470 research outputs found

    Quantum key distribution using polarized coherent states

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    We discuss a continuous variables method of quantum key distribution employing strongly polarized coherent states of light. The key encoding is performed using the variables known as Stokes parameters, rather than the field quadratures. Their quantum counterpart, the Stokes operators S^i\hat{S}_i (i=1,2,3), constitute a set of non-commuting operators, being the precision of simultaneous measurements of a pair of them limited by an uncertainty-like relation. Alice transmits a conveniently modulated two-mode coherent state, and Bob randomly measures one of the Stokes parameters of the incoming beam. After performing reconciliation and privacy amplification procedures, it is possible to distill a secret common key. We also consider a non-ideal situation, in which coherent states with thermal noise, instead of pure coherent states, are used for encoding.Comment: Inclusion of a discussion about noise not controlled by Eve; inclusion of a figure. A simplified version of this paper was submitted to a Conference in Brazil (XXVII ENFMC) in 16/02/200

    Quantum Key Distribution using Continuous-variable non-Gaussian States

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    In this work we present a quantum key distribution protocol using continuous-variable non-Gaussian states, homodyne detection and post-selection. The employed signal states are the Photon Added then Subtracted Coherent States (PASCS) in which one photon is added and subsequently one photon is subtracted. We analyze the performance of our protocol, compared to a coherent state based protocol, for two different attacks that could be carried out by the eavesdropper (Eve). We calculate the secret key rate transmission in a lossy line for a superior channel (beam-splitter) attack, and we show that we may increase the secret key generation rate by using the non-Gaussian PASCS rather than coherent states. We also consider the simultaneous quadrature measurement (intercept-resend) attack and we show that the efficiency of Eve's attack is substantially reduced if PASCS are used as signal states.Comment: We have included an analysis of the simultaneous quadrature measurement attack plus 2 figures; we have also clarified some point

    Optimization of Anti-SARS-CoV-2 Treatments Based on Curcumin, Used Alone or Employed as a Photosensitizer.

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    Curcumin, the bioactive compound of the spice Curcuma longa, has already been reported as a potential COVID-19 adjuvant treatment due to its immunomodulatory and anti-inflammatory properties. In this study, SARS-CoV-2 was challenged with curcumin; moreover, curcumin was also coupled with laser light at 445 nm in a photodynamic therapy approach. Curcumin at a concentration of 10 ÎĽM, delivered to the virus prior to inoculation on cell culture, inhibited SARS-CoV-2 replication (reduction >99%) in Vero E6 cells, possibly due to disruption of the virion structure, as observed using the RNase protection assay. However, curcumin was not effective as a prophylactic treatment on already-infected Vero E6 cells. Notably, when curcumin was employed as a photosensitizer and blue laser light at 445 nm was delivered to a mix of curcumin/virus prior to the inoculation on the cells, virus inactivation was observed (>99%) using doses of curcumin that were not antiviral by themselves. Photodynamic therapy employing crude curcumin can be suggested as an antiviral option against SARS-CoV-2 infection

    Influence of lifestyle habits, nutritional status and insulin resistance in NAFLD

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    Non alcoholic fatty liver disease (NAFLD) is associated with obesity, diabetes and insulin resistance (IR). The aim of our study was to assess the relationship between IR, anthropometry, lifestyle habits, resting energy expenditure (REE) and degree of fatty liver at ultrasound in 48 overweight patients with NAFLD as compared to 24 controls without fatty liver, matched for age. Nutritional status, alcohol intake and physical activity were assessed by skinfold thickness measurements, a 7-day diary, and SenseWear armband (SWA). REE was assessed by both SWA (REE-SWA) and a Vmax metabolic cart (REE-Vmax). Fatty liver was measured by US and the Doppler Power Index was calculated. IR was assessed using the HOMA index. There was significant correlation between waist circumference, HOMA, Doppler power index and fatty liver grade at US. Multivariate analysis showed that alteration of waist circumference, Doppler power index, and HOMA were the major significant predictors of fatty liver. Our data demonstrated a significant association between NAFLD and central adiposity and IR

    Source characterization guidelines for noise mapping of port areas

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    Maritime transport for both passengers and freight is continuously increasing and, consequently, the global attention toward its sustainability is growing. Ships offer advantages in terms of environmental impact compared to other transportation systems but the increasing traffic volume is expected to increase pollutants. Noise produced in port areas has been neglected for too long, until the INTERREG Maritime programme Italy-France 2014\u20132020 has brought to light how citizen complaints are emerging for some of the main ports in the Mediterranean. However, port noise prevention and management is difficult as knowledge on specific sources is very limited in the literature. Furthermore, on field measurements are difficult to be performed given the complexity of the port area, where multiple types of sound emitters mix and confuse each other. Noise maps represent the first important step in order to align ports to the requirements set by the Environmental Noise Directive to the transportation infrastructures. Once computed, they are an excellent tool supporting port management towards the reduction of citizens\u2019 noise exposure while ensuring traffic growth. The present paper reports a guideline for the characterization of noise sources needed as inputs for the noise maps, as developed in the framework of the INTERREG Maritime programme Italy-France 2014\u20132020. On the basis of the current state of the art, a procedure has been elaborated for different categories of noise sources acting in port, ranging from stationary to moving ships, from mooring operations to loading/unloading operations, from industrial activities to road and railway traffic

    Chiral Fermions on the Lattice through Gauge Fixing -- Perturbation Theory

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    We study the gauge-fixing approach to the construction of lattice chiral gauge theories in one-loop weak-coupling perturbation theory. We show how infrared properties of the gauge degrees of freedom determine the nature of the continuous phase transition at which we take the continuum limit. The fermion self-energy and the vacuum polarization are calculated, and confirm that, in the abelian case, this approach can be used to put chiral gauge theories on the lattice in four dimensions. We comment on the generalization to the nonabelian case.Comment: 31 pages, 5 figures, two refs. adde

    Outcomes in Hybrid Breast Reconstruction: A Systematic Review

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    Background and Objectives: Lipofilling is a commonly performed procedure worldwide for breast augmentation and correction of breast contour deformities. In breast reconstruction, fat grafting has been used as a single reconstructive technique, as well as in combination with other procedures. The aim of the present study is to systematically review available studies in the literature describing the combination of implant-based breast reconstruction and fat grafting, focusing on safety, complications rate, surgical sessions needed to reach a satisfying reconstruction, and patient-reported outcomes. Materials and Methods: We adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) throughout the whole review protocol. A systematic review of the literature up to April 2022 was performed using Medline, Embase, and Cochrane Library databases. Only studies dealing with implant-based breast reconstruction combined with fat grafting were included. Results: We screened 292 articles by title and abstract. Only 48 articles were assessed for full-text eligibility, and among those, 12 studies were eventually selected. We included a total of 753 breast reconstructions in 585 patients undergoing mastectomy or demolitive breast surgeries other than mastectomy (quadrantectomy, segmentectomy, or lumpectomy) due to breast cancer or genetic predisposition to breast cancer. Overall, the number of complications was 60 (7.9%). The mean volume of fat grafting per breast per session ranged from 59 to 313 mL. The mean number of lipofilling sessions per breast ranged from 1.3 to 3.2. Conclusions: Hybrid breast reconstruction shows similar short-term complications to standard implant-based reconstruction but with the potential to significantly decrease the risk of long-term complications. Moreover, patient satisfaction was achieved with a reasonably low number of lipofilling sessions (1.7 on average)

    Performance evaluation of a commercial protective coating through field-exposure tests on three stone substrates

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    In the last decades, there have been several studies on Cultural Heritage regarding the performance of protective and consolidating coatings for the prevention of decay. A coating must have several characteristics such as efficiency, breathability, and must be durable and reversible. In this research work, the performance of a commercial protective product (Fosbuild FBLE 200) was evaluated. This coating is composed of a TiO2 nanopowder dispersed in an aqueous solution of an acrylic polymer. The product, which exhibits depolluting, antimicrobial, water-repellent and self-cleaning properties, has been applied on three different lithotypes: Carrara marble, Noto stone, and Comiso stone. Field-exposure tests were carried out in two different outdoor environments (Catania and Palermo) in order to assess its suitability. Promising results were obtained for the Carrara marble after one year of exposure; however, a decrease in effectiveness was observed at the end of the second year
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