bluuebunny/crossref_metadata_2025 huggingface dataset:
Phenotypic divergence during speciation is inversely associated with differences in seasonal migration
Authors: Delmore Kira E. , Kenyon Haley L. , Germain Ryan R. , Irwin Darren E.
Published: November 2015

Differences in seasonal migration might promote reproductive isolation and differentiation by causing populations in migratory divides to arrive on the breeding grounds at different times and/or produce hybrids that take inferior migratory routes. We examined this question by quantifying divergence in song, colour, and morphology between sister pairs of North American migratory birds. We predicted that apparent rates of phenotypic differentiation would differ between pairs that do and do not form migratory divides. Consistent with this prediction, results from mixed effects models and Ornstein–Uhlenbeck models of evolution showed different rates of divergence between these groups; surprisingly, differentiation was greater among non-divide pairs. We interpret this finding as a result of variable rates of population blending and fusion between partially diverged forms. Ancient pairs of populations that subsequently fused are now observed as a single form, whereas those that did not fuse are observable as pairs and included in our study. We propose that fusion of two populations is more likely to occur when they have similar migratory routes and little other phenotypic differentiation that would cause reproductive isolation. By contrast, pairs with migratory divides are more likely to remain reproductively isolated, even when differing little in other phenotypic traits. These findings suggest that migratory differences may be one among several isolating barriers that prevent divergent populations from fusing and thereby increase the likelihood that they will continue differentiating as distinct species.
A symbiont's dispersal strategy: condition-dependent dispersal underlies predictable variation in direct transmission among hosts
Authors: Skelton James , Creed Robert P. , Brown Bryan L.
Published: November 2015

Direct horizontal transmission of pathogenic and mutualistic symbionts has profound consequences for host and symbiont fitness alike. While the importance of contact rates for transmission is widely recognized, the processes that underlie variation in transmission during contact are rarely considered. Here, we took a symbiont's perspective of transmission as a form of dispersal and adopted the concept of condition-dependent dispersal strategies from the study of free-living organisms to understand and predict variation in transmission in the cleaning symbiosis between crayfish and ectosymbiotic branchiobdellidan worms. Field study showed that symbiont reproductive success was correlated with host size and competition among worms for microhabitats. Laboratory experiments demonstrated high variability in transmission among host contacts. Moreover, symbionts were more likely to disperse when host size and competition for microhabitat created a fitness environment below a discrete minimum threshold. A predictive model based on a condition-dependent symbiont dispersal strategy correctly predicted transmission in 95% of experimental host encounters and the exact magnitude of transmission in 67%, both significantly better than predictions that assumed a fixed transmission rate. Our work provides a dispersal-based understanding of symbiont transmission and suggests adaptive symbiont dispersal strategies can explain variation in transmission dynamics and complex patterns of host infection.
Postharvest technology for advancing sustainable bioenergy production for food processing
Authors: Chimphango Annie F.A. , Görgens Johann F.
Published: November 2015

Purpose

– Agricultural food residues (agro-residues) receive low economic returns and experience disposal problems. The food production and processing is often not configured to supply agro-residues for production of bioenergy needed in food processing. The feasibility of utilising agro-residues through advances in postharvest technology for sustainable bioenergy conversion is reviewed. The paper aims to discuss this issue.

Design/methodology/approach

– Agro-residues from maize, sugarcane and potatoes in five African countries were assessed from secondary data to identify suitable conversion technologies, energy products and configurations of bioenergy plants for applications in postharvest food processing.

Findings

– Strategic alignment of postharvest technology to bioenergy production systems is vital to advancing both food production and bioenergy that benefit rural communities in Africa. High economic returns are possible when the bioenergy plants are either annexure to existing agro-processing operations or operate as a biorefinery.

Research limitations/implications

– Assessment of energy self-sufficiency of food production and processing systems is required.

Practical implications

– Agro-residues for bioenergy production require investments in infrastructure for storage, transportation and processing of the residues, and development of new risk management techniques.

Social implications

– The rural communities will be energy secure resulting in food security through reduced postharvest losses and increased agricultural productivity.

Originality/value

– The study stimulates innovative thinking in establishing sustainable bioenergy systems for food processes.
Yield variability in rainfed crops as influenced by climate variables
Authors: Arumugam Surendran , K.R. Ashok , Kulshreshtha. Suren N. , Vellangany Isaac , Govindasamy Ramu
Published: November 2015

Purpose

– This paper aims to explore the impact of climate change on yields and yield variances in major rainfed crops and measure possible changes in yields under projected climate changes in different agro-climatic zones of Tamil Nadu, India. Although many empirical studies report the influence of climate change on crop yield, only few address the effect on yield variances. Even in such cases, the reported yield variances were obtained through simulation studies rather than from actual observations. In this context, the present study analyzes the impact of climate change on crops yield and yield variance using the observed yields.

Design/methodology/approach

– The Just-Pope yield function (1978) is used to analyze the impact of climate change on mean yield and variance. The estimated coefficient from Just-Pope yield function and the projected climatic data for the year 2030 are incorporated to capture the projected changes in crop yield and variances.

Findings

– By the year 2030, the yield of pulses is estimated to decline in all the zones (Northeast, Northwest, Western, Cauvery delta, South and Southern zones), with significant declines in the Northeast zone (6.07 per cent), Cauvery delta zone (3.55 per cent) and South zone (3.54 per cent). Sorghum yield may suffer more in Western zone (2.63 per cent), Southern zone (1.92 per cent) and Northeast zone (1.62 per cent). Moreover, the yield of spiked millet is more likely to decrease in the Southern zone (1.39 per cent), Northeast zone (1.21 per cent) and Cauvery delta zone (0.24 per cent), and the yield of cotton may also decline in the Northeast zone (12.99 per cent), Northwest zone (8.05 per cent) and Western zone (2.10 per cent) of Tamil Nadu, India.

Originality/value

– The study recommends introducing appropriate crop insurance policies to address possible financial losses to the farmers. Prioritizing area-specific stress-tolerant crop varieties without complementing yield would sustain crops cultivation further.
Emissions and trade in Southeast and East Asian countries: a panel co-integration analysis
Authors: Ibrahim Mansor H. , Rizvi Syed Aun R.
Published: November 2015

Purpose

– The purpose of this paper is to analyse the implication of trade on carbon emissions in a panel of eight highly trading Southeast and East Asian countries, namely, China, Indonesia, South Korea, Malaysia, Hong Kong, The Philippines, Singapore and Thailand.

Design/methodology/approach

– The analysis relies on the standard quadratic environmental Kuznets curve (EKC) extended to include energy consumption and international trade. A battery of panel unit root and co-integration tests is applied to establish the variables’ stochastic properties and their long-run relations. Then, the specified EKC is estimated using the panel dynamic ordinary least square (OLS) estimation technique.

Findings

– The panel co-integration statistics verifies the validity of the extended EKC for the countries under study. Estimation of the long-run EKC via the dynamic OLS estimation method reveals the environmentally degrading effects of trade in these countries, especially in ASEAN and plus South Korea and Hong Kong.

Practical implications

– These countries are heavily dependent on trade for their development processes, and as such, their impacts on CO2 emissions would be highly relevant for assessing their trade policies, along the line of the gain-from-trade hypothesis, the race-to-the-bottom hypothesis and the pollution-safe-haven hypothesis.

Originality/value

– The analysis adds to existing literature by focusing on the highly trading nations of Southeast and East Asian countries. The results suggest that reassessment of trade policies in these countries is much needed and it must go beyond the sole pursuit of economic development via trade.
Managing Neotropical oil palm expansion to retain phylogenetic diversity
Authors: Prescott Graham W. , Gilroy James J. , Haugaasen Torbjørn , Medina Uribe Claudia A. , Foster William A. , Edwards David P.
Published: November 2015

The expansion of tropical agriculture is a major driver of the extinction crisis. A key question is whether biodiversity losses can be minimized by restricting future expansion to low‐productivity farmland and retaining forest fragments, especially in rapidly changing Neotropical landscapes.

We investigated these methods in the context of avian phylogenetic diversity, which summarizes the evolutionary history preserved within communities. Evidence suggests that phylogenetic diversity plays an important role in maintaining key ecosystem functions.

We collected data on avian communities in the Colombian Llanos, a region highlighted as being optimal for the expansion of oil palm, at the expense of existing habitats including forest remnants and improved cattle pastures.

PD, a measure of phylogenetic richness, and MPD, a measure of the phylogenetic distance between individuals in a community in deep evolutionary time, were significantly higher in forest than in oil palm or pasture, but did not differ significantly between oil palm and pasture. MNTD, a measure of distance between individuals in a community at the intra‐familial and intra‐generic level, was significantly higher in oil palm and pasture than in forest. However, median evolutionary distinctiveness (ED) was highest in pasture, partly due to the abundance of distinct waterbirds, but did not differ between oil palm and forest. PD in oil palm and pasture increased with the extent of remnant forest cover.

Synthesis and applications. The PD (a measure of phylogenetic richness) and MPD (a measure of the phylogenetic distance) of bird communities in this region can best be conserved by ensuring that new oil palm plantations replace pasturelands rather than forest. A secondary benefit of preserving forest would be the enhancement of PD in the surrounding agricultural landscape. This strategy will need to be coupled with measures to either reduce pasture demand or to intensify existing cattle production to ensure that forest is not replaced by pasture elsewhere.
Restraint of Trophoblast Invasion of the Uterus by Decorin: Role in Pre‐eclampsia
Authors: Nandi Pinki , Siddiqui Mohammad Fyyaz , Lala Peeyush K
Published: November 2015

Decorin (DCN) is a leucine‐rich, TGF‐β binding proteoglycan produced by mesenchymal cells including chondrocytes, dermal fibroblasts, and uterine decidual cells. It exerts multiple physiological functions including collagen fibrillogenesis, myogenesis, angiostasis, and restraining placental invasiveness. We discovered that decidua‐derived DCN restrains proliferation, migration, and invasion of extravillous trophoblast (EVT) cells of the human placenta in a TGF‐β‐independent manner. These functions were differentially mediated by binding of DCN to multiple tyrosine kinase receptors (TKR) including EGFR, IGFR1, and VEGFR2. DCN blocked VEGFR‐2 dependent EVT cell migration and endovascular differentiation by inhibiting P38MAPK and ERK1/2 pathways.We identified the avid VEGFR2 binding site in DCN protein as a 12 amino acids (LGTNPLKSSGIE) span in the Leucine‐rich‐repeat (LRR) 5 region of domain III. A single amino acid mutation (substitution of K to A) of DCN at this site abrogated VEGFR‐2‐ dependent DCN actions. Also, DCN mRNA expression, measured with in situ hybridization, was selectively upregulated in decidual cells in placentas from mothers suffering from pre‐eclampsia (PE), whereas the expression levels remained unchanged in chorionic villus mesenchymal cells. This difference between PE and control placentas was present at all gestational ages, indicating the pathogenic role of DCN in PE. We hypothesize that increased blood DCN levels could be a candidate biomarker for PE.
P2Y12 receptor blockade synergizes strongly with nitric oxide and prostacyclin to inhibit platelet activation
Authors: Chan Melissa V. , Knowles Rebecca B. M. , Lundberg Martina H. , Tucker Arthur T. , Mohamed Nura A. , Kirkby Nicholas S. , Armstrong Paul C. J. , Mitchell Jane A. , Warner Timothy D.
Published: November 2015

Aims

In vivo platelet function is a product of intrinsic platelet reactivity, modifiable by dual antiplatelet therapy (DAPT), and the extrinsic inhibitory endothelial mediators, nitric oxide (NO) and prostacyclin (PGI2), that are powerfully potentiated by P2Y12 receptor blockade. This implies that for individual patients endothelial mediator production is an important determinant of DAPT effectiveness. Here, we have investigated this idea using platelets taken from healthy volunteers treated with anti‐platelet drugs.

Methods

Three groups of male volunteers (n = 8) received either prasugrel (10 mg), aspirin (75 mg) or DAPT (prasugrel + aspirin) once daily for 7 days. Platelet reactivity in the presence of diethylammonium (Z)‐1‐(N,N‐diethylamino)diazen‐1‐ium‐1,2‐diolate (DEA/NONOate) and PGI2 was studied before and following treatment.

Results

Ex vivo, PGI2 and/or DEA/NONOate had little inhibitory effect on TRAP‐6‐induced platelet reactivity in control conditions. However, in the presence of DAPT, combination of DEA/NONOate + PGI2 reduced platelet aggregation (74 ± 3% to 19 ± 6%, P < 0.05). In vitro studies showed even partial (25%) P2Y12 receptor blockade produced a significant (67 ± 2% to 39 ± 10%, P < 0.05) inhibition when DEA/NONOate + PGI2 was present.

Conclusions

We have demonstrated that PGI2 and NO synergize with P2Y12 receptor antagonists to produce powerful platelet inhibition. Furthermore, even with submaximal P2Y12 blockade the presence of PGI2 and NO greatly enhances platelet inhibition. Our findings highlight the importance of endothelial mediator in vivo modulation of P2Y12 inhibition and introduces the concept of refining ex vivo platelet function testing by incorporating an assessment of endothelial function to predict thrombotic outcomes better and adjust therapy to prevent adverse outcomes in individual patients.
Ready to Fight: Reliable Predictors of Attack in a Cooperatively Breeding, Non‐Passerine Bird
Authors: Grieves Leanne A , Logue David M , Quinn Jim S
Published: November 2015

Signal reliability is a major focus of animal communication research. Aggressive signals are ideal for measuring signal reliability because the signal referent – attack or no attack – can be measured unambiguously. Signals of aggressive intent occur at elevated rates in aggressive contexts, predict subsequent aggression by the signaler, and elicit appropriate responses from receivers. We tested the ‘predictive criterion’ in smooth‐billed anis, Crotophaga ani, by broadcasting one of two playback types (‘ahnee’ calls only or ‘ahnee + hoot’ calls), presenting a taxidermic mount, and observing the animals’ behavior. Based on the hypotheses that ‘hoot’ calls and ‘throat‐inflation’ displays signal aggressive intent, we predicted that they would be associated with attack, and that signaling rate would increase over the time period leading up to an attack. Indeed, both hoots and throat‐inflation displays reliably predicted attack. The second prediction, that signaling rate increases in the time leading up to attack, was strongly supported for throat‐inflation displays, which increased over the pre‐attack period in both treatments. Hoots increased over the pre‐attack period in ahnee playbacks but not in ahnee + hoot playbacks. Hierarchical signaling systems are characterized by early, less‐reliable predictors of attack, and later, more reliable predictors of attack. During both natural and simulated interactions, the more‐reliable throat‐inflation display tended to precede the less‐reliable hoot call, suggesting that this signaling system is not hierarchical. In a comparison of 11 putative signals of aggressive intent in birds, the throat‐inflation display had the second highest mutual information (reduction in uncertainty) among visual signals and non‐passerine signals while hoots had below‐average mutual information. Natural observations indicate that both hoots and throat‐inflation displays occur in the context of aggressive between‐group encounters, and hoots also occur during within‐group interactions. Throat‐inflation displays appear to be reliable indicators of aggressive intent, but the function of hoot calls is less clear.
Sexual Selection in Black Morph Girardinus metallicus (Pisces: Poeciliidae): Females Can Spot a Winner (But We Cannot)
Authors: Kolluru Gita R. , Castillo Crystal , Hendrickson Michele , Hughes Meghan , Krause Paris , LePiane Krista , McCann Colleen , Pavia Emily , Porter Colin , Rodriguez Rodet , Rodriguez‐Cabrera Tomas , Scott Ellen , Willrodt McCall , Bertram Susan M.
Published: November 2015

Male–male competition may interfere with the ability of females to choose mates by interrupting courtship or by favoring highly aggressive males who may damage females during mating attempts. Alternatively, females may benefit by mating with dominant males, and female choice and male–male competition may therefore act in unison. The same traits, including aggressiveness, may indicate male quality to females and to rivals. We investigated sexual selection in the black morph of the endemic Cuban poeciliid fish, Girardinus metallicus, to ascertain the links between morphological and behavioral traits and success in intra‐ and intersexual selection. Males conspicuously exhibit their black ventral surface and gonopodium to females during courtship. Dichotomous choice tests revealed female association preferences for certain males, and those same males were more successful in monopolizing access to females when the fish were allowed to directly interact. Dominant males followed, courted, and copulated with females more than subordinate males within a pair, and it appears that females could either assess dominance based on cues we did not measure, or could influence subsequent mating success by their behavior during the dichotomous choice trials. There was an interaction between black status (i.e., whether the male in each pair had more or less ventral black coloration than the other male in that pair) and dominance, such that low‐black dominant males courted early and then shifted to following females, whereas high‐black dominant males courted far more later in the observation period. These results hint at the importance for sexual selection of the interplay between a static morphological trait (black coloration) and a dynamic behavioral trait (aggressiveness), but the functional significance of the courtship display remains a mystery.
Integrating theory into disturbance interaction experiments to better inform ecosystem management
Authors: Foster Claire N. , Sato Chloe F. , Lindenmayer David B. , Barton Philip S.
Published: November 2015

Managing multiple, interacting disturbances is a key challenge to biodiversity conservation, and one that will only increase as global change drivers continue to alter disturbance regimes. Theoretical studies have highlighted the importance of a mechanistic understanding of stressor interactions for improving the prediction and management of interactive effects. However, many conservation studies are not designed or interpreted in the context of theory and instead focus on case‐specific management questions. This is a problem as it means that few studies test the relationships highlighted in theoretical models as being important for ecological management. We explore the extent of this problem among studies of interacting disturbances by reviewing recent experimental studies of the interaction between fire and grazing in terrestrial ecosystems. Interactions between fire and grazing can occur via a number of pathways; one disturbance can modify the other's likelihood, intensity or spatial distribution, or one disturbance can alter the other's impacts on individual organisms. The strength of such interactions will vary depending on disturbance attributes (e.g. size or intensity), and this variation is likely to be nonlinear. We show that few experiments testing fire–grazing interactions are able to identify the mechanistic pathway driving an observed interaction, and most are unable to detect nonlinear effects. We demonstrate how these limitations compromise the ability of experimental studies to effectively inform ecological management. We propose a series of adjustments to the design of disturbance interaction experiments that would enable tests of key theoretical pathways and provide the deeper ecological understanding necessary for effective management. Such considerations are relevant to studies of a broad range of ecological interactions and are critical to informing the management of disturbance regimes in the context of accelerating global change.
Climate change and larval transport in the ocean: fractional effects from physical and physiological factors
Authors: Kendall Matthew S. , Poti Matt , Karnauskas Kristopher B.
Published: November 2015

Changes in larval import, export, and self‐seeding will affect the resilience of coral reef ecosystems. Climate change will alter the ocean currents that transport larvae and also increase sea surface temperatures (SST), hastening development, and shortening larval durations. Here, we use transport simulations to estimate future larval connectivity due to: (1) physical transport of larvae from altered circulation alone, and (2) the combined effects of altered currents plus physiological response to warming. Virtual larvae from islands throughout Micronesia were moved according to present‐day and future ocean circulation models. The Hybrid Coordinate Ocean Model (HYCOM) spanning 2004–2012 represented present‐day currents. For future currents, we altered HYCOM using analysis from the National Center for Atmospheric Research Community Earth System Model, version 1‐Biogeochemistry, Representative Concentration Pathway 8.5 experiment. Based on the NCAR model, regional SST is estimated to rise 2.74 °C which corresponds to a ~17% decline in larval duration for some taxa. This reduction was the basis for a separate set of simulations. Results predict an increase in self‐seeding in 100 years such that 62–76% of islands experienced increased self‐seeding, there was an average domainwide increase of ~1–3% points in self‐seeding, and increases of up to 25% points for several individual islands. When changed currents alone were considered, approximately half (i.e., random) of all island pairs experienced decreased connectivity but when reduced PLD was added as an effect, ~65% of connections were weakened. Orientation of archipelagos relative to currents determined the directional bias in connectivity changes. There was no universal relationship between climate change and connectivity applicable to all taxa and settings. Islands that presently export large numbers of larvae but that also maintain or enhance this role into the future should be the focus of conservation measures that promote long‐term resilience of larval supply.
Circulating and myometrial markers of oxidative stress in pregnant women with fetal growth restriction
Authors: Biberoglu Ebru , Biberoglu Kutay , Kirbas Ayse , Daglar Korkut , Genc Metin , Avci Aslihan , Danisman Nuri
Published: November 2015

Aim

The objective of this study was to identify the relationship between fetal growth restriction (FGR) and oxidative stress. The mechanisms that protect against oxidative stress in the local microenvironment were investigated by comparing the activities of the markers, both in the circulation and myometrium.

Materials and Methods

Myometrial tissue and serum levels of malondialdehyde (MDA), xanthine oxidase (XO), catalase (CAT) and superoxide dismutase (SOD) markers were measured in 20 FGR and 20 healthy pregnancies.

Results

The mean duration of gestation at delivery was shorter (P = 0003) and the mean birthweight was lower P < 0001) in the FGR study group compared with the control group, as expected. While MDA and CAT concentrations were higher in the serum (P < 0.02 and P < 0.01, respectively), but lower in the myometrial samples (P < 0.01) in the FGR versus the control group, XO and myometrial SOD values were comparable in both groups.

Conclusions

Although our data demonstrated that FGR is associated with oxidative stress, the exact role and mechanism of the oxidant and antioxidant imbalance is obscure. We speculate that despite limited local synthesis of CAT, effective and efficient removal of MDA in the uterine environment explains high MDA and CAT serum concentrations in women with FGR. Alternatively, a well‐functioning myometrial system could rescue the fetus from reactive oxygen species, as demonstrated by lowered MDA and depleted CAT resulting from hyperconsumption. Elevated serum MDA and CAT levels in the serum may reflect the ‘spillover’ of these markers from the uterus to the circulation.
Commodity Fetishism and Consumer Senses: Turn‐of‐the‐Twentieth‐Century Consumer Activism in the United States and England
Authors: Skotnicki Tad
Published: November 2015

At the turn of the twentieth century, the National Consumers’ League, the Co‐operative Wholesale Society, and the Women's Co‐operative Guild encouraged people to become ethical consumers. I argue that we can explain their common strategies by invoking commodity fetishism. By casting their consumer activism as a practical response to the fetish of commodities, we explain: 1) activists’ use of sensory techniques – both figurative and literal – to connect producers, commodities, and consumers and 2) their commitment to the ethical power of the senses. This account reveals the virtues of commodity fetishism as a tool for understanding the dynamics of consumer activism.
An Experimental Investigation of How Judicial Elections Affect Public
Faith in the Judicial System
Authors: Nownes Anthony J. , Glennon Colin
Published: November 2015

Judicial scholars have often speculated about the impact of elections on
the administration of justice in the state courts. Yet relatively little
research has concerned itself with public perceptions of state court
selection methods. Of particular interest is the concept of legitimacy. Do
elections negatively affect public perceptions of judicial legitimacy?
Bonneau and Hall (2009) and Gibson (2012) answer this question with an
emphatic “No.” Judicial elections, these studies show, are not uniquely
troublesome for perceptions of institutional legitimacy. This article aims
to extend the findings of Bonneau and Hall and Gibson via a laboratory
experiment on the effects of elections on public perceptions of judicial
legitimacy. In the end, we find that because elections preempt the use of
the other main selection method—appointment—they actually enhance
perceptions of judicial legitimacy rather than diminish them.
Evaluating genomic divergence and parallelism in replicate ecomorphs from young and old cichlid adaptive radiations
Authors: McGee Matthew D. , Neches Russell Y. , Seehausen Ole
Published: November 2015

Comparative genomic studies of closely related species typically focus on single species pairs at one given stage of divergence. That makes it difficult to infer the continuum of evolutionary process during speciation and beyond. Here, we use whole‐genome resequencing to examine genomic patterns of divergence in three sympatric cichlid species pairs with very similar functional and ecological differentiation, but different ages. We find a strong signature of increasing genomic divergence with time in both the mitochondrial genome and the nuclear genome. In contrast to many other systems, we find that in these cichlids, regions of elevated relative differentiation also exhibit increased absolute differentiation. We detect a signature of convergent evolution in a comparison of outlier regions across all three species pair comparisons, but the extent of it is modest, and regions that are strongly divergent in any one pair tend to be only slightly elevated in the other pairs, consistent with a repeatable but polygenic basis of traits that characterize the ecomorphs. Our results suggest that strong functional phenotypic differentiation, as seen in all three species pairs, is generally associated with a clear signature of genomic divergence, even in the youngest species pair.
Scope of practice of optometrists working in the UK Hospital Eye Service: a national survey
Authors: Harper Robert , Creer Rosalind , Jackson Jonathan , Ehrlich Daniel , Tompkin Andrew , Bowen Michael , Tromans Cindy
Published: November 2015

Purpose

The role of the optometrist in the Hospital Eye Service (HES) has undergone significant development in recent years to include extended areas of clinical practice more traditionally undertaken by ophthalmologists, commensurate with a growing demand for increased capacity in ophthalmic services. In this report, we present the findings from a national survey of the scope of practice of optometrists working in the UK HES.

Methods

A survey was designed to incorporate questions on the provision of core services before seeking detailed information on the scope of practice within extended roles to include: ophthalmic sub‐specialist areas where optometrists currently practice; the undertaking of specific procedures within these services; the relative autonomy of practice within these extended roles; and the training and accreditation requirements for working within extended roles. SurveyMonkey was used to disseminate the survey to the head of optometry in 79 HES units throughout the UK.

Results

Responses were received from 70 of the 79 (89%) survey invitations. A substantial majority of respondents (N = 67/70, 96%) indicated that optometrists undertook extended roles. Glaucoma is the leading extended role service provided by optometrists (92% of respondents providing extended role services), with roles in macula (71%), medical retina/diabetes (67%), cataract (55%) and corneal services (55%) also being relatively common. A wide variety of clinical procedures or interventions are undertaken as part of these services, which for a small number of optometrists now also includes the undertaking of specific laser procedures. There is evidence for a significant degree of autonomy within these extended roles. The primary mode of training is an ‘apprentice’ model, incorporating sessions worked under supervision in ophthalmology clinics. Methods of accreditation for optometric participation in extended role services are varied.

Conclusions

While optometrists working within the UK HES continue to undertake the traditional clinical roles of refraction, clinically necessary contact lenses, and low vision rehabilitation, it is clear that these professionals now undertake a wide range of extended clinical roles, with a transformed scope of practice now incorporating diverse roles traditionally undertaken by medical practitioners.
Efficient Steady-State Computation for Wear of Multimaterial Composites
Authors: Feppon Florian , Sidebottom Mark A. , Michailidis Georgios , Krick Brandon A. , Vermaak Natasha
Published: November 2015

Traditionally, iterative schemes have been used to predict evolving material profiles under abrasive wear. In this work, more efficient continuous formulations are presented for predicting the wear of tribological systems. Following previous work, the formulation is based on a two parameter elastic Pasternak foundation model. It is considered as a simplified framework to analyze the wear of multimaterial surfaces. It is shown that the evolving wear profile is also the solution of a parabolic partial differential equation (PDE). The wearing profile is proven to converge to a steady-state that propagates with constant wear rate. A relationship between this velocity and the inverse rule of mixtures or harmonic mean for composites is derived. For cases where only the final steady-state profile is of interest, it is shown that the steady-state profile can be accurately and directly determined by solving a simple elliptic differential system—thus avoiding iterative schemes altogether. Stability analysis is performed to identify conditions under which an iterative scheme can provide accurate predictions and several comparisons between iterative and the proposed formulation are made. Prospects of the new continuous wear formulation and steady-state characterization are discussed for advanced optimization, design, manufacturing, and control applications.
Effects of Substrate Bias on Tribological Properties of Diamondlike Carbon Thin Films Deposited Via Microwave-Excited Plasma-Enhanced Chemical Vapor Deposition
Authors: Win Khun Nay , Neville Anne , Kolev Ivan , Zhao Hongyuan
Published: November 2015

In this study, the structure and tribological performance of the diamondlike carbon (DLC) films were related to deposition parameters. The feasibility of the microwave-excited plasma-enhanced chemical vapor deposition (μW-PECVD) as a process to produce good quality DLC films was the focus. The DLC films were deposited on the steel substrates with a tungsten carbide interlayer via μW-PECVD. The negative substrate bias used during the film deposition was varied. The Raman results revealed that the increased negative substrate bias increased the sp3 bonding in the DLC films as a result of the increased kinetic energy of film-forming ions during the film deposition. The tribological results clearly indicated that the friction and wear of the DLC-coated steel samples against a 100Cr6 steel ball significantly decreased with increased negative substrate bias due to the significantly improved wear resistance of the DLC films.
Sources and Propagation of Nonlinearity in a Vibration Isolator With Geometrically Nonlinear Damping
Authors: Carranza J. C. , Brennan M. J. , Tang B.
Published: November 2015

In this paper, the behavior of a single degree-of-freedom (SDOF) passive vibration isolation system with geometrically nonlinear damping is investigated, and its displacement and force transmissibilities are compared with that of a linear system. The nonlinear system is composed of a linear spring and a linear viscous damper which are connected to a mass so that the damper is perpendicular to the spring. The system is excited by a harmonic force applied to the mass or a displacement of the base in the direction of the spring. The transmissibilities of the nonlinear isolation system are calculated using analytical expressions for small amplitudes of excitation and by using numerical simulations for high amplitude of excitation. When excited with a harmonic force, the forces transmitted through the spring and the damper are analyzed separately by decomposing the forces in terms of their harmonics. This enables the effects of these elements to be studied and to determine how they contribute individually to the nonlinear behavior of the system as a whole. For single frequency excitation, it is shown that the nonlinear damper causes distortion of the velocity of the suspended mass by generating higher harmonic components, and this combines with the time-varying nature of the damping in the system to severely distort the force transmitted though the damper. The distortion of the force transmitted through the spring is much smaller than that through the damper.
Super‐resolution reconstruction in frequency, image, and wavelet domains to reduce through‐plane partial voluming in MRI
Authors: Gholipour Ali , Afacan Onur , Aganj Iman , Scherrer Benoit , Prabhu Sanjay P. , Sahin Mustafa , Warfield Simon K.
Published: November 2015

Purpose:

To compare and evaluate the use of super‐resolution reconstruction (SRR), in frequency, image, and wavelet domains, to reduce through‐plane partial voluming effects in magnetic resonance imaging.

Methods:

The reconstruction of an isotropic high‐resolution image from multiple thick‐slice scans has been investigated through techniques in frequency, image, and wavelet domains. Experiments were carried out with thick‐slice T2‐weighted fast spin echo sequence on the Academic College of Radiology MRI phantom, where the reconstructed images were compared to a reference high‐resolution scan using peak signal‐to‐noise ratio (PSNR), structural similarity image metric (SSIM), mutual information (MI), and the mean absolute error (MAE) of image intensity profiles. The application of super‐resolution reconstruction was then examined in retrospective processing of clinical neuroimages of ten pediatric patients with tuberous sclerosis complex (TSC) to reduce through‐plane partial voluming for improved 3D delineation and visualization of thin radial bands of white matter abnormalities.

Results:

Quantitative evaluation results show improvements in all evaluation metrics through super‐resolution reconstruction in the frequency, image, and wavelet domains, with the highest values obtained from SRR in the image domain. The metric values for image‐domain SRR versus the original axial, coronal, and sagittal images were PSNR = 32.26 vs 32.22, 32.16, 30.65; SSIM = 0.931 vs 0.922, 0.924, 0.918; MI = 0.871 vs 0.842, 0.844, 0.831; and MAE = 5.38 vs 7.34, 7.06, 6.19. All similarity metrics showed high correlations with expert ranking of image resolution with MI showing the highest correlation at 0.943. Qualitative assessment of the neuroimages of ten TSC patients through in‐plane and out‐of‐plane visualization of structures showed the extent of partial voluming effect in a real clinical scenario and its reduction using SRR. Blinded expert evaluation of image resolution in resampled out‐of‐plane views consistently showed the superiority of SRR compared to original axial and coronal image acquisitions.

Conclusions:

Thick‐slice 2D T2‐weighted MRI scans are part of many routine clinical protocols due to their high signal‐to‐noise ratio, but are often severely affected by through‐plane partial voluming effects. This study shows that while radiologic assessment is performed in 2D on thick‐slice scans, super‐resolution MRI reconstruction techniques can be used to fuse those scans to generate a high‐resolution image with reduced partial voluming for improved postacquisition processing. Qualitative and quantitative evaluation showed the efficacy of all SRR techniques with the best results obtained from SRR in the image domain. The limitations of SRR techniques are uncertainties in modeling the slice profile, density compensation, quantization in resampling, and uncompensated motion between scans.
Agreement Between Investigators Using Paired-Pulse Transcranial Magnetic Stimulation to Assess Quadriceps Intracortical Excitability
Authors: Thomas Abbey C. , Pietrosimone Brian G. , Bayer Carter J.
Published: November 2015

Context: Transcranial magnetic stimulation (TMS) may provide important information regarding the corticospinal mechanisms that may contribute to the neuromuscular activation impairments. Paired-pulse TMS testing is a reliable method for measuring intracortical facilitation and inhibition; however, little evidence exists regarding agreement of these measures in the quadriceps. Objective: To determine the between-sessions and interrater agreement of intracortical excitability (short- and long-interval intracortical inhibition [SICI, LICI] and intracortical facilitation [ICF]) in the dominant-limb quadriceps. Design: Reliability study. Setting: Research laboratory. Participants: 13 healthy volunteers (n = 6 women; age 24.7 ± 2.1 y; height 1.7 ± 0.1 m; mass 77.1 ± 17.4 kg). Intervention: Participants completed 2 TMS sessions separated by 1 wk. Main Outcome Measures: Two investigators measured quadriceps SICI, LICI, and ICF at rest and actively (5% of maximal voluntary isometric contraction). All participants were seated in a dynamometer with the knee flexed to 90°. Intracortical-excitability paradigm and investigator order were randomized. Bland-Altman analyses were used to establish agreement. Results: Agreement was stronger between sessions within a single investigator than between investigators and for active than resting measures. Agreement was strongest for resting SICI and active ICF and LICI between sessions for each investigator. Conclusions: Quadriceps intracortical excitability may be measured longitudinally by a single investigator, though active muscle contraction should be elicited during testing.
The Human Adenovirus Type 5 E4orf6/E1B55K E3 Ubiquitin Ligase Complex Enhances E1A Functional Activity
Authors: Dallaire Frédéric , Schreiner Sabrina , Blair G. Eric , Dobner Thomas , Branton Philip E. , Blanchette Paola
Published: November 2015

Following our demonstration that adenovirus E3 ubiquitin ligase formed by the viral E4orf6 and E1B55K proteins is able to mimic the activation of E2F by E1A, we conducted a series of studies to determine if this complex might also promote the ability of E1A to do so. We found that the complex both significantly stabilizes E1A proteins and also enhances their ability to activate E2F. This finding is of significance because it represents an entirely new function for the ligase in regulating adenovirus replication by enhancing the action of E1A products.
Statistical physics in the oeuvre of Chen Ning Yang
Authors: Fisher Michael E.
Published: November 2015

Starting from his early years selected contributions of C. N. Yang to statistical mechanics are highlighted and the physics to which they led is briefly reviewed.
Plasma kinetic coefficients with account for relaxation processes
Authors: Gorev V. N. , Sokolovsky A. I.
Published: November 2015

The hydrodynamics of a completely ionized two-component electron–ion plasma is investigated on the basis of the Landau kinetic equation with account for component temperature and velocity relaxation. The term relaxation is understood here in a narrow sense as a process which can take place in a spatially homogeneous system. The investigation is made on the basis of a generalized Chapman–Enskog method. The relaxation is investigated in the vicinity of the standard hydrodynamic state of plasma: the deviations of the component temperatures and velocities from their standard hydrodynamic values are considered to be small. The integral equations for the component distribution functions are investigated in a perturbation theory in small gradients and small relaxation parameters. The component distribution functions of the first-order both in gradients and in relaxation parameters are calculated. Relaxation corrections to the energy and momentum fluxes and to the kinetic coefficients of the standard hydrodynamic state of the system are obtained.
Closed analytical solutions of Bohr Hamiltonian with Manning-Rosen potential model
Authors: Chabab M. , Lahbas A. , Oulne M.
Published: November 2015

In the present paper, we have obtained closed analytical expressions for eigenvalues and eigenfunctions of the Bohr Hamiltonian with the Manning–Rosen potential for [Formula: see text]unstable nuclei as well as exactly separable rotational ones with [Formula: see text]. Some heavy nuclei with known [Formula: see text] and [Formula: see text] bandheads have been fitted by using two parameters in the [Formula: see text]unstable case and three parameters in the axially symmetric prolate deformed one. A good agreement with experimental data has been achieved.
Forced Vibration of Surface Foundation on Viscoelastic Isotropic Multi-Layered Stratum
Authors: Chen Lin
Published: November 2015

A numerical approach is presented for analyzing the forced vibration of a rigid surface foundation. In the analysis, the foundation is discretized into a number of sub square-elements. The dynamic response within each sub-element is described by the Green’s function, which is obtained by the Fourier–Bessel transform and the precise integration method (PIM). Then, a system of linear algebraic equation in terms of the contact forces within each sub-element is derived, which leads to the desired dynamic impedance functions of the foundation. Numerical results are obtained for the foundation not only with a simple geometry, such as circular one, but also with irregular shapes. Comparisons between the results obtained by the proposed approach and the thin layered method are made, for which good agreement is achieved. Also, parametric studies are performed on the dynamic response of the foundation, considering the effects of the material damping, stratum depth, Poisson’s ratio and the contact condition of the soil–foundation interface. Several conclusions are drawn concerning the significance of each parameter. Further application of the method can be easily extended to the analysis of a foundation on a viscoelastic anisotropic multi-layered stratum because no further complexity is introduced except the constitutive matrix needs to be modified.
Dynamic and Reactive Walking for Humanoid Robots Based on Foot Placement Control
Authors: Castano Juan Alejandro , Li Zhibin , Zhou Chengxu , Tsagarakis Nikos , Caldwell Darwin
Published: November 2015

This paper presents a novel online walking control that replans the gait pattern based on our proposed foot placement control using the actual center of mass (COM) state feedback. The analytic solution of foot placement is formulated based on the linear inverted pendulum model (LIPM) to recover the walking velocity and to reject external disturbances. The foot placement control predicts where and when to place the foothold in order to modulate the gait given the desired gait parameters. The zero moment point (ZMP) references and foot trajectories are replanned online according to the updated foothold prediction. Hence, only desired gait parameters are required instead of predefined or fixed gait patterns. Given the new ZMP references, the extended prediction self-adaptive control (EPSAC) approach to model predictive control (MPC) is used to minimize the ZMP response errors considering the acceleration constraints. Furthermore, to ensure smooth gait transitions, the conditions for the gait initiation and termination are also presented. The effectiveness of the presented gait control is validated by extensive disturbance rejection studies ranging from single mass simulation to a full body humanoid robot COMAN in a physics based simulator. The versatility is demonstrated by the control of reactive gaits as well as reactive stepping from standing posture. We present the data of the applied disturbances, the prediction of sagittal/lateral foot placements, the replanning of the foot/ZMP trajectories, and the COM responses.