Geochemistry, isotopic ratios, granulometry and Uk'37 derived SST of cores obtained during Poseidon cruise POS287, off Portugal

Continental and marine conditions during the last millennium off Porto, Portugal (the southern pole of the North Atlantic Oscillation, NAO), are reconstructed from a sediment archive through a high-resolution multiproxy study and instrumental evidence. Results show multidecadal variability and sea surface temperatures (SSTs) that correlate well with previously published land and sea-based Northern Hemisphere temperature records, and appear to be responding to long-term solar insolation variability. Precipitation was negatively correlated with the NAO, whereas strong flooding events occurred at times of marked climate cooling (AD 1100-1150 and 1400-1470) and transitions in solar activity. AD 1850 marks a major shift in the phytoplankton community associated with a decoupling of d18O records of 3 planktonic foraminifera species. These changes are interpreted as a response to a reduction in the summer and/or annual upwelling and more frequent fall-winter upwelling-like events. This shift's coincidence with a decrease in SST and the increase in coherence between our data and the Atlantic Multidecadal Oscillation (AMO) confirms the connection of the upwelling variability to the North Atlantic Ocean's surface and thermohaline circulation on a decadal scale. The disappearance of this agreement between the AMO and our records beyond AD 1850 and its coincidence with the beginning of the recent rise in atmospheric CO2 supports the hypothesis of a strong anthropogenic effect on the last ~150 yr of the climate record. Furthermore, it raises an important question of the use of instrumental records as the sole calibration data set for climate reconstructions, as these may not provide the best analogue for climate beyond AD 1730.

Methane measurements in the Laptev Sea, Arctic Ocean

In der Wassersäule der Laptew See haben die Bildungs- und Verteilungsbedingungen vielfliltige Ursachen. Für die südliche Lapt ew See konnte eine Methananomalie innerhalb des Lenaausstrorns nachgewiesen werden, die im direkten Zusammenhang mit dem Flußwasser stehen muß. Mit den hohen Konzentrationen am Kontinentalhang ergab sich ein Hinweis auf eventuell vorhandene Gashydrate an der Sole eines zum Hang hin auskeilenden Permafrosts oder auf Gashydrate in den Sedimenten des Kontinentalhangs selbst. Ob es entlang der reliktisch vorhandenen, ehemaligen Flußläufe auf dem Schel f ebenfalls zu Entgasungen kommt, bleibt allerdings weiter unklar, da dieses Phänomen nicht beobachtet wurde oder die Anomalien nicht eindeutig diesem Prozeß zuzuordnen waren. Sicherlich ist die COz-Reduktion im Sediment in der Laptew See eine Hauptquelle für marines, bodennahes Methan. Die Ergebnisse. zeigen, daß dieser Bildungsprozeß vor allem für die küstennahen Bereiche wahrscheinlich ist. Dennoch gibt es auch Bereiche, wo die Zuordnung zu einer expliziten Methanquelle nicht eindeutig ist. Für eine genauere Bewertung der Herkunft der Gase sollten in künftigen Untersuchungen die Methankonzentrationen des Sediments einbezogen werden. Aber auch die Isotopensignaturen des Gases im Sediment können wertvolle Hinweise auf die Genese geben, vor allem wenn die Wasserstoffisotopie mituntersucht wird. Dies erscheint sinnvoll, da sich dur ch leichtes, bodennahes, Methan in der Wassersäule Hinweise auf biogene Bildungen ergaben, dieser Befund könnte durch weitere Untersuchungen präzisiert werden. Dies gilt aber auch für die CH4-Anomalien des OberfIächenwassers. Auch hier ergaben sich durch leicht KohIenstoffsignaturen Hinweise auf biogene in situ-Produktion. Mit detaillierteren Methankonzentrations- und d13C- CH4-Isotopenprofilen der Wassersäule könnte dieser Bildungspfad eindeutiger beschrieben werden. Es konnte ferner gezeigt werden, daß die Lapt ew See während der Sommermonate eine Quelle für atmosphärisches CI L darstellt. Das emittierte Gas geht neben vereinzelten Bodenquellen auch auf in situ-Produktion in der Wassersäule zurück. Abgesehen von der nördlichen Region geht das Methan bodennaher Anomalien innerhalb der Wassersäule sehr schnell zurück und nur ein kleiner Teil gelangt so schließlich in die Atmosphäre. Der während der ARK-XIV Expedition getestete Methansensor hat sich als ungeeignet für den Einsatz gemeinsam mit der CTD erwiesen. Es hat sich gezeigt, daß der Sensor unter diesen Bedingungen nicht genügend Zeit hat, um sein Meßsignal zu stabilisieren. Möglicherweise kann er aber in modifizierter For m und mit einer Kalibration für niedrigere Konzentrationsbereiche als stationäres Meßgerät eingesetzt werden. Für hohe CH4-Konzentrationen, wie man sie an Pockmarks antrifft, ist die Methansensormessung sicherlich auch jetzt schon eine geeignete Methode.

Seawater carbonate chemistry and calcification during experiments with a coral Madracis auretenra, 2010

Physiological data and models of coral calcification indicate that corals utilize a combination of seawater bicarbonate and (mainly) respiratory CO2 for calcification, not seawater carbonate. However, a number of investigators are attributing observed negative effects of experimental seawater acidification by CO2 or hydrochloric acid additions to a reduction in seawater carbonate ion concentration and thus aragonite saturation state. Thus, there is a discrepancy between the physiological and geochemical views of coral biomineralization. Furthermore, not all calcifying organisms respond negatively to decreased pH or saturation state. Together, these discrepancies suggest that other physiological mechanisms, such as a direct effect of reduced pH on calcium or bicarbonate ion transport and/or variable ability to regulate internal pH, are responsible for the variability in reported experimental effects of acidification on calcification. To distinguish the effects of pH, carbonate concentration and bicarbonate concentration on coral calcification, incubations were performed with the coral Madracis auretenra (= Madracis mirabilis sensu Wells, 1973) in modified seawater chemistries. Carbonate parameters were manipulated to isolate the effects of each parameter more effectively than in previous studies, with a total of six different chemistries. Among treatment differences were highly significant. The corals responded strongly to variation in bicarbonate concentration, but not consistently to carbonate concentration, aragonite saturation state or pH. Corals calcified at normal or elevated rates under low pH (7.6-7.8) when the seawater bicarbonate concentrations were above 1800 µm. Conversely, corals incubated at normal pH had low calcification rates if the bicarbonate concentration was lowered. These results demonstrate that coral responses to ocean acidification are more diverse than currently thought, and question the reliability of using carbonate concentration or aragonite saturation state as the sole predictor of the effects of ocean acidification on coral calcification.

Rock magentic investigations of ODP Site 162-983

We report natural remanent magnetization (NRM) directions and geomagnetic paleointensity proxies for part of the Matuyama Chron (0.9-2.2 Ma interval) from two sites located on sediment drifts in the Iceland Basin. At Ocean Drilling Program Sites 983 and 984, mean sedimentation rates in the late Matuyama Chron are 15.9 and 11.5 cm/kyr, respectively. For the older part of the record (>1.2 Ma), oxygen isotope data are too sparse to provide the sole basis for age model construction. The resemblance of the volume susceptibility record and a reference d18O record led us to match the two records to derive the age models. This match, based on Site 983/984 susceptibility, is consistent with available Site 983/984 benthic d18O data. Paleointensity proxies were derived from the slope of the NRM versus anhysteretic remanent magnetization plot for alternating field demagnetization in the 30-60 mT peak field range. Paleointensity lows correspond to polarity reversals at the limits of the Jaramillo, Olduvai, Cobb Mountain, and Réunion Subchrons and to seven excursions in NRM component directions. Magnetic excursions (defined here by virtual geomagnetic polar latitudes crossing the virtual geomagnetic equator) are observed at 932, 1048, 1115, 1190-1215 (Cobb Mountain Subchron), 1255, 1472-1480, 1567-1575 (Gilsa Subchron), and 1977 ka. The results indicate that geomagnetic directional excursions, associated with paleointensity minima, are a characteristic of the Matuyama Chron and probably of polarity chrons in general.

Grain size distributions of the Bossons glacier (France)

The study presented in this PhD memory aim at better define and quantify the present timeerosion processes in glacial and proglacial domain. The Glacier des Bossons, situated in theMont-Blanc massif (Haute-Savoie, France), is a good example of a natural and nonanthropizedsystem which allows us to study this topic. This glacier lies on two mainlithologies (the Mont-Blanc granite and the metamorphic bedrock) and this peculiarity is usedto determine the origin of the glacial sediments. The sediments were sampled at the glaciersurface and at the glacier sole and also in the subglacial streams in order to understand themechanisms of mechanical erosion and particle transportation in glacial domain. The study ofthe granulometric distribution and the origin of the sediments were performed by a lithologicanalysis at macro-scale (naked-eye) and a geochemical analysis at micro-scale (U-Pb datingof zircons). These analyses allowed specifying the characteristics of glacial erosion andtransport. (1) the supraglacial sediments derived from the erosion of the rocky valley sides aremainly coarse and the glacial transport does not mix these clasts with those derived from thesub-glacial erosion, except in the lower tongue; (2) the sub-glacial erosion rates areinhomogeneous, erosion under the temperate glacier (0.4-0.8 mm/yr) is at least sixteen timesmore efficient than the erosion under the cold glacier (0.025-0.05 mm/yr); (3) the sub-glacialsediments contain a silty and sandy fraction, resulting from processes of abrasion andcrushing, which is evacuated by sub-glacial streams. The high-resolution temporal acquisitionof hydro-sedimentary data during the 2010 melt season, between the May 5th and theSeptember 17th, allowed defining the seasonal behavior of the hydrologic and sedimentaryfluxes. The sediment exportation occurs mainly during the melt season therefore, quantify thesediment fluxes in the Bossons stream and measure regularly the topographic evolution of thefluvio-glacial system allows to perform a sedimentary balance of the erosion of glacial andnon-glacial domains. During the year 2010, about 3000 tons of sediments were eroded with430 tons settled on the fluvio-glacial system. By analyzing the evolution of suspendedparticulate matter concentrations in the Bossons stream upstream and downstream the fluvioglacialsystem, the part of glacial erosion and non-glacial denudation in the sedimentarybalance could be proportioned. The erosion during the stormy events of the uncoveredmoraines, confining the fluvio-glacial system of the Bossons stream, furnishes at least 59% ofthe sediments exported by the Bossons stream and glacial erosion (41% of the flux) istherefore less efficient comparatively. The long-term evolution of the glacial systems inperiod of global warming would show a sustained erosion of proglacial environments(mountain sides and moraines) recently exposed and therefore an increasing of the detritalfluxes. The Glacier des Bossons protects the summit of the Mont-Blanc, the differentialerosion between zones under the ice and non-glacial could lead to an increase of thedifference of altitude between valleys and summits.

Chemical and isotopic compositions of zircons from amphibolites of the Kamchatksky Cape Peninsula

The paper reports the first data on geochemistry and U-Pb SHRIMP geochronology of zircons from garnet amphibolites whose fragments are hosted by the sole of the ophiolite complex of the Kamchatsky Cape, eastern Kamchatka. The zircons compose homogeneous sampling, have relatively small sizes, are anhedral, have no oscillatory zoning, and possess practically no inclusions. Chemical and photoluminescent characteristics of the zircons testify to their metamorphic genesis. U-Pb SHRIMP dates of the zircons (81.4+/-9.6 Ma) indicate that metamorphism of the amphibolite complex took place in Campanian, Late Cretaceous. These dates seem to correspond to the peak of high-pressure metamorphism, which is thought to be related to origin of an ophiolite complex of the suprasubduction type and its uplift within the Kronotsky Island arc.

Pollen spectra and relative pollen productivity estimates for common taxa of the northern Siberian Arctic

Pollen productivity estimates (PPE) are used to quantitatively reconstruct variations in vegetation within a specific distance of the sampled pollen archive. Here, for the first time, PPEs from Siberia are presented. The study area (Khatanga region, Krasnoyarsk territory, Russia) is located in the Siberian Sub-arctic where Larixis the sole forest-line forming tree taxon. Pollen spectra from two different sedimentary environments, namely terrestrial mosses (n=16) and lakes (n=15, median radius ~100 m) and their surrounding vegetation were investigated to extract PPEs. Our results indicate some differences in pollen spectra between moss and lake pollen. Larix and Cyperaceae for example obtained higher representation in the lacustrine than in terrestrial moss samples. This highlights that in calibration studies modern and fossil dataset should be of similar sedimentary origin. The results of the Extended R-Value model were applied to assess the relevant source area of pollen (RSAP) and to calculate the PPEs for both datasets. As expected, the RSAP of the moss samples was very small (about 10 m) compared to the lacustrine samples (about 25 km). Calculation of PPEs for the six most common taxa yielded generally similar results for both datasets. Relative to Poaceae (reference taxon, PPE=1) Betula nana-type (PPEmoss: 1.8, PPElake: 1.8) and Alnusfruticosa-type (PPEmoss: 6.4, PPElake: 2.9) were overrepresented while Cyperaceae (PPEmoss: 0.5, PPElake: 0.1), Ericaceae (PPEmoss: 0.3, PPElake <0.01), Salix (PPEmoss: 0.03, PPElake <0.01) and Larix (PPEmoss <0.01, PPElake: 0.2) were under-represented in the pollen spectra compared to the vegetation in the RSAP. The estimation for the dominant tree in the region, Larixgmelinii, is the first published result for this species, but need to be considered very preliminary. The inferred sequence from over- to under-representation is mostly consistent with results from Europe; however, still the absolute values show some differences. Gathering vegetation data was limited by flowering season and low resolute satellite imagery and accessibility of the remote location of our study area. Therefore, our estimate may serve as first reference to strengthen future vegetation reconstructions in this climate-sensitive region.

Incentives Embedded in Institutions: The Case of Share Contracts in Ghanaian Cocoa Production

Providing price incentives to farmers is usually considered essential for agricultural development. Although such incentives are important, regarding price as the sole explanatory factor is far from satisfactory in understanding the complex realities of agricultural production in Africa. By analyzing the share contracts widely practiced in Ghana, this article argues that local institutions such as land tenure systems and agrarian contracts provide strong incentives and disincentives for agricultural production. Based on data derived from fieldwork in the 1990s, the study analyzes two types of share contracts and the incentive structures embedded in them. The analysis reveals that farmers' investment behavior needs to be understood in terms of both short-term incentive to increase yield and long-term incentive to strengthen land rights. The study concludes that the role of price incentives in agricultural production needs to be reconsidered by placing it in wider incentive structures embedded in local institutions.

A journey through the secret history of the Flying Geese Model

Economic development in East Asia is characterized by the sequential "take-off" of member countries. This multi-tiered economic development in East Asia is often termed the “Flying Geese” pattern of economic development. However, some authors argue that the traditional Flying Geese pattern is not applicable to some industries such as electronics. Here, Japan may no longer be the sole "leading goose", with "followers" such as China (now producing cutting-edge products) having "caught-up". Does this mean that the Flying Geese Model has become "obsolete" in the 21st century? The main objective of this paper is to clarify the two concepts of Flying Geese which now seem confused: (1) application of the pattern of economic development in one specific country, and (2) application of the pattern of economic development to multiple countries in sequence. This paper provides validity checks of Flying Geese Models after differentiating these two concepts more clearly

Physiological features of Schizosaccharomyces pombe of interest in the making of white wines

This work studies the physiology of Schizosaccharomyces pombe strain 938 in the production of white wine with high malic acid levels as the sole fermentative yeast, as well as in mixed and sequential fermentations with Saccharomyces cerevisiae Cru Blanc. The induction of controlled maloalcoholic fermentation through the use of Schizosaccharomyces spp. is now being viewed with much interest. The acetic, malic and pyruvic acid concentrations, relative density and pH of the musts were measured over the entire fermentation period. In all fermentations in which Schizo. pombe 938 was involved, nearly all the malic acid was consumed and moderate acetic concentrations produced. The urea content and alcohol level of these wines were notably lower than in those made with Sacch. cerevisiae Cru Blanc alone. The pyruvic acid concentration was significantly higher in Schizo. pombe fermentations. The sensorial properties of the different final wines varied widely.

Preclarissima [et] inestimabilis doctrine atq[ue] vtilitatis Diui Aurelij Augustini sermonu[m] opera.

Marca tip. de Berthold Rembolt en port. (Renouard, 961)

Preclarissima [et] inestimabilis doctrine atq[ue] vtilitatis Diui Aurelij Augustini sermonu[m] opera.

Marca tip. de Berthold Rembolt en port. (Renouard, 961)

In hoc volumine beati Bonaue[n]ture subiecta comprehenduntur : Oratio Octauiani in vitam beati Bonauenture ; Libellus de reductione artium ad theologiam ; Tractatus de paup[eri]tate [Christi] [con]tra mag[ist]r[u]m, vvilhelmum ; Tractatulus de quinq[ue] f

Impresor y año tomados del colofón

In hoc volumine beati Bonaue[n]ture subiecta comprehenduntur : Oratio Octauiani in vitam beati Bonauenture ; Libellus de reductione artium ad theologiam ; Tractatus de paup[eri]tate [Christi] [con]tra mag[ist]r[u]m, vvilhelmum ; Tractatulus de quinq[ue] f

Impresor y año tomados del colofón

Influence of the Second Flexural Mode on the Response of High-Speed Bridges

This paper deals with the assessment of the contribution of the second flexural mode to the dynamic behaviour of simply supported railway bridges. Alluding to the works of other authors, it is suggested in some references that the dynamic behaviour of simply supported bridges could be adequately represented taking into account only the contribution of the fundamental flexural mode. On the other hand, the European Rail Research Institute (ERRI) proposes that the second mode should also be included whenever the associated natural frequency is lower than 30 Hz]. This investigation endeavours to clarify the question as much as possible by establishing whether the maximum response of the bridge, in terms of displacements, accelerations and bending moments, can be computed accurately not taking account of the contribution of the second mode. To this end, a dimensionless formulation of the equations of motion of a simply supported beam traversed by a series of equally spaced moving loads is presented. This formulation brings to light the fundamental parameters governing the behaviour of the beam: damping ratio, dimensionless speed $ \alpha$=VT/L, and L/d ratio (L stands for the span of the beam, V for the speed of the train, T represents the fundamental period of the bridge and d symbolises the distance between consecutive loads). Assuming a damping ratio equal to 1%, which is a usual value for prestressed high-speed bridges, a parametric analysis is conducted over realistic ranges of values of $ \alpha$ and L/d. The results can be extended to any simply supported bridge subjected to a train of equally spaced loads in virtue of the so-called Similarity Formulae. The validity of these formulae can be derived from the dimensionless formulation mentioned above. In the parametric analysis the maximum response of the bridge is obtained for one thousand values of speed that cover the range from the fourth resonance of the first mode to the first resonance of the second mode. The response at twenty-one different locations along the span of the beam is compared in order to decide if the maximum can be accurately computed with the sole contribution of the fundamental mode.