Double di ffential fragmentation cross sections measurements of 95 MeV/u 12C on thin targets for hadrontherapy

During therapeutic treatment with heavy ions like carbon, the beam undergoes nuclear fragmentation and secondary light charged particles, in particular protons and alpha particles, are produced. To estimate the dose deposited into the tumors and the surrounding healthy tissues, an accurate prediction on the fluences of these secondary fragments is necessary. Nowadays, a very limited set of double di ffential carbon fragmentation cross sections are being measured in the energy range used in hadrontherapy (40 to 400 MeV/u). Therefore, new measurements are performed to determine the double di ffential cross section of carbon on di erent thin targets. This work describes the experimental results of an experiment performed on May 2011 at GANIL. The double di ffential cross sections and the angular distributions of secondary fragments produced in the 12C fragmentation at 95 MeV/u on thin targets (C, CH2, Al, Al2O3, Ti and PMMA) have been measured. The experimental setup will be precisely described, the systematic error study will be explained and all the experimental data will be presented.Comment: Submitted to PR

Unravelling Antarctica’s past through the stratigraphy of a deep ice core: an image-analysis study of the EPICA-DML line-scan images

Polar ice research has undergone great progress in the last six decades. One of its recent technological achievements has been the development of new techniques for digital image recording and analysis of ice-core stratigraphy and microstructure. In this work we investigate one such image records, namely the line-scan image records of the EPICA-DML (European Project for Ice Coring in Antarctica, Dronning Maud Land) deep ice core. These images provide a multiscale depiction of the stratigraphy and structure of the Antarctic Ice Sheet. While previous studies have focused on the ice-core optical stratigraphy on the micro- and mesoscale (<1 mm and 10−3–1 m, respectively), in this work we present several methods to obtain fast and reliable information on the ice-core stratigraphy on the macroscale (1–103 m), including the full ice-sheet thickness. The paleoclimatic relevance of the ice-core optical stratigraphy on the macroscale is demonstrated through the comparison of the line-scan grey-value record of the EPICA-DML deep ice core with its mineral dust record, which is used as a proxy for microinclusions and for several other types of climate proxies. Additionally, we introduce a novel method to estimate the macroscopic air-bubble concentration (including number and size of bubbles) in ice cores, which is simpler, faster, and almost as reliable as painstaking microscopic studies. After a brief excursion on the relation between macroscopic and mesoscopic measures of optical stratigraphy, we close this work by making the case for a multi-measure analysis of ice-core line-scan images, which enables us to obtain a broad perspective of the optical stratigraphy of the whole ice core, with relevance for paleoclimate and ice-sheet-flow studies.This research is supported by the Spanish Government through the María de Maeztu excellence accreditation 2018–2022 (Ref. MDM-2017-0714), and by the Basque Government through the BERC 2018–2021 programme. SHF acknowledges support from the Spanish Ministry of Science, Innovation, and Universities (MCIU) through the project iMechPro (RTI2018–100696–B–I00), and from the Ramón y Cajal grant RYC–2012–12167 of the Spanish Ministry of Economy, Industry and Competitiveness (MINECO

Restraint Stress Alters Expression of Glucocorticoid Bioavailability Mediators, Suppresses Nrf2, and Promotes Oxidative Stress in Liver Tissue.

Hepatic glutathione synthesis and antioxidant protection are critically important for efficient detoxification processes in response to metabolic challenges. However, this biosynthetic pathway, regulated by nuclear factor (erythroid-derived 2)-like 2 (Nrf2), previously demonstrated paradoxical repression following exposure to glucocorticoid stress hormones in cultured hepatic cells. Therefore, the present study used an in vivo model of sub-acute psychological stress to investigate the relationship between hepatic corticosteroid regulation and antioxidant systems. Male Wistar rats were kept under control conditions or subjected to six hours of restraint stress applied for 1 or 3 days (n = 8 per group) after which the liver was isolated for assays of oxidative/nitrosative status and expression of corticosteroid regulatory and Nrf2-antioxidant response element pathway members. A single stress exposure produced a significant increase in the expression of corticosterone reactivator, 11-beta-hydroxysteroid dehydrogenase 1 (11β-Hsd1), while the 11β-Hsd2 isozyme and corticosteroid-binding globulin were down-regulated following stress, indicative of an elevated availability of active corticosterone. Exposure to restraint significantly decreased hepatic concentrations of total cysteine thiols and the antioxidant reduced glutathione on Day 1 and increased 3-nitrotyrosinated and carbonylated proteins on Day 3, suggestive of oxidative/nitrosative stress in the liver following stress exposure. Conversely, there was a sustained down-regulation of Nrf2 mRNA and protein in addition to significant reductions in downstream glutamate-cysteine ligase catalytic subunit (Gclc), the rate-limiting enzyme in glutathione synthesis, on Day 1 and 3 of stress treatment. Interestingly, other antioxidant genes including superoxide dismutase 1 and 2, and glutathione peroxidase 4 were significantly up-regulated following an episode of restraint stress. In conclusion, the results of the present study indicate that increased expression of 11β-Hsd1, indicative of elevated tissue glucocorticoid concentrations, may impair the Nrf2-dependent antioxidant response

Mineral potential of the Amazon: problems and challenges

Los bienes minerales son imprescindibles para la humanidad desde los inicios de la civilización, y los recursos minerales serán siempre necesarios, y en una proporción cada vez mayor. La Amazonia, cerca de la mitad del territorio brasileño, representa la última frontera mineral importante del planeta. La región posee un potencial minero enorme, poco aprovechado. Se están probando nuevos modelos para la formación de depósitos minerales, existiendo la posibilidad de que en un futuro la Amazonia se caracterice como una província mineral productora de cobre, molibdeno y oro. Los principales recursos minerales que están siendo explotados, especialmente en la región de la Sierra de los Carajás, incluyen oro, cobre, níquel, manganeso y, principalmente, hierro. Por otro lado, a pesar de albergar menos del 10% de las minas brasileñas, la Amazonia es responsable de cerca del 30% del valor global de la producción mineral del país. Las actividades depredadoras de miles de garimpeiros, dispersos en áreas enormes y poco pobladas, perjudican a los ríos amazónicos y a la floresta tropical. Por otro lado, la minería organizada, que opera a gran escala, propicia grandes ingresos, aunque ocupe un reducido espacio de terreno. El caso de la Floresta de Carajás (FLONA) es emblemático donde la minería organizada y sostenible ha protegido de la deforestación a toda el área, que permanece íntegramente preservada, mientras que el entorno de la región ha sido devastado por la agricultura y la ocupación humana.Bens minerais são imprescindíveis à humanidade desde os primórdios da civilização e recursos minerais serão sempre necessários, e em proporção crescente. A Amazônia, cerca da metade do território brasileiro, representa a última fronteira mineral importante do planeta. A região possui um potencial mineiro enorme, pouco aproveitado. Novos modelos para formação de depósitos minerais estão sendo testados, havendo possibilidades de no futuro vir a ser caracterizada uma nova província mineral produtora de cobre, molibdênio e ouro. Os principais recursos minerais que estão sendo explorados, especialmente na região da Serra dos Carajás, incluem ouro, cobre, níquel, manganês e, principalmente ferro. Por outro lado, apesar de abrigar menos de 10% das minas brasileiras, a Amazônia é responsável por cerca 30% do valor global da produção mineral do país. Atividades predatórias prejudicam os rios amazônicos e a floresta tropical, pela ação de milhares de garimpeiros, dispersos em áreas enormes, pouco povoadas. Por outro lado, a mineração organizada, que opera em grande escala, propicia grandes receitas, mesmo ocupando um reduzido espaço de terreno. O caso da Floresta de Carajás (FLONA) é emblemático em que a mineração organizada e sustentável protegeu do desmatamento toda a área, que permaneceu inteiramente preservada, enquanto que em seu entorno a floresta da região foi devastada pela agropecuária e pela ocupação humana.Mineral goods are indispensable to mankind since the beginnings of civilization and mineral resources will always be needed, and in increasing proportion. The Amazon, about half the Brazilian territory, represents the last important mineral border of the planet. The region has a huge mining potential, little used. New models for the formation of mineral deposits are being tested, with the possibility of a new mineral province producing copper, molybdenum and gold in the future. The main mineral resources being explored, especially in the Serra dos Carajás region, include gold, copper, nickel, manganese and, mainly, iron. On the other hand, although it holds less than 10% of the Brazilian mines, the Amazon is responsible for about 30% of the total value of the country’s mineral production. Predatory activities damage the Amazonian rivers and the tropical forest, by the action of thousands of garimpeiros, dispersed in huge, sparsely populated areas. On the other hand, organized mining, which operates on a large scale, provides large revenues, even if it occupies a small area of land. The case of Carajás Forest (FLONA) is an emblematic case in which organized and sustainable mining protected the whole area from deforestation, which remained entirely preserved, while in its surroundings the region was devastated by agriculture and human occupation

Strategies for Using Proximal Policy Optimization in Mobile Puzzle Games

While traditionally a labour intensive task, the testing of game content is progressively becoming more automated. Among the many directions in which this automation is taking shape, automatic play-testing is one of the most promising thanks also to advancements of many supervised and reinforcement learning (RL) algorithms. However these type of algorithms, while extremely powerful, often suffer in production environments due to issues with reliability and transparency in their training and usage. In this research work we are investigating and evaluating strategies to apply the popular RL method Proximal Policy Optimization (PPO) in a casual mobile puzzle game with a specific focus on improving its reliability in training and generalization during game playing. We have implemented and tested a number of different strategies against a real-world mobile puzzle game (Lily's Garden from Tactile Games). We isolated the conditions that lead to a failure in either training or generalization during testing and we identified a few strategies to ensure a more stable behaviour of the algorithm in this game genre.Comment: 10 pages, 8 figures, to be published in 2020 Foundations of Digital Games conferenc

Comparison of two analysis methods for nuclear reaction measurements of 12C +12C interactions at 95 MeV/u for hadrontherapy

During therapeutic treatment with heavier ions like carbon, the beam undergoes nuclear fragmentation and secondary light charged particles, in particular protons and alpha particles, are produced. To estimate the dose deposited into the tumors and the surrounding healthy tissues, the accuracy must be higher than ($\pm$3% and$\pm$1 mm). Therefore, measurements are performed to determine the double differential cross section for different reactions. In this paper, the analysis of data from 12C +12C reactions at 95 MeV/u are presented. The emitted particles are detected with \DeltaEthin-\DeltaEthick-E telescopes made of a stack of two silicon detectors and a CsI crystal. Two different methods are used to identify the particles. One is based on graphical cuts onto the \DeltaE-E maps, the second is based on the so-called KaliVeda method using a functional description of \DeltaE versus E. The results of the two methods will be presented in this paper as well as the comparison between both

Learning to Communicate: A Machine Learning Framework for Heterogeneous Multi-Agent Robotic Systems

We present a machine learning framework for multi-agent systems to learn both the optimal policy for maximizing the rewards and the encoding of the high dimensional visual observation. The encoding is useful for sharing local visual observations with other agents under communication resource constraints. The actor-encoder encodes the raw images and chooses an action based on local observations and messages sent by the other agents. The machine learning agent generates not only an actuator command to the physical device, but also a communication message to the other agents. We formulate a reinforcement learning problem, which extends the action space to consider the communication action as well. The feasibility of the reinforcement learning framework is demonstrated using a 3D simulation environment with two collaborating agents. The environment provides realistic visual observations to be used and shared between the two agents.Comment: AIAA SciTech 201

Variabilidad fenotípica inter e intra poblacional de Lippia integrifolia (Verbenaceae) y su situación natural en el centro-oeste de Argentina

The species Lippia integrifolia is an aromatic, sub-woody shrub, distributed from Northwest and Central Argentina to Bolivia. It is among the most important native aromatic species. It presents medicinal properties, some of which have been scientifically proven. As an alternative to harvesting, the process of domestication of the species was initiated. The objective of this work was to assess the phenotypic variability based on botanical-taxonomic and morpho-agronomic descriptors and the use of indicators to evaluate its natural situation in the west-center of Argentina. We worked in five wild populations, registering morphological variables, phenology, natural regeneration, herbivory and presence of diseases. L. integrifolia presents a wide morphological variability, which can be explained with three morphological descriptors. Natural regeneration´s rate is very low to zero, in four of the sites. The results obtained are of importance to make decisions related to the sustainable use in situ, and to begin a program of domestication of the species.La especie Lippia integrifolia es un arbusto aromático, sub-leñoso, distribuido desde el noroeste y centro de Argentina hasta Bolivia. Es una de las especies aromáticas nativas más importantes. Presenta propiedades medicinales, algunas de las cuales han sido científicamente probadas. Como alternativa a la cosecha, se inició el proceso de domesticación de la especie. El objetivo de este trabajo fue evaluar la variabilidad fenotípica basada en descriptores botánico taxonómicos y morfo-agronómicos y el uso de indicadores para evaluar su situación natural en el centro-oeste de Argentina. Trabajamos en cinco poblaciones silvestres, registrando variables morfológicas, fenología, regeneración natural, herviboría y presencia de enfermedades. L. integrifolia presenta una amplia variabilidad morfológica, que puede explicarse con tres descriptores morfológicos. La tasa de regeneración natural es muy baja a cero, en cuatro de los sitios. Los resultados obtenidos son importantes para tomar decisiones relacionadas con el uso sostenible in situ y para comenzar un programa de domesticación de la especie