827 resultados para Factorial validity


Relevância:

10.00% 10.00%

Publicador:

Resumo:

There is no doubt about the importance of service quality as a factor of businesses' success, but to measure this quality has proved to be a challenge when one considers different environmental contexts. Given this, the main goal of this paper was to test two measurement scales of perceived set-vice quality. The comparison between Service Quality scale (Servqual) and Retail Set-vice Quality (RSQ) was conducted by means of a survey with 351 participants, clients of a home center stores chain located in the city of Sao Paulo. The data were analyzed using both exploratory and confirmatory factor analysis. As a result, both scales demonstrated acceptable levels of reliability and validity However; the RSQ demonstrated a better performance in the nomological test since it was able to explain 43% of the loyalty towards the retailer; while the Servqual scale explained only 11%.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A considerable portion of Brazil's commercial eucalypt plantations is located in areas Subjected to periods of water deficit and grown in soils with low natural fertility, particularly poor In potassium. Potassium is influential in controlling water relations of plants. The objective of this study was to verify the influence of potassium fertilization and soil water potential (psi(w)) oil the dry matter production and oil water relations Of eucalypt seedlings grown under greenhouse conditions. the experimental units were arranged in 4x4x2 randomized blocks factorial design, as follow: four species of Eucalyptus (Eucalyptus grandis, Eucalyptus urophylla, Eucalyptus camaldulensis and hybrid Eucalyptus grandis x Eucalyptus urophylla), four dosages of K (0, 50, 100 and 200 mg dm(-3)) and two soil water potentials (-0.01 M Pa and -0.1 M Pa). Plastic containers with 15 cm diameter and 18 cm height, with Styrofoam base, containing 3.0 dm(3) of soil and two plants per container were used. Soil water potential was kept at -0.01 MPa for 40 days after seeding. Afterward, the experimental units were divided into two groups: in one group the potential was kept at 0.01 MPa, and in the other one, at -0.10 MPa. Sol I water potential was control led gravimetrically twice a day with water replacement until the desired potential was reestablished. A week before harvesting, the leaf water potential (psi), the photosynthetic rate (A), the stomatal conductance (gs) and the transpiration rate were evaluated. The last week before harvesting, the mass of the containers was recorded daily before watering to determine the consumption of water by the plants. After harvesting, total dry matter and leaf area were evaluated. the data were Submitted to analysis of variance, to Tukey's tests and regression analyses. The application of K influenced A, gs and the transpiration rate. Plants deficient in K showed lower A and higher Us and transpiration rates. There were no statistical differences in A, gs and transpiration rates ill plants with and Without water deficit. The addition of K reduced the consumption of water per unit of leaf area and, in general, plants submitted to water deficit presented a lower consumption of water.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Large-conductance Ca(2+)-activated K(+) channels (BK) play a fundamental role in modulating membrane potential in many cell types. The gating of BK channels and its modulation by Ca(2+) and voltage has been the subject of intensive research over almost three decades, yielding several of the most complicated kinetic mechanisms ever proposed. A large number of open and closed states disposed, respectively, in two planes, named tiers, characterize these mechanisms. Transitions between states in the same plane are cooperative and modulated by Ca(2+). Transitions across planes are highly concerted and voltage-dependent. Here we reexamine the validity of the two-tiered hypothesis by restricting attention to the modulation by Ca(2+). Large single channel data sets at five Ca(2+) concentrations were simultaneously analyzed from a Bayesian perspective by using hidden Markov models and Markov-chain Monte Carlo stochastic integration techniques. Our results support a dramatic reduction in model complexity, favoring a simple mechanism derived from the Monod-Wyman-Changeux allosteric model for homotetramers, able to explain the Ca(2+) modulation of the gating process. This model differs from the standard Monod-Wyman-Changeux scheme in that one distinguishes when two Ca(2+) ions are bound to adjacent or diagonal subunits of the tetramer.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

We measure directed flow (v(1)) for charged particles in Au + Au and Cu + Cu collisions at root s(NN) = 200 and 62.4 GeV, as a function of pseudorapidity (eta), transverse momentum (p(t)), and collision centrality, based on data from the STAR experiment. We find that the directed flow depends on the incident energy but, contrary to all available model implementations, not on the size of the colliding system at a given centrality. We extend the validity of the limiting fragmentation concept to v(1) in different collision systems, and investigate possible explanations for the observed sign change in v(1)(p(t)).

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Background: Bipolar Disorder (BD) is a chronic, recurrent and highly prevalent illness. Despite the need for correct diagnosis to allow proper treatment, studies have shown that reaching a diagnosis can take up to ten years due to the lack of recognition of the broader presentations of BD. Frequent comorbidities with other psychiatric disorders are a major cause of misdiagnosis and warrant thorough evaluation. Methods/Design: ESPECTRA (Occurrence of Bipolar Spectrum Disorders in Eating Disorder Patients) is a single-site cross-sectional study involving a comparison group, designed to evaluate the prevalence of bipolar spectrum in an eating disorder sample. Women aged 18-45 years will be evaluated using the SCID-P and Zurich criteria for diagnosis and the HAM-D, YOUNG, SCI-MOODS, HCL-32, BIS-11, BSQ, WHOQoL and EAS instruments for rating symptoms and measuring clinical correlates. Discussion: The classificatory systems in psychiatry are based on categorical models that have been criticized for simplifying the diagnosis and leading to an increase in comorbidities. Some dimensional approaches have been proposed aimed at improving the validity and reliability of psychiatric disorder assessments, especially in conditions with high rates of comorbidity such as BD and Eating Disorder (ED). The Bipolar Spectrum (BS) remains under-recognized in clinical practice and its definition is not well established in current diagnostic guidelines. Broader evaluation of psychiatric disorders combining categorical and dimensional views could contribute to a more realistic understanding of comorbidities and help toward establishing a prognosis.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Background and Purpose: Several different methods of teaching laparoscopic skills have been advocated, with virtual reality surgical simulation (VRSS) being the most popular. Its effectiveness in improving surgical performance is not a consensus yet, however. The purpose of this study was to determine whether practicing surgical skills in a virtual reality simulator results in improved surgical performance. Materials and Methods: Fifteen medical students recruited for the study were divided into three groups. Group I (control) did not receive any VRSS training. For 10 weeks, group II trained basic laparoscopic skills (camera handling, cutting skill, peg transfer skill, and clipping skill) in a VRSS laparoscopic skills simulator. Group III practiced the same skills and, in addition, performed a simulated cholecystectomy. All students then performed a cholecystectomy in a swine model. Their performance was reviewed by two experienced surgeons. The following parameters were evaluated: Gallbladder pedicle dissection time, clipping time, time for cutting the pedicle, gallbladder removal time, total procedure time, and blood loss. Results: With practice, there was improvement in most of the evaluated parameters by each of the individuals. There were no statistical differences in any of evaluated parameters between those who did and did not undergo VRSS training, however. Conclusion: VRSS training is assumed to be an effective tool for learning and practicing laparoscopic skills. In this study, we could not demonstrate that VRSS training resulted in improved surgical performance. It may be useful, however, in familiarizing surgeons with laparoscopic surgery. More effective methods of teaching laparoscopic skills should be evaluated to help in improving surgical performance.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Background: Various neuroimaging studies, both structural and functional, have provided support for the proposal that a distributed brain network is likely to be the neural basis of intelligence. The theory of Distributed Intelligent Processing Systems (DIPS), first developed in the field of Artificial Intelligence, was proposed to adequately model distributed neural intelligent processing. In addition, the neural efficiency hypothesis suggests that individuals with higher intelligence display more focused cortical activation during cognitive performance, resulting in lower total brain activation when compared with individuals who have lower intelligence. This may be understood as a property of the DIPS. Methodology and Principal Findings: In our study, a new EEG brain mapping technique, based on the neural efficiency hypothesis and the notion of the brain as a Distributed Intelligence Processing System, was used to investigate the correlations between IQ evaluated with WAIS (Whechsler Adult Intelligence Scale) and WISC (Wechsler Intelligence Scale for Children), and the brain activity associated with visual and verbal processing, in order to test the validity of a distributed neural basis for intelligence. Conclusion: The present results support these claims and the neural efficiency hypothesis.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

PURPOSE most people with mental disorders receive treatment in primary care. The charts developed by the Dartmouth Primary Care Cooperative Research Network (COOP) and the World Organization of National Colleges, Academies, and Academic Associations of General Practitioners/Family Physicians (WONCA) have not yet been evaluated as a screen for these disorders, using a structured psychiatric interview by an expert or considering diagnoses other than depression. We evaluated the validity and feasibility of the COOP/WONCA Charts as a mental disorders screen by comparing them both with other questionnaires previously validated and with the assessment of a mental health specialist using a structured diagnostic interview. METHODS We trained community health workers and nurse assistants working in a collaborative mental health care model to administer the COOP/WONCA Charts, the 20-item Self-Reporting Questionnaire (SRQ-20), and the World Health Organization Five Well-Being Index (WHO-5) to 120 primary care patients. A psychiatrist blinded to the patients' results on these questionnaires administered the SCID, or Structured Clinical Interview for the DSM-IV (Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition). RESULTS The area under the receiver operating characteristic curve was at least 0.80 for single items, a 3-item combination, and the total score of the COOP/WONCA Charts, as well as for the SRQ-20 and the WHO-5, for screening both for all mental disorders and for depressive disorders. The accuracy, sensitivity, specificity, and positive and negative predictive values of these measures ranged between 0.77 and 0.92. Community health workers and nurse assistants rated the understandability, ease of use, and clinical relevance of all 3 questionnaires as satisfactory. CONCLUSIONS One-time assessment of patients with the COOP/WONCA Charts is a valid and feasible option for screening for mental disorders by primary care teams.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Background: Cerebral palsy (CP) patients have motor limitations that can affect functionality and abilities for activities of daily living (ADL). Health related quality of life and health status instruments validated to be applied to these patients do not directly approach the concepts of functionality or ADL. The Child Health Assessment Questionnaire (CHAQ) seems to be a good instrument to approach this dimension, but it was never used for CP patients. The purpose of the study was to verify the psychometric properties of CHAQ applied to children and adolescents with CP. Methods: Parents or guardians of children and adolescents with CP, aged 5 to 18 years, answered the CHAQ. A healthy group of 314 children and adolescents was recruited during the validation of the CHAQ Brazilian-version. Data quality, reliability and validity were studied. The motor function was evaluated by the Gross Motor Function Measure (GMFM). Results: Ninety-six parents/guardians answered the questionnaire. The age of the patients ranged from 5 to 17.9 years (average: 9.3). The rate of missing data was low(< 9.3%). The floor effect was observed in two domains, being higher only in the visual analogue scales (<= 35.5%). The ceiling effect was significant in all domains and particularly high in patients with quadriplegia (81.8 to 90.9%) and extrapyramidal (45.4 to 91.0%). The Cronbach alpha coefficient ranged from 0.85 to 0.95. The validity was appropriate: for the discriminant validity the correlation of the disability index with the visual analogue scales was not significant; for the convergent validity CHAQ disability index had a strong correlation with the GMFM (0.77); for the divergent validity there was no correlation between GMFM and the pain and overall evaluation scales; for the criterion validity GMFM as well as CHAQ detected differences in the scores among the clinical type of CP (p < 0.01); for the construct validity, the patients' disability index score (mean: 2.16; SD: 0.72) was higher than the healthy group ( mean: 0.12; SD: 0.23)(p < 0.01). Conclusion: CHAQ reliability and validity were adequate to this population. However, further studies are necessary to verify the influence of the ceiling effect on the responsiveness of the instrument.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The objective of this study was to evaluate the effect of a polyclonal antibody preparation (PAP) against specific ruminal bacteria on the in situ degradability of dry-grounded maize grain (DMG), high moisture maize silage (HMMS) starch and citrus pulp (CiPu) pectin. Nine ruminally cannulated cows were used in a 3 x 3 Latin square design, replicated three times in a factorial arrangement of treatments of two rumen modifiers represented by monensin and PAP plus a control group, and the three energy sources (DMG, HMMS and CiPu). Each period had 21 days, where 16 were used for adaptation to treatment and five for data collection. The group treated with PAP showed an effect on the soluble fraction (""a"") of DMG starch, decreasing it by respectively 45.3% and 45.4% compared to the CON and MON groups. No effect of PAP was observed for any in situ degradability parameters of starch from HMMS or pectin of CiPu. It was concluded that the polyclonal antibody preparation had limited effect on the in situ degradability of the tested energy sources.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

An in vivo study was conducted to verify the ability of laser fluorescence (LF) to assess the activity status of occlusal caries in primary teeth, using different air-drying times. Occlusal sites (707) were examined using LF (DIAGNOdent) after air-drying for 3 s and 15 s, and the difference between readings (DIF15 s-3 s) was calculated. For concurrent validation of LF, visual criteria-Nyvad (NY) and Lesion Activity Assessment associated with the International Caries Detection and Assessment System (LAA-ICDAS)-were the reference standards for lesion activity. Histological exam using a pH-indicator dye (0.1% methyl red) was performed in 46 exfoliated/extracted teeth for criterion validation. LF readings and DIF15 s-3 s were compared using Kruskall-Wallis and Mann-Whitney tests. Receiver operating characteristic analyses were performed and validity parameters calculated, considering the caries activity assessment. Using NY, active lesions (3 s: 30.0 +/- 29.3; 15 s: 34.2 +/- 30.6) presented higher LF readings than inactive lesions (3 s: 17.0 +/- 16.3; 15 s: 19.2 +/- 17.3; p <0.05), different from LAA-ICDAS. Active cavitated caries resulted in higher LF readings (3 s: 50.3 +/- 3.5; 15 s: 54.7 +/- 30.2) than inactive cavitated caries (3 s: 19.9 +/- 16.3; 15 s: 22.8 +/- 16.8). Therefore, LF can distinguish cavitated active and inactive lesions classified by NY, but not by LAA-ICDAS; however, this difference might be related to the visual system rather than to LF. The air-drying time could be an alternative to improve the caries activity assessment; however, longer air-drying time is suggested to be tested subsequently. (C) 2010 Society of Photo-Optical Instrumentation Engineers. [DOI: 10.1117/1.3463007]

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Background A higher burden of head and neck cancer has been reported to affect deprived populations. This study assessed the association between socioeconomic status and head and neck cancer, aiming to explore how this association is related to differences of tobacco and alcohol consumption across socioeconomic strata. Methods We conducted a case-control study in Sao Paulo, Brazil (1998-2006), including 1017 incident cases of oral, pharyngeal and laryngeal cancer, and 951 sex- and age-matched controls. Education and occupation were distal determinants in the hierarchical approach; cumulative exposure to tobacco and alcohol were proximal risk factors. Outcomes of the hierarchical model were compared with fully adjusted ORs. Results Individuals with lower education (OR 2.27; 95% CI 1.61 to 3.19) and those performing manual labour (OR 1.55; 95% CI 1.26 to 1.92) had a higher risk of disease. However, 54% of the association with lower education and 45% of the association with manual labour were explained by proximal lifestyle exposures, and socioeconomic status remained significantly associated with disease when adjusted for smoking and alcohol consumption. Conclusions Socioeconomic differences in head and neck cancer are partially attributable to the distribution of tobacco smoking and alcohol consumption across socioeconomic strata. Additional mediating factors may explain the remaining variation of socioeconomic status on head and neck cancer.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Context. Observations in the cosmological domain are heavily dependent on the validity of the cosmic distance-duality (DD) relation, eta = D(L)(z)(1+ z)(2)/D(A)(z) = 1, an exact result required by the Etherington reciprocity theorem where D(L)(z) and D(A)(z) are, respectively, the luminosity and angular diameter distances. In the limit of very small redshifts D(A)(z) = D(L)(z) and this ratio is trivially satisfied. Measurements of Sunyaev-Zeldovich effect (SZE) and X-rays combined with the DD relation have been used to determine D(A)(z) from galaxy clusters. This combination offers the possibility of testing the validity of the DD relation, as well as determining which physical processes occur in galaxy clusters via their shapes. Aims. We use WMAP (7 years) results by fixing the conventional Lambda CDM model to verify the consistence between the validity of DD relation and different assumptions about galaxy cluster geometries usually adopted in the literature. Methods. We assume that. is a function of the redshift parametrized by two different relations: eta(z) = 1+eta(0)z, and eta(z) = 1+eta(0)z/(1+z), where eta(0) is a constant parameter quantifying the possible departure from the strict validity of the DD relation. In order to determine the probability density function (PDF) of eta(0), we consider the angular diameter distances from galaxy clusters recently studied by two different groups by assuming elliptical (isothermal) and spherical (non-isothermal) beta models. The strict validity of the DD relation will occur only if the maximum value of eta(0) PDF is centered on eta(0) = 0. Results. It was found that the elliptical beta model is in good agreement with the data, showing no violation of the DD relation (PDF peaked close to eta(0) = 0 at 1 sigma), while the spherical (non-isothermal) one is only marginally compatible at 3 sigma. Conclusions. The present results derived by combining the SZE and X-ray surface brightness data from galaxy clusters with the latest WMAP results (7-years) favors the elliptical geometry for galaxy clusters. It is remarkable that a local property like the geometry of galaxy clusters might be constrained by a global argument provided by the cosmic DD relation.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In this Letter, we propose a new and model-independent cosmological test for the distance-duality (DD) relation, eta = D(L)(z)(1 + z)(-2)/D(A)(z) = 1, where D(L) and D(A) are, respectively, the luminosity and angular diameter distances. For D(L) we consider two sub-samples of Type Ia supernovae (SNe Ia) taken from Constitution data whereas D(A) distances are provided by two samples of galaxy clusters compiled by De Filippis et al. and Bonamente et al. by combining Sunyaev-Zeldovich effect and X-ray surface brightness. The SNe Ia redshifts of each sub-sample were carefully chosen to coincide with the ones of the associated galaxy cluster sample (Delta z < 0.005), thereby allowing a direct test of the DD relation. Since for very low redshifts, D(A)(z) approximate to D(L)(z), we have tested the DD relation by assuming that. is a function of the redshift parameterized by two different expressions: eta(z) = 1 + eta(0)z and eta(z) = 1 +eta(0)z/(1 + z), where eta(0) is a constant parameter quantifying a possible departure from the strict validity of the reciprocity relation (eta(0) = 0). In the best scenario (linear parameterization), we obtain eta(0) = -0.28(-0.44)(+0.44) (2 sigma, statistical + systematic errors) for the De Filippis et al. sample (elliptical geometry), a result only marginally compatible with the DD relation. However, for the Bonamente et al. sample (spherical geometry) the constraint is eta(0) = -0.42(-0.34)(+0.34) (3 sigma, statistical + systematic errors), which is clearly incompatible with the duality-distance relation.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The kinematic approach to cosmological tests provides direct evidence to the present accelerating stage of the Universe that does not depend on the validity of general relativity, as well as on the matter-energy content of the Universe. In this context, we consider here a linear two-parameter expansion for the decelerating parameter, q(z)=q(0)+q(1)z, where q(0) and q(1) are arbitrary constants to be constrained by the union supernovae data. By assuming a flat Universe we find that the best fit to the pair of free parameters is (q(0),q(1))=(-0.73,1.5) whereas the transition redshift is z(t)=0.49(-0.07)(+0.14)(1 sigma) +0.54-0.12(2 sigma). This kinematic result is in agreement with some independent analyses and more easily accommodates many dynamical flat models (like Lambda CDM).