13,368 research outputs found
Changing perceptions of preservice teachers : innovations in middle schooling teacher education
For the past twenty years, the disengagement of early adolescents has been the focus of much of the literature related to middle schooling. In response, some universities in Australia have introduced teacher education programs that focus upon graduating specialised middle schooling teachers. Constructing such programs is at the centre of much debate and discussion, however, it is advocated that positive futures for early adolescents can be enhanced through quality middle schooling teacher education programs (Education Queensland, 2004). At a Queensland university campus, middle schooling elective units were introduced as part of the Bachelor of Education (primary) degree. The design of the units was to support preservice teachers to gain the theoretical and pedagogical knowledge to engage and promote early adolescent learning. An innovative approach to the delivery of the units was promoted by a partnership agreement between local schools and the campus. The partnership allowed preservice teachers to combine university classes with opportunities to visit exemplary classrooms to observe, participate and reflect upon middle school teaching practices. The aim of this study was to explore and describe the 38 first-year preservice teachersâ perceptions of their first middle schooling elective unit and to ascertain whether the combination of university classes and school-based experiences assisted their development of middle schooling concepts and approaches. Data were gathered using pre-test and post-test questionnaires combined with guided written reflections to record their views before, after and during the unit delivery. Results indicated that initially 34 preservice teachers had little understanding of middle schooling concepts and pedagogical practices, however, 11 participants recognised that bullying and peer pressure were issues experienced by early adolescents. The collation of the written reflections supported the combined delivery of the middle years unit further supporting the inclusion of school experiences with university delivered units
Fermionic Quasi-free States and Maps in Information Theory
This paper and the results therein are geared towards building a basic
toolbox for calculations in quantum information theory of quasi-free fermionic
systems. Various entropy and relative entropy measures are discussed and the
calculation of these reduced to evaluating functions on the one-particle
component of quasi-free states.
The set of quasi-free affine maps on the state space is determined and fully
characterized in terms of operations on one-particle subspaces. For a subclass
of trace preserving completely positive maps and for their duals, Choi matrices
and Jamiolkowski states are discussed.Comment: 19 page
New technologies for urban designers: the VENUE project
In this report, we first outline the basic idea of VENUE. This involves developing digital tools froma foundation of geographic information systems (GIS) software which we then apply to urbandesign, a subject area and profession which has little tradition in using such tools. Our project wasto develop two types of tool, namely functional analysis based on embedding models of movementin local environments into GIS based on ideas from the field of space syntax; and secondlyfashioning these ideas in a wider digital context in which the entire range of GIS technologies werebrought to bear at the local scale. By local scale, we mean the representation of urban environmentsfrom about 1: 500 to around 1: 2500
GIS and urban design
Although urban planning has used computer models and information systems sincethe 1950s and architectural practice has recently restructured to the use of computeraideddesign (CAD) and computer drafting software, urban design has hardly beentouched by the digital world. This is about to change as very fine scale spatial datarelevant to such design becomes routinely available, as 2dimensional GIS(geographic information systems) become linked to 3dimensional CAD packages,and as other kinds of photorealistic media are increasingly being fused with thesesoftware. In this chapter, we present the role of GIS in urban design, outlining whatcurrent desktop software is capable of and showing how various new techniques canbe developed which make such software highly suitable as basis for urban design.We first outline the nature of urban design and then present ideas about how varioussoftware might form a tool kit to aid its process. We then look in turn at: utilisingstandard mapping capabilities within GIS relevant to urban design; buildingfunctional extensions to GIS which measure local scale accessibility; providingsketch planning capability in GIS and linking 2-d to 3-d visualisations using low costnet-enabled CAD browsers. We finally conclude with some speculations on thefuture of GIS for urban design across networks whereby a wide range of participantsmight engage in the design process digitally but remotely
The Velocity Field from Type Ia Supernovae Matches the Gravity Field from Galaxy Surveys
We compare the peculiar velocities of nearby SNe Ia with those predicted by
the gravity fields of full sky galaxy catalogs. The method provides a powerful
test of the gravitational instability paradigm and strong constraints on the
density parameter beta = Omega^0.6/b. For 24 SNe Ia within 10,000 km/s we find
the observed SNe Ia peculiar velocities are well modeled by the predictions
derived from the 1.2 Jy IRAS survey and the Optical Redshift Survey (ORS). Our
best is 0.4 from IRAS, and 0.3 from the ORS, with beta>0.7 and
beta<0.15 ruled out at 95% confidence levels from the IRAS comparison.
Bootstrap resampling tests show these results to be robust in the mean and in
its error. The precision of this technique will improve as additional nearby
SNe Ia are discovered and monitored.Comment: 16 pages (LaTex), 3 postscript figure
Maximum-Likelihood Comparisons of Tully-Fisher and Redshift Data: Constraints on Omega and Biasing
We compare Tully-Fisher (TF) data for 838 galaxies within cz=3000 km/sec from
the Mark III catalog to the peculiar velocity and density fields predicted from
the 1.2 Jy IRAS redshift survey. Our goal is to test the relation between the
galaxy density and velocity fields predicted by gravitational instability
theory and linear biasing, and thereby to estimate where is the linear bias parameter for IRAS galaxies.
Adopting the IRAS velocity and density fields as a prior model, we maximize the
likelihood of the raw TF observables, taking into account the full range of
selection effects and properly treating triple-valued zones in the
redshift-distance relation. Extensive tests with realistic simulated galaxy
catalogs demonstrate that the method produces unbiased estimates of
and its error. When we apply the method to the real data, we model the presence
of a small but significant velocity quadrupole residual (~3.3% of Hubble flow),
which we argue is due to density fluctuations incompletely sampled by IRAS. The
method then yields a maximum likelihood estimate
(1-sigma error). We discuss the constraints on and biasing that follow
if we assume a COBE-normalized CDM power spectrum. Our model also yields the
1-D noise noise in the velocity field, including IRAS prediction errors, which
we find to be be 125 +/- 20 km/sec.Comment: 53 pages, 20 encapsulated figures, two tables. Submitted to the
Astrophysical Journal. Also available at http://astro.stanford.edu/jeff
Overconstrained dynamics in galaxy redshift surveys
The least-action principle (LAP) method is used on four galaxy redshift
surveys to measure the density parameter Omega_m and the matter and
galaxy-galaxy power spectra. The datasets are PSCz, ORS, Mark III and SFI. The
LAP method is applied on the surveys simultaneously, resulting in an
overconstrained dynamical system that describes the cosmic overdensities and
velocity flows. The system is solved by relaxing the constraint that each
survey imposes upon the cosmic fields. A least-squares optimization of the
errors that arise in the process yields the cosmic fields and the value of
Omega_m that is the best fit to the ensemble of datasets. The analysis has been
carried out with a high-resolution Gaussian smoothing of 500 km/s and over a
spherical selected volume of radius 9,000 km/s. We have assigned a weight to
each survey, depending on their density of sampling, and this parameter
determines their relative influence in limiting the domain of the overall
solution. The influence of each survey on the final value of Omega_m, the
cosmographical features of the cosmic fields and the power spectra largely
depends on the distribution function of the errors in the relaxation of the
constraints. We find that PSCz and Mark III are closer to the final solution
than ORS and SFI. The likelihood analysis yields Omega_m= 0.37\pm 0.01 to
1sigma level. PSCz and SFI are the closest to this value, whereas ORS and Mark
III predict a somewhat lower Omega_m. The model of bias employed is a
scale-dependent one, and we retain up to 42 bias coefficients b_{rl} in the
spherical harmonics formalism. The predicted power spectra are estimated in the
range of wavenumbers 0.02-0.49h Mpc^{-1}, and we compare these results with
measurements recently reported in the literature.Comment: 10 pages, no figure
Nearby Optical Galaxies: Selection of the Sample and Identification of Groups
In this paper we describe the Nearby Optical Galaxy (NOG) sample, which is a
complete, distance-limited (6000 km/s) and magnitude-limited
(B14) sample of 7000 optical galaxies. The sample covers 2/3 (8.27
sr) of the sky () and appears to have a good completeness in
redshift (98%). We select the sample on the basis of homogenized corrected
total blue magnitudes in order to minimize systematic effects in galaxy
sampling.
We identify the groups in this sample by means of both the hierarchical and
the percolation {\it friends of friends} methods. The resulting catalogs of
loose groups appear to be similar and are among the largest catalogs of groups
presently available. Most of the NOG galaxies (60%) are found to be
members of galaxy pairs (580 pairs for a total of 15% of objects)
or groups with at least three members (500 groups for a total of
45% of objects). About 40% of galaxies are left ungrouped (field
galaxies). We illustrate the main features of the NOG galaxy distribution.
Compared to previous optical and IRAS galaxy samples, the NOG provides a denser
sampling of the galaxy distribution in the nearby universe. Given its large sky
coverage, the identification of groups, and its high-density sampling, the NOG
is suited for the analysis of the galaxy density field of the nearby universe,
especially on small scales.Comment: 47 pages including 6 figures. Accepted for publication in Ap
Galaxy Distances in the Nearby Universe: Corrections For Peculiar Motions
By correcting the redshift--dependent distances for peculiar motions through
a number of peculiar velocity field models, we recover the true distances of a
wide, all-sky sample of nearby galaxies (~ 6400 galaxies with velocities
cz<5500 km/s), which is complete up to the blue magnitude B=14 mag. Relying on
catalogs of galaxy groups, we treat ~2700 objects as members of galaxy groups
and the remaining objects as field galaxies.
We model the peculiar velocity field using: i) a cluster dipole
reconstruction scheme; ii) a multi--attractor model fitted to the Mark II and
Mark III catalogs of galaxy peculiar velocities. According to Mark III data the
Great Attractor has a smaller influence on local dynamics than previously
believed, whereas the Perseus-Pisces and Shapley superclusters acquire a
specific dynamical role. Remarkably, the Shapley structure, which is found to
account for nearly half the peculiar motion of the Local Group, is placed by
Mark III data closer to the zone of avoidance with respect to its optical
position.
Our multi--attractor model based on Mark III data favors a cosmological
density parameter Omega ~ 0.5 (irrespective of a biasing factor of order
unity). Differences among distance estimates are less pronounced in the ~ 2000
- 4000 km/s distance range than at larger or smaller distances. In the last
regions these differences have a serious impact on the 3D maps of the galaxy
distribution and on the local galaxy density --- on small scales.Comment: 24 pages including (9 eps figures and 7 tables). Figures 1,2,3,4 are
available only upon request. Accepted by Ap
Wear and Friction Modeling on Lifeboat Launch Systems
The RNLI provides search and rescue cover along the UK and RoI coast using a variety of lifeboats
and launch techniques. In locations where there is no natural harbour it is necessary to use a slipway
to launch the lifeboat into the sea. Lifeboat slipway stations consist of an initial section where the
boat is held on rollers followed by an inclined keelway lined with low friction composite materials,
the lifeboat is released from the top of the slipway and proceeds under its own weight into the water.
The lifeboat is later recovered using a winch line. It is common to manually apply grease to the
composite slipway lining before each launch and recovery in order to ensure sufficiently low friction
for successful operation. With the introduction of the Tamar class lifeboat it is necessary to upgrade
existing boathouses and standardise slipway operational procedures to ensure consistent operation.
The higher contact pressures associated with the new lifeboat have led to issues of high friction and
wear on the composite slipway linings and the manual application of grease to reduce friction is to be
restricted due to environmental impact and cost factors. This paper presents a multidisciplinary
approach to modelling slipway panel wear and friction using tribometer testing in conjunction with
finite element analysis and slipway condition surveys to incorporate common real-world effects such
as panel misalignments. Finally, it is shown that a freshwater lubrication system is effective,
reducing cost and environmental impacts while maintaining good friction and wear performance
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