"Quit Talking and Learn English!": Conflicting Language Ideologies in an ESL Classroom

This article addresses the relationship between educational theory—as manifested in particular ideologies of teaching and learning—and classroom practice. Based on an ethnographic study of English-as-a-second-language (ESL) learning at a Canadian senior public school, I outline a conflict between two language ideologies that give shape to, and are shaped by, the classroom practices of the ESL teacher, his assistants, and the students. I discuss the implications of this ideological conflict in terms of the opportunities ESL students are given, and that they create for themselves, to practice speaking English. I end by outlining how these findings can be used to shape educational policy as it relates to ESL classroom curricula in order to create a more equitable learning environment for ESL students.     

A microbiological assay for sterigmatocystin,T-2 toxin and zearalenone

A survey was done to find microorganisms useful for assaying sterigmatocystin; T-2 toxin and zearalenone.Staphylococcus aureus was found to be sensitive to T-2 toxin and zearalenone;Bacillus cereus was found to be sensitive to T-2 toxin only; andEscherichia coli was sensitive to sterigmatocystin. The response of the organisms to sterigmatocystin; T-2 toxin and zearalenone was found to be linear between 4 and 100 μg with sterigmatocystin toE. coli; between 2 and 25 μg with T-2 toxin toStaph, aureus andB. cereus; and between 4 and 100 μg with zearalenone toStaph, aureus. The lower limits of sensitivity of the test were 2 μg T-2 toxin and zearalenone, and 4 μg sterigmatocystin. The assay is rapid (15–17 hrs); simple and inexpensive; and can be used to verify the toxicity of samples and to confirm thin layer chromatographic results.     

Neonatal development of ACTH-immunoreactive neurons in the rat

Using immunohistochemical techniques, the distribution of ACTH 25-39 immunoreactive perikarya and fibers was studied in the newborn rat. Perikarya and fibers were demonstrated on day 1 after birth in the diencephalon, mesencephalon, pons and medulla. However, the amount of material increased rapidly from the first to third day of postnatal development.     

Enzymatic activities of overexpressed herpes simplex virus DNA polymerase purified from recombinant baculovirus-infected insect cells.

Biochemical characterization of the herpes simplex virus (HSV) DNA polymerase, a model DNA polymerase and an important target for antiviral drugs, has been limited by a lack of pure enzyme in sufficient quantity. To overcome this limitation, the HSV DNA polymerase gene was introduced into the baculovirus, Autographa californica nuclear polyhedrosis virus, under the control of the polyhedrin promoter to give rise to a recombinant baculovirus, BP58. BP58-infected Spodoptera frugiperda insect cells expressed a polypeptide that was indistinguishable from authentic polymerase by several immunological and biochemical properties, at levels approximately ten-fold higher per infected cell than found in HSV-infected Vero cells. The DNA polymerase was purified to apparent homogeneity from BP58-infected insect cells. Using activated DNA as primer-template, the purified enzyme exhibited specific activity similar to that of enzyme isolated from HSV-infected Vero cells, indicating that additional polymerase-associated proteins from HSV-infected cells are not critical for activity with this primer-template. 3'-5' exonuclease activity co-purified with the BP58-expressed HSV DNA polymerase, demonstrating that this activity is intrinsic to the polymerase polypeptide. The purified enzyme also exhibited RNAse H activity. The recombinant baculovirus should permit detailed biochemical and biophysical studies of this enzyme.     

Influence of river inflows on plankton distribution around the southern perimeter of the Salton Sea,California

The influence of river inflows (2.5–5 g l⁻¹) on phytoplankton and zooplankton was assessed with samples collected at 17 sites around the 50 km perimeter of the southern basin of the Salton Sea (41–45 g l⁻¹) along the 5 m isobath on 2 September and 11 December 2000. Phytoplankton generally increased in abundance downcurrent of the points of inflow, but patterns in downcurrent abundance varied widely among species. Several diatom species showed large increases; Chaetoceros muelleri var subsalsum, Cylindrotheca closterium and Thalassionema sp. increased up to 800-fold in abundance by ca. 20 km downcurrent from inflow points in September. In contrast, the dinoflagellates Gyrodinium uncatenum and Prorocentrum minimum increased 6- and 4-fold, respectively, in December, and Gonyaulax grindleyi actually decreased downcurrent of the rivers in September. In September, patterns in downcurrent abundance were correlated with the ratio of cell surface area to cell biovolume, with species with high ratios showing the largest increases. Zooplankton abundances did not show regular trends downcurrent of river inflows except for the larvae of Balanus amphitrite, which increased in density ca. 100-fold. This increase most likely reflected the abundance of adult-colonized rocky substrates near river inflow points. The strong upcurrent trends documented for some species seemed to have been due to the injection of nutrient-rich water from central to nearshore areas and near-site mortality due to the presence of hydrogen sulfide. This study gives a first glimpse of the complexity of the responses of nearshore plankton to river inflow and provides evidence for how changes in factors such as current speed, nutrient supply and salinity stratification may influence plankton dynamics. Guest Editor: John M. Melack Saline Waters and their Biota     

Identification of novel small-molecule inhibitors of West Nile virus infection

West Nile virus (WNV) has spread throughout the United States and Canada and now annually causes a clinical spectrum of human disease ranging from a self-limiting acute febrile illness to acute flaccid paralysis and lethal encephalitis. No therapy or vaccine is currently approved for use in humans. Using high-throughput screening assays that included a luciferase expressing WNV subgenomic replicon and an NS1 capture enzyme-linked immunosorbent assay, we evaluated a chemical library of over 80,000 compounds for their capacity to inhibit WNV replication. We identified 10 compounds with strong inhibitory activity against genetically diverse WNV and Kunjin virus isolates. Many of the inhibitory compounds belonged to a chemical family of secondary sulfonamides and have not been described previously to inhibit WNV or other related or unrelated viruses. Several of these compounds inhibited WNV infection in the submicromolar range, had selectivity indices of greater than 10, and inhibited replication of other flaviviruses, including dengue and yellow fever viruses. One of the most promising compounds, AP30451, specifically blocked translation of a yellow fever virus replicon but not a Sindbis virus replicon or an internal ribosome entry site containing mRNA. Overall, these compounds comprise a novel class of promising inhibitors for therapy against WNV and other flavivirus infections in humans.