Selective Extraction Methods for Aluminium,Iron and Organic Carbon from Montane Volcanic Ash Soils

Montane volcanic ash soils contain disproportionate amounts of soil organic carbon and thereby play an often underestimated role in the global carbon cycle.Given the central role of Al and Fe in stabilizing organic matter in volcanic ash soils,we assessed various extraction methods of Al,Fe,and C fractions from montane volcanic ash soils in northern Ecuador,aiming at elucidating the role of Al and Fe in stabilizing soil organic matter(SOM).We found extractions with cold sodium hydroxide,ammonium oxalate/oxalic acid,sodium pyrophosphate,and sodium tetraborate to be particularly useful.Combination of these methods yielded information about the role of the mineral phase in stabilizing organic matter and the differences in type and degree of complexation of organic matter with Al and Fe in the various horizons and soil profiles.Sodium tetraborate extraction proved the only soft extraction method that yielded simultaneous information about the Al,Fe,and C fractions extracted.It also appeared to differentiate between SOM fractions of different stability.The fractions of copper chloride-and potassium chloride-extractable Al were useful in assessing the total reactive and toxic Al fractions,respectively.The classical subdivision of organic matter into humic acids,fulvic acids,and humin added little useful information.The use of fulvic acids as a proxy for mobile organic matter as done in several model-based approaches seems invalid in the soils studied.

Validation of the Wii Balance Board to assess static balance during dual-task activity in healthy subjects

Objective:Although dual-task paradigm is commonly used in rehabilitation there is,currently,a lack of information about quantitative balance assessment performed in dual-task conditions.The aim of this study is to validate the use of the Nintendo Wii Balance Board(WBB)to assess balance modifications induced by dual-task activity in healthy subjects.Material and methods:Seventy-five healthy participants(37±14 years old,173±8 cm,73
16 kg,35 women)participated in this study.Balance was recorded in control situation(baseline)and under two different cognitive tasks(verbal fluency and calculation).Each trial lasted for 60 s and were performed with eyes open and closed.Nine parameters were extracted based on center of pressure displacement based on a previously-validated method.ANOVA tests were used to compare the different conditions followed by Bonferroni’s corrections.Protocol was repeated one week after to assess the reproducibility.Results:Statistically significant differences were found comparing eyes open and closed situation.Concerning the influence of dual-tasks statistically significant decrease of the balance was observed for both eyes open and closed conditions(increase of the total sway and the speed of displacement).Concerning the reproducibility all parameters shows good to excellent ICC values for the different conditions.Conclusion:In this study,we demonstrated the validity of the WBB to detect the effect of the dual-task on balance in healthy subjects.Further studies are needed to determine if such a kind of evaluation can be used in clinics with subjects at risk of falling.

The use of cognitive mobile games to assess cognitive function of healthy subjects under various inspiratory loads

Objective:The aim of this work was to determine if scoring mechanisms embedded in cognitive mobile games(CMG)designed for cognitive training are sensitive enough to detect changes in cognitive function induced by various acute respiratory loads in healthy subjects.Material and methods:Thirty healthy subjects participated in this study(25±4 years old,13 women).A set of three brief CMG was used to assess cognitive function(Rush Back,Must Sort,True Color)in control situation and at four different inspiratory loads(through a mouthpiece without resistance and with 10,50 and 70%of the maximal inspiratory pressure).Results:Statistically significant decreases in CMG scores were observed in Rush Back(p=0.032)and True Color(p=0.002)when the subjects breathed through the mouthpiece without resistance compared to the control condition.A statistical difference was observed for Must Sort(p=0.003)between baseline and 10%of Inspiratory Threshold Load(ITL).Significant differences for the three games were observed between the baseline and 50%of ITL and between baseline and 70%of ITL.Conclusion:CMG designed for cognitive training are sensitive in detecting transitional changes in cognitive function induced by low,medium and high acute respiratory loads in healthy subjects.This offers interesting new possibilities for the assessment and long-term follow-up of patients suffering from chronic respiratory disease,since this type of assessment could easily be completed independently by patients in their own homes,and could be combined with rehabilitation exercises as an evaluative measure.