bluuebunny/crossref_metadata_2025 huggingface dataset:
Glass transition in single poly(ethylene oxide) chain: A molecular dynamics simulation study
Authors: Wu Chaofu
Published: October 2016

Local dynamics of single poly(ethylene oxide) chain in various environments (bulk, film, and isolated systems) has been characterized by the reorientation functions of various backbone bond vectors. Within any observation time, the variations of these reorientation functions with the temperature can be well described by the Kohlrausch−Williams−Watts (KWW) like equation, in which the fitted temperature parameter is identified as the glass transition temperature (Tg). The so‐obtained Tg for that polymer faithfully reveals the effects of the observation time, chain flexibility and vector range on the local dynamics. Furthermore, it is found that the KWW like relation is also applicable to the temperature‐dependence of the fraction of frozen atoms or torsions defined by the trajectory radii of gyration or the conformational transitions. Consequently, different motions lead to different values of Tg for the same system. Despite all, the consistent trend can be yielded, namely, Tg (bulk) > Tg (film) > Tg (isolated), which captures the effects of free surfaces on enhanced dynamics. In addition, dynamics heterogeneity in the systems can be quantitatively revealed. The newly proposed method holds a bright promise to predict the Tg values of complex polymers especially for comparisons. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017, 55, 178–188
Improving anxiety regulation in patients with breast cancer at the beginning of the survivorship period: a randomized clinical trial comparing the benefits of single‐component and multiple‐component group interventions
Authors: Merckaert Isabelle , Lewis Florence , Delevallez France , Herman Sophie , Caillier Marie , Delvaux Nicole , Libert Yves , Liénard Aurore , Nogaret Jean‐Marie , Ogez David , Scalliet Pierre , Slachmuylder Jean‐Louis , Van Houtte Paul , Razavi Darius
Published: October 2016

Objective

To compare in a multicenter randomized controlled trial the benefits in terms of anxiety regulation of a 15‐session single‐component group intervention (SGI) based on support with those of a 15‐session multiple‐component structured manualized group intervention (MGI) combining support with cognitive‐behavioral and hypnosis components.

Methods

Patients with nonmetastatic breast cancer were randomly assigned at the beginning of the survivorship period to the SGI (n = 83) or MGI (n = 87). Anxiety regulation was assessed, before and after group interventions, through an anxiety regulation task designed to assess their ability to regulate anxiety psychologically (anxiety levels) and physiologically (heart rates). Questionnaires were used to assess psychological distress, everyday anxiety regulation, and fear of recurrence. Group allocation was computer generated and concealed till baseline completion.

Results

Compared with patients in the SGI group (n = 77), patients attending the MGI group (n = 82) showed significantly reduced anxiety after a self‐relaxation exercise (P = .006) and after exposure to anxiety triggers (P = .013) and reduced heart rates at different time points throughout the task (P = .001 to P = .047). The MGI participants also reported better everyday anxiety regulation (P = .005), greater use of fear of recurrence–related coping strategies (P = .022), and greater reduction in fear of recurrence–related psychological distress (P = .017) compared with the SGI group.

Conclusions

This study shows that an MGI combining support with cognitive‐behavioral techniques and hypnosis is more effective than an SGI based only on support in improving anxiety regulation in patients with breast cancer.
Structure of the SLC4 transporter Bor1p in an inward‐facing conformation
Authors: Coudray Nicolas , L. Seyler Sean , Lasala Ralph , Zhang Zhening , Clark Kathy M. , Dumont Mark E. , Rohou Alexis , Beckstein Oliver , Stokes David L.
Published: October 2016

Bor1p is a secondary transporter in yeast that is responsible for boron transport. Bor1p belongs to the SLC4 family which controls bicarbonate exchange and pH regulation in animals as well as borate uptake in plants. The SLC4 family is more distantly related to members of the Amino acid‐Polyamine‐organoCation (APC) superfamily, which includes well studied transporters such as LeuT, Mhp1, AdiC, vSGLT, UraA, SLC26Dg. Their mechanism generally involves relative movements of two domains: a core domain that binds substrate and a gate domain that in many cases mediates dimerization. To shed light on conformational changes governing transport by the SLC4 family, we grew helical membrane crystals of Bor1p from Saccharomyces mikatae and determined a structure at ∼6 Å resolution using cryo‐electron microscopy. To evaluate the conformation of Bor1p in these crystals, a homology model was built based on the related anion exchanger from red blood cells (AE1). This homology model was fitted to the cryo‐EM density map using the Molecular Dynamics (MD) Flexible Fitting method and then relaxed by all‐atom MD simulation in explicit solvent and membrane. Mapping of water accessibility indicates that the resulting structure represents an inward‐facing conformation. Comparisons of the resulting Bor1p model with the X‐ray structure of AE1 in an outward‐facing conformation, together with MD simulations of inward‐facing and outward‐facing Bor1p models, suggest rigid body movements of the core domain relative to the gate domain. These movements are consistent with the rocking‐bundle transport mechanism described for other members of the APC superfamily.
Phosphorylation of KLHL3 at serine 433 impairs its interaction with the acidic motif of WNK4: a molecular dynamics study
Authors: Wang Lingyun , Peng Ji‐Bin
Published: October 2016

Interaction between the acidic motif (AM) of protein kinase WNK4 and the Kelch domain of KLHL3 are involved in the pathogenesis of pseudohypoaldosteronism type II, a hereditary form of hypertension. This interaction is disrupted by some disease‐causing mutations in either WNK4 or KLHL3, or by angiotensin II‐ and insulin‐induced phosphorylation of KLHL3 at serine 433, which is also a site frequently mutated in patients. However, the mechanism by which this phosphorylation disrupts the interaction is unclear. In this study, we approached this problem using molecular dynamics simulation with structural, dynamical and energetic analyses. Results from independent simulations indicate that when S433 was phosphorylated, the electrostatic potential became more negative in the AM binding site of KLHL3 and therefore was unfavorable for binding with the negatively charged AM. In addition, the intermolecular hydrogen bond network that kept the AM stable in the binding site of KLHL3 was disrupted, and the forces for the hydrophobic interactions between the AM of WNK4 and KLHL3 were also reduced. As a result, the weakened interactions were no longer capable of holding the AM of WNK4 at its binding site in KLHL3. In conclusion, phosphorylation of KLHL3 at S433 disrupts the hydrogen bonds, hydrophobic and electrostatic interactions between the Kelch domain of KLHL3 and the AM of WNK4. This study provides a key molecular understanding of the KLHL3‐mediated regulation of WNK4, which is an integrative regulator of electrolyte homeostasis and blood pressure regulation in the kidney.

Significances Statement: WNK4 is an integrative regulator of electrolyte homeostasis, which is important in the blood pressure regulation by the kidney. Interaction between WNK4 and KLHL3 is a key physiological process that is impaired in a hereditary form of hypertension. This study provides substantial new insights into the role of phosphorylation of KLHL3 in regulating the interaction with WNK4, and therefore advances our understanding of molecular pathogenesis of hypertension and the mechanism of blood pressure regulation.
High‐accuracy modeling of antibody structures by a search for minimum‐energy recombination of backbone fragments
Authors: Norn Christoffer H. , Lapidoth Gideon , Fleishman Sarel J.
Published: October 2016

Current methods for antibody structure prediction rely on sequence homology to known structures. Although this strategy often yields accurate predictions, models can be stereo‐chemically strained. Here, we present a fully automated algorithm, called AbPredict, that disregards sequence homology, and instead uses a Monte Carlo search for low‐energy conformations built from backbone segments and rigid‐body orientations that appear in antibody molecular structures. We find cases where AbPredict selects accurate loop templates with sequence identity as low as 10%, whereas the template of highest sequence identity diverges substantially from the query's conformation. Accordingly, in several cases reported in the recent Antibody Modeling Assessment benchmark, AbPredict models were more accurate than those from any participant, and the models' stereo‐chemical quality was consistently high. Furthermore, in two blind cases provided to us by crystallographers prior to structure determination, the method achieved <1.5 Ångstrom overall backbone accuracy. Accurate modeling of unstrained antibody structures will enable design and engineering of improved binders for biomedical research directly from sequence. Proteins 2016; 85:30–38. © 2016 Wiley Periodicals, Inc.
Performance of ZDOCK and IRAD in CAPRI rounds 28–34
Authors: Vreven Thom , Pierce Brian G. , Borrman Tyler M. , Weng Zhiping
Published: October 2016

We report the performance of our protein–protein docking pipeline, including the ZDOCK rigid‐body docking algorithm, on 19 targets in CAPRI rounds 28‐34. Following the docking step, we reranked the ZDOCK predictions using the IRAD scoring function, pruned redundant predictions, performed energy landscape analysis, and utilized our interface prediction approach RCF. In addition, we applied constraints to the search space based on biological information that we culled from the literature, which increased the chance of making a correct prediction. For all but two targets we were able to find and apply biological information and we found the information to be highly accurate, indicating that effective incorporation of biological information is an important component for protein–protein docking. Proteins 2017; 85:408–416. © 2016 Wiley Periodicals, Inc.
Combined use of Bacillus subtilis strain B‐001 and bactericide for the control of tomato bacterial wilt
Authors: Peng Di , Luo Kun , Jiang Huidan , Deng Yanan , Bai Lianyang , Zhou Xiaomao
Published: October 2016

BACKGROUND

Tomato bacterial wilt caused by Ralstonia solanacearum poses a serious threat to tomato production. However, no effective control measures are available. In this study, the bactericide Saisentong was combined with an effective biological control agent, Bacillus subtilis B‐001, to control tomato bacterial wilt under greenhouse and field conditions.

RESULTS

Growth of B‐001 in vitro was unaffected by Saisentong. In greenhouse experiments, the combined application of B‐001 and Saisentong via root irrigation or spray resulted in better disease control compared with either agent alone. In two field trials, at a Saisentong concentration of 400 or 500 mg kg−1, the combined treatment was more effective than expected and showed a synergistic effect. A lower concentration of Saisentong (200 or 300 mg kg−1) in combination with B‐001 resulted in an antagonistic effect. However, disease control was significantly greater compared with either treatment alone.

CONCLUSION

The combination of Saisentong and B‐001 effectively controls tomato bacterial wilt. The integrated strategy represents a promising new tool to control this disease. © 2016 Society of Chemical Industry
Enhanced supercapacitance of vertically aligned multi‐wall carbon nanotube array covered by MoS2 nanoparticles
Authors: Koroteev V. O. , Kuznetsova I. V. , Kurenya A. G. , Kanygin M. A. , Fedorovskaya E. O. , Mikhlin Y. L. , Chuvilin A. L. , Bulusheva L. G. , Okotrub A. V.
Published: October 2016

Vertically aligned multi‐wall carbon nanotube (VA‐MWCNT) arrays have been used for deposition of molybdenum sulphide from a water solution of ammonia molybdate and thiourea. A hydrothermal synthesis at 175 °C resulted in formation of quasi‐spherical nanoparticles inside and on the top surface of arrays without destruction of the array structure. X‐ray photoelectron spectroscopy revealed a molybdenum disulfide (MoS2) composition of the nanoparticles, while Raman spectroscopy detected the bands characteristic of light scattering in the MoS2 crystallites only after a treatment of synthesis products in hydrogen flow. As compared to the initial VA‐MWCNTs, the composites showed enhanced specific capacitances in 1M H2SO4 electrolyte especially at low scan rates due to redox reactions involving MoS2. The reactions were more pronounced for the hydrogen treated composite.

Cyclic voltammetry curves demonstrate an enhanced specific capacitance of MoS2/MWCNT array (fragment of the structure is shown in the insert) as compared to initial array due to redox reactions.
Photoelectric and photoluminescence properties of CdTe–GaTe composite
Authors: Caraman Iuliana , Spalatu Nicolae , Evtodiev Igor , Untila Dumitru , Leontie Liviu , Caraman Mihail
Published: October 2016

A GaTe–CdTe composite was obtained by thermal treatment at 1020 K of GaTe single crystals in Cd vapor atmosphere. The composite photoluminescence, photoconductivity, and composition are studied in this work. The photosensitivity and photoluminescence band structure are determined for both the primary crystals and the composite. The CdTe crystallites create, in the GaTe bandgap, recombination and trapping levels, which determine the structure of the photoluminescence spectra and the spectral range of composite photosensitivity. The photoluminescence spectrum of the composite at 80 K contains characteristic bands of both composite components, GaTe and CdTe. From the analysis of thermally stimulated luminescence curves, the energies of the electron trapping levels in the composite are determined.
Historical ocean reanalyses (1900–2010) using different data assimilation strategies
Authors: Yang Chunxue , Masina Simona , Storto Andrea
Published: October 2016

Two historical ocean reanalyses that cover the period from 1900 to 2010 are performed. One ocean reanalysis (CHOR_AS) assimilates both sea‐surface temperature (SST) and vertical profile data with a 3D‐Var assimilation scheme, while the other one (CHOR_RL) assimilates vertical profile data, but is nudged to monthly Hadley Centre global sea Ice coverage and SST (HadISST) reconstructed fields. The reanalyses are thus designed to investigate the impact of different strategies for constraining the SST in long‐term assimilation experiments and the feasibility of assimilating subsurface observations in the same kind of experiments. The atmospheric forcing comes from the ensemble mean of the Twentieth‐Century Reanalysis version 2 (20CRv2). Due to biases being particularly large at high latitudes, corrections are applied to the atmospheric forcing, based on the comparison with ECMWF's ERA‐Interim during the overlapped period. In general, these ocean reanalyses capture trends and variability of key ocean parameters. A warm bias of SST in CHOR_AS in the first half of the century leads to incorrect long‐term trends. However, SST anomalies in both CHOR_AS and CHOR_RL are realistically captured. Heat contents at 0–300, 0–700 and 0–2000 m have an increasing trend in both CHOR_RL and CHOR_AS, consistent with available datasets for the second half of the century. In order to reproduce realistic mass transport, mixed‐layer depth and eddy kinetic energy, it is necessary to assimilate vertical profile data, although this leads to some discontinuities in the reanalysis time series. Based on these findings, we suggest ideas for the requirements of future historical ocean reanalyses, such as related to the necessity of applying bias correction and minimizing the effects of the observing network discontinuities. Meanwhile, the comparison between CHOR_RL and CHOR_AS shows that both direct assimilation and the nudging scheme have their advantages and disadvantages. A combination of these two schemes is desirable in future work.
The non‐local character of turbulence asymmetry in the convective atmospheric boundary layer
Authors: Ghannam Khaled , Duman Tomer , Salesky Scott T. , Chamecki Marcelo , Katul Gabriel
Published: October 2016

The inadequacy of conventional gradient diffusion in closure modelling of turbulent heat fluxes within the convective atmospheric boundary layer is often alleviated by accounting for non‐local transport effects, such as Deardorff's counter‐gradient models, Wyngaard's transport asymmetry closures or mass‐flux parametrization. This concept of large‐eddy flux transport is examined here with the principal aim of unifying these seemingly different models. Using large‐eddy simulation (LES) runs for the atmospheric boundary layer, spanning weakly to strongly convective conditions, a generic diagnostic framework that encodes the role of third‐order moments in non‐local transport is developed and tested. The premise is that these non‐local effects are responsible for the inherent asymmetry in vertical transport and hence the necessary non‐Gaussian nature of the joint probability density function (JPDF) of vertical velocity and potential temperature must account for these effects. Conditional sampling (quadrant analysis) of this JPDF and the imbalance between the flow mechanisms of ejections and sweeps are used to characterize this asymmetry, which is then linked to the third‐order moments using a cumulant‐discard method for the Gram–Charlier expansion of the JPDF. While the concept of ejection‐sweep events used here is not a simple extension of that commonly used in the surface layer, their connection to third‐order moments shows that the concepts of bottom‐up/top‐down diffusion or updraught/downdraught models are accounted for by various quadrants of the JPDF. An analogy between mass‐flux models and the relaxed eddy accumulation method reveals that there is a seemingly implicit assumption of a Gaussian JPDF in the former.
The development and error analysis of a kinematic parameters based spatial positioning method for an orthopedic navigation robot system
Authors: Pei Baoqing , Zhu Gang , Wang Yu , Qiao Huiting , Chen Xiangqian , Wang Binbin , Li Xiaoyun , Zhang Weijun , Liu Wenyong , Fan Yubo
Published: October 2016

Background

Spatial positioning is the key function of a surgical navigation robot system, and accuracy is the most important performance index of such a system.

Methods

The kinematic parameters of a six degrees of freedom (DOF) robot arm were used to form the transformation from intraoperative fluoroscopy images to a robot's coordinate system without C‐arm calibration and to solve the redundant DOF problem. The influences of three typical error sources and their combination on the final navigation error were investigated through Monte Carlo simulation.

Results

The navigation error of the proposed method is less than 0.6 mm, and the feasibility was verified through cadaver experiments. Error analysis suggests that the robot kinematic error has a linear relationship with final navigation error, while the image error and gauge error have nonlinear influences.

Conclusions

This kinematic parameters based method can provide accurate and convenient navigation for orthopedic surgeries. The result of error analysis will help error design and assignment for surgical robots.
Heterogeneous consensus of higher‐order multi‐agent systems with mismatched uncertainties using sliding mode control
Authors: Mondal Sanjoy , Su Rong , Xie Lihua
Published: October 2016

A robust consensus controller is proposed for heterogeneous higher‐order nonlinear multi‐agent systems, when the agent dynamics are involved with mismatched uncertainties. A distributed consensus protocol based on a time‐varying nonhomogeneous finite‐time disturbance observer and sliding mode control is designed to realize the network consensus of higher‐order multi‐agent systems. The time‐varying finite‐time disturbance observer overcomes the problem of peaking value near the initial time caused by the constant gain one and is designed to estimate the uncertainties and to mitigate the effect of mismatched uncertainties during the sliding mode. To eliminate the chattering phenomenon and ensure finite‐time convergence to the sliding surface, the control law is designed by using the super twisting algorithm. Finally numerical simulations are given to illustrate the validity of the proposed method. Copyright © 2016 John Wiley & Sons, Ltd.
Impulsive positive observers and dynamic output feedback stabilization of positive linear continuous systems
Authors: Xiao Jiang‐Wen , Hu Meng‐Jie , Wang Yan‐Wu , Chen Wu‐Hua
Published: October 2016

This paper is concerned with the design and the synthesis of the impulsive positive observer (IPO) for positive linear continuous systems. The IPO can estimate the states for positive systems even when the measured output is only available at discrete‐time instants. In this paper, a time‐varying weighted copositive Lyapunov function is constructed, and the upper and lower bounds of impulsive intervals method combined with the convex combination technique are used to establish sufficient conditions for the existence of the IPO. Furthermore, the design of the dynamic output feedback controller based on the IPO is addressed to positively stabilize positive linear systems. Algorithms are given to design the IPO and the controller, respectively. Finally, two numerical examples are provided to show the effectiveness of the theoretical results. Copyright © 2016 John Wiley & Sons, Ltd.
Models for zero‐inflated, correlated count data with extra heterogeneity: when is it too complex?
Authors: Chebon Sammy , Faes Christel , Cools Frank , Geys Helena
Published: October 2016

Statistical analysis of count data typically starts with a Poisson regression. However, in many real‐life applications, it is observed that the variation in the counts is larger than the mean, and one needs to deal with the problem of overdispersion in the counts. Several factors may contribute to overdispersion: (1) unobserved heterogeneity due to missing covariates, (2) correlation between observations (such as in longitudinal studies), and (3) the occurrence of many zeros (more than expected from the Poisson distribution). In this paper, we discuss a model that allows one to explicitly take each of these factors into consideration. The aim of this paper is twofold: (1) investigate whether we can identify the cause of overdispersion via model selection, and (2) investigate the impact of a misspecification of the model on the power of a covariate. The paper is motivated by a study of the occurrence of drug‐induced arrhythmia in beagle dogs based on electrocardiogram recordings, with the objective to evaluate the effect of potential drugs on the heartbeat irregularities. Copyright © 2016 John Wiley & Sons, Ltd.
The importance of provision and utilization of supervisor support
Authors: Munc Alec , Eschleman Kevin , Donnelly Janet
Published: October 2016

Three cross‐sectional studies examined the benefits of provision of supervisor support while controlling for subordinate utilization of supervisor support. Data were collected from workers in a subordinate role (Study 1 N = 355; Study 2 N = 229; Study 3 N = 109). Consistent with expectations, provision of supervisor support consistently explained unique variance in affective job criteria while controlling for utilization of supervisor support. The results indicate that supervisors should acknowledge that their workers experience the affective benefits of supervisor support even if the workers do not consistently use the support provided. Contrary to expectations, provision of supervisor support did not consistently explain unique variance in perceived job stressors while controlling for utilization of supervisor support. However, workers must utilize the supervisor support provided in order to perceive fewer job stressors. We recommend supervisors to take caution when relocating their support to different subordinates based solely on a lack of utilization of support, as this may cause higher perceived job stressors for their subordinates based on the lack of provision of that support.
Emotional contagion and burnout among nurses and doctors: Do joy and anger from different sources of stakeholders matter?
Authors: Petitta Laura , Jiang Lixin , Härtel Charmine E.J.
Published: October 2016

The present study adds novel knowledge to the literature on emotional contagion (EC), discrete emotions, job burnout, and the management of healthcare professionals by simultaneously considering EC as both a job demand and a job resource with multiple social pathways. Integrating EC into the job demands‐resource model, we develop and test a conceptual model wherein multiple stakeholder sources of emotional exchanges (i.e., leaders, colleagues, patients) play a differential role in predicting caregivers' absorption of positive (i.e., joy) and negative (i.e., anger) emotions, and in turn, burnout. We tested this nomological network using structural equation modeling and invariance analyses on a sample of 252 nurses and 102 doctors from diverse healthcare wards in three Italian hospitals. Our findings show that not all emotional exchange sources contribute to the EC experience or likelihood of burnout. Specifically, we found that doctors absorbed joy and anger from their colleagues but not from their leaders or patients. In contrast, nurses absorbed joy and anger from leaders, colleagues, and patients. Surprisingly, we found that joy‐absorbed and anger‐absorbed were related to doctors' exhaustion and cynicism, but only to nurses' cynicism. We conclude with suggestions for advancing research and practice in the management of emotions for preventing burnout.
Nonmarket strategy research through the lens of new institutional economics: An integrative review and future directions
Authors: Dorobantu Sinziana , Kaul Aseem , Zelner Bennet
Published: October 2016

Research summary:We use a novel theoretical framework to synthesize ostensibly disparate streams of nonmarket strategy research. We argue that faced with weak institutions, firms can create and appropriate value by either adapting to, augmenting, or transforming the existing institutional environment, and can do so either independently or in collaboration with others. We use the resulting typology of six distinct nonmarket strategies to provide an integrative review of nonmarket strategy research. We then extend this framework to examine the choice between nonmarket strategies, arguing that this choice depends upon whether the existing institutional environment is incomplete or captured, and discussing other drivers of nonmarket strategy choice, the relationship between these strategies, and their social impact, so as to provide an agenda for future research.

Managerial summary:The pursuit of competitive advantage often requires firms to operate in contexts where existing rules and regulations provide inadequate protection. Disruptive technologies open up new opportunities for value creation, but it takes years before appropriate regulations are introduced. Economic reforms open up new markets, but these are often regulated to favor incumbents and politically connected insiders. In such environments, managers must decide whether to adapt their strategies to the existing institutional environment, devote resources to improve it, or try to transform it altogether. In this article, we develop an integrative theoretical framework that connects and synthesizes research examining each of these options, and offers some preliminary thoughts on how managers may choose among these different approaches. Copyright © 2016 John Wiley & Sons, Ltd.
Categories and competition
Authors: Cattani Gino , Porac Joseph F. , Thomas Howard
Published: October 2016

Research summary: In this article, we review, integrate, and extend the literature on markets, competition, and categories as it applies to strategic management theory. Developments in the literatures of economics and organizational theory have shed new light on market categories and category dynamics. These developments highlight the fact that boundary questions are fundamental to the competitive process, and represent a fertile area for research and theory. The objective is to encourage a theoretically grounded rapprochement between current strategic management research and both older and newer research on categories and competition.

Managerial summary: One of the key problems for business strategists is understanding the competitive environment and interpreting the effects of competition on a business. This article attempts to integrate various literatures in the study of competition by suggesting that strategists play a crucial role in linking abstract categories of firms and products that have become part of an industry's terminology with real‐time competitive processes taking place among firms and buyers. Strategists interpret cues such as cross‐elasticities of demand among their own and competing products and connect these cues to taken‐for‐granted categories demarcating the boundaries of markets. Simultaneously, strategists are introducing new categories by reformulating old nomenclatures and introducing new ones. We also trace the possible effects of this ‘competitive sensemaking’ on firm behaviors. Copyright © 2016 John Wiley & Sons, Ltd.
Value capture theory: A strategic management review
Authors: Gans Joshua , Ryall Michael D.
Published: October 2016

Research summary: This article provides the first review of a growing line of scholarly work in strategy that we refer to as “value capture theory.” The common thread in this work is its use of cooperative game theory as a general, mathematical foundation upon which to build a deep understanding of firm performance in market settings. Our review: (1) describes the primary elements of the theory; (2) highlights important blindspots that it resolves with respect to existing theoretical approaches; (3) calls attention to several of its novel insights; and (4) summarizes a myriad of applications and empirical studies that have appeared in recent years using value capture theory.

Managerial summary: Traditionally, theoretical claims in strategic management have been supported by informal, qualitative reasoning. Recently, however, a new line of theoretical work based upon mathematical methods, known as “value capture theory,” has been gaining in popularity. This article reviews the recent advances in this line with a particular emphasis upon a number of its important insights, several of which challenge longstanding propositions from the traditional line. For managers, the formal nature of value capture theory is well‐aligned with data‐driven analyses of strategic situations. Copyright © 2016 John Wiley & Sons, Ltd.
Real options theory in strategic management
Authors: Trigeorgis Lenos , Reuer Jeffrey J.
Published: October 2016

Research summary: This article provides a review of real options theory (ROT) in strategic management research. We review the fundamentals of ROT and provide a taxonomy of this research. By synthesizing and critiquing research on real options, we identify a number of important challenges as well as opportunities for ROT if it is to enhance its impact on strategic management and potentially develop into a theoretical pillar in the field. We examine how ROT can inform the key tensions that managers face between commitment versus flexibility as well as between competition versus cooperation, and we show how it can uniquely address the fundamental issues in strategy. We conclude with suggestions on future research directions that could enhance and unify the thus‐far distinct main approaches to real options research.

Managerial summary: Real options theory (ROT) applies the heuristics and valuation models originally designed for financial securities to the domain of corporate investment decisions (e.g., joint ventures [JVs], foreign direct investment, research and development [R&D], etc.) and strategic decision making under uncertainty. This article provides a synthesis of this body of research in strategic management and related disciplines. We suggest how ROT can address fundamental issues of strategy, including the dilemmas managers face between commitment versus flexibility as well as between competition versus cooperation. We discuss how three distinct approaches to real options analysis can complement each other, and we identify some of the main challenges and opportunities for ROT to become a theoretical pillar in strategy. Copyright © 2016 John Wiley & Sons, Ltd.
AmaLgam+: Composing Rich Information Sources for Accurate Bug Localization
Authors: Wang Shaowei , Lo David
Published: October 2016

During the evolution of a software system, a large number of bug reports are submitted. Locating the source code files that need to be fixed to resolve the bugs is a challenging problem. Thus, there is a need for a technique that can automatically figure out these buggy files. A number of bug localization solutions that take in a bug report and output a ranked list of files sorted based on their likelihood to be buggy have been proposed in the literature. However, the accuracy of these tools still needs to be improved. In this paper, to address this need, we propose AmaLgam+, which is a method for locating relevant buggy files that puts together fives sources of information, namely, version history, similar reports, structure, stack traces, and reporter information. We perform a large‐scale experiment on four open source projects, namely, AspectJ, Eclipse, SWT, and ZXing to localize more than 3000 bugs. We compare AmaLgam + with several state‐of‐the‐art approaches including AmaLgam, BLUiR+, BRtracer+, BugLocator, and TFIDF‐DHbPd. These approaches leverage one or several of the sources of information analyzed by AmaLgam+, but not all of them. On average, AmaLgam + achieves a 6.0% improvement over AmaLgam, which merges three sources of information, in terms of Mean Average Precision (MAP). For AspectJ and Eclipse datasets, in which there are many bug reports with stack traces and many reporters submit multiple bug reports, AmaLgam + achieves a 12.0% improvement over AmaLgam in terms of MAP. Compared with the other state‐of‐the‐art approaches, AmaLgam + achieves an improvement of 20.3%, 22.5%, 33.1%, and 73.9% over BLUiR+, BRtracer+, BugLocator, and TFIDF‐DHbPd in terms of MAP, respectively. Copyright © 2016 John Wiley & Sons, Ltd.
Metabolic Reconfiguration Supports Reacquisition of Primitive Phenotype in Human Mesenchymal Stem Cell Aggregates
Authors: Liu Yijun , Muñoz Nathalie , Tsai Ang-Chen , Logan Timothy M. , Ma Teng
Published: October 2016

Spontaneous aggregation and the associated enhancement of stemness have been observed in many anchorage dependent cells. Recently, aggregation of human mesenchymal stem cells (hMSCs) in nonadherent culture has been shown to reverse expansion-induced heterogeneity and loss of stemness and reprogram the hMSC to reacquire their primitive phenotype, a phenomenon that can significantly enhance therapeutic applications of hMSC. The objective of this study was to investigate the mechanistic basis underlying the connection between multicellular aggregation and stemness enhancement in hMSC by testing the hypothesis that cellular events induced during three-dimensional aggregation on nonadherent substratum induces changes in mitochondrial metabolism that promote the expression of stem cell genes Oct4, Sox2, and Nanog. Our results show that aggregation changes mitochondrial morphology and reduces mitochondrial membrane potential, resulting in a metabolic reconfiguration characterized by increased glycolytic and anaplerotic flux, and activation of autophagy. We further demonstrate that interrupting mitochondrial respiration in two-dimensional planar culture with small molecule inhibitors partially recapitulates the aggregation-mediated enhancement in stem cell properties, whereas enhancement of mitochondrial oxidative phosphorylation in the aggregated state reduces the aggregation-induced upregulation of Oct4, Sox2, and Nanog. Our findings demonstrate that aggregation-induced metabolic reconfiguration plays a central role in reacquisition of primitive hMSC phenotypic properties.
Chemokine-Like Receptor 1 Is a Novel Wnt Target Gene that Regulates Mesenchymal Stem Cell Differentiation
Authors: Muruganandan Shanmugam , Govindarajan Rajgopal , McMullen Nichole M. , Sinal Christopher J.
Published: October 2016

Bone remodeling is a dynamic process requiring the coordinated action of formative (osteoblast) and resorptive (osteoclast) cell populations. An imbalance of the development and function of these cell types underlies several chronic bone loss disorders such as osteoporosis. Increased bone marrow adipocyte numbers commonly occur with bone loss disorders and numerous studies have documented an inverse relationship between bone marrow fat and bone formation. Osteoblasts and adipocytes derive in a competitive fashion from a common mesenchymal stem cell (MSC) precursor. Generally, factors that promote MSC adipogenesis inhibit osteoblastogenesis and thereby, reduce bone formation. Previously we established that the secreted protein chemerin regulates adipogenic and osteoblastogenic differentiation of MSCs by signaling through chemokine-like receptor 1 (CMKLR1). However, the fundamental mechanisms by which chemerin/CMKLR1 influences lineage determination remain largely uncharacterized. Herein, we provide experimental evidence that chemerin/CMKLR1 regulates canonical Wnt signaling in MSCs by influencing the expression, subcellular location, and transcriptional activity of the central Wnt transducer, β-catenin. Moreover, we provide evidence that CMKLR1 is a novel Wnt responsive gene that functions in a negative feedback loop to limit osteoblastogenic Wnt signaling. Mechanistically, this entails Notch-dependent changes in the expression and function of key adipogenic and osteoblastogenic transcription factors, cell cycle proteins and chromatin remodeling enzymes. Consistent with this, MSCs from CMKLR1 knockout (−/−) mice exhibited similar dependency on Notch signaling to maintain osteoblastogenic differentiation. Taken together, our findings support a fundamental biological function for chemerin/CMKLR1 to balance osteoblastogenic and adipogenic signaling and thereby contribute to the maintenance of pluripotency in MSCs.
Constitutive Activation of NIK Impairs the Self-Renewal of Hematopoietic Stem/Progenitor Cells and Induces Bone Marrow Failure
Authors: Xiu Yan , Xue Wingel Y. , Lambertz Allyn , Leidinger Mariah , Gibson-Corley Katherine , Zhao Chen
Published: October 2016

Previously we have shown that loss of non-canonical NF-κB signaling impairs self-renewal of hematopoietic stem/progenitor cells (HSPCs). This prompted us to investigate whether persistent activation of the non-canonical NF-κB signaling will have supportive effects on HSPC self-renewal. NF-κB-inducing kinase (NIK) is an important kinase that mainly activates the non-canonical pathway through directly phosphorylating IKKα. In contrast to our expectations, constitutive activation of NIK in the hematopoietic system leads to bone marrow (BM) failure and postnatal lethality due to intrinsic impairment of HSPC self-renewal and extrinsic disruption of BM microenvironment through enhancing osteoclastogenesis. The impaired HSPC function is associated with reduced cell proliferation and increased apoptosis and inflammatory cytokine responses. RNAseq analysis of control and NIK-activated HSPCs reveals that these effects are through non-canonical NF-κB signaling without significant changes in the canonical pathway. Gene set expression analysis of RNAseq data reveals globally decreased stem cell signature, increased maturation signature, and increased inflammatory responses. Many genes (Mpl, Tifab, Emcn, Flt3, Bcl2, and others) that regulate HSPC self-renewal, lineage commitment, and apoptosis are significantly downregulated—and those genes that regulate inflammatory responses and cell cycle inhibition (Cdkn2a and Cdkn2b) are significantly upregulated—by activation of NIK. Importantly, our data demonstrate that activation of NIK-non-canonical signaling has distinct phenotypes—smaller spleen size, decreased white blood cell counts, and reduced HSPC proliferation—compared to activation of canonical signaling. Collectively, these data indicate that the balanced non-canonical NF-κB signaling is essential for maintaining normal hematopoiesis and NIK-non-canonical signaling contributes to the development of BM failure.
Country‐of‐Origin and Social Resistance in Host Countries: The Case of a Chinese Firm
Authors: Yu Yang , Liu Yulong
Published: October 2016

While China's outward direct investments continue to soar, many Chinese firms reportedly face social resistance in host countries during the internationalization process. We explore this phenomenon from a country‐of‐origin (COO) perspective using Fiske and colleagues’ (Fiske, Cuddy, Glick, & Xu, 2002; Fiske, Xu, Cuddy, & Glick, 1999) stereotype content model. Our findings from a recent case in New Zealand show that China's COO emerges as a key variable influencing how local actors view Chinese investors. Specifically, despite China's significant economic and social developments over the past decades, it suffers from a somewhat negative country image in two stereotype dimensions: competence and warmth. This leads to a perception by local actors that Chinese firms are of low quality, which explains the source of resistance in society. To address such a liability of origin, Chinese firms must learn to deal with this form of stereotypical judgment encountered in a host environment. Further contributions and limitations of the study are discussed in the article. © 2016 Wiley Periodicals, Inc.
Pelvic floor muscle dysfunction on 3D/4D transperineal ultrasound in patients with deep infiltrating endometriosis: a pilot study
Authors: Raimondo D. , Youssef A. , Mabrouk M. , Del Forno S. , Martelli V. , Pilu G. , Rizzo N. , Zannoni L. , Paradisi R. , Seracchioli R.
Published: October 2016

Objective

Pelvic floor muscle (PFM) dysfunction seems to play an important role in the pathophysiology of pelvic pain, including that associated with deep infiltrating endometriosis (DIE). The aim of this study was to evaluate the static and dynamic morphometry of the PFM using three‐dimensional (3D) and four‐dimensional (4D) transperineal ultrasound in women with DIE compared with asymptomatic healthy women.

Methods

This was a pilot, prospective study conducted at our tertiary center between March and November 2015. Fifty nulliparous women with DIE (study group) and 35 nulliparous asymptomatic healthy women (control group) were included. 3D/4D transperineal ultrasound examination of the PFM was performed in both groups. Levator hiatal area (LHA) and anteroposterior and left–right transverse diameters were evaluated at rest, on maximum PFM contraction and on maximum Valsalva maneuver. Persistent levator ani muscle (LAM) coactivation during Valsalva maneuver was investigated.

Results

Compared with the control group, women with DIE had a smaller LHA at rest (P = 0.03) and during Valsalva maneuver (P < 0.01). Furthermore, reduction in LHA during PFM contraction (P < 0.001) and enlargement in LHA during Valsalva maneuver (P = 0.01) were significantly less marked. In comparison with controls, women with DIE presented a higher frequency of LAM coactivation during Valsalva maneuver, although this difference did not reach statistical significance (P = 0.05).

Conclusions

3D and 4D transperineal ultrasound is an objective and non‐invasive method for PFM morphometry and may have a role in detecting PFM dysfunction in women with DIE. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.
Effects of non‐rainfall water inputs on ecosystem functions
Authors: Wang Lixin , Kaseke Kudzai F. , Seely Mary K.
Published: October 2016

Non‐rainfall water inputs (NRWIs) are the least studied hydrological components in most ecosystems. These NRWI components potentially play an important role in ecosystem dynamics and are particularly important for water‐limited systems. In this review, we summarized recent advances investigating the effects of NRWIs on various ecosystem functions, including vegetation‐water relations, biogeochemical cycling, groundwater recharge, as well as reptile and invertebrate adaptations. We also identified key knowledge gaps such as the mechanisms of NRWIs alleviating vegetation water stress, sources of the NRWI components and their quantitative contributions to ecosystem functions. To better predict the ecosystem responses to climate change especially in drylands, a better understanding and quantification of NRWI contributions is essential. WIREs Water 2017, 4:e1179. doi: 10.1002/wat2.1179

This article is categorized under:

Water and Life > Nature of Freshwater Ecosystems

Science of Water > Hydrological Processes

Science of Water > Water Extremes
Wildlife monitoring with unmanned aerial vehicles: Quantifying distance to auditory detection
Authors: Scobie Corey A. , Hugenholtz Chris H.
Published: October 2016

There is growing application of small unmanned aerial vehicles (UAVs) for detecting, enumerating, and monitoring wildlife. However, little is known about how the sound from UAVs may be affecting wildlife being studied. We quantified sound levels of 2 UAVs to determine minimum altitudes they can fly before being aurally detected by wildlife. We tested a small quadcopter (SkyRanger; Aeryon Labs, Inc., Waterloo, ON, Canada) and a fixed‐wing platform (eBee; Sensefly Ltd., Cheseaux‐sur‐Lausanne, Vaud, Switzerland) at the University of Calgary in Calgary, Alberta, Canada, between 1000 and 1200 hours on 27 September 2014. We modeled sound propagation and attenuation in relation to the lower hearing thresholds for 3 game species and 2 species of predators. Results indicate that the UAV sound levels differed in the lower frequency ranges, but were otherwise similar above 1.25 kHz. The domestic cat (Felis silvestris catus) has the lowest hearing threshold, with the capacity to hear both UAVs from the furthest distance; whereas, the mallard (Anas platyrhynchos) has the greatest hearing threshold, which means UAVs can be closer before being aurally detected. Because flying height is related to image resolution, our results indicate that the ability to detect some wildlife species may be affected by the need to fly higher to minimize sound disturbance, potentially requiring higher resolution cameras than those currently used. Also, additional flight permitting may be required if modeling indicates a UAV must fly at a greater height to avoid a behavioral response by the target species. © 2016 The Wildlife Society.
The regulatable MAL32 promoter in Saccharomyces cerevisiae: characteristics and tools to facilitate its use
Authors: Meurer Matthias , Chevyreva Veronika , Cerulus Bram , Knop Michael
Published: October 2016

Here we describe a set of tools to facilitate the use of maltose and the MAL32 promoter for regulated gene expression in yeast, alone or in combination with the GAL1 promoter. Using fluorescent protein reporters we find that under non‐inducing conditions the MAL32 promoter exhibits a low basal level of expression, similar to the GAL1 promoter, and that both promoters can be induced independently of each other using the respective sugars, maltose and galactose. While their repression upon glucose addition is immediate and complete, we found that the MAL32 and GAL1 promoters each exhibit distinct induction kinetics. A set of plasmids is available to facilitate the application of the MAL32 promoter for chromosomal modifications using PCR targetting and for plasmid based gene expression. Copyright © 2016 John Wiley & Sons, Ltd.