30,780 research outputs found
Dark matter and neutrino masses in the R-parity violating NMSSM
The R-Parity symmetry Violating (RPV) version of the Next-to-Minimal
Supersymmetric Standard Model (NMSSM) is attractive simultaneously with regard
to the so-called mu-problem and the accommodation of three-flavor neutrino data
at tree level. In this context, we show here that if the Lightest
Supersymmetric Particle (LSP) is the gravitino, it possesses a lifetime larger
than the age of the universe since its RPV induced decay channels are
suppressed by the weak gravitational strength. This conclusion holds if one
considers gravitino masses ~ 10^2 GeV like in supergravity scenarios, and is
robust if the lightest pseudoscalar Higgs field is as light as ~ 10 GeV [as may
occur in the NMSSM]. For these models predicting in particular an RPV
neutrino-photino mixing, the gravitino lifetime exceeds the age of the universe
by two orders of magnitude. However, we find that the gravitino cannot
constitute a viable dark matter candidate since its too large RPV decay widths
would then conflict with the flux data of last indirect detection experiments.
The cases of a sneutrino LSP or a neutralino LSP as well as the more promising
gauge-mediated supersymmetry breaking scenario are also discussed. Both the
one-flavor simplification hypothesis and the realistic scenario of three
neutrino flavors are analyzed. We have modified the NMHDECAY program to extend
the neutralino mass matrix to the present framework.Comment: Latex file, 23 pages, 7 figures. References added and discussion on
the indirect detection modifie
SUSY radiative corrections on mu-tau neutrino refraction including possible R-parity breaking interactions
In this paper we investigate the one-loop radiative corrections to the
neutrino indices of refraction from supersymmetric models. We consider the
Next-to Minimal Supersymmetric extension of the Standard Model (NMSSM) which
happens to be a better supersymmetric candidate than the MSSM for both
theoretical and experimental reasons. We scan the relevant SUSY parameters and
identify regions in the parameter space which yield interesting values for
V_{mu tau}. If R-parity is broken there are significant differences between
MSSM and NMSSM contributions contrary to the R-parity conserved case. Finally,
for a non-zero CP-violating phase, we show analytically that the presence of
V_{mu tau} will explicitly imply CP-violation effects on the supernova electron
(anti-) neutrino fluxes.Comment: 23 pages, 15 figures; v2: typos and 5 figures correcte
From parasite genomes to one healthy world: Are we having fun yet?
In 1990, the Human Genome Sequencing Project was established. This laid the ground work for an explosion of sequence data that has since followed. As a result of this effort, the first complete genome of an animal, Caenorhabditis elegans was published in 1998. The sequence of Drosophila melanogaster was made available in March, 2000 and in the following year, working drafts of the human genome were generated with the completed sequence (92%) being released in 2003. Recent advancements and next-generation technologies have made sequencing common place and have infiltrated every aspect of biological research, including parasitology. To date, sequencing of 32 apicomplexa and 24 nematode genomes are either in progress or near completion, and over 600k nematode EST and 200k apicomplexa EST submissions fill the databases. However, the winds have shifted and efforts are now refocusing on how best to store, mine and apply these data to problem solving. Herein we tend not to summarize existing X-omics datasets or present new technological advances that promise future benefits. Rather, the information to follow condenses up-to-date-applications of existing technologies to problem solving as it relates to parasite research. Advancements in non-parasite systems are also presented with the proviso that applications to parasite research are in the making
Long-range sound propagation: A review of some experimental data
Three experimental studies of long range sound propagation carried out or sponsored in the past by NASA are briefly reviewed to provide a partial prospective for some of the analytical studies presented in this symposium. The three studies reviewed cover (1) a unique test of two large rocket engines conducted in such a way as to provide an indication of possible atmospheric scattering loss from a large low-frequency directive sound source, (2) a year-long measurement of low frequency sound propagation which clearly demonstrated the dominant influence of the vertical gradient in the vector sound velocity towards the receiver in defining excess sound attenuation due to refraction, and (3), a series of excess ground attenuation measurements over grass and asphalt surfaces replicated several times under very similar inversion weather conditions
Notes on the Life cycle of \u3ci\u3eNemoria Rubrifrontaria\u3c/i\u3e (Lepidoptera: Geometridae)
(excerpt)
While surveying for insect pests of sweet fern, Myrica aspleniifolia L., two unidentified eggs were detected on foliage samples collected in June 1972 near Barton City, Alcona County, Michigan. the eggs were transferred to petri dishes with sweet fern foliage for rearing. Subsequently, one of the larvae that emerged was reared to adulthood and identified as Nemoria rubrifrontaria Packard. This note describes the life cycle of this insect
Organocatalytic Lewis base functionalisation of carboxylic acids, esters and anhydrides via C1-ammonium or azolium enolates
This tutorial review highlights the organocatalytic Lewis base functionalisation of carboxylic acids, esters and anhydrides via C1-ammonium/azolium enolates. The generation and synthetic utility of these powerful intermediates is highlighted through their application in various methodologies including aldol-lactonisations, Michael-lactonisations/lactamisations and [2,3]-rearrangements.Publisher PDFPeer reviewe
Life History, Damage, and Gall Development of the Gall Midge, \u3ci\u3eNeolasioptera Brevis\u3c/i\u3e (Diptera: Cecidomyiidae), Injurious to Honeylocust in Michigan
Neolasioptera brevis is univoltine in Michigan. Adults issue in late spring, and females deposit eggs in rows on the lower side of young shoots of honeylocust. Larval eclosion occurs shortly after: there are three larval instars. The gall is polythalamous and may have 20 or more larvae. The third-instar larvae overwinter, and pupation occurs in spring. The gall injury kills sorne shoots, but most damage is cosmetic. One can monitor for adult emergence in late April or May by observing cast pupal cases protruding from the gall. Control, if needed, should be directed at adults
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