Turning noise into signal: learning from the scatter in the Hubble diagram

The supernova (SN) Hubble diagram residual contains valuable information on both the present matter power spectrum and its growth history. In this paper we show that this information can be retrieved with precision by combining both peculiar velocity and weak-lensing analysis on the data. To wit, peculiar velocity induces correlations on the nearby SN while lensing induces a non-Gaussian dispersion in faraway objects. We show that both effects have almost orthogonal degeneracies and discuss how they can be extracted simultaneously from the data. We analyze the JLA supernova catalog in a 14-dimensional parameter space, assuming a flexible growth-rate index $\gamma$. We arrive at the following marginalized constraints: $\sigma_8 = 0.65^{+0.23}_{-0.37}$ and $\gamma = 1.38^{+1.7}_{-0.65}$. Assuming instead GR as the correct gravitation theory (and thus $\gamma \equiv 0.55$), the constraints in $\sigma_8$ tighten further: $\sigma_8 = 0.40^{+0.21}_{-0.23}$. We show that these constraints complement well the ones obtained from other datasets and that they could improve substantially with more SNe.Comment: v2: Real data results corrected; forecast for future data added; discussion extended. v3: Improved discussion; matches published version. 8 figs 15 page

Cosmological Parameter Estimation from SN Ia data: a Model-Independent Approach

We perform a model independent reconstruction of the cosmic expansion rate based on type Ia supernova data. Using the Union 2.1 data set, we show that the Hubble parameter behaviour allowed by the data without making any hypothesis about cosmological model or underlying gravity theory is consistent with a flat LCDM universe having H_0 = 70.43 +- 0.33 and Omega_m=0.297 +- 0.020, weakly dependent on the choice of initial scatter matrix. This is in closer agreement with the recently released Planck results (H_0 = 67.3 +- 1.2, Omega_m = 0.314 +- 0.020) than other standard analyses based on type Ia supernova data. We argue this might be an indication that, in order to tackle subtle deviations from the standard cosmological model present in type Ia supernova data, it is mandatory to go beyond parametrized approaches

Under the same sky with Amanar

Due to its technological, scientific and cultural dimensions, astronomy is a unique discipline to help achieve the United Nations Sustainable Development Goals. According to the United Nations High Commissioner for Refugees (UNHCR), there are currently nearly 30 million refugees in the world. While there are many (and very necessary) programmes supporting their basic needs, different indicators suggest that the resolution to refugee and internal displacement situations require not only humanitarian interventions, but also development-led actions. One of these initiatives is Amanar: Under the Same Sky, a project designed to support the Sahrawi refugee community by using astronomy to enhance their resilience and engagement in the community, through skill development and self-empowerment activities.Comment: 5 pages, 2 figures. Comment published on Nature Astronom

Distributed incremental fingerprint identification with reduced database penetration rate using a hierarchical classification based on feature fusion and selection

Fingerprint recognition has been a hot research topic along the last few decades, with many applications and ever growing populations to identify. The need of flexible, fast identification systems is therefore patent in such situations. In this context, fingerprint classification is commonly used to improve the speed of the identification. This paper proposes a complete identification system with a hierarchical classification framework that fuses the information of multiple feature extractors. A feature selection is applied to improve the classification accuracy. Finally, the distributed identification is carried out with an incremental search, exploring the classes according to the probability order given by the classifier. A single parameter tunes the trade-off between identification time and accuracy. The proposal is evaluated over two NIST databases and a large synthetic database, yielding penetration rates close to the optimal values that can be reached with classification, leading to low identification times with small or no accuracy loss

The stiffness of elastomeric surfaces influences the mechanical properties of endothelial cells

Optimal characterization of the mechanical properties of both cells and their surrounding is an issue of major interest. Indeed, cell function and development are strongly influenced by external stimuli. Furthermore, a change in cell mechanics might, in some cases, associate with diseases or malfunctioning. In this work, atomic force microscopy (AFM) was applied to examine the mechanical properties of the silicone elastomer polydimethylsiloxane (PDMS) a common substrate in cell culture. Force spectroscopy analysis was done over different specimens of this elastomeric material containing varying ratios of resin to cross-linker in its structure (5:1, 10:1, 20:1, 30:1 and 50:1), which impacts the final material properties (e.g., stiffness, elasticity). To quantify the mechanical properties of the PDMS, factors as the modulus of Young, the maximum adhesive forces as well as both relaxation amplitudes and times upon constant height contact of the tip (dwell time different of zero) were calculated from the different segments forming the force curves. It is demonstrated that the material stiffness is increased by prior oxygen plasma treatment of the sample, required for hydrophilic switching, contrarily to what observed for its adhesiveness. Subsequent incubation of endothelial HUVEC cells on top of these plasma treated PDMS systems yields minor variation in cell mechanics in comparison to those obtained on a glass reference, on which cells show much higher spreading tendency and, by extension, a remarkable membrane hardening. Thus, surface wettability turns a factor of higher relevance than substrate stiffness inducing variations in the cell mechanics.Comment: manuscript (12 pages, 4 figures, 2 tables), supplementary information (2 pages and 3 figures), the main results of the manuscript are based on a master thesi

DPD-DFF: a dual phase distributed scheme with double fingerprint fusion for fast and accurate identification in large databases

Nowadays, many companies and institutions need fast and reliable identification systems that are able to deal with very large databases. Fingerprints are among the most used biometric traits for identification. In the current literature there are fingerprint matching algorithms that are focused on efficiency, whilst others are based on accuracy. In this paper we propose a flexible dual phase identification method, called DPD-DFF, that combines two fingers and two matchers within a hybrid fusion scheme to obtain both fast and accurate results. Different alternatives are designed to find a trade-off between runtime and accuracy that can be further tuned with a single parameter. The experiments show that DPD-DFF obtains very competitive results in comparison with the state-of-the-art score fusion techniques, especially when dealing with large databases or impostor fingerprints

Presentación de quiste gigante de ovario en paciente adolescente

Introducción: los tumores ováricos constituyen el tercer grupo de tumores en la mujer; la experiencia clínica revela alta incidencia durante la etapa climatérica, siendo infrecuente en las primeras décadas de la vida.Presentación del caso: se trata de paciente femenina de 13 años de edad y color de piel blanca, que acude a consulta de Ginecología del Hospital Provincial Pediátrico “Pepe Portilla”, provincia Pinar del Río, refiriendo aumento de volumen en la región abdominal. Al examen físico se constató abdomen globuloso, con masa tumoral en todo hemiabdomen inferior, doloroso a la palpación superficial y profunda en hipogastrio, tumor central redondeado desde el hipogastrio hasta aproximadamente 5 cm por encima del ombligo, móvil, renitente, de bordes bien definidos y lisos, se realizan exámenes complementarios y se decide cirugía, encontrándose quiste ovárico gigante.Conclusiones: los quistes ováricos son diagnosticados de modo fortuito, pues la mayoría son asintomáticos, la simple exploración clínica permite arribar al diagnóstico presuntivo; es la ultrasonografía el examen de elección para su estudio, permitiendo manejo oportuno y confort en los pacientes afectos, también puede presentarse en las primeras décadas de la vida

Electrical Properties and Electromagnetic Interference Shielding Effectiveness of Interlayered Systems Composed by Carbon Nanotube Filled Carbon Nanofiber Mats and Polymer Composites

The demand for multifunctional requirements in aerospace, military, automobile, sports, and energy applications has encouraged the investigation of new composite materials. This study focuses on the development of multiwall carbon nanotube (MWCNT) filled polypropylene composites and carbon nanofiber composite mats. The developed systems were then used to prepare interlayered composites that exhibited improved electrical conductivity and electromagnetic interference (EMI) shielding efficiency. MWCNT-carbon nanofiber composite mats were developed by centrifugally spinning mixtures of MWCNT suspended in aqueous poly(vinyl alcohol) solutions. The developed nanofibers were then dehydrated under sulfuric acid vapors and then heat treated. Interlayered samples were fabricated using a nanoreinforced polypropylene composite as a matrix and then filled with carbon fiber composite mats. The in-plane and through-plane electrical conductivity of an eight-layered flexible carbon composite (0.65 mm thick) were shown to be 6.1 and 3.0 × 10−2 S·cm−1, respectively. The EMI shielding effectiveness at 900 MHz increased from 17 dB for the one-layered composite to 52 dB for the eight-layered composite. It was found that the reflection of the electromagnetic waves was the dominating mechanism for EMI shielding in the developed materials. This study opens up new opportunities for the fabrication of novel lightweight materials that are to be used in communication systems

Benzotriazole-based multidonor-acceptor systems as attractive two-photon absorption dye platforms

Pyrazine-decorated benzotriazole cores allow the orthogonal combination of two dipolar systems within a single molecule. A series of this type of derivatives was synthesized and their photophysical features were studied. The properties of these compounds showed remarkable differences in function depending on the substitution in the pyrazine ring of the benzotriazole core. Furthermore, the two-photon absorption property (2PA) was studied to determine the structure-properties relationship for the reported compounds. The best dye achieved a crosssection of 1532 GM, which was higher than values previously obtained for similar D-π-A-π-D benzotriazole derivatives. TD-DFT calculations, which supported the experimental observations, indicating the interaction between the two dipolar systems was responsible for enhancing the 2 PA properties and favoring bathochromic shifts.PCI2019-111825-2, PID2019-104293GB-I00, UMA18-FEDERJA-007, SBPLY/17/180501/000189, PID2020-119636GB-I00 , RED2018-102331-T, Universidad de Málaga / CBU