1,313 research outputs found
Electron Inertial Effects on Rapid Energy Redistribution at Magnetic X-points
The evolution of non-potential perturbations to a current-free magnetic
X-point configuration is studied, taking into account electron inertial effects
as well as resistivity. Electron inertia is shown to have a negligible effect
on the evolution of the system whenever the collisionless skin depth is less
than the resistive scale length. Non-potential magnetic field energy in this
resistive MHD limit initially reaches equipartition with flow energy, in
accordance with ideal MHD, and is then dissipated extremely rapidly, on an
Alfvenic timescale that is essentially independent of Lundquist number. In
agreement with resistive MHD results obtained by previous authors, the magnetic
field energy and kinetic energy are then observed to decay on a longer
timescale and exhibit oscillatory behavior, reflecting the existence of
discrete normal modes with finite real frequency. When the collisionless skin
depth exceeds the resistive scale length, the system again evolves initially
according to ideal MHD. At the end of this ideal phase, the field energy decays
typically on an Alfvenic timescale, while the kinetic energy (which is equally
partitioned between ions and electrons in this case) is dissipated on the
electron collision timescale. The oscillatory decay in the energy observed in
the resistive case is absent, but short wavelength structures appear in the
field and velocity profiles, suggesting the possibility of particle
acceleration in oppositely-directed current channels. The model provides a
possible framework for interpreting observations of energy release and particle
acceleration on timescales down to less than a second in the impulsive phase of
solar flares.Comment: 30 pages, 8 figure
The efficacy of the CABRI 3D program in increasing academic achievement in mathematics of middle students in Arar City
The present research aimed to investigate the efficacy of the CABRI 3D Program in increasing the academic achievement in mathematics of middle school students in Arar city, Northern Border Region. Through its general objective, the study sought to answer the following key question: Are there statistical differences in the academic achievement in mathematics of the members of the study sample as a result of the implementation of the CABRI 3D Program? Methodology and research methods. The study sample consisted of (70) junior high school students in public schools in Arar city. The sample was distributed randomly between a first control group of (36) students and a second test group of (34) students, who learned using the CABRI 3D Program. After conducting the study, all arithmetic means were extracted, along with the standard deviations of the overall scores of the individuals in the sample, Results, and scientific novelty. The results of the study indicated that the students in the test group on whom the CABRI 3D Program was implemented had better direct and deferred academic achievement than the students in the control group who learned in the traditional way
Application of the mixture design to decolourise effluent textile wastewater using continuous stirred bed reactor
Important pollutants in textile effluents are mainly recalcitrant organics, colours, toxicants and inhibitory compounds, surfactants, chlorinated compounds (AOX), pH and salts. An aerobic system using a continuous stirred bed reactor (SBR) was continuously operated at constant temperature and fed with textile wastewater (pH 7 and total chemical oxygen demand (COD) 1 700 mg/â„“).This report is focused on the decolourisation treatment of effluent by a bacterial consortium (Sphingomonas paucimobilis, Bacillus sp. and filamentous bacteria). The influence of the different mixtures of 3 strains on the decolourisation of effluent (cell density fixed at OD600 = 1) was studied using an equilateral triangle diagram and mixture experimental design to assess colour and COD removal during species evolution. With the aid of analysis software (Minitab 14.0), the formulation of pure culture was optimised for several responses and the best formulation obtained. The results suggested that the highest predictable specific decolourisation rate and chemical oxygen demand (COD) were 86.72% and 75.06%, respectively. Regression coefficients between the variables and the responses of decolourisation and COD removal were, respectively, R2 = 72.48% and 54.28%, which indicated excellent evaluation of experimental data by the polynomial regression model. UV-visible analysis confirmed biodegradation of effluent.Keywords: textile wastewater, bacterial decolourisation, response surface, mixture design, SB
Circulating intercellular adhesion molecules in blood and bronchoalveolar lavage in Behçet's disease
The aim of this study was to evaluate circulating intercellular adhesion molecule-1 (cICAM-1) in serum and in bronchoalveolar lavage (BAL), as a marker for the inflammatory process in patients with active Behçet's disease (BD). Circulating ICAM-1 was tested by an enzyme linked immuno-sorbent assay in serum and in BAL of patients with BD. These values were compared to those of patients with tuberculosis and to healthy controls. Increased levels of circulating ICAM-1 were found in serum from patients with active BD compared to healthy controls (p < 0.01). Similar levels of serum cICAM-1 were found in BD and tuberculosis. Additionally, both BD and tuberculosis patients exhibited high levels of cICAM-1 in BAL fluid, suggesting that this increase may be a result of the immune system activation in inflammatory sites. Circulating ICAM-1 seemed to have a good discriminative power in identifying active BD, being elevated in all active stages (p < 0.01) compared to remission BD stage. No differences were found in active BD patients depending upon the clinical manifestations. These results suggest that cICAM-1 may be involved in leucocyte adhesion and migration into the vessel wall of the lung. Circulating forms are derived from molecules expressed on the surface of activated cells, as a result of an inflammatory process
Involvement of SNP marker located on the Calcium binding protein gene in adaptive traits and organoleptic performances of the olive tree
Olive trees importance is mainly due to the economic and health benefits, especially in the Mediterranean basin. Unfortunately, to enhance productivity and quality of olive oil, the study of both molecular and phenotypic characterizations of olive cultivars is crucial. We consider the analysis of 14 Tunisian olive cultivars of known origin sampled from different areas of the country based on SNP marker (CALC) located in calcium binding protein gene. Accordingly, we assessed the potential genotype-phenotypes links between the SNP, on the one hand, and the quantitative and qualitative parameters, on the other. The statistical analysis based on bivariate analysis for the CALC marker suggests that Chemlali varieties with CG genotypes have better capacity to produce fruit, fruit oil, oil content in carotene, cholesterol and linoleic acid than homozygote GG genotypes varieties. These results are confirmed by a multivariate logistic regression.Keywords: Olea europaea L; CALC; calcium binding protein; bivariate analysis; multivariate logistic regression
Effectiveness of an Educational Program on University Collegians’ Perceptions of Healthy Exercise pattern
To find out the effectiveness of an educational program on university students' perceptions of a
healthy exercise pattern. A quasi-experimental study to find out the exercise pattern of Mosul
University students for the period from 9th November 2022 to 2nd January 2023, the sample of (60)
students. The questionnaire consists of two parts: a part that measures social and demographic
information and includes (6) items, and a part that measures healthy lifestyle data with regard to
exercise pattern and includes (10) items. Determine the validity of the content of the questionnaire by
presenting it to experts and using the half-division technique and calculating the Pearson correlation
coefficient to determine the validity. The results of the data showed that all (60) students in the study
sample did not have an adequate level of perception of the healthy physical activity pattern in the
pre-test, while the results of the post-test after implementing the program were high, which shows
that there is an improvement in their perceptions of the healthy physical activity pattern.The study
showed that there was an improvement in perceptions of a healthy lifestyle related to exercise pattern
in the study group compared to those in the control group.The study recommended the need to
develop educational programs, lectures, courses and seminars on the benefits of a healthy exercise
pattern that university students must follow to increase their perceptions that lead to changing their
lifestyle and getting rid of wrong behaviors and habits
The Ljapunov-Schmidt reduction for some critical problems
This is a survey about the application of the Ljapunov-Schmidt reduction for
some critical problems
Inflammatory response in induced sputum mononuclear cells from patients with acute exacerbation of asthma.
Examination of sputum provides a direct method to investigate airway inflammation non-invasively in particular Th1 (IL-2, IFN-gamma) and Th2 (IL-4, IL-10) cytokine production. IL-2, IL-4, IL-10 and IFN-gamma cytokine were studied in induced sputum mononuclear cells of asthmatic patients. Sputum induction was performed on 10 patients and 10 normal controls. Basal and mitogen-stimulated cytokine production was determined in induced sputum T-cell culture. Supernatants were collected and assayed not only with specific ELISA but also with polymerase chain reaction (PCR) techniques. Data showed a significantly higher production of IL-10 by both the ELISA and the RT-PCR techniques in asthmatic patients compared with sputum mononuclear cells from healthy controls. IL-4 production was detected at a low level using the ELISA method in asthmatic patients. The RT-PCR analysis detected a significantly IL-4-mRNA expression in all asthmatic patients, compared with controls. Results of IL-10 and IL-4 mRNA expression were reproducible. We did not find any alteration in the expression of the type 1 derived cytokines (IL-2 and IFN-gamma) in asthmatic patients or in healthy controls. Our study showed a tendency of induced sputum mononuclear cells to express a Th2-like cytokine pattern in acute exacerbation of asthmatic patients, where IL-10 and IL-4 are synthesized in larger amounts. The combination of sputum induction as a non-invasive tool to explore the lung and the identification of disease-associated cytokine expression and of specific cytokine mRNA should help elucidate mechanisms of the immunologically mediated inflammatory responses in asthma
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