bluuebunny/crossref_metadata_2025 huggingface dataset:
Sex differences in fear regulation and reward seeking behaviors in a fear-safety-reward discrimination task
Authors: Greiner Eliza M. , Norris Makenzie R. , Müller Iris , Ng Ka H. , Sangha Susan
Published: August 2018

Reward availability and the potential for danger or safety potently regulates emotion. Despite women being more likely than men to develop emotion dysregulation disorders, there are comparatively few studies investigating fear, safety and reward regulation in females. Here, we show that female Long Evans rats do not suppress conditioned freezing in the presence of a safety cue, nor do they extinguish their freezing response, whereas males do both. Females were also more reward responsive during the reward cue until the first footshock exposure, at which point there were no sex differences in reward seeking to the reward cue. Darting analyses indicate females might be able to regulate this behavior in response to the safety cue, suggesting they might be able to discriminate between fear and safety cues but do not demonstrate this with conditioned suppression of the freezing behavior. However, levels of darting in this study were too low to make any clear conclusions. In summary, females showed a significantly different behavioral profile than males in a task that tests the ability to discriminate among fear, safety and reward cues. This paradigm offers a great opportunity to test for mechanisms that are generating these behavioral sex differences in learned safety and reward seeking.
Concurrent neural representations of the current and forthcoming movement plans in the frontal eye field during a saccade sequence
Authors: Basu Debaleena , Murthy Aditya
Published: August 2018

We use sequences of saccadic eye movements to continually explore our visual environments. Previous studies have established that saccades in a sequence may be programmed in parallel by the oculomotor system. In this study, we tested the neural correlates of parallel programming of saccade sequences in the frontal eye field (FEF), using single-unit electrophysiological recordings from macaques performing a double-step saccade task. Neurons in the FEF range from visual neurons instantiating target selection, to movement neurons which prepare a saccadic response towards the selected target. The question of whether the FEF movement neurons undertake concurrent processing of multiple goals or saccade plans is yet unresolved. We show that when a peripheral target is foveated by a sequence of two saccades, FEF movement activity for the second saccade can be initiated whilst the first is still underway. Moreover, the onset of the movement activity varied parametrically with the behaviorally measured time available for parallel programming. Finally, the concurrent activity was specific for the final remapped motor vector connecting the first and the second targets and not the goal of the second saccade. In contrast, the upstream FEF visual-related neurons showed concurrent activity related to the goal of the second saccade, but not the remapped vector connecting the first and the second targets. Taken together, the results indicate that movement neurons, although located terminally in the FEF visual-motor spectrum, can accomplish concurrent processing of multiple saccade plans, leading to rapid execution of saccade sequences.
NMDA Receptor Dysregulation by Defective Depalmitoylation in the Infantile Neuronal Ceroid Lipofuscinosis Mouse Model
Authors: Koster Kevin P , Francesconi Walter , Berton Fulvia , Alahmadi Sami , Srinivas Roshan , Yoshii Akira
Published: August 2018

Protein palmitoylation and depalmitoylation alter protein function. This post-translational modification is critical for synaptic transmission and plasticity. Mutation of the depalmitoylating enzyme palmitoyl-protein thioesterase 1 (PPT1) causes infantile neuronal ceroid lipofuscinosis (CLN1), a pediatric neurodegenerative disease. However, the role of protein depalmitoylation in synaptic maturation is unknown. Therefore, we studied synapse development inPpt1-/-mouse visual cortex. We demonstrate the stagnation of the developmental N-methyl-D-aspartate receptor (NMDAR) subunit switch from GluN2B to GluN2A inPpt1-/-mice. Correspondingly, GluN2A-mediated synaptic currents are diminished andPpt1-/-dendritic spines maintain immature morphologyin vivo. Further, GluN2B is hyperpalmitoylated inPpt1-/-neurons and associated with extrasynaptic, diffuse calcium influxes and enhanced vulnerability to NMDA-induced excitotoxicity. Remarkably,Ppt1-/-neurons treated with palmitoylation inhibitors demonstrate normalized levels of palmitoylated GluN2B and Fyn kinase, reversing susceptibility to excitotoxic insult. Thus, depalmitoylation of GluN2B by PPT1 plays a critical role in postsynapse maturation and pathophysiology of neurodegenerative disease.
Maize EHD1 is Required for Kernel Development and Vegetative Growth through Regulating Auxin Homeostasis
Authors: Wang Yafei , Liu Wenwen , Wang Hongqiu , Du Qingguo , Fu Zhiyuan , Li Wen-Xue , Tang Jihua
Published: August 2018

The roles of EHDs in clathrin-mediated endocytosis (CME) in plants are poorly understood. Here, we isolated a maize mutant, designated asehd1, which showed defects in kernel development and vegetative growth. Positional cloning and transgenic analysis revealed thatehd1encodes an EHD protein. Internalization of the endocytic tracer FM4-64 was significantly reduced inehd1mutant andZmEHD1knock-out mutants. We further demonstrated that ZmEHD1 and ZmAP2 σ subunit physically interact in the plasma membranes. Cellular IAA levels were significantly lower inehd1mutant than in wild-type maize. Auxin distribution and ZmPIN1a-YFP localization were altered inehd1mutant. Exogenous application of 1-NAA but not GA3 rescued the seed germination and seedling emergency phenotypic defects ofehd1mutants. Taken together, these results indicate that ZmEHD1 regulates auxin homeostasis by mediating CME through its interaction with the ZmAP2 σ subunit, which is crucial for kernel development and vegetative growth of maize.
Hippo Pathway Deregulation Drives Tissue Stiffness and Cancer Stem-like Cells in Lung Adenocarcinoma
Authors: Pankova Daniela , Jiang Yanyan , Vendrell Iolanda , Buzzelli Jon N. , Ryan Anderson , Brown Cameron , O’Neill Eric
Published: August 2018

Lung cancer remains the leading cause of cancer-related death due to poor treatment responses arising from tumor heterogeneity and epigenetic aberrations. Here we show that adverse prognosis associated with epigenetically silenced tumour suppressor RASSF1A is a consequence of increased extracellular matrix, tumour stiffness and metastatic disseminationin vivoandin vitro. We find that lung cancer cells with methylated RASSF1A display constitutive nuclear YAP1 and expression of prolyl4hydroxylase2 (P4HA2) into extracellular matrix that correlates with increases collagen deposition. Furthermore, we identify an epigenetic axis in tumour cells where elevated ECM impedes the intrinsic suppression of WNT signaling (via TPBG/5T4) triggering b-catenin-YAP1 activation and thus results in a cancer stem-like programming. As key drivers, we identified RASSF1A and P4HA2 mediating the ECM-dependent stemness and metastatic disseminationin vivo. Re-expression of RASSF1A or inhibition of P4HA2 activity reverse these effects and increase levels of lung differentiation markers (TTF-1, Mucin5B)in vivoandin vitro. Our study identifies an epigenetic program to cancer stemness and metastatic progression of lung adenocarcinoma and P4HA2 as potential target for uncoupling ECM signals towards cancer stemness.
Predicting provenance of forensic soil samples: soil DNA predicts habitat and environmental properties
Authors: Fløjgaard Camilla , Frøslev Tobias Guldberg , Brunbjerg Ane Kirstine , Bruun Hans Henrik , Moeslund Jesper , Hansen Anders Johannes , Ejrnæs Rasmus
Published: August 2018

Environmental DNA is increasingly applied in ecological studies, including forensic ecology where eDNA from soil can be used to pair samples or reveal sample provenance. We collected soil eDNA samples as part of a large national biodiversity research project across 130 sites in Denmark. We investigated the potential for soil eDNA in predicting provenance in terms of environmental conditions, habitat characteristics and geographic regions. We used linear regression for predicting environmental gradients of light, moisture, soil pH and nutrients (represented by Ellenberg Indicator Values, EIVs) and quadratic discriminant analysis (QDA) to predict habitat class and geographic region. We found high predictive power for environmental gradients (R2 > 0.73). The discriminatory power of QDA in predicting habitat characteristics varied from high accuracy in predicting certain forest types, less accurate prediction of heathland and poor accuracy for geographic region. We demonstrate the application of provenance prediction in forensic science by evaluating and discussing two mock crime scenes. Here, we supplement with plant species lists from annotated sequences. Where predictions of environmental gradients and habitat classes give an overall accurate description of a crime scene, care should be taken when interpreting annotated sequences, e.g. due to erroneous assignments in GenBank. The outlined approach clearly demonstrates that basic ecological information that can be extracted from soil eDNA, contributing to the range of potential applications of eDNA in forensic ecology.
Strain typing and characterization of virulence genes in clinicalStaphylococcus aureusisolates from Kenya
Authors: Kyany’a Cecilia , Nyasinga Justin , Matano Daniel , Oundo Valerie , Wacira Simon , Sang Willie , Musila Lillian
Published: August 2018

Staphylococcusaureusstrain typing is an important surveillance tool as particular strains have been associated with virulence and community and hospital acquired MRSA outbreaks globally. This study sought to determine the circulating strain types ofS.aureusin Kenya and establish the virulence genes among the strains. ClinicalS.aureusisolates from 3 hospitals in Kenya were sequenced on the Illumina Miseq and genomes assembled and annotated on PATRIC. Results demonstrated great diversity among the isolates with identification of 6 distinct CC (8,22,15,80,121,152), 8 ST types (8, 15, 22,80,121,152,241, 1633) and 8 spa types (t005, t037, t064, t084, t233, t2029, t272,t355). Novel STs (4705, 4707) and a novel spa type (t17826) were identified. The most prominent clonal complex was CC 152 comprised of only MSSA. A majority of MRSA isolates (3/4) typed to ST 241, CC8. One MRSA isolate typed to a novel ST 4705. All isolates were screened for a panel of 56 known virulence genes (19 adhesins, 9 hemolysins, 5 immune evasion proteins, 6 exo-enzymes and 19 toxins). 9 toxin genes were detected among the isolates with CC8 isolates having the highest numbers of toxin genes. An MSSA isolate (CC8) from a severe burn infection had the highest number of toxin genes (5). All MRSA isolates (CC8) had only 2 toxins, SEK and SEQ, whereas a majority of the MSSA isolates either had 0 or ≥2 toxins. SEK+SEQ and TSST-1+SEB+SEL toxin combinations were observed among patients whose disease resulted in hospitalization, an indicator of severe infections. This study confirms the highly heterogeneousS.aureuspopulation in Kenya. MSSA appear to have the potential of accumulating more toxin genes than MRSA. This co-occurrence of major toxin genes, some associated with MRSA, highlights the potential risks of outbreaks of highly virulent MRSA infections which would pose treatment challenges.
Shear stress mediates metabolism and growth in electroactive biofilms
Authors: Jones A-Andrew D , Buie Cullen R
Published: August 2018

Electroactive bacteria such asGeobacter sulfurreducensandShewanella onedensisproduce electrical current during their respiration; this has been exploited in bioelectrochemical systems. These bacteria form thicker biofilms and stay more active than soluble-respiring bacteria biofilms because their electron acceptor is always accessible. In bioelectrochemical systems such as microbial fuel cells, corrosion-resistant metals uptake current from the bacteria, producing power. While beneficial for engineering applications, collecting current using corrosion resistant metals induces pH stress in the biofilm, unlike the naturally occurring process where a reduced metal combines with protons released during respiration. To reduce pH stress, some bioelectrochemical systems use forced convection to enhance mass transport of both nutrients and byproducts; however, biofilms’ small pore size limits convective transport, thus, reducing pH stress in these systems remains a challenge. Understanding how convection is necessary but not sufficient for maintaining biofilm health requires decoupling mass transport from momentum transport (i.e. fluidic shear stress). In this study we use a rotating disc electrode to emulate a practical bioelectrochemical system, while decoupling mass transport from shear stress. This is the first study to isolate the metabolic and structural changes in electroactive biofilms due to shear stress. We find that increased shear stress reduces biofilm development time while increasing its metabolic rate. Furthermore, we find biofilm health is negatively affected by higher metabolic rates over long-term growth due to the biofilm’s memory of the fluid flow conditions during the initial biofilm development phases. These results not only provide guidelines for improving performance of bioelectrochemical systems, but also reveal features of biofilm behavior. Results of this study suggest that optimized reactors may initiate operation at high shear to decrease development time before decreasing shear for steady-state operation. Furthermore, this biofilm memory discovered will help explain the presence of channels within biofilms observed in other studies.
Estimating Individual Contributions to Complex DNA SNP Mixtures
Authors: Ricke Darrell O. , Fremont-Smith Philip , Watkins James , Boettcher Tara , Schwoebel Eric
Published: August 2018

Mixture analysis and deconvolution methods can identify both known and unknown individuals contributing to DNA mixtures. These methods may not identify all DNA contributors with the remaining fraction of the mixture being contributed by one or more unknown individuals. The proportion of DNA contributed by individuals to a forensic sample can be estimated using their quantified mixture alleles. For short tandem repeats (STRs), methods to estimate individual contribution concentrations compare capillary electrophoresis peak heights and or peak areas within a mixture. For single nucleotide polymorphisms (SNPs), the major:minor allele ratios or counts, unique to each contributor, can be compared to estimate contributor proportion within the mixture. This article introduces three approaches (mean, median, and slope methods) for estimating individual DNA contributions to forensic mixtures for high throughput sequencing (HTS)/massively parallel sequencing (MPS) SNP panels.
Managing embodied carbon in buildings: a Pareto approach
Authors: Victoria Michele Florencia , Perera Srinath
Published: August 2018

Purpose

The purpose of this paper is to identify the carbon intensive building elements or “carbon hotspots” of office buildings in order to maximise the carbon reduction potential during design stages.

Design/methodology/approach

Embodied carbon (EC) estimates of 28 office buildings in the UK were obtained and carbon hotspots of the sample (in accordance with the new rules of measurement (NRM) element classification) were identified using the 80:20 Pareto principle.

Findings

Frame, substructure, external walls, services and upper floors were identified as carbon hotspots of the selected sample. However, findings do not support the 80:20 ratio in this case but propose a ratio of 80:36. Stairs, internal walls and partitions, internal doors, wall finishes, ceiling finishes and fittings and furnishings were identified as carbon insignificant elements that have a lower EC reduction potential compared to the rest.

Research limitations/implications

The findings are applicable to office buildings in the UK but the methodology is adaptable to different types of buildings in other countries.

Originality/value

Findings unveil carbon intensive and carbon insignificant building elements of typical office buildings in the UK. This informs designers of the elements that could yield the highest potential EC savings via effective design choices. In addition, a logical design timeline is proposed for building elements based on their element hotspot category and design sequence to assist design decision making.
Participatory communication on internal social media – a dream or reality?
Authors: Madsen Vibeke Thøis
Published: August 2018

Purpose

The purpose of this paper is to explore whether internal social media (ISM) introduces a new kind of participatory communication within organizations that is capable of influencing and moving the organization.

Design/methodology/approach

The paper is based on two exploratory studies: a multiple case study in ten Danish organizations, and a single case study in a Danish bank.

Findings

The paper finds that different types of communication on ISM develop in different types of organizations. Participatory communication capable of changing the organization only develops when coworkers perceive that they have a license to critique. The paper, therefore, proposes to distinguish between three different types of communication arenas created by ISM: a quiet arena, a knowledge-sharing arena and a participatory communication arena.

Research limitations/implications

The research is exploratory and based on two Danish case studies and the perceptions of coworkers and social media coordinators. A deeper, summative analysis of ISM across more and various organizations in multiple countries has to confirm the findings.

Originality/value

The paper conceptualizes ISM as an interactive and dynamic communication arena, and proposes that the participatory communication on ISM is a co-constructed process among coworkers, middle managers and top managers.
Cascaded signal processing approach for motor fault diagnosis
Authors: Panigrahy Parth Sarathi , Chattopadhyay Paramita
Published: August 2018

Purpose

The purpose of this paper is to inspect strategic placing of different signal processing techniques like wavelet transform (WT), discrete Hilbert transform (DHT) and fast Fourier transform (FFT) to acquire the qualitative detection of rotor fault in a variable frequency drive-fed induction motor under challenging low slip conditions.

Design/methodology/approach

The algorithm is developed using Q2.14 bit format of Xilinx System Generator (XSG)-DSP design tool in MATLAB. The developed algorithm in XSG-MATLAB can be implemented easily in field programmable gate array, as a provision to generate the necessary VHDL code is available by its graphical user interface.

Findings

The applicability of WT is ensured by the effective procedure of base wavelet selection, which is the novelty of the work. It is found that low-order Daubechies (db) wavelets show decent shape matching with current envelope rather than raw current signal. This fact allows to use db1-based discrete wavelet transform-inverse discrete wavelet transform, where economic and multiplier-less design is possible. Prominent identity of 2sfs component is found even at low FFT points due to the application of suitable base wavelet.

Originality/value

The proposed method is found to be effective and hardware-friendly, which can be used to design a low-cost diagnostic instrument for industrial applications.
Factors influencing e-government adoption in India: a qualitative approach
Authors: Kumar Rajiv , Sachan Amit , Mukherjee Arindam , Kumar Ritu
Published: August 2018

Purpose

The purpose of this study is to explore the factors that enable citizens to adopt e-government services in India.

Design/methodology/approach

The study uses a qualitative approach by conducting semi-structured interviews.

Findings

The study reveals novel e-government adoption factors, namely, auxiliary facilities, corruption avoidance, transparency and fairness in process, customer support, connectedness and forced adoption, previously unexplored in e-government adoption literature. In addition, the results highlight 17 e-government adoption factors that strengthen the findings from previous literature.

Research limitations/implications

This study was qualitative in nature, and rather than generalization, the focus was explicitly on obtaining an in-depth understanding. The sample used was sufficient for the purpose of this study and allowed reasonable conclusions to be drawn; however, it cannot be considered representative of a vast country like India. Academicians and information systems researchers can use these findings for further research.

Practical implications

The findings of this study provide useful insights into the decision-making process of e-government services users in India and similar emerging economies. These findings can be important for government officials tasked with providing e-government services.

Originality/value

Previous studies in the context of e-government adoption, so far, have tried to integrate adoption factors from previous technology adoption models. Hence, these studies have not been able to capture the complete essence of e-government characteristics. In addition, there are limited studies in e-government adoption in the Indian context.
Design factors and preferences in wearable soft robots for movement disabilities
Authors: Koo Sumin Helen
Published: August 2018

Purpose

The purpose of this paper is to understand different preferences and important design factors for wearable soft robots (WSR) and understand how these differences affect people’s perception, attitude and behavioral intentions toward using the WSR.

Design/methodology/approach

An online survey was conducted to purposely sampled participants who are adults aged over 18 of both genders with movement disabilities living in the USA. The collected data were analyzed through Welch’s t-test, Welch’s analysis of variance and linear- and multi-regressions for quantitative data and major theme extractions for qualitative data.

Findings

The results identified preferred functions and designs and important design factors for WSR and how these influence to users’ perception, attitude and behaviors on WSR.

Originality/value

The number of people with movement disabilities is anticipated to increase worldwide and it is essential to understand users for developing wearable movement aids for people with movement disabilities. However, there is no research on what functions and designs are preferred by WSR users and what aspects designers need to consider when developing these WSR. Thus, this research will contribute to the body of knowledge in WSR design; help WSR developers, designers and researchers better incorporate users’ preferences in the design process; and ultimately enhance the quality of life of people who have movement disabilities.
Designing payroll levies for firm training
Authors: Lee Gregory John , Davison Alexander
Published: August 2018

Purpose

The purpose of this paper is to investigate and recommend formal guidelines for the initial design of country-level or sectoral payroll levy systems that are intended to incentivize new firm training. The paper presents and illustrates two necessary conditions for new training to be stimulated, one involving transaction costs and the other the incentive payback. Ultimately, the purpose is to guide more successful designs for such systems in future.

Design/methodology/approach

The paper is principally theoretical, but the South African levy-grant system of the late 1990s is used as a case study. The paper illustrates how World Bank data may have been used to guide the design.

Findings

The paper demonstrates how during the design phase, policy makers can employ knowledge of pre-incentive training levels of firms, and possibly also estimates of unit transaction costs, to estimate the number of employees that may be positively affected. In the South African case, the actual system used may have been underspecified and unlikely to reach many employees with new training.

Research limitations/implications

Future research may employ these guidelines in empirical studies of the relative success of payroll levies.

Practical implications

The practical value of the paper is formal guidelines for policy makers seeking to implement such payroll levy systems.

Social implications

Better design for these systems may have positive implications for productivity and social externalities while avoiding unnecessary waste.

Originality/value

While there have been several more general reflections of payroll levy systems, and empirical investigations of their efficacy, this is the first paper formally modeling and testing design guidelines that can be implemented practically in the pre-implementation phase.
Invisible disabilities: perceptions and barriers to reasonable accommodations in the workplace
Authors: Syma Carrye
Published: August 2018

Purpose

The subject of invisible disabilities is becoming more prevalent in the workplace. Invisible disabilities (as defined by the Invisible Disabilities Association) refers to symptoms such as “debilitating pain, fatigue, dizziness, cognitive dysfunctions, brain injuries, learning differences and mental health disorders, as well as hearing and vision impairments.” There are times when employees are hesitant to disclose their invisible disability to their employer or coworkers, which means that accommodations for disabilities may not be requested or made. Accommodations made in the workplace for invisible disabilities can include flexible schedule, special software for assisting with scheduling or prioritizing tasks, or architectural changes such as a standing desk. The paper aims to discuss these issues.

Design/methodology/approach

For this literature review, articles on invisible disabilities and accommodations were researched and used to support the importance of accommodations in the workplace.

Findings

Invisible disabilities are affecting the workplace and must be addressed. Those struggling with invisible disabilities need to consider sharing information about their disability with their employer as well as requesting accommodation. The question of whether or not to inform coworkers should be left to individual employees and what they feel comfortable divulging. More research needs to be done on how to create learning opportunities and sensitivity in the workplace to those with invisible disabilities. Perhaps training should be offered at the time a new employee begins work.

Originality/value

This literature review is of value because it speaks to an important issue facing today’s workplaces – invisible disabilities and accommodations. Mental illnesses are an invisible disability and as more people are diagnosed and enter the workforce, employers are faced with an increasing demand to meet the needs of these workers. Educating employers and employees on the topic of invisible disabilities and accommodations paves the way to a greater and more productive workforce.
Marketing academic library information services using social media
Authors: AlAwadhi Suha , Al-Daihani Sultan M.
Published: August 2018

Purpose

The purpose of this paper is to examine the use of social media in the marketing of academic library resources and services in Kuwait and identifies the factors related to the use of social media applications in marketing academic libraries.

Design/methodology/approach

A quantitative data-collection approach using a paper and online questionnaire has been employed to elicit the opinions of librarians working in academic libraries in Kuwait in both private and public institutions. In total, 89 valid questionnaires have been analyzed using descriptive (frequencies, percentages, means and standard deviations) and inferential statistics (factor analysis, correlations, experimental analysis and regression).

Findings

The study shows that the academic librarians have a positive perception toward the use of social media. The identified factors relating to the use of social media for marketing library information resources and services are the usefulness of social media tools in raising awareness and in providing needs analysis and satisfaction assessments. However, management support for the use of social media for library marketing is poor.

Practical implications

This study provides insights into the factors related to the use of modern social media platforms to promote information resources and services at academic libraries to provide outreach services to current and potential users.

Originality/value

This research contributes to the field of information studies as it highlights the importance of using social media platforms in marketing academic library information resources and services. Library administrators could use the results to develop social media marketing plans to effectively promote their library resources.
Ecological mechanisms and phylogeny shape invertebrate stoichiometry: A test using detritus‐based communities across Central and South America
Authors: González Angélica L. , Céréghino Régis , Dézerald Olivier , Farjalla Vinicius F. , Leroy Céline , Richardson Barbara A. , Richardson Michael J. , Romero Gustavo Q. , Srivastava Diane S.
Published: August 2018

Stoichiometric differences among organisms can affect trophic interactions and rates of nutrient cycling within ecosystems. However, we still know little about either the underlying causes of these stoichiometric differences or the consistency of these differences across large geographical extents.

Here, we analyse elemental (carbon, nitrogen, phosphorus) composition of 872 aquatic macroinvertebrates (71 species) inhabiting tank bromeliads (n = 140) from five distantly located sites across Central and South America to (i) test phylogenetic, trophic and body size scaling explanations for why organisms differ in elemental composition and (ii) determine whether patterns in elemental composition are universal or context dependent.

Taxonomy explained most variance in elemental composition, even though phylogenetic signals were weak and limited to regional spatial extents and to the family level. The highest elemental contents and lowest carbon:nutrient ratios were found in organisms at high trophic levels and with smaller body size, regardless of geographical location.

Carnivores may have higher nutrient content and lower carbon:nutrient ratios than their prey, as organisms optimize growth by choosing the most nutrient‐rich resources to consume and then preferentially retain nutrients over carbon in their bodies. Smaller organisms grow proportionally faster than large organisms and so are predicted to have higher nutrient requirements to fuel RNA and protein synthesis. Geography influenced the magnitude, more than the direction, of the ecological and/or phylogenetic effects on elemental composition.

Overall, our results show that both ecological (i.e. trophic group) and evolutionary drivers explain among‐taxa variation in the elemental content of invertebrates, whereas intraspecific variation is mainly a function of body size. Our findings also demonstrate that restricting analyses of macroinvertebrate stoichiometry solely to either the local scale or species level affects inferences of the patterns in invertebrate elemental content and their underlying mechanisms.

A plain language summary is available for this article.
A mimicked bacterial infection prolongs stopover duration in songbirds—but more pronounced in short‐ than long‐distance migrants
Authors: Hegemann Arne , Alcalde Abril Pablo , Sjöberg Sissel , Muheim Rachel , Alerstam Thomas , Nilsson Jan‐Åke , Hasselquist Dennis
Published: August 2018

Migration usually consists of intermittent travel and stopovers, the latter being crucially important for individuals to recover and refuel to successfully complete migration. Quantifying how sickness behaviours influence stopovers is crucial for our understanding of migration ecology and how diseases spread. However, little is known about infections in songbirds, which constitute the majority of avian migrants.

We experimentally immune‐challenged autumn migrating passerines (both short‐ and long‐distance migrating species) with a simulated bacterial infection. Using an automated radiotelemetry system in the stopover area, we subsequently quantified stopover duration, “bush‐level” activity patterns (0.1–30 m) and landscape movements (30–6,000 m).

We show that compared to controls, immune‐challenged birds prolonged their stopover duration by on average 1.2 days in long‐distance and 2.9 days in short‐distance migrants, respectively (100%–126% longer than controls, respectively). During the prolonged stopover, the immune‐challenged birds kept a high “bush‐level” activity (which was unexpected) but reduced their local movements, independent of migration strategy. Baseline immune function, but not blood parasite infections prior to the immune challenge, had a prolonging effect on stopover duration, particularly in long‐distance migrants.

We conclude that a mimicked bacterial infection does not cause lethargy, per se, but restricts landscape movements and prolongs stopover duration, and that this behavioural response also depends on the status of baseline immune function and migration strategy. This adds a new level to the understanding of how acute inflammation affect migration behaviour and hence the ecology and evolution of migration. Accounting for these effects of bacterial infections will also enable us to fine‐tune and apply optimal migration theory. Finally, it will help us predicting how migrating animals may respond to increased pathogen pressure caused by global change.
Effects of grasshoppers on prairies: Herbivore composition matters more than richness in three grassland ecosystems
Authors: Laws Angela N. , Prather Chelse M. , Branson David H. , Pennings Steven C.
Published: August 2018

Understanding how biodiversity affects ecosystem processes is a key question in ecology. Previous research has found that increasing plant diversity often enhances many ecosystem processes, but less is known about the role of consumer diversity to ecosystem processes, especially in terrestrial ecosystems. Furthermore, we do not know how general biodiversity responses are among ecosystem types.

We examined the role of insect herbivore (Orthoptera) diversity on plant production using parallel field experiments in three grassland ecosystems (mixed grass prairie, tallgrass prairie and coastal tallgrass prairie) to determine whether the effects of grasshopper diversity were consistent among sites.

Using mesocosms, we manipulated orthopteran species richness (0, 1, 2, 3 or 4 species), functional richness (number of functional feeding groups present; 0, 1 or 2 functional groups) and functional composition (composition of functional groups present; mixed‐feeders only, grass‐feeders only, both mixed‐feeders and grass‐feeders). Diversity treatments were maintained throughout the experiment by replacing dead individuals. Plant biomass was destructively sampled at the end of the experiment.

We found no effect of species richness or functional richness on plant biomass. However, herbivore functional composition was important, and effects were qualitatively similar across sites: The presence of only grass‐feeding species reduced plant biomass more than either mixed‐feeding species alone or both groups together. Orthopterans had consistent effects across a range of abiotic conditions, as well as different plant community and orthopteran community compositions.

Our results suggest that functional composition of insect herbivores affects plant communities in grasslands more than herbivore species richness or functional richness, and this pattern was robust among grassland types.
Producing Localized Commodity Frontiers at the End of Cheap Nature: An Analysis of Eco‐scalar Carbon Fixes and their Consequences
Authors: Schindler Seth , Kanai J. Miguel
Published: August 2018

There is no single ‘great’ commodity frontier whose exploitation under current socio‐technical conditions could fuel capital accumulation at the global scale. According to Jason Moore, this represents the ‘end of Cheap Nature’ and signals a terminal crisis for capitalism as we know it. In this article we complicate this assertion by showing how, in the context of global environmental governance frameworks of carbon control, a diverse range of actors situated at multiple scales are intensifying the use of cities and their hinterlands for the production/transgression of localized commodity frontiers. We draw on scholarship on uneven geographical development, state‐led restructuring and eco‐scalar fixes to present two case studies from different segments of the carbon cycle in the global South. The first case demonstrates how the introduction of waste‐to‐energy technology in Delhi facilitated the generation of ‘carbon credits’ while waste matter itself became a commodity. The second discusses attempts by the Brazilian state of Amazonas (Amazônia) aspiring to shift from rainforest exploitation to financialized conservation supported by the ‘green global city’ functions of metropolitan Manaus. These cases demonstrate that although the global carbon‐control regime may enable accumulation, implementation remains speculative, and localized commodity frontiers provoke social resistances that jeopardize their durability.
Amphibians in agricultural landscapes: the habitat value of crop areas, linear plantings and remnant woodland patches
Authors: Hansen N. A. , Scheele B. C. , Driscoll D. A. , Lindenmayer D. B.
Published: August 2018

Mitigating the negative impacts of agriculture on amphibians requires knowledge of how different land uses affect species distribution and community composition. In the case of frogs, there is currently insufficient information on their use of terrestrial habitats in cropping landscapes to inform conservation planning. We examined how four different farmland types (linear plantings, cereal crops, grazing paddocks and woody mulch) and crop harvesting influenced amphibian abundance, richness, body condition and movement. We found the abundance of frogs was significantly higher in linear plantings compared to grazing paddocks and adjacent patches of remnant woodland vegetation. However, species richness and abundance of three individual species did not vary significantly between farmland types. For the most common frog Uperoleia laevigata, body condition was higher at the edges of the woody debris treatment (coupled with higher abundance) and lower in farmland with debris and linear plantings. The body condition of Limnodynastes tasmaniensis and L. interioris was not influenced by farmland type. Frog abundance and condition was largely unaffected by crop harvesting. However, frogs were less common after harvesting at the edges of farmland and within remnant patches. Movement patterns did not suggest mass movement out of crops after harvest, where almost half of all individuals recaptured remained within the farmland. These results suggest that some generalist frog species may have an affinity for habitats within agricultural paddocks, particularly when key habitat features like plantings are present. However, we found overall frog richness was low and did not differ between remnant patches, edges and farmland which may be an indication of habitat degradation within terrestrial habitats across the landscape. Although protection of remnant native vegetation is important, conservation strategies for the protection of amphibians will be ineffective if they do not consider the variety of land uses and the relationships of different species and their microhabitats within and outside of patches.
Testing the Wiegand–Milton model: A long‐term experiment to understand mechanisms driving vegetation dynamics in arid shrublands
Authors: van der Merwe Helga , Milton Suzanne J.
Published: August 2018

The Wiegand and Milton (1996) simulation model predicts that vegetation dynamics in arid shrublands are characterized by event‐driven stochasticity (weather events), and demographic inertia (persistence of a species in a community) that lead to a lagged response in vegetation compositional change. Slow plant growth is one of the mechanisms driving slow vegetation change. We test this model at the same location (Tierberg Long‐term Ecological Research site) on which the model was based. Three dwarf shrub species, differing in palatability, were tracked over 25 years (1988–2014) at two levels of the past herbivory (pre‐1960) and three levels of the present herbivory (post‐1988). In the period between 1960 and 1988, all sites were grazed at the recommended agricultural stocking rate. For each species, plant density and a number of size attributes (basal diameter, height, canopy area) were surveyed. Analyses using a two‐way Analysis of Covariance (ANCOVA) took initial starting size into consideration. As the model predicted, event‐driven stochasticity (rainfall) resulted in an increase in density of the smaller size classes following a single large recruitment event across all grazing regimes for the palatable and unpalatable species. Size‐class distribution curve types remained unchanged illustrating that population demography remains unaffected for long periods and responses are slow (lagged response). Slow plant growth was evident in that there were no changes in height, canopy area, or density under present grazing regimes over the 25‐year period. Palatable species had a reduced canopy area and density compared to unpalatable species. Our findings provide empirical evidence supporting the predictions of the Wiegand and Milton (1996) model, notably event‐driven stochasticity, demographic inertia, and a lagged response in vegetation change in arid shrublands. In addition, our results support the model assumption of the significance of slow growth in long‐lived plant species and the influence of grazing regime.
Refuse attracts? Effect of refuse dumps of leaf‐cutting ants on floral traits
Authors: Fernandez Anahí , Tadey Mariana , Farji‐Brener Alejandro G.
Published: August 2018

The nutrient‐rich organic waste generated by ants may affect plant reproductive success directly by enhancing fruit production but also indirectly, by affecting floral traits related with pollinator attraction. Understanding how these soil‐nutrient hot spots influence floral phenotype is relevant to plant–pollination interactions. We experimentally evaluated whether the addition of organic waste from refuse dumps of the leaf‐cutting ant Acromyrmex lobicornis (Hymenoptera: Formicidae: Attini) alters floral traits associated with pollinator attraction in Eschscholzia californica (Ranunculales: Papaveraceae), an entomophilous herb. We analysed flower shape and size using geometric morphometric techniques in plants with and without the addition of refuse‐dumps soil, under greenhouse conditions. We also measured the duration of flowering season, days with new flowers, flower production and floral display size. Plants growing in refuse‐dumps soil showed higher flower shape diversity than those in control soil. Moreover, plants in refuse‐dumps soil showed bigger flower and floral display size, longer flowering season, higher number of flowering days and flower production. As all these variables may potentially increase pollinator visits, plants in refuse‐dumps soil might increase their fitness through enhanced attraction. Our work describes how organic waste from ant nests may enhance floral traits involved in floral attraction, illustrating a novel way of how ants may indirectly benefit plants.
In Vitro Hemocompatibility Evaluation of Ventricular Assist Devices in Pediatric Flow Conditions: A Benchmark Study
Authors: Chan Chris Hoi Houng , Diab Sara , Moody Kayla , Frazier O Howard , Sampaio Luiz C. , Fraser Charles D. , Teruya Jun , Adachi Iki
Published: August 2018

Development of pediatric ventricular assist devices (VADs) has significantly lagged behind that of adult devices. This frustrating reality is reflected by the fact that the Berlin Heart EXCOR VAD is currently the only approved pediatric‐specific device in the USA. An alternative option is an off‐label use of adult continuous‐flow VADs, such as HeartMate II (HMII), which inevitably causes patient‐device size mismatch in small children. We sought to conduct in vitro hemocompatibility testing in a pediatric flow condition, with a specific aim to provide benchmark values for future pediatric device development. Given the aforementioned fact that both pulsatile and continuous‐flow devices are being used in the pediatric population, we opted to test both types of devices in the present study. The EXCOR and HMII blood pumps were tested using bovine blood under constant hemodynamic conditions (flow rate, Q = 2.5 ± 0.25L/min; differential pressure across the pump, ΔP = 68 ± 5mm Hg). Hemolysis was measured by Harboe assay. There was a steady increase in plasma free hemoglobin during in vitro testing, with a statistically significant difference between 5 and 360 min for both EXCOR (P < 0.0001) and HMII (P < 0.001). However, the degree of an increase in plasma free hemoglobin was more significant with HMII (P < 0.001). Normalized index of hemolysis for EXCOR and HMII were 0.003 ± 0.0026g/100 L and 0.085 ± 0.0119g/100 L, respectively. There was also a steady increase in platelet activation detected by CAPP2A antibody using flow cytometry, with a statistically significant difference between 5 and 360 min for both devices (P < 0.05). The degree of an increase in platelet activation was similar between the two devices (P = 0.218). High molecular weight von Willebrand factor (HMW vWF) multimer degradation measured by immunoblotting was evident for both devices, however, it was more pronounced with the EXCOR. EXCOR blood samples from all three time points (120, 240, and 360 min) were significantly different from the baseline (5 min), whereas only 360 min samples had a significant difference from the baseline with the HMII. In conclusion, we have observed similarities and differences in hemocompatibility profiles between the EXCOR and HMII, both of which are commonly used in the pediatric population. We anticipate the benchmark values in the present study will facilitate future pediatric VAD development.
Peripheral Th17 cells expressing β7 intestinal homing receptor in recent and chronic HIV infections
Authors: Márquez-Coello M , Montes-de-Oca Arjona M , Fernández-Gutiérrez del Álamo C , Ruiz-Sánchez C , Girón-González J A
Published: August 2018

The objective of this study was to conduct an analysis of peripheral blood Th17 cells with the ability to home to gut mucosa (CD4+Th17+β7+) during recent or chronic human immunodeficiency virus (HIV) infections. The relationship between HIV load and systemic inflammation markers was studied. Twenty-five patients with recent (n = 10) or chronic (n = 15) untreated HIV infections; 30 treated HIV-infected patients with undetectable HIV load at the time of inclusion and 30 healthy controls were included. Bacterial translocation markers (16S rDNA), soluble CD14 (sCD14) and interleukin (IL)-6 monocyte activation parameters, CD4/CD8 ratio and T helper type 17 (Th17) subpopulations [CD4+Th17+ expressing the IL-23 receptor (IL-23R) or β7] were analysed at baseline and after 6 and 12 months of anti-retroviral therapy (ART). 16S rDNA was detected in all patients. Significantly increased serum levels of sCD14 and IL-6 and a decreased CD4/CD8 ratio were observed in patients. Similar percentages of CD4+IL-23R+ and CD4+Th17+β7+ cells were observed in healthy controls and patients at baseline. After 12 months of therapy, patients with a recent HIV infection showed significant increases of CD4+IL-23R+ and CD4+Th17+β7+ cell percentages and a decrease in IL-6 levels, although 16S rDNA continued to be detectable in all patients. No significant differences were observed in Th17 subpopulations in patients with chronic HIV infection after therapy. Early initiation of ART helps to increase the number of Th17 cells with the ability to home to the intestinal mucosa and to partially restore gut mucosal homeostasis. These results provide a rationale for initiating ART during the acute phase of HIV infection.