782 research outputs found
Invasive Techniken in der Notfallmedizin: IV. Koniotomie im Notarztdienst
Zusammenfassung: Die Koniotomie im Notarztdienst ist eine sehr invasive Methode zur Atemwegssicherung. Sie ist aber unabdingbar, wenn andere weniger invasive Verfahren der Atemwegssicherung misslingen oder sich situationsabhängig als nicht zweckmäßig erweisen. Für die Durchführung wurden verschiedene Verfahren beschrieben, die in anatomisch-chirurgische Präpariertechniken und Punktionsverfahren unterteilt werden können. Das im jeweiligen Notarztsystem bevorzugte Verfahren orientiert sich meist an abteilungsüblichen Standards, die vom klinischen Vorgehen abgeleitet werden. Ausbildungs- und Trainingsmöglichkeiten für die einzelnen Verfahren bestehen in der Intensivmedizin, am Leichenpräparat und am Phantom. In dieser Arbeit werden verschiedene Methoden der Koniotomie besprochen sowie eine anatomische Präpariertechnik und 2Punktionsverfahren im Detail dargestell
Spin dephasing and photoinduced spin diffusion in high-mobility 110-grown GaAs-AlGaAs two-dimensional electron systems
We have studied spin dephasing and spin diffusion in a high-mobility
two-dimensional electron system, embedded in a GaAs/AlGaAs quantum well grown
in the [110] direction, by a two-beam Hanle experiment. For very low excitation
density, we observe spin lifetimes of more than 16 ns, which rapidly decrease
as the pump intensity is increased. Two mechanisms contribute to this decrease:
the optical excitation produces holes, which lead to a decay of electron spin
via the Bir-Aranov-Pikus mechanism and recombination with spin-polarized
electrons. By scanning the distance between the pump and probe beams, we
observe the diffusion of spin-polarized electrons over more than 20 microns.
For high pump intensity, the spin polarization in a distance of several microns
from the pump beam is larger than at the pump spot, due to the reduced
influence of photogenerated holes.Comment: 4 pages, 3 figure
Die Bundestagswahl 2002 : Erfolg in letzter Minute?
Bei der Bundestagswahl am 22. September 2002 erlebten die Parteien und Wähler den knappsten Wahlausgang seit der deutschen Wiedervereinigung. Erst nach einem wahren Hochrechnungs-Krimi stand um Mitternacht fest, dass Bundeskanzler Gerhard Schröder (SPD) und die Grünen die Wahl mit einer hauchdünnen Mehrheit gewonnen hatten. Bereits im Vorfeld der Bundestagswahl hatten sich beide Parteien dafür ausgesprochen,im Falle eines Wahlsiegs das rot-grüne Regierungsbündnis fortzusetzen
Vibrational States of the Hydrogen Isotopes on Pd(111)
The ground and excited vibrational states for the three hydrogen isotopes on
the Pd(111) surface have been calculated. Notable features of these states are
the high degree of anharmonicity, which is most prominently seen in the weak
isotopic dependence of the parallel vibrational transition, and the narrow
bandwidths of these states, which imply that atomic hydrogen is localized on a
particular surface site on time scales of 100 picoseconds or more. Experiments
to resolve ambiguities concerning the present system are suggested.Comment: Surface Science Letters, 302, L305 (1994
Vertrauen in politische Institutionen und politische Unterstützung
'Eine Voraussetzung für den Bestand repräsentativer Demokratien ist, dass die Bürger den politischen Institutionen ein gewisses Maß an Vertrauen entgegenbringen. Nach Easton (1965) ist das Konzept des politischen Vertrauens in dem Konzept der politischen Unterstützung zu verorten. 30 Jahre später kommt mit Putnam (1993) ein zweiter theoretischer Strang auf, der politisches Vertrauen als zentralen Bestandteil von Sozialkapital betrachtet. Das Ziel des Beitrags besteht darin, zu klären, welche Rolle das Institutionenvertrauen im Zusammenhang mit dem Unterstützungskonzept Eastons einerseits sowie dem Sozialkapitalansatz Putnams andererseits spielt. Die Analysen, die für die Länder Deutschland, Schweiz, Norwegen, Schweden, Spanien und die USA durchgeführt werden, basieren auf Daten der dritten Welle des World Values Surveys (1995-97). Als Untersuchungsergebnis lässt sich festhalten, dass eine generalisierte Dimension des Institutionenvertrauens in der Bevölkerung besteht, die die Verortung in Eastons Konzept politischer Unterstützung rechtfertigt. Bei einer Differenzierung des Vertrauens der Bürger zu Institutionen des Rechtsstaats (Polizei, Justiz) und des Parteienstaats (Parlament, Parteien, Regierung) zeigt sich jedoch, dass Putnams Sozialkapitalkonzept ebenso einen relevanten Erklärungsbeitrag leistet.' (Autorenreferat)'A certain level of trust in political institutions has been assumed to be a prerequisite for the stability of representative democracies. Easton (1965) analysed political trust on the basis of the concept of political support. Thirty years later Putnam (1993) started a discussion which regards political confidence as an essential element of social capital. This article investigates the confidence in institutions within the framework of the concept of political support on the one hand and within the concept of social capital on the other. Analyses for Germany, Switzerland, Norway, Sweden, Spain, and the USA were conducted with data from the third wave of the World Values Survey (1995-1997). We found a generalized dimension of trust in institutions which vindicates Easton's concept of political support. If however a distinction is made between trust in institutions of the constitutional state (police, justice) and institutions of the party state (parliament, parties, government), then Putnam's concept of social capital also emerges as a relevant determinant.' (author's abstract
The rearing environment persistently modulates mouse phenotypes from the molecular to the behavioural level.
The phenotype of an organism results from its genotype and the influence of the environment throughout development. Even when using animals of the same genotype, independent studies may test animals of different phenotypes, resulting in poor replicability due to genotype-by-environment interactions. Thus, genetically defined strains of mice may respond differently to experimental treatments depending on their rearing environment. However, the extent of such phenotypic plasticity and its implications for the replicability of research findings have remained unknown. Here, we examined the extent to which common environmental differences between animal facilities modulate the phenotype of genetically homogeneous (inbred) mice. We conducted a comprehensive multicentre study, whereby inbred C57BL/6J mice from a single breeding cohort were allocated to and reared in 5 different animal facilities throughout early life and adolescence, before being transported to a single test laboratory. We found persistent effects of the rearing facility on the composition and heterogeneity of the gut microbial community. These effects were paralleled by persistent differences in body weight and in the behavioural phenotype of the mice. Furthermore, we show that environmental variation among animal facilities is strong enough to influence epigenetic patterns in neurons at the level of chromatin organisation. We detected changes in chromatin organisation in the regulatory regions of genes involved in nucleosome assembly, neuronal differentiation, synaptic plasticity, and regulation of behaviour. Our findings demonstrate that common environmental differences between animal facilities may produce facility-specific phenotypes, from the molecular to the behavioural level. Furthermore, they highlight an important limitation of inferences from single-laboratory studies and thus argue that study designs should take environmental background into account to increase the robustness and replicability of findings
Ant Mimicry by an Aphid Parasitoid, Lysiphlebus fabarum
In Iran, Lysiphlebus fabarum (Marshall) (Hymenoptera: Braconidae: Aphidiinae) is a uniparental parasitoid of the black bean aphid, Aphis fabae Scopoli (Hemiptera: Aphididae), that possesses various highly evolved adaptations for foraging within ant-tended aphid colonies. Direct observations and video recordings were used to analyze the behavior of individual females foraging for A. fabae on bean leaf disks in open arenas in the laboratory. Females exploited aphids as hosts and as a source of food, allocating within-patch time as follows: resting - 10.4%, grooming - 8.2%, searching - 11.5%, antennation (host recognition) - 7.5%, antennation (honeydew solicitation mimicking ants) - 31.9%, abdominal bending (attack preparation) 19.7%, probing with the ovipositor (attack) - 10.8%. The mean handling time for each aphid encountered was 2.0 ± 0.5 min. Females encountered an average of 47.4 ± 6.4 aphids per hour, but laid only 1.2 eggs per hour. The ovipositor insertion time for parasitism ranged from 2 sec to longer than a minute, but most insertions did not result in an egg being laid. A. fabae defensive behaviors included kicking, raising and swiveling the body, and attempts to smear the attacker with cornicle secretions, sometimes with lethal results. Food deprivation for 4–6 h prior to testing increased the frequency of ant mimcry by L. fabarum. Females also used ant-like antennation to reduce A. fabae defensive behavior, e.g. the frequency of kicking. L. fabarum attacks primed A. fabae to be more responsive to subsequent honeydew solicitation, such that experienced females improved their feeding success by alternating between the roles of parasitoid and ant mimic. These results reveal the possibility for mutualisms to evolve between L. fabarum and the ant species that tend A. fabae, since L. fabarum receive ant protection for their progeny and may benefit the ants by improving A. fabae responsiveness to honeydew solicitation
Multi-trait mimicry of ants by a parasitoid wasp
Many animals avoid attack from predators through toxicity or the emission of repellent chemicals. Defensive mimicry has evolved in many species to deceive shared predators, for instance through colouration and other morphological adaptations, but mimicry hardly ever seems to involve multi-trait similarities. Here we report on a wingless parasitoid wasp that exhibits a full spectrum of traits mimicing ants and affording protection against ground-dwelling predators (wolf spiders). In body size, morphology and movement Gelis agilis (Ichneumonidae) is highly similar to the black garden ant (Lasius niger) that shares the same habitat. When threatened, G. agilis also emits a volatile chemical that is similar to an ant-produced chemical that repels spiders. In bioassays with L. niger, G. agilis, G. areator, Cotesia glomerata and Drosophila melanogaster, ants and G. agilis were virtually immune to spider attack, in contrast the other species were not. Volatile characterisation with gas chromatography-mass spectrometry identified G. agilis emissions as 6-methyl-5-hepten-2-one, a known insect defence semiochemical that acts as an alarm pheromone in ants. We argue that multi-trait mimicry, as observed in G. agilis, might be much more common among animals than currently realized
Multiplicity dependence of jet-like two-particle correlations in p-Pb collisions at = 5.02 TeV
Two-particle angular correlations between unidentified charged trigger and
associated particles are measured by the ALICE detector in p-Pb collisions at a
nucleon-nucleon centre-of-mass energy of 5.02 TeV. The transverse-momentum
range 0.7 5.0 GeV/ is examined,
to include correlations induced by jets originating from low
momen\-tum-transfer scatterings (minijets). The correlations expressed as
associated yield per trigger particle are obtained in the pseudorapidity range
. The near-side long-range pseudorapidity correlations observed in
high-multiplicity p-Pb collisions are subtracted from both near-side
short-range and away-side correlations in order to remove the non-jet-like
components. The yields in the jet-like peaks are found to be invariant with
event multiplicity with the exception of events with low multiplicity. This
invariance is consistent with the particles being produced via the incoherent
fragmentation of multiple parton--parton scatterings, while the yield related
to the previously observed ridge structures is not jet-related. The number of
uncorrelated sources of particle production is found to increase linearly with
multiplicity, suggesting no saturation of the number of multi-parton
interactions even in the highest multiplicity p-Pb collisions. Further, the
number scales in the intermediate multiplicity region with the number of binary
nucleon-nucleon collisions estimated with a Glauber Monte-Carlo simulation.Comment: 23 pages, 6 captioned figures, 1 table, authors from page 17,
published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/161
Multi-particle azimuthal correlations in p-Pb and Pb-Pb collisions at the CERN Large Hadron Collider
Measurements of multi-particle azimuthal correlations (cumulants) for charged
particles in p-Pb and Pb-Pb collisions are presented. They help address the
question of whether there is evidence for global, flow-like, azimuthal
correlations in the p-Pb system. Comparisons are made to measurements from the
larger Pb-Pb system, where such evidence is established. In particular, the
second harmonic two-particle cumulants are found to decrease with multiplicity,
characteristic of a dominance of few-particle correlations in p-Pb collisions.
However, when a gap is placed to suppress such correlations,
the two-particle cumulants begin to rise at high-multiplicity, indicating the
presence of global azimuthal correlations. The Pb-Pb values are higher than the
p-Pb values at similar multiplicities. In both systems, the second harmonic
four-particle cumulants exhibit a transition from positive to negative values
when the multiplicity increases. The negative values allow for a measurement of
to be made, which is found to be higher in Pb-Pb collisions at
similar multiplicities. The second harmonic six-particle cumulants are also
found to be higher in Pb-Pb collisions. In Pb-Pb collisions, we generally find
which is indicative of a Bessel-Gaussian
function for the distribution. For very high-multiplicity Pb-Pb
collisions, we observe that the four- and six-particle cumulants become
consistent with 0. Finally, third harmonic two-particle cumulants in p-Pb and
Pb-Pb are measured. These are found to be similar for overlapping
multiplicities, when a gap is placed.Comment: 25 pages, 11 captioned figures, 3 tables, authors from page 20,
published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/87
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