20,167 research outputs found
Renewal theory of coupled neuronal pools
A theory is provided to analyze the dynamics of delay-coupled pools of spiking neurons based on stability
analysis of stationary firing. Transitions between stable and unstable regimes can be predicted by bifurcation analysis of the underlying integral dynamics. Close to the bifurcation point the network exhibits slowly changingactivities and allows for slow collective phenomena like continuous attractors
Quantum confinement effects in Si/Ge heterostructures with spatially ordered arrays of self-assembled quantum dots
Magnetotunneling spectroscopy was employed to probe the confinement in
vertical Si/Ge double-barrier resonant tunneling diodes with regularly
distributed Ge quantum dots. Their current-voltage characteristics reveal a
step-like behavior in the vicinity of zero bias, indicating resonant tunneling
of heavy-holes via three-dimensionally confined unoccupied hole states in Ge
quantum dots. Assuming parabolic confinement we extract the strength of the
confinement potential of quantum dots.Comment: 4 pages, 3 figure
Chirurgie der Hyperthyreose
Pathophysiologie, Diagnostik, Operationsindikation und Vorbehandlung, chirurgisches Krankengut, Operationsverfahren und Nachbehandlung mit funktionellen Spätergebnissen wurden gezeigt. Der ätiologisch bedingte Unterschied in Therapie und Prognose der Hyperthyreose vom Typ des M. Basedow gegenüber den anderen Hyperthyreoseformen war dargestellt. Von 1891 schilddrüsenoperierten Patienten in den letzten 10 Jahren waren fast (n = 625) hyperthyreot; 22,7% der Hyperthyreosen waren vom Typ des M. Basedow, 26,5 % multinoduläre Strumen, der Rest autonome AdenomePathophysiology, diagnosis, indication for operation and pretreatment, data of operated patients, surgical treatment, and postoperative care with late results are demonstrated. The differences between Graves' disease and other kinds of hyperthyroidism are pointed out. About (n = 625) of all patients operated upon for goiter (n= 1891) within the last ten years had hyperthyroidism. Exophthalmia was present in 22.7 %, toxic multinodular goiter in 26.5 %; the rest of the patients had autonomous adenoma. The importance of radioimmunoassays to determine preoperative treatment and postoperative hormone levels for long-term results is stressed
Enhanced nonperturbative effects in jet distributions
We consider the triple differential distribution
d\Gamma/(dE_J)(dm_J^2)(d\Omega_J) for two-jet events at center of mass energy
M, smeared over the endpoint region m_J^2 << M^2, |2 E_J -M| ~ \Delta, \lqcd <<
\Delta << M. The leading nonperturbative correction, suppressed by
\lqcd/\Delta, is given by the matrix element of a single operator. A similar
analysis is performed for three jet events, and the generalization to any
number of jets is discussed. At order \lqcd/\Delta, non-perturbative effects in
four or more jet events are completely determined in terms of two matrix
elements which can be measured in two and three jet events.Comment: Significant changes made. The first moment does not vanish--the paper
has been modified to reflect this. Relations between different numbers of
jets still hol
An evolutionary perspective on the kinome of malaria parasites
Malaria parasites belong to an ancient lineage that diverged very early from the main branch of eukaryotes. The approximately 90-member plasmodial kinome includes a majority of eukaryotic protein kinases that clearly cluster within the AGC, CMGC, TKL, CaMK and CK1 groups found in yeast, plants and mammals, testifying to the ancient ancestry of these families. However, several hundred millions years of independent evolution, and the specific pressures brought about by first a photosynthetic and then a parasitic lifestyle, led to the emergence of unique features in the plasmodial kinome. These include taxon-restricted kinase families, and unique peculiarities of individual enzymes even when they have homologues in other eukaryotes. Here, we merge essential aspects of all three malaria-related communications that were presented at the Evolution of Protein Phosphorylation meeting, and propose an integrated discussion of the specific features of the parasite's kinome and phosphoproteome
A non-geodesic motion in the R^-1 theory of gravity tuned with observations
In the general picture of high order theories of gravity, recently, the R^-1
theory has been analyzed in two different frameworks. In this letter a third
context is added, considering an explicit coupling between the R^-1 function of
the Ricci scalar and the matter Lagrangian. The result is a non-geodesic motion
of test particles which, in principle, could be connected with Dark Matter and
Pioneer anomaly problems.Comment: Accepted for Modern Physics Letters
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