2,525 research outputs found
Issues for computer modelling of room acoustics in non-concert hall settings
The basic principle of common room acoustics computer models is the energy-based geometrical room acoustics theory. The energy-based calculation relies on the averaging effect provided when there are many reflections from many different directions, which is well suited for large concert halls at medium and high frequencies. In recent years computer modelling has become an established tool in architectural acoustics design thanks to the advance in computing power and improved understanding of the modelling accuracy. However concert hall is only one of many types of built environments that require good acoustic design. Increasingly computer models are being sought for non-concert hall applications, such as in small rooms at low frequencies, flat rooms in workplace surroundings, and long enclosures such as underground stations. In these built environments the design issues are substantially difference from that of concert halls and in most cases the common room acoustics models will needed to be modified or totally re-formulated in order to deal with these new issues. This paper looks at some examples of these issues. In workplace environments we look at the issues of directional propagation and volume scattering by furniture and equipment instead of the surface scattering that is common assumed in concert hall models. In small rooms we look at the requirement of using wave models, such as boundary element models, or introducing phase information into geometrical room acoustics models to determine wave behaviours. Of particular interest is the ability of the wave models to provide phase information that is important not only for room modes but for the construction of impulse response for auralisation. Some simulated results using different modelling techniques will be presented to illustrate the problems and potential solutions
Construction of Infrared Finite Observables in N=4 Super Yang-Mills Theory
In this paper we give all the details of the calculation that we presented in
our previous paper ArXiv:0908.0387 where the infrared structure of the MHV
gluon amplitudes in the planar limit for super Yang-Mills theory
was considered in the next-to-leading order of perturbation theory. Explicit
cancellation of the infrared divergencies in properly defined inclusive
cross-sections is demonstrated first in a toy model example of "conformal QED"
and then in the real SYM theory. We give the full-length details
both for the calculation of the real emission and for the diagrams with
splitting in initial and final states. The finite parts for some inclusive
differential cross-sections are presented in an analytical form. In general,
contrary to the virtual corrections, they do not reveal any simple structure.
An example of the finite part containing just the log functions is presented.
The dependence of inclusive cross-section on the external scale related to the
definition of asymptotic states is discussed.Comment: 49 pages, LATEX, 6 eps figures; Minor changes, Refs adde
Readout and Control of a Power-recycled Interferometric Gravitational-wave Antenna
Interferometric gravitational wave antennas are based on Michelson
interferometers whose sensitivity to small differential length changes has been
enhanced by adding multiple coupled optical resonators. The use of optical
cavities is essential for reaching the required sensitivity, but sets
challenges for the control system which must maintain the cavities near
resonance. The goal for the strain sensitivity of the Laser Interferometer
Gravitational-wave Observatory (LIGO) is 10^-21 rms, integrated over a 100 Hz
bandwidth centered at 150 Hz. We present the major design features of the LIGO
length and frequency sensing and control system which will hold the
differential length to within 5 10^-14 m of the operating point. We also
highlight the restrictions imposed by couplings of noise into the gravitational
wave readout signal and the required immunity against them.Comment: Presentation at ICALEPCS 2001, San Jose, November 2001, (WECT003), 3
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Exploring the chemical fate of the sulfate radical anion by reaction with sulfur dioxide in the gas phase
Diagnosis and treatment of hereditary angioedema with normal C1 inhibitor
Until recently it was assumed that hereditary angioedema is a disease that results exclusively from a genetic deficiency of the C1 inhibitor. In 2000, families with hereditary angioedema, normal C1 inhibitor activity and protein in plasma were described. Since then numerous patients and families with that condition have been reported. Most of the patients by far were women. In many of the affected women, oral contraceptives, hormone replacement therapy containing estrogens, and pregnancies triggered the clinical symptoms. Recently, in some families mutations in the coagulation factor XII (Hageman factor) gene were detected in the affected persons
Disentangling genetic and environmental effects on the proteotypes of individuals
Proteotypes, like genotypes, have been found to vary between individuals in several studies, but consistent molecular functional traits across studies remain to be quantified. In a meta-analysis of 11 proteomics datasets from humans and mice, we use co-variation of proteins in known functional modules across datasets and individuals to obtain a consensus landscape of proteotype variation. We find that individuals differ considerably in both protein complex abundances and stoichiometry. We disentangle genetic and environmental factors impacting these metrics, with genetic sex and specific diets together explaining 13.5% and 11.6% of the observed variation of complex abundance and stoichiometry, respectively. Sex-specific differences, for example, include various proteins and complexes, where the respective genes are not located on sex-specific chromosomes. Diet-specific differences, added to the individual genetic backgrounds, might become a starting point for personalized proteotype modulation toward desired features
Nonbreast-fed, HIV-1-exposed Burkinabe infants have low energy intake between 6 and 11 months of age despite free access to infant food aid
In a WHO coordinated, mother-to-child HIV transmission (MTCT) prevention trial in Burkina Faso, HIV-1 nfected mothers were adv sed to either stop breast-feeding oy 6 mo or totally avoid it. Participants were prov ded with cereal-based, infant fortified mix (IFM) from 6 to 12 mo postpartum along with infant feeding counseling. Our objective was to describe ronbreast-fed infants food consumption and adecuacy of nutrient intake. A 1-d weighed food record and one 24 h dietary recall were performed in 68 nonbreast-fed, non-HIV infected 6- to 11-mo-old infants. Mean food enemy density and feeding frequency were satisfactory n 6-8 mo ods [0.8 +/- 0.2 kcal/g (3.3 +/- 0.9 kJ/g) and 7.2 +/- 1.6 times/c] and n 9-11 moods [0.9 +/- 0.2 kcal/lg (3.6 +/- 0.8 kJ/g) and 7.7 +/- 2 1 times/d]. Median energy intake was 523 Kcal [range 82-1053 (2187 kJ, range: 345-4401)] in 6-8- and 811 kcal [range: 34-1543 (3392 kJ, range: 144-6452)] n 9-11-mo-old infants, respectively. Approximately 75% of their energy intake was provided by subsidized foods (milk that mothers obta ned from support networks and IFM). One-has of the infants had intakes < 80 kcal/kg (<334 kJ/kg) on the day of the survey, mainly because IFM and milk were consumed in amounts that were too low. Thus, coverage of energy needs required a diet with sufficient amounts of both IFM and milk in these vulnerable infants. These findings argue for the development of adequate, sustainable infant fort fed foods and their rapid integration into MTCT prevent on services They also lend support to the recent revision of WHO infant feeding guidance for future MTCT prevention programming that recommends breast-feeding up to 12 me postpartum (under cover of antiretroviral prophylaxis) as the safest feeding option for infants of HIV-infected mothers. J. Nutr. 141: 674-679, 2011
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