scholarly journals Mechanisms underlying higher order interactions: from quantitative definitions to ecological processes

2019 ◽  
Author(s):  
Andrew R. Kleinhesselink ◽  
Nathan J.B. Kraft ◽  
Jonathan M. Levine
Keyword(s):  
Empirical Data ◽  
Resource Competition ◽  
Higher Order ◽  
General Definition ◽  
Emergent Properties ◽  
Size Change ◽  
Ecological Processes ◽  
Competition Models ◽  
Wide Range ◽  
Annual Plant Species

AbstractWhen species simultaneously compete with two or more species of competitor, higher order interactions (HOIs) can lead to emergent properties not present when species interact in isolated pairs. In order to extend ecological theory to multi-competitor communities, ecologists must develop a practical and general definition for HOIs that can be applied to a wide range of competition models. In this paper we propose a definition for HOIs and outline a set of criteria for testing whether a model has or does not have HOIs. These criteria are valuable for empirical ecologists in need of clarity when discussing HOIs in empirical data. We also provide thorough discussion of how our definition compares with previous definitions of HOIs and interaction modification in the literature. In the second part of the paper we demonstrate the steps required for a rigorous test of HOIs in empirical data. To do this we simulate resource competition between three annual plant species which differ in phenology. We then fit phenomenological competition models to the outcome of simulated competition and use these to test for the presence of HOIs. In our simulations, we find the strength of HOIs varies with phenology: species that grow later experience stronger HOIs than earlier growing species. Our simulation shows how HOIs could emerge in ecosystems where resource availability and individual size change rapidly throughout the course of the growing season and where there are differences in the timing of resource acquisition between competitors.

Current Trends in Biotherapeutic Higher Order Structure Characterization by Irreversible Covalent Footprinting Mass Spectrometry

2019 ◽  
Vol 26 (1) ◽  
pp. 35-43 ◽  
Author(s):  
Natalie K. Garcia ◽  
Galahad Deperalta ◽  
Aaron T. Wecksler
Keyword(s):  
Mass Spectrometry ◽  
Protein Structure ◽  
Protein Interactions ◽  
Quaternary Structure ◽  
Solvent Accessibility ◽  
Higher Order ◽  
Structure Characterization ◽  
Order Structure ◽  
Protein Footprinting ◽  
Wide Range

Background: Biotherapeutics, particularly monoclonal antibodies (mAbs), are a maturing class of drugs capable of treating a wide range of diseases. Therapeutic function and solutionstability are linked to the proper three-dimensional organization of the primary sequence into Higher Order Structure (HOS) as well as the timescales of protein motions (dynamics). Methods that directly monitor protein HOS and dynamics are important for mapping therapeutically relevant protein-protein interactions and assessing properly folded structures. Irreversible covalent protein footprinting Mass Spectrometry (MS) tools, such as site-specific amino acid labeling and hydroxyl radical footprinting are analytical techniques capable of monitoring the side chain solvent accessibility influenced by tertiary and quaternary structure. Here we discuss the methodology, examples of biotherapeutic applications, and the future directions of irreversible covalent protein footprinting MS in biotherapeutic research and development. Conclusion: Bottom-up mass spectrometry using irreversible labeling techniques provide valuable information for characterizing solution-phase protein structure. Examples range from epitope mapping and protein-ligand interactions, to probing challenging structures of membrane proteins. By paring these techniques with hydrogen-deuterium exchange, spectroscopic analysis, or static-phase structural data such as crystallography or electron microscopy, a comprehensive understanding of protein structure can be obtained.

scholarly journals Revisiting the Functional Zoning Concept under Climate Change to Expand the Portfolio of Adaptation Options

Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 273
Author(s):  
Samuel Royer-Tardif ◽  
Jürgen Bauhus ◽  
Frédérik Doyon ◽  
Philippe Nolet ◽  
Nelson Thiffault ◽  
...  
Keyword(s):  
Climate Change ◽  
Multiple Use ◽  
Management Options ◽  
Ecological Processes ◽  
Adaptation Measures ◽  
Good Communication ◽  
Management Objectives ◽  
Functional Zoning ◽  
Wide Range ◽  
Adaptation Options

Climate change is threatening our ability to manage forest ecosystems sustainably. Despite strong consensus on the need for a broad portfolio of options to face this challenge, diversified management options have yet to be widely implemented. Inspired by functional zoning, a concept aimed at optimizing biodiversity conservation and wood production in multiple-use forest landscapes, we present a portfolio of management options that intersects management objectives with forest vulnerability to better address the wide range of goals inherent to forest management under climate change. Using this approach, we illustrate how different adaptation options could be implemented when faced with impacts related to climate change and its uncertainty. These options range from establishing ecological reserves in climatic refuges, where self-organizing ecological processes can result in resilient forests, to intensive plantation silviculture that could ensure a stable wood supply in an uncertain future. While adaptation measures in forests that are less vulnerable correspond to the traditional functional zoning management objectives, forests with higher vulnerability might be candidates for transformative measures as they may be more susceptible to abrupt changes in structure and composition. To illustrate how this portfolio of management options could be applied, we present a theoretical case study for the eastern boreal forest of Canada. Even if these options are supported by solid evidence, their implementation across the landscape may present some challenges and will require good communication among stakeholders and with the public.

A Parallel HOFD Scheme for Direct Numerical Simulation of Turbulent Magnetically Driven Flows

2001 ◽  
Author(s):  
X. Ai ◽  
B. Q. Li
Keyword(s):  
Numerical Simulation ◽  
Finite Difference ◽  
Direct Numerical Simulation ◽  
Turbulent Flows ◽  
Parallel Machines ◽  
Higher Order ◽  
Electrically Conducting ◽  
Wide Range ◽  
Order Scheme ◽  
Higher Order Scheme

Abstract Turbulent magnetically flows occur in a wide range of material processing systems involving electrically conducting melts. This paper presents a parallel higher order scheme for the direct numerical simulation of turbulent magnetically driven flows in induction channels. The numerical method is based on the higher order finite difference algorithm, which enjoys the spectral accuracy while minimizing the computational intensity. This, coupled with the parallel computing strategy, provides a very useful means to simulate turbulent flows. The higher order finite difference formulation of magnetically driven flow problems is described in this paper. The details of the parallel algorithm and its implementation for the simulations on parallel machines are discussed. The accuracy and numerical performance of the higher order finite difference scheme are assessed in comparison with the spectral method. The examples of turbulent magnetically driven flows in induction channels and pressure gradient driven flows in regular channels are given, and the computed results are compared with experimental measurements wherever possible.

scholarly journals Traits and values as predictors of the frequency of everyday behavior: Comparison between models and levels

2018 ◽  
Vol 40 (1) ◽  
pp. 133-153 ◽  
Author(s):  
Ewa Skimina ◽  
Jan Cieciuch ◽  
Włodzimierz Strus
Keyword(s):  
Personality Traits ◽  
Factor Model ◽  
Five Factor Model ◽  
Personal Values ◽  
Derived Categories ◽  
Higher Order ◽  
Behavioral Factors ◽  
Wide Range ◽  
Age Range ◽  
Hexaco Model

AbstractThe aims of this study were to compare (a) personality traits vs personal values, (b) Five-Factor Model (FFM) vs HEXACO model of personality traits, and (c) broad vs narrow personality constructs in terms of their relationship with the frequency of everyday behaviors. These relationships were analyzed at three organizational levels of self-reported behavior: (a) single behavioral acts, (b) behavioral components (empirically derived categories of similar behaviors), and (c) two higher-order factors. The study was conducted on a Polish sample (N = 532, age range 16–72). We found that (a) even the frequencies of single behavioral acts were related to various personality constructs instead of one narrow trait or value, (b) personality traits and personal values were comparable as predictors of a wide range of everyday behaviors, (c) HEXACO correlated with the frequency of behaviors slightly higher than FFM, and (d) narrow and broad personality constructs did not differ substantially as predictors of everyday behavior at the levels of acts and components, but at the level of higher-order behavioral factors, broad personality measures were better predictors than narrow ones.

Three Frontiers of the Southern Yucatán Peninsular Region and SYPR Project

2004 ◽  
Author(s):  
B. L. Turner II ◽  
D. R. Foster
Keyword(s):  
Immanuel Kant ◽  
Geographical Information Systems ◽  
Global Climate ◽  
Global Environmental Change ◽  
Geographical Information ◽  
Emergent Properties ◽  
Land Change ◽  
Ecosystem Integrity ◽  
Change Models ◽  
Wide Range

Frontiers advance and retreat, both figuratively and literally. At this moment they are advancing in three ways relevant to the subject of this book and the ongoing project on which it is based. First, after more than a century of reductionist hegemony, various science communities worldwide increasingly recognize the need to improve complementary, synthesis understanding—a way of putting the reductionist pieces of the problem back together again in order to understand how the ‘whole’ system works and to identify the emergent properties that follow from the complex interactions of the pieces. Synthesis understanding is not, of course, new. In the late eighteenth century, Immanuel Kant argued for it as one of the pillars of science in the reorganization of knowledge in the European academy (Turner 2002a) and designated geography as one of the ‘synthesis sciences’. Its contemporary rediscovery, however, rests in the science of global environmental change (Lawton 2001; Steffen et al. 2002), especially efforts to model complex systems, such as those in ocean–atmosphere–land interactions, and has been expanded by emerging research agendas seeking to couple human and environment systems, often registered under the label of ‘sustainability science’ (e.g. Kates et al. 2001; NRC 1999). Second, within these developments landuse and land-cover change (or, simply, land change) is singled out because of its centrality to a wide range of environmental concerns, including global climate change, regional–local hydrological impacts, biodiversity, and, of course, human development and ecosystem integrity (e.g. Brookfield 1995; NRC 2000; Watson et al. 2001). The need to advance an integrated land-change science is also increasingly recognized, one in which human, ecological, and remote sensing and geographical information systems (GIS) sciences are intertwined in problem-solving (Liverman et al. 1998; Klepeis and Turner 2001; Turner 2002b). And central to this effort is the need to advance geographically (spatially) explicit land-change models that can explain and project coupled human-ecological systems, and thus serve a wide range of research and assessment constituencies, from carbon to biodiversity to human vulnerability (IGBP 1999; Irwin and Geoghegan 2001; Kates et al. 2001; Liverman et al. 1998; Veldkamp and Lambin 2001). These two developments—synthesis science and integrated land science directed towards geographically explicit land-change models—constitute the broader intellectual and research frontiers to which this work contributes.

Landscape Heterogeneity and Dynamics

2019 ◽  
pp. 42-126
Author(s):  
Kimberly A. With
Keyword(s):  
Landscape Ecology ◽  
Spatial Heterogeneity ◽  
Landscape Structure ◽  
Landscape Heterogeneity ◽  
Spatial Scales ◽  
Anthropogenic Disturbances ◽  
Ecological Processes ◽  
Disturbance Dynamics ◽  
Wide Range ◽  
Over Time

Heterogeneity is a defining characteristic of landscapes and therefore central to the study of landscape ecology. Landscape ecology investigates what factors give rise to heterogeneity, how that heterogeneity is maintained or altered by natural and anthropogenic disturbances, and how heterogeneity ultimately influences ecological processes and flows across the landscape. Because heterogeneity is expressed across a wide range of spatial scales, the landscape perspective can be applied to address these sorts of questions at any level of ecological organization, and in aquatic and marine systems as well as terrestrial ones. Disturbances—both natural and anthropogenic—are a ubiquitous feature of any landscape, contributing to its structure and dynamics. Although the focus in landscape ecology is typically on spatial heterogeneity, disturbance dynamics produce changes in landscape structure over time as well as in space. Heterogeneity and disturbance dynamics are thus inextricably linked and are therefore covered together in this chapter.

Effect of Ratio of Liquid Pigment on Colouring Cement Matrix

2019 ◽  
Vol 296 ◽  
pp. 3-8
Author(s):  
David Bujdoš ◽  
Lucia Bulíková
Keyword(s):  
Colour Change ◽  
High Ratio ◽  
General Definition ◽  
Cement Matrix ◽  
Future Research ◽  
Colour Space ◽  
Cement Mortars ◽  
Wide Range ◽  
Definition Of ◽  
Cie Lab

Nowadays, the colouring is used in wide range of architectural concrete. Therefore, determination efficiency of pigments in case of particular combination of input materials is necessary. The research deals with influence of concentration of liquid inorganic pigments on the resulting colour of cement mortars. Two liquid pigments (yellow, red) were used for measurement purposes to verify their optimal ratio to achieve the best colouring of cement specimens. Pigments were mixed in the mortars of two types of cements used for architectural and decorative design. The colour change was determined using Konica Minolta spectrophotometer in colour space CIE Lab (1976). General definition of deviation in the colour space ΔELab was applied for calculating of colour deviation. From the results of the laboratory tests is obvious that significant change of the colour of cement specimens do not show between the concentration of 6% and 9% of the pigment per cement weight yet. Consequently, using of high ratio of pigment than 9% is not profitable neither for purchaser, nor builder. Future research will focus on trials with a more elaborate share of pigment and it will have importance for price optimization in the construction industry.

Rewilding

Ecology ◽  
2019 ◽  
Author(s):  
Meredith Root-Bernstein
Keyword(s):  
The United States ◽  
Large Species ◽  
Large Carnivores ◽  
Apex Predators ◽  
Ecological Processes ◽  
Large Herbivore ◽  
Large Herbivores ◽  
True Nature ◽  
The Public ◽  
Wide Range

Rewilding is an increasingly recognized approach to conservation and restoration, among academics, land managers, and the public. Although a number of different definitions have been proposed for rewilding (see Definitions of Rewilding), most approaches called “rewilding” include ideas about restoring a habitat to a less-anthropogenic state, restoring ecological processes and allowing them to take their own course without managing for a target ecosystem condition and (re)-introducing missing (usually large) species as a way to restore those ecological processes. Conceptualizations of rewilding and actual rewilding projects draw on a wide range of cultural and ecological ideas and practical knowledge, which are detailed in this article. Several organizations now represent rewilding interests to policymakers and the public and set up or facilitate rewilding initiatives in Europe and the Americas. Much of their philosophies, practice, data, and outcomes are not published. The Wildland Research Institute is an influential source of research on wilderness mapping, rewilding, restoration, and policy analysis in Europe. The European Centre for Nature Conservation (ECNC) supports and facilitates the conservation of large herbivore populations and their habitats at large scales in Eurasia through its Large Herbivore Network. Rewilding Europe implements rewilding projects throughout Europe, bringing together financing for large herbivore reintroductions and luxury wilderness tourism. Their European Rewilding Network brings together rewilding-related services and knowledge exchange. Similarly, the True Nature Foundation is a European foundation that works to restore habitats, reintroduce primarily large herbivores, and create sustainable tourism in nature areas. Wild Europe seeks to promote and lobby for the protection of large, “wild” natural areas. Similarly, the European Wilderness Society is an advocacy organization that identifies and promotes the stewardship and protection of large wilderness areas. The Rewilding Foundation is an international organization promoting and working toward the conservation of large areas of habitat and corridors for large carnivores. The Wildlands Network is an American organization that similarly seeks to conserve and connect large habitat areas and reintroduce apex predators. The Rewilding Institute in the United States also promotes protecting large habitats and creating corridors for large carnivores. There are also numerous site-based rewilding projects, which largely preceded the consolidation of rewilding as a concept. Many of these, through their creative rethinking of ecological and paleo-ecological orthodoxy, have influenced the development of rewilding practice and theory.

scholarly journals Non-Abelian Bloch oscillations in higher-order topological insulators

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
M. Di Liberto ◽  
N. Goldman ◽  
G. Palumbo
Keyword(s):  
Quantum Dynamics ◽  
Topological Insulators ◽  
Berry Phase ◽  
Center Of Mass ◽  
Higher Order ◽  
Topological Properties ◽  
Bloch Oscillations ◽  
Abelian Gauge ◽  
Synchronization Mechanism ◽  
Wide Range

AbstractBloch oscillations (BOs) are a fundamental phenomenon by which a wave packet undergoes a periodic motion in a lattice when subjected to a force. Observed in a wide range of synthetic systems, BOs are intrinsically related to geometric and topological properties of the underlying band structure. This has established BOs as a prominent tool for the detection of Berry-phase effects, including those described by non-Abelian gauge fields. In this work, we unveil a unique topological effect that manifests in the BOs of higher-order topological insulators through the interplay of non-Abelian Berry curvature and quantized Wilson loops. It is characterized by an oscillating Hall drift synchronized with a topologically-protected inter-band beating and a multiplied Bloch period. We elucidate that the origin of this synchronization mechanism relies on the periodic quantum dynamics of Wannier centers. Our work paves the way to the experimental detection of non-Abelian topological properties through the measurement of Berry phases and center-of-mass displacements.

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