Pointed Trees Of Projective Spaces

We introduce a smooth projective variety T(d,n) which compactifies the space of configurations of it distinct points oil affine d-space modulo translation and homothety. The points in the boundary correspond to n-pointed stable rooted trees of d-dimensional projective spaces, which for d = 1, are (n + 1)-pointed stable rational curves. In particular, T(1,n) is isomorphic to ($) over bar (0,n+1), the moduli space of such curves. The variety T(d,n) shares many properties with (M) over bar (0,n+1). For example, as we prove, the boundary is a smooth normal crossings divisor whose components are products of T(d,i) for i \u3c n and it has an inductive construction analogous to but differing from Keel\u27s for (0,n+1). This call be used to describe its Chow groups and Chow motive generalizing [Trans. Airier. Math. Soc. 330 (1992), 545-574]. It also allows us to compute its Poincare polynomials, giving all alternative to the description implicit in [Progr. Math., vol. 129, Birkhauser, 1995, pp. 401-417]. We give a presentation of the Chow rings of T(d,n), exhibit explicit dual bases for the dimension I and codimension 1 cycles. The variety T(d,n) is embedded in the Fulton-MacPherson spaces X[n] for any smooth variety X, and we use this connection in a number of ways. In particular we give a family of ample divisors on T(d,n) and an inductive presentation of the Chow motive of X[n]. This also gives an inductive presentation of the Chow groups of X[n] analogous to Keel\u27s presentation for (M) over bar (0,n+1), solving a problem posed by Fulton and MacPherson

COMMENTARY: CAN FREE READING TAKE YOU ALL THE WAY? A RESPONSE TO COBB (2007)

Cobb (2007) argues that free reading cannot provide L2 readers with sufficient opportunities for acquiring vocabulary in order to reach an adequate level of reading comprehension of English texts. In this paper, we argue that (1) Cobb severely underestimates the amount of reading even a very modest reading habit would afford L2 readers, and therefore underestimates the impact of free reading on L2 vocabulary development; and (2) Cobb’s data show that free reading is in fact a very powerful tool in vocabulary acquisition

Is light reading enough to fully acquire academic language? The bridge hypothesis

The Bridge Hypothesis states that pleasure reading acts as a bridge between conversational and academic language, providing the competence that makes demanding texts more comprehensible. In two studies, D. Gardner argues that pleasure reading does not play a role in helping children understand academic texts, but a close look at the data shows that Gardner's evidence actually supports the Bridge Hypothesis.&nbsp

REMARKS ON LANGUAGE ACQUISITION AND LITERACY: LANGUAGE ACQUISITION AND TEACHING, FREE READING, "TEST-PREP" AND ITS CONSEQUENCES, THE USE OF THE FIRST LANGUAGE, WRITING, AND THE GREAT NATIVE SPEAKER TEACHER DEBATE

This paper reviews the arguments for comprehensible input (the"comprehension hypothesis" and discusses some of itsapplications to beginning and intermediate language teaching,including free voluntary reading as a bridge from conversationalto academic language. The comprehension hypothesis providessome guidance on the proper use of the first language in secondlanguage teaching and helps explain what writing can andcannot do. Finally, the comprehension hypothesis contributes tothe Great Native Speaker Teacher debate: We want teachers (1)to understand language acquisition, (2) to understand languagepedagogy, and (3) to speak the language well. My point is thatnumber (3) alone is not enough, even if the teacher is a nativespeaker.Keywords: comprehensible input, language acquisition,TPR, Natural Approach, TPRS, shelteredsubject matter teaching, free voluntary reading,writin

Open Problems on Central Simple Algebras

We provide a survey of past research and a list of open problems regarding central simple algebras and the Brauer group over a field, intended both for experts and for beginners.Comment: v2 has some small revisions to the text. Some items are re-numbered, compared to v

Modality-Independent Effects of Phonological Neighborhood Structure on Initial L2 Sign Language Learning

The goal of the present study was to characterize how neighborhood structure in sign language influences lexical sign acquisition in order to extend our understanding of how the lexicon influences lexical acquisition in both sign and spoken languages. A referent-matching lexical sign learning paradigm was administered to a group of 29 hearing sign language learners in order to create a sign lexicon. The lexicon was constructed based on exposures to signs that resided in either sparse or dense handshape and location neighborhoods. The results of the current study indicated that during the creation of the lexicon signs that resided in sparse neighborhoods were learned better than signs that resided in dense neighborhoods. This pattern of results is similar to what is seen in child first language acquisition of spoken language. Therefore, despite differences in child first language and adult second language acquisition, these results contribute to a growing body of literature that implicates the phonological features that structure of the lexicon is influential in initial stages of lexical acquisition for both spoken and sign languages. This is the first study that uses an innovated lexicon-construction methodology to explore interactions between phonology and the lexicon in L2 acquisition of sign language

Applications of patching to quadratic forms and central simple algebras

This paper provides applications of patching to quadratic forms and central simple algebras over function fields of curves over henselian valued fields. In particular, we use a patching approach to reprove and generalize a recent result of Parimala and Suresh on the u-invariant of p-adic function fields, for p odd. The strategy relies on a local-global principle for homogeneous spaces for rational algebraic groups, combined with local computations.Comment: 48 pages; connectivity now required in the definition of rational group; beginning of Section 4 reorganized; other minor change

From Bengali to English: sequential bilingualism of a second-generation British Bangladeshi

The paper discusses sequential language acquisition of the researcher's daughter Safa who transformed from a monolingual Bengali speaker to an almost monolingual English speaker in a few months after moving to the UK. Safa was born in Bangladesh and was a monolingual Bengali speaker until she was three years and nine months when the family moved to the UK. Unlike most research on sequential bilingualism, Safa's transition from Bengali to English went through a period of an invented language, which she developed and used for a few months. Safa then underwent language shift as Bengali became her passive language. Safa's loss of fluency in Bengali was mainly due to the absence of Bengali linguistic environment, because her family lived outside the community. Safa's mother's indifference to Bangladeshi ethnicity and her parents’ positive attitude towards Britishness meant that her decline in Bengali did not cause them much concern. Despite the lack of proficiency in Bengali, Safa still retains a strong ethnic Bangladeshi identity. Tabors and Snow’s four-stage developmental process of sequential second-language acquisition has been applied to find the similarities and differences in Safa's case, while language maintenance and shift theories have contributed to the analysis of the process of her language shift

Access to Print in Low‐Income and Middle‐Income Communities: An Ecological Study of Four Neighborhoods

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/88026/1/RRQ.36.1.1.pd