XMM-Newton Archival Study of the ULX Population in Nearby Galaxies

We present the results of an archival XMM-Newton study of the bright X-ray point sources (L_X > 10^38 erg/s) in 32 nearby galaxies. From our list of approximately 100 point sources, we attempt to determine if there is a low-state counterpart to the Ultraluminous X-ray (ULX) population, searching for a soft-hard state dichotomy similar to that known for Galactic X-ray binaries and testing the specific predictions of the IMBH hypothesis. To this end, we searched for "low-state" objects, which we defined as objects within our sample which had a spectrum well fit by a simple absorbed power law, and "high-state" objects, which we defined as objects better fit by a combined blackbody and a power law. Assuming that ``low-state'' objects accrete at approximately 10% of the Eddington luminosity (Done & Gierlinski 2003) and that "high-state" objects accrete near the Eddington luminosity we further divided our sample of sources into low and high state ULX sources. We classify 16 sources as low-state ULXs and 26 objects as high-state ULXs. As in Galactic black hole systems, the spectral indices, Gamma, of the low-state objects, as well as the luminosities, tend to be lower than those of the high-state objects. The observed range of blackbody temperatures for the high state is 0.1-1 keV, with the most luminous systems tending toward the lowest temperatures. We therefore divide our high-state ULXs into candidate IMBHs (with blackbody temperatures of approximately 0.1 keV) and candidate stellar mass BHs (with blackbody temperatures of approximately 1.0 keV). A subset of the candidate stellar mass BHs have spectra that are well-fit by a Comptonization model, a property similar of Galactic BHs radiating in the "very-high" state near the Eddington limit.Comment: 54 pages, submitted to ApJ (March 2005), accepted (May 2006); changes to organization of pape

Effects of age on strength and morphology of toe flexor muscles

Study Design: Cross-sectional. 27 Objective: To compare the strength and size of the toe flexor muscles of older adults relative 28 to their younger counterparts. 29 Background: Age related muscle atrophy is common in lower limb muscles and we therefore 30 speculated that foot muscles also diminish with age. However, there is a paucity of literature 31 characterizing foot muscle strength and morphology, and any relationship between these two, 32 in older people. 33 Methods: Seventeen young adults with a normal foot type were matched by gender and BMI 34 to 17 older adults with a normal foot type, from an available sample of 41 young (18-50 35 years) and 44 older (60+ years) adults. Among the matched groups (n=34), muscle thickness 36 and cross-sectional area (CSA) for five intrinsic and two extrinsic toe flexor muscles were 37 obtained using ultrasound. Toe strength was assessed using a pressure platform. Differences 38 in toe flexor strength and muscle size between the young and older matched groups were 39 determined using ANCOVA (controlling for height). Correlations between strength and size 40 of the toe flexor muscles of the pooled group (n=34) were also calculated. 41 Results: Toe strength and the thickness and CSA of most foot muscles and were significantly 42 reduced in the older adults (P<0.05). Hallux and toe flexor strength were strongly correlated 43 with the size of the intrinsic muscles toe flexor muscles. 44 Conclusion: The smaller foot muscles appear to be affected by sarcopenia in older adults. 45 This could contribute to reduced toe flexion force production and affect the ability of older 46 people to walk safely. Interventions aimed at reversing foot muscle atrophy in older people 47 require further investigation

Measuring Circadian Advantage in Major League Baseball: A 10-Year Retrospective Study

Purpose: The effect of travel on athletic performance has been investigated in previous studies. The purpose of this study was to investigate this effect on game outcome over 10 Major League Baseball (MLB) seasons. Methods: Using the convention that for every time zone crossed, synchronization requires 1 d, teams were assigned a daily number indicating the number of days away from circadian resynchronization. With these values, wins and losses for all games could be analyzed based on circadian values. Results: 19,079 of the 24,121 games (79.1%) were played between teams at an equal circadian time. The remaining 5,042 games consisted of teams playing at different circadian times. The team with the circadian advantage won 2,620 games (52.0%, P = .005), a winning percentage that exceeded chance but was a smaller effect than home field advantage (53.7%, P &lt; .0001). When teams held a 1-h circadian advantage, winning percentage was 51.7% (1,903-1,781). Winning percentage with a 2-h advantage was 51.8% (620-578) but increased to 60.6% (97-63) with a 3-h advantage (3-h advantage &gt; 2-hadvantage = 1-h advantage, P = .036). Direction of advantage showed teams traveling from Western time zones to Eastern time zones were more likely to win (winning percentage = .530) than teams traveling from Eastern time zones to Western time zones (winning percentage = .509) with a winning odds 1.14 (P = .027). Conclusion: These results suggest that in the same way home field advantage influences likelihood of success, so too does the magnitude and direction of circadian advantage. Teams with greater circadian advantage were more likely to win

Development of a Village-Scale, Solar-Powered Reverse Osmosis System

This paper details the development of a photovoltaic reverse osmosis water desalination system for a groundwater well in Bercy, Haiti. The well was constructed to provide potable drinking and agricultural water for the 300-person community. However, its water has a salinity level of 5,290 ppm, rendering it harmful for both human consumption and soil fertility. This reverse osmosis system is designed to be low-cost and operational off-grid while providing 900 gallons per day of desalinated water for the community. The system is composed of a photovoltaic power system, a submersible solar pump, and three reverse osmosis membranes. The system is designed to have a material cost significantly below that of any commercially-available system of similar scale. Furthermore, it has an average water production cost of $1.21/m3 and an average specific energy of 1.2 kWh/m3. Its performance was tested in the laboratory by connecting the desalination module to a DC power supply, demonstrating good agreement with its modeled performance. The installation of the full system with the PV module will take place on-site in the summer of 2016. Following implementation, the system will be monitored and compared against predicted performance. The first attempt is meant to serve as a verification and validation of the system as a whole. However, successful operation within the given cost target could pave the way for wider use of off-grid reverse osmosis systems at many remote locations with limited freshwater access around the world.Massachusetts Institute of Technology. Tata Center for Technology and Desig

Humanized Foxp2 accelerates learning by enhancing transitions from declarative to procedural performance

The acquisition of language and speech is uniquely human, but how genetic changes might have adapted the nervous system to this capacity is not well understood. Two human-specific amino acid substitutions in the transcription factor forkhead box P2 (FOXP2) are outstanding mechanistic candidates, as they could have been positively selected during human evolution and as FOXP2 is the sole gene to date firmly linked to speech and language development. When these two substitutions are introduced into the endogenous Foxp2 gene of mice (Foxp2[superscript hum]), cortico-basal ganglia circuits are specifically affected. Here we demonstrate marked effects of this humanization of Foxp2 on learning and striatal neuroplasticity. Foxp2[superscript hum/hum] mice learn stimulus–response associations faster than their WT littermates in situations in which declarative (i.e., place-based) and procedural (i.e., response-based) forms of learning could compete during transitions toward proceduralization of action sequences. Striatal districts known to be differently related to these two modes of learning are affected differently in the Foxp2[superscript hum/hum] mice, as judged by measures of dopamine levels, gene expression patterns, and synaptic plasticity, including an NMDA receptor-dependent form of long-term depression. These findings raise the possibility that the humanized Foxp2 phenotype reflects a different tuning of corticostriatal systems involved in declarative and procedural learning, a capacity potentially contributing to adapting the human brain for speech and language acquisition.Nancy Lurie Marks Family FoundationSimons Foundation (Autism Research Initiative Grant 137593)National Institutes of Health (U.S.) (Grant R01 MH060379)Wellcome Trust (London, England) (Grant 075491/Z/04)Wellcome Trust (London, England) (Grant 080971)Fondation pour la recherche medicaleMax Planck Society for the Advancement of Scienc

The uptake of soluble and nanoparticulate imaging isotope in model liver tumours after intra-venous and intra-arterial administration

Delivery of chemotherapeutic drugs to tumours by reformulation as nanoparticles has often been proposed as a means of facilitating increased selective uptake, exploiting the increased permeability of the tumour vasculature. However realisation of this improvement in drug delivery in cancer patients has met with limited success. We have compared tumour uptake of soluble Tc99m-pertechnetate and a colloid of nanoparticles with a Tc99m core, using both intra-venous and intra-arterial routes of administration in a rabbit liver VX2 tumour model. The radiolabelled nanoparticles were tested both in untreated and cationised form. The results from this tumour model in an internal organ show a marked advantage in intra-arterial administration over the intra-venous route, even for the soluble isotope. Tumour accumulation of nanoparticles from arterial administration was augmented by cationisation of the nanoparticle surface with histone proteins, which consistently facilitated selective accumulation within microvessels at the periphery of tumours.Sources of support for this research: Sirtex Medical Ltd, Sydney Australia

Effects of Persuasive Dialogues: Testing Bot Identities and Inquiry Strategies

Intelligent conversational agents, or chatbots, can take on various identities and are increasingly engaging in more human-centered conversations with persuasive goals. However, little is known about how identities and inquiry strategies influence the conversation's effectiveness. We conducted an online study involving 790 participants to be persuaded by a chatbot for charity donation. We designed a two by four factorial experiment (two chatbot identities and four inquiry strategies) where participants were randomly assigned to different conditions. Findings showed that the perceived identity of the chatbot had significant effects on the persuasion outcome (i.e., donation) and interpersonal perceptions (i.e., competence, confidence, warmth, and sincerity). Further, we identified interaction effects among perceived identities and inquiry strategies. We discuss the findings for theoretical and practical implications for developing ethical and effective persuasive chatbots. Our published data, codes, and analyses serve as the first step towards building competent ethical persuasive chatbots.Comment: 15 pages, 10 figures. Full paper to appear at ACM CHI 202

Comparing the digital footprint of pulmonary and critical care conferences on Twitter

Background: Pulmonary and critical care societies, including the American Thoracic Society, the American College of Chest Physicians, and the Society of Critical Care Medicine have large memberships that gather at academic conference events, attracting thousands of attendees. Objective: With the growth of social media use among pulmonary and critical care clinicians, our goal was to examine the Twitter presence and digital footprint of these three major medical society conferences. Methods: We used Symplur Signals (Symplur, LLC) to track the tweets and most active participants of the 2017–2019 annual conferences of American Thoracic Society, American College of Chest Physicians, and the Society of Critical Care Medicine. Attendance records of participants were obtained from each society. Results: During the study period, there was growth in the number of tweets, participants, and impressions for all three society conferences. Across all conferences, the amount of original content generated was less than the retweets, which comprised 50–72% of all tweets. Individuals physically attending each conference were more likely to post original content than those not in attendance (53–68% vs. 32–47%). For each society and at each meeting, clinicians made up the largest group of participants (44–60%), and most (59–82%) were physicians. A small cohort of participants was responsible for a large share of the tweets, with more than half of the participants at each conference for each society tweeting only once and only between 5–8% of participants tweeting more than 10 times. Seventy-eight individuals tweeted more than 100 times at one or more of the conferences. There was significant overlap in this group, with 32 of these individual participants tweeting more than 100 times at two or more of these conferences. Conclusion: Growth in conference digital footprints is largely due to increased activity by a small group of prolific participants that attend conferences by multiple academic societies. Original content makes up the smallest proportion of posts, suggesting that amplification of content is more prevalent than posting of original content. In a postpandemic environment, engagement of users producing original content may be even more important for medical societies

Coupled impacts of climate and land use change across a river-lake continuum: Insights from an integrated assessment model of Lake Champlain\u27s Missisquoi Basin, 2000-2040

Global climate change (GCC) is projected to bring higher-intensity precipitation and higher-variability temperature regimes to the Northeastern United States. The interactive effects of GCC with anthropogenic land use and land cover changes (LULCCs) are unknown for watershed level hydrological dynamics and nutrient fluxes to freshwater lakes. Increased nutrient fluxes can promote harmful algal blooms, also exacerbated by warmer water temperatures due to GCC. To address the complex interactions of climate, land and humans, we developed a cascading integrated assessment model to test the impacts of GCC and LULCC on the hydrological regime, water temperature, water quality, bloom duration and severity through 2040 in transnational Lake Champlain\u27s Missisquoi Bay. Temperature and precipitation inputs were statistically downscaled from four global circulation models (GCMs) for three Representative Concentration Pathways. An agent-based model was used to generate four LULCC scenarios. Combined climate and LULCC scenarios drove a distributed hydrological model to estimate river discharge and nutrient input to the lake. Lake nutrient dynamics were simulated with a 3D hydrodynamic-biogeochemical model. We find accelerated GCC could drastically limit land management options to maintain water quality, but the nature and severity of this impact varies dramatically by GCM and GCC scenario