Structure of Turbulence in Katabatic Flows below and above the Wind-Speed Maximum

Measurements of small-scale turbulence made over the complex-terrain atmospheric boundary layer during the MATERHORN Program are used to describe the structure of turbulence in katabatic flows. Turbulent and mean meteorological data were continuously measured at multiple levels at four towers deployed along the East lower slope (2-4 deg) of Granite Mountain. The multi-level observations made during a 30-day long MATERHORN-Fall field campaign in September-October 2012 allowed studying of temporal and spatial structure of katabatic flows in detail, and herein we report turbulence and their variations in katabatic winds. Observed vertical profiles show steep gradients near the surface, but in the layer above the slope jet the vertical variability is smaller. It is found that the vertical (normal to the slope) momentum flux and horizontal (along the slope) heat flux in a slope-following coordinate system change their sign below and above the wind maximum of a katabatic flow. The vertical momentum flux is directed downward (upward) whereas the horizontal heat flux is downslope (upslope) below (above) the wind maximum. Our study therefore suggests that the position of the jet-speed maximum can be obtained by linear interpolation between positive and negative values of the momentum flux (or the horizontal heat flux) to derive the height where flux becomes zero. It is shown that the standard deviations of all wind speed components (therefore the turbulent kinetic energy) and the dissipation rate of turbulent kinetic energy have a local minimum, whereas the standard deviation of air temperature has an absolute maximum at the height of wind-speed maximum. We report several cases where the vertical and horizontal heat fluxes are compensated. Turbulence above the wind-speed maximum is decoupled from the surface, and follows the classical local z-less predictions for stably stratified boundary layer.Comment: Manuscript submitted to Boundary-Layer Meteorology (05 December 2014

Phase separations, liquid crystal ordering and molecular partitioning in mixtures of PEG and DNA oligomers

Liquid crystals (LCs) ordering of DNA and RNA oligomers relies on the presence of inter-duplex end-to-end attraction, driving the formation of linear aggregates. Such interactions are gauged, at a macroscopic level, by the osmotic pressure at the isotropic-nematic and nematic-columnar phase transitions. We studied aqueous solutions of PEG and DNA duplex-forming oligomers, finding that there is a wide range of concentrations in which these mixtures phase separate into coexisting PEG-rich and DNA-rich phases, the latter being either in the isotropic state or ordered as a nematic or columnar LC. We determined the phase diagram in mixtures of PEG and DNA duplexes with different terminal motifs\u2013blunt ends, sticky overhangs, aggregation-preventing overhangs\u2013and measured the partitioning of the species in the coexisting phases. On this basis, we determined the osmotic pressure as a function of the DNA concentration across the phase diagram. We compared the equation of state obtained in this way with both the Carnahan\u2013Starling equation of state for hard spheres and with the pressure predicted by computer simulations of a system of aggregating cylinders. We obtain a good agreement between experiments and simulations, and end-to-end attraction energies of the order of 6 kcal/mol, a bit larger than expected, but still in agreement with the current models for DNA-DNA interactions

Studenti svantaggiati e fattori di promozione della resilienza

Molti studi evidenziano l’impatto che il contesto socio-economico e diverse caratteristiche degli studenti, quali il genere e il background migratorio, hanno sul raggiungimento di adeguate competenze in matematica. Questa situazione pone un problema di equità del sistema educativo e formativo: alcuni gruppi di giovani sono infatti svantaggiati in partenza per motivi indipendenti dal loro impegno nello studio. L’obiettivo del presente lavoro è valutare la presenza di fattori, su cui è possibile un intervento da parte degli insegnanti, che consentano a studenti svantaggiati di raggiungere risultati di eccellenza. Il contributo mira a identificare fattori associati non solo a una compensazione dello svantaggio legato alle condizioni di sfondo degli studenti, ma a una vera e propria inversione delle previsioni in termini di competenze raggiunte. I risultati mostrano l’impatto che l’appartenenza geografica, il background socio-economico-culturale delle scuole e delle famiglie e il genere, nella loro interazione, esercitano nel definire situazioni di forte svantaggio di partenza per gli studenti. Allo stesso tempo, gli esiti mettono in luce il ruolo protettivo giocato da alcune strategie d’insegnamento, dalle convinzioni di autoefficacia degli studenti e da altri fattori legati a specifiche situazioni di contesto.Many studies showed the impact that the socio-economic context and students’ characteristics, such as gender and migratory background, have on mathematical performance. This situation poses a problem of equity of the educational system: some groups of young people are in fact disadvantaged for reasons independent of their commitment to the study. The aim of this paper is to evaluate the presence of factors on which teachers can intervene, allowing disadvantaged students to achieve excellence. The contribution aims to identify associated factors not only to compensate for the disadvantage associated with student background conditions, but to a real reversal of predictions in terms of skills acquired. The results show the impact that geographic membership, the socio-economic-cultural background of schools and families and gender, in their interaction, exert in defining situations of major disadvantage for students. At the same time, there is evidence for the protective role played by some teaching strategies, student self-beliefs, and other factors related to specific background situations

Trace metal distributions in Posidonia oceanica and sediments from Taranto Gulf (Ionian Sea, Southern Italy)

Distribution of metals (Hg, Pb, Sn, Cu, Cd and Zn) was determined in sediments and in different tissues of Posidonia oceanica collected from San Pietro Island, Taranto Gulf (Ionian Sea, Southern Italy). In seagrass, results, compared with metal concentrations in sediments, showed that the highest concentrations of Hg, Pb, Sn and Cu were found in the roots, while in the green leaves were found the highest levels of Cd and Zn. Instead the lowest metal concentrations were found in the basal part of the leaf. Levels of  metals in the leaves were similar to those found by other authors in uncontaminated areas of the Mediterranean Sea. Mercury levels in roots were correlated to levels in sediments. This could demonstrate the plant memorizes sediments contamination . This study reinforces the usefulness and the relevance of Posidonia oceanica as an indicator of spatial metal contamination and an interesting tool for environmental quality evaluation

Heavy metals monitoring in mussels Mytilus galloprovincialis from the Apulian coasts (Southern Italy)

Concentrations of six heavy metals (Cd, Cr, Cu, Hg, Pb and Zn) and one semi-metal (As) were determined in tissues of mussels Mytilus galloprovincialis collected along the Apulian coasts (Mediterranean sea). This project, performed in 2009, was targeted toward the assessment of levels and spatial distribution of metals in the environment in order to evaluate the coastal water quality using mussels as bioindicators and health risk for mussel consumers.The concentrations (mg/kg d.w.) of these metals ranged from 6.35 to 76.17 for arsenic (As), 0.38 to 2.54 for cadmium (Cd), 0.96 to 9.46 for chromium (Cr), 5.26 to 19.22 for copper (Cu), 0.10 to 0.81 for mercury (Hg), 25.00 to 110.51 for zinc (Zn) and from 0.37 to 3.25 for lead (Pb). These levels were lower than the permissible limits set by European Commission and FAO with the exception for Cr in three sampling stations. Evaluation of the risk associated to molluscs consumption for human health suggested that there is no evident risk for a moderate Mytilus g. consumer, however heavy metals concentrations must be monitored periodically and carefully with respect to the consumers health

Possibile origine e consistenza di un popolamento di Quercus trojana Webb subsp. trojana (Fagaceae) nel Bosco della Ficuzza (Palermo, Sicilia

Possible origin and demographic asset of a population of Quercus trojana Webb subsp. trojana (Fagaceae) in the wood of Ficuzza (Palermo, Sicily). The first record of Macedonian oak in Sicily is reported. The finding consists of 73 adult and 4 young individuals. A morphometric analysis of all of them, along with an assessment of their phytosanitary status was carried out. They all grow between 700 and 850 m a.s.l. on a 2,30 ha area, characterized by a land mosaic of shrubland and forest patches. Notwithstanding two years of researches, no ultimate proof has been found on their alien status. On this purpose, several alternative hypothesis are formulated and their strengths and weaknesses are discussed. Considering that the environmental conditions of Ficuzza fit very well the ecological requirements of Quercus trojana, even the native status of local population cannot be totally rejected. On the other hand, many data support its recent introduction. In fact, according to interviews to old forest workers, archive documents and aerial photos, most part of the trees of this area have been planted just few years after the end of the Second World War, and dendrochronological analyses have pointed out that the biggest Macedonian oaks of Sicily are no more than 50-60 years old. Whatever the origin of local Macedonian oak population is, the presence of natural renovation testifies, at least, its full naturalisation within the Sicilian territory

Therapeutic sequences in patients with grade 1−2 neuroendocrine tumors (NET): an observational multicenter study from the ELIOS group

Purpose: Many different treatments are suggested by guidelines to treat grade 1−2 (G1−G2) neuroendocrine tumors (NET). However, a precise therapeutic algorithm has not yet been established. This study aims at identifying and comparing the main therapeutic sequences in G1−G2 NET. Methods: A retrospective observational Italian multicenter study was designed to collect data on therapeutic sequences in NET. Median progression-free survival (PFS) was compared between therapeutic sequences, as well as the number and grade of side effects and the rate of dose reduction/treatment discontinuation. Results: Among 1182 patients with neuroendocrine neoplasia included in the ELIOS database, 131 G1–G2 gastroenteropancreatic, lung and unknown primary NET, unresectable or persistent/relapsing after surgery, treated with ≥2 systemic treatments, were included. Four main therapeutic sequences were identified in 99 patients: (A) somatostatin analogs (SSA) standard dose to SSA high dose (n = 36), (B) SSA to everolimus (n = 31), (C) SSA to chemotherapy (n = 17), (D) SSA to peptide receptor radionuclide therapy (PRRT) (n = 15). Median PFS of the second-line treatment was not reached in sequence A, 33 months in sequence B, 20 months in sequence C, 30 months in sequence D (p = 0.16). Both total number and severity of side effects were significantly higher in sequences B and C than A and D (p = 0.04), as well as the rate of dose reduction/discontinuation (p = 0.03). Conclusions: SSA followed by SSA high dose, everolimus, chemotherapy or PRRT represent the main therapeutic sequences in G1−G2 NET. Median PFS was not significantly different between sequences. However, the sequences with SSA high dose or PRRT seem to be better tolerated than sequences with everolimus or chemotherapy

Composition of arthropod species assemblages in Bt-expressing and near isogenic eggplants in experimental fields

The environmental impact of genetically modified (GM) plants in experimental fields has been examined in several ways, in particular with respect to the dynamics of specific nontarget organisms. The approach of sampling for biodiversity in agroecosystems to compare complex patterns could also be useful in studying potential disruptions caused by GM crops. In this study, we set up replicated field plots of Bt-expressing eggplants and near isogenic untransformed eggplants as a control. We monitored the presence and abundance of herbivore and predator arthropods in weekly visual samplings of the plant canopy for three growing seasons (2001-2003). Insect species were pooled in organismal taxonomic units (OTUs); three multivariate methods were used to compare species assemblage as an estimate of insect biodiversity. This multistep statistical approach proved to be efficient in recognizing association patterns, as evidenced by the data for the target species Leptinotarsa decemlineata Say (Coleoptera: Chrysomelidae) clearly showing a significant association with the control plots. All the analyses indicate a comparable species assemblage between transgenic and near isogenic eggplant areas. Our results suggest that some taxa may warrant more specific study. For example, Alticinae beetles (Coleoptera: Chrysomelidae) were alternatively more abundant in either of the two treatments, and their overall abundance was significantly higher on transgenic eggplants. In light of these results and because of their taxonomic proximity to the target species, these herbivores may represent an important nontarget group to be further studied. Moreover, some sap feeders (e.g., Homoptera: Cicadellidae) were more abundant on Bt-expressing plants in some samples in all 3 yr

Innovative teaching on photovoltaic generation

One of the most important technologies for the renewable energy production is the Photovoltaic (PV) one. In the last decades, the enormous growth in the world of Photovoltaic installation capacity, and future trends, makes the knowledge of this topic fundamental for engineers working in the energy field with this competence, and not only. Thus, for students enrolled in industrial engineering courses, appropriate and innovative teaching methods are necessary. This paper aims to describe the structure of the course 'Photovoltaic Power Generation' in which solar resource and the photovoltaic generators, including power electronics, are explained. The topics of traditional theoretical lectures are presented, with the links to practical exercises and laboratories

Advances in Materials and Technologies for Gas Sensing from Environmental and Food Monitoring to Breath Analysis

Gas sensing research experiences a worldwide revival in the last years. From one side, the emergence of novel sensing materials enables unprecedented capacities for improving the device performances. From the other, the increasing opportunities for applications impacting current societal priorities highly motivate further studies. Here, this field is reviewed with special attention to the emerging approaches and the most recent breakthroughs, challenges, and perspectives. In particular, this study focuses on: 1) the sensing layers analyzing recent trends toward nanostructured, low-dimensional and composite materials; and 2) the latest achievements and targets in terms of applications, from environmental monitoring to food aroma identification and quality control up to the healthcare sector with breath analysis and diseases diagnosis