Cognitive benefits and costs of bilingualism in elementary school students: The case of mathematical word problems.

Previous research has emphasized the importance of language for learning mathematics. This is especially true when mathematical problems have to be extracted from a meaningful context, as in arithmetic word problems. Bilingual learners with a low command of the instructional language thus may face challenges when dealing with mathematical concepts. At the same time, speaking two languages can be associated with cognitive benefits with regard to attentional control processes, although such benefits have only been found in highly proficient bilinguals. In the present study, we attempted to disentangle the effects of bilingual proficiency on mathematical problem solving in Turkish–German bilingual elementary school students. We examined whether the positive cognitive effects of bilingualism could be found not only in highly proficient bilinguals but also in students with an immigrant background and a low command of the instructional or native language. Our findings emphasize the importance of language proficiency for mathematics problem solving, as shown by the predictive value of students' proficiency in the language of testing (German/Turkish) for their performance on mathematical word problems. No additional effect of the language of instruction (German) was found for problem solving in the bilingual students' native language (Turkish). Furthermore, bilinguals gained scores comparable to those of their monolingual peers on word problems that required attentional control skills although performing significantly below their monolingual classmates on ordinary word problems, suggesting that bilinguals have an advantage when it comes to attentional control. Finally, bilingual students with a relatively high command of the instructional language performed better on word problems presented in German than on those presented in Turkish, thus facing cognitive costs when transferring knowledge from one language to the other. Implications of our findings for bilingual education are discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

The role of proteolysis in the processing and assembly of 11S seed globulins

11S seed storage proteins are synthesized as precursors that are cleaved post-translationally in storage vacuoles by an asparaginyl endopeptidase. To study the specificity of the reaction catalyzed by this asparaginyl endopeptidase, we prepared a series of octapeptides and mutant legumin B and G4 glycinin subunits. These contained amino acid mutations in the region surrounding the cleavage site. The endopeptidase had an absolute specificity for Asn on the N-terminal side of the severed peptide bond but exhibited little specificity for amino acids on the C-terminal side. The ability of unmodified and modified subunits to assemble into hexamers after post-translational modification was evaluated. Cleavage of subunits in trimers is required for hexamer assembly in vitro. Products from a mutant gene encoding a noncleavable prolegumin subunit (LeBDeltaN281) accumulated as trimers in seed of transgenic tobacco, but products from the unmodified prolegumin B gene accumulated as hexamers. Therefore, the asparaginyl endopeptidase is required for hexamer assembly.     

The fibroblast-specific MAb AS02: a novel tool for detection and elimination of human fibroblasts

PURPOSE: The earliest stages of Hodgkin's disease are associated with excellent short-term survival with radiation therapy. This has led to controversies regarding pretreatment evaluation, the extent of irradiation, the role of chemotherapy, and the relative importance of prognostic factors. Long-term results were sought to address these controversies. METHODS AND MATERIALS: A retrospective study was conducted of patients with Stage I Hodgkin's disease treated at the M. D. Anderson Cancer Center from 1967 through 1987. The median age at presentation of 145 patients was 31 years, and the male-to-female ratio was 1.8. Pretreatment evaluation included lymphangiography and bone marrow aspiration and biopsy in all patients. Laparotomy was performed in 101 of the 145 patients (70%). There were 133 patients with supradiaphragmatic presentations; 12 patients had infradiaphragmatic adenopathy. Only five patients had B symptoms (3.5%). Histologic subtypes of the disease included lymphocyte predominance 17.9%, nodular sclerosis 40.7%, mixed cellularity 40.7%, and one unclassified Hodgkin's disease with primary splenic involvement. All patients were treated with radiotherapy, and 16 (11%) also received combination chemotherapy as part of their initial treatment. Radiotherapy techniques included involved/regional field in 49%, extended field in 42.7% (mantle or inverted Y), and subtotal nodal irradiation in 8.3%. Follow-up extended from a minimum of 30-339 months, with a median period of observation of 16.5 years. RESULTS: The median survival was 13.7 years. The 10- and 20-year survival rates were 83% and 66%, respectively. The only factor important for decreased survival was age >40 years at diagnosis (p < 0.0001). Out of 43 deaths, 11 were the result of Hodgkin's disease and the remaining 32 resulted from intercurrent disease, including treatment-related causes. Median freedom from progression was 10.5 years, and the 10- and 20-year freedom from progression were 76% and 69%, respectively. Out of 39 relapses, 5 (13%) occurred beyond 10 years. Women had higher freedom from progression (p = 0.0534) than men. Age, histology, bulk of disease, site of involvement including the mediastinal presentations, and the addition of chemotherapy did not influence the freedom of progression. Although very few patients (12 of 145) received subtotal nodal irradiation, the freedom from progression at 10 years was 91.7% for this group versus 64.7% for the group of patients who were treated with more limited techniques. CONCLUSION: Treatment with radiation therapy for patients with Stage I Hodgkin's disease leads to an excellent outcome, but patients require long-term surveillance as late relapses are not rare. Age is the only factor that affects survival, and gender marginally affects freedom from progression. Subtotal nodal irradiation may improve freedom from progression; further investigation of this treatment is justified.     

Flow structures in MBR-tanks.

In this paper a CFD model is presented that allows for an approximation of the flow field within MBR-tanks. The technique is demonstrated by means of two examples considering both hollow-fibre and sheet-membrane modules. The flow field is computed and a comparison between measured and computed flow velocities shows the good quality of the numerical model.     

Over-expression of plant 14-3-3 proteins in tobacco: enhancement of the plasmalemma K+ conductance of mesophyll cells

Two cDNA clones encoding 14-3-3 homologous proteins were isolated from Vicia faba. Deduced amino acid sequences share different degrees of homology with other plant 14-3-3 proteins. Both clones, under the control of the CaMV 35S promoter, were transformed into tobacco plants. Immunoblotting showed three different forms of ca. 31, 34, and 37 kDa, indicating a covalent modification of the expressed 14-3-3 proteins. These forms were mainly present in the microsomal fraction. Patch-clamp studies of mesophyll protoplasts of the transformants revealed a strongly enhanced K+ conductance compared to the wild type. This indicates the involvement of 14-3-3 proteins in ion channel regulation, presumably by modulating kinase activities or binding the channel.     

Biochemical Basis of Xylooligosaccharide Utilisation by Gut Bacteria

Xylan is one of the major structural components of the plant cell wall. Xylan present in the human diet reaches the large intestine undigested and becomes a substrate to species of the gut microbiota. Here, we characterised the capacity of Limosilactobacillus reuteri and Blautia producta strains to utilise xylan derivatives. We showed that L. reuteri ATCC 53608 and B. producta ATCC 27340 produced β-D-xylosidases, enabling growth on xylooligosaccharide (XOS). The recombinant enzymes were highly active on artificial (p-nitrophenyl β-D-xylopyranoside) and natural (xylobiose, xylotriose, and xylotetraose) substrates, and showed transxylosylation activity and tolerance to xylose inhibition. The enzymes belong to glycoside hydrolase family 120 with Asp as nucleophile and Glu as proton donor, as shown by homology modelling and confirmed by site-directed mutagenesis. In silico analysis revealed that these enzymes were part of a gene cluster in L. reuteri but not in Blautia strains, and quantitative proteomics identified other enzymes and transporters involved in B. producta XOS utilisation. Based on these findings, we proposed a model for an XOS metabolism pathway in L. reuteri and B. producta strains. Together with phylogenetic analyses, the data also revealed the extended xylanolytic potential of the gut microbiota.     

Scope of linguistic influence: Does a classifier system alter object concepts?

Whether and to what extent conceptual structure is universal is of great importance for understanding the nature of human concepts. Two major factors that might affect concepts are language and culture. The authors investigated whether these 2 factors affect concepts of everyday objects in any significant ways. Specifically, they tested (a) whether the system of grammatical categorization by classifiers influenced the conceptual structure of speakers of classifier languages, and (b) whether Westerners organized object concepts around taxonomic relations whereas Easterners organized them around thematic relations, as proposed by R. E. Nisbett (2003). The relative importance of 3 types of relations--taxonomic, thematic, and classifier--for Chinese and German speakers was tested using a range of tasks, including categorization, similarity judgment, property induction, and fast-speed word-picture matching. Some support for linguistic relativity as well as for the cultural-specific cognition proposal was found in some tasks, but these effects were miniscule compared with the importance of taxonomic and thematic relations for both language-culture groups. The authors conclude that the global structure of everyday object concepts is strikingly similar across different cultures and languages. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Genetic engineering for high methionine grain legumes

Methionine (Met) is the primary limiting essential amino acid in grain legumes. The imbalance in amino acid composition restricts their biological value (BV) to 55 to 75% of that of animal protein. So far improvement of the BV could not be achieved by conventional breeding. Therefore, genetic engineering was employed by several laboratories to resolve the problem. Three strategies have been followed. A) Engineering for increased free Met levels; B) engineering of endogenous storage proteins with increased numbers of Met residues; C) transfer of foreign genes encoding Met-rich proteins, e.g. the Brazil nut 2S albumin (BNA) and its homologue from sunflower, into grain legumes. The latter strategy turned out to be most promising. In all cases the gene was put under the control of a developmentally regulated seed specific promoter and transferred into grain legumes using the bacterial Agrobacterium tumefaciens-system. Integration into and copy numbers in the plant genome as well as Mendelian inheritance and gene dosage effects were verified. After correct precursor processing the mature 2S albumin was intracellularly deposited in protein bodies which are part of the vacuolar compartment. The foreign protein amounted to 5 to 10% of the total seed protein in the best transgenic lines of narbon bean (Vicia narbonensis L., used in the authors' laboratories), lupins (Lupinus angustifolius L., used in CSIRO, Australia), and soybean (Glycine max (L.) Merr., used by Pioneer Hi-Bred, Inc., USA). In the narbon bean the increase of Met was directly related to the amount of 2S albumin in the transgenic seeds, but in soybean it remained below the theoretically expected value. Nevertheless, trangenic soybean reached 100%, whereas narbon bean and lupins reached approximately 80% of the FAO-standard for nutritionally balanced food proteins. These results document that the Met problem of grain legumes can be resolved by genetic engineering.