344 research outputs found
Trajectory Discrimination and Peripersonal Space Perception in Newborns
The ability to discriminate the trajectories of moving objects is highly adaptive and fundamental for physical and social interactions. Therefore, we could reasonably expect sensitivity to different trajectories already at birth, as a precursor of later communicative and defensive abilities. To investigate this possibility, we measured newborns' looking behavior to evaluate their ability to discriminate between visual stimuli depicting motion along different trajectories happening within the space surrounding their body. Differently from previous studies, we did not take into account defensive reactions, which may not be elicited by impending collision as newborns might not categorize approaching stimuli as possible dangers. In two experiments, we showed that newborns display a spontaneous visual preference for trajectories directed toward their body. We found this visual preference when visual stimuli depicted motion in opposite directions (approaching vs. receding) as well as when they both moved toward the peripersonal space and differed only in their specific target (i.e., the body vs. the space around it). These findings suggest that at birth human infants seem to be already equipped with visual mechanisms predisposing them to perceive their presence in the environment and to adaptively focus their attention on the peripersonal space and their bodily self
Molecular basis of oocyte-paracrine signalling that promotes granulosa cell proliferation
Copyright © 2006 Company of BiologistsOocytes regulate follicle growth by secreting paracrine growth factors that act on neighbouring granulosa cells (GCs). Those factors identified to date are mainly members of the transforming growth factor-ß (TGFß) superfamily, but little is known about which specific receptor/signalling system(s) they employ. This study was conducted to determine the requisite pathways utilised by oocytes to promote GC proliferation. We used an established oocyte-secreted mitogen bioassay, where denuded mouse oocytes are co-cultured with mural GCs. Oocytes, growth differentiation factor-9 (GDF9), TGFß1 and activin-A all promoted GC DNA synthesis, but bone-morphogenetic protein 6 (BMP6) did not. Subsequently, we tested the capacity of various TGFß superfamily receptor ectodomains (ECD) to neutralise oocyte- or specific growth factor-stimulated GC proliferation. The BMP type-II receptor (BMPR-II) ECD antagonised oocyte and GDF9 bioactivity dose-dependently, but had no or minimal effect on TGFß1 and activin-A bioactivity, demonstrating its specificity. The TGFßR-II, activinR-IIA and activinR-IIB ECDs all failed to neutralise oocyte- or GDF9-stimulated GC DNA synthesis, whereas they did antagonise the activity of their respective native ligands. An activin receptor-like kinase (ALK) 4/5/7 inhibitor, SB431542, also antagonised both oocyte and GDF9 bioactivity in a dose-dependent manner. Consistent with these findings, oocytes, GDF9 and TGFß1 all activated SMAD2/3 reporter constructs in transfected GC, and led to phosphorylation of SMAD2 proteins in treated cells. Surprisingly, oocytes did not activate the SMAD1/5/8 pathway in transfected GCs although exogenous BMP6 did. This study indicates that oocyte paracrine factors primarily utilise a similar signalling pathway first identified for GDF9 that employs an unusual combination of TGFß superfamily receptors, the BMPR-II and a SMAD2/3 stimulatory ALK (4, 5 or 7), for transmitting their mitogenic actions in GC. This cell-signalling pathway may also have relevance in the hypothalamic-pituitary axis and in germ-somatic cell interactions in the testis.Robert B. Gilchrist, Lesley J. Ritter, Samu Myllymaa, Noora Kaivo-Oja, Rebecca A. Dragovic, Theresa E. Hickey, Olli Ritvos and David G. Mottershea
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Characterizing Communal Creativity in Instrumental Group Learning
Situated broadly within the field of secondary (high) school education, and with a specific focus on the subject area (and extra-curricular educational setting) of instrumental music education, this essay provides evidence of the meaning of communal creativity as it arises in three interrelated practices: creative learning practice, creative teaching practice, and creative teacher leadership practice. This article reports on how learning is enhanced by experiences of communal creativity as illustrated in the case of a particular instrumental ensemble called Percussion 1. Findings support the specific nature of communal creativity, expressed in terms of embodiment, immersion, enhancement, and empowerment, and constituted socially (made manifest in a social context) through activity. Communal creativity has the potential to transform the experience of instrumental group learning with regard to the pedagogical values that aim to engage the whole community of learners
Color Confinement, Quark Pair Creation and Dynamical Chiral-Symmetry Breaking in the Dual Ginzburg-Landau Theory
We study the color confinement, the - pair creation and the
dynamical chiral-symmetry breaking of nonperturbative QCD by using the dual
Ginzburg-Landau theory, where QCD-monopole condensation plays an essential role
on the nonperturbative dynamics in the infrared region. As a result of the dual
Meissner effect, the linear static quark potential, which characterizes the
quark confinement, is obtained in the long distance within the quenched
approximation. We obtain a simple expression for the string tension similar to
the energy per unit length of a vortex in the superconductivity physics. The
dynamical effect of light quarks on the quark confining potential is
investigated in terms of the infrared screening effect due to the -
pair creation or the cut of the hadronic string. The screening length of the
potential is estimated by using the Schwinger formula for the - pair
creation. We introduce the corresponding infrared cutoff to the strong
long-range correlation factor in the gluon propagator as a dynamical effect of
light quarks, and obtain a compact formula of the quark potential including the
screening effect in the infrared region. We investigate the dynamical
chiral-symmetry breaking by using the Schwinger-Dyson equation, where the gluon
propagator includes the nonperturbative effect related toComment: 37 pages, plain TeX (using `phyzzx' macro), (( 8 figures - available
on request from [email protected] )
On Nonperturbative Calculations in Quantum Electrodynamics
A new approach to nonperturbative calculations in quantum electrodynamics is
proposed. The approach is based on a regular iteration scheme for solution of
Schwinger-Dyson equations for generating functional of Green functions. The
approach allows one to take into account the gauge invariance conditions (Ward
identities) and to perform the renormalization program. The iteration scheme
can be realized in two versions. The first one ("perturbative vacuum")
corresponds to chain summation in the diagram language. In this version in
four-dimensional theory the non-physical singularity (Landau pole) arises which
leads to the triviality of the renormalized theory. The second version
("nonperturbative vacuum") corresponds to ladder summation and permits one to
make non-perturbative calculations of physical quantities in spite of the
triviality problem. For chiral-symmetrical leading approximation two terms of
the expansion of the first-step vertex function over photon momentum are
calculated. A formula for anomalous magnetic moment is obtained. A problem of
dynamical chiral symmetry breaking (DCSB) is considered, the calculations are
performed for renormalized theory in Minkowsky space. In the strong coupling
region DCSB-solutions arise. For the renormalized theory a DCSB-solution is
also possible in the weak coupling region but with a subsidiary condition on
the value of .Comment: 31 pages, Plain LaTex, no figures. Journal version: some discussion
and refs. are adde
Voicing the professional doctorate and the researching professional's identity: Theorizing the EdD's uniqueness
Although there is increasing interest in how learning to become a researching professional is understood by students undertaking a professional doctorate of education (EdD), the topic remains under-researched and under-theorized. In this article, we provide a set of theorizations, starting with the purpose and distinctiveness of the professional doctorate and the researching professional identity as this is understood by students and staff participating in the EdD programme in one university in the United Kingdom (UK). This is followed by a retheorization of the researching professional as they develop a reflexive disposition to connect the workplace and the university as the subject and object of the same critical stance. We explore: how the professional doctorate may be understood as practices of diverse researching professionals at different phases and stages of their doctoral journey; the imperative of critical reflexivity as one moves from practitioner to researching professional; and the placing of 'practice' at the nexus of the workplace, the university (doctoral programme) and leading professional change. We conclude with a merging of theorizations building on the being and doing of reflexive practice by EdD doctoral educators/supervisors and doctoral students/researching professionals. Our theorizations are drawn from insights arising from recent EdD research projects (Burnard et al., 2016; Burnard et al., 2018; Heaton et al., forthcoming), and highlighted by narratives from two EdD students currently on a part-time EdD programme
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Collaborative creativity in instrumental group music learning as a site for enhancing pupil wellbeing
This study explores the nature of the elements that co-influence collaborative creativity in instrumental group music learning and the intrinsic potential for enhancing pupil wellbeing as evidenced in a particular secondary-school (extra-curricular) group instrumental programme Percussion 1. Wenger's Community of Practice (CoP) and Engestrom's Activity Theory (AT) provide an in-depth analytical framework for the analysis of 14 rehearsals, 13 semi-structured interviews and 41 teachers' and pupils' reflective diary entries. Findings support the intrinsic potential for enhancing pupil wellbeing by empowering them through supportive statements and decision-making, and engaging them through the embodiment of music learning
Monoubiquitination of syntaxin 3 leads to retrieval from the basolateral plasma membrane and facilitates cargo recruitment to exosomes
Syntaxin 3 (Stx3), a SNARE protein located and functioning at the apical plasma membrane of epithelial cells, is required for epithelial polarity. A fraction of Stx3 is localized to late endosomes/lysosomes, although how it traffics there and its function in these organelles is unknown. Here we report that Stx3 undergoes monoubiquitination in a conserved polybasic domain. Stx3 present at the basolateral—but not the apical—plasma membrane is rapidly endocytosed, targeted to endosomes, internalized into intraluminal vesicles (ILVs), and excreted in exosomes. A nonubiquitinatable mutant of Stx3 (Stx3-5R) fails to enter this pathway and leads to the inability of the apical exosomal cargo protein GPRC5B to enter the ILV/exosomal pathway. This suggests that ubiquitination of Stx3 leads to removal from the basolateral membrane to achieve apical polarity, that Stx3 plays a role in the recruitment of cargo to exosomes, and that the Stx3-5R mutant acts as a dominant-negative inhibitor. Human cytomegalovirus (HCMV) acquires its membrane in an intracellular compartment and we show that Stx3-5R strongly reduces the number of excreted infectious viral particles. Altogether these results suggest that Stx3 functions in the transport of specific proteins to apical exosomes and that HCMV exploits this pathway for virion excretion
A research-informed, school-based professional development workshop programme to promote dialogic teaching with interactive technologies
The study reported in this article investigated the influence of a researchinformed, school-based, professional development workshop programme on the quality of classroom dialogue using the interactive whiteboard (IWB). The programme aimed to develop a dialogic approach to teaching and learning mediated through more interactive uses of the IWB, through a model of active participation of students, collaborative knowledgebuilding, learning through inquiry and evaluating ideas. Ten professional development workshops based on video-stimulated discussions of practices were co-developed and conducted with an ‘ambassador’ within each of five school clusters. In total, 80 teachers from 15 schools, ranging from infant to secondary schools, participated. Data were collected through surveys, semi-structured interviews with teachers and ambassadors, teachers’ posters created during workshop activities, lesson observations and a portfolio of dialogic classroom practices, mediated by the IWB. Findings strongly support the potential of this ambassador-led workshop model to involve teachers in developing their understandings of classroom dialogue and devising new approaches to support it. The research additionally confirms the potential of the IWB as a tool to support dialogic teaching.This work was supported by the UK Economic and Social Research Council (ESRC) Impact Acceleration Pilot Programme from February-August 2014. It built on previous work carried out as part of a personal Research Fellowship programme of work by Sara Hennessy in 2007-2010 under ESRC Grant RES063270081; the 'IWBs and Dialogic Teaching' project (http://dialogueiwb.educ.cam.ac.uk/) was conducted in collaboration with Neil Mercer and Paul Warwick
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