4,010 research outputs found
Covering your face on Facebook.Managing identity through untagging and deletion
This paper describes the ways in which Facebook users manage their\ud
online identities through untagging and deleting photos to make sure images are\ud
interpreted in a desirable way. Using data collected from an online survey and\ud
thirty in-depth interviews with American adult Facebook users, the authors argue\ud
that identity management can best be understood as the combination of\ud
constructive and destructive practices through which users control not only their\ud
self-presentation (projection), but also the statements others make about them\ud
(suppression)
Modeling urbanization patterns with generative adversarial networks
In this study we propose a new method to simulate hyper-realistic urban
patterns using Generative Adversarial Networks trained with a global urban
land-use inventory. We generated a synthetic urban "universe" that
qualitatively reproduces the complex spatial organization observed in global
urban patterns, while being able to quantitatively recover certain key
high-level urban spatial metrics.Comment: 4 pages, 4 figure
Multiplex networks in metropolitan areas: generic features and local effects
Most large cities are spanned by more than one transportation system. These
different modes of transport have usually been studied separately: it is
however important to understand the impact on urban systems of the coupling
between them and we report in this paper an empirical analysis of the coupling
between the street network and the subway for the two large metropolitan areas
of London and New York. We observe a similar behaviour for network quantities
related to quickest paths suggesting the existence of generic mechanisms
operating beyond the local peculiarities of the specific cities studied. An
analysis of the betweenness centrality distribution shows that the introduction
of underground networks operate as a decentralising force creating congestions
in places located at the end of underground lines. Also, we find that
increasing the speed of subways is not always beneficial and may lead to
unwanted uneven spatial distributions of accessibility. In fact, for London --
but not for New York -- there is an optimal subway speed in terms of global
congestion. These results show that it is crucial to consider the full,
multimodal, multi-layer network aspects of transportation systems in order to
understand the behaviour of cities and to avoid possible negative side-effects
of urban planning decisions.Comment: 12 pages, 8 figures. Final version with an additional discussion on
the total congestio
"Pia come la canto io", rassegna in prospettiva sul concept album del 2007. Transposiciones y relaciones intertextuales entre música- literatura y literatura-música
Questo lavoro prende in esame i testi, le figure retoriche, e le risorse narrative poste in atto in quest'opera che unisce in un chiasmo passato e presente, letteratura e musica.
La figura di Pia de' Tolomei è stata ripresa diverse volte nella letteratura, dal Duecento ai giorni nostri. Tra le creazioni più note troviamo l'opera di Gaetano Donizetti e Salvadore Cammarano (1836) a sua volta liberamente ispirato al poema di Bartolomeo Sestini (1822), alcuni romanzi come quello di Carolina Invernizio (1879) e due film degli anni '40 del Novecento.
Nell'anno 2007, la artista rock Gianna Nannini, nota per la sua traiettoria, ha pubblicato un concept album1 dal nome Pia come la canto io, incentrato appunto su questa figura.Fil: Strano, Mariano. Universidad Nacional de Rosario. Facultad de Humanidades y Artes. Escuela de Lenguas; Argentina
Il Mare Nei Tormentoni Estivi : Il Caso Di Giuni Russo
In questo lavoro esporrò alcuni dei topoi letterari presenti nei testi delle canzoni di Giuni Russo (1951-2004), col fine individuare le ragioni che hanno portato alcune di esse al successo, relegandone altre ad un pubblico di nicchia.
Nei suoi oltre vent’anni di carriera, Giuni Russo ha spaziato dalla musica sacra, (musicando testi di Giovanni della Croce e Santa Teresa d’Avila), alle hit dell'estate, passando da interessantissime fusioni tra jazz e musica lirica con una versatilità che ha destato lo stupore di diversi critici.
Malgrado la ricercatezza di alcuni suoi album, e la profondità di alcuni dei suoi testi, al grande pubblico sono pervenute solo alcune canzonette estive dai ritmi incalzanti, melodie di facile ascolto e testi attaccaticci.
Canzoni da spiaggia come "Alghero", "Un estate al mare", "Limonata cha-cha-cha" o "Mediterranea" superano di dieci volte la popolarità media degli altri suoi pezzi. Quale ruolo riveste il mare in queste creazioni, tanto da inclinare la bilancia dalla sua parte al momento di farle diventare canzoni? Perché ha un impatto così forte nei tormentoni dell'estate?
Dal momento che l'industria discografica persegue il profitto, i suoi sforzi saranno naturalmente orientati alle vendite. Il prodotto-canzone dovrà dunque essere oggetto di desiderio. È in questo gioco compositivo che viene a inserirsi il meccanismo dell'identificazione soggettiva. Il mare appare e scompare, è un posto che c'è, ma lo si sogna quando non c'è, e diventa appunto oggetto di desiderio per il suo valore nell'immaginario degli ascoltatori. Lontano da "Il mare d'inverno" di Loredana Berté, la presenza baluginante di questo mare crea un tessuto narrativo nel quale passa da protagonista a sottofondo delle canzoni più ascoltate della Russo. Nelle pagine successive cercherò di esporre le sue caratteristiche, le sue funzioni e le sue connotazioni nei testi dei brani presi in esame.Fil: Strano, Mariano. Universidad Nacional de Rosario. Facultad de Humanidades y Artes. Escuela de Lenguas; Argentina
The simplicity of planar networks
Shortest paths are not always simple. In planar networks, they can be very
different from those with the smallest number of turns - the simplest paths.
The statistical comparison of the lengths of the shortest and simplest paths
provides a non trivial and non local information about the spatial organization
of these graphs. We define the simplicity index as the average ratio of these
lengths and the simplicity profile characterizes the simplicity at different
scales. We measure these metrics on artificial (roads, highways, railways) and
natural networks (leaves, slime mould, insect wings) and show that there are
fundamental differences in the organization of urban and biological systems,
related to their function, navigation or distribution: straight lines are
organized hierarchically in biological cases, and have random lengths and
locations in urban systems. In the case of time evolving networks, the
simplicity is able to reveal important structural changes during their
evolution.Comment: 8 pages, 4 figure
Loss-of-function of leptin receptor impairs metabolism in human cardiomyocytes
Background and aims: Leptin resistance or leptin signalling deficiency are associated with increased risk of diabetic cardiomyopathy and heart failure, which is a leading cause of obesity- and diabetes type 2 (T2DM)-related morbidity and mortality. Various metabolic disturbances are involved in this pathogenesis, such as elevated glucose and fatty acid levels, insulin resistance and altered myocardial substrate utilization. Rodent models provided useful insights into the underlying molecular mechanisms of obese- and T2DM-associated cardiometabolic diseases, however, they cannot fully recapitulate the disease phenotype of obese or T2DM patients. The aims of this study were to study the effect of leptin receptor (LEPR) mutations on the leptin-mediated signalling pathways in human cardiomyocytes, and to investigate glucose and fatty acid metabolism in the heart under (patho)physiological conditions. Methods and results: To study the role of LEPR in human cardiomyocytes (CMs), human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) were used as a model. In the first part of this study, LEPR expression and function was investigated in wild type (WT)-iPSC-CMs by PCR and Western Blot. LEPR protein expression was almost not detectable in iPSCs and during early cardiac differentiation stages, however mRNA LEPR expression was comparable in the different steps of cardiac development. Importantly, LEPR protein expression was observed in WT-iPSC-CMs at the maturation stages, indicating that LEPR plays an important role in matured CMs. Thanks to CRISPR/Cas9 technology, LEPR mutations were introduced into iPSCs. Among the several clones obtained, 1B2 LEPRΔ/Δ-iPSC line was fully characterized and showed normal capacity to differentiate into spontaneously beating CMs. Although the B27 medium represents a well-established medium to cultivate iPSC-CMs, it has limitations for studying CM metabolism due to its high concentration of insulin and glucose, but low concentration of fatty acids. Physiological medium condition (F2) including physiological range of glucose, insulin and fatty acids was found to be fundamental to study LEPR signalling pathway in iPSC-CMs. Western blot analysis showed functional LEPR downstream pathway activation in WT-iPSC-CMs, while the absence of LEPR function was demonstrated in LEPRΔ/Δ-iPSC-CMs cultured in F2 medium. Moreover, improved medium condition, offered by the F2 medium, ameliorates insulin sensitivity as result of increased insulin-dependent AKT phosphorylation in WT-iPSC-CMs, while loss of LEPR function was associated with downregulation of insulin pathway activation. Additionally, leptin direct effect was observed on the regulation of glucose metabolism in WT-iPSC-CMs by reducing glycolytic fluxes, which was not observed in LEPRΔ/Δ-iPSC-CMs, as measured by 13C-isotope-assisted glucose metabolic flux. These data indicate that the signalling interaction between insulin and leptin is important in regulation of glucose metabolism and is abolished in LEPRΔ/Δ-iPSC-CMs. The matured WT-iPSC-CMs in F2 medium display adult CM-like metabolic phenotype such as enhanced mitochondrial respiration and glycolytic function, as measured by Seahorse analyser, compared to the same group cultured in the B27 medium. The mutation generated in LEPRΔ/Δ-iPSC-CMs caused an “energy starvation” status which led to increased AMPK phosphorylation compared to the WT group in B27 medium, which was associated with lower mitochondrial oxygen consumption rate (OCR) linked basal respiration and ATP production. In the next part of this study, the long-term leptin treatment of iPSC-CMs under physiological medium conditions in the presence of physiological range of insulin, glucose, and fatty acids (F2+) influenced LEPR downstream pathway activation such as JAK2 and AMPK suggesting a leptin-dependent role in fatty acid uptake and oxidation in WT-iPSC-CMs. On the contrary, leptin did not affect JAK2 and AMPK activation in LEPRΔ/Δ-iPSC-CMs. Culturing of (WT)-iPSC-CMs in F2+ medium demonstrated no significant difference in mitochondrial oxygen consumption, while slightly lower glycolysis and glycolytic capacity was observed. However, a leptin effect on fatty acid and glucose metabolism was observed in LEPR∆/∆-iPSC-CMs, which is independent from LEPR downstream regulation. To study the effect of high leptin levels, a medium mimicking some of the diabetic hallmarks, such as high glucose, high insulin, and high leptin levels, was used. Metabolic flexibility was observed in WT-iPSC-CMs in F3+ medium as showed by no difference in mitochondrial function in WT-iPSC-CMs in the presence or absence of high leptin. In contrast, LEPRΔ/Δ-iPSC-CMs in F3+ medium demostrated higher OCR compared to F2 medium, which is accompanied by lower glycolysis and glycolytic capacity, indicating the incapability of LEPRΔ/Δ-iPSC-CMs to use glucose as energy source, as measured by Seahorse analysis. Conclusion and outlook: Taken together, this study demonstrates the importance of leptin and LEPR at the late stage of CM maturation and the fundamental role of metabolic medium condition including physiological range of glucose and fatty acid to study the role of leptin in iPSC-CMs. In addition, LEPRΔ/Δ-iPSC-CMs in diabetic condition (F3+) represent a suitable model to investigate leptin-dependent cardiac metabolism, resulting in increased mitochondrial oxygen consumption and decreased glycolytic function, resembling the condition known in obesity-related T2DM patients. Further studies should focus on the regulation of the metabolic switch between glucose and fatty acid utilization in the absence of a functional LEPR. Understanding the contribution of leptin/LEPR signalling in human CM metabolism will shed light on novel therapeutic approaches to treat diabetic cardiomyopathy
Multi-objective Optimisation in Additive Manufacturing
Additive Manufacturing (AM) has demonstrated great potential to advance product
design and manufacturing, and has showed higher flexibility than conventional
manufacturing techniques for the production of small volume, complex and customised
components. In an economy focused on the need to develop customised and hi-tech
products, there is increasing interest in establishing AM technologies as a more efficient
production approach for high value products such as aerospace and biomedical
products.
Nevertheless, the use of AM processes, for even small to medium volume production
faces a number of issues in the current state of the technology. AM production is
normally used for making parts with complex geometry which implicates the
assessment of numerous processing options or choices; the wrong choice of process
parameters can result in poor surface quality, onerous manufacturing time and energy
waste, and thus increased production costs and resources. A few commonly used AM
processes require the presence of cellular support structures for the production of
overhanging parts. Depending on the object complexity their removal can be impossible
or very time (and resources) consuming.
Currently, there is a lack of tools to advise the AM operator on the optimal choice of
process parameters. This prevents the diffusion of AM as an efficient production
process for enterprises, and as affordable access to democratic product development for
individual users.
Research in literature has focused mainly on the optimisation of single criteria for AM
production. An integrated predictive modelling and optimisation technique has not yet
been well established for identifying an efficient process set up for complicated products which often involve critical building requirements. For instance, there are no
robust methods for the optimal design of complex cellular support structures, and most
of the software commercially available today does not provide adequate guidance on
how to optimally orientate the part into the machine bed, or which particular
combination of cellular structures need to be used as support. The choice of wrong
support and orientation can degenerate into structure collapse during an AM process
such as Selective Laser Melting (SLM), due to the high thermal stress in the junctions
between fillets of different cells.
Another issue of AM production is the limited parts’ surface quality typically generated
by the discrete deposition and fusion of material. This research has focused on the
formation of surface morphology of AM parts. Analysis of SLM parts showed that
roughness measured was different from that predicted through a classic model based on
pure geometrical consideration on the stair step profile. Experiments also revealed the
presence of partially bonded particles on the surface; an explanation of this phenomenon
has been proposed. Results have been integrated into a novel mathematical model for
the prediction of surface roughness of SLM parts. The model formulated correctly
describes the observed trend of the experimental data, and thus provides an accurate
prediction of surface roughness.
This thesis aims to deliver an effective computational methodology for the multi-
objective optimisation of the main building conditions that affect process efficiency of
AM production. For this purpose, mathematical models have been formulated for the
determination of parts’ surface quality, manufacturing time and energy consumption,
and for the design of optimal cellular support structures.
All the predictive models have been used to evaluate multiple performance and costs
objectives; all the objectives are typically contrasting; and all greatly affected by the
part’s build orientation. A multi-objective optimisation technique has been developed to visualise and identify
optimal trade-offs between all the contrastive objectives for the most efficient AM
production. Hence, this thesis has delivered a decision support system to assist the
operator in the "process planning" stage, in order to achieve optimal efficiency and
sustainability in AM production through maximum material, time and energy savings.EADS Airbus, Great Western Researc
Mapping road network communities for guiding disease surveillance and control strategies
Human mobility is increasing in its volume, speed and reach, leading to the
movement and introduction of pathogens through infected travelers. An
understanding of how areas are connected, the strength of these connections and
how this translates into disease spread is valuable for planning surveillance
and designing control and elimination strategies. While analyses have been
undertaken to identify and map connectivity in global air, shipping and
migration networks, such analyses have yet to be undertaken on the road
networks that carry the vast majority of travellers in low and middle income
settings. Here we present methods for identifying road connectivity
communities, as well as mapping bridge areas between communities and key
linkage routes. We apply these to Africa, and show how many highly-connected
communities straddle national borders and when integrating malaria prevalence
and population data as an example, the communities change, highlighting regions
most strongly connected to areas of high burden. The approaches and results
presented provide a flexible tool for supporting the design of disease
surveillance and control strategies through mapping areas of high connectivity
that form coherent units of intervention and key link routes between
communities for targeting surveillance.Comment: 11 pages, 5 figures, research pape
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