The Hubble Space Telescope Extragalactic Distance Scale Key Project. X. The Cepheid Distance to NGC 7331

The distance to NGC 7331 has been derived from Cepheid variables observed with HST/WFPC2, as part of the Extragalactic Distance Scale Key Project. Multi-epoch exposures in F555W (V) and F814W (I), with photometry derived independently from DoPHOT and DAOPHOT/ALLFRAME programs, were used to detect a total of 13 reliable Cepheids, with periods between 11 and 42 days. The relative distance moduli between NGC 7331 and the LMC, imply an extinction to NGC 7331 of A_V = 0.47+-0.15 mag, and an extinction-corrected distance modulus to NGC 7331 of 30.89+-0.14(random) mag, equivalent to a distance of 15.1 Mpc. There are additional systematic uncertainties in the distance modulus of +-0.12 mag due to the calibration of the Cepheid Period-Luminosity relation, and a systematic offset of +0.05+-0.04 mag if we applied the metallicity correction inferred from the M101 results of Kennicutt et al 1998.Comment: To be published in The Astrophysical Journal, 1998 July 1, v501 note: Figs 1 and 2 (JPEG files) and Fig 7 (multipage .eps file) need to be viewed/printed separatel

Study of the HII regions in the spiral galaxy NGC6384

The galaxy NGC6384 has been observed with an IPCS through H alpha and [NII] narrow-band interference filters for direct imagery with the 2.6 m Byurakan telescope. We studied main physical parameters of identified 98 HII regions, their diameter and luminosity functions, as well [NII]/H alpha ratio distribution. The integrated distribution function of the HII region diameters can be well fitted by the exponential function. The characteristic diameter has the value (Do = 217 pc) predicted for a galaxy of its measured absolute luminosity. The luminosity function of HII regions has double power laws profile with relatively shallow slope at low luminosities (a = - 0.4), an abrupt turnover at log L(H alpha) = 38.75, and sharper slope at higher luminosities (a = - 2.3). Correlation between luminosity and diameter of HII regions confirms that in general they are constant density, radiation-bound systems. [NII]/H alpha ratio data for HII regions show that there is a negative radial gradient of [NII]/H alpha. In the central region of the galaxy, nitrogen abundance is higher than in the periphery. The properties of the HII regions population of this AGN galaxy does not differs significantly from the properties of the HII regions population of the "normal" galaxies. Reexamining the location of the type Ia SN 1971L in the galaxy, we confirm that it lies on the spiral arm at about 8.6" far from the closest HII region #53 (F81). Such a location can be taken as prove that the progenitor of this SN do not belong to an old, evolved stellar population.Comment: 17 pages, 7 figure

The Potential Energy Surface in Molecular Quantum Mechanics

The idea of a Potential Energy Surface (PES) forms the basis of almost all accounts of the mechanisms of chemical reactions, and much of theoretical molecular spectroscopy. It is assumed that, in principle, the PES can be calculated by means of clamped-nuclei electronic structure calculations based upon the Schr\"{o}dinger Coulomb Hamiltonian. This article is devoted to a discussion of the origin of the idea, its development in the context of the Old Quantum Theory, and its present status in the quantum mechanics of molecules. It is argued that its present status must be regarded as uncertain.Comment: 18 pages, Proceedings of QSCP-XVII, Turku, Finland 201

Trends and correlates of HIV-1 resistance among subjects failing an antiretroviral treatment over the 2003-2012 decade in Italy

BACKGROUND: Despite a substantial reduction in virological failures following introduction of new potent antiretroviral therapies in the latest years, drug resistance remains a limitation for the control of HIV-1 infection. We evaluated trends and correlates of resistance in treatment failing patients in a comprehensive database over a time period of relevant changes in prescription attitudes and treatment guidelines. METHODS: We analyzed 6,796 HIV-1 pol sequences from 49 centres stored in the Italian ARCA database during the 2003-2012 period. Patients (n = 5,246) with viremia > 200 copies/mL received a genotypic test while on treatment. Mutations were identified from IAS-USA 2013 tables. Class resistance was evaluated according to antiretroviral regimens in use at failure. Time trends and correlates of resistance were analyzed by Cochran-Armitage test and logistic regression models. RESULTS: The use of NRTI backbone regimens slightly decreased from 99.7% in 2003-2004 to 97.4% in 2010-2012. NNRTI-based combinations dropped from 46.7% to 24.1%. PI-containing regimens rose from 56.6% to 81.7%, with an increase of boosted PI from 36.5% to 68.9% overtime. In the same reference periods, Resistance to NRTIs, NNRTIs and PIs declined from 79.1% to 40.8%, from 77.8% to 53.8% and from 59.8% to 18.9%, respectively (p < .0001 for all comparisons). Dual NRTI + NNRTI and NRTI + PI resistance decreased from 56.4% to 33.3% and from 36.1% to 10.5%, respectively. Reduced risk of resistance over time periods was confirmed by a multivariate analysis. CONCLUSIONS: Mutations associated with NRTIs, NNRTIs and PIs at treatment failure declined overtime regardless of specific class combinations and epidemiological characteristics of treated population. This is likely due to the improvement of HIV treatment, including both last generation drug combinations and prescription guidelines

Dynamic temporary blood facility location-allocation during and post-disaster periods

The key objective of this study is to develop a tool (hybridization or integration of different techniques) for locating the temporary blood banks during and post-disaster conditions that could serve the hospitals with minimum response time. We have used temporary blood centers, which must be located in such a way that it is able to serve the demand of hospitals in nearby region within a shorter duration. We are locating the temporary blood centres for which we are minimizing the maximum distance with hospitals. We have used Tabu search heuristic method to calculate the optimal number of temporary blood centres considering cost components. In addition, we employ Bayesian belief network to prioritize the factors for locating the temporary blood facilities. Workability of our model and methodology is illustrated using a case study including blood centres and hospitals surrounding Jamshedpur city. Our results shows that at-least 6 temporary blood facilities are required to satisfy the demand of blood during and post-disaster periods in Jamshedpur. The results also show that that past disaster conditions, response time and convenience for access are the most important factors for locating the temporary blood facilities during and post-disaster periods

Structure and Function of the Human Respiratory Syncytial Virus M2–1 Protein

Human respiratory syncytial virus (HRSV) is a non-segmented negative stranded RNA virus and is recognized as the most important viral agent of lower respiratory tract infection worldwide, responsible for up to 199,000 deaths each year. The only FDA-approved regime to prevent HRSV-mediated disease is pre-exposure administration of a humanized HRSV-specific monoclonal antibody, which although being effective, is not in widespread usage due to its cost. No HRSV vaccine exists and so there remains a strong need for alternative and complementary anti-HRSV therapies. The HRSV M2–1 protein is a transcription factor and represents an attractive target for the development of antiviral compounds, based on its essential role in the viral replication cycle. To this end, a detailed analysis of M2–1 structure and functions will aid in identifying rational targets for structure-based antiviral drug design that can be developed in future translational research. Here we present an overview of the current understanding of the structure and function of HRSV M2–1, drawing on additional information derived from its structural homologues from other related viruses

Multi-messenger observations of a binary neutron star merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

Multimessenger NuEM Alerts with AMON

The Astrophysical Multimessenger Observatory Network (AMON), has developed a real-time multi-messenger alert system. The system performs coincidence analyses of datasets from gamma-ray and neutrino detectors, making the Neutrino-Electromagnetic (NuEM) alert channel. For these analyses, AMON takes advantage of sub-threshold events, i.e., events that by themselves are not significant in the individual detectors. The main purpose of this channel is to search for gamma-ray counterparts of neutrino events. We will describe the different analyses that make-up this channel and present a selection of recent results

Search for Spatial Correlations of Neutrinos with Ultra-high-energy Cosmic Rays

For several decades, the origin of ultra-high-energy cosmic rays (UHECRs) has been an unsolved question of high-energy astrophysics. One approach for solving this puzzle is to correlate UHECRs with high-energy neutrinos, since neutrinos are a direct probe of hadronic interactions of cosmic rays and are not deflected by magnetic fields. In this paper, we present three different approaches for correlating the arrival directions of neutrinos with the arrival directions of UHECRs. The neutrino data are provided by the IceCube Neutrino Observatory and ANTARES, while the UHECR data with energies above ∼50 EeV are provided by the Pierre Auger Observatory and the Telescope Array. All experiments provide increased statistics and improved reconstructions with respect to our previous results reported in 2015. The first analysis uses a high-statistics neutrino sample optimized for point-source searches to search for excesses of neutrino clustering in the vicinity of UHECR directions. The second analysis searches for an excess of UHECRs in the direction of the highest-energy neutrinos. The third analysis searches for an excess of pairs of UHECRs and highest-energy neutrinos on different angular scales. None of the analyses have found a significant excess, and previously reported overfluctuations are reduced in significance. Based on these results, we further constrain the neutrino flux spatially correlated with UHECRs

Long-term monitoring of the ANTARES optical module efficiencies using K-40 decays in sea water

[EN] Cherenkov light induced by radioactive decay products is one of the major sources of background light for deep-sea neutrino telescopes such as ANTARES. These decays are at the same time a powerful calibration source. Using data collected by the ANTARES neutrino telescope from mid 2008 to 2017, the time evolution of the photon detection ef¿ciency of optical modules is studied. A modest loss of only 20% in 9 years is observed. The relative time calibration between adjacent modules is derived as well.Albert, A.; Andre, M.; Anghinolfi, M.; Anton, G.; Ardid Ramírez, M.; Aubert, J.; Aublin, J.... (2018). Long-term monitoring of the ANTARES optical module efficiencies using K-40 decays in sea water. The European Physical Journal C. 78(8):1-8. https://doi.org/10.1140/epjc/s10052-018-6132-2S18788M. Ageron et al., ANTARES: The first undersea neutrino telescope. Nuclear Instruments and Methods in Physics Research A 656, 11–38 (2011)A. Albert et al., First all-flavor neutrino pointlike source search with the ANTARES neutrino telescope. Physical Review D 96, 082001 (2017)A. Albert et al., All-flavor Search for a Diffuse Flux of Cosmic Neutrinos with Nine Years of ANTARES Data. The Astrophysical Journal Letters 853, L7 (2018)B.P. Abbott et al., Multi-messenger Observations of a Binary Neutron Star Merger. The Astrophysical Journal Letters 848, L12 (2017)S. Adrián-Martínez et al., Measurement of atmospheric neutrino oscillations with the ANTARES neutrino telescope. Physics Letters B 714, 224–230 (2012)A. Albert et al., Search for relativistic magnetic monopoles with five years of the ANTARES detector data. Journal of High Energy Physics 7, 54 (2017)S. Adrián-Martínez et al., Limits on dark matter annihilation in the sun using the ANTARES neutrino telescope. Physics Letters B 759, 69–74 (2016)A. Albert et al., Results from the search for dark matter in the Milky Way with 9 years of data of the ANTARES neutrino telescope. Physics Letters B 769, 249–254 (2017)M.G. Aartsen et al., The IceCube Neutrino Observatory: instrumentation and online systems. Journal of Instrumentation 12, P03012 (2017)K. Abe et al., Calibration of the Super-Kamiokande detector. Nuclear Instruments and Methods in Physics Research A 737, 253–272 (2014)P. Amram et al., The ANTARES optical module. Nuclear Instruments and Methods in Physics Research A 484, 369–383 (2002)S. Adrián-Martínez et al., The positioning system of the ANTARES Neutrino Telescope. Journal of Instrumentation 7, T08002 (2012)J.A. Aguilar et al., Performance of the front-end electronics of the ANTARES neutrino telescope. Nuclear Instruments and Methods in Physics Research A 622, 59–73 (2010)J.A. Aguilar et al., The data acquisition system for the ANTARES neutrino telescope. Nuclear Instruments and Methods in Physics Research A 570, 107–116 (2007)J.A. Aguilar et al., Measurement of the atmospheric muon flux with a 4 GeV threshold in the ANTARES neutrino telescope. Astroparticle Physics 33, 86–90 (2010)J.A. Aguilar et al., Transmission of light in deep sea water at the site of the ANTARES neutrino telescope. Astroparticle Physics 23, 131–155 (2005)S. Kim et al., PubChem Substance and Compound databases. Nucleic Acids Research 44, 1202–13 (2016)G. Audi et al., The NUBASE evaluation of nuclear and decay properties. Nuclear Physics A 729, 3–128 (2003)J. Floor Anthoni. The chemical composition of seawater. http://www.seafriends.org.nz/oceano/seawater.htmJ.R. De Laeter et al., Atomic Weights of the Elements: Review 2000 (IUPAC Technical Report). Pure Applied Chemistry 75, 683–800 (2003)P. Amram et al., Background light in potential sites for the ANTARES undersea neutrino telescope. Astroparticle Physics 13, 127–136 (2000)C. Tamburini et al., Deep-sea bioluminescence blooms after dense water formation at the ocean surface. PLOS ONE, 8(7), (2013)J.A. Aguilar et al., Time calibration of the ANTARES neutrino telescope. Astroparticle Physics 34, 539–549 (2011)M. Ageron et al., The ANTARES optical beacon system. Nuclear Instruments and Methods in Physics Research A 578, 498–509 (2007)S. Adrián-Martínez et al., Time calibration with atmospheric muon tracks in the ANTARES neutrino telescope. Astroparticle Physics 78, 43–51 (2016)S. Adrián-Martínez et al., Letter of Intent for KM3NeT 2.0. Journal of Physics G. Nuclear Physics 43(8), 084001 (2016