Avaliação da sazonalidade e contaminação por elementos no desempenho do poliqueta Diopatra neapolitana da Ria de Aveiro

Estuaries are interface ecosystems that unite the continental and marine environments, receiving active biogeochemical contributions from the coast, rivers and coastal seas. As estuaries are a mixture of fresh and saltwater, they act as discharge zones and sources of pollutants. Ria de Aveiro is a good example of an ecologically active coastal system that over the years has suffered more from anthropogenic activities, such as agriculture and effluent discharge. Ria de Aveiro also contains a wide variety of species that live there. Metals are elements that naturally exist in nature, however, due to anthropogenic activities, these elements can contaminate the waters, due to discharges or alteration of their geochemistry. This phenomenon has negative impacts on marine life and becomes harmful at the food chain's upper levels. Polychaetes are usually the most abundant group in estuarine systems and are an important food source for species of various trophic levels. Some species are also of economic importance. Several studies have already been done with these organisms on the impacts of climate change and water contaminants, being known as sentinel organisms. Diopatra neapolitana is a species with great ecological relevance in the Ria de Aveiro and is widely used for the studies mentioned above, that is why we decided to use this organism to this study. This work has the main objective to understand how the seasonality impacts the bioaccumulation of elements in the polychaete D. neapolitana and determine how it responds to this type of contaminants through biochemical markers. For this, D. neapolitana organisms were harvested over the four seasons of the year, in 2018 and 2019 in five different locations of Ria de Aveiro. In general, the results obtained in this work demonstrated that Autumn was the season in which the sediments presented higher concentration of elements, mainly in the site Cale do Ouro. However, concerning tissue samples, Autumn and Summer were the seasons when organisms bioaccumulated more elements. These results also indicate that abiotic factors like temperature, salinity, pH, dissolved oxygen, fines content and organic matter influence the availability of the elements. Also, elements bioaccumulated differently in polychaete tissues fractions since insoluble fraction accumulated more elements than soluble fraction. Regarding antioxidant defenses, higher enzymatic activity was observed during Spring and Summer, mainly due to high temperatures and the bioaccumulation of elements. The metabolism-related parameters showed higher levels during Spring and Autumn also mainly due to elements bioaccumulation. Lipid damage was higher during the Winter, and this was mainly due to the physical and chemical characteristics of the sampling sites, such as salinity and temperature decrease.Os estuários são ecossistemas de interface que unem os ambientes continental e marinho, recebendo contribuições biogeoquímicas ativas da costa, rios e mares costeiros. Como os estuários são uma mistura de água doce e salgada, eles atuam como zonas de descarga e fontes de poluentes. A Ria de Aveiro é um bom exemplo de sistema costeiro ecologicamente ativo que ao longo dos anos tem sofrido mais com atividades antropogénicas, como a agricultura e a descarga de efluentes da indústria e também porque contém uma grande variedade de espécies que ali habitam. Os metais são elementos que existem na natureza por meio natural, porém, devido a atividades antropogénicas, estes elementos podem contaminar as águas, devido a descargas ou à alteração da geoquímica destes. Este fenómeno tem impactos negativos na vida marinha acabando por se tornarem prejudiciais nos níveis superiores da cadeia trófica. Os poliquetas são normalmente o grupo mais abundante em sistemas estuarinos e são uma importante fonte de alimento para espécies de vários níveis tróficos. Algumas espécies também têm importância económica. Muitos estudos já foram feitos com estes organismos sobre impactos das alterações climáticas e contaminantes das águas, sendo por isso também conhecidas como organismos sentinela. Diopatra neapolitana é uma espécie com grande relevância ecológica na Ria de Aveiro e é muito utilizada para os estudos mencionados anteriormente. Este trabalho tem como principal objetivo compreender como é que a sazonalidade tem impacto na bioacumulação de metais no poliqueta D. neapolitana e determinar de que forma é que esta espécie responde a este tipo de contaminantes, através de marcadores bioquímicos. Para isso, foram colhidos organismos de D. neapolitana ao longo das quatro estações do ano, em 2018 e 2019 em cinco locais diferentes da Ria de Aveiro. De forma geral, os resultados obtidos neste trabalho demonstraram que o outono foi a estação em que se observou uma maior concentração de elementos nos sedimentos, principalmente no local Cale do Ouro. No entanto, em relação às amostras de tecido, o outono e o verão foram as estações do ano em que os organismos acumularam mais elementos. Esses resultados também indicam que os fatores abióticos como a temperatura, salinidade, pH, oxigénio dissolvido, conteúdo em finos e matéria orgânica influenciam a disponibilidade dos elementos. Além disso, os elementos acumularam de forma diferente entre as frações nos tecidos do poliqueta, tendo-se observado uma maior bioacumulação de elementos na fração insolúvel. Em relação às defesas antioxidantes, foi observada maior atividade enzimática durante a primavera e o verão, principalmente devido às altas temperaturas e à bioacumulação de elementos. Os parâmetros relacionados com o metabolismo apresentaram níveis mais elevados na primavera e no outono também principalmente devido à bioacumulação de elementos. O dano lipídico foi maior durante o inverno e isso ocorreu principalmente devido às características físicas e químicas dos locais de amostragem, como a diminuição da salinidade e da temperatura.Mestrado em Biologia Aplicad

Analysis of intermittency in submillimeter radio and hard x-ray data during the impulsive phase of a solar flare

We present an analysis of intermittent processes occurring during the impulsive phase of the flare SOL2012-03-13, using hard X-rays and submillimeter radio data. Intermittency is a key characteristic in turbulent plasmas and has so far only been analyzed for hard X-ray data. Since in a typical flare the same accelerated electron population is believed to produce both hard X-rays and gyrosynchrotron radiation, we compare the two time profiles by searching for intermittency signatures. For this, we define a cross-wavelet power spectrum, which is used to obtain the local intermittency measure, or LIMLIM. When greater than three, the square LIMLIM coefficients indicate a local intermittent process. The LIM2LIM2 coefficient distribution in time and scale helps to identify avalanche or cascade energy release processes. We find two different and well-separated intermittent behaviors in the submillimeter data: for scales greater than 20 s, a broad distribution during the rising and maximum phases of the emission seems to favor a cascade process; for scales below 1 s, short pulses centered on the peak time are representative of avalanches. When applying the same analysis to hard X-rays, we find that only the scales above 10 s produce a distribution related to a cascade energy fragmentation. Our results suggest that different acceleration mechanisms are responsible for tens of keV and MeV energy ranges of electrons

A Supplemental computer-assisted intervention to prevent early reading difficulties in spanish learners: a randomised controlled trial

Difficulties implementing effective instruction for at-risk students arise from two challenges: evidence-based knowledge transfer and lack of economic resources. Computer-assisted programs can offer a suitable solution, providing quality instruction with low cost resources. Thirty first grade students with learning difficulties were identified and paired on at least four pretest reading measures (reading efficiency of monosyllabic and disyllabic items, words, pseudowords, and texts). Each pair was assigned to two different intervention programs: a computer-assisted instructional program (CAP) focused on developing phonological route versus to the Spanish public school assistance services (AS). Computer-assisted instruction consisted of four individual 12-15 minute sessions per week focused on syllable decoding plus a collective comprehension session per week of 1 hour. CAP was delivered by university students. The assistance services typically consisted of one hour per week, individually or in small groups, delivered by trained teachers. Both programs were applied during eleven weeks. 9 of 15 subjects from the AS condition showed resistance to treatment, while only 5 of 15 subjects were treatment resisters on the CAP condition.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

A burst with double radio spectrum observed up to 212 GHz

We study a solar flare that occurred on September 10, 2002, in active region NOAA 10105 starting around 14:52 UT and lasting approximately 5 minutes in the radio range. The event was classified as M2.9 in X-rays and 1N in H\alpha. Solar Submillimeter Telescope observations, in addition to microwave data give us a good spectral coverage between 1.415 and 212 GHz. We combine these data with ultraviolet images, hard and soft X-rays observations and full-disk magnetograms. Images obtained from Ramaty High Energy Solar Spectroscopic Imaging data are used to identify the locations of X-ray sources at different energies and to determine the X-ray spectrum, while ultra violet images allow us to characterize the coronal flaring region. The magnetic field evolution of the active region is analyzed using Michelson Doppler Imager magnetograms. The burst is detected at all available radio-frequencies. X-ray images (between 12 keV and 300 keV) reveal two compact sources and 212 GHz data, used to estimate the radio source position, show a single compact source displaced by 25" from one of the hard X-ray footpoints. We model the radio spectra using two homogeneous sources, and combine this analysis with that of hard X-rays to understand the dynamics of the particles. Relativistic particles, observed at radio wavelengths above 50 GHz, have an electron index evolving with the typical soft-hard-soft behaviour.Comment: Submitted to Solar Physics, 20 pages, 8 fugure

Observando la cromosfera solar en el infrarrojo

The solar chromosphere has historically been studied from spectral lines in the visible and UV, notably H{\alpha}, Ca ii, Mg ii and Ly{\alpha}. Observations at long UV wavelengths (304, 1600 and 1700 {\AA}) from space have been recently added. However, the chromosphere can also be studied in the infrared (IR), both in the continuum as in the lines. Studies in this spectral band, which by definition extends from 1 {\mu}m to 1 mm, are scarce and recent, and its advantages having been little explored. In this work we present a review of what has been done and detail how much can be done with ground-based instruments. Argentina has a set of unique telescopes for the observation of the chromosphere, some with more than 20 years of operation and in process of renovation, others recently installed and still some in development. The panorama is very encouraging and allows to anticipate a strong international cooperation with other ground and space facilities.Comment: Accepted in the Bolet\'in de la Asociaci\'on Argentina de Astronom\'ia, 2023. In Spanish. 7 pages, 8 figure

Submillimeter and X-ray observations of an X Class flare

The GOES X1.5 class flare that occurred on August 30,2002 at 1327:30 UT is one of the few events detected so far at submillimeter wavelengths. We present a detailed analysis of this flare combining radio observations from 1.5 to 212 GHz (an upper limit of the flux is also provided at 405 GHz) and X-ray. Although the observations of radio emission up to 212 GHz indicates that relativistic electrons with energies of a few MeV were accelerated, no significant hard X-ray emission was detected by RHESSI above ~ 250 keV. Images at 12--20 and 50--100 keV reveal a very compact, but resolved, source of about ~ 10" x 10". EUV TRACE images show a multi-kernel structure suggesting a complex (multipolar) magnetic topology. During the peak time the radio spectrum shows an extended flatness from ~ 7 to 35 GHz. Modeling the optically thin part of the radio spectrum as gyrosynchrotron emission we obtained the electron spectrum (spectral index delta, instantaneous number of emitting electrons). It is shown that in order to keep the expected X-ray emission from the same emitting electrons below the RHESSI background at 250 keV, a magnetic field above 500 G is necessary. On the other hand, the electron spectrum deduced from radio observations >= 50 GHz is harder than that deduced from ~ 70 - 250 keV X-ray data, meaning that there must exist a breaking energy around a few hundred keV. During the decay of the impulsive phase, a hardening of the X-ray spectrum is observed which is interpreted as a hardening of the electron distribution spectrum produced by the diffusion due to Coulomb collisions of the trapped electrons in a medium with an electron density of n_e ~ 3E10 - 5E10 cm-3.Comment: Accpeted in Astronomy & Astrophysics. 9 Pages, 6 Figures ADDED REFERENCE

Hß photometry for uvby standard stars

From 1984 to 1986, we made several observational campaigns at Calar Alto and La Palma Observator­ies using the uvby and ß photometric systems to monitor a selected sample of late-type variable stars. In this paper we present the ß values for 38 uvby standard stars to contribute to the uvby-ß calibration works on late-type stars. In the final discussion, the ß computed values are plotted against the Ström­gren b - y, m_1, and c_1 indices

Estimation of factors conditioning the acquisition of academic skills in Latin America in the presence of endogeneity

This article identifies the main determinants of skill acquisition in Latin America. Not having repeated a grade, sex, the number of books in the home and the mother’s education are defined as individual and family characteristics. In the case of school characteristics, the results are more heterogeneous between countries. The key factors seem to be attending a private school, the number of students per classroom, the quality of the educational materials available, and larger school size and autonomy. The characteristics of the schools explain most of the variability of the results, followed by family characteristics and then individual ones. School-based factors play a particularly crucial role in Argentina, Brazil and Costa Rica; family characteristics are very important in Chile, Colombia and Peru; and individual ones are important in Colombia and Mexico