Axel: A Minimalist Tethered Rover for Exploration of Extreme Planetary Terrains

Recent scientific findings suggest that some of the most interesting sites for future exploration of planetary surfaces lie in terrains that are currently inaccessible to conventional robotic rovers. To provide robust and flexible access to these terrains, we have been developing Axel, the robotic rover. Axel is a lightweight two-wheeled vehicle that can access steep terrains and negotiate relatively large obstacles because of its actively managed tether and novel wheel design. This article reviews the Axel system and focuses on those system components that affect Axel's steep terrain mobility. Experimental demonstrations of Axel on sloped and rocky terrains are presented

Spin-Spin Interactions in Gauge Theory of Gravity, Violation of Weak Equivalence Principle and New Classical Test of General Relativity

For a long time, it is generally believed that spin-spin interactions can only exist in a theory where Lorentz symmetry is gauged, and a theory with spin-spin interactions is not perturbatively renormalizable. But this is not true. By studying the motion of a spinning particle in gravitational field, it is found that there exist spin-spin interactions in gauge theory of gravity. Its mechanism is that a spinning particle will generate gravitomagnetic field in space-time, and this gravitomagnetic field will interact with the spin of another particle, which will cause spin-spin interactions. So, spin-spin interactions are transmitted by gravitational field. The form of spin-spin interactions in post Newtonian approximations is deduced. This result can also be deduced from the Papapetrou equation. This kind of interactions will not affect the renormalizability of the theory. The spin-spin interactions will violate the weak equivalence principle, and the violation effects are detectable. An experiment is proposed to detect the effects of the violation of the weak equivalence principle.Comment: 17 pages, no figur

Discovery of an optical counterpart to the hyperluminous X-ray source in ESO 243-49

The existence of black holes of masses ~ 10^2-10^5 Msun has important implications for the formation and evolution of star clusters and supermassive black holes. One of the strongest candidates to date is the hyperluminous X-ray source HLX1, possibly located in the S0-a galaxy ESO243-49, but the lack of an identifiable optical counterpart had hampered its interpretation. Using the Magellan telescope, we have discovered an unresolved optical source with R = (23.80 +/- 0.25) mag and V = (24.5 +/- 0.3) mag within HLX1's positional error circle. This implies an average X-ray/optical flux ratio ~ 500. Taking the same distance as ESO243-49, we obtain an intrinsic brightness M_R = (-11.0 +/- 0.3) mag, comparable to that of a massive globular cluster. Alternatively, the optical source is consistent with a main-sequence M star in the Galactic halo (for example an M4.4 star at ~ 2.5 kpc). We also examined the properties of ESO243-49 by combining Swift/UVOT observations with stellar population modelling. We found that the overall emission is dominated by a ~5 Gyr old stellar population, but the UV emission at ~2000 Ang is mostly due to ongoing star-formation at a rate of ~ 0.03 Msun/yr. The UV emission is more intense (at least a 9-sigma enhancement above the mean) North East of the nucleus, in the same quadrant as HLX1. With the combined optical and X-ray measurements, we put constraints on the nature of HLX1. We rule out a foreground star and a background AGN. Two alternative scenarios are still viable. HLX1 could be an accreting intermediate-mass black hole in a star cluster, which may itself be the stripped nucleus of a dwarf galaxy that passed through ESO243-49, an event which might have caused the current episode of star formation. Or, it could be a neutron star in the Galactic halo, accreting from an M4-M5 donor star.Comment: 7 pages, accepted by MNRAS. Several improvements from Oct 7 version: stronger evidence of the optical counterpart; more accurate estimate of its brightness (a factor of 2 brighter than previously estimated); use of a larger set of Swift/UVOT data to measure the recent star formation rate in ESO243-49; improved discussion and comparison of the competing scenario

Seeing is Engaging: Vlogs as a Tool for Patient Engagement

Video blogs (‘vlogs’ – pronounced as one syllable) are a popular platform for conveying know-how online and can be used as a tool for patient engagement. It can be challenging to engage patients in their own care, and the unique attributes of vlogs overcome some of the barriers to engagement such as high treatment burden and a lack of the sense of community. While some clinicians may distrust social media and question its place in patient care, we present The Frey Life, one example of a patient vlog, to show how the platform models and fosters engagement, and provides the patient perspective. We discuss potential concerns regarding health vlogs, and suggest implications for physicians, researchers, and medical institutions regarding how to use patient vlogs as a resource

A Unified Framework for the Pareto Law and Matthew Effect using Scale-Free Networks

We investigate the accumulated wealth distribution by adopting evolutionary games taking place on scale-free networks. The system self-organizes to a critical Pareto distribution (1897) of wealth $P(m)\sim m^{-(v+1)}$ with $1.6 < v <2.0$ (which is in agreement with that of U.S. or Japan). Particularly, the agent's personal wealth is proportional to its number of contacts (connectivity), and this leads to the phenomenon that the rich gets richer and the poor gets relatively poorer, which is consistent with the Matthew Effect present in society, economy, science and so on. Though our model is simple, it provides a good representation of cooperation and profit accumulation behavior in economy, and it combines the network theory with econophysics.Comment: 5 pages, 8 figure

Evaluating the reliability, validity and minimally important difference of the Taiwanese version of the diabetes quality of life (DQOL) measurement

<p>Abstract</p> <p>Background</p> <p>Few diabetes HRQOL instruments are available in Chinese language. We tested psychometric properties of a Diabetes Quality of Life (DQOL) in Chinese language for diabetes patients in Taiwan and estimated its minimally important differences (MIDs).</p> <p>Methods</p> <p>Data were collected from 337 patients treated in diabetes clinics of a Taiwan teaching hospital. Pearson's correlations among domain scores of the DQOL (satisfaction, impact, and worry), the D-39S (a diabetes-specific instrument, including domains of diabetes control, energy and mobility, social burden and anxiety and worry, and sexual functioning) and the RAND-12 (a generic instrument, including physical health composite (PHC) and mental health composite (MHC)) were estimated to determine convergent/discriminant validity. Known-groups validity was examined using 2-hour postprandial plasma glucose (2 h PPG), hemoglobin A1c (HbA1c)) and presence of complications (retinopathy, neuropathy, and diabetic foot complications rather than the known groups of cardiovascular and cerebrovascular complications). We used a combined anchor- and distribution-based approach to establish MIDs.</p> <p>Results</p> <p>The DQOL scores were more strongly correlated with the physical domains of the D-39S (diabetes control and energy and mobility) and RAND-12 PHC than psychological domains of the D-39S (social burden, anxiety and worry, and sexual functioning) and RAND-12 MHC. The DQOL showed satisfactory discriminative ability for the known groups of 2 h PPG and HbA1c (effect size (ES) ≥ 0.2) and retinopathy, neuropathy, and diabetic foot complications (ES ≥ 0.3), but less satisfactory for the known groups of cardiovascular and cerebrovascular complications. MIDs for the DQOL domains were 3–5 points for satisfaction, 4–5 points for impact, 6–8 points for worry, and 3–4 points for overall HRQOL.</p> <p>Conclusion</p> <p>We validated a DQOL in Chinese language for diabetes patients in Taiwan and provided MIDs to facilitate the measure of diabetes HRQOL.</p

All together now: findings from a PCORI workshop to align patient-reported outcomes in the electronic health record

In recent years, patient-reported outcomes have become increasingly collected and integrated into electronic health records. However, there are few cross-cutting recommendations and limited guidance available in this rapidly developing research area. Our goal is to report key findings from a 2013 Patient-Centered Outcomes Research Institute workshop on this topic and a summary of actions that followed from the workshop, and present resulting recommendations that address patient, clinical and research/quality improvement barriers to regular use. These findings provide actionable guidance across research and practice settings to promote and sustain widespread adoption of patient-reported outcomes across patient populations, healthcare settings and electronic health record systems

Urban traffic from the perspective of dual graph

In this paper, urban traffic is modeled using dual graph representation of urban transportation network where roads are mapped to nodes and intersections are mapped to links. The proposed model considers both the navigation of vehicles on the network and the motion of vehicles along roads. The road's capacity and the vehicle-turning ability at intersections are naturally incorporated in the model. The overall capacity of the system can be quantified by a phase transition from free flow to congestion. Simulation results show that the system's capacity depends greatly on the topology of transportation networks. In general, a well-planned grid can hold more vehicles and its overall capacity is much larger than that of a growing scale-free network.Comment: 7 pages, 10 figure

Fatness and fitness: how do they influence health-related quality of life in type 2 diabetes mellitus?

<p>Abstract</p> <p>Objective</p> <p>We examined whether adiposity and fitness explain the decrease in health-related quality of life (HRQOL) associated with type 2 diabetes mellitus.</p> <p>Methods</p> <p>This was a cross-sectional study using baseline data from two exercise training interventions. One study enrolled people with and the other without type 2 diabetes. We assessed aerobic fitness ("fitness") as peak oxygen uptake during treadmill testing, adiposity ("fatness") as percentage of total body fat by dual-energy x-ray absorptiometry, and HRQOL by the Medical Outcomes Study SF-36. Bivariate and multivariate linear regression analyses were used examine determinants of HRQOL were used to examine determinants of HRQOL.</p> <p>Results</p> <p>There were 98 participants with and 119 participants without type 2 diabetes. Participants with type 2 diabetes had a mean hemoglobin A1c of 6.6% and, compared with participants without diabetes had lower HRQOL on the physical component summary score (<it>P </it>= 0.004), role-physical (<it>P </it>= 0.035), vitality (<it>P </it>= 0.062) and general health (<it>P </it>< 0.001) scales after adjusting for age, sex and race. These associations of HRQOL with type 2 diabetes were attenuated by higher fitness, even more than reduced fatness. Only general health remained positively associated with type 2 diabetes after accounting for fatness or fitness (<it>P </it>= 0.003). There were no significant differences between participants with and without diabetes in the mental component score.</p> <p>Conclusion</p> <p>Improved fitness, even more than reduced fatness, attenuated the association of type 2 diabetes with HRQOL. The potential to improve HRQOL may motivate patients with type 2 diabetes to engage in physical activity aimed at increasing fitness. Findings from this cross-sectional analysis will be addressed in the ongoing trial of exercise training in this cohort of participants with type 2 diabetes.</p> <p>Trial registration</p> <p>NCT00212303</p

Network Topology of an Experimental Futures Exchange

Many systems of different nature exhibit scale free behaviors. Economic systems with power law distribution in the wealth is one of the examples. To better understand the working behind the complexity, we undertook an empirical study measuring the interactions between market participants. A Web server was setup to administer the exchange of futures contracts whose liquidation prices were coupled to event outcomes. After free registration, participants started trading to compete for the money prizes upon maturity of the futures contracts at the end of the experiment. The evolving `cash' flow network was reconstructed from the transactions between players. We show that the network topology is hierarchical, disassortative and scale-free with a power law exponent of 1.02+-0.09 in the degree distribution. The small-world property emerged early in the experiment while the number of participants was still small. We also show power law distributions of the net incomes and inter-transaction time intervals. Big winners and losers are associated with high degree, high betweenness centrality, low clustering coefficient and low degree-correlation. We identify communities in the network as groups of the like-minded. The distribution of the community sizes is shown to be power-law distributed with an exponent of 1.19+-0.16.Comment: 6 pages, 12 figure