Massive Dirac fermions and the zero field quantum Hall effect

Through an explicit calculation for a Lagrangian in quantum electrodynamics in (2+1)-space--time dimensions (QED$_3$), making use of the relativistic Kubo formula, we demonstrate that the filling factor accompanying the quantized electrical conductivity for massive Dirac fermions of a single species in two spatial dimensions is a half (in natural units) when time reversal and parity symmetries of the Lagrangian are explicitly broken by the fermion mass term. We then discuss the most general form of the QED$_3$ Lagrangian, both for irreducible and reducible representations of the Dirac matrices in the plane, with emphasis on the appearance of a Chern-Simons term. We also identify the value of the filling factor with a zero field quantum Hall effect (QHE).Comment: 15 pages. Accepted in Jour. Phys.

Invariant Variational Problems

This research is the study of conservation laws using Lie algebra of the symmetry Lie group. In particular, we consider conservation laws for invariant variational problems based on Noether theorem. We have provided a formula of conservation laws in terms of the Lie algebra of symmetry Lie group. &nbsp

The nonperturbative propagator and vertex in massless quenched QED_d

It is well known how multiplicative renormalizability of the fermion propagator, through its Schwinger-Dyson equation, imposes restrictions on the 3-point fermion-boson vertex in massless quenched quantum electrodynamics in 4-dimensions (QED$_4$). Moreover, perturbation theory serves as an excellent guide for possible nonperturbative constructions of Green functions. We extend these ideas to arbitrary dimensions $d$. The constraint of multiplicative renormalizability of the fermion propagator is generalized to a Landau-Khalatnikov-Fradkin transformation law in $d$-dimensions and it naturally leads to a constraint on the fermion-boson vertex. We verify that this constraint is satisfied in perturbation theory at the one loop level in 3-dimensions. Based upon one loop perturbative calculation of the vertex, we find additional restrictions on its possible nonperturbative forms in arbitrary dimensions.Comment: 13 pages, no figures, latex (uses IOP style files

Antimicrobial studies of unsymmetrical bis-1,2,3-triazoles

Aryl azides were treated with allenylmagnesium bromide to generate 1,5-disubstituted butynyl 1,2,3-triazoles in a domino fashion, which upon Cu(I) catalyzed 1,3-dipolar cycloaddition with aryl azides afforded novel bis-1,2,3-triazoles in quantitative yields. The final products were analyzed for their antimicrobial activities against a panel of bacterial and fungal strains which revealed the products to be potent antimicrobials

In Vitro Effects of Some Insecticides on Rumen Fluid Fermentation

A study to investigate the effects of different levels (0,5,10 and 15ppm) of three insecticides (Endosulfan, Phosalone and Chlorpyrifos) on rumen fluid fermentation characteristics (rumen pH, rumen ammonia, rumen V FA and in vitro dry matter disappearance) was carried out in the laboratory of biology in the University of Gezira, Wad Medani, Sudan in 1998. The study indicated that all the levels of each insecticide significantly (P<0.05) inhibited the in vitro dry matter disappearance )IVDMD), the rumen fluid volatile fatty acids and the rumen fluid total protozoa, and elevated the rumen fluid ammonia compared to the control. However, the rumen fluid pH was not affected. Also, the study revealed that endosulfan significantly (P<0.05) inhibited the rumen protozoa and the IVDMD percent than both phosalpne and chlorpyrifos

An audit of head trauma care and mortality

Objective: To analyze the factors contributing to deaths from head trauma by using standardized assessment parameters and to provide a peer-review of head injury deaths with focus on identifying deficiencies and analyzing contributory factors.Design: Descriptive study.Place and duration of study: The study was carried out at the Emergency, Aga Khan University Hospital during January 1998 to December 1999.Subjects and method: One hundred and three patients above the age of 15 years presenting alive to the Aga Khan University Hospital (AKUH) emergency with head injury were included in this study. Identified deaths data was reviewed by the Hospital Trauma Peer Review Committee and consensus arrived at for categorization of deaths. The potential deficiencies in care were identified and final recommendations made. The data was computed on CDC Trauma Registry (V 3.0) and SPSS (V 8.0).Results: Mean age was 31.9 years (n=103) with predominant male population (4:1). Severe head injury (GCS\u3c8) accounted for 21.3 % (n=22) of all cases with a total number of deaths being 12.6 % (n=13). Deaths were categorized preventable in 3 cases with non-preventable and potentially preventable in 4 and 6 cases respectively. Road traffic accidents were the predominant mechanism (n=8) in all deaths (n=13). The time interval in relation to mortality was biphasic, most deaths occurring either within 24 hours or between 3-7 days of injury. Inappropriate pre-hospital treatment, pre-hospital delays and inappropriate mode of transportation without inter-hospital communication were the process-related defects in pre-hospital care with major determinant of deaths outside AKUH (n=5). Prolonged emergency stay, delayed intensive care availability were the process-related deficiencies whereas inappropriate initial resuscitation, inappropriate initial head injury management were provider-related deficiencies in in-hospital care.Conclusion: Transfer of inappropriately managed patients, lapses in inter-hospital communications, delayed transfers were identified as the major pre-hospital factors whereas lack of ICU beds, portable ventilators in emergency room, delays in CT scan facilities were the deficiencies in the hospital services. Opportunities for improvement in head trauma care are needed to focus on initial resuscitation and appropriate surgical management

Mapping Risk Assessment Strategy for COVID-19 Mobile Apps’ Vulnerabilities

Recent innovations in mobile technologies are playing an important and vital role in combating the COVID-19 pandemic. While mobile apps’ functionality plays a crucial role in tackling the COVID-19 spread, it is also raising concerns about the associated privacy risks that users may face. Recent research studies have showed various technological measures on mobile applications that lack consideration of privacy risks in their data practices. For example, security vulnerabilities in COVID-19 apps can be exploited and therefore also pose privacy violations. In this paper, we focus on recent and newly developed COVID-19 apps and consider their threat landscape. Our objective was to identify security vulnerabilities that can lead to user-level privacy risks. We also formalize our approach by measuring the level of risk associated with assets and services that attackers may be targeting to capture during the exploitation. We utilized baseline risk assessment criteria within the scope of three specific security vulnerabilities that often exists in COVID-19 applications namely credential leaks, insecure communication, and HTTP request libraries. We present a proof of concept implementation for risk assessment of COVID-19 apps that can be utilized to evaluate privacy risk by the impact of assets and threat likelihood.Ope

Neonatal mortality in Sudan: analysis of the Sudan household survey, 2010

BACKGROUND: Sudan is classified as having insufficient progress in achieving the Millennium Development Goal (MDG-4), where the levels of child and infant mortality are among the highest in the region and the world. This study investigated factors associated with neonatal mortality in Sudan. Neonatal death is defined as death within the first 28 days of life. METHODS: This study analysed data from the Sudan Household Health Survey 2nd round, which was carried out in 2010. Total of 6,198 live-born infants delivered within the two years preceding the survey were included as the study population. Multivariate logistic regression was used to model neonatal mortality as a function of maternal health parameters, socioeconomic indicators and the sex of the child. RESULTS: There were 189 neonatal deaths out of 6,198 live births (3.0%). In the multiple logistic regression, the factors associated with neonatal mortality were advanced maternal age (≥ 40 years; OR = 2.4; 95% CI: 1.21, 4.78, p = 0.012), poor household wealth index (OR = 1.6; 95% CI: 1.18, 2.47, p = 0.005), male child (OR = 1.8; 95% CI: 1.31, 2.42, p < 0.001), delivery of baby by Caesarean section (OR = 1.6; 95% CI: 1.78, 2.42, p = 0.013) and delivery complications (OR = 1.4; 95% CI: 1.18, 2.15, p = 0.002). CONCLUSION: Public health interventions which target neonatal mortality reduction should adopt a risk-factor-based approach to detect pregnancy complications early and once identified, the health system should be strengthened so that these complications can be dealt with adequately

Prevalence of ultrasonography proved polycystic ovaries in North Indian women with type 2 diabetes mellitus

BACKGROUND: Polycystic ovaries (PCO) and their clinical expression (the polycystic ovary syndrome [PCOS]) as well as type 2 diabetes mellitus (T2DM) are common medical conditions linked through insulin resistance. We studied the prevalence of PCO and PCOS in women with diet and/or oral hypoglycemic treated T2DM and non-diabetic control women. DESIGN: Prospective study. METHODS: One hundred and five reproductive age group women with diet and /or oral hypoglycemic treated T2DM were the subjects of the study. Sixty age-matched non-diabetic women served as controls. Transabdominal ultrasonographic assessment of the ovaries was used to diagnose PCO. Clinical, biochemical and hormonal parameters were also noted. RESULTS: Ultrasonographic prevalence of PCO was higher in women with diabetes than in non-diabetic subjects (61.0% vs. 36.7%, P < 0.003) whereas that of PCOS was 37.1% in diabetic subjects and 25% in non-diabetic controls (P > 0.1). Diabetic women with PCO had diabetes of significantly longer duration than those without PCO (4.19±2.0 versus 2.9±1.6 yrs; p < 0.05). Among both diabetic and non-diabetic women, those with PCO had significantly higher plasma LH, LH/FSH ratio, total testosterone and androstenedione levels. CONCLUSION: This study demonstrates a higher prevalence of PCO in women with T2DM as compared to non-diabetic subjects