Surrogate forward models for population inference on compact binary mergers

Rapidly growing catalogs of compact binary mergers from advanced gravitational-wave detectors allow us to explore the astrophysics of massive stellar binaries. Merger observations can constrain the uncertain parameters that describe the underlying processes in the evolution of stars and binary systems in population models. In this paper, we demonstrate that binary black hole populations - namely, detection rates, chirp masses, and redshifts - can be used to measure cosmological parameters describing the redshift-dependent star formation rate and metallicity distribution. We present a method that uses artificial neural networks to emulate binary population synthesis computer models, and construct a fast, flexible, parallelisable surrogate model that we use for inference.Comment: 16 pages, 3 tables, 8 figure

Variations in the Relationship Between the Frequency Content of EMG Signals and the Rate of Torque Development in Voluntary and Elicited Contractions

Our purpose was to characterize the relationship between EMG mean power frequency (MPF) or median frequency (MF) and rate of torque development in voluntary ballistic and electrically elicited isometric contractions. Twenty-three healthy adults participated in two sets of experiments performed on elbow flexor muscles. For Experiment 1, subjects were asked to generate voluntary ballistic contractions by reaching four different target torque levels (20, 40, 60 and 100% of the maximal voluntary contraction (MVC)) as fast as they could. For Experiment 2, electrical (M-waves) and mechanical (twitches) responses to electrical stimulation of the nerves supplying the biceps brachii and brachioradialis muscles were recorded with the subjects at rest and with a background isometric contraction of 15% MVC. MPF, MF and rate of torque development (% MVC/s) were calculated for both voluntary and elicited contractions. Significant positive correlations were observed between MPF and rate of torque development for the voluntary contractions, whereas significant negative correlations were observed between the two variables for elicited contractions. This suggests that factors other than muscle fiber composition influence the frequency content of EMG signals and/or the rate of torque development, and that the effect of these factors will vary between voluntary and elicited contractions. 2002 Elsevier Science Ltd. All rights reserved

Neuroplasticity and brain repair after stroke.

Purpose of reviewThis review considers recent insights into the neurobiology of repair after stroke in animals and humans, the range of emerging therapies to promote repair and recovery after the acute phase of stroke, and issues related to optimizing trials of such therapies.Recent findingsAnimal studies continue to shed light on the molecular, vascular, glial, neuronal, behavioral, and environmental events that are important to the spontaneous behavioral recovery that is observed during the weeks after a stroke. Animal and human studies are examining a wide range of potential interventions that may favorably modify outcome, including small molecules, growth factors, cell-based approaches, electromagnetic stimulation, a range of devices and robots, and intense physiotherapy methods, including constraint-induced movement therapy. Optimal prescription of these restorative therapies in human patients with stroke requires further study, including defining potential roles for functional neuroimaging.SummaryA wide range of therapies shows promise for improving poststroke brain repair. Insights into the neurobiology of brain repair after stroke in animals and in humans continue to accrue. This information might prove useful in designing and implementing clinical trials that aim to measure the clinical effects of restorative therapies after stroke

Individual and Population Level Resource Selection Patterns of Mountain Lions Preying on Mule Deer along an Urban-Wildland Gradient

Understanding population and individual-level behavioral responses of large carnivores to human disturbance is important for conserving top predators in fragmented landscapes. However, previous research has not investigated resource selection at predation sites of mountain lions in highly urbanized areas. We quantified selection of natural and anthropogenic landscape features by mountain lions at sites where they consumed their primary prey, mule deer (Odocoileus hemionus), in and adjacent to urban, suburban, and rural areas in greater Los Angeles. We documented intersexual and individual-level variation in the environmental conditions present at mule deer feeding sites relative to their availability across home ranges. Males selected riparian woodlands and areas closer to water more than females, whereas females selected developed areas marginally more than males. Females fed on mule deer closer to developed areas and farther from riparian woodlands than expected based on the availability of these features across their home ranges.We suggest that mortality risk for females and their offspring associated with encounters with males may have influenced the different resource selection patterns between sexes. Males appeared to select mule deer feeding sites mainly in response to natural landscape features, while females may have made kills closer to developed areas in part because these are alternative sites where deer are abundant. Individual mountain lions of both sexes selected developed areas more strongly within home ranges where development occurred less frequently. Thus, areas near development may represent a trade-off for mountain lions such that they may benefit from foraging near development because of abundant prey, but as the landscape becomes highly urbanized these benefits may be outweighed by human disturbance

What Constitutes a Successful Result from a Patient Perspective? A Qualitative Analysis

Hypothesis: A patient will deem a surgery successful if they are capable of more mobility after the procedure

Binary population synthesis with probabilistic remnant mass and kick prescriptions

We report on the impact of a probabilistic prescription for compact remnant masses and kicks on massive binary population synthesis. We find that this prescription populates the putative mass gap between neutron stars and black holes with low-mass black holes. However, evolutionary effects reduce the number of X-ray binary candidates with low-mass black holes, consistent with the dearth of such systems in the observed sample. We further find that this prescription is consistent with the formation of heavier binary neutron stars such as GW190425, but over-predicts the masses of Galactic double neutron stars. The revised natal kicks, particularly increased ultra-stripped supernova kicks, do not directly explain the observed Galactic double neutron star orbital period--eccentricity distribution. Finally, this prescription allows for the formation of systems similar to the recently discovered extreme mass ratio binary GW190814, but only if we allow for the survival of binaries in which the common envelope is initiated by a donor crossing the Hertzsprung gap, contrary to our standard model.Comment: Updated version as accepted by MNRA