Effect of Coriaria arborea on seed banks during primary succession on Mt Tarawera, New Zealand

An experiment was conducted over two years to investigate the effect of Coriaria arborea, a native nitrogen-fixing shrub, on soil seed banks at sites representing a post-volcanic successional sequence on Mt Tarawera, New Zealand. The sites ranged from bare volcanic ash and lapilli substrate, through low-growing pre-Coriaria vegetation, to dense stands of Coriaria scrub. Soils (to a depth of 50 mm) under recently established Coriaria and older stands had more seedlings (1096 and 1585 seedlings 0.4 m-2, respectively) and species (37 and 45 species 0.4 m-2, respectively) emerge than where there was no Coriaria (243-320 seedlings 0.4 m-2, 14-25 species 0.4 m-2) and were the only soils with Coriaria seedlings. In total, 3488 seedlings representing 63 taxa were recorded. Seeds were still germinating after 24 months but rates declined markedly in the second year. For example, Coriaria reached a germination peak at 8 weeks but continued to germinate sporadically over the 2-year period. Tree species present in young forest within 0.5 km of the sites were absent. Establishment of Coriaria greatly accelerated an underlying trend of gradually increasing abundance and diversity of seeds in the soil with vegetation age. Adventive, wind-dispersed, and annual species were over-represented in the seed banks compared with the regional evergreen forest-dominated flora. These proportions are expected to decline as succession to forest gradually occurs

The use of chronosequences in studies of ecological succession and soil development

1. Chronosequences and associated space-for-time substitutions are an important and often necessary tool for studying temporal dynamics of plant communities and soil development across multiple time-scales. However, they are often used inappropriately, leading to false conclusions about ecological patterns and processes, which has prompted recent strong criticism of the approach. Here, we evaluate when chronosequences may or may not be appropriate for studying community and ecosystem development. 2. Chronosequences are appropriate to study plant succession at decadal to millennial time-scales when there is evidence that sites of different ages are following the same trajectory. They can also be reliably used to study aspects of soil development that occur between temporally linked sites over time-scales of centuries to millennia, sometimes independently of their application to shorter-term plant and soil biological communities. 3. Some characteristics of changing plant and soil biological communities (e.g. species richness, plant cover, vegetation structure, soil organic matter accumulation) are more likely to be related in a predictable and temporally linear manner than are other characteristics (e.g. species composition and abundance) and are therefore more reliably studied using a chronosequence approach. 4. Chronosequences are most appropriate for studying communities that are following convergent successional trajectories and have low biodiversity, rapid species turnover and low frequency and severity of disturbance. Chronosequences are least suitable for studying successional trajectories that are divergent, species-rich, highly disturbed or arrested in time because then there are often major difficulties in determining temporal linkages between stages. 5. Synthesis. We conclude that, when successional trajectories exceed the life span of investigators and the experimental and observational studies that they perform, temporal change can be successfully explored through the judicious use of chronosequences

Chapter 6 Living with landslides for Landslide Ecology

1. Human interactions with landslides have become more frequent and lethal as our populations expand into less stable terrain. This trend suggests that we must better understand what causes landslides and how to mitigate future damage. 2. Disturbances created by road construction, urban expansion, forestry, and agriculture are major contributors to anthropogenic landslides, and each has increased in frequency during the last several decades. 3. The field of landslide risk assessment is growing rapidly, and many new mapping and modeling tools are addressing how to predict landslide frequency and severity. Mitigation of landslide damage is also improving, particularly when new landslides follow patterns similar to previous ones. Despite a broad understanding oflandslide triggers and consequences, detailed predictions of specific events remain elusive, due to the stochastic nature of each landslide\u27s timing, pathway, and severity. 4. Biological tools are valuable additions to efforts to mitigate landslide damage. Biological protection of soil on slopes and restoration of species composition, food webs, and ecosystem processes ultimately must supplement technological approaches to achieve long-term slope stability because biological systems are generally more resilient than man-made structures

Competition and Facilitation: a Synthetic Approach to Interactions in Plant Communities

Interactions among organisms take place within a complex milieu of abiotic and biotic processes, but we generally study them as solitary phenomena. Complex combinations of negative and positive interactions have been identified in a number of plant communities. The importance of these two processes in structuring plant communities can best be understood by comparing them along gradients of abiotic stress, consumer pressure, and among different life stages, sizes, and densities of the interacting species. Here, we discuss the roles of life stage, physiology, indirect interactions, and the physical environment on the balance of competition and facilitation in plant communities

Health Technology Assessment (HTA) Case Studies : Factors Influencing Divergent HTA Reimbursement Recommendations in Australia, Canada, England, and Scotland

This document is the accepted manuscript version of the following article: Nicola Allen, Stuart R. Walker, Lawrence Liberti, and Sam Salek, ‘Health Technology Assessment (HTA) Case Studies: Factors Influencing Divergent HTA Reimbursement Recommendations in Australia, Canada, England, and Scotland’, Vol. 20 (3): 320-328, 2017, is made available under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives License CC BY NC-ND 4.0 ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited, and is not altered, transformed, or built upon in any way. The final, definitive version is available online at doi:https://doi.org/10.1016/j.jval.2016.10.014.OBJECTIVES: To evaluate the national regulatory, health technology assessment (HTA), and reimbursement pathways for public health care in Australia, Canada, England, and Scotland, to compare initial Canadian national HTA recommendations with the initial decisions of the other HTA agencies, and to identify factors for differing national HTA recommendations between the four HTA agencies. METHODS: Information from the public domain was used to develop a regulatory process map for each jurisdiction and to compare the HTA agencies' reimbursement recommendations. Medicines that were reviewed by all four agencies and received a negative recommendation from only one agency were selected as case studies. RESULTS: All four countries have a national HTA agency. Their reimbursement recommendations are guided by both clinical efficacy and cost-effectiveness, and the necessity for patient input. Their activities, however, vary because of different mandates and their unique political, social, and population needs. All have an implicit or explicit quality-adjusted life-year threshold. The seven divergent case studies demonstrate examples in which new medicine-indication pairs have been rejected because of uncertainties surrounding a range of factors including cost-effectiveness, comparator choice, clinical benefit, safety, trial design, and submission timing. CONCLUSIONS: The four HTA agencies selected for inclusion in this study share common factors, including a focus on clinical efficacy and cost-effectiveness in their decision-making processes. The differences in recommendations could be considered to be due to an individual agency's approach to risk perception, and the comparator choice used in clinical and cost-effectiveness studies.Peer reviewedFinal Accepted Versio

Is measurement uncertainty from sampling related to analyte concentration?

The contribution of sampling to the combined uncertainty of measurement is assessed using a combination of literature review and experimental determination of sampling variability in a range of foodstuffs in order to determine whether there is a consistent relationship between analyte level and proportion of variation attributable to sampling. Experimental determinations used the duplicate method, an economical method of assessing the relative contributions of sampling and analytical variability to the overall variance of results. The experimental work covered sampling of retail foodstuffs. 101 estimates of between-target, between-sampling, and within-sample variance were obtained. It is shown for the first time that sampling variance across the food sector appears to follow a Horwitz-like relationship sufficient to provide estimated between-sample standard deviation to within approximately an order of magnitude. The results from different methods of data processing for sampling uncertainty experiments are also compared. It is shown that for the data sets obtained experimentally in this study, log- transformation is of minor importance while the use of robust statistical methods can have greater but less predictable effects on estimated sampling variance

Pressure Induced Change in the Magnetic Modulation of CeRhIn5

We report the results of a high pressure neutron diffraction study of the heavy fermion compound CeRhIn5 down to 1.8 K. CeRhIn5 is known to order magnetically below 3.8 K with an incommensurate structure. The application of hydrostatic pressure up to 8.6 kbar produces no change in the magnetic wave vector qm. At 10 kbar of pressure however, a sudden change in the magnetic structure occurs. Although the magnetic transition temperature remains the same, qm increases from (0.5, 0.5, 0.298) to (0.5, 0.5, 0.396). This change in the magnetic modulation may be the outcome of a change in the electronic character of this material at 10 kbar.Comment: 4 pages, 3 figures include