1,721,084 research outputs found
Systems Biology Analysis of the Endocannabinoid System Reveals a Scale-free Network with Distinct Roles for Anandamide and 2-Arachidonoylglycerol
No full textAbstract We represented the endocannabinoid system (ECS) as a biological network, where ECS molecules are the nodes (123) and their interactions the links (189). ECS network follows a scale-free topology, which confers robustness against random damage, easy navigability, and controllability. Network topological parameters, such as clustering coefficient (i.e., how the nodes form clusters) of 0.0009, network diameter (the longest shortest path among all pairs of nodes) of 12, averaged number of neighbors (the mean number of connections per node) of 3.073, and characteristic path length (the expected distance between two connected nodes) of 4.715, suggested that molecular messages are transferred through the ECS network quickly and specifically. Interestingly, 75% of nodes are located on, or are active at the level of, the cell membrane. The hubs of ECS network are anandamide (AEA) and 2-arachidonoylglycerol (2-AG), which have also the highest value of betweeness centrality, and their removal causes network collapse into multiple disconnected components. Importantly, AEA is a ubiquitous player while 2-AG plays more restricted actions. Instead, the product of their degradation, arachidonic acid, and their hydrolyzing enzyme, fatty acid amide hydrolase, FAAH, have a marginal impact on ECS network, indeed their removal did not significantly affect its topology
Multi-temporal analysis of geographical-hierarchical structures in Italy
No full textIn this paper, we propose a model to analyse the dynamic of the urban system looking at the national and local level at the same time; this work is a sketch of a wider project running by few years. The width of the objective suggested to adopt an elementary (meaningful) model of the city system; this is a necessary condition to span the temporal (fifty years) and geographical (all the country) dimensions as defined in our work
Le trasformazioni del territorio italiano tra il 1951 e il 2001
No full textIn questo lavoro, è presentata una ricognizione diacronica delle modificazioni del territorio dal punto di vista insediativo su tutto il territorio nazionale tra il 1951 e il 2001.
Il territorio è modellato in una struttura relazionale gerarchica i cui nodi – i comuni - attraggono e sono attratti localmente materializzando, ordinatamente, l’intreccio del sistema urbano. L’estensione spaziale e temporale ha comportato un grande sforzo di elaborazione e sistematizzazione della base dati tanto sul versante geografico che su quello alfanumerico.
Nel corso della ricerca, sono state definite e sperimentate molteplici opzioni di modellazione L’implementazione del modello individua le strutture gerarchico-geografiche locali su tutto il territorio nazionale Per la loro analisi, sono stati messi a punto una serie di indicatori sia di tipo statistico (consistenza demografica e spaziale, numerosità degli elementi, etc.) che di “forma” ( indice di complessità, indice di diramazione, lunghezza delle catene di elementi, numerosità dei nodi sub-apicali, etc.). Per gli indicatori di tipo statistico, ciascuna struttura locale è comparata alla distribuzione complessiva dei comuni a livello nazionale. Gli indicatori di forma sono invece visti nella loro composizione a livello di singola struttura. Ogni struttura locale è quindi descritta analiticamente tanto nella sua forma (grafo gerarchico-geografico ad ogni data di riferimento) tanto nelle singole variazioni della struttura stessa
La forma della città: luoghi di Roma da cambiare /conservare
Get PDFIl problema é la progressiva perdita di forma leggibile della città nata sulla base dei processi di accrescimento fisico del secondo dopoguerra e degli strumenti di pianificazione urbanistica da quel periodo utilizzati.
Una nuova consapevolezza del valore della forma urbana, intesa come contesto ed insieme esito di qualsiasi altra politica urbana, può esplicarsi in una strategia di (ri)progettazione morfologica metropolitana, un “progetto”, anche fisicamente inteso, di (ri)costruzione della leggibilità.
L’ipotesi é che la leggibilità della città metropolitana possa essere fondata sulla forma - fisica, percepita, e interpretabile – dello spazio delle reti e dei nodi più frequentati dal cittadino metropolitano.
Il riferimento ad un paradigma formale di tipo reticolare/nodale, i cui elementi sono assunti come luoghi e oggetti urbani da progettare sostiene le ipotesi di applicabilità ed efficienza della strategia, per l’aderenza alle politiche di intervento correnti (nodi e reti sono oggetto di trasformazione a motivo delle loro funzioni di servizio ai flussi di spostamento), e per la fattibilità economica (l’intorno di reti e nodi è il luogo di massimizzazione dell’investimento)
Hierarchical analysis and aggregation of territorial units for more detailed levels in the “NUTS” classification
No full textAt the beginning of the 1970s, the Commission set up the “Nomenclature of Statistical Territorial Units” (NUTS) as a single, coherent system for dividing up the European Union's territory in order to produce regional statistics for the Community. Since in Italy the LAU level 1 has not yet been defined, a committee established by National Statistical Institute (ISTAT) is studying a possible delimitation. This work is set in this background, reporting only one of several diverse hypothesis developed within the committee. A set of common principles for LAU1 have been defined, deriving them from the NUTS Regulation. Consequently, likewise to NUTS, territorial units specific to certain fields of activity have been excluded, while this branch of still running experiments aims to define units of a full general nature. The expected result is the identification of a number of “settlements systems”, where the underlying law is some kind of general relationship existing between communes. So, it has been adopted a very general model of aggregation, applied to municipalities. The model considers two kinds of constraints for the aggregation: i) a hierarchical ranking of settlements, and ii) the relations between settlements, in the geographical space domain. With these constraints, an aggregative algorithm is defined, whose meaning will result by the specific variables that are used: i) to establish the settlements hierarchy, and ii) to evaluate the spatial distribution of settlements
In Vitro Development of Sheep Preantral Follicles
No full textPreantral ovarian follicles isolated from prepubertal sheep
ovaries were individually cultured for 6 days in the presence of
increasing doses of FSH (ranging from 0.01 to 1 mg/ml) and
under two different oxygen concentrations, 20% and 5% O2.
Follicle development was evaluated on the basis of antral cavity
formation as well as the presence of healthy cumulus oocyte
complexes. Follicle growth was enhanced by FSH addition to
culture medium, while the use of a low oxygen concentration
slightly stimulated this process. However, when follicles were
cultured in the presence of high doses of FSH (1 mg/ml) and
under low oxygen concentration, a high proportion of them
showed the presence of an antral cavity and of a healthy cumulus-
oocyte complex. In addition, under this specific culture
condition sheep preantral follicles released higher levels of estradiol
as compared to those secreted at lower FSH concentrations
or under 20% O2. When the meiotic competence of oocytes
derived from follicles cultured at 1 mg/ml FSH was assessed,
no significant difference was recorded between the two
oxygen groups. These results show that the culture conditions
here identified are beneficial to in vitro growth and differentiation
of sheep preantral follicles
Urban planning as project management: a limited rationality model
No full textWe consider program proposals as separate projects and use an incremental decision process (incremental functional formulation) backed by methods of optimisation through incremental and interactive decision processes which have been developed in operations research. These methods fit the ill-structured problems in planning better than the conventional optimisation methods. We'll conclude showing one of the possible concrete applications of our model to a real-life case, where one of the main results was a suggested expense of € 4 millions leading to the 90% of the result possible with the cost of € 10 millions (but with just a 40% expenditure)
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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