 0.02). The rated exertion/fatigue and pain intensity increased more during contraction and remained elevated longer following contraction in the patient group. PPTs were lower in patients compared to controls at both sites at all times (p < 0.001). No group differences in PPT changes over time were found. In conclusion, no indication of an attenuated cardiovascular response to exercise was found in our FM patients. The more pronounced HR increase in patients during contraction was most likely due to deconditioning. No exercise related change in PPTs was seen in either group, most likely due to insufficient exercise intensity, but the contraction induced pain was more pronounced in the FM patients.
p8 Upregulation sensitizes astrocytes to oxidative stress
Authors: Carracedo Arkaitz , Egia Ainara , Guzmán Manuel , Velasco Guillermo
Published: February 2006

Here we studied the mechanism of cell sensitization to oxidative stress by analyzing the gene expression profile of serum‐deprived astrocytes. Exposure to serum‐free medium (i) sensitized astrocytes to oxidative stress, (ii) reduced the expression of several genes involved in protection against oxidative stress, including heme oxygenase 1, and (iii) changed the expression of several genes involved in the control of cell survival, including the stress‐regulated protein p8. Our results support that serum deprivation sensitizes astrocytes to oxidative stress via a p38 mitogen‐activated protein kinase‐dependent p8 upregulation that leads in turn to decreased heme oxygenase 1 expression.
Cloning and expression analysis of androgen receptor gene in chicken embryogenesis
Authors: Katoh Hironori , Ogino Yukiko , Yamada Gen
Published: February 2006

We cloned a full‐length androgen receptor (AR) cDNA from chicken (Gallus gallus) gonads. The cDNA sequence has an open reading frame of 2109 bp encoding 703 amino acids. The chicken AR (cAR) shares high homology with ARs from other species in its amino acid sequences, in particular DNA binding domain (DBD) and ligand binding domain (LBD). RT‐PCR analysis revealed that cAR mRNA is expressed in several embryonic tissues of both sexes, and relatively higher expression was observed in left ovary compared with testis. The immunoreactive signal of AR was co‐localized within the ovarian cell nucleus, while such nuclear localization was not detected in those of testis. To get insight on the possible role of androgen–AR signaling during gonadal development, non‐steroidal AR antagonist, flutamide, was administrated in ovo. The treatment induced the disorganization of sex cords in ovarian cortex at day 12 of incubation. The effect was restored by testosterone co‐treatment, implying the possibility that AR mediated signaling may be involved in ovarian morphogenesis. Furthermore, co‐treatment of flutamide with estradiol‐17β (E2) also restored the phenotype, suggesting androgen–AR signaling might activate aromatase expression that is necessary for estrogen synthesis. These findings suggest androgen–AR signaling might contribute to chicken embryonic ovarian development.
Technical training, sponsored mobility, and functional differentiation: Elite formation in China in the reform era
Authors: Zang Xiaowei
Published: February 2006

Elite formation in state socialism is a key issue in both comparative mobility research and political sociology. Several perspectives have been proposed to explain the relative role of political loyalty and education in political mobility: a dual career path model, a party-sponsored mobility hypothesis, and a technocracy thesis. I propose an alternative approach, emphasizing the role of functional differentiation and its effect on elite recruitment in China. Using a data set on top Chinese leaders (n = 1588), I find that effects of political loyalty and technical training on elite recruitment are patterned by institutional arrangements. Data analysis supports my explanation of elite selection in China.
Estimated N leaching losses for organic and conventional farming in Denmark
Authors: TRYDEMAN KNUDSEN MARIE , SILLEBAK KRISTENSEN IB , BERNTSEN JØRGEN , MOLT PETERSEN BJØRN , STEEN KRISTENSEN ERIK
Published: February 2006

The impact of organic, compared with conventional, farming practices on N leaching loss was studied for Danish mixed dairy and arable farms using an N balance approach based on representative data. On mixed dairy farms, a simple N balance method was used to estimate N surplus and N leaching loss. On arable farms, the simple N balance method was unreliable due to changes in the soil N pool. Consequently, the Farm ASSEssment Tool (FASSET) simulation model was used to estimate N surplus, N leaching loss and the changes in the soil N pool.

The study found a lower N leaching loss from organic than conventional mixed dairy farms, primarily due to lower N inputs. On organic arable farms, the soil N pool increased over time but the N leaching loss was comparable with conventional arable farms. The soil N pool was increased primarily by organic farming practices and incorporation of straw. The highest increase in the soil N pool was seen on soils with a low initial level of organic matter. The N leaching loss was dependent on soil type, the use of catch crops and the level of soil organic matter, whereas incorporation of straw had a minor effect. N leaching was highest on sandy soils with a high level of soil organic matter and no catch crops. The present results stress the importance of using representative data from organic and conventional farming practices in comparative studies of N leaching loss. Lack of representative data has been a major weakness of previous comparisons on N leaching losses on organic and conventional farms.
Genetic variation among Spanish pea landraces revealed by Inter Simple Sequence Repeat (ISSR) markers: its application to establish a core collection
Authors: LÁZARO A. , AGUINAGALDE I.
Published: February 2006

One hundred and twenty Spanish landraces of peas (Pisum sativum L.) collected in different micro-climatic areas, together with three commercial varieties and one breeding line, were subjected to molecular characterization using Inter Simple Sequence Repeat (ISSR) amplification. Landraces originated from 7 to 1427 m asl. Most accessions were collected in temperate areas with dry Mediterranean humidity regimes. ISSR markers detected high levels of variability between accessions and were useful for identification of individuals and clarification of genetic relationships between them. The 18 groups obtained with molecular data were not significantly related to 21 agro/climatic regions. Clustering based on climatic and ISSR characters differed because the data types present different aspects of genetic diversity. These results will be applied to establish a pea core collection at the Plant Genetic Resources Centre of the Spanish National Institute of Agriculture and Food Research and Technology (CRF-INIA).
Agronomic regeneration of soil fertility in tropical Asian smallholder uplands for sustainable food production
Authors: DE COSTA W. A. J. M. , SANGAKKARA U. R.
Published: February 2006

Smallholder cropping systems are a vital component in the agricultural sectors of tropical Asia, especially in the developing nations. These systems are important for producing food and providing a livelihood to a major proportion of the populations of Asia. While the rice systems, usually cultivated under puddled conditions are considered stable, the upland or highland units, which provide a range of food, fibre and feed commodities, are generally situated on marginal lands. Low soil fertility, erosion, sub-optimal crop management and subsistence farming conditions characterize these units. Hence, these units require improved but low cost strategies to reverse the trend of lower productivity, loss of sustainability and most importantly, the loss of livelihood for the farming populations. Among the many strategies available, the regeneration of soil fertility through agronomic measures would be a useful and easily adoptable method of enhancing productivity of tropical Asian upland smallholding farming units. The methods available include the revival of age-old traditions such as adding organic matter directly to soils, green manuring and mimicking forest ecosystems through agroforestry. Agronomic measures using plants to enrich the soil and regenerate its supporting capacity are presented in the present paper. Relevant examples are cited to highlight the potential of these methods for regenerating productivity of the upland smallholder farming units and more importantly the agro-based livelihood of a large majority of the populations of tropical Asia.