184 research outputs found
Das Duopol der legitimen Gewalt im schweizerischen Bundesstaat : zwei Fallstudien zu Armee und Polizei
Das Monopol der legitimen Gewalt ist ein wichtiges Merkmal des modernen, souveränen Staates. Doch handelt es sich eigentlich um ein Duopol, denn diese Gewalt ist zwischen Armee und Polizei aufgeteilt. Diese Trennung ist für die Modernisierung der Gesellschaft ebenfalls zentral, unterliegen doch die beiden Corps völlig andern Einsatzdoktrinen. Doch wie steht es damit nun im Bundesstaat, in welchem auch den Gliedern staatliche Qualität zukommt? Vereinfacht lautet die Antwort: Die Armee dem Bund, die Polizei den Kantonen. Doch bei der Gründung des schweizerischen Bundesstaates hatten die Kantone noch bedeutende Kompetenzen im Bereich der Armee. Die Studie zeigt, wann und nach welcher Logik diese im Laufe der Zeit an den Bund übertragen worden sind. Komplizierter ist es bei der Polizei, wo gewisse Aufgaben ebenfalls schon früh an den Bund übergegangen sind, die Kantone jedoch das Gros der Kompetenzen behalten haben. Dazu kommt, dass die Armee im Rahmen ,,subsidiärer Einsätze" auch immer wieder polizeiliche Aufgaben übernimmt. Mittels einer funktionalen Analyse erarbeitet der zweite Teil der Studie Kriterien für eine optimale Aufgabenteilung.
Le monopole de la violence légitime est une caractéristique importante de l'Etat souverain moderne. En réalité il s'agit d'un duopole, puisque l'armée et la police se partagent les moyens de force. Cette séparation est essentielle pour la modernisation des sociétés. Les doctrines de mission des deux corps se distinguent profondément. Comment ce duopole se présente-t-il dans un Etat fédéral qui est caractérisé par deux niveaux étatiques ? Réponse simplifiée : L'Etat central dispose de l'armée, les Etats fédérés de la police. La réalité est plus complexe : Lors de la création de l'Etat moderne en 1848, les compétences des Cantons dans le domaine de la défense furent encore considérables. L'étude retrace les étapes et les causes de la perte de ces attributions. Les compétences policières sont par contre largement restées auprès des Cantons, mais les attributions de la police fédérale s'élargissent continuellement, les gardes-frontières collaborent avec les polices cantonales et les missions subsidiaires de l'armée se multiplient. L'attribution des tâches policières et les modes de collaboration entre Cantons et Confédération sont depuis un certain temps déjà en discussion. L'étude donne quelques critères pour une répartition fonctionnelle.
Selon quels critères fonctionnels se « partage des pouvoirs » devrait-il être organisé ? La deuxième partie de l'étude donne quelques réponses
An Approximation for the rp-Process
Hot (explosive) hydrogen burning or the Rapid Proton Capture Process
(rp-process) occurs in a number of astrophysical environments. Novae and X-ray
bursts are the most prominent ones, but accretion disks around black holes and
other sites are candidates as well. The expensive and often multidimensional
hydro calculations for such events require an accurate prediction of the
thermonuclear energy generation, while avoiding full nucleosynthesis network
calculations. In the present investigation we present an approximation scheme
applicable in a temperature range which covers the whole range of all presently
known astrophysical sites. It is based on the concept of slowly varying
hydrogen and helium abundances and assumes a kind of local steady flow by
requiring that all reactions entering and leaving a nucleus add up to a zero
flux. This scheme can adapt itself automatically and covers situations at low
temperatures, characterized by a steady flow of reactions, as well as high
temperature regimes where a -equilibrium is established.
In addition to a gain of a factor of 15 in computational speed over a full
network calculation, and an energy generation accurate to more than 15 %, this
scheme also allows to predict correctly individual isotopic abundances. Thus,
it delivers all features of a full network at a highly reduced cost and can
easily be implemented in hydro calculations.Comment: 18 pages, LaTeX using astrobib and aas2pp4, includes PostScript
figures; Astrophysical Journal, in press. PostScript source also available at
http://quasar.physik.unibas.ch/preps.htm
Changes in r-process abundances at late times
We explore changes in abundance patterns that occur late in the r process. As
the neutrons available for capture begin to disappear, a quasiequilibrium
funnel shifts material into the large peaks at A=130 and A=195, and into the
rare-earth "bump" at A=160. A bit later, after the free-neutron abundance has
dropped and beta-decay has begun to compete seriously with neutron capture, the
peaks can widen. The degree of widening depends largely on neutron-capture
rates near closed neutron shells and relatively close to stability. We identify
particular nuclei the capture rates of which should be examined experimentally,
perhaps at a radioactive beam facility.Comment: 8 pages, 14 figures included in tex
Integrated Nucleosynthesis in Neutrino Driven Winds
Although they are but a small fraction of the mass ejected in core-collapse
supernovae, neutrino-driven winds (NDWs) from nascent proto-neutron stars
(PNSs) have the potential to contribute significantly to supernova
nucleosynthesis. In previous works, the NDW has been implicated as a possible
source of r-process and light p-process isotopes. In this paper we present
time-dependent hydrodynamic calculations of nucleosynthesis in the NDW which
include accurate weak interaction physics coupled to a full nuclear reaction
network. Using two published models of PNS neutrino luminosities, we predict
the contribution of the NDW to the integrated nucleosynthetic yield of the
entire supernova. For the neutrino luminosity histories considered, no true
r-process occurs in the most basic scenario. The wind driven from an older model for a PNS is moderately neutron-rich at late times however, and
produces Rb, Sr, Y, and Zr in near solar
proportions relative to oxygen. The wind from a more recently studied PNS is proton-rich throughout its entire evolution and does not
contribute significantly to the abundance of any element. It thus seems very
unlikely that the simplest model of the NDW can produce the r-process. At most,
it contributes to the production of the N = 50 closed shell elements and some
light p-nuclei. In doing so, it may have left a distinctive signature on the
abundances in metal poor stars, but the results are sensitive to both uncertain
models for the explosion and the masses of the neutron stars involved.Comment: 18 Pages, 14 Figures, Astrophysical Journal (Submitted 4/16/10
Short- and Long-Term Effects of High-Intensity Interval Training vs. Moderate-Intensity Continuous Training on Left Ventricular Remodeling in Patients Early After ST-Segment Elevation Myocardial Infarction-The HIIT-EARLY Randomized Controlled Trial.
Aim
Due to insufficient evidence on the safety and effectiveness of high-intensity interval training (HIIT) in patients early after ST-segment elevation myocardial infarction (STEMI), we aimed to compare short- and long-term effects of randomized HIIT or moderate-intensity continuous training (MICT) on markers of left ventricular (LV) remodeling in STEMI patients receiving optimal guideline-directed medical therapy (GDMT).
Materials and Methods
Patients after STEMI (<4 weeks) enrolled in a 12-week cardiac rehabilitation (CR) program were recruited for this randomized controlled trial (NCT02627586). During a 3-week run-in period with three weekly MICT sessions, GDMT was up-titrated. Then, the patients were randomized to HIIT or isocaloric MICT for 9 weeks. Echocardiography and cardiopulmonary exercise tests were performed after run-in (3 weeks), end of CR (12 weeks), and at 1-year follow-up. The primary outcome was LV end-diastolic volume index (LVEDVi) at the end of CR. Secondary outcomes were LV global longitudinal strain (GLS) and cardiopulmonary fitness.
Results
Seventy-three male patients were included, with the time between STEMI and start of CR and randomization being 12.5 ± 6.3 and 45.8 ± 10.8 days, respectively. Mixed models revealed no significant group × time interaction for LVEDVi at the end of CR (p = 0.557). However, there was a significantly smaller improvement in GLS at 1-year follow-up in the HIIT compared to the MICT group (p = 0.031 for group × time interaction). Cardiorespiratory fitness improved significantly from a median value of 26.5 (1st quartile 24.4; 3rd quartile 1.1) ml/kg/min at randomization in the HIIT and 27.7 (23.9; 31.6) ml/kg/min in the MICT group to 29.6 (25.3; 32.2) and 29.9 (26.1; 34.9) ml/kg/min at the end of CR and to 29.0 (26.6; 33.3) and 30.6 (26.0; 33.8) ml/kg/min at 1 year follow-up in HIIT and MICT patients, respectively, with no significant group × time interactions (p = 0.138 and 0.317).
Conclusion
In optimally treated patients early after STEMI, HIIT was not different from isocaloric MICT with regard to short-term effects on LVEDVi and cardiorespiratory fitness. The worsening in GLS at 1 year in the HIIT group deserves further investigation, as early HIIT may offset the beneficial effects of GDMT on LV remodeling in the long term
Explosive nucleosynthesis in core-collapse supernovae
The specific mechanism and astrophysical site for the production of half of
the elements heavier than iron via rapid neutron capture (r-process) remains to
be found. In order to reproduce the abundances of the solar system and of the
old halo stars, at least two components are required: the heavy r-process
nuclei (A>130) and the weak r-process which correspond to the lighter heavy
nuclei (A<130). In this work, we present nucleosynthesis studies based on
trajectories of hydrodynamical simulations for core-collapse supernovae and
their subsequent neutrino-driven winds. We show that the weak r-process
elements can be produced in neutrino-driven winds and we relate their
abundances to the neutrino emission from the nascent neutron star. Based on the
latest hydrodynamical simulations, heavy r-process elements cannot be
synthesized in the neutrino-driven winds. However, by artificially increasing
the wind entropy, elements up to A=195 can be made. In this way one can mimic
the general behavior of an ejecta where the r-process occurs. We use this to
study the impact of the nuclear physics input (nuclear masses, neutron capture
cross sections, and beta-delayed neutron emission) and of the long-time
dynamical evolution on the final abundances.Comment: 10 pages, 8 figures, invited talk, INPC 2010 Vancouver, Journal of
Physics: Conference Serie
Neutrino signatures and the neutrino-driven wind in Binary Neutron Star Mergers
We present VULCAN/2D multi-group flux-limited-diffusion radiation
hydrodynamics simulations of binary neutron star (BNS) mergers, using the Shen
equation of state, covering ~100 ms, and starting from azimuthal-averaged 2D
slices obtained from 3D SPH simulations of Rosswog & Price for 1.4 Msun
(baryonic) neutron stars with no initial spins, co-rotating spins, and
counter-rotating spins. Snapshots are post-processed at 10 ms intervals with a
multi-angle neutrino-transport solver. We find polar-enhanced neutrino
luminosities, dominated by and ``'' neutrinos at peak,
although emission may be stronger at late times. We obtain typical peak
neutrino energies for , , and ``'' of ~12, ~16,
and ~22 MeV. The super-massive neutron star (SMNS) formed from the merger has a
cooling timescale of ~1 s. Charge-current neutrino reactions lead to the
formation of a thermally-driven bipolar wind with ~10
Msun/s, baryon-loading the polar regions, and preventing any production of a
GRB prior to black-hole formation. The large budget of rotational free energy
suggests magneto-rotational effects could produce a much greater polar mass
loss. We estimate that ~10 Msun of material with electron fraction in
the range 0.1-0.2 become unbound during this SMNS phase as a result of neutrino
heating. We present a new formalism to compute the
annihilation rate based on moments of the neutrino specific intensity computed
with our multi-angle solver. Cumulative annihilation rates, which decay as
, decrease over our 100 ms window from a few 10 to ~10
erg/s, equivalent to a few 10 to ~10 pairs per second.Comment: 23 pages, 20 figures, 2 tables, submitted to ApJ, high resolution
version of the paper available at http://hermes.as.arizona.edu/~luc/ms.pd
Accurate evolutions of unequal-mass neutron-star binaries: properties of the torus and short GRB engines
We present new results from accurate and fully general-relativistic
simulations of the coalescence of unmagnetized binary neutron stars with
various mass ratios. The evolution of the stars is followed through the
inspiral phase, the merger and prompt collapse to a black hole, up until the
appearance of a thick accretion disk, which is studied as it enters and remains
in a regime of quasi-steady accretion. Although a simple ideal-fluid equation
of state with \Gamma=2 is used, this work presents a systematic study within a
fully general relativistic framework of the properties of the resulting
black-hole--torus system produced by the merger of unequal-mass binaries. More
specifically, we show that: (1) The mass of the torus increases considerably
with the mass asymmetry and equal-mass binaries do not produce significant tori
if they have a total baryonic mass M_tot >~ 3.7 M_sun; (2) Tori with masses
M_tor ~ 0.2 M_sun are measured for binaries with M_tot ~ 3.4 M_sun and mass
ratios q ~ 0.75-0.85; (3) The mass of the torus can be estimated by the simple
expression M_tor(q, M_tot) = [c_1 (1-q) + c_2](M_max-M_tot), involving the
maximum mass for the binaries and coefficients constrained from the
simulations, and suggesting that the tori can have masses as large as M_tor ~
0.35 M_sun for M_tot ~ 2.8 M_sun and q ~ 0.75-0.85; (4) Using a novel technique
to analyze the evolution of the tori we find no evidence for the onset of
non-axisymmetric instabilities and that very little, if any, of their mass is
unbound; (5) Finally, for all the binaries considered we compute the complete
gravitational waveforms and the recoils imparted to the black holes, discussing
the prospects of detection of these sources for a number of present and future
detectors.Comment: 35 pages; small changes to match the published versio
The effects of r-process heating on fall-back accretion in compact object mergers
We explore the effects of r-process nucleosynthesis on fall-back accretion in
neutron star(NS)-NS and black hole-NS mergers, and the resulting implications
for short-duration gamma-ray bursts (GRBs). Though dynamically important, the
energy released during the r-process is not yet taken into account in merger
simulations. We use a nuclear reaction network to calculate the heating (due to
beta-decays and nuclear fission) experienced by material on the
marginally-bound orbits nominally responsible for late-time fall-back. Since
matter with longer orbital periods t_orb experiences lower densities, for
longer periods of time, the total r-process heating rises rapidly with t_orb,
such that material with t_orb > 1 seconds can become completely unbound. Thus,
r-process heating fundamentally changes the canonical prediction of an
uninterrupted power-law decline in the fall-back rate dM/dt at late times. When
the timescale for r-process to complete is > 1 second, the heating produces a
complete cut-off in fall-back accretion after ~ 1 second; if robust, this would
imply that fall-back accretion cannot explain the late-time X-ray flaring
observed following some short GRBs. However, for a narrow, but physically
plausible, range of parameters, fall-back accretion can resume after ~ 10 s,
despite having been strongly suppressed for ~ 1-10 s after the merger. This
suggests the intriguing possibility that the gap observed between the prompt
and extended emission in short GRBs is a manifestation of r-process heating.Comment: 7 pages; 4 figures; submitted to MNRA
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