600 research outputs found
Positive Beurteilung der schweizerischen Lehrerfortbildung (und Lehrergrundausbildung) im Computer-/Informatikbereich im internationalen Vergleich
Die Lehrerinnen und Lehrer der Schweiz beurteilen die Einführung als gut, die sie für die Benutzung der Computer im Unterricht erhalten haben. Das geht aus der Stellungnahme von 5\u27000 Personen hervor, die im 7. bis 13. Schuljahr unterrichten. Die Daten sind wesentlich positiver als in anderen Ländern. Das Ergebnis ist eine erfreuliche Bestätigung für die Lehrerfortbildung, die Projektgruppen zur Informatikeinführung und für die Lehrergrundausbildung. Zudem signalisiert es auch eine gute Basis für weitere Innovationen. Merkwürdigerweise meinen die vorgesetzten Rektoren und Informatikzuständigen, die Lehrer dürften noch mehr wissen und können. Wir legen die entsprechenden Daten vor und formulieren einige Vermutungen zu diesem paradoxen Phänomen
Probing the qudit depolarizing channel
For the quantum depolarizing channel with any finite dimension, we compare
three schemes for channel identification: unentangled probes, probes maximally
entangled with an external ancilla, and maximally entangled probe pairs. This
comparison includes cases where the ancilla is itself depolarizing and where
the probe is circulated back through the channel before measurement. Compared
on the basis of (quantum Fisher) information gained per channel use, we find
broadly that entanglement with an ancilla dominates the other two schemes, but
only if entanglement is cheap relative to the cost per channel use and only if
the external ancilla is well shielded from depolarization. We arrive at these
results by a relatively simple analytical means. A separate, more complicated
analysis for partially entangled probes shows for the qudit depolarizing
channel that any amount of probe entanglement is advantageous and that the
greatest advantage comes with maximal entanglement
Quantum Energy Teleportation between Spin Particles in a Gibbs State
Energy in a multipartite quantum system appears from an operational
perspective to be distributed to some extent non-locally because of
correlations extant among the system's components. This non-locality allows
users to transfer, in effect, locally accessible energy between sites of
different system components by LOCC (local operations and classical
communication). Quantum energy teleportation is a three-step LOCC protocol,
accomplished without an external energy carrier, for effectively transferring
energy between two physically separated, but correlated, sites. We apply this
LOCC teleportation protocol to a model Heisenberg spin particle pair initially
in a quantum thermal Gibbs state, making temperature an explicit parameter. We
find in this setting that energy teleportation is possible at any temperature,
even at temperatures above the threshold where the particles' entanglement
vanishes. This shows for Gibbs spin states that entanglement is not
fundamentally necessary for energy teleportation; correlation other than
entanglement can suffice. Dissonance---quantum correlation in separable
states---is in this regard shown to be a quantum resource for energy
teleportation, more dissonance being consistently associated with greater
energy yield. We compare energy teleportation from particle A to B in Gibbs
states with direct local energy extraction by a general quantum operation on B
and find a temperature threshold below which energy extraction by a local
operation is impossible. This threshold delineates essentially two regimes: a
high temperature regime where entanglement vanishes and the teleportation
generated by other quantum correlations yields only vanishingly little energy
relative to local extraction and a second low-temperature teleportation regime
where energy is available at B only by teleportation
Der Übergang eines Schülerjahrgangs in das Ausbildungssystem. Untersuchung zur realisierten Ausbildungsnachfrage Jugendlicher in Ostfriesland
Ziel der im Herbst 1977 und 1978 im Auftrag des Niedersächsischen Kultusministeriums durchgeführten Untersuchung war es, "für eine wirtschaftsstrukturschwache Region mit einem überdurchschnittlich hohen Anteil von Jugendlichen, die quantitative Dimension der Versorgung mit Ausbildungsplätzen zu bestimmen und Informationen über das Bewerbungsverhalten derjenigen zu bekommen, die nicht in eine Ausbildung eintraten."Ausbildungsplatzangebot, Bewerbungsverhalten, Schulabgänger, Ausbildungsverzicht, Ausbildungsplatznachfrage, strukturschwache Räume, Wirtschaftsstruktur, Ostfriesland, Niedersachsen, Aurich
Interactions mediated by a public good transiently increase cooperativity in growing Pseudomonas putida metapopulations
Bacterial communities have rich social lives. A well-established interaction involves the exchange of a public good in Pseudomonas populations, where the iron-scavenging compound pyoverdine, synthesized by some cells, is shared with the rest. Pyoverdine thus mediates interactions between producers and non-producers and can constitute a public good. This interaction is often used to test game theoretical predictions on the "social dilemma" of producers. Such an approach, however, underestimates the impact of specific properties of the public good, for example consequences of its accumulation in the environment. Here, we experimentally quantify costs and benefits of pyoverdine production in a specific environment, and build a model of population dynamics that explicitly accounts for the changing significance of accumulating pyoverdine as chemical mediator of social interactions. The model predicts that, in an ensemble of growing populations (metapopulation) with different initial producer fractions (and consequently pyoverdine contents), the global producer fraction initially increases. Because the benefit of pyoverdine declines at saturating concentrations, the increase need only be transient. Confirmed by experiments on metapopulations, our results show how a changing benefit of a public good can shape social interactions in a bacterial population
Glucocorticoid sensitivity of circulating monocytes in essential hypertension
Background: Essential hypertension ranks among the strongest cardiovascular risk factors. Cytokine production by monocytes plays a key role in atherosclerosis development and acute coronary syndromes. We investigated whether stimulated monocyte cytokine release and its inhibition by glucocorticoids would differ between hypertensive and normotensive subjects. Methods: Study participants were 222 middle-aged male employees with industrial jobs. Following the criteria of the World Health Organization/International Society for Hypertension, 76 subjects were classified as being hypertensive (systolic blood pressure ≥140 mm Hg or diastolic blood pressure ≥90 mm Hg). In vitro monocyte tumor necrosis factor (TNF)-α release after lipopolysaccharide (LPS) stimulation was assessed with and without coincubation with incremental doses of dexamethasone. Monocyte glucocorticoid sensitivity was defined as the dexamethasone concentration inhibiting TNF-α release by 50%. Results: Hypertensive subjects showed 11% higher LPS-stimulated TNF-α release than normotensive subjects (F1,181= 5.21, P = .024). In hypertensive subjects, monocyte glucocorticoid sensitivity was 21% lower than in normotensive subjects (F1,178= 4.94, P = .027), indicating that dexamethasone inhibited relatively less TNF-α release in hypertensive subjects. Results held significance when a set of classic cardiovascular risk factors was controlled for. Conclusion: The findings suggest that proinflammatory activity of circulating monocytes is higher in hypertensive than in normotensive men, providing one potential pathway to explain the increased atherosclerotic risk with essential hypertension. Am J Hypertens 2004;17:489-494 © 2004 American Journal of Hypertension, Lt
Was verstehen Sie unter Fachdidaktik? Expert(inn)en-Befragung zur Fachdidakktik und zur Fachdidaktiker(innen)-Ausbildung
Die Auffassungen über das (Wissenschafts-)Verständnis von Fachdidaktik, über ihre Abgrenzung von Nachbardisziplinen, über ihre Funktion in der Lehrer(innen)bildung und über die Aus- und Fortbildungsstrukturen und -inhalte von Fachdidaktiker(inne)n sind durchaus nicht einheitlich. Sie dürften u.a. wesentlich davon abhängen, aus welchem beruflichen Blickwinkel man sich mit dem Gebiet beschäftigt und welche Fachbereiche und Ausbildungsstufen man dabei im Auge hat. nWir legten sechs Expert(inn)en, Leiterinnen und Leitern von Instituten, an denen Lehrer(innen) verschiedener Stufen und Fachbereiche ausgebildet werden, je vier Fragen zu den obigen Problemkreisen vor, die sie in schriftlichen Statements beantworteten. nProf. Dr. Rudolf Künzli, Rektor des Aargauischen Instituts für Bezirkslehrer/innen- Bildung (Didaktikum) und selber Experte in erziehungswissenschaftlichen Fragen, hat die "Interview"-Beiträge gesichtet, Gemeinsamkeiten und Unterschiede in den Expert(inn)en-Antworten ausgemacht und einen wissenschaftskritischen Kommentar aus seiner Sicht beigefügt
Expression of the synthetic gene of an artificial DDT-binding polypeptide in Escherichia coli
This paper reports the expression of an artificial functional polypeptide in bacteria. The gene of a designed 24-residue DDT-binding polypeptide (DBP) was inserted between the BamHI and PstI cleavage sites of plasmid pUR291. The hybrid plasmid, pUR291-DBP, was cloned in Escherichia coli JM109. After induction by isopropyl-β-D-thiogalactopyranoside a fusion protein was expressed in which DBP was linked to the COOH-termiuus of β-galactosidase. DBP, which is stable to trypsin, was obtained by tryptic digestion of the fusion protein and subsequent fractionation of the tryptic peptides by reversed-phase h.p.l.c. Recombinant and chemically synthesized DBP showed identical chromatographic properties, amino acid composition, and chymotryptic digestion patterns. Both the β-galactosidase-DBP fusion and isolated recombinant DBP bound DDT. The fusion protein was 25 times as potent as the designed 24-residue DBP in activating a cytochrome P-450 model system using equimolar catalytic amounts of the two protein
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