Generalizations of the Abstract Boundary singularity theorem

The Abstract Boundary singularity theorem was first proven by Ashley and Scott. It links the existence of incomplete causal geodesics in strongly causal, maximally extended spacetimes to the existence of Abstract Boundary essential singularities, i.e., non-removable singular boundary points. We give two generalizations of this theorem: the first to continuous causal curves and the distinguishing condition, the second to locally Lipschitz curves in manifolds such that no inextendible locally Lipschitz curve is totally imprisoned. To do this we extend generalized affine parameters from $C^1$ curves to locally Lipschitz curves.Comment: 24 page

Group A: ASME Student Design Challenge

This year\u27s student design competition is termed Building to the Sky. Student teams are required to build a compact engineering system capable of manufacturing a tower made of only standard-sized sheets of paper

Modeling the shape hierarchy for visually guided grasping

The monkey anterior intraparietal area (AIP) encodes visual information about three-dimensional object shape that is used to shape the hand for grasping. We modeled shape tuning in visual AIP neurons and its relationship with curvature and gradient information from the caudal intraparietal area (CIP). The main goal was to gain insight into the kinds of shape parameterizations that can account for AIP tuning and that are consistent with both the inputs to AIP and the role of AIP in grasping. We first experimented with superquadric shape parameters. We considered superquadrics because they occupy a role in robotics that is similar to AIP in that superquadric fits are derived from visual input and used for grasp planning. We also experimented with an alternative shape parameterization that was based on an Isomap dimension reduction of spatial derivatives of depth (i.e., distance from the observer to the object surface). We considered an Isomap-based model because its parameters lacked discontinuities between similar shapes. When we matched the dimension of the Isomap to the number of superquadric parameters, the superquadric model fit the AIP data somewhat more closely. However, higher-dimensional Isomaps provided excellent fits. Also, we found that the Isomap parameters could be approximated much more accurately than superquadric parameters by feedforward neural networks with CIP-like inputs. We conclude that Isomaps, or perhaps alternative dimension reductions of visual inputs to AIP ,provide a promising model of AIP electrophysiology data. Further work is needed to test whether such shape parameterizations actually provide an effective basis for grasp contro

Influence of caffeine on performance, physiological responses, thermoregulation and hydration during a 1500m run in hot humid conditions

Introduction: Caffeine is ergogenic for endurance performance, however little research exists on middle-distance performance, particularly in hot/humid conditions. This study examined caffeine's effects on a 1500 m run in hot/humid conditions. Caffeine was expected to enhance performance and lower plasma potassium concentrations with no effect on hydration or thermoregulation, compared to placebo. Methods: In a randomised, double-blind, crossover design, two testing sessions were completed under hot/humid conditions by seventeen healthy individuals. Participants consumed a carbohydrate-controlled meal and placebo (caffeine-free cola) or caffeine (5 mg/kg in placebo) before the run. Measurements were taken at baseline, following 65 min rest and in the climate chamber before, during and after the run. Urine specific gravity, blood lactate, sweat rate, core temperature [Tcore], skin temperature, heart rate, thermal sensation, thermal comfort and plasma caffeine and potassium were assessed. Data were analysed by two-way ANOVA and Tukey tests (p<0.05). Results: Caffeine had no effect on any variables when compared to placebo except Tcore, plasma potassium and perceived fatigue. Post-exercise Tcore was significantly higher for caffeine. Plasma potassium concentrations were significantly elevated after exercise and significantly lower with caffeine compared to placebo. Fewer participants reported fatigue with caffeine. Conclusions: Caffeine had no negative effects on hydration but did not enhance middle distance performance in hot/humid conditions. Thermoregulation was unaffected by caffeine except for post-exercise Tcore which was significantly higher with caffeine. The lack of performance effect may be attributed to the carbohydrate controlled pre-race meal. The lower potassium levels with caffeine may have contributed to the lower levels of perceived fatigue

P1_10 Delta-V Requirements of Spaceflight

The paper calculates the delta-V requirements to launch a spacecraft into Low Earth Orbit and execute Hohmann transfers to the International Space Station orbit and Geosynchronous Orbit. These were found to be 8.03 kms-1, 0.12 kms-1 and 3.94 kms-1, respectively. The paper also includes researched values for the delta-V requirements to travel to the Moon and Phobos. The paper aims to highlight the fact that delta-V requirements for manoeuvres beyond Low Earth Orbit are considerably lower than achieving Low Earth Orbit.Â

P1_1 Could Bruce Willis Save the World?

The film Armageddon (1998) puts forward the possibility of using a nuclear weapon buried deep within an Earth-bound asteroid to split the asteroid in two, each half clearing opposite sides of the Earth with only relatively minor damage. This article investigates the feasibility of such a plan and shows that even using the largest nuclear weapon made to date, the bomb comes over 9 orders of magnitude short of the yield required

Challenges of Corn Stover Transportation

Stover has the potential to be a very useful byproduct of corn. Corn stover uses: Feedstock for cellulosic ethanol; Fuel source for power plants; Animal bedding. Benefits of corn stover: Inexpensive; Readily available in Iowa. Who can stover benefit? Farmers who can make money by selling stover; Buyers have access to cheap, eco-friendly material

Integrating Green Infrastructure into Urban Planning: Developing Melbourne’s Green Factor Tool

As cities increase in size and density, the ecosystem services supplied by urban greenery and green infrastructure are increasingly vital for sustainable, liveable urban areas. However, retaining and maximising urban greenery in densifying cities is challenging. Governments have critical roles in addressing these challenges through policy development and implementation. While there has been significant attention on the quality and quantity of green space on public land, there is an increasing focus on policy mechanisms for integrating green infrastructure into the private realm, including green roofs, walls, facades, balconies and gardens. As part of City of Melbourne’s efforts to increase greening across the municipality, its 2017 Green Our City Strategic Action Plan includes specific focus on the private realm, and development of regulatory processes for green infrastructure. This article reports on a participatory research project to develop a Green Factor Tool for application to building development proposals in Melbourne. We focus on the transdisciplinary collaborations that brought together contributions from researchers, practitioners, policymakers and designers. We discuss how local research on green space contributions to provision of ecosystem services shaped the design of the tool and provided the tool’s rigorous evidence-base. Finally, we consider the roles of urban planning in retaining and maximising urban green spaces in densifying urban areas

Prevalence and Treatment of Depression and Posttraumatic Stress Disorder among Trauma Patients with Non-neurological Injuries

Background Psychological impairment among injury survivors is well documented. Little is known about the prevalence of treatment of psychological impairment, however. We aimed to determine the proportion of injury survivors treated for depression and post-traumatic stress disorder (PTSD) in the year after injury as well as to determine potential barriers to treatment. Methods Adults (18 and over) admitted to a Level I trauma center with an injury severity score (ISS) greater than 10, but without traumatic brain injury or spinal cord injury were eligible for study inclusion. The Center for Epidemiological Studies-Depression (CES-D) and PTSD CheckList – Civilian Versions (PCL-C) surveys were administered during the initial hospitalization and repeated at 1, 2, 4, and 12 months after injury. Patients were asked if they received treatment specifically for depression or PTSD at each follow-up. Factors associated with treatment were determined using multivariable logistic regression analysis. Results 500 injury survivors were enrolled in this prospective observational study. Of those, 68.4% of patients screened positive for depression at some point in the year after their injury (53.3% 1 month, 49.9% 2 month, 49.0% 4 month, and 50.2% 12 month). Only 22.2% of depressed patients reported receiving treatment for depression. 44.4% of patients screened positive for PTSD (26.6% 1 month, 27.8% 2 month, 29.8% 4 month, and 30.0% 12 month), but only 9.8% received treatment for PTSD. After adjusting for other factors, compared to commercial insurance status, self-pay insurance status was negatively associated with treatment for PTSD or depression (OR 0.44, 95% CI 0.21-0.95). Conclusion Depression and PTSD are common in non-neurotrauma patients in the year following injury. Greater collaboration between those caring for injury survivors and behavioral health experts may help improve psychological outcomes after injury