bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of body fatness measurements by near-infrared reactance and dual-energy X-ray absorptiometry in normal-weight and obese black and white women
Authors: Jennings Courtney L. , Micklesfield Lisa K. , Lambert Mike I. , Lambert Estelle V. , Collins Malcolm , Goedecke Julia H.
Published: November 2009

The aim of the present study was to compare body fat percent (BF %) using single-site near-IR reactance (NIR) and dual-energy X-ray absorptiometry (DXA) in a cohort of normal-weight (BMI < 25 kg/m2) black (n 102) and white (n 71); and obese (BMI ≥ 30 kg/m2) black (n 117) and white (n 41) South African women (18–45 years). NIR-derived BF % was significantly correlated with DXA-derived BF % in all groups: normal-weight black (r 0·55, 95 % CI: 0·40, 0·67, P < 0·001) and white (r 0·69, 95 % CI: 0·53, 0·79, P < 0·001) women; obese black (r 0·59, 95 % CI: 0·46, 0·70, P < 0·001) and white (r 0·56, 95 % CI: 0·30, 0·74, P < 0·001) women. NIR under-predicted BF% compared to DXA in black women (normal-weight, − 4·36 (sd 4·13) % and obese, − 3·41 (sd 3·72) %), while smaller mean differences were observed in white women (normal-weight, − 0·29 (sd 4·19) % and obese, − 0·81 (sd 3·09) %), irrespective of normal-weight or obese status (P < 0·001). In obese subjects, NIR-derived BF % did not measure values greater than approximately 45 %, while the maximum DXA-derived measure was 58 %. In conclusion, although there was a significant relationship between NIR- and DXA-derived BF %, NIR under-predicted BF % in normal-weight and obese black South African women compared to DXA, but to a greater extent in subjects with very high levels of adiposity (>45 %). The results of single-site NIR as a measure of BF % should therefore be interpreted with caution, particularly in women of African descent and in those with very high levels of adiposity.
Protolith age and provenance of metasedimentary rocks in Variscan allochthon units: U–Pb SHRIMP zircon data from the Orlica–Śnieżnik Dome, West Sudetes
Authors: JASTRZĘBSKI MIROSŁAW , ŻELAŹNIEWICZ ANDRZEJ , NOWAK IZABELLA , MURTEZI MENTOR , LARIONOV ALEXANDER N.
Published: November 2009

New U–Pb sensitive high-mass resolution ion microprobe (SHRIMP) data from detrital zircons within the Orlica–Śnieżnik Dome provide new insights into the stratigraphic and palaeogeographic position of assumed relict Precambrian basement preserved in the Variscan collisional orogen of the West Sudetes, SW Poland. Hitherto, the Młynowiec Formation and the Stronie Formation within the Orlica–Śnieżnik Dome were assumed to represent two metavolcano-sedimentary successions of Proterozoic and early Palaeozoic age, respectively. However, when previous U–Pb data and mapping data from the Orlica–Śnieżnik Dome are combined with the new detrital zircon isotopic ages both from paragneisses within the Młynowiec Formation and from light-coloured quartzites and mica schists within the Stronie Formation, the result strongly suggests that the protoliths of these two formations actually form a continuous succession. This continuous succession is herein designated the Młynowiec–Stronie Group. The rocks of this group were deposited during middle Cambrian–early Ordovician times (c.520–470 Ma), presumably at the northern edge of West Gondwana after the 10–20 Ma period of tectonic quiescence that followed the terminal stage of the Cadomian collisions. Monotonous Młynowiec metagreywackes form the lower part of the succession, and the lithologically diverse schistose Stronie Formation forms its upper part. The change from greywacke (Młynowiec) to volcano-sedimentary (Stronie) facies coincided with the onset of rather short-lived volcanic activity which climaxed around 505–495 Ma and which supplied the volcanogenic components to the Stronie Formation. No ‘Cadomian unconformity’ has been observed in the region. Xenocrystic zircons from the Młynowiec–Stronie Group retain records of Archaean (3.0–2.3 Ga), Palaeoproterozoic (2.1–1.8 Ga) and Neoproterozoic to early Cambrian (660–530 Ma) zircon-forming events. These zircon ages, together with the lack of 1.7–1.2 Ga zircon ages, suggest that the source areas for the metasedimentary rocks may have been the West Africa craton, which therefore differs from the Amazonian affinity of the adjacent Brunovistulia Terrane. Nevertheless, two zircons,c.1.0 and 1.1 Ga old, respectively, indicate that the Młynowiec–Stronie Group sedimentary basin must have still been within the delivery reach of detritus ultimately derived from the Grenvillian-age belt(s). The detrital components of the supracrustal formations of the Orlica–Śnieżnik Dome were mainly derived from Neoproterozoic zircon-bearing crystalline rocks that were accreted to, and included in, the Cadomian basement in several intrusive pulses that culminated at 660–640 Ma, 620 Ma and 570–530 Ma.
Motion of a drop along the centreline of a capillary in a pressure-driven flow
Authors: LAC ETIENNE , SHERWOOD J. D.
Published: November 2009

The deformation of a drop as it flows along the axis of a circular capillary in low Reynolds number pressure-driven flow is investigated numerically by means of boundary integral computations. If gravity effects are negligible, the drop motion is determined by three independent parameters: the size a of the undeformed drop relative to the radius R of the capillary, the viscosity ratio λ between the drop phase and the wetting phase and the capillary number Ca, which measures the relative importance of viscous and capillary forces. We investigate the drop behaviour in the parameter space (a/R, λ, Ca), at capillary numbers higher than those considered previously. If the fluid flow rate is maintained, the presence of the drop causes a change in the pressure difference between the ends of the capillary, and this too is investigated. Estimates for the drop deformation at high capillary number are based on a simple model for annular flow and, in most cases, agree well with full numerical results if λ ≥ 1/2, in which case the drop elongation increases without limit as Ca increases. If λ < 1/2, the drop elongates towards a limiting non-zero cylindrical radius. Low-viscosity drops (λ < 1) break up owing to a re-entrant jet at the rear, whereas a travelling capillary wave instability eventually develops on more viscous drops (λ > 1). A companion paper (Lac & Sherwood, J. Fluid Mech., doi:10.1017/S002211200999156X) uses these results in order to predict the change in electrical streaming potential caused by the presence of the drop when the capillary wall is charged.
Axisymmetric dynamics of a bubble near a plane wall
Authors: VAN DER GELD C. W. M. , KUERTEN J. G. M.
Published: November 2009

Explicit expressions for the added mass tensor of a bubble in strongly nonlinear deformation and motion near a plane wall are presented. Time evolutions and interconnections of added mass components are derived analytically and analysed. Interface dynamics have been predicted with two methods, assuming that the flow is irrotational, that the fluid is perfect and with the neglect of gravity. The assumptions that gravity and viscosity are negligible are verified by investigating their effects and by quantifying their impact in some cases of strong deformation, and criteria are presented to specify the conditions of their validity. The two methods are an analytical one and the boundary element method, and good agreement is found. It is explained why a strongly deforming bubble is decelerated. The classical Rayleigh–Plesset equation is extended with terms to account for arbitrary, axisymmetric deformation and to account for the proximity of a wall. An expression for the corresponding cycle frequency that is valid in the vicinity of the wall is derived. An equation similar to the Rayleigh–Plesset equation is presented for the most important anisotropic deformation mode. Well-known expressions for the angular frequencies of some periodic solutions without a wall follow easily from the equations presented. A periodically deforming bubble without initial velocity of the centroid and without a dominating isotropic deformation component is eventually always driven towards the wall. A simplified equation of motion of the centre of a deforming bubble is presented. If desired, full deformation computations can be speeded up by selecting an artificially low value of the polytropic constantCp/Cv.
Dynamic electric-field-induced response of charged spherical colloids in uncharged hydrogels
Authors: WANG MU , HILL REGHAN J.
Published: November 2009

Embedding colloidal particles in polymeric hydrogels often endows the polymer skeleton with appealing characteristics for microfluidics and biosensing applications. This theoretical study provides a rigorous foundation for interpreting active electrical microrheology and electroacoustic experiments on such materials. In addition to viscoelastic properties of the composites, these techniques sense physicochemical characteristics of the particle–polymer interface. Wang & Hill (Soft Matter, vol. 4, 2008, p. 1048) studied the steady response of a rigid, impenetrable sphere in a compressible hydrogel skeleton. Here, we extend their analysis to arbitrary frequencies, showing, in general, how the frequency response depends on the particle size and charge, ionic strength of the electrolyte and elastic and hydrodynamic characteristics of the polymer skeleton. Our calculations capture the transition from quasi-steady compressible to quasi-steady incompressible dynamics as the frequency passes through the reciprocal draining time of the gel. Above the reciprocal draining time, the skeleton and fluid move in unison, so the dynamics are incompressible and, thus, given to an excellent approximation by the well-known dynamic electrophoretic mobility but with the Newtonian shear viscosity replaced by a complex, frequency-dependent value.
Mantis shrimps Rissoides desmaresti in Tremadog Bay, North Wales
Authors: Ramsay Kirsten , Holt Rohan H.F.
Published: November 2009

In 1999 divers discovered a population of the burrowing mantis shrimp Rissoides (Meiosquilla) desmaresti (Crustacea: Stomatopoda) east of the St Tudwal's Islands, North Wales. This species has only sporadically been recorded in UK waters and commonly occurs in the Mediterranean. In summer 2000 the burrow morphology and distribution of these shrimps in the area east of the St Tudwal's Islands was investigated. Burrows were found at ten of the 15 sites investigated in a survey area measuring ∼18 km2. Burrow density varied from one to 11 burrows per 100 m2. The burrows were always recorded in sediments consisting of a mixture of mud, sand and gravel but were not present at sites with a high proportion of mud (>70%) or sandy sediments with very little mud ([les ]2%). Resin casts of six burrows revealed that these have a simple elongated U-shape, with an average length of ∼450 mm and depth of ∼160 mm. The average diameter of the burrow entrance was 19±2 mm and the diameter of the burrow along the horizontal section varied between 18 and 38 mm with a distinct constriction part way along.
Epidemiology and associated factors for nosocomial methicillin-resistant Staphylococcus aureus infection in a tertiary-care hospital
Authors: SACAR S. , SAYIN KUTLU S. , TURGUT H. , CEVAHIR N. , HIRCIN CENGER D. , TEKIN K.
Published: November 2009

We analysed nosocomial MRSA cases between January 2004 and December 2006 in a retrospective case-control study in a 250-bed tertiary-care teaching hospital. During the study period, 265 nosocomial Staphylococcus aureus infections were identified in 231 patients. There was a significant increase in methicillin resistance in isolates (MRSA) from these infections with frequencies for 2004 of 39/88 (44·3%), 2005 (62/80, 77·5%), and 2006 (75/97, 77·3%) (P<0·001). Multivariate analysis showed that associated factors for nosocomial MRSA infection were prolonged hospitalization (OR 3·982, 95% CI 2·235–7·094, P<0·001), mechanical ventilation (OR 3·052, 95% CI 1·666–5·590, P<0·001), surgical operation (OR 2·032, 95% CI 1·102–3·748, P=0·023), and male sex (OR 2·000, 95% CI 1·081–3·699, P=0·027). The determination of associated factors for methicillin resistance in nosocomial S. aureus infections in hospitals will play an important role in efforts to reduce MRSA infection rates.
Delayed wound healing in elderly people
Authors: Thomason Helen A. , Hardman Matthew J.
Published: November 2009

Our ability to heal wounds deteriorates with age, leading in many cases to a complete lack of repair and development of a chronic wound. Moreover, as the elderly population continues to grow the prevalence of non-healing chronic wounds is escalating. Cutaneous wound repair occurs through a combination of overlapping phases, including an initial inflammatory response, a proliferative phase and a final remodelling phase. In elderly subjects the inflammatory response is delayed, macrophage and fibroblast function compromised, angiogenesis reduced and re-epithelialization inhibited. Whilst a large body of historic research describes the defective processes that lead to delayed healing, only recently have the molecular mechanisms by which these defects arise begun to be elucidated. Current therapies available for treatment of chronic wounds in elderly people are surprisingly limited and generally ineffective. Thus there is an urgent need to develop new therapeutic strategies based on these recent molecular and cellular insights.
Small-scale seed-bank patterns in a forest soil
Authors: Plue Jan , Goyens Geertrui , Van Meirvenne Marc , Verheyen Kris , Hermy Martin
Published: November 2009

The forest seed bank has been demonstrated to vary spatially at scales from 2 to 10 m. To our knowledge, the fine-scale spatial structure, i.e. < 2 m, has not been studied before. This study aims to make a thorough investigation of fine-scale spatial structure. Soil samples (128) were collected from each of five 2.1 m × 2.1 m plots, using a combined systematic (64) and random design (64). This allowed investigation of the fine-scale spatial structure of individual species–plot combinations using indicator-variograms. Our results indicated that over half of all species recorded in a particular plot were spatially structured. Remarkably, the presence of spatial structure seemed independent of species frequency. Visualization of the spatial structure showed an irregular spatial pattern, i.e. seed clusters that were randomly distributed in space. Spatial dependence occurred over small distances, possibly suggesting that a significant proportion of seeds was deposited near the mother plant. We conclude by presenting the relevance and implications of small-scale spatial seed-bank patterning for seed-bank sampling.
Random Sampling of Plane Partitions
Authors: BODINI OLIVIER , FUSY ÉRIC , PIVOTEAU CARINE
Published: November 2009

This article presents uniform random generators of plane partitions according to size (the number of cubes in the 3D interpretation). Combining a bijection of Pak with the method of Boltzmann sampling, we obtain random samplers that are slightly superlinear: the complexity isO(n(lnn)3) in approximate-size sampling andO(n4/3) in exact-size sampling (under a real-arithmetic computation model). To our knowledge, these are the first polynomial-time samplers for plane partitions according to size (there exist polynomial-time samplers of another type, which draw plane partitions that fit inside a fixed bounding box). The same principles yield efficient samplers for (a×b)-boxed plane partitions (plane partitions with two dimensions bounded), and for skew plane partitions. The random samplers allow us to perform simulations and observe limit shapes and frozen boundaries, which have been analysed recently by Cerf and Kenyon for plane partitions, and by Okounkov and Reshetikhin for skew plane partitions.
Interpersonal Processes and Hearing Voices: A Study of the Association Between Relating to Voices and Distress in Clinical and Non-Clinical Hearers
Authors: Sorrell Eleanor , Hayward Mark , Meddings Sara
Published: November 2009

Background:Previous research suggests that the distress experienced by clinical voice hearers is associated with the perceived relationship between voice and hearer, independent of beliefs about voices and depression.Aims:This study aimed to replicate these findings and generate further hypotheses by comparing the voice hearing experiences of clinical and non-clinical hearers.Method:A cross-sectional, quantitative design was employed and used between-subjects and correlational methods. Thirty-two clinical voice hearers and 18 non-clinical voice hearers were assessed using the PSYRATS, the Voice and You questionnaire, the Beliefs About Voices Questionnaire – Revised, and the Beck Depression Inventory-II.Results:For clinical voice hearers, distress was significantly associated with perceptions of the voice as dominating and intrusive, and hearers distancing themselves from the voice. However, these associations were not independent of beliefs about voices’ omnipotence or malevolence. Non-clinical voice hearers were significantly less distressed than clinical voice hearers and voices were perceived as less dominant, intrusive, malevolent and omnipotent. Non-clinical hearers were found to relate from a position of less distance to voices perceived as benevolent.Conclusions:Findings from previous research were only partially replicated. Clinically, the development of less maladaptive relationships between voice and voice hearer may reduce distress.
The mobility transition revisited, 1500–1900: what the case of Europe can offer to global history
Authors: Lucassen Jan , Lucassen Leo
Published: November 2009

Historians of migration have increasingly criticized the idea of a ‘mobility transition’, which assumed that pre-modern societies in Europe were geographically fairly immobile, and that people only started to move in unprecedented ways with the onset of modernization in the nineteenth century. In line with this critique, this article attempts to apply thorough quantitative tests to the available data. The focus is on ‘cross-community migration’, following Patrick Manning's argument that migrants moving over a cultural border are most likely to accelerate the rate of innovation. Six forms of migration are considered: emigration out of Europe, immigration from other continents, rural colonization of ‘empty spaces’, movements to large cities, seasonal migration, and the movement of sailors and soldiers. To illustrate regional variations, the examples of the Netherlands and Russia are contrasted. The reconstruction presented here is partial and preliminary, but it unequivocally shows that early modern Europe was much more mobile than modernization scholars allowed for. There was indeed a sharp increase in the level of migration after 1850, but it was due to improvements in transport rather than to modernization in a more general sense. This model has been elaborated for Europe but it can also be applied to other parts of the world and can hopefully contribute to the debate on the ‘Great Divergence’ between Europe and Asia.
State formation and urbanization trajectories: state finance in the Ottoman Empire before 1800, as seen from a Dutch perspective
Authors: Fritschy Wantje
Published: November 2009

Looking at state finance in the Ottoman Empire from a Dutch perspective shows remarkable differences between the two systems. This article suggests that these differences were related to the fact that, in contrast to those in the Ottoman Empire, fiscal systems in western Europe, and especially in the Netherlands, developed within a context of economy-driven rather than state-driven trajectories of urbanization. This gave rise to separate systems of urban public finance, which enhanced possibilities for funding a debt serviced by indirect urban taxes, the root of later state debts. In Ottoman cities, systems of urban public finance managed by urban governments did not develop, thus precluding a similar development.
Historical globalization and colonial legal culture: African assessors, customary law, and criminal justice in British Africa
Authors: Ibhawoh Bonny
Published: November 2009

The idea of globalization has helped to rehabilitate universalizing categories, such as colonialism and cosmopolitanism, criticized for their tendency to ignore the differences between local cultures and the operation of power. Drawing on the burgeoning discussion on historical globalization, and focussing on the role of African assessors, this article examines how colonial courts grappled with the tension between the aspiration toward imperial legal universalism and the ‘Othering’ of African subjects. It argues that British colonialism in Africa represented a form of globalization of English law, generating a ‘centripetal jurisprudence’ that sought to square the inequities of an engagement with local custom by holding up the values of justice, equity, and conscience. Imperial legal universalism required both the accommodation and containment of African difference. The paradox of integration and differentiation in colonial constructions of globality is that imperial power and local cultures were not always in conflict, but were sometimes complementary and mutually reinforcing.
Reflections on the transnational turn in United States history: theory and practice
Authors: Tyrrell Ian
Published: November 2009

This article situates the idea of ‘transnational history’ within the recent historiography of the United States, as both a reaction against and accommodation to the nation-state focus of that historiography. It explains transnational history's specific American development as a broad project of research to contextualize US history and decentre the nation; it explores the conditions of American historical practice that influenced the genesis and growth of this version of transnational history; and it compares the concept with competitor terms such as international history, comparative history, global history, histoire croisée,and trans-border. In the United States, transnational history came to be considered complementary to these concepts in its commitment to render American historiography less parochial, yet, because of its origins, the concept has remained limited in application by period and spatial scope. While the concept retains utility because of its specific research programme to denaturalize the nation, transnational history understood as an exploration of ‘transnational spaces’ opens possibilities for an approach of more general historiographical relevance.
Hypertonie und Salz
Authors: Bock Andreas
Published: November 2009

Die Druck-Natriurese-Kurve der Niere bestimmt das Langzeitniveau des arteriellen Blutdrucks. Sämtliche bekannten (erworbenen und genetischen) Hypertonie-Ursachen lassen sich mit Veränderungen dieser Kurve erklären. Aus diesem Grund ist Verminderung der Salzzufuhr eine wirksame Maßnahme zur Senkung des Blutdrucks. Gesundheitspolitisch wäre eine Reduktion des Kochsalzgehalts von verarbeiteten Lebensmitteln eine hochwirksame und kosteneffektive Maßnahme zur Reduktion der kardiovaskulären Morbidität, die jedoch auf Widerstand von Seiten der interessierten Industrie stößt. Reduktion der Kochsalzzufuhr auf unter 100 mmol / Tag (6 g NaCl) senkt den Blutdruck und verstärkt die Wirkung fast aller antihypertensiven Medikamente. Sie kann in manchen Fällen durch Verzicht aufs Zusalzen erzielt werden, in anderen ist eine fachgerechte Diätberatung sinnvoll. Salzreduktion vermindert den Durst, was mit der (unbegründeten) Gesundheitsempfehlung zum Trinken von 2 – 3 Litern Wasser täglich in Widerspruch geraten kann.
Welche Diuretikakombinationen sind sinnvoll?
Authors: Fuster Daniel
Published: November 2009

Diuretika werden immer dann eingesetzt, wenn der Gehalt von Natrium und Wasser im Extrazellulärraum des Körpers vermindert werden soll. In zwei klinischen Situationen macht es Sinn, Diuretika verschiedener Klassen zu kombinieren: Entweder ist die Wirkung eines Diuretikums alleine ungenügend oder die Nebenwirkung eines Diuretikums soll durch die Addition eines zweiten Diuretikums einer anderen Substanzklasse abgeschwächt werden. Im klinischen Alltag wird letzteres besonders bei der Schleifen- oder Thiaziddiuretika-induzierten Hypokaliämie durch Kombination mit kaliumsparenden Diuretika ausgenützt. Unerlässlich für eine sinnvolle Kombination von Diuretika sind Kenntnisse der Pharmakokinetik und Wirkungsmechanismen der eingesetzten Diuretika.
Copeptin – diagnostischer Parameter, Biomarker, beides?
Authors: Rutishauser Jonas
Published: November 2009

Copeptin ist ein Fragment des Vorläuferproteins des antidiuretischen Hormons (ADH). Zirkulierende Copeptinspiegel reflektieren die Aktivität des ADH-Systems. Die Bestimmung stimulierter ADH-Plasmaspiegel wird zur Differentialdiagnostik partieller Diabetes insipidus-Formen benötigt und ist hilfreich zur Diagnose der primären Polydipsie. Die Messung des ADH ist jedoch technisch anspruchsvoll, und validierte Assays sind für die Routinediagnostik nicht verfügbar. Vor einigen Jahren ist eine zuverlässige Methode zur Messung von Copeptin entwickelt worden, welche in Zukunft die ADH-Bestimmung in der klinischen Diagnostik des Diabetes insipidus ersetzen kann und die Abklärung der Hyponatriämie potentiell erleichtert. ADH und Copeptin werden auch bei einer Vielzahl von akuten Erkrankungen wie Sepsis, Schock, Pneumonie, Myokardinfarkt oder akut exazerbierter COPD im Rahmen einer Stressreaktion freigesetzt. Eine Reihe von klinischen Studien bei solchen Krankheiten haben die Rolle von Copeptin als prognostisch relevanter Biomarker belegt. Der Copeptin-Assay ist derzeit noch nicht kommerziell erhältlich.
Vaptane und Herzinsuffizienz
Authors: Haass Markus
Published: November 2009

Vasopressin ist für die Blutdruck-, Volumen- und Osmoregulation von physiologischer Bedeutung. Potentielle Folgen einer inadäquaten Vasopressin-Freisetzung bei Herzinsuffizienz können unter anderem eine unphysiologische Flüssigkeitsretention sowie eine Hyponatriämie sein. Vaptane sind nicht-peptidische Vasopressin-Rezeptorantagonisten mit unterschiedlicher Selektivität gegenüber drei in unterschiedlichen Geweben exprimierten Vasopressin-Rezeptoren, den sogenannten V1a- (→ Vasokonstriktion), V1b- (→ unter anderem ACTH-Freisetzung) und V2-Rezeptoren (→ Hemmung der freien Wasserrückresorption in der Niere). Selektive V2- (Lixivaptan, Satavaptan und Tolvaptan) und nicht-selektive V1a/V2-Rezeptorblocker (Conivaptan) erlauben bei hydropischer kardialer Dekompensation eine raschere Gewichtsabnahme und eine schnellere symptomatische Besserung als unter Standardtherapie. Über Inhibition der freien Wasserrückresorption ermöglichen Vaptane bei euvolämer und hypervolämer Hyponatriämie eine kontrollierte Normalisierung des Serum-Natriums. Vaptane werden gut vertragen und haben – im Gegensatz zu Diuretika – keinen negativen Einfluß auf Nierenfunktion und Serumkalium. Herzfrequenz und Blutdruck werden durch die genannten Vaptane nicht beeinflusst. Trotz der exzellenten Akut-Wirkung ergab sich für Tolvaptan in der an über 4000 Patienten mit Herzinsuffizienz durchgeführten EVEREST-Studie kein prognostischer Nutzen während einer Langzeitbehandlung über im Mittel 9,9 Monate.
„Cross-talk“ zwischen Herz und Niere – das Kardiorenale Syndrom und seine Therapie aus der Sicht des Nephrologen
Authors: Farese Stefan
Published: November 2009

Herz und Nierenfunktion sind eng miteinander verknüpft. Ein Großteil der Patienten mit chronischer Herzinsuffizienz leidet gleichzeitig an einer Nierenfunktionsstörung. Diese ist kausal an der Entwicklung der Herzinsuffizienz beteiligt und stellt damit einen wichtigen prognostischen Faktor dar. Pathophysiologisch kommt es durch die verminderte renale Perfusion zu einer Aktivierung verschiedener Regelkreise, die eine Salz- und Wasserretention induzieren und damit das Fortschreiten der Herzinsuffizienz begünstigen. Therapeutische Ziele sind die Euvolämie sowie die kontrollierte Behandlung mittels prognostisch relevanter, kardialer Begleitmedikation. Können diese beiden Ziele aufgrund von Therapieresistenz, progredienter Niereninsuffizienz oder Therapie-Nebenwirkungen nicht erreicht werden, ist die Indikation für ein Nierenersatzverfahren gegeben. Prinzipiell können alle heute verfügbaren Verfahren angewendet werden. Die Auswahl der Modalität sollte jedoch an die individuelle Situation des Patienten angepasst und interdisziplinär besprochen werden. Obwohl sich unter Therapie bei allen Nierenersatzverfahren funktionelle und subjektive Verbesserungen nachweisen lassen, ist deren Einfluss auf die Langzeitprognose ungeklärt.
Therapie von Aszites, Hyponatriämie und hepatorenalem Syndrom bei der Leberzirrhose
Authors: Ackermann Daniel
Published: November 2009

Aszites und Hyponatriämie sind häufige Komplikationen der fortgeschrittenen Leberzirrhose. Aszites entsteht durch eine pathologisch erhöhte Natriumretention in den Nieren, welche zu einer Expansion des Extrazellulärvolumens und zur Flüssigkeitsansammlung im Peritonealraum führt. Durch die verminderte Fähigkeit der Nieren, freies Wasser zu eliminieren, kommt es zu einer hypervolämen Hyponatriämie. Die genaue Pathogenese der Natriumretention ist unklar, währenddem die Hyponatriämie durch eine Hypersekretion des antidiuretischen Hormons (Vasopressin) aus der Neurohypophyse zustande kommt. Es gibt Hinweise darauf, dass die Hyponatriämie bei Leberzirrhotikern die Entwicklung der hepatischen Enzephalopathie begünstigt. Das hepatorenale Syndrom wird durch eine ausgeprägte Vasokonstriktion der Nierenarterien verursacht. Die Behandlung des Aszites erfolgt je nach Schweregrad mit kaliumsparenden Diuretika, Schleifendiuretika und/oder Parazentese. Die Behandlung der Hyponatriämie mittels Flüssigkeitsrestriktion ist häufig unbefriedigend. Aktuell wird eine neue Familie von Vasopressinantagonisten, die sogenannten Vaptane, für das Management dieser Erkrankung evaluiert. Weil lang dauernde Studien fehlen, sind sie noch nicht für die Behandlung von Leberzirrhotikern zugelassen. Die Behandlung des hepatorenalen Syndroms ist die Lebertransplantation. Als Brücke bis zur Transplantation kann eine Therapie mit intravenösem Albumin und dem Vasopressinanalogon Terlipressin erfolgen.
Hypernatriämie – wie weiter?
Authors: Vogt Bruno , Berwert Lorenzo , Burnier Michel
Published: November 2009

Hypernatriämie bezeichnet eine über die Norm erhöhte Natriumkonzentration im Serum. Die Ursache einer Hypernatriämie ist häufig ein Wassermangel bei vermindertem Durstgefühl oder mangelnder exogener Wasserzufuhr. In seltenen Fällen kann eine Hypernatriämie durch eine erhöhte Natriumzufuhr entstehen. Schwere Hypernatriämien sind gefährlich und können bleibende Schäden hervorrufen. Bedrohliche Hypernatriämien können schon im frühen Kindesalter auftreten. Bei Erwachsenen und sehr alten Patienten ist besonders auf Medikamente zu achten, welche das Durstgefühl beeinflussen und somit Ursache einer Hypernatriämie sein können. Der Spitalaufenthalt selbst ist ein begünstigender Faktor für das Auftreten einer Hypernatriämie. Die Therapie besteht in der Korrektur der Ursache und im gezielten Volumen- und Elektrolyt- Management.
Kongenitaler nephrogener Diabetes insipidus – Fallbericht und Diskussion
Authors: Solcà Curzio , Kruse Anja
Published: November 2009

Die Krankengeschichte eines Patienten mit angeborenem renalen Diabetes insipidus wird dargestellt. Die Pathogenese und therapeutischen Modalitäten werden diskutiert.
Distribution of dissolved organic nutrients and their effect on export production over the Atlantic Ocean
Authors: Torres‐Valdés S. , Roussenov V. M. , Sanders R. , Reynolds S. , Pan X. , Mather R. , Landolfi A. , Wolff G. A. , Achterberg E. P. , Williams R. G.
Published: November 2009

A synthesis is provided of dissolved organic nitrogen (DON) and phosphorus (DOP) distributions over the Atlantic Ocean based upon field data from eight recent transects, six meridional between 50°N and 50°S and two zonal at 24° and 36°N. Over the entire tropical and subtropical Atlantic, DON and DOP provide the dominant contributions to total nitrogen and phosphorus pools for surface waters above the thermocline. Elevated DON and DOP concentrations (>5 and >0.2 μmol L−1, respectively) occur in surface waters on the eastern side of the North Atlantic subtropical gyre and equatorial sides of both the North and South Atlantic subtropical gyres, while particularly low concentrations of DOP (<0.05 μmol L−1) occur over the northern flank of the North Atlantic subtropical gyre along 36°N. This distribution is consistent with organic nutrients formed at the gyre margins supporting carbon export as they are redistributed via the gyre circulation. The effect of DON and DOP transport and cycling on export production is examined in an eddy‐permitting, coupled physical and nutrient model integrated for 40 years: organic nutrients are produced in the upwelling zones off North Africa and transferred laterally into the gyre interior, facilitated in part by the mesoscale eddy circulation, as well as fluxed northward from the tropics as part of the overturning circulation. Inputs of semilabile DON and DOP to the tropical and subtropical Atlantic Ocean play an important role in sustaining up to typically 40 and 70% of the modeled particulate N and P export, particularly on the eastern and equatorward sides of the subtropical gyres.
Magmatic processes in the Alaska subduction zone by combined 3‐D b value imaging and targeted seismic tomography
Authors: van Stiphout T. , Kissling E. , Wiemer S. , Ruppert N.
Published: November 2009

We combine two complementary seismological methods to study the deep roots of arc volcanism in the Alaskan subduction zone: targeted seismic body wave tomography and imaging of the relative size distribution (b value) of earthquakes. For the tomography we apply a staggered inversion scheme, starting with the minimum 1‐D velocity model, progressing to a 3‐D velocity model. Inversions are based on traveltime data from about 5500 events (1971–2002) with approximately 100,000 P and 50,000 S high‐quality arrivals, allowing us to resolve the 3‐D velocity field on a 20 × 20 km grid. For the b value imaging we have introduced a new 3‐D sampling approach to map the b values on surfaces in the Wadati‐Benioff zone (WBZ). Our b value study is based on 12,474 relocated events of magnitude of completeness ≥2.4 and depth >40 km. We observe anomalously high b values at depths around 100 km, appearing locally concentrated beneath active subduction volcanoes. We believe that these zones are associated with dehydration of the slab and subsequent magma generation. The analysis of VP/VS ratios likewise shows indications of the presence of fluids: significantly higher VP/VS ratios rising in columns from the top of the WBZ at 100 km depth below active volcanic centers. On the basis of the joint interpretation, we propose that our images track fluids from their genesis at 100 km depth at the top of the subducting plate to the bottom of the crust below volcanoes.
Multiscale waveform tomography with two‐step model parameterization
Authors: Gung Yuancheng , Hsu Ya‐Ting , Chiao Ling‐Yun , Obayashi Masayuki
Published: November 2009

In geophysical tomography, a proper model parameterization scheme for forward modeling is not necessarily a suitable one for the inversion stage, and vice versa. To take full advantage of the merits of parameterization in both stages, we propose a two‐step model parameterization approach, in which different model bases for forward computation and inversion are adopted and the basis change is achieved by applying a spatial projection directly to the sensitivity matrix. We demonstrate this approach through an experimental study of waveform tomography for the Pacific upper mantle shear wave structure using first‐orbit long‐period Rayleigh waves. In the forward modeling, a normal‐mode‐based nonlinear asymptotic coupling theory is used for the computation of the synthetics and sensitivity matrix, and the model is parameterized in terms of spherical harmonics which provide efficient analytical solutions for path integrals in the forward modeling. Prior to the inversion, the model basis of the sensitivity matrix is transformed to local functions within the study region. After mapping, only local bases around the data sampling path receive effective sensitivities. Accordingly, the computation cost in the inversion is significantly reduced. Furthermore, the two‐step model parameterization also adds flexibility to the inversion schemes. In particular, a wavelet‐based multiscale inversion is implemented, and its results are compared to simple damping solutions. The general concept and applications of the two‐step model parameterization are not restricted to the forwarding modeling technique or model parameterization schemes employed in this experimental study. This approach benefits any inverse problems wherever transformation of model bases helps to better constrain the results.
DNSC08 mean sea surface and mean dynamic topography models
Authors: Andersen Ole B. , Knudsen Per
Published: November 2009

The Danish National Space Center data set DNSC08 mean sea surface (MSS) is a new enhanced mapping of the mean sea surface height of the worlds oceans, derived from a combination of 12 years of satellite altimetry from a total of eight different satellites covering the period 1993–2004. It is the first global MSS without a polar gap including all of the Arctic Ocean by including laser altimetry from the ICESat mission. The mean dynamic topography (MDT) is the quantity that bridges the geoid and the mean sea surface constraining large‐scale ocean circulation. Here we present a new high‐resolution 1 min global MDT called DNSC08 MDT derived from the slightly smoothed difference between the DNSC08 MSS and the EGM2008 geoid. The derivation and quality control of the new DNSC08 MSS and DNSC08 MDT is presented in this paper along with suggestions for time period standardization of the MSS and MDT models. This way a consistent modeling of the interannual sea level variability is carried out before different MSS and MDT models are compared. Altimetric derived physical MSS can be converted into an “inverse barometer corrected MSS” by correcting the altimeter range for the inverse barometer effect of the atmosphere on the sea surface height. It is demonstrated that it is important to choose the right version of the MSS when comparing with hydrodynamic models and GPS measured tide gauges.
Seasonal climate modeling over the Indian Ocean by employing a 4D‐VAR coupled data assimilation approach
Authors: Mochizuki Takashi , Sugiura Nozomi , Awaji Toshiyuki , Toyoda Takahiro
Published: November 2009

We carry out the first attempt to apply an adjoint method to a coupled general circulation model (CGCM) toward enhancing a skill in seasonal climate modeling. Focusing on 10‐day mean errors of a CGCM output, we optimize the oceanic initial conditions together with the bulk adjustment factors by employing a four‐dimensional variational data assimilation approach. We perform 9‐month‐long assimilation experiments independently every 6 months between January 1990 and March 2000. When using the optimized values for the initial conditions and the adjustment factors, a set of 9‐month‐long, 10‐member ensemble simulation always displays realistic seasonal cycle and its interannual modulations over the tropical Indian Ocean (e.g., growing, mature, and decaying phases of the Indian Ocean Dipole Mode events). The optimized values of the bulk adjustment factors primarily reduce the model biases in climatological fields, while the optimization of the oceanic initial conditions largely contributes to a realistic representation of the interannual modulations of seasonal cycle. In the overlapped seasons (i.e., January–March and July–September), the ensemble mean states derived from two experiments show only slight differences in seasonal climate variations over most of the Indian Ocean. These results validate that our assimilation approach is generally effective for advancing a seasonal climate modeling and for obtaining a realistic analysis that is compatible between atmosphere and ocean.
Two‐dimensional discrete element models of debris avalanches: Parameterization and the reproducibility of experimental results
Authors: Banton J. , Villard P. , Jongmans D. , Scavia C.
Published: November 2009

Application of the discrete element method (DEM) to model avalanches of granular materials requires determining the correct geometric and rheological parameters for and between the particles as well as for the basal surface. The use of spherical (circular in 2‐D) particles enhances particle rolling, yielding excessive runout values. The solution usually adopted to correct this effect is to introduce a drag force which artificially slows down the particle velocities. The aim of this study is to test the capability of the DEM to simulate well‐controlled unsteady channelized granular flows, considering the measured properties of the particles and of the basal surface which naturally contribute to dissipate energy. We first performed a parametrical analysis on a simple 2‐D model in order to estimate the influence of particle shape, friction parameters, and restitution coefficients on the dynamics of the flow and on the deposit geometry. We then simulated three channelized laboratory experiments performed with two materials and two bed linings. Using the geometrical layout and the values of the mechanical parameters provided by the authors, we obtained a remarkable agreement between the observed and 2‐D simulated deposit shapes for the three experiments. Also, the computed mass evolution with time was very consistent with the experimental snapshots in all cases. These results highlight the capability of the DEM technique for modeling avalanche of granular material when the particle shape as well as the friction and restitution coefficients are properly considered.
On the value of lithofacies data for improving groundwater flow model accuracy in a three‐dimensional laboratory‐scale synthetic aquifer
Authors: Sakaki Toshihiro , Frippiat Christophe C. , Komatsu Mitsuru , Illangasekare Tissa H.
Published: November 2009

Improvement of the prediction accuracy of groundwater flow models has been receiving substantial attention from many researchers through the development of enhanced characterizations of the structure of subsurface lithofacies and of the distribution of hydraulic conductivity. In this study, we investigated how incorporating increasing amounts of lithofacies data into the construction of a conceptual model of aquifer heterogeneity helps to reduce prediction error and uncertainty in groundwater flow models. An approach based on both laboratory experiments and numerical simulations was tested using data from an intermediate‐scale synthetic heterogeneous aquifer. The heterogeneous aquifer consisted of five lithofacies, corresponding to five test sands. Three pumping tests were conducted and provided experimental data to perform groundwater flow model calibration and validation. The pumping tests were also simulated numerically in order to provide a series of error‐free synthetic hydraulic data sets. On the basis of Markov chains models of transition probabilities, a total of 901 random realizations of the heterogeneous distribution of lithofacies were created using varying amounts of conditioning lithofacies data sampled along randomly placed hypothetical boreholes. For each realization and for two other simplified lithofacies models, parameter estimation was performed to estimate the hydraulic conductivity of the lithofacies using the experimental and synthetic hydraulic data from the three pumping tests. The results generally showed that the use of more lithofacies data in the construction of the lithofacies realizations led to an improvement in groundwater flow model prediction accuracy. When using the error‐free synthetic hydraulic data, the calibration‐prediction error and uncertainty decreased drastically when the mean borehole spacing was on the order of twice the horizontal correlation length or less. When the experimental hydraulic data were used, this drastic improvement in the calibration‐prediction error was somewhat obscured and, in some cases, exhibited a local minimum. This local minimum, although beyond practical limits, corresponded to an optimal number of boreholes. Finally, the effect of incorporating more lithofacies data for the construction of lithofacies realizations was found to have a similar impact on the quality of model calibration and on the quality of predictive simulations conducted using the calibrated model.
Revisiting rainfall clustering and intermittency across different climatic regimes
Authors: Molini Annalisa , Katul Gabriel G. , Porporato Amilcare
Published: November 2009

One of the vexing questions in rainfall research is the role of intermittency and its nonuniversal signature in anomalous scaling functions. Whether this lack of universal behavior is due to the bursting patterns in rainfall intensity or the alternation between long dry periods and highly clustered wet phases (or both) remains an open issue. To progress on a narrower scope of this problem, the effects of intermittency originating from rainfall occurrence are first separated from rainfall intermittency induced by intensity variability. Across five climatic regimes considered here, it was shown that the rainfall occurrence process (OP) exhibits (1) a near‐constant spectral slope, (2) a near‐constant clustering exponent, and (3) a probability density function of dry phases displaying a power law behavior with an exponent β ≈ 1.5, consistent with other studies for timescales commensurate with frontal and storm systems. Also for the OP, the scaling exponents of the normalized higher order structure functions reveal an extensive monofractal scaling at all five climatic regimes. When taken together, these intersite results are suggestive that rainfall intensity modulations are the main cause of the nonuniversal anomalous scaling and not the clustering properties associated with the support. The nature of these modulations is markedly different when comparing rainfall to a familiar and often interrelated process such as scalar turbulence. In the case of turbulence, amplitude variability of scalar dissipation rates appear to mitigate the intermittency effects connected with anomalous scaling, while for rainfall series, intensity fluctuations seem to amplify them.