Competing Conventions with Costly Information Acquisition

We consider an evolutionary model of social coordination in a 2 × 2 game where two groups of players prefer to coordinate on different actions. Players can pay a cost to learn their opponent’s group: if they pay it, they can condition their actions concerning the groups. We assess the stability of outcomes in the long run using stochastic stability analysis. We find that three elements matter for the equilibrium selection: the group size, the strength of preferences, and the information’s cost. If the cost is too high, players never learn the group of their opponents in the long run. If one group is stronger in preferences for its favorite action than the other, or its size is sufficiently large compared to the other group, every player plays that group’s favorite action. If both groups are strong enough in preferences, or if none of the groups’ sizes is large enough, players play their favorite actions and miscoordinate in inter-group interactions. Lower levels of the cost favor coordination. Indeed, when the cost is low, in inside-group interactions, players always coordinate on their favorite action, while in inter-group interactions, they coordinate on the favorite action of the group that is stronger in preferences or large enough

Palaeobiogeography and evolution of insular bovids: ecogeographic patterns of body mass variation and morphological changes

The study of the plants and animals that live on island has been a frequent key to understanding the processes of evolution that determine biotic diversity globally. Insular endemic mammals represent a special ground for the study of evolutionary mechanisms and speciation processes in response to the special characteristics of island environments. Endemic bovids are intriguing elements of insular faunas and offer an extensive and diversified sample for exploring patterns of insular evolution of large-sized mammals. This thesis provides the first comprehensive study on the evolution of extinct and living insular bovids, exploring the selective biotic and abiotic factors that influenced ecogeographic patterns of body mass variation and peculiar morphological changes (e.g., hypsodonty and low-gear locomotion) of these taxa. I show that the majority of island bovids, as large mammals, do follow the main prediction of the island rule, showing a body size reduction, and that ecological release and resource limitation are the main factors influencing body size evolution of these taxa. My results indicate that hypsodonty (increase in molar crown height), a quite common morphological trend in insular artiodactyls, is shared by the majority of insular bovids independently from the abrasiveness of the current diet. The evolution of this feature appear to result from an expansion of the dietary niche under resource limitation, although alternative, but complementary, hypotheses (e.g., increase in reproductive lifespan/longevity and changes in eating methods) cannot be excluded. The acquisition of a low-gear locomotion or the maintaining of a cursorial aptitude in insular bovids can be explained in the light of habitat selection (niche availability) and predatory pressure (ecological release) operating on each island. Finally, my results confirm the crucial role of time in isolation, with each of the above evolutionary phenomena becoming more developed for bovid populations with longer residence times on the islands. Another factor that needs to be mentioned is original bauplan, working as a constraint in the evolution of all the species in the study. By integrating research into the evolution of body mass variation and peculiar morphological changes exhibited by both extinct and extant bovids, this thesis documents patterns that have often been only hinted at previously, and identifies some that appear to be entirely new, providing new insights into the phenomena of the island syndrome and bovid evolution

The argali (Ovis ammon antiqua) from the Magliana area (Rome)

During the Middle Pleistocene, the subspecies was widespread from Georgia to Portugal, though it is scantily recorded in local faunal assemblages of Southern Europe. Its occurrence in a few Late Pleistocene sites needs to be confirmed. In Italy, the subspecies is recorded in the late Galerian fauna of Visogliano (MIS 13 - 10) as well as in the Magliana area, where an incomplete skull was found at the beginning of the last century. Although the precise location where this specimen was found is unknown, on the basis of the results of the geochemical analysis performed on a small amount of sediment, sampled from the filling of the inner cavities of the horn-cores, and considering the stratigraphy of the area, the hypothesis that the skull comes from the deposits of the PG4 sequence (MIS14 partim - MIS13) cannot be ruled out. This hypothetical remark would confirm the occurrence in Italy of the argali in late Galerian faunas. The dimensions of Ovis ammon antiqua from the Magliana area fit well within the range of variability of the larger specimens, likely males, found at La Caune de L’Arago (France) (MIS 14-12), from which the Italian specimen differs in having less twisted and more dorso-ventrally curved horn-cores

Causal explanations for the evolution of ‘low gear’ locomotion in insular ruminants

Aim: Mammals on islands often undergo remarkable evolutionary changes. The acquisition of ‘low gear’ locomotion, namely short and robust limb elements, has been typically associated with the island syndrome in large mammals and, especially, ruminants. Here we provide an investigative framework to examine biotic and abiotic selective factors hypothesized to influence evolution of this peculiar type of gait. Location: Islands worldwide. Taxon: Bovidae. Methods: We calculated response variables associated with ‘low gear’ locomotion in 21 extinct and extant insular bovids. We assembled data on the physiography of 11 islands and on life history and ecological traits of the focal taxa. We estimated 10 predictors (island area and four topographic indices, body mass, body size divergence, number of predators and competitors, large mammal richness) and used multiple regressions, regression trees, and random forests to assess their contextual importance. Results: The acquisition of ‘low gear’ locomotion generally happens on islands with a small number of competitors. However, the roughness of the island terrain appears to be also important, without being a main driver. Finally, although the most extreme cases of ‘low gear’ locomotion occurred on islands with no mammalian predators, our models show a non-significant relationship with this factor. Main conclusions: The evolution of ‘low gear’ locomotion in insular ruminants does not simply result from phyletic dwarfing and predatory release. Variation in morphological responses within Bovidae to ecological and topographic traits suggests, instead, a complex interplay of biotic and abiotic factors. Current understanding on the main drivers of species evolutionary pathways and biogeographic patterns are disproportionally based on few taxa, mainly vertebrates, and in some extreme cases (like this one) even on few species. Here we show how adding more data, even within the same taxonomic group, can challenge historically accepted macroevolutionary and macroecological concepts

Single-Walled Carbon Nanotubes as Enhancing Substrates for PNA-Based Amperometric Genosensors

A new amperometric sandwich-format genosensor has been implemented on single-walled carbon nanotubes screen printed electrodes (SWCNT-SPEs) and compared in terms of performance with analogous genoassays developed using the same methodology on non-nanostructured glassy carbon platforms (GC-SPE). The working principle of the genosensors is based on the covalent immobilization of Peptide Nucleic Acid (PNA) capture probes (CP) on the electrode surface, carried out through the carboxylic functions present on SWCNT-SPEs (carboxylated SWCNT) or electrochemically induced on GC-SPEs. The sequence of the CP was complementary to a 20-mer portion of the target DNA; a second biotin-tagged PNA signalling probe (SP), with sequence complementary to a different contiguous portion of the target DNA, was used to obtain a sandwich hybrid with an Alkaline Phosphatase-streptavidin conjugate (ALP-Strp). Comparison of the responses obtained from the SWCNT-SPEs with those produced from the non-nanostructured substrates evidenced the remarkable enhancement effect given by the nanostructured electrode platforms, achieved both in terms of loading capability of PNA probes and amplification of the electron transfer phenomena exploited for the signal transduction, giving rise to more than four-fold higher sensitivity when using SWCNT-SPEs. The nanostructured substrate allowed to reach limit of detection (LOD) of 71 pM and limit of quantitation (LOQ) of 256 pM, while the corresponding values obtained with GC-SPEs were 430 pM and 1.43 nM, respectively

Experimental pressure sensing and technology of piezoelectric microwave/RF MEMS filters

In this work, we analyze the pressure sensing of a thin film molybdenum/aluminumnitride/molybdenum (Mo/AlN/Mo) microwave/RF MEMS filter fabricated by a simple technology. After an experimental characterization in a frequency range between 1 and 36 GHz, we focused on the piezoelectric effect due to the stress properties of the piezoelectric AlN layer by applying forces by means of weights. Variations in the bandpass region of the microwave/RF filter are observed by proving high sensitivity also for low applied weights. We check by a properly designed three-dimensional (3D) finite-element method (FEM) tool the pressure-sensing property of the proposed device. Finally, we analyze the bad gap property of a chip with central defect around 40 GHz

A Peptide Nucleic Acid (PNA) Masking the miR-145-5p Binding Site of the 3'UTR of the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) mRNA Enhances CFTR Expression in Calu-3 Cells

Peptide nucleic acids (PNAs) have been demonstrated to be very useful tools for gene regulation at different levels and with different mechanisms of action. In the last few years the use of PNAs for targeting microRNAs (anti-miRNA PNAs) has provided impressive advancements. In particular, targeting of microRNAs involved in the repression of the expression of the cystic fibrosis transmembrane conductance regulator (CFTR) gene, which is defective in cystic fibrosis (CF), is a key step in the development of new types of treatment protocols. In addition to the anti-miRNA therapeutic strategy, inhibition of miRNA functions can be reached by masking the miRNA binding sites present within the 3'UTR region of the target mRNAs. The objective of this study was to design a PNA masking the binding site of the microRNA miR-145-5p present within the 3'UTR of the CFTR mRNA and to determine its activity in inhibiting miR-145-5p function, with particular focus on the expression of both CFTR mRNA and CFTR protein in Calu-3 cells. The results obtained support the concept that the PNA masking the miR-145-5p binding site of the CFTR mRNA is able to interfere with miR-145-5p biological functions, leading to both an increase of CFTR mRNA and CFTR protein content

Selective Functionalization with PNA of Silicon Nanowires on Silicon Oxide Substrates

Silicon nanowire chips can function as sensors for cancer DNA detection, whereby selective functionalization of the Si sensing areas over the surrounding silicon oxide would prevent loss of analyte and thus increase the sensitivity. The thermal hydrosilylation of unsaturated carbon-carbon bonds onto H-terminated Si has been studied here to selectively functionalize the Si nanowires with a monolayer of 1,8-nonadiyne. The silicon oxide areas, however, appeared to be functionalized as well. The selectivity toward the Si-H regions was increased by introducing an extra HF treatment after the 1,8-nonadiyne monolayer formation. This step (partly) removed the monolayer from the silicon oxide regions, whereas the Si-C bonds at the Si areas remained intact. The alkyne headgroups of immobilized 1,8-nonadiyne were functionalized with PNA probes by coupling azido-PNA and thiol-PNA by click chemistry and thiol-yne chemistry, respectively. Although both functionalization routes were successful, hybridization could only be detected on the samples with thiol-PNA. No fluorescence was observed when introducing dye-labeled noncomplementary DNA, which indicates specific DNA hybridization. These results open up the possibilities for creating Si nanowire-based DNA sensors with improved selectivity and sensitivity.</p