The Pulsed Neutron Beam EDM Experiment

We report on the Beam EDM experiment, which aims to employ a pulsed cold neutron beam to search for an electric dipole moment instead of the established use of storable ultracold neutrons. We present a brief overview of the basic measurement concept and the current status of our proof-of-principle Ramsey apparatus

Formation of supermassive stars in the first star clusters

The formation of supermassive stars is believed to be an essential intermediate step for the formation of the massive black hole seeds that become the supermassive black holes powering the quasars observed in the early Universe. Numerical simulations have shown that supermassive stars can form in atomic-cooling halos when protostars reach accretion rates higher than $\sim10^{-2}$ M$_\odot$ yr$^{-1}$ and fragmentation is suppressed on pc scales. It is however still uncertain if a supermassive star still emerges when fragmentation occurs at smaller scales and a cluster of stars is formed instead. In this work we explore the problem of massive object formation due to the interplay of collisions and accretion in star clusters at low metallicity. We model a small embedded cluster of accreting protostars following sub-parsec scale fragmentation during the collapse of a primordial gas cloud and follow its evolution by performing $N$-body plus hydrodynamical simulations. Our results show that supermassive stars with 10$^3$ and 10$^4$ M$_\odot$ are always formed due to the interplay of collisions and accretion, and in some cases these objects are part of a binary system. The resulting supermassive star is surrounded by tens of smaller stars with typical masses in the range $1$-$100$ M$_\odot$.Comment: 16 pages, 20 figures, accepted by MNRA

Impacto de la eficiencia en el consumo de biomasa en el sector celulosa chileno

On the basis of official statistics, and data obtained directly of the companies of the sector cellulose Kraft, there are shown the characteristics of the use of biomass like energetic waste matter used by the sector. There are identified volumes, sources, costs and there are obtained Specific Consumer’s indicators of Energy, for type of energy, and the impact of the efficiency in the generation of electricity. The most relevant aspects of the study reflect an inadequate energetic management and incorporation of technology only with objectives of physical increase of the production without an exact conscience that all energy saved in processes is possible to sell it as electricity. The impact of a use at minor levels of efficiency, in the consumption of energy, meant for the year 2002 a reduction of sales of surpluses of electricity of about 85%.En base a estadísticas oficiales, y datos obtenidos directamente de las empresas del sector celulosa Kraft, se exponen las características de biomasa como desechos energéticos utilizados por el sector. Se identifican volúmenes, fuentes, costos y se obtienen indicadores de Consumo Específico de Energía, por tipo de energía, y el impacto de la eficiencia en la generación de electricidad. Los aspectos más relevantes del estudio reflejan una inadecuada gestión energética e incorporación de tecnología sólo con objetivos de aumento físico de la producción, sin tener en consideración de que toda energía ahorrada en procesos es posible venderla como electricidad. El impacto de un uso a menores niveles de eficiencia, en el consumo de energía, significó en el año 2002 menores venta de excedentes de electricidad del orden de un 85%

A Genetic Programming infrastructure profiting from public computation resources

In this article an experience of the utilization of PRC (Public Resource Computation) in research projects that needs large quantities of CPU time is presented. We have developed a distributed architecture based on middleware BOINC and LilGP Genetic Programming tool. In order to run LilGP applications under BOINC platforms, some core LilGP functions has been adapted to BOINC requirements. We have used a classic GP problem known as the artificial ANT in Santa Fe Trail. Some computers from a classroom were used acting as clients, proving that they can be used for scientific computation in conjunction with their primary uses

Learning Moore Machines from Input-Output Traces

The problem of learning automata from example traces (but no equivalence or membership queries) is fundamental in automata learning theory and practice. In this paper we study this problem for finite state machines with inputs and outputs, and in particular for Moore machines. We develop three algorithms for solving this problem: (1) the PTAP algorithm, which transforms a set of input-output traces into an incomplete Moore machine and then completes the machine with self-loops; (2) the PRPNI algorithm, which uses the well-known RPNI algorithm for automata learning to learn a product of automata encoding a Moore machine; and (3) the MooreMI algorithm, which directly learns a Moore machine using PTAP extended with state merging. We prove that MooreMI has the fundamental identification in the limit property. We also compare the algorithms experimentally in terms of the size of the learned machine and several notions of accuracy, introduced in this paper. Finally, we compare with OSTIA, an algorithm that learns a more general class of transducers, and find that OSTIA generally does not learn a Moore machine, even when fed with a characteristic sample

Performance and durability of broadband antireflection coatings for thin film CdTe solar cells

Light reflection from the glass surface of a photovoltaic (PV) module is a significant source of energy loss for all types of PV devices. The reflection at the glass and air interface accounts for 4% of the total energy. Single layer antireflection coatings with sufficiently low refractive index have been used, such as those using magnesium fluoride or porous silica, but these are only effective over a narrow range of wavelengths. In this paper, the authors report on the design, deposition, and testing of multilayer broadband antireflection coatings. These coatings reduce the weighted average reflection over the wavelength range used by thin film CdTe devices to just 1.22%, resulting in a 3.6% relative increase in device efficiency. The authors have used multilayer stacks consisting of silica and zirconia layers deposited using reactive magnetron sputtering. Details of the stack design, sputter deposition process parameters, and the optical and microstructural properties of the layers are provided. Antireflection coatings on glass exposed to the outdoors must not degrade over the lifetime of the module. A comprehensive set of accelerated environmental durability tests has been carried out in accordance with IEC 61646 PV qualification tests. The durability tests confirmed no damage to the coatings or performance drop as a result of thermal cycling or damp heat. All attempts to perform pull tests resulted in either adhesive or substrate failure, with no damage to the coating itself. The coatings also passed acid attack tests. Scratch resistance, abrasion resistance, and adhesion tests have also been conducted. The optical performance of the coatings was monitored during these tests, and the coatings were visually inspected for any sign of mechanical failure. These tests provide confidence that broadband antireflection coatings are highly durable and will maintain their performance over the lifetime of the solar module. All dielectric metal-oxide multilayer coatings have better optical performance and superior durability compared with alternative single layer porous sol–gel coatings. Thin film CdTe devices are particularly problematic because the antireflection coating is applied to one side of the glass, while device layers are deposited directly on to the opposite glass surface in the superstrate configuration. In thin film CdTe production, the glass is exposed to high temperature processes during the absorber deposition and the cadmium chloride activation treatment. If glass precoated with a broadband antireflection coating is to be used, then the coating must withstand temperatures of up to 550 C. Surprisingly, our studies have shown that multilayer silica/zirconia antireflection coatings on soda lime glass remain unaffected by temperatures reaching 600 C, at which point mild crazing is observed. This is an important observation, demonstrating that low cost glass, which is preprocessed with a broadband antireflection coating, is directly useable in thin film CdTe module production

Melatonin expression in periodontal disease

It was the purpose of this study to examine the relationship between periodontal diseases and melatonin level. Material and Methods:  Forty-six patients with periodontal disease, together with 26 age- and gender-matched healthy controls, were included. Periodontal status was assessed using the Community Periodontal Index. Plasma and salivary melatonin levels were determined using specific commercial radioimmunoassays, whereas lymphocyte subpopulations (e.g. CD3, CD4, CD8, C19 and natural killer cells) were analyzed using flow cytometry. Results:  Patients with periodontal disease had significantly ( p <  0.001) lower plasma (9.46 ± 3.18 pg/mL) and saliva (2.55 ± 0.99 pg/mL) melatonin levels than healthy control patients (14.33 ± 4.05 and 4.22 ± 0.87 pg/mL, respectively). A biphasic relationhip was observed between plasma melatonin levels and Community Periodontal Indices. The plasma melatonin level was reduced in patients with a lower Community Periodontal Index value (1 or 2) and increased in patients with a higher Community Periodontal Index value (3 or 4). Salivary melatonin parallels the changes of plasma melatonin. The higher the Community Periodontal Index, the older the patient and the higher the total lymphocyte counts. CD4 concentrations also increased as the disease worsened. Conclusion:  The results obtained from this study suggest that melatonin could act as a protective function in fighting periodontal infection. However, further studies in this area are encouraged.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65967/1/j.1600-0765.2007.00978.x.pd

Utilización de Internet para la enseñanza de sistemas digitales

Las nuevas tecnologías de la información y la comunicación han creado grandes expectativas en educación, pues permiten superar las limitaciones de tiempo y lugar, abaratando incluso los costes. Además, no debe olvidarse que los medios informáticos ofrecen una serie de características que favorecen el aprendizaje significativo a través de actividades de tipo interactivo. Por eso, nos parece importante su aplicación a la enseñanza de la Informática, y en particular de los sistemas digitales. En esta ponencia se presenta un sistema multimedia, basado en Internet, que se está desarrollando con el fin de aplicarlo a la docencia de sistemas digitales en la asignatura Fundamentos de Informática. La ponencia presenta una descripción general de dicho sistema, así como de las herramientas y métodos utilizados para su construcción