Three-dimensional electronic instabilities in polymerized solid A1C60

The low-temperature structure of A1C60 (A=K, Rb) is an ordered array of polymerized C60 chains, with magnetic properties that suggest a non-metallic ground state. We study the paramagnetic state of this phase using first-principles electronic-structure methods, and examine the magnetic fluctuations around this state using a model Hamiltonian. The electronic and magnetic properties of even this polymerized phase remain strongly three dimensional, and the magnetic fluctuations favor an unusual three-dimensional antiferromagnetically ordered structure with a semi-metallic electronic spectrum.Comment: REVTeX 3.0, 10 pages, 4 figures available on request from [email protected]

Lymphocyte-Tropic Simian Immunodeficiency Virus Causes Persistent Infection in the Brains of Rhesus Monkeys

AbstractMolecularly cloned SIVmac239 is the prototypical SIVmaclymphocyte-tropic virus that replicates productively in lymphocytes but poorly in macrophages. In macaques, the virus causes activation and productive infection of T lymphocytes which invade the central nervous system (CNS) early after infection in the animal. However, infected animals develop immunosuppression and AIDS but rarely overt neurological disease. In this study, we examined multiple regions of the brain and spinal cord for the presence of SIVenvsequences and histological lesions in five macaques that had been infected with SIVmac239 for 1.7 to 2.25 years. Histopathological examination of the brain revealed no lesions consistent with encephalitis; however, viral DNA was found in all five brains. In one animal the virus caused infection in a widely disseminated pattern from the frontal cortex to the distal end of the spinal cord, whereas in the other four animals infection in the CNS occurred in a nonspecific, focal pattern. Sequence analyses were performed on gp120 sequences isolated from selected regions of the CNS and compared to gp120 sequences isolated from corresponding lymph nodes, a tissue known to support productive replication of SIVmac239. Examination of the viral sequences from the CNS tissue from two animals (macaques 10F and 14F) revealed a low mutation rate when compared to the sequences isolated from the lymph node tissues. The percentage change in the amino acid sequence was approximately 1% for CNS clones versus ≥3% for clones isolated from the lymph node. The majority of the CNS viral sequences of macaques 10F and 14F had none of the genetic markers shown in a previous study to be associated with macrophage-tropic variants and indeed retained a nucleotide sequence of similar to the original lymphocyte-tropic virus used for inoculation despite almost 2 years of persistent infection in the animals. Construction of chimeric viruses with V1–V5 regions of selected macaque 10F and macaque 14F CNS-gp120 clones confirmed the predicted lymphocyte-tropic nature of theseenvgenes. In contrast, the gp120 sequences isolated from the CNS tissue of one of the other three animals (macaque 13F) had a mutation rate comparable to that observed for the lymph node clones. The CNS clones from this animal had amino acid substitutions that were previously shown to be associated with macrophage tropism. Compared to the chimeric viruses constructed with V1–V5 sequences from macaques 10F and 14F, viruses constructed with the V1–V5 sequences of several macaque 13F brain clones did not yield infectious virus. These data suggest that following entry into the CSF early during infection in the animals, SIVmac239 caused infection in the CNS. In some animals, the viralenvsequences recovered by the PCR suggested that minimal replication had occurred, whereas in another macaque virus replication had progressed with gradual selection of a more macrophage-tropic genotype

Estimation of vortex density after superconducting film quench

This paper addresses the problem of vortex formation during a rapid quench in a superconducting film. It builds on previous work showing that in a local gauge theory there are two distinct mechanisms of defect formation, based on fluctuations of the scalar and gauge fields, respectively. We show how vortex formation in a thin film differs from the fully two-dimensional case, on which most theoretical studies have focused. We discuss ways of testing theoretical predictions in superconductor experiments and analyse the results of recent experiments in this light.Comment: 7 pages, no figure

Ballynahone Bog SAC Wind Data Analysis October 2020 to September 2021.

Local prevailing wind patterns play a key role in atmospheric nitrogen (N) input to designated sites, in terms of local ammonia (NH3) concentrations and N deposition originating from local, regional and transboundary sources. The aim of this study is to investigate local wind patterns and their temporal variability using locally measured weather data for the period October 2020 to September 2021 on Ballynahone Bog. These data were analysed in conjunction with NH3 measurements within and surrounding Ballynahone Bog SAC (Thomas et al. 2020; Williams et al. 2021). This report aims to assess local wind patterns for the period October 2020 to September 2021 and establish how local wind patterns influence NH3 concentrations on Ballynahone Bog

Atmospheric ammonia assessments on six designated sites in Northern Ireland. Year 1: June 2020 – May 2021

Report to DAERA NIEA (Project 07102). Atmospheric ammonia (NH3) gas concentrations were monitored on six designated sites of international and national importance (Special Areas of Conservation, SAC and Areas of Special Scientific Interest (ASSI)) across Northern Ireland, to assess threats from atmospheric nitrogen inputs. The monitoring strategy at each designated site aims to capture the high spatial variability of NH3 and any associated atmospheric concentration gradients away from sources, where the highest concentrations (and local sources) may be and where the largest ecosystem impacts are likely to occur. The sites are also part of the cross-border INTERREG Va funded Collaborative Action for the Natura Network (CANN) project (2017-2021), managed by the Special EU Programmes Body. The measurement data will provide supporting evidence to develop site-specific mitigation strategies, if necessary and appropriate. It is hypothesised that boundaries of a designated site that are closest to, and downwind of sources (e.g. intensive livestock units) will be exposed to the highest NH3 concentrations and therefore most at risk from adverse effects on sensitive vegetation. This report presents monthly NH3 measurements from the first year of monitoring, between June 2020 and May 2021

Ballynahone Bog SAC Wind Data Analysis October 2021 to March 2022.

Local prevailing wind patterns play a key role in atmospheric nitrogen (N) input to designated sites, in terms of local ammonia (NH3) concentrations and N deposition originating from local, regional and transboundary sources. The aim of this study is to investigate local wind patterns and their temporal variability using locally measured weather data. These data were analysed in conjunction with NH3 measurements within and surrounding Ballynahone Bog SAC. This report is part of a series that started to analyse data from month-year, with the period investigated in the current report being 1st October 2021 to 31st March 2022. This report aims to assess local wind patterns for the period October 2021 to March 2022 and establish how local wind patterns influence NH3 concentrations

A Grand Canonical Ensemble Approach to the Thermodynamic Properties of the Nucleon in the Quark-Gluon Coupling Model

In this paper, we put forward a way to study the nucleon's thermodynamic properties such as its temperature, entropy and so on, without inputting any free parameters by human hand, even the nucleon's mass and radius. First we use the Lagrangian density of the quark gluon coupling fields to deduce the Dirac Equation of the quarks confined in the gluon fields. By boundary conditions we solve the wave functions and energy eigenvalues of the quarks, and thus get energy-momentum tensor, nucleon mass, and density of states. Then we utilize a hybrid grand canonical ensemble, to generate the temperature and chemical potentials of quarks, antiquarks of three flovars by the four conservation laws of the energy and the valence quark numbers, after which, all other thermodynamic properties are known. The only seemed free paremeter, the nucleon radius is finally determined by the grand potential minimal principle.Comment: 5 pages, LaTe

Extragalactic neutrino background from very young pulsars surrounded by supernova envelopes

We estimate the extragalactic muon neutrino background which is produced by hadrons injected by very young pulsars at an early phase after supernova explosion. It is assumed that hadrons are accelerated in the pulsar wind zone which is filled with thermal photons captured below the expanding supernova envelope. In collisions with those thermal photons hadrons produce pions which decay into muon neutrinos. At a later time, muon neutrinos are also produced by the hadrons in collisions with matter of the expanding envelope. We show that extragalactic neutrino background predicted by such a model should be detectable by the planned 1 km$^2$ neutrino detector if a significant part of pulsars is born with periods shorter than $\sim 10$ ms. Since such population of pulsars is postulated by the recent models of production of extremely high energy cosmic rays, detection of neutrinos with predicted fluxes can be used as their observational test.Comment: 4 pages, 2 figures, A&A style, accepted to A&A Let

Measuring Cosmic Defect Correlations in Liquid Crystals

From the theory of topological defect formation proposed for the early universe, the so called Kibble mechanism, it follows that the density correlation functions of defects and anti-defects in a given system should be completely determined in terms of a single length scale $\xi$, the relevant domain size. Thus, when lengths are expressed in units of $\xi$, these distributions should show universal behavior, depending only on the symmetry of the order parameter, and space dimensions. We have verified this prediction by analyzing the distributions of defects/anti-defects formed in the isotropic-nematic phase transition in a thin layer of nematic liquid crystals. Our experimental results confirm this prediction and are in reasonable agreement with the results of numerical simulations.Comment: 15 pages, 4 figures, minor changes, few new references adde

Nonequilibrium Evolution of Correlation Functions: A Canonical Approach

We study nonequilibrium evolution in a self-interacting quantum field theory invariant under space translation only by using a canonical approach based on the recently developed Liouville-von Neumann formalism. The method is first used to obtain the correlation functions both in and beyond the Hartree approximation, for the quantum mechanical analog of the $\phi^{4}$ model. The technique involves representing the Hamiltonian in a Fock basis of annihilation and creation operators. By separating it into a solvable Gaussian part involving quadratic terms and a perturbation of quartic terms, it is possible to find the improved vacuum state to any desired order. The correlation functions for the field theory are then investigated in the Hartree approximation and those beyond the Hartree approximation are obtained by finding the improved vacuum state corrected up to ${\cal O}(\lambda^2)$. These correlation functions take into account next-to-leading and next-to-next-to-leading order effects in the coupling constant. We also use the Heisenberg formalism to obtain the time evolution equations for the equal-time, connected correlation functions beyond the leading order. These equations are derived by including the connected 4-point functions in the hierarchy. The resulting coupled set of equations form a part of infinite hierarchy of coupled equations relating the various connected n-point functions. The connection with other approaches based on the path integral formalism is established and the physical implications of the set of equations are discussed with particular emphasis on thermalization.Comment: Revtex, 32 pages; substantial new material dealing with non-equilibrium evolution beyond Hartree approx. based on the LvN formalism, has been adde