Malnutrition among adolescents is often associated with inadequate dietary diversity (DD). We aimed to explore the prevalence of inadequate DD and its socio-economic determinants among adolescent girls and boys in Bangladesh. A cross-sectional survey was conducted during the 2018–19 round of national nutrition surveillance in Bangladesh. Univariate and multivariable logistic regression was performed to identify the determinants of inadequate DD among adolescent girls and boys separately. This population-based survey covered eighty-two rural, non-slum urban and slum clusters from all divisions of Bangladesh. A total of 4865 adolescent girls and 4907 adolescent boys were interviewed. The overall prevalence of inadequate DD was higher among girls (55⋅4 %) than the boys (50⋅6 %). Moreover, compared to boys, the prevalence of inadequate DD was higher among the girls for almost all socio-economic categories. Poor educational attainment, poor maternal education, female-headed household, household food insecurity and poor household wealth were associated with increased chances of having inadequate DD in both sexes. In conclusion, more than half of the Bangladeshi adolescent girls and boys consumed an inadequately diversified diet. The socio-economic determinants of inadequate DD should be addressed through context-specific multisectoral interventions.

The World Health Organization set a target of a 15% relative reduction in the prevalence of insufficient physical activity (IPA) by 2025 among adolescents and adults globally. In Bangladesh, there are no national estimates of the prevalence of IPA among adolescents. The aim of this study was to estimate the prevalence of and risk factors associated with IPA among adolescent girls and boys. Data for 4865 adolescent girls and 4907 adolescent boys, collected as a part of a National Nutrition Surveillance in 2018–19, were analysed for this study. A modified version of the Global Physical Activity Questionnaire (GPAQ) was used to collect physical activity data. The World Health Organization recommended cut-off points were used to estimate the prevalence of IPA. Bivariate and multivariable logistic regression was performed to identify factors associated with IPA. Prevalences of IPA among adolescent girls and boys were 50.3% and 29.0%, respectively, and the prevalence was significantly higher among early adolescents (10–14 years) than late adolescents (15–19 years) among both boys and girls. The IPA prevalence was highest among adolescents living in non-slum urban areas (girls: 77.7%; boys: 64.1%). For both boys and girls, younger age, non-slum urban residence, higher paternal education and increased television viewing time were significantly associated with IPA. Additionally, residing in slums was significantly associated with IPA only among the boys. Higher maternal education was associated with IPA only among the girls. This study identified several modifiable risk factors associated with IPA among adolescent boys and girls in Bangladesh. These factors should be addressed through comprehensive public health interventions to promote physical activity among adolescent girls and boys.

Parthenium hysterophorus is a prolific invasive weed species, which infests many crops in over 40 countries around the world. A 2-year field study was carried out to quantify the potential impacts of this weed on direct-seeded rice. Parthenium weed was allowed to compete for 2, 4, 6 or 8 weeks after crop emergence, while full season weedy and weed-free plots were maintained as controls. Parthenium weed plants grew taller and attained more biomass as the competition duration prolonged. The yield and yield-related attributes of rice were negatively affected with increasing competition duration. The season-long competition caused the highest reductions in panicle number (28–34%), panicle length (26–27%), grains per panicle (22–23%) and grain yield (33 and 38%) of rice in both years. Weed competition for 2–8 weeks caused 5–34% and 6–33% losses in rice grain yield during both years, respectively. Importantly, Parthenium weed control after 8 weeks of competition did not improve rice yield significantly. The results suggested that Parthenium weed should be controlled in rice fields between 4 and 8 weeks after crop emergence under direct-seeded conditions to avoid over 10% yield losses.

Manganese (Mn) is one important microelement for plants and the human beings. This study was conducted to evaluate the potential of Mn nutrition in improving the productivity and grain biofortification of wheat. For optimization of Mn seed treatments, seeds were primed with 0.1 and 0.01 M Mn solution, or were coated with 250 and 500 mg Mn kg−1 seed. The optimized treatments were used in the second experiment replicated over time and space. In the first experiment conducted at Faisalabad during 2012–2013, maximum grain yield was recorded with Mn seed priming (0.1 M Mn solution), while maximum grain Mn concentration was recorded with foliar application of 0.75 M Mn solution and seed coating with 250 mg Mn kg−1 seed. In the second experiment, conducted at Faisalabad and Sheikhupura during 2013–2014, and at Faisalabad during 2014–2015, maximum grain yield and grain Mn concentration were recorded from seed priming with 0.1 M Mn solution. Regardless of method, Mn application improved the productivity and grain biofortification of wheat. Overall order of improvement in grain yield was seed priming (3.87 Mg ha−1) > foliar application (3.74 Mg ha−1) > seed coating (3.57 Mg ha−1). Regarding grain Mn concentration, the best treatment was seed priming (41.40 µg g−1) followed by seed coating (39.87 µg g−1) and foliar application (36.94 µg g−1). Maximum net returns and benefit-cost ratio were obtained with Mn seed priming, while maximum marginal rate of return was obtained with Mn seed coating. In conclusion, Mn application through seed treatments was cost effective for improving the productivity and grain biofortification of bread wheat in alkaline calcareous soil.

In this paper we propose a new nonparametric test for conditional heteroskedasticity based on a measure of nonparametric goodness-of-fit (R2) that is obtained from the local polynomial regression of the residuals from a parametric regression on some covariates. We show that after being appropriately standardized, the nonparametric R2 is asymptotically normally distributed under the null hypothesis and a sequence of Pitman local alternatives. We also prove the consistency of the test and propose a bootstrap method to obtain the bootstrap p-values. We conduct a small set of simulations and compare our test with some popular parametric and nonparametric tests in the literature.

In this paper we develop nonparametric estimators of the joint time series data generating process (DGP) of (xt, yt) at different t-values, of conditional DGP, of the conditional mean of xt given the past values of x and y, and, more generally, the conditional mean of (xt, yt) given their past values (vector autoregression). We establish, among other results, the central limit theorems for these estimators under far weaker mixing conditions than those used in Robinson [23], where only the xt series is considered. Uniform consistency and rate results for the consistencies of various estimators are also obtained. The results of the paper are useful in light of the fact that often the functional form of the dynamic regression is not known and also the assumption of the Gaussian process is not true.

Fe-doped SrRuO3 thin films were grown on SrTiO3 (STO) substrates by using the Pulse Laser Deposition (PLD) method. Fe concentrations in the SrRuO3 thin films ranged from 0 % to 11 % to manifest the effect of Fe doping on their microstructure. Lattice constants of the films did not show obvious changes with the Fe doping whereas surface morphologies drastically changed from stepped to island structure with increasing Fe. X-ray reflectivity revealed that the surface and interfacial roughness decreased with increasing concentration of Fe. Surface roughness of the films was confirmed by atomic force microscopy. Therefore, a precise determination of film roughness as well as its growth mechanism using X-ray and AFM is exploited to correlate the Fe doping with structural disorder.

We define a three-step procedure for more efficient estimation of the nonparametric regression mean with nonparametric autocorrelated errors. The procedure is based upon a nonparametric prewhitening transformation of the dependent variable that has to be estimated from the data by a local polynomial technique. We establish the asymptotic distribution of our estimator under weak dependence conditions and show that it is more efficient than the conventional local polynomial estimator. Furthermore, we consider criterion functions based on the linear exponential family, which include the local polynomial least squares criterion as a special case. Simulation evidence suggests that significant gains can be achieved in finite samples with our approach.The authors thank Oliver Linton for his many constructive and helpful suggestions. The very insightful comments from the referees are also gratefully acknowledged. The second author gratefully acknowledges financial support from the Academic Senate, UCR.