1,531 research outputs found
Particle detection in rare gas solid crystals: a feasibility experimental study—exploring new ways for dark matter searches: Exploring new ways for dark matter searches
No full textThis article reviews the experimental activity that has been carried out within the INFN DEMIURGOS research and development (R&D) project. This R&D concerns the study of possible innovative experimental approaches for the detection of low-energy-releases of feeble interacting particles within the matter. Possible applications could be the direct investigation of Dark Matter candidates. The idea behind the proposed scheme is to exploit rare gas solid crystals both pure and doped, combined with the in-vacuum single electron detection technology. In pure materials, the signal can be the charge produced directly during the ionization. Laser-assisted processes can instead be used to probe low-energy-releases in doped materials. Both these mechanisms should lead to a detectable electronic signal triggered by the incoming particle. In such a way, energy threshold ranging from meV to tens of eV could in principle be reached, opening-up the possibility to probe theoretically, well-motivated regions of unexplored electroweak parameter-space and thus test the existence of light Dark Matter candidates. The activity presented here has been performed to understand the mechanisms at the basis of the proposed detection scheme and possible showstopper. The experimental investigations refer to the research and development phases about: the crystal growing techniques and the corresponding set-up, the electrons’ extraction from rare gas crystals to the vacuum environment, and finally the spectroscopic studies on atomic species embedded into rare gas matrices
Effects of water and nitrogen management on fibrous root distribution and turnover in sugar beet
No full textTwo field trials were carried Out in two years in heavy soils of NE Italy, with the aim of studying the effects of water and nitrogen management on fibrous root distribution and dynamics in sugar beet (cv. Dorotea). In conditions of moderate water deficit (year 2002, Conselice, Ravenna, clay soil), two water regimes (irrigation to 100% of potential evapotranspiration, and rainfed) were factorially combined with three rates of nitrogen application (180, 90, 0 kg ha(-1)). Irrigation increased volumetric root length density (RLD(v)) without N application and at the medium N rate - a common amount in beet cultivation - but reduced it at the maximum N dose. The medium N rate increased RLDv and shifted root distribution towards shallow layers, regardless of water regime.
In the conditions of marked drought of 2003 (Legnaro, Padova, silty-loam soil), at a single rate of N supply (90 kg ha-1) irrigation increased total production (length) of fibrous roots throughout the soil profile (1.8 m), except in the 0.5-1 m interval, and improved the length of standing living roots during the season. Although the maximum root depth at the end of the season was similar in the two water regimes (about 1.9 m), irrigated roots reached the saturated soil layers 10 days earlier than in rainfed plants. The main result was reduced root turnover in deep soil layers (>1 m) and an increase at the surface in the rainfed treatments in conditions of drought, a probable mechanism of adaptation to a more marked gradient of soil Moisture compared with irrigation
La conservazione della coltura della barbabietola da zucchero nell'ambiente mediterraneo: il ruolo del turnover radicale in rapporto al rifornimento idrico
No full textINFLUENCE OF THE DEMAGNETIZATION ON THE POLARIZATION OF THE THERMAL RDIATION EMITTED BY HOT COBALT WIRES
No full textThe polarization P of thermal radiation emitted by a hot cobalt wire in the temperature range from T � 400. K up to melting is studied for the first time. The radiation is linearly polarized perpendicularly to the wire. P decreases from 30 %. just above room temperature down to 6:5 % near melting and is continuous across the martensitic hcp fcc transition at Tm � 700 K and across the Curie point at Tc � 1400K. However, P shows a rapid decrease for T≳1000K and, contrary to previous measurements with tungsten wires, it hysteretically behaves if the temperature change is reversed. This behavior is rationalized by accounting for the thermal demagnetization of the wire with magnetic domain size change
Wild wall rocket (Diplotaxis erucoides L.) leaves functionality and postharvest quality as affected by cut and cold storage
No full textIn the last few years, fresh-cut industry has largely spread due to the growing demand for ready-to-eat vegetables. Consumers are now searching for meals easy to prepare but, at the same time, they pay great attention to sensory quality and health-related properties. Among ready-to-eat food, rocket is highly appreciated as a salad vegetable. Moreover, it is a source of glucosinolates, carotenoids, and phenolic compounds, which are well-known as healthy phytochemicals and determinants of the nutraceutical quality of these species. The aim of this work was to evaluate the effects of cut on the quality and storability of white wall rocket (Diplotaxis erucoides L. 'Wasabi') leaves. White wall rocket was grown in hydroponics, and leaves were harvested at the commercial stage for the minimally processing industry. About 10 g of entire and cut leaves were placed in airtight jars and stored in dark conditions at 8±1°C for up to 7 days. The analysis of the headspace gas composition (CO2, O2, and RH%) was performed in each jar after 7 days of storage for estimating the respiration rate possibly induced by the cut. Chlorophyll a fluorescence-related parameters were measured in the entire and cut leaves, at harvest and after storage, in order to evaluate the possible changes in the efficiency of the photosystem II (PSII). Phenolic compounds were determined at harvest and after 7 days of storage as well. No significant difference was found in respiration-related parameters. The significant differences in all chlorophyll a fluorescence related-parameters, showed a progressive increase of stress conditions during storage, especially for cut leaves, at the end of the storage period. Moreover, a significant increment was found in the phenolic compounds (phenolic index) between samples at harvest and after the storage period. In conclusion, the results of the present work show the sensibility of chlorophyll a fluorescence related-parameters in detecting stress conditions of leaf tissues, and a strong correlation between stress condition and the increase of secondary metabolites
Sound and music computing using AI: designing a standard
No full textWhile there are currently various approaches that define and adapt the conditions in which the user experiences content or service for several music and audio-related applications including entertainment, communication, audio documents preservation/restoration, we are missing worldwide accepted standards that enable data exchange and interoperability based on common interfaces for such applications. The Moving Picture, Audio and Data Coding by Artificial Intelligence (MPAI) is an international non-profit organization whose mission is to develop such standards. Relying on Artificial Intelligence (AI), MPAI creates a workflow of AI Modules (AIM) that are interchangeable and upgradable without necessarily changing the logic of the application. A specific area of work, MPAI Context-based Audio Enhancement (MPAI-CAE), is showing tremendous possibilities for the Sound and Music Computing (SMC) community. MPAI-CAE applies context information to the input content to deliver the audio output via the most appropriate protocol. Three MPAI-CAE case studies particularly relevant for the SMC community will be presented in this paper: Audio recording preservation (ARP), a use case that covers the whole “philologically informed” archival process of an audio document, from the active sound documents preservation to the access to digitized files; Audio-on-the-go (AOG), which aims to improve safety and listening quality for situations in which the users are in motion in different environments; and Emotion-enhanced speech (EES), a use case that implements a user-friendly system control interface that generates speech with various levels of emotions
Progress in methods for investigating the fibrous root system in sugar beet
No full text13-14 February 2002 Brussels, Belgiu
Studying root distribution with geostatistics
No full textGeostatistics was applied to a set of RLD (Root Length Density) data of maize obtained from auger sampling. A reciprocal linear-logarithmic function was found to fit the spatial trend of RLD, and was subtracted from the original data for correct application of geostatistics. Subsequent use of variography enabled description of the relations of root density with space and provided information on the size of root clusters. Spatial relations also served as a basis for subsequent estimation by kriging of RLD in unsampled locations, thus yielding bi-dimensional RLD maps with higher accuracy than those obtained by traditional methods of interpolation. Comparing two maize hybrids of different yields, the maps showed substantial differences in the proportion of root length in peripheral positions of the cross-row vertical profile and in the incidence of zones with critical density of colonisation. The trend of variograms also indicated larger root clusters in the higher-yielding hybrid, together with more uniform colonisation of soil - a profitable feature in conditions of limited soil resources. The trial highlighted some drawbacks in the application of geostatistics to feasible schemes of soil-coring in wide-spaced crops
The Effect of Drought on Sisymbrium officinale (L.) Wild Species for Potential Cultivation as a Leafy Vegetable
No full textLeafy vegetables are common components of the human diet and are a source of antioxidant, vitamins, minerals, and bioactive compounds. Fresh-cut or minimally processed industries are always looking for product innovations. Many wild species, based on their composition, can be evaluated as potential vegetables. In this work, hedge mustard has been studied as a potential leafy vegetable, and two wild populations were grown under 100% crop water requirement (WR) and 50% WR. The effect of water reduction was monitored using non-destructive measurements of chlorophyll a fluorescence and by the analytical determination of primary or secondary metabolism associated parameters such as sugars, anthocyanins, carotenoids, phenolic compounds, and nitrate concentrations. The results demonstrated that hedge mustard [Sisymbrium officinale (L.) Scop.] can be grown with 50% WR without yield reduction. The yield was not statistically different between the two water regimes and ranged from 22.3 to 40 g plant−1 FW. Leaf nitrate concentrations showed high variability in the MI population grown with 100% WR, while in the BG population, they did not change when the WR was shifted from 100% to 50%. The total phenols were 25% higher in the leaves of plants grown under 50% WR in both wild populations. The total sugars and anthocyanins did not show significant variations. Chlorophyll a fluorescence parameters did not show significant changes. The results suggest that hedge mustard can be grown in environments with limited water availability or in the winter season using less water to avoid disease development. The highest yield was obtained from the BG population
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