bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differential effects of conspecific and heterospecific density on the development of Aedes aegypti and Aedes albopictus larvae
Authors: Paton Robert S , Heath Katherine , Wilson Anthony J , Bonsall Michael B 
Published: August 2018

AbstractBetween-species competition shapes the distribution and abundance of populations. Aedes aegypti and Ae. albopictus are vectors of pathogens such as dengue and are known to compete at the larval stage.The outcome of this inter-species competition has been found to be context dependent, with the strength and direction changing with resource availability and type. We were motivated by this uncertainty, and aimed to elucidate the magnitude and mechanism of competition.We manipulated the larval density of mixed and single species cohorts of larvae, measuring the effects on survivorship and development time. Unlike other related studies, we adjusted the feeding regime so that the per-capita resource availability was kept constant across all density treatments, at a level sufficient for successful development. This ensured that each larvae at least had the opportunity to gain the requisite resources for pupation.Our analysis found that Ae. aegypti suffered notably less mortality due to intra- and interspecific competition. For both species, intra- and interspecific competition led to the survival of faster developing individuals, with the exception that slower developing Ae. albopictus larvae survived when exposed a combination of both high con- and heterospecific densities.These results show that the competition between Ae. aegypti and Ae. albopictus can still occur even when resources are theoretically adequate for development. This suggests that larvae can alter resource seeking and consumption parameters when exposed to high densities of conspecifics and heterospecifics, leading to contest competition. Evidence for resource-independent mechanisms of competition such as crowding are also found, as is evidence for the importance of demographic stochasticity in population processes.
TreeN93: a non-parametric distance-based method for inferring viral transmission clusters
Authors: Moshiri Niema 
Published: August 2018

AbstractSummaryHighly-used methods for identifying transmission clusters of rapidly-evolving pathogens from molecular data require a user-determined distance threshold. The choice of threshold is often motivated by epidemiological information known a priori, which may be unfeasible for epidemics without rich epidemiological information. TreeN93 is a fully non-parametric distance-based method for transmission cluster identification that scales polynomially.Availability and implementationTreeN93 is implemented in Python 3 and is freely available at https://github.com/niemasd/TreeN93/.Contactniemamoshiri@gmail.com
Neural competitive queuing of ordinal structure underlies skilled sequential action
Authors: Kornysheva Katja , Bush Dan , S Meyer Sophie , Sadnicka Anna , Barnes Gareth , Burgess Neil 
Published: August 2018

AbstractThe fluent retrieval and production of movement sequences is essential for a variety of daily activities such as speech, tool-use, musical and athletic performance, but the neural mechanisms underlying sequence planning remain elusive. Here, participants learned sequences of finger presses with different timings and different finger orders, and reproduced them in a magneto-encephalography (MEG) scanner. We classified the MEG patterns immediately preceding each press in the sequence, and examined their dynamics over the production of the whole sequence. Our results confirm a role for the ‘competitive queuing’ of upcoming action representations in the production of learned motor sequences, extending previous computational and non-human primate recording studies to non-invasive measures in humans. In addition, we show that competitive queuing does not simply reflect specific motor actions, but representations of higher-level sequential order that generalise across different motor sequences. Finally, we show that the quality of competitive queuing predicts participants’ production accuracy, and originates from parahippocampal and cerebellar sources. These results suggest that the brain learns and produces multiple behavioural sequences by flexibly combining representations of specific actions with more abstract, parallel representations of sequential structure.
Encircling the regions of the pharmacogenomic landscape that determine drug response
Authors: Fernández-Torras Adrià , Duran-Frigola Miquel , Aloy Patrick 
Published: August 2018

AbstractBackgroundThe integration of large-scale drug sensitivity screens and genome-wide experiments is changing the field of pharmacogenomics, revealing molecular determinants of drug response without the need for previous knowledge about drug action. In particular, transcriptional signatures of drug sensitivity may guide drug repositioning, prioritize drug combinations and point to new therapeutic biomarkers. However, the inherent complexity of transcriptional signatures, with thousands of differentially expressed genes, makes them hard to interpret, thus giving poor mechanistic insights and hampering translation to clinics.MethodsTo simplify drug signatures, we have developed a network-based methodology to identify functionally coherent gene modules. Our strategy starts with the calculation of drug-gene correlations and is followed by a pathway-oriented filtering and a network-diffusion analysis across the interactome.ResultsWe apply our approach to 189 drugs tested in 671 cancer cell lines and observe a connection between gene expression levels of the modules and mechanisms of action of the drugs. Further, we characterize multiple aspects of the modules, including their functional categories, tissue-specificity and prevalence in clinics. Finally, we prove the predictive capability of the modules and demonstrate how they can be used as gene sets in conventional enrichment analyses.ConclusionsNetwork biology strategies like module detection are able to digest the outcome of large-scale pharmacogenomic initiatives, thereby contributing to their interpretability and improving the characterization of the drugs screened.
A macrophage-based screen identifies antibacterial compounds selective for intracellularSalmonellaTyphimurium
Authors: Ellis Michael J. , Tsai Caressa N. , Johnson Jarrod W. , French Shawn , Elhenawy Wael , Porwollik Steffen , Andrews-Polymenis Helene , McClelland Michael , Magolan Jakob , Coombes Brian K. , Brown Eric D. 
Published: August 2018

AbstractSalmonellaTyphimurium (S. Tm) evades the innate immune response by residing within host phagocytes. To identify inhibitors of intracellularS. Tm growth, we performed parallel chemical screens againstS. Tm growing in macrophage-mimicking media and within macrophages. These screens identified novel antibacterials, and revealed that antibiotics with limited Gram-negative coverage are active against intracellularS. Tm. Screening of aS. Tm deletion library in the presence of one compound, metergoline, revealed that outer membrane perturbation enhanced activityin vitro. Combined with our observation of atypical cell surface characteristics of intracellularS. Tm, our work indicates that the bacterial outer membrane is permeabilized within macrophages. We show that metergoline targets the bacterial cytoplasmic membrane, and prolongs animal survival during a systemicS. Tm infection. This work highlights the predictive nature of intracellular screens forin vivoefficacy, and uncovers new aspects of bacterial physiology of intracellularS. Tm.
The effect of transitioning to renewable energy consumption on the Nigerian oil and gas exports
Authors: Waziri Bukar Zanna , Hassan Aminu , Kouhy Reza 
Published: July 2018

PurposeNet energy importing countries (NEICs) pursue strategic policies to reduce the consumption of energy from conventional sources and increase that of renewable energy to attain energy security and sustainable development. However, net energy exporting countries (NEECs) rely substantially on the proceeds realised from oil and gas exports to mainly NEICs to finance government activities. This paper aims to investigate the effect of increased consumption of renewable energy in developed NEICs on the Nigeria’s oil and gas exports.Design/methodology/approachThe study was undertaken by analysing macro-economic annual time-series data set (1980-2014) using autoregressive distributed lag (ARDL) bounds testing approach.FindingsBoth the short-run and the long-run results of the ARDL modelling reveal that renewable energy consumption in developed NEICs is affecting Nigeria’s oil and gas exports negatively, thereby causing significant decrease in the amounts of revenue being generated therefrom.Research limitations/implicationsLike most empirical studies, the conduct of this research has encountered some challenges. Thus, the use of rather small sample in terms of period covered (1980-2014), annual frequency of data and focus on one NEEC (Nigeria) are the key limitations of this paper. While the first two challenges were dealt with by using ARDL, future research can focus on other NEECs to extend the study.Practical implicationsThe findings have several policy implications, including the need for Nigeria to focus on developing internal market trajectories to increase domestic utilisation of its conventional energy rather than depending on external markets. The results also suggest the need for public policymakers to develop a strategic plan that will effectively address the external economic threat arising from the influence of global energy transition.Originality/valueTo the best of the authors’ knowledge, this paper represents the first effort to empirically examine the effect of renewable energy consumption by developed NEICs on the Nigeria’s oil and gas exports. The paper contributes to the literature by providing insight into and documenting evidence that the world is taking transitioning to cleaner energy sources very seriously.
Immigration detention and liberal democracies
Authors: Ikegwuruka Cosmas 
Published: July 2018

Purpose
Liberal democratic states have involved the use of private companies for purposes of detention and the debate is whether such involvement is only for immigration control or whether they are primarily for macro-economic benefits. This paper aims to present the argument that a State wishing to detain migrants must do so within the purview of immigration control and in conformity to international human rights standards rather than other latent reasons such as macro-economic benefits. The exponential growths of immigration detention over the years, this paper argues, smack of latent reasons with unarguably macro-economic benefits accruing to these States.

Design/methodology/approach
The methodology is doctrinal research focusing on immigration detention and privatization. Doctrinal research is library-based and reliance will be placed on primary and secondary materials such as legislations, case laws, soft laws on the one hand and textbooks, journals, articles, legal encyclopedia, databases and many valuable websites on the other hand.

Findings
Findings have been made of similarities in State practice between the UK, the USA and Australia and conclude that the trend is worrying given that privatization of the detention estate lends credence to the fact that growing international prison industry influences prison and detention policies.

Research limitations/implications
These have portent implications for the violations of the rights of detainees and weaken the protection of rights under international human rights law.

Originality/value
The originality of this paper lies in its ability to unravel the legitimacy of immigration detention in the face of privatization and macro-economic benefits accruing to States, thereby querying the availability of the rights of migrants within the remit of State practice.
Trends in learning analytics practices: a review of higher education institutions
Authors: Wong Billy Tak-Ming , Li Kam Cheong , Choi Samuel Ping-Man 
Published: July 2018

Purpose
This paper aims to review and identify the major patterns and trends in learning analytics practices in higher education institutions. The review covers the characteristics of the institutions, as well as the characteristics and outcomes of the learning analytics practices.

Design/methodology/approach
This research collected literature published in 2011-2016 which reported learning analytics practices from Scopus and Google Scholar, covering a total of 47 institutions, and categorised the information about the relevant institutions and practices.

Findings
The results show that most of the institutions were public ones in the USA and the UK of various sizes and offering different levels of study. The learning analytics practices were mainly institution-wide, apart from a small number focusing on selected courses. The purposes of the practices were mainly to enhance the effectiveness of learning support and administration, followed by facilitating students’ learning progress. The most common types of data collected for the practices were students’ academic behaviours and their background information. Positive outcomes were reported for a majority of the practices, and the most frequent ones being an increase in cost-effectiveness and understanding of students’ learning behaviours. Other outcomes included the improvement of student retention, timely feedback and intervention, support for informed decision-making and the provision of personalised assistance to students.

Originality/value
The results provide an overview of the use of learning analytics in the higher education sector. They also reveal the trends in learning analytics practices, as well as future research directions.
Corporate diversification
Authors: Smith Garrett C.C. , Coy Jeffrey M. 
Published: August 2018

PurposeThe purpose of this study is to compare two theories that relate the proportion of diversified firms in the economy and the implied discount for diversified firms: the first is a real-options model predicting a positive relationship between the discount and management’s choice to operate a diversified firm; the second is based on catering theory, in which a negative relationship is predicted, as management is attentive to investor preference concerning diversified firms.Design/methodology/approachThis study proposes a new aggregate measure of the diversification discount. The authors’ measure allows for decomposition of the discount into firm-level mispricing, industry-level mispricing and long-run fundamental value components.FindingsResults support a catering theory of diversification. The discount appears to be the result of firm-level mispricing. Thus, providing an explanation for why, in light of the observed discount, a large number of diversified firms persist.Originality/valueTo the authors’ knowledge, this is the first study to provide evidence that firm-level mispricing may drive the observed diversification discount.
Water retention effects on elastic properties of Opalinus shale
Authors: Yurikov Alexey , Lebedev Maxim , Pervukhina Marina , Gurevich Boris 
Published: July 2018

ABSTRACTShales play an important role in many engineering applications such as nuclear waste, CO2 storage and oil or gas production. Shales are often utilized as an impermeable seal or an unconventional reservoir. For both situations, shales are often studied using seismic waves. Elastic properties of shales strongly depend on their hydration, which can lead to substantial structural changes. Thus, in order to explore shaly formations with seismic methods, it is necessary to understand the dependency of shale elastic properties on variations in hydration. In this work, we investigate structural changes in Opalinus shale at different hydration states using laboratory measurements and X‐ray micro‐computed tomography. We show that the shale swells with hydration and shrinks with drying with no visible damage. The pore space of the shale deforms, exhibiting a reduction in the total porosity with drying and an increase in the total porosity with hydration. We study the elastic properties of the shale at different hydration states using ultrasonic velocities measurements. The elastic moduli of the shale show substantial changes with variations in hydration, which cannot be explained with a single driving mechanism. We suggest that changes of the elastic moduli with variations in hydration are driven by multiple competing factors: (1) variations in total porosity, (2) substitution of pore‐filling fluid, (3) change in stiffness of contacts between clay particles and (4) chemical hardening/softening of clay particles. We qualitatively and quantitatively analyse and discuss the influence of each of these factors on the elastic moduli. We conclude that depending on the microstructure and composition of a particular shale, some of the factors dominate over the others, resulting in different dependencies of the elastic moduli on hydration.
Why are demographic Allee effects so rarely seen in social animals?
Authors: Lerch Brian A. , Nolting Ben C. , Abbott Karen C. 
Published: July 2018

Abstract

Allee effects in group‐living species are common, but little is known about the way in which Allee effects at the group‐level scale up to influence population dynamics. Most notably, it remains unclear whether component Allee effects within groups (where some component of fitness in small groups decreases with decreasing group size) will translate into a population‐level demographic Allee effect (where per capita fitness in small populations decreases with decreasing overall population size).

The African wild dog (Lycaon pictus) is an obligate cooperative breeder that lives in packs and has a multitude of group‐level component Allee effects. With the African wild dog as a case study, we use models to determine the effect that group structure has on the population dynamics of social animals and, specifically, whether Allee effects operating at the group level lead to a demographic Allee effect at the population level.

We developed a suite of models to analyse the population dynamics of group‐living species, as well as comparable “packless” models lacking group structure. By comparing these models, we can identify how Allee effects within groups influence population‐level dynamics.

Our results show that group structure buffers populations against a demographic Allee effect, because mechanisms affecting birth and mortality are more strongly influenced by group size than population size. We find that interactions between groups are vital in determining the relationship between density dependence within groups and density dependence at the population level.

As sufficiently large groups provide protection against positive density dependence, even at low overall population sizes, our results have conservation implications for group‐living species, as they suggest group size is a necessary population feature to consider in efforts to manage population size. Furthermore, we provide novel insight regarding the role that dispersal and pack size variation play in the buffering nature of social structure in groups subject to Allee effects.
No role for xylem embolism or carbohydrate shortage in temperate trees during the severe 2015 drought
Authors: Dietrich Lars , Delzon Sylvain , Hoch Guenter , Kahmen Ansgar 
Published: July 2018

AbstractTemperate forests are predicted to experience an increased frequency and intensity of climate change‐induced summer droughts and heat waves in the near future. Yet, while previous studies clearly showed a high drought sensitivity of different temperate tree species, the vulnerability of the physiological integrity of these trees remains unclear.Here, we assessed the sensitivity of six temperate tree species to severe water limitation during three consecutive growing seasons, including the exceptional 2015 central European summer drought and heat wave. Specifically, we assessed stem increment growth, sap flow, water potentials, hydraulic vulnerability, and nonstructural carbohydrate contents in leaves and branches to determine how mature temperate trees responded to this exceptional weather event and how the observed responses relate to variation in xylem embolism and carbohydrate economy.We found that the trees' predawn water potentials reached their minimum values during the 2015 summer drought and most species reduced their sap flow by up to 80%. Also, increment growth was strongly impaired with the onset of the drought in all species. Despite the strong responses in the trees' growth and water relations, all species exhibited minimum midday shoot water potentials well away from values associated with severe embolism (P50). In addition, we detected no distinct decrease in nonstructural carbohydrate contents in leaves, bark, and stems throughout the drought event.Synthesis. This study shows that mature individuals of six common central European forest tree species strongly reacted to a severe summer drought by reducing their water consumption and stopping growth. We found, however, no indications for xylem embolism or carbohydrate depletion in these trees. This suggests, that xylem embolism formation and carbohydrate reserve depletion are not routine in temperate trees during seasonal strong drought and reveals a low vulnerability of the physiological integrity of temperate trees during drought events as we describe here.
Understorey succession after burial by tephra from Mount St. Helens
Authors: Fischer Dylan G. , Antos Joseph A. , Biswas Abir , Zobel Donald B. 
Published: July 2018

Abstract

Successional change following disturbance is a fundamental ecological process that remains central to understanding patterns in plant ecology. Although succession has been studied for well over a century, understanding of the patterns and processes of change is still inadequate, partly because of the dearth of long‐term studies.

Here, we use, as a model system, a volcanic disturbance that is widespread and of global relevance. We examine succession in old‐growth conifer forest understories following burial by tephra (aerially transported volcanic ejecta) in the 1980 eruption of Mount St. Helens. Using four sites with different initial conditions and amounts of disturbance (tephra burial), we sampled plant communities at years 1, 20, and 36 since the eruption using permanent plots representing two treatments: undisturbed tephra and control plots from which tephra was experimentally removed. By using this long‐term data, we were able to gauge change through time and differences between tephra‐disturbed and control plots.

In tephra‐impacted plots, cover reached preeruption levels by year 36 except for bryophytes at three sites and shrubs at one site. Cover in control plots also increased significantly for all growth forms except bryophytes, remaining above that on tephra plots at the same site in most situations. Sites generally increased in species richness first, and then gradually increased in evenness and Shannon’s diversity; after 36 years, differences between control and tephra‐impacted plots remained at only one site. Community composition was stable in one site and shifted gradually through time at the two other sites, and differences between plot types persisted at one site. Communities change over 36 years could relate to various endogenic and abiotic factors.

Synthesis. These data suggest that, while recovery to the predisturbance status occurs in some cases, recovery is site‐specific. Understorey communities can be dynamic, even in old‐growth forests, and may still be responding to disturbance over three decades later. Long‐term experimental studies are key to understanding succession patterns and generalizations about the importance of initial conditions, disturbance intensity, and the complexity of interactions that determine vegetation change.