Investigating the effects of mopane worms (Imbrasia belina) on nutrients, Venetia-Limpopo Nature Reserve, South Africa

Ecologists have long been aware that large mammalian herbivores can alter ecosystem functioning in various ways, for example through changing where they defecate and urinate, which consequently affects nutrient cycling. The effects of herbivorous insects on ecosystems, however, have received limited attention until recently. Insects are capable of mass outbreaks, they can consume large volumes of vegetative material and can deposit large quantities of dung (frass), one example being the mopane worm, Imbrasia belina. This study looked at the effect of mopane worm frass on soil fertility in the mopane veld of the Venetia-Limpopo Nature Reserve and neighbouring Haakdoring farm. It found that mopane worms are capable of altering soil nutrient dynamics beneath the trees where they are browsing in three ways. Firstly, they increase the potential amount of nutrients deposited when compared with that deposited through conventional leaf litter. Secondly, they alter the rate of nutrient recycling by depositing nutrients in frass which decomposes more rapidly than conventional leaf litter. Lastly, they increase the amounts of potassium and phosphorus in the soil. While there is no conclusive data from this study that the mopane veld would become extinct if mopane worms were harvested to extinction, it has shown that there is relatively little evidence on how herbivorous insects could affect ecosystem functioning in the landscapes in which they occur. Further research is recommended that investigates how mopane worms influence soil fertility in more detail and over multiple geographical locations

Identifying and mitigating residual vibrations in wave-based control of lumped, flexible systems

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Wave-based control (WBC) is a technique for motion control of under-actuated flexible sys-tems. It envisages actuator motion as launching a motion wave into the system, while simulta-neously absorbing any wave returning from the system. For rest-to-rest motion the net launch displacement is set at half the target displacement. In absorbing the returning wave and vibra-tions, WBC moves the system the remaining distance to the target, with zero steady-state error. The focus of this paper is on very small residual vibrations around the target position which can endure for a long time after arrival at target. This issue was discovered through a recent devel-opment within WBC context on controlling complex two-dimensional, mass-spring, beam-like arrays. To date their existence has been unidentified. This paper investigates and interprets the nature of these vibrations, explains and identifies them based on wave ideas, and finally offers a new wave-based approach to mitigate or suppress them. It also discusses their implication, not just for WBC but for the general problem of control of flexible systems

Growth and habitat requirements of juvenile flatfish at nursery grounds in Galway Bay, Ireland

Coastal zones are essential nursery habitats for most juvenile flatfish species. Fish stocks are highly dependent on suitable coastal habitat features for obtaining food, shelter, and rapid growth during the vulnerable juvenile life stage. Understanding the ecological habitat requirements for juvenile flatfish is important in determining their abundance and to reliably predict potential impacts of changing coastal ecosystems on fish stocks. The present study assesses the influence of habitat characteristics on the growth and abundance of juvenile dab and plaice in four nursery areas within Galway Bay, Ireland. Field sampling was carried out in summer 2008 using a beam trawl for the collection of flatfish and a van Veen grab for the collection of sediment. The distribution and abundance of the juvenile flatfish was assessed in relation to biotic (predator–prey abundance) and abiotic (sediment size, organic content, depth, temperature, and salinity) habitat features. The condition and growth of flatfish were compared in different nursery areas and a model of habitat requirements for juvenile plaice and dab was developed. Significant variability of the measured characteristics was observed between nursery areas and high-quality nursery areas for dab and plaice were identified. These results will act as the basis for mapping of essential flatfish habitats in Galway Bay

Optimizing a Certified Proof Checker for a Large-Scale Computer-Generated Proof

In recent work, we formalized the theory of optimal-size sorting networks with the goal of extracting a verified checker for the large-scale computer-generated proof that 25 comparisons are optimal when sorting 9 inputs, which required more than a decade of CPU time and produced 27 GB of proof witnesses. The checker uses an untrusted oracle based on these witnesses and is able to verify the smaller case of 8 inputs within a couple of days, but it did not scale to the full proof for 9 inputs. In this paper, we describe several non-trivial optimizations of the algorithm in the checker, obtained by appropriately changing the formalization and capitalizing on the symbiosis with an adequate implementation of the oracle. We provide experimental evidence of orders of magnitude improvements to both runtime and memory footprint for 8 inputs, and actually manage to check the full proof for 9 inputs.Comment: IMADA-preprint-c

Full gait cycle analysis of lower limb and trunk kinematics and muscle activations during walking in participants with and without ankle instability

This document is the Accepted Manuscript version of the following article: Lynsey Northeast, Charlotte N. Gautrey, Lindsay Bottoms, Gerwyn Hughes, Andrew C. S. Mitchell, and Andrew Greenhalgh, ‘Full gait cycle analysis of lower limb and trunk kinematics and muscle activations during walking in participants with and without ankle instability’, Gait & Posture, Vol. 64: 114-118, July 2018. Under embargo until 7 June 2019. The final, definitive version is available online at doi: https://doi.org/10.1016/j.gaitpost.2018.06.001Background Chronic ankle instability (CAI) has previously been linked to altered lower limb kinematics and muscle activation characteristics during walking, though little research has been performed analysing the full time-series across the stance and swing phases of gait. Research Question The aim of this study was to compare trunk and lower limb kinematics and muscle activity between those with chronic ankle instability and healthy controls. Methods Kinematics and muscle activity were measured in 18 (14 males, 4 females) healthy controls (age 22.4 ± 3.6 years, height 177.8 ± 7.6 cm, mass 70.4 ± 11.9 kg, UK shoe size 8.4 ± 1.6), and 18 (13 males, 5 females) participants with chronic ankle instability (age 22.0 ± 2.7 years, height 176.8 ± 7.9 cm, mass 74.1 ± 9.6 kg, UK shoe size 8.1 ± 1.9) during barefoot walking trials, using a combined Helen Hayes and Oxford foot model. Surface electromyography (sEMG) was recorded for the tibialis anterior and gluteus medius. Full curve statistical parametric mapping was performed using independent and paired-samples T-tests. Results No significant differences were observed in kinematic or sEMG variables between or within groups for the duration of the swing phase of gait. A significantly increased forefoot-tibia inversion was seen in the CAI affected limb when compared to the CAI unaffected limb at 4–16% stance (p = 0.039). No other significant differences were observed. Significance There appears to be no differences in muscle activation and movement between CAI and healthy control groups. However, participants with CAI exhibited increased inversion patterns during the stance phase of gait in their affected limb compared to their unaffected limb. This may predispose those with CAI to episodes of giving way and further ankle sprains.Peer reviewedFinal Accepted Versio

Integrated plasmonic circuitry on a vertical-cavity surface-emitting semiconductor laser platform

Integrated plasmonic sources and detectors are imperative in the practical development of plasmonic circuitry for bio- and chemical sensing, nanoscale optical information processing, as well as transducers for high-density optical data storage. Here we show that vertical-cavity surface-emitting lasers (VCSELs) can be employed as an on-chip, electrically pumped source or detector of plasmonic signals, when operated in forward or reverse bias, respectively. To this end, we experimentally demonstrate surface plasmon polariton excitation, waveguiding, frequency conversion and detection on a VCSEL-based plasmonic platform. The coupling efficiency of the VCSEL emission to waveguided surface plasmon polariton modes has been optimized using asymmetric plasmonic nanostructures. The plasmonic VCSEL platform validated here is a viable solution for practical realizations of plasmonic functionalities for various applications, such as those requiring sub-wavelength field confinement, refractive index sensitivity or optical near-field transduction with electrically driven sources, thus enabling the realization of on-chip optical communication and lab-on-a-chip devices

Family functioning in humanitarian contexts:Correlates of the feminist-grounded family functioning scale among men and women in the eastern Democratic Republic of Congo

In humanitarian contexts, family functioning may have a positive influence on outcomes of mental health and wellbeing for both children and adults. This study sought to adapt and explore an existing family functioning measure for use in eastern Democratic Republic of Congo. Cross-sectional data were collected from 394 respondents (196 men and 198 women) in North Kivu, DRC. The Feminist-Grounded Family Functioning Scale was developed through qualitative research and cognitive testing which conceptualized a healthy and functioning family as one without gender and power hierarchies. Generalized linear mixed models stratified by gender assessed the association between family functioning and demographics, conflict experiences, and correlates of interest including gender attitudes, acceptance of harsh discipline, positive parenting, and power sharing. In the final adjusted models, family functioning among women was associated with positive parenting (β = 0.32, p = 0.009) and power sharing (β = 0.24, p < 0.001), but attitudes around gender and harsh discipline did not retain their significant association. Similarly, men’s family functioning was significantly associated with positive parenting (β = 0.41, p = 0.011) and power sharing (β = 0.16, p = 0.014). Results suggest that family functioning is positively associated with behaviors indicative of non-violent and equitable relationships between family members, but that behaviors might be attenuating the influence of attitudes on family functioning, as the significant association between attitudes and family functioning in the univariate models was not retained in the full models accounting for both behaviors and attitudes. Further research is needed to capture the context-specific nuances of family functioning and to understand the influence of gender and power hierarchies for families in conflict settings

Genome-Wide Association Study for Abscission Failure of Fruit Pericarps (Stick-Tights) in Wild Macadamia Germplasm

Macadamia pericarps that fail to abscise (‘stick-tights’) are an important trait to select against in breeding as they can harbour pests and diseases. Traditional macadamia breeding cycles are lengthy and expensive due to long juvenilities and large tree sizes. Thus, genome-wide association studies (GWAS) are an important investigative tool to identify candidate trait-linked markers to enable potential reductions in evaluation and selection cycles via marker-assisted selection (MAS) in young seedlings. This study assessed 199 wild macadamia germplasm accessions for stick-tight prevalence across two years. As the number of stick-tights per tree is limited by the number of nuts per tree, we conducted association analyses to identify SNPs linked with the number of stick-tights per tree, and examined whether such SNPs were also associated with, and thus confounded with, the number of nuts per tree. We also assessed associations with the proportion of stick-tights per total number of nuts. Thirty-two SNPs were associated with at least one of the stick-tight traits in one year (p < 0.001). Of all such SNPs, only one was associated with the number of nuts per tree (p < 0.001), indicating that most associations were not confounded with yield