3,829 research outputs found

    Viscoelasticity and Stokes-Einstein relation in repulsive and attractive colloidal glasses

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    We report a numerical investigation of the visco-elastic behavior in models for steric repulsive and short-range attractive colloidal suspensions, along different paths in the attraction-strength vs packing fraction plane. More specifically, we study the behavior of the viscosity (and its frequency dependence) on approaching the repulsive glass, the attractive glass and in the re-entrant region where viscosity shows a non monotonic behavior on increasing attraction strength. On approaching the glass lines, the increase of the viscosity is consistent with a power-law divergence with the same exponent and critical packing fraction previously obtained for the divergence of the density fluctuations. Based on mode-coupling calculations, we associate the increase of the viscosity with specific contributions from different length scales. We also show that the results are independent on the microscopic dynamics by comparing newtonian and brownian simulations for the same model. Finally we evaluate the Stokes-Einstein relation approaching both glass transitions, finding a clear breakdown which is particularly strong for the case of the attractive glass.Comment: 12 pages; sent to J. Chem. Phy

    Identification of Contradictory Patterns in Experimental Datasets for the Development of Models for Electrical Cables Diagnostics

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    International audienceThe state of health of an electrical cable may be difficult to know, without destructive or very expensive tests. To overcome this, partial discharge (PD) measurements have been proposed as a relatively economic and simple-to-apply experimental technique for retrieving information on the state of health of an electrical cable. The retrieval is based on a relationship between PD measurements and the health of the cable. Given the difficulties in capturing such relationship by analytical models, empirical modeling techniques based on experimental data have been propounded. In this view, a set of PD measurements have been collected by Enea Ricerca sul Sistema Elettrico-ERSE during past campaigns, for building a diagnostic system of electrical cable health state. These experimental data may contain contradictory information which remarkably reduces the performance of the state classifier, if not a priori identified and possibly corrected. In the present paper, a novel technique based on the Adaboost algorithm is proposed for identifying contradictory PD patterns within an a priori analysis aimed at improving the diagnostic performance. Adaboost is a bootstrap-inspired, ensemble-based algorithm which has been effectively used for addressing classification problems

    Entropic force, noncommutative gravity and ungravity

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    After recalling the basic concepts of gravity as an emergent phenomenon, we analyze the recent derivation of Newton's law in terms of entropic force proposed by Verlinde. By reviewing some points of the procedure, we extend it to the case of a generic quantum gravity entropic correction to get compelling deviations to the Newton's law. More specifically, we study: (1) noncommutative geometry deviations and (2) ungraviton corrections. As a special result in the noncommutative case, we find that the noncommutative character of the manifold would be equivalent to the temperature of a thermodynamic system. Therefore, in analogy to the zero temperature configuration, the description of spacetime in terms of a differential manifold could be obtained only asymptotically. Finally, we extend the Verlinde's derivation to a general case, which includes all possible effects, noncommutativity, ungravity, asymptotically safe gravity, electrostatic energy, and extra dimensions, showing that the procedure is solid versus such modifications.Comment: 8 pages, final version published on Physical Review

    High-grade vaginal intraepithelial neoplasia and risk of progression to vaginal cancer. a multicentre study of the Italian Society of Colposcopy and Cervico-Vaginal Pathology (SICPCV)

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    OBJECTIVE: The aim of this study was to analyse the women with high grade vaginal intraepithelial neoplasia (HG-VaIN), in order to identify a subset of women at higher risk of progression to invasive vaginal cancer. MATERIALS AND METHODS: The medical records of all the women diagnosed with HG-VaIN, and subsequently treated, from January 1995 to December 2013 were analyzed in a multicentre retrospective case series. The rate of progression to invasive vaginal cancer and the potential risk factors were evaluated. RESULTS: 205 women with biopsy diagnosis of HG-VaIN were considered, with a mean follow up of 57 months (range 4-254 months). 12 cases of progression to vaginal squamocellular cancer were observed (5.8%), with a mean time interval from treatment to progression of 54.6 months (range 4-146 months). The rate of progression was significantly higher in women diagnosed with VaIN3 compared with VaIN2 (15.4% vs. 1.4%, p < 0.0001). Women with HG-VaIN and with previous hysterectomy showed a significantly higher rate of progression to invasive vaginal cancer compared to non-hysterectomised women (16.7% vs. 1.4%, p < 0.0001). A higher risk of progression for women with VaIN3 and for women with previous hysterectomy for cervical HPV-related disease was confirmed by multivariable logistic regression analysis. CONCLUSIONS: A higher rate of progression to vaginal cancer was reported in women diagnosed with VaIN3 on biopsy and in women with previous hysterectomy for HPV-related cervical disease. These patients should be considered at higher risk, thus a long lasting and accurate follow up is recommended

    Robotic-assisted thoracoscopy thymectomy for juvenile myasthenia gravis

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    Abstract Introduction Juvenile myasthenia gravis (JMG) is a rare debilitating and potentially fatal autoimmune disease, with unclearify pathogenesis. Surgical immunomodulation with thymectomy has been repeatedly demonstrated to be a safe and effective treatment for JMG in both adult and pediatric patients. In the last few years, minimally invasive approach and above all robotic assisted thoracoscopy, replaced sternotomy which is widely used in adult patients. We report our experience in a case of robot-assisted thoracoscopic thymectomy approach in a 12 years old boy for juvenile myasthenia gravis (JMG). Case report Procedure was performed with the Da Vinci surgical robot (Xi) using left-sided approach. Left lung was kept out from mechanic ventilation. A 8 mm port for the 3-D camera was introduced on the V intercostal space on the anterior axillary line. Others two 8mm thoracic ports were placed under vision after the induction of a low-pressure pneumothorax, respectively on the midaxillary line on the III intercostal space and on the parasternal space on the V intercostal space. Bulk resection of gland was made using Maryland grasper and Harmonic scalpel, starting at level of the left pericardiophrenic angle and continuing cranially. Thymus was unstick from the posterior face of the sternum until the right pleura releasing lower thymic horns. After that, controlateral right-side thymectomy was continued into the neck to include the upper horns and finally it was removed with an endocatch bag. Histopathological examination showed a benign thymic hyperplasia. There were no perioperative and postoperative complications. The discharge was on IV post-operative day. After thymectomy, patient reported an improvement in symptoms and stopped medical therapy with pyridostigmine. Conclusions VATS and Robotic thoracoscopic thymectomy have increasingly taken hold in recent years. The surgical treatment offered to patient an improvement in clinical status. Surgery by robotic assistance has demonstrable advantages, including three-dimensional visualization and articulating instruments. Left lateral approach provided excellent visualization of the thymic veins, anonymous vases and phrenic nerves. Three-dimensional visualization as well as articulating arms greatly facilitated the dissection compared with standard thoracoscopic technique. In Literature very few series of robotic approach for surgical treatment of JMG in children are reported, for these reasons further studies are needed

    The rest-frame KK-band luminosity function of galaxies in clusters to z=1.3z=1.3

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    We derive the rest-frame KK-band luminosity function for galaxies in 32 clusters at 0.6<z<1.30.6 < z < 1.3 using deep 3.6μ3.6\mum and 4.5μ4.5\mum imaging from the Spitzer Space Telescope InfraRed Array Camera (IRAC). The luminosity functions approximate the stellar mass function of the cluster galaxies. Their dependence on redshift indicates that massive cluster galaxies (to the characteristic luminosity MK∗M^*_K) are fully assembled at least at z∼1.3z \sim 1.3 and that little significant accretion takes place at later times. The existence of massive, highly evolved galaxies at these epochs is likely to represent a significant challenge to theories of hierarchical structure formation where such objects are formed by the late accretion of spheroidal systems at z<1z < 1.Comment: Accepted for publication in AJ; includes data table of k-correction

    Tuning electrical properties of hierarchically assembled Al-doped ZnO nanoforests by room temperature Pulsed Laser Deposition

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    Large surface area, 3D structured transparent electrodes with effective light management capability may represent a key component in the development of new generation optoelectronic and energy harvesting devices. We present an approach to obtain forest-like nanoporous/hierarchical Al-doped ZnO conducting layers with tunable transparency and light scattering properties, by means of room temperature Pulsed Laser Deposition in a mixed Ar:O2 atmosphere. The composition of the background atmosphere during deposition can be varied to modify stoichiometry-related defects, and therefore achieve control of electrical and optical properties, while the total background pressure controls the material morphology at the nano- and mesoscale and thus the light scattering properties. This approach allows to tune electrical resistivity over a very wide range (10^-1 - 10^6 Ohm*cm), both in the in-plane and cross-plane directions. Optical transparency and haze can also be tuned by varying the stoichiometry and thickness of the nano-forests

    Extremely low-frequency electromagnetic fields do not affect DNA damage and gene expression profiles of yeast and human lymphocytes

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    We studied the effects of extremely low-frequency (50 Hz) electromagnetic fields (EMFs) on peripheral human blood lymphocytes and DBY747 Saccharomyces cerevisiae. Graded exposure to 50 Hz magnetic flux density was obtained with a Helmholtz coil system set at 1, 10 or 100 microT for 18 h. The effects of EMFs on DNA damage were studied with the single-cell gel electrophoresis assay (comet assay) in lymphocytes. Gene expression profiles of EMF-exposed human and yeast cells were evaluated with DNA microarrays containing 13,971 and 6,212 oligonucleotides, respectively. After exposure to the EMF, we did not observe an increase in the amount of strand breaks or oxidated DNA bases relative to controls or a variation in gene expression profiles. The results suggest that extremely low-frequency EMFs do not induce DNA damage or affect gene expression in these two different eukaryotic cell systems

    Trend of decreasing length of cervical cone excision during the last 20 years

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    OBJECTIVE: The aim of the present investigation was to evaluate the cervical conizations performed in the last 20 years in a single institution, with a particular interest in analyzing the trend of the length of cone excisions.PATIENTS AND METHODS: A retrospective cohort study of women who underwent a CO2-laser cervical conization between January 1996 and December 2015. Cytological abnormalities on referral pap smear, colposcopic findings and pertinent clinical and socio-demographic characteristics of each woman were collected. In particular, the length of cone specimen was evaluated, taking into account all the factors potentially influencing the length of excision.RESULTS: A total of 1270 women who underwent cervical conization from January 1996 to December 2015 were included in the analysis. A mean cone length of 15.1 \ub1 5.7 mm was reported, and we observed a significant decrease in the length of cone excisions over the whole study period. Age (rpartial = 0.1543, p < 0.0001), see & treat procedure (rpartial = -0.1945, p < 0.0001) and grade II colposcopic findings (rpartial = 0.1540, p < 0.0001) were significantly associated with the length of cone excision on multivariate analysis.CONCLUSIONS: In the last 20 years, a significant decrease in the length of cone excision was observed. In our opinion, this can be due to the acquired awareness by the gynecologists of the potential disadvantages of wide cone excision in term of adverse obstetric outcomes in future pregnancies

    A global map of terrestrial habitat types

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    Funder: NatureMap (https://naturemap.earth/) through Norway&apos;s International Climate and Forest Initiative (NICFI)Abstract: We provide a global, spatially explicit characterization of 47 terrestrial habitat types, as defined in the International Union for Conservation of Nature (IUCN) habitat classification scheme, which is widely used in ecological analyses, including for quantifying species’ Area of Habitat. We produced this novel habitat map for the year 2015 by creating a global decision tree that intersects the best currently available global data on land cover, climate and land use. We independently validated the map using occurrence data for 828 species of vertebrates (35152 point plus 8181 polygonal occurrences) and 6026 sampling sites. Across datasets and mapped classes we found on average a balanced accuracy of 0.77 (+¯0.14 SD) at Level 1 and 0.71 (+¯0.15 SD) at Level 2, while noting potential issues of using occurrence records for validation. The maps broaden our understanding of habitats globally, assist in constructing area of habitat refinements and are relevant for broad-scale ecological studies and future IUCN Red List assessments. Periodic updates are planned as better or more recent data becomes available
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