Mark-Recapture Creel Survey and Survival Models

In this dissertation, we consider a model based approach to the estimation of exploitation rate of a fish population by combining mark-recapture procedures with a creel survey. We also consider the analysis of a proportional hazards survival model for randomly censored observations, known as the Koziol-Green model. The model assumes that the lifetime survivor function is a power of the censored time survivor function. In Chapter 2, we introduce the model based approach to the estimation of the exploitation rate of a fish population by combining mark-recapture procedures with a creel survey. We assume that in the beginning of a fishing season M number of fishes are captured, marked and then released back into the population. Also, there are N available sampling units out of which n are sampled by the creel survey agents. The agents observe the number of fish captured with and without tags in each sampled unit. We make two basic assumptions, (1) the number captured in each unit follows a Poisson distribution and (2) the number recaptured given the number captured in each unit follows a binomial distribution. We obtain the maximum likelihood estimator and the moment estimator of the exploitation rate. We also compare the performance of these two estimators. In Chapter 3, the model based approach of Chapter 2 is extended to the case where the space-time units of the fisheries are stratified according to the different fishing areas or seasons. In Chapter 4, we consider the Koziol-Green survival model with the lifetimes following a Weibull distribution. We consider the Bayesian analysis of this model by specifying parametric prior distributions for the parameters of the model. The method of Gibbs sampler is used for Bayesian computations. The Bayes estimator is compared with the maximum likelihood estimator of the survivor function. In Chapter 5, we incorporate covariates in the Koziol-Green model and study their effect on the lifetimes. We consider maximum likelihood estimation of the parameters of this model

Factors Influencing Customers’ Expectation Towards Green Banking Practices in Bangladesh

Green banking, considered as sustainable banking practices, has created incessant buzz among banks and financial institutions which are consistently seeking an exhaustive framework to sustain in dreadful environmental changes. Attachments to green strategies upraise customers’ interests and expectations on enterprises’ environmental responsibilities. The article dwells on addressing the factors impacting customers’ expectations towards green banking practices from the perspective of banking industry in Bangladesh. Total 246 samples have been finalized from target population using simple random sampling. The survey has used five (5) point Likert scale and 23 dimensions are identified which are summarized into five factors by using factor analysis. After analysis, it has been found that information availability and customer needs, spirit of ethics and high yield savings, energy efficiency, product benefits as well as integration and personalization- these five prominent factors are responsible for influencing customers’ expectations towards green banking practices in Bangladesh. The study offers an insight into what banks should do, being environmentally proactive, to create a strong customer base in future. Keywords: Green Banking, Customer Expectation, Sustainable Busines

Implementing Man-in-the-Middle Attack to Investigate Network Vulnerabilities in Smart Grid Test-bed

The smart-grid introduces several new data-gathering, communication, and information-sharing capabilities into the electrical system, as well as additional privacy threats, vulnerabilities, and cyber-attacks. In this study, Modbus is regarded as one of the most prevalent interfaces for control systems in power plants. Modern control interfaces are vulnerable to cyber-attacks, posing a risk to the entire energy infrastructure. In order to strengthen resistance to cyber-attacks, this study introduces a test bed for cyber-physical systems that operate in real-time. To investigate the network vulnerabilities of smart power grids, Modbus protocol has been examined combining a real-time power system simulator with a communication system simulator and the effects of the system presented and analyzed. The goal is to detect the vulnerability in Modbus protocol and perform the Man-in-the-middle attack with its impact on the system. This proposed testbed can be evaluated as a research model for vulnerability assessment as well as a tool for evaluating cyber-attacks and enquire into any detection mechanism for safeguarding and defending smart grid systems from a variety of cyberattacks. We present here the preliminary findings on using the testbed to identify a particular MiTM attack and the effects on system performance. Finally, we suggest a cyber security strategy as a solution to address such network vulnerabilities and deploy appropriate countermeasures.Comment: 7 pages, 10 figures, Conference paper, Accepted in publication for 2023 IEEE World AI IoT Congress (AIIoT

Role of offending out-door aero-allergen and CD14 C(-159)T polymorphism in development and severity of asthma in a Kolkata patient population

Objective: Present study involved identification of offending out-door aero-allergens and associated genetic pathway in nasso-bronchial asthma among Kolkata population.Methods: Skin-prick test was done among 950 asthmatic patients against 11 common aero-allergens and total serum IgE concentration was measured. PCR-RFLP was done in patients and non-asthmatic control (n=220 in each) to characterize functional polymorphism, C(-159)T, of CD14, a positional candidate gene for allergy. Association of genetic polymorphisms was made with clinico-pathological conditions.Results: We identified Cocos nucifera as the most common aero-allergen sensitizer among atopic patients in Kolkata. Patients with childhood-onset asthma were significantly more sensitive towards aero-allergens and had significantly higher serum IgE level than those of adult-onset (p< 0.0001). No significant difference was found in distribution of SNP genotypes of CD14 among case and control (p=0.178). However among patients, frequency of C allele is significantly higher in childhood-onset group thanthat of adult-onset and concordantly in former CC genotype was associated with significant higher level of serum IgE than CT and TT.Conclusion: In Kolkata, pollen is a common out-door aero-allergen and Cocos nucifera is predominant among pollens. Childhood- onset and adult-onset of asthma showed significant difference in allergen sensitivity as well as genetic background with respect to CD14 polymorphism.Keywords: Asthma, aero-allergen, skin prick test, total IgE, CD14 gene polymorphis

A comparative study of fatty acids profile of two Indian major carps (Gibelion catla, Hamilton, 1822 and Cirrhinus mrigala, Hamilton, 1822) using value added fish feed

Freshwater fishes are not only a major source of protein but they also possess nutritionally valuable lipids in the form of Polyunsaturated fatty acids (PUFAs), which play a crucial role in the normal growth, disease prevention, development, cardiovascular health and reproduction of human. The present study was performed to determine the incorporation rate of fatty acids profile and their composition in two common freshwater carps as Gibelion catla and Cirrhinus mrigala (in situ trial and experimental) in the different experimental time period (0 days, i.e. initial, 90 days and 180 days) by using of value added feed like flaxseed (?-linolenic acids, 51.26% – 54.94%) and soybean oil (?-linolenic acids, 7.95%-9.01%) as omega-3 supplements. To determine the specific growth pattern Length-Weight Relationships (LWRs) are analyzed where it showed positive allometric growth (b=3.20 in 90 days, b=3.11 in 180 days for Catla and b=3.18 in 90 days, b=3.1 in 180 days for Mrigala fish). The Gas Chromatography-Mass Spectrometry (GC/MS) method also confirmed that the percentages of EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) increased significantly (P< 0.05) in experimental (0.096a±0.41, initial; 5.16a±0.27, 90 days; 6.21b±0.36, 180 days Catla fish species and 0.019a±0.96 initial; 3.74b±0.37, 90 days; 3.50a±0.46 180 days for Mrigal fish species) fishes rather than controls (4.28a±0.27, 90 days; 4.36b±0.36, 180 days for Catla species and 2.24b±0.31 90 days; 2.50a±0.11 180 days for Mrigal species). Therefore, it was clearly indicated that formulated diet performed significantly to maintain the positive allometric growth as well as successive enrichment of PUFAs in experimental specimens, which is beneficial for human health as high source of protein and PUFAs as well

Diagnostic value of clinical features to distinguish enteric fever from other febrile illnesses in Bangladesh, Nepal, and Pakistan

Background: Enteric fever, a bacterial infection caused by Salmonella enterica serotypes Typhi and Paratyphi A, frequently presents as a nonlocalizing febrile illness that is difficult to distinguish from other infectious causes of fever. Blood culture is not widely available in endemic settings and, even when available, results can take up to 5 days. We evaluated the diagnostic performance of clinical features, including both reported symptoms and clinical signs, of enteric fever among patients participating in the Surveillance for Enteric Fever in Asia Project (SEAP), a 3-year surveillance study in Bangladesh, Nepal, and Pakistan.Methods: Outpatients presenting with ≥3 consecutive days of reported fever and inpatients with clinically suspected enteric fever from all 6 SEAP study hospitals were eligible to participate. We evaluated the diagnostic performance of select clinical features against blood culture results among outpatients using mixed-effect regression models with a random effect for study site hospital. We also compared the clinical features of S. Typhi to S. Paratyphi A among both outpatients and inpatients.Results: We enrolled 20 899 outpatients, of whom 2116 (10.1%) had positive blood cultures for S. Typhi and 297 (1.4%) had positive cultures for S. Paratyphi A. The sensitivity of absence of cough was the highest among all evaluated features, at 65.5% (95% confidence interval [CI], 55.0-74.7), followed by measured fever at presentation at 59.0% (95% CI, 51.6-65.9) and being unable to complete normal activities for 3 or more days at 51.0% (95% CI, 23.8-77.6). A combined case definition of 3 or more consecutive days of reported fever and 1 or more of the following (a) either the absence of cough, (b) fever at presentation, or (c) 3 or more consecutive days of being unable to conduct usual activity--yielded a sensitivity of 94.6% (95% CI, 93.4-95.5) and specificity of 13.6% (95% CI, 9.8-17.5).Conclusions: Clinical features do not accurately distinguish blood culture-confirmed enteric fever from other febrile syndromes. Rapid, affordable, and accurate diagnostics are urgently needed, particularly in settings with limited or no blood culture capacity

Antibiotic use prior to hospital presentation among individuals with suspected enteric fever in Nepal, Bangladesh, and Pakistan

Background: Antibiotic use prior to seeking care at a hospital may reduce the sensitivity of blood culture for enteric fever, with implications for both clinical care and surveillance. The Surveillance for Enteric Fever in Asia Project (SEAP) is a prospective study of enteric fever incidence in Nepal, Bangladesh, and Pakistan. Nested within SEAP, we evaluated the accuracy of self-reported antibiotic use and investigated the association between antibiotic use and blood culture positivity.Methods: Between November 2016 and April 2019, we collected urine samples among a subset of SEAP participants to test for antibiotic use prior to the hospital visit using an antibacterial activity assay. All participants were asked about recent antibiotic use and had a blood culture performed. We used mixed-effect logit models to evaluate the effect of antimicrobial use on blood culture positivity, adjusted for markers of disease severity.Results: We enrolled 2939 patients with suspected enteric fever. Antibiotics were detected in 39% (1145/2939) of urine samples. The correlation between measured and reported antibiotic use was modest (κ = 0.72). After adjusting for disease severity, patients with antibiotics in their urine were slightly more likely to be blood culture positive for enteric fever; however, the effect was not statistically significant (prevalence ratio, 1.22 [95% confidence interval, .99-1.50]).Conclusions: The reliability of self-reported prior antibiotic use was modest among individuals presenting with fever to tertiary hospitals. While antibiotics are likely to reduce the sensitivity of blood culture, our findings indicate that there is still considerable value in performing blood culture for individuals reporting antibiotic use

Utilization of blood culture in south Asia for the diagnosis and treatment of febrile illness

Background: Blood culture is the current standard for diagnosing bacteremic illnesses, yet it is not clear how physicians in many low- and middle-income countries utilize blood culture for diagnostic purposes and to inform treatment decisions.Methods: We screened suspected enteric fever cases from 6 hospitals in Bangladesh, Nepal, and Pakistan, and enrolled patients if blood culture was prescribed by the treating physician. We used generalized additive regression models to analyze the probability of receiving blood culture by age, and linear regression models to analyze changes by month to the proportion of febrile cases prescribed a blood culture compared with the burden of febrile illness, stratified by hospital. We used logistic regression to analyze predictors for receiving antibiotics empirically. We descriptively reviewed changes in antibiotic therapy by susceptibility patterns and coverage, stratified by country.Results: We screened 30 809 outpatients resulting in 1819 enteric fever cases; 1935 additional cases were enrolled from other hospital locations. Younger outpatients were less likely to receive a blood culture. The association between the number of febrile outpatients and the proportion prescribed blood culture varied by hospital. Antibiotics prescribed empirically were associated with severity and provisional diagnoses, but 31% (1147/3754) of enteric fever cases were not covered by initial therapy; this was highest in Pakistan (50%) as many isolates were resistant to cephalosporins, which were commonly prescribed empirically.Conclusions: Understanding hospital-level communication between laboratories and physicians may improve patient care and timeliness of appropriate antibiotics, which is important considering the rise of antimicrobial resistance

Epidemiology and risk factors for pneumonia severity and mortality in Bangladeshi children <5 years of age before 10-valent pneumococcal conjugate vaccine introduction

Abstract Background Pneumonia is the leading infectious cause of morbidity and mortality in young children in Bangladesh. We present the epidemiology of pneumonia in Bangladeshi children <5 years before 10-valent pneumococcal conjugate vaccine introduction and investigate factors associated with disease severity and mortality. Methods Children aged 2–59 months admitted to three Bangladeshi hospitals with pneumonia (i.e., cough or difficulty breathing and age-specific tachypnea without danger signs) or severe pneumonia (i.e., cough or difficulty breathing and ≥1 danger signs) were included. Demographic, clinical, laboratory, and vaccine history data were collected. We assessed associations between characteristics and pneumonia severity and mortality using multivariable logistic regression. Results Among 3639 Bangladeshi children with pneumonia, 61% had severe disease, and 2% died. Factors independently associated with severe pneumonia included ages 2–5 months (adjusted odds ratio [aOR] 1.60 [95% CI: 1.26–2.01]) and 6–11 months (aOR 1.31 [1.10–1.56]) relative to 12–59 months, low weight for age (aOR 1.22 [1.04–1.42]), unsafe drinking water source (aOR 2.00 [1.50–2.69]), higher paternal education (aOR 1.34 [1.15–1.57]), higher maternal education (aOR 0.74 [0.64–0.87]), and being fully vaccinated for age with pentavalent vaccination (aOR 0.64 [0.51–0.82]). Increased risk of pneumonia mortality was associated with age <12 months, low weight for age, unsafe drinking water source, lower paternal education, disease severity, and having ≥1 co-morbid condition. Conclusions Modifiable factors for severe pneumonia and mortality included low weight for age and access to safe drinking water. Improving vaccination status could decrease disease severity

Healthcare utilization patterns for acute febrile illness in Bangladesh, Nepal, and Pakistan: Results from the surveillance for enteric fever in Asia project

Background: Characterizing healthcare-seeking patterns for acute febrile illness is critical for generating population-based enteric fever incidence estimates from facility-based surveillance data.Methods: We used a hybrid model in the Surveillance for Enteric Fever in Asia Project (SEAP) to assess incidence of enteric fever at 6 study hospitals in 3 countries. We recruited individuals presenting to the hospitals and obtained blood cultures to evaluate for enteric fever. For this analysis, we undertook cluster random household surveys in Dhaka, Bangladesh (2 sites); Karachi, Pakistan; Kathmandu, Nepal; and Kavrepalanchok, Nepal between January 2017 and February 2019, to ascertain care-seeking behavior for individuals with 1) fever for ≥3 consecutive days within the past 8 weeks; or 2) fever resulting in hospitalization within the past year. We also collected data about disease severity and household demographics and assets. We used mixed-effect multivariable logistic regression models to identify determinants of healthcare seeking at study hospitals and determinants of culture-confirmed enteric fever.Results: We enrolled 31 841 households (53 926 children) in Bangladesh, 25 510 households (84 196 children and adults) in Nepal, and 21 310 households (108 031 children and adults) in Pakistan. Children \u3c5 years were most likely to be taken to the study hospitals for febrile illness at all sites. Household wealth was positively correlated with healthcare seeking in 4 of 5 study sites, and at least one marker of disease severity was positively associated with healthcare seeking in 3 of 5 catchment areas. Wealth and disease severity were variably predictive of blood culture-confirmed enteric fever.Conclusions: Age, household wealth, and disease severity are important determinants of healthcare seeking for acute febrile illness and enteric fever risk in these communities, and should be incorporated into estimation models for enteric fever incidence