This paper explores the most efficient teaching context to learn words’ visual aspects and by second-grade French-speaking children, including those with special needs. Students came from six ...classrooms and each classroom was randomly assigned to the control group or to one of two experimental interventions (TFS: explicit teaching of semantic and formal properties of words; TF: explicit teaching of formal properties of words). For students without difficulties, the experimental interventions have contributed equally to the learning of the words’ visual aspect, whereas no progress was observed for the control group. For students with special needs, only the intervention that combined explicit instruction of semantic and formal properties lead to significant progress. These results suggest that explicit instruction should focus on the semantic and formal properties of words, especially for students with special needs.
Let
k
be a field of characteristic zero and
B
a commutative integral domain that is also a finitely generated
k
-algebra. It is well known that if
k
is algebraically closed and the “field ...Makar-Limanov” invariant FML(
B
) is equal to
k
, then
B
is unirational over
k
. This article shows that, when
k
is not assumed to be algebraically closed, the condition FML(
B
) =
k
implies that there exists a nonempty Zariski-open subset
U
of Spec
B
with the following property: for each prime ideal
p
∈
U
, the κ(
p
)-algebra κ(
p
)⊗
k
B
can be embedded in a polynomial ring in
n
variables over κ(
p
), where
n
= dim
B
and κ(
p
) =
B
p
/
p
B
p
.
Let
B
be a commutative
ℤ
-graded domain of characteristic zero. An element
f
of
B
is said to be
cylindrical
if it is nonzero, homogeneous of nonzero degree, and such that
B
(
f
)
is a polynomial ring ...in one variable over a subring. We study the relation between the existence of a cylindrical element of
B
and the existence of a nonzero locally nilpotent derivation of
B
. Also, given
d
≥ 1, we give sufficient conditions that guarantee that every derivation of
B
(
d
)
=
⊕
i
∈
ℤ
B
d
i
can be extended to a derivation of
B
. We generalize some results of Kishimoto, Prokhorov and Zaidenberg that relate the cylindricity of a polarized projective variety (
Y
,
H
) to the existence of a nontrivial
G
a
-action on the affine cone over (
Y
,
H
).
Fix a field k of characteristic zero. If a1,…,an (n≥3) are positive integers, the integral domainBa1,…,an=kX1,…,Xn/〈X1a1+⋯+Xnan〉 is called a Pham-Brieskorn ring. It is conjectured that if ai≥2 for ...all i and ai=2 for at most one i, then Ba1,…,an is rigid. (A ring B is said to be rigid if the only locally nilpotent derivation D:B→B is the zero derivation.) The conjecture is known to be true when n=3, and in certain special cases when n≥4. This article settles several cases not covered by previous results. For instance, we show that if a≥n≥4 then Ba,…,a is rigid (where ‘a’ occurs n times), and that if ∑i=1n1ai≤1n−2 then Ba1,…,an is stably rigid.
We strengthen certain results concerning actions of
$\left( \mathbb{C},\,+ \right)$
on
${{\mathbb{C}}^{3}}$
and embeddings of
${{\mathbb{C}}^{2}}$
in
${{\mathbb{C}}^{3}}$
, and show that these ...results are in fact valid over any field of characteristic zero.
We give several criteria for a ring to be a UFD, including generalizations of some criteria due to P. Samuel. These criteria are applied to construct, for any field k, (1) a Z-graded non-noetherian ...rational UFD of dimension 3 over k, and (2) k-affine rational UFDs defined by trinomial relations.
Two precise goals were targeted in this research: 1) Describing the orthographical knowledge of the student with a DLD (Developmental Language Disorder) and 2) identify if the written word production ...results are related to other tests using orthographical knowledge such as word/pseudoword recognition. A group comparative methodological approach was used in this study in order to analyze the results of three groups of participants of the study sample: 1) An experimental group including students with severe DLD (TDL, n = 25, M age = 9.72); 2) a controlled group matched according to reading skill level (CL, n = 26, M age = 8.22); and 3) a controlled group matched according to chronological age (CA, n = 42, M age = 9.82). This exploratory study's results suggest that the performances in orthographical production of students who have a DLD are similar to those of the younger students (CL). Lastly, significant correlation links between the performance of reading and production word tasks were identified in the three groups of participants.
Notre étude poursuivait deux objectifs : 1) décrire les connaissances orthographiques des élèves ayant un trouble développemental du langage (TDL) et 2) identifier si les scores en production ...orthographique sont reliés à d’autres épreuves ayant recours aux connaissances orthographiques, comme la reconnaissance de mots et de pseudomots, et la compréhension en lecture. Une approche méthodologique à groupes comparatifs a été employée pour analyser les performances de trois groupes de participants : 1) un groupe expérimental incluant des élèves francophones du primaire présentant un TDL sévère (TDL, n = 25, âge chronologique moyen = 9.72) ; 2) un groupe contrôle de niveau de lecture (CL, n = 26, âge chronologique moyen = 8.22) ; et 3) un groupe contrôle de même âge chronologique (CA, n = 42, âge chronologique moyen = 9.82). Les résultats indiquent que les performances en production orthographique des élèves ayant un TDL s’apparentent à celles des élèves du groupe CL. Enfin, des liens significatifs de corrélation entre les performances en lecture et en production orthographique ont été identifiés dans les trois groupes de participants.
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