Polyandrous Mexican Fruit Flies: Second Male Paternity and Biological Attributes of Transgenic Strains

Anastrepha ludens (Diptera: Tephritidae), is a damaging agricultural pest. Currently, the Sterile Insect Technique (SIT) is used as part of its control. The SIT consists of the mass-rearing, sterilization, and release of insects in target areas. Sterile males mate with wild females, and prevent them from laying fertile eggs. However, even if females mate with sterile males, they can then remate with a second male. If this second male is wild, then this could reduce the efficiency of the SIT by producing viable offspring. The amount of progeny produced by second males (P2 values) for A. ludens is unknown. Here, we evaluated the biological attributes, mating competitiveness, and the proportion of male paternity gained by the second male, using strains that carry fluorescent marker genes and can be potentially used to develop transgenic sexing strains. Furthermore, the transgenic strains were irradiated, to test their ability to induce sterility in females. We found that the 443-G strain had significantly higher larval survival than the 419-R strain. No significant difference was found between the two strains in their mating probability with wild females. We found P2 values between 67 and 74% for the 419-R and the 443-G strain, respectively. Second male sperm precedence only decreased slightly after 12 days, suggesting that sperm from the first and second male is not mixing with time, but rather the second male’s sperm prevails. Furthermore, sterile 443-G males induced significantly higher sterility in females than sterile males from the 419-R strain. The apparent lower ability of the 443-G strain to inhibit female remating should be further investigated. Knowledge of the pre and postcopulatory performance of transgenic strains will help in understanding their potential for control.

Is Kindergarten Ability Group Placement Biased? New Data, New Methods, New Answers

Half of kindergarten teachers split children into higher and lower ability groups for reading or math. In national data, we predicted kindergarten ability group placement using linear and ordinal logistic regression with classroom fixed effects. In fall, test scores were the best predictors of group placement, but there was bias favoring girls, high-SES (socioeconomic status) children, and Asian Americans, who received higher placements than their scores alone would predict. Net of SES, there was no bias against placing black children in higher groups. By spring, one third of kindergartners moved groups, and high-SES children moved up more than their score gains alone would predict. Teacher-reported behaviors (e.g., attentiveness, approaches to learning) helped explain girls’ higher placements, but did little to explain the higher placements of Asian American and high-SES children.

Select relevant moderators using Bayesian regularized meta-regression

When analyzing a heterogeneous body of literature, there may be many potentially relevant between-studies differences. These differences can be coded as moderators, and accounted for using meta-regression. However, many applied meta-analyses lack the power to adequately account for multiple moderators, as the number of studies on any given topic is often low. The present study introduces Bayesian Regularized Meta-Analysis (BRMA), an exploratory algorithm that can select relevant moderators from a larger number of candidates. This approach is suitable when heterogeneity is suspected, but it is not known which moderators most strongly influence the observed effect size. We present a simulation study to validate the performance of BRMA relative to state-of-the-art meta-regression (RMA). Results indicated that BRMA compared favorably to RMA on three metrics: predictive performance, which is a measure of the generalizability of results, the ability to reject irrelevant moderators, and the ability to recover population parameters with low bias. BRMA had slightly lower ability to detect true effects of relevant moderators, but the overall proportion of Type I and Type II errors was equivalent to RMA. Furthermore, BRMA regression coefficients were slightly biased towards zero (by design), but its estimates of residual heterogeneity were unbiased. BRMA performed well with as few as 20 studies in the training data, suggesting its suitability as a small sample solution. We discuss how applied researchers can use BRMA to explorate between-studies heterogeneity in meta-analysis.

Efficacy of slightly acidic electrolyzed water on inactivation of Cronobacter sakazakii and biofilm cell

The disinfection efficacy and mechanism of slightly acid electrolyzed water (SAEW) on Cronobacter sakazakii were investigated. SAEW solutions in three concentrations were carried on C. sakazakii which decreased in a range of 23%-55% in 2 minutes. The propidium iodide (PI) uptake and electronic microscopy (SEM) images indicated that SAEW treatment damaged cell integrity and changed membrane permeability with leaking nucleic acid (109.7%), intercellular protein (692.3%) and K + (53.6%). It was accompanied with lower ability of biofilm formation. SAEW treatment reduced the activity of SOD and CAT from 100.73 U/mgprot and 114.18 U/mgprot to 50.03 U/mgprot and 50.13 U/mgprot, respectively. It lowered down the gene expression of response regulator (katG, rpoS, phoP, glpK,dacC and CSK29544_RS05515 ) which made C. sakazakii failed to repair osmotic stress-induced damage and inhibited their biofilm formation. These findings provide an understanding of associations between bacterial genotype and phenotype induced by SAEW.

Teachers' Predictions and Pupil Achievement in School Certificate

<p>This thesis examines the estimates of pupils' performances in School Certificate made by teachers at Hutt Valley High School over a six year period. It aims to assess the degree of accuracy of teacher predictions, in particular at the pass/fail boundary, and to identify and evaluate the relative importance of some correlates of accurate prediction. The data for this study is taken from school records showing for each class the name of the teacher and the estimated and achieved marks of each pupil in School Certificate for the period 1973 to 1978. The statistical analyses include the calculation of the Pearson Product-Moment Correlation Coefficient between the estimated and achieved marks of pupils in English, Mathematics, Science and French. Expectancy tables are provided to give greater detail of the accuracy of teacher's estimates at different points across the mark range. A multiple regression analysis is carried out in order to identify and evaluate the relative importance of some correlates of accurate prediction. The statistical section concludes with a summary analysis of the data from the subjects for the year following the major analysis. The results of the study show that the correlations between the estimated and achieved marks are greater in Mathematics and French than in English and Science, however, the estimated and achieved class means across subjects show greatest agreement in English and least agreement in Mathematics. Whilst variations across subjects and across years occur, in general teachers show a tendency to underestimate pupils at the upper end of the ability range and overestimate the marks of pupils at other points of the scale. A movement of approximately 16.5% across the pass/fail boundary was observed when comparing the estimated and achieved marks of pupils. The study also concludes that the only factor to reveal a substantial and systematic link with the quality of teachers' predictions was the ability level of the class under analysis - teachers were generally more able to predict the results of their pupils for higher ability than lower ability classes (English excepted).</p>

Teachers' Predictions and Pupil Achievement in School Certificate

<p>This thesis examines the estimates of pupils' performances in School Certificate made by teachers at Hutt Valley High School over a six year period. It aims to assess the degree of accuracy of teacher predictions, in particular at the pass/fail boundary, and to identify and evaluate the relative importance of some correlates of accurate prediction. The data for this study is taken from school records showing for each class the name of the teacher and the estimated and achieved marks of each pupil in School Certificate for the period 1973 to 1978. The statistical analyses include the calculation of the Pearson Product-Moment Correlation Coefficient between the estimated and achieved marks of pupils in English, Mathematics, Science and French. Expectancy tables are provided to give greater detail of the accuracy of teacher's estimates at different points across the mark range. A multiple regression analysis is carried out in order to identify and evaluate the relative importance of some correlates of accurate prediction. The statistical section concludes with a summary analysis of the data from the subjects for the year following the major analysis. The results of the study show that the correlations between the estimated and achieved marks are greater in Mathematics and French than in English and Science, however, the estimated and achieved class means across subjects show greatest agreement in English and least agreement in Mathematics. Whilst variations across subjects and across years occur, in general teachers show a tendency to underestimate pupils at the upper end of the ability range and overestimate the marks of pupils at other points of the scale. A movement of approximately 16.5% across the pass/fail boundary was observed when comparing the estimated and achieved marks of pupils. The study also concludes that the only factor to reveal a substantial and systematic link with the quality of teachers' predictions was the ability level of the class under analysis - teachers were generally more able to predict the results of their pupils for higher ability than lower ability classes (English excepted).</p>

The Impact of the HydroxyMethylCytosine epigenetic signature on DNA structure and function

We present a comprehensive, experimental and theoretical study of the impact of 5-hydroxymethylation of DNA cytosine. Using molecular dynamics, biophysical experiments and NMR spectroscopy, we found that Ten-Eleven translocation (TET) dioxygenases generate an epigenetic variant with structural and physical properties similar to those of 5-methylcytosine. Experiments and simulations demonstrate that 5-methylcytosine (mC) and 5-hydroxymethylcytosine (hmC) generally lead to stiffer DNA than normal cytosine, with poorer circularization efficiencies and lower ability to form nucleosomes. In particular, we can rule out the hypothesis that hydroxymethylation reverts to unmodified cytosine physical properties, as hmC is even more rigid than mC. Thus, we do not expect dramatic changes in the chromatin structure induced by differences in physical properties between d(mCpG) and d(hmCpG). Conversely, our simulations suggest that methylated-DNA binding domains (MBDs), associated with repression activities, are sensitive to the substitution d(mCpG) ➔ d(hmCpG), while MBD3 which has a dual activation/repression activity is not sensitive to the d(mCpG) d(hmCpG) change. Overall, while gene activity changes due to cytosine methylation are the result of the combination of stiffness-related chromatin reorganization and MBD binding, those associated to 5-hydroxylation of methylcytosine could be explained by a change in the balance of repression/activation pathways related to differential MBD binding.

Rapid Identification of Escherichia coli Colistin-Resistant Strains by MALDI-TOF Mass Spectrometry

Colistin resistance is one of the major threats for global public health, requiring reliable and rapid susceptibility testing methods. The aim of this study was the evaluation of a MALDI-TOF mass spectrometry (MS) peak-based assay to distinguish colistin resistant (colR) from susceptible (colS) Escherichia coli strains. To this end, a classifying algorithm model (CAM) was developed, testing three different algorithms: Genetic Algorithm (GA), Supervised Neural Network (SNN) and Quick Classifier (QC). Among them, the SNN- and GA-based CAMs showed the best performances: recognition capability (RC) of 100% each one, and cross validation (CV) of 97.62% and 100%, respectively. Even if both algorithms shared similar RC and CV values, the SNN-based CAM was the best performing one, correctly identifying 67/71 (94.4%) of the E. coli strains collected: in point of fact, it correctly identified the greatest number of colS strains (42/43; 97.7%), despite its lower ability in identifying the colR strains (15/18; 83.3%). In conclusion, although broth microdilution remains the gold standard method for testing colistin susceptibility, the CAM represents a useful tool to rapidly screen colR and colS strains in clinical practice.

Reporting Verbs and Related Syntactic Choices in Students' Theses: A Study of Two Disciplines

Adopting Hyland's (2002) framework of reporting words (RVs), the paper investigates the use of RVs in Master's theses written in English by students of two disciplines, Economics and Management and Natural Resources. The data were drawn from two sub-corpora, each consisting of 82 Literature Reviews, where other authors' research is summarised and commented on. Besides determining the most frequent communicative functions, in this paper, the RVs are further analysed in terms of the verb tense, voice, and subject-agent. The findings revealed significant differences between the two disciplines. In the former, most RVs were in the present active with named-author as the subject, conveying a neutral attitude towards the reported message and neutrally summarising previous research outcomes. Most RVs were in the past tense in the latter, reporting on past research procedures or outcomes. The findings reveal infrequent use of evaluative or critical verbs. Each discipline's predominant choice may suggest writers' lower ability to highlight the cited sources' direct relevance to their research. The study hopes to contribute to the efficacy of teaching English for Academic Purposes to non-native speakers. It has pedagogical implications for academic writing in both undergraduate and postgraduate courses at non-philological tertiary education institutions.

Highly Porous Fluorapatite/β-1,3-Glucan Composite for Bone Tissue Regeneration: Characterization and In-Vitro Assessment of Biomedical Potential

A novel fluorapatite/glucan composite (“FAP/glucan”) was developed for the treatment of bone defects. Due to the presence of polysaccharide polymer (β-1,3-glucan), the composite is highly flexible and thus very convenient for surgery. Its physicochemical and microstructural properties were evaluated using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), mercury intrusion, mechanical testing and compared with the reference material, which was a hydroxyapatite/glucan composite (“HAP/glucan”) with hydroxyapatite granules (HAP) instead of FAP. It was found that FAP/glucan has a higher density and lower porosity than the reference material. The correlation between the Young’s modulus and the compressive strength between the materials is different in a dry and wet state. Bioactivity assessment showed a lower ability to form apatite and lower uptake of apatite-forming ions from the simulated body fluid by FAP/glucan material in comparison to the reference material. Moreover, FAP/glucan was determined to be of optimal fluoride release capacity for osteoblasts growth requirements. The results of cell culture experiments showed that fluoride-containing biomaterial was non-toxic, enhanced the synthesis of osteocalcin and stimulated the adhesion of osteogenic cells.