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Quantity
Kinds of Quantity Terms modified by Quantity Selected AbstractsPROLIFERATION OF ACADEMIC JOURNALS: EFFECTS ON RESEARCH QUANTITY AND QUALITYMETROECONOMICA, Issue 4 2007Rajeev K. Goel ABSTRACT There have been significant structural changes in research markets in recent years reflected in the increase in the number of academic journals. This paper uses a differential game model of authors and journal editors to examine the effects of an increase in competition among academic journals. Does an increase in the number of academic journals lead to an increase in scholarly articles published? Will an increase in publishing outlets adversely affect research quality? The results show greater competition does not affect research output and in fact enhances research quality. The number of journals and the relative discount rates of authors and editors are crucial determinants of the effects of competition. [source] A comparison of epidemiologic and immunologic features of bronchiolitis caused by influenza virus and respiratory syncytial virusJOURNAL OF MEDICAL VIROLOGY, Issue 2 2005Roberto P. Garofalo Abstract We studied epidemiologic and immunologic factors in infants with bronchiolitis caused by influenza virus. The proportion of these infants who were male and who had an immediate family member with a history of asthma was similar to that of a control group of infants with respiratory syncytial virus (RSV) bronchiolitis. In subjects with influenza virus infection, concentrations of the beta chemokine macrophage inflammatory protein-1alpha (MIP-1,), but not other beta chemokines, in nasopharyngeal secretions (NPS) were greater among infants with more severe, hypoxic bronchiolitis than in subjects with mild, nonhypoxic bronchiolitis, or upper respiratory tract infection alone. Quantities of MIP-1, were also correlated with lower values of oxygen saturation. These findings point out epidemiologic and immunologic similarities between bronchiolitis caused by influenza and RSV, and suggest that host factors are more important than the nature of the infecting virus in the development of severe forms of bronchiolitis caused by influenza and RSV. J. Med. Virol. 75:282,289, 2005. © 2004 Wiley-Liss, Inc. [source] Studies on dimerisation of tocopherols under the influence of methyl linoleate peroxidesMOLECULAR NUTRITION & FOOD RESEARCH (FORMERLY NAHRUNG/FOOD), Issue 2 2003Marek Gogolewski Abstract The stability of plant oils is related to the level of polyunsaturated fatty acids and the presence of native antioxidants , especially tocopherols. During storage, lipids or the fat products undergo oxidation and tocopherol dimers and trimers are formed. These compounds possess reducing and antioxidant properties and participate in oxidation clearly inhibiting this process. In the present study, the correlation between levels of peroxides formed during autoxidation of methyl linoleate and simultaneous decomposition of tocopherols was examined. The peroxide value was investigated. Quantities of decomposed tocopherols and formation of their dimers were determined by high-performance liquid chromatography (HPLC). Mass spectrum analysis confirmed that the analysed compounds were dimers. Dimerisation of ,-T begins at the smaller quantity of the methyl linoleate peroxides than dimerisation of ,-T. At the beginning of methyl linoleate autoxidation dimerization of ,-T in relation to its loss was smaller. The quantity of ,-T dimers with ether bonds in total dimers pointed to faster binding of phenoxy radicals than transformation into the phenyl ones. ,-T dimers with phenyl bonds constitute about 65% of the total. The quantity of peroxides in methyl linoleate, necessary for quantitative and qualitative changes of homologous tocopherols, decreased from ,-T to ,-T. [source] Persistence and efficacy of two diatomaceous earth formulations and a mixture of diatomaceous earth with natural pyrethrum against Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae) on wheat and maizePEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 5 2006Basileios J Vayias Abstract Laboratory tests were conducted to assess the insecticidal and residual effects of three diatomaceous earth (DE) formulations, Insecto®, PyriSec® and SilicoSec®, against Tribolium confusum Jacquelin du Val on wheat and maize. Quantities of wheat and maize were treated with the above formulations at 500, 1000 and 1500 mg kg,1 and stored at 25 °C and 55% relative humidity (RH). Samples were taken on the day of storage and every 30 days until completion of a 360 day period of storage. Adults of T. confusum were exposed to these samples at 25 °C and 55% RH and the mortality was measured after 24 and 48 h and 7 and 14 days of exposure. Adult mortality was higher on wheat than on maize. At the beginning of the storage period, mortalities after 14 day exposure on maize treated with the highest rate were 60, 63 and 81% for Insecto®, PyriSec® and SilicoSec® respectively, while on wheat the mortality was 100% for all DEs. On the same commodities 360 days after treatment the respective mortality figures for wheat were 99, 98 and 100%, while in the case of maize they did not exceed 7%. Generally, mortality at exposures ,48 h decreased with increasing storage time. Furthermore, although mortality on wheat increased with dose, the increase in DE dose from 1000 to 1500 mg kg,1 resulted in only a small increase in mortality. Thus a DE treatment of 1000 mg kg,1 was shown to provide long-term protection of wheat against T. confusum, although higher DE application rates and exposure intervals are needed for a satisfactory level of protection of maize against this pest. Copyright © 2006 Society of Chemical Industry [source] Spouting Enhancement by Addition of Small Quantities of Liquid to Gas-Spouted BedsTHE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 5 2006Y. Nagahashi Abstract The addition of liquid water to beds of polystyrene particles exceeding 3 mm in diameter enhanced spouting by causing a decrease in the minimum spouting velocity. While the degree of enhancement is quantitatively comparable to what we reported previously for fluidized beds of large light hydrophobic particles, the mechanism is quite different. Enhancement of spouting takes place because the liquid congregates at the spout-annulus interface, forming an effective nearly-impermeable draft tube which then increases the velocity of the gas up the spout. L'ajout d'eau liquide à des lits de particules de polystyrène de plus de 3 mm de diamètre améliore le jaillissement en causant une diminution de la vitesse de jaillissement minimale. Alors que le degré d'amélioration est du point de vue quantitatif comparable à ce que nous avons indiqué antérieurement pour des lits fluidisés à larges particules hydrophobes légères, le mécanisme est différent. L'amélioration du jaillissement se produit parce que le liquide s'agglomère à l'interface jet-espace annulaire, formant un tube d'aspiration quasi imperméable efficace, ce qui a pour effet d'accroître la vitesse du gaz en haut du jet. [source] Coarse woody debris in Australian forest ecosystems: A reviewAUSTRAL ECOLOGY, Issue 8 2005GEMMA WOLDENDORP Abstract Coarse woody debris (CWD) is the standing and fallen dead wood in a forest and serves an important role in ecosystem functioning. There have been several studies that include estimates of CWD in Australian forests but little synthesis of these results. This paper presents findings from a literature review of CWD and fine litter quantities. Estimates of forest-floor CWD, snags and litter from the literature are presented for woodland, rainforest, open forest and tall open forest, pine plantation and native hardwood plantation. Mean mass of forest floor CWD in Australian native forests ranged from 19 t ha,1 in woodland to 134 t ha,1 in tall open forest. These values were generally within the range of those observed for similar ecosystems in other parts of the world. Quantities in tall open forests were found to be considerably higher than those observed for hardwood forests in North America, and more similar to the amounts reported for coniferous forests with large sized trees on the west coast of the USA and Canada. Mean proportion of total above-ground biomass as forest floor CWD was approximately 18% in open forests, 16% in tall open forests, 13% in rainforests, and 4% in eucalypt plantations. CWD can be high in exotic pine plantations when there are considerable quantities of residue from previous native forest stands. Mean snag biomass in Australian forests was generally lower than the US mean for snags in conifer forests and higher than hardwood forest. These results are of value for studies of carbon and nutrient stocks and dynamics, habitat values and fire hazards. [source] Successful removal of p -quinone with chitosan in an aqueous phase in relation to degree of deacetylationBIOFACTORS, Issue 1-4 2004Tomoki Takahashi Abstract Phenol oxidant is successfully removed by using chitosan particles in the aqueous phase. Removal of p -quinone by chitosan from crab shells was investigated kinetically from molecular weight (MW) of chitosan, deacetylation degree (DD) and reaction temperature. The rate constant assuming first-ordered reaction on removal of p -quinone in aqueous phase primarily depended on the MW of chitosan, not on the DD. Quantities of chitosan exceeding 5 × 105 MW are able to obtain a sufficiently high rate constant (10,3 s,1). At higher temperatures, higher rate constants were obtained in the entire experimental MW and DD. The activation energy obtained was 43.8 kJ·mol,1. [source] Determination of amino acid enantiomers in human urine and blood serum by gas chromatography,mass spectrometryBIOMEDICAL CHROMATOGRAPHY, Issue 3 2001Hans Brückner Amino acid (AA) enantiomers were determined as N(O) -pentafluoropropionyl-(2)-propyl esters by chiral gas chromatography,mass spectrometry (GC-MS) in 24,h samples of the urine of three healthy volunteers and in their blood sera. In urine the largest amounts were determined for D -Ser (64,199,µmol/day) and D -Ala (24,138,µmol/day). In blood sera, D -Ala (2.3,4.2,µmol/L) and D -Ser (1.0,2.9,µmol/L) were most abundant. Varying amounts of the D -enantiomers of Thr, Pro, Asx, Glx, Phe, Tyr, Orn and Lys were also found, albeit not in all urines and sera. Further, enantiomers were quantified in urine samples of two volunteers fasting for 115,h. Quantities of renally excreted D -AAs decreased in fasting, although amounts of D -Ser (69 and 77,µmol/L urine) as well as other D -AAs were still detectable. Time-dependent analyses of urine showed that D -AAs are continuously excreted. Copyright © 2001 John Wiley & Sons, Ltd. [source] Alkoxycarbonylation Reactions Performed Using Near-Stoichiometric Quantities of CO.CHEMINFORM, Issue 51 2007Chad M. Kormos Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] The Impact of Imperfect Processes on Production Run TimesDECISION SCIENCES, Issue 4 2000Tonya Boone ABSTRACT This paper investigates the interaction between the economics of production and imperfections in the production process. Specifically, this paper is the first to devise a model in an attempt to provide managers with guidelines to choose the appropriate production run times to buffer against both the production of defective items and stoppages occurring due to machine breakdowns. In addition to providing several structural properties of the model, we show that a manager will always incur a cost penalty when (s)he uses the results of two oft-cited models-the EMQ (Economic Order/Manufacturing Quantity) and the NR-E (No-Resumption, Exponential machine breakdown)-to determine production run times. [source] Rumination as a predictor of drinking behaviour in alcohol abusers: a prospective studyADDICTION, Issue 6 2010Gabriele Caselli ABSTRACT Aims To investigate the role of depression and rumination in predicting drinking status (absence or presence of alcohol use) and level of alcohol use at 3, 6 and 12 months following a brief course of cognitive,behavioural therapy for alcohol abuse. Methods A total of 80 out-patients with a diagnosis of alcohol abuse completed measures of depression (Beck Depression Inventory), rumination (Ruminative Responses Scale) and alcohol use (Quantity,Frequency Scale). Results These indicated that rumination predicted drinking status and level of alcohol use at 3-, 6- and 12-month follow-up. The contribution of rumination was independent of depression and initial level of alcohol use. Conclusions The results confirm that rumination is an important prospective predictor of drinking status and level of alcohol use in alcohol abusers and highlight the potential relevance of targeting rumination in the treatment of alcohol abuse. [source] The Returns to the Quantity and Quality of Education: Evidence for Men in England and WalesECONOMICA, Issue 265 2000Colm Harmon Until the late 1960s, state schooling in England and Wales was determined by an ability test of pupils at age 11 which had an effect on both the quantity and quality of education. By estimating the relationship between earnings and earlier schooling during a period when school areas changed from selective to non-selective education, we consider how the returns to the quantity of education are confounded by differences in the quality of schooling and whether the effects of quality are confounded by its correlation with quantity. Our results confirm recent evidence that returns to education quantity are large and quality effects are small. [source] Quality, quantity, and impact in academic publicationEUROPEAN JOURNAL OF SOCIAL PSYCHOLOGY, Issue 2 2010Nick Haslam Publication records of 85 social-personality psychologists were tracked from the time of their doctoral studies until 10 years post-PhD. Associations between publication quantity (number of articles), quality (mean journal impact factor and article influence score), and impact (citations, h -index, g -index, webpage visits) were examined. Publication quantity and quality were only modestly related, and there was evidence of a quality-quantity trade-off. Impact was more strongly associated with quantity than quality. Authors whose records weighed quality over quantity tended to be associated with more prestigious institutions, but had lesser impact. Quantity- and quality-favoring publication strategies may have important implications for the shape and success of scientific careers. Copyright © 2009 John Wiley & Sons, Ltd. [source] Electronic Mail in Foreign Language Writing: A Study of Grammatical and Lexical Accuracy, and Quantity of LanguageFOREIGN LANGUAGE ANNALS, Issue 2 2000Manuela Gonzälez-Bueno The authors statistically analyzed the quality and quantity of discourse generated via the electronic and the traditional (i.e., paper-and-pencil) medium. The primary objective was to determine whether the use of electronic mail had any effect on grammatical accuracy, appropriate use of vocabulary, and language productivity. In addition, the participants completed a written survey at the end of the semester that elicited their opinions of the program's effectiveness. It was found that the electronic version of dialogue journals had a significantly positive effect on the amount of language generated by the students, and that it improved students' attitude towards learning and practicing the target language. However, the electronic version of dialogue journals did not seem to pose any significant advantage over the paper-and-pencil version with regard to lexical and grammatical accuracy. [source] Young mothers' involvement in a prenatal and postpartum support program,JOURNAL OF COMMUNITY PSYCHOLOGY, Issue 2 2010Xiaoli Wen The involvement of 124 young mothers in a doula support program was measured in two dimensions,quantity of program contact and quality of mother,doula helping relationship. The study examined each dimension's differential associations with maternal outcomes, as well as the moderating effects of mother characteristics on these associations. Quantity of program contact was related to the quality of helping relationship, especially when rated by doulas. Both quantity and quality of involvement predicted the maternal outcomes, although not always in the expected direction. For mothers with limited vocabulary skills and better connections with the baby's father, program contact was more likely to promote positive birth experiences. A negative association between program contact and parenting behaviors was observed among mothers who were less mature or had less positive social relationships. The study suggests the multidimensionality of program involvement and the complexity of interactions between program and participant factors in producing program outcomes. © 2010 Wiley Periodicals, Inc. [source] Quantity versus quality effects of generic advertising: The case of Norwegian salmonAGRIBUSINESS : AN INTERNATIONAL JOURNAL, Issue 1 2007Øystein Myrland In this article, a two-equation sample selection model is used to estimate a household demand function for salmon incorporating domestic generic advertising. The two-equation estimation procedure, based on purchase and unit value equations, allows us to handle heavily censored panel data for salmon purchases by Norwegian households and the quality effects simultaneously. Unit values of the aggregated salmon commodity calculated from the observed expenditures and quantities are hypothesized to represent the average quality of the purchased commodity. Advertising effects on both purchases and unit values are investigated. The model also allows us to separate the effects of conditional purchases and purchase probabilities. Results indicate that most (76%) of the advertising effect is through the change of nonpurchase occasions to purchase occasions, and that generic salmon advertising induces Norwegian households to spend more money on salmon. However, advertising causes households to select more expensive products rather than increasing their purchased quantities. [EconLit citations: D12, C24]. © 2007 Wiley Periodicals, Inc. Agribusiness 23: 85,100, 2007. [source] The Correlation Between Skeletal Weathering and DNA Quality and Quantity,JOURNAL OF FORENSIC SCIENCES, Issue 4 2009Lisa M. Misner M.S. Abstract:, Mitochondrial DNA analysis of skeletal material is invaluable in forensic identification, although results can vary widely among remains. Previous studies have included bones of different ages, burial conditions, and even species. In the research presented, a collection of human remains that lacked major confounders such as burial age, interment style, and gross environmental conditions, while displaying a very broad range of skeletal degradation, were examined for both mitochondrial DNA (mtDNA) quality and quantity. Overall skeletal weathering, individual bone weathering, and bone variety were considered. Neither skeletal nor bone weathering influenced DNA quality or quantity, indicating that factors that degrade bone do not have the same effect on DNA. In contrast, bone variety, regardless of weathering level, was a significant element in DNA amplification success. Taken together, the results indicate that neither skeletal nor individual bone appearance are reliable indicators of subsequent mtDNA typing outcomes, while the type of bone assayed is. [source] The Great Capitol Hill Baby Sitting Co-op: Anecdote or Evidence for the Optimum Quantity of Money?JOURNAL OF MONEY, CREDIT AND BANKING, Issue 6 2007THORSTEN HENS microeconomic foundation of money; optimum quantity of money; experimental monetary economics This paper studies a centralized market with idiosyncratic uncertainty and money as a medium of exchange from a theoretical as well as an experimental perspective. In our model, prices are fixed and markets are cleared by rationing. We prove the existence of stationary monetary equilibria and of an optimum quantity of money. The rational solution of our model, which is based on the assumption of individual rationality and rational expectations, is compared with actual behavior in a laboratory experiment. The theoretical results are strongly supported by this experiment. [source] Influence of a Drinking Quantity and Frequency Measure on the Prevalence and Demographic Correlates of DSM-IV Alcohol DependenceALCOHOLISM, Issue 5 2009Katherine M. Keyes Background:, Recent research suggests that adding a quantity/frequency alcohol consumption measure to diagnoses of alcohol use disorders may improve construct validity of the diagnoses for Diagnostic and Statistical Manual of Mental and Behavior Disorders (DSM-V). This study explores the epidemiological impact of including weekly at-risk drinking (WAD) in the DMS-IV diagnostic definition of alcohol dependence via 3 hypothetical reformulations of the current criteria. Methods:, The sample was the National Epidemiologic Survey on Alcohol and Related Conditions, a nationally representative sample with 43,093 adults aged >18 in the U.S interviewed with the Alcohol Use Disorder and Associated Disabilities Interview Schedule IV. The current (DSM-IV) definition of alcohol dependence was compared with 4 hypothetical alcohol dependence reformulations that included WAD: (1) WAD added as an eighth criteria; (2) WAD required for a diagnosis; (3) adding abuse and dependence criteria together, and including WAD with a 3 of 12 symptom threshold; (4) adding abuse and dependence criteria together, and including WAD with a 5 of 12 symptom threshold. Results:, The inclusion of at-risk drinking as an eighth criterion of alcohol dependence has a minimal impact on the sociodemographic correlates of alcohol dependence but substantially increases the prevalence of dependence (from 3.8% to 5.0%). At-risk drinking as a required criterion or as part of a diagnosis that combines abuse with dependence criteria with a higher threshold (5+ criteria) decreases prevalence and has a larger impact on sociodemographic correlates. Blacks, Hispanics, and women are less likely to be included in diagnostic reformulations that include WAD, whereas individuals with low-income and education are more likely to remain diagnosed. Conclusions:, Including WAD as either a requirement of diagnosis or as an additional criterion would have a large impact on the prevalence of alcohol dependence in the general population. The inclusion of a quantity/frequency requirement may eliminate false positives from studies of alcohol disorder etiology and improve phenotype definition for genetic association studies by reducing heterogeneity in the diagnosis, but may also reduce eligibility for treatment services among women and racial/ethnic minorities compared. [source] Can We Identify Genes For Alcohol Consumption In Samples Ascertained For Heterogeneous Purposes?ALCOHOLISM, Issue 4 2009Narelle K. Hansell Background:, Previous studies have identified evidence of genetic influence on alcohol use in samples selected to be informative for alcoholism research. However, there are a growing number of genome-wide association studies (GWAS) using samples unselected for alcohol consumption (i.e., selected on other traits and forms of psychopathology), which nevertheless assess consumption as a risk factor. Is it reasonable to expect that genes contributing to variation in alcohol consumption can be identified in such samples? Methods:, An exploratory approach was taken to determine whether linkage analyses for heaviness of alcohol consumption, using a sample collected for heterogeneous purposes, could replicate previous findings. Quantity and frequency measures of consumption were collected in telephone interviews from community samples. These measures, and genotyping, were available for 5,441 individuals (5,067 quasi-independent sibling pairs). For 1,533 of these individuals, data were collected on 2 occasions, about 8.2 years apart, providing 2 datasets that maximize data collected at either a younger or an older age. Analyses were conducted to address the question of whether age and heavier levels of alcohol consumption effects outcome. Linkage results were compared in the younger and older full samples, and with samples in which approximately 10, 20, and 40 of drinkers from the lower end of the distribution of alcohol consumption were dropped. Results:, Linkage peaks varied for the age differentiated samples and for percentage of light drinkers retained. Larger peaks (LOD scores >2.0) were typically found in regions previously identified in linkage studies and/or containing proposed candidate genes for alcoholism including AGT, CARTPT, OPRD1, PIK3R1, and PDYN. Conclusions:, The results suggest that GWAS assessing alcohol consumption as a covariate for other conditions will have some success in identifying genes contributing to consumption-related variation. However, sample characteristics, such as participant age, and trait distribution, may have substantial effects on the strength of the genetic signal. These results can inform forthcoming GWAS where the same restrictions apply. [source] Prospective Study of Alcohol Consumption in the United States: Quantity, Frequency, and Cause-Specific MortalityALCOHOLISM, Issue 3 2008Rosalind A. Breslow Background:, Alcohol average volume (quantity multiplied by frequency) has been associated with mortality in drinkers. However, average volume may mask associations due to quantity or frequency alone. Methods:, We prospectively assessed relationships between alcohol quantity and frequency, and mortality from all-causes, cardiovascular disease, cancer, and other-causes in a cohort created by linking the 1988 National Health Interview Survey (response rate 87%) to the National Death Index through 2002. Participants were 20,765 current drinkers age , 18 years. At 14-year follow-up 2,547 had died. Results:, For quantity, among men who consumed ,5 drinks (compared to 1 drink) on drinking days, adjusted relative risks (RR) of mortality were: for cardiovascular disease, 1.30 [95% confidence interval (CI) 0.96,1.75; p for linear trend (p -trend) = 0.0295], for cancer, 1.53 (95% CI 1.11,2.09; p -trend = 0.0026), and for other-causes, 1.42 (95% CI 1.08,1.87; p -trend = 0.0029); among women for other-causes, 2.88 (95% CI 1.61,5.12; p -trend = 0.0010). For frequency, among men in the highest frequency quartile (compared to the lowest), RR were: for cardiovascular disease, 0.79 (95% CI 0.63,0.99; p -trend = 0.0330), for cancer, 1.23 (95% CI 0.95,1.59; p -trend = 0.0461), and for other-causes, 1.30 (95% CI 1.01,1.67; p -trend = 0.0070); among women, for cancer, 1.65 (95% CI 1.12,2.45, p -trend = 0.0031). Average volume obscured effects of quantity alone and frequency alone, particularly for cardiovascular disease in men where quantity and frequency trended in opposite directions. Conclusions:, Alcohol quantity and frequency were independently associated with cause-specific mortality. Accumulating evidence of their differential effects may, in the future, be useful for clinical and public health recommendations. [source] Variation of Apigenin Quantity in Diploid and Tetraploid Chamomilla recutita (L.) RauschertPLANT BIOLOGY, Issue 4 2000vehlíková Abstract: Apigenin, a pharmacologically important flavonoid of the chamomile plant, was analyzed at two ploidy levels during a three-year period. This flavonoid accumulates in the ligulate florets of the anthodium. Higher percentages of apigenin were found in the ligulate florets of a diploid cultivar, in comparison with tetraploid plants. However, when the total apigenin (mg of compound) in the anthodium was evaluated, tetraploid individuals accumulated significantly more flavonoid. Moreover, in contrast to morphological quantitative characteristics of the anthodium, which varied significantly in different years, apigenin percentage in the ligulate florets was constant and not influenced by environmental conditions. Apigenin content was also found to change during inflorescence ontogeny. It represents the highest percentage of dry mass in young developing florets and anthodia of both cultivars. The total apigenin content of the anthodium, however, increases during flowering, although at later stages apigenin forms only a minor part of ligulate floret and anthodium dry mass. [source] Productivity loss in the workforce: associations with health, work demands, and individual characteristicsAMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 1 2009Seyed Mohammad Alavinia MD Abstract Background Decreased productivity at work is an important consequence of the presence of health problems at work. Methods The study population consisted of 2,252 workers in 24 different companies in The Netherlands in 2005,2006 (response 56%). Self-reported loss of productivity on the previous workday was measured on a 10-point numerical rating scale by the Quantity and Quality method. Logistic regression analysis was used to explore the associations between work demands, health problems, individual characteristics, and lifestyle factors with the occurrence of productivity loss. Results About 45% of the workers reported some degree of productivity loss on the previous workday, with an average loss of 11%. Moderate and severe functional limitations due to health problems (OR,=,1.28 and 1.63, respectively) and lack of control at work (OR,=,1.36) were associated with productivity loss at work with population attributable fractions of 7%, 6%, and 16%, respectively. Conclusion Productivity losses at work frequently occur due to health problems and subsequent impairments, and lack of control over the pace and planning of work. This will substantially contribute to indirect costs of health problems among workers. Am. J. Ind. Med. 52:49,56, 2009. © 2008 Wiley-Liss, Inc. [source] Optimal Price and Quantity of Refurbished ProductsPRODUCTION AND OPERATIONS MANAGEMENT, Issue 3 2006Jumpol Vorasayan Many retail product returns can be refurbished and resold, typically at a reduced price. The price set for the refurbished products affects the demands for both new and refurbished products, while the refurbishment and resale activities incur costs. To maximize profit, a manufacturer in a competitive market must carefully choose the proportion of returned products to refurbish and their sale price. We model the sale, return, refurbishment, and resale processes in an open queueing network and formulate a mathematical program to find the optimal price and proportion to refurbish. Examination of the optimality conditions reveals the different situations in which it is optimal to refurbish none, some, or all of the returned products. Refurbishing operations may increase profit or may be required to relieve a manufacturing capacity bottleneck. A numerical study identifies characteristics of the new product market and refurbished products that encourage refurbishing and some situations in which small changes in the refurbishing cost and quality provoke large changes in the optimal policy. [source] A Search Model Where Consumers Choose Quantity Based on Expected PriceTHE JOURNAL OF INDUSTRIAL ECONOMICS, Issue 4 2003Paolo Buccirossi I describe a price game in which consumers face search costs and base their quantity decision on the expected price. Because of search costs, the choice of the firm they will buy from is described by a random process. I show that the expected equilibrium price is above the monopoly price. This result does not change if demand comes from a small share of perfectly informed consumers with zero search costs. [source] Sleep habits in Nigerian undergraduatesACTA NEUROLOGICA SCANDINAVICA, Issue 1 2010O. S. A. Oluwole Background,,, Quantity of night sleep is shorter than 8 h in several developed countries, but similar data is not available for most African countries. The objective of this study was to describe the quantity of night sleep, factors that are associated with non-restorative sleep, and sleep habits in a population of undergraduates in Nigeria. Methods,,, Questionnaires were used to collect information about bedtimes, waketimes, intra-night awakenings, non-restorative sleep, and afternoon naps over a period of 14 days. Results,,, Mean duration of night sleep was 6.2 h (median 6.0, range 4.5,9.3), while mean duration of daytime naps was 70 min (median 75, range 10,315). Duration of night sleep was associated with day of the week and gender, but not with BMI. Non-restorative sleep, which occurred 25% of total sleep times, was associated with night sleep ,5 h, hypnotic use, alarm to wake, heavy workload, and afternoon naps. Intra-night sleep awakening occurred 58.5% of total sleep times. Afternon naps were taken by 225 (82%) of subjects. Conclusion,,, Duration of night sleep in this African population is not longer than the duration in Western countries. Intra-night awakening and non-restorative sleep; however, occur more frequently, and afternoon nap is usually in excess of 1 h. [source] ,Quantity over Quality': A Voice from the Third WorldCHEMISTRY & BIODIVERSITY, Issue 6 2005Mohamed Yalpani First page of article [source] Accuracy of Linear Measurement Provided by Cone Beam Computed Tomography to Assess Bone Quantity in the Posterior Maxilla: A Human Cadaver StudyCLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 4 2008Sophie Veyre-Goulet DDS ABSTRACT Purpose: The aim of this study was to assess, for implant placement in the posterior maxilla, the accuracy of linear measurements provided by cone beam computed tomography (CBCT) using an image intensifier tube and television (TV) chain as an X-ray detector despite a loss of contrast resolution. The NewTom® 9000 (Quantitative Radiology, Verona, Italy) was used to explore the posterior maxilla. Materials and Methods: Fourteen measurements were taken in three dry maxillaries. On every anatomical site, three fiducial markers were placed on the bony crest to define a plane. Dry maxillaries were submitted to CBCT imaging examination. The maxillaries were then sawn according to the previously defined planes, and bone height and width were assessed using a caliper. The same measurements were taken on images. Results: Clinical analysis demonstrated no difference between real measurements and image measurements. Conclusions: Although cadaver bone density may not correspond to the density of vital bone, this in vitro study indicates that CBCT images provided by technique using image intensifier tube and TV chain as an X-ray detector are reliable to define the bone volume of the posterior maxilla for the purpose of planning the implant axis. [source] Clinical and histologic evidence of salivary gland restoration supports the efficacy of rituximab treatment in Sjögren's syndrome,ARTHRITIS & RHEUMATISM, Issue 11 2009J. Pijpe Objective To assess the effect of rituximab (anti-CD20 antibody) therapy on the (immuno)histopathology of parotid tissue in patients with primary Sjögren's syndrome (SS) and the correlation of histologic findings with the flow rate and composition of parotid saliva. Methods In a phase II study, an incisional parotid biopsy specimen was obtained from 5 patients with primary SS before and 12 weeks after rituximab treatment (4 infusions of 375 mg/m2). The relative amount of parotid parenchyma, lymphocytic infiltrate, and fat, and the presence/quantity of germinal centers and lymphoepithelial duct lesions were evaluated. Immunohistochemical characterization was performed to analyze the B:T cell ratio of the lymphocytic infiltrate (CD20, CD79a, CD3) and cellular proliferation in the acinar parenchyma (by double immunohistologic labeling for cytokeratin 14 and Ki-67). Histologic data were assessed for correlations with the parotid flow rate and saliva composition. Results Four patients showed an increased salivary flow rate and normalization of the initially increased salivary sodium concentration. Following rituximab treatment, the lymphocytic infiltrate was reduced, with a decreased B:T cell ratio and (partial) disappearance of germinal centers. The amount and extent of lymphoepithelial lesions decreased in 3 patients and was completely absent in 2 patients. The initially increased proliferation of acinar parenchyma in response to inflammation was reduced in all patients. Conclusion Sequential parotid biopsy specimens obtained from patients with primary SS before and after rituximab treatment demonstrated histopathologic evidence of reduced glandular inflammation and redifferentiation of lymphoepithelial duct lesions to regular striated ducts as a putative morphologic correlate of increased parotid flow and normalization of the salivary sodium content. These histopathologic findings in a few patients underline the efficacy of B cell depletion and indicate the potential for glandular restoration in SS. [source] Initialization Strategies in Simulation-Based SFE Eigenvalue AnalysisCOMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 5 2005Song Du Poor initializations often result in slow convergence, and in certain instances may lead to an incorrect or irrelevant answer. The problem of selecting an appropriate starting vector becomes even more complicated when the structure involved is characterized by properties that are random in nature. Here, a good initialization for one sample could be poor for another sample. Thus, the proper eigenvector initialization for uncertainty analysis involving Monte Carlo simulations is essential for efficient random eigenvalue analysis. Most simulation procedures to date have been sequential in nature, that is, a random vector to describe the structural system is simulated, a FE analysis is conducted, the response quantities are identified by post-processing, and the process is repeated until the standard error in the response of interest is within desired limits. A different approach is to generate all the sample (random) structures prior to performing any FE analysis, sequentially rank order them according to some appropriate measure of distance between the realizations, and perform the FE analyses in similar rank order, using the results from the previous analysis as the initialization for the current analysis. The sample structures may also be ordered into a tree-type data structure, where each node represents a random sample, the traverse of the tree starts from the root of the tree until every node in the tree is visited exactly once. This approach differs from the sequential ordering approach in that it uses the solution of the "closest" node to initialize the iterative solver. The computational efficiencies that result from such orderings (at a modest expense of additional data storage) are demonstrated through a stability analysis of a system with closely spaced buckling loads and the modal analysis of a simply supported beam. [source] | ||||||||||||||||||||||||||||||||||||||||||||||||||||