22 research outputs found
Space-filling, multi-fractal, localized thermal spikes in silicon, germanium and zinc oxide
The mechanism responsible for the emission of clusters from heavy ion
irradiated solids is proposed to be thermal spikes. Collision cascade-based
theories describe atomic sputtering but cannot explain the consistently
observed experimental evidence for significant cluster emission. Statistical
thermodynamic arguments for thermal spikes are employed here for qualitative
and quantitative estimation of the thermal spike-induced cluster emission from
silicon, germanium and zinc oxide. The evolving cascades and spikes in
elemental and molecular semiconducting solids are shown to have fractal
characteristics. Power law potential is used to calculate the fractal
dimension.The fractal dimension is shown to be dependent upon the exponent of
the power law interatomic potential. Each irradiating ion has the probability
of initiating a space-filling, multi-fractal thermal spike that may sublime a
localized region near the surface by emitting clusters in relative ratios that
depend upon the energies of formation of respective surface vacancies.Comment: 16 pages, 6 figure
Credit Risk Management Practices Used by Banks in Agricultural Finance: A Case Study of Pakistan
Purpose: Agricultural sector is an important sector of Pakistan’s economy. Agriculture plays a significant role in the economic development of Pakistan. Its contribution to GDP is about 23% and approximately 60% of Pakistan’s total population live in the rural areas and most of them earn their livelihood from agriculture. Due to the green revolution, rapid changes have been occurring in production technologies, and methods have been changed. As more capital is required to adopt these methods and technologies, so the small farmers cannot afford these methods. They need finances for production and investment purpose. The small farmer has very limited ability to agricultural finance for both production and investment needs and they are facing a shortfall of credit. Banks hesitate to grant agriculture credit because of higher credit risk. The main purpose of this research paper is to find out the credit risk faced by the banks of Pakistan and risk management techniques used by these banks. Research methodology: This research is basically quantitative in nature, and a Standard questionnaire is used for the collection of data on credit risk and its management techniques from the banks. A sample of 45 bank branches of 17 banks that grant agriculture credit has been taken and questionnaire were being filled by credit officers of the agricultural sections of these banks. The Frequency distribution technique was applied through SPSS 17 to analyze and finalize the results. Findings: The major findings of this research are: 82.2% of banks had faced the situation of credit risk in which farmers failed to pay back the credit to the bank. 53.3% respondents considered the production, price and policy risk together affect all the farmers in a particular geographical area. 35% considered ‘’willful rejection risk” as an important risk that arises due to an individual farmer. 60% respondents use the crop insurance for the management of production risk. 48.9% bank used no technique for the management of price risk. 75.6% respondents suggest that the improvement in laws and policies on land ownership will help in credit risk management. 60% respondent does not insure the life of a farmer. 77.8% use collateral management for the management of “willful rejection risk”. According to 75.6% respondent’s fire/theft insurance of agricultural asset will help to manage this risk. Originality /Value: The value of this research paper is that it gives us an idea about the credit risk faced and its management techniques used by the banks of Pakistan. It also gives us an idea about the credit risk management techniques which are being used in the world but not in the Pakistan. Research Implications: The research implications of this paper are to increase the understanding of factors which are the basis for credit risk in agricultural financing and its management techniques used by the banks of Pakistan. Paper Type: Research Paper Keywords: agricultural finance, credit risk, Risk management practices, crop insurance, highly correlated risk, localized risk, price smoothing
Predictors of Early Seizures After First Acute Stroke
ABSTRACT
Background and objective: There is a lack of local data regarding the frequency and predictors of early seizures after stroke. The objective of this study was to determine the frequency of early seizures after stroke and identify the predictors which lead to them after first acute stroke.
Methods: This cross-sectional observational study was conducted in the Department of Neurology, Pakistan Institute of Medical Sciences, Islamabad from October 2021 to June 2022. A total of 310 consecutive eligible patients of acute stroke were recruited. Key inclusion criteria included any patient of \u3e20 years of age with confirmed diagnosis of stroke on imaging, non-traumatic, with no history of seizures in past. Data was analyzed by SPSS version 23.0.
Results: The mean age of patients in the seizures group was 48.40 ± 20.9 years. Hypertension was the most common co-morbid present in 225 (76.5%) patients. Early seizures were found in 52 (16.8%) patients with 42 (80.76%) having seizures in first 24 hours of stroke (p value 0.001). On National Institute of Health Sciences Scale (NIHSS) score most patients 125 (40.3%) had moderate severity score i.e. score in between 7 to 25 (p value 0.05). Ischemic stroke was identified as the stroke variety with most of the early seizures i.e. 16 (30.76%) (p value 0.003). Conclusion: Early seizures were not infrequent after acute stroke (16.77%) in our study. Early seizures were associated with younger age, cortical region lesion, ischemic stroke, followed by cerebral venous thrombosis. Higher NIHSS score and greater disability was associated with increased incidence of early seizures
Hypodensities Within Hematoma Predict Outcome After Spontaneous Intracerebral Hemorrhage
ABSTRACT
Background and objective: Radial nerve is injured due to a variety of reasons. The objective of this study was to determine the clinical spectrum, risk factors and electrophysiologic aspect of radial nerve injury presenting to a tertiary care hospital in Lahore.
Methods: This descriptive prospective cross-sectional study was conducted at department of Neurology, Mayo hospital Lahore from July 2022 to December 2022 and comprised patients with isolated radial nerve injury on the basis of history and clinical examination regardless of their gender, above 15 years of age. NCS/EMG was done on a Japanese machine Nihon Kohden by an expert as per recommended protocol for electrodiagnostic evaluation of a suspected radial nerve injury and interpreted by consultant neurologist.
Results: Of 75 patients, 52(69.3%) were males and 23(30.7%) were females. The most common etiology turned out to be misplaced intramuscular injection in 45(60%) of the patients. The site of lesion in most cases was in the spiral groove in 36 (40%) of the patient. Most of the patients i.e. 71(94.7%) had a wrist drop. Evidence of reinnervation was present in 30(40%) of patients.
Conclusion: Most cases of radial nerve injury presented with a wrist drop in which the commonest etiology was misplaced intramuscular injection. The site of lesion in most cases turned out to at the level of spiral groove, and the nature of lesion was primarily axonal loss followed by secondary demyelination
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Global burden of 288 causes of death and life expectancy decomposition in 204 countries and territories and 811 subnational locations, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021
BACKGROUND Regular, detailed reporting on population health by underlying cause of death is fundamental for public health decision making. Cause-specific estimates of mortality and the subsequent effects on life expectancy worldwide are valuable metrics to gauge progress in reducing mortality rates. These estimates are particularly important following large-scale mortality spikes, such as the COVID-19 pandemic. When systematically analysed, mortality rates and life expectancy allow comparisons of the consequences of causes of death globally and over time, providing a nuanced understanding of the effect of these causes on global populations. METHODS The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 cause-of-death analysis estimated mortality and years of life lost (YLLs) from 288 causes of death by age-sex-location-year in 204 countries and territories and 811 subnational locations for each year from 1990 until 2021. The analysis used 56 604 data sources, including data from vital registration and verbal autopsy as well as surveys, censuses, surveillance systems, and cancer registries, among others. As with previous GBD rounds, cause-specific death rates for most causes were estimated using the Cause of Death Ensemble model-a modelling tool developed for GBD to assess the out-of-sample predictive validity of different statistical models and covariate permutations and combine those results to produce cause-specific mortality estimates-with alternative strategies adapted to model causes with insufficient data, substantial changes in reporting over the study period, or unusual epidemiology. YLLs were computed as the product of the number of deaths for each cause-age-sex-location-year and the standard life expectancy at each age. As part of the modelling process, uncertainty intervals (UIs) were generated using the 2·5th and 97·5th percentiles from a 1000-draw distribution for each metric. We decomposed life expectancy by cause of death, location, and year to show cause-specific effects on life expectancy from 1990 to 2021. We also used the coefficient of variation and the fraction of population affected by 90% of deaths to highlight concentrations of mortality. Findings are reported in counts and age-standardised rates. Methodological improvements for cause-of-death estimates in GBD 2021 include the expansion of under-5-years age group to include four new age groups, enhanced methods to account for stochastic variation of sparse data, and the inclusion of COVID-19 and other pandemic-related mortality-which includes excess mortality associated with the pandemic, excluding COVID-19, lower respiratory infections, measles, malaria, and pertussis. For this analysis, 199 new country-years of vital registration cause-of-death data, 5 country-years of surveillance data, 21 country-years of verbal autopsy data, and 94 country-years of other data types were added to those used in previous GBD rounds. FINDINGS The leading causes of age-standardised deaths globally were the same in 2019 as they were in 1990; in descending order, these were, ischaemic heart disease, stroke, chronic obstructive pulmonary disease, and lower respiratory infections. In 2021, however, COVID-19 replaced stroke as the second-leading age-standardised cause of death, with 94·0 deaths (95% UI 89·2-100·0) per 100 000 population. The COVID-19 pandemic shifted the rankings of the leading five causes, lowering stroke to the third-leading and chronic obstructive pulmonary disease to the fourth-leading position. In 2021, the highest age-standardised death rates from COVID-19 occurred in sub-Saharan Africa (271·0 deaths [250·1-290·7] per 100 000 population) and Latin America and the Caribbean (195·4 deaths [182·1-211·4] per 100 000 population). The lowest age-standardised death rates from COVID-19 were in the high-income super-region (48·1 deaths [47·4-48·8] per 100 000 population) and southeast Asia, east Asia, and Oceania (23·2 deaths [16·3-37·2] per 100 000 population). Globally, life expectancy steadily improved between 1990 and 2019 for 18 of the 22 investigated causes. Decomposition of global and regional life expectancy showed the positive effect that reductions in deaths from enteric infections, lower respiratory infections, stroke, and neonatal deaths, among others have contributed to improved survival over the study period. However, a net reduction of 1·6 years occurred in global life expectancy between 2019 and 2021, primarily due to increased death rates from COVID-19 and other pandemic-related mortality. Life expectancy was highly variable between super-regions over the study period, with southeast Asia, east Asia, and Oceania gaining 8·3 years (6·7-9·9) overall, while having the smallest reduction in life expectancy due to COVID-19 (0·4 years). The largest reduction in life expectancy due to COVID-19 occurred in Latin America and the Caribbean (3·6 years). Additionally, 53 of the 288 causes of death were highly concentrated in locations with less than 50% of the global population as of 2021, and these causes of death became progressively more concentrated since 1990, when only 44 causes showed this pattern. The concentration phenomenon is discussed heuristically with respect to enteric and lower respiratory infections, malaria, HIV/AIDS, neonatal disorders, tuberculosis, and measles. INTERPRETATION Long-standing gains in life expectancy and reductions in many of the leading causes of death have been disrupted by the COVID-19 pandemic, the adverse effects of which were spread unevenly among populations. Despite the pandemic, there has been continued progress in combatting several notable causes of death, leading to improved global life expectancy over the study period. Each of the seven GBD super-regions showed an overall improvement from 1990 and 2021, obscuring the negative effect in the years of the pandemic. Additionally, our findings regarding regional variation in causes of death driving increases in life expectancy hold clear policy utility. Analyses of shifting mortality trends reveal that several causes, once widespread globally, are now increasingly concentrated geographically. These changes in mortality concentration, alongside further investigation of changing risks, interventions, and relevant policy, present an important opportunity to deepen our understanding of mortality-reduction strategies. Examining patterns in mortality concentration might reveal areas where successful public health interventions have been implemented. Translating these successes to locations where certain causes of death remain entrenched can inform policies that work to improve life expectancy for people everywhere. FUNDING Bill & Melinda Gates Foundation
Coronavirus Genomes and Unique Mutations in Structural and Non-Structural Proteins in Pakistani SARS-CoV-2 Delta Variants during the Fourth Wave of the Pandemic
Genomic epidemiology of SARS-CoV-2 is imperative to explore the transmission, evolution, and also pathogenicity of viruses. The emergence of SARS-CoV-2 variants of concern posed a severe threat to the global public health efforts. To assess the potential consequence of these emerging variants on public health, continuous molecular epidemiology is of vital importance. The current study has been designed to investigate the major SARS-CoV-2 variants and emerging mutations in virus structural and non-structural proteins (NSP) during the fourth wave in September 2021 from the Punjab province of Pakistan. Twenty SARS-CoV-2 positive samples have been collected from major cities were subjected to next-generation sequencing. Among the 20 whole genomes (GenBank Accession SRR16294858-SRR16294877), 2 samples failed to be completely sequenced. These genome sequences harbored 207 non-synonymous mutations, among which 19 were unique to GISAID. The genome sequences were detected: Delta 21I, 21J variants (B.1.617.2). Mutation’s spike_F157del, spike_P681R, spike_T478K, spike_T19R, spike_L452R, spike_D614G, spike_G142D, spike_E156G, and spike_R158del have been detected in all samples where K1086Q, E554K, and C1250W were unique in spike protein. These genomic sequences also harbored 129 non-synonymous mutations in NSP. The most common were NSP3_P1469S (N = 17), NSP3_A488S (N = 17), NSP3_P1228L (N = 17), NSP4_V167L (N = 17), NSP4_T492I (N = 17), NSP6_T77A (N = 17), NSP14_A394V (N = 17), NSP12_G671S (N = 18), and NSP13_P77L (N = 18). The mutation, F313Y in NSP12, detected in the current study, was found in a single isolate from Belgium. Numerous other unique mutations have been detected in the virus papain-like protease (NSP3), main protease (NSP5), and RNA-dependent RNA polymerase (NSP12). The most common non-synonymous mutations in the spike protein were subjected to stability analysis, exhibiting a stabilizing effect on structures. The presence of Delta variants may affect therapeutic efforts and vaccine efficacy. Continuous genomic epidemiology of SARS-CoV-2 in Pakistan may be useful for better management of SARS-CoV-2 infections
Quantitation of Multipartite Banana Bunchy Top Virus Genomic Components and Their Transcripts in Infected Tissues of Banana (<i>Musa acuminata</i>)
Banana bunchy top disease (BBTD), caused by a Banana Bunchy Top Virus (BBTV), is the most devastating viral disease of bananas. The genome of multipartite BBTV is about 1 Kb in size and comprises six circular single-stranded (ss) DNA components, namely DNA-R, C, S, M, U3, and N. Gene expression in multipartite DNA viruses is highly flexible due to variations in the copy number and transcript levels of individual genomic components. This enables them to adapt to changing conditions and maintain optimal fitness. In the current study, the copy number of each genetic component of BBTV and its transcript level were determined in the leaf, midrib, and root tissue of the infected banana plant. The results of the study showed that DNA copies (copies/ng) were higher in midrib (11,105 ± 10,704.42), followed by leaf (6902.91 ± 1651.14), and were lowest in root (23.49 ± 9.21) tissues. In contrast, the transcript level was highest in the root (312.45 ± 106.69) and lowest in the midrib (0.72 ± 0.16). This suggests that BBTV independently regulates the transcriptional level of each DNA component. The distribution of BBTV in different tissues assists the identification of significantly higher viral load tissues for early and sensitive disease diagnosis, which will be beneficial for better disease management
Influence of heterogeneous media on Very High Energy Electron (VHEE) dose penetration and a Monte Carlo-based comparison with existing radiotherapy modalities
• First experimental demonstration of the relative insensitivity of VHEE beams to inhomogeneities. • Topas/GEANT4 simulations on experiments conducted at CERN’s CLEAR facility are in good agreement. • Simulations of proton beams and demonstrate their relative sensitivity to inhomogeneities. • Relative dose insensitivity of several tissue-like equivalents have been explored. • Dose penetration for Very High Electron (VHEE) beams explored