1,236 research outputs found
A Note on the Optimal Structure of Production
We analyze the advantages of centralization and decentralization in industries in
which production takes place in several stages and the costs are privately observed
by the agents in charge of production. We demonstrate that "informational diseconomies"
arise when uncorrelated information is concentrated in the hands of a
single agent. These diseconomies arise when the stages of production are different
activities with different cost supports.Publicad
Aplicação SIG em incêndios florestais - FIMT (fire incident mapping tool). Caso de estudo em Portugal
Aplicação SIG em incêndios florestais - FIMT (fire incident mapping tool). Caso de estudo em Portugal
Evaporation of large black holes in AdS: greybody factor and decay rate
We consider a massless, minimally coupled scalar field propagating through
the geometry of a black 3-brane in an asymptotically space.
The wave equation for modes traveling purely in the holographic direction
reduces to a Heun equation and the corresponding greybody factor is obtained
numerically. Approximations valid in the low- and high-frequency regimes are
also obtained analytically. The greybody factor is then used to determine the
rate of evaporation of these large black holes in the context of the evaporon
model proposed in \cite{Rocha:2008fe}. This setting represents the evolution of
a black hole under Hawking evaporation with a known CFT dual description and is
therefore unitary. Information must then be preserved under this evaporation
process.Comment: 20 pages, 2 figures; v2: added references, published versio
Experiments on computer assisted optimization of the escherichia coli fermentation process using Optferm
We used the software Optferm to model and optimize the bioprocess of escherichia coli fermentation, simulating the conditions of a fed-batch bioreactor. The results, obtained by employing different AI approaches, provided useful orientation for nutrient feed strategies for increased productivity. In conclusion, we believe in silico tools can perform a rapid and valid optimization of bioprocesses avoiding expensive experiments
Scientific, Technical and Economic Committee for Fisheries. Impact assessment of multi-annual plans for Southern hake, angler fish and Nephrops (STECF-11-06)
A joint ICES / STECF meeting was held in Hamburg 20-24 June 2011, to prepare an impact assessment for Southern hake, Nerphrops and Angler fish and Baltic cod and an Evaluations of existing plans for Kattegat, North Sea, West of Scotland and Irish Sea cod. The meeting involved STECF, ICES scientists dealing with Economy and Biology and included Observers (Commission staff, Managers, Stakeholders). Three separate reports to the STECF were prepared by the EWG-11- 07, one on the Impact Assessment of Southern hake, Nerphrops and Angler fish (STECF 11-06) and the second on the Impact Assessments for Baltic cod (STECF 11-05) and the third on the Evaluation of Cod in Kattegat, North Sea, West of Scotland and Irish Sea (STECF 11-07). All reports were reviewed by the STECF during its 37th plenary meeting held from 11 to 15 July 2011 in Copenhagen, Denmark. The following observations, conclusions and recommendations represent the outcomes of that review for Southern hake, Nerphrops and Angler fish report
Coset Constructions in Chern-Simons Gauge Theory
Coset constructions in the framework of Chern-Simons topological gauge
theories are studied. Two examples are considered: models of the types
with and
coprime integers, and . In the latter
case it is shown that the Chern-Simons wave functionals can be identified with
t he characters of the minimal unitary models, and an explicit representation
of the knot (Verlinde) operators acting on the space of characters is
obtained.Comment: 15 page
Microlenses array made with AZ4562 photoresist for stereoscopic acquisition
In this paper is presented a fabrication process for obtaining refractive microlenses arrays with high reproducibility
and low cost. This process was specifically optimized for the AZ4562 photoresist. Functional prototypes of
microlenses arrays with dimensions in the range of 30 m, 4.9 mm and 5 m for width, length and thickness,
respectively, were fabricated and tested. The pre-thermal reflow spacing between adjacent isosceles trapezoids is
1.35-5.43 m, from bottom to top, respectively. This separation allows the photoresist to reflow and join the adjacent
microlens creating a consistent and homogeneous array.This work and Rui Pedro Rocha are fully supported by the Portuguese Foundation for Science and Technology under the project FCT/PTDC/EEA-ELC/109936/2009 and the financial grant SFRH/BD/33733/2009, respectively. The authors would also like to acknowledge Dr.-Ing Christian Koch from MicroChemicals GmbH for the technical support
Aportación de la densitometría ósea en las artroplastias de rodilla
El presente trabajo consiste en una revisión clínica y radiológica de 84 artroplastias
modulares de rodilla de las cuales, en 19 se ha estudiado la masa ósea periprotésica
(7 cementadas y 12 sin cementar) antes, al mes y a los seis meses de la intervención mediante
un densitómetro de doble fotón. Aparte, se ha probado la correlación directa entre la indicación
peroperatoria de no cementar y una mayor masa ósea en todas las zonas periprotésicas;
por otro lado, se ha observado una diferente distribución de la densidad mineral ósea en la
tibia tras la intervención, según se haya utilizado o no cemento. Estos hallazgos confirman el
estudio densitométrico previo a la intervención como un método complementario útil en la
indicación de la cementación de la artroplastia total de rodilla.A clinical and radiological revision of 84 modular knee arthroplasties is
presented. Periprosthesis bone mineral content was studied in 19 prostheses (7 cemented
and 12 uncemented) before, surgery one and 6 months after the intervention using a densitometer
of double energy. A direct correlation between the implantation of a non-cemented
prosthesis and the growth of the bone mass in all the periprosthesis areas was found, existing
a different distribution of the mineral bone density of the tibia after the intervention
depending on the use of cement. These findings show that the densitometric study previous
to an intervention as a useful complementary method in the indication of cemented total
knee arthroplasty
Familial pseudoxanthoma elasticum with nephrocalcinosis: a case report
Pseudoxanthoma elasticum (PXE) is an autosomal recessive genetic disorder characterized by progressive calcification and fragmentation of elastic fibres. PXE commonly involves the reticular dermis, the Bruch membrane of the eye, and blood vessels. PXE is caused by mutations in the ABCC6 gene. More than 300 pathogenic ABCC6 mutations are known. Two of these mutations are common: p.R1141X in exon 24, with a prevalence of 30%, and the Alu–mediated deletion of exons 23 to 29 (EX23_29del; p.A999_S1403del) found in 10-20% of patients. Homozygosity is rare.
A 40-year-old female with a previous diagnosis of PXE was admitted in Nephrology Outpatient Clinic for nephrocalcinosis. She has two sisters, one of which also has a diagnosis of PXE and nephrocalcinosis. Physical examination revealed the presence of typical skin and ocular abnormalities. Microscopic and gross hematuria was reported in both affected sisters. Abdominal ultrasound confirmed bilateral cortico-medullar nephrocalcinosis. Calcium and phosphorus levels in blood and urine were normal. Hyperparathyroidism, renal tubular acidosis, hypervitaminosis D and hyperoxaluria were excluded. Renal biopsy showed only minor glomerular abnormalities. Medullary sponge kidney was identified by excretory urography.
Genomic DNA was used as a template for PCR amplification of the region spanning introns 22 to 29 of ABCC6 [Pfendner et al., J Med Genet 2007;44:621-8]. The oligonucleotide cocktail used generated a 552bp PCR product for the normal sequence, and a 652bp product for the deletion mutation.
Both sisters with PXE were homozygous for the EX23_29del mutation. The third sister did not carry this deletion.
There are occasional reports of diffuse visceral calcifications (testis, mammary gland) in PXE. PXE-associated nephrocalcinosis was previously noted in four patients belonging to different families. This is the first report of familiar co-occurrence of PXE and nephrocalcinosis with medullary sponge kidney. These sisters’ peculiar phenotype could be due to their unusual genotype, or other shared genetic and environmental factors
Gravitational Energy of Kerr and Kerr Anti-de Sitter Space-times in the Teleparallel Geometry
In the context of the Hamiltonian formulation of the teleparallel equivalent
of general relativity we compute the gravitational energy of Kerr and Kerr
Anti-de Sitter (Kerr-AdS) space-times. The present calculation is carried out
by means of an expression for the energy of the gravitational field that
naturally arises from the integral form of the constraint equations of the
formalism. In each case, the energy is exactly computed for finite and
arbitrary spacelike two-spheres, without any restriction on the metric
parameters. In particular, we evaluate the energy at the outer event horizon of
the black holes.Comment: 11 pages, 1 figure, to appear in JHEP11(2003)00
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