636 research outputs found

    CAPTCHaStar! A novel CAPTCHA based on interactive shape discovery

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    Over the last years, most websites on which users can register (e.g., email providers and social networks) adopted CAPTCHAs (Completely Automated Public Turing test to tell Computers and Humans Apart) as a countermeasure against automated attacks. The battle of wits between designers and attackers of CAPTCHAs led to current ones being annoying and hard to solve for users, while still being vulnerable to automated attacks. In this paper, we propose CAPTCHaStar, a new image-based CAPTCHA that relies on user interaction. This novel CAPTCHA leverages the innate human ability to recognize shapes in a confused environment. We assess the effectiveness of our proposal for the two key aspects for CAPTCHAs, i.e., usability, and resiliency to automated attacks. In particular, we evaluated the usability, carrying out a thorough user study, and we tested the resiliency of our proposal against several types of automated attacks: traditional ones; designed ad-hoc for our proposal; and based on machine learning. Compared to the state of the art, our proposal is more user friendly (e.g., only some 35% of the users prefer current solutions, such as text-based CAPTCHAs) and more resilient to automated attacks.Comment: 15 page

    Influence of Biochar on the Properties of Antibacterial PBAT/Carvacrol Films

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    In recent years, there has been an increasing interest in antibacterial biopolymeric films. Among the different approaches for tuning the release kinetic of antibacterial compounds, the use of natural fillers allows for this purpose while optimizing the processability and the mechanical properties of the products. In this work, the effect of three different concentrations of biochar (BC) was investigated on the morphological, rheological, mechanical, and thermal properties of Polybutylene adipate terephthalate/Carvacrol/BC (PBAT/CV/BC) ternary biocomposites. The films were fabricated by means of melt mixing and compression molding and compared to PBAT/BC samples. The carvacrol kinetic release was evaluated as a function of the BC concentration in the ternary system. Results highlighted that BC allows tuning the properties of PBAT and of PBAT/CV samples and modifying the release kinetic of CV. Finally, the antimicrobial analysis revealed that PBAT/CV films exhibited excellent antimicrobial properties against Escherichia coli, Listeria monocytogenes, Salmonella Enteritidis, and Staphylococcus aureus

    Evidence of destabilization of the human thymidylate synthase (hTS) dimeric structure induced by the interface mutation Q62R

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    In human cells, thymidylate synthase (TS) provides the only source of 2\u2019-deoxythymidyne-5\u2019-monophosphate (dTMP), which is required for DNA biosynthesis. Because of its pivotal role, human TS (hTS) represents a validated target for anticancer chemotherapy. Nonetheless, the efficacy of drugs blocking the hTS active site has limitations due to the onset of resistance in cancer cells, requiring the identification of new strategies to effectively inhibit this enzyme. Human TS works as an obligate homodimer, making the inter-subunit interface an attractive targetable area. Here, we report the design and investigation of a new hTS variant, in which Gln62, located at the dimer interface, has been replaced by arginine in order to destabilize the enzyme quaternary assembly. The hTS Q62R variant has been characterized though kinetic assay, thermal denaturation analysis and X-ray crystallography. Our results provide evidence that hTS Q62R has a reduced melting temperature. The effective destabilization of the TS quaternary structure is also confirmed by structural analysis, showing that the introduced mutation induces a slight aperture of the hTS dimer. The generation of hTS variants having a more accessible interface area can facilitate the screening of interface-targeting molecules, providing key information for the rational design of innovative hTS interface inhibitors

    affron®, a standardised extract from saffron (Crocus sativus L.) for the treatment of youth anxiety and depressive symptoms: A randomised, double-blind, placebo-controlled study

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    Background: Saffron has antidepressant and anxiolytic effects in adults with mild-to-moderate depression. However, this is the first study examining its mood-related effects in teenagers. Methods: In this 8-week, randomised, double-blind, placebo-controlled study, youth aged 12–16 years, with mild-to-moderate anxiety or depressive symptoms were given tablets containing placebo or a saffron extract (affron®, 14 mg b.i.d). The youth and parent versions of the Revised Child Anxiety and Depression Scale (RCADS) were used as outcome measures. Results: 80 participants were enrolled and 68 completed the study. Based on youth self-reports, affron®was associated with greater improvements in overall internalising symptoms (p = 0.049), separation anxiety (p = 0.003), social phobia (p = 0.023), and depression (p = 0.016). Total internalising scores decreased by an average of 33% compared to 17% in the placebo group (p = 0.029). However, parental reports of improvements were inconsistent as mean improvements in RCADS scores were greater in the saffron group (40% vs 26%) (p = 0.026), although no other significant differences were identified. affron®was well-tolerated and there was a trend of reduced headaches in participants on the active treatment. Limitations: The use of a self-report instrument, limited study duration, single treatment dose, and non-clinical sample used in this study limit the generalisability of study findings. Conclusion: The administration of a standardised saffron extract (affron®) for 8 weeks improved anxiety and depressive symptoms in youth with mild-to-moderate symptoms, at least from the perspective of the adolescent. However, these beneficial effects were inconsistently corroborated by parents.This study was funded by Pharmactive Biotech Products SL. Pharmactive Biotech Products was not involved in the design of the research, analysis of data, or in the writing of the report. The authors gratefully acknowledge Pharmactive Biotech Products SL Company for funding the project and supplying affron® and LIPA Pharmaceuticals for the preparation of the tablet

    Knowing the social reality of mothers of premature newborns in Hospital Lagomaggiore

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    Unos 343 bebés prematuros nacieron en 2016 en Mendoza. Se producen aproximadamente 35.000 nacimientos anuales, de los cuales, el 10 % corresponde a bebés menores de 37 semanas y el 1% menores de 32 semanas. Por lo tanto queremos conocer cuál es la realidad social y nutricional de las madres de niños prematuros que dieron a luz en el Hospital Lagomaggiore en un período de tres meses y analizar cuál es el tratamiento periodístico de los diarios papel de Mendoza con su reproducción de notas periodísticas online relacionadas con el tema. La prematurez puede estar asociada a diferentes factores: madres adolescentes, intervalo corto entre gestaciones, embarazo múltiple, las infecciones y el estrés, pero el objetivo es focalizarse en las causas sociales (qué función cumplen los medios de comunicación para informar y educar, y si el Ministerio de Salud utiliza a los medios de comunicación como nexo para llegar a esta población), y el aspecto nutricional de las madres. Según datos de UNICEF, la primera causa de la mortalidad infantil en menores de un año en Argentina es la prematurez. Según una encuesta realizada por la ONG, mueren más de 4.500 prematuros cada año en la Argentina y Mendoza no escapa a esta realidad. La sobrevida de quienes pesaron menos de 1.500 g al nacer mejoró en la última década, pero estamos lejos de los estándares internacionales

    Use of biochar as filler for biocomposite blown films: Structure-processing-properties relationships

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    In this work, biocomposite blown films based on poly(butylene adipate-co-terephthalate) (PBAT) as biopolymeric matrix and biochar (BC) as filler were successfully fabricated. The materials were subjected to a film-blowing process after being compounded in a twin-screw extruder. The preliminary investigations conducted on melt-mixed PBAT/BC composites allowed PBAT/BC 5% and PBAT/BC 10% to be identified as the most appropriate formulations to be processed via film blowing. The blown films exhibited mechanical performances adequate for possible application as film for packaging, agricultural, and compost bags. The addition of BC led to an improvement of the elastic modulus, still maintaining high values of deformation. Water contact angle measurements revealed an increase in the hydrophobic behavior of the biocomposite films compared to PBAT. Additionally, accelerated degradative tests monitored by tensile tests and spectroscopic analysis revealed that the filler induced a photo-oxidative resistance on PBAT by delaying the degradation phenomena

    Productive performance and histological features of intestinal mucosa of broiler chickens fed different dietary protein levels

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    ABSTRACT To evaluate the effect of decreasing dietary protein on growth performance, carcass traits, and intestinal mucosal morphometry, 180 female Hubbard strain broiler chickens were divided into 3 groups and fed 3 isoenergetic diets ad libitum from 14 d of age until slaughter age (49 d). The treatments varied according to 3 protein levels: high-protein diet (HiP, 22.5% CP, DM basis), medium-protein diet (MedP, 20.5% CP), and low-protein diet (LowP, 18.5%). Diets were obtained by replacing wheat middlings with soybean meal and were formulated to meet or exceed broiler amino acid requirements of the NRC. Morphometric indices of duodenum, jejunum, and ileum were measured at the end of the feeding period and included villus height, crypt depth, villus-to-crypt ratio, and apparent villus surface area. The dietary protein level had a significant effect on final BW of birds, whereas ADG, ADFI, and feed efficiency remained unaffected by dietary treatment. The muscle (breast and drumstick) yields were significantly higher in birds fed the HiP diet compared with those of the MedP and LowP diets. Meat quality traits were not affected by the protein level. The villus surface area of all intestinal segments did not change among groups. Instead, reducing the dietary protein level to 20.5% resulted in a higher villus height and villus height to crypt depth ratio in the duodenum and ileum. On the basis of our findings, even if the high-protein diet promoted meat yield, a medium-protein diet could positively support broiler growth performance, as confirmed by favorable morphometric features of the intestine

    Examining the Ability of an FSO Receiver to Simultaneously Communicate with Multiple Transmitters

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    FSO (Free-Space Optical)-based communication systems experience difficulty with receiving and separating signals arising from multiple transmitters, a capability that would facilitate implementation of MIMO (Multiple-In, Multiple-Out) systems. Current implementations require multiple, distinct optical antennas, each tracking a single user, which proves bulky and costly, especially if the transmitters are moving and must be tracked. A fiber-bundle receiver has the potential to use multiple pathways, corresponding to the individual fibers within the receiver, to capture different combinations of the incoming optical signals. If the bundle provides linear combining of the optical signals from both the individual fibers in the bundle and amongst the incoming optical signals, signal processing could extract the individual signals from the combinations. In this paper, we experimentally investigate whether the fiber-bundle receiver possesses sufficient linearity of operation to allow the separation of two signals by simple processing algorithms, for both turbulent and non-turbulent conditions. Data from two distinct sources enters a single-bundle, single field of view receiver, and a basis signal from one transmitter provides the reference for performing simple subtraction-based extraction of the unknown signal from the other transmitter. The experimental results show that the receiver does operate linearly, and that the linear operation remains sufficiently intact in the presence of turbulence to extract a recognizable copy of one signal from the other. The ability of the fiber bundle receiver to mitigate turbulence effects appears to assist in maintaining this sufficient level of linearity
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