373 research outputs found
The impact of rural contexts on citizenship education
Social studies teachers are sensitive to local school and community values and, therefore, tactful when making decisions about their curriculum (Romanowski, 1996; Shaver, Davis, & Helburn, 1980; Thornton, 1989), including its citizenship aims (Saada, 2013; Sondel, 2015; Vinson, 1998). For this reason, scholars call for better contextual understandings of teachers\u27 curricular-instructional gatekeeping (Thornton, 1989; Vinson, 1998). Rural-specific examples of this phenomenon remain largely unexamined (Martin & Chiodo, 2007; Pattison-Meek, 2012), though rural schools make up 32.9% of all schools in the United States (Johnson, Showalter, Klein, & Lester, 2014) and rural communities offer distinct socio-geographic and socio-cultural contexts (Brown & Schafft, 2011). To address this research deficit, the current study sampled five government teachers in rural schools to examine their conceptualizations of citizenship education, perceptions of place, and the influences that affect their curricular-instructional gatekeeping. This study adopted a social constructionist perspective to explore the values and meanings participants placed on citizenship within their rural contexts. It utilized a grounded theory research design to sample government teachers from four distant-rural schools and collect data from three sources: interviews, classroom observations, and teaching artifacts. A constant comparison method of data analysis produced a theory to describe citizenship education in rural contexts. The theory consists of three themes that emerged from the data: (1) citizenship education as practical knowledge; (2) place-based learning for future (dis)placements; and (3) the gatekeeping triad. Descriptions of these themes and their relationships with one another illuminate the practices of citizenship education in rural areas and provide knowledge of the rural conditions that influence it. Findings suggest government teachers in rural areas need to become more critical of their treatment of place and citizenship to encourage place-conscious civic life
Teachers’ Perspectives on Global Citizenship Education in Central Appalachia
This paper reports on a sequential mixed-methods (quan à QUAL) study that explored rural Appalachian teachers' perspectives and pedagogical decisions about Global Citizenship Education (GCE). In phase one, a questionnaire was completed by social studies teachers (n=19) from remote and distant rural high schools located in Central Appalachia across two states. Closed-ended items were analyzed through descriptive statistics. Open-ended items were coded to elicit themes that helped to answer the research questions. In phase two, two participants from the original sample were interviewed to uncover their experiences navigating GCE in their unique community contexts. Findings suggest social studies teachers in rural Appalachia, while not using the exact terminology of global citizenship, support multiple types of global citizenship aims. They tend to perceive their communities as homogenous, isolated, and conservative, which presented both challenges to and stimuli for teaching global curricula. Participants tend to perceive much of their global curricula as contrarian in their communities and, therefore, relied on professional tact and community-based knowledge as rural natives to inform their pedagogical decisions
Surface-enhanced Raman spectroscopy in 3D electrospun nanofiber mats coated with gold nanorods
Nanofibers functionalized by metal nanostructures and particles are exploited
as effective flexible substrates for SERS analysis. Their complex
three-dimensional structure may provide Raman signals enhanced by orders of
magnitude compared to untextured surfaces. Understanding the origin of such
improved performances is therefore very important for pushing nanofiber-based
analytical technologies to their upper limit. Here we report on polymer
nanofiber mats which can be exploited as substrates for enhancing the Raman
spectra of adsorbed probe molecules. The increased surface area and the
scattering of light in the nanofibrous system are individually analyzed as
mechanisms to enhance Raman scattering. The deposition of gold nanorods on the
fibers further amplifies Raman signals due to SERS. This study suggests that
Raman signals can be finely tuned in intensity and effectively enhanced in
nanofiber mats and arrays by properly tailoring the architecture, composition,
and light-scattering properties of the complex networks of filaments.Comment: 29 pages, 9 figures, 1 Tabl
Applying Deweyan Principles to Global Citizenship Education in a Rural Context
Abstract Global citizenship education (GCE) helps students conceptualize citizenship beyond national boundaries so they are capable of action in dealing with global issues like human rights and environmental sustainability. However, very little literature exists to assist rural teachers in implementing GCE as they face specific challenges due to the context of their schools. This paper identifies challenges rural educators encounter, such as conservative communities and geographic isolation, and details a Deweyan approach to GCE as a means to overcome these challenges. Specifically, we apply Dewey’s democratic and social learning theories to reconceptualize GCE around student, family, and community life to foster a more relevant curriculum that utilizes students’ experiences (Dewey, 1897, 1902, 1938, 1916/2008). It emphasizes the utmost respect for local customs and culture by using them as sources of content for the curriculum while simultaneously extending citizenship thoughts and actions to the global arena.
Anisotropic conjugated polymer chain conformation tailors the energy migration in nanofibers
Conjugated polymers are complex multi-chromophore systems, with emission
properties strongly dependent on the electronic energy transfer through active
sub-units. Although the packing of the conjugated chains in the solid state is
known to be a key factor to tailor the electronic energy transfer and the
resulting optical properties, most of the current solution-based processing
methods do not allow for effectively controlling the molecular order, thus
making the full unveiling of energy transfer mechanisms very complex. Here we
report on conjugated polymer fibers with tailored internal molecular order,
leading to a significant enhancement of the emission quantum yield. Steady
state and femtosecond time-resolved polarized spectroscopies evidence that
excitation is directed toward those chromophores oriented along the fiber axis,
on a typical timescale of picoseconds. These aligned and more extended
chromophores, resulting from the high stretching rate and electric field
applied during the fiber spinning process, lead to improved emission
properties. Conjugated polymer fibers are relevant to develop optoelectronic
plastic devices with enhanced and anisotropic properties.Comment: 43 pages, 15 figures, 1 table in Journal of the American Chemical
Society, (2016
A last millennium perspective on North Atlantic variability: exploiting synergies between models and proxy data
The North Atlantic is a key region for decadal prediction
as it has experienced significant multi-decadal variability
over the observed period. This variability, which is
thought to be intrinsic to the region, can potentially
modulate, either by amplifying or mitigating, the
global warming signal from anthropogenic greenhouse
emissions. For example, studies suggest that the North
Atlantic contributed to the recent hiatus period between
1998 and 2012, by triggering an atmospheric response
which impacted on the eastern tropical Pacific (e.g.
McGregor et al., 2014). The subpolar North Atlantic is
also a major CO2
sink, and therefore of great importance
for the global carbon cycle (Perez et al., 2013).
One of the key players in the North Atlantic region is the
Atlantic Meridional Overturning Circulation (AMOC),
which is associated with sinking due to deep water
formation in the Labrador and Nordic Seas. The AMOC is
the primary control of the poleward heat transport in the
Atlantic region. Therefore, the AMOC is associated with
important climate impacts, and plays an active role in
various feedback mechanisms with, for example, sea ice
(Mahajan et al., 2011) and the atmospheric circulation
(Gastineau and Frankignoul, 2012). The AMOC has
exhibited abrupt variations in the past (e.g. the last glacial
period, Rahmstorf, 2002) and could experience a major
slowdown in the future due to the combined effect of
surface warming and Greenland ice sheet melting on deep
water formation (Bakker et al., 2016). The possibility
of such a shutdown has stimulated considerable
international efforts to observe and reconstruct the
past AMOC changes. Only by understanding its natural
variability will we be able to detect and anticipate an
anthropogenic impact on the AMOC.
Decadal modulations are also found in other large-scale
modes of climate variability, such as the North Atlantic
Oscillation (NAO) (Stephenson et al., 2000), the Subpolar
Gyre strength (SPG) (Häkkinen and Rhines, 2004) and
the Atlantic Multidecadal Variability (AMV) (Enfield et al.,
2001), which have all been linked with widespread climate
impacts over the surrounding continents. Modelling
studies suggest that all these modes interact with the
AMOC (Gastineau and Frankignoul, 2012; Hátún et al.,
2005; Knight et al., 2005) but the exact interrelationships
are complex and remain to be disentangled. Also to be
determined are the underlying mechanisms responsible
for the decadal and centennial AMOC modulations, with
different climate models showing different key drivers
(Menary et al., 2015a). Similarly, the exact impact of the
natural external forcings (e.g. volcanic aerosols, solar
irradiance) on the variability of these different largescale
climate modes still remains unclear
Control of photon transport properties in nanocomposite nanowires
Active nanowires and nanofibers can be realized by the electric-field induced
stretching of polymer solutions with sufficient molecular entanglements. The
resulting nanomaterials are attracting an increasing attention in view of their
application in a wide variety of fields, including optoelectronics, photonics,
energy harvesting, nanoelectronics, and microelectromechanical systems.
Realizing nanocomposite nanofibers is especially interesting in this respect.
In particular, methods suitable for embedding inorganic nanocrystals in
electrified jets and then in active fiber systems allow for controlling
light-scattering and refractive index properties in the realized fibrous
materials. We here report on the design, realization, and morphological and
spectroscopic characterization of new species of active, composite nanowires
and nanofibers for nanophotonics. We focus on the properties of
light-confinement and photon transport along the nanowire longitudinal axis,
and on how these depend on nanoparticle incorporation. Optical losses
mechanisms and their influence on device design and performances are also
presented and discussed.Comment: 7 pages, 3 figures, 29 references. Invited contribution. Copyright
(2016) Society of Photo Optical Instrumentation Engineers. One print or
electronic copy may be made for personal use only. Systematic reproduction
and distribution, duplication of any material in this paper for a fee or for
commercial purposes, or modification of the content of the paper are
prohibite
Reliability of transcranial magnetic stimulation evoked potentials to detect the effects of theta-burst stimulation of the prefrontal cortex
Background: Transcranial magnetic stimulation (TMS) with simultaneous electroencephalography (EEG) is a novel method for assessing cortical properties outside the motor region. Theta burst stimulation (TBS), a form of repetitive TMS, can non-invasively modulate cortical excitability and has been increasingly used to treat psychiatric disorders by targetting the dorsolateral prefrontal cortex (DLPFC). The TMS-evoked potentials (TEPs) and local mean field power (LMFP) analyses have been used to evaluate local cortical excitability changes after TBS. However, it remains unclear whether TEPs can detect the neuromodulatory effects of TBS. Objectives: To confirm the reliability of TEP components and LMFP within and between sessions and to measure changes in neural excitability induced by intermittent (iTBS) and continuous TBS (cTBS) applied to the left DLPFC. Methods: Test-retest reliability of TEPs/LMFP and TBS-induced changes in cortical excitability were assessed in twenty-four healthy participants by stimulating the DLPFC in five separate sessions, once with sham and twice with iTBS and cTBS. EEG responses were recorded of 100 single TMS pulses before and after TBS, and the reproducibility measures were quantified with the concordance correlation coefficient (CCC). Results: The N100 and P200 components presented substantial reliability within the baseline block (CCCs>0.8) and moderate concordance between sessions (CCCmax> 0.6). Both N40 and P60 TEP amplitudes showed little concordance between sessions. Similar results were achieved using LMFP responses. Changes in TEP amplitudes after iTBS were marginally reliable for N100 (CCCmax = 0.52), P200 (CCCmax = 0.47) and P60 (CCCmax = 0.40), presenting only fair levels of concordance at specific time points. LMFP changes showed poor reproducibility after iTBS and cTBS. Conclusions: The present findings show that only the N100 and P200 components had good concordance between sessions. The reliability of earlier TEP components and LMF responses may have been affected by a sub-optimal removal of TMS-related artefacts. The poor reliability in detecting changes in neural excitability induced by TBS indicates that TEPs/LMFP do not provide a precise estimate of the changes in excitability in the DLPFC or, alternatively, that TBS did not induce consistent changes in neural excitability
Neuromodulatory effects of theta burst stimulation to the prefrontal cortex
Theta burst stimulation (TBS) is a new form of repetitive transcranial magnetic stimulation (TMS) capable of non-invasively modulating cortical excitability. In recent years TBS has been increasingly used as a neuroscientific investigative tool and therapeutic intervention for psychiatric disorders, in which the dorsolateral prefrontal cortex (DLPFC) is often the primary target. However, the neuromodulatory effects of TBS on prefrontal regions remain unclear. Here we share EEG and ECG recordings and structural MRI scans, including high-resolution DTI, from twenty-four healthy participants who received intermittent TBS (two sessions), continuous TBS (two sessions), and sham stimulation (one session) applied to the left DLPFC using a single-blinded crossover design. Each session includes eyes-open resting-state EEG and single-pulse TMS-EEG obtained before TBS and 2−, 15−, and 30-minutes post-stimulation. This dataset enables foundational basic science investigations into the neuromodulatory effects of TBS on the DLPFC
Behavioural and neurophysiological differences in working memory function of depressed patients and healthy controls
Objective: Major depressive disorder (MDD) is associated with deficits in working memory. Several cognitive subprocesses interact to produce working memory, including attention, encoding, maintenance and manipulation. We sought to clarify the contribution of functional deficits in these subprocesses in MDD by varying cognitive load during a working memory task. Methods: 41 depressed participants and 41 age and gender-matched healthy controls performed the n-back working memory task at three levels of difficulty (0-, 1-, and 2-back) in a pregistered study. We assessed response times, accuracy, and event-related electroencephalography (EEG), including P2 and P3 amplitudes, and frontal theta power (4–8 Hz). Results: MDD participants had prolonged response times and more positive frontal P3 amplitudes (i.e., Fz) relative to controls, mainly in the most difficult 2-back condition. Working memory accuracy, P2 amplitudes and frontal theta event-related synchronisation did not differ between groups at any level of task difficulty. Conclusions: Depression is associated with generalized psychomotor slowing of working memory processes, and may involve compensatory hyperactivity in frontal and parietal regions. Significance: These findings provide insights into MDD working memory deficits, indicating that depressed individuals dedicate greater levels of cortical processing and cognitive resources to achieve comparable working memory performance to controls
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