Macquarie University

About: Macquarie University is a education organization based out in Sydney, New South Wales, Australia. It is known for research contribution in the topics: Population & Laser. The organization has 14075 authors who have published 47673 publications receiving 1416184 citations. The organization is also known as: Macquarie uni.

Kinetic mechanism for the reaction between methanol and water over a cu-zno-al2o3 catalyst

Abstract: The steam reforming of methanol over a Cu/ZnO/Al 2 O 3 catalyst has been investigated. The reaction yields carbon dioxide and hydrogen in the ratio of one to three, with small amounts of dimethyl ether and carbon monoxide being produced at high conversion. Comparison of the rates of methanol dehydrogenation and of steam reforming over the same catalyst indicate that steam reforming proceeds via dehydrogenation to methyl formate. Methyl formate then hydrolyses to formic acid which decomposes to carbon dioxide and hydrogen. Detailed studies of the kinetics of the reactions show that methanol dehydrogenation controls the rate of steam reforming. Langmuir-Hinshelwood modelling indicates that hydrogen extraction from adsorbed methoxy groups is rate determining to the overall processes.

Least‐Cost Input Mixtures of Water and Nitrogen for Photosynthesis

Abstract: In microeconomics, a standard framework is used for determining the optimal input mix for a two‐input production process. Here we adapt this framework for understanding the way plants use water and nitrogen (N) in photosynthesis. The least‐cost input mixture for generating a given output depends on the relative cost of procuring and using nitrogen versus water. This way of considering the issue integrates concepts such as water‐use efficiency and photosynthetic nitrogen‐use efficiency into the more inclusive objective of optimizing the input mix for a given situation. We explore the implications of deploying alternative combinations of leaf nitrogen concentration and stomatal conductance to water, focusing on comparing hypothetical species occurring in low‐ versus high‐humidity habitats. We then present data from sites in both the United States and Australia and show that low‐rainfall species operate with substantially higher leaf N concentration per unit leaf area. The extra protein reflected i...

A meta-analysis of plant responses to light intensity for 70 traits ranging from molecules to whole plant performance.

Abstract: By means of meta-analyses we determined how 70 traits related to plant anatomy, morphology, chemistry, physiology, growth and reproduction are affected by daily light integral (DLI; mol photons m-2 d-1 ). A large database including 500 experiments with 760 plant species enabled us to determine generalized dose-response curves. Many traits increase with DLI in a saturating fashion. Some showed a more than 10-fold increase over the DLI range of 1-50 mol m-2 d-1 , such as the number of seeds produced per plant and the actual rate of photosynthesis. Strong decreases with DLI (up to three-fold) were observed for leaf area ratio and leaf payback time. Plasticity differences among species groups were generally small compared with the overall responses to DLI. However, for a number of traits, including photosynthetic capacity and realized growth, we found woody and shade-tolerant species to have lower plasticity. We further conclude that the direction and degree of trait changes adheres with responses to plant density and to vertical light gradients within plant canopies. This synthesis provides a strong quantitative basis for understanding plant acclimation to light, from molecular to whole plant responses, but also identifies the variables that currently form weak spots in our knowledge, such as respiration and reproductive characteristics.

Improved Self-Control: The Benefits of a Regular Program of Academic Study

Abstract: Academic examination stress impairs regulatory behavior by consuming self-control strength (Oaten & Cheng, 2005). In this study, we tested whether a study intervention program, a form of repeated practice of self-control, could improve regulatory strength and dampen the debilitating effects of exam stress. We assessed 2 cohorts at baseline and again at the commencement of exams. Without any intervention, we replicated our previous findings of deteriorations in regulatory behaviors at exam time. Students receiving the study program, however, showed significant improvement in self-regulatory capacity as shown by an enhanced performance on a visual tracking task following a thought-suppression task. During examinations, these participants also reported significant decreases in smoking, alcohol, and caffeine consumption and an increase in healthy eating, emotional control, maintenance of household chores, attendance to commitments, monitoring of spending, and an improvement in study habits. Hence, the study program not only overcame deficits caused by exam stress but actually led to improvements in self-control even during exam time.