1,721,180 research outputs found
Factors affecting teachers' professional performance in the Sultanate of Oman / Said Salim Hamed Al-Harthy
Get PDFThis research tests a path analytical model of five factors affecting
teacher professional performance in the Sultanate of Oman. Data of 236
teachers from the second cycle of basic education system in Oman were
analyzed using the path analysis approach with AMOS 18.0 software. The
procedures included a) preliminary analysis for the normality and the statistics,
b) path analysis to test the goodness-of-fit, to estimate the effects (direct,
indirect, and total), to build the parsimony model, and to study the moderator
effects of groups. The conceptual framework guiding this study was based on
the theory of performance (Campbell et al., 1993), theory of reasoned action
(Fishbein & Ajzen, 1975), and the history of the theoretical work; related
studies. The instruments of this research were scale of teachers' attitudes
towards teaching and the Omani teachers' professional performance evaluation
instrument.
All research and statistical hypotheses were tested at .05 significant
level. Findings of the fit tests indicated a good fit indices with the overall
sample data (χ2= 3.64, df = 4, p = .457). The path analytical model of factors
affecting teachers professional performance has approved that there are only
two factors affecting, directly, the teachers performance. They are teachers'
work experience (β = .25, p > .05) and the cumulative grade point average (β =
.44, p > .05). Whereas, teachers' attitudes towards teaching, in-service training,
and teachers' self-professional development are, statistically, non-affecting
factors. Also, the path analytical model of factors affecting teachers’
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professional performance has proved that there is only one factor having an
indirect effect on the teachers' performance through the work experience. That
is the in-service training factor by significant value 0.09 of standardized path
coefficient. Findings also show that there are nine total effects among the model
variables. The weakest is the total effect of self-professional development on
teachers professional performance and the strongest is total effects of teachers’
attitudes towards teaching on self-professional development.
Finally, the comparison tests between path models of teachers’ gender
and their specialization reveal significant difference between male and female
models and between applied and human science teachers' models. Therefore,
both gender and specialization of Omanis teachers are considered to be
moderators for the relationships between the studied factors of the fitted path
model
Quality assurance for accreditation of private higher education institutions in the Sultanate of Oman / Said Salim Mohamed Alwahaibi.
Get PDFA study of hepatoprotective effects of Curcuma Xanthorrhiza and Ipomoea Aquatica on thioacetamide-induced liver cirrhosis in rats / Salim Said Salim Alkiyumi
Get PDFIn this work, an attempt was made to study the hepatoprotective effects of ethanol extracts of Curcuma xanthorrhiza and Ipomoea aquatica which are traditionally used for liver complications.
The preliminary work involved an in vitro screening of free radical scavenging of both plants together with silymarin as an agent known to have prevention effect on cirrhosis. In order to study the hepatoprotective and possible mechanism of actions, thioacetamide was used to induce liver cirrhosis in rat model. For each plant extract experiment, 5 groups of rats were assigned as normal control, cirrhotic control, silymarin control, low dose and high dose plant extract. After two months of the experiment, the animals were sacrified and blood and tissues samples were collected for biochemical and histological studies. The parameters included serum liver biomarkers, ALP, AST, ALT, total protein, albumin and bilirubin; liver tissue histological examination; liver tissue Masson’s trichome staining and immunohistochemical staining of α-SMA; liver tissue antioxidant, CAT, SOD; liver tissue lipid peroxidation maker, MDA; serum proinflammatory and profibrotic cytokines TNF-α, TG-Fβ1; liver tissue NF-κB. Then, both plant extracts were subjected to fractionation using column chromatography and the obtained fractions were screened for hepatoprotective in thioacetamide-induced hepatotoxicity normal liver cell line (WRL-68). From each plant extract, the fraction which was most effective in WRL-68 was subjected to LCMS to identify the available compounds. From the LCMS results of the fractions which exhibited best hepatoprotective results, violaxanthin from Ipomoea aquatica and xanthorrhizol from Curcuma xanthorrhiza were selected for further study. The selection of these compounds was based on the available information from the previous studies which
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could be used to infer that these compounds may be the main contributor in the hepatoprotective activity of the fraction and plant extract as whole.
The results demonstrated that ethanol crude extracts of Curcuma xanthorrhiza and Ipomoea aquatica possess hepatoprotective activities in vivo against thioacetamide-induced liver cirrhosis which was proven in biochemical and histopathological findings. In the in vitro screening, Curcuma xanthorrhiza showed higher free radical scavenging than silymarin, however, the free radical scavenging of Ipomoea aquatica was less than silymarin. Nevertheless, both plant extracts significantly increased antioxidant enzymes and reducing lipid peroxidation, which suggest that both plants exhibit hepatoprotective activity, at least in part, by improving endogenous antioxidant status. In addition to that, both extracts exhibited antinflammatory properties to which might have inhibited fibrosis progression through the down regulation of proinflammatory and profibrotic cytokines which lead to the decrease in HSC activation and therefore decreased ECM deposition. This was proven by liver tissue α-SMA and Masson’s trichome staining.
The hepatoprotective activities of both plant crude extracts were confirmed in vitro against thioacetamide induced cell damage in WRL-68. Furthermore, separated fraction 5 from Curcuma xanthorrhiza and fraction 11 from Ipomoea aquatica exhibited the highest hepatoprotective activities against thioacetamide induced cell damage in WRL-68. Similar to the animal study, both crude extracts, their fractions and selected compounds improved antioxidant enzymes and inhibited lipid peroxidation. The selected compounds were more effective than their crude extracts in protecting cell damage and improving antioxidant status. In fact, violaxanthin was more effective than silymarin.
These results suggest that both plant extracts are hepatoprotective and the possible mechanism of action is likely to be through improving endogenous antioxidant status,
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decreasing proinflammatory and profibrotic cytokines, to which xanthorrhizol and violaxanthin may be the main contributors
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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