939 research outputs found
PHYCOBILISOMES AND ISOLATED PHYCOBILIPROTEINS. EFFECT OF GLUTARDIALDEHYDE AND BENZOQUINONE ON FLUORESCENCE
The fluorescence of the biliproteins C-phycocyanin from Spirulina platensis, B-phycoerythrin
from Porphyridium cruentum and of isolated whole P. cruentum phycobilisomes is quenched in the
presence of glutardialdehyde (GA) or benzoquinone (BQ). The kinetics of fluorescence decrease thus
induced is biphasic. If GA is used as a quencher, the fluorescence can be recovered at 77 K. Contrary to
the GA-effect, only a minor recovery takes place with BQ at 77K, thus demonstrating a different
mechanism of action of GA and BQ on biliprotein
The Accretion Rates and Spectral Energy Distributions of BL Lacertae Objects
We investigate the relationship between accretion rates and the spectral
energy distributions (SEDs) of BL Lac objects, using a sample of objects for
which published information on the host galaxies, emission-line luminosities,
and peak frequencies and luminosities of their SEDs are available. The sample
is composed of 43 BL Lac objects which have a relatively continuous
distribution of peak frequencies. Under the assumption that the observed
emission lines are photoionized by the central accretion disk, we use the line
luminosities to estimate the accretion luminosities and hence accretion rates.
We find that low frequency-peaked BL Lac objects (LBLs) span a wide range of
accretion rates, whereas high frequency-peaked BL Lac objects (HBLs) cover a
more restricted range of lower values. There appears to be a continuous
distribution of accretion rates between the two subclasses of BL Lac objects.
We find that the peak frequency of the SED, \pknu, correlates with the
accretion rate, approximately with the form \pknu\propto \Lambda^{-3} in HBLs
and \pknu \propto \Lambda^{-0.25} in LBLs, where . The peak luminosity of the SED is also correlated with .
These results suggest that the accretion rate influences the shape of the SED
in BL Lac objects. They also support models which couple the jet and the
accretion disk. We present a physical scenario to account for the empirical
trends.Comment: 6 pages in emulateapj.sty, 3 figures 1 table. The Astrophysical
Journal (in press
The alpha-effect and current helicity for fast sheared rotators
We explore the alpha-effect and the small-scale current helicity, for the
case of weakly compressible magnetically driven turbulence that is subjected to
the differential rotation. No restriction is applied to the amplitude of
angular velocity, i.e., the derivations presented are valid for an arbitrary
Coriolis number, though the differential rotation itself is assumed to be weak.
The expressions obtained are used to explore the possible distributions of
alpha-effect and current helicity in convection zones (CZ) of the solar-type
stars. The implications of the obtained results to the mean-field dynamo models
are discussed.Comment: 20 pages, 6 figure
Intensivmedizinische Behandlung von Erwachsenen mit angeborenen Herzfehlern
Zusammenfassung: Dank Verbesserungen in der Herzchirurgie und der perioperativen Betreuung steigt die Anzahl der Erwachsenen mit einem angeborenen Herzfehler stetig. Die perioperative und intensivmedizinische Betreuung dieser Patienten stellt aufgrund der vielen verschiedenen Pathologien und chirurgischen MĂśglichkeiten sowie der komplexen Pathophysiologie eine Herausforderung dar. Viele Patienten entwickeln mit der Zeit Organdysfunktionen und viele von ihnen benĂśtigen Folgeoperationen am Herzen sowie nichtkardiale Eingriffe im Erwachsenalter. Aufgrund der Komplexität sind diese Patienten in spezialisierten tertiären Krankenhäusern zu behandeln, die Ăźber ein disziplinenĂźbergreifendes Fachwissen verfĂźgen. Da dies in Notfällen nicht immer mĂśglich sein wird, sind grundlegende Kenntnisse dieser Patientengruppe fĂźr in der Akutversorgung Tätige wichtig. In dieser Ăbersicht werden allgemeine Aspekte, wie pulmonale Hypertonie, Eisenmenger-Syndrom, Zyanose, Schwangerschaft und perioperative Betreuung, behandelt. Ein besonderes Augenmerk gilt dabei der intensivmedizinischen Versorgung von kritisch kranken Patienten mit angeborenen Herzfehler
Magnetic field generation in fully convective rotating spheres
Magnetohydrodynamic simulations of fully convective, rotating spheres with
volume heating near the center and cooling at the surface are presented. The
dynamo-generated magnetic field saturates at equipartition field strength near
the surface. In the interior, the field is dominated by small-scale structures,
but outside the sphere by the global scale. Azimuthal averages of the field
reveal a large-scale field of smaller amplitude also inside the star. The
internal angular velocity shows some tendency to be constant along cylinders
and is ``anti-solar'' (fastest at the poles and slowest at the equator).Comment: 12 pages, 11 figures, 2 tables, to appear in the 10 Feb issue of Ap
Hemophagocytic syndrome caused by primary herpes simplex virus 1 infection: report of a first case
Introduction: Hemophagocytic syndrome represents a severe hyperinflammatory condition by activated macrophages. Leading viral triggering agents are Epstein-Barr virus (EBV), cytomegalovirus (CMV), and adenovirus. Materials and methods: We present a patient with Wegener's granulomatosis on azathioprine and prednisone medication, who developed a life-threatening hemophagocytic syndrome. Positive plasma polymerase chain reaction (PCR) with negative serology revealed a primary, disseminated infection with herpes simplex virus-1 as the triggering pathogen. After treatment with acyclovir, high-dose steroids, immunoglobulins, and etoposide, the patient recovered. Conclusion: Early diagnosis of potentially underlying infections of hemophagocytic syndrome influences the therapeutic approach. It is important to consider a variety of infectious agents, particularly in immunosuppressed individuals. The reported case emphasizes the importance of screening for herpes simplex virus
Angular dependence of domain wall resistivity in SrRuO films
is a 4d itinerant ferromagnet (T 150 K) with
stripe domain structure. Using high-quality thin films of SrRuO we study
the resistivity induced by its very narrow ( nm) Bloch domain walls,
(DWR), at temperatures between 2 K and T as a function of the
angle, , between the electric current and the ferromagnetic domains
walls. We find that which provides the first experimental
indication that the angular dependence of spin accumulation contribution to DWR
is . We expect magnetic multilayers to exhibit a similar
behavior.Comment: 5 pages, 5 figure
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