Differences in the escape response of a grapsid crab in the field and in the laboratory

Escape behaviours of prey animals are frequently used to study the neural control of behaviour. Escape responses are robust, fast, and can be reliably evoked under both field and laboratory conditions. Many escape responses are not as simple as previously suggested, however, and are often modulated by a range of contextual factors. To date it has been unclear to what extent behaviours studied in controlled laboratory experiments are actually representative of the behaviours that occur under more natural conditions. Here we have used the model species, Neohelice granulata, a grapsid crab, to show that there are significant differences between the crabs' escape responses in the field compared to those previously documented in laboratory experiments. These differences are consistent with contextual adjustments such as the availability of a refuge and have clear consequences for understanding the crabs' neural control of behaviour. Furthermore, the methodology used in this study mirrors the methodology previously used in fiddler crab research, allowing us to show that the previously documented differences in escape responses between these grapsid species are real and substantial. Neohelice's responses are delayed and more controlled. Overall, the results highlight the adaptability and flexibility of escape behaviours and provide further evidence that the neural control of behaviour needs to be address in both the laboratory and field context.Fil: Hemmi, J. M.. University of Western Australia; AustraliaFil: Tomsic, Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; Argentin

Psi-series solutions of the cubic H\'{e}non-Heiles system and their convergence

The cubic H\'enon-Heiles system contains parameters, for most values of which, the system is not integrable. In such parameter regimes, the general solution is expressible in formal expansions about arbitrary movable branch points, the so-called psi-series expansions. In this paper, the convergence of known, as well as new, psi-series solutions on real time intervals is proved, thereby establishing that the formal solutions are actual solutions

Communities in university mathematics

This paper concerns communities of learners and teachers that are formed, develop and interact in university mathematics environments through the theoretical lens of Communities of Practice. From this perspective, learning is described as a process of participation and reification in a community in which individuals belong and form their identity through engagement, imagination and alignment. In addition, when inquiry is considered as a fundamental mode of participation, through critical alignment, the community becomes a Community of Inquiry. We discuss these theoretical underpinnings with examples of their application in research in university mathematics education and, in more detail, in two Research Cases which focus on mathematics students' and teachers' perspectives on proof and on engineering students' conceptual understanding of mathematics. The paper concludes with a critical reflection on the theorising of the role of communities in university level teaching and learning and a consideration of ways forward for future research

3D co-cultures of osteoblasts and endothelial cells in DegraPol foam: Histological and high field MRI analyses of pre-engineered capillary networks in bone grafts

Tissue engineering of bone grafts was addressed in a critical size model on the chick chorioallantoic membrane model (CAM assay), using DegraPol(R) (DP) foam as scaffold material. The scaffolds were seeded with cultures of human osteoblasts (OB) and human en notdo notthelial cells (EC), respectively, or with a co-culture of the two cell types (control: no cells). In vitro samples (7 days cultivation) and ex vivo CAM samples at incubation day 15 (ID 15) were analyzed by high field magnetic resonance imaging (MRI) and histology. The co-culture system performed best with respect to perfusion, as assessed by contrast-enhanced MRI using Gd-DTPA. The scaffold seeded by the co-culture supported an increased vascular ingrowth, which was confirmed by histological analysis. DP foam is a suitable scaffold for bone tissue engineering and the MRI technique allows for non-destructive and quantitative assessment of perfusion capability during early stages of bone forming constructs

Submerged carbonate banks aggregate pelagic megafauna in offshore tropical Australia

This research was undertaken for the Marine Biodiversity Hub, a collaborative partnership supported through funding from the Australian Government’s National Environmental Research Program (NERP). PB was the recipient of a scholarship for international fees during the course of this work. SN publishes with permission of the Chief Executive Officer, Geoscience Australia.The conservation of marine biodiversity is firmly embedded in national and international policy frameworks. However, the difficulties associated with conducting broad-scale surveys of oceanic environments restrict the evidence base available for applied management in pelagic waters. For example, the Oceanic Shoals Australian Marine Park (AMP) was established in 2012 in a part of Australia’s continental shelf where unique topographic features are thought to support significant levels of biodiversity, yet where our understanding of ecological processes remains limited. We deployed mid-water baited remote underwater video systems (mid-water BRUVS) in the Oceanic Shoals AMP to provide the first non-extractive baseline assessment of pelagic wildlife communities in the area. We used these observations and high-resolution multibeam swaths of the seafloor to explore potential relationships between prominent geomorphological features and the (i) composition, (ii) richness, and (iii) relative abundance of pelagic communities. We documented 32 vertebrate species across three sampling areas, ranging from small baitfish to large sharks and rays, and estimated that up to nearly twice as many taxa may occur within the region as a whole. This highlights the Oceanic Shoals AMP as a reservoir of biodiversity comparable to other documented offshore oceanic hotspots. Our results also confirm the AMP as a possible distant foraging destination for IUCN red listed sea turtles, and a potential breeding and/or nursing ground for a number of charismatic cetaceans. Model outputs indicate that both species richness and abundance increase in proximity to raised geomorphic structures such as submerged banks and pinnacles, highlighting the influence of submarine topography on megafauna distribution. By providing a foundational understanding of spatial patterns in pelagic wildlife communities throughout a little studied region, our work demonstrates how a combination of non-destructive sampling techniques and predictive models can provide new opportunities to support decision-making under data shortage.Publisher PDFPeer reviewe

Measurement of tau polarization in e+ e- annihilation at sqrt{s}=58 GeV

The polarization of tau leptons in the reaction e+ e- --> tau+ tau- has been measured using a e+e- collider, TRISTAN, at the center-of-mass energy of 58 GeV. From the kinematical distributions of daughter particles in tau --> e nu nu-bar, mu nu nu-bar, rho nu or pi(K) nu decays, the average polarization of tau- and its forward-backward asymmetry have been evaluated to be 0.012 +- 0.058 and 0.029 +- 0.057, respectively.Comment: 18 pages, 5 figure

Seminal fluid compromises visual perception in honeybee queens reducing their survival during additional mating flights

Queens of social insects make all mate-choice decisions on a single day, except in honeybees whose queens can conduct mating flights for several days even when already inseminated by a number of drones. Honeybees therefore appear to have a unique, evolutionarily derived form of sexual conflict: a queen's decision to pursue risky additional mating flights is driven by later-life fitness gains from genetically more diverse worker-offspring but reduces paternity shares of the drones she already mated with. We used artificial insemination, RNA-sequencing and electroretinography to show that seminal fluid induces a decline in queen vision by perturbing the phototransduction pathway within 24-48 hr. Follow up field trials revealed that queens receiving seminal fluid flew two days earlier than sister queens inseminated with saline, and failed more often to return. These findings are consistent with seminal fluid components manipulating queen eyesight to reduce queen promiscuity across mating flights

Colouration and Colour Changes of the Fiddler Crab, Uca capricornis: A Descriptive Study

Colour changes in animals may be triggered by a variety of social and environmental factors and may occur over a matter of seconds or months. Crustaceans, like fiddler crabs (genus Uca), are particularly adept at changing their colour and have been the focus of numerous studies. However, few of these studies have attempted to quantitatively describe the individual variation in colour and pattern or their adaptive significance. This paper quantitatively describes the colour patterns of the fiddler crab Uca capricornis and their ability to change on a socially significant timescale. The most dramatic changes in colour pattern are associated with moulting. These ontogenetic changes result in a general reduction of the colour pattern with increasing size, although females are more colourful and variable than similarly-sized males. Uca capricornis are also capable of rapid colour changes in response to stress, but show no endogenous rhythms associated with the semilunar and tidal cycles commonly reported in other fiddler crabs. The extreme colour polymorphism and the relative stability of the colour patterns in Uca capricornis are consistent with their use in visually mediated mate recognition