208 research outputs found
Community core detection in transportation networks
This work analyses methods for the identification and the stability under
perturbation of a territorial community structure with specific reference to
transportation networks. We considered networks of commuters for a city and an
insular region. In both cases, we have studied the distribution of commuters'
trips (i.e., home-to-work trips and viceversa). The identification and
stability of the communities' cores are linked to the land-use distribution
within the zone system, and therefore their proper definition may be useful to
transport planners.Comment: 8 pages, 13 figure
Electrochemically Triggered Co-Conformational Switching in a [2]catenane Comprising a Non-Symmetric Calix[6]arene Wheel and a Two-Station Oriented Macrocycle
Catenanes with desymmetrized ring components can undergo co-conformational
rearrangements upon external stimulation and can form the basis for the development of molecular rotary motors. We describe the design, synthesis and properties of a [2]catenane consisting of a macrocycle—the ‘track’ ring—endowed with two distinct recognition sites (a bipyridinium and an ammonium) for a calix[6]arene—the ‘shuttle’ ring. By exploiting the ability of the calixarene to thread appropriate non-symmetric axles with directional selectivity, we assembled an oriented pseudorotaxane and converted it into the corresponding oriented catenane by intramolecular ring closing metathesis. Cyclic voltammetric experiments indicate that the calixarene wheel initially surrounds the bipyridinium site, moves away from it when it is reduced, and returns in the original position upon reoxidation. A comparison with appropriate model compounds shows that the presence of the ammonium station is necessary for the calixarene to leave the reduced bipyridinium site
Supporting information to the characterisation factors of recommended EF Life Cycle Impact Assessment methods: New methods and differences with ILCD
In 2013, the Environmental Footprint methodology has been established with a specific Recommendation (2013/179/EU), within the framework of the “Single Market for Green Products” communication (COM/2013/0196). The International Life Cycle Data system, developed since 2007, released in 2010 and continuously maintained by JRC, has been adopted in the EF framework. ILCD format and nomenclature were adopted as requirements for EF.
Given the different needs and goals of the EF, some methods for the Life Cycle Impact Assessment have been changed compared to ILCD (and therefore the elementary flows have been adapted accordingly, and to some extent, the format has been expanded).
The the LCIA methods are developed within the database as ILCD-formatted xml files to allow electronic import into LCA software; The LCIA methods are implemented as separate data sets which contain all the descriptive metadata documentation and the characterisation factors assigned to different elementary flows (that are also xml files within the DB).
This document provide a view on the changes occurred within the methods for the mid-point impact assessment (the EF is considering for now only impacts at the level of potential changes, not at the potential damage level, which was captured in ILCD scheme for the methods at the end-point level).
The changes and adaptations occurred within the ILCD scheme, that led to the creation of the current EF set of methods and a new package, based on ILCD format, containing new files for LCIA methods, can be summarized as follows:
• 6 methods are completely new, or updated according to the newest releases of the old methods adopted in ILCD.
• The elementary flow list has been fixed and expanded according to the needs of the new methods
• Within the new methods several flows have been spatially differentiated (in ILCD format the location attribute is resolved at the method level, not at the elementary flow level)
• For several flows that were not characterized (both in newly added methods and in the pre-existing ones that were not modified), a CF has been adopted, where a direct proxy for a specific substance/compartment was available.
• Specific exceptions, integrations or corrections have been implemented in different methods.
All these aspects are detailed within the document. Furthermore, additional files have been released, containing an exhaustive view of all the changes occurred in the transition phase between the ILCD and the EF scheme (see annex2). Additional updates will be released through the website of the European Platform on LCA (http://eplca.jrc.ec.europa.eu/).
Other methods (e.g. those related to toxicity aspects) are under development, during the editing of this document; therefore an updated version will be released as soon as the new recommended methods are defined.JRC.D.1-Bio-econom
Bioconversion of ovine scotta into lactic acid with pure and mixed cultures of lactic acid bacteria.
Abstract
Scotta is the main by-product in the making of ricotta cheese. It is widely produced in southern Europe and particularly in Italy where it represents a serious environmental pollutant due to its high lactose content. With the aim of evaluating whether scotta bioconversion into lactic acid can be considered as an alternative to its disposal, besides providing it with an added value, here the growth, fermentative performances, and lactic acid productions of pure and mixed cultures of Lactobacillus casei, Lactobacillus helveticus, and Streptococcus thermophilus were evaluated on ovine scotta-based media, without and with the addition of nutritional supplements. The outcomes indicate that ovine scotta can be utilized for the biotechnological production of lactic acid with yields up to 92%, comparable to those obtained on cheese-whey. Indeed, the addition of nutritional supplements generally improves the fermentative performances of lactic acid bacteria leading to about 2 g l−1 h−1 of lactic acid. Moreover, the use of mixed cultures for scotta bioconversion reduces the need for nutritional supplements, with no detrimental effects on the productive parameters compared to pure cultures. Finally, by using L. casei and S. thermophilus in pure and mixed cultures, up to 99% optically pure l-lactic acid can be obtained
Itinerari conoscitivi in città. Test di realtà virtuale nel miglioramento del design Italiano
Five years ago, the Department of Architectural History, Theory and Composition
of the University of Seville began a line of research and work on universal accessibility
and historical heritage. The current Curriculum for Architecture studies, from 2012 and
derived from the Bologna Plan, is based on competency-based learning. Along with the
specific ones for each subject, for each area of knowledge, others of a transversal nature
are established, such as universal accessibility and the reasonable use of IC
Mendelian breeding units <i>versus</i> standard sampling strategies: mitochondrial DNA variation in southwest Sardinia
We report a sampling strategy based on Mendelian Breeding Units (MBUs), representing an interbreeding group of individuals sharing a common gene pool. The identification of MBUs is crucial for case-control experimental design in association studies. The aim of this work was to evaluate the possible existence of bias in terms of genetic variability and haplogroup frequencies in the MBU sample, due to severe sample selection. In order to reach this goal, the MBU sampling strategy was compared to a standard selection of individuals according to their surname and place of birth. We analysed mitochondrial DNA variation (first hypervariable segment and coding region) in unrelated healthy subjects from two different areas of Sardinia: the area around the town of Cabras and the western Campidano area. No statistically significant differences were observed when the two sampling methods were compared, indicating that the stringent sample selection needed to establish a MBU does not alter original genetic variability and haplogroup distribution. Therefore, the MBU sampling strategy can be considered a useful tool in association studies of complex traits
Fast emitting nanocomposites for high-resolution ToF-PET imaging based on multicomponent scintillators
Time-of-Flight Positron Emission Tomography is a medical imaging technique,
based on the detection of two back-to-back {\gamma}-photons generated from
radiotracers injected in the body. Its limit is the ability of employed
scintillation detectors to discriminate in time the arrival of {\gamma}-pairs,
i.e. the coincidence time resolution (CTR). A CTR < 50 ps that would enable
fast imaging with ultralow radiotracer dose. Monolithic materials do not have
simultaneously the required high light output and fast emission
characteristics, thus the concept of scintillating heterostructure is proposed,
where the device is made of a dense scintillator coupled to a fast-emitting
light material. Here we present a composite polymeric scintillator, whose
density has been increased upon addition of hafnium oxide nanoparticles. This
enhanced by +300% its scintillation yield, surpassing commercial plastic
scintillators. The nanocomposite is coupled to bismuth germanate oxide (BGO)
realizing a multilayer scintillator. We observed the energy sharing between its
components, which activate the nanocomposite fast emission enabling a net CTR
improvement of 25% with respect to monolithic BGO. These results demonstrate
that a controlled loading with dense nanomaterials is an excellent strategy to
enhance the performance of polymeric scintillators for their use in advanced
radiation detection and imaging technologies
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Data-Driven Methodology for Knowledge Graph Generation Within the Tourism Domain
The tourism and hospitality sectors have become increasingly important in the last few years and the companies operating in this field are constantly challenged with providing new innovative services. At the same time, (big-) data has become the “new oil” of this century and Knowledge Graphs are emerging as the most natural way to collect, refine, and structure this heterogeneous information. In this paper, we present a methodology for semi-automatic generating a Tourism Knowledge Graph (TKG), which can be used for supporting a variety of intelligent services in this space, and a new ontology for modelling this domain, the Tourism Analytics Ontology (TAO). Our approach processes and integrates data from Booking.com, Airbnb, DBpedia, and GeoNames. Due to its modular structure, it can be easily extended to include new data sources or to apply new enrichment and refinement functions. We report a comprehensive evaluation of the functional, logical, and structural dimensions of TKG and TAO
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