5,096 research outputs found

    Minimally non-local nucleon-nucleon potentials with chiral two-pion exchange including Δ\Delta's

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    We construct a coordinate-space chiral potential, including Δ\Delta-isobar intermediate states in its two-pion-exchange component. The contact interactions entering at next-to-leading and next-to-next-to-next-to-leading orders (Q2Q^2 and Q4Q^4, respectively, QQ denoting generically the low momentum scale) are rearranged by Fierz transformations to yield terms at most quadratic in the relative momentum operator of the two nucleons. The low-energy constants multiplying these contact interactions are fitted to the 2013 Granada database, consisting of 2309 pppp and 2982 npnp data (including, respectively, 148 and 218 normalizations) in the laboratory-energy range 0--300 MeV. For the total 5291 pppp and npnp data in this range, we obtain a χ2\chi^2/datum of roughly 1.3 for a set of three models characterized by long- and short-range cutoffs, RLR_{\rm L} and RSR_{\rm S} respectively, ranging from (RL,RS)=(1.2,0.8)(R_{\rm L},R_{\rm S})=(1.2,0.8) fm down to (0.8,0.6)(0.8,0.6) fm. The long-range (short-range) cutoff regularizes the one- and two-pion exchange (contact) part of the potential.Comment: 32 pages, 19 figures, accepted for publication as a Regular Article in Physical Review

    Phenomenological High Precision Neutron-Proton Delta-Shell Potential

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    We provide a successful fit for proton-neutron scattering below pion production threshold up to LAB energies of 350 MeV. We use seven high-quality fits based on potentials with different forms as a measure of the systematic uncertainty. We represent the interaction as a sum of delta-shells in configuration space below the 3fm and a charge dependent one pion exchange potential above 3fm together with magnetic and vacuum polarization effects. Special attention is paid to estimate the errors of the phenomenological interaction.Comment: 5 pages, 2 figures. Comments and one figure with differential observables adde

    Energy balance of mussels Mytilus galloprovincialis: the effect of length and age

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    Clearance and ingestion rates, absorption efficiencies and respiration rates were measured in mussels Mytilus galloprovincialis Lmk of different lengths (53 to 89 mm) and age (10 to 24 mo) from cultivation rafts in the Ría de Arosa (Galicia, Spain). The experiments were carried out either in the laboratory, using monoalgal food (Isochrysis galbana) with an organic content of 91%, or under natural conditions of food availability in cultivation rafts with seston, the organic content of which ranged from 33 to 69%. Food concentrations ranged from 0.57 to 1.00 mg l-1 of total particulate matter (TPM), a load which is below the threshold for the production of pseudofaeces in Mytilus. These experiments proved that the ingestion rate (IR = mg TPM h-1) of food increases with the size of the mussel (measured as g of soft-tissue dry weight [DW]) according to the power equation IR = 12.661DW0.619, this model accounting for over 90% of the variance of the IR. Behavioural patterns that tended to maintain constant IR regardless of the density of the food were observed. Absorption efficiency (AE) is positively related to the organic content (OC) of the food according to the following hyperbolic equation: AE = 1.015 - 0.163(1/OC) (r = 0.940). AE is independent of mussel size for most of the size range used in this study, but there is a critical length around 85 mm, above which there is a noticeable decrease of AE. Metabolic expenditure, measured in terms of oxygen consumption standarized per unit of dry weight of flesh, tends to increase with the age of the mussel. The results obtained led to the conclusion that physiological traits such as the regulation of ingestion or differences in AE between groups do not explain the differences in growth between mussels of the same age. These differences must therefore be due to the limited food and space available as a result of the large numbers of mussels on the cultivation rafts and the agglomeration of mussels on the cultivation ropes.Versión de editor

    Orthogonal basis with a conicoid first mode for shape specification of optical surfaces: Reply

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    We present some comments to the paper “Orthogonal basis with a conicoid first mode for shape specification of optical surfaces: comment.

    Estudio científico del Mihrab de la antigua mezquita de Almería

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    En este trabajo se realiza un estudio de los distintos materiales empleados en la construcción, tanto originales como añadidos, las distintas intervenciones rea lizadas en el Mihrab de la antigua Mezquita de Almería. El estudio de las mues tras ha permitido determinar la naturaleza de cada una de ellas, así como la exis tencia de gran cantidad de sales (clomros y sulfatos en su mayoría). Asimismo, se ha obtenido información sobre su micromorfología. porosidad, mayor o me nor grado de cristalinidad y estado de alteración. Finalmente se ha comprobado la aplicación, en época reciente, de consolidantes que han sido responsables del desprendimiento superficial

    Defects in the NC2 repressor affect both canonical and non-coding RNA polymerase II transcription initiation in yeast.

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    BACKGROUND: The formation of the pre-initiation complex in eukaryotic genes is a key step in transcription initiation. The TATA-binding protein (TBP) is a universal component of all pre-initiation complexes for all kinds of RNA polymerase II (RNA pol II) genes, including those with a TATA or a TATA-like element, both those that encode proteins and those that transcribe non-coding RNAs. Mot1 and the negative cofactor 2 (NC2) complex are regulators of TBP, and it has been shown that depletion of these factors in yeast leads to defects in the control of transcription initiation that alter cryptic transcription levels in selected yeast loci. RESULTS: In order to cast light on the molecular functions of NC2, we performed genome-wide studies in conditional mutants in yeast NC2 essential subunits Ydr1 and Bur6. Our analyses show a generally increased level of cryptic transcription in all kinds of genes upon depletion of NC2 subunits, and that each kind of gene (canonical or ncRNAs, TATA or TATA-like) shows some differences in the cryptic transcription pattern for each NC2 mutant. CONCLUSIONS: We conclude that NC2 plays a general role in transcription initiation in RNA polymerase II genes that is related with its known TBP interchange function from free to promoter bound states. Therefore, loss of the NC2 function provokes increases in cryptic transcription throughout the yeast genome. Our results also suggest functional differences between NC2 subunits Ydr1 and Bur6

    Modificación hidrotérmica del almidón de yuca para su empleo como estabilizador de helados

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    En el trabajo se desarrolla un procedimiento de modificación física de almidón nativo de yuca a través de un tratamiento hidrotérmico en la zona previa a la gelatinización, de la cual no existen reportes de experimentación. El objetivo es determinar la influencia de las principales variables del proceso sobre el comportamiento reológico, con el propósito de ser empleado como estabilizador en la Industria heladera. Se alcanzaron buenos resultados reológicos con una concentración de 6% p/p de almidón nativo a 56 0C. El material obtenido se usó en formulaciones de helados, sustituyendo parte de los productos convencionales con efectos muy positivos en cuanto a la evaluación sensorial y el índice de aireación. Los resultados alcanzados permiten establecer perspectivas para el empleo de almidones modificados de yuca cuyo tratamiento hidrotérmico en la zona previa a la gelatinización ofrece efectos positivos, como estabilizante de suspensiones acuosas, similares a los que se alcanzan con almidones pregelatinizados, además con la ventaja de obtener el producto modificado con mayor facilidad

    Normative Emotional Agents: a viewpoint paper

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    [EN] Human social relationships imply conforming to the norms, behaviors and cultural values of the society, but also socialization of emotions, to learn how to interpret and show them. In multiagent systems, much progress has been made in the analysis and interpretation of both emotions and norms. Nonetheless, the relationship between emotions and norms has hardly been considered and most normative agents do not consider emotions, or vice-versa. In this article, we provide an overview of relevant aspects within the area of normative agents and emotional agents. First we focus on the concept of norm, the different types of norms, its life cycle and a review of multiagent normative systems. Secondly, we present the most relevant theories of emotions, the life cycle of an agent¿s emotions, and how emotions have been included through computational models in multiagent systems. Next, we present an analysis of proposals that integrate emotions and norms in multiagent systems. From this analysis, four relationships are detected between norms and emotions, which we analyze in detail and discuss how these relationships have been tackled in the reviewed proposals. Finally, we present a proposal for an abstract architecture of a Normative Emotional Agent that covers these four norm-emotion relationships.This work was supported by the Spanish Government project TIN2017-89156- R, the Generalitat Valenciana project PROMETEO/2018/002 and the Spanish Goverment PhD Grant PRE2018-084940.Argente, E.; Del Val, E.; Pérez-García, D.; Botti Navarro, VJ. (2022). Normative Emotional Agents: a viewpoint paper. IEEE Transactions on Affective Computing. 13(3):1254-1273. https://doi.org/10.1109/TAFFC.2020.3028512S1254127313

    Minimally Nonlocal Nucleon-Nucleon Potentials With Chiral Two-Pion Exchange Including Δ Resonances

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    We construct a coordinate-space chiral potential, including Δ -isobar intermediate states in its two-pion-exchange component up to order Q3 (Q denotes generically the low momentum scale). The contact interactions entering at next-to-leading and next-to-next-to-next-to-leading orders (Q2 and Q4 , respectively) are rearranged by Fierz transformations to yield terms at most quadratic in the relative momentum operator of the two nucleons. The low-energy constants multiplying these contact interactions are fitted to the 2013 Granada database, consisting of 2309 pp and 2982 np data (including, respectively, 148 and 218 normalizations) in the laboratory-energy range 0–300 MeV. For the total 5291 pp and np data in this range, we obtain a χ2 /datum of roughly 1.3 for a set of three models characterized by long- and short-range cutoffs, RL and RS , respectively, ranging from (RL ,RS)=(1.2, 0.8) fm down to (0.8,0.6) fm. The long-range (short-range) cutoff regularizes the one- and two-pion exchange (contact) part of the potential
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