702 research outputs found
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Synthesis, characterisation and catalytic activity of metal complex of pthalocyanine with benz (b-f) azepine frame.
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Eco-ethological characterisation of the alien species vinous-throated parrotbill (Paradoxornis webbianus) and evaluation of its effects on indigenous species.
No full textThe phenomenon of exotic species (or alien) species introduction is increased in the last few years, closely connected to the increment in human activities on the global scale. In spite of the high number of introduced organisms, only few of them succeed in establishing a new range and become naturalised, that is establish self-sustaining populations. Then, only a small part of naturalised species can become an invasive species and a threat to biological diversity. There are many reasons inducing a demographic explosion of these species, in particular the lack of limiting factors such as competitors and predators presence and also the introduced species characteristics, themselves such as population growth rate, or migratory strategy can cause invasiveness.
The impact and cost of biological invasions are global and enormous, in both ecological (for example native species extinction, ecosystem alteration) and economic terms. In fact, biological invasions are the second threat to biodiversity after habitat destruction.
Parrotbills (Paradoxornis webbianus), Chinese Passeriformes, were introduced in Varese Province, north-western Italy, in 1995 by an animal trader that introduced 150 animals. In the same year these birds were found in Brabbia Marsh Natural Reserve, on southern side of Lake Varese.
The expansion of this species has been confirmed from frequent sightings since 2003 in other province areas, like Lake Comabbio, Besozzo and Bagnoli Valley, south-east of Brabbia Marsh.
Following the major international nature protection directive exhortations we carried out a multiple scale approach to study genetics and auto-ecology of this species and to understand its impact on indigenous species. In particular, the aims of this project were: to define the present species distribution, to develop knowledge on parrotbill auto-ecology, and to evaluate the potential competition with other species, evaluating parrotbill invasiveness.
We carried out 5 censuses from February 2006 to February 2008, to establish species expansion that reconfirmed the 2003 presence areas. Moreover, the area occupied by parrotbills presents several ecological corridors that can lead to an eventual future expansion.
Parrotbill were caught using mist-nets during bird ringing seasons in the Brabbia Marsh Ornithological Station. During the bird ringing operations we caught once 367 animals and 318 other animal were instead caught more than one time, for a total of 685 animals caught.
Number of caught parrotbills varied during the years, following meteorological events: in fact, population decreased after winters with high snow abundance. Using the Schnabel and the Burnham and Overton methods we calculated population size estimates. The two methods gave different results, in particular the Burnham and Overton method overrated population estimate if compared with Schnabel, but we can estimate a population between 350 to 3500 animals in Brabbia Marsh reserve.
We monitored 19 animals during different periods of the year with radio tracking technique using tags (BD-2N, Holohil Ltd, Ontario, Canada) weighing 0.43 g. Home range dimensions vary from less than an hectare (0.2-1.3 ha) in the reproductive season, to 35 hectares (20- 35 ha) in winter season, with intermediate situations during autumn, when dimension range was wider (9.5-47.5 ha). Differences in home range dimensions were statistically significant (ANOVA F (2,16) =8.9291 P= 0.003) and moreover this result is in accordance to the home range dimensions registered in the area of origin.
To analyse habitats present in the home range we used two different methods, in particular Compositional Analysis and Ivlev’s electivity index. In both cases emerged that parrotbills prefer wetland areas, in particular grey willow shrub, marsh areas.
To study parrotbills environmental perception in terms of scale we used program FRACTAL to analyse movement patterns derived from radio tracking data. The analysis of variance shows that the parrotbill spatial perception increases with scale (ANOVA F(1,476)=247.65 P<0.001) and changes with seasons (ANOVA F(2,475)=8.3953 P=0.0003). These results indicate that the potential dispersal season is during autumn, when parrotbills show a broader spatial scale perception.
To understand species auto-ecology we analysed parrotbills diet using faecal samples collected during the ringing bird sessions. Diet composition changes during the year, in particular proportion of vegetal items increased from spring to winter (ANOVA F(3,174) =142.77 P<0.001). Diet is composed in particular by Ichneumonidae, Chrysomeloidea, Carabidae, Scarabaeoidea and Araneidae. The vegetable part is composed by ate elder (Sambucus nigra), pokeweeds (Phytolacca sp.) and seeds of common reed (Phragmites australis).
We also compared the parrotbills diet with trophic spectra of 10 indigenous species using the Proportional Similarity Index the Pianka’s Overlap Index. Both methods gave similar results, the parrotbill diet resulting similar to the diet of all species considered, and the most similar
species resulted are the reed warbler (Acrocephalus scirpaceus) (PSI: 0.43; OI:0.61) and the reed bunting (Emberiza schoeniclus) (PSI: 0.34; OI:0.52).
Species invasiveness was estimated according to the “Risk assessment models for establishment of exotic vertebrates in Australia and New Zealand”. Considering all factors of this decision support model, the parrotbill invasivity risk is classified as Serious, in accordance to the Vertebrate Pest Committee of Australia.
All these results, connected with other species characteristics (generalism, large geographic original range, monogamy, monomorphic, social foraging, and non migratory strategy) suggest that the parrotbill, even if it is not yet an invasive species in our zone, could become a pest in the future
Studio degli indici di conformità di tecniche radioterapiche per il trattamento di noduli polmonari.
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Eco-ethological characterization of the alien slider Trachemy scripta and evaluation of the effects of its introduction on the conservation of Emys orbicularis.
No full textIn the field of computational linguistics, the representation of natural languages (NL) in formal grammar terms is a well-known issue and a wicked problem indeed. In fact, some formal grammars lack of lexical and semantic information representation, reducing the linguistic structure to syntax.
On the other side, approaches like dependency grammars lose expressive power, under a computational point of view. Adpositional grammars (adgrams) are a novel grammar formalism that overcomes these limitations.
Adgrams are based on Pennacchietti’s intuition, who put together Brøndal’s logic description of prepositions, Tesnerian notion of valence, Langacker’s cognitive dichotomy trajector/landmark and Silvio Ceccato’s pioneer work in the field on machine translation (MT). The result is a quasiformal description of adpositions, being the junctors of language structure.
This description is called adpositional space. Each adpositional space is made of four adpositional types: Plus (#), Minus (), Slash (!), Times ()). The resulting structure is cognitively sound and formally inspiring, as adpositional trees (adtrees) can be built as special Porphyrian trees, going beyond the Tesnerian somehow fuzzy concept of dependency.
This dissertation puts Pennacchietti’s work a step forward. In fact, here adgrams consider the ultimate unit of NLs being the morpheme, not the word, and therefore they offer a coherent theory of both morphology and syntax. Hence, the collocation phenomena are considered like zero morphemes.
Moreover, a sharp distinction in the dictionary between the adpositional space, essentially made of closed morphemes, and the lexicon, made of open morphemes. Moving again from Tesnerian structural syntax, open morphemes always have a fundamental grammar character: stative (O), adjunctive (A, as stative modifiers), and verbal (I), circumstantial (E, as verbal modifiers). The Tesnierian approach is validated through Whorf’s research results comparing grammars of typologically distant NLs.
The second part shows that adgrams are computable, as they can be implemented with a strong, robust formalism. A concrete instance of the formal model of adgrams is given through the quasi-natural language Esperanto (QNL, Lyons), showing the linguistic viability of the model. The formal model should be used appropriately in an ad hoc epistemological scenario, called ‘the translation game’, designed as a Gedankenexperiment `a la Turing. A toy example is also given. In the third part the implementation is explained with all its details: the implementation of Esperanto is made in exactly 179 logic formulas, 56 of which are predicates. The formal model is promising to be generalised for any NLs, and how to do this was explained in various points of the third part. Finally, this dissertation shows that adgrams are a powerful NL grammar formalism which is at the same time cross-linguistic, cognitively grounded and formally robust and computationally sound.
In the field of computational linguistics, the representation of natural languages (NL) in formal grammar terms is a well-known issue and a wicked problem indeed. In fact, some formal grammars lack of lexical and semantic information representation, reducing the linguistic structure to syntax.
On the other side, approaches like dependency grammars lose expressive power, under a computational point of view. Adpositional grammars (adgrams) are a novel grammar formalism that overcomes these limitations.
Adgrams are based on Pennacchietti’s intuition, who put together Brøndal’s logic description of prepositions, Tesnerian notion of valence, Langacker’s cognitive dichotomy trajector/landmark and Silvio Ceccato’s pioneer work in the field on machine translation (MT). The result is a quasiformal description of adpositions, being the junctors of language structure.
This description is called adpositional space. Each adpositional space is made of four adpositional types: Plus (#), Minus (), Slash (!), Times ()). The resulting structure is cognitively sound and formally inspiring, as adpositional trees (adtrees) can be built as special Porphyrian trees, going beyond the Tesnerian somehow fuzzy concept of dependency.
This dissertation puts Pennacchietti’s work a step forward. In fact, here adgrams consider the ultimate unit of NLs being the morpheme, not the word, and therefore they offer a coherent theory of both morphology and syntax. Hence, the collocation phenomena are considered like zero morphemes.
Moreover, a sharp distinction in the dictionary between the adpositional space, essentially made of closed morphemes, and the lexicon, made of open morphemes. Moving again from Tesnerian structural syntax, open morphemes always have a fundamental grammar character: stative (O), adjunctive (A, as stative modifiers), and verbal (I), circumstantial (E, as verbal modifiers). The Tesnierian approach is validated through Whorf’s research results comparing grammars of typologically distant NLs.
The second part shows that adgrams are computable, as they can be implemented with a strong, robust formalism. A concrete instance of the formal model of adgrams is given through the quasi-natural language Esperanto (QNL, Lyons), showing the linguistic viability of the model. The formal model should be used appropriately in an ad hoc epistemological scenario, called ‘the translation game’, designed as a Gedankenexperiment `a la Turing. A toy example is also given. In the third part the implementation is explained with all its details: the implementation of Esperanto is made in exactly 179 logic formulas, 56 of which are predicates. The formal model is promising to be generalised for any NLs, and how to do this was explained in various points of the third part. Finally, this dissertation shows that adgrams are a powerful NL grammar formalism which is at the same time cross-linguistic, cognitively grounded and formally robust and computationally sound
Il trattamento con rosuvastatina è associato ad una ridotta espressione dei recettori dell’angiotensina ii di tipo 1, ma non di tipo 2, nei monociti circolanti di soggetti diabetici.
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Environment, biodiversity and rare species: analysis of factors affecting bat conservation.
No full textTo assess the conservation status of rare and threatened species it is necessary to have background information about their distribution, and population size and trends. While all these information are available for well-studied taxa, there is a lack of knowledge for other poorly studied species. Among Mammals, bats and rodents represent the orders with the larger than average percentage of Data Deficient species and information scarcity is one of the greatest threats to bats. The understanding and identification of key resources for bats is of vital importance for their conservation.
In the present study we analysed the main ecological requirements of some rare bat species during breeding, mating and hibernation in Varese province (Lombardy, N Italy).
The analyis of space use, activity pattern and resource selection during the breeding period was focused on a small colony of females Geoffroy’s bat (Myotis emarginatus), roosting in the town hall of a small city, through monitoring and radiotracking. The timing of birth was in the first days of July and lactation lasted for less than a month. After weaning animals abandoned the roost and in september they reached swarming/wintering sites. Geoffroy’s bat females exploited a restricted area, covering short distances during dispersion and between summer and wintering sites. Animals showed large home ranges without a centre of activity (core area), concentrating their foraging behaviour on mountain foothills on the interface between meadows and woodlands. The favourite preys were spiders, which formed three-quarters of arthropod fragments in bat droppings, followed by beetles, planthoppers, moths and mosquitoes. Lactating females appeared to use foraging areas located closer to the breeding site, although they didn’t nurse often the youngsters during the night: this may be better explained as a energy-saving behaviour during a period of high energetic constraint. Nightly activity pattern was the same for lactating and non reproductive females; they both showed an unimodal pattern, spending most of the time on the wing foraging, with a mean of 7 hours per night.
The analysis of swarming and roosting behaviour during hibernation was centered on the analysis of bat activity and the characterisation of roosts in twelve underground sites of Campo dei Fiori Regional Park through monitoring. These caves were swarming and hibernating sites for six species, one of which was the Geoffroy’s bat, a species not known to swarm. Swarming activity started at the end of August, after a rapid decrease in mean environment temperature, and peaked in September. For all species sex ratio during swarming was skewed toward males (1:3), and this bias was even stronger for Myotis emarginatus (7% females). Bat activity was highest in caves positioned at high elevation, showing large entrances, low hydrological activity and exposition toward south-sothwest. The undergroud sites most used by animals were long and deep caves or short and shallow hollows: the former show a structure and hence microclimate suited for both swarming and hibernation, while the latter should be less fit for hibernation due to poor conditions of isolation from the athmosferic agents.
Underground sites are key resources for bats, in relation to breeding, mating and hibernation, and their uneven distribution on the territory makes them used by a large number of bats that gather from a vaste area. In addition, bats show a high fidelity to single roosting sites, therefore the loss or deterioration of underground sites can result
in a complete loss of suitable roosting place at a large scale, thus affecting different bat populations that could be subject to a decrease and a genetic deterioration.
The two most abundant species in the caves of Campo dei Fiori Regional Park (Myotis emarginatus and M. nattereri) showed a positive trend during the last 11 years. This increase may be due to the protection efforts that has been put in bat conservation, but a longer data set is required to discern natural population fluctuations from real trends.
The understanding of ecological requirements of rare and threatened species is imperative for the enhancement of effective conservation programs and the identification of features that affect bat choice of roosts is important to make predictions about the areas suitable for bat presence in order to concentrate our efforts in identifying new important roosting areas
The redshift dependence of the MBH–Mhost relation in quasars.
No full textThis Thesis is focused on the study of the evolution of the MBH–Lhost, Mhost relations
as a function of redshift. The aim is to probe whether (and how) the black hole – host galaxy relations evolve during Cosmic ages. This would contribute in constraining the possible formation histories of galaxies and in unveiling the mechanisms regulating the co-existence of black holes and galaxies.
The present study addresses the joint evolution of black holes and galaxies from an observational point of view. Our sample consists of 96 quasars with 0 < z < 3, half of which are radio loud (chapter 2). The stellar luminosities of the host galaxies are taken from imaging studies available in the literature, and from new observations led by our group (chapter 3). The stellar mass is derived from the host galaxy luminosity, under certain assumptions on
the star formation history of the galaxy (chapter 4). Spectroscopic determinations of the black hole masses are derived from the analysis of new data taken on purpose (chapters 3 and 5). The whole dataset is available in the appendix sections A and B. From the study of the MBH/Mhost ratio at low-z, where evolutionary effects are negligible, we infer some constraints
on the geometry of the broad line region. When moving to high redshift (z = 2−3),
we find that the MBH–Lhost relation is practically unchanged. On the other hand, because of the evolution of the stellar mass-to-light ratio, the MBH–Mhost relation shows a clear evolution, in the sense that, for a given host galaxy mass, black holes at high redshift are ∼ 8 times more massive than their low-z counter-parts. This trend cannot be explained in terms of selection effects, and is confirmed after relaxing some operative assumptions. Our results are compared to those of similar works available in the literature. Sketches of possible
interpretative scenarios are also discussed (chapter 6). Conclusions and future perspectives are presented in chapter 7.
The present work principally deals with the analyses and studies published in Decarli et
al. (2008a, on the broad line region geometry), Kotilainen et al. (2009, on the luminosity of quasar host galaxies at z > 2), Decarli et al. (2009b, on the spectroscopic dataset) and Decarli et al. (2009c, on the evolution of the BH–host galaxy relations). A complete list of my publications during the PhD is provided in appendix C
