Toward the detection of permafrost using land-surface temperature mapping

Permafrost is degrading under current warming conditions, disrupting infrastructure, releasing carbon from soils, and altering seasonal water availability. Therefore, it is important to quantitatively map the change in the extent and depth of permafrost. We used satellite images of land-surface temperature to recognize and map the zero curtain, i.e., the isothermal period of ground temperature during seasonal freeze and thaw, as a precursor for delineating permafrost boundaries from remotely sensed thermal-infrared data. The phase transition of moisture in the ground allows the zero curtain to occur when near-surface soil moisture thaws or freezes, and also when ice-rich permafrost thaws or freezes. We propose that mapping the zero curtain is a precursor to mapping permafrost at shallow depths. We used ASTER and a MODIS-Aqua daily afternoon land-surface temperature (LST) timeseries to recognize the zero curtain at the 1-km scale as a "proof of concept. " Our regional mapping of the zero curtain over an area around the 7000 m high volcano Ojos del Salado in Chile suggests that the zero curtain can be mapped over arid regions of the world. It also indicates that surface heterogeneity, snow cover, and cloud cover can hinder the effectiveness of our approach. To be of practical use in many areas, it may be helpful to reduce the topographic and compositional heterogeneity in order to increase the LST accuracy. The necessary finer spatial resolution to reduce these problems is provided by ASTER (90 m).Fil: Batbaatar, Jigjidsurengiin. University of Washington; Estados UnidosFil: Gillespie , Alan R.. University of Washington; Estados UnidosFil: Sletten, Ronald S.. University of Washington; Estados UnidosFil: Mushkin , Amit. University of Washington; Estados UnidosFil: Amit, Rivka. Geological Survey Of Israel; IsraelFil: Trombotto, Dario Tomas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Liu , Lu. University of Washington; Estados UnidosFil: Petrie, Gregg. University of Washington; Estados Unido

Factors controlling the water quality of rock glacier springs in European and American mountain ranges

Rock glaciers (RGs) provide significant water resources in mountain areas under climate change. Recent research has highlighted high concentrations of solutes including trace elements in RG-fed waters, with negative implications on water quality. Yet, sparse studies from a few locations hinder conclusions about the main drivers of solute export from RGs. Here, in an unprecedented effort, we collected published and unpublished data on rock glacier hydrochemistry around the globe. We considered 201 RG springs from mountain ranges across Europe, North and South America, using a combination of machine learning, multivariate and univariate analyses, and geochemical modeling. We found that 35 % of springs issuing from intact RGs (containing internal ice) have water quality below drinking water standards, compared to 5 % of springs connected to relict RGs (without internal ice). The interaction of ice and bedrock lithology is responsible for solute concentrations in RG springs. Indeed, we found higher concentrations of sulfate and trace elements in springs sourcing from intact RGs compared to water originating from relict RGs, mostly in specific lithological settings. Enhanced sulfide oxidation in intact RGs is responsible for the elevated trace element concentrations. Challenges for water management may arise in mountain catchments rich in intact RGs, and where the predisposing geology would make these areas geochemical RG hotspots. Our work represents a first comprehensive attempt to identify the main drivers of solute concentrations in RG water

Characterization of T-cell subsets infiltrating post-burn hypertrophic scar tissues

In this study, skin-infiltrating cells were characterized in both the active and remission phases of post-burn hypertrophic scar biopsies. Immunohistochemistry examination of active phase samples showed an abundant presence of Langerhans cells, T cells, macrophages, a low presence of natural killer cells and the lack of B lymphocytes. In active hypertrophic scars T lymphocytes infiltrate deep into the superficial dermis and are also observed in the epidermis: CD3+ cells were present at about 222 +/- 107 per 0.25 mm2. In particular the analysis of lymphocyte subpopulations showed that CD4+ T cells predominate in the dermis as well as in the epidermis of active hypertrophic scars whereas CD8+ cells were less well represented (CD4/CD8 ratio is 2.06). This distribution was also shown in remission phase samples and in normotrophic scar specimens, although the lymphocyte number was significantly lower. Approximately 70 per cent of T lymphocytes present in the tissue involved in active phase hypertrophic scar samples were activated (positive with anti-HLA-DR and IL-2 receptor antibodies) which is significantly higher than remission phase hypertrophic and normotrophic scars, in which positivity was 40 and 38 per cent, respectively. Upon activation, the lesional lymphocytes release several cytokines, locally and transiently, that interact with specific receptors in response to different stimulation. Central to the immune hypothesis of hypertrophic scars is that some of the T-cell lymphokines act on keratinocytes, fibroblasts and other cell types to induce changes characteristic of these scars. The presence and close proximity of activated T lymphocytes and antigen-presenting cells of various phenotypes in both the epidermis and dermis of hypertrophic tissues provides strong circumstantial evidence of a local immune response. However, the manner in which T cells achieve and maintain their activated state in hypertrophic tissues is not yet known, and both antigen-dependent and independent mechanisms may contribute

Inhibition of keratinocyte apoptosis by IL-15:a new parameter in the pathogenesis of psoriasis?

Abstract Keratinocytes (KC) are important source of and targets for several cytokines. Although KC express IL-15 mRNA, the functional effects of IL-15 on these epithelial cells remain to be dissected. Investigating primary human foreskin KC and HaCaT cells, we show here by semiquantitative RT-PCR and flow cytometric analysis that both translate IL-15 and IL-15R mRNA and express IL-15 and IL-15Rα protein on the cell surface, suggesting that human KC can employ IL-15 for juxtacrine signaling. While IL-15 exerted no significant effect on KC proliferation and IL-6 or IL-8 secretion, IL-15 inhibited both anti-Fas and methylcellulose-induced KC apoptosis in vitro. This is in line with the recognized potent anti-apoptotic effects of IL-15. IL-2, whose receptor shares two components with the IL-15R, failed to inhibit KC apoptosis. Together with the role of IL-15 in sustaining chronic immune reactions, this invited the question of whether a reduction of KC apoptosis by IL-15 may be involved in the pathogenesis of psoriasis, a chronic hyperproliferative inflammatory skin disease characterized by abnormally low KC apoptosis in the epidermis. Remarkably, compared with nonlesional psoriatic skin and skin of healthy volunteers, lesional psoriatic epidermis showed high IL-15 protein expression in the epidermis and enhanced binding activity for IL-15. Therefore, antagonizing the inhibitory effects of IL-15 on KC apoptosis deserves exploration as a novel therapeutic strategy in psoriasis management.</jats:p

Propiedades insecticidas de la ceniza del complejo volcánico Puyehue-Cordón Caulle y su posible impacto ambiental

Se examina el efecto insecticida de las cenizas volcánicas en general y sus efectos ambientales, con especial énfasis en las cenizas acumuladas como consecuencia de la erupción del complejo volcánico Puyehue-Cordón Caulle, que actualmente afecta un área de más de 7,5 millones de hectáreas en la Patagonia Argentina. Se determinó la composición química de las cenizas provenientes del complejo Puyehue- Cordón Caulle por EDS, y se comprobó que los componentes mayoritarios son el O, Si, Al, Fe, Na y K. A través de bioensayos de laboratorio, utilizando dos especies de insectos como modelo biológico, se determinó que las cenizas se adhieren profusamente a la superficie corporal y resultan tóxicas para ambas especies cuando se mezclan con el sustrato en baja concentración. La susceptibilidad a las cenizas difirió entre ambas especies en bioensayos de siete días de exposición continua [CL99(Oryzaephilus surinamensis L.) = 10.25 mg.g-1; CL99((Tribolium castaneum (Herbst)) = 4.96 mg.g-1]. De estos resultados, se desprende que el impacto de la ceniza del complejo Puyehue- Cordón Caulle sobre la comunidad de artrópodos puede ser radical en la fase aguda de la deposición, y que sus efectos podrían ser substancialmente cualitativos en la fase crónica de la exposición. Así también, la recuperación de las poblaciones afectadas por la ceniza en las zonas con clima desértico, donde persiste la ceniza seca, será más lenta, hecho que tendrá consecuencias tangibles a largo plazo para las plantas hospederas de insectos, para la polinización y sobre el desarrollo de las poblaciones de vertebrados insectívoros. En contraste, en las regiones húmedas, la presencia de cenizas representa un cambio manifiesto en el ecosistema debido al aporte de nutrientes, que en combinación con la retención de agua por las cenizas, llevará a la recuperación cuali y cuantitativa de las poblaciones bajo condiciones favorables

Propiedades insecticidas de la ceniza del complejo volc\ue1nico Puyehue-Cord\uf3n Caulle y su posible impacto ambiental: Insecticidal properties of ashes from the volcanic complex Puyehue-Caulle Range and their possible environmental impact

Se examina el efecto insecticida de las cenizas volcánicas en general y sus efectos ambientales, con especial énfasis en las cenizas acumuladas como consecuencia de la erupción del complejo volcánico Puyehue-Cordón Caulle, que actualmente afecta un área de más de 7,5 millones de hectáreas en la Patagonia Argentina. Se determinó la composición química de las cenizas provenientes del complejo Puyehue-Cordón Caulle por EDS, y se comprobó que los componentes mayoritarios son el O, Si, Al, Fe, Na y K. A través de bioensayos de laboratorio, utilizando dos especies de insectos como modelo biológico, se determinó que las cenizas se adhieren profusamente a la superfi cie corporal y resultan tóxicas para ambas especies cuando se mezclan con el sustrato en baja concentración. La susceptibilidad a las cenizas difi rió entre ambas especies en bioensayos de siete días de exposición continua [CL99(Oryzaephilus surinamensis L.) = 10.25 mg.g-1; CL99 ((Tribolium castaneum (Herbst)) = 4.96 mg.g-1]. De estos resultados, se desprende que el impacto de la ceniza del complejo Puyehue-Cordón Caulle sobre la comunidad de artrópodos puede ser radical en la fase aguda de la deposición, y que sus efectos podrían ser substancialmente cualitativos en la fase crónica de la exposición. Así también, la recuperación de las poblaciones afectadas por la ceniza en las zonas con clima desértico, donde persiste la ceniza seca, será más lenta, hecho que tendrá consecuencias tangibles a largo plazo para las plantas hospederas de insectos, para la polinización y sobre el desarrollo de las poblaciones de vertebrados insectívoros. En contraste, en las regiones húmedas, la presencia de cenizas representa un cambio manifi esto en el ecosistema debido al aporte de nutrientes, que en combinación con la retención de agua por las cenizas, llevará a la recuperación cuali y cuantitativa de las poblaciones bajo condiciones favorables.<br>This paper discusses the insecticidal effect of volcanic ash and its environmental impact, focusing on the ash accumulated as a result of the eruption of the volcanic complex Puyehue- Caulle Range currently affecting an area of over 7.5 million hectares in the Argentine Patagonia. The chemical composition of ashes from the Puyehue-Caulle Range was analyzed by EDS showing that its major components are O, Si, Al, Fe, Na and K. Laboratory bioassays using two species of insects as a biological model, found that the ashes thoroughly adhere to the insect body surface and are toxic to both species tested, when mixed into the substrate at low concentrations. Susceptibility to ashes differs between the two species when tested in a seven day continuous exposure bioassay [CL99(Oryzaephilus surinamensis L.) = 10.25 mg.g-1; CL99((Tribolium castaneum (Herbst)) = 4.96 mg.g-1]. These results agree with those reported in the literature on effects of volcanic eruptions and suggest that the impact of the ashes from the Puyehue-Caulle Range volcanic complex on the insect community may be radical in the acute deposition phase, with substantial qualitative effects in the chronic phase of exposure. Also, the recovery of populations affected by ash in desert areas where dry ash persists will be slower, and this will have tangible and long-term consequences for insect host plants, pollination and on the development of populations of vertebrate insectivores. By contrast, the presence of ash in humid regions will impact the ecosystem by the addition of nutrients, which in combination with water retention by the ash will lead to a qualitative and quantitative recovery of the populations under favorable conditions