Hyperparameter-free losses for model-based monocular reconstruction

This work proposes novel hyperparameter-free losses for single view 3D reconstruction with morphable models (3DMM). We dispense with the hyperparameters used in other works by exploiting geometry, so that the shape of the object and the camera pose are jointly optimized in a sole term expression. This simplification reduces the optimization time and its complexity. Moreover, we propose a novel implicit regularization technique based on random virtual projections that does not require additional 2D or 3D annotations. Our experiments suggest that minimizing a shape reprojection error together with the proposed implicit regularization is especially suitable for applications that require precise alignment between geometry and image spaces, such as augmented reality. We evaluate our losses on a large scale dataset with 3D ground truth and publish our implementations to facilitate reproducibility and public benchmarking in this field.Peer ReviewedPostprint (author's final draft

Visual-inertial self-calibration on informative motion segments

Environmental conditions and external effects, such as shocks, have a significant impact on the calibration parameters of visual-inertial sensor systems. Thus long-term operation of these systems cannot fully rely on factory calibration. Since the observability of certain parameters is highly dependent on the motion of the device, using short data segments at device initialization may yield poor results. When such systems are additionally subject to energy constraints, it is also infeasible to use full-batch approaches on a big dataset and careful selection of the data is of high importance. In this paper, we present a novel approach for resource efficient self-calibration of visual-inertial sensor systems. This is achieved by casting the calibration as a segment-based optimization problem that can be run on a small subset of informative segments. Consequently, the computational burden is limited as only a predefined number of segments is used. We also propose an efficient information-theoretic selection to identify such informative motion segments. In evaluations on a challenging dataset, we show our approach to significantly outperform state-of-the-art in terms of computational burden while maintaining a comparable accuracy

Advances in mapping ice-free surfaces within the Northern Antarctic peninsula region using polarimetric RADARSAT-2 data

Ice-free areas within the Northern Antarctic Peninsula region are of interest for studying changes occurring to surface covers, including those related to glacial coverage, raised beach deposits and periglacial processes and permafrost. The objective of this work is to map the main surface covers within ice-free areas of King George Island, the largest island of the South Shetlands archipelago, using fully polarimetric RADARSAT-2 SAR data. Surface covers such as rock outcrops and glacial till, stone fields, patterned ground, and sand and gravel deposits form the most representative classes and account for 84 km2 of the ice-free areas on the island. A distribution of complex geomorphological features and landforms was obtained, being some of them considered indicators of periglacial processes and presence of permafrost.Published versio

Cross-species analysis of gene expression in non-model mammals: reproducibility of hybridization on high density oligonucleotide microarrays

BACKGROUND: Gene expression profiles of non-model mammals may provide valuable data for biomedical and evolutionary studies. However, due to lack of sequence information of other species, DNA microarrays are currently restricted to humans and a few model species. This limitation may be overcome by using arrays developed for a given species to analyse gene expression in a related one, an approach known as "cross-species analysis". In spite of its potential usefulness, the accuracy and reproducibility of the gene expression measures obtained in this way are still open to doubt. The present study examines whether or not hybridization values from cross-species analyses are as reproducible as those from same-species analyses when using Affymetrix oligonucleotide microarrays. RESULTS: The reproducibility of the probe data obtained hybridizing deer, Old-World primates, and human RNA samples to Affymetrix human GeneChip(® )U133 Plus 2.0 was compared. The results show that cross-species hybridization affected neither the distribution of the hybridization reproducibility among different categories, nor the reproducibility values of the individual probes. Our analyses also show that a 0.5% of the probes analysed in the U133 plus 2.0 GeneChip are significantly associated to un-reproducible hybridizations. Such probes-called in the text un-reproducible probe sequences- do not increase in number in cross-species analyses. CONCLUSION: Our study demonstrates that cross-species analyses do not significantly affect hybridization reproducibility of GeneChips, at least within the range of the mammal species analysed here. The differences in reproducibility between same-species and cross-species analyses observed in previous studies were probably caused by the analytical methods used to calculate the gene expression measures. Together with previous observations on the accuracy of GeneChips for cross-species analysis, our analyses demonstrate that cross-species hybridizations may provide useful gene expression data. However, the reproducibility and accuracy of these measures largely depends on the use of appropriated algorithms to derive the gene expression data from the probe data. Also, the identification of probes associated to un-reproducible hybridizations-useless for gene expression analyses- in the studied GeneChip, stress the need of a re-evaluation of the probes' performance

Propositionalism without propositions, objectualism without objects

Propositionalism is the view that all intentional states are propositional states, which are states with a propositional content, while objectualism is the view that at least some intentional states are objectual states, which are states with objectual contents, such as objects, properties, and kinds. This paper argues that there are two distinct ways of understanding propositionalism and objectualism: (1) as views about the deep nature of the contents of intentional states, and (2) as views about the superficial character of the contents of intentional states. I argue that we should understand the views in the second way. I also argue that the propositionalism debate is fairly independent from debates over the deep nature of intentionality, and that this has implications for arguments for propositionalism and objectualism from claims about the nature of intentional content. I close with a short discussion of how related points apply to the debate over singular content

EL APRENDIZAJE DE LAS CIENCIAS SOCIALES Y LAS DIFERENCIAS BASADAS EN EL GÉNERO EN AICLE. UN ESTUDIO PRELIMINAR

This article shows the preliminary results of a longitudinal study that aims to (i) determine the impact of bilingual education on the acquisition of contents related to social sciences, and (ii) its effect on the reduction of gender-based achievement differences. To this end, the results of students in the 4th year of primary education (n = 119) of one bilingual and one non-bilingual school located in an urban area were compared. It was guaranteed that the groups were homogeneous in terms of socio-economic level, that they had received a similar teaching methodology and same amount of social science teaching hours (3 hours a week). The results showed (i) the students who received the subject of social sciences in English had acquired knowledge in a similar manner to those who had received it in their mother tongue and (ii) the bilingual education levelled the gender differences observed in the non-bilingual school in favour of males.En este artículo se muestran los resultados preliminares de un estudio longitudinal que se dirige a (i) determinar el impacto de la enseñanza bilingüe en la adquisición de los contenidos relativos a las ciencias sociales, y (ii) su efecto en la reducción de las diferencias de logro basadas en el género. Para ello se compararon los resultados de alumnos de 4º de educación primaria (n=119) de una escuela bilingüe y otra no bilingüe situadas en una zona urbana. Se garantizó que los grupos eran homogéneos en términos de nivel socio-económico, que habían recibido una metodología docente similar y el mismo número de horas de ciencias sociales (3 horas semanales). Los resultados mostraron (i) los alumnos que recibieron la asignatura de ciencias sociales en inglés habían adquirido conocimientos similares a los que la habían recibido en su lengua materna y (ii) la enseñanza bilingüe niveló las diferencias de género observadas en la escuela no bilingüe en favor de los varones.This article shows the preliminary results of a longitudinal study that aims to (i) determine the impact of bilingual education on the acquisition of contents related to social sciences, and (ii) its effect on the reduction of gender-based achievement differences. To this end, the results of students in the 4th year of primary education (n = 119) of one bilingual and one non-bilingual school located in an urban area were compared. It was guaranteed that the groups were homogeneous in terms of socio-economic level, that they had received a similar teaching methodology and same amount of social science teaching hours (3 hours a week). The results showed (i) the students who received the subject of social sciences in English had acquired knowledge in a similar manner to those who had received it in their mother tongue and (ii) the bilingual education levelled the gender differences observed in the non-bilingual school in favour of males.

Epigenetic biomarkers in the progression of Barrett’s Oesophagus to oesophageal adenocarcinoma

Introduction Barrett’s Oesophagus (BO) represents a benign condition with no life limiting consequences. 0.33% of BO patients progress to oesophageal adenocarcinoma (OADC) which is a potentially catastrophic illness with high associated morbidity and mortality. If patients at high risk of progression to cancer could be identified, they could potentially be treated at an earlier disease stage. Aims To assess existing epigenetic biomarkers predicting progression from BO to OADC and validate the novel methylation biomarker OR3A4. Explore the functional relevance of OR3A4 and assess the immunological landscape of BO which progresses to OADC. Methods Genome wide methylation analysis and validation pyrosequencing of OR3A4 in BO tissue samples was performed. An OR3A4 over-expressing vector was transfected into BO and OADC cell lines and cell functional assays, total RNA sequencing and real time PCR was performed. Multispectral immunohistochemistry was performed to investigate the immunological landscape of BO. Results OR3A4 is hypomethylated in patients that progress from BO to OADC and OR3A4 over-expression has a functional effect in BO in vitro models and may contribute to immunological changes in BO tissues. Conclusion Hypomethylation of OR3A4 may provide a mechanism to explain the progression of BO to OADC and predict progression of disease

Observability-aware Self-Calibration of Visual and Inertial Sensors for Ego-Motion Estimation

External effects such as shocks and temperature variations affect the calibration of visual-inertial sensor systems and thus they cannot fully rely on factory calibrations. Re-calibrations performed on short user-collected datasets might yield poor performance since the observability of certain parameters is highly dependent on the motion. Additionally, on resource-constrained systems (e.g mobile phones), full-batch approaches over longer sessions quickly become prohibitively expensive. In this paper, we approach the self-calibration problem by introducing information theoretic metrics to assess the information content of trajectory segments, thus allowing to select the most informative parts from a dataset for calibration purposes. With this approach, we are able to build compact calibration datasets either: (a) by selecting segments from a long session with limited exciting motion or (b) from multiple short sessions where a single sessions does not necessarily excite all modes sufficiently. Real-world experiments in four different environments show that the proposed method achieves comparable performance to a batch calibration approach, yet, at a constant computational complexity which is independent of the duration of the session

Langerin-Heparin Interaction: Two Binding Sites for Small and Large Ligands as revealed by a combination of NMR Spectroscopy and Cross-Linking Mapping Experiments

Langerin is a C-type lectin present on Langerhans cells that mediates capture of pathogens in a carbohydrate-dependent manner, leading to subsequent internalization and elimination in the cellular organelles called Birbeck granules. This mechanism mediated by langerin was shown to constitute a natural barrier for HIV-1 particle transmission. Besides interacting specifically with high mannose and fucosylated neutral carbohydrate structures, langerin has the ability to bind sulfated carbohydrate ligands as 6-sulfated galactosides in the Ca2+ dependent binding site. Very recently langerin was demonstrated to interact with sulfated glycosaminoglycans (GAGs), in a Ca2+ independent way, resulting in the proposal of a new binding site for GAGs. Based on those results, we have conducted a structural study of the interactions of small heparin (HEP) like oligosaccharides with langerin in solution. Heparin-bead cross-linking experiments, an approach specifically designed to identify HEP/HS binding sites in proteins were first carried out and experimentally validated the previously proposed model for the interaction of Lg ECD with 6 kDa HEP. High-resolution NMR studies of a set of 8 synthetic HEP-like trisaccharides harboring different sulfation patterns demonstrated that all of them bound to langerin in a Ca2+ dependent way. The binding epitopes were determined by STD NMR and the bound conformations by transferred NOESY experiments. These experimental data were combined with docking and molecular dynamics and resulted in the proposal of a binding mode characterized by the coordination of calcium by the two equatorial hydroxyl groups OH3 and OH4 at the non-reducing end. The binding also includes the carboxylate group at the adjacent iduronate residue. Such epitope is shared by all the 8 ligands, explaining the absence of any impact on binding from their differences in substitution pattern. Finally, in contrast to the small trisaccharides, we demonstrated that a longer HEP-like hexasaccharide, bearing an additional O-sulfate group at the non-reducing end, which precludes binding to the Ca2+ site, interacts with langerin in the previously identified Ca2+ independent binding site