Architectural implications for context adaptive smart spaces

Buildings and spaces are complex entities containing complex social structures and interactions. A smart space is a composite of the users that inhabit it, the IT infrastructure that supports it, and the sensors and appliances that service it. Rather than separating the IT from the buildings and from the appliances that inhabit them and treating them as separate systems, pervasive computing combines them and allows them to interact. We outline a reactive context architecture that supports this vision of integrated smart spaces and explore some implications for building large-scale pervasive systems

Dihydrofolate reductase of Streptococcus faecium II. Purification and some properties of two dihydrofolate reductases from the Amethopterin-resistant mutant, Streptococcus Faecium Var. Durans Strain A

From a single amethopterin-resistant organism, Streptococcus faecium var. durans strain A, two different dihydrofolate reductases have been obtained as essentially homogeneous proteins in good yield. One of the reductases has a similar substrate specificity and turnover number (about 8000 moles per min per mole of enzyme) to the single reductase found in the amethopterin-sensitive strain of S. faecium var. durans, ATCC 8043, and has therefore been designated "wild type." The other enzyme, which is distinguished by its ability to catalyze the reduction of folate, in addition to dihydrofolate, and by its lower turnover number (about 900 with dihydrofolate), has been designated "mutant type." Since the wild type and mutant type reductases have sedimentation constants (s20,buffer) of 2.58 S and 2.04 S, respectively, they are probably significantly different in molecular weight. Each exhibits a single pH optimum at pH 5.8 and is inactivated by urea. Neither is affected by methylmercuric salts but the wild type reductase is inactivated by phenyl-mercuric acetate and p-mercuribenzoate. Monovalent cations increase the activity of the mutant type reductase but decrease that of the wild type reductase. It is suggested that the amethopterin resistance in vivo of strain A depends at least partly on the folate reductase activity of the mutant type reductase

Biological vulnerability to depression: Linked structural and functional brain network findings

Background: Patients in recovery following episodes of major depressive disorder (MDD) remain highly vulnerable to future recurrence. Although psychological determinants of this risk are well established, little is known about associated biological mechanisms. Recent work has implicated the default mode network (DMN) in this vulnerability but specific hypotheses remain untested within the high risk, recovered state of MDD. Aims: To test the hypothesis that there is excessive DMN functional connectivity during task performance within recovered-state MDD and to test for connected DMN cortical gyrification abnormalities. Method: A multimodal structural and functional magnetic resonance imaging (fMRI) study, including task-based functional connectivity and cortical folding analysis, comparing 20 recoveredstate patients with MDD with 20 matched healthy controls. Results: The MDD group showed significant task-based DMN hyperconnectivity, associated with hypogyrification of key DMN regions (bilateral precuneus). Conclusions: This is the first evidence of connected structural and functional DMN abnormalities in recovered-state MDD, supporting recent hypotheses on biological-level vulnerability

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

The global energy balance of Titan

The global energy budget of planets and their moons is a critical factor to influence the climate change on these objects. Here we report the first measurement of the global emitted power of Titan. Long-term (2004–2010) observations conducted by the Composite Infrared Spectrometer (CIRS) onboard Cassini reveal that the total emitted power by Titan is (2.84 ± 0.01) × 10^(14) watts. Together with previous measurements of the global absorbed solar power of Titan, the CIRS measurements indicate that the global energy budget of Titan is in equilibrium within measurement error. The uncertainty in the absorbed solar energy places an upper limit on the energy imbalance of 6.0%

Coherent electronic transport in a multimode quantum channel with Gaussian-type scatterers

Coherent electron transport through a quantum channel in the presence of a general extended scattering potential is investigated using a T-matrix Lippmann-Schwinger approach. The formalism is applied to a quantum wire with Gaussian type scattering potentials, which can be used to model a single impurity, a quantum dot or more complicated structures in the wire. The well known dips in the conductance in the presence of attractive impurities is reproduced. A resonant transmission peak in the conductance is seen as the energy of the incident electron coincides with an energy level in the quantum dot. The conductance through a quantum wire in the presence of an asymmetric potential are also shown. In the case of a narrow potential parallel to the wire we find that two dips appear in the same subband which we ascribe to two quasi bound states originating from the next evanescent mode.Comment: RevTeX with 14 postscript figures include

Going places

Journeys. We all make them. Often they take us to exotic places. Sometimes they take us even further. They might take us through time. Or they might take us into a new way of life. There are times too, when we go all over the world and back again only to find that home is, after all, where it’s all happening. This book contains stories about many different types of journey. We hope you will enjoy travelling into it and finding a world that suits you