Hydroakustische Methoden. Möglichkeiten und Grenzen zur Langzeitüberwachung archäologischer Denkmale im Flachwasser

Hydroakustische Methoden werden oft zur Vermessung von archäologischen Fundstellen und zur Objektsuche in der Flachwasserzone von Seen und Flüssen eingesetzt. In diesem Beitrag werden die technischen Grundlagen hydroakustischer Messverfahren erläutert und eine kurze Beschreibung üblicherweise eingesetzter Mess- geräte gegeben. Anschließend zeigen wir Beispiele von Vermessungen mit unterschiedlichen Singlebeam-Echo- loten, Multibeam-Echoloten, einem Sidescan-Sonar und einem Interferometrischen Sonar. Mit den Arbeiten aus dem Bodensee, Zürichsee und dem Vierwaldstättersee werden die Möglichkeiten und Grenzen der Hydroakus- tik in der Binnengewässerarchäologie erläutert.

Persistence of ultrasound synovitis in patients with rheumatoid arthritis fulfilling the DAS28 and/or the new ACR/EULAR RA remission definitions: results of an observational cohort study.

OBJECTIVE The primary aim of the study was to evaluate whether rheumatoid arthritis (RA) patients considered to be in remission according to clinical criteria sets still had persisting ultrasound (US) synovitis. We further intended to evaluate the capacity of our US score to discriminate between the patients with a clinically active disease versus those in remission. METHODS This is an observational study nested within the Swiss Clinical Quality Management in Rheumatic Diseases (SCQM) rheumatoid arthritis cohort. A validated US score (SONAR score) based on a semi-quantitative B-mode and Doppler (PwD) score as part of the regular clinical workup by rheumatologists in different clinical settings was used. To define clinically relevant synovitis, the same score was applied to 38 healthy controls and the 90st percentile was used as cut-off for 'relevant' synovitis. RESULTS Three hundred and seven patients had at least one US examination and concomitant clinical information on disease activity. More than a third of patients in both DAS28 and ACR/EULAR remission showed significant gray scale synovitis (P=0.01 and 0.0002, respectively) and PwD activity (P=0.005 and 0.0005, respectively) when compared to controls. The capacity of US to discriminate between the two clinical remission groups and patients with active disease was only moderate. CONCLUSION This observational study confirms that many patients considered to be in clinical remission according the DAS and the ACR/EULAR definitions still have residual synovitis on US. The prognostic significance of US synovitis and the exact place of US in patients reaching clinical remission need to be further evaluated.

Ultrasound evaluation of synovitis in RA: correlation with clinical disease activity and sensitivity to change in an observational cohort study.

OBJECTIVE To evaluate the correlation between clinical measures of disease activity and a ultrasound (US) scoring system for synovitis applied by many different ultrasonographers in a daily routine care setting within the Swiss registry for RA (SCQM) and further to determine the sensitivity to change of this US Score. METHODS One hundred and eight Swiss rheumatologists were trained in performing the Swiss Sonography in Arthritis and Rheumatism (SONAR) score. US B-mode and Power Doppler (PwD) scores were correlated with DAS28 and compared between the clinical categories in a cross-sectional cohort of patients. In patients with a second US (longitudinal cohort), we investigated if change in US score correlated with change in DAS and evaluated the responsiveness of both methods. RESULTS In the cross-sectional cohort with 536 patients, correlation between the B-mode score and DAS28 was significant but modest (Pearson coefficient r = 0.41, P < 0.0001). The same was true for the PwD score (r = 0.41, P < 0.0001). In the longitudinal cohort with 183 patients we also found a significant correlation between change in B-mode and in PwD score with change in DAS28 (r = 0.54, P < 0.0001 and r = 0.46, P < 0.0001, respectively). Both methods of evaluation (DAS and US) showed similar responsiveness according to standardized response mean (SRM). CONCLUSIONS The SONAR Score is practicable and was applied by many rheumatologists in daily routine care after initial training. It demonstrates significant correlations with the degree of as well as change in disease activity as measured by DAS. On the level of the individual, the US score shows many discrepancies and overlapping results exist.

Fort Richardson Ordnance Detonations and the Harbor Porpoise: A Case Study in Marine Mammal Bioacoustics

Hearing is extremely important for cetaceans because it is their “principal sense” (Weilgart, 2007) thus the harbor porpoise and other marine animals are highly dependent on sound for survival. This is why we should care about the impact of noise on animals like the harbor porpoise. Since sound travels so well in water, an explosion, sonar, boat noise, etc. can affect a very large area and thus many different species of marine mammals. Although military actions such as low frequency sonar have made recent news, noise has been affecting cetaceans, especially beaked whales, since at least 1991 (Weilgart, 2007). This study is an investigation of the possible impacts of artillery detonated on land on harbor porpoise hearing and covers some of the history of Fort Richardson, the legal and historical aspects and history of this type of concern, the science and physics of sound, marine mammal hearing and general biology of the harbor porpoise. Data were collected at the Fort Richardson Army base during June of 2007 by researchers from the University of Connecticut and the University of Rhode Island and will be used to determine the possible impacts that these detonations could have on the harbor porpoise.

(Table 1) Summary of sampling points described and main petrographic, morphological and geochemical characteristics

Targeted sampling on the Dolgovskoy Mound (northern Shatsky Ridge) revealed the presence of spectacular laterally extensive and differently shaped authigenic carbonates. The sampling stations were selected based on sidescan sonar and profiler images that show patchy backscatter and irregular and discontinuous reflections in the near subsurface. The interpretation of acoustic data from the top part of the mound supports the seafloor observations and the sampling that revealed the presence of a complex subsurface plumbing system characterized by carbonates and gas. The crusts sampled consist of carbonate cemented layered hemipelagic sedimentary Unit 1 associated with several centimetres thick microbial mats. Three different carbonate morphologies were observed: (a) tabular slabs, (b) subsurface cavernous carbonates consisting of void chambers up to 20 cm**3 in size and (c) chimney and tubular conduits vertically oriented or forming a subhorizontal network in the subsurface. The methanogenic origin of the carbonates is established based on visual observations of fluids seepage structures, 13C depletion of the carbonates (d13C varying between -36.7 per mil and -27.4 per mil), and by thin carbonate layers present within the thick microbial mats. Laboratory experiments with a Hele-Shaw cell were conducted in order to simulate the gas seepage through contrasting grain size media present on the seafloor. Combined petrography, visual observations and sandbox simulations allowed a characterization of the dynamics and the structures of the plumbing system in the near subsurface. Based on sample observations and the experiments, three observed morphologies of authigenic carbonates are interpreted, respectively, as (a) Darcian porous flow through the finely laminated clayey/coccolith-rich layers, (b) gas accumulation chambers at sites where significant fluid escape was impeded by thicker clayey layers forming the laminated Unit1 and (c) focussed vertical fluid venting and subhorizontal migration of overpressured fluids released from (b). The Hele-Shaw cell experiments represent a promising tool for investigating shallow fluid flow pathways in marine systems.

Beatriz Guido, notas oscuras para narrar la modernidad

Tras el golpe de Estado de 1955, los proyectos que se asentaron en el poder apelaron a plataformas en las que incorporaban elementos de modernización, con las que, por otro lado, buscaban tomar distancia de la década peronista, que asociaban, entre otras cosas, al estancamiento cultural. Beatriz Guido, cuyo nombre comenzó a sonar en los ámbitos literarios a fines de 1954 con la publicación de La casa del ángel, era parte de los jóvenes escritores críticos del gobierno de Perón que emergieron alrededor de la Libertadora y cuya escritura se sumó al agitado circuito cultural posterior al golpe. Sin embargo, sus novelas y cuentos no evidencian una clara intención de modernización del lenguaje y muestran pocas innovaciones en el aspecto narrativo. En cambio puede apreciarse en esos relatos una indagación insistente en la subjetividad de sus personajes que se vuelca en la ruptura de la conciencia narrativa; subjetividad que aparece fragmentada y oscilante en un marco de las transformaciones políticas y sociales. Este recurso (que podría remitir a algún aspecto modernista), junto al pesimismo social, revelan en clave gótica, en cambio, una estética que contradice aquellos pilares discursivos con que los militares y el frondicismo apuntalaron su poder. El presente trabajo busca así pensar la producción cultural vinculando los elementos literarios con la dimensión que alcanzaban en el debate en un momento en que las esferas cultural, social y política estaban particularmente imbricadas

Maps of coastal and marine geomorphology between Albenga and Savona (NW Mediterranean Sea, Italy)

In this paper, we present a map describing the main geomorphological features of the coastal and marine area between the towns of Albenga and Savona (Ligurian Sea, NW Mediterranean) corresponding to a coastal stretch of ~40 km. To produce this map, we collated data from the literature, orthophotos, perspective photos, multibeam and side scan sonar data, and undertook direct surveys to ground truth data obtained using indirect techniques. We divided the information into nine thematic layers, including bathymetry, natural coastal types, geomorphological elements, seafloor coverage (both geological and biological), coastal and nearshore dynamics, human influence on coastal and marine environments, coastal occupation and protected areas.

Beatriz Guido, notas oscuras para narrar la modernidad

Tras el golpe de Estado de 1955, los proyectos que se asentaron en el poder apelaron a plataformas en las que incorporaban elementos de modernización, con las que, por otro lado, buscaban tomar distancia de la década peronista, que asociaban, entre otras cosas, al estancamiento cultural. Beatriz Guido, cuyo nombre comenzó a sonar en los ámbitos literarios a fines de 1954 con la publicación de La casa del ángel, era parte de los jóvenes escritores críticos del gobierno de Perón que emergieron alrededor de la Libertadora y cuya escritura se sumó al agitado circuito cultural posterior al golpe. Sin embargo, sus novelas y cuentos no evidencian una clara intención de modernización del lenguaje y muestran pocas innovaciones en el aspecto narrativo. En cambio puede apreciarse en esos relatos una indagación insistente en la subjetividad de sus personajes que se vuelca en la ruptura de la conciencia narrativa; subjetividad que aparece fragmentada y oscilante en un marco de las transformaciones políticas y sociales. Este recurso (que podría remitir a algún aspecto modernista), junto al pesimismo social, revelan en clave gótica, en cambio, una estética que contradice aquellos pilares discursivos con que los militares y el frondicismo apuntalaron su poder. El presente trabajo busca así pensar la producción cultural vinculando los elementos literarios con la dimensión que alcanzaban en el debate en un momento en que las esferas cultural, social y política estaban particularmente imbricadas

Beatriz Guido, notas oscuras para narrar la modernidad

Tras el golpe de Estado de 1955, los proyectos que se asentaron en el poder apelaron a plataformas en las que incorporaban elementos de modernización, con las que, por otro lado, buscaban tomar distancia de la década peronista, que asociaban, entre otras cosas, al estancamiento cultural. Beatriz Guido, cuyo nombre comenzó a sonar en los ámbitos literarios a fines de 1954 con la publicación de La casa del ángel, era parte de los jóvenes escritores críticos del gobierno de Perón que emergieron alrededor de la Libertadora y cuya escritura se sumó al agitado circuito cultural posterior al golpe. Sin embargo, sus novelas y cuentos no evidencian una clara intención de modernización del lenguaje y muestran pocas innovaciones en el aspecto narrativo. En cambio puede apreciarse en esos relatos una indagación insistente en la subjetividad de sus personajes que se vuelca en la ruptura de la conciencia narrativa; subjetividad que aparece fragmentada y oscilante en un marco de las transformaciones políticas y sociales. Este recurso (que podría remitir a algún aspecto modernista), junto al pesimismo social, revelan en clave gótica, en cambio, una estética que contradice aquellos pilares discursivos con que los militares y el frondicismo apuntalaron su poder. El presente trabajo busca así pensar la producción cultural vinculando los elementos literarios con la dimensión que alcanzaban en el debate en un momento en que las esferas cultural, social y política estaban particularmente imbricadas

(Table 1) Sea level during storm surges at various sites along the german Baltic Sea coast

A seawall was constructed in 1897 along the steep coast of Streckelsberg, Usedom Island to stop the cliff retreat. It was destroyed several times by storm induced sea floods, reconstructed and gradually extended to a length of 450 m. After the severe storm event of 1/2.3.1949, no more repair work was implemented. The ruins were no longer capable of preventing further erosion of the Streckelsberg cliff. A new protective structure became a necessity against ongoing erosion, and to check the lowering of the abrasion platform. The construction of three breakwaters began in 1995. A severe storm occurred on 3/4.11.1995 before their completion. Coastal bottom sediment mapping using a sidescan-sonar carried out two days later showed that a channel system down to a depth of 1.5 m was cut into the sand layer covering the sea floor on both sides of the Koserow Bank. The bottom of these channels was paved with gravel and boulders. This layer was encountered in the whole surveyed area below a mobile sand layer. Discharged bodies of fine sand half a meter high and erosional cavities several m2 in diameter around boulders led to the conclusion that an intensive sediment movement down to a depth of 11 m had taken place during the storm. A storm related direction of sediment discharge could not be identified. The existing section of the breakwaters withstood the severe storm.

Digital terrain model (DTM) of the central Fram Strait

Based on data from R/V Polarstern multibeam sonar surveys between 1984 and 1997 a high resolution bathymetry has been generated for the central Fram Strait. The area ensonified covers approx. 36,500 sqkm between 78°N-80°N and 0°E-7.5°E. Basic outcome of the investigation is a Digital Terrain Model (DTM) with 100 m grid spacing which was utilized for contouring and generation of a new series of bathymetric charts (AWI BCFS).