22,589 research outputs found
The reported use and effectiveness of Hypericum (St John’s wort) on affective symptoms in a depression self-help group
A recent meta-analysis suggested that Hypericum
perforatum (St John’s wort) is an effective
treatment for mild to moderate depression and
may have a superior side-effect profile to some
antidepressant drugs. The aim of this study was to
assess the use of herbal remedies in treating
depressive and anxiety symptoms, as reported by
members of the UK self-help organization
Depression Alliance using self-completed
questionnaires. More than 50% of the 452
respondents reported using Hypericum, onequarter
of whom also reported concurrent use of
traditional antidepressants. Most of the sample
reported sufficient symptoms for warranting a
diagnosis of major depression, with the majority
also describing symptoms suggestive of co-morbid
psychiatric conditions. One-half of the Hypericum
users experienced symptom improvement, which
for most occurred within the first 4 weeks of use.
Response was better for those with mild as
compared to severe symptoms and poorer for
those taking Hypericum alongside other
antidepressants. The responders were generally
older than non-responders. Adverse effects were
reported by one-quarter of users and were mostly
psychological in nature. This retrospective survey
indicated that use of herbal remedies was
common in this population. Although often helpful
in relieving symptoms, particularly in those with
mild depression, there is a risk of adverse events
and drug interaction
Spin-Flavor Structure of Large N Baryons
The spin-flavor structure of large N baryons is described in the 1/N
expansion of QCD using quark operators. The complete set of quark operator
identities is obtained, and used to derive an operator reduction rule which
simplifies the 1/N expansion. The operator reduction rule is applied to the
axial currents, masses, magnetic moments and hyperon non-leptonic decay
amplitudes in the limit, to first order in breaking, and
without assuming symmetry. The connection between the Skyrme and quark
representations is discussed. An explicit formula is given for the quark model
operators in terms of the Skyrme model operators to all orders in for
the two flavor case.Comment: 36 pages, 2 eps figures, uses revte
On the structure of large N cancellations in baryon chiral perturbation theory
We show how to compute loop graphs in heavy baryon chiral perturbation theory
including the full functional dependence on the ratio of the Delta--nucleon
mass difference to the pion mass, while at the same time automatically
incorporating the 1/N cancellations that follow from the large-N spin-flavor
symmetry of baryons in QCD. The one-loop renormalization of the baryon axial
vector current is studied to demonstrate the procedure. A new cancellation is
identified in the one-loop contribution to the baryon axial vector current. We
show that loop corrections to the axial vector currents are exceptionally
sensitive to deviations of the ratios of baryon-pion axial couplings from SU(6)
values
VTOL in ground effect flows for closely spaced jets
Results of a series of in ground effect twin jet tests are presented along with flow models for closely spaced jets to help predict pressure and upwash forces on simulated aircraft surfaces. The isolated twin jet tests revealed unstable fountains over a range of spacings and jet heights, regions of below ambient pressure on the ground, and negative pressure differential in the upwash flow field. A separate computer code was developed for vertically oriented, incompressible jets. This model more accurately reflects fountain behavior without fully formed wall jets, and adequately predicts ground isobars, upwash dynamic pressure decay, and fountain lift force variation with height above ground
Data from tests of a R4 airfoil in the Langley 0.3-meter transonic cryogenic tunnel
Aerodynamic data for the DFVLR R4 airfoil are presented in both graphic and tabular form. The R4 was tested in the Langley 0.3-Meter Transonic Cryogenic Tunnel (TCT) at Mach number from 0.60 to 0.78 at angles of attack from -2.0 to 8.0 degrees. The airfoil was tested at Reynolds numbers of 4, 6, 10, 15, 30, and 40 million based on the 152.32 mm chord
Mechanical behavior and failure phenomenon of an in situ-toughened silicon nitride
The Weibull modulus, fracture toughness and crack growth resistance of an in-situ toughened, silicon nitride material used to manufacture a turbine combustor were determined from room temperature to 1371 C. The material exhibited an elongated grain structure that resulted in improved fracture toughness, nonlinear crack growth resistance, and good elevated temperature strength. However, low temperature strength was limited by grains of excessive length (30 to 100 microns). These excessively long grains were surrounded by regions rich in sintering additives
1/N_c Expansion of the Heavy Baryon Isgur-Wise Functions
The 1/N_c expansion of the heavy baryon Isgur-Wise functions is discussed.
Because of the contracted SU(2N_f) light quark spin-flavor symmetry, the
universality relations among the Isgur-Wise functions of \Lambda_b to \Lambda_c
and \Sigma_b^{(*)} to \Sigma_c^{(*)} are valid up to the order of 1/N_c^2.Comment: 7 pages, latex, no figures, to appear in Phys. Rev.
Beyond and beneath the hierarchical market economy: global production and working-class conflict in Argentina's automobile industry
This paper argues that the hierarchical market economy (HME) category does not provide an adequate starting point for addressing capitalist diversity in Latin America. Building from a critical perspective on the global commodity chain (GCC) and global production network (GPN) approaches, it instead considers the impact of firms’ transnational relations and the often neglected role of working-class struggles. It will argue that capitalist diversity can only be understood at the nexus of these ostensibly global and local phenomena; and by specifying the strategic decisions taken by firms in Argentina’s automobile industry, it will account for the failure of that sector. Finally, it examines the role of working-class struggles in the industry in Córdoba, Argentina, arguing that these were vital in shaping the specific and unstable form of capitalist diversity in Argentina, as well as potential alternatives to it
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