Metal Chalcogenide Clusters with Closed Electronic Shells and the Electronic Properties of Alkalis and Halogens

Clusters with filled electronic shells and a large gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) are generally energetically and chemically stable. Enabling clusters to become electron donors with low ionization energies or electron acceptors with high electron affinities usually requires changing the valence electron count. Here we demonstrate that a metal cluster may be transformed from an electron donor to an acceptor by exchanging ligands while the neutral form of the clusters has closed electronic shells. Our studies on Co6Te8(PEt3),(CO) (m + n = 6) clusters show that Co6Te8(PEt3)(6) has a closed electronic shell and a low ionization energy of 4.74 eV, and the successive replacement of PEt3 by CO ligands ends with Co6Te8(CO)(6) exhibiting halogen-like behavior. Both the low ionization energy Co6Te8(PEt3)(6) and high electron affinity Co6Te8(CO)(6) have closed electronic shells marked by high HOMO-LUMO gaps of 1.24 and 1.39 eV, respectively. Further, the clusters with an even number of ligands favor a symmetrical placement of ligands around the metal core

Perturbativity constraints on U(1)B−LU(1)_{B-L} and left-right models and implications for heavy gauge boson searches

We derive perturbativity constraints on beyond standard model scenarios with extra gauge groups, such as $SU(2)$ or $U(1)$, whose generators contribute to the electric charge, and show that there are both upper and lower limits on the additional gauge couplings, from the requirement that the couplings remain perturbative up to the grand unification theory (GUT) scale. This leads to stringent constraints on the masses of the corresponding gauge bosons and their collider phenomenology. We specifically focus on the models based on $SU(2)_L\times U(1)_{I_{3R}} \times U(1)_{B-L}$ and the left-right symmetric models based on $SU(2)_L\times SU(2)_R\times U(1)_{B-L}$, and discuss the implications of the perturbativity constraints for new gauge boson searches at current and future colliders. In particular, we find that the stringent flavor constraints in the scalar sector of left-right model set a lower bound on the right-handed scale $v_R \gtrsim 10$ TeV, if all the gauge and quartic couplings are to remain perturbative up to the GUT scale. This precludes the prospects of finding the $Z_R$ boson in the left-right model at the LHC, even in the high-luminosity phase, and leaves only a narrow window for the $W_R$ boson. A much broader allowed parameter space, with the right-handed scale $v_R$ up to $\simeq 87$ TeV, could be probed at the future 100 TeV collider.Comment: 30 pages, 9 figures, 4 tables, minor changes, version to be published in JHE

QQˉQ\bar Q (Q∈{b,c}Q\in \{b, c\}) spectroscopy using Cornell potential

The mass spectra and decay properties of heavy quarkonia are computed in nonrelativistic quark-antiquark Cornell potential model. We have employed the numerical solution of Schr\"odinger equation to obtain their mass spectra using only four parameters namely quark mass ($m_c$, $m_b$) and confinement strength ($A_{c\bar c}$, $A_{b\bar b}$). The spin hyperfine, spin-orbit and tensor components of the one gluon exchange interaction are computed perturbatively to determine the mass spectra of excited $S$, $P$, $D$ and $F$ states. Digamma, digluon and dilepton decays of these mesons are computed using the model parameters and numerical wave functions. The predicted spectroscopy and decay properties for quarkonia are found to be consistent with available experimental observations and results from other theoretical models. We also compute mass spectra and life time of the $B_c$ meson without additional parameters. The computed electromagnetic transition widths of heavy quarkonia and $B_c$ mesons are in tune with available experimental data and other theoretical approaches

The Effect of Mg Doping on Structural and Luminescent Properties of Barium Strontium Titanate (BST)

AbstractPure and Mg doped barium strontium titanate (BST) phosphor samples are prepared by solid state reaction (SSR) method at 1300°c. The prepared samples are characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-VIS absorption spectroscopy. The optical properties are studied in terms of mechanoluminescence (ML) and thermoluminescence (TL). The XRD results reveal perovskite structure of samples with XRD peaks corresponding to planes (100), (110), (111), (200) and (211). The SEM micrographs exhibit agglomeration of particles of different shapes. The particle size calculated using SEM and XRD data is found to lie in nano range. The ML intensity is found to depend on applied load while the TL intensity increases with increasing irradiation time

Predictions from non trivial Quark-Lepton complementarity

The complementarity between the quark and lepton mixing matrices is shown to provide robust predictions. We obtain these predictions by first showing that the matrix V_M, product of the quark (CKM) and lepton (PMNS) mixing matrices, may have a zero (1,3) entry which is favored by experimental data. We obtain that any theoretical model with a vanishing (1,3) entry of V_M that is in agreement with quark data, solar, and atmospheric mixing angle leads to $\theta_{13}^{PMNS}=(9{^{+1}_{-2}})^\circ$. This value is consistent with the present 90% CL experimental upper limit. We also investigate the prediction on the lepton phases. We show that the actual evidence, under the only assumption that the correlation matrix V_M product of CKM and PMNS has a zero in the entry (1,3), gives us a prediction for the three CP-violating invariants J, S_1, and S_2. A better determination of the lepton mixing angles will give stronger prediction for the CP-violating invariants in the lepton sector. These will be tested in the next generation experiments. Finally we compute the effect of non diagonal neutrino mass in "l_i -> l_j gamma" in SUSY theories with non trivial Quark-Lepton complementarity and a flavor symmetry. The Quark-Lepton complementarity and the flavor symmetry strongly constrain the theory and we obtain a clear prediction for the contribution to "mu -> e gamma" and the "tau" decays "tau -> e gamma" and "tau -> mu gamma". If the Dirac neutrino Yukawa couplings are degenerate but the low energy neutrino masses are not degenerate, then the lepton decays are related among them by the V_M entries. On the other hand, if the Dirac neutrino Yukawa couplings are hierarchical or the low energy neutrino masses are degenerate, then the prediction for the lepton decays comes from the CKM hierarchy.Comment: 15 pages, 5 figures, ws-ijmpa class included, Proceedings of the CTP Symposium on Sypersymmetry at LH

Man-eating and cattle-lifting by tigers and conservation implications in India

Chauhan, N.P.S

Clinical significance of presence of accessory foramen transversarium in typical cervical vertebrae

Background: The cervical vertebrae are smallest of all the vertebrae present in the vertebral column. It is characterized by a foramen in each transverse process. The foramen transversarium (FT) of 6th to 1st cervical vertebrae transmits vertebral vessels and sympathetic nerves. Presence of another foramen apart from FT in the transverse process of cervical vertebrae is called accessory FT. Anatomical knowledge of these variations are helpful for conducting cervical spinal surgeries by the surgeons in order to prevent injury to vertebral vessels and sympathetic nerves.Methods: The present study was conducted in the department of anatomy, UCMS and GTB Hospital, Delhi, India. A total number of 241 dried cervical vertebrae were collected from the bone bank of the Department of Anatomy. Presence of any variation from the normal anatomy of the cervical vertebrae were noted and photographed.Results: Out of 241 cervical vertebrae (typical and atypical), the accessory FT was noted in typical cervical vertebrae only. Accessory FT was seen in 37 (27.6%) vertebrae, out of 134 typical cervical vertebrae. These accessory FT were either bilateral complete in 4 (2.9%) or incomplete 9 (6.7%) or unilateral complete 6 (4.5%) and unilateral incomplete 12 (8.9%) were observed. Six (4.5%) typical cervical vertebrae showed presence of complete accessory FT on one side and incomplete accessory FT on the other side in the same vertebra.Conclusions: Knowledge of variations of the presence of accessory FT in the typical cervical vertebrae is not only important to anatomist but also to radiologist in identifying the presence of duplicate vertebral artery and hence helping the neuro surgeons in preventing accidental bleeding from the vertebral artery while performing surgery on the cervical spine

Human casualties and agricultural crop raiding by wild pigs and mitigation strategies in India

Chauhan, N.P.S

Agricultural crop depredation by nilgai antelope (Boselaphus tragocamelus) and mitigation strategies: challenges in India

Chauhan, N.P.S

Recognition of Human Actions in Video

Recognition and analysis of Human actions is an important task in the area of computer vision. There are many applications of this research which include surveillance systems, patient monitoring systems, human performance analysis, con tent - based image/video retrieval/storage, virtual reality and a variety of syst ems that involve interactions between persons or interactions between person and devices, etc. The need for such system is increasing day - by - day, with the increase in number of surveillance cameras deployed in public spaces. Automated systems are required that can detect, categorize and recognize human activities and request the human attention only when necessary. In this paper, important steps of such a system are described that can robustly tracks human in various environments and recognizes their actions through image sequences acquired from a single fixed camera. The overall system consists of major th ree steps: blob extraction, feature extraction, and human action recognition. Given the sequence of images, a statistical method is demonstrated to extract the blobs and to remove the shadows and highlights in order to obtain a more accurate object silhouet te. Shape context is used to extract features in next step and at - last human action is recognized using neural networ