440 research outputs found

    Phase rigidity breaking in open Aharonov-Bohm ring coupled to a cantilever

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    The conductance and the transmittance phase shifts of a two-terminal Aharonov-Bohm (AB) ring are analyzed in the presence of mechanical displacements due to coupling to an external can- tilever. We show that phase rigidity is broken, even in the linear response regime, by means of inelastic scattering due to phonons. Our device provides a way of observing continuous variation of the transmission phase through a two-terminal nano-electro-mechanical system (NEMS). We also propose measurements of phase shifts as a way to determine the strength of the electron-phonon coupling in NEMS.Comment: 7 pages, 8 figure

    Models for Identifying Structures in the Data: A Performance Comparison

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    This paper reports on the unsupervised analysis of seismic signals recorded in Italy, respectively on the Vesuvius volcano, located in Naples, and on the Stromboli volcano, located North of Eastern Sicily. The Vesuvius dataset is composed of earthquakes and false events like thunders, man-made quarry and undersea explosions. The Stromboli dataset consists of explosion-quakes, landslides and volcanic microtremor signals. The aim of this paper is to apply on these datasets three projection methods, the linear Principal Component Analysis (PCA), the Self-Organizing Map (SOM), and the Curvilinear Component Analysis (CCA), in order to compare their performance. Since these algorithms are well known to be able to exploit structures and organize data providing a clear framework for understanding and interpreting their relationships, this work examines the category of structural information that they can provide on our specific sets. Moreover, the paper suggests a breakthrough in the application area of the SOM, used here for clustering different seismic signals. The results show that, among the three above techniques, SOM better visualizes the complex set of high-dimensional data discovering their intrinsic structure and eventually appropriately clustering the different signal typologies under examination, discriminating the explosionquakes from the landslides and microtremor recorded at the Stromboli volcano, and the earthquakes from natural (thunders) and artificial (quarry blasts and undersea explosions) events recorded at the Vesuvius volcano

    Recuperación edilicia integral, restauración y puesta en valor arquitectónico de la Basílica de Guadalupe de la ciudad de Santa Fe

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    El presente trabajo refleja la combinación de una experiencia de obra, cimentada en investigaciones de campo, y corresponde a la intervención en un edificio con patología estructural severa.- La Basílica de Guadalupe ubicada en Santa Fe (ciudad), posee estilo neogótico bajo, construida en 1905, en mampostería de ladrillos desde las cimentaciones. Con una planimetría en forma de cruz de aproximadamente 2.200 m2 (nave central y dos laterales). Posee cubiertas combinadas de chapas sobre estructura de hierro y losas de bovedilla apoyadas en muros. La carga muerta estimada para transferir a las bases es aproximadamente de 8.600 toneladas.- Ante un cuadro de afectación severo, evidenciado en la manifestación de patologías típicas de fallas en la cadena de transferencia de cargas por asentamientos diferenciados, punzonamientos y pérdida de verticalidad en muros, mostrando deformaciones en pisos y fisuraciones en muros y cielorrasos al nivel de producirse el colapso parcial de un sector de cielorraso abovedado (en diciembre de 2004), fue necesario diseñar acciones correctivas para la recuperación de la condición de seguridad. Se elaboró como primera medida un diagnóstico de situación, evaluación estructural mediante. Para ello se llevaron a cabo una serie de instancias apuntando a determinar las causas del problema (etiología) y la magnitud de afectación. La evaluación contempló en general observación ocular, estudios de suelos y control de deformaciones diferido en el tiempo. Se pudo diagnosticar como causal básico del cuadro de afectación a la pérdida de capacidad portante por saturación del suelo de fundación con erosión de finos (limos, arcillas y coloides) por ingreso directo no contemplado de aguas filtrantes de los sistemas de desagües pluviales perimetrales del edificio en combinación fuertemente desfavorable con un emisario de la red pública pluvial que presentó fallas de estanqueidad. El control de deformaciones de mediciones sucesivas y periódicas en el tiempo permitió verificar la presencia de un proceso activo en la estructura con un patrón creciente con incremento de espesores de fisuras.- Con los resultados obtenidos, se diseñaron acciones correctivas: reconstrucción de la red pluvial interna, recalce de cimientos mediante la transferencia de cargas del plano de fundación hasta un estrato de mayor resistencia; y anclajes de muros afectados por fisuras. El recalce se realizó mediante la construcción de MP IRS (micropilotes con Inyección Repetitiva y Selectiva) y el refuerzo de muros incorporando tensores pasivos horizontales dentro del espesor de los mismos en tres niveles diferentes.- La ejecución de MP se realizó entre diciembre 2005 y julio 2007 (cambio de tecnología de ejecución mediante sobre la marcha); mientras que los tensores horizontales, se ejecutaron entre setiembre 2007 y abril 2008.- Paralelamente para monitorear la evolución y analizar la eficiencia de los refuerzos en forma global en la estructura, se diseñó e implementó un sistema referencial de control de asentamientos colocando escalas perimetrales exteriores, y de fisuras, con comparadores interiores (con mediciones efectuadas trimestralmente durante el primer año y semestralmente en el segundo).- Esta contribución se centró en aspectos relativos a las etapas de ejecución del micropilotaje por entender que allí es donde se puede brindar el aporte más interesante para este Congreso, dado que habitualmente se basa en técnicas que aplican pautas teóricas que requieren ajustes según las particularidades de cada caso. - Del monitoreo realizado se infiere un comportamiento que marca una clara tendencia general en los movimientos relativos decreciente asintóticamente, reflejo de la toma de carga de los micropilotes y la transferencia paulatina, con adecuamiento de la estructura edilicia a nuevas condiciones de cimentación y refuerzos. Alcanzada ésta y recompuesta la cadena de transferencia de cargas queda habilitada la factibilidad de iniciar la siguiente etapa de restauración y puesta en valor arquitectónico de la Basílica.-Tópico 5: Intervenciones en construcciones con patologías estructurales y aplicación de refuerzos

    Synergic use of botulinum toxin injection and radial extracorporeal shockwave therapy in multiple sclerosis spasticity

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    Background and aim: In Multiple Sclerosis (MS) spasticity worsens the patient’s quality of life. Botulinum NeuroToxin TypeA (BoNT-A) is extensively used in focal spasticity, frequently combined with physical therapies. Radial extracorporeal shock waves (rESW) were already used in association with BoNTA. Considering that loss of efficacy and adverse events are determinants of BoNT-A treatment interruption, this study aimed to evaluate the possibility to prolong BoNT-A’s effect by using rESW in MS focal spasticity. Methods: Sixteen MS patients with spasticity of triceps surae muscles were first subjected to BoNT-A therapy and, four months later, to 4 sections of rESWT. Patients were evaluated before, 30, 90 days after the end of the treatments, by using Modified Ashworth Scale (MAS), Modified Tardieu Scale (MTS), and kinematic analysis of passive and active ankle ROM. Results: BoNT-A determined a significant reduction of spasticity evaluated by MAS with a reduction of positive effects after 4months (p<0.05); MTS highlighted the efficacy only 90 days after injection (p<0.05). rESWT decreased MAS values at the end and 30 days later the treatment (p<0.01); MTS values showed instead a prolonged effect (p<0.01). BoNT-A determined a gain of passive and active ankle ROM, persisting along with treatment and peaking the maximum value after rESWT (p<0.05). Conclusions: rESWT can prolong BoNT-A effect inducing a significant reduction of spasticity and improvement in passive and active ankle ROM in MS patients. The use of rESWT following BoNT-A injection is useful to avoid some limitations and to prolong the therapeutic effects of BoNT-A therapy. (www.actabiomedica.it)

    Congenital pouch colon associated to a cloaca malformation in a syndromic newborn: A case report

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    Introduction: Congenital pouch colon (CPC) is a rare intestinal anomaly usually associated with an anorectal malformation (ARM). Because of its low incidence, there are no guidelines on the correct treatment. We report the step-by-step management and challenging surgery of a newborn with CPC and cloaca to ensure the patient's best quality of life possible. Case presentation: We describe a case of type II CPC associated with a complex cloaca with a retrovesical didelphus uterus in a 1530g preterm syndromic female. A preoperative cystoscopy identified a urogenital sinus with an anterior bladder and a posterior vagina. The abdominal exploration done on day 1 showed a dilated CPC with the cecum ending in a large structure extending toward the bladder, and a proximal diverting ileostomy was created. Eight months later, the CPC was mobilized, and the common wall of the bladder and the pouch colon was excised. The 8-cm colonic pouch was tabularized by a triangle resection resulting in a colonic tube used to create a colostomy. Because of the syndromic nature of the patient, the consensus has been not to proceed with the urogenital reconstruction and the ileo-anal pull-through. Conclusion: CPC malformations should be suspected in the case of a single perineal orifice. There is no consensus about the best surgical approach to CPC. The operative reconstruction must be tailored to each patient in order to ensure the best possible quality of life

    Sodium Cyclopentadienide as a New Type of Electrolyte for Sodium Batteries

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    Owing to the low cost and high abundance of sodium, sodium‐based batteries, especially those employing metallic sodium anodes, are considered for post‐lithium energy storage. In order to develop high‐performance and long‐lasting sodium‐metal batteries, however, the reversible Na‐metal stripping and plating challenge must be addressed. Most organic electrolytes suffer from non‐uniform and continuous formation of the solid electrolyte interphase as well as unfavorable dendritic growth. The use of sodium cyclopentadienide dissolved in tetrahydrofuran as the electrolyte reveals an improved reversibility of sodium dissolution and electrodeposition combined with an electrochemical stability window of around 2.2 V vs. Na/Na+ and an ionic conductivity of 1.36 mS cm−1 at 25 °C. Furthermore, the plated electrodes showed a remarkable morphology of the Na deposits, that is, no dendrite formation, whereby the above‐mentioned electrolyte could overcome the aforementioned cycling issues, thus suggesting suitability for further studies

    Working Memory, Jumping to Conclusions and Emotion Recognition: a Possible Link in First Episode Psychosis (Fep)

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    Introduction A large body of literature has demonstrated that people affected by psychotic disorders show deficits in working memory, in Emotion Recognition (ER) and in data-gathering to reach a decision (Jumping To Conclusions - JTC). Aims To investigate a possible correlation between working memory, JTC and ER in FEP. Methods 41 patients and 89 healthy controls completed assessments of working memory using WAIS shortened version, JTC using the 60:40 Beads Task and ER using Degraded Facial Affect Recognition Task. Results According to the literature, cases had poorer performance in working memory tasks (Digit Span: \u3bc7,72 [ds=2,98] vs \u3bc10,14 [ds=3,10], U=865,00, p=0,00; Digit Symbol: \u3bc5,36 [ds=2,43] vs \u3bc10,05 [ds=3,10], U=455,50, p=0,00; Arithmetic: \u3bc5,46 [ds=2,76] vs \u3bc8,74 [ds=3,24], U=865,50, p=0,00; Block Design: \u3bc4,82 [ds=2,72] vs \u3bc7,60 [ds=3,18], U=912,00, p=0,00), in Beads Task (81,6% vs 51,1%, \u3c72=10,27, p=0,001, \u3bc2,53 [ds=3,57] vs \u3bc4,23 [ds=4,77], U=1171,00, p=0,006) and in DFAR (total errors: \u3bc21,62 [ds=7,43] vs \u3bc16,58 [ds=8,69], U=554,50, p=0,002). Furthermore working memory tasks in cases group correlated significantly with JTC (Digit Span: rrho=0,276, p=0,003; Digit Symbol: rrho=0,275, p=0,002; Arithmetic: rrho=0,265, p=0,003; Block Design: rrho=0,292, p=0,001), but only Digit Span with ER (rrho=-0,239; p=0,021). In addition, we found that JTC and ER were significantly associated (rrho=-0,281; p=0,004). Conclusions Data show that working memory impairments, JTC style and dysfunctions in the facial emotions recognition are phenomena strongly correlated in the group of patients. Preliminary results suggest the importance of early rehabilitation as the impairments detected may lead to difficulties in social and relational adaptation in psychotic patients

    Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment

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    GEMS (Gamma Energy Marine Spectrometer) is a prototype of an autonomous radioactivity sensor for underwater measurements, developed in the framework for a development of a submarine telescope for neutrino detection (KM3NeT Design Study Project). The spectrometer is highly sensitive to gamma rays produced by 40K decays but it can detect other natural (e.g., 238U,232Th) and anthropogenic radio-nuclides (e.g., 137Cs). GEMS was firstly tested and calibrated in the laboratory using known sources and it was successfully deployed for a long-term (6 months) monitoring at a depth of 3200 m in the Ionian Sea (Capo Passero, offshore Eastern Sicily). The instrument recorded data for the whole deployment period within the expected specifications. This monitoring provided, for the first time, a continuous time-series of radioactivity in deep-sea.In press4.5. Studi sul degassamento naturale e sui gas petroliferiJCR Journalope
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