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

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

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

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

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

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

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

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

Changing histological spectrum of adult nephrotic syndrome in comparison to previous study: single centre analysis

Background: Glomerular diseases are an important cause of chronic renal failure in developing countries. The spectrum of diseases causing nephrotic syndrome is changing globally in the last few decades. Methods: Patients in the age group 18-60 years with nephrotic syndrome were consecutively included in the study. Renal biopsies were performed in all patients and were subjected to light microscopy, immunofluorescence (IF) and electron microscopy (EM). Results: 189 patients (67% males) were included in the study. The mean age was 43 years. Primary glomerular diseases accounted for 92.5% of cases while lupus nephritis was the most common secondary glomerular disease. Focal segmental glomerulosclerosis (FSGS) accounted for 28.6% of primary glomerular diseases making it the most common cause of nephrotic syndrome. It was followed by membranous glomerulonephritis (MGN) in 13.2%, membranoproliferative glomerulonephritis in 11.2%, diffuse proliferative glomerulonephritis in 10.6% and minimal change disease in 9.5%. Conclusions: The biopsy diagnosis of FSGS has increased considerably in last few decades and it is now the most common cause of nephrotic syndrome in adults in North India. MGN is the most common lesion in patients over 40 years of age

Set-up saving schemes for printed circuit boards assembly

Focusing on a basic printed circuit board (PCB) assembly line configuration characterized by very long set-up times, we examine two scheduling methods that can significantly reduce the set-up. Both methods -the Grouped Set-Up (GSU) method that has been recently introduced in the literature and the Sequence Dependent Scheduling (SDS) method, which has not been studied in this context -are based on component commonality among PCB types. Using the typical traditional scheduling method as a benchmark, the GSU and the SDS methods are compared in terms of three performance measures: line throughput, average work-in-process (WIP) inventory level, and implementation complexity. Guidelines for selecting the most appropriate method for a given production environment are proposed. The analysis is illustrated using real data from a typical production line