Human enteric viruses in the water environment: a minireview

Water virology started around half a century ago, with scientists attempting to detect poliovirus in water samples. Since that time, other enteric viruses responsible for gastroenteritis and hepatitis, among a great variety of virus strains, have replaced enteroviruses as the main target for detection in the water environment. Technical molecular developments, polymerase-chain reaction (PCR) amplification being the method of choice, enable the detection of fastidious health-significant viruses. However, shortcomings of molecular procedures include their potential incompatibility with concentration methods, indispensable to reduce the water sample volume to assay for viruses, and the inability to discern between infectious and non infectious material. On the other hand, these procedures are restrained to sophisticated laboratories and detection of alternative indicator organisms has been proposed. Bacterial indicators fail to give a reliable clue of the virological quality of water. Selected bacteriophage groups appear as a better choice for their use as virus indicators

Virus emergents

No fa massa es creia que el risc derivat de les malalties infeccioses seria aviat un tema del passat, gràcies als avenços en medicina i higiene. Avui en dia, ja en el nou mil·leni res està més lluny de la realitat.Mentre que les malalties infeccioses segueixen sent la primera causa de mortalitat globalment en tot el món, i la tercera causa de mortalitat en països desenvolupats, van apareixent cada cop amb més freqüència noves malalties causades per patògens de recent descobriment o per la reaparició d'agents que es creien eradicats o en via d'eradicació. De tots els patògens emergents destaquen per nombre i importància els virus que han estat responsables de l'aparició de malalties com la sida, algunes febres hemorràgiques com l'Ebola, el dengue o Lassa, el SARS i, més recentment, la grip aviària.Some time ago, it was believed that medicine and hygiene advances would give up with risks arising from infective diseases, nevertheless, the world today is far from that expectation.Whereas infective diseases are still globally worldwide the first death cause, and the third cause of mortality at developed countries, new diseases are appearing more frequently, caused both by recently discovered pathogens or reappeared agents believed eradicated or in the way of eradication.Within emergent pathogens, we remark, basing on number and prevalence, viruses such as those causing AIDS, some hemorrhagic fevers as Ebola, dengue or Lassa, SARS, and recently chicken influenza

Study of the benefits and applications of passenger supersonic transport vehicles: case study of Supersonic 2.0-Virgin Galactic

The commercial supersonic passenger transport business has regained momentum in recent years. With the emergence and development of state-of-the-art technologies, many aerospace companies are now confident of being able to overcome all the technical and economic problems experienced by Concorde, the last supersonic aircraft to operate commercially and the benchmark for all current designs. In this sense, aspects such as the reduction of operating and maintenance costs, the ability to adapt to existing airport infrastructures and compliance with international regulations will be key to the success of the business. In addition, today’s companies will have to face the new challenges of today’s mobility, such as efficiency and sustainability. This study provides an overview, as well as a subsequent global comparison, of the different solutions presented by the various companies that are expected to enter the market in the coming years, consisting of supersonic and hypersonic aircraft capable of delivering performances that were unthinkable just a few years ago, such as being able to travel from London to New York in just 90 minutes in a safe, comfortable and sustainable manner. On the other hand, the study later focuses on a much deeper analysis of the world’s first commercial spaceline, Virgin Galactic, and the business model it is intended to implement for the commercial supersonic transport market. This analysis provides an overview of the company that enables to see how, although Virgin Galactic currently focuses the vast majority of its technological, human and economic resources on the space travel business, the company could take advantage of the capabilities, technologies and expertise developed within this business to be capable of successfully implementing its business model for the supersonic commercial travel market, the Supersonic 2.0 business model. The detailed study of this business model using the Business Model Canvas tool allows to identify the key aspects for its operation, as well as the differential features that the company should enhance. Finally, it is observed that Virgin Galactic, as well as most of its competitors, will have to be able to overcome the many risks inherent in the passenger supersonic transport market. For this reason, the company’s ability to demonstrate the safety, efficiency and sustainability of its design will be crucial to gaining consumer confidence

Finding a suitable catalyst for on-board ethanol reforming using exhaust heat from an internal combustion engine

Ethanol steam reforming with pure ethanol and commercial bioethanol (S/C = 3) was carried out inside the housing of the exhaust gas pipe of a gasoline internal combustion engine (ICE) by using exhaust heat (610–620 °C). Various catalytic honeycombs loaded with potassium-promoted cobalt hydrotalcite and with ceria-based rhodium–palladium catalysts were tested under different reactant loads. The hydrogen yield obtained over the cobalt-based catalytic honeycomb at low load (F/W 200 h) at high load (F/W = 150 mLliq·gcat-1·h-1, GHSV = 2.4·103 h-1) showed that promotion of the ceria-supported noble metal catalyst with alumina and zirconia is a key element for practical application using commercial bioethanol. HRTEM analysis of post mortem honeycombs loaded with RhPd/Ce0.5Zr0.5O2–Al2O3 showed no carbon formation and no metal agglomeration.Postprint (author's final draft

High-energy emission from jet-clump interactions in microquasars

High-mass microquasars are binary systems consisting of a massive star and an accreting compact object from which relativistic jets are launched. There is considerable observational evidence that winds of massive stars are clumpy. Individual clumps may interact with the jets in high-mass microquasars to produce outbursts of high-energy emission. Gamma-ray flares have been detected in some high-mass X-ray binaries, such as Cygnus X-1, and probably in LS 5039 and LS I+61 303. We predict the high-energy emission produced by the interaction between a jet and a clump of the stellar wind in a high-mass microquasar. Assuming a hydrodynamic scenario for the jet-clump interaction, we calculate the spectral energy distributions produced by the dominant non-thermal processes: relativistic bremsstrahlung, synchrotron and inverse Compton radiation, for leptons, and for hadrons, proton-proton collisions. Significant levels of emission in X-rays (synchrotron), high-energy gamma rays (inverse Compton), and very high-energy gamma rays (from the decay of neutral pions) are predicted, with luminosities in the different domains in the range ~ 10^{32}-10^{35} erg/s. The spectral energy distributions vary strongly depending on the specific conditions. Jet-clump interactions may be detectable at high and very high energies, and provide an explanation for the fast TeV variability found in some high-mass X-ray binary systems. Our model can help to infer information about the properties of jets and clumpy winds by means of high-sensitivity gamma-ray astronomy.Comment: Accepted for publication in A&A (10 pages, 8 figures

Notes sobre el passat, el present i el futur de les pinedes de pi roig (Pinus sylvestris L.) de les Muntanyes de Prades: resultats d'un estudi dendroecològic

En aqucst treball s'analitza des del punt de vista de la successió ecològica l'estructura demogràfica, la producció i el vigor de la població de Pinus sylvestris que cobreix les parts altes del bosc de Poblet (Muntanyes de Prades, Serralada Prelitoral catalana). L'edat dels arbres revela que formen una sola cohort que va començar a envair la zona al voltant del 1848, cosa que denota la forta pertorbació a que devia ser sotmès el bosc pel temps de la desamortització (1835). L'absència de regeneració de P. Sylvestris i la seva producció i vigor extremament baixos suggereixen que la població d'aquesta espècie, malgrat ser la que ara domini el paisatge, es troba en una clara fase de decadència i es pot preveure la seva pròxima substitució per una ja abundant regeneració de Quercus ilex i Q. Pyrenaica, tolerants a l'ombra. A través de les sèries de creixements anuals dels arbres i de les distribucions d'edat i de diàmetres s'evidencien les diferents fases de desenvolupament per les quals ha passat el bosc, condicionades per la interacció entre la mateixa dinàmica de la vegetació i les diferents actuations de l'home. Finalment, el fet que un sol episodi de pertorbació permeti l'establiment i la persistència d'una pineda durant cent cinquanta anys o més es una dada d'interès més enllà de 1'entorn estricte de les Muntanyes de Prades i que pot servir per interpretar bona part del paisatge mediterrani actual de Catalunya.The demographic structure, primary production and tree vigor of the population of Pinus sylvestris covering the upper slopes of the Poblet forest (Prades mountains, in the precoastal Catalan range) is analyzed from a successional point of view. Tree ages reveal that they form a single cohort which started invading the site by 1848, thus indicating a severe disturbance period probably related to the 1835 disentailment law. The lack of regeneration of P. sylvestris and the extremely low production and vigor of adult pine trees suggest that the population of this species, although now dominant in the landscape, is actually undergoing a clear decline, and its replacement by two shade-tolerant species (Quercus ilex and Q. pyrenaica), now abundant in the understory, can be predicted to occur soon. The ring-width series of sampled trees and their age and size distributions indicate the different development stages undergone by the forest, which are a reflection of the interaction between the natural dynamics of the vegetation and the different types of human intervention. Finally, the knowledge that a single disturbance episode allows a pine population to establish and persist for at least 150 years may be of interest not only for the Prades mountains, and it may help in the interpretation of most of the present mediterranean landscape of Catalonia.En el presente trabajo se analiza desde el punto de vista de la sucesión ecológica la estructura demográfica, la producción y el vigor de la población de Pinus sylvestris que cubre la parte alta del bosque de Poblet (Montañas de Prades, cordillera prelitoral catalana). La edad de los árboles revela que constituyen una única cohorte que empezó a invadir la zona alrededor del año 1848, hecho que denota la fuerte perturbación a la que debía estar sometido el bosque después de la desamortización (1835). La ausencia de regeneración de P. sylvestris así como su producción y vigor extremadamente bajos sugieren que la población de dicha especie, a pesar de ser la que hoy domina el paisaje, se encuentra en una clara fase de decadencia y puede preverse su próxima sustitución por parte de la ya abundante regeneración de Quercus ilex y Q. pyrenaica, tolerantes a la sombra. A través de las series de crecimientos anuales de los árboles y de las distribuciones de edad y diámetro se ponen de manifiesto las distintas fases de desarrollo por las que ha transcurrido el bosque, condicionadas por la interacción entre la propia dinámica de la vegetación y las diferentes actuaciones del hombre. Finalmente, el hecho de que un único episodio de perturbación haya propiciado el establecimiento y la persistencia de una población de pinos durante 150 años o más es un dato cuyo interés va más allá del estricto entorno de las Montañas de Prades y puede ser útil para interpretar buena parte del paisaje mediterráneo actual de Cataluña

Finite mixture analysis of beauty-contest data using generalised beta distributions

This paper introduces a mixture model based on the beta distribution, without preestablished means and variances, to analyze a large set of Beauty-Contest data obtained from diverse groups of experiments (Bosch-Domenech et al. 2002). This model gives a better t of the experimental data, and more precision to the hypothesis that a large proportion of individuals follow a common pattern of reasoning, described as iterated best reply (degenerate), than mixture models based on the normal distribution. The analysis shows that the means of the distributions across the groups of experiments are pretty stable, while the proportions of choices at dierent levels of reasoning vary across groups.Keywords: Beauty-Contest experiments, decision theory, reasoning hierarchy, finite mixture distribution, beta distribution, EM algorithm.