bluuebunny/crossref_metadata_2025 huggingface dataset:
Multi-channelin situdynamic light scattering instrumentation enhancing biological small-angle X-ray scattering experiments at the PETRA III beamline P12
Authors: Falke Sven , Dierks Karsten , Blanchet Clement , Graewert Melissa , Cipriani Florent , Meijers Rob , Svergun Dmitri , Betzel Christian
Published: February 2018

Small-angle X-ray scattering (SAXS) analysis of biomolecules is increasingly common with a constantly high demand for comprehensive and efficient sample quality control prior to SAXS experiments. As monodisperse sample suspensions are desirable for SAXS experiments, latest dynamic light scattering (DLS) techniques are most suited to obtain non-invasive and rapid information about the particle size distribution of molecules in solution. A multi-receiver four-channel DLS system was designed and adapted at the BioSAXS endstation of the EMBL beamline P12 at PETRA III (DESY, Hamburg, Germany). The system allows the collection of DLS data within round-shaped sample capillaries used at beamline P12. Data obtained provide information about the hydrodynamic radius of biological particles in solution and dispersity of the solution. DLS data can be collected directly prior to and during an X-ray exposure. To match the short X-ray exposure times of around 1 s for 20 exposures at P12, the DLS data collection periods that have been used up to now of 20 s or commonly more were substantially reduced, using a novel multi-channel approach collecting DLS data sets in the SAXS sample capillary at four different neighbouring sample volume positions in parallel. The setup allows online scoring of sample solutions applied for SAXS experiments, supports SAXS data evaluation and for example indicates local inhomogeneities in a sample solution in a time-efficient manner. Biological macromolecules with different molecular weights were applied to test the system and obtain information about the performance. All measured hydrodynamic radii are in good agreement with DLS results obtained by employing a standard cuvette instrument. Moreover, applying the new multi-channel DLS setup, a reliable radius determination of sample solutions in flow, at flow rates normally used for size-exclusion chromatography–SAXS experiments, and at higher flow rates, was verified as well. This study also shows and confirms that the newly designed sample compartment with attached DLS instrumentation does not disturb SAXS measurements.
Synthesis and crystal structures of (2E)-1,4-bis(4-chlorophenyl)but-2-ene-1,4-dione and (2E)-1,4-bis(4-bromophenyl)but-2-ene-1,4-dione
Authors: Lastovickova Dominika N. , La Scala John J. , Sausa Rosario C.
Published: February 2018

The molecular structure of (2E)-1,4-bis(4-chlorophenyl)but-2-ene-1,4-dione [C16H10Cl2O2, (1)] is composed of twop-chlorophenyl rings, each bonded on opposite ends to a near planar 1,4-transenedione moiety [–C(=O)—CH=CH—(C=O)–] [r.m.s. deviation = 0.003 (1) Å]. (2E)-1,4-Bis(4-bromophenyl)but-2-ene-1,4-dione [C16H10Br2O2, (2)] has a similar structure to (1), but with twop-bromophenyl rings and a less planar enedione group [r.m.s. deviation = 0.011 (1) Å]. Both molecules sit on a center of inversion, thusZ′ = 0.5. The dihedral angles between the ring and the enedione group are 16.61 (8) and 15.58 (11)° for (1) and (2), respectively. In the crystal, molecules of (1) exhibit C—Cl...Cl type I interactions, whereas molecules of (2) present C—Br...Br type II interactions. van der Waals-type interactions contribute to the packing of both molecules, and the packing reveals face-to-face ring stacking with similar interplanar distances of approximately 3.53 Å.
Vigilant resilience: the possibilities for renewal through preparedness
Authors: Carlson Elizabeth
Published: February 2018

Purpose

Post-crisis renewal discourse (Ulmer et al., 2007) is one form of communication that stakeholders may use as they attempt to organize for resilience. The purpose of this paper propose extending Discourse of Renewal Theory to explain how it could enact a different kind of resilience than scholars typically consider. Organizational resilience strategies often focus on the recovery or prevention stages of crisis management. Under conditions of persistent threat, it would be more productive for renewal discourse to emphasize greater preparedness.

Design/methodology/approach

To illustrate the need for this kind of theorizing, the author analyzes a case study that follows the public relations efforts of Canadian energy company Enbridge, Inc., in the aftermath of the 2010 Kalamazoo River oil spill.

Findings

By the criteria of Discourse of Renewal Theory, Enbridge attempted a renewal strategy, but it failed. By other criteria, however, it succeeded: it created the opportunity for richer dialogue among stakeholders about their interdependence and their competing interests.

Originality/value

By considering how elements of the resilience process may vary, this paper offers resources for more nuanced theory-building and theory-testing related to organizational and system-level resilience.
Revisiting high-reliability organizing: obstacles to safety and resilience
Authors: Ford Jessica L.
Published: February 2018

Purpose

The purpose of this paper is to complicate and critique contemporary scholarship on high-reliability organizations (HROs). This paper argues that although HRO scholarship helps to identify communicative patterns that facilitate reliability and safety, it also simplifies processes that undermine the effectiveness of existing recommendations for HROs.

Design/methodology/approach

This paper frames high-reliability organizing as the enactment of mindfulness, which is the theoretical mechanism behind each of the five principles of high-reliability organizing. Using this framework, this paper then elaborates on each of the HRO principles: preoccupation with failure, reluctance to simplify interpretations, sensitivity to operations, commitment to resilience, and deference to expertise.

Findings

This paper details how research guided by HRO theory must address the following obstacles to safety and resilience: information accessibility limiting preoccupation with failure, identity constructions encouraging the simplification of interpretations, message fatigue repressing sensitivity to operations, the information environment within HROs weakening commitment to resilience, and generational differences impeding deference to expertise.

Originality/value

This paper highlights key issues obstructing safety and reliability in organizations that have been largely ignored by extant literature and encourages scholars to do more to acknowledge the role communication plays in constituting and reconstituting organizational reliability. Failing to fully address complex communicative interactions in HROs obstructs efforts to safeguard employee health and safety.
(Dis)identification as resilience in dirty volunteer work
Authors: Ford Jacob Stuart
Published: February 2018

Purpose

The purpose of this paper is to investigate the role of identification and disidentification processes of individuals who perform dirty work. Specifically, this study seeks to understand how identification creates resilience for volunteer workers to endure dirty work.

Design/methodology/approach

The present study examines the resilience of volunteers in dirty work roles by interviewing 37 volunteers at an animal shelter and observing volunteers for 72 hours. The transcripts and field notes were analyzed using a grounded theory analysis.

Findings

Volunteers construct multiple identifications and disidentifications as part of the resilience process to engage dirty and dangerous work. Volunteers switched between different (dis)identifications and communicatively reinforced (dis)identifications to overcome the physical and social stigma associated with their work.

Originality/value

The present study extends research on resilience into a new context: dirty work. The findings bring into question assumptions regarding resilience and how a disruption is defined in the resilience literature. Disruptions are communicatively constructed and future studies should continue to research alternative contexts to study resilience labor.
Financial decisions and ownership structure as control mechanisms of agency problems: evidence from Italy
Authors: Rossi Fabrizio , Boylan Robert , Cebula Richard J.
Published: February 2018

Purpose

The purpose of this study is to investigate the relationship between financial decisions and ownership structure by using the control contests on a sample of Italian listed companies.

Design/methodology/approach

The analysis adopts a balanced panel data set of 984 firm-year observations for the period of 2002-2013, with estimation using a generalized method of moments.

Findings

The results appear to confirm both the hypotheses of the alignment of interests and the entrenchment effect. The entrenchment and alignment effects are not found to be alternatives but rather are found to co-exist. The presence of a coalition of minority shareholders acts as a tool to control agency costs, particularly when the coalition is instrumental in the contestability of corporate control.

Practical implications

These findings suggest that minority shareholders may have a larger impact than previously identified by strategically aligning with other shareholders to form coalitions. This study provides several practical implications. First, dividend payout is not necessarily a good instrument to control and monitor agency costs. This is because the payout can be used to expropriate benefits from the minority shareholders. Second, high ownership concentration does not always reduce agency costs. Third, a non-collusive coalition can be more useful in the monitoring of agency costs than other tools, such as the debt level.

Originality/value

This study shows that there is considerable value to the firm when individual blockholders come together in a contestable environment and become instrumental in making business decisions. The results support the contention that contestability is an excellent deterrent to dampen the expropriation of benefits to minority shareholders. This study also provides evidence that cash holding can be a good substitute for dividends and debt in the effort to limit agency costs.
Consumer’s intention to use self-service parcel delivery service in online retailing
Authors: Chen Yuangao , Yu Jing , Yang Shuiqing , Wei June
Published: February 2018

Purpose

Online retailers widely use self-service parcel delivery as a solution to the last-mile logistics problems. The purpose of this paper is to investigate the factors that affect the consumer’s intention to use self-service parcel delivery service.

Design/methodology/approach

The authors integrate prior research and propose a comprehensive three-factor model. The study combines individual and situational factors and proposes a socialized factor.

Findings

This study found that location convenience, optimism, innovation, and the need for human interaction positively affect the consumer’s intention to avail of the self-service parcel delivery service. It also identifies that socialized factor positively influences the consumer’s intention to use self-service parcel delivery services.

Research limitations/implications

The test results show that the explanatory power of the individual factors of the model is better than that of the situational factors. However, this does not imply that the situational factors cannot explain the consumer behavior well. Future studies should employ additional situational factors to explain the consumer behavior.

Practical implications

This study offers valuable theoretical and managerial implications. Delivery service providers should concentrate on their marketing force and customize their services for consumer groups who have specific individual characteristics, such as optimism and innovation.

Social implications

Strengthening service interactions in the social factor and choosing optimal locations for self-service pickup machines are also essential for the expansion of the users’ population and enhancement of service experience.

Originality/value

The authors combined situational and individual factors, proposed a socialized factor, and presented the three-factor model of the consumer’s intention to use self-service parcel delivery service.
Individualism and internet addiction: the mediating role of psychological needs
Authors: Arpaci Ibrahim , Kesici Şahin , Baloğlu Mustafa
Published: February 2018

Purpose

The purpose of this paper is to investigate the mediating role of psychological needs in the association between individualism and internet addiction.

Design/methodology/approach

A mixed-method design was used by comprising of 602 college students’ (70.3 percent women) responses obtained through the Individualism-Collectivism Survey, New Needs Assessment Questionnaire, and Internet Addiction Scale. Structural equation modeling techniques were used to investigate the theoretical relationships among the constructs. Constant comparative method was employed to analyze qualitative data that resulted from the transcription of semi-structured interviews with 12 field experts.

Findings

Quantitative results showed that individualism has a significant effect on internet addiction through affiliation, dominance, achievement, and autonomy (i.e. psychological needs). As students’ needs for dominance, achievement, and autonomy increased their internet addiction levels decreased. However, increase in the need of affiliation led to increase in the likelihood of internet addiction. Qualitative findings suggested alternative ways to satisfy psychological needs in socially more proper ways.

Originality/value

Psychological needs and internet addiction have long been investigated both independently and in relation to each other. However, the investigation of espoused culture (i.e. individualism) in relation to psychological needs and internet addiction is relatively recent. A review of the recent literature showed that an investigation of the mediating role of psychological needs in the effect of individualism on internet addiction is highly original. Moreover, initial quantitative results and follow-up qualitative findings help the authors understand psychological needs underlying internet addiction and suggest socially more appropriate means to satisfy these needs. Findings have theoretical values for researchers as well as practical values for those who work with students.
External knowledge sharing and radical innovation: the downsides of uncontrolled openness
Authors: Ritala Paavo , Husted Kenneth , Olander Heidi , Michailova Snejina
Published: February 2018

Purpose

Inter-firm collaborative innovation typically requires knowledge sharing among individuals employed by collaborating firms. However, it is also associated with considerable risks, especially if the knowledge sharing process is not handled using proper judgment. Such risks have been acknowledged in the literature, but the underlying empirical evidence remains unclear. This study aims to examine how sharing of business-critical knowledge with external collaboration partners affects firm’s innovation performance.

Design/methodology/approach

The authors develop a mediating model and hypotheses predicting that the uncontrolled sharing of knowledge leads to accidental knowledge leakage, which, in turn, hinders particularly firm’s radical innovation performance. The authors test the model by using a survey of 150 technology-intensive firms in Finland and a partial least squares structural equation model. The mediating model is tested with incremental and radical innovation performance, and the authors control for firm size, age, R&D intensity and industry.

Findings

The authors find strong support for the model in that uncontrolled external knowledge sharing leads to accidental knowledge leaking and to lower radical innovation performance. The same results are not found for incremental innovation, implying that uncontrolled knowledge leakage is especially detrimental to radical innovation.

Originality/value

These findings help in better understanding some of the downsides of too much openness and lack of judgment about knowledge sharing beyond the boundaries of the firm. Thus, firms pursuing radical innovation should carefully guide their employees with regard to what knowledge they share, to what extent they share it and with whom they share it.
Strategic knowledge management in subsidiaries and MNC performance. The role of the relational context
Authors: Claver-Cortés Enrique , Zaragoza-Sáez Patrocinio , Úbeda-García Mercedes , Marco-Lajara Bartolome , García-Lillo Francisco
Published: February 2018

Purpose

Based on the knowledge-based theories of the MNC, this research aims to develop and test a holistic model to analyse the relationship between the strategic knowledge management (SKM) processes undertaken by subsidiaries and MNC performance. Additionally, it focuses on determining the impact that the relational context can have on knowledge creation and transfer inside the internal network of an MNC.

Design/methodology/approach

The research hypotheses are tested by partial least squares (PLS) with data from a sample of Spanish subsidiaries of foreign multinational firms belonging to high-technology and knowledge-intensive sectors.

Findings

The results confirm that: the implementation of a SKM by a subsidiary positively impacts on knowledge creation; the knowledge created by a subsidiary positively influences knowledge transfer, increasing the knowledge existing in the MNC; the knowledge transfer across all MNC units has a positive impact on MNC performance; the subsidiary’s relational context arises as a mediating variable between the knowledge created by a subsidiary and its transfer to the rest of the MNC.

Originality/value

The research proposes a holistic model that contemplates the joint interaction of the variables knowledge creation, knowledge transfer and performance. In addition, the proposed model contemplates the variable SMK of the subsidiary as the beginning of the knowledge creation-knowledge transfer-performance process. Finally, the mediating role of the relational context in the relationship between knowledge creation and transfer is analysed.
Do environmental management systems affect the knowledge management process? The impact on the learning evolution and the relevance of organisational context
Authors: Biscotti Anna Maria , D’Amico Eugenio , Monge Filippo
Published: February 2018

Purpose

The purpose of this study is to investigate how an environmental management system (EMS) might affect the environmental product innovation propensity of a firm through its influence on two factors shaping the knowledge process: the human capital management practices of training and development and the organisational context.

Design/methodology/approach

To test the study’s hypotheses, an empirical analysis was carried out on 262 companies drawn from 16 developed European markets included in the S&P Europe 350 Dow Jones index over the years 2005-2015.The authors adopted regression analysis by using the ordinary least squares and the binary logit econometric models.

Findings

Consistently with the study’s predictions, results show that for organisational contexts characterised by the presence of family owners, the EMAS-certified EMS reveals as a significant moderating factor that positively influences their approach to the knowledge management tools for the improvement of the workforce cognitive capabilities, with a significant impact on the firm’s openness towards green product innovation. On the contrary, the ISO 14001-certified EMS tends not to stimulate such proactive behaviour, in both family and non-family firms.

Practical implications

The findings suggest that an EMS can stimulate the knowledge exploration in the environmental protection field. To this end, top managers should overcome the bureaucratic vision of an EMS and conceive it as a knowledge management tool able to support the learning evolution of the organisation through an effective commitment to human capital management policies of training and development.

Originality/value

Drawing from social identity and institutional theories, this is the first study – to the best of the authors’ knowledge – that theorises and tests why the adoption of an EMS might stimulate the knowledge advancement of the organisation in a different way, especially in peculiar organisational contexts of family firms where the identity overlap between the family and the firm tends to affect the knowledge management process.
The continuing search for the Holy Grail
Authors: Wiseman Robert M. , Faqihi Hadi
Published: February 2018

Purpose

The purpose of this paper is to enrich the finding by Aguinis et al. (2018) that there is little overlap between the extremes of firm performance and the extremes of CEO pay using a novel approach to characterize the distribution of pay and performance. The authors aim to shift the focus of compensation researchers from fruitlessly trying to link pay to performance to theory-rich accounts of pay that take into consideration the idiosyncratically motivated and socially embedded nature of CEO compensation.

Design/methodology/approach

The authors’ approach in this commentary is conceptual. They synthesize compensation literature from different fields such as economics, finance, sociology, strategic management and corporate law, as well as the empirical findings from the focal paper to support their characterization of the current state of the literature and future directions it should take.

Findings

The authors synthesize discussion of CEO pay down to three dimensions of CEO responsibilities and motivations. They argue that a realistic pay design should take into account that CEOs have limited control over performance, they are accountable to multiple stakeholders and they are motivated by financial as well as nonfinancial incentives.

Originality/value

The commentary presents researchers with high-order framing of CEO pay that goes beyond debating over methodology or narrowly focusing on limited behavioral drivers of pay setting. Instead, the authors encourage researchers to take advantage of their three-legged framework to theorize about CEO pay.
Residual free solder process for fluxless solder pastes
Authors: Hanss Alexander , Elger Gordon
Published: February 2018

Purpose

For soldering, flux is essential because it enables the wetting of the molten solder. Fluxless soldering, i.e. residue-free soldering with the aid of gaseous activators, has been known for many years, but is only well established in the field of opto- and microwave electronics where the solder is applied as preform. In high-volume SMD applications where solder paste is printed, this technology is rarely used until now. The reducing effect of a gaseous activator like formic acid vapor on certain solder alloys is known in practice. However, the corresponding reactions which occur under soldering conditions in nitrogen atmosphere have so far not been systematically investigated for different solder alloys. This study aims to analyze the different chemical reaction channels which occur on the surface of different solders, i.e. catalytical dissociation of formic acid on the pure or oxidized metal surface and the formation and evaporation of metal formates. Based on this analysis, a residue-free solder process under formic acid is developed for solder paste applications.

Design/methodology/approach

In this paper, different solder alloys (SnAgCu, SnPb, BiSn, In) were analyzed with thermal gravimetric analysis (TGA) under formic acid flow. Details on mass change depending on the soldering temperature are presented. Activation temperatures are estimated and correlated to the soldering processes. Based on the analysis, fluxless solder pastes and suitable soldering processes are developed and presented. Major paste properties such as printability are compared to a commercial flux solder paste. High-power flip chip LEDs which can be assembled directly on a printed circuit board are used to demonstrate the fluxless soldering. Likewise, the soldering results of standard paste and fluxless paste systems after a reflow process are evaluated and compared.

Findings

The experimental results show that TGA is an efficient way to gain deeper understanding of the redox processes which occur under formic acid activation, i.e. the formation of metal formates and their evaporation and dissociation. It is possible to solder residue-free not only with preforms but also with a fluxless solder paste. The resulting solder joints have the same quality as those for standard solder paste in terms of voids detected by X-ray and mechanical shear strength.

Originality/value

In the fluxless soldering process, the reduction of oxide layers, and therefore the wetting of the solder spheres, is enabled by gaseous formic acid. After the soldering process, no cleaning process is necessary because no corrosive residues are left on the circuit boards and components. Therefore, soldering using solder paste without aggressive chemical ingredients has a high market potential. Expensive preforms could be replaced by paste dispensing or paste printing.
Mycorrhizal symbioses influence the trophic structure of the Serengeti
Authors: Stevens Bo Maxwell , Propster Jeffrey , Wilson Gail W. T. , Abraham Andrew , Ridenour Chase , Doughty Christopher , Johnson Nancy Collins
Published: February 2018

It is known that tropical grasslands such as Serengeti host large populations of arbuscular mycorrhizal (AM) fungi and that they respond to abiotic and biotic factors. It is also known that AM symbioses are important for the uptake of essential plant nutrients, which, in turn, influences the biomass and nutritional quality of herbivores and their predators. The purpose of this study was to investigate the influence of AM symbioses on the biomass of different trophic levels of an ecosystem.

To do this, we first measured the neutral lipid fatty acid biomarker 16:1ω5 to estimate the biomass of AM fungi in a long‐term grazing exclusion experiment. Then, we used model selection of Bayesian linear regressions to infer the primary factors that influence AM fungal biomass. Using model selection of different combinations of soil characteristics, we selected the best model using the leave‐one‐out cross‐validation information criterion. Finally, we used the Madingley model to simulate the influence of AM fungi on higher trophic levels. We combined spatially explicit information about soil phosphorus and AM fungal biomass to explore the emergent patterns of the Serengeti resulting from AM symbioses.

Our Bayesian analysis indicated that total soil phosphorus was the strongest predictor of AM fungal biomass, and there were significant interactions with grazing. Arbuscular mycorrhizal fungal biomass is lowest in soil where phosphorus is limited and increases with increasing phosphorus concentration. Biomass was also significantly higher in plots that were not grazed. The Madingley model indicated that nutritional benefits of AM symbioses maintain a substantial proportion of the biomass across all trophic levels.

Synthesis. Our analysis shows that inputs of phosphorus through arbuscular mycorrhizal symbioses substantially increase the ability of plants to grow and maintain nutritional quality, cascading through the biomass of consumers and predators in the ecosystem. Although they account for less than 1% of the total modelled biomass, the predicted nutritional benefit provided by arbuscular mycorrhizal fungi increased the biomass of macro‐organisms in the Serengeti by 48%. When considering the management of biodiversity, future ecosystem models should account for the influence of arbuscular mycorrhizal fungi on all trophic levels.
Fungal community shifts underpin declining mycelial production and turnover across a Pinus sylvestris chronosequence
Authors: Hagenbo Andreas , Kyaschenko Julia , Clemmensen Karina E. , Lindahl Björn D. , Fransson Petra
Published: February 2018

Fungi play critical roles in ecosystem processes such as decomposition and nutrient cycling, but have also been highlighted as significant contributors to organic matter build‐up in boreal forest soils. Ectomycorrhizal (ECM) mycelial biomass and necromass dynamics have recently been highlighted as essential for regulating build‐up of soil organic matter. Understanding the extent to which shifts in mycelial community or growth trait composition cause changes in mycelial production and turnover over ecological gradients would aid a mechanistic understanding of these important processes at an ecosystem scale.

Here, we test the hypotheses that shifting species and mycelial trait (exploration type) composition within the mycelial community underpin changes in biomass turnover with increasing forest age. We quantified mycelial turnover and assessed fungal community composition in a chronosequence of eight, 12‐ to 158‐year‐old, managed Pinus sylvestris forests. Turnover was estimated by determining mycelial biomass (ergosterol) in a sequence of ingrowth mesh bags and applying mathematical models. Fungal communities in the bags were identified using Pacific Biosciences sequencing of fungal ITS2 amplicons. To evaluate the accuracy of this method to represent all ECM fungi, community composition in bags was followed over time and compared with communities in soil.

Mycelial communities changed with stand age, but we found no evidence that there were concurrent shifts in mycelial exploration types. Forest age and turnover were significantly correlated with ECM mycelial community composition and collectively explained 39.4% of total variation. The similarity between fungal communities in mesh bags and in soil was strongly forest age dependent, with communities in mesh bags diverging from soil communities in stands older than 60 years. However, in all stands, when bag incubation time exceeded 75 days, communities became more similar to soil communities.

Synthesis. Our results support the idea that shifts in fungal community composition underpin the forest age‐related decrease in mycelial turnover; however, since ingrowth mesh bags exclude some mycorrhizal species in older forests, it remains a possibility that turnover estimates were not reflecting the entire community. While we found no evidence that mycelial exploration types of fungi changed systematically with forest age, we suggest that other traits that relate to biomass turnover and necromass degradation require further study, as they may explain the extent to which ectomycorrhizal fungi regulate and contribute to soil organic matter accumulation.
Association of ectomycorrhizal trees with high carbon‐to‐nitrogen ratio soils across temperate forests is driven by smaller nitrogen not larger carbon stocks
Authors: Zhu Kai , McCormack M. Luke , Lankau Richard A. , Egan J. Franklin , Wurzburger Nina
Published: February 2018

The distribution of mycorrhizal associations across biomes parallels a distinct gradient of soil carbon (C) and nitrogen (N) stocks, raising the question of how mycorrhizal traits relate to ecosystem properties. Arbuscular mycorrhizal (AM) and ectomycorrhizal (EM) hosts and fungi employ contrasting strategies for N acquisition, which may manifest in differences in soil C and N pools and/or soil C:N. However, cross‐biome comparisons are confounded with climatic and edaphic gradients as well as phylogenetic and functional trait distributions of component plant species. Here, we test emerging hypotheses that soil C, N and C:N are related to the dominance of EM trees within a temperate forest region where AM and EM trees largely coexist but vary in local abundance.

To determine the importance of mycorrhizal type on soil C and N, we analysed data from c. 1,000 forest inventory plots in the eastern United States. For each plot, we quantified the dominance of trees with different mycorrhizal associations and accounted for potentially confounding variables including phylogeny (angiosperm or gymnosperm), leaf N, soil clay content and climate. We used hierarchical Bayesian models to determine how these variables explained the patterns of soil C and N in the forest floor and mineral soil layers.

Increasing EM dominance was associated with higher C:N across all soil layers. This relationship remained even after accounting for tree phylogeny, leaf N content, soil clay content, temperature and precipitation, which were all important for explaining soil C:N. However, this mycorrhizal pattern of soil C:N was not related to increases in soil C content; rather, increasing EM dominance was associated with reductions in soil N.

Synthesis. Our findings are consistent with the proposition that mycorrhizal associations are related to terrestrial ecosystem properties. The mycorrhizal effect on soil C:N may result from differences in how arbuscular mycorrhizal and ectomycorrhizal plants interact with their fungal symbionts, decomposers and organic matter, to sustain differential cycling of C and N. Alternatively, these patterns could arise from differential success of the two mycorrhizal types in contrasting soil conditions; both processes may occur simultaneously, leading to a self‐reinforcing positive feedback.
Interactions among decaying leaf litter, root litter and soil organic matter vary with mycorrhizal type
Authors: Jacobs Luke M. , Sulman Benjamin N. , Brzostek Edward R. , Feighery John J. , Phillips Richard P.
Published: February 2018

Root‐derived inputs are increasingly viewed as primary controls of soil organic matter (SOM) formation; however, we have a limited understanding of how root decay rates depend on soil factors, and how decaying roots influence the breakdown of leaf litter and SOM.

We incubated root and leaf litter (alone and in combination) from arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM) trees in soils collected from forest plots dominated by AM and ECM trees in a factorial design. In each microcosm, we quantified litter decay rates and the effects of decaying litters on soil C balance. We hypothesized that (1) AM root litters would decompose faster than ECM root litters, (2) root litter decay would be greatest when decomposed in “home” soils (e.g. AM litters in AM soils and ECM litters in ECM soils) and (3) root and leaf litters would decompose faster when decaying in the same microcosms than when decaying in separate microcosms, resulting in the largest CO2 losses.

Overall, AM root litter decomposed faster than ECM root litter, and the magnitude of this effect depended on soil origin. AM litters decayed fastest in AM soils, but ECM and mixed AM–ECM litters were unaffected by soil origin. Decaying roots increased leaf litter mass loss, but only in microcosms containing soils of the same origin (e.g. AM litters in AM soils; mixed litters in mixed soils).

Carbon losses were dominated by microbial respiration, and the magnitude of this flux depended on litter type and soil origin. When leaves and roots decayed together, respiratory losses exceeded those from microcosms containing leaves and roots alone, with the largest losses occurring in each litters' “home” soil. In AM soils, elevated losses were driven by roots accelerating leaf decay, while in ECM soils, elevated losses resulted from roots and leaves accelerating the decay of SOM; in mixed soils, root‐induced increases in leaf and SOM decay contributed to elevated C losses.

Synthesis. Our results suggest that root, leaf and SOM decay are intertwined, and that measurements of these processes in isolation may lead to incorrect estimates of the magnitude and source of C losses from soils.
From mycorrhizal fungal traits to ecosystem properties – and back again
Authors: Wurzburger Nina , Clemmensen Karina E.
Published: February 2018

Mycorrhizal fungi are known for their functional importance in plant growth and nutrition, and because these symbiotic fungi represent a fundamental linkage between plants and soils, they likely underpin a number of biogeochemical processes in ecosystems. However, our ability to isolate and quantify their role in ecosystems has remained a challenge.

This special feature presents seven new studies that advance our understanding of how mycorrhizal fungi contribute to ecosystem function. We specifically highlight two complementary approaches by which ecologists are gaining insight: focusing on mycorrhizal fungal traits to target the biological mechanisms that scale up to the ecosystem, and capturing patterns and processes across ecosystems to understand the net effect of complex plant–fungal–soil interactions.

The studies in our special feature provide evidence that traits both within and across species of mycorrhizal fungi can contribute to ecosystem processes, and that disturbance from global change and management may result in altered mycorrhizal traits and lead to compromised ecosystem function. From a broader perspective, studies also demonstrate that key ecosystem properties vary over gradients of mycorrhizal dominance and time, suggesting that mycorrhizal effects emerge from complex interactions within ecosystems

Synthesis. Employing complementary approaches to the study of mycorrhizal ecology may allow us to isolate the mycorrhizal traits that matter most for ecosystem properties, as well as the suite of ecosystem properties that result from mycorrhizal fungi, thus converging on biogeochemical mechanisms that underpin terrestrial ecosystem function.
Quantifying Magnitude of Group‐Level Differences in Patient Experiences with Health Care
Authors: Quigley Denise D. , Elliott Marc N. , Setodji Claude Messan , Hays Ron D.
Published: February 2018

Objective

Review approaches assessing magnitude of differences in patient experience scores between different providers.

Data Sources

1990–2016 literature.

Study Design

Systematic literature review.

Data Extraction Methods

Of 812 articles mentioning “CAHPS,” “patient experience,” “patient satisfaction,” “important(ce),” “difference,” or “significance,” we identified 79 possible articles, yielding 35 for data abstraction. We included 22 articles measuring magnitude of differences in patient experiences.

Principal Findings

We identified three main ways of estimating magnitude of differences in patient experience scores: (1) by distribution/range of patient experience variable, (2) against external anchor, and (3) comparing a difference in patient experience on one covariate to differences in patient experience on other covariates.

Conclusions

We suggest routine estimation of magnitude in patient experience research. More work is needed documenting magnitude of differences between providers to make patient experience data more interpretable and usable.
Understanding the factors that influence household use of clean energy in the Similipal Tiger Reserve, India
Authors: Dash Madhusmita , Behera Bhagirath , Rahut Dil Bahadur
Published: February 2018

Biotic pressure in and around protected areas (PA) is the primary cause of biodiversity loss in many developing countries across the globe. The pressure comes partly from biomass energy dependency in the form of heavy extraction of fuelwood from the forests. Although biomass fuels provide easily accessible and affordable sources of domestic energy to the rural masses, their combustion results in environmental and health‐related hazards. The objectives of this paper are to assess the patterns of household energy use in a subsistence forest economy and analyze the factors that influence their energy use choice for cooking and lighting. The paper uses primary data collected randomly from 244 households located in and around the Similipal Tiger Reserve (STR), situated in the eastern Indian state of Odisha. Age of the household head, number of days in wage employment, number of adult males and females in a household, education of the household head and landholding size are found to be the major variables that determine household fuelwood collection sources inside the reserve. Considering household structure as an income indicator, the analysis clearly shows that non‐poor households prefer to use clean energy (i.e. solar) for lighting, while poor households tend to use solid fuel. Energy policies for development should be based on the realistic proposition that fuelwood will remain the major source of energy for cooking for substantial proportions of the world’s population. Promotion of public education, social forestry schemes and fuel‐efficient improved chulhas should be encouraged in order to reduce household dependence on fuelwood. Moreover, devolving sufficient property rights over forest resources to local communities may help secure their broad‐based and active participation in the decision‐making process, which may result in a positive change in the attitude of the local people towards biodiversity conservation.
Environmental variation shifts the relationship between trees and scatterhoarders along the continuum from mutualism to antagonism
Authors: SAWAYA Gina M. , GOLDBERG Adam S. , STEELE Michael A. , DALGLEISH Harmony J.
Published: February 2018

The conditional mutualism between scatterhoarders and trees varies on a continuum from mutualism to antagonism and can change across time and space, and among species. We examined 4 tree species (red oak [Quercus rubra], white oak [Quercus alba], American chestnut [Castanea dentata] and hybrid chestnut [C. dentata × Castanea mollissima) across 5 sites and 3 years to quantify the variability in this conditional mutualism. We used a published model to compare the rates of seed emergence with and without burial to the probability that seeds will be cached and left uneaten by scatterhoarders to quantify variation in the conditional mutualism that can be explained by environmental variation among sites, years, species, and seed provenance within species. All species tested had increased emergence when buried. However, comparing benefits of burial to the probability of caching by scatterhoarders indicated a mutualism in red oak, while white oak was nearly always antagonistic. Chestnut was variable around the boundary between mutualism and antagonism, indicating a high degree of context dependence in the relationship with scatterhoarders. We found that different seed provenances did not vary in their potential for mutualism. Temperature did not explain microsite differences in seed emergence in any of the species tested. In hybrid chestnut only, emergence on the surface declined with soil moisture in the fall. By quantifying the variation in the conditional mutualism that was not caused by changes in scatterhoarder behavior, we show that environmental conditions and seed traits are an important and underappreciated component of the variation in the relationship between trees and scatterhoarders.
Cognition and the brain of brood parasitic cowbirds
Authors: SHERRY David F. , GUIGUENO Mélanie F.
Published: February 2018

Cowbirds are brood parasites. Females lay their eggs in the nests of other species, which then incubate the cowbird eggs and raise the young cowbirds. Finding and returning to heterospecific nests presents cowbirds with several cognitive challenges. In some species, such as brown‐headed cowbirds (Molothrus ater), females but not males search for and remember the locations of potential host nests. We describe recent research on sex differences in cognition and the hippocampus associated with this sex difference in search for host nests. Female brown‐headed cowbirds perform better than males on some, but not all, tests of spatial memory and females show a pattern of adult hippocampal neurogenesis not found in males or in closely related non‐parasitic birds. Because of the apparent specialization of the hippocampus, brown‐headed cowbirds may be a good model in which to examine spatial information processing in the avian hippocampus and we also describe recent research on the spatial response properties of brown‐headed cowbird hippocampal neurons.
Climate change, thermal niches, extinction risk and maternal‐effect rescue of toad‐headed lizards, Phrynocephalus, in thermal extremes of the Arabian Peninsula to the Qinghai—Tibetan Plateau
Authors: SINERVO Barry , MILES Donald B. , WU Yayong , MÉNDEZ‐DE LA CRUZ Fausto R. , KIRCHHOF Sebastian , QI Yin
Published: February 2018

Determining the susceptibility of species to changing thermal niches is a major goal for biologists. In this paper we develop an eco‐physiological model of extinction risk under climate change premised on behavioral thermoregulation. Our method downscales operative environmental temperatures, which restrict hours of activity of lizards, hr, for present‐day climate (1975) and future climate scenarios (2070). We apply our model using occurrence records of 20 Phrynocephalus lizards (or taxa in species complexes) drawn from literature and museum records. Our analysis is phylogenetically informed, because some clades may be more sensitive to rising temperatures. The limits for computed hr predict local extirpations among Phrynocephalus lizards at continental scales and delineate upper boundaries of thermal niches as defined by Extreme Value Distributions. Under the 8.5 Representative Concentration Pathway scenario, we predict extirpation of 64% of local populations by 2070 across 20 Phrynocephalus species, and 12 are at high risk of total extinction due to thermal limits being exceeded. In tandem with global strategies of lower CO2 emissions, we propose regional strategies for establishing new national parks to protect extinction‐prone taxa by preserving high‐elevation climate refugia within existing sites of species occurrence. We propose that evolved acclimatization — maternal plasticity — may ameliorate risk, but is poorly studied. Previous studies revealed that adaptive maternal plasticity by thermoregulating gravid females alter progeny thermal preferences by ±1 °C. We describe plasticity studies for extinction‐prone species that could assess whether they might be buffered from climate warming — a self‐rescue. We discuss an epigenetic framework for studying such maternal‐effect evolution.
Effects of rodent abundance and richness on cache pilfering
Authors: DITTEL Jacob W. , VANDER WALL Stephen B.
Published: February 2018

Scatterhoarding is a common behavioral strategy to conserve food during periods of scarcity, but this type of food storage is vulnerable to theft or pilferage. A variety of environmental factors and cache characteristics influence the rate of pilferage. Here we investigate 2 environmental factors, which heretofore have not received much attention: the abundance and species richness of scatterhoarding animals in the vicinity of scatterhoarded seeds. We measured the rate of cache pilferage at 7 sites that differed in the number and species composition of granivorous rodents in western Nevada using local native seeds and sunflower seeds. We found that there was no difference between the pilferage rate of native seeds and sunflower seeds, but that sites with different rodent abundances had different pilferage rates. Pilferage rates were proportional to the abundance of scatterhoarding rodents. Scatterhoarding rodents removed seeds at the rate of 1.3%/day/rodent individual. Species richness of scatterhoarding rodents was not correlated with rates of pilferage. These results suggest that density‐dependent competition for scatterhoarded seeds is a strong determinant of pilferage rates.