bluuebunny/crossref_metadata_2025_split huggingface dataset:
Asymmetric warming significantly affects net primary production, but not ecosystem carbon balances of forest and grassland ecosystems in northern China
Authors: Su Hongxin , Feng Jinchao , Axmacher Jan C. , Sang Weiguo 
Published: March 2015

AbstractWe combine the process-based ecosystem model (Biome-BGC) with climate change-scenarios based on both RegCM3 model outputs and historic observed trends to quantify differential effects of symmetric and asymmetric warming on ecosystem net primary productivity (NPP), heterotrophic respiration (Rh) and net ecosystem productivity (NEP) of six ecosystem types representing different climatic zones of northern China. Analysis of covariance shows that NPP is significant greater at most ecosystems under the various environmental change scenarios once temperature asymmetries are taken into consideration. However, these differences do not lead to significant differences in NEP, which indicates that asymmetry in climate change does not result in significant alterations of the overall carbon balance in the dominating forest or grassland ecosystems. Overall, NPP, Rh and NEP are regulated by highly interrelated effects of increases in temperature and atmospheric CO2 concentrations and precipitation changes, while the magnitude of these effects strongly varies across the six sites. Further studies underpinned by suitable experiments are nonetheless required to further improve the performance of ecosystem models and confirm the validity of these model predictions. This is crucial for a sound understanding of the mechanisms controlling the variability in asymmetric warming effects on ecosystem structure and functioning.
Multiplexity versus correlation: the role of local constraints in real multiplexes
Authors: Gemmetto V. , Garlaschelli D. 
Published: March 2015

AbstractSeveral systems can be represented as multiplex networks, i.e. in terms of a superposition of various graphs, each related to a different mode of connection between nodes. Hence, the definition of proper mathematical quantities aiming at capturing the added level of complexity of those systems is required. Various steps in this direction have been made. In the simplest case, dependencies between layers are measured via correlation-based metrics, a procedure that we show to be equivalent to the use of completely homogeneous benchmarks specifying only global constraints. However, this approach does not take into account the heterogeneity in the degree and strength distributions, which is instead a fundamental feature of real-world multiplexes. In this work, we compare the observed dependencies between layers with the expected values obtained from maximum-entropy reference models that appropriately control for the observed heterogeneity in the degree and strength distributions. This information-theoretic approach results in the introduction of novel and improved multiplexity measures that we test on different datasets, i.e. the International Trade Network and the European Airport Network. Our findings confirm that the use of homogeneous benchmarks can lead to misleading results and highlight the important role played by the distribution of hubs across layers.
Mechanisms of biofilm inhibition and degradation by antimicrobial peptides
Authors: Segev-Zarko L. , Saar-Dover Ron , Brumfeld Vlad , Mangoni Maria Luisa , Shai Yechiel 
Published: March 2015

Many bacteria live as biofilms to cope with unfavourable surroundings. Biofilms start from (i) a planktonic stage, (ii) initial adhesion to surfaces and (iii) formation of sessile micro-colonies that secrete extracellular polymeric substance (EPS), leading to bacterial resistance to antibiotics. Antimicrobial peptides (AMPs) are extensively studied with regard to planktonic bacteria but much less so with regard to biofilm formation. In the present study, we investigated how the above three steps are affected by the properties of the AMPs using a series of peptides composed of six lysines and nine leucines, which differ in their sequences and hence their biophysical properties. Treatment with bactericidal peptides at non-inhibitory concentrations resulted in reduced biofilm growth, for some starting from 25 nM which is 0.2 and 0.4% of their minimum inhibitory concentration (MIC 6.3 and 12.5 μM, respectively), continuing in a dose-dependent manner. We suggest that reduced bacterial adhesion to surfaces and decreased biofilm growth are due to the peptide's ability to coat either the biomaterial surface or the bacterium itself. Degradation of established biofilms by bactericidal and non-bactericidal peptides, within 1 h of incubation, occurs by either killing of embedded bacteria or detachment of live ones. In addition to shedding light on the mechanism of biofilm inhibition and degradation, these data may assist in the design of anti-biofilm AMPs.
Speech Recognition Across the Life Span: Longitudinal Changes From Middle-Age to Older Adults
Authors: Dubno Judy R. 
Published: March 2015

Purpose
The purpose of this article is to provide an overview of evidence of age-related declines in speech recognition in middle age to older adulthood; to review contributions of pure-tone thresholds, age, and gender; and to report preliminary results from a longitudinal study.

Method
Pure-tone thresholds and word recognition in quiet and babble are being measured in a large sample of adults yearly or every 2 to 3 years. Analyses included >16,000 audiograms and speech recognition scores from >1,200 adults whose ages ranged from the 40s to the 90s. A multivariable generalized linear repeated mixed model assessed changes in thresholds and speech recognition over time.

Results
Word recognition in quiet declined significantly while controlling for threshold increases, and declines appeared to accelerate near ages 65 to 70 years. Scores for men were poorer than those for women even after controlling for gender differences in thresholds, but rates of decline did not differ by gender. Smaller declines in key word recognition in babble were observed, and declines appeared to accelerate near ages 75 to 80 years.

Conclusions
Additional evidence is needed from large-scale longitudinal cohort studies to determine rates of change of auditory function across the life span. These studies can identify associations with modifiable risk factors and potential mechanisms to reduce, to prevent, or to delay the onset of age-related hearing loss.
Chip implementation of high‐efficient light‐emitting diode dimming driver for high‐power light‐emitting diode lighting system
Authors: Hsia Shih‐Chang , Sheu Ming‐Hwa , Lai Sheng‐Yueh 
Published: March 2015

This study presents a novel high‐power light‐emitting diode (LED) driver based on chip‐level design. We propose a multi‐level current approach to LED dimming, rather than pulsed current. The LED driving current can be controlled directly using a digital interface, making it more user‐friendly. An analysis of output impedance and driving current demonstrates how the driver can be realised on a single chip. A prototype chip was designed using the second generation TSMC 0.25 μm high‐voltage technology. The chip area, including I/O pads and power driver, is only 0.89 mm2. The proposed chip is able to drive a 60 W LED panel at maximum output by regulating current in 16 steps for LED dimming. Measurement results indicate that driving efficiency reaches 96% and lighting efficiency is 20% higher than that achieved using pulsed‐width modulation. Furthermore, the proposed chip is able to reduce interference, improve lighting efficiency, and prolong the lifespan of LED devices.
Agricultural Production under Climate Change: The Potential Impacts of Shifting Regional Water Balances in the United States
Authors: Marshall Elizabeth , Aillery Marcel , Malcolm Scott , Williams Ryan 
Published: March 2015

AbstractGeneral circulation models predict significant and accelerating changes in local patterns of precipitation and temperature during the twenty‐first century. Agriculture's vulnerability to climate change will depend on both the biophysical impacts of climate change on crop yields and on the agricultural system's ability to adapt to changing production conditions. Shifts in the extent and distribution of irrigated and dryland production are a potentially important adaptation response. Farmer flexibility to adapt may be limited, however, by changes in the availability of irrigation water under future climate conditions. This study uses a suite of models to explore the biophysical and economic impacts of climate change on U.S. fieldcrop production under several potential future climate projections, and to explore the potential limits and opportunities for adaptation arising from shifting regional water balances. The study findings suggest that, while irrigation shortages attributable to climate change have varying effects on cropland use, the aggregate impacts on national production are small relative to the direct biophysical impacts of climate change on yield.
A generalized model for longitudinal short- and long-term mortality data for commercial fishery discards and recreational fishery catch-and-releases
Authors: Benoît Hugues P. , Capizzano Connor W. , Knotek Ryan J. , Rudders David B. , Sulikowski James A. , Dean Micah J. , Hoffman William , Zemeckis Douglas R. , Mandelman John W. 
Published: March 2015

AbstractConservation concerns and new management policies such as the implementation of ecosystem-based approaches to fisheries management are motivating an increasing need for estimates of mortality associated with commercial fishery discards and released fish from recreational fisheries. Traditional containment studies and emerging techniques using electronic tags on fish released to the wild are producing longitudinal mortality-time data from which discard or release mortalities can be estimated, but where there may also be a need to account analytically for other sources of mortality. In this study, we present theoretical and empirical arguments for a parametric mixture-distribution model for discard mortality data. We show, analytically and using case studies for Atlantic cod (Gadus morhua), American plaice (Hippoglossoides platessoides), and winter skate (Leucoraja ocellata), how this model can easily be generalized to incorporate different characteristics of discard mortality data such as distinct capture, post-release and natural mortalities, and delayed mortality onset. In simulations over a range of conditions, the model provided reliable parameter estimates for cases involving both discard and natural mortality. These results support this modelling approach, indicating that it is well suited for data from studies in which fish are released to their natural environment. The model was found to be less reliable in simulations when there was a delay in discard mortality onset, though such an effect appears only in a minority of existing discard mortality studies. Overall, the model provides a flexible framework in which to analyse discard mortality data and to produce reliable scientific advice on discard mortality rates and possibilities for mitigation.
On the oxygen abundances of M 67 stars from the turn-off point through the red giant branch
Authors: Takeda Yoichi , Honda Satoshi 
Published: March 2015

AbstractWith an aim to examine whether the surface oxygen composition suffers any appreciable change due to evolution-induced mixing of nuclear-processed material in the envelope of red giants, abundance determinations for O/Fe/Ni based on the synthetic spectrum-fitting method were performed by using the moderate-dispersion spectra in the 7770–7792 Å region (comprising O i 7771–5, Fe i 7780, and Ni i 7788 lines) for 16 stars of the old open cluster M 67 in various evolutionary stages from the turn-off point through the red giant branch. We could not find any meaningful difference in the oxygen abundances between the non-giant group (Teff &gt; 5000 K) and the red-giant group (Teff &lt; 5000 K), which are almost consistent with each other on average (despite that both have rather large dispersions of a few tenths dex caused by insufficient data quality), though only one giant star (S 1054) appears to show an exceptionally low O abundance and thus needs a more detailed study. This result may suggest that oxygen content in the stellar envelope is hardly affected (or any changes are insignificant) by the mixing of H-burning products in the red giant phase, as far as M 67 stars of low mass (∼ 1.3 M⊙) are concerned, which is consistent with the prediction from the conventional stellar evolution theory of first dredge-up.
Process improvement through economically driven routing of instances
Authors: Bolsinger Manuel , Elsäßer Anna , Helm Caroline , Röglinger Maximilian 
Published: March 2015

Purpose
– Process improvement is a fundamental activity of the business process management (BPM) lifecycle. However, practitioners still lack concrete guidance and adequate objectives for process improvement. Moreover, improvement projects typically tie up considerable amounts of capital and are very risky. Thus, more guidance is needed on how to derive concrete recommendations for process improvement in a goal-oriented manner. The paper aims to discuss these issues.

Design/methodology/approach
– The authors propose a decision model that determines along which paths the instances of a process should be routed to maximize the value contribution of the process. To do so, the decision model requires a process model and a set of historical process instances as inputs.

Findings
– The decision model builds on the idea that only the parameters of the process, i.e., the values according to which it is decided on which path an instance traverses the process, can be modified, without altering the structure of the process. The decision model determines the parameter setting that maximizes the value contribution of the process, which is measured in terms of the expected cash flow of the process. When determining the optimal parameter setting, the decision model considers that different instances and paths have different cash flow effects.

Practical implications
– The authors prototypically implemented the decision model and report on the insights from a demonstration example that is based on the order verification process of an IT distributor.

Originality/value
– The decision model complements existing approaches to process improvement as it reveals additional improvement potential by focussing on the decision points in a process without altering the structure of the process. The decision model also enables identifying an optimal parameter setting, as a concrete recommendation for process improvement, in line with the principles of value-based BPM.
Process performance measurement system – towards a customer-oriented solution
Authors: Wieland Uwe , Fischer Marco , Pfitzner Marcus , Hilbert Andreas 
Published: March 2015

Purpose– Based on a systematic literature review, requirements on a PPMS are identified in order to derive concrete demands and design features for such a system by using quality function deployment (QFD). The purpose of this paper is to formulate a proposal for design recommendations toward a holistic, customer-oriented Process Performance Measurement System (PPMS).Design/methodology/approach– A literature review is used to identify customer demands and design features that characterize a PPMS. To determine the critical design features of a customer-oriented solution, the QFD method is applied.Findings– The paper confirms that there is currently no published concept for an integrated, holistic PPMS. Therefore it provides a first approach to the formulation of a design recommendation based on the customer requirements and design features. A literature-based weighting facilitates a first identification of critical design features. The identified conditions specify the context which can be regarded as a prerequisite for the application of the system.Research limitations/implications– As a result of the investigation, two main issues were identified, which restrict the complete development of a House-of-Quality matrix and therefore require further research: First, no reliable relationships between the customer requirements and design features could be derived from the conducted content analysis and second, no correlations between the identified design features could be detected.Practical implications– The paper provides a design basis for specific application systems and their information requirement analyses. It can also serve as an evaluation basis for existing software products in the market.Originality/value– The connection of a literature review with the QFD procedure transfers a consolidated state of PPMS research into an applicable design recommendation and therefore supports rigor and relevance of the research.
Linking operations strategy to the corporate strategy process: a practice perspective
Authors: Adamides Emmanuel D. 
Published: March 2015

Purpose– The purpose of this paper is to provide a micro-level, human-activity-centred interpretative framework for the way operations strategy is formed, linked and aligned with corporate-level strategies, and to apply it to gain insights on these processes.Design/methodology/approach– Relying on the theoretical foundations of social practice theory and actor-network theory, as well as on the analysis of the organisational realities of the operations strategy formation process embedded in pluralistic organisational contexts, a conceptual framework for analysing the production and alignment of operations strategy is developed. The framework is then used to guide field research for the analysis of an operations-led strategic initiative in a medium-sized agro-food company.Findings– Operations strategy formation can be interpreted as an ongoing practical, distributed social activity of network (re)formation. Specific initiatives, or events, act as catalysts for the association of operations strategy formation practices with corporate-level ones, facilitating thus the current and future alignment of strategic content. Artefacts play an active role in the linking process.Research limitations/implications– The research presented in this paper is pioneering as it is the first explicit consideration of operations strategy formation (process) as practical social activity (practices are the focus of analysis, not individuals’ choices), in which non-human agency (informational artefacts, etc.) is explicitly taken into account. For this purpose, a novel analytic framework was developed, which, however, need to be further tested to determine the exact conditions under which it is valid.Practical implications– The framework improves the understanding of the organisational dynamics of operations strategy formation, its linking with, and institutionalisation in, other organisational processes and strategic discourses. Thus, it can assist in the analysis of operations-led strategic initiatives.Social implications– Application of the results obtained can provide better workplaces.Originality/value– For the first time: operations strategy formation is considered as a social activity by focusing on the strategists and managers’ practices; the role of documents, decision-support tools and other artefacts is surfaced; and the importance of introducing operations strategy formation practices carrying strategy content into corporate and business-level strategy processes and their role in the alignment of the two strategies is emphasised.
Do institutions matter in Latin America?
Authors: Kallas David , Caldeira Carlos A. , Bandeira-de-mello Rodrigo , Marcon Rosilene 
Published: March 2015

Purpose– The purpose of this paper is to analyse the effects of institutional changes on business landscapes and companies performance in Brazil.Design/methodology/approach– The authors have developed a multiple empirical strategy, including qualitative and quantitative methods. As a qualitative method, we used business landscapes to describe how clustered firm performance varies across industries. We collected return on equity (ROE) and equity data from Brazilian listed companies in a 24-years range, and compared three different 8-years institutional periods. As a quantitative method, the authors compared variance across periods and developed a panel analysis assuming fixed and random effects models.Findings– The main results indicate that ROE differences among institutional periods in Brazil are relevant, indicating that there is an important institutional effect on performance and the impacts of those institutional effects may be different across industries. The impact of institutional changes seems to be considerable in understanding industry and firm performance. In addition, the improvement of the institutional framework increases the variance of firm performance around the mean.Research limitations/implications– The limitations are related to the sample, classification treatment for missing values and outliers.Practical implications– Managers should consider that institutional settings affect industries in a different manner when developing their strategies.Originality/value– Despite the fact that the importance of industry, firm and time effects has been empirically examined, there is still an empirical gap concerning if and how institutional changes affect industries and the configuration of business landscapes.
Cross-market dynamics and optimal portfolio strategies in Latin American equity markets
Authors: Arouri Mohamed El Hédi , Lahiani Amine , Nguyen Duc Khuong 
Published: March 2015

Purpose
– This paper aims to investigate the return links and volatility transmission between five major equity markets of the Latin American region and the USA over the period 1993-2012.

Design/methodology/approach
– The authors employ a multivariate vector autoregressive moving average – generalized autoregressive conditional heteroskedasticity (VAR-GARCH) methodology which allows for cross-market transmissions in both return and volatility. Moreover, we show how the obtained results can be used to design internationally diversified portfolios involving the Latin American assets and to analyze the effectiveness of hedging strategies.

Findings
– The results point to the existence of substantial cross-market return and volatility spillovers and are thus crucial for international portfolio management in the Latin American region. However, the intensity of shock and volatility cross effects varies across the studied markets.

Research limitations/implications
– The optimal weights and hedging ratios that we compute from the observed return and volatility spillovers, suggest that adding the Latin American assets helps improve the risk-adjusted return of the internationally diversified portfolios as well as reduce their risk exposure. For policymakers and market authorities, an increase in the level of shock interactions and volatility transmission between the US and Latin American equity markets as well as among these Latin American markets implies that the stability of the financial system in one country can be deeply affected by the disturbances in another country.

Originality/value
– The authors extend the previous works on Latin American emerging markets by examining the extent of shock and volatility transmission as well as portfolio design and management from the point of view of both the US (global) and Latin American investors.