In vitro autoradiography of hippocampal excitatory amino acid binding in aged Fischer 344 rats: Relationship to performance on the Morris water maze.

Tested young and aged Fischer 344 rats on the place and cue versions of the Morris water maze task. Although all of the young animals reached criterion within the 8-day testing period, the aged animals could be divided into 2 groups on the basis of their performance to criterion: achievers and nonachievers. Upon completion of the water maze testing, the animals were sacrificed, and their brains were processed for in vitro autoradiography of hippocampal excitatory amino acid receptors. Significant differences were found between the young and old rats in the levels of N-methyl-{d}-aspartate, CPP, kainate, and AMPA binding in subregions of the hippocampus. Despite the age-related decline in hippocampal glutamate receptors, no relationship was observed between the density or distribution of excitatory amino acid receptors and performance on the water maze task in the aged rats. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Selective exposure: Voter information preferences and the Watergate affair.

A survey of political preferences and attitudes conducted during the US Senate Watergate hearings of 1973 was used to examine hypotheses developed from selective exposure theory. Three groups of voters (N?=?82)—Richard Nixon supporters, George McGovern supporters, and undecideds—participated in a 3-wave panel survey conducted (a) just before the Watergate hearings started, (b) midway through the hearings, and (c) just before the end of the hearings. Responses that reflected interest in and attention to Watergate-related matters gave support to both the selective approach and avoidance components of the selective exposure hypothesis: The Nixon supporters reported less interest in and attention paid to Watergate-related matters than did members of the other groups. Responses to questions that probed for general knowledge about Watergate committee matters complemented the selective exposure analyses: Nixon supporters appeared to know less about the committee proceedings than the undecideds or McGovern supporters. Analyses of behavioral intentions and evaluations of the attitude object illustrated the importance of studying selective exposure effects. (30 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Data analysis for a dual-channel virus counter

A simple algorithm is presented for quantitative analysis of simultaneous events on a dual-channel flow cytometer designed specifically for virus counting. The algorithm, which is based on matrix analysis of burst lag times, was evaluated using baculovirus samples that had previously been quantified by the plaque titer method. The results indicated statistical reliability for the algorithm, with three of six samples yielding the same value, within error, for viruses per unit volume as the plaque titer. The other three samples yielded values within a factor approximately 2, which was deemed acceptable given the limitations of the plaque titer method.     

The use of a computer simulation to promote conceptual change: A quasi-experimental study

This mixed-methods investigation compared the effectiveness of three instructional approaches in achieving desired conceptual change among early childhood preservice teachers (n = 157). Each of the three treatments employed inquiry-based instruction on moon phases using data collected from: (1) the planetarium software program, Starry Night™, (2) nature observations and Starry Night™, or (3) nature observations alone. Data sources included drawings, intensive interviews, and a lunar shapes card sort. The data sets were analyzed via a constant comparative method in order to produce profiles of each participant’s pre- and post-instruction conceptual understandings of moon phases. Non-parametric tests of significance revealed that pre- to post-instruction gains were significant for all three treatments across all targeted concepts. The Starry Night™-Only treatment demonstrated statistically greater gains for sequencing moon phases than the other two treatments. However, there were no significant differences among the three treatments in regard to participants’ abilities to draw scientific moon shapes or in their conceptions of the causes of moon phases. Thus, the three treatments were equally effective in facilitating desired conceptual change.     

RedTweet: recommendation engine for reddit

Twitter and Reddit are two of the most popular social media sites used today. In this paper, we study the use of machine learning and WordNet-based classifiers to generate an interest profile from a user’s tweets and use this to recommend loosely related Reddit threads which the reader is most likely to be interested in. We introduce a genre classification algorithm using a similarity measure derived from WordNet lexical database for English to label genres for nouns in tweets. The proposed algorithm generates a user’s interest profile from their tweets based on a referencing taxonomy of genres derived from the genre-tagged Brown Corpus augmented with a technology genre. The top K genres of a user’s interest profile can be used for recommending subreddit articles in those genres. Experiments using real life test cases collected from Twitter have been done to compare the performance on genre classification by using the WordNet classifier and machine learning classifiers such as SVM, Random Forests, and an ensemble of Bayesian classifiers. Empirically, we have obtained similar results from the two different approaches with a sufficient number of tweets. It seems that machine learning algorithms as well as the WordNet ontology are viable tools for developing recommendation engine based on genre classification. One advantage of the WordNet approach is simplicity and no learning is required. However, the WordNet classifier tends to have poor precision on users with very few tweets.     

Assessment of musculoskeletal and other health complaints in female hospital staff

Musculoskeletal and other health complaints were investigated in a sample of 586 female hospital staff. Health complaints, including musculoskeletal pain, were assessed by the Ursin Health Inventory (UHI). Factor analyses of the UHI favoured a seven-factor solution in which musculoskeletal pain emerged as an independent factor of complaints. Other complaint factors could be labelled lower digestive, upper digestive, cardiorespiratory, allergy, cold/influenza and headache. Factor analyses of the extended version of the Nordic Questionnaire (NQ-EV), which focuses specifically on musculoskeletal pain from nine body areas, favoured a three-factor solution in which complaints from the upper back, low back and extremities emerged as the independent factors. Product-moment coefficients of correlation between factor-based sum scores in the two survey measures stated that the UHI factor 'musculoskeletal pain' and the NQ-EV factor 'upper back' were significantly correlated. This indicated an orientation of the UHI 'musculoskeletal pain' factor to pain in the upper part of the back. Only very moderate coefficients of correlation emerged between the NQ-EV factor scores and the remaining UHI scores. The results support the assumption that musculoskeletal complaints are not closely related to other types of health complaints, and that musculoskeletal complaints among female hospital staff should be assessed with separate items for upper back (neck/shoulders), low back and the extremities.     

Young children’s computer skills development from kindergarten to third grade

This investigation explores young children’s computer skills development from kindergarten to third grade using the Early Childhood Longitudinal Study–Kindergarten (ECLS–K) dataset. The sample size of the study was 8642 children. Latent growth curve modeling analysis was used as an analytical tool to examine the development of children’s computer skills using LISREL software version 8.80. Results indicated, not surprisingly, that the availability of a computer at home and a high socio-economic status were statistically significant predictors of children’s baseline computer skills in kindergarten. The availability of computers in kindergarten, however, was a statistically significant predictor of the development of children’s computer skills from kindergarten to third grade. Although there was no difference between girls and boys in their baseline computer skills in kindergarten, the rate of development in computer skills was higher for girls than boys. Results suggest that the availability of an adequate level of computers in kindergarten classrooms can help close the initial gap in children’s computer skills due to socio-economic status and lack of computer access prior to entering school. Supplying kindergarten classrooms with adequate computers could positively contribute to children’s long-term development of computer skills.     

Fractional biometrics: safeguarding privacy in biometric applications

This paper presents a biometric system solution that “masks” a fraction of a person’s biometric image before submission, to reduce the possibility of forgery and collusion. A prototype system was constructed for the fingerprint biometric and tested in three security scenarios. It is shown that implementing the fractional biometric system does not significantly affect accuracy. We provide theoretical security analysis on the guessing entropy of a Fractional Template and the security against collusion. We demonstrate that by masking above 50% of the biometric features, we achieve a sufficient mix of security, robustness and accuracy to warrant further study. When 75% of the features are masked, we found that the theoretical guessing entropy is 42 bits, and we found that, on average, 5 authenticators had to collude before the system would be compromised.     

Assessing the attributes of high-density Eucalyptus globulus stands using airborne laser scanner data

This article presents an airborne Light Detection and Ranging (LiDAR)-based method to extract interesting stand attributes for forest management in high-density Eucalyptus globulus Labill. plantations. An adaptive morphological filter (AMF) for classifying terrain LiDAR points in forested areas is used to classify LiDAR points; canopy cover (CC), number of LiDAR-detected trees per hectare (N _LD) and individual tree height (h _tree) were calculated using the canopy height model (CHM); and several statistics and metrics extracted from the CHM and the normalized height of the LiDAR data cloud (NHD) were incorporated into the linear and multiplicative models for estimating mean height (H _m), dominant height (H _d), mean diameter (d _m), quadratic mean diameter (d _g), number of stems per hectare (N), basal area (G) and volume (V). The height accuracy results of the LiDAR-derived digital terrain model (DTM), root mean square error (RMSE)?=?0.303 m, revealed that the developed filter behaved well. The values of the RMSE for CC, N _LD and h _tree were 13.2%, 733.3 stems ha^–1 and 1.91 m, respectively. The regressions explained 78% of the variance in ground-truth values for H _m (RMSE?=?1.33 m); 92% for H _d (RMSE?=?1.18 m); 71% for d _m (RMSE?=?1.68 cm); 73% for d _g (RMSE?=?1.66 cm); 49% for N (RMSE?=?667 stems ha^–1); 78% for G (RMSE?=?5.30 m² ha^–1); and 81% for V (RMSE?=?53.6 m³ ha^–1).     

Optimization of a Nanoparticle Suspension for Freeze Casting

Poly(acrylic acid) (PAA) dispersant concentration, suspension pH, and Al₂O₃ solids loading effects on PAA adsorption onto Al₂O₃ nanoparticles were studied; the stability and rheology of the Al₂O₃ nanoparticle suspensions were examined. The most desirable suspension conditions were 7.5–9.5 for pH and 2.00–2.25 wt% of Al₂O₃ for the PAA concentration. Electrical double-layer thickness and PAA adsorption layer thickness comparison showed that electrosteric stabilization was dominant. 45.0 vol% Al₂O₃ solids loading can be achieved for freeze casting. The maximum solids loading was predicted to be 50.7 vol%. The freeze-cast sample showed that pre-rest before freezing was critical for achieving desirable microstructures.