556 research outputs found
Validity and worth in the science curriculum: learning school science outside the laboratory
It is widely acknowledged that there are problems with school science in many developed countries of the world. Such problems manifest themselves in a progressive decline in pupil enthusiasm for school science across the secondary age range and the fact that fewer students are choosing to study the physical sciences at higher levels and as careers. Responses to these developments have included proposals to reform the curriculum, pedagogy and the nature of pupil discussion in science lessons. We support such changes but argue from a consideration of the aims of science education that secondary school science is too rooted in the science laboratory; substantially greater use needs to be made of out-of-school sites for the teaching of science. Such usage should result in a school science education that is more valid and more motivating and is better at fulfilling defensible aims of school science education. Our contention is that laboratory-based school science teaching needs to be complemented by out-of-school science learning that draws on the actual world (e.g. through fieldtrips), the presented world (e.g. in science centres, botanic gardens, zoos and science museums) and the virtual worlds that are increasingly available through information and communications technologies (ICT)
Path Signatures for Seizure Forecasting
Forecasting the state of a system from an observed time series is the subject
of research in many domains, such as computational neuroscience. Here, the
prediction of epileptic seizures from brain measurements is an unresolved
problem. There are neither complete models describing underlying brain
dynamics, nor do individual patients exhibit a single seizure onset pattern,
which complicates the development of a `one-size-fits-all' solution. Based on a
longitudinal patient data set, we address the automated discovery and
quantification of statistical features (biomarkers) that can be used to
forecast seizures in a patient-specific way. We use existing and novel feature
extraction algorithms, in particular the path signature, a recent development
in time series analysis. Of particular interest is how this set of complex,
nonlinear features performs compared to simpler, linear features on this task.
Our inference is based on statistical classification algorithms with in-built
subset selection to discern time series with and without an impending seizure
while selecting only a small number of relevant features. This study may be
seen as a step towards a generalisable pattern recognition pipeline for time
series in a broader context
Linking Changes in Epithelial Morphogenesis to Cancer Mutations Using Computational Modeling
Most tumors arise from epithelial tissues, such as mammary glands and lobules, and their initiation is associated with the disruption of a finely defined epithelial architecture. Progression from intraductal to invasive tumors is related to genetic mutations that occur at a subcellular level but manifest themselves as functional and morphological changes at the cellular and tissue scales, respectively. Elevated proliferation and loss of epithelial polarization are the two most noticeable changes in cell phenotypes during this process. As a result, many three-dimensional cultures of tumorigenic clones show highly aberrant morphologies when compared to regular epithelial monolayers enclosing the hollow lumen (acini). In order to shed light on phenotypic changes associated with tumor cells, we applied the bio-mechanical IBCell model of normal epithelial morphogenesis quantitatively matched to data acquired from the non-tumorigenic human mammary cell line, MCF10A. We then used a high-throughput simulation study to reveal how modifications in model parameters influence changes in the simulated architecture. Three parameters have been considered in our study, which define cell sensitivity to proliferative, apoptotic and cell-ECM adhesive cues. By mapping experimental morphologies of four MCF10A-derived cell lines carrying different oncogenic mutations onto the model parameter space, we identified changes in cellular processes potentially underlying structural modifications of these mutants. As a case study, we focused on MCF10A cells expressing an oncogenic mutant HER2-YVMA to quantitatively assess changes in cell doubling time, cell apoptotic rate, and cell sensitivity to ECM accumulation when compared to the parental non-tumorigenic cell line. By mapping in vitro mutant morphologies onto in silico ones we have generated a means of linking the morphological and molecular scales via computational modeling. Thus, IBCell in combination with 3D acini cultures can form a computational/experimental platform for suggesting the relationship between the histopathology of neoplastic lesions and their underlying molecular defects
Identification of Fluorescent Compounds with Non-Specific Binding Property via High Throughput Live Cell Microscopy
10.1371/journal.pone.0028802PLoS ONE71
The Suppressor of AAC2 Lethality SAL1 Modulates Sensitivity of Heterologously Expressed Artemia ADP/ATP Carrier to Bongkrekate in Yeast
The ADP/ATP carrier protein (AAC) expressed in Artemia franciscana is refractory to bongkrekate. We generated two strains of Saccharomyces cerevisiae where AAC1 and AAC3 were inactivated and the AAC2 isoform was replaced with Artemia AAC containing a hemagglutinin tag (ArAAC-HA). In one of the strains the suppressor of ÎAAC2 lethality, SAL1, was also inactivated but a plasmid coding for yeast AAC2 was included, because the ArAACÎsal1Î strain was lethal. In both strains ArAAC-HA was expressed and correctly localized to the mitochondria. Peptide sequencing of ArAAC expressed in Artemia and that expressed in the modified yeasts revealed identical amino acid sequences. The isolated mitochondria from both modified strains developed 85% of the membrane potential attained by mitochondria of control strains, and addition of ADP yielded bongkrekate-sensitive depolarizations implying acquired sensitivity of ArAAC-mediated adenine nucleotide exchange to this poison, independent from SAL1. However, growth of ArAAC-expressing yeasts in glycerol-containing media was arrested by bongkrekate only in the presence of SAL1. We conclude that the mitochondrial environment of yeasts relying on respiratory growth conferred sensitivity of ArAAC to bongkrekate in a SAL1-dependent manner. © 2013 Wysocka-Kapcinska et al
Wide-Field InfrarRed Survey Telescope-Astrophysics Focused Telescope Assets WFIRST-AFTA 2015 Report
This report describes the 2014 study by the Science Definition Team (SDT) of
the Wide-Field Infrared Survey Telescope (WFIRST) mission. It is a space
observatory that will address the most compelling scientific problems in dark
energy, exoplanets and general astrophysics using a 2.4-m telescope with a
wide-field infrared instrument and an optical coronagraph. The Astro2010
Decadal Survey recommended a Wide Field Infrared Survey Telescope as its top
priority for a new large space mission. As conceived by the decadal survey,
WFIRST would carry out a dark energy science program, a microlensing program to
determine the demographics of exoplanets, and a general observing program
utilizing its ultra wide field. In October 2012, NASA chartered a Science
Definition Team (SDT) to produce, in collaboration with the WFIRST Study Office
at GSFC and the Program Office at JPL, a Design Reference Mission (DRM) for an
implementation of WFIRST using one of the 2.4-m, Hubble-quality telescope
assemblies recently made available to NASA. This DRM builds on the work of the
earlier WFIRST SDT, reported by Green et al. (2012) and the previous WFIRST-2.4
DRM, reported by Spergel et. (2013). The 2.4-m primary mirror enables a mission
with greater sensitivity and higher angular resolution than the 1.3-m and 1.1-m
designs considered previously, increasing both the science return of the
primary surveys and the capabilities of WFIRST as a Guest Observer facility.
The addition of an on-axis coronagraphic instrument to the baseline design
enables imaging and spectroscopic studies of planets around nearby stars.Comment: This report describes the 2014 study by the Science Definition Team
of the Wide-Field Infrared Survey Telescope mission. 319 pages; corrected a
misspelled name in the authors list and a typo in the abstrac
Perinatal mental ill health - the experiences of women from ethnic minority groups
This study aimed to investigate ethnic minority womenâs experiences and opinions of perinatal mental health problems and the provision of perinatal mental health support services. An exploratory survey was undertaken using a questionnaire. Quantitative data were analysed using descriptive statistics and a simple thematic analysis was used for the qualitative data. A total of 51 responses from women of 14 different ethnic minority backgrounds were analysed. Women from minority ethnic groups face barriers to seeking help for perinatal mental ill health as a result of ongoing stigma and the poor attitudes and behaviours of health professionals and inappropriately designed services. Future interventions should focus on providing adequate cultural competency for health care professionals and ensure that all women are able to access culturally appropriate spaces to talk and be listened to within community settings and wider services
Growth Performance, Carcass Yield, and Quality and Chemical Traits of Meat from Commercial Korean Native Ducks with 2-Way Crossbreeding
This work was conducted to investigate the performance and meat characteristics of commercial Korean native duck (KND). A total of 180 1-d-old ducklings of 2-way crossbreds from A and B lines (from National Institute of Animal Science) were used in this work and divided into 4 groups (3 replicates/group, 15 birds/replicate). The four groups were 4 crossbreds as AA (A line [â]ĂA line [â]), AB (A line [â]ĂB line [â]), BB (Pure line B strains) and BA (B strains [â]ĂA strain [â]). Ducks were fed diets based on corn-soybean meal for 0 to 3 wk (22.4% crude protein [CP], 2,945 kcal/kg metabolizable energy [ME]) and 3 to 8 wk (18.4% CP, 3,047 kcal/kg ME). As a result of this study, average body weight of 4 crossbreds were 625, 1,617, 2,466, and 2,836 g at 2, 4, 6, and 8 weeks, respectively, and significantly increased over the period of time (p<0.05). Body weight of BB group was greater than other crossbreds at the age of 6 weeks (p<0.05). There was a significant difference in weekly body weight gains (p<0.05), which were 573, 991, 850, and 371 g at 2, 4, 6, and 8 weeks old, respectively. Uniformity of 4 crossbreds was 84.9%, 80.5%, and 72.5% at 6, 7, and 8 weeks, respectively, and there was no difference among crossbreds. Body weight gain of BB crossbred was highest among crossbreds (p<0.05). Weekly feed intake significantly increased with weeks as 669, 1,839, 2,812, and 3,381 g at 2, 4, 6, and 8 weeks respectively (p<0.05). Feed intakes of AA and BB crossbreds were higher at 2 to 4 weeks old than others and that of BB crossbred was highest at 4 to 6 weeks old (p<0.05). Weekly feed conversion ratios were 1.17, 1.86, 3.32, and 9.37 at 0 to 2, 2 to 4, 4 to 6, and 6 to 8 weeks old, respectively, and it increased with age (p<0.05). There was no significant difference in feed conversion ratio among crossbreds. Carcass yields of 4 crossbreds were 73.6%, 71.6%, 73.5%, and 71.7%, respectively, so there was no significant difference among crossbreds. There was no difference in wing, neck, breast and leg ratios among crossbreds. However, back ratios of 4 crossbreds were 17.6%, 18.0%, 15.8%, and 17.6%, respectively, and back ratio of BB was the highest among crossbreds. Finally, these results may provide the basic data on the production, carcass quality, fatty acid and amino acid composition of commercial KND with 2-way crossbreeding
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