Tectonic control on rock uplift, exhumation, and topography above an oceanic ridge collision: Southern Patagonian Andes (47°S), Chile

International audienceThe subduction of bathymetric anomalies at convergent margins can profoundly affect subduction dynamics, magmatism, and the structural and geomorphic evolution of the overriding plate. The Northern Patagonian Icefield (NPI) is located east of the Chile Triple Junction at ~47°S, where the Chile Rise spreading center collides with South America. This region is characterized by an abrupt increase in summit elevations and relief that has been controversially debated in the context of geodynamic versus glacial erosion effects on topography. Here we present geomorphic, thermochronological, and structural data that document neotectonic activity along hitherto unrecognized faults along the flanks of the NPI. New apatite (U-Th)/He bedrock cooling ages suggest faulting since 2–3 Ma. We infer the northward translation of an ~140 km long fore-arc sliver—the NPI block—results from enhanced partitioning of oblique plate convergence due to the closely spaced collision of three successive segments of the Chile Rise. In this model, greater uplift occurs in the hanging wall of the Exploradores thrust at the northern leading edge of the NPI block, whereas the Cachet and Liquiñe-Ofqui dextral faults decouple the NPI block along its eastern and western flanks, respectively. Localized extension possibly occurs at its southern trailing edge along normal faults associated with margin-parallel extension, tectonic subsidence, and lower elevations along the Andean crest line. Our neotectonic model provides a novel explanation for the abrupt topographic variations inland of the Chile Triple Junction and emphasizes the fundamental effects of local tectonics on exhumation and topographic patterns in this glaciated landscape

Bioflavonoids in medical cosmetology

Bioflavonoids are natural compounds with a defined antioxidant effect. They are responsible for the characteristic color of fruits and vegetables and have a beneficial effect on both the health of the entire human body and the skin. Sources of bioflavonoids are citrus fruits, dark chocolate, red wine, etc. There are thousands different types of flavonoids known for having many essential functions for the skin, such as reducing aging processes, photoprotection, improving blood supply to the skin, making the skin tan more even, etc

IN SEARCH OF POWER : The Vindelälven-Juhttátahkka Biosphere Reserve in Sweden under the microscope of the Foucauldian Discourse Analysis

The present study focuses on the Vindelälven-Juhttátahkka Biosphere Reserve (BR) in Northern Sweden, which serves as an implementation site of UNESCO’s Man and the Biosphere (MAB) programme. In response to a series of environmental and social problems identified in the specific locale, the area inhabited by both “Swedish” and “Sami” people, is designed to serve henceforth as a learning site for sustainable development. Taking Michel Foucault’s work on discourse and power as a reference point, in this study we analyze the discourse that permeates life in the specific milieu, to understand how power operates in the BR and look for resistance. Following Foucault’s theorization of discourse, the study has employed Foucauldian Discourse Analysis (F.D.A.) on the empirical material, gathered from official documents and interviews with people in the BR. Our research has concluded that by employing its scientific programme, UNESCO’s discourse has managed to a large extent to construct in this place a reality that does not allow a future to be imagined outside of the context of sustainable development. This study has found its participants to be influenced by UNESCO’s discourse and has constrained them from perceiving present or imagining future realities that do not sustain the power of the Swedish state under the global neoliberal rule. Lastly, our research has illustrated that the participants who have been found to respond to their experiences have also been found to resist the discourse permeating the BR.

IN SEARCH OF POWER : The Vindelälven-Juhttátahkka Biosphere Reserve in Sweden under the microscope of the Foucauldian Discourse Analysis

The present study focuses on the Vindelälven-Juhttátahkka Biosphere Reserve (BR) in Northern Sweden, which serves as an implementation site of UNESCO’s Man and the Biosphere (MAB) programme. In response to a series of environmental and social problems identified in the specific locale, the area inhabited by both “Swedish” and “Sami” people, is designed to serve henceforth as a learning site for sustainable development. Taking Michel Foucault’s work on discourse and power as a reference point, in this study we analyze the discourse that permeates life in the specific milieu, to understand how power operates in the BR and look for resistance. Following Foucault’s theorization of discourse, the study has employed Foucauldian Discourse Analysis (F.D.A.) on the empirical material, gathered from official documents and interviews with people in the BR. Our research has concluded that by employing its scientific programme, UNESCO’s discourse has managed to a large extent to construct in this place a reality that does not allow a future to be imagined outside of the context of sustainable development. This study has found its participants to be influenced by UNESCO’s discourse and has constrained them from perceiving present or imagining future realities that do not sustain the power of the Swedish state under the global neoliberal rule. Lastly, our research has illustrated that the participants who have been found to respond to their experiences have also been found to resist the discourse permeating the BR.

In vitro analysis of the activity of human monoamine oxidase type B (hMAOB), treated with the cyanotoxin anatoxin-a: supposed factor of neurodegenerative diseases

In this study, we investigated the hypothesis that an additional source of free radicals may be hydrogen peroxide formed by monoamino oxidase (MAO) -catalyzed deamination of catecholamines. Also, increased MAO-B activity in the brain has been linked to the development of some neurodegenerative diseases. The toxicant we used to treat recombinant human MAO-B enzyme is the cyanotoxin аnatoxin-a. For anatoxin-a is known that it’s an agonist of neuronal acetylcholine receptors with 20 times greater affinity to them compared to the natural neurotransmitter. In this study, we analyzed the effect of anatoxin at various selected concentrations on the activity of recombinant human MAO-B enzyme. The method we use is to analyze the activity of human MAO-B with the fluorimetric reagent Amplex UltraRed and the substrate tyramine hydrochloride. The aim of this study is to analyze the effect of anatoxin-a on the hMAO-B enzyme activity and its influence as a factor for the development and progression of neurodegenerative diseases

Toxicity of cyanobacteria. Organotropy of cyanotoxins and toxicodynamics of cyanotoxins by species

As a result of blooming, some cyanobacteria (Microcystis, Anabaena, Planktothrix, etc.) produce toxins at concentrations that are high enough to poison and even kill animals and humans. According to Annex II of the Framework Directive 2000/60/EC, transformed into the Bulgarian legislation, for the characterization of surface water, at this stage, there are no acceptable limit values for cyanotoxins. Cyanotoxins include some of the strongest natural poisons, including those that could cause rapid death due to respiratory failure. The aim of this publication is an overview of toxic cyanobacteria and toxicity mechanisms

Effects of slab-window, alkaline volcanism, and glaciation on thermochronometer cooling histories, Patagonian Andes

International audienceSouthern Patagonia is a prime example of ongoing oceanic ridge collision and slab-window formation sustained over several million years. The impact of these phenomena on the thermal structure and exhumation of the crust have been mainly assessed with low-temperature thermochronology of bedrock samples. Here, we infer thermal histories from new and existing thermochronological data from the region of most recent ridge collision. In particular, we evaluate the potential far-reaching thermal effects of the evolving slab window, which have previously been considered responsible for patterns of late Miocene reheating associated with back-arc alkaline volcanism. Our model results define protracted cooling since ∼15 Ma and stepwise exhumation since the late Miocene. The pattern of stepwise exhumation closely matches the onset of Patagonian glaciation at 7 Ma and the successive pulse of glacial incision coeval with neotectonic activity since 3–4 Ma that are also documented by independent geological and geomorphological evidence in the region. Importantly, our findings challenge the recently suggested lack of glacial erosion and incision since 5 Ma in this region. Furthermore, in contrast to previous modelling studies, we find that the available data do not evidence a previously proposed northward-propagating heating event associated with alkaline volcanism. We hypothesize that the anomalous alkaline volcanism in the Patagonian back-arc might be related to trench-orthogonal tears aligned with transform faults in the subducting plate. The substantial differences from the previous modelling procedure on some of the same samples is demonstrated to result from an important lack of convergence in model runs

Quantifying Tectonic and Glacial Controls on Topography in the Patagonian Andes (46.5°S) From Integrated Thermochronometry and Thermo‐Kinematic Modeling

The Patagonian Andes have been used to illustrate the dependency of major topographic changes in response to glacial erosion processes dominating over tectonic deformation and uplift. Here, we investigate tectonic and glacial contributors to the erosion history and evolution of topography in the Patagonian Andes at 46.5°S. We present 33 new apatite and zircon (U‐Th)/He (AHe and ZHe, respectively) and fission track (AFT and ZFT, respectively) ages integrated with 46 previously published bedrock thermochronometric ages in a 3D thermo‐kinematic model. Observed thermochronometer ages increase from the eastern flank of the topographic crest of the orogen toward the eastern retro‐foreland basin (from AFT 4–10 Ma, ZHe 4–12 Ma, ZFT 6–14 Ma to AFT 28–32 Ma, ZHe 68–117 Ma). Thermo‐kinematic modeling indicates that spatial gradients in thermochronometric ages can be explained by an up to 100‐km‐wide, parabolic‐shaped pattern in exhumation rates with a maximum rate of 0.5 mm/yr from 15 Ma until the onset of glaciation at ∼7 Ma. Furthermore, model results suggest that the youngest AHe ages require a localized acceleration in erosion from ∼0.5 mm/yr to ∼2.2 mm/yr starting between ∼5 and ∼3 Ma, coeval with intensified glaciation and subduction of the Chile Rise. Our results suggest that the long‐wavelength (∼100 km) topography and erosion patterns are likely controlled by rock uplift above mid‐crustal ramp(s) and subsequent transpression along the Liquiñe‐Ofqui Fault. Superposed on these tectonic processes, Late Cenozoic glaciation resulted in localized and accelerated erosion over wavelengths of <20 km.Key Points: Low‐temperature thermochronology records non‐uniform erosion in the retro‐wedge of the Southern Patagonian Andes. Erosion pattern and long‐wavelength topography are largely a function of regional tectonic activity over the last 15 Myr. Glaciation has modified erosion rates and topography on sub‐valley scales over the last 5–3 Myr.Deutsche Forschungsgemeinschaft (DFG) http://dx.doi.org/10.13039/501100001659MINEDUC | CONICYT | Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT) http://dx.doi.org/10.13039/50110000285

Improvement of <i>Stevia rebaudiana</i> Bertoni <i>In Vitro</i> Propagation and Steviol Glycoside Content Using Aminoacid Silver Nanofibers

The food industry is interested in replacing artificial sweeteners with natural sugars that possess zero calories and carbohydrates and do not cause spikes in blood sugar levels. The steviosides leaves, synthesized at Stevia rebaudiana Bertoni, are 300 times sweeter than common table sugar. Stevia propagation is limited due to the poor viability of the seeds, the long time and low germination rate, and the poor rooting ability of vegetative cuttings. Because of this, an alternative biotechnological method for its reproduction is being studied, such as multiple shoot production through direct organogenesis using nanofibers, formed from a derivative of amino acid valine as a carrier of the biologically active agent silver atoms/particles (NF-1%Ag and NF-2%Ag). The stevia explants were cultured on a medium containing NF-1%Ag and NF-2%Ag at concentrations of 1, 10, 50, and 100 mg L−1. The NF-1%Ag and NF-2%Ag treatment caused hormetic effects on stevia plantlets. At low concentrations of from 1 to 50 mg L−1 of nanofibers, the stimulation of plant growth was observed, with the maximum effect being observed at 50 mg L−1 nanofibers. However, at the higher dose of 100 mg L−1, inhibition of the values of parameters characterizing plant growth was recorded. The presence of nanofibers in the medium stimulates stevia root formatting