Fractal analysis of the galaxy distribution in the redshift range 0.45 < z < 5.0

Evidence is presented that the galaxy distribution can be described as a fractal system in the redshift range of the FDF galaxy survey. The fractal dimension $D$ was derived using the FDF galaxy volume number densities in the spatially homogeneous standard cosmological model with $\Omega_{m_0}=0.3$, $\Omega_{\Lambda_0}=0.7$ and H_0=70 \; \mbox{km} \; {\mbox{s}}^{-1} \; {\mbox{Mpc}}^{-1}. The ratio between the differential and integral number densities $\gamma$ and $\gamma^\ast$ obtained from the red and blue FDF galaxies provides a direct method to estimate $D$, implying that $\gamma$ and $\gamma^\ast$ vary as power-laws with the cosmological distances. The luminosity distance $d_{\scriptscriptstyle L}$, galaxy area distance $d_{\scriptscriptstyle G}$ and redshift distance $d_z$ were plotted against their respective number densities to calculate $D$ by linear fitting. It was found that the FDF galaxy distribution is characterized by two single fractal dimensions at successive distance ranges. Two straight lines were fitted to the data, whose slopes change at $z \approx 1.3$ or $z \approx 1.9$ depending on the chosen cosmological distance. The average fractal dimension calculated using $\gamma^\ast$ changes from $\langle D \rangle=1.4^{\scriptscriptstyle +0.7}_{\scriptscriptstyle -0.6}$ to $\langle D \rangle=0.5^{\scriptscriptstyle +1.2}_{\scriptscriptstyle -0.4}$ for all galaxies, and $D$ decreases as $z$ increases. Small values of $D$ at high $z$ mean that in the past galaxies were distributed much more sparsely and the large-scale galaxy structure was then possibly dominated by voids. Results of Iribarrem et al. (2014, arXiv:1401.6572) indicating similar fractal features with $\langle D \rangle =0.6 \pm 0.1$ in the far-infrared sources of the Herschel/PACS evolutionary probe (PEP) at $1.5 \lesssim z \lesssim 3.2$ are also mentioned.Comment: LaTex, 15 pages, 28 figures, 4 tables. To appear in "Physica A

Changes in structure and aroma release from starch-aroma systems upon α-amylase addition

The influence of starch hydrolysis by α-amylase addition on structural properties and aroma release from starch-aroma systems was studied. A food model system composed of aqueous tapioca starch dispersion (4g dry starch/100g dispersion) and one aroma compound (menthone) was investigated. Structure breakdown and related changes in starch fraction (amylose) were measured by rheology and iodine-binding. Menthone release from the aroma-starch system in the headspace was followed by proton transfer reaction-mass spectrometry (PTR-MS) upon starch hydrolysis. A slightly higher viscosity was found for the starch-menthone system compared to the starch system without menthone upon α-amylase addition. One could hypothesise that menthone acts as a kind of nucleation agent for inducing structure build-up of starch segments, hindering starch degradation. An extensive aroma release from aroma-starch systems upon α-amylase addition was expected, but, instead, just a slight volatile increase was found after a starch hydrolysis time of 60min. It is suggested that aroma release is the result of several superimposed effects ranging from viscosity effects to interactions between aroma compounds and starch degradation product

Evolución de la capacidad explicativa de los modelos de valoración de activos basados en factores en la determinación del coste de capital

[EN] The recent research on asset pricing shows that the higher liquidity that results from the globalization of financial markets has significantly reduced the returns tied to many market anomaly-based strategies. However, in general, that research does not evaluate the effects that the mitigation of market anomalies may imply on the performance of the classic asset pricing models. On this basis, in this paper we study to what extent the lower returns provided by market anomaly-based strategies imply better performance of those models. Hence, the main purpose of our study is to compare the performance over time of some of the most prominent asset pricing models, namely, the CAPM and the Fama and French three- and five-factor models, on the European and US equity markets, using return series that cover more than 30 years. Our results show that, although the CAPM is the model with the worst performance in explaining excess returns in all periods both in Europe and US, the model has increased its explanatory power in the recent years principally due to the attenuation of classic market anomalies, such as the size effect or the value effect. Furthermore, our results show that the CAPM correctly prices the three classic Fama and French factors for the years 2006-2021, which explains the best performance of the model for that time interval. Our results have impor[ES] Dentro del ámbito de la valoración de activos, investigaciones recientes ponen de manifiesto cómo el incremento de la liquidez de los mercados financieros por razón de la globalización se está traduciendo en una paulatina reducción de los diferenciales de rentabilidad proporcionados por diferentes estrategias basadas en anomalías del mercado. No obstante, tales investigaciones no analizan en general el impacto que dicha reducción tiene sobre el funcionamiento de los modelos clásicos de valoración de activos. Sobre esta base, este trabajo se desarrolla al objeto de analizar en qué medida el proceso de atenuación de las anomalías de mercado se traduce en un incremento de la capacidad explicativa de dichos modelos. Así, el principal propósito de este estudio es realizar una comparativa en el tiempo entre los principales modelos de valoración de activos, concretamente el CAPM y los modelos de tres y cinco factores de Fama y French, en los mercados de acciones europeo y estadounidense, haciendo uso de series de rendimientos de más de 30 años. Los resultados obtenidos muestran que, a pesar de que tanto a nivel europeo como estadounidense y en todos los periodos estudiados, el CAPM es el modelo con un peor comportamiento a la hora de explicar los excesos de rentabilidad, el modelo ve incrementada su capacidad explicativa en los años más recientes debido a la atenuación de anomalías clásicas del mercado, como son el efecto tamaño o el efecto valor. Más aún, nuestros resultados confirman que el CAPM es capaz de valorar correctamente los tres factores clásicos de Fama y French para los años 2006-2021, lo que explica el mejor funcionamiento del modelo para ese intervalo de tiempo. Nuestros resultados tienen importantes implicaciones para la gestión y análisis de inversiones bursátiles, así como para la determinación del coste de capital de las empresas.We gratefully acknowledge the funding granted by the European Social Fund and the Education and Research Service of the Madrid regional government, through grant PEJ16/SOC/AI162

Rudiments of Holography

An elementary introduction to Maldacena's AdS/CFT correspondence is given, with some emphasis in the Fefferman-Graham construction. This is based on lectures given by one of us (E.A.) at the Universidad Autonoma de Madrid.Comment: 60 pages, additional misprints corrected, references adde

CVD of CrO2: towards a lower temperature deposition process

We report on the synthesis of highly oriented a-axis CrO2 films onto (0001) sapphire by atmospheric pressure CVD from CrO3 precursor, at growth temperatures down to 330 degree Celsius, i.e. close to 70 degrees lower than in published data for the same chemical system. The films keep the high quality magnetic behaviour as those deposited at higher temperature, which can be looked as a promising result in view of their use with thermally sensitive materials, e.g. narrow band gap semiconductors.Comment: 13 pages, 4 figure

NEETs in Latin America and the Caribbean: Skills, Aspirations, and Information

This paper studies the role of cognitive skills, socioemotional skills, aspirations and expectations on the likelihood of being NEET (not in education, employment or training) using a novel sample of 15 to 24 year old residents of seven Latin American and Caribbean countries. After controlling for sociodemographic household conditions, we find that numeracy and literacy skills, core self‐evaluation, extraversion and educational aspirations are robust correlates of being NEET. We also find cross country heterogeneity. That is, in some countries, passion and perseverance for long‐term goals, neuroticism and labour market information biases are additional factors associated with being NEET

COPD and cardiovascular disease

COPD is one of the major public health problems in people aged 40 years or above. It is currently the 4th leading cause of death in the world and projected to be the 3rd leading cause of death by 2020. COPD and cardiac comorbidities are frequently associated. They share common risk factors, pathophysiological processes, signs and symptoms, and act synergistically as negative prognostic factors. Cardiac disease includes a broad spectrum of entities with distinct pathophysiology, treatment and prognosis. From an epidemiological point of view, patients with COPD are particularly vulnerable to cardiac disease. Indeed, mortality due to cardiac disease in patients with moderate COPD is higher than mortality related to respiratory failure. Guidelines reinforce that the control of comorbidities in COPD has a clear benefit over the potential risk associated with the majority of the drugs utilized. On the other hand, the true survival benefits of aggressive treatment of cardiac disease and COPD in patients with both conditions have still not been clarified. Given their relevance in terms of prevalence and prognosis, we will focus in this paper on the management of COPD patients with ischemic coronary disease, heart failure and dysrhythmia.Novartis Portugal Novartisinfo:eu-repo/semantics/publishedVersio