Thermodynamic optimality principles in Earth sciences

2021 ◽  
Author(s):  
Stanislaus J. Schymanski ◽  
Benjamin Dewals ◽  
Henk A. Dijkstra ◽  
Hisashi Ozawa ◽  
Erwin Zehe
Keyword(s):  
State Variables ◽  
Atmospheric Conditions ◽  
Short Term ◽  
Initial State ◽  
Rigorous Testing ◽  
Common Framework ◽  
Flow Through ◽  
Optimality Principles ◽  
Systematic Framework

<p>Ecohydrological systems are a result of long-term co-evolution of soils, biota and atmospheric conditions, and often respond to perturbations in non-intuitive ways. Their short-term responses can be explained and sometimes predicted if we understand the underlying dynamic processes and if we can observe the initial state precisely enough. However, how do they co-evolve in the long-term after a change in the boundary conditions? In 1922, Alfred Lotka hypothesised that the natural selection governing the evolution of biota and composition of ecosystems may be obeying some thermodynamic principles related to maximising energy flow through these systems. Similar thoughts have been formulated for various components of the Earth system and individual processes, such as heat transport in the atmosphere and oceans, erosion and sediment transport in river systems and estuaries, the formation of vegetation patterns, and many others. Different thermodynamic optimality principles have been applied to predict or explain a given system property or behaviour, of which the maximum entropy production and the maximum power principles are most widespread. However, the different studies did not use a common systematic approach for the formulation of the relevant system boundaries, state variables and exchange fluxes, resulting in considerable ambiguity about the application of thermodynamic optimality principles in the scientific community. Such a systematic framework has been developed recently and can be tested online at:</p><p><span><span>https://renkulab.io/projects/stanislaus.schymanski/thermodynamic_optimality_blueprint</span></span></p><p>In the present study, we illustrate how such a common framework can be used to classify and compare different applications of thermodynamic optimality principles in the literature, and discuss the insights gained and key criteria for a more rigorous testing of such principles.</p>

scholarly journals Perception and risk of Covid-19 and climate change: investigating analogies in a common framework

2020 ◽  
Vol 3 ◽  
Author(s):  
Antonello Pasini ◽  
Fulvio Mazzocchi
Keyword(s):  
Climate Change ◽  
Structural Changes ◽  
Short Term ◽  
Common Features ◽  
Risk Equation ◽  
Related Risk ◽  
Policy Level ◽  
Common Framework

This paper investigates analogies in the dynamics of Covid-19 pandemic and climate change. A comparison of their common features (such as nonlinearity and inertia) and differences helps us to achieve a correct scientific perception of both situations, increasing the chances of actions for their solutions. Besides, applying to both the risk equation provides different angles to analyse them, something that may result useful especially at the policy level. It shows that not only short-term interventions are needed, but also long-term strategies involving some structural changes. More specifically, it also shows that, even if climate change is probably more critical and long-lasting than the Covid-19 crisis, we still have, at least currently, more options for reducing its related risk.

Left-Right Orientations and Voting Behavior

2017 ◽  
Author(s):  
Willy Jou ◽  
Russell J. Dalton
Keyword(s):  
Political Parties ◽  
Voting Behavior ◽  
Policy Preferences ◽  
Short Term ◽  
Conservative Policy ◽  
Common Framework ◽  
Societal Influences ◽  
Voting Choice

One of the ways that citizens and elites orient themselves to politics is in reference to a Left-Right vocabulary. Left and Right, respectively, refer to a specific set of progressive and conservative policy preferences and political goals. Thus, Left-Right becomes a framework for positioning oneself, political figures, and political parties into a common framework. Most citizens identify themselves in Left-Right terms and their distribution of these orientations vary across nations. These orientations arise both from long-term societal influences and from the short-term issues of the day. Most people also place political parties in Left-Right terms. This leads citizens to use Left-Right comparisons as an important factor in their voting choice, although this impact varies considerably across nations. Most parties attract voters that broadly share their Left-Right orientations.

scholarly journals Long-term effects of the antibacterial agent triclosan on marine periphyton communities

2014 ◽  
Author(s):  
Martin Eriksson ◽  
Henrik Johansson ◽  
Viktor Fihlman ◽  
Alexander Grehn ◽  
Kemal Sanli ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Antibacterial Agent ◽  
Control Level ◽  
Pulse Amplitude ◽  
Long Term Effects ◽  
Carbon Utilization ◽  
Short Term ◽  
Flow Through ◽  
Community Tolerance

Triclosan (TCS) is a widely used antibacterial agent that has become a ubiquitous contaminant in freshwater, estuary and marine environments. Concerns for potential adverse effects of TCS have been described in several recent risk assessments. Effects on freshwater microbial communities have been quite well studied but studies addressing effects on marine microbial communities are scarce. Here we describe short- and long-term effects of TCS on marine periphyton (microbial biofilm) communities. Short-term effects on photosynthesis were estimated after 60 – 210 minutes exposure. Long-term effects on photosynthesis, chlorophyll fluorescence, pigment content, community tolerance and bacterial carbon utilization were studied after exposing periphyton for 17 days in flow-through microcosms to 0.316 - 10 000 nM TCS. Results from the short-term studies show that TCS is toxic to periphyton photosynthesis. EC50 values of 1080 and 3000 nM were estimated using 14CO2-incorporation and Pulse Amplitude Modulation (PAM), respectively. After long-term TCS exposure in flow-through microcosms photosynthesis estimated using PAM was, however, not inhibited by TCS concentrations up to 1000 nM, but instead increased with increasing TCS concentration. Similarly, the amount of photosynthetic pigments increased after an exposure of 31.6 nM TCS and higher; at 316 nM TCS the pigment amounts reached between 140 and 190% of the control level. Pollution-Induced Community Tolerance (PICT) was observed for algae and cyanobacteria at 100 nM TCS and higher. In spite of the widespread use of TCS as an antibacterial agent, the compound did not have any effects on bacterial carbon utilization after long-term exposure.

scholarly journals Long-Term versus Short-Term Contingencies in Asset Allocation

2017 ◽  
Vol 52 (5) ◽  
pp. 2277-2303
Author(s):  
Mahmoud Botshekan ◽  
André Lucas
Keyword(s):  
Asset Pricing ◽  
Stock Market ◽  
Asset Allocation ◽  
Yield Spread ◽  
State Variables ◽  
Dividend Yield ◽  
Short Term ◽  
Out Of Sample ◽  
Sharpe Ratios

We investigate whether long-term and short-term components of typical conditioning variables in asset pricing studies, such as the dividend yield or yield spread, have different implications for optimal asset allocation. We argue that short-term components relate mostly to momentum, and long-term components relate mostly to mean-reversion effects, respectively. Therefore, they may have a different information content for investors with different horizons. We obtain improvements in terms of out-of-sample Sharpe ratios and expected utilities for decomposed state variables that directly reflect information related to the stock market, such as the dividend yield and stock market trend.

scholarly journals Long-term effects of the antibacterial agent triclosan on marine periphyton communities

2014 ◽  
Author(s):  
Martin Eriksson ◽  
Henrik Johansson ◽  
Viktor Fihlman ◽  
Alexander Grehn ◽  
Kemal Sanli ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Antibacterial Agent ◽  
Control Level ◽  
Pulse Amplitude ◽  
Long Term Effects ◽  
Carbon Utilization ◽  
Short Term ◽  
Flow Through ◽  
Community Tolerance

Triclosan (TCS) is a widely used antibacterial agent that has become a ubiquitous contaminant in freshwater, estuary and marine environments. Concerns for potential adverse effects of TCS have been described in several recent risk assessments. Effects on freshwater microbial communities have been quite well studied but studies addressing effects on marine microbial communities are scarce. Here we describe short- and long-term effects of TCS on marine periphyton (microbial biofilm) communities. Short-term effects on photosynthesis were estimated after 60 – 210 minutes exposure. Long-term effects on photosynthesis, chlorophyll fluorescence, pigment content, community tolerance and bacterial carbon utilization were studied after exposing periphyton for 17 days in flow-through microcosms to 0.316 - 10 000 nM TCS. Results from the short-term studies show that TCS is toxic to periphyton photosynthesis. EC50 values of 1080 and 3000 nM were estimated using 14CO2-incorporation and Pulse Amplitude Modulation (PAM), respectively. After long-term TCS exposure in flow-through microcosms photosynthesis estimated using PAM was, however, not inhibited by TCS concentrations up to 1000 nM, but instead increased with increasing TCS concentration. Similarly, the amount of photosynthetic pigments increased after an exposure of 31.6 nM TCS and higher; at 316 nM TCS the pigment amounts reached between 140 and 190% of the control level. Pollution-Induced Community Tolerance (PICT) was observed for algae and cyanobacteria at 100 nM TCS and higher. In spite of the widespread use of TCS as an antibacterial agent, the compound did not have any effects on bacterial carbon utilization after long-term exposure.

Nutrient economics and trophic status of Lakes Sorell and Crescent, Tasmania

1976 ◽  
Vol 27 (1) ◽  
pp. 151
Author(s):  
DMH Cheng ◽  
PA Tyler
Keyword(s):  
Trophic Status ◽  
Nutrient Inputs ◽  
Short Term ◽  
Management Plans ◽  
Increase Productivity ◽  
Flow Through ◽  
Polymictic Lakes ◽  
Enriched Cultures

Effects of various nutrients on short-term photosynthetic carbon uptake and longer-term yield of algae were assayed for two similar, connected lakes (Lake Sorell flowing into Lake Crescent) with contrasting plankton populations. Phosphorus (P) and phosphorus plus nitrogen (P+N) were the only nutrients to stimulate 14C uptake, and more for Lake Crescent than for Lake Sorell, over 3-h incubations, and P+N was only marginally more effective than P alone. Added SiO2 was inhibitory in short-term but not in long-term incubations. During 3-day incubations, P, N and P+N increased 14C uptake for Lake Sorell but usually not for Lake Crescent. Micronutrients and chelators also accelerated 14C incorporation for Lake Sorell but not for Lake Crescent. No nutrient tested singly increased the ultimate yield of algae, but P+N, Na2CO3 and SiO2 added incrementally produced marked, incremental increases in yield, and more so in Lake Sorell than in Lake Crescent. Addition of micronutrients had no further stimulatory effect. Removal of tripton from lake samples seriously impaired yields, even in P+N-enriched cultures. Incremental replacement of tripton produced incremental restoration of yields. Volume for volume, Lake Crescent water contained more tripton and a more organic tripton than Lake Sorell water. Weight for weight, Lake Crescent tripton stimulated faster growth than Lake Sorell tripton but ultimate yields were the same. Micronutrients and chelators together could substitute for native tripton, the role of which seems to be the maintenance of micronutrients in solution in the oxidizing milieu of the polymictic lakes. The greater productivity and greater phytoplankton biomass of Lake Crescent rests on its greater tripton load, derived from greater scouring of sediments, its flow through from Lake Sorell and an abundant fringing marshland. It is likely that the distinctive floras of the two lakes are adapted to the different nutrient conditions, so that flow-through inocula of Lake Sorell algae cannot become established in Lake Crescent. As Lakes Sorell and Crescent are already mesotrophic and eutrophic respectively, and since additions of P and P+N considerably increase productivity and yield, management plans for this recreational area should seek to limit nutrient inputs.

scholarly journals Kinocardiography Derived from Ballistocardiography and Seismocardiography Shows High Repeatability in Healthy Subjects

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 815
Author(s):  
Amin Hossein ◽  
Jérémy Rabineau ◽  
Damien Gorlier ◽  
Jose Ignacio Juarez Del Rio ◽  
Philippe van de Borne ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Myocardial Contraction ◽  
Body Motion ◽  
Short Term ◽  
Left Lateral Decubitus Position ◽  
Cardiac Condition ◽  
Flow Through ◽  
The Difference ◽  
High Repeatability

Recent years have witnessed an upsurge in the usage of ballistocardiography (BCG) and seismocardiography (SCG) to record myocardial function both in normal and pathological populations. Kinocardiography (KCG) combines these techniques by measuring 12 degrees-of-freedom of body motion produced by myocardial contraction and blood flow through the cardiac chambers and major vessels. The integral of kinetic energy (iK) obtained from the linear and rotational SCG/BCG signals, and automatically computed over the cardiac cycle, is used as a marker of cardiac mechanical function. The present work systematically evaluated the test–retest (TRT) reliability of KCG iK derived from BCG/SCG signals in the short term (<15 min) and long term (3–6 h) on 60 healthy volunteers. Additionally, we investigated the difference of repeatability with different body positions. First, we found high short-term TRT reliability for KCG metrics derived from SCG and BCG recordings. Exceptions to this finding were limited to metrics computed in left lateral decubitus position where the TRT reliability was moderate-to-high. Second, we found low-to-moderate long-term TRT reliability for KCG metrics as expected and confirmed by blood pressure measurements. In summary, KCG parameters derived from BCG/SCG signals show high repeatability and should be further investigated to confirm their use for cardiac condition longitudinal monitoring.

Validity of an Ecotoxicological Test System: Short-Term and Long-Term Effects of Arsenate on Marine Periphyton Communities in Laboratory Systems

1988 ◽  
Vol 45 (10) ◽  
pp. 1807-1815 ◽  
Author(s):  
Hans Blanck ◽  
Sten-Åke Wängberg
Keyword(s):  
Relevant Information ◽  
Test System ◽  
Physiological Parameter ◽  
Long Term Effects ◽  
Short Term ◽  
Ecotoxicological Test ◽  
Arsenate Stress ◽  
Flow Through ◽  
Chlorophyll A Content

Periphyton communities were established on glass substratum in the Gullmar Fjord (Sweden) and their sensitivity to arsenate was determined with short-term photosynthesis experiments. The study was done in May 1984 when phosphate levels were low. A 1-h exposure to arsenate gave IC20 (concentration required to inhibit photosynthesis by 20%) values of 0.4 μM. Communities established indoors in a flow-through aquaria system were substantially different from the fjord communities in terms of structure and biomass, although photosynthesis showed a similar sensitivity (IC20 = 0.6 μM). To explore the validity of this short-term ecotoxicological test system, we used a set of indoor, flow-through aquaria to study long-term effects (3 wk) on communities established under arsenate stress. Arsenate was added continuously at 0.1–10 μM above background levels (7 nM). Species composition as well as carbon, nitrogen, and chlorophyll a content of the communities were affected at 0.2–0.8 μM (IC20). This is in good agreement with the sensitivity of the short-term test. We conclude that inhibition of the physiological parameter photosynthesis is relevant information for the understanding of ecological events caused by arsenate stress in the periphyton communities. At least for effects of arsenate, the short-term metabolic test system can be used for valid predictions of gross changes in periphyton community structure and production. Comparison with arsenic levels in polluted coastal areas of Sweden lead to the conclusion that periphyton communities may be affected, particularly when phosphorus levels are low.

Conceptual short-term memory (CSTM) supports core claims of Christiansen and Chater

2016 ◽  
Vol 39 ◽  
Author(s):  
Mary C. Potter
Keyword(s):  
Working Memory ◽  
Rapid Serial Visual Presentation ◽  
Language Comprehension ◽  
Short Term Memory ◽  
Visual Presentation ◽  
Long Term Memory ◽  
Short Term ◽  
Term Memory ◽  
Use Of Knowledge

AbstractRapid serial visual presentation (RSVP) of words or pictured scenes provides evidence for a large-capacity conceptual short-term memory (CSTM) that momentarily provides rich associated material from long-term memory, permitting rapid chunking (Potter 1993; 2009; 2012). In perception of scenes as well as language comprehension, we make use of knowledge that briefly exceeds the supposed limits of working memory.

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