As-Flown Shuttle Micro-Meteoroid Orbital Debris (MMOD) Assessment History

The final flight of the Space Shuttle program was completed on July 21st of 2011. The reusable nature of the Orbiter vehicles has provided NASA with a unique opportunity to inspect and sample spacecraft surfaces exposed to the MMOD environment in low Earth orbit. This paper will provide details of MMOD damages found on Orbiter surfaces after recent flights, as well as putting these damages in context by providing historical comparisons of recent damage to previous flights. The Bumper threat assessment computer code is used by NASA to determine spacecraft MMOD penetration risk. The tool was used before each mission to estimate pre-flight MMOD risk for the Shuttle Program Office using planned vehicles attitudes and exposure times. This paper summarizes the efforts of the authors to assess the expected number MMOD impacts of selected particles sizes of 52 shuttle missions ranging from STS-50 (1992) through STS-133 (2011) using as-flown attitude data. The missions encompass the Shuttle/Mir precursors to the International Space Station (ISS) as well as the ISS assembly flights. The paper includes a comparison of observed MMOD impact damage to the predicted number of impacts from Bumper code assessments. This data can be used to validate engineering models of the orbital debris and micrometeoroid environment, such NASA s ORDEM debris model and MEM meteoroid model

Micrometeoroid and Orbital Debris Threat Mitigation Techniques for the Space Shuttle Orbiter

An overview of significant Micrometeoroid and Orbital Debris (MMOD) impacts on the Payload Bay Door radiators, wing leading edge reinforced carbon-carbon panels and crew module windows will be presented, along with a discussion of the techniques NASA has implemented to reduce the risk from MMOD impacts. The concept of "Late Inspection" of the Nose Cap and Wing leading Edge (WLE) Reinforced Carbon Carbon (RCC) regions will be introduced. An alternative mated attitude with the International Space Station (ISS) on shuttle MMOD risk will also be presented. The significant threat mitigation effect of these two techniques will be demonstrated. The wing leading edge impact detection system, on-orbit repair techniques and disabled vehicle contingency plans will also be discussed

Using behavioral studies to adapt management decisions and reduce negative interactions between humans and baboons in Cape Town, South Africa

Understanding the behavioral ecology of wildlife that experiences negative interactions with humans and the outcome of any wildlife management intervention is essential. In the Cape Peninsula, South Africa, chacma baboons (Papio ursinus) search for anthropogenic food sources in both urban and agricultural areas. In response, the city of Cape Town and private farmers employ “rangers” to keep baboons within the Table Mountain National Park. In this study, we investigated the success of rangers' intervention in keeping baboons in their natural habitat. Based on our findings in year one, we recommended adjustments to the rangers' management strategy in year two. We recommended improved consensus of actions toward baboons (that is, when/where to herd them), and the construction of a baboon-proof fence around one of the farms that provided a corridor to urban areas. During the 2 months following recommendations, these interventions combined resulted in a significant reduction in the time baboons spent in both urban and agricultural land. Our case study illustrates the importance of integrating research findings into ongoing management actions to improve both human livelihoods and baboon conservation through an adaptive management framework. We expect similar approaches to be beneficial in a wide range of species and contexts

Autonomous surgical robotic systems and the liability dilemma

Background: Advances in machine learning and robotics have allowed the development of increasingly autonomous robotic systems which are able to make decisions and learn from experience. This distribution of decisionmaking away from human supervision poses a legal challenge for determining liability. Methods: The iRobotSurgeon survey aimed to explore public opinion towards the issue of liability with robotic surgical systems. The survey included five hypothetical scenarios where a patient comes to harm and the respondent needs to determine who they believe is most responsible: the surgeon, the robot manufacturer, the hospital, or another party. Results: A total of 2,191 completed surveys were gathered evaluating 10,955 individual scenario responses from 78 countries spanning 6 continents. The survey demonstrated a pattern in which participants were sensitive to shifts from fully surgeon-controlled scenarios to scenarios in which robotic systems played a larger role in decision-making such that surgeons were blamed less. However, there was a limit to this shift with human surgeons still being ascribed blame in scenarios of autonomous robotic systems where humans had no role in decision-making. Importantly, there was no clear consensus among respondents where to allocate blame in the case of harm occurring from a fully autonomous system. Conclusions: The iRobotSurgeon Survey demonstrated a dilemma among respondents on who to blame when harm is caused by a fully autonomous surgical robotic system. Importantly, it also showed that the surgeon is ascribed blame even when they have had no role in decision-making which adds weight to concerns that human operators could act as “moral crumple zones” and bear the brunt of legal responsibility when a complex autonomous system causes harm

GHTD-amide : A naturally occurring beta cell-derived peptide with hypoglycemic activity

in the early 1970s, a peptide fraction with insulin potentiating activity was purified from human urine but the identity and origins of the active constituent remained unknown. Here we identify the active component and characterize its origins. The active peptide was identified as an alpha amidated tetrapeptide with the sequence GHTD-amide. The peptide was synthesized and tested for stimulation of glycogen synthesis and insulin potentiation by insulin tolerance testing in insulin-deficient rats, which confirmed GHTD-amide as the active peptide. Tissue localization using a peptide-specific anti-serum and epifluorescent and confocal microscopy showed decoration of pancreatic islets but not other tissues. Confocal microscopy revealed co-localization with insulin and immunogold and electron microscopy showed localization to dense core secretory granules. Consistent with these observations GHTD-amide was found in media conditioned by MIN6 islet beta cells. Sequence database searching found no annotated protein in the human proteome encoding a potential precursor for GHTD-amide. We conclude that the insulin potentiating activity originally described in human urine is attributable to the tetrapeptide GHTD-amide. GHTD-amide is a novel peptide produced by pancreatic beta cells and no precursor protein is present in the annotated human proteome. Stimulation of glycogen synthesis and co-localization with insulin in beta cells suggest that GHTD-amide may play a role in glucose homeostasis by enhancing insulin action and glucose storage in tissues. (C) 2008 Elsevier Inc. All rights reserved

Production and electrical characterization of the reflectin A2 isoform from Doryteuthis (Loligo) pealeii

Cephalopods have recently emerged as a source of inspiration for the development of novel functional materials. Within this context, a number of studies have explored structural proteins known as reflectins, which play a key role in cephalopod adaptive coloration in vivo and exhibit interesting properties in vitro. Herein, we report an improved high-yield strategy for the preparation and isolation of reflectins in quantities sufficient for materials applications. We first select the Doryteuthis (Loligo) pealeii reflectin A2 (RfA2) isoform as a “model” system and validate our approach for the expression and purification of this protein. We in turn fabricate RfA2-based two-terminal devices and employ both direct and alternating current measurements to demonstrate that RfA2 films conduct protons. Our findings underscore the potential of reflectins as functional materials and may allow a wider range of researchers to investigate their properties

Production and electrical characterization of the reflectin A2 isoform from Doryteuthis (Loligo) pealeii

Cephalopods have recently emerged as a source of inspiration for the development of novel functional materials. Within this context, a number of studies have explored structural proteins known as reflectins, which play a key role in cephalopod adaptive coloration in vivo and exhibit interesting properties in vitro. Herein, we report an improved high-yield strategy for the preparation and isolation of reflectins in quantities sufficient for materials applications. We first select the Doryteuthis (Loligo) pealeii reflectin A2 (RfA2) isoform as a “model” system and validate our approach for the expression and purification of this protein. We in turn fabricate RfA2-based two-terminal devices and employ both direct and alternating current measurements to demonstrate that RfA2 films conduct protons. Our findings underscore the potential of reflectins as functional materials and may allow a wider range of researchers to investigate their properties

The NANOGrav Nine-year Data Set:Astrometric Measurements of 37 Millisecond Pulsars

Using the nine-year radio-pulsar timing data set from the North American Nanohertz Observatory for Gravitational Waves (NANOGrav), collected at Arecibo Observatory and the Green Bank Telescope, we have measured the positions, proper motions, and parallaxes for 37 millisecond pulsars. We report twelve significant parallax measurements and distance measurements, and eighteen lower limits on distance. We compare these measurements to distances predicted by the NE2001 interstellar electron density model and find them to be in general agreement. We use measured orbital-decay rates and spin-down rates to confirm two of the parallax distances and to place distance upper limits on other sources; these distance limits agree with the parallax distances with one exception, PSR. J1024-0719, which we discuss at length. Using the proper motions of the 37 NANOGrav pulsars in combination with other published measurements, we calculate the velocity dispersion of the millisecond pulsar population in Galactocentric coordinates. We find the radial, azimuthal, and perpendicular dispersions to be 46, 40, and 24 km s(-1), respectively, in a model that allows for high-velocity outliers; or 81, 58, and 62 km s(-1) for the full population. These velocity dispersions are far smaller than those of the canonical pulsar population, and are similar to older Galactic disk populations. This suggests that millisecond pulsar velocities are largely attributable to their being an old population rather than being artifacts of their birth and evolution as neutron star binary systems. The components of these velocity dispersions follow similar proportions to other Galactic populations, suggesting that our results are not biased by selection effects

Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy