Student Leadership Conference Report 2010

This is the Student Leadership Conference Attendees Report from the retreat. This is the start of the I AM U-URI Unity in Difference group on campus

I AM U-URI Unity in Difference Mission Statement 2010

This post is the I AM U-URI Unity in Difference Mission Statement from 2010. The group became a student advisory committee for the President of the University of Rhode Island on the unique aspects of the student experience, as well as collaborate with other existing groups on issues concerning diversity at the University

Generalized Gravi-Electromagnetism

A self consistant and manifestly covariant theory for the dynamics of four charges (masses) (namely electric, magnetic, gravitational, Heavisidian) has been developed in simple, compact and consistent manner. Starting with an invariant Lagrangian density and its quaternionic representation, we have obtained the consistent field equation for the dynamics of four charges. It has been shown that the present reformulation reproduces the dynamics of individual charges (masses) in the absence of other charge (masses) as well as the generalized theory of dyons (gravito - dyons) in the absence gravito - dyons (dyons). key words: dyons, gravito - dyons, quaternion PACS NO: 14.80H

Chandra X-Ray Observatory Observations of the Globular Cluster M71

We observed the nearby, low-density globular cluster M71 (NGC 6838) with the Chandra X-ray Observatory to study its faint X-ray populations. Five X-ray sources were found inside the cluster core radius, including the known eclipsing binary millisecond pulsar (MSP) PSR J1953+1846A. The X-ray light curve of the source coincident with this MSP shows marginal evidence for periodicity at the binary period of 4.2 h. Its hard X-ray spectrum and luminosity resemble those of other eclipsing binary MSPs in 47 Tuc, suggesting a similar shock origin of the X-ray emission. A further 24 X-ray sources were found within the half-mass radius, reaching to a limiting luminosity of 1.5 10^30 erg/s (0.3-8 keV). From a radial distribution analysis, we find that 18+/-6 of these 29 sources are associated with M71, somewhat more than predicted, and that 11+/-6 are background sources, both galactic and extragalactic. M71 appears to have more X-ray sources between L_X=10^30--10^31 erg/s than expected by extrapolating from other studied clusters using either mass or collision frequency. We explore the spectra and variability of these sources, and describe the results of ground-based optical counterpart searches.Comment: 36 pages including 7 figures and 8 tables, accepted by The Astrophysical Journa

X-ray Binaries in the Ultrahigh Encounter Rate Globular Cluster NGC 6388

We report the results of a joint \chandra-\hst study of the X-ray binary population in the massive, high-density globular cluster NGC 6388. NGC 6388 has one of the highest predicted X-ray binary production rate of any Galactic cluster. We detected a large population of 61 \chandra sources within the half-mass radius with L$_X > 5 \times 10^{30}$ \ergs. From the X-ray colors, luminosities, (lack of) variability, and spectral fitting, we identify five as likely quiescent low-mass X-ray binaries. Due to the extremely crowded nature of the core of NGC 6388, finding optical identifications to \chandra sources is challenging. We have identified four blue, optically variable counterparts to spectrally hard X-ray sources, evidence that these are bright cataclysmic variables (CVs). One showed variability of 2 magnitudes in V, indicative of a dwarf nova eruption. One other likely CV is identified by its X-ray spectrum (partial covering with high $N_H$) and strong variability, making five likely CVs identified in this cluster. The relatively bright optical magnitudes of these sources put them in the same class as CV1 in M15 and the brightest CVs in 47 Tuc

Galactic-scale absorption outflow in the low-luminosity quasar IRAS F04250-5718: Hubble space telescope/cosmic origins spectrograph observations

We present absorption line analysis of the outflow in the quasar IRAS F04250?5718. Far-ultraviolet data from the Cosmic Origins Spectrograph on board the Hubble Space Telescope reveal intrinsic narrow absorption lines from high ionization ions (e.g., C iv, N v, and O vi) as well as low ionization ions (e.g., Cii and Si iii). We identify three kinematic components with central velocities ranging from ??50 to ??230 km s?1. Velocity-dependent, nonblack saturation is evident from the line profiles of the high ionization ions. From the non-detection of absorption from a metastable level of C ii, we are able to determine that the electron number density in the main component of the outflow is 30 cm?3. Photoionization analysis yields an ionization parameter log UH ? ?1.6 ± 0.2, which accounts for changes in the metallicity of the outflow and the shape of the incident spectrum. We also consider solutions with two ionization parameters. If the ionization structure of the outflow is due to photoionization by the active galactic nucleus, we determine that the distance to this component from the central source is 3 kpc. Due to the large distance determined for the main kinematic component, we discuss the possibility that this outflow is part of a galactic wind.We acknowledge support from NASA STScI grants GO 11686 and GO 12022 as well as NSF grant AST 0837880. We thank Pat Hall for insightful suggestions and discussions. J.I.G.-S. and C.B. acknowledge financial support from the Spanish Ministerio de Ciencia e Innovacion under project AYA2008-06311-C02-02

Evaluation of the Widal tube agglutination test for the diagnosis of typhoid fever among children admitted to a rural hdospital in Tanzania and a comparison with previous studies

BACKGROUND: The diagnosis of typhoid fever is confirmed by culture of Salmonella enterica serotype Typhi (S. typhi). However, a more rapid, simpler, and cheaper diagnostic method would be very useful especially in developing countries. The Widal test is widely used in Africa but little information exists about its reliability. METHODS: We assessed the performance of the Widal tube agglutination test among febrile hospitalized Tanzanian children. We calculated the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of various anti-TH and -TO titers using culture-confirmed typhoid fever cases as the "true positives" and all other febrile children with blood culture negative for S. typhi as the "true negatives." RESULTS: We found that 16 (1%) of 1,680 children had culture-proven typhoid fever. A single anti-TH titer of 1:80 and higher was the optimal indicator of typhoid fever. This had a sensitivity of 75%, specificity of 98%, NPV of 100%, but PPV was only 26%. We compared our main findings with those from previous studies. CONCLUSION: Among febrile hospitalized Tanzanian children with a low prevalence of typhoid fever, a Widal titer of > or = 1:80 performed well in terms of sensitivity, specificity, and NPV. However a test with improved PPV that is similarly easy to apply and cost-efficient is desirable

Invasive Salmonellosis among Children Admitted to a Rural Tanzanian Hospital and a Comparison with Previous Studies

BACKGROUND: The importance of invasive salmonellosis in African children is well recognized but there is inadequate information on these infections. We conducted a fever surveillance study in a Tanzanian rural hospital to estimate the case fraction of invasive salmonellosis among pediatric admissions, examine associations with common co-morbidities and describe its clinical features. We compared our main findings with those from previous studies among children in sub-Saharan Africa. METHODOLOGY/PRINCIPAL FINDINGS: From 1 March 2008 to 28 Feb 2009, 1,502 children were enrolled into the study. We collected clinical information and blood for point of care tests, culture, and diagnosis of malaria and HIV. We analyzed the clinical features on admission and outcome by laboratory-confirmed diagnosis. Pathogenic bacteria were isolated from the blood of 156 (10%) children, of which 14 (9%) were S. typhi, 45 (29%) were NTS and 97 (62%) were other pathogenic bacteria. Invasive salmonellosis accounted for 59/156 (38%) bacteremic children. Children with typhoid fever were significantly older and presented with a longer duration of fever. NTS infections were significantly associated with prior antimalarial treatment, malarial complications and with a high risk for death. CONCLUSIONS/SIGNIFICANCE: Invasive salmonellosis, particularly NTS infection, is an important cause of febrile disease among hospitalized children in our rural Tanzanian setting. Previous studies showed considerable variation in the case fraction of S. typhi and NTS infections. Certain suggestive clinical features (such as older age and long duration of fever for typhoid whereas concomitant malaria, anemia, jaundice and hypoglycemia for NTS infection) may be used to distinguish invasive salmonellosis from other severe febrile illness

Functional carbohydrate binding modules identified in evolved Dits from siphophages infecting various Gram-positive bacteria

With increasing numbers of 3D structures of bacteriophage components, combined with powerful in silico predictive tools, it has become possible to decipher the structural assembly and associated functionality of phage adhesion devices. Recently, decorations have been reported in the tail and neck passage structures of members of the so‐called 936 group of lactococcal siphophages. In the current report, using bioinformatic analysis we identified a conserved carbohydrate binding module (CBM) among many of the virion baseplate Dit components, in addition to the CBM present in the ‘classical’ receptor binding proteins (RBPs). We observed that, within these so‐called ‘evolved’ Dit proteins, the identified CBMs have structurally conserved folds, yet can be grouped into four distinct classes. We expressed such modules in fusion with GFP, and demonstrated their binding capability to their specific host using fluorescent binding assays with confocal microscopy. We detected evolved Dits in several phages infecting various Gram‐positive bacterial species, including mycobacteria. The omnipresence of CBM domains in Siphophages indicates their auxiliary role in infection, as they can assist in the specific recognition of and attachment to their host, thus ensuring a highly efficient and specific phage‐host adhesion process as a prelude to DNA injection