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Determinant Factors (determinant + factor)
Selected AbstractsAdaptive Offspring Sex Ratio Depends on Male Tail Length in the GuppyETHOLOGY, Issue 11 2006Kenji Karino A biased sex ratio in a brood is considered to be an adaptive strategy under certain circumstances. For example, if the expected reproductive success of one sex is greater than that of the other, parents should produce more offspring of the former sex than the latter. A previous study has documented that in the guppy, Poecilia reticulata, the female offspring of males possessing proportionally longer tails exhibit smaller body sizes and show decreased reproductive outputs than those of males having shorter tails. On the other hand, the total lengths of the male offspring of the long-tailed males are larger because of their longer tails; consequently, they exhibit greater sexual attractiveness to females. Therefore, it has been hypothesized that this asymmetry in the expected reproductive success between the male and female offspring of long-tailed males may result in a biased sex ratio that is dependent on the tail lengths of their fathers. This hypothesis was tested in the present study. The results showed that the females that mated with long-tailed males produced more male offspring than those that mated with short-tailed males. Logistic regression analysis showed that the ratio of tail length to the standard length of the fathers is a determinant factor of the sex of their offspring. These results suggest that the manipulation of the offspring sex ratios by parents enhances the overall fitness of the offspring. [source] Depletion of immature B,cells during Trypanosoma cruzi infection: involvement of myeloid cells and the cyclooxygenase pathwayEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 6 2005Elina Zuniga Abstract The ability of a microorganism to elicit or evade B,cell responses represents a determinant factor for the final outcome of an infection. Although pathogens may subvert humoral responses at different stages of B,cell development, most studies addressing the impact of an infection on the B,cell compartment have focused on mature B,cells within peripheral lymphoid organs. Herein, we report that a protozoan infection, i.e. a Trypanosoma cruzi infection, induces a marked loss of immature B,cells in the BM, which also compromises recently emigrated B,cells in the periphery. The depletion of BM immature B,cells is associated with an increased rate of apoptosis mediated by a parasite-indirect mechanism in a Fas/FasL-independent fashion. Finally, we demonstrated that myeloid cells play an important role in B,cell depletion, since CD11b+ BM cells from infected mice secrete a product of the cyclooxygenase pathway that eliminates immature B,cells. These results highlight a previously unrecognized maneuver used by a protozoan parasite to disable B,cell generation, limiting host defense and favoring its chronic establishment. [source] Lack of correlation between canine heart rate and body size in veterinary clinical practiceJOURNAL OF SMALL ANIMAL PRACTICE, Issue 8 2010L. Ferasin Objectives: An association between heart rate (HR) and bodyweight has been reported in dogs and it is common belief that small breeds of dog exhibit higher HR than large breeds. The first aim of this study was to test the null hypothesis that, in veterinary clinical practice, bodyweight does not affect HR measured in healthy dogs. A second objective of this investigation was to assess whether other variables, such as gender, breed morphology, age and demeanour, may have a significant effect on dog's HR measured in a clinical setting. Methods: The investigation was performed via two different studies: a retrospective analysis performed on 243 electrocardiogram recordings and a prospective study based on 153 standardised clinical examinations. Results: The two separate studies did not show any significant correlation between HR and bodyweight (P=0·5705 and P=0·4682, respectively). Subject's breed morphology and gender did not appear to affect HR measured under these circumstances. However, dogs under the age of one year seem to have significantly higher HRs than older dogs (P < 0·05). Finally, subject's demeanour was also found to have a significant influence on HR; lower values were recorded in relaxed dogs, and higher rates were documented in excited, nervous dogs (P < 0·05). Clinical Significance: Normal HR could be erroneously interpreted as bradycardia or tachycardia if bodyweight was to be considered a determinant factor. Instead, HR in healthy dogs undergoing routine clinical examination is related to their demeanour or age, if younger than 12 months, but does not appear to be related to bodyweight. [source] The Occurrence of the psbS Gene Product in Chlamydomonas reinhardtii and in Other Photosynthetic Organisms and Its Correlation with Energy Quenching,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 6 2008Giulia Bonente To avoid photodamage, photosynthetic organisms have developed mechanisms to evade or dissipate excess energy. Lumen overacidification caused by light-induced electron transport triggers quenching of excited chlorophylls and dissipation of excess energy into heat. In higher plants participation of the PsbS protein as the sensor of low lumenal pH was clearly demonstrated. Although light-dependent energy quenching is a property of all photosynthetic organisms, large differences in amplitude and kinetics can be observed thus raising the question whether a single common mechanism is in action. We performed a detailed study of PsbS expression/accumulation in Chlamydomonas reinhardtii and investigated its accumulation in other algae and plants. We showed that PsbS cannot be detected in Chlamydomonas under a wide range of growth conditions. Overexpression of the endogenous psbs gene showed that the corresponding protein could not be addressed to the thylakoid membranes. Survey of different unicellular green algae showed no accumulation of anti-PsbS reactive proteins differently from multicellular species. Nevertheless, some unicellular species exhibit high energy quenching activity, suggesting that a PsbS-independent mechanism is activated. By correlating growth habitat and PsbS accumulation in different species, we suggest that during the evolution the light environment has been a determinant factor for the conservation/loss of the PsbS function. [source] Should being aged over 70 years hinder penile prosthesis implantation?BJU INTERNATIONAL, Issue 6 2009Amr Al-Najar OBJECTIVE To assess the satisfaction profiles following penile prosthesis surgery in patients with erectile dysfunction (ED) in their seventh decade of life. PATIENTS AND METHODS In all, 174 patients received, for the first time, a penile prosthesis between 1990 and 2007 in our department. Among these, 35 patients were aged ,70 years at prosthesis implantation. Of these, 18 patients were still alive at the time of follow-up. Using a telephone survey, patients were asked to answer the Erectile Dysfunction Inventory of Treatment Satisfaction (EDITS) as well as the International Index of Erectile Dysfunction (IIEF). Another question in the survey was developed by the authors based on a comprehensive review of the literature, which assessed the usefulness of the device for the patient and the degree of their usage. This was formulated as follows: How many times per 2 weeks do you have a sexual intercourse? RESULTS In all, 15 of 18 patients were either very or somewhat satisfied (83%). At follow-up 11 out of 15 (73%) patients were using their prosthesis regularly. The mean IIEF and EDITS scores were 21.80 and 75.20, respectively. CONCLUSION A penile prosthesis remains a highly promising treatment in older patients with a similar satisfaction rate to those published for younger patients. Thus, the motivation of the patient and not the age of the patient should be the main determinant factor in this surgical procedure. [source] A review of determinant factors of environmental proactivityBUSINESS STRATEGY AND THE ENVIRONMENT, Issue 2 2006Javier González-Benito Abstract This paper reviews the literature in order to identify the determinant factors of a company's environmental proactivity. It starts by arguing that environmental proactivity can be manifested through diverse practices and strategies and goes on to comment upon several variables that seem to influence the decision to implement such strategies. Some of these variables depict internal company features and others describe the general environment in which operations are carried out. Stakeholders' pressure is distinguished as a central determinant factor and it is argued that all the other variables affect either the intensity of this pressure or the company's capacity to perceive it. All the factors identified herein should be taken into account, at least as control variables, in those studies aiming at explaining and contextualizing environmental strategies. Copyright © 2006 John Wiley & Sons, Ltd and ERP Environment. [source] Maternal plasma level of antimicrobial peptide LL37 is a major determinant factor of neonatal plasma LL37 levelACTA PAEDIATRICA, Issue 6 2010A Mandic Havelka Abstract Aim:, To determine cathelicidin antimicrobial peptide LL37subcellular distribution in cord neutrophils and normal plasma LL37 levels in mothers and neonates, relate them to delivery mode and relevant biochemical markers, including 25-OHvitamin D [25(OH)D] as this molecules increases cathelicidin gene expression. Methods:, A total of 115 infants were included, n = 68 with normal delivery and n = 47 with elective Caesarean section (C-section), a subset of these being 50 mother,infant pairs. Biomarkers were determined in maternal and cord blood. Subcellular peptide LL37 distribution was analysed with immunoelectron microscopy. Results:, Cord plasma LL37 levels were three-times higher after normal delivery compared with C-section. A highly significant correlation was observed between maternal and cord plasma LL37 levels, regardless of delivery mode. No relationship was found between LL37 and 25(OH)D levels. Neutrophils from cord blood after normal delivery contained 10-times more cytoplasmatic cathelicidin peptide compared with corresponding cells after C-section where a strict granular localization was found. Conclusion:, These data are consistent with a placental transfer of LL37 and identifies maternal stores as the critical factor determining neonatal plasma LL37 level. An additional enhancement of neonatal cathelicidin mobilization and release is connected to normal delivery stress. [source] Mycobacterial infection in a series of 1261 renal transplant recipientsCLINICAL MICROBIOLOGY AND INFECTION, Issue 6 2003J. A. Queipo Objective To describe the incidence and clinical characteristics of mycobacterial infection in renal transplant recipients. Methods We retrospectively analyzed the cases of mycobacterial infection in a series of 1261 renal transplants carried out in our Unit of Renal Transplantation from 1980 to 2000. Demographic parameters and clinical antecedents such as age, cause of end-stage renal disease, time of follow-up of the graft, previous renal function and type of immunosuppression were considered. Moreover, the clinical onset, diagnostic tools, treatment policy and evolution were studied. The pathogenesis of the different types of mycobacteria isolated was also analyzed. Diagnosis was made with the Ziehl,Neelsen staining method. Culture was performed by the conventional Löwenstein,Jensen method and the Bactec-460 radiometric method. Results We found mycobacterial infection in 27 patients (2.1%), due to Mycobacterium tuberculosis in 20 cases, M. kansasii in five patients, and M. fortuitum in two patients. The mean elapsed time from the renal transplant was 20.5 months; the infection appeared in 18 patients during the first eight months after transplantation. The clinical onset was pulmonary infection in 17 cases (12 M. tuberculosis and five M. kansasii); five had urinary symptoms (three M. tuberculosis and two M. fortuitum); three cases of M. tuberculosis infection had abdominal symptoms; another one began with a perineal tuberculous abscess; the rest of the patients were asymptomatic. The types of specimen on which microbiological identification was carried out were, in decreasing order: sputum and/or bronchial washing/pleural aspiration, urine, feces, gastric and peritoneal fluids, bone marrow and blood. The first-line drug isoniazid had the highest resistance index in the susceptibility test. Clinical dissemination was observed in eight patients, four of whom died. Another three patients had a significant impairment in renal function, and in one of these patients an allograft nephrectomy was necessary due to a severe septic syndrome. Conclusions Mycobacterial infection, mainly by M. tuberculosis, has an important impact on kidney transplant recipients, particularly during the first year after surgery. Diagnosis often presents some difficulties, and a delay in treatment represents a determinant factor for the evolution, with a risk of death or permanent damage in renal function. Therefore, early diagnosis is mandatory. When the Mantoux reaction is positive, antituberculous prophylaxis seems advisable. [source] Thermodynamic Study of ,H Complexes in Nucleophilic Aromatic Substitution Reactions: Relative Stabilities of Electrochemically Generated RadicalsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 14 2008Iluminada Gallardo Abstract The mechanism for the electrochemical oxidation of ,H complexes, such as 1-hydro-1-alkoxy/sulfoxy or -fluoro-2,4-dinitro/2,4,6-trinitrocyclohexadienyl anions, has been widely studied by means of cyclic voltammetry and controlled-potential electrolysis. Previous studies have shown that the electrochemical oxidation of ,H complexes, formed by the addition of carbon or nitrogen nucleophiles followed by a two electron mechanism, corresponding to the formal elimination of the hydride anion (nucleophilic aromatic substitution of hydrogen mechanism, the NASH mechanism). For these ,H complexes (Nu, = OH,, ,OR, ,SR, ,F), the electrochemical reaction takes place by a one-electron mechanism and is followed by the radical elimination of the leaving group with the consequent recovery of the starting material. This mechanism is similar to that proposed for the electrochemical oxidation of ,X complexes (nucleophilic aromatic substitution of a heteroatom, the NASX mechanism). The operating mechanism in each case, the NASH or NASX, can be rationalized in terms of thermodynamics. The standard potentials of the , complex and/or the leaving group as well as the bond dissociation energies (BDEs) are determinant factors. This study has not led to a significant improvement in the electrochemical preparation of aromatic-substituted compounds, but does help to understand and predict the usefulness or uselessness of using the nucleophilic aromatic substitution route to obtain a desired product. Finally, the current approach extends the electrochemical methodology to different chemical fields, for example, to general nondestructive methods for the detection, identification, and quantification of either organic pollutants or explosives in different solvents. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Influence of psychosocial factors on the development of sleep bruxism among childrenINTERNATIONAL JOURNAL OF PAEDIATRIC DENTISTRY, Issue 5 2009JUNIA M. SERRA-NEGRA Background., Bruxism is described as an orofacial parafunction that affects both children and adults. The maintenance of the childhood habit into adulthood may compromise health. As there are few studies on this issue, there is a need for further research on sleep bruxism among children. Aim., The aim of this study was to assess the prevalence of sleep bruxism in children and the influence of psychosocial factors. Methods., A cross-sectional study was carried out on 652 randomly selected children aged 7,10 years at public and private schools in Belo Horizonte, Brazil. The instruments used were: questionnaire for parents, Child Stress Scale, and the scales on neuroticism and responsibility from the prevalidated Big Five Questionnaire for Children. Psychological tests were administered and evaluated by psychologists. Sleep bruxism among children was reported by parents. The Social Vulnerability Index from the city hall database was used to determine the social classification of the families. The chi-squared test, binary and multivariate logistic regressions were used, with the significance level set at 5%. Results., A 35.3% prevalence of bruxism was found. No association was found between bruxism and stress, gender, age, or social vulnerability. The adjusted logistic model determined that children with high levels of neuroticism (OR = 1.9, CI 1.3,2.6) and responsibility (OR = 2.2, CI 1.0,5.0) are twice as likely to have the habit of sleep bruxism when compared to those who have low levels of these personality traits. Conclusions., A high degree of responsibility and neuroticism, which are individual personality traits, are determinant factors for the development of sleep bruxism among children. [source] Individual difference in the number of chewing strokes and its determinant factorsJOURNAL OF ORAL REHABILITATION, Issue 2 2006T. UEDA summary, This study was carried out to clarify the distribution and individual variation of the number of chewing strokes before last swallowing (NCS), as well as to assess the factors that affect NCS, when dentulous adults masticate the same type of food. NCS was measured in 75 dentulous adults using gummy candies. Measurements were repeated five times to obtain the average and variation. Moreover, the correlation of NCS with various physiological factors (lateral width and vertical distance of chewing loop, angle of opening and closing path, opening and closing time, occlusal time, masticatory performance, number of occlusal contact points, occlusal contact area, occlusal force, flow rate of whole saliva and viscosity of whole saliva) and 28 personality factors were analysed by both of the single variate analysis and the multivariate analysis. The results showed that the average NCS was 41·0 ± 16·0, and the coefficient of variation was 0·090 ± 0·040. Additionally, the correlation between NCS and each factor was investigated, and found that any of these factors did not function as a single determinant for NCS. Following, determinant factors were further examined by the stepwise method of linear multiple regression analysis. From these analysis we found that when opening and closing time and four personality factors were combined, they were significantly involved in determining NCS (P < 0·01). Therefore, we conclude that individual NCS until last swallowing is not determined by a sole, specific physiological factor but is affected by multiple factors including personality. [source] E-selectin and L-selectin polymorphisms in patients with periodontitisJOURNAL OF PERIODONTAL RESEARCH, Issue 1 2009B. Houshmand Background amd Objective:, Periodontitis is a multifactorial disease in which environmental and genetic determinant factors contribute to individual subject's susceptibility. A DNA polymorphism in the regulating region of adhesion molecule genes is suggested to modulate the molecule's physiological effects. The aim of this study was to investigate the genetic association between the E-selectin Ser128Arg and L-selectin Phe206Leu polymorphisms and periodontitis. Material and Methods:, DNA was isolated from the whole blood of 88 patients with periodontitis and 139 healthy individuals. All samples were genotyped for the E-selectin Ser128Arg and L-selectin Phe206Leu polymorphisms using the polymerase chain reaction with sequence specific primers. Results:, Our findings revealed a significant difference in the Ser128Arg polymorphism of E-selectin, but not in the L-selectin polymorphism, between periodontal patients and controls. The 128Arg allele was present more frequently in patients than in healthy individuals (31.25% vs. 12.2%, p < 0.0001). In addition, there was an association between the presence of the 128Arg allele and periodontitis (odds ratio 2.9; 95% confidence interval: 1.75,4.4, p < 0.0001). No significant association was found between the polymorphisms tested and the subgroups of periodontal disease (i.e. chronic periodontitis and aggressive periodontitis). Conclusion:, The findings of this study showed that the Ser128Arg polymorphism of E-selectin might contribute to the susceptibility of Iranian individuals to periodontitis. [source] Determining factors of academic library Web site usageJOURNAL OF THE AMERICAN SOCIETY FOR INFORMATION SCIENCE AND TECHNOLOGY, Issue 14 2007John H. Heinrichs This study develops three alternative models of academic library Web site usage based on the Technology Acceptance Model (TAM). The three alternative models depict relationships among various intrinsic and extrinsic determinant factors of an academic library's Web site usage. The four factors included in the models are perceived ease-of-use, perceived usefulness, service functionality, and task functionality. These four factors are hypothesized to affect directly or indirectly both factors of satisfaction and intention-to-use. LISREL analysis using survey data shows that the best-fit model is the "Dual Mediation Impact" Model. Research and managerial implications for the academic library are discussed. Future research directions and limitations also are provided. [source] Synthetic hydrotalcites from different routes and their application as catalysts and gas adsorbents: a reviewAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 9 2009M. R. Othman Abstract In this paper, widely accepted methods of hydrotalcite preparation such as co-precipitation, urea hydrolysis, hydrothermal, sol,gel, microwave irradiation, steam activation and solvothermal have been selected and reviewed. Our review indicates that the nature of the divalent cations, the synthesis method, the calcination temperature and the nature of the interlayer species are determinant factors in shaping the surface properties of the layered double hydoxides. The basic strength of the surface base site and structural changes produced in the mixed oxides can be adjusted conveniently by varying the Al content during the synthesis. The combination of sol,gel with microwave irradiation during the gelling and crystallization steps has also been found to increase the surface area of the hydrotalcite-like compound. Copyright © 2009 John Wiley & Sons, Ltd. [source] A study of determinant factors of stakeholder environmental pressure perceived by industrial companiesBUSINESS STRATEGY AND THE ENVIRONMENT, Issue 3 2010Javier González-Benito Abstract Although several articles have studied the effect that stakeholder pressure has on the environmental behavior of firms, little research has attempted to identify the contingencies that explain such pressure. This article investigates the effects of six relevant variables on stakeholder environmental pressure perceived by industrial companies: size, internationalization, location of manufacturing activities, position in the supply chain, industrial sector, and managerial values and attitudes. The effect is theoretically determined by distinguishing between pressure intensity and perception capacity and empirically tested with a sample of 186 Spanish manufacturers. The analyses reveal two dimensions of stakeholder pressure, governmental and nongovernmental, and show that variables such as environmental awareness among managers, internationalization, industrial sector and company size play important roles in determining both dimensions. Copyright © 2008 John Wiley & Sons, Ltd and ERP Environment. [source] A review of determinant factors of environmental proactivityBUSINESS STRATEGY AND THE ENVIRONMENT, Issue 2 2006Javier González-Benito Abstract This paper reviews the literature in order to identify the determinant factors of a company's environmental proactivity. It starts by arguing that environmental proactivity can be manifested through diverse practices and strategies and goes on to comment upon several variables that seem to influence the decision to implement such strategies. Some of these variables depict internal company features and others describe the general environment in which operations are carried out. Stakeholders' pressure is distinguished as a central determinant factor and it is argued that all the other variables affect either the intensity of this pressure or the company's capacity to perceive it. All the factors identified herein should be taken into account, at least as control variables, in those studies aiming at explaining and contextualizing environmental strategies. Copyright © 2006 John Wiley & Sons, Ltd and ERP Environment. [source] Application of new homologous in vitro bioassays for human lactogens to assess the actual bioactivity of human prolactin isoforms in hyperprolactinaemic patientsCLINICAL ENDOCRINOLOGY, Issue 2 2006Alfredo Leaños-Miranda Summary Background, ,Prolactin (PRL) plays a central role in mammary gland development and lactation. Due to its molecular heterogeneity, measurement of PRL immunoreactivity does not necessarily reflect its intrinsic bioactivity. For many years the Nb2 rat lymphoma cell bioassay has been the only reference bioassay for human lactogens. This bioassay, however, does not always correlate with the clinical features found in some patients exhibiting normal or elevated immunoreactive serum PRL concentrations. Objectives, ,(1) To determine the concentrations of bioactive PRL in serum samples from individuals with normoprolactinaemia or with different forms of hyperprolactinaemia using two recently described homologous in vitro bioassays (i.e. a transcriptional bioassay in HEK-293 cells and a proliferation assay in Ba/F3 cells); and (2) to compare these results with those generated by the classical Nb2 cell bioassay. Design, ,Cross-sectional study. Setting, ,An institutional biomedical research laboratory. Participants, ,Ten patients with symptomatic hyperprolactinaemia due to prolactinoma, 11 patients with asymptomatic hyperprolactinaemia and macroprolactinaemia, and nine normal women. Main outcome measures, ,Measurement of immunoreactive and bioactive concentrations of serum PRL. Results, ,Samples from normal women and patients with tumoral hyperprolactinaemia due to prolactinoma exhibited similar within-group concentration values of bioactive and immunoreactive serum PRL when tested by the three bioassays and the immunoradiometric assay employed. By contrast, measurement of bioactive PRL in samples from patients with macroprolactinaemia revealed that macroprolactin was poorly active in the homologous receptor bioassays, while it was more active in the Nb2 bioassay. Conclusions, ,The reduced bioactivity of PRL in patients with macroprolactinaemia may further explain the absence of clinical features of hyperprolactinaemia in these individuals. In addition, our findings indicate that species-specificity and sensitivity of the bioassays are determinant factors in the measurement of the intrinsic biological activity of circulating PRL. [source] | ||||||||||||||||