1,290 research outputs found
Teachersâ Perceptions of Integrating Students withBehaviour Disorders: Challenges and Strategies
This study is a preliminary exploratory investigation into teachersâ perceptions of both the challenges involved in integrating children with behavioural problems and potential strategies that may be used to deal with those problems. There were two separate but related phases: Phase One was the creation of the Teachersâ Perceptions of Successful Integration (TPSI) survey; Phase Two was an initial test of the survey on 53 teachers. Based on Phase Two, results indicate that uncontrollable, dangerous behaviour and time demands placed on the teacher were the most challenging aspects of integrating this student group. Successful strategies included creating structured classrooms with positive atmospheres, having expectations that are known to the child, actively involving the child in the intervention program, establishing relationships of trust between students and teachers, and providing adequate teacher training in the area of behaviour disorders. Identifi ed unsuccessful strategies were yelling at the child and expulsion. Educational implications of the study are discussed
Ultraviolet (UV) transparent plastic claddings warm crops and improve water use efficiency
Advances in the manufacturing of plastic cladding for protected crop cultivation have resulted in wavelength selective plastics capable of manipulating the transmission of solar radiation to include ultraviolet (UV: 280-400 nm). Commercial growers already utilising these plastics report early maturity associated with warmer crops. We hypothesised that UV-B radiation causes partial stomatal closure that reduces stomatal conductance and transpiration rate, thereby increasing leaf temperature (relative to air temperature). We tested this hypothesis by investigating leaf gas exchange and temperature responses of individual tomato leaves to UV-B and UV-A radiation provided by UV lamps in a controlled environment. Transient (90 min) exposure to UV-B radiation decreased stomatal conductance but had minimal impact on photosynthesis, thus increasing leaf temperature and instantaneous water use efficiency. Should this enhanced water use efficiency also occur at a whole plant/canopy scale, these responses may benefit growers of protected crops in arid climates where plastic clad polytunnels are often utilised. © 2020 International Society for Horticultural Science. All rights reserved
Practical quantum repeaters with linear optics and double-photon guns
We show how to create practical, efficient, quantum repeaters, employing
double-photon guns, for long-distance optical quantum communication. The guns
create polarization-entangled photon pairs on demand. One such source might be
a semiconducter quantum dot, which has the distinct advantage over parametric
down-conversion that the probability of creating a photon pair is close to one,
while the probability of creating multiple pairs vanishes. The swapping and
purifying components are implemented by polarizing beam splitters and
probabilistic optical CNOT gates.Comment: 4 pages, 4 figures ReVTe
The democratic origins of the term "group analysis": Karl Mannheim's "third way" for psychoanalysis and social science.
It is well known that Foulkes acknowledged Karl Mannheim as the
first to use the term âgroup analysisâ. However, Mannheimâs work is
otherwise not well known. This article examines the foundations of
Mannheimâs sociological interest in groups using the Frankfurt
School (1929â1933) as a start point through to the brief correspondence
of 1945 between Mannheim and Foulkes (previously
unpublished). It is argued that there is close conjunction between
Mannheimâs and Foulkesâs revision of clinical psychoanalysis along
sociological lines. Current renderings of the Frankfurt School
tradition pay almost exclusive attention to the American connection
(Herbert Marcuse, Eric Fromm, Theodor Adorno and Max Horkheimer)
overlooking the contribution of the English connection through
the work of Mannheim and Foulkes
The spread of epidemic disease on networks
The study of social networks, and in particular the spread of disease on
networks, has attracted considerable recent attention in the physics community.
In this paper, we show that a large class of standard epidemiological models,
the so-called susceptible/infective/removed (SIR) models can be solved exactly
on a wide variety of networks. In addition to the standard but unrealistic case
of fixed infectiveness time and fixed and uncorrelated probability of
transmission between all pairs of individuals, we solve cases in which times
and probabilities are non-uniform and correlated. We also consider one simple
case of an epidemic in a structured population, that of a sexually transmitted
disease in a population divided into men and women. We confirm the correctness
of our exact solutions with numerical simulations of SIR epidemics on networks.Comment: 12 pages, 3 figure
Efimov physics from the functional renormalization group
Few-body physics related to the Efimov effect is discussed using the
functional renormalization group method. After a short review of
renormalization in its modern formulation we apply this formalism to the
description of scattering and bound states in few-body systems of identical
bosons and distinguishable fermions with two and three components. The Efimov
effect leads to a limit cycle in the renormalization group flow. Recently
measured three-body loss rates in an ultracold Fermi gas Li atoms are
explained within this framework. We also discuss briefly the relation to the
many-body physics of the BCS-BEC crossover for two-component fermions and the
formation of a trion phase for the case of three species.Comment: 28 pages, 13 figures, invited contribution to a special issue of
"Few-Body Systems" devoted to Efimov physics, published versio
Gamma-ray Observations Under Bright Moonlight with VERITAS
Imaging atmospheric Cherenkov telescopes (IACTs) are equipped with sensitive
photomultiplier tube (PMT) cameras. Exposure to high levels of background
illumination degrades the efficiency of and potentially destroys these
photo-detectors over time, so IACTs cannot be operated in the same
configuration in the presence of bright moonlight as under dark skies. Since
September 2012, observations have been carried out with the VERITAS IACTs under
bright moonlight (defined as about three times the night-sky-background (NSB)
of a dark extragalactic field, typically occurring when Moon illumination >
35%) in two observing modes, firstly by reducing the voltage applied to the
PMTs and, secondly, with the addition of ultra-violet (UV) bandpass filters to
the cameras. This has allowed observations at up to about 30 times previous NSB
levels (around 80% Moon illumination), resulting in 30% more observing time
between the two modes over the course of a year. These additional observations
have already allowed for the detection of a flare from the 1ES 1727+502 and for
an observing program targeting a measurement of the cosmic-ray positron
fraction. We provide details of these new observing modes and their performance
relative to the standard VERITAS observations
Mapping the Two-Component Atomic Fermi Gas to the Nuclear Shell-Model
The physics of a two-component cold fermi gas is now frequently addressed in
laboratories. Usually this is done for large samples of tens to hundreds of
thousands of particles. However, it is now possible to produce few-body systems
(1-100 particles) in very tight traps where the shell structure of the external
potential becomes important. A system of two-species fermionic cold atoms with
an attractive zero-range interaction is analogous to a simple model of nucleus
in which neutrons and protons interact only through a residual pairing
interaction. In this article, we discuss how the problem of a two-component
atomic fermi gas in a tight external trap can be mapped to the nuclear shell
model so that readily available many-body techniques in nuclear physics, such
as the Shell Model Monte Carlo (SMMC) method, can be directly applied to the
study of these systems. We demonstrate an application of the SMMC method by
estimating the pairing correlations in a small two-component Fermi system with
moderate-to-strong short-range two-body interactions in a three-dimensional
harmonic external trapping potential.Comment: 13 pages, 3 figures. Final versio
The First VERITAS Telescope
The first atmospheric Cherenkov telescope of VERITAS (the Very Energetic
Radiation Imaging Telescope Array System) has been in operation since February
2005. We present here a technical description of the instrument and a summary
of its performance. The calibration methods are described, along with the
results of Monte Carlo simulations of the telescope and comparisons between
real and simulated data. The analysis of TeV -ray observations of the
Crab Nebula, including the reconstructed energy spectrum, is shown to give
results consistent with earlier measurements. The telescope is operating as
expected and has met or exceeded all design specifications.Comment: Accepted by Astroparticle Physic
Measurement of the Charged Multiplicities in b, c and Light Quark Events from Z0 Decays
Average charged multiplicities have been measured separately in , and
light quark () events from decays measured in the SLD experiment.
Impact parameters of charged tracks were used to select enriched samples of
and light quark events, and reconstructed charmed mesons were used to select
quark events. We measured the charged multiplicities:
,
, from
which we derived the differences between the total average charged
multiplicities of or quark events and light quark events: and . We compared
these measurements with those at lower center-of-mass energies and with
perturbative QCD predictions. These combined results are in agreement with the
QCD expectations and disfavor the hypothesis of flavor-independent
fragmentation.Comment: 19 pages LaTex, 4 EPS figures, to appear in Physics Letters
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