5,553 research outputs found
Fisher Vectors Derived from Hybrid Gaussian-Laplacian Mixture Models for Image Annotation
In the traditional object recognition pipeline, descriptors are densely
sampled over an image, pooled into a high dimensional non-linear representation
and then passed to a classifier. In recent years, Fisher Vectors have proven
empirically to be the leading representation for a large variety of
applications. The Fisher Vector is typically taken as the gradients of the
log-likelihood of descriptors, with respect to the parameters of a Gaussian
Mixture Model (GMM). Motivated by the assumption that different distributions
should be applied for different datasets, we present two other Mixture Models
and derive their Expectation-Maximization and Fisher Vector expressions. The
first is a Laplacian Mixture Model (LMM), which is based on the Laplacian
distribution. The second Mixture Model presented is a Hybrid Gaussian-Laplacian
Mixture Model (HGLMM) which is based on a weighted geometric mean of the
Gaussian and Laplacian distribution. An interesting property of the
Expectation-Maximization algorithm for the latter is that in the maximization
step, each dimension in each component is chosen to be either a Gaussian or a
Laplacian. Finally, by using the new Fisher Vectors derived from HGLMMs, we
achieve state-of-the-art results for both the image annotation and the image
search by a sentence tasks.Comment: new version includes text synthesis by an RNN and experiments with
the COCO benchmar
Estimating single molecule conductance from spontaneous evolution of a molecular contact
We present an original method to estimate the conductivity of a single
molecule anchored to nanometric-sized metallic electrodes, using a Mechanically
Controlled Break Junction (MCBJ) operated at room temperature in liquid. We
record the conductance through the metal / molecules / metal nanocontact while
keeping the metallic electrodes at a fixed distance. Taking advantage of
thermal diffusion and electromigration, we let the contact naturally explore
the more stable configurations around a chosen conductance value. The
conductance of a single molecule is estimated from a statistical analysis of
raw conductance and conductance standard deviation data for molecular contacts
containing up to 14 molecules. The single molecule conductance values are
interpreted as time-averaged conductance of an ensemble of conformers at
thermal equilibrium.Comment: 25 pages, 6 figure
Colonial Organization of Mine Labour in Charcas 1 (Present-Day Bolivia) and Its Consequences 2 (Sixteenth to the Seventeenth Centuries)
This article analyses the changes in the organization of labour during the sixteenth and seventeenth centuries in colonial Charcas, present-day Bolivia, focusing on the role that different colonial authorities played in this process and its consequences. The Spanish took advantage of the pre-Hispanic organization of labour from the beginning of their conquest. However, in a colonial context, labour relations changed significantly, and the architect of those alterations was Viceroy Francisco de Toledo. We examine the transformations in mine labour carried out by the Spanish colonial polity; these had a significant effect not only on mining, but also on all labour relations in the southern colonial Andes.Fil: Gil Montero, Raquel. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Tandil. Instituto de GeografĂa, Historia y Ciencias Sociales. Universidad Nacional del Centro de la Provincia de Buenos Aires. Instituto de GeografĂa, Historia y Ciencias Sociales; ArgentinaFil: Zagalsky, Paula Cecilia. Universidad Nacional de Jujuy; Argentina. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentin
Prevalence and Risk Factors of Early-Stage Age-Related Macular Degeneration in Patients Examined at a Health Promotion Center in Korea
We evaluated the prevalence and risk factors for early age-related macular degeneration (AMD) in Koreans 50 yr of age or older who were examined at a single health promotion center. We retrospectively reviewed the records of 10,449 subjects who visited the center over a 6-month period. Fundus photography was performed on all subjects, and systematic risk factor analysis was conducted using a structured questionnaire. All patients (n = 322) were initially diagnosed with drusen or early AMD using fundoscopy; the control group (n = 10,127) were those yielding normal fundoscopy findings. The age- and gender-adjusted prevalence of early AMD was 3.08%. Advanced age, male gender, smoking status, hyperlipidemia, working outdoors, and residence in rural areas were all significantly associated with an increased risk for development of early AMD. Higher-level ingestion of fruit or herbal medication and an increased amount of exercise were associated with a lower risk of early AMD development. In our Korean cohort, consisting principally of relatively healthy, middle-class urban adults, the prevalence of early AMD was 3.08% that is similar to that reported in earlier epidemiological studies. Several modifiable risk factors such as smoking and hyperlipidemia are associated with the prevalence of early AMD in our cohort
Serum ferritin levels may have a pro-atherosclerotic role in coronary artery disease patients with sleep disordered breathing
Elevated ferritin levels may lead to oxidative stress, and are associated with coronary artery disease (CAD). Sleep disordered breathing (SDB) is frequently present in atherosclerosis patients, and causes endothelial dysfunction leading to atherosclerotic plaque progression. Hypoxic conditions, such as SDB, may upregulate ferritin. The aim of this study was to evaluate ferritin levels in CAD patients and to correlate ferritin levels with parameters related to CAD progression, including SDB. We studied 27 patients with CAD (defined as >30% coronary narrowing) and 29 controls. We found that ferritin was increased in CAD patients, and was positively correlated with the apnea–hypopnea index (AHI), age, Creactive protein (CRP), transferrin, hemoglobin, and testosterone levels, and was negatively correlated with O2 saturation. Nitrites and nitrates, an indirect measure of nitric oxide ( NO) concentration, were lower in CAD patients, and were negatively correlated with ferritin. The increase in ferritin may be related to oxidative stress, suggesting a possible pro-atherosclerotic role of increased ferritin in CAD patients with SDB
NMDB@Athens: Hybrid symposium on cosmic ray studies with neutron detectors
A brief overview is given regarding the presentations delivered at the NMDB@Athens meeting which was held, in a hybrid fashion, in September 2022. Participants joined both remotely but also physically at the National and Kapodistrian University of Athens, Greece. Unlike traditional cosmic ray meetings and conferences where the focus is mainly on the science related to neutron monitor measurements, the ›NMDB@Athens‹ meeting uniquely also addresses hardware issues related to these instruments and, importantly, also databases where different data products can be accessed by a growing and increasingly diverse user base. The present overview outlines and introduces the more detailed articles contained in the proceedings
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