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Regular
Terms modified by Regular Selected AbstractsREGULAR(IZED) HEDGE FUND CLONESTHE JOURNAL OF FINANCIAL RESEARCH, Issue 3 2010Daniel Giamouridis Abstract This article addresses the problem of portfolio construction in the context of efficient hedge fund investments replication. We propose a modification to the standard Sharpe "style analysis" by introducing a constraint on the asset weights 1-norm and 2-norm. This constraint regularizes the optimization problem, allows efficient selection of relevant factor's and has significant effects on the stability of the resulting asset mix and the risk,return characteristics of the replicating portfolio. The empirical results suggest that the norm-constrained replicating portfolios exhibit significant correlations with their benchmarks, often higher than 0.9; have a fraction, which is about half to two-thirds, of active positions relative to those determined through the standard method; and are obtained with turnover, which is in some instances about one-fourth of that for the standard method. [source] Failure to reduce drinking and driving in France: a 6-year prospective study in the GAZEL cohortADDICTION, Issue 1 2010Aymery Constant ABSTRACT Aim An unprecedented decline in alcohol consumption and road mortality has been observed recently in France, but it is still unclear whether or not these changes affected driving while alcohol-intoxicated (DWI). The objective of the study was to estimate prospectively trends of excessive speed on the roads, alcohol consumption and DWI between 2001 and 2007 in a large cohort of experienced drivers. Methods Participants were current employees or recent retirees of the French national electricity and gas company, who volunteered to participate in a research cohort established in 1989 under strict conditions of anonymity. An annual cohort questionnaire is sent to participants that includes two questions about overall alcohol consumption. In 2001 and 2007, 10 684 participants reported their driving behaviours using the same self-administered questionnaire. Results Between 2001 and 2007, the proportion of participants (n = 10 684) who reported having driven at speeds at least 20 km/hour above the limit decreased from 23.7% to 4.1% in built-up areas (P < 0.001), from 34.3% to 9.3% on rural roads (P < 0.001) and from 24.3% to 2.7% on highways (P < 0.001). Regular and non-regular excessive alcohol consumption decreased from 22.7% to 19.7% and from 18.0% to 14.9%, respectively, whereas DWI increased from 22.9% to 25.3% over the same period (P < 0.001). Conclusions A recent crackdown on road violations by the French government has failed to deter DWI. Given that DWI seems to be a sporadic and rarely punished behaviour, its prevention requires more coercive measures, such as using a breath alcohol ignition interlock device. [source] Changing pattern of care of boys with haemophilia in western European centresHAEMOPHILIA, Issue 2 2005H. Chambost Summary., Haemophilia management is not uniform among countries, even within western Europe, that have close economic, social and cultural relationship. The European Paediatric Network PedNet aims to share experiences in the field of the care of boys with haemophilia. In 1998, a PedNet survey has shown significant disparities in 20 centres from 16 countries, particularly as regards the implementation of prophylaxis regimen. This survey has been updated in 2003 to describe the current status of haemophilia management in 22 centres and the changing pattern of care of boys with severe haemophilia in western Europe. Regular, continuous long-term prophylaxis is provided in all PedNet centres, more than 50% and 80,100% of boys being treated this way in 20/22 and 15/22 centres respectively. Twenty of the 22 centres (91%) recommend continuous prophylaxis (primary or secondary A) for a new patient. The use of recombinant factor VIII concentrates was already widespread in 1998 and a further expansion of recombinant products has been observed over the last 5 years. Recombinant FVIII is now used exclusively in nine centres and for more than 80% of boys with haemophilia A in nine other centres. The use of recombinant and plasma derived FIX is more balanced: among 18 centres where boys with haemophilia B are treated, 14 use recombinant FIX, and nine administer it to a majority of patients. Other modifications of practice have been stressed in this survey, such as more targeted use of central venous devices in the youngest boys and more extensive characterisation of genetic mutations. [source] Nursing Time Devoted to Medication Administration in Long-Term Care: Clinical, Safety, and Resource ImplicationsJOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 2 2009Mary S. Thomson PhD OBJECTIVES: To quantify the time required for nurses to complete the medication administration process in long-term care (LTC). DESIGN: Time-motion methods were used to time all steps in the medication administration process. SETTING: LTC units that differed according to case mix (physical support, behavioral care, dementia care, and continuing care) in a single facility in Ontario, Canada. PARTICIPANTS: Regular and temporary nurses who agreed to be observed. MEASUREMENTS: Seven predefined steps, interruptions, and total time required for the medication administration process were timed using a personal digital assistant. RESULTS: One hundred forty-one medication rounds were observed. Total time estimates were standardized to 20 beds to facilitate comparisons. For a single medication administration process, the average total time was 62.0±4.9 minutes per 20 residents on physical support units, 84.0±4.5 minutes per 20 residents on behavioral care units, and 70.0±4.9 minutes per 20 residents on dementia care units. Regular nurses took an average of 68.0±4.9 minutes per 20 residents to complete the medication administration process, and temporary nurses took an average of 90.0±5.4 minutes per 20 residents. On continuing care units, which are organized differently because of the greater severity of residents' needs, the medication administration process took 9.6±3.2 minutes per resident. Interruptions occurred in 79% of observations and accounted for 11.5% of the medication administration process. CONCLUSION: Time requirements for the medication administration process are substantial in LTC and are compounded when nurses are unfamiliar with residents. Interruptions are a major problem, potentially affecting the efficiency, quality, and safety of this process. [source] Regular or "Super-Aspirins"?JOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 4 2001A Review of Thienopyridines or Aspirin to Prevent Stroke PURPOSE: To review the evidence for the effectiveness and safety of the thienopyridines (ticlopidine and clopidogrel) compared with aspirin for the prevention of vascular events among patients at high risk of vascular disease. BACKGROUND: Atherosclerosis and resultant cardiovascular disease are important causes of morbidity and mortality in older people. In particular, atherosclerosis of the cerebral arteries can lead to transient ischemic attacks (TIAs) and stroke. Stroke ranks as the third-leading cause of death in the United States and in 1997 was responsible for over 150,000 fatalities.1 In addition to the mortality associated with this disease, stroke is also a leading source of long-term disability in survivors. Nearly 4.5 million stroke survivors are alive today,1 highlighting the fact that primary, but also secondary, prevention are extremely important for minimizing the complications of this illness. DATA SOURCES: Specialized trial registers of the Cochrane Stroke Group and the Antithrombotic Trialist's Collaboration, MEDLINE, and Embase were searched. Additional unpublished information and data were sought from Sanofi, the pharmaceutical company that developed and manufactures ticlopidine and clopidogrel, as well as the principal investigators of the Clopidogrel versus Aspirin in Patients at Risk of Ischemic Events (CAPRIE) trial,7 the largest of the trials identified. STUDY SELECTION CRITERIA: All unconfounded randomized trials comparing either ticlopidine or clopidogrel with aspirin among patients at high risk of vascular disease (those with symptoms of ischemia of the cerebral, coronary, or peripheral circulations) who were followed for at least 1 month for the recurrence of vascular events were included. DATA EXTRACTION: Data were extracted from four completed randomized trials completed in the past 20 years, which included 22,656 patients.7,10 Two authors independently extracted the data from these trials for the following information: the types of patients enrolled; the entry and exclusion criteria; the randomization method; the number of patients originally allocated to the treatment and control groups; the method and duration of follow-up; the number of patients in each group lost to follow-up; information on compliance with the treatment allocated; the definitions of outcome events; the number of outcome events in each treatment group; and any method used for blinding patients, treating clinicians, and outcome assessors to treatment allocation. MAIN RESULTS: Four completed trials involving a total of 22,656 patients were identified. Aspirin was compared with ticlopidine in three trials (3,471 patients)8,10 and with clopidogrel in one trial (19,185 patients).7 A recent TIA or ischemic stroke was the qualifying event in 9,840 patients, a recent myocardial infarction in 6,302 patients, and symptomatic peripheral arterial disease in 6,514 patients. The average age of the patients was approximately 63, with approximately two-thirds of the patients being male and white. The duration of follow-up ranged from 12 to 40 months. CONCLUSIONS: This systematic review demonstrates that, compared with aspirin, thienopyridines are only modestly more effective in preventing serious vascular events in high-risk patients. For patients who are intolerant of, or allergic to aspirin, the available safety and efficacy data suggest that clopidogrel is an appropriate, but more-expensive, alternative antiplatelet drug. It appears safer than ticlopidine and as safe as aspirin but it should not replace aspirin as the first-choice antiplatelet agent for all patients. Further studies are necessary to determine which, if any, particular types of patients would benefit most and least from clopidogrel instead of aspirin. [source] Adherence to a daily flossing regimen in university students: effects of planning when, where, how and what to do in the face of barriersJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 9 2006Benjamin Schüz Abstract: Objectives: Regular (daily) dental flossing is recommended for preventing oral diseases, but adherence is unsatisfactory. Social cognitive theory (SCT) specifies determinants of dental flossing: Cognitions about risk, positive and negative outcome expectations and the perceived ability to perform behaviour predict motivation, which in turn predicts behaviour. Recent research suggests that motivation alone may not suffice to predict behaviour, and proposes if-then-planning. This study aims to predict flossing adherence from social cognitive variables and planning. Material and Methods: Questionnaire data from 157 non-dental university students on flossing, SCT variables and planning were gathered at three measurement points over 6 weeks. Residual floss was used to validate behaviour self-reports. Results: Social cognitive variables and planning correlated significantly with flossing at all times. Discriminant function analysis suggests that after controlling for Time 1 flossing, planning Time 2 (Wilk's ,=0.77; p<0.01) is more important in discriminating between adherent and non-adherent participants at Time 3 than Time 1 social cognitive measures. Regression analyses confirmed this result with planning as only predictor of flossing change (p<0.05). Conclusions: These results suggest targeting planning in interventions to increase compliance with flossing recommendations. Implications for such interventions are discussed. [source] The Effect of Denture Cleansing Solutions on the Retention of Yellow Hader Clips: An In Vitro StudyJOURNAL OF PROSTHODONTICS, Issue 3 2007Reena M. Varghese DMD Purpose: To evaluate the retention of yellow Hader clips after exposure to various denture cleansers. Methods: Seven groups of 18 yellow Hader clips each were soaked for the equivalent of 6 months of clinical use in the following denture cleansing solutions: Polident Regular, Polident Overnight, Efferdent, 5.25% Sodium Hypochlorite (NaOCl, 1:10 dilution) 15 min/day, NaOCl (1:10 dilution) 8 hours/day, water and dry (control) group. A Universal Testing Machine, set at a crosshead speed of 2 in/min, pulled each clip once, and the peak load-to-dislodgement was recorded and used as a measure to reflect changes in the retention of the Hader clips. Data were analyzed by a one-way analysis of variance followed by Tukey's HSD test. A p value , 0.05 was considered significant. Results: Denture cleansing solutions affected the retentive values of yellow Hader clips (F= 6.102, p, .0001). Sodium hypochlorite solution, 15 min/day for 6 months, caused an increase in the retentive values of the clips tested with a mean peak load-to-dislodgement of 22.63 ± 1.29 N. In addition, clips soaked in water showed no difference in retentive values when compared with all other groups. Furthermore, Polident Regular, Polident Overnight, Efferdent, and NaOCl (8 hours/day) had no effect on the retentive values of yellow Hader clips. Conclusion: This in vitro study demonstrated that the retention of yellow Hader clips used in implant overdentures is unaffected when soaked in commercial effervescent denture cleansers (Polident 5 Minute, Polident Overnight, and Efferdent) for six simulated months. Sodium hypochlorite statistically increased the single-pull retentive values of the clips, an effect that may not be beneficial. Increased retentive values may be associated with reduced durability of clips; further research is needed to address this issue. [source] School Disrepair and Substance Use Among Regular and Alternative High School StudentsJOURNAL OF SCHOOL HEALTH, Issue 8 2010Rachel A. Grana MPH BACKGROUND: The physical environment influences adolescent health behavior and personal development. This article examines the relationship between level of school disrepair and substance use among students attending regular high school (RHS) and alternative high school (AHS). METHODS: Data were collected from students (N = 7058) participating in 2 randomized controlled trials of a school-based substance abuse prevention program implemented across the United States. Students provided substance use and demographic information on a self-reported survey. Data for the physical disrepair of schools were collected from individual rater observations of each school environment. We hypothesized that school disrepair would be positively associated with substance use controlling for individual characteristics and a socioeconomic status proxy. Multilevel mixed modeling was used to test the hypothesized association and accounted for students nested within schools. RESULTS: Findings indicated that students attending AHS with greater school disrepair were more likely to report the use of marijuana and other illicit drugs (ie, cocaine, heroin). Students attending RHS with greater school disrepair were less likely to report smoking cigarettes. CONCLUSIONS: Differences in findings between RHS and AHS students are discussed, and implications for substance use prevention programming are offered. Students attending AHS with greater school disrepair may require more substance abuse prevention programming, particularly to prevent illicit substance use. [source] Review article: the clinical importance of growth in children with inflammatory bowel disease: is it important to the gastroenterologist?ALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 2007J. A. TAMINIAU Summary Background, Growth in children with inflammatory bowel disease is often compromised. Aim, To explore the origins of growth retardation in paediatric inflammatory bowel disease and to consider management strategies. Methods, Relevant literature was identified and reviewed. Results, A combination of the following factors results in growth retardation: insufficient food intake, malabsorption, increased catabolism, disease activity, disease extension, complications of disease and the side-effects of treatment. Conclusions, Failure of normal growth in a child with inflammatory bowel disease is an indicator of insufficient and unsuccessful therapy. The major causative factor is chronic anorexia because of chronic catabolic illness. Growth resumes to normal after effective control of the disease and nutritional intake. Regular follow-up of growth in these children is mandatory, and the measurement of both height and weight is an ideal indication of effective treatment. Failure of sustained growth in a child or adolescent with inflammatory bowel disease is a warning to consider a change of clinical strategy. [source] The natural history of parallel transjugular intrahepatic portosystemic stent shunts using uncovered stent: the role of host-related factorsLIVER INTERNATIONAL, Issue 5 2006Ahmed Helmy Abstract: Objectives: Parallel shunts (PS) are used in the management of transjugular intrahepatic portosystemic stent-shunt (TIPS) insufficiency, a major limitation of the technique. This study describes the natural history of PS, and uses them as a model to assess the role of host factors in the development of primary shunt insufficiency. Methods: Out of 338 patients with TIPS, 40 (11.8%) patients required insertion of a PS. Baseline and follow-up data of these patients were collected. Regular shunt surveillance involved biannual clinic visits and transjugular portography. Results: The non-PS group (group 1; n=298) and the PS group (group 2; n=40) had similar baseline demographic and disease characteristics. Index shunts of both groups and the PS produced a significant portal pressure gradient drop (P<0.001), which was less in the index shunts of Group 2 (P<0.02 for both). PS had similar cumulative shunt patency rates to those of the index shunts of Group 1, and both were greater than those of index shunts in Group 2 (P<0.001 for both). The intervention rate (number of interventions/number of check portograms × 100) was similar for PS and the index shunts of Group 1 (38.7% and 43% respectively), but was significantly higher in the index shunts of Group 2 (85.6%; P<0.01 for both). In Group 1 and Group 2, 144 patients (48.3%) and 21 patients (52.5%) died during follow-up after a median period of 23.4 and 8.9 months respectively. Conclusions: These findings do not support the hypothesis that shunt insufficiency is related to host factors. [source] Colorectal cancer prevention in ulcerative colitis: a case-control studyALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 2 2000Eaden Background: The risk of colorectal cancer (CRC) in ulcerative colitis (UC) increases with extent and duration of disease. Identifying other risk factors would allow targeting of sub-groups at greatest risk, enabling more cost-effective surveillance. Methods: We conducted a case-control study comparing 102 cases of CRC in UC with matched controls. Odds ratios (OR) for cancer risk were estimated by conditional logistic regression. A multivariate model assessed the contribution of individual variables. Results: Regular 5-aminosalicylic acid (5-ASA) therapy reduces cancer risk by 75% (OR 0.25, 95% CI: 0.13,0.48, P < 0.00001). Adjusting for other variables, taking mesalazine regularly reduces risk by 81% (OR 0.19, 95% CI: 0.06,0.61, P=0.006) and visiting a hospital doctor more than twice a year also reduces risk (OR 0.16, 95% CI: 0.04,0.60, P=0.007). Considering variables independently, having a family history of sporadic CRC in any relative increases risk fivefold (OR 5.0, 95% CI: 1.10,22.82, P < 0.04). Conclusions: CRC risk among UC patients can be reduced by regular therapy with 5-ASA medication. Colonoscopic surveillance may be best targeted on those unable to take 5-ASAs (e.g. due to allergy) and those with a positive family history of CRC. [source] x-f choice: Reconstruction of undersampled dynamic MRI by data-driven alias rejection applied to contrast-enhanced angiographyMAGNETIC RESONANCE IN MEDICINE, Issue 4 2006Shaihan J. Malik Abstract A technique for reconstructing dynamic undersampled MRI data, termed "x-f choice," was developed and applied to dynamic contrast-enhanced MR angiography (DCE-MRA). Regular undersampling in k-t space (a hybrid of k -space and time) creates aliasing in the conjugate x-f space that must be resolved. When regions in the object containing fast dynamic change are sparse, as in DCE-MRA, signal overlap caused by aliasing is often much less than the undersample factor would imply. x-f Choice reconstruction identifies overlapping signals using a model of the full non-aliased x-f space that is automatically generated from the undersampled data, and applies parallel imaging (PI) to separate them. No extra reference scans are required to generate either the model or the coil sensitivity maps. At each location in the reconstructed images, g -factor noise amplification is compared with predicted reconstruction errors to obtain an optimized solution. Acceleration factors greater than the number of receiver coils are possible, but are limited by the sparseness of the dynamic content and the signal-to-noise ratio (SNR) (in DCE-MRA the latter is dominant). Temporal fidelity was validated for up to a factor 10 speed-up using retrospectively undersampled data from a six-coil array. The method was tested on volunteers using fivefold prospective undersampling. Magn Reson Med, 2006. © 2006 Wiley-Liss, Inc. [source] Impact of an exercise and walking protocol on quality of life for elderly people with OA of the kneePHYSIOTHERAPY RESEARCH INTERNATIONAL, Issue 3 2003Rosângela Corrêa Dias Abstract Background and Purpose The knee is the weight-bearing joint most commonly affected by osteoarthritis (OA). The symptoms of pain, morning stiffness of short duration and physical dysfunction in the activities of daily living (ADL) can have an effect on many aspects of health, affecting quality of life. Regular and moderate physical activity adapted to individuals' life-styles and education, and joint protection strategies have been advocated as conservative management. The purpose of the present study was to assess the impact of an exercise and walking protocol on the quality of life of elderly people with knee OA. Method The study design was a randomized controlled clinical trial. The subjects comprised 50 elderly people, aged 65 or more, with knee OA who had been referred to the geriatric outpatient unit for rehabilitation. Changes in severity of pain and quality of life were compared between a control group (CG) and an experimental group (EG). Both groups participated in an educational session and the EG also received a 12-week exercise and walking protocol. Both groups were assessed at baseline and after three and six months by an independent observer. The Lequesne Index of Knee OA Severity (LI), the Health Assessment Questionnaire (HAQ) and the Medical Outcomes Short-Form Health Survey (SF-36) were used as measurement instruments. Results In the CG, the measures of quality of life (SF-36), the HAQ and the LI between subjects did not yield statistically significant differences over the three measurement points. For the EG, there was a significant improvement in function, measured by HAQ, and decreasing OA symptom severity, measured by LI. For the SF-36 there were significant improvements in physical function, functional role limitation and pain. Comparisons between the groups showed statistically significant differences after three and six months for all measures, except for the SF-36 emotional domains. Conclusion The exercise protocol and walking programme had a positive effect on the quality of life of elderly individuals with knee OA. Copyright © 2003 Whurr Publishers Ltd. [source] Regular and inverted batch process structures for pressure swing distillation: a case studyASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 6 2009Andreas Klein Abstract The main focus of this paper is on the comparison of the inverted and the regular pressure swing batch distillation processes for the separation of a homogenous azeotropic mixture. On the basis of a successful, experimentally validated rigorous model, a simulation study to identify the differences between the two processes and the influences of different structures on them is carried out. This identification of influences helps in finding out a heuristic base of the most suitable batch structure for a given separation problem. Especially the influence of the feed flow rate on the processes and the differences between the results on operation with different pressures will be addressed. Furthermore advantages, disadvantages and the limitations of both processes will be shown. In the end the best way of operating the pressure swing batch distillation will be presented depending on the product purity and the feed concentration for a given example. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Station level gasoline demand in an Australian market with regular price cycles,AUSTRALIAN JOURNAL OF AGRICULTURAL & RESOURCE ECONOMICS, Issue 4 2009Zhongmin Wang Regular and frequent gasoline price cycles are being observed in many Australian and Canadian markets. What is driving these price cycles has been the subject of academic studies and government investigations. The existing explanations for these price cycles all rely on the presumption that drivers are intensively sensitive to gasoline price differentials at the station level. However, no empirical evidence exists in the literature to support this presumption. This paper provides the first piece of empirical evidence. This paper uses a unique price and quantity data set and novel instruments to estimate the station level gasoline demand in the cycling market of Perth, Australia. The elasticity estimates confirm that drivers in the Perth area are indeed very sensitive to gasoline price differentials. [source] Conformational analysis of endomorphin-1 by molecular dynamics methodsCHEMICAL BIOLOGY & DRUG DESIGN, Issue 4 2003B. Leitgeb Abstract: Endomorphin-1 (EM1, H-Tyr-Pro-Trp-Phe-NH2) is a highly potent and selective agonist for the ,-opioid receptor. A conformational analysis of this tetrapeptide was carried out by simulated annealing and molecular dynamics methods. EM1 was modeled in the neutral (NH2 -) and cationic (NH -) forms of the N-terminal amino group. The results of NMR measurements were utilized to perform simulations with restrained cis and trans Tyr1 -Pro2 peptide bonds. Preferred conformational regions in the ,2,,2, ,3,,3 and ,4,,4 Ramachandran plots were identified. The g(+), g(,) and trans rotamer populations of the side-chains of the Tyr1, Trp3 and Phe4 residues were determined in ,1 space. The distances between the N-terminal N atom and the other backbone N and O atoms, and the distances between the centers of the aromatic side-chain rings and the Pro2 ring were measured. The preferred secondary structures were determined as different types of , -turns and , -turns. In the conformers of trans -EM1, an inverse , -turn can be formed in the N-terminal region, but in the conformers of cis -EM1 the N-terminal inverse , -turn is absent. Regular and inverse , -turns were observed in the C-terminal region in both isomers. These , - and , -turns were stabilized by intramolecular H-bonds and bifurcated H-bonds. [source] A Fast Simulation Method Using Overlapping Grids for Interactions between Smoke and Rigid ObjectsCOMPUTER GRAPHICS FORUM, Issue 2 2008Yoshinori Dobashi Abstract Recently, many techniques using computational fluid dynamics have been proposed for the simulation of natural phenomena such as smoke and fire. Traditionally, a single grid is used for computing the motion of fluids. When an object interacts with a fluid, the resolution of the grid must be sufficiently high because the shape of the object is represented by a shape sampled at the grid points. This increases the number of grid points that are required, and hence the computational cost is increased. To address this problem, we propose a method using multiple grids that overlap with each other. In addition to a large single grid (a global grid) that covers the whole of the simulation space, separate grids (local grids) are generated that surround each object. The resolution of a local grid is higher than that of the global grid. The local grids move according to the motion of the objects. Therefore, the process of resampling the shape of the object is unnecessary when the object moves. To accelerate the computation, appropriate resolutions are adaptively-determined for the local grids according to their distance from the viewpoint. Furthermore, since we use regular (orthogonal) lattices for the grids, the method is suitable for GPU implementation. This realizes the real-time simulation of interactions between objects and smoke. [source] Effect of slice angle on inhomogeneity artifact and its correction in slice-selective MR imagingCONCEPTS IN MAGNETIC RESONANCE, Issue 4 2009Kwan-Jin Jung Abstract The inhomogeneity of a local magnetic field causes an image artifact of geometric distortion and intensity abnormality because of the slice offset and readout shift in slice-selective MR imaging. It has been found that this artifact can be corrected by the projection of the slice offset onto the readout axis at a certain oblique slice angle. The slice angle for the artifact correction is determined by the amplitude of slice selection and readout gradients, and is independent of the magnetic field inhomogeneity and the main magnetic field direction. In addition, the existing view-angle tilting technique is found to be valid only for the slice orientation orthogonal to the object axis. The slice angle effect on the inhomogeneity artifact was confirmed experimentally through phantom and volunteer's head imaging for both regular and view-angle tilted spin echo sequences at 3 T. © 2009 Wiley Periodicals, Inc.Concepts Magn Reson Part A 34A: 238,248, 2009. [source] Longstanding malformation of right sided pinna in an elderly manCONGENITAL ANOMALIES, Issue 1 2010Deeke Yolmo ABSTRACT The pinna is the second most common site for external ear vascular malformation in the head and neck. These malformations are relatively uncommon in adults and can pose difficult therapeutic challenges. We hereby present a case of a 69-year-old man with a congenital lesion in the right pinna consistent with an arteriovenous malformation. The lesion was complicated by ulceration and bleeding for 6 months prior to presentation. Resection of pinna was carried out, and satisfactory functional and esthetic results were obtained. There was no recurrence at 22 months of regular follow up. [source] Grazing Intensity and the Diversity of Grasshoppers, Butterflies, and Trap-Nesting Bees and WaspsCONSERVATION BIOLOGY, Issue 6 2002Andreas Kruess The reduction of management intensity can be a useful tool for the long-term conservation of the biological diversity of grasslands. We analyzed floral and faunal diversity on intensively and extensively (unintensively) grazed pastures and on 5- to 10-year-old ungrazed grasslands in northern Germany. Each of the three grassland habitats differing in grazing intensity was replicated six times. We related diverse taxa such as grasshoppers, butterfly adults and lepidopteran larvae, and trap-nesting solitary bees and wasps to vegetation structure. There was an increase of species richness and abundance from pastures to ungrazed grasslands. The percentage of parasitism of the most abundant trap-nesting species, the digger-wasp ( Trypoxylon figulus), was also higher on ungrazed grasslands. Decreased grazing on pastures enhanced species richness for adult butterflies only, whereas the abundance of adult butterflies, solitary bees and wasps, and their natural enemies increased. Although the differences in insect diversity between pastures and ungrazed grassland could be attributed to a greater vegetation height and heterogeneity ( bottom-up effects) on ungrazed areas, the differences between intensively and extensively grazed pastures could not be explained by changes in vegetation characteristics. Hence, intensive grazing appeared to affect the insect communities through the disruption of plant-insect interactions. A mosaic of extensively grazed grassland and grassland left ungrazed for a few years may be a good means by which to maintain biodiversity and the strength of trophic interactions. Resumen: El mantenimiento de pastizales como hábitats distintos depende del manejo regular, generalmente, por medio de pastoreo o segado, pero se sabe que la diversidad de especies declina con el incremento de intensidad de manejo. La reducción de la intensidad de manejo puede ser una herramienta útil para la conservación a largo plazo de la biodiversidad de pastizales. Analizamos la diversidad florística y faunística en pastizales pastoreados intensiva y extensivamente (no intensivos) y en pastizales de 5 a 10 años no pastoreados en el norte de Alemania. Cada uno de los tres hábitats de pastizal diferentes en el grado de pastoreo fue replicado seis veces. Relacionamos diversos taxones como chapulines, mariposas adultas, larvas de lepidópteros y abejas y avispas solitarias con la estructura de la vegetación. Hubo un incremento en la riqueza y abundancia de especies de pastizales pastoreados a no pastoreados. El porcentaje de parasitismo de la especie de avispa más abundante ( Trypoxylon figulus) también fue mayor en pastizales no pastoreados. La reducción del pastoreo incrementó la riqueza de especies de mariposas adultas solamente, mientras que incrementó la abundancia de mariposas adultas, abejas y avispas solitarias y sus enemigos naturales. Aunque las diferencias en la diversidad de insectos entre pastizales pastoreados y no pastoreados pudiera atribuirse a la mayor altura de la vegetación y a la heterogeneidad (efectos abajo-arriba) en áreas no pastoreadas, las diferencias entre pastizales pastoreados intensiva y extensivamente no podría explicarse por cambios en las características de la vegetación. Por consiguiente, el pastoreo intensivo aparentemente afectó a las comunidades de insectos por la disrupción de las interacciones planta-animal. Un mosaico de pastizales pastoreados extensivamente y pastizales sin pastoreo por varios años puede ser una buena estrategia para mantener la biodiversidad y la vigencia de las interacciones tróficas. [source] Calmodulin kinase II initiates arrhythmogenicity during metabolic acidification in murine heartsACTA PHYSIOLOGICA, Issue 1 2009T. H. Pedersen Abstract Aim:, The multifunctional signal molecule calmodulin kinase II (CaMKII) has been associated with cardiac arrhythmogenesis under conditions where its activity is chronically elevated. Recent studies report that its activity is also acutely elevated during acidosis. We test a hypothesis implicating CaMKII in the arrhythmogenesis accompanying metabolic acidification. Methods:, We obtained monophasic action potential recordings from Langendorff-perfused whole heart preparations and single cell action potentials (AP) using whole-cell patch-clamped ventricular myocytes. Spontaneous sarcoplasmic reticular (SR) Ca2+release events during metabolic acidification were investigated using confocal microscope imaging of Fluo-4-loaded ventricular myocytes. Results:, In Langendorff-perfused murine hearts, introduction of lactic acid into the Krebs-Henseleit perfusate resulted in abnormal electrical activity and ventricular tachycardia. The CaMKII inhibitor, KN-93 (2 ,m), reversibly suppressed this spontaneous arrhythmogenesis during intrinsic rhythm and regular 8 Hz pacing. However, it failed to suppress arrhythmia evoked by programmed electrical stimulation. These findings paralleled a CaMKII-independent reduction in the transmural repolarization gradients during acidosis, which previously has been associated with the re-entrant substrate under other conditions. Similar acidification produced spontaneous AP firing and membrane potential oscillations in patch-clamped isolated ventricular myocytes when pipette solutions permitted cytosolic Ca2+ to increase following acidification. However, these were abolished by both KN-93 and use of pipette solutions that held cytosolic Ca2+ constant during acidosis. Acidosis also induced spontaneous Ca2+ waves in isolated intact Fluo-4-loaded myocytes studied using confocal microscopy that were abolished by KN-93. Conclusion:, These findings together implicate CaMKII-dependent SR Ca2+ waves in spontaneous arrhythmic events during metabolic acidification. [source] Lithium and KB-R7943 effects on mechanics and energetics of rat heart muscleACTA PHYSIOLOGICA, Issue 1 2002P. Bonazzola ABSTRACT The role of calcium influx on energy expenditure during cardiac contraction was studied. For this purpose, the described ability of lithium and KB-R 7943 (KBR) to diminish Ca entry through Na,Ca exchanger (Ponce-Hornos & Langer, J Mol Cell Cardiol 1980, 12, 1367, Satoh et al., Circulation 2000, 101, 1441) were used. In isolated contractions (contractions elicited after at least 5 min of rest) LiCl 45 mmol L,1 decreased pressure developed and pressure,time integral from 42.3 ± 2.7 and 14.5 ± 1.2 to 32.1 ± 3.4 mN mm,2 and 8.3 ± 0.9 mN mm,2 s, respectively. A similar effect was observed in regular contractions (at 0.16 Hz stimulation). The presence of KBR (5 ,mol L,1) in the perfusate induced a slight but not significant decrease in pressure developed and pressure,time integral in steady-state contractions. As it was previously described, the heat involved in a heart muscle contraction can be decomposed into several components (H1, H2, H3 and H4), but only one (H3) was associated with force generation. While H3 decreased with lithium in both types of contractions, H3/PtI ratio remained unaltered, indicating that the economy for pressure maintenance was unaffected. To further investigate the role of Ca entry on force development, a condition in which the contraction is mainly dependent on extracellular calcium was studied. An ,extra' stimulus applied 200 ms after the regular one in a muscle stimulated at 0.16 Hz induces a contraction with this characteristic (Marengo et al., Am J Physiol 1999, 276, H309). Lithium induced a strong decrease in pressure,time integral and H3 associated with this contraction (43 and 45%, respectively) with no change in H3/PtI ratio. Lithium also reduced (53%) an energy component (H2) associated with Ca cycling. The use of KBR showed qualitatively similar results [i.e. a 33% reduction in pressure,time integral associated with the extrasystole (ES) with no changes in H3/PtI ratio and a 30% reduction in the H2 component]. Li and KBR effects appear to be additive and in the presence of 45 mmol L,1 Li and 5 ,mol L,1 KBR the extrasystole was abolished in 77%. Lithium and KBR effects particularly for the extrasystole can be explained through the inhibition of Ca entry via Na,Ca exchange giving support to the participation of the Na,Ca exchanger in the Ca influx from the extracellular space. In addition, the results also suggest the possibility of an effect of Li on an additional Ca sensitive locus (different than the Na,Ca exchanger). In this connection, in isolated contractions lithium decreased the energy release fraction related to mitochondrial processes (H4) increasing the economy of the overall cardiac contraction. [source] Fate of developing tooth buds located in relation to mandibular fractures in three infancy casesDENTAL TRAUMATOLOGY, Issue 4 2010Kazuhiko Yamamoto Three infants, 2 girls and a boy, aged from 1 year and 5-months old to 2 years and 6-months old, were treated for dislocated mandibular fracture in the symphyseal region by manual reduction and fixation with a thermoforming splint and circumferential wiring under general anesthesia. Fracture healing was uneventful in all cases. A few years later, no obvious deformity of the jaw or malocclusion was observed; however, malformation of the crown was found in one of the permanent teeth on the fracture line in the first case. In the second case, no abnormality was observed in one of the permanent teeth on the fracture line, but the effect on the other tooth could not be evaluated due to abnormality of the tooth probably not related to the injury. In the third case, root formation was arrested in one of the permanent teeth on the fracture line and the tooth was lost early after eruption. The development of tooth buds on the fracture line is not predictable and therefore, should be monitored by regular follow up. [source] The role of type and token frequency in using past tense morphemes correctlyDEVELOPMENTAL SCIENCE, Issue 2 2007Elena Nicoladis Type and token frequency have been thought to be important in the acquisition of past tense morphology, particularly in differentiating regular and irregular forms. In this study we tested the role of frequency in two ways: (1) in bilingual children, who typically use and hear either language less often than monolingual children and (2) cross-linguistically: French and English have different patterns of frequency of regular/irregular verbs. Ten French-English bilingual children, 10 French monolingual and 10 English monolingual children between 4 and 6 years watched a cartoon and re-told the story. The results demonstrated that the bilingual children were less accurate than the monolingual children. Their accuracy in both French and English regular and irregular verbs corresponded to frequency in the input language. These results are consistent with the hypothesis that children learn past tense morphemes by analogy with other words in their vocabularies. We propose a developmental sequence based on conservative generalization across a growing set of verbs. [source] Motor processes in children's imagery: the case of mental rotation of handsDEVELOPMENTAL SCIENCE, Issue 5 2005Marion Funk In a mental rotation task, children 5 and 6 years of age and adults had to decide as quickly as possible if a photograph of a hand showed a left or a right limb. The visually presented hands were left and right hands in palm or in back view, presented in four different angles of rotation. Participants had to give their responses with their own hands either in a regular, palms-down posture or in an inverted, palms-up posture. For both children and adults, variation of the posture of their own hand had a significant effect. Reaction times were longer the more awkward it was to bring their own hand into the position shown in the stimulus photograph. These results, together with other converging evidence, strongly suggest that young children's kinetic imagery is guided by motor processes, even more so than adults'. [source] The histology of the Upper Silurian osteostracan Timanaspis kossovoii Obruchev (Agnatha) from North Timan, RussiaACTA ZOOLOGICA, Issue 2009Olga B. Afanassieva Abstract The fine structure of the exoskeleton of Timanaspis kossovoii Obruchev 1962 was investigated based on new well-preserved material. The remains come from the lower part of the Eptarma Formation (Upper Silurian). Timanaspis kossovoii was referred by Obruchev to the family Tremataspididae and most authors agree with the placement of Timanaspis among tremataspidid osteostracans. Histological study of the shield of T. kossovoii has revealed the presence of unusual features in the exoskeletal structure. The smooth and shiny surface of the ventral side of the shield of T. kossovoii is similar to that of species of Tremataspis, but thin sections show differences in histological composition. The exoskeleton of T. kossovoii consists mainly of dense bony tissue in the middle layer and a laminated basal layer. No osteocyte cavities of typical form and size were found in the middle layer. The upper parts of the elongated tubercles of the dorsal side of the shield are formed by a well-developed dentine-like tissue; the arrangement of numerous tubules within this tissue is far more regular than in the mesodentine of Tremataspis. No traces of perforated septa, pore fields or a polygonal model were detected in the structure of the exoskeleton of Timanaspis. We conclude that Timanaspis can be differentiated from conventional tremataspidids by histological features and refer it to the new family Timanaspididae. Moreover, the Timanaspis exoskeleton provides evidence that an acellular condition of bony tissue does not appear to be characteristic of only Late Devonian osteostracans. [source] Changes in the initiation of heroin use after a reduction in heroin supplyDRUG AND ALCOHOL REVIEW, Issue 4 2006CAROLYN DAY Abstract Increasing heroin use in Australia over the past 30 years has been associated with a decline in the age of initiation to heroin use. The 2001 Australian heroin shortage was used to assess the effects of a reduction in heroin supply on age of initiation into heroin injecting. Data collected from regular injecting drug users (IDU) over the period 1996,2004 as part of the Australian Illicit Drug Reporting System were examined for changes in self-reported age of first heroin use after the onset of the heroin shortage. Estimates were also made of the number of young people who may not have commenced injecting heroin during the heroin shortage. The proportion of IDU interviewed in the IDRS who were aged ,24 years decreased from 46% in 1996 to 12% in 2004, with the most marked drop in 2001, the year in which there was an abrupt and marked reduction in heroin availability. Of those who reported first injecting between 1993 and 2000, similar proportions reported heroin and amphetamine as the first drug injected. After 2000, methamphetamine was the drug most often reported as being the first injected. Estimates suggested that between 2745 and 10 560 young people may not have begun to inject heroin in 2001 as a result of reduced heroin supply. If around one in four of these young users had progressed to regular or dependent heroin use, then there may have been a reduction of between 700 and 2500 dependent heroin users. There was an increase in amphetamine injecting but it is unclear to what extent any reduction in heroin injecting has been offset by increased amphetamine injecting. Reduced heroin availability probably resulted in a reduction in the number of new heroin injectors in Australia. Efforts need to be made to reduce the chances that young people who have initiated methamphetamine injecting do not move to heroin injecting when the heroin supply returns. [source] Expected impacts of the Cannabis Infringement Notice scheme in Western Australia on regular users and their involvement in the cannabis marketDRUG AND ALCOHOL REVIEW, Issue 4 2005FRANCOISE CHANTELOUP Abstract The effect on the cannabis market is one area of interest in the evaluation of the new ,prohibition with civil penalties' scheme for minor cannabis offences in WA. One goal of the scheme is to reduce the proportion of cannabis consumed that is supplied by large-scale suppliers that may also supply other drugs. As part of the pre-change phase of the evaluation, 100 regular (at least weekly) cannabis users were given a qualitative and quantitative interview covering knowledge and attitudes towards cannabis law, personal cannabis use, market factors, experience with the justice system and impact of legislative change. Some 85% of those who commented identified the changes as having little impact on their cannabis use. Some 89% of the 70 who intended to cultivate cannabis once the CIN scheme was introduced suggested they would grow cannabis within the two non-hydroponic plant-limit eligible for an infringement notice under the new law. Only 15% believed an increase in self-supply would undermine the large scale suppliers of cannabis in the market and allow some cannabis users to distance themselves from its unsavoury aspects. Only 11% said they would enter, or re-enter, the cannabis market as sellers as a result of the scheme introduction. Most respondents who commented believed that the impact of the legislative changes on the cannabis market would be negligible. The extent to which this happens will be addressed in the post-change phase of this research. Part of the challenge in assessing the impact of the CIN scheme on the cannabis market is that it is distinctly heterogeneous. [source] Monitoring and predicting channel change in a free-evolving, small Alpine river: Ridanna Creek (North East Italy)EARTH SURFACE PROCESSES AND LANDFORMS, Issue 14 2007Rossella Luchi Abstract The recent (25 years) morphodynamics of a proglacial reach of the Ridanna Creek, North-East Italy, evolving in the absence of human constraints, has been investigated by means of an intensive field activity and of the analysis of aerial photographs. The study reach mostly displays a braided morphology, with sharp downstream variations of valley gradient, sediment size and formative conditions within the main channel. These discontinuities are associated with different processes of channel adjustment at different timescales, which have been quantified by coupling hydrological with morphological information. Several processes of channel change and variations in braiding intensity have been documented along the whole reach and highlight how a regular, weakly meandering main channel may significantly affect the morphodynamics of the braided network. A first attempt to predict the morphological instability of this main channel at the observed spatial scales through existing linear theories of curved river channels shows a good agreement with field observations. Finally, the complete hydro-morphodynamical characterization of such an undisturbed alpine river reach can provide a relevant contribution to the definition of reference conditions for Alpine rivers required by the EU Water Framework Directive. Copyright © 2007 John Wiley & Sons, Ltd. [source] Optimal design of supplemental viscous dampers for irregular shear-frames in the presence of yieldingEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 8 2005Oren Lavan Abstract A methodology for the optimal design of supplemental viscous dampers for regular as well as irregular yielding shear-frames is presented. It addresses the problem of minimizing the added damping subject to a constraint on an energy-based global damage index (GDI) for an ensemble of realistic ground motion records. The applicability of the methodology for irregular structures is achieved by choosing an appropriate GDI. For a particular choice of the parameters comprising the GDI, a design for the elastic behavior of the frame or equal damage for all stories is achieved. The use of a gradient-based optimization algorithm for the solution of the optimization problem is enabled by first deriving an expression for the gradient of the constraint. The optimization process is started for one ,active' ground motion record which is efficiently selected from the given ensemble. If the resulting optimal design fails to satisfy the constraints for other records from the original ensemble, additional ground motions (loading conditions) are added one by one to the ,active' set until the optimum is reached. Two examples for the optimal designs of supplemental dampers are given: a 2-story shear frame with varying strength distribution and a 10-story shear frame. The 2-story shear frame is designed for one given ground motion whereas the 10-story frame is designed for an ensemble of twenty ground motions. Copyright © 2005 John Wiley & Sons, Ltd. [source] | |||||||||||||||||||||||||||||||||||||||||||