An evaluation of exercises for the development of word recognition and word meaning in grade five

Thesis (Ed.M.)--Boston Universit

Ecology of Juvenile Walleye Pollock, Theragra chalcogramma: Papers from the workshop "The Importance of Prerecruit Walleye Pollock to the Bering Sea and North Pacific Ecosystems" Seattle, Washington, 28-30 October 1993

The Alaska Fisheries Science Center (AFSC), National Marine Fisheries Service (NMFS), hosted an international workshop, 'The Importance of Prerecruit Walleye Pollock to the Bering Sea and North Pacific Ecosystems," from 28 to 30 October 1993. This workshop was held in conjunction with the annual International North Pacific Marine Science Organization (PICES) meeting held in Seattle. Nearly 100 representatives from government agencies, universities, and the fishing industry in Canada, Japan, the People's Republic of China, Russia, and the United States took part in the workshop to review and discuss current knowledge on juvenile pollock from the postlarval period to the time they recruit to the fisheries. In addition to its importance to humans as a major commercial species, pollock also serves as a major forage species for many marine fishes, birds, and mammals in the North Pacific region. (PDF file contains 236 pages.

An evaluation of exercises for the development of word recognition and word meaning in grade five

Thesis (Ed.M.)--Boston Universit

Do environmental conditions affect personality traits in Poison Dart Frog (Dendrobates auratus)?

Through the past few decades, there has been an increase on research centred on the proposition that animals can alter their behaviour phenotype to better cope with the environmental conditions through their lifetime. These changes can lead to individual differences in behaviour that are significantly relevant to conservation, in terms of anti-predator, exploratory and risk-taking behaviour. The captive environment is widely different from any wild habitat, if animals are being kept for conservation, it is imperative to consider how housing conditions can affect their behaviour and personality. The aim of this study was to understand the effect of environmental conditions on personality traits of Dendrobates auratus. A group of frogs was kept under basic standard conditions and a second group under environmental enriched conditions, different live plants, caves, hiding spots. During the length of the experiment, no alterations were made to the standard conditions group, while the enriched groups had changes made to their enclosure every 3 weeks. Feeding and water regime were the same for both groups. Standardised arena trials were used to test exploratory and risk-taking behaviour on both experimental groups. We observed that frogs kept on basic conditions scored higher for both exploratory and risk-taking behaviour, suggesting that these differences could be adaptive responses to their environment conditions. Frogs with environment enrichment had more hiding spots and more optimal conditions with no necessity to explore to find a more suitable habitat. Frogs under basic conditions had less hiding opportunities and a suboptimal habitat, therefore a need to explore for a more suitable environment. During a reintroduction programme, ideally animals should stay on the release habitat, with many studies showing that bolder and exploratory animals having a higher mortality during reintroductions. This study highlight the effect of housing conditions for zoo kept animals on behavioural traits, especially if these are considered for future reintroductions

A 3D <i>in vitro</i> model reveals differences in the astrocyte response elicited by potential stem cell therapies for CNS injury.

Aim: This study aimed to develop a 3D culture model to test the extent to which transplanted stem cells modulate astrocyte reactivity, where exacerbated glial cell activation could be detrimental to CNS repair success. Materials & methods: The reactivity of rat astrocytes to bone marrow mesenchymal stem cells, neural crest stem cells (NCSCs) and differentiated adipose-derived stem cells was assessed after 5 days. Schwann cells were used as a positive control. Results: NCSCs and differentiated Schwann cell-like adipose-derived stem cells did not increase astrocyte reactivity. Highly reactive responses to bone marrow mesenchymal stem cells and Schwann cells were equivalent. Conclusion: This approach can screen therapeutic cells prior to in vivo testing, allowing cells likely to trigger a substantial astrocyte response to be identified at an early stage. NCSCs and differentiated Schwann cell-like adipose-derived stem cells may be useful in treating CNS damage without increasing astrogliosis

A multi-well plate model of reactive gliosis for high throughput screening of potential CNS therapies

Reactive astrogliosis is an important feature of CNS damage and disease which involves changes in astrocyte phenotype and morphology. In particular, CNS trauma can lead to the formation of a glial scar, a three dimensional (3D) mesh of astrocyte processes that can form a physical and chemical barrier to neuronal regeneration, which is a potential target for CNS drug and cell therapy. However, reactive gliosis is difficult to isolate and monitor in typical animal models of CNS damage. In monolayer culture systems astrocytes adopt a highly reactive phenotype, limiting the range of available models suitable for research in this area. Our previous 3D cell culture systems allow astrocytes to be maintained with a relatively unreactive phenotype until stimulated, whereupon a classical reactive astrocyte response can be monitored. The aim of the current work is to adapt this approach in order to develop a multi-well plate system to provide a reliable, consistent model of reactive gliosis for high throughput screening and research. Once baseline viability and phenotype of primary rat astrocytes were investigated in these models, reactivity was triggered using treatments such as TGFβ1, as seen in Figure 1, hypoxia and low glucose. Outputs included confocal microscopy and 3D image analysis, Western blotting and RT-PCR to quantify markers such as GFAP and CSPG in test and control gels. Using GFP-labelled astrocytes permitted monitoring of cytoplasmic volume and shape, giving an additional measure of astrocyte hypertrophic response within stimulated conditions. The robust protocol that we have developed can form a basis to investigate astrocyte biology in a highly controlled environment, and to model phenotypic features of astrocytes in both damaged and undamaged CNS. A reproducible multi-well plate system will provide an experimental platform which allows potential CNS therapies to be screened at high-throughput, and the effects of potential modulators of astrocyte reactivity to be investigated simply and systematically

Microscopic biophysical model of self-organization in tissue due to feedback between cell- and macroscopic-scale forces

We develop a microscopic biophysical model for self-organization and reshaping of artificial tissue, that is codriven by microscopic active forces between cells and an extracellular matrix (ECM), and macroscopic forces that develop within the tissue, finding close agreement with experiment. Microscopic active forces are stimulated by μm-scale interactions between cells and the ECM within which they exist, and when large numbers of cells act together these forces drive, and are affected by, macroscopic-scale self-organization and reshaping of tissues in a feedback loop. To understand this loop, there is a need to (1) construct microscopic biophysical models that can simulate these processes for the very large number of cells found in tissues, (2) validate and calibrate those models against experimental data, and (3) understand the active feedback between cells and the extracellular matrix, and its relationship to macroscopic self-organization and reshaping of tissue. Our microscopic biophysical model consists of a contractile network representing the ECM, that interacts with a large number of cells via dipole forces, to describe macroscopic self-organization and reshaping of tissue. We solve the model using simulated annealing, finding close agreement with experiments on artificial neural tissue. We discuss the calibration of model parameters. We conclude that feedback between microscopic cell-ECM dipole interactions and tissue-scale forces is a key factor in driving macroscopic self-organization and reshaping of tissue. We discuss the application of the biophysical model to the simulation and rational design of artificial tissues