Feature Guided Masked Autoencoder for Self-supervised Learning in Remote Sensing

Self-supervised learning guided by masked image modelling, such as Masked AutoEncoder (MAE), has attracted wide attention for pretraining vision transformers in remote sensing. However, MAE tends to excessively focus on pixel details, thereby limiting the model's capacity for semantic understanding, in particular for noisy SAR images. In this paper, we explore spectral and spatial remote sensing image features as improved MAE-reconstruction targets. We first conduct a study on reconstructing various image features, all performing comparably well or better than raw pixels. Based on such observations, we propose Feature Guided Masked Autoencoder (FG-MAE): reconstructing a combination of Histograms of Oriented Graidents (HOG) and Normalized Difference Indices (NDI) for multispectral images, and reconstructing HOG for SAR images. Experimental results on three downstream tasks illustrate the effectiveness of FG-MAE with a particular boost for SAR imagery. Furthermore, we demonstrate the well-inherited scalability of FG-MAE and release a first series of pretrained vision transformers for medium resolution SAR and multispectral images.Comment: 13 pages, 8 figure

Red de colaboración en investigación de la educación estadistica

Nuestro grupo de trabajo busca iniciar una red de colaboración de grupos de investigación en educación de la probabilidad y estadística a nivel iberoamericano bajo la tutela de la RELME. El interés por la educación estadística no es nuevo, pues desde principios de la década de los 90’s el International Statistical Institute (ISI) fundó la International Association for Statistical Education (IASE). Desde entonces muchas acciones se han seguido a favor de la educación estadística, sin embargo, hacen falta iniciativas que ayuden a la interacción y colaboración de los grupos regionales de educación estadística iberoamericanos

Masked Image Modelling for Representation Learning in Earth Observation

Deep learning applied to Earth observation (EO) yields impressive results. However, a significant challenge in EO is the rapidly increasing data volume while limited annotation resources available. Self-supervised representation learning (SSL) employs large amounts of unlabeled data. Recently, Masked Image Modelling (MIM) demonstrated scalability in model and data size. MIM masks a defined ratio of the input image for training a model to predict the masked patches. The learnt encoder is transferred to downstream tasks. In this work, we explore a new approach of MIM for EO combining two state-of-the-art SSL methodologies. One employs the Masked Autoencoder (MAE), which asymmetrically masks and reconstructs the raw input with the aid of an encoder operating on the visible patches followed by a smaller decoder reconstructing. The second methodology utilizes the Masked Feature Prediction (MFP), where image feature descriptors get reconstructed. We test our approach on the SSL4E0-S12 dataset reconstructing Histogram Oriented Gradients (HOG). We evaluate the pre-trained model on a multi-class classification for EuroSAT. Experimental results indicate stable performance with more than 90% accuracy down to 10% of labeled data. An ablation study on data normalization reveals that linear classification downstream task accuracy benefits from normalization by up to 6%. In contrast, fine tuning accuracies are robust to data normalization

Estimation of Temperature Homogeneity in MEMS-Based Heating Nanochips via Quantitative HAADF-STEM Tomography

Sample holders for transmission electron microscopy (TEM) based on micro-electro-mechanical systems (MEMS) have recently become popular for investigating the behavior of nanomaterials under in situ or environmental conditions. The accuracy and reproducibility of these in situ holders are essential to ensure the reliability of experimental results. In addition, the uniformity of an applied temperature trigger across the MEMS chip is a crucial parameter. In this work, it is measured the temperature homogeneity of MEMS-based heating sample supports by locally analyzing the dynamics of heat-induced alloying of Au@Ag nanoparticles located in different regions of the support through quantitative fast high-angle annular dark-field scanning TEM tomography. These results demonstrate the superior temperature homogeneity of a microheater design based on a heating element shaped as a circular spiral with a width decreasing outwards compared to a double spiral-shaped designed microheater. The proposed approach to measure the local temperature homogeneity based on the thermal properties of bimetallic nanoparticles will support the future development of MEMS-based heating supports with improved thermal properties and in situ studies where high precision in the temperature at a certain position is required

An Extension of the Blinder-Oaxaca Decomposition to a Continuum of Comparison Groups

This paper proposes an extension of the Blinder-Oaxaca decomposition from two to a continuum of comparison groups. The proposed decomposition is then estimated for the case of racial wage differences in urban Peru, exploiting a novel data set that allows the capturing of mestizaje (racial mixtures)

Future theranostic strategies: emerging ovarian cancer biomarkers to bridge the gap between diagnosis and treatment

Ovarian cancers are a complex and heterogenic group of malignancies that are difficult to detect, diagnose and treat. Fortunately, considerable knowledge of ovarian cancer specific biomarkers has been generated, that is pertinent to the development of novel theranostic platforms by combining therapies and diagnostics. Genomic and proteomic data has been invaluable in providing critical biomolecular targets for ovarian cancer theranostic approaches. Exploitation of the wealth of biomarker research that has been conducted offers viable targets as beacons for ovarian cancer detection, diagnosis, and therapeutic targeting. These markers can be used in theranostics, a treatment strategy that combines therapy and diagnostics and is common in nuclear medicine, where radionuclides are used for both diagnosis and treatment. The development of theranostics has taken substantial focus in recent years in the battle against ovarian cancer. Yet to date only one theranostic technology has emerged in clinical practice. However, given the wealth of ovarian cancer biomarkers the field is poised to see the emergence of revolutionary disease treatment and monitoring outcomes through their incorporation into the development of theranostic strategies. The future of ovarian cancer treatment is set to enable precise diagnosis, targeted treatment, and vigilant monitoring. This review aims to assess the status of ovarian cancer diagnostic tools and biomarkers in practice, clinical development, or pre-clinical development, highlighting newly emerging theranostic applications

Subjective embodiment during the rubber hand illusion predicts severity of premonitory sensations and tics in Tourette Syndrome

In Tourette Syndrome, the expression of tics and commonly preceding premonitory sensations is associated with perturbed subjective feelings of self-control and agency. We compared responses to the Rubber Hand Illusion in 23 adults with TS and 22 controls. Both TS and control participants reported equivalent subjective embodiment of the artificial hand: feelings of ownership, location, and agency were greater during synchronous visuo-tactile stimulation, compared to asynchronous. However, individuals with TS did not manifest greater proprioceptive drift, an objective marker of embodiment observed in controls. An 'embodiment prediction error' index of the difference between subjective embodiment and objective proprioceptive drift correlated with severity of premonitory sensations. Feelings of ownership also correlated with premonitory sensation severity, and feelings of agency with tic severity. These findings suggest that subjective bodily ownership, as measured by the rubber hand illusion, contributes to susceptibility to the premonitory sensations that may be a precipitating factor in tics

Estimation of temperature homogeneity in MEMS-based heating nanochips via quantitative HAADF-STEM tomography

Sample holders for transmission electron microscopy (TEM) based on micro-electro-mechanical systems (MEMS) have recently become popular for investigating the behavior of nanomaterials under in situ or environmental conditions. The accuracy and reproducibility of these in situ holders are essential to ensure the reliability of experimental results. In addition, the uniformity of an applied temperature trigger across the MEMS chip is a crucial parameter. In this work, it is measured the temperature homogeneity of MEMS-based heating sample supports by locally analyzing the dynamics of heat-induced alloying of Au@Ag nanoparticles located in different regions of the support through quantitative fast high-angle annular dark-field scanning TEM tomography. These results demonstrate the superior temperature homogeneity of a microheater design based on a heating element shaped as a circular spiral with a width decreasing outwards compared to a double spiral-shaped designed microheater. The proposed approach to measure the local temperature homogeneity based on the thermal properties of bimetallic nanoparticles will support the future development of MEMS-based heating supports with improved thermal properties and in situ studies where high precision in the temperature at a certain position is required

Does having a twin-brother make for a bigger brain?

Objective: Brain volume of boys is larger than that of girls by ∼10%. Prenatal exposure to testosterone has been suggested in the masculinization of the brain. For example, in litter-bearing mammals intrauterine position increases prenatal testosterone exposure through adjacent male fetuses, resulting in masculinization of brain morphology. Design: The influence of intrauterine presence of a male co-twin on masculinization of human brain volume was studied in 9-year old twins. Methods: Magnetic resonance imaging brain scans, current testosterone, and estradiol levels were acquired from four groups of dizygotic (DZ) twins: boys from same-sex twin-pairs (SSM), boys from opposite-sex twin-pairs (OSM), girls from opposite-sex twin-pairs (OSF), and girls from same-sex twin-pairs (SSF; n=119 individuals). Data on total brain, cerebellum, gray and white matter volumes were examined. Results: Irrespective of their own sex, children with a male co-twin as compared to children with a female co-twin had larger total brain (+2.5%) and cerebellum (+5.5%) volumes. SSM, purportedly exposed to the highest prenatal testosterone levels, were found to have the largest volumes, followed by OSM, OSF and SSF children. Birth weight partly explained the effect on brain volumes. Current testosterone and estradiol levels did not account for the volumetric brain differences. However, the effects observed in children did not replicate in adult twins. Conclusions: Our study indicates that sharing the uterus with a DZ twin brother increases total brain volume in 9-year olds. The effect may be transient and limited to a critical period in childhood. © 2009 European Society of Endocrinology