196 research outputs found
Cognitive function and mood at high altitude following acclimatization and use of supplemental oxygen and adaptive servoventilation sleep treatments.
Impairments in cognitive function, mood, and sleep quality occur following ascent to high altitude. Low oxygen (hypoxia) and poor sleep quality are both linked to impaired cognitive performance, but their independent contributions at high altitude remain unknown. Adaptive servoventilation (ASV) improves sleep quality by stabilizing breathing and preventing central apneas without supplemental oxygen. We compared the efficacy of ASV and supplemental oxygen sleep treatments for improving daytime cognitive function and mood in high-altitude visitors (N = 18) during acclimatization to 3,800 m. Each night, subjects were randomly provided with ASV, supplemental oxygen (SpO2 > 95%), or no treatment. Each morning subjects completed a series of cognitive function tests and questionnaires to assess mood and multiple aspects of cognitive performance. We found that both ASV and supplemental oxygen (O2) improved daytime feelings of confusion (ASV: p < 0.01; O2: p < 0.05) and fatigue (ASV: p < 0.01; O2: p < 0.01) but did not improve other measures of cognitive performance at high altitude. However, performance improved on the trail making tests (TMT) A and B (p < 0.001), the balloon analog risk test (p < 0.0001), and the psychomotor vigilance test (p < 0.01) over the course of three days at altitude after controlling for effects of sleep treatments. Compared to sea level, subjects reported higher levels of confusion (p < 0.01) and performed worse on the TMT A (p < 0.05) and the emotion recognition test (p < 0.05) on nights when they received no treatment at high altitude. These results suggest that stabilizing breathing (ASV) or increasing oxygenation (supplemental oxygen) during sleep can reduce feelings of fatigue and confusion, but that daytime hypoxia may play a larger role in other cognitive impairments reported at high altitude. Furthermore, this study provides evidence that some aspects of cognition (executive control, risk inhibition, sustained attention) improve with acclimatization
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Relationships Between Chemoreflex Responses, Sleep Quality, and Hematocrit in Andean Men and Women.
Andean highlanders are challenged by chronic hypoxia and many exhibit elevated hematocrit (Hct) and blunted ventilation compared to other high-altitude populations. While many Andeans develop Chronic Mountain Sickness (CMS) and excessive erythrocytosis, Hct varies markedly within Andean men and women and may be driven by individual differences in ventilatory control and/or sleep events which exacerbate hypoxemia. To test this hypothesis, we quantified relationships between resting ventilation and ventilatory chemoreflexes, sleep desaturation, breathing disturbance, and Hct in Andean men and women. Ventilatory measures were made in 109 individuals (n = 63 men; n = 46 women), and sleep measures in 45 of these participants (n = 22 men; n = 23 women). In both men and women, high Hct was associated with low daytime SpO2 (p < 0.001 and p < 0.002, respectively) and decreased sleep SpO2 (mean, nadir, and time <80%; all p < 0.02). In men, high Hct was also associated with increased end-tidal PCO2 (p < 0.009). While ventilatory responses to hypoxia and hypercapnia did not predict Hct, decreased hypoxic ventilatory responses were associated with lower daytime SpO2 in men (p < 0.01) and women (p < 0.009) and with lower nadir sleep SpO2 in women (p < 0.02). Decreased ventilatory responses to CO2 were associated with more time below 80% SpO2 during sleep in men (p < 0.05). The obstructive apnea index and apnea-hypopnea index also predicted Hct and CMS scores in men after accounting for age, BMI, and SpO2 during sleep. Finally, heart rate response to hypoxia was lower in men with higher Hct (p < 0.0001). These data support the idea that hypoventilation and decreased ventilatory sensitivity to hypoxia are associated with decreased day time and nighttime SpO2 levels that may exacerbate the stimulus for erythropoiesis in Andean men and women. However, interventional and longitudinal studies are required to establish the causal relationships between these associations
Stratigraphic relationship between the Quebrada de los Colorados and Angastaco Formations (Paleogene-Neogene), Calchiquies Valleys, Salta (Argentina): its significance in the analysis of the Pallogastilla Group basin
El Grupo Payogastilla representa el registro sedimentario de la cuenca de antepaís andina en los Valles Calchaquíes. La Formación Quebrada de los Colorados, unidad basal, es de singular importancia debido a que preserva evidencias de los primeros episodios de contracción con deformación intracuencal, cambios en las áreas de aporte y asociaciones de fósiles que la datan paleógena pre-oligocena, hecho que llevó a replantear el modelo de cuenca de antepaís propuesto para el Noroeste argentino. Asimismo, la suprayacente Formación Angastaco, además de contener similar registro tectono-sedimentario, documenta el inicio del magmatismo en el borde oriental de la Puna. Los recientes trabajos de investigación llevados a cabo en estas unidades han permitido identificar y mapear superficies de discontinuidad sedimentaria, incluso de discordancias que obligan a modificar el cuadro estratigráfico existente. En la presente contribución se describen las relaciones estratigráficas de la Formación Quebrada de los Colorados con el objetivo de actualizar el conocimiento sobre la misma y discutir el esquema estratigráfico actualmente vigente. Esta formación se asienta en relación de discordancia y de disconformidad sobre las Formaciones Lumbrera, Maíz Gordo y Mealla (Subgrupo Santa Bárbara) y sobre el Subgrupo Pirgua, del Grupo Salta. Asimismo, se describe y discute el alcance de la identificación de una discontinuidad sedimentaria intra-Quebrada de los Colorados, señalada por el cambio abrupto de facies sedimentarias y la presencia de una superficie de meteorización con desarrollo de una calcreta. Esta superficie separa una sucesión netamente fluvial de otra fluvio-eólica con características sedimentarias distintivas. Por último, se describen las relaciones de transición y de concordancia entre la sucesión fluvio-eólica con la suprayacente Formación Angastaco. En base a estas relaciones se propone redefinir la Formación Angastaco con la incorporación de la sucesión fluvio-eólica con el rango de Miembro Tin Tin y retomar la definición original del Miembro Las Flechas. Finalmente y en base la nueva información disponible se propone a la quebrada Grande (área de cerro Tin Tin) como hipoestratotipo para la Formación Quebrada de los Colorados, localidad que servirá como complemento de las descripciones originales.The sedimentary record of the Andean orogenic basins in the Calchaquies Valleys (Fig. 1), consists of nearly 6000 m of an overall coarsening and thickening upward clastic succession (Díaz and Malizzia, 1983) known as the Payogastilla Group. The Payogatilla Group is composed of the Quebrada de los Colorados, Angastaco, Palo Pintado and San Felipe Formations (Díaz and Malizzia, 1983; Díaz et al., 1987 - see Fig. 2). Our investigation and previous research in the Quebrada de los Colorados Formation (e.g. Galli and Hernández, 1999; Coutand et al., 2006; Carrapa et al., 2011a,b; Galli et al., 2011) allowed the identification of several unconformity surfaces, including an angular relationship between the Quebrada de los Colorados Formation and the underlying Salta Group. Moreover, the identification of an intra-formational unconformity led us to the reconsideration of the stratigraphic scheme of the Payogastilla Group. Here, we address the regional stratigraphic relations of the Quebrada de los Colorados Formation, the lower unit of the Payogastilla Group, in order to update the knowledge and to discuss the validity of the present stratigraphic framework.
Along the Calchaquies Valleys, the Quebrada de los Colorados Formation rests on different units of the Salta Group. The more frequent relation is with the uppermost unit, the Lumbrera Formation (Fig. 3), but in some areas, for example at Saladillo, the Quebrada de los Colorados Formation rests in angular relationship on the Maíz Gordo Formation (del Papa et al., 2004), as in the Esquina Azul locality (Fig. 4). In the cerro Bayo site, the Quebrada de los Colorados Formation lies also upon the Maíz Gordo Formation but few meters laterally directly overlays the Mealla Formation (Figs. 2 and 4). In other places, like in the Pucará valley (Fig. 1), the Quebrada de los Colorados overlays the Pirgua Subgroup (Villanueva García, 1992; Sabino, 2004). These variable stratigraphic relationships are key features that document the tectonic inversion of the Salta Group contemporaneous with the Quebrada de los Colorados sedimentation.
The Quebrada de los Colorados Formation consists of red fine-grained floodplain facies and sandy to gravelly clastic fluvial channels facies (Fig. 6). The original description of this unit includes an eolian succession in the upper section (Díaz and Malizzia, 1983). In some localities, like at Tin Tin and Tonco (Fig. 1), the eolian and fluvio-eolian successions have thicknesses ranging from 450 to 600 m (Starck and Vergani, 1996; del Papa et al., 2013) representing a very distinctive erg record. The contact with the underlying fluvial deposits is sharp and a calcrete paleosol (Fig. 5) is locally recognized suggesting the presence of an unconformity within the Quebrada de los Colorados Formation. Moreover, this fluvio-eolian succession has a transitional contact with the overlying fluvial conglomeratic facies of the Angastaco Formation. This stratigraphic relation suggests that the former could be formally included within the Angastaco Formation. Thus we propose a redefinition of the Angastaco Formation (Díaz and Malizzia, 1983; nom. transl. Díaz et al., 1987); including the fluvio-eolian succession as the basal Tin Tin Member and to return to the previously defined Las Flechas Member. We propose the Tin Tin area (25º13'51.6'' Lat. S and 66º00'58.5'' Log. W - 25°16'12'' Lat. S and 66°2'39.45'' Log. W) as stratotype area (Fig. 7). In this locality, pale red silty sandstones to siltstones overlie coarse conglomeratic strata (Figs. 5 and 6) and are overlain by white eolian sandstones that grade to gray conglomeratic strata of the Angastaco Formation sensu Díaz and Malizzia (1983). The age of the Tin Tin Member is considered late Oligocene to early Miocene according to the 21 Ma U/Pb zircon datings (Carrapa et al., 2011a; del Papa et al., 2013).
Finally we propose the Quebrada Grande locality (25º12'59.1'' Lat. S and 66º01'33.1'' Log. W), along state route Nº 42, Tin Tin area, Calchaquí Valley (Fig. 7) as hypostratotype of the Quebrada de los Colorados Formation. In this locality, this unit rests unconformably, and locally through an angular unconformity, on the Lumbrera Formation (Salta Group, Figs. 2, 3 and 4). In this area the formation is 792 m thick and is characterized by two coarsening upward successions of red siltstone, lenticular to shallow lenticular coarse sandstones and horizontally stratified conglomerates (Fig. 5). Based on mammalian biostratigraphy recorded at sites in Cerro Bayo, Tin Tin and Luracatao (Fig. 1) the age of the Quebrada de los Colorados Formation is Casamayoran (sub-age Barrancan), SALMA, suggesting a Middle Eocene age for the basal levels (Powell et al., 2011).
In summary, we propose that the fluvio-eolian section of the Quebrada de los Colorados Formation should be incorporated into the Angastaco Formation, as the Tin Tin Member. This modification will simplify recognition in the field, mapping, and genetic interpretation of these foreland basin deposits.Fil: del Papa, Cecilia Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Ciencias de la Tierra; Argentina. Universidad Nacional de Córdoba; ArgentinaFil: Hongn, Fernando Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Bio y Geociencias del Noroeste Argentino; Argentina. Universidad Nacional de Salta; ArgentinaFil: Payrola Bosio, Patricio Augusto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Bio y Geociencias del Noroeste Argentino; Argentina. Universidad Nacional de Salta; ArgentinaFil: Powell, Jaime Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Tucumán; ArgentinaFil: Deraco, Maria Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Tucumán; ArgentinaFil: Herrera, Claudia Marcela Reina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Tucumán; Argentin
No Excess of RR Lyrae Stars in the Canis Major Overdensity
Our multi-epoch survey of ~20 sq. deg. of the Canis Major overdensity has
detected only 10 RR Lyrae stars (RRLS). We show that this number is consistent
with the number expected from the Galactic halo and thick disk populations
alone, leaving no excess that can be attributed to the dwarf spheroidal (dSph)
galaxy that some authors have proposed as the origin of the CMa overdensity. If
this galaxy resembles the dSph satellites of the Milky Way and of M31 and has
the putative Mv~-14.5, our survey should have detected several tens of RRLS.
Even if Mv10, which is not observed. Either the
old stellar population of this galaxy has unique properties or, as others have
argued before, the CMa overdensity is produced by the thin and thick disk and
spiral arm populations of the Milky Way and not by a collision with a dSph
satellite galaxy.Comment: 35 pages, 9 figures, 5 tables. Accepted for publication at the
Astronomical Journa
Citizen Science as Democratic Innovation That Renews Environmental Monitoring and Assessment for the Sustainable Development Goals in Rural Areas
This commentary focuses on analyzing the potential of citizen science to address legitimacy issues in the knowledge base used to guide transformative governance in the context of the United Nation's Sustainable Development Goals (henceforth SDGs). The commentary develops two interrelated arguments for better understanding the limits of what we term "traditional" Environmental Monitoring and Assessment (EMA) as well as the potential of citizen science (CS) for strengthening the legitimacy of EMA in the local implementation of SDGs. We start by arguing that there is an urgent need for a profound renewal of traditional EMA to better implement the SDGs. Then, we present CS as a democratic innovation that provides a path to EMA renewal that incorporates, develops, and extends the role of CS in data production and use by EMA. The commentary substantiates such arguments based on current approaches to CS and traditional EMA. From this starting point, we theorize the potential of CS as a democratic innovation that can repurpose EMA as a tool for the implementation of the SDGs. With a focus on the implementation of SDG15 (Life on Land) in local contexts, the commentary presents CS as a democratic innovation for legitimate transformative governance that can affect socio-ecological transitions. We see this approach as especially appropriate to analyze the implementation of SDGs in rural settings where a specific resource nexus can create conflict-laden contexts with much potential for a renewed EMA to support transformative governance towards Agenda 2030
Engaging domestic abuse practitioners and survivors in a review of outcome tools – reflections on differing priorities
Researchers often develop and decide upon the measurement tools for assessing outcomes related to domestic abuse interventions. However, it is known that clients, service providers and researchers have different ideas about the outcomes that should be measured as markers of success. Evidence from non-domestic abuse sectors indicates that engagement of service providers, clients and researchers contributes to more robust research, policy and practice. We reflect on what we have learnt from the engagement of practitioners and domestic abuse survivors in a review of domestic abuse measurement tools where there were clear differences in priorities between survivors, practitioners and researchers about the ideal measurement tools. The purpose of this reflective article is to support the improvement of future outcome measurement from domestic abuse interventions, while ensuring that domestic abuse survivors do not relive trauma because of measurement
Mobility of Transgenic Nucleic Acids and Proteins within Grafted Rootstocks for Agricultural Improvement
Grafting has been used in agriculture for over 2000 years. Disease resistance and environmental tolerance are highly beneficial traits that can be provided through use of grafting, although the mechanisms, in particular for resistance, have frequently been unknown. As information emerges that describes plant disease resistance mechanisms, the proteins, and nucleic acids that play a critical role in disease management can be expressed in genetically engineered (GE) plant lines. Utilizing transgrafting, the combination of a GE rootstock with a wild-type (WT) scion, or the reverse, has the potential to provide pest and pathogen resistance, impart biotic and abiotic stress tolerance, or increase plant vigor and productivity. Of central importance to these potential benefits is the question of to what extent nucleic acids and proteins are transmitted across a graft junction and whether the movement of these molecules will affect the efficacy of the transgrafting approach. Using a variety of specific examples, this review will report on the movement of organellar DNA, RNAs, and proteins across graft unions. Attention will be specifically drawn to the use of small RNAs and gene silencing within transgrafted plants, with a particular focus on pathogen resistance. The use of GE rootstocks or scions has the potential to extend the horticultural utility of grafting by combining this ancient technique with the molecular strategies of the modern era
Relaciones estratigráficas de las formaciones Quebrada de los Colorados y Angastaco (Paleógeno-Neógeno), Valles Calchaquíes, Salta (Argentina): significadoen el análisis de la cuenca del Grupo Payogastilla
El Grupo Payogastilla representa el registro sedimentario de la cuenca de antepaís andina en los Valles Calchaquíes. La Formación Quebrada de los Colorados, unidad basal, es de singular importancia debido a que preserva evidencias de los primeros episodios de contracción con deformación intracuencal, cambios en las áreas de aporte y asociaciones de fósiles que la datan paleógena pre-oligocena, hecho que llevó a replantear el modelo de cuenca de antepaís propuesto para el Noroeste argentino. Asimismo, la suprayacente Formación Angastaco, además de contener similar registro tectono-sedimentario, documenta el inicio del magmatismo en el borde oriental de la Puna. Los recientes trabajos de investigación llevados a cabo en estas unidades han permitido identificar y mapear superficies de discontinuidad sedimentaria, incluso de discordancias que obligan a modificar el cuadro estratigráfico existente. En la presente contribución se describen las relaciones estratigráficas de la Formación Quebrada de los Colorados con el objetivo de actualizar el conocimiento sobre la misma y discutir el esquema estratigráfico actualmente vigente. Esta formación se asienta en relación de discordancia y de disconformidad sobre las Formaciones Lumbrera, Maíz Gordo y Mealla (Subgrupo Santa Bárbara) y sobre el Subgrupo Pirgua, del Grupo Salta. Asimismo, se describe y discute el alcance de la identificación de una discontinuidad sedimentaria intra-Quebrada de los Colorados, señalada por el cambio abrupto de facies sedimentarias y la presencia de una superficie de meteorización con desarrollo de una calcreta. Esta superficie separa una sucesión netamente fluvial de otra fluvio-eólica con características sedimentarias distintivas. Por último, se describen las relaciones de transición y de concor- dancia entre la sucesión fluvio-eólica con la suprayacente Formación Angastaco. En base a estas relaciones se propone redefinir la Formación Angastaco con la incorporación de la sucesión fluvio-eólica con el rango de Miembro TinTin y retomar la definición original del Miembro Las Flechas. Finalmente y en base la nueva información disponible se propone a la quebrada Grande (área de cerro TinTin) como hipoestratotipo para la Formación Quebrada de los Colorados, localidad que servirá como complemento de las descripciones originales
Engaging domestic abuse practitioners and survivors in a review of outcome tools:– reflections on differing priorities
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