195 research outputs found
Acoustic penetration and impact detector for micrometeoroid and space debris application
The Two-Stage Acoustic Penetration and Impact Detector is a simple device for measuring the impact event time, the projectile velocity, the flight path direction and the momentum. The results of laboratory tests have shown that this detector can be used in a wide range of projectile size and velocity. According to measurement purposes the size of the detection area, the distance between the front foil and the target plate and the number of microphones as well as the evaluation procedure can easily be adjusted. The target plate area can also be replaced by another foil detector, if two penetration stages are preferred. This active detector is suitable for a variety of applications in meteoroid and space debris exploration. It can also be supplied with capture cell properties for chemical analysis of inside-deposits. Therefore, this measurement principal has been taken into consideration as a possible flight experiment for instance for a later Longer Duration Exposure Facility (LDEF) flight or future space station activities
Plasma adiponectin levels and sonographic phenotypes of subclinical carotid artery atherosclerosis : Data from the SAPHIR study
Copyright: Copyright 2008 Elsevier B.V., All rights reserved.Background and Purpose - Adipose tissue produces and secretes a number of bioactive molecules, conceptualized as adipocytokines. Adiponectin has been identified as one of the adipocytokines, and hypoadiponectinemia was demonstrated in patients with obesity, diabetes mellitus, and coronary artery disease. Whether decreased adiponectin levels are cause or consequence is an important issue in the discussion on the association between adiponectin and atherosclerosis. In the present study, we investigated the association of plasma adiponectin levels with sonographic phenotypes of subclinical atherosclerosis, which may represent different stages of disease as well as common and distinct determinants. Methods - A total of 1515 middle-aged healthy white subjects (940 males and 575 females) were included. Common carotid artery intima-media thickness (CIMT) and presence of atherosclerotic plaques were assessed by B-mode ultrasound. Results - After adjustment for established risk factors, per 1 μg/mL decrease in adiponectin CIMT increased on the average by 3.48 μ in males (95% CI, 1.23 to 5.73 μm) and by 2.39 μ in females (95% CI, 0.50 to 4.27 μm). After dichotomizing adiponectin levels at the median and adjustment for established risk factors, the mean difference of CIMT between subjects with low and high adiponectin levels was 20.42 μm in men (95% CI, 6.80 to 34.04; P=0.003) and 20.75 μ in women (95% CI, 1.08 to 40.42; P=0.039). No significant relationship was found between adiponectin levels and presence of atherosclerotic plaques. Conclusion - Our results demonstrate an independent negative association of adiponectin levels and CIMT, whereas no relationship with presence of atherosclerotic plaques was found, thus suggesting hypoadiponectinemia as a risk factor in the development of early atherosclerosis.publishersversionPeer reviewe
BREM-SAT - A Small Scientific Satellite
BREM-SAT is a small scientific satellite being financed by the BMFT (German Ministry of Research and Technology). It will be launched from the Space Shuttle during the German D-2 mission (September 1992) into a 300 km orbit with 28.5° inclination. Although the volume is limited, due to the CAP (Complex Autonomous Payload) programme requirements, the satellite payload includes six different scientific experiments. Futhermore, within this mission a new technology will be demonstrated
Devonian to Permian intrusions in the Zentralgneis Supersuite of the eastern Tauern Window constrained by U-Pb zircon geochronology and geochemistry
In the course of comprehensive geological mapping, the Geosphere Austria (formerly Geologische Bundesanstalt – Geological Survey of Austria) initiated a systematic geochemical and geochronological characterization of the metamorphic granitoids forming the Zentralgneis Supersuite in the eastern Tauern Window. Three dozens of samples from already defined units (Sonnblick, Siglitz, Romate, Göss, and Hochalm orthogneiss) as well as newly defined units (Säuleck, Kampleck, and Grübelwand orthogneisses) were sampled in four different nappes of the Venediger Nappe-System (Sonnblick, Romate, Hochalm, and Göss nappe).
Major and trace element geochemical analyses indicate three groups. Most of the Sonnblick orthogneiss samples, the Siglitz orthogneiss and other non-leucocratic orthogneisses derive from high-K, calc-alkaline granite with a peraluminous and magnesian composition. The analyzed samples classify as I-type (subordinately S-type) granites formed in volcanic arcs and show no negative Eu-anomaly. The Kampleck, Säuleck, and Grübelwand orthogneiss as well as leucocratic orthogneisses derive from high-Si, calc-alkaline granite, aplite and pegmatite, with a peraluminous ferroan composition. This group classifies as S-type granites formed in a within-plate setting and samples show a clear negative Eu-anomaly as well as comparably low Ba and Sr concentrations. The Romate orthogneiss and one analyzed Sonnblick orthogneiss sample derive from shoshonitic, quartz-monzonite to syenite with metaluminous and magnesian composition. This group classifies as syn-collisional A-Type granites and shows no negative Eu-anomaly with comparably high Eu, U and Th concentrations.
The three distinguished groups are found in different nappes of the Venediger Nappe System; however, note that single orthogneiss units can host elements of different characteristics.
U-Pb zircon geochronology further constrains some of the orthogneiss units. A sample of coarse-grained Sonnblick orthogneiss with an augen microstructure yields a Late Devonian age. An atypical fine-grained Sonnblick orthogneiss with small K-feldspar yields a late Carboniferous age and a Siglitz orthogneiss sample yields an early Carboniferous age. Samples from Kampleck, Säuleck and Grübelwand yield middle Permian ages.
Our findings illustrate the complex and long lived intrusion story over 100 Myrs hidden in what is called the Zentralgneis Supersuite. The dominant group corresponding to I-type calc-alkaline plutonism contemporaneous to the Variscan Orogeny took more than 30 Myrs to form. At least in the Sonnblick orthogneiss, this group hosts younger intrusions that remain undefined and unmapped. Later Permian S-type intrusions are for the moment only attested in the Hochalm Nappe. However, based on lithological characteristics these can also be expected in other nappes (e.g. Sonnblick and Göss nappe). Finally, geochronological characterization of the Romate orthogneiss underpins any interpretation of its exotic chemistry. These results stress the importance of combined geochemical and geochronological analyses together with geological mapping for a more comprehensive understanding of the complex geological situation in the eastern Tauern Window
The Serifos Metamorphic Core Complex (Greece) — kinematic investigations of the southern detachment mylonites
The island of Serifos is situated about
100km SSE of Athens in the Aegean
Sea and belongs to the Attic-Cycladic
massif. The geology of Serifos is largely
characterized by a shallow hornblendebiotite
granodiorite pluton that intruded
in the late Miocene into a previously
deformed (under blueschist conditions)
sequence mainly consisting of
ortho- and paragneisses, calc-silicate
marbles, amphibolites and schists. The
pluton has a dome-shaped body occupying
the central and southern parts of
the island (Salemink 1985). The Serifos
MCC is the very western continuation of a zone of syn- to post tectonic intrusions
younging from the East (Naxos,
Paros ?12Ma) to the West (Serifos 9–
8Ma). Whereas the older intrusions in
the East show a top to the North geometry,
the Serifos MCC has developed
a South-directed low-angle detachment
fault...conferenc
Response to letter by Pilz et al
Copyright: Copyright 2008 Elsevier B.V., All rights reserved.publishersversionPeer reviewe
Late stage evolution of the Serifos Metamorphic Core Complex (Cyclades, Greece)
The island of Serifos is located in
the Western Cyclades within the Attic-
Cycladic metamorphic belt. It represents
the westward continuation of an
arcuate belt of Metamorphic Core Complexes
with intrusions of late syn-post
tectonic intrusions younging from East
(e.g. Naxos main activity ca. 12Ma)
to West (e.g. Serifos with 9–8Ma). In
scientific discussions the dominance of
probably continuous extension since ca.
30Ma (e.g. Jolivet & Faccenna, 2000)
and the presence of Metamorphic Core
Complexes (Lister et al. 1984) is accepted.
The speculated roll-back of
the subducting plate possibly started
due to the slowing down of absolute
plate convergence rate between Africa
and Eurasia. This model is attractive,
because it would also explain the
shift from a compressional Andean-type
regime to an extensional Mariana-type
regime (Jolivet & Faccenna 2000). Contrary
to the kinematic directions reported
from the Central and Eastern
Cyclades, the movement of the hanging wall of the Serifos Metamorphic Core
Complex is south directed. The island’s
main part is occupied by an undeformed
granodiorite. Early granitic intrusions
intruded into low-grade M2-crystalline
rocks that have been overprinted to as
high as amphibolite facies conditions
due to contact metamorphism. Parts of
these rocks (gneisses and amphibolites)
as well as the early intrusions are deformed
to mylonites (Grasemann et al.
2004).conferenc
Kinematics and deformation structures in a crustal-scale shear zone on Kea (W. Cyclades, Greece)
It is generally agreed upon that the exhumation
of metamorphic rocks in the
Aegean is caused by post orogenic extension
in the late Oligocene to early
Miocene. This extension is in principle
largely accommodated by low-angle
crustal detachment faulting possibly resulting
in the formation of metamorphic
core complexes (MCC).
Here, we present data from recent structural
investigations on the island of Kea
in the W. Cyclades, Greece. Our work
focussed in the north of the island. Of
the ca. 270m total structural thickness
that was mapped, the entire section
of rocks are highly strained. Exhumation
during progressive deformation is
recorded by the transition from ductile
to brittle/ductile to brittle conditions.
The regional characteristics and types
of deformation structures vary depending
on the protolith and the intensity of
strain...conferenc
Extensional crustal-scale shear zones in the Western Cyclades (Kea, Greece)
Intense seismicity and intensely developed
active and ancient fault systems
are common to the Aegean Region. Extending/
thinning crust involves a complex
interplay of (1) Gulf of Corinth riftexpansion,
(2) west- and south-ward retreat
of the Hellenic Trench, (3) westward
impingement of the Anatolian
Platen, and/or (4) propagation of the
Anatolian Fault system into the Aegean.
New geological/structural investigations
on Kea (also known as Tzia), in
the Western Cyclades reveal a low angle
crustal-scale, detachment-type ductile
shear zone probably formed during
Miocene extension and thinning of the
continental crust...conferenc
Sequencing patterns of ventilatory indices in less trained adults
Submaximal ventilatory indices, i.e., point of optimal ventilatory efficiency (POE) and anaerobic threshold (AT), are valuable indicators to assess the metabolic and ventilatory response during cardiopulmonary exercise testing (CPET). The order in which the ventilatory indices occur (ventilatory indices sequencing pattern, VISP), may yield additional information for the interpretation of CPET results and for exercise intensity prescription. Therefore, we determined whether different VISP groups concerning POE and AT exist. Additionally, we analysed fat metabolism via the exercise intensity eliciting the highest fat oxidation rate (Fatmax) as a possible explanation for differences between VISP groups. 761 less trained adults (41–68 years) completed an incremental exercise test on a cycle ergometer until volitional exhaustion. The ventilatory indices were determined using automatic and visual detection methods, and Fatmax was determined using indirect calorimetry. Our study identified two VISP groups with a lower work rate at POE compared to AT in VISPPOE < AT but not in group VISPPOE = AT. Therefore, training prescription based on POE rather than AT would result in different exercise intensity recommendations in 66% of the study participants and consequently in unintended physiological adaptions. VISPPOE < AT participants were not different to VISPPOE = AT participants concerning VO2peak and Fatmax. However, participants exhibiting a difference in work rate (VISPPOE < AT) were characterized by a higher aerobic capacity at submaximal work rate compared to VISPPOE = AT. Thus, analysing VISP may help to gain new insights into the complex ventilatory and metabolic response to exercise. But a methodological framework still must be established
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