University of Amsterdam

About: University of Amsterdam is a education organization based out in Amsterdam, Noord-Holland, Netherlands. It is known for research contribution in the topics: Population & Randomized controlled trial. The organization has 59309 authors who have published 140894 publications receiving 5984137 citations. The organization is also known as: UvA & Universiteit van Amsterdam.

Analyzing Multi-Head Self-Attention: Specialized Heads Do the Heavy Lifting, the Rest Can Be Pruned

Abstract: Multi-head self-attention is a key component of the Transformer, a state-of-the-art architecture for neural machine translation. In this work we evaluate the contribution made by individual attention heads to the overall performance of the model and analyze the roles played by them in the encoder. We find that the most important and confident heads play consistent and often linguistically-interpretable roles. When pruning heads using a method based on stochastic gates and a differentiable relaxation of the L0 penalty, we observe that specialized heads are last to be pruned. Our novel pruning method removes the vast majority of heads without seriously affecting performance. For example, on the English-Russian WMT dataset, pruning 38 out of 48 encoder heads results in a drop of only 0.15 BLEU.

Microfluidics-based diagnostics of infectious diseases in the developing world

Abstract: Ready access to diagnostic tests that work well under remote field conditions is a major barrier to improving the health of people in the developing world. Here, Curtis Chin and his colleagues have developed a chip-based, microfluidic device and handheld reader for the simultaneous and rapid diagnosis of HIV and syphilis that uses only 1 μl of unprocessed whole blood and that was successfully field tested in Rwanda.

A universal radio-X-ray correlation in low/hard state black hole binaries

Abstract: Several independent lines of evidence now point to a connection between the physical processes that govern radio (i.e. jet) and X-ray emission from accreting X-ray binaries. We present a comprehensive study of (quasi-)simultaneous radio-X-ray observations of stellar black hole binaries during the spectrally hard X-ray state, finding evidence for a strong correlation between these two bands over more than three orders of magnitude in X-ray luminosity. The correlation extends from the quiescent regime up to close to the soft state transition, where radio emission starts to decline, sometimes below detectable levels, probably corresponding to the physical disappearance ofthe jet. The X-ray transient V404 Cygni is found to display the same functional relationship already reported for GX 339-4 between radio and X-ray flux, namely S r a d i o α S + 0 . 7 X. In fact, the data for all low/hard state black holes is consistent with a universal relation between the radio and X-ray luminosity of the form L r a d i o α L + 0 . 7 X. Under the hypothesis of common physics driving the disc-jet coupling in different sources, the observed spread to the best-fitting relation can be interpreted in terms of a distribution in Doppler factors and hence used to constrain the bulk Lorentz factors of both the radio- and X-ray-emitting regions. Monte Carlo simulations show that, assuming little or no X-ray beaming, the measured scatter in radio power is consistent with Lorentz factors? 2 for the outflows in the low/hard state, significantly less relativistic than the jets associated with X-ray transients. When combined radio and X-ray beaming is considered, the range of possible jet bulk velocities significantly broadens, allowing highly relativistic outflows, but therefore implying severe X-ray selection effects. If the radio luminosity scales as the total jet power raised to x > 0.7, then there exists an X-ray luminosity below which most of the accretion power will be channelled into the jet, rather than into X-rays. For x = 1.4, as in several optically thick jet models, the power output of 'quiescent' black holes may be jet-dominated below L X ≃ 4 × 10 - 5 L E d d .

Association between use of lung-protective ventilation with lower tidal volumes and clinical outcomes among patients without acute respiratory distress syndrome: a meta-analysis.

Abstract: Context Lung-protective mechanical ventilation with the use of lower tidal volumes has been found to improve outcomes of patients with acute respiratory distress syndrome (ARDS). It has been suggested that use of lower tidal volumes also benefits patients who do not have ARDS. Objective To determine whether use of lower tidal volumes is associated with improved outcomes of patients receiving ventilation who do not have ARDS.