Emerging vistas of Remote Sensing Tools in Pollination Studies

With the growth of information and technology across the globe, remote sensing applications find a place in the ecological studies of pollinators. The utilization of remote sensing tools in understanding the ecosystem services rendered by the bee pollinators is reviewed here. We discussed how radar and radio telemetry techniques helps to track individual bees, their foraging behaviour and density in relation to altered phenology of flowering crops in a landscape. Role of satellite imagery tools in studying characterizing a landscape affected by anthropogenic factors was discussed.  Monitoring invasive bee species that cause a threat to native bee fauna was explored. We explained the utilization of unmanned aerial vehicles to map the floral resource that influence the density and incidence of pollinators. Remote sensing tools used to measure sequence of pollination events was discussed

Pressure screening in the interior of primary shells in double-wall carbon nanotubes

The pressure response of double-wall carbon nanotubes has been investigated by means of Raman spectroscopy up to 10 GPa. The intensity of the radial breathing modes of the outer tubes decreases rapidly but remain observable up to 9 GPa, exhibiting a behavior similar (but less pronounced) to that of single-wall carbon nanotubes, which undergo a shape distortion at higher pressures. In addition, the tangential band of the external tubes broadens and decreases in amplitude. The corresponding Raman features of the internal tubes appear to be considerably less sensitive to pressure. All findings lead to the conclusion that the outer tubes act as a protection shield for the inner tubes whereas the latter increase the structural stability of the outer tubes upon pressure application.Comment: PDF with 15 pages, 3 figures, 1 table; submitted to Physical Review

Developing targeted client communication messages to pregnant women in Bangladesh: a qualitative study

AbstractBackground:Timely and appropriate evidence-based practices during antenatal care improve maternal andneonatal health. There is a lack of information on how pregnant women and families perceive antenatal care inBangladesh. The aim of our study was to develop targeted client communication via text messages for increasingantenatal care utilization, as part of an implementation of an electronic registry for maternal and child health.Methods:Using a phenomenological approach, we conducted this qualitative study from May to June 2017 in two sub-districts of Chandpur district, Bangladesh. We selected study participants by purposive sampling. A total of 24 in-depthinterviews were conductedwithpregnantwomen(n= 10), lactating women (n=5),husbands(n= 5), and mothers-in-law(n= 4). The Health Belief Model (HBM) was used to guide the datacollection. Thematic analysis was carried out manuallyaccording to the HBM constructs. We used behavior change techniques to inform the development of targeted clientcommunication based on the thematic results.Results:Almost no respondents mentioned antenatal care as a preventive form of care, and only perceived it as necessary ifany complications developed during pregnancy. Knowledge of the content of antenatal care (ANC) and pregnancycomplications was low. Women reported avariety of reasons for not attending ANC, including the lack of information onthe timing of ANC; lack of decision-making power; long-distance to access care; being busy with household chores, and notbeing satisfied with the treatment by health care providers. Study participants recommended phone calls as their preferredcommunication strategy when asked to choose between thephone call and text message, but saw text messages as afeasible option. Based on the findings, we developed a library of 43 automatically customizable text messages to increaseANC utilization.Conclusions:Pregnant women and family members had limited knowledge about antenatal care and pregnancycomplications. Effective health information through text messages could increase awareness of antenatal careamong the pregnant women in Bangladesh. This study presents an example of designing targeted clientcommunication to increase antenatal care utilization within formal scientific frameworks, including a taxonomy ofbehavior change techniques.publishedVersio

Pressure-Induced Interlinking of Carbon Nanotubes

We predict new forms of carbon consisting of one and two dimensional networks of interlinked single wall carbon nanotubes, some of which are energetically more stable than van der Waals packing of the nanotubes on a hexagonal lattice. These interlinked nanotubes are further transformed with higher applied external pressures to more dense and complicated stable structures, in which curvature-induced carbon sp$^{3}$ re-hybridizations are formed. We also discuss the energetics of the bond formation between nanotubes and the electronic properties of these predicted novel structures.Comment: 4 pages, 4 postscript figures; To be appear in PR

van der Waals interaction in nanotube bundles : consequences on vibrational modes

We have developed a pair-potential approach for the evaluation of van der Waals interaction between carbon nanotubes in bundles. Starting from a continuum model, we show that the intertube modes range from $5 cm^{-1}$ to $60 cm^{-1}$. Using a non-orthogonal tight-binding approximation for describing the covalent intra-tube bonding in addition, we confirme a slight chiral dependance of the breathing mode frequency and we found that this breathing mode frequency increase by $\sim$ 10 % if the nanotube lie inside a bundle as compared to the isolated tube.Comment: 5 pages, 2 figure

The Computational Complexity of Generating Random Fractals

In this paper we examine a number of models that generate random fractals. The models are studied using the tools of computational complexity theory from the perspective of parallel computation. Diffusion limited aggregation and several widely used algorithms for equilibrating the Ising model are shown to be highly sequential; it is unlikely they can be simulated efficiently in parallel. This is in contrast to Mandelbrot percolation that can be simulated in constant parallel time. Our research helps shed light on the intrinsic complexity of these models relative to each other and to different growth processes that have been recently studied using complexity theory. In addition, the results may serve as a guide to simulation physics.Comment: 28 pages, LATEX, 8 Postscript figures available from [email protected]

An Electronic Registry for Improving the Quality of Antenatal Care in Rural Bangladesh (eRegMat): Protocol for a Cluster Randomized Controlled Trial

Background: Digital health interventions (DHIs) can alleviate several barriers to achieving better maternal and child health. The World Health Organization’s guideline recommendations for DHIs emphasize the need to integrate multiple DHIs for maximizing impact. The complex health system of Bangladesh provides a unique setting for evaluating and understanding the role of an electronic registry (eRegistry) for antenatal care, with multiple integrated DHIs for strengthening the health system as well as improving the quality and utilization of the public health care system. Objective: The aim of this study is to assess the effect of an eRegistry with DHIs compared with a simple digital data entry tool without DHIs in the community and frontline health facilities. Methods: The eRegMat is a cluster-randomized controlled trial conducted in the Matlab North and Matlab South subdistricts in the Chandpur district, Bangladesh, where health facilities are currently using the eRegistry for digital tracking of the health status of pregnant women longitudinally. The intervention arm received 3 superimposed data-driven DHIs: health worker clinical decision support, health worker feedback dashboards with action items, and targeted client communication to pregnant women. The primary outcomes are appropriate screening as well as management of hypertension during pregnancy and timely antenatal care attendance. The secondary outcomes include morbidity and mortality in the perinatal period as well as timely first antenatal care visit; successful referrals for anemia, diabetes, or hypertension during pregnancy; and facility delivery. Results: The eRegistry and DHIs were co-designed with end users between 2016 and 2018. The eRegistry was implemented in the study area in July 2018. Recruitment for the trial started in October 2018 and ended in June 2020, followed by an 8-month follow-up period to capture outcome data until February 2021. Trial results will be available for publication in June 2021. Conclusions: This trial allows the simultaneous assessment of multiple integrated DHIs for strengthening the health system and aims to provide evidence for its implementation. The study design and outcomes are geared toward informing the living review process of the guidelines for implementing DHIs.publishedVersio

Enhancement of Friction between Carbon Nanotubes: An Efficient Strategy to Strengthen Fibers

Interfacial friction plays a crucial role in the mechanical properties of carbon nanotube based fibers, composites, and devices. Here we use molecular dynamics simulation to investigate the pressure effect on the friction within carbon nanotube bundles. It reveals that the intertube frictional force can be increased by a factor of 1.5 ~ 4, depending on tube chirality and radius, when all tubes collapse above a critical pressure and when the bundle remains collapsed with unloading down to atmospheric pressure. Furthermore, the overall cross-sectional area also decreases significantly for the collapsed structure, making the bundle stronger. Our study suggests a new and efficient way to reinforce nanotube fibers, possibly stronger than carbon fibers, for usage at ambient conditions.Comment: revtex, 5 pages, accepted by ACS Nano 10 Dec 200

eRegMat – a digital registry for improved quality of antenatal care: a cluster-randomized trial in a rural area in Bangladesh

Introduction Longitudinal client tracking systems with digital health interventions are recommended for implementation in resource-limited settings but lack evidence of benefits, harms, and implementation. In the eRegMat cluster-randomized controlled trial, we aimed to assess the effectiveness of an eRegistry versus an unshared digital client record. Methods Fifty-nine primary health care facilities in Matlab, Bangladesh were randomized with a 1:1 allocation ratio to receive an eRegistry (intervention, 30 health facilities) with decision support, feedback dashboards and targeted client communication, or an unshared digital client record without digital health interventions (control, 29 health facilities). We assessed timely antenatal care attendance, quality of care, and health outcomes. Outcome data were captured in the eRegistry, or unshared digital client record used by health workers, and through a postpartum household survey. We estimated adjusted relative risks (ARRs) following the intention-to-treat principle and adjusted for cluster randomization. Results From October 2018 to June 2020, 3023 pregnant women were enrolled in the intervention and 2746 in the control groups through community and facility registrations. Intervention and control groups did not differ for the primary outcomes: timely attendance at eligible antenatal care visits (42.5% vs. 40.3%, ARR 0.96, 95% CI 0.89–1.05, p-value 0.4) and hypertension screening and management (95.1% vs. 94.7%, ARR 1.00, 95% CI 0.96–1.03, p-value 0.8). The secondary outcome of perinatal mortality and severe perinatal morbidities was lower in the intervention (14.6%) compared to the control group (15%) (ARR 0.74, 95% CI 0.58–0.96, p-value 0.02), with the change mostly attributed to morbidity outcomes. Conclusion Due to technical and implementation challenges we were unable to estimate the effect of the intervention with sufficient precision. Challenges included delays in rollout of the digital health interventions and outcome data collection, existence of parallel documentation systems on paper and digital and the COVID-19 pandemic. Given these methodological constraints, we are unable to draw definitive interpretations of trial results.publishedVersio

Structural and dielectric properties of Sr2_{2}TiO4_{4} from first principles

We have investigated the structural and dielectric properties of Sr$_{2}$TiO$_{4}$,the first member of the Sr$_{n+1}$Ti$_{n}$O$_{3n+1}$ Ruddlesden-Popper series, within density functional theory. Motivated by recent work in which thin films of Sr$_{2}$TiO$_{4}$ were grown by molecular beam epitaxy (MBE) on SrTiO$_{3}$ substrates, the in-plane lattice parameter was fixed to the theoretically optimized lattice constant of cubic SrTiO$_{3}$ (n=$\infty$), while the out-of-plane lattice parameter and the internal structural parameters were relaxed. The fully relaxed structure was also investigated. Density functional perturbation theory was used to calculate the zone-center phonon frequencies, Born effective charges, and the electronic dielectric permittivity tensor. A detailed study of the contribution of individual infrared-active modes to the static dielectric permittivity tensor was performed. The calculated Raman and infrared phonon frequencies were found to be in agreement with experiment where available. Comparisons of the calculated static dielectric permittivity with experiments on both ceramic powders and epitaxial thin films are discussed.Comment: 11 pages, 1 figure, 8 tables, submitted to Phys. Rev.