Observation of Gravitational Waves from a Binary Black Hole Merger

On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory simultaneously observed a transient gravitational-wave signal. The signal sweeps upwards in frequency from 35 to 250 Hz with a peak gravitational-wave strain of 1.0×10(-21). It matches the waveform predicted by general relativity for the inspiral and merger of a pair of black holes and the ringdown of the resulting single black hole. The signal was observed with a matched-filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203,000 years, equivalent to a significance greater than 5.1σ. The source lies at a luminosity distance of 410(-180)(+160)  Mpc corresponding to a redshift z=0.09(-0.04)(+0.03). In the source frame, the initial black hole masses are 36(-4)(+5)M⊙ and 29(-4)(+4)M⊙, and the final black hole mass is 62(-4)(+4)M⊙, with 3.0(-0.5)(+0.5)M⊙c(2) radiated in gravitational waves. All uncertainties define 90% credible intervals. These observations demonstrate the existence of binary stellar-mass black hole systems. This is the first direct detection of gravitational waves and the first observation of a binary black hole merger.

GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral

On August 17, 2017 at 12∶41:04 UTC the Advanced LIGO and Advanced Virgo gravitational-wave detectors made their first observation of a binary neutron star inspiral. The signal, GW170817, was detected with a combined signal-to-noise ratio of 32.4 and a false-alarm-rate estimate of less than one per 8.0×10^{4}  years. We infer the component masses of the binary to be between 0.86 and 2.26  M_{⊙}, in agreement with masses of known neutron stars. Restricting the component spins to the range inferred in binary neutron stars, we find the component masses to be in the range 1.17-1.60  M_{⊙}, with the total mass of the system 2.74_{-0.01}^{+0.04}M_{⊙}. The source was localized within a sky region of 28  deg^{2} (90% probability) and had a luminosity distance of 40_{-14}^{+8}  Mpc, the closest and most precisely localized gravitational-wave signal yet. The association with the γ-ray burst GRB 170817A, detected by Fermi-GBM 1.7 s after the coalescence, corroborates the hypothesis of a neutron star merger and provides the first direct evidence of a link between these mergers and short γ-ray bursts. Subsequent identification of transient counterparts across the electromagnetic spectrum in the same location further supports the interpretation of this event as a neutron star merger. This unprecedented joint gravitational and electromagnetic observation provides insight into astrophysics, dense matter, gravitation, and cosmology.

GW151226: Observation of Gravitational Waves from a 22-Solar-Mass Binary Black Hole Coalescence

We report the observation of a gravitational-wave signal produced by the coalescence of two stellar-mass black holes. The signal, GW151226, was observed by the twin detectors of the Laser Interferometer Gravitational-Wave Observatory (LIGO) on December 26, 2015 at 03:38:53 UTC. The signal was initially identified within 70 s by an online matched-filter search targeting binary coalescences. Subsequent off-line analyses recovered GW151226 with a network signal-to-noise ratio of 13 and a significance greater than 5σ. The signal persisted in the LIGO frequency band for approximately 1 s, increasing in frequency and amplitude over about 55 cycles from 35 to 450 Hz, and reached a peak gravitational strain of 3.4_{-0.9}^{+0.7}×10^{-22}. The inferred source-frame initial black hole masses are 14.2_{-3.7}^{+8.3}M_{⊙} and 7.5_{-2.3}^{+2.3}M_{⊙}, and the final black hole mass is 20.8_{-1.7}^{+6.1}M_{⊙}. We find that at least one of the component black holes has spin greater than 0.2. This source is located at a luminosity distance of 440_{-190}^{+180}  Mpc corresponding to a redshift of 0.09_{-0.04}^{+0.03}. All uncertainties define a 90% credible interval. This second gravitational-wave observation provides improved constraints on stellar populations and on deviations from general relativity.

GW170104: Observation of a 50-Solar-Mass Binary Black Hole Coalescence at Redshift 0.2

We describe the observation of GW170104, a gravitational-wave signal produced by the coalescence of a pair of stellar-mass black holes. The signal was measured on January 4, 2017 at 10∶11:58.6 UTC by the twin advanced detectors of the Laser Interferometer Gravitational-Wave Observatory during their second observing run, with a network signal-to-noise ratio of 13 and a false alarm rate less than 1 in 70 000 years. The inferred component black hole masses are 31.2_{-6.0}^{+8.4}M_{⊙} and 19.4_{-5.9}^{+5.3}M_{⊙} (at the 90% credible level). The black hole spins are best constrained through measurement of the effective inspiral spin parameter, a mass-weighted combination of the spin components perpendicular to the orbital plane, χ_{eff}=-0.12_{-0.30}^{+0.21}. This result implies that spin configurations with both component spins positively aligned with the orbital angular momentum are disfavored. The source luminosity distance is 880_{-390}^{+450}  Mpc corresponding to a redshift of z=0.18_{-0.07}^{+0.08}. We constrain the magnitude of modifications to the gravitational-wave dispersion relation and perform null tests of general relativity. Assuming that gravitons are dispersed in vacuum like massive particles, we bound the graviton mass to m_{g}≤7.7×10^{-23}  eV/c^{2}. In all cases, we find that GW170104 is consistent with general relativity.

GW170814: A Three-Detector Observation of Gravitational Waves from a Binary Black Hole Coalescence

On August 14, 2017 at 10∶30:43 UTC, the Advanced Virgo detector and the two Advanced LIGO detectors coherently observed a transient gravitational-wave signal produced by the coalescence of two stellar mass black holes, with a false-alarm rate of ≲1 in 27 000 years. The signal was observed with a three-detector network matched-filter signal-to-noise ratio of 18. The inferred masses of the initial black holes are 30.5_{-3.0}^{+5.7}M_{⊙} and 25.3_{-4.2}^{+2.8}M_{⊙} (at the 90% credible level). The luminosity distance of the source is 540_{-210}^{+130}  Mpc, corresponding to a redshift of z=0.11_{-0.04}^{+0.03}. A network of three detectors improves the sky localization of the source, reducing the area of the 90% credible region from 1160   deg^{2} using only the two LIGO detectors to 60  deg^{2} using all three detectors. For the first time, we can test the nature of gravitational-wave polarizations from the antenna response of the LIGO-Virgo network, thus enabling a new class of phenomenological tests of gravity.

Hepatitis C virus and porphyria cutanea tarda: evidence of a strong association

Porphyria cutanea tarda in human beings is believed to be due to reduced hepatic uroporphyrinogen decarboxylase activity. However, extrinsic factors such as alcohol abuse and drug intake are required for clinical manifestation of the disease. In addition to typical cutaneous lesions, patients with porphyria cutanea tarda usually have chronic liver disease and moderate iron overload. Of 74 Italian patients with porphyria cutanea tarda, hepatitis C virus antibodies were detected in 76% by enzyme-linked immunoassay and in 82% by recombinant immunoblot assay. Viral genome, studied with nested polymerase chain reaction, was found in the sera of 49 subjects--47 positive and 2 indeterminate on recombinant immunoblot assay. Five percent of the patients were HBsAg-positive, and about 40% had had past hepatitis B contacts. Alcohol abuse was present in 38%. Liver biopsies performed in 42 patients showed chronic persistent hepatitis in 7 patients, chronic active hepatitis in 22 patients, fibrosis in three patients and cirrhosis in 10 patients. Hepatitis C virus antibody was detected in 100% of patients with chronic active hepatitis and in about 80% of all other groups. Alcohol abuse was more frequent in patients with cirrhosis (80%) than in the other groups. In Italian patients with porphyria cutanea tarda, the prevalence of hepatitis C virus infection was very high, comparable to that in non-A, non-B hepatitis and high-risk patient groups. Hepatitis C virus is probably the main pathogenetic factor of the liver disease of patients with porphyria cutanea tarda.

GW170817: Measurements of Neutron Star Radii and Equation of State

On 17 August 2017, the LIGO and Virgo observatories made the first direct detection of gravitational waves from the coalescence of a neutron star binary system. The detection of this gravitational-wave signal, GW170817, offers a novel opportunity to directly probe the properties of matter at the extreme conditions found in the interior of these stars. The initial, minimal-assumption analysis of the LIGO and Virgo data placed constraints on the tidal effects of the coalescing bodies, which were then translated to constraints on neutron star radii. Here, we expand upon previous analyses by working under the hypothesis that both bodies were neutron stars that are described by the same equation of state and have spins within the range observed in Galactic binary neutron stars. Our analysis employs two methods: the use of equation-of-state-insensitive relations between various macroscopic properties of the neutron stars and the use of an efficient parametrization of the defining function p(ρ) of the equation of state itself. From the LIGO and Virgo data alone and the first method, we measure the two neutron star radii as R_{1}=10.8_{-1.7}^{+2.0}  km for the heavier star and R_{2}=10.7_{-1.5}^{+2.1}  km for the lighter star at the 90% credible level. If we additionally require that the equation of state supports neutron stars with masses larger than 1.97  M_{⊙} as required from electromagnetic observations and employ the equation-of-state parametrization, we further constrain R_{1}=11.9_{-1.4}^{+1.4}  km and R_{2}=11.9_{-1.4}^{+1.4}  km at the 90% credible level. Finally, we obtain constraints on p(ρ) at supranuclear densities, with pressure at twice nuclear saturation density measured at 3.5_{-1.7}^{+2.7}×10^{34}  dyn cm^{-2} at the 90% level.

Tests of General Relativity with GW150914

The LIGO detection of GW150914 provides an unprecedented opportunity to study the two-body motion of a compact-object binary in the large-velocity, highly nonlinear regime, and to witness the final merger of the binary and the excitation of uniquely relativistic modes of the gravitational field. We carry out several investigations to determine whether GW150914 is consistent with a binary black-hole merger in general relativity. We find that the final remnant's mass and spin, as determined from the low-frequency (inspiral) and high-frequency (postinspiral) phases of the signal, are mutually consistent with the binary black-hole solution in general relativity. Furthermore, the data following the peak of GW150914 are consistent with the least-damped quasinormal mode inferred from the mass and spin of the remnant black hole. By using waveform models that allow for parametrized general-relativity violations during the inspiral and merger phases, we perform quantitative tests on the gravitational-wave phase in the dynamical regime and we determine the first empirical bounds on several high-order post-Newtonian coefficients. We constrain the graviton Compton wavelength, assuming that gravitons are dispersed in vacuum in the same way as particles with mass, obtaining a 90%-confidence lower bound of 10^{13}  km. In conclusion, within our statistical uncertainties, we find no evidence for violations of general relativity in the genuinely strong-field regime of gravity.

Palmitoylethanolamide reduces pain-related behaviors and restores glutamatergic synapses homeostasis in the medial prefrontal cortex of neuropathic mice

BACKGROUND

Enhanced supraspinal glutamate levels following nerve injury are associated with pathophysiological mechanisms responsible for neuropathic pain. Chronic pain can interfere with specific brain areas involved in glutamate-dependent neuropsychological processes, such as cognition, memory, and decision-making. The medial prefrontal cortex (mPFC) is thought to play a critical role in pain-related depression and anxiety, which are frequent co-morbidities of chronic pain. Using an animal model of spared nerve injury (SNI) of the sciatic nerve, we assess bio-molecular modifications in glutamatergic synapses in the mPFC that underlie neuropathic pain-induced plastic changes at 30 days post-surgery. Moreover, we examine the effects of palmitoylethanolamide (PEA) administration on pain-related behaviours, as well as the cortical biochemical and morphological changes that occur in SNI animals.

RESULTS

At 1 month, SNI was associated with mechanical and thermal hypersensitivity, as well as depression-like behaviour, cognitive impairments, and obsessive-compulsive activities. Moreover, we observed an overall glutamate synapse modification in the mPFC, characterized by changes in synaptic density proteins and amino acid levels. Finally, with regard to the resolution of pain and depressive-like syndrome in SNI mice, PEA restored the glutamatergic synapse proteins and changes in amino acid release.

CONCLUSIONS

Given the potential role of the mPFC in pain mechanisms, our findings may provide novel insights into neuropathic pain forebrain processes and indicate PEA as a new pharmacological tool to treat neuropathic pain and the related negative affective states. Graphical Abstract Palmitoylethanolamide: a new pharmacological tool to treat neuropathic pain and the related negative affective states.

Palmitoylethanolamide induces microglia changes associated with increased migration and phagocytic activity: involvement of the CB2 receptor

The endogenous fatty acid amide palmitoylethanolamide (PEA) has been shown to exert anti-inflammatory actions mainly through inhibition of the release of pro-inflammatory molecules from mast cells, monocytes and macrophages. Indirect activation of the endocannabinoid (eCB) system is among the several mechanisms of action that have been proposed to underlie the different effects of PEA in vivo. In this study, we used cultured rat microglia and human macrophages to evaluate whether PEA affects eCB signaling. PEA was found to increase CB2 mRNA and protein expression through peroxisome proliferator-activated receptor-α (PPAR-α) activation. This novel gene regulation mechanism was demonstrated through: (i) pharmacological PPAR-α manipulation, (ii) PPAR-α mRNA silencing, (iii) chromatin immunoprecipitation. Moreover, exposure to PEA induced morphological changes associated with a reactive microglial phenotype, including increased phagocytosis and migratory activity. Our findings suggest indirect regulation of microglial CB2R expression as a new possible mechanism underlying the effects of PEA. PEA can be explored as a useful tool for preventing/treating the symptoms associated with neuroinflammation in CNS disorders.

The effects of iodoprophylaxis on thyroid size during pregnancy

Thyroid gland size was ultrasonographically determined in 35 pregnant women who live in an area with moderate iodine deficiency. Iodide salt was administered to group A (n = 17), whereas group B (n = 18) was used as a control. Each group was tested for thyroid-stimulating hormone serum levels, iodine excretion, and thyroid volume. In both groups thyroid-stimulating hormone levels were similar and did not change throughout pregnancy. The iodine excretion at the third trimester in the treated group was significantly (p less than 0.01) higher than that of group B (100.0 +/- 39.0 versus 50.0 +/- 37.0 micrograms iodine per 24 hours, respectively). Initially, thyroid volume did not differ between the two groups. At the end of pregnancy, no difference was found in thyroid size in group A, whereas in the untreated women it increased significantly (p less than 0.0001) with a mean increase of 1.6 +/- 0.6 ml (16.2% +/- 6.0%). These results show that the increased thyroid size in the control group was mainly a result of relative iodine deficiency and that iodoprophylaxis should be warranted even in areas with moderate iodine deficiency to prevent the increase in thyroid size and, probably, to avoid the risk of maternal and fetal hypothyroidism.

New evidence for a membrane-bound pathway in hormone receptor binding

The fully active cholecystokinin analog (Thr,Nle)-CCK-9 was lipo-derivatized by N-terminal grafting of a dimyristoylglycerol moiety to induce tight interdigitation with cell membrane bilayers. While the parent CCK peptide was shown to interact only transiently with small unilamellar phospholipid vesicles, the lipo-CCK peptide, although self-aggregating into vesicles, inserts rapidly and quantitatively into phospholipid bilayers. Fluorescence and, even more so, NMR data are supportive for a chain reversal of the CCK moiety of the lipo derivative with embedment of the C-terminus into hydrophobic compartments of the bilayer. MD simulations allowed for a proposal of the folded form of CCK in bilayers with a helical array parallel to the interface and an amphipathic display of the side chains. In this model, the phenylalanine aromatic ring is heading the peptide molecule and may thus play a decisive role in the lateral penetration of the receptor at the water/lipid interface. In fact, despite the membrane-bound state, its binding affinity for rat pancreatic acini is comparable to that of the CCK peptide when tested after a 3-h equilibration period but 5-6-fold lower at 45 min, suggesting that the association rate is significantly lower than that of the unmodified CCK peptide. This can rationally be attributed to the tight interdigitation of the double-tailed lipo moiety with the membrane bilayer. Moreover, an escape of the lipopeptide into the extracellular aqueous phase is energetically highly unfavored; therefore, the receptor can only be reached by a membrane-bound two-dimensional migration. The observed difference in amplification between binding and amylase secretion may result from inadequate occupation of low-affinity CCK receptors, which leads then to poor couplings to G-proteins. Nevertheless the data confirm that lateral penetration of receptor structures is possible, and thus, preadsorption of peptide (neuro)hormones at the cell membrane bilayer may indeed represent the first step in the receptor recognition process.

Properties of the Binary Black Hole Merger GW150914

On September 14, 2015, the Laser Interferometer Gravitational-Wave Observatory (LIGO) detected a gravitational-wave transient (GW150914); we characterize the properties of the source and its parameters. The data around the time of the event were analyzed coherently across the LIGO network using a suite of accurate waveform models that describe gravitational waves from a compact binary system in general relativity. GW150914 was produced by a nearly equal mass binary black hole of masses 36_{-4}^{+5}M_{⊙} and 29_{-4}^{+4}M_{⊙}; for each parameter we report the median value and the range of the 90% credible interval. The dimensionless spin magnitude of the more massive black hole is bound to be <0.7 (at 90% probability). The luminosity distance to the source is 410_{-180}^{+160}  Mpc, corresponding to a redshift 0.09_{-0.04}^{+0.03} assuming standard cosmology. The source location is constrained to an annulus section of 610  deg^{2}, primarily in the southern hemisphere. The binary merges into a black hole of mass 62_{-4}^{+4}M_{⊙} and spin 0.67_{-0.07}^{+0.05}. This black hole is significantly more massive than any other inferred from electromagnetic observations in the stellar-mass regime.

Increasing the Astrophysical Reach of the Advanced Virgo Detector via the Application of Squeezed Vacuum States of Light

Current interferometric gravitational-wave detectors are limited by quantum noise over a wide range of their measurement bandwidth. One method to overcome the quantum limit is the injection of squeezed vacuum states of light into the interferometer's dark port. Here, we report on the successful application of this quantum technology to improve the shot noise limited sensitivity of the Advanced Virgo gravitational-wave detector. A sensitivity enhancement of up to 3.2±0.1  dB beyond the shot noise limit is achieved. This nonclassical improvement corresponds to a 5%-8% increase of the binary neutron star horizon. The squeezing injection was fully automated and over the first 5 months of the third joint LIGO-Virgo observation run O3 squeezing was applied for more than 99% of the science time. During this period several gravitational-wave candidates have been recorded.

Symptomatology and comorbidity of generalized anxiety disorder in children and adolescents

This study investigated the symptomatology and comorbidity of generalized anxiety disorder (GAD) in a clinically referred sample of Italian children and adolescents as a function of age and gender. The sample consisted of 58 subjects (19 children and 39 adolescents), 23 males and 35 females screened from consecutively referred children and adolescents. This sample was divided into two groups of younger children (19 subjects, eight males and 11 females aged 7 to 12 years; mean age, 9.6) and adolescents (39 subjects, 15 males and 24 females aged 12 to 18 years; mean age, 14.9). Feelings of tension, apprehension, the need for reassurance, irritability, negative self-image, and physical complaints were reported in more than 70% of the subjects. Differences in the symptomatic profile between males and females were not significant. Children and adolescents did not show significant differences in the number of symptoms. The need for reassurance was significantly more frequent in children, and brooding was more frequent in adolescents. Other anxiety disorders were commonly comorbid with GAD. More than half of the patients with GAD showed a concurrent depressive disorder; no differences were found for comorbidity between children and adolescents, except for higher rates of separation anxiety disorder in children.

Lapatinib in breast cancer

Aberrant activation of some members of human epidermal growth factor receptor (HER) family plays a key role in breast carcinogenesis. Lapatinib is an oral dual tyrosine kinase inhibitor selective for inhibition of epidermal growth factor receptor (EGFR/ErbB1) and HER2/ErbB2. Having more targets, probably its antitumor activity could be more efficient. Clinical data have shown that lapatinib is active in HER2-positive breast cancer as monotherapy, in combination with trastuzumab, and in trastuzumab-resistant patients. Phase I clinical trials have shown also that lapatinib is well tolerated, with mild diarrhea and skin rush as common toxic effects and low incidence of cardiotoxicity. Phase II and III clinical trials' data provide encouraging evidence of the clinical effectiveness of lapatinib in advanced or metastatic breast cancer and for its potential in patients with brain metastases. Interim results from the large, phase III trial in 392 patients showed that in combination with capecitabine lapatinib almost doubled time to progression when compared with capecitabine alone. Several clinical trials that explore the efficacy of lapatinib in combination with conventional chemotherapeutic agents [paclitaxel (Taxol), capecitabine and platinoids], hormonotherapy and other target therapies are ongoing in advanced breast cancer or in neo-adjuvant and adjuvant settings. Our improved understanding of the biology of breast cancer and the use of biomarkers for identification of specific subtypes are allowing us to bring patient-specific novel therapies such as lapatinib to the clinic.

GW190521: A Binary Black Hole Merger with a Total Mass of 150 M_{⊙}

On May 21, 2019 at 03:02:29 UTC Advanced LIGO and Advanced Virgo observed a short duration gravitational-wave signal, GW190521, with a three-detector network signal-to-noise ratio of 14.7, and an estimated false-alarm rate of 1 in 4900 yr using a search sensitive to generic transients. If GW190521 is from a quasicircular binary inspiral, then the detected signal is consistent with the merger of two black holes with masses of 85_{-14}^{+21}  M_{⊙} and 66_{-18}^{+17}  M_{⊙} (90% credible intervals). We infer that the primary black hole mass lies within the gap produced by (pulsational) pair-instability supernova processes, with only a 0.32% probability of being below 65  M_{⊙}. We calculate the mass of the remnant to be 142_{-16}^{+28}  M_{⊙}, which can be considered an intermediate mass black hole (IMBH). The luminosity distance of the source is 5.3_{-2.6}^{+2.4}  Gpc, corresponding to a redshift of 0.82_{-0.34}^{+0.28}. The inferred rate of mergers similar to GW190521 is 0.13_{-0.11}^{+0.30}  Gpc^{-3} yr^{-1}.

Prospects for observing and localizing gravitational-wave transients with Advanced LIGO, Advanced Virgo and KAGRA

We present possible observing scenarios for the Advanced LIGO, Advanced Virgo and KAGRA gravitational-wave detectors over the next decade, with the intention of providing information to the astronomy community to facilitate planning for multi-messenger astronomy with gravitational waves. We estimate the sensitivity of the network to transient gravitational-wave signals, and study the capability of the network to determine the sky location of the source. We report our findings for gravitational-wave transients, with particular focus on gravitational-wave signals from the inspiral of binary neutron star systems, which are the most promising targets for multi-messenger astronomy. The ability to localize the sources of the detected signals depends on the geographical distribution of the detectors and their relative sensitivity, and [Formula: see text] credible regions can be as large as thousands of square degrees when only two sensitive detectors are operational. Determining the sky position of a significant fraction of detected signals to areas of 5-[Formula: see text] requires at least three detectors of sensitivity within a factor of [Formula: see text] of each other and with a broad frequency bandwidth. When all detectors, including KAGRA and the third LIGO detector in India, reach design sensitivity, a significant fraction of gravitational-wave signals will be localized to a few square degrees by gravitational-wave observations alone.

Changes in the proportion of types I and III collagen in the left ventricular wall of patients with post-irradiative pericarditis

Pericardiectomy for post-irradiative constrictive pericarditis achieves poor results because of the extensive damage to the heart and pericardium caused by ionizing radiation. The extracellular structural protein, collagen, is responsible for the functional integrity of the myocardium and allows reversible interdigitation and the transmission of force between contracting myocytes. Collagen concentration and composition were examined in the cardiac tissue of three patients undergoing pericardiectomy and post-irradiative pericarditis. Normal heart tissue was taken at autopsy from patients without cardiac disease and acted as controls. Total collagen concentration (mean(s.e.m.)) was significantly increased in the ventricular tissue of patients with post-irradiative pericarditis compared with that of the controls (119.8(16.6) versus 50.4(5.2) mg/g dry weight, P<0.01). Although there was an increase in concentration of both type I and III collagen, a disproportional increase in type I was observed. The proportion of type III collagen was lower in patients with post-irradiative pericarditis than in the control group (33(2.6)% versus 38.2(3.7)%, P<0.05). The results of the present study suggest that this marked alteration in collagen concentration and proportion may contribute to the impaired diastolic distensibility of the ventricles seen in this group of patients.

Prospects for Observing and Localizing Gravitational-Wave Transients with Advanced LIGO and Advanced Virgo

We present a possible observing scenario for the Advanced LIGO and Advanced Virgo gravitational-wave detectors over the next decade, with the intention of providing information to the astronomy community to facilitate planning for multi-messenger astronomy with gravitational waves. We determine the expected sensitivity of the network to transient gravitational-wave signals, and study the capability of the network to determine the sky location of the source. We report our findings for gravitational-wave transients, with particular focus on gravitational-wave signals from the inspiral of binary neutron-star systems, which are considered the most promising for multi-messenger astronomy. The ability to localize the sources of the detected signals depends on the geographical distribution of the detectors and their relative sensitivity, and 90% credible regions can be as large as thousands of square degrees when only two sensitive detectors are operational. Determining the sky position of a significant fraction of detected signals to areas of 5 deg2 to 20 deg2 will require at least three detectors of sensitivity within a factor of ∼ 2 of each other and with a broad frequency bandwidth. Should the third LIGO detector be relocated to India as expected, a significant fraction of gravitational-wave signals will be localized to a few square degrees by gravitational-wave observations alone.

GW150914: First results from the search for binary black hole coalescence with Advanced LIGO

On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-wave Observatory (LIGO) simultaneously observed the binary black hole merger GW150914. We report the results of a matched-filter search using relativistic models of compact-object binaries that recovered GW150914 as the most significant event during the coincident observations between the two LIGO detectors from September 12 to October 20, 2015. GW150914 was observed with a matched filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203000 years, equivalent to a significance greater than 5.1 σ.

Immunohistochemical evidence for a lack of ferritin in duodenal absorptive epithelial cells in idiopathic hemochromatosis

Patients with idiopathic hemochromatosis exhibit an unexplained increase in intestinal iron absorption. The aim of this work was to study immunohistochemical H- and L-ferritin distribution in duodenal mucosal cells of patients with idiopathic hemochromatosis, and of subjects with various degrees of iron loading. Biopsy sections of gastrointestinal mucosa from 24 patients with idiopathic hemochromatosis, 10 patients with secondary iron overload, 6 normal subjects, and 13 iron-deficient subjects were analyzed with monoclonal antibodies for the presence of immunohistochemical H and L ferritin types, and with Perls' stain for hemosiderin. Ferritin content of duodenal homogenates was evaluated in 5 cases. The absorptive duodenal cells were found to contain ferritin, mostly of the L type, in apical granules; these ferritin granules were present in all normal, iron-deficient, and iron-over-loaded subjects, but were absent in 21 (87%) of the patients with established idiopathic hemochromatosis. In cells other than those of the duodenal epithelium, such as lamina propria or antral mucosa, ferritin and hemosiderin contents were related to iron loading and no difference was evident between primary and secondary iron overload. These findings indicate that (a) idiopathic hemochromatosis is associated with an altered ferritin expression in the duodenal absorptive epithelial cells, (b) this alteration cannot be detected by analysis of duodenal homogenates, (c) idiopathic hemochromatosis does not affect ferritin accumulation in the other cell types analyzed, and (d) ferritin in absorptive duodenal cells may have a regulatory role in iron absorption.

Prospects for observing and localizing gravitational-wave transients with Advanced LIGO, Advanced Virgo and KAGRA

We present our current best estimate of the plausible observing scenarios for the Advanced LIGO, Advanced Virgo and KAGRA gravitational-wave detectors over the next several years, with the intention of providing information to facilitate planning for multi-messenger astronomy with gravitational waves. We estimate the sensitivity of the network to transient gravitational-wave signals for the third (O3), fourth (O4) and fifth observing (O5) runs, including the planned upgrades of the Advanced LIGO and Advanced Virgo detectors. We study the capability of the network to determine the sky location of the source for gravitational-wave signals from the inspiral of binary systems of compact objects, that is binary neutron star, neutron star-black hole, and binary black hole systems. The ability to localize the sources is given as a sky-area probability, luminosity distance, and comoving volume. The median sky localization area (90% credible region) is expected to be a few hundreds of square degrees for all types of binary systems during O3 with the Advanced LIGO and Virgo (HLV) network. The median sky localization area will improve to a few tens of square degrees during O4 with the Advanced LIGO, Virgo, and KAGRA (HLVK) network. During O3, the median localization volume (90% credible region) is expected to be on the order of 10 5 , 10 6 , 10 7 Mpc 3 for binary neutron star, neutron star-black hole, and binary black hole systems, respectively. The localization volume in O4 is expected to be about a factor two smaller than in O3. We predict a detection count of 1 - 1 + 12 ( 10 - 10 + 52 ) for binary neutron star mergers, of 0 - 0 + 19 ( 1 - 1 + 91 ) for neutron star-black hole mergers, and 17 - 11 + 22 ( 79 - 44 + 89 ) for binary black hole mergers in a one-calendar-year observing run of the HLV network during O3 (HLVK network during O4). We evaluate sensitivity and localization expectations for unmodeled signal searches, including the search for intermediate mass black hole binary mergers.