972 research outputs found
Wave propagation over a beach within a nonlinear theory
Wave propagation over a beach is considered within a nonlinear theory in shallow water. Lagrangian coordinates are used to describe the problem. The solution is expanded in double series involving a small parameter and local oscillations. Two cases are treated: The beach with appreciable inclination on the horizontal (cliff) and the beach of small inclination. We show that finite solutions are obtained, in contrast to the linear theory which involves a logarithmic singularity at the shoreline. For the cliff, it is shown that local oscillations do not appear in the first two orders of approximation, and the incident wave is totally reflected without loss of energy at this order of approximation. The case of an incident wave on the beach is considered. The deformation of this wave is investigated and explicit formulae are obtained for the reflected wave and for the local oscillations, to shed light on the energy transfer due to interaction with the beach
Aspergilli and their aflatoxins contamination of poultry and animal feedstuff samples in western region of Saudi Arabia
Aspergillus and their aflatoxins contaminations were studied in sixty poultry and animal feedstuff samples collected from the western region (Jeddah, Makkah and Taif cities) from Saudi Arabia. Fourteen species of Aspergillus were isolated and identified in the present investigation using Potato Dextrose Agar (PDA) at 27ÂşC. The identification of isolated Aspergillus was confirmed by using internal transcribed spacer (ITS) region sequencing for representative species (194 species) of the collected Aspergillus sp. were sequenced and the obtained sequence results were deposited in Gene Bank under accession numbers. The sequence results indicated to the full correspondence between the molecular identification of the isolated fungi and the morphological identification. Moisture content was considered indicator for the number of Aspergillus isolated, therefore, Aspergillus and their aflatoxins were isolated in high counts from Jeddah and Taif according to the moisture content. Therefore, A. flavus was the most common species (59.78%), followed by A. niger (21.59%). The co-occurrence of Aspergillus species ranged from one species to 6 species per sample. The frequencies of occurrence for most afltoxigenic species isolated from studied samples ranged from 2 to 56%. Aspergillus flavus contaminated the majority of investigated feedstuff samples and the co-occurrence of more than one aflatoxigenic species was reported in many samples
Analytical Study on Building a Comprehensive Big Data Management Maturity Framework
Harnessing big data in organizations today realizes benefits for competitive advantage. Generated profound insights are reflected in informed decision making, creating better business plans, and improved service delivery. Yet, organizations are still not recognizing how mature their big data management capabilities are. However, there is no structured approach to assess and build necessary capabilities for valuable big data utilizing, which draws a clear improvement pathway. Existing solutions lack a consistent perception of big data management capabilities, a reliable assessment, and a rigid improvement scheme. This paper contributes in building an analytical study on existing key works in assessing and building big data management capabilities. Drawing upon the results and gaps revealed from this analytical study, the main requirements for building a comprehensive big data management maturity framework are defined. This framework will enable organizations to assess and improve their current capabilities towards effective big data management.https://dorl.net/dor/ 20.1001.1.20088302.2022.20.1.13.
Reflection and Transmission of an Incident Progressive Wave by Obstacles in Homogeneous Shallow Water
The influence of a suspended fixed obstacle on an incident progressive wave inside an ideal homogeneous shallow water is studied in two dimensions. The fluid occupies an infinite channel of a constant depth, and a fixed obstacle of a small horizontal extent is partially submerged without contact with the bottom of the channel. An asymptotic double series expansion for the solution is used. The procedure enables us to calculate analytic expressions for the local perturbations up to the second order. The results of the first-order approximation indicate that no reflections exist. The second-order approximation of the solution is found to be the superposition of a progressive wave and local perturbations. For approximations of order higher than two, a secular term which increases monotonically with time and distance appears in the expressions for the progressive wave. This unacceptable result is due to a certain aspects in the mathematical procedure used. For this reason, the procedure is modified by using a suitable transformation of variables which reduces the determination of the transmitted wave to the solution of the KdV equation. As an illustration, the special case of the incident uniform flow is considered and the stream lines of the resulting flow are drawn
Effect of Shape, Orientation and Aging of a Plastic Greenhouse Cover on the Degradation Rate of the Optical Properties in Arid Climates
In arid climates, the optical properties of plastic-covered greenhouses deteriorate very quickly. To examine the effect of greenhouse shape and orientation on the degradation rate of cover
optical properties, four greenhouse prototypes were constructed in two shapes (duo-pitched roof and tunnel), covered with a 200  m thick low-density polyethylene film. Two types were oriented in the North–South direction, the other two in the East–West direction, and all were exposed for one year to an arid climate. Samples were taken from the different surfaces of each cover for testing. The total transmittance (Ts) and reflectance (Rs) of the samples were measured and averaged to obtain the whole cover properties (T and R). Measurements were carried out periodically every 30 days for the four prototypes. The degradation behavior of the optical properties of each cover surface (Ts, Rs) and the whole cover (T, R) was investigated for the four film covers during the exposure time. Results show that the degradation rate of Ts depends on the surface location and the cover orientation. Among the different surfaces of the four prototype covers, the maximum difference in the Ts value between the E and N surfaces for the tunnel cover oriented in the N–S direction was 15.5%. Although the variation of the Ts value among the different cover surfaces was found, the time dependences of the whole cover transmittance (T) for the four covers tested were almost similar. Accordingly, the shape and orientation of the small size greenhouses did not significantly affect the degradation rate of the cover optical properties. In the four covers tested, the reduction in the global solar radiation transmittance (T) was 27–31% after one-year exposure compared to the new film. Nonlinear correlation was developed to predict the degradation rate of the cover transmittance as a
function of the accumulated solar irradiance
Metallothionein induction reduces caspase-3 activity and TNFα levels with preservation of cognitive function and intact hippocampal neurons in carmustine-treated rats
Hippocampal integrity is essential for cognitive functions. On the other hand, induction of metallothionein (MT) by ZnSO4 and its role in neuroprotection has been documented. The present study aimed to explore the effect of MT induction on carmustine (BCNU)-induced hippocampal cognitive dysfunction in rats. A total of 60 male Wistar albino rats were randomly divided into four groups (15/group): The control group injected with single doses of normal saline (i.c.v) followed 24 h later by BCNU solvent (i.v). The second group administered ZnSO4 (0.1 µmol/10 µl normal saline, i.c.v, once) then BCNU solvent (i.v) after 24 h. Third group received BCNU (20 mg/kg, i.v, once) 24 h after injection with normal saline (i.c.v). Fourth group received a single dose of ZnSO4 (0.1 µmol/10 µl normal saline, i.c.v) then BCNU (20 mg/kg, i.v, once) after 24 h. The obtained data revealed that BCNU administration resulted in deterioration of learning and short-term memory (STM), as measured by using radial arm water maze, accompanied with decreased hippocampal glutathione reductase (GR) activity and reduced glutathione (GSH) content. Also, BCNU administration increased serum tumor necrosis factor-alpha (TNFα), hippocampal MT and malondialdehyde (MDA) contents as well as caspase-3 activity in addition to histological alterations. ZnSO4 pretreatment counteracted BCNU-induced inhibition of GR and depletion of GSH and resulted in significant reduction in the levels of MDA and TNFα as well as the activity of caspase-3. The histological features were improved in hippocampus of rats treated with ZnSO4 + BCNU compared to only BCNU-treated animals. In conclusion, MT induction halts BCNU-induced hippocampal toxicity as it prevented GR inhibition and GSH depletion and counteracted the increased levels of TNFα, MDA and caspase-3 activity with subsequent preservation of cognition
Role of polar nanoregions with weak random fields in Pb-based perovskite ferroelectrics
In relaxor ferroelectrics, the role of randomly orientated polar nanoregions (PNRs) with weak random fields (RFs) is one of the most puzzling issues of materials science. The relaxation time of polarization fluctuations of PNRs, which manifests themselves as a central peak (CP) in inelastic light scattering, is the important physical quantity to understand the dynamics of PNRs. Here, the angular and temperature dependences of depolarized and polarized CPs in 0.44Pb(Mg1/3Nb2/3)O3-0.56PbTiO3 single crystals with weak RFs have been studied by Raman and Brillouin scattering, respectively. The CPs observed in Raman scattering show the very clear angular dependence which is consistent with the local tetragonal symmetry. It is different from the well-known local rhombohedral symmetry with strong RFs for Pb(Mg1/3Nb2/3)O3. In Brillouin scattering, depolarized and polarized CPs show two relaxation processes corresponding to transverse and longitudinal fluctuations of PNRs. The remarkable slowing down towards the Curie temperature was observed for transverse fluctuations in local tetragonal symmetry
Super Unification of Physics and Mathematics
This short letter proposes to convert physics and mathematics not to classical mathematical physics but to a far more radically different entity. We call this new logical product "wild topology" which is also known as a general kind of topology ramifying into a Cantor set. Thus the work goes far more beyond our older P-Adicunification of physics and mathematics.
In the course of this process, we enhance both understanding as well as computation of not only classical physics but more importantly also quantum physics and cosmology. In particular, we free quantum mechanics from several of the paradoxes and counter intuitive features which has historically plagued it since its very inception
Breakdown of Energy Equipartition in a 2D Binary Vibrated Granular Gas
We report experiments on the equipartition of kinetic energy between grains
made of two different materials in a mixture of grains vibrated in 2
dimensions. In general, the two types of grains do not attain the same granular
temperature, Tg = 1/2m v^2. However, the ratio of the two temperatures is
constant in the bulk of the system and independent of the vibration velocity.
The ratio depends strongly on the ratio of mass densities of the grains, but is
not sensitive to the inelasticity of grains. Also, this ratio is insensitive to
compositional variables of the mixture such as the number fraction of each
component and the total number density. We conclude that a single granular
temperature, as traditionally defined, does not characterize a multi-component
mixture.Comment: 4 pages, 5 figures, submitted to Physical Review Letters, updated
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