bluuebunny/crossref_metadata_2025_split huggingface dataset:
Two‐pulse frequency‐hopped excitation
Authors: Michal Carl A. , Dong Ronald Y. 
Published: April 2018

AbstractThe use of frequency‐hopped pulse pairs and pulse pair trains for exciting NMR signals is introduced. Pairs of pulses, each pair lasting one nutation period about the effective field in the rotating frame, can be used to efficiently tip nuclear spin magnetization. In the limit where the frequency difference between the partners in a pair is large, the magnetization dynamics mimic those of an ordinary rectangular rf pulse with rf amplitude scaled down by a factor of π/2. When the amplitude of the applied rf begins to approach the offset frequency however, the excitation bandwidth broadens dramatically in a manner reminiscent of a composite pulse. The effects of the frequency‐hopped pulse pairs is described with analytical calculations and numerical simulations, and are shown to agree well with experiment.
A tribute to Alexander Davidson Bain: An NMR pioneer and mentor at McMaster University
Authors: Anand Christopher , Berno Bob , Boulton Stephen , Brook Michael A. , Epand Richard , Field Timothy R. , Goward Gillian R. , Hazendonk Paul , Melacini Giuseppe 
Published: April 2018

AbstractIn this tribute to our friend, mentor and colleague Alexander Davidson Bain we have collectively recapitulated the milestones of his career at McMaster university. We start from Alex's scientific and educational achievements and continue with his accomplishments as a community and infrastructure builder. We attempt to provide a sense of the breadth and depth of his seemingly endless scientific contributions while at McMaster by briefly summarizing selected representative examples from his body of work. Following Alex's lead, the scientific account is mixed with anecdotes and “bits of wisdom” we fondly remember from our interactions and collaborations with him. We also touch upon his brilliant and nurturing educational style and his “aggregator” role within the McMaster and wider NMR communities. We conclude with a more personal picture of Alex D. Bain, in which his scientific excellence and profound intellect are inextricably tied to his kind, nurturing and optimistic character and to his uniquely wry humor. He was not just a “good guy,” he was the epitome of the “good guy.”
Dependence of electron paramagnetic resonance spectral lineshapes on molecular tumbling: Nitroxide radical in water:glycerol mixtures
Authors: Clark Ashley , Sedhom Jessica , Elajaili Hanan , Eaton Gareth R. , Eaton Sandra S. 
Published: April 2018

AbstractElectron paramagnetic resonance spectra of nitroxide radicals are reporters of molecular tumbling correlation times. The concepts of electron paramagnetic resonance and molecular tumbling are demonstrated by examination of spectra of the radical tempol (4‐hydroxy‐2,2,6,6‐tetramethylpiperidin‐1‐oxyl) in water:glycerol mixtures. Analysis of the spectral line shapes with the Kivelson model and computer simulation with EasySpin are discussed. Values of the tumbling correlation times obtained by the two methods are shown to be in good agreement. Comparison of the experimental tumbling correlation times with values calculated with the Stokes‐Einstein model indicates a slip coefficient of 0.066, which is consistent with other reports for nitroxides in various solvents.
Unusually large scalar coupling between geminal protons in a saturated pyrimidine
Authors: Mazzola Eugene P. , Gutierrez Osvaldo , Fraenkel Gideon A. , Chow Albert , Doyle Michael P. , Mandler Michael D. , Dykstra Ryan , Garg Deeya , Ridge Clark D. 
Published: April 2018

AbstractAn unusually large geminal coupling has been observed in a stereochemically rigid system that permits a favorable coupling alignment between the methylene protons and an adjacent carbon‐carbon double bond. Such couplings have been found to depend on both the alignment of a line connecting the geminal hydrogens and the nodal plane of the adjacent double bond, and the orientation of lone‐pair electrons on adjacent heteroatoms. Electron withdrawal from symmetrical bonding orbitals results in more slightly positive geminal coupling constants while that from antisymmetrical bonding orbitals produces more negative coupling constants, which has been found to be very large in certain rigid systems.
Systematic image alteration due to phase accumulation during RF pulse excitation in pure phase encode magnetic resonance imaging
Authors: McDonald Tess , MacMillan Bryce , Newling Ben , Balcom Bruce J. 
Published: April 2018

AbstractThe SPI/SPRITE class of techniques in magnetic resonance imaging are pure phase encode methods that are well established for systems with short transverse signal lifetimes. Applying a broadband radio‐frequency pulse in the presence of a magnetic field gradient is unconventional in MRI but fundamental to these methods. Ordinarily, it is assumed that the excitation is instantaneous and any possible phase evolution during the RF pulse is ignored. High quality, quantitative imaging of a variety of samples over many years suggests that the off‐resonance effects of the RF pulse, with consequent phase accumulation during the pulse, are not significant. However, a reconsideration of the RF pulse behavior in related work has shown that phase accumulation during the pulse may be non‐negligible in some circumstances.The effect of phase accumulation during the RF pulse is investigated through simulation of one‐dimensional SPI experiments and is shown to manifest as a systematic scaling of the image field‐of‐view (FOV). The FOV scaling effect is also verified experimentally. One‐dimensional profiles of a cylindrical elastomer sample were acquired employing a 2.4 T horizontal bore magnet. Experiments were undertaken with variation of the experimental RF pulse duration. Under typical experimental parameters, neglecting the phase accumulation during the RF pulse is acceptable.
Sustainable facility location‐allocation problem under uncertainty
Authors: Wang Cheng , Hu Zhuo , Xie Ming , Bian Yuxiang 
Published: April 2018

SummaryThis paper addresses a sustainable facility location‐allocation problem under uncertain environment with considering economic and sustainable dimensions simultaneously. We establish three types of belief degree constrained mathematical models to investigate the problem under the optimistic value criterion, the pessimistic value criterion, and the Hurwicz criterion. The corresponding crisp determinants of the models are derived, and several properties of the models are also discussed. The theoretical analysis demonstrates that the optimal objective values of the models crucially depend on the predetermined confidence level given by decision makers. What's more, the total cost of the problem in the belief degree constrained Hurwicz criterion model decreases as Hurwicz coefficient becomes larger. To evaluate the performance of our novel models, several numerical examples are conducted. The numerical results are obtained by using the standard optimization software LINGO.
Weak interspecific interactions in a sagebrush steppe? Conflicting evidence from observations and experiments
Authors: Adler Peter B. , Kleinhesselink Andrew , Hooker Giles , Taylor Joshua B. , Teller Brittany , Ellner Stephen P. 
Published: April 2018

AbstractStable coexistence requires intraspecific limitations to be stronger than interspecific limitations. The greater the difference between intra‐ and interspecific limitations, the more stable the coexistence, and the weaker the competitive release any species should experience following removal of competitors. We conducted a removal experiment to test whether a previously estimated model, showing surprisingly weak interspecific competition for four dominant species in a sagebrush steppe, accurately predicts competitive release. Our treatments were (1) removal of all perennial grasses and (2) removal of the dominant shrub, Artemisia tripartita. We regressed survival, growth, and recruitment on the locations, sizes, and species identities of neighboring plants, along with an indicator variable for removal treatment. If our “baseline” regression model, which accounts for local plant–plant interactions, accurately explains the observed responses to removals, then the removal coefficient should be non‐significant. For survival, the removal coefficients were never significantly different from zero, and only A. tripartita showed a (negative) response to removals at the recruitment stage. For growth, the removal treatment effect was significant and positive for two species, Poa secunda and Pseudoroegneria spicata, indicating that the baseline model underestimated interspecific competition. For all three grass species, population models based on the vital rate regressions that included removal effects projected 1.4‐ to 3‐fold increases in equilibrium population size relative to the baseline model (no removal effects). However, we found no evidence of higher response to removal in quadrats with higher pretreatment cover of A. tripartita, or by plants experiencing higher pre‐treatment crowding by A. tripartita, raising questions about the mechanisms driving the positive response to removal. While our results show the value of combining observations with a simple removal experiment, more tightly controlled experiments focused on underlying mechanisms may be required to conclusively validate or reject predictions from phenomenological models.
Drivers of leaf carbon exchange capacity across biomes at the continental scale
Authors: Smith Nicholas G. , Dukes Jeffrey S. 
Published: April 2018

AbstractRealistic representations of plant carbon exchange processes are necessary to reliably simulate biosphere–atmosphere feedbacks. These processes are known to vary over time and space, though the drivers of the underlying rates are still widely debated in the literature. Here, we measured leaf carbon exchange in >500 individuals of 98 species from the Neotropics to high boreal biomes to determine the drivers of photosynthetic and dark respiration capacity. Covariate abiotic (long‐ and short‐term climate) and biotic (plant type, plant size, ontogeny, water status) data were used to explore significant drivers of temperature‐standardized leaf carbon exchange rates. Using model selection, we found the previous week's temperature and soil moisture at the time of measurement to be a better predictor of photosynthetic capacity than long‐term climate, with the combination of high recent temperatures and low soil moisture tending to decrease photosynthetic capacity. Non‐trees (annual and perennials) tended to have greater photosynthetic capacity than trees, and, within trees, adults tended to have greater photosynthetic capacity than juveniles, possibly as a result of differences in light availability. Dark respiration capacity was less responsive to the assessed drivers than photosynthetic capacity, with rates best predicted by multi‐year average site temperature alone. Our results suggest that, across large spatial scales, photosynthetic capacity quickly adjusts to changing environmental conditions, namely light, temperature, and soil moisture. Respiratory capacity is more conservative and most responsive to longer‐term conditions. Our results provide a framework for incorporating these processes into large‐scale models and a data set to benchmark such models.
Habitat availability and ontogenetic shifts alter bottlenecks in size‐structured fish populations
Authors: Cantin Ariane , Post John R. 
Published: April 2018

AbstractFor species that utilize different habitats throughout their life cycle, the habitat limitation at a given stage can act as a bottleneck on population abundance, impacting density‐dependent processes such as individual growth and survival. We explore the influence of habitat limitation on population dynamics by developing a multi‐stage population model based on lake‐dwelling rainbow trout (Oncorhynchus mykiss) populations where adults occupy the lake habitat but use tributaries for spawning and juvenile rearing. The model details density‐dependent ecological processes and ontogenetic habitat shifts, harvest mortality, and the impact of climate on growth. We ran model simulations using a range of early life stage habitat availabilities and climatic conditions representative of the native range of rainbow trout in Canada and compared the results to empirical data. The results suggest that (1) increases in early life stage habitat leads to increases in population abundance but, due to density‐dependent processes, also results in slower growing stunted populations; (2) population bottlenecks can occur at any life stage, even at the adult stage if spawning and rearing habitats are abundant; (3) when the level of competition for early life stages is increased, inter‐cohort competition can lead to population cycles. The model's conclusions are further reinforced by empirical data showing a similar trend in the relationship between fish density and maximum size and providing evidence that limited early life stage habitat leads to lower fish densities and larger fish size. We provide a model that links environmental conditions to population dynamics and is useful for fisheries management and habitat conservation decisions.
Large‐Scale Transdisciplinary Collaboration for Adaptation Research: Challenges and Insights
Authors: Cundill Georgina , Harvey Blane , Tebboth Mark , Cochrane Logan , Currie‐Alder Bruce , Vincent Katharine , Lawn Jon , Nicholls Robert. J. , Scodanibbio Lucia , Prakash Anjal , New Mark , Wester Philippus , Leone Michele , Morchain Daniel , Ludi Eva , DeMaria‐Kinney Jesse , Khan Ahmed , Landry Marie‐Eve 
Published: May 2018

AbstractAn increasing number of research programs seek to support adaptation to climate change through the engagement of large‐scale transdisciplinary networks that span countries and continents. While transdisciplinary research processes have been a topic of reflection, practice, and refinement for some time, these trends now mean that the global change research community needs to reflect and learn how to pursue collaborative research on a large scale. This paper shares insights from a seven‐year climate change adaptation research program that supports collaboration between more than 450 researchers and practitioners across four consortia and 17 countries. The experience confirms the importance of attention to careful design for transdisciplinary collaboration, but also highlights that this alone is not enough. The success of well‐designed transdisciplinary research processes is also strongly influenced by relational and systemic features of collaborative relationships. Relational features include interpersonal trust, mutual respect, and leadership styles, while systemic features include legal partnership agreements, power asymmetries between partners, and institutional values and cultures. In the new arena of large‐scale collaborative science efforts, enablers of transdisciplinary collaboration include dedicated project coordinators, leaders at multiple levels, and the availability of small amounts of flexible funds to enable nimble responses to opportunities and unexpected collaborations.
The magma evolution sequence and geodynamic setting in the Qibaoshan ore area, Wulian County, Shandong Province, China
Authors: Yu Guang‐Yuan , Wang Zhi‐Gao , Wang Ke‐Yong , Li Jian‐Feng , Wang Cheng‐Yang 
Published: May 2018

The Qibaoshan ore area is located in Wulian town, Shandong Province, which is an important polymetallic metallogenic zone containing gold, copper, lead, and zinc. The polymetallic mineralization is mostly related to the Qibaoshan complex. The Qibaoshan complex is composed mainly of pyroxene diorite, andesitic porphyrite, pyroxene andesite porphyrite, amphibole andesite porphyrite, diorite porphyrite, and granodiorite porphyry, among which granodiorite–porphyry is the main wall rock of gold and copper ore body, whereas lead and zinc mineralization is closely related to diorite porphyrite. A combined study of laser ablation–inductively coupled plasma–mass spectrometry zircon U–Pb dating and geochemical analyses (major and trace elements) for 5 Mesozoic plutons from the Qibaoshan complex was carried out to determine their ages, petrogenesis, and tectonic setting. The U–Pb zircon ages measured by laser ablation–inductively coupled plasma–mass spectrometry indicate that the Qibaoshan complex was emplaced in 3 stages, represented by the ~175 Ma pyroxene diorite, ~129 Ma andesitic porphyrite/ porphyrite, ~125 Ma granodiorite‐porphyry, and ~112 Ma diorite porphyrite. Systematic diagenetic chronology and rock geochemistry show that formation of ~175 Ma pyroxene diorite in Qibaoshan ore‐concentrated area is possibly related to the transformation environment from compression to extension of the Sulu orogenic belt and/or of the subduction of the Pacific Plate, whereas the formation of the Early Cretaceous subvolcanic rock has a volcanic arc affinity related to subduction of the Pacific Plate. Based on the previous studies, this paper argues that the metallogenic age of Qibaoshan polymetallic ore‐concentrated area is 125–105 Ma, which is formed in the volcanic arc dynamics environment of the Pacific Plate subduction in the Late Yanshanian. In addition, a small amount of 610–799 Ma and 1.8 Ga was developed in the samples of the pyroxene diorite and andesitic porphyrite, suggesting their source may have great affinities with South China.
The impact of institutions on the competitive advantage of publicly listed family firms in emerging markets
Authors: Duran Patricio , van Essen Marc , Heugens Pursey P. M. A. R. , Kostova Tatiana , Peng Mike W. 
Published: May 2018

Research Summary: We develop an institutional explanation for the finding that the competitive advantage publicly listed family firms (PFFs) enjoy over other publicly listed firms varies across emerging markets. We propose that PFF performance is contingent on the state of four types of institutions—formal constraining, informal constraining, formal enabling, and informal enabling institutions. We test these ideas with a meta‐analysis of 177 primary studies, situated in 49 countries. Our results show that the competitive advantage PFFs enjoy is stronger when formal constraining institutions are less developed and when suitable informal enabling institutions are present. However, their competitive advantage is weaker when formal enabling and informal constraining institutions are less developed. We conclude that the competitive advantage of PFFs in emerging markets is contingent on local institutional conditions.
Managerial Summary: We develop a framework to improve our understanding of how institutions impact the competitive advantage of publicly listed family firms (PFFs) in 49 emerging markets. The framework informs the decisions of PFF owners and managers concerning where to compete and when to invest in distinctive characteristics of family involvement, like a long‐term orientation, familial control, stewardship, and reputational capital. While our baseline expectation is that PFFs enjoy a competitive advantage in emerging markets, the model also specifies in which contexts the competitiveness of PFFs will be compromised. Our framework offers guidance to policymakers interested in increasing the economic contribution PFFs make to their jurisdictions, which they can ensure by developing PFF‐favoring institutions that strengthen the competitive advantage of these firms.
Estimation of vocational aptitudes using functional brain networks
Authors: Sung Yul‐Wan , Kawachi Yousuke , Choi Uk‐Su , Kang Daehun , Abe Chihiro , Otomo Yuki , Ogawa Seiji 
Published: May 2018

AbstractThe success of human life in modern society is highly dependent on occupation. Therefore, it is very important for people to identify and develop a career plan that best suits their aptitude. Traditional test batteries for vocational aptitudes are not oriented to measure developmental changes in job suitability because repeated measurements can introduce bias as the content of the test batteries is learned. In this study, we attempted to objectively assess vocational aptitudes by measuring functional brain networks and identified functional brain networks that intrinsically represented vocational aptitudes for 19 job divisions in a General Aptitude Test Battery. In addition, we derived classifiers based on these networks to predict the aptitudes of our test participants for each job division. Our results suggest that the measurement of brain function can indeed yield an objective evaluation of vocational aptitudes; this technique will enable a person to follow changes in one's job suitability with additional training or learning, paving a new way to advise people on career development.
Learning from failure in healthcare: Dynamic panel evidence of a physician shock effect
Authors: Van Gestel Raf , Müller Tobias , Bosmans Johan 
Published: May 2018

AbstractProcedural failures of physicians or teams in interventional healthcare may positively or negatively predict subsequent patient outcomes. We identify this effect by applying (non)linear dynamic panel methods to data from the Belgian transcatheter aorta valve implantation registry containing information on the first 860 transcatheter aorta valve implantation procedures in Belgium. We find that a previous death of a patient positively and significantly predicts subsequent survival of the succeeding patient. We find that these learning from failure effects are not long‐lived and that learning from failure is transmitted across adverse events.
Design of A Metabolically Stable Tritium‐Tracer of the PI3Kδ‐Inhibitor CDZ173 (Leniolisib) as a Tool to Study Liver Metabolites
Authors: Bauer Carsten , Luu Tong , Eggimann Fabian , Bross Patrick , Gertsch Werner , Hu Cheng , Ramstein Philippe , Bourgailh Julien , Glänzel Albrecht , Dix Ina , Guenat Christian , Soldermann Nicolas , Litherland Karine , Desrayaud Sandrine , Hengy Jean‐Claude , Pearson David , Blanz Joachim , Burkhart Christoph 
Published: April 2018

In this disclosure, we summarize the preliminary metabolic profiling of the PI3Kδ inhibitor CDZ173 (leniolisib, 1a) obtained from incubations of the unlabeled compound and the synthesis of its metabolically stable tritium isotopologue 1b used for metabolite structure confirmation. Access to 1b was achieved when a halogenated precursor was subject to Hal/3H‐exchange. Hence, [3H]CDZ173 with specific activity 630 GBq/mmol, HPLC‐RA 97% and ee = 99.2% was obtained. Synthetic key to the precursor was using a bis‐halo‐pyridine in a Pd‐catalyzed mono‐amination of the tetrahydropyrido‐pyrimidine core. Stereochemistry of the synthetic precursors were confirmed by X‐ray analysis of the unlabeled bis‐halo‐pyridines and chiral HPLC of the tritiated material. The correct position of tritium label in the target, was confirmed by 3H‐NMR difference spectroscopy. Besides, we report on the validation of the radiotracer as a tool for pre‐clinical ADME in incubations with hepatocytes. Based on this data, we present a quantitative metabolite profile of leniolisib which was confirmed by independently synthesized metabolite references. The conformation of CDZ173 was investigated by NMR suggesting two different amide backbones each with specific pyrrolidine puckerings.