Data-Driven Sparse Structure Selection for Deep Neural Networks

Deep convolutional neural networks have liberated its extraordinary power on various tasks. However, it is still very challenging to deploy state-of-the-art models into real-world applications due to their high computational complexity. How can we design a compact and effective network without massive experiments and expert knowledge? In this paper, we propose a simple and effective framework to learn and prune deep models in an end-to-end manner. In our framework, a new type of parameter -- scaling factor is first introduced to scale the outputs of specific structures, such as neurons, groups or residual blocks. Then we add sparsity regularizations on these factors, and solve this optimization problem by a modified stochastic Accelerated Proximal Gradient (APG) method. By forcing some of the factors to zero, we can safely remove the corresponding structures, thus prune the unimportant parts of a CNN. Comparing with other structure selection methods that may need thousands of trials or iterative fine-tuning, our method is trained fully end-to-end in one training pass without bells and whistles. We evaluate our method, Sparse Structure Selection with several state-of-the-art CNNs, and demonstrate very promising results with adaptive depth and width selection.Comment: ECCV Camera ready versio

Effective temperature for black holes

The physical interpretation of black hole's quasinormal modes is fundamental for realizing unitary quantum gravity theory as black holes are considered theoretical laboratories for testing models of such an ultimate theory and their quasinormal modes are natural candidates for an interpretation in terms of quantum levels. The spectrum of black hole's quasinormal modes can be re-analysed by introducing a black hole's effective temperature which takes into account the fact that, as shown by Parikh and Wilczek, the radiation spectrum cannot be strictly thermal. This issue changes in a fundamental way the physical understanding of such a spectrum and enables a re-examination of various results in the literature which realizes important modifies on quantum physics of black holes. In particular, the formula of the horizon's area quantization and the number of quanta of area result modified becoming functions of the quantum "overtone" number n. Consequently, the famous formula of Bekenstein-Hawking entropy, its sub-leading corrections and the number of microstates are also modified. Black hole's entropy results a function of the quantum overtone number too. We emphasize that this is the first time that black hole's entropy is directly connected with a quantum number. Previous results in the literature are re-obtained in the limit n \to \infty.Comment: 10 pages,accepted for publication in Journal of High Energy Physics. Comments are welcom

Model order reduction for left ventricular mechanics via congruency training

Computational models of the cardiovascular system and specifically heart function are currently being investigated as analytic tools to assist medical practice and clinical trials. To achieve clinical utility, models should be able to assimilate the diagnostic multi-modality data available for each patient and generate consistent representations of the underlying cardiovascular physiology. While finite element models of the heart can naturally account for patient-specific anatomies reconstructed from medical images, optimizing the many other parameters driving simulated cardiac functions is challenging due to computational complexity. With the goal of streamlining parameter adaptation, in this paper we present a novel, multifidelity strategy for model order reduction of 3-D finite element models of ventricular mechanics. Our approach is centered around well established findings on the similarity between contraction of an isolated muscle and the whole ventricle. Specifically, we demonstrate that simple linear transformations between sarcomere strain (tension) and ventricular volume (pressure) are sufficient to reproduce global pressure-volume outputs of 3-D finite element models even by a reduced model with just a single myocyte unit. We further develop a procedure for congruency training of a surrogate low-order model from multiscale finite elements, and we construct an example of parameter optimization based on medical images. We discuss how the presented approach might be employed to process large datasets of medical images as well as databases of echocardiographic reports, paving the way towards application of heart mechanics models in the clinical practice. © 2020 Di Achille et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.19-14- 00134Russell Sage Foundation, RSFSK and OS were funded by RSF (http:// www.rscf.ru/en/) as described below. Part of this work was carried out within the framework of the IIF UrB RAS government assignment and was partially supported by the UrFU Competitiveness Enhancement Program (agreement 02. A03.21.0006) as well as the RSF grant (No. 19-14- 00134). The Uran supercomputer at IMM UrB RAS was used for part of the model calculations. IBM provided support in the form of salaries for authors PA, JP, JK and VG but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the "author contributions" section

Extreme Quiescent Variability of the Transient Neutron Star Low-mass X-ray Binary EXO 1745-248 in Terzan 5

EXO 1745-248 is a transient neutron-star low-mass X-ray binary that resides in the globular cluster Terzan 5. We studied the transient during its quiescent state using 18 Chandra observations of the cluster acquired between 2003 and 2016. We found an extremely variable source, with a luminosity variation in the 0.5-10 keV energy range of $\sim3$ orders of magnitude (between $3\times10^{31}$ erg s$^{-1}$ and $2\times10^{34}$ erg s$^{-1}$) on timescales from years down to only a few days. Using an absorbed power-law model to fit its quiescent spectra, we obtained a typical photon index of $\sim1.4$, indicating that the source is even harder than during outburst and much harder than typical quiescent neutron stars if their quiescent X-ray spectra are also described by a single power-law model. This indicates that EXO 1745-248 is very hard throughout the entire observed X-ray luminosity range. At the highest luminosity, the spectrum fits better when an additional (soft) component is added to the model. All these quiescent properties are likely related to strong variability in the low-level accretion rate in the system. However, its extreme variable behavior is strikingly different from the one observed for other neutron star transients that are thought to still accrete in quiescence. We compare our results to these systems. We also discuss similarities and differences between our target and the transitional millisecond pulsar IGR J18245-2452, which also has hard spectra and strong variability during quiescence.Comment: Accepted for publication in MNRA

Single- and double-beta decay Fermi-transitions in an exactly solvable model

An exactly solvable model suitable for the description of single and double-beta decay processes of the Fermi-type is introduced. The model is equivalent to the exact shell-model treatment of protons and neutrons in a single j-shell. Exact eigenvalues and eigenvectors are compared to those corresponding to the hamiltonian in the quasiparticle basis (qp) and with the results of both the standard quasiparticle random phase approximation (QRPA) and the renormalized one (RQRPA). The role of the scattering term of the quasiparticle hamiltonian is analyzed. The presence of an exact eigenstate with zero energy is shown to be related to the collapse of the QRPA. The RQRPA and the qp solutions do not include this zero-energy eigenvalue in their spectra, probably due to spurious correlations. The meaning of this result in terms of symmetries is presented.Comment: 29 pages, 9 figures included in a Postsript file. Submitted to Physcal Review

The use of wet-laid techniques to obtain flax nonwovens with different thermoplastic binding fibers for technical insulation applications

[EN] In this work, the wet-laid technique has been used to obtain flax nonwovens thermally bonded with different contents of polyvinyl alcohol (PVA) and bicomponent polyamide 6/copolyamide (PA6/CoPA) fibers in the 10-30 wt.% range. Scanning electron microscopy has been used to evaluate the formation of interlock points through melted polymer and flax fibers. Volume porosity has been estimated through determination of thickness and surface mass. Tensile strength and elongation at break have been determined on longitudinal (preferential) and transversal directions to evaluate anisotropy. The sound absorption properties of stacked sheets of flax: PVA and flax: PA6/CoPA nonwovens have been evaluated. In addition, the thermal insulating properties of individual nonwovens have been obtained. Mechanical characterization shows slight anisotropy. The absorption coefficient is interesting in the medium frequencies range, and relatively low thermal conductivity and thermal resistance values are obtained with these nonwovens (in the 0.020-0.025Wm(-1) K-1 range for flax: PVA nonwovens and in the 0.09-0.10Wm(-1) K-1 range for flax: PA6/CoPA nonwovens). By taking into account these features, these nonwoven substrates could find interesting applications as sound absorbers and/or thermal insulation materials in technical applications.This work is part of the project IPT-310000-2010-037, "ECOTEXCOMP: Research and development of textile structures useful as reinforcement of composite materials with marked ecological character", and was supported by the "Ministerio de Ciencia e Innovacion", with a grant of (sic)189,540.20, within the Plan Nacional de Investigacion Cientifica, Desarrollo e Innovacion Tecnologica 2008-2011 and funded by the European Union through FEDER funds, Technology Fund 2007-2013 and Operational Programme on R + D + i for and on behalf of the companies. The project is also known as "WET-TEX: Implementacion de la tecnologia wet-laid en el desarrollo de nuevos textiles medico-sanitario" with expedient number IMIDIC/2010/137 (total grant of (sic)284,400) and the project "WET-TEX II: Implementacion de la tecnologia wet-laid en la investigacion y desarrollo de paneles para aplicaciones tecnicas a partir de residuos procedentes de la industria textil" with expedient number IMDEEA/2011/167 (total grant of (sic)255,000) funded by IMPIVA and cofunded (80%) by the European Union through FEDER funds, Valencian Community Operational 2007-2012.Fages, E.; Cano, MA.; Gironés, S.; Boronat Vitoria, T.; Fenollar Gimeno, OÁ.; Balart Gimeno, RA. (2013). The use of wet-laid techniques to obtain flax nonwovens with different thermoplastic binding fibers for technical insulation applications. Textile Research Journal. 83(4):426-437. https://doi.org/10.1177/0040517512454183S42643783

Endothelin-1 Predicts Hemodynamically Assessed Pulmonary Arterial Hypertension in HIV Infection.

BackgroundHIV infection is an independent risk factor for PAH, but the underlying pathogenesis remains unclear. ET-1 is a robust vasoconstrictor and key mediator of pulmonary vascular homeostasis. Higher levels of ET-1 predict disease severity and mortality in other forms of PAH, and endothelin receptor antagonists are central to treatment, including in HIV-associated PAH. The direct relationship between ET-1 and PAH in HIV-infected individuals is not well described.MethodsWe measured ET-1 and estimated pulmonary artery systolic pressure (PASP) with transthoracic echocardiography (TTE) in 106 HIV-infected individuals. Participants with a PASP ≥ 30 mmHg (n = 65) underwent right heart catheterization (RHC) to definitively diagnose PAH. We conducted multivariable analysis to identify factors associated with PAH.ResultsAmong 106 HIV-infected participants, 80% were male, the median age was 52 years and 77% were on antiretroviral therapy. ET-1 was significantly associated with higher values of PASP [14% per 0.1 pg/mL increase in ET-1, p = 0.05] and PASP ≥ 30 mmHg [PR (prevalence ratio) = 1.24, p = 0.012] on TTE after multivariable adjustment for PAH risk factors. Similarly, among the 65 individuals who underwent RHC, ET-1 was significantly associated with higher values of mean pulmonary artery pressure and PAH (34%, p = 0.003 and PR = 2.43, p = 0.032, respectively) in the multivariable analyses.ConclusionsHigher levels of ET-1 are independently associated with HIV-associated PAH as hemodynamically assessed by RHC. Our findings suggest that excessive ET-1 production in the setting of HIV infection impairs pulmonary endothelial function and contributes to the development of PAH

Some Applications of Thermal Field Theory to Quark-Gluon Plasma

The lecture provides a brief introduction of thermal field theory within imaginary time formalism, the Hard Thermal Loop perturbation theory and some of its application to the physics of the quark-gluon plasma, possibly created in relativistic heavy ion collisions.Comment: 17 pages, 12 figures : Lectures given in "Workshop on Hadron Physics" during March 7-17, 2005, Puri, Indi

Towards Free Trade in Agriculture

Agriculture seems to be a difficult sector to manage for most governments. Developing countries face tough dilemmas in deciding on appropriate price policies to stimulate food production and maintain stable, preferably low, prices for poor consumers. Governments in developed countries face similar difficult decisions. They are called upon to give income guarantees to farmers whose incomes are unstable and relatively low when compared to those in the nonagricultural sector. These guarantees often lead to ever-increasing budgetary outlays and unwanted agricultural surpluses. High prices make new investments and the application of new technologies more attractive than world prices warrant, and a process is set in motion where technological innovation attains a momentum of its own, in turn requiring price policies that maintain their rates of return. Surpluses are disposed of with subsidies in domestic markets or in the international market. Price competition reduces the market share of other exporters, who may be efficient producers, unless they are willing to engage in subsidy competition. This lowers export earnings and farm incomes or depletes the public resources of developing countries that export competing products. Retaliatory measures have led to frictions and further distortions of world prices. Every so often the major agricultural exporters -- the USA, the EC, Australia, or Canada -- accuse one another of unfair intervention. Though they have agreed to discuss agricultural trade liberalization under GATT negotiations, if anything, the expenditure on farm support has continued to increase in both the EC and the USA. Some developing countries do benefit from the subsidized disposal of surplus cereals on the world market. This, however, might be only a short-term gain. Low prices are a disincentive to their own producers and lead, in the long run, to an unsustainable dependence on imports, as appears to be the case in many parts of Africa. Also, these benefits of cheap cereals may not offset the loss of markets, such as the sugar market, which is important to a large number of developing countries. Against that background and in the light of the fact that many countries have agreed to discuss agricultural trade liberalization under GATT, it is important to assess the consequences of agricultural trade liberalization. It should increase efficiency at the global level as countries adjust their production more in line with their comparative advantages. However, in the absence of compensating transfers, some countries may lose under liberalization. An assessment of efficiency gains at the global level and gains and losses of countries can provide some insight into the degree to which their own production and trade have become distorted and how large the adjustment costs may be. Several questions are relevant here: what if the developed market economies remove border protection? But also: what consequences can be expected from the removal of border protection by developing countries only? (This is an issue that can be usefully analyzed as it belongs to the regular package of adjustment policies recommended by the World Bank and the IMF.) What would be the impact of simultaneous liberalization by all market economies? Who would gain and who would lose? This book reports on a study that explored these questions using a system of empirically estimated national agricultural policy models linked together through trade and capital transfers. A general equilibrium approach is followed for both the national models and the international linkage. Thus, behavioral responses of consumers and producers, as well as the responses of government policies to changes in world market conditions, are accounted for. We call this system of models the Basic Linked System (BLS). It consists of 18 national models, two models of regions -- namely, the EC and the Council for Mutual Economic Assistance (CMEA) -- and 14 somewhat similar models of groups of countries. Together these cover all the nations of the world. We believe that the BLS is particularly suited -- at least, better than any other existing analytic tool -- for the analysis of issues related to agricultural trade liberalization and self-sufficiency. The present study differs from other available studies on trade liberalization in combining all the following features: a general equilibrium approach is applied to both the national and international levels; most of the parameters are empirically estimated; a number of agricultural commodities are distinguished; nations are distinguished; and a rich variety of policy instruments for national governments is permitted, including tariffs, trade, quotas, taxes, transfers, and stock operations. The existence of these features can significantly alter policy conclusions derived from the analysis