1,721,093 research outputs found
Temporal variations of zooplankton biomass in the Ligurian Sea inferred from long time series of ADCP data
No full textThree years of 300 kHz acoustic doppler current profiler data collected in the central Ligurian Sea are analysed to investigate the variability of the zooplankton biomass and the diel vertical migration in the upper thermocline. After a pre-processing phase aimed at avoiding the slant range attenuation, hourly volume backscattering strength time series are obtained. Despite the lack of concurrent net samples collection, different migration patterns are identified and their temporal variability examined by means of time-frequency analysis. The effect of changes in the environmental condition is also investigated. The highest zooplankton biomasses are observed in April-May just after the peak of surface primary production in March-April. The main migration pattern found here points to a "nocturnal" migration, with zooplankton organisms occurring deeper in the water column during the day and shallower at night. Also, twilight migration is highlighted during this study. The largest migrations are recorded in November-December, corresponding to lowest backscattering strength values and they are likely attributable to larger and more active organisms (i.e. euphausiids and mesopelagic fish). The results suggest further applications of the available historical acoustic doppler current profiler time series. © 2014 Author(s)
Environmental acoustic noise observations in Tethys Bay (Terra Nova Bay, Ross Sea, Antarctica)
No full textUnderwater acoustic measurements have been recently carried out in Tethys Bay (Ross Sea, Antarctica) during the XXIX Italian Antarctic Expedition to support acoustic propagation studies in the area and to investigate the environmental noise. Tethys Bay is a small deep cove close to the Antarctic Italian base Mario Zucchelli Station (Baia Terra Nova -74°42' S e 164°07' E) and covered with sea-ice for most of the year. During the period of the experiment (November 2013) the pack-ice had an almost constant thickness of about 2.2 m, so that the measurements were performed deploying the instruments into the sea from holes drilled through the pack ice. The holes were located along the bay axis at a distance of about 500 m each other. The sea depth was around 200 m except for the hole close to the coast, where the sea depth was only 25 m. An hydrophone RESON TC 4032 was located in the outermost hole, while the acoustic source, a transceiver transmitting FSK pulses at 11 kHz, was placed in sequence in the other three holes. Every time, the measurements were performed at 0, 20 and 45 m depth for each configuration. Furthermore during the experiment, sea temperature, salinity and currents, as well as the main meteorological parameters were continuously measured. The analysis here reported mainly focuses on the acquired acoustic passive data. The passive measurements evidenced that the signal was generally dominated by different sounds from seals, which was prevailing on the noise due to human activities. © 2014 IEEE
Weak large deviations principle for one dimensional random field Kac model
No full textWe present a quenched weak large deviations principle for the Gibbs measures of
a Random Field Kac Model (RFKM) in one dimension. The external random magnetic field is
given by symmetrically distributed Bernouilli random variables. The results are valid for
values of the temperature and magnitude
of the field in the region
where the free energy of the corresponding random Curie Weiss
model has only two absolute minimizers.
We give an explicit representation of the large deviation rate function
and characterize its minimizers.
We show that they are step functions taking two values, the two absolute minimizers of the
free energy of the random Curie Weiss
model. The points of discontinuity are
described by a stationary renewal process related to the extrema of
a bilateral Brownian motion studied by Neveu and Pitman,
where depends on the temperature and magnitude of the random field. Our result is a complete
characterization of the typical profiles of RFKM (the ground states) which was initiated in
[\rcite{COP1}] and extended in [\rcite{COPV}]
Co-expression of wild-type and mutant olfactory cyclic nucleotide-gated channels: restoration of the native sensitivity to Ca2+ and Mg2+ blockage
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Blood glucose normalization induced haemolysis in boys with IDDM at onset and unknown G-6PD deficiency.
No full textWe present three adolescents unknown to be G-6-PD deficient who developed haemolytic anaemia after admission for diabetes at onset uncomplicated by ketoacidosis. These patients had no bacterial infections and had not ingested haemolytic drugs. The fall in glucose availability after the correction of hyperglycaemia is proposed as capable of inducing haemolysis in G-6-PD deficiency
One-Dimensional Ising Models with Long Range Interactions: Cluster Expansion, Phase-Separating Point
No full textWe consider the phase separation problem for the one-dimensional ferromagnetic
Ising model with long-range two-body interaction, J (n) = n−2+α, where n ∈ N
denotes the distance of the two spins and α ∈ [0, α+[ with α+ = (log 3)/(log 2)−1.We
prove that when α = 0 the localization of the phase separation fluctuates macroscopically
with a non-uniform explicit limiting law, while when 0 < α < α+ the macroscopic
fluctuations disappear and mesoscopic ones appear with a gaussian behavior when conveniently
scaled. The mean magnetization profile is also given
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