30 million years of Permian volcanism recorded in the Choiyoi igneous province (W Argentina) and their source for younger ash fall deposits in the Parana Basin: SHRIMP U-Pb zircon geochronology evidence

We present four SHRIMP U-Pb zircon ages for the Choiyoi igneous province from the San Rafael Block, central-western Argentina. Dated samples come from the Yacimiento Los Reyunos Formation (281.4 +/- 2.5 Ma) of the Cochico Group (Lower Choiyoi section: andesitic breccias, dacitic to rhyolitic ignimbrites and continental conglomerates). Agua de los Burros Formation (264.8 +/- 2.3 Ma and 264.5 +/- 3.0 Ma) and Cerro Carrizalito Formation (251.9 +/- 2.7 Ma Upper Choiyoi section: rhyolitic ignimbrites and pyroclastic flows) spanning the entire Permian succession of the Choiyoi igneous province. A single ziron from the El Imperial Formation, that is overlain unconformably by the Choiyoi succession, yielded an early Permian age (297.2 +/- 5.3 Ma). while the main detrital zircon population indicated an Ordovician age (453.7 +/- 8.1 Ma). The new data establishes a more precise Permian age (Artinskian-Lopingian) for the section studied spanning 30 Ma of volcanic activity. Volcanological observations for the Choiyoi succession support the occurrence of explosive eruptions of plinian to ultraplinian magnitudes, capable of injecting enormous volumes of tephra in the troposphere-stratosphere. The new SHRIMP ages indicate contemporaneity between the Choyoi succession and the upper part of the Parana Basin late Paleozoic section, from the Irad up to the Rio do Rasto formations, encompassing about 24 Ma. Geochemical data show a general congruence in compositional and tectonic settings between the volcanics and Parana Basin Permian ash fall derived layers of bentonites. Thickness and granulometry of ash fall layers broadly fit into the depletion curve versus distance from the remote source vent of ultraplinian eruptions. Thus, we consider that the Choiyoi igneous province was the source of ash fall deposits in the upper Permian section of the Parana Basin. Data presented here allow a more consistent correlation between tectono-volcanic Permian events along the paleo-Pacific margin of southwestern Gondwana and the geological evolution of neighboring Paleozoic foreland basins in South America and Africa. (C) 2010 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.

Well-preserved Late Paleoproterozoic volcanic centers in the Sao Felix do Xingu region, Amazonian Craton, Brazil

The Amazonian craton in the Sao Felix do Xingu city, southeast region of the Para state, north of Brazil, hosts exceptionally well-preserved Paleoproterozoic bimodal magmatic units grouped in the Sobreiro and Santa Rosa formations. These formations are correlated to the Uatuma magmatic event, which is largely distributed in the Amazonian craton occupying more than 1,500,000 km(2). Geological mapping and petrographical observations reveal distinct spectra of volcanic facies in both formations. The basal calc-alkaline Sobreiro Formation is composed mainly of andesitic and dacitic lava flows and associated volcaniclastic facies of autoclastic origin, with subordinate pyroclastic flow deposits. This formation shows inferred eruption style that is similar to those in Flood Basalt Provinces, with rare scutulum-type lava shields. The upper A-type Santa Rosa Formation was generated by multicyclic explosive and effusive episodes predominantly associated with large fissures and is materialized by voluminous ignimbrites with subordinated ash-fall tuff, crystal tuff, lapilli-tuff, co-ignimbritic breccias, rhyolitic dikes and domes, and associated granitic porphyries and equigranular granitic intrusions. Ignimbrite and rhyolite dikes reveal conspicuous vertical flow pattern pointing to a fissure-controlled eruption, similar to Sierra Madre Occidental ignimbrite province. The proposed evolutionary model for the Sao Felix do Xingu units differs from those of other occurrences related to the Uatuma magmatic event in the Amazonian craton, characterized by predominance of A-type volcanism and contemporaneous granites. (C) 2010 Elsevier B.V. All rights reserved.

Free-fall in a uniform gravitational field in noncommutative quantum mechanics

We study the free-fall of a quantum particle in the context of noncommutative quantum mechanics (NCQM). Assuming noncommutativity of the canonical type between the coordinates of a two-dimensional configuration space, we consider a neutral particle trapped in a gravitational well and exactly solve the energy eigenvalue problem. By resorting to experimental data from the GRANIT experiment, in which the first energy levels of freely falling quantum ultracold neutrons were determined, we impose an upper-bound on the noncommutativity parameter. We also investigate the time of flight of a quantum particle moving in a uniform gravitational field in NCQM. This is related to the weak equivalence principle. As we consider stationary, energy eigenstates, i.e., delocalized states, the time of flight must be measured by a quantum clock, suitably coupled to the particle. By considering the clock as a small perturbation, we solve the (stationary) scattering problem associated and show that the time of flight is equal to the classical result, when the measurement is made far from the turning point. This result is interpreted as an extension of the equivalence principle to the realm of NCQM. (C) 2010 American Institute of Physics. [doi:10.1063/1.3466812]

Peak torque and rate of torque development in elderly with and without fall history

Background Falls are one of the greatest concerns among the elderly A number of studies have described peak torque as one of the best fall-related predictor. No studies have comprehensively focused on the rate of torque development of the lower limb muscles among elderly fallers. Then, the aim of this study was to determine the relationship between muscle peak torque and rate of torque development of the lower limb joints in elderly with and without fall history It was also aimed to determine whether these parameters of muscle performance (i e, peak torque and rate of torque development) are related to the number of falls. Methods: Thirty-one women volunteered to participate in the study and were assigned in one of the groups according to the number of falls over the 12 months that preceded the present Then, participants with no fall history (Cl; n = 13; 67.6[7.5] years-old), one fall (GII; n = 8, 66 0[4 91 years-old) and two or more falls (GIII, n = 10; 67.8[8.8] years-old) performed a number of lower limb maximal isometric voluntary contractions from which peak torque and rate of torque development were quantified Findings. Primary outcomes indicated no peak torque differences between experimental groups in any lower limb joint. The rate of torque development of the knee flexor muscles observed in the non-fallers (Cl) was greater than that observed in the fallers (P < 0.05) and had a significant relationship with the number of falls (P < 0 05) Interpretation. The greater knee flexor muscles` rate of torque development found in the non-fallers in comparison to the fallers indicated that the ability of the elderly to rapidly reorganise the arrangement of the lower limb may play a significant role in allowing the elderly to recover balance after a trip. Thus, training stimulus aimed to improve the rate of torque development may be more beneficial to prevent falls among the elderly than other training stimulus, which are not specifically designed to improve the ability to rapidly produce large amounts of torque (C) 2010 Published by Elsevier Ltd

Strength training improves fall-related gait kinematics in the elderly: a randomized controlled trial

Background: Falls are one of the greatest concerns among the elderly. Among a number of strategies proposed to reduce the risk of falls, improving muscle strength has been applied as a successful preventive strategy. Although it has been suggested as a relevant strategy, no studies have analyzed how muscle strength improvements affect the gait pattern. The aim of this study was to determine the effects of a lower limb strength training program on gait kinematics parameters associated with the risk of falls in elderly women. Methods: Twenty seven elderly women were assigned in a balance and randomized order into an experimental (n = 14: age = 61.1 (4.3) years, BMI = 26.4 (2.8) kg m(-2)) and a control (n = 13; age = 61.6 (6.6) years; BMI = 25.9 (3.0) kg m(-2)) group. The EG performed lower limb strength training during 12 weeks (3 days per week), being training load increased weekly. Findings: Primary outcomes were gait kinematics parameters and maximum voluntary isometric contractions at pre- and post-training period. Secondary outcomes were training load improvement weekly and one repetition maximum every two weeks. The I maximal repetition increment ranged from 32% to 97% and was the best predictor of changes in gait parameters (spatial, temporal and angular variables) after training for the experimental group. Z-score analysis revealed that the strength training was effective in reversing age-related changes in gait speed, stride length, cadence and toe clearance, approaching the elderly to reference values for healthy young women. Interpretation: Lower limb strength training improves fall-related gait kinematic parameters. Thus, strength training programs should be recommended to the elderly women in order to change their gait pattern towards young adults. (C) 2009 Elsevier Ltd. All rights reserved.

Surface modification of bovine bone ash prepared by milling and acid washing process

Bovine bone ash is the main raw material for fabrication of bone china, a special kind of porcelain that has visual and mechanical advantages when compared to usual porcelains. The properties of bone china are highly dependent on the characteristics of the bone ash. However, despite a relatively common product, the science behind formulations and accepted fabrication procedures for bone china is not completely understood and deserves attention for future processing optimizations. In this paper, the influence of the preparation steps (firing, milling, and washing of the bones) on the physicochemical properties of bone ash particles was investigated. Bone powders heat-treated at temperatures varying from 700 to 1000 degrees C were washed and milled. The obtained materials were analyzed in terms of particle size distribution, chemical composition, density, specific surface area, FTIR spectroscopy, dynamic electrophoretic mobility, crystalline phases and scanning electron microscopy. The results indicated that bone ash does not significantly change in terms of chemistry and physical features at calcination temperatures above 700 degrees C. After washing in special conditions, one could only observe hydroxyapatite in the diffraction pattern. By FTIR it was observed that carbonate seems to be mainly concentrated on the surface of the powders. Since this compound can influence in the dispersion stability, and consequently in the quality of the final bone china product, and considering optimal washing parameters based on the dynamic electrophoretic mobility results, we describe a procedure for surface cleaning. (c) 2009 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

Storage as a tool to improve wood fuel quality

This work analysed the influence of storage in the quality of forest biomass for energy generation in the region of Lages, Brazil. Logs of Pinus taeda L. and Eucalyptus dunnii Maiden were harvested and piled during the four different seasons: spring, summer, fall and winter. The analyses were performed immediately after harvesting (without being stored), after two, four and six months of storage. The evaluated properties were: moisture content, gross and net calorific value, ash content and solubility in cold water, hot water and sodium hydroxide. The species composition, storage span, harvesting season and storage season influenced the forest biomass characteristics. In general, eucalyptus presented better results than pine, losing moisture faster, having less alteration in the chemical composition and producing greater energetic gain over storage time. For both species, the ideal storage time was four months. Furthermore, spring and summer were the best harvesting seasons. Thus, if the forest biomass is harvested at the end of winter or beginning of spring with subsequent storage during the summer, this biomass will have the best performance for energy production. (C) 2011 Elsevier Ltd. All rights reserved.

Phylogeography of Chelonus insularis (Hymenoptera: Braconidae) and Campoletis sonorensis (Hymenoptera: Ichneumonidae), Two Primary Neotropical Parasitoids of the Fall Armyworm (Lepidoptera: Noctuidae)

In a previous study, we observed no spatial genetic structure in Mexican populations of the parasitoids Chelonus insularis Cresson (Hymenoptera: Braconidae) and Campoletis sonorensis Cameron (Hymenoptera: Ichneumonidae) by using microsatellite markers In the current study, we Investigated whether for these important parasitoids of the fall armyworm (Lepidoptera: Noctuidae) there is any genetic structure at a larger scale Insects of both species were collected across the American continent and their phylogeography was Investigated using both nuclear and mitochondria] markers Our results suggest an ancient north-south migration of C insularis, whereas no clear pattern] could be determined for C sonorensis. Nonetheless, the resulting topology indicated the existence of a cryptic taxon within this later species. a few Canadian specimens determined as C. sonorensis branch outside a clack composed of the Argentinean Chelonus grioti Blanchard, the Brazilian Chelonus flavicincta Ashmead, and the rest of the C sonorensis individuals The individuals revealing the cryptic taxon were collected from Thichoplusia in (Hubner) (Lepidoptera. Noctuidae) on tomato (Lycopersicon spp) and may represent a biotype that has adapted to the early season phenology of its host. Overall, the loosely defined spatial genetic structure previously shown at a local fine scale also was found at the larger scale, for both species Dispersal of these insects may be partly driven by wind as suggested by genetic similarities between Individuals coming from very distant locations.

Chronic nasal instillation of residual-oil fly ash (ROFA) induces brain lipid peroxidation and behavioral changes in rats

Several epidemiological studies have linked particulate matter exposure to numerous adverse health effects on the respiratory, cardiovascular, and reproductive systems (Braga et al., 1999; Zanobetti et al., 2000; Anderson et al., 2001; Farhat et al., 2005). More recently, ambient levels of black carbon were associated to impaired cognitive function in children (Suglia et al., 2008), suggesting that the central nervous system (CNS) may be a target of air pollutants. The present study was conducted to (a) determine whether chronic residual oil fly ash (ROFA) exposure promotes behavioral changes and lipid peroxidation in rat brain areas, and (b) determine whether N-acetylcysteine (NAC), a general antioxidant, prevents these effects. Forty-five-day-old male Wistar rats were exposed or not to ROFA by intranasal instillation and were treated or not with NAC (150 mg/kg) ip for 30 days. One day later, rats were submitted to the open field test to evaluate the motor/exploratory activities and emotionality followed by decapitation. Striatum and cerebellum were dissected to determine lipid peroxidation by the accumulation of thiobarbituric acid-reactive substances (TBARS). ROFA instillation induced an increase in lipid peroxidation level in striatum (p = .033) and cerebellum (p = .030), as compared with the control group. NAC treatment blocked these changes. ROFA promoted a decrease in the frequency of peripheral walking (p = .006) and a decrease in exploration (p = .001), which were not blocked by N-acetylcysteine. The present study provides evidence that toxic particles, administered by the respiratory route, induce oxidative stress in structures of the central nervous system, as well as behavioral alterations. The administration of NAC reduces lipid peroxidation at the striatum and cerebellum levels, but does not influence behavioral disturbances.

Hippocampus lipid peroxidation induced by residual oil fly ash intranasal instillation versus habituation to the open field

Epidemiological studies have demonstrated the adverse effects of particulate matter (PM) inhalation on the respiratory and cardiovascular systems. It has been reported that air pollution may affect the central nervous system and decrease cognitive function. In rats, residual oil fly ash (ROFA) instillation causes decreased motor activity and increased lipid peroxidation in the striatum and the cerebellum. Our objective was to determine whether chronic instillation of particles induces changes in learning and memory in rats and whether oxidants in the hippocampus may contribute to these adverse effects. Forty-five-day-old male Wistar rats were exposed to ROFA by intranasal instillation and were treated with N-acetylcysteine (NAC) at 150 mg/kg i.p. for 30 days. Control groups were exposed to ROFA, NAC, or neither. On days 1, 8, and 30 of the protocol, rats were submitted to the open field test to evaluate habituation. After the last open field session, the rats were killed by decapitation. The hippocampus was used to determine lipid peroxidation (LP) by the thiobarbituric acid-reactive substances test. ROFA instillation induced an increase in LP in the hippocampus compared to all treatment groups (p = .012). NAC treatment blocked these changes. All of the treatment groups presented a decrease in the frequency of peripheral walking (p = .001), rearing (p = .001), and exploration (p = .001) over time. Our study demonstrates that exposure to particles for 30 days and/or NAC treatment do not modify habituation to an open field, a simple form of learning and memory in rats, and that oxidative damage induced by ROFA does not modulate these processes.

Effects of Residual Oil Fly Ash (ROFA) in Mice with Chronic Allergic Pulmonary Inflammation

transition metals, which are involved in the pathological effects of PM. The objective of this study was to investigate the effects of intranasal administration of ROFA on pulmonary inflammation, pulmonary responsiveness, and excess mucus production in a mouse model of chronic pulmonary allergic inflammation. BALB/c mice received intraperitoneal injections of ovalbumin (OVA) solution (days 1 and 14). OVA challenges were performed on days 22, 24, 26, and 28. After the challenge, mice were intranasally instilled with ROFA. After forty-eight hours, pulmonary responsiveness was performed. Mice were sacrificed, and lungs were removed for morphometric analysis. OVA-exposed mice presented eosinophilia in the bronchovascular space (p < .001), increased pulmonary responsiveness (p < .001), and epithelial remodeling (p = .003). ROFA instillation increased pulmonary responsiveness (p = .004) and decreased the area of ciliated cells in the airway epithelium (p = .006). The combined ROFA instillation and OVA exposure induced a further increase in values of pulmonary responsiveness (p = .043) and a decrease in the number of ciliated cells in the airway epithelium (p = .017). PM exposure results in pulmonary effects that are more intense in mice with chronic allergic pulmonary inflammation.

Pozzolanic behavior of bamboo leaf ash: Characterization and determination of the kinetic parameters

The paper presents a characterization and study of the pozzolanic behavior between calcium hydroxide (CH) and bamboo leaf ash (BLAsh), which was obtained by calcining bamboo leaves at 600 degrees C for 2 h in a laboratory electric furnace. To evaluate the pozzolanic behavior the conductometric method was used, which is based on the measurement of the electrical conductivity in a BLAsh/CH solution with the reaction time. Later, the kinetic parameters are quantified by applying a kinetic-diffusive model. The kinetic parameters that characterize the process (in particular, the reaction rate constant and free energy of activation) were determined with relative accuracy in the fitting process of the model. The pozzolanic activity is quantitatively evaluated according to the values obtained of the kinetic parameters. Other experimental techniques, such as X-ray diffraction (XRD) and scanning electron microscopy (SEM), were also employed. The results show that this kind of ash is formed by silica with a completely amorphous nature and a high pozzolanic activity. The correlation between the values of free energy of activation (Delta G(#)) and the reaction rate constants (K) are in correspondence with the theoretical studies about the rate processes reported in the literature. (C) 2010 Elsevier Ltd. All rights reserved.

A study of the chemical and physical properties of cashew nut shell ash for use in cement materials.

A study of the chemical and physical properties of cashew nut shell ash for use in cement materials. Ash occupies a prominent place among agro-industrial wastes, as it is derived from energy generation processes. Several types of ash have pozzolanic reactivity, and might be used as replacement material for cement, resulting in less energy waste and lower cost. This work aimed to investigate the physical and chemical properties of the cashew nut shell ash (CNSA), by performing the following measurement tests: chemical analysis, bulk density, specific mass, leaching and solubilization process, X-ray diffraction (XrD), specific surface area (BET) and pozzolanicity analysis with cement and lime. The results indicate a low reactivity of CNSA and the presence of heavy metals, alkalis and phenol.

Study of the pozzolanic reaction kinetics in sugar cane bagasse-clay ash/calcium hydroxide system: kinetic parameters and pozzolanic activity

This paper presents a study of the pozzolanic reaction kinetics between calcium hydroxide and a mixture of sugar cane bagasse with 20 and 30% of clay, burned at 800 and 1000 degrees C (SCBCA) by electrical conductivity measurements. A kinetic-diffusive model produced in previous studies by some of the authors was used. The model was fitted to the experimental data, which allowed the computation of the kinetic parameters of the pozzolanic reaction (reaction rate constant and free energy of activation) that rigorously characterised the pozzolanic activity of the materials. The results show that SCBCA demonstrated reactivity and good pozzolanic qualities in the range 800-1000 degrees C.