Dynamics and spatio-temporal variability of environmental factors in Eastern Australia using functional principal component analysis

This paper introduces a new technique in ecology to analyze spatial and temporal variability in environmental variables. By using simple statistics, we explore the relations between abiotic and biotic variables that influence animal distributions. However, spatial and temporal variability in rainfall, a key variable in ecological studies, can cause difficulties to any basic model including time evolution. The study was of a landscape scale (three million square kilometers in eastern Australia), mainly over the period of 19982004. We simultaneously considered qualitative spatial (soil and habitat types) and quantitative temporal (rainfall) variables in a Geographical Information System environment. In addition to some techniques commonly used in ecology, we applied a new method, Functional Principal Component Analysis, which proved to be very suitable for this case, as it explained more than 97% of the total variance of the rainfall data, providing us with substitute variables that are easier to manage and are even able to explain rainfall patterns. The main variable came from a habitat classification that showed strong correlations with rainfall values and soil types. © 2010 World Scientific Publishing Company.

Does calibration reduce variability in the assessment of accounting learning outcomes?

Reliable, consistent assessment process that produces comparable assessment grades between assessors and institutions is a core activity and an ongoing challenge with which universities have failed to come to terms. In this paper, we report results from an experiment that tests the impact of an intervention designed to reduce grader variability and develop a shared understanding of national threshold learning standards by a cohort of reviewers. The intervention involved consensus moderation of samples of accounting students’ work, with a focus on three research questions. First, what is the quantifiable difference in grader variability on the assessment of learning outcomes in ‘application skills’ and ‘judgement’? Second, does participation in the workshops lead to reduced disparity in the assessment of the students’ learning outcomes in ‘application skills’ and ‘judgement’? Third, does participation in the workshops lead to greater confidence by reviewers in their ability to assess students’ skills in application skills and judgement? Our findings suggest consensus moderation does reduce variability across graders and also builds grader confidence.

Interobserver Variability in the Treatment of Little Finger Metacarpal Neck Fractures

Purpose To address the null hypothesis that surgeons shown radiographs of little finger metacarpal neck fractures with measured fracture angulation would recommend surgery as often as surgeons shown unmarked radiographs. Methods Members of the Science of Variation Group, an international collaboration of fully trained orthopedic and trauma surgeons, were asked to review 20 little finger metacarpal neck fracture cases, which included a vignette and 3 high-quality radiographs. Members were then randomized to review radiographs with or without measured fracture angulation on the lateral view and select operative or nonoperative management. Results Surgeons shown radiographs with measured angulation were more likely to recommend surgery, and there was less variability among these surgeons, particularly for fractures with less angular deformity. Conclusions Measured fracture angulation has a small but significant influence on treatment recommendations for little finger metacarpal neck fractures.

Breeding short-tailed shearwaters buffer local environmental variability in south-eastern Australia by foraging in Antarctic waters

BACKGROUND: Establishing patterns of movements of free-ranging animals in marine ecosystems is crucial for a better understanding of their feeding ecology, life history traits and conservation. As central place foragers, the habitat use of nesting seabirds is heavily influenced by the resources available within their foraging range. We tested the prediction that during years with lower resource availability, short-tailed shearwaters (Puffinus tenuirostris) provisioning chicks should increase their foraging effort, by extending their foraging range and/or duration, both when foraging in neritic (short trips) and distant oceanic waters (long trips). Using both GPS and geolocation data-loggers, at-sea movements and habitat use were investigated over three breeding seasons (2012-14) at two colonies in southeastern Australia. RESULTS: Most individuals performed daily short foraging trips over the study period and inter-annual variations observed in foraging parameters where mainly due to few individuals from Griffith Island, performing 2-day trips in 2014. When performing long foraging trips, this study showed that individuals from both colonies exploited similar zones in the Southern Ocean. The results of this study suggest that individuals could increase their foraging range while exploiting distant feeding zones, which could indicate that short-tailed shearwaters forage in Antarctic waters not only to maintain their body condition but may also do so to buffer against local environmental stochasticity. Lower breeding performances were associated with longer foraging trips to distant oceanic waters in 2013 and 2014 indicating they could mediate reductions in food availability around the breeding colonies by extending their foraging range in the Southern Ocean. CONCLUSIONS: This study highlights the importance of foraging flexibility as a fundamental aspect of life history in coastal/pelagic marine central place foragers living in highly variable environments and how these foraging strategies are use to buffer this variability.

Foraging strategies and reproductive success in two sympatric seabird species: influence of environmental variability

 This work focused on flexibility in foraging strategies in little penguins and short-tailed shearwaters, which represents an important mechanism enabling them to cope with highly dynamic ecosystems and provides a buffer against spatial and temporal changes in prey availability over the breeding period.

Assessing spatio-temporal hydrologic variability: a case-study in western Victoria

This research explored spatial and temporal variability in the relationships between land cover, topography, and climate on streamflows and wetland extents in western Victoria.

Holocene record of Tuggerah Lake estuary development on the Australian east coast: sedimentary responses to sea-level fluctuations and climate variability

We investigated the Holocene palaeo-environmental record of the Tuggerah Lake barrier estuary on the south-east coast of Australia to determine the influence of local, regional and global environmental changes on estuary development. Using multi-proxy approaches, we identified significant down-core variation in sediment cores relating to sea-level rise and regional climate change. Following erosion of the antecedent land surface during the post-glacial marine transgression, sediment began to accumulate at the more seaward location at ~8500. years before present, some 1500. years prior to barrier emplacement and ~4000. years earlier than at the landward site. The delay in sediment accumulation at the landward site was a consequence of exposure to wave action prior to barrier emplacement, and due to high river flows of the mid-Holocene post-barrier emplacement. As a consequence of the mid-Holocene reduction in river flows, coupled with a moderate decline in sea-level, the lake experienced major changes in conditions at ~4000. years before present. The entrance channel connecting the lake with the ocean became periodically constricted, producing cyclic alternation between intervals of fluvial- and marine-dominated conditions. Overall, this study provides a detailed, multi-proxy investigation of the physical evolution of Tuggerah Lake with causative environmental processes that have influenced development of the estuary.

Step by step analyzing, modeling and simulation of single and double array PV system in different environmental variability

This research analyses the mathematical model of the PV array with all the parameters involved, in the sequential steps. Then it is going to simulate the I-V and P-V characteristics of PV array in different climatology conditions, by using both MATLAB M-file and Simulink. Finally the capability of this method is demonstrated in simulated results, which are performed for both Single and Double Array PV system.

Variability of sedimentary organic carbon in patchy seagrass landscapes

Seagrass ecosystems, considered among the most efficient carbon sinks worldwide, encompass a wide variety of spatial configurations in the coastal landscape. Here we evaluated the influence of the spatial configuration of seagrass meadows at small scales (metres) on carbon storage in seagrass sediments. We intensively sampled carbon stocks and other geochemical properties (δ(13)C, particle size, depositional fluxes) across seagrass-sand edges in a Zostera muelleri patchy seagrass landscape. Carbon stocks were significantly higher (ca. 20%) inside seagrass patches than at seagrass-sand edges and bare sediments. Deposition was similar among all positions and most of the carbon was from allochthonous sources. Patch level attributes (e.g. edge distance) represent important determinants of the spatial heterogeneity of carbon stocks within seagrass ecosystems. Our findings indicate that carbon stocks of seagrass areas have likely been overestimated by not considering the influence of meadow landscapes, and have important relevance for the design of seagrass carbon stock assessments.

Whistle variability in South Atlantic spinner dolphins from the Fernando de Noronha Archipelago off Brazil

A series of quali- and quantitative analyses were conducted to evaluate the variability of spinner dolphin whistles from the Fernando de Noronha Archipelago off Brazil. Nine variables were extracted from each whistle contour, and the whistle contours shapes were classified into the seven categories described in Driscoll (1995). The analysis showed mean beginning and ending frequencies values of 10.78 and 12.74 kHz, respectively. on average, whistle duration was relatively short, with mean values around 0.495 s (N=702). Comparative analyses were also conducted to investigate the relationship between the obtained results and those presented in previous studies. When comparing averages, the results of the study of Oswald et al. (2003) in the Tropical Eastern Pacific (TEP) presented less significant differences in relation to this study; only whistle duration differed significantly between both works. The results of multivariate classification tests also pointed TEP population as the closest related to the population studied here. The similarities between such disjunct populations might be attributed to a more recent isolation event (the closing of the Panama Isthmus) than the divergence that has driven North and South Atlantic populations apart. (c) 2006 Acoustical Society of America.

Environmental and grazing influence on spatial variability of intertidal biofilm on subtropical rocky shores

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)