Cosmology of a Friedmann-Lama\^itre-Robertson-Walker 3-brane, Late-Time Cosmic Acceleration, and the Cosmic Coincidence

A late epoch cosmic acceleration may be naturally entangled with cosmic coincidence -- the observation that at the onset of acceleration the vacuum energy density fraction nearly coincides with the matter density fraction. In this Letter we show that this is indeed the case with the cosmology of a Friedmann-Lama\^itre-Robertson-Walker (FLRW) 3-brane in a five-dimensional anti-de Sitter spacetime. We derive the four-dimensional effective action on a FLRW 3-brane, which helps define a general reduction formula, namely, $M_P^{2}=\rho_{b}/|\Lambda_5|$, where $M_{P}$ is the effective Planck mass, $\Lambda_5$ is the 5-dimensional cosmological constant, and $\rho_b$ is the sum of the 3-brane tension $V$ and the matter density $\rho$. The behavior of the background solution is consistent with the results based on the form of the 4D effective potential. Although the range of variation in $\rho_{b}$ is strongly constrained, the big bang nucleosynthesis bound on the time variation of the renormalized Newton constant $G_N = (8\pi M_P^2)^{-1}$ is satisfied when the ratio $V/\rho \gtrsim {O} (10^2)$ on cosmological scales. The same bound leads to an effective equation of state close to -1 at late epochs in accordance with current astrophysical and cosmological observations.Comment: 5 pages, 3 figures; v2: version to be published in PR

A Temperature-Dependent Development Model for Willow Beetle Species (Coleoptera: Chrysomelidae) in Ireland: Simulation of Phenology/Voltinism in Response to Climate Change

Rising fossil fuel prices, energy security and adherence to existing European Union (EU) climate/energy policies means that Ireland must look towards alternative energy sources to meet future demand. Woody biomass in the form of short rotation coppice willow (SRCW) is considered a viable option. SRCW is vulnerable to damage by a range of diseases and pests however. The blue (Phratora vulgatissima) and brown (Galerucella lineola) willow beetles (Coleoptera: Chrysomelidae) are identified economically as two of the most damaging insect pests of SRCW in Ireland. Policies which mandate levels of renewable energy use, to mitigate future climate change, fail to consider adaptation in the energy sector under increased levels of pestilence due to projected changes in the climate system. The effects of abiotic and biotic factors, mainly temperature and photoperiod, but also host plant, on beetle development were investigated. Constant temperature experiments showed that development time for all assessed life-cycle stages decreased as temperature increased. P. vulgatissima oviposition period and total fecundity were influenced by temperature also. Development was not found to vary considerably when P. vulgatissima larvae were reared on different host plant varieties (Tora, Resolution, Tordis and Inger) across a similar range of constant temperatures. A critical daylength (CDL) for P. vulgatissima facultative reproduction was calculated. The relationship between temperature and P. vulgatissima and G. lineola life-cycle stage development was represented by applying criteria satisfying non-linear deterministic and stochastic functions to development rates and development time distributions respectively. A combined phenology/voltinism model was constructed incorporating a Salix. viminalis degree-day budburst model, the temperature-dependent development rate and temperature-independent time distribution functions, and information regarding the reproductive diapause inducing CDL. Using observed temperature and statistically downscaled climate scenarios derived from different global climate models (GCMs) forced with different emission scenarios, model results suggested important spatio-temporal changes in the life cycle and voltinism of P. vulgatissima, including two annual generations for 5% and 50% beetle emergence proportions (E.P) at all observed locations nationally by the 2050s and three annual generations for 5% E.P for a percentage of years at certain inland and south-westerly observed locations by the 2080s. The findings from this research may have implications for regional SRCW production, integrated pest and crop management and climate and energy policy in the future

Schistosoma mansoni: functional expression and characterisation of cathepsin L1 and cathepsin L2

The cysteine proteinases, cathepsins LI (SmCLl) and L2 (SmCL2) from the parasitic helminth Schistosoma mansoni were functionally expressed in Saccharomyces cerevisiae. By transforming the yeast with cDNAs encoding the complete pre-pro-enzymes, the recombinant proteinases were secreted into the culture medium from which they were purified by gel filtration and/or anion exchange chromatography. The enzymes were secreted by the yeast cells in their mature, active form and demonstrated characteristics typical of cathepsin L-like cysteine proteinases. Proteins in the purified fractions were reactive with anti-sera prepared against the recombinant enzymes which had been expressed in, and purified from extracts of Escherichia coli. Yeast-expressed SmCLl and SmCL2 displayed distinct differences in their specificities for synthetic peptide substrates; SmCLl favours substrates containing aliphatic (P3)-aliphatic (P2)-positive or polar hydrophobic (Pi) residues, whereas SmCL2 showing a preference for aliphatic (P3)-aromatic (P2)-positive (Pi). SmCLl cleaved a broader range of substrates tested and was also active over a wider pH range than SmCL2. SmCLl showed a pH optimum of 6.5 for activity against Z-Phe-Arg-NHMec, while SmCL2 was optimally active at pH 5.5 against this substrate. RT-PCR and immunoblotting studies revealed expression profiles of these proteinases also differed in the various life cycle stages of S. mansoni; both proteinases are expressed in male and female adults but at different levels, and the pro-form of SmCLl is also expressed in cercariae. Immunolocalisation experiments demonstrated that SmCLl was expressed in the gastrodermal cells lining the schistosome gut, as well as in the tegument of adult worms. Immunoblotting studies which detected the presence of SmCLl in the excretory/secretory products of adult worms suggests that this enzyme is secreted by the parasite. Moreover, recombinant yeast-expressed SmCLl had a marked preference for haemoglobin as substrate. Collectively, these results suggest that SmCLl plays some role in the degradation of host haemoglobin in the schistosome gut. SmCL2 has been localised to the reproductive organs of adult schistosomes by another laboratory and has been implicated to be involved in egg formation in female parasites. Therefore, SmCLl and SmCL2 perform different functions in schistosomes. Both these enzymes now represent novel targets at which chemotherapy and/or immunoprophylaxis may be directed

A Temperature-Dependent Development Model for Willow Beetle Species (Coleoptera: Chrysomelidae) in Ireland: Simulation of Phenology/Voltinism in Response to Climate Change

Rising fossil fuel prices, energy security and adherence to existing European Union (EU) climate/energy policies means that Ireland must look towards alternative energy sources to meet future demand. Woody biomass in the form of short rotation coppice willow (SRCW) is considered a viable option. SRCW is vulnerable to damage by a range of diseases and pests however. The blue (Phratora vulgatissima) and brown (Galerucella lineola) willow beetles (Coleoptera: Chrysomelidae) are identified economically as two of the most damaging insect pests of SRCW in Ireland. Policies which mandate levels of renewable energy use, to mitigate future climate change, fail to consider adaptation in the energy sector under increased levels of pestilence due to projected changes in the climate system. The effects of abiotic and biotic factors, mainly temperature and photoperiod, but also host plant, on beetle development were investigated. Constant temperature experiments showed that development time for all assessed life-cycle stages decreased as temperature increased. P. vulgatissima oviposition period and total fecundity were influenced by temperature also. Development was not found to vary considerably when P. vulgatissima larvae were reared on different host plant varieties (Tora, Resolution, Tordis and Inger) across a similar range of constant temperatures. A critical daylength (CDL) for P. vulgatissima facultative reproduction was calculated. The relationship between temperature and P. vulgatissima and G. lineola life-cycle stage development was represented by applying criteria satisfying non-linear deterministic and stochastic functions to development rates and development time distributions respectively. A combined phenology/voltinism model was constructed incorporating a Salix. viminalis degree-day budburst model, the temperature-dependent development rate and temperature-independent time distribution functions, and information regarding the reproductive diapause inducing CDL. Using observed temperature and statistically downscaled climate scenarios derived from different global climate models (GCMs) forced with different emission scenarios, model results suggested important spatio-temporal changes in the life cycle and voltinism of P. vulgatissima, including two annual generations for 5% and 50% beetle emergence proportions (E.P) at all observed locations nationally by the 2050s and three annual generations for 5% E.P for a percentage of years at certain inland and south-westerly observed locations by the 2080s. The findings from this research may have implications for regional SRCW production, integrated pest and crop management and climate and energy policy in the future

Design of a brushless A.C. servo-motor using neodymium iron boron permanent magnet meterial

The excellent performance characteristics of Brushless Servo-motors have led to their widespread use in areas such as Robotics, CNC Machines and in the Aero-space Industry. The development of Neodymium Iron Boron permanent magnet material with the highest available Energy Product levels promised improved motor performance coupled with reduced magnet costs. However this material exhibits large changes in magnetic properties with temperature when compared with Samarium Cobalt magnets, the permanent magnet material commonly used in these applications. This research examines the feasibility of substituting Samarium Cobalt magnets with Neodymium magnets in a redesigned Servo-motor. Equations are developed which predict the motor performance based on design input data, machine physical dimensions and magnetic properties of the permanent magnet material. A winding analysis program is developed and is used to investigate the consequences of different winding configurations. The validity of this analysis is examined experimentally. Motor heating tests are performed to determine the maximum in-service magnet temperatures and these results are presented. Design studies are conducted and a prototype motor using Neodymium magnets was built and tested. The design predictions and the test results are used to determine the suitability of Neodymium Iron Boron material for high performance Servo-motor applications

Cluster-based regime-switching AR for the EEM 2017 Wind Power Forecasting Competition

This paper describes the regime-switching autoregressive models used to win the EEM 2017 Wind Power Forecasting Competition. The competition required participants to produce daily forecast wind power production for a portfolio of wind farms from 2 to 38 hours-ahead based on historic generation and numerical weather prediction analysis data only. The regimes used in the methodology presented are defined on the previous day’s weather conditions using the k-medians clustering algorithm. Cross-validation is used to identify models with the best predictive power from a pool of candidate models. The final methodology produced a final weighted mean absolute error 4.5% lower than the second place team during the two-week competition period

A Parallel Branch and Bound Algorithm for the Maximum Labelled Clique Problem

The maximum labelled clique problem is a variant of the maximum clique problem where edges in the graph are given labels, and we are not allowed to use more than a certain number of distinct labels in a solution. We introduce a new branch-and-bound algorithm for the problem, and explain how it may be parallelised. We evaluate an implementation on a set of benchmark instances, and show that it is consistently faster than previously published results, sometimes by four or five orders of magnitude.Comment: Author-final version. Accepted to Optimization Letter

Traumatic Axonal Injury: Mechanisms and Translational Opportunities.

Traumatic axonal injury (TAI) is an important pathoanatomical subgroup of traumatic brain injury (TBI) and a major driver of mortality and functional impairment. Experimental models have provided insights into the effects of mechanical deformation on the neuronal cytoskeleton and the subsequent processes that drive axonal injury. There is also increasing recognition that axonal or white matter loss may progress for years post-injury and represent one mechanistic framework for progressive neurodegeneration after TBI. Previous trials of novel therapies have failed to make an impact on clinical outcome, in both TBI in general and TAI in particular. Recent advances in understanding the cellular and molecular mechanisms of injury have the potential to translate into novel therapeutic targets.CSH is supported by a Wellcome Trust PhD for Clinicians. MPC is funded by the John and Lucille van Geest Foundation. DKM is supported by a Senior Investigator Award from the National Institute for Health Research, UK (NIHR), by the Acute Brain Injury and Repair theme of the Cambridge NIHR Biomedical Research Centre, and a Framework Program 7 grant from the European Union (CENTER-TBI; Grant No: 602150)This is the final version of the article. It first appeared from Elsevier via https://doi.org/ 10.1016/j.tins.2016.03.00

The enzymes of the classical pentose phosphate pathway display differential activities in procyclic and bloodstream forms of Trypanosoma brucei

AbstractThe specific activities of each of the enzymes of the classical pentose phosphate pathway have been determined in both cultured procyclic and bloodstream forms of Trypanosoma brucei. Both forms contained glucose-6-phosphate dehydrogenase (EC 1.1.1.49), 6-phosphogluconolactonase (EC 3.1.1.31), 6-phosphogluconate dehydrogenase (EC 1.1.1.44), ribose-5-phosphate isomerase (EC 5.3.1.6) and transaldolase (EC 2.2.1.2). However, ribulose-5-phosphate 3′-epimerase (EC 5.1.3.1) and transketolase (EC 2.2.1.1) activities were detectable only in procyclic forms. These results clearly demonstrate that both forms of T. brucei can metabolize glucose via the oxidative segment of the classical pentose phosphate pathway in order to produce d-ribose-5-phosphate for the synthesis of nucleic acids and reduced NADP for other synthetic reactions. However, only procyclic forms are capable of using the non-oxidative segment of the classical pentose phosphate pathway to cycle carbon between pentose and hexose phosphates in order to produce d-glyceraldehyde 3-phosphate as a net product of the pathway. Both forms lack the key gluconeogenic enzyme, fructose-bisphosphatase (EC 3.1.3.11). Consequently, neither form should be able to engage in gluconeogenesis nor should procyclic forms be able to return any of the glyceraldehyde 3-phosphate produced in the pentose phosphate pathway to glucose 6-phosphate. This last specific metabolic arrangement and the restriction of all but the terminal steps of glycolysis to the glycosome may be the observations required to explain the presence of distinct cytosolic and glycosomal isoenzymes of glyceraldehyde-3-phosphate dehydrogenase and phosphoglycerate kinase. These same observations also may provide the basis for explaining the presence of cytosolic hexokinase and phosphoglucose isomerase without the presence of any cytosolic phosphofructokinase activity. The key enzymes of the Entner-Doudoroff pathway, 6-phosphogluconate dehydratase (EC 4.2.1.12) and 2-keto-3-deoxy-6-phosphogluconate aldolase (EC 4.1.2.14) were not detected in either procyclic or bloodstream forms of T. brucei

Nebular Line Emission During the Epoch of Reionization

Nebular emission lines associated with galactic HII regions carry information about both physical properties of the ionised gas and the source of ionising photons as well as providing the opportunity of measuring accurate redshifts and thus distances once a cosmological model is assumed. While nebular line emission has been extensively studied at lower redshift there are currently only few constraints within the epoch of reionisation (EoR, $z>6$), chiefly due to the lack of sensitive near-IR spectrographs. However, this will soon change with the arrival of the Webb Telescope providing sensitive near-IR spectroscopy covering the rest-frame UV and optical emission of galaxies in the EoR. In anticipation of Webb we combine the large cosmological hydrodynamical simulation Bluetides with photoionisation modelling to predict the nebular emission line properties of galaxies at $z=8\to 13$. We find good agreement with the, albeit limited, existing direct and indirect observational constraints on equivalent widths though poorer agreement with luminosity function constraints.Comment: 17 pages, accepted to MNRAS, significant modification from v1.0 data available at https://stephenmwilkins.github.io/BluetidesEmissionLines_Public