DESICCATION–REHYDRATION STRESS REVEALED BY SUGAR-METABOLITE-RESERVE MODEL

2021 ◽  
pp. 1-19
Author(s):  
JULIANA M. BERBERT ◽  
KAREN A. OLIVEIRA ◽  
RAFAELA F. MARTIN ◽  
DANILO C. CENTENO
Keyword(s):  
Water Supply ◽  
Climate Changes ◽  
Compartmental Model ◽  
Numerical Solutions ◽  
Mathematical Formulation ◽  
Photosynthetic Organisms ◽  
Crop Field ◽  
Long Time ◽  
External Conditions ◽  
New Perspective

We focus on the evaluation of photosynthetic organisms. Some species and tissues can endure periods of the dry season because they rely on a robust dynamics of metabolites. The metabolic dynamics are complex and challenging to address because it involves several steps, usually with hundreds of metabolites. The metabolites densities vary among species and tissues and respond to external conditions, such as an environmental stimulus like water supply. Understanding these responses, particularly the desiccation–rehydration processes, are important both economically and evolutionarily, especially in the presence of climate change. Therefore, we propose a new way to analyze the dynamics of metabolites with a compartmental model which explores the metabolites densities’ dependence on water explicitly. We use a mathematical formulation to model the dynamics among three essential metabolites classes: sugar ([Formula: see text]), active metabolite ([Formula: see text]), and reserve accumulation ([Formula: see text]). Through stability analysis and numerical solutions, we characterize regions on the phase space, defined by the transition rates between the classes [Formula: see text] to [Formula: see text] and [Formula: see text] to [Formula: see text], where the system diverges or approaches zero. We show that different species and tissues respond distinctly to desiccation processes, being more or less resilient according to the transitions rate between the compartments of the model. Furthermore, the effects of water supply fluctuation, due to the desiccation–rehydration processes, show that unless the organism has a robust reservoir metabolism, the system cannot support itself for a long time. Many results corroborate experimental observations, and others provide a new perspective on the studies of metabolic dynamics, such as the significance of the reservoir metabolism. We understand that knowing the organism’s response to abiotic changes, particularly that of the water supply, may improve our management of the use of these organisms, for example, in the crop field during climate changes.

Psychology: Volume 5

2019 ◽  
Keyword(s):  
World View ◽  
Science Volume ◽  
Western World ◽  
Mental Life ◽  
Long Time ◽  
The Difference ◽  
New Perspective ◽  
Indian Setting ◽  
The Mind ◽  
The Relationship

This survey of research on psychology in five volumes is a part of a series undertaken by the ICSSR since 1969, which covers various disciplines under social science. Volume Five of this survey, Explorations into Psyche and Psychology: Some Emerging Perspectives, examines the future of psychology in India. For a very long time, intellectual investments in understanding mental life have led to varied formulations about mind and its functions across the word. However, a critical reflection of the state of the disciplinary affairs indicates the dominance of Euro-American theories and methods, which offer an understanding coloured by a Western world view, which fails to do justice with many non-Western cultural settings. The chapters in this volume expand the scope of psychology to encompass indigenous knowledge available in the Indian tradition and invite engaging with emancipatory concerns as well as broadening the disciplinary base. The contributors situate the difference between the Eastern and Western conceptions of the mind in the practice of psychology. They look at this discipline as shaped by and shaping between systems like yoga. They also analyse animal behaviour through the lens of psychology and bring out insights about evolution of individual and social behaviour. This volume offers critique the contemporary psychological practices in India and offers a new perspective called ‘public psychology’ to construe and analyse the relationship between psychologists and their objects of study. Finally, some paradigmatic, pedagogical, and substantive issues are highlighted to restructure the practice of psychology in the Indian setting.

Securing 2020 vision for 2030: climate change and ensuring resilience in water and sanitation services

2010 ◽  
Vol 1 (1) ◽  
pp. 2-16 ◽  
Author(s):  
Guy Howard ◽  
Katrina Charles ◽  
Kathy Pond ◽  
Anca Brookshaw ◽  
Rifat Hossain ◽  
...  
Keyword(s):  
Climate Change ◽  
Drinking Water ◽  
Water Supply ◽  
Climate Changes ◽  
Water And Sanitation ◽  
Sanitation Services ◽  
Development Goals ◽  
Management Approaches ◽  
Sanitation Systems ◽  
Water Supply And Sanitation

Drinking-water supply and sanitation services are essential for human health, but their technologies and management systems are potentially vulnerable to climate change. An assessment was made of the resilience of water supply and sanitation systems against forecast climate changes by 2020 and 2030. The results showed very few technologies are resilient to climate change and the sustainability of the current progress towards the Millennium Development Goals (MDGs) may be significantly undermined. Management approaches are more important than technology in building resilience for water supply, but the reverse is true for sanitation. Whilst climate change represents a significant threat to sustainable drinking-water and sanitation services, through no-regrets actions and using opportunities to increase service quality, climate change may be a driver for improvements that have been insufficiently delivered to date.

scholarly journals Borehole Rehabilitation: A Case Study in the Dunkwa Mining Town

2020 ◽  
Vol 20 (2) ◽  
pp. 11-17
Author(s):  
A. Ewusi ◽  
J. Seidu
Keyword(s):  
Water Supply ◽  
Central Region ◽  
Pumping Test ◽  
Implementation Cost ◽  
Mining Town ◽  
Long Time ◽  
Borehole Camera ◽  
The Cost ◽  
Very High

Rehabilitation works were carried out on boreholes in the Dunkwa Mining town in the Central Region of Ghana. These works were carried out because the boreholes had lost their original yields due to clogging, corrosion and encrustation and had been abandoned for a long time. The cost of drilling a new well and assessing the productivity of the well is $4,500 which is more expensive that carrying out rehabilitation works which is cheaper, about $800. Also, the initial yields of the boreholes were very high according to the feasibility report which is not a common characteristic of the rocks in the area. Camera inspection followed by rehabilitation, pre and post pumping tests were carried out to assess whether there has been an improvement in their yield after the exercise and that the yield obtained will be adequate for a water supply design. Results show that all the boreholes had an improvement in their yields (57.19 - 259.80 %) after the rehabilitation. It can therefore be concluded that rehabilitation is effective in restoring boreholes to their original yields. Organisations drilling boreholes to communities can take advantage of rehabilitation of the existing boreholes located in the communities which are high yielding, thereby reducing project implementation cost. Keywords: Borehole Rehabilitation, Borehole Yields, Borehole Camera Inspection, Pumping Test

scholarly journals Long-time behavior of numerical solutions to nonlinear fractional ODEs

2020 ◽  
Vol 54 (1) ◽  
pp. 335-358 ◽  
Author(s):  
Dongling Wang ◽  
Aiguo Xiao ◽  
Jun Zou
Keyword(s):  
Numerical Methods ◽  
Numerical Solutions ◽  
Analytical Techniques ◽  
Decay Rates ◽  
Leibniz Rule ◽  
Discrete Version ◽  
Time Behavior ◽  
Long Time Behavior ◽  
Integration Schemes ◽  
Long Time

In this work, we study the long time behavior, including asymptotic contractivity and dissipativity, of the solutions to several numerical methods for fractional ordinary differential equations (F-ODEs). The existing algebraic contractivity and dissipativity rates of the solutions to the scalar F-ODEs are first improved. In order to study the long time behavior of numerical solutions to fractional backward differential formulas (F-BDFs), two crucial analytical techniques are developed, with the first one for the discrete version of the fractional generalization of the traditional Leibniz rule, and the other for the algebraic decay rate of the solution to a linear Volterra difference equation. By means of these auxiliary tools and some natural conditions, the solutions to F-BDFs are shown to be contractive and dissipative, and also preserve the exact contractivity rate of the continuous solutions. Two typical F-BDFs, based on the Grünwald–Letnikov formula and L1 method respectively, are studied. For high order F-BDFs, including convolution quadrature schemes based on classical second order BDF and product integration schemes based on quadratic interpolation approximation, their numerical contractivity and dissipativity are also developed under some slightly stronger conditions. Numerical experiments are presented to validate the long time qualitative characteristics of the solutions to F-BDFs, revealing very different decay rates of the numerical solutions in terms of the the initial values between F-ODEs and integer ODEs and demonstrating the superiority of the structure-preserving numerical methods.

Motion of an array of drops through a cylindrical tube

1998 ◽  
Vol 358 ◽  
pp. 1-28 ◽  
Author(s):  
C. COULLIETTE ◽  
C. POZRIKIDIS
Keyword(s):  
Stokes Flow ◽  
Apparent Viscosity ◽  
Numerical Solutions ◽  
Initial Period ◽  
Mathematical Formulation ◽  
Axisymmetric Flow ◽  
Circular Cross Section ◽  
Cylindrical Tube ◽  
Boundary Integral ◽  
Tube Radius

We study the pressure-driven transient motion of a periodic file of deformable liquid drops through a cylindrical tube with circular cross-section, at vanishing Reynolds number. The investigations are based on numerical solutions of the equations of Stokes flow obtained by the boundary-integral method. It is assumed that the viscosity and density of the drops are equal to those of the suspending fluid, and the interfaces have constant tension. The mathematical formulation uses the periodic Green's function of the equations of Stokes flow in a domain that is bounded externally by a cylindrical tube, which is computed by tabulation and interpolation. The surface of each drop is discretized into quadratic triangular elements that form an unstructured interfacial grid, and the tangential velocity of the grid-points is adjusted so that the mesh remains regular for an extended but limited period of time. The results illustrate the nature of drop motion and deformation, and thereby extend previous studies for axisymmetric flow and small-drop small-deformation theories. It is found that when the capillary number is sufficiently small, the drops start deforming from a spherical shape, and then reach slowly evolving quasi-steady shapes. In all cases, the drops migrate radially toward the centreline after an initial period of rapid deformation. The apparent viscosity of the periodic suspension is expressed in terms of the effective pressure gradient necessary to drive the flow at constant flow rate. For a fixed period of separation, the apparent viscosity of a non-axisymmetric file is found to be higher than that of an axisymmetric file. In the case of non-axisymmetric motion, the apparent viscosity reaches a minimum at a certain ratio of the drop separation to tube radius. Drops with large effective radii to tube radius ratios develop slipper shapes, similar to those assumed by red blood cells in flow through capillaries, but only for capillary numbers in excess of a critical value.

scholarly journals Acoustic modes in jet and wake stability

2019 ◽  
Vol 867 ◽  
pp. 804-834 ◽  
Author(s):  
Eduardo Martini ◽  
André V. G. Cavalieri ◽  
Peter Jordan
Keyword(s):  
Dispersion Relation ◽  
Acoustic Waves ◽  
Reverse Flow ◽  
Saddle Points ◽  
Vortex Sheet ◽  
Necessary Condition ◽  
Absolute Instability ◽  
Acoustic Modes ◽  
Long Time ◽  
New Perspective

Motivated by recent studies that have revealed the existence of trapped acoustic waves in subsonic jets (Towne et al., J. Fluid Mech., vol. 825, 2017, pp. 1113–1152), we undertake a more general exploration of the physics associated with acoustic modes in jets and wakes, using a double vortex-sheet model. These acoustic modes are associated with eigenvalues of the vortex-sheet dispersion relation; they are discrete modes, guided by the vortex sheet; they may be either propagative or evanescent; and under certain conditions they behave in the manner of acoustic-duct modes. By analysing these modes we show how jets and wakes may both behave as waveguides under certain conditions, emulating ducts with soft or hard walls, with the vortex-sheet impedance providing effective ‘wall’ conditions. We consider, in particular, the role that upstream-travelling acoustic modes play in the dispersion-relation saddle points that underpin the onset of absolute instability. The analysis illustrates how departure from duct-like behaviour is a necessary condition for absolute instability, and this provides a new perspective on the stabilising and destabilising effects of reverse flow, temperature ratio and compressibility; it also clarifies the differing symmetries of jet (symmetric) and wake (antisymmetric) instabilities. An energy balance, based on the vortex-sheet impedance, is used to determine stability conditions for the acoustic modes: these may become unstable in supersonic flow due to an energy influx through the shear layers. Finally, we construct the impulse response of flows with zero and finite shear-layer thickness. This allows us to show how the long-time wavepacket behaviour is indeed determined by interaction between Kelvin–Helmholtz and acoustic modes.

Modeling long-time behaviors of industrial multiphase reactors for CO2 capture using CFD-based compartmental model

2020 ◽  
Vol 395 ◽  
pp. 125034
Author(s):  
Minjun Kim ◽  
Seongeon Park ◽  
Dongwoo Lee ◽  
Soogil Lim ◽  
Minho Park ◽  
...  
Keyword(s):  
Co2 Capture ◽  
Compartmental Model ◽  
Multiphase Reactors ◽  
Long Time

Numerical Method with the Third-Order ENO Reconstruction Satisfying Two Conversation Laws for Linear Advection Equation

2011 ◽  
Vol 130-134 ◽  
pp. 2969-2972
Author(s):  
Rong San Chen ◽  
An Ping Liu
Keyword(s):  
Numerical Solutions ◽  
Advection Equation ◽  
Finite Volume Schemes ◽  
Third Order ◽  
The Third ◽  
Linear Advection Equation ◽  
Long Time ◽  
Super Convergence ◽  
Better Than ◽  
Eno Scheme

In recent years, Mao and his co-workers developed a class of finite-volume schemes for evolution partial differential equations, see [1-5].The schemes show a super-convergence quality and have good structure-preserving property in long-time numerical simulations. In [6], Chen and Ma developed a scheme which combine the idea of paper [5] and that of the the second-order ENO scheme [7]. In this paper, we propose a scheme which extend the result of [6] and obtain the scheme using the third-order ENO reconstruction. Numerical experiments show that our scheme is robust in long-time behaviors. Numerical solutions are far better than those of [6].

ECOLOGICAL MODELING OF TALITROIDES TOPITOTUM (CRUSTACEA: AMPHIPODA)

2014 ◽  
Vol 22 (04) ◽  
pp. 601-616 ◽  
Author(s):  
ERNESTO AUGUSTO BUENO DA FONSECA LIMA ◽  
CRISTANE MATAVELLI ◽  
CLÁUDIA PIO FERREIRA ◽  
WESLEY AUGUSTO CONDE GODOY
Keyword(s):  
Reproductive Strategies ◽  
Climate Changes ◽  
Compartmental Model ◽  
Global Climate ◽  
Biological Information ◽  
Model Parameters ◽  
Potential Influence ◽  
Global Climate Changes ◽  
Temporal Course ◽  
Pattern Development

A compartmental model was developed to describe the temporal course of an exotic amphipod's population, Talitroides topitotum, in an Atlantic Forest habitat in Brazil. Extensive biological information — including breeding pattern, development and mortality rates, and temperature dependence of the parameters — were considered in the model. A genetic algorithm was used to estimate model parameters by comparing simulation results with field data. This allowed us to discuss the reproductive strategies adopted by this species and to analyze the potential influence of global climate changes on its populations dynamics.

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