A comparison of CFD and full-scale measurements for analysis of natural ventilation

CFD modelling techniques have been used to simulate the coupled external and internal flow in a cubic building with two dominant openings. CFD predictions of the time-averaged cross ventilation flow rates have been validated against full-scale experimental data under various weather conditions in England. RANS model predictions proved reliable when wind directions were near normal to the vent openings. However, when the fluctuating ventilation rate exceeded the mean flow, RANS models were incapable of predicting the total ventilation rate. Improved results are expected by applying more sophisticated turbulence models, such as LES or weighted quasi-steady approximations

A nighttime temperature maximum in the thermosphere above Saint Santin in winter

International audienceThe Saint Santin (45 N) incoherent scatter radar data base shows a local enhancement in nighttime ion temperature that occurs in winter only. Its amplitude can exceed 100 K and averages 40 K on the basis of a conservative computation. The enhancement peaks near 4 LT and has a duration of about 4 hours. We discuss two possible explanations for this feature: (1) it is caused by the convergence of global winds at the global pressure minimum, under which Saint Santin rotates at winter solstice, and (2) it is an extension or propagation of the well-known low-latitude midnight temperature maximum to midlatitudes, perhaps to that pressure minimum

Mining Markov Network Surrogates for Value-Added Optimisation

Surrogate fitness functions are a popular technique for speeding up metaheuristics, replacing calls to a costly fitness function with calls to a cheap model. However, surrogates also represent an explicit model of the fitness function, which can be exploited beyond approximating the fitness of solutions. This paper proposes that mining surrogate fitness models can yield useful additional information on the problem to the decision maker, adding value to the optimisation process. An existing fitness model based on Markov networks is presented and applied to the optimisation of glazing on a building facade. Analysis of the model reveals how its parameters point towards the global optima of the problem after only part of the optimisation run, and reveals useful properties like the relative sensitivities of the problem variables

Natural Inflation From Fermion Loops

``Natural'' inflationary theories are a class of models in which inflation is driven by a pseudo-Nambu-Goldstone boson. In this paper we consider two models, one old and one new, in which the potential for inflation is generated by loop effects from a fermion sector which explicitly breaks a global $U(1)$ symmetry. In both models, we retrieve the ``standard'' natural inflation potential, $V\left(\theta\right) = \Lambda^4\left[1 + \cos\left(\theta / \mu\right)\right]$, as a limiting case of the exact one-loop potential, but we carry out a general analysis of the models including the limiting case. Constraints from the COBE DMR observation and from theoretical consistency are used to limit the parameters of the models, and successful inflation occurs without the necessity of fine-tuning the parameters.Comment: (Revised) 15 pages, LaTeX (revTeX), 8 figures in uuencoded PostScript format. Version accepted for publication in Phys. Rev. D 15. Corrected definition of power spectrum and added three reference

L-VRAP-a lunar volatile resources analysis package for lunar exploration

The Lunar Volatile Resources Analysis Package (L-VRAP) has been conceived to deliver some of the objectives of the proposed Lunar Lander mission currently being studied by the European Space Agency. The purpose of the mission is to demonstrate and develop capability; the impetus is very much driven by a desire to lay the foundations for future human exploration of the Moon. Thus, LVRAP has design goals that consider lunar volatiles from the perspective of both their innate scientific interest and also their potential for in situ utilisation as a resource. The device is a dual mass spectrometer system and is capable of meeting the requirements of the mission with respect to detection, quantification and characterisation of volatiles. Through the use of appropriate sampling techniques, volatiles from either the regolith or atmosphere (exosphere) can be analysed. Furthermore, since L-VRAP has the capacity to determine isotopic compositions, it should be possible for the instrument to determine the sources of the volatiles that are found on the Moon (be they lunar per se, extra-lunar, or contaminants imparted by the mission itself

Relative sea-level change in Newfoundland, Canada during the past ∼3000 years

Several processes contributing to coastal relative sea-level (RSL) change in the North Atlantic Ocean are observed and/or predicted to have distinctive spatial expressions that vary by latitude. To expand the latitudinal range of RSL records spanning the past ∼3000 years and the likelihood of recognizing the characteristic fingerprints of these processes, we reconstructed RSL at two sites (Big River and Placentia) in Newfoundland from salt-marsh sediment. Bayesian transfer functions established the height of former sea level from preserved assemblages of foraminifera and testate amoebae. Age-depth models constrained by radiocarbon dates and chronohorizons estimated the timing of sediment deposition. During the past ∼3000 years, RSL rose by ∼3.0 m at Big River and by ∼1.5 m at Placentia. A locally calibrated geotechnical model showed that post-depositional lowering through sediment compaction was minimal. To isolate and quantify contributions to RSL from global, regional linear, regional non-linear, and local-scale processes, we decomposed the new reconstructions (and those in an expanded, global database) using a spatio-temporal statistical model. The global component confirms that 20th century sea-level rise occurred at the fastest, century-scale rate in over 3000 years (P > 0.999). Distinguishing the contributions from local and regional non-linear processes is made challenging by a sparse network of reconstructions. However, only a small contribution from local-scale processes is necessary to reconcile RSL reconstructions and modeled RSL trends. We identified three latitudinally-organized groups of sites that share coherent regional non-linear trends and indicate that dynamic redistribution of ocean mass by currents and/or winds was likely an important driver of sea-level change in the North Atlantic Ocean during the past ∼3000 years

Getting Better Hospital Alarm Sounds Into a Global Standard

The reserved set of audible alarm signals embodied within the global medical device safety standard, IEC 60601-1-8, is known to be problematic and in need of updating. The current alarm signals are not only suboptimal, but there is also little evidence beyond learnability (which is known to be poor) that demonstrates their performance in realistic and representative clinical environments. In this article, we describe the process of first designing and then testing potential replacement audible alarm signals for IEC 60601-1-8, starting with the design of several sets of candidate sounds and initial tests on learnability and localizability, followed by testing in simulated clinical environments. We demonstrate that in all tests, the alarm signals selected for further development significantly outperform the current alarm signals. We describe the process of collecting considerably more data on the performance of the new sounds than exists for the current sounds, which ultimately will be of use to end users. We also reflect on the process and practice of working with the relevant committees and other practical issues beyond the science, which also need constant attention if the alarms we have developed are to be included successfully in an updated version of the standard

Strain-specific copy number variation in the intelectin locus on the 129 mouse chromosome 1

<p>Abstract</p> <p>Background</p> <p>C57BL/6J mice possess a single <it>intelectin (Itln) </it>gene on chromosome 1. The function of intelectins is not well understood, but roles have been postulated in insulin sensitivity, bacterial recognition, intestinal lactoferrin uptake and response to parasites and allergens. In contrast to C57BL/6J mice, there is evidence for expansion of the <it>Itln </it>locus in other strains and at least one additional mouse <it>Itln </it>gene product has been described. The aim of this study was to sequence and characterise the <it>Itln </it>locus in the 129S7 strain, to determine the nature of the chromosomal expansion and to inform possible future gene deletion strategies.</p> <p>Results</p> <p>Six 129S7 BAC clones were sequenced and assembled to generate 600 kbp of chromosomal sequence, including the entire <it>Itln </it>locus of approximately 500 kbp. The locus contained six distinct <it>Itln </it>genes, two <it>CD244 </it>genes and several <it>Itln</it>- and <it>CD244</it>-related pseudogenes. It was approximately 433 kbp larger than the corresponding C57BL/6J locus. The expansion of the <it>Itln </it>locus appears to have occurred through multiple duplications of a segment consisting of a full-length <it>Itln </it>gene, a <it>CD244 </it>(pseudo)gene and an <it>Itln </it>pseudogene fragment. Strong evidence for tissue-specific distribution of <it>Itln </it>variants was found, indicating that <it>Itln </it>duplication contributes more than a simple gene dosage effect.</p> <p>Conclusions</p> <p>We have characterised the <it>Itln </it>locus in 129S7 mice to reveal six <it>Itln </it>genes with distinct sequence and expression characteristics. Since C57BL/6J mice possess only a single <it>Itln </it>gene, this is likely to contribute to functional differences between C57BL/6J and other mouse strains.</p

In vitro anthelmintic effect of plant extracts against infective larvae of ruminants gastrointestinal nematode parasites

With the purpose of studying the anthelmintic efficacy of some plant species presents in Queensland State, Australia, we tested in vitro the effect of plant extracts on infective larvae (L3) migration of Haemonchus placei, Cooperia sp., Haemonchus contortus and Trichostrongylus colubriformis. In general, plant extracts reduced the larval migration of Haemonchus placei and Cooperia sp. The most effective plants against Haemonchus placei and Cooperia sp. (P < 0.0001) were Allocasuarina torulosa, Neolitsea dealbata, Acacia holosericea, Acacia salicina, Callitris endlicheri and Casuarina cunninghamiana. Plants extracts were less effective on L3 migration of Haemonchus contortus and Trichostrongylus colubriformis. Callitris endlicheri, Casuarina cunninghamiana, Acacia farnesiana, Acacia holosericea and Acacia nilotica were the plant extracts that shown an important larval migration inhibition against H. contortus and Trichostrongylus colubriformis (P < 0.0001). Callitris endlicheri was the plant that consistently inhibited the larval migration of every nematode species under study. These in vitro results suggest anthelmintic properties associate with some of the plant species we studied.EEA Cerro AzulFil: Moreno, Fabiana Carina. University Drive. CSIRO Davies Laboratory; Australia. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad Ciencias Veterinarias; Argentina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Montecarlo; ArgentinaFil: Gordon, Iain J. University Drive. CSIRO Davies Laboratory; AustraliaFil: Wright, A.D. AIMS Australian Institute of Marine Science; AustraliaFil: Benvenutti, Marcelo. University Drive. CSIRO Davies Laboratory; Australia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Montecarlo; ArgentinaFil: Saumell, Carlos A. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad Ciencias Veterinarias; Argentin

Large Scale Structure and Supersymmetric Inflation without Fine Tuning

We explore constraints on the spectral index $n$ of density fluctuations and the neutrino energy density fraction $\Omega_{HDM}$, employing data from a variety of large scale observations. The best fits occur for $n\approx 1$ and $\Omega_{HDM} \approx 0.15 - 0.30$, over a range of Hubble constants $40-60$ km s$^{-1}$ Mpc$^{-1}$. We present a new class of inflationary models based on realistic supersymmetric grand unified theories which do not have the usual `fine tuning' problems. The amplitude of primordial density fluctuations, in particular, is found to be proportional to $(M_X /M_P)^2$, where $M_X (M_P)$ denote the GUT (Planck) scale, which is reminiscent of cosmic strings! The spectral index $n = 0.98$, in excellent agreement with the observations provided the dark matter is a mixture of `cold' and `hot' components.Comment: LaTEX, 14 pp. + 1 postscript figure appende