bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of hospital length of stay and discharge destination using hazard functions with unmeasured heterogeneity
Authors: Picone Gabriel , Mark Wilson R. , Chou Shin‐Yi
Published: December 2003

The hospital length‐of‐stay and the discharge destination of a Medicare patient are the outcomes of one decision process involving the interests of the patient, the hospital, and the firms offering covered post‐hospital care. We use a competing risk hazard estimation procedure and adjust for unobserved heterogeneity with a non‐parametric technique to identify significant factors in the decision process. A patient's health and socio‐economic characteristics, the availability of informal care, local market area conditions, and Medicare policies influence length‐of‐stay and discharge destination. The substitution we find between hospital and post‐hospital care and among post‐hospital care alternatives has policy implications for Medicare. Copyright © 2003 John Wiley & Sons, Ltd.
An evaluation of sediment rating curves for estimating suspended sediment concentrations for subsequent flux calculations
Authors: Horowitz Arthur J.
Published: December 2003

In the absence of actual suspended sediment concentration (SSC) measurements, hydrologists have used sediment rating (sediment transport) curves to estimate (predict) SSCs for subsequent flux calculations. Various evaluations of the sediment rating‐curve method were made using data from long‐term, daily sediment‐measuring sites within large (>1 000 000 km2), medium (<1 000 000 to >1000 km2), and small (<1000 km2) river basins in the USA and Europe relative to the estimation of suspended sediment fluxes. The evaluations address such issues as the accuracy of flux estimations for various levels of temporal resolution as well as the impact of sampling frequency on the magnitude of flux estimation errors.

The sediment rating‐curve method tends to underpredict high, and overpredict low SSCs. As such, the range of errors associated with concomitant flux estimates for relatively short time‐frames (e.g. daily, weekly) are likely to be substantially larger than those associated with longer time‐frames (e.g. quarterly, annually) because the over‐ and underpredictions do not have sufficient time to balance each other. Hence, when error limits must be kept under ±20%, temporal resolution probably should be limited to quarterly or greater.

The evaluations indicate that over periods of 20 or more years, errors of <1% can be achieved using a single sediment rating curve based on data spanning the entire period. However, somewhat better estimates for the entire period, and markedly better annual estimates within the period, can be obtained if individual annual sediment rating curves are used instead. Relatively accurate (errors <±20%) annual suspended sediment fluxes can be obtained from hydrologically based monthly measurements/samples. For 5‐year periods or longer, similar results can be obtained from measurements/samples collected once every 2 months. In either case, hydrologically based sampling, as opposed to calendar‐based sampling is likely to limit the magnitude of flux estimation errors. Published in 2003 John Wiley & Sons, Ltd.
Simulating methane emission from a Chinese rice field as influenced by fertilizer and water level
Authors: Yu Z. , Shangguan X. , Pollard D. , Barron E. J.
Published: December 2003

Natural and agricultural wetlands are considered to be the major sources of global atmospheric methane (CH4). A one‐dimensional model was developed to simulate methane emission and used to examine the influence of various physical processes on the rate of methane emission. Three processes involved in the methane emission are implemented in the model: production, reoxidation and transport. Three transport pathways were considered: diffusion across water–air or soil–air interfaces, ebullition and diffusion through plants. These pathways are influenced by soil properties, plant growth, water‐table conditions, temperature and external inputs (e.g. fertilizer). The model was used to examine the seasonal variation of the methane emission at a rice field in Hunan, China, which was observed during a field experiment for consecutive (early and late) rice seasons in 1992. The observed seasonal variations of methane emission, and role of plants in transporting methane to the atmosphere, are captured by the model simulation. Further model applications were conducted to simulate effects of fertilizer and water‐level condition on the methane emission. The results indicate that unfermented organic fertilizer produces a higher methane emission rate than mineral fertilizer. The simulations with treatments of a deep‐water covering and constant moisture reduced the methane emission. The rice field study provides a framework for further development of the model towards simulations based on spatially distributed variables (e.g. water table, soil temperature and vegetation) at a regional scale. Copyright © 2003 John Wiley & Sons, Ltd.
Estimation of snow water equivalent using microwave radiometry over Arctic first‐year sea ice
Authors: Barber D. G. , Iacozza J. , Walker A. E.
Published: December 2003

The magnitude and spatial distribution of snow on sea ice are both integral components of the ocean–sea‐ice–atmosphere system. Although there exists a number of algorithms to estimate the snow water equivalent (SWE) on terrestrial surfaces, to date there is no precise method to estimate SWE on sea ice. Physical snow properties and in situ microwave radiometry at 19, 37 and 85 GHz, V and H polarization were collected for a 10‐day period over 20 first‐year sea ice sites.

We present and compare the in situ physical, electrical and microwave emission properties of snow over smooth Arctic first‐year sea ice for 19 of the 20 sites sampled. Physical processes creating the observed vertical patterns in the physical and electrical properties are discussed. An algorithm is then developed from the relationship between the SWE and the brightness temperature measured at 37 GHz (55°) H polarization and the air temperature. The multiple regression between these variables is able to account for over 90% of the variability in the measured SWE. This algorithm is validated with a small in situ data set collected during the 1999 field experiment. We then compare our data against the NASA snow thickness algorithm, designed as part of the NASA Earth Enterprise Program. The results indicated a lack of agreement between the NASA algorithm and the algorithm developed here. This lack of agreement is attributed to differences in scale between the Special Sensor Microwave/Imager and surface radiometers and to differences in the Antarctic versus Arctic snow physical and electrical properties. Copyright © 2003 John Wiley & Sons, Ltd.
Ice‐cover variability on shallow lakes at high latitudes: model simulations and observations
Authors: Duguay Claude R. , Flato Greg M. , Jeffries Martin O. , Ménard Patrick , Morris Kim , Rouse Wayne R.
Published: December 2003

A one‐dimensional thermodynamic model for simulating lake‐ice phenology is presented and evaluated. The model can be driven with observed daily or hourly atmospheric forcing of air temperature, relative humidity, wind speed, cloud amount and snowfall. In addition to computing the energy balance components, key model output includes the temperature profile at an arbitrary number of levels within the ice/snow (or the water temperature if there is no ice) and ice thickness (clear ice and snow‐ice) on a daily basis, as well as freeze‐up and break‐up dates. The lake‐ice model is used to simulate ice‐growth processes on shallow lakes in arctic, sub‐arctic, and high‐boreal forest environments. Model output is compared with field and remote sensing observations gathered over several ice seasons. Simulated ice thickness, including snow‐ice formation, compares favourably with field measurements. Ice‐on and ice‐off dates are also well simulated when compared with field and satellite observations, with a mean absolute difference of 2 days. Model simulations and observations illustrate the key role that snow cover plays on the seasonal evolution of ice thickness and the timing of spring break‐up. It is also shown that lake morphometry, depth in particular, is a determinant of ice‐off dates for shallow lakes at high latitudes. Copyright © 2003 John Wiley & Sons, Ltd.
Influences on HIV testing among young African‐American men who have sex with men and the moderating effect of the geographic setting
Authors: Mashburn Andrew J. , Peterson John L. , Bakeman Roger , Miller Robin L. , Clark Leslie F.
Published: December 2003

This study examined the influence of demographic characteristics, risk behaviors, knowledge, and psychosocial variables on HIV testing among a sample (n = 551) of young African‐American men who have sex with men (MSM) from three cities—Atlanta (n = 241), Birmingham (n = 174), and Chicago (n = 136). Among the entire sample of young men, age, knowledge of HIV treatments, knowledge of a comfortable place for an HIV test, and social support were related positively to rates of HIV testing. Furthermore, men who had sex with both main male partner(s) and non‐main male partner(s) during the past year had significantly higher rates of HIV testing than men who had non‐main male partner(s) only. Geographic setting moderated the effect on HIV testing behavior. In particular, social support, peer norms about condom use, and knowledge of HIV treatments were not associated with HIV testing in Atlanta, but were associated positively with HIV testing in either Birmingham, Chicago, or both. The strongest influence on HIV testing across all three settings was knowledge of a comfortable place for an HIV test. Implications of these findings for designing interventions to increase HIV testing are discussed. © 2004 Wiley Periodicals, Inc. J Comm Psychol 32: 45–60, 2004.
Building resilience for uncertain times
Authors: Stoltz Paul G.
Published: December 2003

Strengthening resilience expands your speed and capacity for meeting life's demands.
The leader's role in managing conflict
Authors: Guttman Howard M.
Published: December 2003

How leaders can serve as role models in managing conflict.
Health‐related quality of life in patients with progressive supranuclear palsy
Authors: Schrag Anette , Selai Caroline , Davis Jennifer , Lees Andrew J. , Jahanshahi Marjan , Quinn Niall
Published: December 2003

We assessed health‐related quality of life (QoL) of patients with progressive supranuclear palsy (PSP), identified the most important QoL issues in patients with this disorder, and assessed the usefulness of existing QoL measures in patients with PSP. Twenty‐seven patients in all stages of PSP and their carers underwent a semistructured in‐depth interview on the impact of PSP and a neurological examination. They were also asked to complete existing measures of QoL and depression. An item‐pool of issues relevant to QoL of patients with PSP was created from the patient and carer interviews. Carers and patients largely agreed on issues relevant for patients' QoL but more carers than patients considered symptoms of frontal lobe dysfunction as problematic for the patients. There was no association of QoL with age and gender, as assessed in interviews and on two QoL instruments. QoL deteriorated with increasing disease duration and severity and greater cognitive impairment and was associated with worse depression scores. While the generic SF‐36 was not found to be useful to assess QoL in PSP, feasibility and validity for the PDQ‐39 and the EQ‐5D were acceptable in this study. However, additional issues relevant to patients with PSP that were not addressed in these instruments included visual disturbances, dysarthria, dysphagia, muddled thinking, confusion, and apathy. The generic EQ‐5D and the Parkinson's disease‐specific PDQ‐39 are useful instruments to assess QoL in patients with PSP. However, they lack questions on important aspects of QoL in PSP that were reported by patients and carers in semistructured interviews. The item pool created in these interviews provides the basis for the development of disease‐specific QoL instruments for patients with PSP. © 2003 Movement Disorder Society
Sweating dysfunction in Parkinson's disease
Authors: Swinn Lesley , Schrag Anette , Viswanathan Ramchandran , Bloem Bastiaan R. , Lees Andrew , Quinn Niall
Published: December 2003

We sought to determine the prevalence and nature of sweating disturbances in patients with Parkinson's disease (PD), and investigated their correlation with other clinical features and with Quality of Life (QoL) measures. A questionnaire on symptoms and consequences of sweating dysfunction was completed by 77 consecutive outpatients, from three movement disorder clinics, and 40 controls. QoL was assessed using the disease‐specific Parkinson's Disease Questionnaire (PDQ)‐39 and generic EuroQoL (EQ)‐5D rating scales. Patients also underwent a clinical examination, including assessment with the Unified Parkinson's Disease Rating Scale and the Hoehn and Yahr staging system. Sweating disturbances, either hypohidrosis or in particular, hyperhidrosis, were reported by 64% of patients and by 12.5% of controls (P < 0.005) and were often localised or asymmetric. Complaints of sweating disturbances were not correlated with disease severity, but did correlate with other symptoms of autonomic dysfunction. Sweating problems occurred predominantly in off periods and in on periods with dyskinesias. Sweating disturbances were not correlated with overall QoL scores, but we did observe a significant correlation with the pain dimension of the PDQ‐39 and the visual analogue scale of the EQ‐5D. Furthermore, many patients reported physical, social, and emotional impairment due to sweating. Sweating disturbances are common and distressing symptoms of PD that are related mainly to autonomic dysfunction, off periods, and dyskinesias. © 2003 Movement Disorder Society
Embryonic mesencephalic grafts increase levodopa‐induced forelimb hyperkinesia in parkinsonian rats
Authors: Steece‐Collier Kathy , Collier Timothy J. , Danielson Paul D. , Kurlan Roger , Yurek David M. , Sladek John R.
Published: December 2003

Recent observations from clinical trials of neural grafting for Parkinson's disease (PD) have demonstrated that grafted dopamine neurons can worsen dyskinesias in some graft recipients. This deleterious side effect reveals a new challenge for neural transplantation, that of elucidating mechanisms underlying these postgraft dyskinesias. One problem facing this challenge is the availability of a cost‐effective and reliable animal model in which to pursue initial investigations. In the current study, we investigated the interaction of an embryonic ventral mesencephalic (VM) dopamine (DA) neuron graft on levodopa (LD)‐induced dyskinetic movements in unilaterally 6‐hydroxydopamine‐lesioned rats. Rats were administered LD (levodopa‐carbidopa, 50:5 mg/kg) twice daily for 6 weeks after either a sham graft or VM DA graft. Although a single solid graft of embryonic DA neurons can prevent progression of some lesioned‐induced behavioral abnormalities such as LD‐induced rotation and dystonia, it significantly increases hyperkinetic movements of the contralateral forelimb. This differential effect of grafted neurons on abnormal behavioral profiles is reminiscent of that reported in grafted patients with PD. Data from this study illustrate important similarities between this model of parkinsonism and PD in human patients that make it suitable for initial preclinical investigations into possible mechanisms underlying postgraft aggravation of dyskinetic movements. © 2003 Movement Disorder Society
Standardized training tools for the UPDRS activities of daily living scale: Newly available teaching program
Authors: Goetz Christopher G. , LeWitt Peter A. , Weidenman Meredith
Published: December 2003

The Unified Parkinson's Disease Rating Scale (UPDRS) is the most widely used scale for evaluation of clinical impairment in PD. Whereas the motor section has been studied intensively for clinimetric properties and has an associated training tape, the Activities of Daily Living (ADL) section has been studied less rigorously. In preparation for a multicenter study that planned to use the UPDRS ADL score as an outcome, the authors reviewed the UPDRS ADL scale and designed a teaching program to provide a uniform technique for data acquisition without changing any wording of the primary scale. The teaching program is composed of four components: overall guidelines, clarifying points, recommended strategies, and a teaching videotape. The videotape shows examples of interviewers assessing each ADL item with patients of different disability levels and provides a complete ADL assessment of a single patient. Systematic training and utilization of this teaching program offer the potential for more uniformity in results of ADL assessments conducted in clinical practice and multicenter, international studies of PD. The written materials and videotape belong to the Movement Disorder Society and are available by contacting the MDS central office. © 2003 Movement Disorder Society
Role of dopamine transporter imaging in routine clinical practice
Authors: Marshall Vicky , Grosset Donald
Published: December 2003

Functional imaging of the dopamine transporter (DAT) defines integrity of the dopaminergic system and has its main clinical application in patients with mild, incomplete, or uncertain parkinsonism. Imaging with specific single positron emission computerised tomography ligands for DAT (FP‐CIT, β‐CIT, IPT, TRODAT) provides a marker for presynaptic neuronal degeneration. Striatal uptake correlates with disease severity, in particular bradykinesia and rigidity, and monitoring of progression assists in clinical trials of potential neuroprotective drugs. DAT imaging is abnormal in idiopathic Parkinson's disease, multiple system atrophy and progressive supranuclear palsy and does not distinguish between these disorders. Dopamine loss is seen even in the earliest clinical presentations of true parkinsonism; a normal scan suggests an alternative diagnosis such as essential tremor, vascular parkinsonism (unless there is focal basal ganglia infarction), drug‐induced parkinsonism, or psychogenic parkinsonism. Congruence between working clinical diagnosis and DAT imaging increases over time in favour of baseline DAT imaging results. Additional applications are characterising dementia with parkinsonian features (abnormal results in dementia with Lewy bodies, normal in Alzheimer's disease); and differentiating juvenile‐onset Parkinson's disease (abnormal DAT) from dopa‐responsive dystonia (normal DAT). © 2003 Movement Disorder Society
Deep brain stimulation for Parkinson's disease dissociates mood and motor circuits: A functional MRI case study
Authors: Stefurak Taresa , Mikulis David , Mayberg Helen , Lang Anthony E. , Hevenor Stephanie , Pahapill Peter , Saint‐Cyr Jean , Lozano Andres
Published: December 2003

Behavioral disturbances have been reported with subthalamic (STN) deep brain stimulation (DBS) treatment in Parkinson's disease (PD). We report correlative functional imaging (fMRI) of mood and motor responses induced by successive right and left DBS. A 36‐year‐old woman with medically refractory PD and a history of clinically remitted depression underwent uncomplicated implantation of bilateral STN DBS. High‐frequency stimulation of the left electrode improved motor symptoms. Unexpectedly, right DBS alone elicited several reproducible episodes of acute depressive dysphoria. Structural and functional magnetic resonance imaging (fMRI) imaging was carried out with sequential individual electrode stimulation. The electrode on the left was within the inferior STN, whereas the right electrode was marginally superior and lateral to the intended STN target within the Fields of Forel/zona incerta. fMRI image analysis (Analysis of Functional NeuroImages, AFNI) contrasting OFF versus ON stimulation identified significant lateralized blood oxygen level‐dependent (BOLD) signal changes with DBS (P < 0.001). Left DBS primarily showed changes in motor regions: increases in premotor and motor cortex, ventrolateral thalamus, putamen, and cerebellum as well as decreases in sensorimotor/supplementary motor cortex. Right DBS showed similar but less extensive change in motor regions. More prominent were the unique increases in superior prefrontal cortex, anterior cingulate (Brodmann's area [BA] 24), anterior thalamus, caudate, and brainstem, and marked widespread decreases in medial prefrontal cortex (BA 9/10). The mood disturbance resolved spontaneously in 4 weeks despite identical stimulation parameters. Transient depressive mood induced by subcortical DBS stimulation was correlated with changes in mesolimbic cortical structures. This case provides new evidence supporting cortical segregation of motor and nonmotor cortico‐basal ganglionic systems that may converge in close proximity at the level of the STN and the adjacent white matter tracts (Fields of Forel/zona incerta). © 2003 Movement Disorder Society
Posttraumatic painful torticollis
Authors: Sa Daniel S. , Mailis‐Gagnon Angela , Nicholson Keith , Lang Anthony E.
Published: December 2003

The development of abnormal posturing of the neck or shoulder after local injury has been termed posttraumatic cervical dystonia (PTCD). Certain features seem to distinguish a unique subgroup of patients with this disorder from those with features more akin to typical idiopathic cervical dystonia, such as onset and maximum disability that occurs very quickly after injury, severe pain and a fixed abnormal posture. In an attempt to clarify the nature of this syndrome further, we evaluated 16 such patients (8 men, 8 women). Motor vehicle accident and work‐related injuries were common precipitants, with posturing usually developing shortly after trauma, and little progression occurring after the first week. A characteristic, painful, fixed head tilt and shoulder elevation were present in all but one patient, who had a painless elevated shoulder and painful contralateral shoulder depression, as well as nondermatomal sensory loss in 14 patients. Additional abnormalities included dystonic posturing in a limb (2 patients) or jaw (1 patient), limb tremor (3 patients) and “give‐way” limb weakness (8 patients). The tremor and the jaw dystonia demonstrated features suggestive of a psychogenic movement disorder, most commonly distractibility. Litigation or compensation was present in all 16 patients. Intravenous sodium amytal improved the posture, pain or both in 13 of 13 patients; in 7 of 13 the sensory deficit either markedly improved or normalized. General anesthesia demonstrated full range of motion in all 5 patients assessed. Psychological evaluations suggested that psychological conflict, stress, or both were being expressed via somatic channels in 11 of 12 tested patients. Our results suggest an important role of psychological factors in the etiology or maintenance of abnormal posture, pain and associated disability of these patients. The role of central factors triggered in psychologically vulnerable individuals after physical trauma is discussed. We propose that the disorder be referred to as “posttraumatic painful torticollis” rather than characterize it as a form of dystonia until further information on its pathogenesis is forthcoming. © 2003 Movement Disorder Society
Paroxysmal exercise‐induced dystonia as a presenting feature of young‐onset Parkinson's disease
Authors: Bozi Maria , Bhatia Kailash P.
Published: December 2003

Paroxysmal exercise‐induced dystonia (PED) is a rare, typically idiopathic familial condition, although sporadic and secondary cases have been reported. We present 2 cases where PED was the presenting feature of young‐onset idiopathic Parkinson's disease (PD), preceding the onset of parkinsonian symptoms by 1.5 and 5 years, respectively. Initially, the dystonic symptoms occurred after prolonged exercise and were unilateral, affecting the foot in both patients. Over time, symptoms occurred with minimal exercise. We conclude that PED can rarely be the first and only feature of PD. © 2003 Movement Disorder Society
Dystonia in AIDS: Report of four cases
Authors: Factor Stewart A. , Troche‐Panetto Michelle , Weaver Susan A.
Published: December 2003

Dystonia is a rare complication of acquired immune deficiency syndrome (AIDS). We report four such cases related to three different causes. Cases 1 and 2 both developed dystonia secondary to biopsy‐proven progressive multifocal leukoencephalopathy. One had left arm dystonia, whereas the other had bilateral upper limb dystonia. One patient had associated akinesia and rigidity. Imaging demonstrated frontal and/or parietal white matter lesions but no basal ganglia abnormalities. Case 3 developed hemidystonia and cervical dystonia from biopsy‐proven toxoplasmosis with a lesion in the thalamus. Case 4 suffered from AIDS dementia complex and developed cervical dystonia while taking risperidone therapy. We also review previously reported cases of dystonia in AIDS patients with the same causes and discuss the issue of increased vulnerability of the basal ganglia to HIV infection which, in turn, leads to increased sensitivity to neuroleptics. When dystonia is seen in AIDS patients, its pattern may be a clue to the ultimate cause. © 2003 Movement Disorder Society
Movement disorders in patients with peripheral facial palsy
Authors: Valls‐Solé Josep , Montero Jordi
Published: December 2003

Acute unilateral facial paralysis is usually a benign neurological condition that resolves in a few weeks. However, it can also be the source of a transient or long‐lasting severe motor dysfunction, featuring disorders of automatic and voluntary movement. This review is organized according to the two most easily recognizable phases in the evolution of facial paralysis: (1) Just after presentation of facial palsy, patients may exhibit an increase in their spontaneous blinking rate as well as a sustained low‐level contraction of the muscles of the nonparalyzed side, occasionally leading to blepharospasm‐like muscle activity. This finding may be due to an increase in the excitability of facial motoneurons and brainstem interneurons mediating trigeminofacial reflexes. (2) If axonal damage has occurred, axonal regeneration beginning at approximately 3 months after the lesion leads inevitably to clinically evident or subclinical hyperactivity of the previously paralyzed hemifacial muscles. The full‐blown postparalytic facial syndrome consists of synkinesis, myokymia, and unwanted hemifacial mass contractions accompanying normal facial movements. The syndrome has probably multiple pathophysiological mechanisms, including abnormal axonal branching after aberrant axonal regeneration and enhanced facial motoneuronal excitability. Although the syndrome is relieved with local injections of botulinum toxin, fear of such uncomfortable contractions may lead the patients to avoid certain facial movements, with the implications that this behavior might have on their emotional expressions. © 2003 Movement Disorder Society
Paraneoplastic movement disorder in a patient with non‐Hodgkin's lymphoma and CRMP‐5 autoantibody
Authors: Samii Ali , Dahlen Debra D. , Spence Alexander M. , Maronian Nicole C. , Kraus Eric E. , Lennon Vanda A.
Published: December 2003

The paraneoplastic autoantibody, collapsin response‐mediator protein (CRMP)‐5 immunoglobulin G (IgG), is specific for neuronal cytoplasmic CRMP‐5, and is usually associated with small‐cell lung carcinoma or thymoma. We report on details of a movement disorder that followed anti‐B‐cell therapy in a patient with lymphoma, and was accompanied by CRMP‐5 IgG. © 2003 Movement Disorder Society
A 3D cylindrical finite element model for thick curved beam stress analysis
Authors: Rattanawangcharoen N. , Bai H. , Shah A. H.
Published: December 2003

A finite element model is proposed to perform stress analysis for thick curved beams and panels subjected to various types of loadings. The model has 18 nodes in a three‐dimensional cylindrical co‐ordinates system. Three stress components on radial surface (σrr, τrθ, and τrz) and three displacement components (ur, uθ, and uz) are used as nodal degrees of freedom. Therefore, the continuity condition for both stresses and displacements is achieved in the radial direction. Formulation of nodal shape functions and equilibrium equations are based on three‐dimensional elasticity theory and a minimum potential energy method. The accuracy of the method is verified with the standard test problems and exact solutions from the theory of elasticity. The model shows no locking phenomena. Convergence is investigated and the application to layered composite panel is illustrated. Copyright © 2003 John Wiley & Sons, Ltd.
A boundary integral for gradient averaging in two dimensions: application to polygonal regions in granular materials
Authors: Kuhn Matthew R.
Published: December 2003

A boundary integral is derived for averaging the gradients of a function within a two‐dimensional (2D) region. The double integral uses the boundary derivative of the function to compute the average gradients, and it accounts for possible discontinuities in the function along the boundary. The integral reduces to a simple matrix expression for a polygonal region. When applied to a 2D granular material, the matrix expression can be used to compute the averaged local strains within polygonal void regions (particle clusters). In this situation, a realistic calculation of strain must account for the discontinuous movements among rigid particles along the polygon sides, as might occur if the particles are rotating as well as translating. The matrix expression provides a simple and efficient means of correcting the average strain to account for the discontinuous movements. For a cluster of circular disks, the correction is a consequence of the rolling and sliding among particles. The significance of the correction is illustrated with an example simulation of a large dense assembly of circular disks. Although the paper applies the boundary integral to the kinematics of granular regions, the integral will likely find other applications in 2D situations that involve discontinuous fields. Copyright © 2003 John Wiley & Sons, Ltd.
Workplace giving: A case study of the Combined Federal Campaign
Authors: Bowman Woods
Published: December 2003

The Combined Federal Campaign gives federal workers an opportunity to contribute to local charities by payroll deduction. This article provides an overview of the size and scope of this program.
Current practices in allocation of fundraising expenditures
Authors: Hager Mark A.
Published: December 2003

Much of what donors and regulators know about nonprofit organizations comes from public financial statements. Do charities track and report their expenses correctly?
Performance of household grid‐connected PV system in Thailand
Authors: Adhikari Sushil , Kumar S. , Siripuekpong Pinij
Published: December 2003

This paper presents the performance of a 2·88 kWp household grid‐connected PV system installed in a house at Bangkok. This was one of the 10 houses identified for a household rooftop PV grid‐connected demonstration project by the Electricity Generating Authority of Thailand in 1997. Data measured over 12 months was used to estimate the PV array output, inverter output, inverter efficiency, system efficiency, yields (reference yield, array yield, final yield) performance ratio (PR) and the losses. The variations of these parameters over time indicate that the yields are high during June and July in Bangkok. The annual final yield and the average performance ratio were found to be 1166 kW h/kWp and 0ċ73 respectively. The monthly highest final yield was 129 kW h/kWp during June and July. The inverter efficiency was greater than 80% throughout the study period and the maximum system efficiency was 5·4%. The result of the study indicates that the system installed in Bangkok worked satisfactorily. Following the success of the demonstration project, a second phase of 50 households has recently been initiated. Copyright © 2003 John Wiley & Sons, Ltd.
Screen‐printed epitaxial silicon thin‐film solar cells with 13·8% efficiency
Authors: Rentsch J. , Bau S. , Huljić D. M.
Published: December 2003

Amidst the different silicon thin‐film systems, the epitaxial thin‐film solar cell represents an approach with interesting potential. Consisting of a thin active c‐Si layer grown epitaxially on top of a low‐quality c‐Si substrate, it can be implemented into solar cell production lines without major changes in the current industrial process sequences. Within this work, ∼30‐μm‐thick epitaxial layers on non‐textured and highly doped monocrystalline Czochralski (Cz) and multicrystalline (mc) Si substrates have been prepared by CVD. Confirmed efficiencies of 13·8% on Cz and 12·3% on mc‐Si substrates have been achieved by applying an industrial process scheme based on tube and in‐line phosphorus diffusion, as well as screen‐printed front and back contacts fired through a SiNx anti‐reflection coating. An extensive solar cell characterisation, including infrared lock‐in thermography and spectral response measurements is presented. Copyright © 2003 John Wiley & Sons, Ltd.
Family‐centered positive psychology: Focusing on strengths to build student success
Authors: Sheridan Susan M. , Warnes Emily D. , Cowan Richard J. , Schemm Ariadne V. , Clarke Brandy L.
Published: December 2003

Family‐centered positive psychology (FCPP) is defined as a framework for working with children and families that promotes strengths and capacity building within individuals and systems, rather than one focusing solely on the resolution of problems or remediation of deficiencies. This approach to family‐based services is predicated on the belief that child and family outcomes will be enhanced if members participate in identifying needs, establishing social supports and partnerships, and acquiring new skills and competencies, rather than simply receiving services from professionals. In this article, we present a rationale for FCPP, outline its primary principles, highlight one model for working with families that exemplifies FCPP practice, and illustrate its use through an authentic data‐based case study. © 2004 Wiley Periodicals, Inc. Psychol Schs 41: 7–17, 2004.
Structured extracurricular activities among adolescents: Findings and implications for school psychologists
Authors: Gilman Rich , Meyers Joel , Perez Laura
Published: December 2003

One factor that contributes to adolescent positive mental health is active engagement. Engagement is defined as any activity that is initiated to attain an outcome. In general, two forms of activities exist that correspond with engagement: solitary, non‐structured, and non‐cooperative pursuits, often without adult supervision (e.g., playing video games, watching television) and highly structured, collaborative activities that are under the guidance of a competent set of adults (i.e., structured extracurricular activities, or SEAs). Although large amounts of time spent in unstructured activities is related to negative psychosocial outcomes, participation in SEAs has been related to a variety of positive outcomes for students. This paper reviews current research regarding adolescent participation in SEAs and its effects on academic and personal‐social variables (i.e., self‐concept, life satisfaction), as well as potential preventive effects for youths considered to be “at‐risk” for negative developmental outcomes. The paper also examines research investigating the potential benefits and shortcomings of different types of SEAs. Finally, suggestions for future research and school‐based preventive intervention are presented. © 2004 Wiley Periodicals, Inc. Psychol Schs 41: 31–41, 2004.
Positive psychology goes to school: Are we there yet?
Authors: Clonan Sheila M. , Chafouleas Sandra M. , McDougal James L. , Riley‐Tillman T. Chris
Published: December 2003

Implicit within a perspective of positive psychology is the assumption that environments can be promoted to foster individual strengths through a preventative focus and the development of positive institutions. Given that the development of positive institutions has direct implications for school psychology, this paper begins to draw attention to the potential of positive psychology within school systems. Throughout the paper, it is suggested that a focus on schools may serve as the nexus between the movement in positive psychology searching to promote positive human development and the institutions that could serve as the vehicle for this development. Historic and emerging trends are examined, with particular attention to how positive psychology could promote the development of positive schools (institutions) that foster success for all students. Specifically, the parallel histories of discontent with deficit‐oriented practice in the fields of mental health and school psychology are reviewed, and precursors to building and maintaining positive institutions that focus on working within the existing system to promote lasting change are explored. © 2004 Wiley Periodicals, Inc. Psychol Schs 41: 101–110, 2004.
Synthesis and association of poly(N,N‐dimethylacrylamide) copolymers with perfluorocarbon pendent groups connected through polyethylene‐glycol tethers
Authors: Da Jie , Hogen‐Esch Thieo E.
Published: December 2003

The synthesis is reported of copolymers of N,N‐dimethylacrylamide (DMA) and methacrylates containing 2,2′‐dihydroperfluorodecanoyl (RF) groups separated from the methacrylate by long polyethylene glycol (PEG) tether groups (between 1000 and 14,000 Da). At concentrations of between 1 and 8 wt % the copolymers with macromonomer contents of 1 mol % or less give gels in organic solvents such as dioxane, THF, or methanol, as well as in water. Given the low molecular weights, this indicates very efficient association of very low numbers of RF groups. Association and gel formation is enormously enhanced in the presence of longer PEG tethers. This is consistent with smaller poly(N,N,‐dimethylacrylamide) (PDMA) intermolecular excluded volume effects that are mediated by the longer PEG tethers and possibly by the incompatibility of PEG and PDMA that may lead to the formation of PEG microdomains. This increases the local concentrations of the RF groups in the PEO domains that are not diluted by the PDMA chains, as would be the case in the absence of PEG tethers. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 360–373, 2004
Synthesis of transparent thermoplastic polyurethane elastomers
Authors: Sonnenschein Mark F. , Rondan Nelson , Wendt Benjamin L. , Cox J. Mark
Published: December 2003

Thermoplastic polyurethanes were synthesized from poly(propylene glycol)‐block‐poly(ethylene glycol) polyols and hybrid hard segments that combined at least two different chain extenders. The combination of hard segments allowed for modification of elastomer performance and processing not achievable by any single hard segment. The combination of hard segments modulated hard‐segment energies that were directly related to elastomer performance. Special attention is paid to obtaining optically transparent elastomers with this technique. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 271–278, 2004
Crystallization of a vitrified hindered phenol within chlorinated polyethylene and its effects on dynamic mechanical properties
Authors: Wu Chifei , Akiyama Saburo
Published: December 2003

The effects of heat treatment below the melting point of 3,9‐bis{1,1‐dimethyl‐2[β‐(3‐tert‐butyl‐4‐hydroxy‐5‐methylphenyl)propionyloxy]ethyl}‐2,4,8,10‐tetraoxaspiro[5,5]‐undecane (AO‐80) on the thermal and dynamic mechanical properties and microstructure of chlorinated polyethylene (CPE) filled with vitrified AO‐80 particles were investigated. The initial AO‐80 was a complete crystal, whereas AO‐80 obtained by cooling from its melting state was amorphous. The vitrified AO‐80 particles could crystallize again in a CPE matrix by an annealing treatment, but this crystal was different from the initial AO‐80 in the microstructure. In addition, the incorporation of CPE chains caused a dramatic increase in the modulus. As a result, the AO‐80 crystal particles that contained some CPE chains acted as multifunctional crosslinks, and the CPE/AO‐80 hybrid was found to be a new type of elastomer. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 209–215, 2004
Interfacial slip at the thermotropic liquid‐crystalline polymer/poly (ethylene naphthalate) interface
Authors: Lam Y. C. , Jiang L. , Li L. , Yue C. Y. , Tam K. C. , Hu X.
Published: December 2003

The unique rheological properties of a thermotropic liquid‐crystalline polymer (TLCP) were first studied. The thermal and shear history of the TLCP was found to play a critical role in its rheological properties. Crystallites were observed in the TLCP melt even above the melting temperature detected by differential scanning calorimetry. Because interfacial slip had long been suggested as an important reason for viscosity reduction in TLCP/thermoplastic blends, for the first time, interfacial slip at the TLCP/poly(ethylene naphthalate) (PEN) interface was investigated with an energy model. The model quantified the degree of interfacial slip at the TLCP/PEN interface by an energy factor. The calculated energy factors revealed a high degree of interfacial slip at the TLCP/PEN interface. It was proposed that the high rigidity of rodlike TLCP chains and their alignment parallel to the interface prevented mutual entanglements at the TLCP/PEN interface. The lack of mutual entanglements promoted the interfacial slip. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 302–315, 2004
Behavior of cellulose in NaOH/Urea aqueous solution characterized by light scattering and viscometry
Authors: Zhou Jinping , Zhang Lina , Cai Jie
Published: December 2003

Cellulose was dissolved in 6 wt % NaOH/4 wt % urea aqueous solution, which was proven by a 13C NMR spectrum to be a direct solvent of cellulose rather than a derivative aqueous solution system. Dilute solution behavior of cellulose in a NaOH/urea aqueous solution system was examined by laser light scattering and viscometry. The Mark–Houwink equation for cellulose in 6 wt % NaOH/4 wt % urea aqueous solution at 25 °C was [η] = 2.45 × 10−2 weight‐average molecular weight (Mw)0.815 (mL g−1) in the Mw region from 3.2 × 104 to 12.9 × 104. The persistence length (q), molar mass per unit contour length (ML), and characteristic ratio (C∞) of cellulose in the dilute solution were 6.0 nm, 350 nm−1, and 20.9, respectively, which agreed with the Yamakawa–Fujii theory of the wormlike chain. The results indicated that the cellulose molecules exist as semiflexible chains in the aqueous solution and were more extended than in cadoxen. This work provided a novel, simple, and nonpollution solvent system that can be used to investigate the dilute solution properties and molecular weight of cellulose. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 347–353, 2004
Effect of end‐tethered polymers on surface adhesion of glassy polymers
Authors: Sides Scott W. , Grest Gary S. , Stevens Mark J. , Plimpton Steven J.
Published: December 2003

The adhesion between a glassy polymer melt and substrate is studied in the presence of end‐grafted chains chemically attached to the substrate surface. Extensive molecular dynamics simulations have been carried out to study the effect of the areal density ∑ of tethered chains and tensile pull velocity v on the adhesive failure mechanisms. The initial configurations are generated using a double‐bridging algorithm in which new bonds are formed across a pair of monomers equidistant from their respective free ends. This generates new chain configurations that are substantially different than the original two chains such that the systems can be equilibrated in a reasonable amount of cpu time. At the slowest tensile pull velocity studied, a crossover from chain scission to crazing is observed as the coverage increases, while for very large pull velocity, only chain scission is observed. As the coverage increases, the sections of the tethered chains pulled out from the interface form the fibrils of a craze that are strong enough to suppress chain scission, resulting in cohesive rather than adhesive failure. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 199–208, 2004
Preserved diffusion capacity in children with cystic fibrosis
Authors: Merkus Peter J.F.M. , Govaere Elke S.J. , Hop Wim H. , Stam Henk , Tiddens Harm A.W.M. , de Jongste Johan C.
Published: December 2003

Early detection of progressive lung disease in cystic fibrosis (CF) may lead to better treatment and prognosis. Routine lung function indices may be relatively insensitive markers of peripheral airway obstruction and alveolar collapse. We hypothesized that the single‐breath diffusion capacity of the lung for carbon monoxide (DLCO) would change before tests of airway function in patients with CF. We assessed lung function longitudinally in 53 children with CF during a mean period of 3.8 years to determine whether the diffusion capacity of the lung becomes abnormal before more conventional indices of lung function do. Within patients, DLCO was slightly elevated and remained stable, while froced expired volume in 1 sec (FEV1) and forced vital capacity (FVC) declined progressively (mean individual decline, −1.8% and −0.8% of predicted). Cross‐sectionally, this decline was faster (mean group decline −3.8% and −2.8% of predicted), indicating an additional cohort effect. Normalized diffusion capacity at an early stage of CF is slightly elevated and is preserved in spite of progressive obstructive lung disease. This can be attributed to alterations in pulmonary and bronchial circulation due to loss of function and/or number of alveolar units. Diffusion capacity at rest does not appear to be a suitable early marker of progressive deterioration of CF lung disease. Pediatr Pulmonol. 2004; 37:56–60. © 2004 Wiley‐Liss, Inc.
Mucoepidermoid carcinoma of the bronchus presenting with a negative chest X‐ray and normal pulmonary function in two teenagers: Two case reports and review of the literature
Authors: Giusti Robert J. , Flores Raja M.
Published: December 2003

Two adolescents presented with a history of dyspnea upon exertion and cough. In both cases, the chest X‐ray and pulmonary function testing, including flow‐volume loop, were normal. A bronchial tumor was diagnosed by CT scan, which was ordered after each patient had an episode of hemoptysis. The sedimentation rate was the only abnormal laboratory test in both cases. Mucoepidermoid carcinoma of the bronchus, a rare tumor in childhood, was found at pathology in both cases. There was no evidence of metastases to local lymph nodes or distal sites. There were 47 previously reported cases in children. Recurrent pneumonia and persistent cough were the most common presenting findings. These tumors are of low‐grade malignant potential but they can become locally invasive, extending into cartilage and surrounding soft tissue. Prognosis is good with complete resection. Pediatr Pulmonol. 2004; 37:81–84. © 2004 Wiley‐Liss, Inc.