bluuebunny/crossref_metadata_2025 huggingface dataset:
A new hierarchical parallelization scheme: Generalized distributed data interface (GDDI), and an application to the fragment molecular orbital method (FMO)
Authors: Fedorov Dmitri G. , Olson Ryan M. , Kitaura Kazuo , Gordon Mark S. , Koseki Shiro
Published: March 2004

A two‐level hierarchical scheme, generalized distributed data interface (GDDI), implemented into GAMESS is presented. Parallelization is accomplished first at the upper level by assigning computational tasks to groups. Then each group does parallelization at the lower level, by dividing its task into smaller work loads. The types of computations that can be used with this scheme are limited to those for which nearly independent tasks and subtasks can be assigned. Typical examples implemented, tested, and analyzed in this work are numeric derivatives and the fragment molecular orbital method (FMO) that is used to compute large molecules quantum mechanically by dividing them into fragments. Numeric derivatives can be used for algorithms based on them, such as geometry optimizations, saddle‐point searches, frequency analyses, etc. This new hierarchical scheme is found to be a flexible tool easily utilizing network topology and delivering excellent performance even on slow networks. In one of the typical tests, on 16 nodes the scalability of GDDI is 1.7 times better than that of the standard parallelization scheme DDI and on 128 nodes GDDI is 93 times faster than DDI (on a multihub Fast Ethernet network). FMO delivered scalability of 80–90% on 128 nodes, depending on the molecular system (water clusters and a protein). A numerical gradient calculation for a water cluster achieved a scalability of 70% on 128 nodes. It is expected that GDDI will become a preferred tool on massively parallel computers for appropriate computational tasks. © 2004 Wiley Periodicals, Inc. J Comput Chem 25: 872–880, 2004
Ligand–protein docking using a quantum stochastic tunneling optimization method
Authors: Mancera Ricardo L. , Källblad Per , Todorov Nikolay P.
Published: March 2004

A novel hybrid optimization method called quantum stochastic tunneling has been recently introduced. Here, we report its implementation within a new docking program called EasyDock and a validation with the CCDC/Astex data set of ligand–protein complexes using the PLP score to represent the ligand–protein potential energy surface and ScreenScore to score the ligand–protein binding energies. When taking the top energy‐ranked ligand binding mode pose, we were able to predict the correct crystallographic ligand binding mode in up to 75% of the cases. By using this novel optimization method run times for typical docking simulations are significantly shortened. © 2004 Wiley Periodicals, Inc. J Comput Chem 25: 858–864, 2004
Kinetics and mechanism of esterification of epoxy resin in presence of triphenylphosphine
Authors: Pal Neelam , Srivastava Akanksha , Rai J. S. P.
Published: March 2004

The kinetics of esterification of bisphenol‐A based epoxy resin with acrylic acid in presence of triphenylphosphine has been studied. The reaction exhibits a first‐order rate dependence with respect to [Epoxy] and [Catalyst]. A first‐order dependence of rate with respect to [Acid] has been observed during a particular kinetic run. However, a retarding effect of [Acid] on the rate has been observed by increasing the initial concentration of acid. A suitable mechanism consistent with the kinetic data is proposed and discussed. © 2004 Wiley Periodicals, Inc. Int J Chem Kinet 36: 280–285, 2004
Dynamic scaling for Eley‐Rideal reactions over rough surface
Authors: Chaudhari Ajay , Yan Ching‐Cher Sanders , Lee Shyi‐Long
Published: March 2004

Eley‐Rideal reaction mechanism is studied over rough surface of random deposition model. Two types of rough surface are considered: (1) different rough surface with same surface density and (2) different rough surface with different surface density. Dynamic scaling theory, which is generally applied to the growing surface, is applied for this reaction mechanism to obtain the temporal and spatial scaling parameters α and β. The scaling parameters are found to be negative in contrast to the positive scaling parameters in surface growth model. The values of β are the same for both types of surface whereas the values of α are different. © 2004 Wiley Periodicals, Inc. Int J Chem Kinet 36: 286–292, 2004
Pitting and crevice corrosion of superaustenitic stainless steels
Authors: Mori G. , Bauernfeind D.
Published: March 2004

Superaustenites are mainly used in offshore applications, oil production and chemical industry. Most important types of localised corrosion of these steels are pitting and crevice corrosion. Investigated materials were N08028, S31254 and three modified alloys. Chromium content of investigated alloys varied between 20 and 27%, molybdenum between 3.2 and 6.0%, nitrogen between 0.1 and 0.36% and copper between 0 and 1.1%. For means of comparison stainless steel AISI 316L has been included in the study.

Pitting and crevice corrosion of these highly corrosion resistant steels has been investigated by use of standardized tests. Critical pitting temperature and critical crevice temperatures were determined according to ASTM G 48, Methods C and D, respectively. Electrochemical measurements for determination of pitting potentials were done according to ASTM G 61 as well as for determination of critical pitting temperatures according to ASTM G 150.

Results are presented as function of MARC (Measure of alloying for resistance to corrosion) defined by Speidel since linear correlation coefficients were higher when compared to conventional PREN. Results obtained by different testing methods must not be compared directly. Every test however is sensitive to microstructural defects like precipitations and segregations that decrease corrosion resistance. The higher alloyed a material is, the higher is its tendency to form microstructural defects, and the more difficult is it to reach its theoretical corrosion resistance at given chemical composition.
Application limits of stainless steels in the petroleum industry
Authors: Oberndorfer M. , Thayer K. , Kästenbauer M.
Published: March 2004

Stainless steels have a great variety of potential applications in the petroleum industry, mainly as an alternative to carbon steel in corrosive environments. Within a number of media that can cause corrosion problems with these materials, only chloride solutions and hydrogen sulfide are of importance in oilfield service.

A reliable tool that permits the proper selection of stainless steels has yet been missing. In order to provide engineering diagrams for this purpose, pitting and stress corrosion cracking (SCC) tests were performed. Specimens were exposed to NaCl solutions containing from 3 to 100,000 ppm Cl− at temperatures from 40 to 200 °C. This test configuration was chosen to give a better representation of actual service conditions than accelerated standard test procedures do.

Tested materials were the austenitic stainless steel grades 321, 316Ti (API LC30‐1812) and 254 SMO, and 22Cr duplex (austenitic‐ferritic) steel (API LC65‐2205). Based on an optical examination of the specimens, no‐risk regions of chloride concentration vs. temperature have been identified. Subsequently, service temperature limits have been deduced for each tested material.

Thus, material failures by pitting and SCC can be prevented without overdesigning. The results of the testing series are applicable to all chloride environments without presence of H2S, as they have to be handled by primary production equipment, as well as transportation and gas processing facilities.
Microbially influenced corrosion of stainless steel by manganese oxidizing microorganisms
Authors: Linhardt P.
Published: March 2004

Based on the corrosion behaviour of stainless steels in fresh water and on the electrochemical properties of higher manganese oxides, the mechanism “Microbially influenced corrosion by manganese oxidizing microorganisms” (MIC by MOMOs) is presented as the consequence of biomineralized manganese oxides in contact with the metal. Localized corrosion may develop at elevated but normally undercritical chloride concentration in the water. The mechanism was found useful in the analysis of certain cases of unexpected failure of stainless steel in fresh water.
Influence of shot peening on the corrosion fatigue properties of a stainless steel for surgical implants
Authors: Wieser H.
Published: March 2004

For some applications in surgical implants a rough surface is desired, since the jagged surface structure assists the adhesion of bone material or surface coatings. Some implants are peened with coarse and sharp edged peening media. In order to avoid a distinct loss of fatigue strength, spherical peening balls should be used. The present paper shows for stainless steel X2CrNiMo18‐15‐3 that the effect of surface roughening can be compensated by the effect of compressive residual stresses in the surface layer.

However, the effect of surface flaws must not be ignored. For this reason, the shape and depth of surface flaws in shot peened surfaces has been examined and a classification of different types of surface flaws is presented.

Fatigue tests in laboratory air and in physiological NaCl solution showed that there is a distinct influence of the depth and shape of surface flaws on the fatigue strength. The use of coarser peening balls and a subsequent electrolytic polishing treatment leads to an increase of fatigue strength.

Furthermore, it is shown that shot peening may have a positive or negative effect on corrosion fatigue strength.
Versagensverhalten keramischer Faserverbundwerkstoffe mit poröser Matrix – experimentelle Untersuchungen und Modellierung
Authors: Tushtev K. , Horvath J. , Koch D. , Grathwohl G.
Published: March 2004

Bidirektional verstärkte Carbon/Carbon‐Verbundwerkstoffe besitzen eine poröse Matrix, die unter Beanspruchung das Versagensverhalten entscheidend mitbestimmt. Zur Klärung der Schädigungsmechanismen werden Zugversuche durchgeführt, bei denen die Proben in Richtung 0° und 45° zur Faserorientierung beansprucht werden. Die experimentellen Ergebnisse werden in einem makroskopischen Modell unter Berücksichtigung des nichtlinearen Spannungs‐Dehnungs‐Verhaltens der Komposite erfasst. Das Modell basiert auf den Konzepten der Schädigungs‐ und Plastizitätstheorie und ist auf das mechanische Werkstoffverhalten unter quasistatischer Belastung begrenzt. Das vorgeschlagene Modell wird mit Hilfe zusätzlicher Zugexperimente, bei denen die Fasern in verschiedenen Belastungsrichtungen orientiert sind, verifiziert.
Micromechanical Modelling of Shape Memory Alloy Composites
Authors: Wang YF , Wang XM , Yue ZF
Published: March 2004

An isothermal finite element method (FEM) model has been applied to study the behavior of two kinds of shape memory alloy (SMA) composites. For SMA‐fiber reinforced normal metal composites, the FEM analysis shows that the mechanical behavior of the composites depends on the SMA volume fraction. For normal metal‐fiber reinforced SMA matrix composites, the SMA phase transformation is affected by the increasing Young’s modulus of the metal fiber. The phase transformation was also treated using a simple numerical analysis, which assumes that there are uniform stresses and strains distributions in the fiber and the matrix respectively. It is found that there is an obvious difference between the FEM analysis and the simple numerical assessment. Only FEM can provide reasonable predictions of phase transformations in SMA/normal metal composites.
Large‐scale identification and characterization of genes with asymmetric expression patterns in the developing chick retina
Authors: Shintani Takafumi , Kato Akira , Yuasa‐Kawada Junichi , Sakuta Hiraki , Takahashi Masakazu , Suzuki Ryoko , Ohkawara Takeshi , Takahashi Hiroo , Noda Masaharu
Published: March 2004

To understand the molecular basis of topographic retinotectal projection, an overall view of the asymmetrically expressed molecules in the developing retina is needed. We performed a large‐scale screening using restriction landmark cDNA scanning (RLCS) in the embryonic day 8 (E8) chick retina. RLCS is a cDNA display system, in which a large number of cDNA species are displayed as two‐dimensional spots with intensities reflecting their expression levels as mRNA. We searched for spots that gave different signal intensities between the nasal and temporal retinas or between the dorsal and ventral retinas, and detected about 200 spots that were preferential on one side in the retina. The asymmetric expression of each gene was verified by Northern blotting and in situ hybridization. By subsequent analyses using molecular cloning, DNA sequencing, and database searching, 33 asymmetric molecules along the nasotemporal (N‐T) axis and 20 along the dorsoventral (D‐V) axis were identified. These included transcription factors, secretory factors, transmembrane proteins, and intracellular proteins with various putative functions. Their expression profiles revealed by in situ hybridization are highly diverse and individual. Moreover, many of them begin to be expressed in the retina from the early developmental stages, suggesting that they are implicated in the establishment and maintenance of regional specificity in the developing retina. The molecular repertoire revealed by this work will provide candidates for future studies to elucidate the molecular mechanisms of topographic retinotectal map formation. © 2004 Wiley Periodicals, Inc. J Neurobiol 59: 34–47, 2004
Polarity and laminar formation of the optic tectum in relation to retinal projection
Authors: Nakamura Harukazu , Sugiyama Sayaka
Published: March 2004

The mes‐metencephalic boundary (isthmus) works as an organizer for the tectum, and the organizing molecule may be Fgf8. The region where Otx2, En1, and Pax2 are expressed overlappingly may differentiate into the mesencephalon. The di‐mesencephalic and mes‐metencephalic boundaries are determined by repressive interaction of Pax6 and En1/Pax2 and of Otx2 and Gbx2, respectively. The optic tectum is a visual center in lower vertebrates. The tectum and the retina should be regionalized and be positionally specialized for the proper retinotopic projection. Gradient of En2 plays a crucial role in rostrocaudal polarity formation of the tectum. En2 confers caudal characteristics of the retina by inducing ephrinA2 and A5, which are the repellant molecules for the growth cones of temporal retinal ganglion cells. Grg4 antagonizes the isthmus‐related genes, and is involved in the formation of di‐mesencephalic boundary and tectal polarity formation at an early phase of development. Then, Grg4 plays a role in tectal laminar formation by controlling the migration pathway. Migration pathway of tectal postmitotic cells changes after E5. The late migratory cells split the early migratory neurons to form laminae h–j of SGFS. Grg4 is expressed in the ventricular layer after E5, and forces postmitotic cells to follow the late migratory pathway, though retinal fibers terminate at laminae a–f of SGFS. Misexpression of Grg4 disrupts the lamina g, and in such tecta retinal arbors invade deep into the tectal layer, indicating that lamina g is a nonpermissive lamina for the retinal arbors. © 2004 Wiley Periodicals, Inc. J Neurobiol 59: 48–56, 2004
EphrinB2a in the zebrafish retinotectal system
Authors: Wagle Mahendra , Grunewald Barbara , Subburaju Sivan , Barzaghi Cristiana , Le Guyader Sylvie , Chan Joanne , Jesuthasan Suresh
Published: March 2004

Members of the Eph‐B family of receptors tyrosine kinase and their transmembrane ligands have been implicated in dorsoventral patterning of the vertebrate retinotectal projection. In the zebrafish retinotectal system, however, ephrinB2a is expressed strongly in the posterior tectum, in tectal neurons that form physical contacts with retinal ganglion cell (RGC) axons. In the gnarled mutant, where tectal neurons form ectopically in the pretectum, RGC axons stall before entering the tectum, or else are misrouted or branch aberrantly in the tectal neuropil. Ectopic expression of ephrinB2a in the anterior midbrain of wild‐type embryos, with the aid of baculovirus, also inhibits RGC axon entry into the tectum. In vitro, zebrafish RGC axons are repelled by stripes of purified ephrinB2a. It is proposed that ephrinB2a may signal a subpopulation of RGC axons that they have reached their target neurons in the tectum. © 2004 Wiley Periodicals, Inc. J Neurobiol 59: 57–65, 2004
Computational modeling of retinotopic map development to define contributions of EphA‐ephrinA gradients, axon‐axon interactions, and patterned activity
Authors: Yates Paul A. , Holub Alex D. , McLaughlin Todd , Sejnowski Terrence J. , O'Leary Dennis D.M.
Published: March 2004

The topographic projection of retinal ganglion cell (RGC) axons to mouse superior colliculus (SC) or chick optic tectum (OT) is formed in three phases: RGC axons overshoot their termination zone (TZ); they exhibit interstitial branching along the axon that is topographically biased for the correct location of their future TZ; and branches arborize preferentially at the TZ and the initial exuberant projection refines through axon and branch elimination to generate a precise retinotopic map. We present a computational model of map development that demonstrates that the countergradients of EphAs and ephrinAs in retina and the OT/SC and bidirectional repellent signaling between RGC axons and OT/SC cells are sufficient to direct an initial topographic bias in RGC axon branching. Our model also suggests that a proposed repellent action of EphAs/ephrinAs present on RGC branches and arbors added to that of EphAs/ephrinAs expressed by OT/SC cells is required to progressively restrict branching and arborization to topographically correct locations and eliminate axon overshoot. Simulations show that this molecular framework alone can develop considerable topographic order and refinement, including axon elimination, a feature not programmed into the model. Generating a refined map with a condensed TZ as in vivo requires an additional parameter that enhances branch formation along an RGC axon near sites that it has a higher branch density, and resembles an assumed role for patterned neural activity. The same computational model generates the phenotypes reported in ephrinA deficient mice and Isl2‐EphA3 knockin mice. This modeling suggests that gradients of counter‐repellents can establish a substantial degree of topographic order in the OT/SC, and that repellents present on RGC axon branches and arbors make a substantial contribution to map refinement. However, competitive interactions between RGC axons that enhance the probability of continued local branching are required to generate precise retinotopy. © 2004 Wiley Periodicals, Inc. J Neurobiol 59: 95–113, 2004
Convergent and divergent signaling mechanisms of growth cone collapse by ephrinA5 and slit2
Authors: Wong Eric V. , Kerner Julie A. , Jay Daniel G.
Published: March 2004

EphrinA5 and slit2 are important repulsive guidance cues in the developing retinotectal system. Both ephrinA5 and slit2 cause growth cone collapse of embryonic chick retinal ganglion growth cones cultured on EHS laminin. However, the signaling mechanism that these guidance cues initiate to cause collapse remains unclear. Here we provide evidence that while both ephrinA5 and slit2 cause collapse in morphologically similar ways, the intracellular signaling leading to the collapse involves shared as well as divergent paths. Pharmacological inhibition of either phosphatidylinositol 3‐kinase (PI3K) or src family kinases prevented both ephrinA5‐mediated and slit2‐mediated growth cone collapse. In contrast, the inhibition of nonclassical protein kinase C (PKC) isoforms blocked ephrinA5‐mediated collapse, but did not interfere with slit2‐mediated collapse. PI3K was copurified by affinity chromatography with either the ephrinA5 receptors (ephAs) or the slit2 receptor (roundabout). Colocalization studies have also shown that src family kinase members are recruited to the ephA and roundabout receptors upon activation. In contrast, PKC members are recruited to the ephA receptors, but not to the roundabout receptors, upon activation. This demonstrates distinct points of convergence and divergence between the two signaling molecules, ephrinA5 and slit2, and their repulsive guidance in the chick retinotectal system. © 2004 Wiley Periodicals, Inc. J Neurobiol 59: 66–81, 2004
Activity‐driven sharpening of the retinotectal projection: The search for retrograde synaptic signaling pathways
Authors: Schmidt John T.
Published: March 2004

Patterned visual activity, acting via NMDA receptors, refines developing retinotectal maps by shaping individual retinal arbors. Because NMDA receptors are postsynaptic but the retinal arbors are presynaptic, there must be retrograde signals generated downstream of Ca++ entry through NMDA receptors that direct the presynaptic retinal terminals to stabilize and grow or to withdraw. This review defines criteria for retrograde synaptic messengers, and then applies them to the leading candidates: nitric oxide (NO), brain‐derived neurotrophic factor (BDNF), and arachidonic acid (AA). NO is not likely to be a general mechanism, as it operates only in selected projections of warm blooded vertebrates to speed up synaptic refinement, but is not essential. BDNF is a neurotrophin with strong growth promoting properties and complex interactions with activity both in its release and receptor signaling, but may modulate rather than mediate the retrograde signaling. AA promotes growth and stabilization of synaptic terminals by tapping into a pre‐existing axonal growth‐promoting pathway that is utilized by L1, NCAM, N‐cadherin, and FGF and acts via PKC, GAP43, and F‐actin stabilization, and it shares some overlap with BDNF pathways. The actions of both are consistent with recent demonstrations that activity‐driven stabilization includes directed growth of new synaptic contacts. Certain nondiffusible factors (synapse‐specific CAMs, ephrins, neurexin/neuroligin, and matrix molecules) may also play a role in activity‐driven synapse stabilization. Interactions between these pathways are discussed. © 2004 Wiley Periodicals, Inc. J Neurobiol 59: 114–133, 2004
Growth and guidance cues for regenerating axons: Where have they gone?
Authors: Koeberle Paulo D. , Bähr Mathias
Published: March 2004

Both attractive and repellent cues are required to guide developing axons to their targets in the central nervous system. Critical guidance molecules in the developing brain include the semaphorins, netrins, slits, and ephrins. Current research indicates that many of these molecules and their receptors are expressed in the adult central nervous system (CNS), and that injury can alter the levels of these ligands/receptors. Recent studies have begun the process of elucidating the functions of these receptors in adult mammals, and the effects that they have on the regeneration of adult neurons. This review addresses our current knowledge with respect to the response of adult CNS neurons to axonal injury, interventions for enhancing the survival and regeneration of injured neurons, and the expression of developmental axon guidance cues in the injured mature CNS, with specific focus on the retino‐tectal projection. © 2004 Wiley Periodicals, Inc. J Neurobiol 59: 162–180, 2004
Of lasers, mutants, and see‐through brains: Functional neuroanatomy in zebrafish
Authors: Gahtan Ethan , Baier Herwig
Published: March 2004

Behavioral functions are carried out by localized circuits in the brain. Although this modular principle is clearly established, the boundaries of modules, and sometimes even their existence, are still debated. Zebrafish might offer distinct advantages in localizing behaviors to discrete brain regions because of the ability to visualize, record from, and lesion precisely identified populations of neurons in the brain. In addition, genetic screens in zebrafish enable the isolation of mutations that disrupt neural pathways and/or behaviors, as an alternative lesioning technique with complementary strengths to laser ablations. For example, the Mauthner cell, a large identified neuron in the hindbrain, has been postulated to be both necessary and sufficient for the execution of escapes. We discuss in this review how experiments, using laser ablations, calcium imaging, and mutants have eroded this notion. Even in a simple behavior, such as escape, many parallel pathways appear to be involved with no single one being absolutely necessary. Lesion studies and the analysis of behavioral mutants are now also beginning to elucidate the functional architecture of the zebrafish visual system. Although still in an embryonic stage, the neuroanatomy of behaviors in zebrafish has a bright future. © 2004 Wiley Periodicals, Inc. J Neurobiol 59: 147–161, 2004
The fully Sinc‐Galerkin method for time‐dependent boundary conditions
Authors: Koonprasert Sanoe , Bowers Kenneth L.
Published: March 2004

The fully Sinc‐Galerkin method is developed for a family of complex‐valued partial differential equations with time‐dependent boundary conditions. The Sinc‐Galerkin discrete system is formulated and represented by a Kronecker product form of those equations. The numerical solution is efficiently calculated and the method exhibits an exponential convergence rate. Several examples, some with a real‐valued solution and some with a complex‐valued solution, are used to demonstrate the performance of this method. © 2004 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2004
On the numerical approach of the enthalpy method for the Stefan problem
Authors: Omrani Khaled
Published: March 2004

In this article an error bound is derived for a piecewise linear finite element approximation of an enthalpy formulation of the Stefan problem; we have analyzed a semidiscrete Galerkin approximation and completely discrete scheme based on the backward Euler method and a linearized scheme is given and its convergence is also proved. A second‐order error estimates are derived for the Crank‐Nicolson Galerkin method. In the second part, a new class of finite difference schemes is proposed. Our approach is to introduce a new variable and transform the given equation into an equivalent system of equations. Then, we prove that the difference scheme is second order convergent. © 2004 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2004
Exercise echocardiography reflects cumulative anthracycline exposure during childhood
Authors: Smibert Elizabeth , Carlin John B. , Vidmar Suzanna , Wilkinson Lynette C. , Newton Melissa , Weintraub Robert G.
Published: March 2004

Background

Low and moderate dose anthracycline therapy used in current treatment protocols, may be associated with subclinical abnormalities of cardiac function and late presentation with congestive heart failure. Exercise echocardiography is a useful and non‐invasive means of uncovering latent cardiac dysfunction in other settings. The purpose of this study is to determine whether exercise echocardiography has the potential to detect subclinical abnormalities of cardiac function in children treated with anthracyclines.

Procedure

One hundred ten children previously treated with anthracycline, in remission and off treatment for >12 months were assessed, together with 31 control subjects. Each subject had a resting ECG and echocardiogram performed, and following exercise on a treadmill according to the Bruce protocol, a repeat echocardiogram was performed.

Results

Cumulative anthracycline dose was the only patient variable related to any of the outcome measures. Resting fractional shortening was normal in the majority of treated patients but was inversely related to cumulative anthracycline dose (rate of decline 1.2%/100 mg/m2). Following peak exercise, the inverse relationship between fractional shortening and anthracycline dose was more pronounced (rate 2.7%/100 mg/m2).

Conclusions

Higher anthracycline doses are associated with a greater difference in peak fractional shortening between treated subjects and controls. Exercise echocardiography is a simple, relatively inexpensive tool that may enhance the detection of latent cardiac dysfunction after anthracycline administration during childhood. © 2004 Wiley‐Liss, inc.
Addressing the shortage of school psychologists: Introduction
Authors: McIntosh David E.
Published: March 2004

This article provides an overview of the special issue of Psychology in the Schools that addresses the shortage of school psychologists. A historical perspective is provided that sets the stage for exploring the current and future issues related to the shortage. Projections regarding the specific number of openings, where the shortages may occur, and implications for the future practice of school psychology also are provided. The issues surrounding respecialization are explored. Specific articles in the special issue addressing the disproportionately low number of minorities, the shortage of academic school psychologists, and the need for increasing the Board Certified School Psychologists also are discussed. Generally, all of the authors focus on the continued need to provide quality mental health services to children within the school setting while addressing growing personnel shortages in the coming years. School psychology as a profession must act quickly if it is to continue to provide high‐quality mental health services within the school setting. © 2004 Wiley Periodicals, Inc. Psychol Schs 41: 411–413, 2004.
The status of school psychology: Implications of a major personnel shortage
Authors: Curtis Michael J. , Hunley Sawyer A. , Grier Elizabeth Chesno
Published: March 2004

The findings of earlier studies are reviewed and results of analyses of recent data are reported in presenting an overview of the current and possible future status of school psychology in the United States. Recognizing that legislation could have major, but as yet unclear, implications for the field, projections suggest that school psychology is likely to face a severe personnel shortage over the next 10 years. Projections also indicate that serious, although less severe, shortages are likely to continue through at least 2020. Shortages are predicted to vary markedly by geographical region of the country and type of school setting. Potential implications of the shortage are examined for the public schools. © 2004 Wiley Periodicals, Inc. Psychol Schs 41: 431–442, 2004.
Academic school psychologists: Addressing the shortage
Authors: Little Steven G. , Akin‐Little K. Angeleque
Published: March 2004

The following article attempts to address the current shortage in school psychology faculty. Although little empirical evidence exists, the authors conclude that such a shortage exists. Possible explanations for the shortage and barriers to overcoming it are discussed. Preliminary data from a survey, which attempted to identify programs with a consistent track record in preparing students who enter academia, are presented. The article concludes with an examination of suggestions for improving the current situation. These suggestions are culled from two directors of successful school psychology programs and the authors' own experiences as trainers. © 2004 Wiley Periodicals, Inc. Psychol Schs 41: 451–459, 2004.
An APA‐informed perspective on the shortage of school psychologists: Welcome licensed psychologists into the schools (and did we mention xeriscape gardening together?)
Authors: Tharinger Deborah J. , Palomares Ronald S.
Published: March 2004

The authors were asked to respond to the shortage of school psychologists from the perspective of the Division of School Psychology of the American Psychological Association and the American Psychological Association (APA), and also chose to address the larger issue of the shortage and lack of accessibility of mental health services for children in the schools. We have recommended that licensed psychologists who want to provide psychological services in the schools have two options: (a) obtain the school psychology credential required by their state and work under the title of School Psychologist, and/or (b) obtain school practice competence and seek and create opportunities to practice psychology in the schools under their license as licensed psychologists. The joint document being developed in collaboration between the Division of School Psychology of the APA and the National Association of School Psychologists is one major step forward in addressing these recommendations. Further work is needed to delineate principles of “school practice competency.” We further foresee that by promoting and adopting a xeriscape model of schools, licensed psychologists and credentialed school psychologists can work together to expand the provision of educational, psychological, and mental health services in the schools to all children, guided by a model that stresses using scarce and precious resources wisely. © 2004 Wiley Periodicals, Inc. Psychol Schs 41: 461–472, 2004.
Study of two‐dimensional electron gas in AlN/GaN heterostructure by a self‐consistent method
Authors: Kong Y. C. , Zheng Y. D. , Zhou C. H. , Deng Y. Z. , Gu S. L. , Shen B. , Zhang R. , Jiang R. L. , Shi Y. , Han P.
Published: March 2004

Properties of a two‐dimensional electron gas (2DEG) in an AlN/GaN heterostructure have been studied by solving the coupled Schrödinger and Poisson equations self‐consistently. The results show that the 2DEG concentration and sheet density are 2.54 × 1020 cm−3 and 4.24 × 1013 cm−2 in the AlN/GaN structure, which are much higher than the corresponding values of 3.77 × 1019 cm−3 and 1.04 × 1013 cm−2 in an Al0.2Ga0.8N/GaN structure due to the larger band offset and the stronger piezoelectric and spontaneous polarization effects. It is also shown that the electron distribution is narrower and the subband occupation of carriers is higher in the AlN/GaN structure than in the Al0.2Ga0.8N/GaN structure. These findings make the AlN/GaN structure very attractive for use in high‐power and high‐frequency operations. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characterization of nonlinear optical parameters of copper‐ and silver‐doped silica glasses at λ = 1064 nm
Authors: Ganeev R. A. , Ryasnyansky A. I. , Stepanov A. L. , Usmanov T.
Published: March 2004

Investigations of nonlinear optical characteristics (nonlinear refractive indices, nonlinear absorption coefficients and third‐order nonlinear susceptibilities) of copper and silver nanoparticles implanted in glasses are presented using picosecond Nd:YAG laser radiation (λ = 1064 nm) and the Z‐scan technique. The variations of the sign of the nonlinear refractive indices depending on matrix properties are analyzed. It is shown that the nonlinear absorption in copper‐doped glasses is due to the two‐photon effect. The optical limiting properties of these materials are discussed in the framework of two‐photon absorption. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Covalent bridges – an induced modification of the conduction band in layered crystals
Authors: Bercha D. M. , Kharkhalis L. Yu. , Sznajder M. , Glukhov K. E.
Published: March 2004

A cross‐rearrangement of the conduction band of a layered crystal intercalated with dopant atoms which create covalent bridges is discussed. The dispersion laws (including analytical ones) of splitted subbands of the conduction band and the following rearrangement parameters have been found: characteristic concentration, width of the gap between subbands, and the energy value of the shift of the lower subband with respect to the initial position of the conduction band. The energy position of the resonant level versus parameters of the chosen model has been obtained and the conditions for this level to arise as well as its concentrational broadening were analysed. Changes of the anisotropy of the effective masses in extrema of the created subbands have been revealed. The results of investigations are in a good agreement with experimental data concerning layered In4Se3 crystals doped by copper. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nonlinear absorption of PbS nanocrystals in silicate glass
Authors: Dementjev A. , Gulbinas V. , Valkunas L. , Raaben H.
Published: March 2004

Nonlinear transient absorption of glasses doped with PbS nanocrystals was investigated by means of picosecond pump–probe absorption spectroscopy. The entire lowest energy absorption band was bleached on glass excitation at any spectral position inside this band, indicating that homogeneous broadening determines the bandwidth. Three different induced absorption mechanisms taking place at different incident light intensities were distinguished: absorption to the two‐electron–hole pair states limits absorption bleaching to about 50% of the steady‐state value at moderate excitation intensity; short‐lived absorption from the two‐electron–hole pair states appears at higher intensity when these states are populated; and two‐photon absorption occurs at very high light intensities. The two‐photon absorption populates high‐energy exciton states which relax bypassing the lowest energy exciton state. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The effect of the size distribution on the giant magnetoresistance in magnetic granular films
Authors: Wang Changzheng , Guo Zhenghong , Rong Yonghua , Hsu T. Y.
Published: March 2004

In the present paper, assuming that there is a size distribution described by the log‐normal function for the spherical granules in granular films, we take respectively the critical sizes D1(T) and D2(T) as phenomenological parameters at different temperatures distinguishing single‐domain ferromagnetic granules from superparamagnetic granules and from multi‐domain granules. Accordingly, magnetic granules can be divided into three categories: superparamagnetic, single‐domain ferromagnetic and multi‐domain ferromagnetic granules. In view of various contributions to the giant magnetoresistance (GMR) effect, the three kinds of granules are separated into two categories: first ferromagnetic granules (F1, consisting of single‐domain ferromagnetic granules), which play a key role in the GMR effect; and second ferromagnetic granules (F2, including superparamagnetic and multi‐domain granules), which play a secondary role in the GMR effect. We combine the effective medium theory with the two‐channel conducting model to study the GMR effect of granular films in detail. As a result, our calculated results are qualitatively in agreement with experimental data, showing that the theoretical method is essentially applicable for magnetic granular composites. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Theoretical studies of the angular correlation of positron annihilation in Al1− xInxN
Authors: Bousahla Z. , Abbar B. , Bouhafs B. , Tadjer A.
Published: March 2004

Angular correlation of positron annihilation radiation (ACPAR) along the (001)–(110) directions in Al1−xInxN are calculated. We observe that the momentum density distribution for different concentrations increases rapidly with increasing indium content. The computational technique used here is based on the independent particle model (IPM) coupled with the use of the electron pseudo‐wavefunction and the virtual crystal approximation (VCA), which incorporates compositional disorder as an effective potential. The variation of the positron lifetime in these alloys is also presented. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of doping on carriers of conducting polymers with degenerate ground states
Authors: Jiang F. , Li L. , George T. F. , Sun X.
Published: March 2004

Existing theory in the literature states that, in conjugated polymers with degenerate ground states, the energy of a polaron is larger than that of a soliton but smaller than that of a soliton‐antisoliton pair. However, in real polymers, doping not only provides charge transfer but also affects hopping near a dopant. Our study shows that when the hopping effect is included, the energy of a s–$ \bar {s} $ pair can be lower than that of single polaron. This effect is able to account for the experimental results observed for polymers with low concentration doping. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Anisotropic susceptibilities of thin ferromagnetic films within many‐body Green's function theory
Authors: Fröbrich P. , Kuntz P. J.
Published: March 2004

Transverse and parallel static susceptibilities of in‐plane uniaxial anisotropic ferromagnetic films are calculated using a Heisenberg model within the framework of many‐body Green's function theory. The importance of collective magnetic excitations, in particular in the paramagnetic regime, is demonstrated by comparing with mean field calculations. The paper extends the work of Jensen et al. [1] on the monolayer with spin 1/2 to the multilayer case with arbitrary spin. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Suppression of superconductivity and normal state electrical transport in Y1−xPrxBaSrCu3O7−δ and Y1−xPrxBa2Cu3O7−δ systems
Authors: Gupta Anurag , Sedky A. , Narlikar A. V.
Published: March 2004

The structure, normal state electrical transport and superconducting critical temperatures (Tc) of Y1−xPrxBaSrCu3O7−δ (i.e., Y(Pr)‐1113) and Y1−xPrxBa2Cu3O7−δ (i.e., Y(Pr)‐123) systems, with 0.00 ≤ x ≤ 1.00 and 6.93 ≤ 7 − δ ≤ 6.95, have been investigated. Residual resistivity (ρ0) and resistivity slope ((dρ/dT)cc) corresponding to the linear ρ‐T region are determined from the normal state resistivity measurements. It is found that an increase in ρ0 and (dρ/dT)cc correlates with a decrease and enhancement of Tc(x), respectively. Interestingly, in both the systems, the destruction of superconductivity seems to occur at the same value of x where (dρ/dT)cc tends to zero. The observed correlations suggest a possible mechanism of superconductivity in these systems, which is discussed. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Comment on ‘Moving screw dislocation in a piezoelectric bimaterial’ [phys. stat. sol. (b) 238, No. 1, 120–126 (2003)]
Authors: Liu Jin‐xi , Fang Dai‐ning
Published: March 2004

The original article to which this Comment refers was published in phys. stat. sol. (b) 238, No.1, 120‐126 (2003)
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A reply to this comment is published in phys. stat. sol. (b) 241, No.4, 965 (2004).

In this comment, it is pointed out that the explicit expressions of the stress and electric displacement derived by Wu et al. [phys. stat. sol. (b) 238, 120 (2003)] are incorrect. The reason for producing the erroneous results is discussed. According to Ting's work on anisotropic elastic bimaterial [Q. J. Mech. Appl. Math. 45, 119 (1992)], the correct results are given. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Reply to “Comment on ‘Moving screw dislocation in a piezoelectric bimaterial’” [phys. stat. sol. (b) 241, No. 4, 962 (2004)]
Authors: Wu Xiang‐Fa , Dzenis Yuris A.
Published: March 2004

The original article to which this Reply refers was published in phys. stat. sol. (b) 238, No.1, 120‐126 (2003)
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The Comment referred to is published in phys. stat. sol. (b) 241, No.4, 962‐964 (2004)
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In their comment, Liu and Fang pointed out two errors in our recent paper [phys. stat. sol. (b) 238, 120 (2003)]. Here we give the corrected solution, based on Suo's superposition scheme and, as can be shown, equivalent to the one given by Liu and Fang. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Photoemission study of Eu valency in EuF3 ultrathin buried layers and single crystals
Authors: Burian W. , Szade J. , O’Keevan T. , Celiński Z.
Published: March 2004

X‐ray Photoelectron Spectroscopy was used to investigate Eu valence in the following EuF3 samples: single crystal, buried MBE layers (Au/EuF3/Fe/GaAs and Au/EuF3/Fe/Ag/GaAs) and amorphous thin films. Evidence was found for a surface divalent Eu state present on single crystal and amorphous films, while the MBE ultra thin buried layers only exhibited a trivalent Eu state. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The surface band structure of W(112)
Authors: Losovyj Ya. B. , Yakovkin I. N. , Jeong Hae‐Kyung , Dowben P. A.
Published: March 2004

The cover picture of this issue is a scanning tunneling microscopy image of the furrowed W(112) surface. A number of unusual phase transitions can be observed in adlayers on such surfaces, mediated by the surface electronic structure. The electronic structure of the corrugated surface of W(112) is detailed in [1].
Modelling of the effects of continual shock loads in the transport process
Authors: Xiang Ming , Eschke R.
Published: March 2004

In the transport process, continual shock loads are typical stresses for packaged products. The studies of the effects of continual shock loads were performed on test specimens in the laboratory. The findings of these studies were used to deduce the relationship between acceleration amplitude and the number of continual shocks to failure, and a corresponding mathematical model was developed. On the basis of the individual mathematical models for the products tested, two further models were proposed for all products. This makes it possible to arrive at a better assessment of the fragility of different product types when exposed to continual shock loads. These models are capable of producing substantial cost reductions in the design of packages, as they allow the cushioning to be tailored more precisely to the fragility of the products. Copyright © 2004 John Wiley & Sons, Ltd.
Evaluation of a system for chemical sterilization of packages
Authors: Abreu L. F. , Faria J. A. F.
Published: March 2004

A system was evaluated for the chemical sterilization of packages, based on its sporicidal efficiency using inoculated Bacillus subtilis inside polyethylene terephthalate (PET) bottles. Different combinations of contact time, temperature and peracetic acid concentrations were tested, delineated according to a factorial planning of 23. The results, expressed as decimal reduction counts, proved that peracetic acid showed good sporicidal efficiency at 1.2% concentration in the temperature range 30–50°C. With this performance, the tested system can be used to sterilize plastic bottles and other similar packages, achieving a count reduction of spores by up to 10−7. Copyright © 2004 John Wiley & Sons, Ltd.
Those That Live by the Work of Their Hands: Labour, Ethnicity and Nation-State Formation in Nicaragua, 1850–1900
Authors: WOLFE JUSTIN
Published: March 2004

This study examines the relationship between labour and nation in nineteenth-century Nicaragua by exploring how the state's institutional efforts to control labour coincided with a prevailing discourse of nation that idealised farmers (agricultores) and wage labourers (jornaleros and operarios) at opposite ends of the spectrum of national citizenship. The article focuses on the towns of the ethnically diverse region of the Prefecture of Granada, an area that included the present-day departments of Granada, Carazo and Masaya, and where coffee production first boomed in Nicaragua. It is argued that labour coercion rested not simply on the building of national, regional and municipal institutions of labour control, but also on defining the political and social role of labourers within the national community. At the same time, subaltern communities, especially indigenous ones, contested these efforts not merely through evasion and subterfuge, but by engaging the discourse of nation-state to claim citizenship as farmers and assert independence from landlords.