510 research outputs found
Neutrino Constraints on the Dark Matter Total Annihilation Cross Section
In the indirect detection of dark matter through its annihilation products,
the signals depend on the square of the dark matter density, making precise
knowledge of the distribution of dark matter in the Universe critical for
robust predictions. Many studies have focused on regions where the dark matter
density is greatest, e.g., the Galactic Center, as well as on the cosmic signal
arising from all halos in the Universe. We focus on the signal arising from the
whole Milky Way halo; this is less sensitive to uncertainties in the dark
matter distribution, and especially for flatter profiles, this halo signal is
larger than the cosmic signal. We illustrate this by considering a dark matter
model in which the principal annihilation products are neutrinos. Since
neutrinos are the least detectable Standard Model particles, a limit on their
flux conservatively bounds the dark matter total self-annihilation cross
section from above. By using the Milky Way halo signal, we show that previous
constraints using the cosmic signal can be improved on by 1-2 orders of
magnitude; dedicated experimental analyses should be able to improve both by an
additional 1-2 orders of magnitude.Comment: 8 pages, 4 figures; Matches version published in Phys. Rev.
Core-collapse astrophysics with a five-megaton neutrino detector
The legacy of solar neutrinos suggests that large neutrino detectors should be sited underground. However, to instead go underwater bypasses the need to move mountains, allowing much larger water Čerenkov detectors. We show that reaching a detector mass scale of ~5 Megatons, the size of the proposed Deep-TITAND, would permit observations of neutrino “mini-bursts” from supernovae in nearby galaxies on a roughly yearly basis, and we develop the immediate qualitative and quantitative consequences. Importantly, these mini-bursts would be detected over backgrounds without the need for optical evidence of the supernova, guaranteeing the beginning of time-domain MeV neutrino astronomy. The ability to identify, to the second, every core collapse in the local Universe would allow a continuous “death watch” of all stars within ~5 Mpc, making practical many previously-impossible tasks in probing rare outcomes and refining coordination of multiwavelength/multiparticle observations and analysis. These include the abilities to promptly detect otherwise-invisible prompt black hole formation, provide advance warning for supernova shock-breakout searches, define tight time windows for gravitational-wave searches, and identify “supernova impostors” by the nondetection of neutrinos. Observations of many supernovae, even with low numbers of detected neutrinos, will help answer questions about supernovae that cannot be resolved with a single high-statistics event in the Milky Way
Preliminary study and Identification of insects’ species of forensic importance in Urmia, Iran
The proper identification of the insect and arthropod species of forensic importance is the most crucial element in the field of forensic entomology. The main objective in this study was the identification of insects’ species of forensic importance in Urmia (37°, 33 N. and 45°, 4, 45 E.) and establishment of a preliminary data-base for forensic entomology purposes in Iran for the first time. A combination of various body viscera and tissues of some of vertebrates (sheep, cow, fish and hen), such as head, paunch, spleen, intestine, derma and liver was exposed in an open land on the private possession for 53 days. Ambient daily temperature (maximum and minimum) and relative humidity values were recorded; and existing keys were used for identification of different species. During the period of study, rainfall was none; average total temperature was 23.77°C; and average of mean RH or average total RH was 46.41%. Five stages of decomposition were recognized. A total of 3179 individuals were collected; belonging to 5 orders (Diptra, Coleoptera, Hymenoptera, Dermaptera and Blattaria), 11 families, 16 genera and 18 species: Psychoda sp, (Dip. Psychodidae), Calliphora vicina (Dip. Calliphoridae),Calliphora vomitoria (Dip. Calliphoridae), Lucilia sericata (Dip. Calliphoridae), Chrysoma sp. (Dip.Calliphoridae), Musca domestica (Dip. Muscidae), Muscina stabulans (Dip. Muscidae), Fannia canicularis (Dip. Fannidae), Sarcophaga haemorrhoidalis (Dip. Sarcophagidae), Sarcophaga sp. (Dip.Sarcophagidae), Wohlfartia magnifica (Dip. Sarcophagidae), Dermestes maculates (Col. Dermestidae), Necrophorus sp.(Col.Silphidae), Blatta orientalis (Blattaria . Blattidae), Vespula germanica (Hym.Vespidae), Messor caducus (Hym. Formicidae), Cataglyphis sp. (Hym. Formicidae) andForficula auricularia (Dermaptera. Forficulidae). The species of Psychoda sp, (Dip. Psychodidae), M. caducus, Cataglyphis sp. (Hym. Formicidae) and F. auricularia (Dermaptera. Forficulidae) are seldomly reported in previous researches; and they were heavily focused to tissues of animals in these studies
TeV Gamma Rays from Geminga and the Origin of the GeV Positron Excess
The Geminga pulsar has long been one of the most intriguing MeV-GeV gamma-ray
point sources. We examine the implications of the recent Milagro detection of
extended, multi-TeV gamma-ray emission from Geminga, finding that this reveals
the existence of an ancient, powerful cosmic-ray accelerator that can plausibly
account for the multi-GeV positron excess that has evaded explanation. We
explore a number of testable predictions for gamma-ray and electron/positron
experiments (up to ~100 TeV) that can confirm the first "direct" detection of a
cosmic-ray source.Comment: 4 pages and 3 figures; Minor revisions, accepted for publication in
Physical Review Letter
Best-Bet Astrophysical Neutrino Sources
Likely astrophysical sources of detectable high-energy (>> TeV) neutrinos are
considered. Based on gamma-ray emission properties, the most probable sources
of neutrinos are argued to be GRBs, blazars, microquasars, and supernova
remnants. Diffuse neutrino sources are also briefly considered.Comment: 6 pages, 2 figures, in Proc. of TeV-Particle Astrophysics II,
Madison, WI, 28-31 Aug, 200
Pyramiding multiple genes for resistance to PVY, TSWV and PMMoV in pepper using molecular markers
Pepper (Capsicum annuum L.) is one of the most important vegetables cultivated worldwide. Many pests and pathogens cause economic yield losses in pepper. Potato virus Y (PVY), Tomato spotted wilt virus (TSWV) and Pepper mild mottle virus (PMMoV) are considered among the most destructive viruses affecting pepper in the world. Because chemical treatments have limited success for managing PVY, TSWV and PMMoV, resistant varieties are considered to be the most effective means of controlling these viruses. In this study, resistance genes to these viruses were successfully transferred to the superior sweet Charleston pepper line 'Y-CAR' using molecular markers and biological assays. As a result, a new line which is resistant to PVY, TSWV and PMMoV was developed. The results also showed the applicability of a pyramiding strategy for breeding multiple virus resistance in pepper. © Verlag Eugen Ulmer KG, Stuttgart.Scientific and Technological Research Council of Turkey, TEYDEP foundation (3080171
The Star Formation Rate in the Reionization Era as Indicated by Gamma-ray Bursts
High-redshift gamma-ray bursts (GRBs) offer an extraordinary opportunity to
study aspects of the early Universe, including the cosmic star formation rate
(SFR). Motivated by the two recent highest-z GRBs, GRB 080913 at z = 6.7 and
GRB 090423 at z = 8.1, and more than four years of Swift observations, we first
confirm that the GRB rate does not trace the SFR in an unbiased way. Correcting
for this, we find that the implied SFR to beyond z = 8 is consistent with
LBG-based measurements after accounting for unseen galaxies at the faint end of
the UV luminosity function. We show that this provides support for the
integrated star formation in the range 6 < z < 8 to have been alone sufficient
to reionize the Universe.Comment: 4 pages, 4 figures; modified to match version accepted for
publication in ApJ Letter
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