scholarly journals An update on passive transport in and out of plant cells

2021 ◽  
Author(s):  
Melissa Tomkins ◽  
Nathan Hughes ◽  
Richard J Morris
Keyword(s):  
Driving Forces ◽  
Transport Processes ◽  
Passive Transport ◽  
Plant Growth And Development ◽  
Levels Of Abstraction ◽  
Open Questions ◽  
Flow Transport ◽  
Recent Developments ◽  
Physical Forces ◽  
Different Levels

Abstract Transport across membranes is critical for plant survival. Membranes are the interfaces at which plants interact with their environment. The transmission of energy and molecules into cells provides plants with the source material and power to grow, develop, defend, and move. An appreciation of the physical forces that drive transport processes is thus important for understanding plant growth and development. We focus on the passive transport of molecules, describing the fundamental concepts and demonstrating how different levels of abstraction can lead to different interpretations of the driving forces. We summarise recent developments on quantitative frameworks for describing diffusive and bulk flow transport processes in and out of cells, with a more detailed focus on plasmodesmata, and outline open questions and challenges.

scholarly journals Model-Driven Architectural Framework towards Safe and Secure Nuclear Power Reactors

Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 5136
Author(s):  
Bassem Ouni ◽  
Christophe Aussagues ◽  
Saadia Dhouib ◽  
Chokri Mraidha
Keyword(s):  
Nuclear Power ◽  
Nuclear Reactors ◽  
System Development ◽  
Levels Of Abstraction ◽  
Model Driven ◽  
Case System ◽  
Architectural Framework ◽  
Performance Check ◽  
High Level ◽  
Different Levels

Sensor-based digital systems for Instrumentation and Control (I&C) of nuclear reactors are quite complex in terms of architecture and functionalities. A high-level framework is highly required to pre-evaluate the system’s performance, check the consistency between different levels of abstraction and address the concerns of various stakeholders. In this work, we integrate the development process of I&C systems and the involvement of stakeholders within a model-driven methodology. The proposed approach introduces a new architectural framework that defines various concepts, allowing system implementations and encompassing different development phases, all actors, and system concerns. In addition, we define a new I&C Modeling Language (ICML) and a set of methodological rules needed to build different architectural framework views. To illustrate this methodology, we extend the specific use of an open-source system engineering tool, named Eclipse Papyrus, to carry out many automation and verification steps at different levels of abstraction. The architectural framework modeling capabilities will be validated using a realistic use case system for the protection of nuclear reactors. The proposed framework is able to reduce the overall system development cost by improving links between different specification tasks and providing a high abstraction level of system components.

scholarly journals Recent developments on the Stieltjes transform of generalized functions

1987 ◽  
Vol 10 (4) ◽  
pp. 641-670 ◽  
Author(s):  
Ram Sankar Pathak ◽  
Lokenath Debnath
Keyword(s):  
Final Section ◽  
Generalized Functions ◽  
Stieltjes Transform ◽  
Poisson Transform ◽  
Open Questions ◽  
The Laplace Transform ◽  
Recent Developments ◽  
The Subject ◽  
Abelian Theorems ◽  
Stieltjes Transforms

This paper is concerned with recent developments on the Stieltjes transform of generalized functions. Sections 1 and 2 give a very brief introduction to the subject and the Stieltjes transform of ordinary functions with an emphasis to the inversion theorems. The Stieltjes transform of generalized functions is described in section 3 with a special attention to the inversion theorems of this transform. Sections 4 and 5 deal with the adjoint and kernel methods used for the development of the Stieltjes transform of generalized functions. The real and complex inversion theorems are discussed in sections 6 and 7. The Poisson transform of generalized functions, the iteration of the Laplace transform and the iterated Stieltjes transfrom are included in sections 8, 9 and 10. The Stieltjes transforms of different orders and the fractional order integration and further generalizations of the Stieltjes transform are discussed in sections 11 and 12. Sections 13, 14 and 15 are devoted to Abelian theorems, initial-value and final-value results. Some applications of the Stieltjes transforms are discussed in section 16. The final section deals with some open questions and unsolved problems. Many important and recent references are listed at the end.

Moral und Hypermoral

2016 ◽  
Author(s):  
Arnold Gehlen
Keyword(s):  
Behavioral Science ◽  
Philosophical Anthropology ◽  
The State ◽  
Sociological Research ◽  
Levels Of Abstraction ◽  
The Enlightenment ◽  
Broad Scope ◽  
Magnum Opus ◽  
Different Levels ◽  
Evolutionary Interpretation

Moral and Hypermoral, Arnold Gehlen´s final book-length publication, is an elaboration on basic theses which had initially been brought forward in Gehlen´s anthropological magnum opus "Der Mensch". In this respect, this draft of a "pluralistic ethics" is conceived as an elaboration on as well as a concretion of his doctrine of man. In this book, Gehlen set himself the task of combining anthropology, behavioral science, and sociology in a “genealogy of morality”, thus exposing four interdependent forms of ethics: from an ethos of "reciprocity" via “eudaimonism” and “humanitarianism” to an ethos of institutions, including the state. Gehlen made a decisive stand against the "abstract ethics of the Enlightenment": systematically, his book is primarily an anthropological justification of ethics, conceived as a "majority of moral authorities" and "social regulations." These are not subjected to an evolutionary interpretation, that is, as progress from an ethics of proximity to a world-encompassing morality. Moralities, whether based on instinct or arising from the needs of particular institutions, are always culturally shaped and set on different levels of abstraction. With its broad scope, the book belongs in the context of basic philosophical-sociological research known as philosophical anthropology.

scholarly journals Examination of aerial diatom flushing across watersheds in Luxembourg, Oregon and Slovakia for tracing episodic hydrological connectivity

2015 ◽  
Vol 63 (3) ◽  
pp. 235-245 ◽  
Author(s):  
Laurent Pfister ◽  
Carlos E. Wetzel ◽  
Núria Martínez-Carreras ◽  
Jean François Iffly ◽  
Julian Klaus ◽  
...  
Keyword(s):  
Water Source ◽  
Interdisciplinary Studies ◽  
Transport Processes ◽  
Hydrological Connectivity ◽  
Freshwater Species ◽  
Rainfall Runoff ◽  
Holistic View ◽  
Preliminary Examination ◽  
Open Questions ◽  
Runoff Events

Abstract Hydrological processes research remains a field that is severely measurement limited. While conventional tracers (geochemicals, isotopes) have brought extremely valuable insights into water source and flowpaths, they nonetheless have limitations that clearly constrain their range of application. Integrating hydrology and ecology in catchment science has been repeatedly advocated as offering potential for interdisciplinary studies that are eventually to provide a holistic view of catchment functioning. In this context, aerial diatoms have been shown to have the potential for detecting of the onset/cessation of rapid water flowpaths within the hillslope-riparian zone-stream continuum. However, many open questions prevail as to aerial diatom reservoir size, depletion and recovery, as well as to their mobilisation and transport processes. Moreover, aerial diatoms remain poorly known compared to freshwater species and new species are still being discovered. Here, we ask whether aerial diatom flushing can be observed in three catchments with contrasting physiographic characteristics in Luxembourg, Oregon (USA) and Slovakia. This is a prerequisite for qualifying aerial diatoms as a robust indicator of the onset/cessation of rapid water flowpaths across a wider range of physiographical contexts. One species in particular, (Hantzschia amphioxys (Ehr.) Grunow), was found to be common to the three investigated catchments. Aerial diatom species were flushed, in different relative proportions, to the river network during rainfall-runoff events in all three catchments. Our take-away message from this preliminary examination is that aerial diatoms appear to have a potential for tracing episodic hydrological connectivity through a wider range of physiographic contexts and therefore serve as a complementary tool to conventional hydrological tracers.

scholarly journals The Parietal Cortex in Sensemaking: The Dissociation of Multiple Types of Spatial Information

2013 ◽  
Vol 2013 ◽  
pp. 1-14 ◽  
Author(s):  
Yanlong Sun ◽  
Hongbin Wang
Keyword(s):  
Parietal Cortex ◽  
Spatial Information ◽  
Mathematical Thinking ◽  
Hierarchical Organization ◽  
Levels Of Abstraction ◽  
Perceptual Analysis ◽  
Different Types ◽  
Sensemaking Process ◽  
Network Simulations ◽  
Different Levels

According to the data-frame theory, sensemaking is a macrocognitive process in which people try to make sense of or explain their observations by processing a number of explanatory structures called frames until the observations and frames become congruent. During the sensemaking process, the parietal cortex has been implicated in various cognitive tasks for the functions related to spatial and temporal information processing, mathematical thinking, and spatial attention. In particular, the parietal cortex plays important roles by extracting multiple representations of magnitudes at the early stages of perceptual analysis. By a series of neural network simulations, we demonstrate that the dissociation of different types of spatial information can start early with a rather similar structure (i.e., sensitivity on a common metric), but accurate representations require specific goal-directed top-down controls due to the interference in selective attention. Our results suggest that the roles of the parietal cortex rely on the hierarchical organization of multiple spatial representations and their interactions. The dissociation and interference between different types of spatial information are essentially the result of the competition at different levels of abstraction.

A Comparison of Mothers' Individual and Simultaneous Book Sharing With Preschool Siblings

2002 ◽  
Vol 11 (2) ◽  
pp. 175-189 ◽  
Author(s):  
Anne van Kleeck ◽  
Amy Beckley-McCall
Keyword(s):  
Mixed Strategy ◽  
Developmental Differences ◽  
Older Children ◽  
Levels Of Abstraction ◽  
Linguistic Complexity ◽  
Reading Condition ◽  
Book Sharing ◽  
Simultaneous Reading ◽  
Fine Tune ◽  
Different Levels

Many studies have demonstrated that adults fine tune book-sharing discussions to the developmental levels of preschoolers, but little is known regarding how reading simultaneously to different-aged preschoolers is negotiated. We observed five mothers of different-aged preschoolers sharing books with each child individually and with both children together. Analyses focused on the linguistic complexity of the book, the amount of time spent sharing a book, and on several aspects of the mothers' book-sharing mediation. Results revealed developmental differences on several measures of how mothers mediated with younger as compared to older children individually. Book complexity, the time spent sharing books, and the percent of utterances at higher levels of abstraction were higher when reading to the older children; the number of mediation strategies per minute and the percent of mothers' behaviors that were used to get and maintain attention were higher when reading to the younger children. When reading to both children simultaneously, which aspects of the mediation fell at these different levels varied among the different mothers. This suggests that different mothers reach different solutions to the task of simultaneously reading to preschoolers of different ages. One mother approached the simultaneous book sharing much as she did sharing a book with her older child, one mother approached it as she did with her younger child, one mother simply read and did little mediation, and two mothers appeared to use a mixed strategy in the simultaneous reading condition.

scholarly journals Priming and substrate quality interactions in soil organic matter models

2013 ◽  
Vol 10 (3) ◽  
pp. 2089-2103 ◽  
Author(s):  
T. Wutzler ◽  
M. Reichstein
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Balance Model ◽  
Levels Of Abstraction ◽  
Substrate Quality ◽  
Substrate Limitation ◽  
Energy Limitation ◽  
Bare Fallow ◽  
Different Levels

Abstract. Interactions between different qualities of soil organic matter (SOM) affecting their turnover are rarely represented in models. In this study, we propose three mathematical strategies at different levels of abstraction to represent those interactions. By implementing these strategies into the Introductory Carbon Balance Model (ICBM) and applying them to several scenarios of litter input, we show that the different levels of abstraction are applicable at different timescales. We present a simple one-parameter equation of substrate limitation that can straightforwardly be implemented into other models of SOM dynamics at decadal timescale. The study demonstrates how substrate quality interactions can explain patterns of priming effects, accelerate turnover in FACE experiments, and the slowdown of decomposition in long-term bare fallow experiments as an effect of energy limitation of microbial biomass. The mechanisms of those interactions need to be further scrutinized empirically for a more complete understanding. Overall, substrate quality interactions contribute to both understanding and quantitatively modelling SOM dynamics.

Sign in / Sign up

Export Citation Format

Share Document