Analysis of EPA Radionuclide Data from Water Samples on the Navajo Nation

The U.S. Environmental Protection Agency (EPA) has conducted risk assessments to quantify uranium exposure at inactive mining areas on the Navajo Nation. These evaluations include drinking water from domestic and agricultural sources dating back to the late 1990s because public water services were not entirely available in the mining districts at the time. This research reviews the radionuclide concentrations in the water samples determined by the EPA in 2000 to identify potential sources of water contamination. The inconsistencies of the radionuclide concentrations relative to their natural activities were initially observed. The concentrations of 234U and 210Pb tend to be higher than their parent nuclide in majority of the samples. The radionuclide distributions in the samples were compared using a non-parametric statistic test, the Mann-Whitney test. For instance, the results of the analysis for the distribution of 234U concentrations did not reflect the concentrations of 238U in water samples, and their behavior cannot be explained by the natural decay of 238U series (separated by decay of 234Th and 234Pa). Also, the water samples frequently contained higher or lower 235U ratio than its natural isotopic ratio of 0.72% ± 0.10%. The difference to the natural ratio can only be explained by errors in isotopic measurement, otherwise it would indicate that the mining areas were contaminated with enriched or depleted uranium. Based on these analyses, it is concluded that there may be errors in measurement of radionuclide or other sources of water contamination may exist in addition to the natural leaching processes (rain water) from mine tailings or solid material from mine areas transported by natural processes to groundwater and surface water

Paleogene continental Palynomorphs of the formations Chorrillo Chico and Agua Fresca, Pun- ta Prat, Magallanes, Chile

La sección paleógena de Punta Prat, Chile ubicada a 53°10´S - 71°20´O en el sur de la cuenca de Magallanes/Austral, incluye las Formaciones Chorrillo Chico y Agua Fresca. Ambas unidades contienen una asociación palinológica integrada por palinomorfos marinos y continentales que sugieren un ambiente de depositación marino con aporte de terrígenos. Los taxa continentales encontrados en las formaciones estudiadas reflejan un bosque desarrollado bajo un clima húmedo cálido a templado, dominado por Podocarpaceae, Proteaceae y Nothofagaceae acompañadas de abundantes helechos de las familias Schizaeaceae, Polypodiaceae y Dicksoniaceae. La relación de palinomorfos marinos/continentales indica una transgresión marina del Paleoceno al Eoceno Medio. Esta transgresión provocó la disminución de humedales hacia la parte superior de la columna, como lo muestra el bajo índice de palinomorfos paludales en la parte alta de la Formación Agua Fresca.The Paleogene section of Punta Prat, Chile is located at 53°10’S-71°20’W in southern Magallanes-Austral Basin, includes Chorrillo Chico and Agua Fresca Formations. Both units contain a palynological assemblage composed of marine and continental palynomorphs indicative of a marine depositional environment with terrigenous input. The continental taxa found in the studied formations reflect a forest developed under a humid warm to temperate climate, dominated by Podocarpaceae, Proteaceae and Nothofagaceae accompanied by abundant ferns belonging to the Schizaeaceae, Polypodiaceae and Dicksoniaceae families. The relationship of marine/continental palynomorphs indicates a marine transgression from the Paleocene to the Middle Eocene. This transgression caused the decline of wetlands towards the top of the column, as shown by the low rate of swamp inhabiting palynomorphs in the upper levels of the Agua Fresca Formation.Fil: Carrillo Berumen, Rosa. Centro de Investigación Científica y Educación Superior de Ensenada. Departamento de Geología; MéxicoFil: Quattrocchio, Mirta Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto Geológico del Sur; Argentina. Universidad Nacional del Sur; ArgentinaFil: Helenes, Javier. Centro de Investigación Científica y Educación Superior de Ensenada. Departamento de Geología; Méxic

Bio-electrosprayed human neural stem cells are viable and maintain their differentiation potential [version 2; peer review: 2 approved, 1 approved with reservations]

BACKGROUND: Bio-electrospray (BES) is a jet-based delivery system driven by an electric field that has the ability to form micro to nano-sized droplets. It holds great potential as a tissue engineering tool as it can be used to place cells into specific patterns. As the human central nervous system (CNS) cannot be studied in vivo at the cellular and molecular level, in vitro CNS models are needed. Human neural stem cells (hNSCs) are the CNS building block as they can generate both neurones and glial cells. METHODS: Here we assessed for the first time how hNSCs respond to BES. To this purpose, different hNSC lines were sprayed at 10 kV and their ability to survive, grow and differentiate was assessed at different time points. RESULTS: BES induced only a small and transient decrease in hNSC metabolic activity, from which the cells recovered by day 6, and no significant increase in cell death was observed, as assessed by flow cytometry. Furthermore, bio-electrosprayed hNSCs differentiated as efficiently as controls into neurones, astrocytes and oligodendrocytes, as shown by morphological, protein and gene expression analysis. CONCLUSIONS: This study highlights the robustness of hNSCs and identifies BES as a suitable technology that could be developed for the direct deposition of these cells in specific locations and configurations

Palinomorfos do Campaniano (Cretáceo Superior) da Bacia de Pelotas, Rio Grande do Sul: implicações bioestratigráficas e paleoambientais

This paper presents results of the palynological analyses carried out on core samples from the BP-01 well, drilled by PETROBRAS, offshore portion of the Pelotas Basin. They include seven samples from 4,480 to 4,487 m depth, with well preserved and varied palynological assemblages. Although not diversified, spores are the most abundant palynomorphs, dominated by species of Cicatricosisporites. On the other hand, cysts of dinoflagellates are less abundant but constitute the most diversified group, with 34 taxa, including 9 species previously unkown in the Brazilian marginal basins. Scarce palynoforaminifers, fungi, copepod eggs and prasinophycean acritarchs were also recorded. Dinocysts allow to assign this section to the Campanian (Upper Cretaceous). The palynological assemblages suggest a neritic environment, with relatively calm waters. A significant amount of spores, including several tetrads, indicates proximity to the continent. Furthermore, the biogeographic characteristics of certain cosmopolitan species of dinocysts confirm the interpretation of an open oceanic circulation pattern in the basin, linking waters from the northern and southern parts of the South Atlantic.Este trabalho apresenta os resultados da análise palinológica realizada em testemunhos de sondagem do poço BP-01 perfurado pela PETROBRAS na porção offshore da Bacia de Pelotas. Sete amostras entre 4.480 e 4.487 m de profundidade foram processadas, as quais revelaram uma associação palinológica bem preservada e diversificada. Os esporos, embora pouco diversificados, constituem o grupo de palinomorfos mais abundante, com destaque ao gênero Cicatricosiporites. Por outro lado, dinocistos, embora menos abundantes, apresentam maior diversidade, sendo representados por 34 táxons, incluindo o registro de 9 espécies inéditas para as bacias costeiras brasileiras. Palinoforaminíferos, ovos de copépodes, fungos e espécies de algas prasinofíceas são relativamente escassos. Em termos de idade, a análise da amplitude estratigráfica e dos níveis de extinção dos dinocistos registrados permitiu o posicionamento da seção no Campaniano (Cretáceo Superior). Os conjuntos palinológicos são indicativos de condições plataformais, em águas relativamente calmas. Contudo, a quantidade significativa de esporos, muitos dos quais em forma de tétrades, indica certa proximidade do continente. Alémdisso, é confirmado o padrão de ampla circulação oceânica instalado já no Campaniano na bacia, ligando águas setentrionais e austrais do Atlântico Sul, com base no registro de dinocistos com comportamento biogeográfico mais cosmopolita

ASSOCIAÇÕES PALINOLÓGICAS DO PALEÓGENO DA BACIA DE PELOTAS (POÇO BP-1, BRASIL) E SEU SIGNIFICADO ESTRATIGRÁFICO

Seis amostras de testemunhos de sondagem do Poço BP-1, Bacia de Pelotas, foram selecionadas para estudo palinológico, entre as profundidades 3.787,05 a 3.795,10 m, revelando rica associação de palinomorfos, dominada por cistos de dinoflagelados. Acritarcos, palinoforaminíferos, ovos de copépodes e miósporos ocorrem subordinadamente ao longo da seção, com baixa representatividade percentual. Espécies-guia de dinoflagelados foram utilizadas para fins de determinação bioestratigráfica da seção, permitindo o reconhecimento de associações posicionadas entre o limite Maastrichtiano – Daniano (Cretáceo – Paleógeno) e o Ypresiano (Eoceno). Os dados obtidos evidenciam que os sedimentos representativos do primeiro intervalo estão incorporados por retrabalhamento nos sedimentos ypresianos. O paleoambiente é interpretado como essencialmente marinho, dada a ampla diversidade de dinoflagelados registrada, em detrimento do baixo teor de palinomorfos de procedência continental. O apoio em outros dados bibliográficos existentes permitiu refinar as discussões acerca das prováveis idades envolvidas no intervalo estudado, e das flutuações do nível do mar relacionadas

Phylogeography of Supralittoral Rocky Intertidal Ligia Isopods in the Pacific Region from Central California to Central Mexico

Ligia isopods are widely distributed in the Pacific rocky intertidal shores from central California to central Mexico, including the Gulf of California. Yet, their biological characteristics restrict them to complete their life cycles in a very narrow range of the rocky intertidal supralittoral. Herein, we examine phylogeographic patterns of Ligia isopods from 122 localities between central California and central Mexico. We expect to find high levels of allopatric diversity. In addition, we expect the phylogeographic patterns to show signatures of past vicariant events that occurred in this geologically dynamic region.We sequenced two mitochondrial genes (Cytochrome Oxidase I and 16S ribosomal DNA). We conducted Maximum Likelihood and Bayesian phylogenetic analyses. We found many divergent clades that, in general, group according to geography. Some of the most striking features of the Ligia phylogeographic pattern include: (1) deep mid-peninsular phylogeographic breaks on the Pacific and Gulf sides of Baja peninsula; (2) within the Gulf lineages, the northern peninsula is most closely related to the northern mainland, while the southern peninsula is most closely related to the central-southern mainland; and, (3) the southernmost portion of the peninsula (Cape Region) is most closely related to the southernmost portion of mainland.Our results shed light on the phylogenetic relationships of Ligia populations in the study area. This study probably represents the finest-scale phylogeographic examination for any organism to date in this region. Presence of highly divergent lineages suggests multiple Ligia species exist in this region. The phylogeographic patterns of Ligia in the Gulf of California and Baja peninsula are incongruent with a widely accepted vicariant scenario among phylogeographers, but consistent with aspects of alternative geological hypotheses and phylo- and biogeographic patterns of several other taxa. Our findings contribute to the ongoing debate regarding the geological origin of this important biogeographic region

The life and scientific work of William R. Evitt (1923-2009)

Occasionally (and fortunately), circumstances and timing combine to allow an individual, almost singlehandedly, to generate a paradigm shift in his or her chosen field of inquiry. William R. (‘Bill’) Evitt (1923-2009) was such a person. During his career as a palaeontologist, Bill Evitt made lasting and profound contributions to the study of both dinoflagellates and trilobites. He had a distinguished, long and varied career, researching first trilobites and techniques in palaeontology before moving on to marine palynomorphs. Bill is undoubtedly best known for his work on dinoflagellates, especially their resting cysts. He worked at three major US universities and spent a highly significant period in the oil industry. Bill's early profound interest in the natural sciences was actively encouraged both by his parents and at school. His alma mater was Johns Hopkins University where, commencing in 1940, he studied chemistry and geology as an undergraduate. He quickly developed a strong vocation in the earth sciences, and became fascinated by the fossiliferous Lower Palaeozoic strata of the northwestern United States. Bill commenced a PhD project on silicified Middle Ordovician trilobites from Virginia in 1943. His doctoral research was interrupted by military service during World War II; Bill served as an aerial photograph interpreter in China in 1944 and 1945, and received the Bronze Star for his excellent work. Upon demobilisation from the US Army Air Force, he resumed work on his PhD and was given significant teaching duties at Johns Hopkins, which he thoroughly enjoyed. He accepted his first professional position, as an instructor in sedimentary geology, at the University of Rochester in late 1948. Here Bill supervised his first two graduate students, and shared a great cameraderie with a highly motivated student body which largely comprised World War II veterans. At Rochester, Bill continued his trilobite research, and was the editor of the Journal of Paleontology between 1953 and 1956. Seeking a new challenge, he joined the Carter Oil Company in Tulsa, Oklahoma, during 1956. This brought about an irrevocable realignment of his research interests from trilobites to marine palynology. He undertook basic research on aquatic palynomorphs in a very well-resourced laboratory under the direction of one of his most influential mentors, William S. ‘Bill’ Hoffmeister. Bill Evitt visited the influential European palynologists Georges Deflandre and Alfred Eisenack during late 1959 and, while in Tulsa, first developed several groundbreaking hypotheses. He soon realised that the distinctive morphology of certain fossil dinoflagellates, notably the archaeopyle, meant that they represent the resting cyst stage of the life cycle. The archaeopyle clearly allows the excystment of the cell contents, and comprises one or more plate areas. Bill also concluded that spine-bearing palynomorphs, then called hystrichospheres, could be divided into two groups. The largely Palaeozoic spine-bearing palynomorphs are of uncertain biological affinity, and these were termed acritarchs. Moreover, he determined that unequivocal dinoflagellate cysts are all Mesozoic or younger, and that the fossil record of dinoflagellates is highly selective. Bill was always an academic at heart and he joined Stanford University in 1962, where he remained until retiring in 1988. Bill enjoyed getting back into teaching after his six years in industry. During his 26-year tenure at Stanford, Bill continued to revolutionise our understanding of dinoflagellate cysts. He produced many highly influential papers and two major textbooks. The highlights include defining the acritarchs and comprehensively documenting the archaeopyle, together with highly detailed work on the morphology of Nannoceratopsis and Palaeoperidinium pyrophorum using the scanning electron microscope. Bill supervised 11 graduate students while at Stanford University. He organised the Penrose Conference on Modern and Fossil Dinoflagellates in 1978, which was so successful that similar meetings have been held about every four years since that inaugural symposium. Bill also taught many short courses on dinoflagellate cysts aimed at the professional community. Unlike many eminent geologists, Bill actually retired from actively working in the earth sciences. His full retirement was in 1988; after this he worked on only a small number of dinoflagellate cyst projects, including an extensive paper on the genus Palaeoperidinium