Effects of Toyota Family Literacy Program on Reading Achievement of Kindergarten, First, Second, and Third Grade Students by Gender and Grade Level

For the last 15 years, federal legislation has required that public schools involve parents in their child‘s education. Yet, there has been no solid definition for parent involvement (also known as family literacy) and limited research on family literacy. This mixed study examined the influence of Toyota Family Literacy, which focuses on Hispanic immigrant families, on the literacy achievement of students in kindergarten through third grade, as well as parental efficacy in helping their child succeed in school, in three Northwest Arkansas Schools. The study examined student literacy achievement by gender and grade level using the Developmental Reading Assessment 2 (DRA2). The study also examined parental self-efficacy as measured with the Toyota Family Literacy Initial and Post Family Interview. In addition, the researcher examined predictive effects on parent perceived ability to help their child succeed in school. Data effects on student literacy achievement by gender were not significant; yet, data effects on student literacy achievement by grade level were different for kindergarten and third grade. Parental self-efficacy increase was significant, with no indicators contributing to the parental perceived ability. The researcher suggests future studies should include longitudinal studies to follow children and families over several years, as well as studies of other ethnicities

Mechanistic insights from a quantitative analysis of pollen tube guidance

<p>Abstract</p> <p>Background</p> <p>Plant biologists have long speculated about the mechanisms that guide pollen tubes to ovules. Although there is now evidence that ovules emit a diffusible attractant, little is known about how this attractant mediates interactions between the pollen tube and the ovules.</p> <p>Results</p> <p>We employ a semi-<it>in vitro </it>assay, in which ovules dissected from <it>Arabidopsis thaliana </it>are arranged around a cut style on artificial medium, to elucidate how ovules release the attractant and how pollen tubes respond to it. Analysis of microscopy images of the semi-<it>in vitro </it>system shows that pollen tubes are more attracted to ovules that are incubated on the medium for longer times before pollen tubes emerge from the cut style. The responses of tubes are consistent with their sensing a gradient of an attractant at 100-150 <it>μ</it>m, farther than previously reported. Our microscopy images also show that pollen tubes slow their growth near the micropyles of functional ovules with a spatial range that depends on ovule incubation time.</p> <p>Conclusions</p> <p>We propose a stochastic model that captures these dynamics. In the model, a pollen tube senses a difference in the fraction of receptors bound to an attractant and changes its direction of growth in response; the attractant is continuously released from ovules and spreads isotropically on the medium. The model suggests that the observed slowing greatly enhances the ability of pollen tubes to successfully target ovules. The relation of the results to guidance <it>in vivo </it>is discussed.</p

Drosophila katanin is a microtubule depolymerase that regulates cortical-microtubule plus-end interactions and cell migration

Regulation of microtubule dynamics at the cell cortex is important for cell motility, morphogenesis and division. Here we show that the Drosophila Katanin, Dm-Kat60, functions to generate a dynamic cortical-microtubule interface in interphase cells. In S2 cells, Dm-Kat60 concentrates at the interphase cell cortex where it suppresses the polymerization of microtubule plus-ends thereby preventing the formation of aberrantly dense cortical arrays. Dm-Kat60 also localizes to the leading edge migratory D17 cells and negatively regulates multiple parameters of their motility. Finally, in vitro, Dm-Kat60 severs and depolymerizes MTs from their ends. Based on these data, we propose that Dm-Kat60 removes tubulin from microtubule ends or lattice that contact specific cortical sites to preventing stable and/or lateral attachments. The asymmetric distribution of such an activity could help generate regional variations in MT behaviors involved in cell migration

The actin-binding ERM protein Moesin binds to and stabilizes microtubules at the cell cortex

Ezrin, Radixin, and Moesin (ERM) proteins play important roles in many cellular processes including cell division. Recent studies have highlighted the implications of their metastatic potential in cancers. ERM’s role in these processes is largely attributed to their ability to link actin filaments to the plasma membrane. In this paper, we show that the ERM protein Moesin directly binds to microtubules in vitro and stabilizes microtubules at the cell cortex in vivo. We identified two evolutionarily conserved residues in the FERM (4.1 protein and ERM) domains of ERMs that mediated the association with microtubules. This ERM–microtubule interaction was required for regulating spindle organization in metaphase and cell shape transformation after anaphase onset but was dispensable for bridging actin filaments to the metaphase cortex. These findings provide a molecular framework for understanding the complex functional interplay between the microtubule and actin cytoskeletons mediated by ERM proteins in mitosis and have broad implications in both physiological and pathological processes that require ERMs

An Osmotic Model of the Growing Pollen Tube

Pollen tube growth is central to the sexual reproduction of plants and is a longstanding model for cellular tip growth. For rapid tip growth, cell wall deposition and hardening must balance the rate of osmotic water uptake, and this involves the control of turgor pressure. Pressure contributes directly to both the driving force for water entry and tip expansion causing thinning of wall material. Understanding tip growth requires an analysis of the coordination of these processes and their regulation. Here we develop a quantitative physiological model which includes water entry by osmosis, the incorporation of cell wall material and the spreading of that material as a film at the tip. Parameters of the model have been determined from the literature and from measurements, by light, confocal and electron microscopy, together with results from experiments made on dye entry and plasmolysis in Lilium longiflorum. The model yields values of variables such as osmotic and turgor pressure, growth rates and wall thickness. The model and its predictive capacity were tested by comparing programmed simulations with experimental observations following perturbations of the growth medium. The model explains the role of turgor pressure and its observed constancy during oscillations; the stability of wall thickness under different conditions, without which the cell would burst; and some surprising properties such as the need for restricting osmotic permeability to a constant area near the tip, which was experimentally confirmed. To achieve both constancy of pressure and wall thickness under the range of conditions observed in steady-state growth the model reveals the need for a sensor that detects the driving potential for water entry and controls the deposition rate of wall material at the tip

Why organizational and community diversity matter:Representativeness and the Emergence of Incivility and Organizational Performance

Integrating sociological and psychological perspectives, this research considers the value of organizational ethnic diversity as a function of community diversity. Employee and patient surveys, census data, and performance indexes relevant to 142 hospitals in the United Kingdom suggest that intraorganizational ethnic diversity is associated with reduced civility toward patients. However, the degree to which organizational demography was representative of community demography was positively related to civility experienced by patients and ultimately enhanced organizational performance. These findings underscore the understudied effects of community context and imply that intergroup biases manifested in incivility toward out-group members hinder organizational performance

Markov and renewal models for total manpower system

This study compares the predictive utility of three stochastic models for both total manpower system and cohort personnel movement. The models are all discrete time versions, including a first order Markov chain, a Markov chain with duration of stay (semi-Markov) and a vacancy model having both renewal and Markov properties. The analysis covers a continuous 20 year period: 1950-1970 for a state police (U.S.A.) internal labor market. The simple Markov chain model is inadequate for long term cohort forecasts, but reasonably adequate for long term organizational forecasts. The semi-Markov model outperforms the simple Markov model for cohorts, but is surprisingly less accurate for the total organization. The heuristic information it portrays for the cohort is, however, quite informative. The best model for intermediate (5 year) and long term (10 year) forecasts in both cohort and organizational tests is the renewal type vacancy model. This finding is viewed as particularly important both in terms of empirical performance, which we expect can be improved due to the initial simplifying assumptions used, and in terms of further theoretical explication of the underlying causal process since internal staff flows are conceptualized as contingent on the opportunities available.