Thermal stability of cold clouds in galaxy halos

We consider the thermal properties of cold, dense clouds of molecular hydrogen and atomic helium. For cloud masses below 10^-1.7 Msun, the internal pressure is sufficient to permit the existence of particles of solid or liquid hydrogen at temperatures above the microwave background temperature. Optically thin thermal continuum emission by these particles can balance cosmic-ray heating of the cloud, leading to equilibria which are thermally stable even though the heating rate is independent of cloud temperature. For the Galaxy, the known heating rate in the disk sets a minimum mass of order 10^-6 Msun necessary for survival. Clouds of this type may in principle comprise most of the dark matter in the Galactic halo. However, we caution that the equilibria do not exist at redshifts z > 1 when the temperature of the microwave background was substantially larger than its current value; the formation and survival of such clouds to the present epoch therefore remain open questions.Comment: 5 pp incl 2 figs, LaTeX, emulateapj.sty; ApJ Letters in press. Significant revisions, results qualitatively unchange

Late thoracic pseudo-aneurysm causing collapse of vascular prostheses

The outcome of patients with thoracic vascular prostheses is usually uneventful. We report two cases of collapse of thoracic vascular prostheses which occurred ten and forty years, respectively, after the implantation. The diagnoses were obtained preoperatively by CT-scan or NMR and angiography. Both patients were successfully treated with prosthetic replacement by an open approach

Host range evaluation and morphological characterization of Pseudoperonospora cubensis, the causal agent of cucurbit downy mildew in Malaysia

A total of 29 isolates of Pseudoperonospora cubensis were collected from various cucurbit farms in West Malaysia. Sporangia of 13 isolates had the ability to germinate at 14°C and were used for host range (pathotype) study using leaf disc assay on a set of twelve cucurbit cultivars. Twelve different pathotypes of P. cubensis were determined and this demonstrated that P. cubensis isolates from cucurbit farms in West Malaysia are highly variable. Based on the host range study, majority of P. cubensis isolates were categorized into medium and high pathogenicity groupings and this fact shows the potential of this pathogen in invading cucurbit fields in the tropical regions. However, the pathotypes could not be differentiated based on morphological characterization of the sporangia and sporangiophores. Therefore, molecular characterization of the 13 isolates of P. cubensis will be useful to study the relationships among them.Key word: Oomycete, differential hosts, compatibility rating, pathogenic variation, sporangial germination

Epidemiological overview of Hodgkin lymphoma across the Mediterranean Basin

The epidemiology of Hodgkin lymphoma (HL) has always been a source of fascination to researchers due to its heterogeneous characteristics of presentation. HL is an uncommon neoplasm of B-cell origin with an incidence that varies significantly by age, sex, ethnicity, geographic location and socioeconomic status. This complex pattern was also found to be replicated among Mediterranean basin populations. HL incidence rates progressively decreased from industrialized European countries such as France (ASR=2.61) and Italy (ASR=2.39) to less developed nations such as Albania (ASR=1.34) and Bosnia Herzegovina (ASR=1.1). Regarding HL mortality we have found that countries with the lowest incidence rates show the highest number of deaths from this cancer and viceversa. Finally, a wide gap in terms of survival was showed across the Mediterranean basin with survival rates ranged from 82.3% and 85.1% among Italian men and women, to 53.3 % and 59.3% among Libyan men and women, respectively. Factors such as the degree of socio-economic development, the exposure to risk factors westernization-related, the availability of diagnostic practices along with different genetic susceptibilities to HL may explain its variation across Mediterranean countries. Furthermore, the lack of health resources decisively contribute to the poor prognosis recorded in less developed region. In the future, the introduction of appropriate and accessible treatment facilities along with an adequate number of clinical specialists in the treatment of HL and other cancers are warranted in order to improve the outcomes of affected patients and treat a largely curable type of cancer in disadvantaged regions

Kaluza-Klein Dark Matter and Galactic Antiprotons

Extra dimensions offer new ways to address long-standing problems in beyond the standard model particle physics. In some classes of extra-dimensional models, the lightest Kaluza-Klein particle is a viable dark matter candidate. In this work, we study indirect detection of Kaluza-Klein dark matter via its annihilation into antiprotons. We use a sophisticated galactic cosmic ray diffusion model whose parameters are fully constrained by an extensive set of experimental data. We discuss how fluxes of cosmic antiprotons can be used to exclude low Kaluza-Klein masses.Comment: 14 pages, 7 figures, 3 table

Molecular identification and phylogenetic analysis of Pseudoperonospora cubensis isolates in Peninsula Malaysia

Thirteen isolates of Pseudoperonospora cubensis, the causal agent of downy mildew, were collected from cucurbit fields in five states of the western part of Peninsular Malaysia during its growing season between November 2008 and March 2009. The host range of these isolates was determined previously using leaf disc assay and the results indicated that there were 12 pathotypes among these isolates. The objective of this study was to analyze the 13 isolates for phylogenetic relationship using internal transcribed spacers (ITS) of ribosomal DNA (rDNA) and mitochondrial COX-II regions. A high sequence similarity among the 13 isolates and similar sequences from GenBank were detected in ITS (>99%) and COX-II (>98%) regions. Phylogenetic analysis of the 13 isolates based on Minimum Evolution method performed on ITS and COX-II regions revealed five and three groupings, respectively. However, no relationship was found between the phylogenetic groupings using both genes and pathotypes in this study

Is the Large Magellanic Cloud a Large Microlensing Cloud?

An expression is provided for the self-lensing optical depth of the thin LMC disk surrounded by a shroud of stars at larger scale heights. The formula is written in terms of the vertical velocity dispersion of the thin disk population. If tidal forcing causes 1-5 % of the disk mass to have a height larger than 6 kpc and 10-15 % to have a height above 3 kpc, then the self-lensing optical depth of the LMC is $0.7 - 1.9 \times 10^{-7}$, which is within the observational uncertainties. The shroud may be composed of bright stars provided they are not in stellar hydrodynamical equilibrium. Alternatively, the shroud may be built from low mass stars or compact objects, though then the self-lensing optical depths are overestimates of the true optical depth by a factor of roughly 3. The distributions of timescales of the events and their spatial variation across the face of the LMC disk offer possibilities of identifying the dominant lens population. In propitious circumstances, an experiment lifetime of less than 5 years is sufficient to decide between the competing claims of Milky Way halos and LMC lenses. However, LMC disks can sometimes mimic the microlensing properties of Galactic halos for many years and then decades of survey work are needed. In this case observations of parallax or binary caustic events offer the best hope for current experiments to deduce the lens population. The difficult models to distinguish are Milky Way halos in which the lens fraction is low (< 10 %) and fattened LMC disks composed of lenses with a typical mass of low luminosity stars or greater. A next-generation wide-area microlensing survey, such as the proposed ``SuperMACHO'' experiment, will be able to distinguish even these difficult models with just a year or two of data.Comment: 25 pages, 4 figures, The Astrophysical Journal (in press