13,445 research outputs found
Generalized WDVV equations for B_r and C_r pure N=2 Super-Yang-Mills theory
A proof that the prepotential for pure N=2 Super-Yang-Mills theory associated
with Lie algebras B_r and C_r satisfies the generalized WDVV
(Witten-Dijkgraaf-Verlinde-Verlinde) system was given by Marshakov, Mironov and
Morozov. Among other things, they use an associative algebra of holomorphic
differentials. Later Ito and Yang used a different approach to try to
accomplish the same result, but they encountered objects of which it is unclear
whether they form structure constants of an associative algebra. We show by
explicit calculation that these objects are none other than the structure
constants of the algebra of holomorphic differentials.Comment: 8 page
Second order reductions of the WDVV Equations related to classical Lie algebras
We construct second order reductions of the generalized
Witten-Dijkgraaf-Verlinde-Verlinde system based on simple Lie algebras. We
discuss to what extent some of the symmetries of the WDVV system are preserved
by the reduction.Comment: 6 pages, 1 tabl
The spanish influenza pandemic: a lesson from history 100 years after 1918
In Europe in 1918, influenza spread through Spain, France, Great Britain and Italy, causing havoc with military operations during the First World War. The influenza pandemic of 1918 killed more than 50 million people worldwide. In addition, its socioeconomic consequences were huge. "Spanish flu", as the infection was dubbed, hit different agegroups, displaying a so-called "W-trend", typically with two spikes in children and the elderly. However, healthy young adults were also affected. In order to avoid alarming the public, several local health authorities refused to reveal the numbers of people affected and deaths. Consequently, it was very difficult to assess the impact of the disease at the time. Although official communications issued by health authorities worldwide expressed certainty about the etiology of the infection, in laboratories it was not always possible to isolate the famous Pfeiffer's bacillus, which was, at that time, deemed to be the cause of influenza. The first official preventive actions were implemented in August 1918; these included the obligatory notification of suspected cases and the surveillance of communities such as day-schools, boarding schools and barracks. Identifying suspected cases through surveillance, and voluntary and/or mandatory quarantine or isolation, enabled the spread of Spanish flu to be curbed. At that time, these public health measures were the only effective weapons against the disease, as no vaccines or antivirals were available. Virological and bacteriological analysis of preserved samples from infected soldiers and other young people who died during the pandemic period is a major step toward a better understanding of this pandemic and of how to prepare for future pandemics
Search for B0s → μ+μ− and B0 → μ+μ− decays in CMS
A search for the rare decays B0s → μ+μ− and B0 → μ+μ−
performed in pp collisions at √s = 7TeV is presented. The data sample, collected by the CMS experiment at the LHC, corresponds to an integrated luminosity of about 5 fb−1,
corresponding to all 2011 data taking
Efficacy of Two Common Methods of Application of Residual Insecticide for Controlling the Asian Tiger Mosquito, Aedes albopictus (Skuse), in Urban Areas
After its first introduction in the 1980's the Asian tiger mosquito, Aedes albopictus (Skuse), has spread throughout Southern Europe. Ae. albopictus is considered an epidemiologically important vector for the transmission of many viral pathogens such as the yellow fever virus, dengue fever and Chikungunya fever, as well as several filarial nematodes such as Dirofilaria immitis or D. repens. It is therefore crucial to develop measures to reduce the risks of disease transmission by controlling the vector populations. The aim of the study was to compare the efficacy of two application techniques (mist vs. stretcher sprayer) and two insecticides (Etox based on the nonester pyrethroid Etofenprox vs. Microsin based on the pyrethroid type II Cypermetrin) in controlling adult tiger mosquito populations in highly populated areas. To test the effect of the two treatments pre- and post-treatment human landing rate counts were conducted for two years. After one day from the treatment we observed a 100% population decrease in mosquito abundance with both application methods and both insecticides. However, seven and 14 days after the application the stretcher sprayer showed larger population reductions than the mist sprayer. No effect of insecticide type after one day and 14 days was found, while Etox caused slightly higher population reduction than Microsin after seven days. Emergency measures to locally reduce the vector populations should adopt adulticide treatments using stretcher sprayers. However, more research is still needed to evaluate the potential negative effects of adulticide applications on non-target organisms
Iron Emission in the z=6.4 Quasar SDSS J114816.64+525150.3
We present near-infrared J and K-band spectra of the z = 6.4 quasar SDSS
J114816.64+525150.3 obtained with the NIRSPEC spectrograph at the Keck-II
telescope, covering the rest-frame spectral regions surrounding the C IV 1549
and Mg II 2800 emission lines. The iron emission blend at rest wavelength
2900-3000 A is clearly detected and its strength appears nearly
indistinguishable from that of typical quasars at lower redshifts. The Fe II /
Mg II ratio is also similar to values found for lower-redshift quasars,
demonstrating that there is no strong evolution in Fe/alpha broad-line emission
ratios even out to z=6.4. In the context of current models for iron enrichment
from Type Ia supernovae, this implies that the SN Ia progenitor stars formed at
z > 10. We apply the scaling relations of Vestergaard and of McLure & Jarvis to
estimate the black hole mass from the widths of the C IV and Mg II emission
lines and the ultraviolet continuum luminosity. The derived mass is in the
range (2-6)x10^9 solar masses, with an additional uncertainty of a factor of 3
due to the intrinsic scatter in the scaling relations. This result is in
agreement with the previous mass estimate of 3x10^9 solar masses by Willott,
McLure, & Jarvis, and supports their conclusion that the quasar is radiating
close to its Eddington luminosity.Comment: To appear in ApJ Letter
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