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排序方式: 共有2097条查询结果,搜索用时 15 毫秒
11.
Leonardo Badia Andrea Baiocchi Alfredo Todini Simone Merlin Silvano Pupolin Andrea Zanella Michele Zorzi 《Wireless Communications, IEEE》2007,14(1):36-43
Multicellular networks based on the IEEE 802.16 standard appear to be very promising candidates to provide end users with broadband wireless access. However, they also pose interesting challenges in terms of radio resource management, where several design choices are not specified in the standard, intentionally left open to implementors. For this reason, we focus in this article on scheduling and resource allocation, and investigate how they could operate in a cross-layer fashion. In particular, we describe the principles of joint scheduling and resource allocation for IEEE 802.16 operating in AMC mode, and discuss the critical role played by physical layer considerations, especially intercell interference estimation and channel state awareness, in the obtained performance. This leads to identifying key open issues and possible general solutions 相似文献
12.
Anna Grazia Mignani Peter R. Smith Leonardo Ciaccheri Antonio Cimato Graziano Sani 《Sensors and actuators. B, Chemical》2003,90(1-3):157-162
In spectral nephelometry, absorption spectroscopy and nephelometry are innovatively combined to provide simultaneous online monitoring of color and turbidity of edible oils. Spectral nephelometry instrumentation consists of an optoelectronic device that measures the absorption spectrum of the oil sample at different angles. Data processing, carried out by principal component analysis (PCA), allows identification of the oil sample and creates a two-dimensional map as a fingerprint of oil types. 相似文献
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Leonardo Setti Pier Giorgio Pifferi Gaetano Lanzarini 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1995,64(1):41-48
A new mathematical model for n-alkane biodegradation in crude oil, heavy oil and paraffinic mixtures is described. The pattern of n-alkane degradation as a function of the inverse of hydrocarbon chain length reported in this paper can be considered as general behaviour for many aerobic n-alkane biodegradation processes. A new interpretation of n-alkane biodegradation as a function of surface tension, is given. A mathematical expression was obtained starting from the degradation values of n-alkane and relative surface tension, which is a parameter independent of fermentation conditions. An interesting parameter, b, was identified which represented the accelerating conversion factor for n-alkane biodegradation. The findings suggested that the n-alkane biodegradation. The findings suggested that he n-alkane biodegradation rate may be affected by the fermentation condition (agitation, aeration, etc.) and by the strain of microorganism, while the behaviour pattern of n-alkane degradation was essentially linked to the substrate characteristics (molecular structure, molecular weight and density). 相似文献
16.
López-Robles J. R. Cobo M. J. Gutiérrez-Salcedo M. Martínez-Sánchez M. A. Gamboa-Rosales N. K. Herrera-Viedma E. 《Applied Intelligence》2021,51(9):6547-6568
Applied Intelligence - Applied Intelligence is one of the most important international scientific journals in the field of artificial intelligence. From 1991, Applied Intelligence has been oriented... 相似文献
17.
Silvia Saturio Alicja M. Nogacka Marta Surez Nuria Fernndez Laura Mantecn Leonardo Mancabelli Christian Milani Marco Ventura Clara G. de los Reyes-Gaviln Gonzalo Solís Silvia Arboleya Miguel Gueimonde 《International journal of molecular sciences》2021,22(7)
The establishment of the gut microbiota poses implications for short and long-term health. Bifidobacterium is an important taxon in early life, being one of the most abundant genera in the infant intestinal microbiota and carrying out key functions for maintaining host-homeostasis. Recent metagenomic studies have shown that different factors, such as gestational age, delivery mode, or feeding habits, affect the gut microbiota establishment at high phylogenetic levels. However, their impact on the specific bifidobacterial populations is not yet well understood. Here we studied the impact of these factors on the different Bifidobacterium species and subspecies at both the quantitative and qualitative levels. Fecal samples were taken from 85 neonates at 2, 10, 30, 90 days of life, and the relative proportions of the different bifidobacterial populations were assessed by 16S rRNA–23S rRNA internal transcribed spacer (ITS) region sequencing. Absolute levels of the main species were determined by q-PCR. Our results showed that the bifidobacterial population establishment is affected by gestational age, delivery mode, and infant feeding, as it is evidenced by qualitative and quantitative changes. These data underline the need for understanding the impact of perinatal factors on the gut microbiota also at low taxonomic levels, especially in the case of relevant microbial populations such as Bifidobacterium. The data obtained provide indications for the selection of the species best suited for the development of bifidobacteria-based products for different groups of neonates and will help to develop rational strategies for favoring a healthy early microbiota development when this process is challenged. 相似文献
18.
Alessia Vignoli Emanuela Risi Amelia McCartney Ilenia Migliaccio Erica Moretti Luca Malorni Claudio Luchinat Laura Biganzoli Leonardo Tenori 《International journal of molecular sciences》2021,22(9)
Precision oncology is an emerging approach in cancer care. It aims at selecting the optimal therapy for the right patient by considering each patient’s unique disease and individual health status. In the last years, it has become evident that breast cancer is an extremely heterogeneous disease, and therefore, patients need to be appropriately stratified to maximize survival and quality of life. Gene-expression tools have already positively assisted clinical decision making by estimating the risk of recurrence and the potential benefit from adjuvant chemotherapy. However, these approaches need refinement to further reduce the proportion of patients potentially exposed to unnecessary chemotherapy. Nuclear magnetic resonance (NMR) metabolomics has demonstrated to be an optimal approach for cancer research and has provided significant results in BC, in particular for prognostic and stratification purposes. In this review, we give an update on the status of NMR-based metabolomic studies for the biochemical characterization and stratification of breast cancer patients using different biospecimens (breast tissue, blood serum/plasma, and urine). 相似文献
19.
Occurrence patterns of alien freshwater turtles in a large urban pond ‘Archipelago’ (Rome,Italy): Suggesting hypotheses on root causes
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Maria Paola Di Santo Leonardo Vignoli Giuseppe M. Carpaneto Corrado Battisti 《Lakes & Reservoirs: Research and Management》2017,22(1):56-64
The patterns of the occurrence and distribution of alien freshwater turtle species in an urban pond archipelago (Rome, Italy) were analysed, with the aim of exploring the role of a set of factors (type of ponds, landscape context, size area, distance from the nearest road) with a generalized linear model approach. A total of 311 ponds subdivided in three types (fountains, small basins, lakes) embedded in different landscape contexts (public parks, private parks, urban areas) at differing distances from the nearest road were sampled. Six non‐native freshwater turtle species in 31 sites were recorded (9.97%). Lakes exhibited the highest occurrence rates of alien freshwater turtles, compared to small basins and fountains. Freshwater turtle species in urbanized areas were only observed in parks (both public and private). In both the public and private parks, the lakes exhibited the highest percentage of occupied sites, with fountains being the lowest. A direct and significant relationship was observed between pond size and species richness. The distance from the nearest road did not appear to affect species richness. A first interpretation of the data from this study facilitated the postulation of two a posteriori hypotheses that should be tested, as follows: (i) the causal process of turtle release is random, and the rate of extinction (and recapture) is higher in smaller ponds, thus producing the observed pattern; and (ii) the turtle release is not random, and people actively select the ponds they consider more suitable for their pet animals. In this study, it appears the lakes were perceived by those who abandon their pets as the most ecologically suitable habitats among other pond types to accommodate the different species of turtles. Knowledge of people's attitudes in regard to releasing pet animals also might assist managers of public green spaces to develop strategies aimed to preserve local biodiversity, and to educate the public about the conservation issue represented by the alien species. 相似文献
20.
J. Javier Gutiérrez J. Carlos Palencia Michael González Harbour 《Real-Time Systems》2014,50(2):230-269
The ARINC-664, Part 7 (AFDX) standard defines a communication network based on Ethernet and the UDP/IP protocols. Contrary to general-purpose Ethernet, the timing behavior in AFDX is deterministic due to the use of special network switches and end systems with static routing tables and traffic policing at the sending end through mechanisms called virtual links. Even though the latencies in this network are bounded, there are scheduling and contention effects that need to be analyzed. In this paper we develop a response-time analysis for multipacket messages transmitted through an AFDX network including the scheduling of the virtual links and sub-virtual links, and also the contention in the end systems and in the switches. This analysis allows us to obtain worst-case latencies and output jitter for the network messages with a precise modeling of the sending and receiving ends. These results can be integrated in a holistic approach with the response time analysis of the threads in the processing nodes to obtain end-to-end response times in heterogeneous distributed systems. 相似文献