A Comparative Study and Analysis of Conversational Search Algorithms to Improve their Reproducibility

openConversational Search is a field of Information Retrieval that is steadily gaining popularity in recent years. A conversational retrieval system aims to engage with the users in conversations using natural language. In this work, we studied, implemented and compared a total of eleven state-of-the-art algorithms and strategies for conversational search. Additionally, we developed a conversational retrieval framework focused on modularity, extensibility and reproducibility, that we used to test said algorithms. The top-performant method we tested, Context Query, obtained an nDCG@3 of 0.43, beating more complex methods, like the ones based on coreference resolution or Large Language models (i.e., BERT), by at least 10%. Concerning the reproducibility aspect, we’ve been able to reach comparable results on several methods for which we had a suitable comparing value.Conversational Search is a field of Information Retrieval that is steadily gaining popularity in recent years. A conversational retrieval system aims to engage with the users in conversations using natural language. In this work, we studied, implemented and compared a total of eleven state-of-the-art algorithms and strategies for conversational search. Additionally, we developed a conversational retrieval framework focused on modularity, extensibility and reproducibility, that we used to test said algorithms. The top-performant method we tested, Context Query, obtained an nDCG@3 of 0.43, beating more complex methods, like the ones based on coreference resolution or Large Language models (i.e., BERT), by at least 10%. Concerning the reproducibility aspect, we’ve been able to reach comparable results on several methods for which we had a suitable comparing value

Functional characterization of AtTPK3 potassium channel of Arabidopsis thaliana

My Ph.D. project has focused on the characterization of TPK3, a putative channel selective for potassium (K+) with a predicted chloroplast localization in higher plants, from biochemical, physiological and electrophysiological point of view. This protein belongs to the TPK channel family (from Tandem-Pore K+ channels) and displays amino acid sequence homology with another K+ channel studied in our laboratory, called SynK (Zanetti et al., 2010). SynK shows thylakoid localization in Cyanobacteria. The SynK channel has been shown to be critical for photosynthetic performances in Cyanobacteria, given the photosensitive phenotype displayed by the mutants lacking the SynK protein. Given the homology, we hypothesized that similarly, TPK3 might be involved in the regulation of photosynthetic processes in higher plants. So far, no information is available about the properties of TPK3, nor about its physiological roles, neither about its possible involvement in photosynthesis; the work presented in this thesis had the aim of clarifying some important aspects of the functions of TPK3. Following subcellular localization studies carried out using biochemistry and confocal microscopy techniques, the TPK3 channel was expressed in E. coli cells for subsequent electrophysiological characterization in a planar lipid bilayer setup in order to prove its function as K+ channel. The unavailability of commercial mutants for tpk3 gene required setting up of a silencing procedure via RNA interference of the messenger for the protein, in order to analyze the possible physiological roles of TPK3. The resulting silenced plants have been studied under different growth conditions to determine changes in physiology of the plants including their photosynthetic parameters. In parallel with the TPK3 project, the most important part of my Ph.D., I also followed two other major areas of research: one concerning the study of the functions of two members of plant Glutamate Receptors (GluRs) and the other one concerning the characterization of the plant homologous of the recently identified MCU (Mitochondrial Calcium Uniporter) of mammals. This thesis also includes a manuscript (Checchetto et al., 2012) to which I contributed with the heterologous expression of a calcium-activated K+ channel, SynCaK, of Cyanobacteria

The Mainstreaming of NBS in the SECAP of San Don\ue0 di Piave: The LIFE Master Adapt Methodology

Climate change is a global phenomenon that poses local risks to sectors across society and the economy. All these growing risks have led the Municipality of San Don\ue0 di Piave\u2014located within the Metropolitan City of Venice (CMVe)\u2014to strengthen, over the years, its commitment to the adaptation to climate change in its plans and policies. Nature-based solutions can offer a perfect example of sustainable solutions to cope with climate change mitigation and adaptation challenges. In this context, thanks to the support of the LIFE Master Adapt project, San Don\ue0 di Piave, applying its methodologies and creating new territorial information, was able to insert, within its Action Plan for Sustainable Energy and Climate (SECAP), important and structural Nature-Based Solutions (NBSs) for the entire municipal area. This experience demonstrates how this process of mainstreaming adaptation actions and NBSs is possible at all levels of government of the territory. It also highlights the virtuosity of replicability in other contexts of the CMVe and the transition from theoretical concepts to concrete actions (NBSs) for adaptation into existing plans. This process happened with a climate-proof modification of the existing planning attitude, whether mandatory or voluntary

Svantaggiato, interno, montano: Italia laboratorio sperimentale.

At morphological and socioeconomic level, the Italian territory can be defined as predominantly disadvantaged, internal and mountain. Historically, the combination of these three conditions has created a variegated cultural system. On the other hand, it has curbed the dominant development of the market economy, safeguarding and protecting biodiversity bubbles, cultural and social wealth. This research, through the collection of good practices, defines the Italian territory as an experimental laboratory. This recalls the Italy\u2019s design culture - artisanal and scientific, technical and informal, for attempts and practices \u2013 that is laborious, innovative, creative, minute and widespread. The research investigates the Italian condition of the inner areas and the territories of the margin, and wants to make a theoretical, methodological and applicative contribution to the debate on the depopulation of the territory and the abandonment of heritage. The research builds a theoretical knowledge framework, a methodology for the study of the territory and the definition of a strategic program of local development

Horizontal Stratified Air–Foam–Water Flows: Preliminary Modelling Attempts with OLGA

Water accumulation is a major problem in the flow assurance of gas pipelines. To limit liquid loading issues, deliquification by means of surfactant injection is a promising alternative to the consolidated mechanical methods. However, the macroscopic behavior of foam pipe flow in the presence of other phases has barely been explored. The goal of this work was to propose an approach to simulate air–water–foam flows in horizontal pipes using OLGA by Schlumberger, an industry standard tool for the transient simulation of multiphase flow. The simulation results were compared with experimental data for 60 mm and 30 mm ID (Inner Diameter) horizontal pipelines. Preliminary validation for two-phase air–water flow was carried out, which showed that correct flow pattern recognition is essential to accurately reproduce the experimental data. Then, stratified air–foam–water flows were investigated, assuming different models for the foam local velocity distribution. Foam rheology was considered through the Herschel–Bulkley model with the yield stress varying in time due to foam decay. The results showed good agreement for a uniform velocity profile and fresh foam properties in the case of the 60 mm ID pipeline, whereas for the 30 mm ID, which was characterized by significantly higher velocities, a linear velocity profile and 2000 s foam aging provided the best agreement. In both cases, the pressure gradient was overestimated, and the mean absolute prediction error ranged from about 5% to 30%

Transcriptional variation of sensory-related genes in natural populations of Aedes albopictus

BACKGROUND: The Asian tiger mosquito, Aedes albopictus, is a highly dangerous invasive vector of numerous medically important arboviruses including dengue, chikungunya and Zika. In four decades it has spread from tropical Southeast Asia to many parts of the world in both tropical and temperate climes. The rapid invasion process of this mosquito is supported by its high ecological and genetic plasticity across different life history traits. Our aim was to investigate whether wild populations, both native and adventive, also display transcriptional genetic variability for functions that may impact their biology, behaviour and ability to transmit arboviruses, such as sensory perception. RESULTS: Antennal transcriptome data were derived from mosquitoes from a native population from Ban Rai, Thailand and from three adventive Mediterranean populations: Athens, Greece and Arco and Trento from Italy. Clear inter-population differential transcriptional activity was observed in different gene categories related to sound perception, olfaction and viral infection. The greatest differences were detected between the native Thai and the Mediterranean populations. The two Italian populations were the most similar. Nearly one million quality filtered SNP loci were identified. CONCLUSION: The ability to express this great inter-population transcriptional variability highlights, at the functional level, the remarkable genetic flexibility of this mosquito species. We can hypothesize that the differential expression of genes, including those involved in sensory perception, in different populations may enable Ae. albopictus to exploit different environments and hosts, thus contributing to its status as a global vector of arboviruses of public health importance. The large number of SNP loci present in these transcripts represents a useful addition to the arsenal of high-resolution molecular markers and a resource that can be used to detect selective pressure and adaptive changes that may have occurred during the colonization process

Dissecting stimulus-specific Ca2+ signals in amyloplasts and chloroplasts of Arabidopsis thaliana cell suspension cultures

Calcium is used by plants as an intracellular messenger in the detection of and response to a plethora of environmental stimuli and contributes to a fine-tuned internal regulation. Interest in the role of different subcellular compartments in Ca(2+) homeostasis and signalling has been growing in recent years. This work has evaluated the potential participation of non-green plastids and chloroplasts in the plant Ca(2+) signalling network using heterotrophic and autotrophic cell suspension cultures from Arabidopsis thaliana plant lines stably expressing the bioluminescent Ca(2+) reporter aequorin targeted to the plastid stroma. Our results indicate that both amyloplasts and chloroplasts are involved in transient Ca(2+) increases in the plastid stroma induced by several environmental stimuli, suggesting that these two functional types of plastids are endowed with similar mechanisms for handling Ca(2+). A comparison of the Ca(2+) trace kinetics recorded in parallel in the plastid stroma, the surface of the outer membrane of the plastid envelope, and the cytosol indicated that plastids play an essential role in switching off different cytosolic Ca(2+) signals. Interestingly, a transient stromal Ca(2+) signal in response to the light-to-dark transition was observed in chloroplasts, but not amyloplasts. Moreover, significant differences in the amplitude of specific plastidial Ca(2+) changes emerged when the photosynthetic metabolism of chloroplasts was reactivated by light. In summary, our work highlights differences between non-green plastids and chloroplasts in terms of Ca(2+) dynamics in response to environmental stimuli

Convective condensation of R134a and R1234ze(E) inside microfin tube

Environmental concerns are forcing the replacement of the commonly used refrigerants and finding new fluids is a top priority. The hydro-fluoro-olefin (HFO) R1234ze(E), because of its smaller global warming potential (GWP) and shorter atmospheric lifetime, replaced R134a. Accordingly, for HVAC systems design, a detailed knowledge of the thermo-fluid-dynamic characteristics of the fluids and reliable predictive models are required. To improve the understanding, R134a and R1234ze(E) were employed in convective condensation experiments (saturation temperature Tsat = 35°C, mean quality xm = 0.1~0.9, quality changes Δx = 0.05~0.6, mass flux G = 43~444 kg·m-2s-1) inside a microfin tube (outer diameter D = 9.52 mm, fin number n = 60, fin height H = 0.2 mm). The results were used for two goals: the former is the comparison of the heat transfer features of the two fluids, while the latter aims at testing the performance of prediction models available in the open literature. At the saturation temperature T = 35°C, the two fluids show small differences in the thermal properties so that, as expected, the experiments highlighted a very similar behavior in the typical operating conditions of HVAC systems. In fact, for all the operating conditions marginal differences were observed in the pressure drop, the heat transfer coefficient and the flow pattern maps. The issue of prediction reliability, however, is still open. Actually, not all the models achieving good results for R134a show the same performance for R1234ze(E), especially for the pressure drop

Transcriptional variation of sensory-related genes in natural populations of Aedes albopictus

BACKGROUND: The Asian tiger mosquito, Aedes albopictus, is a highly dangerous invasive vector of numerous medically important arboviruses including dengue, chikungunya and Zika. In four decades it has spread from tropical Southeast Asia to many parts of the world in both tropical and temperate climes. The rapid invasion process of this mosquito is supported by its high ecological and genetic plasticity across different life history traits. Our aim was to investigate whether wild populations, both native and adventive, also display transcriptional genetic variability for functions that may impact their biology, behaviour and ability to transmit arboviruses, such as sensory perception. RESULTS: Antennal transcriptome data were derived from mosquitoes from a native population from Ban Rai, Thailand and from three adventive Mediterranean populations: Athens, Greece and Arco and Trento from Italy. Clear inter-population differential transcriptional activity was observed in different gene categories related to sound perception, olfaction and viral infection. The greatest differences were detected between the native Thai and the Mediterranean populations. The two Italian populations were the most similar. Nearly one million quality filtered SNP loci were identified. CONCLUSION: The ability to express this great inter-population transcriptional variability highlights, at the functional level, the remarkable genetic flexibility of this mosquito species. We can hypothesize that the differential expression of genes, including those involved in sensory perception, in different populations may enable Ae. albopictus to exploit different environments and hosts, thus contributing to its status as a global vector of arboviruses of public health importance. The large number of SNP loci present in these transcripts represents a useful addition to the arsenal of high-resolution molecular markers and a resource that can be used to detect selective pressure and adaptive changes that may have occurred during the colonization process

Viviparity and habitat restrictions may influence the evolution of male reproductive genes in tsetse fly (Glossina) species

11openInternationalInternational coauthor/editorBackground Glossina species (tsetse flies), the sole vectors of African trypanosomes, maintained along their long evolutionary history a unique reproductive strategy, adenotrophic viviparity. Viviparity reduces their reproductive rate and, as such, imposes strong selective pressures on males for reproductive success. These species live in sub-Saharan Africa, where the distributions of the main sub-genera Fusca, Morsitans, and Palpalis are restricted to forest, savannah, and riverine habitats, respectively. Here we aim at identifying the evolutionary patterns of the male reproductive genes of six species belonging to these three main sub-genera. We then interpreted the different patterns we found across the species in the light of viviparity and the specific habitat restrictions, which are known to shape reproductive behavior. Results We used a comparative genomic approach to build consensus evolutionary trees that portray the selective pressure acting on the male reproductive genes in these lineages. Such trees reflect the long and divergent demographic history that led to an allopatric distribution of the Fusca, Morsitans, and Palpalis species groups. A dataset of over 1700 male reproductive genes remained conserved over the long evolutionary time scale (estimated at 26.7 million years) across the genomes of the six species. We suggest that this conservation may result from strong functional selective pressure on the male imposed by viviparity. It is noteworthy that more than half of these conserved genes are novel sequences that are unique to the Glossina genus and are candidates for selection in the different lineages. Conclusions Tsetse flies represent a model to interpret the evolution and differentiation of male reproductive biology under different, but complementary, perspectives. In the light of viviparity, we must take into account that these genes are constrained by a post-fertilization arena for genomic conflicts created by viviparity and absent in ovipositing species. This constraint implies a continuous antagonistic co-evolution between the parental genomes, thus accelerating inter-population post-zygotic isolation and, ultimately, favoring speciation. Ecological restrictions that affect reproductive behavior may further shape such antagonistic co-evolution.openSavini, Grazia; Scolari, Francesca; Ometto, Lino; Rota-Stabelli, Omar; Carraretto, Davide; Gomulski, Ludvik M.; Gasperi, Giuliano; Abd-Alla, Adly M. M.; Aksoy, Serap; Attardo, Geoffrey M.; Malacrida, Anna R.Savini, G.; Scolari, F.; Ometto, L.; Rota-Stabelli, O.; Carraretto, D.; Gomulski, L.M.; Gasperi, G.; Abd-Alla, A.M.M.; Aksoy, S.; Attardo, G.M.; Malacrida, A.R