3,376 research outputs found
Diffractive di-jet production at the LHC with a Reggeon contribution
We study hard diffractive scattering in hadron–hadron collisions including, on top of the standard Pomeron-initiated processes, contributions due to the exchange of Reggeons. Using a simple model to describe the parton content of the Reggeon, we compute di-jet production in single diffractive and central diffractive events. We show that Reggeon contributions can be sizable at the LHC, and even sometimes dominant, and we identify kinematic windows in which they could be experimentally studied. We argue that suitable measurements must be performed in order to properly constrain the model, and be able to correctly account for Reggeon exchanges in the analysis of the many hard diffractive observables to be measured at the LHC.SCOAP
Assessment of speckle denoising filters for digital holography using subjective and objective evaluation models
Digital holography is an emerging imaging technique for displaying and sensing three dimensional objects. The perceived image quality of a hologram is frequently corrupted by speckle noise due to coherent illumination. Although several speckle noise reduction methods have been developed so far, there are scarce quality assessment studies to address their performance and they typically focus solely on objective metrics. However, these metrics do not reflect the visual quality perceived by a human observer.
In this work, the performance of four speckle reduction algorithms, namely the nonlocal means, the Lee, the Frost and the block matching 3D filters, with varying parameterizations, were subjectively evaluated. The results were ranked with respect to the perceived image quality to obtain the mean opinion scores using pairwise comparison. The correlation between the subjective results and twenty different no-reference objective quality metrics was evaluated.
The experiment indicates that block matching 3D and Lee are the preferred filters, depending on hologram characteristics. The best performing objective metrics were identified for each filter.info:eu-repo/semantics/publishedVersio
Early Cardiac Mitochondrial Molecular and Functional Responses to Acute Anthracycline Treatment in Wistar Rats
Doxorubicin (DOX) is an anticancer drug widely used to treat human and nonhuman tumors but the late and persistent cardio-toxicity reduces the therapeutic utility of the drug. The full mechanism(s) of DOX-induced acute, subchronic and delayed toxicity, which has a preponderant mitochondrial component, remains unclear; therefore, it is clinically relevant to identify early markers to identify patients who are predisposed to DOX-related cardiovascular toxicity. To address this, Wistar rats (16 weeks old) were treated with a single DOX dose (20 mg/kg, i.p.); then, mRNA, protein levels and functional analysis of mitochondrial endpoints were assessed 24 h later in the heart, liver, and kidney. Using an exploratory data analysis, we observed cardiac-specific alterations after DOX treatment for mitochondrial complexes III, IV, and preferentially for complex I. Conversely, the same analysis revealed complex II alterations are associated with DOX response in the liver and kidney. Interestingly, H2O2 production by the mitochondrial respiratory chain as well as loss of calcium-loading capacity, markers of subchronic toxicity, were not reliable indicators of acute DOX cardiotoxicity in this animal model. By using sequential principal component analysis and feature correlation analysis, we demonstrated for the first time alterations in sets of transcripts and proteins, but not functional measurements, that might serve as potential early acute markers of cardiac-specific mitochondrial toxicity, contributing to explain the trajectory of DOX cardiac toxicity and to develop novel interventions to minimize DOX cardiac liabilities
Audiovisual Quality of Live Music Streaming over Mobile Networks using MPEG-DASH
The MPEG-DASH protocol has been rapidly adopted by most major network content providers and enables clients to make informed decisions in the context of HTTP streaming, based on network and device conditions using the available media representations. A review of the literature on adaptive streaming over mobile shows that most emphasis has been on adapting the video quality whereas this work examines the trade-off between video and audio quality. In particular, subjective tests were undertaken for live music streaming over emulated mobile networks with MPEG-DASH. A group of audio/video sequences was designed to emulate varying bandwidth arising from network congestion, with varying trade-off between audio and video bit rates. Absolute Category Rating was used to evaluate the relative impact of both audio and video quality in the overall Quality of Experience (QoE). One key finding from the statistical analysis of Mean Opinion Scores (MOS) results using Analysis of Variance indicates that providing reduced audio quality has a much lower impact on QoE than reducing video quality at similar total bandwidth situations. This paper also describes an objective model for audiovisual quality estimation that combines the outcomes from audio and video metrics into a joint parametric model. The correlation between predicted and subjective MOS was computed using several outcomes (Pearson and Spearman correlation coefficients, Root Mean Square Error (RMSE) and epsilon-insensitive RMSE). The obtained results indicate that the proposed approach is a viable solution for objective audiovisual quality assessment in the context of live music streaming over mobile network.info:eu-repo/semantics/acceptedVersio
Índice de ajuste de comorbidade para a 10a revisão da classificação internacional de doenças
OBJECTIVE: To develop a Charlson-like comorbidity index based on clinical conditions and weights of the original Charlson comorbidity index. METHODS: Clinical conditions and weights were adapted from the International Classification of Diseases, 10th revision and applied to a single hospital admission diagnosis. The study included 3,733 patients over 18 years of age who were admitted to a public general hospital in the city of Rio de Janeiro, southeast Brazil, between Jan 2001 and Jan 2003. The index distribution was analyzed by gender, type of admission, blood transfusion, intensive care unit admission, age and length of hospital stay. Two logistic regression models were developed to predict in-hospital mortality including: a) the aforementioned variables and the risk-adjustment index (full model); and b) the risk-adjustment index and patient's age (reduced model). RESULTS: Of all patients analyzed, 22.3% had risk scores >;1, and their mortality rate was 4.5% (66.0% of them had scores >;1). Except for gender and type of admission, all variables were retained in the logistic regression. The models including the developed risk index had an area under the receiver operating characteristic curve of 0.86 (full model), and 0.76 (reduced model). Each unit increase in the risk score was associated with nearly 50% increase in the odds of in-hospital death. CONCLUSIONS: The risk index developed was able to effectively discriminate the odds of in-hospital death which can be useful when limited information is available from hospital databases.OBJETIVO: Desarrollar un índice de co-morbilidad a partir de las condiciones clínicas y de los pesos de índice original de co-morbilidad de Charlson. MÉTODOS: Las condiciones clínicas y pesos del índice de Charlson fueron adaptados según la Clasificación Internacional de Enfermedades - 10a Revisión, y aplicados al diagnóstico principal de internación hospitalaria. Fueron estudiados 3.733 pacientes arriba de 18 años hospitalizados en el hospital general público del municipio de Rio de Janeiro (sudeste de Brasil), de 2001-2003. La distribución del índice fue de acuerdo con el género, tipo de admisión, presencia de transfusión de sangre, admisión a la unidad de terapia intensiva, edad y tiempo de internación. Dos modelos de regresión logística fueron desarrollados con el objetivo de prevenir la mortalidad hospitalaria: a) con las variables arriba y el índice de co-morbilidad (modelo completo); y b) conteniendo solo el índice y la edad de los pacientes (modelo reducido). RESULTADOS: Dentro del total de pacientes analizados, 22,3% tuvieron puntajes >;1 para el índice y su taza de mortalidad fue 4,5% (66,0% de los cuales con puntajes >;1). A excepción del género y del tipo de admisión todas las variables fueron retenidas en la regresión. Los modelos tuvieron una área bajo la curva característica ROC igual a 0,86 (modelo completo) y 0,76 (modelo reducido). Cada aumento de una unidad en los puntajes del índice fue asociado con un aumento de casi 50% en la probabilidad de mortalidad hospitalaria. CONCLUSIONES: El índice desarrollado puede discriminar probabilidades de mortalidad con una eficacia aceptable, el que puede ser útil al ser usado con bancos de datos hospitalarios con información limitada.OBJETIVO: Desenvolver um índice de co-morbidade a partir das condições clínicas e dos pesos do índice de co-morbidade de Charlson. MÉTODOS: As condições clínicas e pesos do índice de Charlson foram adaptados segundo a Classificação Internacional de Doenças 10a Revisão, e aplicados ao diagnóstico principal de internação hospitalar. Foram estudados 3.733 pacientes acima de 18 anos hospitalizados em hospital geral público do município do Rio de Janeiro, RJ, 2001-2003. A distribuição do índice foi de acordo com o gênero, tipo da admissão, presença de transfusão de sangue, admissão à unidade de terapia intensiva, idade e tempo de internação. Dois modelos de regressão logística foram desenvolvidos com o objetivo de prever a mortalidade hospitalar desses pacientes: a) com as variáveis acima e o índice de co-morbidade (modelo completo); e b) contendo apenas o índice e a idade dos pacientes (modelo reduzido). RESULTADOS: Dentre o total de pacientes analisados, 22,3% possuíam escores >;1 para o índice e sua taxa de mortalidade foi 4,5% (66,0% dos quais com escores >;1). Exceto gênero e do tipo de admissão, todas as variáveis foram retidas na regressão. Os modelos tiveram uma área sob a curva característica ROC igual a 0,86 (modelo completo) e 0,76 (modelo reduzido). Cada aumento de uma unidade nos escores do índice foi associado com um aumento de quase 50% na probabilidade de mortalidade hospitalar. CONCLUSÕES: O índice desenvolvido pôde discriminar probabilidades de mortalidade com uma eficácia aceitável, o que pode ser útil ao lidar-se com bancos de dados hospitalares com informação limitada
Amortized Bootstrapping Revisited: Simpler, Asymptotically-faster, Implemented
Micciancio and Sorrel (ICALP 2018) proposed a bootstrapping algorithm that can refresh many messages at once with sublinearly many homomorphic operations per message. However, despite the attractive asymptotic cost, it is unclear if their algorithm could ever be practical, which reduces the impact of their results. In this work, we follow their general framework, but propose an amortized bootstrapping that is conceptually simpler and asymptotically cheaper. We reduce the number of homomorphic operations per refreshed message from to , and the noise overhead from to . We also make it more general, by handling non-binary messages and applying programmable bootstrapping.
To obtain a concrete instantiation of our bootstrapping algorithm, we propose a double-CRT (aka RNS) version of the GSW scheme, including a new operation, called shrinking, used to speed-up homomorphic operations by reducing the dimension and ciphertext modulus of the ciphertexts. We also provide a C++ implementation of our algorithm, thus showing for the first time the practicability of the amortized bootstrapping. Moreover, it is competitive with existing bootstrapping algorithms, being even around 3.4 times faster than an equivalent non-amortized version of our bootstrapping
Holographic representation: Hologram plane vs. object plane
Digital holography allows the recording, storage and subsequent reconstruction of both amplitude and phase of the light field scattered by an object. This is accomplished by recording interference patterns that preserve the properties of the original object field essential for 3D visualization, the so-called holograms.
Digital holography refers to the acquisition of holograms with a digital sensor, typically a CCD or a CMOS camera, and to the reconstruction of the 3D object field using numerical methods.
In the current work, the different representations of digital holographic information in the hologram and in the object planes are studied. The coding performance of the different complex field representations, notably Amplitude-Phase and Real-Imaginary, in both the hologram plane and the object plane, is assessed using both computer generated and experimental holograms. The HEVC intra main coding profile is used for the compression of the different representations in both planes, either for experimental holograms or computer generated holograms.
The HEVC intra compression in the object plane outperforms encoding in the hologram plane. Furthermore, encoding computer generated holograms in the object plane has a larger benefit than the same encoding over the experimental holograms. This difference was expected, since experimental holograms are affected by a larger negative influence of speckle noise, resulting in a loss of compression efficiency.
This work emphasizes the possibility of holographic coding on the object plane, instead of the common encoding in the hologram plane approach. Moreover, this possibility allows direct visualization of the Object Plane Amplitude in a regular 2D display without any transformation methods. The complementary phase information can easily be used to render 3D features such as depth map, multi-view or even holographic interference patterns for further 3D visualization depending on the display technology.info:eu-repo/semantics/publishedVersio
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