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Distributed Power Control for Multi-Hop Energy Harvesting Links With Retransmission
No full textIn this paper, we consider an energy harvesting (EH) node that periodically takes a measurement and conveys it to a destination over multiple EH relays operating in the decode-and-forward fashion, using the automatic repeat request protocol. Packets that are not delivered to the destination before the next measurement is taken are dropped. We seek to design an online retransmission-index based power control policy (RIP) for each node which minimizes the packet drop probability (PDP). To this end, we first derive an expression for the PDP in terms of the RIPs at the nodes. Next, when the energy cost for decoding a packet is negligible, we obtain closed form expressions for the optimal RIPs. We also extend the results to the case where the peak transmit power is constrained. When the energy cost of decoding is non-negligible, we present a geometric programming based iterative algorithm to obtain near-optimal RIPs. In both the scenarios, in order to obtain insight into the impact of channel coherence time, we design the RIPs for both slow and fast fading channels. Through Monte Carlo simulations, we show that the proposed policies significantly outperform state-of-the-art solutions
SIGNIFICANT REDUCTION IN DROPLET EJECTION FOR TERMINAL VELOCITY IMPACT USING A COMBINATION OF SUPERHYDROPHILIC & SUPERHYDROPHOBIC SIEVE
No full textSuperhydrophobic meshes provide a unique structure that can be used to develop rain-repellent air transparent surfaces. It is however a significant challenge to stop water ejection from these meshes having submillimetre pores when droplets impact them at terminal velocities (V-D similar to 8 m/s). In this work, we have studied the relative velocities of the jets ejected from nanostructured meshes having different geometries and wettabilities. Based on our study we demonstrate a combination of superhydrophilic-superhydrophobic copper mesh which leads to less than 6x10(-4)% liquid ejection for impact of 20 droplets at terminal velocity
Enhancement of target location rates by stochastic modulation of Brownian motion
No full textThe binding of proteins to target sites on DNA, an important trigger of regulatory changes in a cell's life cycle, is a complex biophysical process that is sensitive to details of the surroundings in which it takes place. It is affected, in particular, and among other factors, by thermal noise, by the random binding and unbinding of the protein to the polynucleotide chain, by fluctuations in the chain's conformations, and by the degree of molecular crowding around the reacting species. In this paper, using a model based on dynamically disordered Brownian motion (a model previously introduced to explain the occasional occurrence of non-Gaussian effects in simple random walk behaviour), we show that one such factor-the internal dynamics of DNA-can enhance the rate at which a target on the chain is located by a particle moving randomly along its contour. The enhancement of the target location rate is reminiscent of the phenomenon of stochastic resonance, in that it occurs when the timescale characteristic of the chain's relaxation matches the timescale of the particle's motion. This finding is in qualitative agreement with the few experimental and numerical results to which it can be loosely compared
Modeling Simulation of River Discharge of Loktak Lake Catchment in Northeast India
No full textWater resources management requires an integrated approach between sustainability and catchment management to provide an enhanced understanding of usage options and environmental impacts. Discharge contributes significantly to the lake water and hence its accurate assessment would help in designing the management policies. This study simulates river discharge contributing to a lake using different physical and data-based modeling approaches. Models such as support vector machine (SVM); extreme learning machine (ELM); MIKE SHE; and a combination of MIKE SHE and the Soil and Water Assessment Tool (SWAT), the hybrid MIKE SHE-SWAT model, are used to simulate discharge for three subcatchments of Loktak Lake. Discharge simulation at different sections of a river using physically based models is cumbersome because it requires data such as river geometry, hydrologic time series, channel roughness coefficients, and hydraulics of existing control structures. In developing countries such as India, quality and quantity of data become the limitation because of poor monitoring and record keeping. Therefore, a data-based modeling approach can also be used as an alternative tool in hydrologic simulation studies. The selected methods are evaluated using statistical indicators, and results show that both physical and data-based methods satisfactorily simulate the observed hydrograph at the outlet of each subcatchments. This study concludes that using the hybrid MIKE SHE-SWAT model simulates the river discharge with the highest Nash-Sutcliffe model efficiency (NSE), 0.854 for the Nambul subcatchment, 0.890 for the Iril subcatchment, and 0.845 for the Thoubal subcatchment. Subsequently, hydrological models for the other six subcatchments are developed using the hybrid MIKE SHE-SWAT model. Furthermore, water balance components of the Loktak Lake are also analyzed, which suggest that of the total inflows to the lake, discharge from the nine subcatchments accounts for about 91%, and the remainder is contributed by direct rainfall onto the lake area. Among outflows, Ithai barrage (69%) accounts for the largest fraction, whereas abstractions for hydropower generation, evaporation from the lake surface not covered by phumdis, evapotranspiration from the area of phumdis on the lake, irrigation, and domestic consumption account for 22, 2, 5, 1, and 1%, respectively
DYNAMICS OF VENOM COMPOSITION ACROSS A COMPLEX LIFE CYCLE ARE REVEALED BY THE STUDY OF A MODEL SEA ANEMONE
No full text(Bio)leaching Behavior of Chromite Tailings
No full textChromite beneficiation operations in Sukinda valley (India) produce large amounts of tailings, which are stored in open air. In this study, bioleaching experiments were carried out in batch reactors with Acidithiobacillus thiooxidans or Pseudomonas putida in order to determine the potential leachability of metals contained in these tailings due to biological activity. Acidic and alkaline pH resulted from the incubation of tailings with A. thiooxidans and P. putida, respectively. Tailings were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), and scanning electron microscopy (SEM), and chemical extraction of Cr(VI) with KH2PO4 was performed. Mineralogical investigations showed that tailings are mainly composed of chromite, hematite, lizardite, chlorite, and goethite, which are all known as Cr-bearing phases. During the leaching with A. thiooxidans and P. putida, total Cr was initially extracted as Cr(VI) due to the presence of phosphates in the medium, and subsequently decreased because of Cr(VI) adsorption and reduction to Cr(III). Reduction was associated with bacterial activity, but also with the presence of ferrous iron. Despite the occurrence of siderophores in the tailings after incubation with P. putida, under acidic conditions, Fe extracted remained higher. Extracted Ni, Mn, and Al concentrations also increased over time. Given the significant amount of chromite tailings produced every year, this study shows that tailings storage and leachability represent a potential source of chromium. However, our findings suggest that the presence of bacterial communities, as well as physicochemical processes, favor Cr(VI) reduction
Multifaceted remodeling by vitamin C boosts sensitivity of Mycobacterium tuberculosis subpopulations to combination treatment by anti-tubercular drugs
No full textBacterial dormancy is a major impediment to the eradication of tuberculosis (TB), because currently used drugs primarily target actively replicating bacteria. Therefore, decoding of the critical survival pathways in dormant tubercle bacilli is a research priority to formulate new approaches for killing these bacteria. Employing a network-based gene expression analysis approach, we demonstrate that redox active vitamin C (vit C) triggers a multifaceted and robust adaptation response in Mycobacterium tuberculosis (Mtb) involving similar to 67% of the genome. Vit C-adapted bacteria display well-described features of dormancy, including growth stasis and progression to a viable but non-culturable (VBNC) state, loss of acid-fastness and reduction in length, dissipation of reductive stress through triglyceride (TAG) accumulation, protective response to oxidative stress, and tolerance to first line TB drugs. VBNC bacteria are reactivatable upon removal of vit C and they recover drug susceptibility properties. Vit C synergizes with pyrazinamide, a unique TB drug with sterilizing activity, to kill dormant and replicating bacteria, negating any tolerance to rifampicin and isoniazid in combination treatment in both in-vitro and intracellular infection models. Finally, the vit C multi-stress redox models described here also offer a unique opportunity for concurrent screening of compounds/combinations active against heterogeneous subpopulations of Mtb. These findings suggest a novel strategy of vit C adjunctive therapy by modulating bacterial physiology for enhanced efficacy of combination chemotherapy with existing drugs, and also possible synergies to guide new therapeutic combinations towards accelerating TB treatment
Epitaxial strain modulated electronic properties of interface controlled nickelate superlattices
No full textPerovskite nickelate heterostructures consisting of single unit cells of EuNiO3 and LaNiO3 have been grown on a set of single crystalline substrates by pulsed laser interval deposition to investigate the effect of epitaxial strain on electronic and magnetic properties at the extreme interface limit. Despite the variation of substrate in-plane lattice constants and lattice symmetry, the structural response to heterostructuring is primarily controlled by the presence of the EuNiO3 layer. In sharp contrast to bulk LaNiO3 or EuNiO3, the superlattices grown under tensile strains exhibit metal-to-insulator transitions (MIT) below room temperature. The onset of magnetic and electronic transitions associated with the MIT can be further separated by application of large tensile strain. Furthermore, these transitions can be entirely suppressed by very small compressive strain. X-ray resonant absorption spectroscopy measurements reveal that such strain-controlled MIT is directly linked to a strain-induced self-doping effect without any chemical doping
Clustering of multi-domain protein sequences
No full textThe overall function of a multi-domain protein is determined by the functional and structural interplay of its constituent domains. Traditional sequence alignment-based methods commonly utilize domain-level information and provide classification only at the level of domains. Such methods are not capable of taking into account the contributions of other domains in the proteins, and domain-linker regions and classify multi-domain proteins. An alignment-free protein sequence comparison tool, CLAP (CLAssification of Proteins) was previously developed in our laboratory to especially handle multi-domain protein sequences without a requirement of defining domain boundaries and sequential order of domains. Through this method we aim to achieve a biologically meaningful classification scheme for multi-domain protein sequences. In this article, CLAP-based classification has been explored on 5 datasets of multi-domain proteins and we present detailed analysis for proteins containing (1) Tyrosine phosphatase and (2) SH3 domain. At the domain-level CLAP-based classification scheme resulted in a clustering similar to that obtained from an alignment-based method. CLAP-based clusters obtained for full-length datasets were shown to comprise of proteins with similar functions and domain architectures. Our study demonstrates that multi-domain proteins could be classified effectively by considering full-length sequences without a requirement of identification of domains in the sequence