6,505 research outputs found
An Integral Perspective on Depression
The integral approach to therapy proposes to accommodate all the etiological factors of
unipolar depression in its theory, as well as to make use of all existing therapies, both pharmacological
and psychological, in the treatment of unipolar depression. Integral Therapy is
compared to cognitive therapy to find evidence for its superiority over the cognitive
approach. It appears that the cognitive therapy is more cost-effective than Integral Therapy
as an individual approach in the treatment of depression, but that the integral perspective
accounts better for etiological factors
Viscous shocks in Hele-Shaw flow and Stokes phenomena of the Painleve I transcendent
In Hele-Shaw flows at vanishing surface tension, the boundary of a viscous
fluid develops cusp-like singularities. In recent papers [1, 2] we have showed
that singularities trigger viscous shocks propagating through the viscous
fluid. Here we show that the weak solution of the Hele-Shaw problem describing
viscous shocks is equivalent to a semiclassical approximation of a special real
solution of the Painleve I equation. We argue that the Painleve I equation
provides an integrable deformation of the Hele-Shaw problem which describes
flow passing through singularities. In this interpretation shocks appear as
Stokes level-lines of the Painleve linear problem.Comment: A more detailed derivation is include
The Application of the Econometric Models with Qualitative Variables in the Analysis of the Non Academic Behaviors at the Level of the Romanian Higher Education System
The purpose of this paper was to apply the econometric models with qualitative variables in order to analyze two non academic behaviors at the level of the Romanian higher education system: cheating on the exams by copying or by direct or intermediary intervention at the professor.Logit Model, survey, sample, fraud
Unstable fingering patterns of Hele-Shaw flows as a dispersionless limit of the KdV hierarchy
We show that unstable fingering patterns of two dimensional flows of viscous
fluids with open boundary are described by a dispersionless limit of the KdV
hierarchy. In this framework, the fingering instability is linked to a known
instability leading to regularized shock solutions for nonlinear waves, in
dispersive media. The integrable structure of the flow suggests a dispersive
regularization of the finite-time singularities.Comment: Published versio
Impact of an external electron acceptor on phosphorus mobility between water and sediments
The present work assessed the impact of an external electron acceptor on phosphorus fluxes between water-sediment interface. Microcosm experiments simulating a sediment microbial fuel cell (SMFC) were carried out and phosphorus was extracted by an optimized combination of three methods. Despite the low voltage recorded, ∼96 mV (SMFC with carbon paper anode) and ∼146 mV (SMFC with stainless steel scourer anode), corresponding to a power density of 1.15 mW/m2 and 0.13 mW/m2, it was enough to produce an increase in the amounts of metal bound phosphorus (14% vs 11%), Ca-bound phosphorus (26% vs 23%) and refractory phosphorus (33% vs 28%). These results indicate an important role of electroactive bacteria in the phosphorus cycling and open a new perspective for preventing metal bound phosphorus dissolution from sediments.The authors are indebted and grateful to the Regional Department of Water Resources and Land Planning (Azores) and its staff. The authors also acknowledge the Grant SFRH/BPD/8052812011 from the Foundation for Science and Technology, Portugal, awarded to Gilberto Martins
Modelling and simulation of VSC-HVDC connection for offshore wind power plants
Several large offshore wind power plants (WPP)
are planned in the seas around Europe. VSC-HVDC is a suitable
means of integrating such large and distant offshore WPP which
need long submarine cable transmission to the onshore grid.
Recent trend is to use large wind turbine generators with full
scale converters to achieve an optimal operation over a wide
speed range. The offshore grid then becomes very much different
from the conventional power system grid, in the sense that it is
connected to power electronic converters only. A model of the
wind power plant with VSC-HVDC connection is developed in
PSCAD for time-domain dynamic simulation. This paper
presents the modelling and simulation of such a system. A single
line to ground fault has been simulated and fault currents for the
grounded and ungrounded offshore grid system is obtained
through simulation and then compared.Postprint (published version
Medium voltage three-level converters for the grid connection of a multi-MW wind turbine
Three-level (3L) neutral point clamped (NPC), flying capacitor (FC), and H-bridge (HB) voltage
source converters (VSCs) as a grid-side full-scale medium voltage (MV) converter are modeled,
controlled, and simulated for the grid connection of a hypothetical 6MW wind turbine. Via the
converter topological features and the simulation results demonstrating the converter performance,
these three 3L-VSCs are discussed and compared in terms of power density and reliability, which can
be considered as two of the most important criteria for the converters placed in wind turbine nacelles.
Given the grid connection circuit (without capacitive switching ripple filters), the 3L-HB-VSC is
expected to be superior with respect to power density and reliability over the 3L-NPC- and -FC-VSCs.Peer ReviewedPostprint (published version
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