Ground state phase diagram of a spinless, extended Falicov-Kimball model on the triangular lattice

Correlated systems with hexagonal layered structures have come to fore with renewed interest in Cobaltates, transition-metal dichalcogenides and GdI2. While superconductivity, unusual metal and possible exotic states (prevented from long range order by strong local fluctuations) appear to come from frustration and correlation working in tandem in such systems, they freeze at lower temperature to crystalline states. The underlying effective Hamiltonian in some of these systems is believed to be the Falicov-Kimball model and therefore, a thorough study of the ground state of this model and its extended version on a non-bipartite lattice is important. Using a Monte Carlo search algorithm, we identify a large number of different possible ground states with charge order as well as valence and metal-insulator transitions. Such competing states, close in energy, give rise to the complex charge order and other broken symmetry structures as well as phase segregations observed in the ground state of these systems.Comment: 9 pages, 7 figure

Analytical parametrization of fusion barriers using proximity potentials

Using the three versions of proximity potentials, namely proximity 1977, proximity 1988, and proximity 2000, we present a pocket formula for fusion barrier heights and positions. This was achieved by analyzing as many as 400 reactions with mass between 15 and 296. Our parametrized formula can reproduced the exact barrier heights and positions within an accuracy of $\pm1$. A comparison with the experimental data is also in good agreement.Comment: 12 pages, 5 figure

An extended Falicov-Kimball model on a triangular lattice

The combined effect of frustration and correlation in electrons is a matter of considerable interest of late. In this context a Falicov-Kimball model on a triangular lattice with two localized states, relevant for certain correlated systems, is considered. Making use of the local symmetries of the model, our numerical study reveals a number of orbital ordered ground states, tuned by the small changes in parameters while quantum fluctuations between the localized and extended states produce homogeneous mixed valence. The inversion symmetry of the Hamiltonian is broken by most of these ordered states leading to orbitally driven ferroelectricity. We demonstrate that there is no spontaneous symmetry breaking when the ground state is inhomogeneous. The study could be relevant for frustrated systems like $GdI_2$, $NaTiO_2$ (in its low temperature C2/m phase) where two Mott localized states couple to a conduction band.Comment: 6 pages, 8 figure

Nonlinear Stability in the Generalised Photogravitational Restricted Three Body Problem with Poynting-Robertson Drag

The Nonlinear stability of triangular equilibrium points has been discussed in the generalised photogravitational restricted three body problem with Poynting-Robertson drag. The problem is generalised in the sense that smaller primary is supposed to be an oblate spheroid. The bigger primary is considered as radiating. We have performed first and second order normalization of the Hamiltonian of the problem. We have applied KAM theorem to examine the condition of non-linear stability. We have found three critical mass ratios. Finally we conclude that triangular points are stable in the nonlinear sense except three critical mass ratios at which KAM theorem fails.Comment: Including Poynting-Robertson Drag the triangular equilibrium points are stable in the nonlinear sense except three critical mass ratios at which KAM theorem fail

Orthogonal, metal-free surface modification by strain-promoted azide–alkyne and nitrile oxide–alkene/alkyne cycloadditions

In this article we present a fast and efficient methodology for biochemical surface patterning under extremely mild conditions. Micropatterned azide/benzaldoxime-surfaces were prepared by microcontact printing of a heterobifunctional cyclooctyne oxime linker on azide-terminated self-assembled monolayers (SAMs). Strain-promoted azide–alkyne cycloaddition (SPAAC) in combination with microcontact printing allows fast and effective surface patterning. The resulting bifunctional azide/oxime substrates could successfully be used for metal-free, orthogonal immobilization of various biomolecules by 1,3-dipolar cycloadditions at room temperature. Azide-decorated areas were modified by reaction with a cyclooctyne-conjugate using SPAAC, while benzaldoxime-decorated areas were activated by in situ oxidation to the reactive nitrile oxides and subsequent nitrile oxide cycloaddition with alkene- and alkyne-functionalized bioconjugates. In addition, orthogonal double immobilization was achieved by consecutive and independent SPAAC and nitrile oxide cycloadditions

Non-linear stability in photogravitational non-planar restricted three body problem with oblate smaller primary

We have discussed non-linear stability in photogravitational non-planar restricted three body problem with oblate smaller primary. By photogravitational we mean that both primaries are radiating. We normalised the Hamiltonian using Lie transform as in Coppola and Rand (1989). We transformed the system into Birkhoff's normal form. Lie transforms reduce the system to an equivalent simpler system which is immediately solvable. Applying Arnold's theorem, we have found non-linear stability criteria. We conclude that $L_6$ is stable. We plotted graphs for $(\omega_1, D_2).$ They are rectangular hyperbola.Comment: Accepted for publication in Astrophysics & Space Scienc

Linear Stability of Equilibrium Points in the Generalized Photogravitational Chermnykh's Problem

The equilibrium points and their linear stability has been discussed in the generalized photogravitational Chermnykh's problem. The bigger primary is being considered as a source of radiation and small primary as an oblate spheroid. The effect of radiation pressure has been discussed numerically. The collinear points are linearly unstable and triangular points are stable in the sense of Lyapunov stability provided $\mu< \mu_{Routh}=0.0385201$. The effect of gravitational potential from the belt is also examined. The mathematical properties of this system are different from the classical restricted three body problem

Neonatal health in Nepal: analysis of absolute and relative inequalities and impact of current efforts to reduce neonatal mortality

Background: Nepal has made substantial progress in reducing under-five mortality and is on track to achieve Millennium Development Goal 4, but advances in neonatal health are less encouraging. The objectives of this study were to assess relative and absolute inequalities in neonatal mortality over time, and to review experience with major programs to promote neonatal health. Methods: Using four nationally representative surveys conducted in 1996, 2001, 2006 and 2011, we calculated neonatal mortality rates for Nepal and for population groups based on child sex, geographical and socio-economic variables using a true cohort log probability approach. Inequalities based on different variables and years were assessed using rate differences (rd) and rate ratios (rr); time trends in neonatal mortality were measured using the annual rate of reduction. Through literature searches and expert consultation, information on Nepalese policies and programs implemented since 1990 and directly or indirectly attempting to reduce neonatal mortality was compiled. Data on timeline, coverage and effectiveness were extracted for major programs. Results: The annual rate of reduction for neonatal mortality between 1996 and 2011 (2.8 percent per annum) greatly lags behind the achievements in under-five and infant mortality, and varies across population groups. For the year 2011, stark absolute and relative inequalities in neonatal mortality exist in relation to wealth status (rd = 21.4, rr = 2.2); these are less pronounced for other measures of socio-economic status, child sex and urban-rural residence, ecological and development region. Among many efforts to promote child and maternal health, three established programs and two pilot programs emerged as particularly relevant to reducing neonatal mortality. While these were designed based on national and international evidence, information about coverage of different population groups and effectiveness is limited. Conclusion: Neonatal mortality varies greatly by socio-demographic variables. This study clearly shows that much remains to be achieved in terms of reducing neonatal mortality across different socio-economic, ethnic and geographical population groups in Nepal. In moving forward it will be important to scale up programs of proven effectiveness, conduct in-depth evaluation of promising new approaches, target unreached and hard-to-reach populations, and maximize use of financial and personnel resources through integration across programs

CASE REPORT ON UNILATERAL SEGMENTAL CALCIFICATION OF STYLOHYOID LIGAMENT

An unusual case of a unilaterally elongated styloid process with a length of 6.8 cm was found on orthopantomogram (OPG) of male patient. The patient reported with ipsilateralotalgia presumably due to nerve compression from the elongated styloid process. The symptomatology appeared by such an anatomical variant as well as relative literature is discussed in the present case. KEYWORDS: Styloid process; Otalgia; Stylohyoid ligament; orthopantomogram

CASE REPORT ON UNILATERAL SEGMENTAL CALCIFICATION OF STYLOHYOID LIGAMENT

An unusual case of a unilaterally elongated styloid process with a length of 6.8 cm was found on orthopantomogram (OPG) of male patient. The patient reported with ipsilateralotalgia presumably due to nerve compression from the elongated styloid process. The symptomatology appeared by such an anatomical variant as well as relative literature is discussed in the present case. KEYWORDS: Styloid process; Otalgia; Stylohyoid ligament; orthopantomogram