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Scope of self-interacting thermal WIMPs in a minimal U(1)(D) extension and its future prospects
No full textIn this work we have considered a minimal extension of Standard Model by a local U(1) gauge group in order to accommodate a stable (fermionic) Dark Matter (DM) candidate. We have focussed on parameter regions where DM possesses adequate self-interaction, owing to the presence of a light scalar mediator (the dark Higgs), alleviating some of the tensions in the small-scale structures. We have studied the scenario in the light of a variety of data, mostly from dark matter direct searches, collider searches and flavor physics experiments, with an attempt to constrain the interactions of the standard model (SM) particles with the ones in the Dark Sector (DS). Assuming a small gauge kinetic mixing parameter, we find that for rather heavy DM the most stringent bound on the mixing angle of the Dark Higgs with the SM Higgs boson comes from dark matter direct detection experiments, while for lighter DM, LHC constraints become more relevant. Note that, due to the presence of very light mediators, the effective operator approach to the direct detection is inapplicable here and these constraints have been re-evaluated for our scenario. In addition, we find that the smallness of the relevant portal couplings, as dictated by data, critically suppress the viability of DM production by the standard ``freeze-out'' mechanism in such simplified scenarios. In particular, the viable DM masses are less than or similar to O(2) GeV i.e. in the regions where direct detection limits tend to become weak. For heavier DM with large self-interactions, we hence conclude that non-thermal production mechanisms are favored. Lastly, future collider reach of such a simplified scenario has also been studied in detail
Inflammatory Effects of Subacute Exposure of Roundup in Rat Liver and Adipose Tissue
No full textRoundup is a popular herbicide containing glyphosate as an active ingredient. The formulation of Roundup is speculated to have critical toxic effects, one among which is chronic inflammation. The present study analyzed adverse inflammatory effects in the liver and adipose tissue of rats after a subacute exposure of Roundup. Adult male rats were exposed to various doses of Roundup (0, 5, 10, 25, 50, 100 and 250 mg/kg bodyweight bw] glyphosate) orally, everyday for 14 days. On day 15, liver and adipose tissues from dosed rats were analyzed for inflammation markers. C-reactive protein in liver, cytokines IL-1 beta, TNF-alpha, IL-6, and inflammatory response marker, and prostaglandin-endoperoxide synthase were upregulated in liver and adipose of rats exposed to higher (100 and 250 mg/kg bw/d) doses of Roundup. Cumulatively, our data suggest development of inflammation in lipid and hepatic organs upon exposure to Roundup. Furthermore, liver histological studies showed formation of vacuoles, fibroid tissue, and glycogen depletion in the groups treated with doses of higher Roundup. These observations suggest progression of fatty liver disease in Roundup-treated adult rats. In summary, our data suggest progression of multiorgan inflammation, liver scarring, and dysfunction post short-term exposure of Roundup in adult male rats
Enantioselective 4+2]-Annulation of Azlactones with Copper-Allenylidenes under Cooperative Catalysis: Synthesis of alpha-Quaternary alpha-Acylaminoamides
No full textThe first enantioselective decarboxylative 4 + 2]-annulation of ethynyl benzoxazinanones with azlactones has been developed under cooperative copper and bifunctional tertiary aminourea catalysis. This direct and modular approach combines dipolar copper-allenylidene intermediates with azlactone enolates and allows for the synthesis of alpha-quaternary alpha-acylaminoamides as a single diastereomer generally in high yields with good to excellent enantioselectivities (up to 99:1 er)
On the Broadcast Rate and Fractional Clique Cover of Single Unicast Index Coding Problems
No full textThe broadcast rate beta of an index coding problem is the minimum number of index code symbols required to transmit to satisfy the demands of all the receivers. The linear broadcast rate beta((l)) of an index coding problem is the minimum number of index code symbols obtained by linear encoding by using a encoding matrix. Blasiak et al. defined the fractional clique cover number of an undirected graph and used it to bound the broadcast rate of an index coding problem. Lubetzky et al. proved that nonlinear codes can outperform linear codes. In this paper, we find the fractional clique cover number of two classes of symmetric index coding problems. For single unicast index coding problems with symmetric consecutive and neighboring side-information, we prove that broadcast rate is equal to the fractional clique cover number. We define m-dimensional vector index code of an index coding problem by using disjunctive product of side-information graph. We prove that if linear broadcast rate is equal to fractional clique cover number, then, linear broadcast rate is equal to broadcast rate
Biophysical implications of Maxwell stress in electric field stimulated cellular microenvironment on biomaterial substrates
No full textA number of experimental studies have established the critical role of electric field stimulation on cell functionality modulation of various cell types on a wide range of biomaterial platforms in vitro. In particular, cell fate processes, morphological changes and electroporation are significantly modulated over a narrow range of electric field stimulation conditions. Although a few studies using electrical network theory, first principle simulations and electrohydrodynamic models are reported in the literature, the present study establishes a theoretical foundation to a new perspective that bioelectric stress can significantly influence cell morphological changes/electroporation and in a broader sense, the cell response to electric field on biomaterial substrates. A single cell is modelled as a spherical membrane separating the culture medium and the cytoplasm having different dielectric properties. The analytical solutions to the Laplace equation and Poisson equation for the system are adopted to quantitatively capture the potential distribution in the cellular microenvironment for different cases. These include a cell on a conducting substrate, on an insulating substrate and a cell with surface charge density, in electric field stimulated cellular microenvironment. The biophysical significance of the normal stress distribution has been discussed in terms of the variation in the cellular deformation, depending on the frequency of the electric field and substrate conductivity. A significant difference has been observed in the deformation behavior at higher frequencies (>10(9) Hz) compared to low frequency and DC electric fields. This theoretical study therefore unravels the significance of substrate conductivity in synergy with electric field parameters to modulate cell response. In addition, the tangential component of the Maxwell stress tensor (shear stress), a measure of the stretching force on the membrane, has been used to obtain estimates of the critical electric field required for membrane rupture. It has been predicted that a cell with surface charge density requires electric fields of the order of 10 kV/mm in order to undergo membrane rupture, which is in line with the experimental observations reported in the literature. Taken together, the presented analysis is expected to provide guidelines to develop next generation biomaterials and biomedical devices for regenerative medicine and cancer treatments
Optical Float-Zone Grown Bulk beta-Ga2O3-Based Linear MSM Array of UV-C Photodetectors
No full textIn this letter, we demonstrate 1 x 8 linear metal-semiconductor-metal arrays of UV-C photodetectors based on optical-float-zone grown bulk (100)-oriented beta-Ga2O3. The as-grown polished bulk samples exhibited an RMS roughness of 1.4 nm and the full-width at half-maxima of 0.19 degrees. The average peak responsivity (257 nm), dark current, photo-to-dark current ratio, and UV-to-visible rejection ratio of the devices in the array were measured to be 4 AW(-1), 0.23 nA, similar to 10(2), and similar to 10(3), respectively, at a bias of 40 V. The uniformity as well as the variability of the detector parameters across the devices in the array was investigated before and after wire bonding
Stability of Stochastic Approximations With ``Controlled Markov'' Noise and Temporal Difference Learning
No full textWe are interested in understanding stability (almost sure boundedness) of stochastic approximation algorithms (SAs) driven by a ``controlled Markov'' process. Analyzing this class of algorithms is important, since many reinforcement learning (RL) algorithms can be cast as SAs driven by a ``controlled Markov'' process. In this paper, we present easily verifiable sufficient conditions for stability and convergence of SAs driven by a ``controlled Markov'' process. Many RL applications involve continuous state spaces. While our analysis readily ensures stability for such continuous state applications, traditional analyses do not. As compared to literature, our analysis presents a two-fold generalization: 1) the Markov process may evolve in a continuous state space and 2) the process need not be ergodic under any given stationary policy. Temporal difference (TD) learning is an important policy evaluation method in RL. The theory developed herein, is used to analyze generalized TD(0), an important variant of TD. Our theory is also used to analyze a TD formulation of supervised learning for forecasting problems
The hills are alive with geckos! A radiation of a dozen species on sky islands across peninsular India (Squamata: Gekkonidae, Hemiphyllodactylus) with the description of three new species
No full textSky Islands are high-elevation environments that are separated by warmer, low elevations, forming natural patches of unique montane habitat that often persist through changing climates. Peninsular India was ancestrally forested and has gradually become more arid since at least the Oligocene, and open landscapes have dominated since the middle-late Miocene. Mesic forests today are largely restricted to coastal mountains and some other montane habitats. A mitochondrial phylogeny and fossil-calibrated timetree of Indian Hemiphyllodactylus reveal an Indochinese origin and an endemic radiation with 12 species-level lineages, where a single species was known, that diversified in the Oligocene-Miocene across montane forest habitats in the Eastern Ghats and south India. The phylogeny also suggests the discontinuous Eastern Ghats mountain range encompasses two distinct biogeographic entities: north and south of the Pennar/Krishna-Godavari River basins. This studyhighlights the deep history of the region and the importance of montane habitats as islands of unique biodiversity that have persisted through millions of years of changing climates. We describe three new species: Hemiphyllodactylus arakuensis sp. nov., H. jnana sp. nov. and H. kolliensis sp. nov. from montane habitats above 1000m. The montane habitats of these species are emerging hotspots of reptile endemism, and this study emphasizes the need for systematic biodiversity inventory across India to uncover basic patterns of diversity and distribution
Estimating the kinetic temperature from H I 21-cm absorption studies: correction for turbulence broadening
No full textThe neutral hydrogen 21-cm transition is a useful tracer of the neutral interstellar medium. However, it is often not straightforward to infer physical conditions from the observed 21-cm absorption and/or emission spectra. One complication when estimating the temperature of the atomic gas is that the linewidth can have a significant contribution from non-thermal broadening. Here, we propose a formalism to separate the thermal and non-thermal broadening using a self-consistent model of turbulence broadening of the HI 21-cm absorption components. By applying this novel method, we have estimated the spin and the kinetic temperature of diffuse Galactic neutral hydrogen, and we have found that a large fraction of gas has a temperature in the unstable range. The turbulence is found to be subsonic or transonic in nature, and the clouds seem to have a bimodal size distribution. Assuming that the turbulence is magnetohydrodynamic in nature, the estimated magnetic field strength is of mu G order, and is found to be uncorrelated with the H I number density
Thermoelectric properties of Mn doped BiCuSeO
No full textBiCuSeO is a promising thermoelectric material having earth-abundant non-toxic constituents and favourable thermoelectric properties like ultra-low thermal conductivity. In this study, Mn+2 has been introduced at the Bi+3 site to increase hole concentration as well as Seebeck coefficient, through aliovalent doping and magnetic impurity incorporation respectively. Samples were prepared through two-step solid state synthesis with the composition Bi1-xMnxCuSeO(x = 0.0, 0.04, 0.06, 0.08, 0.10 and 0.12). X-ray diffraction patterns confirmed the tetragonal (space group: P4/ nmm) crystal structure of BiCuSeO as well as phase purity of the samples. The Seebeck coefficient and electrical resistivity had a decreasing trend with increasing doping fraction owing to the generation of charge carriers. The samples with x = 0.04 and 0.06 showed temperature independent Seebeck coefficient above 523 K, which is a signature of small polaron hopping. While the Seebeck coefficient of the samples with x = 0.08, 0.10 and 0.12 increased above 523 K due to the combination of localized and extended states. The thermal conductivity was dominated by the lattice part of the thermal conductivity. As a result of moderate Seebeck coefficient and low electrical resistivity, the highest power factor of 0.284 mW m(-1)-K-2 was obtained for the Bi Mn-0.92 ( 0.08) CuSeO at 773 K, leading to a maximum zT of 0.4 at 773