Exact solutions in two-dimensional string cosmology with back reaction

We present analytic cosmological solutions in a model of two-dimensional dilaton gravity with back reaction. One of these solutions exhibits a graceful exit from the inflationary to the FRW phase and is nonsingular everywhere. A duality related second solution is found to exist only in the ``pre-big-bang'' epoch and is singular at $\tau = 0$. In either case back reaction is shown to play a crucial role in determining the specific nature of these geometries.Comment: Shortened slightly, references added, to appear in Physical Review D (Rapid Communications). 16 pages, RevTex, 3 PostScript figure

Casorati Determinant Form of Dark Soliton Solutions of the Discrete Nonlinear Schr\"odinger Equation

It is shown that the $N$-dark soliton solutions of the integrable discrete nonlinear Schr\"odinger (IDNLS) equation are given in terms of the Casorati determinant. The conditions for reduction, complex conjugacy and regularity for the Casorati determinant solution are also given explicitly. The relationship between the IDNLS and the relativistic Toda lattice is discussed.Comment: First version was uploaded in 23 Jun 2005. Published in Journal of the Physical Society of Japan in May, 200

Coupled climate response to Atlantic Multidecadal Variability in a multi-model multi-resolution ensemble

North Atlantic sea surface temperatures (SSTs) underwent pronounced multidecadal variability during the twentieth and early twenty-first century. We examine the impacts of this Atlantic Multidecadal Variability (AMV), also referred to as the Atlantic Multidecadal Oscillation (AMO), on climate in an ensemble of five coupled climate models at both low and high spatial resolution. We use a SST nudging scheme specified by the Coupled Model Intercomparision Project’s Decadal Climate Prediction Project Component C (CMIP6 DCPP-C) to impose a persistent positive/negative phase of the AMV in the North Atlantic in coupled model simulations; SSTs are free to evolve outside this region. The large-scale seasonal mean response to the positive AMV involves widespread warming over Eurasia and the Americas, with a pattern of cooling over the Pacific Ocean similar to the Pacific Decadal Oscillation (PDO), together with a northward displacement of the inter-tropical convergence zone (ITCZ). The accompanying changes in global atmospheric circulation lead to widespread changes in precipitation. We use Analysis of Variance (ANOVA) to demonstrate that this large-scale climate response is accompanied by significant differences between models in how they respond to the common AMV forcing, particularly in the tropics. These differences may arise from variations in North Atlantic air-sea heat fluxes between models despite a common North Atlantic SST forcing pattern. We cannot detect a widespread effect of increased model horizontal resolution in this climate response, with the exception of the ITCZ, which shifts further northwards in the positive phase of the AMV in the higher resolution configuratio

Nanoinformatics: developing new computing applications for nanomedicine

Nanoinformatics has recently emerged to address the need of computing applications at the nano level. In this regard, the authors have participated in various initiatives to identify its concepts, foundations and challenges. While nanomaterials open up the possibility for developing new devices in many industrial and scientific areas, they also offer breakthrough perspectives for the prevention, diagnosis and treatment of diseases. In this paper, we analyze the different aspects of nanoinformatics and suggest five research topics to help catalyze new research and development in the area, particularly focused on nanomedicine. We also encompass the use of informatics to further the biological and clinical applications of basic research in nanoscience and nanotechnology, and the related concept of an extended ?nanotype? to coalesce information related to nanoparticles. We suggest how nanoinformatics could accelerate developments in nanomedicine, similarly to what happened with the Human Genome and other -omics projects, on issues like exchanging modeling and simulation methods and tools, linking toxicity information to clinical and personal databases or developing new approaches for scientific ontologies, among many others

Human bocavirus infections in Spanish 0-14 year-old: clinical and epidemiological characteristics of an emerging respiratory virus

[ES] Introducción: En el año 2005 se ha clonado un nuevo virus respiratorio, llamado bocavirus humano (HBoV) de muestras respiratorias procedentes de lactantes y niños suecos con infección respiratoria de vías bajas. Objetivos: Determinar si HBoV ha circulado en España, estimar la frecuencia de infecciones por HBoV en los niños hospitalizados por infección respiratoria y describir sus características clínicas y epidemiológicas. Pacientes y métodos: Estudio descriptivo, prospectivo de las infecciones confirmadas por HBoV en niños menores de 14 años, hospitalizados por infección respiratoria desde octubre de 2004 a junio de 2005. Para el diagnóstico virológico se realizó reacción en cadena de la polimerasa-transcripción inversa (RT-PCR) múltiple para virus respiratorio sincitial (VRS) A y B, influenza A, B y C, parainfluenza 1-4, adenovirus y rinovirus; PCR para metapneumovirus humano (hMPV) y PCR para HBoV en aspirado nasofaríngeo. Se describen las características clínicas y epidemiológicas de los pacientes. Resultados: Se detectaron 52 casos de infección por HBoV, lo que supuso el 17,1 % (IC [intervalo de confianza] 95 %: 13 a 21) de los pacientes hospitalizados por procesos respiratorios. HBoV fue el tercer agente viral tras el VRS (30 %) y el rinovirus (25 %). En 39 casos (71,1 %) se detectó coinfección con otro virus respiratorio. El 50 % de los pacientes eran menores de 13,6 meses y el 75% menores de 2 años. Los diagnósticos más frecuentes fueron sibilancias recurrentes (55,8 %), bronquiolitis (21,2 %) y neumonía (15,4 %). Dos niños presentaron sepsis clínica con exantema petequial. El 71,2 % presentó fiebre superior a 38 °C e infiltrado radiológico el 44 %. Presentaron hipoxia el 55,8 % de los niños. Dos pacientes presentaron aislamientos positivos para HBoV en distintos episodios. Las coinfecciones fueron similares a las infecciones simples, excepto que presentaron hipoxia con más frecuencia, p = 0,038. Conclusiones: HBoV es uno de los virus más frecuentes en las infecciones respiratorias graves de los niños, sólo precedido por VRS y rinovirus. Las coinfecciones son muy frecuentes. La mayoría de los niños son lactantes con sibilancias recurrentes y bronquiolitis. [EN] Introduction: In 2005 a new respiratory virus, called human bocavirus (HBoV), was cloned from respiratory samples from Swedish infants and children with lower respiratory tract infections. Objectives: To determine whether HBoV has circulated in Spain, estimate the frequency of HBoV infections in patients hospitalized for respiratory infection and describe the clinical and epidemiological characteristics of these patients. Patients and methods: We performed a descriptive prospective study of confirmed HBoV infections in patients aged 38 degrees C was found in 72.1% and radiological infiltrate in 44%. Hypoxia was present in 55.8 % of the patients. HBoV was isolated in distinct episodes in two patients. Coinfections were similar to simple infections except that hypoxia was more frequent in the former (p = 0.038). Conclusions: HBoV is one of the most frequent viruses in severe respiratory infections in patients aged less than 14 years old. Only RSV and rhinovirus are more frequent. Coinfections are highly frequent. Most patients are infants with recurrent wheezing and bronchiolitis.Estudio parcialmente financiado por el Fondo de Investigaciones Sanitarias. FIS N.º 98/0310.S

The Antares Collaboration : Contributions to the 34th International Cosmic Ray Conference (ICRC 2015, The Hague)

The ANTARES detector, completed in 2008, is the largest neutrino telescope in the Northern hemisphere. Located at a depth of 2.5 km in the Mediterranean Sea, 40 km off the Toulon shore, its main goal is the search for astrophysical high energy neutrinos. In this paper we collect the 21 contributions of the ANTARES collaboration to the 34th International Cosmic Ray Conference (ICRC 2015). The scientific output is very rich and the contributions included in these proceedings cover the main physics results, ranging from steady point sources, diffuse searches, multi-messenger analyses to exotic physics

The Pioneer anomaly in the context of the braneworld scenario

We examine the Pioneer anomaly - a reported anomalous acceleration affecting the Pioneer 10/11, Galileo and Ulysses spacecrafts - in the context of a braneworld scenario. We show that effects due to the radion field cannot account for the anomaly, but that a scalar field with an appropriate potential is able to explain the phenomena. Implications and features of our solution are analyzed.Comment: Final version to appear at Classical & Quantum Gravity. Plainlatex 19 page

Search for muon-neutrino emission from GeV and TeV gamma-ray flaring blazars using five years of data of the ANTARES telescope

The ANTARES telescope is well-suited for detecting astrophysical transient neutrino sources as it can observe a full hemisphere of the sky at all times with a high duty cycle. The background due to atmospheric particles can be drastically reduced, and the point-source sensitivity improved, by selecting a narrow time window around possible neutrino production periods. Blazars, being radio-loud active galactic nuclei with their jets pointing almost directly towards the observer, are particularly attractive potential neutrino point sources, since they are among the most likely sources of the very high-energy cosmic rays. Neutrinos and gamma rays may be produced in hadronic interactions with the surrounding medium. Moreover, blazars generally show high time variability in their light curves at different wavelengths and on various time scales. This paper presents a time-dependent analysis applied to a selection of flaring gamma-ray blazars observed by the FERMI/LAT experiment and by TeV Cherenkov telescopes using five years of ANTARES data taken from 2008 to 2012. The results are compatible with fluctuations of the background. Upper limits on the neutrino fluence have been produced and compared to the measured gamma-ray spectral energy distribution.Comment: 27 pages, 16 figure

Whitepaper: Understanding land-atmosphere interactions through tower-based flux and continuous atmospheric boundary layer measurements

Executive summary ● Target audience: AmeriFlux community, AmeriFlux Science Steering Committee & Department of Energy (DOE) program managers [ARM/ASR (atmosphere), TES (surface), and SBR (subsurface)] ● Problem statement: The atmospheric boundary layer mediates the exchange of energy and matter between the land surface and the free troposphere integrating a range of physical, chemical, and biological processes. However, continuous atmospheric boundary layer observations at AmeriFlux sites are still scarce. How can adding measurements of the atmospheric boundary layer enhance the scientific value of the AmeriFlux network? ● Research opportunities: We highlight four key opportunities to integrate tower-based flux measurements with continuous, long-term atmospheric boundary layer measurements: (1) to interpret surface flux and atmospheric boundary layer exchange dynamics at flux tower sites, (2) to support regionalscale modeling and upscaling of surface fluxes to continental scales, (3) to validate land-atmosphere coupling in Earth system models, and (4) to support flux footprint modelling, the interpretation of surface fluxes in heterogeneous terrain, and quality control of eddy covariance flux measurements. ● Recommended actions: Adding a suite of atmospheric boundary layer measurements to eddy covariance flux tower sites would allow the Earth science community to address new emerging research questions, to better interpret ongoing flux tower measurements, and would present novel opportunities for collaboration between AmeriFlux scientists and atmospheric and remote sensing scientists. We therefore recommend that (1) a set of instrumentation for continuous atmospheric boundary layer observations be added to a subset of AmeriFlux sites spanning a range of ecosystem types and climate zones, that (2) funding agencies (e.g., Department of Energy, NASA) solicit research on land-atmosphere processes where the benefits of fully integrated atmospheric boundary layer observations can add value to key scientific questions, and that (3) the AmeriFlux Management Project acquires loaner instrumentation for atmospheric boundary layer observations for use in experiments and short-term duration campaigns

Singularity free dilaton-driven cosmologies and pre-little-bang

There are no reasons why the singularity in the growth of the dilaton coupling should not be regularised, in a string cosmological context, by the presence of classical inhomogeneities. We discuss a class of inhomogeneous dilaton-driven models whose curvature invariants are all bounded and regular in time and space. We prove that the non-space-like geodesics of these models are all complete in the sense that none of them reaches infinity for a finite value of the affine parameter. We conclude that our examples represent truly singularity-free solutions of the low energy beta functions. We discuss some symmetries of the obtained solutions and we clarify their physical interpretation. We also give examples of solutions with spherical symmetry. In our scenario each physical quantity is everywhere defined in time and space, the big-bang singularity is replaced by a maximal curvature phase where the dilaton kinetic energy reaches its maximum. The maximal curvature is always smaller than one (in string units) and the coupling constant is also smaller than one and it grows between two regimes of constant dilaton, implying, together with the symmetries of the solutions, that higher genus and higher curvature corrections are negligible. We argue that our examples describe, in a string cosmological context, the occurrence of ``little bangs''(i.e. high curvature phases which never develop physical singularities). They also suggest the possibility of an unexplored ``pre-little-bang'' phase.Comment: 25 pages in LaTex style, 3 encapsulated figure