7,938 research outputs found
Monotone Iteration And Green’s Functions For Boundary Value Problems
An iteration scheme is given for approximating solutions of boundary problems of the form Ly = f(x, y), Ty(x) = r, where L is an nth order linear differential operator, f is continuous, and T is a continuous linear operator from Cn-l(I) into Rn. The scheme is based on the condition that the Green\u27s function G(x, s) for the associated linear problem Ly = 0, Ty = 0 exists and has sign independent of s. © 1981 American Mathematical Society
Insect and allied pests of extensive farming
Produced in conjunction with the Plant Protection Society of WA. The Society is an organisation of farmers, scientists, commercial representatives and others interested in all aspects of plant protection. It provides essential liaison between farmers, industry & Government. It aims to inform members, Government, Industry and the public on: plant pest management and control, including weeds, insects, diseases and vertebrate and invertebrate pests, stored plant products protection, the importance of plant protection, pesticides and the environment, safe handling of pesticides; and pesticide application methods and technology.https://researchlibrary.agric.wa.gov.au/bulletins/1240/thumbnail.jp
A Concept for Attribute-Based Authorization on D-Grid Resources
In Germany's D-Grid project numerous Grid communities are working together to provide a common overarching Grid infrastructure. The major aims of D-Grid are the integration of existing Grid deployments and their interoperability. The challenge lies in the heterogeneity of the current implementations: three Grid middleware stacks and different Virtual Organization management approaches have to be embraced to achieve the intended goals. In this article we focus oil the implementation of an attribute-based authorization infrastructure that not only leverages the well-known VO attributes but also campus attributes managed by a Shibboleth federation
Gravitational Instantons and Fluxes from M/F-theory on Calabi-Yau fourfolds
We compactify four-dimensional N=1 gauged supergravity theories on a circle
including fluxes for shift-symmetric scalars. Four-dimensional Taub-NUT
gravitational instantons universally correct the three-dimensional
superpotential in the absence of fluxes. In the presence of fluxes these
Taub-NUT instanton contributions are no longer gauge-invariant. Invariance can
be restored by gauge instantons on top of Taub-NUT instantons. We establish the
embedding of this scenario into M-theory. Circle fluxes and gaugings arise from
a restricted class of M-theory four-form fluxes on a resolved Calabi-Yau
fourfold. The M5-brane on the base of the elliptic fourfold dualizes into the
universal Taub-NUT instanton. In the presence of fluxes this M5-brane is
anomalous. We argue that anomaly free contributions arise from involved
M5-brane geometries dual to gauge-instantons on top of Taub-NUT instantons.
Adding a four-dimensional superpotential to the gravitational instanton
corrections leads to three-dimensional Anti-de Sitter vacua at stabilized
compactification radius. We comment on the possibility to uplift these M-theory
vacua, and to tunnel to four-dimensional F-theory vacua.Comment: 47 pages, 2 figure
The X-ray binary population in M33: II. X-ray spectra and variability
In this paper we investigate the X-ray spectra and X-ray spectral variability
of compact X-ray sources for 3 Chandra observations of the Local Group galaxy
M33. The observations are centered on the nucleus and the star forming region
NGC 604. In the observations 261 sources have been detected. For a total of 43
sources the number of net counts is above 100, sufficient for a more detailed
spectral fitting. Of these sources, 25 have been observed in more than one
observation, allowing the study of spectral variability on ~months timescales.
A quarter of the sources are found to be variable between observations.
However, except for two foreground sources, no source is variable within any
observation above the 99% confidence level. Only six sources show significant
spectral variability between observations. A comparison of N_H values with HI
observations shows that X-ray absorption values are consistent with Galactic
X-ray binaries and most sources in M33 are intrinsically absorbed. The pattern
of variability and the spectral parameters of these sources are consistent with
the M33 X-ray source population being dominated by X-ray binaries: Two thirds
of the 43 bright sources have spectral and timing properties consistent with
X-ray binaries; we also find two candidates for super-soft sources and two
candidates for quasi-soft sources.Comment: 25 pages, ApJ accepte
Trapping and observing single atoms in the dark
A single atom strongly coupled to a cavity mode is stored by
three-dimensional confinement in blue-detuned cavity modes of different
longitudinal and transverse order. The vanishing light intensity at the trap
center reduces the light shift of all atomic energy levels. This is exploited
to detect a single atom by means of a dispersive measurement with 95%
confidence in 0.010 ms, limited by the photon-detection efficiency. As the atom
switches resonant cavity transmission into cavity reflection, the atom can be
detected while scattering about one photon
Coherent transport of neutral atoms in spin-dependent optical lattice potentials
We demonstrate the controlled coherent transport and splitting of atomic wave
packets in spin-dependent optical lattice potentials. Such experiments open
intriguing possibilities for quantum state engineering of many body states.
After first preparing localized atomic wave functions in an optical lattice
through a Mott insulating phase, we place each atom in a superposition of two
internal spin states. Then state selective optical potentials are used to split
the wave function of a single atom and transport the corresponding wave packets
in two opposite directions. Coherence between the wave packets of an atom
delocalized over up to 7 lattice sites is demonstrated.Comment: 4 pages, 6 figure
Cone opsins and response of female chamois ( Rupicapra rupicapra ) to differently coloured raincoats
Alpine species are often exposed to intense levels of human recreational activities. Exactly how human disturbances influence the behaviour of these species is still open to much debate. For example, little is known regarding how the colourful clothing often worn by tourists influences the behaviour of animals. Tourists wearing colourful clothing may be more conspicuous to local wildlife and thus cause more disturbances. We therefore investigated this question in female chamois (Rupicapra rupicapra) in the Swiss Alps. We firstly investigated, via a morphological and an immunohistochemical approach, whether chamois are likely to have colour vision and would therefore be more likely to respond to different coloured clothing. We detected evidence of two cone types—short-wavelength-sensitive cones (S-cones, JH 455) and middle-wavelength-sensitive cones (M-cones, JH492) in the chamois retina—suggesting that chamois have dichromatic vision, similar to other ungulates. Secondly, via behavioural assays where a person wearing one of three coloured coats commonly worn by tourists (red, yellow and blue) approached a female chamois, we show that neither the alert and flight initiation distance nor the site of refuge were influenced by the raincoat colour. In addition, behavioural responses of the chamois were neither influenced by animal group size nor the presence of kids nor the time of the experiment. The results suggest that, although chamois possess colour vision, they do not react more strongly towards conspicuous colours worn by hikers. We discuss our results in light of what is already known about chamois biology and suggest implications for future studie
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