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The Bransfield Basin, a marginal basin located northwest of the Antarctic Peninsula, has been habitually considered as a backarc basin associated with the rollback process that took place along an inactive plate boundary, the South Shetland Trench, where the Antarctic and the Phoenix plates meet. New geophysical and structural data discussed in this paper show that the basin opening is related to a sinistral simple-shear couple between the Scotia and the Antarctic plates, and not to the previously suggested rollback mechanism. The widening of the Bransfield Basin and the lack of trench retreat are causing compression in the South Shetland Islands. Two different neotectonic stress directions, with interchanged stress axes, are found in the area of the South Shetland block., Comisión Interministerial de Ciencia y Tecnología (CICYT) [ANT98-0225 y ANT94-0666], Depto. de Geodinámica, Estratigrafía y Paleontología, Fac. de Ciencias Geológicas, TRUE, pub

Mountain glaciers have generally experienced an accelerated retreat over the last 3 decades as a rapid response to current global warming. However, the response to previous warm periods in the Holocene is not well-described for glaciers of the southern Europe mountain ranges, such as the Pyrenees. The situation during the Medieval Climate Anomaly (900-1300 CE) is particularly relevant since it is not certain whether the southern European glaciers just experienced significant ice loss or whether they actually disappeared. We present here the first chronological study of a glacier located in the Central Pyrenees (NE Spain), Monte Perdido Glacier (MPG), carried out by different radiochronological techniques and a comparison with geochemical proxies from neighbouring palaeoclimate records. The chronological model evidences that the glacier persisted during the Roman period and the Medieval Climate Anomaly. The apparent absence of ice in the past ~ 600 years suggests that any ice accumulated during the Little Ice Age has since ablated. This interpretation is supported by measured concentrations of anthropogenic metals, including Zn, Se, Cd, Hg and Pb, which have concentrations well below those typical of industrial-age ice measured at other glaciers in Europe. This study strengthens the general understanding that warming of the past few decades has been exceptional for the past 2 millennia. © Author(s) 2021.

Deception Island (South Shetland Islands) is one of the most active volcanoes in Antarctica, with more than 15 explosive eruptive events registered over the past two centuries. Recent eruptions (1967, 1969 and 1970) and volcanic unrest episodes in 1992, 1999 and 2014–15 demonstrate that the occurrence of future volcanic activity is a valid and pressing concern for scientists, logistic personnel and tourists that are visiting or are working on or near the island. Over the last few decades, intense research activity has been carried out on Deception Island to decipher the origin and evolution of this very complex volcano. To that end, a solid integration of related scientific disciplines, such as tectonics, petrology, geochemistry, geophysics, geomorphology, remote sensing, glaciology, is required. A proper understanding of the island's evolution in the past, and its present state, is essential for improving the efficiency in interpreting monitoring data recorded during volcanic unrest periods and, hence, for future eruption forecasting. In this chapter, we briefly present Deception Island's most relevant tectonic, geomorphological, volcanological and magmatic features, as well as the results obtained from decades of monitoring the island's seismic activity and ground deformation.

The reliable determination of arsine (AsH3) and phosphine (PH3) in hydrogen (H2), nitrogen (N2) and liquefied petroleum gas (LPG) is of great importance because of its drastic effects on the efficiency of catalysts, as well as the strict regulations associated with health, safety and environmental issues. It is challenging for an analyst to determine the parts per billion of AsH3 and PH3 in H2, N2, and LPG at low and high pressures without collection procedures using adsorption, desorption, and dissolution techniques. To overcome this analytical need an analytical methodology was developed, employing a variable pressure sampler (VPS) coupled to a gas chromatograph (GC) with mass spectrometry (MS) for the identification and quantification of traces of AsH3 and PH3. The instrumentation, tubing and accessories of the VPS were made of passivated steel to avoid losses from absorption of AsH3 and PH3 in the steel which would generate significant analytical problems. The VPS had a homogeneous heating block that prevented analyte losses from condensation. With the VPS, 24 AsH3 and PH3 standards were prepared between 0.005 and 0.1 mg kg−1 in balance of H2, N2 and LPG. The separation and quantification of the analytes was achieved with an improved GC with 4 valves and 5 columns in series that guaranteed the elimination of impurities. The proposed method was optimized in VPS and GC-MS and then validated showing highly accaptable linearity (r2 > 0.9999), detection limits (<0.0009 mg kg−1), limits of quantification (<0.003 mg kg−1), intra-day and inter-day precision and accuracy (<1.14% and ≤3.0% respectively), recovery for the standard addition (86–109%), P values> 0.05 for the test Student's t paired who evaluated the effect of the matrix on pressure and concentration. The speed of analysis was high (<5.2 min). The method was applied to real samples, showing values between 0.005 and 0.1 mg kg−1 and an effect on the efficiency of the Ziegler Natta catalyst between 5 and 56%.

Gum rosin (GR) was used as a natural additive to improve the compatibility between polylactic acid, PLA, and poly(butylene adipate-co-terephthalate, PBAT, blended with 20 wt.% of PBAT (PLA/PBAT). The PBAT was used as a soft component to increase the ductility of PLA and its fracture toughness. The coalescence of the PBAT domains was possible due to the plasticization effect of the GR component. These domains contributed to increasing the toughness of the final material due to the variation and control of the PBAT domains’ size and consequently, reducing the stress concentration points. The GR was used in contents of 5, 10, 15, and 20 phr. Consequently, the flexural properties were improved and the impact resistance increased up to 80% in PLA/PBAT_15GR with respect to the PLA/PBAT formulation. Field emission scanning electron microscope (FESEM) images allowed observing that the size of PBAT domains of 2–3 µm was optimal to reduce the impact stress. Differential scanning calorimetry (DSC) analysis showed a reduction of up to 8C on the PLA melting temperature and up to 5.3C of the PLA glass transition temperature in the PLA/PBAT_20GR formulation, which indicates an improvement in the processability of PLA. Finally, transparent films with improved oxygen barrier performance and increased hydrophobicity were obtained suggesting the potential interest of these blends for the food packaging industry.

The objective of this study was to determine the content of rosmarinic acid (RA), total phenolic compounds (TPC) and antioxidant capacity in Trolox (ACET) in three varieties of basil (Ocimum basilicum L.) employing different doses of potassium in nutrient solution (7, 9, 11 and 13 mmol L-1). It was used a 3 x 4 factorial random block design, where the factors were genotype and concentration of potassium. All the variables analyzed presented a significant difference (p ≤ 0.01). The AR content presented a range of 0.4 to 6.4 mg AR g-1. Values of 1.8 to 15.6 mg AGE g-1 were obtained for TPC content. The results obtained from ACET were 39 to 79.9 mg g-1 and these values were increased in relation to rosmarinic acid content and total phenolic compounds. The variety with the highest content of rosmarinic acid, total phenolics and antioxidant capacity was Red Rubin at 13 mmol L-1. The management of K doses in different varieties of basil supports the synthesis of secondary metabolites that are important for different areas of science, on this wise the increase of basil production and its nutraceutical quality would be an alternative to open new markets focused on food and medical industry., RESUMEN El objetivo de esta investigación fue determinar el contenido de ácido rosmarínico (AR), compuestos fenólicos totales (CFT) y capacidad antioxidante equivalente en Trolox (CAET) en tres variedades de albahaca (Ocimum basilicum L.) aplicando dosis diferentes de potasio en solución nutritiva (7, 9, 11 y 13 mmol L-1). Se utilizó un diseño factorial 3 x 4 en bloques al azar, donde los factores fueron genotipo y concentración de potasio. Todas las variables analizadas presentaron diferencia significativa (p ≤ 0.01). El contenido de AR estuvo presente en un rango de 0.4 a 6.4 mg AR g-1. Se obtuvieron valores de 1.8 a 15.6 mg AGE g-1 para el contenido de CFT. Los resultados obtenidos de CAET fueron de 39 a 79.9 mg g-1 y estos valores se incrementaron en relación al contenido de ácido rosmarínico y compuestos fenólicos totales. La variedad con mayor contenido de ácido rosmarínico, fenólicos totales y capacidad antioxidante fue Red Rubin a 13 mmol L-1. El manejo de dosis de K en diferentes variedades de albahaca favorece la síntesis de metabolitos secundarios importantes para diferentes áreas de ciencia, por lo que el incremento de la producción de albahaca y de su calidad nutracéutica podría ser una alternativa para abrir nuevos mercados enfocados a la industria alimentaria y medicinal.