8,620 research outputs found
Repeat Buying Behavior for Ornamental Plants: A Consumer Profile
The main objective of this research was to study what stimulates repeat buying behavior for ornamental plants by segmenting consumer demographics and other important variables in the purchasing decision for ornamental plants. Specifically, we looked at the number of transactions per month as a function of the purpose of the purchase. Consumer’s behavioral and socio-demographic characteristics that are more likely to influence the number of ornamental transactions were also identified.Green Industry, flower demand, consumer preferences, Consumer/Household Economics, Marketing, M31, R22,
A Nonequilibrium Finite-Rate Carbon Ablation Model for Radiating Earth Re-entry Flows
Vehicles entering planetary atmospheres at high speed require an ablative heat shield in order to withstand the high thermal energy flux to the body. The interaction between the ablative products and the flow field is not well characterized. Numerical simulations were conducted to investigate the influence of carbon ablation on shock layer radiation. Data collected from experiments performed in the X-2 expansion tunnel at the University of Queensland was used to compare to the simulations. The model was a short half-cylinder made of isomolded graphite and was tested in 8.6 km/s Earth entry flow. The model surface was heated within a temperature range of 1770-3280 K. The radiation emitted from the CN violet bands was measured by ultraviolet spectrometry in a spectral range from 353-391 nm. This research develops a novel finite-rate surface kinetic model for determining the chemical state of an ablating boundary layer. The proposed ablation model accounts for competing surface reaction processes such as adsorption/desorption, Eley-Rideal mechanisms, oxidation, nitridation, and sublimation. The included oxidation mechanisms predict CO as the primary oxidized product at the considered surface temperatures, which is in agreement with experiment and theory. A previous model had incorrectly predicted CO2 as the primary oxidized product for a majority of the tested surface temperatures. The ablative gas species predicted by this new surface model results in better agreement with experimental spectral measurements than predictions provided by legacy ablation models, and represents a significant improvement in current modeling capabilities for hypersonic nonequilibrium ablating re-entry flows
Discrete breathers for understanding reconstructive mineral processes at low temperatures
Reconstructive transformations in layered silicates need a high tem- perature
in order to be observed. However, very recently, some systems have been found
where transformation can be studied at temperatures 600 C below the lowest
experimental results previously reported, including sol-gel methods. We explore
the possible relation with the existence of intrinsic localized modes, known as
discrete breathers. We construct a model for nonlinear vibrations within the
cation layer, obtain their parameters and calculate them numerically, obtaining
their energies. Their statistics shows that although there are far less
breathers than phonons, there are much more above the activation energy, being
therefore a good candidate to explain the reconstructive transformations at low
temperature.Comment: 27 pages, 11 figure
Binary Search Algorithm for Mixed Integer Optimization: Application to energy management in a microgrid
This paper presents a binary search algorithm
to deal with binary variables in mixed integer optimization
problems. One example of this kind of problem is the optimal
operation of hydrogen storage and energy sale and purchase
into a microgrids context. In this work was studied a system
composed by a microgrid that has a connection with the
external electrical network and a charging station for electric
cars. The system modeling was carried out by the Energy
Hubs methodology. The proposed algorithm transforms the
MIQP (Mixed Integer Quadratic Program) problem into a QP
(Quadratic Program) that is easier to solve. In this way the
overall control task is carried out the electricity purchase and
sale to the power grid, maximizes the use of renewable energy
sources, manages the use of energy storages and supplies the
charge of the parked vehicles.Ministerio de EconomĂa y Competitividad DPI2013-46912-C2-1-RUniversidad de Sevilla CNPq401126/2014-5Universidad de Sevilla CNPq303702/2011-
IGFBP-3 inhibits Wnt signaling in metastatic melanoma cells.
In previous works, we have shown that insulin-like growth factor-binding protein-3 (IGFBP-3), a tissue and circulating protein able to bind to IGFs, decreases drastically in the blood serum of patients with diffuse metastatic melanoma. In agreement with the clinical data, recombinant IGFBP-3 was found to inhibit the motility and invasiveness of cultured metastatic melanoma cells and to prevent growth of grafted melanomas in mice. The present work was aimed at identifying the signal transduction pathways underlying the anti-tumoral effects of IGFBP-3. We show that the anti-tumoral effect of IGFBP-3 is due to inhibition of the Wnt pathway and depends upon the presence of CD44, a receptor protein known to modulate Wnt signaling. Once it has entered the cell, IGFBP-3 binds the Wnt signalosome interacting specifically with its component GSK-3β. As a consequence, the β-catenin destruction complex dissociates from the LRP6 Wnt receptor and GSK-3β is activated through dephosphorylation, becoming free to target cytoplasmic β-catenin which is degraded by the proteasomal pathway. Altogether, the results suggest that IGFBP-3 is a novel and effective inhibitor of Wnt signaling. As IGFBP-3 is a physiological protein which has no detectable toxic effects either on cultured cells or live mice, it might qualify as an interesting new therapeutic agent in melanoma, and potentially many other cancers with a hyperactive Wnt signaling
The Chrono-geometrical Structure of Special and General Relativity: a Re-Visitation of Canonical Geometrodynamics
A modern re-visitation of the consequences of the lack of an intrinsic notion
of instantaneous 3-space in relativistic theories leads to a reformulation of
their kinematical basis emphasizing the role of non-inertial frames centered on
an arbitrary accelerated observer. In special relativity the exigence of
predictability implies the adoption of the 3+1 point of view, which leads to a
well posed initial value problem for field equations in a framework where the
change of the convention of synchronization of distant clocks is realized by
means of a gauge transformation. This point of view is also at the heart of the
canonical approach to metric and tetrad gravity in globally hyperbolic
asymptotically flat space-times, where the use of Shanmugadhasan canonical
transformations allows the separation of the physical degrees of freedom of the
gravitational field (the tidal effects) from the arbitrary gauge variables.
Since a global vision of the equivalence principle implies that only global
non-inertial frames can exist in general relativity, the gauge variables are
naturally interpreted as generalized relativistic inertial effects, which have
to be fixed to get a deterministic evolution in a given non-inertial frame. As
a consequence, in each Einstein's space-time in this class the whole
chrono-geometrical structure, including also the clock synchronization
convention, is dynamically determined and a new approach to the Hole Argument
leads to the conclusion that "gravitational field" and "space-time" are two
faces of the same entity. This view allows to get a classical scenario for the
unification of the four interactions in a scheme suited to the description of
the solar system or our galaxy with a deperametrization to special relativity
and the subsequent possibility to take the non-relativistic limit.Comment: 33 pages, Lectures given at the 42nd Karpacz Winter School of
Theoretical Physics, "Current Mathematical Topics in Gravitation and
Cosmology", Ladek, Poland, 6-11 February 200
Interfunctional coordination: the role of digitalization
Purpose:
This research investigates interfunctional coordination (IC) in a B-to-B context. More specifically, it explores the role of digitalization as a strategic driver for an effective IC.
Design/methodology/approach:
Following a qualitative methodology, three studies have been integrated: Study 1 (focus group with five participants); Study 2 (31 in-depth interviews with top executives); Study 3 (online focus group with 9 experts).
Findings:
One finding is that digitalization is the main driver for IC and can be considered strategic. Other findings show that digitalization can enhance IC, but it was also found that digitalization can have negative side effects on IC.
Originality/value:
This study contributes to the understanding of the importance of digitalization on IC and also contributes to the conceptualization of IC as a dynamic capability
- …