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Ertel potential vorticity, Bernoulli streamfunction, planetary-scale hydraulic jumps, and transonic jet-streaks in a re-analysis of the Martian atmosphere
Malaria-filaria coinfection in mice makes malarial disease more severe unless filarial infection achieves patency
Coinfections are common in natural populations, and the literature suggests that helminth coinfection readily affects how the immune system manages malaria. For example, type 1–dependent control of malaria parasitemia might be impaired by the type 2 milieu of preexisting helminth infection. Alternatively, immunomodulatory effects of helminths might affect the likelihood of malarial immunopathology. Using rodent models of lymphatic filariasis (Litomosoides sigmodontis) and noncerebral malaria (clone AS Plasmodium chabaudi chabaudi), we quantified disease severity, parasitemia, and polyclonal splenic immune responses in BALB/c mice. We found that coinfected mice, particularly those that did not have microfilaremia (Mf), had more severe anemia and loss of body mass than did mice with malaria alone. Even when controlling for parasitemia, malaria was most severe in Mf coinfected mice, and this was associated with increased interferon-g responsiveness. Thus, in Mf mice, filariasis upset a delicate immunological balance in malaria infection and exacerbated malaria-induced immunopathology. Helminth infections are prevalent throughout tropical regions where malaria is transmitted [1–5]. Interactions among infections commonly alter disease severity [6, 7], and malaria-helminth coinfection can either exac
Prospects for the Standard Model Higgs Boson Search in the LEP 2000 Run
A study has been performed of the discovery and exclusion potential of LEP expected in 2000 for the Higgs bosonpredicted by the Standard Model. The tradeoff factors betweenincreasing the luminosity at GeV and reduced integrated luminosity at GeVwere studied. It was shown that only in case some evidencefor a signal is observed it might be worth to increase the integratedluminosity at the lower center-of-mass energy, otherwise,LEP should aim at the highest possible center-of-mass energy.The ultimate expected exclusion limit (at the 95\%\ confidence level)of LEP (with GeV) is estimated to be 114 GeV
Dense loops, supersymmetry, and Goldstone phases in two dimensions
Loop models in two dimensions can be related to O(N) models. The
low-temperature dense-loops phase of such a model, or of its reformulation
using a supergroup as symmetry, can have a Goldstone broken-symmetry phase for
N<2. We argue that this phase is generic for -2< N <2 when crossings of loops
are allowed, and distinct from the model of non-crossing dense loops first
studied by Nienhuis [Phys. Rev. Lett. 49, 1062 (1982)]. Our arguments are
supported by our numerical results, and by a lattice model solved exactly by
Martins et al. [Phys. Rev. Lett. 81, 504 (1998)].Comment: RevTeX, 5 pages, 3 postscript figure
Inferring the neutron star equation of state from binary inspiral waveforms
The properties of neutron star matter above nuclear density are not precisely
known. Gravitational waves emitted from binary neutron stars during their late
stages of inspiral and merger contain imprints of the neutron-star equation of
state. Measuring departures from the point-particle limit of the late inspiral
waveform allows one to measure properties of the equation of state via
gravitational wave observations. This and a companion talk by J. S. Read
reports a comparison of numerical waveforms from simulations of inspiraling
neutron-star binaries, computed for equations of state with varying stiffness.
We calculate the signal strength of the difference between waveforms for
various commissioned and proposed interferometric gravitational wave detectors
and show that observations at frequencies around 1 kHz will be able to measure
a compactness parameter and constrain the possible neutron-star equations of
state.Comment: Talk given at the 12th Marcel Grossman Meeting, Paris, France, 12-18
Jul 200
Spin-Peierls states of quantum antiferromagnets on the lattice
We discuss the quantum paramagnetic phases of Heisenberg antiferromagnets on
the 1/5-depleted square lattice found in . The possible phases of
the quantum dimer model on this lattice are obtained by a mapping to a
quantum-mechanical height model. In addition to the ``decoupled'' phases found
earlier, we find a possible intermediate spin-Peierls phase with
spontaneously-broken lattice symmetry. Experimental signatures of the different
quantum paramagnetic phases are discussed.Comment: 9 pages; 2 eps figure
Non-abelian statistics of half-quantum vortices in p-wave superconductors
Excitation spectrum of a half-quantum vortex in a p-wave superconductor
contains a zero-energy Majorana fermion. This results in a degeneracy of the
ground state of the system of several vortices. From the properties of the
solutions to Bogoliubov-de-Gennes equations in the vortex core we derive the
non-abelian statistics of vortices identical to that for the Moore-Read
(Pfaffian) quantum Hall state.Comment: 5 pages, 3 figures, REVTeX, epsf. Reference adde
Confinement of Slave-Particles in U(1) Gauge Theories of Strongly-Interacting Electrons
We show that slave particles are always confined in U(1) gauge theories of
interacting electron systems. Consequently, the low-lying degrees of freedom
are different from the slave particles. This is done by constructing a dual
formulation of the slave-particle representation in which the no-double
occupany constraint becomes linear and, hence, soluble. Spin-charge separation,
if it occurs, is due to the existence of solitons with fractional quantum
numbers
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