120 research outputs found
UWISH2 -- The UKIRT Widefield Infrared Survey for H2
We present the goals and preliminary results of an unbiased, near-infrared,
narrow-band imaging survey of the First Galactic Quadrant (10deg<l<65deg ;
-1.3deg<b<+1.3deg). This area includes most of the Giant Molecular Clouds and
massive star forming regions in the northern hemisphere. The survey is centred
on the 1-0S(1) ro-vibrational line of H2, a proven tracer of hot, dense
molecular gas in star-forming regions, around evolved stars, and in supernova
remnants. The observations complement existing and upcoming photometric surveys
(Spitzer-GLIMPSE, UKIDSS-GPS, JCMT-JPS, AKARI, Herschel Hi-GAL, etc.), though
we probe a dynamically active component of star formation not covered by these
broad-band surveys. Our narrow-band survey is currently more than 60% complete.
The median seeing in our images is 0.73arcsec. The images have a 5sigma
detection limit of point sources of K=18mag and the surface brightness limit is
10^-19Wm^-2arcsec^-2 when averaged over our typical seeing. Jets and outflows
from both low and high mass Young Stellar Objects are revealed, as are new
Planetary Nebulae and - via a comparison with earlier K-band observations
acquired as part of the UKIDSS GPS - numerous variable stars. With their
superior spatial resolution, the UWISH2 data also have the potential to reveal
the true nature of many of the Extended Green Objects found in the GLIMPSE
survey.Comment: 14pages, 8figures, 2tables, accepted for publication by MNRAS, a
version with higher resolution figures can be found at
http://astro.kent.ac.uk/~df
Radio emission from Supernova Remnants
The explosion of a supernova releases almost instantaneously about 10^51 ergs
of mechanic energy, changing irreversibly the physical and chemical properties
of large regions in the galaxies. The stellar ejecta, the nebula resulting from
the powerful shock waves, and sometimes a compact stellar remnant, constitute a
supernova remnant (SNR). They can radiate their energy across the whole
electromagnetic spectrum, but the great majority are radio sources. Almost 70
years after the first detection of radio emission coming from a SNR, great
progress has been achieved in the comprehension of their physical
characteristics and evolution. We review the present knowledge of different
aspects of radio remnants, focusing on sources of the Milky Way and the
Magellanic Clouds, where the SNRs can be spatially resolved. We present a brief
overview of theoretical background, analyze morphology and polarization
properties, and review and critical discuss different methods applied to
determine the radio spectrum and distances. The consequences of the interaction
between the SNR shocks and the surrounding medium are examined, including the
question of whether SNRs can trigger the formation of new stars. Cases of
multispectral comparison are presented. A section is devoted to reviewing
recent results of radio SNRs in the Magellanic Clouds, with particular emphasis
on the radio properties of SN 1987A, an ideal laboratory to investigate
dynamical evolution of an SNR in near real time. The review concludes with a
summary of issues on radio SNRs that deserve further study, and analyzing the
prospects for future research with the latest generation radio telescopes.Comment: Revised version. 48 pages, 15 figure
New high-resolution radio observations of the SNR CTB 80
We report new high resolution and high sensitivity radio observations of the
extended supernova remnant (SNR) CTB 80 (G69.0+2.7) at 240 MHz, 324 MHz, 618
MHz, and 1380 MHz. The imaging of CTB 80 at 240 MHz and 618 MHz was performed
using the Giant Metrewave Radio Telescope (GMRT) in India. The observations at
324 MHz and 1380 MHz were obtained using the Very Large Array (VLA, NRAO) in
its C and D configurations. The new radio images reveal faint extensions for
the asymmetric arms of CTB 80. The arms are irregular with filaments and clumps
of size 1' (or 0.6 pc at a distance of 2 kpc). The radio image at 1380 MHz is
compared with IR and optical emission. The correspondence IR/radio is excellent
along the N arm of CTB 80. Ionized gas observed in the [SII] line perfectly
matches the W and N edges of CTB 80. The central nebula associated with the
pulsar PSR B1951+32 was investigated with an angular resolution of 10" x 6".
The new radio image obtained at 618 MHz shows with superb detail structures in
the 8' x 4' E-W ``plateau'' nebula that hosts the pulsar on its western
extreme. A twisted filament, about 6' in extent (~3.5 pc), trails behind the
pulsar in an approximate W-E direction. In the bright ``core'' nebula (size
\~45"), located to the W of the plateau, the images show a distortion in the
morphology towards the W; this feature corresponds to the direction in which
the pulsar escapes from the SNR with a velocity of ~240 km/s. Based on the new
observations, the energetics of the SNR and of the PWN are investigated.Comment: 11 pages, Latex, 6 eps figures, To appear in AJ Vol 126., No. 5,
November 200
Genome-wide association analyses identify new Brugada syndrome risk loci and highlight a new mechanism of sodium channel regulation in disease susceptibility
Brugada syndrome (BrS) is a cardiac arrhythmia disorder associated with sudden death in young adults. With the exception of SCN5A, encoding the cardiac sodium channel NaV1.5, susceptibility genes remain largely unknown. Here we performed a genome-wide association meta-analysis comprising 2,820 unrelated cases with BrS and 10,001 controls, and identified 21 association signals at 12 loci (10 new). Single nucleotide polymorphism (SNP)-heritability estimates indicate a strong polygenic influence. Polygenic risk score analyses based on the 21 susceptibility variants demonstrate varying cumulative contribution of common risk alleles among different patient subgroups, as well as genetic associations with cardiac electrical traits and disorders in the general population. The predominance of cardiac transcription factor loci indicates that transcriptional regulation is a key feature of BrS pathogenesis. Furthermore, functional studies conducted on MAPRE2, encoding the microtubule plus-end binding protein EB2, point to microtubule-related trafficking effects on NaV1.5 expression as a new underlying molecular mechanism. Taken together, these findings broaden our understanding of the genetic architecture of BrS and provide new insights into its molecular underpinnings
Analysis of LhcSR3, a Protein Essential for Feedback De-Excitation in the Green Alga Chlamydomonas reinhardtii
To prevent photodamage by excess light, plants use different proteins to sense pH changes and to dissipate excited energy states. In green microalgae, however, the LhcSR3 gene product is able to perform both pH sensing and energy quenching functions
Prediction of Peptide Reactivity with Human IVIg through a Knowledge-Based Approach
The prediction of antibody-protein (antigen) interactions is very difficult due to the huge variability that characterizes the structure of the antibodies. The region of the antigen bound to the antibodies is called epitope. Experimental data indicate that many antibodies react with a panel of distinct epitopes (positive reaction). The Challenge 1 of DREAM5 aims at understanding whether there exists rules for predicting the reactivity of a peptide/epitope, i.e., its capability to bind to human antibodies. DREAM 5 provided a training set of peptides with experimentally identified high and low reactivities to human antibodies. On the basis of this training set, the participants to the challenge were asked to develop a predictive model of reactivity. A test set was then provided to evaluate the performance of the model implemented so far
CCL28 Induces Mucosal Homing of HIV-1-Specific IgA-Secreting Plasma Cells in Mice Immunized with HIV-1 Virus-Like Particles
Mucosae-associated epithelial chemokine (MEC or CCL28) binds to CCR3 and CCR10 and recruits IgA-secreting plasma cells (IgA-ASCs) in the mucosal lamina propria. The ability of this chemokine to enhance migration of IgA-ASCs to mucosal sites was assessed in a mouse immunization model using HIV-1IIIB Virus-like particles (VLPs). Mice receiving either HIV-1IIIB VLPs alone, CCL28 alone, or the irrelevant CCL19 chemokine were used as controls. Results showed a significantly increased CCR3 and CCR10 expression on CD19+ splenocytes of HIV-1IIIB VPL-CCL28-treated mice. HIV-1 Env-specific IFN-γ, IL-4 and IL-5 production, total IgA, anti-Env IgA as well as gastro-intestinal mucosal IgA-secreting plasma cells were also significantly augmented in these mice. Notably, sera and vaginal secretions from HIV-1IIIB VLP-CCL28-treated mice exhibited an enhanced neutralizing activity against both a HIV-1/B-subtype laboratory strain and a heterologous HIV-1/C-subtype primary isolate. These data suggest that CCL28 could be useful in enhancing the IgA immune response that will likely play a pivotal role in prophylactic HIV vaccines
Recommended from our members
Standardized assessment of evidence supporting the adoption of mobile health solutions: A Clinical Consensus Statement of the ESC Regulatory Affairs Committee
Mobile health (mHealth) solutions have the potential to improve self-management and clinical care. For successful integration into routine clinical practice, healthcare professionals (HCPs) need accepted criteria helping the mHealth solutions’ selection, while patients require transparency to trust their use. Information about their evidence, safety and security may be hard to obtain and consensus is lacking on the level of required evidence. The new Medical Device Regulation is more stringent than its predecessor, yet its scope does not span all intended uses and several difficulties remain. The European Society of Cardiology Regulatory Affairs Committee set up a Task Force to explore existing assessment frameworks and clinical and cost-effectiveness evidence. This knowledge was used to propose criteria with which HCPs could evaluate mHealth solutions spanning diagnostic support, therapeutics, remote follow-up and education, specifically for cardiac rhythm management, heart failure and preventive cardiology. While curated national libraries of health apps may be helpful, their requirements and rigour in initial and follow-up assessments may vary significantly. The recently developed CEN-ISO/TS 82304-2 health app quality assessment framework has the potential to address this issue and to become a widely used and efficient tool to help drive decision-making internationally. The Task Force would like to stress the importance of co-development of solutions with relevant stakeholders, and maintenance of health information in apps to ensure these remain evidence-based and consistent with best practice. Several general and domain-specific criteria are advised to assist HCPs in their assessment of clinical evidence to provide informed advice to patients about mHealth utilization
Capturing Ecosystem Services, Stakeholders' Preferences and Trade-Offs in Coastal Aquaculture Decisions : A Bayesian Belief Network Application
Aquaculture activities are embedded in complex social-ecological systems. However, aquaculture development decisions have tended to be driven by revenue generation, failing to account for interactions with the environment and the full value of the benefits derived from services provided by local ecosystems. Trade-offs resulting from changes in ecosystem services provision and associated impacts on livelihoods are also often overlooked. This paper proposes an innovative application of Bayesian belief networks - influence diagrams - as a decision support system for mediating trade-offs arising from the development of shrimp aquaculture in Thailand. Senior experts were consulted (n = 12) and primary farm data on the economics of shrimp farming (n = 20) were collected alongside secondary information on ecosystem services, in order to construct and populate the network. Trade-offs were quantitatively assessed through the generation of a probabilistic impact matrix. This matrix captures nonlinearity and uncertainty and describes the relative performance and impacts of shrimp farming management scenarios on local livelihoods. It also incorporates export revenues and provision and value of ecosystem services such as coastal protection and biodiversity. This research shows that Bayesian belief modeling can support complex decision-making on pathways for sustainable coastal aquaculture development and thus contributes to the debate on the role of aquaculture in social-ecological resilience and economic development
- …