The chemical composition of the Orion star-forming region: II. Stars, gas, and dust: the abundance discrepancy conundrum

We re-examine the recombination/collisional emission line (RL/CEL) nebular abundance discrepancy problem in the light of recent high-quality abundance determinations in young stars in the Orion star-forming region. We re-evaluate the CEL and RL abundances of several elements in the Orion nebula and estimate the associated uncertainties, taking into account the uncertainties in the ionization correction factors for unseen ions. We estimate the amount of oxygen trapped in dust grains for several scenarios of dust formation. We compare the resulting gas+dust nebular abundances with the stellar abundances of a sample of 13 B-type stars from the Orion star-forming region (Ori\,OB1), analyzed in Papers I and III of this series. We find that the oxygen nebular abundance based on recombination lines agrees much better with the stellar abundances than the one derived from the collisionally excited lines. This result calls for further investigation. If the CEL/RL abundance discrepancy were caused by temperature fluctuations in the nebula, as argued by some authors, the same kind of discrepancy should be seen for the other elements, such as C, N and Ne, which is not what we find in the present study. Another problem is that with the RL abundances, the energy balance of the Orion nebula is not well understood. We make some suggestions concerning the next steps to undertake to solve this problem.Comment: 11 pages, 8 tables, 5 figures (To be published in A&A

Self-assembly of supramolecular chemoenzymatic poly-l-phenylalanine

The self-assembly behavior of chemoenzymatic high molecular weight (ca. 30 000 Da) poly-L-phenylalanine (ePLP) and the nano-morphologies thereof are investigated. Interestingly, this supramolecular ePLP changes from a non-ordered secondary structure when solubilized in water to an a-helix with the addition of only 1 vol% HFIP co-solvent, and at a relatively low concentration (0.5 mg mL-1). The results also indicate a temperature-dependent structural stabilization, wherein the self-assembly process is mainly governed by hydrogen bonding. The analyses evidence self-assembly under controlled conditions to obtain nanotubes with an average diameter of 0.21 ± 0.04 µm, and above 100 µm length. Microbeam synchrotron radiation infrared (SRIR) spectroscopy demonstrates parallel orientations of the amide moieties in the a-helical structure, which is extraordinary for this long chain ePLP. The achievement of these highly homogeneous nanotubes is relevant since previous reports only demonstrated this arrangement for end-capped F-moc-containing short oligophenylalanines. In the same way, the conductivity behaviors of the nanotubular structure remained unchanged in the range of 273–313 K demonstrating its stability from hydrogen bonds, and also, direct dielectric measurements reveal a high orientation and stabilization by intra- and intermolecular hydrogen bonds in the nanotubes. These characteristics allow drug delivery assays with tetracycline-loaded nanotubes and further applications are envisaged.Peer ReviewedPostprint (author's final draft

First survey of Wolf-Rayet star populations over the full extension of nearby galaxies observed with CALIFA

The search of extragalactic regions with conspicuous presence of Wolf-Rayet (WR) stars outside the Local Group is challenging task due to the difficulties in detecting their faint spectral features. In this exploratory work, we develop a methodology to perform an automated search of WR signatures through a pixel-by-pixel analysis of integral field spectroscopy (IFS) data belonging to the Calar Alto Legacy Integral Field Area survey, CALIFA. This technique allowed us to build the first catalogue of Wolf-Rayet rich regions with spatially-resolved information, allowing to study the properties of these complexes in a 2D context. The detection technique is based on the identification of the blue WR bump (around He II 4686 {\AA}, mainly associated to nitrogen-rich WR stars, WN) and the red WR bump (around C IV 5808 {\AA} and associated to carbon-rich WR stars, WC) using a pixel-by-pixel analysis. We identified 44 WR-rich regions with blue bumps distributed in 25 galaxies of a total of 558. The red WR bump was identified only in 5 of those regions. We found that the majority of the galaxies hosting WR populations in our sample are involved in some kind of interaction process. Half of the host galaxies share some properties with gamma-ray burst (GRB) hosts where WR stars, as potential candidates to being the progenitors of GRBs, are found. We also compared the WR properties derived from the CALIFA data with stellar population synthesis models, and confirm that simple star models are generally not able to reproduce the observations. We conclude that other effects, such as the binary star channel (which could extend the WR phase up to 10 Myr), fast rotation or other physical processes that causes the loss of observed Lyman continuum photons, are very likely affecting the derived WR properties, and hence should be considered when modelling the evolution of massive stars.Comment: 33 pages, accepted for publication in A&

Imprints of galaxy evolution on H ii regions Memory of the past uncovered by the CALIFA survey

H ii regions in galaxies are the sites of star formation and thus particular places to understand the build-up of stellar mass in the universe. The line ratios of this ionized gas are frequently used to characterize the ionization conditions. We use the Hii regions catalogue from the CALIFA survey (~5000 H ii regions), to explore their distribution across the classical [OIII]/Hbeta vs. [NII]/Halpha diagnostic diagram, and how it depends on the oxygen abundance, ionization parameter, electron density, and dust attenuation. We compared the line ratios with predictions from photoionization models. Finally, we explore the dependences on the properties of the host galaxies, the location within those galaxies and the properties of the underlying stellar population. We found that the location within the BPT diagrams is not totally predicted by photoionization models. Indeed, it depends on the properties of the host galaxies, their galactocentric distances and the properties of the underlying stellar population. These results indicate that although H ii regions are short lived events, they are affected by the total underlying stellar population. One may say that H ii regions keep a memory of the stellar evolution and chemical enrichment that have left an imprint on the both the ionizing stellar population and the ionized gasComment: 18 pages, 8 figures, accepted for publishing in A&

Information flow during gene activation by signaling molecules: ethylene transduction in Arabidopsis cells as a study system

<p>Abstract</p> <p>Background</p> <p>We study root cells from the model plant <it>Arabidopsis thaliana </it>and the communication channel conformed by the ethylene signal transduction pathway. A basic equation taken from our previous work relates the probability of expression of the gene <it>ERF</it>1 to the concentration of ethylene.</p> <p>Results</p> <p>The above equation is used to compute the Shannon entropy (<it>H</it>) or degree of uncertainty that the genetic machinery has during the decoding of the message encoded by the ethylene specific receptors embedded in the endoplasmic reticulum membrane and transmitted into the nucleus by the ethylene signaling pathway. We show that the amount of information associated with the expression of the master gene <it>ERF</it>1 (Ethylene Response Factor 1) can be computed. Then we examine the system response to sinusoidal input signals with varying frequencies to determine if the cell can distinguish between different regimes of information flow from the environment. Our results demonstrate that the amount of information managed by the root cell can be correlated with the frequency of the input signal.</p> <p>Conclusion</p> <p>The ethylene signaling pathway cuts off very low and very high frequencies, allowing a window of frequency response in which the nucleus reads the incoming message as a sinusoidal input. Out of this window the nucleus reads the input message as an approximately non-varying one. From this frequency response analysis we estimate: a) the gain of the system during the synthesis of the protein ERF1 (~-5.6 dB); b) the rate of information transfer (0.003 bits) during the transport of each new ERF1 molecule into the nucleus and c) the time of synthesis of each new ERF1 molecule (~21.3 s). Finally, we demonstrate that in the case of the system of a single master gene (<it>ERF</it>1) and a single slave gene (<it>HLS</it>1), the total Shannon entropy is completely determined by the uncertainty associated with the expression of the master gene. A second proposition shows that the Shannon entropy associated with the expression of the <it>HLS</it>1 gene determines the information content of the system that is related to the interaction of the antagonistic genes <it>ARF</it>1, 2 and <it>HLS</it>1.</p

In-Line estimation of the standard colour index of citrus fruits using a computer vision system developed for a mobile platform

The final publication is available at Springer via http://dx.doi.org/10.1007/s11947-012-1015-2A key aspect for the consumer when it comes to deciding on a particular product is the colour. In order to make fruit available to consumers as early as possible, the collection of oranges and mandarins begins before they ripen fully and reach their typical orange colour. As a result, they are therefore subjected to certain degreening treatments, depending on their standard colour citrus index at harvest. Recently, a mobile platform that incorporates a computer vision system capable of pre-sorting the fruit while it is being harvested has been developed as an aid in the harvesting task. However, due to the restrictions of working in the field, the computer vision system developed for this machine is limited in its technology and processing capacity compared to conventional systems. This work shows the optimised algorithms for estimating the colour of citrus in-line that were developed for this mobile platform and its performance is evaluated against that of a spectrophotometer used as a reference in the analysis of colour in food. The results obtained prove that our analysis system predicts the colour index of citrus with a good reliability (R2 = 0.925) working in real time. Findings also show that it is effective for classifying harvested fruits in the field according to their colour. © 2012 Springer Science+Business Media New York.This work was partially funded by the INIA through research project RTA2009-00118-C02-01 with the support of European FEDER funds, and by the project PAID-05-11-2745, Vicerectorat d'Investigacio, Universitat Politecnica de Valencia.Vidal, A.; Talens Oliag, P.; Prats-Montalbán, JM.; Cubero García, S.; Albert Gil, FE.; Blasco Ivars, J. (2013). In-Line estimation of the standard colour index of citrus fruits using a computer vision system developed for a mobile platform. Food and Bioprocess Technology. 6(12):3412-3419. https://doi.org/10.1007/s11947-012-1015-2S34123419612Arzate-Vázquez, I., Chanona-Pérez, J. J., Perea-Flores, M. J., Calderón-Domínguez, G., Moreno-Armendáriz, M. A., Calvo, H., Godoy-Calderón, S., Quevedo, R., & Gutiérrez-López, G. (2011). Image processing applied to classification of avocado variety Hass (Persea americana Mill.) during the ripening process. Food and Bioprocess Technology, 4(7), 1307–1313.Blasco, J., Aleixos, N., Cubero, S., Gómez-Sanchis, J., & Moltó, E. (2009). Automatic sorting of satsuma (Citrus unshiu) segments using computer vision and morphological features. Computers and Electronics in Agriculture, 66, 1–8.Campbell, B. L., Nelson, R. G., Ebel, C. E., Dozier, W. A., Adrian, J. L., & Hockema, B. R. (2004). Fruit quality characteristics that affect consumer preferences for satsuma mandarins. HortScience, 39(7), 1664–1669.Cavazza, A., Corradini, C., Rinaldi, M., Salvadeo, P., Borromei, C., & Massini, R. (2012). Evaluation of pasta thermal treatment by determination of carbohydrates, furosine, and color indices. Food and Bioprocess Technology. doi: 10.1007/s11947-012-0906-6 . In-press.Cubero, S., Aleixos, N., Moltó, E., Gómez-Sanchis, J., & Blasco, J. (2011). Advances in machine vision applications for automatic inspection and quality evaluation of fruits and vegetables. Food and Bioprocess Technology, 4(4), 487–504.Cubero, S., Moltó, E., Gutiérrez, A., Aleixos, N., García-Navarrete, O. L., Juste, F., & Blasco, J. (2010). Real-time inspection of fruit on a mobile harvesting platform in field conditions using computer vision. Progress in Agricultural Engineering Science, 6, 1–16.Díaz, R., Faus, G., Blasco, M., Blasco, J., & Moltó, E. (2000). The application of a fast algorithm for the classification of olives by machine vision. Food Research International, 33, 305–309.DOGV (2006) Diari Oficial de la Comunitat Valenciana, 5346, 30321-30328.Gardner, J. L. (2007). Comparison of calibration methods for tristimulus colorimeters. Journal of Research of the National Institute of Standards and Technology, 112, 129–138.Hashim, N., Janius, R. B., Baranyai, L., Rahman, R. A., Osman, A., & Zude, M. (2011). Kinetic model for colour changes in bananas during the appearance of chilling injury symptoms. Food and Bioprocess Technology, 5(8), 2952–2963.HunterLab (2008): Applications note, 8(9), http://www.hunterlab.com/appnotes/an08_96a.pdf . Accessed September 2012.Hutchings, J. B., Luo, R., & Ji, W. (2002). Calibrated colour imaging analysis of food. In D. MacDougall (Ed.), Colour in Food (pp. 352–366). Cambridge: Woodhead Publishing.Jiménez-Cuesta MJ, Cuquerella J & Martínez-Jávega JM (1981) Determination of a color index for citrus fruit degreening. In Proc. of the International Society of Citriculture, Vol. 2, 750-753Kang, S. P., East, A. R., & Trujillo, F. J. (2008). Colour vision system evaluation of bicolour fruit: A case study with ‘B74’ mango. Postharvest Biology and Technology, 49, 77–85.Lang, C., & Hübert, T. (2011). A colour ripeness indicator for apples. Food and Bioprocess Technology, 5(8), 3244–3249.López-Camelo, A. F., & Gómez, P. A. (2004). Comparison of color indexes for tomato ripening. Horticultura Brasileira, 22(3), 534–537. http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-05362004000300006 .López-García, F., Andreu-García, A., Blasco, J., Aleixos, N., & Valiente, J. M. (2010). Automatic detection of skin defects in citrus fruits using a multivariate image analysis approach. Computers and Electronics in Agriculture, 71, 189–197.Lorente, D., Aleixos, N., Gómez-Sanchis, J., Cubero, S., García-Navarrete, O. L., & Blasco, J. (2012). Recent advances and applications of hyperspectral imaging for fruit and vegetable quality assessment. Food and Bioprocess Technology, 5(4), 1121–1142.Mendoza, F., Dejmek, P., & Aguilera, J. M. (2006). Calibrated color measurements of agricultural foods using image analysis. Postharvest Biology and Technology, 41, 285–295.Montgomery, D. C. (2005). Design and analysis of experiments, 6th ed. Tempe: Wiley.Noboru, O., & Robertson, A. R. (2005). Colorimetry. West Sussex: Wiley.Pathare, P. B., Opara, U. L., & Al-Said, F. A. (2012). Colour measurement and analysis in fresh and processed foods: a review. Food and Bioprocess Technology. doi: 10.1007/s11947-012-0867-9 . In-press.Quevedo, R. A., Aguilera, J. M., & Pedreschi, F. (2010). Colour of salmon fillets by computer vision and sensory panel. 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Dynamic equivalence between atomic and colloidal liquids

We show that the kinetic-theoretical self-diffusion coefficient of an atomic fluid plays the same role as the short-time self-diffusion coefficient D_S in a colloidal liquid, in the sense that the dynamic properties of the former, at times much longer than the mean free time, and properly scaled with D_S, will indistinguishable from those of a colloidal liquid with the same interaction potential. One important consequence of such dynamic equivalence is that the ratio D_L/ D_S of the long-time to the short-time self-diffusion coefficients must then be the same for both, an atomic and a colloidal system characterized by the same inter-particle interactions. This naturally extends to atomic fluids a well-known dynamic criterion for freezing of colloidal liquids[Phys. Rev. Lett. 70, 1557 (1993)]. We corroborate these predictions by comparing molecular and Brownian dynamics simulations on (soft- and hard-sphere) model systems, representative of what we may refer to as the "hard-sphere" dynamic universality class

Uso del agua de coco (Cocos nucifera) como terapia electrolítica intravenosa en caninos deshidratados

The objective of this study was to evaluate the use of coconut water (AC) applied intravenously in dogs. In a first phase the sterility and isotonicity of the CA was evaluated. In a second phase, the hematological changes produced 24 hours after the application of CA by intraperitoneal route in rats were evaluated. In a third phase the application of AC applied intravenously was evaluated in dogs with and without physical activity (n=20, per group), where the hematological values, pH and chlorine and sodium levels were determined before and after its application, as well as the heart rate, respiratory rate and temperature at the beginning, at 15, 30, 45, 60 minutes after the start of the application and 30 minutes after the application of the AC. The results showed that AC is sterile and isotonic, did not produce significant alterations in the hematological values of rats or in dogs without physical activity. However, dogs with physical activity showed a reduction in hematocrit at 30 minutes after application and a slight reduction in sodium levels.El presente trabajo tuvo como objetivo evaluar el uso del agua de coco (AC) aplicada por vía intravenosa en perros. En una primera fase se evaluó la esterilidad e isotonicidad del AC. En una segunda fase se evaluaron los cambios hematológicos producidos 24 horas pos-aplicación del AC por vía intraperitoneal en ratas. En una tercera fase se evaluó la aplicación de AC vía intravenosa en perros con y sin actividad física (n=20, por grupo), donde se determinaron los valores hematológicos, pH y niveles de cloro y sodio antes y después de su aplicación, así como la frecuencia cardiaca, frecuencia respiratoria y temperatura al inicio, a los 15, 30, 45, 60 minutos de iniciada la aplicación y 30 minutos después de la aplicación del AC. Los resultados muestran que el AC es estéril e isotónico, no produjo alteraciones significativas en los valores hematológicos de las ratas ni en los perros sin actividad física. Sin embargo, los perros con actividad física mostraron una reducción del hematocrito a los 30 minutos pos-aplicación y una leve reducción de los niveles de sodio

Spatially Resolved Star Formation Main Sequence of Galaxies in the Califa Survey

The "main sequence of galaxies" - defined in terms of the total star formation rate ψ versus the total stellar mass M ∗ - is a well-studied tight relation that has been observed at several wavelengths and at different redshifts. All earlier studies have derived this relation from integrated properties of galaxies. We recover the same relation from an analysis of spatially resolved properties, with integral field spectroscopic (IFS) observations of 306 galaxies from the CALIFA survey. We consider the SFR surface density in units of log(M o yr-1 Kpc-2) and the stellar mass surface density in units of log(M o Kpc-2) in individual spaxels that probe spatial scales of 0.5-1.5 Kpc. This local relation exhibits a high degree of correlation with small scatter (σ = 0.23 dex), irrespective of the dominant ionization source of the host galaxy or its integrated stellar mass. We highlight (i) the integrated star formation main sequence formed by galaxies whose dominant ionization process is related to star formation, for which we find a slope of 0.81 ± 0.02; (ii) for the spatially resolved relation obtained with the spaxel analysis, we find a slope of 0.72 ± 0.04; and (iii) for the integrated main sequence, we also identified a sequence formed by galaxies that are dominated by an old stellar population, which we have called the retired galaxies sequence.Fil: Cano Díaz, M.. Universidad Nacional Autonoma de Mexico. Instituto de Astronomia; MéxicoFil: Sánchez, S. F.. Universidad Nacional Autonoma de Mexico. Instituto de Astronomia; MéxicoFil: Zibetti, S.. Osservatorio Astrofisico di Arcetri; Italia. Istituto Nazionale di Astrofisica; ItaliaFil: Ascasibar, Y.. Universidad Autónoma de Madrid; España. Consejo Superior de Investigaciones Científicas; EspañaFil: Bland Hawthorn, J.. University of Sydney; AustraliaFil: Ziegler, B.. Universidad de Viena; AustriaFil: González Delgado, R. M.. Instituto de Astrofísica de Andalucía; España. Consejo Superior de Investigaciones Científicas; EspañaFil: Walcher, C.J.. Gobierno de la República Federal de Alemania. Max Planck Institut für Astrophysik; AlemaniaFil: García Benito, Rubén. Instituto de Astrofísica de Andalucía; España. Consejo Superior de Investigaciones Científicas; EspañaFil: Mast, Damian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; ArgentinaFil: Mendoza Pérez, M. A.. Instituto de Astrofísica de Andalucía; España. Consejo Superior de Investigaciones Científicas; EspañaFil: Falcón Barroso, J.. Instituto de Astrofísica de Canarias; España. Universidad de La Laguna; EspañaFil: Galbany, Lluís. Millennium Institute of Astrophysics; Chile. Universidad de Chile; ChileFil: Husemann, Bernd. European Southern Observator; AlemaniaFil: Kehrig, C.. Instituto de Astrofísica de Andalucía; España. Consejo Superior de Investigaciones Científicas; EspañaFil: Marino, R. A.. Universidad Complutense de Madrid; España. ETH Zurich’s Institute for Astronomy; AlemaniaFil: Sánchez Blázquez, P.. Universidad Autónoma de Madrid; España. Pontificia Universidad Católica de Chile; ChileFil: López Cobá, C.. Universidad Nacional Autonoma de Mexico. Instituto de Astronomia; MéxicoFil: López Sánchez, Á. R.. Australian Astronomical Observatory; Australia. Macquarie University; AustraliaFil: Vílchez, J. M.. Instituto de Astrofísica de Andalucía; España. Consejo Superior de Investigaciones Científicas; Españ