Bayesian Optimisation for Safe Navigation under Localisation Uncertainty

In outdoor environments, mobile robots are required to navigate through terrain with varying characteristics, some of which might significantly affect the integrity of the platform. Ideally, the robot should be able to identify areas that are safe for navigation based on its own percepts about the environment while avoiding damage to itself. Bayesian optimisation (BO) has been successfully applied to the task of learning a model of terrain traversability while guiding the robot through more traversable areas. An issue, however, is that localisation uncertainty can end up guiding the robot to unsafe areas and distort the model being learnt. In this paper, we address this problem and present a novel method that allows BO to consider localisation uncertainty by applying a Gaussian process model for uncertain inputs as a prior. We evaluate the proposed method in simulation and in experiments with a real robot navigating over rough terrain and compare it against standard BO methods.Comment: To appear in the proceedings of the 18th International Symposium on Robotics Research (ISRR 2017

Mouse podoplanin supports adhesion and aggregation of platelets under arterial shear: a novel mechanism of haemostasis

The Podoplanin-CLEC-2 axis is critical in mice for prevention of haemorrhage in the cerebral vasculature during mid-gestation. This raises the question as to how platelets are captured by podoplanin on neuroepithelial cells in a high shear environment. In this study, we demonstrate that mouse platelets form stable aggregates on mouse podoplanin at arterial shear through a CLEC-2 and Src kinase-dependent pathway. Adhesion and aggregation are also dependent on the platelet glycoprotein (GP) receptors, integrin αIIbβ3 and GPIb, and the feedback agonists ADP and thromboxane A2 (TxA2). CLEC-2 does not bind to von Willebrand factor (VWF) suggesting that the interaction with podoplanin is sufficient to both tether and activate platelets. Consistent with this, surface plasmon resonance measurements reveal that mouse CLEC-2 binds to mouse podoplanin with nanomolar affinity. The present findings demonstrate a novel pathway of haemostasis in which podoplanin supporting platelet capture and activation at arteriolar rates of shear

3,4-Methylenedioxymethamphetamine (MDMA) neurotoxicity in rats: a reappraisal of past and present findings

RATIONALE: 3,4-Methylenedioxymethamphetamine (MDMA) is a widely abused illicit drug. In animals, high-dose administration of MDMA produces deficits in serotonin (5-HT) neurons (e.g., depletion of forebrain 5-HT) that have been interpreted as neurotoxicity. Whether such 5-HT deficits reflect neuronal damage is a matter of ongoing debate. OBJECTIVE: The present paper reviews four specific issues related to the hypothesis of MDMA neurotoxicity in rats: (1) the effects of MDMA on monoamine neurons, (2) the use of “interspecies scaling” to adjust MDMA doses across species, (3) the effects of MDMA on established markers of neuronal damage, and (4) functional impairments associated with MDMA-induced 5-HT depletions. RESULTS: MDMA is a substrate for monoamine transporters, and stimulated release of 5-HT, NE, and DA mediates effects of the drug. MDMA produces neurochemical, endocrine, and behavioral actions in rats and humans at equivalent doses (e.g., 1–2 mg/kg), suggesting that there is no reason to adjust doses between these species. Typical doses of MDMA causing long-term 5-HT depletions in rats (e.g., 10–20 mg/kg) do not reliably increase markers of neurotoxic damage such as cell death, silver staining, or reactive gliosis. MDMA-induced 5-HT depletions are accompanied by a number of functional consequences including reductions in evoked 5-HT release and changes in hormone secretion. Perhaps more importantly, administration of MDMA to rats induces persistent anxiety-like behaviors in the absence of measurable 5-HT deficits. CONCLUSIONS: MDMA-induced 5-HT depletions are not necessarily synonymous with neurotoxic damage. However, doses of MDMA which do not cause long-term 5-HT depletions can have protracted effects on behavior, suggesting even moderate doses of the drug may pose risks

The Present and Future Role of Insect-Resistant Genetically Modified Maize in IPM

Commercial, genetically-modified (GM) maize was first planted in the United States (USA, 1996) and Canada (1997) but now is grown in 13 countries on a total of over 35 million hectares (\u3e24% of area worldwide). The first GM maize plants produced a Cry protein derived from the soil bacteriumBacillus thuringiensis (Bt), which made them resistant to European corn borer and other lepidopteran maize pests. New GM maize hybrids not only have resistance to lepidopteran pests but some have resistance to coleopteran pests and tolerance to specific herbicides. Growers are attracted to the Btmaize hybrids for their convenience and because of yield protection, reduced need for chemical insecticides, and improved grain quality. Yet, most growers worldwide still rely on traditional integrated pest management (IPM) methods to control maize pests. They must weigh the appeal of buying insect protection “in the bag” against questions regarding economics, environmental safety, and insect resistance management (IRM). Traditional management of maize insects and the opportunities and challenges presented by GM maize are considered as they relate to current and future insect-resistant products. Four countries, two that currently have commercialize Bt maize (USA and Spain) and two that do not (China and Kenya), are highlighted. As with other insect management tactics (e.g., insecticide use or tillage), GM maize should not be considered inherently compatible or incompatible with IPM. Rather, the effect of GM insect-resistance on maize IPM likely depends on how the technology is developed and used

Forest biodiversity, ecosystem functioning and the provision of ecosystem services

Forests are critical habitats for biodiversity and they are also essential for the provision of a wide range of ecosystem services that are important to human well-being. There is increasing evidence that biodiversity contributes to forest ecosystem functioning and the provision of ecosystem services. Here we provide a review of forest ecosystem services including biomass production, habitat provisioning services, pollination, seed dispersal, resistance to wind storms, fire regulation and mitigation, pest regulation of native and invading insects, carbon sequestration, and cultural ecosystem services, in relation to forest type, structure and diversity. We also consider relationships between forest biodiversity and multifunctionality, and trade-offs among ecosystem services. We compare the concepts of ecosystem processes, functions and services to clarify their definitions. Our review of published studies indicates a lack of empirical studies that establish quantitative and causal relationships between forest biodiversity and many important ecosystem services. The literature is highly skewed; studies on provisioning of nutrition and energy, and on cultural services, delivered by mixed-species forests are under-represented. Planted forests offer ample opportunity for optimising their composition and diversity because replanting after harvesting is a recurring process. Planting mixed-species forests should be given more consideration as they are likely to provide a wider range of ecosystem services within the forest and for adjacent land uses. This review also serves as the introduction to this special issue of Biodiversity and Conservation on various aspects of forest biodiversity and ecosystem services

Effects of past and current crop management on soil microbial biomass and activity

As soil biota is influenced by a number of factors, including land use and management techniques, changing management practices could have significant effects on the soil microbial properties and processes. An experiment was conducted to investigate differences in soil microbiological properties caused by long- and short-term management practices. Intact monolith lysimeters (0.2 m2 surface area) were taken from two sites of the same soil type that had been under long-term organic or conventional crop management and were then subjected to the same 2½-year crop rotation (winter barley (Hordeum vulgare L.), maize (Zea mais L.), lupin (Lupinus angustifolius L.) rape (Brassica napus L. ssp. oleifera)) and two fertiliser regimes (following common organic and conventional practices). Soil samples were taken after crop harvest and analysed for microbial biomass C and N, microbial activity (fluorescein diacetate hydrolysis, arginine deaminase activity, dehydrogenase activity) and total C and N. The incorporation of the green manure stimulated growth and activity of the microbial communities in soils of both management histories. Soil microbial properties did not show any differences between organically and conventionally fertilised soils, indicating that crop rotation and plant type had a larger influence on the microbial biomass and enzyme activities than fertilisation. Initial differences in microbial biomass declined, while the effects of farm management history were still evident in enzyme activities and total C and N. Links between enzyme activities and microbial biomass C varied depending on treatment indicating differences in microbial community composition

The proximate composition of three marine pelagic fish: blue whiting (Micromesistius poutassou), boarfish (Capros aper) and Atlantic herring (Clupea harengus)

peer reviewedThis study presents data from an in-depth proximate compositional analysis of three marine fish species: blue whiting (Micromesistius poutassou), boarfish (Capros aper) and Atlantic herring (Clupea harengus). These fish contained significant amounts of protein (16–17%), lipids (4–11%) and minerals (2–6% ash). The proteins, particularly from boarfish, had close to optimum amino acid profiles for human and fish nutrition. They compared favourably with other fish species in terms of total lipids and relative concentration of the omega-3 fatty acids docosahexaenoic acid and eicosapentaenoic acid (11.8–13.3% and 5.9–8.1% in triacylglycerols [TG] and 24.6–35.4% and 5.8–12.0% in phospholipids [PL]). Atlantic herring had the highest lipid content among the three fish and was found to contain high levels of PL poly-unsaturated fatty acids, including omega-3 fatty acids. Minerals detected in the fish included calcium (272–1,520 mg/100 g), phosphorus (363–789 mg/100 g), iron (1.07–2.83 mg/100 g), magnesium (40.70–62.10 mg/100 g), potassium (112.00–267.00 mg/100 g), selenium (0.04–0.06 mg/100 g), sodium (218.00–282.00 mg/100 g) and zinc (1.29–5.57 mg/100 g). Boarfish had the highest ash fraction and also the highest levels of all the minerals, except potassium. Atlantic herring had considerably lower mineral content compared with the other two species and, levels detected were also lower than those reported in previously published studies. Heavy metals contents were quantified, and levels were significantly below the maximum allowable limits for all elements except arsenic, which ranged from 1.34 to 2.44 mg/kg in the three fish species. Data outlined here will be useful for guiding product development. Future studies would benefit from considering catch season, sex and developmental stage of the fish

Three new species of Sarcocornia (Chenopodiaceae) from South Africa

Intensive field studies and collection of specimens conducted from 2000 to 2006 were aimed at the description of vegetation of saline habitats of southern Africa (Mucina et al. 2006a – c). This also set the basis for a systematic and biogeographical study of South African Sarcocornia (Steffen 2006), which is a prominent floristic element of hygrohalophytic habitats worldwide. Our molecular phylogenetic studies based on ETS and chloroplast-genome sequences and our intensive morphological survey of the genus (Steffen et al. 2007, Steffen et al. in press) revealed that Sarcocornia A. J. Scott contains two species not recognised in older revisions by Moss (1954), Tölken (1967) and O’Callaghan (1992). Furthermore, a third species is proposed to be newly described here. The known collections pertinent to this taxon had been previously considered to represent Sarcocornia perennis (Mill.) A. J. Scott, a species well-known from Eurasia (e.g. Moss 1954; Tölken 1967; O’Callaghan 1992; Davy et al. 2006). Despite its morphological and ecological similarity to the Eurasian S. perennis, detailed morphological investigations revealed differences, mainly in seed morphology. A recent molecular-phylogenetic analysis of the Salicornioideae (Kadereit et al. 2006) showed that S. perennis is clearly diphyletic and that the southern African “S. perennis” (sensu auctorum austroafricanum) represents an independent evolutionary entity