A characterization of dual quermassintegrals and the roots of dual steiner polynomials

For any $I\subset\mathbb{R}$ finite with $0\in I$, we provide a characterization of those tuples $(\omega_i)_{i\in I}$ of positive numbers which are dual querma\ss integrals of two star bodies. It turns out that this problem is related to the moment problem. Based on this relation we also get new inequalities for the dual querma\ss integrals. Moreover, the above characterization will be the key tool in order to investigate structural properties of the set of roots of dual Steiner polynomials of star bodies

Effective equations for isotropic quantum cosmology including matter

Effective equations often provide powerful tools to develop a systematic understanding of detailed properties of a quantum system. This is especially helpful in quantum cosmology where several conceptual and technical difficulties associated with the full quantum equations can be avoided in this way. Here, effective equations for Wheeler-DeWitt and loop quantizations of spatially flat, isotropic cosmological models sourced by a massive or interacting scalar are derived and studied. The resulting systems are remarkably different from that given for a free, massless scalar. This has implications for the coherence of evolving states and the realization of a bounce in loop quantum cosmology.Comment: 42 page

Effective constraints of loop quantum gravity

Within a perturbative cosmological regime of loop quantum gravity corrections to effective constraints are computed. This takes into account all inhomogeneous degrees of freedom relevant for scalar metric modes around flat space and results in explicit expressions for modified coefficients and of higher order terms. It also illustrates the role of different scales determining the relative magnitude of corrections. Our results demonstrate that loop quantum gravity has the correct classical limit, at least in its sector of cosmological perturbations around flat space, in the sense of perturbative effective theory.Comment: 44 pages, 6 figure

Improving Attitude Words Classification for Opinion Mining using Word Embedding

[EN] Recognizing and classifying evaluative expressions is an important issue of sentiment analysis. This paper presents a corpus-based method for classifying attitude types (Affect, Judgment and Appreciation) and attitude orientation (positive and negative) of words in Spanish relying on the Attitude system of the Appraisal Theory. The main contribution lies in exploring large and unlabeled corpora using neural network word embedding techniques in order to obtain semantic information among words of the same attitude and orientation class. Experimental results show that the proposed method achieves a good effectiveness and outperforms the state of the art for automatic classification of attitude words in Spanish language.The work of the fourth author was partially supported by the SomEMBED TIN2015-71147-C2-1-P research project (MINECO/FEDER).Ortega-Bueno, R.; Medina-Pagola, JE.; Muñiz-Cuza, CE.; Rosso, P. (2019). Improving Attitude Words Classification for Opinion Mining using Word Embedding. Lecture Notes in Computer Science. 11401:971-982. https://doi.org/10.1007/978-3-030-13469-3_112S9719821140

Combinatorial RNA Design: Designability and Structure-Approximating Algorithm

In this work, we consider the Combinatorial RNA Design problem, a minimal instance of the RNA design problem which aims at finding a sequence that admits a given target as its unique base pair maximizing structure. We provide complete characterizations for the structures that can be designed using restricted alphabets. Under a classic four-letter alphabet, we provide a complete characterization of designable structures without unpaired bases. When unpaired bases are allowed, we provide partial characterizations for classes of designable/undesignable structures, and show that the class of designable structures is closed under the stutter operation. Membership of a given structure to any of the classes can be tested in linear time and, for positive instances, a solution can be found in linear time. Finally, we consider a structure-approximating version of the problem that allows to extend bands (helices) and, assuming that the input structure avoids two motifs, we provide a linear-time algorithm that produces a designable structure with at most twice more base pairs than the input structure.Comment: CPM - 26th Annual Symposium on Combinatorial Pattern Matching, Jun 2015, Ischia Island, Italy. LNCS, 201

Fragility Curves for Thin-Walled Cold-Formed Steel Wall Frames Affected by Ground Settlements Due to Land Subsidence

Land subsidence phenomenon due to ground water withdrawal is a current problem in many places around the world, particularly in the shallows of Mexico. This causes ground differential settlements that affect structures, mainly dwellings and buildings based on reinforced concrete and masonry. Eventually, these structural materials do not exhibit an adequate performance beyond a certain level of angular distortion. This work presents the results about a study regarding the performance of thin-walled cold-formed steel wall frames with different sheathing systems affected by angular distortions simulating ground differential settlements due to land subsidence. The wall frames are composed by vertical (studs) and horizontal elements (tracks), with different sheathing systems: polystyrene, OSB, gypsum and calcium silicate. By means of experimental testing of wall frames subjected to monotonic lateral loads, the rotational stiffness was obtained for the wall frames with polystyrene. Likewise the rotational stiffness of the other wall frame systems was calculated based on the data provided by other author’s publications. On the other hand, by means of numerical simulation, all the wall frame systems were modeled in structural analysis software, calibrating them based on the rotational stiffness. Also, the moment-rotation curves were calculated for the studs and tracks based on the direct strength method. A non-linear static pull down analysis was performed producing several degrees of angular distortion simulating ground settlements for all the wall frames sheathing systems. With the data acquired fragility curves were calculated according three levels of damage for the wall frames with different sheathing system

Cosmological vector modes and quantum gravity effects

In contrast to scalar and tensor modes, vector modes of linear perturbations around an expanding Friedmann--Robertson--Walker universe decay. This makes them largely irrelevant for late time cosmology, assuming that all modes started out at a similar magnitude at some early stage. By now, however, bouncing models are frequently considered which exhibit a collapsing phase. Before this phase reaches a minimum size and re-expands, vector modes grow. Such modes are thus relevant for the bounce and may even signal the breakdown of perturbation theory if the growth is too strong. Here, a gauge invariant formulation of vector mode perturbations in Hamiltonian cosmology is presented. This lays out a framework for studying possible canonical quantum gravity effects, such as those of loop quantum gravity, at an effective level. As an explicit example, typical quantum corrections, namely those coming from inverse densitized triad components and holonomies, are shown to increase the growth rate of vector perturbations in the contracting phase, but only slightly. Effects at the bounce of the background geometry can, however, be much stronger.Comment: 20 page

Micro-channel–based high specific power lithium target

A micro-channel–based heat sink has been produced and tested. The device has been developed to be used as a Lithium target for the LENOS (Legnaro Neutron Source) facility and for the production of radioisotope. Nevertheless, applications of such device can span on many areas: cooling of electronic devices, diode laser array, automotive applications etc. The target has been tested using a proton beam of 2.8MeV energy and delivering total power shots from 100W to 1500W with beam spots varying from 5mm2 to 19mm2. Since the target has been designed to be used with a thin deposit of lithium and since lithium is a low-melting-point material, we have measured that, for such application, a specific power of about 3kW/cm2 can be delivered to the target, keeping the maximum surface temperature not exceeding 150◦C