Filtering and scalability in the ECO distributed event model

Event-based communication is useful in many application domains, ranging from small, centralised applications to large, distributed systems. Many different event models have been developed to address the requirements of different application domains. One such model is the ECO model which was designed to support distributed virtual world applications. Like many other event models, ECO has event filtering capabilities meant to improve scalability by decreasing network traffic in a distributed implementation. Our recent work in event-based systems has included building a fully distributed version of the ECO model, including event filtering capabilities. This paper describes the results of our evaluation of filters as a means of achieving increased scalability in the ECO model. The evaluation is empirical and real data gathered from an actual event-based system is used

Design of a reusable kinetic energy absorber for an astronaut safety tether to be used during extravehicular activities on the Space Station

The goal of this project is to design a reusable safety device for a waist tether which will absorb the kinetic energy of an astronaut drifting away from the Space Station. The safety device must limit the tension of the tether line in order to prevent damage to the astronaut's space suit or to the structure of the spacecraft. The tether currently used on shuttle missions must be replaced after the safety feature has been developed. A reusable tether for the Space Station would eliminate the need for replacement tethers, conserving space and mass. This report presents background information, scope and limitations, methods of research and development, alternative designs, a final design solution and its evaluation, and recommendations for further work

Retrograde Accretion and Merging Supermassive Black Holes

We investigate whether a circumbinary gas disc can coalesce a supermassive black hole binary system in the centre of a galaxy. This is known to be problematic for a prograde disc. We show that in contrast, interaction with a retrograde circumbinary disc is considerably more effective in shrinking the binary because there are no orbital resonances. The binary directly absorbs negative angular momentum from the circumbinary disc by capturing gas into a disc around the secondary black hole, or discs around both holes if the binary mass ratio is close to unity. In many cases the binary orbit becomes eccentric, shortening the pericentre distance as the eccentricity grows. In all cases the binary coalesces once it has absorbed the angular momentum of a gas mass comparable to that of the secondary black hole. Importantly, this conclusion is unaffected even if the gas inflow rate through the disc is formally super--Eddington for either hole. The coalescence timescale is therefore always $\sim M_2/\dot M$, where $M_2$ is the secondary black hole mass and $\dot M$ the inflow rate through the circumbinary disc.Comment: 8 pages, 4 figures. Accepted for publication in MNRAS. Movies of the simulations can be found at: http://www.astro.le.ac.uk/users/cjn12/RetroBinaryMovies.htm

Plasmon Evolution and Charge-Density Wave Suppression in Potassium Intercalated Tantalum Diselenide

We have investigated the influence of potassium intercalation on the formation of the charge-density wave (CDW) instability in 2H-tantalum diselenide by means of Electron Energy-Loss Spectroscopy and density functional theory. Our observations are consistent with a filling of the conduction band as indicated by a substantial decrease of the plasma frequency in experiment and theory. In addition, elastic scattering clearly points to a destruction of the CDW upon intercalation as can be seen by a vanishing of the corresponding superstructures. This is accompanied by a new superstructure, which can be attributed to the intercalated potassium. Based on the behavior of the c-axis upon intercalation we argue in favor of interlayer-sites for the alkali-metal and that the lattice remains in the 2H-modification

Human endogenous retrovirus K106 (HERV-K106) was infectious after the emergence of anatomically modern humans.

HERV-K113 and HERV-K115 have been considered to be among the youngest HERVs because they are the only known full-length proviruses that are insertionally polymorphic and maintain the open reading frames of their coding genes. However, recent data suggest that HERV-K113 is at least 800,000 years old, and HERV-K115 even older. A systematic study of HERV-K HML2 members to identify HERVs that may have infected the human genome in the more recent evolutionary past is lacking. Therefore, we sought to determine how recently HERVs were exogenous and infectious by examining sequence variation in the long terminal repeat (LTR) regions of all full-length HERV-K loci. We used the traditional method of inter-LTR comparison to analyze all full length HERV-Ks and determined that two insertions, HERV-K106 and HERV-K116 have no differences between their 5' and 3' LTR sequences, suggesting that these insertions were endogenized in the recent evolutionary past. Among these insertions with no sequence differences between their LTR regions, HERV-K106 had the most intact viral sequence structure. Coalescent analysis of HERV-K106 3' LTR sequences representing 51 ethnically diverse individuals suggests that HERV-K106 integrated into the human germ line approximately 150,000 years ago, after the emergence of anatomically modern humans

Pressure ulcer related pain in community populations: a prevalence survey.

BACKGROUND: Pressure ulcers are costly to the healthcare provider and can have a major impact on patient's quality of life. One of the most distressing symptoms reported is pain. There is very little published data on the prevalence and details of pain experienced by patients with pressure ulcers, particularly in community populations. The study was conducted in two community NHS sites in the North of England. METHODS: The aim was to estimate the prevalence of pressure area related pain within a community population. We also explored the type and severity of the pain and its association with pressure ulcer classification. A cross-sectional survey was performed of community nurses caseloads to identify adult patients with pressure ulcers and associated pain. Consenting patients then had a full pain assessment and verification of pressure ulcer grade. RESULTS: A total of 287 patients were identified with pressure ulcers (0.51 per 1000 adult population). Of the 176 patients who were asked, 133 (75.6%) reported pain. 37 patients consented to a detailed pain assessment. Painful pressure ulcers of all grades and on nearly all body sites were identified. Pain intensity was not related to number or severity of pressure ulcer. Both inflammatory and neuropathic pain were reported at all body sites however the proportion of neuropathic pain was greater in pressure ulcers on lower limbs. CONCLUSIONS: This study has identified the extent and type of pain suffered by community patients with pressure ulcers and indicates the need for systematic and regular pain assessment and treatment

Digital Parallel Processor Array for Optimum Path Planning

The invention computes the optimum path across a terrain or topology represented by an array of parallel processor cells interconnected between neighboring cells by links extending along different directions to the neighboring cells. Such an array is preferably implemented as a high-speed integrated circuit. The computation of the optimum path is accomplished by, in each cell, receiving stimulus signals from neighboring cells along corresponding directions, determining and storing the identity of a direction along which the first stimulus signal is received, broadcasting a subsequent stimulus signal to the neighboring cells after a predetermined delay time, whereby stimulus signals propagate throughout the array from a starting one of the cells. After propagation of the stimulus signal throughout the array, a master processor traces back from a selected destination cell to the starting cell along an optimum path of the cells in accordance with the identity of the directions stored in each of the cells

EVOLUTION OF THE STRATOSPHERIC TEMPERATURE AND CHEMICAL COMPOSITION OVER ONE TITANIAN YEAR

Since the Voyager 1 (V1) flyby in 1980, Titans exploration from space and the ground has been ongoing for more than a full revolution of Saturn around the Sun (one Titan year or 29.5 Earth years was completed in May 2010). In this study we search for temporal variations affecting Titans atmospheric thermal and chemical structure within that year. We process Cassini CIRS data taken during the Titan flybys from 2006-2013 and compare them to the 1980 V1IRIS spectra (re-analyzed here). We also consider data from Earth-based and -orbiting observatories (such as from the ISO, re-visited). When we compare the CIRS 2010 and the IRIS data we find limited inter-annual variations, below the 25 or35 levels for the lower and middle, or the high latitudes, respectively. A return to the 1980 stratospheric temperatures and abundances is generally achieved from 50degN to 50degS, indicative of the solar radiation being the dominating energy source at 10 AU, as for the Earth, as predicted by GCM and photochemical models. However, some exceptions exist among the most complex hydrocarbons (C4H2 and C3H4), especially in the North. In the Southern latitudes, since 2012, we see a trend for an increase of several trace gases, possibly indicative of a seasonal atmospheric reversal. At the Northern latitudes we found enhanced abundances around the period of the northern spring equinox in mid-2009 (as in Bampasidis et al. 2012), which subsequently decreased (from 2010-2012) returning to values similar to those found in the V1 epoch a Titanian year before