Synthesis dataset of physical and ecosystem properties from pan-arctic wetland sites using peat core analysis

Permafrost dynamics play an important role in high-latitude peatland carbon balance and are key to understanding the future response of soil carbon stocks. Permafrost aggradation can control the magnitude of the carbon feedback in peatlands through effects on peat properties. We compiled peatland plant macrofossil records for the northern permafrost zone (515 cores from 280 sites) and classified samples by vegetation type and environmental class (fen, bog, tundra and boreal permafrost, thawed permafrost). We examined differences in peat properties (bulk density, carbon (C), nitrogen (N) and organic matter content, C/N ratio) and C accumulation rates among vegetation types and environmental classes.

Four-leg converters with improved common current sharing and selective voltage-quality enhancement for islanded microgrids

Four-leg dc-ac power converters are widely used for the power grids to manage grid voltage unbalance caused by the interconnection of single-phase or three-phase unbalanced loads. These converters can further be connected in parallel to increase the overall power rating. The control of these converters poses a particular challenge if they are placed far apart with no links between them (e.g., in islanded microgrids). This challenge is studied in this paper with each four-leg converter designed to have improved common current sharing and selective voltage-quality enhancement. The common current sharing, including zero sequence component, is necessary since loads are spread over the microgrid and they are hence the common responsibility of all converters. The voltage-quality enhancement consideration should however be more selective since different loads have different sensitivity levels towards voltage disturbances. Converters connected to the more sensitive load buses should therefore be selectively triggered for compensation when voltage unbalances at their protected buses exceed the predefined thresholds. The proposed scheme is therefore different from conventional centralized schemes protecting only a common bus. Simulation and experimental results obtained have verified the effectiveness of the proposed scheme when applied to a four-wire islanded microgrid.

Calcium carbonate global LGM Burial rate data

Global databases of calcium carbonate concentrations and mass accumulation rates in Holocene and last glacial maximum sediments were used to estimate the deep-sea sedimentary calcium carbonate burial rate during these two time intervals. Sparse calcite mass accumulation rate data were extrapolated across regions of varying calcium carbonate concentration using a gridded map of calcium carbonate concentrations and the assumption that accumulation of noncarbonate material is uncorrelated with calcite concentration within some geographical region. Mean noncarbonate accumulation rates were estimated within each of nine regions, determined by the distribution and nature of the accumulation rate data. For core-top sediments the regions of reasonable data coverage encompass 67% of the high-calcite (>75%) sediments globally, and within these regions we estimate an accumulation rate of 55.9 ± 3.6 x 10**11 mol/yr. The same regions cover 48% of glacial high-CaCO3 sediments (the smaller fraction is due to a shift of calcite deposition to the poorly sampled South Pacific) and total 44.1 ± 6.0 x 10**11 mol/yr. Projecting both estimates to 100 % coverage yields accumulation estimates of 8.3 x 10**12 mol/yr today and 9.2 x 10**12 mol/yr during glacial time. This is little better than a guess given the incomplete data coverage, but it suggests that glacial deep sea calcite burial rate was probably not considerably faster than today in spite of a presumed decrease in shallow water burial during glacial time.

Pollen and non-pollen palynomorphs counting data from Borsteler Moor (Germany)

In order to reconstruct regional vegetation changes and local conditions during the fen-bog transition in the Borsteler Moor (northwestern Germany), a sediment core covering the period between 7.1 and 4.5 cal kyrs BP was palynologically in vestigated. The pollen diagram demonstrates the dominance of oak forests and a gradual replacement of trees by raised bog vegetation with the wetter conditions in the Late Atlantic. At ~ 6 cal kyrs BP, the non-pollen palynomorphs (NPP) demonstrate the succession from mesotrophic conditions, clearly indicated by a number of fungal spore types, to oligotrophic conditions, indicated by Sphagnum spores, Bryophytomyces sphagni, and testate amoebae Amphitrema, Assulina and Arcella, etc. Four relatively dry phases during the transition from fen to bog are clearly indicated by the dominance of Calluna and associated fungi as well as by the increase of microcharcoal. Several new NPP types are described and known NPP types are identified. All NPP are discussed in the context of their palaeoecological indicator values.

Geological reference standards (JLK-1,JSD-1, JSD-2, JSD-3,JMS-1, JMS-2) measured by Itrax-XRF core scanner in different exposure times

X-ray fluorescence (XRF) core-scanning is a fast and nondestructive technique to assess elemental variations of unprocessed sediments. However, although the exposure time of XRF-scanning directly affects the scanning counts and total measurement time, only a few studies have considered the influence of exposure time during the scan. How to select an optimal exposure time to achieve reliable results and reduce the total measurement time is an important issue. To address this question, six geological reference materials from the Geological Survey of Japan (JLK-1, JMS-1, JMS-2, JSD-1, JSD-2, and JSD-3) were scanned by the Itrax-XRF core scanner using the Mo- and the Cr-tube with different exposure times to allow a comparison of scanning counts with absolute concentrations. The regression lines and correlation coefficients of elements that are generally used in paleoenvironmental studies were examined for the different exposure times and X-ray tubes. The results show that for those elements with relatively high concentrations or high detectability, the correlation coefficients are higher than 0.90 for all exposure times. In contrast, for the low detectability or low concentration elements, the correlation coefficients are relatively low, and improve little with increased exposure time. Therefore, we suggest that the influence of different exposure times is insignificant for the accuracy of the measurements. Thus, caution must be taken when interpreting the results of elements with low detectability, even when the exposure times are long and scanning counts are reasonably high.

Pollen records of five sediment cores from northern Germany

Within a larger program research work is being done on the history of settlement and landscape of the 'Siedlungskammer' Flögeln and the adjacent area. The 'Siedlungskammer' consists of an isolated pleistocene sand ground (Geest-island) surroundet by bogs. Starting from the edge of the Geest, near which large-scale archaeological excavations are carried out, three raised bog profiles were taken at 300, 500 and 4000 m off the prehistoric settlement. They were investigated by means of pollen analysis, and reflect in a decreasing way the activities of man on the Geestisland. Another pollen diagram from the nearby fen peat was worked out for comparison. At the same time it helped to date back a prehistoric sand path to the Roman period. The pollen diagrams cover the vegetational history without gaps from the early Atlantic period to modern times. The vegetation was decisively determined by the poor soils of this area. T'he pollen diagrams give evidence of the activity of settlers since the Neolithic age, with some gaps in the beginning, but later continuously from the middle of the Bronze age until the early migration period. The influence of the nearby settlement, which existed from the Birth of Christ to the 4/5th century, comes out distinctly. Among the cereals which were then cultivated here, there also was rye, at least in the 4/5th century, but most probably already during the Roman period. Besides that people cultivated barley, oats, and flax. The settlement break during the so-called dark ages between the 4/5th century and the time about 800 A.D. was confirmed by pollen analysis. During this time the area was once more covered by forests. The fluctuations of man's activities during the late Middle Ages and modern times, as they are made visible by pollen analysis, correspond to historically wellknown developments.

Procesos migratorios: conceptos, fuentes y metodologías de análisis

Seminario Formativo del Programa de Doctorado Islas Atlánticas. Línea de investigación 1: Retos de la investigación en las dinámicas históricas y sociales del mundo atlántico, 2 y 3 de junio de 2016. Coordinado por Santiago de Luxán Meléndez. Aula Máster de la Escuela de Arquitectura de la Universidad de Las Palmas de Gran Canaria.

Procesos migratorios en Azores y Madeira

Seminario Formativo del Programa de Doctorado Islas Atlánticas. Línea de investigación 1: Retos de la investigación en las dinámicas históricas y sociales del mundo atlántico, 2 y 3 de junio de 2016. Coordinado por Santiago de Luxán Meléndez. Aula Máster de la Escuela de Arquitectura de la Universidad de Las Palmas de Gran Canaria.

Promoção da saúde e trabalho: um ensaio analítico

CAVALCANTE,Cleonice Andréa Alves, NÓBREGA, Jussara Azevedo Bezerra da, ENDERS,Bertha Cruz, MEDERIROS, Soraya Maria de. Promoção da saúde e trabalho: um ensaio analítico. Revista Eletrônica de Enfermagem. v.10,n.1 p.241-248.2008. Disponível em :fen.ufg.br/revista/v10/n1/v10n1a23.htm>.

Patrimonio arqueológico de las Islas Canarias

Los paisajes insulares canarios han estado sometidos a transformaciones que, en los tres últimos milenios se han debido, por un lado, a razones estrictamente naturales tales como emisiones lávicas y piroclásticas y por otro a causas antrópicas vinculadas con las prácticas agrícolas y ganaderas desarrolladas a partir de la primera colonización humana. Por lo que a esto último se refiere, en torno al cambio de Era hemos detectado en la isla de Lanzarote una notable degradación del medio asociada a un fenómeno de intensificación económica basada en actividades ganaderas. Desde la perspectiva metodológica se han utilizado datos geo-arqueológicos derivados de intervenciones arqueológicas y análisis sedimentológicos y polínicos efectuados en diferentes yacimientos de Lanzarote datados entre los siglos X a.C. y XIV d.C.

O que tenho a ver com isso? aula-vivência sobre violência contra crianças e adolescentes

A violência constitui hoje a principal causa de morte em crianças de 5 a 19 anos, o que tem imposto aos profissionais de saúde um olhar mais atento a estas questões, bem como uma formação que busque compreender este fenômeno sobre os vários prismas que a circunscreve. O objetivo deste artigo é relatar a experiência vivenciada com alunos do curso de Graduação em Enfermagem da Universidade Federal do Rio Grande do Norte numa aula-vivência sobre esta temática. A aula foi baseada numa prática pedagógica de ação reflexiva. Desenvolveu-se a partir da integração dos conteúdos teóricos e práticos, articulando-os com temas sociais, políticos e econômicos. A aula foi dividida em três momentos: um momento de sensibilização; um segundo momento onde foi apresentado e discutido o arcabouço teórico, científico e legal que envolve o tema; e um terceiro, que visou estimular uma reflexão sobre a realidade vivenciada nos serviços de saúde por profissionais que atuam diante de situações de violência. Nos três momentos da aula pudemos proporcionar ao aluno a inquietação e a reflexão necessárias para pensarmos sobre a violência em toda a sua complexidade, pluricausalidade e com toda a carga de preconceito em que esta se encontra envolvida