Viral epidemiology of the adult Apis Mellifera infested by the Varroa destructor mite

The ectoparasitic mite Varroa destructor has become one of the major worldwide threats for apiculture. Varroa destructor attacks the honey bee Apis mellifera weakening its host by sucking hemolymph. However, the damage to bee colonies is not strictly related to the parasitic action of the mite but it derives, above all, from its action as vector increasing the trasmission of many viral diseases such as acute paralysis (ABPV) and deformed wing viruses (DWV), that are considered among the main causes of CCD (Colony Collapse Disorder). In this work we discuss an SI model that describes how the presence of the mite affects the epidemiology of these viruses on adult bees. We characterize the system behavior, establishing that ultimately either only healthy bees survive, or the disease becomes endemic and mites are wiped out. Another dangerous alternative is the Varroa invasion scenario with the extinction of healthy bees. The final possible configuration is the coexistence equilibrium in which honey bees share their infected hive with mites. The analysis is in line with some observed facts in natural honey bee colonies. Namely, these diseases are endemic. Further, if the mite population is present, necessarily the viral infection occurs. The findings of this study indicate that a low horizontal transmission rate of the virus among honey bees in beehives will help in protecting bee colonies from Varroa infestation and viral epidemics

Low Level Laser Therapy as adjunctive support in implant dentistry: a reliable option?

Use of low level laser therapy (LLLT) in bone healing has been studied for years, and its application in implant dentistry is still a controversial topic due to the difficult assessment of its clinical efficacy. We report the application of LLLT as aid in the osseointegration in two patients undergone to implant surgery in the upper jaw. In one hemi-arch the LLLT was applied and the other one was used as control. The assessment of the bone area surrounding the fixtures was performed by means of cone beam compute tomography and the area of bone-implants contact was measured by means of InVesalius® software. The radiological findings support the idea of considering the laser biostimulation as an adjunctive aid in implant surgery

Progetto strutturale e certificazione energetica di un edificio residenziale a Viareggio

La presente tesi di laurea tratta la progettazione di un edificio ad uso residenziale ubicato nella città di Viareggio. Nella prima parte della trattazione, è stata condotta un’analisi dell’area di interesse. La progettazione strutturale, è stata condotta con particolare attenzione allo studio dell’azione sismica. Creato un modello tridimensionale, con il programma di calcolo “sap 2000 V10” si sono ricavate le sollecitazioni effettive sulle membrature e condotte le relative verifiche sia per la struttura in acciaio che per quella in cemento armato procedendo poi allo studio dei collegamenti. E’ stata condotta un’analisi dell’edificio in ambito energetico con la finalità di realizzare una costruzione a basso consumo e proporre una sua classificazione energetica. Sono stati condotti studi circa il comportamento termo-igrometrico dell’involucro dell’edificio. Per ogni alloggio si è provveduto al calcolo dell’indice di prestazione energetica per la climatizzazione invernale nonché dell’indice di prestazione energetica per la produzione di acqua calda sanitaria. E’ stata posta attenzione all’utilizzo di fonti rinnovabili di energia determinando la superficie di pannelli solari termici necessari al soddisfacimento di almeno il 50% del fabbisogno di acqua calda sanitaria. Al fine di valutare l’indice di prestazione energetica globale EPgl degli appartamenti, necessario per determinare la loro classe energetica, sono stati sommati i due indici precedentemente trovati; le unità abitative sono appartenenti alla classe A+

A particle model reproducing the effect of a conflicting flight information on the honeybee swarm guidance

The honeybee swarming process is steered by few scout individuals, which are the unique informed on the location of the target destination. Theoretical and experimental results suggest that bee coordinated flight arises from visual signals. However, how the information is passed within the population is still debated. Moreover, it has been observed that honeybees are highly sensitive to conflicting directional information. In fact, swarms exposed to fast-moving bees headed in the wrong direction show clear signs of disrupted guidance. In this respect, we here present a discrete mathematical model to investigate different hypotheses on the behaviour both of informed and uninformed bees. In this perspective, numerical realizations, specifically designed to mimic selected experiments, reveal that only one combination of the considered assumptions is able to reproduce the empirical outcomes, resulting thereby the most reliable mechanism underlying the swarm dynamics according to the proposed approach. Specifically, this study suggests that (i) leaders indicate the right flight direction by repeatedly streaking at high speed pointing towards the target and then slowly coming back to the trailing edge of the bee cloud; and (ii) uninformed bees, in turn, gather the route information by adapting their movement to all the bees sufficiently close to their position

An agent-based approach for modelling collective dynamics in animal groups distinguishing individual speed and orientation: Particle model for animal group dynamics

Collective dynamics in animal groups is a challenging theme for the model- ling community, being treated with a wide range of approaches. This topic is here tackled by a discrete model. Entering in more details, each agent, rep- resented by a material point, is assumed to move following a first-order Newtonian law, which distinguishes speed and orientation. In particular, the latter results from the balance of a given set of behavioural stimuli, each of them defined by a direction and a weight, that quantifies its relative importance. A constraint on the sum of the weights then avoids implausible simultaneous maximization/minimization of all movement traits. Our framework is based on a minimal set of rules and parameters and is able to capture and classify a number of collective group dynamics emerging from different individual preferred behaviour, which possibly includes attrac- tive, repulsive and alignment stimuli. In the case of a system of animals subjected only to the first two behavioural inputs, we also show how analytical arguments allow us to a priori relate the equilibrium interparticle spacing to critical model coefficients. Our approach is then extended to account for the presence of predators with different hunting strategies, which impact on the behaviour of a prey population. Hints for model refinement and applications are finally given in the conclusive part of the article

A particle model analyzing the behavioral rules underlying the collective flight of a bee swarm towards the new nest

The swarming of a bee colony is guided by a small group of scout individuals, which are informed of the target destination (the new nest). However, little is known on the underlying mechanisms, i.e. on how the information is passed within the population. In this respect, we here present a discrete mathematical model to investigate these aspects. In particular, each bee, represented by a material point, is assigned its status within the colony and set to move according to individual strategies and social interactions. More specifically, we propose alternative assumptions on the flight synchronization mechanism of uninformed individuals and on the characteristic dynamics of the scout insects. Numerical realizations then point out the combinations of behavioural hypotheses resulting in collective productive movement. An analysis of the role of the scout bee percentage and of the phenomenology of the swarm in domains with structural elements is finally performed

La Tassazione della Digital Economy nell'Action Plan BEPS n.1 dell'OCSE e nella "Dichiarazione di Bari" del G7

Il libro prende le mosse da un\u2019iniziativa promossa dall\u2019Associazione Italiana dei Professori di Diritto Tributario (AIPDT), che ha promosso la ricerca sul tema \u201cLe nuove forme di tassazione della Digital Economy\u201d. La ricerca, di cui \ue8 coordinatore Lorenzo Del Federico e a cui hanno aderito prestigiosi studiosi della materia, elabora proposte normative su singoli profili della tassazione delle attivit\ue0 digitali, che siano espressione del punto di vista italiano ma nel contempo tengano conto del quadro europeo e della compatibilit\ue0 con i principi di tassazione Ue e internazionali

La Tassazione della Digital Economy nell'Action Plan BEPS n.1 dell'OCSE e nella "Dichiarazione di Bari" del G7

Il libro prende le mosse da un\u2019iniziativa promossa dall\u2019Associazione Italiana dei Professori di Diritto Tributario (AIPDT), che ha promosso la ricerca sul tema \u201cLe nuove forme di tassazione della Digital Economy\u201d. La ricerca, di cui \ue8 coordinatore Lorenzo Del Federico e a cui hanno aderito prestigiosi studiosi della materia, elabora proposte normative su singoli profili della tassazione delle attivit\ue0 digitali, che siano espressione del punto di vista italiano ma nel contempo tengano conto del quadro europeo e della compatibilit\ue0 con i principi di tassazione Ue e internazionali

Categorie del Diritto Tributario e Nuove Frontiere dell'Economia Digitale

La ricerca, con approccio interdisciplinare, intende proporre spunti di riflessione sui complessi, e cos\uec attuali, temi costantemente sollevati dalla peculiarit\ue0 delle nuove realt\ue0 economiche, attraverso lo studio delle criticit\ue0 - e delle possibili soluzioni - che concernono la tassazione dell'economia digitale, intesa non tanto come settore distinto rispetto al resto dell'economia, bens\uec come generale fenomeno di digitalizzazione che tocca diversi aspetti delle attivit\ue0 economiche