378 research outputs found
General Personality Disorder: A study into the core components of personality pathology
This thesis explores the structure of various models of General Personality Disorder (PD) and severity levels of PD. In the first part of this thesis, a model of functional impairment, i.e. Livesley's adaptive failure model, as a definition of General PD, and a model of structural impairment, i.e. Kernberg's model of ego- organisation, as a definition of core features of PD, are investigated. The psychometric properties of the General Assessment of Personality Disorders (GAPD), as an instrument for assessing the core features of PD, and the Inventory of Personality Organization (IPO), as a measure of the structural model of Kernberg are described. Also, in a study using item-response theory (IRT), markers of a general level of personality (dys)functioning are identified. These markers and models of general personality dysfunction are compared with the Alternative DSM-5 model for PD. Part two of this thesis explores the relationships between models of general personality dysfunction and models of personality traits. It shows that models of general PD can be distinguished from the Five-Factor Model of personality, and it describes a study towards the incremental value of models of personality dysfunction and models of personality traits in the prediction of the presence and severity of PDs. Finally it presents a brief communication concerning the question whether the extreme endpoints of the Five-Factor Model domains are intrinsically maladaptive. The results of the study are discussed in the context of the proposed changes of the definition of PD for the DSM-5, and clinical applications are formulated
Identifying the optimal use of CTCs in the early staging phase of breast cancer
Objectives: Circulating tumour cells (CTCs) in the blood can give important information about the prognosis and treatment options for cancer patients. Methods like cell-search are not sensitive enough because the blood samples are small (7,5 mL). Currently a technique is developed which can separate CTCs from the whole blood and is called the CTC Trap. This study addresses the potential impact of implementing the CTC Trap in addition to currently used imaging techniques in early staging of primary stage I-III breast cancer in women. Methods: The early staging process has been identified using the Dutch breast cancer guideline. This process is displayed in a decision tree. Three points in this process have been identified as possible implementation options for the CTC Trap. A simulation model has been built in Excel to simulate the cost-effectiveness of implementing the CTC Trap at these three different points. Results: Potentially relevant points for the CTC trap are: 1) following negative sentinel lymph node procedure to test for micro metastases, 2) following negative result of initial MRI to test for (micro-) metastases, 3) following negative results of further imaging. Usual care resulted in an average survival of 2,42 years, a 3-year survival of 93,71%, 1,51 QALYs and a cost of € 992,56. When implemented at all 3 implementation points simultaneously CTC Trap resulted in an average survival of 2,84 years, a 3-year survival of 97,46 %, 1,84 QALYS and a total cost of € 6.035,45. Conclusions: CTCs clearly have the potential to improve overall survival. Use of CTCs can potentially improve survival with 0,42 years and improve QALYs with 0,34. Costs do increase at all options but from a health economic perspective it is most valuable to implement CTC Trap in option 1) following negative sentinel lymph node procedure to test for (micro-) metastases
Mechanism of thermally activated c-axis dissipation in layered High-T superconductors at high fields
We propose a simple model which explains experimental behavior of -axis
resistivity in layered High-T superconductors at high fields in a limited
temperature range. It is generally accepted that the in-plane dissipation at
low temperatures is caused by small concentration of mobile pancake vortices
whose diffusive motion is thermally activated. We demonstrate that in such
situation a finite conductivity appears also in -direction due to the phase
slips between the planes caused by the mobile pancakes. The model gives
universal relation between the components of conductivity which is in good
agreement with experimental data.Comment: RevTeX, 4 pages, 2 Postscript figure
Full Bulk Spin Polarization and Intrinsic Tunnel Barriers at the Surface of Layered Manganites
Transmission of information using the spin of the electron as well as its
charge requires a high degree of spin polarization at surfaces. At surfaces
however this degree of polarization can be quenched by competing interactions.
Using a combination of surface sensitive x-ray and tunneling probes, we show
for the quasi-two-dimensional bilayer manganites that the outermost Mn-O
bilayer, alone, is affected: it is a 1-nm thick insulator that exhibits no
long-range ferromagnetic order while the next bilayer displays the full spin
polarization of the bulk. Such an abrupt localization of the surface effects is
due to the two-dimensional nature of the layered manganite while the loss of
ferromagnetism is attributed to weakened double exchange in the reconstructed
surface bilayer and a resultant antiferromagnetic phase. The creation of a
well-defined surface insulator demonstrates the ability to naturally
self-assemble two of the most demanding components of an ideal magnetic tunnel
junction.Comment: 19 pages, 5 figure
Excellent passivation of germanium surfaces by POx/Al2O3 stacks
Passivation of germanium surfaces is vital for the application of germanium in next-generation electronic and photonic devices. In this work, it is demonstrated that stacks of phosphorous oxide and aluminum oxide (POx/Al2O3) provide excellent and stable passivation of germanium surfaces, with state-of-the-art surface recombination velocities down to 8.9 cm/s. The POx/Al2O3 stack also exhibits positive fixed charge on germanium, which makes it especially suited for passivation of highly doped n-type germanium surfaces. The chemical passivation mechanism is found to be related to the passivation of defects by hydrogen, which is mobilized by the formation of AlPO4 upon annealing. Furthermore, the GeOx interlayer is removed due to a kind of “self-cleaning” process during the deposition of POx/Al2O3 stacks on germanium, which may in part explain the excellent passivation quality. This self-cleaning of the interface may also allow simplified device fabrication workflows, as pretreatments may be omitted
Vortices in a Thin Film Superconductor with a Spherical Geometry
We report results from Monte Carlo simulations of a thin film superconductor
in a spherical geometry within the lowest Landau level approximation. We
observe the absence of a phase transition to a low temperature vortex solid
phase with these boundary conditions; the system remains in the vortex liquid
phase for all accessible temperatures. The correlation lengths are measured for
phase coherence and density modulation. Both lengths display identical
temperature dependences, with an asymptotic scaling form consistent with a
continuous zero temperature transition. This contrasts with the first order
freezing transition which is seen in the alternative quasi-periodic boundary
conditions. The high temperature perturbation theory and the ground states of
the spherical system suggest that the thermodynamic limit of the spherical
geometry is the same as that on the flat plane. We discuss the advantages and
drawbacks of simulations with different geometries, and compare with current
experimental conclusions. The effect of having a large scale inhomogeneity in
the applied field is also considered.Comment: This replacment contains substantial revisions: the new article is
twice as long with new and different results on the thermodynamic limit on
the sphere plus a full discussion on the alternative boundary conditions used
in simulations in the LLL approximation. 19 pages, 12 encapsulated PostScript
figures, 1 JPEG figure, uses RevTeX (with epsf
Absence of the Transition into Abrikosov Vortex State of Two-Dimensional Type-II Superconductor with Weak Pinning
The resistive properties of thin amorphous NbO_{x} films with weak pinning
were investigated experimentally above and below the second critical field
H_{c2}. As opposed to bulk type II superconductors with weak pinning where a
sharp change of resistive properties at the transition into the Abrikosov state
is observed at H_{c4}, some percent below H_{c2} (V.A.Marchenko and
A.V.Nikulov, 1981), no qualitative change of resistive properties is observed
down to a very low magnetic field, H_{c4} < 0.006 H_{c2}, in thin films with
weak pinning. The smooth dependencies of the resistivity observed in these
films can be described by paraconductivity theory both above and below H_{c2}.
This means that the fluctuation superconducting state without phase coherence
remains appreciably below H_{c2} in the two-dimensional superconductor with
weak pinning. The difference the H_{c4}/H_{c2} values, i.e. position of the
transition into the Abrikosov state, in three- and two-dimensional
superconductors conforms to the Maki-Takayama result 1971 year according to
which the Abrikosov solution 1957 year is valid only for a superconductor with
finite dimensions. Because of the fluctuation this solution obtained in the
mean field approximation is not valid in a relatively narrow region below
H_{c2} for bulk superconductors with real dimensions and much below H_{c2} for
thin films with real dimensions. The superconducting state without phase
coherence should not be identified with the mythical vortex liquid because the
vortex, as a singularity in superconducting state with phase coherence, can not
exist without phase coherence.Comment: 4 pages, 4 figure
- …