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The photoelectric effects on the instability of the current-driven dust ion-acoustic (DIA) waves in a collisional and streaming dusty plasmas are theoretically investigated using fluid model with dust charge fluctuation considering dust grains as negatively charged. It is found that the photoelectric effects through dust charge fluctuation give the growth of the DIA waves beside the damping effects of collision and streaming of the plasma species. Growth rate of the DIA waves are numerically investigated using the values of appropriate plasma parameters.

Field experiment on sowing dates was carried out with BARI Mung-6 during pre-monsoon (kharif-I) season of 2021 for the evaluation of Agricultural Production Systems Simulator (APSIM) crop model. The APSIM model was parameterized using data from March 10 sowing, while validation was done with other sowing dates and data from literatures. Simulation was done with elevated temperatures (1-, 2- and 3-°C) to find out the adaptation option against future temperature stress situations. The model was run for different sowing dates using long-term (1981–2021) historical weather data. The evaluations showed that the model performance was satisfactory in predicting crop phenology, total biomass and grain yields of BARI Mung-6. Simulated grain yields during March 10 to March 25 sowings were very similar to attainable grain yields while, very early or late sowing gave comparatively lower grain yields. The best simulated planting window was from 15 to 25 March having the highest mean grain yields with less variability over the years. Increase in temperature by 1°C increase exhibited no significant influence on grain yields across the sowing dates, but significant yield reductions were observed with the rise of temperatures by 2 and 3°C on March 20, March 30 and April 10 sowings. Elevated temperatures showed positive impact on grain yield of March 10 sowing only. Results revealed that optimum sowing window for mungbean is from 15 to 25 March with existing weather conditions. In future temperature rises situations, sowing of seeds by the first week of March would be one of the options to combat climate change impact on mungbean grain yield in Bangladesh.

This thesis deals with weighted (generalised) least squares estimation and analysis for some common experimental designs with the error variance heteroscedastic with respect to the levels of one factor, namely, the treatments or (for split-plot designs) sub-plot treatments. The simple regression model with error variance heteroscedastic with respect to the values of the independent variable, is also considered briefly. The observations in any of the analyses considered are grouped in such a way that the error variance is constant within groups but varies from group to group.On the assumption that the group variances are known, the weighted least squares estimators of the linear parameters and the corresponding analysis (Aitken, 1934-35; Plackett, I960, pp. 47-49) are provided for each design or model. An expression for joint confidence intervals of parametric contrasts for the heteroscedastic models is also obtained. The estimators of the linear parameters and other statistics usually involve actual weights, the reciprocals of the group variances.The actual weights are not usually known. The estimators of the group variances are therefore derived for each design or model. for some designs, the minimum norm quadratic unbiased estimators (Rao, 1970; 1973, pp. 303-305) of group variances are independently distributed as multiples of x2. For other designs, almost unbiased estimators (Horn et al., 1975) of group variances have negligible bias and are approximately independently distri-buted as multiples of x2 Reciprocals of these estimators are used as the estimated weights.The weighted least squares estimators of the linear parameters or variance components and other statistics including test-statistics using estimated weights, are generally biased. It is shown in the thesis how a major part of the bias can be removed; the procedure stems from a theorem due to Meier (1953). The estimators and other statistics using estimated weights are adjusted accordingly. A modified form of this theorem is also proved for correlated estimators of the group variances. A small Monte Carlo study conducted for completely randomised designs showed that the performances of the adjusted statistics are more or less satisfactory.The designs and models covered in this thesis are: completely randomised designs, the general two-way model with proportional cell frequencies, general block designs, randomised complete block designs, latin square designs, split-plot designs with two treatment factors and the linear regression model. For the first three designs, both the fixed-effects models and random or mixed models are considered whereas only the fixed-effects models are dealt with for the remaining three designs.

For factorial designs with unequal cell variances, weighted least squares estimators of the parameters of the model are obtained with the help of a condition that the cell frequencies are proportional to the corresponding cell variances. This proportionality condition also produces balance of the design so that the expectations of mean squares can be obtained and tests of significance performed easily. When cell variances are not known, the sample for each cell is drawn in two stages. The cell samples at the first stage provide independent estimators of cell variances. The size of the final sample in each cell is then determined by the proportionality condition using estimated variances. The same analysis is then carried out for final sample along with some adjustment for bias wherever necessary. The method is applicable to nested and other designs. /// Pour ce qui concerne le design factoriel avec d'inegales variances de cellules les estimations des paramètres du modèle à l'aide des moindres carrés ne sont, obtenues que si la fréquence correspond aux variances de cellules. Cette condition de proportionnalité réalise aussi l'équilibre du design ainsi il est possible d'obtenir les moyens carrés prévus et de tester aisément et efficacement la signification statistique. Lorsque les variances des cellules ne sont pas connues les échantillons sont pris de chaque cellule sur deux fois ceux de la première prise prouvent que les estimations des cellules sont indépendantes le volume de l'échantillon final est déterminé par la condition de proportionnalité appliquée dans les variances estimées. La même analyse est valable pour l'échantillon final avec quelques ajustements en cas de nécessité. La méthode est appliqueé dans les design intégrés et autres.

For row-and-column designs, it is assumed that the error variance is constant for observations for one treatment but varies from treatment to treatment. Assuming group variances to be known, estimators of the linear parameters are obtained by weighted (generalised) least squares method and the corresponding analysis is given. Canonical forms of the treatment and error sums of squares are provided under a certain condition. For unknown group variances, an adjustment of the statistics using estimated weights is proposed for removing much of the resulting bias.

For general block designs (with unequal block sizes), the error variance is assumed to be heteroscedastic with respect to the levels of treatments. For known error variances, the weighted (generalised) least squares estimators of the treatment parameters are obtained and the corresponding analysis is provided. Canonical forms of the two sums of squares concerned are also given. When group variances are not known, an adjustment of the treatment estimators and other statistics using estimated weights is suggested for removing much of the resulting bias. The adjustment stems from a theorem due to Meier (1953).

This paper provides an iterative method for the analysis of experimental designs with several non-orthogonal and non-interacting classifications. The method is based on the recursive relationships given by Rees (1966), and generalises the iterative procedure of Caliński (1971) for obtaining the covariance matrix of the adjusted treatment means for designs with only two classifications, namely blocks and treatments. The present paper also generalises the canonical forms obtained by Pearce and Jeffers (1971) for the adjusted treatments sum of squares and the error sum of squares.

Up to half of neonatal deaths in high mortality settings are due to infections, many of which can originate through the freshly cut umbilical cord stump. We aimed to assess the effectiveness of two cord-cleansing regimens with the promotion of dry cord care in the prevention of neonatal mortality. We did a community-based, parallel cluster-randomised trial in Sylhet, Bangladesh. We divided the study area into 133 clusters, which were randomly assigned to one of the two chlorhexidine cleansing regimens (single cleansing as soon as possible after birth; daily cleansing for 7 days after birth) or promotion of dry cord care. Randomisation was done by use of a computer-generated sequence, stratified by cluster-specific participation in a previous trial. All livebirths were eligible; those visited within 7 days by a local female village health worker trained to deliver the cord care intervention were enrolled. We did not mask study workers and participants to the study interventions. Our primary outcome was neonatal mortality (within 28 days of birth) per 1000 livebirths, which we analysed on an intention-to-treat basis. This trial is registered with ClinicalTrials.gov, number NCT00434408. Between June, 2007, and September, 2009, we enrolled 29 760 newborn babies (10 329, 9423, and 10 008 in the multiple-cleansing, single-cleansing, and dry cord care groups, respectively). Neonatal mortality was lower in the single-cleansing group (22·5 per 1000 livebirths) than it was in the dry cord care group (28·3 per 1000 livebirths; relative risk [RR] 0·80 [95% CI] 0·65–0·98). Neonatal mortality in the multiple-cleansing group (26·6 per 1000 livebirths) was not statistically significantly lower than it was in the dry cord care group (RR 0·94 [0·78–1·14]). Compared with the dry cord care group, we recorded a statistically significant reduction in the occurrence of severe cord infection (redness with pus) in the multiple-cleansing group (risk per 1000 livebirths=4·2 vs risk per 1000 livebirths=1·2; RR 0·35 [0·15–0·81]) but not in the single-cleansing group (risk per 1000 livebirths=3·3; RR 0·77 [0·40–1·48]). Chlorhexidine cleansing of a neonate's umbilical cord can save lives, but further studies are needed to establish the best frequency with which to deliver the intervention. United States Agency for International Development and Save the Children's Saving Newborn Lives program, through a grant from the Bill & Melinda Gates Foundation.

Shigellosis, caused by Shigella species, is a major public health problem in Bangladesh. To determine the prevalence and distribution of different Shigella species, we analyzed 10,827 Shigella isolates from patients between 2001 and 2011. S. flexneri was the predominant species isolated throughout the period. However, the prevalence of S. flexneri decreased from 65.7% in 2001 to 47% in 2011, whereas the prevalence of S. sonnei increased from 7.2% in 2001 to 25% in 2011. S. boydii and S. dysenteriae accounted for 17.3% and 7.7% of the isolates respectively throughout the period. Of 200 randomly selected S. sonnei isolates for extensive characterization, biotype g strains were predominant (95%) followed by biotype a (5%). Resistance to commonly used antibiotics including trimethoprim-sulfamethoxazole, nalidixic acid, ciprofloxacin, mecillinam and ampicillin was 89.5%, 86.5%, 17%, 10.5%, and 9.5%, respectively. All isolates were susceptible to ceftriaxone, cefotaxime, ceftazidime and imipenem. Ninety-eight percent of the strains had integrons belonging to class 1, 2 or both. The class 1 integron contained only dfrA5 gene, whereas among class 2 integron, 16% contained dhfrAI-sat1-aadA1-orfX gene cassettes and 84% harbored dhfrA1-sat2 gene cassettes. Plasmids of ∼5, ∼1.8 and ∼1.4 MDa in size were found in 92% of the strains, whereas only 33% of the strains carried the 120 MDa plasmid. PFGE analysis showed that strains having different integron patterns belonged to different clusters. These results show a changing trend in the prevalence of Shigella species with the emergence of multidrug resistant S. sonnei. Although S. flexneri continues to be the predominant species albeit with reduced prevalence, S. sonnei has emerged as the second most prevalent species replacing the earlier dominance by S. boydii and S. dysenteriae in Bangladesh.

T-cell-based immunotherapies are promising treatments for cancer patients. Although durable responses can be achieved in some patients, many patients fail to respond to these therapies, underscoring the need for improvement with combination therapies. From a screen of 850 bioactive compounds, we identify HSP90 inhibitors as candidates for combination with immunotherapy. We show that inhibition of HSP90 with ganetespib enhances T-cell-mediated killing of patient-derived human melanoma cells by their autologous T cells in vitro and potentiates responses to anti-CTLA4 and anti-PD1 therapy in vivo. Mechanistic studies reveal that HSP90 inhibition results in upregulation of interferon response genes, which are essential for the enhanced killing of ganetespib treated melanoma cells by T cells. Taken together, these findings provide evidence that HSP90 inhibition can potentiate T-cell-mediated anti-tumor immune responses, and rationale to explore the combination of immunotherapy and HSP90 inhibitors. Many patients fail to respond to T cell based immunotherapies. Here, the authors, through a high-throughput screening, identify HSP90 inhibitors as a class of preferred drugs for treatment combination with immunotherapy.