A social-ecological analysis of ecosystem services supply and trade-offs in European wood-pastures

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Hartel, Tibor

2018-01-01

Wood-pastures are complex social-ecological systems (SES), which are the product of long-term interaction between society and its surrounding landscape. Traditionally characterized by multifunctional low-intensity management that enhanced a wide range of ecosystem services (ES), current farm management has shifted toward more intensive farm models. This study assesses the supply of ES in four study areas dominated by managed wood-pastures in Spain, Sweden, and Romania. On the basis of 144 farm surveys and the use of multivariate techniques, we characterize farm management and structure in the study areas and identify the trade-offs in ES supply associated with this management. We link these trade-offs to multiple factors that characterize the landholding: economic, social, environmental, technological, and governance. Finally, we analyze how landholders’ values and perspectives have an effect on management decisions. Results show a differentiated pattern of ES supply in the four study areas. We identified four types of trade-offs in ES supply that appear depending on what is being promoted by the farm management and that are associated with different dimensions of wood-pasture management: productivity-related trade-offs, crop production–related trade-offs, multifunctionality-related trade-offs, and farm accessibility–related trade-offs. These trade-offs are influenced by complex interactions between the properties of the SES, which have a direct influence on landholders’ perspectives and motivations. The findings of this paper advance the understanding of the dynamics between agroecosystems and society and can inform system-based agricultural and conservation policies. PMID:29732404

Trade-off analysis of ecosystem services in Eastern Europe

NARCIS (Netherlands)

Ruijs, A.; Wossink, Ada; Kortelainen, M.; Alkemade, R.; Schulp, C.J.E.

2013-01-01

In this paper we assess trade-offs between ecosystem services in a spatially explicit manner. From a supply side perspective, we estimate opportunity costs, which reflect in monetary terms the trade-offs between ecosystem services due to a marginal land use change. These are based on estimation of

Time-Space Trade-Offs

DEFF Research Database (Denmark)

Pagter, Jakob Illeborg

. The area of time-space trade-offs deals with both upper and lower bounds and both are interesting, theoretically as well as practically. The viewpoint of this dissertation is theoretical, but we believe that some of our results can find applications in practice as well. The last four years has witnessed...... perspective hierarchical memory layout models are the most interesting. Such models are called external memory models, in contrast to the internal memory models discussed above. Despite the fact that space might be of great relevance when solving practical problems on real computers, no theoretical model...... capturing space (and time simultaneously) has been defined. We introduce such a model and use it to prove so-called IOspace trade-offs for Sorting. Building on the abovementioned techniques for time-space efficient internal memory Sorting, we develop the first IO-space efficient external memory Sorting...

Competing values, tensions and trade-offs in management of nuclear power plants.

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Reiman, Teemu; Rollenhagen, Carl

2012-01-01

The specific goal of the study is to look how tensions, competing values and trade-offs manifest in the management of nuclear power plants. Second goal is to inspect how existing frameworks, such as Competing Values Framework, can be used to model the tensions. Empirical data consists of thirty interviews that were conducted as part of a NKS study on safety culture in the Nordic nuclear branch. Eight trade-offs are identified based on a grounded theory based analysis of the interview data. The competing values and potential tensions involved in the trade-offs are discussed.

Dynamic modeling of the tradeoff between productivity and safety in critical engineering systems

International Nuclear Information System (INIS)

Cowing, Michelle M.; Elisabeth Pate-Cornell, M.; Glynn, Peter W.

2004-01-01

Short-term tradeoffs between productivity and safety often exist in the operation of critical facilities such as nuclear power plants, offshore oil platforms, or simply individual cars. For example, interruption of operations for maintenance on demand can decrease short-term productivity but may be needed to ensure safety. Operations are interrupted for several reasons: scheduled maintenance, maintenance on demand, response to warnings, subsystem failure, or a catastrophic accident. The choice of operational procedures (e.g. timing and extent of scheduled maintenance) generally affects the probabilities of both production interruptions and catastrophic failures. In this paper, we present and illustrate a dynamic probabilistic model designed to describe the long-term evolution of such a system through the different phases of operation, shutdown, and possibly accident. The model's parameters represent explicitly the effects of different components' performance on the system's safety and reliability through an engineering probabilistic risk assessment (PRA). In addition to PRA, a Markov model is used to track the evolution of the system and its components through different performance phases. The model parameters are then linked to different operations strategies, to allow computation of the effects of each management strategy on the system's long-term productivity and safety. Decision analysis is then used to support the management of the short-term trade-offs between productivity and safety in order to maximize long-term performance. The value function is that of plant managers, within the constraints set by local utility commissions and national (e.g. energy) agencies. This model is illustrated by the case of outages (planned and unplanned) in nuclear power plants to show how it can be used to guide policy decisions regarding outage frequency and plant lifetime, and more specifically, the choice of a reactor tripping policy as a function of the state of the

Trade-offs across space, time, and ecosystem services

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Rodriguez, J.P.; Beard, T.D.; Bennett, E.M.; Cumming, Graeme S.; Cork, S.J.; Agard, J.; Dobson, A.P.; Peterson, G.D.

2006-01-01

Ecosystem service (ES) trade-offs arise from management choices made by humans, which can change the type, magnitude, and relative mix of services provided by ecosystems. Trade-offs occur when the provision of one ES is reduced as a consequence of increased use of another ES. In some cases, a trade-off may be an explicit choice; but in others, trade-offs arise without premeditation or even awareness that they are taking place. Trade-offs in ES can be classified along three axes: spatial scale, temporal scale, and reversibility. Spatial scale refers to whether the effects of the trade-off are felt locally or at a distant location. Temporal scale refers to whether the effects take place relatively rapidly or slowly. Reversibility expresses the likelihood that the perturbed ES may return to its original state if the perturbation ceases. Across all four Millennium Ecosystem Assessment scenarios and selected case study examples, trade-off decisions show a preference for provisioning, regulating, or cultural services (in that order). Supporting services are more likely to be "taken for granted." Cultural ES are almost entirely unquantified in scenario modeling; therefore, the calculated model results do not fully capture losses of these services that occur in the scenarios. The quantitative scenario models primarily capture the services that are perceived by society as more important - provisioning and regulating ecosystem services - and thus do not fully capture trade-offs of cultural and supporting services. Successful management policies will be those that incorporate lessons learned from prior decisions into future management actions. Managers should complement their actions with monitoring programs that, in addition to monitoring the short-term provisions of services, also monitor the long-term evolution of slowly changing variables. Policies can then be developed to take into account ES trade-offs at multiple spatial and temporal scales. Successful strategies will

Trade-offs across Space, Time, and Ecosystem Services

Directory of Open Access Journals (Sweden)

Jon Paul. Rodríguez

2006-06-01

Full Text Available Ecosystem service (ES trade-offs arise from management choices made by humans, which can change the type, magnitude, and relative mix of services provided by ecosystems. Trade-offs occur when the provision of one ES is reduced as a consequence of increased use of another ES. In some cases, a trade-off may be an explicit choice; but in others, trade-offs arise without premeditation or even awareness that they are taking place. Trade-offs in ES can be classified along three axes: spatial scale, temporal scale, and reversibility. Spatial scale refers to whether the effects of the trade-off are felt locally or at a distant location. Temporal scale refers to whether the effects take place relatively rapidly or slowly. Reversibility expresses the likelihood that the perturbed ES may return to its original state if the perturbation ceases. Across all four Millennium Ecosystem Assessment scenarios and selected case study examples, trade-off decisions show a preference for provisioning, regulating, or cultural services (in that order. Supporting services are more likely to be "taken for granted." Cultural ES are almost entirely unquantified in scenario modeling; therefore, the calculated model results do not fully capture losses of these services that occur in the scenarios. The quantitative scenario models primarily capture the services that are perceived by society as more important - provisioning and regulating ecosystem services - and thus do not fully capture trade-offs of cultural and supporting services. Successful management policies will be those that incorporate lessons learned from prior decisions into future management actions. Managers should complement their actions with monitoring programs that, in addition to monitoring the short-term provisions of services, also monitor the long-term evolution of slowly changing variables. Policies can then be developed to take into account ES trade-offs at multiple spatial and temporal scales

The cricket and the ant : Organizational trade-offs in changing environments

NARCIS (Netherlands)

Peli, Gabor; Bruggeman, Jeroen

2007-01-01

Organizations face trade-offs when they adopt strategies in changing resource environments. The type of trade-off depends on the type of resource change. This paper offers an organizational trade-off model for quantitative resource changes. We call it the "Cricket and Ant" (CA) model, because the

Exploring trade-offs between fisheries and conservation of the vaquita porpoise (Phocoena sinus using an Atlantis ecosystem model.

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Hem Nalini Morzaria-Luna

Full Text Available BACKGROUND: Minimizing fishery bycatch threats might involve trade-offs between maintaining viable populations and economic benefits. Understanding these trade-offs can help managers reconcile conflicting goals. An example is a set of bycatch reduction measures for the Critically Endangered vaquita porpoise (Phocoena sinus, in the Northern Gulf of California, Mexico. The vaquita is an endemic species threatened with extinction by artisanal net bycatch within its limited range; in this area fisheries are the chief source of economic productivity. METHODOLOGY/PRINCIPAL FINDINGS: We analyze trade-offs between conservation of the vaquita and fisheries, using an end-to-end Atlantis ecosystem model for the Northern Gulf of California. Atlantis is a spatially-explicit model intended as a strategic tool to test alternative management strategies. We simulated increasingly restrictive fisheries regulations contained in the vaquita conservation plan: implementing progressively larger spatial management areas that exclude gillnets, shrimp driftnets and introduce a fishing gear that has no vaquita bycatch. We found that only the most extensive spatial management scenarios recovered the vaquita population above the threshold necessary to downlist the species from Critically Endangered. The scenario that excludes existing net gear from the 2008 area of vaquita distribution led to moderate decrease in net present value (US$ 42 million relative to the best-performing scenario and a two-fold increase in the abundance of adult vaquita over the course of 30 years. CONCLUSIONS/SIGNIFICANCE: Extended spatial management resulted in the highest recovery of the vaquita population. The economic cost of proposed management actions was unequally divided between fishing fleets; the loss of value from finfish gillnet fisheries was never recovered. Our analysis shows that managers will have to confront difficult trade-offs between management scenarios for vaquita conservation.

Cancer susceptibility and reproductive trade-offs: a model of the evolution of cancer defences.

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Boddy, Amy M; Kokko, Hanna; Breden, Felix; Wilkinson, Gerald S; Aktipis, C Athena

2015-07-19

The factors influencing cancer susceptibility and why it varies across species are major open questions in the field of cancer biology. One underexplored source of variation in cancer susceptibility may arise from trade-offs between reproductive competitiveness (e.g. sexually selected traits, earlier reproduction and higher fertility) and cancer defence. We build a model that contrasts the probabilistic onset of cancer with other, extrinsic causes of mortality and use it to predict that intense reproductive competition will lower cancer defences and increase cancer incidence. We explore the trade-off between cancer defences and intraspecific competition across different extrinsic mortality conditions and different levels of trade-off intensity, and find the largest effect of competition on cancer in species where low extrinsic mortality combines with strong trade-offs. In such species, selection to delay cancer and selection to outcompete conspecifics are both strong, and the latter conflicts with the former. We discuss evidence for the assumed trade-off between reproductive competitiveness and cancer susceptibility. Sexually selected traits such as ornaments or large body size require high levels of cell proliferation and appear to be associated with greater cancer susceptibility. Similar associations exist for female traits such as continuous egg-laying in domestic hens and earlier reproductive maturity. Trade-offs between reproduction and cancer defences may be instantiated by a variety of mechanisms, including higher levels of growth factors and hormones, less efficient cell-cycle control and less DNA repair, or simply a larger number of cell divisions (relevant when reproductive success requires large body size or rapid reproductive cycles). These mechanisms can affect intra- and interspecific variation in cancer susceptibility arising from rapid cell proliferation during reproductive maturation, intrasexual competition and reproduction. © 2015 The Author

Co-existence of multiple trade-off currencies shapes evolutionary outcomes.

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Alan A Cohen

Full Text Available Evolutionary studies often assume that energy is the primary resource (i.e. "currency" at the heart of the survival-reproduction trade-off, despite recent evidence to the contrary. The evolutionary consequences of having a single trade-off currency versus multiple competing currencies are unknown. Using simulations, we modeled the evolution of either a single physiological currency between reproduction and survival, or of multiple such currencies. For a wide array of model specifications varying functional forms and strengths of the trade-offs, we show that the presence of multiple currencies (e.g. nutrients, time generally results in the evolution of higher lifetime reproductive success through partial circumvention of such trade-offs. Evolution of the underlying physiology is also more highly contingent with multiple currencies. These results challenge the paradigm of a single survival-reproduction trade-off as central to life history evolution, suggesting greater roles for physiological constraints and contingency, and implying potential selection for evolution of multiple trade-off currencies.

Co-existence of multiple trade-off currencies shapes evolutionary outcomes

Science.gov (United States)

Isaksson, Caroline; Salguero-Gómez, Roberto

2017-01-01

Evolutionary studies often assume that energy is the primary resource (i.e. “currency”) at the heart of the survival-reproduction trade-off, despite recent evidence to the contrary. The evolutionary consequences of having a single trade-off currency versus multiple competing currencies are unknown. Using simulations, we modeled the evolution of either a single physiological currency between reproduction and survival, or of multiple such currencies. For a wide array of model specifications varying functional forms and strengths of the trade-offs, we show that the presence of multiple currencies (e.g. nutrients, time) generally results in the evolution of higher lifetime reproductive success through partial circumvention of such trade-offs. Evolution of the underlying physiology is also more highly contingent with multiple currencies. These results challenge the paradigm of a single survival-reproduction trade-off as central to life history evolution, suggesting greater roles for physiological constraints and contingency, and implying potential selection for evolution of multiple trade-off currencies. PMID:29216275

Analysis of the tradeoff between agriculture and ecosystem preservation using a new ecohydrological model

Science.gov (United States)

Sun, Z.; Zheng, Y.; Li, X.; Tian, Y.; Zheng, C.

2016-12-01

Inner-basin water use conflicts are common in arid and semi-arid areas. As the second largest endorheic river basin in China, the Heihe River Basin (HRB) is exemplary of such conflicts between agriculture and ecosystem preservation. The densely distributed agriculture in the middle HRB (M-HRB) consumes a large amount of water, which has directly threatened the fragile and water-limited ecosystem in the lower HRB (L-HRB). To alleviate the conflict and prevent the trend of ecological deterioration of the L-HRB, an Ecological Water Diversion Project (EWDP) has been implemented since 2000 to ensure that enough water is released to the L-HRB. With the water diversion, an increase in the leaf area index (LAI) has been observed in the L-HRB. However, to ensure the annually allocated streamflow discharge to the L-HRB, more groundwater (GW) has been pumped for irrigation in the M-HRB, which has led to declining GW levels. How to make water management more sustainable for both agriculture and ecosystem has thus become an urgent issue. Crops and natural vegetation play vital roles in affecting the water cycle, hence it should be well integrated into a hydrological model for water management. A new Hydrological and Ecological Integrated watershed-scale FLOW model (HEIFLOW) has been developed. HEIFLOW is based on an improved version of the GSFLOW developed by the USGS and a General Eco-Hydrological Module (GEHM) developed in this study to simulate plant growth kinetics. The model has been applied to simulate the ecohydrological conditions in the M- and L-HRB. The model results show a consistently good agreement with the observation data. Analysis using the new integrated model indicates that the M-HRB GW system is not sustainable, and that the agriculture in the M-HRB has to sacrifice itself for ecological restoration in the L-HRB under the current water allocation strategy. The restoration of lower basin was further assessed under a new allocation strategy that aims to improve

Use of Tumor Markers in Gastrointestinal Cancers: Surgeon Perceptions and Cost-Benefit Trade-Off Analysis.

Science.gov (United States)

Acharya, Amish; Markar, Sheraz R; Matar, Michael; Ni, Melody; Hanna, George B

2017-05-01

Gastrointestinal cancers constitute the third most common cancers worldwide. Tumor markers have long since been used in the postoperative surveillance of these malignancies; however, the true value in clinical practice remains undetermined. This study aimed to evaluate the clinical utility of three tumor markers in colorectal and esophagogastric cancer. A systematic review of the literature was undertaken to elicit the sensitivity, specificity, statistical heterogeneity and ability to predict recurrence and metastases for carcinoembryonic antigen (CEA), cancer antigen (CA) 19-9 and CA125. European surgeons were surveyed to assess their current practice and the characteristics of tumor markers they most valued. Data from the included studies and survey were combined in a cost-benefit trade-off analysis to assess which tumor markers are of most use in clinical practice. Diagnostic sensitivity and specificity were ranked the most desirable characteristics of a tumor marker by those surveyed. Overall, 156 studies were included to inform the cost-benefit trade-off. The cost-benefit trade-off showed that CEA outperformed both CA19-9 and CA125, with lower financial cost and a higher sensitivity, and diagnostic accuracy for metastases at presentation (area under the curve [AUC] 0.70 vs. 0.61 vs. 0.46), as well as similar diagnostic accuracy for recurrence (AUC 0.46 vs. 0.48). Cost-benefit trade-off analysis identified CEA to be the best performing tumor marker. Further studies should seek to evaluate new tumor markers, with investigation tailored to factors that meet the requirements of practicing clinicians.

Cost-resources trade-off analysis for long-range efficient plutonium consumption

International Nuclear Information System (INIS)

Sato, Osamu; Nakano, Yasuyuki; Yasukawa, Shigeru

1988-01-01

JALTES-III, an analysis model using an optimization technique, is applied to the determination of major requirements for plutonium to serve as fuel for FRR on a paying basis and estimation of the possible reduction in natural uranium consumption. The analysis covers the period from 1970 to 2100. Optimization of the nuclear fuel cycle system is studied by using the following objective functions: overall system cost (COST), natural uranium consumption (NU) and trade-off function (COST + α·NU, where α is the premium related with the price of natural uranium). Assuming that there will be no escalation of the prices of system elements, competitive conditions for FBR are analyzed based on the effective price of natural uranium in relation with the above-mentioned premium: Po + (1 + D) t ·α, where Po is the basic price and D the discount rate. To minimize the term COST, FBR cannot be introduced and the natural uranium consumption will be 2,180,000 tons. To minimize NU, FBR should be introduced to the possible greatest degree, with the estimated natural uranium consumption being 900,000 tons. Analysis is also made of the relations of the introduction of FBRs with the effective price and total consumption of natural uranium. (Nogami, K.)

Tradeoff Analysis for Combat Service Support Wireless Communications Alternatives

Energy Technology Data Exchange (ETDEWEB)

Burnette, John R.; Thibodeau, Christopher C.; Greitzer, Frank L.

2002-02-28

As the Army moves toward more mobile and agile forces and continued sustainment of numerous high-cost legacy logistics management systems, the requirement for wireless connectivity and a wireless network to supporting organizations has become ever more critical. There are currently several Army communications initiatives underway to resolve this wireless connectivity issue. However, to fully appreciate and understand the value of these initiatives, a Tradeoff Analysis is needed. The present study seeks to identify and assess solutions. The analysis identified issues that impede Interim Brigade Combat Team (IBCT) communication system integration and outlined core requirements for sharing of logistics data between the field and Army battle command systems. Then, the analysis examined wireless communication alternatives as possible solutions for IBCT logistics communications problems. The current baseline system was compared with possible alternatives involving tactical radio systems, wireless/near term digital radio, cellular satellite, and third-generation (3G) wireless technologies. Cellular satellite and 3G wireless technologies offer clear advantages and should be considered for later IBCTs.

Trade-off analysis for sustainability evaluation: a case study of the Purhepecha region, Mexico

NARCIS (Netherlands)

Speelman, E.N.; Astier, M.; López Ridaura, S.; Leffelaar, P.A.; Ittersum, van M.K.

2006-01-01

This paper describes the use and role of trade-off analysis as a decision-making tool in the implementation of new technologies and sustainability evaluation. As an example, soils in the Purhepecha region in Mexico have been eroding for decades and crop residue retention has been suggested as an

Constraints, Trade-offs and the Currency of Fitness.

Science.gov (United States)

Acerenza, Luis

2016-03-01

Understanding evolutionary trajectories remains a difficult task. This is because natural evolutionary processes are simultaneously affected by various types of constraints acting at the different levels of biological organization. Of particular importance are constraints where correlated changes occur in opposite directions, called trade-offs. Here we review and classify the main evolutionary constraints and trade-offs, operating at all levels of trait hierarchy. Special attention is given to life history trade-offs and the conflict between the survival and reproduction components of fitness. Cellular mechanisms underlying fitness trade-offs are described. At the metabolic level, a linear trade-off between growth and flux variability was found, employing bacterial genome-scale metabolic reconstructions. Its analysis indicates that flux variability can be considered as the currency of fitness. This currency is used for fitness transfer between fitness components during adaptations. Finally, a discussion is made regarding the constraints which limit the increase in the amount of fitness currency during evolution, suggesting that occupancy constraints are probably the main restrictions.

Analysis of environmental and economic tradeoffs in switchgrass supply chains for biofuel production

International Nuclear Information System (INIS)

Zhong, Jia; Yu, T. Edward; Larson, James A.; English, Burton C.; Fu, Joshua S.; Calcagno, James

2016-01-01

This study considered the environmental advantages of switchgrass, along with the economic challenges in its logistics, in the design of a sustainable switchgrass supply chain in Tennessee. Applying a multi-objective optimization model to high-resolution spatial data, potential tradeoffs among the objectives of minimizing feedstock costs, GHG (greenhouse gas) emissions, and soil erosion were identified for a set of conversion facilities on an efficient frontier. The tradeoff relationship was primarily driven by the type of agricultural land converted to switchgrass. Hay and pasture lands were more cost effective but resulted in higher soil carbon losses and soil erosion after being converted to switchgrass. Converting crop lands reduced GHG emissions and soil erosion but caused higher feedstock cost primarily due to the higher opportunity cost of land use. The respective average costs of abating GHG emissions and soil erosion on the efficient frontier were $2378 Mg"−"1 and $10 Mg"−"1. The compromise solution conversion facility site generated 63% higher feedstock cost compared to the cost minimizing location, while reducing soil erosion by 70 fold and diminishing GHG emissions by 27%. Reducing soil erosion may be a more cost effective environmental criterion than reducing GHG emissions in developing a sustainable switchgrass supply chain in Tennessee. - Highlights: • Multi-objective optimization is applied to a switchgrass supply chain in Tennessee. • Tradeoffs are identified among costs, greenhouse gas, and soil erosion in supply chain. • The type of agricultural land converted to feedstock is a key factor to the tradeoffs. • Abating soil erosion rather than greenhouse gas is more cost effective in Tennessee.

The influence of the composition of tradeoffs on the generation of differentiated cells

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Amado, André; Campos, Paulo R. A.

2017-06-01

We study the emergence of cell differentiation under the influence of tradeoffs between the different functions the cell needs to perform. In the model, the viability of a given colony, i.e. the chance to survive and then form propagules, is determined by the capability of its lower level units to perform different functions. Due to the existence of tradeoffs, it can be evolutionarily advantageous for the colony to evolve the division of labor whereby the cells can suppress their contributions to some of the activities through the activation of regulatory genes. Our simulation results show that cell differentiation is more likely as the number of tradeoffs increases, but the outcome also depends on their strength. We observe the existence of critical values for the minimum number of tradeoffs and their strength beyond that maximum cell differentiation can be attained. The occurrence of a maximum tradeoff strength beyond which the population is no longer viable imposes an upper level of constraint to the system. This maximum tradeoff strength decreases with the number of tradeoffs. Besides the statistical study of the model, as a concrete example, we apply the model to a simplified cyanobacteria system. In this line, variations of this model can be applied to a variety of systems when the underlying tradeoffs are known or can be estimated.

Robust Optimization for Time-Cost Tradeoff Problem in Construction Projects

Directory of Open Access Journals (Sweden)

Ming Li

2014-01-01

Full Text Available Construction projects are generally subject to uncertainty, which influences the realization of time-cost tradeoff in project management. This paper addresses a time-cost tradeoff problem under uncertainty, in which activities in projects can be executed in different construction modes corresponding to specified time and cost with interval uncertainty. Based on multiobjective robust optimization method, a robust optimization model for time-cost tradeoff problem is developed. In order to illustrate the robust model, nondominated sorting genetic algorithm-II (NSGA-II is modified to solve the project example. The results show that, by means of adjusting the time and cost robust coefficients, the robust Pareto sets for time-cost tradeoff can be obtained according to different acceptable risk level, from which the decision maker could choose the preferred construction alternative.

Life History Trade-offs

NARCIS (Netherlands)

Smallegange, I.M.; Kliman, R.M.

2016-01-01

Trade-offs play a central role in life history theory. This article explains why they exist, how they arise, how they can be measured, and briefly discusses their evolution. Three important trade-offs are discussed in detail: the trade-off between current reproduction and survival, between current

Robust Optimization for Time-Cost Tradeoff Problem in Construction Projects

OpenAIRE

Li, Ming; Wu, Guangdong

2014-01-01

Construction projects are generally subject to uncertainty, which influences the realization of time-cost tradeoff in project management. This paper addresses a time-cost tradeoff problem under uncertainty, in which activities in projects can be executed in different construction modes corresponding to specified time and cost with interval uncertainty. Based on multiobjective robust optimization method, a robust optimization model for time-cost tradeoff problem is developed. In order to illus...

Analysis of self-overlap reveals trade-offs in plankton swimming trajectories

DEFF Research Database (Denmark)

Mariani, Patrizio; Visser, Andre W.; Mazzocchi, Maria Grazia

2014-01-01

Movement is a fundamental behaviour of organisms that not only brings about beneficial encounters with resources and mates, but also at the same time exposes the organism to dangerous encounters with predators. The movement patterns adopted by organisms should reflect a balance between...... these contrasting processes. This trade-off can be hypothesized as being evident in the behaviour of plankton, which inhabit a dilute three-dimensional environment with few refuges or orienting landmarks. We present an analysis of the swimming path geometries based on a volumetric Monte Carlo sampling approach...

Dynamical trade-offs arise from antagonistic coevolution and decrease intraspecific diversity.

Science.gov (United States)

Huang, Weini; Traulsen, Arne; Werner, Benjamin; Hiltunen, Teppo; Becks, Lutz

2017-12-12

Trade-offs play an important role in evolution. Without trade-offs, evolution would maximize fitness of all traits leading to a "master of all traits". The shape of trade-offs has been shown to determine evolutionary trajectories and is often assumed to be static and independent of the actual evolutionary process. Here we propose that coevolution leads to a dynamical trade-off. We test this hypothesis in a microbial predator-prey system and show that the bacterial growth-defense trade-off changes from concave to convex, i.e., defense is effective and cheap initially, but gets costly when predators coevolve. We further explore the impact of such dynamical trade-offs by a novel mathematical model incorporating de novo mutations for both species. Predator and prey populations diversify rapidly leading to higher prey diversity when the trade-off is concave (cheap). Coevolution results in more convex (costly) trade-offs and lower prey diversity compared to the scenario where only the prey evolves.

100 Areas soil washing tradeoff study

International Nuclear Information System (INIS)

Belden, R.D.

1995-11-01

The complex nature of cost analysis and systems work demands a level of effort to ensure that decisions made support the best interests of all parties. This tradeoff study will act as a formal decision analysis method for the evaluation of many variables. The documentation of the decision rationale and system design is essential for successful planning and implementation of any system. The Hanford Site offers unique problems for economic analysis of remediation alternatives. The variations in the size of sites, geographic locations, and possible cleanup scenarios all add to the complexity of the tradeoff analysis. A thorough examination of all alternatives must be held to a level of detail appropriate to current regulatory and budgetary considerations. This study will compare the economics of two specific alternatives for remediation of soils at the Hanford Site. Remove and dispose is compared to remove, treat, and dispose. The treatment analyzed in this study is volume reduction through soil washing

Patient centered decision making: use of conjoint analysis to determine risk-benefit trade-offs for preference sensitive treatment choices.

Science.gov (United States)

Wilson, Leslie; Loucks, Aimee; Bui, Christine; Gipson, Greg; Zhong, Lixian; Schwartzburg, Amy; Crabtree, Elizabeth; Goodin, Douglas; Waubant, Emmanuelle; McCulloch, Charles

2014-09-15

Understanding patient preferences facilitates shared decision-making and focuses on patient-centered outcomes. Little is known about relapsing-remitting multiple sclerosis (RRMS) patient preferences for disease modifying therapies (DMTs). We use choice based conjoint (CBC) analysis to calculate patient preferences for risk/benefit trade-offs for hypothetical DMTs. Patients with RRMS were surveyed between 2012 and 2013. Our CBC survey mimicked the decision-making process and trade-offs of patients choosing DMTs, based on all possible DMT attributes. Mixed-effects logistic regression analyzed preferences. We estimated maximum acceptable risk trade-offs for various DMT benefits. Severe side-effect risks had the biggest impact on patient preference with a 1% risk, decreasing patient preference five-fold compared to no risk. (OR=0.22, pbenefit (OR=3.68, pbenefit trade-offs for attributes of all available DMTs. Evaluation of patient preferences is a key step in shared decision making and may significantly impact early drug initiation and compliance. Copyright © 2014 Elsevier B.V. All rights reserved.

Predicting coexistence of plants subject to a tolerance-competition trade-off.

Science.gov (United States)

Haegeman, Bart; Sari, Tewfik; Etienne, Rampal S

2014-06-01

Ecological trade-offs between species are often invoked to explain species coexistence in ecological communities. However, few mathematical models have been proposed for which coexistence conditions can be characterized explicitly in terms of a trade-off. Here we present a model of a plant community which allows such a characterization. In the model plant species compete for sites where each site has a fixed stress condition. Species differ both in stress tolerance and competitive ability. Stress tolerance is quantified as the fraction of sites with stress conditions low enough to allow establishment. Competitive ability is quantified as the propensity to win the competition for empty sites. We derive the deterministic, discrete-time dynamical system for the species abundances. We prove the conditions under which plant species can coexist in a stable equilibrium. We show that the coexistence conditions can be characterized graphically, clearly illustrating the trade-off between stress tolerance and competitive ability. We compare our model with a recently proposed, continuous-time dynamical system for a tolerance-fecundity trade-off in plant communities, and we show that this model is a special case of the continuous-time version of our model.

Land-use change in oil palm dominated tropical landscapes-An agent-based model to explore ecological and socio-economic trade-offs.

Science.gov (United States)

Dislich, Claudia; Hettig, Elisabeth; Salecker, Jan; Heinonen, Johannes; Lay, Jann; Meyer, Katrin M; Wiegand, Kerstin; Tarigan, Suria

2018-01-01

Land-use changes have dramatically transformed tropical landscapes. We describe an ecological-economic land-use change model as an integrated, exploratory tool used to analyze how tropical land-use change affects ecological and socio-economic functions. The model analysis seeks to determine what kind of landscape mosaic can improve the ensemble of ecosystem functioning, biodiversity, and economic benefit based on the synergies and trade-offs that we have to account for. More specifically, (1) how do specific ecosystem functions, such as carbon storage, and economic functions, such as household consumption, relate to each other? (2) How do external factors, such as the output prices of crops, affect these relationships? (3) How do these relationships change when production inefficiency differs between smallholder farmers and learning is incorporated? We initialize the ecological-economic model with artificially generated land-use maps parameterized to our study region. The economic sub-model simulates smallholder land-use management decisions based on a profit maximization assumption. Each household determines factor inputs for all household fields and decides on land-use change based on available wealth. The ecological sub-model includes a simple account of carbon sequestration in above-ground and below-ground vegetation. We demonstrate model capabilities with results on household consumption and carbon sequestration from different output price and farming efficiency scenarios. The overall results reveal complex interactions between the economic and ecological spheres. For instance, model scenarios with heterogeneous crop-specific household productivity reveal a comparatively high inertia of land-use change. Our model analysis even shows such an increased temporal stability in landscape composition and carbon stocks of the agricultural area under dynamic price trends. These findings underline the utility of ecological-economic models, such as ours, to act as

The costs of parental care: a meta-analysis of the trade-off between parental effort and survival in birds.

Science.gov (United States)

Santos, E S A; Nakagawa, S

2012-09-01

A fundamental premise of life-history theory is that organisms that increase current reproductive investment suffer increased mortality. Possibly the most studied life-history phenotypic relationship is the trade-off between parental effort and survival. However, evidence supporting this trade-off is equivocal. Here, we conducted a meta-analysis to test the generality of this tenet. Using experimental studies that manipulated parental effort in birds, we show that (i) the effect of parental effort on survival was similar across species regardless of phylogeny; (ii) individuals that experienced reduced parental effort had similar survival probabilities than control individuals, regardless of sex; and (iii) males that experienced increased parental effort were less likely to survive than control males, whereas females that experienced increased effort were just as likely to survive as control females. Our results suggest that the trade-off between parental effort and survival is more complex than previously assumed. Finally, our study provides recommendations of unexplored avenues of future research into life-history trade-offs. © 2012 The Authors. Journal of Evolutionary Biology © 2012 European Society For Evolutionary Biology.

Module-based analysis of robustness tradeoffs in the heat shock response system.

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Hiroyuki Kurata

2006-07-01

Full Text Available Biological systems have evolved complex regulatory mechanisms, even in situations where much simpler designs seem to be sufficient for generating nominal functionality. Using module-based analysis coupled with rigorous mathematical comparisons, we propose that in analogy to control engineering architectures, the complexity of cellular systems and the presence of hierarchical modular structures can be attributed to the necessity of achieving robustness. We employ the Escherichia coli heat shock response system, a strongly conserved cellular mechanism, as an example to explore the design principles of such modular architectures. In the heat shock response system, the sigma-factor sigma32 is a central regulator that integrates multiple feedforward and feedback modules. Each of these modules provides a different type of robustness with its inherent tradeoffs in terms of transient response and efficiency. We demonstrate how the overall architecture of the system balances such tradeoffs. An extensive mathematical exploration nevertheless points to the existence of an array of alternative strategies for the existing heat shock response that could exhibit similar behavior. We therefore deduce that the evolutionary constraints facing the system might have steered its architecture toward one of many robustly functional solutions.

Interparameter trade-off quantification and reduction in isotropic-elastic full-waveform inversion: synthetic experiments and Hussar land data set application

Science.gov (United States)

Pan, Wenyong; Geng, Yu; Innanen, Kristopher A.

2018-05-01

The problem of inverting for multiple physical parameters in the subsurface using seismic full-waveform inversion (FWI) is complicated by interparameter trade-off arising from inherent ambiguities between different physical parameters. Parameter resolution is often characterized using scattering radiation patterns, but these neglect some important aspects of interparameter trade-off. More general analysis and mitigation of interparameter trade-off in isotropic-elastic FWI is possible through judiciously chosen multiparameter Hessian matrix-vector products. We show that products of multiparameter Hessian off-diagonal blocks with model perturbation vectors, referred to as interparameter contamination kernels, are central to the approach. We apply the multiparameter Hessian to various vectors designed to provide information regarding the strengths and characteristics of interparameter contamination, both locally and within the whole volume. With numerical experiments, we observe that S-wave velocity perturbations introduce strong contaminations into density and phase-reversed contaminations into P-wave velocity, but themselves experience only limited contaminations from other parameters. Based on these findings, we introduce a novel strategy to mitigate the influence of interparameter trade-off with approximate contamination kernels. Furthermore, we recommend that the local spatial and interparameter trade-off of the inverted models be quantified using extended multiparameter point spread functions (EMPSFs) obtained with pre-conditioned conjugate-gradient algorithm. Compared to traditional point spread functions, the EMPSFs appear to provide more accurate measurements for resolution analysis, by de-blurring the estimations, scaling magnitudes and mitigating interparameter contamination. Approximate eigenvalue volumes constructed with stochastic probing approach are proposed to evaluate the resolution of the inverted models within the whole model. With a synthetic

The prevalence, risk factors, and outcomes of medication trade-offs in kidney and liver transplant recipients: a pilot study.

Science.gov (United States)

Serper, Marina; Reese, Peter P; Patzer, Rachel R; Levitsky, Josh; Wolf, Michael S

2017-11-25

High out-of-pocket medication costs negatively impact adherence in transplantation. We evaluated the association of "medication trade-offs"-defined as choosing to spend money on other expenses over medications-with medication nonadherence and transplant outcomes. From 2011 to 2012, we performed a prospective study of 201 transplanted recipients (n = 103 liver, n = 98 kidney and) at two large US transplant centers. Structured interviews assessed socio-demographics, medication adherence, and medication trade-offs. Multivariable models assessing risk factors for medications trade-offs and the association between medications trade-offs and post-transplant hospital admissions were performed. A total of 17% of patients reported medication trade-offs; the most common trade-offs were inability to afford a prescription in the past 12 months and making choices between prescriptions and food. In multivariable analysis, insurance type (RR: 2.97, 95% CI: 1.19-7.40), limited health literacy (RR: 2.64, 95% CI: 1.23-5.64), and ≥3 comorbid conditions (RR: 2.48, 95% CI: 1.09-5.62; all P trade-offs. Patients with trade-offs were more likely to report nonadherence to medications (mean adherence: 77 ± 23% with trade-offs vs. 89 ± 19% without trade-offs, P trade-offs was associated with post-transplant hospital admissions (RR 1.64, 95% CI 1.14-2.35, P < 0.01). Assessments of financial barriers are warranted in clinical practice to identify nonadherence and improve post-transplant outcomes. © 2017 Steunstichting ESOT.

Simbol-X Background Minimization: Mirror Spacecraft Passive Shielding Trade-off Study

Science.gov (United States)

Fioretti, V.; Malaguti, G.; Bulgarelli, A.; Palumbo, G. G. C.; Ferri, A.; Attinà, P.

2009-05-01

The present work shows a quantitative trade-off analysis of the Simbol-X Mirror Spacecraft (MSC) passive shielding, in the phase space of the various parameters: mass budget, dimension, geometry and composition. A simplified physical (and geometrical) model of the sky screen, implemented by means of a GEANT4 simulation, has been developed to perform a performance-driven mass optimization and evaluate the residual background level on Simbol-X focal plane.

Performance trade-offs and ageing in the 'world's greatest athletes'.

Science.gov (United States)

Careau, Vincent; Wilson, Robbie S

2017-08-16

The mechanistic foundations of performance trade-offs are clear: because body size and shape constrains movement, and muscles vary in strength and fibre type, certain physical traits should act in opposition with others (e.g. sprint versus endurance). Yet performance trade-offs are rarely detected, and traits are often positively correlated. A potential resolution to this conundrum is that within -individual performance trade-offs can be masked by among -individual variation in 'quality'. Although there is a current debate on how to unambiguously define and account for quality, no previous studies have partitioned trait correlations at the within- and among-individual levels. Here, we evaluate performance trade-offs among and within 1369 elite athletes that performed in a total of 6418 combined-events competitions (decathlon and heptathlon). Controlling for age, experience and wind conditions, we detected strong trade-offs between groups of functionally similar events (throwing versus jumping versus running) occurring at the among-individual level. We further modelled individual (co)variation in age-related plasticity of performance and found previously unseen trade-offs in throwing versus running performance that manifest through ageing. Our results verify that human performance is limited by fundamental genetic, environmental and ageing constraints that preclude the simultaneous improvement of performance in multiple dimensions. Identifying these constraints is fundamental to understanding performance trade-offs and predicting the ageing of motor function. © 2017 The Author(s).

Managing trade-offs in landscape restoration and revegetation projects.

Science.gov (United States)

Maron, Martine; Cockfield, Geoff

2008-12-01

Landscape restoration projects often have multiple and disparate conservation, resource enhancement, and sometimes economic objectives, since projects that seek to meet more than one objective tend to be viewed more positively by funding agencies and the community. The degree to which there are trade-offs among desired objectives is an important variable for decision makers, yet this is rarely explicitly considered. In particular, the existence of ecological thresholds has important implications for decision-making at both the project level and the regional level. We develop a model of the possibilities and choices for an agency seeking to achieve two environmental objectives in a region through revegetation of a number of sites. A graphical model of the production possibilities sets for a single revegetation project is developed, and different trade-off relationships are discussed and illustrated. Then the model is used to demonstrate the possibilities for managing all such projects within a region. We show that, where there are thresholds in the trade-off relationship between two objectives, specialization (single- or dominant-objective projects) should be considered. This is illustrated using a case study in which revegetation is used to meet avian biodiversity and salinity mitigation objectives. We conclude that where there are sufficient scientific data, explicit consideration of different types of trade-offs can assist in making decisions about the most efficient mix and type of projects to better achieve a range of objectives within a region.

QR-GARCH-M Model for Risk-Return Tradeoff in U.S. Stock Returns and Business Cycles

OpenAIRE

Nyberg, Henri

2010-01-01

In the empirical finance literature findings on the risk return tradeoff in excess stock market returns are ambiguous. In this study, we develop a new QR-GARCH-M model combining a probit model for a binary business cycle indicator and a regime switching GARCH-in-mean model for excess stock market return with the business cycle indicator defining the regime. Estimation results show that there is statistically significant variation in the U.S. excess stock returns over the business cycle. Howev...

A Multi-Objective Trade-Off Model in Sustainable Construction Projects

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Guangdong Wu

2017-10-01

Full Text Available Based on the consideration of the relative importance of sustainability-related objectives and the inherent nature of sustainable construction projects, this study proposes that the contractor can balance the levels of efforts and resources used to improve the overall project sustainability. A multi-objective trade-off model using game theory was established and verified through simulation and numerical example under a moral hazard situation. Results indicate that effort levels of the contractor on sustainability-related objectives are positively related to the outcome coefficient while negatively to the coefficients of effort cost of the relevant objectives. High levels of the relative importance of sustainability-related objectives contribute to high levels of effort of the contractor. With the variation in effort levels and the coefficient of benefit allocation, the project net benefit increases before declining. The function of project benefit has a marked peak value, with an inverted “U” shape. An equilibrium always exists as for the given relative importance and coefficients of the effort costs of sustainability-related objectives. Under this condition, the owner may offer the contractor a less intense incentive and motivate the contractor reasonably arranging input resources. The coefficient of benefit allocation is affected by the contractor characteristic factors and the project characteristic factors. The owner should balance these two types of factors and select the most appropriate incentive mechanism to improve the project benefit. Meanwhile, the contractor can balance the relative importance of the objectives and arrange the appropriate levels of effort and resources to achieve a sustainability-related objective. Very few studies have emphasized the effects of the relative importance of sustainability-related objectives on the benefits of sustainable construction projects. This study therefore builds a multi-objective trade-off

Trade-off analysis in the Northern Andes to study the dynamics in agricultural land use

NARCIS (Netherlands)

Stoorvogel, J.J.; Antle, J.M.; Crissman, C.C.

2004-01-01

In this paper we hypothesize that land use change can be induced by non-linearities and thresholds in production systems that impact farmers' decision making. Tradeoffs between environmental and economic indicators is a useful way to represent dynamic properties of agricultural systems. The Tradeoff

Dissociable mechanisms of speed-accuracy tradeoff during visual perceptual learning are revealed by a hierarchical drift diffusion model

Directory of Open Access Journals (Sweden)

Jiaxiang eZhang

2014-04-01

Full Text Available Two phenomena are commonly observed in decision-making. First, there is a speed-accuracy tradeoff such that decisions are slower and more accurate when instructions emphasize accuracy over speed, and vice versa. Second, decision performance improves with practice, as a task is learnt. The speed-accuracy tradeoff and learning effects have been explained under a well-established evidence-accumulation framework for decision-making, which suggests that evidence supporting each choice is accumulated over time, and a decision is committed to when the accumulated evidence reaches a decision boundary. This framework suggests that changing the decision boundary creates the tradeoff between decision speed and accuracy, while increasing the rate of accumulation leads to more accurate and faster decisions after learning. However, recent studies challenged the view that speed-accuracy tradeoff and learning are associated with changes in distinct, single decision parameters. Further, the influence of speed-accuracy instructions over the course of learning remains largely unknown. Here, we used a hierarchical drift-diffusion model to examine the speed-accuracy tradeoff during learning of a coherent motion discrimination task across multiple training sessions, and a transfer test session. The influence of speed-accuracy instructions was robust over training and generalized across untrained stimulus features. Emphasizing decision accuracy rather than speed was associated with increased boundary separation, drift rate and non-decision time at the beginning of training. However, after training, an emphasis on decision accuracy was only associated with increased boundary separation. In addition, faster and more accurate decisions after learning were due to a gradual decrease in boundary separation and an increase in drift rate. The results suggest that speed-accuracy instructions and learning differentially shape decision-making processes at different time scales.

Trait-fitness relationships determine how trade-off shapes affect species coexistence.

Science.gov (United States)

Ehrlich, Elias; Becks, Lutz; Gaedke, Ursula

2017-12-01

Trade-offs between functional traits are ubiquitous in nature and can promote species coexistence depending on their shape. Classic theory predicts that convex trade-offs facilitate coexistence of specialized species with extreme trait values (extreme species) while concave trade-offs promote species with intermediate trait values (intermediate species). We show here that this prediction becomes insufficient when the traits translate non-linearly into fitness which frequently occurs in nature, e.g., an increasing length of spines reduces grazing losses only up to a certain threshold resulting in a saturating or sigmoid trait-fitness function. We present a novel, general approach to evaluate the effect of different trade-off shapes on species coexistence. We compare the trade-off curve to the invasion boundary of an intermediate species invading the two extreme species. At this boundary, the invasion fitness is zero. Thus, it separates trait combinations where invasion is or is not possible. The invasion boundary is calculated based on measurable trait-fitness relationships. If at least one of these relationships is not linear, the invasion boundary becomes non-linear, implying that convex and concave trade-offs not necessarily lead to different coexistence patterns. Therefore, we suggest a new ecological classification of trade-offs into extreme-favoring and intermediate-favoring which differs from a purely mathematical description of their shape. We apply our approach to a well-established model of an empirical predator-prey system with competing prey types facing a trade-off between edibility and half-saturation constant for nutrient uptake. We show that the survival of the intermediate prey depends on the convexity of the trade-off. Overall, our approach provides a general tool to make a priori predictions on the outcome of competition among species facing a common trade-off in dependence of the shape of the trade-off and the shape of the trait

A dynamic model to assess tradeoffs in power production and riverine ecosystem protection.

Science.gov (United States)

Miara, Ariel; Vörösmarty, Charles J

2013-06-01

Major strategic planning decisions loom as society aims to balance energy security, economic development and environmental protection. To achieve such balance, decisions involving the so-called water-energy nexus must necessarily embrace a regional multi-power plant perspective. We present here the Thermoelectric Power & Thermal Pollution Model (TP2M), a simulation model that simultaneously quantifies thermal pollution of rivers and estimates efficiency losses in electricity generation as a result of fluctuating intake temperatures and river flows typically encountered across the temperate zone. We demonstrate the model's theoretical framework by carrying out sensitivity tests based on energy, physical and environmental settings. We simulate a series of five thermoelectric plants aligned along a hypothetical river, where we find that warm ambient temperatures, acting both as a physical constraint and as a trigger for regulatory limits on plant operations directly reduce electricity generation. As expected, environmental regulation aimed at reducing thermal loads at a single plant reduces power production at that plant, but ironically can improve the net electricity output from multiple plants when they are optimally co-managed. On the technology management side, high efficiency can be achieved through the use of natural gas combined cycle plants, which can raise the overall efficiency of the aging population of plants, including that of coal. Tradeoff analysis clearly shows the benefit of attaining such high efficiencies, in terms of both limiting thermal loads that preserve ecosystem services and increasing electricity production that benefits economic development.

Diversity-Multiplexing-Nulling Trade-Off Analysis of Multiuser MIMO System for Intercell Interference Coordination

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Jinwoo Kim

2017-01-01

Full Text Available A fundamental performance trade-off of multicell multiuser multiple-input multiple-output (MU-MIMO systems is explored for achieving intercell and intracell interference-free conditions. In particular, we analyze the three-dimensional diversity-multiplexing-nulling trade-off (DMNT among the diversity order (i.e., the slope of the error performance curve, multiplexing order (i.e., the number of users that are simultaneously served by MU-MIMO, and nulling order (i.e., the number of users with zero interference in a victim cell. This trade-off quantifies the performance of MU-MIMO in terms of its diversity and multiplexing order, while nulling the intercell interference toward the victim cell in the neighbor. First, we design a precoding matrix to mitigate both intercell and intracell interference for a linear precoding-based MU-MIMO system. Then, the trade-off relationship is obtained by analyzing the distribution of the signal-to-noise ratio (SNR at the user terminals. Furthermore, we demonstrate how DMNT can be applied to estimate the long-term throughput for each mobile station, which allows for determining the optimal number of multiplexing order and throughput loss due to the interference nulling.

Understanding performance properties of chemical engines under a trade-off optimization: Low-dissipation versus endoreversible model

Science.gov (United States)

Tang, F. R.; Zhang, Rong; Li, Huichao; Li, C. N.; Liu, Wei; Bai, Long

2018-05-01

The trade-off criterion is used to systemically investigate the performance features of two chemical engine models (the low-dissipation model and the endoreversible model). The optimal efficiencies, the dissipation ratios, and the corresponding ratios of the dissipation rates for two models are analytically determined. Furthermore, the performance properties of two kinds of chemical engines are precisely compared and analyzed, and some interesting physics is revealed. Our investigations show that the certain universal equivalence between two models is within the framework of the linear irreversible thermodynamics, and their differences are rooted in the different physical contexts. Our results can contribute to a precise understanding of the general features of chemical engines.

Assessing trade-offs in large marine protected areas.

Science.gov (United States)

Davies, Tammy E; Epstein, Graham; Aguilera, Stacy E; Brooks, Cassandra M; Cox, Michael; Evans, Louisa S; Maxwell, Sara M; Nenadovic, Mateja; Ban, Natalie C

2018-01-01

Large marine protected areas (LMPAs) are increasingly being established and have a high profile in marine conservation. LMPAs are expected to achieve multiple objectives, and because of their size are postulated to avoid trade-offs that are common in smaller MPAs. However, evaluations across multiple outcomes are lacking. We used a systematic approach to code several social and ecological outcomes of 12 LMPAs. We found evidence of three types of trade-offs: trade-offs between different ecological resources (supply trade-offs); trade-offs between ecological resource conditions and the well-being of resource users (supply-demand trade-offs); and trade-offs between the well-being outcomes of different resource users (demand trade-offs). We also found several divergent outcomes that were attributed to influences beyond the scope of the LMPA. We suggest that despite their size, trade-offs can develop in LMPAs and should be considered in planning and design. LMPAs may improve their performance across multiple social and ecological objectives if integrated with larger-scale conservation efforts.

Using the Sustainability Monitoring and Assessment Routine (SMART for the Systematic Analysis of Trade-Offs and Synergies between Sustainability Dimensions and Themes at Farm Level

Directory of Open Access Journals (Sweden)

Christian Schader

2016-03-01

Full Text Available When trying to optimize the sustainability performance of farms and farming systems, a consideration of trade-offs and synergies between different themes and dimensions is required. The aim of this paper is to perform a systematic analysis of trade-offs and synergies across all dimensions and themes. To achieve this aim we used the Sustainability Monitoring and Assessment Routine (SMART-Farm Tool which operationalizes the Sustainability Assessment of Food and Agriculture Systems (SAFA Guidelines by defining science-based indicator sets and assessment procedures. It identifies the degree of goal achievement with respect to the 58 themes defined in the SAFA Guidelines using an impact matrix that defines 327 indicators and 1769 relations between sustainability themes and indicators. We illustrate how the SMART-Farm Tool can be successfully applied to assess the sustainability performance of farms of different types and in different geographic regions. Our analysis revealed important synergies between themes within a sustainability dimension and across dimensions. We found major trade-offs within the environmental dimension and between the environmental and economic dimension. The trade-offs within the environmental dimension were even larger than the trade-offs with other dimensions. The study also underlines the importance of the governance dimension with regard to achieving a good level of performance in the other dimensions.

A comparison of carbon allocation schemes: On the equity-efficiency tradeoff

International Nuclear Information System (INIS)

Pan, Xunzhang; Teng, Fei; Wang, Gehua

2014-01-01

In the long-term stabilization targets of greenhouse gases concentrations, various carbon emission rights allocation schemes have been proposed. To compare and evaluate them, the most essential is the equity-efficiency tradeoff. This paper measures the equity and the efficiency in the global rather than the narrower national perspective. Specifically, the equity of the first allocation is quantified by the carbon Gini coefficient defined by per capita cumulative emission, and the economic efficiency to accomplish obligations is described with the discounted global abatement costs. Under 20 key allocation schemes, the numerical comparison on the equity-efficiency tradeoff side is carried out through the Equitable Access to Sustainable Development model. Our studies indicate that the equity and the efficiency of future emission space allocation approximately show a three-stage relationship. - Highlights: • The equity-efficiency tradeoff among 20 key allocation schemes is carried out. • Both the equity and the efficiency are measured in the global perspective. • The Equitable Access to Sustainable Development model is adopted as the study tool. • A practical trade framework is indispensable to efficiently address climate change. • The equity and the efficiency generally show a three-stage tradeoff relationship

Demographic trade-offs in a neutral model explain death-rate--abundance-rank relationship.

Science.gov (United States)

Lin, Kui; Zhang, Da-Yong; He, Fangliang

2009-01-01

The neutral theory of biodiversity has been criticized for its neglect of species differences. Yet it is much less heeded that S. P. Hubbell's definition of neutrality allows species to differ in their birth and death rates as long as they have an equal per capita fitness. Using the lottery model of competition we find that fitness equalization through birth-death trade-offs can make species coexist longer than expected for demographically identical species, whereas the probability of monodominance for a species under zero-sum neutral dynamics is equal to its initial relative abundance. Furthermore, if newly arising species in a community survive preferentially they are more likely to slip through the quagmire of rareness, thus creating a strong selective bias favoring their community membership. On the other hand, high-mortality species, once having gained a footing in the community, are more likely to become abundant due to their compensatory high birth rates. This unexpected result explains why a positive association between species abundance and per capita death rate can be seen in tropical-forest communities. An explicit incorporation of interspecific trade-offs between birth and death into the neutral theory increases the theory's realism as well as its predictive power.

Tradeoffs Between Branch Mispredictions and Comparisons for Sorting Algorithms

DEFF Research Database (Denmark)

Brodal, Gerth Stølting; Moruz, Gabriel

2005-01-01

Branch mispredictions is an important factor affecting the running time in practice. In this paper we consider tradeoffs between the number of branch mispredictions and the number of comparisons for sorting algorithms in the comparison model. We prove that a sorting algorithm using O(dnlog n......) comparisons performs Omega(nlogd n) branch mispredictions. We show that Multiway MergeSort achieves this tradeoff by adopting a multiway merger with a low number of branch mispredictions. For adaptive sorting algorithms we similarly obtain that an algorithm performing O(dn(1+log (1+Inv/n))) comparisons must...... perform Omega(nlogd (1+Inv/n)) branch mispredictions, where Inv is the number of inversions in the input. This tradeoff can be achieved by GenericSort by Estivill-Castro and Wood by adopting a multiway division protocol and a multiway merging algorithm with a low number of branch mispredictions....

Features of spatial and functional segregation and integration of the primate connectome revealed by trade-off between wiring cost and efficiency.

Science.gov (United States)

Chen, Yuhan; Wang, Shengjun; Hilgetag, Claus C; Zhou, Changsong

2017-09-01

The primate connectome, possessing a characteristic global topology and specific regional connectivity profiles, is well organized to support both segregated and integrated brain function. However, the organization mechanisms shaping the characteristic connectivity and its relationship to functional requirements remain unclear. The primate brain connectome is shaped by metabolic economy as well as functional values. Here, we explored the influence of two competing factors and additional advanced functional requirements on the primate connectome employing an optimal trade-off model between neural wiring cost and the representative functional requirement of processing efficiency. Moreover, we compared this model with a generative model combining spatial distance and topological similarity, with the objective of statistically reproducing multiple topological features of the network. The primate connectome indeed displays a cost-efficiency trade-off and that up to 67% of the connections were recovered by optimal combination of the two basic factors of wiring economy and processing efficiency, clearly higher than the proportion of connections (56%) explained by the generative model. While not explicitly aimed for, the trade-off model captured several key topological features of the real connectome as the generative model, yet better explained the connectivity of most regions. The majority of the remaining 33% of connections unexplained by the best trade-off model were long-distance links, which are concentrated on few cortical areas, termed long-distance connectors (LDCs). The LDCs are mainly non-hubs, but form a densely connected group overlapping on spatially segregated functional modalities. LDCs are crucial for both functional segregation and integration across different scales. These organization features revealed by the optimization analysis provide evidence that the demands of advanced functional segregation and integration among spatially distributed regions may

Behavioral tradeoffs when dispersing across a patchy landscape.

Science.gov (United States)

Patrick A. Zollner; Steven L. Lima

2005-01-01

A better understanding of the behavior of dispersing animals will assist in determining the factors that limit their success and ultimately help improve the way dispersal is incorporated into population models. To that end, we used a simulation model to investigate three questions about behavioral tradeoffs that dispersing animals might face: (i) speed of movement...

Trade-offs between Energy Efficiency improvements and additional Renewable Energy supply: A review of international experiences

DEFF Research Database (Denmark)

Baldini, Mattia; Klinge Jacobsen, Henrik

improvements made in the energy saving field. Indeed, less attention has been paid to implement energy efficiency measures in energy systems modeling, which has resulted in scenarios where expedients for a wise use of energy (e.g. energy savings and renewables’ share) are unbalanced and cost......-savings opportunities are missed. The aim of this paper is to review and evaluate international experiences on finding the optimal trade-off between efficiency improvements and additional renewable energy supply. A critical review of each technique, focusing on purposes, methodology and outcomes, is provided along......-makers, informations useful for identify a suitable analysis for investigate on the optimal trade-off between renewables and energy efficiency measures in energy-systems under different objectives....

48 CFR 15.101-1 - Tradeoff process.

Science.gov (United States)

2010-10-01

... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Tradeoff process. 15.101-1... AND CONTRACT TYPES CONTRACTING BY NEGOTIATION Source Selection Processes and Techniques 15.101-1 Tradeoff process. (a) A tradeoff process is appropriate when it may be in the best interest of the...

Dengeleme Teorisi’nin Geçerliliğinin Panel Veri Analizi ile Test Edilmesi: BİST’de Ampirik Bir Uygulama(Testing the Validity of Trade-Off Theory by Using Panel Regression Analysis: An Empirical Application on ISE

Directory of Open Access Journals (Sweden)

İbrahim BOZKURT

2014-12-01

Full Text Available The aim of this study is to test the validity of Trade-Off theory by investigating the relationship between capital structures and market values of firms on ISE. In this study, 127.008 financial ratio, 20.664 monthly stock return, 4.704 market value and debt ratio which are belong to 168 firms traded on ISE between 2005 and 2011 is used. Firstly, efficient model predicting bankruptcy is confirmed by using balanced panel regression analysis for ISE. Secondly, by using efficient model, firms are divided two groups that consist of firms which have or not bankruptcy risk for each period and the relationship market values and debt levels of firms in each group is analyzed by using unbalanced panel regression analysis. The results of the analysis reveal that there is positive relationship between market values and debt levels of firms in terms of both groups. This result implies that Trade-Off theory is not validity on ISE.

Earth Observatory Satellite system definition study. Report 3: Design cost trade-off studies and recommendations

Science.gov (United States)

1974-01-01

An analysis of the design and cost tradeoff aspects of the Earth Observatory Satellite (EOS) development is presented. The design/cost factors that affect a series of mission/system level concepts are discussed. The subjects considered are as follows: (1) spacecraft subsystem cost tradeoffs, (2) ground system cost tradeoffs, and (3) program cost summary. Tables of data are provided to summarize the results of the analyses. Illustrations of the various spacecraft configurations are included.

Conceptualising and managing trade-offs in sustainability assessment

International Nuclear Information System (INIS)

Morrison-Saunders, Angus; Pope, Jenny

2013-01-01

One of the defining characteristics of sustainability assessment as a form of impact assessment is that it provides a forum for the explicit consideration of the trade-offs that are inherent in complex decision-making processes. Few sustainability assessments have achieved this goal though, and none has considered trade-offs in a holistic fashion throughout the process. Recent contributions such as the Gibson trade-off rules have significantly progressed thinking in this area by suggesting appropriate acceptability criteria for evaluating substantive trade-offs arising from proposed development, as well as process rules for how evaluations of acceptability should occur. However, there has been negligible uptake of these rules in practice. Overall, we argue that there is inadequate consideration of trade-offs, both process and substantive, throughout the sustainability assessment process, and insufficient considerations of how process decisions and compromises influence substantive outcomes. This paper presents a framework for understanding and managing both process and substantive trade-offs within each step of a typical sustainability assessment process. The framework draws together previously published literature and offers case studies that illustrate aspects of the practical application of the framework. The framing and design of sustainability assessment are vitally important, as process compromises or trade-offs can have substantive consequences in terms of sustainability outcomes delivered, with the choice of alternatives considered being a particularly significant determinant of substantive outcomes. The demarcation of acceptable from unacceptable impacts is a key aspect of managing trade-offs. Offsets can be considered as a form of trade-off within a category of sustainability that are utilised to enhance preferred alternatives once conditions of impact acceptability have been met. In this way they may enable net gains to be delivered; another imperative

Conceptualising and managing trade-offs in sustainability assessment

Energy Technology Data Exchange (ETDEWEB)

Morrison-Saunders, Angus, E-mail: A.Morrison-Saunders@murdoch.edu.au [School of Geo and Spatial Sciences, North West University (South Africa); School of Environmental Science, Murdoch University (Australia); Pope, Jenny [School of Geo and Spatial Sciences, North West University (South Africa); Integral Sustainability (Australia); Curtin University (Australia)

2013-01-15

One of the defining characteristics of sustainability assessment as a form of impact assessment is that it provides a forum for the explicit consideration of the trade-offs that are inherent in complex decision-making processes. Few sustainability assessments have achieved this goal though, and none has considered trade-offs in a holistic fashion throughout the process. Recent contributions such as the Gibson trade-off rules have significantly progressed thinking in this area by suggesting appropriate acceptability criteria for evaluating substantive trade-offs arising from proposed development, as well as process rules for how evaluations of acceptability should occur. However, there has been negligible uptake of these rules in practice. Overall, we argue that there is inadequate consideration of trade-offs, both process and substantive, throughout the sustainability assessment process, and insufficient considerations of how process decisions and compromises influence substantive outcomes. This paper presents a framework for understanding and managing both process and substantive trade-offs within each step of a typical sustainability assessment process. The framework draws together previously published literature and offers case studies that illustrate aspects of the practical application of the framework. The framing and design of sustainability assessment are vitally important, as process compromises or trade-offs can have substantive consequences in terms of sustainability outcomes delivered, with the choice of alternatives considered being a particularly significant determinant of substantive outcomes. The demarcation of acceptable from unacceptable impacts is a key aspect of managing trade-offs. Offsets can be considered as a form of trade-off within a category of sustainability that are utilised to enhance preferred alternatives once conditions of impact acceptability have been met. In this way they may enable net gains to be delivered; another imperative

Privacy versus autonomy: a tradeoff model for smart home monitoring technologies.

Science.gov (United States)

Townsend, Daphne; Knoefel, Frank; Goubran, Rafik

2011-01-01

Smart homes are proposed as a new location for the delivery of healthcare services. They provide healthcare monitoring and communication services, by using integrated sensor network technologies. We validate a hypothesis regarding older adults' adoption of home monitoring technologies by conducting a literature review of articles studying older adults' attitudes and perceptions of sensor technologies. Using current literature to support the hypothesis, this paper applies the tradeoff model to decisions about sensor acceptance. Older adults are willing to trade privacy (by accepting a monitoring technology), for autonomy. As the information captured by the sensor becomes more intrusive and the infringement on privacy increases, sensors are accepted if the loss in privacy is traded for autonomy. Even video cameras, the most intrusive sensor type were accepted in exchange for the height of autonomy which is to remain in the home.

Cancer and Longevity--Is There a Trade-off?

DEFF Research Database (Denmark)

Christensen, Kaare; Pedersen, Jacob K; Hjelmborg, Jacob V B

2012-01-01

Animal models and a few human studies have suggested a complex interaction between cancer risk and longevity indicating a trade-off where low cancer risk is associated with accelerating aging phenotypes and, vice versa, that longevity potential comes with the cost of increased cancer risk...

Trade-Off and Synergy among Ecosystem Services in the Guanzhong-Tianshui Economic Region of China.

Science.gov (United States)

Qin, Keyu; Li, Jing; Yang, Xiaonan

2015-11-03

Natural ecosystems provide society with important goods and services. With rapidly increasing populations and excessive utilization of natural resources, humans have been enhancing the production of some services at the expense of others. Although the need for certain trade-offs between conservation and development is urgent, having only a small number of efficient methods to assess such trade-offs has impeded progress. This study focuses on the evaluation of ecosystem services under different land use schemes. It reveals the spatial and temporal distributions of and changes in ecosystem services. Based on a correlation rate model and distribution mapping, the trade-offs and synergies of these ecosystem services can be found. Here, we also describe a new simple approach to quantify the relationships of every trade-off and synergy. The results show that all ecosystem services possess trade-offs and synergies in the study area. The trend of improving carbon sequestration and water interception indicate that these key ecosystem services have the strongest synergy. And the decrease in regional agricultural production and other services, except water yield, may be considered as trade-offs. The synergy between water yield and agricultural production was the most significant, while the trade-off between water interception and carbon sequestration was the most apparent, according to our interaction quantification model. The results of this study have implications for planning and monitoring the future management of natural capital and ecosystem services, and can be integrated into land use decision-making.

Trade-Off and Synergy among Ecosystem Services in the Guanzhong-Tianshui Economic Region of China

Directory of Open Access Journals (Sweden)

Keyu Qin

2015-11-01

Full Text Available Natural ecosystems provide society with important goods and services. With rapidly increasing populations and excessive utilization of natural resources, humans have been enhancing the production of some services at the expense of others. Although the need for certain trade-offs between conservation and development is urgent, having only a small number of efficient methods to assess such trade-offs has impeded progress. This study focuses on the evaluation of ecosystem services under different land use schemes. It reveals the spatial and temporal distributions of and changes in ecosystem services. Based on a correlation rate model and distribution mapping, the trade-offs and synergies of these ecosystem services can be found. Here, we also describe a new simple approach to quantify the relationships of every trade-off and synergy. The results show that all ecosystem services possess trade-offs and synergies in the study area. The trend of improving carbon sequestration and water interception indicate that these key ecosystem services have the strongest synergy. And the decrease in regional agricultural production and other services, except water yield, may be considered as trade-offs. The synergy between water yield and agricultural production was the most significant, while the trade-off between water interception and carbon sequestration was the most apparent, according to our interaction quantification model. The results of this study have implications for planning and monitoring the future management of natural capital and ecosystem services, and can be integrated into land use decision-making.

Time and Outcome Framing in Intertemporal Tradeoffs

Science.gov (United States)

Scholten, Marc; Read, Daniel

2013-01-01

A robust anomaly in intertemporal choice is the delay-speedup asymmetry: Receipts are discounted more, and payments are discounted less, when delayed than when expedited over the same interval. We developed 2 versions of the tradeoff model (Scholten & Read, 2010) to address such situations, in which an outcome is expected at a given time but…

The hare or the tortoise? Modeling optimal speed-accuracy tradeoff settings

NARCIS (Netherlands)

van Ravenzwaaij, D.

2012-01-01

Decision making is strongly influenced by the speed-accuracy trade-off. In this dissertation, I have tackled the issue of speed versus accuracy from both a theoretical and an empirical viewpoint and have been drawn time and time again to the same inescapable conclusion: speeded decision making

Electric-powered passenger vehicle design study program. Task 1. Tradeoff studies

Energy Technology Data Exchange (ETDEWEB)

Rowlett, B.H.

1976-09-16

Using the baseline vehicle and power system design established previously to meet the performance goals of the program, three power system computer simulation programs were prepared for the basic vehicle tradeoff studies. These programs simulate the performance of the power system and vehicle over different types of driving conditions such as maximum power acceleration, deceleration, city driving cycles, and hill climbing, and permit accurate determination of the benefits of the unique hybrid power system, the total energy required for the suburban city driving cycle, and the extremes of the operating envelopes of the components so that component design options can be defined and studied. Component design tradeoff studies were conducted, including sensitivity studies to show the criticality of the various losses and unknowns in the analytical models. Also, preliminary vehicle layout studies were performed to determine the best locations of the power system and the batteries. Three basic design options are identified for further study. Economic studies were initiated using analytical models to establish the complete vehicle weight and cost breakdowns. Preliminary reliability and safety studies were completed, and maintainability and safety certification criteria established. The detailed analysis of the power system has verified the feasibility of the system and of the performance expectations. Also, the feasibility of energy recovery from regenerative braking has been confirmed. The sensitivity analysis of the power system shows that sufficient margin for unknown design variables is provided. The preliminary economic analysis indicates that the most difficult objective of the study will be the selection of the cost and weight relationships which are required to achieve the overall cost objectives.

Value tradeoffs for the Hanford Tank Waste Remediation System (TWRS) program

Energy Technology Data Exchange (ETDEWEB)

Keeney, R.L.; Winterfeldt, D. von [Decision Insights, Inc., Irvine, CA (United States)

1997-09-01

The Tank Waste Remediation System (TWRS) program at the Hanford Site of the Department of Energy has adopted a logical approach to making decisions that uses decision analysis to structure and analyze decision alternatives and public values to evaluate them. This report is the third in a series to support this effort. The first identified a set of objectives (called {open_quotes}ends objectives{close_quotes}) that characterize the ultimate goals and desires of Hanford decision makers and stakeholders. The second report developed operational measures for these ends objectives (called {open_quotes}ends measures{close_quotes}) and it also developed a set of performance objectives and associated performance measures that are more directly related to how well decision alternatives in the TWRS program perform to achieve the ends objectives. The present report describes the development of quantitative value tradeoffs for both the ends measures and the performance measures. First, five national value experts were interviewed to obtain value tradeoffs for units of the ends measures identified in Keeney and von Winterfeldt (1996). The results of this assessment are shown in Table S1. Second, the implied value tradeoffs for the units of the performance measures were calculated from the value tradeoffs for units of the ends measures provided by the national experts. When calculating the value tradeoffs for the units of the performance measures, very simple quantitative relationships between ends and performance measures were assumed. The results of this calculation are shown in Table S2. The results of this report shown in Tables S1 and S2 should be considered preliminary and largely illustrative of the principles for developing value tradeoffs. The report lists several important caveats and recommendations for how future work can improve on the assessment of value tradeoffs.

Features of spatial and functional segregation and integration of the primate connectome revealed by trade-off between wiring cost and efficiency.

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Yuhan Chen

2017-09-01

Full Text Available The primate connectome, possessing a characteristic global topology and specific regional connectivity profiles, is well organized to support both segregated and integrated brain function. However, the organization mechanisms shaping the characteristic connectivity and its relationship to functional requirements remain unclear. The primate brain connectome is shaped by metabolic economy as well as functional values. Here, we explored the influence of two competing factors and additional advanced functional requirements on the primate connectome employing an optimal trade-off model between neural wiring cost and the representative functional requirement of processing efficiency. Moreover, we compared this model with a generative model combining spatial distance and topological similarity, with the objective of statistically reproducing multiple topological features of the network. The primate connectome indeed displays a cost-efficiency trade-off and that up to 67% of the connections were recovered by optimal combination of the two basic factors of wiring economy and processing efficiency, clearly higher than the proportion of connections (56% explained by the generative model. While not explicitly aimed for, the trade-off model captured several key topological features of the real connectome as the generative model, yet better explained the connectivity of most regions. The majority of the remaining 33% of connections unexplained by the best trade-off model were long-distance links, which are concentrated on few cortical areas, termed long-distance connectors (LDCs. The LDCs are mainly non-hubs, but form a densely connected group overlapping on spatially segregated functional modalities. LDCs are crucial for both functional segregation and integration across different scales. These organization features revealed by the optimization analysis provide evidence that the demands of advanced functional segregation and integration among spatially

The rate-size trade-off structures intraspecific variation in Daphnia ambigua life history parameters.

Science.gov (United States)

DeLong, John P; Hanley, Torrance C

2013-01-01

The identification of trade-offs is necessary for understanding the evolution and maintenance of diversity. Here we employ the supply-demand (SD) body size optimization model to predict a trade-off between asymptotic body size and growth rate. We use the SD model to quantitatively predict the slope of the relationship between asymptotic body size and growth rate under high and low food regimes and then test the predictions against observations for Daphnia ambigua. Close quantitative agreement between observed and predicted slopes at both food levels lends support to the model and confirms that a 'rate-size' trade-off structures life history variation in this population. In contrast to classic life history expectations, growth and reproduction were positively correlated after controlling for the rate-size trade-off. We included 12 Daphnia clones in our study, but clone identity explained only some of the variation in life history traits. We also tested the hypothesis that growth rate would be positively related to intergenic spacer length (i.e. the growth rate hypothesis) across clones, but we found that clones with intermediate intergenic spacer lengths had larger asymptotic sizes and slower growth rates. Our results strongly support a resource-based optimization of body size following the SD model. Furthermore, because some resource allocation decisions necessarily precede others, understanding interdependent life history traits may require a more nested approach.

The rate-size trade-off structures intraspecific variation in Daphnia ambigua life history parameters.

Directory of Open Access Journals (Sweden)

John P DeLong

Full Text Available The identification of trade-offs is necessary for understanding the evolution and maintenance of diversity. Here we employ the supply-demand (SD body size optimization model to predict a trade-off between asymptotic body size and growth rate. We use the SD model to quantitatively predict the slope of the relationship between asymptotic body size and growth rate under high and low food regimes and then test the predictions against observations for Daphnia ambigua. Close quantitative agreement between observed and predicted slopes at both food levels lends support to the model and confirms that a 'rate-size' trade-off structures life history variation in this population. In contrast to classic life history expectations, growth and reproduction were positively correlated after controlling for the rate-size trade-off. We included 12 Daphnia clones in our study, but clone identity explained only some of the variation in life history traits. We also tested the hypothesis that growth rate would be positively related to intergenic spacer length (i.e. the growth rate hypothesis across clones, but we found that clones with intermediate intergenic spacer lengths had larger asymptotic sizes and slower growth rates. Our results strongly support a resource-based optimization of body size following the SD model. Furthermore, because some resource allocation decisions necessarily precede others, understanding interdependent life history traits may require a more nested approach.

Metabolic enzyme cost explains variable trade-offs between microbial growth rate and yield.

Directory of Open Access Journals (Sweden)

Meike T Wortel

2018-02-01

Full Text Available Microbes may maximize the number of daughter cells per time or per amount of nutrients consumed. These two strategies correspond, respectively, to the use of enzyme-efficient or substrate-efficient metabolic pathways. In reality, fast growth is often associated with wasteful, yield-inefficient metabolism, and a general thermodynamic trade-off between growth rate and biomass yield has been proposed to explain this. We studied growth rate/yield trade-offs by using a novel modeling framework, Enzyme-Flux Cost Minimization (EFCM and by assuming that the growth rate depends directly on the enzyme investment per rate of biomass production. In a comprehensive mathematical model of core metabolism in E. coli, we screened all elementary flux modes leading to cell synthesis, characterized them by the growth rates and yields they provide, and studied the shape of the resulting rate/yield Pareto front. By varying the model parameters, we found that the rate/yield trade-off is not universal, but depends on metabolic kinetics and environmental conditions. A prominent trade-off emerges under oxygen-limited growth, where yield-inefficient pathways support a 2-to-3 times higher growth rate than yield-efficient pathways. EFCM can be widely used to predict optimal metabolic states and growth rates under varying nutrient levels, perturbations of enzyme parameters, and single or multiple gene knockouts.

Analysis of the trade-offs between conventional and superconducting interconnections

International Nuclear Information System (INIS)

Frye, R.

1989-01-01

Superconductivity can now be achieved at temperatures compatible with semiconductor device operation. This raises the interesting possibility of using the new, high-temperature superconducting ceramics for interconnections in electronic systems. This paper examines some of the consequences of a resistance-free interconnection medium. A problem with conventional conductors in electronic systems is that the resistance of wires increases quadratically as the wire dimensions are scaled down. Below some minimum cross-sectional area, determined by the metal resistivity and wire length, the resistance in these lines begins to severely limit their bandwidth. Superconductors, on the other hand, are not constrained by the same scaling rules. They provide a high bandwidth interconnection at all sizes and lengths. The limitations for superconductors are set by their critical current densities. If line dimensions become too small, a superconductor will no longer support an adequate flow of current. An analysis is presented examining the performance trade-offs for conventional and superconducting interconnections in applications ranging from printed wiring boards to chips. For most semiconductor device-based applications, the potential gains in wiring density offered by superconductors are probably more important than the bandwidth improvements. An important result of the analysis is that it determines the values of critical current density above which superconductors outperform conventional wires in systems of various physical sizes. This identifies particular interconnection technologies for which high-temperature superconductors show the most promise

An age-structured approach to modelling behavioural variation maintained by life-history trade-offs.

Directory of Open Access Journals (Sweden)

Matthew H T Chan

Full Text Available There have been numerous empirical studies on the fitness consequences of behavioural syndromes in various animal taxa; however, the ecological and evolutionary implications on a population level are still poorly understood. To better understand these implications, we develop a non-linear age-structured mathematical model to qualitatively examine the evolutionary consequences of a heritable boldness personality trait within an animal population. We assume that this heritable boldness trait is positively correlated with boldness towards predators and intraspecific aggressiveness. This assumption leads to a growth/reproductive success versus mortality trade-off, which is thoroughly investigated and documented in the literature. Another life-history trade-off we include in the model is future versus current reproduction, which was shown by Wolf et al. to be a possible mechanism for the evolution of behavioural syndromes within an animal population. The stability of the system is analysed, whereby the characteristic equation is in the form of a homogeneous Fredholm equation of the second kind which depends on both the perturbation and equilibrium solution. The system is found to be stable due to the competition between individuals of similar boldness acting as a negative feedback mechanism. Using numerical simulations we examine the qualitative features of the solution to the system. In particular, we investigate the interplay between the mutation and competition strength between two individuals with different boldness, whereby we find that an increasing competition range acts to push individuals to both extremes of the shy-bold axis, while an increasing mutation range counteracts this effect. This qualitative trait of aggregation of individuals around the shy and bold extremes is also found when examining different birth, mortality and competition functions.

Give 'til it hurts: trade-offs between immunity and male reproductive effort in the decorated cricket, Gryllodes sigillatus.

Science.gov (United States)

Gershman, S N; Barnett, C A; Pettinger, A M; Weddle, C B; Hunt, J; Sakaluk, S K

2010-04-01

Trade-offs between life-history variables can be manifested at either the phenotypic or genetic level, with vastly different evolutionary consequences. Here, we examined whether male decorated crickets (Gryllodes sigillatus) from eight inbred lines and the outbred founder population from which they were derived, trade-off immune effort [lytic activity, phenoloxidase (PO) activity or encapsulation] to produce spermatophylaxes: costly nuptial food gifts essential for successful sperm transfer. Canonical correlation analysis of the outbred population revealed a trade-off between spermatophylax mass and lytic activity. Analysis of our inbred lines, however, revealed that although PO activity, encapsulation, body mass, spermatophylax mass and ampulla (sperm capsule) mass were all highly heritable, lytic activity was not, and there was, therefore, no negative genetic correlation between lytic activity and spermatophylax mass. Thus, males showed a phenotypic but not a genetic trade-off between spermatophylax mass and lytic activity, suggesting that this trade-off is mediated largely by environmental factors.

Selection bias in studies of human reproduction-longevity trade-offs.

Science.gov (United States)

Helle, Samuli

2017-12-13

A shorter lifespan as a potential cost of high reproductive effort in humans has intrigued researchers for more than a century. However, the results have been inconclusive so far and despite strong theoretical expectations we do not currently have compelling evidence for the longevity costs of reproduction. Using Monte Carlo simulation, it is shown here that a common practice in human reproduction-longevity studies using historical data (the most relevant data sources for this question), the omission of women who died prior to menopausal age from the analysis, results in severe underestimation of the potential underlying trade-off between reproduction and lifespan. In other words, assuming that such a trade-off is expressed also during reproductive years, the strength of the trade-off between reproduction and lifespan is progressively weakened when women dying during reproductive ages are sequentially and non-randomly excluded from the analysis. In cases of small sample sizes (e.g. few hundreds of observations), this selection bias by reducing statistical power may even partly explain the null results commonly found in this field. Future studies in this field should thus apply statistical approaches that account for or avoid selection bias in order to recover reliable effect size estimates between reproduction and longevity. © 2017 The Author(s).

Modeling trade-offs between plant fiber and toxins: a framework for quantifying risks perceived by foraging herbivores.

Science.gov (United States)

Camp, Meghan J; Shipley, Lisa A; Johnson, Timothy R; Forbey, Jennifer Sorensen; Rachlow, Janet L; Crowell, Miranda M

2015-12-01

When selecting habitats, herbivores must weigh multiple risks, such as predation, starvation, toxicity, and thermal stress, forcing them to make fitness trade-offs. Here, we applied the method of paired comparisons (PC) to investigate how herbivores make trade-offs between habitat features that influence selection of food patches. The method of PC measures utility and the inverse of utility, relative risk, and makes trade-offs and indifferences explicit by forcing animals to make choices between two patches with different types of risks. Using a series of paired-choice experiments to titrate the equivalence curve and find the marginal rate of substitution for one risk over the other, we evaluated how toxin-tolerant (pygmy rabbit Brachylagus idahoensis) and fiber-tolerant (mountain cottontail rabbit Sylviagus nuttallii) herbivores differed in their hypothesized perceived risk of fiber and toxins in food. Pygmy rabbits were willing to consume nearly five times more of the toxin 1,8-cineole in their diets to avoid consuming higher levels of fiber than were mountain cottontails. Fiber posed a greater relative risk for pygmy rabbits than cottontails and cineole a greater risk for cottontails than pygmy rabbits. Our flexible modeling approach can be used to (1) quantify how animals evaluate and trade off multiple habitat attributes when the benefits and risks are difficult to quantify, and (2) integrate diverse risks that influence fitness and habitat selection into a single index of habitat value. This index potentially could be applied to landscapes to predict habitat selection across several scales.

Finite element modeling of shell shape in the freshwater turtle Pseudemys concinna reveals a trade-off between mechanical strength and hydrodynamic efficiency.

Science.gov (United States)

Rivera, Gabriel; Stayton, C Tristan

2011-10-01

Aquatic species can experience different selective pressures on morphology in different flow regimes. Species inhabiting lotic regimes often adapt to these conditions by evolving low-drag (i.e., streamlined) morphologies that reduce the likelihood of dislodgment or displacement. However, hydrodynamic factors are not the only selective pressures influencing organismal morphology and shapes well suited to flow conditions may compromise performance in other roles. We investigated the possibility of morphological trade-offs in the turtle Pseudemys concinna. Individuals living in lotic environments have flatter, more streamlined shells than those living in lentic environments; however, this flatter shape may also make the shells less capable of resisting predator-induced loads. We tested the idea that "lotic" shell shapes are weaker than "lentic" shell shapes, concomitantly examining effects of sex. Geometric morphometric data were used to transform an existing finite element shell model into a series of models corresponding to the shapes of individual turtles. Models were assigned identical material properties and loaded under identical conditions, and the stresses produced by a series of eight loads were extracted to describe the strength of the shells. "Lotic" shell shapes produced significantly higher stresses than "lentic" shell shapes, indicating that the former is weaker than the latter. Females had significantly stronger shell shapes than males, although these differences were less consistent than differences between flow regimes. We conclude that, despite the potential for many-to-one mapping of shell shape onto strength, P. concinna experiences a trade-off in shell shape between hydrodynamic and mechanical performance. This trade-off may be evident in many other turtle species or any other aquatic species that also depend on a shell for defense. However, evolution of body size may provide an avenue of escape from this trade-off in some cases, as changes in

Environmentally induced development costs underlie fitness tradeoffs.

Science.gov (United States)

Walter, Greg M; Wilkinson, Melanie J; Aguirre, J David; Blows, Mark W; Ortiz-Barrientos, Daniel

2018-06-01

Local adaptation can lead to genotype-by-environment interactions, which can create fitness tradeoffs in alternative environments, and govern the distribution of biodiversity across geographic landscapes. Exploring the ecological circumstances that promote the evolution of fitness tradeoffs requires identifying how natural selection operates and during which ontogenetic stages natural selection is strongest. When organisms disperse to areas outside their natural range, tradeoffs might emerge when organisms struggle to reach key life history stages, or alternatively, die shortly after reaching life history stages if there are greater risks of mortality associated with costs to developing in novel environments. We used multiple populations from four ecotypes of an Australian native wildflower (Senecio pinnatifolius) in reciprocal transplants to explore how fitness tradeoffs arise across ontogeny. We then assessed whether the survival probability for plants from native and foreign populations was contingent on reaching key developmental stages. We found that fitness tradeoffs emerged as ontogeny progressed when native plants were more successful than foreign plants at reaching seedling establishment and maturity. Native and foreign plants that failed to reach seedling establishment died at the same rate, but plants from foreign populations died quicker than native plants after reaching seedling establishment, and died quicker regardless of whether they reached sexual maturity or not. Development rates were similar for native and foreign populations, but changed depending on the environment. Together, our results suggest that natural selection for environment-specific traits early in life history created tradeoffs between contrasting environments. Plants from foreign populations were either unable to develop to seedling establishment, or they suffered increased mortality as a consequence of reaching seedling establishment. The observation of tradeoffs together with

Boldness predicts an individual's position along an exploration-exploitation foraging trade-off.

Science.gov (United States)

Patrick, Samantha C; Pinaud, David; Weimerskirch, Henri

2017-09-01

Individuals do not have complete information about the environment and therefore they face a trade-off between gathering information (exploration) and gathering resources (exploitation). Studies have shown individual differences in components of this trade-off but how stable these strategies are in a population and the intrinsic drivers of these differences is not well understood. Top marine predators are expected to experience a particularly strong trade-off as many species have large foraging ranges and their prey often have a patchy distribution. This environment leads these species to exhibit pronounced exploration and exploitation phases but differences between individuals are poorly resolved. Personality differences are known to be important in foraging behaviour but also in the trade-off between exploration and exploitation. Here we test whether personality predicts an individual exploration-exploitation strategy using wide ranging wandering albatrosses (Diomedea exulans) as a model system. Using GPS tracking data from 276 wandering albatrosses, we extract foraging parameters indicative of exploration (searching) and exploitation (foraging) and show that foraging effort, time in patch and size of patch are strongly correlated, demonstrating these are indicative of an exploration-exploitation (EE) strategy. Furthermore, we show these are consistent within individuals and appear stable in the population, with no reproductive advantage. The searching and foraging behaviour of bolder birds placed them towards the exploration end of the trade-off, whereas shy birds showed greater exploitation. This result provides a mechanism through which individual foraging strategies may emerge. Age and sex affected components of the trade-off, but not the trade-off itself, suggesting these factors may drive behavioural compensation to maintain resource acquisition and this was supported by the evidence that there were no fitness consequence of any EE trait nor the trade-off

Cost, Emissions, and Customer Service Trade-Off Analysis In Pickup and Delivery Systems.

Science.gov (United States)

2011-05-01

This research offers a novel formulation for including emissions into fleet assignment and vehicle routing, and for the : trade-offs faced by fleet operators between cost, emissions, and service quality. This approach enables evaluation of : the impa...

Nuclear energy in Europe: uranium flow modeling and fuel cycle scenario trade-offs from a sustainability perspective.

Science.gov (United States)

Tendall, Danielle M; Binder, Claudia R

2011-03-15

The European nuclear fuel cycle (covering the EU-27, Switzerland and Ukraine) was modeled using material flow analysis (MFA).The analysis was based on publicly available data from nuclear energy agencies and industries, national trade offices, and nongovernmental organizations. Military uranium was not considered due to lack of accessible data. Nuclear fuel cycle scenarios varying spent fuel reprocessing, depleted uranium re-enrichment, enrichment assays, and use of fast neutron reactors, were established. They were then assessed according to environmental, economic and social criteria such as resource depletion, waste production, chemical and radiation emissions, costs, and proliferation risks. The most preferable scenario in the short term is a combination of reduced tails assay and enrichment grade, allowing a 17.9% reduction of uranium demand without significantly increasing environmental, economic, or social risks. In the long term, fast reactors could theoretically achieve a 99.4% decrease in uranium demand and nuclear waste production. However, this involves important costs and proliferation risks. Increasing material efficiency is not systematically correlated with the reduction of other risks. This suggests that an overall optimization of the nuclear fuel cycle is difficult to obtain. Therefore, criteria must be weighted according to stakeholder interests in order to determine the most sustainable solution. This paper models the flows of uranium and associated materials in Europe, and provides a decision support tool for identifying the trade-offs of the alternative nuclear fuel cycles considered.

A sustainability framework for assessing trade-offs in ecosystem services

Directory of Open Access Journals (Sweden)

Jeannine Cavender-Bares

2015-03-01

Full Text Available Achieving sustainability, i.e., meeting the needs of current populations without compromising the needs of future generations, is the major challenge facing global society in the 21st century. Navigating the inherent trade-offs between provisioning, regulating, cultural, and supporting ecosystem services, and doing so in a way that does not compromise natural capital needed to provide services in the future, is critical for sustainable resource management. Here we build upon existing literature, primarily from economics and ecology, to present an analytical framework that integrates (1 the ecological mechanisms that underpin ecosystem services, (2 biophysical trade-offs and inherent limits that constrain management options, (3 preferences and values of stakeholders, and (4 explicit analysis of how systems evolve through time to ensure the goal of meeting the needs of future generations. Well-known ecological models define the relationships and trade-offs among services that represents an "efficiency frontier." Well-known methods in economics that combine preferences that define the willingness of stakeholders to trade off ecosystem services on the efficiency frontiers illuminate desirable outcomes that meet human needs. System dynamics show how the system will evolve with consequent impacts on ecosystem services and human well-being and the effects this has on achieving sustainability. Heterogeneity in biophysical constraints, uncertainty, technological advances, and obstacles imposed by societal factors and governance regimes influence potential and realized ecosystem services. Using a set of contrasting scenarios, we illustrate how progress can be made toward sustainability and the important obstacles that must be addressed in doing so. Our framework for analyzing sustainability drawn from economics and ecology is intended to make an integration of concepts from both disciplines accessible to a wider audience.

A Regional Analysis of the Life Cycle Environmental and Economic Tradeoffs of Different Economic Growth Paths

Directory of Open Access Journals (Sweden)

Weiwei Mo

2018-02-01

Full Text Available Different economic development strategies may result in varied socioeconomic and environmental synergies or tradeoffs, suggesting an opportunity for environmentally conscious planning. To understand such synergies or tradeoffs, a dynamic environmental life cycle assessment was conducted for eleven groups of New Hampshire industries. Historical state level Gross Domestic Product (GDP-by-industry data was combined with economic input-output analysis to calculate the direct and life cycle energy use, freshwater use, greenhouse gas emissions, and eutrophication potential of each industry on a yearly basis for the period of 1997–2012. The future development of agriculture, traditional manufacturing, high tech, and tourism industries were investigated based on government projections. Total life cycle impacts of the 11 industries were found to represent around three to seven times those of direct impacts, indicating the significance of the supply chain impacts. Traditional manufacturing has the highest life cycle impacts even though it contributes to less than 10% of the state GDP. Future development of high tech was found to be the best strategy to increase GDP while imposing the least additional environmental impacts. Tourism presents relatively high impacts in terms of freshwater use and eutrophication potential, and a change in recreational style might be able to reduce its impacts.

Life-history tradeoffs and reproductive cycles in Spotted Owls

Science.gov (United States)

Stoelting, Ricka E.; Gutierrez, R.J.; Kendall, William L.; Peery, M. Zachariah

2015-01-01

The study of tradeoffs among life-history traits has long been key to understanding the evolution of life-history strategies. However, more recently, evolutionary ecologists have realized that reproductive costs have the potential to influence population dynamics. Here, we tested for costs of reproduction in the California Spotted Owl (Strix occidentalis occidentalis), and assessed whether costs of reproduction in year t − 1 on reproduction in year t could be responsible for regionally synchronized biennial cycles in reproductive output. Logistic regression analysis and multistate mark–recapture models with state uncertainty revealed that breeding reduced the likelihood of reproducing in the subsequent year by 16% to 38%, but had no influence on subsequent survival. We also found that costs of reproduction in year t − 1 were correlated with climatic conditions in year t, with evidence of higher costs during the dry phase of the El Niño–Southern Oscillation. Using a simulation-based population model, we showed that strong reproductive costs had the potential to create biennial cycles in population-level reproductive output; however, estimated costs of reproduction appeared to be too small to explain patterns observed in Spotted Owls. In the absence of strong reproductive costs, we hypothesize that observed natural cycles in the reproductive output of Spotted Owls are related to as-yet-unmeasured, regionally concordant fluctuations in environmental conditions or prey resources. Despite theoretical evidence for demographic effects, our analyses illustrate that linking tradeoffs to actual changes in population processes will be challenging because of the potential confounding effects of individual and environmental variation.

Optimizing time and resource allocation trade-offs for investment into morphological and behavioral defense

DEFF Research Database (Denmark)

Steiner, Uli; Pfeiffer, Thomas

2007-01-01

pronounced at intermediate environmental conditions. Optimizing single traits generally leads to a more pronounced response of the defense traits, which implies that studying single traits leads to an overestimation of their response to predation. Behavioral defense and morphological defense compensate......Prey organisms are confronted with time and resource allocation trade-offs. Time allocation trade-offs partition time, for example, between foraging effort to acquire resources and behavioral defense. Resource allocation trade-offs partition the acquired resources between multiple traits...... for and augment each other depending on predator densities and the effectiveness of the defense mechanisms. In the presence of time constraints, the model shows peak investment into morphological and behavioral defense at intermediate resource levels....

Tradeoff analysis for Dependable Real-Time Embedded Systems during the Early Design Phases

DEFF Research Database (Denmark)

Gan, Junhe

Embedded systems are becoming increasingly complex and have tight competing constraints in terms of performance, cost, energy consumption, dependability, flexibility, security, etc. The objective of this thesis is to propose design methods and tools for supporting the tradeoff analysis of competing...... to processing elements, as well as the processor voltage and frequency levels for executing each task, such that transient faults are tolerated, the real-time constraints of the application are satisfied, and the energy consumed is minimized. In this thesis, we target the early design phases, when decisions...... have a high impact on the subsequent implementation choices. However, due to a lack of information, the early design phases are characterized by uncertainties, e.g., in the worst-case execution times (WCETs), in the functionality requirements, or in the hardware component costs. In this context, we...

Exergy analysis of large-scale helium liquefiers: Evaluating design trade-offs

Science.gov (United States)

Thomas, Rijo Jacob; Ghosh, Parthasarathi; Chowdhury, Kanchan

2014-01-01

It is known that higher heat exchanger area, more number of expanders with higher efficiency and more involved configuration with multi-pressure compression system increase the plant efficiency of a helium liquefier. However, they involve higher capital investment and larger size. Using simulation software Aspen Hysys v 7.0 and exergy analysis as the tool of analysis, authors have attempted to identify various trade-offs while selecting the number of stages, the pressure levels in compressor, the cold-end configuration, the heat exchanger surface area, the maximum allowable pressure drop in heat exchangers, the efficiency of expanders, the parallel/series connection of expanders etc. Use of more efficient cold ends reduces the number of refrigeration stages and the size of the plant. For achieving reliability along with performance, a configuration with a combination of expander and Joule-Thomson valve is found to be a better choice for cold end. Use of multi-pressure system is relevant only when the number of refrigeration stages is more than 5. Arrangement of expanders in series reduces the number of expanders as well as the heat exchanger size with slight expense of plant efficiency. Superior heat exchanger (having less pressure drop per unit heat transfer area) results in only 5% increase of plant performance even when it has 100% higher heat exchanger surface area.

Mapping and quantifying ecosystem services: analysis of trade-offs and synergies at the different spatial scales

Science.gov (United States)

Tomczyk, Aleksandra; Ewertowski, Marek

2014-05-01

The importance of conserving the natural environment has been known for a long time. It can be fulfilled by designation of protected areas as well as proper management of broader landscapes. During past two decades, conservation has shifted from a predominantly species- and habitat-focus to a more holistic "ecosystem approach" with an emphasis on "ecosystem services", which underpin the benefits which society can obtain (directly or indirectly) from ecosystems. This study aims to investigate and compare existing land use prioritization models and to develop new GIS-based frameworks for analysis for different spatial scales. Research were carried out in several conservation areas in UK and Poland. Main focus was on regulating (including regulation of soil erosion and landslide susceptibility) and recreation services. A new GIS-based model was developed which enabled to analysis of this services. Different spatial scales, ranging from whole conservation areas to single catchments were chosen for mapping and quantifying. Based on different scenarios three sets of ecosystem services were calculated. Data contained specific land-cover/land-use resulting from the different strategy of the natural conservation for each of the study sites. Modelling was carried out based on the trends identified on the basis of past changes in land-use/land-cover (based on analysis of time-series satellite images), and the probability of a particular class of land-use/land-cover for the chosen scenario. Comparison between results revealed ecosystem service tradeoffs (when the obtaining of one service results in the reducing of another service) and synergies (when multiple services can be provides simultaneously). Results of the study shows where (and under which condition): (1) conservation areas can accommodate more visitors and in the same time provide regulation of soil erosion and protection against landslide developments, (2) further development of recreation services will lead to

A possible tradeoff between developmental rate and pathogen ...

Indian Academy of Sciences (India)

related tradeoffs is that they are mediated via the conflict- ... Keywords. life-history evolution; tradeoff; development time; immune function; pathogen; Drosophila. Journal of Genetics .... This work was supported in parts by funds from Depart-.

Evaluating multiple dimensions of visitors' tradeoffs between access and crowding at Arches National Park using indifference curve analysis

Science.gov (United States)

Steven R. Lawson; Robert E. Manning

2001-01-01

Tradeoffs are an inherent part of many of the decisions faced by outdoor recreation managers. For example, decisions concerning the social carrying capacity of popular attraction sites involve tradeoffs between limiting visitor use to ensure a high quality experience and allowing high levels of visitor use to ensure that large numbers of visitors retain access to park...

Ideology, family policy and gender economic inequality: Different models, different tradeoffs

OpenAIRE

Mandel, Hadas

2007-01-01

This paper focuses on cross-national differences in patterns of gender economic inequality, revealing their affinity to both welfare state policies and prevailing conceptions of gender equality. By mapping multiple aspects of inequality and assembling them into distinctive profiles, the paper shows that each pattern of state intervention is accompanied by an uneven record of achievements and failures in promoting gender equality. These tradeoffs can best be understood by placing them in the i...

Do Managers Face a Performance Trade-off?

DEFF Research Database (Denmark)

Mikkelsen, Maria Falk

2017-01-01

equity, accountability, and procedural justice. However, our knowledge of whether such trade-offs exist is scarce. Using an administrative 10-year panel data set of Danish public schools and principals, this paper analyzes trade-offs between production performance (measured by student performance...... and student pass rate) and process performance (measured by equity, accountability, and procedural justice). Results show no evidence of trade-offs. In contrast, principals who succeed in raising student performance generally also succeed in securing high pass rates, high equity, high accountability, and high...... procedural justice. These results suggest that managers who are able to secure high performance on one dimension of performance will likely also be high performing on other performance dimensions....

Tradeoffs in process strategy games with application in the WDM reconfiguration problem

DEFF Research Database (Denmark)

Cohen, Nathann; Coudert, David; Mazauric, Dorian

2011-01-01

We consider a variant of the graph searching games that models the routing reconfiguration problem in WDM networks. In the digraph processing game, a team of agents aims at processing, or clearing, the vertices of a digraph D. We are interested in two different measures: (1) the total number...... tradeoffs may happen even for a basic class of digraphs. On the other hand, we exhibit classes of graphs for which good tradeoffs can be achieved. We finally detail the relationship between this game and the routing reconfiguration problem. In particular, we prove that any instance of the processing game, i...

Economic opportunities and trade-offs in collaborative forest landscape restoration

Science.gov (United States)

Alan A. Ager; Kevin C. Vogler; Michelle A. Day; John D. Bailey

2017-01-01

We modeled forest restoration scenarios to examine socioeconomic and ecological trade-offs associated with alternative prioritization scenarios. The study examined four US national forests designated as priorities for investments to restore fire resiliency and generate economic opportunities to support local industry. We were particularly interested in economic trade-...

A framework for analyzing the economic tradeoffs between urban commerce and security against terrorism.

Science.gov (United States)

Rose, Adam; Avetisyan, Misak; Chatterjee, Samrat

2014-08-01

This article presents a framework for economic consequence analysis of terrorism countermeasures. It specifies major categories of direct and indirect costs, benefits, spillover effects, and transfer payments that must be estimated in a comprehensive assessment. It develops a spreadsheet tool for data collection, storage, and refinement, as well as estimation of the various components of the necessary economic accounts. It also illustrates the usefulness of the framework in the first assessment of the tradeoffs between enhanced security and changes in commercial activity in an urban area, with explicit attention to the role of spillover effects. The article also contributes a practical user interface to the model for emergency managers. © 2014 Society for Risk Analysis.

Invasion versus isolation: trade-offs in managing native salmonids with barriers to upstream movement.

Science.gov (United States)

Fausch, Kurt D; Rieman, Bruce E; Dunham, Jason B; Young, Michael K; Peterson, Douglas P

2009-08-01

Conservation biologists often face the trade-off that increasing connectivity in fragmented landscapes to reduce extinction risk of native species can foster invasion by non-native species that enter via the corridors created, which can then increase extinction risk. This dilemma is acute for stream fishes, especially native salmonids, because their populations are frequently relegated to fragments of headwater habitat threatened by invasion from downstream by 3 cosmopolitan non-native salmonids. Managers often block these upstream invasions with movement barriers, but isolation of native salmonids in small headwater streams can increase the threat of local extinction. We propose a conceptual framework to address this worldwide problem that focuses on 4 main questions. First, are populations of conservation value present (considering evolutionary legacies, ecological functions, and socioeconomic benefits as distinct values)? Second, are populations vulnerable to invasion and displacement by non-native salmonids? Third, would these populations be threatened with local extinction if isolated with barriers? And, fourth, how should management be prioritized among multiple populations? We also developed a conceptual model of the joint trade-off of invasion and isolation threats that considers the opportunities for managers to make strategic decisions. We illustrated use of this framework in an analysis of the invasion-isolation trade-off for native cutthroat trout (Oncorhynchus clarkii) in 2 contrasting basins in western North America where invasion and isolation are either present and strong or farther away and apparently weak. These cases demonstrate that decisions to install or remove barriers to conserve native salmonids are often complex and depend on conservation values, environmental context (which influences the threat of invasion and isolation), and additional socioeconomic factors. Explicit analysis with tools such as those we propose can help managers make

A population model evaluating the consequences of the evolution of double-resistance and tradeoffs on the benefits of two-drug antibiotic treatments.

Science.gov (United States)

Campbell, Ellsworth M; Chao, Lin

2014-01-01

The evolution of antibiotic resistance in microbes poses one of the greatest challenges to the management of human health. Because addressing the problem experimentally has been difficult, research on strategies to slow the evolution of resistance through the rational use of antibiotics has resorted to mathematical and computational models. However, despite many advances, several questions remain unsettled. Here we present a population model for rational antibiotic usage by adding three key features that have been overlooked: 1) the maximization of the frequency of uninfected patients in the human population rather than the minimization of antibiotic resistance in the bacterial population, 2) the use of cocktails containing antibiotic pairs, and 3) the imposition of tradeoff constraints on bacterial resistance to multiple drugs. Because of tradeoffs, bacterial resistance does not evolve directionally and the system reaches an equilibrium state. When considering the equilibrium frequency of uninfected patients, both cycling and mixing improve upon single-drug treatment strategies. Mixing outperforms optimal cycling regimens. Cocktails further improve upon aforementioned strategies. Moreover, conditions that increase the population frequency of uninfected patients also increase the recovery rate of infected individual patients. Thus, a rational strategy does not necessarily result in a tragedy of the commons because benefits to the individual patient and general public are not in conflict. Our identification of cocktails as the best strategy when tradeoffs between multiple-resistance are operating could also be extended to other host-pathogen systems. Cocktails or other multiple-drug treatments are additionally attractive because they allow re-using antibiotics whose utility has been negated by the evolution of single resistance.

Wideband vs. Multiband Trade-offs for a Scalable Multifunction RF system

NARCIS (Netherlands)

Huizing, A.G.

2005-01-01

This paper presents a concept for a scalable multifunction RF (SMRF) system that allows the RF functionality (radar, electronic warfare and communications) to be easily extended and the RF performance to be scaled to the requirements of different missions and platforms. A trade-off analysis is

Environmental justice research shows the importance of social feedbacks in ecosystem service trade-offs

Directory of Open Access Journals (Sweden)

Neil M. Dawson

2017-09-01

Full Text Available In this article, we shine a spotlight on approaches to research ecosystem service trade-offs and critically assess their representation of relevant social dynamics. Although studies linking ecosystem services and human well-being have provided theoretical insights into social and ecological trade-offs, we argue that ecosystem services research has paid insufficient attention to "social feedbacks," people's cognitive and behavioral responses to change. We demonstrate that augmenting ecosystem services research with environmental justice approaches (exploring perceptions of the distribution of costs and benefits, decision making procedures, and recognition of different values and identities can more effectively capture important responses to ecosystem governance. Spatial analysis of land use change, mixed-method assessment of multidimensional well-being, and qualitative environmental justice research were applied in three villages adjacent to Nam Et-Phou Louey National Protected Area in northern Laos. Spatial analysis showed that, from 2006 to 2015, forest clearance for cultivation remained stable within the protected area. Well-being assessment revealed the local population benefited from rapidly increasing incomes, asset ownership, and reduced poverty during that time. In combination, spatial and well-being analyses paint a picture of limited trade-offs, despite growing incentives to exploit protected land and resources through cash crops and high-value forest products. In contrast, results from environmental justice research revealed profound trade-offs between conservation and local practices, and highlight governance deficiencies relating to procedure and recognition. Consequently, formal protected area rules were perceived to be illegitimate by many and actively undermined, for example through negotiated access with alternative authorities. We conclude that although well-being research provides an essential foundation to understand diverse

Range and Endurance Tradeoffs on Personal Rotorcraft Design

Science.gov (United States)

Snyder, Christopher A.

2016-01-01

Rotorcraft design has always been a challenging tradeoff among overall size, capabilities, complexity, and other factors based on available technology and customer requirements. Advancements in propulsion, energy systems and other technologies have enabled new vehicles and missions; complementary advances in analysis methods and tools enable exploration of these enhanced vehicles and the evolving mission design space. A system study was performed to better understand the interdependency between vehicle design and propulsion system capabilities versus hover / loiter requirements and range capability. Three representative vertical lift vehicles were developed to explore the tradeoff in capability between hover efficiency versus range and endurance capability. The vehicles were a single-main rotor helicopter, a tilt rotor, and a vertical take-off and landing (VTOL) aircraft. Vehicle capability was limited to two or three people (including pilot or crew) and maximum range within one hour of flight (100-200 miles, depending on vehicle). Two types of propulsion and energy storage systems were used in this study. First was traditional hydrocarbon-fueled cycles (such as Otto, diesel or gas turbine cycles). Second was an all-electric system using electric motors, power management and distribution, assuming batteries for energy storage, with the possibility of hydrocarbon-fueled range extenders. The high power requirements for hover significantly reduced mission radius capability. Loiter was less power intensive, resulting in about 1/2 the equivalent mission radius penalty. With so many design variables, the VTOL aircraft has the potential to perform well for a variety of missions. This vehicle is a good candidate for additional study; component model development is also required to adequately assess performance over the design space of interest.

Modeling and analysis of power processing systems: Feasibility investigation and formulation of a methodology

Science.gov (United States)

Biess, J. J.; Yu, Y.; Middlebrook, R. D.; Schoenfeld, A. D.

1974-01-01

A review is given of future power processing systems planned for the next 20 years, and the state-of-the-art of power processing design modeling and analysis techniques used to optimize power processing systems. A methodology of modeling and analysis of power processing equipment and systems has been formulated to fulfill future tradeoff studies and optimization requirements. Computer techniques were applied to simulate power processor performance and to optimize the design of power processing equipment. A program plan to systematically develop and apply the tools for power processing systems modeling and analysis is presented so that meaningful results can be obtained each year to aid the power processing system engineer and power processing equipment circuit designers in their conceptual and detail design and analysis tasks.

An appraisal of the enzyme stability-activity trade-off.

Science.gov (United States)

Miller, Scott R

2017-07-01

A longstanding idea in evolutionary physiology is that an enzyme cannot jointly optimize performance at both high and low temperatures due to a trade-off between stability and activity. Although a stability-activity trade-off has been observed for well-characterized examples, such a trade-off is not imposed by any physical chemical constraint. To better understand the pervasiveness of this trade-off, I investigated the stability-activity relationship for comparative biochemical studies of purified orthologous enzymes identified by a literature search. The nature of this relationship varied greatly among studies. Notably, studies of enzymes with low mean synonymous nucleotide sequence divergence were less likely to exhibit the predicted negative correlation between stability and activity. Similarly, a survey of directed evolution investigations of the stability-activity relationship indicated that these traits are often uncoupled among nearly identical yet phenotypically divergent enzymes. This suggests that the presumptive trade-off often reported for investigations of enzymes with high mean sequence divergence may in some cases instead be a consequence of the degeneration over time of enzyme function in unselected environments, rather than a direct effect of thermal adaptation. The results caution against the general assertion of a stability-activity trade-off during enzyme adaptation. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

Systems thinking, the Swiss Cheese Model and accident analysis: a comparative systemic analysis of the Grayrigg train derailment using the ATSB, AcciMap and STAMP models.

Science.gov (United States)

Underwood, Peter; Waterson, Patrick

2014-07-01

The Swiss Cheese Model (SCM) is the most popular accident causation model and is widely used throughout various industries. A debate exists in the research literature over whether the SCM remains a viable tool for accident analysis. Critics of the model suggest that it provides a sequential, oversimplified view of accidents. Conversely, proponents suggest that it embodies the concepts of systems theory, as per the contemporary systemic analysis techniques. The aim of this paper was to consider whether the SCM can provide a systems thinking approach and remain a viable option for accident analysis. To achieve this, the train derailment at Grayrigg was analysed with an SCM-based model (the ATSB accident investigation model) and two systemic accident analysis methods (AcciMap and STAMP). The analysis outputs and usage of the techniques were compared. The findings of the study showed that each model applied the systems thinking approach. However, the ATSB model and AcciMap graphically presented their findings in a more succinct manner, whereas STAMP more clearly embodied the concepts of systems theory. The study suggests that, whilst the selection of an analysis method is subject to trade-offs that practitioners and researchers must make, the SCM remains a viable model for accident analysis. Copyright © 2013 Elsevier Ltd. All rights reserved.

Trade-offs between forest carbon stocks and harvests in a steady state - A multi-criteria analysis.

Science.gov (United States)

Pingoud, Kim; Ekholm, Tommi; Sievänen, Risto; Huuskonen, Saija; Hynynen, Jari

2018-03-15

This paper provides a perspective for comparing trade-offs between harvested wood flows and forest carbon stocks with different forest management regimes. A constant management regime applied to a forest area with an even age-class distribution leads to a steady state, in which the annual harvest and carbon stocks remain constant over time. As both are desirable - carbon stocks for mitigating climate change and harvests for the economic use of wood and displacing fossil fuels - an ideal strategy should be chosen from a set of management regimes that are Pareto-optimal in the sense of multi-criteria decision-making. When choosing between Pareto-optimal alternatives, the trade-off between carbon stock and harvests is unavoidable. This trade-off can be described e.g. in terms of carbon payback times or carbon returns. As numerical examples, we present steady-state harvest levels and carbon stocks in a Finnish boreal forest region for different rotation periods, thinning intensities and collection patterns for harvest residues. In the set of simulated management practices, harvest residue collection presents the most favorable trade-off with payback times around 30-40 years; while Pareto-optimal changes in rotation or thinnings exhibited payback times over 100 years, or alternatively carbon returns below 1%. By extending the rotation period and using less-intensive thinnings compared to current practices, the steady-state carbon stocks could be increased by half while maintaining current harvest levels. Additional cases with longer rotation periods should be also considered, but were here excluded due to the lack of reliable data on older forest stands. Copyright © 2018 Elsevier Ltd. All rights reserved.

Large-scale bioenergy production: how to resolve sustainability trade-offs?

Science.gov (United States)

Humpenöder, Florian; Popp, Alexander; Bodirsky, Benjamin Leon; Weindl, Isabelle; Biewald, Anne; Lotze-Campen, Hermann; Dietrich, Jan Philipp; Klein, David; Kreidenweis, Ulrich; Müller, Christoph; Rolinski, Susanne; Stevanovic, Miodrag

2018-02-01

Large-scale 2nd generation bioenergy deployment is a key element of 1.5 °C and 2 °C transformation pathways. However, large-scale bioenergy production might have negative sustainability implications and thus may conflict with the Sustainable Development Goal (SDG) agenda. Here, we carry out a multi-criteria sustainability assessment of large-scale bioenergy crop production throughout the 21st century (300 EJ in 2100) using a global land-use model. Our analysis indicates that large-scale bioenergy production without complementary measures results in negative effects on the following sustainability indicators: deforestation, CO2 emissions from land-use change, nitrogen losses, unsustainable water withdrawals and food prices. One of our main findings is that single-sector environmental protection measures next to large-scale bioenergy production are prone to involve trade-offs among these sustainability indicators—at least in the absence of more efficient land or water resource use. For instance, if bioenergy production is accompanied by forest protection, deforestation and associated emissions (SDGs 13 and 15) decline substantially whereas food prices (SDG 2) increase. However, our study also shows that this trade-off strongly depends on the development of future food demand. In contrast to environmental protection measures, we find that agricultural intensification lowers some side-effects of bioenergy production substantially (SDGs 13 and 15) without generating new trade-offs—at least among the sustainability indicators considered here. Moreover, our results indicate that a combination of forest and water protection schemes, improved fertilization efficiency, and agricultural intensification would reduce the side-effects of bioenergy production most comprehensively. However, although our study includes more sustainability indicators than previous studies on bioenergy side-effects, our study represents only a small subset of all indicators relevant for the

Metabolic Trade-offs in Yeast are Caused by F1F0-ATP synthase

DEFF Research Database (Denmark)

Nilsson, Avlant; Nielsen, Jens

2016-01-01

of intermediary metabolism and consequently metabolic trade-offs may take place. One such trade-off, aerobic fermentation, occurs in both yeast (the Crabtree effect) and cancer cells (the Warburg effect) and has been a scientific challenge for decades. Here we show, using flux balance analysis combined...... with in vitro measured enzyme specific activities, that fermentation is more catalytically efficient than respiration, i.e. it produces more ATP per protein mass. And that the switch to fermentation at high growth rates therefore is a consequence of a high ATP production rate, provided by a limited pool...

Exploration of tradeoffs in intensity-modulated radiotherapy

International Nuclear Information System (INIS)

Craft, David; Halabi, Tarek; Bortfeld, Thomas

2005-01-01

The purpose of this study is to calculate Pareto surfaces in multi-criteria radiation treatment planning and to analyse the dependency of the Pareto surfaces on the objective functions used for the volumes of interest. We develop a linear approach that allows us to calculate truly Pareto optimal treatment plans, and we apply it to explore the tradeoff between tumour dose homogeneity and critical structure sparing. We show that for two phantom and two clinical cases, a smooth (as opposed to kinked) Pareto tradeoff curve exists. We find that in the paraspinal cases the Pareto surface is invariant to the response function used on the spinal cord: whether the mean cord dose or the maximum cord dose is used, the Pareto plan database is similar. This is not true for the lung studies, where the choice of objective function on the healthy lung tissue influences the resulting Pareto surface greatly. We conclude that in the special case when the tumour wraps around the organ at risk, e.g. prostate cases and paraspinal cases, the Pareto surface will be largely invariant to the objective function used to model the organ at risk

Trade-off analysis of discharge-desiltation-turbidity and ANN analysis on sedimentation of a combined reservoir-reach system under multi-phase and multi-layer conjunctive releasing operation

Science.gov (United States)

Huang, Chien-Lin; Hsu, Nien-Sheng; Wei, Chih-Chiang; Yao, Chun-Hao

2017-10-01

Multi-objective reservoir operation considering the trade-off of discharge-desiltation-turbidity during typhoons and sediment concentration (SC) simulation modeling are the vital components for sustainable reservoir management. The purposes of this study were (1) to analyze the multi-layer release trade-offs between reservoir desiltation and intake turbidity of downstream purification plants and thus propose a superior conjunctive operation strategy and (2) to develop ANFIS-based (adaptive network-based fuzzy inference system) and RTRLNN-based (real-time recurrent learning neural networks) substitute SC simulation models. To this end, this study proposed a methodology to develop (1) a series of multi-phase and multi-layer sediment-flood conjunctive release modes and (2) a specialized SC numerical model for a combined reservoir-reach system. The conjunctive release modes involve (1) an optimization model where the decision variables are multi-phase reduction/scaling ratios and the timings to generate a superior total release hydrograph for flood control (Phase I: phase prior to flood arrival, Phase II/III: phase prior to/subsequent to peak flow) and (2) a combination method with physical limitations regarding separation of the singular hydrograph into multi-layer release hydrographs for sediment control. This study employed the featured signals obtained from statistical quartiles/sediment duration curve in mesh segmentation, and an iterative optimization model with a sediment unit response matrix and corresponding geophysical-based acceleration factors, for efficient parameter calibration. This research applied the developed methodology to the Shihmen Reservoir basin in Taiwan. The trade-off analytical results using Typhoons Sinlaku and Jangmi as case examples revealed that owing to gravity current and re-suspension effects, Phase I + II can de-silt safely without violating the intake's turbidity limitation before reservoir discharge reaches 2238 m3/s; however

Getting a Cohesive Answer from a Common Start: Scalable Multidisciplinary Analysis through Transformation of a System Model

Science.gov (United States)

Cole, Bjorn; Chung, Seung H.

2012-01-01

One of the challenges of systems engineering is in working multidisciplinary problems in a cohesive manner. When planning analysis of these problems, system engineers must tradeoff time and cost for analysis quality and quantity. The quality is associated with the fidelity of the multidisciplinary models and the quantity is associated with the design space that can be analyzed. The tradeoff is due to the resource intensive process of creating a cohesive multidisciplinary system model and analysis. Furthermore, reuse or extension of the models used in one stage of a product life cycle for another is a major challenge. Recent developments have enabled a much less resource-intensive and more rigorous approach than handwritten translation scripts or codes of multidisciplinary models and their analyses. The key is to work from a core system model defined in a MOF-based language such as SysML and in leveraging the emerging tool ecosystem, such as Query-View- Transform (QVT), from the OMG community. SysML was designed to model multidisciplinary systems and analyses. The QVT standard was designed to transform SysML models. The Europa Hability Mission (EHM) team has begun to exploit these capabilities. In one case, a Matlab/Simulink model is generated on the fly from a system description for power analysis written in SysML. In a more general case, a symbolic mathematical framework (supported by Wolfram Mathematica) is coordinated by data objects transformed from the system model, enabling extremely flexible and powerful tradespace exploration and analytical investigations of expected system performance.

On the cost/delay tradeoff of wireless delay tolerant geographic routing

OpenAIRE

Tasiopoulos, Argyrios; Tsiaras, Christos; Toumpis, Stavros

2012-01-01

In Delay Tolerant Networks (DTNs), there is a fundamental tradeoff between the aggregate transport cost of a packet and the delay in its delivery. We study this tradeoff in the context of geographical routing in wireless DTNs.We ?rst specify the optimal cost/delay tradeoff, i.e., the tradeoff under optimal network operation, using a dynamic network construction termed the Cost/Delay Evolving Graph (C/DEG) and the Optimal Cost/Delay Curve (OC/DC), a function that gives the minimum possible agg...

Privacy and security perceptions of european citizens: A test of the trade-off model

NARCIS (Netherlands)

Friedewald, M.; Lieshout, M. van; Rung, S.; Ooms, M.; Ypma, J.

2015-01-01

This paper considers the relationship between privacy and security and, in particular, the traditional “trade-off” paradigm that argues that citizens might be willing to sacrifice some privacy for more security. Academics have long argued against the trade-off paradigm, but these arguments have

Operational trade-offs in reservoir control

Science.gov (United States)

Georgakakos, Aris P.

1993-11-01

Reservoir operation decisions require constant reevaluation in the face of conflicting objectives, varying hydrologic conditions, and frequent operational policy changes. Optimality is a relative concept very much dependent on the circumstances under which a decision is made. More than anything else, reservoir management authorities need the means to assess the impacts of various operational options. It is their responsibility to define what is desirable after a thorough evaluation of the existing circumstances. This article presents a model designed to generate operational trade-offs common among reservoir systems. The model avoids an all-encompassing problem formulation and distinguishes three operational modes (levels) corresponding to normal, drought, and flood operations. Each level addresses only relevant system elements and uses a static and a dynamic control module to optimize turbine performance within each planning period and temporally. The model is used for planning the operation of the Savannah River System.

Land management influences trade-offs and the total supply of ecosystem services in alpine grassland in Tibet, China.

Science.gov (United States)

Wu, Junxi; Zhao, Yan; Yu, Chengqun; Luo, Liming; Pan, Ying

2017-05-15

Developing sustainable use patterns for alpine grassland in Tibet is the primary challenge related to conserving these vulnerable ecosystems of the 'world's third pole' and guaranteeing the well-being of local inhabitants. This challenge requires researchers to think beyond the methods of most current studies that are limited to a single aspect of conservation or productivity, and focus on balancing various needs. An analysis of trade-offs involving ecosystem services provides a framework that can be used to quantify the type of balancing needed. In this study, we measured variations in four types of ecosystem services under five types of grassland management including grazing exclusion, sowing, combined plowing and grazing exclusion, combined plowing and sowing, and natural grassland, from 2013 to 2015. In addition, we accessed the existence and changing patterns of ecosystem service trade-offs using Spearman coefficients and a trade-off index. The results revealed the existence of trade-offs among provisioning and regulating services. Plowing and sowing could convert the trade-off relationships into synergies immediately. Grazing exclusion reduced the level of trade-offs gradually over time. Thus, the combined plowing and sowing treatment promoted the total supply of multiple ecosystem services when compared with natural grassland. We argue that the variations in dry matter allocation to above- and belowground serve as one cause of the variation in trade-off relationships. Another cause for variation in trade-offs is the varied species competition between selection effects and niche complementarity. Our study provides empirical evidence that the effects of trade-offs among ecosystem services could be reduced and even converted into synergies by optimizing management techniques. Copyright © 2017 Elsevier Ltd. All rights reserved.

Age-dependent trade-offs between immunity and male, but not female, reproduction.

Science.gov (United States)

McNamara, Kathryn B; van Lieshout, Emile; Jones, Therésa M; Simmons, Leigh W

2013-01-01

Immune function is costly and must be traded off against other life-history traits, such as gamete production. Studies of immune trade-offs typically focus on adult individuals, yet the juvenile stage can be a highly protracted period when reproductive resources are acquired and immune challenges are ubiquitous. Trade-offs during development are likely to be important, yet no studies have considered changes in adult responses to immune challenges imposed at different stages of juvenile development. By manipulating the timing of a bacterial immune challenge to the larvae of the cotton bollworm moth, we examined potential trade-offs between investment into immunity at different stages of juvenile development (early or late) and subsequent adult reproductive investment into sperm or egg production. Our data reveal an age-dependent trade-off between juvenile immune function and adult male reproductive investment. Activation of the immune response during late development resulted in a reduced allocation of resources to eupyrene (fertilizing) sperm production. Immune activation from the injection procedure itself (irrespective of whether individuals were injected with an immune elicitor or a control solution) also caused reproductive trade-offs; males injected early in development produced fewer apyrene (nonfertilizing) sperm. Contrary to many other studies, our study demonstrates these immune trade-offs under ad libitum nutritional conditions. No trade-offs were observed between female immune activation and adult reproductive investment. We suggest the differences in trade-offs observed between male sperm types and the absence of reproductive trade-offs in females may be the result of ontogenetic differences in gamete production in this species. Our data reveal developmental windows when trade-offs between immune function and gametic investment are made, and highlight the importance of considering multiple developmental periods when making inferences regarding the

Development of a model for the prediction of the fuel consumption and nitrogen oxides emission trade-off for large ships

DEFF Research Database (Denmark)

Larsen, Ulrik; Pierobon, Leonardo; Baldi, Francesco

2015-01-01

The international regulations on fuel efficiency and NOx emissions of commercial ships motivate the investigation of new system layouts, which can comply with the regulations. In combustion engines, measures to reduce the fuel consumption often lead to increased NOx emissions and careful consider...... that increased system complexity can lead to lower fuel consumption and NOx. Fuel consumption reductions of up to 9% with a 6.5% NOx reduction were achieved using a hybrid turbocharger and organic Rankine cycle waste heat recovery system.......The international regulations on fuel efficiency and NOx emissions of commercial ships motivate the investigation of new system layouts, which can comply with the regulations. In combustion engines, measures to reduce the fuel consumption often lead to increased NOx emissions and careful...... consideration of this trade-off mechanism is required in the design of marine propulsion systems. This study investigates five different configurations of two-stroke diesel-based machinery systems for large ships and their influence on the mentioned trade-off. Numerical models of a low-speed two-stroke diesel...

Global agriculture and carbon trade-offs.

Science.gov (United States)

Johnson, Justin Andrew; Runge, Carlisle Ford; Senauer, Benjamin; Foley, Jonathan; Polasky, Stephen

2014-08-26

Feeding a growing and increasingly affluent world will require expanded agricultural production, which may require converting grasslands and forests into cropland. Such conversions can reduce carbon storage, habitat provision, and other ecosystem services, presenting difficult societal trade-offs. In this paper, we use spatially explicit data on agricultural productivity and carbon storage in a global analysis to find where agricultural extensification should occur to meet growing demand while minimizing carbon emissions from land use change. Selective extensification saves ∼ 6 billion metric tons of carbon compared with a business-as-usual approach, with a value of approximately $1 trillion (2012 US dollars) using recent estimates of the social cost of carbon. This type of spatially explicit geospatial analysis can be expanded to include other ecosystem services and other industries to analyze how to minimize conflicts between economic development and environmental sustainability.

The lack of theoretical support for using person trade-offs in QALY-type models

DEFF Research Database (Denmark)

Østerdal, Lars Peter Raahave

2009-01-01

-adjusted life years (DALYs). This paper discusses the theoretical support for the use of person trade-offs in QALY-type measurement of (changes in) population health. It argues that measures of this type based on such quality-adjustment factors almost always violate the Pareto principle, and so lack normative...

A structured analysis of uncertainty surrounding modeled impacts of groundwater-extraction rules

Science.gov (United States)

Guillaume, Joseph H. A.; Qureshi, M. Ejaz; Jakeman, Anthony J.

2012-08-01

Integrating economic and groundwater models for groundwater-management can help improve understanding of trade-offs involved between conflicting socioeconomic and biophysical objectives. However, there is significant uncertainty in most strategic decision-making situations, including in the models constructed to represent them. If not addressed, this uncertainty may be used to challenge the legitimacy of the models and decisions made using them. In this context, a preliminary uncertainty analysis was conducted of a dynamic coupled economic-groundwater model aimed at assessing groundwater extraction rules. The analysis demonstrates how a variety of uncertainties in such a model can be addressed. A number of methods are used including propagation of scenarios and bounds on parameters, multiple models, block bootstrap time-series sampling and robust linear regression for model calibration. These methods are described within the context of a theoretical uncertainty management framework, using a set of fundamental uncertainty management tasks and an uncertainty typology.

Navigating financial and supply reliability tradeoffs in regional drought management portfolios

Science.gov (United States)

Zeff, Harrison B.; Kasprzyk, Joseph R.; Herman, Jonathan D.; Reed, Patrick M.; Characklis, Gregory W.

2014-06-01

Rising development costs and growing concerns over environmental impacts have led many communities to explore more diversified water management strategies. These "portfolio"-style approaches integrate existing supply infrastructure with other options such as conservation measures or water transfers. Diversified water supply portfolios have been shown to reduce the capacity and costs required to meet demand, while also providing greater adaptability to changing hydrologic conditions. However, this additional flexibility can also cause unexpected reductions in revenue (from conservation) or increased costs (from transfers). The resulting financial instability can act as a substantial disincentive to utilities seeking to implement more innovative water management techniques. This study seeks to design portfolios that employ financial tools (e.g., contingency funds and index insurance) to reduce fluctuations in revenues and costs, allowing these strategies to achieve improved performance without sacrificing financial stability. This analysis is applied to the development of coordinated regional supply portfolios in the "Research Triangle" region of North Carolina, an area comprising four rapidly growing municipalities. The actions of each independent utility become interconnected when shared infrastructure is utilized to enable interutility transfers, requiring the evaluation of regional tradeoffs in up to five performance and financial objectives. Diversified strategies introduce significant tradeoffs between achieving reliability goals and introducing burdensome variability in annual revenues and/or costs. Financial mitigation tools can mitigate the impacts of this variability, allowing for an alternative suite of improved solutions. This analysis provides a general template for utilities seeking to navigate the tradeoffs associated with more flexible, portfolio-style management approaches.

The development of renewable energies and supply security: A trade-off analysis

International Nuclear Information System (INIS)

Röpke, Luise

2013-01-01

This paper analyzes the effects of the green transformation on the German electricity sector with respect to the energy-political triangle. It focuses on how the development of renewable energies will affect security of electricity supply. In a cost–benefit analysis, the value of supply security is compared with its costs of provision. More specifically, the benefits of maintaining the present quality of electricity supply are the avoided social damages from electricity outages and are compared with the respective investment costs in the low- and medium-voltage distribution grid. It is shown that the transformation process towards a green and decentralized production structure will be costly for society, even though the costs can be reduced by different measures. - Highlights: • The effects of the transformation on the German electricity sector are analyzed. • The paper focuses on the trade-off between green energies and supply security. • The benefits of maintaining supply quality are compared with the investment costs. • The costs of maintaining supply quality by far exceed the induced welfare gains. • A strong focus on renewable energies endangers different energy-political goals

Regime switches in the risk-return trade-off

OpenAIRE

Marcellino, Massimiliano; Ghysels, Eric; Guerin, Pierre

2014-01-01

This paper deals with the estimation of the risk-return trade-off. We use a MIDAS model for the conditional variance and allow for possible switches in the risk-return relation through a Markov-switching specification. We find strong evidence for regime changes in the risk-return relation. This finding is robust to a large range of specifications. In the first regime characterized by low ex-post returns and high volatility, the risk-return relation is reversed, whereas the intuitive positive ...

The trade-off between food and temperature in the habitat choice of bluegill sunfish

Science.gov (United States)

Wildhaber, M.L.

2001-01-01

A model is presented to describe the trade-off between food and temperature in bluegills Lepomis macrochirus, where temperature was the primary factor used in determining the patch in which to reside.

Universal Trade-Off between Power, Efficiency, and Constancy in Steady-State Heat Engines

Science.gov (United States)

Pietzonka, Patrick; Seifert, Udo

2018-05-01

Heat engines should ideally have large power output, operate close to Carnot efficiency and show constancy, i.e., exhibit only small fluctuations in this output. For steady-state heat engines, driven by a constant temperature difference between the two heat baths, we prove that out of these three requirements only two are compatible. Constancy enters quantitatively the conventional trade-off between power and efficiency. Thus, we rationalize and unify recent suggestions for overcoming this simple trade-off. Our universal bound is illustrated for a paradigmatic model of a quantum dot solar cell and for a Brownian gyrator delivering mechanical work against an external force.

The Jena Diversity-Dynamic Global Vegetation Model (JeDi-DGVM: a diverse approach to representing terrestrial biogeography and biogeochemistry based on plant functional trade-offs

Directory of Open Access Journals (Sweden)

R. Pavlick

2013-06-01

Full Text Available Terrestrial biosphere models typically abstract the immense diversity of vegetation forms and functioning into a relatively small set of predefined semi-empirical plant functional types (PFTs. There is growing evidence, however, from the field ecology community as well as from modelling studies that current PFT schemes may not adequately represent the observed variations in plant functional traits and their effect on ecosystem functioning. In this paper, we introduce the Jena Diversity-Dynamic Global Vegetation Model (JeDi-DGVM as a new approach to terrestrial biosphere modelling with a richer representation of functional diversity than traditional modelling approaches based on a small number of fixed PFTs. JeDi-DGVM simulates the performance of a large number of randomly generated plant growth strategies, each defined by a set of 15 trait parameters which characterize various aspects of plant functioning including carbon allocation, ecophysiology and phenology. Each trait parameter is involved in one or more functional trade-offs. These trade-offs ultimately determine whether a strategy is able to survive under the climatic conditions in a given model grid cell and its performance relative to the other strategies. The biogeochemical fluxes and land surface properties of the individual strategies are aggregated to the grid-cell scale using a mass-based weighting scheme. We evaluate the simulated global biogeochemical patterns against a variety of field and satellite-based observations following a protocol established by the Carbon-Land Model Intercomparison Project. The land surface fluxes and vegetation structural properties are reasonably well simulated by JeDi-DGVM, and compare favourably with other state-of-the-art global vegetation models. We also evaluate the simulated patterns of functional diversity and the sensitivity of the JeDi-DGVM modelling approach to the number of sampled strategies. Altogether, the results demonstrate the

Payload system tradeoffs for mobile communications satellites

Science.gov (United States)

Moody, H. J.

1990-01-01

System level trade-offs carried out during Mobile Satellite (M-SAT) design activities are described. These trade-offs relate to the use of low level beam forming, flexible power and spectrum distribution, and selection of the number of beams to cover the service area. It is shown that antenna performance can be improved by sharing horns between beams using a low level beam forming network (BFN). Additionally, greatly increased power utilization is possible using a hybrid matrix concept to share power between beams.

Speed-Accuracy Tradeoff in Olfaction

National Research Council Canada - National Science Library

Rinberg, Dmitry; Koulakov, ALexel; Gelperin, Alan

2006-01-01

The basic psychophysical principle of speed-accuracy tradeoff (SAT) has been used to understand key aspects of neuronal information processing in vision and audition, but the principle of SAT is still debated in olfaction...

Developing models that analyze the economic/environmental trade-offs implicit in water resource management

Science.gov (United States)

Howitt, R. E.

2016-12-01

Hydro-economic models have been used to analyze optimal supply management and groundwater use for the past 25 years. They are characterized by an objective function that usually maximizes economic measures such as consumer and producer surplus subject to hydrologic equations of motion or water distribution systems. The hydrologic and economic components are sometimes fully integrated. Alternatively they may use an iterative interactive process. Environmental considerations have been included in hydro-economic models as inequality constraints. Representing environmental requirements as constraints is a rigid approximation of the range of management alternatives that could be used to implement environmental objectives. The next generation of hydro-economic models, currently being developed, require that the environmental alternatives be represented by continuous or semi-continuous functions which relate water resource use allocated to the environment with the probabilities of achieving environmental objectives. These functions will be generated by process models of environmental and biological systems which are now advanced to the state that they can realistically represent environmental systems and flexibility to interact with economic models. Examples are crop growth models, climate modeling, and biological models of forest, fish, and fauna systems. These process models can represent environmental outcomes in a form that is similar to economic production functions. When combined with economic models the interacting process models can reproduce a range of trade-offs between economic and environmental objectives, and thus optimize social value of many water and environmental resources. Some examples of this next-generation of hydro-enviro- economic models are reviewed. In these models implicit production functions for environmental goods are combined with hydrologic equations of motion and economic response functions. We discuss models that show interaction between

Temporal trade-offs in psychophysics.

Science.gov (United States)

Barack, David L; Gold, Joshua I

2016-04-01

Psychophysical techniques typically assume straightforward relationships between manipulations of real-world events, their effects on the brain, and behavioral reports of those effects. However, these relationships can be influenced by many complex, strategic factors that contribute to task performance. Here we discuss several of these factors that share two key features. First, they involve subjects making flexible use of time to process information. Second, this flexibility can reflect the rational regulation of information-processing trade-offs that can play prominent roles in particular temporal epochs: sensitivity to stability versus change for past information, speed versus accuracy for current information, and exploitation versus exploration for future goals. Understanding how subjects manage these trade-offs can be used to help design and interpret psychophysical studies. Copyright © 2016 Elsevier Ltd. All rights reserved.

Life history trade-offs imposed by dragline use in two money spiders.

Science.gov (United States)

Bonte, Dries; Verduyn, Lieselot; Braeckman, Bart P

2016-01-01

Trade-offs among life history traits are central to understanding the limits of adaptations to stress. In animals, virtually all decisions taken during life are expected to have downstream consequences. To what degree rare, but energy-demanding, decisions carry over to individual performance is rarely studied in arthropods. We used spiders as a model system to test how single investments in silk use - for dispersal or predator escape - affect individual performance. Silk produced for safe lines and as threads for ballooning is of the strongest kind and is energetically costly, especially when resources are limited. We induced dragline spinning in two species of money spider at similar quantities to that under natural conditions and tested trade-offs with lifespan and egg sac production under unlimited prey availability and a dietary restriction treatment. We demonstrate strong trade-offs between dragline spinning and survival and fecundity. Survival trade-offs were additive to those imposed by the dietary treatment, but a reduction in eggs produced after silk use was only prevalent under conditions where food was restricted during the spider's life. Because draglines are not recycled after their use for dispersal or predator escape, their spinning incurs substantial fitness costs in dispersal, especially in environments with prey limitation. Rare but energetically costly decisions related to dispersal or predator escape may thus carry over to adult performance and explain phenotypic heterogeneity in natural populations. © 2016. Published by The Company of Biologists Ltd.

The evolution of trade-offs under directional and correlational selection.

Science.gov (United States)

Roff, Derek A; Fairbairn, Daphne J

2012-08-01

Using quantitative genetic theory, we develop predictions for the evolution of trade-offs in response to directional and correlational selection. We predict that directional selection favoring an increase in one trait in a trade-off will result in change in the intercept but not the slope of the trade-off function, with the mean value of the selected trait increasing and that of the correlated trait decreasing. Natural selection will generally favor an increase in some combination of trait values, which can be represented as directional selection on an index value. Such selection induces both directional and correlational selection on the component traits. Theory predicts that selection on an index value will also change the intercept but not the slope of the trade-off function but because of correlational selection, the direction of change in component traits may be in the same or opposite directions. We test these predictions using artificial selection on the well-established trade-off between fecundity and flight capability in the cricket, Gryllus firmus and compare the empirical results with a priori predictions made using genetic parameters from a separate half-sibling experiment. Our results support the predictions and illustrate the complexity of trade-off evolution when component traits are subject to both directional and correlational selection. © 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.

Evolutionary tradeoffs, Pareto optimality and the morphology of ammonite shells.

Science.gov (United States)

Tendler, Avichai; Mayo, Avraham; Alon, Uri

2015-03-07

Organisms that need to perform multiple tasks face a fundamental tradeoff: no design can be optimal at all tasks at once. Recent theory based on Pareto optimality showed that such tradeoffs lead to a highly defined range of phenotypes, which lie in low-dimensional polyhedra in the space of traits. The vertices of these polyhedra are called archetypes- the phenotypes that are optimal at a single task. To rigorously test this theory requires measurements of thousands of species over hundreds of millions of years of evolution. Ammonoid fossil shells provide an excellent model system for this purpose. Ammonoids have a well-defined geometry that can be parameterized using three dimensionless features of their logarithmic-spiral-shaped shells. Their evolutionary history includes repeated mass extinctions. We find that ammonoids fill out a pyramid in morphospace, suggesting five specific tasks - one for each vertex of the pyramid. After mass extinctions, surviving species evolve to refill essentially the same pyramid, suggesting that the tasks are unchanging. We infer putative tasks for each archetype, related to economy of shell material, rapid shell growth, hydrodynamics and compactness. These results support Pareto optimality theory as an approach to study evolutionary tradeoffs, and demonstrate how this approach can be used to infer the putative tasks that may shape the natural selection of phenotypes.

Balancing ecosystem services with energy and food security - Assessing trade-offs from reservoir operation and irrigation investments in Kenya's Tana Basin

Science.gov (United States)

Hurford, A. P.; Harou, J. J.

2014-08-01

Competition for water between key economic sectors and the environment means agreeing allocations is challenging. Managing releases from the three major dams in Kenya's Tana River basin with its 4.4 million inhabitants, 567 MW of installed hydropower capacity, 33 000 ha of irrigation and ecologically important wetlands and forests is a pertinent example. This research seeks firstly to identify and help decision-makers visualise reservoir management strategies which result in the best possible (Pareto-optimal) allocation of benefits between sectors. Secondly, it seeks to show how trade-offs between achievable benefits shift with the implementation of proposed new rice, cotton and biofuel irrigation projects. To approximate the Pareto-optimal trade-offs we link a water resources management simulation model to a multi-criteria search algorithm. The decisions or "levers" of the management problem are volume-dependent release rules for the three major dams and extent of investment in new irrigation schemes. These decisions are optimised for eight objectives covering the provision of water supply and irrigation, energy generation and maintenance of ecosystem services. Trade-off plots allow decision-makers to assess multi-reservoir rule-sets and irrigation investment options by visualising their impacts on different beneficiaries. Results quantify how economic gains from proposed irrigation schemes trade-off against the disturbance of ecosystems and local livelihoods that depend on them. Full implementation of the proposed schemes is shown to come at a high environmental and social cost. The clarity and comprehensiveness of "best-case" trade-off analysis is a useful vantage point from which to tackle the interdependence and complexity of "water-energy-food nexus" resource security issues.

Reproductive tradeoffs and yolk steroids in female leopard geckos, Eublepharis macularius.

Science.gov (United States)

Rhen, T; Crews, D; Fivizzani, A; Elf, P

2006-11-01

Life history theory predicts tradeoffs among reproductive traits, but the physiological mechanisms underlying such tradeoffs remain unclear. Here we examine reproductive tradeoffs and their association with yolk steroids in an oviparous lizard. Female leopard geckos lay two eggs in a clutch, produce multiple clutches in a breeding season, and reproduce for several years. We detected a significant tradeoff between egg size and the number of clutches laid by females during their first two breeding seasons. Total reproductive effort was strongly condition-dependent in the first season, but much less so in the second season. Although these and other tradeoffs were unmistakable, they were not associated with levels of androstenedione, oestradiol, or testosterone in egg yolk. Female condition and egg size, however, were inversely related to dihydrotestosterone (DHT) levels in egg yolk. Finally, steroid levels in egg yolk were not directly related to steroid levels in the maternal circulation when follicles were developing, indicating that steroid transfer to eggs is regulated. These findings suggest that maternal allocation of DHT could mitigate tradeoffs that lead to poor offspring quality (i.e. poor female condition) and small offspring size (i.e. small egg size).

Publish or patent: bibliometric evidence for empirical trade-offs in national funding strategies

NARCIS (Netherlands)

Shelton, R.D.; Leydesdorff, L.

2012-01-01

Multivariate linear regression models suggest a trade-off in allocations of national research and development (R&D). Government funding and spending in the higher education sector encourage publications as a long-term research benefit. Conversely, other components such as industrial funding and

Session 6: Dynamic Modeling and Systems Analysis

Science.gov (United States)

Csank, Jeffrey; Chapman, Jeffryes; May, Ryan

2013-01-01

These presentations cover some of the ongoing work in dynamic modeling and dynamic systems analysis. The first presentation discusses dynamic systems analysis and how to integrate dynamic performance information into the systems analysis. The ability to evaluate the dynamic performance of an engine design may allow tradeoffs between the dynamic performance and operability of a design resulting in a more efficient engine design. The second presentation discusses the Toolbox for Modeling and Analysis of Thermodynamic Systems (T-MATS). T-MATS is a Simulation system with a library containing the basic building blocks that can be used to create dynamic Thermodynamic Systems. Some of the key features include Turbo machinery components, such as turbines, compressors, etc., and basic control system blocks. T-MAT is written in the Matlab-Simulink environment and is open source software. The third presentation focuses on getting additional performance from the engine by allowing the limit regulators only to be active when a limit is danger of being violated. Typical aircraft engine control architecture is based on MINMAX scheme, which is designed to keep engine operating within prescribed mechanical/operational safety limits. Using a conditionally active min-max limit regulator scheme, additional performance can be gained by disabling non-relevant limit regulators

Sustainability Orientation and Entrepreneurship Orientation: Is There a Tradeoff Relationship between Them?

Directory of Open Access Journals (Sweden)

Chang Soo Sung

2018-02-01

Full Text Available Sustainability and entrepreneurship are often regarded as binary concepts that have a tradeoff relationship, meaning that the higher the social and environmental consideration, the lower the private and economic benefits. The purpose of this study is to investigate the effect of individual sustainability orientation on opportunity recognition and sustainable entrepreneurship intention, and examine whether it has a tradeoff relationship with entrepreneurship orientation. The result of this study shows that sustainability orientation has a positive relationship with opportunity recognition and entrepreneurship intention related to sustainability. Analysis of the moderating effects of entrepreneurship orientation reveals the positive effect with sustainability orientation but negative effect with opportunity recognition on sustainable entrepreneurship intention. This study would suggest implications to entrepreneurs on how to balance sustainability and entrepreneurship and promote sustainability entrepreneurship.

An Adaptive Tradeoff Algorithm for Multi-issue SLA Negotiation

Science.gov (United States)

Son, Seokho; Sim, Kwang Mong

Since participants in a Cloud may be independent bodies, mechanisms are necessary for resolving different preferences in leasing Cloud services. Whereas there are currently mechanisms that support service-level agreement negotiation, there is little or no negotiation support for concurrent price and timeslot for Cloud service reservations. For the concurrent price and timeslot negotiation, a tradeoff algorithm to generate and evaluate a proposal which consists of price and timeslot proposal is necessary. The contribution of this work is thus to design an adaptive tradeoff algorithm for multi-issue negotiation mechanism. The tradeoff algorithm referred to as "adaptive burst mode" is especially designed to increase negotiation speed and total utility and to reduce computational load by adaptively generating concurrent set of proposals. The empirical results obtained from simulations carried out using a testbed suggest that due to the concurrent price and timeslot negotiation mechanism with adaptive tradeoff algorithm: 1) both agents achieve the best performance in terms of negotiation speed and utility; 2) the number of evaluations of each proposal is comparatively lower than previous scheme (burst-N).

Convection shapes the trade-off between antibiotic efficacy and the selection for resistance in spatial gradients

Science.gov (United States)

Gralka, Matti; Fusco, Diana; Martis, Stephen; Hallatschek, Oskar

2017-08-01

Since penicillin was discovered about 90 years ago, we have become used to using drugs to eradicate unwanted pathogenic cells. However, using drugs to kill bacteria, viruses or cancer cells has the serious side effect of selecting for mutant types that survive the drug attack. A crucial question therefore is how one could eradicate as many cells as possible for a given acceptable risk of drug resistance evolution. We address this general question in a model of drug resistance evolution in spatial drug gradients, which recent experiments and theories have suggested as key drivers of drug resistance. Importantly, our model takes into account the influence of convection, resulting for instance from blood flow. Using stochastic simulations, we study the fates of individual resistance mutations and quantify the trade-off between the killing of wild-type cells and the rise of resistance mutations: shallow gradients and convection into the antibiotic region promote wild-type death, at the cost of increasing the establishment probability of resistance mutations. We can explain these observed trends by modeling the adaptation process as a branching random walk. Our analysis reveals that the trade-off between death and adaptation depends on the relative length scales of the spatial drug gradient and random dispersal, and the strength of convection. Our results show that convection can have a momentous effect on the rate of establishment of new mutations, and may heavily impact the efficiency of antibiotic treatment.

Contract Source Selection: An Analysis of Lowest Price Technically Acceptable and Tradeoff Strategies

Science.gov (United States)

2016-06-01

it can start moderately, and as it progresses to the right, price is seen to be less important than the advantage (non-cost factor) gained. 3... advantages compared to the LPTA source selection strategy. These include “learning,” “ business judgment,” “flexibility,” and “customer satisfaction...2014, p. 5). The next advantage is the use of business judgment. The tradeoff source selection strategy is highly subjective and this allows the source

Reassessing the Trade-off Hypothesis

DEFF Research Database (Denmark)

Rosas, Guillermo; Manzetti, Luigi

2015-01-01

Do economic conditions drive voters to punish politicians that tolerate corruption? Previous scholarly work contends that citizens in young democracies support corrupt governments that are capable of promoting good economic outcomes, the so-called trade-off hypothesis. We test this hypothesis based...

Trade-offs in ecosystem services and varying stakeholder preferences: evaluating conflicts, obstacles, and opportunities

Directory of Open Access Journals (Sweden)

Elizabeth King

2015-09-01

Full Text Available In efforts to increase human well-being while maintaining the natural systems and processes upon which we depend, navigating the trade-offs that can arise between different ecosystem services is a profound challenge. We evaluated a recently developed simple analytic framework for assessing ecosystem service trade-offs, which characterizes such trade-offs in terms of their underlying biophysical constraints as well as divergences in stakeholders' values for the services in question. Through a workshop and subsequent discussions, we identified four different types of challenging situations under which the framework allows important insights to clarify the nature of stakeholder conflicts, obstacles to promoting more sustainable outcomes, and potential enabling factors to promote efficiency and sustainability of ecosystem service yields. We illustrated the framework's analytical steps by applying them to case studies representing three of the challenging situations. We explored the fourth challenging situation conceptually, using published literature for examples. We examined the potential utility and feasibility of using the framework as a participatory tool in resource management and conflict resolution. We concluded that the framework can be instrumental for promoting pluralism and insightful analysis of trade-offs. The insights offered here may be viewed as hypotheses to be tested and refined as additional unforeseen challenges and benefits are revealed as the framework is put into practice.

The hyperspectral imaging trade-off

DEFF Research Database (Denmark)

Carstensen, Jens Michael

, this will be the standard situation, and it enables the detection of small spectral features like peaks, valleys and shoulders for a wide range of chemistries. Everything else being equal this is what you would wish for, and hyperspectral imaging is often used in research and in remote sensing because of the needs and cost......Although it has no clear-cut definition, hyperspectral imaging in the UV-Visible-NIR wavelength region seems to mean spectral image sampling in bands from 10 nm width or narrower that enables spectral reconstruction over some wavelength interval. For non-imaging spectral applications...... structures in these projects. However, hyperspectral imaging is a sampling choice within spectral imaging that typically will impose some trade-offs, and these trade-offs will not be optimal for many applications. The purpose of this presentation is to point out and increase the awareness of these trade...

Trade-off Analysis of Virtual Inertia and Fast Primary Frequency Control During Frequency Transients in a Converter Dominated Network

DEFF Research Database (Denmark)

Rezkalla, Michel M.N.; Marinelli, Mattia; Pertl, Michael

2016-01-01

Traditionally the electricity generation is based on rotating synchronous machines which provide inertia to the power system.The increasing share of converter connected energy sources reduces the available rotational inertia in the power system leading to faster frequency dynamics, which may cause...... more critical frequency excursions. Both, virtual inertia and fast primary control could serve as a solution to improvefrequency stability, however, their respective impacts on the system have different consequences, so that the trade-off is not straightforward. This study presents a comparative...... analysis of virtual inertiaand a fast primary control algorithms with respect to rate of change of frequency (ROCOF), frequency nadir and steady state value considering the effect of the dead time which is carried out by a sensitivity analysis. The investigation shows that the virtual inertia controller...

Information-disturbance tradeoff in estimating a unitary transformation

International Nuclear Information System (INIS)

Bisio, Alessandro; D'Ariano, Giacomo Mauro; Perinotti, Paolo; Chiribella, Giulio

2010-01-01

We address the problem of the information-disturbance tradeoff associated to the estimation of a quantum transformation and show how the extraction of information about a black box causes a perturbation of the corresponding input-output evolution. In the case of a black box performing a unitary transformation, randomly distributed according to the invariant measure, we give a complete solution of the problem, deriving the optimal tradeoff curve and presenting an explicit construction of the optimal quantum network.

Choosing wisely: a model-based analysis evaluating the trade-offs in cancer benefit and diagnostic referrals among alternative HPV testing strategies in Norway.

Science.gov (United States)

Burger, Emily A; Pedersen, Kine; Sy, Stephen; Kristiansen, Ivar Sønbø; Kim, Jane J

2017-09-05

Forthcoming cervical cancer screening strategies involving human papillomavirus (HPV) testing for women not vaccinated against HPV infections may increase colposcopy referral rates. We quantified health and resource trade-offs associated with alternative HPV-based algorithms to inform decision-makers when choosing between candidate algorithms. We used a mathematical simulation model of HPV-induced cervical carcinogenesis in Norway. We compared the current cytology-based strategy to alternative strategies that varied by the switching age to primary HPV testing (ages 25-34 years), the routine screening frequency (every 3-10 years), and management of HPV-positive, cytology-negative women. Model outcomes included reductions in lifetime cervical cancer risk, relative colposcopy rates, and colposcopy rates per cervical cancer prevented. The age of switching to primary HPV testing and the screening frequency had the largest impacts on cancer risk reductions, which ranged from 90.9% to 96.3% compared to no screening. In contrast, increasing the follow-up intensity of HPV-positive, cytology-negative women provided only minor improvements in cancer benefits, but generally required considerably higher rates of colposcopy referrals compared to current levels, resulting in less efficient cervical cancer prevention. We found that in order to maximise cancer benefits HPV-based screening among unvaccinated women should not be delayed: rather, policy makers should utilise the triage mechanism to control colposcopy referrals.

The offspring quantity–quality trade-off and human fertility variation

Science.gov (United States)

Lawson, David W.; Borgerhoff Mulder, Monique

2016-01-01

The idea that trade-offs between offspring quantity and quality shape reproductive behaviour has long been central to economic perspectives on fertility. It also has a parallel and richer theoretical foundation in evolutionary ecology. We review the application of the quantity–quality trade-off concept to human reproduction, emphasizing distinctions between clutch size and lifetime fertility, and the wider set of forces contributing to fertility variation in iteroparous and sexually reproducing species like our own. We then argue that in settings approximating human evolutionary history, several factors limit costly sibling competition. Consequently, while the optimization of quantity–quality trade-offs undoubtedly shaped the evolution of human physiology setting the upper limits of reproduction, we argue it plays a modest role in accounting for socio-ecological and individual variation in fertility. Only upon entering the demographic transition can fertility limitation be clearly interpreted as strategically orientated to advancing offspring quality via increased parental investment per child, with low fertility increasing descendant socio-economic success, although not reproductive success. We conclude that existing economic and evolutionary literature has often overemphasized the centrality of quantity–quality trade-offs to human fertility variation and advocate for the development of more holistic frameworks encompassing alternative life-history trade-offs and the evolved mechanisms guiding their resolution. PMID:27022072

Ecosystem service trade-offs and synergies misunderstood without landscape history

Directory of Open Access Journals (Sweden)

Stephanie A. Tomscha

2016-03-01

Full Text Available Dramatic changes in ecosystem services have motivated recent work characterizing their interactions, including identifying trade-offs and synergies. Although time is arguably implicit in these ideas of trade-offs and synergies (e.g., temporal dynamics or changes in ecosystem services, such interactions are routinely inferred based on the spatial relationships among ecosystem services alone (e.g., spatial concordance of ecosystem services indicates synergies, whereas incongruence signifies trade-offs. The limitations of this approach have not been fully explored. We quantified ecosystem service interactions using correlations among contemporary ecosystem services and compared these results to those derived by incorporating change in ecosystem services from an earlier decade. To document change over ~60 years in an urbanizing floodplain, we used aerial photography to map multiple floodplain-associated ecosystem services. Our results demonstrate how incorporating landscape baselines can influence measured synergies and trade-offs. Spatial correlations among contemporary ecosystem services missed several interactions that were detected when using prior baseline ecosystem services. Ignoring the history of ecosystem services and their change over time may result in missed opportunities to foster their synergies and lead to unnecessary trade-offs. Efforts to incorporate ecosystem services into land management should include long-term monitoring and baseline reconstructions of ecosystem services.

Efficient surrogate models for reliability analysis of systems with multiple failure modes

International Nuclear Information System (INIS)

Bichon, Barron J.; McFarland, John M.; Mahadevan, Sankaran

2011-01-01

Despite many advances in the field of computational reliability analysis, the efficient estimation of the reliability of a system with multiple failure modes remains a persistent challenge. Various sampling and analytical methods are available, but they typically require accepting a tradeoff between accuracy and computational efficiency. In this work, a surrogate-based approach is presented that simultaneously addresses the issues of accuracy, efficiency, and unimportant failure modes. The method is based on the creation of Gaussian process surrogate models that are required to be locally accurate only in the regions of the component limit states that contribute to system failure. This approach to constructing surrogate models is demonstrated to be both an efficient and accurate method for system-level reliability analysis. - Highlights: → Extends efficient global reliability analysis to systems with multiple failure modes. → Constructs locally accurate Gaussian process models of each response. → Highly efficient and accurate method for assessing system reliability. → Effectiveness is demonstrated on several test problems from the literature.

Local Orientation and the Evolution of Foraging: Changes in Decision Making Can Eliminate Evolutionary Trade-offs

Science.gov (United States)

van der Post, Daniel J.; Semmann, Dirk

2011-01-01

Information processing is a major aspect of the evolution of animal behavior. In foraging, responsiveness to local feeding opportunities can generate patterns of behavior which reflect or “recognize patterns” in the environment beyond the perception of individuals. Theory on the evolution of behavior generally neglects such opportunity-based adaptation. Using a spatial individual-based model we study the role of opportunity-based adaptation in the evolution of foraging, and how it depends on local decision making. We compare two model variants which differ in the individual decision making that can evolve (restricted and extended model), and study the evolution of simple foraging behavior in environments where food is distributed either uniformly or in patches. We find that opportunity-based adaptation and the pattern recognition it generates, plays an important role in foraging success, particularly in patchy environments where one of the main challenges is “staying in patches”. In the restricted model this is achieved by genetic adaptation of move and search behavior, in light of a trade-off on within- and between-patch behavior. In the extended model this trade-off does not arise because decision making capabilities allow for differentiated behavioral patterns. As a consequence, it becomes possible for properties of movement to be specialized for detection of patches with more food, a larger scale information processing not present in the restricted model. Our results show that changes in decision making abilities can alter what kinds of pattern recognition are possible, eliminate an evolutionary trade-off and change the adaptive landscape. PMID:21998571

On the Verge: Costs and Tradeoffs Facing Community College Students

Science.gov (United States)

Cochrane, Debbie; Szabo-Kubitz, Laura

2016-01-01

"On the Verge: Costs and Tradeoffs Facing Community College Students" documents California community college students' struggles to cover college expenses beyond tuition, their experiences with financial aid, and the troubling tradeoffs they face when available resources do not stretch far enough. Consistent with a growing body of…

On minimizing assignment errors and the trade-off between false positives and negatives in parentage analysis

KAUST Repository

Harrison, Hugo B.

2013-11-04

Genetic parentage analyses provide a practical means with which to identify parent-offspring relationships in the wild. In Harrison et al.\\'s study (2013a), we compare three methods of parentage analysis and showed that the number and diversity of microsatellite loci were the most important factors defining the accuracy of assignments. Our simulations revealed that an exclusion-Bayes theorem method was more susceptible to false-positive and false-negative assignments than other methods tested. Here, we analyse and discuss the trade-off between type I and type II errors in parentage analyses. We show that controlling for false-positive assignments, without reporting type II errors, can be misleading. Our findings illustrate the need to estimate and report both the rate of false-positive and false-negative assignments in parentage analyses. © 2013 John Wiley & Sons Ltd.

On minimizing assignment errors and the trade-off between false positives and negatives in parentage analysis

KAUST Repository

Harrison, Hugo B.; Saenz Agudelo, Pablo; Planes, Serge; Jones, Geoffrey P.; Berumen, Michael L.

2013-01-01

Genetic parentage analyses provide a practical means with which to identify parent-offspring relationships in the wild. In Harrison et al.'s study (2013a), we compare three methods of parentage analysis and showed that the number and diversity of microsatellite loci were the most important factors defining the accuracy of assignments. Our simulations revealed that an exclusion-Bayes theorem method was more susceptible to false-positive and false-negative assignments than other methods tested. Here, we analyse and discuss the trade-off between type I and type II errors in parentage analyses. We show that controlling for false-positive assignments, without reporting type II errors, can be misleading. Our findings illustrate the need to estimate and report both the rate of false-positive and false-negative assignments in parentage analyses. © 2013 John Wiley & Sons Ltd.

Trade-offs between driving nodes and time-to-control in complex networks

Science.gov (United States)

Pequito, Sérgio; Preciado, Victor M.; Barabási, Albert-László; Pappas, George J.

2017-01-01

Recent advances in control theory provide us with efficient tools to determine the minimum number of driving (or driven) nodes to steer a complex network towards a desired state. Furthermore, we often need to do it within a given time window, so it is of practical importance to understand the trade-offs between the minimum number of driving/driven nodes and the minimum time required to reach a desired state. Therefore, we introduce the notion of actuation spectrum to capture such trade-offs, which we used to find that in many complex networks only a small fraction of driving (or driven) nodes is required to steer the network to a desired state within a relatively small time window. Furthermore, our empirical studies reveal that, even though synthetic network models are designed to present structural properties similar to those observed in real networks, their actuation spectra can be dramatically different. Thus, it supports the need to develop new synthetic network models able to replicate controllability properties of real-world networks.

Economics of social trade-off: Balancing wastewater treatment cost and ecosystem damage.

Science.gov (United States)

Jiang, Yu; Dinar, Ariel; Hellegers, Petra

2018-04-01

We have developed a social optimization model that integrates the financial and ecological costs associated with wastewater treatment and ecosystem damage. The social optimal abatement level of water pollution is determined by finding the trade-off between the cost of pollution control and its resulting ecosystem damage. The model is applied to data from the Lake Taihu region in China to demonstrate this trade-off. A wastewater treatment cost function is estimated with a sizable sample from China, and an ecological damage cost function is estimated following an ecosystem service valuation framework. Results show that the wastewater treatment cost function has economies of scale in facility capacity, and diseconomies in pollutant removal efficiency. Results also show that a low value of the ecosystem service will lead to serious ecological damage. One important policy implication is that the assimilative capacity of the lake should be enhanced by forbidding over extraction of water from the lake. It is also suggested that more work should be done to improve the accuracy of the economic valuation. Copyright © 2018 Elsevier Ltd. All rights reserved.

Managing unforeseen events in anesthesia: collective trade-off between "understanding" and "doing".

Science.gov (United States)

Cuvelier, L; Falzon, P; Granry, J C; Moll, M C

2012-01-01

This study aims to describe how anesthesia teams handle unforeseen events that may affect the patients' health. More precisely, it investigates the mechanisms of decisions made by anesthesia teams to manage unthought-of situations, i.e. situations that have not been foreseen as "possible" ones before their occurrence. An empirical study, based on the analysis of simulated situations, was conducted in a pediatric anesthesia service of a university hospital in France. The results highlighted three ways of managing unthought-of situations (determined management, cautious management and overwhelmed management). They support the hypothesis of a collective cognitive trade-off, whereby teams would behave as virtual operators, with their own collective trade-off between "understanding" and "doing". The discussion of the results questions the assessment criteria, the safety perspectives we adopt and the possible ways to improve the management of unforeseen situations.

Rate-cost tradeoffs in control

KAUST Repository

Kostina, Victoria; Hassibi, Babak

2017-01-01

function is the mean-square deviation of the system state from the desired state. We study the fundamental tradeoff between the communication rate r bits/sec and the limsup of the expected cost b, and show a lower bound on the rate necessary to attain b

WE-AB-209-02: A New Inverse Planning Framework with Principle-Based Modeling of Inter-Structural Dosimetric Tradeoffs

International Nuclear Information System (INIS)

Liu, H; Dong, P; Xing, L

2016-01-01

Purpose: Traditional radiotherapy inverse planning relies on the weighting factors to phenomenologically balance the conflicting criteria for different structures. The resulting manual trial-and-error determination of the weights has long been recognized as the most time-consuming part of treatment planning. The purpose of this work is to develop an inverse planning framework that parameterizes the inter-structural dosimetric tradeoff among with physically more meaningful quantities to simplify the search for a clinically sensible plan. Methods: A permissible dosimetric uncertainty is introduced for each of the structures to balance their conflicting dosimetric requirements. The inverse planning is then formulated as a convex feasibility problem, which aims to generate plans with acceptable dosimetric uncertainties. A sequential procedure (SP) is derived to decompose the model into three submodels to constrain the uncertainty in the planning target volume (PTV), the critical structures, and all other structures to spare, sequentially. The proposed technique is applied to plan a liver case and a head-and-neck case and compared with a conventional approach. Results: Our results show that the strategy is able to generate clinically sensible plans with little trial-and-error. In the case of liver IMRT, the fractional volumes to liver and heart above 20Gy are found to be 22% and 10%, respectively, which are 15.1% and 33.3% lower than that of the counterpart conventional plan while maintaining the same PTV coverage. The planning of the head and neck IMRT show the same level of success, with the DVHs for all organs at risk and PTV very competitive to a counterpart plan. Conclusion: A new inverse planning framework has been established. With physically more meaningful modeling of the inter-structural tradeoff, the technique enables us to substantially reduce the need for trial-and-error adjustment of the model parameters and opens new opportunities of incorporating prior

WE-AB-209-02: A New Inverse Planning Framework with Principle-Based Modeling of Inter-Structural Dosimetric Tradeoffs

Energy Technology Data Exchange (ETDEWEB)

Liu, H; Dong, P; Xing, L [Stanford University School of Medicine, Stanford, CA (United States)

2016-06-15

Purpose: Traditional radiotherapy inverse planning relies on the weighting factors to phenomenologically balance the conflicting criteria for different structures. The resulting manual trial-and-error determination of the weights has long been recognized as the most time-consuming part of treatment planning. The purpose of this work is to develop an inverse planning framework that parameterizes the inter-structural dosimetric tradeoff among with physically more meaningful quantities to simplify the search for a clinically sensible plan. Methods: A permissible dosimetric uncertainty is introduced for each of the structures to balance their conflicting dosimetric requirements. The inverse planning is then formulated as a convex feasibility problem, which aims to generate plans with acceptable dosimetric uncertainties. A sequential procedure (SP) is derived to decompose the model into three submodels to constrain the uncertainty in the planning target volume (PTV), the critical structures, and all other structures to spare, sequentially. The proposed technique is applied to plan a liver case and a head-and-neck case and compared with a conventional approach. Results: Our results show that the strategy is able to generate clinically sensible plans with little trial-and-error. In the case of liver IMRT, the fractional volumes to liver and heart above 20Gy are found to be 22% and 10%, respectively, which are 15.1% and 33.3% lower than that of the counterpart conventional plan while maintaining the same PTV coverage. The planning of the head and neck IMRT show the same level of success, with the DVHs for all organs at risk and PTV very competitive to a counterpart plan. Conclusion: A new inverse planning framework has been established. With physically more meaningful modeling of the inter-structural tradeoff, the technique enables us to substantially reduce the need for trial-and-error adjustment of the model parameters and opens new opportunities of incorporating prior

Coupling/Tradeoff Analysis and Novel Containment Control for Reactive Power, Output Voltage in Islanded Micro-Grid

DEFF Research Database (Denmark)

Han, Renke; Meng, Lexuan; Guerrero, Josep M.

2016-01-01

Based on the hierarchical control structure in islanded Micro-Grid (MG) systems, the coupling/tradeoff effects in different control levels are analyzed in details. In the primary level, analyses of the coupling effects among droop control gains, line impedance differences, output reactive power...

Seasonal and within-canopy variation in shoot-scale resource-use efficiency trade-offs in a Norway spruce stand.

Science.gov (United States)

Tarvainen, Lasse; Räntfors, Mats; Wallin, Göran

2015-11-01

Previous leaf-scale studies of carbon assimilation describe short-term resource-use efficiency (RUE) trade-offs where high use efficiency of one resource requires low RUE of another. However, varying resource availabilities may cause long-term RUE trade-offs to differ from the short-term patterns. This may have important implications for understanding canopy-scale resource use and allocation. We used continuous gas exchange measurements collected at five levels within a Norway spruce, Picea abies (L.) karst., canopy over 3 years to assess seasonal differences in the interactions between shoot-scale resource availability (light, water and nitrogen), net photosynthesis (An ) and the use efficiencies of light (LUE), water (WUE) and nitrogen (NUE) for carbon assimilation. The continuous data set was used to develop and evaluate multiple regression models for predicting monthly shoot-scale An . These models showed that shoot-scale An was strongly dependent on light availability and was generally well described with simple one- or two-parameter models. WUE peaked in spring, NUE in summer and LUE in autumn. However, the relative importance of LUE for carbon assimilation increased with canopy depth at all times. Our results suggest that accounting for seasonal and within-canopy trade-offs may be important for RUE-based modelling of canopy carbon uptake. © 2015 John Wiley & Sons Ltd.

Specifying design conservatism: Worst case versus probabilistic analysis

Science.gov (United States)

Miles, Ralph F., Jr.

1993-01-01

Design conservatism is the difference between specified and required performance, and is introduced when uncertainty is present. The classical approach of worst-case analysis for specifying design conservatism is presented, along with the modern approach of probabilistic analysis. The appropriate degree of design conservatism is a tradeoff between the required resources and the probability and consequences of a failure. A probabilistic analysis properly models this tradeoff, while a worst-case analysis reveals nothing about the probability of failure, and can significantly overstate the consequences of failure. Two aerospace examples will be presented that illustrate problems that can arise with a worst-case analysis.

Coding-Spreading Tradeoff in CDMA Systems

National Research Council Canada - National Science Library

Bolas, Eduardo

2002-01-01

.... Comparing different combinations of coding and spreading with a traditional DS-CDMA, as defined in the IS-95 standard, allows the criteria to be defined for the best coding-spreading tradeoff in CDMA systems...

General tradeoff relations of quantum nonlocality in the Clauser–Horne–Shimony–Holt scenario

Energy Technology Data Exchange (ETDEWEB)

Su, Hong-Yi, E-mail: hongyisu@chonnam.ac.kr [Department of Physics Education, Chonnam National University, Gwangju 500-757 (Korea, Republic of); Chen, Jing-Ling [Theoretical Physics Division, Chern Institute of Mathematics, Nankai University, Tianjin 300071 (China); Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543 (Singapore); Hwang, Won-Young, E-mail: wyhwang@jnu.ac.kr [Department of Physics Education, Chonnam National University, Gwangju 500-757 (Korea, Republic of)

2017-02-15

General tradeoff relations present in nonlocal correlations of bipartite systems are studied, regardless of any specific quantum states and measuring directions. Extensions to multipartite scenarios are possible and very promising. Tsirelson’s bound can be derived out in particular. The close connection with uncertainty relations is also presented and discussed. - Highlights: • Quantum violation of CHSH inequalities is found to satisfy tradeoff relations. • Tsirelson’s bound for quantum mechanics can be directly implied from these tradeoffs. • Tradeoff relations shed new light on uncertainty relations in summation forms.

Digital Technology in Teaching International Business: Is a Tradeoff between Richness and Reach Required?

Science.gov (United States)

Wymbs, Cliff; Kijne, Hugo

2003-01-01

This analysis extends the traditional marketing tradeoffs between richness (depth of knowledge) and reach (geographic area coverage) to the emerging technology-mediated education industry, and then specifically evaluates their effect on the teaching of international business. It asserts that interactive learning, particularly as it applies to team…

The Geometry of Nutrient Space-Based Life-History Trade-Offs: Sex-Specific Effects of Macronutrient Intake on the Trade-Off between Encapsulation Ability and Reproductive Effort in Decorated Crickets.

Science.gov (United States)

Rapkin, James; Jensen, Kim; Archer, C Ruth; House, Clarissa M; Sakaluk, Scott K; Castillo, Enrique Del; Hunt, John

2018-04-01

Life-history theory assumes that traits compete for limited resources, resulting in trade-offs. The most commonly manipulated resource in empirical studies is the quantity or quality of diet. Recent studies using the geometric framework for nutrition, however, suggest that trade-offs are often regulated by the intake of specific nutrients, but a formal approach to identify and quantify the strength of such trade-offs is lacking. We posit that trade-offs occur whenever life-history traits are maximized in different regions of nutrient space, as evidenced by nonoverlapping 95% confidence regions of the global maximum for each trait and large angles (θ) between linear nutritional vectors and Euclidean distances (d) between global maxima. We then examined the effects of protein and carbohydrate intake on the trade-off between reproduction and aspects of immune function in male and female Gryllodes sigillatus. Female encapsulation ability and egg production increased with the intake of both nutrients, whereas male encapsulation ability increased with protein intake but calling effort increased with carbohydrate intake. The trade-offs between traits was therefore larger in males than in females, as demonstrated by significant negative correlations between the traits in males, nonoverlapping 95% confidence regions, and larger estimates of θ and d. Under dietary choice, the sexes had similar regulated intakes, but neither optimally regulated nutrient intake for maximal trait expression. We highlight the fact that greater consideration of specific nutrient intake is needed when examining nutrient space-based trade-offs.

A case study on the influence of multiscale modelling in design and structural analysis

DEFF Research Database (Denmark)

Nicholas, Paul; Zwierzycki, Mateusz; La Magna, Riccardo

2017-01-01

. To illustrate the concept of multi-scale modelling, the prototype of a bridge structure that was realised making use of this information transfer between models will be presented. The prototype primarily takes advantage of the geometric and material stiffening effect of incremental metal forming. The local......The current paper discusses the role of multi-scale modelling within the context of design and structural analysis. Depending on the level of detail, a design model may retain, lose or enhance key information. The term multi-scale refers to the break-down of a design and analysis task into multiple...... levels of detail and the transfer of this information between models. Focusing on the influence that different models have on the analysed performance of the structure, the paper will discuss the advantages and trade-offs of coupling multiple levels of abstraction in terms of design and structure...

Information-disturbance tradeoff in quantum measurements

International Nuclear Information System (INIS)

Maccone, Lorenzo

2006-01-01

We present a simple information-disturbance tradeoff relation valid for any general measurement apparatus: The disturbance between input and output states is lower bounded by the information the apparatus provides in distinguishing these two states

Efficient operation of a multi-purpose reservoir in Chile: Tradeoffs between irrigation and hydropower production

Science.gov (United States)

Gonzalez Cabrera, J. M., Sr.; Olivares, M. A.

2015-12-01

This study proposes a method to develop efficient operational policies for a reservoir the southern Chile. The main water uses in this system are hydropower and irrigation, with conflicting seasonal demands. The conflict between these two uses is currently managed through a so-called "irrigation agreement" which defines a series of operational conditions on the reservoir by restricting volumes used for power production depending on reservoir storage level. Other than that, the reservoir operation is driven by cost-minimization over the power grid. Recent evidence shows an increasing degree of conflict in this basin, which suggests that the static approach of irrigation agreements, might no longer be appropriate. Moreover, this agreement could be revised in light of decreased water availability. This problem poses a challenge related to the spatial scope of analysis. Thus, irrigation benefits are driven by decisions made within the basin, whereas hydropower benefits depend on the operation of the entire power grid. Exploring the tradeoffs between these two water uses involves modeling both scales. The proposed methodology integrates information from both a grid-wide power operations model and a basin-wide agro-economic model into a decision model for optimal reservoir operation. The first model, a hydrothermal coordination tool, schedules power production by each plant in the grid, and allows capturing technical and economic aspects to the operation of hydropower reservoirs. The agro-economic model incorporates economic features of irrigation in the basin, and allows obtaining irrigation water demand functions. Finally, the results of both models are integrated into a single model for optimal reservoir operation considering the tradeoffs between the two uses. The result of the joint operation of water resources, show a flexible coordination of uses, revealing the opportunity cost of irrigation, which it gives the possibility of negotiating transfers of water to

Development of an integrated model for energy systems planning and carbon dioxide mitigation under uncertainty - Tradeoffs between two-level decision makers.

Science.gov (United States)

Jin, S W; Li, Y P; Xu, L P

2018-07-01

A bi-level fuzzy programming (BFLP) method was developed for energy systems planning (ESP) and carbon dioxide (CO 2 ) mitigation under uncertainty. BFLP could handle fuzzy information and leader-follower problem in decision-making processes. It could also address the tradeoffs among different decision makers in two decision-making levels through prioritizing the most important goal. Then, a BFLP-ESP model was formulated for planning energy system of Beijing, in which the upper-level objective is to minimize CO 2 emission and the lower-level objective is to minimize the system cost. Results provided a range of decision alternatives that corresponded to a tradeoff between system optimality and reliability under uncertainty. Compared to the single-level model with a target to minimize system cost, the amounts of pollutant/CO 2 emissions from BFLP-ESP were reduced since the study system would prefer more clean energies (i.e. natural gas, LPG and electricity) to replace coal fuel. Decision alternatives from BFLP were more beneficial for supporting Beijing to adjust its energy mix and enact its emission-abatement policy. Results also revealed that the low-carbon policy for power plants (e.g., shutting down all coal-fired power plants) could lead to a potentially increment of imported energy for Beijing, which would increase the risk of energy shortage. The findings could help decision makers analyze the interactions between different stakeholders in ESP and provide useful information for policy design under uncertainty. Copyright © 2018 Elsevier Inc. All rights reserved.

Visualising Pareto-optimal trade-offs helps move beyond monetary-only criteria for water management decisions

Science.gov (United States)

Hurford, Anthony; Harou, Julien

2014-05-01

Water related eco-system services are important to the livelihoods of the poorest sectors of society in developing countries. Degradation or loss of these services can increase the vulnerability of people decreasing their capacity to support themselves. New approaches to help guide water resources management decisions are needed which account for the non-market value of ecosystem goods and services. In case studies from Brazil and Kenya we demonstrate the capability of many objective Pareto-optimal trade-off analysis to help decision makers balance economic and non-market benefits from the management of existing multi-reservoir systems. A multi-criteria search algorithm is coupled to a water resources management simulator of each basin to generate a set of Pareto-approximate trade-offs representing the best case management decisions. In both cases, volume dependent reservoir release rules are the management decisions being optimised. In the Kenyan case we further assess the impacts of proposed irrigation investments, and how the possibility of new investments impacts the system's trade-offs. During the multi-criteria search (optimisation), performance of different sets of management decisions (policies) is assessed against case-specific objective functions representing provision of water supply and irrigation, hydropower generation and maintenance of ecosystem services. Results are visualised as trade-off surfaces to help decision makers understand the impacts of different policies on a broad range of stakeholders and to assist in decision-making. These case studies show how the approach can reveal unexpected opportunities for win-win solutions, and quantify the trade-offs between investing to increase agricultural revenue and negative impacts on protected ecosystems which support rural livelihoods.

Energy Efficiency - Spectral Efficiency Trade-off: A Multiobjective Optimization Approach

KAUST Repository

Amin, Osama

2015-04-23

In this paper, we consider the resource allocation problem for energy efficiency (EE) - spectral efficiency (SE) trade-off. Unlike traditional research that uses the EE as an objective function and imposes constraints either on the SE or achievable rate, we propound a multiobjective optimization approach that can flexibly switch between the EE and SE functions or change the priority level of each function using a trade-off parameter. Our dynamic approach is more tractable than the conventional approaches and more convenient to realistic communication applications and scenarios. We prove that the multiobjective optimization of the EE and SE is equivalent to a simple problem that maximizes the achievable rate/SE and minimizes the total power consumption. Then we apply the generalized framework of the resource allocation for the EE-SE trade-off to optimally allocate the subcarriers’ power for orthogonal frequency division multiplexing (OFDM) with imperfect channel estimation. Finally, we use numerical results to discuss the choice of the trade-off parameter and study the effect of the estimation error, transmission power budget and channel-to-noise ratio on the multiobjective optimization.

Energy Efficiency - Spectral Efficiency Trade-off: A Multiobjective Optimization Approach

KAUST Repository

Amin, Osama; Bedeer, Ebrahim; Ahmed, Mohamed; Dobre, Octavia

2015-01-01

In this paper, we consider the resource allocation problem for energy efficiency (EE) - spectral efficiency (SE) trade-off. Unlike traditional research that uses the EE as an objective function and imposes constraints either on the SE or achievable rate, we propound a multiobjective optimization approach that can flexibly switch between the EE and SE functions or change the priority level of each function using a trade-off parameter. Our dynamic approach is more tractable than the conventional approaches and more convenient to realistic communication applications and scenarios. We prove that the multiobjective optimization of the EE and SE is equivalent to a simple problem that maximizes the achievable rate/SE and minimizes the total power consumption. Then we apply the generalized framework of the resource allocation for the EE-SE trade-off to optimally allocate the subcarriers’ power for orthogonal frequency division multiplexing (OFDM) with imperfect channel estimation. Finally, we use numerical results to discuss the choice of the trade-off parameter and study the effect of the estimation error, transmission power budget and channel-to-noise ratio on the multiobjective optimization.

Epistemic and aleatory uncertainties in integrated deterministic and probabilistic safety assessment: Tradeoff between accuracy and accident simulations

International Nuclear Information System (INIS)

Karanki, D.R.; Rahman, S.; Dang, V.N.; Zerkak, O.

2017-01-01

The coupling of plant simulation models and stochastic models representing failure events in Dynamic Event Trees (DET) is a framework used to model the dynamic interactions among physical processes, equipment failures, and operator responses. The integration of physical and stochastic models may additionally enhance the treatment of uncertainties. Probabilistic Safety Assessments as currently implemented propagate the (epistemic) uncertainties in failure probabilities, rates, and frequencies; while the uncertainties in the physical model (parameters) are not propagated. The coupling of deterministic (physical) and probabilistic models in integrated simulations such as DET allows both types of uncertainties to be considered. However, integrated accident simulations with epistemic uncertainties will challenge even today's high performance computing infrastructure, especially for simulations of inherently complex nuclear or chemical plants. Conversely, intentionally limiting computations for practical reasons would compromise accuracy of results. This work investigates how to tradeoff accuracy and computations to quantify risk in light of both uncertainties and accident dynamics. A simple depleting tank problem that can be solved analytically is considered to examine the adequacy of a discrete DET approach. The results show that optimal allocation of computational resources between epistemic and aleatory calculations by means of convergence studies ensures accuracy within a limited budget. - Highlights: • Accident simulations considering uncertainties require intensive computations. • Tradeoff between accuracy and accident simulations is a challenge. • Optimal allocation between epistemic & aleatory computations ensures the tradeoff. • Online convergence gives an early indication of computational requirements. • Uncertainty propagation in DDET is examined on a tank problem solved analytically.

Analysis and Evaluation of Performance Gains and Tradeoffs for Massive MIMO Systems

Directory of Open Access Journals (Sweden)

Saba Qasim Jabbar

2016-09-01

Full Text Available Massive MIMO technique offers significant performance gains for the future of wireless communications via improving the spectral efficiency, energy efficiency and the channel quality with simple linear processing such as maximum-ratio transmission (MRT or zero-forcing (ZF by providing each user a large degree of freedom. In this paper, the system performance gains are studied in a multi-cell downlink massive MIMO system under the main considerations such as perfect channel estimation, imperfect channel estimation and the effect of interference among cells due to pilot sequences contamination. Then, mathematical expressions are derived for these gains i.e., spatial multiplexing gain, array gain and spatial diversity gain. After that, essential tradeoffs among these gains are considered under the effect of non-orthogonal interference, these tradeoffs are: spatial diversity gain vs. spatial multiplexing gain and array gain vs. spatial multiplexing gain. Simulation results show that the unbounded number of base station antennas boosts the array gain through concentrating the energy to spatial directions where users are sited, hence diminishing loss in array gain due to pilot contamination. The simulation results reveal also that massive MIMO strengthens the spatial multiplexing gain through increasing the number of served users via the same system resources in spite the effect of inter-cell interference. Finally, the spatial diversity gain is measured in term of outage probability and the simulation results show that raising the number of antennas will improve the outage probability. Meanwhile increasing the number of served users will lead to degrade the outage probability per user due to non-orthogonal interference from other cells.

Preference Evaluation System for Construction Products Using QFD-TOPSIS Logic by Considering Trade-Off Technical Characteristics

Directory of Open Access Journals (Sweden)

Jaeho Cho

2017-01-01

Full Text Available This paper investigates the feasibility of quality function deployment, technique for the order of preference by similarity to ideal solution (QFD-TOPSIS in presenting user preferences for multiple alternatives, such as construction technologies, products, systems, and design solutions, with trade-off technical characteristics (TC. The original QFD as house of quality (HOQ defines the requirements and features as subjective matrix relations, which cause interpretations to vary across users and limit its industrial applications. QFD-TOPSIS is a new model that combines the benefits of QFD with those of TOPSIS, maintains the subjectivity and objectivity evaluation of the technical characteristics (TC, and rates the preferences by considering users’ individual propensity for requirements. In addition, QFD-TOPSIS rates the preferences through the reciprocal compensation effects of trade-off TC and filters unsuitable alternatives with predefined restrictive conditions. Trade-off refers to conflicts and/or contradictions between attributes, often arising in multicriteria decision-making. Users or project stakeholder groups define the priorities of trade-off TC that directly influence product preferences and decision-making. In the present study, we have developed a Web system based on the QFD-TOPSIS logic and tested its operation to verify its industrial applicability and viability for automatic quality evaluation.

Unexpected water impacts of energy-saving measures in the iron and steel sector: Tradeoffs or synergies?

International Nuclear Information System (INIS)

Wang, Can; Zheng, Xinzhu; Cai, Wenjia; Gao, Xue; Berrill, Peter

2017-01-01

Highlights: •Associated water impacts of individual energy conservation measures were evaluated. •Water-energy tradeoffs exist in the production process adjustment of iron sector. •Considering the water impacts can change the priority ranks of technology choice. -- Abstract: Moving towards integrated governance of water and energy requires balancing tradeoffs and taking advantage of synergies through specific technology choice. However, the water-energy conservation relationships of individual conservation measures in industries other than the water and energy sectors have not been investigated in detail. This study develops a hybrid model to estimate the associated water impacts of individual energy conservation measures, using China’s iron and steel industry as a case study. The results reveal that water-energy tradeoffs exist in the production process adjustment, which is conventionally promoted as a key energy-saving measure in iron and steel industry. It is found that replacing the Blast Oxygen Furnace (BOF) process with the Electric Arc Furnace (EAF) in 2007 could save 131–156 kg coal equivalent (kgce) (13.2–15.7%) of embodied energy per ton of crude steel (tcs) at the expenses of an additional 2.5–3.9 m 3 /tcs (10.6–16.4%) of water footprint. Nineteen energy efficiency technologies are studied in this research, and most of them are identified as having water-saving synergies except for the Low Temperature Rolling Technology. Taking these water impacts into consideration can update the priority ranks of the technology choices and inform policy decisions. Although this study focuses on China’s iron and steel sector, the methods and analysis can be extended to other countries, sectors, technologies and environmental impacts.

Ecosystem service trade-offs and their influencing factors: A case study in the Loess Plateau of China.

Science.gov (United States)

Feng, Qiang; Zhao, Wenwu; Fu, Bojie; Ding, Jingyi; Wang, Shuai

2017-12-31

Soil erosion control (SEC), carbon sequestration (CAS), and soil moisture (SMO) strongly interact in the semi-arid Loess Plateau. Since SMO has supportive effects on SEC and CAS, it can be considered as ecosystem service (ES), and there is an immediate need to coordinate the relationships among these ecosystem services (ESs) to promote the sustainability of vegetation recovery. In this study, we quantified the ESs, ES trade-offs, and the environmental factors in 151 sample plots in the Ansai watershed, and we used a redundancy analysis (RDA) to clarify the effects of environmental factors on these ESs and their trade-offs. The results were as follows: (1) the general trend in the SEC of vegetation types was Robinia pseudoacacia (CH)>native grass (NG)>small arbor (ST)>Hippophae rhamnoides (SJ)>artificial grass (AG)>Caragana korshinskii (NT)>apple orchard (GY)>crop (CP); the CAS trend was CH>SJ>NT>AG>CP>ST>GY>NG; and the SMO trend was CP>NG>GY>AG>SJ>ST>CH>NT. (2) For SEC-SMO trade-offs, the influence of vegetation type, altitude, silt and sand composition was dominant. The arrangement of NG, AG, and SJ could decrease the extent of the trade-offs. (3) For CAS-SMO trade-offs, vegetation coverage and types were the dominant factors, but the effects were not complex. The extent of these trade-offs was lowest for NT, and that for SJ was the second lowest. (4) Considering the relationships among the three ESs, SJ was the most appropriate afforestation plant. Combing the vegetation types, slope position, slope gradient, and soil properties could regulate these ES relationships. The dominant factors influencing ES trade-offs varied among the different soil layers, so we must consider the corresponding influencing factors to regulate ESs. Moreover, manual management measures were also important for coordinating the ES relationships. Our research provides a better understanding of the mechanisms influencing the relationships among ESs. Copyright © 2017 Elsevier B.V. All

Spatially and Temporally Resolved Analysis of Environmental Trade-Offs in Electricity Generation.

Science.gov (United States)

Peer, Rebecca A M; Garrison, Jared B; Timms, Craig P; Sanders, Kelly T

2016-04-19

The US power sector is a leading contributor of emissions that affect air quality and climate. It also requires a lot of water for cooling thermoelectric power plants. Although these impacts affect ecosystems and human health unevenly in space and time, there has been very little quantification of these environmental trade-offs on decision-relevant scales. This work quantifies hourly water consumption, emissions (i.e., carbon dioxide, nitrogen oxides, and sulfur oxides), and marginal heat rates for 252 electricity generating units (EGUs) in the Electric Reliability Council of Texas (ERCOT) region in 2011 using a unit commitment and dispatch model (UC&D). Annual, seasonal, and daily variations, as well as spatial variability are assessed. When normalized over the grid, hourly average emissions and water consumption intensities (i.e., output per MWh) are found to be highest when electricity demand is the lowest, as baseload EGUs tend to be the most water and emissions intensive. Results suggest that a large fraction of emissions and water consumption are caused by a small number of power plants, mainly baseload coal-fired generators. Replacing 8-10 existing power plants with modern natural gas combined cycle units would result in reductions of 19-29%, 51-55%, 60-62%, and 13-27% in CO2 emissions, NOx emissions, SOx emissions, and water consumption, respectively, across the ERCOT region for two different conversion scenarios.

Balancing tradeoffs in the Denali Wilderness: an expanded approach to normative research using stated choice analysis

Science.gov (United States)

Steven R. Lawson; Robert Manning

2002-01-01

Wilderness experiences are thought to be comprised of or defined by three dimensions, including social, resource, and management conditions. Decisions about how to manage wilderness recreation in Denali National Park involve potential tradeoffs among the conditions of resource, social, and managerial attributes of the wilderness experience. This study expands the...

Trade-offs Between Socio-economic Development and Ecosystem Health under Changing Water Availability

Science.gov (United States)

Nazemi, A.; Hassanzadeh, E.; Elshorbagy, A. A.; Wheater, H. S.; Gober, P.; Jardine, T.; Lindenschmidt, K. E.

2017-12-01

Natural and human water systems at regional scales are often developed around key characteristics of streamflow. As a result, changes in streamflow regime can affect both socio-economic activities and freshwater ecosystems. In addition to natural variability and/or climate change, extensive water resource management to support socio-economic growth has also changed streamflow regimes. This study aims at understanding the trade-offs between agricultural expansion in the province of Saskatchewan, Canada, and alterations in the ecohydrological characteristics of the Saskatchewan River Delta (SRD) located downstream. Changes in climate along with extensive water resource management have altered the upstream flow regime. Moreover, Saskatchewan is investigating the possible expansion of irrigated agriculture to boost the provincial economy. To evaluate trade-offs across a range of possible scenarios for streamflow changes, the potential increase in provincial net benefit versus potential vulnerability of the SRD was assessed using perturbed flow realizations along with scenarios of irrigation expansion as input to an integrated water resource system model. This study sheds light on the potential variability in trade-offs between economic benefits and ecosystem health under a range of streamflow conditions, with the aim of informing decisions that can benefit both natural and human water systems.

Functional Trade-Offs in Promiscuous Enzymes Cannot Be Explained by Intrinsic Mutational Robustness of the Native Activity.

Directory of Open Access Journals (Sweden)

Miriam Kaltenbach

2016-10-01

Full Text Available The extent to which an emerging new function trades off with the original function is a key characteristic of the dynamics of enzyme evolution. Various cases of laboratory evolution have unveiled a characteristic trend; a large increase in a new, promiscuous activity is often accompanied by only a mild reduction of the native, original activity. A model that associates weak trade-offs with "evolvability" was put forward, which proposed that enzymes possess mutational robustness in the native activity and plasticity in promiscuous activities. This would enable the acquisition of a new function without compromising the original one, reducing the benefit of early gene duplication and therefore the selection pressure thereon. Yet, to date, no experimental study has examined this hypothesis directly. Here, we investigate the causes of weak trade-offs by systematically characterizing adaptive mutations that occurred in two cases of evolutionary transitions in enzyme function: (1 from phosphotriesterase to arylesterase, and (2 from atrazine chlorohydrolase to melamine deaminase. Mutational analyses in various genetic backgrounds revealed that, in contrast to the prevailing model, the native activity is less robust to mutations than the promiscuous activity. For example, in phosphotriesterase, the deleterious effect of individual mutations on the native phosphotriesterase activity is much larger than their positive effect on the promiscuous arylesterase activity. Our observations suggest a revision of the established model: weak trade-offs are not caused by an intrinsic robustness of the native activity and plasticity of the promiscuous activity. We propose that upon strong adaptive pressure for the new activity without selection against the original one, selected mutations will lead to the largest possible increases in the new function, but whether and to what extent they decrease the old function is irrelevant, creating a bias towards initially weak

Parent-offspring conflict and the genetic trade-offs shaping parental investment.

Science.gov (United States)

Kölliker, Mathias; Boos, Stefan; Wong, Janine W Y; Röllin, Lilian; Stucki, Dimitri; Raveh, Shirley; Wu, Min; Meunier, Joël

2015-04-16

The genetic conflict between parents and their offspring is a cornerstone of kin selection theory and the gene-centred view of evolution, but whether it actually occurs in natural systems remains an open question. Conflict operates only if parenting is driven by genetic trade-offs between offspring performance and the parent's ability to raise additional offspring, and its expression critically depends on the shape of these trade-offs. Here we investigate the occurrence and nature of genetic conflict in an insect with maternal care, the earwig Forficula auricularia. Specifically, we test for a direct response to experimental selection on female future reproduction and correlated responses in current offspring survival, developmental rate and growth. The results demonstrate genetic trade-offs that differ in shape before and after hatching. Our study not only provides direct evidence for parent-offspring conflict but also highlights that conflict is not inevitable and critically depends on the genetic trade-offs shaping parental investment.

Time and outcome framing in intertemporal tradeoffs.

Science.gov (United States)

Scholten, Marc; Read, Daniel

2013-07-01

A robust anomaly in intertemporal choice is the delay-speedup asymmetry: Receipts are discounted more, and payments are discounted less, when delayed than when expedited over the same interval. We developed 2 versions of the tradeoff model (Scholten & Read, 2010) to address such situations, in which an outcome is expected at a given time but then its timing is changed. The outcome framing model generalizes the approach taken by the hyperbolic discounting model (Loewenstein & Prelec, 1992): Not obtaining a positive outcome when expected is a worse than expected state, to which people are over-responsive, or hypersensitive, and not incurring a negative outcome when expected is a better than expected state, to which people are under-responsive, or hyposensitive. The time framing model takes a new approach: Delaying a positive outcome or speeding up a negative one involves a loss of time to which people are hypersensitive, and speeding up a positive outcome or delaying a negative one involves a gain of time to which people are hyposensitive. We compare the models on their quantitative predictions of indifference data from matching and preference data from choice. The time framing model systematically outperforms the outcome framing model. PsycINFO Database Record (c) 2013 APA, all rights reserved.

Waste Classification based on Waste Form Heat Generation in Advanced Nuclear Fuel Cycles Using the Fuel-Cycle Integration and Tradeoffs (FIT) Model

Energy Technology Data Exchange (ETDEWEB)

Denia Djokic; Steven J. Piet; Layne F. Pincock; Nick R. Soelberg

2013-02-01

This study explores the impact of wastes generated from potential future fuel cycles and the issues presented by classifying these under current classification criteria, and discusses the possibility of a comprehensive and consistent characteristics-based classification framework based on new waste streams created from advanced fuel cycles. A static mass flow model, Fuel-Cycle Integration and Tradeoffs (FIT), was used to calculate the composition of waste streams resulting from different nuclear fuel cycle choices. This analysis focuses on the impact of waste form heat load on waste classification practices, although classifying by metrics of radiotoxicity, mass, and volume is also possible. The value of separation of heat-generating fission products and actinides in different fuel cycles is discussed. It was shown that the benefits of reducing the short-term fission-product heat load of waste destined for geologic disposal are neglected under the current source-based radioactive waste classification system , and that it is useful to classify waste streams based on how favorable the impact of interim storage is in increasing repository capacity.

Balancing ecosystem services with energy and food security - assessing trade-offs for reservoir operation and irrigation investment in Kenya's Tana basin

Science.gov (United States)

Hurford, A. P.; Harou, J. J.

2014-01-01

Competition for water between key economic sectors and the environment means agreeing on allocation is challenging. Managing releases from the three major dams in Kenya's Tana River basin with its 4.4 million inhabitants, 567 MW of installed hydropower capacity, 33 000 ha of irrigation and ecologically important wetlands and forests is a pertinent example. This research seeks to identify and help decision-makers visualise reservoir management strategies which result in the best possible (Pareto-optimal) allocation of benefits between sectors. Secondly we seek to show how trade-offs between achievable benefits shift with the implementation of new proposed rice, cotton and biofuel irrigation projects. To identify the Pareto-optimal trade-offs we link a water resources management model to a multi-criteria search algorithm. The decisions or "levers" of the management problem are volume dependent release rules for the three major dams and extent of investment in new irrigation schemes. These decisions are optimised for objectives covering provision of water supply and irrigation, energy generation and maintenance of ecosystem services which underpin tourism and local livelihoods. Visual analytic plots allow decision makers to assess multi-reservoir rule-sets by understanding their impacts on different beneficiaries. Results quantify how economic gains from proposed irrigation schemes trade-off against disturbance of the flow regime which supports ecosystem services. Full implementation of the proposed schemes is shown to be Pareto-optimal, but at high environmental and social cost. The clarity and comprehensiveness of "best-case" trade-off analysis is a useful vantage point from which to tackle the interdependence and complexity of water-energy-food "nexus" challenges.

Characterizing Coastal Ecosystem Service Trade-offs with Future Urban Development in a Tropical City.

Science.gov (United States)

Richards, Daniel R; Friess, Daniel A

2017-11-01

With rapid urbanization in the coastal zone and increasing habitat losses, it is imperative to understand how urban development affects coastal biodiversity and ecosystem service provision. Furthermore, it is important to understand how habitat fragments can best be incorporated into broader land use planning and coastal management, in order to maximize the environmental benefits they provide. In this study, we characterized the trade-offs between (a) urban development and individual mangrove environmental indicators (habitat quality and ecosystem services), and (b) between different environmental indicators in the tropical nation of Singapore. A range of biological, biophysical, and cultural indicators, including carbon, charcoal production, support for offshore fisheries, recreation, and habitat quality for a threatened species were quantified using field-based, remote sensing, and expert survey methods. The shape of the trade-off Pareto frontiers was analyzed to assess the sensitivity of environmental indicators for development. When traded off individually with urban development, four out of five environmental indicators were insensitive to development, meaning that relatively minor degradation of the indicator occurred while development was below a certain threshold, although indicator loss accelerated once this threshold was reached. Most of the pairwise relationships between the five environmental indicators were synergistic; only carbon storage and charcoal production, and charcoal production and recreational accessibility showed trade-offs. Trade-off analysis and land use optimization using Pareto frontiers could be a useful decision-support tool for understanding how changes in land use and coastal management will impact the ability of ecosystems to provide environmental benefits.

Characterizing Coastal Ecosystem Service Trade-offs with Future Urban Development in a Tropical City

Science.gov (United States)

Richards, Daniel R.; Friess, Daniel A.

2017-11-01

With rapid urbanization in the coastal zone and increasing habitat losses, it is imperative to understand how urban development affects coastal biodiversity and ecosystem service provision. Furthermore, it is important to understand how habitat fragments can best be incorporated into broader land use planning and coastal management, in order to maximize the environmental benefits they provide. In this study, we characterized the trade-offs between (a) urban development and individual mangrove environmental indicators (habitat quality and ecosystem services), and (b) between different environmental indicators in the tropical nation of Singapore. A range of biological, biophysical, and cultural indicators, including carbon, charcoal production, support for offshore fisheries, recreation, and habitat quality for a threatened species were quantified using field-based, remote sensing, and expert survey methods. The shape of the trade-off Pareto frontiers was analyzed to assess the sensitivity of environmental indicators for development. When traded off individually with urban development, four out of five environmental indicators were insensitive to development, meaning that relatively minor degradation of the indicator occurred while development was below a certain threshold, although indicator loss accelerated once this threshold was reached. Most of the pairwise relationships between the five environmental indicators were synergistic; only carbon storage and charcoal production, and charcoal production and recreational accessibility showed trade-offs. Trade-off analysis and land use optimization using Pareto frontiers could be a useful decision-support tool for understanding how changes in land use and coastal management will impact the ability of ecosystems to provide environmental benefits.

Tradeoffs in the quest for climate smart agricultural intensification in Mato Grosso, Brazil

Science.gov (United States)

Gil, Juliana D. B.; Garrett, Rachael D.; Rotz, Alan; Daioglou, Vassilis; Valentim, Judson; Pires, Gabrielle F.; Costa, Marcos H.; Lopes, Luciano; Reis, Julio C.

2018-06-01

Low productivity cattle ranching, with its linkages to rural poverty, deforestation and greenhouse gas (GHG) emissions, remains one of the largest sustainability challenges in Brazil and has impacts worldwide. There is a nearly universal call to intensify extensive beef cattle production systems to spare land for crop production and nature and to meet Brazil’s Intended Nationally Determined Contribution to reducing global climate change. However, different interventions aimed at the intensification of livestock systems in Brazil may involve substantial social and environmental tradeoffs. Here we examine these tradeoffs using a whole-farm model calibrated for the Brazilian agricultural frontier state of Mato Grosso, one of the largest soybean and beef cattle production regions in the world. Specifically, we compare the costs and benefits of a typical extensive, continuously grazed cattle system relative to a specialized soybean production system and two improved cattle management strategies (rotational grazing and integrated soybean-cattle) under different climate scenarios. We found clear tradeoffs in GHG and nitrogen emissions, climate resilience, and water and energy use across these systems. Relative to continuously grazed or rotationally grazed cattle systems, the integreated soybean-cattle system showed higher food production and lower GHG emissions per unit of human digestible protein, as well as increased resilience under climate change (both in terms of productivity and financial returns). All systems suffered productivity and profitability losses under severe climate change, highlighting the need for climate smart agricultural development strategies in the region. By underscoring the economic feasibility of improving the performance of cattle systems, and by quantifying the tradeoffs of each option, our results are useful for directing agricultural and climate policy.

Compartmental modeling alternatives for kinetic analysis of pet neurotransmitter receptor studies

International Nuclear Information System (INIS)

Koeppe, R.A.

1991-01-01

With the increased interest in studying neurotransmitter and receptor function in vivo, imaging procedures using positron emission tomography have presented new challenges for kinetic modeling and analysis of data. The in vivo behavior of radiolabeled markers for examining these neurotransmitter systems can be quite complex and, therefore, the implementation of compartmental models for data analysis is similarly complex. Often, the variability in the estimates of model parameters representing neurotransmitter or receptor densities, association and dissociation rates, or rates of incorporation or turnover does not permit reliable interpretation of the data. When less complex analyses are used, these model parameters may be biased and thus also do not yield the information being sought. Examination of trade-offs between uncertainty and bias in the parameters of interest may be used to select a compartmental model configuration with an appropriate level of complexity. Modeling alternatives will be discussed for radioligands with varying kinetic properties, such as those that bind reversibly and rapidly and others that bind nearly irreversibly. Specific problems, such as those occurring when a radioligand is open-quotes flow limitedclose quotes also will be discussed

Intertemporal Risk-Return Trade-off in Foreign Exchange Rates

OpenAIRE

Christiansen, Charlotte

2010-01-01

We investigate the intertemporal risk-return trade-off of foreign ex-change (FX) rates for ten currencies quoted against the USD. For each currency,we use three risk measures simultaneously that pertain to that currency; its re-alized volatility, its realized skewness, and its value-at-risk. We apply monthlyFX excess returns and monthly FX risk measures calculated from daily ob-servations. We find that there is a positive and signi…cant contemporaneousrisk-return trade-off for most currencies...

Trade-off preferences regarding adjuvant endocrine therapy among women with estrogen receptor-positive breast cancer.

NARCIS (Netherlands)

Wouters, H.; Maatman, G.A.; Dijk, L. van; Bouvy, M.L.; Vree, R.; Geffen, E.C.G. van; Nortier, J.W.; Stiggelbout, A.M.

2013-01-01

Background: There is substantial nonadherence to effective adjuvant endocrine therapy for breast cancer prevention. We therefore examined patients' trade-offs between the efficacy, side-effects, and regimen duration, and whether trade-offs predicted nonadherence. Patients and methods: Trade-offs

Trade-off preferences regarding adjuvant endocrine therapy among women with estrogen receptor-positive breast cancer

NARCIS (Netherlands)

Wouters, H; Maatman, G A; Van Dijk, L; Bouvy, M L; Vree, R; Van Geffen, E C G; Nortier, J W; Stiggelbout, A M

BACKGROUND: There is substantial nonadherence to effective adjuvant endocrine therapy for breast cancer prevention. We therefore examined patients' trade-offs between the efficacy, side-effects, and regimen duration, and whether trade-offs predicted nonadherence. PATIENTS AND METHODS: Trade-offs

Identifying optimum performance trade-offs using a cognitively bounded rational analysis model of discretionary task interleaving.

Science.gov (United States)

Janssen, Christian P; Brumby, Duncan P; Dowell, John; Chater, Nick; Howes, Andrew

2011-01-01

We report the results of a dual-task study in which participants performed a tracking and typing task under various experimental conditions. An objective payoff function was used to provide explicit feedback on how participants should trade off performance between the tasks. Results show that participants' dual-task interleaving strategy was sensitive to changes in the difficulty of the tracking task and resulted in differences in overall task performance. To test the hypothesis that people select strategies that maximize payoff, a Cognitively Bounded Rational Analysis model was developed. This analysis evaluated a variety of dual-task interleaving strategies to identify the optimal strategy for maximizing payoff in each condition. The model predicts that the region of optimum performance is different between experimental conditions. The correspondence between human data and the prediction of the optimal strategy is found to be remarkably high across a number of performance measures. This suggests that participants were honing their behavior to maximize payoff. Limitations are discussed. Copyright © 2011 Cognitive Science Society, Inc.

Culture impacts the magnitude of the emotion-induced memory trade-off effect.

Science.gov (United States)

Gutchess, Angela; Garner, Lauryn; Ligouri, Laura; Konuk, Ayse Isilay; Boduroglu, Aysecan

2017-10-04

The present study assessed the extent to which culture impacts the emotion-induced memory trade-off effect. This trade-off effect occurs because emotional items are better remembered than neutral ones, but this advantage comes at the expense of memory for backgrounds such that neutral backgrounds are remembered worse when they occurred with an emotional item than with a neutral one. Cultures differ in their prioritisation of focal object versus contextual background information, with Westerners focusing more on objects and Easterners focusing more on backgrounds. Americans, a Western culture, and Turks, an Eastern-influenced culture, incidentally encoded positive, negative, and neutral items placed against neutral backgrounds, and then completed a surprise memory test with the items and backgrounds tested separately. Results revealed a reduced trade-off for Turks compared to Americans. Although both groups exhibited an emotional enhancement in item memory, Turks did not show a decrement in memory for backgrounds that had been paired with emotional items. These findings complement prior ones showing reductions in trade-off effects as a result of task instructions. Here, we suggest that a contextual-focus at the level of culture can mitigate trade-off effects in emotional memory.

Characteristics of the large corporation-based, bureaucratic model among oecd countries - an foi model analysis

Directory of Open Access Journals (Sweden)

Bartha Zoltán

2014-03-01

Full Text Available Deciding on the development path of the economy has been a delicate question in economic policy, not least because of the trade-off effects which immediately worsen certain economic indicators as steps are taken to improve others. The aim of the paper is to present a framework that helps decide on such policy dilemmas. This framework is based on an analysis conducted among OECD countries with the FOI model (focusing on future, outside and inside potentials. Several development models can be deduced by this method, out of which only the large corporation-based, bureaucratic model is discussed in detail. The large corporation-based, bureaucratic model implies a development strategy focused on the creation of domestic safe havens. Based on country studies, it is concluded that well-performing safe havens require the active participation of the state. We find that, in countries adhering to this model, business competitiveness is sustained through intensive public support, and an active role taken by the government in education, research and development, in detecting and exploiting special market niches, and in encouraging sectorial cooperation.

Speed and stamina trade-off in lacertid lizards.

Science.gov (United States)

Vanhooydonck, B; Van Damme, R; Aerts, P

2001-05-01

Morphological and physiological considerations suggest that sprinting ability and endurance capacity put conflicting demands on the design of an animal's locomotor apparatus and therefore cannot be maximized simultaneously. To test this hypothesis, we correlated size-corrected maximal sprint speed and stamina of 12 species of lacertid lizards. Phylogenetically independent contrasts of sprint speed and stamina showed a significant negative relationship, giving support to the idea of an evolutionary trade-off between the two performance measures. To test the hypothesis that the trade-off is mediated by a conflict in morphological requirements, we correlated both performance traits with snout-vent length, size-corrected estimates of body mass and limb length, and relative hindlimb length (the residuals of the relationship between hind- and forelimb length). Fast-running species had hindlimbs that were long compared to their forelimbs. None of the other size or shape variables showed a significant relationship with speed or endurance. We conclude that the evolution of sprint capacity may be constrained by the need for endurance capacity and vice versa, but the design conflict underlying this trade-off has yet to be identified.

Delay-area trade-off for MPRM circuits based on hybrid discrete particle swarm optimization

International Nuclear Information System (INIS)

Jiang Zhidi; Wang Zhenhai; Wang Pengjun

2013-01-01

Polarity optimization for mixed polarity Reed—Muller (MPRM) circuits is a combinatorial issue. Based on the study on discrete particle swarm optimization (DPSO) and mixed polarity, the corresponding relation between particle and mixed polarity is established, and the delay-area trade-off of large-scale MPRM circuits is proposed. Firstly, mutation operation and elitist strategy in genetic algorithm are incorporated into DPSO to further develop a hybrid DPSO (HDPSO). Then the best polarity for delay and area trade-off is searched for large-scale MPRM circuits by combining the HDPSO and a delay estimation model. Finally, the proposed algorithm is testified by MCNC Benchmarks. Experimental results show that HDPSO achieves a better convergence than DPSO in terms of search capability for large-scale MPRM circuits. (semiconductor integrated circuits)

Area Spectral Efficiency and Energy Efficiency Tradeoff in Ultradense Heterogeneous Networks

Directory of Open Access Journals (Sweden)

Lanhua Xiang

2017-01-01

Full Text Available In order to meet the demand of explosive data traffic, ultradense base station (BS deployment in heterogeneous networks (HetNets as a key technique in 5G has been proposed. However, with the increment of BSs, the total energy consumption will also increase. So, the energy efficiency (EE has become a focal point in ultradense HetNets. In this paper, we take the area spectral efficiency (ASE into consideration and focus on the tradeoff between the ASE and EE in an ultradense HetNet. The distributions of BSs in the two-tier ultradense HetNet are modeled by two independent Poisson point processes (PPPs and the expressions of ASE and EE are derived by using the stochastic geometry tool. The tradeoff between the ASE and EE is formulated as a constrained optimization problem in which the EE is maximized under the ASE constraint, through optimizing the BS densities. It is difficult to solve the optimization problem analytically, because the closed-form expressions of ASE and EE are not easily obtained. Therefore, simulations are conducted to find optimal BS densities.

Evaluating the Life Cycle Environmental Benefits and Trade-Offs of Water Reuse Systems for Net-Zero Buildings.

Science.gov (United States)

Hasik, Vaclav; Anderson, Naomi E; Collinge, William O; Thiel, Cassandra L; Khanna, Vikas; Wirick, Jason; Piacentini, Richard; Landis, Amy E; Bilec, Melissa M

2017-02-07

Aging water infrastructure and increased water scarcity have resulted in higher interest in water reuse and decentralization. Rating systems for high-performance buildings implicitly promote the use of building-scale, decentralized water supply and treatment technologies. It is important to recognize the potential benefits and trade-offs of decentralized and centralized water systems in the context of high-performance buildings. For this reason and to fill a gap in the current literature, we completed a life cycle assessment (LCA) of the decentralized water system of a high-performance, net-zero energy, net-zero water building (NZB) that received multiple green building certifications and compared the results with two modeled buildings (conventional and water efficient) using centralized water systems. We investigated the NZB's impacts over varying lifetimes, conducted a break-even analysis, and included Monte Carlo uncertainty analysis. The results show that, although the NZB performs better in most categories than the conventional building, the water efficient building generally outperforms the NZB. The lifetime of the NZB, septic tank aeration, and use of solar energy have been found to be important factors in the NZB's impacts. While these findings are specific to the case study building, location, and treatment technologies, the framework for comparison of water and wastewater impacts of various buildings can be applied during building design to aid decision making. As we design and operate high-performance buildings, the potential trade-offs of advanced decentralized water treatment systems should be considered.

The Rise of Complexity in Flood Forecasting: Opportunities, Challenges and Tradeoffs

Science.gov (United States)

Wood, A. W.; Clark, M. P.; Nijssen, B.

2017-12-01

Operational flood forecasting is currently undergoing a major transformation. Most national flood forecasting services have relied for decades on lumped, highly calibrated conceptual hydrological models running on local office computing resources, providing deterministic streamflow predictions at gauged river locations that are important to stakeholders and emergency managers. A variety of recent technological advances now make it possible to run complex, high-to-hyper-resolution models for operational hydrologic prediction over large domains, and the US National Weather Service is now attempting to use hyper-resolution models to create new forecast services and products. Yet other `increased-complexity' forecasting strategies also exist that pursue different tradeoffs between model complexity (i.e., spatial resolution, physics) and streamflow forecast system objectives. There is currently a pressing need for a greater understanding in the hydrology community of the opportunities, challenges and tradeoffs associated with these different forecasting approaches, and for a greater participation by the hydrology community in evaluating, guiding and implementing these approaches. Intermediate-resolution forecast systems, for instance, use distributed land surface model (LSM) physics but retain the agility to deploy ensemble methods (including hydrologic data assimilation and hindcast-based post-processing). Fully coupled numerical weather prediction (NWP) systems, another example, use still coarser LSMs to produce ensemble streamflow predictions either at the model scale or after sub-grid scale runoff routing. Based on the direct experience of the authors and colleagues in research and operational forecasting, this presentation describes examples of different streamflow forecast paradigms, from the traditional to the recent hyper-resolution, to illustrate the range of choices facing forecast system developers. We also discuss the degree to which the strengths and

Near-term hybrid vehicle program, phase 1. Appendix B: Design trade-off studies report. Volume 2: Supplement to design trade-off studies

Science.gov (United States)

1979-01-01

Results of studies leading to the preliminary design of a hybrid passenger vehicle which is projected to have the maximum potential for reducing petroleum consumption in the near term are presented. Heat engine/electric hybrid vehicle tradeoffs, assessment of battery power source, and weight and cost analysis of key components are among the topics covered. Performance of auxiliary equipment, such as power steering, power brakes, air conditioning, lighting and electrical accessories, heating and ventilation is discussed along with the selection of preferred passenger compartment heating procedure for the hybrid vehicle. Waste heat from the engine, thermal energy storage, and an auxiliary burner are among the approaches considered.

On the Cost-vs-Quality Tradeoff in Make-or-Buy Decisions

OpenAIRE

Andersson, Fredrik

2010-01-01

The make-or-buy decision is analyzed in a simple two-task principal-agent model. There is a cost-saving/quality tradeoff in effort provision. The principal faces a dichotomous choice between weak ("make") and strong ("buy") cost-saving incentives for the agent; the dichotomy is due to an incomplete-contracting limitation necessitating that one party be residual claimant. Choosing "buy" rather than "make" leads to higher cost-saving effort and -- in a plausible "main case" -- to lower quality ...

Market Suitability and Performance Tradeoffs Offered by Commercial Wind Turbines across Differing Wind Regimes

Directory of Open Access Journals (Sweden)

Souma Chowdhury

2016-05-01

Full Text Available The suitability of turbine configurations to different wind resources has been traditionally restricted to considering turbines operating as standalone entities. In this paper, a framework is thus developed to investigate turbine suitability in terms of the minimum cost of energy offered when operating as a group of optimally-micro-sited turbines. The four major steps include: (i characterizing the geographical variation of wind regimes in the onshore U.S. market; (ii determining the best performing turbines for different wind regimes through wind farm layout optimization; (iii developing a metric to quantify the expected market suitability of available turbine configurations; and (iv exploring the best tradeoffs between the cost and capacity factor yielded by these turbines. One hundred thirty one types of commercial turbines offered by major global manufacturers in 2012 are considered for selection. It is found that, in general, higher rated power turbines with medium tower heights are the most favored. Interestingly, further analysis showed that “rotor diameter/hub height” ratios greater than 1.1 are the least attractive for any of the wind classes. It is also observed that although the “cost-capacity factor” tradeoff curve expectedly shifted towards higher capacity factors with increasing wind class, the trend of the tradeoff curve remained practically similar.

Laboratory evolution reveals regulatory and metabolic trade-offs of glycerol utilization in Saccharomyces cerevisiae

DEFF Research Database (Denmark)

Strucko, Tomas; Zirngibl, Katharina; Pereira, Filipa

2018-01-01

osmotolerance. In the other lineages, we find that only three mutations cause the improved phenotype. One of these contributes counter-intuitively by decoupling the TCA cycle from oxidative phosphorylation, and thereby hampers ethanol utilization. Transcriptomics, proteomics and metabolomics analysis of the re...... pathway can remain unexploited due to fitness trade-offs in other, ecologically important, traits....

Quantum circuit implementation of the optimal information-disturbance tradeoff of maximally entangled states

International Nuclear Information System (INIS)

Zhang ShengLi; Zou Xubo; Li Ke; Jin Chenhui; Guo Guangcan

2008-01-01

We give a direct derivation for the information-disturbance tradeoff in estimating a maximally entangled state, which was first obtained by Sacchi (2006 Phys. Rev. Lett. 96 220502) in terms of the covariant positive operator valued measurement (POVM) and Jamiolkowski's isomorphism. We find that, the Cauchy-Schwarz inequality, which is one of the most powerful tools in deriving the tradeoff for a single-particle pure state still plays a key role in the case of the maximal entanglement estimation. Our result shows that the inequality becomes equality when the optimal tradeoff is achieved. Moreover, we demonstrate that such a tradeoff is physically achievable with a quantum circuit that only involves single- and two-particle logic gates and single-particle measurements

Experimental manipulation reveals a trade-off between weapons and testes.

Science.gov (United States)

Somjee, U; Miller, C W; Tatarnic, N J; Simmons, L W

2018-01-01

Theory predicts a trade-off between sexually selected weapons used to secure mates and post-copulatory traits used to maximize fertilization success. However, individuals that have a greater capacity to acquire resources from the environment may invest more in both pre- and post-copulatory traits, and trade-offs may not be readily apparent. Here, we manipulate the phenotype of developing individuals to examine allocation trade-offs between weapons and testes in Mictis profana (Hemiptera: Coreidae), a species where the hind legs are sexually selected weapons used in contests over access to females. We experimentally prevented males from developing weapons by inducing them to autotomize their hind legs before the final moult to adulthood. We compared trait expression in this group to males where autotomy was induced in the mid-legs, which are presumably not under sexual selection to the same extent. We found males without weapons invested proportionally more in testes mass than those with their mid-legs removed. Males that developed to adulthood without weapons did not differ from the mid-leg removal group in other traits potentially under precopulatory sexual selection, other post-copulatory traits or naturally selected traits. In addition, a sample of adult males from the same population in the wild revealed a positive correlation between investment in testes and weapons. Our study presents a critical contribution to a growing body of literature suggesting the allocation of resources to pre- and post-copulatory sexual traits is influenced by a resource allocation trade-off and that this trade-off may only be revealed with experimental manipulation. © 2017 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2017 European Society For Evolutionary Biology.

"Entrepreneurship policy: Trade-offs and impact in the EU"

DEFF Research Database (Denmark)

Murdock, Karen

2012-01-01

Based on the notion that trade-offs in public policies form the basis of the separation of managed and entrepreneurial economies; this paper investigates the impact of policy on actual entrepreneurship activity in these two categories of economies. Using data from 19 European Union member countries......, the impact that policy trade-offs in the goal, target, location and system of finance have on entrepreneurship activity is measured using ordinary least squares regression. The results indicate that while business regulation negatively impact entrepreneurship activity, the location of policy does not show...

Teori Pecking Order dan Trade-Off dalam Analisis Struktur Modal di Bursa Efek Indonesia

Directory of Open Access Journals (Sweden)

D Agus Harjito

2014-06-01

Full Text Available AbstractThis study aims to test the pecking order theory and trade-off theory of capital structure in the analysis of the Indonesia Stock Exchange. Pecking order theory is represented by the variable profitability and growth, while the variables volatility of earnings, tangibility of assets and the size represents a trade-off theory. The company's goal is prosperity of shareholder value. To achieve these objectives the company needs funds from internal sources and external sources. Internal sources in the form of retained earnings, while the external sources of debt and shareholders' approval in the pecking order theory. This study uses the data of financial ratios of the firms during the period 2000-2010. To analyze the data, this study uses a multiple regression with the dependent variable is the debt ratio, while profitability, growth, volatility of earnings, tangibility of assets and size as independent variables. The results show that asset structure and company size has a positive and significant impact on capital structure, while profitability has a negative effect on debt ratios. But company's growth rate has not relationship with the debt ratio or capital structure. Simultaneously, the all independent variables affect capital structure significantly.Keywords: pecking order, trade-off, capital structure, debt rasioAbstrakPenelitian ini bertujuan untuk menguji teori pecking order dan teori trade-off dalam analisis struktur modal di Bursa Efek Indonesia. Teori pecking order diwakili oleh variabel profitability dan growth, sementara variabel-variabel volatility of earnings, tangibility of assets dan size mewakili teori trade-off. Tujuan perusahaan adalah memakmurkan nilai pemegang saham. Untuk mencapai tujuan tersebut perusahaan membutuhkan dana yang diperoleh dari sumber internal dan sumber eksternal. Sumber internal berupa laba ditahan, sedangkan sumber eksternal berupa hutang dan saham sebagaimana dijelaskan dalam teori pecking order

Fitness tradeoffs of antibiotic resistance in extra-intestinal pathogenic Escherichia coli.

Science.gov (United States)

Basra, Prabh; Alsaadi, Ahlam; Bernal-Astrain, Gabriel; O'Sullivan, Michael Liam; Hazlett, Bryn; Clarke, Leah Marie; Schoenrock, Andrew; Pitre, Sylvain; Wong, Alex

2018-02-07

Evolutionary trade-offs occur when selection on one trait has detrimental effects on other traits. In pathogenic microbes, it has been hypothesized that antibiotic resistance trades off with fitness in the absence of antibiotic. While studies of single resistance mutations support this hypothesis, it is unclear whether trade-offs are maintained over time, due to compensatory evolution and broader effects of genetic background. Here, we leverage natural variation in 39 extra-intestinal clinical isolates of Escherichia coli to assess trade-offs between growth rates and resistance to fluoroquinolone and cephalosporin antibiotics. Whole genome sequencing identifies a broad range of clinically relevant resistance determinants in these strains. We find evidence for a negative correlation between growth rate and antibiotic resistance, consistent with a persistent trade-off between resistance and growth. However, this relationship is sometimes weak, and depends on the environment in which growth rates are measured. Using in vitro selection experiments, we find that compensatory evolution in one environment does not guarantee compensation in other environments. Thus, even in the face of compensatory evolution and other genetic background effects, resistance may be broadly costly, supporting the use of drug restriction protocols to limit the spread of resistance. Furthermore, our study demonstrates the power of using natural variation to study evolutionary trade-offs in microbes. © The Author(s) 2018. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Linking environment-productivity trade-offs and correlated uncertainties: Greenhouse gas emissions and crop productivity in paddy rice production systems

International Nuclear Information System (INIS)

Hayashi, Kiyotada; Nagumo, Yoshifumi; Domoto, Akiko

2016-01-01

In comparative life cycle assessments of agricultural production systems, analyses of both the trade-offs between environmental impacts and crop productivity and of the uncertainties specific to agriculture such as fluctuations in greenhouse gas (GHG) emissions and crop yields are crucial. However, these two issues are usually analyzed separately. In this paper, we present a framework to link trade-off and uncertainty analyses; correlated uncertainties are integrated into environment-productivity trade-off analyses. We compared three rice production systems in Japan: a system using a pelletized, nitrogen-concentrated organic fertilizer made from poultry manure using closed-air composting techniques (high-N system), a system using a conventional organic fertilizer made from poultry manure using open-air composting techniques (low-N system), and a system using a chemical compound fertilizer (conventional system). We focused on two important sources of uncertainties in paddy rice cultivation—methane emissions from paddy fields and crop yields. We found trade-offs between the conventional and high-N systems and the low-N system and the existence of positively correlated uncertainties in the conventional and high-N systems. We concluded that our framework is effective in recommending the high-N system compared with the low-N system, although the performance of the former is almost the same as the conventional system. - Highlights: • Correlated uncertainties were integrated into environment-productivity trade-offs. • Life cycle GHG emissions and crop yields were analyzed using field and survey data. • Three rice production systems using chemical or organic fertilizers were compared. • There were portfolio (insurance) effects in matured technologies. • Analysis of trade-offs and correlated uncertainties will be useful for decisions.

Linking environment-productivity trade-offs and correlated uncertainties: Greenhouse gas emissions and crop productivity in paddy rice production systems

Energy Technology Data Exchange (ETDEWEB)

Hayashi, Kiyotada, E-mail: hayashi@affrc.go.jp [Institute for Agro-Environmental Sciences, National Agriculture and Food Research Organization, 3-1-3 Kannondai, Tsukuba, Ibaraki 305-8604 (Japan); Nagumo, Yoshifumi [Crop Research Center, Niigata Agricultural Research Institute, 857 Nagakura-machi, Nagaoka, Niigata 940-0826 (Japan); Domoto, Akiko [Mie Prefecture Agricultural Research Institute, 530 Kawakita-cho, Ureshino, Matsusaka, Mie 515-2316 (Japan)

2016-11-15

In comparative life cycle assessments of agricultural production systems, analyses of both the trade-offs between environmental impacts and crop productivity and of the uncertainties specific to agriculture such as fluctuations in greenhouse gas (GHG) emissions and crop yields are crucial. However, these two issues are usually analyzed separately. In this paper, we present a framework to link trade-off and uncertainty analyses; correlated uncertainties are integrated into environment-productivity trade-off analyses. We compared three rice production systems in Japan: a system using a pelletized, nitrogen-concentrated organic fertilizer made from poultry manure using closed-air composting techniques (high-N system), a system using a conventional organic fertilizer made from poultry manure using open-air composting techniques (low-N system), and a system using a chemical compound fertilizer (conventional system). We focused on two important sources of uncertainties in paddy rice cultivation—methane emissions from paddy fields and crop yields. We found trade-offs between the conventional and high-N systems and the low-N system and the existence of positively correlated uncertainties in the conventional and high-N systems. We concluded that our framework is effective in recommending the high-N system compared with the low-N system, although the performance of the former is almost the same as the conventional system. - Highlights: • Correlated uncertainties were integrated into environment-productivity trade-offs. • Life cycle GHG emissions and crop yields were analyzed using field and survey data. • Three rice production systems using chemical or organic fertilizers were compared. • There were portfolio (insurance) effects in matured technologies. • Analysis of trade-offs and correlated uncertainties will be useful for decisions.

Models and statistical analysis of organic micropollutants in groundwater-based drinking water resources

DEFF Research Database (Denmark)

Malaguerra, Flavio

The access to safe drinking water is essential for the well being of the population. The spread of micropollutant contamination jeopardise many freshwater reservoirs, and is a serious threat for human health, especially because of its long-term effects. To asses the threat of contamination, models...... to model. The identification of dominant processes is an essential step in the understanding of system behaviour, because it enables the development of simplified models that can approximate the fate of contaminants with the best trade-off between model complexity and reliability of results. In this thesis......, global sensitivity analysis techniques are used to assess detailed models in order to identify the main processes involved in the degradation of chlorinated solvents in the subsurface, and in the transport of pesticides from surface water into nearby wells in confined aquifers. Statistical techniques...

Optimal trade-offs between energy efficiency improvements and additional renewable energy supply: A review of international experiences

DEFF Research Database (Denmark)

Baldini, Mattia; Klinge Jacobsen, Henrik

2016-01-01

the improvements made in the energy saving field. Indeed, little attention has been paid to implement energy efficiency measures, which has resulted in scenarios where expedients for a wise use of energy (e.g. energy savings and renewables share) are unbalanced. The aim of this paper is to review and evaluate...... international experiences on finding the optimal trade-off between efficiency improvements and additional renewable energy supply. A critical review of each technique, focusing on purposes, methodology and outcomes, is provided along with a review of tools adopted for the analyses. The models are categorized...... trade-off between renewables and energy efficiency measures in energy-systems under different objectives....

A stochastic multicriteria model for evidence-based decision making in drug benefit-risk analysis.

Science.gov (United States)

Tervonen, Tommi; van Valkenhoef, Gert; Buskens, Erik; Hillege, Hans L; Postmus, Douwe

2011-05-30

Drug benefit-risk (BR) analysis is based on firm clinical evidence regarding various safety and efficacy outcomes. In this paper, we propose a new and more formal approach for constructing a supporting multi-criteria model that fully takes into account the evidence on efficacy and adverse drug reactions. Our approach is based on the stochastic multi-criteria acceptability analysis methodology, which allows us to compute the typical value judgments that support a decision, to quantify decision uncertainty, and to compute a comprehensive BR profile. We construct a multi-criteria model for the therapeutic group of second-generation antidepressants. We assess fluoxetine and venlafaxine together with placebo according to incidence of treatment response and three common adverse drug reactions by using data from a published study. Our model shows that there are clear trade-offs among the treatment alternatives. Copyright © 2011 John Wiley & Sons, Ltd.

A Novel Piezoresistive Accelerometer with SPBs to Improve the Tradeoff between the Sensitivity and the Resonant Frequency.

Science.gov (United States)

Xu, Yu; Zhao, Libo; Jiang, Zhuangde; Ding, Jianjun; Peng, Niancai; Zhao, Yulong

2016-02-06

For improving the tradeoff between the sensitivity and the resonant frequency of piezoresistive accelerometers, the dependency between the stress of the piezoresistor and the displacement of the structure is taken into consideration in this paper. In order to weaken the dependency, a novel structure with suspended piezoresistive beams (SPBs) is designed, and a theoretical model is established for calculating the location of SPBs, the stress of SPBs and the resonant frequency of the whole structure. Finite element method (FEM) simulations, comparative simulations and experiments are carried out to verify the good agreement with the theoretical model. It is demonstrated that increasing the sensitivity greatly without sacrificing the resonant frequency is possible in the piezoresistive accelerometer design. Therefore, the proposed structure with SPBs is potentially a novel option for improving the tradeoff between the sensitivity and the resonant frequency of piezoresistive accelerometers.

Incentivising flood risk adaptation through risk based insurance premiums : Trade-offs between affordability and risk reduction

NARCIS (Netherlands)

Hudson, Paul F.; Botzen, W.J.W.; Feyen, L.; Aerts, Jeroen C.J.H.

2016-01-01

The financial incentives offered by the risk-based pricing of insurance can stimulate policyholder adaptation to flood risk while potentially conflicting with affordability. We examine the trade-off between risk reduction and affordability in a model of public-private flood insurance in France and

Incentivising flood risk adaptation through ris based insurance premiums: trade-offs between affordability and risk reduction

NARCIS (Netherlands)

Hudson, P.G.M.B.; Botzen, W.J.W.; Feyen, L.; Aerts, J.C.J.H.

2016-01-01

The financial incentives offered by the risk-based pricing of insurance can stimulate policyholder adaptation to flood risk while potentially conflicting with affordability. We examine the trade-off between risk reduction and affordability in a model of public-private flood insurance in France and

Causal Rasch models

Directory of Open Access Journals (Sweden)

A. Jackson Stenner

2013-08-01

Full Text Available Rasch’s unidimensional models for measurement show how to connect object measures (e.g., reader abilities, measurement mechanisms (e.g., machine-generated cloze reading items, and observational outcomes (e.g., counts correct on reading instruments. Substantive theory shows what interventions or manipulations to the measurement mechanism can be traded off against a change to the object measure to hold the observed outcome constant. A Rasch model integrated with a substantive theory dictates the form and substance of permissible interventions. Rasch analysis, absent construct theory and an associated specification equation, is a black box in which understanding may be more illusory than not. Finally, the quantitative hypothesis can be tested by comparing theory-based trade-off relations with observed trade-off relations. Only quantitative variables (as measured support such trade-offs. Note that to test the quantitative hypothesis requires more than manipulation of the algebraic equivalencies in the Rasch model or descriptively fitting data to the model. A causal Rasch model involves experimental intervention/manipulation on either reader ability or text complexity or a conjoint intervention on both simultaneously to yield a successful prediction of the resultant observed outcome (count correct. We conjecture that when this type of manipulation is introduced for individual reader text encounters and model predictions are consistent with observations, the quantitative hypothesis is sustained.

Causal Rasch models.

Science.gov (United States)

Stenner, A Jackson; Fisher, William P; Stone, Mark H; Burdick, Donald S

2013-01-01

Rasch's unidimensional models for measurement show how to connect object measures (e.g., reader abilities), measurement mechanisms (e.g., machine-generated cloze reading items), and observational outcomes (e.g., counts correct on reading instruments). Substantive theory shows what interventions or manipulations to the measurement mechanism can be traded off against a change to the object measure to hold the observed outcome constant. A Rasch model integrated with a substantive theory dictates the form and substance of permissible interventions. Rasch analysis, absent construct theory and an associated specification equation, is a black box in which understanding may be more illusory than not. Finally, the quantitative hypothesis can be tested by comparing theory-based trade-off relations with observed trade-off relations. Only quantitative variables (as measured) support such trade-offs. Note that to test the quantitative hypothesis requires more than manipulation of the algebraic equivalencies in the Rasch model or descriptively fitting data to the model. A causal Rasch model involves experimental intervention/manipulation on either reader ability or text complexity or a conjoint intervention on both simultaneously to yield a successful prediction of the resultant observed outcome (count correct). We conjecture that when this type of manipulation is introduced for individual reader text encounters and model predictions are consistent with observations, the quantitative hypothesis is sustained.

Causal Rasch models

Science.gov (United States)

Stenner, A. Jackson; Fisher, William P.; Stone, Mark H.; Burdick, Donald S.

2013-01-01

Rasch's unidimensional models for measurement show how to connect object measures (e.g., reader abilities), measurement mechanisms (e.g., machine-generated cloze reading items), and observational outcomes (e.g., counts correct on reading instruments). Substantive theory shows what interventions or manipulations to the measurement mechanism can be traded off against a change to the object measure to hold the observed outcome constant. A Rasch model integrated with a substantive theory dictates the form and substance of permissible interventions. Rasch analysis, absent construct theory and an associated specification equation, is a black box in which understanding may be more illusory than not. Finally, the quantitative hypothesis can be tested by comparing theory-based trade-off relations with observed trade-off relations. Only quantitative variables (as measured) support such trade-offs. Note that to test the quantitative hypothesis requires more than manipulation of the algebraic equivalencies in the Rasch model or descriptively fitting data to the model. A causal Rasch model involves experimental intervention/manipulation on either reader ability or text complexity or a conjoint intervention on both simultaneously to yield a successful prediction of the resultant observed outcome (count correct). We conjecture that when this type of manipulation is introduced for individual reader text encounters and model predictions are consistent with observations, the quantitative hypothesis is sustained. PMID:23986726

Condition-Dependent Trade-Off Between Weapon Size and Immunity in Males of the European Earwig.

Science.gov (United States)

Körner, Maximilian; Vogelweith, Fanny; Foitzik, Susanne; Meunier, Joël

2017-08-11

Investigating the expression of trade-offs between key life-history functions is central to our understanding of how these functions evolved and are maintained. However, detecting trade-offs can be challenging due to variation in resource availability, which masks trade-offs at the population level. Here, we investigated in the European earwig Forficula auricularia whether (1) weapon size trades off with three key immune parameters - hemocyte concentration, phenoloxidase and prophenoloxidase activity - and whether (2) expression and strength of these trade-offs depend on male body condition (body size) and/or change after an immune challenge. Our results partially confirmed condition dependent trade-offs between weapon size and immunity in male earwigs. Specifically, we found that after an immune challenge, weapon size trades off with hemocyte concentrations in low-condition, but not in good-condition males. Contrastingly, weapon size was independent of pre-challenge hemocyte concentration. We also found no trade-off between weapon size and phenoloxidase activity, independent of body condition and immune challenge. Overall, our study reveals that trade-offs with sexual traits may weaken or disappear in good-condition individuals. Given the importance of weapon size for male reproductive success, our results highlight how low-condition individuals may employ alternative life-history investment strategies to cope with resource limitation.

Optimal Design and Tradeoff Analysis of Planar Transformer in High-Power DC–DC Converters

DEFF Research Database (Denmark)

Ouyang, Ziwei; Thomsen, Ole Cornelius; Andersen, Michael A. E.

2012-01-01

The trend toward high power density, high operating frequency, and low profile in power converters has exposed a number of limitations in the use of conventional wire-wound magnetic component structures. A planar magnetic is a low-profile transformer or inductor utilizing planar windings, instead...... of the traditional windings made of Cu wires. In this paper, the most important factors for planar transformer (PT) design including winding loss, core loss, leakage inductance, and stray capacitance have individually been investigated. The tradeoffs among these factors have to be analyzed in order to achieve...

Disguising quantum channels by mixing and channel distance trade-off

International Nuclear Information System (INIS)

Fung, Chi-Hang Fred; Chau, H F

2014-01-01

We consider the reverse problem of the distinguishability of two quantum channels, which we call the disguising problem. Given two quantum channels, the goal here is to make the two channels identical by mixing with some other channels with minimal mixing probabilities. This quantifies how much one channel can disguise as the other. In addition, the possibility to trade-off between the two mixing probabilities allows one channel to be more preserved (less mixed) at the expense of the other. We derive lower- and upper-bounds of the trade-off curve and apply them to a few example channels. Optimal trade-off is obtained in one example. We relate the disguising problem and the distinguishability problem by showing that the former can lower and upper bound the diamond norm. We also show that the disguising problem gives an upper-bound on the key generation rate in quantum cryptography. (paper)

Integrated Adaptive Scenarios for Ariculture: Synergies and Tradeoffs.

Science.gov (United States)

Malek, K.; Rajagopalan, K.; Adam, J. C.; Brady, M.; Stockle, C.; Liu, M.; Kruger, C. E.

2017-12-01

A wide variety of factors can drive adaptation of the agricultural production sector in response to climate change. Warming and increased growing season length can lead to adoption of newer plant varieties as well as increases in double cropping systems. Changes in expectations of drought frequency or economic factors could lead to adoption of new technology (such as irrigation technology or water trading systems) or crop choices with a view of reducing farm-level risk, and these choices can result in unintended system wide effects. These are all examples of producer adaptation decisions made with a long-term (multiple decades) view. In addition, producers respond to short-term (current year) shocks - such as drought events - through management strategies that include deficit irrigation, fallowing, nutrient management, and engaging in water trading. The effects of these short- and long-term decisions are not independent, and can drive or be driven by the other. For example, investment in new irrigation systems (long-term) can be driven by expectations of short-term crop productivity losses in drought years. Similarly, the capacity to manage for short-term shocks will depend on crop type and variety as well as adopted irrigation technologies. Our overarching objective is to understand the synergies and tradeoffs that exist when combining three potential long-term adaptation strategies and two short-term adaptation strategies, with a view of understanding the synergies and tradeoffs. We apply the integrated crop-hydrology modeling framework VIC-CropSyst, along with the water management module Yakima RiverWare to address these questions over our test area, the Yakima River basin. We consider adoption of a) more efficient irrigation technologies, slower growing crop varieties, and increased prevalence of double cropping systems as long-term adaptation strategies; and b) fallowing and deficit irrigation as short-term responses to droughts. We evaluate the individual and

Tradeoffs around crop residue biomass in smallholder crop-livestock systems - What's next?

NARCIS (Netherlands)

Tittonell, P.A.; Gérard, B.; Erenstein, O.

2015-01-01

Much has been written on the tradeoffs that smallholder farmers face when having to allocate their biomass resources among competing objectives such as feed, fuel, mulch, compost or the market. This paper summarises yet a new body of evidence from 10 studies on tradeoffs in the allocation of cereal

Insights from life history theory for an explicit treatment of trade-offs in conservation biology.

Science.gov (United States)

Charpentier, Anne

2015-06-01

As economic and social contexts become more embedded within biodiversity conservation, it becomes obvious that resources are a limiting factor in conservation. This recognition is leading conservation scientists and practitioners to increasingly frame conservation decisions as trade-offs between conflicting societal objectives. However, this framing is all too often done in an intuitive way, rather than by addressing trade-offs explicitly. In contrast, the concept of trade-off is a keystone in evolutionary biology, where it has been investigated extensively. I argue that insights from evolutionary theory can provide methodological and theoretical support to evaluating and quantifying trade-offs in biodiversity conservation. I reviewed the diverse ways in which trade-offs have emerged within the context of conservation and how advances from evolutionary theory can help avoid the main pitfalls of an implicit approach. When studying both evolutionary trade-offs (e.g., reproduction vs. survival) and conservation trade-offs (e.g., biodiversity conservation vs. agriculture), it is crucial to correctly identify the limiting resource, hold constant the amount of this resource when comparing different scenarios, and choose appropriate metrics to quantify the extent to which the objectives have been achieved. Insights from studies in evolutionary theory also reveal how an inadequate selection of conservation solutions may result from considering suboptimal rather than optional solutions when examining whether a trade-off exits between 2 objectives. Furthermore, the shape of a trade-off curve (i.e., whether the relationship between 2 objectives follows a concave, convex, or linear form) is known to affect crucially the definition of optimal solutions in evolutionary biology and very likely affects decisions in biodiversity conservation planning too. This interface between evolutionary biology and biodiversity conservation can therefore provide methodological guidance to

Understanding tradeoffs in the supplier selection process : The role of flexibility, delivery, and value-added services/support

NARCIS (Netherlands)

Rhee, van der B.; Verma, R.; Plaschka, G.

2009-01-01

In this study, we present, based on econometric choice modeling framework, how manufacturing managers/executives trade-off between cost, delivery, flexibility, and service features in the supplier selection process for commodity raw materials, given acceptable quality. Empirical data for this study

Environmental trade-offs of tunnels vs cut-and-cover subways

Science.gov (United States)

Walton, M.

1978-01-01

Heavy construction projects in cities entail two kinds of cost - internal cost, which can be defined in terms of payments from one set of parties to another, and external cost, which is the cost borne by the community at large as the result of disutilities entailed in construction and operation. Environmental trade-offs involve external costs, which are commonly difficult to measure. Cut-and-cover subway construction probably entails higher external and internal cost than deep tunnel construction in many urban geological environments, but uncertainty concerning the costs and environmental trade-offs of tunneling leads to limited and timid use of tunneling by American designers. Thus uncertainty becomes a major trade-off which works against tunneling. The reverse is true in Sweden after nearly 30 years of subway construction. Econometric methods for measuring external costs exist in principle, but are limited in application. Economic theory based on market pressure does not address the real problem of urban environmental trade-offs. Nevertheless, the problem of uncertainty can be addressed by comparative studies of estimated and as-built costs of cut-and-cover vs tunnel projects and a review of environmental issues associated with such construction. Such a study would benefit the underground construction industry and the design of transportation systems. It would also help solve an aspect of the urban problem. ?? 1978.

Analysis of radiology business models.

Science.gov (United States)

Enzmann, Dieter R; Schomer, Donald F

2013-03-01

As health care moves to value orientation, radiology's traditional business model faces challenges to adapt. The authors describe a strategic value framework that radiology practices can use to best position themselves in their environments. This simplified construct encourages practices to define their dominant value propositions. There are 3 main value propositions that form a conceptual triangle, whose vertices represent the low-cost provider, the product leader, and the customer intimacy models. Each vertex has been a valid market position, but each demands specific capabilities and trade-offs. The underlying concepts help practices select value propositions they can successfully deliver in their competitive environments. Copyright © 2013 American College of Radiology. Published by Elsevier Inc. All rights reserved.

The trade-off between money and time: A test of the theory of reference-dependent preferences

DEFF Research Database (Denmark)

De Borger, Bruno; Fosgerau, Mogens

2008-01-01

We formulate a model of reference-dependent preferences based on the marginal rate of substitution at the reference-point of a reference-free utility function. Using binary choices on the trade-off between money and travel time, reference-dependence is captured by value functions that are centered...

The role of plant functional trade-offs for biodiversity changes and biome shifts under scenarios of global climatic change

Directory of Open Access Journals (Sweden)

B. Reu

2011-05-01

Full Text Available The global geographic distribution of biodiversity and biomes is determined by species-specific physiological tolerances to climatic constraints. Current vegetation models employ empirical bioclimatic relationships to predict present-day vegetation patterns and to forecast biodiversity changes and biome shifts under climatic change. In this paper, we consider trade-offs in plant functioning and their responses under climatic changes to forecast and explain changes in plant functional richness and shifts in biome geographic distributions.

The Jena Diversity model (JeDi simulates plant survival according to essential plant functional trade-offs, including ecophysiological processes such as water uptake, photosynthesis, allocation, reproduction and phenology. We use JeDi to quantify changes in plant functional richness and biome shifts between present-day and a range of possible future climates from two SRES emission scenarios (A2 and B1 and seven global climate models using metrics of plant functional richness and functional identity.

Our results show (i a significant loss of plant functional richness in the tropics, (ii an increase in plant functional richness at mid and high latitudes, and (iii a pole-ward shift of biomes. While these results are consistent with the findings of empirical approaches, we are able to explain them in terms of the plant functional trade-offs involved in the allocation, metabolic and reproduction strategies of plants. We conclude that general aspects of plant physiological tolerances can be derived from functional trade-offs, which may provide a useful process- and trait-based alternative to bioclimatic relationships. Such a mechanistic approach may be particularly relevant when addressing vegetation responses to climatic changes that encounter novel combinations of climate parameters that do not exist under contemporary climate.

Valuing tradeoffs between agricultural production and ecosystem services in the Heihe River Basin

Science.gov (United States)

Li, Z.; Deng, X.; Wu, F.

2017-12-01

Ecosystem services are faced with multiple stress from complex driving factors, such as climate change and human interventions. The Heihe River Basin (HRB), as the second largest inland river basin in China, is a typical semi-arid and arid region with fragile and sensitive ecological environment. For the past decades, agricultural production activities in the basin has affected ecosystem services in different degrees, leading to complex relations among "water-land-climate-ecology-human", in which hydrological process and water resource management is the key. In this context, managing trade-offs among water uses in the river basin to sustain multiple ecosystem services is crucial for healthy ecosystem and sustainable socioeconomic development. In this study, we analyze the trade-offs between different water uses in agricultural production and key ecosystem services in the HRB by applying production frontier analysis, with the aim to explore the potential for managing them. This method traces out joint production frontiers showing the combinations of ecosystem services and agricultural production that can be generated in a given area, and it deals with the economic problem of the allocation of scarce water resources under presumed objective, which aims to highlight synergies and reduce trade-offs between alternative water uses. Thus, management schemes that targets to both sustain agricultural production and increase the provision of key ecosystem services have to consider not only the technological or biological nature of interrelationships, but also the economic interdependencies among them.

Evolutionary trade-offs in plants mediate the strength of trophic cascades.

Science.gov (United States)

Mooney, Kailen A; Halitschke, Rayko; Kessler, Andre; Agrawal, Anurag A

2010-03-26

Predators determine herbivore and plant biomass via so-called trophic cascades, and the strength of such effects is influenced by ecosystem productivity. To determine whether evolutionary trade-offs among plant traits influence patterns of trophic control, we manipulated predators and soil fertility and measured impacts of a major herbivore (the aphid Aphis nerii) on 16 milkweed species (Asclepias spp.) in a phylogenetic field experiment. Herbivore density was determined by variation in predation and trade-offs between herbivore resistance and plant growth strategy. Neither herbivore density nor predator effects on herbivores predicted the cascading effects of predators on plant biomass. Instead, cascade strength was strongly and positively associated with milkweed response to soil fertility. Accordingly, contemporary patterns of trophic control are driven by evolutionary convergent trade-offs faced by plants.

Trade-offs, co-benefits and safeguards: Current debates on the breadth of REDD+.

NARCIS (Netherlands)

Visseren-Hamakers, I.J.; McDermott, C.; Vijge, M.J.; Cashore, B.

2012-01-01

Fundamental trade-offs exist between different land uses for carbon, livelihoods, economic development, biodiversity, agriculture and energy (especially biofuels). This article analyses the scientific debates on REDD+ trade-offs, co-benefits and safeguards, and shows how the development and expanded

Anticipating and Managing Future Trade-offs and Complementarities between Ecosystem Services

Directory of Open Access Journals (Sweden)

Mark S. Reed

2013-03-01

Full Text Available This paper shows how, with the aid of computer models developed in close collaboration with decision makers and other stakeholders, it is possible to quantify and map how policy decisions are likely to affect multiple ecosystem services in future. In this way, potential trade-offs and complementarities between different ecosystem services can be identified, so that policies can be designed to avoid the worst trade-offs, and where possible, enhance multiple services. The paper brings together evidence from across the Rural Economy and Land Use Programme's Sustainable Uplands project for the first time, with previously unpublished model outputs relating to runoff, agricultural suitability, biomass, heather cover, age, and utility for Red Grouse (Lagopus scotica, grass cover, and accompanying scenario narratives and video. Two contrasting scenarios, based on policies to extensify or intensify land management up to 2030, were developed through a combination of interviews and discussions during site visits with stakeholders, literature review, conceptual modeling, and process-based computer models, using the Dark Peak of the Peak District National Park in the UK as a case study. Where extensification leads to a significant reduction in managed burning and grazing or land abandonment, changes in vegetation type and structure could compromise a range of species that are important for conservation, while compromising provisioning services, amenity value, and increasing wildfire risk. However, where extensification leads to the restoration of peatlands damaged by former intensive management, there would be an increase in carbon sequestration and storage, with a number of cobenefits, which could counter the loss of habitats and species elsewhere in the landscape. In the second scenario, land use and management was significantly intensified to boost UK self-sufficiency in food. This would benefit certain provisioning services but would have negative

Many-objective optimization and visual analytics reveal key trade-offs for London's water supply

Science.gov (United States)

Matrosov, Evgenii S.; Huskova, Ivana; Kasprzyk, Joseph R.; Harou, Julien J.; Lambert, Chris; Reed, Patrick M.

2015-12-01

In this study, we link a water resource management simulator to multi-objective search to reveal the key trade-offs inherent in planning a real-world water resource system. We consider new supplies and demand management (conservation) options while seeking to elucidate the trade-offs between the best portfolios of schemes to satisfy projected water demands. Alternative system designs are evaluated using performance measures that minimize capital and operating costs and energy use while maximizing resilience, engineering and environmental metrics, subject to supply reliability constraints. Our analysis shows many-objective evolutionary optimization coupled with state-of-the art visual analytics can help planners discover more diverse water supply system designs and better understand their inherent trade-offs. The approach is used to explore future water supply options for the Thames water resource system (including London's water supply). New supply options include a new reservoir, water transfers, artificial recharge, wastewater reuse and brackish groundwater desalination. Demand management options include leakage reduction, compulsory metering and seasonal tariffs. The Thames system's Pareto approximate portfolios cluster into distinct groups of water supply options; for example implementing a pipe refurbishment program leads to higher capital costs but greater reliability. This study highlights that traditional least-cost reliability constrained design of water supply systems masks asset combinations whose benefits only become apparent when more planning objectives are considered.

Statistical Multiplexing of Computations in C-RAN with Tradeoffs in Latency and Energy

DEFF Research Database (Denmark)

Kalør, Anders Ellersgaard; Agurto Agurto, Mauricio Ignacio; Pratas, Nuno

2017-01-01

frame duration, then this may result in additional access latency and limit the energy savings. In this paper we investigate the tradeoff by considering two extreme time-scales for the resource multiplexing: (i) long-term, where the computational resources are adapted over periods much larger than...... the access frame durations; (ii) short-term, where the adaption is below the access frame duration.We develop a general C-RAN queuing model that models the access latency and show, for Poisson arrivals, that long-term multiplexing achieves savings comparable to short-term multiplexing, while offering low...

Integrating ecosystem-service tradeoffs into land-use decisions.

Science.gov (United States)

Goldstein, Joshua H; Caldarone, Giorgio; Duarte, Thomas Kaeo; Ennaanay, Driss; Hannahs, Neil; Mendoza, Guillermo; Polasky, Stephen; Wolny, Stacie; Daily, Gretchen C

2012-05-08

Recent high-profile efforts have called for integrating ecosystem-service values into important societal decisions, but there are few demonstrations of this approach in practice. We quantified ecosystem-service values to help the largest private landowner in Hawaii, Kamehameha Schools, design a land-use development plan that balances multiple private and public values on its North Shore land holdings (Island of O'ahu) of ∼10,600 ha. We used the InVEST software tool to evaluate the environmental and financial implications of seven planning scenarios encompassing contrasting land-use combinations including biofuel feedstocks, food crops, forestry, livestock, and residential development. All scenarios had positive financial return relative to the status quo of negative return. However, tradeoffs existed between carbon storage and water quality as well as between environmental improvement and financial return. Based on this analysis and community input, Kamehameha Schools is implementing a plan to support diversified agriculture and forestry. This plan generates a positive financial return ($10.9 million) and improved carbon storage (0.5% increase relative to status quo) with negative relative effects on water quality (15.4% increase in potential nitrogen export relative to status quo). The effects on water quality could be mitigated partially (reduced to a 4.9% increase in potential nitrogen export) by establishing vegetation buffers on agricultural fields. This plan contributes to policy goals for climate change mitigation, food security, and diversifying rural economic opportunities. More broadly, our approach illustrates how information can help guide local land-use decisions that involve tradeoffs between private and public interests.

A Novel Piezoresistive Accelerometer with SPBs to Improve the Tradeoff between the Sensitivity and the Resonant Frequency

Directory of Open Access Journals (Sweden)

Yu Xu

2016-02-01

Full Text Available For improving the tradeoff between the sensitivity and the resonant frequency of piezoresistive accelerometers, the dependency between the stress of the piezoresistor and the displacement of the structure is taken into consideration in this paper. In order to weaken the dependency, a novel structure with suspended piezoresistive beams (SPBs is designed, and a theoretical model is established for calculating the location of SPBs, the stress of SPBs and the resonant frequency of the whole structure. Finite element method (FEM simulations, comparative simulations and experiments are carried out to verify the good agreement with the theoretical model. It is demonstrated that increasing the sensitivity greatly without sacrificing the resonant frequency is possible in the piezoresistive accelerometer design. Therefore, the proposed structure with SPBs is potentially a novel option for improving the tradeoff between the sensitivity and the resonant frequency of piezoresistive accelerometers.

The teaching/research trade-off in law: data from the right tail.

Science.gov (United States)

Ginsburg, Tom; Miles, Thomas J

2015-02-01

There is a long scholarly debate on the trade-off between research and teaching in various fields, but relatively little study of the phenomenon in law. This analysis examines the relationship between the two core academic activities at one particular school, the University of Chicago Law School, which is considered one of the most productive in legal academia. We measure of scholarly productivity with the total number of publications by each professor for each year, and we approximate performance in teaching with course loads and average scores in student evaluations for each course. In OLS regressions, we estimate scholarly output as a function of teaching loads, faculty characteristics, and other controls. We also estimate teaching evaluation scores as a function of scholarly productivity, fixed effects for years and course subject, and faculty characteristics. Net of other factors, we find that, under some specifications, research and teaching are positively correlated. In particular, we find that students' perceptions of teaching quality rises, but at a decreasing rate, with the total amount of scholarship. We also find that certain personal characteristics correlate with productivity. The recent debate on the mission of American law schools has hinged on the assumption that a trade-off exists between teaching and research, and this article's analysis, although limited in various ways, casts some doubt on that assumption. © The Author(s) 2014.

Blue water tradeoffs with ecosystems in a CO2-enriched climate

Science.gov (United States)

Mankin, J. S.; Smerdon, J. E.; Cook, B. I.; Williams, A. P.; Seager, R.

2017-12-01

Present and future freshwater availability and drought risks are physically tied to the competing responses of surface vegetation to increasing CO2, which includes radiative and plant physiological forcing, as well as their consequences for plant phenology, water use efficiency, and CO2 fertilization. Because Earth system models (ESMs) have increased their sophistication in representing the coupling among biogeochemical and biogeophysical processes at the land surface, projected linkages among ecosystem responses to CO2 and blue water (runoff) can be explored. A detailed analysis of the Western US demonstrates that CO2- and radiatively-induced vegetation growth drives projected decreases in soil moisture and runoff in the NCAR CESM LENS, creating a curious pattern of colocated 'greening' and 'drying.' Here we explore these responses at the global-scale and the consequences of such vegetation-driven drying on blue water availability for people. We present a simple metric that quantifies the tradeoff that occurs between ecosystems and blue water and link their occurrence to changes in daily-scale precipitation extremes, plant functional types, and changes in leaf areas. These results have implications for blue water availability for people and raise important questions about model representations of vegetation-water responses to high CO2.

Measuring service quality trade-offs in Asian distribution channels: A multi-layer perspective

NARCIS (Netherlands)

Wetzels, M.G.M.; Ruyter, de J.C.; Lemmink, J.G.A.M.

2000-01-01

In international marketing channels customer service has become an important factor in supplier and purchase decisions. In evaluating supplier performance several trade-offs are taken into account by actors operating at various channel levels. These are trade-offs among customer service elements and

Life history trade-offs imposed by dragline use in two money spiders

OpenAIRE

Bonte, Dries; Verduyn, Lieselot; Braeckman, Bart

2016-01-01

Trade-offs among life history traits are central to understanding the limits of adaptations to stress. In animals, virtually all decisions taken during life are expected to have downstream consequences. To what degree rare, but energy-demanding, decisions carry over to individual performance is rarely studied in arthropods. We used spiders as a model system to test how single investments in silk use - for dispersal or predator escape - affect individual performance. Silk produced for safe lin...

Growth tradeoffs associated with thermotolerant symbionts in the coral Pocillopora damicornis are lost in warmer oceans

Science.gov (United States)

Cunning, R.; Gillette, P.; Capo, T.; Galvez, K.; Baker, A. C.

2015-03-01

The growth and survival of reef corals are influenced by their symbiotic algal partners ( Symbiodinium spp.), which may be flexible in space and time. Tradeoffs among partnerships exist such that corals with thermotolerant symbionts (e.g., clade D) resist bleaching but grow more slowly, making the long-term ecosystem-level impacts of different host-symbiont associations uncertain. However, much of this uncertainty is due to limited data regarding these tradeoffs and particularly how they are mediated by the environment. To address this knowledge gap, we measured growth and survival of Pocillopora damicornis with thermally sensitive (clade C) or tolerant (clade D) symbionts at three temperatures over 18-55 weeks. Warming reduced coral growth overall, but altered the tradeoffs associated with symbiont type. While clade D corals grew 35-40 % slower than clade C corals at cooler temperatures (26 °C), warming of 1.5-3 °C reduced and eliminated this growth disadvantage. These results suggest that although warmer oceans will negatively impact corals, clade D may enhance survival at no cost to growth relative to clade C. Understanding these genotype-environment interactions can help improve modeling efforts and conservation strategies for reefs under global climate change.

Modeling and Analysis of Inter-Vehicle Communication: A Stochastic Geometry Approach

KAUST Repository

Farooq, Muhammad Junaid

2015-05-01

Vehicular communication is the enabling technology for the development of the intelligent transportation systems (ITS), which aims to improve the efficiency and safety of transportation. It can be used for a variety of useful applications such as adaptive traffic control, coordinated braking, emergency messaging, peer-to-peer networking for infotainment services and automatic toll collection etc... Accurate yet simple models for vehicular networks are required in order to understand and optimize their operation. For reliable communication between vehicles, the spectrum access is coordinated via carrier sense multiple access (CSMA) protocol. Existing models either use a simplified network abstraction and access control scheme for analysis or depend on simulation studies. Therefore it is important to develop an analytical model for CSMA coordinated communication between vehicles. In the first part of the thesis, stochastic geometry is exploited to develop a modeling framework for CSMA coordinated inter-vehicle communication (IVC) in a multi-lane highway scenario. The performance of IVC is studied in multi-lane highways taking into account the inter-lane separations and the number of traffic lanes and it is shown that for wide multi-lane highways, the line abstraction model that is widely used in literature loses accuracy and hence the analysis is not reliable. Since the analysis of CSMA in the vehicular setting makes the analysis intractable, an aggressive interference approximation and a conservative interference approximation is proposed for the probability of transmission success. These approximations are tight in the low traffic and high traffic densities respectively. In the subsequent part of the thesis, the developed model is extended to multi-hop IVC because several vehicular applications require going beyond the local communication and efficiently disseminate information across the roads via multi-hops. Two well-known greedy packet forwarding schemes are

No genetic tradeoffs between hygienic behaviour and individual innate immunity in the honey bee, Apis mellifera.

Science.gov (United States)

Harpur, Brock A; Chernyshova, Anna; Soltani, Arash; Tsvetkov, Nadejda; Mahjoorighasrodashti, Mohammad; Xu, Zhixing; Zayed, Amro

2014-01-01

Many animals have individual and social mechanisms for combating pathogens. Animals may exhibit short-term physiological tradeoffs between social and individual immunity because the latter is often energetically costly. Genetic tradeoffs between these two traits can also occur if mutations that enhance social immunity diminish individual immunity, or vice versa. Physiological tradeoffs between individual and social immunity have been previously documented in insects, but there has been no study of genetic tradeoffs involving these traits. There is strong evidence that some genes influence both innate immunity and behaviour in social insects--a prerequisite for genetic tradeoffs. Quantifying genetic tradeoffs is critical for understanding the evolution of immunity in social insects and for devising effective strategies for breeding disease-resistant pollinator populations. We conducted two experiments to test the hypothesis of a genetic tradeoff between social and individual immunity in the honey bee, Apis mellifera. First, we estimated the relative contribution of genetics to individual variation in innate immunity of honey bee workers, as only heritable traits can experience genetic tradeoffs. Second, we examined if worker bees with hygienic sisters have reduced individual innate immune response. We genotyped several hundred workers from two colonies and found that patriline genotype does not significantly influence the antimicrobial activity of a worker's hemolymph. Further, we did not find a negative correlation between hygienic behaviour and the average antimicrobial activity of a worker's hemolymph across 30 honey bee colonies. Taken together, our work indicates no genetic tradeoffs between hygienic behaviour and innate immunity in honey bees. Our work suggests that using artificial selection to increase hygienic behaviour of honey bee colonies is not expected to concurrently compromise individual innate immunity of worker bees.

Visualisation of uncertainty for the trade-off triangle used in sustainable agriculture

Science.gov (United States)

Harris, Paul; Takahashi, Taro; Lee, Michael

2017-04-01

Agriculture at the global-scale is at a critical juncture where competing requirements for maximal production and minimal pollution have led to the concept of sustainable intensification. All farming systems (arable, grasslands, etc.) are part of this debate, where each have particular associated environmental risks such as water and air pollution, greenhouse gas emissions and soil degradation, as well as issues affecting production efficiency, product quality and consumer acceptability, reflected in the development of agricultural sustainability policies. These challenges necessitate multidisciplinary solutions that can only be properly researched, implemented and tested in real-world production systems which are suited to their geographical and climatic production practice. In this respect, various high-profile agricultural data collection experiments have been set up, such as the North Wyke Farm Platform (http://www.rothamsted.ac.uk/farmplatform) to research agricultural productivity and ecosystem responses to different management practices. In this farm-scale grasslands experiment, data on hydrology, emissions, nutrient cycling, biodiversity, productivity and livestock welfare/health are collected, that in turn, are converted to trade-off metrics with respect to: (i) economic profits, (ii) societal benefits and (iii) environmental concerns, under the umbrella of sustainable intensification. Similar agriculture research platforms have similar objectives, where data collections are ultimately synthesised into trade-off metrics. Trade-offs metrics can then be usefully visualized via the usual sustainable triangle, with a new triangle for each key time period (e.g. baseline versus post-baseline). This enables a visual assessment of change in sustainability harmony or discord, according to the remit of the given research experiment. In this paper, we discuss different approaches to calculation of the sustainability trade-off metrics that are required from the farm

Using grizzly bears to assess harvest-ecosystem tradeoffs in salmon fisheries.

Science.gov (United States)

Levi, Taal; Darimont, Chris T; Macduffee, Misty; Mangel, Marc; Paquet, Paul; Wilmers, Christopher C

2012-01-01

Implementation of ecosystem-based fisheries management (EBFM) requires a clear conceptual and quantitative framework for assessing how different harvest options can modify benefits to ecosystem and human beneficiaries. We address this social-ecological need for Pacific salmon fisheries, which are economically valuable but intercept much of the annual pulse of nutrient subsidies that salmon provide to terrestrial and aquatic food webs. We used grizzly bears, vectors of salmon nutrients and animals with densities strongly coupled to salmon abundance, as surrogates for "salmon ecosystem" function. Combining salmon biomass and stock-recruitment data with stable isotope analysis, we assess potential tradeoffs between fishery yields and bear population densities for six sockeye salmon stocks in Bristol Bay, Alaska, and British Columbia (BC), Canada. For the coastal stocks, we find that both bear densities and fishery yields would increase substantially if ecosystem allocations of salmon increase from currently applied lower to upper goals and beyond. This aligning of benefits comes at a potential cost, however, with the possibility of forgoing harvests in low productivity years. In contrast, we detect acute tradeoffs between bear densities and fishery yields in interior stocks within the Fraser River, BC, where biomass from other salmon species is low. There, increasing salmon allocations to ecosystems would benefit threatened bear populations at the cost of reduced long-term yields. To resolve this conflict, we propose an EBFM goal that values fisheries and bears (and by extension, the ecosystem) equally. At such targets, ecosystem benefits are unexpectedly large compared with losses in fishery yields. To explore other management options, we generate tradeoff curves that provide stock-specific accounting of the expected loss to fishers and gain to bears as more salmon escape the fishery. Our approach, modified to suit multiple scenarios, provides a generalizable method

Using grizzly bears to assess harvest-ecosystem tradeoffs in salmon fisheries.

Directory of Open Access Journals (Sweden)

Taal Levi

Full Text Available Implementation of ecosystem-based fisheries management (EBFM requires a clear conceptual and quantitative framework for assessing how different harvest options can modify benefits to ecosystem and human beneficiaries. We address this social-ecological need for Pacific salmon fisheries, which are economically valuable but intercept much of the annual pulse of nutrient subsidies that salmon provide to terrestrial and aquatic food webs. We used grizzly bears, vectors of salmon nutrients and animals with densities strongly coupled to salmon abundance, as surrogates for "salmon ecosystem" function. Combining salmon biomass and stock-recruitment data with stable isotope analysis, we assess potential tradeoffs between fishery yields and bear population densities for six sockeye salmon stocks in Bristol Bay, Alaska, and British Columbia (BC, Canada. For the coastal stocks, we find that both bear densities and fishery yields would increase substantially if ecosystem allocations of salmon increase from currently applied lower to upper goals and beyond. This aligning of benefits comes at a potential cost, however, with the possibility of forgoing harvests in low productivity years. In contrast, we detect acute tradeoffs between bear densities and fishery yields in interior stocks within the Fraser River, BC, where biomass from other salmon species is low. There, increasing salmon allocations to ecosystems would benefit threatened bear populations at the cost of reduced long-term yields. To resolve this conflict, we propose an EBFM goal that values fisheries and bears (and by extension, the ecosystem equally. At such targets, ecosystem benefits are unexpectedly large compared with losses in fishery yields. To explore other management options, we generate tradeoff curves that provide stock-specific accounting of the expected loss to fishers and gain to bears as more salmon escape the fishery. Our approach, modified to suit multiple scenarios, provides a

Evolutionary trade-offs in kidney injury and repair.

Science.gov (United States)

Lei, Yutian; Anders, Hans-Joachim

2017-11-01

Evolutionary medicine has proven helpful to understand the origin of human disease, e.g. in identifying causal roles of recent environmental changes impacting on human physiology (environment-phenotype mismatch). In contrast, diseases affecting only a limited number of members of a species often originate from evolutionary trade-offs for usually physiologic adaptations assuring reproductive success in the context of extrinsic threats. For example, the G1 and G2 variants of the APOL1 gene supporting control of Trypanosoma infection come with the trade-off that they promote the progression of kidney disease. In this review we extend the concept of evolutionary nephrology by discussing how the physiologic adaptations (danger responses) to tissue injury create evolutionary trade-offs that drive histopathological changes underlying acute and chronic kidney diseases. The evolution of multicellular organisms positively selected a number of danger response programs for their overwhelming benefits in assuring survival such as clotting, inflammation, epithelial healing and mesenchymal healing, i.e. fibrosis and sclerosis. Upon kidney injury these danger programs often present as pathomechanisms driving persistent nephron loss and renal failure. We explore how classic kidney disease entities involve insufficient or overshooting activation of these danger response programs for which the underlying genetic basis remains largely to be defined. Dissecting the causative and hierarchical relationships between danger programs should help to identify molecular targets to control kidney injury and to improve disease outcomes.

Economic modeling of fault tolerant flight control systems in commercial applications

Science.gov (United States)

Finelli, G. B.

1982-01-01

This paper describes the current development of a comprehensive model which will supply the assessment and analysis capability to investigate the economic viability of Fault Tolerant Flight Control Systems (FTFCS) for commercial aircraft of the 1990's and beyond. An introduction to the unique attributes of fault tolerance and how they will influence aircraft operations and consequent airline costs and benefits is presented. Specific modeling issues and elements necessary for accurate assessment of all costs affected by ownership and operation of FTFCS are delineated. Trade-off factors are presented, aimed at exposing economically optimal realizations of system implementations, resource allocation, and operating policies. A trade-off example is furnished to graphically display some of the analysis capabilities of the comprehensive simulation model now being developed.

No Evidence of Trade-Off between Farm Efficiency and Resilience: Dependence of Resource-Use Efficiency on Land-Use Diversity.

Directory of Open Access Journals (Sweden)

Helena Kahiluoto

Full Text Available Efficiency in the use of resources stream-lined for expected conditions could lead to reduced system diversity and consequently endanger resilience. We tested the hypothesis of a trade-off between farm resource-use efficiency and land-use diversity. We applied stochastic frontier production models to assess the dependence of resource-use-efficiency on land-use diversity as illustrated by the Shannon-Weaver index. Total revenue in relation to use of capital, land and labour on the farms in Southern Finland with a size exceeding 30 ha was studied. The data were extracted from the Finnish Profitability Bookkeeping data. Our results indicate that there is either no trade-off or a negligible trade-off of no economic importance. The small dependence of resource-use efficiency on land-use diversity can be positive as well as negative. We conclude that diversification as a strategy to enhance farm resilience does not necessarily constrain resource-use efficiency.

A tradeoff between the losses caused by computer viruses and the risk of the manpower shortage

NARCIS (Netherlands)

Bi, Jichao; Yang, L.; Yang, Xiaofan; Wu, Yingbo; Tang, Yuan Yan

2018-01-01

This article addresses the tradeoff between the losses caused by a new virus and the size of the team for developing an antivirus against the virus. First, an individual-level virus spreading model is proposed to capture the spreading process of the virus before the appearance of its natural

Waste Isolation Pilot Plant: Alcove Gas Barrier trade-off study

International Nuclear Information System (INIS)

Lin, M.S.; Van Sambeek, L.L.

1992-07-01

A modified Kepner-Tregoe method was used for a trade-off study of Alcove Gas Barrier (AGB) concepts for the Waste Isolation Pilot Plant. The AGB is a gas-constraining seal to be constructed in an alcove entrance drift. In this trade-off study, evaluation criteria were first selected. Then these criteria were classified as to their importance to the task, assigning a weighting value to each aspect. Eleven conceptual design alternatives were developed based on geometrical/geological considerations, construction materials, constructibility, and other relevant factors and evaluated

Shifts in growth strategies reflect tradeoffs in cellular economics

Science.gov (United States)

Molenaar, Douwe; van Berlo, Rogier; de Ridder, Dick; Teusink, Bas

2009-01-01

The growth rate-dependent regulation of cell size, ribosomal content, and metabolic efficiency follows a common pattern in unicellular organisms: with increasing growth rates, cell size and ribosomal content increase and a shift to energetically inefficient metabolism takes place. The latter two phenomena are also observed in fast growing tumour cells and cell lines. These patterns suggest a fundamental principle of design. In biology such designs can often be understood as the result of the optimization of fitness. Here we show that in basic models of self-replicating systems these patterns are the consequence of maximizing the growth rate. Whereas most models of cellular growth consider a part of physiology, for instance only metabolism, the approach presented here integrates several subsystems to a complete self-replicating system. Such models can yield fundamentally different optimal strategies. In particular, it is shown how the shift in metabolic efficiency originates from a tradeoff between investments in enzyme synthesis and metabolic yields for alternative catabolic pathways. The models elucidate how the optimization of growth by natural selection shapes growth strategies. PMID:19888218

No genetic tradeoffs between hygienic behaviour and individual innate immunity in the honey bee, Apis mellifera.

Directory of Open Access Journals (Sweden)

Brock A Harpur

Full Text Available Many animals have individual and social mechanisms for combating pathogens. Animals may exhibit short-term physiological tradeoffs between social and individual immunity because the latter is often energetically costly. Genetic tradeoffs between these two traits can also occur if mutations that enhance social immunity diminish individual immunity, or vice versa. Physiological tradeoffs between individual and social immunity have been previously documented in insects, but there has been no study of genetic tradeoffs involving these traits. There is strong evidence that some genes influence both innate immunity and behaviour in social insects--a prerequisite for genetic tradeoffs. Quantifying genetic tradeoffs is critical for understanding the evolution of immunity in social insects and for devising effective strategies for breeding disease-resistant pollinator populations. We conducted two experiments to test the hypothesis of a genetic tradeoff between social and individual immunity in the honey bee, Apis mellifera. First, we estimated the relative contribution of genetics to individual variation in innate immunity of honey bee workers, as only heritable traits can experience genetic tradeoffs. Second, we examined if worker bees with hygienic sisters have reduced individual innate immune response. We genotyped several hundred workers from two colonies and found that patriline genotype does not significantly influence the antimicrobial activity of a worker's hemolymph. Further, we did not find a negative correlation between hygienic behaviour and the average antimicrobial activity of a worker's hemolymph across 30 honey bee colonies. Taken together, our work indicates no genetic tradeoffs between hygienic behaviour and innate immunity in honey bees. Our work suggests that using artificial selection to increase hygienic behaviour of honey bee colonies is not expected to concurrently compromise individual innate immunity of worker bees.

Profit Analysis and Supply Chain Planning Model for Closed-Loop Supply Chain in Fashion Industry

Directory of Open Access Journals (Sweden)

Jisoo Oh

2014-12-01

Full Text Available In recent decades, due to market growth and use of synthetic fiber, the fashion industry faces a rapid increase of CO2 emission throughout the production cycle and raises environmental issues in recovery processing. This study proposes a closed-loop supply chain (CLSC structure in fashion industry and develops its planning model as multi-objective mixed integer linear programming to find an optimal trade-off between CLSC profit and CO2 emission. The planning model is associated with the profit analysis of each member in CLSC to find the optimal price of products on CLSC network. The model determines optimal production, transportation, and inventory quantities on CLSC network. The proposed models are validated using numerical experiments and sensitivity analyses, and from the results some managerial insights are addressed.

Building America Performance Analysis Procedures: Revision 1

Energy Technology Data Exchange (ETDEWEB)

None

2004-06-01

To measure progress toward multi-year research goals, cost and performance trade-offs are evaluated through a series of controlled field and laboratory experiments supported by energy analysis techniques using test data to calibrate simulation models.

The need for a characteristics-based approach to radioactive waste classification as informed by advanced nuclear fuel cycles using the fuel-cycle integration and tradeoffs (FIT) model

International Nuclear Information System (INIS)

Djokic, D.; Piet, S.; Pincock, L.; Soelberg, N.

2013-01-01

This study explores the impact of wastes generated from potential future fuel cycles and the issues presented by classifying these under current classification criteria, and discusses the possibility of a comprehensive and consistent characteristics-based classification framework based on new waste streams created from advanced fuel cycles. A static mass flow model, Fuel-Cycle Integration and Tradeoffs (FIT), was used to calculate the composition of waste streams resulting from different nuclear fuel cycle choices. Because heat generation is generally the most important factor limiting geological repository areal loading, this analysis focuses on the impact of waste form heat load on waste classification practices, although classifying by metrics of radiotoxicity, mass, and volume is also possible. Waste streams generated in different fuel cycles and their possible classification based on the current U.S. framework and international standards are discussed. It is shown that the effects of separating waste streams are neglected under a source-based radioactive waste classification system. (authors)

Ground Vehicle System Integration (GVSI) and Design Optimization Model

National Research Council Canada - National Science Library

Horton, William

1996-01-01

This report documents the Ground Vehicle System Integration (GVSI) and Design Optimization Model GVSI is a top-level analysis tool designed to support engineering tradeoff studies and vehicle design optimization efforts...

Memory architecture for efficient utilization of SDRAM: a case study of the computation/memory access trade-off

DEFF Research Database (Denmark)

Gleerup, Thomas Møller; Holten-Lund, Hans Erik; Madsen, Jan

2000-01-01

. In software, forward differencing is usually better, but in this hardware implementation, the trade-off has made it possible to develop a very regular memory architecture with a buffering system, which can reach 95% bandwidth utilization using off-the-shelf SDRAM, This is achieved by changing the algorithm......This paper discusses the trade-off between calculations and memory accesses in a 3D graphics tile renderer for visualization of data from medical scanners. The performance requirement of this application is a frame rate of 25 frames per second when rendering 3D models with 2 million triangles, i...... to use a memory access strategy with write-only and read-only phases, and a buffering system, which uses round-robin bank write-access combined with burst read-access....

A Decision Support System for Assessing Trade-Offs between Ecosystem Management Goals: An Application in Portugal

Directory of Open Access Journals (Sweden)

Jordi Garcia-Gonzalo

2014-12-01

Full Text Available Cork oak (Quercus suber L. and holm oak (Quercus rotundifolia ecosystems are characteristic of Mediterranean forestry in Portugal. Even though cork is the most valuable product, these ecosystems provide multiple products and services. Assessing trade-offs between multiple goals is thus critical for the effectiveness of oak ecosystem management planning. This paper focuses on the development of a decision support system for oak ecosystems’ scenario analysis including multiple criteria. It includes an innovative decision support systems (DSS functionality to assess trade-offs between the criteria that may support negotiation and consensus building between decision-makers and forest stakeholders. Specifically, a module that encapsulates the Feasible Goals Method/Interactive Decision Maps (FGM/IDM technique is developed for interactive visualization of the Pareto frontier. The Pareto frontier illustrates the degree to which improving one particular criterion requires accepting sacrifices in the achievements of others. It thus provides information about trade-offs between competing decision-makers’ preferences. Results are discussed for a large-scale application encompassing over 1 million ha of cork and holm oak forest ecosystems in Southern Portugal. This study demonstrates the potential of the new DSS functionality to enhance multi-objective forest planning, namely by facilitating participation by stakeholders and providing transparency to the decision-making processes.

Trade-offs between reproductive allocation and storage in species of Oenothera L. (Onagraceae) native to Argentina

Science.gov (United States)

Vilela, Alejandra; Cariaga, Rodrigo; González-Paleo, Luciana; Ravetta, Damián

2008-01-01

A trade-off between reproduction and survival arises because current reproduction diminishes levels of a limiting resource such that less can be placed in storage organs for the survival of an organism during the unfavorable season. Oenothera is a particularly suited genus for studying those kind of trade-offs because it contains species with different life-history strategies (annual, biennial and perennial). Since allocation to leaves is a major factor associated with changes in life-history, here we tested the hypothesis that Oenothera leaf attributes would affect plant reproductive effort and therefore, root reserves. We selected two groups of taxa differing in their leaf area ratio (low- and high-LAR) and we compared their pattern of resource allocation to growth, reproduction and storage. Path analysis confirmed our hypothesis that LAR is the most important variable in explaining variation in allocation to reproduction or storage. The group with high allocation to leaves assigned resources preferentially to storage while the other group allocated more resources to reproduction, as predicted. A trade-off between reproduction and storage was only confirmed for the high-LAR group. The low-LAR group showed the life-history tactic of annual plants, while the high-LAR group exhibited a strategy generally associated with perenniality.

A new approach to the tradeoff between quality and accessibility of health care.

Science.gov (United States)

Tanke, Marit A C; Ikkersheim, David E

2012-05-01

Quality of care is associated with patient volume. Regionalization of care is therefore one of the approaches that is suited to improve quality of care. A disadvantage of regionalization is that the accessibility of the facilities can decrease. By investigating the tradeoff between quality and accessibility it is possible to determine the optimal amount of treatment locations in a health care system. In this article we present a new model to quantitatively 'solve' this tradeoff. We use the condition breast cancer in the Netherlands as an example. We calculated the expected quality gains in Quality Adjusted Lifetime Years (QALY's) due to stepwise regionalization using 'volume-outcome' literature for breast cancer. Decreased accessibility was operationalized as increased (travel) costs due to regionalization by using demographic data, drive-time information, and the national median income. The total sum of the quality and accessibility function determines the optimum range of treatment locations for this particular condition, given the 'volume-quality' relationship and Dutch demographics and geography. Currently, 94 locations offer breast cancer treatment in the Netherlands. Our model estimates that the optimum range of treatment locations for this particular condition in the Netherlands varies from 15 locations to 44 locations. Our study shows that the Dutch society would benefit from regionalization of breast cancer care as possible quality gains outweigh heightened travel costs. In addition, this model can be used for other medical conditions and in other countries. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Speed-Accuracy Tradeoffs in Speech Production

Science.gov (United States)

2017-06-01

capacity of discrete motor responses under different cognitive sets. Journal of Experimental Psychology , 71 (4), 475. SPEED-ACCURACY TRADEOFFS IN HUMAN...space defined by vocal tract constriction degree and location, as in Articulatory Phonology Browman & Goldstein (1992). These high-level spaces are...relationship between speech gestures varies as a function of their positions within the syllable Browman & Goldstein (1995); Krakow (1999); Byrd et al

Hydroeconomic analysis

DEFF Research Database (Denmark)

Bauer-Gottwein, Peter; Riegels, Niels; Pulido-Velazquez, Manuel

2017-01-01

Hydroeconomic analysis and modeling provides a consistent and quantitative framework to assess the links between water resources systems and economic activities related to water use, simultaneously modeling water supply and water demand. It supports water managers and decision makers in assessing...... trade-offs between different water uses, different geographic regions, and various economic sectors and between the present and the future. Hydroeconomic analysis provides consistent economic performance criteria for infrastructure development and institutional reform in water policies and management...... organizations. This chapter presents an introduction to hydroeconomic analysis and modeling, and reviews the state of the art in the field. We review available economic water-valuation techniques and summarize the main types of decision problems encountered in hydroeconomic analysis. Popular solution strategies...

[Trade-offs in the development of various dosage form (overview)].

Science.gov (United States)

Uchida, Takahiro

2015-01-01

In this symposium we focused on trade-offs which might occur in the process of development of many types of formulation and corresponding dissolution methods. Firstly, we focused on a solubility-permeability trade-off in the case of micelle with surfactant or molecular complex with CyD. The micelle would be successful in increasing drug solubility, however it rather decreased permeability of model drug progesterone (Biopharmaceutics Classfication System (BCS) Class II) as an overall flux. Secondly in order to reduce bitterness of branched chain amino acid (BCAA), increasing particle sizes of each amino acid crystals involved in formulation was effective since the release rate of amino acid was restricted efficiently. Thirdly, in the case of injection of paclitaxel (BCS Class II)formulation, the drug was adsorbed to albumin. Thereby the risk of allergy was dramatically decreased compared to the case when non-ionic surfactant was used as an additive. Fourth, anticancer drug was incorporated into the internal (core) phase of an orally disintegrating tablet (ODT), this is also merit to avoid exposure of the drug to a nursing person or individual working person in manufacturing process. Fifth, the convenient syringe type kit pharmaceutical preparation for administration of total parenteral nutrition (TPN) to avoid incompatibility and its risk management effect was briefly discussed. Finally, the risk of an additive such as alcohol for a preterm infant was described.

Trade-off results and preliminary designs of Near-Term Hybrid Vehicles

Science.gov (United States)

Sandberg, J. J.

1980-01-01

Phase I of the Near-Term Hybrid Vehicle Program involved the development of preliminary designs of electric/heat engine hybrid passenger vehicles. The preliminary designs were developed on the basis of mission analysis, performance specification, and design trade-off studies conducted independently by four contractors. THe resulting designs involve parallel hybrid (heat engine/electric) propulsion systems with significant variation in component selection, power train layout, and control strategy. Each of the four designs is projected by its developer as having the potential to substitute electrical energy for 40% to 70% of the petroleum fuel consumed annually by its conventional counterpart.

Stakeholders' Responses to CSR Tradeoffs: When Other-Orientation and Trust Trump Material Self-Interest

Science.gov (United States)

Bridoux, Flore; Stofberg, Nicole; Den Hartog, Deanne

2016-01-01

When investing in corporate social responsibility (CSR), managers may strive for a win-win scenario where all stakeholders end up better off, but they may not always be able to avoid trading off stakeholders' interests. To provide guidance to managers who have to make tradeoffs, this study used a vignette-based experiment to explore stakeholders' intention to associate with a firm (i.e., buy from or become an employee) that trades off CSR directed at the stakeholders' own group (self-directed CSR) and CSR directed at another stakeholder group (other-directed CSR). Results show that stakeholders were not systematically more attracted to a firm that favors their own group over another stakeholder group. Specifically, stakeholders' other-orientation moderated their reaction to tradeoffs: stakeholders higher on other-orientation were willing to forego some material benefits to associate with a firm that treated suppliers in developing countries significantly better than its competitors, whereas stakeholders lower on other-orientation were more attracted to a firm favoring their own stakeholder group. Other-orientation also moderated reactions to tradeoffs involving the environment, although high CSR directed at the environment did not compensate for low self-directed CSR even for stakeholders higher on other-orientation. Second, the vignette study showed that trust mediated the relationship between tradeoffs and stakeholders' reactions. The study contributes first and foremost to the burgeoning literature on CSR tradeoffs and to the multimotive approach to CSR, which claims that other motives can drive stakeholders' reactions to CSR in addition to self-interest. First, it provides further evidence that studying CSR tradeoffs is important to understand both (prospective) employees' and customers' reactions to CSR-related activities. Second, it identifies other-orientation as a motive-related individual difference that explains heterogeneity in stakeholders' reactions to

Stakeholders' Responses to CSR Tradeoffs: When Other-Orientation and Trust Trump Material Self-Interest.

Science.gov (United States)

Bridoux, Flore; Stofberg, Nicole; Den Hartog, Deanne

2015-01-01

When investing in corporate social responsibility (CSR), managers may strive for a win-win scenario where all stakeholders end up better off, but they may not always be able to avoid trading off stakeholders' interests. To provide guidance to managers who have to make tradeoffs, this study used a vignette-based experiment to explore stakeholders' intention to associate with a firm (i.e., buy from or become an employee) that trades off CSR directed at the stakeholders' own group (self-directed CSR) and CSR directed at another stakeholder group (other-directed CSR). Results show that stakeholders were not systematically more attracted to a firm that favors their own group over another stakeholder group. Specifically, stakeholders' other-orientation moderated their reaction to tradeoffs: stakeholders higher on other-orientation were willing to forego some material benefits to associate with a firm that treated suppliers in developing countries significantly better than its competitors, whereas stakeholders lower on other-orientation were more attracted to a firm favoring their own stakeholder group. Other-orientation also moderated reactions to tradeoffs involving the environment, although high CSR directed at the environment did not compensate for low self-directed CSR even for stakeholders higher on other-orientation. Second, the vignette study showed that trust mediated the relationship between tradeoffs and stakeholders' reactions. The study contributes first and foremost to the burgeoning literature on CSR tradeoffs and to the multimotive approach to CSR, which claims that other motives can drive stakeholders' reactions to CSR in addition to self-interest. First, it provides further evidence that studying CSR tradeoffs is important to understand both (prospective) employees' and customers' reactions to CSR-related activities. Second, it identifies other-orientation as a motive-related individual difference that explains heterogeneity in stakeholders' reactions to

Stakeholders’ responses to CSR tradeoffs: When other-orientation and trust trump material self-interest

Directory of Open Access Journals (Sweden)

Flore eBridoux

2016-01-01

Full Text Available When investing in corporate social responsibility (CSR, managers may strive for a win-win scenario where all stakeholders end up better off, but they may not always be able to avoid trading off stakeholders’ interests. To provide guidance to managers who have to make tradeoffs, this study used a vignette-based experiment to explore stakeholders’ intention to associate with a firm (i.e., buy from or become an employee that trades off CSR directed at the stakeholders’ own group (self-directed CSR and CSR directed at another stakeholder group (other-directed CSR. Results show that stakeholders were not systematically more attracted to a firm that favors their own group over another stakeholder group. Specifically, stakeholders’ other-orientation moderated their reaction to tradeoffs: stakeholders higher on other-orientation were willing to forego some material benefits to associate with a firm that treated suppliers in developing countries significantly better than its competitors, whereas stakeholders lower on other-orientation were more attracted to a firm favoring their own stakeholder group. Other-orientation also moderated reactions to tradeoffs involving the environment, although high CSR directed at the environment did not compensate for low self-directed CSR even for stakeholders higher on other-orientation. Second, the vignette study showed that trust mediated the relationship between tradeoffs and stakeholders’ reactions. The study contributes first and foremost to the burgeoning literature on CSR tradeoffs and to the multimotive approach to CSR, which claims that other motives can drive stakeholders’ reactions to CSR in addition to self-interest. First, it provides further evidence that studying CSR tradeoffs is important to understand both (prospective employees’ and customers’ reactions to CSR-related activities. Second, it identifies other-orientation as a motive-related individual difference that explains

Testing the competition-colonization trade-off with a 32-year study of a saxicolous lichen community.

Science.gov (United States)

Pastore, A I; Prather, C M; Gornish, E S; Ryan, W H; Ellis, R D; Milleri, T E

2014-02-01

Competition-colonization trade-offs are theorized to be a mechanism of coexistence in communities structured by environmental fluctuations. But many studies that have tested for the trade-off have failed to detect it, likely because a spatiotemporally structured environment and many species assemblages are needed to adequately test for a competition-colonization trade-off. Here, we present a unique 32-year study of rock-dwelling lichens in New Mexico, USA, in which photographs were used to quantify lichen life history traits and interactions through time. These data allowed us to determine whether there were any trade-offs between traits associated with colonization and competition, as well as the relationship between diversity and disturbance in the community. We did not find evidence for a trade-off between competitive ability and colonization rate or any related life history traits. Interestingly, we did find a peak in all measures of species diversity at intermediate levels of disturbance, consistent with the intermediate disturbance hypothesis pattern. We suggest that the coexistence of the dominant species in this system is regulated by differences in persistence and growth rate mediating overgrowth competition rather than a competition-colonization trade-off.

Energy/Reliability Trade-offs in Fault-Tolerant Event-Triggered Distributed Embedded Systems

DEFF Research Database (Denmark)

Gan, Junhe; Gruian, Flavius; Pop, Paul

2011-01-01

task, such that transient faults are tolerated, the timing constraints of the application are satisfied, and the energy consumed is minimized. Tasks are scheduled using fixed-priority preemptive scheduling, while replication is used for recovery from multiple transient faults. Addressing energy...... and reliability simultaneously is especially challenging, since lowering the voltage to reduce the energy consumption has been shown to increase the transient fault rate. We presented a Tabu Search-based approach which uses an energy/reliability trade-off model to find reliable and schedulable implementations...

Functional trade-off between strength and thermal capacity of dermal armor: Insights from girdled lizards.

Science.gov (United States)

Broeckhoven, Chris; du Plessis, Anton; Hui, Cang

2017-10-01

The presence of dermal armor is often unambiguously considered the result of an evolutionary predator-prey arms-race. Recent studies focusing predominantly on osteoderms - mineralized elements embedded in the dermis layer of various extant and extinct vertebrates - have instead proposed that dermal armor might exhibit additional functionalities besides protection. Multiple divergent functionalities could impose conflicting demands on a phenotype, yet, functional trade-offs in dermal armor have rarely been investigated. Here, we use high-resolution micro-computed tomography and voxel-based simulations to test for a trade-off between the strength and thermal capacity of osteoderms using two armored cordylid lizards as model organisms. We demonstrate that high vascularization, associated with improved thermal capacity might limit the strength of osteoderms. These results call for a holistic, cautionary future approach to studies investigating dermal armor, especially those aiming to inspire artificial protective materials. Copyright © 2017 Elsevier Ltd. All rights reserved.

Form of an evolutionary tradeoff affects eco-evolutionary dynamics in a predator-prey system.

Science.gov (United States)

Kasada, Minoru; Yamamichi, Masato; Yoshida, Takehito

2014-11-11

Evolution on a time scale similar to ecological dynamics has been increasingly recognized for the last three decades. Selection mediated by ecological interactions can change heritable phenotypic variation (i.e., evolution), and evolution of traits, in turn, can affect ecological interactions. Hence, ecological and evolutionary dynamics can be tightly linked and important to predict future dynamics, but our understanding of eco-evolutionary dynamics is still in its infancy and there is a significant gap between theoretical predictions and empirical tests. Empirical studies have demonstrated that the presence of genetic variation can dramatically change ecological dynamics, whereas theoretical studies predict that eco-evolutionary dynamics depend on the details of the genetic variation, such as the form of a tradeoff among genotypes, which can be more important than the presence or absence of the genetic variation. Using a predator-prey (rotifer-algal) experimental system in laboratory microcosms, we studied how different forms of a tradeoff between prey defense and growth affect eco-evolutionary dynamics. Our experimental results show for the first time to our knowledge that different forms of the tradeoff produce remarkably divergent eco-evolutionary dynamics, including near fixation, near extinction, and coexistence of algal genotypes, with quantitatively different population dynamics. A mathematical model, parameterized from completely independent experiments, explains the observed dynamics. The results suggest that knowing the details of heritable trait variation and covariation within a population is essential for understanding how evolution and ecology will interact and what form of eco-evolutionary dynamics will result.

Sibling Competition & Growth Tradeoffs. Biological vs. Statistical Significance.

Science.gov (United States)

Kramer, Karen L; Veile, Amanda; Otárola-Castillo, Erik

2016-01-01

Early childhood growth has many downstream effects on future health and reproduction and is an important measure of offspring quality. While a tradeoff between family size and child growth outcomes is theoretically predicted in high-fertility societies, empirical evidence is mixed. This is often attributed to phenotypic variation in parental condition. However, inconsistent study results may also arise because family size confounds the potentially differential effects that older and younger siblings can have on young children's growth. Additionally, inconsistent results might reflect that the biological significance associated with different growth trajectories is poorly understood. This paper addresses these concerns by tracking children's monthly gains in height and weight from weaning to age five in a high fertility Maya community. We predict that: 1) as an aggregate measure family size will not have a major impact on child growth during the post weaning period; 2) competition from young siblings will negatively impact child growth during the post weaning period; 3) however because of their economic value, older siblings will have a negligible effect on young children's growth. Accounting for parental condition, we use linear mixed models to evaluate the effects that family size, younger and older siblings have on children's growth. Congruent with our expectations, it is younger siblings who have the most detrimental effect on children's growth. While we find statistical evidence of a quantity/quality tradeoff effect, the biological significance of these results is negligible in early childhood. Our findings help to resolve why quantity/quality studies have had inconsistent results by showing that sibling competition varies with sibling age composition, not just family size, and that biological significance is distinct from statistical significance.

Sibling Competition & Growth Tradeoffs. Biological vs. Statistical Significance.

Directory of Open Access Journals (Sweden)

Karen L Kramer

Full Text Available Early childhood growth has many downstream effects on future health and reproduction and is an important measure of offspring quality. While a tradeoff between family size and child growth outcomes is theoretically predicted in high-fertility societies, empirical evidence is mixed. This is often attributed to phenotypic variation in parental condition. However, inconsistent study results may also arise because family size confounds the potentially differential effects that older and younger siblings can have on young children's growth. Additionally, inconsistent results might reflect that the biological significance associated with different growth trajectories is poorly understood. This paper addresses these concerns by tracking children's monthly gains in height and weight from weaning to age five in a high fertility Maya community. We predict that: 1 as an aggregate measure family size will not have a major impact on child growth during the post weaning period; 2 competition from young siblings will negatively impact child growth during the post weaning period; 3 however because of their economic value, older siblings will have a negligible effect on young children's growth. Accounting for parental condition, we use linear mixed models to evaluate the effects that family size, younger and older siblings have on children's growth. Congruent with our expectations, it is younger siblings who have the most detrimental effect on children's growth. While we find statistical evidence of a quantity/quality tradeoff effect, the biological significance of these results is negligible in early childhood. Our findings help to resolve why quantity/quality studies have had inconsistent results by showing that sibling competition varies with sibling age composition, not just family size, and that biological significance is distinct from statistical significance.

Ocean Acidification May Aggravate Social-Ecological Trade-Offs in Coastal Fisheries

Science.gov (United States)

Voss, Rudi; Quaas, Martin F.; Schmidt, Jörn O.; Kapaun, Ute

2015-01-01

Ocean Acidification (OA) will influence marine ecosystems by changing species abundance and composition. Major effects are described for calcifying organisms, which are significantly impacted by decreasing pH values. Direct effects on commercially important fish are less well studied. The early life stages of fish populations often lack internal regulatory mechanisms to withstand the effects of abnormal pH. Negative effects can be expected on growth, survival, and recruitment success. Here we study Norwegian coastal cod, one of the few stocks where such a negative effect was experimentally quantified, and develop a framework for coupling experimental data on OA effects to ecological-economic fisheries models. In this paper, we scale the observed physiological responses to the population level by using the experimentally determined mortality rates as part of the stock-recruitment relationship. We then use an ecological-economic optimization model, to explore the potential effect of rising CO2 concentration on ecological (stock size), economic (profits), consumer-related (harvest) and social (employment) indicators, with scenarios ranging from present day conditions up to extreme acidification. Under the assumptions of our model, yields and profits could largely be maintained under moderate OA by adapting future fishing mortality (and related effort) to changes owing to altered pH. This adaptation comes at the costs of reduced stock size and employment, however. Explicitly visualizing these ecological, economic and social tradeoffs will help in defining realistic future objectives. Our results can be generalized to any stressor (or stressor combination), which is decreasing recruitment success. The main findings of an aggravation of trade-offs will remain valid. This seems to be of special relevance for coastal stocks with limited options for migration to avoid unfavorable future conditions and subsequently for coastal fisheries, which are often small scale local

Ocean acidification may aggravate social-ecological trade-offs in coastal fisheries.

Science.gov (United States)

Voss, Rudi; Quaas, Martin F; Schmidt, Jörn O; Kapaun, Ute

2015-01-01

Ocean Acidification (OA) will influence marine ecosystems by changing species abundance and composition. Major effects are described for calcifying organisms, which are significantly impacted by decreasing pH values. Direct effects on commercially important fish are less well studied. The early life stages of fish populations often lack internal regulatory mechanisms to withstand the effects of abnormal pH. Negative effects can be expected on growth, survival, and recruitment success. Here we study Norwegian coastal cod, one of the few stocks where such a negative effect was experimentally quantified, and develop a framework for coupling experimental data on OA effects to ecological-economic fisheries models. In this paper, we scale the observed physiological responses to the population level by using the experimentally determined mortality rates as part of the stock-recruitment relationship. We then use an ecological-economic optimization model, to explore the potential effect of rising CO2 concentration on ecological (stock size), economic (profits), consumer-related (harvest) and social (employment) indicators, with scenarios ranging from present day conditions up to extreme acidification. Under the assumptions of our model, yields and profits could largely be maintained under moderate OA by adapting future fishing mortality (and related effort) to changes owing to altered pH. This adaptation comes at the costs of reduced stock size and employment, however. Explicitly visualizing these ecological, economic and social tradeoffs will help in defining realistic future objectives. Our results can be generalized to any stressor (or stressor combination), which is decreasing recruitment success. The main findings of an aggravation of trade-offs will remain valid. This seems to be of special relevance for coastal stocks with limited options for migration to avoid unfavorable future conditions and subsequently for coastal fisheries, which are often small scale local

Coupled bias-variance tradeoff for cross-pose face recognition.

Science.gov (United States)

Li, Annan; Shan, Shiguang; Gao, Wen

2012-01-01

Subspace-based face representation can be looked as a regression problem. From this viewpoint, we first revisited the problem of recognizing faces across pose differences, which is a bottleneck in face recognition. Then, we propose a new approach for cross-pose face recognition using a regressor with a coupled bias-variance tradeoff. We found that striking a coupled balance between bias and variance in regression for different poses could improve the regressor-based cross-pose face representation, i.e., the regressor can be more stable against a pose difference. With the basic idea, ridge regression and lasso regression are explored. Experimental results on CMU PIE, the FERET, and the Multi-PIE face databases show that the proposed bias-variance tradeoff can achieve considerable reinforcement in recognition performance.

Modelagem por meio de teoria de filas do tradeoff entre investir em canais de atendimento e satisfazer o nível de serviço em provedores INTERNET A queueing model to analyse the tradeoff between investing in attending channels and satisfying service level in INTERNET providers

Directory of Open Access Journals (Sweden)

Gisele Castro Fontanella

1997-12-01

simplest one is when the user connects to a provider's attending channel by an ordinary telephone line. Finding an available channel may not be an easy task, especially during peak hours. This results in a problem for the providers, which is to determine the optimal relationship between the number of users and the number of attending channels. To solve this problem, a provider needs to analyze the tradeoff between investing in capacity (number of channels and satisfying the targeted service level to the users (probability of finding an available channel. The objective of this paper is to model this tradeoff by means of queueing theory. The methodology involves basically three steps: (i analyze user arrival (calling and service (attending processes in chosen periods, (ii select an appropriate queueing model under some simplifying assumptions, and (iii generate tradeoff curves among system performance measures, in particular, between the probability of finding an available channel and the number of channels or the mean user arrival rate. To illustrate the application of this methodology, some results deriving from a case study performed in an access provider of São Paulo state, with Poisson arrival process but non-exponential service times, are presented. Some perspectives for future research are pointed out, such as grouping users into different classes as a function of their arrival and service behavior, and analyzing capacity partitioning as a function of these classes.

No Genetic Tradeoffs between Hygienic Behaviour and Individual Innate Immunity in the Honey Bee, Apis mellifera

OpenAIRE

Harpur, Brock A.; Chernyshova, Anna; Soltani, Arash; Tsvetkov, Nadejda; Mahjoorighasrodashti, Mohammad; Xu, Zhixing; Zayed, Amro

2014-01-01

Many animals have individual and social mechanisms for combating pathogens. Animals may exhibit short-term physiological tradeoffs between social and individual immunity because the latter is often energetically costly. Genetic tradeoffs between these two traits can also occur if mutations that enhance social immunity diminish individual immunity, or vice versa. Physiological tradeoffs between individual and social immunity have been previously documented in insects, but there has been no stu...

Are trade-offs among species' ecological interactions scale dependent? A test using pitcher-plant inquiline species.

Science.gov (United States)

Kneitel, Jamie M

2012-01-01

Trade-offs among species' ecological interactions is a pervasive explanation for species coexistence. The traits associated with trade-offs are typically measured to mechanistically explain species coexistence at a single spatial scale. However, species potentially interact at multiple scales and this may be reflected in the traits among coexisting species. I quantified species' ecological traits associated with the trade-offs expected at both local (competitive ability and predator tolerance) and regional (competitive ability and colonization rate) community scales. The most common species (four protozoa and a rotifer) from the middle trophic level of a pitcher plant (Sarracenia purpurea) inquiline community were used to link species traits to previously observed patterns of species diversity and abundance. Traits associated with trade-offs (competitive ability, predator tolerance, and colonization rate) and other ecological traits (size, growth rate, and carrying capacity) were measured for each of the focal species. Traits were correlated with one another with a negative relationship indicative of a trade-off. Protozoan and rotifer species exhibited a negative relationship between competitive ability and predator tolerance, indicative of coexistence at the local community scale. There was no relationship between competitive ability and colonization rate. Size, growth rate, and carrying capacity were correlated with each other and the trade-off traits: Size was related to both competitive ability and predator tolerance, but growth rate and carrying capacity were correlated with predator tolerance. When partial correlations were conducted controlling for size, growth rate and carrying capacity, the trade-offs largely disappeared. These results imply that body size is the trait that provides the basis for ecological interactions and trade-offs. Altogether, this study showed that the examination of species' traits in the context of coexistence at different scales

Environmental/Thermal Barrier Coatings for Ceramic Matrix Composites: Thermal Tradeoff Studies

Science.gov (United States)

Murthy, Pappu L. M.; Brewer, David; Shah, Ashwin R.

2007-01-01

Recent interest in environmental/thermal barrier coatings (EBC/TBCs) has prompted research to develop life-prediction methodologies for the coating systems of advanced high-temperature ceramic matrix composites (CMCs). Heat-transfer analysis of EBC/TBCs for CMCs is an essential part of the effort. It helps establish the resulting thermal profile through the thickness of the CMC that is protected by the EBC/TBC system. This report documents the results of a one-dimensional analysis of an advanced high-temperature CMC system protected with an EBC/TBC system. The one-dimensional analysis was used for tradeoff studies involving parametric variation of the conductivity; the thickness of the EBC/TBCs, bond coat, and CMC substrate; and the cooling requirements. The insight gained from the results will be used to configure a viable EBC/TBC system for CMC liners that meet the desired hot surface, cold surface, and substrate temperature requirements.

Development and application of a model for the analysis of trades between space launch system operations and acquisition costs

Science.gov (United States)

Nix, Michael B.

2005-12-01

Early design decisions in the development of space launch systems determine the costs to acquire and operate launch systems. Some sources indicate that as much as 90% of life cycle costs are fixed by the end of the critical design review phase. System characteristics determined by these early decisions are major factors in the acquisition cost of flight hardware elements and facilities and influence operations costs through the amount of maintenance and support labor required to sustain system function. Operations costs are also dependent on post-development management decisions regarding how much labor will be deployed to meet requirements of market demand and ownership profit. The ability to perform early trade-offs between these costs is vital to the development of systems that have the necessary capacity to provide service and are profitable to operate. An Excel-based prototype model was developed for making early analyses of trade-offs between the costs to operate a space launch system and to acquire the necessary assets to meet a given set of operational requirements. The model, integrating input from existing models and adding missing capability, allows the user to make such trade-offs across a range of operations concepts (required flight rates, staffing levels, shifts per workday, workdays per week and per year, unreliability, wearout and depot maintenance) and the number, type and capability of assets (flight hardware elements, processing and supporting facilities and infrastructure). The costs and capabilities of hypothetical launch systems can be modeled as a function of interrelated turnaround times and labor resource levels, and asset loss and retirement. The number of flight components and facilities required can be calculated and the operations and acquisition costs compared for a specified scenario. Findings, based on the analysis of a hypothetical two stage to orbit, reusable, unmanned launch system, indicate that the model is suitable for the

Synthetic control of a fitness tradeoff in yeast nitrogen metabolism

Directory of Open Access Journals (Sweden)

Lee Jack J

2009-01-01

Full Text Available Abstract Background Microbial communities are involved in many processes relevant to industrial and medical biotechnology, such as the formation of biofilms, lignocellulosic degradation, and hydrogen production. The manipulation of synthetic and natural microbial communities and their underlying ecological parameters, such as fitness, evolvability, and variation, is an increasingly important area of research for synthetic biology. Results Here, we explored how synthetic control of an endogenous circuit can be used to regulate a tradeoff between fitness in resource abundant and resource limited environments in a population of Saccharomyces cerevisiae. We found that noise in the expression of a key enzyme in ammonia assimilation, Gdh1p, mediated a tradeoff between growth in low nitrogen environments and stress resistance in high ammonia environments. We implemented synthetic control of an endogenous Gdh1p regulatory network to construct an engineered strain in which the fitness of the population was tunable in response to an exogenously-added small molecule across a range of ammonia environments. Conclusion The ability to tune fitness and biological tradeoffs will be important components of future efforts to engineer microbial communities.

Science for Trade-Offs Between Conflicting Interests in Future Forests

Directory of Open Access Journals (Sweden)

Sune Linder

2011-08-01

Full Text Available Forests deliver multiple ecosystem services to society. Management of forests must be able to deal with trade-offs when the delivery of different ecosystem services comes in conflict with each other. The research program Future Forests (http://www.futureforests.se attempts to form a scientific basis for managing such trade-offs between conflicting interests in northern boreal forests. Some key characteristics of the research program are interdisciplinary and participatory research and a clear communication agenda for stakeholders. This paper gives a brief overview of the underlying ideas behind the program, and an introduction to the papers published in this Special Issue.

Endogenous testosterone is not associated with the trade-off between paternal and mating effort

NARCIS (Netherlands)

Eikenaar, Cas; Whitham, Megan; Komdeur, Jan; van der Velde, Marco; Moore, Ignacio T.

2011-01-01

Males may face a trade-off between caring for offspring and pursuing additional matings. In birds, the androgen testosterone has been suggested to be a key proximate mediator in this trade-off for several reasons. At the population level, high testosterone is typically associated with the period of

Trade-offs between sexual advertisement and immune function in the pied flycatcher (Ficedula hypoleuca).

OpenAIRE

Kilpimaa, Janne; Alatalo, Rauno V.; Siitari, Heli

2004-01-01

Good genes models of sexual selection assume that sexual advertisement is costly and thus the level of advertisement honestly reveals heritable viability. Recently it has been suggested that an important cost of sexual advertisement might be impairment of the functioning of the immune system. In this field experiment we investigated the possible trade-offs between immune function and sexual advertisement by manipulating both mating effort and activity of immune defence in male pied flycatcher...

On the Risk-Return Tradeoff in the Stock Exchange of Thailand: New Evidence

OpenAIRE

Jiranyakul, Komain

2011-01-01

This paper provides new evidence on the positive risk-return tradeoff in the Thai stock market using monthly data. An AR(p)-GARCH-in-mean model is applied to the data from January 1981 to December 2009. Since stock prices and dividend series are not cointegrated, the excess returns are separately calculated as capital gain and dividend excess returns. By incorporating the dummy variables that capture the impact of the 1987 global stock market crash and the Asian 1997 financial crisis in th...

Greenhouse Gas Emission Mitigation And Agriculture, Trade-off Or Win-win Situation: Bioeconomic Farm Modelling In The Sudanian Area of Burkina Faso

Science.gov (United States)

Some, T. E.; Barbier, B.

2015-12-01

Climate changes talks regularly underline that developing countries' agriculture could play a stronger role in GHGs mitigation strategies and benefit from the Kyoto Protocol program of subsidies. Scientists explain that agriculture can contribute to carbon mitigation by storing more carbon in the soil through greener cropping systems. In this context, a growing number of research projects have started to investigate how developing countries agriculture can contribute to these objectives. The clean development mechanism (CDM) proposed in the Kyoto protocol is one particular policy instrument that can incite farmers to mitigate the GHG balance towards more sequestration and less emission. Some economists such as Michael Porter think that environmental regulation lead to a win-win outcome, in which case subsidies are not necessary. If it is a trade-off between incomes and the environment, subsidies are required. CDM can be mobilized to support the mitigation strategy. Agriculture implies the use of inputs. Reducing the emission implies the reduction of those inputs which will in turn imply a yield decrease. The study aims to assess whether this measure will imply a trade-off between environmental and economic objectives or a win-win situation. I apply this study to the case of small farmers in Burkina Faso through environmental instruments such as the emissions limits and agroforestry using a bioeconomic model, in which the farmers maximize their utility subject to constraints. The study finds that the limitation of emissions in annual crops production involves a trade-off. by impacting negatively their net cash come. By integrating perennial crops in the farming system, the farmers' utility increases. Around 6,118 kg are sequestrated individually. By computing the value on this carbon balance, farmers' net cash incomes go better. Then practicing agroforestry is a win-win situation, as they reach a higher level of income, and reduce emissions. Policymakers must

Multi-Objective Optimization for Analysis of Changing Trade-Offs in the Nepalese Water–Energy–Food Nexus with Hydropower Development

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Sanita Dhaubanjar

2017-02-01

Full Text Available While the water–energy–food nexus approach is becoming increasingly important for more efficient resource utilization and economic development, limited quantitative tools are available to incorporate the approach in decision-making. We propose a spatially explicit framework that couples two well-established water and power system models to develop a decision support tool combining multiple nexus objectives in a linear objective function. To demonstrate our framework, we compare eight Nepalese power development scenarios based on five nexus objectives: minimization of power deficit, maintenance of water availability for irrigation to support food self-sufficiency, reduction in flood risk, maintenance of environmental flows, and maximization of power export. The deterministic multi-objective optimization model is spatially resolved to enable realistic representation of the nexus linkages and accounts for power transmission constraints using an optimal power flow approach. Basin inflows, hydropower plant specifications, reservoir characteristics, reservoir rules, irrigation water demand, environmental flow requirements, power demand, and transmission line properties are provided as model inputs. The trade-offs and synergies among these objectives were visualized for each scenario under multiple environmental flow and power demand requirements. Spatially disaggregated model outputs allowed for the comparison of scenarios not only based on fulfillment of nexus objectives but also scenario compatibility with existing infrastructure, supporting the identification of projects that enhance overall system efficiency. Though the model is applied to the Nepalese nexus from a power development perspective here, it can be extended and adapted for other problems.

Using Flow-Ecology Relationships to Evaluate Ecosystem Service Trade-Offs and Complementarities in the Nation's Largest River Swamp

Science.gov (United States)

Kozak, Justin P.; Bennett, Micah G.; Hayden-Lesmeister, Anne; Fritz, Kelley A.; Nickolotsky, Aaron

2015-06-01

Large river systems are inextricably linked with social systems; consequently, management decisions must be made within a given ecological, social, and political framework that often defies objective, technical resolution. Understanding flow-ecology relationships in rivers is necessary to assess potential impacts of management decisions, but translating complex flow-ecology relationships into stakeholder-relevant information remains a struggle. The concept of ecosystem services provides a bridge between flow-ecology relationships and stakeholder-relevant data. Flow-ecology relationships were used to explore complementary and trade-off relationships among 12 ecosystem services and related variables in the Atchafalaya River Basin, Louisiana. Results from Indicators of Hydrologic Alteration were reduced to four management-relevant hydrologic variables using principal components analysis. Multiple regression was used to determine flow-ecology relationships and Pearson correlation coefficients, along with regression results, were used to determine complementary and trade-off relationships among ecosystem services and related variables that were induced by flow. Seven ecosystem service variables had significant flow-ecology relationships for at least one hydrologic variable ( R 2 = 0.19-0.64). River transportation and blue crab ( Callinectes sapidus) landings exhibited a complementary relationship mediated by flow; whereas transportation and crawfish landings, crawfish landings and crappie ( Pomoxis spp.) abundance, and blue crab landings and blue catfish ( Ictalurus furcatus) abundance exhibited trade-off relationships. Other trade-off and complementary relationships among ecosystem services and related variables, however, were not related to flow. These results give insight into potential conflicts among stakeholders, can reduce the dimensions of management decisions, and provide initial hypotheses for experimental flow modifications.

Using Flow-Ecology Relationships to Evaluate Ecosystem Service Trade-Offs and Complementarities in the Nation's Largest River Swamp.

Science.gov (United States)

Kozak, Justin P; Bennett, Micah G; Hayden-Lesmeister, Anne; Fritz, Kelley A; Nickolotsky, Aaron

2015-06-01

Large river systems are inextricably linked with social systems; consequently, management decisions must be made within a given ecological, social, and political framework that often defies objective, technical resolution. Understanding flow-ecology relationships in rivers is necessary to assess potential impacts of management decisions, but translating complex flow-ecology relationships into stakeholder-relevant information remains a struggle. The concept of ecosystem services provides a bridge between flow-ecology relationships and stakeholder-relevant data. Flow-ecology relationships were used to explore complementary and trade-off relationships among 12 ecosystem services and related variables in the Atchafalaya River Basin, Louisiana. Results from Indicators of Hydrologic Alteration were reduced to four management-relevant hydrologic variables using principal components analysis. Multiple regression was used to determine flow-ecology relationships and Pearson correlation coefficients, along with regression results, were used to determine complementary and trade-off relationships among ecosystem services and related variables that were induced by flow. Seven ecosystem service variables had significant flow-ecology relationships for at least one hydrologic variable (R (2) = 0.19-0.64). River transportation and blue crab (Callinectes sapidus) landings exhibited a complementary relationship mediated by flow; whereas transportation and crawfish landings, crawfish landings and crappie (Pomoxis spp.) abundance, and blue crab landings and blue catfish (Ictalurus furcatus) abundance exhibited trade-off relationships. Other trade-off and complementary relationships among ecosystem services and related variables, however, were not related to flow. These results give insight into potential conflicts among stakeholders, can reduce the dimensions of management decisions, and provide initial hypotheses for experimental flow modifications.

Trade-off between information and disturbance in qubit thermometry

Science.gov (United States)

Seveso, Luigi; Paris, Matteo G. A.

2018-03-01

We address the trade-off between information and disturbance in qubit thermometry from the perspective of quantum estimation theory. Given a quantum measurement, we quantify information via the Fisher information of the measurement and disturbance via four different figures of merit, which capture different aspects (statistical, thermodynamical, geometrical) of the trade-off. For each disturbance measure, the efficient measurements, i.e., the measurements that introduce a disturbance not greater than any other measurement extracting the same amount of information, are determined explicitly. The family of efficient measurements varies with the choice of the disturbance measure. On the other hand, commutativity between the elements of the probability operator-valued measure (POVM) and the equilibrium state of the thermometer is a necessary condition for efficiency with respect to any figure of disturbance.

Energy security and climate change protection: Complementarity or tradeoff?

International Nuclear Information System (INIS)

Brown, Stephen P.A.; Huntington, Hillard G.

2008-01-01

Energy security and climate change protection have risen to the forefront of energy policy - linked in time and a perception that both goals can be achieved through the same or similar policies. Although such complementarity can exist for individual technologies, policymakers face a tradeoff between these two policy objectives. The tradeoff arises when policymakers choose the mix of individual technologies with which to reduce greenhouse gas emissions and enhance energy security. Optimal policy is achieved when the cost of the additional use of each technology equals the value of the additional energy security and reduction in greenhouse gas emission that it provides. Such an approach may draw more heavily on conventional technologies that provide benefits in only one dimension than on more costly technologies that both increase energy security and reduce greenhouse gas emissions. (author)

The Influence of Groundwater Depletion from Irrigated Agriculture on the Tradeoffs between Ecosystem Services and Economic Returns.

Science.gov (United States)

Kovacs, Kent; West, Grant

2016-01-01

An irrigated agricultural landscape experiencing groundwater overdraft generates economic returns and a suite of ecosystem services (in particular, groundwater supply, greenhouse gases reduction, and surface water quality). Alternative land cover choices indicate tradeoffs among the value of ecosystem services created and the economic returns. These tradeoffs are explored using efficiency frontiers that determine the least value in ecosystem services that must be given up to generate additional economic returns. Agricultural producers may switch to irrigation with surface water using on-farm reservoirs and tail water recovery systems in response to groundwater overdraft, and this has consequences for the bundle of ecosystem service values and economic returns achievable from the landscape. Planning that accounts for both ecosystem service value and economic returns can achieve more value for society, as does the adoption of reservoirs though lowering the costs of irrigation, increasing groundwater levels, and reducing fuel combustion and associated GHG emissions from groundwater pumping. Sensitivity analyses of per unit value of ecosystem services, crop prices, and the groundwater and water purification model parameters indicate tradeoff among ecosystems service values, such as the use of a high-end social cost of carbon ultimately lowers groundwater supply and water purification value by more than 15%.

The Influence of Groundwater Depletion from Irrigated Agriculture on the Tradeoffs between Ecosystem Services and Economic Returns.

Directory of Open Access Journals (Sweden)

Kent Kovacs

Full Text Available An irrigated agricultural landscape experiencing groundwater overdraft generates economic returns and a suite of ecosystem services (in particular, groundwater supply, greenhouse gases reduction, and surface water quality. Alternative land cover choices indicate tradeoffs among the value of ecosystem services created and the economic returns. These tradeoffs are explored using efficiency frontiers that determine the least value in ecosystem services that must be given up to generate additional economic returns. Agricultural producers may switch to irrigation with surface water using on-farm reservoirs and tail water recovery systems in response to groundwater overdraft, and this has consequences for the bundle of ecosystem service values and economic returns achievable from the landscape. Planning that accounts for both ecosystem service value and economic returns can achieve more value for society, as does the adoption of reservoirs though lowering the costs of irrigation, increasing groundwater levels, and reducing fuel combustion and associated GHG emissions from groundwater pumping. Sensitivity analyses of per unit value of ecosystem services, crop prices, and the groundwater and water purification model parameters indicate tradeoff among ecosystems service values, such as the use of a high-end social cost of carbon ultimately lowers groundwater supply and water purification value by more than 15%.

Quantifying uncertainty and trade-offs in resilience assessments

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Craig R. Allen

2018-03-01

Full Text Available Several frameworks have been developed to assess the resilience of social-ecological systems, but most require substantial data inputs, time, and technical expertise. Stakeholders and practitioners often lack the resources for such intensive efforts. Furthermore, most end with problem framing and fail to explicitly address trade-offs and uncertainty. To remedy this gap, we developed a rapid survey assessment that compares the relative resilience of social-ecological systems with respect to a number of resilience properties. This approach generates large amounts of information relative to stakeholder inputs. We targeted four stakeholder categories: government (policy, regulation, management, end users (farmers, ranchers, landowners, industry, agency/public science (research, university, extension, and NGOs (environmental, citizen, social justice in four North American watersheds, to assess social-ecological resilience through surveys. Conceptually, social-ecological systems are comprised of components ranging from strictly human to strictly ecological, but that relate directly or indirectly to one another. They have soft boundaries and several important dimensions or axes that together describe the nature of social-ecological interactions, e.g., variability, diversity, modularity, slow variables, feedbacks, capital, innovation, redundancy, and ecosystem services. There is no absolute measure of resilience, so our design takes advantage of cross-watershed comparisons and therefore focuses on relative resilience. Our approach quantifies and compares the relative resilience across watershed systems and potential trade-offs among different aspects of the social-ecological system, e.g., between social, economic, and ecological contributions. This approach permits explicit assessment of several types of uncertainty (e.g., self-assigned uncertainty for stakeholders; uncertainty across respondents, watersheds, and subsystems, and subjectivity in

Army ants dynamically adjust living bridges in response to a cost-benefit trade-off.

Science.gov (United States)

Reid, Chris R; Lutz, Matthew J; Powell, Scott; Kao, Albert B; Couzin, Iain D; Garnier, Simon

2015-12-08

The ability of individual animals to create functional structures by joining together is rare and confined to the social insects. Army ants (Eciton) form collective assemblages out of their own bodies to perform a variety of functions that benefit the entire colony. Here we examine ‟bridges" of linked individuals that are constructed to span gaps in the colony's foraging trail. How these living structures adjust themselves to varied and changing conditions remains poorly understood. Our field experiments show that the ants continuously modify their bridges, such that these structures lengthen, widen, and change position in response to traffic levels and environmental geometry. Ants initiate bridges where their path deviates from their incoming direction and move the bridges over time to create shortcuts over large gaps. The final position of the structure depended on the intensity of the traffic and the extent of path deviation and was influenced by a cost-benefit trade-off at the colony level, where the benefit of increased foraging trail efficiency was balanced by the cost of removing workers from the foraging pool to form the structure. To examine this trade-off, we quantified the geometric relationship between costs and benefits revealed by our experiments. We then constructed a model to determine the bridge location that maximized foraging rate, which qualitatively matched the observed movement of bridges. Our results highlight how animal self-assemblages can be dynamically modified in response to a group-level cost-benefit trade-off, without any individual unit's having information on global benefits or costs.

Ethical Perspective: Five Unacceptable Trade-offs on the Path to Universal Health Coverage

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Ole Frithjof Norheim

2015-11-01

Full Text Available This article discusses what ethicists have called “unacceptable trade-offs” in health policy choices related to universal health coverage (UHC. Since the fiscal space is constrained, trade-offs need to be made. But some trade-offs are unacceptable on the path to universal coverage. Unacceptable choices include, among other examples from low-income countries, to expand coverage for services with lower priority such as coronary bypass surgery before securing universal coverage for high-priority services such as skilled birth attendance and services for easily preventable or treatable fatal childhood diseases. Services of the latter kind include oral rehydration therapy for children with diarrhea and antibiotics for children with pneumonia. The article explains why such trade-offs are unfair and unacceptable even if political considerations may push in the opposite direction.

Ecosystem service trade-offs, perceived drivers, and sustainability in contrasting agroecosystems in central Mexico

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Carlos E. González-Esquivel

2015-03-01

Full Text Available The ability of agroecosystems to provide food ultimately depends on the regulating and supporting ecosystem services that underpin their functioning, such as the regulation of soil quality, water quality, soil erosion, pests, and pollinators. However, there are trade-offs between provisioning and regulating or supporting services, whose nature at the farm and plot scales is poorly understood. We analyzed data at the farm level for two agroecosystems with contrasting objectives in central Mexico: one aimed at staple crop production for self-subsistence and local markets, the other directed to a cash crop for export markets. Bivariate and multivariate trade-offs were analyzed for different crop management strategies (conventional, organic, traditional, crop rotation and their underpinning socioeconomic drivers. There was a clear trade-off between crop yield and soil quality in self-subsistence systems. However, other expected trade-offs between yields and soil quality did not always occur, likely because of the overall good soils of the region and the low to medium input profile of most farms. Trade-offs were highly dependent on farm-specific agricultural practices; organic, traditional, and rotation management systems generally showed smaller trade-offs between yield and soil quality, pest control, and biodiversity than did conventional management systems. Perceived drivers reported by farmers included increasing prices for cash crops, rising costs of inputs, and extreme climatic events (e.g., drought, hail, frost. Farmers did not identify the regulation of soil quality, water quality, soil erosion, pests, or pollinators as important constraints. Although acceptable yields could be maintained irrespective of key regulating and supporting services according to these perceptions, current levels of soil erosion and nutrient runoff are likely to have important negative effects at the watershed scale. Sustainability in both agroecosystems could be

Design trade-offs for homing missiles

Science.gov (United States)

Spencer, Allen; Moore, William

1992-05-01

Major design considerations, trade-offs and technology issues for future hypervelocity, anti-missile interceptors are presented in an overview format. Two classes of interceptors are considered: a low altitude interceptor using an active radar seeker for defense against tactical ballistic missiles (TBMs) and a higher altitude interceptor using a passive infra-red seeker for defense against ICBMs. Considerations are presented in the areas of mission requirements, seeker selection, aerodynamic and aerothermal environments, control systems, and guidance performance.

Beyond size–number trade-offs: clutch size as a maternal effect

Science.gov (United States)

Brown, Gregory P.; Shine, Richard

2009-01-01

Traditionally, research on life-history traits has viewed the link between clutch size and offspring size as a straightforward linear trade-off; the product of these two components is taken as a measure of maternal reproductive output. Investing more per egg results in fewer but larger eggs and, hence, offspring. This simple size–number trade-off has proved attractive to modellers, but our experimental studies on keelback snakes (Tropidonophis mairii, Colubridae) reveal a more complex relationship between clutch size and offspring size. At constant water availability, the amount of water taken up by a snake egg depends upon the number of adjacent eggs. In turn, water uptake affects hatchling size, and therefore an increase in clutch size directly increases offspring size (and thus fitness under field conditions). This allometric advantage may influence the evolution of reproductive traits such as growth versus reproductive effort, optimal age at female maturation, the body-reserve threshold required to initiate reproduction and nest-site selection (e.g. communal oviposition). The published literature suggests that similar kinds of complex effects of clutch size on offspring viability are widespread in both vertebrates and invertebrates. Our results also challenge conventional experimental methodologies such as split-clutch designs for laboratory incubation studies: by separating an egg from its siblings, we may directly affect offspring size and thus viability. PMID:19324614

Potential Trade-Offs between the Sustainable Development Goals in Coastal Bangladesh

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Craig W. Hutton

2018-04-01

Full Text Available The Sustainable Development Goals (SDGs are offered as a comprehensive strategy to guide and encourage sustainable development at multiple scales both nationally and internationally. Furthermore, through the development of indicators associated with each goal and sub-goal, the SDGs support the notion of monitoring, evaluation and adaptive management, underpinned by the aspirations of social justice, equity and transparency. As such, the ethical intention of the SDGs is well founded. However, possible conflicts and trade-offs between individual SDGs have received little attention. For example, SDGs relating to poverty (SDG 1, inequality (SDG 10, food security (SDG2, economic development (SDG 8 and life in water and on land (SDGs 14 and 15, are potentially competing in many circumstances. In a social–ecological context, policy support and formulation are increasingly adopting systems approaches, which analyse the complex interactions of system elements. Adopting such an approach in this work, the above SDGs are analysed for coastal Bangladesh. This demonstrates multiple potential trade-offs between the SDGs, including agricultural farming approaches in the light of poverty reduction, and between economic growth and environmental integrity as well as equity. To develop coherent and policy relevant socio-ecological strategies, appropriate decision frameworks need to be co-developed across the range of stakeholders and decision-makers. Integrated models have great potential to support such a process.

A trade-off relation between tilt and twist angle fluctuations in InN grown by RF-MBE

International Nuclear Information System (INIS)

Hashimoto, A.; Iwao, K.; Yamamoto, A.

2008-01-01

In the InN growth on sapphire substrates, it is difficult to control both of tilt and twist angle fluctuations at same time. It is necessary to understand initial growth stage such as the role of nitridation process to improve the mosaicity. Low-temperature nitridation technique brings the drastically improvement of the tilt angle fluctuation, although the twist angle fluctuation becomes worse. Such experimental results strongly indicate that there is some trade-off relation between the tilt and the twist angle fluctuations as a function of the nitridation condition such as the nitridation time. In this paper, we discuss about such trade-off relation in the direct growth of InN on the nitridation sapphire substrates and also propose a simple model of initial nitridation process to explain it. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Trade-off analysis of ecosystem service provision in nature networks

DEFF Research Database (Denmark)

Vogdrup-Schmidt, Mathias; Strange, Niels; Olsen, Søren Bøye

2017-01-01

We propose a spatial multi-criteria decision analysis approach as a value-focused decision support tool for evaluating land use change decisions affecting multiple ecosystem services. In an empirical case study concerned with creating a robust and interconnected network of natural areas in a Danish...... municipality, we first conduct a biophysical and economic baseline mapping of ecosystem services. We then construct a spatially explicit multi-criteria decision analysis model which is utilized to identify candidate areas for inclusion in the network. We define a base scenario for future land use in the area......, where all criteria have equal weight, and assess the outcome in terms of welfare economic benefits of ecosystem services and opportunity cost of reducing forest and agricultural production. As weights in multi-criteria analysis is innately a subjective task, we conduct a sensitivity analysis using four...

Vehicle emissions of short-lived and long-lived climate forcers: trends and tradeoffs.

Science.gov (United States)

Edwards, Morgan R; Klemun, Magdalena M; Kim, Hyung Chul; Wallington, Timothy J; Winkler, Sandra L; Tamor, Michael A; Trancik, Jessika E

2017-08-24

Evaluating technology options to mitigate the climate impacts of road transportation can be challenging, particularly when they involve a tradeoff between long-lived emissions (e.g., carbon dioxide) and short-lived emissions (e.g., methane or black carbon). Here we present trends in short- and long-lived emissions for light- and heavy-duty transport globally and in the U.S., EU, and China over the period 2000-2030, and we discuss past and future changes to vehicle technologies to reduce these emissions. We model the tradeoffs between short- and long-lived emission reductions across a range of technology options, life cycle emission intensities, and equivalency metrics. While short-lived vehicle emissions have decreased globally over the past two decades, significant reductions in CO 2 will be required by mid-century to meet climate change mitigation targets. This is true regardless of the time horizon used to compare long- and short-lived emissions. The short-lived emission intensities of some low-CO 2 technologies are higher than others, and thus their suitability for meeting climate targets depends sensitively on the evaluation time horizon. Other technologies offer low intensities of both short-lived emissions and CO 2 .

Phenotypic plasticity in the developmental integration of morphological trade-offs and secondary sexual trait compensation.

Science.gov (United States)

Tomkins, Joseph L; Kotiaho, Janne S; Lebas, Natasha R

2005-03-07

Trait exaggeration through sexual selection will tale place alongside other changes in phenotype. Exaggerated morphology might be compensated by parallel changes in traits that support, enhance or facilitate exaggeration: 'secondary sexual trait compensation' (SSTC). Alternatively, exaggeration might be realized at the expense of other traits through morphological trade-offs. For the most part, SSTC has only been examined interspecifically. For these phenomena to be important intraspecifically, the sexual trait must be developmentally integrated with the compensatory or competing trait. We studied developmental integration in two species with different development: the holometabolous beetle Onthophagus taurus and the hemimetabolous earwig Forficula auricularia. Male-dimorphic variation in trait exaggeration was exploited to expose both trade-offs and SSTC. We found evidence for morphological trade-offs in O. taurus, but no F. auricularia, supporting the notion that trade-offs are more likely in closed developmetal systems. However, we found these trade-offs were not limited solely to traits growing close together. Developmental integration of structures involved in SSTC were detected in both species. The developmental integration of SSTC was phenotypically plastic, such that the compensation for relatively larger sexual traits was greater in the exasperated male morphs. Evidence of intraspecific SSTC demands studies of the selective, genetic and developmental architecture of phenotypic integration.

Mapping synergies and trade-offs between energy and the Sustainable Development Goals

Science.gov (United States)

Fuso Nerini, Francesco; Tomei, Julia; To, Long Seng; Bisaga, Iwona; Parikh, Priti; Black, Mairi; Borrion, Aiduan; Spataru, Catalina; Castán Broto, Vanesa; Anandarajah, Gabrial; Milligan, Ben; Mulugetta, Yacob

2018-01-01

The 2030 Agenda for Sustainable Development—including 17 interconnected Sustainable Development Goals (SDGs) and 169 targets—is a global plan of action for people, planet and prosperity. SDG7 calls for action to ensure access to affordable, reliable, sustainable and modern energy for all. Here we characterize synergies and trade-offs between efforts to achieve SDG7 and delivery of the 2030 Agenda as a whole. We identify 113 targets requiring actions to change energy systems, and published evidence of relationships between 143 targets (143 synergies, 65 trade-offs) and efforts to achieve SDG7. Synergies and trade-offs exist in three key domains, where decisions about SDG7 affect humanity's ability to: realize aspirations of greater welfare and well-being; build physical and social infrastructures for sustainable development; and achieve sustainable management of the natural environment. There is an urgent need to better organize, connect and extend this evidence, to help all actors work together to achieve sustainable development.

Analysis of trade-offs between threats of invasion by nonnative brook trout (Salvelinus fontinalis) and intentional isolation for native westslope cutthroat trout (Oncorhynchus clarkii lewisi)

Science.gov (United States)

Peterson, D.P.; Rieman, B.E.; Dunham, J.B.; Fausch, K.D.; Young, M.K.

2008-01-01

Native salmonid fishes often face simultaneous threats from habitat fragmentation and invasion by nonnative trout species. Unfortunately, management actions to address one may create or exacerbate the other. A consistent decision process would include a systematic analysis of when and where intentional use or removal of barriers is the most appropriate action. We developed a Bayesian belief network as a tool for such analyses. We focused on native westslope cutthroat trout (Oncorhynchus clarkii lewisi) and nonnative brook trout (Salvelinus fontinalis) and considered the environmental factors influencing both species, their potential interactions, and the effects of isolation on the persistence of local cutthroat trout populations. The trade-offs between isolation and invasion were strongly influenced by size and habitat quality of the stream network to be isolated and existing demographic linkages within and among populations. An application of the model in several sites in western Montana (USA) showed the process could help clarify management objectives and options and prioritize conservation actions among streams. The approach can also facilitate communication among parties concerned with native salmonids, nonnative fish invasions, barriers and intentional isolation, and management of the associated habitats and populations. ?? 2008 NRC.

Panel discussion: In vivo pet modeling and data analysis

International Nuclear Information System (INIS)

Koeppe, R.A.

1991-01-01

Following the first afternoon session on in vivo PET modeling and data analysis, a panel assembled to discuss in greater detail some of the issues pertinent to the kinetic analysis of PET data. The discussion was opened with a comment on some of the diofficulties of PET imaging in the study of neurotransmitter and receptor systems, including resolution limitations, image distortions, and levels of nonspecific binding. Dr. Hutchins reiterated that the imaging distortions predicted by his simulation studies include both open-quotes scaleclose quotes and open-quotes shape open-quotes distortions. Then the panel discussed the issue of registration of functional (PET) and anatomic (MRI or CT) images. The use of an anatomic image as a road map or guide to where one is in the physiologic PET image is a very important part of performing PET studies. It is at least as important to align a dynamic PET sequence internally, from frame to frame, as it is to align the PET study to an anatomic study. If a dynamic imaging procedure will take 30-90 min or more, a method is needed to assure that the patient has not moved substantially during the procedure or that the movement can be accounted for. Several possibilities were discussed. The next topic considered the issue of model complexity versus model reduction. If a model is too complex, it cannot provide accurate estimates of the model parameters due to the lack of identifiability of individual parameters. Modeling approaches such as simplifying the model to two parameters and changing the experimental protocol to provide more information so model simplification is not necessary were discussed on the basis of the tradeoff between procedural complexity and quality of information

Drought-induced trans-generational tradeoff between stress tolerance and defence: consequences for range limits?

Science.gov (United States)

Alsdurf, Jacob D; Ripley, Tayler J; Matzner, Steven L; Siemens, David H

2013-01-01

Areas just across species range boundaries are often stressful, but even with ample genetic variation within and among range-margin populations, adaptation towards stress tolerance across range boundaries often does not occur. Adaptive trans-generational plasticity should allow organisms to circumvent these problems for temporary range expansion; however, range boundaries often persist. To investigate this dilemma, we drought stressed a parent generation of Boechera stricta (A.Gray) A. Löve & D. Löve, a perennial wild relative of Arabidopsis, representing genetic variation within and among several low-elevation range margin populations. Boechera stricta is restricted to higher, moister elevations in temperate regions where generalist herbivores are often less common. Previous reports indicate a negative genetic correlation (genetic tradeoff) between chemical defence allocation and abiotic stress tolerance that may prevent the simultaneous evolution of defence and drought tolerance that would be needed for range expansion. In growth chamber experiments, the genetic tradeoff became undetectable among offspring sib-families whose parents had been drought treated, suggesting that the stress-induced trans-generational plasticity may circumvent the genetic tradeoff and thus enable range expansion. However, the trans-generational effects also included a conflict between plastic responses (environmental tradeoff); offspring whose parents were drought treated were more drought tolerant, but had lower levels of glucosinolate toxins that function in defence against generalist herbivores. We suggest that either the genetic or environmental tradeoff between defence allocation and stress tolerance has the potential to contribute to range limit development in upland mustards.

State-independent error-disturbance trade-off for measurement operators

International Nuclear Information System (INIS)

Zhou, S.S.; Wu, Shengjun; Chau, H.F.

2016-01-01

In general, classical measurement statistics of a quantum measurement is disturbed by performing an additional incompatible quantum measurement beforehand. Using this observation, we introduce a state-independent definition of disturbance by relating it to the distinguishability problem between two classical statistical distributions – one resulting from a single quantum measurement and the other from a succession of two quantum measurements. Interestingly, we find an error-disturbance trade-off relation for any measurements in two-dimensional Hilbert space and for measurements with mutually unbiased bases in any finite-dimensional Hilbert space. This relation shows that error should be reduced to zero in order to minimize the sum of error and disturbance. We conjecture that a similar trade-off relation with a slightly relaxed definition of error can be generalized to any measurements in an arbitrary finite-dimensional Hilbert space.

Corticosterone manipulation reveals differences in hierarchical organization of multidimensional reproductive trade-offs in r-strategist and K-strategist females.

Science.gov (United States)

Lancaster, L T; Hazard, L C; Clobert, J; Sinervo, B R

2008-03-01

Life history trade-offs are often hierarchical with decisions at one level affecting lower level trade-offs. We investigated trade-off structure in female side-blotched lizards (Uta stansburiana), which exhibit two evolved strategies: yellow-throated females are K-strategists and orange-throated are r-strategists. Corticosterone treatment was predicted to differentially organize these females' reproductive decisions. Corticosterone-treated yellow females suppressed reproduction but survived well, and augmented egg mass without decreasing clutch size. Conversely, corticosterone enhanced mortality and reproductive rates in orange females, and increased egg mass only after lengthy exposure. Corticosterone did not affect post-laying condition, suggesting that corticosterone increased egg mass through enhanced energy acquisition (income breeding). Corticosterone enhanced survival of lightweight females, but decreased survival of heavy females, introducing a foraging vs. predation trade-off. We conclude that rather than being a direct, functional relationship, observed trade-offs between offspring size and number represent evolved differences in hierarchical organization of multidimensional trade-offs, particularly in response to stress.

"Do You Wanna Breathe or Eat?": Parent Perspectives on Child Health Consequences of Food Insecurity, Trade-Offs, and Toxic Stress.

Science.gov (United States)

Knowles, Molly; Rabinowich, Jenny; Ettinger de Cuba, Stephanie; Cutts, Diana Becker; Chilton, Mariana

2016-01-01

This study among 51 parents of young children under age four investigated how parents that report marginal, low and very low food security characterize how trade-offs associated with food insecurity affect parents' mental health and child well-being. We carried out 51 semi-structured audio-recorded interviews after participants responded to a survey regarding food security status and maternal depressive symptoms. Each interview was transcribed. Through a content analysis, we coded "meaning units" in each manuscript and organized them by themes in ATLAS.ti. Among participants reporting both food insecurity and depressive symptoms, we identified three primary areas of concern: trade-offs, mental health, and child well-being. Parents described how trade-offs associated with food insecurity have a profound relationship with their mental health and home environment that strongly affects young children. Descriptions of hardships include anxiety and depression related to overdue bills and shut-off notices, strains with housing costs, and safety. Parents described how their own frustration, anxiety, and depression related to economic hardship have a negative impact on their children's physical health, and their social and emotional development. Parents in food insecure households recognize that trade-offs between food and other basic necessities are associated with their personal stress and poor mental health that, in turn, affects their children's health and development. Partnerships between healthcare providers, policymakers, and parents are essential to successfully address and prevent the poor child health outcomes of toxic stress associated with food insecurity and poverty.

Tritium-containment systems: a tradeoff study

International Nuclear Information System (INIS)

Folkers, C.L.; Cena, R.J.

1978-01-01

Various design parameters are evaluated that affect the performance of tritium-containment systems for fusion reactors. Our study included a review of such parameters as tritium forms, impurities, catalysts, adsorbents, getters, and as low as reasonably achievable principles. We organized these schemes, which can be considered for treating either air or inert atmospheres, so one could easily make orderly choices and tradeoffs for optimum performance. The relationships examined involved purification-system decontamination factors, flow rates, recycling and leakage, and environmental losses

Valuing Treatments for Parkinson Disease Incorporating Process Utility: Performance of Best-Worst Scaling, Time Trade-Off, and Visual Analogue Scales

NARCIS (Netherlands)

Weernink, Marieke Geertruida Maria; Groothuis-Oudshoorn, Catharina Gerarda Maria; IJzerman, Maarten Joost; van Til, Janine Astrid

2016-01-01

Objective The objective of this study was to compare treatment profiles including both health outcomes and process characteristics in Parkinson disease using best-worst scaling (BWS), time trade-off (TTO), and visual analogue scales (VAS). Methods From the model comprising of seven attributes with

Heat-conserving postures hinder escape: a thermoregulation–predation trade-off in wintering birds

OpenAIRE

Jennie M. Carr; Steven L. Lima

2012-01-01

Wintering birds may conserve body heat by adopting postures with minimal leg exposure or significant ptiloerection. However, maximally heat-conserving postures may hinder a bird's ability to escape attack, leading to a trade-off between predation risk and thermoregulation. Such a trade-off implies that birds should use the most heat-conserving postures only at very cold temperatures. Feeding in a relatively low-risk environment should also facilitate the use of such heat-conserving postures. ...

Women's Benefits and Harms Trade-Offs in Breast Cancer Screening: Results from a Discrete-Choice Experiment.

Science.gov (United States)

Sicsic, Jonathan; Pelletier-Fleury, Nathalie; Moumjid, Nora

2018-01-01

Over the past decade, the benefits and harms balance of breast cancer (BC) screening has been widely debated. To elicit women's trade-offs between the benefits and harms of BC screening and to analyze the main determinants of these trade-offs. A discrete-choice experiment with seven attributes depicting BC screening programs including varying levels of BC mortality, overdiagnosis, and false-positive result was used. Eight hundred twelve women aged 40 to 74 years with no personal history of BC recruited by a survey institute and representative of the French general population (age, socioeconomic level, and geographical location) completed the discrete-choice experiment. Preference heterogeneity was investigated using generalized multinomial logit models from which individual trade-offs were derived, and their main determinants were assessed using generalized linear models. Screening acceptance rates under various benefits and harms ratios were simulated on the basis of the distribution of individual preferences. The women would be willing to accept on average 14.1 overdiagnosis cases (median = 9.6) and 47.8 false-positive results (median = 27.2) to avoid one BC-related death. After accounting for preference heterogeneity, less than 50% of women would be willing to accept 10 overdiagnosis cases for one BC-related death avoided. Screening acceptance rates were higher among women with higher socioeconomic level and lower among women with poor health. Women are sensitive to both the benefits and the harms of BC screening and their preferences are highly heterogeneous. Our study provides useful results for public health authorities and clinicians willing to improve their recommendations of BC screening on the basis of women's preferences. Copyright © 2018 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

Critical disease windows shaped by stress exposure alter allocation trade-offs between development and immunity.

Science.gov (United States)

Kirschman, Lucas J; Crespi, Erica J; Warne, Robin W

2018-01-01

Ubiquitous environmental stressors are often thought to alter animal susceptibility to pathogens and contribute to disease emergence. However, duration of exposure to a stressor is likely critical, because while chronic stress is often immunosuppressive, acute stress can temporarily enhance immune function. Furthermore, host susceptibility to stress and disease often varies with ontogeny; increasing during critical developmental windows. How the duration and timing of exposure to stressors interact to shape critical windows and influence disease processes is not well tested. We used ranavirus and larval amphibians as a model system to investigate how physiological stress and pathogenic infection shape development and disease dynamics in vertebrates. Based on a resource allocation model, we designed experiments to test how exposure to stressors may induce resource trade-offs that shape critical windows and disease processes because the neuroendocrine stress axis coordinates developmental remodelling, immune function and energy allocation in larval amphibians. We used wood frog larvae (Lithobates sylvaticus) to investigate how chronic and acute exposure to corticosterone, the dominant amphibian glucocorticoid hormone, mediates development and immune function via splenocyte immunohistochemistry analysis in association with ranavirus infection. Corticosterone treatments affected immune function, as both chronic and acute exposure suppressed splenocyte proliferation, although viral replication rate increased only in the chronic corticosterone treatment. Time to metamorphosis and survival depended on both corticosterone treatment and infection status. In the control and chronic corticosterone treatments, ranavirus infection decreased survival and delayed metamorphosis, although chronic corticosterone exposure accelerated rate of metamorphosis in uninfected larvae. Acute corticosterone exposure accelerated metamorphosis increased survival in infected larvae. Interactions

ExaSAT: An exascale co-design tool for performance modeling

International Nuclear Information System (INIS)

Unat, Didem; Chan, Cy; Zhang, Weiqun; Williams, Samuel; Bachan, John

2015-01-01

One of the emerging challenges to designing HPC systems is understanding and projecting the requirements of exascale applications. In order to determine the performance consequences of different hardware designs, analytic models are essential because they can provide fast feedback to the co-design centers and chip designers without costly simulations. However, current attempts to analytically model program performance typically rely on the user manually specifying a performance model. Here we introduce the ExaSAT framework that automates the extraction of parameterized performance models directly from source code using compiler analysis. The parameterized analytic model enables quantitative evaluation of a broad range of hardware design trade-offs and software optimizations on a variety of different performance metrics, with a primary focus on data movement as a metric. Finally, we demonstrate the ExaSAT framework’s ability to perform deep code analysis of a proxy application from the Department of Energy Combustion Co-design Center to illustrate its value to the exascale co-design process. ExaSAT analysis provides insights into the hardware and software trade-offs and lays the groundwork for exploring a more targeted set of design points using cycle-accurate architectural simulators.

Tradeoffs between battery energy capacity and stochastic optimal power management in plug-in hybrid electric vehicles

International Nuclear Information System (INIS)

Moura, Scott J.; Fathy, Hosam K.; Stein, Jeffrey L.; Callaway, Duncan S.

2010-01-01

Recent results in plug-in hybrid electric vehicle (PHEV) power management research suggest that battery energy capacity requirements may be reduced through proper power management algorithm design. Specifically, algorithms which blend fuel and electricity during the charge depletion phase using smaller batteries may perform equally to algorithms that apply electric-only operation during charge depletion using larger batteries. The implication of this result is that ''blended'' power management algorithms may reduce battery energy capacity requirements, thereby lowering the acquisition costs of PHEVs. This article seeks to quantify the tradeoffs between power management algorithm design and battery energy capacity, in a systematic and rigorous manner. Namely, we (1) construct dynamic PHEV models with scalable battery energy capacities, (2) optimize power management using stochastic control theory, and (3) develop simulation methods to statistically quantify the performance tradeoffs. The degree to which blending enables smaller battery energy capacities is evaluated as a function of both daily driving distance and energy (fuel and electricity) pricing. (author)

The collective construction of safety: a trade-off between "understanding" and "doing" in managing dynamic situations.

Science.gov (United States)

Cuvelier, L; Falzon, P

2015-03-01

This exploratory research aims to understand how teams organize themselves and collectively manage risky dynamic situations. The objective is to assess the plausibility of a model of a collective trade-off between "understanding" and "doing". The empirical study, conducted in the pediatric anesthesia service of a French university hospital, was supported by a "high fidelity" simulation with six teams. Data on the teams' behavior and on the verbal communications were collected through video recordings. The results highlight three modes for management of dynamic situations (determined management, cautious management, and overwhelmed management). These modes are related to the way in which teams manage their cognitive resources. More precisely, they are related to the teams' ability to collectively elaborate a trade-off between "understanding" and "doing". These results question existing perspectives on safety and suggest improvements in the design of crisis management training (concerning for example the recommendation of "calling for help"). Copyright © 2014 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Thermodynamics of accuracy in kinetic proofreading: dissipation and efficiency trade-offs

International Nuclear Information System (INIS)

Rao, Riccardo; Peliti, Luca

2015-01-01

The high accuracy exhibited by biological information transcription processes is due to kinetic proofreading, i.e. by a mechanism which reduces the error rate of the information-handling process by driving it out of equilibrium. We provide a consistent thermodynamic description of enzyme-assisted assembly processes involving competing substrates, in a master equation framework. We introduce and evaluate a measure of the efficiency based on rigorous non-equilibrium inequalities. The performance of several proofreading models are thus analyzed and the related time, dissipation and efficiency versus error trade-offs exhibited for different discrimination regimes. We finally introduce and analyze in the same framework a simple model which takes into account correlations between consecutive enzyme-assisted assembly steps. This work highlights the relevance of the distinction between energetic and kinetic discrimination regimes in enzyme-substrate interactions. (paper)

Linked sustainability challenges and trade-offs among fisheries, aquaculture and agriculture.

Science.gov (United States)

Blanchard, Julia L; Watson, Reg A; Fulton, Elizabeth A; Cottrell, Richard S; Nash, Kirsty L; Bryndum-Buchholz, Andrea; Büchner, Matthias; Carozza, David A; Cheung, William W L; Elliott, Joshua; Davidson, Lindsay N K; Dulvy, Nicholas K; Dunne, John P; Eddy, Tyler D; Galbraith, Eric; Lotze, Heike K; Maury, Olivier; Müller, Christoph; Tittensor, Derek P; Jennings, Simon

2017-09-01

Fisheries and aquaculture make a crucial contribution to global food security, nutrition and livelihoods. However, the UN Sustainable Development Goals separate marine and terrestrial food production sectors and ecosystems. To sustainably meet increasing global demands for fish, the interlinkages among goals within and across fisheries, aquaculture and agriculture sectors must be recognized and addressed along with their changing nature. Here, we assess and highlight development challenges for fisheries-dependent countries based on analyses of interactions and trade-offs between goals focusing on food, biodiversity and climate change. We demonstrate that some countries are likely to face double jeopardies in both fisheries and agriculture sectors under climate change. The strategies to mitigate these risks will be context-dependent, and will need to directly address the trade-offs among Sustainable Development Goals, such as halting biodiversity loss and reducing poverty. Countries with low adaptive capacity but increasing demand for food require greater support and capacity building to transition towards reconciling trade-offs. Necessary actions are context-dependent and include effective governance, improved management and conservation, maximizing societal and environmental benefits from trade, increased equitability of distribution and innovation in food production, including continued development of low input and low impact aquaculture.

Life history tradeoffs of pathogens and the treatment principle of antibiogenesis

Directory of Open Access Journals (Sweden)

Rui-An Wang

2017-09-01

Full Text Available There are no eternal individual lives so life continues by relaying with reproduction. Consequently, lifespan and fecundity are two essential genetic traits of life. The life history tradeoffs theory holds that there is an inverse relationship between lifespan and fecundity. This paper proposes two new concepts, i.e., “lifespan of pathogens” and treatment of infections by “antibiogenesis”. The lifespan of pathogens is the time limitation of those tiny lives just as other large creatures. Notably, the lifespan of bacterium is the time interval from the cell division by which it is produced to next division by then its life ends and transforms to two new lives, or dies. Antibiogenesis means inhibiting generation of new lives. By the principle of life history tradeoffs, the lifespan of pathogens determines the speed of their proliferations and consequently the modality of infection. The treatment principle of antibiogenesis requires the duration of treatment to be determined by the lifespan of infected pathogens. The life history tradeoffs theory and the two concepts are helpful to understanding the pathobiology and shaping the clinical aspects of infectious diseases.

Life-history constraints in grassland plant species: a growth-defence trade-off is the norm

Science.gov (United States)

E.M. Lind; E.T. Borer; E.W. Seabloom; P.B. Adler; J.D. Bakker; D.M. Blumenthal; M. Crawley; K.F. Davies; J. Firn; D.S. Gruner; S. Harpole; Y. Hautier; H. Hillebrand; J.M.H. Knops; B.A. Melbourne; B. Mortensen; A.C. Risch; M. Schuetz; C.J. Stevens; P.D. Wragg

2013-01-01

Plant growth can be limited by resource acquisition and defence against consumers, leading to contrasting trade-off possibilities. The competition-defence hypothesis posits a trade-off between competitive ability and defence against enemies (e.g. herbivores and pathogens). The growth-defence hypothesis suggests that strong competitors for nutrients are also defended...

Urban Forest Ecosystem Service Optimization, Tradeoffs, and Disparities

Science.gov (United States)

Bodnaruk, E.; Kroll, C. N.; Endreny, T. A.; Hirabayashi, S.; Yang, Y.

2014-12-01

Urban land area and the proportion of humanity living in cities is growing, leading to increased urban air pollution, temperature, and stormwater runoff. These changes can exacerbate respiratory and heat-related illnesses and affect ecosystem functioning. Urban trees can help mitigate these threats by removing air pollutants, mitigating urban heat island effects, and infiltrating and filtering stormwater. The urban environment is highly heterogeneous, and there is no tool to determine optimal locations to plant or protect trees. Using spatially explicit land cover, weather, and demographic data within biophysical ecosystem service models, this research expands upon the iTree urban forest tools to produce a new decision support tool (iTree-DST) that will explore the development and impacts of optimal tree planting. It will also heighten awareness of environmental justice by incorporating the Atkinson Index to quantify disparities in health risks and ecosystem services across vulnerable and susceptible populations. The study area is Baltimore City, a location whose urban forest and environmental justice concerns have been studied extensively. The iTree-DST is run at the US Census block group level and utilizes a local gradient approach to calculate the change in ecosystem services with changing tree cover across the study area. Empirical fits provide ecosystem service gradients for possible tree cover scenarios, greatly increasing the speed and efficiency of the optimization procedure. Initial results include an evaluation of the performance of the gradient method, optimal planting schemes for individual ecosystem services, and an analysis of tradeoffs and synergies between competing objectives.

Prioritization of Forest Restoration Projects: Tradeoffs between Wildfire Protection, Ecological Restoration and Economic Objectives

Directory of Open Access Journals (Sweden)

Kevin C. Vogler

2015-12-01

Full Text Available The implementation of US federal forest restoration programs on national forests is a complex process that requires balancing diverse socioecological goals with project economics. Despite both the large geographic scope and substantial investments in restoration projects, a quantitative decision support framework to locate optimal project areas and examine tradeoffs among alternative restoration strategies is lacking. We developed and demonstrated a new prioritization approach for restoration projects using optimization and the framework of production possibility frontiers. The study area was a 914,657 ha national forest in eastern Oregon, US that was identified as a national priority for restoration with the goal of increasing fire resiliency and sustaining ecosystem services. The results illustrated sharp tradeoffs among the various restoration goals due to weak spatial correlation of forest stressors and provisional ecosystem services. The sharpest tradeoffs were found in simulated projects that addressed either wildfire risk to the urban interface or wildfire hazard, highlighting the challenges associated with meeting both economic and fire protection goals. Understanding the nature of tradeoffs between restoration objectives and communicating them to forest stakeholders will allow forest managers to more effectively design and implement economically feasible restoration projects.

A Hybrid Secure Scheme for Wireless Sensor Networks against Timing Attacks Using Continuous-Time Markov Chain and Queueing Model.

Science.gov (United States)

Meng, Tianhui; Li, Xiaofan; Zhang, Sha; Zhao, Yubin

2016-09-28

Wireless sensor networks (WSNs) have recently gained popularity for a wide spectrum of applications. Monitoring tasks can be performed in various environments. This may be beneficial in many scenarios, but it certainly exhibits new challenges in terms of security due to increased data transmission over the wireless channel with potentially unknown threats. Among possible security issues are timing attacks, which are not prevented by traditional cryptographic security. Moreover, the limited energy and memory resources prohibit the use of complex security mechanisms in such systems. Therefore, balancing between security and the associated energy consumption becomes a crucial challenge. This paper proposes a secure scheme for WSNs while maintaining the requirement of the security-performance tradeoff. In order to proceed to a quantitative treatment of this problem, a hybrid continuous-time Markov chain (CTMC) and queueing model are put forward, and the tradeoff analysis of the security and performance attributes is carried out. By extending and transforming this model, the mean time to security attributes failure is evaluated. Through tradeoff analysis, we show that our scheme can enhance the security of WSNs, and the optimal rekeying rate of the performance and security tradeoff can be obtained.

A Framework for Similarity Search with Space-Time Tradeoffs using Locality Sensitive Filtering

DEFF Research Database (Denmark)

Christiani, Tobias Lybecker

2017-01-01

that satisfies certain locality-sensitivity properties, we can construct a dynamic data structure that solves the approximate near neighbor problem in $d$-dimensional space with query time $dn^{\\rho_q + o(1)}$, update time $dn^{\\rho_u + o(1)}$, and space usage $dn + n^{1 + \\rho_u + o(1)}$ where $n$ denotes......We present a framework for similarity search based on Locality-Sensitive Filtering~(LSF),generalizing the Indyk-Motwani (STOC 1998) Locality-Sensitive Hashing~(LSH) framework to support space-time tradeoffs. Given a family of filters, defined as a distribution over pairs of subsets of space...... the number of points in the data structure.The space-time tradeoff is tied to the tradeoff between query time and update time (insertions/deletions), controlled by the exponents $\\rho_q, \\rho_u$ that are determined by the filter family. \\\\ Locality-sensitive filtering was introduced by Becker et al. (SODA...

Muscle trade-offs in a power-amplified prey capture system.

Science.gov (United States)

Blanco, M Mendoza; Patek, S N

2014-05-01

Should animals operating at great speeds and accelerations use fast or slow muscles? The answer hinges on a fundamental trade-off: muscles can be maximally fast or forceful, but not both. Direct lever systems offer a straightforward manifestation of this trade-off, yet the fastest organisms use power amplification, not direct lever action. Power-amplified systems typically use slow, forceful muscles to preload springs, which then rapidly release elastic potential energy to generate high speeds and accelerations. However, a fast response to a stimulus may necessitate fast spring-loading. Across 22 mantis shrimp species (Stomatopoda), this study examined how muscle anatomy correlates with spring mechanics and appendage type. We found that muscle force is maximized through physiological cross-sectional area, but not through sarcomere length. Sit-and-wait predators (spearers) had the shortest sarcomere lengths (fastest contractions) and the slowest strike speeds. The species that crush shells (smashers) had the fastest speeds, most forceful springs, and longest sarcomeres. The origin of the smasher clade yielded dazzlingly high accelerations, perhaps due to the release from fast spring-loading for evasive prey capture. This study offers a new window into the dynamics of force-speed trade-offs in muscles in the biomechanical, comparative evolutionary framework of power-amplified systems. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

Functional dynamic factor models with application to yield curve forecasting

KAUST Repository

Hays, Spencer; Shen, Haipeng; Huang, Jianhua Z.

2012-01-01

resulted in a trade-off between goodness of fit and consistency with economic theory. To address this, herein we propose a novel formulation which connects the dynamic factor model (DFM) framework with concepts from functional data analysis: a DFM

Parents face quantity-quality trade-offs between reproduction and investment in offspring in Iceland.

Science.gov (United States)

Lynch, Robert Francis

2016-05-01

How to optimally allocate time, energy and investment in an effort to maximize one's reproductive success is a fundamental problem faced by all organisms. This effort is complicated when the production of each additional offspring dilutes the total resources available for parental investment. Although a quantity-quality trade-off between producing and investing in offspring has long been assumed in evolutionary biology, testing it directly in humans is difficult, partly owing to the long generation time of our species. Using data from an Icelandic genealogy (Íslendingabók) over two centuries, I address this issue and analyse the quantity-quality trade-off in humans. I demonstrate that the primary impact of parents on the fitness of their children is the result of resources and or investment, but not genes. This effect changes significantly across time, in response to environmental conditions. Overall, increasing reproduction has negative fitness consequences on offspring, such that each additional sibling reduces an individual's average lifespan and lifetime reproductive success. This analysis provides insights into the evolutionary conflict between producing and investing in children while also shedding light on some of the causes of the demographic transition.

Fitness trade-offs in pest management and intercropping with colour: an evolutionary framework and potential application.

Science.gov (United States)

Farkas, Timothy E

2015-10-01

An important modern goal of plant science research is to develop tools for agriculturalists effective at curbing yield losses to insect herbivores, but resistance evolution continuously threatens the efficacy of pest management strategies. The high-dose/refuge strategy has been employed with some success to curb pest adaptation, and has been shown to be most effective when fitness costs (fitness trade-offs) of resistance are high. Here, I use eco-evolutionary reasoning to demonstrate the general importance of fitness trade-offs for pest control, showing that strong fitness trade-offs mitigate the threat of pest adaptation, even if adaptation were to occur. I argue that novel pest management strategies evoking strong fitness trade-offs are the most likely to persist in the face of unbridled pest adaptation, and offer the manipulation of crop colours as a worked example of one potentially effective strategy against insect herbivores.

Making Trade-Offs Visible: Theoretical and Methodological Considerations about the Relationship between Dimensions and Institutions of Democracy and Empirical Findings

Directory of Open Access Journals (Sweden)

Hans-Joachim Lauth

2018-03-01

Full Text Available Whereas the measurement of the quality of democracy focused on the rough differentiation of democracies and autocracies in the beginning (e.g. Vanhanen, Polity, Freedom House, the focal point of newer instruments is the assessment of the quality of established democracies. In this context, tensions resp. trade-offs between dimensions of democracy are discussed as well (e.g. Democracy Barometer, Varieties of Democracy. However, these approaches lack a systematic discussion of trade-offs and they are not able to show trade-offs empirically. We address this research desideratum in a three-step process: Firstly, we propose a new conceptual approach, which distinguishes between two different modes of relationships between dimensions: mutual reinforcing effects and a give-and-take relationship (trade-offs between dimensions. By introducing our measurement tool, Democracy Matrix, we finally locate mutually reinforcing effects as well as trade-offs. Secondly, we provide a new methodological approach to measure trade-offs. While one measuring strategy captures the mutual reinforcing effects, the other strategy employs indicators, which serve to gauge trade-offs. Thirdly, we demonstrate empirical findings of our measurement drawing on the Varieties of Democracy dataset. Incorporating trade-offs into the measurement enables us to identify various profiles of democracy (libertarian, egalitarian and control-focused democracy via the quality of its dimensions.

No evidence of trade-offs in the evolution of sperm numbers and sperm size in mammals.

Science.gov (United States)

Tourmente, M; Delbarco Trillo, J; Roldan, E R S

2015-10-01

Post-copulatory sexual selection, in the form sperm competition, has influenced the evolution of several male reproductive traits. However, theory predicts that sperm competition would lead to trade-offs between numbers and size of spermatozoa because increased costs per cell would result in a reduction of sperm number if both traits share the same energetic budget. Theoretical models have proposed that, in large animals, increased sperm size would have minimal fitness advantage compared with increased sperm numbers. Thus, sperm numbers would evolve more rapidly than sperm size under sperm competition pressure. We tested in mammals whether sperm competition maximizes sperm numbers and size, and whether there is a trade-off between these traits. Our results showed that sperm competition maximizes sperm numbers in eutherian and metatherian mammals. There was no evidence of a trade-off between sperm numbers and sperm size in any of the two mammalian clades as we did not observe any significant relationship between sperm numbers and sperm size once the effect of sperm competition was taken into account. Maximization of both numbers and size in mammals may occur because each trait is crucial at different stages in sperm's life; for example size-determined sperm velocity is a key determinant of fertilization success. In addition, numbers and size may also be influenced by diverse energetic budgets required at different stages of sperm formation. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.

Dealing with trade-offs in destructive sampling designs for occupancy surveys.

Directory of Open Access Journals (Sweden)

Stefano Canessa

Full Text Available Occupancy surveys should be designed to minimise false absences. This is commonly achieved by increasing replication or increasing the efficiency of surveys. In the case of destructive sampling designs, in which searches of individual microhabitats represent the repeat surveys, minimising false absences leads to an inherent trade-off. Surveyors can sample more low quality microhabitats, bearing the resultant financial costs and producing wider-spread impacts, or they can target high quality microhabitats were the focal species is more likely to be found and risk more severe impacts on local habitat quality. We show how this trade-off can be solved with a decision-theoretic approach, using the Millewa Skink Hemiergis millewae from southern Australia as a case study. Hemiergis millewae is an endangered reptile that is best detected using destructive sampling of grass hummocks. Within sites that were known to be occupied by H. millewae, logistic regression modelling revealed that lizards were more frequently detected in large hummocks. If this model is an accurate representation of the detection process, searching large hummocks is more efficient and requires less replication, but this strategy also entails destruction of the best microhabitats for the species. We developed an optimisation tool to calculate the minimum combination of the number and size of hummocks to search to achieve a given cumulative probability of detecting the species at a site, incorporating weights to reflect the sensitivity of the results to a surveyor's priorities. The optimisation showed that placing high weight on minimising volume necessitates impractical replication, whereas placing high weight on minimising replication requires searching very large hummocks which are less common and may be vital for H. millewae. While destructive sampling methods are sometimes necessary, surveyors must be conscious of the ecological impacts of these methods. This study provides a

Ecosystem service trade-offs across global contexts and scales

Directory of Open Access Journals (Sweden)

Jeannine Cavender-Bares

2015-03-01

Full Text Available Meeting human needs while sustaining the planet's life support systems is the fundamental challenge of our time. What role sustenance of biodiversity and contrasting ecosystem services should play in achieving a sustainable future varies along philosophical, cultural, institutional, societal, and governmental divisions. Contrasting biophysical constraints and perspectives on human well-being arise both within and across countries that span the tropics and temperate zone. Direct sustenance of livelihoods from ecosystem services in East Africa contrasts with the complex and diverse relationships with the land in Mexico and the highly monetary-based economy of the United States. Lack of understanding of the contrasting contexts in which decision-making about trade-offs occurs creates impediments to collective global efforts to sustain the Earth's life support systems. While theoretical notions of the goals of sustainability science seek a unified path forward, realities on the ground present challenges. This Special Feature seeks to provide both an analytical framework and a series of case studies to illuminate impediments posed to sustainability by contrasting biophysical constraints and human perspectives on what should be sustained. The contributors aim to clarify the trade-offs posed to human welfare in sustaining biodiversity and ecosystem services and the challenges in managing for a sustainable future in which human well-being is not compromised as compared to today. Our goal is to provide novel insights on how sustainability can be achieved internationally through exploration of constraints, trade-offs, and human values examined at multiple scales, and across geographic regions from a range of cultural perspectives.

Multi-objective Analysis for a Sequencing Planning of Mixed-model Assembly Line

Science.gov (United States)

Shimizu, Yoshiaki; Waki, Toshiya; Yoo, Jae Kyu

Diversified customer demands are raising importance of just-in-time and agile manufacturing much more than before. Accordingly, introduction of mixed-model assembly lines becomes popular to realize the small-lot-multi-kinds production. Since it produces various kinds on the same assembly line, a rational management is of special importance. With this point of view, this study focuses on a sequencing problem of mixed-model assembly line including a paint line as its preceding process. By taking into account the paint line together, reducing work-in-process (WIP) inventory between these heterogeneous lines becomes a major concern of the sequencing problem besides improving production efficiency. Finally, we have formulated the sequencing problem as a bi-objective optimization problem to prevent various line stoppages, and to reduce the volume of WIP inventory simultaneously. Then we have proposed a practical method for the multi-objective analysis. For this purpose, we applied the weighting method to derive the Pareto front. Actually, the resulting problem is solved by a meta-heuristic method like SA (Simulated Annealing). Through numerical experiments, we verified the validity of the proposed approach, and discussed the significance of trade-off analysis between the conflicting objectives.

ARCHITECT: The architecture-based technology evaluation and capability tradeoff method

Science.gov (United States)

Griendling, Kelly A.

creation of DoDAF products forward in the defense acquisition process, and (3) using DoDAF products for more than documentation by integrating them into the problem definition and analysis of alternatives phases and applying executable architecting. This research proposes and demonstrates the plausibility of a prescriptive methodology for developing executable DoDAF products which will explicitly support decision-making in the early phases of JCIDS. A set of criteria by which CBAs should be judged is proposed, and the methodology is developed with these criteria in mind. The methodology integrates existing tools and techniques for systems engineering and system of systems engineering with several new modeling and simulation tools and techniques developed as part of this research to fill gaps noted in prior CBAs. A suppression of enemy air defenses (SEAD) mission is used to demonstrate the ap- plication of ARCHITECT and to show the plausibility of the approach. For the SEAD study, metrics are derived and a gap analysis is performed. The study then identifies and quantitatively compares system and operational architecture alternatives for performing SEAD. A series of down-selections is performed to identify promising architectures, and these promising solutions are subject to further analysis where the impacts of force structure and network structure are examined. While the numerical results of the SEAD study are notional and could not be applied to an actual SEAD CBA, the example served to highlight many of the salient features of the methodology. The SEAD study presented enabled pre-Milestone A tradeoffs to be performed quantitatively across a large number of architectural alternatives in a traceable and repeatable manner. The alternatives considered included variations on operations, systems, organizational responsibilities (through the assignment of systems to tasks), network (or collaboration) structure, interoperability level, and force structure. All of the

Second-generation mobile satellite system. A conceptual design and trade-off study

Science.gov (United States)

Sue, M. K.; Park, Y. H.

1985-01-01

In recent years, interest has grown in the mobile satellite (MSAT) system, a satellite-based communications system capable of providing integrated voice and data services to a large number of users. To explore the potential of a commercial mobile satellite system (MSS) beyond the horizon of the first generation, using technologies of the 1990's and to assist MSAT-X in directing its efforts, a conceptual design has been performed for a second-generation system to be launched around the mid-1990's. The design goal is to maximize the number of satellite channels and/or minimize the overall life-cycle cost, subject to the constraint of utilizing a commercial satellite bus with minimum modifications. To provide an optimal design, a series of trade-offs are performed, including antenna sizing, feed configurations, and interference analysis. Interference is a serious problem for MSAT and often an overlapping feed design is required to reduce interbeam interference. The trade-off studies will show that a simple non-overlapping feed is sufficient for the second-generation system, thus avoiding the need for the complicated beam-forming network that is associated with the overlapping feed designs. In addition, a system that operates at L-band, an alternative frequency band that is being considered by some for possible MSAT applications, is also presented.

Soil management shapes ecosystem service provision and trade-offs in agricultural landscapes.

Science.gov (United States)

Tamburini, Giovanni; De Simone, Serena; Sigura, Maurizia; Boscutti, Francesco; Marini, Lorenzo

2016-08-31

Agroecosystems are principally managed to maximize food provisioning even if they receive a large array of supporting and regulating ecosystem services (ESs). Hence, comprehensive studies investigating the effects of local management and landscape composition on the provision of and trade-offs between multiple ESs are urgently needed. We explored the effects of conservation tillage, nitrogen fertilization and landscape composition on six ESs (crop production, disease control, soil fertility, water quality regulation, weed and pest control) in winter cereals. Conservation tillage enhanced soil fertility and pest control, decreased water quality regulation and weed control, without affecting crop production and disease control. Fertilization only influenced crop production by increasing grain yield. Landscape intensification reduced the provision of disease and pest control. We also found tillage and landscape composition to interactively affect water quality regulation and weed control. Under N fertilization, conventional tillage resulted in more trade-offs between ESs than conservation tillage. Our results demonstrate that soil management and landscape composition affect the provision of several ESs and that soil management potentially shapes the trade-offs between them. © 2016 The Author(s).

Defensive traits exhibit an evolutionary trade-off and drive diversification in ants.

Science.gov (United States)

Blanchard, Benjamin D; Moreau, Corrie S

2017-02-01

Evolutionary biologists have long predicted that evolutionary trade-offs among traits should constrain morphological divergence and species diversification. However, this prediction has yet to be tested in a broad evolutionary context in many diverse clades, including ants. Here, we reconstruct an expanded ant phylogeny representing 82% of ant genera, compile a new family-wide trait database, and conduct various trait-based analyses to show that defensive traits in ants do exhibit an evolutionary trade-off. In particular, the use of a functional sting negatively correlates with a suite of other defensive traits including spines, large eye size, and large colony size. Furthermore, we find that several of the defensive traits that trade off with a sting are also positively correlated with each other and drive increased diversification, further suggesting that these traits form a defensive suite. Our results support the hypothesis that trade-offs in defensive traits significantly constrain trait evolution and influence species diversification in ants. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

On capacity tradeoffs in secure DS-CDMA packet communications with QOS constraints

International Nuclear Information System (INIS)

Sattar, F.; Mufti, M.

2012-01-01

This paper presents a mathematical framework for analysis of effect of counter mode (CTR) encryption on the traffic capacity of packet communication systems based on direct-sequence, code-division, multiple-access (DS-CDMA). We specify QoS constraints in terms of minimum acceptable mean opinion score (MOS) of voice payload, maximum permissible resource utilization for CTR-mode re-keying and DS-CDMA processing gain. We quantify the trade-offs in system capacity as a function of these constraints. Results show that application of CTR encryption causes error expansion and respecting the QoS constraints while satisfying the desired encryption parameters results in reduction of traffic capacity. (author)

Effect of primary user traffic on sensing-throughput tradeoff for cognitive radios

KAUST Repository

Tang, Liang

2011-04-01

The effect of the primary user traffic on the performance of the secondary network is investigated for the tradeoff between the sensing quality and the achievable throughput. Numerical results show that the actual secondary network performance when the random departure or arrival of the primary user is taken into account is worse than the predicted secondary network performance in the literature assuming constant occupancy state of the primary user. The degree of degradation depends on the traffic intensity as well as the received signal-to-noise ratio at the secondary user. Also, unlike the conventional model where the occupancy state of the primary user is assumed constant, the optimal sensing time in the new model varies for different primary channel conditions when the primary user traffic is considered. © 2011 IEEE.

When we cannot have it all: Ecosystem services trade-offs in the context of spatial planning

NARCIS (Netherlands)

Turkelboom, Francis; Leone, Michael; Jacobs, Sander; Kelemen, Eszter; García-Llorente, Marina; Baró, Francesc; Termansen, Mette; Barton, David N.; Berry, Pam; Stange, Erik; Thoonen, Marijke; Kalóczkai, Ágnes; Vadineanu, Angheluta; Castro, Antonio J.; Czúcz, Bálint; Röckmann, Christine; Wurbs, Daniel; Odee, David; Preda, Elena; Gómez-Baggethun, Erik; Rusch, Graciela M.; Pastur, Guillermo Martínez; Palomo, Ignacio; Dick, Jan; Casaer, Jim; Dijk, Van Jiska; Priess, Joerg A.; Langemeyer, Johannes; Mustajoki, Jyri; Kopperoinen, Leena; Baptist, Martin J.; Peri, Pablo Luis; Mukhopadhyay, Raktima; Aszalós, Réka; Roy, S.B.; Luque, Sandra; Rusch, Verónica

2018-01-01

Spatial planning has to deal with trade-offs between various stakeholders’ wishes and needs as part of planning and management of landscapes, natural resources and/or biodiversity. To make ecosystem services (ES) trade-off research more relevant for spatial planning, we propose an analytical

Financing Investment: The Cost Trade-Off

DEFF Research Database (Denmark)

Hirth, Stefan; Flor, Christian Riis

Intuition suggests that corporate investment should be decreasing in financing constraints. We show that even when financing is obtained using a standard debt contract and there is symmetric information between the firm and outside investors, the relation is actually U-shaped. We thus provide a new...... theoretical explanation for the recent empirical findings of Cleary et al. (2007). We split up the endogenously implied financing costs and propose a trade-off between expected liquidation costs and second-best investment costs. For rather unconstrained firms, the risk of costly liquidation dominates the cost...

Getting a Cohesive Answer from a Common Start: Scalable Multidisciplinary Analysis through Transformation of a Systems Model

Science.gov (United States)

Cole, Bjorn; Chung, Seung

2012-01-01

One of the challenges of systems engineering is in working multidisciplinary problems in a cohesive manner. When planning analysis of these problems, system engineers must trade between time and cost for analysis quality and quantity. The quality often correlates with greater run time in multidisciplinary models and the quantity is associated with the number of alternatives that can be analyzed. The trade-off is due to the resource intensive process of creating a cohesive multidisciplinary systems model and analysis. Furthermore, reuse or extension of the models used in one stage of a product life cycle for another is a major challenge. Recent developments have enabled a much less resource-intensive and more rigorous approach than hand-written translation scripts between multi-disciplinary models and their analyses. The key is to work from a core systems model defined in a MOF-based language such as SysML and in leveraging the emerging tool ecosystem, such as Query/View/Transformation (QVT), from the OMG community. SysML was designed to model multidisciplinary systems. The QVT standard was designed to transform SysML models into other models, including those leveraged by engineering analyses. The Europa Habitability Mission (EHM) team has begun to exploit these capabilities. In one case, a Matlab/Simulink model is generated on the fly from a system description for power analysis written in SysML. In a more general case, symbolic analysis (supported by Wolfram Mathematica) is coordinated by data objects transformed from the systems model, enabling extremely flexible and powerful design exploration and analytical investigations of expected system performance.

Understanding trade-offs between development and resources

CSIR Research Space (South Africa)

Ngwadla, Xolisa

2017-01-01

Full Text Available stream_source_info Ngwadla_CSIR2017.pdf.txt stream_content_type text/plain stream_size 4104 Content-Encoding UTF-8 stream_name Ngwadla_CSIR2017.pdf.txt Content-Type text/plain; charset=UTF-8 UNDERSTANDING TRADE... feedstock + production aspects • Are there limits to growth? WHY UNDERSTAND RESOURCE TRADE-OFFS WITH INDUSTRIAL DEVELOPMENT? UNEMPLOYMENT - 24% in 2011 - 27% in 2016 INEQUALITY - Gini Coefficient: - 0,69 in 2011 - 0,68 in 2015...

Uses And Characteristics Of Dynamic Tradeoff Evaluation

Science.gov (United States)

Schwuttke, Ursula M.

1995-01-01

Report discusses basic concepts, some applications, and performance characteristics of dynamic tradeoff evaluation (DTE). Basic concepts of DTE also described in "Dynamic Restructuring of Problems in Artificial Intelligence" (NPO-18488). DTE is method of enhancing real-time performance of artificial-intelligence system such as might be used to monitor data from multiple sensors in factory, aircraft, spacecraft, or other complex system of equipment. Report presents evaluation of DTE as applied to spacecraft-monitoring problems.

A trade-off study revealing nested timescales of constraint

NARCIS (Netherlands)

Wijnants, M.L.; Cox, R.F.A; Hasselman, F.; Bosman, A. M. T.; Van Orden, G.

2012-01-01

This study investigates human performance in a cyclic Fitts task at three different scales of observation, either in the presence (difficult condition) or in the absence (easy condition) of a speed–accuracy trade-off. At the fastest scale, the harmonicity of the back and forth movements, which

Desired, Perceived, and Achieved Sustainability: Trade-Offs in Strategic and Operational Packaging Development

Directory of Open Access Journals (Sweden)

Bjorn de Koeijer

2017-10-01

Full Text Available The alignment of the strategic and the operational level of packaging development in relation to the integration of sustainability is not addressed extensively in current research. This paper aims to address this, by focusing on the decision-making interrelations of key actors (marketing and packaging development within multidisciplinary product-packaging development teams. The research is conducted by means of a qualitative approach, consisting of semi-structured interviews with individual packaging development team members, complemented with a newly developed visualization tool. The research builds upon eight cases within brand owners, packaging material suppliers and packaging development consultants. The main findings of the study include the decision-making trade-offs between sustainability considerations and other project indicators, such as costs, time-to-market and technical challenges. These trade-offs are linked to the strategic and operational roles of key actors, and to internal and external factors influencing sustainable development processes. This research’s contribution is to address the alignment of the strategic and the operational levels of sustainable packaging development, in relation to (1 decision making and interrelations within multidisciplinary development teams; and (2 the relevance of development-influencing factors. This provides opportunities for further development of sustainable packaging models and tools, in order to align the strategic and operational level of development.

Do human parents face a quantity-quality tradeoff?: evidence from a Shuar community.

Science.gov (United States)

Hagen, Edward H; Barrett, H Clark; Price, Michael E

2006-07-01

A number of evolutionary theories of human life history assume a quantity-quality tradeoff for offspring production: parents with fewer offspring can have higher biological fitness than those with more. Direct evidence for such a tradeoff, however, is mixed. We tested this assumption in a community of Ecuadorian Shuar hunter-horticulturalists, using child anthropometry as a proxy for fitness. We measured the impact of household consumer/producer (CP) ratio on height, weight, skinfold thicknesses, and arm and calf circumferences of 85 children and young adults. To control for possible "phenotypic" correlates that might mask the effect of CP ratio on anthropometry, we also measured household garden productivity, wealth, and social status. Regression models of the age-standardized variables indicated a significant negative impact of CP ratio on child growth and nutrition. The age-standardized height and weight of children in households with the largest CP ratio (10) were 1.38 and 1.44 standard deviations, respectively, below those of children in households with the smallest CP ratio (2). Surprisingly, garden productivity, wealth, and status had little to no effect on the fitness proxies. There was, however, an interesting and unexpected interaction between status and sex: for females, but not males, higher father status correlated significantly with higher values on the proxies.

Fundamental rate-loss trade-off for the quantum internet.

Science.gov (United States)

Azuma, Koji; Mizutani, Akihiro; Lo, Hoi-Kwong

2016-11-25

The quantum internet holds promise for achieving quantum communication-such as quantum teleportation and quantum key distribution (QKD)-freely between any clients all over the globe, as well as for the simulation of the evolution of quantum many-body systems. The most primitive function of the quantum internet is to provide quantum entanglement or a secret key to two points efficiently, by using intermediate nodes connected by optical channels with each other. Here we derive a fundamental rate-loss trade-off for a quantum internet protocol, by generalizing the Takeoka-Guha-Wilde bound to be applicable to any network topology. This trade-off has essentially no scaling gap with the quantum communication efficiencies of protocols known to be indispensable to long-distance quantum communication, such as intercity QKD and quantum repeaters. Our result-putting a practical but general limitation on the quantum internet-enables us to grasp the potential of the future quantum internet.

Ecosystem services trade-offs and determinants in China's Yangtze River Economic Belt from 2000 to 2015.

Science.gov (United States)

Xu, Xibao; Yang, Guishan; Tan, Yan; Liu, Jingping; Hu, Huizhi

2018-09-01

Ecosystem services (ES) play an important role in sustaining ecological security, sustainable development and human well-being. This study investigates spatio-temporal changes in five key ES in the Yangtze River Economic Belt of China in 2000-2015-water conservation (WC), soil retention (SR), carbon sequestration (CS), biodiversity conservation (BC) and food supply (FS), by applying three ecological models (InVEST, RUSLE, CASA). Employing scenario simulations, the study quantifies distinct effects of significant factors on ES changes. Using spatial overlapping and Spearman's rank correlation respectively, the study distinguishes spatial patterns of synergies and trade-offs between five ES at the grid and city-scales. The results show that CS, FS, WC and SR presented an overall upward trend, increasing by 22.7%, 16.9%, 6.4% and 4.7%, respectively, while BC remained steady with a marginal degradation. Change in these five ES exhibited dramatic spatial heterogeneity. Across 131 cities, 98.5% of which increased in CS, 87.7% in WC, 68.5% in FS, and 53.1% in SR, while more than half experienced slight degradation in BC. There is high heterogeneity and a great diversity among spatial distributions of ES synergies and trade-offs, which is largely dependent on ES pairs and spatial patterns of land use. Land use/land cover change was the dominant force driving changes in SR, BC and CS, while meteorological factors exhibited a greater effect on WS change than land use/land cover change. The paper examines the synergies between WC-SR, CS-BC and BC-FS on the city level, while WC-BC exhibits significant trade-offs, and no significant relationships for other ES pairs. It is imperative that ES trade-offs at different scales are incorporated to strengthen ecological protection and management policies in project implementation, maintaining ES within vital regions in China. More sophisticated methods and more ES indicators need to be incorporated to enhance the robustness and

Mortality tradeoff between air quality and skin cancer from changes in stratospheric ozone

Science.gov (United States)

Eastham, Sebastian D.; Keith, David W.; Barrett, Steven R. H.

2018-03-01

Skin cancer mortality resulting from stratospheric ozone depletion has been widely studied. Similarly, there is a deep body of literature on surface ozone and its health impacts, with modeling and observational studies demonstrating that surface ozone concentrations can be increased when stratospheric air mixes to the Earth’s surface. We offer the first quantitative estimate of the trade-off between these two effects, comparing surface air quality benefits and UV-related harms from stratospheric ozone depletion. Applying an idealized ozone loss term in the stratosphere of a chemistry-transport model for modern-day conditions, we find that each Dobson unit of stratospheric ozone depletion results in a net decrease in the global annual mortality rate of ~40 premature deaths per billion population (d/bn/DU). The impacts are spatially heterogeneous in sign and magnitude, composed of a reduction in premature mortality rate due to ozone exposure of ~80 d/bn/DU concentrated in Southeast Asia, and an increase in skin cancer mortality rate of ~40 d/bn/DU, mostly in Western Europe. This is the first study to quantify air quality benefits of stratospheric ozone depletion, and the first to find that marginal decreases in stratospheric ozone around modern-day values could result in a net reduction in global mortality due to competing health impact pathways. This result, which is subject to significant methodological uncertainty, highlights the need to understand the health and environmental trade-offs involved in policy decisions regarding anthropogenic influences on ozone chemistry over the 21st century.

Combining integrated models and participatory methods to quantify water and agricultural trade-offs linked to different rural development scenarios

Science.gov (United States)

Rivas, David; Willaarts, Barbara; García, Ángel de Miguel; Tarquis, Ana Maria

2017-04-01

This study explores the water and agricultural tradeoffs linked to three different rural development scenarios in the Cega-Eresma-Adaja basin (CEA) in Central Spain. Agriculture is a key socioeconomic activity in CEA, and nearly 44% of the basin is devoted to croplands and pastures. Irrigated agriculture accounts for 12% of the cropland area and is currently using over 84% of available water resources. To define the three scenarios for CEA, we conducted a workshop with local stakeholders to infer how contrasting evolutions of EU agricultural, water and environmental policies could affect the local land use and agricultural management using participatory mapping techniques. The three scenarios reflect 1) a business as usual (BAU) rural development; 2) a land sharing strategy (LSH); and 3) a land sparing (LSP) situation. The integrated Soil Water Assessment Tool (SWAT) was used to model the changes in water use (hm^3/year) and agricultural productivity (ton/year) under each scenario. To account for changes in agricultural land use and management, the model integrates a large set of agricultural patterns obtained from combining high resolution remote sensing images (20m x 20m) for the years 2011-2015, agricultural productivity from survey by municipality and land use information obtained from the national map SIOSE2011 (1:50.000). Model calibration and sensitivity analysis were performed using SWAT-CUP/SUFI2 The period of the years 2005 to 2008 were used for parameter calibration and validation period extending between 2009 and 2014. The predicted daily streamflow presents a correlation coefficient of 0.76 and a NS coefficient of 0.81. The preliminary results reveal that under a BAU and a LSP scenario agricultural production and water demand will increase significantly (>25%) despite the improvements in water use efficiency and agricultural productivity. Under these scenarios, allocated water is likely to exceed the natural renewable water resources compromising the

Trade-offs between ecosystem services and alternative pathways toward sustainability in a tropical dry forest region

Directory of Open Access Journals (Sweden)

Francisco Mora

2016-12-01

Full Text Available The design of strategies aimed at sustainable resource management requires an understanding of the trade-offs between the ecosystem services at stake, to determine appropriate ways in which to navigate them. We assess trade-offs between forage production for cattle ranching and the maintenance of carbon stocks or tree diversity in a Mexican tropical dry forest. Trade-offs between pairs of services were assessed by identifying their efficiency frontiers at both site and landscape scales. We also estimated service outcomes under current and hypothetical land-management conditions. We found stark trade-offs between fodder and carbon stocks and between fodder and tree species richness at the site scale. At the landscape scale, the efficiency frontier was concave, with a much less pronounced trade-off in the fodder-species richness case. Our estimates of current service supply levels showed a reduction of 18-21% for C stock and 41-43% for fodder biomass, relative to the maximum feasible values along the efficiency frontier. Choice of the optimum management strategy to reduce such inefficiency depended on deforestation level: secondary forest regeneration was most suitable when deforestation is low, whereas increased fodder productivity in the pastures is best when deforestation is high. Pasture enrichment with forage trees and secondary forest growth are potential management alternatives for achieving sustainability given the range of enabling ecological factors and to balance ecological and social sustainability given the requirements and preferences of local stakeholders. Given that analogous trade-offs are found across the tropics, this work contributes to reconciling tropical forest maintenance and its use for sustainable rural livelihoods.

Excess heat from kraft pulp mills: Trade-offs between internal and external use in the case of Sweden-Part 2: Results for future energy market scenarios

International Nuclear Information System (INIS)

Joensson, Johanna; Svensson, Inger-Lise; Berntsson, Thore; Moshfegh, Bahram

2008-01-01

In this paper the trade-off between internal and external use of excess heat from a kraft pulp mill is investigated for four different future energy market scenarios. The work follows the methodology described in Svensson et al. [2008. Excess heat from kraft pulp mills: trade-offs between internal and external use in the case of Sweden-Part 1: methodology. Energy Policy, submitted for publication], where a systematic approach is proposed for investigating the potential for profitable excess heat cooperation. The trade-off is analyzed by economic optimization of an energy system model consisting of a pulp mill and an energy company (ECO). In the model, investments can be made, which increase the system's energy efficiency by utilization of the mill's excess heat, as well as investments that increase the electricity production. The results show that the trade-off depends on energy market prices, the district heating demand and the type of existing heat production. From an economic point of view, external use of the excess heat is preferred for all investigated energy market scenarios if the mill is studied together with an ECO with a small heat load. For the cases with medium or large district heating loads, the optimal use of excess heat varies with the energy market price scenarios. However, from a CO 2 emissions perspective, external use is preferred, giving the largest reduction of global emissions in most cases

A hybrid Bayesian network approach for trade-offs between environmental flows and agricultural water using dynamic discretization

Science.gov (United States)

Xue, Jie; Gui, Dongwei; Lei, Jiaqiang; Sun, Huaiwei; Zeng, Fanjiang; Feng, Xinlong

2017-12-01

Agriculture and the eco-environment are increasingly competing for water. The extension of intensive farmland for ensuring food security has resulted in excessive water exploitation by agriculture. Consequently, this has led to a lack of water supply in natural ecosystems. This paper proposes a trade-off framework to coordinate the water-use conflict between agriculture and the eco-environment, based on economic compensation for irrigation stakeholders. A hybrid Bayesian network (HBN) is developed to implement the framework, including: (a) agricultural water shortage assessments after meeting environmental flows; (b) water-use tradeoff analysis between agricultural irrigation and environmental flows using the HBN; and (c) quantification of the agricultural economic compensation for different irrigation stakeholders. The constructed HBN is computed by dynamic discretization, which is a more robust and accurate propagation algorithm than general static discretization. A case study of the Qira oasis area in Northwest China demonstrates that the water trade-off based on economic compensation depends on the available water supply and environmental flows at different levels. Agricultural irrigation water extracted for grain crops should be preferentially guaranteed to ensure food security, in spite of higher economic compensation in other cash crops' irrigation for water coordination. Updating water-saving engineering and adopting drip irrigation technology in agricultural facilities after satisfying environmental flows would greatly relieve agricultural water shortage and save the economic compensation for different irrigation stakeholders. The approach in this study can be easily applied in water-stressed areas worldwide for dealing with water competition.

Reproductive effort and the egg number vs. size trade-off in Physalaemus frogs (Anura: Leiuperidae)

Science.gov (United States)

Camargo, Arley; Sarroca, Macarena; Maneyro, Raúl

2008-09-01

Patterns of reproductive allocation are expected to differ between species according to temporally and spatially variable costs of reproduction. Even when reproductive allocation patterns are the same, species can also differ in how the reproductive effort is allocated between offspring number and size. In this study, we compared the reproductive allocation patterns and the offspring number vs. size trade-off in two frog species, Physalaemus biligonigerus and P. gracilis, using bivariate (standardized major axis) and multiple linear regressions. Both species showed a common slope between body size and reproductive effort and thus a similar allocation pattern although P. biligonigerus has a larger body size (shift along common slope) and makes a lower reproductive effort (shift in intercept) than P. gracilis. We suggest that similar allocation patterns may be related to the shared phenologies of these frogs and that the differences in reproductive effort could represent either an adaptive shift (e.g., change in body space for the clutch) or a historical constraint. There was a negative correlation between fecundity and egg size in P. biligonigerus but not in P. gracilis as predicted by the acquisition-allocation model (Y-model). This study constitutes the first valid test of the Y-model based on recent predictions derived for the trade-off between offspring size vs. number. We conclude that future studies should compare reproductive allocation patterns between species using tests of allometric slopes with appropriate phylogenetic control to detect both adaptive shifts in allocation strategies and correlations with other life-history traits.

Evaluating trade-offs in bull trout reintroduction strategies using structured decision making

Science.gov (United States)

Brignon, William R.; Peterson, James T.; Dunham, Jason B.; Schaller, Howard A.; Schreck, Carl B.

2018-01-01

Structured decision making allows reintroduction decisions to be made despite uncertainty by linking reintroduction goals with alternative management actions through predictive models of ecological processes. We developed a decision model to evaluate the trade-offs between six bull trout (Salvelinus confluentus) reintroduction decisions with the goal of maximizing the number of adults in the recipient population without reducing the donor population to an unacceptable level. Sensitivity analyses suggested that the decision identity and outcome were most influenced by survival parameters that result in increased adult abundance in the recipient population, increased juvenile survival in the donor and recipient populations, adult fecundity rates, and sex ratio. The decision was least sensitive to survival parameters associated with the captive-reared population, the effect of naivety on released individuals, and juvenile carrying capacity of the reintroduced population. The model and sensitivity analyses can serve as the foundation for formal adaptive management and improved effectiveness, efficiency, and transparency of bull trout reintroduction decisions.

A trade-off between length and width in resolution

Czech Academy of Sciences Publication Activity Database

Thapen, Neil

2016-01-01

Roč. 12, č. 5 (2016), s. 1-14 ISSN 1557-2862 R&D Projects: GA ČR GBP202/12/G061 Institutional support: RVO:67985840 Keywords : proof complexity * resolution * trade-off Subject RIV: BA - General Mathematics http:// toc .nada.kth.se/ articles /v012a005/index.html

An overview of tradeoff curve analysis in the design of manufacturing systems Uma visão geral da análise de curvas de tradeoff no projeto de sistemas de manufatura

Directory of Open Access Journals (Sweden)

Gabriel R. Bitran

1996-08-01

Full Text Available Uncertainty in manufacturing systems has long been the source of managerial complexity. In this paper we discuss the impact of different sources of uncertainty and present a methodology to assess their impact on system behavior. We introduce the concept of tradeoff curves as a characteristic of a manufacturing system and illustrate their use to make decisions concerning the amount and type of capacity necessary to manage the system efficiently, to assess the impact of products arrival and processing uncertainties, as well as the consequences of changes in throughput and product mix. The methodology is illustrated with an example derived from an actual application in the semiconductor industry.Incerteza nos sistemas de manufatura tem sido há muito tempo fonte de complexidade gerencial. Neste artigo discutimos o impacto de diferentes fontes de incerteza e apresentamos um metodologia para avaliar tal impacto no comportamento do sistema. Introduzimos o conceito de curvas de tradeoff como uma característica de um sistema de manufatura e ilustramos sua utilização para tomar decisões com respeito à quantidade e tipo de capacidade necessária para gerir o sistema eficientemente, para avaliar o impacto de incerteza na chegada e processamento de produtos, assim como as conseqüências de mudanças na taxa média de produção e no mix de produtos. A metodologia é ilustrada com um exemplo derivado de uma aplicação real numa indústria de semicondutores.

Re-examining the risk–return relationship in Europe: Linear or non-linear trade-off?

OpenAIRE

Salvador, Enrique; Floros, Christos; Arago, Vicent

2014-01-01

This paper analyzes the risk–return trade-off in Europe using recent data from 11 European stock markets. After relaxing the linear assumptions in the risk–return relationship by introducing a new approach that considers the current state of the market, we obtain significant evidence for a positive risk–return trade-off for low volatility states. However, this finding is reduced or even non-significant during periods of high volatility. Maintaining the linear assumption over the risk–return t...

Trade-offs between developmental parameters of two endoparasitoids developing in different instars of the same host species

NARCIS (Netherlands)

Malčická, Mima; Harvey, J.A.

2014-01-01

Trade-offs amongst life history traits is a major theme in evolutionary biology. Parasitoid wasps are important biological control agents and make excellent organisms to examine trade-offs in fitness related traits such as size, development rate and survival. Here, we examined trait-related

Beyond optimality: Multistakeholder robustness tradeoffs for regional water portfolio planning under deep uncertainty

Science.gov (United States)

Herman, Jonathan D.; Zeff, Harrison B.; Reed, Patrick M.; Characklis, Gregory W.

2014-10-01

While optimality is a foundational mathematical concept in water resources planning and management, "optimal" solutions may be vulnerable to failure if deeply uncertain future conditions deviate from those assumed during optimization. These vulnerabilities may produce severely asymmetric impacts across a region, making it vital to evaluate the robustness of management strategies as well as their impacts for regional stakeholders. In this study, we contribute a multistakeholder many-objective robust decision making (MORDM) framework that blends many-objective search and uncertainty analysis tools to discover key tradeoffs between water supply alternatives and their robustness to deep uncertainties (e.g., population pressures, climate change, and financial risks). The proposed framework is demonstrated for four interconnected water utilities representing major stakeholders in the "Research Triangle" region of North Carolina, U.S. The utilities supply well over one million customers and have the ability to collectively manage drought via transfer agreements and shared infrastructure. We show that water portfolios for this region that compose optimal tradeoffs (i.e., Pareto-approximate solutions) under expected future conditions may suffer significantly degraded performance with only modest changes in deeply uncertain hydrologic and economic factors. We then use the Patient Rule Induction Method (PRIM) to identify which uncertain factors drive the individual and collective vulnerabilities for the four cooperating utilities. Our framework identifies key stakeholder dependencies and robustness tradeoffs associated with cooperative regional planning, which are critical to understanding the tensions between individual versus regional water supply goals. Cooperative demand management was found to be the key factor controlling the robustness of regional water supply planning, dominating other hydroclimatic and economic uncertainties through the 2025 planning horizon. Results

The fitness costs and trade-off shapes associated with the exclusion of nine antibiotics by OmpF porin channels.

Science.gov (United States)

Phan, Katherine; Ferenci, Thomas

2017-06-01

The trade-off relationship between antibiotic exclusion and nutrient access across the Gram-negative outer membrane is determined by structural constraints in porin channels. The precise nutritional cost of exclusion is unknown for different antibiotics, as are the shapes of the nutrition-susceptibility trade-off. Using a library of 10 engineered isogenic Escherichia coli strains with structural modifications of OmpF porin expressed at a constant level, susceptibilities were measured for nine antibiotics and the nutritional fitness costs estimated by competitions in chemostats. Different antibiotics exhibited a remarkably varied range of geometries in the nutrition-susceptibility trade-off, including convex, concave and sigmoidal trade-off shapes. The trade-off patterns predict the possibility of adaptations in contributing to antibiotic resistance; exclusion of amoxicillin or trimethoprim in ompF mutants can occur with little loss of fitness whereas kanamycin and streptomycin exclusion has a high cost. Some individual OmpF changes even allow positive correlations (trade-ups), resulting in increased fitness and decreased susceptibility specifically to cephalexin or ciprofloxacin. The surprising plasticity of the nutrition-exclusion relationship means that there are no generalisable rules that apply to decreasing susceptibility for all antibiotics. The protein changes are exquisitely specific in determining nutritional fitness and adaptive outcomes in a structural constraint trade-off.

Is there an ideal REDD+ program? An analysis of policy trade-offs at the local level.

Science.gov (United States)

Dyer, George A; Matthews, Robin; Meyfroidt, Patrick

2012-01-01

We use economy-wide simulation methods to analyze the outcome of a simple REDD+ program in a mixed subsistence/commercial-agriculture economy. Alternative scenarios help trace REDD+'s causal chain, revealing how trade-offs between the program's public and private costs and benefits determine its effectiveness, efficiency and equity (the 3Es). Scenarios reveal a complex relationship between the 3Es not evident in more aggregate analyses. Setting aside land as a carbon sink always influences the productivity of agriculture and its supply of non-market goods and services; but the overall returns to land and labor-which ultimately determine the opportunity cost of enrollment, the price of carbon and the distribution of gains and losses-depend on local conditions. In the study area, market-oriented landowners could enroll 30% of local land into a cost-effective program, but local subsistence demands would raise their opportunity costs as REDD+ unfurls, increasing the marginal cost of carbon. A combination of rent and wage changes would create net costs for most private stakeholders, including program participants. Increasing carbon prices undermines the program's efficiency without solving its inequities; expanding the program reduces inefficiencies but increases private costs with only minor improvements in equity. A program that prevents job losses could be the best option, but its efficiency compared to direct compensation could depend on program scale. Overall, neither the cost nor the 3Es of alternative REDD+ programs can be assessed without accounting for local demand for subsistence goods and services. In the context of Mexico's tropical highlands, a moderate-sized REDD+ program could at best have no net impact on rural households. REDD+ mechanisms should avoid general formulas by giving local authorities the necessary flexibility to address the trade-offs involved. National programs themselves should remain flexible enough to adjust for spatially and temporally

Is there an ideal REDD+ program? An analysis of policy trade-offs at the local level.

Directory of Open Access Journals (Sweden)

George A Dyer

Full Text Available We use economy-wide simulation methods to analyze the outcome of a simple REDD+ program in a mixed subsistence/commercial-agriculture economy. Alternative scenarios help trace REDD+'s causal chain, revealing how trade-offs between the program's public and private costs and benefits determine its effectiveness, efficiency and equity (the 3Es. Scenarios reveal a complex relationship between the 3Es not evident in more aggregate analyses. Setting aside land as a carbon sink always influences the productivity of agriculture and its supply of non-market goods and services; but the overall returns to land and labor-which ultimately determine the opportunity cost of enrollment, the price of carbon and the distribution of gains and losses-depend on local conditions. In the study area, market-oriented landowners could enroll 30% of local land into a cost-effective program, but local subsistence demands would raise their opportunity costs as REDD+ unfurls, increasing the marginal cost of carbon. A combination of rent and wage changes would create net costs for most private stakeholders, including program participants. Increasing carbon prices undermines the program's efficiency without solving its inequities; expanding the program reduces inefficiencies but increases private costs with only minor improvements in equity. A program that prevents job losses could be the best option, but its efficiency compared to direct compensation could depend on program scale. Overall, neither the cost nor the 3Es of alternative REDD+ programs can be assessed without accounting for local demand for subsistence goods and services. In the context of Mexico's tropical highlands, a moderate-sized REDD+ program could at best have no net impact on rural households. REDD+ mechanisms should avoid general formulas by giving local authorities the necessary flexibility to address the trade-offs involved. National programs themselves should remain flexible enough to adjust for

Valuing trade-offs of river ecosystem services in large hydropower development in Tibet, China

Science.gov (United States)

Yu, B.; Xu, L.

2015-12-01

Hydropower development can be considered as a kind of trade-offs of ecosystem services generated by human activity for their economic and energy demand, because it can increase some river ecosystem services but decrease others. In this context, an ecosystem service trade-off framework in hydropower development was proposed in this paper. It aims to identify the ecological cost of river ecosystem and serve for the ecological compensation during hydropower development, for the hydropower services cannot completely replace the regulating services of river ecosystem. The valuing trade-offs framework was integrated by the influenced ecosystem services identification and ecosystem services valuation, through ecological monitoring and ecological economic methods, respectively. With a case study of Pondo hydropower project in Tibet, China, the valuing trade-offs of river ecosystem services in large hydropower development was illustrated. The typical ecological factors including water, sediment and soil were analyzed in this study to identify the altered river ecosystem services by Pondo hydropower project. Through the field monitoring and valuation, the results showed that the Lhasa River ecosystem services value could be changed annually by Pondo hydropower project with the increment of 5.7E+8CNY, and decrement of 5.1E+7CNY. The ecological compensation for river ecosystem should be focus on water and soil conservation, reservoir dredging and tributaries habitat protection.

Has the tradeoff between productivity gains and job growth disappeared?

NARCIS (Netherlands)

P.A.D. Cavelaars

2004-01-01

textabstractPolicymakers’ efforts to boost trend output growth may be hampered by the presence of a tradeoff between productivity gains and job creation. This paper presents empirical evidence that the negative relationship between productivity growth and employment growth that prevailed in the

The role of trade-offs in biodiversity conservation planning: linking ...

Indian Academy of Sciences (India)

A recent whole-country planning study for Papua New Guinea illustrates the importance of complementarity-based trade-offs in determining priority areas for biodiversity conservation, and for designing economic instruments such as biodiversity levies and offsets. Two international biodiversity programs provide important ...

Discount rates in risk versus money and money versus money tradeoffs.

Science.gov (United States)

Alberini, Anna; Chiabai, Aline

2007-04-01

We use data from a survey of residents of five Italian cities conducted in late spring 2004 to estimate the discount rates implicit in (1) money versus future risk reductions and (2) money versus money tradeoffs. We find that the mean personal discount rate is 0.3-1.7% in (1) and 8.7% in (2). The latter is lower than the discount rates estimated in comparable situations in many recent studies, greater than market interest rates in Italy at the time, and exhibits modest variation with age and gender. The discount rate implicit in money versus risk tradeoffs is within the range of estimates from studies in the United States and Europe, and does not depend on observable individual characteristics. We use split samples to investigate whether a completely abstract risk reduction - one where the risk reduction delivery has been stripped of all specifics, so that respondents should focus on the risks without being distracted by details - results in WTP and discount figures comparable to those from an identified delivery mechanism (a medical test). We find that while WTP for an immediate risk reduction is 42-73% higher with the abstract risk reduction, the discount rate in the money versus risk tradeoffs and the variance of the error term in the WTP equation are the same across the two variants of the questionnaire.

Transient dynamics in trial-offer markets with social influence: Trade-offs between appeal and quality.

Science.gov (United States)

Altszyler, Edgar; Berbeglia, Franco; Berbeglia, Gerardo; Van Hentenryck, Pascal

2017-01-01

We study a trial-offer market where consumers may purchase one of two competing products. Consumer preferences are affected by the products quality, their appeal, and their popularity. While the asymptotic convergence or stationary states of these, and related dynamical systems, has been vastly studied, the literature regarding the transitory dynamics remains surprisingly sparse. To fill this gap, we derive a system of Ordinary Differential Equations, which is solved exactly to gain insight into the roles played by product qualities and appeals in the market behavior. We observe a logarithmic tradeoff between quality and appeal for medium and long-term marketing strategies: The expected market shares remain constant if a decrease in quality is followed by an exponential increase in the product appeal. However, for short time horizons, the trade-off is linear. Finally, we study the variability of the dynamics through Monte Carlo simulations and discover that low appeals may result in high levels of variability. The model results suggest effective marketing strategies for short and long time horizons and emphasize the significance of advertising early in the market life to increase sales and predictability.

Transient dynamics in trial-offer markets with social influence: Trade-offs between appeal and quality

Science.gov (United States)

Altszyler, Edgar; Berbeglia, Franco; Van Hentenryck, Pascal

2017-01-01

We study a trial-offer market where consumers may purchase one of two competing products. Consumer preferences are affected by the products quality, their appeal, and their popularity. While the asymptotic convergence or stationary states of these, and related dynamical systems, has been vastly studied, the literature regarding the transitory dynamics remains surprisingly sparse. To fill this gap, we derive a system of Ordinary Differential Equations, which is solved exactly to gain insight into the roles played by product qualities and appeals in the market behavior. We observe a logarithmic tradeoff between quality and appeal for medium and long-term marketing strategies: The expected market shares remain constant if a decrease in quality is followed by an exponential increase in the product appeal. However, for short time horizons, the trade-off is linear. Finally, we study the variability of the dynamics through Monte Carlo simulations and discover that low appeals may result in high levels of variability. The model results suggest effective marketing strategies for short and long time horizons and emphasize the significance of advertising early in the market life to increase sales and predictability. PMID:28746334

Transient dynamics in trial-offer markets with social influence: Trade-offs between appeal and quality.

Directory of Open Access Journals (Sweden)

Edgar Altszyler

Full Text Available We study a trial-offer market where consumers may purchase one of two competing products. Consumer preferences are affected by the products quality, their appeal, and their popularity. While the asymptotic convergence or stationary states of these, and related dynamical systems, has been vastly studied, the literature regarding the transitory dynamics remains surprisingly sparse. To fill this gap, we derive a system of Ordinary Differential Equations, which is solved exactly to gain insight into the roles played by product qualities and appeals in the market behavior. We observe a logarithmic tradeoff between quality and appeal for medium and long-term marketing strategies: The expected market shares remain constant if a decrease in quality is followed by an exponential increase in the product appeal. However, for short time horizons, the trade-off is linear. Finally, we study the variability of the dynamics through Monte Carlo simulations and discover that low appeals may result in high levels of variability. The model results suggest effective marketing strategies for short and long time horizons and emphasize the significance of advertising early in the market life to increase sales and predictability.

Hydrology-oriented forest management trade-offs. A modeling framework coupling field data, simulation results and Bayesian Networks.

Science.gov (United States)

Garcia-Prats, Alberto; González-Sanchis, María; Del Campo, Antonio D; Lull, Cristina

2018-05-23

Hydrology-oriented forest management sets water as key factor of the forest management for adaptation due to water is the most limiting factor in the Mediterranean forest ecosystems. The aim of this study was to apply Bayesian Network modeling to assess potential indirect effects and trade-offs when hydrology-oriented forest management is applied to a real Mediterranean forest ecosystem. Water, carbon and nitrogen cycles, and forest fire risk were included in the modeling framework. Field data from experimental plots were employed to calibrate and validate the mechanistic Biome-BGCMuSo model that simulates the storage and flux of water, carbon, and nitrogen between the ecosystem and the atmosphere. Many other 50-year long scenarios with different conditions to the ones measured in the field experiment were simulated and the outcomes employed to build the Bayesian Network in a linked chain of models. Hydrology-oriented forest management was very positive insofar as more water was made available to the stand because of an interception reduction. This resource was made available to the stand, which increased the evapotranspiration and its components, the soil water content and a slightly increase of deep percolation. Conversely, Stemflow was drastically reduced. No effect was observed on Runof due to the thinning treatment. The soil organic carbon content was also increased which in turn caused a greater respiration. The long-term effect of the thinning treatment on the LAI was very positive. This was undoubtedly due to the increased vigor generated by the greater availability of water and nutrients for the stand and the reduction of competence between trees. This greater activity resulted in an increase in GPP and vegetation carbon, and therefore, we would expect a higher carbon sequestration. It is worth emphasizing that this extra amount of water and nutrients was taken up by the stand and did not entail any loss of nutrients. Copyright © 2018 Elsevier B.V. All

Providing high-quality care in primary care settings: how to make trade-offs.

Science.gov (United States)

Beaulieu, Marie-Dominique; Geneau, Robert; Del Grande, Claudio; Denis, Jean-Louis; Hudon, Eveline; Haggerty, Jeannie L; Bonin, Lucie; Duplain, Réjean; Goudreau, Johanne; Hogg, William

2014-05-01

To gain a deeper understanding of how primary care (PC) practices belonging to different models manage resources to provide high-quality care. Multiple-case study embedded in a cross-sectional study of a random sample of 37 practices. Three regions of Quebec. Health care professionals and staff of 5 PC practices. Five cases showing above-average results on quality-of-care indicators were purposefully selected to contrast on region, practice size, and PC model. Data were collected using an organizational questionnaire; the Team Climate Inventory, which was completed by health care professionals and staff; and 33 individual interviews. Detailed case histories were written and thematic analysis was performed. The core common feature of these practices was their ongoing effort to make trade-offs to deliver services that met their vision of high-quality care. These compromises involved the same 3 areas, but to varying degrees depending on clinic characteristics: developing a shared vision of high-quality care; aligning resource use with that vision; and balancing professional aspirations and population needs. The leadership of the physician lead was crucial. The external environment was perceived as a source of pressure and dilemmas rather than as a source of support in these matters. Irrespective of their models, PC practices' pursuit of high-quality care is based on a vision in which accessibility is a key component, balanced by appropriate management of available resources and of external environment expectations. Current PC reforms often create tensions rather than support PC practices in their pursuit of high-quality care. Copyright© the College of Family Physicians of Canada.

Adaptive transmission schemes for MISO spectrum sharing systems: Tradeoffs and performance analysis

KAUST Repository

Bouida, Zied

2014-10-01

In this paper, we propose a number of adaptive transmission techniques in order to improve the performance of the secondary link in a spectrum sharing system. We first introduce the concept of minimum-selection maximum ratio transmission (MS-MRT) as an adaptive variation of the existing MRT (MRT) technique. While in MRT all available antennas are used for transmission, MS-MRT uses the minimum subset of antennas verifying both the interference constraint (IC) to the primary user and the bit error rate (BER) requirements. Similar to MRT, MS-MRT assumes that perfect channel state information (CSI) is available at the secondary transmitter (ST), which makes this scheme challenging from a practical point of view. To overcome this challenge, we propose another transmission technique based on orthogonal space-time block codes with transmit antenna selection (TAS). This technique uses the full-rate full-diversity Alamouti scheme in order to maximize the secondary\\'s transmission rate. The performance of these techniques is analyzed in terms of the average spectral efficiency (ASE), average number of transmit antennas, average delay, average BER, and outage performance. In order to give the motivation behind these analytical results, the tradeoffs offered by the proposed schemes are summarized and then demonstrated through several numerical examples.

Atomic Layer Etching of Silicon to Solve ARDE-Selectivity-Profile-Uniformity Trade-Offs

Science.gov (United States)

Wang, Mingmei; Ranjan, Alok; Ventzek, Peter; Koshiishi, Akira

2014-10-01

With shrinking critical dimensions, dry etch faces more and more challenges. Minimizing each of aspect ratio dependent etching (ARDE), bowing, undercut, selectivity, and within die uniformly across a wafer are met by trading off one requirement against another. At the root of the problem is that roles radical flux, ion flux and ion energy play may be both good and bad. Increasing one parameter helps meeting one requirement but hinders meeting the other. Self-limiting processes like atomic layer etching (ALE) promise a way to escape the problem of balancing trade-offs. ALE was realized in the mid-1990s but the industrial implementation has been slow. In recent years interest in ALE has revived. We present how ARDE, bowing/selectivity trade-offs may be overcome by varying radical/ion ratio, byproduct re-deposition. We overcome many of the practical implementation issues associated with ALE by precise passivation process control. The Monte Carlo Feature Profile Model (MCFPM) is used to illustrate realistic scenarios built around an Ar/Cl2 chemistry driven etch of Si masked by SiO2. We demonstrate that ALE can achieve zero ARDE and infinite selectivity. Profile control depends on careful management of the ion energies and angles. For ALE to be realized in production environment, tight control of IAD is a necessary. Experimental results are compared with simulation results to provide context to the work.

Examining current or future trade-offs for biodiversity conservation in north-eastern Australia.

Science.gov (United States)

Reside, April E; VanDerWal, Jeremy; Moilanen, Atte; Graham, Erin M

2017-01-01

With the high rate of ecosystem change already occurring and predicted to occur in the coming decades, long-term conservation has to account not only for current biodiversity but also for the biodiversity patterns anticipated for the future. The trade-offs between prioritising future biodiversity at the expense of current priorities must be understood to guide current conservation planning, but have been largely unexplored. To fill this gap, we compared the performance of four conservation planning solutions involving 662 vertebrate species in the Wet Tropics Natural Resource Management Cluster Region in north-eastern Australia. Input species data for the four planning solutions were: 1) current distributions; 2) projected distributions for 2055; 3) projected distributions for 2085; and 4) current, 2055 and 2085 projected distributions, and the connectivity between each of the three time periods for each species. The four planning solutions were remarkably similar (up to 85% overlap), suggesting that modelling for either current or future scenarios is sufficient for conversation planning for this region, with little obvious trade-off. Our analyses also revealed that overall, species with small ranges occurring across steep elevation gradients and at higher elevations were more likely to be better represented in all solutions. Given that species with these characteristics are of high conservation significance, our results provide confidence that conservation planning focused on either current, near- or distant-future biodiversity will account for these species.

Risk-sensitivity and the mean-variance trade-off: decision making in sensorimotor control.

Science.gov (United States)

Nagengast, Arne J; Braun, Daniel A; Wolpert, Daniel M

2011-08-07

Numerous psychophysical studies suggest that the sensorimotor system chooses actions that optimize the average cost associated with a movement. Recently, however, violations of this hypothesis have been reported in line with economic theories of decision-making that not only consider the mean payoff, but are also sensitive to risk, that is the variability of the payoff. Here, we examine the hypothesis that risk-sensitivity in sensorimotor control arises as a mean-variance trade-off in movement costs. We designed a motor task in which participants could choose between a sure motor action that resulted in a fixed amount of effort and a risky motor action that resulted in a variable amount of effort that could be either lower or higher than the fixed effort. By changing the mean effort of the risky action while experimentally fixing its variance, we determined indifference points at which participants chose equiprobably between the sure, fixed amount of effort option and the risky, variable effort option. Depending on whether participants accepted a variable effort with a mean that was higher, lower or equal to the fixed effort, they could be classified as risk-seeking, risk-averse or risk-neutral. Most subjects were risk-sensitive in our task consistent with a mean-variance trade-off in effort, thereby, underlining the importance of risk-sensitivity in computational models of sensorimotor control.

Sibling Competition & Growth Tradeoffs. Biological vs. Statistical Significance

OpenAIRE

Kramer, Karen L.; Veile, Amanda; Ot?rola-Castillo, Erik

2016-01-01

Early childhood growth has many downstream effects on future health and reproduction and is an important measure of offspring quality. While a tradeoff between family size and child growth outcomes is theoretically predicted in high-fertility societies, empirical evidence is mixed. This is often attributed to phenotypic variation in parental condition. However, inconsistent study results may also arise because family size confounds the potentially differential effects that older and younger s...

Dual worth trade-off method and its application for solving multiple criteria decision making problems

Institute of Scientific and Technical Information of China (English)

Feng Junwen

2006-01-01

To overcome the limitations of the traditional surrogate worth trade-off (SWT) method and solve the multiple criteria decision making problem more efficiently and interactively, a new method labeled dual worth trade-off (DWT) method is proposed. The DWT method dynamically uses the duality theory related to the multiple criteria decision making problem and analytic hierarchy process technique to obtain the decision maker's solution preference information and finally find the satisfactory compromise solution of the decision maker. Through the interactive process between the analyst and the decision maker, trade-off information is solicited and treated properly, the representative subset of efficient solutions and the satisfactory solution to the problem are found. The implementation procedure for the DWT method is presented. The effectiveness and applicability of the DWT method are shown by a practical case study in the field of production scheduling.

Trade-offs between carbon, water, soil and food in Guanzhong-Tianshui economic region from remotely sensed data

Science.gov (United States)

Zhou, Z. X.; Li, Jing; Guo, Z. Z.; Li, Ting

2017-06-01

It is important to ensure the efficient supply of land ecosystem services when the competition for land is increasing. In this paper we simulated the ecosystem services function under two scenarios, including carbon sequestration, agricultural production, water and soil conservation, and analyzed the tradeoffs among these ecosystem services in Guanzhong-Tianshui region from 2000 to 2050. Then the productive efficiency of ecosystem services was assessed under two scenarios and compared their production possibility frontiers (PPFs). Through the simulation analysis of their optimum allocation, we also provide the scientific evidence to the development of ecosystem. The natural rules were revealed that if these trade-offs emphasize the potential to sequester carbon in the landscape, along with very little loss of agricultural production, much more water is used. It could be identified to adhere to combine the exploitation and utilization, remediation and protection for land to promote the effective circulation of land eco-system, and meet the society's preferences for land ecosystem service function by adjusting the use of multiple eco-services.

Nuclear propulsion tradeoffs for manned Mars missions

International Nuclear Information System (INIS)

Walton, L.A.; Malloy, J.D.

1991-01-01

A conjunction class split/sprint manned Mars exploration mission was studied to evaluate tradeoffs in performance characteristics of nuclear thermal rockets. A Particle Bed Reactor-based nuclear thermal rocket was found to offer a 38% to 52% total mass savings compared with a NERVA-based nuclear thermal rocket for this mission. This advantage is primarily due to the higher thrust-to-weight ratio of the Particle Bed Reactor nuclear rocket. The mission is enabled by nuclear thermal rockets. It cannot be performed practically using chemical propulsion

Viruses' life history: towards a mechanistic basis of a trade-off between survival and reproduction among phages.

Directory of Open Access Journals (Sweden)

Marianne De Paepe

2006-07-01

Full Text Available Life history theory accounts for variations in many traits involved in the reproduction and survival of living organisms, by determining the constraints leading to trade-offs among these different traits. The main life history traits of phages-viruses that infect bacteria-are the multiplication rate in the host, the survivorship of virions in the external environment, and their mode of transmission. By comparing life history traits of 16 phages infecting the bacteria Escherichia coli, we show that their mortality rate is constant with time and positively [corrected] correlated to their multiplication rate in the bacterial host. Even though these viruses do not age, this result is in line with the trade-off between survival and reproduction previously observed in numerous aging organisms. Furthermore, a multiple regression shows that the combined effects of two physical parameters, namely, the capsid thickness and the density of the packaged genome, account for 82% of the variation in the mortality rate. The correlations between life history traits and physical characteristics of virions may provide a mechanistic explanation of this trade-off. The fact that this trade-off is present in this very simple biological situation suggests that it might be a fundamental property of evolving entities produced under constraints. Moreover, such a positive correlation between mortality and multiplication reveals an underexplored trade-off in host-parasite interactions.

Tradeoffs between image quality and dose

International Nuclear Information System (INIS)

Seibert, J.A.

2004-01-01

Image quality takes on different perspectives and meanings when associated with the concept of as low as reasonably achievable (ALARA), which is chiefly focused on radiation dose delivered as a result of a medical imaging procedure. ALARA is important because of the increased radiosensitivity of children to ionizing radiation and the desire to keep the radiation dose low. By the same token, however, image quality is also important because of the need to provide the necessary information in a radiograph in order to make an accurate diagnosis. Thus, there are tradeoffs to be considered between image quality and radiation dose, which is the main topic of this article. ALARA does not necessarily mean the lowest radiation dose, nor, when implemented, does it result in the least desirable radiographic images. With the recent widespread implementation of digital radiographic detectors and displays, a new level of flexibility and complexity confronts the technologist, physicist, and radiologist in optimizing the pediatric radiography exam. This is due to the separation of the acquisition, display, and archiving events that were previously combined by the screen-film detector, which allows for compensation for under- and overexposures, image processing, and on-line image manipulation. As explained in the article, different concepts must be introduced for a better understanding of the tradeoffs encountered when dealing with digital radiography and ALARA. In addition, there are many instances during the image acquisition/display/interpretation process in which image quality and associated dose can be compromised. This requires continuous diligence to quality control and feedback mechanisms to verify that the goals of image quality, dose and ALARA are achieved. (orig.)

Molecular and Neuroendocrine Approaches to Understanding Trade-offs: Food, Sex, Aggression, Stress, and Longevity-An Introduction to the Symposium.

Science.gov (United States)

Schneider, Jill E; Deviche, Pierre

2017-12-01

Life history strategies are composed of multiple fitness components, each of which incurs costs and benefits. Consequently, organisms cannot maximize all fitness components simultaneously. This situation results in a dynamic array of trade-offs in which some fitness traits prevail at the expense of others, often depending on context. The identification of specific constraints and trade-offs has helped elucidate physiological mechanisms that underlie variation in behavioral and physiological life history strategies. There is general recognition that trade-offs are made at the individual and population level, but much remains to be learned concerning the molecular neuroendocrine mechanisms that underlie trade-offs. For example, we still do not know whether the mechanisms that underlie trade-offs at the individual level relate to trade-offs at the population level. To advance our understanding of trade-offs, we organized a group of speakers who study neuroendocrine mechanisms at the interface of traits that are not maximized simultaneously. Speakers were invited to represent research from a wide range of taxa including invertebrates (e.g., worms and insects), fish, nonavian reptiles, birds, and mammals. Three general themes emerged. First, the study of trade-offs requires that we investigate traditional endocrine mechanisms that include hormones, neuropeptides, and their receptors, and in addition, other chemical messengers not traditionally included in endocrinology. The latter group includes growth factors, metabolic intermediates, and molecules of the immune system. Second, the nomenclature and theory of neuroscience that has dominated the study of behavior is being re-evaluated in the face of evidence for the peripheral actions of so-called neuropeptides and neurotransmitters and the behavioral repercussions of these actions. Finally, environmental and ecological contexts continue to be critical in unmasking molecular mechanisms that are hidden when study animals

Cognition-Action Trade-Offs Reflect Organization of Attention in Infancy.

Science.gov (United States)

Berger, Sarah E; Harbourne, Regina T; Horger, Melissa N

2018-01-01

This chapter discusses what cognition-action trade-offs in infancy reveal about the organization and developmental trajectory of attention. We focus on internal attention because this aspect is most relevant to the immediate concerns of infancy, such as fluctuating levels of expertise, balancing multiple taxing skills simultaneously, learning how to control attention under variable conditions, and coordinating distinct psychological domains. Cognition-action trade-offs observed across the life span include perseveration during skill emergence, errors and inefficient strategies during decision making, and the allocation of resources when attention is taxed. An embodied cognitive-load account interprets these behavioral patterns as a result of limited attentional resources allocated across simultaneous, taxing task demands. For populations where motor errors could be costly, like infants and the elderly, attention is typically devoted to motor demands with errors occurring in the cognitive domain. In contrast, healthy young adults tend to preserve their cognitive performance by modifying their actions. © 2018 Elsevier Inc. All rights reserved.

An Assessment of Vulnerability and Trade-offs of Dairy Farmers of India to Climate Variability and Change

Science.gov (United States)

Radhakrishnan, Aparna; Gupta, Jancy; Ravindran, Dileepkumar

2017-04-01

The study aims at assessing the vulnerability and tradeoffs of dairy based livelihoods to Climate Variability and Change (CVC) in the Western Ghats ecosystem, India. For this purpose; data were aggregated to an overall Livelihood Vulnerability Index (LVI) to CVC underlying the principles of IPCC, using 40 indicators under 7 LVI components. Fussel framework was used for the nomenclature of vulnerable situation and trade-off between vulnerability components and milk production was calculated. Data were collected through participatory rural appraisal and personal interviews from 360 randomly selected dairy farmers of nine blocks from three states of Western Ghat region, complemented by thirty years of gridded weather data and livestock data. The LVI score of dairy based livelihoods of six taluks were negative. The data were normalized and then combined into three indices of sensitivity, exposure and adaptive capacity, which were then averaged with weights given using principal component analysis, to obtain the overall vulnerability index. Mann Whitney U test was used to find the significant difference between the taluks in terms of LVI and cumulative square root frequency method was used to categorise the farmers. Even though the taluks are geographically closer, there is significant difference in the LVI values of the regions. Results indicated that the Lanja taluks of Maharashtra is the most vulnerable having an overall LVI value -4.17 with 48% farmers falling in highly vulnerable category. Panel regression analysis reveals that there is significant synergy between average milk production and livestock, social network component and trade-off between natural disasters climate variability component of LVI. Policies for incentivizing the 'climate risk adaptation' costs for small and marginal farmers and livelihood infrastructure for mitigating risks and promoting grass root level innovations are necessary to sustain dairy farming of the region. Thus the research will

DECISION USEFULNESS: TRADE-OFF ANTARA RELIABILITY DAN RELEVANCE

OpenAIRE

AGUS INDRA TENAYA

2007-01-01

The purpose of this article is to search for trade-off solution betweenreliability and relevance. Approach that can be used to have more reliable andrelevant financial statement is decision usefulness. This approach suggests thatfinancial statement must be useful to become a base of investors’ decision making.The change function of financial statement from just a tool of responsibility tobecome a tool of decision making has caused historical cost-based financialstatement could not be used to ...

Clutch frequency affects the offspring size-number trade-off in lizards.

Directory of Open Access Journals (Sweden)

Zheng Wang

2011-01-01

Full Text Available Studies of lizards have shown that offspring size cannot be altered by manipulating clutch size in species with a high clutch frequency. This raises a question of whether clutch frequency has a key role in influencing the offspring size-number trade-off in lizards.To test the hypothesis that females reproducing more frequently are less likely to tradeoff offspring size against offspring number, we applied the follicle ablation technique to female Eremias argus (Lacertidae from Handan (HD and Gonghe (GH, the two populations that differ in clutch frequency. Follicle ablation resulted in enlargement of egg size in GH females, but not in HD females. GH females switched from producing a larger number of smaller eggs in the first clutch to a smaller number of larger eggs in the second clutch; HD females showed a similar pattern of seasonal shifts in egg size, but kept clutch size constant between the first two clutches. Thus, the egg size-number trade-off was evident in GH females, but not in HD females.As HD females (mean  = 3.1 clutches per year reproduce more frequently than do GH females (mean  = 1.6 clutches per year, our data therefore validate the hypothesis tested. Our data also provide an inference that maximization of maternal fitness could be achieved in females by diverting a large enough, rather than a higher-than-usual, fraction of the available energy to individual offspring in a given reproductive episode.

A Risk-Constrained Multi-Stage Decision Making Approach to the Architectural Analysis of Mars Missions

Science.gov (United States)

Kuwata, Yoshiaki; Pavone, Marco; Balaram, J. (Bob)

2012-01-01

This paper presents a novel risk-constrained multi-stage decision making approach to the architectural analysis of planetary rover missions. In particular, focusing on a 2018 Mars rover concept, which was considered as part of a potential Mars Sample Return campaign, we model the entry, descent, and landing (EDL) phase and the rover traverse phase as four sequential decision-making stages. The problem is to find a sequence of divert and driving maneuvers so that the rover drive is minimized and the probability of a mission failure (e.g., due to a failed landing) is below a user specified bound. By solving this problem for several different values of the model parameters (e.g., divert authority), this approach enables rigorous, accurate and systematic trade-offs for the EDL system vs. the mobility system, and, more in general, cross-domain trade-offs for the different phases of a space mission. The overall optimization problem can be seen as a chance-constrained dynamic programming problem, with the additional complexity that 1) in some stages the disturbances do not have any probabilistic characterization, and 2) the state space is extremely large (i.e, hundreds of millions of states for trade-offs with high-resolution Martian maps). To this purpose, we solve the problem by performing an unconventional combination of average and minimax cost analysis and by leveraging high efficient computation tools from the image processing community. Preliminary trade-off results are presented.

Influence of Averaging Preprocessing on Image Analysis with a Markov Random Field Model

Science.gov (United States)

Sakamoto, Hirotaka; Nakanishi-Ohno, Yoshinori; Okada, Masato

2018-02-01

This paper describes our investigations into the influence of averaging preprocessing on the performance of image analysis. Averaging preprocessing involves a trade-off: image averaging is often undertaken to reduce noise while the number of image data available for image analysis is decreased. We formulated a process of generating image data by using a Markov random field (MRF) model to achieve image analysis tasks such as image restoration and hyper-parameter estimation by a Bayesian approach. According to the notions of Bayesian inference, posterior distributions were analyzed to evaluate the influence of averaging. There are three main results. First, we found that the performance of image restoration with a predetermined value for hyper-parameters is invariant regardless of whether averaging is conducted. We then found that the performance of hyper-parameter estimation deteriorates due to averaging. Our analysis of the negative logarithm of the posterior probability, which is called the free energy based on an analogy with statistical mechanics, indicated that the confidence of hyper-parameter estimation remains higher without averaging. Finally, we found that when the hyper-parameters are estimated from the data, the performance of image restoration worsens as averaging is undertaken. We conclude that averaging adversely influences the performance of image analysis through hyper-parameter estimation.

Open Source, Social Activism and "Necessary Trade-offs" in the Digital Enclosure: A Case Study of Platform Co-operative, Loomio.org

Directory of Open Access Journals (Sweden)

Sam K Jackson

2016-10-01

Full Text Available This article explores the tensions and tradeoffs facing the open source platform co-operative Loomio.org, an online tool that aims to decentralize power through deliberative decision-making. Combining discourse analysis with political economy, we demonstrate how Loomio’s politics of resistance is built directly into the architectural design and platform structure, which invites users to participate in its development and evolution. Yet by prioritizing its social justice mission, Loomio must make certain tradeoffs around data storage and management that paradoxically threatens to compromise its wider social goals. The realities of operating an open source platform are discussed in the context of the contemporary digital economy. We argue that if platform co-operatives like Loomio are to fully realize their goals, a digital commons unencumbered by capitalism requires access to reliable, affordable and accessible alternatives to the existing Internet infrastructure.

A survival-reproduction trade-off in entomopathogenic nematodes mediated by their bacterial symbionts.

Science.gov (United States)

Emelianoff, Vanya; Chapuis, Elodie; Le Brun, Nathalie; Chiral, Magali; Moulia, Catherine; Ferdy, Jean-Baptiste

2008-04-01

In this work, we investigate the investment of entomopathogenic Steinernema nematodes (Rhabditidae) in their symbiotic association with Xenorhabdus bacteria (Enterobacteriaceae). Their life cycle comprises two phases: (1) a free stage in the soil, where infective juveniles (IJs) of the nematode carry bacteria in a digestive vesicle and search for insect hosts, and (2) a parasitic stage into the insect where bacterial multiplication, nematode reproduction, and production of new IJs occur. Previous studies clearly showed benefits to the association for the nematode during the parasitic stage, but preliminary data suggest the existence of costs to the association for the nematode in free stage. IJs deprived from their bacteria indeed survive longer than symbiotic ones. Here we show that those bacteria-linked costs and benefits lead to a trade-off between fitness traits of the symbiotic nematodes. Indeed IJs mortality positively correlates with their parasitic success in the insect host for symbiotic IJs and not for aposymbiotic ones. Moreover mortality and parasitic success both positively correlate with the number of bacteria carried per IJ, indicating that the trade-off is induced by symbiosis. Finally, the trade-off intensity depends on parental effects and, more generally, is greater under restrictive environmental conditions.

Host and food searching in a parasitic wasp Venturia canescens: a trade-off between current and future reproduction?

NARCIS (Netherlands)

Desouhant, E.; Driessen, G.J.J.; Amat, I.; Bernstein, C.

2005-01-01

Whether to invest in current or future reproduction is an important trade-off in life history evolution. For insect parasitoids, this trade-off is determined, among other factors, by the decision whether to search for hosts (immediate gain of fitness) or food (delayed fitness gains). Although host

TRADE-OFF BETWEEN CARBON STORAGE AND BIOMASS-BASED ENERGY SOURCES ECOSYSTEM SERVICES, THE CASE STUDY FROM THE PROVINCE OF ROVIGO (ITALY

Directory of Open Access Journals (Sweden)

E. Gissi

2014-04-01

Full Text Available Biomass Based Energy Sources (BBES are an Ecosystem Service (ES which can contribute to achieve EU 2020 targets and to ensure energy security. Their effects on other ESs can be different according to biomass typologies, as energy crops and residuals. In order to plan a Greenhouse Gasses (GHGs efficient supply chain and to maintain ES of carbon storage, as well as other related ESs, effect of feedstock chain on Soil Organic Carbon (SOC should be considered. An ESs approach, based on the cascade model, takes into consideration biological interdependencies and management options to assess trade-offs. This study aims to describe and map trade-off between BBES and carbon storage services in Province of Rovigo (Veneto Region, Italy, a mainly intensive cultivated area. Results show that the trade-offs  between the two ESs is potentially high in large part of the territory (75%, while just 25% expresses low possibility of conflict. Possible management options are discussed in order to minimize trade-off between energy provision and climate change mitigation. This study highlights that ESs approach can provide a suitable tool for decision makers, with respect to biomass feedstock chain, whose effects on ecosystems are often underestimated.

Competition-colonization trade-offs, competitive uncertainty, and the evolutionary assembly of species.

Directory of Open Access Journals (Sweden)

Pradeep Pillai

Full Text Available We utilize a standard competition-colonization metapopulation model in order to study the evolutionary assembly of species. Based on earlier work showing how models assuming strict competitive hierarchies will likely lead to runaway evolution and self-extinction for all species, we adopt a continuous competition function that allows for levels of uncertainty in the outcome of competition. We then, by extending the standard patch-dynamic metapopulation model in order to include evolutionary dynamics, allow for the coevolution of species into stable communities composed of species with distinct limiting similarities. Runaway evolution towards stochastic extinction then becomes a limiting case controlled by the level of competitive uncertainty. We demonstrate how intermediate competitive uncertainty maximizes the equilibrium species richness as well as maximizes the adaptive radiation and self-assembly of species under adaptive dynamics with mutations of non-negligible size. By reconciling competition-colonization tradeoff theory with co-evolutionary dynamics, our results reveal the importance of intermediate levels of competitive uncertainty for the evolutionary assembly of species.

Methodology for balancing design and process tradeoffs for deep-subwavelength technologies

Science.gov (United States)

Graur, Ioana; Wagner, Tina; Ryan, Deborah; Chidambarrao, Dureseti; Kumaraswamy, Anand; Bickford, Jeanne; Styduhar, Mark; Wang, Lee

2011-04-01

For process development of deep-subwavelength technologies, it has become accepted practice to use model-based simulation to predict systematic and parametric failures. Increasingly, these techniques are being used by designers to ensure layout manufacturability, as an alternative to, or complement to, restrictive design rules. The benefit of model-based simulation tools in the design environment is that manufacturability problems are addressed in a design-aware way by making appropriate trade-offs, e.g., between overall chip density and manufacturing cost and yield. The paper shows how library elements and the full ASIC design flow benefit from eliminating hot spots and improving design robustness early in the design cycle. It demonstrates a path to yield optimization and first time right designs implemented in leading edge technologies. The approach described herein identifies those areas in the design that could benefit from being fixed early, leading to design updates and avoiding later design churn by careful selection of design sensitivities. This paper shows how to achieve this goal by using simulation tools incorporating various models from sparse to rigorously physical, pattern detection and pattern matching, checking and validating failure thresholds.

Pollinators, pests, and predators: Recognizing ecological trade-offs in agroecosystems.

Science.gov (United States)

Saunders, Manu E; Peisley, Rebecca K; Rader, Romina; Luck, Gary W

2016-02-01

Ecological interactions between crops and wild animals frequently result in increases or declines in crop yield. Yet, positive and negative interactions have mostly been treated independently, owing partly to disciplinary silos in ecological and agricultural sciences. We advocate a new integrated research paradigm that explicitly recognizes cost-benefit trade-offs among animal activities and acknowledges that these activities occur within social-ecological contexts. Support for this paradigm is presented in an evidence-based conceptual model structured around five evidence statements highlighting emerging trends applicable to sustainable agriculture. The full range of benefits and costs associated with animal activities in agroecosystems cannot be quantified by focusing on single species groups, crops, or systems. Management of productive agroecosystems should sustain cycles of ecological interactions between crops and wild animals, not isolate these cycles from the system. Advancing this paradigm will therefore require integrated studies that determine net returns of animal activity in agroecosystems.

Ejaculate economics: testing the effects of male sexual history on the trade-off between sperm and immune function in Australian crickets.

Directory of Open Access Journals (Sweden)

Damian K Dowling

Full Text Available Trade-offs between investment into male sexual traits and immune function provide the foundation for some of the most prominent models of sexual selection. Post-copulatory sexual selection on the male ejaculate is intense, and therefore trade-offs should occur between investment into the ejaculate and the immune system. Examples of such trade-offs exist, including that between sperm quality and immunity in the Australian cricket, Teleogryllus oceanicus. Here, we explore the dynamics of this trade-off, examining the effects that increased levels of sexual interaction have on the viability of a male's sperm across time, and the concomitant effects on immune function. Males were assigned to a treatment, whereby they cohabited with females that were sexually immature, sexually mature but incapable of copulation, or sexually mature and capable of copulation. Sperm viability of each male was then assessed at two time points: six and 13 days into the treatment, and immune function at day 13. Sperm viability decreased across the time points, but only for males exposed to treatment classes involving sexually mature females. This decrease was similar in magnitude across both sexually mature classes, indicating that costs to the expression of high sperm viability are incurred largely through levels of pre-copulatory investment. Males exposed to immature females produced sperm of low viability at both time points. Although we confirmed a weak negative association between sperm viability and lytic activity (a measure of immune response to bacterial infection at day 13, this relationship was not altered across the mating treatment. Our results highlight that sperm viability is a labile trait, costly to produce, and subject to strategic allocation in these crickets.

Coexistence and community structure in a consumer resource model with implicit stoichiometry.

Science.gov (United States)

Orlando, Paul A; Brown, Joel S; Wise, David H

2012-09-01

We combine stoichiometry theory and optimal foraging theory into the MacArthur consumer-resource model. This generates predictions for diet choice, coexistence, and community structure of heterotroph communities. Tradeoffs in consumer resource-garnering traits influence community outcomes. With scarce resources, consumers forage opportunistically for complementary resources and may coexist via tradeoffs in resource encounter rates. In contrast to single currency models, stoichiometry permits multiple equilibria. These alternative stable states occur when tradeoffs in resource encounter rates are stronger than tradeoffs in elemental conversion efficiencies. With abundant resources consumers exhibit partially selective diets for essential resources and may coexist via tradeoffs in elemental conversion efficiencies. These results differ from single currency models, where adaptive diet selection is either opportunistic or selective. Interestingly, communities composed of efficient consumers share many of the same properties as communities based on substitutable resources. However, communities composed of relatively inefficient consumers behave similarly to plant communities as characterized by Tilman's consumer resource theory. The results of our model indicate that the effects of stoichiometry theory on community ecology are dependent upon both consumer foraging behavior and the nature of resource garnering tradeoffs. Copyright © 2012 Elsevier Inc. All rights reserved.

A trade-off between reproduction and feather growth in the barn swallow (Hirundo rustica.

Directory of Open Access Journals (Sweden)

Nicola Saino

Full Text Available Physiological trade-offs mediated by limiting energy, resources or time constrain the simultaneous expression of major functions and can lead to the evolution of temporal separation between demanding activities. In birds, plumage renewal is a demanding activity, which accomplishes fundamental functions, such as allowing thermal insulation, aerodynamics and socio-sexual signaling. Feather renewal is a very expensive and disabling process, and molt is often partitioned from breeding and migration. However, trade-offs between feather renewal and breeding have been only sparsely studied. In barn swallows (Hirundo rustica breeding in Italy and undergoing molt during wintering in sub-Saharan Africa, we studied this trade-off by removing a tail feather from a large sample of individuals and analyzing growth bar width, reflecting feather growth rate, and length of the growing replacement feather in relation to the stage in the breeding cycle at removal and clutch size. Growth bar width of females and length of the growing replacement feather of both sexes were smaller when the original feather had been removed after clutch initiation. Importantly, in females both growth bar width and replacement feather length were negatively predicted by clutch size, and more strongly so for large clutches and when feather removal occurred immediately after clutch completion. Hence, we found strong, coherent evidence for a trade-off between reproduction, and laying effort in particular, and the ability to generate new feathers. These results support the hypothesis that the derived condition of molting during wintering in long-distance migrants is maintained by the costs of overlapping breeding and molt.

Incorporating socio-environmental considerations into project assessment models using multi-criteria analysis: A case study of Sri Lankan hydropower projects

International Nuclear Information System (INIS)

Morimoto, Risako

2013-01-01

Before commissioning any energy projects, conducting robust assessments of different options in terms of their economic and socio-environmental impacts is important for successful project implementation. Yet, there is currently a lack of tools that simultaneously assess sustainability impacts; instead, they are often investigated separately, which gives decision makers somehow disintegrated information. Thus the main objective of this study is to examine how to incorporate socio-environmental considerations into project assessment models. The multi-criteria analysis is applied to the case study of Sri Lankan hydropower projects as an illustrative example. The estimated quantitative relationship between economic, environmental and social impacts of hydropower development is presented in this study. Such estimation, using sustainability indicators of hydropower projects, enables us to understand marginal trade-offs among economic, environmental and social objectives of hydropower development. Hence, this would provide an overview of potential impacts of different scenarios that are designed to be implemented and indicate an optimum mix of hydropower generation. - Highlights: • This study provides an effective hydropower project evaluation method using the MCA. • The proposed tool shows the quantitative relationship explicitly. • Marginal trade-offs between sustainability objectives are presented

Trade-offs in managing commercial consumer returns for online apparel retail

NARCIS (Netherlands)

de Leeuw, S.L.J.M.; Minguela-Rata, B.; Sabet, E.; Boter, J.; Sigurðardóttir, R.

2016-01-01

Purpose – The purpose of this paper is to investigate how online apparel retailers make trade-offs in achieving efficiency in handling consumer returns, attempting to reduce the number of consumer returns they are faced with and increasing sales through returns management.

Trade-off bounds for the Pareto surface approximation in multi-criteria IMRT planning

International Nuclear Information System (INIS)

Serna, J I; Monz, M; Kuefer, K H; Thieke, C

2009-01-01

One approach to multi-criteria IMRT planning is to automatically calculate a data set of Pareto-optimal plans for a given planning problem in a first phase, and then interactively explore the solution space and decide on the clinically best treatment plan in a second phase. The challenge of computing the plan data set is to ensure that all clinically meaningful plans are covered and that as many clinically irrelevant plans as possible are excluded to keep computation times within reasonable limits. In this work, we focus on the approximation of the clinically relevant part of the Pareto surface, the process that constitutes the first phase. It is possible that two plans on the Pareto surface have a small, clinically insignificant difference in one criterion and a significant difference in another criterion. For such cases, only the plan that is clinically clearly superior should be included into the data set. To achieve this during the Pareto surface approximation, we propose to introduce bounds that restrict the relative quality between plans, the so-called trade-off bounds. We show how to integrate these trade-off bounds into the approximation scheme and study their effects. The proposed scheme is applied to two artificial cases and one clinical case of a paraspinal tumor. For all cases, the quality of the Pareto surface approximation is measured with respect to the number of computed plans, and the range of values occurring in the approximation for different criteria is compared. Through enforcing trade-off bounds, the scheme disregards clinically irrelevant plans during the approximation. Thereby, the number of plans necessary to achieve a good approximation quality can be significantly reduced. Thus, trade-off bounds are an effective tool to focus the planning and to reduce computation time.

Trade-off bounds for the Pareto surface approximation in multi-criteria IMRT planning.

Science.gov (United States)

Serna, J I; Monz, M; Küfer, K H; Thieke, C

2009-10-21

One approach to multi-criteria IMRT planning is to automatically calculate a data set of Pareto-optimal plans for a given planning problem in a first phase, and then interactively explore the solution space and decide on the clinically best treatment plan in a second phase. The challenge of computing the plan data set is to ensure that all clinically meaningful plans are covered and that as many clinically irrelevant plans as possible are excluded to keep computation times within reasonable limits. In this work, we focus on the approximation of the clinically relevant part of the Pareto surface, the process that constitutes the first phase. It is possible that two plans on the Pareto surface have a small, clinically insignificant difference in one criterion and a significant difference in another criterion. For such cases, only the plan that is clinically clearly superior should be included into the data set. To achieve this during the Pareto surface approximation, we propose to introduce bounds that restrict the relative quality between plans, the so-called trade-off bounds. We show how to integrate these trade-off bounds into the approximation scheme and study their effects. The proposed scheme is applied to two artificial cases and one clinical case of a paraspinal tumor. For all cases, the quality of the Pareto surface approximation is measured with respect to the number of computed plans, and the range of values occurring in the approximation for different criteria is compared. Through enforcing trade-off bounds, the scheme disregards clinically irrelevant plans during the approximation. Thereby, the number of plans necessary to achieve a good approximation quality can be significantly reduced. Thus, trade-off bounds are an effective tool to focus the planning and to reduce computation time.

Rate-cost tradeoffs in control

KAUST Repository

Kostina, Victoria

2017-02-13

Consider a distributed control problem with a communication channel connecting the observer of a linear stochastic system to the controller. The goal of the controller is minimize a quadratic cost function. The most basic special case of that cost function is the mean-square deviation of the system state from the desired state. We study the fundamental tradeoff between the communication rate r bits/sec and the limsup of the expected cost b, and show a lower bound on the rate necessary to attain b. The bound applies as long as the system noise has a probability density function. If target cost b is not too large, that bound can be closely approached by a simple lattice quantization scheme that only quantizes the innovation, that is, the difference between the controller\\'s belief about the current state and the true state.

On the Trade-off between Energy Consumption and Food Quality Loss in Supermarket Refrigeration Systems

DEFF Research Database (Denmark)

Cai, Junping; Jensen, Jørgen Bauck; Skogestad, Sigurd

2008-01-01

This paper studies the trade-off between energy consumption and food quality loss, at varying ambient conditions, in supermarket refrigeration systems. Compared with the traditional operation with pressure control, a large potential for energy savings without extra loss of food quality is demonst......This paper studies the trade-off between energy consumption and food quality loss, at varying ambient conditions, in supermarket refrigeration systems. Compared with the traditional operation with pressure control, a large potential for energy savings without extra loss of food quality...

The role of trade-offs in biodiversity conservation planning: linking ...

Indian Academy of Sciences (India)

Unknown

[Faith D P and Walker P A 2002 The role of trade-offs in biodiversity conservation planning: linking local management, regional planning and global conservation efforts; J. Biosci. 27 (Suppl. 2) 393–407]. 1. Introduction. A reality of biodiversity conservation planning is that it requires taking into account many things other than ...

DSM vs. NSM: CPU Performance Tradeoffs in Block-Oriented Query Processing

NARCIS (Netherlands)

M. Zukowski (Marcin); N.J. Nes (Niels); P.A. Boncz (Peter)

2008-01-01

textabstractComparisons between the merits of row-wise storage (NSM) and columnar storage (DSM) are typically made with respect to the persistent storage layer of database systems. In this paper, however, we focus on the CPU efficiency tradeoffs of tuple representations inside the query

Time-Space Trade-Offs for the Longest Common Substring Problem

DEFF Research Database (Denmark)

Starikovskaya, Tatiana; Vildhøj, Hjalte Wedel

2013-01-01

The Longest Common Substring problem is to compute the longest substring which occurs in at least d ≥ 2 of m strings of total length n. In this paper we ask the question whether this problem allows a deterministic time-space trade-off using O(n1+ε) time and O(n1-ε) space for 0 ≤ ε ≤ 1. We give a ...... a positive answer in the case of two strings (d = m = 2) and 0 can be solved in O(n1-ε) space and O(n1+ε log2n (d log2n + d2)) time for any 0 ≤ ε ...The Longest Common Substring problem is to compute the longest substring which occurs in at least d ≥ 2 of m strings of total length n. In this paper we ask the question whether this problem allows a deterministic time-space trade-off using O(n1+ε) time and O(n1-ε) space for 0 ≤ ε ≤ 1. We give...

Strategic tradeoffs in competitor dynamics on adaptive networks.

Science.gov (United States)

Hébert-Dufresne, Laurent; Allard, Antoine; Noël, Pierre-André; Young, Jean-Gabriel; Libby, Eric

2017-08-08

Recent empirical work highlights the heterogeneity of social competitions such as political campaigns: proponents of some ideologies seek debate and conversation, others create echo chambers. While symmetric and static network structure is typically used as a substrate to study such competitor dynamics, network structure can instead be interpreted as a signature of the competitor strategies, yielding competition dynamics on adaptive networks. Here we demonstrate that tradeoffs between aggressiveness and defensiveness (i.e., targeting adversaries vs. targeting like-minded individuals) creates paradoxical behaviour such as non-transitive dynamics. And while there is an optimal strategy in a two competitor system, three competitor systems have no such solution; the introduction of extreme strategies can easily affect the outcome of a competition, even if the extreme strategies have no chance of winning. Not only are these results reminiscent of classic paradoxical results from evolutionary game theory, but the structure of social networks created by our model can be mapped to particular forms of payoff matrices. Consequently, social structure can act as a measurable metric for social games which in turn allows us to provide a game theoretical perspective on online political debates.

The effects of trauma exposure and posttraumatic stress disorder (PTSD on the emotion-induced memory trade-off

Directory of Open Access Journals (Sweden)

Katherine R. Mickley Steinmetz

2012-06-01

Full Text Available Many studies of memory changes in individuals with PTSD have focused on memory for trauma. However, it is unclear if these mnemonic differences extend beyond trauma memory to memory for other positive and negative information and if they are specific to individuals with PTSD or extend to other individuals who have experienced trauma. The present study examined the influences of trauma exposure and PTSD on an effect that may parallel tunnel memory in PTSD: the emotion-induced memory trade-off, whereby emotional aspects of an experience are remembered at the expense of the nonemotional context. Three groups (25 with current PTSD, 27 who had experienced trauma but did not have current PTSD, and 25 controls who had neither experienced significant trauma nor met criteria for current PTSD were shown complex visual scenes that included an item (positive, negative, or neutral placed on a neutral background. 45 minutes later, participants underwent a recognition memory test for the items and backgrounds separately. An emotion-induced memory trade-off was said to occur when there was a significant difference in item and background memory for emotional scenes, but not for neutral scenes. People with PTSD, like the other groups, were more likely to remember positive and negative items than neutral items. People with PTSD exhibited a memory trade-off, but this trade-off was no larger than for the non-trauma control group. Trauma-exposed people without a current diagnosis of PTSD did not show a trade-off, because they remembered the items within scenes better than their contexts even for neutral scenes. These results suggest that i the effect of emotion on memory for visual scenes is similar in people with PTSD and control participants, and ii people who have experienced trauma, but do not have PTSD, may have a different way of attending to and remembering visual scenes, exhibiting less of a memory trade-off than either control participants or people with

A model for scheduling projects under the condition of inflation and under penalty and reward arrangements

Directory of Open Access Journals (Sweden)

J.K. Jolayemi

2014-01-01

Full Text Available A zero-one mixed integer linear programming model is developed for the scheduling of projects under the condition of inflation and under penalty and reward arrangements. The effects of inflation on time-cost trade-off curves are illustrated and a modified approach to time-cost trade-off analysis presented. Numerical examples are given to illustrate the model and its properties. The examples show that misleading schedules and inaccurate project-cost estimates will be produced if the inflation factor is neglected in an environment of high inflation. They also show that award of penalty or bonus is a catalyst for early completion of a project, just as it can be expected.

RFamide-related Peptide-3 and the Trade-off between Reproductive and Ingestive Behavior.

Science.gov (United States)

Schneider, Jill E; Benton, Noah A; Russo, Kim A; Klingerman, Candice M; Williams, Wilbur P; Simberlund, Jessica; Abdulhay, Amir; Brozek, Jeremy M; Kriegsfeld, Lance J

2017-12-01

Ingestive and sex behaviors are important for individual survival and reproductive success, but when environmental energy availability is limited, individuals of many different species make a trade-off, forfeiting sex for ingestive behavior. For example, food-deprived female Syrian hamsters (Mesocricetus auratus) forego vaginal scent marking and lordosis (sex behaviors) in favor of foraging, hoarding, and eating food (ingestive behavior). Reproductive processes tend to be energetically costly, and individual survival requires homeostasis in metabolic energy. Thus, during energetic challenges, the chances of survival are enhanced by decreasing the energy expended on reproductive processes. The entire hypothalamic-pituitary-gonadal (HPG) system is inhibited by severe energetic challenges, but comparatively little is known about the effects of mild energetic challenges. We hypothesized that (1) a trade-off is made between sex and ingestive behavior even when the level of food restriction is insufficient to inhibit the HPG system; (2) mild energetic challenges force a trade-off between appetitive ingestive and sex behaviors, but not consummatory versions of the same behaviors; and (3) the trade-off is orchestrated by ovarian steroid modulation of RFamide-related peptide 3 (RFRP-3). In other species, RFRP-3, an ortholog of avian gonadotropin-inhibitory hormone, is implicated in control of behavior in response to energetic challenges and stressful stimuli. In support of our three hypotheses, there is a "dose-response" effect of food restriction and re-feeding on the activation of RFRP-3-immunoreactive cells in the dorsomedial hypothalamus and on appetitive behaviors (food hoarding and sexual motivation), but not on consummatory behaviors (food intake and lordosis), with no significant effect on circulating levels of estradiol or progesterone. The effect of food restriction on the activation of RFRP-3 cells is modulated at the time of estrus in gonadally-intact females

Thermotolerant Yeast Strains Adapted by Laboratory Evolution Show Trade-Off at Ancestral Temperatures and Preadaptation to Other Stresses.

Science.gov (United States)

Caspeta, Luis; Nielsen, Jens

2015-07-21

A major challenge for the production of ethanol from biomass-derived feedstocks is to develop yeasts that can sustain growth under the variety of inhibitory conditions present in the production process, e.g., high osmolality, high ethanol titers, and/or elevated temperatures (≥ 40 °C). Using adaptive laboratory evolution, we previously isolated seven Saccharomyces cerevisiae strains with improved growth at 40 °C. Here, we show that genetic adaptations to high temperature caused a growth trade-off at ancestral temperatures, reduced cellular functions, and improved tolerance of other stresses. Thermotolerant yeast strains showed horizontal displacement of their thermal reaction norms to higher temperatures. Hence, their optimal and maximum growth temperatures increased by about 3 °C, whereas they showed a growth trade-off at temperatures below 34 °C. Computational analysis of the physical properties of proteins showed that the lethal temperature for yeast is around 49 °C, as a large fraction of the yeast proteins denature above this temperature. Our analysis also indicated that the number of functions involved in controlling the growth rate decreased in the thermotolerant strains compared with the number in the ancestral strain. The latter is an advantageous attribute for acquiring thermotolerance and correlates with the reduction of yeast functions associated with loss of respiration capacity. This trait caused glycerol overproduction that was associated with the growth trade-off at ancestral temperatures. In combination with altered sterol composition of cellular membranes, glycerol overproduction was also associated with yeast osmotolerance and improved tolerance of high concentrations of glucose and ethanol. Our study shows that thermal adaptation of yeast is suitable for improving yeast resistance to inhibitory conditions found in industrial ethanol production processes. Yeast thermotolerance can significantly reduce the production costs of biomass

Fundamental Tradeoffs among Reliability, Latency and Throughput in Cellular Networks

DEFF Research Database (Denmark)

Soret, Beatriz; Mogensen, Preben; Pedersen, Klaus I.

2014-01-01

We address the fundamental tradeoffs among latency, reliability and throughput in a cellular network. The most important elements influencing the KPIs in a 4G network are identified, and the inter-relationships among them is discussed. We use the effective bandwidth and the effective capacity......, in which latency and reliability will be two of the principal KPIs....

Analysis of geologic terrain models for determination of optimum SAR sensor configuration and optimum information extraction for exploration of global non-renewable resources. Pilot study: Arkansas Remote Sensing Laboratory, part 1, part 2, and part 3

Science.gov (United States)

Kaupp, V. H.; Macdonald, H. C.; Waite, W. P.; Stiles, J. A.; Frost, F. S.; Shanmugam, K. S.; Smith, S. A.; Narayanan, V.; Holtzman, J. C. (Principal Investigator)

1982-01-01

Computer-generated radar simulations and mathematical geologic terrain models were used to establish the optimum radar sensor operating parameters for geologic research. An initial set of mathematical geologic terrain models was created for three basic landforms and families of simulated radar images were prepared from these models for numerous interacting sensor, platform, and terrain variables. The tradeoffs between the various sensor parameters and the quantity and quality of the extractable geologic data were investigated as well as the development of automated techniques of digital SAR image analysis. Initial work on a texture analysis of SEASAT SAR imagery is reported. Computer-generated radar simulations are shown for combinations of two geologic models and three SAR angles of incidence.

Effect of primary user traffic on sensing-throughput tradeoff for cognitive radios

KAUST Repository

Tang, Liang; Chen, Yunfei; Hines, Evor L.; Alouini, Mohamed-Slim

2011-01-01

The effect of the primary user traffic on the performance of the secondary network is investigated for the tradeoff between the sensing quality and the achievable throughput. Numerical results show that the actual secondary network performance when

Evaluation of Bias-Variance Trade-Off for Commonly Used Post-Summarizing Normalization Procedures in Large-Scale Gene Expression Studies

Science.gov (United States)

Qiu, Xing; Hu, Rui; Wu, Zhixin

2014-01-01

Normalization procedures are widely used in high-throughput genomic data analyses to remove various technological noise and variations. They are known to have profound impact to the subsequent gene differential expression analysis. Although there has been some research in evaluating different normalization procedures, few attempts have been made to systematically evaluate the gene detection performances of normalization procedures from the bias-variance trade-off point of view, especially with strong gene differentiation effects and large sample size. In this paper, we conduct a thorough study to evaluate the effects of normalization procedures combined with several commonly used statistical tests and MTPs under different configurations of effect size and sample size. We conduct theoretical evaluation based on a random effect model, as well as simulation and biological data analyses to verify the results. Based on our findings, we provide some practical guidance for selecting a suitable normalization procedure under different scenarios. PMID:24941114

Networks that optimize a trade-off between efficiency and dynamical resilience

International Nuclear Information System (INIS)

Brede, Markus; Vries, Bert J.M. de

2009-01-01

In this Letter we study networks that have been optimized to realize a trade-off between communication efficiency and dynamical resilience. While the first is related to the average shortest pathlength, we argue that the second can be measured by the largest eigenvalue of the adjacency matrix of the network. Best efficiency is realized in star-like configurations, while enhanced resilience is related to the avoidance of short loops and degree homogeneity. Thus crucially, very efficient networks are not resilient while very resilient networks lack in efficiency. Networks that realize a trade-off between both limiting cases exhibit core-periphery structures, where the average degree of core nodes decreases but core size increases as the weight is gradually shifted from a strong requirement for efficiency and limited resilience towards a smaller requirement for efficiency and a strong demand for resilience. We argue that both, efficiency and resilience are important requirements for network design and highlight how networks can be constructed that allow for both.

The impact of financial crises on the risk-return tradeoff and the leverage effect

DEFF Research Database (Denmark)

Christensen, Bent Jesper; Nielsen, Morten Ørregaard; Zhu, Jie

50% in magnitude during …financial crises. No such changes are observed during NBER recessions, so in this sense …financial crises are special. Applications to a number of major developed and emerging international stock markets confirm the increase in the leverage effect, whereas the international......We investigate the impact of financial crises on two fundamental features of stock returns, namely, the risk-return tradeoff and the leverage effect. We apply the fractionally integrated exponential GARCH-in-mean (FIEGARCH-M) model for daily stock return data, which includes both features...... and allows the co-existence of long memory in volatility and short memory in returns. We extend this model to allow the financial parameters governing the volatility-in-mean effect and the leverage effect to change during financial crises. An application to the daily U.S. stock index return series from 1926...

The impact of financial crises on the risk-return tradeoff and the leverage effect

DEFF Research Database (Denmark)

Christensen, Bent Jesper; Nielsen, Morten Ørregaard; Zhu, Jie

2015-01-01

% in magnitude during financial crises. No such changes are observed during NBER recessions, so in this sense financial crises are special. Applications to a number of major developed and emerging international stock markets confirm the increase in the leverage effect, whereas the international evidence......We investigate the impact of financial crises on two fundamental features of stock returns, namely, the risk-return tradeoff and the leverage effect. We apply the fractionally integrated exponential GARCH-in-mean (FIEGARCH-M) model for daily stock return data, which includes both features...... and allows the co-existence of long memory in volatility and short memory in returns. We extend this model to allow the financial parameters governing the volatility-in-mean effect and the leverage effect to change during financial crises. An application to the daily U.S. stock index return series from 1926...

Integrated modeling approach for optimal management of water, energy and food security nexus

Science.gov (United States)

Zhang, Xiaodong; Vesselinov, Velimir V.

2017-03-01

Water, energy and food (WEF) are inextricably interrelated. Effective planning and management of limited WEF resources to meet current and future socioeconomic demands for sustainable development is challenging. WEF production/delivery may also produce environmental impacts; as a result, green-house-gas emission control will impact WEF nexus management as well. Nexus management for WEF security necessitates integrated tools for predictive analysis that are capable of identifying the tradeoffs among various sectors, generating cost-effective planning and management strategies and policies. To address these needs, we have developed an integrated model analysis framework and tool called WEFO. WEFO provides a multi-period socioeconomic model for predicting how to satisfy WEF demands based on model inputs representing productions costs, socioeconomic demands, and environmental controls. WEFO is applied to quantitatively analyze the interrelationships and trade-offs among system components including energy supply, electricity generation, water supply-demand, food production as well as mitigation of environmental impacts. WEFO is demonstrated to solve a hypothetical nexus management problem consistent with real-world management scenarios. Model parameters are analyzed using global sensitivity analysis and their effects on total system cost are quantified. The obtained results demonstrate how these types of analyses can be helpful for decision-makers and stakeholders to make cost-effective decisions for optimal WEF management.

Trade-offs in online purchase decisions : two empirical studies in Europe

NARCIS (Netherlands)

Odekerken-Schröder, G.; Wetzels, M.G.M.

2003-01-01

The Internet offers firms a new way to market their products and services and to interact with their end-consumers. While many firms have developed websites, very little is known about the trade-offs consumers are willing to make when making online purchases. With millions of websites competing for

Energy-delay trade-off of wireless data collection in the plane

NARCIS (Netherlands)

Mitici, M.A.; Goseling, Jasper; de Graaf, Maurits; Boucherie, Richardus J.

2014-01-01

We analyze the Pareto front of the delay of collecting data from wireless devices located in the plane according to a Poisson process and the energy needed by the devices to transmit their observations. Fundamental bounds on the energy-delay trade-off over the space of all achievable scheduling

Mutually opposing forces during locomotion can eliminate the tradeoff between maneuverability and stability

Science.gov (United States)

Cowan, Noah; Sefati, Shahin; Neveln, Izaak; Roth, Eatai; Mitchell, Terence; Snyder, James; Maciver, Malcolm; Fortune, Eric

A surprising feature of animal locomotion is that organisms typically produce substantial forces in directions other than what is necessary to move the animal through its environment, such as perpendicular to, or counter to, the direction of travel. The effect of these forces has been difficult to observe because they are often mutually opposing and therefore cancel out. Using a combination of robotic physical modeling, computational modeling, and biological experiments, we discovered that these forces serve an important role: to simplify and enhance the control of locomotion. Specifically, we examined a well-suited model system, the glass knifefish Eigenmannia virescens, which produces mutually opposing forces during a hovering behavior. By systematically varying the locomotor parameters of our biomimetic robot, and measuring the resulting forces and kinematics, we demonstrated that the production and differential control of mutually opposing forces is a strategy that generates passive stabilization while simultaneously enhancing maneuverability. Mutually opposing forces during locomotion are widespread across animal taxa, and these results indicate that such forces can eliminate the tradeoff between stability and maneuverability, thereby simplifying robotic and neural control.

Endogenous ROS levels in C. elegans under exogenous stress support revision of oxidative stress theory of life-history tradeoffs.

Science.gov (United States)

Smith, Samson W; Latta, Leigh C; Denver, Dee R; Estes, Suzanne

2014-07-24

The oxidative stress theory of life-history tradeoffs states that oxidative stress caused by damaging free radicals directly underpins tradeoffs between reproduction and longevity by altering the allocation of energetic resources between these tasks. We test this theory by characterizing the effects of exogenous oxidative insult and its interaction with thermal stress and diet quality on a suite of life-history traits and correlations in Caenorhabditis elegans nematodes. We also quantify demographic aging rates and endogenous reactive oxygen species (ROS) levels in live animals. Our findings indicate a tradeoff between investment in reproduction and antioxidant defense (somatic maintenance) consistent with theoretical predictions, but correlations between standard life-history traits yield little evidence that oxidative stress generates strict tradeoffs. Increasing oxidative insult, however, shows a strong tendency to uncouple positive phenotypic correlations and, in particular, to reduce the correlation between reproduction and lifespan. We also found that mild oxidative insult results in lower levels of endogenous ROS accompanied by hormetic changes in lifespan, demographic aging, and reproduction that disappear in combined-stress treatments--consistent with the oxidative stress theory of aging. Our findings demonstrate that oxidative stress is a direct contributor to life-history trait variation and that traditional tradeoffs are not necessary to invoke oxidative stress as a mediator of relationships between life-history traits, supporting previous calls for revisions to theory.

Exploring Tradeoffs in Demand-Side and Supply-Side Management of Urban Water Resources Using Agent-Based Modeling and Evolutionary Computation

Directory of Open Access Journals (Sweden)

Lufthansa Kanta

2015-11-01

Full Text Available Urban water supply systems may be managed through supply-side and demand-side strategies, which focus on water source expansion and demand reductions, respectively. Supply-side strategies bear infrastructure and energy costs, while demand-side strategies bear costs of implementation and inconvenience to consumers. To evaluate the performance of demand-side strategies, the participation and water use adaptations of consumers should be simulated. In this study, a Complex Adaptive Systems (CAS framework is developed to simulate consumer agents that change their consumption to affect the withdrawal from the water supply system, which, in turn influences operational policies and long-term resource planning. Agent-based models are encoded to represent consumers and a policy maker agent and are coupled with water resources system simulation models. The CAS framework is coupled with an evolutionary computation-based multi-objective methodology to explore tradeoffs in cost, inconvenience to consumers, and environmental impacts for both supply-side and demand-side strategies. Decisions are identified to specify storage levels in a reservoir that trigger: (1 increases in the volume of water pumped through inter-basin transfers from an external reservoir; and (2 drought stages, which restrict the volume of water that is allowed for residential outdoor uses. The proposed methodology is demonstrated for Arlington, Texas, water supply system to identify non-dominated strategies for an historic drought decade. Results demonstrate that pumping costs associated with maximizing environmental reliability exceed pumping costs associated with minimizing restrictions on consumer water use.

Exploring trade-offs between VMAT dose quality and delivery efficiency using a network optimization approach

International Nuclear Information System (INIS)

Salari, Ehsan; Craft, David; Wala, Jeremiah

2012-01-01

To formulate and solve the fluence-map merging procedure of the recently-published VMAT treatment-plan optimization method, called vmerge, as a bi-criteria optimization problem. Using an exact merging method rather than the previously-used heuristic, we are able to better characterize the trade-off between the delivery efficiency and dose quality. vmerge begins with a solution of the fluence-map optimization problem with 180 equi-spaced beams that yields the ‘ideal’ dose distribution. Neighboring fluence maps are then successively merged, meaning that they are added together and delivered as a single map. The merging process improves the delivery efficiency at the expense of deviating from the initial high-quality dose distribution. We replace the original merging heuristic by considering the merging problem as a discrete bi-criteria optimization problem with the objectives of maximizing the treatment efficiency and minimizing the deviation from the ideal dose. We formulate this using a network-flow model that represents the merging problem. Since the problem is discrete and thus non-convex, we employ a customized box algorithm to characterize the Pareto frontier. The Pareto frontier is then used as a benchmark to evaluate the performance of the standard vmerge algorithm as well as two other similar heuristics. We test the exact and heuristic merging approaches on a pancreas and a prostate cancer case. For both cases, the shape of the Pareto frontier suggests that starting from a high-quality plan, we can obtain efficient VMAT plans through merging neighboring fluence maps without substantially deviating from the initial dose distribution. The trade-off curves obtained by the various heuristics are contrasted and shown to all be equally capable of initial plan simplifications, but to deviate in quality for more drastic efficiency improvements. This work presents a network optimization approach to the merging problem. Contrasting the trade-off curves of the

Exploring trade-offs between VMAT dose quality and delivery efficiency using a network optimization approach.

Science.gov (United States)

Salari, Ehsan; Wala, Jeremiah; Craft, David

2012-09-07

To formulate and solve the fluence-map merging procedure of the recently-published VMAT treatment-plan optimization method, called VMERGE, as a bi-criteria optimization problem. Using an exact merging method rather than the previously-used heuristic, we are able to better characterize the trade-off between the delivery efficiency and dose quality. VMERGE begins with a solution of the fluence-map optimization problem with 180 equi-spaced beams that yields the 'ideal' dose distribution. Neighboring fluence maps are then successively merged, meaning that they are added together and delivered as a single map. The merging process improves the delivery efficiency at the expense of deviating from the initial high-quality dose distribution. We replace the original merging heuristic by considering the merging problem as a discrete bi-criteria optimization problem with the objectives of maximizing the treatment efficiency and minimizing the deviation from the ideal dose. We formulate this using a network-flow model that represents the merging problem. Since the problem is discrete and thus non-convex, we employ a customized box algorithm to characterize the Pareto frontier. The Pareto frontier is then used as a benchmark to evaluate the performance of the standard VMERGE algorithm as well as two other similar heuristics. We test the exact and heuristic merging approaches on a pancreas and a prostate cancer case. For both cases, the shape of the Pareto frontier suggests that starting from a high-quality plan, we can obtain efficient VMAT plans through merging neighboring fluence maps without substantially deviating from the initial dose distribution. The trade-off curves obtained by the various heuristics are contrasted and shown to all be equally capable of initial plan simplifications, but to deviate in quality for more drastic efficiency improvements. This work presents a network optimization approach to the merging problem. Contrasting the trade-off curves of the merging

Ensemble Modeling for Robustness Analysis in engineering non-native metabolic pathways.

Science.gov (United States)

Lee, Yun; Lafontaine Rivera, Jimmy G; Liao, James C

2014-09-01

Metabolic pathways in cells must be sufficiently robust to tolerate fluctuations in expression levels and changes in environmental conditions. Perturbations in expression levels may lead to system failure due to the disappearance of a stable steady state. Increasing evidence has suggested that biological networks have evolved such that they are intrinsically robust in their network structure. In this article, we presented Ensemble Modeling for Robustness Analysis (EMRA), which combines a continuation method with the Ensemble Modeling approach, for investigating the robustness issue of non-native pathways. EMRA investigates a large ensemble of reference models with different parameters, and determines the effects of parameter drifting until a bifurcation point, beyond which a stable steady state disappears and system failure occurs. A pathway is considered to have high bifurcational robustness if the probability of system failure is low in the ensemble. To demonstrate the utility of EMRA, we investigate the bifurcational robustness of two synthetic central metabolic pathways that achieve carbon conservation: non-oxidative glycolysis and reverse glyoxylate cycle. With EMRA, we determined the probability of system failure of each design and demonstrated that alternative designs of these pathways indeed display varying degrees of bifurcational robustness. Furthermore, we demonstrated that target selection for flux improvement should consider the trade-offs between robustness and performance. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

CREATING SHARED VALUE IN THE PRESENCE OF CONFLICTS AND TRADEOFFS: A PARADOX PERSPECTIVE ON BUSINESS AND SOCIETY

OpenAIRE

LaPierre, Karen; Wakayama, Naomi; 若山, 俊弘

2016-01-01

While business and society may engage in mutually beneficial, synergistic interactions, they also face the challenge of managing contentious, tradeoff interactions when their objectives are not aligned. In the diverse fields of studies in business and society, these two modes of business-society interactions have been conceptualized rather separately: mutual gains and synergies in concepts such as social innovation and shared value creation on one hand, and tensions and tradeoffs in studies t...

Corrective Feedback, Spoken Accuracy and Fluency, and the Trade-Off Hypothesis

Science.gov (United States)

Chehr Azad, Mohammad Hassan; Farrokhi, Farahman; Zohrabi, Mohammad

2018-01-01

The current study was an attempt to investigate the effects of different corrective feedback (CF) conditions on Iranian EFL learners' spoken accuracy and fluency (AF) and the trade-off between them. Consequently, four pre-intermediate intact classes were randomly selected as the control, delayed explicit metalinguistic CF, extensive recast, and…

Ethical Implications of Validity-vs.-Reliability Trade-Offs in Educational Research

Science.gov (United States)

Fendler, Lynn

2016-01-01

In educational research that calls itself empirical, the relationship between validity and reliability is that of trade-off: the stronger the bases for validity, the weaker the bases for reliability (and vice versa). Validity and reliability are widely regarded as basic criteria for evaluating research; however, there are ethical implications of…

Additive Representations of Preferences, A New Foundation of Decision Analysis; The Algebraic Approach

NARCIS (Netherlands)

P.P. Wakker (Peter)

1991-01-01

textabstractIn Wakker (1989, "Additive Representations of Preferences, A New Foundation of Decision Analysis"), a new foundation of decision analysis was given. The main tool was a way to derive comparisons of "tradeoffs" from ordinal preferences, with comparisons of tradeoffs revealing orderings of

Secure diversity-multiplexing tradeoff of zero-forcing transmit scheme at finite-SNR

KAUST Repository

Rezki, Zouheir

2012-04-01

In this paper, we address the finite Signal-to-Noise Ratio (SNR) Diversity-Multiplexing Tradeoff (DMT) of the Multiple Input Multiple Output (MIMO) wiretap channel, where a Zero-Forcing (ZF) transmit scheme, that intends to send the secret information in the orthogonal space of the eavesdropper channel, is used. First, we introduce the secrecy multiplexing gain at finite-SNR that generalizes the definition at high-SNR. Then, we provide upper and lower bounds on the outage probability under secrecy constraint, from which secrecy diversity gain estimates of ZF are derived. Through asymptotic analysis, we show that the upper bound underestimates the secrecy diversity gain, whereas the lower bound is tight at high-SNR, and thus its related diversity gain estimate is equal to the actual asymptotic secrecy diversity gain of the MIMO wiretap channel. © 2012 IEEE.

Synthesis of Fault-Tolerant Schedules with Transparency/Performance Trade-offs for Distributed Embedded Systems

DEFF Research Database (Denmark)

Izosimov, Viacheslav; Pop, Paul; Eles, Petru

2006-01-01

of the application. We propose a novel algorithm for the synthesis of fault-tolerant schedules that can handle the transparency/performance trade-offs imposed by the designer, and makes use of the fault-occurrence information to reduce the overhead due to fault tolerance. We model the application as a conditional...... process graph, where the fault occurrence information is represented as conditional edges and the transparent recovery is captured using synchronization nodes....... such that the operation of other processes is not affected, we call it transparent recovery. Although transparent recovery has the advantages of fault containment, improved debugability and less memory needed to store the fault-tolerant schedules, it will introduce delays that can violate the timing constraints...

Drivers, Constraints and Trade-Offs Associated with Recultivating Abandoned Cropland in Russia, Ukraine and Kazakhstan

Directory of Open Access Journals (Sweden)

Patrick Meyfroidt

2016-06-01

Full Text Available Further cropland expansion might be unavoidable to satisfy the growing demand for land- based products and ecosystem services. A crucial issue is thus to assess the trade-offs between social and ecological impacts and the benefits of converting additional land to cropland. In the former Soviet Union countries, where the transition from state-command to market-driven economies resulted in widespread agricultural land abandonment, cropland expansion may incur relatively low costs, especially compared with tropical regions. Our objectives were to quantify the drivers, constraints and trade-offs associated with recultivating abandoned cropland to assess the potentially available cropland in European Russia, western Siberia, Ukraine and Kazakhstan - the region where the vast majority of post- Soviet cropland abandonment took place. Using spatial panel regressions, we characterized the socio-economic determinants of cropland abandonment and recultivation. We then used recent maps of changes in cropland to 1 spatially characterize the socio-economic, accessibility and soil constraints associated with the recultivation of abandoned croplands and 2 investigate the environmental trade-offs regarding carbon stocks and habitat for biodiversity. Less cropland abandonment and more recultivation after 2000 occurred in areas with an increasing rural population and a younger labor force, but also improved yields. Synergies were observed between cropland recultivation and intensification over the 2000s. From 47.3 million hectares (Mha of cropland abandoned in 2009, we identified only 8.5 (7.1-17.4 Mha of potentially available cropland with low environmental tradeoffs and low to moderate socio-economic or accessibility constraints that were located on high-quality soils (Chernozems. These areas represented an annual wheat production potential of 14.3 (9.6-19.5 million tons (Mt. Conversely, 8.5 (4.2-12.4 Mha had high carbon or biodiversity trade-offs, of which 10

On the ARQ protocols over the Z-interference channels: Diversity-multiplexing-delay tradeoff

KAUST Repository

Nafea, Mohamed S.; Hamza, D.; Seddik, Karim G.; Nafie, Mohamed; Gamal, Hesham El

2012-01-01

We characterize the achievable three-dimensional tradeoff between diversity, multiplexing, and delay of the single antenna Automatic Retransmission reQuest (ARQ) Z-interference channel. Non-cooperative and cooperative ARQ protocols are adopted under

A theoretical model of water and trade

Science.gov (United States)

Dang, Qian; Konar, Megan; Reimer, Jeffrey J.; Di Baldassarre, Giuliano; Lin, Xiaowen; Zeng, Ruijie

2016-03-01

Water is an essential input for agricultural production. Agriculture, in turn, is globalized through the trade of agricultural commodities. In this paper, we develop a theoretical model that emphasizes four tradeoffs involving water-use decision-making that are important yet not always considered in a consistent framework. One tradeoff focuses on competition for water among different economic sectors. A second tradeoff examines the possibility that certain types of agricultural investments can offset water use. A third tradeoff explores the possibility that the rest of the world can be a source of supply or demand for a country's water-using commodities. The fourth tradeoff concerns how variability in water supplies influences farmer decision-making. We show conditions under which trade liberalization affect water use. Two policy scenarios to reduce water use are evaluated. First, we derive a target tax that reduces water use without offsetting the gains from trade liberalization, although important tradeoffs exist between economic performance and resource use. Second, we show how subsidization of water-saving technologies can allow producers to use less water without reducing agricultural production, making such subsidization an indirect means of influencing water use decision-making. Finally, we outline conditions under which riskiness of water availability affects water use. These theoretical model results generate hypotheses that can be tested empirically in future work.

The gender-job satisfaction paradox and the dual-earner society: Are women (still) making work-family trade-offs?

Science.gov (United States)

Grönlund, Anne; Öun, Ida

2018-01-01

Despite their disadvantaged labour market position, women consistently report higher levels of job satisfaction than men. Researchers have attributed women's higher job satisfaction to their lower expectations, arguing that gender differences will fade away as women's labour market prospects improve. Others, however, argue that women are more contented than men because their jobs satisfy a need for family adaptions. In this article, we put the hypotheses of transitions and trade-offs to a strong test, by comparing men and women with comparable human capital investments living in a country where women's employment is strongly supported by policies, practices and social norms. The relationship between gender and job satisfaction is analysed with stepwise OLS regressions. The analysis is based on a survey to newly graduated highly educated men and women in five occupations in Sweden (n ≈ 2 450). First, we show that, after controlling for a range of job characteristics, women report a higher level of job satisfaction than men. Second, although the paradox appears to be surprisingly persistent, it cannot be attributed to work-family trade-offs. Future research should consider job satisfaction more broadly in the light of gender role socialization and persistent gender inequalities.

Valuing Treatments for Parkinson Disease Incorporating Process Utility: Performance of Best-Worst Scaling, Time Trade-Off, and Visual Analogue Scales.

Science.gov (United States)

Weernink, Marieke G M; Groothuis-Oudshoorn, Catharina G M; IJzerman, Maarten J; van Til, Janine A

2016-01-01

The objective of this study was to compare treatment profiles including both health outcomes and process characteristics in Parkinson disease using best-worst scaling (BWS), time trade-off (TTO), and visual analogue scales (VAS). From the model comprising of seven attributes with three levels, six unique profiles were selected representing process-related factors and health outcomes in Parkinson disease. A Web-based survey (N = 613) was conducted in a general population to estimate process-related utilities using profile-based BWS (case 2), multiprofile-based BWS (case 3), TTO, and VAS. The rank order of the six profiles was compared, convergent validity among methods was assessed, and individual analysis focused on the differentiation between pairs of profiles with methods used. The aggregated health-state utilities for the six treatment profiles were highly comparable for all methods and no rank reversals were identified. On the individual level, the convergent validity between all methods was strong; however, respondents differentiated less in the utility of closely related treatment profiles with a VAS or TTO than with BWS. For TTO and VAS, this resulted in nonsignificant differences in mean utilities for closely related treatment profiles. This study suggests that all methods are equally able to measure process-related utility when the aim is to estimate the overall value of treatments. On an individual level, such as in shared decision making, BWS allows for better prioritization of treatment alternatives, especially if they are closely related. The decision-making problem and the need for explicit trade-off between attributes should determine the choice for a method. Copyright © 2016. Published by Elsevier Inc.

A computer simulation of a long-range CWFM radar showing the tradeoffs of performance as a function of range

Science.gov (United States)

Gordy, Robert S.; Zoledziowski, Severyn

2011-06-01

This paper describes a study of the operation of a long range CWFM radar using "System View" software for modeling and simulation. The System View software is currently offered by Agilent. The models that were studied include: a model illustrating the basic principle of operation of the CWFM radar, the range resolution of the radar, the effect of long range processing and the resultant approach with the tradeoff of detected range resolution due to Doppler frequency shift as a function of range distance. The study was performed as part of the design of an airborne CWFM radar. The radar can be designed with a single antenna or a dual antenna. The dual antenna approach is presented in this paper.

Controversy in the classroom: How eighth-grade and undergraduate students reason about tradeoffs of genetically modified food

Science.gov (United States)

Seethaler, Sherry Lynn

Current issues in science provide a rich context for learning because they can involve complex tradeoffs that cut across traditional disciplinary boundaries. Despite this potential benefit, and the need for citizens to make decisions about such issues, science controversy remains rare in the classroom. Consequently, there is much unknown about how students make sense of complex, multidisciplinary science. This research examined eighth-grade (n = 190) and undergraduate (n = 9) students' reasoning about tradeoffs in the genetically modified food controversy (main study). To extend the findings from the main study, undergraduate students' reasoning was followed as they learned about ten additional science controversies (extension). The studies took place in the context of curricula designed on the basis of the Scaffolded Knowledge Integration Framework, which posits a set of design principles that help students form a rich, integrated network of ideas about a topic. Two new methodologies were developed for this work. The Embedded Perspective of Science Controversy was used to study students' integration of content in their written arguments (main study) and oral and written questions (extension). The Perspective views science controversy as a set of nested levels, where tradeoffs are one of the levels, but connecting to other levels (underlying scientific details, bigger picture context, etc.) is important for the weighing of tradeoffs. A scheme based on Toulmin's (1958) work on argumentation provided a way of comparing the structure of students' arguments. As indicated by pre and post test scores, the curriculum helped both eighth-grade students (t = 11.7, p genetically modified food. In their final papers, both eighth-grade and undergraduate students presented evidence for and against their positions, in contrast with prior literature showing individuals have difficulty coming up with evidence against their positions. The students were also moving across the levels

The Effect of Forest Management Strategy on Carbon Storage and Revenue in Western Washington: A Probabilistic Simulation of Tradeoffs.

Science.gov (United States)

Fischer, Paul W; Cullen, Alison C; Ettl, Gregory J

2017-01-01

The objectives of this study are to understand tradeoffs between forest carbon and timber values, and evaluate the impact of uncertainty in improved forest management (IFM) carbon offset projects to improve forest management decisions. The study uses probabilistic simulation of uncertainty in financial risk for three management scenarios (clearcutting in 45- and 65-year rotations and no harvest) under three carbon price schemes (historic voluntary market prices, cap and trade, and carbon prices set to equal net present value (NPV) from timber-oriented management). Uncertainty is modeled for value and amount of carbon credits and wood products, the accuracy of forest growth model forecasts, and four other variables relevant to American Carbon Registry methodology. Calculations use forest inventory data from a 1,740 ha forest in western Washington State, using the Forest Vegetation Simulator (FVS) growth model. Sensitivity analysis shows that FVS model uncertainty contributes more than 70% to overall NPV variance, followed in importance by variability in inventory sample (3-14%), and short-term prices for timber products (8%), while variability in carbon credit price has little influence (1.1%). At regional average land-holding costs, a no-harvest management scenario would become revenue-positive at a carbon credit break-point price of $14.17/Mg carbon dioxide equivalent (CO 2 e). IFM carbon projects are associated with a greater chance of both large payouts and large losses to landowners. These results inform policymakers and forest owners of the carbon credit price necessary for IFM approaches to equal or better the business-as-usual strategy, while highlighting the magnitude of financial risk and reward through probabilistic simulation. © 2016 Society for Risk Analysis.

Photovoltaic subsystem optimization and design tradeoff study. Final report

Energy Technology Data Exchange (ETDEWEB)

Stolte, W.J.

1982-03-01

Tradeoffs and subsystem choices are examined in photovoltaic array subfield design, power-conditioning sizing and selection, roof- and ground-mounted structure installation, energy loss, operating voltage, power conditioning cost, and subfield size. Line- and self-commutated power conditioning options are analyzed to determine the most cost-effective technology in the megawatt power range. Methods for reducing field installation of flat panels and roof mounting of intermediate load centers are discussed, including the cost of retrofit installations.

Engineering report. Part 2: NASA wheel and brake material tradeoff study for space shuttle type environmental requirements

Science.gov (United States)

Bok, L. D.

1973-01-01

The study included material selection and trade-off for the structural components of the wheel and brake optimizing weight vs cost and feasibility for the space shuttle type application. Analytical methods were used to determine section thickness for various materials, and a table was constructed showing weight vs. cost trade-off. The wheel and brake were further optimized by considering design philosophies that deviate from standard aircraft specifications, and designs that best utilize the materials being considered.

Quantifying women's stated benefit-risk trade-off preferences for IBS treatment outcomes.

Science.gov (United States)

Johnson, F Reed; Hauber, A Brett; Ozdemir, Semra; Lynd, Larry

2010-01-01

The Food and Drug Administration, currently, is exploring quantitative benefit-risk methods to support regulatory decision-making. A scientifically valid method for assessing patients' benefit-risk trade-off preferences is needed to compare risks and benefits in a common metric. The study aims to quantify the maximum acceptable risk (MAR) of treatment-related adverse events (AEs) that women with diarrhea-predominant irritable bowel syndrome (IBS) are willing to accept in exchange for symptom relief. A stated-choice survey was used to elicit trade-off preferences among constructed treatment profiles, each defined by symptom severity and treatment-related AEs. Symptom attributes included frequency of abdominal pain and discomfort, frequency of diarrhea, and frequency of urgency. AE attributes included frequency of mild-to-moderate constipation and the risk of four possible serious AEs. A Web-enabled survey was administered to 589 female US residents at least 18 years of age with a self-reported diagnosis of diarrhea-predominant IBS. Preference weights and MAR were estimated using mixed-logit methods. SUBJECTS were willing to accept higher risks of serious AEs in return for treatments offering better symptom control. For an improvement from the lowest to the highest of four benefit levels, subjects were willing to tolerate a 2.65% increase in impacted-bowel risk, but only a 1.34% increase in perforated-bowel risk. Variation in MARs across AE types is consistent with the relative seriousness of the AEs. Stated-preference methods offer a scientifically valid approach to quantifying benefit-risk trade-off preferences that can be used to inform regulatory decision-making.

Modeling an emissions peak in China around 2030: Synergies or trade-offs between economy, energy and climate security

Directory of Open Access Journals (Sweden)

Qi-Min Chai

2014-12-01

Full Text Available China has achieved a political consensus around the need to transform the path of economic growth toward one that lowers carbon intensity and ultimately leads to reductions in carbon emissions, but there remain different views on pathways that could achieve such a transformation. The essential question is whether radical or incremental reforms are required in the coming decades. This study explores relevant pathways in China beyond 2020, particularly modeling the major target choices of carbon emission peaking in China around 2030 as China-US Joint Announcement by an integrated assessment model for climate change IAMC based on carbon factor theory. Here scenarios DGS-2020, LGS2025, LBS-2030 and DBS-2040 derived from the historical pathways of developed countries are developed to access the comprehensive impacts on the economy, energy and climate security for the greener development in China. The findings suggest that the period of 2025–2030 is the window of opportunity to achieve a peak in carbon emissions at a level below 12 Gt CO2 and 8.5 t per capita by reasonable trade-offs from economy growth, annually −0.2% in average and cumulatively −3% deviation to BAU in 2030. The oil and natural gas import dependence will exceed 70% and 45% respectively while the non-fossil energy and electricity share will rise to above 20% and 45%. Meantime, the electrification level in end use sectors will increase substantially and the electricity energy ratio approaching 50%, the labor and capital productivity should be double in improvements and the carbon intensity drop by 65% by 2030 compared to the 2005 level, and the cumulative emission reductions are estimated to be more than 20 Gt CO2 in 2015–2030.

The Child Quantity-Quality Trade-Off During the Industrial Revolution in England

DEFF Research Database (Denmark)

Klemp, Marc; Weisdorf, Jacob L.

We take Gary Becker's child quantity-quality trade-off hypothesis to the historical record, investigating the causal link from family size to the literacy status of offspring using data from Anglican parish registers, c. 1700-1830. Extraordinarily forhistorical data, the parish records enable us ...

Opposition multiple objective symbiotic organisms search (OMOSOS for time, cost, quality and work continuity tradeoff in repetitive projects

Directory of Open Access Journals (Sweden)

Duc-Hoc Tran

2018-04-01

Full Text Available Construction managers often face with projects containing multiple units wherein activities repeat from unit to unit. Therefore effective resource management is crucial in terms of project duration, cost and quality. Accordingly, researchers have developed several models to aid planners in developing practical and near-optimal schedules for repetitive projects. Despite their undeniable benefits, such models lack the ability of pure simultaneous optimization because existing methodologies optimize the schedule with respect to a single factor, to achieve minimum duration, total cost, resource work breaks or various combinations, respectively. This study introduces a novel approach called “opposition multiple objective symbiotic organisms search” (OMOSOS for scheduling repetitive projects. The proposed algorithm used an opposition-based learning technique for population initialization and for generation jumping. Further, this study integrated a scheduling module (M1 to determine all project objectives including time, cost, quality and interruption. The proposed algorithm was implemented on two application examples in order to demonstrate its capabilities in optimizing the scheduling of repetitive construction projects. The results indicate that the OMOSOS approach is a powerful optimization technique and can assist project managers in selecting appropriate plan for project. Keywords: Symbiotic organisms search, Multi-objective analysis, Resource tradeoff, Schedules, Repetitive

Two sides of a coin: host-plant synchrony fitness trade-offs in the population dynamics of the western spruce budworm.

Science.gov (United States)

Régnière, Jacques; Nealis, Vincent G

2018-02-01

Conifer-feeding budworms emerge from overwintering sites as small larvae in early spring, several days before budburst, and mine old needles. These early-emerging larvae suffer considerable mortality during this foraging period as they disperse in search of available, current-year buds. Once buds flush, surviving budworms construct feeding shelters and must complete maturation before fresh host foliage senesces and lignifies later in the summer. Late-developing larvae suffer greater mortality and survivors have lower fecundity when feeding on older foliage. Thus, there is a seasonal trade-off in fitness associated with host synchrony: early-emerging budworms have a greater risk of mortality during spring dispersal but gain better access to the most nutritious foliage, while, on the other hand, late-emerging larvae incur a lower risk during the initial foraging period but must contend with rapidly diminishing resource quality at the end of the feeding period. We investigate the balance that results from these early-season and late-season synchrony fitness trade-offs using the concept of the phenological window. Parameters associated with the variation in the phenological window are used to estimate generational fitness as a function of host-plant synchrony. Because defoliation modifies these relationships, it is also included in the analysis. We show that fitness trade-offs characterizing the phenological window result in a robust synchrony relationship between budworm and host plant over a wide geographic range in southern British Columbia, Canada. © 2016 Her Majesty the Queen in Right of Canada Insect Science © 2016 Institute of Zoology, Chinese Academy of Sciences.

An innovative cross-sectoral method for implementation of trade-off adaptation strategy assessment under climate change

Science.gov (United States)

Tsao, Jung-Hsuan; Tung, Ching-Pin; Liu, Tzu-Ming

2014-05-01

Climate change will increase sharp risks to the water and food supply in coming decades. Although impact assessment and adaptation evaluation has been discussed a lot in recent years, the importance of adaptation implement should not be ignored. In Taiwan, and elsewhere, fallow is an option of adaptation strategy under climate change. Fallow would improve the water scarcity of domestic use, but the food security might be threatened. The trade-off effects of adaptation actions are just like the side effects of medicine which cannot be avoided. Thus, managing water resources with an integrated approach will be urgent. This study aims to establish a cross-sectoral framework for implementation the trade-off adaptation strategy. Not only fallow, but also other trade-off strategy like increasing the percentage of national grain self-sufficiency would be analyzed by a rational decision process. The recent percentage of grain self-sufficiency in Taiwan is around 32, which was decreasing from 53 thirty years ago. Yet, the goal of increasing grain self-sufficiency means much more water must be used in agriculture. In that way, domestic users may face the water shortage situation. Considering the conflicts between water supply and food security, the concepts from integrative negotiation are appropriate to apply. The implementation of trade-off adaptation strategies needs to start by quantifying the utility of water supply and food security were be quantified. Next, each side's bottom line can be found by BATNA (Best Alternative to a Negotiated Agreement) and ZOPA (Zone of Possible Agreement). ZOPA provides the entire possible outcomes, and BATNA ensures the efficiency of adaptation actions by moving along with Pareto frontier. Therefore, the optimal percentage of fallow and grain self-sufficiency can be determined. Furthermore, BATNA also provides the pathway step by step which can be a guideline of adaptation strategies. This framework allows analysts and stakeholder to

Balancing the Trade-off Between Learning Prospects and Spillover Risks

DEFF Research Database (Denmark)

Perri, Alessandra; Andersson, Ulf; Nell, Phillip Christopher

2013-01-01

This paper investigates local vertical linkages of foreign subsidiaries and the dual role of such linkages as conduits for learning as well as potential channels for spillovers to competitors. On the basis of data from 97 subsidiaries, we analyze the quality of such linkages under varying levels ...... find a curvilinear relationship between the extent of competitive pressure and the quality of local linkages confirming our argument of a trade-off between learning prospects and spillover risks. Furthermore, the level of subsidiary capabilities moderates this relationship.......This paper investigates local vertical linkages of foreign subsidiaries and the dual role of such linkages as conduits for learning as well as potential channels for spillovers to competitors. On the basis of data from 97 subsidiaries, we analyze the quality of such linkages under varying levels...... of competition and subsidiary capabilities. Our theoretical development and the results from the analysis document a far more complex and dynamic relationship between levels of competition and MNCs’ local participation in knowledge intensive activities, i.e. learning and spillovers, than previous studies do. We...

Using measurable dosimetric quantities to characterize the inter-structural tradeoff in inverse planning

Science.gov (United States)

Liu, Hongcheng; Dong, Peng; Xing, Lei

2017-08-01

Traditional inverse planning relies on the use of weighting factors to balance the conflicting requirements of different structures. Manual trial-and-error determination of weighting factors has long been recognized as a time-consuming part of treatment planning. The purpose of this work is to develop an inverse planning framework that parameterizes the dosimetric tradeoff among the structures with physically meaningful quantities to simplify the search for clinically sensible plans. In this formalism, instead of using weighting factors, the permissible variation range of the prescription dose or dose volume histogram (DVH) of the involved structures are used to characterize the ‘importance’ of the structures. The inverse planning is then formulated into a convex feasibility problem, called the dosimetric variation-controlled model (DVCM), whose goal is to generate plans with dosimetric or DVH variations of the structures consistent with the pre-specified values. For simplicity, the dosimetric variation range for a structure is extracted from a library of previous cases which possess similar anatomy and prescription. A two-phase procedure (TPP) is designed to solve the model. The first phase identifies a physically feasible plan to satisfy the prescribed dosimetric variation, and the second phase automatically improves the plan in case there is room for further improvement. The proposed technique is applied to plan two prostate cases and two head-and-neck cases and the results are compared with those obtained using a conventional CVaR approach and with a moment-based optimization scheme. Our results show that the strategy is able to generate clinically sensible plans with little trial and error. In all cases, the TPP generates a very competitive plan as compared to those obtained using the alternative approaches. Particularly, in the planning of one of the head-and-neck cases, the TPP leads to a non-trivial improvement in the resultant dose distribution�