14 research outputs found
Distribution, social structure and habitat use of short-finned pilot whale, Globicephala macrorhynchus, in the Canary Islands
The Canary Archipelago is considered one of the planetâs biodiversity hotspots and the
short-finned pilot whale is a key species in need of conservation measures. To address a
lack of knowledge, almost 2,000 day-surveys were conducted (1999-2012) resulting in
1,094 short-finned pilot whale sightings. The species was recorded year-round and
distributed non-uniformly around the archipelago, with greater densities concentrated in
patchy areas mainly on the leeward side of the main islands. A total of 1,320 well-marked individuals were identified, which exhibited a large degree of variability in site
fidelity (from core residents to transients). Evidence of an island-associated sub-population and a transient one was found. Longitudinal data were used to infer
population structure and estimate abundance, while a spatial modelling approach was
used to study spatio-temporal patterns in habitat use, distribution and abundance.
Spatial modelling revealed habitat preferences in areas between depths of 1000m and
1500m, and higher densities in the south-west of Tenerife and La Gomera (117 short-finned pilot whales recaptured within the two islands). Abundance of 1,980 individuals
(CV = 0.33, 95% CI=1,442 â 2,324) was estimated for the entire archipelago, with higher
density predicted during the summer months. Mark-recapture analysis estimated 636
resident individuals (CV = 0.028, 95% CI=602 - 671) in the southwest waters of Tenerife
between 2007 and 2009.
The social and temporal analyses of the behavioural relationships between pairs of
individuals revealed a well-differentiated society with long-lasting and non-random social
structure built of constant companions. A hierarchical social system is proposed
composed of a population encompassing several clans of pilot whales, each one
containing several pods. Nine long-term units were identified with a high degree of
association (0.62 - 0.83).
This study, the first to provide combined results on distribution, habitat use, and social
structure of the species, provides essential information towards the development of
recommendations for much needed conservation measures
Multipoint Turbulence Analysis with Helioswarm
Exploration of plasma dynamics in space, including turbulence, is entering a
new era of multi-satellite constellation measurements that will determine
fundamental properties with unprecedented precision. Familiar but imprecise
approximations will need to be abandoned and replaced with more advanced
approaches. We present a preparatory study of the evaluation of second- and
third-order statistics, using simultaneous measurements at many points. Here,
for specificity, the orbital configuration of the NASA Helioswarm mission is
employed in conjunction with three-dimensional magnetohydrodynamics numerical
simulations of turbulence. The Helioswarm 9-spacecraft constellation flies
virtually through the turbulence to compare results with the exact numerical
statistics. We demonstrate novel increment-based techniques for the computation
of (1) the multidimensional spectra and (2) the turbulent energy flux. This
latter increment-space estimate of the cascade rate, based on the third-order
Yaglom-Politano-Pouquet theory, uses numerous increment-space tetrahedra. Our
investigation reveals that Helioswarm will provide crucial information on the
nature of astrophysical turbulence
Current Sheets, Magnetic Islands, and Associated Particle Acceleration in the Solar Wind as Observed by Ulysses near the Ecliptic Plane
Recent studies of particle acceleration in the heliosphere have revealed a new mechanism that can locally energize particles up to several MeV nucleonâ1. Streamâstream interactions, as well as the heliospheric current sheet (CS)âstream interactions, lead to formation of large magnetic cavities, bordered by strong CSs, which in turn produce secondary CSs and dynamical small-scale magnetic islands (SMIs) of ~0.01 au or less owing to magnetic reconnection. It has been shown that particle acceleration or reacceleration occurs via stochastic magnetic reconnection in dynamical SMIs confined inside magnetic cavities observed at 1 au. The study links the occurrence of CSs and SMIs with characteristics of intermittent turbulence and observations of energetic particles of keVâMeV nucleonâ1 energies at ~5.3 au. We analyze selected samples of different plasmas observed by Ulysses during a widely discussed event, which was characterized by a series of high-speed streams of various origins that interacted beyond Earth's orbit in 2005 January. The interactions formed complex conglomerates of merged interplanetary coronal mass ejections, stream/corotating interaction regions, and magnetic cavities. We study properties of turbulence and associated structures of various scales. We confirm the importance of intermittent turbulence and magnetic reconnection in modulating solar energetic particle flux and even local particle acceleration. Coherent structures, including CSs and SMIs, play a significant role in the development of secondary stochastic particle acceleration, which changes the observed energetic particle flux timeâintensity profiles and increases the final energy level to which energetic particles can be accelerated in the solar win
Emergence of intermittent structures and reconnection in MHD turbulence
In recent analyses of numerical simulation and solar wind dataset, the idea that the magnetic discontinuities may be related to intermittent structures that appear spontaneously in MHD turbulence has been explored in details. These studies are consistent with the hypothesis that discontinuity events founds in the solar wind might be of local origin as well, i.e. a by-product of the turbulent evolution of magnetic fluctuations. Using simulations of 2D MHD turbulence, we are exploring a possible link between tangential discontinuities and magnetic reconnection. The goal is to develop numerical algorithms that may be useful for solar wind applications. © 2011 International Astronomical Union.Fil: Greco, Antonella. UniversitĂ della Calabria; ItaliaFil: Servidio, Sergio. UniversitĂ della Calabria; ItaliaFil: Matthaeus, William H.. University of Delaware; Estados UnidosFil: Dmitruk, Pablo Ariel. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Instituto de FĂsica de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de FĂsica de Buenos Aires; Argentin
Molecular detection of Treponema denticola and Porphyromonas gingivalis in carotid and aortic atheromatous plaques by FISH:report of two cases
none10noneCAVRINI F; SAMBRI V; MOTER A; SERVIDIO D; MARANGONI A; MONTEBUGNOLI L; FOSCHI F; PRATI C.; DI BARTOLOMEO R; CEVENINI RCAVRINI F; SAMBRI V; MOTER A; SERVIDIO D; MARANGONI A; MONTEBUGNOLI L; FOSCHI F; PRATI C.; DI BARTOLOMEO R; CEVENINI