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Search Results: 1 - 10 of 601726 matches for " R.A.; "
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A solubilidade de fosfatos naturais em solu??o de ácido cítrico a 2%, na propor??o de 1:200
Catani, R.A.;
Anais da Escola Superior de Agricultura Luiz de Queiroz , 1970, DOI: 10.1590/S0071-12761970000100001
Abstract: the solubility of three samples of pure tricalcium phosphate and of one sample of bone meal in 2% citric acid solution, in the proportion of 1:200, is almost total, that is,their content in p2o5. by other side, the rock phosphates present a partial solubility in 200 ml of 2% citric acid. the number of milliequivalents of hydrogen in 200 ml of 2% citric acid solution is almost the doble of the number required for the solubilization of 1 gram of phosphate or calcium fluophosphate. on the basis of the data obtained from this study it is possible to stablish the proportion of 1:200 for the extraction of p2o5 of rock phosphate and to interpret the extracted p2o5 as equivalent to tricalcium phosphate (tfe).
Transient outward potassium current and Ca2+ homeostasis in the heart: beyond the action potential
Bassani, R.A.;
Brazilian Journal of Medical and Biological Research , 2006, DOI: 10.1590/S0100-879X2006000300010
Abstract: normal central nervous system development relies on accurate intrinsic cellular programs as well as on extrinsic informative cues provided by extracellular molecules. migration of neuronal progenitors from defined proliferative zones to their final location is a key event during embryonic and postnatal development. extracellular matrix components play important roles in these processes, and interactions between neurons and extracellular matrix are fundamental for the normal development of the central nervous system. guidance cues are provided by extracellular factors that orient neuronal migration. during cerebellar development, the extracellular matrix molecules laminin and fibronectin give support to neuronal precursor migration, while other molecules such as reelin, tenascin, and netrin orient their migration. reelin and tenascin are extracellular matrix components that attract or repel neuronal precursors and axons during development through interaction with membrane receptors, and netrin associates with laminin and heparan sulfate proteoglycans, and binds to the extracellular matrix receptor integrins present on the neuronal surface. altogether, the dynamic changes in the composition and distribution of extracellular matrix components provide external cues that direct neurons leaving their birthplaces to reach their correct final location. understanding the molecular mechanisms that orient neurons to reach precisely their final location during development is fundamental to understand how neuronal misplacement leads to neurological diseases and eventually to find ways to treat them.
The extracellular matrix in multiple sclerosis: an update
Sobel, R.A.;
Brazilian Journal of Medical and Biological Research , 2001, DOI: 10.1590/S0100-879X2001000500007
Abstract: extracellular matrix (ecm) molecules play important roles in the pathobiology of the major human central nervous system (cns) inflammatory/demyelinating disease multiple sclerosis (ms). this mini-review highlights some recent work on cns endothelial cell interactions with vascular basement membrane ecm as part of the cellular immune response, and roles for white matter ecm molecules in demyelination and remyelination in ms lesions. recent basic and clinical investigations of ms emphasize axonal injury, not only in chronic ms plaques, but also in acute lesions; progressive axonal degeneration in normal-appearing white matter also may contribute to brain and spinal cord atrophy in ms patients. remodeling of the interstitial white matter ecm molecules that affect axon regeneration, however, is incompletely characterized. our ongoing immunohistochemical studies demonstrate enhanced ecm versican, a neurite and axon growth-inhibiting white matter ecm proteoglycan, and dermatan sulfate proteoglycans at the edges of inflammatory ms lesions. this suggests that enhanced proteoglycan deposition in the ecm and axonal growth inhibition may occur early and are involved in expansion of active lesions. decreased ecm proteoglycans and their phagocytosis by macrophages along with myelin in plaque centers imply that there is "injury" to the ecm itself. these results indicate that white matter ecm proteoglycan alterations are integral to ms pathology at all disease stages and that they contribute to a cns ecm that is inhospitable to axon regrowth/regeneration.
Interferon gamma is a key cytokine in lung phase immunity to schistosomes but what is its precise role?
Wilson, R.A.;
Brazilian Journal of Medical and Biological Research , 1998, DOI: 10.1590/S0100-879X1998000100022
Abstract: vaccination of mice with radiation-attenuated cercariae of schistosoma mansoni induces a high level of protection against challenge with normal larvae. the immune effector mechanism, which operates in the lungs, is a cell-mediated delayed-type hypersensitivity response and involves the formation of a tight focus of mononuclear cells around embolised larvae. cd4+ t cells with th1 characteristics are a major component of the infiltrate. they secrete abundant interferon gamma (ifng) upon antigen stimulation in vitro, whilst in vivo neutralisation of the cytokine results in 90% abrogation of immunity. ifng can induce a large number of genes and an attempt has been made to identify the ones which are essential components of the effector mechanism. inducible nitric oxide synthase (inos) is such a candidate and nitric oxide (no) is produced by cultures of airway leucocytes from the lungs of vaccinated mice post-challenge. however, the continued resistance of mice with a disrupted inos gene indicates that no has only a minor role in the protective response. mice with a disrupted ifng receptor gene have been used to dissect the role of the cytokine. after vaccination and challenge, cd4+ t cells from the pulmonary interstitium have reduced levels of icam-1 and lfa-1 expression, compared to wild-type animals, which coincides with a reduced cohesiveness of foci. however, immunity is not significantly impaired in mice with a disrupted icam-1 gene, and focus formation is normal. similarly, a role has not been found for cd2/cd48 interactions in cell aggregation. possible ifng-inducible molecules yet to be fully investigated include other ligand-receptor pairs, chemokines, and tumour necrosis factor a.
Definición y cálculo de tensores mediante el paquete GRTensor
Sussman, R.A.;
Revista mexicana de física , 2007,
Abstract: the package grtensor allows one to define, calculate and manipulate tensors of arbitrary range and dimension from the components of a metric, either in a coordinate basis or tetrad. by considering simple and instructive examples we implement basic applications of this package to define and compute tensorial objects of common usage in general relativity.
Customer Relationship Management and Hospital Service Quality in Nigeria
R.A Gbadeyan
African Research Review , 2010,
Abstract: Health care delivery has become one of the fundamental issues being given attention by governments of most developing countries. The Objective of this study therefore is to examine how Customer Relationship Management can be employed to bring about improve health service quality in Nigeria. The data for the study was collected through questionnaire instrument administered to 200 health workers at the University of Ilorin Teaching Hospital Ilorin, Nigeria. Thus the study adopted a case study approach method. Exploratory test was conducted to determine the mean age of the Sample distribution, while Chi-square, Kolmogorov Smirnov test and Factor Analysis were Statistical techniques employed to further perform data analysis on the study. Findings reveal that the mean age was not significantly different from the hypothesized value, Customer Relationship Management (C.R.M.) has significant effects on the quality of Hospital Services in Nigeria ( χ2 =0.000, d.f=2 and P ≤ 0.05) and three factors namely: Interactive Management, Personalisation, and Relations with Patients are relevant factors in the implementation of Customer Relationship Management in Nigerian Hospitals. The study recommends pre- planning and understanding expectation of Stakeholders for CRM successful implementation. Key Words: Customer Relationship Management, Hospital Services, Patient’s Satisfaction, Isolation Ward and Interactive Management
Perspectives on Urban Renewal and Transportation Development in Lagos: Implications for Urban Development in Nigeria
R.A Olawepo
African Research Review , 2010,
Abstract: Lagos city has emerged a growing Primate city, at least, growing faster than any other city in sub-Sahara Africa in terms of population, urban renewal, roads and infrastructural development. The problems of urban development and transportation in Lagos can be summarized into the following: the problem of old narrow streets in most of the unplanned areas of the city and the emerging incursion of transport infrastructural facilities into the residential areas as a result of growing traffic volumes on Lagos roads. Similarly, the problems of haphazard development and slum expansion due to increased population pressure have necessitated the state Government to initiate massive renewal programmes. These are implemented through Public Private Partnership Initiatives. This has given rise to the building of the Atlantic City’ and the Bus Rapid Transit. What happens in Lagos if extended to other states is being envisaged to be the panacea to urban development in Nigeria.
De-Marketing of Harmful Products in Nigeria
R.A. Gbadeyan
Pakistan Journal of Social Sciences , 2012, DOI: 10.3923/pjssci.2010.449.455
Abstract: Harmful products are sometime being marketed to the consumers by manufacturers and their distributors most especially the wholesalers and the retailers. The consequences of this phenomenon has made it imperative for government and private sector to employ de-marketing strategy to address this situation. The objective of this study therefore is to examine the major problems facing these de-marketing strategies being employed by both the government and private sector and proffer the needed solutions to these problems. In other word, the objective of this study is to examine how de-marketing tools have been effectively used against consumption of harmful products in Nigeria. The t-test and Chi-square were the statistical techniques employed to test the hypotheses raised in the study. The results of the findings indicated that the de-marketing strategy has been effective while inadequate legislation serve as one of the major problems facing this policy. The study recommends that a stiffer penalty in form of capital punishment or life imprisonment should be imposed on offenders who are involved in production and sales of harmful products so as to serve as deterrent to others.
Psychodemographic Predictors of School Attendance Behaviour among Secondary School Students in Osun State, Nigeria
R.A. Animasahun
The Social Sciences , 2013,
Abstract: The study investigated the possible Psycho-demographic variables (Gender, Age, Family type, Spiritual intelligence, Emotional intelligence, Creativity, Self efficacy, Motivation and Goal setting) as predictors of School Attendance Behaviour among secondary school students in Osun State, Nigeria. Multistage stratified sampling methods were used in selecting 626 students with age range between 10 and 21 years from JS1-SS3. They responded to ten valid and reliable instruments, namely: School Attendance Behaviour Rating Scale, Students ’Academic Achievement Motivation, Goal Setting Scale, Emotional Intelligence Scale, Creativity Scale, Generalized Self Efficacy Scale and Spiritual Intelligence Questionnaire. Data analysis involved the use of Multiple Regression Analysis to seek for possible predictive capacity of the nine independent variables on School Attendance Behavior. The results indicated positive correlations among variables and the nine independent variables when, taken together, contributed 64.6%, while relative contributions revealed Motivation as the highest contributor with a β of 0.541, followed by Goal setting (B = 0.248), Emotional Intelligence (B = 0.235), Creativity (B = 0.189), Age (B = 0.080), Self efficacy (B = 0.042), Family Type (B = 0.041), Spiritual Intelligence (B = 0.023) and Gender (B = 0.006), respectfully. On the basis of this finding, recommendations were made that parents must constantly motivate their children to go to school, while Guidance Counsellors need to organize group counselling programmes to teach students on benefits of Western education, Goal setting skills, Emotional intelligence, Creativity, Self efficacy and Spiritual intelligence to reduce truancy to the bearest minimum and encourage school attendance behaviour.
Principals Personal Variables as Determinants ofAdministrative Effectiveness and Efficiency
R.A. Adenuga
Pakistan Journal of Social Sciences , 2012,
Abstract: This study investigated Principal Personal Variables as determinant of administrative effectiveness and efficiency using descriptive design of correlation type. Three hundred principals selected through simple random sampling technique from secondary schools in Ogun State participated in this study. The researcher developed and validated questionnaires tagged Leaders Personal Variable Questionnaire (LPVQ) and Personal Effectiveness Scale (PES) for data collection. The Multiple Regression and Analysis of Variance (ANOVA) were the major tools used for data analysis. Findings from the study revealed that a low, positive correlation (R = 0.20) exists between the four predictor variables (age, sex, experience, qualification) and principal personal effectiveness. It was recommended among others that principals and head of schools should be subjected to regular training and workshops boost their effectiveness and efficiency. The principals personal variables of experience and qualification should be one of the factors in appointing teachers to position of authorities in schools.
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