Home About us Contact
|
Home About us Contact | ||
|
|
||
Practical Significance (practical + significance)
Selected AbstractsNMR studies of surfactantsCONCEPTS IN MAGNETIC RESONANCE, Issue 2 2004Olle Söderman Abstract Surfactant molecules are amphipathic and posses complicated solution chemistry and self-assembly properties. In addition to being of enormous practical significance, the physical characterization of surfactant systems presents a rich area of condensed matter physics. This article focuses on the application and interpretation of the commonly used NMR approaches for probing these systems. In particular, the use of NMR relaxation, diffusometry and, more briefly, electrophoretic NMR to determine characteristics such as micellar size and structure, ion-binding and solubilization are considered. The application of these NMR techniques is illustrated by a number of pertinent examples. © 2004 Wiley Periodicals, Inc. Concepts Magn Reson 23A:, 121,135, 2004. [source] The eigenvalues of isolated bridges with transverse restraints at the end abutmentsEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 8 2010Nicos Makris Abstract This paper examines the eigenvalues of multi-span seismically isolated bridges in which the transverse displacement of the deck at the end abutments is restricted. With this constraint the deck is fully isolated along the longitudinal direction, whereas along the transverse direction the deck is a simple-supported beam at the end abutments which enjoys concentrated restoring forces from the isolation bearings at the center piers. For moderate long bridges, the first natural period of the bridge is the first longitudinal period, while the first transverse period is the second period, given that the flexural rigidity of the deck along the transverse direction shortens the isolation period offered by the bearings in that direction. This paper shows that for isolated bridges longer than a certain critical length, the first transverse period becomes longer than the first longitudinal period despite the presence of the flexural rigidity of the deck. This critical length depends on whether the bridge is isolated on elastomeric bearings or on spherical sliding bearings. This result is also predicted with established commercially available numerical codes only when several additional nodes are added along the beam elements which are modeling the deck in-between the bridge piers. On the other hand, this result cannot be captured with the limiting idealization of a beam on continuous distributed springs (beam on Wrinkler foundation),a finding that has practical significance in design and system identification studies. Finally, the paper shows that the normalized transverse eigenperiods of any finite-span deck are self-similar solutions that can be represented by a single master curve and are independent of the longitudinal isolation period or on whether the deck is supported on elastomeric or spherical sliding bearings. Copyright © 2009 John Wiley & Sons, Ltd. [source] Prevention programs in the 21st century: what we do not discuss in publicADDICTION, Issue 4 2010Harold Holder ABSTRACT Prevention research concerning alcohol, tobacco and other drugs faces a number of challenges as the scientific foundation is strengthened for the future. Seven issues which the prevention research field should address are discussed: lack of transparency in analyses of prevention program outcomes, lack of disclosure of copyright and potential for profit/income during publication, post-hoc outcome variable selection and reporting only outcomes which show positive and statistical significance at any follow-up point, tendency to evaluate statistical significance only rather than practical significance as well, problem of selection bias in terms of selecting subjects and limited generalizability, the need for confirmation of outcomes in which only self-report data are used and selection of appropriate statistical distributions in conducting significance testing. In order to establish a solid scientific base for alcohol, tobacco and drug prevention, this paper calls for discussions, disclosures and debates about the above issues (and others) as essential. In summary, the best approach is always transparency. [source] Nonlinear Smoluchowski velocity for electroosmosis of Power-law fluids over a surface with arbitrary zeta potentialsELECTROPHORESIS, Issue 5 2010Cunlu Zhao Abstract Electroosmotic flow of Power-law fluids over a surface with arbitrary zeta potentials is analyzed. The governing equations including the nonlinear Poisson,Boltzmann equation, the Cauchy momentum equation and the continuity equation are solved to seek exact solutions for the electroosmotic velocity, shear stress, and dynamic viscosity distributions inside the electric double layer. Specifically, an expression for the general Smoluchowski velocity is obtained for electroosmosis of Power-law fluids in a fashion similar to the classic Smoluchowski velocity for Newtonian fluids. The existing Smoluchowski slip velocities under two special cases, (i) for Newtonian fluids with arbitrary zeta potentials and (ii) for Power-law fluids with small zeta potentials, can be recovered from our derived formula. It is interesting to note that the general Smoluchowski velocity for non-Newtonian Power-law fluids is a nonlinear function of the electric field strength and surface zeta potentials; this is due to the coupling electrostatics and non-Newtonian fluid behavior, which is different from its counterpart for Newtonian fluids. This general Smoluchowski velocity is of practical significance in determining the flow rates in microfluidic devices involving non-Newtonian Power-law fluids. [source] Natural polyphenols as chain-breaking antioxidants during methyl linoleate peroxidationEUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 8 2010Ivan Tichonov Abstract A technique based on monitoring oxygen consumption was applied to study 11 natural and model polyphenols (PP, QH2) as well as four typical monophenolics as a chain-breaking antioxidant during the controlled chain oxidation of methyl linoleate (ML) in bulk at 37°C. The antioxidant activities of QH2 were characterized by two parameters: the rate constant k1 for reaction of QH2 with the peroxy radical : (i) QH2,+,,,,,+,LOOH and the stoichiometric factor of inhibition, f, which shows how many kinetic chains may be terminated by one molecule of QH2. The rate constant k1 were reduced significantly by factor of 4 ,28 as compared to these determined during the oxidation of styrene in bulk; the effect was typically more pronounced for catechol derivatives than for pyrogallol derivatives. At the same time, f for QH2 was found to be close to two independent of the number of active OH groups, similar to that determined earlier during the inhibited oxidation of styrene. The formation of H bond between OH group of QH2 and carboxyl group of ML is suggested as a reason for reducing effect of ML on k1. Practical applications: This work reports rate constants for the reaction of lipid peroxyl radical with phenolics and stoichiometric coefficient of inhibition, which characterize the antioxidant activity (AOA) of 15 natural and model PP, QH2 during the controlled peroxidation of ML. The reactivity of PP, QH2 during the oxidation of ML is routinely lower than the reactivity during the oxidation of non-polar model hydrocarbons. This information may be useful to estimate the AOA of natural PP, QH2 in real systems of practical significance including plant oils, fats, food-stuffs, biological objects, and similar. [source] Aerobic exercise training reduces hepatic and visceral lipids in obese individuals without weight loss,HEPATOLOGY, Issue 4 2009Nathan A. Johnson Weight loss remains the most common therapy advocated for reducing hepatic lipid in obesity and nonalcoholic fatty liver disease. Yet, reduction of body weight by lifestyle intervention is often modest, and thus, therapies which effectively modulate the burden of fatty liver but are not contingent upon weight loss are of the highest practical significance. However, the effect of aerobic exercise on liver fat independent of weight loss has not been clarified. We assessed the effect of aerobic exercise training on hepatic, blood, abdominal and muscle lipids in 19 sedentary obese men and women using magnetic resonance imaging and proton magnetic resonance spectroscopy (1H-MRS). Four weeks of aerobic cycling exercise, in accordance with current physical activity guidelines, significantly reduced visceral adipose tissue volume by 12% (P < 0.01) and hepatic triglyceride concentration by 21% (P < 0.05). This was associated with a significant (14%) reduction in plasma free fatty acids (P < 0.05). Exercise training did not alter body weight, vastus lateralis intramyocellular triglyceride concentration, abdominal subcutaneous adipose tissue volume, 1H-MRS,measured hepatic lipid saturation, or HOMA-IR (homeostasis model assessment of insulin resistance; P > 0.05). Conclusion: These data provide the first direct experimental evidence demonstrating that regular aerobic exercise reduces hepatic lipids in obesity even in the absence of body weight reduction. Physical activity should be strongly promoted for the management of fatty liver, the benefits of which are not exclusively contingent upon weight loss. (HEPATOLOGY 2009.) [source] Numerical error patterns for a scheme with hermite interpolation for 1 + 1 linear wave equationsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 5 2004Zuojin Zhu Abstract Numerical error patterns were presented when the fourth-order scheme based on Hermite interpolation was used to solve the 1 + 1 linear wave equation. Since most non-linear equations for real systems can be converted into linear forms by using proper transformations, this study certainly pertains its practical significance. The analytical solution was obtained under inhomogeneous initial and boundary conditions. It was found that not only the Hurst index of an error train at a given position but also its spatial distribution is dependent on the ratio of temporal to spatial intervals. The solution process with the fourth-order scheme based on Hermite interpolation diverges as the ratio is greater than unity. The results show that regular error pattern and smaller maxima of absolute values of numerical errors can be obtained when the ratio is set as unity; while chaotic phenomena for the numerical error propagation process can appear when the ratio is less than unity. It was found that it is better to choose the ratio as unity for the numerical solution of 1 + 1 linear wave equation with the scheme; while other selections for the ratio in the scheme can bring about chaotic patterns for the numerical errors. Copyright © 2004 John Wiley & Sons, Ltd. [source] Theoretical basis for extraction of mildly nonlinear behavioral modelsINTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 1 2003José C. Pedro Abstract The analytical and laboratory requirements for the extraction of a mildly nonlinear behavioral model are derived. This shows that they greatly exceed current capabilities in general, and a simplified procedure based on dynamic linear element deembedding is proposed. This procedure is then illustrated for a case of practical significance by discussing various methods to extract an intermodulation model of a MES field effect transistor. © 2003 Wiley Periodicals, Inc. Int J RF and Microwave CAE 13: 40,53, 2003. [source] Justice Expectations and Applicant PerceptionsINTERNATIONAL JOURNAL OF SELECTION AND ASSESSMENT, Issue 1-2 2004Bradford S. Bell Expectations, which are beliefs about a future state of affairs, constitute a basic psychological mechanism that underlies virtually all human behavior. Although expectations serve as a central component in many theories of organizational behavior, they have received limited attention in the organizational justice literature. The goal of this paper is to introduce the concept of justice expectations and explore its implications for understanding applicant perceptions. To conceptualize justice expectations, we draw on research on expectations conducted in multiple disciplines. We discuss the three sources of expectations , direct experience, indirect influences, and other beliefs , and use this typology to identify the likely antecedents of justice expectations in selection contexts. We also discuss the impact of expectations on attitudes, cognitions, and behaviors, focusing specifically on outcomes tied to selection environments. Finally, we explore the theoretical implications of incorporating expectations into research on applicant perceptions and discuss the practical significance of justice expectations in selection contexts. [source] Promiscuous Zinc-Dependent Acylase-Mediated One-Pot Synthesis of Monosaccharide-Containing Pyrimidine Derivatives in Organic MediumADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2009Qi Wu Abstract A facile one-pot synthesis route to monosaccharide-containing pyrimidine derivatives was developed by combining the two types of catalytic activities of one enzyme in an organic medium, i.e., the Michael addition/acylation activities of zinc-dependent D -aminoacylase (DA) from Escherichia coli. First, the stepwise approach was investigated. DA showed higher activity towards the Michael addition than acylation in this reaction system. The enzymatic Michael additions of pyrimidines to vinyl acrylate proceeded very rapidly and the initial reaction rates for the Michael addition of pyrimidines to vinyl acrylate were 7.2,16.5,mM,min,1. The catalytic specificity of aminoacylases toward Michael addition was demonstrated by the combination of different control experiments. Then, the two steps could be performed in one pot and a single aminoacylase catalyzed one-pot biotransformation was constructed. Using this strategy, a series of saccharide-pyrimidine complexes with potentially biological and pharmacological applications was prepared efficiently. This high Michael addition activity of zinc-dependent aminoacylases and the novel single aminoacylase-catalyzed one-pot synthesis combining two catalytic activities in vitro is of practical significance in expanding the application of enzymes and in the evolution of new biocatalysts. [source] Responses of milk production to the intravenous infusion of amino acids in dairy cows given diets of grass silage and cereal-based supplementsJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 9-10 2001C.-H. Kim Three experiments were carried out to examine responses of milk production to the intravenous infusion of amino acids in dairy cows given diets of grass silage and supplements based on barley, with or without added soyabean meal and ranging in crude protein content from 16 to 19% in dry matter. Particular attention was given to histidine, administered alone or in combination with methionine, lysine and tryptophan. Responses of milk protein secretion to infusion of histidine were seen only when the diet contained a supplement of barley alone. When soyabean meal was included, there were no responses of milk production to infusion of any of the infused amino acids. Calculations suggested that, although histidine remained first-limiting when soya was included in the diet, any response to infusion of histidine was blocked by the rapidly emerging deficiency of another amino acid, probably leucine. The results confirm that, for diets based on grass silage and supplements of cereal only, histidine is first-limiting such that increases of milk protein secretion can be obtained in response to infusion of histidine alone. In assessing the practical significance of this finding, it should be remembered that greater responses in the yield of milk protein can probably be obtained by substituting 1 kg of soyabean meal for 1 kg of cereal, which is likely to be an easier and cheaper option. [source] Minireview: does in-vitro testing of oximes help predict their in-vivo action after paraoxon exposure?JOURNAL OF APPLIED TOXICOLOGY, Issue 6 2009D. E. Lorke Abstract K-oximes have recently been developed in the search for efficacious broad-band reactivators of acetylcholinesterase (AChE) inhibited by organophosphorus compounds (OPC). Before clinical use, their toxicity and efficacy need to be assessed, and there is clear demand for simple in vitro tests that can predict in vivo performance. This article summarizes our in vitro data obtained for conventional and experimental oximes in human and rat blood exposed to the OPC paraoxon and correlates them with our in vivo results. The intrinsic AChE inhibitory activity of oximes, as reflected by their in vitro IC50, is strongly correlated with their LD50 (rat): oximes with a high IC50 (K-27, K-48, pralidoxime and obidoxime) also show a high LD50 and are thus relatively non-toxic, whereas oximes K-105, K-108 and K-113 have a low IC50, a low LD50 and are far more toxic. The IC50 is also correlated with the in vivo capacity to protect from paraoxon-induced mortality: oximes with a higher IC50 reduce the relative risk of death more. In contrast, the protective ability as assessed in vitro by the slope of the IC50 shift (tan,), is not correlated with in vivo protection from paraoxon-induced mortality: the best in vivo protectors (K-27 and K-48) show a much lower tan, value (around 2) than K-110 and K-113 (tan, around 10), which hardly reduce the relative risk of death after paraoxon exposure. The partition coefficient logP of the individual oximes is inversely correlated with their IC50 and with their LD50 and is therefore an indicator of toxicity: strongly hydrophilic oximes tend to be less toxic than less hydrophilic ones. These data highlight the good predictive value of in vitro IC50 testing for in vivo toxicity and the limited practical significance of in vitro assessment of protective potency. Copyright © 2009 John Wiley & Sons, Ltd. [source] Clouds make nerds look good: field evidence of the impact of incidental factors on decision makingJOURNAL OF BEHAVIORAL DECISION MAKING, Issue 2 2007Uri SimonsohnArticle first published online: 9 OCT 200 Abstract Abundant experimental research has documented that incidental primes and emotions are capable of influencing people's judgments and choices. This paper examines whether the influence of such incidental factors is large enough to be observable in the field, by analyzing 682 actual university admission decisions. As predicted, applicants' academic attributes are weighted more heavily on cloudier days and non-academic attributes on sunnier days. The documented effects are of both statistical and practical significance: changes in cloud cover can increase a candidate's predicted probability of admission by an average of up to 11.9%. These results also shed light on the causes behind the long demonstrated unreliability of experts making repeated judgments from the same data. Copyright © 2006 John Wiley & Sons, Ltd. [source] Exact Small-Sample Differential Item Functioning Methods for Polytomous Items With Illustration Based on an Attitude SurveyJOURNAL OF EDUCATIONAL MEASUREMENT, Issue 4 2004J. Patrick Meyer Exact nonparametric procedures have been used to identify the level of differential item functioning (DIF) in binary items. This study explored the use of exact DIF procedures with items scored on a Likert scale. The results from an attitude survey suggest that the large-sample Cochran-Mantel-Haenszel (CMH) procedure identifies more items as statistically significant than two comparable exact nonparametric methods. This finding is consistent with previous findings; however, when items are classified in National Assessment of Educational Progress DIF categories, the results show that the CMH and its exact nonparametric counterparts produce almost identical classifications. Since DIF is often evaluated in terms of statistical and practical significance, this study provides evidence that the large-sample CMH procedure may be safely used even when the focal group has as few as 76 cases. [source] Facial Soft Tissue Thicknesses in Australian Adult Cadavers,JOURNAL OF FORENSIC SCIENCES, Issue 1 2006Monica Domaracki B.Sc. ABSTRACT: Craniofacial identification methods heavily rely on the knowledge of average soft tissue depths. This study measured soft tissue thicknesses of an Australian cadaver sample (N=33) using published needle puncture techniques at 13 anatomical locations. Data were compared and contrasted with other studies that used essentially identical samples and methods. Full descriptive statistics were calculated for measurements made in this study and means, medians, and modes were reported. Differences between mean values for males and females were found to be minimal (2.2 mm or less) and considerable overlap was found between the groups. There were no statistically significant differences between the soft tissue depths of the sexes (P>0.05). These findings indicate that differences between male and female soft tissue depths are of little practical significance for craniofacial identification and, therefore, data (means, standard deviations, and sample sizes) reported for Australians were pooled across the sexes and the studies. Although these new pooled means have increased statistical power, data distributions at some landmarks were skewed and thus emphasis is placed on median and modes reported for this study rather than upon the collapsed data means. [source] Spatial patterns of Indian serial burglars with relevance to geographical profilingJOURNAL OF INVESTIGATIVE PSYCHOLOGY AND OFFENDER PROFILING, Issue 2 2006Sudhanshu Sarangi Abstract Earlier studies in Western countries have shown remarkably consistent spatial patterns in serial offenders, mainly for serious crimes notably serial killing and rape, but also (although with less clear patterns) for burglary. The universality of such spatial patterns are of theoretical interest in contributing to our understanding of criminal spatial behaviour and have practical significance for the possibility of using geographic profiling in developing countries. As such, burglars in India provide a particularly interesting test of the generality of the observed spatial consistencies. Information was therefore obtained on the offence location choices of 30 burglars, committing 150 offences in the Rourkela and Keonjhar districts of India. The home to crime distances were compared with those from developed countries, revealing similar but slightly shorter distances. In addition, the domocentricity of criminal spatial activity, reflected in the ,marauder' model (Canter & Gregory 1994) was tested through examination of the Canter Circle hypothesis, the mean interpoint distances (as they related to average distances from home), and the home base ,search costs' using a geographical profiling system (Dragnet). Overall the study found that the spatial patterns of the sample of Indian Burglars were not very different from their counterparts in the UK, North America and Australia, showing that the areas in which an offender is active tend to be shaped by, and, relatedly, close to, where he or she lives, irrespective of the part of the world in which this is. These results suggest that geographical profiling systems such as Dragnet would be productively used on the Indian sub-continent. The results also contribute to our understanding of possible universalities in offender spatial behaviour. Copyright © 2006 John Wiley & Sons, Ltd. [source] Self-Regulation and the Problem of Human Autonomy: Does Psychology Need Choice, Self-Determination, and Will?JOURNAL OF PERSONALITY, Issue 6 2006Richard M. Ryan ABSTRACT The term autonomy literally refers to regulation by the self. Its opposite, heteronomy, refers to controlled regulation, or regulation that occurs without self-endorsement. At a time when philosophers and economists are increasingly detailing the nature of autonomy and recognizing its social and practical significance, many psychologists are questioning the reality and import of autonomy and closely related phenomena such as will, choice, and freedom. Using the framework of self-determination theory (Ryan & Deci, 2000), we review research concerning the benefits of autonomous versus controlled regulation for goal performance, persistence, affective experience, quality of relationships, and well-being across domains and cultures. We also address some of the controversies and terminological issues surrounding the construct of autonomy, including critiques of autonomy by biological reductionists, cultural relativists, and behaviorists. We conclude that there is a universal and cross-developmental value to autonomous regulation when the construct is understood in an exacting way. [source] PREFERENCE FOR ONE OF TWO IDENTICAL STIMULI: EXPECTATIONS, EXPLICIT INSTRUCTIONS AND PERSONAL TRAITSJOURNAL OF SENSORY STUDIES, Issue 2010KATHRYN W. CHAPMAN ABSTRACT Most consumers, given two identical food samples, express a preference for one, rather than choosing a no-preference option. The stability and potential causes of this seemingly irrational preference were examined across three trials under different conditions, specifically, when the first test pair was identical or different, and when participants were explicitly told that the pairs would often be identical. Choice of no preference typically increased from the first to second trial, especially for groups who saw a pair of different samples on the first trial. The explicit instruction that samples might be the same failed to reduce expressing a preference on the initial trial although it had some effect on later trials. Analysis, by individuals, of sequences of preference or no-preference responses across trials support independence of sequential responses and argue against stable personal traits as a predictor of preference choice. PRACTICAL APPLICATIONS More research needs to be done to understand the origins and operation of biases in preference tests. When tested under conditions in which the samples differ only slightly, participants tend to avoid the no-preference option. This is potentially important when interpreting the results of preference tests and assigning practical significance to their outcomes. Also, single trial testing may produce somewhat different results from multi-trial testing, the latter allowing for examination of effects of variation in recent experience. [source] Changes in inhibitory activity and secondary conformation of soybean trypsin inhibitors induced by tea polyphenol complexationJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 14 2009Huihua Huang Abstract BACKGROUND: Tea polyphenol (TP) is a new food additive for antioxidant application, while soybean is an important resource for food and feed processing. It is therefore of rational and practical significance to investigate the influence of TP on soybean trypsin inhibitors (TIs). The aim of this study was to determine the effects of TP on the inhibitory activity of Kunitz (KTI) and Bowman,Birk (BBTI) TIs and to reveal the relationship between the inhibitory activity and conformation of KTI and BBTI by measurement of circular dichroism (CD) spectra. RESULTS: KTI and BBTI were found to be partially deactivated by TP. BBTI exhibited stronger resistance than KTI to TP deactivation. The unchanged KM value of trypsin for benzoyl- DL -arginine- p -nitroanilide hydrolysis indicated that KTI and BBTI inhibited trypsin in a non-competitive pattern when complexed with TP. As the TP/TI ratio was increased and the inhibitory activity of KTI and BBTI decreased, the conformation of KTI and BBTI showed relevant changes and the major CD negative bands shifted progressively towards the near-UV region. CONCLUSION: These results show the deactivation effects of TP on KTI and BBTI and reveal preliminarily the relationship between the inhibitory activity and secondary structure of KTI and BBTI. Copyright © 2009 Society of Chemical Industry [source] Contrasting longitudinal and cross-sectional relationships between insulin resistance and percentage of body fat, fitness, and physical activity in children,the LOOK studyPEDIATRIC DIABETES, Issue 8 2009Richard D Telford Background: Knowledge of individual changes in insulin resistance (IR) and longitudinal relationships of IR with lifestyle-associated factors are of important practical significance, but little longitudinal data exist in asymptomatic children. We aimed to determine (a) changes in the homeostatic model of insulin resistance (HOMA-IR) over a 2-yr period and (b) comparisons of longitudinal and cross-sectional relationships between HOMA-IR and lifestyle-related risk factors. Methods: Our subjects, 241 boys and 257 girls, were assessed at age 8.1 yr (SD 0.35) and again 2 yr later for fasting blood glucose and insulin, dual X-ray absorptiometry-assessed percentage of body fat (%BF), pedometer-assessed physical activity (PA), and cardio-respiratory fitness (CRF) by multistage running test. Results: HOMA-IR was initially 9% greater in girls than boys and 27% greater 2 yr later. There was no evidence of longitudinal relationships between HOMA-IR and %BF in boys or girls, despite significant cross-sectional relationships (p < 0.001). In boys, there was evidence of a longitudinal relationship between HOMA-IR and both PA (p < 0.001) and CRF (p = 0.05). In girls, we found a cross-sectional relationship between HOMA-IR and CRF (p < 0.001). Conclusions: HOMA-IR increases between 8 and 10 yr of age and to a greater extent in girls. Longitudinal, unlike cross-sectional, relationships do not support the premise that body fat has any impact on HOMA-IR during this period or that PA or CRF changes affect HOMA-IR in girls. These data draw attention to difficulties in interpreting observational studies in young children. [source] Differences between Ventricular Repolarization in Men and Women: Description, Mechanism and ImplicationsANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 4 2003Borys Surawicz M.D., M.A.C.C. The purpose of this review article is to discuss the differences between ventricular repolarization in males and females in terms of morphology, possible mechanism, and practical significance. The interest in the subject increased when it became known that in comparison to men, women have a higher incidence of torsade de pointes (tdp) and a greater lengthening of QT-interval after administration of class III antiarrhythmic drugs. Before puberty, the QT intervals and the patterns of ventricular repolarization in boys and girls are similar. At puberty, in boys the QT interval shortens, and a typical male pattern of ventricular repolarization develops. This pattern is characterized by a higher amplitude of the J-point, a shorter and steeper ST segment course, a steeper ascent, and a higher amplitude of the T wave. This pattern is prevalent in >90% of young males. With increasing age the prevalence of the male pattern in males declines gradually and drops to 14% in the oldest age group. The rise and fall of the prevalence of the male pattern appears to parallel the rise and decline of testosterone in males. The female pattern of ventricular repolarization is prevalent in about 80% of females in all age groups. The hormonal effects on ventricular repolarization have been studied in normal and castrated rabbits of both sexes. The available evidence indicates that the females have greater divergence of L calcium current among different layers of the myocardium and a lower density of the repolarizing Kr and Ks currents. The clinical significance of the repolarization differences among genders remains to be determined. Of particular interest is the question whether the males with female pattern are at the same risk of tdp as the females or whether the females with male pattern are at lower risk of tdp than the females with female pattern. [source] Interviewer feedback in repeated interviews involving forced confabulationAPPLIED COGNITIVE PSYCHOLOGY, Issue 4 2007Jessica M. Hanba The effects of confirmatory interviewer feedback on eyewitness testimony following forcibly confabulated and accurate responses to repeated interview questions were investigated in two experiments. The first experiment showed that, relative to neutral feedback, confirmatory feedback provided after a forcibly confabulated response greatly increased the likelihood that participants would provide the same confabulated response when re-interviewed 2 days later, led participants to report these repeated confabulations with greater speed and fewer expressions of doubt, and increased the prevalence of false memories. Confirmatory interviewer feedback provided following accurate responses appeared to have more modest consequences for consistency and confidence, but ceiling effects provided little opportunity for observing potential effects. A second experiment showed that these effects of confirmatory feedback are of considerable practical significance, in that, regardless of their accuracy, responses that had earlier been reinforced with confirmatory feedback were much more likely to be judged by others as credible. Copyright © 2006 John Wiley & Sons, Ltd. [source] Application in stochastic volatility models of nonlinear regression with stochastic designAPPLIED STOCHASTIC MODELS IN BUSINESS AND INDUSTRY, Issue 2 2010Ping Chen Abstract In regression model with stochastic design, the observations have been primarily treated as a simple random sample from a bivariate distribution. It is of enormous practical significance to generalize the situation to stochastic processes. In this paper, estimation and hypothesis testing problems in stochastic volatility model are considered, when the volatility depends on a nonlinear function of the state variable of other stochastic process, but the correlation coefficient |,|,±1. The methods are applied to estimate the volatility of stock returns from Shanghai stock exchange. Copyright © 2009 John Wiley & Sons, Ltd. [source] | ||||||||||||||||||||||||||||