1,836 research outputs found

    Proton synchrotron radiation of large-scale jets in active galactic nuclei

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    I propose a new mechanism for explanation of nonthernal X-ray emission of large-scale AGN jets. Namely, I assume that this radiation has synchrotron origin emitted by extremely high energy protons, and discuss implications of this model for several prominent hot spots and knots resolved by Chandra in Pictor A, 3C 120, PKS 0637-752, 3C 273.Comment: 17 pages, 8 figures, submitted to MNRA

    Signed degree sets in signed graphs

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    The set D of distinct signed degrees of the vertices in a signed graph G is called its signed degree set. In this paper, we prove that every non-empty set of positive (negative) integers is the signed degree set of some connected signed graph and determine the smallest possible order for such a signed graph. We also prove that every non-empty set of integers is the signed degree set of some connected signed graph

    Depositional Environment of Phosphorites of the Sonrai Basin, Lalitpur District, Uttar Pradesh, India

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    Phosphates are regarded as one of the most important fertilizer minerals used by man. In Sonrai basin of Lalitpur the phosphorites are found to occur as lenticular and detached bodies throughout the Formation of the Bijawar Group. Individual bodies range from a few meters to about 4 km in length, and width varies from thin bands to about 125 meter with P2O5 concentration ranging from 10 to 20%. The Paleoproterozoic Bijawar Group are overlain by the Archaean Bundelkhand Basement Complex and underlain by Vindhyan Supergroup. The occurrence of phosphorites is confined to the Sonrai Formation which consists of massive to brecciated phosphorite within the lower reddish shales, with at least three bands identified. Megascopic study reveals that the brecciated phosphorite is reddish brown in color and fine to medium grained with angular fragments of chert and quartz embedded in a groundmass of iron oxides and secondary silica intercalated with minor veins of chert and iron oxides. The phosphorite horizon in the Lalitpur area is associated with pink to white brecciated massive quartzite, shale, dolomite and limestone of the basal unit. The concentration trends of certain major oxides indicate that the phosphorites are more enriched in CaO, P2O5 and SiO2 than Al2O3, Fe2O3, TiO2, Na2O and K2O. The concentration trends of trace elements reveal that the phosphorites are moderately enriched in Co, Zn, Zr, Pb, U than in Sc, Ba, V, Cr, Ni, , Rb, Sr, Y and Th. The dispersion patter, correlation coefficient and mutual relationship of significant major oxides represented by plotted diagrams, indicate that SiO2, CaO, MgO are antipathetically related with P2O5. The relationship suggests a gradual replacement among these oxides during diagenesis. High values of P2O5 and CaO in the phosphorites indicate more concentration of apatite constituent. The difference in geochemical behavior of CaO and MgO may be due to ionic substitution of Ca+2 by MgO+2 in the apatite crystal lattice during alkaline environment of the basin. The strong negative relationship between P2O5 with Fe2O3 in phosphorites may be due to leaching and/mild weathering of iron from the ores and reprecipitation along with P2O5 in the pore spaces, cavities/voids, veins, etc in highly oxidizing marine environment of the basin. The minimum evidence of organic matter, absence of sulphide minerals and lower concentration of V, Ni, and Cu suggest that the phosphorites were deposited in an oxidizing environment with slightly anaerobic to highly aerobic facies

    Bacteriological profile of wound infections and antimicrobial resistance in selected gram-negative bacteria

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    Background: Managing wound infections is a challenging task. Understanding their resistance pattern is an essential step at reducing its burden in hospital settings. Objective: To determine the bacteriological diversity of wound infections and the antimicrobial resistance exhibited by a selected Gram-negative bacterium in the Aljouf region of Saudi Arabia. Methods: The study retrospectively analysed the antibiograms of wound infections from hospitalized patients for the year 2019. The European Centre for Disease Control guidelines were adopted for the classification of resistant bacteria. Multidrug-, extensive drug-, and carbapenem-resistant isolates are presented as frequencies and percentages. Results: A total of 295 non-duplicate wound swab antibiograms were retrieved, 64.4% (190) and 35.6% (105) isolates were Gram-negative and Gram-positive bacterial infections respectively. Predominant pathogens included Staphylococcus species 21.0% (62), E. coli 16.3% (48) and K. pneumoniae 13.5% (40). 148 (77.9%), 42 (22.1%) and 43 (22.6%) of the Gram-negative isolates were multidrug-, extensively drug- and carbapenem-resistant. The antibiotic resistance exhibited by gram-negative bacteria was 43.4% (234/539), 59.1% (224/379) and 53.7% (101/188) towards carbapenems, 3rd - and 4th – generation cephalosporins. Conclusions: The majority of wound infections are caused by multidrug-, extensively drug- and carbapenem-resistant Gram-negative bacteria. Further studies should focus on the molecular basis of this resistance. Keywords: Wound infections; hospital; Gram-negative bacteria; antibiograms; multidrug-resistance; E. coli

    Growth, fruit set and yield of Santa Rosa plum as affected by nitrogen and boron under rainfed conditions of Kashmir Valley

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    Present experiment was carried out in a seven year old private plum orchard near SKUAST-Kashmir, Shalimar Campus, Srinagar during 2012 and 2013, to examine the response to nitrogenous fertilizer and boron on growth, fruit set and yield of plum var. Santa Rosa. Urea @ 500 g (N1), CaNO3 @ 1450 g (N2), N1 + 50 g boron (N3) and N2 + 50 g boron (N4) were applied at T1 = Full dose in spring, T2 = Full dose after harvest and T3 = 3/4 dose in spring and 1/4 dose after harvest. Observations were recorded on parameters viz. incremental tree girth, shoot extension growth, plant height, plant spread, leaf area, fruit set, fruit drop, yield, yield efficiency. All the growth parameters were high in treatment combination N1T1. Maximum fruit set (19.68 % and 20.90 %) was recorded in N3T2, yield (20.60 kg/tree and 22.88 kg/tree) was recorded in N4T2, yield efficiency (0.45 and 0.46 kg/cm2) was recorded in N4T2 and minimum fruit drop (4.25 % and 4.55 %) were recorded under the treatment combination N4T2 and N4T3, respectively in the both the years. Both sources of nitrogen and boron can be considered as best fertilizer in plum orchards for improving the growth, fruit set, fruit yield, yield efficiency

    Comment on ``Cosmological Gamma Ray Bursts and the Highest Energy Cosmic Rays''

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    In a letter with the above title, published some time ago in PRL, Waxman made the interesting suggestion that cosmological gamma ray bursts (GRBs) are the source of the ultra high energy cosmic rays (UHECR). This has also been proposed independently by Milgrom and Usov and by Vietri. However, recent observations of GRBs and their afterglows and in particular recent data from the Akeno Great Air Shwoer Array (AGASA) on UHECR rule out extragalactic GRBs as the source of UHECR.Comment: Comment on a letter with the above title published by E. Waxman in PRL 75, 386 (1995). Submitted for publication in PRL/Comment

    Studies on drought tolerance in maize inbred lines using morphological and molecular approaches

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    A set of hundred homozygous maize inbred lines were analyzed for drought toleranceby studying twenty-four traits related to maturity, morphological, physiological, yield, quality and few root traits. Evaluation confirmed a wide range of variability revealing significant response of main effects (lines, irrigations and years and their respective digenic and trigenic interactions). These lines were subjected to different stress regimes over years leading to identification of fifteen elite lines which performed well under droughtstress showing inbuilt drought tolerance. A set of 32 SSR markers, having genome-wide coverage, were chosen for genotyping the inbred lines. These markers generated a total of 239 polymorphic alleles with an average of 7.47 alleles per locus. The minimum and maximum PIC value was 0.886 and 0.608 with a mean of 0.782. The coefficient of genetic dissimilarity ranged from 0.215 to 0.148. DARwin derived cluster analysis grouped 15 elite maize lines in three major clusters with five lines each in cluster-III and II and four lines in cluster-I with KDM-361A as root. Molecular diversity however, confirmed diverse genetic nature of six lines (KDM-372, KDM-343A, KDM-331, KDM-961, KDM-1051 and KDM-1156) showing drought tolerance. Exploitation of identified elite lines in a crossing program involving all possible combinations would help to develop hybrids with inbuilt mechanism to drought tolerance. Markers viz., umc -1766, umc-1478 and phi-061 recorded PIC >8 and alleles per locus more than 9 and therefore, discriminated the set of lines more efficiently. Genotyping data complemented by morpho- hysiological parameters were used to identify a number of pair-wise combinations for the development of mapping population segregating for drought tolerance and potential heterotic pairs for the development of drought tolerant hybrids.

    Neutrino Induced Upward Going Muons from a Gamma Ray Burst in a Neutrino Telescope of Km^2 Area

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    The number of neutrino induced upward going muons from a single Gamma Ray Burst (GRB) expected to be detected by the proposed kilometer scale IceCube detector at the South Pole location has been calculated. The effects of the Lorentz factor, total energy of the GRB emitted in neutrinos and its distance from the observer (red shift) on the number of neutrino events from the GRB have been examined. The present investigation reveals that there is possibility of exploring the early Universe with the proposed kilometer scale IceCube neutrino telescope.Comment: 18pages, 5 figures. Physical Review D in pres

    Effect of Pulsing Treatments for Enhancing Shelf-Life of Cut Asiatic Lilium cv. Elite

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    Studies were conducted on cut Asiatic Lilium cv. Elite to assess the effectiveness of various floral preservatives as pulsing treatments for delaying senescence and prolonging vase life. Uniform spikes of lilium at bud colour break stage were brought to the laboratory in the morning and placed in 8 different pulsing solutions consisting of sucrose (Suc) 5%, aluminium sulphate (AS) 400 ppm, silver thio-sulphate (STS) 2.0 mM and citric acid (CA) 1000 ppm alone and in combination with sucrose. Distilled water without any chemical served as the control. Among individual treatments, STS 2.0 mM maintained better water relations and flower quality compared to others. STS also showed superiority over other treatments when combined with Suc 5% by providing largest flower size (16.74 cm) with maximum vase life (17.29 days) owing to most-favourable water relations parameters
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