1,070 research outputs found
Children's understanding of inherited resemblance: The case of two parents. [IF 1.0]
Four-, 6-, and 10-year-old children were tested in a forced-choice procedure about their beliefs on the inheritance of physical characteristics. They were presented with pictures of two biological parents, and then asked to select the most likely descendant out of three alternatives: a father look-alike, a mother look-alike, and an alternative representing the combined influence of both parents. In several question pairs, additional information was given about the parent-child relationship that was clearly irrelevant to the principles of heredity to examine the extent to which domain confusions were likely to occur. The majority of the 10-year-olds consistently preferred the alternative in which the combined influence of both parents was shown and domain confusions hardly ever occurred. Four- and 6-year-olds, in contrast, were still influenced by information from alien domains, although even their reasoning about inheritance seemed to be theory-like. Overall, the results suggest that with age, children develop a more restricted and better-defined conception of the principles of heredity, in which the combined influence of both parents is acknowledged
The mediating effect of task presentation on collaboration and children's acquisition of scientific reasoning
There has been considerable research concerning peer interaction and the acquisition of children's scientific reasoning. This study investigated differences in collaborative activity between pairs of children working around a computer with pairs of children working with physical apparatus and related any differences to the development of children's scientific reasoning. Children aged between 9 and 10 years old (48 boys and 48 girls) were placed into either same ability or mixed ability pairs according to their individual, pre-test performance on a scientific reasoning task. These pairs then worked on either a computer version or a physical version of Inhelder and Piaget's (1958) chemical combination task. Type of presentation was found to mediate the nature and type of collaborative activity. The mixed-ability pairs working around the computer talked proportionally more about the task and management of the task; had proportionally more transactive discussions and used the record more productively than children working with the physical apparatus. Type of presentation was also found to mediated children's learning. Children in same ability pairs who worked with the physical apparatus improved significantly more than same ability pairs who worked around the computer. These findings were partially predicted from a socio-cultural theory and show the importance of tools for mediating collaborative activity and collaborative learning
Spatial Light Modulators for the Manipulation of Individual Atoms
We propose a novel dipole trapping scheme using spatial light modulators
(SLM) for the manipulation of individual atoms. The scheme uses a high
numerical aperture microscope to map the intensity distribution of a SLM onto a
cloud of cold atoms. The regions of high intensity act as optical dipole force
traps. With a SLM fast enough to modify the trapping potential in real time,
this technique is well suited for the controlled addressing and manipulation of
arbitrarily selected atoms.Comment: 9 pages, 5 figure
A-dependence of nuclear transparency in quasielastic A(e,e'p) at high Q^2
The A-dependence of the quasielastic A(e,e'p) reaction has been studied at
SLAC with H-2, C, Fe, and Au nuclei at momentum transfers Q^2 = 1, 3, 5, and
6.8 (GeV/c)^2. We extract the nuclear transparency T(A,Q^2), a measure of the
average probability that the struck proton escapes from the nucleus A without
interaction. Several calculations predict a significant increase in T with
momentum transfer, a phenomenon known as Color Transparency. No significant
rise within errors is seen for any of the nuclei studied.Comment: 5 pages incl. 2 figures, Caltech preprint OAP-73
Applying SNP marker technology in the cacao breeding programme in Ghana
In this investigation 45 parental cacao plants and five progeny derived
from the parental stock studied were genotyped using six SNP markers to
determine off-types or mislabeled clones and to authenticate crosses
made in the Cocoa Research Institute of Ghana (CRIG) breeding
programme. Investigation was based on the 5\u2019 nuclease SNPassay
using Illustra Hot Start mix Ready-To-Go PCR strips and BioTek
FLx800TBP Fluorescence Microplate Reader. In a group of six cacao
plants labeled as PA150 clones and another five labeled as Pound7, one
clone in each group was unambiguously determined as off-type or
mislabeled. Similarly, in a cohort of 23 PA7 "clones", four genotypes
were differentiated. Cross-checking the fidelity of five progeny from
the parental stock under study, it was established that no errors were
made in the crossing. The most significant outcome of this study,
however, was that out of the four categories of 23 PA7 candidate
parental trees only one category can be comparable to the reference
clone in the International Cacao Germplasm collection, Trinidad
(ICG,T); thus informing the need for further work to find the correct
clone among these for the breeding programme. It was thus concluded
that thissimple yet cutting-edge genotyping procedure can be used in
applied cocoa breeding programmes in a cocoa producing country. This
work represents a first step in the genotypic characterisation of the
CRIG germplasm collection and Seed Gardens.Au cours de cette recherche, 45 plants de cacao parentaux et 5
descendants d\ue9rivant du stock parental ont \ue9t\ue9
g\ue9notyp\ue9 en utilisant 6 marqueurs SNP, afin de
d\ue9terminer les clones mal \ue9tiquet\ue9s et
d\u2019authentifier les croisements effectu\ue9s dans le programme
d\u2019am\ue9lioration de l\u2019Institut de Recherche sur le Cacao
au Ghana (CRIG). Cette \ue9tude a \ue9t\ue9 bas\ue9e sur les 5'
nucl\ue9ases SNP en utilisant des bandes PCR "Hot Start mix
Ready-To-Go PCR strips" et un Lecteur Microplat \ue0 Fluorescence
"BioTek FLx800TBP". Au sein d\u2019un groupe de six plants de cacao
\ue9tiquet\ue9 PA150 et d\u2019un autre groupe de cinq
\ue9tiquet\ue9 Pound 7, il a \ue9t\ue9 d\ue9termin\ue9 sans
ambigu\ueft\ue9 qu\u2019un clone par groupe \ue9tait mal
\ue9tiquet\ue9. De fa\ue7on similaire, quatre g\ue9notypes
diff\ue9rents ont \ue9t\ue9 identifi\ue9s dans une m\ueame
cohorte de clones 23PA7. En v\ue9rifiant la fid\ue9lit\ue9 de
cinq descendants issus du stock parental \ue9tudi\ue9, il a
\ue9t\ue9 \ue9tabli qu\u2019aucune erreur n\u2019avait
\ue9t\ue9 faite lors du croisement. Le r\ue9sultat le plus
significatif de cette \ue9tude a \ue9t\ue9 que, sur quatre
cat\ue9gories de 23 candidats PA7 de souches parentales, une seule
pouvait \ueatre comparable au clone de r\ue9f\ue9rence dans la
collection Internationale du Germoplasme de Cacao, Trinidad (ICG,T),
d\ue9montrant ainsi la n\ue9cessit\ue9 de travaux
suppl\ue9mentaires pour d\ue9terminer le clone exact parmi ceux
\ue9voqu\ue9s pr\ue9c\ue9demment. Il a ainsi \ue9t\ue9
conclu que cette m\ue9thode avant-gardiste de g\ue9notypage,
pourtantsimple, peut \ueatre utilis\ue9e dans les programmes
appliqu\ue9s d\u2019am\ue9lioration du cacao dans un pays
producteur. Ce travail repr\ue9sente une premi\ue8re \ue9tape
dans la caract\ue9risation g\ue9n\ue9tique de la collection du
germoplasme CRIG et jardins semenciers
Heavy-quark mass dependence in global PDF analyses and 3- and 4-flavour parton distributions
We study the sensitivity of our recent MSTW 2008 NLO and NNLO PDF analyses to
the values of the charm- and bottom-quark masses, and we provide additional
public PDF sets for a wide range of these heavy-quark masses. We quantify the
impact of varying m_c and m_b on the cross sections for W, Z and Higgs
production at the Tevatron and the LHC. We generate 3- and 4-flavour versions
of the (5-flavour) MSTW 2008 PDFs by evolving the input PDFs and alpha_S
determined from fits in the 5-flavour scheme, including the eigenvector PDF
sets necessary for calculation of PDF uncertainties. As an example of their
use, we study the difference in the Z total cross sections at the Tevatron and
LHC in the 4- and 5-flavour schemes. Significant differences are found,
illustrating the need to resum large logarithms in Q^2/m_b^2 by using the
5-flavour scheme. The 4-flavour scheme is still necessary, however, if cuts are
imposed on associated (massive) b-quarks, as is the case for the experimental
measurement of Z b bbar production and similar processes.Comment: 40 pages, 11 figures. Grids can be found at
http://projects.hepforge.org/mstwpdf/ and in LHAPDF V5.8.4. v2: version
published in EPJ
Professionalism, Golf Coaching and a Master of Science Degree: A commentary
As a point of reference I congratulate Simon Jenkins on tackling the issue of professionalism in coaching. As he points out coaching is not a profession, but this does not mean that coaching would not benefit from going through a professionalization process. As things stand I find that the stimulus article unpacks some critically important issues of professionalism, broadly within the context of golf coaching. However, I am not sure enough is made of understanding what professional (golf) coaching actually is nor how the development of a professional golf coach can be facilitated by a Master of Science Degree (M.Sc.). I will focus my commentary on these two issues
Electron Scattering From High-Momentum Neutrons in Deuterium
We report results from an experiment measuring the semi-inclusive reaction
where the proton is moving at a large angle relative to the
momentum transfer. If we assume that the proton was a spectator to the reaction
taking place on the neutron in deuterium, the initial state of that neutron can
be inferred. This method, known as spectator tagging, can be used to study
electron scattering from high-momentum (off-shell) neutrons in deuterium. The
data were taken with a 5.765 GeV electron beam on a deuterium target in
Jefferson Laboratory's Hall B, using the CLAS detector. A reduced cross section
was extracted for different values of final-state missing mass ,
backward proton momentum and momentum transfer . The data
are compared to a simple PWIA spectator model. A strong enhancement in the data
observed at transverse kinematics is not reproduced by the PWIA model. This
enhancement can likely be associated with the contribution of final state
interactions (FSI) that were not incorporated into the model. A ``bound neutron
structure function'' was extracted as a function of and
the scaling variable at extreme backward kinematics, where effects of
FSI appear to be smaller. For MeV/c, where the neutron is far
off-shell, the model overestimates the value of in the region of
between 0.25 and 0.6. A modification of the bound neutron structure
function is one of possible effects that can cause the observed deviation.Comment: 33 pages RevTeX, 9 figures, to be submitted to Phys. Rev. C. Fixed 1
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