The effect of background knowledge on young children's comprehension of explicit and implicit information

Bibliography: leaves 15-16Supported in part by the National Institute of Educatio

Laminin-8/9 is synthesized by rat glomerular mesangial cells and is required for PDGF-induced mesangial cell migration

Laminin-8/9 is synthesized by rat glomerular mesangial cells and is required for PDGF-induced mesangial cell migration.BackgroundLaminin (LM), the major glycoprotein component of basement membranes is expressed as multiple isoforms in a developmentally regulated and tissue-specific manner. LM α4 has a limited tissue distribution and is highly expressed in the developing glomerulus. In the present study, we investigate the in vivo and in vitro expression and function of LM α4 in the glomerulus.MethodsLM α4 expression was examined by Northern blot, reverse transcription polymerase chain reaction (RT-PCR), Western blot, and immunofluorescence microscopy. Mesangial cells (MC) were plated on purified LM-1, LM-2, and LM-8/9. Immunofluorescence microscopy was performed to examine the cellular phenotypes induced by LM-1 and LM-8/9. A modified Boyden chamber method was used to assess laminin participation in platelet-derived growth factor (PDGF)-stimulated migration.ResultsmRNA for LMα4 is expressed in cultured rat MC, and isolated rat and mouse glomeruli, but not in cultured rat glomerular epithelial cells or glomerular endothelial cells. Using antibodies specific for LM α4, a 240 kD band was detected in MC extract and a slightly smaller band was identified in extracted rat glomeruli. Purified LM-8/9 had MC adhesive activity comparable to LM-1 and LM-2. MC attached to LM-8/9 exhibited a unique phenotype. In contrast to LM-1, attachment of MC to LM-8/9 produced a highly arborized cell morphology with significantly reduced formation of focal contacts or stress fibers. LM α4 is utilized by MC during PDGF-stimulated migration.ConclusionLM α4 is synthesized by MC and persists in the mature glomerulus. LM-8/9 stimulates a unique cellular morphology, and they are utilized in PDGF-induced migration. These factors suggest that LM α4 plays an important role in MC differentiation and in the maintenance of MC phenotype

El diálogo socrático como camino hacia la admiración y la Aletheia dentro de una investigación-acción cualitativa

In qualitative and action research, through Socratic dialogue, the researcher can help participants past a cognitive approach to the phenomenon, into a community of wonder (thaumazein), past observation of lived experience to foreboding and finally to openness. This openness serves as a ground for truth (aletheia). Researchers who try the Socratic approach may find it rewarding in the journey and in the research produced.En la investigación-acción de carácter cualitativo el investigador puede, por medio del diálogo socrático, ayudar a los participantes a transitar desde un acercamiento cognitivo a uno fenomenológico si se ubican en el seno de una comunidad de admiración (thaumazein), desde observación de las experiencias de vida a la intuición y al estado de apertura. Esta apertura es la base de la verdad (aletheia). Los investigadores que usen el enfoque socrático encontrarán recompensas tanto en su trabajo como en los resultados de sus indagaciones

New adult host records for three Buprestidae (Coleoptera) rarely encountered in the United States and significant extension of the known geographic range of \u3ci\u3eAgrilus pilosicollis\u3c/i\u3e Fisher

New adult host records of Agrilus langei Obenberger, A. pilosicollis Fisher, and Dicerca mutica LeConte (Coleoptera: Buprestidae) are reported. The known geographic range of A. pilosicollis is expanded from the type location in Kansas south to Texas and east to North Carolina. Images with key characters of each of the three species are included. Among the nearly 800 species of buprestids in North America (north of Mexico) are those known from very few specimens. Distribution and plant host information for such species is understandably limited and, in many cases, completely unknown (Nelson et al. 2008). A knowledge of host utilization is often the first step in under­standing the life history of such buprestid species. Adult host records of rarely encountered buprestids can be useful starting points to determine larval hosts, as adults of non-anthrophilous genera are frequently found feed­ing on larval plant hosts. Herein we report distribution and adult plant host records that may prove useful in future study of Agrilus langei Obenberger, A. pilosicollis Fisher and Dicerca mutica LeConte

Exotic pest insects: another perspective on coffee and conservation

Research on crop systems and biodiversity conservation in the tropics has mainly been concerned with how low to mid intensity agricultural systems can benefit from adjacent natural habitats by receiving ecosystem services from natural biodiversity. One intensively studied crop in this framework is coffee. Positive effects are relatively easy to quantify by comparing coffee yield and by recording native species diversity. However, a largely overlooked issue is how agricultural areas affect native organisms in adjacent natural habitats, for example through movement of pest species that could impose a risk of degrading these habitats. We give an example from Mauritius, where an introduced coffee pest severely reduces the reproductive success of a threatened endemic plant species. We argue that such effects may be more common than suggested by the literature, especially when crop and native plants are congeneric. In the long term, such negative effects may degrade natural habitats, thereby causing ecosystem services derived from these habitats to declin

Management of Potato Leafhopper, Empoasca fabae (Homoptera: Cicadellidae), on Alfalfa with the Aid of Systems Analysis

Efficient management of the potato leafhopper (Homoptera: Cicadellidae) on alfalfa requires a procedure for dealing with the complexities of the ecological and economic system. We developed a mathematical model to represent this agroecosystem and demonstrated how systems analysis can help to make management more efficient and less risky. Our management policies were based on two criteria: annual income calculated from the nutrient yields of three harvests, and level of carbohydrate reserve in the taproots at the end of the season, We determined the dynamic economic thresholds for controlling the leafhoppers as immigrants on each of the cuttings of alfalfa. During development of the thresholds we tested a variety of control tactics, including timing of harvests, We found that, for adult immigrants on the second crop, the economic thresholds increase exponentially as stem height increases, Tactics associated with these thresholds included insecticide treatments and early cutting of the second harvest. The results indicated that temperature pattern has an important effect on the economic thresholds and risk. Evaluation of the model and its results through sensitivity analysis, validation, and a comparison with current recommendations showed that the model can be a useful tool in research and managemen