1,141 research outputs found
Lattice calculations on the spectrum of Dirac and Dirac-K\"ahler operators
We present a matrix technique to obtain the spectrum and the analytical index
of some elliptic operators defined on compact Riemannian manifolds. The method
uses matrix representations of the derivative which yield exact values for the
derivative of a trigonometric polynomial. These matrices can be used to find
the exact spectrum of an elliptic operator in particular cases and in general,
to give insight into the properties of the solution of the spectral problem. As
examples, the analytical index and the eigenvalues of the Dirac operator on the
torus and on the sphere are obtained and as an application of this technique,
the spectrum of the Dirac-Kahler operator on the sphere is explored.Comment: 11 page
The Assembly of the LHC Short Straight Sections at CERN: Work Organization, Quality Assurance and Lessons Learned
After 4 years of activity, the assembly of approximately 500 Short Straight Sections (SSS) for the LHC has come to an end at the beginning of 2007. This activity, which was initially foreseen in European industry, was in-sourced at CERN because of the insolvency of the prime contractor. While the quadrupole cold masses were produced in industry, the assembly within their cryostats was transferred to CERN and executed by an external company under a result-oriented contract. CERN procured cryostat components, set up a dedicated 2000 m2 assembly hall with all the specific assembly equipment and tooling and defined the assembly and testing procedures. The contractor took up responsibility for the delivery, on time, of assemblies according to the required quality. A dedicated CERN production and quality assurance team was constituted. A specific quality assurance plan was set up involving 2 additional contractors responsible for weld inspections on a total of about 20'000 assembly welds and the execution of about 3300 leak detection tests. This paper presents the organizational aspects of the activity and the experience gained throughout the production. The learning curves and statistics by type of non-conformities detected and general quality assurance aspects are presented and discussed. The main lessons learnt are summarized, in an attempt to draw some conclusions which could be useful in making strategic choices for the cryostat assembly in future large-scale accelerators
Effect of immature oak (Quercus pyrenaica) leaves intake on ruminal fermentation and adaptation of rumen microorganisms in cattle
6 pages, 2 figures.-- Contributed to: VII International Symposium on the Nutrition of Herbivores (Beijing, China, Sep 17−22, 2007).Later published as paper in: Animal Feed Science and Technology 150(1-2): 75-85 (2009), https://digital.csic.es/handle/10261/13289Two experiments were conducted to study the effect of the consumption of different amounts
of immature Pyrenean oak leaves (OL) by beef cattle on in vitro ruminal fermentation and potential
adaptation of rumen microorganisms. A total of twelve ruminally cannulated young Brown Swiss bulls
were divided in experimental groups that received different amounts of OL via the ruminal cannula (on
average 0, 2.5, 5.2 and almost 10 kg fresh matter per animal and day). The gas production technique
was used to study in vitro fermentation of two substrates (grass hay and OL) incubated with rumen
inocula derived from each bull. Results suggest not only a dose-dependent negative effect of tannins
consumption on ruminal fermentation of common feeds (e.g., grass hay), but also an adaptation of
rumen microbial populations from animals receiving moderate amounts of OL. The high level of
tannins in the rumen of bulls that received the highest amount of OL would have exceeded the ability
of microorganisms to tolerate or detoxify them.Supported by the Spanish Ministry of Education and Science, MEC, Project AGL2004-06076-C02-01Peer reviewe
Depth of focus increase by multiplexing programmable diffractive lenses
A combination of several diffractive lenses written onto a single programmable liquid crystal display (LCD) is proposed for increasing the Depth of Focus (DOF) of the imaging system as a whole. The lenses are spatially multiplexed in a random scheme onto the LCD. The axial irradiance distribution produced by each lens overlaps with the next one producing an extended focal depth. To compare the image quality of the multiplexed lenses, the Modulation Transfer Function (MTF) is calculated. Finally we obtain the experimental Point Spread Functions (PSF) for these multiplexed lenses and experimental results in which an extended object is illuminated under spatially incoherent monochromatic light. We compare the images obtained in the focal plane and in some defocused planes with the single lens and with three multiplexed lenses. The experimental results confirm that the multiplexed lenses produce a high increase in the depth of focus.Fil: Iemmi, Claudio Cesar. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Campos, Juan. Universitat Autonoma de Barcelona; EspañaFil: Escalera, J. C.. Universitat Autonoma de Barcelona; EspañaFil: López Coronado, O. Universitat Autonoma de Barcelona; EspañaFil: Gimeno, R.. Universitat Autonoma de Barcelona; EspañaFil: Yzuel, María J.. Universitat Autonoma de Barcelona; Españ
Feed intake and performance of growing lambs raised on concentrate-based diets under cafeteria feeding systems
8 pages, 4 tables, 3 figures.--Two trials were undertaken to study the effects of cafeteria feeding systems on the feed intake, animal performance and carcass characteristics of growing lambs, Trial 1 was designed to compare conventional and cafeteria feeding systems in terms of the growth of individually reared lambs. For this assay, 26 weaned Merino lambs (15.5 +/- 0.20 kg live weight) were assigned to three dietary treatment groups: (1) a control group fed barley straw and commercial concentrate under a conventional feeding system, (2) group W100S, fed soya-bean meal, whole barley grain and a mineral-vitamin supplement under a cafeteria feeding system, and (3) group W100S-T, fed as in the W100S treatment but allowing the lambs an initial training period so they could learn to identify a number of feeds. The feeding system had no significant effect (P > 0.05) on either average daily live-weight gain, carcass weight, or carcass conformation. The food conversion ratio was lower (P < 0.05) for the cafeteria-reared animals (2.9 +/- 0.16 v. 2.5 +/- 0.08g dry-matter intake per g average daily gain) than those of the control group. This might be related to the higher crude protein intake seen in the cafeteria groups (150 +/- 5.6 v. 208 +/- 12.5g per animal per day, P < 0.001).
In trial 2, cafeteria and conventional feeding system were compared in terms of the growth of feedlot lambs. Two hundred weaned Merino lambs (13.1 +/- 0.10 kg) were divided into two experimental groups: (1) a control group, offered commercial concentrate and barley straw, and (2) a cafeteria group fed the same diet as W100ST in trial 1. The average daily gain (282 +/- 5.8 and 309 6.5, P 0.001) in the conventional than in the cafeteria system lambs.
The use of cafeteria systems for fattening lambs can improve the feed conversion efficiency and body growth rate over those achieved with conventional feeding systems, although the crude protein intake in these systems seems to be in excess of requirements.This research was funded by Magnus S.A., with additional
support from the collaboration between Caja España and the
Estación Agrícola Experimental (CSIC, Spanish National
Research Council).Peer reviewe
Solution to the Reliability Problem of Radial Electric Distribution Systems Through Artificial Intelligence
In this paper the distribution electric system reliability is recognized like an artificial intelligence problem. How this idea is applied in evaluation of reliability is detailed. Concepts as Intelligence Matrix and Inter-feeder Route are defined. From the last one a reliability prediction strategy for medium voltage networks is proposed and tested
Informe automático y análisis de reproducibilidad de experimentos proteómicos cualitativos mediante la herramienta "MIAPE extractor"
Comunicaciones a congreso
Sphere rolling on the surface of a cone
We analyse the motion of a sphere that rolls without slipping on a conical
surface having its axis in the direction of the constant gravitational field of
the Earth. This nonholonomic system admits a solution in terms of quadratures.
We exhibit that the only circular of the system orbit is stable and furthermore
show that all its solutions can be found using an analogy with central force
problems. We also discuss the case of motion with no gravitational field, that
is, of motion on a freely falling cone.Comment: 12 pages, 2 figures, to be published in Eur J Phy
Distribution of alpha1 antitrypsin rare alleles in six countries: Results from the Progenika diagnostic network
Alpha1 antitrypsin deficiency; Diagnosis; Rare allelesDèficit d'alfa1 antitripsina; Diagnòstic; Al·lels rarsDéficit de alfa1 antitripsina; Diagnóstico; Alelos rarosBackground
Knowledge of the frequency of rare SERPINA1 mutations could help in the management of alpha1 antitrypsin deficiency (AATD). The present study aims to assess the frequencies of rare and null alleles and their respiratory and hepatic pathogenicity.
Methods
This is a secondary analysis of a study that evaluated the viability of the Progenika diagnostic genotyping system in six different countries by analyzing 30,827 samples from cases of suspected AATD. Allele-specific genotyping was carried out with the Progenika A1AT Genotyping Test which analyses 14 mutations in buccal swabs or dried blood spots samples. SERPINA1 gene sequencing was performed for serum AAT-genotype discrepancies or by request of the clinician. Only cases with rare mutations were included in this analysis.
Results
There were 818 cases (2.6%) carrying a rare allele, excluding newly identified mutations. All were heterozygous except for 20 that were homozygous. The most frequent alleles were the M-like alleles, PI*Mmalton and PI*Mheerlen. Of the 14 mutations included in the Progenika panel, there were no cases detected of PI*Siiyama, PI*Q0granite falls and PI*Q0west. Other alleles not included in the 14-mutation panel and identified by gene sequencing included PI*Mwürzburg, PI*Zbristol, and PI*Zwrexham, and the null alleles PI*Q0porto, PI*Q0madrid, PI*Q0brescia, and PI*Q0kayseri.
Conclusions
The Progenika diagnostic network has allowed the identification of several rare alleles, some unexpected and not included in the initial diagnostic panel. This establishes a new perspective on the distribution of these alleles in different countries. These findings may help prioritize allele selection for routine testing and highlights the need for further research into their pathogenetic role
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