11,028 research outputs found
A homomorphism theorem and a Trotter product formula for quantum stochastic flows with unbounded coefficients
We give a new method for proving the homomorphic property of a quantum
stochastic ow satisfying a quantum stochastic differential equation with
unbounded coefficients, under some further hypotheses. As an application, we
prove a Trotter product formula for quantum stochastic ows and obtain quantum
stochastic dilations of a class of quantum dynamical semigroups generalizing
results of [5
Better communication research project : language and literacy attainment of pupils during early years and through KS2 : does teacher assessment at five provide a valid measure of children's current and future educational attainments?
It is well-established that language skills are amongst the best predictors of educational success. Consistent with this, findings from a population-based longitudinal study of parents and children in the UK indicate that language development at the age of two years predicts childrenâs performance on entering primary school. Moreover, children who enter school with poorly developed speech and language are at risk of literacy difficulties and educational
underachievement is common in such children. Whatever the origin of childrenâs problems with language and communication, the poor educational attainment of children with language learning difficulties is an important concern for educational polic
Criminal law as a security project
This paper asks how criminal might be understood as a security project. Following Valverdeâs lead, it does this not by trying to define the concept of security, but by looking at the operation of the temporal and spatial logics of the criminal law. It looks first at the basic logics of time and space in conceptions of criminal liability and jurisdiction, before reviewing some recent developments which challenge these practices and what these might mean for criminal law as a security project
Enantioselective Synthesis of Tryptophan Derivatives by a Tandem FriedelâCrafts Conjugate Addition/Asymmetric Protonation Reaction
The tandem FriedelâCrafts conjugate addition/asymmetric protonation reaction between 2-substituted indoles and methyl 2-acetamidoacrylate is reported. The reaction is catalyzed by (R)-3,3âČ-dibromo-BINOL in the presence of stoichiometric SnCl_4, and is the first example of a tandem conjugate addition/asymmetric protonation reaction using a BINOL·SnCl_4 complex as the catalyst. A range of indoles furnished synthetic tryptophan derivatives in good yields and high levels of enantioselectivity, even on a preparative scale. The convergent nature of this transformation should lend itself to the preparation of unnatural tryptophan derivatives for use in a broad array of synthetic and biological applications
Physiological Ecology of Four Endemic Alabama Species and the Exotic Asiatic Weatherfish, \u3ci\u3eMisgurnus anguillicaudatus\u3c/i\u3e (Cantor, 1842)
The occurrence of Asiatic Weatherfish, Misgurnus anguillicaudatus, in Alabama, a state known for its rich biodiversity, has generated concern among conservation managers. The current study used respirometry techniques to investigate the effects of increasing temperature on four native southeastern fishes (one cyprinid, two percids, and one elassomid) and the non-native M. anguillicaudatus. A minimum of five individuals of each species were used, and three experimental temperatures were chosen to represent spring and summer averages of northeast Alabama streams (15, 20, and 25°C). Overall, mean standard metabolic rates (SMRs) for M. anguillicaudatus were low (97.01, 127.75, and 158.50 mg O2 kg-1h-1 at 15, 20, and 25°C, respectively); M. anguillicaudatus was the only species for which SMR did not significantly increase with temperature (p = 0.467). In contrast, mean SMRs for all native species examined were higher than M. anguillicaudatus rates at a given temperature, and mean SMRs for Cyprinella caerulea, Etheostoma brevirostrum, and Etheostoma ditrema exhibited significant increases in SMR when temperatures were increased (e.g. 403.46, 704.42, and 1150.03 mg O2 kg-1h-1 at 25°C, respectively) (p \u3c 0.01). Elassoma zonatum displayed highly significant increases in SMR when temperature increased from 15-20°C (p \u3c 0.001). Overall, the abiotic tolerances of M. anguillicaudatus may facilitate further establishment that could lead to negative impacts on native species
Evacuation planning in the Auckland Volcanic Field, New Zealand: a spatio-temporal approach for emergency management and transportation network decisions
Auckland is the largest city in New Zealand (pop. 1.5 million) and is situated atop an active monogenetic volcanic
field. When volcanic activity next occurs, the most effective means of protecting the people who reside and work
in the region will be to evacuate the danger zone prior to the eruption. This study investigates the evacuation
demand throughout the Auckland Volcanic Field and the capacity of the transportation network to fulfil such a
demand. Diurnal movements of the population are assessed and, due to the seemingly random pattern of
eruptions in the past, a non-specific approach is adopted to determine spatial vulnerabilities at a micro-scale (neighbourhoods).
We achieve this through the calculation of population-, household- and car-to-exit capacity ratios. Following
an analysis of transportation hub functionality and the susceptibility of motorway bridges to a new eruption,
modelling using dynamic route and traffic assignment was undertaken to determine various evacuation attributes
at a macro-scale and forecast total network clearance times. Evacuation demand was found to be highly correlated
to diurnal population movements and neighbourhood boundary types, a trend that was also evident in the evacuation
capacity ratio results. Elevated population to evacuation capacity ratios occur during the day in and around
the central city, and at night in many of the outlying suburbs. Low-mobility populations generally have better than
average access to public transportation. Macro-scale vulnerability was far more contingent upon the destination of
evacuees, with favourable results for evacuation within the region as opposed to outside the region. Clearance
times for intra-regional evacuation ranged from one to nine hours, whereas those for inter-regional evacuation were
found to be so high, that the results were unrealistic. Therefore, we conclude that, from a mobility standpoint, there
is considerable merit to intra-regional evacuation
Mantle heterogeneity controls on small-volume basaltic volcanism: Reply
ArtĂculo de publicaciĂłn ISIEruptions of basaltic material in small-scale volcanic fields located in intraplate settings display a very diverse range in physical and chemical characteristics. Despite its relevance to the understanding of volcanic hazards, the relationship between physical properties of eruptions (explosivity, volume, location) and chemical composition of erupted products has, to date, not been investigated. Here we present a relationship between mantle heterogeneity and extents of partial melting, and both erupted volumes and eruptive style from the Auckland Volcanic Field (New Zealand), and we suggest that this provides a general model for small-scale "monogenetic" magmatic systems globally. Small volcanic centers consistently take the form of nephelinitic tuff rings and scoria cones, whereas larger centers are produced from effusive eruptions of less alkalic magmas. Nephelinitic melts are generated by melting of a deep, carbonated source, whereas less alkalic melts are the products of melting of a shallower, noncarbonated source. U-Th-Ra isotope data from eruptions closely paired in space and time show that mixing between magmas is extremely limited as a consequence of different ascent mechanisms due to differential segregation of melts from varying sources (early, carbonated melts ascending by higher porosity channels, and later, uncarbonated melts by a more diffusive regime). This suggests that extraction of melt is nearly instantaneous in these environments. Our results stress the importance of melting and magma dynamics in determining the size and style of eruptions in small volcanic fields, and suggest that mantle controls should be an important consideration in volcanic hazard assessment.Centro de Excelencia en Geotermia de los Andes (CEGA, Chile) by FONDAP (Fondo de Financiamiento de Centros de Investigacion en Areas Prioritarias)
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