The ionomics of three-spined stickleback on North Uist: elemental investigation of an ecological chemical mosaic

How does the abiotic chemistry of the environment affect biotic evolution? Organisms require approximately 25 elements to construct themselves, and the occurrence of these varies spatiotemporally in the environment, yet we know little about the elemental composition of animals beyond that of the commonest elements (C, N, P, K). Ionomics is the emerging study of the elemental sum of an organism’s ion makeup (i.e. the ionome), which focuses on the potential importance, relevance, and accessibility of all important compositional elements. These have become increasingly accessible through Inductively Coupled Plasma Mass Spectroscopy. The chemical and pH variation across the island of North Uist in the Scottish Western Isles, combined with the three-spined stickleback populations that inhabit the various lochs provides a unique study system with which to better understand chemical consequences for evolution and inform on how rapid changes to water chemistry and pH could affect fish populations. Multi-element analysis of fish and environmental components was combined with a common garden experiment, reciprocal water rearing and a developmental approach of staining for bone ossification, to investigate population ionomic variation, genotype vs. phenotype, adaptation and the consequences of water chemistry. Results showed that fish ionomics were population specific and directly affected by both water chemistry and nutritional availability. Invertebrate populations of prey items did not exhibit the same trends in site specific ionomics, though taxa specific differences were found and fish stomach contents indicated potential selective feeding behaviours. Ionomics exhibits plasticity under common chemical conditions, but has a genetic component and fish are still readily identifiable to their population of origin on an elemental level. Water rearing chemistry directly impacted hatching rates and hatching mortality as well as fish ionomics, growth and development. These results demonstrate not only the application of ionomics and multi-element analysis to questions of ecology, evolution and development, but also how such approaches can be integrated with more well established techniques and extremely suitable study systems to gain a better understanding of how biotic and abiotic components of environments interact to influence fish development, adaptation and evolution

The use of clamping grips and friction pads by tree frogs for climbing curved surfaces

Most studies on the adhesive mechanisms of climbing animals have addressed attachment against flat surfaces, yet many animals can climb highly curved surfaces, like twigs and small branches. Here we investigated whether tree frogs use a clamping grip by recording the ground reaction forces on a cylindrical object with either a smooth or anti-adhesive, rough surface. Furthermore, we measured the contact area of fore and hindlimbs against differently sized transparent cylinders and the forces of individual pads and subarticular tubercles in restrained animals. Our study revealed that frogs use friction and normal forces of roughly a similar magnitude for holding on to cylindrical objects. When challenged with climbing a non-adhesive surface, the compressive forces between opposite legs nearly doubled, indicating a stronger clamping grip. In contrast to climbing flat surfaces, frogs increased the contact area on all limbs by engaging not just adhesive pads but also subarticular tubercles on curved surfaces. Our force measurements showed that tubercles can withstand larger shear stresses than pads. SEM images of tubercles revealed a similar structure to that of toe pads including the presence of nanopillars, though channels surrounding epithelial cells were less pronounced. The tubercles' smaller size, proximal location on the toes and shallow cells make them probably less prone to buckling and thus ideal for gripping curved surfaces

The ionomics of three-spined stickleback on North Uist: elemental investigation of an ecological chemical mosaic

How does the abiotic chemistry of the environment affect biotic evolution? Organisms require approximately 25 elements to construct themselves, and the occurrence of these varies spatiotemporally in the environment, yet we know little about the elemental composition of animals beyond that of the commonest elements (C, N, P, K). Ionomics is the emerging study of the elemental sum of an organism’s ion makeup (i.e. the ionome), which focuses on the potential importance, relevance, and accessibility of all important compositional elements. These have become increasingly accessible through Inductively Coupled Plasma Mass Spectroscopy. The chemical and pH variation across the island of North Uist in the Scottish Western Isles, combined with the three-spined stickleback populations that inhabit the various lochs provides a unique study system with which to better understand chemical consequences for evolution and inform on how rapid changes to water chemistry and pH could affect fish populations. Multi-element analysis of fish and environmental components was combined with a common garden experiment, reciprocal water rearing and a developmental approach of staining for bone ossification, to investigate population ionomic variation, genotype vs. phenotype, adaptation and the consequences of water chemistry. Results showed that fish ionomics were population specific and directly affected by both water chemistry and nutritional availability. Invertebrate populations of prey items did not exhibit the same trends in site specific ionomics, though taxa specific differences were found and fish stomach contents indicated potential selective feeding behaviours. Ionomics exhibits plasticity under common chemical conditions, but has a genetic component and fish are still readily identifiable to their population of origin on an elemental level. Water rearing chemistry directly impacted hatching rates and hatching mortality as well as fish ionomics, growth and development. These results demonstrate not only the application of ionomics and multi-element analysis to questions of ecology, evolution and development, but also how such approaches can be integrated with more well established techniques and extremely suitable study systems to gain a better understanding of how biotic and abiotic components of environments interact to influence fish development, adaptation and evolution

Dijet Mass Spectrum Limits on Flavor-Universal Colorons

Using recent D0 data on the dijet mass spectrum, we present a limit on flavor-universal colorons. At 95% CL we find Mc/cot(theta) > 837 GeV. We discuss the implications of this limit for models of quark compositeness, non-standard gluon interactions, and dynamical electroweak symmetry breaking. In addition, we place a lower bound Lambda_A8 > 2.1 TeV on the scale of color-octet axial-vector contact interactions among quarks which could arise in models of quark compositeness.Comment: 8 pages, 3 figure

Reconciling Storegga tsunami sedimentation patterns with modelled wave heights : a discussion from the Shetland Isles field laboratory.

The Shetland Isles represent an ideal field laboratory for tsunami geoscience research. This is due to the widespread preservation of Holocene tsunami sediments in coastal peat deposits. This study uses published accounts of the Holocene Storegga Slide tsunami to illustrate how two different approaches – mapping of tsunami sediments and numerical modelling – produce radically different run‐up heights. The Storegga Slide is one of the world largest submarine slides and took place ca 8150 cal yr bp on the continental slope west of Norway. The tsunami generated by the landslide deposited locally extensive sheets of marine sand and gravel, as well as redeposited clasts of peat across the contemporary land surface. These sediment accumulations have subsequently been buried by peat growth during the Holocene while exposures of the deposits are locally visible in coastal cliff sections. In several areas, the tsunami sediments can be traced upslope and inland within the peat as tapering sediment wedges up to maximum altitudes of between ca 8·1 m and 11·8 m above present sea level. Since reconstructions of palaeo‐sea level for Shetland for ca 8150 cal yr bp suggest an altitude of 20 m below high tide on the day that the tsunami struck, it has been inferred that the minimum tsunami run‐up was locally between 28·1 m (8·1 + 20 m) and 31·8 m (11·8 + 20 m). However, numerical models of the tsunami for Shetland suggest that the wave height may only have reached a highest altitude in the order of +13 m above sea level on the day the tsunami took place. In this paper a description is given of the sedimentary evidence for tsunami run‐up in the Shetland Isles. This is followed by an evaluation of where the palaeo‐sea level was located when the tsunami occurred. Significant differences are highlighted in tsunami inundation estimates between those based on the observed (geological) data and the theoretically‐modelled calculations. This example from the Shetland Isles may have global significance since it exemplifies how two different approaches to the reconstruction of tsunami inundation at the coast can produce radically different results with modelled wave height at the coast being considerably less than the geological estimates of tsunami run‐up

The biomechanics of tree frogs climbing curved surfaces: a gripping problem

The adhesive mechanisms of climbing animals have become an important research topic because of their biomimetic implications. We examined the climbing abilities of hylid tree frogs on vertical cylinders of differing diameter and surface roughness to investigate the relative roles of adduction forces (gripping) and adhesion. Tree frogs adhere using their toe pads and subarticular tubercles, the adhesive joint being fluid-filled. Our hypothesis was that, on an effectively flat surface (adduction forces on the largest 120 mm diameter cylinder were insufficient to allow climbing), adhesion would effectively be the only means by which tree frogs could climb, but on the two smaller diameter cylinders (44 mm and 13 mm), frogs could additionally utilise adduction forces by gripping the cylinder either with their limbs outstretched or by grasping around the cylinder with their digits, respectively. The frogs' performance would also depend on whether the surfaces were smooth (easy to adhere to) or rough (relatively non-adhesive). Our findings showed that climbing performance was highest on the narrowest smooth cylinder. Frogs climbed faster, frequently using a 'walking trot' gait rather than the 'lateral sequence walk' used on other cylinders. Using an optical technique to visualize substrate contact during climbing on smooth surfaces, we also observed an increasing engagement of the subarticular tubercles on the narrower cylinders. Finally, on the rough substrate, frogs were unable to climb the largest diameter cylinder, but were able to climb the narrowest one slowly. These results support our hypotheses and have relevance for the design of climbing robots

It's not the 'what', but the 'how':Exploring the role of debt in natural resource (un)sustainability

<div><p>A debt-based economy cannot survive without economic growth. However, if private debt consistently grows faster than GDP, the consequences are financial crises and the current unprecedented level of global debt. This policy dilemma is aggravated by the lack of analyses factoring the impact of debt-growth cycles on the environment. What is really the relationship between debt and natural resource sustainability, and what is the role of debt in decoupling economic growth from natural resource availability? Here we present a conceptual Agent-Based Model (ABM) that integrates an environmental system into an ABM representation of Steve Keen’s debt-based economic models. Our model explores the extent to which debt-driven processes, within debt-based economies, enhance the decoupling between economic growth and the availability of natural resources. Interestingly, environmental and economic collapse in our model are not caused by debt growth, or the debt-based nature of the economic system itself (i.e. the ‘<i>what</i>’), but rather, these are due to the inappropriate use of debt by private actors (i.e. the ‘<i>how</i>’). Firms inappropriately use bank credits for speculative goals–rather than production-oriented ones–and for exponentially increasing rates of technological development. This context creates temporal mismatches between natural resource growth and firms’ resource extraction rates, as well as between economic growth and the capacity of the government to effectively implement natural resource conservation policies. This paper discusses the extent to which economic growth and the availability of natural resources can be re-coupled through a more sustainable use of debt, for instance by shifting mainstream banking forces to partially support environmental conservation as well as economic growth.</p></div

The methodology of on the spot accident investigations in the UK

A new ’On-The-Spot’ (OTS) accident research project is now underway in the UK. This project enables expert investigators to attend the scene of an accident within 15 minutes of the incident occurring, which allows the collection of accident data that would otherwise be quickly lost. This paper considers previous studies and the justification for a new research approach before describing methodology used on the spot and during subsequent follow-up research. Investigations focus on all types of vehicles (including damage, failures, features fitted and their contribution); the highway (including design, features, maintenance and condition); the human factors (including drivers, riders, passengers and pedestrians); and the injuries sustained. Five hundred crashes will be studied in depth each year. The project objectives include establishing an in-depth database that will permit analyses to better understand the causes of crashes and injuries, and assist in the development of solutions

Prioritisation of potential agents for the biological control of the invasive alien weed, Pereskia aculeata (Cactaceae), in South Africa

Pereskia aculeata Miller (Cactaceae) is an invasive alien species in South Africa that is native in Central and South America. In South Africa, P. aculeata outcompetes native plant species leading to a reduction in biodiversity at infested sites. Herbicidal and mechanical control of the plant is ineffective and unsustainable, so biological control is considered the only potential solution. Climatic matching and genotype matching indicated that the most appropriate regions in which to collect biological control agents were Santa Catarina and Rio de Janeiro provinces in Southern Brazil. Surveys throughout the native distribution resulted in 15 natural enemy species that were associated with the plant. Field host range data, as well as previous host plant records, were used to prioritise which of the species were most likely to be suitably host specific for release in South Africa. The mode of damage was used to determine which species were most likely to be damaging and effective if released. The most promising species prioritised for further study, including host specificity and impact studies, were the stem-wilter Catorhintha schaffneri Brailovsky and Garcia (Coreidae); the stem boring species Acanthodoxus machacalis Martins and Monné (Cerambycidae), Cryptorhynchus sp. (Curculionidae) and Maracayia chlorisalis (Walker) (Crambidae) and the fruit galler Asphondylia sp. (Cecidomyiidae). By prioritising the potential biological control agents that are most likely to be host-specific and damaging, the risk of conducting host specificity testing on unsuitable or ineffective biological control agents is reduced

Cohesin is required for long-range enhancer action at the Shh locus

The regulatory landscapes of developmental genes in mammals can be complex, with enhancers spread over many hundreds of kilobases. It has been suggested that three-dimensional genome organisation, particularly topologically associating domains formed by cohesin-mediated loop extrusion, are important for enhancers to act over such large genomic distances. By coupling acute protein degradation with synthetic activation by targeted transcription factor recruitment, here we show that cohesin, but not CTCF, is required for activation of a target gene – Shh - by distant enhancers in mouse embryonic stem cells. Cohesin is not required for activation directly at the promoter or from an enhancer located closer to the Shh gene. Our findings support the hypothesis that chromatin compaction mediated by cohesin-mediated loop extrusion allows for genes to be activated by enhancers that are located many hundreds of kilobases away in the linear genome but suggests that cohesin is dispensable for more genomically close enhancers