Galaxy and Mass Assembly (GAMA): merging galaxies and their properties

We derive the close pair fractions and volume merger rates for galaxies in the Galaxy and Mass Assembly (GAMA) survey with −23 < Mr < −17 (ΩM = 0.27, ΩΛ = 0.73, H0 = 100 km s−1 Mpc−1) at 0.01 < z < 0.22 (look-back time of <2 Gyr). The merger fraction is approximately 1.5 per cent Gyr−1 at all luminosities (assuming 50 per cent of pairs merge) and the volume merger rate is ≈3.5 × 10−4 Mpc−3 Gyr−1. We examine how the merger rate varies by luminosity and morphology. Dry mergers (between red/spheroidal galaxies) are found to be uncommon and to decrease with decreasing luminosity. Fainter mergers are wet, between blue/discy galaxies. Damp mergers (one of each type) follow the average of dry and wet mergers. In the brighter luminosity bin (−23 < Mr < −20), the merger rate evolution is flat, irrespective of colour or morphology, out to z ∼ 0.2. The makeup of the merging population does not appear to change over this redshift range. Galaxy growth by major mergers appears comparatively unimportant and dry mergers are unlikely to be significant in the buildup of the red sequence over the past 2 Gyr. We compare the colour, morphology, environmental density and degree of activity (BPT class, Baldwin, Phillips & Terlevich) of galaxies in pairs to those of more isolated objects in the same volume. Galaxies in close pairs tend to be both redder and slightly more spheroid dominated than the comparison sample. We suggest that this may be due to ‘harassment’ in multiple previous passes prior to the current close interaction. Galaxy pairs do not appear to prefer significantly denser environments. There is no evidence of an enhancement in the AGN fraction in pairs, compared to other galaxies in the same volume

Control Structure Design Using Global Sensitivity Analysis for Mineral Processes under Uncertainties

Multiple-input and multiple-output (MIMO) systems can be found in many industrial processes, including mining processes. In practice, these systems are difficult to control due to the interactions of their input variables and the inherent uncertainty of industrial processes. Depending on the interactions in the MIMO process, different control strategies can be implemented to achieve the desired performance. Among these strategies is the use of a decentralized structure that considers several subsystems and for which a SISO controller can be designed. In this study, a methodology based on global sensitivity analysis (GSA) to design decentralized control structures for industrial processes under uncertainty is presented. GSA has not yet been applied for this purpose in process control; it allows us to understand the dynamic behavior of systems under uncertainty in a broad value range, unlike approaches proposed in the literature. The proposed GSA is based on the Sobol method, which provides sensitivity indices used as interaction measures to establish the input&ndash;output pairing for MIMO systems. Two case studies based on a semi-autogenous grinding (SAG) mill and a solvent extraction (SX) plant are presented to demonstrate the applicability of the proposed methodology. The results indicate that the methodology allows the design of 2 &times; 2 and 3 &times; 3 decentralized control structures for the SAG mill and SX plant, respectively, which exhibit good performance compared to MPC. For example, for the SAG mill, the determined pairings were fresh ore flux/fraction of mill filling and power consumption/percentage of critical speed

Pyrite depression by dextrin in flotation with xanthates. Adsorption and floatability studies

Depression of pyrite by dextrin in flotation with xanthates has been studied. The adsorption of dextrin and xanthates at the pyrite/aqueous solution interface has been investigated through electrokinetics, Raman spectroscopy and batch adsorption studies using oxidized pyrite. Microflotation studies were undertaken to evaluate the pyrite depression with dextrin using ethyl and propyl xanthates as the collector. The surface density of ferric hydroxide on pyrite depended on pH and was highest about the iep (pH 7.5) of the oxidized pyrite. Dextrin adsorption was directly related to the surface density of ferric hydroxide and took place through two steps suggesting two adsorption mechanisms on ferric hydroxide. Xanthate adsorption as dixanthogen occurred along with ferric hydroxide dissolution causing partial dextrin desorption from the pyrite surface; consequently, co-adsorption of xanthate and dextrin occurred on the surface. Depression of pyrite flotation with xanthate was determined by the oxidation level of the pyrite surface. Floatability of pyrite with xanthate was highly impaired by dextrin at pH 8 only when the surface density of ferric hydroxide on the pyrite surface was very high

Acid Rock Drainage and Rock Weathering in Antarctica: Important Sources for Iron Cycling in the Southern Ocean

Here we describe biogeochemical processes that lead to the generation of acid rock drainage (ARD) and rock weathering on the Antarctic landmass and describe why they are important sources of iron into the Antarctic Ocean. During three expeditions, 2009–2011, we examined three sites on the South Shetland Islands in Antarctica. Two of them displayed intensive sulfide mineralization and generated acidic (pH 3.2–4.5), iron-rich drainage waters (up to 1.78 mM Fe), which infiltrated as groundwater (as Fe²⁺) and as superficial runoff (as Fe³⁺) into the sea, the latter with the formation of schwertmannite in the sea-ice. The formation of ARD in the Antarctic was catalyzed by acid mine drainage microorganisms found in cold climates, including <i>Acidithiobacillus ferrivorans</i> and <i>Thiobacillus plumbophilus</i>. The dissolved iron (DFe) flux from rock weathering (nonmineralized control site) was calculated to be 0.45 × 10⁹ g DFe yr^–1 for the nowadays 5468 km of ice-free Antarctic rock coastline which is of the same order of magnitude as glacial or aeolian input to the Southern Ocean. Additionally, the two ARD sites alone liberate 0.026 and 0.057 × 10⁹ g DFe yr^–1 as point sources to the sea. The increased iron input correlates with increased phytoplankton production close to the source. This might even be enhanced in the future by a global warming scenario, and could be a process counterbalancing global warming

Variation in the number of metamers of rectus abdominis muscle. A high definition lipoesculture guide Variaciones en el número de metámeros del músculo recto abdominal. Una guía para la lipoescultura de alta definición

© 2018 Sociedad Espanola de Cirugia Plastica Reparadora y Estetica (SECPRE). All rights reserved. Background and Objective. Rectus abdominis muscle usually have 3 tendinous intersections. The aims of high definition abdominal liposculpture is to delineate the musculature. One of its difficulties is to determine by the surface anatomy the number of metamers presents. The aim of this study is to describe the variations in the number of metamers of the rectus abdominis muscle in the Chilean population and determine if there is a pattern that helps to the surgical mark of the abdominis metamers. Methods. Randomized sample of 200 patients who met inclusion criteria: &gt;18 years of age and under 65 years, tomographic study of the abdomen and pelvis with coronal sequence, performed at the Clinical Hospital of the University of Chile between January and May 2017; and exclusion: pathology of the abdominal wall, previous abdominal surgery or inadequate imaging study. Sex, number of tendinous inte

Contrasting Physiological Responses of Two Populations of the Razor Clam Tagelus dombeii with Different Histories of Exposure to Paralytic Shellfish Poisoning (PSP)

This study describes the physiological performance of two populations of the razor clam Tagelus dombeii from two geographic areas with different histories of exposure to paralytic shellfish poisoning (PSP) linked to the toxic dinoflagellate Alexandrium catenella. Clams from Melinka-Aysen, which are frequently exposed to PSP, were not affected by the presence of toxins in the diet. However, clams from Corral-Valdivia, which have never been exposed to PSP, exhibited significantly reduced filtration activity and absorption, affecting the energy allocated to scope for growth (SFG). Ammonia excretion and oxygen uptake were not affected significantly by the presence of A. catenella in the diet. Measurements of energy acquisition and expenditure were performed during a 12-day intoxication period. According to three-way repeated measure ANOVAs, the origin of the clams had a highly significant effect on all physiological variables, and the interaction between diet and origin was significant for the clearance and absorption rates and for the scope for growth. The scope for growth index showed similar positive values for both the toxic and non-toxic individuals from the Melinka-Aysen population. However, it was significantly reduced in individuals from Corral-Valdivia when exposed to the diet containing A. catenella. The absence of differences between the physiological response of the toxic and non-toxic clams from Melinka-Aysen may be related to the frequent presence of A. catenella in the environment, indicating that this bivalve does not suffer negative consequences from PSP. By contrast, A. catenella has a negative effect on the physiological performance, primarily on the energy gained from the environment, on T. dombeii from Corral-Valdivia. This study supports the hypothesis that the history of PSP exposure plays an important role in the physiological performance and fitness of filter feeding bivalves

Variation in the number of metamers of rectus abdominis muscle. A high definition lipoesculture guide Variaciones en el número de metámeros del músculo recto abdominal. Una guía para la lipoescultura de alta definición

© 2018 Sociedad Espanola de Cirugia Plastica Reparadora y Estetica (SECPRE). All rights reserved. Background and Objective. Rectus abdominis muscle usually have 3 tendinous intersections. The aims of high definition abdominal liposculpture is to delineate the musculature. One of its difficulties is to determine by the surface anatomy the number of metamers presents. The aim of this study is to describe the variations in the number of metamers of the rectus abdominis muscle in the Chilean population and determine if there is a pattern that helps to the surgical mark of the abdominis metamers. Methods. Randomized sample of 200 patients who met inclusion criteria: &gt;18 years of age and under 65 years, tomographic study of the abdomen and pelvis with coronal sequence, performed at the Clinical Hospital of the University of Chile between January and May 2017; and exclusion: pathology of the abdominal wall, previous abdominal surgery or inadequate imaging study. Sex, number of tendinous inte

Variaciones en el número de metámeros del músculo recto abdominal. Una guía para la lipoescultura de alta definición

Resumen Introducción y Objetivo: El recto abdominal es un músculo que consta, generalmente, de 3 inserciones tendinosas transversas. La lipoescultura de alta definición apunta a delinear la musculatura abdominal, sin embargo, una de sus dificultades es determinar mediante la anatomía de superficie el número de metámeros presentes. Nos planteamos describir las variaciones en el número de metámeros del músculo recto del abdomen en la población chilena mediante análisis de tomografía computarizada de abdomen y pelvis, así como determinar si existe un patrón para la marcación quirúrgica de los metámeros. Material y Métodos: Empleamos una muestra aleatoria de 200 pacientes que cumplían los criterios de inclusión: mayores de 18 años y menores de 65 años, estudio de tomografía computarizada de abdomen y pelvis con secuencia coronal realizado en el Hospital Clínico de la Universidad de Chile entre enero y mayo del 2017; y de exclusión: patología de la pared abdominal, cirugía abdominal previa, estudio imagenológico inadecuado. Describimos el sexo, número de inserciones tendinosas supra e infraumbilicales, ángulo costal corto, ángulo costal completo, diámetro xifo-umbilical y umbílico-púbico. Analizamos los datos con STATA® v13, considerando un valor estadísticamente significativo de p<0.05 e intervalos de confianza de 95%. Resultados: Del total de paciente, 100 (50%) de los pacientes fueron mujeres. La media de edad fue de 40,9 ± 12.1 años, y 154 pacientes (77%) tenían 3 metámeros. No evidenciamos diferencias significativas entre ambos sexos (p=0.393). Ni en el análisis de la distancia xifo-umbilical (p=0.185) ni de la umbílico-púbica (p=0.327) entre sexos respectivamente. El número de metámeros se encuentra en relación inversa al tamaño de los mismos. La angulación del reborde costal en relación al xifoides es significativamente menor en mujeres (69.4 ± 15.2 frente a 80.2 ± 14.2). Conclusiones: La anatomía más frecuente del músculo recto del abdomen en la población chilena corresponde a 3 metámeros supraumbilicales por cada recto abdominal. Cuanto menor sea la relación entre la distancia xifo-umbilical / distancia xifo-púbica, menor cantidad de metámeros tiene el músculo recto. No fue posible predecir en forma precisa el número de metámeros mediante otra medida antropométrica

Tear sample collection using cellulose acetate absorbent filters

PURPOSE: To assess the use of cellulose acetate filter rods as a technique for tear collection. METHOD: The cellulose acetate rod (CR) was compared with the 'standard' glass capillary tube (CT), in a series of experiments, to assess: sample collection by collected volume size; the effect of tear stimulation on total tear protein concentration and major tear protein concentrations; and technique invasiveness. RESULTS: No difference was found in concentrations for total protein, IgA (secretory immunoglobulin A), lactoferrin and lysozyme (p > 0.05) with no clinically significant increase in serum albumin to show serum leakage. Sample volume was higher for CR (p < 0.005) and sample volume increased for stimulated collection with CR (p = 0.001). Dilution effect of a stimulated sample size was reliably shown only with CR (r = -0.66, p = 0.011). Using bovine albumin standard with CR and CT, a smaller sample volume (p < 0.001) and a higher protein concentration (p < 0.001) were extracted with CR. CONCLUSION: The cellulose rod offers a suitable alternative to the glass CT. It is able to quickly absorb a sample, allowing use for a wide range of sample sizes, while being minimally invasive