The Discovery of Extended Thermal X-ray Emission from PKS 2152-699: Evidence for a `Jet-cloud' Interaction

A Chandra ACIS-S observation of PKS 2152-699 reveals thermal emission from a diffuse region around the core and a hotspot located 10" northeast from the core. This is the first detection of thermal X-ray radiation on kiloparsec scales from an extragalactic radio source. Two other hotspots located 47" north-northeast and 26" southwest from the core were also detected. Using a Raymond-Smith model, the first hotspot can be characterized with a thermal plasma temperature of 2.6$\times10^6$ K and an electron number density of 0.17 cm$^{-3}$. These values correspond to a cooling time of about 1.6$\times10^7$ yr. In addition, an emission line from the hotspot, possibly Fe xxv, was detected at rest wavelength 10.04\AA. The thermal X-ray emission from the first hotspot is offset from the radio emission but is coincident with optical filaments detected with broadband filters of HST/WFPC2. The best explanation for the X-ray, radio, and optical emission is that of a `jet-cloud' interaction. The diffuse emission around the nucleus of PKS 2152-699 can be modeled as a thermal plasma with a temperature of 1.2$\times10^7$ K and a luminosity of 1.8$\times10^{41}$ erg s$^{-1}$. This emission appears to be asymmetric with a small extension toward Hotspot A, similar to a jet. An optical hotspot (EELR) is seen less than an arcsecond away from this extension in the direction of the core. This indicates that the extension may be caused by the jet interacting with an inner ISM cloud, but entrainment of hot gas is unavoidable. Future observations are discussed.Comment: To appear in the Astrophysical Journal 21 pages, 5 Postscript figures, 1 table, AASTeX v. 5.

Agents in adversarial domains - modelling environments in parallel

We present a model of an environment to evaluate the behavior of an agent trying to hide from a pursuer is presented. The model computes the direction and the amount of protection provided by the environment. The computational complexity of this problem is improved by using a parallel implementation of this algorithm.<br /

Foci of Schistosomiasis mekongi, Northern Cambodia: II. Distribution of infection and morbidity.

In the province of Kracheh, in Northern Cambodia, a baseline epidemiological survey on Schistosoma mekongi was conducted along the Mekong River between December 1994 and April 1995. The results of household surveys of highly affected villages of the East and the West bank of the river and of school surveys in 20 primary schools are presented. In household surveys 1396 people were examined. An overall prevalence of infection of 49.3% was detected by a single stool examination with the Kato-Katz technique. The overall intensity of infection was 118.2 eggs per gram of stool (epg). There was no difference between the population of the east and west shore of the Mekong for prevalence (P = 0.3) or intensity (P = 0.9) of infection. Severe morbidity was very frequent. Hepatomegaly of the left lobe was detected in 48.7% of the population. Splenomegaly was seen in 26.8% of the study participants. Visible diverted circulation was found in 7.2% of the population, and ascites in 0.1%. Significantly more hepatomegaly (P = 0.001), splenomegaly (P = 0. 001) and patients with diverted circulation (P = 0.001) were present on the west bank of the Mekong. The age group of 10-14 years was most affected. The prevalence of infection in this group was 71.8% and 71.9% in the population of the West and East of the Mekong, respectively. The intensity of infection was 172.4 and 194.2 epg on the West and the East bank, respectively. In the peak age group hepatomegaly reached a prevalence of 88.1% on the west and 82.8% on the east bank. In the 20 schools 2391 children aged 6-16 years were examined. The overall prevalence of infection was 40.0%, ranging from 7.7% to 72.9% per school. The overalls mean intensity of infection was 110.1 epg (range by school: 26.7-187.5 epg). Both prevalence (P = 0.001) and intensity of infection (P = 0.001) were significantly higher in schools on the east side of the Mekong. Hepatomegaly (55.2%), splenomegaly (23.6%), diverted circulation (4. 1%), ascites (0.5%), reported blood (26.7%) and mucus (24.3%) were very frequent. Hepatomegaly (P = 0.001), splenomegaly (P = 0.001), diverted circulation (P = 0.001) and blood in stool (P = 0.001) were significantly more frequent in schools of the east side of the Mekong. Boys suffered more frequently from splenomegaly (P = 0.05), ascites (P = 0.05) and bloody stools (P = 0.004) than girls. No difference in sex was found for the prevalence and intensity of infection and prevalence of hepatomegaly. On the school level prevalence and intensity of infection were highly associated (r = 0. 93, P = 0.0001). The intensity of infection was significantly associated only with the prevalence of hepatomegaly (r = 0.44, P = 0. 05) and blood in stool (r = 0.40, P = 0.02). This comprehensive epidemiological study documents for the first time the public health importance of schistosomiasis mekongi in the Province of Kracheh, Northern Cambodia and points at key epidemiological features of this schistosome species, in particular the high level of morbidity associated with infection

Coastal risk assessment framework guidance document

The Resilience-Increasing Strategies for Coasts – Toolkit (RISC-KIT) FP7 EU project (2013-2017) aims to produce a set of three innovative and EU-coherent open-source and open-access methods, tools and management approaches (the RISC-KIT) in support of coastal managers, decision-makers and policy makers to reduce risk and increase resilience to low-frequency, high impact hydro-meteorological events. The Coastal Risk Assessment Framework (CRAF) is the first element of the risk assessment suite applied at a regional scale and permits a comprehensive and systematic approach to undertaking risk assessment at a variety of levels of detail. In particular, the approach reveals potential hotspots along the coasts. Hotspots are defined in the Toolkit as specific locations where high-resolution modelling and risk assessment are required to assess the coastal risk and to design and compare disaster risk reduction measures. As such, hotspots, or groups of hotspots, should be indicative of those areas where risk is highest. To do so the CRAF consists of a 2-phase approach, Phase 1 is a coastal-index approach to identifying potential hotspots, whereas Phase 2 utilises a suite of more complex modelling processes to rank these hotpots. The coastal INtegrated DisRuption Assessment model (INDRA) has specifically been developed as an open-source and open-access model for this purpose. This document provides guidance to CRAF users on both approaches, as well as explanations on the proposed methodologies. The CRAF is a prototype and will be trialled on the RISC-KIT case studies (WP5). Limitations in its application, the potential for a full application and the needs for further development will be discussed in Deliverable 5.1

A Direct Interaction between IP3 Receptors and Myosin II Regulates IP3 Signaling in C. elegans

AbstractMolecular and physiological studies of cells implicate interactions between the cytoskeleton and the intracellular calcium signalling machinery as an important mechanism for the regulation of calcium signalling [1–11]. However, little is known about the functions of such mechanisms in animals. A key component of the calcium signalling network is the intracellular release of calcium in response to the production of the second messenger inositol 1,4,5-trisphosphate (IP3), mediated by the IP3 receptor (IP3R) [12–14]. We show that C. elegans IP3Rs, encoded by the gene itr-1, interact directly with myosin II. The interactions between two myosin proteins, UNC-54 and MYO-1, and ITR-1 were identified in a yeast two-hybrid screen and subsequently confirmed in vivo and in vitro. We defined the interaction sites on both the IP3R and MYO-1. To test the effect of disrupting the interaction in vivo we overexpressed interacting fragments of both proteins in C. elegans. This decreased the animal's ability to upregulate pharyngeal pumping in response to food. This is a known IP3-mediated process [15]. Other IP3-mediated processes, e.g., defecation [16], were unaffected. Thus it appears that interactions between IP3Rs and myosin are required for maintaining the specificity of IP3 signalling in C. elegans and probably more generally

Fluctuation-Facilitated Charge Migration along DNA

We propose a model Hamiltonian for charge transfer along the DNA double helix with temperature driven fluctuations in the base pair positions acting as the rate limiting factor for charge transfer between neighboring base pairs. We compare the predictions of the model with the recent work of J.K. Barton and A.H. Zewail (Proc.Natl.Acad.Sci.USA, {\bf 96}, 6014 (1999)) on the unusual two-stage charge transfer of DNA.Comment: 4 pages, 2 figure

Incremental Contributions of FbaA and Other Impetigo-Associated Surface Proteins to Fitness and Virulence of a Classical Group A Streptococcal Skin Strain

Group A streptococci (GAS) are highly prevalent human pathogens whose primary ecological niche is the superficial epithelial layers of the throat and/or skin. Many GAS strains having a strong tendency to cause pharyngitis are distinct from strains that tend to cause impetigo; thus, genetic differences between them may confer host tissue-specific virulence. In this study, the FbaA surface protein gene is found to be present in most skin specialist strains, but largely absent from a genetically-related subset of pharyngitis isolates. Using an DeltafbaA mutant constructed in the impetigo strain Alab49, loss of FbaA resulted in a slight but significant decrease in GAS fitness in a humanized mouse model for impetigo; the DeltafbaA mutant also exhibited decreased survival in whole human blood due to phagocytosis. Using assays with highly sensitive outcome measures, Alab49DeltafbaA was compared to other isogenic mutants lacking virulence genes known to be disproportionately associated with classical skin strains. FbaA and PAM (i.e., M53 protein) have additive effects in promoting GAS survival in whole blood. The pilus adhesin tip protein Cpa promotes Alab49 survival in whole blood, and appears to fully account for the antiphagocytic effect attributable to pili. That numerous skin strain-associated virulence factors make slight but significant contributions to virulence underscores the incremental contributions to fitness of individual surface protein genes and the multifactorial nature of GAS-host interactions