Physiological effects of environmental acidification in the deep-sea urchin <i>Strongylocentrotus fragilis</i>

Anthropogenic CO₂ is now reaching depths over 1000 m in the Eastern Pacific, overlapping the Oxygen Minimum Zone (OMZ). Deep-sea animals are suspected to be especially sensitive to environmental acidification associated with global climate change. We have investigated the effects of elevated <i>p</i>CO₂ and variable O₂ on the deep-sea urchin <i>Strongylocentrotus fragilis</i>, a species whose range of 200–1200 m depth includes the OMZ and spans a <i>p</i>CO₂ range of approx. 600–1200 μatm (approx. pH 7.6 to 7.8). Individuals were evaluated during two exposure experiments (1-month and 4 month) at control and three levels of elevated <i>p</i>CO₂ at in situ O₂ levels of approx. 10% air saturation. A treatment of control <i>p</i>CO₂ at 100% air saturation was also included in experiment two. During the first experiment, perivisceral coelomic fluid (PCF) acid-base balance was investigated during a one-month exposure; results show <i>S. fragilis</i> has limited ability to compensate for the respiratory acidosis brought on by elevated <i>p</i>CO₂, due in part to low non-bicarbonate PCF buffering capacity. During the second experiment, individuals were separated into fed and fasted experimental groups, and longer-term effects of elevated <i>p</i>CO₂ and variable O₂ on righting time, feeding, growth, and gonadosomatic index (GSI) were investigated for both groups. Results suggest that the acidosis found during experiment one does not directly correlate with adverse effects during exposure to realistic future <i>p</i>CO₂ levels

Timing of detachment faulting in the Bullfrog Hills and Bare Mountain area, southwest Nevada: Inferences from 40Ar/39Ar, K-Ar, U-Pb and fission track thermochronology

Crustal extension in the Bullfrog Hills and Bare Mountain area of southwest Nevada is associated with movement along a regional detachment fault. Normal faulting in the upper plate and rapid cooling (denudation) of the lower plate were coeval with Miocene silicic volcanism and with west-northwest transport along the detachment fault. A west-northwest progression of tilting along upper plate normal faults is indicated by ages of the volcanic rocks in relation to angular unconformities. Near the breakaway, tilting in the upper plate occurred between 12.7 and 11.6 Ma, continued less strongly past 10.7 Ma, and was over by 8.2 Ma. Ten to 20 km west of the breakaway, tilting occurred between 10.7 and 10.33 Ma, continued less strongly after 10.33 Ma, and was over by 8.1 Ma. The cooling histories of the lower plate metamorphic rocks were determined by thermochronologic dating methods: K-Ar and Ar-40/(39)A on muscovite, biotite, and hornblende, Ar-40/(39)A on K-feldspar, U-Pb on apatite, zircon, and sphene, and fission track on apatite, zircon, and sphene. Lower plate rocks 10 km west of the breakaway cooled slowly from Early Cretaceous lower-amphibolite facies conditions through 350+/-50 degrees to 300+/-50 degrees C between 57 and 38 Ma, then cooled rapidly from 205+/-50 degrees to 120+/-5O degrees C between 12.6+/-1.6 and 11.1+/-1.9 Ma. Lower plate rocks 20 km west of the breakaway cooled slowly from Early Cretaceous upper-amphibolite facies conditions through 500+/-50 degrees C at 78-67 Ma, passed through 350+/-50 degrees to 300+/-50 degrees C between 16.3+/-0.4 and 10.5+/-0.3 Ma, then cooled rapidly from 285+/-50 degrees to 120+/-50 degrees C between 10.2 and 8.6 Ma. Upper plate tilting and rapid cooling (denudation) of the lower plate occurred simultaneously in the respective areas. The early slow-cooling part of the lower plate thermal histories was probably related to erosion at the Earth's surface, which stripped off about 9 km of material in 50 to 100 m.y. The results indicate an initial fault dip greater than or equal to 30 degrees and a 12 mm yr(-1) west-northwest migration of the locus of rapid tilting in the upper plate

Loading and haulage in quarries: criteria for the selection of excavator - dumper system

The optimisation of loading and haulage is one of the most important issues for the yield of quarrying activities. Many external factors may affect loading and haulage system selection: amongst them a very important role is played by local topography, stability conditions, size of the excavated material and capacity of the crusher. Of course, loading and haulage equipments affect one another and should be matched in order to get an efficient system, considering both production and economical aspects; selection criteria should be mainly based on: optimisation of loading system (sometimes working as excavation equipment too); optimisation of haulage system (in terms of both single equipment and fleet); optimisation of maintenance programs and organisation (in terms of availability of the system). In particular, the paper deals with the hydraulic excavator – dumper (or truck) system, focusing on the relations between the technical characteristics of the equipments. Many loading and haulage operations have been analysed in different Italian open cast mines and quarries, in order to identify the best working relations and to derive a simple procedure for a proper selection

Effect of the application of intermittent drying on Ilex paraguariensis quality and drying kinetics

The aim of this work was to study the effects of the application of tempering periods on the drying kinetics of yerba maté branches and on the resultant quality parameters of the finished product. Experiments were carried out in a convective pilot plant drier. Air temperature (60, 80 and 100 °C) and tempering time (0, 15 and 30 min) influenced the drying kinetics and the product quality (color parameters L and b, and the sugar and caffeine contents of an infusion prepared with the material). The influence of tempering time was higher at 60 °C than at the other temperatures. There were no differences between tempering times of 15 and 30 min. The Page model yielded a good fit to the experimental data, where the model parameter k varied with drying temperature.Fil: Ramallo, Laura Ana. Universidad Nacional de Misiones; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Lovera, Nancy Noelia. Universidad Nacional de Misiones; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; ArgentinaFil: Schmalko, Miguel E.. Universidad Nacional de Misiones; Argentin

Theoretical Criteria for Scattering Dark States in Nanostructured Particles

Nanostructures with multiple resonances can exhibit a suppressed or even completely eliminated scattering of light, called a scattering dark state. We describe this phenomenon with a general treatment of light scattering from a multiresonant nanostructure that is spherical or nonspherical but subwavelength in size. With multiple resonances in the same channel (i.e., same angular momentum and polarization), coherent interference always leads to scattering dark states in the low-absorption limit, regardless of the system details. The coupling between resonances is inevitable and can be interpreted as arising from far-field or near-field. This is a realization of coupled-resonator-induced transparency in the context of light scattering, which is related to but different from Fano resonances. Explicit examples are given to illustrate these concepts.Massachusetts Institute of Technology. Institute for Soldier Nanotechnologies (Contract W911NF-13-D-0001)National Science Foundation (U.S.). Materials Research Science and Engineering Centers (Program) (Grant DMR-0819762

Spatial Correlation Of Productive Component For Peach Palm Crop And Some Physical Attributes Of Eutrochrept Soil

Currently, Brazil sells around 300 million dollars per year of peach palms (Bactris gasipaes), wherein this country is responsible for being the largest worldwide producer, exporter and consumer. In crop year of 2014, productive components of peach palms were analyzed according to soil physical properties in Registro, SP, Brazil. The objectives were to evaluate the variability of the soil attributes and define a linear and spatial correlation between the crop productive components and the soil physical properties. Geostatistical grid was installed to collect data from soil and plant, with 54 sampling points in a total area of approximately 10,000 m2. With regard to linear point of view, stem diameter and palm height was explained by direct and exponential potential model, which was highly significant due to mechanical resistance to penetration.11316317