1,766 research outputs found
An Integrated Coastal Sediment Management Plan: The Example of the Tuscany Region (Italy)
This paper presents the results of a study carried out to support the Region of Tuscany Coastal Sediment Management Plan, with the main aim of establishing the sediment budget considering the time span from 1981-1985 to 2005 for the 56 coastal sectors into which the 215 km-long continental sandy coast of Tuscany (Italy) was divided. The sand stability (according to a stability index) and colour compatibility (according to the CIEL*a*b* colour space with an acceptability range conforming to national guidelines) were determined in order to assess the possibility of using the available sediment in accreting sectors to nourish the beach in eroding areas. Only in two cases-i.e., the updrift of a harbour (at Viareggio) and in a convergence zone (at Marina di Pietrasanta)-are the volumes of sufficient magnitude to support a large nourishment project; however, the mean sand size is too small to guarantee efficient nourishment, even with medium-term stability. In contrast, the colour difference, in most of the cases, was shown to be acceptable. Other small sediment stocks, suitable for colour but not for grain size, can be used for periodic ephemeral nourishment works to support seasonal tourist activities. The limited resources available make it necessary to adopt a plan for their optimal use from a regional perspective. This kind of study is of great interest for the proposal of sound management actions to counteract the increasing erosion processes linked to climate change phenomena and human effects on rivers and coastal systems
Morphochemical age-related changes in the nematode Caenorhabditis elegans: immunoperoxidase localization of cytokine- and growth factor-like molecules
Morphochemical age-related features in the hermaphrodite Caenorhabditis elegans are reported. The study of worms of different ages shows a gradual decline in response to the various histochemical reactions and a disorganization of the components of the gonad during ageing. Using an immunocytochemical procedure, we show for the first time the presence of immunoreactive IL-1alpha and PDGF-AB molecules in neurons from young adult C. elegans. Moreover, TNF-alpha- and PDGF-AB-like molecules are also present in the secretory cells of the pharyngeal terminal bulb. The number of positive cells to anti-cytokine and anti-growth factor antibodies decreases in older worms, suggesting that these molecules may play an important role in worm ageing. The present investigation therefore supports the findings in the literature obtained with different approaches on the crucial role of the nervous and reproductive systems in the life span of C. elegans
On prefix palindromic length of automatic words
The prefix palindromic length of an infinite
word is the minimal number of concatenated palindromes needed to
express the prefix of length of . Since 2013, it is still
unknown if is unbounded for every aperiodic
infinite word , even though this has been proven for almost all
aperiodic words. At the same time, the only well-known nontrivial infinite word
for which the function has been precisely
computed is the Thue-Morse word . This word is -automatic and,
predictably, its function is -regular, but is
this the case for all automatic words?
In this paper, we prove that this function is -regular for every
-automatic word containing only a finite number of palindromes. For two such
words, namely the paperfolding word and the Rudin-Shapiro word, we derive a
formula for this function. Our computational experiments suggest that generally
this is not true: for the period-doubling word, the prefix palindromic length
does not look -regular, and for the Fibonacci word, it does not look
Fibonacci-regular. If proven, these results would give rare (if not first)
examples of a natural function of an automatic word which is not regular.Comment: revised version, to appear in Theoret. Comput. Sc
Exoplanet atmospheres with EChO: spectral retrievals using EChOSim
We demonstrate the effectiveness of the Exoplanet Characterisation
Observatory mission concept for constraining the atmospheric properties of hot
and warm gas giants and super Earths. Synthetic primary and secondary transit
spectra for a range of planets are passed through EChOSim (Waldmann & Pascale
2014) to obtain the expected level of noise for different observational
scenarios; these are then used as inputs for the NEMESIS atmospheric retrieval
code and the retrieved atmospheric properties (temperature structure,
composition and cloud properties) compared with the known input values,
following the method of Barstow et al. (2013a). To correctly retrieve the
temperature structure and composition of the atmosphere to within 2 {\sigma},
we find that we require: a single transit or eclipse of a hot Jupiter orbiting
a sun-like (G2) star at 35 pc to constrain the terminator and dayside
atmospheres; 20 transits or eclipses of a warm Jupiter orbiting a similar star;
10 transits/eclipses of a hot Neptune orbiting an M dwarf at 6 pc; and 30
transits or eclipses of a GJ1214b-like planet.Comment: 13 pages, 15 figures, 1 table. Accepted by Experimental Astronomy.
The final publication will shortly be available at Springer via
http://dx.doi.org/10.1007/s10686-014-9397-
A Non-Disordered Glassy Model with a Tunable Interaction Range
We introduce a non-disordered lattice spin model, based on the principle of
minimizing spin-spin correlations up to a (tunable) distance R. The model can
be defined in any spatial dimension D, but already for D=1 and small values of
R (e.g. R=5) the model shows the properties of a glassy system: deep and well
separated energy minima, very slow relaxation dynamics, aging and non-trivial
fluctuation-dissipation ratio.Comment: 4 pages, 5 figure
Composition of processes and related partial differential equations
In this paper different types of compositions involving independent
fractional Brownian motions B^j_{H_j}(t), t>0, j=1,$ are examined. The partial
differential equations governing the distributions of
I_F(t)=B^1_{H_1}(|B^2_{H_2}(t)|), t>0 and
J_F(t)=B^1_{H_1}(|B^2_{H_2}(t)|^{1/H_1}), t>0 are derived by different methods
and compared with those existing in the literature and with those related to
B^1(|B^2_{H_2}(t)|), t>0. The process of iterated Brownian motion I^n_F(t), t>0
is examined in detail and its moments are calculated. Furthermore for
J^{n-1}_F(t)=B^1_{H}(|B^2_H(...|B^n_H(t)|^{1/H}...)|^{1/H}), t>0 the following
factorization is proved J^{n-1}_F(t)=\prod_{j=1}^{n} B^j_{\frac{H}{n}}(t), t>0.
A series of compositions involving Cauchy processes and fractional Brownian
motions are also studied and the corresponding non-homogeneous wave equations
are derived.Comment: 32 page
Disentangling age and metallicity in distant unresolved stellar systems
We present some results of an observational and theoretical study on
unresolved stellar systems based on the Surface Brightness Fluctuations (SBF)
technique. It is shown that SBF magnitudes are a valuable tracer of stellar
population properties, and a reliable distance indicator. SBF magnitudes,
SBF-colors, and SBF-gradients can help to constrain within relatively narrow
limits the metallicity and age of the dominant stellar component in distant
stellar systems, especially if coupled with other spectro-photometric
indicators.Comment: A contributed paper to the Cefalu' (Italy) "Probing Stellar
Populations out to the Distant Universe", 4 pages. To appear as an AIP
Conference Proceedin
Analysis of cosmic ray variations observed by the CARPET in association with solar flares in 2011-2012
The CARPET cosmic ray detector was installed on April 2006 at CASLEO (Complejo Astronmico El Leoncito) at the Argentinean Andes (31.8S, 69.3W, 2550 m, Rc=9.65 GV). This instrument was developed within an international cooperation between the Lebedev Physical Institute RAS (LPI; Russia), the Centro de Radio Astronomia e Astrofsica Mackenzie (CRAAM; Brazil) and the Complejo Astronmico el Leoncito (CASLEO; Argentina). In this paper we present results of analysis of cosmic ray variations recorded by the CARPET during increased solar flare activity in 2011-2012. Available solar and interplanetary medium observational data obtained onboard GOES, FERMI, ISS, as well as cosmic ray measurements by ground-based neutron monitor network were also used in the present analysis.Fil: Makhmutov, V.. Lebedev Physical Institute; Rusia. Universidade Presbiteriana Mackenzie; BrasilFil: Raulin, J. P.. Universidade Presbiteriana Mackenzie; BrasilFil: De Mendonca, R. R. S.. National Institute for Space Research; BrasilFil: Bazilevskaya, G. A.. Lebedev Physical Institute; RusiaFil: Correia, E.. Universidade Presbiteriana Mackenzie; Brasil. National Institute for Space Research; BrasilFil: Kaufmann, Pierre. Universidade Presbiteriana Mackenzie; BrasilFil: Marun, Adolfo Hector. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - San Juan. Complejo Astronómico "El Leoncito". Universidad Nacional de Córdoba. Complejo Astronómico "El Leoncito". Universidad Nacional de la Plata. Complejo Astronómico "El Leoncito". Universidad Nacional de San Juan. Complejo Astronómico "El Leoncito"; ArgentinaFil: Fernandez, German Enzo Leonel. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - San Juan. Complejo Astronómico "El Leoncito". Universidad Nacional de Córdoba. Complejo Astronómico "El Leoncito". Universidad Nacional de la Plata. Complejo Astronómico "El Leoncito". Universidad Nacional de San Juan. Complejo Astronómico "El Leoncito"; ArgentinaFil: Echer, E.. National Institute for Space Research; Brasi
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