Microbial control of diamondback moth,Plutella xylostella L. (Lepidoptera: Yponomeutidae) using bacteria (Xenorhabdus nematophila) and its metabolites from the entomopathogenic nematode Steinernema carpocapsae

Cells and cell-free solutions of the culture filtrate of the bacterial symbiont, Xenorhabdus nematophila taken from the entomopathogenic nematode Steinernema carpocapsae in aqueous broth suspensions were lethal to larvae of the diamondback moth Plutella xylostella. Their application on leaves of Chinese cabbage indicated that the cells can penetrate into the insects in the absence of the nematode vector. Cell-free solutions containing metabolites were also proved as effective as bacterial cells suspension. The application of aqueous suspensions of cells of X. nematophila or solutions containing its toxic metabolites to the leaves represents a possible new strategy for controlling insect pests on foliage.     

Contraction force specificity and its relationship to functional performance

Abstract

Best practice for improving strength and power through resistance strength training has been the subject of much research and subsequent conjecture. Much of the conjecture can be attributed to methodological discrepancies. The type of dynamometry used in testing, the training experience of research participants, the specific technique employed in a lift, and the methods of collection and calculation all impact on the final variables of interest. This review examines contraction force specificity by first addressing the methodological issues surrounding our interpretation of the results. Then we address the kinematics and kinetics associated with single and multiple repetitions in relation to the development of strength, power, and functional performance. This discussion provides the delimitations for analysis of subsequent training studies. Finally, recommendations are formulated with the aim of assisting assessment and training practice as well as providing directions for future research. The results of this review suggest that the enhancements in performance resulting from resistance training are context specific in experienced resistance-trained participants. Thus, specific conditioning could be required to achieve improvements in functional performance in this group.     

Effect of Optimized and Standard Cycle Ergometry on VO2max in Trained Cyclists and Runners

Abstract

This study contrasted prepractice modeling with either the perceptual component (perceptual modeling) or the motor component (movement pattern) of a coincident-timing task to determine whether experiencing the modalities singly or in combination enhanced timing performance on initiation of active practice. The motor component was a 60-cm right-to-left arm movement coincident with the illumination of lights on a Bassin timer runway to displace a barrier as the final runway light was illuminated. Four groups were compared (n = 12 per group). A perceptual modeling group passively viewed stimulus runway lights prior to attempting the task. A motoric modeling group viewed a videotape prior to practice of a model performing the motor component of the skill with zero timing error. A perceptual modeling plus motoric modeling group experienced both modeling modalities prior to performance. Finally, a no modeling group simply initiated practice on the task without modeling. Results indicated that the groups experiencing perceptual modeling initiated practice with significantly less average timing error and variability. Thus, perceptual modeling appeared to be at least as important as motoric modeling as a source of prepractice information to make available to a learner to optimize coincident-timing skill acquisition.     

The role of invitations to parents in the completion of a child’s home reading challenge

The role parents can play in supporting early reading attainment is well documented. There is still, however, a need to understand what motivates parents to become involved in reading at home with their child. Past research, based upon correlational studies, has mixed findings regarding the influence of the teacher and the child on parents’ motivation at home. Through two quasi-experiments, the present study explored the influence of teacher invitations in Kindergarten classes, and child invitations in Grade 2 classes on completion rates of a home reading challenge. The completion of the home reading among families was investigated across two metropolitan schools in Sydney, Australia. Both of the interventions resulted in significantly higher completion rates compared to control groups (teacher invitations: d = .68; child invitations: d = .73). This paper adds to existing research by providing a clearer picture of the cause-and-effect relationship between schools’ use of invitations to facilitate children’s home reading.     

Our shrinking ozone layer

Depletion of the Earth’s ozone layer is one of the major environmental concerns for the new millennium having serious implications on human health, agriculture and climate. In the past decades, research by the international scientific community has been directed towards understanding the impact of human interference on the Earth’s atmosphere. The importance of ozone radiation absorption in the atmosphere and the general kinetics of the stratospheric ozone depletion mechanisms have motivated many theoretical and experimental studies on various chemical species. The distribution of ozone and other trace gases in the atmosphere is governed by the complex interaction of dynamical, chemical and radiative processes. This article concentrates on the basic concepts underlying the problems that may be faced by humankind due to reduction in the ozone layer in coming decades, and the ways in which the scientific community can contribute to predicting and remediating these effects through design of international treaties, regulations and amendments.