Hierarchical Type Research Articles

Design and Fabrication of Bioinspired Hierarchical Dissipative Elastic Metamaterials

Hierarchical structures with constituents over multiple length scales are found in various natural materials like bones, shells, spider silk and others, all of which display enhanced quasi-static mechanical properties, such as high specific strength, stiffness and toughness. At the same time, the role of hierarchy on the dynamic behaviour of metamaterials remains largely unexplored. This study assesses the effect of bio-inspired hierarchical organization as well as of viscoelasticity on the wave attenuation properties of continuous mechanical metamaterials. We consider single-phase metamaterials formed by self-similar unit cells with different hierarchical levels and types of hierarchy. Results highlight a number of advantages through the introduction of structural hierarchy. Band gaps relative to the corresponding non-hierarchical structures are mostly preserved, while additional "hierarchically-induced" band gaps appear. Additionally, the hierarchical configuration allows the tuning of the band gap frequencies of regular metamaterial to lower frequencies, with a simultaneous significant reduction of the global structural weight. We show that even small viscoelastic effects, not treated in the current literature, are essential in determining this behaviour. The approach we propose allows the addition of hierarchical elements to existing metamaterial configurations, with the corresponding improvement of the wave damping properties, thus providing indications for the design of structures for practical applications.

Impact of organizational culture on quality management practices: an empirical investigation

PurposeThe purpose of this paper is to empirically examine the organizational culture (OC) of the competing values framework (CVF) on quality management (QM) practices. Specifically, it tests OC on two views, QM practices, i.e. the infrastructure quality and core QM practices.Design/methodology/approachThe proposed hypotheses were tested using empirical data drawn from 262 manufacturing organizations in India. The research model developed was analyzed using structural equation modeling technique.FindingsThe findings of this study revealed that the hierarchical and rational cultures are the dominant types of culture, and top management commitment and Six Sigma structure are the most important aspects of the infrastructure and core QM practices in Indian manufacturing organizations. Further, the results of the study showed that group culture and development culture are the most supportive culture types for both infrastructure and core QM practices. On the contrary, hierarchical and rational culture types are the least supportive for infrastructure and core QM practices. The study proposes the need for the mixed culture approach that facilitates the adoption of business strategiesPractical implicationsBefore implementing infrastructure and core QM practices, managers must understand the importance of cultural values in their organization to facilitate effective implementation of QM.Originality/valueThis paper contributes to the existing literature by providing empirical evidence leading to the relationship between OC and QM practices. This is the first study that empirically examined the Indian cultural context using CVF, thus contributing to the scarce body of literature particularly in the developing countries.

Hierarchical structure and the influence of individual attributes in the captive squirrel monkey (Saimiri collinsi)

The dominance structure of primate social groups varies widely. In addition to the groups' composition, intrinsic attributes such as sex, body size and life experience are important factors that can affect hierarchical dominance relations. All primates are social animals, and the social environment has a direct influence on the physiological conditions of vital systems such as immunological, reproductive and cardiovascular systems. In this study, we analyze the hierarchical structure of Saimiri collinsi in captivity, including the hierarchical structure type, the influence of individual intrinsic characteristics (sex, age, weight and origin-born in captivity or in the wild) based on the prior-attributes model, the relation between agonistic behavior frequency and hierarchical position, and hierarchy steepness, which represents the dominance gradient. We found that the group order was characterized by a partial hierarchy: a dominance position could be occupied by more than one individual simultaneously, including individuals of both sexes. Intrinsic characteristics had no influence on hierarchical structure, with the exception of the male in the highest hierarchical position, which had a markedly larger body than all other group members. Thus, the prior-attributes model did not apply to hierarchical formation of S. collinsi in captivity. Only the frequency of agonistic behavior of males correlated with their hierarchical position, and they differed from all other group members in their more aggressive behavior. The steepness between adjacent positions along the dominance gradient was significant only between the dominant male and the next individual in the group, with a smooth gradient between the other positions in the rank. As the access to resources is directly related to hierarchical dominance, a smooth dominance gradient is to be expected in species that form very large groups, such as wild Saimiri populations.

Self-assembled MXene-based nanocomposites via layer-by-layer strategy for elevated adsorption capacities

The chemical modification and organized self-assembly of MXene-based nanocomposites demonstrate critical importance to a wide range of material applications. Herein, we have investigated the preparation of new hierarchical core-shell type MXene-based composite materials for high-efficient dye removal in wastewater treatment via layer-by-layer (LbL) strategy. From the carboxyl functionalization of the MXene material, the negative functional groups were obtained on the surface of the shell composite layer. Carboxyl functionalized MXene materials are immersed in polyimide and polyacrylic acid solution respectively, which leads to formation of shell structure on the surface of MXene layer. Alternating self-assembly processes in the solutions of the polyimide and polyacrylic acid polymers are investigated until the desired number of shell layers is fabricated around MXene layer structures. Finally, the core-shell nanocomposites were characterized by morphological and spectral techniques, demonstrating that the core-shell nanocomposites have more reaction sites and mesoporous structures. The as-obtained core-shell nanocomposites were evaluated with well adsorption capacities via three kinds of dyes. Thus the study of MXene based composites assembled by LbL provides a new choice for the application of MXene composite nanomaterials in wastewater treatment.

Buckling strength topology optimization of 2D periodic materials based on linearized bifurcation analysis

Low density cellular materials may offer excellent mechanical properties and find wide applicability in lightweight design and infill structures for additive manufacturing, yet currently existing material structures are still far away from their theoretical limit in terms of compressive strength. To explore the existing potential, this paper presents a topology optimization framework for designing periodic cellular materials with maximized strength under compressive loading. Under this condition, the limiting factor of strength is the failure mechanism of buckling instability in the microstructure. In order to predict microstructural buckling, a simplified model based on homogenization theory, a linearized stability criterion and Floquet–Bloch theory is employed. Subsequently, a gradient-based topology optimization problem is formulated to maximize the buckling strength of the most critical failure mode. The framework is utilized to optimize square, triangular and hexagonal microstructures for three different macroscopic load conditions including biaxial, uniaxial and shear loading, and performance assessments are conducted by computation of associated failure surfaces in macroscopic stress space. In all cases, the optimized designs turn out to be first-order hierarchical type microstructures which offer major improvements of strength compared to the initial zero-order designs, however, the gains come at the cost of reductions in stiffness. Furthermore, it is illustrated how imposing geometric symmetry constraints can be exploited to control the shape of the failure surfaces.

Dynamics of Dust Particles of Different Structure: Application to the Modeling of Dust Motion in the Vicinity of the Nucleus of Comet 67P/Churyumov–Gerasimenko

We consider the estimates of the main forces acting on dust particles near a cometary nucleus. On the basis of these estimates, the motion of dust particles of different structure and mass is analyzed. We consider the following forces: (1) the cometary nucleus gravity, (2) the solar radiation pressure, and (3) the drag on dust particles by a flow of gas produced in the sublimation of cometary ice. These forces are important for modeling the motion of dust particles relative to the cometary nucleus and may substantially influence the dust transfer over its surface. In the simulations, solid silicate spheres and homogeneous ballistic aggregates are used as model particles. Moreover, we propose a technique to build hierarchic aggregates—a new model of quasi-spherical porous particles. A hierarchic type of aggregates makes it possible to model rather large dust particles, up to a millimeter in size and larger, while no important requirements for computer resources are imposed. We have shown that the properties of such particles differ from those of classical porous ballistic aggregates, which are usually considered in the cometary physics problems, and considering the microscopic structure of particles is of crucial significance for the analysis of the observational data. With the described models, we study the dust dynamics near the nucleus of comet 67P/Churyumov–Gerasimenko at an early stage of the Rosetta probe observations when the comet was approximately at 3.2 AU from the Sun. The interrelations between the main forces acting on dust aggregates at difference distances from the nucleus have been obtained. The dependence of the velocity of dust aggregates on their mass has been found. The numerical modeling results and the data of spaceborne observations with the Grain Impact Analyzer and Dust Accumulator (GIADA) and the Cometary Secondary Ion Mass Analyzer (COSIMA) onboard the Rosetta probe are compared at a quantitative level.

Hierarchical Type Stability Criteria for Delayed Neural Networks via Canonical Bessel-Legendre Inequalities.

This paper is concerned with global asymptotic stability of delayed neural networks. Notice that a Bessel-Legendre inequality plays a key role in deriving less conservative stability criteria for delayed neural networks. However, this inequality is in the form of Legendre polynomials and the integral interval is fixed on . As a result, the application scope of the Bessel-Legendre inequality is limited. This paper aims to develop the Bessel-Legendre inequality method so that less conservative stability criteria are expected. First, by introducing a canonical orthogonal polynomial sequel, a canonical Bessel-Legendre inequality and its affine version are established, which are not explicitly in the form of Legendre polynomials. Moreover, the integral interval is shifted to a general one . Second, by introducing a proper augmented Lyapunov-Krasovskii functional, which is tailored for the canonical Bessel-Legendre inequality, some sufficient conditions on global asymptotic stability are formulated for neural networks with constant delays and neural networks with time-varying delays, respectively. These conditions are proven to have a hierarchical feature: the higher level of hierarchy, the less conservatism of the stability criterion. Finally, three numerical examples are given to illustrate the efficiency of the proposed stability criteria.

An a posteriori error estimator for a LPS method for Navier–Stokes equations

In this work we develop an a posteriori error estimator, of the hierarchical type, for the Local Projection Stabilized (LPS) finite element method introduced in [5], applied to the incompressible Navier–Stokes equations. The technique uses the solution of locals problems posed on appropriate finite dimensional spaces of bubble-like functions, to approach the error. Several numerical tests confirm the theoretical properties of the estimator and its performance.

An organizational culture for all seasons? How cultural type dominance and strength influence different performance goals

ABSTRACTOrganizational culture might influence results, especially in public healthcare organizations characterized by strong professional control. This study investigates whether a specific culture type is most effective in fostering performances. We assess organizational culture through Competing Values Framework and use multivariate regression analysis to test the relationship between dominant culture and competitiveness and financial results. Based on 529 responses from senior managers of 59 organizations, we found that dominant rational and hierarchical culture types are associated, respectively, with higher competitiveness and better financial results. Enhancing a specific performance dimension might require cultural changes aimed to align values with targeted results.

Productive performance, technology heterogeneity and hierarchies: Who to compare with whom

In this paper we argue that inappropriate handling of technological heterogeneity distorts the benchmarking process eroding performance scores. Country- and industry-specific frontier studies have been the dominant approaches in explaining productivity differentials stating that heterogeneous performance patterns are attributed to different sources. However, studies bringing together the above approaches have not been surfaced yet. We fill that void by partitioning the metafrontier to account for alternative technological hierarchies. To disentangle the layers of complexity triggering heterogeneous performance, we introduce two types of heterogeneity each one referring to different stages of the performance evaluation process. To identify the Decision making unit-Specific Heterogeneity type, attached to each entity, we propose the w-ratio as a result of an iterative algorithm developed herein. In order to identify the Hierarchical Structural Heterogeneity type arising under alternative hierarchical structures, we define thresholds of heterogeneity. Using data on seventeen European countries and thirteen industries from manufacturing and transportation from 1999 through 2006 and employing a control function approach with one endogenous covariate, we find that the DSH and the HSH type are endogenously related via the role of the state dependence while the path dependence phenomenon is a major catalyst for future technological achievements and productivity improvements. Transition economies and fragmented industries exhibit persistent technological heterogeneity regardless of the technological structure adopted, since further development is mostly affected by past characteristics of the economic environment implying low subsequent competitiveness.

МЕХАНІЗМ ЗАБЕЗПЕЧЕННЯ ЕКОНОМІЧНОЇ БЕЗПЕКИ РЕГІОНУ: СУТНІСТЬ, СКЛАДОВІ, НАПРЯМИ ДІЇ

The essence of the concept of «security of the region» is discussed. It substantiates the role and importance of economic security in the processes of regional development. Basic subsystems of economic security within the hierarchical structure of the security system are outlined. Decomposition of levels and kinds within the category of «economic security» is carried out. Indicators for determination of number of hierarchical levels and types of economic security at each level under conditions of globalization are defined. The evaluation of the security of the country was conducted. It revealed the regions that are in a state of safety and danger. Regional features of social and economical development are determined. Various between social and economical development of regions in their safety are shown. The mechanisms to ensure security of the country regions were suggested.

Three-layer granular structures and three-way informational measures of a decision table

Attribute reduction in rough set theory serves as a fundamental topic for information processing, and its basis is usually a decision table (D-Table). D-Table attribute reduction concerns three hierarchical types, and only classification-based reduction is related to information-theoretic representation. Aiming at inducing comprehensive D-Table attribute reduction with hierarchies and information, this paper concretely constructs a D-Table’s three-layer granular structures and three-way informational measures via granular computing and Bayes’ theorem. With regard to the D-Table, the micro-bottom, meso-middle, and macro-top are hierarchically organized according to the formal structure and systematic granularity. Then, different layers produce different three-way informational measures by developing Bayes’ theorem. Thus, three-way weighted entropies originate from three-way probabilities at the micro-bottom and further evolve from the meso-middle to the macro-top, and their granulation monotonicity and evolution systematicness are acquired. Furthermore, three-way informational measures are analyzed by three-layer granular structures to achieve their hierarchical evolution, superiority, and algorithms. Finally, structural and informational results are effectively illustrated by a D-Table example. This study establishes D-Table’s hierarchical structures to reveal constructional mechanisms and systematic relationships of informational measures. The obtained results underlie the D-Table’s hierarchical, systematic, and informational attribute reduction, and they also enrich the three-way decisions theory.

Ordering the mob: Insights into replicon and MOB typing schemes from analysis of a curated dataset of publicly available plasmids

Plasmid typing can provide insights into the epidemiology and transmission of plasmid-mediated antibiotic resistance. The principal plasmid typing schemes are replicon typing and MOB typing, which utilize variation in replication loci and relaxase proteins respectively. Previous studies investigating the proportion of plasmids assigned a type by these schemes (‘typeability’) have yielded conflicting results; moreover, thousands of plasmid sequences have been added to NCBI in recent years, without consistent annotation to indicate which sequences represent complete plasmids. Here, a curated dataset of complete Enterobacteriaceae plasmids from NCBI was compiled, and used to assess the typeability and concordance of in silico replicon and MOB typing schemes. Concordance was assessed at hierarchical replicon type resolutions, from replicon family-level to plasmid multilocus sequence type (pMLST)-level, where available. We found that 85% and 65% of the curated plasmids could be replicon and MOB typed, respectively. Overall, plasmid size and the number of resistance genes were significant independent predictors of replicon and MOB typing success. We found some degree of non-concordance between replicon families and MOB types, which was only partly resolved when partitioning plasmids into finer-resolution groups (replicon and pMLST types). In some cases, non-concordance was attributed to ambiguous boundaries between MOBP and MOBQ types; in other cases, backbone mosaicism was considered a more plausible explanation. β-lactamase resistance genes tended not to show fidelity to a particular plasmid type, though some previously reported associations were supported. Overall, replicon and MOB typing schemes are likely to continue playing an important role in plasmid analysis, but their performance is constrained by the diverse and dynamic nature of plasmid genomes.

La Influencia de la Cultura Empresarial en el Rendimiento de la Pyme de México

In the current literature on business and management sciences, researchers, academics and professionals have focused on the publication of theoretical and empirical research on the development and importance of organizational culture in companies, but relatively few have And studies on the relationship between entrepreneurial culture and corporate performance, and even more scanty are the theoretical and empirical studies that analyze these two constructs in an environment of small and medium-sized enterprises (SMEs). The objective of this paper is to study the effect that business culture has on the level of performance of SMEs in the State of Aguascalientes, using a sample of 400 SMEs based in this geographical location. The results show that the business culture (clan, adhocratic and market) have a strong influence on the level of SMEs performance, but not hierarchical type culture.

Between Oil and Reindeer. Benefit Sharing Agreements between Oil Companies and Indigenous People in Russian Arctic and Subarctic Regions

This research provides insight into various modes of benefit-sharing agreements between oil and gas companies and indigenous people in the Russian Arctic and Subarctic regions. We indicate three main modes of benefit sharing, as follows: (1) paternalism, (2) corporate social responsibility, and (3) partnership. The paternalistic mode is characterized by a hierarchical type of interaction, which implies a patron and clients. This system of obligations is based on practices of informal interaction, and the decision-making process is neither formal, nor transparent. The mode of corporate social responsibility aims to raise investment attractiveness and the productive efficiency of the company, supporting its image as a socially responsible operator. In this mode, the key decisions are made by the company executives in view of state legislation, corporate policies, international standards, and investors’ demands. Finally, the partnership mode suggests equal opportunities for dialogue and decision making for all sides involved - the state authorities, companies, local people, and experts. It is based on global standards that protect the rights of local indigenous communities. This work examines the factors that influence those modes and their efficiency. It asks what is most important in their making: Is it regional specifics, dependency from international actors, details of corporate policies, or the level of local community organization? What instruments of benefit sharing turn out to be most favorable in the Russian context? Our research was conducted using qualitative research methods in three regions of Russia (Nenets Autonomous Okrug [NAO], Khanty-Mansi Autonomous Okrug, and Sakhalin). The article is based on the materials of several field expeditions to NAO in 2011 and 2017, Khanty-Mansi Autonomous Okrug in 2014, and Sakhalin in 2013 and 2015. The main sources for analysis were interviews with representatives of oil companies, authorities, indigenous peoples, and the expert community. A total of 130 semi-structured interviews were conducted. In addition, we used materials from observation and document analysis (Russian legislation, international standards, and corporate reports).

Interactive cooperation and hierarchical operation of microRNA and transcription factor crosstalk in human transcriptional regulatory network.

Transcriptional regulation of gene expression is an essential cellular process that is arranged by transcription factors (TFs), microRNAs (miRNA) and their target genes through a variety of mechanisms. Here, we set out to reconstruct a comprehensive transcriptional regulatory network of Homo sapiens consisting of experimentally verified regulatory information on miRNAs, TFs and their target genes. We have performed topological analyses to elucidate the transcriptional regulatory roles of miRNAs and TFs. When we thoroughly investigated the network motifs, different gene regulatory scenarios were observed; whereas, mutual TF-miRNA regulation (interactive cooperation) and hierarchical operation where miRNAs were the upstream regulators of TFs came into prominence. Otherwise, biological process specific subnetworks were also constructed and integration of gene and miRNA expression data on ovarian cancer was achieved as a case study to observe dynamic patterns of the gene expression. Meanwhile, both co-operation and hierarchical operation types were determined in active ovarian cancer and process-specific subnetworks. In addition, the analysis showed that multiple signals from miRNAs were integrated by TFs. Our results demonstrate new insights on the architecture of the human transcriptional regulatory network, and here we present some lessons we gained from deciphering the reciprocal interplay between miRNAs, TFs and their target genes.

Cultural influences on attitudes about the causes and consequences of wildlife poaching

The extant poaching literature has been criticized as an overly static way of profiling offenders and predicting crime, since the categorization of environmental crime is contingent on the social context as much as offender motivations. Cultural factors have the potential to affect both poaching practices and societal responses to poaching. Cultural risk theory proposes that risk perceptions are shaped by two dimensions: the level of affiliation between individuals (group) and the prescriptiveness of norms (grid). Using quantitative survey data (N = 49) from stakeholders living near Analamazaotra Special Reserve in Madagascar (2013), we analyzed how prescriptiveness of norms at different levels of affiliation affected motivations to poach and not to poach and perceived impacts of poaching on people and the environment. Malagasy laws were a more significant deterrent to poaching than fokonolona rules. The pre-colonial fokonolona was consistent with an equalitarian cultural type and influenced beliefs about the human consequences of poaching, whereas the post-colonial Madagascar National Parks adhered to a hierarchical cultural type and had a robust effect on the perceived environmental impacts of poaching. Implications for environmental crime in Madagascar and cultural risk theory are discussed.

Directly grown TiO2 nanotubes on carbon nanofibers for photoelectrochemical water splitting

ABSTRACTA variety of Titanium dioxide (TiO2) phases and nanostructures have been explored for their applications in photoelectrochemical cells (PECs) for solar-driven water splitting. In this case, anatase phase and TiO2 nanotubes offer significant advantages especially for PEC-based applications. Though, significant efforts have already been engaged to combine the advantages from both the fields, poor activation and the high electron-hole pair recombination rate of TiO2 electrodes, originating from intrinsic physicochemical properties, limits its practical use. As an alternative, we report directly grown TiO2 nanotubes (synthesized on Fluorine doped Tin Oxide (FTO) via facile electrospinning technique) on carbon nanofibers, using hydrothermal method. The hierarchical branch type configuration has an intimate contact between the TiO2 nanotube and carbon nanofiber backbone and offers higher photocatalytic activity than their respective individual components (namely TiO2 nanotubes and carbon nanostructures).

MHD flow due to a linearly stretching sheet with induced magnetic field

The full MHD equations, governing the flow due to a linearly stretching sheet in the presence of a transverse magnetic field, can be cast in a self similar form involving two parameters—the magnetic Prandtl number \(P_\mathrm{m} \) and the magnetic interaction number \(\beta \). The leading-order problem, as \(P_\mathrm{m} \sim 0\), is of hierarchical type allowing the solution first for the velocity field and then for the induced magnetic field. Solutions of the full problem tend readily to the hierarchical solutions as \(P_\mathrm{m} \) gets smaller, thus justifying the use of the hierarchical approach even at not so small \(P_\mathrm{m}\).

A qualitative study of nurse practitioner promotion of interprofessional care across institutional settings: Perspectives from different healthcare professionals

ObjectiveInterprofessional care, an aim of institutional healthcare settings globally, promotes safe, cost-effective, quality care. How professionals act to enable interprofessional care has not been described. The nurse practitioner role, with its expertise in both medicine and nursing, is known to enhance collaboration and promote interprofessional care delivery. The objective of this study was to identify, from the healthcare professionals' perspective, nurse practitioner strategies used to enhance interprofessional care. MethodA hermeneutic phenomenology design was employed. Healthcare professionals from acute care hospitals and associated long-term care residences (n = 6) in one Canadian province were invited to participate. Individual interviews were held with healthcare professionals (n = 52) who regularly work with a nurse practitioner. The participants were asked to share experiences that held significance or value in promoting interprofessional care. ResultsFour valued role attributes were identified; consistent role presence, time to focus on the patient, effective communication, and respectful centrality. Identified strategies extending from the attributes included knowledge sharing, respectful negotiation, identifying patient issues, being open and transparent, listening to opinions, bridging professions, and working as the hub of the group. Multiple types of interprofessional relationships were perceived, with the hierarchical type as the most common. ConclusionsNurse practitioners in acute care hospital and long-term care settings have valued attributes that can promote interprofessional care. Effective strategies to promote interprofessional care emerge from these role attributes. However, the interprofessional relationship type perceived could enhance or impede the contribution of the strategies to interprofessional care promotion.