Factors affecting the distribution, abundance and diversity of rock-pool fishes on the Cape Peninsula, South Africa

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Detecting a stochastic background of gravitational radiation: Signal processing strategies and sensitivities

We analyze the signal processing required for the optimal detection of a stochastic background of gravitational radiation using laser interferometric detectors. Starting with basic assumptions about the statistical properties of a stochastic gravity-wave background, we derive expressions for the optimal filter function and signal-to-noise ratio for the cross-correlation of the outputs of two gravity-wave detectors. Sensitivity levels required for detection are then calculated. Issues related to: (i) calculating the signal-to-noise ratio for arbitrarily large stochastic backgrounds, (ii) performing the data analysis in the presence of nonstationary detector noise, (iii) combining data from multiple detector pairs to increase the sensitivity of a stochastic background search, (iv) correlating the outputs of 4 or more detectors, and (v) allowing for the possibility of correlated noise in the outputs of two detectors are discussed. We briefly describe a computer simulation which mimics the generation and detection of a simulated stochastic gravity-wave signal in the presence of simulated detector noise. Numerous graphs and tables of numerical data for the five major interferometers (LIGO-WA, LIGO-LA, VIRGO, GEO-600, and TAMA-300) are also given. The treatment given in this paper should be accessible to both theorists involved in data analysis and experimentalists involved in detector design and data acquisition.Comment: 81 pages, 30 postscript figures, REVTE

Dual-energy X-ray absorptiometry scans accurately predict differing body fat content in live sheep

Background There is considerable interest in implementing mobile scanning technology for on-farm body composition analysis on live animals. These experiments evaluated the use of dual energy X-ray absorptiometry (DXA) as an accurate method of total body fat measurement in live sheep. Results In Exp. 1, visceral and whole body fat analysis was undertaken in sheep with body condition scores (BCS) in the range 2 to 3.25 (scale 1: thin to 5: fat). The relationship of BCS was moderately correlated with visceral fat depot mass (r = 0.59, P  0.05, n = 9). There was a moderate correlation between DXA body fat and BCS (r = 0.70, P < 0.01, n = 17), and DXA body fat was highly correlated with chemical body fat (r = 0.81, P < 0.001, n = 9). In Exp. 3, a series of five DXA scans, at 8-week intervals, was performed on growing sheep over a 32-week period. The average BCS ranged from 2.39 ± 0.07 (S.E.M.) to 3.05 ± 0.11 and the DXA body fat (%) ranged from 16.8 ± 0.8 to 24.2 ± 1.2. There was a moderate correlation between DXA body fat and BCS over the 32 weeks (r = 0.61, P < 0.001, n = 24). Conclusions Overall, these experiments indicated that there was good agreement between BCS, DXA and chemical analysis for measuring total body fat in sheep, and that DXA scanning is a valid method for longitudinal measurement of total body fat in live sheep

Leptogenesis, neutrino masses and gauge unification

Leptogenesis is considered in its natural context where Majorana neutrinos fit in a gauge unification scheme and therefore couple to some extra gauge bosons. The masses of some of these gauge bosons are expected to be similar to those of the heavy Majorana particles, and this can have important consequences for leptogenesis. In fact, the effect can go both ways. Stricter bounds are obtained on one hand due to the dilution of the CP-violating effect by new decay and scattering channels, while, in a re-heating scheme, the presence of gauge couplings facilitates the re-population of the Majorana states. The latter effect allows in particular for smaller Dirac couplings.Comment: 11pages, 7 figures. v2: definition of the lepton asymmetry corrected, small numerical changes for the baryon number, conclusion does not change; typos corrected and references adde

Confronting hybrid inflation in supergravity with CMB data

$F$-term GUT inflation coupled to N=1 Supergravity is confronted with CMB data. Corrections to the string mass-per-unit-length away from the Bogomolny limit are taken into account. We find that a superpotential coupling 10^{-7}/\mcN \lesssim \kappa \lesssim 10^{-2}/\mcN, with \mcN the dimension of the Higgs-representation, is still compatible with the data. The parameter space is enlarged in warm inflation, as well as in the curvaton and inhomogeneous reheat scenario. $F$-strings formed at the end of $P$-term inflation are also considered. Because these strings satisfy the Bogomolny bound the bounds are stronger: the gauge coupling is constrained to the range $10^{-7} < g <10^{-4}$.Comment: 36 pages, 15 figure

Genus Topology of the Cosmic Microwave Background from WMAP

We have independently measured the genus topology of the temperature fluctuations in the cosmic microwave background seen by the Wilkinson Microwave Anisotropy Probe (WMAP). A genus analysis of the WMAP data indicates consistency with Gaussian random-phase initial conditions, as predicted by standard inflation.Comment: PDF: http://www.astro.virginia.edu/~wnc5c/WMAPtopology.pd

Can design documentaries disrupt design for disability?

This paper shows how design documentaries can motivate new perspectives for design and disability. We critically consider the ways in which design documentaries can foreground children's lived experiences and priorities, in cases where it is not always possible to involve children early on in the design process. By presenting a design case for supporting communication that involves children with severe speech and physical impairments and their social peers, we discuss how this narrative method can evoke designer empathy and guide new interpretations. Our findings show that design documentaries can convey to designers rich and multifaceted accounts of children's communication experiences. Although this is found to be generative, we also identify a tension with a bodily impairment understanding of disability. Drawing on reflections from our case study, we propose new methodological implications for embedding design documentaries in the design process of technologies for disability

Fine Features in the Primordial Power Spectrum

A possible origin of the anomalous dip and bump in the primordial power spectrum, which are reconstructed from WMAP data corresponding to the multipole $\ell=100\sim 140$ by using the inversion method, is investigated as a consequence of modification of scalar field dynamics in the inflation era. Utilizing an analytic formula to handle higher order corrections to the slow-roll approximation, we evaluate the relation between a detailed shape of inflaton potential and a fine structure in the primordial power spectrum. We conclude that it is unlikely to generate the observed dip and bump in the power spectrum by adding any features in the inflaton potential. Though we can make a fine enough shape in the power spectrum by controlling the feature of the potential, the amplitude of the dip and bump becomes too small in that case.Comment: 15 pages, 11 figures, submitted to JCA

CMB Power Spectrum from Noncommutative Spacetime

Very recent CMB data of WMAP offers an opportunity to test inflation models, in particular, the running of spectral index is quite new and can be used to rule out some models. We show that an noncommutative spacetime inflation model gives a good explanation of these new results. In fitting the data, we also obtain a relationship between the noncommutative parameter (string scale) and the ending time of inflation.Comment: 8 pages, 2 figures; v2: refs. added and minor corrections; v3: further minor correctio

Moduli Instability in Warped Compactifications of the Type IIB Supergravity

We show that the conifold and deformed-conifold warped compactifications of the ten-dimensional type IIB supergravity, including the Klebanov-Strassler solution, are dynamically unstable in the moduli sector representing the scale of a Calabi-Yau space, although it can be practically stable for a quite long time in a region with a large warp factor. This instability is associated with complete supersymmetry breaking except for a special case and produces significant time-dependence in the structure of the four-dimensional base spacetime as well as of the internal space.Comment: 24 pages, no figure. Typos corrected, and some arguments in section 5 are adde