National Research University – Higher School of Economics

About: National Research University – Higher School of Economics is a education organization based out in Moscow, Russia. It is known for research contribution in the topics: Population & Politics. The organization has 12873 authors who have published 23376 publications receiving 256396 citations.

Few-shot Generative Modelling with Generative Matching Networks

Abstract: Despite recent advances, the remaining bottlenecks in deep generative models are necessity of extensive training and difficulties with generalization from small number of training examples. We develop a new generative model called Generative Matching Network which is inspired by the recently proposed matching networks for one-shot learning in discriminative tasks. By conditioning on the additional input dataset, our model can instantly learn new concepts that were not available in the training data but conform to a similar generative process. The proposed framework does not explicitly restrict diversity of the conditioning data and also does not require an extensive inference procedure for training or adaptation. Our experiments on the Omniglot dataset demonstrate that Generative Matching Networks significantly improve predictive performance on the fly as more additional data is available and outperform existing state of the art conditional generative models.

Alterations of Functional Brain Connectivity After Long-Duration Spaceflight as Revealed by fMRI.

Abstract: The present study reports alterations of task-based functional brain connectivity in a group of 11 cosmonauts after a long-duration spaceflight, compared to a healthy control group not involved in the space program. To elicit the postural and locomotor sensorimotor mechanisms that are usually most significantly impaired when space travelers return to Earth, a plantar stimulation paradigm was used in a block design fMRI study. The motor control system activated by the plantar stimulation involved the pre-central and post-central gyri, SMA, SII/operculum, and, to a lesser degree, the insular cortex and cerebellum. While no post-flight alterations were observed in terms of activation, the network-based statistics approach revealed task-specific functional connectivity modifications within a broader set of regions involving the activation sites along with other parts of the sensorimotor neural network and the visual, proprioceptive, and vestibular systems. The most notable findings included a post-flight increase in the stimulation-specific connectivity of the right posterior supramarginal gyrus with the rest of the brain; a strengthening of connections between the left and right insulae; decreased connectivity of the vestibular nuclei, right inferior parietal cortex (BA40) and cerebellum with areas associated with motor, visual, vestibular, and proprioception functions; and decreased coupling of the cerebellum with the visual cortex and the right inferior parietal cortex. The severity of space motion sickness symptoms was found to correlate with a post- to pre-flight difference in connectivity between the right supramarginal gyrus and the left anterior insula. Due to the complex nature and rapid dynamics of adaptation to gravity alterations, the post-flight findings might be attributed to both the long-term microgravity exposure and to the readaptation to Earth's gravity that took place between the landing and post-flight MRI session. Nevertheless, the results have implications for the multisensory reweighting and gravitational motor system theories, generating hypotheses to be tested in future research.

Household Strategies for Coping with Poverty and Social Exclusion in Post-Crisis Russia

Abstract: For Russian households coping with economic hardship in the wake of the recent financial crisis, the choice of survival strategy has strongly depended on their human capital. The higher a household's level of human capital, the more likely it is to choose an active strategy. What strategies have Russian households used to cope with economic hardship in the wake of the recent financial crisis? Which coping strategies have been most effective in reducing poverty for different groups of households? And how have people been able to adapt to the dramatic drop in formal cash incomes? Lokshin and Yemtsov look at these questions using subjective evaluations of coping strategies used by household survey respondents to mitigate the effects of the Russian financial crisis on their welfare. The data come from two rounds (1996 and 1998) of the Russian Longitudinal Monitoring Survey. The results of their analysis show that a household's choice of survival strategy strongly depends on its human capital: The higher its level of human capital, the more likely it is to choose an active strategy (such as finding a supplementary job or increasing home production). Households with low levels of human capital, those headed by pensioners, and those whose members have low levels of education are more likely to suffer social exclusion. To prevent poverty from becoming entrenched, the trend toward marginalization and impoverishment of these groups of households needs to be monitored and targeted policy interventions need to be undertaken to reverse the trend. This paper - a joint product of Poverty and Human Resources, Development Research Group, and Poverty Reduction and Economic Management Sector Unit, Europe and Central Asia Region - is part of a larger effort in the Bank to understand household-level vulnerability to shocks and the ability of households to cope with crisis.

On an exponential representation of the gravitational S-matrix

Abstract: An exponential representation of the S-matrix provides a natural framework for understanding the semi-classical limit of scattering amplitudes. While sharing some similarities with the eikonal formalism it differs from it in details. Computationally, rules are simple because pieces that must be subtracted are given by combinations of unitarity cuts. Analyzing classical gravitational scattering to third Post-Minkowskian order in both maximal supergravity and Einstein gravity we find agreement with other approaches, including the contributions from radiation reaction terms. The kinematical relation for the two-body problem in isotropic coordinates follows immediately from this procedure, again with the inclusion of radiation reaction pieces up to third Post-Minkowskian order.