Innate sensors for Gram-positive bacteria.

More than half of invasive bacterial infections are Gram-positive in origin. This class of bacteria has neither endotoxins nor an outer membrane, yet it generates some of the most powerful inflammatory responses known in medicine. Some recent seminal studies go a long way toward settling the controversies that surround the process by which Gram-positive bacterial surfaces trigger the human immune system. Although the components of the cell wall are now chemically defined in exquisite detail and the interaction with the toll-like receptor 2 pathway has been discovered, it is only very recently that definitive studies combining these advanced biochemical and cell biological tools have been carried out. It is these breakthrough studies that have finally confirmed the paradigm of innate sensors for Gram-positive bacteria.

Carbon isotope stratigraphy and carbonate production during the Early-Middle Jurassic: examples from the Umbria-Marche-Sabina Apennines (Central Italy)

The carbon isotopic signature of carbonates depends on secular variations of organic carbon and carbonate carbon production/burial rates. A decrease in carbonate productivity makes the organic/carbonate carbon ratio unstable up to the point that even minor variations in the organic carbon reservoirs can provoke carbon isotopic shifts. The delta(13)C positive shifts of the middle Carixian (early Pliensbachian) and the early Bajocian recorded in the Umbria-Marche-Sabina domain represent a good example of this mechanism. Both sedimentology and lithostratigraphy of pelagic platform-basin carbonate systems in this area show that important changes in the source of carbonates correspond to the observed isotopic shifts. The middle Carixian event is in fact well correlatable to the drastic reduction of benthic carbonate production on rift-related intrabasinal highs, which then became pelagic carbonate platforms. The early Bajocian event is concomitant with the beginning of a long hiatus on the pelagic carbonate platforms and with a drop of the biodiversity of calcareous organisms followed by the onset of biosiliceous sedimentation in basins. (C) 2002 Elsevier Science B.V. All rights reserved.

Pedotransfer functions to estimate water retention parameters of soils in northeastern Brazil

Pedotransfer functions (PTF) were developed to estimate the parameters (α, n, θr and θs) of the van Genuchten model (1980) to describe soil water retention curves. The data came from various sources, mainly from studies conducted by universities in Northeast Brazil, by the Brazilian Agricultural Research Corporation (Embrapa) and by a corporation for the development of the São Francisco and Parnaíba river basins (Codevasf), totaling 786 retention curves, which were divided into two data sets: 85 % for the development of PTFs, and 15 % for testing and validation, considered independent data. Aside from the development of general PTFs for all soils together, specific PTFs were developed for the soil classes Ultisols, Oxisols, Entisols, and Alfisols by multiple regression techniques, using a stepwise procedure (forward and backward) to select the best predictors. Two types of PTFs were developed: the first included all predictors (soil density, proportions of sand, silt, clay, and organic matter), and the second only the proportions of sand, silt and clay. The evaluation of adequacy of the PTFs was based on the correlation coefficient (R) and Willmott index (d). To evaluate the PTF for the moisture content at specific pressure heads, we used the root mean square error (RMSE). The PTF-predicted retention curve is relatively poor, except for the residual water content. The inclusion of organic matter as a PTF predictor improved the prediction of parameter a of van Genuchten. The performance of soil-class-specific PTFs was not better than of the general PTF. Except for the water content of saturated soil estimated by particle size distribution, the tested models for water content prediction at specific pressure heads proved satisfactory. Predictions of water content at pressure heads more negative than -0.6 m, using a PTF considering particle size distribution, are only slightly lower than those obtained by PTFs including bulk density and organic matter content.

Surface mapping, organic matter and water stocks in peatlands of the Serra do Espinhaço meridional - Brazil

Peatlands are soil environments that store carbon and large amounts of water, due to their composition (90 % water), low hydraulic conductivity and a sponge-like behavior. It is estimated that peat bogs cover approximately 4.2 % of the Earth's surface and stock 28.4 % of the soil carbon of the planet. Approximately 612 000 ha of peatlands have been mapped in Brazil, but the peat bogs in the Serra do Espinhaço Meridional (SdEM) were not included. The objective of this study was to map the peat bogs of the northern part of the SdEM and estimate the organic matter pools and water volume they stock. The peat bogs were pre-identified and mapped by GIS and remote sensing techniques, using ArcGIS 9.3, ENVI 4.5 and GPS Track Maker Pro software and the maps validated in the field. Six peat bogs were mapped in detail (1:20,000 and 1:5,000) by transects spaced 100 m and each transect were determined every 20 m, the UTM (Universal Transverse Mercator) coordinates, depth and samples collected for characterization and determination of organic matter, according to the Brazilian System of Soil Classification. In the northern part of SdEM, 14,287.55 ha of peatlands were mapped, distributed over 1,180,109 ha, representing 1.2 % of the total area. These peatlands have an average volume of 170,021,845.00 m³ and stock 6,120,167 t (428.36 t ha-1) of organic matter and 142,138,262 m³ (9,948 m³ ha-1) of water. In the peat bogs of the Serra do Espinhaço Meridional, advanced stages of decomposing (sapric) organic matter predominate, followed by the intermediate stage (hemic). The vertical growth rate of the peatlands ranged between 0.04 and 0.43 mm year-1, while the carbon accumulation rate varied between 6.59 and 37.66 g m-2 year-1. The peat bogs of the SdEM contain the headwaters of important water bodies in the basins of the Jequitinhonha and San Francisco Rivers and store large amounts of organic carbon and water, which is the reason why the protection and preservation of these soil environments is such an urgent and increasing need.

Evolution of a Ladinian (Middle Triassic) intraplatform basin : stratigraphy, microfacies and palaeoecology of the Meride Limestone (Monte San Giorgio, Canton Ticino, Southern Switzerland)

The Monte San Giorgio (Southern Alps, Ticino, Switzerland) is the most important locality in the world for vertebrates dating back to the Middle Triassic. For this reason it was registered in 2003 as a UNESCO World Heritage Site. One of the objectives of this doctoral thesis was to fill some of the cognitive gaps regarding the Ladinian succession, including in particular the San Giorgio Dolomite and the Meride Limestone. In order to achieve this, the entire succession, more than 600 metres thick, was measured and sampled. Biostratigraphic research based on new finds of fossil invertebrates and microfossils and on the palynological analysis of the entire section was integrated with single-zircon U-Pb dating of volcanic ash layers intercalated in the carbonate succession. This enabled a redefinition of the bio-chronostratigraphic and geochronologic framework of the succession, which encompasses a significantly shorter time interval than previously held. The Ladinian section extends from the E. curionii Ammonoid Zone (Early Fassanian) to the P. archelaus Ammonoid Zone (Early Longobardian). The age of the classic fossiliferous levels of the Meride Limestone, rich in organic matter and containing vertebrate fossils which are known all over the world, was defined in both biostratigraphic and geochronologic terms. The presumed stratigraphie significance of the pachypleurosaurid reptiles found in such levels is called into question by new finds. These fossiliferous horizons were found to correspond to the main volcanoclastic intervals of the Buchenstein Formation (Middle and Upper Pietra Verde). Thus, a correlation with the Bagolino Section (Italy) containing the GSSP for the base of the Ladinian was proposed. Bulk sedimentation rates in the studied succession average 200 m/Myr and therefore prove to be 20 times higher than those of the South-Alpine pelagic basins. These values express high carbonate productivity from the surrounding platforms on one hand, and on the other a marked subsidence of the basin. Only in the intervals consisting of laminated limestones did the sedimentation rates drop to average values of around 30 m/Myr. The distribution of organic and inorganic facies appears to be the consequence of relative variations in sea-level. The laminated and organic-matter- rich intervals of the Meride Limestone are linked to a relative sea-level drop which favoured dysoxic to anoxic bottom-water conditions, coupled with an increase in runoff, perhaps due to recurrent explosive volcanic activity. The transient development under dysoxic conditions of monospecific benthic meio-/macrofaunas was documented. Organic matter suggests a predominant origin due to benthic bacterial activity, as can be witnessed in alveolar structures typical of exopolymeric substances secreted by bacteria within microbial mats. A microbial contribution to the carbonate (peloidal) precipitation was documented. The protective effect exerted by these microbial mats is also indicated as the main taphonomic factor contributing to the excellent preservation of vertebrate fossils. A radiolarian assemblage discovered in the lower part of the section (earliest Ladinian, E. curionii Zone) suggests the transient existence of open-marine but not deep-water connections with the tethyan pelagic basins. It shows marked similarities to the faunas typical of the late Anisian, suggesting therefore a low resolution power provided by radiolarian biostratigraphy in recognizing the Anisian/Ladinian boundary. The present thesis describes a new species of conifer (Elatocladus cassinae), a new species of insect (Dasyleptus triassicus) and seven new species of radiolarians (Eptingium danieli, Eptingium neriae, Parentactinosphaera eoladinica, Sepsagon ticinensis, Sepsagon? valporinae, Novamuria wirzi and Pessagnollum? hexaspinosum). In addition, following revision of the type material of already existent taxa, four new genera of radiolarians are introduced: Bernoulliella, Eohexastylus, Ticinosphaera and Lahmosphaera.

New stratigraphic data from the Lower Penninic between the Adula nappe and the Gotthard massif and consequences for the tectonics and the paleogeography of the Central Alps

New stratigraphic data along a profile from the Helvetic Gotthard Massif to the remnants of the North Penninic Basin in eastern Ticino and Graubunden are presented. The stratigraphic record together with existing geochemical and structural data, motivate a new interpretation of the fossil European distal margin. We introduce a new group of Triassic facies, the North-Penninic-Triassic (NPT), which is characterised by the Ladinian "dolomie bicolori". The NPT was located in-between the Briançonnais carbonate platform and the Helvetic lands. The observed horizontal transition, coupled with the stratigraphic superposition of an Helvetic Liassic on a Briaçonnais Triassic in the Luzzone-Terri nappe, links, prior to Jurassic rifting, the Briançonnais paleogeographic domain at the Helvetic Margin, south of the Gotthard. Our observations suggest that the Jurassic rifting separated the Briançonnais domain from the Helvetic margin by complex and protracted extension. The syn-rift stratigraphic record in the Adula nappe and surroundings suggests the presence of a diffuse rising area with only moderately subsiding basins above a thinned continental and proto-oceanic crust. Strong subsidence occurred in a second phase following protracted extension and the resulting delamination of the rising area. The stratigraphic coherency in the Adula's Mesozoic questions the idea of a lithospheric mélange in the eclogitic Adula nappe, which is more likely to be a coherent alpine tectonic unit. The structural and stratigraphic observations in the Piz Terri-Lunschania zone suggest the activity of syn-rift detachments. During the alpine collision these faults are reactivated (and inverted) and played a major role in allowing the Adula subduction, the "Penninic Thrust" above it and in creating the structural complexity of the Central Alps.

Quality of surface water related to land use: a case study in a catchment with small farms and intensive vegetable crop production in southern Brazil

Water degradation is strongly related to agricultural activity. The aim of this study was to evaluate the influence of land use and some environmental components on surface water quality in the Campestre catchment, located in Colombo, state of Parana, Brazil. Physical and chemical attributes were analyzed (total nitrogen, ammonium, nitrate, total phosphorus, electrical conductivity, pH, temperature, turbidity, total solids, biological oxygen demand, chemical oxygen demand and dissolved oxygen). Monthly samples of the river water were taken over one year at eight monitoring sites, distributed over three sub-basins. Overall, water quality was worse in the sub-basin with a higher percentage of agriculture, and was also affected by a lower percentage of native forest and permanent preservation area, and a larger drainage area. Water quality was also negatively affected by the presence of agriculture in the riparian zone. In the summer season, probably due to higher rainfall and intensive soil use, a higher concentration of total nitrogen and particulate nitrogen was observed, as well as higher electrical conductivity, pH and turbidity. All attributes, except for total phosphorus, were in compliance with Brazilian Conama Resolution Nº 357/2005 for freshwater class 1. However, it should be noted that these results referred to the base flow and did not represent a discharge condition since most of the water samples were not collected at or near the rainfall event.

Sentinel lymph node biopsy in nonmelanoma skin cancer patients.

The management of lymph nodes in nonmelanoma skin cancer patients is currently still debated. Merkel cell carcinoma (MCC), squamous cell carcinoma (SCC), pigmented epithelioid melanocytoma (PEM), and other rare skin neoplasms have a well-known risk to spread to regional lymph nodes. The use of sentinel lymph node biopsy (SLNB) could be a promising procedure to assess this risk in clinically N0 patients. Metastatic SNs have been observed in 4.5-28% SCC (according to risk factors), in 9-42% MCC, and in 14-57% PEM. We observed overall 30.8% positive SNs in 13 consecutive patients operated for high-risk nonmelanoma skin cancer between 2002 and 2011 in our institution. These high rates support recommendation to implement SLNB for nonmelanoma skin cancer especially for SCC patients. Completion lymph node dissection following positive SNs is also a matter of discussion especially in PEM. It must be remembered that a definitive survival benefit of SLNB in melanoma patients has not been proven yet. However, because of its low morbidity when compared to empiric elective lymph node dissection or radiation therapy of lymphatic basins, SLNB has allowed sparing a lot of morbidity and could therefore be used in nonmelanoma skin cancer patients, even though a significant impact on survival has not been demonstrated.

Circum-Alpine marine circulation and paleoenvironmental conditions during the Miocene

Trace element and isotopic compositions of marine fossils and sediment were analyzed from several Miocene deposits in the circum-Alpine region in order to reconstruct the paleoceanographic and paleoclimatic changes related to sea level changes, basin evolution and Alpine orogeny. To the north and the east the Alps were border by an epicontinental sea, the Paratethys, while to the south the Mediterranean surrounded the uplifting mountains during the Miocene. The thesis mainly focused on sediments and fossils sampled from Miocene beds of these two oceanic provinces. The north Alpine Molasse, the Vienna and Pannonian Basins were located in the Western and Central Paratethys. O-isotope compositions of well-preserved phosphatic fossils in these sediments support deposition under sub-tropical to warm-temperate climate with water temperatures between 14 to 28 °C for the Miocene. δ18O values of fossil shark teeth from different horizons vary similarly to those of the global trend until the end of the Badenian, however the δ18O values show wider range, which indicates local effects iii the sub-basins. The trend of 87Sr/86Sr in the samples roughly agrees with an open ocean environment for the Miocene. Yet a number of samples deviate from typical open ocean compositions with higher ratios suggesting modification of seawater by local and old terrestrial sources. In contrast, two exceptional teeth from the locality of La Moliere have extremely low δ18O values and low 87Sr/86Sr. However, the REE patterns of their enameloid are similar to those of teeth having O and Sr isotopic compositions typical of a marine setting at this site. Collectively, this suggests that the two teeth formed while the sharks frequented a freshwater environment with very low 18O-content and 87Sr/86Sr controlled by Mesozoic calcareous rocks. This is consistent with a paleogeography of high-elevation (~2300m) Miocene Alps adjacent to a marginal sea. The local effects are also reflected in the εNd values of the Paratethyan fossils, which is compatible with input from ancient crystalline rocks and Mesozoic sediments, while other samples with elevated εNd values indicate an influence of Neogene volcanism on the water budget. Excluding samples whose isotopic compositions reflect a local influence on the water column, an average εNd value of -7.9 ± 0.5 may be inferred for the Paratethys seawater. This value is indistinguishable from the Miocene value of the Indian Ocean, supporting a dominant role of ludo-Pacific water masses in the Paratethys. Regarding the Mediterranean, stable C-and O-isotope compositions of benthic and planktonic foraminifera from the Umbria-Marche region (UMC) have an offset typical for their habitats and the changes in composition mimic global changes, suggesting that the regional conditions of climate and the carbon cycle were controlled by global changes. The radiogenic isotope compositions of the fossil assemblages allow for distinction of periods. From 25 to 19 Ma, high εNd values and low 87Sr/86Sr of sediments and fossils support intense tectonism and volcanism, related to the opening of the western Mediterranean. Between 19 and 13 Ma the Mediterranean has εNd values that are largely controlled by incursion of Indian Ocean water. Brief periods of local hinterland control on seawater compositions are indicated by spikes in the εNd record, coinciding with volcanic events and a short sea-level decrease at about 15.2 Ma. Lower 87Sr/86Sr compared to the open ocean is compatible with rapid uplift of the hinterland and intense influx of Sr from Mesozoic carbonates of the western Apennines, while higher 87Sr/86Sr for other sites indicates erosion of old crustal silicate rocks. Finally, from 13 to 7 Ma the fossils have 87Sr/86Sr similar to those of Miocene seawater and their εNd values indicates fluctuating influence of Atlantic, and Indian Ocean or Paratethys sources of seawater entering the Mediterranean, driven by global sealevel changes and local tectonism. RÉSUMÉ DE LA THÈSE Les compositions en éléments traces et isotopiques de fossiles marins et de sédiments on été analysées à partir de nombreux dépôts marins dans la région circum Alpine dans le but de reconstruire les changements paléocéanographiques et paléoclimatiques liés aux changements du niveau marin, à l'évolution en bassins et à l'orogénie alpine. Au nord et à l'est des Alpes, une mer épicontinentale appelée Paratéthys s'est ouverte, alors que plus au sud la mer Méditerranée bordait au Miocène les Alpes naissantes. Le but de cette recherche est de se concentrer sur les sédiments et les fossiles provenant des couches du Miocènes de ces deux provinces marines. Les bassins de la Molasse Alpine du nord, de Vienne et Pannonien étaient situés au niveau de la Paratéthys Occidentale et Centrale. Les compositions isotopiques de l'oxygène de fossiles phosphatés bien préservés dans ces sédiments étayent la théorie d'un dépôt sous un climat subtropical à tempéré chaud avec des températures entre 14 et 28°C pendant le Miocène. Les valeurs δ18O des fossiles sont similaires à la tendance globale jusqu'à la fin du Badénien. Cependant les larges fluctuations en δ18O indiquent des effets locaux au niveau des sous bassins. En outre, deux dents de requin exceptionnelles présentent des valeurs extrêmement basses de δ18O. Ces données suggèrent que ces deux dents se sont formées alors que les requins fréquentaient un environnement d'eau douce avec de faibles valeurs de 18O. Le calcul de la composition isotopique de l'oxygène de cette eau douce permet d'obtenir une estimation de la paléoélévatian moyenne des Alpes du Miocène (~2300m). La tendance 87Sr/86Sr pour ces échantillons concorde approximativement avec un environnement d'océan ouvert au cours du Miocène. Toutefois un nombre d'échantillons dévie des compositions d'océan ouvert typiques, avec des rapports élevés suggérant des modifications de l'eau de mer par des sources locales et terrestres. Les effets locaux sont aussi reflétés au niveau des valeurs en εNd des fossiles paratéthysiens. Ceci est cohérent avec un apport d'anciennes roches cristallines et de sédiments mésozoïques, tandis que d'autres échantillons avec des valeurs hautes de εNd indiquent une influence d'un volcanisme néogène dans le budget marin. En excluant les échantillons dont les compositions isotopiques confirment une influence locale, une valeur moyenne de εNd de 7.9 t 0.5 peut être déduite pour l'eau de la Parathétys. Cette valeur est semblable à la valeur correspondant à l'Océan Indien durant le Miocène, confirmant un rôle dominant de cet océan dans la Paratéthys. Au niveau de la Méditerranée, les compositions en isotopes stables du Carbone et de l'Oxygène de foraminifères planctoniques et benthique de la région Umbria-Marche présentent un offset typique à leurs habitats. De plus les changements dans leurs compositions suivent les changements globaux, suggérant ainsi que les conditions climatiques régionales et le cycle du carbone étaient contrôlés par des phénomènes globaux. La composition en isotopes radiogéniques d'assemblages fossiles permet une reconnaissance sur trois périodes distinctes. De 25 à 19 millions d'années (Ma), des valeurs élevées de εNd et un faible rapport 87Sr/86Sr dans les sédiments soutiennent l'idée d'une activité tectonique et volcanique intense, liée à l'ouverture de la Méditerranée occidentale. Entre 19 et 13 Ma, la Méditerranée montre des valeurs de εNd qui sont largement contrôlées par une incursion d'eau provenant de l'Océan Indien. En effet, aux alentours de 15,2 Ma, des pics dans l'enregistrement des valeurs de εNd, coïncidant avec des événements volcaniques et de brèves diminutions du niveau marin. Enfin, de 13 à 7 Ma, les fossiles ont des rapports ß7Sr/8fiSr similaires à ceux de l'eau de mer au Miocène. Leurs valeurs de εNd indiquent une influence changeante de l'océan Atlantique, et de l'océan Indien ou des sources d'eau de merde la Parathétys qui entrent dans les bassins méditerranéens. Ce changement est guidé par des modifications globales du niveau marin et par la tectonique locale. RÉSUMÉ DE LA THÈSE (POUR LE GRAND PUBLIC) Les analyses des compositions en éléments traces et isotopiques des fossiles marins sont un outil très utile pour reconstruire les conditions océaniques et climatiques anciennes. Ce travail de thèse se concentre sur les sédiments déposés dans un environnement marin proches des Alpes au cours du Miocène, entre 23 et 7 millions d'années (Ma). Cette période est caractérisée par une tectonique alpine active, ainsi que par des changements climatiques et océanographiques globaux importants. Dans le but de tracer ces changements, les compositions isotopiques du Strontium, du Néodyme, de l'Oxygène et du Carbone ont été analysées dans des fossiles bien préservés ainsi que les sédiments contemporains. Les échantillons proviennent de deux provinces océaniques distinctes, la première est la Mer Méditerranée, et l'autre est une mer épicontinentale appelée Parathétys, qui existait au nord et à l'est des Alpes durant le Miocène. Au niveau de la Parathétys Occidentale et Orientale, les compositions isotopiques d'oxygène de dents de requins confirment un dépôt sous un climat subtropical à tempéré chaud avec des températures d'eau entre 14 et 28°C au Miocène. En outre, deux dents de requins exceptionnelles ont enregistré des compositions isotopiques d'oxygène extrêmement basses. Cela suggère que ces deux dents se sont formées alors que les requins entraient dans un système d'eau douce. Le calcul de la composition isotopique de l'oxygène de cette eau douce permet d'obtenir une estimation de la paléoélévation des Alpes au Miocène qui est aussi élevée que celle d'aujourd'hui. La tendance isotopique du Strontium pour ces échantillons concorde approximativement avec un environnement d'océan ouvert. Cependant un certain nombre d'échantillons indique des modifications de l'eau de mer par des sources terrestres locales. Les effets locaux sont aussi visibles au niveau des compositions isotopiques du Néodyme, qui sont en accord avec un apport provenant de roches cristallines anciennes et de sédiments du Mésozoïque, alors que d'autres échantillons indiquent une influence volcanique néogène dans le budget marin. A l'exclusion des échantillons dont les compositions correspondent à une influence locale, les compositions isotopiques du Néodyme de la Parathétys sont très similaires aux valeurs de l'Océan Indien, montrant ainsi un rôle important des masses d'eau IndoPacifiques dans cette région. Au niveau de la Méditerranée, les compositions en isotopes stables du Carbone et de l'Oxygène de foraminifères planctoniques et benthique de la région Umbria-Marche présentent un offset typique à leurs habitats. De plus, les changements dans leurs compositions suivent les changements globaux, suggérant ainsi que les conditions climatiques régionales et le cycle du carbone étaient contrôlés par des phénomènes globaux. La composition en isotopes radiogéniques d'assemblages fossiles permet une reconnaissance sur trois périodes distinctes. De 25 à 19 Ma, des rapport isotopiques élevés pour le Néodyme et faibles pour le Strontium dans les sédiments et les fossiles soutiennent l'idée d'une activité tectonique et volcanique intense, liée à l'ouverture de la Méditerranée occidentale. Entre 19 et 13 Ma, la Méditerranée présente des rapports isotopiques du Néodyme qui sont largement contrôlés par une incursion d'eau provenant de l'Océan Indien. En effet, aux alentours de 15,2 Ma, des pics dans l'enregistrement des valeurs des isotopes du Néodyme coïncident avec des événements volcaniques et de brèves diminutions du niveau marin. Finalement, de 13 à 7 Ma, les fossiles ont des rapports isotope Strontium similaires à ceux de l'eau de mer au Miocène. Les rapports isotopiques du Néodyme indiquent une influence changeante de l'océan Atlantique, et de l'océan Indien ou des sources d'eau de mer de la Parathétys qui entrent dans les bassins méditerranéens. Ce changement est guidé par des modifications globales du niveau marin et par la tectonique locale.

Permian-Triassic of the Tethys: Carbon isotope sudies

Profiles of carbon isotopes were studied in marine limestones of Late Permian and Early Triassic age of the Tethyan region from 20 sections in Yugoslavia, Greece, Turkey, Armenian SSR, Iran, Pakistan, India, Nepal, and China. The Upper Permian sections continue the high positive values of 13C previously found in Upper Permian basins in NW Europe and western USA. In the more complete sections of Tethys it can now be demonstrated that the values of 13C drop from the Murgabian to the Dzhulfian Stages of the Upper Permian, then sharply to values near zero during the last two biozones of the Dorashamian. These levels of 13C sample the Tethys Sea and the world ocean, and equal values from deep-water sediments at Salamis Greece indicate that they apply to the whole water column. We hypothesize that the high values of 13C are a consequence of Late Paleozoic storage of organic carbon, and that the declines represent an episodic cessation of this organic deposition, and partial oxidation of the organic reservoir, extending over a period of several million years. The carbon isotope profile may reflect parallel complexity in the pattern of mass extinction in Late Permian time. Des profils isotopiques du carbone ont été établis dans des calcaires marins d'âge tardi-permien à  éo-triasique répartis dans 20 endroits du domaine téthysien: Yougoslavie, Grèce, Turquie, République d'Arménie, Iran, Pakistan, Inde, Népal et Chine. Les profils établis dans le Permien supérieur montrent les mêmes valeurs positives de 13C observées antérieurement dans des bassins de même âge en Europe occidentale et dans l'ouest des USA. Dans les profils les plus complets de la Téthys, il est maintenant établi que les valeurs de 13C décroissent depuis le Murgabien jusqu'au Dzhulfien (Permien supérieur) pour devenir proches de zéro dans les deux dernières biozones du Dorasharmen. Ces valeurs de 13C sont caractéristiques de la Téthys et de l'Océan mondial; elles s'appliquent à toutes les profondeurs d'eau, comme en témoignent les valeurs fournies par des sédiments de mer profonde à Salamis (Grèce). Nous formulons l'hypothèse que les hautes valeurs de 13C sont la conséquence du stockage du carbone organique au Paléozoïque supérieur et que leur décroissance traduit un arrêt épisodique de cette sédimentation organique, accompagné d'une oxydation partielle de la matière organique s'étendant sur une période de plusieurs Ma. L'influence parallèle des phénomènes d'extinction massive à le fin du Permien se refléterait également dans les profils isotopiques du carbone.

Unravelling the interaction between tectonic and sedimentary processes during lithospheric thinning in the Alpine Tethys margins

The discovery of exhumed continental mantle and hyper-extended crust in present-day magma-poor rifted margins is at the origin of a paradigm shift within the research field of deep-water rifted margins. It opened new questions about the strain history of rifted margins and the nature and composition of sedimentary, crustal and mantle rocks in rifted margins. Thanks to the benefit of more than one century of work in the Alps and access to world-class outcrops preserving the primary relationships between sediments and crustal and mantle rocks from the fossil Alpine Tethys margins, it is possible to link the subsidence history and syn-rift sedimentary evolution with the strain distribution observed in the crust and mantle rocks exposed in the distal rifted margins. In this paper, we will focus on the transition from early to late rifting that is associated with considerable crustal thinning and a reorganization of the rift system. Crustal thinning is at the origin of a major change in the style of deformation from high-angle to low-angle normal faulting which controls basin-architecture, sedimentary sources and processes and the nature of basement rocks exhumed along the detachment faults in the distal margin. Stratigraphic and isotopic ages indicate that this major change occurred in late Sinemurian time, involving a shift of the syn-rift sedimentation toward the distal domain associated with a major reorganization of the crustal structure with exhumation of lower and middle crust. These changes may be triggered by mantle processes, as indicated by the infiltration of MOR-type magmas in the lithospheric mantle, and the uplift of the Brianconnais domain. Thinning and exhumation of the crust and lithosphere also resulted in the creation of new paleogeographic domains, the Proto Valais and Liguria-Piemonte domains. These basins show a complex, 3D temporal and spatial evolution that might have evolved, at least in the case of the Liguria-Piemonte basin, in the formation of an embryonic oceanic crust. The re-interpretation of the rift evolution and the architecture of the distal rifted margins in the Alps have important implications for the understanding of rifted margins worldwide, but also for the paleogeographic reconstruction of the Alpine domain and its subsequent Alpine compressional overprint.

Hsp70 chaperones accelerate protein translocation and the unfolding of stable protein aggregates by entropic pulling.

Hsp70s are highly conserved ATPase molecular chaperones mediating the correct folding of de novo synthesized proteins, the translocation of proteins across membranes, the disassembly of some native protein oligomers, and the active unfolding and disassembly of stress-induced protein aggregates. Here, we bring thermodynamic arguments and biochemical evidences for a unifying mechanism named entropic pulling, based on entropy loss due to excluded-volume effects, by which Hsp70 molecules can convert the energy of ATP hydrolysis into a force capable of accelerating the local unfolding of various protein substrates and, thus, perform disparate cellular functions. By means of entropic pulling, individual Hsp70 molecules can accelerate unfolding and pulling of translocating polypeptides into mitochondria in the absence of a molecular fulcrum, thus settling former contradictions between the power-stroke and the Brownian ratchet models for Hsp70-mediated protein translocation across membranes. Moreover, in a very different context devoid of membrane and components of the import pore, the same physical principles apply to the forceful unfolding, solubilization, and assisted native refolding of stable protein aggregates by individual Hsp70 molecules, thus providing a mechanism for Hsp70-mediated protein disaggregation.

Influence of bedrock structures on the spatial pattern of erosional landforms in small alpine catchments

Structural settings and lithological characteristics are traditionally assumed to influence the development of erosional landforms, such as gully networks and rock couloirs, in steep mountain rock basins. The structural control of erosion of two small alpine catchments of distinctive rock types is evaluated by comparing the correspondences between the orientations of their gullies and rock couloirs with (1) the sliding orientations of potential slope failures mechanisms, and (2) the orientation of the maximum joint frequency, this latter being considered as the direction exploited primarily by erosion and mass wasting processes. These characteristic orientations can be interpreted as structural weaknesses contributing to the initiation and propagation of erosion. The morphostructural analysis was performed using digital elevation models and field observations. The catchment comprised of magmatic intrusive rocks shows a clear structural control, mostly expressed through potential wedges failure. Such joint configurations have a particular geometry that encourages the development of gullies in hard rock, e.g. through enhanced gravitational and hydrological erosional processes. In the catchment underlain by sedimentary rocks, penetrative joints that act as structural weaknesses seem to be exploited by gullies and rock couloirs. However, the lithological setting and bedding configuration prominently control the development of erosional landforms, and influence not only the local pattern of geomorphic features, but the general morphology of the catchment. The orientations of the maximum joint frequency are clearly associated with the gully network, suggesting that its development is governed by anisotropy in rock strength. These two catchments are typical of bedrock-dominated basins prone to intense processes of debris supply. This study suggests a quantitative approach for describing the relationship between bedrock jointing and geomorphic features geometry. Incorporation of bedrock structure can be relevant when studying processes governing the transfer of clastic material, for the assessment of sediment yields and in landforms evolution models.

A Reply to comments by D. Bar-Yosef M. Stiner on "Prehistoric exploitation of marine resources in Southern Africa with particular reference to shellfish gathering: opportunities and continuities"

I am very grateful to Daniella E. Bar-Yosef Mayer and Mary Stiner for their comments on an article I published in the previous issue of Pyrenae. Having spent many years working with coastal sites in South Africa and now settling in the Mediterranean academic landscape, I value the feedback from these two well-known archaeologists who have dedicated years of hard work in this later part of the world. Their opinions are very much appreciated for they allow me to bring new contexts to some of the (old) questions I have pursued in South Africa, an exercise that would help me with the process of broadening my research interests to the Mediterranean region.

Pieces of Iowa’s Past, March 21, 2012

Pieces of Iowa’s Past, published by the Iowa State Capitol Tour Guides weekly during the legislative session, features historical facts about Iowa, the Capitol, and the early workings of state government. All historical publications are reproduced here with the actual spelling, punctuation, and grammar retained. March 21, 2012 THIS WEEK: Quick Work at Carlisle(From the Indianola Tribune, December 20, 1877) BACKGROUND: Lewis Todhunter was born in Fayette County, Ohio, April 6, 1817. He was admitted to the bar in Highland County, Ohio, in 1848. Todhunter came to Iowa in 1850, settling along the Des Moines River in Polk County, where he was engaged in farming and selling goods. In 1854, he moved to Indianola and began the practice of law, continuing in that profession for more than a quarter of a century. He served as prosecuting attorney, county auditor, treasurer, and mayor of the city. He was a member of the third constitutional convention, which met at Iowa City in 1857, representing Warren, Madison, Adair, and Cass counties in that body and had the honor of assisting in making the first laws of the state. Todhunter served in the army during the Civil War from 1863-1865 as assistant quartermaster with rank of Captain. He is perhaps widest known, however, as a temperance leader and earnest worker. He joined in the Washingtonian movement in 1840 and was active in temperance reformation for the rest of his life.