1,341 research outputs found

    Cavity assisted measurements of heat and work in optical lattices

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    We propose a method to experimentally measure the internal energy of a system of ultracold atoms trapped in optical lattices by coupling them to the fields of two optical cavities. We show that the tunnelling and self-interaction terms of the one-dimensional Bose-Hubbard Hamiltonian can be mapped to the field and photon number of each cavity, respectively. We compare the energy estimated using this method with numerical results obtained using the density matrix renormalisation group algorithm. Our method can be employed for the assessment of power and efficiency of thermal machines whose working substance is a strongly correlated many-body system.Comment: Accepted version in Quantum. Updates: New results for the work in quenching a Bose-Hubbard model; new references; v3 fixed doi links in references to make paper compliant with Quantu

    Four-year follow-up study in a NF1 Boy with a focal pontine hamartoma

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    Neurofibromatosis is a collective name for a group of genetic conditions in which benign tumours affect the nervous system. Type 1 is caused by a genetic mutation in the NF1 gene (OMIM 613113) and symptoms can vary dramatically between individuals, even within the same family. Some people have very mild skin changes, whereas others suffer severe medical complications. The condition usually appears in childhood and is diagnosed if two of the following are present: six or more café-au-lait patches larger than 1.5 cm in diameter, axillary or groin freckling, 2 or more Lisch nodules (small pigmented areas in the iris of the eye), 2 or more neurofibromas, optic pathway gliomas, bone dysplasia, and a first-degree family relative with Neurofibromatosis type 1. The pattern of inheritance is autosomal dominant, however, half of all NF1 cases are 'sporadic' and there is no family history. Neurofibromatosis type 1 is an extremely variable condition whose morbidity and mortality is largely dictated by the occurrence of the many complications that may involve any of the body systems. We describe a family affected by NF1 in whom genetic molecular analysis identified the same mutation in the son and father. Routine MRI showed pontine focal lesions in the eight-year-old son, though not in the father. We performed a four years follow-up study and at follow-up pontine hamartoma size remained unchanged in the son, and the father showed still no brain lesions, confirming thus an intra-familial phenotype variability

    The building information modeling for the retrofitting of existing buildings. A case study in the University of Cagliari.

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    Italy's very consistent buildings stock has become the major field for real estate investments and for the related projects and actions. The urge of working on built environment is however facing some crucial issues. The first is the lack of documentation on the construction history and on the real constructive layout of existing buildings (in terms of components, installations, plants, etc.). The second is the poor activity in surveying their current status, with reference to use (energy behaviour, real consumptions, etc.) and maintenance (conservation status, previous maintenance works, compliance with current regulations, etc.). These obstacles cause a deep inefficiency in the planning, programming and controlling of requalification and/or refunctionalisation works. Starting from these assumptions, this paper shows the findings of a research shared by the Politecnico of Milan and the Department of Civil and Environmental Engineering and Architecture of the University of Cagliari. It is aimed at testing the use of building information modeling (BIM) to structure the necessary knowledge to evaluate intervention scenarios. The research is focused on the Mandolesi Pavilion of the University of Cagliari, designed by Enrico Mandolesi. It is a highly stimulating architectural object because it incorporates values that require a conservative approach, but at the same time, like most contemporary buildings, it was designed and built for innovation and not for “long duration”. The work has actually led to the realization of a BIM model of the case study. It represents the first prefiguration of an approach that develops from construction history and continues with advanced diagnostics on the statical and energy performances of the building. The model formalizes knowledge and information on a significant building, aimed at its management. It allows also the setting of intervention scenarios that can be evaluated with real-time simulations of cost, time and ROI

    Evolutionary dynamics in vascularised tumours under chemotherapy : mathematical modelling, asymptotic analysis and numerical simulations

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    We consider a mathematical model for the evolutionary dynamics of tumour cells in vascularised tumours under chemotherapy. The model comprises a system of coupled partial integro-differential equations for the phenotypic distribution of tumour cells, the concentration of oxygen and the concentration of a chemotherapeutic agent. In order to disentangle the impact of different evolutionary parameters on the emergence of intra-tumour phenotypic heterogeneity and the development of resistance to chemotherapy, we construct explicit solutions to the equation for the phenotypic distribution of tumour cells and provide a detailed quantitative characterisation of the long-time asymptotic behaviour of such solutions. Analytical results are integrated with numerical simulations of a calibrated version of the model based on biologically consistent parameter values. The results obtained provide a theoretical explanation for the observation that the phenotypic properties of tumour cells in vascularised tumours vary with the distance from the blood vessels. Moreover, we demonstrate that lower oxygen levels may correlate with higher levels of phenotypic variability, which suggests that the presence of hypoxic regions supports intra-tumour phenotypic heterogeneity. Finally, the results of our analysis put on a rigorous mathematical basis the idea, previously suggested by formal asymptotic results and numerical simulations, that hypoxia favours the selection for chemoresistant phenotypic variants prior to treatment. Consequently, this facilitates the development of resistance following chemotherapy.Publisher PDFPeer reviewe

    "Electro-clinical Syndromes" with onset in Paediatric Age. the highlights of the clinical-EEG, genetic and therapeutic advances

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    The genetic causes underlying epilepsy remain largely unknown, and the impact of available genetic data on the nosology of epilepsy is still limited. Thus, at present, classification of epileptic disorders should be mainly based on electroclinical features. Electro-clinical syndrome is a term used to identify a group of clinical entities showing a cluster of electro-clinical characteristics, with signs and symptoms that together define a distinctive, recognizable, clinical disorder. These often become the focus of treatment trials as well as of genetic, neuropsychological, and neuroimaging investigations. They are distinctive disorders identifiable on the basis of a typical age onset, specific EEG characteristics, seizure types, and often other features which, when taken together, permit a specific diagnosis which, in turn, often has implications for treatment, management, and prognosis. Each electro-clinical syndrome can be classified according to age at onset, cognitive and developmental antecedents and consequences, motor and sensory examinations, EEG features, provoking or triggering factors, and patterns of seizure occurrence with respect to sleep. Therefore, according to the age at onset, here we review the more frequently observed paediatric electro-clinical syndrome from their clinical-EEG, genetic and therapeutic point of views

    DIRE "NO!" ALLA LEGGE. L'obiezione di coscienza: profili storici, teorici e giuridici.

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    Il presente lavoro affronta la tematica classica, e sempre attuale, della disobbedienza alla legge, focalizzando in un secondo momento l’attenzione sulla figura dell’obiezione di coscienza. Il primo capitolo introduce alcune definizioni: destrutturando analiticamente l’ampio genus del diritto di resistenza, si ottiene una classificazione degli atteggiamenti che i consociati possono avere nei confronti della legge. Tra questi vi sono due figure molto simili: la disobbedienza civile e l’obiezione di coscienza, che gran parte degli autori, soprattutto americani, hanno cercato di distinguere, individuandone le peculiarità. Attualmente, l’evoluzione subita dall’obiezione di coscienza ed il diverso contesto politico e giuridico dell’Europa continentale rendono sempre più sfumate le differenze tra queste due sottocategorie della resistenza. In particolare, l’obiezione ha ad oggetto una coscienza lato sensu intesa, comprendente anche una finalità politica, che condivide con la disobbedienza civile. Il secondo capitolo ripercorre la storia del diritto-dovere di resistenza, a partire dalle tragedie greche di Antigone e Socrate, per giungere al periodo dell’Assemblea costituente italiana. Successivamente, ci si confronta con un interrogativo molto spinoso che rappresenta uno dei nuclei centrali della tesi: l’esistenza di uno spazio residuale per la disobbedienza alla legge nelle democrazie contemporanee e la necessità di un’obbedienza consapevole e responsabile. Il terzo capitolo apre la seconda parte della trattazione. Si è scelto di occuparci della forma di resistenza più discussa: l’obiezione di coscienza. Si dà atto degli sforzi della dottrina nell’individuarne il fondamento giuridico sia costituzionale sia sovranazionale; si riportano le teorie che si sono susseguite relativamente al suo funzionamento negli Stati costituzionali, nonché i limiti necessari per un suo riconoscimento nell’ordinamento. Questa ricostruzione viene svolta alla luce dell’idea che permea questo lavoro: la coscienza è una realtà che non può fare a meno della sua dimensione relazionale. Di conseguenza, uno dei limiti non può che essere legato alla profonda natura della coscienza: l’obiezione non potrà negare l’altro, per cui non possono essere rivendicate obiezioni che, in nome di valori personali ritenuti superiori, incidono sui beni fondamentali della persona, quali la vita, l’integrità fisica. Inoltre, a partire dalla proposta di alcuni autori di evitare il conflitto di coscienza mediante l’astensione del soggetto dal praticare certe professioni nel quale esso può sorgere, ci si è chiesti se veramente eliminare il conflitto sia la soluzione migliore. Il quarto capitolo studia alcune ipotesi di obiezione di coscienza in materia di bioetica allo scopo di fornire uno spunto per analizzare alcune tematiche particolarmente delicate (tra cui l’inizio della vita umana, l’eugenetica e le velate forme di selezione genetica che si possono nascondere dietro ad alcune tecniche scientifiche). Questa parte del lavoro non ha come obiettivo quello di fornire risposte, quanto di suscitare domande. L’ultimo capitolo rassegna alcune conclusioni (in realtà si tratta di ulteriori riflessioni): nel tentativo di “prendere i conflitti sul serio”, la risposta non può consistere nel soffocamento a priori delle forme di opposizione alle scelte del potere, anche qualora questo rappresenti la maggioranza. L’obiezione di coscienza può rappresentare l’opportunità per confrontarsi con il valore da questa tutelato e per interrogarsi sulla strada che una determinata società sta imboccando

    Body composition estimation from selected slices:equations computed from a new semi-automatic thresholding method developed on whole-body CT scans

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    Background Estimating volumes and masses of total body components is important for the study and treatment monitoring of nutrition and nutrition-related disorders, cancer, joint replacement, energy-expenditure and exercise physiology. While several equations have been offered for estimating total body components from MRI slices, no reliable and tested method exists for CT scans. For the first time, body composition data was derived from 41 high-resolution whole-body CT scans. From these data, we defined equations for estimating volumes and masses of total body AT and LT from corresponding tissue areas measured in selected CT scan slices. Methods We present a new semi-automatic approach to defining the density cutoff between adipose tissue (AT) and lean tissue (LT) in such material. An intra-class correlation coefficient (ICC) was used to validate the method. The equations for estimating the whole-body composition volume and mass from areas measured in selected slices were modeled with ordinary least squares (OLS) linear regressions and support vector machine regression (SVMR). Results and Discussion The best predictive equation for total body AT volume was based on the AT area of a single slice located between the 4th and 5th lumbar vertebrae (L4-L5) and produced lower prediction errors (|PE| = 1.86 liters, %PE = 8.77) than previous equations also based on CT scans. The LT area of the mid-thigh provided the lowest prediction errors (|PE| = 2.52 liters, %PE = 7.08) for estimating whole-body LT volume. We also present equations to predict total body AT and LT masses from a slice located at L4-L5 that resulted in reduced error compared with the previously published equations based on CT scans. The multislice SVMR predictor gave the theoretical upper limit for prediction precision of volumes and cross-validated the results
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