Статті в журналах з теми "Strength and directionality of influence"
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1
Maina, E., D. N. Crowther, J. R. Banerjee, and B. Mintz. "Influence of directionality on strength and impact behaviour of high strength steels." Materials Science and Technology 28, no. 4 (April 2012): 390–96. http://dx.doi.org/10.1179/1743284711y.0000000061.
Повний текст джерела
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Jamadar, Akshoy, Chandan Kumar Karan, Subhendu Biswas, and Anindita Das. "Structural influence on stimuli-responsive halogen-bonded luminescent supramolecular polymers from heteroditopic isomers." CrystEngComm 23, no. 8 (2021): 1695–99. http://dx.doi.org/10.1039/d1ce00101a.
Повний текст джерелаАнотація:
Halogen-bonded (XB) supramolecular polymers from two heteroditopic, emissive hydroxyquinoline-based structural isomers displayed distinctly different crystal packing & stimuli-responsive morphologies, due to the varying XB directionality & strength.
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McBeath, Michael K., and Kazunori Morikawa. "Forward-Facing Motion Biases for Rigid and Nonrigid Biologically Likely Transformations." Perceptual and Motor Skills 85, no. 3_suppl (December 1997): 1187–93. http://dx.doi.org/10.2466/pms.1997.85.3f.1187.
Повний текст джерелаАнотація:
When observers are presented directionally ambiguous motion, they exhibit a bias for experiencing movement in the direction in which shapes appear to face. We examined the influence of rigidity of a shape on the forward-facing bias with stimuli whose directionality is biologically specified. In general, the lack of shape correspondence during a nonrigid transformation should weaken the motion percept and decrease forward-facing bias. In contrast, representational momentum cues associated with a biologically likely nonrigid transformation should enhance the motion percept and increase forward-facing bias. Analysis for both rigid and nonrigid conditions indicated statistically significant forward-facing biases, but strength of bias did not differ significantly. The lack of difference between the two conditions suggests that the transformation was not one which allowed the influence of either consistency of correspondence or representational momentum to dominate and confirms that a comparably sized forward-facing bias can occur with both rigidly and nonrigidly transformed shapes.
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Kim, Minkyoung, and Soohwan Kim. "Dynamics of macroscopic diffusion across meta-populations with top-down and bottom-up approaches: A review." Mathematical Biosciences and Engineering 19, no. 5 (2022): 4610–26. http://dx.doi.org/10.3934/mbe.2022213.
Повний текст джерелаАнотація:
<abstract><p>Human interaction patterns on the Web over online social networks vary with the context of communication items (<italic>e.g.,</italic> politics, economics, disasters, celebrities, and etc.), which leads to form unlimited time-evolving curves of information adoption as diffusion proceeds. Online communications often continue to navigate through heterogeneous social systems consisting of a wide range of online media such as social networking sites, blogs, and mainstream news. This makes it very challenging to uncover the underlying causal mechanisms of such macroscopic diffusion. In this respect, we review both top-down and bottom-up approaches to understand the underlying dynamics of an individual item's popularity growth across multiple meta-populations in a complementary way. For a case study, we use a dataset consisting of time-series adopters for over 60 news topics through different online communication channels on the Web. In order to find disparate patterns of macroscopic information propagation, we first generate and cluster the diffusion curves for each target meta-population and then estimate them with two different and complementary approaches in terms of the strength and directionality of influences across the meta-populations. In terms of the strength of influence, we find that synchronous global diffusion is not possible without very strong intra-influence on each population. In terms of the directionality of influence between populations, such concurrent propagation is likely brought by transitive relations among heterogeneous populations. When it comes to social context, controversial news topics in politics and human culture (<italic>e.g.,</italic> political protests, multiculturalism failure) tend to trigger more synchronous than asynchronous diffusion patterns across different social media on the Web. We expect that this study can help to understand dynamics of macroscopic diffusion across complex systems in diverse application domains.</p></abstract>
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Yannacone, Seth, Marek Freindorf, Yunwen Tao, Wenli Zou та Elfi Kraka. "Local Vibrational Mode Analysis of π–Hole Interactions between Aryl Donors and Small Molecule Acceptors". Crystals 10, № 7 (30 червня 2020): 556. http://dx.doi.org/10.3390/cryst10070556.
Повний текст джерелаАнотація:
11 aryl–lone pair and three aryl–anion π –hole interactions are investigated, along with the argon–benzene dimer and water dimer as reference compounds, utilizing the local vibrational mode theory, originally introduced by Konkoli and Cremer, to quantify the strength of the π –hole interaction in terms of a new local vibrational mode stretching force constant between the two engaged monomers, which can be conveniently used to compare different π –hole systems. Several factors have emerged which influence strength of the π –hole interactions, including aryl substituent effects, the chemical nature of atoms composing the aryl rings/ π –hole acceptors, and secondary bonding interactions between donors/acceptors. Substituent effects indirectly affect the π –hole interaction strength, where electronegative aryl-substituents moderately increase π –hole interaction strength. N-aryl members significantly increase π –hole interaction strength, and anion acceptors bind more strongly with the π –hole compared to charge neutral acceptors (lone–pair donors). Secondary bonding interactions between the acceptor and the atoms in the aryl ring can increase π –hole interaction strength, while hydrogen bonding between the π –hole acceptor/donor can significantly increase or decrease strength of the π –hole interaction depending on the directionality of hydrogen bond donation. Work is in progress expanding this research on aryl π –hole interactions to a large number of systems, including halides, CO, and OCH3− as acceptors, in order to derive a general design protocol for new members of this interesting class of compounds.
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Sherrill, Samantha P., Nicholas M. Timme, John M. Beggs, and Ehren L. Newman. "Partial information decomposition reveals that synergistic neural integration is greater downstream of recurrent information flow in organotypic cortical cultures." PLOS Computational Biology 17, no. 7 (July 12, 2021): e1009196. http://dx.doi.org/10.1371/journal.pcbi.1009196.
Повний текст джерелаАнотація:
The directionality of network information flow dictates how networks process information. A central component of information processing in both biological and artificial neural networks is their ability to perform synergistic integration–a type of computation. We established previously that synergistic integration varies directly with the strength of feedforward information flow. However, the relationships between both recurrent and feedback information flow and synergistic integration remain unknown. To address this, we analyzed the spiking activity of hundreds of neurons in organotypic cultures of mouse cortex. We asked how empirically observed synergistic integration–determined from partial information decomposition–varied with local functional network structure that was categorized into motifs with varying recurrent and feedback information flow. We found that synergistic integration was elevated in motifs with greater recurrent information flow beyond that expected from the local feedforward information flow. Feedback information flow was interrelated with feedforward information flow and was associated with decreased synergistic integration. Our results indicate that synergistic integration is distinctly influenced by the directionality of local information flow.
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Crook, John M., Zoltan F. Kisvárday, and Ulf T. Eysel. "GABA-induced inactivation of functionally characterized sites in cat striate cortex: Effects on orientation tuning and direction selectivity." Visual Neuroscience 14, no. 1 (January 1997): 141–58. http://dx.doi.org/10.1017/s095252380000883x.
Повний текст джерелаАнотація:
AbstractMicroiontophoresis of γ-aminobutyric acid (GABA) was used to reversibly inactivate small sites of defined orientation/direction specificity in layers II-IV of cat area 17 while single cells were recorded in the same area at a horizontal distance of ~350–700 jam. We compared the effect of inactivating iso-orientation sites (where orientation preference was within 22.5 deg) and cross-orientation sites (where it differed by 45–90 deg) on orientation tuning and directionality. The influence of iso-orientation inactivation was tested in 33 cells, seven of which were subjected to alternate inactivation of two iso-orientation sites with opposite direction preference. Of the resulting 40 inactivations, only two (5%) caused significant changes in orientation tuning, whereas 26 (65%) elicited effects on directionality: namely, an increase or a decrease in response to a cell's preferred direction when its direction preference was the same as that at an inactivation site, and an increase in response to a cell's nonpreferred direction when its direction preference was opposite that at an inactivation site. It is argued that the decreases in response to the preferred direction reflected a reduction in the strength of intracortical iso-orientation excitatory connections, while the increases in response were due to the loss of iso-orientation inhibition. Of 35 cells subjected to cross-orientation inactivation, only six (17%) showed an effect on directionality, whereas 21 (60%) showed significant broadening of orientation tuning, with an increase in mean tuning width at half-height of 126%. The effects on orientation tuning were due to increases in response to nonoptimal orientations. Changes in directionality also resulted from increased responses (to preferred or nonpreferred directions) and were always accompanied by broadening of tuning. Thus, the effects of cross-orientation inactivation were presumably due to the loss of a cross-orientation inhibitory input that contributes mainly to orientation tuning by suppressing responses to nonoptimal orientations. Differential effects of iso-orientation and cross-orientation inactivation could be elicited in the same cell or in different cells from the same inactivation site. The results suggest the involvement of three different intracortical processes in the generation of orientation tuning and direction selectivity in area 17: (1) suppression of responses to nonoptimal orientations and directions as a result of cross-orientation inhibition and iso-orientation inhibition between cells with opposite direction preferences; (2) amplification of responses to optimal stimuli via iso-orientation excitatory connections; and (3) regulation of cortical amplification via iso-orientation inhibition.
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Yuan, Siqi, Ruixuan Ma, Conghai Wu, and Shuhai Zhang. "Numerical Simulation of Acoustic Scattering by a Rotating Cylinder Based on the Enhanced Optimized Scheme." Journal of Physics: Conference Series 2329, no. 1 (August 1, 2022): 012001. http://dx.doi.org/10.1088/1742-6596/2329/1/012001.
Повний текст джерелаАнотація:
Abstract In this paper, we develop a new physical model which involves a Taylor vortex around a rotating cylinder. The scattering of sound waves from this new model is investigated by solving the linearized Euler equations under the polar coordinate system in the time domain. We use the enhanced optimized scheme for numerical simulations. Numerical results show that scattering causes a change in the spatial distribution of sound energy as the sound wave passes through a rotating cylinder. The directionality of the scattered field varies significantly with the length ratio of the acoustic wavelength to the radius of the rotating cylinder and the vortex intensity. The influences of the ratio and the strength on the directivities and intensities of scattered fields are analyzed. It is shown that the intensity of the scattering cross-section increases with the strength of the vortex. The pressure of the scattered sound fields has a phase shift induced by the couple scattering from the cylinder and the vortex.
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Aitken, A. R. A., E.-J. Holden, and M. C. Dentith. "Semiautomated quantification of the influence of data richness on confidence in the geologic interpretation of aeromagnetic maps." GEOPHYSICS 78, no. 2 (March 1, 2013): J1—J13. http://dx.doi.org/10.1190/geo2012-0033.1.
Повний текст джерелаАнотація:
Geologic interpretations of aeromagnetic maps are highly subjective but are rarely accompanied by a quantitative confidence assessment, which is a key limitation on the usefulness of the results. Here, we outline a method with which the relative level of data richness can be assessed quantitatively, leading to an improved understanding of spatial variations in interpretational confidence. Simple rules were used to quantify the likely influence of several major sources of uncertainty. These were: (1) the level of geologic constraint, using the local abundance of outcropping rock and the quality of geologic mapping; (2) the interpretability of the aeromagnetic data, considering the strength of edge-like features and the degree of directionality of these features, a proxy for structural complexity; (3) data collection and processing errors, including gridding errors, derived from the statistical error returned during kriging, and the influence of anisotropic line data collection on the detection of gradients. From these individual sources of uncertainty, an overall data richness map was generated through a weighted summation of these grids. Weightings were assigned so as to best match the result to the interpreter’s perception of interpretational confidence. This method produced a map of data richness, which reflects the opportunity that the data provided to the interpreter to make a correct interpretation. An example from central Australia indicated that the data influences were preserved over a moderate range of weighting factors, and that strong bias was required to override these. In addition to providing a confidence assessment, this method also provides a way to test the potential benefits of additional data collection.
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Moncayo-Donoso, Miguelangel, Gustavo A. Rico-Llanos, Diego A. Garzón-Alvarado, José Becerra, Rick Visser, and Marta R. Fontanilla. "The Effect of Pore Directionality of Collagen Scaffolds on Cell Differentiation and In Vivo Osteogenesis." Polymers 13, no. 18 (September 20, 2021): 3187. http://dx.doi.org/10.3390/polym13183187.
Повний текст джерелаАнотація:
Although many bone substitutes have been designed and produced, the development of bone tissue engineering products that mimic the microstructural characteristics of native bone remains challenging. It has been shown that pore orientation within collagen scaffolds influences bone matrix formation by the endochondral route. In addition, that the unidirectional orientation of the scaffolds can limit the growth of blood vessels. However, a comparison between the amount of bone that can be formed in scaffolds with different pore orientations in addition to analyzing the effect of loading osteogenic and proangiogenic factors is still required. In this work we fabricated uni- and multidirectional collagen sponges and evaluated their microstructural, physicochemical, mechanical and biological characteristics. Although the porosity and average pore size of the uni- and multidirectional scaffolds was similar (94.5% vs. 97.1% and 260 µm vs. 269 µm, respectively) the unidirectional sponges had a higher tensile strength, Young’s modulus and capacity to uptake liquids than the multidirectional ones (0.271 MPa vs. 0.478 MPa, 9.623 MPa vs. 3.426 MPa and 8000% mass gain vs. 4000%, respectively). Culturing of rat bone marrow mesenchymal stem cells demonstrated that these scaffolds support cell growth and osteoblastic differentiation in the presence of BMP-2 in vitro, although the pore orientation somehow affected cell attachment and differentiation. The evaluation of the ability of the scaffolds to support bone growth when loaded with BMP-2 or BMP-2 + VEGF in an ectopic rat model showed that they both supported bone formation. Histological analysis and quantification of mineralized matrix revealed that the pore orientation of the collagen scaffolds influenced the osteogenic process.
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Mrowka, Ralf, Laura Cimponeriu, Andreas Patzak, and Michael G. Rosenblum. "Directionality of coupling of physiological subsystems: age-related changes of cardiorespiratory interaction during different sleep stages in babies." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 285, no. 6 (December 2003): R1395—R1401. http://dx.doi.org/10.1152/ajpregu.00373.2003.
Повний текст джерелаАнотація:
Activity of many physiological subsystems has a well-expressed rhythmic character. Often, a dependency between physiological rhythms is established due to interaction between the corresponding subsystems. Traditional methods of data analysis allow one to quantify the strength of interaction but not the causal interrelation that is indispensable for understanding the mechanisms of interaction. Here we present a recently developed method for quantification of coupling direction and apply it to an important problem. Namely, we study the mutual influence of respiratory and cardiovascular rhythms in healthy newborns within the first 6 mo of life in quiet and active sleep. We find an age-related change of the coupling direction: the interaction is nearly symmetric during the first days and becomes practically unidirectional (from respiration to heart rhythm) at the age of 6 mo. Next, we show that the direction of interaction is mainly determined by respiratory frequency. If the latter is less than ≈0.6 Hz, the interaction occurs dominantly from respiration to heart. With higher respiratory frequencies that only occur at very young ages, the dominating direction is less pronounced or even abolished. The observed dependencies are not related to sleep stage, suggesting that the coupling direction is determined by system-inherent dynamical processes, rather than by functional modulations. The directional analysis may be applied to other interacting narrow band oscillatory systems, e.g., in the central nervous system. Thus it is an important step forward in revealing and understanding causal mechanisms of interactions.
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Arnold, Vicky, Tanya S. Benford, Clark Hampton, and Steve G. Sutton. "Enterprise Risk Management: Re-Conceptualizing the Role of Risk and Trust on Information Sharing in Transnational Alliances." Journal of Information Systems 28, no. 2 (May 1, 2014): 257–85. http://dx.doi.org/10.2308/isys-50812.
Повний текст джерелаАнотація:
ABSTRACT Globalization places greater emphasis on the development of transnational alliances. The greatest benefits from alliances are derived from high-level information sharing, but vulnerability escalates with information sharing. This study examines risk in transnational alliances based on a theoretical model drawing from enterprise risk management (ERM) as a strategic management effort. This theoretical model posits that ERM strategies focus on business risk as the primary determinant of alliance partner selection and continuity, particularly within global relationships, whereas prior management control research focused on trust. The purpose of this study is to examine the influence of ERM on risk and trust associated with transnational alliances and the resulting impact on interorganizational information sharing. Survey data are gathered from 200 senior-level managers monitoring transnational alliances. Structural equation modeling is used to test the hypothesized relationships. Results provide strong support for the research model, showing that high ERM is associated with decreased risk, increased trust, and enhanced information sharing. Given the ongoing debate over the relationship directionality between trust and risk, we conducted additional sensitivity testing. Competing models focusing on trust as the key control mechanism are tested to assess the strength of our research model. Our risk-oriented research model demonstrates stronger explanatory power than competing models. Overall, our results show ERM substantially alters strategic management of transnational alliances, and has become a major influence on interorganizational risk, trust, and information sharing.
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Wilden, J., H. Frank, C. Theiler, T. Seefeld, and G. Sepold. "Simulation of laser cladding." Journal de Physique IV 120 (December 2004): 397–403. http://dx.doi.org/10.1051/jp4:2004120045.
Повний текст джерелаАнотація:
Nickel and titanium aluminides already show a high potential for use in lightweight applications at elevated temperatures; however, the strength of these intermetallics can be increased by directional solidification. These materials show a brittle behaviour at temperatures less than 600°C. Strength and ductility of aluminides are controlled by phase formation during solidification. The problem of crack formation had to be solved for laser rapid prototyping of intermetallics, and the process conditions for formation of directionally solidified structures have to be specified in order to generate directionally solidified TiAl parts properly. A model was developed to determine the influence of the process parameters on melt pool geometry, solidification time, and the formed structure. Temperature gradients and cooling rates were calculated using a simulation that also included feedstock material injection rate and process parameters. The experimental results were analysed using these simulations, and the process parameters were optimised so that crack-free laser-generated TiAl parts exhibiting a partially directionally solidified structure could be produced. The comparison of the simulated and experimental results led to process guidelines for laser generation of directionally solidified TiAl components.
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Hayashi, Eri, Kei Hashimoto, Morgan L. Thomas, Seiji Tsuzuki, and Masayoshi Watanabe. "Role of Cation Structure in CO2 Separation by Ionic Liquid/Sulfonated Polyimide Composite Membrane." Membranes 9, no. 7 (July 4, 2019): 81. http://dx.doi.org/10.3390/membranes9070081.
Повний текст джерелаАнотація:
The development of suitable separation technologies for the separation of carbon dioxide is a pressing technological requirement. The application of ion gel membranes for this purpose continues to stimulate a great deal of research, and in this study we focus on the chemical structure of the ionic liquid component in the ion gel, and its interactions with the sulfonated polyimide polymer. Whilst such membranes are known to give promising carbon dioxide separation properties together with mechanical strength and thin-film-processability, we further elaborate on how changing the cation of the ionic liquid from a typical imidazolium cation to a protic variant effects the physicochemical, thermal, and structural properties of the membranes, and how these changes further influence the carbon dioxide separation properties. We compare and contrast our findings with our earlier study on protic and aprotic ammonium-based ionic liquids, and highlight that for CO2 absorption behavior in the imidazolium systems, the importance of directionality of interactions (ion pairs exhibit a large energy stabilization only for a specific geometrical arrangement of cation and anion, e.g., hydrogen bonding rather than Coulombic interaction) between cation and anion applies not only to the protic system, but also to the nominally aprotic cation. Finally, we demonstrate that the phase separation behavior in the ion gels is an important factor in determining the carbon dioxide separation behavior.
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Bange, Manuel, Gabriel Gonzalez-Escamilla, Tabea Marquardt, Angela Radetz, Christian Dresel, Damian Herz, Wolfgang Immanuel Schöllhorn, Sergiu Groppa, and Muthuraman Muthuraman. "Deficient Interhemispheric Connectivity Underlies Movement Irregularities in Parkinson’s Disease." Journal of Parkinson's Disease 12, no. 1 (January 21, 2022): 381–95. http://dx.doi.org/10.3233/jpd-212840.
Повний текст джерелаАнотація:
Background: Movement execution is impaired in patients with Parkinson’s disease. Evolving neurodegeneration leads to altered connectivity between distinct regions of the brain and altered activity at interconnected areas. How connectivity alterations influence complex movements like drawing spirals in Parkinson’s disease patients remains largely unexplored. Objective: We investigated whether deteriorations in interregional connectivity relate to impaired execution of drawing. Methods: Twenty-nine patients and 31 age-matched healthy control participants drew spirals with both hands on a digital graphics tablet, and the regularity of drawing execution was evaluated by sample entropy. We recorded resting-state fMRI and task-related EEG, and calculated the time-resolved partial directed coherence to estimate effective connectivity for both imaging modalities to determine the extent and directionality of interregional interactions. Results: Movement performance in Parkinson’s disease patients was characterized by increased sample entropy, corresponding to enhanced irregularities in task execution. Effective connectivity between the motor cortices of both hemispheres, derived from resting-state fMRI, was significantly reduced in Parkinson’s disease patients in comparison to controls. The connectivity strength in the nondominant to dominant hemisphere direction in both modalities was inversely correlated with irregularities during drawing, but not with the clinical state. Conclusion: Our findings suggest that interhemispheric connections are affected both at rest and during drawing movements by Parkinson’s disease. This provides novel evidence that disruptions of interhemispheric information exchange play a pivotal role for impairments of complex movement execution in Parkinson’s disease patients.
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Martín-Serra, Alberto, Olga Nanova, Ceferino Varón-González, Germán Ortega, and Borja Figueirido. "Phenotypic integration and modularity drives skull shape divergence in the Arctic fox ( Vulpes lagopus ) from the Commander Islands." Biology Letters 15, no. 9 (September 25, 2019): 20190406. http://dx.doi.org/10.1098/rsbl.2019.0406.
Повний текст джерелаАнотація:
Phenotypic integration and modularity influence morphological disparity and evolvability. However, studies addressing how morphological integration and modularity change for long periods of genetic isolation are scarce. Here, we investigate patterns of phenotypic integration and modularity in the skull of phenotypically and genetically distinct populations of the Artic fox ( Vulpes lagopus ) from the Commander Islands of the Aleutian belt (i.e. Bering and Mednyi) that were isolated ca 10 000 years by ice-free waters of the Bering sea. We use three-dimensional geometric morphometrics to quantify the strength of modularity and integration from inter-individual variation (static) and from fluctuating asymmetry (random developmental variation) in both island populations compared to the mainland population (i.e. Chukotka) and we investigated how changes in morphological integration and modularity affect disparity and the directionality of trait divergence. Our results indicate a decrease in morphological integration concomitant to an increase in disparity at a developmental level, from mainland to the smallest and farthest population of Mednyi. However, phenotypic integration is higher in both island populations accompanied by a reduction in disparity compared to the population of mainland at a static level. This higher integration may have favoured morphological adaptive changes towards specific feeding behaviours related to the extreme environmental settings of islands. Our study demonstrates how shifts in phenotypic integration and modularity can facilitate phenotypic evolvability at the intraspecific level that may lead to lineage divergence at macroevolutioanry scales.
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Lemos-Costa, Paula, Ayana B. Martins, John N. Thompson, and Marcus A. M. de Aguiar. "Gene flow and metacommunity arrangement affects coevolutionary dynamics at the mutualism–antagonism interface." Journal of The Royal Society Interface 14, no. 130 (May 2017): 20160989. http://dx.doi.org/10.1098/rsif.2016.0989.
Повний текст джерелаАнотація:
Interspecific interactions are affected by community context and, as a consequence, show spatial variation in magnitude and sign. The selective forces imposed by interactions at the mutualism–antagonism interface are a consequence of the traits involved and their matching between species. If mutualistic and antagonistic communities are linked by gene flow, coevolution between a pair of interacting species is influenced by how selection varies in space. Here we investigate the effects of metacommunity arrangement, i.e. patterns of connection between communities and the number of communities, on the coevolutionary dynamics between two species for which the sign and magnitude of the interaction varies across the landscape. We quantify coevolutionary outcome as an index that can be decomposed into the contribution of intraspecific genetic diversity and interspecific interaction. We show that polymorphisms and mismatches are an expected outcome, which is influenced by spatial structure, interaction strength and the degree of gene flow. The index describes how variation is distributed within and between species, and provides information on the directionality of the mismatches and polymorphisms. Finally, we argue that depending on metacommunity arrangement, some communities have disproportionate roles in maintaining genetic diversity, with implications for the coevolution of interacting species in a fragmented landscape.
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Brovelli, Andrea. "Statistical Analysis of Single-Trial Granger Causality Spectra." Computational and Mathematical Methods in Medicine 2012 (2012): 1–10. http://dx.doi.org/10.1155/2012/697610.
Повний текст джерелаАнотація:
Granger causality analysis is becoming central for the analysis of interactions between neural populations and oscillatory networks. However, it is currently unclear whether single-trial estimates of Granger causality spectra can be used reliably to assess directional influence. We addressed this issue by combining single-trial Granger causality spectra with statistical inference based on general linear models. The approach was assessed on synthetic and neurophysiological data. Synthetic bivariate data was generated using two autoregressive processes with unidirectional coupling. We simulated two hypothetical experimental conditions: the first mimicked a constant and unidirectional coupling, whereas the second modelled a linear increase in coupling across trials. The statistical analysis of single-trial Granger causality spectra, based ont-tests and linear regression, successfully recovered the underlying pattern of directional influence. In addition, we characterised the minimum number of trials and coupling strengths required for significant detection of directionality. Finally, we demonstrated the relevance for neurophysiology by analysing two local field potentials (LFPs) simultaneously recorded from the prefrontal and premotor cortices of a macaque monkey performing a conditional visuomotor task. Our results suggest that the combination of single-trial Granger causality spectra and statistical inference provides a valuable tool for the analysis of large-scale cortical networks and brain connectivity.
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Panicker, Sumith R., Tadayuki Yago, Bojing Shao, and Rodger P. McEver. "Neutrophils lacking ERM proteins polarize and crawl directionally but have decreased adhesion strength." Blood Advances 4, no. 15 (August 6, 2020): 3559–71. http://dx.doi.org/10.1182/bloodadvances.2020002423.
Повний текст джерелаАнотація:
Abstract Ezrin/radixin/moesin (ERM) proteins are adaptors that link the actin cytoskeleton to the cytoplasmic domains of membrane proteins. Leukocytes express mostly moesin with lower levels of ezrin but no radixin. When leukocytes are activated, ERMs are postulated to redistribute membrane proteins from microvilli into uropods during polarization and to transduce signals that influence adhesion and other responses. However, these functions have not been tested in leukocytes lacking all ERMs. We used knockout (KO) mice with neutrophils lacking ezrin, moesin, or both proteins (double knockout [DKO]) to probe how ERMs modulate cell shape, adhesion, and signaling in vitro and in vivo. Surprisingly, chemokine-stimulated DKO neutrophils still polarized and redistributed ERM-binding proteins such as PSGL-1 and CD44 to the uropods. Selectin binding to PSGL-1 on moesin KO or DKO neutrophils activated kinases that enable integrin-dependent slow rolling but not those that generate neutrophil extracellular traps. Flowing neutrophils of all genotypes rolled normally on selectins and, upon chemokine stimulation, arrested on integrin ligands. However, moesin KO and DKO neutrophils exhibited defective integrin outside-in signaling and reduced adhesion strength. In vivo, DKO neutrophils displayed normal directional crawling toward a chemotactic gradient, but premature detachment markedly reduced migration from venules into inflamed tissues. Our results demonstrate that stimulated neutrophils do not require ERMs to polarize or to move membrane proteins into uropods. They also reveal an unexpected contribution of moesin to integrin outside-in signaling and adhesion strengthening.
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Beguerisse-Díaz, Mariano, Guillermo Garduño-Hernández, Borislav Vangelov, Sophia N. Yaliraki, and Mauricio Barahona. "Interest communities and flow roles in directed networks: the Twitter network of the UK riots." Journal of The Royal Society Interface 11, no. 101 (December 6, 2014): 20140940. http://dx.doi.org/10.1098/rsif.2014.0940.
Повний текст джерелаАнотація:
Directionality is a crucial ingredient in many complex networks in which information, energy or influence are transmitted. In such directed networks, analysing flows (and not only the strength of connections) is crucial to reveal important features of the network that might go undetected if the orientation of connections is ignored. We showcase here a flow-based approach for community detection through the study of the network of the most influential Twitter users during the 2011 riots in England. Firstly, we use directed Markov Stability to extract descriptions of the network at different levels of coarseness in terms of interest communities, i.e. groups of nodes within which flows of information are contained and reinforced. Such interest communities reveal user groupings according to location, profession, employer and topic. The study of flows also allows us to generate an interest distance, which affords a personalized view of the attention in the network as viewed from the vantage point of any given user. Secondly, we analyse the profiles of incoming and outgoing long-range flows with a combined approach of role-based similarity and the novel relaxed minimum spanning tree algorithm to reveal that the users in the network can be classified into five roles. These flow roles go beyond the standard leader/follower dichotomy and differ from classifications based on regular/structural equivalence. We then show that the interest communities fall into distinct informational organigrams characterized by a different mix of user roles reflecting the quality of dialogue within them. Our generic framework can be used to provide insight into how flows are generated, distributed, preserved and consumed in directed networks.
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Asthana, R., R. Tiwari, and S. N. Tewari. "Influence of Cr and W alloying on the fiber-matrix interfacial shear strength in cast and directionally solidified sapphire nial composites." Metallurgical and Materials Transactions A 26, no. 8 (August 1995): 2175–84. http://dx.doi.org/10.1007/bf02670688.
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Bayram, Ümit, and Necmettin Maraşlı. "Influence of Growth Rate on Eutectic Spacing, Microhardness, and Ultimate Tensile Strength in the Directionally Solidified Al-Cu-Ni Eutectic Alloy." Metallurgical and Materials Transactions B 49, no. 6 (September 17, 2018): 3293–305. http://dx.doi.org/10.1007/s11663-018-1404-7.
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Livingston, Kara, Micaela Karlsen, Gail Rogers, Sai Das, Alice Lichtenstein, Sara Folta, Remco Chang, Christina Economos, Paul Jacques, and Nicola McKeown. "Differences in Eating Behavior Among Followers of Popular Diets Across Categories of Perceived Adherence." Current Developments in Nutrition 5, Supplement_2 (June 2021): 980. http://dx.doi.org/10.1093/cdn/nzab051_024.
Повний текст джерелаАнотація:
Abstract Objectives To understand how eating behaviors, susceptibility to the food environment, and perceived dietary habit strength differ across self-reported categories of adherence. Methods We used data in a sample (n = 2829) from Adhering to Dietary Approaches for Personal Taste (ADAPT), an online study conducted in self-identified popular diet followers. Adherence was categorized into 3 groups: >95% of the time (high adherers = HA), between 75–95% (moderate adherers = MA); <75% time (lower adherers = LA). The Power of Food Scale (POF) assessed susceptibility to the food environment (availability, presentation, taste), with higher scores indicating food has a higher power over dietary decisions. The Three-Factor Eating Questionnaire captured cognitive restraint (CR), uncontrolled eating (UE), and emotional eating (EE), with higher scores indicating greater response to the specific eating behavior. The Self-Report Habit Index (SRHI) measured perceived habit strength with respect to eating, with a lower score indicating stronger habits. We used ANCOVA adjusting for age, sex, time on diet, and diet group to compare POF, CR, UE, EE, and SRHI outcomes across adherence groups. Results Sixty six percent were HA (n = 1881), 28% MA (n = 787), and 6% LA (n = 161). LA were significantly more susceptible to food availability (mean [95% CI] = 14.9 [13.8–16.1]), presentation (12.1 [11.2–13.1]), and taste (13.4 [12.6–14.2], compared to HA (11 [10.7–11.3], 8 [7.8–8.3],11.6 [11.4–11.9]), respectively. LA indicated significantly greater UE (21 [20.2–21.9]) than HA (17 [16.7–17.4]) and EE (LA = 8 [7.5–8.4] vs. HA = 6.1 [6–6.3]). No significant differences were observed with respect to CR. LA reported weaker SRHI habits (3.4 [3.2–3.6]) compared to HA (1.7 [1.7–1.8]). Differences seen between the LA and MA were similar to those described for HA. Conclusions Our findings show that higher self-reported adherence to dietary patterns is associated with lower susceptibility to negative influences in the food environment, lower uncontrolled and emotional eating, and greater habit strength. Future research should investigate the directionality of the relationship between eating behavior and adherence. Funding Sources USDA Cooperative Agreements 58-8050-9-004 & 58-8050-4-003, General Mills Bell Institute of Health & Nutrition
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Mazerolles, Léo, N. Piquet, M. F. Trichet, and Michel Parlier. "Microstructures and Interfaces in Melt-Growth Al2O3-Ln2O3 Based Eutectic Composites." Advances in Science and Technology 45 (October 2006): 1377–84. http://dx.doi.org/10.4028/www.scientific.net/ast.45.1377.
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Directionally solidified oxide eutectic ceramics were prepared from Al2O3, Ln2O3 and ZrO2 based binary or ternary systems. Their microstructures consist of continuous networks of single-crystal Al2O3 and oxide compounds (LnAlO3, Ln3Al5O12) which interpenetrate without grain boundaries. The outstanding stability of these microstructures gives rise to a high strength and creep resistance at high temperature. Influence of growth conditions on the morphology of the as-obtained microstructures was studied. Preferred growth directions, orientation relationships between phases and single-crystal homogeneity of specimen were revealed. Low residual stresses were measured in the binary eutectics and fracture toughness at room temperature was improved by the addition of zirconia at a eutectic composition in ternary systems.
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Lucon-Xiccato, Tyrone, Marco Dadda, and Angelo Bisazza. "Vegetation cover induces developmental plasticity of lateralization in tadpoles." Current Zoology 66, no. 4 (December 5, 2019): 393–99. http://dx.doi.org/10.1093/cz/zoz061.
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Abstract Lateralization of cognitive functions influences a large number of fitness-related behaviors and shows, in most species, substantial variation in strength and direction. Laboratory works and field data have suggested that this variation is often due to adaptive phenotypic plasticity. Strong lateralization should be favored in some ecological conditions, for example, under high risk of predation. For anuran tadpoles, the presence of cover affects predation risk, with tadpoles being more exposed to predators in environments with reduced cover. We tested the hypothesis that the amount of cover experienced early in life affects lateralization in the edible frog, Pelophylax esculentus, tadpoles. We exposed embryos and larvae to high or low vegetation cover environments. For half of the subjects, the treatment was constant whereas the remaining subjects were switched to the opposite treatment after hatching. In agreement with the theoretical expectation, tadpoles exposed to low vegetation cover for the entire development were more lateralized and showed a stronger alignment in directionality of lateralization compared with tadpoles exposed to high vegetation cover. This indicates a possible role of natural variation in vegetation abundance and developmental plasticity as determinants of between-population and between-individual differences in lateralization. We also found that shifting from high to low vegetation cover treatments and vice versa disrupted lateralization alignment, suggesting that developmental trajectories for this trait are determined at the embryonic stage and need environmental stability to be fully expressed.
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Greco, Alberto, Luca Faes, Vincenzo Catrambone, Riccardo Barbieri, Enzo Pasquale Scilingo, and Gaetano Valenza. "Lateralization of directional brain-heart information transfer during visual emotional elicitation." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 317, no. 1 (July 1, 2019): R25—R38. http://dx.doi.org/10.1152/ajpregu.00151.2018.
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Previous studies have characterized the physiological interactions between central nervous system (brain) and peripheral cardiovascular system (heart) during affective elicitation in healthy subjects; however, questions related to the directionality of this functional interplay have been gaining less attention from the scientific community. Here, we explore brain-heart interactions during visual emotional elicitation in healthy subjects using measures of Granger causality (GC), a widely used descriptor of causal influences between two dynamical systems. The proposed approach inferences causality between instantaneous cardiovagal dynamics estimated from inhomogeneous point-process models of the heartbeat and high-density electroencephalogram (EEG) dynamics in 22 healthy subjects who underwent pleasant/unpleasant affective elicitation by watching pictures from the International Affective Picture System database. Particularly, we calculated the GC indexes between the EEG spectrogram in the canonical θ-, α-, β-, and γ-bands and both the instantaneous mean heart rate and its continuous parasympathetic modulations (i.e., the instantaneous HF power). Thus we looked for significant statistical differences among GC values estimated during the resting state, neutral elicitation, and pleasant/unpleasant arousing elicitation. As compared with resting state, coupling strength increases significantly in the left hemisphere during positive stimuli and in the right hemisphere during negative stimuli. Our results further reveal a correlation between emotional valence and lateralization of the dynamical information transfer going from brain-to-heart, mainly localized in the prefrontal, somatosensory, and posterior cortexes, and of the information transfer from heart-to-brain, mainly reflected into the fronto-parietal cortex oscillations in the γ-band (30 −45 Hz).
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Celebrini, S., and W. T. Newsome. "Microstimulation of extrastriate area MST influences performance on a direction discrimination task." Journal of Neurophysiology 73, no. 2 (February 1, 1995): 437–48. http://dx.doi.org/10.1152/jn.1995.73.2.437.
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1. Evidence from single-unit recordings suggests that neurons in the medial superior temporal visual area (MST) carry directional signals that influence psychophysical judgements of motion direction. We tested this hypothesis by electrically stimulating clusters of directionally selective neurons in MST (the dorsomedial subdivision, primarily) while rhesus monkeys performed a two-alternative, forced-choice direction discrimination task. 2. We performed forty-six microstimulation experiments on two rhesus monkeys. The visual stimuli were dynamic random dot patterns in which the strength of a coherent motion signal could be varied continuously about psychophysical threshold. The monkeys were rewarded for reporting correctly the direction of the coherent motion signal. Microstimulation was applied on half the trials, selected randomly, and the psychophysical data were analyzed to determine whether stimulation of MST neurons influenced the monkeys' choices. 3. Microstimulation influenced the monkeys' performance in a statistically significant manner in 67% of the experiments. In all but one of the significant experiments, microstimulation biased the monkeys' choices toward the direction of motion encoded by MST neurons at the stimulation site. Microstimulation had little effect on the slopes of the psychometric functions, suggesting that the stimulation-induced neural activity resembled a relatively pure motion "signal" rather than "noise." 4. Microstimulation exerted strong effects on the monkeys' behavior only when the visual stimulus was located within the multiunit receptive field measured at the stimulation site. This kind of spatial specificity has also been observed in the middle temporal visual area (MT), but receptive fields in MST are typically much larger than those in MT. Thus MST microstimulation effects are characterized by a coarser spatial scale: stimulation of a single site in MST can influence judgements over a much larger portion of the visual field than equivalent stimulation in MT. 5. Microstimulation was often most effective when visual stimuli were placed within a particularly responsive subregion of the receptive field (a "hot spot"). 6. The results show that MST neurons, like MT neurons, can strongly influence performance on a direction discrimination task. Whether MT and MST influence the decision process in parallel or in series remains to be determined.
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Geng, Li, and Ke Zhang. "Correlation of Road Network Structure and Urban Mobility Intensity: An Exploratory Study Using Geo-Tagged Tweets." ISPRS International Journal of Geo-Information 12, no. 1 (December 28, 2022): 7. http://dx.doi.org/10.3390/ijgi12010007.
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Urban planners have been long interested in understanding how urban structure and activities are mutually influenced. Human mobility and economic activities naturally drive the formation of road network structure and the accessibility of the latter shapes the patterns of movement flow across urban space. In this paper, we perform an exploratory study on the relationship between the street network structure and the intensity of human movement in urban areas. We focus on two cities and we utilize a dataset of geo-tagged tweets that can form a proxy to urban mobility and the corresponding street networks as obtained from OpenStreetMap. We apply three network centrality measures, including closeness, betweenness and straightness centrality, calculated at a global or local scale, as well as under mixed or individual transportation mode (e.g., driving, biking and walking) with its directional accessibility, to uncover the structural properties of urban street networks. We further design an urban area transition network and apply PageRank to capture the intensity of human mobility. Our correlation analysis indicates different centrality metrics have different levels of correlation with the intensity of human movement. The closeness centrality consistently shows the highest correlation (with a coefficient around 0.6) with human movement intensity when calculated at a global scale, while straightness centrality often shows no correlation at the global scale or weaker correlation ρ≈0.4 at the local scale. The correlation levels further depend on the type of directional accessibility and of various types of transportation modes. Hence, the directionality and transportation mode, largely ignored in the analysis of road networks, are crucial. Furthermore, the strength of the correlation varies in the two cities examined, indicating potential differences in urban spatial structure and human mobility patterns.
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Horak, F. B., H. C. Diener, and L. M. Nashner. "Influence of central set on human postural responses." Journal of Neurophysiology 62, no. 4 (October 1, 1989): 841–53. http://dx.doi.org/10.1152/jn.1989.62.4.841.
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1. The effect of central set on automatic postural responses was studied in humans exposed to horizontal support-surface perturbations causing forward sway. Central set was varied by providing subjects with prior experience of postural stimulus velocities or amplitudes under 1) serial and random conditions, 2) expected and unexpected conditions, and 3) practiced and unpracticed conditions. In particular, the influence of central-set conditions was examined on the pattern and magnitude of six leg and trunk electromyograph (EMG) activations and associated ankle torque responses to postural perturbations with identical stimulus parameters. 2. The scaling of initial agonist integrated EMG (IEMG) and torque responses to postural perturbation amplitude disappeared when perturbation amplitudes were randomized. This finding suggests that the initial magnitude of postural responses were centrally set to anticipated postural perturbation amplitudes based on sequential experience with the stimulus. 3. Expectation of postural stimulus amplitude had a significant effect on initial torque responses; subjects overresponded when a larger perturbation was expected and underresponded when a smaller perturbation was expected. Expectation of postural stimulus velocity had a smaller effect on initial torque responses, and subjects consistently overresponded when the velocity of the perturbation was unexpected. This difference in amplitude and velocity expectation may be because of the capacity to encode stimulus velocity, but not amplitude information, into the earliest postural responses of the current trial. The relative strength of amplitude and velocity central-set effects varied widely with individual subjects. 4. Central-set conditions did not affect initial EMG response latencies (100 +/- 20 ms, mean +/- SD) or the relative onset of proximal and distal agonists and antagonists. Unexpected or unpracticed stimulus amplitudes, however, were associated with significant late activation of ankle antagonist, tibialis. Thus errors in initial response magnitude because of central-set effects appear to be partially corrected by reciprocal antagonist activity. Agonist IEMG, however, did not always reflect significant changes in torque responses with central-set conditions. 5. Expectation of postural stimulus amplitude and velocity had two different types of effects on the magnitudes of postural responses: 1) a directionally specific, central-set effect consisting of either increased or decreased responses, depending on expectation of stimulus amplitude; and 2) a nonspecific enhanced response to novel stimulus velocities with a gradual reduction when a velocity was presented repeatedly. Two different neural mechanisms are proposed for these two adaptive effects. 6. Reduction of postural response magnitude and antagonist activity during practice may be partially explained by adaptive mechanisms based on expectation because of prior experience with stimulus velocity and amp
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Mukhametrakhimov, Rustem, Albert Galautdinov, Polina Gorbunova, and Tatyana Gorbunova. "Water-resistant fiber-reinforced gypsum cement-pozzolanic composites." E3S Web of Conferences 138 (2019): 01011. http://dx.doi.org/10.1051/e3sconf/201913801011.
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Gypsum and gypsum-cement-pozzolanic composites are of significant interest as materials and products for building decoration. The current tendency to reduce the consumption of gypsum-based materials and products in the context of growth and development of the finishing materials market depends on the decrease in their competitiveness compared to peers. This leads to significant interest in improving the quality of products based on gypsum and gypsum-cement-pozzolanic binder. Dispersed reinforcement is one of the ways of improving performance characteristics. The role of the type of reinforcing fibers in the formation of the gypsum-cement-pozzolanic composites structure and properties is studied in article. The influence relations of the cellulose fibers content with varying grinding degrees on the relative flexural and compressive strength of a gypsum-cement-pozzolanic matrix are obtained. It was found that the optimal content of cellulose fibers in the modified gypsum-cement-pozzolanic matrix is 0.5-1% by weight of the binder, the best indicators of flexural and compressive strength are achieved by grinding cellulose fibers to 30°SR. Using scanning electron microscopy, it was found that the microstructure of a disperse-reinforced gypsum-cementpozzolanic matrix is characterized by a uniform cellulose fibers distribution, the predominance of directionally frame reinforcement with a fibers linear orientation in the sheet plane. In this way the right choice of the type, crushing degree and cellulose fibers content can improve the quality and expand the application area of the produced gypsum-cementpozzolanic composites.
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Vicary, Adam, William T. Roberts, and Donald V. Wilson. "Directionality of Yield Strength in Bakehardened Steels." International Journal of Materials Research 84, no. 10 (October 1, 1993): 702–7. http://dx.doi.org/10.1515/ijmr-1993-841009.
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Lotrecchiano, Gaetano R., Mary Kane, Mark S. Zocchi, Jessica Gosa, Danielle Lazar, and Jesse M. Pines. "Bringing voice in policy building." Leadership in Health Services 30, no. 3 (July 3, 2017): 272–308. http://dx.doi.org/10.1108/lhs-07-2016-0034.
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Purpose The purpose of this paper is to describe the use of group concept mapping (GCM) as a tool for developing a conceptual model of an episode of acute, unscheduled care from illness or injury to outcomes such as recovery, death and chronic illness. Design/methodology/approach After generating a literature review drafting an initial conceptual model, GCM software (CS Global MAXTM) is used to organize and identify strengths and directionality between concepts generated through feedback about the model from several stakeholder groups: acute care and non-acute care providers, patients, payers and policymakers. Through online and in-person population-specific focus groups, the GCM approach seeks feedback, assigned relationships and articulated priorities from participants to produce an output map that described overarching concepts and relationships within and across subsamples. Findings A clustered concept map made up of relational data points that produced a taxonomy of feedback was used to update the model for use in soliciting additional feedback from two technical expert panels (TEPs), and finally, a public comment exercise was performed. The results were a stakeholder-informed improved model for an acute care episode, identified factors that influence process and outcomes, and policy recommendations, which were delivered to the Department of Health and Human Services’s (DHHS) Assistant Secretary for Preparedness and Response. Practical implications This study provides an example of the value of cross-population multi-stakeholder input to increase voice in shared problem health stakeholder groups. Originality/value This paper provides GCM results and a visual analysis of the relational characteristics both within and across sub-populations involved in the study. It also provides an assessment of observational key factors supporting how different stakeholder voices can be integrated to inform model development and policy recommendations.
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Sancho, Rafael, Javier Segurado, Borja Erice, María-Jesús Pérez-Martín, and Francisco Gálvez. "Crystal-Plasticity-Finite-Element Modeling of the Quasi-Static and Dynamic Response of a Directionally Solidified Nickel-Base Superalloy." Materials 13, no. 13 (July 5, 2020): 2990. http://dx.doi.org/10.3390/ma13132990.
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The flow stress behaviour of a directionally solidified nickel-base superalloy, MAR-M247, is presented through the combination of experiments and crystal-plasticity simulations. The experimental campaign encompassed quasi-static and dynamic testing in the parallel and perpendicular orientation with respect to the columnar grains. The material showed low strain-rate sensitivity in all cases. Virtual samples were generated with DREAM3d and each grain orientation was established according to the DS nature of the alloy. The elasto-visco-plastic response of each crystal is given by phenomenological-base equations, considering the dislocation–dislocation interactions among different slip systems. The hardening-function constants and the strain-rate sensitivity parameter were fitted with the information from tests parallel to the grain-growth direction and the model was able to predict with accuracy the experimental response in the perpendicular direction, confirming the suitability of the model to be used as a tool for virtual testing. Simulations also revealed that in oligocrystalline structures of this type, the yield-strength value is controlled by the grains with higher Schmid factor, while this influence decreases when plastic strain increases. Moreover, the analysis of the micro-fields confirmed that grains perpendicular to the loading axis are prone to nucleate cavities since the stresses in these regions can be twice the external applied stress.
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Riley, Kevin E., and Khanh-An Tran. "Strength, character, and directionality of halogen bonds involving cationic halogen bond donors." Faraday Discussions 203 (2017): 47–60. http://dx.doi.org/10.1039/c7fd00106a.
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Halogen bonds involving cationic halogen bond donors and anionic halogen bond acceptors have recently been recognized as being important in stabilizing the crystal structures of many salts. Theoretical characterization of these types of interactions, most importantly in terms of their directionality, has been limited. Here we generate high-quality symmetry adapted perturbation theory potential energy curves of a H3N–CC–Br+⋯Cl− model system in order to characterize halogen bonds involving charged species, in terms of contributions from electrostatics, exchange, induction, and dispersion, with special emphasis on analyzing contributions that are most responsible for the directionality of these interactions. It is found that, as in the case of neutral halogen bonds, exchange forces are important contributors to the directionality of charged halogen bonds, however, it is also found that induction effects, which contribute little to the stability and directionality of neutral halogen bonds, play a large role in the directionality of halogen bonds involving charged species. Potential energy curves based on the ωB97X-D/def2-TZVP/C-PCM method, which includes an implicit solvation model in order to mimic the effects of the crystal medium, are produced for both the H3N–CC–Br+⋯Cl− model system and for the 4-bromoanilinium⋯Cl− dimer, which is based on the real 4-bromoanilinium chloride salt, whose crystal structure has been determined experimentally. It is found that, within a crystal-like medium, charged halogen bond are significantly weaker than in the gas phase, having optimum interaction energies up to approximately −20 kcal mol−1.
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Orth, Andreas, and Lorenz Ratke. "Effect of Travelling Magnetic Fields on the Dendritic Microstructure of AlSi and AlSiMn." Materials Science Forum 765 (July 2013): 235–40. http://dx.doi.org/10.4028/www.scientific.net/msf.765.235.
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The microstructure formation of AlSi alloys is known to be sensitive to specific solidification conditions. In particular, small fractions of heavier alloying atoms can lead to the precipitation of intermetallic phases. Moreover, the mainly dendritic structure is also sensitive to fluid flow in the melt. These two factors and their mutual influence is examined in this paper. The solidification of AlSi7 and AlSi7Mn1 samples was studied while inducing fluid flow by a traveling magnetic field (TMF) of approximately 5 mT strength, traveling up or down the sample axis. All samples were molten and directionally solidified at constant solidification velocities between 0.03 and 0.24 mm/s. The application of two separate heaters allowed the fixation of constant temperature gradients in the solid and liquid parts of the samples, the use of a transparent silica aerogel crucible permitted optical verification of the solidification velocity. Cross sections were cut from the processed samples and the microstructure analyzed using light microscopy and SEM-EDX. From these images, values for the primary, secondary and tertiary dendrite arm spacing were retrieved. Results are presented which show a clear effect of the TMF-induced fluid flow on the binary samples, but almost none for the ternary alloy. Finally, an explanation proposing a process of precipitate particle pushing is given.
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Calisti, Annette, Alexander Demura, Marco Gigosos, Diego González-Herrero, Carlos Iglesias, Valery Lisitsa, and Evgeny Stambulchik. "Influence of Microfield Directionality on Line Shapes." Atoms 2, no. 2 (June 19, 2014): 259–76. http://dx.doi.org/10.3390/atoms2020259.
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Trubenstein, Henry J., Shiva Moaven, Maythe Vega, Daniel K. Unruh, and Anthony F. Cozzolino. "Pnictogen bonding with alkoxide cages: which pnictogen is best?" New Journal of Chemistry 43, no. 36 (2019): 14305–12. http://dx.doi.org/10.1039/c9nj03648b.
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Dudev, Todor, Luis Manuel Frutos, and Obis Castaño. "How mechanical forces can modulate the metal affinity and selectivity of metal binding sites in proteins." Metallomics 12, no. 3 (2020): 363–70. http://dx.doi.org/10.1039/c9mt00283a.
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Poirier, Pierre, Frank K. Samson, and Thomas J. Imig. "Spectral Shape Sensitivity Contributes to the Azimuth Tuning of Neurons in the Cat's Inferior Colliculus." Journal of Neurophysiology 89, no. 5 (May 1, 2003): 2760–77. http://dx.doi.org/10.1152/jn.00640.2002.
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We recorded high-best-frequency single-unit responses to free-field noise bursts that varied in intensity and azimuth to determine whether inferior colliculus (IC) neurons derive directionality from monaural spectral-shape. Sixty-nine percent of the sample was directional (much more responsive at some azimuths than others). One hundred twenty-nine directional units were recorded under monaural conditions (unilateral ear plugging). Binaural directional (BD) cells showed weak monaural directionality. Monaural directional (MD) cells showed strong monaural directionality, i.e., were much more responsive at some directions than others. Some MD cells were sensitive to both monaural and binaural directional cues. MD cells were monaurally nondirectional in response to tone bursts that lack direction-dependent variation in spectral shape. MD cells were unresponsive to noise bursts at certain azimuths even at high intensities showing that particular spectral shapes inhibit their responses. Two-tone inhibition was stronger where MD cells were unresponsive to noise stimulation than at directions where they were responsive. According to the side-band inhibition model, MD cells derive monaural directionality by comparing energy in excitatory and inhibitory frequency domains and thus should have stronger inhibitory side-bands than BD cells. MD and BD cells showed differences in breadth of excitatory frequency domains, strength of nonmonotonic level tuning, and responsiveness to tones and noise that were consistent with this prediction. Comparison of these data with previous findings shows that strength of spectral inhibition increases greatly between the level of the cochlear nucleus and the IC, and there is relatively little change in strength of spectral inhibition among the IC, auditory thalamus, and cortex.
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Dev, Sagarika, Sudeep Maheshwari, and Angshuman Roy Choudhury. "Insights into the C–H⋯F–C hydrogen bond by Cambridge Structural Database analyses and computational studies." RSC Advances 5, no. 34 (2015): 26932–40. http://dx.doi.org/10.1039/c5ra03063c.
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Walker, Shane, and W. A. Kuperman. "The influence of ambient field directionality on wave coherence." Journal of the Acoustical Society of America 129, no. 4 (April 2011): 2627. http://dx.doi.org/10.1121/1.3588739.
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Tang, Qing Yuan, Wing Yin Tong, Jue Shi, Peng Shi, Yun Wah Lam, and Stella W. Pang. "Influence of engineered surface on cell directionality and motility." Biofabrication 6, no. 1 (March 4, 2014): 015011. http://dx.doi.org/10.1088/1758-5082/6/1/015011.
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Isyumov, Nicholas, Eric Ho, and Peter Case. "Influence of wind directionality on wind loads and responses." Journal of Wind Engineering and Industrial Aerodynamics 133 (October 2014): 169–80. http://dx.doi.org/10.1016/j.jweia.2014.06.006.
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Vugts, J. H. "Fatigue damage assessments and the influence of wave directionality." Applied Ocean Research 27, no. 3 (June 2005): 173–85. http://dx.doi.org/10.1016/j.apor.2005.11.003.
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Gil, Stephanie, Swarun Kumar, Dina Katabi, and Daniela Rus. "Adaptive communication in multi-robot systems using directionality of signal strength." International Journal of Robotics Research 34, no. 7 (May 18, 2015): 946–68. http://dx.doi.org/10.1177/0278364914567793.
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Luo, Pengjun, Hayato Asada, Chia-Ming Uang, and Tsuyoshi Tanaka. "Directionality Effect on Strength of Partial-Joint-Penetration Groove Weld Joints." Journal of Structural Engineering 146, no. 4 (April 2020): 04020030. http://dx.doi.org/10.1061/(asce)st.1943-541x.0002580.
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Kolář, Michal, Jiří Hostaš та Pavel Hobza. "Correction: The strength and directionality of a halogen bond are co-determined by the magnitude and size of the σ-hole". Physical Chemistry Chemical Physics 17, № 35 (2015): 23279–80. http://dx.doi.org/10.1039/c5cp90146d.
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Rosbottom, I., K. J. Roberts, and R. Docherty. "The solid state, surface and morphological properties of p-aminobenzoic acid in terms of the strength and directionality of its intermolecular synthons." CrystEngComm 17, no. 30 (2015): 5768–88. http://dx.doi.org/10.1039/c5ce00302d.
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The lattice energy and crystal morphologies of the α and β forms of p-aminobenzoic acid are correlated to experimentally grown crystals by calculating their strength, directionality and chemical state of their bulk (intrinsic) and surface (extrinsic) synthons.
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Goulart, Pedro R., J. E. Spinelli, F. Bertelli, Wislei R. R. Osório, Noé Cheung, and Amauri Garcia. "Cellular Microstructure and Mechanical Properties of a Directionally Solidified Al-1.0wt%Fe Alloy." Materials Science Forum 636-637 (January 2010): 564–70. http://dx.doi.org/10.4028/www.scientific.net/msf.636-637.564.
Повний текст джерелаАнотація:
Upward directional transient solidification experiments have been carried out with an Al-1.0wt%Fe alloy. Tensile tests were carried out with samples collected along the casting length and these results have been correlated with measured cell spacings, since cellular growth has prevailed along the directionally solidified casting. The resulting mechanical properties include ultimate tensile strength, yield tensile strength and elongation. The used casting assembly was designed in such a way that the heat was extracted only through the water-cooled system at bottom of the casting. During non-equilibrium solidification, typical of DC (direct chill) castings, different cooling rates occur from the casting cooled surface up to the top of the casting, causing the formation of metastable intermetallic phases (AlmFe, Al6Fe, etc) in addition to the stable Al3Fe phase. The extensive presence of plate-like Al3Fe phase in the as-cast structure adversely influences the mechanical properties of Al-Fe alloys, since this morphology is more likely to induce microcracks than the fibrous Al6Fe phase. In order to permit an appropriate characterization of these intermetallic phases, they were extracted from the aluminum-rich matrix by using a dissolution technique. These phases were then investigated by optical microscopy and SEM techniques. It was found that the ultimate tensile strength, the yield strength and the elongation increase with decreasing cell spacing and experimental laws correlating cell spacing and these mechanical properties have been established.
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Ilieva, Sonia, Diana Cheshmedzhieva, and Todor Dudev. "Electric field influence on the helical structure of peptides: insights from DFT/PCM computations." Physical Chemistry Chemical Physics 21, no. 29 (2019): 16198–206. http://dx.doi.org/10.1039/c9cp01542f.
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