Reliable dual-redundant sensor failure detection and identification for the NASA F-8 DFBW aircraft

A technique was developed which provides reliable failure detection and identification (FDI) for a dual redundant subset of the flight control sensors onboard the NASA F-8 digital fly by wire (DFBW) aircraft. The technique was successfully applied to simulated sensor failures on the real time F-8 digital simulator and to sensor failures injected on telemetry data from a test flight of the F-8 DFBW aircraft. For failure identification the technique utilized the analytic redundancy which exists as functional and kinematic relationships among the various quantities being measured by the different control sensor types. The technique can be used not only in a dual redundant sensor system, but also in a more highly redundant system after FDI by conventional voting techniques reduced to two the number of unfailed sensors of a particular type. In addition the technique can be easily extended to the case in which only one sensor of a particular type is available

Repeating Spatial-Temporal Motifs of CA3 Activity Dependent on Engineered Inputs from Dentate Gyrus Neurons in Live Hippocampal Networks.

Anatomical and behavioral studies, and in vivo and slice electrophysiology of the hippocampus suggest specific functions of the dentate gyrus (DG) and the CA3 subregions, but the underlying activity dynamics and repeatability of information processing remains poorly understood. To approach this problem, we engineered separate living networks of the DG and CA3 neurons that develop connections through 51 tunnels for axonal communication. Growing these networks on top of an electrode array enabled us to determine whether the subregion dynamics were separable and repeatable. We found spontaneous development of polarized propagation of 80% of the activity in the native direction from DG to CA3 and different spike and burst dynamics for these subregions. Spatial-temporal differences emerged when the relationships of target CA3 activity were categorized with to the number and timing of inputs from the apposing network. Compared to times of CA3 activity when there was no recorded tunnel input, DG input led to CA3 activity bursts that were 7× more frequent, increased in amplitude and extended in temporal envelope. Logistic regression indicated that a high number of tunnel inputs predict CA3 activity with 90% sensitivity and 70% specificity. Compared to no tunnel input, patterns of >80% tunnel inputs from DG specified different patterns of first-to-fire neurons in the CA3 target well. Clustering dendrograms revealed repeating motifs of three or more patterns at up to 17 sites in CA3 that were importantly associated with specific spatial-temporal patterns of tunnel activity. The number of these motifs recorded in 3 min was significantly higher than shuffled spike activity and not seen above chance in control networks in which CA3 was apposed to CA3 or DG to DG. Together, these results demonstrate spontaneous input-dependent repeatable coding of distributed activity in CA3 networks driven by engineered inputs from DG networks. These functional configurations at measured times of activation (motifs) emerge from anatomically accurate feed-forward connections from DG through tunnels to CA3

Traumatic dissection and rupture of the abdominal aorta as a complication of the Heimlich maneuver

Although the Heimlich maneuver is considered the best intervention for relieving acute upper airway obstruction, several complications have been reported in the literature. These complications can occur as a result of an increase in abdominal pressure leading to a variety of well-documented visceral injuries, including the great vessels. Acute abdominal aortic thrombosis after the Heimlich maneuver is a rare but recognized event; however, to date no case of traumatic dissection and rupture of the abdominal aorta has been described. We report the first known case, to our knowledge, of a traumatic dissection and rupture of the abdominal aorta after a forcefully applied Heimlich maneuver

Stellar Mass to Halo Mass Scaling Relation for X-ray Selected Low Mass Galaxy Clusters and Groups out to Redshift z≈1z\approx1

We present the stellar mass-halo mass scaling relation for 46 X-ray selected low-mass clusters or groups detected in the XMM-BCS survey with masses $2\times10^{13}M_{\odot}\lesssim M_{500}\lesssim2.5\times10^{14}M_{\odot}$ at redshift $0.1\le z \le1.02$. The cluster binding masses $M_{500}$ are inferred from the measured X-ray luminosities \Lx, while the stellar masses $M_{\star}$ of the galaxy populations are estimated using near-infrared imaging from the SSDF survey and optical imaging from the BCS survey. With the measured \Lx\ and stellar mass $M_{\star}$, we determine the best fit stellar mass-halo mass relation, accounting for selection effects, measurement uncertainties and the intrinsic scatter in the scaling relation. The resulting mass trend is $M_{\star}\propto M_{500}^{0.69\pm0.15}$, the intrinsic (log-normal) scatter is $\sigma_{\ln M_{\star}|M_{500}}=0.36^{+0.07}_{-0.06}$, and there is no significant redshift trend $M_{\star}\propto (1+z)^{-0.04\pm0.47}$, although the uncertainties are still large. We also examine $M_{\star}$ within a fixed projected radius of $0.5$~Mpc, showing that it provides a cluster binding mass proxy with intrinsic scatter of $\approx93\%$ (1$\sigma$ in $M_{500}$). We compare our $M_{\star}=M_{\star}(M_{500}, z)$ scaling relation from the XMM-BCS clusters with samples of massive, SZE-selected clusters ($M_{500}\approx6\times10^{14}M_{\odot}$) and low mass NIR-selected clusters ($M_{500}\approx10^{14}M_{\odot}$) at redshift $0.6\lesssim z \lesssim1.3$. After correcting for the known mass measurement systematics in the compared samples, we find that the scaling relation is in good agreement with the high redshift samples, suggesting that for both groups and clusters the stellar content of the galaxy populations within $R_{500}$ depends strongly on mass but only weakly on redshift out to $z\approx1$.Comment: 15 pages, 10 figures. Accepted for publication in MNRA

The role of interplanetary scattering in western hemisphere large solar energetic particle events

Using high-sensitivity instruments on the ACE spacecraft, we have examined the intensities of O and Fe in 14 large solar energetic particle events whose parent activity was in the solar western hemisphere. Sampling the intensities at low (~273 keV nucleon to the -1) and high (~12 MeV nucleon to the -1) energies, we find that at the same kinetic energy per nucleon, the Fe/O ratio decreases with time, as has been reported previously. This behavior is seen in more than 70% of the cases during the rise to maximum intensity and continues in most cases into the decay phase. We find that for most events if we compare the Fe intensity with the O intensity at a higher kinetic energy per nucleon, the two time-intensity profiles are strikingly similar. Examining alternate scenarios that could produce this behavior, we conclude that for events showing this behavior the most likely explanation is that the Fe and O share similar injection profiles near the Sun, and that scattering in the interplanetary medium dominates the profiles observed at 1 AU

Complex networks generated by the Penna bit-string model: emergence of small-world and assortative mixing

The Penna bit-string model successfully encompasses many phenomena of population evolution, including inheritance, mutation, evolution, and aging. If we consider social interactions among individuals in the Penna model, the population will form a complex network. In this paper, we first modify the Verhulst factor to control only the birth rate, and introduce activity-based preferential reproduction of offspring in the Penna model. The social interactions among individuals are generated by both inheritance and activity-based preferential increase. Then we study the properties of the complex network generated by the modified Penna model. We find that the resulting complex network has a small-world effect and the assortative mixing property

Genetic Mechanisms Underlying the Pathogenicity of Cold-Stressed Salmonella Enterica Serovar Typhimurium in Cultured Intestinal Epithelial Cells

Salmonella encounters various stresses in the environment and in the host during infection. The effects of cold (5 C, 48 h), peroxide (5 mM H2O2, 5 h) and acid stress (pH 4.0, 90 min) were tested on pathogenicity of Salmonella. Prior exposure of Salmonella to cold stress significantly (P \u3c 0.05) increased adhesion and invasion of cultured intestinal epithelial (Caco-2) cells. This increased Salmonella-host cell association was also correlated with significant induction of several virulence-associated genes, implying an increased potential of cold-stressed Salmonella to cause an infection. In Caco-2 cells infected with cold-stressed Salmonella, genes involved in the electron transfer chain were significantly induced, but no simultaneous significant increase in expression of antioxidant genes that neutralize the effect of superoxide radicals or reactive oxygen species was observed. Increased production of caspase 9 and caspase 3/7 was confirmed during host cell infection with cold-stressed Salmonella. Further, a prophage gene, STM2699, induced in cold-stressed Salmonella and a spectrin gene, SPTAN1, induced in Salmonella-infected intestinal epithelial cells were found to have a significant contribution in increased adhesion and invasion of cold-stressed Salmonella in epithelial cells

Spitzer IRAC Low Surface Brightness Observations of the Virgo Cluster

We present 3.6 and 4.5 micron Spitzer IRAC imaging over 0.77 square degrees at the Virgo cluster core for the purpose of understanding the formation mechanisms of the low surface brightness intracluster light features. Instrumental and astrophysical backgrounds that are hundreds of times higher than the signal were carefully characterized and removed. We examine both intracluster light plumes as well as the outer halo of the giant elliptical M87. For two intracluster light plumes, we use optical colors to constrain their ages to be greater than 3 & 5 Gyr, respectively. Upper limits on the IRAC fluxes constrain the upper limits to the masses, and optical detections constrain the lower limits to the masses. In this first measurement of mass of intracluster light plumes we find masses in the range of 5.5 x 10^8 - 4.5 x 10^9 and 2.1 x 10^8 - 1.5 x 10^9 solar masses for the two plumes for which we have coverage. Given their expected short lifetimes, and a constant production rate for these types of streams, integrated over Virgo's lifetime, they can account for the total ICL content of the cluster implying that we do not need to invoke ICL formation mechanisms other than gravitational mechanisms leading to bright plumes. We also examined the outer halo of the giant elliptical M87. The color profile from the inner to outer halo of M87 (160 Kpc) is consistent with either a flat or optically blue gradient, where a blue gradient could be due to younger or lower metallicity stars at larger radii. The similarity of the age predicted by both the infrared and optical colors (> few Gyr) indicates that the optical measurements are not strongly affected by dust extinction.Comment: 16 pages including appendix, 9 figures, ApJ accepte

Seed populations for large solar particle events of cycle 23

Using high-resolution mass spectrometers on board the Advanced Composition Explorer (ACE), we surveyed the event-averaged ~0.1-60 MeV/nuc heavy ion elemental composition in 64 large solar energetic particle (LSEP) events of cycle 23. Our results show the following: (1) The rare isotope ^3He is greatly enhanced over the corona or the solar wind values in 46% of the events. (2) The Fe/O ratio decreases with increasing energy up to ~10 MeV/nuc in ~92% of the events and up to ~60 MeV/nuc in ~64% of the events. (3) Heavy ion abundances from C-Fe exhibit systematic M/g-dependent enhancements that are remarkably similar to those seen in ^3He-rich SEP events and CME-driven interplanetary (IP) shock events. Taken together, these results confirm the role of shocks in energizing particles up to ~60 MeV/nuc in the majority of large SEP events of cycle 23, but also show that the seed population is not dominated by ions originating from the ambient corona or the thermal solar wind, as previously believed. Rather, it appears that the source material for CME-associated large SEP events originates predominantly from a suprathermal population with a heavy ion enrichment pattern that is organized according to the ion's mass-per-charge ratio. These new results indicate that current LSEP models must include the routine production of this dynamic suprathermal seed population as a critical pre-cursor to the CME shock acceleration process