bluuebunny/crossref_metadata_2025 huggingface dataset:
Dissociative Experiences of Women Child Abuse Survivors
Authors: Hall Joanne M.
Published: October 2003

A selective literature review of dissociation in women abuse survivors was under-taken from a feminist, constructivist perspective. Dissociation has been conceptualized many ways historically. Current understandings of dissociative phenomena are diverse, as reflected in the research and treatment literature. Dissociation has been linked to physical and psychological problems, including major mental ill-nesses, pelvic pain, somatization disorders, and eating disorders. There has been a preoccupation with rare but fascinating extremes of dissociation, such as multiple personality disorder, with less emphasis on more frequently seen types of dissociation, such as depersonalization and derealization. Views of dissociation as it occurs in women child abuse survivors affect their autonomy and perceived credibility and determine treatment trajectories. Questions remain as to what aspects and types of dissociation are “pathological.” There is evidence that dissociation may be a commonplace human experience in the general population. Implications for theory, research, and practice are included.
Democratization and Corruption
Authors: Hill Kim Quaile
Published: October 2003

The article provides evidence for a strong relationship between higher democratization and lower objective corruption levels in American state political systems. It also demonstrates that specific components of democratization thought to enhance transparency in government and probity among public officials are good predictors of lower corruption levels, whereas explicit state laws intended to reduce corruption are not.
A Population-Based Survey of Complementary and Alternative Medicine Use in Men Recently Diagnosed with Prostate Cancer
Authors: Eng Joanna , Ramsum Darlene , Verhoef Marja , Guns Emma , Davison Joyce , Gallagher Richard
Published: October 2003

Purpose:To determine prevalence and patterns of use of complementary and alternative medicine (CAM) among men recently diagnosed with prostate cancer. Study Design:Men, diagnosed with prostate cancer over a 10-month period in British Columbia, Canada, were randomly selected to obtain a population-based sample. Methods:Surveys, addressing patient demographics, types of CAM therapies, and CAM information resources utilized, reasons for use, and disclosure to physician(s), were mailed to 1108 men newly diagnosed with prostate cancer. A 42% response rate was obtained. Results:Thirty-nine percent of patients used CAM therapies with the most common being herbal supplements (saw palmetto), vitamins (vitamin E), and minerals (selenium). The most common reasons given for choosing to use CAM therapies were to (1) boost the immune system and (2) prevent recurrence. The majority of men (58%) had told their physician(s) about their CAM use, but few utilized either their family physician (15%) or their oncologist (7%) as sources of CAM information. CAM users most commonly consulted friends or family (39%) or the Internet (19%) for information about CAM. CAM users were more likely than nonusers to delay (9%) or decline (4%) conventional treatment. Respondents who had never used CAM had typically never thought about it or did not have enough information about the treatments. Conclusions:More than one third of recently diagnosed prostate cancer patients utilize some form of CAM therapy, and the majority disclose their use to their physician(s). However, they tend to rely on anecdotal information for their CAM decision making. Dissemination of reliable CAM information is one key to helping men navigate this difficult arena.
Are there differences in Breast Tissue as a Result of Hormone Replacement Therapy? Can BEST Imaging Distinguish these Differences?
Authors: Fleming R M
Published: October 2003

Although it has been speculated that estrogen therapy may promote changes in breast tissue that could lead to cancer, no information exists as to differences in breast tissue for women who do and do not take hormone replacement (HRT) therapy. This study seeks to determine if there are differences in the tissue of women taking HRT in contrast to those who do not and if these differences are apparent in cases of breast cancer, cellular atypia, fibrocystic (FCD) disease and normal breasts. A total of 327 non-pregnant, nonlactating, pre-menopausal women were enrolled in the study, including 139 women who were actively taking HRT and 188 women who never had taken HRT. Using breast enhanced scintigraphy test (BEST) imaging, differentiation of breast tissue was determined. The groups were then analyzed to determine the effect of hormone therapy within each category of breast tissue. Differentiation between normal, FCD, cellular atypia, and breast cancer represent statistically significant differences (p.001) in metabolic activity and vascularity as demonstrated by differences in both average count activity (ACA) and maximal count activity (MCA). The distinction between cellular atypia and infiltrating breast cancer was statistically (p.05) different when looking at the maximal activity. Normal breast tissue and breasts with FCD appear more homogenous with no statistical differences in variability in breast tissue. Tissue variability is statistically greater when localized processes, such as cellular atypia and breast cancer, are present. Differentiation of cellular metabolic activity in breast tissue can be statistically determined when looking at the average and maximal metabolic activity. The final distinction between cellular atypia and cancer occurs when a focal region of breast tissue becomes metabolically more active than the surrounding breast tissue as shown by statistical increases in MCA. These findings are confirmed by the increased metabolic variability seen in regions of cellular atypia and cancer compared with the homogenous metabolic activity present in normal and fibrocystic breasts.
Attending Graduate School in Adult Education and the Impact on Teaching Beliefs
Authors: Taylor Edward W.
Published: October 2003

This qualitative longitudinal study explores the impact of graduate school in adult education on practicing adult educators' beliefs about teaching. A group of practicing adult educators from several master's programs was interviewed, accompanied by an auto-photography activity, as they entered and neared completion 2 years later. Findings reveal that graduate school had only minimal impact on the teaching beliefs of participants. The majority of participants maintained significant aspects of both a teacher-centered view of teaching and a student-centered view. The only change in belief that began to emerge was a growing recognition of the importance of engaging student experience in practice. Implications for graduate school are identified and discussed.
Claiming a Sacred Face
Authors: Tisdell Elizabeth J. , Tolliver Derise E.
Published: October 2003

This article discusses the results of a study examining the role of spirituality in developing a positive cultural identity among a multicultural group of 31 adult educators and what the findings suggest for a spiritually grounded and culturally relevant approach to pedagogy. Findings of the study focus on the role of spirituality in (a) dealing with internalized oppression and reclaiming cultural identity, (b) mediating among multiple identities, (c) crossing culture to facilitate spiritual development, and (d) unconscious knowledge-construction processes that are connected to image, symbol, and ritual that are often cultural. Implications for practice include the importance of (a) the authenticity of teachers and students; (b) an environment that allows for the exploration of the cognitive, the affective or relational, and the symbolic or spiritual domains; and (c) the limitations of the adult learning environment and that transformation is an ongoing process that takes time.
Does Timing of Adjuvant Chemotherapy for Early Breast Cancer Influence Survival?
Authors: Shannon C. , Ashley S. , Smith I.E.
Published: October 2003

Purpose: Theoretically, patients with early breast cancer might benefit from starting adjuvant chemotherapy soon after surgery, and this would have important clinical implications. We have addressed this question from a large, single-center database in which the majority of patients received anthracyclines.

Patients and Methods: A total of 1,161 patients from a prospectively maintained database treated with adjuvant chemotherapy for early breast cancer at the Royal Marsden Hospital (London, United Kingdom), including 686 (59%) receiving anthracyclines, were retrospectively analyzed. The disease-free survival (DFS) and overall survival (OS) of the 368 patients starting chemotherapy within 21 days of surgery (group A) were compared with those of the 793 patients commencing chemotherapy ≥ 21 days after surgery (group B). Median follow-up time was 39 months (range, 12 to 147 months).

Results: No significant difference in 5-year DFS was found between the two groups overall (70% for group A v 72% for group B; P = .4) or in any subgroup. Likewise, there was no difference in 5-year OS (82% for group A v 84% for group B; P = .2) or when the interval to the start of chemotherapy was considered as a continuous variable (P = .4).

Conclusion: We have been unable to identify any significant survival benefit from starting adjuvant chemotherapy early after surgery, either overall or in any subset of patients.
Neural images of pursuit targets in the photoreceptor arrays of male and female housefliesMusca domestica
Authors: Burton Brian G. , Laughlin Simon B.
Published: October 2003

Male houseflies use a sex-specific frontal eye region, the lovespot, to detect and pursue mates. We recorded the electrical responses of photoreceptors to optical stimuli that simulate the signals received by a male or female photoreceptor as a conspecific passes through its field of view. We analysed the ability of male and female frontal photoreceptors to code conspecifics over the range of speeds and distances encountered during pursuit, and reconstructed the neural images of these targets in photoreceptor arrays. A male's lovespot photoreceptor detects a conspecific at twice the distance of a female photoreceptor, largely through better optics. This detection distance greatly exceeds those reported in previous behavioural studies. Lovespot photoreceptors respond more strongly than female photoreceptors to targets tracked during pursuit, with amplitudes reaching 25 mV. The male photoreceptor also has a faster response, exhibits a unique preference for stimuli of 20-30 ms duration that selects for conspecifics and deblurs moving images with response transients. White-noise analysis substantially underestimates these improvements. We conclude that in the lovespot, both optics and phototransduction are specialised to enhance and deblur the neural images of moving targets, and propose that analogous mechanisms may sharpen the neural image still further as it is transferred to visual interneurones.
Adaptations to diving hypoxia in the heart, kidneys and splanchnic organs of harbor seals (Phoca vitulina)
Authors: Fuson Amanda L. , Cowan Daniel F. , Kanatous Shane B. , Polasek Lori K. , Davis Randall W.
Published: October 2003

Pinnipeds (seals and sea lions) have an elevated mitochondrial volume density [VV(mt)] and elevated citrate synthase (CS) andβ-hydroxyacyl-CoA dehydrogenase (HOAD) activities in their swimming muscles to maintain an aerobic, fat-based metabolism during diving. The goal of this study was to determine whether the heart, kidneys and splanchnic organs have an elevated VV(mt) and CS and HOAD activities as parallel adaptations for sustaining aerobic metabolism and normal function during hypoxia in harbor seals (Phoca vitulina). Samples of heart,liver, kidney, stomach and small intestine were taken from 10 freshly killed harbor seals and fixed in glutaraldehyde for transmission electron microscopy or frozen in liquid nitrogen for enzymatic analysis. Samples from dogs and rats were used for comparison. Within the harbor seal, the liver and stomach had the highest VV(mt). The liver also had the highest CS activity. The kidneys and heart had the highest HOAD activities, and the liver and heart had the highest lactate dehydrogenase (LDH) activities. Mitochondrial volume densities scaled to tissue-specific resting metabolic rate [VV(mt)/RMR] in the heart, liver, kidneys, stomach and small intestine of harbor seals were elevated (range 1.2-6.6×) when compared with those in the dog and/or rat. In addition, HOAD activity scaled to tissue-specific RMR in the heart and liver of harbor seals was elevated compared with that in the dog and rat (3.2× and 6.2× in the heart and 8.5× and 5.5× in the liver, respectively). These data suggest that organs such as the liver, kidneys and stomach possess a heightened ability for aerobic, fat-based metabolism during hypoxia associated with routine diving. However, a heightened LDH activity in the heart and liver indicates an adaptation for the anaerobic production of ATP on dives that exceed the animal's aerobic dive limit. Hence, the heart, liver, kidneys and gastrointestinal organs of harbor seals exhibit adaptations that promote an aerobic, fat-based metabolism under hypoxic conditions but can provide ATP anaerobically if required.
A two-level optimization feature for the design of aerospace structures
Authors: Carrera E , Mannella L , Augello G , Gualtieri N
Published: October 2003

This work proposes and applies a two-level optimization feature for the design and analysis of reinforced shell structures for aerospace applications. A general-purpose finite element software (NASTRAN) is used as a first-level code to compute the loadings that act on panels. The panels are then optimized using a second-level code (PANDA2), which gives their optimum solutions by taking into account buckling and postbuckling elastic stability constraints. The PANDA2 code, which is based on pseudo-analytical formulations, leads to a considerable reduction of the requested computational efforts compared to the optimization made by NASTRAN. The proposed two-level feature, named NAPAO, builds a loop (between the NASTRAN and PANDA2 codes) that runs until a convergent solution is reached. Those substructures, such as longerons and stiffeners (which are not considered by PANDA2), could be optimized by referring to the solver that is available from NASTRAN. A number of examples that encompass simple structures as well as two complete space vehicles and an unconventional aircraft have been optimized. Metallic as well as composite materials were considered. It can be concluded that NAPAO is a very useful tool for the design process of complex aerospace structures. It gives accurate results and reduces computational costs compared to a standard optimization made when only using the general-purpose code.
Discourses about ethnic group (de‐)essentialism: Oppressive and progressive aspects
Authors: Verkuyten Maykel
Published: October 2003

Social psychologists studying intergroup perceptions have shown an increasing interest in essentialist thinking. Essentialist beliefs about social groups are examined as cognitive processes and these beliefs would serve to rationalize and justify the existing social system. Discourse analyses on racism have emphasized that problems of racism are to a large extent problems of essentialism. Anti‐essentialism has emerged as an emancipatory discourse in the challenge of hegemonic representations and oppressive relations. The present study examines how, in group discussions, ethnic Dutch and ethnic minority people define and use essentialist notions about social groups. Both Dutch and ethnic minority participants engaged in an essentialist discourse in which an intrinsic link between culture and ethnicity was made. However, there were also examples where this discourse was criticized and rejected. This variable use of (de‐)essentialism is examined in terms of the conversation's context and issues at hand, such as questions of assimilation, group provisions, cultural rights, and agency. The main conclusion of this paper is that essentialism is not by definition oppressive and that de‐essentialism is not by definition progressive. The discursive power of (de‐)essentialist group beliefs depends on the way they are used and the context in which they appear.
Influence of the Nozzle Geometry on Spray‐Dried Particle Formation Expanding Superheated Suspensions
Authors: Monse K. , Linnepe T. , Groom S. , Walzel P.
Published: October 2003

Expanding a superheated solution or suspension to ambient atmosphere leads to a flash evaporation as a part of the pure liquid evaporates. If a superheated solution or suspension is atomized into a spray dryer working under atmospheric conditions, the particles formed are smaller than the particles resulting from nonsuperheated suspensions. The amount of air needed to dry the particles is reduced and the filters or cyclones installed for exhaust gas cleaning can be operated at lower pressure drop. Because of the decreased amount of drying air, the energy losses are also reduced.
Sum rules and exact relations for quantal Coulomb systems
Authors: Adamyan V.M. , Tkachenko I.M.
Published: October 2003

A complex response function describing a reaction of a multi‐particle system to a weak alternating external field is the boundary value of a Nevanlinna class function (i.e. a holomorphic function with non‐negative imaginary part in the upper half‐plane). Attempts of direct calculations of response functions based on standard approximations of the kinetic theory for real Coulomb condensed systems often result in considerable discrepancies with experiments and computer simulations. At the same time a relatively simple approach using only the exact values of leading asymptotic terms of the response function permits to restrict essentially a subset of Nevanlinna class functions containing this response function, and in this way to obtain sufficient data to explain and predict experimental results. Mathematical details of this approach are demonstrated on an example with the response function being the (external) dynamic electrical conductivity of cold dense hydrogen‐like plasmas. In particular, the exact values of the leading terms of asymptotic expansions of the conductivity are calculated. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
How correct is the EOS of weakly nonideal hydrogen plasmas?
Authors: Starostin A.N. , Roerich V.C. , More R.M.
Published: October 2003

Helioseismology opens new possibility to check EOS of weakly nonideal hydrogen plasmas with high precision, using reconstructed local sound velocities within 10‐4 accuracy. A comparison of different theoretical models with experiment permits to verify the existing methods of calculation bound states and continuum contribution to the second virial coefficient within the framework of physical nature. The regular way of the deduction expression for EOS is presented and generalization of the EOS for broad atomic states and two temperature non‐equilibrium case is proposed. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Cyclic Voltammetry Examination for Effect of Counter Anion on Adsorptive Voltammetry of 11‐Ferrocenytrimethylundecylammonium at Carbon Paste Electrode
Authors: Hattori Toshiaki , Tanaka Shunitz
Published: October 2003

The electrode oxidation of 11‐ferrocenyltrimethylundecylammonium (FeTMUA) at carbon paste electrode (CPE) was investigated by cyclic voltammetry in order to reveal the adsorption nature of FeTMUA ion‐paired with anion. The voltammograms of FeTMUA were classified by the counter anion; hydrophilic and hydrophobic ions. The electric charge reflecting the adsorption isotherm increased gently with the FeTMUA concentration until a critical point (CP), which was independent of the sort of hydrophilic anion and comparable with the amount of the maximum surface coverage of FeTMUA at the air‐water interface. The voltammogram for hydrophobic anion had two oxidation waves. The electric charge for the first wave monotonously increased with the FeTMUA concentration without indicating CP. The second wave was not observed on the voltammogram at the glassy carbon electrode, thus the second wave was made from the pasting liquid. These results suggested that CPE adsorbed FeTMUA with hydrophilic anion behaved like serving a liquid surface, however, CPE adsorbed FeTMUA with hydrophobic anion was disordered and represented the heterogeneity.
Cost Comparison of Protein Capture from Cultivation Broths by Expanded and Packed Bed Adsorption
Authors: Curbelo D.R. , Garke G. , Guilarte R.C. , Anspach F.B. , Deckwer W.‐D.
Published: October 2003

In the downstream processing of recombinant protein production, the reduction of unit operations required for product capture and purification, is of the utmost priority due to its cost diminishing effect. In this regard, target protein capture from cell suspensions in a fluidized bed of affinity particles with different sizes (expanded bed adsorption (EBA) with classified particles), presents an efficient tool since EBA may substitute cell disintegration, separation by centrifugation or filtration, and packed bed adsorption. However, as illustrated by experiments with the BSA/yeast cells system, the entire broth processing used in EBA also has detrimental influences due to the cell (or cell debris) binding on the affinity carrier. In particular, external mass transfer may become more dominant, and the lifetime of the affinity particles may reduce as a result of other cleaning procedures. Using simulations performed with a commercial software package, the cost superiority of alternate process routes (EBA or packed bed adsorption with preceding steps) can be evaluated. This elucidates the favorable application range for each route.
Temperature fluctuation under bubbles of pool boiling in decompression
Authors: Sekine Ikuhei
Published: October 2003

Experiments on pool boiling of water were performed under decompression. Temperature fluctuation was measured with three thermocouples which were equipped on the copper block surface by plating. Rapid temperature drops in this fluctuation arise at the same times. This shows the existence of evaporation of the microlayer under bubbles. Evaluation of this evaporation of the microlayer and rapid temperature drops revealed the existence of a new evaporation factor in obedience to the liquid surface overheating. Temperature drops are of two types at decompression. One is rapid drop due to cavity existence and the other is slow drop due to generation in the superheated bulk liquid on the mirror surface. This rapid temperature drop is gradual at the first stage. For verification of gradual drops, we introduced an equation concerning micro film thickness under the bubble on the basis of the viscosity and the preservation of momentum. This equation has an exponential factor for microfilms. Numerical calculations showed good agreement with the experimental data. © 2003 Wiley Periodicals, Inc. Heat Trans Asian Res, 32(7): 567–581, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.10102
Laser‐assisted fabrication of monomode polymer waveguides and their optical characterization
Authors: Pfleging W. , Finke S. , Gaganidze E. , Litfin K. , Steinbock L. , Heidinger R.
Published: October 2003

The local surface modification as well as the direct micro‐ablation of polymethylmethacrylate (PMMA) with UV‐laser radiation was studied with respect to the fabrication of optical monomode waveguides. Different UV sources were applied with a focus on excimer lasers and frequency‐multiplied Nd:YAG lasers to investigate several concepts of integrated waveguides. One type of waveguides is realized by localized physical modification, which leads in one step to an integrated polymer waveguide with higher refractive index. A complementary type of waveguides includes the formation of small grooves, which are filled with index matched materials introducing a micro‐scaled increase or decrease of the refractive index into the original PMMA substrate. The different laser‐assisted fabrication techniques for polymer waveguide formation as well as the characterization of their local optical properties are discussed in detail.
Mikrotribometrie im Maschinenbau
Authors: Scherge M. , Gervé A.
Published: October 2003

Bei der mikrotribometrischen Analyse von Makrosystemen muß darauf geachtet werden, dass auf der Mikroskala gewonnene Werte für Reibungskoeffizient und Verschleiß nur bedingt auf die Makroskala skalierbar sind. Aufgrund fehlender Ähnlichkeit in energetischer Hinsicht sowie unzureichender Statistik durch die Beschränkung auf Einzelkontakte sollten mikrotribologische Verfahren bevorzugt zur Analyse von wichtigen Begleiteffekten, wie zum Beispiel der physikalisch‐chemischen Veränderung des oberflächennahen Bereichs, herangezogen werden. Das mikrotribologische Experiment muß dabei in ein Netzwerk von oberflächenphysikalischen Methoden und Verfahren der Mikrostrukturanalyse integriert sein.
Friction Behaviour and Wear Properties of Rail and Wheel Material
Authors: Deters L. , Proksch M.
Published: October 2003

Experimental examinations of the friction behaviour and the wear properties of rail and wheel material are reported. The two roller contact is selected as the testing principle to simulate the wheel‐to‐rail contact. Wear tests were performed on a new designed test machine. The wear volume rise turned out to be proportional to the increase of the acting pressure and the creep between the rollers. Raising the circumferential speed of the test rollers caused a reduction in the wear volume. A significant wear decrease at the driven rail rollers could be achieved by periodically reversing the direction of the acting friction forces. Examinations as to the extent to which experimental results can be applied to practice, reveal a good correspondence.
Tribological Tayloring of Ceramic Composites
Authors: Wäsche R. , Klaffke D. , Yarim R. , Santner E.
Published: October 2003

With respect to their excellent material properties ceramics are of interest as candidate materials for tribological applications. The friction and wear behaviour of ceramics is often superior to that of metallic materials. Furthermore, an essential improvement of tribological performance will be possible by tailoring of ceramics in the process of powder preparation and sintering technique. Silicon Carbide (SiC) shows interesting friction and wear behaviour at room temperature, even under unlubricated running conditions but is very sensitive against effects of environmental humidity and shows high friction and high wear in the absence of water vapour. The tribological performance of SiC can be improved considerably by adding substantial amounts of TiC and TiB2 to the microstructure thus creating ceramic particulate composite materials.

Various composites in the quasi ternary system SiC‐TiC‐TiB2 were prepared by a ceramic manufacturing process including sintering temperatures up to 2180 °C. Comparative tribo tests were performed under unlubricated oscillating sliding motion in dry, normal, and moist air and under water lubrication with SiC balls and Al2O3 balls as counter bodies. The friction is affected by the relative humidity (RH) but barely at all by the composition of the composites. The wear resistance of the composites was found to be improved considerably by addition of TiB2 in the range from 20 to 60 %. The highest wear resistance of the system wear was found when Al2O3 was used as counter body material.
Charge transport, injection, and photovoltaic phenomena in oligo(phenylenevinylene) based diodes
Authors: Melzer Christian , Krasnikov Victor V. , Hadziioannou Georges
Published: October 2003

We report on the charge transport and injection phenomena of (E,E,E,E)‐1,4‐bis[(4‐styryl)styryl]‐2‐methoxy‐5‐(2′‐ethylhexoxy)benzene (MEH‐OPV5) sandwiched between asymmetric contacts. The hole mobility of MEH‐OPV5 was determined by means of transient electroluminescence. The steady‐state current was injection‐limited. The electric field and temperature dependence of the current were quantitatively described by a phenomenological injection model of thermally assisted charge‐carrier tunneling in a one‐dimensional chain of hopping sites. Furthermore, we report on the photovoltaic properties of thin‐film photovoltaic cells on the basis of donor–acceptor heterojunctions. MEH‐OPV5 and buckminster fullerene were used as the donor and acceptor materials, respectively. The emphasis was on the role of morphology in such devices. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2665–2673, 2003
Charge‐carrier transport in disordered polymers
Authors: Novikov S. V.
Published: October 2003

The general properties of charge‐carrier transport in disordered organic materials are discussed. The spatial correlation between energies of transport sites determined the form of drift‐mobility field dependence. The type of spatial correlation in a disordered material depends on its nature. Mobility field dependences must be different in polar and nonpolar materials. Different methods of mobility calculation from the shape of photocurrent transient were analyzed. A widely used method is very sensitive to the variation of the shape of the transient and sometimes produces results that effectively masquerade the true dependence of the mobility on the electric field or trap concentration. Arguments in favor of the better, more reliable method are suggested. Charge transport in materials containing charged traps was considered without using the isolated trap approximation, and this led to qualitatively different results. The results indicated that the effect of charged traps can hardly be responsible for the experimentally observed transport properties of disordered organic materials. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2584–2594, 2003
Problem‐Based Learning in an MBA Economics Course: Confessions of a First‐Time User
Authors: Sharp David C.
Published: October 2003

Professors who have never used problem‐based learning (PBL) may need advice to support their first attempts. These professors can benefit from the confessions of one first‐time (and initially reluctant) PBL user.
Assessing Students' Problem‐Solving Assignments
Authors: Anderson Rebecca S. , Puckett Jane B.
Published: October 2003

Professors can use rubrics as a valuable evaluation tool with probelm‐based learning activities. In this article, we guide professors through the process of rubric development.
The ketamine model for schizophrenia
Authors: Alpert Murray , Angrist Burt
Published: October 2003

This commentary compares clinical aspects of ketamine with the amphetamine model of schizophrenia. Hallucinations and loss of insight, associated with amphetamine, seem more schizophrenia-like. Flat affect encountered with ketamine is closer to the clinical presentation in schizophrenia. We argue that flat affect is not a sign of schizophrenia, but rather, arisk factorfor chronic schizophrenia.
Spatial integration in perception and cognition: An empirical approach to the pathophysiology of schizophrenia
Authors: Chen Yue
Published: October 2003

Evidence for a dysfunction in cognitive coordination in schizophrenia is emerging, but it is not specific enough to prove (or disprove) this long-standing hypothesis. Many aspects of the external world are spatially mapped in the brain. A comprehensive internal representation relies on integration of information across space. Focus on spatial integration in the perceptual and cognitive processes will generate empirical data that shed light on the pathophysiology of schizophrenia.
Inferring contextual field interactions from scalp EEG
Authors: Pflieger Mark E.
Published: October 2003

This commentary highlights methods for using scalp EEG to make inferences about contextual field interactions, which, in view of the target article, may be specially relevant to the study of schizophrenia. Although scalp EEG has limited spatial resolution, prior knowledge combined with experimental manipulations may be used to strengthen inferences about underlying brain processes. Both spatial and temporal context are discussed within the framework of nonlinear interactions. Finally, results from a visual contour integration EEG pilot study are summarized in view of a hypothesis that relates receptive field and contextual field processing to evoked and induced activity, respectively.
Cortical connectivity in high-frequency beta-rhythm in schizophrenics with positive and negative symptoms
Authors: Strelets Valeria
Published: October 2003

In chronic schizophrenic patients with both positive and negative symptoms (see Table 1), interhemispheric connections at the high frequency beta2-rhythm are absent during cognitive tasks, in contrast to normal controls, who have many interhemispheric connections at this frequency in the same situation. Connectivity is a fundamental brain feature, evidently greatly promoted by the NMDA system. It is a more reliable measure of brain function than the spectral power of this rhythm.
High-frequency synchronisation in schizophrenia: Too much or too little?
Authors: Williams Leanne M. , Lee Kwang-Hyuk , Haig Albert , Gordon Evian
Published: October 2003

Phillips & Silverstein's focus on schizophrenia as a failure of “cognitive coordination” is welcome. They note that a simple hypothesis of reduced Gamma synchronisation subserving impaired coordination does not fully account for recent observations. We suggest that schizophrenia reflects a dynamic compensation to a core deficit of coordination, expressed either as hyper- or hyposynchronisation, with neurotransmitter systems and arousal as modulatory mechanisms.
Cognitive coordination and its neurobiological bases: A new continent to explore
Authors: Silverstein Steven M. , Phillips William A.
Published: October 2003

The additional arguments and evidence supplied by the commentaries strengthen the hypothesis that underactivity of NMDA receptors produces impaired cognitive coordination in schizophrenia. This encourages the hope that though the distance from molecules to mind is great, it can nevertheless be traversed. We therefore predict that in this decade or the next molecular psychology will be seen to be as fundamental to our understanding of mind as molecular biology is to our understanding of life.
STOCHASTIC SCHEDULING WITH PREEMPTIVE-REPEAT MACHINE BREAKDOWNS
TO MINIMIZE THE EXPECTED WEIGHTED FLOW TIME
Authors: Cai Xiaoqiang , Sun Xiaoqian , Zhou Xian
Published: October 2003

We study a stochastic scheduling problem with a single machine
subject to random breakdowns. We address the
preemptive-repeat model; that is, if a breakdown occurs
during the processing of a job, the work done on this job is
completely lost and the job has to be processed from the beginning
when the machine resumes its work. The objective is to complete
all jobs so that the the expected weighted flow time is minimized.
Limited results have been published in the literature on this
problem, all with the assumption that the machine uptimes are
exponentially distributed. This article generalizes the study
to allow that (1) the uptimes and downtimes of the machine follow
general probability distributions, (2) the breakdown patterns
of the machine may be affected by the job being processed and
are thus job dependent; (3) the processing times of the jobs
are random variables following arbitrary distributions, and
(4) after a breakdown, the processing time of a job may either
remain a same but unknown amount, or be resampled according
to its probability distribution. We derive the necessary and
sufficient condition that ensures the problem with the flow-time
criterion to be well posed under the preemptive-repeat breakdown
model. We then develop an index policy that is optimal for the
problem. Several important situations are further considered
and their optimal solutions are obtained.
ON THE WORKLOAD PROCESS IN A FLUID QUEUE WITH A RESPONSIVE
BURSTY INPUT AND SELECTIVE DISCARDING
Authors: Dube Parijat , Altman Eitan
Published: October 2003

We analyze a feedback system consisting of a finite buffer
fluid queue and a responsive source. The source alternates between
silence periods and active periods. At random epochs of times,
the source becomes ready to send a burst of fluid. The length
of the bursts (length of the active periods) are independent
and identically distributed with some general distribution.
The queue employs a threshold discarding policy in the sense
that only those bursts at whose commencement epoch (the instant
at which the source is ready to send) the workload (i.e., the
amount of fluid in the buffer) is less than some preset threshold
are accepted. If the burst is rejected then the source backs
off from sending. We work within the framework of Poisson
counter-driven stochastic differential equations and obtain
the moment generating function and hence the probability density
function of the stationary workload process. We then comment
on the stability of this fluid queue. Our explicit
characterizations will further provide useful insights and
“engineering” guidelines for better network designing.
Should patients manage their own oral
anticoagulation therapy?
Authors: Marzonlini M , Wynne Hilary
Published: October 2003

Oral anticoagulant therapy has become more commonly prescribed for people of 65 years and over following the widening of its clinical indications to include thromboembolic prophylaxis in atrial fibrillation. It is estimated that approximately 470 000 people in the UK, almost 1% of the population, are currently receiving oral anticoagulant therapy and this is growing. Due to its narrow therapeutic index, and the intra-individual variation in dose requirement, there is a need to monitor the level of anticoagulation in each patient. In consequence, health systems have had to invest resources into monitoring services to cope with this development.
Epilepsy
Authors: Tallis Raymond C
Published: October 2003

Many doctors have the impression that elderly-onset epilepsy is uncommon. This has no basis in the recent literature. There is evidence from many countries e.g. USA, Denmark, that the incidence of seizures rises sharply in old age. The United Kingdom National General Practice Survey of Epilepsy and Epileptic Seizures (NGPSE), a prospective-based, community-based study found that 24% of new cases of definite epilepsy were in subjects over the age of 60. A study of a primary care database covering 82 practices and nearly 370 000 subjects, 62 000 of whom were over the age of 60, revealed a continuing rise in the incidence of seizures in old age, whereas the incidence for the overall population was 69 per
100 000, the incidence in the 65 to 69 age group was 87, in the 70s, 147 per 100 000, and in the 80s, 159 per 100 000. Over one-third of all incident cases placed on antiepileptic drugs (AEDs) were individuals over the age of 60.
Background rareness-based iterative multiple sequence alignment algorithm for regulatory element detection
Authors: Narasimhan Chandrasegaran , LoCascio Philip , Uberbacher Edward
Published: October 2003

Motivation: Experimental methods capable of generating sets of co-regulated genes have become commonplace, however, recognizing the regulatory motifs responsible for this regulation remains difficult. As a result, computational detection of transcription factor binding sites in such data sets has been an active area of research. Most approaches have utilized either Gibbs sampling or greedy strategies to identify such elements in sets of sequences. These existing methods have varying degrees of success depending on the strength and length of the signals and the number of available sequences. We present a new deterministic iterative algorithm for regulatory element detection based on a Markov chain background. As in other methods, sequences in the entire genome and the training set are taken into account in order to discriminate against commonly occurring signals and produce patterns, which are significant in the training set.

Results: The results of the algorithm compare favorably with existing tools on previously known and newly compiled data sets. The iteration based search appears rather rigorous, not only finding the binding sites, but also showing how the binding site stands out from genomic background. The approach used to score the results is critical and a discussion of various scoring schemes and options is also presented. Benchmarking of several methods shows that while most tools are good at detecting strong signals, Gibbs sampling algorithms give inconsistent results when the regulatory element signal becomes weak. A Markov chain based background model alleviates the drawbacks of MAP (maximum a posteriori log likelihood) scores.

Availability: Available on request from the authors.

Supplementary information: Data and the results presented in this paper are available on the web at http://compbio.ornl.gov/mira/index.html
A Nonlinear Dynamical Model for Ultrafast Catalytic Transfer of Electrons at Zero Temperature
Authors: Aubry S. , Kopidakis G.
Published: October 2003

The complex amplitudes of the electronic wavefunctions on different sites are used as Kramers variables for describing Electron Transfer. The strong coupling of the electronic charge to the many nuclei, ions, dipoles, etc, of the environment, is modeled as a thermal bath better considered classically. After elimination of the bath variables, the electron dynamics is described by a discrete nonlinear Schrödinger equation with norm preserving dissipative terms and Langevin random noises (at finite temperature). The standard Marcus results are recovered far from the inversion point, where atomic thermal fluctuations adiabatically induce the electron transfer. Close to the inversion point, in the non-adiabatic regime, electron transfer may become ultrafast (and selective) at low temperature essentially because of the nonlinearities, when these are appropriately tuned. We demonstrate and illustrate numerically that a weak coupling of the donor site with an extra appropriately tuned (catalytic) site, can trigger an ultrafast electron transfer to the acceptor site at zero degree Kelvin, while in the absence of this catalytic site no transfer would occur at all (the new concept of Targeted Transfer initially developed for discrete breathers is applied to polarons in our theory). Among other applications, this theory should be relevant for describing the ultrafast electron transfer observed in the photosynthetic reaction centers of living cells.
Some Applications of a Driven Nonlinear Lattice: Statistical Properties of Turbulence and Control of Thermal Flow
Authors: Peyrard Michel
Published: October 2003

A nonlinear lattice driven by both ends is an interesting system to study two different physical problems: the statistical properties of turbulence and the control of the thermal flow in a solid state device. Both of these applications rely on nonlinearity that couples modes, shifts their vibrational frequencies, and, in a lattice, allows for the existence of discrete breathers. By introducing a special form of dissipation that mimics viscosity, we can show that such a nonlinear lattice exhibits properties which are strikingly similar to various experimental results obtained in a turbulent von Kármán flow, while an appropriate choice of parameters allows a precise control of the heat flow in the lattice, and can even turn the system into a "thermal rectifier" which does not have the same thermal conductivity in the two directions. By providing a model sufficiently simple to be studied in details the application to turbulence may suggest some clues to understand general features of turbulence, while the possibility to control and direct a thermal flow, although it is still very far from a practical device, could open new possibilities for applications.
Depinning Transition as a Critical Phenomenon
Authors: Roux Stéphane , Vandembroucq Damien
Published: October 2003

Extremal modelling of pinning problems is introduced, and discussed for some applications. Some scaling properties of the system at the onset of depinning are presented, and shown to be universal. Relations between the static morphology of the front, the dynamic spreading of activity, and the statistical distribution of depinning forces are presented.
Nonsequence Double Ionization of Helium and Correlated Electron Emission
Authors: Fu Li-Bin , Liu Jie , Chen Shi-Gang
Published: October 2003

In this paper, a quasistatic model is extended to describe the double ionization of Helium in intense linearly polarized field. Our numerical calculations reproduce the excessive double ionization and the photoelectron spectra observed experimentally both quantitatively and qualitatively. Moreover, the correlation between magnitude and direction of momentum in the polarization axis of two emission electrons has been studied.
Global Instability, Limiting-State Selection and Nonlinear Pattern Formation
Authors: Xu Jian-Jun , Huang Yong-Nian
Published: October 2003

Interfacial pattern formation in phase transition and crystal growth and material science is one of the most important subjects in the broad field of nonlinear science. This subject involves the concepts and issues, include the basic states, global stability, limiting-state selection, quantization conditions of eigenvalues, scaling law and free boundary problems of dynamic system far away from the equilibrium state.

This talk attempts to explore these issues through the two prototype problems: (1). dendritic growth from melt; (2). disc-like crystal growth from melt. These problems are highly challenging fundamental problems in condensed matter physics and material science, which have preoccupied many investigators from various areas of science, including applied mathematics for a long period of time.

We shall summarize the major results achieved in terms of a unified systematic asymptotic approach during the last decade. For the case of dendritic growth, these results described the wave-characteristics of interface evolution and led to the so-called interfacial wave (IFW) theory.
Interactive shadow generation in complex environments
Authors: Govindaraju Naga K. , Lloyd Brandon , Yoon Sung-Eui , Sud Avneesh , Manocha Dinesh
Published: October 2003

We present a new algorithm for interactive generation of hard-edged, umbral shadows in complex environments with a moving light source. Our algorithm uses a hybrid approach that combines the image quality of object-precision methods with the efficiencies of image-precision techniques. We present an algorithm for computing a compact potentially visible set (PVS) using levels-of-detail (LODs) and visibility culling. We use the PVSs computed from both the eye and the light in a novel cross-culling algorithm that identifies a reduced set of potential shadow-casters and shadow-receivers. Finally, we use a combination of shadow-polygons and shadow maps to generate shadows. We also present techniques for LOD-selection to minimize possible artifacts arising from the use of LODs. Our algorithm can generate sharp shadow edges and reduces the aliasing in pure shadow map approaches. We have implemented the algorithm on a three-PC system with NVIDIA GeForce 4 cards. We achieve 7--25 frames per second in three complex environments composed of millions of triangles.