715 research outputs found
A microbe-bryozoan reef from the middle Visean of the Namur Syncline (Enginoul quarry)
A microbe-bryozoan patch-reef was temporarily exposed in the Lives Formation (middle Visean) at the Engihoul Quarry, southern limb of the Namur syncline. It developed within the Corphalie Member during the transition from bioclastic to stromatolitic facies. Reef formation is the result of a complex meshwork of calcified microbes, which formed complex layers which resemble “Osagia”-biocenose and individual columnar aggregates, fenestellid bryozoans, and early cements. Reef growth began on a hard-substrate provided by brachiopods and microbial crusts. Brachiopods (Composita sp.) are locally abundant in the reef facies, and contributed substantial firm ground for encrustation. Reef growth was controlled mainly by the abundance of fenestellid bryozoans. Their presence indicates reef formation during normal marine conditions. The reef developed in a high-energy area of the inner shelf. Reef growth probably stopped with the establishment of a peloidal mudstone facies, eventually indicating hypersaline conditions. The Engihoul reef is similar to Bomel reefs (also in the Lives Formation). All are the same age and developed in the transitional phase of the Corphalie Member, but minor differences in the individual reef fauna occur. The transitional phase of the Corphalie Member is an important horizon for reef formation with clear independence from other reef forming episodes within the Belgian Dinantian succession
Proceedings of the XIth International Symposium on Fossil Cnidaria and Porifera, Liege, Belgium, August 19-29, 2011: Preface
peer reviewe
Late Viséan to Early Serpukhovian Rugose Corals from the Yashui Section, Guizhou, South China
Abundant rugose corals are recorded in the Yashui Section in Huishui County of Central Guizhou, South China. The section is mainly composed of light-coloured bioclastic limestone with intercalations of some beds of dolomitized limestone and punctuated by a certain number of unconformities. Totally 20 species belonging to 13 genera are recognized. The composition of the fauna shows resemblance to the Western European faunas of latest Viséan to early Serpukhovian age. Many well-known European taxa such as Dibunophyllum bipartitum, Palaeosmilia murchisoni, Lithostrotion decipiens, Siphonodendron pauciradiale and Aulina rotiformis appear in Yashui, but with different stratigraphic ranges. There are also some endemic taxa such as Arachnolasma sinense, Yuanophyllum kansuense, Kueichouphyllum sinense and Stylostrotion petalaxoidae which can be used for correlations throughout South China. The coral diversity of the Yashui section shows: (1) a diversity decrease in the uppermost part of the Viséan, and (2) a poorly renewed fauna in the Serpukhovian, which is the similar pattern recorded in Palaeotethys. Therefore, a coral based biostratigraphic succession to separate the early Serpukhovian from latest Viséan is difficult to establish. Among the 20 species, 18 are described and illustrated, including 2 in open nomenclature. Two species are omitted from the description due to their bad preservation
Исследование физико-химических свойств комплексных гетероциклических соединений меди методом вольтамперометрии
Lectin prospecting in Colombian Labiatae. A systematic-ecological approach. - II
This is the second study of lectin and mucilage detection in Labiatae nutlets from
Colombia. It was carried out on 31 taxa belonging to 7 genera in which no previous
studies have been carried out in this field. A differential response was observed
in the group of genera and species studied in terms of mucilage presence as well
as lectin activity which consistently increased following extract treatment with
Pectinex. Lectin activity was detected in 28 species, being important (greater than
60% activity) in at least 75% of them. Genera such as Hyptis, Scutellaria, Aegiphila
and Lepechinia, whilst not presenting mucilage, did present lectin activity, having
high activity in most cases. By contrast, Salvia (in all sections studied) presented
mucilage and important lectin activity.Este es el segundo estudio sobre la presencia de mucílagos y lectinas en núculas
de Labiadas colombianas. Se llevó a cabo en 31 taxones, pertenecientes a siete
géneros, sobre los cuales no se disponía de información en este campo. Se observó
una respuesta diferencial en los géneros y especies en lo relativo a la presencia
de mucílago y a la actividad de lectina que se incrementó de manera consistente
después de tratar los extractos con Pectinex. Se detectó actividad de lectina en 28
especies, siendo muy importante (mayor del 60%) en al menos 75% de ellas. Aunque
los géneros Hyptis, Scutellaria, Aegiphila y Lepechinia no presentaron mucílago,
su actividad de la lectina fue alta. Por el contrario Salvia (en todas las secciones
estudiadas) presentó mucílago y una actividad importante de lectina.Peer reviewe
Corporate Hedging and Shareholder Value
According to financial theory, corporate hedging can increase shareholder value in the presence of capital market imperfections such as direct and indirect costs of financial distress, costly external financing, and taxes. This paper presents a comprehensive review of the extensive existing empirical literature that has tested these theories, documenting overall mixed empirical support for rationales of hedging with derivatives at the firm level. While various empirical challenges and limitations advise some caution with regard to the interpretation of the existing evidence, the results are, however, consistent with derivatives use being just one part of a broader financial strategy that considers the type and level of financial risks, the availability of risk-management tools, and the operating environment of the firm. In particular, recent evidence suggests that derivatives use is related to debt levels and maturity, dividend policy, holdings of liquid assets, and the degree of operating hedging. Moreover, corporations do not just use financial derivatives, but rely heavily on pass-through, operational hedging, and foreign currency debt to manage financial risk
Long-term exposure to fine particulate matter, lung function and cognitive performance:A prospective Dutch cohort study on the underlying routes
Background Exposure to fine particulate matter and black carbon is related to cognitive impairment and poor lung function, but less is known about the routes taken by different types of air pollutants to affect cognition. Objectives We tested two possible routes of fine particulate matter (PM2.5) and black carbon (BC) in impairing cognition, and evaluated their importance: a direct route over the olfactory nerve or the blood stream, and an indirect route over the lung. Methods We used longitudinal observational data for 31232 people aged 18+ from 2006 to 2015 from the Dutch Lifelines cohort study. By linking current and past home addresses to air pollution exposure data from ELAPSE, long-term average exposure (≥ ten years) to PM2.5 and BC was calculated. Lung function was assessed by spirometry and Global Initiative (GLI) z-scores of forced expiratory volume in 1s (FEV1) and forced vital capacity (FVC) were calculated. Cognitive performance was measured by cognitive processing time (CPT) assessed by the Cogstate Brief Battery. Linear structural equation modeling was performed to test the direct/indirect associations. Results Higher exposure to PM2.5 but not BC was directly related to higher CPT and thus slower cognitive processing speed [18.33 (×10−3) SD above the mean (95% CI: 6.84, 29.81)]. The direct association of PM2.5 constituted more than 97% of the total effect. Mediation by lung function was low for PM2.5 with a mediated proportion of 1.78% (FEV1) and 2.62% (FVC), but higher for BC (28.49% and 46.22% respectively). Discussion Our results emphasize the importance of the lung acting as a mediator in the relationship between both exposure to PM2.5 and BC, and cognitive performance. However, higher exposure to PM2.5 was mainly directly associated with worse cognitive performance, which emphasizes the health-relevance of fine particles due to their ability to reach vital organs directly
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