5,118 research outputs found
Ektopes Prostatagewebe in der Cervix uteri
Zusammenfassung: Ektopes Prostatagewebe ist ein selten beobachtetes Phänomen im unteren Genitaltrakt der Frau. Ätiologisch werden Entwicklungsanomalien, eine Metaplasie vorbestehender endozervikaler Drüsen und Reste embryonaler Genitalanlagen diskutiert. Wir berichten über ektopes Prostatagewebe in der Cervix uteri einer 82-jährigen Patientin. Dieses Gewebe fand sich als Zufallsbefund in einem Hysterektomiepräparat. Diese ungewöhnliche Läsion sollte besonders von atypischen glandulären Läsionen der Cervix uteri abgegrenzt werden. Immunhistochemische Zusatzuntersuchungen sichern die Diagnos
Diurnal and annual variations of meteor rates at the arctic circle
Meteors are an important source for (a) the metal atoms of the upper atmosphere metal layers and (b) for condensation nuclei, the existence of which are a prerequisite for the formation of noctilucent cloud particles in the polar mesopause region. For a better understanding of these phenomena, it would be helpful to know accurately the annual and diurnal variations of meteor rates. So far, these rates have been little studied at polar latitudes. Therefore we have used the 33 MHz meteor radar of the ALOMAR observatory at 69° N to measure the meteor rates at this location for two full annual cycles. This site, being within 3° of the Arctic circle, offers in addition an interesting capability: The axis of its antenna field points (almost) towards the North ecliptic pole once each day of the year. In this particular viewing direction, the radar monitors the meteoroid influx from (almost) the entire ecliptic Northern hemisphere. <P style='line-height: 20px;'> We report on the observed diurnal variations (averaged over one month) of meteor rates and their significant alterations throughout the year. The ratio of maximum over minimum meteor rates throughout one diurnal cycle is in January and February about 5, from April through December 2.3±0.3. If compared with similar measurements at mid-latitudes, our expectation, that the amplitude of the diurnal variation is to decrease towards the North pole, is not really borne out. <P style='line-height: 20px;'> Observations with the antenna axis pointing towards the North ecliptic pole showed that the rate of deposition of meteoric dust is substantially larger during the Arctic NLC season than the annual mean deposition rate. The daylight meteor showers of the Arietids, Zeta Perseids, and Beta Taurids supposedly contribute considerably to the June maximum of meteor rates. We note, though, that with the radar antenna pointing as described above, all three meteor radiants are close to the local horizon but all three radiants were detected
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The varieties of remembered experience: Moving memory beyond the bounded self
We review the contributions to this Special Issue that highlight the diverse ways in which memory takes place that go beyond the standard personal autobiographical memory and its reliance on internal imagery. We look at how contributors explore a highly individual memory of trauma and re-consider it as a complex, socially contested phenomenon. We next turn to a discussion of shared memory within dyads and then look at a contribution that examines bodily and gestural alignment during shared recollection among group members and/or families. From there, contributors raise considerations of collective memory in prisoner-of-war survivors and among football fans attending a World Cup event. The next contribution illustrates how collective forgetting creates social bonds in a similar manner to collective remembering. Finally, we show how the boundaries of memory are being stretched by digital technology through its influence on how we recall and share memories. Methodological innovations are also discussed
Focusing a deterministic single-ion beam
We focus down an ion beam consisting of single 40Ca+ ions to a spot size of a
few mum using an einzel-lens. Starting from a segmented linear Paul trap, we
have implemented a procedure which allows us to deterministically load a
predetermined number of ions by using the potential shaping capabilities of our
segmented ion trap. For single-ion loading, an efficiency of 96.7(7)% has been
achieved. These ions are then deterministically extracted out of the trap and
focused down to a 1sigma-spot radius of (4.6 \pm 1.3)mum at a distance of 257mm
from the trap center. Compared to former measurements without ion optics, the
einzel-lens is focusing down the single-ion beam by a factor of 12. Due to the
small beam divergence and narrow velocity distribution of our ion source,
chromatic and spherical aberration at the einzel-lens is vastly reduced,
presenting a promising starting point for focusing single ions on their way to
a substrate.Comment: 16 pages, 7 figure
Controlling the transport of an ion: Classical and quantum mechanical solutions
We investigate the performance of different control techniques for ion
transport in state-of-the-art segmented miniaturized ion traps. We employ
numerical optimization of classical trajectories and quantum wavepacket
propagation as well as analytical solutions derived from invariant based
inverse engineering and geometric optimal control. We find that accurate
shuttling can be performed with operation times below the trap oscillation
period. The maximum speed is limited by the maximum acceleration that can be
exerted on the ion. When using controls obtained from classical dynamics for
wavepacket propagation, wavepacket squeezing is the only quantum effect that
comes into play for a large range of trapping parameters. We show that this can
be corrected by a compensating force derived from invariant based inverse
engineering, without a significant increase in the operation time
Controlling fast transport of cold trapped ions
We realize fast transport of ions in a segmented micro-structured Paul trap.
The ion is shuttled over a distance of more than 10^4 times its groundstate
wavefunction size during only 5 motional cycles of the trap (280 micro meter in
3.6 micro seconds). Starting from a ground-state-cooled ion, we find an
optimized transport such that the energy increase is as low as 0.10 0.01
motional quanta. In addition, we demonstrate that quantum information stored in
a spin-motion entangled state is preserved throughout the transport. Shuttling
operations are concatenated, as a proof-of-principle for the shuttling-based
architecture to scalable ion trap quantum computing.Comment: 5 pages, 4 figure
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