8,042 research outputs found

    Dark Matter Annihilation and the PAMELA, FERMI and ATIC Anomalies

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    If dark matter (DM) annihilation accounts for the tantalizing excess of cosmic ray electron/positrons, as reported by the PAMELA, ATIC, HESS and FERMI observatories, then the implied annihilation cross section must be relatively large. This results, in the context of standard cosmological models, in very small relic DM abundances that are incompatible with astrophysical observations. We explore possible resolutions to this apparent conflict in terms of non-standard cosmological scenarios; plausibly allowing for large cross sections, while maintaining relic abundances in accord with current observations.Comment: 13 pages, 3 figures; published for publication in Physical Review

    BEHAVIOR OF REINFORCED CONCRETE CONTINUOUS BEAMS STRENGHENED WITH NEAR SURFACE MOUNTED REINFORCEMENT

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    Using Near Surface Mounted (NSM) technique for flexural strengthening of reinforced concrete continuous beams became particularly attractive for researchers and applicators. Due to the existence of carbon fiber reinforced polymer (CFRP)laminates as external strengthening it is subjected to severe damage resulting from mechanical and environmental conditions. There is limited experimental work investigating the behavior of reinforced concrete continuous beams strengthened using NSM technique.This paper presents an experimental investigation of the behavior of reinforced concrete continuous beams strengthened with near surface mounted (NSM) technique in the hogging and sagging moment region. The main variable was changing the lengths of the NSM strips within the negative and positive moment region. The effect of the change in lengths of the NSM strips on the failure load, mid-span deflection, strain on reinforcement, slippage of CFRP strips and crack widths were investigated. The study revealed that the NSM technique can enhance crack and failure loads and controls crack widths

    Evaluation of the probiotic potential of lactic acid bacteria isolated from faeces of breast-fed infants in Egypt

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    The probiotic-related characteristics of 55 strains of lactic acid bacteria isolated from the faeces of 3 - 6 months old breast-fed infants were determined. The API 50 CH and SDS-PAGE techniques wereemployed to ascertain the identity of the isolated strains. The predominant species among the isolated strains were Lactobacillus (Lb.) acidophilus, Lb. plantarum, Enterococcus (E.) faecium, and E. faecalis. Probiotic properties such as bile resistance, acid tolerance, and adhesion to intestinal mucous were assessed. In vitro results obtained showed that five strains, Lb. plantarum (P1 and P164), Lb. pentosus (P191), and Lb. fermentum (P10, P193) were able to meet the basic requirements for probiotic functions as they demonstrated probiotic characteristics such as tolerance to pH 3, growth in 0.4% oxgall and adhesion to intestinal mucous. The results obtained in this investigation will be used to selectpotentially probiotic strains for in vivo study

    Comparison of Ising magnet on directed versus undirected Erdos-Renyi and scale-free network

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    Scale-free networks are a recently developed approach to model the interactions found in complex natural and man-made systems. Such networks exhibit a power-law distribution of node link (degree) frequencies n(k) in which a small number of highly connected nodes predominate over a much greater number of sparsely connected ones. In contrast, in an Erdos-Renyi network each of N sites is connected to every site with a low probability p (of the orde r of 1/N). Then the number k of neighbors will fluctuate according to a Poisson distribution. One can instead assume that each site selects exactly k neighbors among the other sites. Here we compare in both cases the usual network with the directed network, when site A selects site B as a neighbor, and then B influences A but A does not influence B. As we change from undirected to directed scale-free networks, the spontaneous magnetization vanishes after an equilibration time following an Arrhenius law, while the directed ER networks have a positive Curie temperature.Comment: 10 pages including all figures, for Int. J, Mod. Phys. C 1

    Oxidative stress pattern in hepatitis C patients co-infected with schistosomiasis

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    This study was designed to investigate the role of hepatitis C virus (HCV)-induced oxidative stress in the pathogenesis of the disease with the measurement of tumor necrosis factor (TNF-∝) and super oxide dismutase (SOD). Eighty patients from Hepatology Unit, Faculty of Medicine, Ain Shams University, were investigated. Thirty patients with bilharzial HCV and 30 patients with non-bilharzial HCV as compared to 20 healthy controls of the same age and sex ratio were investigated. The concentrations of liver enzymes [glutamic oxaloacetic transaminase (GOT), glutamic pyruvic transaminase (GPT), alkaline phosphatase (ALP)], bilirubin (Bil), albumin (Alb) and total protein (TP) as well as TNF-α and Mn-SOD were determined. The mean level of the different liver function tests in the three groups in the study showed that the levels of GOT, GPT and ALP were significantly higher in the HCV groups as compared to the control group (p < 0.05). While serum bilirubin, albumin and total protein were non-significantly decreased in the HCV groups as compared to the control group (p > 0.05). Furthermore, the mean level of TNF-α was significantly higher in the HCV groups as compared to the control group (p < 0.001) and SOD was significantly decreased in the HCV groups as compared to the control group (p < 0.001). There is a cause-effect relationship between increased levels of TNF-α and decreased levels of SOD, relative to progression of chronic HCV, especially with bilharzias co-infection. Supporting the view that oxidative damage plays a role in chronic HCV infection, also TNF-α establishes a positive auto regulatory loop that can amplify the inflammatory response and lead to chronic inflammation. More evidence indicates that HCV block apoptosis and prolong survival of the host cell in order to gain time for replication and increase viral progeny production.Key words: Hepatitis C virus, tumor necrosis factor-alpha, superoxide dismutase, oxidative stress, schistosomiasis

    Clinical characteristics of depression among adolescent females: a cross-sectional study

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    <p>Abstract</p> <p>Background</p> <p>Adolescents rarely seek psychiatric help; they even hesitate to disclose their feelings to their parents. However; the adolescents especially the females experience depressive symptoms more frequently than general population. Do they experience classic depressive symptoms? Are there symptoms specific to this subpopulation?</p> <p>Aim of the study</p> <p>Through this study, the authors aimed to estimate the prevalence of depressive disorders in Egyptian adolescent female students. They also expected a characteristic profile of symptoms for the adolescent females. However available literature provides no guidance in the description of this profile of symptoms.</p> <p>Methods</p> <p>A number of 602 adolescent females were interviewed, and subjected to General Health Questionnaire (GHQ); Children Depression Inventory (CDI), Structured Clinical Interview for DSM-IV Axis-I Disorders (SCID-I), then Hamilton Rating Scale for Depression (Ham-D). Results were analyzed by the use of SPSS-15.</p> <p>Results</p> <p>The study revealed the prevalence of depression in the sample of the study to be 15.3% (measured by CDI), and 13.3% (measured by SCID-I). Fatigue was the most common presenting depressive symptom (81.3%), in addition to other emotional, cognitive and physiological symptoms. Suicidal ideations were the most common suicidal symptoms in depressed adolescent females (20%), with 2.5% serious suicidal attempts.</p> <p>Conclusions</p> <p>The somatic symptoms were by far the most common presenting symptom for female adolescents suffering from depressive disorders. Depressive phenomena including unexplained fatigue, decreased energy, psychomotor changes, lack of concentration, weight changes and suicidal ideations may be the presenting complaints instead of the classic sad mood.</p

    Association of dopamine D4 receptor gene variants with autism

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    Background: Autism spectrum disorder (ASD) is a heritable neurodevelopmental disorder with poorly understood and complex etiology. The central dopaminergic system is strongly implicated in ASD pathogenesis. Genes encoding various elements of this system have been linked to ASD. This study aimed to estimate the distribution frequency of dopamine D4 receptor-exon III repeat region polymorphic genotypes among Egyptian children with autism.Methods: This case-control study included 178 children with autism (mean age 4.46±1.72 years) (118 males and 60 females) and a normal control group (n=128) of matching age and gender. Assessments by DSMIV- TR criteria, Stanford-Binet intelligence scale and childhood autism rating scale (CARS) were done. Assay for DRD4 48 bp VNTR genotypes was performed on amplified DNA by RFLP-PCR.Results: The 4/4 allele had the highest frequency among both autistic (39.32%) and control children (62.5%), with no significant difference between them. The 7/7 allele had also a high frequency (33.7%) among autistic patients, which was significantly different (p˂0.05) from the control group (12.5%) Furthermore, 70% of the patients carrying the 7/7 allele had the lowest IQ scores (58.5±6.5).Conclusions: There is a strong evidence that the DRD4 7/7 allele might be a risk factor for autism.

    Seasonal characterization of the nutrients state in Oualidia Lagoon (Moroccan Atlantic coast)

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    The nutrient cycle in Oualidia lagoon, on the Atlantic Moroccan coast, was studied at both spatial and temporal scales, covering spring and summer conditions. Water samples were collected bimonthly at high tide from March to August during years 2011 and 2012 at six stations distributed throughout the lagoon. The physico- chemistry (temperature, salinity, dissolved O2) and nutrient enrichment of the lagoon surface water were monitored. The average nutrient concentration of surface water were 14.4 μmol.l-1 and 28.1 μmol.l-1 for NH4+, 20.4 μmol.l-1 and 19.9 μmol.l-1 for PO43- and 3.7 μmol.l-1 and 7.6 μmol.l-1 for NO2- in 2011 and 2012, respectively. Strong seasonal differences of nutrient distribution at the different stations were noticed. Temperature, salinity and dissolved O2 were correlated with nutrient concentrations, all parameters showing low spatial (inter-station) variability. Hydrological conditions exert a major control on the nutrient cycling in the lagoon. Results of this study are important to increase the richness on the scientific knowledge of nutrient dynamics along the Moroccan Atlantic coast, particularly in the semi-enclosed lagoons that are important transitional systems.Peer reviewe
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