1,166 research outputs found

    The very faint hard state of the persistent neutron star X-ray binary SLX 1737-282 near the Galactic centre

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    We report on a detailed study of the spectral and temporal properties of the neutron star low mass X-ray binary SLX 1737-282, which is located only ~1degr away from Sgr A. The system is expected to have a short orbital period, even within the ultra-compact regime, given its persistent nature at low X-ray luminosities and the long duration thermonuclear burst that it has displayed. We have analysed a Suzaku (18 ks) observation and an XMM-Newton (39 ks) observation taken 7 years apart. We infer (0.5-10 keV) X-ray luminosities in the range 3-6 x10^35erg s-1, in agreement with previous findings. The spectra are well described by a relatively cool (kTbb = 0.5 keV) black body component plus a Comptonized emission component with {\Gamma} ~1.5-1.7. These values are consistent with the source being in a faint hard state, as confirmed by the ~ 20 per cent fractional root mean square amplitude of the fast variability (0.1 - 7 Hz) inferred from the XMM-Newton data. The electron temperature of the corona is >7 keV for the Suzaku observation, but it is measured to be as low as ~2 keV in the XMM-Newton data at higher flux. The latter is significantly lower than expected for systems in the hard state. We searched for X-ray pulsations and imposed an upper limit to their semi-amplitude of 2 per cent (0.001 - 7 Hz). Finally, we investigated the origin of the low frequency variability emission present in the XMM-Newton data and ruled out an absorption dip origin. This constraint the orbital inclination of the system to 65 degr unless the orbital period is longer than 11 hr (i.e. the length of the XMM-Newton observation).Comment: 7 pages, 4 figures, 1 table. Accepted for publication in MNRA

    Registry of non-native species in the Two Seas region countries (Great Britain, France, Belgium and the Netherlands)

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    This dataset represents a registry of species that are not native but recorded to live in the wild of at least one of the four countries that comprise the Two Seas Area, i.e. Great Britain, France, Belgium and the Netherlands. For each of the 6,661 species, subspecies and hybrids listed, we provide detailed information on its status in each country, taxonomic affiliation and environment inhabited. The data were collected by review of 36 web- and print-based sources over an eight-month period. Further systematic scanning of three of the most relevant scientific journals, i.e. Neobiota, Aquatic Invasions and BioInvasions Records, recovered 19 additional relevant publications from which information was included in the registry. As a result, the registry will serve as a basis for developing effective, cross-boundary strategies to manage and control non-native species, which can have severe ecological and economic impacts. The registry can further be used as a general reference for both scientists and practitioners, as well as a tool to assess reliability and comprehensiveness of other well-known databases such as the DAISIE portal

    Derivation of the blackfold effective theory

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    We study fluctuations and deformations of black branes over length scales larger than the horizon radius. We prove that the Einstein equations for the perturbed p-brane yield, as constraints, the equations of the effective blackfold theory. We solve the Einstein equations for the perturbed geometry and show that it remains regular on and outside the black brane horizon. This study provides an ab initio derivation of the blackfold effective theory and gives explicit expressions for the metrics near the new black holes and black branes that result from it, to leading order in a derivative expansion.Comment: 20 pages. v4: Typo corrected in eq. (6.11) -- erratum in the published versio

    M2-M5 blackfold funnels

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    We analyze the basic M2-M5 intersection in the supergravity regime using the blackfold approach. This approach allows us to recover the 1/4-BPS self-dual string soliton solution of Howe, Lambert and West as a three-funnel solution of an effective fivebrane worldvolume theory in a new regime, the regime of a large number of M2 and M5 branes. In addition, it allows us to discuss finite temperature effects for non-extremal self-dual string soliton solutions and wormhole solutions interpolating between stacks of M5 and anti-M5 branes. The purpose of this paper is to exhibit these solutions and their basic properties.Comment: 19 pages, 5 figures, harvmac; typo corrected in equation (3.19

    Thermal Giant Gravitons

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    We study the giant graviton solution as the AdS_5 X S^5 background is heated up to finite temperature. The analysis employs the thermal brane probe technique based on the blackfold approach. We focus mainly on the thermal giant graviton corresponding to a thermal D3-brane probe wrapped on an S^3 moving on the S^5 of the background at finite temperature. We find several interesting new effects, including that the thermal giant graviton has a minimal possible value for the angular momentum and correspondingly also a minimal possible radius of the S^3. We compute the free energy of the thermal giant graviton in the low temperature regime, which potentially could be compared to that of a thermal state on the gauge theory side. Moreover, we analyze the space of solutions and stability of the thermal giant graviton and find that, in parallel with the extremal case, there are two available solutions for a given temperature and angular momentum, one stable and one unstable. In order to write down the equations of motion, action and conserved charges for the thermal giant graviton we present a slight generalization of the blackfold formalism for charged black branes. Finally, we also briefly consider the thermal giant graviton moving in the AdS_5 part.Comment: v1: 32 pages + 11 pages appendices, 13 figures, v2: typos fixed in Sec.2 and other misprints, references adde

    Uniqueness and nonuniqueness of the stationary black holes in 5D Einstein-Maxwell and Einstein-Maxwell-dilaton gravity

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    In the present paper we investigate the general problem of uniqueness of the stationary black solutions in 5D Einstein-Maxwell-dilaton gravity with arbitrary dilaton coupling parameter containing the Einstein-Maxwell gravity as a particular case. We formulate and prove uniqueness theorems classifying the stationary black hole solutions in terms of their interval structure, electric and magnetic charges and the magnetic fluxes. The proofs are based on the nonpositivity of the Riemann curvature operator on the space of the potentials which imposes restrictions on the dilaton coupling parameter.Comment: 21 pages, LaTe

    Actitud de los residentes hacia el alojamiento P2P: la perspectiva de los millennials

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    Uno de los fenómenos que con más fuerza está impactando la actividad turística en la actualidad es el intercambio, a gran escala, de plazas de alojamiento entre particulares. Aunque existe una extensa producción científica sobre la actitud de los residentes hacia el turismo, en general existen muy pocas investigaciones relacionadas con la formación de su actitud hacia este tipo de alojamiento y, específicamente, por parte de los millennials. A partir de un modelo de medición de la percepción de los impactos del turismo basado en la teoría del intercambio social se ha efectuado un análisis comparativo entre los millennials y las generaciones de mayor edad, de la actitud de los residentes hacia esta actividad y de la percepción de los impactos que provoca. El análisis se realiza utilizando una muestra de 1088 ciudadanos de Tenerife y 529 de Mallorca. El estudio confirma que el apoyo que recibe esta actividad es mayor por parte de esta generación.One of the phenomena that has made an important incursion into the tourism activity today is the exchange of accommodation in private homes. Although there is an extensive scientific work on the attitude of residents towards tourism, in general there is very little research related to the formation of their attitude towards this type of accommodation and, specifically, on the part of the millennials. The study has been based on a model of measurement of the perception of the impacts of tourism by using the theory of social exchange. A comparative analysis has been carried out between the millennials and the older generations, the residents’ attitude to this activity and the perception of the impacts that it causes. The analysis is performed by using a sample of 1088 citizens from Tenerife and 529 from Mallorca. The study confirms that the support received for this activity is greater in this generation

    Proline-Rich Peptides with Improved Antimicrobial Activity against E. coli, K. Pneumoniae, and A. Baumannii.

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    Proline-rich antimicrobial peptides (PrAMPs) are promising agents to combat multi-drug resistant pathogens due to a high antimicrobial activity, yet low cytotoxicity. A library of derivatives of the PrAMP Bac5(1-17) was synthesized and screened to identify which residues are relevant for its activity. In this way, we discovered that two central motifs -PIRXP- cannot be modified, while residues at N- and C- termini tolerated some variations. We found five Bac5(1-17) derivatives bearing 1-5 substitutions, with an increased number of arginine and/or tryptophan residues, exhibiting improved antimicrobial activity and broader spectrum of activity while retaining low cytotoxicity toward eukaryotic cells. Transcription/translation and bacterial membrane permeabilization assays showed that these new derivatives still retained the ability to strongly inhibit bacterial protein synthesis, but also acquired permeabilizing activity to different degrees. These new Bac5(1-17) derivatives therefore show a dual mode of action which could hinder the selection of bacterial resistance against these molecules

    Modélisation avec STICS des effets de non travail versus travail du sol en systèmes de culture sous des conditions pédoclimatiques contrastées

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    STICS a été largement utilisé dans de nombreux contextes agro-environnementaux, en particulier en France. Il a été testé en situation labourée et climat tempéré a contrario des systèmes de non-labour en zones tropicales. Quelques études ont évalué STICS dans des conditions tropicales, mais elles sont basées sur d'anciennes versions du modèle où les processus biologiques de dégradation du mulch de résidus de culture ne sont pas décrits. Nos hypothèses sont : i) les bilans d'eau, d'azote et de carbone à court, moyen ou long terme sont davantage sensibles aux modalités de décomposition du mulch qu'à la structure du sol, quand on compare les impacts du non travail du sol et du labour ; ii) le comportement et le devenir du mulch dépendent fortement des interactions advenant au sein du système techno-pédo- climatique. Notre stratégie a été de tester la capacité de STICS (v8.3.1) à simuler les systèmes de culture basés sur le non-labour et avec une couverture permanente d'un paillis de résidus de plantes sous les climats contrastés de plusieurs sites expérimentaux

    Inverse Scattering Construction of a Dipole Black Ring

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    Using the inverse scattering method in six dimensions we construct the dipole black ring of five dimensional Einstein-Maxwell-dilaton theory with dilaton coupling a = 2(2/3)^(1/2).The 5d theory can be thought of as the NS sector of low energy string theory in Einstein frame. It can also be obtained by dimensionally reducing six-dimensional vacuum gravity on a circle. Our new approach uses GL(4, R) integrability structure of the theory inherited from six-dimensional vacuum gravity. Our approach is also general enough to potentially generate dipole black objects carrying multiple rotations as well as more exotic multi-horizon configurations
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