Modelling tracer dispersion from landfills

Several wind tunnel experiments of tracer dispersion from reduced-scale landfill models are presented in this paper. Different experimental set-ups, hot-wire anemometry, particle image velocimetry and tracer concentration measurements were used for the characterisation of flow and dispersion phenomena nearby the models. The main aim of these experiments is to build an extensive experimental data set useful for model validation purposes. To demonstrate the potentiality of the experimental data set, a validation exercise on several mathematical models was performed by means of a statistical technique. The experiments highlighted an increase in pollutant ground level concentrations immediately downwind from the landfill because of induced turbulence and mean flow deflection. This phenomenon turns out to be predominant for the dispersion process. Tests with a different set-up showed an important dependence of the dispersion phenomena from the landfill height and highlighted how complex orographic conditions downwind of the landfill do not affect significantly the dispersion behaviour. Validation exercises were useful for model calibration, improving code reliability, as well as evaluating performances. The Van Ulden model proved to give the most encouraging results

Near-infrared spectroscopy study of tourniquet-induced forearm ischaemia in patients with coronary artery disease

Near-Infrared Spectroscopy (NIR) can be employed to monitor local changes in haemodynamics and oxygenation of human tissues. A preliminary study has been performed in order to evaluate the NIRS transmittance response to induced forearm ischaemia in patients with coronary artery disease (CAD). The population consists in 40 patients with cardiovascular risk factors and angiographically documented CAD, compared to a group of 13 normal subjects. By inflating and subsequently deflating a cuff placed around the patient arm, an ischaemia has been induced and released, and the patients have been observed until recovery of the basal conditions. A custom LAIRS spectrometer (IRIS) has been used to collect the backscattered light intensities from the patient forearm throughout the ischaemic and the recovery phase. The time dependence of the near-infrared transmittance on the control group is consistent with the available literature. On the contrary, the magnitude and dynamics of the NIRS signal on the CAD patients show deviations from the documented normal behavior, which can be tentatively attributed to abnormal vessel stiffness. These preliminary results, while validating the performance of the IRIS spectrometer, are strongly conducive towards the applicability of the NIRS technique to ischaemia analysis and to endothelial dysfunction characterization in CAD patients with cardiovascular risk factors.Publisher PD

Experimental determination of the frequency and field dependence of Specific Loss Power in Magnetic Fluid Hyperthermia

Magnetic nanoparticles are promising systems for biomedical applications and in particular for Magnetic Fluid Hyperthermia, a promising therapy that utilizes the heat released by such systems to damage tumor cells. We present an experimental study of the physical properties that influences the capability of heat release, i.e. the Specific Loss Power, SLP, of three biocompatible ferrofluid samples having a magnetic core of maghemite with different core diameter d= 10.2, 14.6 and 19.7 nm. The SLP was measured as a function of frequency f and intensity of the applied alternating magnetic field H, and it turned out to depend on the core diameter, as expected. The results allowed us to highlight experimentally that the physical mechanism responsible for the heating is size-dependent and to establish, at applied constant frequency, the phenomenological functional relationship SLP=cH^x, with 2<x<3 for all samples. The x-value depends on sample size and field frequency/ intensity, here chosen in the typical range of operating magnetic hyperthermia devices. For the smallest sample, the effective relaxation time Teff=19.5 ns obtained from SLP data is in agreement with the value estimated from magnetization data, thus confirming the validity of the Linear Response Theory model for this system at properly chosen field intensity and frequency

Two new pulsating low-mass pre-white dwarfs or SX Phenix stars?*

Context. The discovery of pulsations in low-mass stars opens an opportunity for probing their interiors and to determine their evolution, by employing the tools of asteroseismology. Aims. We aim to analyze high-speed photometry of SDSSJ145847.02$+$070754.46 and SDSSJ173001.94$+$070600.25 and discover brightness variabilities. In order to locate these stars in the $T_{\rm eff} - \log g$ diagram we fit optical spectra (SDSS) with synthetic non-magnetic spectra derived from model atmospheres. Methods. To carry out this study, we used the photometric data obtained by us for these stars with the 2.15m telescope at CASLEO, Argentina. We analyzed their light curves and we apply the Discrete Fourier Transform to determine the pulsation frequencies. Finally, we compare both stars in the $T_{\rm eff} - \log g$ diagram, with known two pre-white dwarfs, seven pulsating pre-ELM white dwarf stars, $\delta$ Scuti and SX Phe stars. Results. We report the discovery of pulsations in SDSSJ145847.02$+$070754.46 and SDSSJ173001.94$+$070600.25. We determine their effective temperature and surface gravity to be $T_{\rm eff}$ = 7 972 $\pm$ 200 K, $\log g$ = 4.25 $\pm$ 0.5 and $T_{\rm eff}$ = 7 925 $\pm$ 200 K, $\log g$ = 4.25 $\pm$ 0.5, respectively. With these parameters these new pulsating low-mass stars can be identified with either ELM white dwarfs (with ~ 0.17 Mo) or more massive SX Phe stars. We identified pulsation periods of 3 278.7 and 1 633.9 s for SDSSJ145847.02$+$070754.46 and a pulsation period of 3 367.1 s for SDSSJ173001.94$+$070600.25. These two new objects together with those of Maxted et al. (2013, 2014) indicate the possible existence of a new instability domain towards the late stages of evolution of low-mass white dwarf stars, although their identification with SX Phe stars cannot be discarded.Comment: 5 pages, 5 figures, 1 table, accepted for publication in A&A

Effectiveness of the GAEC cross compliance standards Rational management of set aside, Grass strips to control soil erosion and Vegetation buffers along watercourses on surface animal diversity and biological quality of soil

Landscape simplification and loss of natural and semi-natural habitats are the major causes of biodiversity decrease in agricultural landscapes. In order to mitigate the effects of intensive agricultural management the Ministry of Agricultural, Food and Forestry Policies in Italy has included the agronomic measures Rational management of set aside, Grass strips to control soil erosion and Vegetation buffers along watercourses in the decree on cross compliance. In this paper we review the results of a field research performed in Central Italy. The aim of the study was to evaluate the efficacy of the above mentioned GAEC standards for animal diversity enhancement. Using different animal groups as indicators, superficial Arthropod fauna and Herpetofauna, we found striking differences in the biodiversity levels of areas characterized by the application or by the lack of GAEC standards, with the latter being characterized by a significatively impoverished fauna. In particular, the set aside area and the buffer of riparian vegetation resulted of primary importance to allow higher biodiversity levels. Also the analysis of the biological quality of the soil, as assessed through the QBS-ar index based on edaphic micro-Arthropod fauna, indicated a higher quality of semi-natural habitats with respect to arable lands

Afasia Progressiva Primaria: identificazione di n profilo neuropsicologico predittivo e correlazione con biomarcatori liquorali e neuroimaging

Un gruppo internazionale di clinici, esperti in disturbi progressivi del linguaggio, si riun\uec per tre volte tra il 2006 ed il 2009, con lo scopo di creare un classificazione definitiva delle PPA e delle sue tre varianti, utilizzando come punto di partenza i criteri esistenti in letteratura (Tabella 1 - Mesulam, 2003) ma integrandoli alla luce delle informazioni fornite dalle strumentazioni pi\uf9 recenti (neuroimaging, dosaggio liquorale). Le linee guida cosi delineate prevedono che, affinch\ue9 la diagnosi di PPA sia verosimile, l'insorgenza del disturbo linguistico deve apparire insidiosa e dall'andamento ingravescente; l'afasia deve essere evidente sia nel linguaggio spontaneo che in seguito ad una valutazione neuropsicologica e deve rappresentare, almeno nella fase iniziale, il sintomo d\u2019esordio, nonch\ue9 il segno clinico pi\uf9 evidente. L'autonomia nelle attivit\ue0 di base ed in quelle strumentali della vita quotidiana deve essere preservata, ad eccezione di quelle attivit\ue0 strettamente correlate all'utilizzo del linguaggio. Tutte le altre funzioni cognitive dovrebbero risultare coinvolte solo successivamente, ma l'afasia rappresenter\ue0 comunque il deficit cognitivo pi\uf9 evidente per tutta la durata della malattia. I principali criteri di esclusione includono un disturbo mnesico o visuo-spaziale nelle fasi iniziali della malattia, marcati disturbi comportamentali e la presenza di lesioni focali (ictus, tumori). La recente classificazione della PPA proposta da Gorno-Tempini in tre differenti varianti: non-fluente (NFPA), semantica (SVPA) e logopenica (LPA) (Gorno-Tempini et al., 2011), richiede un processo diagnostico complesso, che si articola su tre livelli differenti: l\u2019assessment neuropsicologico, il neuroimaging e l\u2019analisi liquorale. In questo studio abbiamo correlato i risultati ottenuti in test specifici, scelti per indagare le caratteristiche linguistiche tipiche di ogni variante di PPA, con i livelli liquorali delle proteine A\u3b2, Tau e Ptau, ed il pattern atrofico riscontrato alla risonanza magnetica. Lo scopo della ricerca \ue8 quello di creare una batteria neuropsicologica in grado di effettuare ipotesi diagnostiche e realizzare diagnosi differenziale tra le singole varianti di PPA gi\ue0 nelle fasi iniziali della malattia. Lo scopo della nostra ricerca \ue8 proprio questo: individuare test cognitivi che pi\uf9 di altri siano predittivi nell\u2019individuare la possibile presenza di PPA gi\ue0 nelle fasi inziali della patologia. Si \ue8 partiti dalla consapevolezza che i domini cognitivi maggiormente compromessi siano la capacit\ue0 di denominazione, la comprensione, la scrittura, la lettura, la ripetizione e la capacit\ue0 di fruibilit\ue0 lessicale. Si sono, infatti, selezionate cinque prove: la batteria di Milano II, per l\u2019indagine delle competenza linguistiche, il Token Test, per valutare la comprensione di ordini verbali, le fluenze verbali, per indagare la fruibilit\ue0 lessicale, il Boston Naming Test per la capacit\ue0 di denominazione e il Mini Mental State Examination per l\u2019efficienza cognitiva globale. Analizzando la correlazione tra i tre diversi marcatori considerati (test neuropsicologici, localizzazione delle aree atrofiche e dosaggio liquorale) \ue8 emerso che la presenza di agrammatismo, e di aprassia verbale rappresentano i deficit neuropsicologici pi\uf9 sensibili per la diagnosi di NFPA gi\ue0 nelle fasi iniziali della patologia. Punteggi al di sotto del range normativi, ottenuti nelle prove di ripetizione (sia di parole, non parole che di frasi complesse), rappresenta un buon predittore per la diagnosi di LPA. Infine, punteggi patologici nelle prove di lettura (soprattutto di frasi) e di denominazione di stimoli visivi (Boston Naming Test) potrebbe essere un indicatore precoce per la diagnosi di SPA. Obiettivo futuro sar\ue0 quello di ampliare il campione e proseguire con follow-up longitudinali a 6-8 mesi per delineare il progredire della patologia. Inoltre, per ciascuno dei test somministrati si cercher\ue0 di determinare dei valori soglia specifici per la diagnosi di PPA in modo da consentirne pieno utilizzo diagnostico, gi\ue0 nelle fasi iniziali della malattia, soprattutto in contesti clinici in cui non sia possibile determinare i biomarcatori liquorali

The impact of cirrus clouds on tropical troposphere-to-stratosphere transport

International audienceAlthough it is well known that air enters the stratosphere preferentially through upwelling in the tropics, the exact mechanisms of troposphere-to-stratosphere transport (TST) are still unknown. Previously proposed mechanisms have been found either to be too slow (e.g., clear sky upwelling) to provide agreement with in situ tracer measurements, or to be insufficient in mass flux to act as a major supply for the Brewer-Dobson circulation (e.g., convective overshooting). In this study we evaluate whether the lofting of air via cirrus cloud-radiation interaction might offer an alternative path for TST, which is responsible for a significant fraction of the observed air mass transport. We find that a combination of deep convection and subsequent upwelling associated with cirrus clouds and clear sky can explain the supply of air for the Brewer-Dobson circulation. Thus, upwelling associated with cirrus clouds offers a mechanism for the missing second stage, which links the first stage of TST, deep convection, to the third stage, the Brewer-Dobson circulation