Evaluation of the effect of a digital mathematics game on academic achievement

Digital games are widely popular and interest has increased for their use in education. Digital games are thought to be powerful instructional tools because they promote active learning and feedback, provide meaningful contexts to situate knowledge, create engagement and intrinsic motivation, and have the ability individualize instruction. However, claims about the potential benefits of digital games in education have outpaced quality empirical research on their effectiveness in K-12 settings. The purpose of this study was to investigate the effectiveness of a mathematics digital game, Ko’s Journey, on seventh grade students’ mathematics achievement as defined by a researcher-constructed test aligned with the Common Core Mathematics Standards (National Governors Association Center for Best Practices, Council of Chief State School Officers, 2010) and measured on a Rasch (1960) unidimensional equal-interval scale. This research was conducted using secondary data from a pretest-posttest control group design study with a total of 371 seventh grade students from 10 classrooms. Classroom teachers randomly assigned their classroom sections to play the mathematics digital game or served as a wait-listed control group and continued using the typical mathematics curriculum. Hierarchical linear modeling (HLM) and Rasch differential item functioning were used to determine the effect of the intervention on student’s mathematics achievement. Hierarchical linear modeling analyses, using person ability logit estimates derived from the Rasch scaling, concluded that the Ko’s Journey intervention did not have a significant effect on posttest scores. The HLM analyses revealed a significant positive relationship between the students’ individual pretest and posttest scores and the classroom average pretest and posttest scores. Using the Rasch differential item functioning, six assessment items were significantly less difficult for the experimental group compared to the control group; this suggested that the intervention was successful in teaching the mathematics targeted by the items. Technological problems experienced in the classrooms and differential implementation of the game among teachers confounded an accurate estimate of the efficacy of the digital game to improve academic achievement

The impact of smallholder irrigation on household welfare: The case of Tugela Ferry irrigation scheme in KwaZulu-Natal, South Africa

The potential of smallholder irrigated agriculture to enhance food security and alleviate rural poverty has led the South African Government to prioritise and invest significantly in irrigation establishment, rehabilitation and revitalisation. The question addressed in this study pertains to the extent to which smallholder irrigation has been able to reduce poverty in the rural communities to justify this investment. Using a sample of 251 farmers, this study found that factors such as land size, perceived soil fertility, household size, and access to support services were significant predictors of irrigation participation. The results from the treatment effect model indicated that access to irrigation plays a positive role in the welfare of rural households, with irrigators spending about ZAR2 000 per adult equivalent on consumption more than the non-irrigators. The study, therefore, concluded that government investments in smallholder irrigation for poverty reduction are justified. The other factors that influenced household consumption were off-farm income, land size, livestock size, education level, family size and access to support services and infrastructure. The study recommends that investments in smallholder irrigation continue for poverty reduction, and that priority should also be on finding other feasible rural micro-projects and development initiatives to complement smallholder irrigation and significantly reduce rural poverty.Keywords: smallholder irrigation, poverty, food security, treatment effect model, Foster Greer Thorbecke (FGT) poverty measure

Collective action and participation in irrigation water management: A case study of Mooi River Irrigation Scheme in KwaZulu-Natal Province, South Africa

In line with the current focus of most developing countries to transfer management of communal irrigation schemes from state to users, an understanding of the determinants of farmer participation in collective activities forms the basis to improve the management of previously government-funded schemes, which are characterised by poor maintenance and performance when farmers are left to manage the schemes on their own. Cross-sectional data collected from 307 respondents in the Mooi River Irrigation Scheme (MRIS) in KwaZulu-Natal were used to identify the determinants of farmer participation in collective activities. The results of the Tobit and Ordered Probit models suggest that collective activities are negatively affected by low farmer-literacy levels. Number of consecutive days that farmers spend without access to irrigation water per week was used as a proxy for water scarcity, and was confirmed to be a significant determinant of farmer participation. The existing incentives for water-users in the MRIS need to be improved to encourage farmer participation in collective water management. This calls for strengthening of local water management systems and institutional policies to ensure maximum benefits from participating in collective activities. The study noted the complexity of managing common pool resources at a localised level, and pointed to the need to further understand the institutional dynamics in which smallholder irrigation farmers operate.Keywords: Collective action, participation intensity, smallholder irrigation scheme, South Afric

Brief communication: Low prevalence of HIV infection, and knowledge, attitude and practice on HIV/AIDS among high school students in Gondar, Northwest Ethiopia

HIV/AIDS is a major public health problem in Ethiopia. Therefore, a school based cross-sectional study was conducted in Gondar; Northwest Ethiopia to determine the seroprevalence of HIV infection and to assess Knowledge, attitude and practice related to HIV/AIDS. A total of 565 students were included in the study. The seroprevalence of HIV infection was 1.1%. Sexual contact with commercial sex worker or non-regular partner was reported by 16.7% of the students. Only 58.5% of those who practice sex used condoms. History of sexually transmitted diseases was reported by 10.7% of the sexually active students. The majority (96.6%) reported unprotected sex, unsafe blood transfusion, contaminated needles and mother to child transmissions as common ways of HIV transmission. Abstinence, faithfulness to one\'s partner and use of condom as means to prevent transmission of HIV was responded by 84.1%, 60.4% and 41.8% of the students, respectively. Over 82% demanded screening for HIV as a precondition for marriage and 97.2% agreed to have a VCT service. The findings of the study indicate that the prevalence of HIV infection is low among high school students in Gondar. The students had adequate knowledge about HIV/AIDS and VCT despite the risky practices. Continued health education is needed to bring behavioral changes.The Ethiopian Journal of Health Development Vol. 21 (2) 2007: pp. 179-18

AWG-DBR-based WDM transmitter fabricated in an InP generic foundry platform

We report a novel narrow-linewidth WDM transmitter operating at 10 Gbps per transmission channel with 275 kHz optical linewidth. The device, which integrates an AWG-based laser using selective DBR-mirrors with a Mach-Zehnder modulator array, has been fabricated in a multi-project wafer run in a generic InP-based foundry process.</p

Indium phosphide photonic circuits on silicon electronics

The intimate integration of photonics and electronics in transceivers facilitates energy-efficiency, bandwidth acceleration and a route to radical miniaturization. We present and implement a wafer-to-wafer integration method which combines electronic and photonic foundry technologies

Athermal colorless C-band optical transmitter system for passive optical networks

This paper reports an uncooled transmitter system using a digital super-mode (DS) distributed Bragg reflector (DBR) tunable laser, which is able to act as an athermal, wavelength agnostic transmitter suitable for wavelength division multiplexed (WDM) passive optical network (PON) applications. An open-loop laser current control algorithm is designed to compensate autonomously for wavelength drift, thus allowing constant operating wavelength to be achieved regardless of ambient temperature. An improved wavelength accuracy of ±3 GHz is achieved when using low bandwidth feedback from the central office using information from a centralized shared wavelength locker. The entire laser start-up, channel selection and subsequent wavelength control is autonomous and has been implemented on micro-controllers and field programmable gate arrays. We demonstrate a three channel WDM-PON system comprising an uncooled packaged DS-DBR laser in the presence of two neighboring interfering channels. Error free transmission over 40 km single mode fiber of 10 Gb/s externally modulated NRZ data, is achieved for each of 48 C-band channels on the 100 GHz ITU grid. Successful athermal operation is demonstrated by sweeping the ambient temperature of the laser from 15 to 70 °C with a maximum wavelength deviation for any channel of no more than 0.1 nm.This work has been supported by the Technology Strategy Board, UK and by the German ministry for education and research, through the EU ERA-NET+ projects PIANO+ IMPACT (BMBF grant: 13N11434) and TUCAN (BMBF grant: 13N11573). We also acknowledge the support of the UK Engineering and Physical Sciences Research Council via the INTERNET project.This is the final version of the article. It first appeared from IEEE via http://dx.doi.org/10.1109/JLT.2014.235405

A Principled Approach to Analyze Expressiveness and Accuracy of Graph Neural Networks

Graph neural networks (GNNs) have known an increasing success recently, with many GNN variants achieving state-of-the-art results on node and graph classification tasks. The proposed GNNs, however, often implement complex node and graph embedding schemes, which makes challenging to explain their performance. In this paper, we investigate the link between a GNN's expressiveness, that is, its ability to map different graphs to different representations, and its generalization performance in a graph classification setting. In particular , we propose a principled experimental procedure where we (i) define a practical measure for expressiveness, (ii) introduce an expressiveness-based loss function that we use to train a simple yet practical GNN that is permutation-invariant, (iii) illustrate our procedure on benchmark graph classification problems and on an original real-world application. Our results reveal that expressiveness alone does not guarantee a better performance, and that a powerful GNN should be able to produce graph representations that are well separated with respect to the class of the corresponding graphs