Efficient and optimal designs for correlated observations.

This thesis considers some aspects of the problem of finding efficient and optimal designs when observations are correlated. The two main areas that are examined are nested row-column (NRC) designs and early generation variety trials (EGVTs). In NRC designs, the experimental area is divided into b blocks, and each block is divided into P1 rows and P2 columns (blocks of size P1 x P2). Here, optimal NRC designs, which can be constructed from semi-balanced arrays, are obtained under the assumption that within-block observations are correlated. For a stationary reflection symmetric dependence structure, optimal NRC designs with blocks of size 2 x 2 are obtained for models with fixed block effects, which may also include row and/or column effects. It is shown that the efficiency of binary designs can be very low for some correlation values. Also, optimal NRC designs for blocks of size 3 x 3 and P1 x 2 (P1 ≥ 3 ) are determined. The optimality region for blocks of size P1 x P2 (P1 P2 ≥ 2) under the AR( 1)* AR( 1) process is also specified. It is shown that optimal NRC designs are highly specific to the correlation values. The purpose of EGVTs is to select top performing new crop varieties for further testing. Recently there has been much interest in the spatial analysis of EGVTs, but there has been little work on the design of efficient EGVTs when a spatial analysis is intended. Several intuitively simple criteria to assess the efficiency of designs for EGVTs are examined, and simulation studies suggest that some of these criteria are well associated with probabilities of selecting the highest yielding new varieties. Also, the efficiency and robustness of some systematic designs for EGVTs is investigated over several models and dependence structures. For the examples considered, it is shown that designs in which the plots containing control varieties are at least a knight's move apart are robust

Enhanced photocatalytic and disinfection activities of silver loaded ordered mesoporous titanium dioxide for water treatment

In the present paper ordered mesoporous titanium dioxide (TiO2) has been synthesized by using the nanocasting method with SBA-15 as a hard template and titanium alkoxide as the precursor. The silver has been loaded onto the obtained ordered mesoporous TiO2 using photoreduction method. The physicochemical properties of as-prepared and calcined silver loaded mesoporous titanium dioxide (SMTO) have been characterized by various techniques. The XRD pattern confirms the existence of tetragonal anatase-rutile mixed phases of TiO2 with a crystallite size of the range of 12-15 nm. SEM and TEM images show that the aggregation of nanocrystalline phase results in the formation of nanometer sized mesoporous TiO2 with a well-defined spherical morphology and retained ordered structure. The as-obtained samples exhibit good photocatalytic degradation of rhodamine B, Congo red and methyl orange dyes as model water contaminant at room temperature with UV light irradiation. The samples under study also show substantial disinfection properties against E. coli & S. aureus used as a model strain. The significant enhancement of the photocatalytic and disinfection activities of the SMTO materials is mainly attributed to their absorbed more photons and reduced electron-hole pair recombination due to synergic effect of porosity of the ordered structure and Ag-impregnated nanoparticles, respectively

Intention to use and Adoption of IT Innovations in Organizations: A Meta-Analytic Examination of the Moderating Role of Innovation Type and Socio-Economic Context

Present paper conducts a meta-analysis of the innovation features that influence the intention to use and adoption of information technology (IT) innovation in the organizations. Previous studies that assessed the influence of innovation features on intention to use and adoption have found inconsistent results and thus created confusion among academicians and practitioners. Present study consolidates the findings of previous studies using meta-analysis to reveal the key factors behind organizations’ intention to use and adoption of IT innovations. The study takes a step further by also determining the moderating role of innovation type (product vs. service innovations) and socio-economic context (developing vs. developed countries) on the relationships of innovation features with intention to use and adoption of IT innovations. It also provides multiple insightful theoretical and practical implications

Pursuing Digital Learning Platform Success: A Meta-Analytic Investigation of User and Cultural Contingencies

Digital learning platforms (DLPs) have emerged as highly effective tools to meet contemporary organizations’ learning and knowledge-creation needs. Advanced information and communication technologies (ICT) embedded in these platforms create mobile learning workspaces that deliver ubiquitous yet targeted learning experiences. Scholars have shown a keen interest in assessing the success of DLPs, but most studies have examined only a specific aspect of DLP success. Current findings also show inconsistencies and contradictions that confound our understanding of this important topic. As a result, an integrated and accurate understanding of DLP success is missing. In this paper, we adopt rigorous meta-analytic procedures to consolidate extant findings and reconcile inconsistencies in our understanding of DLP success. Additionally, we extend our meta-analyses to investigate the contingency effects of two moderating variables—user context and cultural context. The results provide a more comprehensive and accurate understanding of DLP success. Our study contributes to the literature by extending the theory on DLPs and information systems (IS) success and by providing insightful recommendations for practitioners

Jaundice in adult patients above 50 years of age: a comparative study of liver function tests

Background: Diagnosis of jaundice involves a range of tests. The liver function tests are done in all to arrive at a diagnosis and then manage the case appropriately. With advancing age, the incidence of liver disease increases. Understanding these changes is important for the management of liver diseases in the elderly. We conducted this study to find the difference in mean levels of Liver enzymes in younger and older age group of patients suffering with jaundice.Methods: It was a prospective observational study. All patients admitted with jaundice in the medicine ward satisfying inclusion/exclusion criteria were enrolled. The results of liver function tests in younger age and older age participants were then compared.Results: Total 100 participants were enrolled during the study period. 53 were enrolled in group one and the rest in group two. Anorexia (90%) was the most common symptom followed by abdominal distension (54%). The total bilirubin (8.8±4.7) as well as conjugated bilirubin (3.4±2.8) were higher in group one though they were not significant statistically (p=0.10 and 0.25 respectively). Mean AST and ALT levels were much higher in group 1 and statistically significant (p values <0.004 and 0.002 respectively). Conversely the mean PT values were higher in group two (p=0.02).Conclusions: Although the symptom severity may be more in elderly, the LFTs are not deranged proportionately. So there is a need to devise separate cut offs and these have to be lower for the older age group patients with jaundice. More studies with larger sample size are required to confirm the results

Common Variants of Homocysteine Metabolism Pathway Genes and Risk of Type 2 Diabetes and Related Traits in Indians

Hyperhomocysteinemia, a risk factor for cardiovascular disorder, obesity, and type 2 diabetes, is prevalent among Indians who are at high risk of these metabolic disorders. We evaluated association of common variants of genes involved in homocysteine metabolism or its levels with type 2 diabetes, obesity, and related traits in North Indians. We genotyped 90 variants in initial phase (2.115 subjects) and replicated top signals in an independent sample set (2.085 subjects). The variant MTHFR-rs1801133 was the top signal for association with type 2 diabetes (OR = 0.78 (95%  CI = 0.67–0.92), P = 0.003) and was also associated with 2 h postload plasma glucose (P = 0.04), high-density lipoprotein cholesterol (P = 0.004), and total cholesterol (P = 0.01) in control subjects. These associations were neither replicated nor significant after meta-analysis. Studies involving a larger study population and different ethnic groups are required before ruling out the role of these important candidate genes in type 2 diabetes, obesity, and related traits

Common variants of FTO are associated with childhood obesity in a cross-sectional study of 3,126 urban Indian children

Background: FTO variants are robustly associated with obesity and related traits in many population and shown to have variable impact during life course. Although studies have shown association of FTO variants with adiposity in adult Indian, its association in Indian children is yet to be confirmed. Methods: Here we examined association of FTO variants (rs9939609 and rs8050136) with obesity and related anthropometric and biochemical traits in 3,126 Indian children (aged 11–17 years) including 2,230 normal-weight and 896 over-weight/obese children. We also compared effects observed in the present study with that observed in previous studies on South Asian adults and children of other ethnic groups. Results: The variant rs9939609 showed significant association with risk of obesity [OR = 1.21, P = 2.5×10−3] and its measures BMI, weight, waist circumference and hip circumference [β range = 0.11 to 0.14 Z-score units; P range = 1.3×10−4 to 1.6×10−7] in children. The observed effect sizes in Indian children were similar to those reported for European children. Variant rs9939609 explained 0.88% of BMI variance in Indian children. The effect sizes of rs9939609 on BMI and WC were ∼2 fold higher in children than adults. Interestingly rs9939609 was also associated with serum levels of thyroid stimulating hormone (TSH) [β = 0.10 Z-score, P = 5.8×10−3]. The other variant rs8050136 was in strong linkage disequilibrium with rs9939609 (r2 = 0.97) and provided similar association results. Conclusion: The study provides first report of association of FTO variants with obesity and related anthropometric traits in Indian children with higher impact in children compared to adults. We also demonstrated association of FTO variant with serum levels of TSH, indicating putative influence of FTO in hypothalamic-pituitary-thyroid axis

Investigation of the Mechanical Properties of Glass Fiber – Chicken Feather Hybrid Composite

The production and/or worldwide consumption of chicken at an industrial or domestic level lead to a considerable quantity of chicken feather residue as a waste by-product. Chicken feathers have a possible application in preparing lightweight composites. The use of chicken feathers as a constituent to prepare hybrid composites leads to a solution for disposal of the feathers. In this study, chicken feathers were used as filler material to prepare hybrid composites. Different varieties of composites were prepared by a chicken feather hand-layup technique, and by varying the percentage weight of the chicken feathers. Specimens were prepared and tested according to ASTM standards. The 10 wt. % chicken feather-filled hybrid composites indicated the maximum tensile strength (193 MPa), flexural strength (148 MPa) and impact strength (3.65 Joules). Scanning Electron Microscopy (SEM) analysis was carried out to find the fracture and interfacial characteristics of the composites. The results indicated that, these composites can be used in domestic, automobile and structural applications which carry nominal loads