1,105 research outputs found
Teachers' understanding and operationalisation of 'science capital'
Across the globe, governments, industry and educationalists are in agreement that more needs to be done to increase and broaden participation in post-16 science. Schools, and teachers, are seen as key in this effort. Previous research has found that engagement with science, inclination to study science, and understanding of the value of science strongly relates to a studentâs science capital.
This paper reports on findings from the pilot year of a one-year professional development (PD) programme designed to work with secondary school teachers to build students' science capital. The PD programme introduced teachers to the nature and importance of science capital and thereafter
supported them to develop ways of implementing science capital-building pedagogy in their practice. The data comprises interviews with the participating teachers (n=10), observations of classroom practices, and analyses of the teachers' accounts of their practice. Our findings suggest that teachers found the concept of science capital to be compelling and to resonate with their own intuitive
understandings and experiences. However, the ways in which the concept was operationalised in terms of the implementation of pedagogical practices varied. The difficulties inherent in the operationalisation are examined and recommendations for future work with teachers around the
concept of science capital are developed
Recommended from our members
Fortification and health: challenges and opportunities.
Fortification is the process of adding nutrients or non-nutrient bioactive components to edible products (e.g., food, food constituents, or supplements). Fortification can be used to correct or prevent widespread nutrient intake shortfalls and associated deficiencies, to balance the total nutrient profile of a diet, to restore nutrients lost in processing, or to appeal to consumers looking to supplement their diet. Food fortification could be considered as a public health strategy to enhance nutrient intakes of a population. Over the past century, fortification has been effective at reducing the risk of nutrient deficiency diseases such as beriberi, goiter, pellagra, and rickets. However, the world today is very different from when fortification emerged in the 1920s. Although early fortification programs were designed to eliminate deficiency diseases, current fortification programs are based on low dietary intakes rather than a diagnosable condition. Moving forward, we must be diligent in our approach to achieving effective and responsible fortification practices and policies, including responsible marketing of fortified products. Fortification must be applied prudently, its effects monitored diligently, and the public informed effectively about its benefits through consumer education efforts. Clear lines of authority for establishing fortification guidelines should be developed and should take into account changing population demographics, changes in the food supply, and advances in technology. This article is a summary of a symposium presented at the ASN Scientific Sessions and Annual Meeting at Experimental Biology 2014 on current issues involving fortification focusing primarily on the United States and Canada and recommendations for the development of responsible fortification practices to ensure their safety and effectiveness
An investigation into the sample preparation procedure and analysis of cyanoacrylate adhesives using capillary electrophoresis
In this study, the trace acid profile of cyanoacrylate adhesives was studied using capillary electrophoresis. Liquidâliquid extraction was employed as the sample preparation step before separation by capillary electrophoresis. The solubility of the adhesives was investigated using various organic solvents, e.g. hexane and dichloromethane, and chloroform was determined to be the optimum solvent as it enabled the full dissolution of the adhesive. A comprehensive stability study was performed over a 3-year period and results indicate that the adhesives were stable for 2 years after which their stability and performance degraded
From Flavour to SUSY Flavour Models
If supersymmetry (SUSY) will be discovered, successful models of flavour not
only have to provide an explanation of the flavour structure of the Standard
Model fermions, but also of the flavour structure of their scalar
superpartners. We discuss aspects of such "SUSY flavour" models, towards
predicting both flavour structures, in the context of supergravity (SUGRA). We
point out the importance of carefully taking into account SUSY-specific
effects, such as 1-loop SUSY threshold corrections and canonical normalization,
when fitting the model to the data for fermion masses and mixings. This
entangles the flavour model with the SUSY parameters and leads to interesting
predictions for the sparticle spectrum. We demonstrate these effects by
analyzing an example class of flavour models in the framework of an SU(5) Grand
Unified Theory with a family symmetry with real triplet representations. For
flavour violation through the SUSY soft breaking terms, the class of models
realizes a scheme we refer to as "Trilinear Dominance", where flavour violation
effects are dominantly induced by the trilinear terms.Comment: 44 pages, 10 figures, version published in Nuclear Physics
Molecular Gas in NUclei of GAlaxies (NUGA) XIV. The barred LINER/Seyfert 2 galaxy NGC 3627
We present CO(1-0) and CO(2-1) maps of the interacting barred LINER/Seyfert 2
galaxy NGC 3627 obtained with the IRAM interferometer at resolutions of 2.1" x
1.3" and 0.9" x 0.6", respectively. The molecular gas emission shows a nuclear
peak, an elongated bar-like structure of ~18" (~900 pc) diameter in both CO
maps and, in CO(1-0), a two-arm spiral feature from r~9" (~450 pc) to r~16"
(~800 pc). The inner ~18" bar-like structure, with a north/south orientation
(PA = 14{\deg}), forms two peaks at the extremes of this elongated emission
region. The kinematics of the inner molecular gas shows signatures of
non-circular motions associated both with the 18" bar-like structure and the
spiral feature detected beyond it. The 1.6 micron H-band 2MASS image of NGC
3627 shows a stellar bar with a PA = -21{\deg}, different from the PA (=
14{\deg}) of the CO bar-like structure, indicating that the gas is leading the
stellar bar. The torques computed with the HST-NICMOS F160W image and our PdBI
maps are negative down to the resolution limit of our images, ~60 pc in
CO(2-1). If the bar ends at ~3 kpc, coincident with corotation (CR), the
torques are negative between the CR of the bar and the nucleus, down to the
resolution limit of our observations. This scenario is compatible with a
recently-formed rapidly rotating bar which has had insufficient time to slow
down because of secular evolution, and thus has not yet formed an inner
Lindblad resonance (ILR). The presence of molecular gas inside the CR of the
primary bar, where we expect that the ILR will form, makes NGC 3627 a potential
smoking gun of inner gas inflow. The gas is fueling the central region, and in
a second step could fuel directly the active nucleus.Comment: 24 pages, 28 figures, 2 tables. Accepted for publication in Astronomy
and Astrophysic
Newly Identified Star Clusters in M33. III. Structural Parameters
We present the morphological properties of 161 star clusters in M33 using the
Advanced Camera For Surveys Wide Field Channel onboard the Hubble Space
Telescope using observations with the F606W and F814W filters. We obtain, for
the first time, ellipticities, position angles, and surface brightness profiles
for a significant number of clusters. On average, M33 clusters are more
flattened than those of the Milky Way and M31, and more similar to clusters in
the Small Magellanic Cloud. The ellipticities do not show any correlation with
age or mass, suggesting that rotation is not the main cause of elongation in
the M33 clusters. The position angles of the clusters show a bimodality with a
strong peak perpendicular to the position angle of the galaxy major axis. These
results support the notion that tidal forces are the reason for the cluster
flattening. We fit King and EFF models to the surface brightness profiles and
derive structural parameters including core radii, concentration, half-light
radii and central surface brightness for both filters. The surface brightness
profiles of a significant number of clusters show irregularities such as bumps
and dips. Young clusters (Log age < 8) are notably better fitted by models with
no radial truncation (EFF models), while older clusters show no significant
differences between King or EFF fits. M33 star clusters seem to have smaller
sizes, smaller concentrations, and smaller central surface brightness as
compared to clusters in the MW, M31, LMC and SMC. Analysis of the structural
parameters presents a age-radius relation also detected in other star cluster
systems. The overall analysis shows differences in the structural evolution
between the M33 cluster system and cluster systems in nearby galaxies. These
differences could have been caused by the strong differences in these various
environments.Comment: 30 pages, 12 figures, accepted for publication in MNRA
Longitudinal Assessment of Cortical Excitability in Children and Adolescents With Mild Traumatic Brain Injury and Persistent Post-concussive Symptoms
Introduction: Symptoms following a mild traumatic brain injury (mTBI) usually resolve quickly but may persist past 3 months in up to 15% of children. Mechanisms of mTBI recovery are poorly understood, but may involve alterations in cortical neurophysiology. Transcranial Magnetic Stimulation (TMS) can non-invasively investigate such mechanisms, but the time course of neurophysiological changes in mTBI are unknown.Objective/Hypothesis: To determine the relationship between persistent post-concussive symptoms (PPCS) and altered motor cortex neurophysiology over time.Methods: This was a prospective, longitudinal, controlled cohort study comparing children (8â18 years) with mTBI (symptomatic vs. asymptomatic) groups to controls. Cortical excitability was measured using TMS paradigms at 1 and 2 months post injury. The primary outcome was the cortical silent period (cSP). Secondary outcomes included short interval intracortical inhibition (SICI) and facilitation (SICF), and long-interval cortical inhibition (LICI). Generalized linear mixed model analyses were used to evaluate the effect of group and time on neurophysiological parameters.Results: One hundred seven participants (median age 15.1, 57% female) including 78 (73%) with symptomatic PPCS and 29 with asymptomatic mTBI, were compared to 26 controls. Cortical inhibition (cSP and SICI) was reduced in the symptomatic group compared to asymptomatic group and tended to increase over time. Measures of cortical facilitation (SICF and ICF) were increased in the asymptomatic group and decreased over time. TMS was well tolerated with no serious adverse events.Conclusions: TMS-assessed cortical excitability is altered in children following mild TBI and is dependent on recovery trajectory. Our findings support delayed return to contact sports in children even where clinical symptoms have resolved
The structure and evolution of quasi-stars
The existence of bright quasars at high redshifts implies that supermassive
black holes were able to form in the early Universe. Though a number of
mechanisms to achieve this have been proposed, none yet stands out. A recent
suggestion is the formation of quasi-stars, initially stellar-mass black holes
accreting from hydrostatic giant-like envelopes of gas, formed from the
monolithic collapse of pre-galactic gas clouds. In this work, we modify the
Cambridge STARS stellar evolution package to construct detailed models of the
evolution of these objects. We find that, in all of our models, the black hole
inside the envelope is able to reach slightly more than one-tenth of the total
mass of the system before hydrostatic equilibrium breaks down. This breakdown
occurs after a few million years of evolution. We show that the mechanism which
causes the hydrostatic evolution to end is present in polytropic models. We
also show that the solutions are highly sensitive to the size of the inner
boundary radius and that no physical solutions exist if the inner boundary is
chosen to be less than about 0.3 of the Bondi radius.Comment: 12 pages, 11 figures. Published in MNRAS. Very belatedly updated to
(more closely) match published versio
The UK Infrared Telescope M33 monitoring project. II. The star formation history in the central square kiloparsec
We have conducted a near-infrared monitoring campaign at the UK InfraRed
Telescope (UKIRT), of the Local Group spiral galaxy M33 (Triangulum). The main
aim was to identify stars in the very final stage of their evolution, and for
which the luminosity is more directly related to the birth mass than the more
numerous less-evolved giant stars that continue to increase in luminosity. In
this second paper of the series, we construct the birth mass function and hence
derive the star formation history. The star formation rate has varied between
~0.002 and 0.007 M yr^-1 kpc^-2. We give evidence of two epochs of a
star formation rate enhanced by a factor of a few -- one that happened \geq 6
Gyr ago and produced \geq 80% of the total mass in stars, and one around 250
Myr ago that lasted ~ 200 Myr and formed \leq 6% of the mass in stars. We
construct radial and azimuthal distributions in the image plane and in the
galaxy plane for populations associated with old first-ascent red giant branch
(RGB) stars, intermediate-age Asymptotic Giant Branch (AGB) stars and young
(massive) blue and red supergiants. We find that the RGB stars follow a
spheroidal distribution, while younger stars follow a flat-disc distribution.
The intermediate-age population displays signs of a pseudo-bulge or possibly a
bar. The inner spiral arm pattern as recorded in mid-19^th-century drawings is
confirmed. We interpret our findings as evidence for an old, pressure-supported
component and a younger disc formed 6 Gyr ago, with an accretion event
occurring 250 Myr ago giving rise to the compact nucleus in M33. Our study
provides support for recent Padova stellar evolution models except that
super-AGB stars likely reach low temperatures and thus high mass-loss rates,
supporting the super-AGB nature of the progenitors of dust-enshrouded
supernovae such as SN2008S.Comment: Accepted for publication in MNRA
- âŠ