Major Predictor (major + predictor)

Distribution by Scientific Domains

Selected Abstracts

The relationship between local and regional diatom richness is mediated by the local and regional environment

GLOBAL ECOLOGY, Issue 3 2009
Sophia I. Passy
ABSTRACT Aim, In this continental study, species richness at local (LSR) and regional (RSR) scales was correlated and examined as a function of stream (local) and watershed (regional) environment in an effort to elucidate what factors control diatom biodiversity across scales. Location, Conterminous United States. Methods, Data on diatom richness, stream conditions and watershed properties were generated by the US Geological Survey. In the present investigation, RSR was estimated as the total diatom richness in a hydrologic study unit and, together with stream and watershed characteristics, was included in stepwise multiple regressions of LSR. The unique and shared contributions of RSR, stream and watershed environment to the explained variance in LSR were determined by variance partitioning. RSR was regressed against stream and basin features averaged per study unit. Results, LSR responded most strongly to variability in stream manganese concentration and RSR. Other predictors included stream discharge and iron concentration, soil organic matter content and fertilization, and proportions of open water, barren land and forest in the watershed. Variance partitioning revealed that RSR had the lowest independent contribution to explained variance in LSR. Multiple regressions identified average stream iron concentration as the most important predictor of RSR. Main conclusions, Local micronutrient concentration was the major predictor of LSR, followed by RSR. Since average micronutrient supply in the region was the chief determinant of RSR, it is proposed that micronutrients had both a direct effect on LSR and an indirect effect through RSR. The same argument is extended to watershed features with an impact on stream trophic status, because of their substantial contributions to the explained variance in both LSR and RSR. Considering that the major proportion of LSR variance explained by RSR originated from the covariance of RSR with stream and watershed properties, it is concluded that the LSR,RSR relationship was mediated by the local and regional environment. [source]

Effects of body mass, climate, geography, and census area on population density of terrestrial mammals

GLOBAL ECOLOGY, Issue 5 2001
Marina Silva
Abstract Aim The aim of this study was to investigate the effects of climate, geography, census area and the distribution of body mass on the mass : density relationship in terrestrial mammal populations. Location The areas covered include most major terrestrial biomes including the tropics, savannas, and temperate forests. Method Data on population density and body mass from 827 populations belonging to 330 different terrestrial mammal species were derived from a review of the literature. Results LOWESS and polynomial regression analysis indicated that the overall mass : density relationship on log-log scales was not linear and that the slope of this relationship behaves differently across the range of body mass. Body mass explained between 37 and 67% of the variability in population density depending upon the dietary category or the biome group. We also developed two multivariate models that can explain up to 65% of the variability in population density in terrestrial mammals. We also tested for a confounding effect of census area on the mass : density relationship on log-log scales in terrestrial mammals. Conclusions Our findings support previous studies suggesting that body mass is a major predictor of the variance in population density in terrestrial mammals. We suggest that the non-linearity of the mass : density relationship may result from the fact that the overall distribution of body mass is a mixture of distributions across dietary groups and biomes. In contrast to body mass, our results indicate that climatic and geographical factors have a minor effect on population density. Although census area was closely correlated with body mass, body mass was generally a better predictor of population density than was census area. [source]

Ethanol-Regulated Genes That Contribute to Ethanol Sensitivity and Rapid Tolerance in Drosophila

ALCOHOLISM, Issue 2 2010
Eric C. Kong
Background:, Increased ethanol intake, a major predictor for the development of alcohol use disorders, is facilitated by the development of tolerance to both the aversive and pleasurable effects of the drug. The molecular mechanisms underlying ethanol tolerance development are complex and are not yet well understood. Methods:, To identify genetic mechanisms that contribute to ethanol tolerance, we examined the time course of gene expression changes elicited by a single sedating dose of ethanol in Drosophila, and completed a behavioral survey of strains harboring mutations in ethanol-regulated genes. Results:, Enrichment for genes in metabolism, nucleic acid binding, olfaction, regulation of signal transduction, and stress suggests that these biological processes are coordinately affected by ethanol exposure. We also detected a coordinate up-regulation of genes in the Toll and Imd innate immunity signal transduction pathways. A multi-study comparison revealed a small set of genes showing similar regulation, including increased expression of 3 genes for serine biosynthesis. A survey of Drosophila strains harboring mutations in ethanol-regulated genes for ethanol sensitivity and tolerance phenotypes revealed roles for serine biosynthesis, olfaction, transcriptional regulation, immunity, and metabolism. Flies harboring deletions of the genes encoding the olfactory co-receptor Or83b or the sirtuin Sir2 showed marked changes in the development of ethanol tolerance. Conclusions:, Our findings implicate novel roles for these genes in regulating ethanol behavioral responses. [source]

Effect of age on the incidence of venous thromboembolism after major surgery

R. H. White
Summary.,Background:,Most guidelines for administration of thromboprophylaxis after major surgery use age as a major predictor of postoperative venous thromboembolism (VTE). We sought to quantify the effect of age on the risk of symptomatic VTE after a spectrum of surgical procedures. Methods:,Using the California Patient Discharge Data Set and specific ICD-9-CM surgical procedure codes, we retrospectively determined the incidence of VTE diagnosed within 91 days after 40 different urgent or elective surgeries performed in the hospital between 1992 and 1996. Logistic regression was used to quantify the effect of age on the incidence of postoperative VTE and to adjust for other risk factors. Results:,1 464 452 cases underwent one of 40 different procedures (mean cases per procedure = 35 718, range 4500,145 500). There was a significant interaction between age and the type of surgery performed (P<0.0001). Qualitative analysis of the effect of age on the incidence of VTE stratified by the presence or absence of malignancy revealed three general patterns: a steady increase in the incidence of VTE with age, exemplified by appendectomy or cholecystectomy; an increase in VTE up to approximately age 65 with no increase thereafter, exemplified by total hip arthroplasty; and no effect of age on the incidence of VTE, exemplified by vascular surgery. Conclusions:,The relationship between age and the risk of VTE after surgery is complex and depends on the nature of the surgery and the underlying pathologic process. Advancing age was a significant predictor for VTE following surgeries performed for conditions not inherently associated with significant comorbidity. Conversely, advancing age was not associated with a higher incidence of VTE after surgeries performed for conditions strongly associated with serious underlying comorbidity, such as a malignancy or severe peripheral vascular disease. [source]

Allergic sensitization to cat in childhood as major predictor of incident respiratory allergy in young adults

ALLERGY, Issue 11 2007
T. Schäfer
Background:, Little is known on the predictive value of sensitization to specific aeroallergens in children with respect to asthma and hay fever incidence in young adulthood. We followed the incidence of asthma and hay fever in children (mean age 11 years) over 9 years, and analyzed the predictive value of sensitization to five common aeroallergens. Methods:, Three consecutive surveys were conducted in East German school children. Specific IgE antibodies to birch and timothy grass pollen, house dust mite, cat, and cladosporium were measured. In 1207 out of the 2453 children, the 9-year incidence of asthma and hay fever was assessed by reported doctors' diagnoses. For sensitization, diagnostic parameters were determined and logistic regression analyses controlled for relevant confounders. Results:, A total of 176/78 incident hay fever/asthma cases occurred equaling a cumulative incidence of 1.93/0.86% per year. Incident asthma was associated with previous sensitization to cat [risk ratio (RR) 3.49, 1.57,7.74] and grass pollen (RR 1.79, 1.01,3.19), whereas incident hay fever was associated with each allergen, with grass pollen (RR 6.00, 4.04,8.90) and cat (RR 5.36, 2.87,9.99) exhibiting the strongest associations. When mutually adjusting for all allergens, sensitization to cat remained significantly associated with asthma and hay fever. The latter was also associated with sensitization to grass pollen. The highest positive predictive values for asthma and hay fever were obtained for cat sensitization (10/49 = 20.4% and 23/49 = 46.9%). Conclusions:, Childhood sensitization to cat and grass pollen predicts the incidence of asthma and hay fever in young adulthood. The predictive capacity differs by allergen and manifestation of atopy. [source]

Pseudomonas aeruginosa and other predictors of mortality and morbidity in young children with cystic fibrosis,

Julia Emerson MD
Abstract We conducted a registry-based study to determine prognostic indicators of 8-year mortality and morbidity in young children with cystic fibrosis (CF). Patients ages 1,5 years from the 1990 U.S. Cystic Fibrosis Foundation (CFF) National Patient Registry served as the study cohort (N,=,3,323). Registry data provided information on baseline characteristics in 1990, 8-year mortality, and clinical outcomes in 1998. P. aeruginosa respiratory infection was found to be a major predictor of morbidity and mortality. The 8-year risk of death was 2.6 times higher in patients who had respiratory cultures positive for P. aeruginosa in 1990 (95% confidence interval 1.6, 4.1) than in children without P. aeruginosa in their respiratory cultures. Culture-positive patients in 1990 also had a significantly lower percent predicted forced expiratory volume in 1 sec (FEV1) and weight percentile at follow-up, and they had an increased risk of continued P. aeruginosa respiratory infection and hospitalization for acute respiratory exacerbation in 1998. Among the other predictors of increased morbidity and mortality were lower baseline weight percentiles and number of CF-related hospitalizations during the baseline year. These findings confirm reports from previous smaller studies of outcomes among young children with CF, and highlight the potential to decrease the morbidity and mortality of young patients with CF through early intervention. Pediatr Pulmonol. 2002; 34:91,100. © 2002 Wiley-Liss, Inc. [source]

Race and sex differences and contribution of height: A study on bone size in healthy Caucasians and Chinese

Yuan-Yuan Zhang
Osteoporosis is characterized by a loss of bone strength, of which bone size (BS) is an important determinant. However, studies on the factors determining BS are relatively few. The present study evaluated the independent effects of height, age, weight, sex, and race on areal BS at the hip and spine, measured by dual-energy X-ray absorptiometry, while focusing on the differential contributions of height to BS across sex, race, and skeletal site. The subjects were aged 40 years or older, including 763 Chinese (384 males and 379 females) from Shanghai, People's Republic of China, and 424 Caucasians (188 males and 236 females) from Omaha, Nebraska. Basically, Caucasians had significantly larger BS than Chinese. After adjusting for height, age, and weight, the Chinese had similar spine BS, but significantly larger intertrochanter BS in both sexes and larger total hip BS in females compared with Caucasians. Males had significantly larger BS than females before and after adjustment in both ethnic groups. The effects of age, weight, and race varied, depending on skeletal site. As expected, height had major effects on BS variation in both sexes and races. Height tended to account for larger BS variation at the spine than at the hip (except for Chinese females), and larger BS variation in Caucasians than in Chinese of the same sex (except for the trochanter in females). We conclude that height is a major predictor for BS, and its contributions vary across sex, race, and skeletal site. Am. J. Hum. Biol. 17:568,575, 2005. © 2005 Wiley-Liss, Inc. [source]

Rheumatoid factor is the major predictor of increasing severity of radiographic erosions in rheumatoid arthritis: Results from the Norfolk Arthritis Register Study, a large inception cohort

M. Bukhari
Objective To identify the relative contributions of clinical and laboratory variables, determined at baseline, in predicting the deterioration of radiographic damage 5 years after presentation in patients with inflammatory polyarthritis. Methods Data from 439 subjects who sought primary care for inflammatory polyarthritis were analyzed. All subjects had paired radiographs, of which the first was obtained within 24 months of presentation and the second at 5 years after presentation. The contribution of baseline clinical and laboratory variables in predicting the degree of radiologic severity as judged by the Larsen score was assessed at both time points. Additionally, the role of these factors in predicting change after adjustment for baseline severity was also measured. Results By 5 years, 49% of subjects had evidence of erosions. The median Larsen score on the first film was 2 (interquartile range [IQR] 0,10) and the median score on the followup film was 7 (IQR 1,25). These corresponded to a median deterioration of 3 (IQR 0,14) in all subjects, whereas those subjects with evidence of erosions at first film showed a median deterioration of 15 (IQR 6,29) on followup. The rheumatoid factor (RF) status, C-reactive protein levels, the presence of nodules, and number of swollen joints at baseline were all predictive of radiographic severity at first film. Not surprisingly, the baseline radiographic score was a predictor of severity of deterioration. However, after adjusting for baseline severity, a high titer of RF (>1:160) was also an independent predictor of deterioration over 5 years: individuals with an initial RF at that level had a progression in their Larsen score that was 2.3 times (95% confidence interval 1.7,3.2) higher than that in the RF-negative individuals. Apart from this, only age had an independent effect, after adjusting for baseline severity, in predicting increasing radiographic joint damage. Conclusion High-titer RF is an important variable in predicting continuing severity of radiographic damage during the first 5 years after presentation with inflammatory polyarthritis. [source]

Economic Liberalization and the Antecedents of Top Management Teams: Evidence From Turkish ,Big' Business

Sibel Yamak
There has been an increased interest in the last two decades in top management teams (TMTs) of business firms. Much of the research, however, has been US-based and concerned primarily with TMT effects on organizational outcomes. The present study aims to expand this literature by examining the antecedents of top team composition in the context of macro-level economic change in a late-industrializing country. The post-1980 trade and market reforms in Turkey provided the empirical setting. Drawing upon the literatures on TMT and chief executive characteristics together with punctuated equilibrium models of change and institutional theory, the article develops the argument that which firm-level factors affect which attributes of TMT formations varies across the early and late stages of economic liberalization. Results of the empirical investigation of 71 of the largest industrial firms in Turkey broadly supported the hypotheses derived from this premise. In the early stages of economic liberalization the average age and average organizational tenure of TMTs were related to the export orientation of firms, whereas in later stages, firm performance became a major predictor of these team attributes. Educational background characteristics of teams appeared to be under stronger institutional pressures, altering in different ways in the face of macro-level change. [source]

Insulin resistance, diabetes and cardiovascular risk: approaches to treatment

Daniel E. Rosenberg
Abstract:, The prevalence of diabetes is increasing worldwide. Insulin resistance and diabetes mellitus are major predictors of cardiovascular ischaemic disease. Other risk factors for cardiovascular death including hypertension, dyslipidaemia, smoking and visceral obesity are especially lethal in diabetics. C-reactive protein, plasminogen activator inhibitor-1, matrix metalloproteinases and other emerging risk factors and their roles are continually being researched and discovered. Treatment of this syndrome must be aimed at lifestyle modification, glycaemic control and management of concomitant risk factors. Diet and exercise play a vital role in the treatment of diabetes and the metabolic syndrome. Weight reduction and increased physical activity will improve insulin resistance, hyperglycaemia, hypertension and dyslipidaemia. Hypertension management has been shown to be especially important in diabetics to prevent cardiovascular events. Likewise, multiple clinical trials show that reduction of cholesterol is even more vital in diabetics than the general population for risk reduction of coronary disease. There is a great deal of evidence that tight control of glycaemia is essential to treatment of this condition. There are a variety of available pharmacological agents available including metformin, insulin secretagogues, alpha-glucosidase inhibitors, thiazolidinediones and insulin. The mechanisms and side effects of these medications are discussed. As macrovascular disease is the major cause of morbidity and mortality, an early, aggressive, multi-factorial approach to treatment of the metabolic syndrome and diabetes is vital to prevent adverse cardiac outcomes. [source]

Central fat predicts deterioration of insulin secretion index and fasting glycaemia: 6-year follow-up of subjects at varying risk of Type 2 diabetes mellitus

A. D. Kriketos
Abstract Aims To examine the relationships between body composition and changes in fasting glycaemia, and in indices of insulin secretion and insulin action over 6 years in females with a family history of Type 2 diabetes with or without prior gestational diabetes (,at risk' group, AR) and control females (control group, C). Methods At baseline and at follow-up, an oral glucose tolerance test and dual energy X-ray absorptiometry assessment of body composition were performed. Indices of insulin resistance (HOMA R,) and insulin secretion (HOMA ,,) were obtained from fasting insulin and glucose concentrations. Results At baseline, the groups were similar for age, body mass index, fasting levels of plasma glucose and insulin, HOMA R, and HOMA ,,. Despite similar total body fatness, AR had significantly greater waist circumference and central fat (both P < 0.02) compared with C. At follow-up there was a significant increase in central adiposity only in AR, and the fasting plasma glucose (FPG) level was higher in AR compared with C (5.0 ± 0.2 vs. 4.3 ± 0.2 mmol/l, P = 0.02). This rise in plasma glucose in AR was related to a decline in HOMA ,, (r = 0.45, P = 0.0065). Both the baseline and the increments in total and central abdominal fat mass were associated with the time-related decline in HOMA ,,. Conclusions Six years after initial assessment, AR showed deterioration in FPG levels due predominantly to a decline in insulin secretion index without major change in insulin resistance index. Importantly, baseline body fatness (especially central adiposity), as well as increases in fatness with time, were the major predictors of the subsequent decline of insulin secretion index and the consequent rise in FPG. [source]

Prediction of Type 2 diabetes in healthy middle-aged men with special emphasis on glucose homeostasis.

Results from 22.5 years' follow-up
SUMMARY Aims To study the glucose disappearance rate and fasting blood glucose as predictors of Type 2 diabetes in a 22.5-year prospective follow-up of 1947 healthy non-diabetic men. Subjects and methods Of a cohort of 2014 Caucasian men, the 1947 who had both fasting blood glucose <,110 mg/dl and an intravenous glucose tolerance test were included. A number of other physiological parameters were also determined at baseline. Multivariate Cox regression analyses were used to investigate the possible significance of the glucose disappearance rate and fasting blood glucose as predictors of Type 2 diabetes. Results After 22.5 years' follow-up, 143 cases of Type 2 diabetes had developed. Glucose disappearance rate and fasting blood glucose were moderately correlated (r = ,0.32). Men in the lowest quartile of glucose disappearance rate and highest quartile of fasting blood glucose had markedly higher diabetes rates than all other men (P < 0.0001). After adjusting for each other, age, diabetes heredity, body mass index, physical fitness, triglycerides, cholesterol and blood pressure (Cox model), both glucose disappearance rate and fasting blood glucose remained major predictors of diabetes Conclusions Glucose disappearance rate and fasting blood glucose are, in spite of low intercorrelation, major long-term predictors of Type 2 diabetes in healthy non-diabetic Caucasian men. [source]

Mechanisms of Late Stent Malapposition After Primary Stenting in ST-Elevation Myocardial Infarction: A Subanalysis of the Selection Trial

Background: One of the major predictors of late stent malapposition (LSM) is primary stenting in acute myocardial infarction. However, mechanisms of LSM are still under debate. Methods: Patients with ST-elevation myocardial infarction (STEMI) and enrolled in the SELECTION trial (38 patients in the paclitaxel-eluting stent, PES, and 35 in the bare metal stent, BMS, cohort) were retrospectively analyzed to evaluate LSM, by means of intravascular ultrasound (IVUS) data recorded at the index and 7-month follow-up procedures. Results: Stent malapposition was documented in 21 lesions in 21 patients (28.8%): in 8 of these 21 patients (38.1%) it was LSM. Although statistical significance was not reached, LSM was more frequent after PES than BMS implantation (15.8% vs. 5.7%). LSM was mainly located within the body of the stent (62.5% of the cases). At the LSM segment, a significant increase of vessel area (19.2 ± 3.3 mm2 vs. 21.9 ± 5.3 mm2, P = 0.04) and a reduction of plaque area (12.6 ± 4.6 mm2 vs. 9.1 ± 3.9 mm2, P = 0.04) were observed at IVUS between the index and follow-up procedure. Conclusions: After primary stenting for STEMI, LSM seems to be more frequent after PES rather than BMS implantation. In the STEMI setting, possible mechanisms leading to LSM include positive remodeling and plaque mass decrease. [source]

Employee creativity in U.S. and Lithuanian nonprofit organizations

Kristina Jaskyte
This article reports findings from a study designed to test a model of creativity in the United States and Lithuania. Five independent variables were derived from the creativity literature: perceived leadership behaviors, organizational norms for creativity, group climate, job characteristics, and motivational orientation. They were used to predict creativity in a sample of 201 employees of nonprofit organizations. The results differed for the two countries. Interestingly, while in the United States organizational norms for creativity, extrinsic motivation, and hierarchical level were related to employee creativity, in Lithuania intrinsic motivation and education constituted major predictors of creativity. Based on the study results, I suggest practical implications for nonprofit managers on how to capitalize on their employees' creativity. [source]

Section Editor: Aad Tibben, email: Quality of life and psychological distress in patients with Peutz,Jeghers syndrome

MGF Van Lier
van Lier MGF, Mathus-Vliegen EMH, van Leerdam ME, Kuipers EJ, Looman CWN, Wagner A, Vanheusden K. Quality of life and psychological distress in patients with Peutz,Jeghers syndrome. Little is known about psychological distress and quality of life (QoL) in patients with Peutz,Jeghers syndrome (PJS), a rare hereditary disorder. We aimed to assess QoL and psychological distress in PJS patients compared to the general population, and to evaluate determinants of QoL and psychological distress in a cross-sectional study. PJS patients completed a questionnaire on QoL, psychological distress, and illness perceptions. The questionnaire was returned by 52 patients (85% response rate, 56% females, median age 44.5 years). PJS patients reported similar anxiety (p = 0.57) and depression (p = 0.61) scores as the general population. They reported a lower general health perception (p = 0.003), more limitations due to emotional problems (p = 0.045) and a lower mental well-being (p = 0.036). Strong beliefs in negative consequences of PJS on daily life, a relapsing course of the disease, strong emotional reactions to PJS, and female gender were major determinants for a lower QoL. PJS patients experience a similar level of psychological distress as the general population, but a poorer general health perception, more limitations due to emotional problems, and a poorer mental QoL. Illness perceptions and female gender were major predictors for this lower QoL. These results may help to recognize PJS patients who might benefit from psychological support. [source]