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ON EXTENSION PROBLEM, TRACE HARDY AND HARDY'S INEQUALITIES FOR SOME FRACTIONAL LAPLACIANS
No full textWe obtain generalised trace Hardy inequalities for fractional powers of general operators given by sums of squares of vector fields. Such inequalities are derived by means of particular solutions of an extended equation associated to the above-mentioned operators. As a consequence, Hardy inequalities are also deduced. Particular cases include Laplacians on stratified groups, Euclidean motion groups and special Hermite operators. Fairly explicit expressions for the constants are provided. Moreover, we show several characterisations of the solutions of the extension problems associated to operators with discrete spectrum, namely Laplacians on compact Lie groups, Hermite and special Hermite operators
U-Pb geochronology of zircons from river sediments in Sri Lanka: Implications on early Archean to late Cambrian magmatism and episodic crustal growth
No full textGeochronology of zircons from river-sediments in Sri Lanka has never been attempted. Here we present Rare Earth Elements (REE) and U-Pb isotopes of -700 zircon grains by laser ablation ICP-MS technique, from sediments of the major rivers in the Sri Lankan basement (rivers of Mahaweli, Kelani, Kalu, Walawe, Maduru Oya and Maha Oya). Most of the studied zircons display oscillatory zoning and Th/U > 0.1, confirming their igneous origin. U-Pb age distribution of these river-sand zircons exhibits two major populations depicting Mesoproterozoic to Archean ( similar to 30%; > 1100-3100 Ma) and Neoproterozoic to late Cambrian ( similar to 70%; > 430-1000 Ma) magmatism. The two populations could be further resolved into intensive and episodic magmatic peaks at 480-680 Ma, 680-1000 Ma, 1100-1300 Ma, 1300-1700 Ma, 1700-1900 Ma, 2100-2300 Ma, 2300-2600 Ma and 2600-3100 Ma. These river-sediment-zircon data are consistent with the principal episodes of global continental crustal growth and the recognized U-Pb ages of magmatism are mostly correlative with those obtained from basement rocks by previous studies of Sri Lanka. The older zircons found in this study may have mainly originated from reworked/recycled ancient (Palaoproterozoic to Archean) crust. A younger zircon group of 450-700 Ma with homogenous core-rim zoning texture and Th/U ratios < 0.1 were inferred to be of metamorphic origin, indicating their possible crystallization at late Neoproterozoic metamorphic events, associated with the final assembly of the Gondwana Supercontinent. Thus, our data imply that the present-day continental crust of Sri Lanka may have predominantly formed and grown in the Neoproterozoic, while there is evidence that crustal growth began at least in the Paleoproterozoic. Further, the Mesoproterozoic peaks of the frequency distribution of U-Pb ages of river-sand zircons at similar to 1.6 Ga and similar to 1.1 Ga might reflect triggering of subduction in a paleo tectonic setting forming the Wanni and Vijayan dual arc systems, respectively
Greywater treatment in aerobic bio-reactor with macropore mesh filters
No full textThe aerobic treatment technologies such as membrane bioreactor (MBR) and sequential batch reactor (SBR) fail to address the techno-economic challenges of a small scale, household greywater (GW) treatment, therefore this research proposes a novel, amended, aerobic bioreactor design containing a macroporous nylon mesh filter (MF), submerged in aerobic bioreactor (MMBR) for the simultaneous treatment and particulate filtration of wastewater not limited to only GW. The research was focused on understanding the interplay of MF submerged depth, the orientation of MF (vertical and horizontal) and mesh pore sizes (50 mu m and 100 mu m) on the effluent quality and fluxes. The performance of MMBRs was mainly influenced by the MF orientation and its submerged depth in the reactors, whereas, MF pore sizes had no consequential impact on the performances. Higher rates of biofouling in horizontally positioned 100 mu m MF coincided with the gradual reduction in effluent flux from 1.6 m(3)/m(2).h to nearly 0.2 m(3)/m(2).h, relatively lower effluent COD of 50 mg/1 (90% removal) and turbidity of 29 NTU (56% reduction). In contrast, the continuous self-erosion of biofilm from the horizontally positioned 50 mu m MF discharged effluent with relatively higher COD, turbidity and flux respectively. Metagenomic analysis revealed the domination of phylum Proteobacteria and several microbial communities known to degrade recalcitrant household chemical compounds (HCPs). The microbial community dynamics of MF biofilm was distinctive to the suspended microbes in its vicinity, with a comparatively lower microbial population and diversity with respect to the suspended microbes
Blue-Shifted Hydrogen Bonding in the Gas Phase CH/D3CN center dot center dot center dot HCCl3 Complexes
No full textBlue-shifting H-bonded complexes between CHCl3 and CH/D3CN have been identified by Fourier transform infrared spectroscopy in the gas phase at room temperature. The change in FTIR peak intensity of the mixture of the two components as a function of temperature and composition provides the basis for identification of the H-bonded band in the infrared spectrum. On complex formation with CH3CN and CD3CN, the C-H stretching frequency of CHCl3 shifts to the blue by +8.7 and +8.6 cm(-1), respectively. The molecular electrostatic potential calculation at the MP2/6-311++G** level has been used to arrive at the geometry of the complex. It has been reported in the literature that CHCl3 and CH/D3CN form red-shifting H-bonded complex in Ar matrix. The red shifting has been verified by doing ab initio calculations in the presence of Ar atoms, which has been attributed to the matrix effect at low temperature. The interaction of Ar with CH3CN makes the CH3CN more basic and as a result it becomes better hydrogen bond acceptor and causes red shift. The potential energy scans and NBO analysis of the Cl3CH center dot center dot center dot NCCH3 complex have been compared with those of F3CH center dot center dot center dot NCCH3 and Cl3CH center dot center dot center dot NH3 complexes. The change in electron density of the CHCl3 as a function of C-H center dot center dot center dot N distance shows that the approach of CH3CN to CHCl3 induces a shift in electron density from the H atom to the Cl atoms of CHCl3 which leads to C-H bond contraction and blue shifting of C-H stretching frequency. However, in the complex Cl3CH center dot center dot center dot NH3, where frequency shift to the red is reported, charge transfer and electrostatic interaction dominate
Mechanisms of Spindle Positioning: Lessons from Worms and Mammalian Cells
No full textProper positioning of the mitotic spindle is fundamental for specifying the site for cleavage furrow, and thus regulates the appropriate sizes and accurate distribution of the cell fate determinants in the resulting daughter cells during development and in the stem cells. The past couple of years have witnessed tremendous work accomplished in the area of spindle positioning, and this has led to the emergence of a working model unravelling in-depth mechanistic insight of the underlying process orchestrating spindle positioning. It is evident now that the correct positioning of the mitotic spindle is not only guided by the chemical cues (protein-protein interactions) but also influenced by the physical nature of the cellular environment. In metazoans, the key players that regulate proper spindle positioning are the actin-rich cell cortex and associated proteins, the ternary complex (G alpha/GPR-1/2/LIN-5 in Caenorhabditis elegans, Gi/Pins/Mud in Drosophila and Gi(1-3)/LGN/NuMA in humans), minus-end-directed motor protein dynein and the cortical machinery containing myosin. In this review, I will mainly discuss how the abovementioned components precisely and spatiotemporally regulate spindle positioning by sensing the physicochemical environment for execution of flawless mitosis
Search for resonant t(t)over-bar production in proton-proton collisions at root s=13 TeV
No full textA search for a heavy resonance decaying into a top quark and antiquark (tt) pair is performed using proton-proton collisions at p s = 13TeV. The search uses the data set collected with the CMS detector in 2016, which corresponds to an integrated luminosity of 35.9 fb. The analysis considers three exclusive fi nal states and uses reconstruction techniques that are optimized for top quarks with high Lorentz boosts, which requires the use of nonisolated leptons and jet substructure techniques. No signi fi cant excess of events relative to the expected yield from standard model processes is observed. Upper limits on the production cross section of heavy resonances decaying to a tt pair are calculated. Limits are derived for a leptophobic topcolor Z 0 resonance with widths of 1, 10, and 30%, relative to the mass of the resonance, and exclude masses up to 3.80, 5.25, and 6.65TeV, respectively. Kaluza-Klein excitations of the gluon in the Randall-Sundrum model are excluded up to 4.55TeV. To date, these are the most stringent limits on tt resonances
Search for W Boson Decays to Three Charged Pions
No full textFor the first time, a search for the rare decay of the W boson to three charged pions has been performed. Proton-proton collision data recorded by the CMS experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 77.3 fb(-1), have been analyzed. No significant excess is observed above the background expectation. An upper limit of 1.01 x 10(-6) is set at 95% confidence level on the branching fraction of the W boson to three charged pions. This provides a strong motivation for theoretical calculations of this branching fraction
Crystallographic Structures of IlvN center dot Val/Ile Complexes: Conformational Selectivity for Feedback Inhibition of Aceto Hydroxy Acid Synthases
No full textConformational factors that predicate selectivity for valine or isoleucine binding to IlvN leading to the regulation of aceto hydroxy acid synthase I (AHAS I) of Escherichia coli have been determined for the first time from high-resolution (1.9-2.43 angstrom) crystal structures of IlvN center dot Val and IlvN center dot Ile complexes. The valine and isoleucine ligand binding pockets are located at the dimer interface. In the IlvN center dot Ile complex, among residues in the binding pocket, the side chain of Cys(43) is 2-fold disordered (chi(1) angles of gauche(-) and trans). Only one conformation can be observed for the identical residue in the IlvN center dot Val complexes. In a reversal, the side chain of His(53), located at the surface of the protein, exhibits two conformations in the IlvN center dot Val complex. The concerted conformational switch in the side chains of Cys(43) and His(53) may play an important role in the regulation of the AHAS I holoenzyme activity. A significant result is the establishment of the subunit composition in the AHAS I holoenzyme by analytical ultracentrifugation. Solution nuclear magnetic resonance and analytical ultracentrifugation experiments have also provided important insights into the hydrodynamic properties of IlvN in the ligand-free and -bound states. The structural and biophysical data unequivocally establish the molecular basis for differential binding of the ligands to IlvN and a rationale for the resistance of IlvM to feedback inhibition by the branched-chain amino acids
Remote Sensing of Cloud Ice Water Path from SAPHIR Microwave Sounder Onboard Megha- Tropiques
No full textThis study derives the ice water path of the atmospheric column from the microwave sounder SAPHIR onboard Megha-Tropiques. SAPHIR (Sondeur Atmospherique du Profil d'Humidite Intertropicale par Radiometrie) is a cross-track, multichannel microwave humidity sounder with six channels ranging from 183.3 +/- 0.2 to 183.3 +/- 11GHz near the 183.31GHz water vapor absorption line. It measures the earth emitted radiation at these six frequencies. In this paper, Concurrent and collocated observations of Channel 183.31 +/- 6.6GHz, and 183.3 +/- 11GHz from SAPHIR and IWP (Ice water Path) from CloudSat have been used in the development the algorithm. A total of five sets of neural network model, each for 10 degrees of incidence angle of SAPHIR have been developed. The model shows a correlation of 0.83 and RMSE of 195g/m(2) with an independent test dataset. The validation of the algorithm has been done by comparing the retrieval with various satellite derived IWP products such as CloudSat, GMI (Global precipitation measuring mission Microwave Imager) and MSPPS (Microwave Surface and Precipitation Products System). The instantaneous comparisons of IWP over a cyclonic storm ROANU demonstrate a good agreement between NN (Neural Network) derived IWP and CloudSat. A probability distribution of IWP indicates consistency between SAPHIR and CloudSat. A comparison of zonal mean between all the IWP products shows that SAPHIR performs better than GMI, and MSPPS
Unraveling the mechanistic effects of electric field stimulation towards directing stem cell fate and function: A tissue engineering perspective
No full textElectric field (EF) stimulation can play a vital role in eliciting appropriate stem cell response. Such an approach is recently being established to guide stem cell differentiation through osteogenesis/neurogenesis/cardiomyogenesis. Despite significant recent efforts, the biophysical mechanisms by which stem cells sense, interpret and transform electrical cues into biochemical and biological signals still remain unclear. The present review critically analyses the variety of EF stimulation approaches that can be employed to evoke appropriate stem cell response and also makes an attempt to summarize the underlying concepts of this notion, placing special emphasis on stem cell based tissue engineering and regenerative medicine. This review also discusses the major signaling pathways and cellular responses that are elicited by electric stimulation, including the participation of reactive oxygen species and heat shock proteins, modulation of intracellular calcium ion concentration, ATP production and numerous other events involving the clustering or reassembling of cell surface receptors, cytoskeletal remodeling and so on. The specific advantages of using external electric stimulation in different modalities to regulate stem cell fate processes are highlighted with explicit examples, in vitro and in vivo. (C) 2017 Elsevier Ltd. All rights reserved