29 research outputs found
A novel semi-fragile forensic watermarking scheme for remote sensing images
Peer-reviewedA semi-fragile watermarking scheme for multiple band images is presented. We propose to embed a mark into remote sensing images applying a tree structured vector quantization approach to the pixel signatures, instead of processing each band separately. The signature of themmultispectral or hyperspectral image is used to embed the mark in it order to detect any significant modification of the original image. The image is segmented into threedimensional blocks and a tree structured vector quantizer is built for each block. These trees are manipulated using an iterative algorithm until the resulting block satisfies a required criterion which establishes the embedded mark. The method is shown to be able to preserve the mark under lossy compression (above a given threshold) but, at the same time, it detects possibly forged blocks and their position in the whole image.Se presenta un esquema de marcas de agua semi-frágiles para múltiples imágenes de banda. Proponemos incorporar una marca en imágenes de detección remota, aplicando un enfoque de cuantización del vector de árbol estructurado con las definiciones de píxel, en lugar de procesar cada banda por separado. La firma de la imagen hiperespectral se utiliza para insertar la marca en el mismo orden para detectar cualquier modificación significativa de la imagen original. La imagen es segmentada en bloques tridimensionales y un cuantificador de vector de estructura de árbol se construye para cada bloque. Estos árboles son manipulados utilizando un algoritmo iteractivo hasta que el bloque resultante satisface un criterio necesario que establece la marca incrustada. El método se muestra para poder preservar la marca bajo compresión con pérdida (por encima de un umbral establecido) pero, al mismo tiempo, detecta posiblemente bloques forjados y su posición en la imagen entera.Es presenta un esquema de marques d'aigua semi-fràgils per a múltiples imatges de banda. Proposem incorporar una marca en imatges de detecció remota, aplicant un enfocament de quantització del vector d'arbre estructurat amb les definicions de píxel, en lloc de processar cada banda per separat. La signatura de la imatge hiperespectral s'utilitza per inserir la marca en el mateix ordre per detectar qualsevol modificació significativa de la imatge original. La imatge és segmentada en blocs tridimensionals i un quantificador de vector d'estructura d'arbre es construeix per a cada bloc. Aquests arbres són manipulats utilitzant un algoritme iteractiu fins que el bloc resultant satisfà un criteri necessari que estableix la marca incrustada. El mètode es mostra per poder preservar la marca sota compressió amb pèrdua (per sobre d'un llindar establert) però, al mateix temps, detecta possiblement blocs forjats i la seva posició en la imatge sencera
A global survey of health care workers' awareness of non-alcoholic fatty liver disease:The AwareNASH survey
Background: The estimated global prevalence and burden of non-alcoholic fatty liver disease (NAFLD) and its advanced stage, non-alcoholic steatohepatitis (NASH), is increasing. Yet, NAFLD remains largely underdiagnosed. In addition to hepatic morbidity and mortality, NAFLD is associated with increased cardiovascular complications, warranting a multidisciplinary approach. Despite its rapidly increasing prevalence, knowledge of NAFLD among healthcare workers is limited, especially with specialists outside the field of hepatology and gastroenterology. Objectives: To investigate knowledge, practice and opinions/attitudes of healthcare workers towards diagnosis and management of NAFLD/NASH. Methods: The survey was designed in collaboration with a multidisciplinary scientific committee established especially for this study. The survey was disseminated to healthcare workers from seven different disciplines through four collaborating societies, social media and at a cardiology-themed conference from February to June 2022. Median and interquartile range were mentioned for numeric responses and proportions for categorical responses or responses on a Likert scale. Likert scale responses were treated as ordinal data and analysed with the appropriate tests. Results: The full dataset included 613 respondents from 88 different countries (including 488 physicians). 64% of the surveyed physicians underestimated the prevalence of NAFLD. General practitioners and cardiologists underestimated the prevalence most often (74% and 77%, respectively). Compared to the other disciplines, cardiologists were least familiar with the symptoms and diagnostic criteria and felt least confident in diagnosing and managing NAFLD. Overall, 65% of physicians reported regularly using evidence-based guidelines for managing NAFLD, yet 72% reported challenges in providing lifestyle recommendations. A lack of awareness was the most common reported reason for the lack of screening for NAFLD (68% respectively). Conclusions: Despite the growing burden of NAFLD, there is a significant gap in awareness, knowledge, and management among physicians treating patients with cardiometabolic comorbidities, particularly cardiologists. Hepatologists and gastroenterologists could play a role in educating their fellow physicians.</p
Hot, rocky and warm, puffy super-Earths orbiting TOI-402 (HD 15337)
Context: The Transiting Exoplanet Survey Satellite (TESS) is revolutionising the search for planets orbiting bright and nearby stars. In sectors 3 and 4, TESS observed TOI-402 (TIC-120896927), a bright V = 9.1 K1 dwarf also known as HD 15337, and found two transiting signals with periods of 4.76 and 17.18 days and radii of 1.90 and 2.21 R⊕, respectively. This star was observed prior to the TESS detection as part of the radial-velocity (RV) search for planets using the HARPS spectrometer, and 85 precise RV measurements were obtained before the launch of TESS over a period of 14 yr.
Aims: In this paper, we analyse the HARPS RV measurements in hand to confirm the planetary nature of these two signals.
Methods: HD 15337 happens to present a stellar activity level similar to the Sun, with a magnetic cycle of similar amplitude and RV measurements that are affected by stellar activity. By modelling this stellar activity in the HARPS radial velocities using a linear dependence with the calcium activity index log(RHK′), we are able, with a periodogram approach, to confirm the periods and the planetary nature of TOI-402.01 and TOI-402.02. We then derive robust estimates from the HARPS RVs for the orbital parameters of these two planets by modelling stellar activity with a Gaussian process and using the marginalised posterior probability density functions obtained from our analysis of TESS photometry for the orbital period and time of transit.
Results: By modelling TESS photometry and the stellar host characteristics, we find that TOI-402.01 and TOI-402.02 have periods of 4.75642 ± 0.00021 and 17.1784 ± 0.0016 days and radii of 1.70 ± 0.06 and 2.52 ± 0.11 R⊕ (precision 3.6 and 4.2%), respectively. By analysing the HARPS RV measurements, we find that those planets are both super-Earths with masses of 7.20 ± 0.81 and 8.79 ± 1.68 M⊕ (precision 11.3 and 19.1%), and small eccentricities compatible with zero at 2σ.
Conclusions: Although having rather similar masses, the radii of these two planets are very different, putting them on different sides of the radius gap. By studying the temporal evolution under X-ray and UV (XUV) driven atmospheric escape of the TOI-402 planetary system, we confirm, under the given assumptions, that photo-evaporation is a plausible explanation for this radius difference. Those two planets, being in the same system and therefore being in the same irradiation environment are therefore extremely useful for comparative exoplanetology across the evaporation valley and thus bring constraints on the mechanisms responsible for the radius gap
Th17 Cells and IL-17 in Protective Immunity to Vaginal Candidiasis
Background: Th17 cells play a major role in coordinating the host defence in oropharyngeal candidiasis. In this study we investigated the involvement of the Th17 response in an animal model of vulvovaginal candidiasis (VVC). Methods: To monitor the course of infection we exploited a new in vivo imaging technique. Results: i) The progression of VVC leads to a strong influx of neutrophils in the vagina soon after the challenge which persisted despite the resolution of infection; ii) IL-17, produced by vaginal cells, particularly CD4 T cells, was detected in the vaginal wash during the infection, reaching a maximum 14 days after the challenge; iii) The amount and kinetics of IL-23 in vaginal fluids were comparable to those in vaginal cells; iv) The inhibition of Th17 differentiation led to significant inhibition of IL-17 production with consequent exacerbation of infection; v) An increased production of bdefensin 2 was manifested in cells of infected mice. This production was strongly reduced when Th17 differentiation was inhibited and was increased by rIL-17 treatment. Conclusions: These results imply that IL-17 and Th17, along with innate antimicrobial factors, have a role in the immune response to vaginal candidiasis
Rapidly Rising Transients in the Supernova - Superluminous Supernova Gap
The American Astronomical Society. All rights reserved..We present observations of four rapidly rising (trise ≈ 10 days) transients with peak luminosities between those of supernovae (SNe) and superluminous SNe (Mpeak ap; -20) - one discovered and followed by the Palomar Transient Factory (PTF) and three by the Supernova Legacy Survey. The light curves resemble those of SN 2011kl, recently shown to be associated with an ultra-long-duration gamma-ray burst (GRB), though no GRB was seen to accompany our SNe. The rapid rise to a luminous peak places these events in a unique part of SN phase space, challenging standard SN emission mechanisms. Spectra of the PTF event formally classify it as an SN II due to broad Hα emission, but an unusual absorption feature, which can be interpreted as either high velocity Hα (though deeper than in previously known cases) or Si ii (as seen in SNe Ia), is also observed. We find that existing models of white dwarf detonations, CSM interaction, shock breakout in a wind (or steeper CSM), and magnetar spin down cannot readily explain the observations. We consider the possibility that a "Type 1.5 SN" scenario could be the origin of our events. More detailed models for these kinds of transients and more constraining observations of future such events should help to better determine their nature. © 2016
Long-term risks after kidney donation : how do we inform potential donors? A survey from DESCARTES and EKITA transplantation working groups
Publisher Copyright: © The Author(s) 2021. Published by Oxford University Press on behalf of ERA-EDTA.BACKGROUND: Publications from the last decade have increased knowledge regarding long-term risks after kidney donation. We wanted to perform a survey to assess how transplant professionals in Europe inform potential kidney donors regarding long-term risks. The objectives of the survey were to determine how they inform donors and to what extent, and to evaluate the degree of variation. METHODS: All transplant professionals involved in the evaluation process were considered eligible, regardless of the type of profession. The survey was dispatched as a link to a web-based survey. The subjects included questions on demographics, the information policy of the respondent and the use of risk calculators, including the difference of relative and absolute risks and how the respondents themselves understood these risks. RESULTS: The main finding was a large variation in how often different long-term risks were discussed with the potential donors, i.e. from always to never. Eighty percent of respondents stated that they always discuss the risk of end-stage renal disease, while 56% of respondents stated that they always discuss the risk of preeclampsia. Twenty percent of respondents answered correctly regarding the relationship between absolute and relative risks for rare outcomes. CONCLUSIONS: The use of written information and checklists should be encouraged. This may improve standardization regarding the information provided to potential living kidney donors in Europe. There is a need for information and education among European transplant professionals regarding long-term risks after kidney donation and how to interpret and present these risks.Peer reviewe
Four molecular superconductors isolated as nanoparticles
(TMTSF)₂PF₆ and (TMTSF)₂ClO₄ Bechgaard salts, (BEDT-TTF)₂I₃, and TTF[Ni(dmit)₂]₂ [TMTSF = tetramethyltetraselenafulvalene; BEDT-TTF = bis(ethylenedithio)tetrathiafulvalene; TTF = tetrathiafulvalene; dmit = 1,3-dithiole-2-thione-4,5-dithiolate] are among the most popular molecular superconductors. They are grown as nanoparticles that exhibit properties in agreement with those of the bulk. The shape, size, and homogeneity of particles depend on the stabilizing agent and synthesis conditions. We report on the more recent conditions investigated (i) to produce nanoparticles of 35 nm for β-(BEDT-TTF)₂I₃, (ii) to reduce the particle size to 10-15 nm for TTF[Ni(dmit)₂]₂ and 3-5 nm for (TMTSF)₂ClO₄, and (iii) to improve the growth duration from days to one hour for (TMTSF)₂PF₆. Finally, we report evidence of superconductivity in (TMTSF)₂ClO₄ particles
Liver involvement in hereditary hemorrhagic telangiectasia: consensus recommendations
Study purpose: To formulate recommendations about clinical management of liver involvement in hereditary hemorrhagic telangiectasia (HHT), using a formal consensus development process. Process: A nominal group technique was used. A list of main clinical, diagnostic and therapeutic issues about liver involvement in HHT was generated by the organizing committee. Panel members then scored their agreement with each statement; the median score, and standard deviation for each statement were determined for each of the three successive panel rounds. These consensus statements formed the basis for recommendations graded with the strength and quality of supporting evidence. Recommendation Statements: Doppler US is sufficiently accurate and suitable for first-line imaging of the liver in the general HHT population. Liver biopsy in any patient with proven or suspected HHT should be avoided. Liver involvement in HHT is generally asymptomatic; in the minority of patients where it is symptomatic, morbidity and mortality can be substantial. The prevalence of focal nodular hyperplasia is much higher in patients with liver involvement by HHT than in the general population. Invasive therapies for liver involvement by HHT (namely liver transplantation) should be considered only in patients who have failed to respond to intensive medical therapy