Scaling and Formulary cross sections for ion-atom impact ionization

The values of ion-atom ionization cross sections are frequently needed for many applications that utilize the propagation of fast ions through matter. When experimental data and theoretical calculations are not available, approximate formulas are frequently used. This paper briefly summarizes the most important theoretical results and approaches to cross section calculations in order to place the discussion in historical perspective and offer a concise introduction to the topic. Based on experimental data and theoretical predictions, a new fit for ionization cross sections is proposed. The range of validity and accuracy of several frequently used approximations (classical trajectory, the Born approximation, and so forth) are discussed using, as examples, the ionization cross sections of hydrogen and helium atoms by various fully stripped ions.Comment: 46 pages, 8 figure

Locating the Source of Diffusion in Large-Scale Networks

How can we localize the source of diffusion in a complex network? Due to the tremendous size of many real networks--such as the Internet or the human social graph--it is usually infeasible to observe the state of all nodes in a network. We show that it is fundamentally possible to estimate the location of the source from measurements collected by sparsely-placed observers. We present a strategy that is optimal for arbitrary trees, achieving maximum probability of correct localization. We describe efficient implementations with complexity O(N^{\alpha}), where \alpha=1 for arbitrary trees, and \alpha=3 for arbitrary graphs. In the context of several case studies, we determine how localization accuracy is affected by various system parameters, including the structure of the network, the density of observers, and the number of observed cascades.Comment: To appear in Physical Review Letters. Includes pre-print of main paper, and supplementary materia

Genetic Mechanisms Underlying the Pathogenicity of Cold-Stressed Salmonella Enterica Serovar Typhimurium in Cultured Intestinal Epithelial Cells

Salmonella encounters various stresses in the environment and in the host during infection. The effects of cold (5 C, 48 h), peroxide (5 mM H2O2, 5 h) and acid stress (pH 4.0, 90 min) were tested on pathogenicity of Salmonella. Prior exposure of Salmonella to cold stress significantly (P \u3c 0.05) increased adhesion and invasion of cultured intestinal epithelial (Caco-2) cells. This increased Salmonella-host cell association was also correlated with significant induction of several virulence-associated genes, implying an increased potential of cold-stressed Salmonella to cause an infection. In Caco-2 cells infected with cold-stressed Salmonella, genes involved in the electron transfer chain were significantly induced, but no simultaneous significant increase in expression of antioxidant genes that neutralize the effect of superoxide radicals or reactive oxygen species was observed. Increased production of caspase 9 and caspase 3/7 was confirmed during host cell infection with cold-stressed Salmonella. Further, a prophage gene, STM2699, induced in cold-stressed Salmonella and a spectrin gene, SPTAN1, induced in Salmonella-infected intestinal epithelial cells were found to have a significant contribution in increased adhesion and invasion of cold-stressed Salmonella in epithelial cells

Acute kidney injury and its outcome in obstetrics

Background: Acute kidney injury occurring during pregnancy, labour, delivery, and/or postpartum period. Proper management of AKI (acute kidney injury) is challenging because (i) both maternal and fetal health must be considered and (ii) the cardiovascular and renal adaptations of pregnancy add to the complexity for management.Methods: The objective of this study was to study association and contributing factors in AKI, a retrospective study of 20 cases of AKI complicating pregnancies carried out in department of obstetrics and gynecology, SVPIMSR over a period of 12 months and results were studied and analysed. Etiological factors, associated liver pathology, coagulation abnormality, thrombocytopenia, sepsis, recovery status and fetomaternal outcome were studied and tabulated. AKI was analysed in terms of maximal stage of renal injury attained as per risk, injury, failure, loss of function, and end-stage renal disease (RIFLE) criteria.Results: The incidence of ARF (acute renal failure) in pregnancy was about 0.3%. Hypertensive disorders were the major causative factor. Amongst the 20 cases, 8 cases were referred from outside and two of them died. Total 5 of 20 cases required hemodialysis and two of them had partial recovery.Conclusions: AKI complicating pregnancies are not uncommon. If recognized and treated promptly, recovery is assured in majority of cases. Early identification and prompt management of pre-eclampsia and sepsis can prevent majority of cases. Ultrasonography revelation of placenta previa or abruption helps in early management eventually decreases the chances of bleeding which is one of the causes of AKI (pre-renal cause)

Construction and Validation of Nepali Teachers’ Self-Efficacy and Classroom Management Practices Instruments Through the E-Delphi Technique

This study presents the processes applied in developing and validating Nepali Classroom Management Practices (CMPS) and Nepali Teachers’ Self-Efficacy (NTSE) instruments. The instruments were developed using the e-Delphi technique. To find the consensus benchmark of the responses, the study used a five-point Likert scale and used Microsoft Excel to analyze responses. The items that achieved a 75% consensus were accepted. Following the interviews and two rounds of questionnaire administration, 28 items from the initial 35 for NTSE and 24 items from the initial 52 for CMP were found to have a high consensus among the experts. Therefore, 28-items NTSE and 24-items CMP instruments were developed to measure Nepali public school teachers’ self-efficacy and their classroom management practices. The pilot study results demonstrated that there was strong internal consistency of items with the value of the overall Cronbach’s alpha in both scales α= .86 (NTSE α = .77 and CMP α = .83). These scales can be used for educational research projects in Nepal and then be contextualized to use in other countries

Liquisolid Compacts: A Review

Solubility is a major problem for nearly one third drugs in their development phase. Liquisolid technique is a most promising technique for promoting dissolution by increase in solubility. Liquisolid compact technology is a novel concept for oral drug delivery. Liquisolid compact technology was first described by spireas et.al. (1998). According to the new formulation method of liqui-solid compacts, liquid medications such as solutions or suspensions of water insoluble drugs in suitable nonvolatile liquid vehicles can be converted into acceptably flowing and compressible powders by blending with selected powder excipients