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Greater Variability (greater + variability)
Selected AbstractsPersonality and absenteeism: a meta-analysis of integrity testsEUROPEAN JOURNAL OF PERSONALITY, Issue S1 2003Deniz S. Ones Until recently, research focus has been on a variety of demographic, attitudinal, and organizational variables in predicting and explaining absenteeism. If personality traits predict absenteeism, then it may be possible to use measures of these traits to identify and select job applicants and thereby reduce absenteeism rates. In this research, our goal was to examine whether integrity tests could be used to predict absenteeism. Meta-analysis was applied to studies of the validity of pre-employment integrity tests for predicting voluntary absenteeism. Twenty-eight studies based on a total sample of 13,972 were meta-analysed. The estimated mean predictive validity of personality-based integrity tests was 0.33. This operational validity generalized across various predictor scales, organizations, settings, and jobs (SD,,=,0.00). Overt integrity tests, however, showed much lower predictive validity for absenteeism and greater variability than personality-based tests (,,=,0.09; SD,,=,0.16). The results indicate that a personnel selection approach to reducing absenteeism in organizations may be a useful strategy, particularly if personality-based integrity tests are utilized. Potential explanations for differences between these results and those found for Big Five measures of personality are offered. Future research investigating models of absenteeism should incorporate the personality constructs assessed by integrity tests. Copyright © 2003 John Wiley & Sons, Ltd. [source] Stability of cognitive impairment in chronic schizophrenia over brief and intermediate re-test intervalsHUMAN PSYCHOPHARMACOLOGY: CLINICAL AND EXPERIMENTAL, Issue 2 2009Robert H. Pietrzak Abstract Objective This study examined between- and within-subject stability of cognitive performance in individuals with chronic schizophrenia. Methods Thirty individuals with schizophrenia and 20 healthy controls matched by age, sex, education, and estimated IQ underwent repeated cognitive assessments at baseline and 30 days using computerized tests of psychomotor function, visual attention/information processing, non-verbal learning, and executive function. Results Compared to healthy controls, individuals with schizophrenia scored lower on all cognitive measures and demonstrated greater variability in cognitive performance. Within-subject variability in cognitive performance in both the schizophrenia and healthy control groups remained stable at brief (i.e., hours) and intermediate (i.e., one month) assessments. Conclusions These results demonstrate the stability of between- and within-subject variability in cognitive performance in schizophrenia, and suggest that variability in cognitive performance may reflect an inherent characteristic of the disorder, rather than differences in test,retest reliability/error of cognitive measures. Copyright © 2008 John Wiley & Sons, Ltd. [source] Predicting river width, depth and velocity at ungauged sites in England and Wales using multilevel modelsHYDROLOGICAL PROCESSES, Issue 20 2008D. J. Booker Abstract Using a dataset of gauged river discharges taken from sites in England and Wales, linear multilevel models (also known as mixed effects models) were applied to quantify the variability in discharge and the discharge-hydraulic geometry relationships across three nested spatial scales. A jackknifing procedure was used to test the ability of the multilevel models to predict hydraulic geometry, and therefore width, mean depth and mean velocity, at ungauged stations. These models provide a framework for making predictions of hydraulic geometry parameters, with associated levels of uncertainty, using different levels of data availability. Results indicate that as one travels downstream along a river there is greater variability in hydraulic geometry than is the case between rivers of similar sizes. This indicates that hydraulic geometry (and therefore hydrology) is driven by catchment area, to a greater extent than by natural geomorphological variations in the streamwise direction at the mesoscale, but these geomorphological variations can still have a major impact on channel structure. Copyright © 2008 John Wiley & Sons, Ltd. [source] Subtle deficits of attention after surgery: quantifying indicators of sub syndrome deliriumINTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY, Issue 10 2010David Peter Lowery Abstract Objective To determine whether attentional impairments are reliable neuropsychological markers of sub syndrome delirium. Method A prospective cohort study with repeated assessment beginning pre-operatively and continuing through the first post-operative week. Computerized assessments of attention and the Mini-Mental State Examination were administered with one hundred patients admitted for elective orthopedic surgery, 70 years and over and free of dementia. Acute change of cognitive status was used to identify cases of sub syndrome delirium. Results There were significant differences of post-surgical performance between the ,no delirium' and ,sub-syndrome delirium' groups of reaction time, global cognition, accuracy and greater variability of reaction time (p,<,0.041). There were significant within subject main effects on reaction time (p,=,0.001), variability of reaction time (p,=,0.022) and MMSE (p,=,0.000) across the cohort; but no significant interaction effect of ,diagnosis' * ,time' on the computerized measures of attention (p,>,0.195). Conclusion The distinction between people with sub syndrome delirium and no delirium is difficult to quantify but computerized measures of attention might provide a sensitive indicator. Sub syndrome delirium is an observable marker of a clinical abnormality that should be exploited to improve care management for vulnerable patients. Copyright © 2010 John Wiley & Sons, Ltd. [source] Hypothalamic,Pituitary,Adrenocortical Axis Dysregulation in Acute Temporomandibular Disorder and Low Back Pain: A Marker for Chronicity?,JOURNAL OF APPLIED BIOBEHAVIORAL RESEARCH, Issue 3-4 2006John P. Garofalo Dysregulation of the hypothalamic,pituitary,adrenocortical (HPA) axis is believed to be a valid biological marker of stress. This study evaluating changes in patients with temporomandibular disorders (TMD) and low back pain (LBP) to determine whether dysregulation of this system represents a marker for chronicity. Salivary cortisol samples were collected from 78 patients (TMD = 41, LBP = 37) upon waking up and 20 minutes later daily for 2 weeks. High-risk patients for chronic pain had different overall cortisol levels versus low-risk patients. High-risk patients exhibited greater variability in terms of cortisol secretion compared with low-risk patients, F(1, 1,243) = 17.73, p < .000. These results provide evidence of a neuroendocrine mechanism underlying a constellation of psychosocial risk factors for chronic pain. [source] Early stages of protein crystallization as revealed by emerging optical waveguide technologyJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 3 2008Attia Boudjemline A highly sensitive method for studying the onset of protein crystallization in real time using an optical-waveguide-based technique is reported. Dual polarization interferometry uses light from sensing and reference waveguides to produce an interference pattern, which when the sensing waveguide is immersed in a protein solution supplies information on the thickness and density of any protein adlayer on the sensing waveguide's surface. This technique provides evidence that crystallization proceeds via large protein aggregates but, more strikingly, shows dramatic light loss from the sensing waveguide at a very early stage during crystallization. The technique proves relatively insensitive to the crystallization of small molecules or poorly formed protein crystals and affords a method of distinguishing crystal formation from the formation of other protein aggregates or salt crystals. The experimental setup currently necessitates crystallization using the batch method, and precipitant mixing at high supersaturation is known to introduce a greater variability compared with methods such as vapour diffusion or dialysis, but first results promise to bridge the paucity of real-time methods available to distinguish the onset of protein crystallization from other forms of aggregation. [source] Amplified fragment length polymorphism (AFLP) and biochemical typing of Photobacterium damselae subsp. damselaeJOURNAL OF APPLIED MICROBIOLOGY, Issue 4 2002S. Botella Aims: The aim of the present study was to characterize subspecifically Photobacterium damselae subsp. damselae strains isolated from cultured Sparus aurata and Dicentrarchus labrax by means of phenotypic and molecular typing techniques (amplified fragment length polymorphism, AFLP). Methods and Results: Seventy-one strains of P. damselae subsp. damselae were isolated from 38 cultured fishes at different fish farms located on the Mediterranean coast near Valencia, Spain. Most fish studied were asymptomatic and some were recovered during infectious outbreaks. Phenotypic characterization revealed a considerable degree of variability within the subspecies, including some characters, such as production of urease, which are used to differentiate P. damselae subsp. damselae from P. damselae subsp. piscicida. Genetic characterization was conducted on a selection of 33 strains, including two reference strains. Dice coefficient (Sd) and the unweighted pair group method with average linkage (UPGMA) were used for numerical analysis of banding patterns. AFLP type was defined on the basis of 100% similarity in the dendrogram obtained, yielding 24 distinct AFLP profiles. At 70% similarity, 13 clusters were defined, thus confirming the great variability observed for the phenotypic traits. Conclusions: The AFLP variability shown by the isolates was high enough to discriminate between different strains which colonize the same fish. However, closely related AFLP types were usually derived from strains isolated at the same fish farm, indicating an epidemiological relationship. Significance and Impact of the Study: This study has confirmed that the AFLP technique allows discrimination of individual strains within P. damselae subsp. damselae for epidemiological studies, and that this subspecies exhibits greater variability than that described for subspecies piscicida. [source] Evolution, origin and age of lineages in the Californian and Mediterranean florasJOURNAL OF BIOGEOGRAPHY, Issue 7 2009David D. Ackerly Abstract This paper addresses some of the conceptual issues involved in the analysis of the age and origin of mediterranean-climate plant taxa, paying particular attention to three topics: (1) the importance of an explicit time frame in the definition of biogeographical origins, (2) the distinction between the age of traits and the age of taxa, and (3) the idea of mediterranean-type ecosystems as environmental islands. (1) In California, recent analyses demonstrate that the diversity of species derived from different biogeographical origins is significantly correlated with temperature and precipitation gradients. These patterns support the hypothesis that niche conservatism is an important factor structuring modern diversity gradients. However, depending on how far back in time one looks, a species may be assigned to different origins; future discussions of biogeographical origins need to address the appropriate time frame for analysis. (2) Past research has demonstrated distinctive trait syndromes among woody plants of the Mediterranean, Chile, California and Mexico, and proposed that the syndromes are associated with lineages of different age in these floras. Reanalysis of individual traits demonstrates greater variability among regions than previously reported. The classification of plants into ,old' and ,new' genera is re-evaluated, and it is suggested that greater attention be paid to the age of traits, rather than to the age of taxa, especially at an arbitrary rank such as genus. (3) The idea of mediterranean-climate regions as ,climatic islands' is examined. Space,time diagrams of climate enable one to view the emergence of distinctive climatic regions in a continental context. The terms ,synclimatic' and ,anticlimatic' are proposed, referring to migration routes that parallel climate contours in space and time versus those that cross contours (including the case of geographic stasis in the face of climate change), respectively. Mediterranean-climate regions have served as important case studies in plant ecology and evolution, and merit continued close examination in the light of continued advances in phylogenetics and palaeoecology. [source] A Sex Difference by Item Difficulty Interaction in Multiple-Choice Mathematics Items Administered to National Probability SamplesJOURNAL OF EDUCATIONAL MEASUREMENT, Issue 1 2001John Bielinski A 1998 study by Bielinski and Davison reported a sex difference by item difficulty interaction in which easy items tended to be easier for females than males, and hard items tended to be harder for females than males. To extend their research to nationally representative samples of students, this study used math achievement data from the 1992 NAEP, the TIMSS, and the NELS:88. The data included students in grades 4, 8, 10, and 12. The interaction was assessed by correlating the item difficulty difference (bmale, bfemale) with item difficulty computed on the combined male/female sample. Using only the multiple-choice mathematics items, the predicted negative correlation was found for all eight populations and was significant in five. An argument is made that this phenomenon may help explain the greater variability in math achievement among males as compared to females and the emergence of higher performance of males in late adolescence. [source] The relationship between flesh quality and numbers of Kudoa thyrsites plasmodia and spores in farmed Atlantic salmon, Salmo salar L.JOURNAL OF FISH DISEASES, Issue 8 2003J A Dawson-Coates Abstract Atlantic salmon, Salmo salar L., were exposed to Kudoa thyrsites (Myxozoa, Myxosporea)-containing sea water for 15 months, and then harvested and assessed for parasite burden and fillet quality. At harvest, parasites were enumerated in muscle samples from a variety of somatic and opercular sites, and mean counts were determined for each fish. After 6 days storage at 4 °C, fillet quality was determined by visual assessment and by analysis of muscle firmness using a texture analyzer. Fillet quality could best be predicted by determining mean parasite numbers and spore counts in all eight tissue samples (somatic and opercular) or in four fillet samples, as the counts from opercular samples alone showed greater variability and thus decreased reliability. The variability in both plasmodia and spore numbers between tissue samples taken from an individual fish indicated that the parasites were not uniformly distributed in the somatic musculature. Therefore, to best predict the probable level of fillet degradation caused by K. thyrsites infections, multiple samples must be taken from each fish. If this is performed, a mean plasmodia count of 0.3 mm,2 or a mean spore count of 4.0 × 105 g,1 of tissue are the levels where the probability of severe myoliquefaction becomes a significant risk. [source] Caregiver Acceptability and Preferences for Early Childhood Caries Preventive Treatments for Hispanic ChildrenJOURNAL OF PUBLIC HEALTH DENTISTRY, Issue 4 2009Sally H. Adams RN Abstract Objective: The objective of this study was to determine caregiver treatment acceptability and preferences for five preventive dental treatments for early childhood caries in young Hispanic children. Methods: We interviewed 211 parents/caregivers of Hispanic children attending Head Start programs regarding their acceptability of, and preferences for, five standard preventive dental treatments for young children. Treatments assessed were toothbrushing with fluoride toothpaste, fluoride varnish, and xylitol in food for children, and xylitol gum and chlorhexidine rinse for mothers. The interview assessment included presentation of illustrated cards with verbal description of treatment, photograph/video clip, and treatment samples. Parents rated the acceptability of each treatment (1-5 scale) and treatment preferences within each of 10 possible pairs. Individual treatment preferences were summed to create overall preference scores (range 0-4). Results: All treatments were rated as highly acceptable, however, there were differences (range 4.6-4.9; Friedman chi-square = 23.4, P < 0.001). Chlorhexidine, toothbrushing, and varnish were most acceptable, not different from each other, but more acceptable than xylitol in food (P < 0.05). Summed treatment preferences revealed greater variability (means ranged 1.4-2.6; Friedman chi-square = 128.2, P < 0.001). Fluoride varnish (2.6) and toothbrushing (2.5) were most highly preferred, and differences between preferences for xylitol in food (1.4), xylitol gum (1.5), and chlorhexidine (2.1) were all significant (P < 0.001). Preferences for chlorhexidine were also significantly greater than those for the xylitol products (P < 0.001). Conclusions: All five treatments were highly acceptable, however, when choosing among treatments overall, fluoride varnish and toothbrushing were favored over other treatments. [source] Teachers' expectations about students' use of reading strategies, knowledge and behaviour in Grades 3, 5 and 7JOURNAL OF RESEARCH IN READING, Issue 2 2001Fatemeh Arabsolghar Although extensive basic research has been carried out on children's metacognition, little is known about teachers' views of their students' cognitive and metacognitive skills in reading. The ways in which teachers expected their children to use, or to know how to use, certain reading skills are examined in this study. A questionnaire on reading components (strategies, knowledge and behaviour) was completed by 45 teachers in Grades 3, 5 and 7. In this questionnaire teachers were asked to make judgements about whether or not students of high, average and low ability levels in their classes would be likely to show these skills. An analysis of variance (grade×ability×component) revealed a significant interaction between ability and component. There was much greater variability in the three components for the low and average levels of ability. The main effect for ability was significant. The highest expectations of teachers were for high-ability students in all the three groups of items, followed by average and low-ability students. The main effect for component was also significant for knowledge. There was no significant difference between the grades. However, teachers hold equivalent performance expectations for high-ability students in each of the three components, but for average and low-ability groups, expectations were higher for knowledge than strategy and behaviour. [source] Development of an Index of Biotic Integrity for a Southeastern Coastal Plain Watershed, USA,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 2 2007Charles C. Morris Abstract:, This study evaluated biological integrity expectations of fish assemblages in wadeable streams for the Alabama portion of the Choctawhatchee River watershed using a multimetric approach. Thirty-four randomly selected stream sites were sampled in late spring 2001 to calibrate an index of biotic integrity (IBI). Validation data were collected during the spring 2001, and summer and fall of 2003 from disturbed and least-impacted targeted sites (n = 20). Thirty-five candidate metrics were evaluated for their responsiveness to environmental degradation. Twelve metrics were selected to evaluate wadeable streams and four replacement metrics were selected for headwater streams. Scores that ranged from 58 to 60 were considered to be representative of excellent biotic integrity (none found in this study), scores of 48-52 as good integrity (31% of the sites in this study), 40-44 as fair (43%), 28-34 as poor (21%), and 12-22 as very poor (5%). Of the four stream condition categories (urban, cattle, row crop, and least impacted), the IBI scores for urban and cattle sites differed significantly from least-impacted sites. Row crop sites, although not significantly different from least-impacted, tended to have greater variability than the other categories. Lower IBI scores at both urban and cattle sites suggest that the IBI accurately reflects stream impairment in the Choctawhatchee River drainage. [source] Different methods of creatinine measurement significantly affect MELD scoresLIVER TRANSPLANTATION, Issue 4 2007Evangelos Cholongitas Bilirubin (Bil) interferes with creatinine (Cr) measurement. Different laboratory methods are used to overcome this problem. Model for end-stage liver disease (MELD) scoring incorporates Cr and is used to prioritize patients for liver transplantation. Thus, MELD scores may vary with different Cr measurements influencing patients' priority. Our aim was to evaluate 4 different Cr assays (O'Leary modified Jaffe [mJCr], compensated [rate blanked] kinetic Jaffe [cJCr], enzymatic [ECr], and standard kinetic Jaffe [JCr]) in patients with abnormal liver function tests and assess changes in MELD score. A total of 403 consecutive samples from 158 patients' Cr assays were evaluated.. Bland-Altman plots and MELD scores were also evaluated for each assay. Agreement was found to be poor among all Cr assays. Increased variability in Cr occurred with increasing Bil concentrations: Bil <100 ,mol/L ,3-point MELD variation - 3-point difference in 2%; Bil ,400,mol/L ,7-point MELD variation - ,3-point difference in 78%. When MELD was ,25 (mJCr as reference; mean, 30.5 points), MELD variation was greatest: mean, 28 (MELD cJCr), 27.5 (MELD ECr), and 28.4 (MELD JCr) (P < 0.001). In conclusion, there is poor agreement among different assays for Cr. As Bil concentration rises, there is greater variability in each creatinine measurements and thus greater variability in MELD scores that, this affect prioritization for liver transplantation. Liver Transpl, 2006. © 2006 AASLD. [source] Within population variation and interrelationships between morphology, nutritional content, and secondary compounds of Rhamnus alaternus fruitsNEW PHYTOLOGIST, Issue 2 2002Ido Izhaki Summary ,,We studied within-species variation in and interrelations among morphological and chemical traits of ripe Mediterranean buckthorn ( Rhamnus alaternus ) fruit, a bird-dispersed species. ,,Principal component analysis revealed that larger fruits tended to be relatively rich in nonstructural carbohydrates (NSC), water and P but poor in protein and most minerals. Small fruits tended to be relatively rich in protein, structural carbohydrates, K and Zn while intermediate size fruits tended to be rich in lipids, Mg and Ca. Variation in chemical traits (organic compounds and minerals) was typically much higher than in morphological traits (e.g. fruit size) with the exception of NSC and water content, which varied little. This discrepancy might be explained by differences in environmental conditions between plant microsites that imposed greater variability on fruit nutrient composition than on fruit-morphological traits; and by lower selective pressure by birds on fruit chemical traits than on morphological traits. ,,Secondary metabolite (emodin) concentration was positively correlated with concentrations of NSC, supporting the nutrient/toxin titration model, which predicts that high levels of secondary metabolites in fruits should be off set by high nutritional rewards for dispersers. ,,Emodin concentration in leaves was much higher than in fruit pulp, which may indicate its differential adaptive roles in seed dispersal and against herbivores. [source] Standardized T2* map of normal human heart in vivo to correct T2* segmental artefactsNMR IN BIOMEDICINE, Issue 6 2007Vincenzo Positano Abstract A segmental, multislice, multi-echo T2* MRI approach could be useful in heart iron-overloaded patients to account for heterogeneous iron distribution, demonstrated by histological studies. However, segmental T2* assessment in heart can be affected by the presence of geometrical and susceptibility artefacts, which can act on different segments in different ways. The aim of this study was to assess T2* value distribution in the left ventricle and to develop a correction procedure to compensate for artefactual variations in segmental analysis. MRI was performed in four groups of 22 subjects each: healthy subjects (I), controls (II) (thalassemia intermedia patients without iron overload), thalassemia major patients with mild (III) and heavy (IV) iron overload. Three short-axis views (basal, median, and apical) of the left ventricle were obtained and analyzed using custom-written, previously validated software. The myocardium was automatically segmented into a 16-segment standardized heart model, and the mean T2* value for each segment was calculated. Punctual distribution of T2* over the myocardium was assessed, and T2* inhomogeneity maps for the three slices were obtained. In group I, no significant variation in the mean T2* among slices was found. T2* showed a characteristic circumferential variation in all three slices. The effect of susceptibility differences induced by cardiac veins was evident, together with low-scale variations induced by geometrical artefacts. Using the mean segmental deviations as correction factors, an artefact correction map was developed and used to normalize segmental data. The correction procedure was validated on group II. Group IV showed no significant presence of segmental artefacts, confirming the hypothesis that susceptibility artefacts are additive in nature and become negligible for high levels of iron overload. Group III showed a greater variability with respect to normal subjects. The correction map failed to compensate for these variations if both additive and percentage-based corrections were applied. This may reinforce the hypothesis that true inhomogeneity in iron deposition exists. Copyright © 2007 John Wiley & Sons, Ltd. [source] Disturbance and reef topography maintain high local diversity in Ecklonia radiata kelp forestsOIKOS, Issue 10 2007Benjamin D. Toohey Disturbance of competitive-dominant plant and algae canopies often lead to increased diversity of the assemblage. Kelp forests, particularly those of temperate Western Australia, are habitats with high alpha diversity. This study investigated the roles of broad-scale canopy loss and local scale reef topography on structuring the kelp-dominated macroalgal forests in Western Australia. Eighteen 314,m2 circular areas were cleared of their Ecklonia radiata canopy and eighteen controls were established across three locations. The patterns of macroalgal recolonisation in replicate clearances were observed over a 34,month period. Macroalgal species richness initially increased after canopy removal with a turf of filamentous and foliose macroalgae dominating cleared areas for up to seven months. A dense Sargassum canopy dominated cleared areas from 11 to 22,months. By 34,months, partial recovery of the kelp canopy into cleared areas had occurred. Some cleared areas did not follow this trajectory but remained dominated by turfing, foliose and filamentous algae. As kelp canopies developed, the initial high species diversity declined but still remained elevated relative to undisturbed controls, even after 34 months. More complex reef topography was associated with greater variability in the algal assemblage between replicate quadrats suggesting colonising algae had a greater choice of microhabitats available to them on topographically complex reefs. Shading by canopies of either Sargassum spp. and E. radiata are proposed to highly influence the abundance of algae through competitive exclusion that is relaxed by disturbance of the canopy. Disturbance of the canopy in E. radiata kelp forests created a mosaic of different patch types (turf, Sargassum -dominated, kelp-dominated). These patch types were both transient and stable over the 34 months of this study, and are a potential contemporary process that maintains high species diversity in temperate kelp-dominated reefs. [source] Stimulus size and the variability of the threshold response in the central and peripheral visual fieldOPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 6 2002L. S. Kim Purpose:, The investigation of the peripheral visual field has shown considerable interest for the investigation of field loss attributed to anticonvulsant therapy. The purpose was to determine the within-visit between-subject, the between-visit between-subject, and the between-location variability of the threshold response in the normal eye with increase in stimulus eccentricity out to 60° as a function of stimulus size. Methods:, Forty-eight normal subjects attended for a total of three visits (mean age = 49.5 years, SD = 18.9, range 22,84 years). At the first visit, one randomly assigned eye of each subject was examined with the Humphrey Field Analyzer 750 (Carl Zeiss, Jena, Germany) and the Full Threshold algorithm using Programs 30,2 and 60,4 and stimulus sizes III and V. The combination of stimulus size and of program, and the order of the combination within- and between-sessions, were randomized for each subject. The results of the first visit were considered as a familiarization period and were discarded. The protocol at the second and third visits was identical to that at the first visit for each subject. Results:, The ratio of the SD of the group mean sensitivity was determined at each stimulus location for stimulus size III compared with stimulus size V for Programs 30,2 and 60,4 at visit 3. The SDs were greater than unity for Program 30,2 (p < 0.0001) and for Program 60,4 (p < 0.0001) indicating greater variability for the size III stimulus. The SDs were also greater than unity for the central inner zone (p < 0.0001), central outer zone (p < 0.0001) and peripheral inner zone (p < 0.0001). The ratios in the peripheral outer zone were not quite greater than unity (p = 0.054). The ratios increased with increase in eccentricity by up to 2.7 times between 15° and 30° eccentricity and by up to 2.7 times between 30° and 60° eccentricity. The group mean ratio did not vary significantly between the two visits for Program 30,2 stimulus size III (p = 0.563), Program 60,4 stimulus size III (p = 0.935) and for Program 60,4 stimulus size V (p = 0.005). However, the group mean SD was lower at visit 3 compared with visit 2 for Program 30,2 stimulus size V (p = 0.0004). The SDs associated with the extreme peripheral locations in the superior and nasal fields were smaller for stimulus size III because the threshold was frequently attenuated by lid and facial contour. Conclusions:, Considerably narrower confidence limits for normality for the peripheral regions of Program 30,2 and for 60,4 are demonstrated with the use of Goldmann size V. [source] Lung function testing in preschool-aged children with cystic fibrosis in the clinical settingPEDIATRIC PULMONOLOGY, Issue 5 2010Catherine L. Gangell BSc(hons) Abstract In cystic fibrosis (CF) lung function testing is a means of monitoring progression of lung disease. The preschool years have often been referred to as the "silent years" due to the previous lack suitable measures of lung function testing in this age group. This review outlines the various techniques of lung function testing in preschool children with CF in the clinical setting. This includes measures requiring tidal breathing including the forced oscillation technique, the interrupter technique, plethysmography, and multiple breath washout, as well as spirometry that requires respiratory maneuvers. We describe the feasibility and variability of different lung function methods used in preschoolers and report measurements made during tidal breathing have greater feasibility, although greater variability compared to spirometry. We also report associations with lung function and markers of CF lung disease. In the preschool age group measurements made during tidal breathing may be more appropriate in the clinic setting than those that require a higher degree of cooperation and specific respiratory maneuvers.maneuvers. Pediatr Pulmonol. 2010; 45:419,433. © 2010 Wiley-Liss, Inc. [source] Locomotor variation and bending regimes of capuchin limb bonesAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 4 2009Brigitte Demes Abstract Primates are very versatile in their modes of progression, yet laboratory studies typically capture only a small segment of this variation. In vivo bone strain studies in particular have been commonly constrained to linear locomotion on flat substrates, conveying the potentially biased impression of stereotypic long bone loading patterns. We here present substrate reaction forces (SRF) and limb postures for capuchin monkeys moving on a flat substrate ("terrestrial"), on an elevated pole ("arboreal"), and performing turns. The angle between the SRF vector and longitudinal axes of the forearm or leg is taken as a proxy for the bending moment experienced by these limb segments. In both frontal and sagittal planes, SRF vectors and distal limb segments are not aligned, but form discrepant angles; that is, forces act on lever arms and exert bending moments. The positions of the SRF vectors suggest bending around oblique axes of these limb segments. Overall, the leg is exposed to greater moments than the forearm. Simulated arboreal locomotion and turns introduce variation in the discrepancy angles, thus confirming that expanding the range of locomotor behaviors studied will reveal variation in long bone loading patterns that is likely characteristic of natural locomotor repertoires. "Arboreal" locomotion, even on a linear noncompliant branch, is characterized by greater variability of force directions and discrepancy angles than "terrestrial" locomotion (significant for the forearm only), partially confirming the notion that life in trees is associated with greater variation in long bone loading. Directional changes broaden the range of external bending moments even further. Am J Phys Anthropol, 2009. © 2009 Wiley-Liss, Inc. [source] Immunocytochemical mapping and quantification of expression of a putative type 1 serotonin receptor in the crayfish nervous systemTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 3 2005Nadja Spitzer Abstract Serotonin is an important neurotransmitter that is involved in modulation of sensory, motor, and higher functions in many species. In the crayfish, which has been developed as a model for nervous system function for over a century, serotonin modulates several identified circuits. Although the cellular and circuit effects of serotonin have been extensively studied, little is known about the receptors that mediate these signals. Physiological data indicate that identified crustacean cells and circuits are modulated via several different serotonin receptors. We describe the detailed immunocytochemical localization of the crustacean type 1 serotonin receptor, 5-HT1crust, throughout the crayfish nerve cord and on abdominal superficial flexor muscles. 5-HT1crust is widely distributed in somata, including those of several identified neurons, and neuropil, suggesting both synaptic and neurohormonal roles. Individual animals show very different levels of 5-HT1crust immunoreactivity (5-HT1crustir) ranging from preparations with hundreds of labeled cells per ganglion to some containing only a handful of 5-HT1crustir cells in the entire nerve cord. The interanimal variability in 5-HT1crustir is great, but individual nerve cords show a consistent level of labeling between ganglia. Quantitative RT-PCR shows that 5-HT1crust mRNA levels between animals are also variable but do not directly correlate with 5-HT1crustir levels. Although there is no correlation of 5-HT1crust expression with gender, social status, molting or feeding, dominant animals show significantly greater variability than subordinates. Functional analysis of 5-HT1crust in combination with this immunocytochemical map will aid further understanding of this receptor's role in the actions of serotonin on identified circuits and cells. J. Comp. Neurol. 484:261,282, 2005. © 2005 Wiley-Liss, Inc. [source] Evaluating Living Kidney Donors: Relationship Types, Psychosocial Criteria, and Consent Processes at US Transplant ProgramsAMERICAN JOURNAL OF TRANSPLANTATION, Issue 10 2007J. R. Rodrigue We conducted a survey of 132 US kidney transplant programs to examine how they evaluate and select potential living kidney donors, focusing on donor-recipient relationships, psychosocial criteria, and consent processes. There is heterogeneity in donor-recipient relationships that are considered acceptable, although most programs (70%) will not consider publicly solicited donors. Most programs (75%) require a psychosocial evaluation for all potential living donors. Most programs agree that knowledge of financial reward (90%), active substance abuse (86%), and active mental health problems (76%) are absolute contraindications to donation. However, there is greater variability in how other psychosocial issues are considered in the selection process. Consent processes are highly variable across programs: donor and recipient consent for the donor evaluation is presumed in 57% and 76% of programs, respectively. The use of 13 different informed consent elements varied from 65% (alternative donation procedures) to 86% (description of evaluation, surgery and recuperative period) of programs. Forty-three percent use a ,cooling off' period. Findings demonstrate high variability in current practice regarding acceptable donor-recipient relationships, psychosocial criteria, and consent processes. Whether greater consensus should be reached on these donor evaluation practices, especially in the context of more expansive use of living donor kidney transplantation, is discussed. [source] Decadal dynamics of tree cover in an Australian tropical savannaAUSTRAL ECOLOGY, Issue 6 2009CAROLINE E. R. LEHMANN Abstract Spatio-temporal variation in tropical savanna tree cover remains poorly understood. We aimed to quantify the drivers of tree cover in tropical mesic savannas in Kakadu National Park by relating changes in tree cover over 40 years to: mean annual rainfall, fire activity, initial tree cover and prior changes in tree cover. Aerial photography, acquired in 1964, 1984 and 2004, was obtained for fifty sites in Kakadu that spanned a rainfall gradient from approximately 1200 to 1600 mm. The remotely sensed estimates of tree cover were validated via field survey. Linear mixed effects modelling and multi-model inference were used to assess the strength and form of the relationships between tree cover and predictor variables. Over the 40 years, tree cover across these savannas increased on average by 4.94 ± 0.88%, but was spatio-temporally variable. Tree cover showed a positive albeit weak trend across the rainfall gradient. The strength of this positive relationship varied over the three measurement times, and this suggests that other factors are important in controlling tree cover. Tree cover was positively related to prior tree cover, and negatively correlated with fire activity. Over 20 years tree cover was more likely to increase if (i) tree cover was initially low or (ii) had decreased in the previous 20-year interval or (iii) there had been fewer fires. Across the examined rainfall gradient, the greater variability in fire activity and inherently higher average tree cover at the wetter latitudes resulted in greater dynamism of tree cover compared with the drier latitudes. This is consistent with savanna tree cover being determined by interactions between mean annual rainfall, tree competition and frequent fire in these tropical mesic savannas. [source] Resilience of arboreal folivores to habitat damage by a severe tropical cycloneAUSTRAL ECOLOGY, Issue 4 2008ROBYN F. WILSON Abstract Severe tropical cyclones greatly modify habitat of arboreal folivores by destroying forest canopy, reducing structure and complexity and defoliating remaining trees. We hypothesized that forest modification following severe Cyclone Larry would stress arboreal folivores of the Family Pseudocheiridae and be reflected in increased home ranges and a decrease in body condition. We conducted 19 pre-cyclone and 24 post-cyclone spotlighting surveys at a site with severe cyclone damage, and 18 post-cyclone surveys at a site with minor damage. We detected a greater number of lemuroid, Hemibelideus lemuroides and green, Pseudochirops archeri, ringtail possums as these possums remained in the severely damaged canopy and forest edge. In contrast, Herbert River ringtail possums, Pseudochirulus herbertensis, were detected in smaller numbers. We radio-tracked eight P. herbertensis before the cyclone, following two of these and nine new animals after the category 4 cyclone. No significant post-cyclone alteration in home range area or span was recorded in data pooled across the two sites or in limited post-cyclone data at the severely disturbed site, but a greater variability in home range was observed after cyclone (pooled across sites: 1.72 ± 0.77 ha; 197 ± 47 m) than before the cyclone (1.35 ± 0.30 ha; 196 ± 23 m). In contrast, pooled pre- and post-cyclone home range areas and spans were larger at the severely-disturbed site (2.08 ± 0.56 ha; 231 ± 32 m) than at the site with minor damage (0.68 ± 0.11 ha; 114 ± 25 m), suggesting resources were more widely spread at the former site. Post-cyclone home ranges were also larger at the severely damaged site (severe: 3.33 ± 1.36 ha, n = 3; minor: 0.52 ± 0.07 ha, n = 4). Condition of P. herbertensis (mass/tail length) did not differ significantly pre- and post-cyclone or between less and severely disturbed sites. These results and observations of breeding after cyclone suggest that possum populations may be resilient to severe cyclone damage under the relatively wet conditions experienced post-Cyclone Larry. [source] Consequences of soil compaction for seedling establishment: Implications for natural regeneration and restorationAUSTRAL ECOLOGY, Issue 8 2005I. E. BASSETT Abstract Soil compaction can affect seedling root development by decreasing oxygen availability and increasing soil strength. However, little quantitative information is available on the compaction tolerances of non-crop native species. We investigated the effects of soil compaction on establishment and development of two New Zealand native species commonly used in restoration programmes; Cordyline australis (Agavaceae) (cabbage tree) a fleshy rooted species, and Leptospermum scoparium (Myrtaceae) (manuka) a very finely rooted species. Seedlings were grown in a range of soil compaction levels in growth cabinet experiments. Low levels of soil compaction (0.6 MPa) reduced both the number and speed of C. australis seedlings penetrating the soil surface. In contrast, L. scoparium seedlings showed improved establishment at an intermediate compaction level. Root and shoot growth of both species decreased with increasing soil strength, with L. scoparium seedlings tolerating higher soil strengths than did C. australis. Despite these results, soil strength accounted for only a small amount of variation in root length (R2 < 0.25), due to greater variability in growth at low soil strengths. Soil strengths of 0.6 MPa are likely to pose a barrier to C. australis regeneration. This is consistent with adaptation to organic and/or soft, waterlogged soils. Active intervention may be necessary to establish C. australis from seed on many sites previously in farmland. [source] Partial-body exposure of human volunteers to 2450,MHz pulsed or CW fields provokes similar thermoregulatory responses,BIOELECTROMAGNETICS, Issue 4 2001Eleanor R. Adair Abstract Many reports describe data showing that continuous wave (CW) and pulsed (PW) radiofrequency (RF) fields, at the same frequency and average power density (PD), yield similar response changes in the exposed organism. During whole-body exposure of squirrel monkeys at 2450 MHz CW and PW fields, heat production and heat loss responses were nearly identical. To explore this question in humans, we exposed two different groups of volunteers to 2450,MHz CW (two females, five males) and PW (65,,s pulse width, 104,pps; three females, three males) RF fields. We measured thermophysiological responses of heat production and heat loss (esophageal and six skin temperatures, metabolic heat production, local skin blood flow, and local sweat rate) under a standardized protocol (30,min baseline, 45,min RF or sham exposure, 10,min baseline), conducted in three ambient temperatures (Ta,=,24, 28, and 31°C). At each Ta, average PDs studied were 0, 27, and 35,mW/cm2 (Specific absorption rate (SAR),=,0, 5.94, and 7.7,W/kg). Mean data for each group showed minimal changes in core temperature and metabolic heat production for all test conditions and no reliable differences between CW and PW exposure. Local skin temperatures showed similar trends for CW and PW exposure that were PD-dependent; only the skin temperature of the upper back (facing the antenna) showed a reliably greater increase (P,=,.005) during PW exposure than during CW exposure. Local sweat rate and skin blood flow were both Ta - and PD-dependent and showed greater variability than other measures between CW and PW exposures; this variability was attributable primarily to the characteristics of the two subject groups. With one noted exception, no clear evidence for a differential response to CW and PW fields was found. Bioelectromagnetics 22:246,259, 2001. © 2001 Wiley-Liss, Inc. [source] Economic evaluation of erythropoiesis-stimulating agents for anemia related to cancerCANCER, Issue 13 2010Scott Klarenbach MD Abstract BACKGROUND: Erythropoiesis-stimulating agents (ESA) administered to cancer patients with anemia reduce the need for blood transfusions and improve quality-of-life (QOL). Concerns about toxicity have led to more restrictive recommendations for ESA use; however, the incremental costs and benefits of such a strategy are unknown. METHODS: The authors created a decision model to examine the costs and consequences of ESA use in patients with anemia and cancer from the perspective of the Canadian public healthcare system. Model inputs were informed by a recent systematic review. Extensive sensitivity analyses and scenario analysis rigorously assessed QOL benefits and more conservative ESA administration practices (initial hemoglobin [Hb] <10 g/dL, target Hb ,12 g/dL, and chemotherapy induced anemia only). RESULTS: Compared with supportive transfusions only, conventional ESA treatment was associated with an incremental cost per quality-adjusted life year (QALY) gained of $267,000 during a 15-week time frame. During a 1.3-year time horizon, ESA was associated with higher costs and worse clinical outcomes. In scenarios where multiple assumptions regarding QOL all favored ESA, the lowest incremental cost per QALY gained was $126,000. Analyses simulating the use of ESA in accordance with recently issued guidelines resulted in incremental cost per QALY gained of >$100,000 or ESA being dominated (greater costs with lower benefit) in the majority of the scenarios, although greater variability in the cost-utility ratio was present. CONCLUSIONS: Use of ESA for anemia related to cancer is associated with incremental cost-effectiveness ratios that are not economically attractive, even when used in a conservative fashion recommended by current guidelines. Cancer 2010. © 2010 American Cancer Society. [source] Short wavelength automated perimetryACTA OPHTHALMOLOGICA, Issue 6 2001John M. Wild ABSTRACT. Short Wavelength Automated Perimetry (SWAP) utilizes a blue stimulus to preferentially stimulate the blue cones and a high luminance yellow background to adapt the green and red cones and to saturate, simultaneously, the activity of the rods. This review describes the theoretical aspects of SWAP, highlights current limitations associated with the technique and discusses potential clinical applications. Compared to white-on-white (W-W) perimetry, SWAP is limited clinically by: greater variability associated with the estimation of threshold, ocular media absorption, increased examination duration and an additional learning effect. Comparative studies of SWAP and W-W perimetry have generally been undertaken on small cohorts of patients. The conclusions are frequently unconvincing due to limitations for SWAP in the delineation of abnormality and of progressive field loss. SWAP is almost certainly able to identify glaucomatous visual field loss in advance of that by W-W perimetry although the incidence of progressive field loss is similar between the two techniques. Increasing evidence suggests that functional abnormality with SWAP is preceded by structural abnormality of the optic nerve head and/or the retinal nerve fibre layer. SWAP appears to be beneficial in the detection of diabetic macular oedema and possibly in some neuro-ophthalmic disorders. [source] | ||||||||||||||||||||||||||||||||||