4,328 research outputs found
What about the toxines analysis? new strategies for sensing applications using the chemistry of diazonium group
Objectives: Typically, the Mouse BioAssay (MBA) is a method widely used in many laboratories for
analysis of marine biotoxins together with chromatographic (UPLC-MS) one [1].
The MBA will be banned from December 2014 by the amending Regulation (EC) Nº
2074/2005 of 10th January 2011. Based on this regulation, new alternative methods
are required for fast detection of biotoxins in aquatic environment and in shellfish
samples. The aim of this research work is to design and to characterize an
electrochemical (bio)sensor for rapid and sensitive detection of biotoxins.Financial support from CRUP (E-136/12)-MICINN- International Projects -
Mobility (PRI-AIBPT-2011-1096) and MEC (CTQ2011-28157
Deformations of canonical triple covers
In this paper, we show that if X is a smooth variety of general type of dimension m≥3 for which the canonical map induces a triple cover onto Y, where Y is a projective bundle over P1 or onto a projective space or onto a quadric hypersurface, embedded by a complete linear series (except Q3 embedded in P4), then the general deformation of the canonical morphism of X is again canonical and induces a triple cover. The extremal case when Y is embedded as a variety of minimal degree is of interest, due to its appearance in numerous situations. For instance, by looking at threefolds Y of minimal degree we find components of the moduli of threefolds X of general type with KX3=3pg−9,KX3≠6, whose general members correspond to canonical triple covers. Our results are especially interesting as well because they have no lower dimensional analogues
How Debian GNU/Linux is translated into Spanish
La Debian GNU/Linux és un dels paquets de programari per a Linux que compta amb una major distribució. Inclou milers de paquets de programari lliure (free, open source) provinents de moltes fonts diferents. Una de les peculiaritats del projecte Debian rau en el fet que funciona gràcies a un grup de voluntaris seleccionats per ells mateixos. En concret, això vol dir que les tasques de localització (inclosa la traducció) a moltes de les llengües previstes es duen a terme a partir de l'esforç de voluntaris. Aquest article descriu com es localitza el Debian al castellà, com a exemple dels esforços que s'estan fent en el món del programari lliure.La Debian GNU/Linux es uno de los paquetes de software para Linux que cuenta con una mayor distribución. Incluye miles de paquetes de software libre (free, open source) que provienen de muchas Fuentes diferentes. Una de las peculiaridades del proyecto Debian radical en el hecho de que funciona gracias a un grupo de voluntarios seleccionados por ellos mismos. En concreto, esto quiere decir que las tareas de localización (incluida la traducción) a muchas de las lenguas previstas se llevan a cabo a partir del esfuerzo de voluntarios. Este artículo describe cómo se localiza el Debian al castellano como ejemplo de los esfuerzos que es están realizando en el mundo del software libre.Debian GNU/Linux is one of the largest Linux-based software distributions, including thousands of libre (free, open source) software packages coming from many different sources. One of the peculiarities of the Debian project is being run altogether by a self-selected group of volunteers. In particular, this means that all the localization tasks (including translation) to the many supported languages is run on volunteer effort. This paper describes how Debian is localized to the Spanish language, as a case example of translation efforts in the libre software world
Deformations of canonical double covers
In this paper we show that if X is a smooth variety of general type of dimension m≥2 for which its canonical map induces a double cover onto Y, where Y is the projective space, a smooth quadric hypersurface or a smooth projective bundle over P1, embedded by a complete linear series, then the general deformation of the canonical morphism of X is again canonical and induces a double cover. The second part of the article proves the non-existence of canonical double structures on the rational varieties above mentioned. Our results have consequences for the moduli of varieties of general type of arbitrary dimension, since they show that infinitely many moduli spaces of higher dimensional varieties of general type have an entire “hyperelliptic” component. This is in sharp contrast with the case of curves or surfaces of lower Kodaira dimension
A new approach to domoic acid detection
The standard method for detection of marine toxins in bivalve is based on a mouse
bioassay that presents several disadvantages such as its cost, non-specificity, time
analysis and of course etic constraints. On the other hand regulation has been modified
by the European Commission 15/2011 on January 10th, 2011, replacing Regulation
(EC) No 2074/2005 and mouse bioassay will be banned from December 31, 2014. The
development of new methods for a rapid screening for detection of toxins is highly
needed. Electrochemical sensors are adequate for the development of user-friendly
analytical methods that could therefore be used in a daily base by fisherman.
In this work, we present a new strategy for the detection of domoic acid (amnesic toxin)
based on the functionalization of carbon screen printed electrodes (SPE) and SPE
modified with carbon nanotubes (CNTs). The functionalization is based in the
immobilization of diazonium ion generated by the 4-nitroaniline diazotization with
sodium nitrite in hydrochloridric acid. Although DA is not electroactive, it can be
detected by means of a redox probe K4(FeCN)6, which electrochemical response
depends on the concentration of DA immobilized on a functionalized SPE. Preliminary
work has shown the possibility to carry out the immobilization without the use of
bifunctional agents, such as carbodiimides, n-hydroxysuccinimide, that facilitates the
bond between -NH2 and -COOH groups simplifying the design of the sensor.
Experimental variables such as pH, temperature and time were optimized. Peak
potential shift and enhancement of current intensity were analyzed
No surviving evolved companions to the progenitor of supernova SN 1006
Type Ia supernovae are thought to occur as a white dwarf made of carbon and
oxygen accretes sufficient mass to trigger a thermonuclear explosion. The
accretion could occur slowly from an unevolved (main-sequence) or evolved
(subgiant or giant) star, that being dubbed the single-degenerate
channel, or rapidly as it breaks up a smaller orbiting white dwarf (the double-
degenerate channel). Obviously, a companion will survive the explosion
only in the single-degenerate channel. Both channels might contribute to
the production of type Ia supernovae but their relative proportions
still remain a fundamental puzzle in astronomy. Previous searches for remnant
companions have revealed one possible case for SN 1572, though that has
been criticized. More recently, observations have restricted surviving
companions to be small, main-sequence stars, ruling out giant
companions, though still allowing the single-degenerate channel. Here we report
the result of a search for surviving companions to the progenitor of SN
1006. None of the stars within 4' of the apparent site of the explosion
is associated with the supernova remnant, so we can firmly exclude all giant
and subgiant companions to the progenitor. Combined with the previous results,
less than 20 per cent of type Iae occur through the single degenerate channel.Comment: Published as a letter in Nature (2012 September 27
Determining the nuclear neutron distribution from Coherent Elastic neutrino-Nucleus Scattering: current results and future prospects
Coherent elastic neutrino-nucleus scattering (CENS), a process recently
measured for the first time at ORNL's Spallation Neutron Source, is directly
sensitive to the weak form factor of the nucleus. The European Spallation
Source (ESS), presently under construction, will generate the most intense
pulsed neutrino flux suitable for the detection of CENS. In this paper we
quantify its potential to determine the root mean square radius of the
point-neutron distribution, for a variety of target nuclei and a suite of
detectors. To put our results in context we also derive, for the first time, a
constraint on this parameter from the analysis of the energy and timing data of
the CsI detector at the COHERENT experiment.Comment: 16 pages, 4 figures. Minor text changes and references added. Matches
version accepted by JHE
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