Description of the Mast Flight System

The Mast Flight System is composed of several subsystems. Primary among these is the Deployable Mast Subsystem (DMS) which consists of a beam assembly and an associated mechanism for deploying and retracting the beam. The beam assembly is a joint dominated graphite epoxy and titanium truss as is expected of future large space structures. Integral to the beam assembly are actuators, sensors and associated electronics which are available for excitation and damping as desired by the experimenter. The beam structural characteristics can also be modified as desired by the experimenter using the Parameter Modification Device installed at the end of the beam. Data measured on the beam by the sensors and commands to the actuators are transmitted along the beam digitally at 150 Hz using a standard 1553 type bus. The Modular Distributed Information Sybsystem (MDIS) computer functions as bus master and ensures that all experimental data is saved for future analysis. The MDIS computer also performs a safing function to prevent inadvertent overexcitation of the beam. Finally, the Excitation and Damping Subsystem (EDS) computer is available to the experimenter for implementation of control algorithms or any other numerical operations as desired. Data from all system sensors can be accessed by the EDS computer

Investigation of quantitative measures related to reading disability in a large sample of sib-pairs from the UK

We describe a family-based sample of individuals with reading disability collected as part of a quantitative trait loci (QTL) mapping study. Eighty-nine nuclear families (135 independent sib-pairs) were identified through a single proband using a traditional discrepancy score of predicted/actual reading ability and a known family history. Eight correlated psychometric measures were administered to each sibling, including single word reading, spelling, similarities, matrices, spoonerisms, nonword and irregular word reading, and a pseudohomophone test. Summary statistics for each measure showed a reduced mean for the probands compared to the co-sibs, which in turn was lower than that of the population. This partial co-sib regression back to the mean indicates that the measures are influenced by familial factors and therefore, may be suitable for a mapping study. The variance of each of the measures remained largely unaffected, which is reassuring for the application of a QTL approach. Multivariate genetic analysis carried out to explore the relationship between the measures identified a common factor between the reading measures that accounted for 54% of the variance. Finally the familiality estimates (range 0.32–0.73) obtained for the reading measures including the common factor (0.68) supported their heritability. These findings demonstrate the viability of this sample for QTL mapping, and will assist in the interpretation of any subsequent linkage findings in an ongoing genome scan

Rewriting Semantics of Meta-Objects and Composable Distributed Services1 1Supported by DARPA through Rome Laboratories Contract F30602-97-C-0312, by DARPA and NASA through Contract NAS2-98073, by Office of Naval Research Contract N00014-99-C-0198, and by National Science Foundation Grants CCR-9505960 and CCR-9633363, and CCR-9900334.

AbstractCommunication between distributed objects may have to be protected against random failures and malicious attacks; also, communication timeliness may be essential or highly desired. Therefore, a distributed application often has to be extended with communication services providing some kind of fault-tolerance, secrecy, or quality-of-service guarantees. Ideally, such services should be defined in a highly modular and dynamically composable way, so that the combined assurance of several services can be achieved by composition in certain cases, and so that services can be added or removed from applications at runtime in response to changes in the environment. To reason about the formal properties of such composable communication services one first needs to give them a precise semantics. This paper proposes a rewriting logic semantics for the so-called “onion skin” model of distributed object reflection, in which different meta-objects, providing different communication services, can be stacked on top of a basic application object. Since the correct behavior of a service depends on the type of hostile environment, against which the service must protect the application, rewriting logic should also be used to specify such hostile environments. The service guarantees are then guarantees about the behavior specified by the union of the rewrite theories specifying the basic application, the services, and the hostile environment

Effect of nanoencapsulation using PLGA on antioxidant and antimicrobial activities of guabiroba fruit phenolic extract.

Guabiroba fruit has been highlighted for its high phytochemical content, particularly of phenolic compounds. The stability, bioavailability, and bioactivity of these compounds can be enhanced by nanoencapsulation, to improve functionality. Poly (D,L-lactic-co-glycolic) acid (PLGA) nanoparticles containing phenolic extract of guabiroba (GPE) were synthesized by an adapted emulsion-evaporation method and their physico-chemical and functional properties were studied at two lactic to glycolic acid ratios (50:50 and 65:35). Higher (P < 0.05) or equivalent antioxidant capacity compared to free GPE were observed for GPE-loaded nanoparticles. Free extract and PLGA nanoparticles were effective inhibitors of Listeria innocua, with lower (P < 0.05) GPE concentrations required for inhibition when nanoencapsulated. Also, reduction of ROS generation in non-cancer cells was achieved with lower GPE concentrations (P < 0.05) after encapsulation. These results suggest that PLGA nanoparticles can be used as a delivery system for phenolic compounds at lower levels than originally required for enhanced functional properties

A Component-oriented Framework for Autonomous Agents

The design of a complex system warrants a compositional methodology, i.e., composing simple components to obtain a larger system that exhibits their collective behavior in a meaningful way. We propose an automaton-based paradigm for compositional design of such systems where an action is accompanied by one or more preferences. At run-time, these preferences provide a natural fallback mechanism for the component, while at design-time they can be used to reason about the behavior of the component in an uncertain physical world. Using structures that tell us how to compose preferences and actions, we can compose formal representations of individual components or agents to obtain a representation of the composed system. We extend Linear Temporal Logic with two unary connectives that reflect the compositional structure of the actions, and show how it can be used to diagnose undesired behavior by tracing the falsification of a specification back to one or more culpable components

Moderate relationships between NAA and cognitive ability in healthy adults:implications for cognitive spectroscopy

Background: Proton Magnetic Resonance Spectroscopy (H-MRS) is a non-invasive imaging technique that enables quantification of neurochemistry in vivo and thereby facilitates investigation of the biochemical underpinnings of human cognitive variability. Studies in the field of cognitive spectroscopy have commonly focused on relationships between measures of N-acetyl aspartate (NAA), a surrogate marker of neuronal health and function, and broad measures of cognitive performance, such as IQ. Methodology/Principal Findings: In this study, we used H-MRS to interrogate single-voxels in occipitoparietal and frontal cortex, in parallel with assessments of psychometric intelligence, in a sample of 40 healthy adult participants. We found correlations between NAA and IQ that were within the range reported in previous studies. However, the magnitude of these effects was significantly modulated by the stringency of data screening and the extent to which outlying values contributed to statistical analyses. Conclusions/Significance: H-MRS offers a sensitive tool for assessing neurochemistry non-invasively, yet the relationships between brain metabolites and broad aspects of human behavior such as IQ are subtle. We highlight the need to develop an increasingly rigorous analytical and interpretive framework for collecting and reporting data obtained from cognitive spectroscopy studies of this kind

On security analysis of periodic systems: expressiveness and complexity

Development of automated technological systems has seen the increase in interconnectivity among its components. This includes Internet of Things (IoT) and Industry 4.0 (I4.0) and the underlying communication between sensors and controllers. This paper is a step toward a formal framework for specifying such systems and analyzing underlying properties including safety and security. We introduce automata systems (AS) motivated by I4.0 applications. We identify various subclasses of AS that reflect different types of requirements on I4.0. We investigate the complexity of the problem of functional correctness of these systems as well as their vulnerability to attacks. We model the presence of various levels of threats to the system by proposing a range of intruder models, based on the number of actions intruders can use