Einstein constraints on a characteristic cone

We analyse the Cauchy problem on a characteristic cone, including its vertex, for the Einstein equations in arbitrary dimensions. We use a wave map gauge, solve the obtained constraints and show gauge conservation.Comment: 10 pages, to be published in the Proceedings of the 15th International Conference on Waves and Stability in Continuous Media, held in Palermo, 28th June to 1st July 200

Conformational Control of Tetrahydropyran-based Hybrid Dipeptide Catalysts Improves Activity and Stereoselectivity

© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Herein, we introduce and demonstrate how carbohydrates can be used as conformational control units of organocatalysts to tune their catalytic properties. New hybrid dipeptide-like organocatalysts based on ζ-sugar aminoacids and proline were prepared and tested for the asymmetric Michael addition of aldehydes to β-nitrostyrenes. Taking full advantage of the modular nature of the carbohydrate motif, both reactivity and stereoselectivity were significantly improved. By simple structural changes, such as the elimination of the methoxy group in the C4 position of the tetrahydropyran ring, we obtained two complementary catalysts that allow access to both enantiomers of the γ-nitroaldehydes with excellent yields, diastereoselectivity, and enantiomeric excesses between 97 and 99%, using a catalytic load even below 1 mol%

Local Behavior of the First-Order Gradient Correction to the Thomas-Fermi Kinetic Energy Functional

The first order gradient correction to the Thomas-Fermi functional, proposed by Haq, Chattaraj and Deb (Chem. Phys. Lett. vol. 81, 8031, 1984) has been studied by evaluating both the total kinetic energy and the local kinetic energy density. For testing the kinetic energy density we evaluate its deviation from an exact result through a quality factor, a parameter that reflects the quality of the functionals in a better way than their relative errors. The study is performed on two different systems: light atoms (up to Z=18) and a noninteracting model of fermions confined in a Coulombic-type potential. It is found than this approximation gives very low relative errors and a better local behavior than any of the usual generalized gradient approximation semilocal kinetic density functionals.Comment: 7 pages, 2 tables, 4 figure

Philopatry and natal dispersal of Montagu's harriers (Circus pygargus) breeding in Spain: a review of existing data

et al.Natal dispersal is an important component of bird ecology, plays a key role in many ecological and evolutionary processes, and has important conservation implications. Nevertheless, detailed knowledge on natal dispersal is still lacking in many bird species, especially raptors. We review and compile existing information from five tagging programmes of juvenile Montagu's harriers (Circus pygargus) in different Spanish regions, with PVC rings or wing tags, to provide an assessment of philopatry and natal dispersal of the species in Spain. Only 7% of all tagged harriers were observed as breeders in subsequent years. The percentage of philopatric (i. e. breeding within 10 km of the natal site) males and females was lower that 5%. Overall, there were no sexual differences in percentage of philopatric birds or dispersal distances, but we found study area differences. The low philopatry observed suggests a high capacity for natal dispersal in this species, for both sexes, and therefore high genetic mixing between populations. Differences in philopatry between study areas may be influenced by the different observation effort or detectability, or else reflect different philopatric strategies among populations. Finally, we found no significant differences in philopatry rate or dispersal distances related to tagging method, suggesting that tagging technique has a smaller effect than monitoring effort or observation ease on observation probability. Developing tagging programmes at a small scale and without procuring very large-scale and intensive subsequent monitoring is not worthwhile for evaluating philopatry and natal dispersal in this species.We are grateful to the Servicio de Biodiversidad from Conselleria de Medio Ambiente, Agua, Urbanismo y Vivienda (Generalitat Valenciana) for providing data from the Castellón area. In Tarifa, the population study was funded by Fundación Migres through a collaboration project with the Asociación Eólica de Tarifa, and theringing programme was carried out by Milvus-GOES and Cigüeña Negra ringing groups. R. L. has a postdoctoral grant (reference 10/12-C) co-funded by the Consejería de Educación y Ciencia (Junta de Comunidades de Castilla-La Mancha) and the European Social Fund.Peer Reviewe

Integrated landscape initiatives in Europe: Multi-sector collaboration in multi-functional landscapes

Landscapes are linked to human well-being in a multitude of ways, some of which are challenged by global market forces and traditional management approaches. In response to this situation there has been a rise in local initiatives to sustain the values of landscape. The aim of this paper is to provide a systematic analysis of the spectrum of these initiatives in Europe in terms of patterns of organisation, participants, resources, problems, and landscape values addressed. This review collects examples of integrated landscape initiatives from all over Europe through systematic internet key word searches and canvassing of European umbrella organisations; followed by an online survey of representatives from the identified initiatives (n = 71). Our results show that the most relevant characteristics of integrated landscape initiatives in Europe are: a holistic approach to landscape management (acting in multifunctional landscapes and combining different objectives), the involvement and coordination of different sectors and stakeholders at many levels, and the role as agents of awareness raising and learning hubs. Integrated landscape initiatives mainly depend on impulses of local civil society. Identified barriers to their work include a lack of funding and institutional support. Therefore, political and societal action is needed to increase their effectiveness

On The spectrum of a Noncommutative Formulation of the D=11 Supermembrane with Winding

A regularized model of the double compactified D=11 supermembrane with nontrivial winding in terms of SU(N) valued maps is obtained. The condition of nontrivial winding is described in terms of a nontrivial line bundle introduced in the formulation of the compactified supermembrane. The multivalued geometrical objects of the model related to the nontrivial wrapping are described in terms of a SU(N) geometrical object which in the $N\to \infty$ limit, converges to the symplectic connection related to the area preserving diffeomorphisms of the recently obtained non-commutative description of the compactified D=11 supermembrane.(I. Martin, J.Ovalle, A. Restuccia. 2000,2001) The SU(N) regularized canonical lagrangian is explicitly obtained. In the $N\to \infty$ limit it converges to the lagrangian in (I.Martin, J.Ovalle, A.Restuccia. 2000,2001) subject to the nontrivial winding condition. The spectrum of the hamiltonian of the double compactified D=11 supermembrane is discussed. Generically, it contains local string like spikes with zero energy. However the sector of the theory corresponding to a principle bundle characterized by the winding number $n \neq 0$, described by the SU(N) model we propose, is shown to have no local string-like spikes and hence the spectrum of this sector should be discrete.Comment: 16 pages.Latex2

Detección de ADN de pescado en piensos vegetales mediante una técnica de PCR en tiempo real

A quantitative polymerase chain reaction (PCR) assay using SYBR green detection system has been developed for detection of fishmeal in feedstuffs. The real-time PCR method combines the use of fish-specific primers that amplify a 87 bp fragment of the mitochondrial 12S ribosomal RNA gene from fish species, and universal primers that amplify a 99 bp fragment of the nuclear 18S ribosomal RNA gene from eukaryotic DNA. The PCR method developed was applied to fish tissues/oats binary mixtures demonstrating its suitability for the detection of fish DNA in mixtures containing as low as 0.1% of fish tissues.Se ha desarrollado una técnica de PCR en tiempo real, utilizando el agente intercalador fluorescente SYBR® Green, para la detección cuantitativa de la presencia de harinas de pescado en piensos. El método combina el uso de cebadores específicos de pescado que amplifican un fragmento de 87 pb del gen mitocondrial ARNr 12S, junto a cebadores universales que amplifican un fragmento conservado de 99 pb del gen nuclear ARNr 18S en el ADN de los organismos eucariotas. La técnica desarrollada permitió detectar y cuantificar hasta un 0,1% de ADN de pescado en mezclas experimentales de pescado/avena

Polymerase chain reaction detection of rabbit DNA in food and animal feed

[EN] A polymerase chain reaction (PCR) based on oligonucleotide primers targeting the mitochondrial 12S rRNA gene was developed for the specific identification of rabbit DNA (Oryctolagus cuniculus) in food and feedstuffs. The specificity of the primers was verified by PCR analysis of DNA from 32 non-target species including mammals, birds, fish, and plant species. Analysis of experimental mixtures demonstrated the presence of rabbit-derived materials in the range of 0.1-100%. Prolonged heat treatment (up to 133ºC for 20 min at 300 kPa) applied to rabbit muscle/oats binary mixtures did not affect the performance of the method, which could therefore be said to be very useful for the accurate identification of rabbit materials in products submitted to denaturing technologies when other methods are not suitable.This study was supported by Grant Nº. AGL 2007-60077 from the Spanish Ministerio de Educación y Ciencia and the Programa de Vigilancia Sanitaria S-0505/AGR/000265 of the Comunidad de Madrid (Spain). Irene Martín is the recipient of a fellowship from the Universidad Complutense de Madrid (Spain). Violeta Fajardo and María Rojas are recipients of fellowships from the Ministerio de Educación y Ciencia (Spain).Martín, I.; García, T.; Fajardo, V.; Rojas, M.; Pegels, N.; Hernández, P.; González, I.... (2009). Polymerase chain reaction detection of rabbit DNA in food and animal feed. World Rabbit Science. 17(1):27-34. doi:10.4995/wrs.2009.667273417

Variaciones estacionales en las preferencias de hábitat de la ganga ibérica en estepas agrícolas

[EN]: We investigated habitat use and preferences of pin-tailed sandgrouse Pterocles alchata in agrarian pseudo-steppes of central Spain. We used radio-tracking to characterise habitat selection throughout the year and look for seasonal variations. Pin-tailed sandgrouses selected ploughed fields all year round, except in winter when they preferred stubble fields. Pasturelands were used more often than expected in the breeding and post-breeding seasons and fallows in winter and pre-breeding seasons. Cereal crops, olive groves and vineyards were avoided. Our results indicate that appropriate habitat management for the pin-tailed sandgrouse should take into consideration its habitat preferences during the full annual cycle.[ES]: Estudiamos el uso y las preferencias de hábitat de la ganga ibérica Pterocles alchata en el centro de España. Mediante radio-seguimiento caracterizamos el uso y selección de hábitat a lo largo de un ciclo anual, e investigamos las variaciones estacionales. Las gangas seleccionaron campos labrados durante todo el año, excepto en invierno, cuando prefirieren los rastrojos. Los pastos fueron seleccionados positivamente en la estación de cría y en la post-reproductiva, y los barbechos en la invernal y pre-reproductiva. Las siembras de cereal, olivares y viñedos fueron evitados. Un correcto manejo del hábitat de la ganga ibérica debería tener en cuenta sus preferencias de hábitat durante el ciclo anual completo.The study was financed by the Dirección General de Investigación (projects CGL2007-66322/BOS and CGL2008-04282/BOS), and the Consejería de Educación y Ciencia of Castilla-La Mancha (projects PAI08-0171-9582 and PAC06-137). The Consejería de Medio Ambiente y Desarrollo Rural of the Junta of Castilla-La Mancha allowed us to capture and radio-tag the birds. C. A. Martín holds a postdoctoral contract (I3P Programme, CSIC), and F. Casas was supported by a postdoctoral grant of the Junta de Comunidades de Castilla-La Mancha (JCCM).Peer Reviewe