Evaluation of movements of lower limbs in non-professional ballet dancers: hip abduction and flexion

Background The literature indicated that the majority of professional ballet dancers present static and active dynamic range of motion difference between left and right lower limbs, however, no previous study focused this difference in non-professional ballet dancers. In this study we aimed to evaluate active movements of the hip in non-professional classical dancers. Methods We evaluated 10 non professional ballet dancers (16-23 years old). We measured the active range of motion and flexibility through Well Banks. We compared active range of motion between left and right sides (hip flexion and abduction) and performed correlation between active movements and flexibility. Results There was a small difference between the right and left sides of the hip in relation to the movements of flexion and abduction, which suggest the dominant side of the subjects, however, there was no statistical significance. Bank of Wells test revealed statistical difference only between the 1st and the 3rd measurement. There was no correlation between the movements of the hip (abduction and flexion, right and left sides) with the three test measurements of the bank of Wells. Conclusion There is no imbalance between the sides of the hip with respect to active abduction and flexion movements in non-professional ballet dancers.

Cranberries and lower urinary tract infection prevention

Lower urinary tract infections are very common diseases. Recurrent urinary tract infections remain challenging to treat because the main treatment option is long-term antibiotic prophylaxis; however, this poses a risk for the emergence of bacterial resistance. Some options to avoid this risk are available, including the use of cranberry products. This article reviews the key methods in using cranberries as a preventive measure for lower urinary tract infections, including in vitro studies and clinical trials.

Incidence of lower limb bone fractures in female individuals of Aracaju (Sergipe), Brazil

Studies indicate that the number of hip bone fractures caused by osteoporosis may rise from 1.66 to 6.26 million until 2050, worldwide. For this reason, implementation of preventive measures becomes a necessity. Female individuals are usually more affected due to a variety of factors including old age, early menopause, chronicle disease in the family history, calcium deficit, as well as the lack of physical exercise (sedentary individual). The aim of this study was to estimate the incidence of hip and lower limb fracture in female individuals’ resident in Aracaju city. From the period of January 2008-2009, around of 300 fracture cases were of lower limb analyzed from females. The incidence of femur fractures in women increased according to age group, 66.17 individuals per 10,000 inhabitants (over 60 years-old). These findings allow us to conclude that the incidence of hip and lower limb bone fractures among women over 60 years were more significant in the femur.

Eruptive history of the Krakatau volcanic complex, Indonesia

[EN] The 1883 eruption of Krakatau is one of the best known volcanic events in the world, although it was not the largest, nor the deadliest of known eruptions. However, the eruption happened in a critical moment (just after the first global telegraph network was established) and in a strategic place (the Sunda Straits were a naval traffic hot spot at that time). The lecture will explore these events in some detail before presenting an outline on ongoing multidisciplinary efforts to unravel the past and present day plumbing systems of the 1883 eruption and that of the active Anak Krakatau cone. A mid- and a lower-crustal magma storage level exist beneath the volcano, placing significant emphasis on magma-crust interaction in the uppermost, sediment-rich crust. This final aspect shares similarities with the 2011/2012 El Hierro eruption, highlighting the relevance of the interaction between ascending magmas and marine deposits that oceanic magmas have to pass. At Krakatau, shallow-level crustal contamination offers a possible explanation for the explosive nature of the 1883 eruption and also for those of the presently active Anak Krakatau edifice and helps constrain location, style and processes of subvolcanic magma storage.

Retrieval of trace gases vertical profile in the lower atmosphere combining. Differential Optical Absorption Spectroscopy with radiative transfer models

The motivation for the work presented in this thesis is to retrieve profile information for the atmospheric trace constituents nitrogen dioxide (NO2) and ozone (O3) in the lower troposphere from remote sensing measurements. The remote sensing technique used, referred to as Multiple AXis Differential Optical Absorption Spectroscopy (MAX-DOAS), is a recent technique that represents a significant advance on the well-established DOAS, especially for what it concerns the study of tropospheric trace consituents. NO2 is an important trace gas in the lower troposphere due to the fact that it is involved in the production of tropospheric ozone; ozone and nitrogen dioxide are key factors in determining the quality of air with consequences, for example, on human health and the growth of vegetation. To understand the NO2 and ozone chemistry in more detail not only the concentrations at ground but also the acquisition of the vertical distribution is necessary. In fact, the budget of nitrogen oxides and ozone in the atmosphere is determined both by local emissions and non-local chemical and dynamical processes (i.e. diffusion and transport at various scales) that greatly impact on their vertical and temporal distribution: thus a tool to resolve the vertical profile information is really important. Useful measurement techniques for atmospheric trace species should fulfill at least two main requirements. First, they must be sufficiently sensitive to detect the species under consideration at their ambient concentration levels. Second, they must be specific, which means that the results of the measurement of a particular species must be neither positively nor negatively influenced by any other trace species simultaneously present in the probed volume of air. Air monitoring by spectroscopic techniques has proven to be a very useful tool to fulfill these desirable requirements as well as a number of other important properties. During the last decades, many such instruments have been developed which are based on the absorption properties of the constituents in various regions of the electromagnetic spectrum, ranging from the far infrared to the ultraviolet. Among them, Differential Optical Absorption Spectroscopy (DOAS) has played an important role. DOAS is an established remote sensing technique for atmospheric trace gases probing, which identifies and quantifies the trace gases in the atmosphere taking advantage of their molecular absorption structures in the near UV and visible wavelengths of the electromagnetic spectrum (from 0.25 μm to 0.75 μm). Passive DOAS, in particular, can detect the presence of a trace gas in terms of its integrated concentration over the atmospheric path from the sun to the receiver (the so called slant column density). The receiver can be located at ground, as well as on board an aircraft or a satellite platform. Passive DOAS has, therefore, a flexible measurement configuration that allows multiple applications. The ability to properly interpret passive DOAS measurements of atmospheric constituents depends crucially on how well the optical path of light collected by the system is understood. This is because the final product of DOAS is the concentration of a particular species integrated along the path that radiation covers in the atmosphere. This path is not known a priori and can only be evaluated by Radiative Transfer Models (RTMs). These models are used to calculate the so called vertical column density of a given trace gas, which is obtained by dividing the measured slant column density to the so called air mass factor, which is used to quantify the enhancement of the light path length within the absorber layers. In the case of the standard DOAS set-up, in which radiation is collected along the vertical direction (zenith-sky DOAS), calculations of the air mass factor have been made using “simple” single scattering radiative transfer models. This configuration has its highest sensitivity in the stratosphere, in particular during twilight. This is the result of the large enhancement in stratospheric light path at dawn and dusk combined with a relatively short tropospheric path. In order to increase the sensitivity of the instrument towards tropospheric signals, measurements with the telescope pointing the horizon (offaxis DOAS) have to be performed. In this circumstances, the light path in the lower layers can become very long and necessitate the use of radiative transfer models including multiple scattering, the full treatment of atmospheric sphericity and refraction. In this thesis, a recent development in the well-established DOAS technique is described, referred to as Multiple AXis Differential Optical Absorption Spectroscopy (MAX-DOAS). The MAX-DOAS consists in the simultaneous use of several off-axis directions near the horizon: using this configuration, not only the sensitivity to tropospheric trace gases is greatly improved, but vertical profile information can also be retrieved by combining the simultaneous off-axis measurements with sophisticated RTM calculations and inversion techniques. In particular there is a need for a RTM which is capable of dealing with all the processes intervening along the light path, supporting all DOAS geometries used, and treating multiple scattering events with varying phase functions involved. To achieve these multiple goals a statistical approach based on the Monte Carlo technique should be used. A Monte Carlo RTM generates an ensemble of random photon paths between the light source and the detector, and uses these paths to reconstruct a remote sensing measurement. Within the present study, the Monte Carlo radiative transfer model PROMSAR (PROcessing of Multi-Scattered Atmospheric Radiation) has been developed and used to correctly interpret the slant column densities obtained from MAX-DOAS measurements. In order to derive the vertical concentration profile of a trace gas from its slant column measurement, the AMF is only one part in the quantitative retrieval process. One indispensable requirement is a robust approach to invert the measurements and obtain the unknown concentrations, the air mass factors being known. For this purpose, in the present thesis, we have used the Chahine relaxation method. Ground-based Multiple AXis DOAS, combined with appropriate radiative transfer models and inversion techniques, is a promising tool for atmospheric studies in the lower troposphere and boundary layer, including the retrieval of profile information with a good degree of vertical resolution. This thesis has presented an application of this powerful comprehensive tool for the study of a preserved natural Mediterranean area (the Castel Porziano Estate, located 20 km South-West of Rome) where pollution is transported from remote sources. Application of this tool in densely populated or industrial areas is beginning to look particularly fruitful and represents an important subject for future studies.

New functional and biomechanical assessments for the improvement of the surgical navigation systems for joint replacement in the human lower limb

In case of severe osteoarthritis at the knee causing pain, deformity, and loss of stability and mobility, the clinicians consider that the substitution of these surfaces by means of joint prostheses. The objectives to be pursued by this surgery are: complete pain elimination, restoration of the normal physiological mobility and joint stability, correction of all deformities and, thus, of limping. The knee surgical navigation systems have bee developed in computer-aided surgery in order to improve the surgical final outcome in total knee arthroplasty. These systems provide the surgeon with quantitative and real-time information about each surgical action, like bone cut executions and prosthesis component alignment, by mean of tracking tools rigidly fixed onto the femur and the tibia. Nevertheless, there is still a margin of error due to the incorrect surgical procedures and to the still limited number of kinematic information provided by the current systems. Particularly, patello-femoral joint kinematics is not considered in knee surgical navigation. It is also unclear and, thus, a source of misunderstanding, what the most appropriate methodology is to study the patellar motion. In addition, also the knee ligamentous apparatus is superficially considered in navigated total knee arthroplasty, without taking into account how their physiological behavior is altered by this surgery. The aim of the present research work was to provide new functional and biomechanical assessments for the improvement of the surgical navigation systems for joint replacement in the human lower limb. This was mainly realized by means of the identification and development of new techniques that allow a thorough comprehension of the functioning of the knee joint, with particular attention to the patello-femoral joint and to the main knee soft tissues. A knee surgical navigation system with active markers was used in all research activities presented in this research work. Particularly, preliminary test were performed in order to assess the system accuracy and the robustness of a number of navigation procedures. Four studies were performed in-vivo on patients requiring total knee arthroplasty and randomly implanted by means of traditional and navigated procedures in order to check for the real efficacy of the latter with respect to the former. In order to cope with assessment of patello-femoral joint kinematics in the intact and replaced knees, twenty in-vitro tests were performed by using a prototypal tracking tool also for the patella. In addition to standard anatomical and articular recommendations, original proposals for defining the patellar anatomical-based reference frame and for studying the patello-femoral joint kinematics were reported and used in these tests. These definitions were applied to two further in-vitro tests in which, for the first time, also the implant of patellar component insert was fully navigated. In addition, an original technique to analyze the main knee soft tissues by means of anatomical-based fiber mappings was also reported and used in the same tests. The preliminary instrumental tests revealed a system accuracy within the millimeter and a good inter- and intra-observer repeatability in defining all anatomical reference frames. In in-vivo studies, the general alignments of femoral and tibial prosthesis components and of the lower limb mechanical axis, as measured on radiographs, was more satisfactory, i.e. within ±3°, in those patient in which total knee arthroplasty was performed by navigated procedures. As for in-vitro tests, consistent patello-femoral joint kinematic patterns were observed over specimens throughout the knee flexion arc. Generally, the physiological intact knee patellar motion was not restored after the implant. This restoration was successfully achieved in the two further tests where all component implants, included the patellar insert, were fully navigated, i.e. by means of intra-operative assessment of also patellar component positioning and general tibio-femoral and patello-femoral joint assessment. The tests for assessing the behavior of the main knee ligaments revealed the complexity of the latter and the different functional roles played by the several sub-bundles compounding each ligament. Also in this case, total knee arthroplasty altered the physiological behavior of these knee soft tissues. These results reveal in-vitro the relevance and the feasibility of the applications of new techniques for accurate knee soft tissues monitoring, patellar tracking assessment and navigated patellar resurfacing intra-operatively in the contest of the most modern operative techniques. This present research work gives a contribution to the much controversial knowledge on the normal and replaced of knee kinematics by testing the reported new methodologies. The consistence of these results provides fundamental information for the comprehension and improvements of knee orthopedic treatments. In the future, the reported new techniques can be safely applied in-vivo and also adopted in other joint replacements.

Meccanismi di formazione dei tubi di lava

Two analytical models are proposed to describe two different mechanisms of lava tubes formation. A first model is introduced to describe the development of a solid crust in the central region of the channel, and the formation of a tube when crust widens until it reaches the leve\'es. The Newtonian assumption is considered and the steady state Navier- Stokes equation in a rectangular conduit is solved. A constant heat flux density assigned at the upper flow surface resumes the combined effects of two thermal processes: radiation and convection into the atmosphere. Advective terms are also included, by the introduction of velocity into the expression of temperature. Velocity is calculated as an average value over the channel width, so that lateral variations of temperature are neglected. As long as the upper flow surface cools, a solid layer develops, described as a plastic body, having a resistance to shear deformation. If the applied shear stress exceeds this resistance, crust breaks, otherwise, solid fragments present at the flow surface can weld together forming a continuous roof, as it happens in the sidewall flow regions. Variations of channel width, ground slope and effusion rate are analyzed, as parameters that strongly affect the shear stress values. Crust growing is favored when the channel widens, and tube formation is possible when the ground slope or the effusion rate reduce. A comparison of results is successfully made with data obtained from the analysis of pictures of actual flows. The second model describes the formation of a stable, well defined crust along both channel sides, their growing towards the center and their welding to form the tube roof. The fluid motion is described as in the model above. Thermal budget takes into account conduction into the atmosphere, and advection is included considering the velocity depending both on depth and channel width. The solidified crust has a non uniform thickness along the channel width. Stresses acting on the crust are calculated using the equations of the elastic thin plate, pinned at its ends. The model allows to calculate the distance where crust thickness is able to resist the drag of the underlying fluid and to sustain its weight by itself, and the level of the fluid can lower below the tube roof. Viscosity and thermal conductivity have been experimentally investigated through the use of a rotational viscosimeter. Analyzing samples coming from Mount Etna (2002) the following results have been obtained: the fluid is Newtonian and the thermal conductivity is constant in a range of temperature above the liquidus. For lower temperature, the fluid becomes non homogeneous, and the used experimental techniques are not able to detect any properties, because measurements are not reproducible.

Crustal heterogeneities and complexities of fault processes

In this work we study the relation between crustal heterogeneities and complexities in fault processes. The first kind of heterogeneity considered involves the concept of asperity. The presence of an asperity in the hypocentral region of the M = 6.5 earthquake of June 17-th, 2000 in the South Iceland Seismic Zone was invoked to explain the change of seismicity pattern before and after the mainshock: in particular, the spatial distribution of foreshock epicentres trends NW while the strike of the main fault is N 7◦ E and aftershocks trend accordingly; the foreshock depths were typically deeper than average aftershock depths. A model is devised which simulates the presence of an asperity in terms of a spherical inclusion, within a softer elastic medium in a transform domain with a deviatoric stress field imposed at remote distances (compressive NE − SW, tensile NW − SE). An isotropic compressive stress component is induced outside the asperity, in the direction of the compressive stress axis, and a tensile component in the direction of the tensile axis; as a consequence, fluid flow is inhibited in the compressive quadrants while it is favoured in tensile quadrants. Within the asperity the isotropic stress vanishes but the deviatoric stress increases substantially, without any significant change in the principal stress directions. Hydrofracture processes in the tensile quadrants and viscoelastic relaxation at depth may contribute to lower the effective rigidity of the medium surrounding the asperity. According to the present model, foreshocks may be interpreted as induced, close to the brittle-ductile transition, by high pressure fluids migrating upwards within the tensile quadrants; this process increases the deviatoric stress within the asperity which eventually fails, becoming the hypocenter of the mainshock, on the optimally oriented fault plane. In the second part of our work we study the complexities induced in fault processes by the layered structure of the crust. In the first model proposed we study the case in which fault bending takes place in a shallow layer. The problem can be addressed in terms of a deep vertical planar crack, interacting with a shallower inclined planar crack. An asymptotic study of the singular behaviour of the dislocation density at the interface reveals that the density distribution has an algebraic singularity at the interface of degree ω between -1 and 0, depending on the dip angle of the upper crack section and on the rigidity contrast between the two media. From the welded boundary condition at the interface between medium 1 and 2, a stress drop discontinuity condition is obtained which can be fulfilled if the stress drop in the upper medium is lower than required for a planar trough-going surface: as a corollary, a vertically dipping strike-slip fault at depth may cross the interface with a sedimentary layer, provided that the shallower section is suitably inclined (fault "refraction"); this results has important implications for our understanding of the complexity of the fault system in the SISZ; in particular, we may understand the observed offset of secondary surface fractures with respect to the strike direction of the seismic fault. The results of this model also suggest that further fractures can develop in the opposite quadrant and so a second model describing fault branching in the upper layer is proposed. As the previous model, this model can be applied only when the stress drop in the shallow layer is lower than the value prescribed for a vertical planar crack surface. Alternative solutions must be considered if the stress drop in the upper layer is higher than in the other layer, which may be the case when anelastic processes relax deviatoric stress in layer 2. In such a case one through-going crack cannot fulfil the welded boundary conditions and unwelding of the interface may take place. We have solved this problem within the theory of fracture mechanics, employing the boundary element method. The fault terminates against the interface in a T-shaped configuration, whose segments interact among each other: the lateral extent of the unwelded surface can be computed in terms of the main fault parameters and the stress field resulting in the shallower layer can be modelled. A wide stripe of high and nearly uniform shear stress develops above the unwelded surface, whose width is controlled by the lateral extension of unwelding. Secondary shear fractures may then open within this stripe, according to the Coulomb failure criterion, and the depth of open fractures opening in mixed mode may be computed and compared with the well studied fault complexities observed in the field. In absence of the T-shaped decollement structure, stress concentration above the seismic fault would be difficult to reconcile with observations, being much higher and narrower.

Constraints on mantle melting from major and trace element systematics in residual abyssal peridotites

ZusammenfassungDie Bildung von mittelozeanischen Rückenbasalten (MORB) ist einer der wichtigsten Stoffflüsse der Erde. Jährlich wird entlang der 75.000 km langen mittelozeanischen Rücken mehr als 20 km3 neue magmatische Kruste gebildet, das sind etwa 90 Prozent der globalen Magmenproduktion. Obwohl ozeanische Rücken und MORB zu den am meisten untersuchten geologischen Themenbereichen gehören, existieren weiterhin einige Streit-fragen. Zu den wichtigsten zählt die Rolle von geodynamischen Rahmenbedingungen, wie etwa Divergenzrate oder die Nähe zu Hotspots oder Transformstörungen, sowie der absolute Aufschmelzgrad, oder die Tiefe, in der die Aufschmelzung unter den Rücken beginnt. Diese Dissertation widmet sich diesen Themen auf der Basis von Haupt- und Spurenelementzusammensetzungen in Mineralen ozeanischer Mantelgesteine.Geochemische Charakteristika von MORB deuten darauf hin, dass der ozeanische Mantel im Stabilitätsfeld von Granatperidotit zu schmelzen beginnt. Neuere Experimente zeigen jedoch, dass die schweren Seltenerdelemente (SEE) kompatibel im Klinopyroxen (Cpx) sind. Aufgrund dieser granatähnlichen Eigenschaft von Cpx wird Granat nicht mehr zur Erklärung der MORB Daten benötigt, wodurch sich der Beginn der Aufschmelzung zu geringeren Drucken verschiebt. Aus diesem Grund ist es wichtig zu überprüfen, ob diese Hypothese mit Daten von abyssalen Peridotiten in Einklang zu bringen ist. Diese am Ozeanboden aufgeschlossenen Mantelfragmente stellen die Residuen des Aufschmelz-prozesses dar, und ihr Mineralchemismus enthält Information über die Bildungs-bedingungen der Magmen. Haupt- und Spurenelementzusammensetzungen von Peridotit-proben des Zentralindischen Rückens (CIR) wurden mit Mikrosonde und Ionensonde bestimmt, und mit veröffentlichten Daten verglichen. Cpx der CIR Peridotite weisen niedrige Verhältnisse von mittleren zu schweren SEE und hohe absolute Konzentrationen der schweren SEE auf. Aufschmelzmodelle eines Spinellperidotits unter Anwendung von üblichen, inkompatiblen Verteilungskoeffizienten (Kd's) können die gemessenen Fraktionierungen von mittleren zu schweren SEE nicht reproduzieren. Die Anwendung der neuen Kd's, die kompatibles Verhalten der schweren SEE im Cpx vorhersagen, ergibt zwar bessere Resultate, kann jedoch nicht die am stärksten fraktionierten Proben erklären. Darüber hinaus werden sehr hohe Aufschmelzgrade benötigt, was nicht mit Hauptelementdaten in Einklang zu bringen ist. Niedrige (~3-5%) Aufschmelzgrade im Stabilitätsfeld von Granatperidotit, gefolgt von weiterer Aufschmelzung von Spinellperidotit kann jedoch die Beobachtungen weitgehend erklären. Aus diesem Grund muss Granat weiterhin als wichtige Phase bei der Genese von MORB betrachtet werden (Kapitel 1).Eine weitere Hürde zum quantitativen Verständnis von Aufschmelzprozessen unter mittelozeanischen Rücken ist die fehlende Korrelation zwischen Haupt- und Spuren-elementen in residuellen abyssalen Peridotiten. Das Cr/(Cr+Al) Verhältnis (Cr#) in Spinell wird im Allgemeinen als guter qualitativer Indikator für den Aufschmelzgrad betrachtet. Die Mineralchemie der CIR Peridotite und publizierte Daten von anderen abyssalen Peridotiten zeigen, dass die schweren SEE sehr gut (r2 ~ 0.9) mit Cr# der koexistierenden Spinelle korreliert. Die Auswertung dieser Korrelation ergibt einen quantitativen Aufschmelz-indikator für Residuen, welcher auf dem Spinellchemismus basiert. Damit kann der Schmelzgrad als Funktion von Cr# in Spinell ausgedrückt werden: F = 0.10×ln(Cr#) + 0.24 (Hellebrand et al., Nature, in review; Kapitel 2). Die Anwendung dieses Indikators auf Mantelproben, für die keine Ionensondendaten verfügbar sind, ermöglicht es, geochemische und geophysikalischen Daten zu verbinden. Aus geodynamischer Perspektive ist der Gakkel Rücken im Arktischen Ozean von großer Bedeutung für das Verständnis von Aufschmelzprozessen, da er weltweit die niedrigste Divergenzrate aufweist und große Transformstörungen fehlen. Publizierte Basaltdaten deuten auf einen extrem niedrigen Aufschmelzgrad hin, was mit globalen Korrelationen im Einklang steht. Stark alterierte Mantelperidotite einer Lokalität entlang des kaum beprobten Gakkel Rückens wurden deshalb auf Primärminerale untersucht. Nur in einer Probe sind oxidierte Spinellpseudomorphosen mit Spuren primärer Spinelle erhalten geblieben. Ihre Cr# ist signifikant höher als die einiger Peridotite von schneller divergierenden Rücken und ihr Schmelzgrad ist damit höher als aufgrund der Basaltzusammensetzungen vermutet. Der unter Anwendung des oben erwähnten Indikators ermittelte Schmelzgrad ermöglicht die Berechnung der Krustenmächtigkeit am Gakkel Rücken. Diese ist wesentlich größer als die aus Schweredaten ermittelte Mächtigkeit, oder die aus der globalen Korrelation zwischen Divergenzrate und mittels Seismik erhaltene Krustendicke. Dieses unerwartete Ergebnis kann möglicherweise auf kompositionelle Heterogenitäten bei niedrigen Schmelzgraden, oder auf eine insgesamt größere Verarmung des Mantels unter dem Gakkel Rücken zurückgeführt werden (Hellebrand et al., Chem.Geol., in review; Kapitel 3).Zusätzliche Informationen zur Modellierung und Analytik sind im Anhang A-C aufgeführt

Active tectonics in the NW-German Basin: Evidence from correlations between the modern landscape and deep geological structures (Lower Saxony, river Hunte)

KurzfassungIm Einzugsgebiet der Hunte (NW-Deutsches Becken, Niedersachsen) wurde untersucht, ob die Landschaftsgenese durch tektonische Bewegungen der Oberkruste beeinflußt ist. Krustenbewegungen führten im Bereich einer Hauptschollengrenze zu einer Hebung der weichselzeitlichen Niederterrasse (durchschnittliche Hebungssrate von ~0,5 mm/a über die letzten 12000 Jahre). Tektonischer Einfluß auf die heutige Landoberfläche ist über einem permischen Salzkissen zu verzeichnen, wo sich das Gefälle der holozänen Aue umkehrt. Krustenbewegungen haben mit großer Wahrscheinlichkeit Vorzugsrichtungen verursacht, die an der Tertiärbasis und in der heutigen Landschaft nachweisbar sind (0-5° und 90-95°). Das Abfließen der Hunte nach Norden scheint durch eine aktive, nordwärts gerichtete Kippung des NW-Deutschen Beckens verursacht zu sein. Hohe lineare Korrelationskoeffizienten zwischen Tiefenlage der Tertiärbasis und Höhenlage der heutigen Landoberfläche weisen auf eine aktive Kippung des Beckens hin. Beckensubsidenz hat möglicherweise die Akkumulation der weichselzeitlichen Niederterrasse gesteuert, da eine Übereinstimmung zwischen rezenter Beckensubsidenz und durchschnittlicher Sedimentationsrate des Niederterrassenkörpers besteht. Untersuchungen an einer geschlossenen Hohlform deuten auf eine aktive Sackungsstruktur hin, da sich Anomalien des geologischen Untergrundes mit der topographischen Lage der Struktur decken.

Piattaforma off-shore : progettazione delle procedure di movement e lifting relative al lower level deck section 1 e section 2

Progettazione delle procedure necessarie alla realizzazione di piattaforme off-shore, grandi e complesse strutture intelaiate di pilastri, diagonali, travi primarie e travi secondarie, progettate per insediarsi in ambiente marino ed idonee ad ospitare impianti per l'estrazione di idrocarburi. Durante la fase di progettazione si procede con l'ideare la struttura della piattaforma fino a definire le caratteristiche di ogni componente: tale fase ha come esito la redazione dei project drawings (disegni di progetto). La fase di realizzazione è quella che interessa propriamente il lavoro svolto: a seguito della progettazione infatti emergono nuove problematiche a livello applicativo e costruttivo che necessitano di essere studiate e risolte preventivamente alla costruzione fisica dell'opera. In particolar modo è necessario definire quali parti della struttura possono essere acquistate e quali invece devono essere realizzate su misura. Definite le modalità costruttive, viene effettuato lo studio riguardante la movimentazione dei vari piani della piattaforma, movement, e successivamente le problematiche relative al sollevamento degli stessi, lifting. Le due procedure necessitano di raffinate valutazioni euristiche ed analitiche per garantire che la struttura non collassi.

International cooperation in endourology: percutaneous and flexible ureteroscopic treatment of lower pole kidney stones

Introduction Lower pole kidney stones represent at time a challenge for the urologist. The gold standard treatment for intrarenal stones <2 cm is Extracorporeal Shock Wave Lithotripsy (ESWL) while for those >2 cm is Percutaneous Nephrolithotomy (PCNL). The success rate of ESWL, however, decreases when it is employed for lower pole stones, and this is particularly true in the presence of narrow calices or acute infundibular angles. Studies have proved that ureteroscopy (URS) is an efficacious alternative to ESWL for lower pole stones <2 cm, but this is not reflected by either the European or the American guidelines. The aim of this study is to present the results of a large series of flexible ureteroscopies and PCNLs for lower pole kidney stones from high-volume centers, in order to provide more evidences on the potential indications of the flexible ureteroscopy for the treatment of kidney stones. Materials and Methods A database was created and the participating centres retrospectively entered their data relating to the percutaneous and flexible ureteroscopic management of lower pole kidney stones. Patients included were treated between January 2005 and January 2010. Variables analyzed included case load number, preoperative and postoperative imaging, stone burden, anaesthesia (general vs. spinal), type of lithotripter, access location and size, access dilation type, ureteral access sheath use, visual clarity, operative time, stone-free rate, complication rate, hospital stay, analgesic requirement and follow-up time. Stone-free rate was defined as absence of residual fragments or presence of a single fragment <2 mm in size at follow-up imaging. Primary end-point was to test the efficacy and safety of flexible URS for the treatment of lower pole stones; the same descriptive analysis was conducted for the PCNL approach, as considered the gold standard for the treatment of lower pole kidney stones. In this setting, no statistical analysis was conducted owing to the different selection criteria of the patients. Secondary end-point consisted in matching the results of stone-free rates, operative time and complications rate of flexible URS and PCNL in the subgroup of patients harbouring lower pole kidney stones between 1 and 2 cm in the higher diameter. Results A total 246 patients met the criteria for inclusion. There were 117 PCNLs (group 1) and 129 flexible URS (group 2). Ninety-six percent of cases were diagnosed by CT KUB scan. Mean stone burden was 175±160 and 50±62 mm2 for groups 1 and 2, respectively. General anaesthesia was induced in 100 % and 80% of groups 1 and 2, respectively. Pneumo-ultrasonic energy was used in 84% of cases in the PCNL group, and holmium laser in 95% of the cases in the flexible URS group. The mean operative time was 76.9±44 and 63±37 minutes for groups 1 and 2 respectively. There were 12 major complications (11%) in group 1 (mainly Grade II complications according to Clavidien classification) and no major complications in group 2. Mean hospital stay was 5.7 and 2.6 days for groups 1 and 2, respectively. Ninety-five percent of group 1 and 52% of group 2 required analgesia for a period longer than 24 hours. Intraoperative stone-free rate after a single treatment was 88.9% for group 1 and 79.1% for group 2. Overall, 6% of group 1 and 14.7% of group 2 required a second look procedure. At 3 months, stone-free rates were 90.6% and 92.2% for groups 1 and 2, respectively, as documented by follow-up CT KUB (22%) or combination of intra-venous pyelogram, regular KUB and/or kidney ultrasound (78%). In the subanalysis conducted comparing 82 vs 65 patients who underwent PCNL and flexible URS for lower pole stones between 1 and 2 cm, intreoperative stone-free rates were 88% vs 68% (p= 0.03), respectively; anyway, after an auxiliary procedure which was necessary in 6% of the cases in group 1 and 23% in group 2 (p=0.03), stone-free rates at 3 months were not statistically significant (91.5% vs 89.2%; p=0.6). Conversely, the patients undergoing PCNL maintained a higher risk of complications during the procedure, with 9 cases observed in this group versus 0 in the group of patients treated with URS (p=0.01) Conclusions These data highlight the value of flexible URS as a very effective and safe option for the treatment of kidney stones; thanks to the latest generation of flexible devices, this new technical approach seems to be a valid alternative in particular for the treatment of lower pole kidney stones less than 2 cm. In high-volume centres and in the hands of skilled surgeons, this technique can approach the stone-free rates achievable through PCNL in lower pole stones between 1 and 2 cm, with a very low risk of complications. Furthermore, the results confirm the high success rate and relatively low morbidity of modern PCNL for lower pole stones, with no difference detectable between the prone and supine position.

The influence of petrogenetic processes on the composition of Ocean Island Basalts

Ocean Island Basalts (OIB) provide important information on the chemical and physical characteristics of their mantle sources. However, the geochemical composition of a generated magma is significantly affected by partial melting and/or subsequent fractional crystallization processes. In addition, the isotopic composition of an ascending magma may be modified during transport through the oceanic crust. The influence of these different processes on the chemical and isotopic composition of OIB from two different localities, Hawaii and Tubuai in the Pacific Ocean, are investigated here. In a first chapter, the Os-isotope variations in suites of lavas from Kohala Volcano, Hawaii, are examined to constrain the role of melt/crust interactions on the evolution of these lavas. As 187Os/188Os sensitivity to any radiogenic contaminant strongly depend on the Os content in the melt, Os and other PGE variations are investigated first. This study reveals that Os and other PGE behavior change during the Hawaiian magma differentiation. While PGE concentrations are relatively constant in lavas with relatively primitive compositions, all PGE contents strongly decrease in the melt as it evolved through ~ 8% MgO. This likely reflects the sulfur saturation of the Hawaiian magma and the onset of sulfide fractionation at around 8% MgO. Kohala tholeiites with more than 8% MgO and rich in Os have homogeneous 187Os/188Os values likely to represent the mantle signature of Kohala lavas. However, Os isotopic ratios become more radiogenic with decreasing MgO and Os contents in the lavas, which reflects assimilation of local crust material during fractional crystallization processes. Less than 8% upper oceanic crust assimilation could have produced the most radiogenic Os-isotope ratios recorded in the shield lavas. However, these small amounts of upper crust assimilation have only negligible effects on Sr and Nd isotopic ratios and therefore, are not responsible for the Sr and Nd isotopic heterogeneities observed in Kohala lavas. In a second chapter, fractional crystallization and partial melting processes are constrained using major and trace element variations in the same suites of lavas from Kohala Volcano, Hawaii. This inverse modeling approach allows the estimation of most of the trace element composition of the Hawaiian mantle source. The calculated initial trace element pattern shows slight depletion of the concentrations from LREE to the most incompatible elements, which indicates that the incompatible element enrichments described by the Hawaiian melt patterns are entirely produced by partial melting processes. The “Kea trend” signature of lavas from Kohala Volcano is also confirmed, with Kohala lavas having lower Sr/Nd and La/Th ratios than lavas from Mauna Loa Volcano. Finally, the magmatic evolution of Tubuai Island is investigated in a last chapter using the trace element and Sr, Nd, Hf isotopic variations in mafic lava suites. The Sr, Nd and Hf isotopic data are homogeneous and typical for the HIMU-type OIB and confirms the cogenetic nature of the different mafic lavas from Tubuai Island. The trace element patterns show progressive enrichment of incompatible trace elements with increasing alkali content in the lavas, which reflect progressive decrease in the degree of partial melting towards the later volcanic events. In addition, this enrichment of incompatible trace elements is associated with relative depletion of Rb, Ba, K, Nb, Ta and Ti in the lavas, which require the presence of small amount of residual phlogopite and of a Ti-bearing phase (ilmenite or rutile) during formation of the younger analcitic and nephelinitic magmas.

Ophiolites of the eastern Vardar Zone, N. Greece

In the present thesis, the geochemistry, petrology and geochronology of ophiolite complexes from central northern Greece were studied in detail in order to gain insights on the petrogenetic pathways and geodynamic processes that lead to their formation and evolution. The major- and trace-element content of minerals and whole rocks from all four ophiolite complexes was determined using high-precision analytical equipment. These results were then coupled with Nd and Sr isotopic measurements. In order to precisely place the evolution of these ophiolites in time, U-Pb geochronology on zircons was conducted using a SHRIMP-II. The data obtained suggest that the ophiolites studied invariably show typical characteristics of subduction-zone magmatism (e.g. negative Nb anomalies, Th enrichment). In N-MORB-normalised multielement profiles the high field-strength elements display patterns that vary from depleted to N-MORB-like. Chondrite-normalised rare-earth element (REE) profiles show flat heavy-REE patterns suggesting a shallow regime of source melting for all the ophiolites, well within the stability field of spinel lherzolite. The majority of the samples have light-REE depleted patterns. 87Sr/86Sr isotopic ratios range from 0.703184 to 0.715853 and are in cases influenced by alteration. The εNd values are positive (the majority of the mafic samples is typically 7.1-3.1) but lower than N-MORB and depleted mantle. With the exception of the Thessaloniki ophiolite that has uniform island-arc tholeiitic chemical characteristics, the rest of the ophiolites show dual chemistry consisting of rocks with minor subduction-zone characteristics that resemble chemically back-arc basin basalts (BABB) and rocks with more pronounced subduction-zone characteristics. Tectonomagmatic discrimination schemes classify the samples as island-arc tholeiites and back-arc basin basalts or N-MORB. Melting modelling carried out to evaluate source properties and degree of melting verifies the dual nature of the ophiolites. The samples that resemble back-arc basin basalts require very small degrees of melting (<10%) of fertile sources, whereas the rest of the samples require higher degrees (25-15%) of melting. As deduced from the present geochemical and petrological investigation, the ophiolites from Guevguely, Oraeokastro, Thessaloniki, and Chalkidiki represent relics of supra-subduction zone crust that formed in succeeding stages of island-arc rifting and back-arc spreading as well as in a fore arc setting. The geochronological results have provided precise determination of the timing of formation of these complexes. The age of the Guevguely ophiolite has been determined as 167±1.2 Ma, that of Thessaloniki as 169±1.4 Ma, that of Kassandra as 167±2.2 Ma and that of Sithonia as 160±1.2 Ma.