An Autonomous Flight Safety System

The Autonomous Flight Safety System (AFSS) being developed by NASA s Goddard Space Flight Center s Wallops Flight Facility and Kennedy Space Center has completed two successful developmental flights and is preparing for a third. AFSS has been demonstrated to be a viable architecture for implementation of a completely vehicle based system capable of protecting life and property in event of an errant vehicle by terminating the flight or initiating other actions. It is capable of replacing current human-in-the-loop systems or acting in parallel with them. AFSS is configured prior to flight in accordance with a specific rule set agreed upon by the range safety authority and the user to protect the public and assure mission success. This paper discusses the motivation for the project, describes the method of development, and presents an overview of the evolving architecture and the current status

Comparison of Haseman-Elston regression analyses using single, summary, and longitudinal measures of systolic blood pressure

To compare different strategies for linkage analyses of longitudinal quantitative trait measures, we applied the "revisited" Haseman-Elston (RHE) regression model (the cross product of centered sib-pair trait values is regressed on expected identical-by-descent allele sharing) to cross-sectional, summary, and repeated measurements of systolic blood pressure (SBP) values in replicate 34, randomly selected from the Genetic Analysis Workshop 13 simulated data. RHE linkage scans were performed without knowledge of the generating model using the following phenotypes derived from untreated SBP measurements: the first, the last, the mean, the ratio of the change between the first and last over time, and the estimated linear regression slope coefficient. Estimates of allele sharing in sibling pairs were obtained from the complete genotype data of Cohorts 1 and 2, but linkage analyses were restricted to the five visits of Cohort 2 siblings. Evidence for linkage was suggestive (p < 0.001) at markers neighboring SBP genes Gb35, Gs10, and Gs12, but weaker signals (p < 0.01) were obtained at markers mapping close to Gb34 and Gs11. Linkage to baseline genes Gb34 and Gb35 was best detected using the first SBP measurement, whereas linkage to slope genes Gs10-12 was best detected using the last or mean SBP value. At markers on chromosomes 13 and 21 displaying strongest linkage signals, marginal RHE-type models including repeated SBP measures were fit to test for overall and time-dependent genetic effects. These analyses assumed independent sib pairs and employed generalized estimating equations (GEE) with a first-order autoregressive working correlation structure to adjust for serial correlation present among repeated observations from the same sibling pair

Small Rocket/Spacecraft Technology (SMART) Platform

The NASA Goddard Space Flight Center (GSFC) and the Department of Defense Operationally Responsive Space (ORS) Office are exercising a multi-year collaborative agreement focused on a redefinition of the way space missions are designed and implemented. A much faster, leaner and effective approach to space flight requires the concerted effort of a multi-agency team tasked with developing the building blocks, both programmatically and technologically, to ultimately achieve flights within 7-days from mission call-up. For NASA, rapid mission implementations represent an opportunity to find creative ways for reducing mission life-cycle times with the resulting savings in cost. This in tum enables a class of missions catering to a broader audience of science participants, from universities to private and national laboratory researchers. To that end, the SMART (Small Rocket/Spacecraft Technology) micro-spacecraft prototype demonstrates an advanced avionics system with integrated GPS capability, high-speed plug-and-playable interfaces, legacy interfaces, inertial navigation, a modular reconfigurable structure, tunable thermal technology, and a number of instruments for environmental and optical sensing. Although SMART was first launched inside a sounding rocket, it is designed as a free-flyer

Predators reduce extinction risk in noisy metapopulations

Background Spatial structure across fragmented landscapes can enhance regional population persistence by promoting local “rescue effects.” In small, vulnerable populations, where chance or random events between individuals may have disproportionately large effects on species interactions, such local processes are particularly important. However, existing theory often only describes the dynamics of metapopulations at regional scales, neglecting the role of multispecies population dynamics within habitat patches. Findings By coupling analysis across spatial scales we quantified the interaction between local scale population regulation, regional dispersal and noise processes in the dynamics of experimental host-parasitoid metapopulations. We find that increasing community complexity increases negative correlation between local population dynamics. A potential mechanism underpinning this finding was explored using a simple population dynamic model. Conclusions Our results suggest a paradox: parasitism, whilst clearly damaging to hosts at the individual level, reduces extinction risk at the population level

Fluorescence based Tool to Detect Endogenous Peroxynitrite in M1-Polarized Murine J774.2 Macrophages

Oxidative stress and inflammation are intrinsically linked to each other. In addition, they are implicated in the evolution and progression of noncommunicable diseases (NCDs). Large amounts of reactive oxygen species (ROS) are generated as part of the immune response toward NCDs. Among all of the ROS species, peroxynitrite (ONOO^–) has the shortest half-life with <20 ms under typical physiological conditions. Hence, detecting ONOO^– and studying its generation in vitro allows for a better understanding of inflammatory processes. We demonstrate that peroxyresorufin-1 (PR1) is a selective and sensitive ONOO^– fluorescence-based sensor in J774.2 macrophages. PR1 was able to detect changes in ONOO^– production upon investigation of different factors: enhanced generation of ONOO^– through LPS and IFN-γ as well as diminished ONOO^– production with the introduction of superoxide scavengers and nitric oxide synthase inhibitors. Our study validates PR1 as an effective tool for the detection of ONOO^– in J774.2 murine macrophages and should allow for further elucidation of ROS biology and chemistry

Effect of Ventilation Rate on Instilled Surfactant Distribution in the Pulmonary Airways of Rats

Liquid can be instilled into the pulmonary airways during medical procedures such as surfactant replacement therapy, partial liquid ventilation, and pulmonary drug delivery. For all cases, understanding the dynamics of liquid distribution in the lung will increase the efficacy of treatment. A recently developed imaging technique for the study of real-time liquid transport dynamics in the pulmonary airways was used to investigate the effect of respiratory rate on the distribution of an instilled liquid, surfactant, in a rat lung. Twelve excised rat lungs were suspended vertically, and a single bolus (0.05 ml) of exogenous surfactant (Survanta, Ross Laboratories, Columbus, OH) mixed with radiopaque tracer was instilled as a plug into the trachea. The lungs were ventilated with a 4-ml tidal volume for 20 breaths at one of two respiratory rates: 20 or 60 breaths/min. The motion of radiodense surfactant was imaged at 30 frames/s with a microfocal X-ray source and an image intensifier. Dynamics of surfactant distribution were quantified for each image by use of distribution statistics and a homogeneity index. We found that the liquid distribution depended on the time to liquid plug rupture, which depends on ventilation rate. At 20 breaths/min, liquid was localized in the gravity-dependent region of the lung. At 60 breaths/min, the liquid coated the airways, providing a more vertically uniform liquid distribution

A new Holocene record of geomagnetic secular variation from Windermere, UK

Paleomagnetic secular variation (PSV) records serve as valuable independent stratigraphic correlation and dating tools for marine and terrestrial sediment sequences, and enhance knowledge of geomagnetic field dynamics. We present a new radiocarbon-dated record (WINPSV-12K) of Holocene geomagnetic secular variation from Windermere, updating the existing 1981 UK master PSV curve. Our analyses used continuous U-channel samples taken from the center of four sediment cores retrieved from Windermere in 2012. The natural remanent magnetization (NRM) of each U-channel was measured before and after stepwise alternating field (AF) demagnetization on a superconducting rock magnetometer at intervals of 0.5-cm or 1-cm. The NRM data reveal a stable and well-defined primary magnetization. Component declinations and inclinations estimated using Principal Component Analysis (PCA) of NRM data from the four Windermere cores correlate well on their independent radiocarbon age models. The four records were stacked using a sliding window bootstrap method, resulting in a composite Holocene PSV record (WINPSV-12K). On millennial timescales WINPSV-12K correlates well with other records from Western Europe and the northern North Atlantic to a resolution of ∼ 1 kyr, given age uncertainties and spatial variability between records. WINPSV-12K also compares well to the CALS10k.2 and pfm9k.1a model predictions for Windermere. Key regionally-significant PSV inclination features of WINPSV-12K which correlate with other North Atlantic records include peaks at 5–6, 8.5, and 10 cal ka BP, and a trough at 7calkaBP. Key PSV declination features include the eastward swing from 5.5–2.3 cal ka BP followed by a major westward excursion at 2.3 cal ka BP, peaks at 1.1 and 7calkaBP, and troughs at 5.4 and 8.2 cal ka BP, with the caveat that an estimated magnetic lock-in delay of at least 100–200 yr is present. PSV variations on 1–3 kyr timescales are interpreted to represent strengthening and weakening of the North American versus the Siberian and European–Mediterranean high-latitude flux lobes, based on the close similarities between the North Atlantic regional records and the antiphase existing in the East Asian Stack record and the North East Pacific inclination stack. WINPSV-12K provides a regionally-important new PSV reference curve whose prominent features may serve as stratigraphic markers for North Atlantic paleo-records

The influence of refuge sharing on social behaviour in the lizard Tiliqua rugosa

Refuge sharing by otherwise solitary individuals during periods of inactivity is an integral part of social behaviour and has been suggested to be the precursor to more complex social behaviour. We compared social association patterns of active versus inactive sheltering individuals in the social Australian sleepy lizard, Tiliqua rugosa, to empirically test the hypothesis that refuge sharing facilitates social associations while individuals are active. We fitted 18 neighbouring lizards with Global Positioning System (GPS) recorders to continuously monitor social associations among all individuals, based on location records taken every 10 min for 3 months. Based on these spatial data, we constructed three weighted, undirected social networks. Two networks were based on empirical association data (one for active and one for inactive lizards in their refuges), and a third null model network was based on hypothetical random refuge sharing. We found patterns opposite to the predictions of our hypothesis. Most importantly, association strength was higher in active than in inactive sheltering lizards. That is, individual lizards were more likely to associate with other lizards while active than while inactive and in shelters. Thus, refuge sharing did not lead to increased frequencies of social associations while lizards were active, and we did not find any evidence that refuge sharing was a precursor to sleepy lizard social behaviour. Our study of an unusually social reptile provides both quantitative data on the relationship between refuge sharing and social associations during periods of activity and further insights into the evolution of social behaviour in vertebrates

Centerscope

Centerscope, formerly Scope, was published by the Boston University Medical Center "to communicate the concern of the Medical Center for the development and maintenance of improved health care in contemporary society.