395 research outputs found

    Using Linked Household-level Datasets to Explain Consumer Response to BSE in Canada

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    Household-level Canadian meat purchases from 2002-2008, household-level egg purchases from 2002-2005 and Food Opinion Survey in 2008 were used to understand how consumers who have different concerns about nutrition react to BSE events and how beef consumption after BSE discoveries were shaped by consumers concerns of food safety and their trust of government and the industry decision makers. Three measures of beef purchased were used to explore consumers’ reaction. A random effects logit model was applied to test whether any beef purchased during a given month. Consumption in terms of unit purchases was measured with a random effects Negative Binomial model and consumption in terms of beef expenditure was measured with a standard random effects model. Consumer behaviors in Alberta differed from Ontario. Consumer reactions to BSE in Alberta were stronger than Ontario. Overall, the more risk consumers attached to BSE, the less beef they purchased in both provinces. Random effects in the three models controlled for unobserved but persistent aspects of households and changed the sign of estimated effects of demographic variables.BSE, mad cow disease, food safety, consumer behavior, Canada, Agribusiness, Agricultural and Food Policy, Consumer/Household Economics, Food Consumption/Nutrition/Food Safety, Marketing,

    Making academia more accessible

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    Academia can be a challenging place to work and academics who have a disability, neurodiversity or chronic illness are further disadvantaged, as non-stereotypical ways of working are not necessarily supported or catered for. The remit of this paper is to provide practical ideas and recommendations to address accessibility issues in events and conferences as a first step to improving existing working conditions. We start with providing a brief overview of and background to the issues of ableism, disabilities, chronic illnesses and neurodiversities in academia. We then offer a detailed description of the organisational and developmental strategies relating to the Ableism in Academia conference to practically demonstrate how accessibility can be achieved. Despite vast literature available on theorisations of reasonable adjustments and some individual handbooks on conference accessibility, noted the absence of a systematic write-up of a case study that would demonstrate the thought processes required for the organisation of a fully accessible and inclusive event. This paper provides almost a step-by-step rationale and rundown of the decisions that had to be taken in order to facilitate an accessible event. After a brief consideration of challenges we encountered along the way, we share personal reflections regarding the event and future developments

    Molecular-Diffusive Effects in Penetrative Convection

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    An experimental study was performed to investigate the influence of molecular diffusion on turbulent entrainment during penetrative convection. The entrainment coefficient E was determined as a function of the Richardson number Ri and Peclet number Pe. It appears that, in parameter ranges 6

    The Taming of Closed Time-like Curves

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    We consider a R1,d/Z2R^{1,d}/Z_2 orbifold, where Z2Z_2 acts by time and space reversal, also known as the embedding space of the elliptic de Sitter space. The background has two potentially dangerous problems: time-nonorientability and the existence of closed time-like curves. We first show that closed causal curves disappear after a proper definition of the time function. We then consider the one-loop vacuum expectation value of the stress tensor. A naive QFT analysis yields a divergent result. We then analyze the stress tensor in bosonic string theory, and find the same result as if the target space would be just the Minkowski space R1,dR^{1,d}, suggesting a zero result for the superstring. This leads us to propose a proper reformulation of QFT, and recalculate the stress tensor. We find almost the same result as in Minkowski space, except for a potential divergence at the initial time slice of the orbifold, analogous to a spacelike Big Bang singularity. Finally, we argue that it is possible to define local S-matrices, even if the spacetime is globally time-nonorientable.Comment: 37 pages, LaTeX2e, uses amssymb, amsmath and epsf macros, 8 eps and 3 ps figures; (v2): Two additional comments + one reference added; (v3): corrections in discussion of CTCs + some clarification

    S-matrix elements and off-shell tachyon action with non-abelian gauge symmetry

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    We propose that there is a unique expansion for the string theory S-matrix elements of tachyons that corresponds to non-abelian tachyon action. For those S-matrix elements which, in their expansion, there are the Feynman amplitudes resulting from the non-abelian kinetic term, we give a prescription on how to find the expansion. The gauge invariant action is an αâ€Č\alpha' expanded action, and the tachyon mass mm which appears as coefficient of many different couplings, is arbitrary. We then analyze in details the S-matrix element of four tachyons and the S-matrix element of two tachyons and two gauge fields, in both bosonic and superstring theories, in favor of this proposal. In the superstring theory, the leading terms of the non-abelian gauge invariant couplings are in agreement with the symmetrised trace of the direct non-abelian generalization of the tachyonic Born-Infeld action in which the tachyon potential is consistent with V(T)=eπαâ€Čm2T2V(T)=e^{\pi\alpha' m^2T^2}. In the bosonic theory, on the other hand, the leading terms are those appear in superstring case as well as some other gauge invariant couplings which spoils the symmetrised trace prescription. These latter terms are zero in the abelian case.Comment: Latex, 27 pages, no figures,v4:change the introduction section, add some notes to clarify the idea, add reference

    Bridging geometries and potentials in DBI cosmologies

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    We investigate the link between the warp function and the potential in DBI cosmologies in connection with the possibility they represent power-law solutions. A prescription is given to take advantage of the known result that given a warp factor there is always a choice of potential resulting in a constant ratio between pressure and energy density. The method is illustrated with examples with interesting models for either the warp factor or the potential. We complete this investigation by giving a recipe to exploit symmetries in order to generate new solutions from existing ones; this method can be applied, for instance, to the power-law cosmologies obtained using our prescription.Comment: 7 pages, 3 figures, revte

    Differences in the pattern and regulation of mineral deposition in human cell lines of osteogenic and non-osteogenic origin

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    Bone marrow-derived mesenchymal stem cells (MSCs) are widely used as a cellular model of bone formation, and can mineralize in vitro in response to osteogenic medium (OM). It is unclear, however, whether this property is specific to cells of mesenchymal origin. We analysed the OM response in 3 non-osteogenic lines, HEK293, HeLa and NTera, compared to MSCs. Whereas HEK293 cells failed to respond to OM conditions, the 2 carcinoma-derived lines NTera and HeLa deposited a calcium phosphate mineral comparable to that present in MSC cultures. However, unlike MSCs, HeLa and NTera cultures did so in the absence of dexamethasone. This discrepancy was confirmed, as bone morphogenetic protein inhibition obliterated the OM response in MSCs but not in HeLa or NTera, indicating that these 2 models can deposit mineral through a mechanism independent of established dexamethasone or bone morphogenetic protein signalling

    The Physics of Star Cluster Formation and Evolution

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    © 2020 Springer-Verlag. The final publication is available at Springer via https://doi.org/10.1007/s11214-020-00689-4.Star clusters form in dense, hierarchically collapsing gas clouds. Bulk kinetic energy is transformed to turbulence with stars forming from cores fed by filaments. In the most compact regions, stellar feedback is least effective in removing the gas and stars may form very efficiently. These are also the regions where, in high-mass clusters, ejecta from some kind of high-mass stars are effectively captured during the formation phase of some of the low mass stars and effectively channeled into the latter to form multiple populations. Star formation epochs in star clusters are generally set by gas flows that determine the abundance of gas in the cluster. We argue that there is likely only one star formation epoch after which clusters remain essentially clear of gas by cluster winds. Collisional dynamics is important in this phase leading to core collapse, expansion and eventual dispersion of every cluster. We review recent developments in the field with a focus on theoretical work.Peer reviewe
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