Collaborative multidisciplinary learning : quantity surveying students’ perspectives

The construction industry is highly fragmented and is known for its adversarial culture, culminating in poor quality projects not completed on time or within budget. The aim of this study is thus to guide the design of QS programme curricula in order to help students develop the requisite knowledge and skills to work more collaboratively in their multi-disciplinary future workplaces. A qualitative approach was considered appropriate as the authors were concerned with gathering an initial understanding of what students think of multi-disciplinary learning. The data collection method used was a questionnaire which was developed by the Behaviours4Collaboration (B4C) team. Knowledge gaps were still found across all the key areas where a future QS practitioner needs to be collaborative (either as a project contributor or as a project leader) despite the need for change instigated by the multi-disciplinary (BIM) education revolution. The study concludes that universities will need to be selective in teaching, and innovative in reorienting, QS education so that a collaborative BIM education can be effected in stages, increasing in complexity as the students’ technical knowledge grows. This will help students to build the competencies needed to make them future leaders. It will also support programme currency and delivery

Multi-Frequency Precise Point Positioning using GPS and Galileo data with smoothed ionospheric corrections

The poor signal visibility and continuity associated with urban environments together with the slow convergence/reconvergence time of Precise Point Positioning (PPP), usually makes PPP unsuitable for land navigation in cities. However, results based on simulated open areas demonstrated that, once Galileo reaches final operational capability, PPP convergence time will be cut in a half using dual-constellation GPS/Galileo observations. Therefore, it might be possible to extend the applicability of PPP to land navigation in certain urban areas. Preliminary results, based on simulations, showed that GPS/Galileo PPP is possible where buildings are relatively short and satellites minimum visibility requirement is met for most of the time. In urban environments, signal discontinuity and reconvergence still represent the major problem for traditional PPP, which is based on the ionosphere-free combination of two-frequency pseudo-range and carrier phase. An alternative method to mitigate the ionosphere delay is proposed in order to ensure the best positioning performance from multi-frequency PPP. Instead of using the ionosphere-free combination, here low noise dual- or triple-frequency pseudo-range combinations are corrected with ionosphere delay information coming from federated carrier smoothing (Hatch) iono-estimation filters for each satellite. This method provides faster re- convergence time and ensures the best possible positioning performance from the Galileo Alternative BOC modulation in multi-frequency PPP. Indeed, even though Galileo E5 has small tracking noise and excellent multipath rejection, its PPP positioning performance is limited by the influence of E1 signal errors in the ionosphere-free combination, degrading the quality of the measurements

Contrasting evolution of virulence and replication rate in an emerging bacterial pathogen

This is the final version. Available on open access from the National Academy of Sciences via the DOI in this recordData deposition: Data reported in this paper have been deposited in Dryad Digital Repository (doi:10.5061/dryad.km3109k).Host resistance through immune clearance is predicted to favor pathogens that are able to transmit faster and are hence more virulent. Increasing pathogen virulence is, in turn, typically assumed to be mediated by increasing replication rates. However, experiments designed to test how pathogen virulence and replication rates evolve in response to increasing host resistance, as well as the relationship between the two, are rare and lacking for naturally evolving host–pathogen interactions. We inoculated 55 isolates of Mycoplasma gallisepticum, collected over 20 y from outbreak, into house finches (Haemorhous mexicanus) from disease-unexposed populations, which have not evolved protective immunity to M. gallisepticum. We show using 3 different metrics of virulence (body mass loss, symptom severity, and putative mortality rate) that virulence has increased linearly over >150,000 bacterial generations since outbreak (1994 to 2015). By contrast, while replication rates increased from outbreak to the initial spread of resistance (1994 to 2004), no further increases have occurred subsequently (2007 to 2015). Finally, as a consequence, we found that any potential mediating effect of replication rate on virulence evolution was restricted to the period when host resistance was initially increasing in the population. Taken together, our results show that pathogen virulence and replication rates can evolve independently, particularly after the initial spread of host resistance. We hypothesize that the evolution of pathogen virulence can be driven primarily by processes such as immune manipulation after resistance spreads in host populations.Natural Environment Research Council (NERC

Rapid antagonistic coevolution in an emerging pathogen and its vertebrate host

This is the final version of the article. Available from Elsevier via the DOI in this record.Host-pathogen coevolution is assumed to play a key role in eco-evolutionary processes, including epidemiological dynamics and the evolution of sexual reproduction [1-4]. Despite this, direct evidence for host-pathogen coevolution is exceptional [5-7], particularly in vertebrate hosts. Indeed, although vertebrate hosts have been shown to evolve in response to pathogens or vice versa [8-12], there is little evidence for the necessary reciprocal changes in the success of both antagonists over time [13]. Here, we generate a time-shift experiment to demonstrate adaptive, reciprocal changes in North American house finches (Haemorhous mexicanus) and their bacterial pathogen, Mycoplasma gallisepticum [14-16]. Our experimental design is made possible by the existence of disease-exposed and unexposed finch populations, which were known to exhibit equivalent responses to experimental inoculation until the recent spread of genetic resistance in the former [14, 17]. While inoculation with pathogen isolates from epidemic outbreak caused comparable sub-lethal eye-swelling in hosts from exposed (hereafter adapted) and unexposed (hereafter ancestral) populations, inoculation with isolates sampled after the spread of resistance were threefold more likely to cause lethal symptoms in hosts from ancestral populations. Similarly, the probability that pathogens successfully established an infection in the primary host and, before inducing death, transmitted to an uninfected sentinel was highest when recent isolates were inoculated in hosts from ancestral populations and lowest when early isolates were inoculated in hosts from adapted populations. Our results demonstrate antagonistic host-pathogen coevolution, with hosts and pathogens displaying increased resistance and virulence in response to each other over time.This research was supported by a Natural Environment Research Council standard grant to C.B. (NE/M00256X)

Evolutionary innovation and diversification of carotenoid-based pigmentation in finches

© 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution. The ornaments used by animals to mediate social interactions are diverse, and by reconstructing their evolutionary pathways we can gain new insights into the mechanisms underlying ornamental innovation and variability. Here, we examine variation in plumage carotenoids among the true finches (Aves: Fringillidae) using biochemical and comparative phylogenetic analyses to reconstruct the evolutionary history of carotenoid states and evaluate competing models of carotenoid evolution. Our comparative analyses reveal that the most likely ancestor of finches used dietary carotenoids as yellow plumage colorants, and that the ability to metabolically modify dietary carotenoids into more complex pigments arose secondarily once finches began to use modified carotenoids to create red plumage. Following the evolutionary “innovation” that enabled modified red carotenoid pigments to be deposited as plumage colorants, many finch species subsequently modified carotenoid biochemical pathways to create yellow plumage. However, no reversions to dietary carotenoids were observed. The finding that ornaments and their underlying mechanisms may be operating under different selection regimes—where ornamental trait colors undergo frequent reversions (e.g., between red and yellow plumage) while carotenoid metabolization mechanisms are more conserved—supports a growing empirical framework suggesting different evolutionary patterns for ornaments and the mechanistic innovations that facilitate their diversification

GPS and Galileo Triple-Carrier Ionosphere-Free Combinations for Improved Convergence in Precise Point Positioning

In recent years, global navigation satellite system (GNSS) precise point positioning (PPP) has become a standard positioning technique for many applications with typically favourable open sky conditions, e.g. precision agriculture. Unfortunately, the long convergence (and reconvergence) time of PPP often significantly limits its use in difficult and restricted signal environments typically associated with urban areas. The modernisation of GNSS will positively affect and improve the convergence time of the PPP solutions, thanks to the higher number of satellites in view that broadcast multifrequency measurements. The number and geometry of the available satellites is a key factor that impacts on the convergence time in PPP, while triple-frequency observables have been shown to greatly benefit the fixing of the carrier phase integer ambiguities. On the other hand, many studies have shown that triple-frequency combinations do not usefully contribute to a reduction of the convergence time of float PPP solutions.This paper proposes novel GPS and Galileo triple-carrier ionosphere-free combinations that aim to enhance the observability of the narrow-lane ambiguities. Tests based on simulated data have shown that these combinations can reduce the convergence time of the float PPP solution by a factor of up to 2·38 with respect to the two-frequency combinations. This approach becomes effective only after the extra wide-lane and wide-lane ambiguities have been fixed. For this reason, a new fixing method based on low-noise pseudo-range combinations corrected by the smoothed ionosphere correction is presented. By exploiting this algorithm, no more than a few minutes are required to fix the WL ambiguities for Galileo, even in cases of severe multipath environments

Age-dependent relationships between multiple sexual pigments and condition in males and females

The reliability of sexual signaling may change across age classes due to shifts in resource allocation patterns. Two contrasting hypotheses exist regarding how the condition dependence of ornaments may shift with age, and both have received empirical support. On one hand, ornaments may more reliably reflect condition and quality in older individuals, because younger individuals of high quality invest in survival over signaling effort. On the other hand, the condition dependence of ornaments may decline with age, if older individuals in poor condition terminally invest in ornaments, or if resource constraints decline with age. Further, the expression and condition dependence of different ornaments may shift with age in unique ways, such that multifaceted sexual displays maintain reliable signaling across age classes. In yellow warblers (Setophaga petechia) of both sexes, we assessed how relationships between carotenoid-and phaeomelanin-based sexual pigmentation, prenesting body reserves, and condition at molt (reflected by growth bars and feather quality) vary across age classes. Melanin coverage correlated with condition at molt across age classes in males and showed high repeatability in both sexes. In contrast, carotenoid saturation increased longitudinally with age in males and correlated with condition at molt in different age classes in the 2 sexes. Specifically, carotenoid saturation correlated positively with condition at molt in younger, but not older males, whereas in females, the situation was reversed, with a positive correlation present only in older females. Results suggest that age-dependent signaling may promote maintenance of multifaceted sexual displays and that agedependent signaling dynamics depend on sex. © The Author 2013. Published by Oxford University Press on behalf of the International Society for Behavioral Ecology. All rights reserved

Supplemental Information 3: Dataset including repeated measures for the carotenoid-supplement experiment. The dataset excludes birds receiving diquat (see Methods). Description of variables inserted as comments on variable names.

Colorful ornaments have been the focus of sexual selection studies since the work of Darwin. Yellow to red coloration is often produced by carotenoid pigments. Different hypotheses have been formulated to explain the evolution of these traits as signals of individual quality. Many of these hypotheses involve the existence of a signal production cost. The carotenoids necessary for signaling can only be obtained from food. In this line, carotenoid-based signals could reveal an individual's capacity to find sufficient dietary pigments. However, the ingested carotenoids are often yellow and became transformed by the organism to produce pigments of more intense color (red ketocarotenoids). Biotransformation should involve oxidation reactions, although the exact mechanism is poorly known. We tested the hypothesis that carotenoid biotransformation could be costly because a certain level of oxidative stress is required to correctly perform the conversion. The carotenoid-based signals could thus reveal the efficiency of the owner in successfully managing this challenge. In a bird with ketocarotenoid-based ornaments (the red-legged partridge Alectoris rufa), the availability of different carotenoids in the diet (i.e. astaxanthin, zeaxanthin and lutein) and oxidative stress were manipulated. The carotenoid composition was analyzed and quantified in the ornaments, blood, liver and fat. A number of oxidative stress biomarkers were also measured in the same tissues. First, we found that color and pigment levels in the ornaments depended on food levels of those carotenoids used as substrates in biotransformation. Second, we found that birds exposed to mild levels of a free radical generator (diquat) developed redder bills and deposited higher amounts of ketocarotenoids (astaxanthin) in ornaments. Moreover, the same diquat-exposed birds also showed a weaker resistance to hemolysis when their erythrocytes were exposed to free radicals, with females also enduring higher oxidative damage in plasma lipids. Thus, higher color production would be linked to higher oxidative stress, supporting the biotransformation hypothesis. The recent discovery of an avian oxygenase enzyme involved in converting yellow to red carotenoids may support our results. Nonetheless, the effect could also depend on the abundance of specific substrate carotenoids in the diet. Birds fed with proportionally higher levels of zeaxanthin showed the reddest ornaments with the highest astaxanthin concentrations. Moreover, these birds tended to show the strongest diquat-mediated effect. Therefore, in the evolution of carotenoid-based sexual signals, a biotransformation cost derived from maintaining a well-adjusted redox machinery could coexist with a cost linked to carotenoid acquisition and allocation (i.e. a resource allocation trade-off).Esther García-de Blas was supported by a predoctoral grant (JAE-PRE) from the Consejo Superior de Investigaciones Científicas (CSIC) co-financed by Fondo Social Europeo (EU). This study was funded by Consejería de Educación y Ciencia, Junta de Comunidades de Castilla la Mancha (project ref.: PII1I09-0271-5037) and Ministerio de Economía y Competitividad (CGL2009-10883-C02-02 and CGL2015-69338-C2-2-P) from the Spanish Government.Peer Reviewe