1435 research outputs found
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Acclimatisation of farm-reared red-legged partridges (Alectoris rufa L.) in two protected areas of southern Tuscany
No full textSUMMARY Results of a red-legged partridge (Alectoris rufa L.) reintroduction program in two protected areas in southern Tuscany are reported and discussed (7.51 and 7.01 square km each). A total of 2475 farm-reared partridges were released from 2000 to 2005. Spring pair density, pair reproduction success and brood size was seasonally monitored, in order to evaluate the success of the reintroduction program. The strong correlation (r = 0.93***) between the number of the spring pairs and the number of the summer released birds, the constant (b = +0.00042) low density (avg. 2.47) of the spring population, and the low level of every population dynamic parameter (always lower than those observed in other studies carried out in Tuscany or other Italian regions) suggests the need of a change in the project strategy. A reduction in the number linked with an improve of the quality of the released birds (by the use of partridges hutched directly by their own parents in order to improve the reproductive success), a more effective predation control program (in order to protect temporaneously the weak reintroduced animals), an habitat improvement with an eventually seasonally food supply (to improve the short time-survival after release), and a hunting stop or, at least, a more strictly regulated harvesting in the areas surrounding the protected areas (bag limit and shorter season), must be attempted to improve the low observed population dynamic parameters. RIASSUNTO Si riportano i risultati di un esperimento di reintroduzione della pernice rossa (Alectoris rufa L.) in due aree protette della Toscana meridionale (provincia di Grosseto), una di 7,51 kmq e l’altra di 7,01 kmq. In totale, dal 2000 al 2005, sono state ambientate nelle due aree 2.475 pernici rosse di allevamento provenienti da un centro pubblico di produzione di selvaggina. La popolazione è stata censita stagionalmente al fine di determinare la densità primaverile delle coppie ed il successo riproduttivo (numero di nidiate e numero medio di piccoli per nidiata). La densità è rimasta pressoché costantemente (b= +0,00042) ad un livello inferiore (media 2,47) a quello riscontrato in altre esperienze condotte in Italia ed in Toscana. Inoltre si è riscontrata una stretta correlazione fra il numero delle coppie censite in primavera con il numero di soggetti ambientati durante l’estate (r = 0,93***). Per questo motivo si suggerisce di apportare alcuni correttivi alla strategia del progetto. In primo luogo appare necessario sospendere o diminuire il numero di animali allevati immessi annualmente o, in alternativa, immettere soggetti provenienti da allevamento semi-naturale (covati ed allevati dai genitori) in modo da migliorarne il successo riproduttivo e dovrebbe essere inoltre realizzato un più efficiente controllo della predazione. Altre misure gestionali come dei miglioramenti ambientali a fini faunistici ed una integrazione alimentare mirata potrebbero consentire un miglioramento dei parametri della popolazione. Dovrebbe infine essere valutata la sospensione dell’attività venatoria od almeno una più severa regolamentazione della stessa almeno nei dintorni delle aree protette con limitazione dei carnieri e/o del periodo di caccia alla specie
Antonio Valente architetto al cinema
Get PDFProgettista della Pisorno, la prima città del cinema in Italia, del Centro Sperimentale di Cinematografia, nonché fine scenografo e costumista, Antonio Valente è un personaggio chiave nel panorama italiano per comprendere a fondo il "cantiere del film". Infaticabile costruttore di finzioni, in equilibrio felicemente precario tra innovazione tecnologica e tradizione figurativa, Valente ha lavorato per oltre quarant’anni nel cinema, esercitando una professionalità di alto profilo. Il volume, corredato di un ricco apparato iconografico e documentario, propone un ritratto di questo "architetto del cinema", attivo in ogni fase della "costruzione dell’artificio", dal teatro di posa, al set e alla sala, eppure in parte dimenticato, rimosso. Il saggio "Antonio Valente architetto al cinema", in particolare, illustra la formazione dell'artista sorano e ne inserisce la produzione architettonica nel clima culturale italiano e internazionale, evidenziando i vari momenti della carriera di Valente come tappe della sua vocazione di "scenarchitetto" e progettista di teatri di posa e sale cinematografiche
Paesaggio ed architettura della Certosa di Calci. Il progetto di conoscenza e trasformazione dell’uso
Get PDFI certosini hanno abitato la Certosa fino al 1972 quando ormai la comunità ridotta a sole due persone viene definitivamente chiusa. Nel 1978 la Certosa è concessa in uso all’Università di Pisa, infatti qui si trova un importante Museo di Scienze Naturali e del Territorio dell’Ateneo Pisano. Si pongono così le basi per una riflessione ed analisi sul tema del riuso e della fruizione del Bene in cui proprio la conoscenza storica e materiale determina la volontà stessa di conservazion
Nonlinear impact monitoring: line of variation searches for impactors
No full textSUMMARY When a new near Earth asteroid is discovered, it is important to know whether or not there is the possibility of an impact with the Earth in the near future. In this paper, we describe the technical approaches employed by the two operational second-generation asteroid impact monitoring systems, CLOMON2 and Sentry, paying particular attention to the similarities and differences between these independent systems. The detection and characterization of a potential impact requires the propagation of the orbital probability density function from the time of discovery to the time of hypothetical impact. Since the N-body problem is not integrable, this can be done only by sampling the orbital elements space with a finite number of Virtual Asteroids (VAs), the orbit of each one being propagated numerically. Our methods, illustrated in this paper, use the Line Of Variation (LOV), a unidimensional subspace, to perform this sampling. The primary goal is to detect Virtual Impactors (VIs), which are regions in the initial conditions space leading to dynamically distinct collision solutions; then a probability integral needs to be computed on the volume of the VI. An important issue is how to assure completeness of such a search down to some impact probability threshold. This problem cannot be efficiently solved just by computing more VAs, but requires a geometric description of the behavior of the LOV in order to identify the critical segments of this curve. We have studied these behaviors on the Target Plane (TP) through our analytical theory and the output of many numerical tests. Assuming that the geometry is the simplest compatible with the data available from the sampling, we obtain a classification which allows us to use iterative methods, appropriate for each case, to find the closest approach distance possible along the LOV. After an LOV minimum has been identified, it is possible to use a probability density linearized at this point. However, when the cross section of the Earth is not crossed by the LOV, there is no guarantee that nonlinearity would be negligible in the direction on the TP transversal to the LOV. We describe how to test for such nonlinearity, and thus reduce or eliminate the possibility of spurious VIs. In this way, the performance of our impact monitoring systems has been significantly increased in comparison to the earlier and simpler solitary system. These more advanced systems have identified and then eliminated (through additional observations) more than one hundred cases of asteroids with VIs in the years 2002–2003
The finite-temperature chiral transition in QCD with adjoint fermions
No full textWe study the nature of the finite-temperature chiral transition in QCD with
N_f light quarks in the adjoint representation (aQCD). Renormalization-group
arguments show that the transition can be continuous if a stable fixed point
exists in the renormalization-group flow of the corresponding three-dimensional
Phi^4 theory with a complex 2N_f x 2N_f symmetric matrix field and
symmetry-breaking pattern SU(2N_f)->SO(2N_f). This issue is investigated by
exploiting two three-dimensional perturbative approaches, the massless
minimal-subtraction scheme without epsilon expansion and a massive scheme in
which correlation functions are renormalized at zero momentum. We compute the
renormalization-group functions in the two schemes to five and six loops
respectively, and determine their large-order behavior.
The analyses of the series show the presence of a stable three-dimensional
fixed point characterized by the symmetry-breaking pattern SU(4)->SO(4). This
fixed point does not appear in an epsilon-expansion analysis and therefore does
not exist close to four dimensions. The finite-temperature chiral transition in
two-flavor aQCD can therefore be continuous; in this case its critical behavior
is determined by this new SU(4)/SO(4) universality class. One-flavor aQCD may
show a more complex phase diagram with two phase transitions. One of them, if
continuous, should belong to the O(3) vector universality class
Finite-temperature chiral transition in QCD with quarks in the fundamental and adjoint representation
No full textWe study the nature of the finite-temperature chiral transition in QCD with
N_f light quarks in the fundamental and adjoint representation. Universality
and renormalization-group (RG) arguments show that the possibility of having a
continuous transition is related to the existence of a stable fixed point (FP)
in the RG flow of a 3D Landau-Ginzburg-Wilson Phi^4 theory with the same chiral
symmetry-breaking pattern. The RG flow of these theories is studied by
field-theoretical approaches, computing and analyzing high-order perturbative
series, up to six loops. According to this RG analysis, the transition in QCD
can be continuous only for N_f=2. In this case it belongs to the 3D O(4)
universality class. We also find a stable FP corresponding to a 3D universality
class with symmetry breaking U(2)_L x U(2)_R -> U(2)_V, which implies that the
transition can be continuous also if the axial-anomaly effects are suppressed
at Tc. In the case of quarks in the adjoint representation, we can have a
continuous transition for N_f=1,2. For N_f=1 it belongs to the O(3)
universality class. For N_f=2 it belongs to a new 3D universality class
characterized by the symmetry breaking SU(4)->SO(4)
k-Restricted Rotation with an Application to Search Tree Rebalancing
No full textThe restricted rotation distance d_{R}(S,T)
between two binary trees S, T of n
vertices is the minimum number of rotations by which S can be
transformed into T, where rotations can only take place
at the root of the tree, or at the right child of the root.
A sharp upper bound d_{R}(S,T) \leq 4n-8 is known,
based on the word metric of Thompson's group.
We refine this bound to a sharp
d_{R}(S,T) \leq 4n-8-\rho_{S}-\rho_{T}, where
\rho_{S} and \rho_{T} are the numbers of vertices in the rightmost
vertex chains of the two trees, by means of a very simple transformation
algorithm based on elementary
properties of trees.
We then generalize the concept of restricted rotation to k-restricted
rotation, by allowing rotations
to take place at all the vertices of the highest k levels of the tree.
For k=2 we show that not much is gained in the worst case,
although the classical problem of rebalancing an AVL tree
can be solved efficiently, in particular rebalancing after vertex deletion
requires O(log n) rotations as in the standard algorithm.
Finding significant bounds and applications for
k \geq 3 is open
A compression-based approach for coding sequences identification in prokaryotic genomes
No full textTo identify coding regions in genomic sequences represents the first step toward further analysis of the biological function carried on by the different functional elements in a genome. The present paper presents a novel method for the classification of coding and non-coding regions in prokaryotic genomes, based on a suitable defined compression index of a DNA sequence. The proposed approach has been applied on some prokaryotic complete genomes, obtaining optimal scores of correctly recognized coding and non-coding regions. Several false-positive and false-negative cases have been investigated in detail, discovering that this approach can fail in the presence of highly-structured coding regions (e.g., genes coding for modular proteins) or quasi-random non-coding regions (regions hosting non-functional fragments of copies of functional genes; regions hosting promoters or other protein-binding sequences, etc.)
Generalized inverses of band matrices
No full textIn 1959 Edgar Asplund presented a geometric lemma that largely anticipated many results on the structure of inverses of band matrices. In this note we discuss an extension of Asplund's lemma that addresses the concept of generalized inverse,in particular the Moore-Penrose inverse
Asymptotics of an optimal compliance-location problem
No full textSUMMARY We consider the problem of placing n small balls of given radius in a certain
domain subject to a force f in order to minimize the compliance of the
configuration. Then we let n tend to infinity and look at the asymptotics of
the minimization problem, after properly scaling the functionals involved, and
to the limit distribution of the centres of the balls. This problem is both
linked to optimal location and shape optimization problems