415,923 research outputs found
Affordances of Historic Urban Landscapes: an Ecological Understanding of Human Interaction with the Past
Heritage has been defined differently in European contexts. Despite differences, a common challenge for historic urban landscape management is the integration of tangible and intangible heritage. Integration demands an active view of perception and human-landscape interaction where intangible values are linked to specific places and meanings are attached to particular cultural practices and socio-spatial organisation. Tangible and intangible values can be examined as part of a system of affordances (potentialities) a place, artefact or cultural practice has to offer. This paper discusses how an ‘affordance analysis’ may serve as a useful tool for the management of historic urban landscapes
A Phenomenological Study of the Experiences of Middle School Teachers Working with Girls with High Functioning Autism
Graduate
Applie
Diffractive Results from the Tevatron
Hard diffraction in events with dijets and rapidity gaps has been studied by
D\O and CDF for three processes: hard color singlet exchange, hard single
diffraction, and hard double pomeron exchange, using Tevatron data at
= 630 GeV and 1.8 TeV. Measurements of rates, and
dependencies are presented and comparisons made with predictions of
several models.Comment: Presented at DPF99, 8 pages, 6 figure
Orion Revisited - I. The massive cluster in front of the Orion Nebula Cluster
The aim of this work is to characterize the stellar population between Earth
and the Orion A molecular cloud where the well known star formation benchmark
Orion Nebula Cluster (ONC) is embedded. We use the denser regions the Orion A
cloud to block optical background light, effectively isolating the stellar
population in front of it. We then use a multi-wavelength observational
approach to characterize the cloud's foreground stellar population. We find
that there is a rich stellar population in front of the Orion A cloud, from
B-stars to M-stars, with a distinct 1) spatial distribution, 2) luminosity
function, and 3) velocity dispersion from the reddened population inside the
Orion A cloud. The spatial distribution of this population peaks strongly
around NGC 1980 (iota Ori) and is, in all likelihood, the extended stellar
content of this poorly studied cluster. We infer an age of ~4-5 Myr for NGC
1980 and estimate a cluster population of the order of 2000 stars, which makes
it one of the most massive clusters in the entire Orion complex. What is
currently taken in the literature as the ONC is then a mix of several
intrinsically different populations, namely: 1) the youngest population,
including the Trapezium cluster and ongoing star formation in the dense gas
inside the nebula, 2) the foreground population, dominated by the NGC 1980
cluster, and 3) the poorly constrained population of foreground and background
Galactic field stars. Our results support a scenario where the ONC and L1641N
are not directly associated with NGC 1980, i.e., they are not the same
population emerging from its parental cloud, but are instead distinct
overlapping populations. This result calls for a revision of most of the
observables in the benchmark ONC region (e.g., ages, age spread, cluster size,
mass function, disk frequency, etc.). (abridged)Comment: Version 2 includes comments and clarifications from John Tobin,
Nicola Da Rio, and Lynne Hillenbrand (minor clarifying changes were made to
Figures 1, 8, and 10). A&A accepted (15 pages, 10 figures). Higher resolution
figures available upon reques
Theses towards a new natural philosophy
In this paper I address some philosophical questions regarding the impact quantum
mechanics has in the classical conceptions about reality and knowledge. I stress that
onto-gnosiological realism still is an option to the issues regarding the relationship
between knowledge and reality. Rejecting some radical aspects of Copenhagen
interpretation of quantum formalism, I emphasize the advantages of de Broglie’s
realistic and causal model. To finish with, I discuss the limits of the Cartesian concept
of matter and the split between matter and mind
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