Early recognition by Ball and Hooker in 1878 of plant back-colonization (boomerang) events from Macaronesia to Africa

Recent work in island biogeography has shown that back-colonization (‘boomerang’ events) from islands to continents have occurred more frequently than previously understoodWe report possibly the earliest inference of this pattern, by John Ball and Joseph Dalton Hooker in a book published in 1878

UPDATED STANDARDIZED CATCH RATES OF SWORDFISH (Xiphias gladius) CAUGHT BY THE SPANISH SURFACE LONGLINE FLEET IN THE INDIAN OCEAN DURING THE 2001-2015 PERIOD

Standardized catch rates of the Spanish surface longline fleet targeting swordfish are provided for the period 2001-2015. Generalized Linear Models (GLM) log-normal were used to update standardized catch rates in number of fish and in weight. Factors such as year, area, quarter, gear and bait, as well as the fishing strategy (based on the ratio between the most prevalent species and that appreciated most by skippers) and the interaction quarter*area were taken into account. The models explained 56% and 58% of CPUE variability in number and weight, respectively

STANDARDIZED CATCH RATES IN BIOMASS FOR THE BLUE SHARK (PRIONACE GLAUCA) CAUGHT BY THE SPANISH SURFACE LONGLINE FLEET IN THE INDIAN OCEAN DURING THE 2001-2015 PERIOD

Based on 2,049 trips by vessels in the Spanish surface longline fleet in the Indian Ocean during the period 2001-2015, standardised CPUE catch rates were obtained for the blue shark (Prionace glauca) using General Linear Modelling. The main factors considered were year, quarter, area, ratio, gear and the interaction quarter*area. The basic significant model obtained explained 81% of CPUE variability observed and suggests a stable trend for this blue shark stock in the Indian Ocean. Most of the variability in CPUE was explained by the targeting factor, as represented by the ratio between catch levels for the two most valued and prevalent species landed: swordfish and blue shark. Other significant factors were identified but these were less important. The MIXED model used to analyse sensitivity showed the same trend as that obtained using the basic case

INTERACTION BETWEEN SEABIRDS AND SPANISH SURFACE LONGLINE TARGETING SWORDFISH IN THE INDIAN OCEAN (LAT ≥ 25º SOUTH) DURING THE PERIOD 2011-2015

A total of 310 fishing sets (361,608 hooks) targeting swordfish in the Indian Ocean (lat ≥ 25ºS) between 2011-2015 were analyzed. The areas included in the study are between 25º-36ºS and 34º-72ºE. However, the interaction with seabirds was restricted to areas between 31º-36ºS and 37º-48ºE during the January-April period. A total of 19 seabird individuals during the whole period 2011-2015, identified as belonging to seven species, interacted with the fishing operation (Diomedea exulans, Phoebetria fusca, Procellaria aequinoctialis, Thalassarche carteri, Thalassarche cauta, Thalassarche melanophris, Thalassarche salvini). Most interactions occurred in one year-months and in a single 5ºx5º square. Interactions observed in other areas were minor or regularly null. The overall rate of interaction estimated for areas lat ≥ 25ºS and species combined was estimated at 5.254E-05 seabird/hook. Night setting and low levels of lighting during setting operations as well as other fishing protocols applied by the vessels were identified as the most important factors to explain the regularly low or null interaction with seabirds. Sightings of seabirds were also made during the trips studied, most of them occurring during daytime sailing. Procellaria aequinoctialis was identified as the most prevalent species in sightings. Other less prevalent species were identified as Phoebetria fusca, Thalassarche carteri, Diomedea exulans, Thalassarche cauta, Pterodroma macroptera, Thalassarche salvini and very sporadically Sulidae/Laridae, Oceanites spp. and Ardena pacifica.The paper also summarizes the mitigation regulations put in place at national level for reducing the incidental bycatch of seabirds in the longline fleet in the Indian Ocean

Ricci flow, quantum mechanics and gravity

It has been argued that, underlying any given quantum-mechanical model, there exists at least one deterministic system that reproduces, after prequantisation, the given quantum dynamics. For a quantum mechanics with a complex d-dimensional Hilbert space, the Lie group SU(d) represents classical canonical transformations on the projective space CP^{d-1} of quantum states. Let R stand for the Ricci flow of the manifold SU(d-1) down to one point, and let P denote the projection from the Hopf bundle onto its base CP^{d-1}. Then the underlying deterministic model we propose here is the Lie group SU(d), acted on by the operation PR. Finally we comment on some possible consequences that our model may have on a quantum theory of gravity.Comment: 8 page

Is the Voter Model a model for voters?

The voter model has been studied extensively as a paradigmatic opinion dynamics' model. However, its ability for modeling real opinion dynamics has not been addressed. We introduce a noisy voter model (accounting for social influence) with agents' recurrent mobility (as a proxy for social context), where the spatial and population diversity are taken as inputs to the model. We show that the dynamics can be described as a noisy diffusive process that contains the proper anysotropic coupling topology given by population and mobility heterogeneity. The model captures statistical features of the US presidential elections as the stationary vote-share fluctuations across counties, and the long-range spatial correlations that decay logarithmically with the distance. Furthermore, it recovers the behavior of these properties when a real-space renormalization is performed by coarse-graining the geographical scale from county level through congressional districts and up to states. Finally, we analyze the role of the mobility range and the randomness in decision making which are consistent with the empirical observations.Comment: 13 pages, 13 figure

Modular Planar Antenna at X-band for satellite communications

An antenna which has been conceived as a portable system for satellite communications based on the recommendations ITU-R S.580-6 [1] and ITU-R S.465-5 [2] for small antennas, i.e., with a diameter lower than 50 wavelengths, is introduced. It is a planar and a compact structure with a size of 40×40×2 cm. The antenna is formed by an array of 256 printed elements covering a large bandwidth (14.7%) at X-Band. The specification includes transmission (Tx) and reception (Rx) bands simultaneously. The printed antenna has a radiation pattern with a 3dB beamwidth of 5°, over a 31dBi gain, and a dual and an interchangeable circular polarizatio