The relationship between Algebra Nation usage and high‐stakes test performance for struggling students

Although the use of technology in the K12 classroom has been shown to have a positive impact, research on the use of open education resources (OER) is relatively limited, especially research focusing on low‐achieving students. The present study examines the relationship between usage of Algebra Nation, a self‐guided system that provided instructional videos and practice problems, and the performance of students who had failed the state‐administered Algebra I end‐of‐course (EOC) assessment the previous year. Indicators of usage of Algebra Nation consisted of logins, video views, and practice questions answered. Path analyses and logistic regressions were used to evaluate relationships between usage indicators and algebra scores, controlling for number of absences, free/reduced lunch eligibility, Hispanic/Latino origin, race, and gender. The results indicate that higher levels of logins, video views, and practice questions answered were related to higher scores when the students re‐took the assessment. Logins and practice questions were also related to increases in odds of passing the Algebra I EOC assessment, but not video views. The results suggest that there may be benefits to technology use in the form of an OER adopted by students and teachers on an informal basis and link self‐regulated learning strategies to student achievement.     

Temporal Data Mining for Educational Applications

Intelligent tutoring systems (ITSs) acquire rich data about students' behavior during learning; data mining techniques can help to describe, interpret and predict student behavior, and to evaluate progress in relation to learning outcomes. This paper surveys a variety of data mining techniques for analyzing how students interact with ITSs, including methods for handling hidden state variables, and for testing hypotheses. To illustrate these methods we draw on data from two ITSs for math instruction. Educational datasets provide new challenges to the data mining community, including inducing action patterns, designing distance metrics, and inferring unobservable states associated with learning.     

Silica nanoparticles inhibit the cation channel TRPV4 in airway epithelial cells

Background

Silica nanoparticles (SiNPs) have numerous beneficial properties and are extensively used in cosmetics and food industries as anti-caking, densifying and hydrophobic agents. However, the increasing exposure levels experienced by the general population and the ability of SiNPs to penetrate cells and tissues have raised concerns about possible toxic effects of this material. Although SiNPs are known to affect the function of the airway epithelium, the molecular targets of these particles remain largely unknown. Given that SiNPs interact with the plasma membrane of epithelial cells we hypothesized that they may affect the function of Transient Receptor Potential Vanilloid 4 (TRPV4), a cation-permeable channel that regulates epithelial barrier function. The main aims of this study were to evaluate the effects of SiNPs on the activation of TRPV4 and to determine whether these alter the positive modulatory action of this channel on the ciliary beat frequency in airway epithelial cells.

Results

Using fluorometric measurements of intracellular Ca²⁺ concentration ([Ca²⁺]_i) we found that SiNPs inhibit activation of TRPV4 by the synthetic agonist GSK1016790A in cultured human airway epithelial cells 16HBE and in primary cultured mouse tracheobronchial epithelial cells. Inhibition of TRPV4 by SiNPs was confirmed in intracellular Ca²⁺ imaging and whole-cell patch-clamp experiments performed in HEK293T cells over-expressing this channel. In addition to these effects, SiNPs were found to induce a significant increase in basal [Ca²⁺]_i, but in a TRPV4-independent manner. SiNPs enhanced the activation of the capsaicin receptor TRPV1, demonstrating that these particles have a specific inhibitory action on TRPV4 activation. Finally, we found that SiNPs abrogate the increase in ciliary beat frequency induced by TRPV4 activation in mouse airway epithelial cells.

Conclusions

Our results show that SiNPs inhibit TRPV4 activation, and that this effect may impair the positive modulatory action of the stimulation of this channel on the ciliary function in airway epithelial cells. These findings unveil the cation channel TRPV4 as a primary molecular target of SiNPs.

     

Fatigue life assessment of nodular cast iron containing casting defects

The fatigue behaviour of a nodular cast iron containing casting defects has been investigated in the high-cycle fatigue regime. In this paper, we propose a fatigue life assessment model for flawed materials based on a fracture mechanics approach which takes into account the position and size of the defect, short crack behaviour and the notch effect introduced by the defect. The fatigue behaviour of smooth samples, and long and short crack behaviour have been experimentally determined in order to identify the relevant mechanical parameters; these being introduced into the model. An experimental study has been made both in air and in vacuum in order to account for the position of the defect, noting that internal defects are supposed to be under vacuum conditions. Experimental results, which are based on a two-crack front-marking technique specially developed for this study, show that the propagation of natural cracks is controlled by the effective stress intensity factor in air as well as in vacuum. The K calculation for a short crack in the stress field of a notch is analysed using numerical elastic–plastic results. Comparison between experimental results and the computation of fatigue life for fatigue lives less than 10⁶ cycles shows that the fatigue behaviour of nodular cast iron is controlled by a propagation process. The model proposed is thus relevant for fatigue lives less than 10⁶ cycles so that the defect can be considered as a crack and the initiation stage neglected. Closer to the fatigue limit, this study shows that the initiation stage should be considered in the assessment of fatigue life of nodular cast iron, because a single macroscopic propagation assessment is not enough to describe the whole fatigue life. The defect cannot be considered as a pre-existent crack in the high-cycle fatigue range (>10⁶ cycles), and the initiation stage that contains microcrack propagation around the defect should be evaluated when assessing the high-cycle fatigue life of nodular cast iron.     

Helping families move: Relocation counseling for housing-voucher recipients

As the U.S. Department of Housing and Urban Development (HUD) shifts its emphasis from project-based subsidies to housing vouchers, a key question is the amount of relocation help that should be provided to voucher recipients. To address these and related issues, this article examines the use of and influence of relocation counseling at four distressed federally subsidized housing developments (in Baltimore, Maryland; Newport News, Virginia; Kansas City, Missouri; and San Francisco, California) where families were provided with vouchers and relocation counseling in order to expedite moves into the private housing market. Both qualitative and quantitative analysis techniques were used to examine the different approaches to relocation counseling provided by four types of providers: 1) community-based non-profit housing agencies; 2) a private company and its subcontractor, an out-of-town consultant specializing in relocation counseling; 3) a state housing agency; and 4) the on-site housing management company. Underutilization of relocation counseling was a problem: only two-fifths of the sample reported using relocation services. Middle-aged tenants and those at the Baltimore site were most likely to take advantage of the services; those living in overcrowded units were least likely. Programs need to be developed to increase participation rates while recognizing that tenant involvement must remain voluntary in nature at such sites. Although there was some evidence that the more intensive relocation counseling provided in Newport News opened up more housing options for residents, in general the counseling had limited impact. Those who used relocation counseling did not consider more housing options than others, nor were they more likely to focus their housing search on distant neighborhoods. Furthermore, residents depended on friends and relatives, rather than relocation counselors, to learn about their new home. Even though many respondents made short-distance moves (especially in Baltimore and Kansas City), they usually were able to improve their housing and neighborhood conditions. These findings suggest that it may be unreasonable to expect families-particularly those relying on public transportation—to relocate to new and unfamiliar neighborhoods without support, or without intensive counseling, encouraging them to do so. Spatial deconcentration may not always be an appropriate goal for all voucher recipients. David P. Varady co-principal investigator, Professor of Planning is Professor of Planning at the University of Cincinnati. Professor Varady has written widely about community conservation and housing policy, both in the United States and the United Kingdom. His most recent book, co-edited with Wolfgang F.E. Preiser and Francis P. Russell,New Directions in Urban Public Housing, was published by the Center for Urban Policy Research, Fall, 1988. Carole C. Walker co-principal investigator, is Assistant Director of the Center for Urban Policy Research at Rutgers University. In her years at the Center, she has studied a broad range of public policy issues, including program evaluation, affordable housing,subdivision regulations, and land use development. She is the author of numerous research studies and co-author with David Listokin ofThe Subdivision and Site Plan Handbook. Kirk McClure investigator, is an Associate Professor with the Graduate Program in Urban Planning at the University of Kansas. His teaching and research interests are in the areas of housing and community development. He has recently completed research evaluating the ten-year performance of the Low-Income Housing Tax Credit program and is now engaged in an examination of the secondary mortgage market as an aid to affordable housing. Janet Smith-Heimer, investigator, is the founding principal of Bay Area Economics (BAE), a national consulting firm specializing in urban and real estate economics. She has been actively engaged in urban development since 1978 and has developed expertise in affordable housing, economic development, and military base closure. Sherry Larkins research assistant, is a Ph.D. candidate in sociology at Rutgers University. Her areas of interest are race relations, urban sociology, and substance abuse.     

Cancer stem cell sorting from colorectal cancer cell lines by sedimentation field flow fractionation

Recently, cancer stem cells (CSCs) have been identified in many types of cancers, such as colorectal cancer (CRC). CSCs seem to be involved in initiation, growth, and tumor metastasis, as well as in radio- and chemotherapy failures. CSCs appears as new biological targets for cancer therapy, requiring the development of noninvasive cell sorting methods. In this study, we used sedimentation field flow fractionation (SdFFF) to prepare enriched populations of CSCs from eight cell lines corresponding to different CRC grades. On the basis of phenotypic and functional characterizations, "hyperlayer" elution resulted in a fraction overexpressing CSC markers (CD44, CD166, EpCAM) for all cell lines. CSCs were eluted in the last fraction for seven out of eight cell lines, but in the first for HCT116. These results suggest, according to the literature, that two different pools of CSCs exist, quiescent and activated, which can both be sorted by SdFFF. Moreover, according to CSC properties, enriched fractions are able to form colonies.     

Assessment of biogas potential hazards

Biogas produced from anaerobic fermentation of organic substances represents an alternative renewable energy source. Its utilization would contribute to substantial reduction of the solid waste volume in land-filling and incineration. Biogas so produced could be utilized on site or it could be injected into the natural gas distribution network. Microbiological and chemical compositions of different biogas types were determined in order to conduct qualitative and quantitative risk assessments of the potential health hazards associated with biogas use for cooking. Biogas types that could be allowed for injection in the natural gas pipelines were listed with recommendations, while outlining the European biogas injection policy. Results indicated that the injection of the processed biogas in the distribution network did not present any additional chemical or microbiological risk to consumers when compared to natural gas, provided that the biogas resulted from the fermentation of non-dangerous waste. However, since this study did not examine the microbiological and chemical composition of biogas originating from wastewater sludges and/or industrial wastes, the injection of this type of biogas into the gas distribution network should not be allowed unless a similar risk evaluation study is conducted for each case.     

Synthesis by Spark Plasma Sintering: A new way to obtain electrode materials for lithium ion batteries

In the search of high-performance materials for lithium ion batteries, Li₂CoPO₄F offers many advantages like high theoretical capacity and high operating potential. The synthesis of Li₂CoPO₄F has been reinvestigated considering a conventional solid state reaction and an unconventional way. Due to the long heat-treatments required by the conventional approach, a beginning of grains coalescence is observed. Limiting particles growth has been allowed by a shorter reaction done by SPS (Spark Plasma Sintering). By this method, the synthesis of Li₂CoPO₄F was greatly shortened (from 10 h to 9 min), which favours the getting of submicrometric particles. The comparison of the electrochemical properties of the Li₂CoPO₄F obtained by the different ways confirms the advantages of SPS synthesis in performance enhancement.