367 research outputs found

    Cold dark matter in brane cosmology scenario

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    We analyze the dark matter problem in the context of brane cosmology. We investigate the impact of the non-conventional brane cosmology on the relic abundance of non-relativistic stable particles in high and low reheating scenarios. We show that in case of high reheating temperature, the brane cosmology may enhance the dark matter relic density by many order of magnitudes and a stringent lower bound on the five dimensional scale is obtained. We also consider low reheating temperature scenarios with chemical equilibrium and non-equilibrium. We emphasize that in non-equilibrium case, the resulting relic density is very small. While with equilibrium, it is increased by a factor of O(10^2) with respect to the standard thermal production. Therefore, dark matter particles with large cross section, which is favored by detection expirements, can be consistent with the recent relic density observational limits.Comment: 14 pages, 1 figur

    Mathematical modelling of Stoneley wave in a transversely isotropic thermoelastic media

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    This paper is concerned with the study of propagation of Stoneley waves at the interface of two dissimilar transversely isotropic thermoelastic solids without energy dissipation and with two temperatures. The secular equation of Stoneley waves is derived in the form of the determinant by using appropriate boundary conditions i.e. the stresses components, the displacement components, and temperature at the boundary surface between the two media are considered to be continuous at all times and positions . The dispersion curves giving the Stoneley wave velocity and Attenuation coefficients with wave number are computed numerically. Numerical simulated results are depicted graphically to show the effect of two temperature and anisotropy on resulting quantities. Copper material has been chosen for the medium and magnesium for the medium Some special cases are also deduced from the present investigation

    Effect of heat and mass transfer and rotation on peristaltic flow through a porous medium with compliant walls

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    Purpose: The purpose of this paper is to investigate the peristaltic flow of an incompressible Newtonian fluid in a channel with compliant walls. The effects of rotation and heat and mass transfer are also taken into account. The governing equations of two dimensional fluid have been simplified under long wavelength and low Reynolds number approximation. An exact solutions is presented for the stream function, temperature, concentration field, velocity and heat transfer coefficient. Design/methodology/approach: The effect of the concentration distribution, heat and mass transfer and rotation on the wave frame are analyzed theoretically and computed numerically. Numerical results are given and illustrated graphically in each case considered. Comparison was made with the results obtained in the presence and absence of rotation and heat and mass transfer. Findings: The results indicate that the effect of the permeability and rotation are very pronounced in the phenomena. Originality/value: The objective of the present analysis is to analyze the effects of rotation, heat and mass transfer and compliant walls on the peristaltic flow of a viscous fluid

    Anti-inflammatory Activity of the Plant Cannabis sativa (L) Petrolium Ether Extract in Albino Rats

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    In this study the plant Cannabis sativa seeds petroleum oil extract was investigated for anti- inflammatory activity on albino rats. The inflammation was firstly obtained by using carrageenan suspension 0.1 ml of 10% saline injected at the sub – plantar region of the left limb for inducing a local acute oedema. A decreased in oedema size was reported after 24 hours for the rats pretreated with carrageenan30 minutes before injection with suspension( 4.56, 0.59 and 0.93 for control, 1ml/kg per day and 0.5ml/kg per day groups given C. sativa seed extracts respectively.), compared to Indomethacin standard antiinflammatory drug which reported a decrease in oedema size diameter to 0.55mm, which indicated an increase inhibition percentages were reported for the different pretreated groups 0.00, 87.03, 79.56 and 87.91 including the comparative Indomethacin treated groups of rats respectively. On the other hand, the post-treated groups of rats (given C. sativa oil extract after 30 minutes of injection of suspension) showed a similar results for maximum concentration 1 ml/day of C. sativa oil extract in comparison to the standard drug. Hence, such results recommend the prospect focus for the preventive medication use of the extract. The study also highlights no significant changes for serum and protein of the blood taken from rats of the experiments. Although there were significant decrease in lymphocyte and neutrophil, but the changes were not significant. Indomethacin was given to the rats used for a comparative drug (10mg/kg). Moreover, the drug indomethacin used as a comparative parameter showed similar results in comparison to the extract, hence wise the reported results may be recommended for use as anti-inflammatory agent and should be explored more to formulate drug on basis of its activity

    Arabic Documents classification method a Step towards Efficient Documents Summarization

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    The massive growth of online information obliged the availability of a thorough research in the domain of automatic text summarization within the Natural Language Processing (NLP) community. To reach this goal, different approaches should be integrated and collaborated. One of these approaches is the classification od documents. Therefore, the aim of this paper is to propose a successful framework for agricultural documents classification as a step forward for a language independent automatic summarization approach. The main target of our serial research is to propose a complete novel framework which not only responses to the question, but also gives the user an opportunity to find additional information that is related to the question. We implemented the proposed method. As a case study, the implemented method is applied on Arabic text in the agriculture field. The implemented approach succeeded in classifying the documents submitted by the user. The approach results have been evaluated using Recall, Precision and F-score measures. DOI: 10.17762/ijritcc2321-8169.15017

    On reflection and transmission of p- and Sv-Waves phenomena at the interface between solid-liquid media with magnetic field and two thermal relaxation times

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    In this research, we studied the reflection and transmission of thermoelastic wave at a solid-liquid interface under influence of two thermal relaxation times and magnetic field. The governing equations are introduced taking into consideration Green-Lindsay theory and Maxwell's stresses. After solving the governing equations, we found the two reflections and transmission coefficients of incident p-(primary) and SV- (Shear Vertical) waves in the presence of thermal relaxation times and a magnetic field. The boundary conditions at the interface have been applied. The appropriate expressions to find the amplitude ratios for the two incidence waves (p- and SV-waves) have been obtained. A numerical calculation is made for the reflection and transmitted coefficients of the incident waves, in which we study the effect of thermal relaxation times and magnetic field. The results obtained are presented graphically for the effect of magnetic field and relaxation times to display the phenomena physical meaning

    Sacrococcygeal teratoma excision: a vertical rather than transverse wound closure

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    Background: The chevron incision has been the standard approach for sacrococcygeal teratoma (SCT) excision. Here, we are reporting our experience of shifting to the vertical posterior sagittal approach.Patients and methods: During the period 2011 through 2016, we operated on 17 (16 female and one male) cases of SCT. Their age at presentation ranged from day 1 to 26 months (mean=4.8 months, median=2 months). The chevron incision was used in five, whereas the vertical posterior sagittal approach was used in 12 patients.Results: In this series, we had one case of perioperative mortality, in addition to another case of perineal wound disruption (in the group of vertical wound closure), which was managed conservatively (to heal by secondary intention) with a very satisfactory hidden scar at 6-month follow-up. Overall, we did not find the vertical approach to add any extra limitations to the surgical exposure or dissection; meanwhile, it provided a well-recognized cosmetic advantage.Conclusion: The vertical posterior sagittal approach for excision of SCT is both feasible and advantageous in terms of the cosmetic outcome. It provides a well-hidden scar in the natal cleft and preserves normal contouring of the buttocks.Keywords: buttock, cosmesis, posterior sagittal, reconstruction, sacrococcygeal teratom

    A study of patient attitudes towards decentralisation of HIV care in an urban clinic in South Africa

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    <p>Abstract</p> <p>Background</p> <p>In South Africa, limited human resources are a major constraint to achieving universal antiretroviral therapy (ART) coverage. Many of the public-sector HIV clinics operating within tertiary facilities, that were the first to provide ART in the country, have reached maximum patient capacity. Decentralization or "down-referral" (wherein ART patients deemed stable on therapy are referred to their closest Primary Health Clinics (PHCs) for treatment follow-up) is being used as a possible alternative of ART delivery care. This cross-sectional qualitative study investigates attitudes towards down-referral of ART delivery care among patients currently receiving care in a centralized tertiary HIV clinic.</p> <p>Methods</p> <p>Ten focus group discussions (FGDs) with 76 participants were conducted in early 2008 amongst ART patients initiated and receiving care for more than 3 months in the tertiary HIV clinic study site. Eligible individuals were invited to participate in FGDs involving 6-9 participants, and lasting approximately 1-2 hours. A trained moderator used a discussion topic guide to investigate the main issues of interest including: advantages and disadvantages of down-referral, potential motivating factors and challenges of down-referral, assistance needs from the transferring clinic as well as from PHCs.</p> <p>Results</p> <p>Advantages include closeness to patients' homes, transport and time savings. However, patients favour a centralized service for the following reasons: less stigma, patients established relationship with the centralized clinic, and availability of ancillary services. Most FGDs felt that for down-referral to occur there needed to be training of nurses in patient-provider communication.</p> <p>Conclusion</p> <p>Despite acknowledging the down-referral advantages of close proximity and lower transport costs, many participants expressed concerns about lack of trained HIV clinical staff, negative patient interactions with nurses, limited confidentiality and stigma. There was consensus that training of nurses and improved health systems at the local clinics were needed if successful down-referral was to take place.</p

    Magnetic resonance imaging of head and neck vascular anomalies: pearls and pitfalls

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    Purpose: The aim of this study was to describe typical MRI features of the head and neck vascular anomalies and the possible diagnostic pitfalls.Patients and methods: Patients with extracranial vascular anomalies of the head and neck, who underwent MRI examinations between January 2013 and January 2016, were included in the study. Precontrast and postcontrast T1-WI,T2-WI, with and without fat saturation were acquired. When indicated, a noncontrast MR angiography was performed. Dynamic postcontrast MRI techniques were available in six children.Results: The study included 33 patients (age ranged from 10 to 20 years, mean: 49 months). MRI confirmed the clinical diagnosis in equivocal cases, and provided proper determination of lesion extension and/or associated intracranial anomalies. The study included 10 cases of vascular tumors (hemangioma), whereas the remaining 23 cases had the diagnosis of vascular malformations (one patient with arteriovenous malformation, one with capillary malformation, seven with venous, nine with macrocystic lymphatic, and five with microcystic lymphatic malformations).Conclusion: Vascular anomalies in the head and neck are mostly diagnosed on clinical basis; however, when the history is uncertain or the diagnosis is equivocal, a well-tailored MR examination can be a single valuable diagnostic tool providing structural and functional information.Keywords: children, head and neck, hemangioma, lymphatic malformation, magnetic resonance angiography, venous malformatio

    Magnetic Field and Gravity Effects on Peristaltic Transport of a Jeffrey Fluid in an Asymmetric Channel

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    In this paper, the peristaltic flow of a Jeffrey fluid in an asymmetric channel has been investigated. Mathematical modeling is carried out by utilizing long wavelength and low Reynolds number assumptions. Closed form expressions for the pressure gradient, pressure rise, stream function, axial velocity, and shear stress on the channel walls have been computed numerically. Effects of the Hartmann number, the ratio of relaxation to retardation times, time-mean flow, the phase angle and the gravity field on the pressure gradient, pressure rise, streamline, axial velocity, and shear stress are discussed in detail and shown graphically. The results indicate that the effect of Hartmann number, ratio of relaxation to retardation times, time-mean flow, phase angle, and gravity field are very pronounced in the peristaltic transport phenomena. Comparison was made with the results obtained in the presence and absence of magnetic field and gravity field
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