Rock Magnetic Studies of the Neuschwanstein EL6 Chondrite : Implications on the Origin of its Natural Remanent Magnetization

Peer reviewe

Improved Surgical Technique for Laparoscopic Roux-en-Y Gastric Bypass Reduces Complications at the Gastrojejunostomy

Roux-en-Y gastric bypass (RYGBP) is one of the most commonly performed bariatric procedures for morbidly obese patients. It is associated with effective long-term weight loss, but can lead to significant complications, especially at the gastrojejunostomy (GJS). All the patients undergoing laparoscopic RYGBP at one of our two institutions were included in this study. The prospectively collected data were reviewed retrospectively for the purpose of this study, in which we compared two different techniques for the construction of the GJS and their effects on the incidence of complications. In group A, anastomosis was performed on the posterior aspect of the gastric pouch. In group B, it was performed across the staple line used to form the gastric pouch. A 21-mm circular stapler was used in all patients. A total of 1,128 patients were included between June 1999 and September 2009—639 in group A and 488 in group B. Sixty patients developed a total of 65 complications at the GJS, with 14 (1.2%) leaks, 42 (3.7%) strictures, and 9 (0.8%) marginal ulcers. Leaks (0.2% versus 2%, p = 0.005) and strictures (0.8% versus 5.9%, p < 0.0001) were significantly fewer in group B than in group A. Improved surgical technique, as we propose, with the GJS across the staple line used to form the gastric pouch, significantly reduces the rate of anastomotic complications at the GJS. A circular 21-mm stapler can be used with a low complication rate, and especially a low stricture rate. Additional methods to limit complications at the GJS are probably not routinely warrante

Directional changes of the geomagnetic field in West Africa: Insights from the metallurgical site of Korsimoro

This work shows the first archeomagnetic directions from Western Africa measured on 32 iron smelting kilns dated between 650 and 1800 AD. The archeological excavation of the vast metallurgical site of Korsimoro established the existence of four distinct iron-smelting techniques. The time-frame of each technique could be clearly determined with radiocarbon dating. Many of the kilns investigated in this study could also be dated individually with residual charcoals found in their inside. The results indicate that the inclination of the field changed gradually from shallow normal to shallow reversed during 800 to 1300 AD, and then went back to shallow normal around 1600–1700 AD. The declination was instead stable around 10°E between 800 and 1400 AD, thereafter it started changing towards North. This trend correlates well with available secular variation curves from the Balkan and from Spain, and indicates that the field variation in West Africa was similar to the one in Europe

Reconstructing the geomagnetic field in west africa: first absolute intensity results from Burkina Faso

We present absolute geomagnetic intensities from iron smelting furnaces discovered at the metallurgical site of Korsimoro, Burkina Faso. Up to now, archaeologists recognized four different types of furnaces based on different construction methods, which were related to four subsequent time periods. Additionally, radiocarbon ages obtained from charcoal confine the studied furnaces to ages ranging from 700–1700 AD, in good agreement with the archaeologically determined time periods for each type of furnace. Archaeointensity results reveal three main groups of Arai diagrams. The first two groups contain specimens with either linear Arai diagrams, or slightly curved diagrams or two phases of magnetization. The third group encompasses specimens with strong zigzag or curvature in their Arai diagrams. Specimens of the first two groups were accepted after applying selection criteria to guarantee the high quality of the results. Our data compared to palaeosecular variation curves show a similar decreasing trend between 900–1500 AD. However, they reveal larger amplitudes at around 800 AD and 1650 AD than the reference curves and geomagnetic field models. Furthermore, they agree well with archaeomagnetic data from Mali and Senegal around 800 AD and with volcanic data around 1700 AD

New directional archeomagnetic data of burned cave sediments from Switzerland and geomagnetic field variations in Central Europe

This paper presents new directional archeomagnetic data from nine Meso-/Neolithic fireplaces, sampled in a cave shelter, at Arconciel, in western Switzerland. Rock magnetic measurements indicate a homogenous magnetic mineralogy in all fireplaces, with magnetite as the main magnetic carrier. The remanent magnetization is stable and generally shows one characteristic directional component. Nine new directions, which were obtained from Arconciel, are combined with 356 other archeomagnetic data from a circular area with a radius of 700km around this site, to obtain a penalized least square spline fit for the past 9000yr. We found in general good agreement with other local compilations, such as the Balkan curve, the regional SCHA.DIF.8k model and with lake sediments from UK, Fennoscandia and Switzerland. Nevertheless, a time lag of several centuries is observed for a declination maximum between the archeomagnetic spline fit and the other European data records around 5900BC. This time lag is also observed in the Swiss lake sediment record; therefore we interpret this shift as a local feature of the Earth's magnetic fiel

GEOMAGIA50.v3: 1. general structure and modifications to the archeological and volcanic database

Background: GEOMAGIA50.v3 is a comprehensive online database providing access to published paleomagnetic, rock magnetic, and chronological data from a variety of materials that record Earth’s magnetic field over the past 50 ka.Findings: Since its original release in 2006, the structure and function of the database have been updated and a significant number of data have been added. Notable modifications are the following: (1) the inclusion of additional intensity, directional and metadata from archeological and volcanic materials and an improved documentation of radiocarbon dates; (2) a new data model to accommodate paleomagnetic, rock magnetic, and chronological data from lake and marine sediments; (3) a refinement of the geographic constraints in the archeomagnetic/volcanic query allowing selection of particular locations; (4) more flexible methodological and statistical constraints in the archeomagnetic/volcanic query; (5) the calculation of predictions of the Holocene geomagnetic field from a series of time varying global field models; (6) searchable reference lists; and (7) an updated web interface. This paper describes general modifications to the database and specific aspects of the archeomagnetic and volcanic database. The reader is referred to a companion publication for a description of the sediment database.Conclusions: The archeomagnetic and volcanic part of GEOMAGIA50.v3 currently contains 14,645 data (declination, inclination, and paleointensity) from 461 studies published between 1959 and 2014. We review the paleomagnetic methods used to obtain these data and discuss applications of the data within the database. The database continues to expand as legacy data are added and new studies published. The web-based interface can be found at http://geomagia.gfz-potsdam.de webcite

GEOMAGIA50.v3: 2. A new paleomagnetic database for lake and marine sediments

Background: GEOMAGIA50.v3 for sediments is a comprehensive online database providing access to published paleomagnetic, rock magnetic, and chronological data obtained from lake and marine sediments deposited over the past 50 ka. Its objective is to catalogue data that will improve our understanding of changes in the geomagnetic field, physical environments, and climate.Findings: GEOMAGIA50.v3 for sediments builds upon the structure of the pre-existing GEOMAGIA50 database for magnetic data from archeological and volcanic materials. A strong emphasis has been placed on the storage of geochronological data, and it is the first magnetic archive that includes comprehensive radiocarbon age data from sediments. The database will be updated as new sediment data become available.Conclusions: The web-based interface for the sediment database is located at http://geomagia.gfz-potsdam.de/geomagiav3/SDquery.php webcite. This paper is a companion to Brown et al. (Earth Planets Space doi:10.1186/s40623-015-0232-0, 2015) and describes the data types, structure, and functionality of the sediment database

Evolution of the solar irradiance during the Holocene

Aims. We present a physically consistent reconstruction of the total solar irradiance for the Holocene. Methods. We extend the SATIRE models to estimate the evolution of the total (and partly spectral) solar irradiance over the Holocene. The basic assumption is that the variations of the solar irradiance are due to the evolution of the dark and bright magnetic features on the solar surface. The evolution of the decadally averaged magnetic flux is computed from decadal values of cosmogenic isotope concentrations recorded in natural archives employing a series of physics-based models connecting the processes from the modulation of the cosmic ray flux in the heliosphere to their record in natural archives. We then compute the total solar irradiance (TSI) as a linear combination of the jth and jth + 1 decadal values of the open magnetic flux. Results. Reconstructions of the TSI over the Holocene, each valid for a di_erent paleomagnetic time series, are presented. Our analysis suggests that major sources of uncertainty in the TSI in this model are the heritage of the uncertainty of the TSI since 1610 reconstructed from sunspot data and the uncertainty of the evolution of the Earth's magnetic dipole moment. The analysis of the distribution functions of the reconstructed irradiance for the last 3000 years indicates that the estimates based on the virtual axial dipole moment are significantly lower at earlier times than the reconstructions based on the virtual dipole moment. Conclusions. We present the first physics-based reconstruction of the total solar irradiance over the Holocene, which will be of interest for studies of climate change over the last 11500 years. The reconstruction indicates that the decadally averaged total solar irradiance ranges over approximately 1.5 W/m2 from grand maxima to grand minima

Conformal prediction and copula based methods for profile monitioring

LAUREA MAGISTRALEIn molti processi industriali la complessità è aumentata nel corso degli anni e, parallelamente, la necessità di monitorare i processi, al fine di trovare comportamenti anomali, è diventata sempre più essenziale. Per questo motivo, il monitoraggio dei profili, un recente campo di ricerca nel controllo dei processi statistici, sta attirando l’interesse di molti ricercatori. Con questa tesi, il nostro obiettivo è proporre uno strumento aggiuntivo, la cosiddetta p-value function, che andrà ad integrare l’approccio tradizionale utilizzato nel monitoraggio dei profili. In particolare, la nostra metodologia, basata sulla Conformal prediction e sulla teoria delle copule, è in grado di riconoscere non solo se è presente un’anomalia, ma anche quale parte del dominio è responsabile di quel particolare comportamento. Per verificare I punti di forza e/o debolezza del nostro metodo, la discussione è accompagnata da applicazioni a dataset presenti in letteratura e da uno studio su dati simulati. Un caso reale, vale a dire i Profili di Densità Verticale (VDP), è presentato per illustrare il potenziale della nostra procedura in applicazioni reali.In many industrial processes the intrinsic complexity has increased over years and, in parallel, the necessity to monitor the processes, in order to detect anomalous patterns has become more and more essential. For this reason, profile monitoring, a recent field of research in Statistical Process Control, is attracting the interest of many researchers. In this work, our aim is to propose an additional tool, a novel conformal based p-value function, that integrates the traditional approach used in profile monitoring. Our methodology, based on Conformal prediction and Copula estimation, is able to recognize not only if an anomaly is present, but also which part of the domain is responsible for that strange behaviour. To check the goodness of our method, we go through applications to literature datasets and simulations study. A real case study, namely the analysis on Vertical Density Profiles (VDP), is presented in order to illustrate the potential of our procedure in real applications

Milvexian and other drugs targeting Factor XI: a new era of anticoagulation?

For almost 90 years, the discovery and development of anticoagulant drugs have focused on maximizing their antithrombotic efficacy while minimizing the risk of bleeding, in addition to providing manageable compounds with predictable and/or monitorable effects [...]