Self-Dual Strings and N=2 Supersymmetric Field Theory

We show how the Riemann surface $\Sigma$ of $N=2$ Yang-Mills field theory arises in type II string compactifications on Calabi-Yau threefolds. The relevant local geometry is given by fibrations of ALE spaces. The $3$-branes that give rise to BPS multiplets in the string descend to self-dual strings on the Riemann surface, with tension determined by a canonically fixed Seiberg-Witten differential $\lambda$. This gives, effectively, a dual formulation of Yang-Mills theory in which gauge bosons and monopoles are treated on equal footing, and represents the rigid analog of type II-heterotic string duality. The existence of BPS states is essentially reduced to a geodesic problem on the Riemann surface with metric $|\lambda|^2$. This allows us, in particular, to easily determine the spectrum of {\it stable} BPS states in field theory. Moreover, we identify the six-dimensional space \IR^4\times \Sigma as the world-volume of a five-brane and show that BPS states correspond to two-branes ending on this five-brane.Comment: harvmac, 22p, uses epsf, with 3 .eps figures (references added plus other minor corrections

Unique Pattern of Enzootic Primate Viruses in Gibraltar Macaques

Because Gibraltar's macaques (Macaca sylvanus) have frequent contact with humans, we assayed 79 macaques for antibodies to enzootic primate viruses. All macaques were seronegative for herpesvirus B, simian T-cell lymphotropic virus, simian retrovirus, simian immunodeficiency virus, and rhesus cytomegalovirus. Seroprevalence of simian foamy virus reached 88% among adult animals

Cosmic-ray-induced ionization in molecular clouds adjacent to supernova remnants - Tracing the hadronic origin of GeV gamma radiation

Energetic gamma rays (GeV to TeV photon energy) have been detected toward several supernova remnants (SNR) associated with molecular clouds. If the gamma rays are produced mainly by hadronic processes rather than leptonic processes like bremsstrahlung, then the flux of energetic cosmic ray (CR) nuclei (>1 GeV) required to produce the gamma rays can be inferred at the site where the particles are accelerated in SNR shocks. It is of great interest to understand the acceleration of the CR of lower energy (<1 GeV) accompanying the energetic component. These particles of lower energy are most effective in ionizing interstellar gas, leaving an observable imprint on the interstellar ion chemistry. A correlation of energetic gamma radiation with enhanced interstellar ionization can thus support the hadronic origin of the gamma rays and constrain the acceleration of ionizing CR in SNR. We propose a method to test the hadronic origin of GeV gamma rays from SNR associated with a molecular cloud. We use observational gamma ray data for each of these SNR known, modeling the observations to obtain the underlying proton spectrum assuming that the gamma rays are produced by pion decay. Assuming that the acceleration mechanism does not only produce high energy protons, but also low energy protons, this proton spectrum at the source is then used to calculate the ionization rate of the molecular cloud. Ionized molecular hydrogen triggers a chemical network forming molecular ions. The relaxation of these ions results in characteristic line emission, which can be predicted. We show that the ionization rate for at least two objects is more than an order of magnitude above Galactic average for molecular clouds, hinting at an enhanced formation rate of molecular ions. There will be interesting opportunities to measure crucial molecular ions in the infrared and submillimeter-wave parts of the spectrum.Comment: published in Astronomy and Astrophysics, 13 pages, 19 figure

Tachyon Condensation on the Elliptic Curve

We use the framework of matrix factorizations to study topological B-type D-branes on the cubic curve. Specifically, we elucidate how the brane RR charges are encoded in the matrix factors, by analyzing their structure in terms of sections of vector bundles in conjunction with equivariant R-symmetry. One particular advantage of matrix factorizations is that explicit moduli dependence is built in, thus giving us full control over the open-string moduli space. It allows one to study phenomena like discontinuous jumps of the cohomology over the moduli space, as well as formation of bound states at threshold. One interesting aspect is that certain gauge symmetries inherent to the matrix formulation lead to a non-trivial global structure of the moduli space. We also investigate topological tachyon condensation, which enables us to construct, in a systematic fashion, higher-dimensional matrix factorizations out of smaller ones; this amounts to obtaining branes with higher RR charges as composites of ones with minimal charges. As an application, we explicitly construct all rank-two matrix factorizations.Comment: 69p, 6 figs, harvmac; v2: minor change

Population dynamics of rhesus macaques and associated foamy virus in Bangladesh.

Foamy viruses are complex retroviruses that have been shown to be transmitted from nonhuman primates to humans. In Bangladesh, infection with simian foamy virus (SFV) is ubiquitous among rhesus macaques, which come into contact with humans in diverse locations and contexts throughout the country. We analyzed microsatellite DNA from 126 macaques at six sites in Bangladesh in order to characterize geographic patterns of macaque population structure. We also included in this study 38 macaques owned by nomadic people who train them to perform for audiences. PCR was used to analyze a portion of the proviral gag gene from all SFV-positive macaques, and multiple clones were sequenced. Phylogenetic analysis was used to infer long-term patterns of viral transmission. Analyses of SFV gag gene sequences indicated that macaque populations from different areas harbor genetically distinct strains of SFV, suggesting that geographic features such as forest cover play a role in determining the dispersal of macaques and SFV. We also found evidence suggesting that humans traveling the region with performing macaques likely play a role in the translocation of macaques and SFV. Our studies found that individual animals can harbor more than one strain of SFV and that presence of more than one SFV strain is more common among older animals. Some macaques are infected with SFV that appears to be recombinant. These findings paint a more detailed picture of how geographic and sociocultural factors influence the spectrum of simian-borne retroviruses

Evidence of Natural Bluetongue Virus Infection among African Carnivores

Bluetongue is an International Office of Epizootics List A disease described as the century\u27s most economically devastating affliction of sheep. Bluetongue (BLU) viruses were thought to infect only ruminants, shrews, and some rodents, but recently, inadvertent administration of BLU virus-contaminated vaccine resulted in mortality and abortion among domestic dogs. We present evidence of natural BLU virus infection among African carnivores that dramatically widens the spectrum of susceptible hosts. We hypothesize that such infection occurred after ingestion of meat and organs from BLU virus infected prey species. The effect of BLU virus on endangered carnivores such as the cheetah and African wild dog requires urgent investigation. Also, the role of carnivores in the epizootiology of this disease needs elucidation

Spectral flow and boundary string field theory for angled D-branes

D-branes intersecting at an arbitrary fixed angle generically constitute a configuration unstable toward recombination. The reconnection of the branes nucleates at the intersection point and involves a generalization of the process of brane decay of interest to non-perturbative string dynamics as well as cosmology. After reviewing the string spectrum of systems of angled branes, we show that worldsheet twist superfields may be used in the context of Boundary Superstring Field Theory to describe the dynamics. Changing the angle between the branes is seen from the worldsheet as spectral flow with boundary insertions flowing from bosonic to fermionic operators. We calculate the complete tachyon potential and the low energy effective action as a function of angle and find an expression that interpolates between the brane-antibrane and the Dirac-Born-Infeld actions. The potential captures the mechanism of D-brane recombination and provides for interesting new physics for tachyon decay.Comment: 32 pages, 9 figures; v2 references added; v3 discussion clarifie

Black-hole entropy from supergravity superstrata states

This work of JdB was supported in part by the Foundation of Fundamental Research on Matter (FOM) and by an NWO Spinoza grant. The work of MS was supported in part by Grant-in-Aid for Young Scientists (B) 24740159 from the Japan Society for the Promotion of Science (JSPS)

Cross-Species Transmission of a Novel Adenovirus Associated with a Fulminant Pneumonia Outbreak in a New World Monkey Colony

Adenoviruses are DNA viruses that naturally infect many vertebrates, including humans and monkeys, and cause a wide range of clinical illnesses in humans. Infection from individual strains has conventionally been thought to be species-specific. Here we applied the Virochip, a pan-viral microarray, to identify a novel adenovirus (TMAdV, titi monkey adenovirus) as the cause of a deadly outbreak in a closed colony of New World monkeys (titi monkeys; Callicebus cupreus) at the California National Primate Research Center (CNPRC). Among 65 titi monkeys housed in a building, 23 (34%) developed upper respiratory symptoms that progressed to fulminant pneumonia and hepatitis, and 19 of 23 monkeys, or 83% of those infected, died or were humanely euthanized. Whole-genome sequencing of TMAdV revealed that this adenovirus is a new species and highly divergent, sharing <57% pairwise nucleotide identity with other adenoviruses. Cultivation of TMAdV was successful in a human A549 lung adenocarcinoma cell line, but not in primary or established monkey kidney cells. At the onset of the outbreak, the researcher in closest contact with the monkeys developed an acute respiratory illness, with symptoms persisting for 4 weeks, and had a convalescent serum sample seropositive for TMAdV. A clinically ill family member, despite having no contact with the CNPRC, also tested positive, and screening of a set of 81 random adult blood donors from the Western United States detected TMAdV-specific neutralizing antibodies in 2 individuals (2/81, or 2.5%). These findings raise the possibility of zoonotic infection by TMAdV and human-to-human transmission of the virus in the population. Given the unusually high case fatality rate from the outbreak (83%), it is unlikely that titi monkeys are the native host species for TMAdV, and the natural reservoir of the virus is still unknown. The discovery of TMAdV, a novel adenovirus with the capacity to infect both monkeys and humans, suggests that adenoviruses should be monitored closely as potential causes of cross-species outbreaks