1,325 research outputs found
Food Lion and the Media’s Liability for Newsgathering Torts: A Symposium Preview
Abans de l'arribada de Pere Alberch a la catedral de Barcelona, el magisteri de l'orgue havia estat en mans de l'organista Joan Ferrer, el qual l'exercà entre 1515 i 1536, essent mestre de cant entre 1513 i 1517. La identitat de l'organista de la catedral de Barcelona correspon a la del compositor «Johannes Ffarer», autor del motet «Domine non secundum» del Cancionero musical de Segovia (CMS). La identificació entre «Johannes Ffarer» i Joan Ferrer, i la presència del seu motet processional «Domine non secundum» juntament amb la de l'himne «Conditor alme siderunt» de Marturià Prats, fan palesa la recepció que la capella flamenca va fer del repertori polifònic d'aquests dos compositors catalans, les obres dels quals es devien incorporar al cançoner durant el prolongat sojorn que la capella de Carles I va fer a Barcelona, en el transcurs de l'any 1519. D'altra banda, i grà cies a la documentació capitular de les seus de Vic, Tortosa i Tarragona, sabem que Marturià Prats, i també Antoni Marlet, romanien vinculats a la capella nobilià ria que l'infant Enric, comte d'Empúries, mantenia al seu palau del carrer Ample de Barcelona. En el marc del context urbà , social i musical de la Barcelona de principis del segle xvi no costa gaire d'imaginar com devien sovintejar els contactes, i, amb ells, les avinences i els intercanvis musicals en-
tre els músics de la capella flamenca i els de les capelles nobilià ries dels Cardona, l'infant Enric, els Montcada, a banda dels cantors de la catedral i dels de les grans parròquies de la ciutat. Un esdeveniment d'aquestes caracterÃstiques pot ajudar a explicar el motiu de la presència de les dues obres de Joan Ferrer i Marturià Prats en el CMS, convivint amb la riquesa del seu repertori francoflamenc i castellà .Before Pere Alberch arrived at Barcelona Cathedral, the organ master had been the organist Joan Ferrer in the period between 1515 and 1536, and he had also been the magister cantus between 1513 and 1517. The identity of the organist of Barcelona Cathedral corresponds to that of the composer Johannes Ffarer, who was the author of the motet Domine non secundum of the Cancionero musical de Segovia. The identification between Johannes Ffarer and Joan Ferrer, and the presence of his processional motet Domine non secundum together with that of the hymn Conditor alme siderunt of Marturià Prats, evidence the Flemish chapel's reception of the polyphonic repertoire of these two Catalan composers, whose works must have been added to the cancionero or song-book during the long stay of Charles I's chapel in Barcelona in the course of the year 1519. Moreover, thanks to the chapter documents of the cathedrals of Vic, Tortosa and Tarragona, we know that Marturià Prats as well as Antoni Marlet remained attached to the noble chapel which Prince Henry, Count of Empúries, kept in his palace at Carrer Ample in Barcelona. Within the urban, social and musical context of the Barcelona of the early 16th century, it is easy to imagine how frequent the contacts must have been and consequently the understandings and musical exchanges between the musicians of the Flemish chapel and those of the noble chapels of the Cardonas, Prince Henry, the Montcadas, etc., as well as the singers of the Cathedral and those of the major parish churches of the city. An event of this type could help to explain the reason for the presence of the two works of Joan Ferrer and Marturià Prats in the CMS, together with the rich Franco-Flemish and Castilian repertoire to be found there
Stormwater Management Performance of Green Roofs
Green roofs are gaining recognition in North America as effective tools for managing stormwater runoff in urban areas. A greater understanding of how green roofs perform with respect to fundamental stormwater management criteria, such as stormwater retention and peak flow attenuation is required. This study investigated the impact that changing climates have on the retention performance of three green roofs in London, Calgary, and Halifax. It was found that Calgary (67%) has significantly better retention performance then both London (48%) and Halifax (34%). However, London retained the greatest volume of stormwater (758 mm), followed by Halifax (517 mm) then Calgary (474 mm).
Further monitoring of the hydrologic response for a fourth green roof in London Ontario was conducted to identify and measure the fundamental processes of peak attenuation on a green roof. It was determined that field capacity is a quantifiable point, after which peak attenuation performance significantly decreases. Before field capacity peak attenuation is governed by capillary storage (72%) and routing (7%). After field capacity, gravity storage provides peak attenuation (22%) and drainage routing plays a larger role (11%). A predictive model was developed using Richards equation to simulate the outflow hydrographs of a green roof. Model results show that there is no significant difference from observed data for the performance metrics (ie., water storage, drainage, and peak flow rate).
For the first time in green roof literature the impact of climate on retention was assessed, the processes of peak attenuation were quantified, and an accurate predictive model was presented
Electrostatic charging of spacecraft in geosynchronous orbit
Any satellite whose orbit passes through the terrestrial magnetosphere will encounter several plasma regimes with widely differing temperatures, densities and compositions. The spacecraft itself will act as a plasma probe; each surface element changes its potential until no net current flows between it and the plasma. Differential charge build-up between adjacent surfaces (for example of different material or geometrical characteristics) can induce electrostatic discharges. The resulting current pulse, or RF interference gives rise to 'operational anomalies' (spurious switchings, telemetry drop-outs etc), or in extreme cases leads to permanent damage (eg short circuits in strings of solar cells). This thesis is a study of the spacecraft charging phenomenon applicable to satellites in geosynchronous orbit. Results are derived from three sources. Firstly, Meteosat F2 (a meteorological satellite launched by ESA in July 1981) which carried an electron spectrometer to make direct measurements of the geosynchronous orbit electron environment, and in addition, suffered a series of operational anomalies and surface charging events. Secondly, an experimental test programme was undertaken using a monoenergetic electron beam to irradiate some common spacecraft surface materials, and thereby examine their electrostatic charging properties. Thirdly, numerical simulation codes were written and employed to model several different situations, ranging from the electron beam experiment to a full three-dimensional simulation of Meteosat F2. Analysis of the electron beam irradiation data shows that the surface conductivity of some common insulating materials (Kapton and Teflon) plays a much greater role in the current balance equation than was thought previously. Furthermore, the process whereby bulk and surface conductivity is enhanced by large electric fields (deviations from pure Ohmic behaviour) is also shown to be a significant factor in the current balance equation. These results are of importance both to satellite surface design, and to high voltage insulating systems. Spacecraft charging simulation codes must accurately model the detailed interaction between plasma energy spectra and the energy dependent material surface properties (such as secondary electron emission). The thesis demonstrates that it is vital to use real, measured spectra (for example from the Meteosat spectrometer) rather than simple Maxwellian plasma definitions, if spacecraft charging is to be modelled successfully. Also, the need for an improved database of reliable secondary electron yield measurements is demonstrated
Effects of Changing Environments on Survival of a Widely Distributed Ungulate
Widely distributed species are experiencing a continual pattern of range shifts due to anthropogenic expansion and climate change, forcing these species into novel environments and out of critical habitat. The ability to estimate current and forecasted states of demographic parameters of species distributed along a gradient of environments is becoming increasingly important in a time of large-scale environmental change. Consulting models that provide temporally relevant estimates of population dynamics based on the latest realizations of environmental conditions can allow for informed, quick and decisive conservation and management actions. Modelling the drivers of demography across a wide range of environmental conditions will provide a more comprehensive understanding of how species will respond to novel environments. In this study we provide an example of relating seasonal-environmental variables to survival in a widely distributed ungulate species. We used a mule deer (Odocoileus hemionus) survival dataset collected in Utah with seven sites distributed across the multiple ecoregions of the state, allowing for the elucidation of relationships across a variety of environmental conditions. Multivariate analyses predicting survival of young and adult females were performed using geographic location, elevation, and seasonal satellite-derived primary productivity data and weather variables. We developed frameworks for estimating past and current states of survival and predicting short-term (sub-year) forecasts of survival. Furthermore, we investigated adaptive modelling techniques for increasing the certainty of the forecasted predictions of survival. We found that increased winter precipitation had a negative effect on survival across the state. Survival was lower in the northern region of the state and in higher elevations. Furthermore, measures of summer primary productivity had a positive relationship with survival. Lastly, our adaptive modelling demonstration shows that uncertainty of forecasted survival predictions can be reduced with the addition of data. This study provides a framework for developing models that will provide invaluable information to managers in a time of large-scale environmental change
The problems with prediction : the dark room problem and the scope dispute
There is a disagreement over the scope of explanation for predictive processing. While some proponents think that it is best motivated from—and indeed comprises an explanation of—biological self-organization, others maintain that it should only be a theory of neurocognitive function, or even just of some limited domain of neurocognitive function. Something that these theorists share is an interest in addressing the dark-room problem: at its most naïve, if action is driven by the minimization of surprise then why don’t cognitive creatures act to minimize stimuli in general? The dark-room problem is in fact best conceived as a cluster of related concerns, rather than as a single argument against action-oriented predictive processing. These have to do with: i) whether PP (predictive processing) has any substantive empirical content when it is pitched in very general domains; ii) whether a specification can be given of the environmental niche that action moves the organism to occupy, and which is not the dark room; and iii) whether an adequate account can be given within this specification of exploratory and exploitative behaviours. There are interesting conceptual relations between the dark-room problem and the scope dispute. As the putative scope of predictive processing gets wider (culminating in the free energy principle), the resources that are available for answering the concerns about niche-specification become very rich. But increasingly puzzling problems arise as to the implementation of surprise-minimisation within non-paradigmatically cognitive biological systems. On the other hand, under more restrictive construals of the scope of predictive processing, there are new difficulties standing in the way of niche-specification, and new questions about the interface between surprise-minimisation and model-free cognition undermine the promise of predictive processing as a unifier of theories of neurocognitive function in subordinate domains. In this paper I make explicit the dialectic between proponents and critics in order to show how the two problems are related
Numerical Computations of Generalized Korteweg-de Vries (KdV) equations
We consider the following generalized Korteweg-deVries (KdV) equation ++2+−=0.
The above equation is the generalized version of the KDV equation ++2+=0.
Here =(,) is a scalar function of ∈and ≥0, while \u3e0 is a parameter. This equation is used to model the unidirectional propagation of water waves. The scalar represents the amplitude of the wave.
In this presentation we investigate the various limits of the solutions of the generalized equation as one or more of the parameters as ,, and tend to zero. This is carried out through numerical computations using the pseudo-spectral method
A Zero-Parameter Extension of General Relativity with Varying Cosmological Constant
We provide a new extension of general relativity (GR) which has the
remarkable property of being more constrained than GR plus a cosmological
constant, having one less free parameter. This is implemented by allowing the
cosmological constant to have a consistent space-time variation, through coding
its dynamics in the torsion tensor. We demonstrate this mechanism by adding a
`quasi-topological' term to the Einstein action, which naturally realizes a
dynamical torsion with an automatic satisfaction of the Bianchi identities.
Moreover, variation of the action with respect to this dynamical
fixes it in terms of other variables, thus providing a scenario with less
freedom than general relativity with a cosmological constant. Once matter is
introduced, at least in the homogeneous and isotropic reduction, is
uniquely determined by the field content of the model. We make an explicit
construction using the Palatini formulation of GR and describe the striking
properties of this new theory. We also highlight some possible extensions to
the theory. A companion paper [1] explores the Friedmann--Robertson--Walker
reduction for cosmology, and future work will study Solar System tests of the
theory.Comment: Companion paper to arXiv:1905.10382. Minor updates to match published
versio
The cosmology of minimal varying Lambda theories
Inserting a varying Lambda in Einstein's field equations can be made
consistent with the Bianchi identities by allowing for torsion, without the
need to add scalar field degrees of freedom. In the minimal such theory, Lambda
is totally free and undetermined by the field equations in the absence of
matter. Inclusion of matter ties Lambda algebraically to it, at least when
homogeneity and isotropy are assumed, i.e. when there is no Weyl curvature. We
show that Lambda is proportional to the matter density, with a proportionality
constant depending on the equation of state. Unfortunately, the proportionality
constant becomes infinite for pure radiation, ruling out the minimal theory
prima facie despite of its novel internal consistency. It is possible to
generalize the theory still without the addition of kinetic terms, leading to a
new algebraically-enforced proportionality between Lambda and the matter
density. Lambda and radiation may now coexist in a form consistent with Big
Bang Nucleosynthesis, though this places strict constraints on the single free
parameter of the theory, . In the matter epoch Lambda behaves just like
a dark matter component. Its density is proportional to the baryonic and/or
dark matter, and its presence and gravitational effects would need to be
included in accounting for the necessary dark matter in our Universe. This is a
companion paper to Ref. [1] where the underlying gravitational theory is
developed in detail.Comment: Companion paper to arXiv:1905.10380. Minor updates to match published
versio
- …