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1.
In Italy solar thermal energy and energy from biogas are two possible means of reducing dependence on energy imports. Using a multiperiod LP model (MARKAL) the authors assessed the likely potential of both technologies under various circumstances. The study covered the period 1980–2005, in five segments of five years. It focused only on the subsystem of the energy end-uses which can be substituted for by solar thermal and biogas technologies. The overall non-renewable sources which can be saved in 20 years by these technologies total 450 PJ (1 PJ = 101 5 J) if the fuel prices rise at 0 per cent average annual, 1450 PJ if the fuel prices rise at 4.2 per cent average annual, 1860 PJ if the fuel prices rise at 7.2 per cent average annual and 3780 PJ if the fuel prices rise at 15 per cent average annual. However the most competitive technologies appear to be solar water heaters used mainly in the private and commercial sectors and biogas systems used mainly in the agricultural sector. The study was carried out by APRE under ENEA (formerly CNEN) contract and was intended to serve as an analytical basis for establishing an overall development and demonstration strategy for end-use renewable technologies in Italy.  相似文献   
2.
Using a multiperiodal LP model (MARKAL) the authors assessed the likely potential of solar thermal and biogas systems under various circumstances. The study covered the period 1980–2005, in five segments of five years. It focused only on the subsystem of the energy end-uses which can be substituted for by solar and biogas technologies. In this paper we show the main results of the study regarding the competitiveness of the single solar and biogas technologies in different scenarios and their sensitivity to incentives and prices, together with the essential technical data regarding demand and supply technologies which produced those results. The analysis performed of the potential penetration of renewable technologies into the Italian energy system shows that their contribution will remain very marginal if the price of conventional energy carriers remains constant in constant money. However, the objective of removing with renewable technologies 1.5 per cent of the total Italian energy consumption appears to be realistic in the short-medium term.  相似文献   
3.
Code-division multiple-access (CDMA) schemes based on block spreading implement the spreading of entire data blocks rather than single symbols, thus achieving a higher robustness against the frequency selectivity of the channel and allowing the use of efficient modulation/equalization schemes operating in the frequency domain (FD). In this paper, we present a new block CDMA (B-CDMA) system where a single cyclic prefix (CP) is used at the end of each spread block. This provides a higher spectral efficiency with respect to existing schemes. By observing that complete orthogonality among users is achievable only for half-loaded systems on dispersive channels, we introduce new criteria for the design of spreading and despreading sequences, which aim at minimizing the mean-square error at the output of the despreader. For the equalization of the received signal, we propose an iterative block decision feedback equalizer, which iterates between equalization and decoding. Equalization filters are designed to minimize the mean-square error and take into account the residual interference due to the nonorthogonality of the spreading sequences. The performance of B-CDMA is evaluated in an uplink wireless scenario and compared to existing CDMA schemes.  相似文献   
4.
The tumorigenic potential of B lymphocytes latently infected with EBV is effectively controlled by T cell immunity. The mechanisms of this T cell regulation, however, are incompletely understood. In this study, T lymphocytes were found to proliferate in response to serum-free supernatants of EBV-immortalized cells and to deplete them of growth factors required by the immortalized B cells for autocrine growth. Lactic acid was reported to account for approximately 90% of the autocrine growth factor activity in serum-free supernatants of EBV-immortalized cell lines. Synthetic lactic acid was now found to promote growth in activated T cells. In addition, B cell suppression resulting from coculture of EBV-infected B cells with autologous T cells was reversed by the addition of supernatants from EBV-immortalized cell lines. Thus, T cell competition for growth factors produced and utilized by EBV-immortalized B cells for continuous proliferation may represent an important and novel regulatory mechanism for the maintenance of EBV latency in B lymphocytes.  相似文献   
5.
Buried‐channel semiconductor heterostructures are an archetype material platform for the fabrication of gated semiconductor quantum devices. Sharp confinement potential is obtained by positioning the channel near the surface; however, nearby surface states degrade the electrical properties of the starting material. Here, a 2D hole gas of high mobility (5 × 105 cm2 V?1 s?1) is demonstrated in a very shallow strained germanium (Ge) channel, which is located only 22 nm below the surface. The top‐gate of a dopant‐less field effect transistor controls the channel carrier density confined in an undoped Ge/SiGe heterostructure with reduced background contamination, sharp interfaces, and high uniformity. The high mobility leads to mean free paths ≈ 6 µm, setting new benchmarks for holes in shallow field effect transistors. The high mobility, along with a percolation density of 1.2 × 1011cm?2, light effective mass (0.09me), and high effective g‐factor (up to 9.2) highlight the potential of undoped Ge/SiGe as a low‐disorder material platform for hybrid quantum technologies.  相似文献   
6.
DMP 728 showed a dose-dependent inhibition of platelet aggregation at doses of 0.05 to 0.9 mg per subject, with a maximal inhibition (> 90%) of platelet aggregation at doses of 0.9 mg per subject and higher. Minimal changes in bleeding time from baseline were observed at doses up to 0.6 mg per subject. At the 0.9 mg/subject dose level, bleeding time was prolonged by approximately twofold to threefold above the baseline. At higher doses (1.5 mg/subject to 3.9 mg/subject), bleeding time prolongation was > 30 minutes during the infusion. In all dose groups, bleeding times returned to the control value within 8 hours after cessation of the infusion. Maximum plasma concentration and area under the curve of DMP 728 increased linearly and proportionally to the dose. No clinical changes in vital signs, 12-lead electrocardiograms, physical examinations, coagulation tests, or stool hemoccult tests were observed at any of the doses. In conclusion, DMP 728 is a potent antiplatelet agent and well tolerated at doses ranging from 0.05 to 3.0 mg/subject.  相似文献   
7.
In human behaviour analysis, the visual focus of attention (VFOA) of a person is a very important cue. VFOA detection is difficult, though, especially in a unconstrained and crowded environment, typical of video surveillance scenarios. In this paper, we estimate the VFOA by defining the Subjective View Frustum, which approximates the visual field of a person in a three‐dimensional representation of the scene. This opens up to several intriguing behavioural investigations. In particular, we propose the Inter‐Relation Pattern Matrix, which suggests possible social interactions between the people present in a scene. Theoretical justifications and experimental results substantiate the validity and the goodness of the analysis performed.  相似文献   
8.
Burkitt's lymphoma (BL) cell lines carry a translocated c-myc gene and, in 60-80% of cases, exhibit mutations in the p53 tumor suppressor gene. We examined the potential role of the p53 gene in BL tumorigenicity using an in vitro assay that measures p53-dependent cell cycle arrest in the G1 phase of the cell cycle and an in vivo athymic murine model that detects differences in the tumorigenicity of BL cell lines. A highly significant inverse correlation was found between the ability of BL cells to arrest in G1 after irradiation and their tumorigenicity in athymic mice, consistent with the notion that loss of p53 function is associated with increased tumorigenicity. Inactivation of wild-type (wt) p53 function by expression of the human papillomavirus E6 protein in the AG876V BL cell line, which carries both wt and mutant p53 proteins, rendered the cell line significantly more tumorigenic in athymic mice. Transfection of the wt p53 gene into the p53 mutant and highly tumorigenic BL-41 cell line caused it to acquire wt p53 function and rendered it less tumorigenic in mice. In addition to confirming a role for the loss of p53 function in tumor progression, the data demonstrate that wt p53 protein can reduce BL tumorigenicity in vivo.  相似文献   
9.
Wang  Yanyan  Yin  Fulian  Liu  Jianbo  Tosato  Marco 《Multimedia Tools and Applications》2020,79(31-32):22355-22373
Multimedia Tools and Applications - Sentiment lexicon is used to judge the sentiments of words and plays a significant role in sentiment analysis. Existing sentiment lexicons ignore the sentimental...  相似文献   
10.
This study evaluates the overall effects of the present Italian Renewable Energy Supply of Electricity (RES-E) obligation and compares the contribution of each expected RES-E to the economic equilibrium mix resulting from computable economic equilibrium scenarios. The impact of the policies has been evaluated by means of a model of the Italian energy–environment system built with the MARKAL/TIMES methodology, which has been developed by the Energy Technology Systems Analysis Project of the International Energy Agency (IEA/ETSAP). Since the development of RES-E helps energy security, climate mitigation and the distribution of energy production revenues across the country, this study evaluates also an alternative scenario assuming a progressive increase of the RES-E obligation. Both scenarios are then compared with the targets fixed for each RES by the Italian White Paper on renewable energy source. Eventually the effectiveness of the RES-E policies implemented through the green-certificate mechanism are compared with the obligation to improve the efficiency of end-use devices fed by electricity and natural gas. Contrary to green-certificates policies, White certificates obligations increase energy security and GDP at the same time, because in principle they force end users to more rational choices.  相似文献   
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