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Matched Pairs (matched + pair)
Selected AbstractsCombination of Enantioselective Metal Catalysis and Organocatalysis: Enantioselective Sequential Hydroformylation/ Aldol ReactionsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 4 2010Serghei Chercheja Abstract This work reports the possibility of controlling the sense of enantio- and diastereoinductions in the sequential hydroformylation and aldol reactions via the judicious combination of a chiral metal catalyst with a chiral organocatalyst. The diastereoselectivity of the reaction between styrene, syngas and acetone can be increased by using a matched pair of catalysts, [rhodium/(2S,4S)-Chiraphite]/(S)-organocatalyst and decreased, but not inverted, by using a mismatched pair of catalysts, [rhodium/(2R,4R)-Chiraphite]/(S)-organocatalyst. [source] Creating a High-Trust Organization: An Exploration into Organizational Policies that Stimulate Interpersonal Trust BuildingJOURNAL OF MANAGEMENT STUDIES, Issue 5 2008Frédérique Six abstract We examine empirically how an organization that deliberately enhances interpersonal trust to become a significant organizational phenomenon, is different from a similar organization without explicit trust enhancement policies. The point of departure is relational signalling theory, which says that trust is a function of consistently giving off signals that indicate credible concern, to potential trustors. A matched pair of two consulting organizations, with different trust policies but otherwise similar characteristics, were studied intensively, using survey research, participant observation and half-open interviewing, focused on the generation of trust and the handling of trouble when trust was threatened or destroyed. A higher stage of trust can be reached by an inter-related set of policies: promoting a relationship-oriented culture, facilitation of unambiguous signalling, consistent induction training, creating opportunities for meeting informally, and the day-to-day management of competencies. Such policies are in principle independent of recognized contextual contingencies. [source] Is reversal of large stock-price declines caused by overreaction or information asymmetry: Evidence from stock and option marketsTHE JOURNAL OF FUTURES MARKETS, Issue 4 2009Hyung-Suk Choi The role of option markets is reexamined in the reversal process of stock prices following stock price declines of 10% or more. A matched pair of optionable and nonoptionable firms is randomly selected when their price declines by 10% or more on the same date. The authors examine the 1,443 and 1,018 matched pairs of New York Stock Exchange/American Stock Exchange (AMEX) and National Association of Securities Dealers Automated Quotations firms over the period from 1996 to 2004. It was found that the positive rebounds for nonoptionable firms are caused by an abnormal increase in bid,ask spread on and before the large price decline date. On the other hand, the bid,ask spreads for optionable firms decrease on and before the large price decline date. An abnormal increase in the open interest and volume in the option market on and before the large price decline date was also found. Overall, the results suggest that the stock-price reversal neither is a result of overreaction nor can it be simply explained by the bid,ask bounce. © 2009 Wiley Periodicals, Inc. Jrl Fut Mark 29:348,376, 2009 [source] Examining the Antecedents and Consequences of CIO Strategic Decision-Making Authority: An Empirical Study,DECISION SCIENCES, Issue 4 2008David S. Preston ABSTRACT Despite the strategic importance of information technology (IT) to contemporary firms, chief information officers (CIO) often still have varying degrees of strategic decision-making authority. In this study, we apply the theory of managerial discretion to define CIO strategic decision-making authority and argue that the CIO's level of strategic decision-making authority directly influences IT's contribution to organization performance. We also draw on the power and politics perspective in the strategic decision-making literature to identify the direct antecedents to the CIO's strategic decision-making authority. A theoretical model is presented and empirically tested using survey data collected from a cross-industry sample of 174 matched pairs of CIOs and top business executives through structural equation modeling. The results suggest that organizational climate, organizational support for IT, the CIO's structural power, the CIO's level of strategic effectiveness, and a strong partnership between the CIO and top management team directly influence the CIO's level of strategic decision-making authority within the organization. The results also suggest that the CIO's strategic decision-making authority in the organization directly influences the contribution of IT to firm performance and that effective CIOs have a greater influence on IT's contribution when provided with strategic decision-making authority. [source] Comparison of continuous subcutaneous insulin infusion (CSII) and multiple daily injections (MDI) in paediatric Type 1 diabetes: a multicentre matched-pair cohort analysis over 3 yearsDIABETIC MEDICINE, Issue 1 2008B. I. Jakisch Abstract Aims To conduct a multicentre, matched-pair cohort analysis comparing glycaemic control and adverse events of continuous subcutaneous insulin infusion (CSII) with multiple daily injections (MDI) in paediatric patients. Methods Using standardized computer-based prospective documentation, HbA1c, insulin dose, body mass index,standard deviation score (BMI,SDS), rate of hypoglycaemia, rate of diabetic ketoacidosis (DKA) and intensity of care were analysed in 434 matched pairs during a follow-up period of 3 years after initiation of MDI or CSII. Results HbA1c was significantly lower in the CSII group during the first year of new regimen (CSII 7.5 ± 0.05 vs. MDI 7.7 ± 0.06; P < 0.05), but rose to the same level as in the MDI group during year 3. Insulin requirement remained significantly lower in the CSII group. The BMI,SDS increased in both study groups, with no significant difference. The rate of severe hypoglycaemia decreased significantly after the change of regimen (CSII 17.87 ± 2.85 vs. MDI 25.14 ± 3.79; P < 0.05) and during year 3 of the regimen, particularly when compared with baseline (,21% vs. ,16%). The rate of DKA was lower at baseline in the CSII group and remained significantly lower over all 3 years. Intensity of care was the same in both subsets. Conclusions Employing a large cohort, this matched-pair analysis has demonstrated over a 3-year study period that CSII is a safe form of intensive insulin therapy with similar glycaemic effects, but with significantly reduced rates of hypoglycaemia and DKA and a lower insulin requirement when compared with MDI. [source] Genetic and environmental interactions on oral cancer in Southern ThailandENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 2 2001Suparp Kietthubthew Abstract Many countries are interested in understanding the relationship between genetic susceptibility and their prevalent environmental cancers for disease prevention. In Thailand we conducted a population-based case-control study of 53 matched pairs to assess the risk of oral cancer in relation to genetic polymorphism of the glutathione-S-transferase genes (GSTM1 and GSTT1) in cigarette smokers, alcohol drinkers, and betel quid chewers. Interaction of the genes with other potential risk factors such as local bean consumption were also elucidated. Homozygous deletion of GSTM1 has a frequency of 56.6% (n = 30 over 53) among the patients and 30.2% (16/53) among the controls. This gene is associated with a 2.6-fold higher risk for development of oral cancer (95% CI 1.04,6.5). Among the null GSTM1 individuals, those who smoke, consume alcohol, and/or chew betel quid have a significantly increased risk for oral cancer with an odd ratio (OR) = 4.0 (95% CI = 1.2,13.7), OR = 7.2 (95% CI = 1.5,33.8), and OR = 4.4 (95% CI = 1.1,17.8), respectively. Interactions between any two of the lifestyle habits for oral cancer risk, however, are not found. The frequency of the GSTT1 null genotype is 34.0% (18/53) among the patients and 47.2% (25/53) among our controls. There is no association between the GSTT1 null allele and oral cancer risk. In conclusion, our study provides data to indicate that individuals who have homozygous deletion of the GSTM1 gene have increased risk for oral cancer. The risk increases further when these individuals are exposed to environmental toxicants such as chemicals in cigarette smoke, alcohol, and betel quid. These baseline data can be applied to a larger population-based study, both to verify the observation and to conduct mechanistic investigations. Environ. Mol. Mutagen. 37:111,116, 2001 © 2001 Wiley-Liss, Inc. [source] Gene expression analysis in absence epilepsy using a monozygotic twin designEPILEPSIA, Issue 9 2008Ingo Helbig Summary Purpose: To identify genes involved in idiopathic absence epilepsies by analyzing gene expression using a monozygotic (MZ) twin design. Methods: Genome-wide gene expression in lymphoblastoid cell lines (LCLs) was determined using microarrays derived from five discordant and four concordant MZ twin pairs with idiopathic absence epilepsies and five unaffected MZ twin pairs. Gene expression was analyzed using three strategies: discordant MZ twins were compared as matched pairs, MZ twins concordant for epilepsy were compared to control MZ twins, and a singleton design of affected versus unaffected MZ twin individuals was used irrespective of twin pairing. An overlapping gene list was generated from these analyses. Dysregulation of genes recognized from the microarray experiment was validated using quantitative real time PCR (qRT-PCR) in the twin sample and in an independent sample of 18 sporadic absence cases and 24 healthy controls. Results: Sixty-five probe sets were identified from the three combined microarray analysis strategies. Sixteen genes were chosen for validation and nine of these genes confirmed by qRT-PCR in the twin sample. Differential expression for EGR1 (an immediate early gene) and RCN2 (coding for the calcium-binding protein Reticulocalbin 2) were reconfirmed by qRT-PCR in the independent sample. Discussion: Using a unique sample of discordant MZ twins, our study identified genes with altered expression, which suggests novel mechanisms in idiopathic absence epilepsy. Dysregulation of EGR1 and RCN2 is implicated in idiopathic absence epilepsy. [source] Neural network approach to stereoscopic correspondence of three-dimensional particle tracking velocimetryIEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING, Issue 6 2008Achyut Sapkota Student Member Abstract Particle tracking velocimetry (PTV) is a reliable measurement technique for the quantitative study of fluid flows by observing the motion of the particles seeded in them and is widely used in several industrial applications. The nature of the flow can be precisely observed only if all the three components of the velocity are computed. In 3-D PTV system, particles viewed by two (or more than two) stereoscopic cameras with a parallax have to be correctly paired at every synchronized time step. This is important because the 3-D coordinates of individual particles cannot be computed without the knowledge of the correct stereo correspondence of the particles. In the present work, a neural network,based algorithm has been proposed for the stereoscopic particle pairing process. The correspondence between the particle pairs is modeled as a constrained optimization problem. The constraints are provided on the basis of the epipolar geometry of the particle images and on the basis of the uniqueness of the matched pairs. The results are tested with various standard images. Copyright © 2008 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source] Does the method of data collection affect patients' evaluations of quality of care?INTERNATIONAL JOURNAL OF NURSING PRACTICE, Issue 6 2000Bodil Wilde Larsson RNT The aim of the study was to compare two methods of data collection,personal interviews and self-administered questionnaires,with patients' evaluations of the quality of care they received. The sample consisted of 41 matched pairs of inpatients at a medical clinic. In each pair, one patient was interviewed and one responded to a questionnaire. Data were collected using the questionnaire ,Quality from the Patients Perspective' (QPP). The QPP consists of 54 items designed to measure the following four quality dimensions: (i) the medical,technical competence and (ii) the degree of identityorientation in the action of the caregivers; (iii) the physical,technical conditions; and (iv) the sociocultural atmosphere of the care organization. Results showed that patients who were interviewed had significantly less favourable scores on the ,softer' quality dimension scales,the identity-oriented approach of the caregivers and the sociocultural atmosphere of the care setting. Possible reasons for this were discussed, including the possibility that the questions designed to measure these two dimensions were more abstract and emotionally loaded than the items of the other two quality dimensions. [source] Reduction in Fear of Falling Through Intense Tai Chi Exercise Training in Older, Transitionally Frail AdultsJOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 7 2005Richard W. Sattin MD Objectives: To determine whether an intense tai chi exercise program could reduce fear of falling better than a wellness education (WE) program in older adults who had fallen previously and meet criteria for transitioning to frailty. Design: Cluster-randomized, controlled trial of 48 weeks' duration. Setting: Ten matched pairs of congregate living facilities in the greater Atlanta area. Participants: Sample of 291 women and 20 men, aged 70 to 97. Measurements: Activity-related fear of falling using the Activities-Specific Balance Confidence Scale (ABC) and the Fall Efficacy Scale at baseline and every 4 months for 1 year. Demographics, time to first fall and all subsequent falls, functional measures, Centers for Epidemiologic Studies Depression Scale, medication use, level of physical activity, comorbidities, and adherence to interventions. Results: Mean ABC was similar in both cohort groups at the time of randomization but became significantly higher (decreased fear) in the tai chi cohort at 8 months (57.9 vs 49.0, P<.001) and at study end (59.2 vs 47.9, P<.001). After adjusting for covariates, the mean ABC after 12 months of intervention was significantly greater in the tai chi group than in the WE group, with the differences increasing with time (mean difference at 12 months=9.5 points, 95% confidence interval=4.8,14.2, P<.001). Conclusion: Tai chi led to a significantly greater reduction in fear of falling than a WE program in transitionally frail older adults. The mean percentage change in ABC scores widened between tai chi and WE participants over the trial period. Tai chi should be considered in any program designed to reduce falling and fear of falling in transitionally frail older adults. [source] Testing biotic indicator taxa: the sensitivity of insectivorous mammals and their prey to the intensification of lowland agricultureJOURNAL OF APPLIED ECOLOGY, Issue 1 2008Michael J. O. Pocock Summary 1Changes to agricultural policy aim to extensify agriculture and increase biodiversity. However, it is not known how sensitive many taxa are to intensification. Sensitive taxa could be used as biotic indicators, to assess changes over time and the effectiveness of policy changes. 2We sampled shrews, bats and their prey (beetles, flies and moths) on matched pairs of sites and assessed the response in their abundance to aspects of intensification: increased agrochemical inputs (using abundance on matched organic and conventional cereal fields as a proxy), the switch from hay to silage (using abundance on matched hay and silage fields) and boundary loss (using abundance in the field and near the boundary as a proxy, in cereal and grass separately). We quantified the abundance-derived sensitivity of the taxa in order to assess their use as biotic indicators. 3There was substantial variation in the sensitivity of taxa to the three aspects of intensification. Most estimates (51%) of sensitivity to boundary loss were significant, but only 8% for increased agrochemical inputs and 16% for the switch from hay to silage. Sensitivity to one aspect of intensification was not significantly related to sensitivity to another. 4Insectivorous mammals were relatively insensitive to increased agrochemical inputs and the switch from hay to silage, but strongly sensitive to boundary loss. 5Taxa with significant sensitivity to increased agrochemical inputs included some Carabidae and Diptera. We found fewer significant differences in abundance between organic and conventional farms than previous workers, probably because we controlled for boundary characteristics, suggesting that the quality of field boundaries is important in influencing biodiversity differences between organic and conventional farms. 6The switch from hay to silage had a positive effect on some Coleoptera and Diptera but a substantial negative effect on Hepialidae (Lepidoptera). 7Synthesis and applications. The recorded sensitivity of taxa to changes in agricultural practices is highly variable. Therefore, the selection of biotic indicator taxa of agricultural intensification is not straightforward. If surveys of biotic indicator taxa are used to assess the effectiveness of changes in agricultural practice, empirical evidence should be used to select suitable taxa. [source] Effects of academic stress on oral hygiene , a potential link between stress and plaque-associated disease?JOURNAL OF CLINICAL PERIODONTOLOGY, Issue 5 2001Renate Deinzer Abstract Background: While there seems to be a common belief that psychosocial stress affects oral hygiene behavior, this assumption has rarely been proved. The present study thus aims to analyse stress effects on oral hygiene. Material and Methods: 16 matched pairs of medical students each consisting of 1 student participating in a major academic exam and 1 control without current academic stress, were formed on the basis of baseline plaque levels. At baseline, a professional tooth cleaning was performed. On the last day of exams, students answered questionnaires about oral hygiene during the exams and were afterwards asked to attend for a 2nd dental examination, of which they had no prior knowledge. Results: On the last day of exams, approximately 6 weeks after professional tooth cleaning, 20.9±18.3% of control students' sites but only 10.5±9.3% of exam students' sites were found to be free of any plaque (p=0.022). Differences were most obvious at oral, as compared to vestibular, sites. Exam students reported a reduction in thoroughness (p=0.019) but not of frequency of oral hygiene behavior. Conclusion: The study strongly supports the assumption that psychosocial stress may induce neglect of oral hygiene and increase of plaque accumulation. Zusammenfassung Hintergrund: Obwohl es eine allgemeine Annahme zu sein scheint, daß psycho-sozialer Stress die Mundhygiene beeinflußt, ist diese Annahme bisher selten geprüft worden. Mit der gegenwärtigen Studie sollen deshalb Stresseffekte auf die Mundhygiene analysiert werden. Material und Methoden. 16 gematchte Paare von Medizinstudenten, von denen jedes aus einem Student, der an einem wichtigen akademischen Examen teilnahm, und einer Kontrolle ohne gegenwärtigen akademischen Stress bestand, wurden auf der Basis von Baseline Plaquewerten gebildet. Zur Baseline wurde eine professionelle Zahnreinigung durchgeführt. Zum letzten Tag der Examen beantworteten die Studenten Fragebögen über die Mundhygiene während des Examens und wurde danach zu einer zweiten zahnärztlichen Überprüfung aufgefordert, von der sie zuvor keine Kenntnis hatten. Ergebnisse: Am letzten Tag des Examens ungefähr 6 Wochen nach der professionellen Zahnreinigung waren 20.9%±18.3% der Flächen der Kontrollstudenten, aber nur 10.5%±9.3% der Flächen der Examensstudenten plaquefrei (p=0.022). Die Differenzen waren an den oralen Flächen am deutlichsten, verglichen mit den vestibulären Flächen. Die Examensstudenten berichteten über eine Reduktion in der Gründlichkeit (p=0.019), aber nicht in der Häufigkeit der oralen Hygiene. Schlußfolgerung: Die Studie unterstützt nachhaltig die Annahme, daß psycho-sozialer Stress eine Vernachlässigung der oralen Hygiene und eine Zunahme der Plaqueakkumulation induziert. Résumé Bien que l'idée qu'un psycho-asocial puisse affecter les habitudes d'hygiène buccale, celle-ci n'a que rarement été prouvée. L'étude présente a donc analysé les effets du stress sur l'hygiène buccale. 16 paires d'étudiants en médicine dont l'un des deux participait à un examen académique majeur ont été formés sur base du niveau de plaque dentaire lors de l'examen initial. Lors de cet examen, un nettoyage professionnel a été effectué. Le dernier jour des examens les étudaints répondaient à des questionnaires à propos de leur hygiène buccale durant les examens et ont ensuite été réexaminés, ce dont ils n'avaint pas été informés précédement. Le dernier jour des examens, environ 6 semaines après le nettoyage professionnel, 21±18% des sites contrôles mais aussi 11±9% des sites des étudiants en examen n'avaient pas de trace de plaque dentaire (p=0.022). Les différenes les plus visibles se situaient au niveau lingual comparé aux sites vestibulaires. Chaque étudiant avait une réduction dans la qualité (p=0.019) mais non dans la fréquence de l'habitude d'hygiène buccale. Cette étude soutient grandement l'idée que le stress psychosocial engendre une négligence de l'hygiène buccale et augmente ainsi l'accumulation de plaque dentaire. [source] Obesity in adults with Down syndrome: a case,control studyJOURNAL OF INTELLECTUAL DISABILITY RESEARCH, Issue 2 2005C. A. Melville Abstract Background Obesity has a negative impact upon mortality and morbidity. Studies report that obesity is more prevalent in individuals with Down syndrome than individuals with intellectual disabilities (ID) not associated with Down syndrome. However, there have been no studies using a methodology of matched comparison groups and findings from previous studies are contradictory. Methods A detailed method was used to identify all adults with ID in Leicestershire. Individuals were invited to participate in a medical examination , that included measurement of their height and weight, from which body mass index (BMI) was calculated. For each person with Down syndrome, an individual matched for gender, age and accommodation type was identified, from the Leicestershire ID database. Results The data for 247 matched pairs is reported. Women with Down syndrome had lower mean height and weight, but greater mean BMI than the matched pairs. Men with Down syndrome had a lower mean height and weight but there was no statistical difference in BMI compared to the matched pairs. Using World Health Organization categories of BMI, women with Down syndrome were more likely to be overweight or obese than their matched pairs (odds ratio = 2.17). Men with Down syndrome were more likely to be in the overweight category than their matched pairs but were less likely to be obese (odds ratio = 0.85). Conclusions This study demonstrates that, compared to a matched sample, there is a greater prevalence of obesity amongst women with Down syndrome but not men. As the impact on the health of people with Down syndrome of being overweight or obese is uncertain, this is an area that requires further study. [source] Work status and organizational citizenship behavior: a field study of restaurant employeesJOURNAL OF ORGANIZATIONAL BEHAVIOR, Issue 5 2001Christina L. Stamper This survey-based field study of 257 service employees developed and tested a model of differences in the organizational citizenship behavior of full-time and part-time employees based on social exchange theory. Questionnaire data from matched pairs of employees and their supervisors demonstrated that part-time employees exhibited less helping organizational citizenship behavior than full-time employees, but there was no difference in their voice behavior. We also predicted that both preferred work status (an individual factor) and organizational culture (a contextual factor) would moderate the relationships between work status and citizenship. For helping, results demonstrated that preferred status mattered more to part-time workers than to full-time. For voice, preferred work status was equally important to part-time and full-time workers, such that voice was high only when actual status matched preferred status. Contrary to our expectations, work status made more of a difference in both helping and voice in less bureaucratic organizations. We discuss the implications of work status for social exchange relationships, differences in the social exchange costs and benefits of helping compared to voice, and ramifications of our findings for future research. Copyright © 2001 John Wiley & Sons, Ltd. [source] EFFECT OF MILK PASTEURIZATION ON FLAVOR PROPERTIES OF SEVEN COMMERCIALLY AVAILABLE FRENCH CHEESE TYPESJOURNAL OF SENSORY STUDIES, Issue 4 2010DELORES H. CHAMBERS ABSTRACT Previous research on matched pairs of experimental cheese showed that heat treatment of milk affected flavor properties. However, whether pasteurization has a generalized effect or whether the effect is specific to certain cheese varieties is not known. Experienced, highly trained sensory panelists developed flavor profiles for seven commercially available French cheeses (Brie, Coulommier, Camembert, Saint Nectaire, Muenster, Chèvre and Bleu) for which versions made from pasteurized or unpasteurized milk were commercially available. Raw-milk cheese had stronger odor properties. Soft cheeses with white rind (Brie, Coulommier, Camembert and Saint Nectaire) as well as Chèvre and Bleu were affected similarly by heat treatment of milk, but the sensory characteristics of Muenster cheese did not follow the pattern of other cheeses. These results suggest that many, but not all, cheese types show similar changes in sensory attributes as a result of using pasteurized rather than raw milk. PRACTICAL APPLICATIONS This study gives manufacturers and researchers information on flavor differences that exist between similar cheese types made from raw or pasteurized milk. Researchers and manufacturers can use that information in order to develop pasteurized-milk cheese that has the traditional full-flavored characteristics of its raw-milk counterpart. [source] Differences among forced-air warming systems with upper body blankets are small.ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 9 2003A randomized trial for heat transfer in volunteers Background:, Forced-air warming is known as an effective procedure in prevention and treatment of perioperative hypothermia. Significant differences have been described between forced-air warming systems in combination with full body blankets. We investigated four forced-air warming systems in combination with upper body blankets for existing differences in heat transfer. Methods:, After approval of the local Ethics Committee and written informed consent, four forced-air warming systems combined with upper body blankets were investigated in a randomized cross-over trial on six healthy volunteers: (1) BairHuggerÔ 505 and Upper Body Blanket 520, Augustine Medical; (2) ThermaCareÔ TC 3003, GaymarÔ and OptisanÔ Upper Body Blanket, Brinkhaus; (3) WarmAirÔ 134 and FilteredFlowÔ Upper Body Blanket, CSZ; and (4) WarmTouchÔ 5800 and CareDrapeÔ Upper Body Blanket, Mallinckrodt. Heat transfer from the blanket to the body surface was measured with 11 calibrated heat flux transducers (HFTs) with integrated thermistors on the upper body. Additionally, the blanket temperature was measured 1 cm above the HFT. After a preparation time of 60 min measurements were started for 20 min. Mean values were calculated over 20 min. The t -test for matched pairs with Bonferroni-Holm-correcture for multiple testing was used for statistical evaluation at a P -level of 0.05. The values are presented as mean±SD. Results:, The WarmTouchÔ blower with the CareDrapeÔ blanket obtained the best heat flux (17.0±3.5 W). The BairHuggerÔ system gave the lowest heat transfer (8.1±1.1 W). The heat transfer of the ThermaCareÔ system and WarmAirÔ systems were intermediate with 14.3±2.1 W and 11.3±1.0 W. Conclusions:, Based on an estimated heat loss from the covered area of 38 W the heat balance is changed by 46.1 W to 55 W by forced-air warming systems with upper body blankets. Although the differences in heat transfer are significant, the clinical relevance of this difference is small. [source] Placental transfer of IgG subclasses in a Japanese populationPEDIATRICS INTERNATIONAL, Issue 4 2000Shintaro Hashira Abstract Background: Maternal immunoglobulin G (IgG), transferred across the placenta to the fetus during intrauterine life, is an important component of the neonatal immunological defence mechanisms against infection. There is controversy with respect to differences in placental transfer of the different IgG subclasses, and no definite data are available on a Japanese population. Therefore, we investigated placental transfer of IgG subclasses in a Japanese population. Methods: A total of 228 matched pairs of cord and maternal serum samples (20,42 weeks gestation) were assayed for each IgG subclass by an enzyme-linked immunosorbent assay. Results: The mean values and hierarchy of cord/maternal concentration ratios of IgG subclasses at 40 weeks gestation were as follows: IgGl(1.47)>IgG3(1.17)=IgG4(1.15)>IgG2(0.80). The cord/maternal concentration ratios of all IgG subclasses were positively correlated to gestational age. The mean ratios for IgG1 and IgG4 nearly reached a plateau at 39 and 37 weeks gestation, respectively, while those for IgG2 and IgG3 increased until 41 weeks gestation. The ratios of all IgG subclasses for full-term deliveries were reciprocally correlated to the respective maternal IgG subclass serum levels. Conclusions: The results suggest that although all four IgG subclasses are actively transferred across the placenta, the efficiency of their transfer ranks in the order IgGl >IgG3=IgG4>IgG2. The different results as to placental transfer of IgG subclasses in the literature might be due, at least in part, to different maternal IgG subclass serum levels in the populations studied. [source] Computer-assisted tibia preparation for total ankle arthroplasty: a cadaveric studyTHE INTERNATIONAL JOURNAL OF MEDICAL ROBOTICS AND COMPUTER ASSISTED SURGERY, Issue 4 2007Samuel B. Adams Jr Abstract Background Most surgeons performing total ankle arthroplasty (TAA) suggest that accurate tibial preparation perpendicular to the tibial shaft axis improves outcomes. Recent studies demonstrate that computerized surgical navigation significantly improves the accuracy of tibial preparation in total knee arthroplasty (TKA). Methods We performed the tibial preparation for TAA in seven matched pairs of cadaver lower extremities. One set of matched pairs was prepared using the conventional external tibial alignment guide/cutting block from the Scandanavian Total Ankle Replacement system (STAR, Waldemar Link GmbH & Co., Hamburg, Germany) under fluoroscopic guidance. The second set of matched pairs was prepared using the VectorVision® navigation system (BrainLAB, Munich, Germany), with currently available computed tomography (CT)-based TKA software. Pre-operative CT data were used to assess the tibial mechanical axis. In both groups, accuracy of the tibial plafond preparation relative to the tibial shaft axis in both the coronal and sagittal planes was determined by fluoroscopic, radiographic and CT analysis. Results Mean values of the tibial cut for the set of matched-pair tibiae prepared by the conventional surgical method ranged across the three imaging assessment techniques in the ranges 89.3,89.6° (coronal plane, anteroposterior) and 90.3,90.4° (sagittal plane, lateral). For the computer-navigated set, the values were 89.7,89.9° (coronal) and 89.1,89.4° (sagittal). Comparison between the conventional and computer-navigated tibial measurements were not different at the 95% confidence interval (CI) for CT, fluoroscopy or radiographic assessments. Conclusions Our results demonstrate that accuracy of TAA tibial preparation using computer-navigation equals that of the conventional technique performed by a foot and ankle surgeon experienced in TAA. We anticipate that this investigation will encourage the development of computer-navigation applications specific to TAA, with the potential of improving accuracy over conventional methods. Copyright © 2008 John Wiley & Sons, Ltd. [source] Is reversal of large stock-price declines caused by overreaction or information asymmetry: Evidence from stock and option marketsTHE JOURNAL OF FUTURES MARKETS, Issue 4 2009Hyung-Suk Choi The role of option markets is reexamined in the reversal process of stock prices following stock price declines of 10% or more. A matched pair of optionable and nonoptionable firms is randomly selected when their price declines by 10% or more on the same date. The authors examine the 1,443 and 1,018 matched pairs of New York Stock Exchange/American Stock Exchange (AMEX) and National Association of Securities Dealers Automated Quotations firms over the period from 1996 to 2004. It was found that the positive rebounds for nonoptionable firms are caused by an abnormal increase in bid,ask spread on and before the large price decline date. On the other hand, the bid,ask spreads for optionable firms decrease on and before the large price decline date. An abnormal increase in the open interest and volume in the option market on and before the large price decline date was also found. Overall, the results suggest that the stock-price reversal neither is a result of overreaction nor can it be simply explained by the bid,ask bounce. © 2009 Wiley Periodicals, Inc. Jrl Fut Mark 29:348,376, 2009 [source] Racial Differences in Stage and Survival in Head and Neck Squamous Cell Carcinoma,THE LARYNGOSCOPE, Issue 5 2007Anthony C. Nichols MD Abstract Objectives: The goal of this study was to characterize differences in survival between black patients and white patients with squamous cell carcinoma of the head and neck (HNSCCA). Design: Cases of oral tongue and glottic SCCA in black patients or white patients were extracted from the Surveillance, Epidemiology, and End Results (SEER) database (years 1988,2002). For each primary site, TNM staging was imputed, and staging distributions were compared between races. For each black patient, a randomly selected white control was matched for age at diagnosis, sex, stage, surgical treatment, and radiation. Kaplan-Meier survival comparisons for both overall and disease-specific survival were then conducted for the matched pairs. Results: From 1,919 cases of carcinoma of the oral tongue, those of 151 black and 1,768 white patients were extracted. Black patients had a significantly elevated T stage (P = .001) and N stage (P = .002) at primary presentation. Of glottic carcinoma, 4,578 cases (625 black and 3,953 white patients) were extracted. Black patients again presented with significantly elevated T stage (P < .001) and N stage (P < .001) compared with white patients. For 43 matched pairs with tongue carcinoma, mean overall survival for black patients was 66.1 months versus 74.8 months for matched white controls (P = .502, log-rank test). Disease-specific survival was 91.1 months for black patients versus 109.6 months for white patients (P = .168). For 401 matched pairs with glottic carcinoma, mean overall survival for black patients was 96.6 months versus 114.5 months for white controls (P < .001). Similarly, the mean disease-specific survival was 149.4 months for black patients versus 167.1 months for white patients (P < .001) Conclusion: Controlling for stage and treatment, black patients demonstrate poorer overall and disease-specific survival with SCCA, implying other intrinsic or extrinsic factors influencing survival. [source] Exact, Distribution Free Confidence Intervals for Late Effects in Censored Matched PairsBIOMETRICAL JOURNAL, Issue 1 2009Shoshana R. Daniel Abstract When comparing censored survival times for matched treated and control subjects, a late effect on survival is one that does not begin to appear until some time has passed. In a study of provider specialty in the treatment of ovarian cancer, a late divergence in the Kaplan,Meier survival curves hinted at superior survival among patients of gynecological oncologists, who employ chemotherapy less intensively, when compared to patients of medical oncologists, who employ chemotherapy more intensively; we ask whether this late divergence should be taken seriously. Specifically, we develop exact, permutation tests, and exact confidence intervals formed by inverting the tests, for late effects in matched pairs subject to random but heterogeneous censoring. Unlike other exact confidence intervals with censored data, the proposed intervals do not require knowledge of censoring times for patients who die. Exact distributions are consequences of two results about signs, signed ranks, and their conditional independence properties. One test, the late effects sign test, has the binomial distribution; the other, the late effects signed rank test, uses nonstandard ranks but nonetheless has the same exact distribution as Wilcoxon's signed rank test. A simulation shows that the late effects signed rank test has substantially more power to detect late effects than do conventional tests. The confidence statement provides information about both the timing and magnitude of late effects (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | |||||||||||||||||||