578 research outputs found
L'area delle risorgive nel sistema insediativo mesolitico: alcuni esempi dal pordenonese
The authors present the work undertaken on the lithic material collected in the spring area between Orcenico Superiore and Savorgnano (Pordenone-Italy). The sites are located on an NE-SW elongated Lateglacial gravel ridge, which to the present day is to be considered a stable area (i.e. preserved from alluvial and erosive action of Tagliamento and Meduna rivers). Different periods are represented in the lithic industries, spanning from the Mesolithic to the Bronze Age. This paper presents the results of the study carried out on the Mesolithic industries, mainly to be ascribed to the Castelnovian tradition. The typological composition of the assemblages shows different activities which could be associated with residential camps, without any particular specialization although this kind of interpretation could be biased by the non systematic nature of the findings. Different operational chains were in place, aiming to produce either bladelets or flakes. Raw materials are mostly of local origin, although few pieces were brought in from the Prealps, showing a North-South mobility along river routes. At the same time, there are scarce lithic materials imported from the upper part of the Udine plain, which is rich in good quality flint pebbles. Further technological and typological differences show a rather neat separation between sites on either sides of Tagliamento river. When we consider the distribution of Mesolithic sites in Friuli, a logistical settlement system seems to emerge: bigger sites are located at the edge of ecologically differentiated areas in connection with stable water sources such as the spring area between Orcenico and S. Vito al Tagliamento and the piedmont; complementary to those, task-related short-term sites characterised by less materials and fewer lithic types are found in the Prealps at middle altitude
APLICAÇÃO DE PERFIS DE VARREDURA NA ANÁLISE GEOMORFOLÓGICA DO RELEVO DE BORDA PLANÁLTICA E MAPEAMENTO DE SUPERFÍCIES ESTRUTURAIS
O presente trabalho teve como principal objetivo a aplicação de perfis de varredura para análise geomorfológica na borda planáltica entre o Segundo e Terceiro Planaltos Paranaenses. Os perfis de varredura permitem reconstituir a inclinação dos planos tangenciais às linhas de cumeada e a identificação de faixas de transição de patamares. Foram identificadas oito superfícies estruturais (SE), que são controladas e delimitadas por falhas normais e definem o Alto Estrutural de Mauá da Serra
Flame pyrolysis synthesis of mixed oxides for glycerol steam reforming
Flame spray pyrolysis was used to produce nanosized Ni-based catalysts starting from different mixed oxides. LaNiO3 and CeNiO3 were used as base materials and the formulation was varied by mixing them or incorporating variable amounts of ZrO2 or SrO during the synthesis. The catalysts were tested for the steam reforming of glycerol. One of the key problems for this application is the resistance to deactivation by sintering and coking, which may be increased by (1) improving Ni dispersion through the production of a Ni-La or Ni-Ce mixed oxide precursor, and then reduced; (2) using an oxide as ZrO2, which established a strong interaction with Ni and possesses high thermal resistance; (3) decreasing the surface acidity of ZrO2 through a basic promoter/support, such as La2O3; and (4) adding a promoter/support with very high oxygen mobility such as CeO2. A further key feature is the use of a high temperature synthesis, such as flame spray pyrolysis, to improve the overall thermal resistance of the oxides. These strategies proved effective to obtain active and stable catalysts at least for 20 h on stream with very limited coke formation
Search for vector-boson resonances decaying into a top quark and a bottom quark using pp collisions at √s = 13 TeV with the ATLAS detector
A search for a new massive charged gauge boson, W′, is performed with the ATLAS detector at the LHC. The dataset used in this analysis was collected from proton-proton collisions at a centre-of-mass energy of √s = 13 TeV, and corresponds to an integrated luminosity of 139 fb−1. The reconstructed tb invariant mass is used to search for a W′ boson decaying into a top quark and a bottom quark. The result is interpreted in terms of a W′ boson with purely right-handed or left-handed chirality in a mass range of 0.5–6 TeV. Different values for the coupling of the W′ boson to the top and bottom quarks are considered, taking into account interference with single-top-quark production in the s-channel. No significant deviation from the background prediction is observed. The results are expressed as upper limits on the W′ → tb production cross-section times branching ratio as a function of the W′-boson mass and in the plane of the coupling vs the W′-boson mass
Search for direct production of electroweakinos in final states with one lepton, jets and missing transverse momentum in pp collisions at √s = 13 TeV with the ATLAS detector
Search for magnetic monopoles and stable particles with high electric charges in √s = 13 TeV pp collisions with the ATLAS detector
We present a search for magnetic monopoles and high-electric-charge objects using LHC Run 2 √s = 13 TeV proton-proton collisions recorded by the ATLAS detector. A total integrated luminosity of 138 fb−1 was collected by a specialized trigger. No highly ionizing particle candidate was observed. Considering the Drell-Yan and photon-fusion pair production mechanisms as benchmark models, cross-section upper limits are presented for spin-0 and spin-1/2 magnetic monopoles of magnetic charge 1gD and 2gD and for high-electric-charge objects of electric charge 20 ≤ |z| ≤ 100, for masses between 200 GeV and 4000 GeV. The search improves by approximately a factor of three the previous cross-section limits on the Drell-Yan production of magnetic monopoles and high-electric charge objects. Also, the first ATLAS limits on the photon-fusion pair production mechanism of magnetic monopoles and high-electric-charge objects are obtained
Photocatalytic degradation of acetone in gas-phase: comparison between nano and micro-sized TiO2
Volatile Organic Compounds (VOCs) are widely used in industrial processes and for domestic activities, so generating water and air pollution. Well-known in-door sources of VOCs include cigarette smoke, building materials, paints, lacquers, glues and cleaning products [1]. In particular, the use of paints in industrial processes is responsible for the widespread utilization of organics solvents, such as acetone. Acetone (CH3COCH3) is a common chemical used extensively in a variety of in-dustrial and domestic applications. Therefore, we chose it as a model contaminant. Photocatalytic oxidation of acetone is based on the following overall reaction:
CH3COCH3 + 4O2 \u2192 3CO2 + 3H2O
The reaction occurs through radical mechanism car-ried out by hydroxyl radicals, with the formation of sev-eral intermediate products such as formaldehyde, formic acid, methanol and acetaldhehyde [2].
The TiO2 photodegradation of organic compounds has been proposed as an alternative Advanced Oxidation Processes (AOP) for the decontamination of air, since the photocatalytic oxidation of organic compounds in gas phase appears to be a promising process for the re-mediation of polluted air.
In this paper the photocatalytic efficiency towards acetone degradation of four commercial samples, two micro-sized and two nano-sized TiO2 powders is com-pared. The purpose of this study is to evaluate the feasi-bility of using micro-sized TiO2 instead of nanometric particles, which results in a greater environmental im-pact and higher production costs if compared to the for-mer on
Lo sviluppo delle conoscenze genomiche in vite e il loro potenziale utilizzo nella viticoltura attuale e futura
Nel 2007 sono stati pubblicati i risultati del
sequenziamento e dell\u2019analisi dettagliata del genoma
di Vitis vinifera frutto di due iniziative indipendenti,
una italo-francese e l\u2019altra italo-americana. Questi
risultati costituiscono la base per studi futuri e gettano
le fondamenta per l\u2019adozione di metodologie innovative
per sviluppare e rafforzare la viticoltura italiana e
mondiale del XXI secolo. In questa review verranno
illustrate le potenzialit\ue0 delle tecnologie derivate dalla
conoscenza del genoma come ad esempio lo sviluppo
di strumenti per l\u2019analisi di espressione genica su
larga scala, e riportati alcuni esempi inerenti al loro
impiego attuale e futuro in viticoltura
Stress-Induced GSK3 Regulates the Redox Stress Response by Phosphorylating Glucose-6-Phosphate Dehydrogenase in Arabidopsis.
Diverse stresses such as high salt conditions cause an increase in reactive oxygen species (ROS), necessitating a redox stress response. However, little is known about the signaling pathways that regulate the antioxidant system to counteract oxidative stress. Here, we show that a Glycogen Synthase Kinase3 from Arabidopsis thaliana (ASKα) regulates stress tolerance by activating Glc-6-phosphate dehydrogenase (G6PD), which is essential for maintaining the cellular redox balance. Loss of stress-activated ASKα leads to reduced G6PD activity, elevated levels of ROS, and enhanced sensitivity to salt stress. Conversely, plants overexpressing ASKα have increased G6PD activity and low levels of ROS in response to stress and are more tolerant to salt stress. ASKα stimulates the activity of a specific cytosolic G6PD isoform by phosphorylating the evolutionarily conserved Thr-467, which is implicated in cosubstrate binding. Our results reveal a novel mechanism of G6PD adaptive regulation that is critical for the cellular stress response
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