817 research outputs found
Developing Heuristic-Based Quality Judgements: Attention Blocking in Consumer Choice
Through a series of experiments we illustrate how the sequential order in which consumers receive information can influence the way this information is processed and affect consumers’ decisions. Specifically, when participants initially receive information regarding brand/quality or price/quality associations, these associations can block consumers’ attention to more relevant quality-determining physical attributes. Moreover, this process of attention blocking can carry-over to affect quality judgements pertaining to similarly branded or priced products beyond the product in which blocking was initiated. This implies that consumers judgements of quality may be heavily dependent on “first impressions” which develop into brand and price heuristics.Consumer Behavior; Consumer Learning; Marketing Strategy
Exploring the space between: Social networks, trust, and urban school district leaders
Una serie de académicos han estudiado el contexto del distrito en el que se encuentran inmersos los centros educativos. Estos estudios sugieren la importancia de las oficinas municipales como apoyo o limitación del trabajo de los centros educativos ofreciendo estrategias para construir las relaciones entre los distritos y los líderes locales. Esta es una tarea importante y, sin embargo, frecuentemente se pasa por alto que las mejoras de los esfuerzos organizativos se construyen socialmente. Por ello, el análisis de las redes sociales y la confianza entre los líderes del distrito y de los centros educativos puede proporcionar una visión desde dentro respecto a los apoyos y limitaciones relacionados con la mejora. En este estudio de caso se utiliza una red social y datos sobre la confianza para explorar las mejores prácticas relacionadas con los líderes, en un distrito escolar de tamaño medio con bajo rendimiento. Los resultados sugieren unos lazos sociales de la red débiles, bajos niveles de confianza y una previsible relación entre la confianza y los intercambios recíprocos con las mejores prácticas relacionadas con la mejoraA number of scholars are exploring the district context in which schools are embedded. These studies suggest the importance of the district office as a support or constraint to the work of schools and offer strategies for building relations between district and site leaders. While this is an important task, what is frequently overlooked is that organizational improvement efforts are often socially constructed. Therefore, an analysis of social networks and trust between district and site leaders may provide additional insights into supports and constraints related to improvement. This case study uses social network and trust data to explore the underlying best practice relations between leaders in a midsize underperforming urban school district. Results suggest weak network ties, low levels of trust, and a predictive relationship between trust and the reciprocal exchange of best practices related to improvementEsta investigación ha sido apoyada por una financiación de la W.T. Grant Foundation (Grant, nº 10174
Modeling canopy-induced turbulence in the Earth system: a unified parameterization of turbulent exchange within plant canopies and the roughness sublayer (CLM-ml v0)
Land surface models used in climate models neglect the roughness sublayer and parameterize within-canopy turbulence in an ad hoc manner. We implemented a roughness sublayer turbulence parameterization in a multilayer canopy model (CLM-ml v0) to test if this theory provides a tractable parameterization extending from the ground through the canopy and the roughness sublayer. We compared the canopy model with the Community Land Model (CLM4.5) at seven forest, two grassland, and three cropland AmeriFlux sites over a range of canopy heights, leaf area indexes, and climates. CLM4.5 has pronounced biases during summer months at forest sites in midday latent heat flux, sensible heat flux, gross primary production, nighttime friction velocity, and the radiative temperature diurnal range. The new canopy model reduces these biases by introducing new physics. Advances in modeling stomatal conductance and canopy physiology beyond what is in CLM4.5 substantially improve model performance at the forest sites. The signature of the roughness sublayer is most evident in nighttime friction velocity and the diurnal cycle of radiative temperature, but is also seen in sensible heat flux. Within-canopy temperature profiles are markedly different compared with profiles obtained using Monin–Obukhov similarity theory, and the roughness sublayer produces cooler daytime and warmer nighttime temperatures. The herbaceous sites also show model improvements, but the improvements are related less systematically to the roughness sublayer parameterization in these canopies. The multilayer canopy with the roughness sublayer turbulence improves simulations compared with CLM4.5 while also advancing the theoretical basis for surface flux parameterizations
Bed-load effects on hydrodynamics of rough-bed open-channel flows
Peer reviewedPublisher PD
Experiments on the flow over a hill covered by a canopy in stably stratified conditions
It has long been suspected that thermo-topographic flows, especially gravity currents, within vegetation canopies on complex terrain are one of the main reasons behind the failure to reconcile micrometeorological and biometric estimates of canopy-atmosphere exchange at many sites. However, the physical mechanisms governing the initiation and the scaling of these flows remain poorly understood. Here we present the results of a novel wind tunnel study that looks in detail at the flow within and above an open canopy in stably stratified conditions and investigates the physical mechanisms responsible for gravity currents within canopies. The wind tunnel simulations demonstrate that gravity currents are established through a complex balance of competing forces on the flow within the canopy. Three forcing terms act on the flow in the canopy as it passes over the hill. First is the hydrodynamic pressure gradient associated with the boundary layer flow aloft; second, a hydrostatic pressure gradient associated with the displacement of temperature and density surfaces by the hill, and finally a thermal wind term, where a streamwise pressure gradient is caused by changes in the depth of the temperature perturbations to the flow. The net balance of these forces is opposed by the canopy drag. Gravity currents, however, do not appear unless the turbulence, which supports the transport of momentum into the canopy, is also reduced. This suppression occurs preferentially deep within the canopy due to a Richardson number cut-off effect, which is directly linked to the different transport mechanisms of heat and momentum across the boundary layers on the canopy elements. The gravity current first appears at the ground surface, despite cooling profiles that are concentrated in the upper canopy. Once initiated, a gravity current can propagate substantial distances away from the triggering topography, driven by the thermal wind term. If shown to be robust these results have widespread implications for the micrometeorology, atmospheric boundary layer and numerical weather prediction communities
Trichinella nativa in a black bear from Plymouth, New Hampshire
A suspected case of trichinellosis was identified in a single patient by the New Hampshire Public Health Laboratories in Concord, NH. The patient was thought to have become infected by consumption of muscle larvae (ML) in undercooked meat from a black bear killed in Plymouth, NH in October 2003 and stored frozen at 20 8C fro 4 months. In January 2004, a 600 g sample of the meat was thawed at 4 8C, digested in hydrochloric acid and pepsin, and larvae were collected by sedimentation. Intact, coiled, and motile ML were recovered (366 larvae per gram (lpg) of tissue), which were passed into mice and pigs. Multiplex PCR revealed a single 127 bp amplicon, indicative of Trichinella nativa. The Reproductive Capacity Index (RCI) for the T. nativa-Plymouth isolate in mice was 24.3. Worm burdens in the diaphragms of two 3-month-old pigs given 2500 ML were 0.05 and 0.2 lpg by 35 days post-inoculation, while 2.2 and 0.75 lpg were recovered from two 3-month-old pigs given 10,000 ML; no larvae were recovered from four 1-year-old pigs given 2500 ML (n = 2) or 10,000 ML (n = 2). Viable larvae were also recovered from frozen black bear meat harvested at two additional locations, one in southern Ontario, Canada, and one in upstate New York, USA. Multiplex PCR using genomic DNA from these parasite samples demonstrated that both isolates were T. nativa. This is the first report of the freeze-resistant species, T. nativa, within the continental United States
Engineering a Seven Enzyme Biotransformation using Mathematical Modelling and Characterized Enzyme Parts (article)
This is the final version. Available on open access from Wiley via the DOI in this recordThe dataset associated with this article is located in ORE at: https://doi.org/10.24378/exe.1623Multi‐step enzyme reactions offer considerable cost and productivity benefits. Process models offer a route to understanding the complexity of these reactions, and allow for their optimization. Despite the increasing prevalence of multi‐step biotransformations, there are few examples of process models for enzyme reactions. From a toolbox of characterized enzyme parts, we demonstrate the construction of a process model for a seven enzyme, three step biotransformation using isolated enzymes. Enzymes for cofactor regeneration were employed to make this in vitro reaction economical. Good modelling practice was critical in evaluating the impact of approximations and experimental error. We show that the use and validation of process models was instrumental in realizing and removing process bottlenecks, identifying divergent behavior, and for the optimization of the entire reaction using a genetic algorithm. We validated the optimized reaction to demonstrate that complex multi‐step reactions with cofactor recycling involving at least seven enzymes can be reliably modelled and optimized.Biotechnology & Biological Sciences Research Council (BBSRC)GlaxoSmithKlin
Subdivision surfaces with creases and truncated multiple knot lines
We deal with subdivision schemes based on arbitrary degree B-splines. We focus on extraordinary knots which exhibit various levels of complexity in terms of both valency and multiplicity of knot lines emanating from such knots. The purpose of truncated multiple knot lines is to model creases which fair out. Our construction supports any degree and any knot line multiplicity and provides a modelling framework familiar to users used to B-splines and NURBS systems
Circulation and exchange in choked marginal seas
Author Posting. © American Meteorological Society, 2008. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 38 (2008): 2639-2661, doi:10.1175/2008JPO3946.1.A theory for the exchange between a rotating, buoyancy-forced marginal sea and an ocean is developed and tested numerically. Cooling over the marginal sea leads to sinking and sets up a two-layer exchange flow, with a warm surface layer entering from the ocean and a cool layer exiting at depth. The connecting strait is sufficiently narrow and shallow to cause the exchange flow to be hydraulically controlled. The incoming surface layer forms a baroclinically unstable boundary current that circles the marginal sea in a cyclonic sense and feeds heat to the interior by way of eddies. Consistent with the overall heat and volume balances for the marginal sea, there is a continuous family of hydraulically controlled states with critical flow at the most constricted section of the strait. Included in this family is a limiting “maximal-exchange” solution with two sections of hydraulic control in the strait and with fixed layer depths at the most constricted section. The state of exchange for a given forcing is predicted using a theory that assumes energy conservation over a certain path connecting the strait to the marginal sea or, in some cases, the ocean. Depending on the configuration of the exchange, long-wave information may be blocked from entering the strait from the marginal sea, from the open ocean, or both. The scenario that holds determines what is predicted and what needs to be input. Numerical tests of the prediction for the temperature difference and the state of exchange are carried out for straits with a pure contraction in width and for a constant width strait with a topographic sill. The comparison is reasonable in most cases, though the numerical model is not able to reproduce cases of multiple states predicted by the theory for certain forcing values. The analytical model is an alternative to the Price and Yang and Siddall et al. models of a marginal sea outflow.This work was supported by the
National Science Foundation under Grants OCE-0525729
and OCE-0423975
Design of Phase 3 Studies Evaluating Vixotrigine for Treatment of Trigeminal Neuralgia
Purpose: Vixotrigine (BIIB074) is a voltage- and use-dependent sodium channel blocker. These studies will evaluate the efficacy and safety of vixotrigine in treating pain experienced by patients with trigeminal neuralgia (TN) using enriched enrollment randomized withdrawal trial designs.
Patients and Methods: Two double-blind randomized withdrawal studies are planned to evaluate the efficacy and safety of vixotrigine compared with placebo in participants with TN (NCT03070132 and NCT03637387). Participant criteria include ≥ 18 years old who have classical, purely paroxysmal TN diagnosed ≥ 3 months prior to study entry, who experience ≥ 3 paroxysms of pain/day. The two studies will include a screening period, 7-day run-in period, a 4- or 6-week single-dose-blind dose-optimization period (Study 1) or 4-week open-label period (Study 2), and 14-week double-blind period. Participants will receive vixotrigine 150 mg orally three times daily in the dose-optimization and open-label periods. The primary endpoint of both studies is the proportion of participants classified as responders at Week 12 of the double-blind period. Secondary endpoints include safety measures, quality of life, and evaluation of vixotrigine population pharmacokinetics.
Conclusion: There is a need for an effective, well-tolerated, noninvasive treatment for the neuropathic pain associated with TN. The proposed studies will evaluate the efficacy and safety of vixotrigine in treating pain experienced by patients with TN
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