5,734 research outputs found
Concurrent -vector fields and energy beta-change
The present paper deals with an \emph{intrinsic} investigation of the notion
of a concurrent -vector field on the pullback bundle of a Finsler manifold
. The effect of the existence of a concurrent -vector field on some
important special Finsler spaces is studied. An intrinsic investigation of a
particular -change, namely the energy -change
($\widetilde{L}^{2}(x,y)=L^{2}(x,y)+ B^{2}(x,y) with \
B:=g(\bar{\zeta},\bar{\eta})\bar{\zeta} \pi\Gamma\widetilde{\Gamma}\beta$-change of the fundamental linear connection in Finsler geometry: the
Cartan connection, the Berwald connection, the Chern connection and the
Hashiguchi connection. Moreover, the change of their curvature tensors is
concluded.
It should be pointed out that the present work is formulated in a prospective
modern coordinate-free form.Comment: 27 pages, LaTex file, Some typographical errors corrected, Some
formulas simpifie
Accelerating Asymptotically Exact MCMC for Computationally Intensive Models via Local Approximations
We construct a new framework for accelerating Markov chain Monte Carlo in
posterior sampling problems where standard methods are limited by the
computational cost of the likelihood, or of numerical models embedded therein.
Our approach introduces local approximations of these models into the
Metropolis-Hastings kernel, borrowing ideas from deterministic approximation
theory, optimization, and experimental design. Previous efforts at integrating
approximate models into inference typically sacrifice either the sampler's
exactness or efficiency; our work seeks to address these limitations by
exploiting useful convergence characteristics of local approximations. We prove
the ergodicity of our approximate Markov chain, showing that it samples
asymptotically from the \emph{exact} posterior distribution of interest. We
describe variations of the algorithm that employ either local polynomial
approximations or local Gaussian process regressors. Our theoretical results
reinforce the key observation underlying this paper: when the likelihood has
some \emph{local} regularity, the number of model evaluations per MCMC step can
be greatly reduced without biasing the Monte Carlo average. Numerical
experiments demonstrate multiple order-of-magnitude reductions in the number of
forward model evaluations used in representative ODE and PDE inference
problems, with both synthetic and real data.Comment: A major update of the theory and example
The Dimensions of Critical Thinking and it’s Relation to Improving the Quality of Life among Female Students at the College of Education, Jouf University
The current study aimed to identify the relationship between the dimensions of critical thinking and quality of life in the light of some variables (academic level, specialization). The study sample consisted of (188) female students at the College of Education, Jouf University, majoring in early childhood and Islamic studies for the academic year 1443 AH / 2021 AD. The descriptive approach, critical thinking scale and quality of life scale have been used to achieve the objectives of the study. The results revealed an average level of critical thinking and quality of life among female students at the College of Education, where the percentages were (68.23%), (71.23%), respectively. There were no statistically significant differences between female students of different academic levels (from the second to the eighth level) on all dimensions of the critical thinking scale and its total score. While there were statistically significant differences between female students majoring in early childhood and Islamic studies in dimensions (interpretation, evaluation of arguments, deduction) and the total score of the critical thinking scale in the direction of early childhood students. However, no statistically significant differences were detected in the other two dimensions (recognition of assumptions, inference). Also, there were no statistically significant differences between students of different academic levels on the dimensions of the quality-of-life scale. There was a statistically significant positive relationship between the dimensions of the critical thinking scale and all dimensions of the quality-of-life scale and its total score. The study recommends conducting more scientific and psychological studies that shed light on the dimensions of critical thinking and the quality of life for university students in line with the Kingdom of Saudi Arabia’s vision of 2030
Synthesis of Some New Thienylazetidinones and Thiazolidinones Containing Pyrazolines
Condensation of thiophene-2-carboxa.ldehyde with 4-aminoacetophenone
gave a quantitative yield of 4-(thienylideneamino)acetophenone(
I). Condensation of I with aromatic aldehydes yielded
the corresponding 4-( 4-substituted-phenyl)-4\u27 -(2-thienyleneamino )chalcone(
II). Interaction of II with hydrazines gave 3-(4-2\u27-thienylideneamino)
phenylpyrazolines (III, IV). Cyclocondensation of
chloroacetyl chloride (or mercaptoa cetic acid) on III or IV gave
3-chloro-1-( 4-pheny lpyrazolin-3\u27 -yl)-4-(2" - thieny l)azetidin -2- ones
(V, VI) and 3-(4-phenylpyrazolin-3\u27-yl)-2-(2"-thienyl)thiazolidin-4-
-ones (VII, VIII), respectivel
Generalized -conformal change and special Finsler spaces
In this paper, we investigate the change of Finslr metrics which we refer to as a
generalized -conformal change. Under this change, we study some special
Finsler spaces, namely, quasi C-reducible, semi C-reducible, C-reducible,
-like, -like and -like Finsler spaces. We also obtain the
transformation of the T-tensor under this change and study some interesting
special cases. We then impose a certain condition on the generalized
-conformal change, which we call the b-condition, and investigate the
geometric consequences of such condition. Finally, we give the conditions under
which a generalized -conformal change is projective and generalize some
known results in the literature.Comment: References added, some modifications are performed, LateX file, 24
page
Knowledge Management Maturity in Universities and its Impact on Performance Excellence "Comparative study"
The paper assesses Knowledge Management Maturity(KMM) in the universities to determine the impact of knowledge management on performance excellence. This study was applied on Al-Azhar University and Al-Quds Open University in Gaza strip, Palestine.
This paper depends on Asian productivity organization model that used to assess KMM. Second dimension which assess performance excellence was developed by the authors. The controlled sample was (610). Several statistical tools were used for data analysis and hypotheses testing, including reliability Correlation using Cronbach’s alpha, “ANOVA”, Simple Linear Regression and Step Wise Regression.
The overall findings of the current study suggest that KMM is suitable for measuring performance excellence. KMM assessment shows that both universities maturity level is in level three. Findings also support the main hypothesis and it is sub- hypotheses. The most important factors effecting performance excellence are: Processes, KM leadership, People, KM Outcomes. Furthermore the current study is unique by the virtue of its nature, scope and way of implied investigation, as it is the first comparative study in the universities of Palestine explores the status of KMM using the Asian productivity Model
Strategic and Operational Planning As Approach for Crises Management Field Study on UNRWA
The research aims to study the role of strategic and operational planning as approach for crises management in UNRWA - Gaza
Strip field- Palestine. Several descriptive analytical methods were used for this purpose and a survey as a tool for data collection.
Community size was (881), and the study sample was stratified random (268).
The overall findings of the current study show that strategic and operational planning is performed in UNRWA. The results of
static analysis show that there are a relation between strategic and operational planning and crises management. In spite this
relation existence, it need more improvement and expanding.
Also there are shortcomings in the way that organization manages the crises before and after they occur. A crisis management is
only practicing during the crisis.
The study suggests that UNRWA must invest in more resources to enhance strategic and operational palming and improve other
methods to face potential crises in the future
KM Maturity Factors Affecting High Performance in Universities
This paper aims to measure Knowledge Management Maturity (KMM) in the universities to determine the impact of knowledge
management on high performance. This study was applied on Al-Quds Open University in Gaza strip, Palestine. Asian
productivity organization model was applied to measure KMM. Second dimension which assess high performance was
developed by the authors. The controlled sample was (306). Several statistical tools were used for data analysis and hypotheses
testing, including reliability Correlation using Cronbach’s alpha, “ANOVA”, Simple Linear Regression and Step Wise
Regression.The overall findings of the current study suggest that KMM is suitable for measuring high performance. KMM
assessment shows that maturity level is in level three. Findings also support the main hypothesis and it is sub- hypotheses. The
most important factors effecting high performance are: Processes, KM leadership, People, KM Outcomes and Learning and
Innovation. Furthermore the current study is unique by the virtue of its nature, scope and way of implied investigation, as it is
the first comparative study in the universities of Palestine explores the status of KMM using the Asian productivity Model
Einstein Geometrization Philosophy and Differential Identities in PAP-Geometry
The importance of Einstein's geometrization philosophy, as an alternative to
the least action principle, in constructing general relativity (GR), is
illuminated. The role of differential identities in this philosophy is
clarified. The use of Bianchi identity to write the field equations of GR is
shown. Another similar identity in the absolute parallelism geometry is given.
A more general differential identity in the parameterized absolute parallelism
geometry is derived. Comparison and interrelationships between the above
mentioned identities and their role in constructing field theories are
discussed.Comment: LaTeX file, 17 pages, comments and criticism are welcom
Thyroid hormone dysfunctions affect the structure of rat thoracic aorta: a histological and morphometric study
Background: There are limited data about the influence of hypothyroidism and hyperthyroidism on the connective tissue component and smooth muscle cells of the thoracic aorta. The aim was to study the histological changes of the wall of the thoracic aorta in the hypothyroid and hyperthyroid rats. Morphometric measurements were also done.Materials and methods: Thirty adult rats were used. They were divided into control, hyperthyroid, and hypothyroid groups. Each group consisted of 10 rats. The animals were sacrificed at the end of 8 weeks and the descending aorta was excised. Sections were stained with haematoxylin and eosin, orcein and Masson’s trichrome stains. Themorphometric measurement included: number of smooth muscle cell nuclei, number of the elastic lamellae, thickness of the tunica media, elastic fibre optic density, and relative collagen area.Results: Atheromatous plagues had been observed in the hyperthyroid group. Thinning and rupture of the elastic lamellae had been observed in the hypothyroid group; these were accompanied with intimal ulceration and aortic dissection. The average number of smooth muscle cell nuclei in the hyperthyroid group had doubled and tripled compared to their fellows in the control and hypothyroid groups, respectively. The thickness of the tunica media increased in the hyperthyroid and hypothyroid groups by 75% and 35%. In addition, the relative collagen area increased in the previously mentioned groups by 142% and 120%, respectively. On the other hand, the mean elastic fibre optic density decreased in both groups by 30%.Conclusions: Structure wall affections of the intima and media of the descending aorta were associated with the thyroid hormone dysfunctions. These changes were more severe in the hypothyroid group.
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