Interpreting Vision and Language Generative Models with Semantic Visual Priors

When applied to Image-to-text models, interpretability methods often provide token-by-token explanations namely, they compute a visual explanation for each token of the generated sequence. Those explanations are expensive to compute and unable to comprehensively explain the model's output. Therefore, these models often require some sort of approximation that eventually leads to misleading explanations. We develop a framework based on SHAP, that allows for generating comprehensive, meaningful explanations leveraging the meaning representation of the output sequence as a whole. Moreover, by exploiting semantic priors in the visual backbone, we extract an arbitrary number of features that allows the efficient computation of Shapley values on large-scale models, generating at the same time highly meaningful visual explanations. We demonstrate that our method generates semantically more expressive explanations than traditional methods at a lower compute cost and that it can be generalized over other explainability methods

The Drosophila phosphatidylinositol transfer protein encoded by vibrator is essential to maintain cleavage-furrow ingression in cytokinesis

Cytokinesis requires the coordination of cytoskeletal and plasma membrane dynamics. A role for phosphatidylinositol lipids has been proposed for the successful completion of cytokinesis but this is still poorly characterised. Here, we show mutants of the gene vibrator, previously found to encode the Drosophila phosphatidylinositol transfer protein, produce multinucleate cells indicative of cytokinesis failure in male meiosis. Examination of fixed preparations of mutant spermatocytes showed contractile rings of anillin and actin that were of normal appearance at early stages but were larger and less well organised at later stages of cytokinesis than in wild-type cells. Time-lapse imaging revealed sequential defects in cytokinesis of vibrator spermatocytes. In cells that fail cytokinesis, central spindle formation occurred correctly, but furrow ingression was delayed and the central spindle did not become compressed to the extent seen in wild-type cells. Cells then stalled at this point before the apparent connection between the constricted cytoskeleton and the plasma membrane was lost; the furrow then underwent elastic regression. We discuss these defects in relation to multiple functions of phosphoinositol lipids in regulating actin dynamics and membrane synthesis

A morphological analyser for Maltese

This article describes the development of a free/open-source morphological description of Maltese, originally created as the analysis component in a rule-based machine translation system for Maltese to Arabic and later applied to other tasks. The lexicon formalism we use is lttoolbox, part of the Apertium machine translation platform. An evaluation of the analyser shows that the coverage is adequate, at 84.90%, while precision is 92.5% on a large automatically annotated test set and 96.2% on a smaller hand-validated set.peer-reviewe

Dark Energy Survey Year 3 results: Cosmology with moments of weak lensing mass maps

Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAMWe present a cosmological analysis using the second and third moments of the weak lensing mass (convergence) maps from the first three years of data (Y3) data of the Dark Energy Survey. The survey spans an effective area of 4139 square degrees and uses the images of over 100 million galaxies to reconstruct the convergence field. The second moment of the convergence as a function of smoothing scale contains information similar to standard shear 2-point statistics. The third moment, or the skewness, contains additional non-Gaussian information. The data is analyzed in the context of the ΛCDM model, varying five cosmological parameters and 19 nuisance parameters modeling astrophysical and measurement systematics. Our modeling of the observables is completely analytical, and has been tested with simulations in our previous methodology study. We obtain a 1.7% measurement of the amplitude of fluctuations parameter S8 ≡ σ8(ωm/0.3)0.5 = 0.784±0.013. The measurements are shown to be internally consistent across redshift bins, angular scales, and between second and third moments. In particular, the measured third moment is consistent with the expectation of gravitational clustering under the ΛCDM model. The addition of the third moment improves the constraints on S8 and ωm by ∼15% and ∼25% compared to an analysis that only uses second moments. We compare our results with Planck constraints from the cosmic microwave background, finding a 2.2-2.8σ tension in the full parameter space, depending on the combination of moments considered. The third moment, independently, is in 2.8σ tension with Planck, and thus provides a cross-check on the analyses of 2-point correlation

Optics and children

Light and Optics are subjects that “naturally” attracts the interest and sympathy of children even from very early ages. In this communication, we present a serie of experiments and support material designed in this hands-on perspective, to be used to introduce the study of light and optics to kindergarten and early basic school students. Our hands-on investigative approach leads the students, aged 4 to 10 years, to observe the experiment and discover themselves, in a critical and active way, different aspects of light and optics. Preparing funny eye catching situations and experiments predispose the children to work, effectively, enjoying themselves while building up their self-confidence.(undefined

Does interpregnancy BMI change affect the risk of complications in the second pregnancy? : Analysis of pooled data from Aberdeen, Finland and Malta

Open Access via Springer agreementPeer reviewedPublisher PD

Psychometric properties of the Belief about Medicines Questionnaire (BMQ) in the Maltese language

Background: Investigating beliefs about medicines has been of interest over the past years, with studies aiming to better understand theoretical reasons behind development of such beliefs. Objective: This study aimed to produce a culturally and contextually appropriate version of the Beliefs about Medicines Questionnaire (BMQ) in the Maltese language and to assess its psychometric properties. Methods: Medication beliefs were evaluated using the BMQ which is divided into two sections: BMQ-General (sub-scales: Overuse and Harm, 4 items per sub-scale) and BMQ-Specific (sub-scales: Necessity and Concerns, 5 items per sub-scale). Following translation/back translation, the Maltese version of the BMQ was applied to patients having asthma, diabetes, cardiovascular disease or depression who attended out-patients' clinics at the main state general hospital in Malta between June and September 2013. Cronbach's alpha coefficient, alpha, was used to determine internal consistency of the BMQ and Principal Component Analysis using Varimax rotation with Kaiser normalisation was carried out to analyse component loading of the items on the respective sub-scales. Results: The Maltese version of the BMQ showed acceptable internal consistency for the harm scale (alpha=0.56), the necessity scale (alpha=0.73) and the concerns scale (alpha=0.66), however the overuse scale gave poor internal consistency (alpha=0.48) due to the item on natural remedies which posed some difficulty in the Maltese sample. The final solution for Principal Component Analysis yielded a four-factor structure representing the 4 sub-scales of the BMQ, with results being comparable to previous studies out in different languages. Conclusion: The Maltese version of the BMQ was found to have acceptable psychometric properties for the beliefs about medicines in the Maltese population.peer-reviewe

Interpreting vision and language generative models with semantic visual priors

When applied to Image-to-text models, explainability methods have two challenges. First, they often provide token-by-token explanations namely, they compute a visual explanation for each token of the generated sequence. This makes explanations expensive to compute and unable to comprehensively explain the model's output. Second, for models with visual inputs, explainability methods such as SHAP typically consider superpixels as features. Since superpixels do not correspond to semantically meaningful regions of an image, this makes explanations harder to interpret. We develop a framework based on SHAP, that allows for generating comprehensive, meaningful explanations leveraging the meaning representation of the output sequence as a whole. Moreover, by exploiting semantic priors in the visual backbone, we extract an arbitrary number of features that allow the efficient computation of Shapley values on large-scale models, generating at the same time highly meaningful visual explanations. We demonstrate that our method generates semantically more expressive explanations than traditional methods at a lower compute cost and that it can be generalized to a large family of vision-language models