Modelli evolutivi del magmatismo alcalino Cenozoico del Rift Antartico

All’interno della NVL sono stati studiati i prodotti della Daniell Peninsula, Mt. Rittmann, Cape Crossfire e Cape King assieme a Greene, Monteagle, McGee Igneous Complexes, al fine di capire quale possa essere stato il processo responsabile della loro evoluzione petrogenetica. In queste ultime due aree, gli affioramenti sono spesso composti da rocce intrusive mafiche, associate a rocce felsiche. Per ogni zona sono stati studiati a livello petrografico i prodotti più evoluti, seguiti poi da modellizzazioni petrologiche e interpretazioni dei dati geochimici ed isotopici. Sono stati effettuati modelli del bilancio di massa per i processi di cristallizzazione frazionata, e si sono ottenuti modelli di concentrazione degli elementi incompatibili, confrontabili con quelli reali. Si osservano un trend che va da composizioni basaltiche a trachitiche con ramificazione verso rioliti e fonoliti, e un altro trend da basaniti a trachiti fonolitiche. Il processo responsabile nell’evoluzione di entrambi i trend è stato per almeno il 90% la cristallizzaziona frazionata. Nell’ultimo stadio può essere ipotizzato smescolamento limitato a Cape Crossfire. Inoltre, grazie ai dati isotopici si nota che alcuni campioni possono aver subito contaminazione da crostale

Polyhydroxyalkanoate as a slow-release carbon source for in situ bioremediation of contaminated aquifers: from laboratory investigation to pilot-scale testing in the field

A pilot-scale study aiming to evaluate the potential use of poly-3-hydroxy-butyrate (PHB) as an electron donor source for in situ bioremediation of chlorinated hydrocarbons in groundwater was conducted. Compared with commercially available electron donors, PHB offers a restricted fermentation pathway (i.e., through acetic acid and molecular hydrogen) by avoiding the formation of any residual carbon that could potentially spoil groundwater quality. The pilot study was carried out at an industrial site in Italy, heavily contaminated by different chlorinated aliphatic hydrocarbons (CAHs). Prior to field testing, PHB was experimentally verified as a suitable electron donor for biological reductive dechlorination processes at the investigated site by microcosm studies carried out on site aquifer material and measuring the quantitative transformation of detected CAHs to ethene. Owing to the complex geological characteristics of the aquifer, the use of a groundwater circulation well (GCW) was identified as a potential strategy to enable effective delivery and distribution of electron donors in less permeable layers and to mobilise contaminants. A 3-screened, 30-m-deep GCW coupled with an external treatment unit was installed at the site. The effect of PHB fermentation products on the in situ reductive dechlorination processes were evaluated by quantitative real-time polymerase chain reaction (qPCR). The results from the first 4 months of operation clearly demonstrated that the PHB fermentation products were effectively delivered to the aquifer and positively influenced the biological dechlorination activity. Indeed, an increased abundance of Dehalococcoides mccartyi (up to 6.6 fold) and reduced CAH concentrations at the installed monitoring wells were observed

The "Oil-Spill Snorkel": an innovative bioelectrochemical approach to accelerate hydrocarbons biodegradation in marine sediments

This study presents the proof-of-concept of the "Oil-Spill Snorkel": a novel bioelectrochemical approach to stimulate the oxidative biodegradation of petroleum hydrocarbons in sediments. The "Oil-Spill Snorkel" consists of a single conductive material (the snorkel) positioned suitably to create an electrochemical connection between the anoxic zone (the contaminated sediment) and the oxic zone (the overlying O-2-containing water). The segment of the electrode buried within the sediment plays a role of anode, accepting electrons deriving from the oxidation of contaminants. Electrons flow through the snorkel up to the part exposed to the aerobic environment (the cathode), where they reduce oxygen to form water. Here we report the results of lab-scale microcosms setup with marine sediments and spiked with crude oil. Microcosms containing one or three graphite snorkels and controls (snorkel-free and autoclaved) were monitored for over 400 days. Collectively, the results of this study confirmed that the snorkels accelerate oxidative reactions taking place within the sediment, as documented by a significant 1.7-fold increase (p = 0.023, two-tailed t-test) in the cumulative oxygen uptake and 1.4-fold increase (p = 0.040) in the cumulative CO2 evolution in the microcosms containing three snorkels compared to snorkel-free controls. Accordingly, the initial rate of total petroleum hydrocarbons (TPH) degradation was also substantially enhanced. Indeed, while after 200 days of incubation a negligible degradation of TPH was noticed in snorkel-free controls, a significant reduction of 12 1% (p = 0.004) and 21 1% (p = 0.001) was observed in microcosms containing one and three snorkels, respectively. Although, the "Oil-Spill Snorkel" potentially represents a groundbreaking alternative to more expensive remediation options, further research efforts are needed to clarify factors and conditions affecting the snorkel-driven biodegradation processes and to identify suitable configurations for field applications

Modeling of gain and phase dynamics in quantum dot amplifiers

By means of an electron hole rate equation model we explain the phase dynamics of a quantum dot semiconductor optical amplifier and the appearance of different decay times observed in pump and probe experiments. The ultrafast hole relaxation leads to a first ultrafast recovery of the gain, followed by electron relaxation and, in the nanosecond timescale, radiative and non-radiative recombinations. The phase dynamics is slower and is affected by thermal redistribution of carriers within the dot. We explain the ultrafast response of quantum dot amplifiers as an effect of hole escape and recombination without the need to assume Auger processe

Metabolic and cardiovascular response to exercise in patients with type 1 diabetes

Physical activity is an effective therapeutic tool for cardiovascular risk prevention. However, exercise aerobic capacity of patients with type 1 diabetes (T1DM) has not been thoroughly investigated. Aim of the present study is to evaluate exercise aerobic capacity in patients with T1DM compared to a normal control population

Polarization dependence of electroluminescence from closely-stacked and columnar quantum dots

Quantum dots (QDs) have a potential for application in semiconductor optical amplifiers (SOAs), due to their high saturation power related to the low differential gain, fast gain recovery and wide gain spectrum compared to quantum wells. Besides all advantages, QDs realized by Stranski-Krastanov growth mode have a flat shape which leads to a gain anisotropy and a related transverse magnetic (TM) and -electric (TE) polarization dependence as compared to bulk material. This has so far prevented their applications in SOAs. It has been suggested that control of optical polarization anisotropy of the QD can be obtained through QD shape engineering, in closely stacked or columnar QDs (CQDs). To this aim, we have fabricated and tested SOA structures based on closely-stacked and columnar QDs. Closely-stacked InAs QDs with 4, 6 and 10nm GaAs spacer showed a minor improvement in the ratio of TM and TE integrated electroluminescence (EL) over standard QDs along with a strong reduction in efficiency. In contrast, a large improvement was obtained in CQDs, depending on the number of stacked submonolayers which can be attributed to the more symmetric shape of columnar QDs. A relatively small spectral separation (ΔE ~ 21meV) between TE- and TM-EL peaks has been observed showing that heavy- and light hole-like states, respectively are energetically close in these QDs. These results indicate that columnar QDs have a significant potential for polarization-independent QD SO

NaNet:a low-latency NIC enabling GPU-based, real-time low level trigger systems

We implemented the NaNet FPGA-based PCI2 Gen2 GbE/APElink NIC, featuring GPUDirect RDMA capabilities and UDP protocol management offloading. NaNet is able to receive a UDP input data stream from its GbE interface and redirect it, without any intermediate buffering or CPU intervention, to the memory of a Fermi/Kepler GPU hosted on the same PCIe bus, provided that the two devices share the same upstream root complex. Synthetic benchmarks for latency and bandwidth are presented. We describe how NaNet can be employed in the prototype of the GPU-based RICH low-level trigger processor of the NA62 CERN experiment, to implement the data link between the TEL62 readout boards and the low level trigger processor. Results for the throughput and latency of the integrated system are presented and discussed.Comment: Proceedings for the 20th International Conference on Computing in High Energy and Nuclear Physics (CHEP

Improved overall survival with Gemtuzumab Ozogamicin (GO) compared with best supportive care (BSC) in elderly patients with untreated acute myeloid leukemia (AML) not considered fit for intensive chemotherapy: final results from the randomized phase III study (AML-19) of the EORTC and gimema leukemia groups

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