Weakly Supervised Action Localization by Sparse Temporal Pooling Network

We propose a weakly supervised temporal action localization algorithm on untrimmed videos using convolutional neural networks. Our algorithm learns from video-level class labels and predicts temporal intervals of human actions with no requirement of temporal localization annotations. We design our network to identify a sparse subset of key segments associated with target actions in a video using an attention module and fuse the key segments through adaptive temporal pooling. Our loss function is comprised of two terms that minimize the video-level action classification error and enforce the sparsity of the segment selection. At inference time, we extract and score temporal proposals using temporal class activations and class-agnostic attentions to estimate the time intervals that correspond to target actions. The proposed algorithm attains state-of-the-art results on the THUMOS14 dataset and outstanding performance on ActivityNet1.3 even with its weak supervision.Comment: Accepted to CVPR 201

Submergence effects on jet behavior in scour by a plane wall jet

In this study, the effects of submergence on local scour in a uniform cohesionless sediment bed by a plane turbulent wall jet and the resulting flow field were investigated experimentally. Here, submergence is defined as the ratio of the tailwater depth to the thickness of the jet at its origin. The main focus was to determine scour dimensions at an asymptotic state, examine whether there was similarity in the velocity profiles for the flow in the scour hole, and to determine the growth of the length scales and decay of the maximum velocity of the jet. Also examined were the relationships between the scales for the velocity field in the scour hole and the scour hole size.In the experiments, the range of submergence was varied from 3-17.5, whereas the range of densimetric Froude number and the ratio of the boundary roughness to the gate opening (relative boundary roughness) were varied from 4.4-6.9 and 0.085-0.137 respectively. The velocity field in the scour hole at asymptotic state was measured using a SonTek 16-MHz MicroADV. Time development of the characteristic dimensions of the scour hole was also measured.The dimensions of the scour hole were found to increase with increasing submergence for all experiments with a “bed-jet” flow regime. In the bed-jet flow regime, the jet remains near the bed throughout the scouring process. Further, the time development of the scour hole dimensions were observed to increase approximately linearly with the logarithm of time up to a certain time before the beginning of asymptotic state for experiments with either the bed-jet or surface-jet flow regimes. The flow field results showed that the velocity profiles in the region of forward flow and the recirculating region above the jet were similar in shape up to about the location of the maximum scour depth. Relationships describing this velocity profile, including its velocity and length scales, were formulated. The decay rate of the maximum velocity, the growth of the jet half-width, and the boundary layer thickness were also studied. The decay and the growth rate of the jet length scales were found to be influenced by the submergence ratio, densimetric Froude number, and the relative boundary roughness.Two distinct stages in the decay of the maximum streamwise velocity, with distance along the direction of flow, were observed for the jet flows having a bed-jet flow regime. The first stage of velocity decay was characterized by a curvilinear decay of velocity, which followed that of a wall jet on a smooth, rigid bed for streamwise distance approximately equal to 2L. For the surface-jet flow regime, the decay of velocity was observed to be similar to that of a free-jump on a smooth, rigid bed for a streamwise distance approximately equal to L. Here, L is defined as the streamwise distance measured from the end of the rigid apron to where the maximum streamwise velocity in the jet is half the velocity of the jet at the end of apron. The streamwise maximum velocity of the jet was then seen to increase in what was called the recovery zone.A relationship for the streamwise decay of the maximum velocity within the scour hole is proposed. Moreover, other scales representing the flow inside the scour hole such as the streamwise distance from the end of the apron to where the streamwise maximum velocity starts to deviate from curvilinear to linear decay and the streamwise distance to where maximum streamwise velocity starts to increase are suggested. Some new results on the velocity distribution for the reverse flow for a “bed-jet” flow regime are also presented. Finally, some dimensionless empirical equations describing the relationship between the jet scales for the jet flow in a scour hole and the scour hole size are given

Characterization of Porcine Respiratory Epithelial Cells and Their Innate Immune Responses to Bacterial and Viral Ligands

In response to a pathogenic attack, the host produces a series of defense mechanisms through various intracellular signaling pathways. The byproduct of these signaling pathways helps tackle the invading pathogen and protects the body from getting into a diseased state. This system is called the immune system. The immune system can be divided into two branches namely the innate immune system and adaptive immune system. The groups of immune cells that provide protection regardless of the pathogen specificity constitute the innate immune system. The system that acts according to the pathogen specificity is called the adaptive immune response. The production of antibodies by B cells is a prime example of adaptive immune responses. Macrophages, neutrophils, and monocytes are a few examples of innate immune cells. Besides them, mucosal epithelial cells of the intestinal and respiratory systems are crucial in generating innate immune responses. Invading pathogens and their recognition by the host is pivotal in preventing the subsequent infection and diseases. Epithelial cells express various Pathogen Recognition Receptors (PRRs). These PRRs recognize pathogen-associated molecular patterns (PAMPs) or damage-associated molecular patterns (DAMPs). The binding of PAMPs and/or DAMPs to epithelial cells initiates intracellular signaling pathways that lead to the generation of innate immune responses through the regulation of gene expression. Porcine respiratory epithelial cells and their expression of PRRs render them vital not only for the regulation of innate immune responses but also to study respiratory disease pathogenesis. Ironically, only a handful of studies can be found on these cells and the limited number of studies have hindered our understanding of the role of porcine respiratory cells in innate immunity. In this study, we have characterized previously established porcine primary respiratory epithelial cells from nasal turbinate and trachea followed by their immortalization using hTERT and SV40 large T-antigen. We also studied their innate immune responses to various bacterial and viral ligands. Both the primary and immortalized cells showed typical epithelial cobblestone morphology with a heavy expression of cytokeratin indicating epithelial origin. Cells did not change their morphological characteristics even after immortalization. Immortalization was confirmed by immunofluorescence assay for SV40 and immunocytochemistry for hTERT. However, they did look more granulated than the primary cells. Growth curve analysis showed a faster growth rate of immortalized cells in comparison to the primary cells of both nasal and tracheal origin. Finally, we stimulated the primary cells with various bacterial and viral ligands. Upon stimulation, porcine primary respiratory cells mounted innate immune responses through modulation of the expression of various PRRs and the production of cytokines/chemokines. Modulation of gene expression on mRNA level was measured using ΔΔct method. The research findings may be vital in studying the role of respiratory epithelial cells in the pathogenesis of various respiratory diseases and innate immune responses in pigs

Controlling Electrocatalytic Interfaces using Thin Films and Nanostructures for Energy Applications

The release of greenhouse gases such as CO2 due to various human activities and the use of fossil fuels causes climate change and increases global temperature. For this reason, we must create new technologies that help shift energy production away from fossil fuels to renewable energy sources. Over the past few decades, researchers in academia and industry have focused on developing novel techniques for clean and renewable energy, which could in part be mediated by H2 fuel cells. The oxygen reduction reaction (ORR) occurs at the cathode of fuel cells and is the rate-limiting reaction. Water can be electrolyzed using electricity from renewable sources to generate H2 in a green manner. The oxygen evolution reaction (OER) is the rate-limiting reaction for water electrolysis. Unfortunately, catalysts based on Pt and Ir have the best performance for the ORR and OER, respectively. However, the widespread application of these catalysts is limited because of the high cost and scarcity of Pt- and Ir-based catalysts. Non-precious metal catalysts such as those based on Cu and Ni are promising alternatives. In this dissertation, I have developed a new electrochemical platform that allows for the study of the control of electron and proton transfer in the ORR. Specifically, I use Cu as one of the non-precious metal catalysts to study the ORR. I prepared a dinuclear Cu ORR catalyst that can be covalently attached to thiol-based self-assembled monolayers (SAMs) on Au electrodes using azide-alkyne click chemistry. Using this architecture, the electron transfer rate to the catalyst is modulated by changing the length of the SAM, and the proton transfer rate to the catalyst is controlled with an appended lipid membrane modified with proton carriers. By tuning the relative rates of proton and electron transfer, the current density of the lipid-covered catalyst was enhanced significantly without altering its core molecular structure. Also, I utilized designer small-molecule proton carriers bearing nitrile functional groups that mimic naturally occurring protonophores. These bio-inspired CN-based proton carriers with tailorable proton kinetics were used to turn on the ORR activity of a Cu-based non-precious metal electrocatalyst supported on a modular hybrid bilayer membrane platform under alkaline conditions. In addition, I designed and developed OER electrocatalysts using non-precious metals for energy conversion and storage processes. Hydrogen gas is an alternative fuel that is produced from the electrolysis of water, but technical challenges have heretofore limited the efficiency of water electrolyzers. In order for hydrogen gas to achieve widespread use, it is critical to develop electrocatalysts for the OER that are more cost-effective and widely available than the current state of the art. Thus, I prepared bimetallic electrocatalysts based on Ni and Cu for the OER. I used thin films of Cu2O modified with an overlayer of Ni to construct novel electrocatalysts and determined the optimal ratio of Ni to cuprous oxide for performing the OER in alkaline conditions by tuning the amount of Ni electrodeposited on the Cu2O. Moreover, I developed nanostructured Ni-Cu systems by synthesizing both metallic and bimetallic Ni-Cu nanoclusters and nanoparticles. I found that, for both nanoclusters and nanoparticles, the ratio of Ni to Cu is highly associated with OER electrocatalysis efficiency. Furthermore, I modified carbon electrodes using different compositions of alkyl amine SAMs with various chain lengths and diluent ratios. I investigated the role of defect sites in the SAMs to understand the electron-transfer properties of the appended ferrocene molecules by modifying the SAMs with ZnO electrodeposits. Interestingly, I found that there is a significant change in the electron-transfer rates as a function of SAM linker length when the SAM defect sites are blocked with ZnO electrodeposits. The surface modification protocols used in this study are important in a wide range of applications such as energy catalysis, electroanalysis, and biosensors

Evaluation of wheat chromosome translocation lines for high temperature stress tolerance at grain filling stage

Citation: Pradhan GP, Prasad PVV (2015) Evaluation of Wheat Chromosome Translocation Lines for High Temperature Stress Tolerance at Grain Filling Stage. PLoS ONE 10(2): e0116620. doi:10.1371/journal.pone.0116620High temperature (HT, heat) stress is detrimental to wheat (Triticum aestivum L.) production. Wild relatives of bread wheat may offer sources of HT stress tolerance genes because they grow in stressed habitats. Wheat chromosome translocation lines, produced by introgressing small segments of chromosome from wild relatives to bread wheat, were evaluated for tolerance to HT stress during the grain filling stage. Sixteen translocation lines and four wheat cultivars were grown at optimum temperature (OT) of 22/14°C (day/night). Ten days after anthesis, half of the plants were exposed to HT stress of 34/26°C for 16 d, and other half remained at OT. Results showed that HT stress decreased grain yield by 43% compared with OT. Decrease in individual grain weight (by 44%) was the main reason for yield decline at HT. High temperature stress had adverse effects on leaf chlorophyll content and Fv/Fm; and a significant decrease in Fv/Fm was associated with a decline in individual grain weight. Based on the heat response (heat susceptibility indices, HSIs) of physiological and yield traits to each other and to yield HSI, TA5594, TA5617, and TA5088 were highly tolerant and TA5637 and TA5640 were highly susceptible to HT stress. Our results suggest that change in Fv/Fm is a highly useful trait in screening genotypes for HT stress tolerance. This study showed that there is genetic variability among wheat chromosome translocation lines for HT stress tolerance at the grain filling stage and we suggest further screening of a larger set of translocation lines

The Role of Habitat Types and Soil Physicochemical Properties in the Spread of a Non Native Shrub Lantana Camara in the Doon Valley, Western Himalaya, India

Invasive alien species colonize very aggressively and forcefully, menacing native biodiversity. The success of invasive alien plants is due to their opportunistic exploitation of anthropogenic disturbances, the absence of natural enemies, free from herbivory and frequently their allelopathic competition. Invasive species can have a significant impact on development, affecting sustainability of livelihood, food security and essential ecosystem services and dynamics. Lantana camara is a documented weed of worldwide significance; it is indigestible due to its toxic chemicals and highly competitive. In this study physicochemical properties of soil were analysed from different high and low Lantana infested areas. Significant site effect was frequently observed than effect due to invasion status. The present study tested the impact of soil properties in the measured and calculated attributes of Lantana by randomly sampling soil from the highly invaded and less invaded sites in different habitats using the Modified Whittaker plot design. Results indicated that edaphic factors such as soil pH, total nitrogen, soil organic carbon, phosphorus and potassium content positively influenced the growth of Lantana and helped in its own further invasion process. These factors were also positively influencing the measured and calculated attributes of Lantana such as canopy coverage, average crown diameter, shrub canopy area, phytovolume and biomass from all sites. However some attributes like shrub height and stem diameter were negatively influenced by these soil factors. The present results show that Lantana invasion can significantly improve the soil nutrient level but also positively increasing the chances of its further invasion with more copious plant attributes

Stillbirth in a Tertiary Care Referral Hospital in North Bengal - A Review of Causes, Risk Factors and Prevention Strategies

Background and Aims: Stillbirth is one of the most common adverse outcomes of pregnancy, accounting for half of all perinatal mortality. Each year approximately 4 million stillbirths are reported, with 97% occurring in developing countries. The objective of the present study was to evaluate the stillbirth rate, exploring the risk factors and causes of stillbirth and suggest policies to reduce it. Settings and Design: A retrospective study of stillbirth among all deliveries over 5 years at North Bengal Medical College, a referral tertiary care teaching hospital in a rural background. The stillbirth rate and its trend were defined and the probable causes and risk factors were identified. Results: Stillbirth rate is 59.76/1000 live births, and Perinatal Mortality 98.65/1000 births. Of the still births, 59.72% were fresh and 40.27% were macerated. Among the causes of stillbirths, poor antenatal attendance and low socioeconomic status were important; other risk factors included prematurity, PIH, birth asphyxia, poor intrapartum care including prolonged and obstructed labour. In 23% cases, the cause remained unexplained. Conclusion: In addition to poor antenatal care, low socioeconomic condition, poor referral service, suboptimal intrapartum care in health facilities including tertiary centre were mainly responsible for majority of still births which could have been prevented. We speculate that upgrading the existing health system performance, particularly high quality intrapartum care by skilled health personnel, will reduce stillbirths substantially in our institut