2,327 research outputs found
Technological research methodology to manage organizational change
Change is a process that is part of the nature of people; however,
within organizations, it should be seen as an invention that will
generate benefits in the markets. The main objective of this work
is to design a technological methodology to manage change from
seven administrative models. For this, a bibliographic review was
carried out; the method applied was analysis-synthesis; the
example technique was used to comment; the support
instruments were a standard data collection form and a
comparative table to analyze this data vertically and
horizontally. The methodology was validated in the research
units of a local university. The main results were 1) The change
of management within organizations is an invention; 2)
administrative models of change are used to manage it; 3)
but, to be successful in managing change, the methodology
of technological research is required in addition to the
administrative process
Metabolic flux from the chloroplast provides signals controlling photosynthetic acclimation to cold in Arabidopsis thaliana
Photosynthesis is especially sensitive to environmental conditions, and the composition of the photosynthetic apparatus can be modulated in response to environmental change, a process termed photosynthetic acclimation. Previously, we identified a role for a cytosolic fumarase, FUM2 in acclimation to low temperature in Arabidopsis thaliana. Mutant lines lacking FUM2 were unable to acclimate their photosynthetic apparatus to cold. Here, using gas exchange measurements and metabolite assays of acclimating and nonâacclimating plants, we show that acclimation to low temperature results in a change in the distribution of photosynthetically fixed carbon to different storage pools during the day. Proteomic analysis of wildâtype Colâ0 Arabidopsis and of a fum2 mutant, which was unable to acclimate to cold, indicates that extensive changes occurring in response to cold are affected in the mutant. Metabolic and proteomic data were used to parameterize metabolic models. Using an approach called flux sampling, we show how the relative export of triose phosphate and 3âphosphoglycerate provides a signal of the chloroplast redox state that could underlie photosynthetic acclimation to cold
Flux sampling is a powerful tool to study metabolism under changing environmental conditions
The development of high-throughput âomic techniques has sparked a rising interest in genome-scale metabolic models, with applications ranging from disease diagnostics to crop adaptation. Efficient and accurate methods are required to analyze large metabolic networks. Flux sampling can be used to explore the feasible flux solutions in metabolic networks by generating probability distributions of steady-state reaction fluxes. Unlike other methods, flux sampling can be used without assuming a particular cellular objective. We have undertaken a rigorous comparison of several sampling algorithms and concluded that the coordinate hit-and-run with rounding (CHRR) algorithm is the most efficient based on both run-time and multiple convergence diagnostics. We demonstrate the power of CHRR by using it to study the metabolic changes that underlie photosynthetic acclimation to cold of Arabidopsis thaliana plant leaves. In combination with experimental measurements, we show how the regulated interplay between diurnal starch and organic acid accumulation defines the plant acclimation process. We confirm fumarate accumulation as a requirement for cold acclimation and further predict Îłâaminobutyric acid to have a key role in metabolic signaling under cold conditions. These results demonstrate how flux sampling can be used to analyze the feasible flux solutions across changing environmental conditions, whereas eliminating the need to make assumptions which introduce observer bias
Spectral Properties of the k-Body Embedded Gaussian Ensembles of Random Matrices
We consider spinless Fermions in degenerate single-particle
levels interacting via a -body random interaction with Gaussian probability
distribution and in the limit to infinity (the embedded -body
random ensembles). We address the cases of orthogonal and unitary symmetry. We
derive a novel eigenvalue expansion for the second moment of the Hilbert-space
matrix elements of these ensembles. Using properties of the expansion and the
supersymmetry technique, we show that for , the average spectrum has
the shape of a semicircle, and the spectral fluctuations are of Wigner-Dyson
type. Using a generalization of the binary correlation approximation, we show
that for , the spectral fluctuations are Poissonian. This is
consistent with the case which can be solved explicitly. We construct
limiting ensembles which are either fully integrable or fully chaotic and show
that the -body random ensembles lie between these two extremes. Combining
all these results we find that the spectral correlations for the embedded
ensembles gradually change from Wigner-Dyson for to Poissonian for .Comment: 44 pages, 3 postscript figures, revised version including a new proof
of one of our main claim
A review of size and geometrical factors influencing resonant frequencies in metamaterials
Although metamaterials and so-called left-handed media have originated from theoretical considerations, it is only by their practical fabrication and the measurement of their properties that they have gained credibility and can fulfil the potential of their predicted properties. In this review we consider some of the more generally applicable fabrication methods and changes in geometry as they have progressed, exhibiting resonant frequencies ranging from radio waves to the visible optical region
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Feasibility study and design concept for an orbiting ice-penetrating radar sounder to characterize in three-dimensions the Europan ice mantle down to (and including) any ice/ocean interface
This report presents a radar sounding model based on the range of current working hypotheses for the nature of Europa's icy shell.Institute for Geophysic
Spectral Properties of the k-Body Embedded Gaussian Ensembles of Random Matrices for Bosons
We consider spinless Bosons distributed over degenerate
single-particle states and interacting through a -body random interaction
with Gaussian probability distribution (the Bosonic embedded -body
ensembles). We address the cases of orthogonal and unitary symmetry in the
limit of infinite matrix dimension, attained either as or as . We derive an eigenvalue expansion for the second moment of the
many-body matrix elements of these ensembles. Using properties of this
expansion, the supersymmetry technique, and the binary correlation method, we
show that in the limit the ensembles have nearly the same
spectral properties as the corresponding Fermionic embedded ensembles. Novel
features specific for Bosons arise in the dense limit defined as
with both and fixed. Here we show that the ensemble is not ergodic, and
that the spectral fluctuations are not of Wigner-Dyson type. We present
numerical results for the dense limit using both ensemble unfolding and
spectral unfolding. These differ strongly, demonstrating the lack of ergodicity
of the ensemble. Spectral unfolding shows a strong tendency towards
picket-fence type spectra. Certain eigenfunctions of individual realizations of
the ensemble display Fock-space localization.Comment: Minor corrections; figure 5 slightly modified (30 pages, 6 figs
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