New insights into the characteristics and dynamics of rhyolite long-lasting volcanic eruptions

Recent rhyolite eruptions on Earth have demonstrated their capacity to produce a multitude of hazards, including ash formation lasting months and impacting the large reaches of the southern hemisphere. The eruptions of Chaitén volcano in 2008 and Cordón Caulle in 2011, both in Chile, ended a period of almost 100 years without major silicic events. Since then, significant effort has been invested in the characterization of these long-lasting eruptions and their products. However, still many aspects about the dynamics and underlying mechanisms driving rhyolite eruptions remain unravelled. These rhyolite eruptions provided not only vast amounts of fresh volcanic glass and hence a physicochemical window into the eruption dynamics, but also key temporal aspects of explosive and effusive phases. Here, almost 500 glass shards from the different eruptive phases of 2008 Chaitén eruption were analysed for their H2O content. Results show that eruptive products preserve a wide range of residual H2O contents (0.1 to 3.4 wt.%), with an overall trend of H2O depletion from explosive to effusive. In addition, the presence of “H2O content windows” within stratigraphic horizons of the pyroclastic sequences, defined by upper and lower H2O content values, was detected. Interestingly, these windows shift with stratigraphic position and demarcate clear H2O gaps with respect to effusive obsidians. Guided by the H2O distributions observed in the different deposits, 94 heating experiments were carried out at 0.1 MPa, temperatures between 740–1030°C on cylindrical obsidian cores (4X10mm) with water content between 0.13–1.4 wt.%. Results reveal different degassing behaviors and deformation timescales of the glassy material as a function of the initial H2O content of the sample. The most striking finding is the occurrence of explosive fragmentation at T >874°C in samples with H2O = 1.4 wt.%. This provides the first observations on explosive fragmentation due to experimental vesiculation of hydrous rhyolite melt and demonstrate that starting H2O concentration and temperature control eruptive behaviour. A comparison with a separate set of high-P experiments performed in a fragmentation bomb —which simulates fragmentation by rapid decompression— suggest that both fragmentation mechanisms might have operated during different stages of 2008 Chaitén eruption. Finally, the characteristics and impacts of ash-related hazards associated with these long-lasting events were explored. In addition to the impact of primary tephra fallout, a vast area of the Argentinian Patagonia was also significantly affected by wind-remobilization of ash. Results of this study show the primary importance of wind, rainfall and ash availability in controlling the occurrence and persistence of these events. Regarding the impacts, although in the short-term they were highly negative, the environment and the community start showing signs of recovery after five years.Eruptionen rhyolitischer Vulkane innerhalb der letzten Jahre haben, mit beispielsweise monatelanger Ascheproduktion und ihrer weitreichenden Auswirkungen auf die südlichen Hemisphäre, eindrucksvoll die Gefahrenbandbreite unter Beweis gestellt, die von solchen Vulkansystemen ausgehen kann. In 2008 und 2011 brachen in Chile relativ unvermittelt die Vulkane Chaitén und Cordón Caulle aus, beide nach einer fast hundertjährigen Pause größerer Vulkanaktivität. Seither werden große Anstrengungen unternommen, diese lang-anhaltenden rhyolitischen Eruptionen und ihre Produkte näher zu untersuchen. Nichtdestotrotz, verbleiben viele Aspekte der Ausbruchsdynamik und den zugrundeliegenden Mechanismen weiterhin im Dunkeln. Derartige rhyolitische Eruptionen produzieren einerseits große Mengen vulkanisches Glas—Bimsfragmente und Obsidianglas—welches physikochemische Einblicke in die Eruptionsdynamik ermöglicht, und erlauben andererseits eine genaue zeitliche Einordnung der unterschiedlichen Phasen effusiver und explosiver Aktivität und deren Ablagerungen. In der vorliegenden Studie wurden über 500 rhyolitische Glasfragmente aus Ablagerungen verschiedener Ausbruchsphasen des Chaitén Vulkans in 2008 auf ihren residualen Wassergehalt hin untersucht. Dieser erwies sich über alle Eruptionsprodukte hinweg als sehr variabel mit Konzentrationen zwischen 0.1 bis 3.4 wt.%, wobei sich ein genereller Trend von niedrigen Wassergenalten in effusiven Produkten hin zu hohen Wassergehalten in den explosiven Ablagerungen zeigte. Darüberhinaus ließ sich innerhalb der einzelnen stratigraphischen Horizonte der pyroklastischen Ablagerung ein „Wasserkonzentrations-Fenster“ erkennen, definiert über minimalen und maximalen Wassergehalte der einzelnen Ablagerungshorizonte, welches sich in Breite und Absolutwerte der Wasserkonzentration innerhalb der vertikalen Stratigraphie verändert. Interessanter Weise grenzt dieses Fenster scharf die Wassergehalte der explosiven Produkte von den niedrigeren der effusiven Obsidiangläser ab. An systematisch ausgewählten Gläsern dieser Ablagerung mit Wassergehalten von 0.13–1.4 wt.% wurden 94 Aufheizexperimente unter Atmosphärendruck und 740–1030°C durchgeführt. In Abhängigkeit des initialen Wassergehaltes zeigten die Proben unterschiedliches Entgasungsverhalten und Deformationszeitskalen des ursprünglich glasigen Materials. Als wichtigste Erkenntnis ergibt sich, dass Gläser mit ausreichend hohem Wassergehalt (≥1.4 wt.%) bei hohen Temperaturen (>874°C) schlagartig fragmentieren. Dies ist der erstmalige Nachweis explosiver Fragmentation durch Vesikulierung einer wässrigen rhyolitischen Schmelze unter experimentellen Bedingungen. Hier wird deutlich, dass initialer Wassergehalt sowie Temperatur maßgeblich das Ausbruchsverhalten beeinflussen. Ein Vergleich mit einem separaten Set an Hochdruckexperimenten in einer Fragmentationsbombe, welche Fragmentation durch rasche Druckentlastung simuliert, legt nahe, dass beide Fragmentationsmechanismen im Laufe der verschiedenen Ausbruchsstadien des Chaitén in 2008 zum Tragen kamen. Zuletzt werden die Gefahren durch Vulkanasche, die mit solch lang-anhaltenden Eruptionen assoziiert sind, charakterisiert und deren Auswirkungen am Beispiel Patagoniens, Argentinien sondiert. Zusätzlich zu den unmittelbaren Auswirkungen durch primären Tephraregen, zeigte sich, dass weite Gebiete Patagoniens auch stark durch äolisch remobilisierte Asche beeinträchtigt sind. Der kurzzeitige negative Impakt war gravierend, und Umwelt und örtliche Gemeinschaft brauchten 5 Jahre um erkennbare Erholung aufzuweisen. Die Ergebnisse dieser Studie weisen auch auf das Zusammenspiel von Wind, Regen und der Verfügbarkeit von Asche als übergeordnete Kontrollparameter für das Auftreten und die Beständigkeit äolischer Remobilisierung vulkanischer Asche hin

Short and Long-Term Trainability in Older Adults: Training and Detraining Following Two Years of Multicomponent Cognitive-Physical Exercise Training

Despite the benefits of multicomponent physical–cognitive training programs (MCCogTPs), lower training intensities in the concurrent approach, and bigger heterogeneity with aging, suggest the need for long-term analyses, with special attention to training and detraining in older adults. The present study aims to examine these training/detraining effects in a two year MCCogTP, looking for specific dynamics in the trainability of their physical and cognitive capacities. The intervention was divided into four periods: T1, T2 (8 months of training each), and D1, D2 (3.5 months of detraining plus 0.5 of testing each). Twenty-five healthy seniors (70.82 ± 5.18 years) comprised the final sample and were assessed for cardiovascular fitness (6-minutes walking test), lower-limbs strength (30-seconds chair-stand test) and agility (8-feet timed up-and-go test). Inhibition (Stroop test) was considered for executive function. Physical and cognitive status improved significantly (p < 0.05) throughout the two years, with larger enhancements for physical function (mainly strength and agility). Strength and cardiovascular fitness were more sensitive to detraining, whilst agility proved to have larger training retentions. Inhibition followed an initial similar trend, but it was the only variable to improve along D2 (d = 0.52), and changes were not significant within periods. Notwithstanding aging, and the exercise cessation in D2, physical and cognitive status remained enhanced two years later compared to baseline, except for lower-limb strength. According to these results, basic physical capacities are very sensitive to training/detraining, deserving continuous attention (especially strength). Both reducing detraining periods and complementary resistance training should be considered. Additionally, physical enhancements following MCcogTPs may help cognition maintenance during detraining

The globular cluster system of the low-luminosity elliptical galaxy NGC 1427

Washington photometry is presented for a large number of globular cluster candidates associated with the low-luminosity elliptical galaxy NGC 1427 in the Fornax cluster. The survey is mostly complete to T1 = 23.5 (V ≈ 24.0) and includes an areal coverage of about 216 arcmin2, centered near the galaxy. Most previous studies have failed to detect any evidence of multiple globular cluster populations in this low-luminosity elliptical, in sharp contrast to the bimodal globular cluster systems commonly found in giant ellipticals. The lack of multimodal cluster populations has been used as the basis for suggesting that the formation mechanisms for low-luminosity and giant ellipticals are significantly different. Our metallicity-sensitive C-T1 photometry (the first such study of a low-luminosity elliptical) reveals a definite bimodal cluster population. The red globular cluster population appears strongly centrally concentrated and practically disappears beyond a galactocentric radius of 120″. The mean color of these clusters is similar to that of the inner galaxy halo. Blue globulars, on the other hand, exhibit a shallower spatial distribution. These clusters share a small negative C-T1 color gradient with the galaxy halo, although they are, on average, some 0.3 mag bluer at all galactocentric radii. The overall mean cluster system metallicity is -0.9 ± 0.2. The specific globular cluster frequency SN is 4.5 ± 0.8, if a distance modulus (V0 - Mv) = 31.0 is adopted. Our results demonstrate that nonunimodal globular cluster populations exist in low-luminosity ellipticals, as well as in giant ellipticals, and thus that the formation mechanisms for these galaxies may share some similarities.Facultad de Ciencias Astronómicas y Geofísica

Impactos y gestión de erupciones volcánicas en Argentina: una mirada interdisciplinaria sobre el ciclo eruptivo 2018-2019 del volcán Peteroa

Argentina es un extenso país con numerosas evidencias de actividad volcánica. Sin considerar el volcanismo antártico (e.g. Isla Decepción, en las Shetland del Sur), en el país existen 38 volcanes con registro de actividad holocena, 20 enteramente en territorio argentino y 18 en el límite internacional con Chile (García y Badi, 2021). La totalidad de estos sistemas volcánicos activos se encuentran emplazados en el extremo occidental del territorio. Sin embargo, al pensar en las posibles consecuencias de la actividad volcánica en el país, también deben considerarse los más de 70 volcanes activos ubicados íntegramente en territorio chileno (Amigo, 2021). Más allá de los procesos circunscritos a las inmediaciones de los edificios volcánicos (e.g. corrientes piroclásticas, flujos de lava, lahares), el principal peligro volcánico para el territorio argentino es la caída de tefra. En particular, la fracción tamaño ceniza (diámetro 1 km³–, han ocasionado una multiplicidad de impactos adversos, tanto en el ambiente, como en la economía y la vida cotidiana de las personas (Craig et al., 2016). Pero además de estas erupciones de moderada a gran magnitud, en los Andes también ocurren erupciones menores. Este tipo de erupciones, por lo general, no adquieren trascendencia mediática ni ocupan un espacio de relevancia en la agenda pública nacional. Esta invisibilización, en parte, puede entenderse al observar la distribución demográfica de Argentina que indica que los principales núcleos urbanos se encuentran mayormente alejados de los sistemas volcánicos activos. En este sentido, resulta sencillo imaginar que estas pequeñas erupciones, de volcanes emplazados en rincones remotos del país no afectan a nadie. Pero, ¿cuánto de cierto hay en esta afirmación? ¿Qué ocurre con los pobladores rurales que habitan estos territorios? En este trabajo nos adentramos en una de estas áreas remotas de la cordillera de los Andes con el objetivo de dar respuesta a estos interrogantes. Más específicamente, visitamos la cuenca alta del Río Grande en la provincia de Mendoza; zona que fue afectada por la erupción del volcán Peteroa en 2018-2019 (Fig. 1). El interés de nuestra investigación se centra no solo en comprender los efectos de esta erupción en el ambiente y las personas sino también en analizar la gestión de una crisis volcánica en un territorio andino constituido predominantemente por población rural. Para esto conformamos un equipo de trabajo interdisciplinario e implementamos, de manera combinada, herramientas de las ciencias sociales y naturales

Mass flux decay timescales of volcanic particles due to aeolian processes in the Argentinian Patagonia steppe

We investigate the timescales of the horizontal mass flux decay of wind remobilised volcanic particles in Argentina, associated with the tephra-fallout deposit produced by the 2011–2012 Cordón Caulle (Chile) eruption. Particle removal processes are controlled by complex interactions of meteorological conditions, surface properties and particle depletion with time. We find that ash remobilisation follows a two-phase exponential decay with specific timescales for the initial input of fresh ash (1–74 days) and the following soil stabilisation processes (3–52 months). The characteristic timescales as a function of particle size shows two minimum values, identified for sizes around 2 and 19–37 μm, suggesting that these size-range particles are remobilised more easily, due to the interaction between saltation and suspension-induced processes. We find that in volcanic regions, characterised by a sudden release and a subsequent depletion of particles, the availability of wind-erodible particles plays a major role due to compaction and removal of fine particles. We propose, therefore, a simple and reproducible empirical model to describe the mass flux decay of remobilised ash in a supply-limited environment. This methodology represents an innovative approach to link field measurements of multi-sized and supply-limited deposits with saltation erosion theory.The authors are grateful to Paul Jarvis for his comments and corrections of a previous version of this manuscript as well as his insightful discussions. Sampling collection is part of the National Soil Research Program of INTA. This work was supported by the Swiss National Science Foundation (#200021 – 163152).Peer ReviewedPostprint (published version

Análisis espacial de terrenos afectados por minería de suelos en un área del partido de La Plata a partir de índices de vegetación

La actividad extractiva vinculada a la minería de suelos data desde hace más de 100 años en diversos Partidos dentro de la Provincia de Buenos Aires. En el Partido de La Plata, esta actividad ha implicado la pérdida del “capital natural”, en las áreas/cuencas de producción destinadas al abastecimiento de alimentos a los centros urbanos más próximos. Poder cuantificar las áreas degradadas por esta actividad en los entornos de la Ciudad de La Plata y de las grandes ciudades de la Provincia de Buenos Aires contribuiría a la valoración de la problemática, coadyuvando al diseño de estrategias para la protección del recurso y la remediación de los pasivos ambientales generados. A partir de esta situación se cree oportuno poder desarrollar una metodología que permita la identificación, evaluación y valoración de estas áreas degradadas. Las técnicas de análisis espacial y teledetección, en este caso, permiten tener acceso al conocimiento de las situaciones y estado en el que se encuentran las coberturas desde un punto de vista espectral, pudiéndose delimitar de manera preliminar los terrenos que presenten signos de haber sido removido su horizonte superficial, ya sea agentes erosivos naturales o por actividad minera (Fraziers et al., 1989; De Vliegher, 1990; Dubocq et al., 1991). El presente trabajo tiene como objetivo confeccionar Índices de Vegetación (SAVI y NDVI) para 2 momentos del año contrastantes entre sí (otoño – primavera) en un área piloto del Partido de La Plata, con el fin de determinar cubiertas correspondientes a suelos afectados por minería (Suelos Decapitados). A su vez se pretende obtener un valor numérico standard de índice que pueda ser representativo de la situación de decapitación

A Methodological Approach for Testing the Viability of Seeds Stored in Short-Term Seed Banks

[EN] Efficient management of `active¿ seed banks ¿ specifically aimed at the short-term storage at room temperature of seeds to be used locally in conservation/regeneration programmes of endemic or endangered plant species ¿ requires establishing the optimal storage time to maintain high seed viability, for each stored species. In this work, germination of seeds of the halophytes Thalictrum maritimum, Centaurea dracunculifolia and Linum maritimum has been investigated. The seeds had been stored for different periods of time in the seed bank of `La Albufera¿ Natural Park (Valencia, SE Spain) after collection in salt marshes of the Park, where small populations of the three species are present. Seeds of T. maritimum and C. dracunculifolia have a relatively short period of viability at room temperature, and should not be stored for more than three years. On the other hand, L. maritimum seeds maintain a high germination percentage and can be kept at room temperature for up to 10 years. T. maritimum seeds, in contrast to those of the other two species, did not germinate in in vitro tests nor when sown directly on a standard substrate, unless a pre-treatment of the seeds was applied, mechanical scarification being the most effective. These results will help to improve the management of the seed bank, to generate more efficiently new plants for reintroduction and reinforcement of populations of these species in their natural ecosystems within the Natural ParkForte Gil, J.; Yabor, L.; Bellido Nadal, A.; Collado Cerveró, F.; Ferrer-Gallego, P.; Vicente, O.; Boscaiu, M. (2017). A Methodological Approach for Testing the Viability of Seeds Stored in Short-Term Seed Banks. Notulae Scientia Biologicae. 9(4):563-570. doi:10.15835/nsb9410173S5635709

Aeolian Remobilisation of the 2011-Cordón Caulle Tephra-Fallout Deposit: Example of an Important Process in the Life Cycle of Volcanic Ash

Although volcanic eruptions represent short periods in the whole history of a volcano, the large amount of loose pyroclastic material produced, combined with aeolian processes, can lead to continuous, long-lasting reworking of volcanic products. Driven by wind, these processes significantly influence the geomorphology and prolong the impacts of eruptions on exposed communities and ecosystems. Since such phenomena are of interest to scientists from a range of disciplines (e.g., volcanology, atmospheric and soil sciences), a well-defined, common nomenclature is necessary to optimise the multidisciplinary characterisation of both processes and deposits. We, therefore, first describe ash wind-remobilisation processes and provide definitions for appropriate terms consistent with the World Meteorological Organisation’s (WMO’s) classification of lithometeors. Second, we apply these definitions to investigate aeolian remobilisation of the 2011 Cordón Caulle (Chile) tephra-fallout deposit, which has strongly impacted rural communities in the Argentinian Patagonia steppe. We combine field observations and a physical characterisation of systematically collected ground and airborne material in order to identify the secondary deposits associated with: (i) non-erodible surface roughness elements (e.g., vegetation and rocks) and (ii) pre-existing mounds or similar erodible bedforms. Grainsize analysis shows that wind-remobilised particles have a specific size range, from <0.4 to 500 mm, with a 95% of the material between 1 and 255 mm, median values of 25–135 mm and modes of 30–95 mm. We find that 15– 40% of the remobilised material ranges from 63–125 mm, coinciding with the size range which minimises the wind threshold friction velocity. Interestingly, particle shape analysis shows that for this size fraction, remobilised particles display the largest differences in shape descriptors (convexity, solidity and circularity) with respect to the primary ash, indicating abrasion and rounding due to saltation. Although particle (size and shape) and deposit features (morphology and structures) alone are insufficient to interpret transport mechanisms, their combination suggests that whilst saltation is the most common particle transport mechanism, suspension and creep also play an important role. As well as inferring transport mechanisms from this combined approach, we also demonstrate how the correlation of the primary volcanic source with the associated remobilised deposits is fundamental to our understanding of the life cycle of volcanic ash.Estación Experimental Agropecuaria BarilocheFil: Dominguez, Lucia. University of Geneva. Department of Earth Sciences; SuizaFil: Bonadonna, Costanza. University of Geneva. Department of Earth Sciences; SuizaFil: Forte, Pablo. Universidad Nacional de Buenos Aires. Departamento de Ciencias Geologicas; ArgentinaFil: Jarvis, Paul Antony. University of Geneva. Department of Earth Sciences; SuizaFil: Cioni, Raffaello. University of Florence. School of Mathematical, Physical and Natural Sciences. Department of Earth Sciences; ItalyFil: Mingari, Leonardo. Barcelona Supercomputing Center; SpainFil: Bran, Donaldo Eduardo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche; ArgentinaFil: Panebianco, Juan Esteban. Universidad Nacional de La Pampa. Instituto de Ciencias de la Tierra y Ambientales de La Pampa. Consejo Nacional de Investigaciones Cietíficas y Técnicas; Argentin

Assessing the impact of volcanic gases in the village of Copahue, Argentina

The village of Copahue (Neuquén Province, Argentina) is located in the Andean range, on one of the largest geothermal fields in the country: the Caviahue ? Copahue Volcanic Complex (CCVC). Copahue village was conceived and developed as a touristic destination centered on thermal baths and wellness activities. Currently, it receives more than 18,000 visitors per year.Fluid emissions in the CCVC are fed by a hydrothermal reservoir located at 800 m depth, mostly recharged by meteoric water and heated by a magma chamber, located at ~5 km depth. Thermal fluids in Copahue are discharged as fumaroles, diffuse degassing sites, boiling and bubbling pools. Diffuse emissions silently emit more than 100 tons of CO2 per day over the entire area of this town (~0.5 km2). Diffuse CO2 degassing anomalies indicate a strong structural control, with gas rising through fault planes and areas of high structural damage.Recently, members of the community expressed their concern about the increasing presence of fluid discharges nearby and under the foundations of commercial, residential and public buildings. The discharge of these thermal fluids is causing severe damage to buildings and infrastructure, and it constitutes a potential threat for human health. Considering this scenario, the aims of this work are: (i) to identify areas within the town of high fluid flow, (ii) to generate thermal emissions hazard maps and (iii) to assess the impact of volcanic gases on people as well as physical damage to buildings, caused by the thermal fluid discharges. The identification of areas with high fluid flow and the elaboration of hazard maps was carried out by combining multiple map layers (CO2 flux, soil temperature and urban maps) and sets of data points (point-based thermal emissions and damaged buildings within the urban area). The assessment of the physical damage on people and assets was evaluated by performing a visual recognition of the various impacts of hydrothermal gases on buildings, and by collecting audiovisual material along with anecdotal information provided by the Copahue community.The combination of the multiple map layers reveals two main areas of high CO2 release within the village of Copahue, located in the center and in the southern portion of the village. The overlaying of data points on the map layers shows that the damaged buildings are located within the southern-most CO2 diffuse degassing and thermal anomaly area.Numerous buildings present problems caused by outpouring of vapor and gaseous chemicals on floors and walls, infiltrations of fluids in joints and overheated rooms, among other issues. The impact of these geothermal events on human health is yet to be assessed.The results of this work will raise awareness among decision makers and civil protection authorities, and will establish a framework for planning land-use, ultimately fostering a safer coexistence between the population the active volcanic - geothermal field.Fil: Lamberti, María Clara Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Forte, Pablo Brian. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Llano, Joaquin. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Albite, Juan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; ArgentinaFil: Trinelli, María Alcira. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; ArgentinaFil: Castro, J.. Johannes Gutenberg Universitat Mainz; AlemaniaFil: Agusto, Mariano Roberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaEGU General Assembly 2019VienaAustriaEuropean Geosciences Unio

T test vs categorical analysis: evolution of agility in older adults following two years of training

Entendiendo que entrenar no siempre significa alcanzar la independencia funcional para un adulto mayor (AM), ni desentrenar perderla, se crearon 4 categorías para valorar el efecto a largo plazo de un programa multicomponente físico-cognitivo sobre el nivel de independencia en sus usuarios. Se evaluaron 25 AM sanos (69.74±5.36 años) a lo largo de dos años, considerando 2 periodos de Entrenamiento (E1, E2; 8 meses cada uno) y Desentrenamiento (D1, D2; 3 meses + 1 de evaluación). Se analizó la agilidad (Time Up&Go Test) por su relación con la marcha y la prevención de caídas. Los cambios de categoría entre periodos se analizaron mediante el test exacto de Fisher, seguido de un ANOVA de medidas repetidas para comparar el análisis tras ambos enfoques. Aunque la agilidad mostró una mejora significativa al entrenar, mayor en E1 que en E2, el porcentaje de participantes independientes funcionalmente fue mayor en E2. En términos de desentrenamiento, la comparación por pares mostró pérdidas superiores durante D2, aunque esto no impidió que más de la mitad de los participantes alcanzaran la independencia funcional en este segundo periodo. Ambos análisis son complementarios y clarifican el beneficio del programa a largo plazo en la agilidad de la población adulta.Exercise training does not ensure functional independence among elders, neither detraining means to lose it, so 4 categories where designed in order to analyse the long-term effects of a multicomponent physical-cognitive training program over their users’ functional independence. A total of 25 healthy elders (69.74±5.36 years old) were assessed during two years, including 2 periods of training (T1, T2; 8 months each one) and detraining (D1, D2; 3 months + 1 of testing). Agility (Time Up&Go Test) was analysed because of its relationship with gait and fall-prevention. The exact Fisher’s test was considered to analzse between-period category changes, followed by a Repeated Measures ANOVA, to compare the results in both approaches. Although agility showed significant improvements following training, larger in T1 compared to T2, the percentage of independent participants was higher in T2. In terms of detraining, paired comparison showed larger losses during D2. However, more than half of participants reached the physical independence during this second period. Both analyses are complementary and clarify the long-term benefits of this training program for the agility of the elderly population