Literacy Practices and Schooling: A Case Study from Mozambique

A novel approach to the assessment of literacy is used to tackle the issue of effectiveness of years of schooling. The dichotomy inherent in the literacy rate is rejected in favor of a " practice-based" approach, which considers literacy as a multifaceted phenomenon as advocated in anthropological and economic research. Primary data collected in the poorest region in Mozambique suggest that years of schooling have a differentiated impact on acquired literacy practices of adults. Results that are robust to different specifications are reported. © 2011 Elsevier Ltd

Deep Imaging of the Double Quasar 0957+561: New Constraints on H_0

We present new results from extremely deep, high-resolution images of the field around the double quasar QSO 0957+561. A possible gravitational arc system near the double quasar has recently been reported, which, if real, would set strong constraints on determinations of the Hubble constant from the time delay in the double quasar. We find that both the morphology and the colors of the claimed arc systems suggest that they are chance alignments of three and two different objects, and not gravitationally lensed arcs. Hence, the constraints on $H_0$-determinations from the arcs are not valid. Also, a small group of galaxies at $z=0.5$ near the line-of-sight which was required to have a very large mass in the physically interesting arc models, is most likely insignificant. From our deep images we are able to use weak lensing of faint background galaxies in the field to map the gravitational potential in the main cluster. This sets new constraints on determinations of $H_0$. We find that the Hubble constant is constrained to be less than 70km/(s Mpc), if the time delay between the two images of the QSO is equal to or larger than 1.1 years.Comment: (uuencoded and compressed postscipt including 3 figures); 14 page

The environments of intermediate-redshift QSOs: 0.3 < z < 0.7

An angular correlation of low significance (2 sigma) is observed between 0.3 < z < 0.5 QSOs and V < 23 galaxies. Overall, the cross-correlation function between 82 intermediate-redshift (0.3 < z < 0.7), X-ray selected QSOs and V < 24 galaxies is investigated, but no signal is detected for the z > 0.5 QSOs. After converting to an excess of galaxies physically associated with the QSO, this lack of strong correlation is shown to be consistent with the clustering of normal galaxies at the same moderate redshifts. Combined with previous observations, these results imply that the environments of radio-quiet QSOs do not undergo significant evolution with respect to the galaxy population over a wide range of redshifts (0 < z < 1.5). This is in marked contrast to the rapid increase in the richness of the environments associated with radio-loud QSOs over the same redshift range.Comment: 12 pages, 8 figures, MNRAS TeX macro, to appear to MNRA

The Efficiency of Retrieval Practice as a Function of Spacing and Intrinsic Value in Young and Older Adults

Two powerful methods of improving memory in young and older adults are spacing and testing. The spacing effect refers to the observation that learning material with intervening material between study events, compared to no intervening material between study events, improves long-term memory. The testing effect refers to the finding that retrieving information from memory: via testing) improves memory over merely restudying the information. A combination of the two methods is referred to as spaced retrieval practice, which is the focus of the present dissertation. There were three specific questions addressed. First, how is the function relating continued retrieval practice and long-term memory modulated by the intervening spacing interval: i.e., lag)? Second, how does this function differ between young and healthy older adults given age-related changes in working memory capacity and forgetting rate across short delays? Third, to what extent does the individual\u27s motivation to learn specific information influence the benefit of spaced retrieval practice? To address the first two questions, Experiment 1 examined the benefit of continued retrieval practice during the acquisition phase on a final cued recall test as a function of lag, retention interval, and age. Participants studied word pairs: e.g., QUEEN - lady) during an initial acquisition phase and were tested on those pairs one, three or five times: e.g., QUEEN - ?????) which were separated by short or long lags: i.e., 1 vs. 3 intervening items). Following either a short or long retention interval, participants completed a final cued recall test. The results revealed that continued testing in the short lag condition led to consistent increases in retention, whereas continued testing in the long lag condition led to increasingly smaller benefits in retention for both age groups. Analysis of final test response latency revealed a different pattern than that observed in accuracy such that young adults benefited from continued testing in the long lag condition but not the short lag condition, and older adults benefited from continued testing in the short lag condition but not the long lag condition. Experiment 2 extended the first experiment by examining the benefit of massed: testing without intervening material) versus spaced: Lag 4) retrieval practice across age groups. Young adults benefited from continued testing in both the massed and spaced conditions, whereas older adults showed a selective benefit of continued testing in the spaced condition. Again, analysis of response latency on the final test revealed a different pattern of results such that young adults benefited uniquely from continued testing in the spaced condition but not the massed condition, and older adults benefited from continued testing in both conditions. In pursuit of the third aim regarding the role of participant motivation on the spacing effect, Experiment 3 examined the benefit of retrieval practice for paired associates assigned either a low point value or a high point value. Participants were asked to earn as many points as possible by successfully retrieving items on the final test. Results revealed the predicted benefit of lag and point value on final test accuracy for both young and older adults with no interaction between these two factors. These results suggest that the manipulation of point value effectively modulated participant motivation to learn and retain the paired associates similarly across massed and spaced retrieval conditions. Emphasis on retention: i.e., conditional final test performance) revealed a pattern of results that diverged from past studies such that young and older adults benefited similarly from spaced retrieval when differences in acquisition performance were minimized: Experiment 1). Moreover, age-related differences in refreshing: Experiment 2) and attention: Experiment 3) were implicated as contributing factors to final test performance above and beyond age differences in acquisition accuracy. Discussion focuses on the role of desirable difficulty in producing the benefits of lag, spacing and testing, along with methodological insights into different measures of memory integrity: response latency and accuracy)