bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of hybrid network formation on adhesion properties of polycyanurate/polyurethane semi‐interpenetrating polymer networks
Authors: Grigoryeva O. , Fainleib A. , Pissis P. , Boiteux U.
Published: April 2004

The adhesion characteristics of modified polycyanurates based on the principle of semi‐interpenetrating polymer networks (semi‐IPNs) have been studied. It has been shown that the formation of a polycyanurate network in the presence of linear polyurethane (LPU) leads to increasing adhesion strength to aluminum and titanium. The peculiarities of polycyanurate network (PCN) formation in the presence of different amounts of LPU are discussed. It has been found that chemical incorporation of LPU into PCN occurs during network formation owing to chemical interaction of urethane groups with cyanate groups of growing PCN. At LPU content in the initial composition up to around 20 wt% only a hybrid network is formed. The maximal values of adhesive strength to aluminum and titanium are achieved at LPU content of 20–25%, corresponding to formation of a hybrid network. The further increase of LPU content leads to the presence of non‐incorporated LPU (semi‐IPN formation) in the adhesive layer and to reduction of the adhesive strength.
Effects of temperature and strain rate on the tensile behavior of unfilled and talc‐filled polypropylene. Part I: Experiments
Authors: Zhou Yuanxin , Mallick P. K.
Published: April 2004

The tensile behavior of unfilled and 40 w% talc‐filled polypropylene has been determined at four different temperatures (21.5, 50, 75 and 100°C) and three different strain rates (0.05, 0.5 and 5 min−1). Experimental results showed that both unfilled and talc‐filled polypropylenes were sensitive to strain rate and temperature. Stressstrain curves of both materials were nonlinear even at relatively low strains. The addition of talc to polypropylene increased the elastic modulus, but the yield strength and yield strain were reduced. The temperature and strain rate sensitivities of these materials were also different. An energy‐activated, rate sensitive Eyring equation was used to predict the yield strength of both materials. It is shown that both activation volume and activation of energy increased with the addition of talc in polypropylene.
Effects of temperature and strain rate on the tensile behavior of unfilled and talc‐filled polypropylene. Part II: Constitutive equation
Authors: Zhou Yuanxin , Mallick P. K.
Published: April 2004

Based on the experimental results presented in Part I of this research, a three parameter nonlinear constitutive model has been proposed to describe the strain rate and temperature dependent tensile behaviors of unfilled and talc‐filled polypropylene. One of the parameters is the elastic modulus. The other two parameters in this model are a strain exponent, m, and a compliance factor, β. Their relationships to strain rate and temperature are obtained from the experimental results. The simulated stress‐strain curves from the model are in good agreement with the test data. The analysis of the model shows that the strain exponent m, which controls the strain softening (or hardening) effect of the material, is not only strain rate independent, but also temperature independent. The compliance parameter, β, which controls the flow stress level of the material, on the other hand, varies with both strain rate as well as temperature. Results also show that the addition of talc filler in polypropylene reduces the strain exponent m, and increase the compliance parameter, β, which reduces the flow stress level of talc‐filled polypropylene to lower than that of unfilled polypropylene.
Development of rapid heating and cooling systems for injection molding applications
Authors: Yao Donggang , Kim Byung
Published: April 2004

The injection molding process has several inherent problems associated with the constant temperature mold. A basic solution is the rapid thermal response molding process that facilitates rapid temperature change at the mold surface thereby improving quality of molded parts without increasing cycle time. Rapid heating and cooling systems consisting of one metallic heating layer and one oxide insulation layer were investigated in this paper. Design issues towards developing a mold capable of raising temperature from 25°C to 250°C in 2 seconds and cooling to 50°C within 10 seconds were discussed. To reduce thermal stresses in the layers during heating and cooling, materials with closely matched low thermal expansion coefficient were used for both layers. Effects of various design parameters, such as layer thickness, power density and material properties, on the performance of the insert were studied in detail with the aid of heat transfer simulation and thermal stress simulation. Several rapid thermal response mold inserts were constructed on the basis of the simulation results. The experimental heating and cooling response agrees with the simulation and also satisfies the target heating and cooling requirement.
Synthesis and insecticidal activity of 5‐acyloxyimino‐5‐deoxyavermectin B1 derivatives
Authors: Xiguang Liu , Jingping Wu , Xiaomei Liang , Daoquan Wang
Published: April 2004

Four novel 5‐acyloxyimino‐5‐deoxyavermectin B1 compounds have been synthesized from avermectin B1 by selective oxidization of the hydroxy group at C‐5, followed by oximation and convenient esterification. Their structures were confirmed by IR, 1H NMR, 13C NMR and MS. Insecticidal activities of the intermediate oxime and the four new acyl derivatives were evaluated against Helicoverpa armigera, Spodoptera exigua and Musca domestica. Copyright © 2004 Society of Chemical Industry
Tebuconazole dissipation and metabolism in Tifton loamy sand during laboratory incubation
Authors: Strickland Timothy C , Potter Thomas L , Joo Hyun
Published: April 2004

The fungicide tebuconazole is widely used to control soil‐borne and foliar diseases in peanuts and other crops. No published data are currently available on the extent and rate at which this compound degrades in soil. Unpublished data summarized in registration documents suggest that the compound is persistent, with 300–600 days half‐life. We conducted a 63‐day laboratory incubation to evaluate tebuconazole's dissipation kinetics and impact on soil microbial activity in Tifton loamy sand. Tifton soils support extensive peanut production in the Atlantic Coastal Plain region of Georgia and Alabama. Products containing tebuconazole are applied to an estimated 50% of the peanut acreage in the region. At the end of the incubation, 43 (±42)% of the parent compound was recovered in soil extracts. The first‐order kinetic model, which gave a good fit to the dissipation data (r2 = 0.857), yielded a soil half‐life (t1/2) of 49 days. This is 6–12 times more rapid than t1/2 values described in unpublished tebuconazole registration documents. Four degradates were identified. Tentative structural assignments indicated that degradates were derived from hydroxylation of the parent compound and/or chlorophenyl ring cleavage. Cleavage products showed a steady increase during the incubation, and on a molar basis were equal to 63% of the time zero tebuconazole concentration. No significant effect on soil microbial biomass was observed, indicating that when the compound is applied at normal agronomic rate it does not impact soil metabolic activity. Use of the soil‐half life data derived in this study should improve the accuracy of tebuconazole fate assessments for Coastal Plain peanut production. The study also indicated that environmental assessment of selected degradates may be needed to fully evaluate risks of tebuconazole use. Published in 2004 for SCI by John Wiley & Sons, Ltd.
Effect of exposure period on degree of dominance of phosphine resistance in adults of Rhyzopertha dominica (Coleoptera: Bostrychidae) and Sitophilus oryzae (Coleoptera: Curculionidae)
Authors: Daglish Gregory J
Published: April 2004

Degree of dominance of phosphine resistance was investigated in adults of Rhyzopertha dominica F and Sitophilus oryzae L. Efficacy of the grain fumigant phosphine depends on both concentration and exposure period, which raises the possibility that dominance levels vary with exposure period. New and published data were used to test this possibility in adults of R dominica and S oryzae fumigated for periods of up to 144 h. The concentrations required for control of homozygous resistant and susceptible strains and their F1 hybrids decreased with increasing exposure period. For both species the response lines for the homozygous resistant and susceptible strains and their F1 hybrids were parallel. Therefore, neither dominance level nor resistance factor was affected by exposure period. Resistance was incompletely recessive and the level of dominance, calculated at 50% mortality level, was −0.59 for R dominica and −0.65 for S oryzae. The resistant R dominica strain was 30.9 times more resistant than the susceptible strain, compared with 8.9 times for the resistant S oryzae strain. The results suggest that developing discriminating doses for detecting heterozygote adults of either species will be difficult. Copyright © 2004 Society of Chemical Industry
Interaction between amyloid β‐protein aggregates and membranes
Authors: Kakio Atsuko , Yano Yoshiaki , Takai Denshi , Kuroda Yukihiro , Matsumoto Osamu , Kozutsumi Yasunori , Matsuzaki Katsumi
Published: April 2004

The conversion of soluble, nontoxic amyloid β‐protein (Aβ) to aggregated, toxic Aβ rich in β‐sheet structures is considered to be the key step in the development of Alzheimer's disease. Therefore, extensive studies have been carried out on the mechanisms involved in Aβ aggregation and the characterization of Aβ aggregates formed in aqueous solutions mimicking biological fluids. On the other hand, several investigators pointed out that membranes play an important role in Aβ aggregation. However, it remains unclear whether Aβ aggregates formed in solution and membranes are identical and whether the former can bind to membranes. In this study, using a dye‐labeled Aβ‐(1–40) as well as native Aβ‐(1–40), the properties of Aβ aggregates formed in buffer and raft‐like membranes composed of monosialoganglioside GM1/cholesterol/sphingomyelin were compared. Fourier transform infrared spectroscopic measurements suggested that Aβ aggregates formed in buffer and in membranes have different β‐sheet structures. Fluorescence experiments revealed that Aβ aggregated in buffer did not show any affinity for membranes. Copyright © 2004 European Peptide Society and John Wiley & Sons, Ltd.
NMR studies of peptide T, an inhibitor of HIV infectivity, in an aqueous environment
Authors: De Dios Angel C. , Sears Devin N. , Tycko Robert
Published: April 2004

The synthetic octapeptide peptide T (ASTTTNYT) has been shown to interfere with binding of the HIV‐1 envelope glycoprotein gp120 to the chemokine receptor R5, thus preventing viral infection. This study investigated the degree of conformational order of two analogs of peptide T, one biologically active (D‐Ala peptide T amide) and one inactive (D‐Ala, D‐Tyr peptide T amide) using nuclear magnetic resonance (NMR) spectroscopy in an aqueous environment, both in solution and in the frozen solid state. Standard solution NMR techniques such as DQFCOSY, HMQC, ROESY and inversion recovery measurements have been utilized to characterize these peptides. Solid state NMR experiments were likewise employed to study the peptides in a frozen glycerol:water mixture. The NMR results indicate that the monomeric form of both peptide T analogs have considerable conformational heterogeneity. Solid state NMR studies indicate aggregation of D‐Ala peptide T, possibly into a β‐sheet structure, at concentrations higher than 10 mM. Copyright © 2004 European Peptide Society and John Wiley & Sons, Ltd.
Effects of the dipole moments behavior on a vibronic coupling model for the four‐wave mixing signal
Authors: Cusati T. , Paz J. L. , Hernández A. J.
Published: April 2004

In the present work, we have studied modifications in the transition and permanent dipole moments of states in a coupled basis (including vibronic coupling) due to variations in the transition dipole moment between the uncoupled states, m12, as a function of the parameter δ = $\tilde{\omega}$0/ω0 (relative aperture) of the potential‐energy curves of the states involved. Modifications in the slopes of the transition and permanent dipole moments of the coupled states and changes in the magnitude of maximal intensity of the four‐wave mixing (FWM) signal are observed due to variations in these parameters. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Theoretical investigation of the structures and properties of fluoromethyl peroxyl radicals
Authors: El‐Taher S. , El‐Azhary Adel A.
Published: April 2004

The equilibrium geometries, harmonic vibrational frequencies, charge distributions, spin density distributions, dipole moments, electron affinities (EAs), and CO bond dissociation energies (BDEs) of HO, CH3O, CH2FO, CHF2O, and CF3O peroxyl radicals have been calculated using ab initio molecular orbital theory and density functional theory (DFT) at the B3LYP level. The CH bond dissociation energies of the parent fluoromethanes have been calculated using the same levels of theory. Both the MP2(full) and B3LYP methods, using the 6‐31G(d,p) basis set, are found to be capable of accurately predicting the geometries of peroxyl radicals. Electron correlation accounts for ∼25% of the CH BDE of fluoromethanes and for ∼50% of the CO BDE of the corresponding peroxyl radicals. The B3LYP/6‐31G(d,p) method is found to be comparable to high ab initio levels in predicting CO BDEs of studied peroxyl radicals and CH BDEs of the parent alkanes. The progressive fluorine substitution of hydrogen atoms in methyl peroxyl radicals results in shortening of the CO bond, lengthening of the OO bond, an increase (decrease) of the spin density on the terminal (inner) oxygen, a decrease in the dipole moments, and an increase in electron affinities. Both CO BDEs and EAs of peroxyl radicals (RO) correlate well with Taft σ* substituent constants for the R group in peroxyl radicals. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Emotion metaphors and emotional labor in science teaching
Authors: Zembylas Michalinos
Published: April 2004

An understanding of the importance of metaphors and beliefs in the development of teachers' practical knowledge has already been explored in science education research. However, the significance of emotion metaphors and the consequences of emotional labor as part of being a science teacher have been little addressed. This study describes the findings from a 3‐year ethnographic case study of an elementary‐school teacher who participated in a research project investigating the role of teacher emotion in science teaching and student learning. This research demonstrates how the performance of emotional labor is an important aspect of reality in science teaching. The teacher in this study is willing to do the emotional labor that involves some suffering because the emotional rewards are gratifying. A perspective on emotion in science education may focus, at least in part, on the functions of emotion in creating inspiring emotional cultures in science teaching and learning. Recognizing that teachers and students are agents in constructing such cultures, educators, teachers, and administrators are more likely to grasp the complexities and possibilities of emotional labor in the context of science education. © 2004 Wiley Periodicals, Inc. Sci Ed 88:301–324, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/.sce10116
Inquiry in science education: International perspectives
Authors: Abd‐El‐Khalick Fouad , BouJaoude Saouma , Duschl Richard , Lederman Norman G. , Mamlok‐Naaman Rachel , Hofstein Avi , Niaz Mansoor , Treagust David , Tuan Hsiao‐lin
Published: April 2004

This paper set emerged from an international symposium that aimed to shed light on issues associated with the enactment of inquiry both as means (i.e., inquiry as an instructional approach) and as ends (i.e., inquiry as a learning outcome) in precollege science classrooms. The symposium contributors were charged with providing perspectives from their countries on the following major themes: (a) philosophical and practical conceptions of inquiry in the science curriculum; (b) images of the enactment of inquiry in the curriculum, curricular materials, classroom instruction, and assessment practices; and (c) factors and conditions, internal and external to the educational setting, which facilitate or impede inquiry‐based science education. Another major theme that emerged from the symposium was related to the very conceptions of inquiry teaching. The individual contributions and synthesizing commentaries demonstrate that despite their situatedness and diversity, many themes and issues cut across the represented locales, and serve to show the significance and potential fruitfulness of any discourse regarding inquiry in science education that this paper set might, and we hope will, trigger in the near future. © 2003 Wiley Periodicals, Inc. Sci Ed 88:397–419, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/sce.10118
Exploring visuospatial thinking in chemistry learning
Authors: Wu Hsin‐Kai , Shah Priti
Published: April 2004

In this article, we examine the role of visuospatial cognition in chemistry learning. We review three related kinds of literature: correlational studies of spatial abilities and chemistry learning, students' conceptual errors and difficulties understanding visual representations, and visualization tools that have been designed to help overcome these limitations. On the basis of our review, we conclude that visuospatial abilities and more general reasoning skills are relevant to chemistry learning, some of students' conceptual errors in chemistry are due to difficulties in operating on the internal and external visuospatial representations, and some visualization tools have been effective in helping students overcome the kinds of conceptual errors that may arise through difficulties in using visuospatial representations. To help students understand chemistry concepts and develop representational skills through supporting their visuospatial thinking, we suggest five principles for designing chemistry visualization tools: (1) providing multiple representations and descriptions, (2) making linked referential connections visible, (3) presenting the dynamic and interactive nature of chemistry, (4) promoting the transformation between 2D and 3D, and (5) reducing cognitive load by making information explicit and integrating information for students. © 2004 Wiley Periodicals, Inc. Sci Ed 88:465–492, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/.sce10126
The practical epistemologies of the classroom: A study of laboratory work
Authors: Wickman Per‐Olof
Published: April 2004

The practical epistemologies of university students during laboratory work in chemistry are analyzed to enhance understanding of how teaching practices interact with learners. The purpose is to develop a theoretical framework of learning as action that can be used by educational researchers to examine meaning‐making, but also by teachers in close association with their daily work to understand the course learning takes in their own classrooms. Here this framework is adopted to demonstrate how the sequence of learning may affect the subject content learnt. It is also demonstrated how learning can be understood in terms of habits, and how observations of such habits could be used by a teacher to inform her/his teaching. The theory of practical epistemologies is based on the later Wittgenstein, pragmatics, and sociocultural approaches identifying learning with talk, action, and habits situated in practices. © 2004 Wiley Periodicals, Inc. Sci Ed 88:325–344, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/.sce10129
Explanation‐driven inquiry: Integrating conceptual and epistemic scaffolds for scientific inquiry
Authors: Sandoval William A. , Reiser Brian J.
Published: April 2004

Science education reforms consistently maintain the goal that students develop an understanding of the nature of science, including both the nature of scientific knowledge and methods for making it. This paper articulates a framework for scaffolding epistemic aspects of inquiry that can help students understand inquiry processes in relation to the kinds of knowledge such processes can produce. This framework underlies the design of a technology‐supported inquiry curriculum for evolution and natural selection that focuses students on constructing and evaluating scientific explanations for natural phenomena. The design has been refined through cycles of implementation, analysis, and revision that have documented the epistemic practices students engage in during inquiry, indicate ways in which designed tools support students' work, and suggest necessary additional social scaffolds. These findings suggest that epistemic tools can play a unique role in supporting students' inquiry, and a fruitful means for studying students' scientific epistemologies. © 2004 Wiley Periodicals, Inc. Sci Ed 88:345–372, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/.sce10130
Improving heuristic function of cost‐based abduction system using real‐time heuristic search
Authors: Koshino Makoto , Okamine Tadashi , Kimura Haruhiko , Hirose Sadaki
Published: April 2004

Cost‐based abduction, which can find a best explanation for a given observation by assuming some hypothesis, is an important framework of inference because it is applied to diagnosis, design, planning, natural language understanding, and so on. However, slow reasoning speed is a crucial drawback. In order to overcome this problem, previous work achieved an efficient system, and a search control technique of A* search was introduced into cost‐based abduction. However, the system has the problem that space complexity is very large because it has to store all of the many nodes. In this paper, we introduced real‐time heuristic search by which the user can set up look‐ahead depth and store only the best node. We also introduced a new heuristic function in order to inference successfully and speed up inconsistency processing. We examined the validity of our proposed method with a diagnostic problem of a logic circuit. © 2004 Wiley Periodicals, Inc. Syst Comp Jpn, 35(6): 89–97, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10254
LiveWatch: The interactive live casting system
Authors: Tanaka Kiyoshi , Taura Takahisa , Akutsu Akihito , Jinzenji Hiroshi , Tonomura Yoshinobu
Published: April 2004

This paper proposes a viewer support service in which user‐initiative value is added to livecasting programs, including livecasting with real‐time properties such as sportscasting. For example, a viewer support service in which the desired scene is provided on the basis of user settings is realized by using live information, consisting of the scene descriptions in livecasting, corresponding to the meta‐data of the video. In the LiveWatch system, the live information is input quickly and precisely by a manual procedure using an input support tool. The user application service is realized by aligning the video distribution to the live information, which involves delaying the distribution slightly. User applications, which differ for each type of casting and service, can be constructed in a simple way by using a newly developed authoring system. This paper describes the architecture of the LiveWatch system and reports the results of testing of a notification service using LiveWatch in an Internet netcasting experiment. © 2004 Wiley Periodicals, Inc. Syst Comp Jpn, 35(6): 31–41, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10595
Constructing a system for finger‐position determination and tablature generation for playing melodies on guitars
Authors: Miura Masanobu , Hirota Isao , Hama Nobuhiko , Yanagida Masazo
Published: April 2004

This paper describes the determination of optimal finger position for guitar performance for melodies. In general, when performing a given melody with a guitar, several finger positions are possible, and when beginners are playing, often it is difficult to determine a fingering position. In this paper, the authors propose a method to determine finger positions that minimize the burden on performance and remove a burden on novice guitar players, and then describe “S2T,” a system which outputs these results as tablature. The authors then confirm based on the results of a performance evaluation of S2T that it requires less burden than commercially available systems. © 2004 Wiley Periodicals, Inc. Syst Comp Jpn, 35(6): 10–19, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10609
Evaluation of salivary cortisol as a biomarker of self‐reported mental stress in field studies
Authors: Hjortskov Nis , Garde Anne Helene , Ørbæk Palle , Hansen Åse Marie
Published: April 2004

This study examines the association between self‐reported mental stress and the salivary cortisol response via a systematic literature review by using recommendations from the Cochrane Collaboration. Literature in different databases was screened and articles were selected on the basis of a set of inclusion criteria. Each article was assigned a total score on the basis of a rating system including objective and design of the studies, description of possible confounders, sampling strategy, description of psychosocial factors, and statistical analysis. The findings of the studies were considered to be inconsistent if less than 75 per cent of the high and medium quality studies reported the same conclusion. The literature search revealed a total of 73 studies. According to the inclusion criteria 14 field studies were selected for further evaluation. According to the rating system, seven studies were considered to be of high quality and seven studies of medium quality. No studies were considered to be of low quality. Four studies reported a positive association; two studies reported negative association and eight reported no association between self‐reported mental stress and the cortisol response. Accordingly, the evaluation of the studies in this paper showed insufficient evidence for an association between self‐reported mental stress and the cortisol response in field studies. Possibly the large diversity in study designs, the types and measures of mental stress, and the various salivary cortisol sampling strategies obscure any potential relationship. Copyright © 2004 John Wiley & Sons, Ltd.
Validation of a single‐item measure of burnout against the Maslach Burnout Inventory among physicians
Authors: Rohland Barbara M. , Kruse Gina R. , Rohrer James E.
Published: April 2004

The measurement of burnout among physicians is important because physician well‐being has the potential to affect workforce stability and quality of care. In this study, a single‐item measure of burnout was validated against the sub‐scales of the Maslach Burnout Inventory (emotional exhaustion, depersonalization, and personal accomplishment). Survey items included the 22‐item Maslach Burnout Inventory, a single‐item measure of burnout, and other questions regarding demographics, practice characteristics, and occupational satisfaction. The surveys were mailed to Texas Tech University School of Medicine Alumni classes of 1980–1989. The response rate was 43 per cent (n = 307). Pearson correlation coefficients and ANOVA were used to determine the association between the Maslach Burnout Inventory scores and the single‐item burnout question. The single‐item was correlated at r = 0.64 (p < 0.0001) with emotional exhaustion and the ANOVA yielded an R2 of 0.5 (p < 0.0001). Hence, in surveys of physicians where emotional exhaustion is the primary sub‐scale of interest, a single‐item measure of burnout may be used as an alternative to the Maslach Burnout Inventory in order to abbreviate survey material and potentially increase response rates among physicians. Copyright © 2004 John Wiley & Sons, Ltd.
Stress, symptoms of depression and anxiety, and cortisol patterns in working parents
Authors: Kurina Lianne M. , Schneider Barbara , Waite Linda J.
Published: April 2004

Whether stress or psychological distress is associated with alterations in diurnal cortisol secretion patterns in healthy adults is still uncertain. In this study, the authors tested for associations between stress or symptoms of depression or anxiety and changes in diurnal cortisol patterns in 91 working parents (57 women and 34 men) across the United States. Saliva samples were collected for cortisol analysis at six timepoints over 2 days. The diurnal cortisol slope and time‐weighted average cortisol levels were analysed in relation to (1) two survey measures of stress, (2) diary reports of stress during cortisol sampling, and (3) self‐reported depression and anxiety. Cortisol slopes and average cortisol levels varied widely across individuals and within individuals across days. Only two of the 24 associations between stress or psychological symptoms and cortisol were significant at the p < 0.05 level; men with more severe symptoms of anxiety had significantly higher average cortisol levels and women who reported that work was more frequently stressful had significantly lower average cortisol levels. These results highlight the variability of diurnal cortisol secretion patterns in healthy adults and suggest that neither stress nor psychological symptomatology is a strong determinant of differences in diurnal cortisol patterns in healthy individuals. Copyright © 2004 John Wiley & Sons, Ltd.
The flooding of Hat Yai: predictors of adverse emotional responses to a natural disaster
Authors: Assanangkornchai Sawitri , Tangboonngam Sa‐nguansri , Edwards J. Guy
Published: April 2004

Background: A severe flood occurred in Hat Yai following a torrential downpour of rain in November 2000, killing at least 32 people, injuring about 1700, and causing severe damage to property. We have assessed the effect of this disaster on the mental health of the community and investigated predictors of adverse emotional responses.

Method: A cross‐sectional survey using a structured questionnaire was carried out and Thai versions of the General Health Questionnaire (GHQ) and Impact of Event Scale (IES) were administered. Data on 590 respondents residing in four areas of the city and its environs were obtained.

Results: Two hundred and thirty‐three (40 per cent) respondents had a positive GHQ score suggesting a mental health problem. There were significant associations between a positive GHQ and the subjects' perception of the severity of loss, the ability to collect possessions, and showing a ‘negative’ response to the flood. High IES scores were associated with indices of the severity of loss, lower socio‐economic status and minority religion.

Conclusions: Natural disasters, such as floods, have a major impact on the mental health of a community. The impact is related to the perception of severity and loss, and is greater in lower socio‐economic and minority religious sub‐groups. Copyright © 2004 John Wiley & Sons, Ltd.
Latinas: The new Latino majority in college
Authors: González Kenneth P. , Jovel Jennifer E. , Stoner Carla
Published: April 2004

The numbers of Latinas who attend college, stay in college, graduate, and attend graduate school escalated in the 1990s, surpassing gains made by any other underrepresented group of students in higher education. However, their achievements come at a personal cost, as the high‐achieving Latinas profiled in this chapter demonstrate.
Hispanic‐serving institutions through the eyes of students and administrators
Authors: Dayton Boualoy , Gonzalez‐Vasquez Nancy , Martinez Carla R. , Plum Caryn
Published: April 2004

Every year, more colleges and universities become Hispanic‐serving institutions. These institutions, whether public or private, two‐year or four‐year, find themselves in the position of serving high numbers of Latino students. They encounter opportunities for unique learning environments, access to special funding, and the potential to be instrumental in Latino educational attainment.
Practical considerations of critical race theory and Latino critical theory for Latino college students
Authors: Villalpando Octavio
Published: April 2004

Critical race theory requires the examination of institutional policies, programs, and practices that interfere with Latino students' rights and abilities to receive the best educational opportunities available within higher education. With attention to an ethic of caring and social justice, student services staff can work to undo the effects of racism on campus.
Creating meaning from intersections of career and cultural identity
Authors: Gross Linda S.
Published: April 2004

For Latino students, career development and planning includes the negotiation of family influences, peer expectations, and challenges as they develop career efficacy in work experiences as undergraduates. The model presented here outlines how students can benefit from a holistic perspective on the intersections of career and cultural identity.
Support programs that work
Authors: Mina Liliana , Cabrales José A. , Juarez Cynthia M. , Rodriguez‐Vasquez Fernando
Published: April 2004

Research shows that Latino students are grossly underrepresented in higher education. In this chapter, however, we show how family, community, and institutional partnerships can be an evidence‐based practice for faculty and student affairs professionals who wish to increase Latino participation and graduation rates.
Promoting the success of Latino students: A call to action
Authors: Ortiz Anna M.
Published: April 2004

This synthesis of the volume offers recommendations that will help student services personnel to facilitate the success of Latino students in higher education.
Sonographic demonstration of brain injury in fetuses with severe red blood cell alloimmunization undergoing intrauterine transfusions
Authors: Ghi T. , Brondelli L. , Simonazzi G. , Valeri B. , Santini D. , Sandri F. , Ancora G. , Pilu G.
Published: April 2004

Objective

To assess sonographically brain anatomy in fetuses with severe anemia due to red blood cell alloimmunization undergoing intrauterine intravascular transfusions.

Methods

Multiplanar neurosonography was performed in seven consecutive hydropic fetuses undergoing intrauterine transfusions (mean gestational age 22 ± 2.5 weeks; mean hemoglobin concentration at the first transfusion 2.3 ± 1.0 g/dL).

Results

Abnormal cerebral findings were identified in four out of seven fetuses. An intracerebellar hemorrhage developed in two fetuses after the first transfusion and one fetus that had severe brain edema before the first transfusion was later found to have cystic periventricular leukomalacia. In one fetus unilateral ventriculomegaly was noted after the first transfusion. Two fetuses were terminated. The remaining pregnancies had an uneventful course, the infants were delivered between 34 and 36 gestational weeks and were alive and well at the time of writing. Prenatal diagnosis of brain injury was always confirmed except for the case with ventriculomegaly that underwent spontaneous intrauterine resolution.

Conclusions

Fetuses with extreme anemia due to red blood cell alloimmunization can be salvaged by intrauterine transfusion. In some of these cases brain injury may occur prenatally, and the risk seems to be particularly high when the hemoglobin concentration at the time of the first transfusion is ≤ 2 g/dL. We suggest that in these pregnancies detailed fetal neuroimaging by either multiplanar sonography and/or magnetic resonance imaging is indicated. Copyright © 2004 ISUOG. Published by John Wiley & Sons, Ltd.
Tailored management of twin reversed arterial perfusion (TRAP) sequence
Authors: Weisz B. , Peltz R. , Chayen B. , Oren M. , Zalel Y. , Achiron R. , Lipitz S.
Published: April 2004

Objective

To describe our management of pregnancies complicated by twin reversed arterial perfusion (TRAP) sequence.

Methods

This was a retrospective study involving all cases of TRAP sequence referred to our fetal medicine unit in a 3‐year period (2000–2002). Patients were routinely managed by repeat sonographic surveillance with sonographic anatomical evaluation and detailed echocardiography. Cases with signs of impending cardiac failure were treated by in‐utero YAG‐laser coagulation of the umbilical vessels of the acardiac twin.

Results

Six cases were studied. Three patients in whom there were no signs of deterioration in the status of the pump twin, and in whom the acardiac twin was smaller than the pump twin, were managed conservatively. However, one of these with monoamniotic twins ended in intrauterine fetal death of the pump twin. The other two cases presented with spontaneous cessation of blood flow in the umbilical artery of the acardiac twin. Both delivered at term normal neonates whose follow‐up revealed no signs of neurological sequelae. One case of quadruplet pregnancy (with TRAP sequence and two dichorionic twins) was treated by selective termination of the monochorionic twins. Two cases with signs of impending cardiac failure were treated by in‐utero YAG‐laser occlusion of the vessels in the acardiac mass. Both interventions had a favorable outcome.

Conclusions

Conservative treatment is suitable for milder cases of TRAP sequence in which the pump twin is the larger one. Cases in which the acardiac twin is larger have a poorer prognosis and should be treated by invasive intervention and cord occlusion. Copyright © 2004 ISUOG. Published by John Wiley & Sons, Ltd.
On the autocorrelation and the triple correlation equation for complex‐valued signals
Authors: v. Wolfersdorf L.
Published: April 2004

The paper deals with the autocorrelation equation on a finite interval and on the half‐axis and with the triple correlation equation in the case of complex‐valued signals. Via methods of Fourier transformation the equations are reduced to boundary value and continuation problems for holomorphic functions in the upper half‐plane and to functional equations in two independent variables, respectively, and in this way solved in closed form. Thereby, on the one side, Cauchy integrals and Paley‐Wiener conditions and, on the other side, the solution of a known functional equation in a single variable are applied.
Global existence of solutions of the Dirichlet problem for the compressible Navier‐Stokes equations
Authors: Mucha P.B. , Zaja̧czkowski W.M.
Published: April 2004

We prove the existence of global in time regular solutions of the compressible Navier‐Stokes equations in a domain Ω ⊂ R3 with vanishing Dirichlet boundary conditions. The solutions are close to nontrivial static solutions. A key element of the proof is a special Lp‐estimate for the linearized problem to show that the velocity belongs to W2,1r(loc)(Ω × [0,∞)) with r > 3 which is the sharp result in this approach.
The existence of positive periodic solutions for periodic feedback control systems with delays
Authors: Fan G. , Li Y. , Qin M.
Published: April 2004

This paper considers periodic feedback control systems of differential equations with delays. Applying a continuation theorem, a criterion for the existence of a positive periodic solution is established.
Reynolds‐stress balance equations in orthogonal helical coordinates and application
Authors: Hüttl T.J. , Chaudhuri M. , Wagner C. , Friedrich R.
Published: April 2004

Recently, direct numerical simulations of turbulent flow in helically coiled pipes have been performed and published. Here, computational results are shown for low Reynolds number flow (Reτ = 230) through one helical pipe configuration (curvature κ R = 0.1, torsion τ R = 0.165). The results are shortly discussed and further information of other toroidal or helical pipe flow simulations are given. Besides, the Reynolds‐stress balance equations derived in orthogonal helical coordinates are presented to allow further insight into helical pipe flow. The Reynolds‐stress balance equations are of great importance for turbulence modelling. Compared to their formulation in cylindrical coordinates, further terms occur, describing centrifugal and other inertia force effects which result from pipe curvature and torsion. Except for toroidal flow, where torsion is zero and a symmetry plane exists, no possibility to simplify the equations has been found.
Modeling evidence for recent warming of the Arctic soil thermal regime
Authors: Oelke Christoph , Zhang Tingjun , Serreze Mark C.
Published: April 2004

Daily soil temperature and thaw depth for the entire Arctic terrestrial drainage area are simulated using a one‐dimensional heat transfer model with phase change. Analyses of temperature trends at the soil surface and at 2 m depth are presented for the 23‐year time period 1980 through 2002. Soil warming is simulated for all permafrost regions, but is most pronounced (0.044°C/yr) at the surface in the continuous permafrost region. Trends for most recent years (1994–2002) are about three times higher. Active layer depth increases significantly for parts of Alaska and northern Canada, and southern and eastern Siberia. As assessed for the major river drainages, the most dramatic active layer deepening occurs in the Yenisey basin.
Direct inversion of velocity interfaces
Authors: Zhou Hua‐Wei
Published: April 2004

Seismic tomography traditionally inverts for velocity field on a regularly spaced and fixed‐in‐space model grid. Such an approach is not able to adequately describe pinchouts or wedge‐shaped velocities as commonly seen at basin boundaries, faulted rock beds, and back‐arc mantle wedges. A regularly spaced model grid also requires the use of a large number of model variables. This paper shows a different approach called deformable layer tomography (DLT) to directly invert for velocity interfaces. The use of thickness‐varying layers allows a much smaller number of model variables for the DLT than the regularly spaced model grid. In the DLT the geologic framework and known velocity range are adopted into the initial reference model, and the best‐data‐fitting geometry of the velocity interfaces is determined, as illustrated by synthetic and field data examples.
Assessment of current passive‐microwave‐ and infrared‐based satellite rainfall remote sensing for flood prediction
Authors: Hossain Faisal , Anagnostou Emmanouil N.
Published: April 2004

The adequacy of current passive‐microwave‐(PM)‐ and infrared‐(IR)‐based satellite rainfall retrieval and sampling for flood prediction of a medium‐sized watershed is investigated. On the basis of Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar rainfall measurements, rain retrieval error parameters for PM and IR sensors are derived. PM rain retrievals are inferred from the overland component of the TRMM Microwave Imager (TMI) rain estimation algorithm, while IR retrievals are obtained from hourly PM‐calibrated IR rain fields, which are part of a variable rainfall product (VAR) array produced at NASA/GSFC. A probabilistic error model is developed for satellite‐based precipitation measurements on the basis of retrieval error parameters in this simulation study. The PM rain detection ability was found to be significantly more sensitive than that of IR while the successful no‐rain detection probabilities were found to be 93% and 88%, respectively. The IR retrieval was found to give false alarm rain rates about twice as large as that of PM. The PM sensor constellation comprised two Special Sensor Microwave Imagers (SSM/I) (F14 and F15), the TMI, and the Advanced Microwave Sensing Radiometer (AMSR‐E). It was found that current PM sampling is associated with flood prediction uncertainty approximately 50–100% higher than that of a canonical 3‐hourly sampling planned for the Global Precipitation Measurement (GPM) mission. The comparatively greater limitation in capturing the correct space‐time rain structure by IR retrievals had the effect of increasing the error in predicting the time of peak runoff when merging was performed with PM retrievals. It was found that a reduced standard error (<100%) in IR retrieval combined with a higher probability of rain detection (POD) (>0.90) can make IR retrievals useful in reducing uncertainty in the prediction of peak runoff. To reduce the error in time to peak, further improvement, such as reduction in the IR retrieval's false alarm rates coupled with an even higher POD, may be necessary. In terms of overall runoff volume, combined moderate improvements in POD and error variance of current IR retrieval algorithms are sufficient for the reduction of prediction uncertainty.
Radiation balance of the tropical tropopause layer
Authors: Gettelman Andrew , Forster Piers M. de F. , Fujiwara Masatomo , Fu Qiang , Vömel Holger , Gohar Laila K. , Johanson Celeste , Ammerman Marie
Published: April 2004

The radiation balance of the tropical tropopause layer (TTL) is examined using several different radiation codes with standard profiles compiled from observations in the tropics assuming clear sky conditions. These codes include detailed radiative transfer models and simplified codes for global climate models. The importance of the various radiatively active gases are examined. Water vapor is the most important contributor to the TTL radiation balance, but carbon dioxide and ozone also play a role. Differences in radiative heating between radiation models are mostly due to treatments of shortwave radiation. Differences between models below the TTL are due to different treatments of water vapor continuum absorption. The level of zero clear sky radiative heating, a level important for understanding the transport of air into the stratosphere, is generally found near 15 km, 125 hPa and 200°K (360 K potential temperature), consistent with previous work. Changes in time and space can modify this level by ±500 m, and individual profiles vary from these averages by ±400 m (1σ). Increases in water vapor in the TTL would tend to increase the altitude of the level at which the net heating is zero, while increases in carbon dioxide or ozone would tend to decrease this level. Clouds in the TTL tend to increase the level due to enhancements in longwave cooling above clouds. The implications for transport are discussed.
Observations of total alkyl nitrates during Texas Air Quality Study 2000: Implications for O3 and alkyl nitrate photochemistry
Authors: Rosen R. S. , Wood E. C. , Wooldridge P. J. , Thornton J. A. , Day D. A. , Kuster W. , Williams E. J. , Jobson B. T. , Cohen R. C.
Published: April 2004

Observations of total alkyl nitrates (ΣANs) were obtained using thermal dissociation‐laser‐induced fluorescence at La Porte, Texas, from 15 August to 15 September 2000, along with an extensive suite of other nitrogen oxides, hydrocarbons, and O3. The ΣAN mixing ratios ranged as high as 5.2 ppbv. The median midday mixing ratio was 1.2 ppbv, and the median nighttime mixing ratio was 0.26 ppbv. These are higher mixing ratios than the sum of individual nitrates in virtually every prior study. The diurnal variation of ΣANs was similar to that of HNO3 and of total peroxy nitrates, with a peak near 1300 local time (LT) indicating a photochemical source. Mixing ratios decreased rapidly in the afternoon, suggesting that ΣAN deposition is nearly as fast as HNO3 deposition. The observed correlation between O3 and ΣANs has a slope that increases from 29 (R2 = 0.73) ΔOx/ΔΣANs at 0900–1200 LT to 41 (R2 = 0.74) ΔOx/ΔΣANs at 1400–1800 LT. We present calculations constrained by the observed hydrocarbons showing that both the mixing ratio of ΣANs and the correlation of ΣANs with O3 are to be expected on the basis of the branching ratios for alkyl nitrate formation in the RO2 + NO reaction.