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

Five years of searches for point sources of astrophysical neutrinos with the AMANDA-II neutrino telescope

We report the results of a five-year survey of the northern sky to search for point sources of high energy neutrinos. The search was performed on the data collected with the AMANDA-II neutrino telescope in the years 2000 to 2004, with a live time of 1001 days. The sample of selected events consists of 4282 upward going muon tracks with high reconstruction quality and an energy larger than about 100 GeV. We found no indication of point sources of neutrinos and set 90% confidence level flux upper limits for an all-sky search and also for a catalog of 32 selected sources. For the all-sky search, our average (over declination and right ascension) experimentally observed upper limit Phi(0)=(E/1 TeV)(gamma)center dot d Phi/dE to a point source flux of muon and tau neutrino (detected as muons arising from taus) is Phi(nu mu)+nu(0)(mu)+Phi(nu tau)+nu(0)(tau)=11.1x 10(-11) TeV-1 cm(-2) s(-1), in the energy range between 1.6 TeV and 2.5 PeV for a flavor ratio Phi(nu mu)+nu(0)(mu)/Phi(nu tau)+nu(0)(tau)=1 and assuming a spectral index gamma=2. It should be noticed that this is the first time we set upper limits to the flux of muon and tau neutrinos. In previous papers we provided muon neutrino upper limits only neglecting the sensitivity to a signal from tau neutrinos, which improves the limits by 10% to 16%. The value of the average upper limit presented in this work corresponds to twice the limit on the muon neutrino flux Phi(nu mu)+nu(0)(mu)=5.5x10(-11) TeV-1 cm(-2) s(-1). A stacking analysis for preselected active galactic nuclei and a search based on the angular separation of the events were also performed. We report the most stringent flux upper limits to date, including the results of a detailed assessment of systematic uncertainties

Linking Hydrogen (δ2H) Isotopes in Feathers and Precipitation: Sources of Variance and Consequences for Assignment to Isoscapes

Background: Tracking small migrant organisms worldwide has been hampered by technological and recovery limitations and sampling bias inherent in exogenous markers. Naturally occurring stable isotopes of H (d 2 H) in feathers provide an alternative intrinsic marker of animal origin due to the predictable spatial linkage to underlying hydrologically driven flow of H isotopes into foodwebs. This approach can assess the likelihood that a migrant animal originated from a given location(s) within a continent but requires a robust algorithm linking H isotopes in tissues of interest to an appropriate hydrological isotopic spatio-temporal pattern, such as weighted-annual rainfall. However, a number of factors contribute to or alter expected isotopic patterns in animals. We present results of an extensive investigation into taxonomic and environmental factors influencing feather d 2 H patterns across North America. Principal Findings: Stable isotope data were measured from 544 feathers from 40 species and 140 known locations. For d 2 H, the most parsimonious model explaining 83 % of the isotopic variance was found with amount-weighted growingseason precipitation d 2 H, foraging substrate and migratory strategy. Conclusions/Significance: This extensive H isotopic analysis of known-origin feathers of songbirds in North America and elsewhere reconfirmed the strong coupling between tissue d 2 H and global hydrologic d 2 H patterns, and accounting for variance associated with foraging substrate and migratory strategy, can be used in conservation and research for th

Follicular fluid content and oocyte quality: from single biochemical markers to metabolomics

The assessment of oocyte quality in human in vitro fertilization (IVF) is getting increasing attention from embryologists. Oocyte selection and the identification of the best oocytes, in fact, would help to limit embryo overproduction and to improve the results of oocyte cryostorage programs. Follicular fluid (FF) is easily available during oocyte pick-up and theorically represents an optimal source on non-invasive biochemical predictors of oocyte quality. Unfortunately, however, the studies aiming to find a good molecular predictor of oocyte quality in FF were not able to identify substances that could be used as reliable markers of oocyte competence to fertilization, embryo development and pregnancy. In the last years, a well definite trend toward passing from the research of single molecular markers to more complex techniques that study all metabolites of FF has been observed. The metabolomic approach is a powerful tool to study biochemical predictors of oocyte quality in FF, but its application in this area is still at the beginning. This review provides an overview of the current knowledge about the biochemical predictors of oocyte quality in FF, describing both the results coming from studies on single biochemical markers and those deriving from the most recent studies of metabolomic

The bodily social self: a link between phenomenal and narrative selfhood

The Phenomenal Self (PS) is widely considered to be dependent on body representations, whereas the Narrative Self (NS) is generally thought to rely on abstract cognitive representations. The concept of the Bodily Social Self (BSS) might play an important role in explaining how the high level cognitive self-representations enabling the NS might emerge from the bodily basis of the PS. First, the phenomenal self (PS) and narrative self (NS), are briefly examined. Next, the BSS is defined and its potential for explaining aspects of social cognition is explored. The minimal requirements for a BSS are considered, before reviewing empirical evidence regarding the development of the BSS over the first year of life. Finally, evidence on the involvement of the body in social distinctions between self and other is reviewed to illustrate how the BSS is affected by both the bottom up effects of multisensory stimulation and the top down effects of social identification

Spontaneous Facial Expression Analysis Using Optical Flow Technique

© 2019, Springer Nature Switzerland AG. Investigation of emotions manifested through facial expressions has valuable applications in predictive behavioural studies. A potential application may be to impart intelligence to surveillance systems such as Closed-Circuit Television (CCTV) systems for recognition of emotional facial expressions. A facial recognition program tailored to evaluating facial behaviour for real time application can be met if patterns of emotions can be detected. An exploratory analysis of optical flow data was conducted with an aim to detect patterns and trends to differentiate between the emotional facial expressions: amusement, sadness and fear from the frontal and profile facial orientations. Analysis was in the form of emotion maps constructed from feature vectors obtained by using the Lucas-Kanade implementation of optical flow. Classification of individual emotions showed recognition of amusement was much greater in comparison to the recognition of the negative emotions, sadness and fear. Recognition was not negatively affected using reduced set of feature vectors derived from the emotion maps. Further investigation is necessary to assess the utility of emotion maps to visualise feature representations of emotional expression