Phase Transitions in Finite Systems using Information Theory

(abridged) In this paper, we present the issues we consider as essential as far as the statistical mechanics of finite systems is concerned. In particular, we emphasis our present understanding of phase transitions in the framework of information theory. Information theory provides a thermodynamically-consistent treatment of finite, open, transient and expanding systems which are difficult problems in approaches using standard statistical ensembles. As an example, we analyze is the problem of boundary conditions, which in the framework of information theory must also be treated statistically. We recall that out of the thermodynamical limit the different ensembles are not equivalent and in particular they may lead to dramatically different equation of states, in the region of a first order phase transition. We recall the recent progresses achieved in the understanding of first-order phase transition in finite systems: the equivalence between the Yang-Lee theorem and the occurrence of bimodalities in the intensive ensemble and the presence of inverted curvatures of the thermodynamic potential of the associated extensive ensemble.Comment: To be published in AIP Conference Proceeding

Covid-19: come la pandemia ha aumentato la food insecurity e alterato il regime alimentare nelle famiglie italiane

Background - The Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) pandemic and subsequent containment measures are causing a worldwide increase in food insecurity (FI). Food insecurity has been related to a number of negative health implications, particularly for the most vulnerable population, including children and adolescents. Aim - To investigate the effects on FI during the lockdown in Italy and the changes in eating habits and body weight in the paediatric population 6 months after the beginning of the pandemic. Materials and Methods - An online anonymous cross-sectional survey was elaborated and proposed to the parents of children < 18 years old. Results - 8.3% reported that their families were at risk of FI before the outbreak of SARS-CoV-2 pandemic. This percentage dramatically doubled after the pandemic began. Moreover, 27.3% of the parents reported that their children were eating more, with a concomitant increase in "junk food" consumption. About one third of respondents declared an increase in children's weight, while weight loss were uncommon and prevailed among adolescents. It was observed that parents' higher age, higher parents' school grade and working parents were protective factors against FI. Conclusion - Since the SARS-CoV-2 pandemic is requiring restrictions again, it is crucial that health care and social protection programmes take into account concepts of equity and sustainability to ensure adequate food and nutrition security for everyone

The newly discovered Odyssea Drift (Ross Sea): preliminary results

The Hillary Canyon is one of the main conduits for dense shelf water forming in the Ross Sea, over-flowing the shelf edge and transforming into the Antarctic Bottom Water (AABW). The main changes in past ocean circulation are recorded in the adjacent sediment drift. A wealth of data was acquired on the drift west of the Hillary Canyon during the 2017 OGS Explora expedition, which included the PNRA ODYSSEA and EUROFLEETS ANTSSS projects. The multi-disciplinary dataset acquired includes: single channel seismics, sub-bottom profiling, multibeam bathymetry, gravity and box cores, XBT launching, water sampling, CTD, L-ADCP, ADCP-VM, turbidity and florescence profiling. The sediment drift, which we named Odyssea Drift, is elongated in the NNE direction with dimensions of several tens of km. Prominent landslide scars and a giant landslide deposit, over 70 ms thick and spanning 200 km2, are visible on the drift. The sediment cores evidence well-developed cross beddings suggesting the effect of vigorous bottom currents. The oceanographic data show a ⇠200 m thick layer, near the bottom, with AABW characteristics (potential temperature &lt; 0 C). The deeper layer displays also a strong velocity, mainly flowing along the isobaths. The energetic mixing between the along slope currents, mainly CDW, and the RSBW coming from the basin interior increase the turbidity of the bottom boundary layer. Our results will be merged with those obtained from the 2018 IODP drilling expedition 374 to develop a conceptual model of sediment deposition relating to marine-based ice sheet and oceanic processes along the Ross Sea continental margin occurring through the Neogene and Quaternary

A green approach to mesoporous silica particles synthesis by sol-gel chemistry

Mesoporous silica materials have a wide variety of applications in different sectors depending on their characteristic porosity, particle dimensions and functionalization. They are used as heterogeneous catalyst agents in industrial synthesis, stationary phase in chromatography or in biomedical applications as drug delivery systems. Consequently a significant number of studies have focused on the development of preparation methods that allow the regulation of the pore size and pore morphology of the silica. This thesis work, conducted at UCC (University College Cork, Ireland), aims to find a “greener” path than the one traditionally used to synthesize good quality mesoporous silica particles. It is a preliminary work whose purpose is to determine if it can be considered viable to start further systematic research in this direction. Nowadays it is impossible to ignore the need of an environmentally sustainable approach towards chemical synthesis and processes design. Green Chemistry and its Twelve Principles are central to the development of the mesoporous silica material preparation procedure utilized within this research. A modified Stöber sol-gel method of synthesis was chosen for its intrinsically green features: it is a batch process, the reaction takes place at room temperature and one of the main solvents is water. This study focuses on changing those aspects of the “standard” procedure which are not so environmentally friendly: the second solvent (alcohol), the surfactant (most commonly CTAB) and the post synthesis hydrothermal treatment. In particular Sodium Alginate, a polysaccharide extracted from the cell wall of brown seaweed, is the surfactant of choice. Until now no works have been reported on the use of alginate as a direct anionic surfactant template. Characterization of obtained silica particles was performed employing N2 sorption for information about porosity and SEM and TEM imaging to evaluate particles aggregation, aspect and size

High resolution study of Dinocyst assemblages in Sapropel S1, S3 and S5: preliminary report.

The Eastern Mediterranean late Neogene sedimentary record is characterized by the widespread and distinctly periodical occurrence of organic carbon-rich layers, called sapropels. The deposition of sapropels is related to significant changes in climate, in the pattern of water circulation and in the biogeochemical cycles. The primary cause triggering the formation of sapropels has been debated ever since their discovery: productivity in the surface waters and organic matter preservation at the sea-floor due to hypoxia or anoxia have been indicated as the two major contributing factors operating either separately or combined. Moreover, each and every sapropel seems to have its own peculiar feature, likely attributed to the different climate forcing and the different response of productivity and preservation to the water column parameters. Here we present preliminary data from core M25/4 12, located in the Ionian Sea, containing a continuous record of the sapropels deposited in the last 330 ka (S1 to S10, excluding S2). We analysed the dinoflagellate cyst assemblages in sapropels S1 (˜10 ka BP), S3 (˜80 ka BP) and S5 (˜125 ka BP) at a multi-centennial time resolution to get insights into the climatic and oceanographical features leading to their deposition and the role of productivity and preservation. Dinocysts usually show an increase in productivity of surface water at or slightly before sapropel deposition starts, but different productivity patterns within the sapropels. Different dominant species in sapropels S1, S3 and S5 indicate different patterns of water column stratification and salinity. On-going analyses on planktonic and benthic foraminifers and oxygen isotopes will provide further insights into the climatic and oceanographic conditions characterizing these three sapropels

A coastal lagoon and barrier-laggon system in nw Adriatic Sea (Italy) dated back 10,000 years ago.

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Isatin Bis-Indole and Bis-Imidazothiazole Hybrids: Synthesis and Antimicrobial Activity

Isatin and its derivatives are important heterocycles found in nature and present in numerous bioactive compounds which possess various biological activities. Moreover, it is an essential building block in organic synthesis. The discovery of novel compounds active against human pathogenic bacteria and fungi is an urgent need, and the isatin may represent the suitable scaffold in the design of biologically relevant antimicrobials. A small library of 18 isatin hybrids was synthetized and evaluated for their antimicrobial potential on three reference strains: S. aureus, E. coli, both important human pathogens infamous for causing community- and hospital-acquired severe systemic infections; and C. albicans, responsible for devastating invasive infections, mainly in immunocompromised individuals. The study highlighted two lead compounds, 6k and 6m, endowed with inhibitory activity against S. aureus at very low concentrations (39.12 and 24.83 &micro;g/mL, respectively)

Parents’ Perception of Food Insecurity and of Its Effects on Their Children in Italy Six Months after the COVID-19 Pandemic Outbreak

The Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) pandemic and subsequent containment measures are causing an increase in food insecurity (FI) worldwide, with direct consequences on children&rsquo;s nutrition. We aimed to investigate the effects of the lockdown imposed in Italy on FI and changes in eating habits and body weight in the pediatric population 6 months after the beginning of the pandemic through a cross-sectional online survey proposed to parents of children &lt;18 and living in Italy. Among 5811 respondents, most of whom were Italian, living in Northern Italy, and with a wealthy household economy, 8.3% reported that their families were at risk of FI before the appearance of SARS-CoV-2 and, alarmingly, this percentage increased to 16.2% after the pandemic began, with households from Southern Italy being more at risk. Moreover, 27.3% of the parents reported that their children were eating more; an increase in &ldquo;junk food&rdquo; consumption was also found; 31.8% of the respondents declared an increase in children&rsquo;s weight; weight loss prevailed among adolescents. Since the SARS-CoV-2 pandemic is again requiring restrictions, our findings might serve as a warning to politicians to promote healthy lifestyles and provide assistance to the groups in need