Generalization of the coupled dipole method to periodic structures

We present a generalization of the coupled dipole method to the scattering of light by arbitrary periodic structures. This new formulation of the coupled dipole method relies on the same direct-space discretization scheme that is widely used to study the scattering of light by finite objects. Therefore, all the knowledge acquired previously for finite systems can be transposed to the study of periodic structures.Comment: 5 pages, 2 figures, and 1 tabl

Health related quality of life scales in women diagnosed with gynecological and breast cancer: The role of resilience. A systematic review

Objective: Resilience and health-related quality of life are factors to be valued today in all types of patients for their relationship to well-being and health. Any stressful situation can significantly impact quality of life and resilience and there are numerous scales to rate these aspects. The main objective of this review is to describe the most used health-related quality of life and resilience scales in gynecological and breast cancer patients to highlight the limitations. Data sources: A review of literature in Pubmed, MEDLINE, Cochrane Database and Google Scholar was carried out to identify articles on health-related quality of life in oncological patients published in English between 2000 and 2020. Methods of study selection: The review was done following the PRISMA guidelines. Tabulation: A total of 460 papers were identified using MeSH terms but finally, according to the inclusion and exclusion criteria, we evaluated 41. Integration and results: Questionnaires have a good performance to quantify quality of life and resilience in oncological patients in general. However, most publications were not focused on patients with gynecological cancer. Conclusions: Due to the particularities of the group of patients with gynecologic and breast cancer secondary to their treatment significantly affecting several areas and domains, it is necessary to validate specific scales for them in order to offer these patients the correct management of their disease at all levels. The role of resilience, premature and iatrogenic menopause and mutilating surgeries are essential to understand the uniqueness of health-related quality of life in gynecological and breast cancer patients. ©2021 The Author(s)

Astrophysical Ionizing Radiation and the Earth: A Brief Review and Census of Intermittent Intense Sources

Cosmic radiation backgrounds are a constraint on life, and their distribution will affect the Galactic Habitable Zone. Life on Earth has developed in the context of these backgrounds, and characterizing event rates will elaborate the important influences. This in turn can be a base for comparison with other potential life-bearing planets. In this review we estimate the intensities and rates of occurrence of many kinds of strong radiation bursts by astrophysical entities ranging from gamma-ray bursts at cosmological distances to the Sun itself. Many of these present potential hazards to the biosphere: on timescales long compared with human history, the probability of an event intense enough to disrupt life on the land surface or in the oceans becomes large. We enumerate the known sources of radiation and characterize their intensities at the Earth and rates or upper limits on these quantities. When possible, we estimate a "lethal interval", our best estimate of how often a major extinction-level event is probable given the current state of knowledge; we base these estimates on computed or expected depletion of stratospheric ozone. In general, moderate level events are dominated by the Sun, but the far more severe infrequent events are probably dominated by gamma-ray bursts and supernovae. We note for the first time that so-called "short-hard" gamma-ray bursts are a substantial threat, comparable in magnitude to supernovae and greater than that of the higher-luminosity long bursts considered in most past work. Given their precursors, short bursts may come with little or no warning.Comment: to be published in Astrobiolog

Evaluación del valor nutritivo y los costos de producción del heno en pie y del ensilaje de sorgos nervadura marrón o BMR (Brown Middle Rib)

Para evaluar si la calidad y los costos de producción (CP) del ensilaje de sorgo nervadura marrón o BMR (Brown Middle Rib) son superiores a los de este cultivo diferido (heno en pie), se diseñaron dos ensayos. Uno, con sorgo BMR comercial “Nutritop”, y el otro “Para Silo”. Para cada ensayo se establecieron dos tratamientos con el mismo sorgo BMR (T1 ensilado y T2 diferido (heno en pie). Se sembraron dos parcelas, de 70 ha con cada uno de los sorgos. En la mitad de cada parcela (35 ha) se realizó un ensilaje de planta entera y en la otra, se dejó diferido. Se utilizó un diseño completamente aleatorizado, con diez repeticiones. Se analizaron las variables proteína bruta, digestibilidad de la MS, FND, lignina, carbohidratos solubles y almidón. Las digestibilidades de los diferidos fueron superiores con respecto a los ensilajes (65.5 vs 64.1 y 62.1 vs 60.1 para el 1° y 2° ensayo, respectivamente). Los carbohidratos solubles y almidón, también resultaron superiores (P < 0.05). No se encontraron diferencias significativas en los niveles de PB y lignina. Mientras que el costo de producción de los diferidos fue muy inferior (-546.15 %). La menor calidad de los ensilajes se puede explicar por el alto nivel de efluentes generados, que arrastran al suelo las sustancias solubles de alta calidad. Los sorgos BMR diferidos mantienen una calidad superior, especialmente energética, además de sus bajos costos de producción, condiciones que los convierten en una buena alternativa para la época de seca o clima frío.EEA BordenaveFil: Fernandez Mayer, Anibal. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bordenave. Agencia de Extensión Rural Coronel Pringles; ArgentinaFil: Stuart Montalvo, René. Instituto de Ciencia Animal; CubaFil: Chongo, Bertha. Instituto de Ciencia Animal; CubaFil: Martín Méndez, P.C. Instituto de Ciencia Animal; Cub

Finalización de novillos Abeerden Angus con cereales forrajeros de invierno y con grano de cereal en bajas proporciones

La finalización de novillos pesados (> 450 kg cabeza-1) se realiza normalmente en corral, debido a las altas exigencias energéticas. Sin embargo, por los costos elevados de producción (CP) los ranchos o fincas medianos y pequeños están limitados en su utilización. El adecuado balance energía-proteína de los cereales forrajeros encañados, ricos en carbohidratos solubles (CNES), y bajos en proteína soluble (PBS) (CNES PBS-1>1.0), con aporte extra de energía de granos de cereal, permiten obtener altas ganancias de peso (GDP). El objetivo de este experimento fue terminar animales pesados de raza británica con avena (Avena sativa) encañada y bajas proporciones de granos (0.4% del PV). El estudio se dividió en dos etapas: 1) 143 novillos con 386.06 kg durante 70 d, 2) subdividida en dos períodos: 234 novillos, con 383.4 kg durante 61 d, y 180 novillos, con 416.0 kg cabeza-1 durante 68 d. Se midió la calidad nutricional (CN), la GDP, eficiencia de conversión (ECv) y CP. La unidad experimental fue el animal, con 20 repeticiones por etapa. Se probaron modelos lineales y no lineales (variable PV) y se seleccionó el modelo cuadrático (lineal). Todos los parámetros resultaron significativos (0.95 y 0.97 R2; 42.42 y 26.78 CME, respectivamente). Se utilizaron 1.82 kg de grano de maíz y 1.38 y 1.84 kg de cabeza-1 de sorgo, respectivamente. La relación CNES PBS-1 estuvo en 1.30 y 1.68. Las GDP fueron 1.04, 1.223 y 1.103 kg cabeza-1 d-1, respectivamente. Las ECv consistieron en 10.78, 8.68 y 9.69 kg MS alimento kg carne-1. Los CP fueron 0.90, 0.68 y 0.89 u$s kg producido-1, respectivamente. Se terminaron animales pesados a pasto, con baja proporción de grano y un CP inferior al engorde en corral.EEA BordenaveFil: Fernandez Mayer, Anibal. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bordenave. Agencia de Extensión Rural Coronel Pringles; ArgentinaFil: Stuart Montalvo, René. Instituto de Ciencia Animal; CubaFil: Chongo, Bertha. Instituto de Ciencia Animal; CubaFil: Martín Méndez, P.C. Instituto de Ciencia Animal; Cub

Dynamic structure factor of the Ising model with purely relaxational dynamics

We compute the dynamic structure factor for the Ising model with a purely relaxational dynamics (model A). We perform a perturbative calculation in the $\epsilon$ expansion, at two loops in the high-temperature phase and at one loop in the temperature magnetic-field plane, and a Monte Carlo simulation in the high-temperature phase. We find that the dynamic structure factor is very well approximated by its mean-field Gaussian form up to moderately large values of the frequency $\omega$ and momentum $k$. In the region we can investigate, $k\xi \lesssim 5$, $\omega \tau \lesssim 10$, where $\xi$ is the correlation length and $\tau$ the zero-momentum autocorrelation time, deviations are at most of a few percent.Comment: 21 pages, 3 figure

Linear Response, Validity of Semi-Classical Gravity, and the Stability of Flat Space

A quantitative test for the validity of the semi-classical approximation in gravity is given. The criterion proposed is that solutions to the semi-classical Einstein equations should be stable to linearized perturbations, in the sense that no gauge invariant perturbation should become unbounded in time. A self-consistent linear response analysis of these perturbations, based upon an invariant effective action principle, necessarily involves metric fluctuations about the mean semi-classical geometry, and brings in the two-point correlation function of the quantum energy-momentum tensor in a natural way. This linear response equation contains no state dependent divergences and requires no new renormalization counterterms beyond those required in the leading order semi-classical approximation. The general linear response criterion is applied to the specific example of a scalar field with arbitrary mass and curvature coupling in the vacuum state of Minkowski spacetime. The spectral representation of the vacuum polarization function is computed in n dimensional Minkowski spacetime, and used to show that the flat space solution to the semi-classical Einstein equations for n=4 is stable to all perturbations on distance scales much larger than the Planck length.Comment: 22 pages: This is a significantly expanded version of gr-qc/0204083, with two additional sections and two new appendices giving a complete, explicit example of the semi-classical stability criterion proposed in the previous pape

Analytical treatment of SUSY Quasi-normal modes in a non-rotating Schwarzschild black hole

We use the Fock-Ivanenko formalism to obtain the Dirac equation which describes the interaction of a massless 1/2-spin neutral fermion with a gravitational field around a Schwarzschild black hole (BH). We obtain approximated analytical solutions for the eigenvalues of the energy (quasi-normal frequencies) and their corresponding eigenstates (quasi-normal states). The interesting result is that all the excited states [and their supersymmetric (SUSY) partners] have a purely imaginary frequency, which can be expressed in terms of the Hawking temperature. Furthermore, as one expects for SUSY Hamiltonians, the isolated bottom state has a real null energy eigenvalue.Comment: Version to be published in European Physical Journal

Naked Singularity Formation In f(R) Gravity

We study the gravitational collapse of a star with barotropic equation of state $p=w\rho$ in the context of $f({\mathcal R})$ theories of gravity. Utilizing the metric formalism, we rewrite the field equations as those of Brans-Dicke theory with vanishing coupling parameter. By choosing the functionality of Ricci scalar as $f({\mathcal R})=\alpha{\mathcal R}^{m}$, we show that for an appropriate initial value of the energy density, if $\alpha$ and $m$ satisfy certain conditions, the resulting singularity would be naked, violating the cosmic censorship conjecture. These conditions are the ratio of the mass function to the area radius of the collapsing ball, negativity of the effective pressure, and the time behavior of the Kretschmann scalar. Also, as long as parameter $\alpha$ obeys certain conditions, the satisfaction of the weak energy condition is guaranteed by the collapsing configuration.Comment: 15 pages, 4 figures, to appear in GR

ISG15 and ISGylation is required for pancreatic cancer stem cell mitophagy and metabolic plasticity

Pancreatic cancer stem cells (PaCSCs) drive pancreatic cancer tumorigenesis, chemoresistance and metastasis. While eliminating this subpopulation of cells would theoretically result in tumor eradication, PaCSCs are extremely plastic and can successfully adapt to targeted therapies. In this study, we demonstrate that PaCSCs increase expression of interferon-stimulated gene 15 (ISG15) and protein ISGylation, which are essential for maintaining their metabolic plasticity. CRISPR-mediated ISG15 genomic editing reduces overall ISGylation, impairing PaCSCs self-renewal and their in vivo tumorigenic capacity. At the molecular level, ISG15 loss results in decreased mitochondrial ISGylation concomitant with increased accumulation of dysfunctional mitochondria, reduced oxidative phosphorylation (OXPHOS) and impaired mitophagy. Importantly, disruption in mitochondrial metabolism affects PaCSC metabolic plasticity, making them susceptible to prolonged inhibition with metformin in vivo. Thus, ISGylation is critical for optimal and efficient OXPHOS by ensuring the recycling of dysfunctional mitochondria, and when absent, a dysregulation in mitophagy occurs that negatively impacts PaCSC stemness