bluuebunny/crossref_metadata_2025 huggingface dataset:
Applications of Computational Fluid Dynamics (CFD) Tools for Gravity Concentrators in Coal Preparation
Authors: Xia Y. K.
Published: May 2007

Extensive progress has been made in using CFD tool in the simulation of multiphase flows in some gravity concentrators. Several case studies for calculation of multiphase flows by different numerical models in spiral, dense medium cyclone, water only cyclones, hindered-settling bed separator, heavy medium vessel and jig are reviewed. The Euler-Lagrange approach in calculation of the particle movement and particle-liquid coupling effect are also discussed. The limitation of Euler-Euler models in the treatment of the particles with a size distribution, and disadvantages of discrete element method (DEM) in description of the jigging processes will be presented. The successful two-dimensional simulation of the hindered-settling bed separator, heavy medium vessel and jig by Euler-Lagrange approach is also addressed.
Does It Pay To Pray? Costly Ritual and Cooperation
Authors: Ruffle Bradley J. , Sosis Richard
Published: May 2007

Time-consuming and costly religious rituals pose a puzzle for economists committed to rational choice theories of human behavior. We propose that either through selection or a causal relationship, the performance of religious rituals is associated with higher levels of cooperation. To test this hypothesis we design field experiments to measure the in-group cooperative behavior of members of religious and secular Israeli kibbutzim, communal societies for which mutual cooperation is a matter of survival. Our results show that religious males (the primary practitioners of collective religious ritual in Orthodox Judaism) are more cooperative than religious females, secular males and secular females. Moreover, the frequency with which religious males engage in collective religious rituals predicts well their degree of cooperative behavior.
Digital Literacy Research from an International and Comparative Point of View
Authors: Pietrass Manuela
Published: May 2007

The fear of a growing digital divide between those having access to the Internet and those who do not results from the still uneven distribution of digital media. Though the number of Internet users is rapidly growing, there is evidence for the further existence of a digital divide caused by the lack of digital literacy. Thus, the digital divide cannot be closed by access alone and becomes a matter of media education. To find appropriate methods for increasing digital literacy demands knowledge about the ways users deal with computers and the Internet. This knowledge is gained by empirical research in different formal and non-formal contexts of computer and Internet use. This introductory article to a special issue of Research in Comparative and International Education devoted to ‘Digital Literacy Research’ gives an insight into international data on Internet use and outlines a theoretical framework of digital literacy. It also discusses the single studies collected in the special issue. It shows that further research will profit by an international and comparative approach which considers national, cultural, social and age differences between the users.
Children's Writing Processes When Using Computers: Insights Based on Combining Analyses of Product and Process
Authors: Gnach Aleksandra , Wiesner Esther , Bertschi-Kaufmann Andrea , Perrin Daniel
Published: May 2007

Children and young people are increasingly performing a variety of writing tasks using computers, with word processing programs thus becoming their natural writing environment. The development of keystroke logging programs enables us to track the process of writing, without changing the writing environment for the writers. In the myMoment schools project, children in primary school grades one to five were provided with a web-based interactive writing environment, which they could use to read and write stories and comments. The parallel study on myMoment suggests that interviews and analyses of writing processes can provide detailed information about the effect that writing environment and instructions have on writing. An individual case study illustrates the potential that triangulating product and process analyses can offer in the teaching of literacy skills at elementary school level.
The Use of Computer Tools in Implementation Projects in Schools
Authors: Gräsel Cornelia
Published: May 2007

In recent years, some endeavours have been made to overcome the gap between theoretical and practical knowledge. In many countries projects have been conducted that aim to disseminate research-based knowledge in the practical field of education. This article presents an approach to the implementation of research results. This approach is referred to as ‘symbiotic implementation’, because teachers and researchers are seen as partners and aim to jointly advance teaching and learning in classrooms. Teachers and researchers form a community of learners with the goal of enhancing the quality of teaching and learning in classrooms. In addition to face-to-face cooperation, the computer is used as a tool for communication and collaboration in teachers' communities of learners. The computer provides several tools which facilitate different functions for the communities: (a) mutual sharing of information among participants, (b) planning and documenting lessons, and (c) commenting upon and revising products. In two studies in Germany the process of teacher collaboration was investigated. As expected, face-to-face collaboration was pivotal for the success of the implementation. In contrast, teachers used the available computer tools only to inform themselves or to obtain material; the cooperation and collaboration tools were only used to a small extent.
Cardiac valve calcifications and predictive parameters in hemodialysis patients
Authors: Selcoki Yusuf , Turgut Faruk , Kanbay Mehmet , Ozkara Adem , Tekin Oguz , Uz Burak , Akcay Ali
Published: May 2007

Cardiac valvular calcification is frequent among hemodialysis (HD) patients. The presence of valvular calcification can help identify HD patients with a higher risk for cardiovascular diseases. Our aim was to determine the prevalence of valvular calcification (VC) in our maintenance hemodialysis (HD) population and to examine some possible etiologic factors for its occurrence. We studied forty-four patients on hemodialysis (23 women and 21 men; mean age 57 ± 18 year; mean HD duration 34 ± 28 months). Valvular calcification (VC) was observed in 21 patients (48%). Of these patients, 6 patients (13%) had mitral valvular calcification, 9 patients (20%) had aortic valvular calcification, and 6 patients (13%) had calcification of both valves. The patients with VC were older than patients without VC (66±14 vs. 50±18). The patients with aortic calcification had longer HD duration than others (48±29 vs. 27±24 months). Patients with VC had higher systolic and diastolic blood pressures than patients without VC. The patients with mitral calcification had higher C-reactive protein (CRP) levels (14 ± 13 vs. 7 ± 7). No significant differences were found with respect to calcium, phosphorus, parathyroid hormone, alkaline phosphatase and mean Ca × P product. Our study confirmed that there is an increased prevalence of VC in HD patients. Age is a risk factor for cardiac VC in HD patients. Longer HD duration was associated with aortic valve calcification. In addition, elevated level of CRP is associated with mitral valve calcification in HD patients.
Low-Blank Crucible for Argon Extraction from Minerals at Temperatures up to 1550°C
Authors: Halas Stanislaw
Published: May 2007

The new version of a double-vacuum crucible for fusion of small samples of refractory minerals has been described recently by Halas (2006). This novel type of high temperature crucible was further improved in the following important points: (1) The expensive material, tantalum, was replaced by much cheaper molybdenum which also appears to be significantly less corrosive in the presence of hot boron nitride ceramic used as the insulator, and (2) a versatile temperature controller was assembled from commercially available components.
TL Ages of Loesses from the Last Two Glacials in Se Poland
Authors: Kusiak Jarosław , Łanczont Maria , Wilgat Maria
Published: May 2007

Loesses cover a large area in SE Poland so their exploration is an important part of the palaeogeographical studies on Pleistocene. The research involves stratigraphic problems. At present, luminescence dating provides the greatest number of chronostratigraphic data concerning loesses. In this work we report TL ages of loesses from the last two glacial cycles in SE Poland, obtained in the TL Laboratory of the Department of Physical Geography and Palaeogeography, Maria Curie-Skłodowska University in Lublin after 1993. Samples for TL dating were collected in 11 loess profiles (2-9 samples in each site) in order to obtain additional information for stratigraphic interpretations deduced from paleopedological, lithological, structural, and other data. Basing on the comparison of 54 TL ages, we can determine age intervals, in which the dating results of similar values assemble, and then get general information about the periods of intensified Aeolian accumulation related to defined stratigraphic units. The TL ages of all samples were obtained using the total-bleach method (TB) for the determination of the equivalent dose.
K-Ar Dating of Amphiboles from Andesite of Complex Dyke in Dubie (Southern Poland)
Authors: Lewandowska Anna , Banaś Michał , Zygoń Karolina
Published: May 2007

This study presents the results of radiometric K-Ar measurements on separated amphiboles from the andesite of the Dubie complex dyke. The data obtained cover the period of (291.3 ± 6.4) Ma, which corresponds to Carboniferous-Permian transition. The age is contemporaneous to the rhyodacitic and basaltoid volcanism of the Kraków region.
Building an Empirical Case for Ecological Democracy
Authors: Mitchell Ross E.
Published: April 2007

The concept of ecological democracy has been employed to illustrate how rapid ecological and environmental change poses significant problems for existing democratic structures. If the term is to prove useful, however, it must be better conceptualized and empirically tested. This article addresses this challenge by first outlining key empirical intersections of environment and democracy, then providing a working definition of ecological democracy. Four plausible research hypotheses are also recommended to guide future analyses of ecological democracy.
Characterization of surfaces of CTMP fibers using inverse gas chromatography combined with multivariate data analysis
Authors: Börås Linda , Sjöström Jaana , Gatenholm Paul
Published: May 2007

The effect of CTMP fiber surface composition on interactions with various solvents was characterized using inverse gas chromatography, and the data obtained with this method was evaluated using multivariate data analysis. The amount of extractives was shown to have a major influence on the degree of interactions between fiber and solvents. There were also discemible effects of counter-ions to acidic groups and mild peroxide bleaching on surfaces. IGC combined with multivariate data analysis may be a useful tool in explaining variations in e.g. retention and sizing on the board machine.
Effect of headbox slice geometry during the stratified forming of woodfree paper
Authors: Lloyd Mike D. , Norman Bo
Published: May 2007

Stratified forming, or the simultaneous forming of a multi-layer sheet from a single headbox, can produce an heterogeneous surface due to flocs from the different layers being mixed together in the headbox jet. In this paper we investigated the effect of the slice geometry on the layer mixing process. Sharply contracting slice lips downstream of the vane tips appeared to reduce layer mixing. while parallel slice lips downstream of the vane tips appeared to increase layer mixing. However the type of slice lips had little effect on layer mixing if the vanes finished outside the headbox. A narrower slice opening reduced layer mixing in all cases. Reducing the jet speed from 830 mlmin to 540 m/min had little effect on layer mixing and paper properties. Sharply contracting slice lips improved the small scale formation. The higher consistency associated with a narrower slice opening worsened the large scale formation, but had no effect on small scale formation. The jet speed did not alter the formation within the range tested.
Surface characterization of a rosin sizing agent in paper by means of EPMA, ESCA and TOF-SIMS
Authors: Ozaki Yasushi , Sawatari Atsushi
Published: May 2007

EPMA(e1ectronprobe micro analysis), ESCA (electron spectroscopy for chemical analysis) and TOF-SIMS (time of flight type secondary ion mass spectrometry) were used to detect the distribution of a rosin sizing agent in paper. For EPMA we labelled paper samples with osmium tetroxide which enabled the detection of rosin in the XY direction of the paper sheet. For ESCA we labelled paper samples with fluorine which also enabled the detection of rosin. At the same time, the ESCA angle-dependent technique was used to obtain depth profiles of the rosin. Also, distribution images of rosin on an extremely thin ( 1 nm) surface layer were made observable by monitoring fragment ions from the rosin with TOF-SIMS. By using EPMA, a notable difference in rosin distribution was shown on the pulp fiber. However, according to the TOF-SIMS examination, the rosin was shown to be distributed relatively even in an extremely thin surface layer. The ESCA angle- dependent technique showed that rosin was present mainly on the outer surface layer.
Thermodynamic parameters governing the stereoselective degradation of arylglycerol-B-aryl ether bonds in milled wood lignin under kraft pulping conditions
Authors: Ahvazi Behzad C. , Argyropoulos Dimitris S.
Published: May 2007

During this investigation, softwood (picea mariana) milled wood lignin was subjected to kraft pulping conditions at the temperature range 100-160 oC, for variable lengths of time. After quantitative isolation of the treated lignins, they were subjected to 31PNMR analyses which allowed the absolute rates of scission of the erythro and thewo diastereomers of the arylglycerol-B-aryl ether structures present in lignin to be derived.The plots of the kinetic data revealed that two kinetic regimes operate i.e. an initial fast phase that is followed by another slower phase. In agreement with previous accounts, the rate constants for these scission reactions were found to follow a pseudo-first-order rate law, during both phases. Rate constant data obtained during this effort, invariably indicated that the erythro isomers of the R-0-4 units of softwood milled wood lignin cleave faster than their thr-eo counterparts during both phases. At elevated temperatures (160 "C) the difference was found to be augmented. The general stability of the threo diastereomers toward kraft pulping seems to be the manifestation of a considerably slower reaction of the pulping reagents with the threo diastereomers of the B-aryl ethers. Arrhenius and Eyring plots o i these data supplied the complete profile of thermodynamic parameters governing this commercially important ether scission reaction.
Wirkungen der Bildungsarbeit im Stadtzürcher Wald auf den Alltag in Familie und Schule: ein Beitrag zur Wirkungsforschung | The Effectiveness of Environmental Education on Everyday Family Life and School Behaviour. A Contribution to Effectiveness Research
Authors: Kamber Evelyn
Published: May 2007

The impact of one-day visits at a forest school on children was investigated by means of a survey among teachers and parents. The children showed an increased environmental consciousness and positive effects on their social behaviour.
Molecular Barbed Wire: Threading and Interlocking for the Mechanical Reinforcement of Polymers
Authors: Tsui N. T. , Torun L. , Pate B. D. , Paraskos A. J. , Swager T. M. , Thomas E. L.
Published: April 2007

The incorporation of pendant iptycene units into polyesters creates a novel polymer‐chain contour resembling “molecular barbed wire.” These types of units contain a unique structural property called the internal molecular‐free volume (IMFV) and have been shown to induce steric interactions between polymer chains through the minimization of the IMFV. This process creates a sterically interconnected polymer‐chain network with high ductility because of two new mechanisms: molecular threading and molecular interlocking. The ability for these mechanisms to enhance the mechanical properties of polyesters is robust across concentration and processing conditions. The size, shape, and concentration of these pendant units affect the mechanical behavior, and results indicate that the larger units do not necessarily produce superior tensile properties. However, the molecular‐barbed‐wire architecture consistently produces enhanced mechanical properties compared to the reference polyester. The particular stress–strain response can be tailored by minute changes to the periphery of the iptycene unit.
Job stress and depressive symptoms among Japanese fire fighters
Authors: Saijo Yasuaki , Ueno Takeji , Hashimoto Yoshihiro
Published: April 2007

Background

Associations between job stresses, as assessed by theoretical job stress model and depressive symptoms among fire fighters have not been fully investigated. The purpose of this study is to clarify the factors of job stress that influence the depressive symptoms in Japanese fire fighters.

Methods

The subjects involved 1,672 fire fighters from a local government. The questionnaire comprised age, gender, job type, job class, martial status, smoking, and drinking habit, the Center for Epidemiologic Studies Depression Scale (CES‐D), and The National Institute for Occupational Safety and Health (NIOSH) generic job questionnaire.

Results

A group showing depressive symptoms (CES‐D ≥ 16) included 373 subjects (22.3%). In a multivariate logistic regression analysis, high variance in workload, high intergroup conflict, high role conflict, and low self‐esteem had significantly higher odds ratio for depressive symptoms.

Conclusions

High variance in workload, high intergroup conflict, high role conflict, and low self‐esteem were significantly related to depressive symptoms among Japanese fire fighters. Further prospective studies are needed to clarify the influence of these stress factors on other health outcomes, and to elucidate whether alleviation of these stress factors improve the mental health among fire fighters. Am. J. Ind. Med. 50:470–480, 2007. © 2007 Wiley‐Liss, Inc.
Factors associated with back problems among emergency medical technicians
Authors: Studnek Jonathan R. , Crawford J. Mac
Published: April 2007

Introduction

Back problems are a common complaint among emergency medical technicians (EMTs). It is hypothesized that the likelihood of reporting back problems will be associated with the individual and work‐related characteristics of a national sample of EMTs.

Methods

A case‐control analysis was performed on 579 EMTs wherein cases were the 104 subjects who reported new back problems in 2004. Controls were 475 subjects who reported no back problems in 2003 and 2004.

Results

EMTs dissatisfied with their current assignment were significantly more likely to report back problems (OR = 9.33; 95% CI = 3.04–28.67), as were EMTs reporting good or fair fitness when compared to excellent fitness (OR = 3.39; 95% CI = 1.54–7.45, OR = 3.43; 95% CI = 1.37–8.56).

Conclusions

Results from this analysis suggest that there are two modifiable factors associated with self‐reported back problems among EMTs, satisfaction with current assignment and self‐reported physical fitness. Am. J. Ind. Med. 50:464–469, 2007. © 2007 Wiley‐Liss, Inc.
Development of a decision aid to address racial disparities in utilization of knee replacement surgery
Authors: Weng Haoling H. , Kaplan Robert M. , Boscardin W. John , MacLean Catherine H. , Lee Irene Y. , Chen Weiling , Fitzgerald John D.
Published: April 2007

Objective

Previous studies suggest that poorer knowledge and expectations about surgical outcomes may be responsible for low rates of total knee replacement (TKR) among African American males. The goal of this study was to pilot test the scope, acceptability, and efficacy of an educational videotape and tailored TKR decision aid designed to reduce disparities in TKR knowledge and expectations.

Methods

African American and Caucasian male veteran volunteers ages 55–85 years with moderate to severe knee osteoarthritis (OA) were recruited. During group meetings, patients viewed a video about knee OA treatments and were provided a personalized arthritis report that presented predicted patient outcomes should they decide to undergo TKR. Patients completed baseline and postintervention questionnaires that included an adapted Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) instrument to measure post‐TKR expectations (0–100 scale with higher scores reflecting poorer outcomes).

Results

A total of 102 patients (54 African American, 48 Caucasian) completed the baseline survey and 64 patients attended the intervention. There were no significant differences by race between patients completing and those dropping out of the study. At baseline (n = 102), African American patients expressed lower expectations about post‐TKR outcomes than did Caucasian patients for both pain (WOMAC score 41 versus 34; P = 0.18) and physical function expectations (WOMAC score 38 versus 30; P = 0.13). Among African Americans who underwent the intervention, expected pain and physical function improved to 31 (P = 0.04 versus baseline) and 30 (P = 0.09 versus baseline), respectively. Caucasian patients' expectations changed little.

Conclusion

Disparities in baseline knowledge and expectations about TKR may be improved with the combined educational video and tailored decision aid.
Churg‐Strauss syndrome with poor‐prognosis factors: A prospective multicenter trial comparing glucocorticoids and six or twelve cyclophosphamide pulses in forty‐eight patients
Authors: Cohen Pascal , Pagnoux Christian , Mahr Alfred , Arène Jean‐Pierre , Mouthon Luc , Le Guern Véronique , André Marie‐Hélène , Gayraud Martine , Jayne David , Blöckmans Daniel , Cordier Jean‐franÇois , Guillevin Loïc ,   The French Vasculitis Study Group
Published: April 2007

Objective

To compare long and short durations of adjunctive cyclophosphamide for the treatment of severe Churg‐Strauss syndrome (CSS).

Methods

In this prospective multicenter therapeutic trial, 48 patients with CSS with at least 1 poor‐prognosis factor at baseline were treated with glucocorticoids and either 12 or 6 intravenous cyclophosphamide pulses.

Results

At 8 years, complete remission rates and severe side effects of therapy were comparable for both groups. The overall difference in relapses was not significant between the 12‐pulse and the 6‐pulse regimens (P= 0.07), but when considering only the number of mild relapses this difference became statistically significant (P< 0.02). Although the total number of inclusions was not reached, the study was stopped prematurely in response to the superiority of the 12‐pulse regimen.

Conclusion

We concluded that 12 cyclophosphamide pulses were better able to control severe CSS than a 6‐pulse regimen. The optimal duration of therapy remains to be determined.
Assessing chronic joint pain: Lessons from a focus group study
Authors: Gooberman‐Hill Rachael , Woolhead Gillian , MacKichan Fiona , Ayis Salma , Williams Susan , Dieppe Paul
Published: April 2007

Objective

To explore the pain experience of persons with chronic pain of the hip or knee in the context of self‐assessment instruments commonly used to assess pain severity in individuals with osteoarthritis.

Methods

Participants who reported that they currently had either hip or knee pain were recruited from the UK Somerset and Avon Survey of Health. A total of 28 participants (14 men and 14 women, ages 57–89 years) took part in 6 focus groups stratified according to pain site and severity. Using the “questerviews” technique, participants described and discussed their experience of joint pain in the context of standard self‐assessment questionnaires: the Hip Disability and Osteoarthritis Outcome Score and the Knee Injury and Osteoarthritis Outcome Score. The focus groups were audio recorded and transcribed. Data were analyzed by identifying emergent codes that were grouped and compared, resulting in the identification of key categories.

Results

Both knee pain and hip pain participants expressed similar pain experiences. Four key categories were identified, all of which impacted upon participants' responses to the standardized questionnaires: pain is intermittent and variable, pain elsewhere in the body influences the experience of joint pain, pain is inextricable from function, and adaptation and avoidance strategies modify the experience of pain.

Conclusion

The assessment or measurement of pain should take into account the importance of pain experience as well as severity through use of patient narrative accounts.
Incidence of systemic lupus erythematosus in the United Kingdom, 1990–1999
Authors: Somers Emily C. , Thomas Sara L. , Smeeth Liam , Schoonen W. Marieke , Hall Andrew J.
Published: April 2007

Objective

To estimate the annual incidence of systemic lupus erythematosus (SLE) over a 10‐year period in the UK, and to examine age‐, sex‐, and region‐specific rates.

Methods

The study was based on the UK General Practice Research Database (GPRD), which covers ∼5% of the UK population. We estimated SLE incidence rates, during the period 1990–1999, among persons registered with practices contributing to the GPRD, representing >33 million person‐years of observation.

Results

A total of 1,638 patients with incident SLE (1,374 females, 264 males) were identified. The age‐standardized SLE incidence in the UK during the 1990s was 7.89 per 100,000 (95% confidence interval [95% CI] 7.46, 8.31) for females and 1.53 per 100,000 (95% CI 1.34, 1.71) for males (overall female‐to‐male ratio 5.2:1). Peak incidence occurred at age 50–54 years for females and 70–74 years for males. There was a small but insignificant increase of SLE incidence over the 10 years among females but not males. No clear association between latitude and SLE incidence was found, but regional variations existed, with age‐standardized rates ranging from 3.56 per 100,000 (95% CI 3.00, 4.13) for the West Midlands to 7.62 per 100,000 (95% CI 5.59, 9.65) for Northern Ireland.

Conclusion

This study provides updated estimates of SLE incidence in the UK. Standard methodology throughout the study period and target population allowed for comparison of rates over time and across regions.
Role of age, sex, and obesity in the higher prevalence of arthritis among lower socioeconomic groups: A population‐based survey
Authors: Busija Lucy , Hollingsworth Bruce , Buchbinder Rachelle , Osborne Richard H.
Published: April 2007

Objective

To compare the prevalence of arthritis among population groups based on demographic, socioeconomic, and body mass index (BMI) characteristics; to investigate the combined influence of these factors on arthritis; and to assess the relationship between self‐reported health and psychological distress and arthritis.

Methods

Data from the Victorian Population Health Survey (n = 7,500) were used in the study. Psychological distress was assessed using the Kessler Psychological Distress scale, and self‐reported health was assessed by a single item. Multiple logistic regression was used to investigate the combined influence of demographic and socioeconomic factors and BMI on arthritis.

Results

Overall, 23% of Victorian adults (20% men and 26% women) reported having arthritis. The presence of arthritis was associated with high psychological distress (odds ratio [OR] 1.2; 95% confidence interval [95% CI] 1.1–1.4) and poor self‐reported health (OR 1.9; 95% CI 1.7–2.1). Increased prevalence of arthritis was found in older age groups, lower education and income groups, and in people who were overweight or obese. Women had higher risk of arthritis, even after adjustment for age, residence, education, occupation, income, and BMI. Age and BMI independently predicted arthritis for men and women. For men, higher risk of arthritis was also associated with lower income.

Conclusion

Arthritis is a highly prevalent condition associated with poor health and high psychological distress. Prevalence of arthritis is disproportionately high among women and individuals from lower socioeconomic backgrounds. As the prevalence of arthritis is predicted to increase, careful consideration of causal factors, and setting priorities for resource allocation for the treatment and prevention of arthritis are required.
Creatine supplements in patients with idiopathic inflammatory myopathies who are clinically weak after conventional pharmacologic treatment: Six‐month, double‐blind, randomized, placebo‐controlled trial
Authors: Chung Yuen‐li , Alexanderson Helene , Pipitone Nicoló , Morrison Catherine , Dastmalchi Maryam , Ståhl‐Hallengren Christina , Richards Selwyn , Thomas E. Louise , Hamilton Gavin , Bell Jimmy D. , Lundberg Ingrid E. , Scott David L.
Published: April 2007

Objective

To test the hypothesis that oral creatine supplements with exercise are more effective than exercise alone in improving muscle function in patients with established dermatomyositis or polymyositis receiving chronic medical therapies who are clinically weak yet stable.

Methods

In a 6‐month, 2‐center, double‐blind, randomized controlled trial, patients were randomized to receive oral creatine supplements (8 days, 20 gm/day then 3 gm/day) or placebo. All patients followed a home exercise program. The primary outcome was aggregate functional performance time (AFPT), reflecting the ability to undertake high‐intensity exercise. Secondary outcomes included a functional index measuring endurance and muscle bioenergetics on 31P magnetic resonance spectroscopy (31P MRS). Patients were receiving stable immunosuppressive treatment and/or corticosteroids.

Results

A total of 37 patients with polymyositis or dermatomyositis were randomized (19 to creatine, 18 to placebo); 29 completed 6 months. Intent‐to‐treat analyses demonstrated that AFPT improved significantly at 6 months with creatine (median decrease 13%, range –32–8%) compared with placebo (median decrease 3%, range –13–16%; P = 0.029 by Mann‐Whitney U test). A completer analysis also showed significant benefits from creatine (P = 0.014). The functional index improved significantly with both creatine and placebo (P < 0.05 by paired Wilcoxon's rank sum test), with a significant benefit between groups in the completer analysis only. Phosphocreatine/β‐nucleoside triphosphate ratios using MRS increased significantly in the creatine group (P < 0.05) but not in the control group. No clinically relevant adverse events were associated with creatine.

Conclusion

Oral creatine supplements combined with home exercises improve functional performance without significant adverse effects in patients with polymyositis or dermatomyositis. They appear safe, effective, and inexpensive.
Überprüfung des Tragverhaltens der Talbrücke Altwipfergrund
Authors: Novák Balthasar , Denzer Gundolf , Reichert Frank
Published: April 2007

Mitte der 1980er Jahre wurden in Frankreich erstmals Balkenbrücken als Doppelverbundsystem mit Trapezblechstegen im Brückenbau gebaut. Dieses Prinzip wurde kurze Zeit später in Japan übernommen, und dort wurden verstärkt Verbundbrücken dieser Art ausgeführt. Erste Überlegungen, in Deutschland solche Bauwerke, die eine enorme Trageffizienz aufweisen, zu realisieren, gab es ebenfalls bereits in den 1980er Jahren, doch leider wurde bis heute nur ein Tragwerk dieser Art, die Talbrücke Altwipfergrund, ausgeführt. Im Rahmen eines umfangreichen Kooperationsforschungsprojekts wurden prinzipielle Untersuchungen zum Tragverhalten und zur Detailausbildung von Brückenquerschnitten mit Trapezblechstegen durchgeführt, um diese interessante Bauweise mit einem verbesserten Bemessungskonzept konkurrenzfähig zu machen.

Weiterhin konnten die Erkenntnisse der numerischen Berechnungen und Laborversuche durch Messungen an der Talbrücke Altwipfergrund ergänzt werden, um Aussagen über das Tragverhalten zu treffen und aufbauend darauf Verbesserungspotential in den Bereichen Stegdicke, Wirkung der Vorspannung sowie deutliche Reduktion der Verbundmittel zwischen Steg und Betongurt für spätere Bauwerke dieser Art aufzeigen zu können.
Spannbandbrücke mit Kohlenstofffaser‐Lamellen
Authors: Schlaich Mike , Bleicher Achim
Published: April 2007

Im Bauwesen werden Kohlenstofffaser‐Lamellen bisher fast ausschließlich zur Verstärkung bestehender Bauwerke verwendet. Im Einsatz für den Neubau liegt ein großes, derzeit kaum genutztes, wirtschaftliches und konstruktives Potential. In der Versuchshalle des Instituts für Bauingenieurwesen der TU Berlin wurde nun eine Spannbandbrücke gebaut, deren primäres Tragelement aus Kohlenstofffaser‐Lamellen besteht. Spannbandbrücken gehören zu den leichtesten und elegantesten Brückenbauwerken. Die Geh‐ bzw. Fahrbahnplatten liegen direkt auf Bändern auf, die zwischen zwei Widerlagern spannen und dort verankert sind. Üblicherweise werden für die Bänder Stahlbleche oder ‐seile verwendet. Die Verwendung von Kohlenstofffaser‐Lamellen anstelle der Stahlbänder ermöglicht die Weiterentwicklung dieses Brückentyps. Im Vergleich zu gewöhnlichen Baustählen können mit diesem Werkstoff, wegen seiner ca. 10‐mal größeren Zugfestigkeit bei einem Fünftel des Eigengewichts, größere Spannweiten und schlankere Querschnitte realisiert werden.
Entwicklung einer Großelement‐Dämmtechnik (GEDT) mit Vakuum‐Isolationspaneelen (VIP) mit Anwendungsbeispielen – TEIL 1: Entwicklung und Technik
Authors: Reyer Eckhard , Kröger Rainer , Bamberger Cécile
Published: April 2007

Vor dem Hintergrund der Notwendigkeit nachhaltiger Reduzierung des Heizenergiebedarfs sowie auch zukünftig noch steigender Anforderungen an den Wärmeschutz der Gebäudehülle und der Tatsache fallweise nur zögerlicher Bereitschaft der Eigentümer ihre Altbausubstanz energetisch nachzurüsten, wurde die Großelement‐Dämmtechnik (GEDT) mit geschosshohen, raumbreiten Großelementen entwickelt, ursprünglich noch mit konventionellem Dämmstoff und nun auch mit Vakuum‐Isolationspaneelen (VIP): Dämmtechnisch hoch wirksam, geringer Platzbedarf, witterungsunabhängige Werksfertigung mit gleich bleibend hohem Qualitätsniveau, schneller Montage und Geringhalten von Lärm und Schmutz in der Sanierungsphase.

Nach kurzer Darstellung der Historie der GEDT werden im Teil 1 dieses Beitrags die Ergebnisse des Forschungsvorhabens zur Entwicklung einer GEDT mit VIP detailliert beschrieben, die Wärmedämmeigenschaften unter Ansatz unterschiedlicher VIP‐Dicken für fast beliebig gedämmte Althauswände im Rahmen einer Parameterbetrachtung diskutiert und im Teil 2 der erste Anwendungsfall – die energetische Sanierung dreier Wohnhäuser in Hofheim – vorgestellt. Gleichzeitig werden in Abschn.8 (Prognosen – Perspektiven – Ausblick) Rationalisierungsvorschläge – gewonnen aus der Erfahrung dieser GEDT‐VIP‐Anwendung – formuliert. Hierbei zeichnen sich – wenn die Beurteilung allein nach Kosten erfolgt – im Vergleich zur “GEDT mit VIP” gewisse Vorteile für eine Technik mit mittelformatigen, vorgefertigten, von Hand habbaren Dämmelementen mit VIP (“Komplettplattentechnik mit VIP”) ab.

Im Rahmen dieses Ausblicks wird auch eine Kostenuntergrenze für VIP‐Dämmung von Fassaden abschätzend angegeben. Dabei wird im bereits erwähnten Abschnitt 8 (Prognosen – Perspektiven – Ausblick) darauf hingewiesen, dass eine VIP‐Dämmung zur Zeit zwar im Regelfall zu deutlich höheren Kosten als eine vergleichbare konventionelle Dämmung führt, dass jedoch die Vorteile durch die geringere Dämmschichtdicke der VIP bei künftig sicher steigenden Ansprüchen an die Wärmedämmung (U‐Wert) überproportional zunehmen werden und dass langfristig der “pure” Kostenfaktor als Entscheidungskriterium für ein Dämmsystem zugunsten des Entscheidungskriteriums Raumbedarf in vielen Anwendungsfällen etwas mehr in den Hintergrund treten wird.
Some Applications of a Bivariate BOREL‐TANNER Distribution
Authors: Gupta R. P. , Jain G. C.
Published: April 2007

This paper considers the probability distribution of the number of customers served in the busy period of a single server queue with POISSON input and constant service time. Applications to traffic flow, semi‐infinite discrete dam and branching processes are described. It is shown that in many situations the bivariate BOREL‐TANNER distribution provides a better fit than the bivariate negative binomial distribution.
Partition of Genetic Variance for Sub‐Populations
Authors: Wessely E. Ch.
Published: April 2007

The variance between and within backcrosses of two populations is partitioned on the base of (I) multinomially distributed numbers of effects of specific chromosomes taking (II) recombination into account and on the base of (III) normally distributed sums of gene effects. The method of estimation makes use of a specific structure of data with backcross parents taken from different generations of random mating reproduction of crosses between the two populations.
A Report on a Monte Carlo Simulation of the Sampling Distribution of the Incidence Test and its Two Related Tests
Authors: Kannemann K.
Published: April 2007

A large‐scale (5000 throws) Monte Carlo simulation experiment was carried out to study the nature of the sampling distributions of the incidence test and its two related tests, the FRIEDMAN test and the dual test, and to evaluate the goodness of the proposed gamma approximation relative to the conventional chi‐square approximation. For all three tests, on the basis of the experimental results obtained for k = 3, 4, 5, and N = k(1) (120/k), the gamma approximation should be preferred over the chi‐square. Exact companion tabulations show that use of the chi‐square approximation entails an appreciable conservative bias. Extensive listings are provided of the moments of the experimental distributions of the three test statistics, and of the observed distributions of the corresponding gamma probabilities. The simulation experiment was run on a UNIVAC 1108 large‐scale computer system.
Theoretical Comparison of Grab and Composite Sampling Programs
Authors: Schaeffer D. J. , Janardan K. G.
Published: April 2007

A mathematical formula for determining the sampling frequency on the basis of the coefficients of variation of the various parameters of interest of water quality is developed.

The uncertainty or the variability of each sampling program is expressed as a function of the sampling design variable in order to construct a performance index which will enable one to select the best sampling program. The notion of information content is used as a basis for the performance index.

Under certain circumstances, the information content of a single composite is more than that of a single grab sample. However, the average of a series of grab samples provides more information than the average of a series of composite samples. This happens because the individual information content (entropy) of discrete portions of the composite sample are confounded in the average.

It is shown that if the variability of the proportions is greater than the upper limit (provided in Table 2), the information content of the composite, where the volume of each discrete portion is collected in proportion to the rate of flow (or discharge) at the time it is collected, is much smaller than that of the same number of grab samples or composite samples collected at constant volume‐constant time intervals.

Time constant, volume proportional‐to‐flow since last sample composites have the same disadvantages.
A Class of Phase‐Confounded Designs
Authors: El‐Beshir Z. A.
Published: April 2007

A new class of phase‐confounded designs is suggested. The class possesses the property that if in a year one of the rotations carries the test crop all other rotations also do. It also leads to equal block sizes when the rotations are structured in specified ways. Conditions under which designs of this class exist as well as method of constructing them are discussed.
Partial Diallel Cross in Multi‐environment
Authors: Dhillon B. S.
Published: April 2007

Analysis of partial diallel cross repeated over environments is discussed. Formulae are given to estimate the general combining ability effects and their interaction effects with environments. Analysis of variance table along with expected mean squares is given.
A New Functional Equation Analogous to CAUCHT‐PEXIDER Functional Equation and its Application
Authors: Janardan K. G.
Published: April 2007

The CAUCHY‐PEXIDER functional equationH(x±y)=F(x)G(y) is generalized to the formH((xc±yc)1/c) =F(x)G(y),c≠0, assuming the functionH(x) possesses a measurable majorant on a set of positive measure. The result is used to obtain a characterization of WEIBULL distribution. This functional equation is generalized to functions of vector variables.
An Unbalanced Nested Model with Random Effects Having Unequal Variances
Authors: Hussein Mohamed , Milliken George A.
Published: April 2007

Consider the model Yijk=μ + ai + bij + eijk (i=1, 2,…, t; j=1,2,…, Bi; k=1,2…,nij), where μ is a constant and a1,bij and eijk are distributed independently and normally with zero means and variances σ2adij and σ2, respectively, where it is assumed that the di's and dij's are known. In this paper procedures for estimating the variance components (σ2, σ2a and σ2b) and for testing the hypothesis σ2b = 0 and σ2a = 0 are presented. In the last section the mixed model yijk, where xijkkm are known constants and βm's are unknown fixed effects (m = 1, 2,…,p), is transformed to a fixed effect model with equal variances so that least squares theory can be used to draw inferences about the βm's.
A Propos de la Comparaison Graphique des Matrices de Variance
Authors: Escoufier Y. , L'Hermier H.
Published: April 2007

We compare variance‐covariance matrices considered as matrices of similarities between variables. The first part recalls the mathematical bases of the proposed method. The second part treats a set of meteorological data.
A Simple Nonparametric Test for Trend: An Example Based on a Biological Model for Cancer of the Pancreas
Authors: Reid N. , Levitt M. H.
Published: April 2007

In the statistical analysis of a recent series of experiments concerned with the morphogenesis of induced pancreatic neoplasms, the problem of testing for trend in a series of events was encountered. A nonparametric test for trend, similar to the well‐known TERPSTRA‐JONCKHEERE test, is proposed herein; its use is illustrated with data from the experiments.
Zahlenverhältnisse von Häufigkeiten
Authors: Hellmich K.
Published: April 2007

In evaluating data, one acknowledges as a scientist the superiority of the K‐procedure on account of the versatility of its application, e.g. in answering the question not only as to its causal context, in proving two features to be contemporaneous and equally strong effects of a material third factor, or in accordance with a “criterion of parallel problems”, but also in demonstrating the mutual matching of two frequency‐ratios and the matching of one frequency‐ratio with a given proportion, e.g. 3: 1, and the matching of a continuing proportion collected from observed frequencies with a given continuing proportion, e.g. 9:3:3: 1.

This is demonstrated in the examples in the literature, which hitherto have been treated only according to the classical procedure.
BAYESian Point Estimation of the Unknown Upper Limit of a Uniform Distribution
Authors: Jones P. W.
Published: April 2007

BAYESian fixed sample size and sequential procedures are considered for the estimation of the unknown parameter v of a uniform distribution over (0, v), under several loss functions.
Optimum Designs for Estimating the Variance Components in a Simple Variance Component Model (Model II), I
Authors: Herrendörfer G.
Published: April 2007

The methods of optimal designing of experiments proposed by WALD (1943) are used for determination of an Aσ2‐optimal concrete design for estimation of σ2′ = (σ, σ) in case of one‐way analysis of variance. Starting point of definition of the optimality criterion is a quadratic loss matrix.
On the KOLMOGOROV‐SMIRNOV Test for the POISSON Distribution with Unknown Mean
Authors: Campbell D. B. , Oprian C. A.
Published: April 2007

The standard tables for the KOLMOGOROV‐SMIRNOV test are valid only in the case of testing whether a set of observations is from a completely specified cumulative distribution, F0(X), with all parameters known. If the parameters are unknown and must be estimated from the sample, then the tables are not valid.

A table is given in this paper for use with the KOLMOGOROV‐SMIRNOV statistic in the case of testing whether a set of observations is from the POISSON distribution with an unknown mean that must be estimated from the sample. The table is obtained from a Monte Carlo calculation.
A General Computing Algorithm for Factor Analysis
Authors: Derflinger G.
Published: April 2007

A general algorithm for the factor analysis is developed, which contains the alpha factor analysis, the maximum likelihood method and the minres method as special cases. This algorithm, which is a multidimensional NEWTON algorithm, uses the partial derivatives of the reproduced communalities with respect to the inserted ones. The partial derivatives are got by means of the perturbation theory.
Quantitative Description and Mathematical Modelling of Biological Systems by Means of Nonlinear Approximations – Demonstrated at the Example of the Body Length Growth of Man
Authors: Peil J.
Published: April 2007

After general remarks upon the biomathematical tasks of quantitative description or mathematical modelling of biological systems and phenomena on different levels of organization the growth process of body length of human beings serves as illustration of the possibilities of such mathematical treatments. A short survey is given about the attempts of using differential equations for reflecting basic principles of growth processes. Further on analytical functions (as the solutions of growth differential equations) preferably may be used for an objective quantitative reproducing of measured courses of growth variables. The values of parameters contained in such expressions will be calculated by nonlinear fitting procedures. In nearly all cases we got a very high numerical precision in approximating parts of the body length growth process of man which extends from conception until the age of 18. Our attempts of a phenomenologic‐mathematical modelling of this growth process mean a subdividing of the whole process in single growth spurts with a symmetric‐sigmoidal shape of their courses, and describing the single spurt by a hyperbolic tangent function. An advantage of this kind of modelling is the fact that each of the terms is valid for the whole time interval of growth. Within the process of forming the model heuristical hints are taken into consideration arising from biological background and which would supply the possibility of interpretation and verification of the analyzed growth spurts.
A Stochastic Model for the Predatory Behaviour of Naive Spiderlings (Araneas: Salticidae)
Authors: Manly B. F. J. , Forster Lyn
Published: April 2007

A stochastic model is proposed for the hunting behaviour of jumping spiders when they are newly emerged from the egg‐sac. The model takes into account the fact that the spiders are often unsuccessful when they attempt to catch prey for the first time and also the fact that their rate of response to prey slows down with time if they are unsuccessful. It is shown that the spiderlings ability to catch perceived prey improves with the number of prey captured. The model has been fitted to experimental data using the method of maximum likelihood and a good fit has been obtained. The model could be used as part of a model for the whole predation system.