Biogeografía mundial de la enfermedad de Lyme: favorabilidad ambiental y zoonótica

La borreliosis de Lyme es una enfermedad infecciosa causada por espiroquetas del género Borrelia, transmitida al ser humano por garrapatas del género Ixodes. Es una de las enfermedades más prevalentes en el hemisferio norte que tiene en los mamíferos sus principales reservorios, especialmente en los de pequeño tamaño, como los comprendidos por los órdenes Rodentia, Lagomorpha, y Eulipotyphla. Mediante un análisis biogeográfico se pretende explicar el ensamblaje espacial de esta enfermedad infecciosa por todo el mundo. Utilizando la función de favorabilidad, se presenta un modelo de distribución de la enfermedad de Lyme a partir de datos de presencias mundiales de las zonas endémicas de la enfermedad, basado en una combinación de varios factores capaces de condicionar la incidencia de los casos: 1) condiciones ambientales (clima, topografía y variables antrópicas); 2) estructura espacial (probablemente ligada a la historia de la enfermedad); 3) zonas favorables para la presencia de vectores (garrapatas); y 4) la distribución de todos los pequeños mamíferos que podrían ser potenciales reservorios de la bacteria (representados por sus tipos de distribución o corotipos). El modelo se traduce en un mapa de zonas favorables para la aparición de focos de la enfermedad, y en la ponderación de los factores que afectan a su distribución. Se discuten las zonas o puntos calientes para la aparición de futuras epidemias, y se pone de manifiesto la utilidad del concepto de favorabilidad como base para la prevención de zoonosis de importancia para la salud humana.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Junta de Andalucía, con financiación del Fondo Social Europeo, en el marco del Sistema Nacional de Garantía Juvenil y del Programa Operativo de Empleo Juvenil 2014 – 202

Biogeografía mundial de la fiebre amarilla

La fiebre amarilla es una enfermedad vírica aguda, hemorrágica causada por Flavivirus. Sus vectores en el ciclo urbano, entre personas, son Aedes aegypti y A. albopictus; en el ciclo selvático, zoonótico entre primates y humanos, son los géneros Haemagogus, Sabethes y Aedes. La patogeografía utiliza herramientas y conceptos biogeográficos para comprender la distribución de los patógenos y los factores que condicionan que aparezcan nuevos brotes de enfermedad. El modelado espacial puede generar predicciones sólidas sobre la distribución geográfica de los patógenos y sus reservorios. Aquí se ha pretendido comprender qué determina la aparición de brotes, considerando los patrones de distribución de los grupos animales vinculados a los ciclos zoonóticos de la fiebre amarilla. Se presenta un mapa con la distribución de las áreas favorables para la aparición de casos en humanos, basado en su incidencia durante el siglo XXI. El mapa resulta de la combinación de variables ambientales y antropogénicas que favorecen la presencia del virus; de su tendencia espacial durante las décadas anteriores; de la influencia ejercida por los ciclos selváticos en África y en Suramérica; y de la presencia de condiciones favorables para los vectores. Los ciclos selváticos están influidos, a su vez, por la presencia de ciertos patrones de distribución (corotipos) mostrados por los primates. Olivero et al. (2017) demostraron por primera vez que los patrones de distribución de los mamíferos contribuyen a explicar la distribución de un virus. La biodiversidad de mamíferos podría ser el factor de predicción más fuerte que explica las similitudes entre las regiones patogeográficas del mundo. Este estudio brinda herramientas metodológicas que pueden ser aplicables a distintas enfermedades, especialmente a aquellas que combinan ciclos zoonóticos y antroponóticos; y muestra áreas favorables a la aparición de fiebre amarilla incluso donde ésta no ha sido registrada.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. El presente trabajo ha sido financiado por el proyecto CGL2016-76747-R del Ministerio de Economía, Industria y Competitividad y Fondos FEDER

A gravitational-wave standard siren measurement of the Hubble constant

On 17 August 2017, the Advanced LIGO 1 and Virgo 2 detectors observed the gravitational-wave event GW170817-a strong signal from the merger of a binary neutron-star system 3 . Less than two seconds after the merger, a γ-ray burst (GRB 170817A) was detected within a region of the sky consistent with the LIGO-Virgo-derived location of the gravitational-wave source 4-6 . This sky region was subsequently observed by optical astronomy facilities 7 , resulting in the identification 8-13 of an optical transient signal within about ten arcseconds of the galaxy NGC 4993. This detection of GW170817 in both gravitational waves and electromagnetic waves represents the first 'multi-messenger' astronomical observation. Such observations enable GW170817 to be used as a 'standard siren' 14-18 (meaning that the absolute distance to the source can be determined directly from the gravitational-wave measurements) to measure the Hubble constant. This quantity represents the local expansion rate of the Universe, sets the overall scale of the Universe and is of fundamental importance to cosmology. Here we report a measurement of the Hubble constant that combines the distance to the source inferred purely from the gravitational-wave signal with the recession velocity inferred from measurements of the redshift using the electromagnetic data. In contrast to previous measurements, ours does not require the use of a cosmic 'distance ladder' 19 : the gravitational-wave analysis can be used to estimate the luminosity distance out to cosmological scales directly, without the use of intermediate astronomical distance measurements. We determine the Hubble constant to be about 70 kilometres per second per megaparsec. This value is consistent with existing measurements 20,21 , while being completely independent of them. Additional standard siren measurements from future gravitationalwave sources will enable the Hubble constant to be constrained to high precision

Search for Tensor, Vector, and Scalar Polarizations in the Stochastic Gravitational-Wave Background

The detection of gravitational waves with Advanced LIGO and Advanced Virgo has enabled novel tests of general relativity, including direct study of the polarization of gravitational waves. While general relativity allows for only two tensor gravitational-wave polarizations, general metric theories can additionally predict two vector and two scalar polarizations. The polarization of gravitational waves is encoded in the spectral shape of the stochastic gravitational-wave background, formed by the superposition of cosmological and individually unresolved astrophysical sources. Using data recorded by Advanced LIGO during its first observing run, we search for a stochastic background of generically polarized gravitational waves. We find no evidence for a background of any polarization, and place the first direct bounds on the contributions of vector and scalar polarizations to the stochastic background. Under log-uniform priors for the energy in each polarization, we limit the energy densities of tensor, vector, and scalar modes at 95% credibility to Ω0T<5.58×10-8, Ω0V<6.35×10-8, and Ω0S<1.08×10-7 at a reference frequency f0=25 Hz. © 2018 American Physical Society

Global urban environmental change drives adaptation in white clover

Urbanization transforms environments in ways that alter biological evolution. We examined whether urban environmental change drives parallel evolution by sampling 110,019 white clover plants from 6169 populations in 160 cities globally. Plants were assayed for a Mendelian antiherbivore defense that also affects tolerance to abiotic stressors. Urban-rural gradients were associated with the evolution of clines in defense in 47% of cities throughout the world. Variation in the strength of clines was explained by environmental changes in drought stress and vegetation cover that varied among cities. Sequencing 2074 genomes from 26 cities revealed that the evolution of urban-rural clines was best explained by adaptive evolution, but the degree of parallel adaptation varied among cities. Our results demonstrate that urbanization leads to adaptation at a global scale

On the progenitor of binary neutron star merger GW170817

On 2017 August 17 the merger of two compact objects with masses consistent with two neutron stars was discovered through gravitational-wave (GW170817), gamma-ray (GRB 170817A), and optical (SSS17a/AT 2017gfo) observations. The optical source was associated with the early-type galaxy NGC 4993 at a distance of just ∼40 Mpc, consistent with the gravitational-wave measurement, and the merger was localized to be at a projected distance of ∼2 kpc away from the galaxy's center. We use this minimal set of facts and the mass posteriors of the two neutron stars to derive the first constraints on the progenitor of GW170817 at the time of the second supernova (SN). We generate simulated progenitor populations and follow the three-dimensional kinematic evolution from binary neutron star (BNS) birth to the merger time, accounting for pre-SN galactic motion, for considerably different input distributions of the progenitor mass, pre-SN semimajor axis, and SN-kick velocity. Though not considerably tight, we find these constraints to be comparable to those for Galactic BNS progenitors. The derived constraints are very strongly influenced by the requirement of keeping the binary bound after the second SN and having the merger occur relatively close to the center of the galaxy. These constraints are insensitive to the galaxy's star formation history, provided the stellar populations are older than 1 Gyr

First Search for Gravitational Waves from Known Pulsars with Advanced LIGO

We present the result of searches for gravitational waves from 200 pulsars using data from the first observing run of the Advanced LIGO detectors. We find no significant evidence for a gravitational-wave signal from any of these pulsars, but we are able to set the most constraining upper limits yet on their gravitational-wave amplitudes and ellipticities. For eight of these pulsars, our upper limits give bounds that are improvements over the indirect spin-down limit values. For another 32, we are within a factor of 10 of the spin-down limit, and it is likely that some of these will be reachable in future runs of the advanced detector. Taken as a whole, these new results improve on previous limits by more than a factor of two

GW170104: Observation of a 50-Solar-Mass Binary Black Hole Coalescence at Redshift 0.2

We describe the observation of GW170104, a gravitational-wave signal produced by the coalescence of a pair of stellar-mass black holes. The signal was measured on January 4, 2017 at 10∶11:58.6 UTC by the twin advanced detectors of the Laser Interferometer Gravitational-Wave Observatory during their second observing run, with a network signal-to-noise ratio of 13 and a false alarm rate less than 1 in 70 000 years. The inferred component black hole masses are 31. 2 + 8.4 − 6.0 M ⊙ and 19. 4 + 5.3 − 5.9 M ⊙ (at the 90% credible level). The black hole spins are best constrained through measurement of the effective inspiral spin parameter, a mass-weighted combination of the spin components perpendicular to the orbital plane, χ eff = − 0.1 2 + 0.21 − 0.30 . This result implies that spin configurations with both component spins positively aligned with the orbital angular momentum are disfavored. The source luminosity distance is 88 0 + 450 − 390     Mpc corresponding to a redshift of z = 0.1 8 + 0.08 − 0.07 . We constrain the magnitude of modifications to the gravitational-wave dispersion relation and perform null tests of general relativity. Assuming that gravitons are dispersed in vacuum like massive particles, we bound the graviton mass to m g ≤ 7.7 × 10 − 23     eV / c 2 . In all cases, we find that GW170104 is consistent with general relativity

First low-frequency Einstein@Home all-sky search for continuous gravitational waves in Advanced LIGO data

We report results of a deep all-sky search for periodic gravitational waves from isolated neutron stars in data from the first Advanced LIGO observing run. This search investigates the low frequency range of Advanced LIGO data, between 20 and 100 Hz, much of which was not explored in initial LIGO. The search was made possible by the computing power provided by the volunteers of the Einstein@Home project. We find no significant signal candidate and set the most stringent upper limits to date on the amplitude of gravitational wave signals from the target population, corresponding to a sensitivity depth of 48.7 [1/root Hz]. At the frequency of best strain sensitivity, near 100 Hz, we set 90% confidence upper limits of 1.8 x 10(-25). At the low end of our frequency range, 20 Hz, we achieve upper limits of 3.9 x 10(-24). At 55 Hz we can exclude sources with ellipticities greater than 10(-5) within 100 pc of Earth with fiducial value of the principal moment of inertia of 10(38) kg m(2)