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Search Results: 1 - 10 of 144862 matches for " Rocca F "
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How tall is an elephant? Two methods for estimating elephant height
F. Della Rocca
Web Ecology (WE) , 2007, DOI: 10.5194/we-7-1-2007
Abstract: Shoulder height is a reliable indicator of age for African elephants (Loxodonta africana), and is therefore an important parameter to be recorded in field studies of population ecology of these pachyderms. However, it can be somewhat difficult to estimate with precision the shoulder height of free-ranging elephants because of several reasons, including the presence of drops and vegetation cover and the potential dangerousness of approaching them in the wild. Here I test two alternative models for estimating shoulder height of elephants. In both models, the equipment needed to generate the height estimates is minimal, and include a telemeter and a digital photo-camera furnished with an ×16 zoom. The models are based respectively on a linear regression approach and on a geometric formula approach, and put into a relationship the linear distance between the observer and the animal, the number of pixels of an elephant silhouette as taken from digital photos, and the absolute height of the animal. Both methods proved to have a very small measurement error, and were thus reliable for field estimates of elephant shoulder heights. The model based on a geometric formula was used to estimate the shoulder height distribution of an elephant population in a savannah region of West Africa (Zakouma National Park, Chad). I demonstrated that Zakouma elephants were among the tallest populations in Africa, with growth rates being highest throughout the first five years of life.
Automorphism Classes of Elements in Finitely Generated Abelian Groups
Charles F. Rocca Jr
Mathematics , 2011,
Abstract: We will show that every element of a finitely generated abelian group is automorphically equivalent what we will define to be a {\em representative element} in a {\em repeat-free subgroup}, and for finite abelian groups we can count the number of automorphism classes of elements.
Towards constructing Tsallis' q-Coherent States
F. Pennini,A. Plastino,M. C. Rocca
Physics , 2015,
Abstract: In this manuscript we define q-coherent states corresponding to the Tsallis' statistics. For them and for the ordinary coherent states we calculate the respective distributions of probabilities. For the latter, we encounter some results that are not too well known and deserve better dissemination.
Classical thermodynamics from quasi-probabilities
F. Pennini,A. Plastino,M. C. Rocca
Physics , 2015,
Abstract: The basic idea of a microscopic understanding of Thermodynamics is to derive its main features from a microscopic probability distribution. In such a vein, we investigate the thermal statistics of quasi-probabilities's semi-classical analogs in phase space for the important case of quadratic Hamiltonians, focusing attention in the three more important instances, i.e., those of Wigner, $P$-, and Husimi distributions. Introduction of an effective temperature permits one to obtain a unified thermodynamic description that encompasses and unifies the three different quasi-probability distributions. This unified description turns out to be classical.
Cooperative Learning Online in Higher Education. Second Experience at Roma Tre University, Italy  [PDF]
Concetta La Rocca
Open Journal of Social Sciences (JSS) , 2015, DOI: 10.4236/jss.2015.34011
Abstract: This study presents the procedures and results of online cooperative learning activities carried out by the students in the a.y. 2013/14 in two academic courses at the Department of Education at Roma Tre University (Italy): “General Didactic” (GD), First-level Degree in Education Sciences and “Educational Strategies and New Communication Processes” (ES), Second-level Degree in Professional Community Educator. It constitutes the continuation of the first pilot study, carried out only in the teaching of GD in the academic year 2012/13 which has already been reported in a previous publication [1]; this second experience is built in a perspective of continuity and difference from the first one. This study is divided into two interventions: a) description and analysis of the data collected following the administration of a questionnaire, said barometer, developed to detect the climate experienced by the students involved in the online working groups; b) investigation of the relapse that collaborative activities produced on the performance. In particular, we observe that the average mark obtained in the exam of “General Didactics” by the students in cooperative is on average higher than others, and that in the first group there is less “sigma” compared to the second group.
Spigelian hernia in the elderly
Giamattei R M,Butuc L,La Rocca F,Viola G
BMC Geriatrics , 2011, DOI: 10.1186/1471-2318-11-s1-a20
Slow group velocity and Cherenkov radiation
I. Carusotto,M. Artoni,G. C. La Rocca,F. Bassani
Physics , 2001, DOI: 10.1103/PhysRevLett.87.064801
Abstract: We theoretically study the effect of ultraslow group velocities on the emission of Vavilov-Cherenkov radiation in a coherently driven medium. We show that in this case the aperture of the group cone on which the intensity of the radiation peaks is much smaller than that of the usual wave cone associated with the Cherenkov coherence condition. We show that such a singular behaviour may be observed in a coherently driven ultracold atomic gas.
The influence of persuasion in opinion formation and polarization
C. E. La Rocca,L. A. Braunstein,F. Vazquez
Computer Science , 2014, DOI: 10.1209/0295-5075/106/40004
Abstract: We present a model that explores the influence of persuasion in a population of agents with positive and negative opinion orientations. The opinion of each agent is represented by an integer number $k$ that expresses its level of agreement on a given issue, from totally against $k=-M$ to totally in favor $k=M$. Same-orientation agents persuade each other with probability $p$, becoming more extreme, while opposite-orientation agents become more moderate as they reach a compromise with probability $q$. The population initially evolves to (a) a polarized state for $r=p/q>1$, where opinions' distribution is peaked at the extreme values $k=\pm M$, or (b) a centralized state for $r<1$, with most opinions around $k=\pm 1$. When $r \gg 1$, polarization lasts for a time that diverges as $r^M \ln N$, where $N$ is the population's size. Finally, an extremist consensus ($k=M$ or $-M$) is reached in a time that scales as $r^{-1}$ for $r \ll 1$.
Educational cosmic ray experiments with Geiger counters
F. Blanco,F. Fichera,P. La Rocca,F. Librizzi,O. Parasole,F. Riggi
Physics , 2006, DOI: 10.1393/ncc/i2005-10238-6
Abstract: Experiments concerning the physics of cosmic rays offer to high-school teachers and students a relatively easy approach to the field of research in high energy physics. The detection of cosmic rays does not necessarily require the use of sophisticated equipment, and various properties of the cosmic radiation can be observed and analysed even by the use of a single Geiger counter. Nevertheless, the variety of such kind of experiments and the results obtained are limited because of the inclusive nature of these measurements. A significant improvement may be obtained when two or more Geiger counters are operated in coincidence. In this paper we discuss the potential of performing educational cosmic ray experiments with Geiger counters. In order to show also the educational value of coincidence techniques, preliminary results of cosmic ray experiments carried out by the use of a simple coincidence circuit are briefly discussed.
Multi-Resolution Retrieval of Non-Measurable Equivalent Currents in Microwave Imaging Problems-Experimental Assessment
Paolo Rocca
PIER , 2009, DOI: 10.2528/PIER09072004
Abstract: In this paper, an approach based on a multi-scaling strategy for the reconstruction of the non-measurable components of equivalent current distributions is tested against experimental data. An extensive set of simulations is carried out considering single and multiple scatterers with homogeneous as well as inhomogeneous properties. Selected results are reported and discussed to show potentialities and limitations of the method.
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