The Non-homogeneous Poisson Process for Fast Radio Burst Rates

This paper presents the non-homogeneous Poisson process (NHPP) for modeling the rate of fast radio bursts (FRBs) and other infrequently observed astronomical events. The NHPP, well-known in statistics, can model changes in the rate as a function of both astronomical features and the details of an observing campaign. This is particularly helpful for rare events like FRBs because the NHPP can combine information across surveys, making the most of all available information. The goal of the paper is two-fold. First, it is intended to be a tutorial on the use of the NHPP. Second, we build an NHPP model that incorporates beam patterns and a power law flux distribution for the rate of FRBs. Using information from 12 surveys including 15 detections, we find an all-sky FRB rate of 586.88 events per sky per day above a flux of 1 Jy (95\% CI: 271.86, 923.72) and a flux power-law index of 0.91 (95\% CI: 0.57, 1.25). Our rate is lower than other published rates, but consistent with the rate given in Champion et al. 2016.Comment: 19 pages, 2 figure

Formation and spreading of Red Sea Outflow Water in the Red Sea

Author Posting. © American Geophysical Union, 2015. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 120 (2015): 6542–6563, doi:10.1002/2015JC010751.Hydrographic data, chlorofluorocarbon-12 (CFC-12) and sulfur hexafluoride (SF6) measurements collected in March 2010 and September–October 2011 in the Red Sea, as well as an idealized numerical experiment are used to study the formation and spreading of Red Sea Outflow Water (RSOW) in the Red Sea. Analysis of inert tracers, potential vorticity distributions, and model results confirm that RSOW is formed through mixed-layer deepening caused by sea surface buoyancy loss in winter in the northern Red Sea and reveal more details on RSOW spreading rates, pathways, and vertical structure. The southward spreading of RSOW after its formation is identified as a layer with minimum potential vorticity and maximum CFC-12 and SF6. Ventilation ages of seawater within the RSOW layer, calculated from the partial pressure of SF6 (pSF6), range from 2 years in the northern Red Sea to 15 years at 17°N. The distribution of the tracer ages is in agreement with the model circulation field which shows a rapid transport of RSOW from its formation region to the southern Red Sea where there are longer circulation pathways and hence longer residence time due to basin wide eddies. The mean residence time of RSOW within the Red Sea estimated from the pSF6 age is 4.7 years. This time scale is very close to the mean transit time (4.8 years) for particles from the RSOW formation region to reach the exit at the Strait of Bab el Mandeb in the numerical experiment.King Abdullah University of Science and Technology (KAUST) Grant Numbers: USA 00002, KSA 00011, KSA 00011/02; National Science Foundation; WHOI Academic Program Office Grant Number: OCE09270172016-03-2

A Millisecond Interferometric Search for Fast Radio Bursts with the Very Large Array

We report on the first millisecond timescale radio interferometric search for the new class of transient known as fast radio bursts (FRBs). We used the Very Large Array (VLA) for a 166-hour, millisecond imaging campaign to detect and precisely localize an FRB. We observed at 1.4 GHz and produced visibilities with 5 ms time resolution over 256 MHz of bandwidth. Dedispersed images were searched for transients with dispersion measures from 0 to 3000 pc/cm3. No transients were detected in observations of high Galactic latitude fields taken from September 2013 though October 2014. Observations of a known pulsar show that images typically had a thermal-noise limited sensitivity of 120 mJy/beam (8 sigma; Stokes I) in 5 ms and could detect and localize transients over a wide field of view. Our nondetection limits the FRB rate to less than 7e4/sky/day (95% confidence) above a fluence limit of 1.2 Jy-ms. Assuming a Euclidean flux distribution, the VLA rate limit is inconsistent with the published rate of Thornton et al. We recalculate previously published rates with a homogeneous consideration of the effects of primary beam attenuation, dispersion, pulse width, and sky brightness. This revises the FRB rate downward and shows that the VLA observations had a roughly 60% chance of detecting a typical FRB and that a 95% confidence constraint would require roughly 500 hours of similar VLA observing. Our survey also limits the repetition rate of an FRB to 2 times less than any known repeating millisecond radio transient.Comment: Submitted to ApJ. 13 pages, 9 figure

Seasonal overturning circulation in the Red Sea : 2. Winter circulation

Author Posting. ©0American Geophysical Union, 2014. This article is posted here by permission of [American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 119 (2014): 2263–2289, doi:10.1002/2013JC009331.The shallow winter overturning circulation in the Red Sea is studied using a 50 year high-resolution MITgcm (MIT general circulation model) simulation with realistic atmospheric forcing. The overturning circulation for a typical year, represented by 1980, and the climatological mean are analyzed using model output to delineate the three-dimensional structure and to investigate the underlying dynamical mechanisms. The horizontal model circulation in the winter of 1980 is dominated by energetic eddies. The climatological model mean results suggest that the surface inflow intensifies in a western boundary current in the southern Red Sea that switches to an eastern boundary current north of 24°N. The overturning is accomplished through a cyclonic recirculation and a cross-basin overturning circulation in the northern Red Sea, with major sinking occurring along a narrow band of width about 20 km along the eastern boundary and weaker upwelling along the western boundary. The northward pressure gradient force, strong vertical mixing, and horizontal mixing near the boundary are the essential dynamical components in the model's winter overturning circulation. The simulated water exchange is not hydraulically controlled in the Strait of Bab el Mandeb; instead, the exchange is limited by bottom and lateral boundary friction and, to a lesser extent, by interfacial friction due to the vertical viscosity at the interface between the inflow and the outflow.Partial support for this effort was provided by the Saudi Aramco Marine Environmental Research Center at KAUST.2014-10-1

The Architectural Moment: construction and disruption of the creative process

Beginning an architectural project with the research led detailed development of a threshold using physical models encourages early engagement with material-assembly, disrupting the familiar design process. This exploration of an architectural moment emphasises often overlooked temporal and experiential dimensions of space. This article reflects on eight years of employing the 'architectural moment' as a disruptive learning opportunity, illustrated by student work. Centring technology and materials as integral to studio practice, alongside structured opportunities for reflection, builds student confidence and supports more sophisticated design decision-making, placing ethics, human experience and architectural expression at the heart of the creative process

Yoga for stroke rehabilitation

Background: Stroke is a major health issue and cause of long-term disability and has a major emotional and socioeconomic impact. There is a need to explore options for long-term sustainable interventions that support stroke survivors to engage in meaningful activities to address life challenges after stroke. Rehabilitation focuses on recovery of function and cognition to the maximum level achievable, and may include a wide range of complementary strategies including yoga. Yoga is a mind-body practice that originated in India, and which has become increasingly widespread in the Western world. Recent evidence highlights the positive effects of yoga for people with a range of physical and psychological health conditions. A recent non-Cochrane systematic review concluded that yoga can be used as self-administered practice in stroke rehabilitation. Objectives: To assess the effectiveness of yoga, as a stroke rehabilitation intervention, on recovery of function and quality of life (QoL). Search methods: We searched the Cochrane Stroke Group Trials Register (last searched July 2017), Cochrane Central Register of Controlled Trials (CENTRAL) (last searched July 2017), MEDLINE (to July 2017), Embase (to July 2017), CINAHL (to July 2017), AMED (to July 2017), PsycINFO (to July 2017), LILACS (to July 2017), SciELO (to July 2017), IndMED (to July 2017), OTseeker (to July 2017) and PEDro (to July 2017). We also searched four trials registers, and one conference abstracts database. We screened reference lists of relevant publications and contacted authors for additional information. Selection criteria: We included randomised controlled trials (RCTs) that compared yoga with a waiting-list control or no intervention control in stroke survivors. Data collection and analysis: Two review authors independently extracted data from the included studies. We performed all analyses using Review Manager (RevMan). One review author entered the data into RevMan; another checked the entries. We discussed disagreements with a third review author until consensus was reached. We used the Cochrane 'Risk of bias' tool. Where we considered studies to be sufficiently similar, we conducted a meta-analysis by pooling the appropriate data. For outcomes for which it was inappropriate or impossible to pool quantitatively, we conducted a descriptive analysis and provided a narrative summary. Main results: We included two RCTs involving 72 participants. Sixty-nine participants were included in one meta-analysis (balance). Both trials assessed QoL, along with secondary outcomes measures relating to movement and psychological outcomes; one also measured disability. In one study the Stroke Impact Scale was used to measure QoL across six domains, at baseline and post-intervention. The effect of yoga on five domains (physical, emotion, communication, social participation, stroke recovery) was not significant; however, the effect of yoga on the memory domain was significant (mean difference (MD) 15.30, 95% confidence interval (CI) 1.29 to 29.31, P = 0.03), the evidence for this finding was very low grade. In the second study, QoL was assessed using the Stroke-Specifc QoL Scale; no significant effect was found. Secondary outcomes included movement, strength and endurance, and psychological variables, pain, and disability. Balance was measured in both studies using the Berg Balance Scale; the effect of intervention was not significant (MD 2.38, 95% CI -1.41 to 6.17, P = 0.22). Sensititivy analysis did not alter the direction of effect. One study measured balance self-efficacy, using the Activities-specific Balance Confidence Scale (MD 10.60, 95% CI -7.08,= to 28.28, P = 0.24); the effect of intervention was not significant; the evidence for this finding was very low grade. One study measured gait using the Comfortable Speed Gait Test (MD 1.32, 95% CI -1.35 to 3.99, P = 0.33), and motor function using the Motor Assessment Scale (MD -4.00, 95% CI -12.42 to 4.42, P = 0.35); no significant effect was found based on very low-grade evidence. One study measured disability using the modified Rankin Scale (mRS) but reported only whether participants were independent or dependent. No significant effect was found: (odds ratio (OR) 2.08, 95% CI 0.50 to 8.60, P = 0.31); the evidence for this finding was very low grade. Anxiety and depression were measured in one study. Three measures were used: the Geriatric Depression Scale-Short Form (GCDS15), and two forms of State Trait Anxiety Inventory (STAI, Form Y) to measure state anxiety (i.e. anxiety experienced in response to stressful situations) and trait anxiety (i.e. anxiety associated with chronic psychological disorders). No significant effect was found for depression (GDS15, MD -2.10, 95% CI -4.70 to 0.50, P = 0.11) or for trait anxiety (STAI-Y2, MD -6.70, 95% CI -15.35 to 1.95, P = 0.13), based on very low-grade evidence. However, a significant effect was found for state anxiety: STAI-Y1 (MD -8.40, 95% CI -16.74 to -0.06, P = 0.05); the evidence for this finding was very low grade. No adverse events were reported. Quality of the evidence: We assessed the quality of the evidence using GRADE. Overall, the quality of the evidence was very low, due to the small number of trials included in the review both of which were judged to be at high risk of bias, particularly in relation to incompleteness of data and selective reporting, and especially regarding the representative nature of the sample in one study. Authors' conclusions: Yoga has the potential for being included as part of patient-centred stroke rehabilitation. However, this review has identified insufficient information to confirm or refute the effectiveness or safety of yoga as a stroke rehabilitation treatment. Further large-scale methodologically robust trials are required to establish the effectiveness of yoga as a stroke rehabilitation treatment

Highly ionized gas on galaxy scales: mapping the interacting Seyfert galaxy LEDA 135736

We have used the VIMOS IFU to map the properties of the Seyfert 1.9 galaxy LEDA 135736. These maps reveal a number of interesting features including: an Extended Narrow Line Region detectable out to 9 kpc, an area of intense star formation located at a projected distance of 12 kpc from the centre, an elliptical companion galaxy, and kinematic features, aligned along the long-axis of the ENLR, that are consistent with radio jet-driven mass outflow. We propose that the ENLR results from extra-planar gas ionized by the AGN, and that the AGN in turn might be triggered by interaction with the companion galaxy, which can also explain the burst of star formation and morphological features. Only about two percent of the ENLR's kinetic energy is in the mass outflow. We infer from this that the bulk of mechanical energy imparted by the jet is used to heat this gas.Comment: Accepted for publication in MNRAS Letter

The Canada-UK Deep Submillimetre Survey: First Submillimetre Images, the Source Counts, and Resolution of the Background

We present the first results of a deep unbiased submillimetre survey carried out at 450 and 850 microns. We detected 12 sources at 850 microns, giving a surface density of sources with 850-micron flux densities > 2.8mJy of of 0.49+-0.16 per square arcmin. The sources constitute 20-30% of the background radiation at 850 microns and thus a significant fraction of the entire background radiation produced by stars. This implies, through the connection between metallicity and background radiation, that a significant fraction of all the stars that have ever been formed were formed in objects like those detected here. The combination of their large contribution to the background radiation and their extreme bolometric luminosities make these objects excellent candidates for being proto-ellipticals. Optical astronomers have recently shown that the UV-luminosity density of the universe increases by a factor of about 10 between z=0 and z=1 and then decreases again at higher redshifts. Using the results of a parallel submillimetre survey of the local universe, we show that both the submillimetre source density and background can be explained if the submillimetre luminosity density evolves in a similar way to the UV-luminosity density. Thus, if these sources are ellipticals in the process of formation, they may be forming at relatively modest redshifts.Comment: 8 pages (LATEX), 6 postscript figures, submitted to ApJ Letter

Near-surface transport pathways in the north Atlantic Ocean : looking for throughput from the subtropical to the subpolar gyre

Author Posting. © American Meteorological Society, 2011. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 41 (2011): 911–925, doi:10.1175/2011JPO4498.1.Motivated by discrepancies between Eulerian transport estimates and the behavior of Lagrangian surface drifters, near-surface transport pathways and processes in the North Atlantic are studied using a combination of data, altimetric surface heights, statistical analysis of trajectories, and dynamical systems techniques. Particular attention is paid to the issue of the subtropical-to-subpolar intergyre fluid exchange. The velocity field used in this study is composed of a steady drifter-derived background flow, upon which a time-dependent altimeter-based perturbation is superimposed. This analysis suggests that most of the fluid entering the subpolar gyre from the subtropical gyre within two years comes from a narrow region lying inshore of the Gulf Stream core, whereas fluid on the offshore side of the Gulf Stream is largely prevented from doing so by the Gulf Stream core, which acts as a strong transport barrier, in agreement with past studies. The transport barrier near the Gulf Stream core is robust and persistent from 1992 until 2008. The qualitative behavior is found to be largely independent of the Ekman drift.This work was supported by the National Science Foundation Grants CMG-82469600 and CMG-82579600 and by the Office of Naval Research Grant ONR-13108700

The human red nucleus and lateral cerebellum in supporting roles for sensory information processing

A functional MRI study compared activation in the red nucleus to that in the lateral cerebellar dentate nucleus during passive and active tactile discrimination tasks. The study pursued recent neuroimaging results suggesting that the cerebellum may be more associated with sensory processing than with the control of movement for its own sake. Because the red nucleus interacts closely with the cerebellum, the possibility was examined that activity in red nucleus might also be driven by the requirement for tactile sensory processing with the fingers rather than by finger movement alone. The red and dentate nuclei were about 300% more active (a combination of activation areas and intensities) during passive (non‐motor) tactile stimulation when discrimination was required than when it was not. Thus, the red nucleus was activated by purely sensory stimuli even in the absence of the opportunity to coordinate finger movements or to use the sensory cues to guide movement. The red and dentate nuclei were about 70% more active during active tactile tasks when discrimination was required than when it was not (i.e., for simple finger movements alone). Thus, the red nucleus was most active when the fingers were being used for tactile sensory discrimination. In both the passive and active tactile tasks, the observed activation had a contralateralized pattern, with stronger activation in the left red nucleus and right dentate nucleus. Significant covariation was observed between activity in the red nucleus and the contralateral dentate during the discrimination tasks and no significant correlation between the red nucleus and the contralateral dentate activity was detected during the two non‐discrimination tasks. The observed interregional covariance and contralateralized activation patterns suggest strong functional connectivity during tactile discrimination tasks. Overall, the pattern of findings suggests that the activity in the red nucleus, as in the lateral cerebellum, is more driven by the requirements for sensory processing than by motor coordination per se