A new model for estimating the probability of information spreading with opinion leaders

In this paper we analyze some issues related to the general problem of informa- tion spreading among individuals, where suitable assumptions on the information exchange are considered. In particular, starting from the scheme proposed in Galam (2003), which is based on a majority rule to treat the individuals’ interaction, we define and introduce special indi- viduals who play a key role in the information spreading. The latter will be addressed as opinion leaders, and have the special feature of strongly interfering with the process based on the majority rule. We consider a new model, where opinion leaders are introduced as special agents, and study its specific properties which significantly recast some conclusions worth for the model in Galam (2003). Finally, we provide some results concerning the dynamics of the model

A Modified Galam's Model

In this paper we analyze the stochastic model proposed by Galam in [2], for information spreading in a `word-of-mouth' process among agents, based on a majority rule. Using the communications rules among agents defined in [2], we first perform simulations of the `word-of-mouth' process and compare the results with the theoretical values predicted by Galam's model. Since some dissimilarities arise in particular when a small number of agents is considered, we suggest some enhancements by introducing a new parameter dependent model. We propose a modified Galam's scheme which is asymptotically coincident with the original model in [2]. Furthermore, for relatively small values of the parameter, we provide a numerical experience proving that the modified model often outperforms the original one, in terms of efficiency

Synthesis of Atropisomeric Hydrazides by One-Pot Sequential Enantio- and Diastereoselective Catalysis

The first catalytic enantioselective and diastereoselective synthesis of atropisomeric hydrazides was achieved using a sequential catalysis protocol. This strategy is based on a one-pot sequence of two organocatalytic cycles featuring the enamine amination of branched aldehydes followed by nitrogen alkylation under phase-transfer conditions. The resulting axially chiral hydrazides were obtained directly from commercially available reagents in high yields and with good stereocontrol. The permutation of organocatalysts allowed easy access to all stereoisomers, enabling a stereodivergent approach to enantioenriched atropisomeric hydrazides

Selfie acustiche con il progetto selfear: un'applicazione mobile per l'acquisizione a basso costo di pinna-related transfer function

Le esperienze di realta virtuale e aumentata stanno riscontrando una grande diffusione e le tecnologie per la spazializzazione del suono in cuffia saranno fondamentali per la diffusione di scenari applicativi immersivi in supporti mobile. Questo articolo affronta le problematiche legate alla acquisizione di head-related tranfer function (HRTF) con dispositivi a basso costo, accessibili a chiunque, in qualsiasi luogo e che forniscano delle misurazioni fruibili in tempi brevi. In particolare la soluzione proposta denominata "the SelfEar project" si focalizza sull'acquisizione delle trasformazioni spettrali ad opera dell'orecchio esterno contenute nella pinna-related transfer function (PRTF); l'utente viene guidato nella misurazione di HRTF in ambiente non anecoico attraverso una procedura auto-regolabile. Le informazioni acustiche sono infatti acquisite tramite un headset per la realt`a acustica aumentata che include un set di microfoni posizionati in prossimit\ue0 dei canali uditivi dell'ascoltatore. Proponiamo una sessione di misurazione con l'obiettivo di acquisire le caratteristiche spettrali della PRTF di un manichino KEMAR, confrontandoli con i risultati che si otterrebbero con una procedura in ambiente anecoico. In entrambi i casi i risultati dipendono fortemente dalla posizione dei microfoni, senza considerare in questo scenario il problema legato ai movimenti di un eventuale soggetto umano. Considerando la qualit\ue0 generale e la variabilit\ue0 dei risultati, cos\uec come le risorse totali necessarie, il progetto SelfEar propone una promettente soluzione per una procedura a basso costo di acquisizione di PRTF, e pi\uf9 in generale di HRTF

The repeatability of cognitive performance:A meta-analysis

This is the author accepted manuscript. The final version is available from The Royal Society via the DOI in this record.Behavioural and cognitive processes play important roles in mediating an individual's interactions with its environment. Yet, while there is a vast literature on repeatable individual differences in behaviour, relatively little is known about the repeatability of cognitive performance. To further our understanding of the evolution of cognition, we gathered 44 studies on individual performance of 25 species across six animal classes and used meta-analysis to assess whether cognitive performance is repeatable. We compared repeatability (R) in performance (1) on the same task presented at different times (temporal repeatability), and (2) on different tasks that measured the same putative cognitive ability (contextual repeatability). We also addressed whether R estimates were influenced by seven extrinsic factors (moderators): type of cognitive performance measurement, type of cognitive task, delay between tests, origin of the subjects, experimental context, taxonomic class and publication status. We found support for both temporal and contextual repeatability of cognitive performance, with mean R estimates ranging between 0.15 and 0.28. Repeatability estimates were mostly influenced by the type of cognitive performance measures and publication status. Our findings highlight the widespread occurrence of consistent inter-individual variation in cognition across a range of taxa which, like behaviour, may be associated with fitness outcomes.PKYC is supported by Japan Society for the Promotion of Science (PE1801); JOvH was funded by an ERC consolidator grant (616474). MC and this research was supported by a grant from the Human Frontier Science Program to ASC and JM-F (RGP0006/2015)

Excretion patterns of coccidian oocysts and nematode eggs during the reproductive season in Northern Bald Ibis (Geronticus eremita)

Individual reproductive success largely depends on the ability to optimize behaviour, immune function and the physiological stress response. We have investigated correlations between behaviour, faecal steroid metabolites, immune parameters, parasite excretion patterns and reproductive output in a critically endangered avian species, the Northern Bald Ibis (Geronticus eremita). In particular, we related haematocrit, heterophil/lymphocyte ratio, excreted immune-reactive corticosterone metabolites and social behaviour with parasite excretion and two individual fitness parameters, namely, number of eggs laid and number of fledglings. We found that the frequency of excretion of parasites’ oocysts and eggs tended to increase with ambient temperature. Paired individuals excreted significantly more samples containing nematode eggs than unpaired ones. The excretion of nematode eggs was also significantly more frequent in females than in males. Individuals with a high proportion of droppings containing coccidian oocysts were more often preened by their partners than individuals with lower excretion rates. We observed that the more eggs an individual incubated and the fewer offspring fledged, the higher the rates of excreted samples containing coccidian oocysts. Our results confirm that social behaviour, physiology and parasite burden are linked in a complex and context-dependent manner. They also contribute background information supporting future conservation programmes dealing with this critically endangered species

A modified Galam’s model for word-of-mouth information exchange

In this paper we analyze the stochastic model proposed by Galam in [S. Galam, Modelling rumors: The no plane Pentagon French hoax case, Physica A 320 (2003), 571-580], for information spreading in a `word-of-mouth' process among agents, based on a majority rule. Using the communications rules among agents defined in the above reference, we first perform simulations of the `word-of-mouth' process and compare the results with the theoretical values predicted by Galam's model. Some dissimilarities arise in particular when a small number of agents is considered. We find motivations for these dissimilarities and suggest some enhancements by introducing a new parameter dependent model. We propose a modified Galam's scheme which is asymptotically coincident with the original model in the above reference. Furthermore, for relatively small values of the parameter, we provide a numerical experience proving that the modified model often outperforms the original one