3,391 research outputs found
Report drawn up on behalf of the Committee on the Environment, Public Health and Consumer Protection on the proposal from the Commission of the European Communities to the Council for a directive amending for the sixth time the Council Directive of 23 October 1962 on the approximation of the rules of the Member States concerning the colouring matters authorized for use in foodstuffs intended for human consumption. Working Documents 1977-1978, Document 455/77, 15 December 1977
Report by the Committee on Public Health and the Environment on the Activities of the European Communities which fall within the terms of reference of the committee (Doc. 500/74). Working Documents 1975-1976, Document 149/75, 27 June 1975
Symmetry breaking in the self-consistent Kohn-Sham equations
The Kohn-Sham (KS) equations determine, in a self-consistent way, the
particle density of an interacting fermion system at thermal equilibrium. We
consider a situation when the KS equations are known to have a unique solution
at high temperatures and this solution is a uniform particle density. We show
that, at zero temperature, there are stable solutions that are not uniform. We
provide the general principles behind this phenomenon, namely the conditions
when it can be observed and how to construct these non-uniform solutions. Two
concrete examples are provided, including fermions on the sphere which are
shown to crystallize in a structure that resembles the C molecule.Comment: a few typos eliminate
Quasi-exact-solution of the Generalized Exe Jahn-Teller Hamiltonian
We consider the solution of a generalized Exe Jahn-Teller Hamiltonian in the
context of quasi-exactly solvable spectral problems. This Hamiltonian is
expressed in terms of the generators of the osp(2,2) Lie algebra. Analytical
expressions are obtained for eigenstates and eigenvalues. The solutions lead to
a number of earlier results discussed in the literature. However, our approach
renders a new understanding of ``exact isolated'' solutions
Breeding latitude predicts timing but not rate of spring migration in a widespread migratory bird in South America
Identifying the processes that determine avian migratory strategies in different environmental contexts is imperative to understanding the constraints to survival and reproduction faced by migratory birds across the planet. We compared the spring migration strategies of Fork‐tailed Flycatchers (Tyrannus s. savana) that breed at south‐temperate latitudes (i.e., austral migrants) vs. tropical latitudes (i.e., intratropical migrants) in South America. We hypothesized that austral migrant flycatchers are more time‐selected than intratropical migrants during spring migration. As such, we predicted that austral migrants, which migrate further than intratropical migrants, will migrate at a faster rate and that the rate of migration for austral migrants will be positively correlated with the onset of spring migration. We attached light‐level geolocators to Fork‐tailed Flycatchers at two tropical breeding sites in Brazil and at two south‐temperate breeding sites in Argentina and tracked their movements until the following breeding season. Of 286 geolocators that were deployed, 37 were recovered ~1 year later, of which 28 provided useable data. Rate of spring migration did not differ significantly between the two groups, and only at one site was there a significantly positive relationship between date of initiation of spring migration and arrival date. This represents the first comparison of individual migratory strategies among conspecific passerines breeding at tropical vs. temperate latitudes and suggests that austral migrant Fork‐tailed Flycatchers in South America are not more time‐selected on spring migration than intratropical migrant conspecifics. Low sample sizes could have diminished our power to detect differences (e.g., between sexes), such that further research into the mechanisms underpinning migratory strategies in this poorly understood system is necessary.Fil: Jahn, Alex. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Cereghetti, Joaquín. Universidad Nacional de La Pampa; ArgentinaFil: Cueto, Víctor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagóica. Universidad Nacional de la Patagonia "San Juan Bosco". Facultad de Ciencias Naturales - Sede Esquel. Centro de Investigación Esquel de Montaña y Estepa Patagónica; ArgentinaFil: Hallworth, Michael T.. Smithsonian Conservation Biology Institute; Estados UnidosFil: Levey, Douglas J.. National Science Foundation; Estados UnidosFil: Marini, Miguel Â.. Universidade do Brasília; BrasilFil: Masson, Diego. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; ArgentinaFil: Pizo, Marco A.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Sarasola, José Hernán. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La Pampa. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La Pampa; ArgentinaFil: Tuero, Diego Tomas. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentin
Crossover Between Universality Classes in the Statistics of Rare Events in Disordered Conductors
The crossover from orthogonal to the unitary universality classes in the
distribution of the anomalously localized states (ALS) in two-dimensional
disordered conductors is traced as a function of magnetic field. We demonstrate
that the microscopic origin of the crossover is the change in the symmetry of
the underlying disorder configurations, that are responsible for ALS. These
disorder configurations are of weak magnitude (compared to the Fermi energy)
and of small size (compared to the mean free path). We find their shape
explicitly by means of the direct optimal fluctuation method.Comment: 7 pages including 2 figure
Gender differences in retention and survival on antiretroviral therapy of HIV-1 infected adults in Malawi
BackgroundThere is currently a dearth of knowledge on gender differences in mortality among patients on ART in Africa. MethodsUsing data from the national ART monitoring and evaluation system, a survival analysis of all healthcare workers, teachers, and police/army personnel who accessed ART in Malawi by June, September and December 2006 respectively, was undertaken. Gender differences in survival were analysed using Kaplan-Meier estimates and rate ratios were derived from Poisson regression adjusting for confounding.Results4670 ART patients (49.8% female) were followed up for a median of 8.7 months after starting ART. Probability of death was significantly higher for men than women (
Leitfaden Saatgutgesundheit im Ökologischen Landbau - Gemüsekulturen
Im "Leitfaden Saatgutgesundheit im Ökologischen Landbau – Gemüsekulturen" werden ausgewählte saatgutbürtige Krankheiten von ackerbaulichen Kulturen samt vorbeugenden und direkten Regulierungsmöglichkeiten vorgestellt
Composite Polarons in Ferromagnetic Narrow-band Metallic Manganese Oxides
A new mechanism is proposed to explain the colossal magnetoresistance and
related phenomena. Moving electrons accompanied by Jahn-Teller phonon and
spin-wave clouds may form composite polarons in ferromagnetic narrow-band
manganites. The ground-state and finite-temperature properties of such
composite polarons are studied in the present paper. By using a variational
method, it is shown that the energy of the system at zero temperature decreases
with the formation of composite polaron; the energy spectrum and effective mass
of the composite polaron at finite temperature is found to be strongly
renormalized by the temperature and the magnetic field. It is suggested that
the composite polaron contribute significantly to the transport and the
thermodynamic properties in ferromagnetic narrow-band metallic manganese
oxides.Comment: Latex, no figur
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