7,164 research outputs found
Politica mondiale e pathos nazionale
II concetto di "nazione" rimanda sempre alla relazione con la "potenza"
politica; ed evidentemente, se "nazionale" deve significare qualcosa di unitario,
allora "nazionale" sarà anche uno speciale pathos che, in un gmppo di
uomini uniti dalla comunità di lingua, dalla confessione, dai costumi o dai
destini si ricollega all'idea di una propria organizzazione politica rivolta alla
"potenza", già esistente o auspicata; e ciò tanto più specificamente quanto più
l'accento viene posto sulla "potenza". Di fronte alla molteplicità di significato,
empiricamente riscontrabile, del concetto di valore costituito dall'idea di
nazione", una casistica sociologica dovrebbe sviluppare un'analisi di tutte le
singole forme di sentimenti di comunanza e di solidarietà, per individuare le
condizioni in cui esse si producono e le loro conseguenze sull'agire di comunità
dei partecipanti.
Questa analisi non può essere tentata in questa sede. Piuttosto ci interessa
esaminare ancora un po' più da vicino un altro fenomeno, cioè il fatto che l'idea
di "nazione" si trova, nei suoi portatori, in relazioni molto strette con determinati
interessi di "prestigio"
A Constrained EM Algorithm for Independent Component Analysis
We introduce a novel way of performing independent component analysis using a constrained version of the expectation-maximization (EM) algorithm. The source distributions are modeled as D one-dimensional mixtures of gaussians. The observed data are modeled as linear mixtures of the sources with additive, isotropic noise. This generative model is fit to the data using constrained EM. The simpler “soft-switching” approach is introduced, which uses only one parameter to decide on the sub- or supergaussian nature of the sources. We explain how our approach relates to independent factor analysis
Collective treatment of the giant resonances in spherical nuclei
In a collective treatment the energies of the giant resonances are given by the boundary conditions at the nuclear surface, which is subject to vibration in spherical nuclei. The general form of the coupling between these two collective motions is given by angular-momentum and parity conservation. The coupling constants are completely determined within the hydrodynamical model. In the present treatment the influence of the surface vibrations on the total photon-absorption cross section is calculated. It turns out that in most of the spherical nuclei this interaction leads to a pronounced structure in the cross section. The agreement with the experiments in medium-heavy nuclei is striking; many of the experimental characteristics are reproduced by the present calculations. In some nuclei, however, there seem to be indications of single-particle excitations which are not yet contained in this work
Field dependence of non-reciprocal magnons in chiral MnSi
Spin waves in chiral magnetic materials are strongly influenced by the
Dzyaloshinskii-Moriya interaction resulting in intriguing phenomena like
non-reciprocal magnon propagation and magnetochiral dichroism. Here, we study
the non-reciprocal magnon spectrum of the archetypical chiral magnet MnSi and
its evolution as a function of magnetic field covering the field-polarized and
conical helix phase. Using inelastic neutron scattering, the magnon energies
and their spectral weights are determined quantitatively after deconvolution
with the instrumental resolution. In the field-polarized phase the imaginary
part of the dynamical susceptibility is shown to
be asymmetric with respect to wavevectors longitudinal to the applied
magnetic field , which is a hallmark of chiral magnetism. In the
helimagnetic phase, becomes increasingly
symmetric with decreasing due to the formation of helimagnon bands
and the activation of additional spinflip and non-spinflip scattering channels.
The neutron spectra are in excellent quantitative agreement with the low-energy
theory of cubic chiral magnets with a single fitting parameter being the
damping rate of spin waves.Comment: Paper: 10 pages, 5 figures Supplement: 8 pages, 11 figure
The host galaxies of strong CaII QSO absorption systems at z<0.5
We present new imaging and spectroscopic observations of the fields of five
QSOs with very strong intervening CaII absorption systems at redshifts z<0.5
selected from the Sloan Digital Sky Survey. Recent studies of these very rare
absorbers indicate that they may be related to damped Lyman alpha systems
(DLAs). In all five cases we identify a galaxy at the redshift of the CaII
system with impact parameters up to ~24 kpc. In four out of five cases the
galaxies are luminous (L ~L*), metal-rich (Z ~Zsun), massive (velocity
dispersion, sigma ~100 km/s) spirals. Their star formation rates, deduced from
Halpha emission, are high, in the range SFR = 0.3 - 30 Msun/yr. In our
analysis, we paid particular attention to correcting the observed emission line
fluxes for stellar absorption and dust extinction. We show that these effects
are important for a correct SFR estimate; their neglect in previous low-z
studies of DLA-selected galaxies has probably led to an underestimate of the
star formation activity in at least some DLA hosts. We discuss possible links
between CaII-selected galaxies and DLAs and outline future observations which
will help clarify the relationship between these different classes of QSO
absorbers.Comment: Accepted for publication in MNRAS, 14 pages, 9 figures. Version with
full resolution images available at
http://www.ast.cam.ac.uk/~bjz/papers/Zych_etal_2007a.pd
Elective affinities of the Protestant ethic : Weber and the chemistry of capitalism
Peer reviewedPostprin
Differential contractile response of critically ill patients to neuromuscular electrical stimulation
BACKGROUND:
Neuromuscular electrical stimulation (NMES) has been investigated as a preventative measure for intensive care unit-acquired weakness. Trial results remain contradictory and therefore inconclusive. As it has been shown that NMES does not necessarily lead to a contractile response, our aim was to characterise the response of critically ill patients to NMES and investigate potential outcome benefits of an adequate contractile response.
METHODS:
This is a sub-analysis of a randomised controlled trial investigating early muscle activating measures together with protocol-based physiotherapy in patients with a SOFA score ≥ 9 within the first 72 h after admission. Included patients received protocol-based physiotherapy twice daily for 20 min and NMES once daily for 20 min, bilaterally on eight muscle groups. Electrical current was increased up to 70 mA or until a contraction was detected visually or on palpation. Muscle strength was measured by a blinded assessor at the first adequate awakening and ICU discharge.
RESULTS:
One thousand eight hundred twenty-four neuromuscular electrical stimulations in 21 patients starting on day 3.0 (2.0/6.0) after ICU admission were included in this sub-analysis. Contractile response decreased from 64.4% on day 1 to 25.0% on day 7 with a significantly lower response rate in the lower extremities and proximal muscle groups. The electrical current required to elicit a contraction did not change over time (day 1, 50.2 [31.3/58.8] mA; day 7, 45.3 [38.0/57.5] mA). The electrical current necessary for a contractile response was higher in the lower extremities. At the first awakening, patients presented with significant weakness (3.2 [2.5/3.8] MRC score). When dividing the cohort into responders and non-responders (> 50% vs. ≤ 50% contractile response), we observed a significantly higher SOFA score in non-responders. The electrical current necessary for a muscle contraction in responders was significantly lower (38.0 [32.8/42.9] vs. 54.7 [51.3/56.0] mA, p < 0.001). Muscle strength showed higher values in the upper extremities of responders at ICU discharge (4.4 [4.1/4.6] vs. 3.3 [2.8/3.8] MRC score, p = 0.036).
CONCLUSION:
Patients show a differential contractile response to NMES, which appears to be dependent on the severity of illness and also relevant for potential outcome benefits.
TRIAL REGISTRATION:
ISRCTN ISRCTN19392591 , registered 17 February 201
A galaxy as the source of a Civ absorption system close to the epoch of reionization
We find a bright (L_{UV}=2.5 L*_{z=6}) Lyman alpha emitter at redshift
z=5.719 at a projected distance of 79 physical kpc from a strong triply ionized
carbon (Civ) absorption system at redshift z=5.7238 previously reported in the
spectrum of the z_{em} = 6.309 QSO SDSS J1030+0524. This is the highest
redshift galaxy-absorber pair detected to-date, supporting the idea that
galaxy-wide outflows were already in place at the end of the epoch of
reionization. The proximity of this object makes it the most likely source of
metals, consistent with models of outflows at lower redshift where significant
observational evidence relates metal absorption systems with galaxies hosting
outflows.
In a typical outflow scenario, a wind of 200 km/s, active since the universe
was only 0.6 Gyr old (z ~8.4), could eject metals out to 79 kpc at z=5.719.
Although the origin of metals in the intergalactic medium (IGM) is still under
debate, our results are consistent with predictions from cosmological
simulations which reproduce the evolution of the cosmic density of Civ, from z
~ 6 to the present day based on outflow-driven enrichment of the IGM.
We also report two more Lyman alpha emitters in this field, at z=5.973\pm
0.002 and z=5.676\pm 0.002 respectively, the former confirming the original
identification by Stiavelli et al. Our results suggest that the colour cut
typically used to identify i-dropouts (i_{775}-z_{850}>1.3) misses a
non-negligible fraction of blue galaxies with faint UV continuum at z \geq 5.7.Comment: Accepted for publication in MNRAS, 9 pages, 3 figures, 1 tabl
- …
