1,957 research outputs found
Successful implementation of self-managing teams
Purpose: Following health-care organisations, many mental health-care organisations nowadays consider starting to work with self-managing teams as their organisation structure. Although the concept could be effective, the way of implementing self-managing teams in an organisation is crucial to achieve sustainable results. Therefore, this paper aims to examine how working with self-managing teams can be implemented successfully in the mental health-care sector where various factors for the successful implementation are distinguished. Design/methodology/approach: This qualitative case study is executed by analysing 18 interviews within two self-managing teams in a mental health-care organisation located in the Netherlands. A coding process is executed in two steps. The first step is open coding, to make small summarising notes within each interview section. The second step is refocused coding, where the open codes were collected, categorised and summarised by searching for recurrence and significance. The coding process is made visible within a code tree. This code tree formed the basis for writing the findings. Findings: Success factors for the implementation of a self-managing team that resulted from this research are a clear task portfolio division, good relationships within the team and a coaching trajectory with attention for a possible negative past. Originality/value: By having used a specific change management model, the Change Competence Model, it can be concluded that a high change capacity will positively influence the success of a self-managing team in the context of a mental health-care organisation
Local Isoelectronic Reactivity of Solid Surfaces
The quantity w^N(r) = ( 1/ k^2 T_el)[partial n(r, T_el) / partial
T_el]_(v(r),N) is introduced as a convenient measure of the local isoelectronic
reactivity of surfaces. It characterizes the local polarizability of the
surface and it can be calculated easily. The quantity w^N(r) supplements the
charge transfer reactivity measured e.g. by the local softness to which it is
closely related. We demonstrate the applicability and virtues of the function
w^N(r) for the example of hydrogen dissociation and adsorption on Pd(100).Comment: RevTeX, 13 pages, 3 figures, to appear in Phys. Rev. Let
Superconducting and Normal State Properties of Neutron Irradiated MgB2
We have performed a systematic study of the evolution of the superconducting
and normal state properties of neutron irradiated MgB wire segments as a
function of fluence and post exposure annealing temperature and time. All
fluences used suppressed the transition temperature, Tc, below 5 K and expanded
the unit cell. For each annealing temperature Tc recovers with annealing time
and the upper critical field, Hc2(T=0), approximately scales with Tc. By
judicious choice of fluence, annealing temperature and time, the Tc of damaged
MgB2 can be tuned to virtually any value between 5 and 39 K. For higher
annealing temperatures and longer annealing times the recovery of Tc tends to
coincide with a decrease in the normal state resistivity and a systematic
recovery of the lattice parameters.Comment: Updated version, to appear in Phys. Rev.
Does the Red Queen reign in the kingdom of digital organisms?
In competition experiments between two RNA viruses of equal or almost equal
fitness, often both strains gain in fitness before one eventually excludes the
other. This observation has been linked to the Red Queen effect, which
describes a situation in which organisms have to constantly adapt just to keep
their status quo. I carried out experiments with digital organisms
(self-replicating computer programs) in order to clarify how the competing
strains' location in fitness space influences the Red-Queen effect. I found
that gains in fitness during competition were prevalent for organisms that were
taken from the base of a fitness peak, but absent or rare for organisms that
were taken from the top of a peak or from a considerable distance away from the
nearest peak. In the latter two cases, either neutral drift and loss of the
fittest mutants or the waiting time to the first beneficial mutation were more
important factors. Moreover, I found that the Red-Queen dynamic in general led
to faster exclusion than the other two mechanisms.Comment: 10 pages, 5 eps figure
Complex Spatial Dynamics of Oncolytic Viruses In Vitro: Mathematical and Experimental Approaches
Oncolytic viruses replicate selectively in tumor cells and can serve as targeted treatment agents. While promising results have been observed in clinical trials, consistent success of therapy remains elusive. The dynamics of virus spread through tumor cell populations has been studied both experimentally and computationally. However, a basic understanding of the principles underlying virus spread in spatially structured target cell populations has yet to be obtained. This paper studies such dynamics, using a newly constructed recombinant adenovirus type-5 (Ad5) that expresses enhanced jellyfish green fluorescent protein (EGFP), AdEGFPuci, and grows on human 293 embryonic kidney epithelial cells, allowing us to track cell numbers and spatial patterns over time. The cells are arranged in a two-dimensional setting and allow virus spread to occur only to target cells within the local neighborhood. Despite the simplicity of the setup, complex dynamics are observed. Experiments gave rise to three spatial patterns that we call “hollow ring structure”, “filled ring structure”, and “disperse pattern”. An agent-based, stochastic computational model is used to simulate and interpret the experiments. The model can reproduce the experimentally observed patterns, and identifies key parameters that determine which pattern of virus growth arises. The model is further used to study the long-term outcome of the dynamics for the different growth patterns, and to investigate conditions under which the virus population eliminates the target cells. We find that both the filled ring structure and disperse pattern of initial expansion are indicative of treatment failure, where target cells persist in the long run. The hollow ring structure is associated with either target cell extinction or low-level persistence, both of which can be viewed as treatment success. Interestingly, it is found that equilibrium properties of ordinary differential equations describing the dynamics in local neighborhoods in the agent-based model can predict the outcome of the spatial virus-cell dynamics, which has important practical implications. This analysis provides a first step towards understanding spatial oncolytic virus dynamics, upon which more detailed investigations and further complexity can be built
Injection Kinetics and Electronic Structure at the N719 TiO2 Interface Studied by Means of Ultrafast XUV Photoemission Spectroscopy
The method of transient XUV photoemission spectroscopy is developed to investigate the ultrafast dynamics of heterogeneous electron transfer at the interface between the N719 ruthenium dye complex and TiO2 nanoparticles. XUV light from high order harmonic generation is used to probe the electron density distribution among the ground and excited states at the interface after its exposure to a pump laser pulse of 530 nm wavelength. A spectral decomposition of the transient emission signal is used to follow the population and decay dynamics of the involved transient states individually. By comparing results obtained for the N719 TiO2 and N719 FTO interfaces, we can unambiguously reveal the kinetics of electrons injected to TiO2 from the singlet metal to ligand charge transfer MLCT excited state of the dye. With the developed approach, we characterize both the kinetic constants and the absolute binding energies of the singlet and triplet MLCT states of the dye and the state of electrons injected to the conduction band of TiO2. The energy levels of the singlet and triplet states are found to lie 0.7 eV above and 0.2 eV below the conduction band minimum, respectively. This energetic structure gives rise to a strong driving force for injection from the singlet state and a slow electron transfer from the triplet state, the latter being possible due to a partial overlap of the triplet state band of N719 and the conduction band of TiO
High pressure evolution of FeO electronic structure revealed by X-ray absorption
We report the first high pressure measurement of the Fe K-edge in hematite
(FeO) by X-ray absorption spectroscopy in partial fluorescence yield
geometry. The pressure-induced evolution of the electronic structure as
FeO transforms from a high-spin insulator to a low-spin metal is
reflected in the x-ray absorption pre-edge. The crystal field splitting energy
was found to increase monotonically with pressure up to 48 GPa, above which a
series of phase transitions occur. Atomic multiplet, cluster diagonalization,
and density-functional calculations were performed to simulate the pre-edge
absorption spectra, showing good qualitative agreement with the measurements.
The mechanism for the pressure-induced phase transitions of FeO is
discussed and it is shown that ligand hybridization significantly reduces the
critical high-spin/low-spin pressure.Comment: 5 pages, 4 figures and 1 tabl
High-resolution x-ray telescopes
High-energy astrophysics is a relatively young scientific field, made
possible by space-borne telescopes. During the half-century history of x-ray
astronomy, the sensitivity of focusing x-ray telescopes-through finer angular
resolution and increased effective area-has improved by a factor of a 100
million. This technological advance has enabled numerous exciting discoveries
and increasingly detailed study of the high-energy universe-including accreting
(stellar-mass and super-massive) black holes, accreting and isolated neutron
stars, pulsar-wind nebulae, shocked plasma in supernova remnants, and hot
thermal plasma in clusters of galaxies. As the largest structures in the
universe, galaxy clusters constitute a unique laboratory for measuring the
gravitational effects of dark matter and of dark energy. Here, we review the
history of high-resolution x-ray telescopes and highlight some of the
scientific results enabled by these telescopes. Next, we describe the planned
next-generation x-ray-astronomy facility-the International X-ray Observatory
(IXO). We conclude with an overview of a concept for the next next-generation
facility-Generation X. The scientific objectives of such a mission will require
very large areas (about 10000 m2) of highly-nested lightweight
grazing-incidence mirrors with exceptional (about 0.1-arcsecond) angular
resolution. Achieving this angular resolution with lightweight mirrors will
likely require on-orbit adjustment of alignment and figure.Comment: 19 pages, 11 figures, SPIE Conference 7803 "Adaptive X-ray Optics",
part of SPIE Optics+Photonics 2010, San Diego CA, 2010 August 2-
Anisotropic magnetoresistance in a 2DEG in a quasi-random magnetic field
We present magnetotransport results for a 2D electron gas (2DEG) subject to
the quasi-random magnetic field produced by randomly positioned sub-micron Co
dots deposited onto the surface of a GaAs/AlGaAs heterostructure. We observe
strong local and non-local anisotropic magnetoresistance for external magnetic
fields in the plane of the 2DEG. Monte-Carlo calculations confirm that this is
due to the changing topology of the quasi-random magnetic field in which
electrons are guided predominantly along contours of zero magnetic field.Comment: 4 pages, 6 figures, submitted to Phys. Rev.
Asexual and sexual replication in sporulating organisms
This paper develops models describing asexual and sexual replication in
sporulating organisms. Replication via sporulation is the replication strategy
for all multicellular life, and may even be observed in unicellular life (such
as with budding yeast). We consider diploid populations replicating via one of
two possible sporulation mechanisms: (1) Asexual sporulation, whereby adult
organisms produce single-celled diploid spores that grow into adults
themselves. (2) Sexual sporulation, whereby adult organisms produce
single-celled diploid spores that divide into haploid gametes. The haploid
gametes enter a haploid "pool", where they may recombine with other haploids to
form a diploid spore that then grows into an adult. We consider a haploid
fusion rate given by second-order reaction kinetics. We work with a simplified
model where the diploid genome consists of only two chromosomes, each of which
may be rendered defective with a single point mutation of the wild-type. We
find that the asexual strategy is favored when the rate of spore production is
high compared to the characteristic growth rate from a spore to a reproducing
adult. Conversely, the sexual strategy is favored when the rate of spore
production is low compared to the characteristic growth rate from a spore to a
reproducing adult. As the characteristic growth time increases, or as the
population density increases, the critical ratio of spore production rate to
organism growth rate at which the asexual strategy overtakes the sexual one is
pushed to higher values. Therefore, the results of this model suggest that, for
complex multicellular organisms, sexual replication is favored at high
population densities, and low growth and sporulation rates.Comment: 8 pages, 5 figures, to be submitted to Journal of Theoretical
Biology, figures not included in this submissio
- …