Search for Tensor, Vector, and Scalar Polarizations in the Stochastic Gravitational-Wave Background

The detection of gravitational waves with Advanced LIGO and Advanced Virgo has enabled novel tests of general relativity, including direct study of the polarization of gravitational waves. While general relativity allows for only two tensor gravitational-wave polarizations, general metric theories can additionally predict two vector and two scalar polarizations. The polarization of gravitational waves is encoded in the spectral shape of the stochastic gravitational-wave background, formed by the superposition of cosmological and individually unresolved astrophysical sources. Using data recorded by Advanced LIGO during its first observing run, we search for a stochastic background of generically polarized gravitational waves. We find no evidence for a background of any polarization, and place the first direct bounds on the contributions of vector and scalar polarizations to the stochastic background. Under log-uniform priors for the energy in each polarization, we limit the energy densities of tensor, vector, and scalar modes at 95% credibility to Ω0T<5.58×10-8, Ω0V<6.35×10-8, and Ω0S<1.08×10-7 at a reference frequency f0=25 Hz. © 2018 American Physical Society

On the progenitor of binary neutron star merger GW170817

On 2017 August 17 the merger of two compact objects with masses consistent with two neutron stars was discovered through gravitational-wave (GW170817), gamma-ray (GRB 170817A), and optical (SSS17a/AT 2017gfo) observations. The optical source was associated with the early-type galaxy NGC 4993 at a distance of just ∼40 Mpc, consistent with the gravitational-wave measurement, and the merger was localized to be at a projected distance of ∼2 kpc away from the galaxy's center. We use this minimal set of facts and the mass posteriors of the two neutron stars to derive the first constraints on the progenitor of GW170817 at the time of the second supernova (SN). We generate simulated progenitor populations and follow the three-dimensional kinematic evolution from binary neutron star (BNS) birth to the merger time, accounting for pre-SN galactic motion, for considerably different input distributions of the progenitor mass, pre-SN semimajor axis, and SN-kick velocity. Though not considerably tight, we find these constraints to be comparable to those for Galactic BNS progenitors. The derived constraints are very strongly influenced by the requirement of keeping the binary bound after the second SN and having the merger occur relatively close to the center of the galaxy. These constraints are insensitive to the galaxy's star formation history, provided the stellar populations are older than 1 Gyr

Gut bacterial composition in a mouse model of Parkinson's disease

The mechanism of neurodegeneration in Parkinson's disease (PD) remains unknown but it has been hypothesised that the intestinal tract could be an initiating and contributing factor to the neurodegenerative processes. In PD patients as well as in animal models for PD, alpha-synuclein-positive enteric neurons in the colon and evidence of colonic inflammation have been demonstrated. Moreover, several studies reported pro-inflammatory bacterial dysbiosis in PD patients. Here, we report for the first time significant changes in the composition of caecum mucosal associated and luminal microbiota and the associated metabolic pathways in a rotenone-induced mouse model for PD. The mouse model for PD, induced by the pesticide rotenone, is associated with an imbalance in the gut microbiota, characterised by a significant decrease in the relative abundance of the beneficial commensal bacteria genus Bifidobacterium. Overall, intestinal bacterial dysbiosis might play an important role in both the disruption of intestinal epithelial integrity and intestinal inflammation, which could lead or contribute to the observed alpha-synuclein aggregation and PD pathology in the intestine and central nervous system in the oral rotenone mouse model of PD

Gut bacterial composition in a mouse model of Parkinson's disease

The mechanism of neurodegeneration in Parkinson's disease (PD) remains unknown but it has been hypothesised that the intestinal tract could be an initiating and contributing factor to the neurodegenerative processes. In PD patients as well as in animal models for PD, alpha-synuclein-positive enteric neurons in the colon and evidence of colonic inflammation have been demonstrated. Moreover, several studies reported pro-inflammatory bacterial dysbiosis in PD patients. Here, we report for the first time significant changes in the composition of caecum mucosal associated and luminal microbiota and the associated metabolic pathways in a rotenone-induced mouse model for PD. The mouse model for PD, induced by the pesticide rotenone, is associated with an imbalance in the gut microbiota, characterised by a significant decrease in the relative abundance of the beneficial commensal bacteria genus Bifidobacterium. Overall, intestinal bacterial dysbiosis might play an important role in both the disruption of intestinal epithelial integrity and intestinal inflammation, which could lead or contribute to the observed alpha-synuclein aggregation and PD pathology in the intestine and central nervous system in the oral rotenone mouse model of PD

Prolactinomas presenting as primary amenorrhoea and delayed or arrested puberty: response to medical therapy.

Fourteen patients presented with arrested pubertal development associated with prolactin-secreting pituitary tumours; serum prolactin ranged from 4000-104,300 mU/l in the ten females and 920-68,000 in four males. Skull X-ray showed a markedly expanded pituitary fossa in eight patients. CT scan and/or air encephalography showed macroadenomas in nine, of whom seven had large suprasellar extensions to their tumours, yet only five had complained of headache and only two had visual field defects. All were treated with bromocriptine (7.5-60 mg/day) which lowered prolactin substantially in all and into the normal range in 11 (range less than 60-3090, median 105 mU/l). Puberty thereafter progressed spontaneously in 13, but in one patient, whose prolactin did not suppress completely, menarche could be induced only with clomiphene. Anterior pituitary function improved on bromocriptine. In seven patients with macroadenomas, tumour shrinkage into the pituitary fossa was complete and in two others incomplete shrinkage was followed by transsphenoidal hypophysectomy. Seven patients received pituitary irradiation, six after bromocriptine-induced shrinkage and one after transsphenoidal surgery. At follow-up 6 months to 10 years (median 5 years) after presentation, ten remain on bromocriptine with a suppressed serum prolactin, one has a normal prolactin after surgery, and three are off bromocriptine with residual hyperprolactinaemia (418-4680 mU/l). To date, four females have become pregnant and one male has fathered two children. Prolactinomas are an important, albeit rare, cause of arrested puberty and should therefore be sought. Most patients respond well to bromocriptine, with or without pituitary irradiation