8,771 research outputs found

    Effect of Martian Suspended Dust on Albedo Measurements from the MGS-TES Data

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    Suspended dust on Mars influences albedo measurements by orbiting instruments, but not necessary the real surface albedo. The aim of this study is to characterize the role of suspended aerosols on albedo measurement by remote sensing instruments

    Self-T-Dual Brane Cosmology and the Cosmological Constant Problem

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    We consider a codimension-one brane embedded in a gravity-dilaton bulk action, whose symmetries are compatible with T-duality along the space-like directions parallel to the brane, and the bulk time-like direction. The equations of motions in the string frame allow for a smooth background obtained by the union of two symmetric patches of AdS space. The Poincar\'{e} invariance of the solution appears to hold independently of the value of the brane vacuum energy, through a self-tuning property of the dilaton ground state. Moreover, the effective cosmology displays a bounce, at which the scale factor does not shrink to zero. Finally, by exploiting the T-duality symmetry, we show how to construct an ever-expanding Universe, along the lines of the Pre-Big Bang scenario.Comment: Minor corrections, comments & references added. Accepted for publicatio

    Analisis Pengetahuan Konseptual, Prosedural, dan Metakognitif Siswa Melalui Pembelajaran Integrasi Flipped Classroom dan PBL

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    Student-centered learning (SCL) is a learning approach that not only encourages to how student constructs their conceptual knowledge, but also to achieve the involvement of their knowledge in daily activity, in forms procedural and metacognitive knowledge. Flipped classroom learning models marked by reversed learning activities syntax between class and home, which promoted student to active self-learning, before turn into face to face class meeting. Problem Based Learning (PBL) model provides students to apply their knowledge to formulate strategy and solution in facing their problem. Flipped classroom or PBL, both are student-centered learning models that triggers student to self-constructed knowledge actively and student’s curiosity to solve their problem. This paper attempts to analyze the influence of integration flipped classroom and PBL on conceptual, procedural, and metacognitive knowledge on Linear Motion subject. This research is a quasi experimental model with post-test only control design. The population in this study were all students of class X MIPA SMA Negeri 37 Jakarta in the 2019-2020 school year. The sample in this study were students of class X MIPA 1 as the experimental class and class X MIPA 2 as the control class. The sample was taken using cluster sampling technique. The results obtained showed that the percentage of conceptual, procedural and metacognitive knowledge of the experimental class was 88.9%; 77.8%; and 88.9% which is higher than the control class with the respective percentage 66.7%; 55.8%; and 75%. The integration of the flipped classroom and PBL models can be applied to materials other than Linear Motion to improve conceptual, procedural, and metacognitive knowledge

    Analisis Pengetahuan Konseptual, Prosedural, dan Metakognitif Siswa Melalui Pembelajaran Integrasi Flipped Classroom dan PBL

    Get PDF
    Student-centered learning (SCL) is a learning approach that not only encourages to how student constructs their conceptual knowledge, but also to achieve the involvement of their knowledge in daily activity, in forms procedural and metacognitive knowledge. Flipped classroom learning models marked by reversed learning activities syntax between class and home, which promoted student to active self-learning, before turn into face to face class meeting. Problem Based Learning (PBL) model provides students to apply their knowledge to formulate strategy and solution in facing their problem. Flipped classroom or PBL, both are student-centered learning models that triggers student to self-constructed knowledge actively and student’s curiosity to solve their problem. This paper attempts to analyze the influence of integration flipped classroom and PBL on conceptual, procedural, and metacognitive knowledge on Linear Motion subject. This research is a quasi experimental model with post-test only control design. The population in this study were all students of class X MIPA SMA Negeri 37 Jakarta in the 2019-2020 school year. The sample in this study were students of class X MIPA 1 as the experimental class and class X MIPA 2 as the control class. The sample was taken using cluster sampling technique. The results obtained showed that the percentage of conceptual, procedural and metacognitive knowledge of the experimental class was 88.9%; 77.8%; and 88.9% which is higher than the control class with the respective percentage 66.7%; 55.8%; and 75%. The integration of the flipped classroom and PBL models can be applied to materials other than Linear Motion to improve conceptual, procedural, and metacognitive knowledge

    Estimating truncation effects of quantum bosonic systems using sampling algorithms

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    To simulate bosons on a qubit- or qudit-based quantum computer, one has to regularize the theory by truncating infinite-dimensional local Hilbert spaces to finite dimensions. In the search for practical quantum applications, it is important to know how big the truncation errors can be. In general, it is not easy to estimate errors unless we have a good quantum computer. In this paper, we show that traditional sampling methods on classical devices, specifically Markov Chain Monte Carlo, can address this issue for a rather generic class of bosonic systems with a reasonable amount of computational resources available today. As a demonstration, we apply this idea to the scalar field theory on a two-dimensional lattice, with a size that goes beyond what is achievable using exact diagonalization methods. This method can be used to estimate the resources needed for realistic quantum simulations of bosonic theories, and also, to check the validity of the results of the corresponding quantum simulations

    A multi-objective DIRECT algorithm for ship hull optimization

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    The paper is concerned with black-box nonlinear constrained multi-objective optimization problems. Our interest is the definition of a multi-objective deterministic partition-based algorithm. The main target of the proposed algorithm is the solution of a real ship hull optimization problem. To this purpose and in pursuit of an efficient method, we develop an hybrid algorithm by coupling a multi-objective DIRECT-type algorithm with an efficient derivative-free local algorithm. The results obtained on a set of “hard” nonlinear constrained multi-objective test problems show viability of the proposed approach. Results on a hull-form optimization of a high-speed catamaran (sailing in head waves in the North Pacific Ocean) are also presented. In order to consider a real ocean environment, stochastic sea state and speed are taken into account. The problem is formulated as a multi-objective optimization aimed at (i) the reduction of the expected value of the mean total resistance in irregular head waves, at variable speed and (ii) the increase of the ship operability, with respect to a set of motion-related constraints. We show that the hybrid method performs well also on this industrial problem

    Endovascular Treatment of a Ruptured Pararenal Abdominal Aortic Aneurysm in a Patient With Coronavirus Disease-2019: Suggestions and Case Report

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    The aim of this report is to discuss emergent repair for complex aortic diseases in patients affected by novel coronavirus pneumonia (coronavirus disease-2019 [COVID-19]), describing a case of ruptured pararenal aortic aneurysm. An eighty-year-old man with COVID-19 was admitted for ruptured aneurysm of the pararenal aorta and hemorrhagic shock. Endovascular repair was chosen, and a proximal extension of the previous abdominal endograft was performed with parallel stents in the right renal artery and the superior mesenteric artery. Endovascular treatment and early anticoagulation are the key for success for vascular emergencies in patients with COVID-19, despite the risk of late endoleak

    Critical thermodynamics of the two-dimensional +/-J Ising spin glass

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    We compute the exact partition function of 2d Ising spin glasses with binary couplings. In these systems, the ground state is highly degenerate and is separated from the first excited state by a gap of size 4J. Nevertheless, we find that the low temperature specific heat density scales as exp(-2J/T), corresponding to an ``effective'' gap of size 2J; in addition, an associated cross-over length scale grows as exp(J/T). We justify these scalings via the degeneracy of the low-lying excitations and by the way low energy domain walls proliferate in this model

    Conservation status of milkcaps (Basidiomycota, russulales, russulaceae), with notes on poorly known species

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    Mycological conservation has finally come of age. The increasingly recognized crucial role played by fungi in ecosystem functioning has spurred a wave of attention toward the status of fungal populations across the world. Milkcaps (Lactarius and Lactifluus) are a large and widespread group of ectomycorrhizal basidiomycetes; besides their ecological relevance, many species of milkcaps are of socio-economic significance because of their edibility. We analysed the presence of milkcaps in fungal Red Lists worldwide, ending up with an impressive list of 265 species assessed in various threat categories. Lactarius species are disproportionally red-listed with respect to Lactifluus (241 versus 24 species). Two species of Lactarius (L. maruiaensis and L. ogasawarashimensis) are currently considered extinct, and four more are regionally extinct; furthermore, 37 species are critically endangered at least in part of their distribution range. Several problems with the red-listing of milkcaps have been identified in this study, which overall originate from a poor understanding of the assessed species. Wrong or outdated nomenclature has been applied in many instances, and European names have been largely used to indicate taxa occurring in North America and Asia, sometimes without any supporting evidence. Moreover, several rarely recorded and poorly known species, for which virtually no data exist, have been included in Red Lists in some instances. We stress the importance of a detailed study of the species of milkcaps earmarked for insertion in Red Lists, either at national or international level, in order to avoid diminishing the value of this important conservation tool
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