performance trade-off studies: Topics by WorldWideScience.org

Sample records for performance trade-off studies

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....
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).
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
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.
Trade-off study of liquid-metal self-cooled blankets

International Nuclear Information System (INIS)

Gohar, Y.

1986-01-01

A trade-off study of liquid-metal self-cooled blankets was carried out to define the performance of these blankets with respect to the main functions in a fusion reactor, and to determine the potential to operate at the maximum possible values of the performance parameters. The main purpose is to improve the reactor economics by maximizing the blanket energy multiplication factor, reduce the capital cost of the reactor, and satisfy the design requirements. The main parameters during the course of the study were the tritium breeding ratio (TBR), the blanket energy multiplication factor, the energy fraction lost to the shield, the 6 Li enrichment in the breeder material, the total blanket thickness, the reflector material selection, and the compositions of the different blanket zones. Also, the impact of different reactor design choices on the performance parameters was analyzed. The effect of the impurity control system (limiter or divertor), the material choice for the limiter, the elimination of tritium breeding from the inboard section of tokamak reactors, the coolant choice for the nonbreeding inboard blanket, and the neutron source distribution were part of the trade-off study. In addition, tritium breeding benchmark calculations were performed to study the impact of the use of different transport codes and nuclear data libraries. The importance and the negative effect of high TBR on the energy multiplication motivated the benchmark calculations
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
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.
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.
Learning about social-ecological trade-offs

Directory of Open Access Journals (Sweden)

Diego Galafassi

2017-03-01

Full Text Available Trade-offs are manifestations of the complex dynamics in interdependent social-ecological systems. Addressing trade-offs involves challenges of perception due to the dynamics of interdependence. We outline the challenges associated with addressing trade-offs and analyze knowledge coproduction as a practice that may contribute to tackling trade-offs in social-ecological systems. We discuss this through a case study in coastal Kenya in which an iterative knowledge coproduction process was facilitated to reveal social-ecological trade-offs in the face of ecological and socioeconomic change. Representatives of communities, government, and NGOs attended two integrative workshops in which methods derived from systems thinking, dialogue, participatory modeling, and scenarios were applied to encourage participants to engage and evaluate trade-offs. Based on process observation and interviews with participants and scientists, our analysis suggests that this process lead to increased appreciation of interdependences and the way in which trade-offs emerge from complex dynamics of interdependent factors. The process seemed to provoke a reflection of knowledge assumptions and narratives, and management goals for the social-ecological system. We also discuss how stakeholders link these insights to their practices.
Traits traded off

NARCIS (Netherlands)

Rueffler, Claus

2006-01-01

The course of evolution is restricted by constraints. A special type of constraint is a trade-off where different traits are negatively correlated. In this situation a mutant type that shows an improvement in one trait suffers from a decreased performance through another trait. In a fixed fitness
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.
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
Of Uberfleas and Krakens: Detecting Trade-offs Using Mixed Models.

Science.gov (United States)

Careau, Vincent; Wilson, Robbie S

2017-08-01

All animals experience performance trade-offs as they complete tasks such as capturing prey, defending territories, acquiring mates, and escaping predators. Why then, is it so hard to detect performance trade-offs at the whole-organismal level? Why do we sometimes even obtain positive correlations between two performance traits that are predicted to be negatively associated? Here we explore two plausible explanations. First, most analyses are based on individual maximal values (i.e., personal best), which could introduce a bias in the correlation estimates. Second, phenotypic correlations alone may be poor indicators of a trade-off when contrasting processes occur at the among- versus within-individual levels. One such scenario is the "big houses big cars" model developed in life-history theory to explain the existence of "uberfleas" that are superior in all regards (because they acquire more resources than others). We highlight that the exact opposite scenario might occur for performance trade-offs, where among-individual trade-offs may be masked by within-individual changes in physical condition. One of the best ways to test among these alternative scenarios is to collect repeated pairs of performance traits and analyze them using multivariate mixed models (MMMs). MMMs allow straightforward and simultaneous examination of trait correlations at the among- and within-individual levels. We use a simple simulation tool (SQuID package in R) to create a population of Krakens, a mythical giant squid-like sea creature whose morphology generates a performance trade-off between swimming speed and strength or ability to sink ships. The simulations showed that using individual maximum values introduces a bias that is particularly severe when individuals differ in the number of repeated samples (ntrial). Finally, we show how MMMs can help detect performance (or any other type of) trade-offs and offer additional insights (e.g., help detect plasticity integration). We hope
A Reference-Dependent Regret Model for Deterministic Trade-off Studies

Energy Technology Data Exchange (ETDEWEB)

Kujawski, Edouard

2005-02-25

Today's typical multi-criteria decision analysis is based on classical expected utility theory that assumes a mythical ''Rational Individual'' immune to psychological influences such as anticipated regret. It is therefore in conflict with rational individuals who trade-off some benefits and forgo the alternative with the highest total classical utility for a more balanced alternative in order to reduce their levels of anticipated regret. This paper focuses on decision making under certainty. It presents a reference-dependent regret model (RDRM) in which the level of regret that an individual experiences depends on the absolute values rather than the differences of the utilities of the chosen and forgone alternatives. The RDRM best choice may differ from the conventional linear additive utility model, the analytic hierarchy process, and the regret theory of Bell and Loomes and Sugden. Examples are presented that indicate that RDRM is the better predictive descriptor for decision making under certainty. RDRM satisfies transitivity of the alternatives under pairwise comparisons and models rank reversal consistent with observed reasonable choices under dynamic or distinct situations. Like regret theory, the RDRM utilities of all the alternatives under consideration are interrelated. For complex trade-off studies regret is incorporated as an element of a cost-utility-regret analysis that characterizes each alternative in terms of its monetary cost, an aggregate performance utility, and a regret value. This provides decision makers adequate information to compare the alternatives and depending on their values they may trade-off some performance and/or cost to avoid high levels of regret. The result is a well-balanced alternative often preferred by reasonable decision makers to the optimal choice of classical multi-attribute utility analysis. The model can readily be extended to incorporate rejoicing to suit decision makers who seek it. The
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
Trade-offs across space, time, and ecosystem services

Science.gov (United States)

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
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).
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.

A Goal Oriented Approach for Modeling and Analyzing Security Trade-Offs

Science.gov (United States)

Elahi, Golnaz; Yu, Eric

In designing software systems, security is typically only one design objective among many. It may compete with other objectives such as functionality, usability, and performance. Too often, security mechanisms such as firewalls, access control, or encryption are adopted without explicit recognition of competing design objectives and their origins in stakeholder interests. Recently, there is increasing acknowledgement that security is ultimately about trade-offs. One can only aim for "good enough" security, given the competing demands from many parties. In this paper, we examine how conceptual modeling can provide explicit and systematic support for analyzing security trade-offs. After considering the desirable criteria for conceptual modeling methods, we examine several existing approaches for dealing with security trade-offs. From analyzing the limitations of existing methods, we propose an extension to the i* framework for security trade-off analysis, taking advantage of its multi-agent and goal orientation. The method was applied to several case studies used to exemplify existing approaches.
Trade-Off Study for an STC 70 W Stirling Engine

Science.gov (United States)

Qiu, Songgang; Peterson, Allen A.; Augenblick, Jack E.

2005-02-01

A high-efficiency, low-weight free-piston Stirling generator, RG-70L, has been conceptually designed. This paper reports the detailed trade-off study of newly designed RG-70L. The trades of operating frequency and piston/displacer strokes on Stirling convertor mass and efficiency are discussed. This paper shows how the operating frequency and strokes were optimized based on the trades. Losses associated with increased frequency were fully investigated and the results are discussed in the paper. Various optional linear alternator configurations are also presented and the estimated masses are reported.
Examining Impulse-Variability Theory and the Speed-Accuracy Trade-Off in Children's Overarm Throwing Performance.

Science.gov (United States)

Molina, Sergio L; Stodden, David F

2018-04-01

This study examined variability in throwing speed and spatial error to test the prediction of an inverted-U function (i.e., impulse-variability [IV] theory) and the speed-accuracy trade-off. Forty-five 9- to 11-year-old children were instructed to throw at a specified percentage of maximum speed (45%, 65%, 85%, and 100%) and hit the wall target. Results indicated no statistically significant differences in variable error across the target conditions (p = .72), failing to support the inverted-U hypothesis. Spatial accuracy results indicated no statistically significant differences with mean radial error (p = .18), centroid radial error (p = .13), and bivariate variable error (p = .08) also failing to support the speed-accuracy trade-off in overarm throwing. As neither throwing performance variability nor accuracy changed across percentages of maximum speed in this sample of children as well as in a previous adult sample, current policy and practices of practitioners may need to be reevaluated.
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.
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.
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
Co-existence of multiple trade-off currencies shapes evolutionary outcomes.

Directory of Open Access Journals (Sweden)

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
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.
Intermodal Freight Transport on the Right Track? Environmental and economic performances and their trade-off

International Nuclear Information System (INIS)

Kim, Nam Seok

2010-01-01

This dissertation aims to evaluate environmental and economic performances of an intermodal freight transport system and to estimate the trade-off between CO2 emissions, which is presented as an indicator of environmental performance, and freight costs, which indicate the economic performance of the intermodal freight system. The truck-only system is always regarded as the counterpart of the intermodal freight system in this dissertation. To examine the environmental performance of the intermodal freight system, CO2 emissions generated from all the processes in the intermodal chain, such as pre-haulage and post-haulage, long distance haulage, and transshipment, are estimated considering different sources that generate electricity and transmission loss of electricity (Chapters 3 and 4). To examine the economic performance of the system, two approaches are considered: (1) finding the intermodal breakeven distance for which the intermodal system is more competitive than the truck-only system (Chapter 5); (2) examining the economies of scale in the intermodal network and finding the route/system choice that minimizes the total freight transportation costs (Chapter 6). Finally, this dissertation attempts to find the trade-off between CO2 emissions (representing the environmental performance) and freight transportation cost (representing the economic performance) (Chapter 7)
Trade Off Relevance Dan Reliability: Isu Ifrs

OpenAIRE

Mahmudah, Hadi

2013-01-01

Financial reports containing qualitative characteristic that are useful for usernya.For a long time believed to be the existence of trade off between characteristic of qualitative relevance and reliability. Trade off due to the fact that the use of the method of measurement historical cost and fair value. Trade off occur because of the interests of for the purpose of the preparation of reports on finance. Accountability for the purpose of the measurement of the cost of historical still reliab...
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.
Exercise training reveals trade-offs between endurance performance and immune function, but does not influence growth, in juvenile lizards.

Science.gov (United States)

Husak, Jerry F; Roy, Jordan C; Lovern, Matthew B

2017-04-15

Acquired energetic resources allocated to a particular trait cannot then be re-allocated to a different trait. This often results in a trade-off between survival and reproduction for the adults of many species, but such a trade-off may be manifested differently in juveniles not yet capable of reproduction. Whereas adults may allocate resources to current and/or future reproduction, juveniles can only allocate to future reproduction. Thus, juveniles should allocate resources toward traits that increase survival and their chances of future reproductive success. We manipulated allocation of resources to performance, via endurance exercise training, to examine trade-offs among endurance capacity, immune function and growth in juvenile green anole lizards. We trained male and female captive anoles on a treadmill for 8 weeks, with increasing intensity, and compared traits with those of untrained individuals. Our results show that training enhanced endurance capacity equally in both sexes, but immune function was suppressed only in females. Training had no effect on growth, but males had higher growth rates than females. Previous work showed that trained adults have enhanced growth, so juvenile growth is either insensitive to stimulation with exercise, or they are already growing at maximal rates. Our results add to a growing body of literature indicating that locomotor performance is an important part of life-history trade-offs that are sex and age specific. © 2017. Published by The Company of Biologists Ltd.
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.
Reproduction alters oxidative status when it is traded-off against longevity.

Science.gov (United States)

Beaulieu, Michaël; Geiger, Rina E; Reim, Elisabeth; Zielke, Luisa; Fischer, Klaus

2015-07-01

Oxidative stress has been proposed to mediate one of the most important aspects of life-history evolution: the trade-off between reproduction and self-maintenance. However, empirical studies have cast doubt on the generality of this intriguing notion. Here, we hypothesize that reproduction alters oxidative status only when a trade-off between reproduction and self-maintenance occurs. Accordingly, in female Bicyclus anynana butterflies, we found that reproduction affected oxidative markers only under challenging thermal conditions that made the trade-off between reproduction and longevity emerge. Interestingly, under such conditions, butterflies favored longevity over reproduction, suggesting that self-maintenance mechanisms were activated. Accordingly, butterflies reproducing under challenging thermal conditions exhibited enhanced antioxidant defenses and stable oxidative damage. Altogether, our results indicate that a trade-off between reproduction and self-maintenance is indeed a necessary condition for reproduction to alter oxidative status, and that the effects of such a trade-off on oxidative status depend on whether priority is given to self-maintenance or reproduction. Assessing the existence of the trade-off between self-maintenance and reproduction, and whether self-maintenance is prioritized relative to reproduction is therefore crucial for understanding variation in oxidative status in reproducing animals, which may clarify the general implication of oxidative stress in the resolution of life-history trade-offs. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.
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
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.
Performance and Cost Trade-off in Tracking Area Reconfiguration: A Pareto-optimization Approach

OpenAIRE

Modarres Razavi, Sara; Yuan, Di; Gunnarsson, Fredrik; Moe, Johan

2012-01-01

Tracking Area (TA) design is one of the key tasks in location management of Long Term Evolution (LTE) networks. TA enables to trace and page User Equipments (UEs). As UEs distribution and mobility patterns change over time, TA design may have to undergo revisions. For revising the TA design, the cells to be reconfigured typically have to be temporary torn down. Consequently, this will result in service interruption and “cost”. There is always a trade-off between the performance in terms of th...
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.
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.

Overview of homogeneous versus heterogeneous core configuration trade-off studies

International Nuclear Information System (INIS)

Chang, Y.I.

1982-01-01

The most significant development in core design trend in the U.S. LMFBR program has been the increased attention given to the heterogeneous core design concept. In recent years, numerous core configuration trade-off studies have been carried out to quantify advantages and disadvantages of the heterogeneous concept relative to the homogeneous concept, and a consensus is emerging among the U.S. core designers. It appears that the technical and economic performance differences between homogeneous and heterogeneous core designs are very small; however, the heterogeneous concept provides a definite safety/licensing advantage. he technical and economic performance comparison between homogeneous and heterogeneous core configurations is difficult to quantify. In fact, in most cases, the perceived advantages and/or disadvantages are dictated by the consistency in the comparison (optimized for one concept versus non-optimized for the other, etc.) rather than by any inherent differences. Some of the technical and economic issues relevant to the homogeneous versus heterogeneous comparison are summarized
Overview of homogeneous versus heterogeneous core configuration trade-off studies

Energy Technology Data Exchange (ETDEWEB)

Chang, Y I [Applied Physics Division, Argonne National Laboratory, Argonne, IL (United States)

1982-01-01

The most significant development in core design trend in the U.S. LMFBR program has been the increased attention given to the heterogeneous core design concept. In recent years, numerous core configuration trade-off studies have been carried out to quantify advantages and disadvantages of the heterogeneous concept relative to the homogeneous concept, and a consensus is emerging among the U.S. core designers. It appears that the technical and economic performance differences between homogeneous and heterogeneous core designs are very small; however, the heterogeneous concept provides a definite safety/licensing advantage. he technical and economic performance comparison between homogeneous and heterogeneous core configurations is difficult to quantify. In fact, in most cases, the perceived advantages and/or disadvantages are dictated by the consistency in the comparison (optimized for one concept versus non-optimized for the other, etc.) rather than by any inherent differences. Some of the technical and economic issues relevant to the homogeneous versus heterogeneous comparison are summarized.
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...
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...
Trade off study on different envelope detectors for B-mode imaging

DEFF Research Database (Denmark)

Schlaikjer, Malene; Bagge, J. P.; Jensen, Jørgen Arendt

2003-01-01

sum of the real and imaginary signals. The four detectors were evaluated on in-vivo data acquired with a B-K Medical 2102 scanner interfaced to the sampling system RASMINE. Three data sets were acquired with three different center frequencies. Hundred images were acquired as the transducer was moved......Generation of B-mode images involves envelope detection of the RF-signals. Various detection algorithms are available. A trade off between performance, price, and complexity determines the choice of algorithm in an ultrasound system. A Hilbert Transform (HT) and a subsequent computation...... of the magnitude give the ideal envelope, but the approach (IDE) is expensive and complex. A rectifier (REC) is a simple, low-cost solution, but the performance is severely degraded (especially in dynamic imaging). This study has investigated the possibility of providing a detector with a complexity and cost close...
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.
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....
Diversity-Multiplexing-Nulling Trade-Off Analysis of Multiuser MIMO System for Intercell Interference Coordination

Directory of Open Access Journals (Sweden)

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

Science.gov (United States)

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

Science.gov (United States)

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
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.
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.

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
Trade-off study of liquid metal self-cooled blankets

International Nuclear Information System (INIS)

Gohar, Y.

1986-01-01

A trade-off study of liquid metal self-cooled blankets was carried out to define the performance of these blankets and to determine the potential to operate at the maximum possible values of the performance parameters. The main parameters considered during the course of this study were the tritium breeding ratio (TBR), the blanket energy multiplication factor, the energy fraction lost to the shield, the lithium-6 enrichment in the breeder material, the total blanket thickness, the reflector material selection, and the compositions of the different blanket zones. The primary results of the study are as follows: a) the lithium-lead blanket achieves a higher TBR with a smaller blanket thickness relative to the lithium blanket; b) the lithium blanket generates more energy per fusion neutron relative to the lithium-lead blanket; c) among the possible reflector materials, the carbon reflector produces the highest TBR; d) the high-Z reflector materials (Mo, Cu, W, or steel) generate more energy per fusion neutron and produce smaller TBRs relative to the carbon reflector; e) lithium-6 enrichment is required for the lithium-lead blanket to reduce the total blanket thickness; and f) the energy deposition per fusion neutron reaches a saturation as the blanket thickness, the fraction of the high-Z material in the reflector, or the reflector zone thickness increases (this allows one to design the blanket for a specific TBR without reducing the energy production)
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.
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...
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.
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.
Executing Bag of Distributed Tasks on the Cloud : investigating the trade-offs between performance and cost

OpenAIRE

Thai, Long; Varghese, Blesson; Barker, Adam

2014-01-01

This research is supported by the EPSRC grant ‘Working Together: Constraint Programming and Cloud Computing’ (EP/K015745/1), a Royal Society Industry Fellowship ‘Bringing Science to the Cloud’, an EPSRC Impact Acceleration Grant (IAA) and an Amazon Web Services (AWS) Education Research Grant. Date of Acceptance: 20/09/2014 Bag of Distributed Tasks (BoDT) can benefit from decentralised execution on the Cloud. However, there is a trade-off between the performance that can be achieved by empl...
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
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.
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.
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-...
Scheduling and Optimization of Fault-Tolerant Embedded Systems with Transparency/Performance Trade-Offs

DEFF Research Database (Denmark)

Izosimov, Viacheslav; Pop, Paul; Eles, Petru

2012-01-01

In this article, we propose a strategy for the synthesis of fault-tolerant schedules and for the mapping of fault-tolerant applications. Our techniques handle transparency/performance trade-offs and use the faultoccurrence information to reduce the overhead due to fault tolerance. Processes...... and messages are statically scheduled, and we use process reexecution for recovering from multiple transient faults. We propose a finegrained transparent recovery, where the property of transparency can be selectively applied to processes and messages. Transparency hides the recovery actions in a selected part...... of the application so that they do not affect the schedule of other processes and messages. While leading to longer schedules, transparent recovery has the advantage of both improved debuggability and less memory needed to store the faulttolerant schedules....
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.
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.
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.
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
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.
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...

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...
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...
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.
Trade-Off Analysis between Concerns Based on Aspect-Oriented Requirements Engineering

Science.gov (United States)

Laurito, Abelyn Methanie R.; Takada, Shingo

The identification of functional and non-functional concerns is an important activity during requirements analysis. However, there may be conflicts between the identified concerns, and they must be discovered and resolved through trade-off analysis. Aspect-Oriented Requirements Engineering (AORE) has trade-off analysis as one of its goals, but most AORE approaches do not actually offer support for trade-off analysis; they focus on describing concerns and generating their composition. This paper proposes an approach for trade-off analysis based on AORE using use cases and the Requirements Conflict Matrix (RCM) to represent compositions. RCM shows the positive or negative effect of non-functional concerns over use cases and other non-functional concerns. Our approach is implemented within a tool called E-UCEd (Extended Use Case Editor). We also show the results of evaluating our tool.
Balancing Biomechanical Constraints: Optimal Escape Speeds When There Is a Trade-off between Speed and Maneuverability.

Science.gov (United States)

Clemente, C J; Wilson, R S

2015-12-01

The ability for prey to escape a pursuing predator is dependent both on the prey's speed away from the threat and on their ability to rapidly change directions, or maneuverability. Given that the biomechanical trade-off between speed and maneuverability limits the simultaneous maximization of both performance traits, animals should not select their fastest possible speeds when running away from a pursuing predator but rather a speed that maximizes the probability of successful escape. We explored how variation in the relationship between speed and maneuverability-or the shape of the trade-off-affects the optimal choice of speed for escaping predators. We used tablet-based games that simulated interactions between predators and prey (human subjects acting as predators attempting to capture "prey" moving across a screen). By defining a specific relationship between speed and maneuverability, we could test the survival of each of the possible behavioral choices available to this phenotype, i.e., the best combination of speed and maneuverability for prey fitness, based on their ability to escape. We found that the shape of the trade-off function affected the prey's optimal speed for success in escaping, the prey's maximum performance in escaping, and the breadth of speeds over which the prey's performance was high. The optimal speed for escape varied only when the trade-off between speed and maneuverability was non-linear. Phenotypes possessing trade-off functions for which maneuverability was only compromised at high speeds exhibited lower optimal speeds. Phenotypes that exhibited greater increases in maneuverability for any decrease in speed were more likely to have broader ranges of performance, meaning that individuals could attain their maximum performance across a broader range of speeds. We also found that there was a differential response of the subject's learning to these different components of locomotion. With increased experience through repeated trials
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
The Risk-Return Trade-Off in Human Capital Investment

DEFF Research Database (Denmark)

Christiansen, Charlotte; Joensen, Juanna Schrøter; Nielsen, Helena Skyt

In this paper we analyze investments in human capital assets in a way which is standard for financial assets, but not (yet) for human capital assets. We study mean-variance plots of human capital assets. We compare the properties of human capital returns using a performance measure and by sing...... tests for mean-variance spanning. A risk-return trade-off is revealed, hich is not only related to the length of education but also to the type of education. We identify a range of educations that are efficient in terms of investment goods, and a range of educations that are inefficient, and may...
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.
Morphological differences between habitats are associated with physiological and behavioural trade-offs in stickleback (Gasterosteus aculeatus).

Science.gov (United States)

Seebacher, Frank; Webster, Mike M; James, Rob S; Tallis, Jason; Ward, Ashley J W

2016-06-01

Local specialization can be advantageous for individuals and may increase the resilience of the species to environmental change. However, there may be trade-offs between morphological responses and physiological performance and behaviour. Our aim was to test whether habitat-specific morphology of stickleback (Gasterosteus aculeatus) interacts with physiological performance and behaviour at different salinities. We rejected the hypothesis that deeper body shape of fish from habitats with high predation pressure led to decreases in locomotor performance. However, there was a trade-off between deeper body shape and muscle quality. Muscle of deeper-bodied fish produced less force than that of shallow-bodied saltmarsh fish. Nonetheless, saltmarsh fish had lower swimming performance, presumably because of lower muscle mass overall coupled with smaller caudal peduncles and larger heads. Saltmarsh fish performed better in saline water (20 ppt) relative to freshwater and relative to fish from freshwater habitats. However, exposure to salinity affected shoaling behaviour of fish from all habitats and shoals moved faster and closer together compared with freshwater. We show that habitat modification can alter phenotypes of native species, but local morphological specialization is associated with trade-offs that may reduce its benefits.
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...
Mate choice trade-offs and women's preference for physically attractive men.

Science.gov (United States)

Waynforth, D

2001-09-01

Researchers studying human sexuality have repeatedly concluded that men place more emphasis on the physical attractiveness of potential mates than women do, particularly in long-term sexual relationships. Evolutionary theorists have suggested that this is the case because male mate value (the total value of the characteristics that an individual possesses in terms of the potential contribution to his or her mate's reproductive success) is better predicted by social status and economic resources, whereas women's mate value hinges on signals conveyed by their physical appearance. This pattern may imply that women trade off attractiveness for resources in mate choice. Here I test whether a trade-off between resources and attractiveness seems to be occurring in the mate choice decisions of women in the United States. In addition, the possibility that the risk of mate desertion drives women to choose less attractive men as long-term mates is tested. The results were that women rated physically attractive men as more likely to cheat or desert a long-term relationship, whereas men did not consider attractive women to be more likely to cheat. However, women showed no aversion to the idea of forming long-term relationships with attractive men. Evidence for a trade-off between resources and attractiveness was found for women, who traded off attractiveness, but not other traits, for resources. The potential meaning of these findings, as well as how they relate to broader issues in the study of sex differences in the evolution of human mate choice for physical traits, is discussed.
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.
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...
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.
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.
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.
Trading off Aircraft Fuel Burn and NO x Emissions for Optimal Climate Policy.

Science.gov (United States)

Freeman, Sarah; Lee, David S; Lim, Ling L; Skowron, Agnieszka; De León, Ruben Rodriguez

2018-03-06

Aviation emits pollutants that affect the climate, including CO 2 and NO x , NO x indirectly so, through the formation of tropospheric ozone and reduction of ambient methane. To improve the fuel performance of engines, combustor temperatures and pressures often increase, increasing NO x emissions. Conversely, combustor modifications to reduce NO x may increase CO 2 . Hence, a technology trade-off exists, which also translates to a trade-off between short-lived climate forcers and a long-lived greenhouse gas, CO 2 . Moreover, the NO x -O 3 -CH 4 system responds in a nonlinear manner, according to both aviation emissions and background NO x . A simple climate model was modified to incorporate nonlinearities parametrized from a complex chemistry model. Case studies showed that for a scenario of a 20% reduction in NO x emissions the consequential CO 2 penalty of 2% actually increased the total radiative forcing (RF). For a 2% fuel penalty, NO x emissions needed to be reduced by >43% to realize an overall benefit. Conversely, to ensure that the fuel penalty for a 20% NO x emission reduction did not increase overall forcing, a 0.5% increase in CO 2 was found to be the "break even" point. The time scales of the climate effects of NO x and CO 2 are quite different, necessitating careful analysis of proposed emissions trade-offs.
The role of dynamic trade-offs in creating safety—A qualitative study of handover across care boundaries in emergency care

International Nuclear Information System (INIS)

Sujan, Mark; Spurgeon, Peter; Cooke, Matthew

2015-01-01

The paper aims to demonstrate how the study of everyday clinical work can contribute novel insights into a common and stubborn patient safety problem—the vulnerabilities of handover across care boundaries in emergency care. Based on a dialectical interpretation of the empirical evidence gathered in five National Health Service organisations, the paper argues that performance variability is an essential component in the delivery of safe care, as practitioners translate tensions they encounter in their everyday work into safe practices through dynamic trade-offs based on their experience and the requirements of the specific situation. The findings may shed new light on the vulnerabilities of the handover process, and they might help explain why improvements to handover have remained largely elusive and what type of future recommendations may be appropriate for improving patient safety. - Highlights: • Qualitative study of emergency care handover across boundaries. • Description of tensions in everyday clinical work. • Exploration of the role of dynamic trade-offs. • Application of resilience engineering thinking to handover
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

"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...
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.
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....
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.
Evaluating the impact of the alcohol act on off-trade alcohol sales: a natural experiment in Scotland.

Science.gov (United States)

Robinson, Mark; Geue, Claudia; Lewsey, James; Mackay, Daniel; McCartney, Gerry; Curnock, Esther; Beeston, Clare

2014-12-01

A ban on multi-buy discounts of off-trade alcohol was introduced as part of the Alcohol Act in Scotland in October 2011. The aim of this study was to assess the impact of this legislation on alcohol sales, which provide the best indicator of population consumption. Interrupted time-series regression was used to assess the impact of the Alcohol Act on alcohol sales among off-trade retailers in Scotland. Models accounted for underlying seasonal and secular trends and were adjusted for disposable income, alcohol prices and substitution effects. Data for off-trade retailers in England and Wales combined (EW) provided a control group. Weekly data on the volume of pure alcohol sold by off-trade retailers in Scotland and EW between January 2009 and September 2012. The introduction of the legislation was associated with a 2.6% (95% CI = -5.3 to 0.2%, P = 0.07) decrease in off-trade alcohol sales in Scotland, but not in EW (-0.5%, 95% CI = -4.6 to 3.9%, P = 0.83). A statistically significant reduction was observed in Scotland when EW sales were adjusted for in the analysis (-1.7%, 95% CI = -3.1 to -0.3%, P = 0.02). The decline in Scotland was driven by reduced off-trade sales of wine (-4.0%, 95% CI = -5.4 to -2.6%, P types in Scotland, or in sales of any drink type in EW. The introduction of the Alcohol Act in Scotland in 2011 was associated with a decrease in total off-trade alcohol sales in Scotland, largely driven by reduced off-trade wine sales. © 2014 The Authors. Addiction published by John Wiley & Sons Ltd on behalf of Society for the Study of Addiction.
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
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)
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.
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.
Sex-specific trade-offs and compensatory mechanisms: bite force and sprint speed pose conflicting demands on the design of geckos (Hemidactylus frenatus).

Science.gov (United States)

Cameron, S F; Wynn, M L; Wilson, R S

2013-10-15

One of the more intuitive viability costs that can result from the possession of exaggerated sexually selected traits is increased predation pressure as a result of reduced locomotor capacity. Despite mixed empirical support for such locomotor costs, recent studies suggest that such costs may be masked by compensatory traits that effectively offset any detrimental effects. In this study, we provide a comprehensive assessment of the locomotor costs associated with improved male-male competitive ability by simultaneously testing for locomotor trade-offs and potential compensatory mechanisms in territorial male and non-territorial female geckos. Fighting capacity and escape performance of male Asian house geckos (Hemidactylus frenatus) are likely to pose conflicting demands on the optimum phenotype for each task. Highly territorial and aggressive males may require greater investment in head size/strength but such an enhancement may affect overall escape performance. Among male geckos, we found that greater biting capacity because of larger head size was associated with reduced sprint performance; this trade-off was further exacerbated when sprinting on an incline. Females, however, showed no evidence of this trade-off on either flat or inclined surfaces. The sex specificity of this trade-off suggests that the sexes differ in their optimal strategies for dealing with the conflicting requirements of bite force and sprint speed. Unlike males, female H. frenatus had a positive association between hind-limb length and head size, suggesting that they have utilised a compensatory mechanism to alleviate the possible locomotor costs of larger head sizes. It appears that there is greater selection on traits that improve fighting ability (bite force) for males, but it is viability traits (sprint speed) that appear to be of greater importance for females. Our results emphasise that only by examining both functional trade-offs and potential compensatory mechanisms is it possible
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 ...
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.
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
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.
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
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).
Remarks on manipulator classification and reversibility - deflection - backlash - inertia - balance and friction trade off

International Nuclear Information System (INIS)

Vertut, Jean.

1976-01-01

In a previous work the author proposed a time efficiency quotient based on time to perform a task for a man controlling a manipulator (RO MAN SY 73). This quotient is also a global evaluation of a man-manipulator system, and can be extended to teaching programmed manipulators. Classification based on this quotient emphasizes the importance of force feed-back to the operator, and enables to project the same concept to computer control. This paper concentrates on characteristics reflecting directly to the mechanics of the arm, to the actuators and to the control. They need delicate trade off: reversibility is key to force feed-back, deflection reflects on arm dynamics (oscillation) and precision, backlash allows lower friction but limits servo performances, inertia is high when limited deflection is required, friction is limiting the man in the loop performances, force transducers can compensate irreversibility and/or friction but lead to control sophistication. These trade offs are developed, and some proposed constants are given for force feed-back manipulators
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
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.
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

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

Directory of Open Access Journals (Sweden)

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.
Trade-off study on the power capacity of a prototype SFR in Korea

International Nuclear Information System (INIS)

Baek, M. H.; Kim, S. J.; Yoo, J.; Bae, I. H.

2012-01-01

The major roles of a prototype SFR are to provide irradiation test capability for the fuel and structure materials, and to obtain operational experiences of systems. Due to a compromise between the irradiation capability and construction costs, the power level should be properly determined. In this paper, a trade-off study on the power level of the prototype SFR was performed from a neutronics viewpoint. To select candidate cores, the parametric study of pin diameters was estimated using 20 wt.% uranium fuel. The candidate cores of different power levels, 125 MWt, 250 MWt, 400 MWt, and 500 MWt, were compared with the 1500 MWt reference core. The resulting core performance and economic efficiency indices became insensitive to the power at about 400-500 MWt and sharply deteriorated at about 125-250 MWt with decreasing core sizes. Fuel management scheme, TRU core performance comparing with uranium core, and sodium void reactivity were also evaluated with increasing power levels. It is found that increasing the number of batches showed higher burnup performance and economic efficiency. However, increasing the cycle length showed the trends in lower economic efficiency. Irradiation performance of TRU and enriched TRU cores was improved about 20 % and 50 %, respectively. The maximum sodium void reactivity of 5.2$ was confirmed less than the design limit of 7.5$. As a result, the power capacity of the prototype SFR should not be less than 250 MWt and would be appropriate at ∼ 500 MWt considering the performance and economic efficiency. (authors)
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.
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...
Sulfur and octane trade off in FCC naphta conventional hydrotreating

Energy Technology Data Exchange (ETDEWEB)

Badra, C. [INTEVEP S.A. Research and Technological Support Center of Petroleos de Venzuela, Caracas (Venezuela). Dept. de Refinacion; Perez, J.A. [INTEVEP S.A. Research and Technological Support Center of Petroleos de Venzuela, Caracas (Venezuela). Dept. de Refinacion; Salazar, J.A. [INTEVEP S.A. Research and Technological Support Center of Petroleos de Venzuela, Caracas (Venezuela). Dept. de Refinacion; Cabrera, L. [INTEVEP S.A. Research and Technological Support Center of Petroleos de Venzuela, Caracas (Venezuela). Dept. de Refinacion; Gracia, W. [INTEVEP S.A. Research and Technological Support Center of Petroleos de Venzuela, Caracas (Venezuela). Dept. de Refinacion

1997-06-01

A model to predict the change of octane numbers expected in an FCC naphtha hydrotreating process as a function of the hydroprocessing severity (degree of sulfur removal) and the type of naphtha (expressed as the sulfur content and bromine number in the feedstock) is presented. When considering hydrotreating as an option for processing their catalytic naphthas, refiners search for the proper balance between the desired reduction of sulfur and olefins and the resulting undesired reduction of octane (RON and MON). In doing so, refiners should study the possibility of performing the hydrotreating at mild severities and/or the possibility of fractionating FCC naphthas to just treat a specific cut. This paper provides simple tools to study and analyze these study cases and to assess the sulfur-octane trade offs. (orig.)
Trade-off between growth and immune function : a meta-analysis of selection experiments

NARCIS (Netherlands)

van der Most, Peter; de Jong, Berber; Parmentier, Henk K.; Verhulst, Simon

P>1. Evidence suggests that developing and maintaining an effective immune system may be costly and that an organism has to make a trade-off between immune function and other fitness-enhancing traits. To test for a trade-off between growth and immune function we carried out a meta-analysis of data
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.
Experimental evolution reveals trade-offs between mating and immunity.

Science.gov (United States)

McNamara, Kathryn B; Wedell, Nina; Simmons, Leigh W

2013-08-23

Immune system maintenance and upregulation is costly. Sexual selection intensity, which increases male investment into reproductive traits, is expected to create trade-offs with immune function. We assayed phenoloxidase (PO) and lytic activity of individuals from populations of the Indian meal moth, Plodia interpunctella, which had been evolving under different intensities of sexual selection. We found significant divergence among populations, with males from female-biased populations having lower PO activity than males from balanced sex ratio or male-biased populations. There was no divergence in anti-bacterial lytic activity. Our data suggest that it is the increased male mating demands in female-biased populations that trades-off against immunity, and not the increased investment in sperm transfer per mating that characterizes male-biased populations.
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
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
Information/disturbance trade-off in single and sequential measurements on a qudit signal

Energy Technology Data Exchange (ETDEWEB)

Genoni, Marco G; Paris, Matteo G A [Dipartimento di Fisica, Universita degli studi di Milano (Italy)

2007-05-15

We address the trade-off between information gain and state disturbance in measurement performed on qudit systems and devise a class of optimal measurement schemes that saturate the ultimate bound imposed by quantum mechanics to estimation and transmission fidelities. The schemes are minimal, i.e. they involve a single additional probe qudit, and optimal, i.e. they provide the maximum amount of information compatible with a given level of disturbance. The performances of optimal single-user schemes in extracting information by sequential measurements in a N-user transmission line are also investigated, and the optimality is analyzed by explicit evaluation of fidelities. We found that the estimation fidelity does not depend on the number of users, neither for single-measure inference nor for collective one, whereas the transmission fidelity decreases with N. The resulting trade-off is no longer optimal and degrades with increasing N. We found that optimality can be restored by an effective preparation of the probe states and present explicitly calculations for the 2-user case.
Trade-off analysis of high-aspect-ratio-cooling-channels for rocket engines

International Nuclear Information System (INIS)

Pizzarelli, Marco; Nasuti, Francesco; Onofri, Marcello

2013-01-01

Highlights: • Aspect ratio has a significant effect on cooling efficiency and hydraulic losses. • Minimizing power loss is of paramount importance in liquid rocket engine cooling. • A suitable quasi-2D model is used to get fast cooling system analysis. • Trade-off with assigned weight, temperature, and channel height or wall thickness. • Aspect ratio is found that minimizes power loss in the cooling circuit. -- Abstract: High performance liquid rocket engines are often characterized by rectangular cooling channels with high aspect ratio (channel height-to-width ratio) because of their proven superior cooling efficiency with respect to a conventional design. However, the identification of the optimum aspect ratio is not a trivial task. In the present study a trade-off analysis is performed on a cooling channel system that can be of interest for rocket engines. This analysis requires multiple cooling channel flow calculations and thus cannot be efficiently performed by CFD solvers. Therefore, a proper numerical approach, referred to as quasi-2D model, is used to have fast and accurate predictions of cooling system properties. This approach relies on its capability of describing the thermal stratification that occurs in the coolant and in the wall structure, as well as the coolant warming and pressure drop along the channel length. Validation of the model is carried out by comparison with solutions obtained with a validated CFD solver. Results of the analysis show the existence of an optimum channel aspect ratio that minimizes the requested pump power needed to overcome losses in the cooling circuit
Anthrax Sampling and Decontamination: Technology Trade-Offs

Energy Technology Data Exchange (ETDEWEB)

Price, Phillip N.; Hamachi, Kristina; McWilliams, Jennifer; Sohn, Michael D.

2008-09-12

The goal of this project was to answer the following questions concerning response to a future anthrax release (or suspected release) in a building: 1. Based on past experience, what rules of thumb can be determined concerning: (a) the amount of sampling that may be needed to determine the extent of contamination within a given building; (b) what portions of a building should be sampled; (c) the cost per square foot to decontaminate a given type of building using a given method; (d) the time required to prepare for, and perform, decontamination; (e) the effectiveness of a given decontamination method in a given type of building? 2. Based on past experience, what resources will be spent on evaluating the extent of contamination, performing decontamination, and assessing the effectiveness of the decontamination in abuilding of a given type and size? 3. What are the trade-offs between cost, time, and effectiveness for the various sampling plans, sampling methods, and decontamination methods that have been used in the past?
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.
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 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 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.
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.
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.
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
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
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.
Off-Site Prefabrication: What Does it Require from the Trade Contractor?

DEFF Research Database (Denmark)

Bekdik, Baris; Hall, Daniel; Aslesen, Sigmund

2016-01-01

The purpose of the paper is to show what is required to industrialize a building process from the standpoint of the trade contractor. Rationalization of building processes has, over the years, caught the attention of numerous IGLC papers. Although significant contributions have been made to further...... understand and improve existing construction processes, relatively few contributions have focused on the opportunities for industrialization from the trade contractor’s perspective. This paper uses an in-depth case study to address the deployment strategy for off-site fabrication techniques and processes...... at only one case study, the conclusions are limited in generalizability to other prefabrication operations. However, it represents an important in-depth case from the trade contractors’ perspective and will contribute to the growing body of research focused on industrialization and prefabrication in lean...
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.
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.
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.
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.
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…
A Typology Framework for Trade-Offs in Development and Disaster Risk Reduction: A Case Study of Typhoon Haiyan Recovery in Tacloban, Philippines

Directory of Open Access Journals (Sweden)

Heidi Tuhkanen

2018-06-01

Full Text Available Development and disaster risk are deeply linked. Disasters reverse development gains; development initiatives influence the risk, vulnerability, and exposure of people, assets, and environments to disasters. Hence, knowledge of key dimensions of the potential trade-offs between development and disaster risk reduction (DRR may inform decision-making processes, goals, and initiatives in ways that have potential to address unsustainable development practices that are commonplace in countries of all economic levels. This paper presents, explores, and tests a conceptual framework for analysing the trade-offs that underpin this relationship as evidenced through policy goals, initiatives, and decision-making processes. We categorise key dimensions of relevant trade-offs into five specific dimensions: (i The aggregation of development and DRR gains and losses, (ii risk prioritisation when seeking to reduce multiple risks, (iii the equity of decision-making processes and outcomes, (iv the balancing of near- and long-term goals, and (v the distribution of power and participation. By framing key questions related to each trade-off dimension, we test the framework in the context of a major disaster recovery process in Tacloban, the Philippines, following Typhoon Haiyan (Yolanda in November 2013. We consider how decision-making trade-offs can be made more visible and useful in the pursuit of transformative change in development and DRR.
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.
An alternative test of the trade-off theory of capital structure

Directory of Open Access Journals (Sweden)

Giorgio Canarella

2014-12-01

Full Text Available The purpose of this paper is to investigate the stochastic behavior of corporate debt ratios utilizing a balanced panel of 2,556 publicly traded U.S. firms during the period 1997-2010. We partition the panel into ten economic sectors and perform panel unit root tests on each sector employing book value and market value measures of debt ratio. First-generation panel unit root tests provide consistent evidence that debt ratios are mean reverting, which supports the trade-off theory. However, these tests rely on the assumption that the debt ratios are cross-sectionally independent, but tests of cross-sectional independence fail to uphold this assumption. Thus, utilizing a second-generation panel unit root test that controls for cross-sectional dependence, we uncover evidence showing that debt ratios are not mean reverting, which contradicts the trade-off hypothesis. We find that the recent macroeconomic developments triggered by the financial crisis and the Great Recession have considerable explanatory power over the dynamics of the debt ratios. In fact, when we exclude the years of the recent global financial crisis, the unit root hypothesis is rejected in one half of the sectors. We interpret these results as indicative that the recent global events may have produced in these sectors a structural change in the underlying data generation process (DGP. Overall, then, we find mixed evidence on the stationarity of debt ratios.
Ecosystem service trade-offs, perceived drivers, and sustainability in contrasting agroecosystems in central Mexico

Directory of Open Access Journals (Sweden)

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

Science.gov (United States)

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

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.
Pulsed activation analyses of the ITER blanket design options considered in the blanket trade-off study

International Nuclear Information System (INIS)

Wang, Q.; Henderson, D.L.

1995-01-01

Pulsed activation calculations have been performed on two blanket options considered as part of the ITER home team blanket trade-off study. The objective was to compare the activity, afterheat and waste disposal rating (WDR) results of a composite blanket-shield design for the continuous operation approximation to a pulsed operation case to determine whether the differences are at most the duty factor as predicted by the two nuclide chain model. Up to a cooling period of 100 years, the pulsed activity and afterheat values were below the continuous oepration results and well within (except for one afterheat value) the maximum deviation predicted by the two nuclide chain model. No differences in the WDR values were noted as they are, to a large extent, based on long-lived nuclides which are insensitive to short-term changes in the operation history. (orig.)
Optimal power and performance trade-offs for dynamic voltage scaling in power management based wireless sensor node

Directory of Open Access Journals (Sweden)

Anuradha Pughat

2016-09-01

Full Text Available Dynamic voltage scaling contributes to a significant amount of power saving, especially in the energy constrained wireless sensor networks (WSNs. Existing dynamic voltage scaling techniques make the system slower and ignore the event miss rate. This results in degradation of the system performance when there is non-stationary workload at input. The overhead due to transition between voltage level and discrete voltage levels are also the limitations of available dynamic voltage scaling (DVS techniques at sensor node (SN. This paper proposes a workload dependent DVS based MSP430 controller model used for SN. An online gradient estimation technique has been used to optimize power and performance trade-offs. The analytical results are validated with the simulation results obtained using simulation tool “SimEvents” and compared with the available AT9OS8535 controller. Based on the stochastic workload, the controller's input voltage, operational frequency, utilization, and average wait time of events are obtained.
Trade-off between early emergence and herbivore susceptibility mediates exotic success in an experimental California plant community.

Science.gov (United States)

Waterton, Joseph; Cleland, Elsa E

2016-12-01

Ecological trade-offs are fundamental to theory in community ecology; critical for understanding species coexistence in diverse plant communities, as well as the evolution of diverse life-history strategies. Invasions by exotic species can provide insights into the importance of trade-offs in community assembly, because the ecological strategies of invading species often differ from those present in the native species pool. Exotic annual species have invaded many Mediterranean-climate areas around the globe, and often germinate and emerge earlier in the growing season than native species. Early-season growth can enable exotic annual species to preempt space and resources, competitively suppressing later-emerging native species; however, early-emerging individuals may also be more apparent to herbivores. This suggests a potential trade-off between seasonal phenology and susceptibility to herbivory. To evaluate this hypothesis, we monitored the emergence and growth of 12 focal species (six each native and exotic) in monoculture and polyculture, while experimentally excluding generalist herbivores both early and later in the growing season. Consistent with past studies, the exotic species emerged earlier than native species. Regardless of species origin, earlier-emerging species achieved greater biomass by the end of the experiment, but were more negatively impacted by herbivory, particularly in the early part of the growing season. This greater impact of early-season herbivory on early-active species led to a reduction in the competitive advantage of exotic species growing in polyculture, and improved the performance of later-emerging natives. Such a trade-off between early growth and susceptibility to herbivores could be an important force in community assembly in seasonal herbaceous-dominated ecosystems. These results also show how herbivore exclusion favors early-active exotic species in this system, with important implications for management in many areas invaded
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. ...
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.
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
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.
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...
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.
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.
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...
Analyzing Reliability and Performance Trade-Offs of HLS-Based Designs in SRAM-Based FPGAs Under Soft Errors

Science.gov (United States)

Tambara, Lucas Antunes; Tonfat, Jorge; Santos, André; Kastensmidt, Fernanda Lima; Medina, Nilberto H.; Added, Nemitala; Aguiar, Vitor A. P.; Aguirre, Fernando; Silveira, Marcilei A. G.

2017-02-01

The increasing system complexity of FPGA-based hardware designs and shortening of time-to-market have motivated the adoption of new designing methodologies focused on addressing the current need for high-performance circuits. High-Level Synthesis (HLS) tools can generate Register Transfer Level (RTL) designs from high-level software programming languages. These tools have evolved significantly in recent years, providing optimized RTL designs, which can serve the needs of safety-critical applications that require both high performance and high reliability levels. However, a reliability evaluation of HLS-based designs under soft errors has not yet been presented. In this work, the trade-offs of different HLS-based designs in terms of reliability, resource utilization, and performance are investigated by analyzing their behavior under soft errors and comparing them to a standard processor-based implementation in an SRAM-based FPGA. Results obtained from fault injection campaigns and radiation experiments show that it is possible to increase the performance of a processor-based system up to 5,000 times by changing its architecture with a small impact in the cross section (increasing up to 8 times), and still increasing the Mean Workload Between Failures (MWBF) of the system.
Attention induced neural response trade-off in retinotopic cortex under load.

Science.gov (United States)

Torralbo, Ana; Kelley, Todd A; Rees, Geraint; Lavie, Nilli

2016-09-14

The effects of perceptual load on visual cortex response to distractors are well established and various phenomena of 'inattentional blindness' associated with elimination of visual cortex response to unattended distractors, have been documented in tasks of high load. Here we tested an account for these effects in terms of a load-induced trade-off between target and distractor processing in retinotopic visual cortex. Participants were scanned using fMRI while performing a visual-search task and ignoring distractor checkerboards in the periphery. Retinotopic responses to target and distractors were assessed as a function of search load (comparing search set-sizes two, three and five). We found that increased load not only increased activity in frontoparietal network, but also had opposite effects on retinotopic responses to target and distractors. Target-related signals in areas V2-V3 linearly increased, while distractor response linearly decreased, with increased load. Critically, the slopes were equivalent for both load functions, thus demonstrating resource trade-off. Load effects were also found in displays with the same item number in the distractor hemisphere across different set sizes, thus ruling out local intrahemispheric interactions as the cause. Our findings provide new evidence for load theory proposals of attention resource sharing between target and distractor leading to inattentional blindness.
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.
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.
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.
Trade-offs in osmoregulation and parallel shifts in molecular function follow ecological transitions to freshwater in the Alewife

Science.gov (United States)

Velotta, Jonathan P.; McCormick, Stephen; Schultz, Eric T.

2015-01-01

Adaptation to freshwater may be expected to reduce performance in seawater because these environments represent opposing selective regimes. We tested for such a trade-off in populations of the Alewife (Alosa pseudoharengus). Alewives are ancestrally anadromous, and multiple populations have been independently restricted to freshwater (landlocked). We conducted salinity challenge experiments, whereby juvenile Alewives from one anadromous and multiple landlocked populations were exposed to freshwater and seawater on acute and acclimation timescales. In response to acute salinity challenge trials, independently derived landlocked populations varied in the degree to which seawater tolerance has been lost. In laboratory-acclimation experiments, landlocked Alewives exhibited improved freshwater tolerance, which was correlated with reductions in seawater tolerance and hypo-osmotic balance, suggesting that trade-offs in osmoregulation may be associated with local adaptation to freshwater. We detected differentiation between life-history forms in the expression of an ion-uptake gene (NHE3), and in gill Na+/K+-ATPase activity. Trade-offs in osmoregulation, therefore, may be mediated by differentiation in ion-uptake and salt-secreting pathways.
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

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.
Robust broadband nanopositioning: fundamental trade-offs, analysis, and design in a two-degree-of-freedom control framework

International Nuclear Information System (INIS)

Lee, Chibum; Salapaka, Srinivasa M

2009-01-01

This paper studies and analyses fundamental trade-offs between positioning resolution, tracking bandwidth, and robustness to modeling uncertainties in two-degree-of-freedom (2DOF) control designs for nanopositioning systems. The analysis of these systems is done in optimal control setting with various architectural constraints imposed on the 2DOF framework. In terms of these trade-offs, our analysis shows that the primary role of feedback is providing robustness to the closed-loop device whereas the feedforward component is mainly effective in overcoming fundamental algebraic constraints that limit the feedback-only designs. This paper presents (1) an optimal prefilter model matching design for a system with an existing feedback controller, (2) a simultaneous feedforward and feedback control design in an optimal mixed sensitivity framework, and (3) a 2DOF optimal robust model matching design. The experimental results on applying these controllers show a significant improvement, as high as 330% increase in bandwidth for similar robustness and resolution over optimal feedback-only designs. Other performance objectives can be improved similarly. We demonstrate that the 2DOF freedom design achieves performance specifications that are analytically impossible for feedback-only designs.
A Multi-Objective Trade-Off Model in Sustainable Construction Projects

Directory of Open Access Journals (Sweden)

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
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.
DO TANZANIAN COMPANIES PRACTICE PECKING ORDER THEORY, AGENCY COST THEORY OR TRADE-OFF THEORY? AN EMPIRICAL STUDY IN TANZANIAN LISTED COMPANIES

Directory of Open Access Journals (Sweden)

Ntogwa Ng'habi Bundala

2012-01-01

Full Text Available The empirical study was focused predominantly on validity tests of the three theories on capital structures, the static trade-off theory, the pecking order theory (information asymmetry theory, and agency cost theory in the Tanzanian context. The study used secondary data from eight of the non-financial companies listed in Dar Es Salaam Stock Exchange (DSE from 2006-2012. The study used descriptive (quantitative approach to test the practicality of the theories in Tanzania. The multiple regressions model used to test the theoretical relationship between the financial leverage and characteristics of the company. The research found that there is no strong evidence for validation of static trade off theory, little support of pecking order theory, but the agency cost theory is confirmed to be valid and practiced in Tanzania. It recommended that Tanzanian companies should be adhering to the determinants of the capital structure in the Tanzanian context found by this study.
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
Adaptive trade-offs in juvenile salmonid metabolism associated with habitat partitioning between coho salmon and steelhead trout in coastal streams.

Science.gov (United States)

Van Leeuwen, Travis E; Rosenfeld, Jordan S; Richards, Jeffrey G

2011-09-01

1. Adaptive trade-offs are fundamental to the evolution of diversity and the coexistence of similar taxa and occur when complimentary combinations of traits maximize efficiency of resource exploitation or survival at different points on environmental gradients. 2. Standard metabolic rate (SMR) is a key physiological trait that reflects adaptations to baseline metabolic performance, whereas active metabolism reflects adaptations to variable metabolic output associated with performance related to foraging, predator avoidance, aggressive interactions or migratory movements. Benefits of high SMR and active metabolism may change along a resource (productivity) gradient, indicating that a trade-off exists among active metabolism, resting metabolism and energy intake. 3. We measured and compared SMR, maximal metabolic rate (MMR), aerobic scope (AS), swim performance (UCrit) and growth of juvenile hatchery and wild steelhead and coho salmon held on high- and low-food rations in order to better understand the potential significance of variation in SMR to growth, differentiation between species, and patterns of habitat use along a productivity gradient. 4. We found that differences in SMR, MMR, AS, swim performance and growth rate between steelhead trout and coho salmon were reduced in hatchery-reared fish compared with wild fish. Wild steelhead had a higher MMR, AS, swim performance and growth rate than wild coho, but adaptations between species do not appear to involve differences in SMR or to trade-off increased growth rate against lower swim performance, as commonly observed for high-growth strains. Instead, we hypothesize that wild steelhead may be trading off higher growth rate for lower food consumption efficiency, similar to strategies adopted by anadromous vs. resident brook trout and Atlantic salmon vs. brook trout. This highlights potential differences in food consumption and digestion strategies as cryptic adaptations ecologically differentiating salmonid species
Evaluation of reconstruction techniques in regional cerebral blood flow SPECT using trade-off plots: a Monte Carlo study.

Science.gov (United States)

Olsson, Anna; Arlig, Asa; Carlsson, Gudrun Alm; Gustafsson, Agnetha

2007-09-01

The image quality of single photon emission computed tomography (SPECT) depends on the reconstruction algorithm used. The purpose of the present study was to evaluate parameters in ordered subset expectation maximization (OSEM) and to compare systematically with filtered back-projection (FBP) for reconstruction of regional cerebral blood flow (rCBF) SPECT, incorporating attenuation and scatter correction. The evaluation was based on the trade-off between contrast recovery and statistical noise using different sizes of subsets, number of iterations and filter parameters. Monte Carlo simulated SPECT studies of a digital human brain phantom were used. The contrast recovery was calculated as measured contrast divided by true contrast. Statistical noise in the reconstructed images was calculated as the coefficient of variation in pixel values. A constant contrast level was reached above 195 equivalent maximum likelihood expectation maximization iterations. The choice of subset size was not crucial as long as there were > or = 2 projections per subset. The OSEM reconstruction was found to give 5-14% higher contrast recovery than FBP for all clinically relevant noise levels in rCBF SPECT. The Butterworth filter, power 6, achieved the highest stable contrast recovery level at all clinically relevant noise levels. The cut-off frequency should be chosen according to the noise level accepted in the image. Trade-off plots are shown to be a practical way of deciding the number of iterations and subset size for the OSEM reconstruction and can be used for other examination types in nuclear medicine.
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.
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.
A study of Trade-off between Opportunistic Resource Allocation and Interference Alignment in Femtocell Scenarios

DEFF Research Database (Denmark)

Lertwiram, Namzilp; Popovski, Petar; Sakaguchi, Kei

2012-01-01

One of the main problems in wireless heterogeneous networks is interference between macro- and femto-cells. Using Orthogonal Frequency-Division Multiple Access (OFDMA) to create multiple frequency orthogonal sub-channels, this interference can be completely avoided if each sub-channel is exclusiv...... of the communication resources. In this letter we investigate the interactions and the trade-offs between these two strategies....
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.
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...
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.
Cyber-Physical Trade-Offs in Distributed Detection Networks

International Nuclear Information System (INIS)

Rao, Nageswara S.; Yao, David K.Y.; Chin, J.C.; Ma, Chris Y.T.; Madan, Rabinder

2010-01-01

We consider a network of sensors that measure the scalar intensity due to the background or a source combined with background, inside a two-dimensional monitoring area. The sensor measurements may be random due to the underlying nature of the source and background or due to sensor errors or both. The detection problem is to infer the presence of a source of unknown intensity and location based on sensor measurements. In the conventional approach, detection decisions are made at the individual sensors, which are then combined at the fusion center, for example using the majority rule. With increased communication and computation costs, we show that a more complex fusion algorithm based on measurements achieves better detection performance under smooth and non-smooth source intensity functions, Lipschitz conditions on probability ratios and a minimum packing number for the state-space. We show that these conditions for trade-offs between the cyber costs and physical detection performance are applicable for two detection problems: (i) point radiation sources amidst background radiation, and (ii) sources and background with Gaussian distributions.
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.
Design principles and fundamental trade-offs in biomimetic light harvesting

International Nuclear Information System (INIS)

Sarovar, Mohan; Birgitta Whaley, K

2013-01-01

Recent developments in synthetic and supramolecular chemistry have created opportunities to design organic systems with tailored nanoscale structure for various technological applications. A key application area is the capture of light energy and its conversion into electrochemical or chemical forms for photovoltaic or sensing applications. In this work we consider cylindrical assemblies of chromophores that model structures produced by several supramolecular techniques. Our study is especially guided by the versatile structures produced by virus-templated assembly. We use a multi-objective optimization framework to determine design principles and limitations in light harvesting performance for such assemblies, both in the presence and absence of disorder. We identify a fundamental trade-off in cylindrical assemblies that is encountered when attempting to maximize both efficiency of energy transfer and absorption bandwidth. We also rationalize the optimal design strategies and provide explanations for why various structures provide optimal performance. Most importantly, we find that the optimal design strategies depend on the amount of energetic and structural disorder in the system. The aim of these studies is to develop a program of quantum-informed rational design for construction of organic assemblies that have the same degree of tailored nanoscale structure as biological photosynthetic light harvesting complexes, and consequently have the potential to reproduce their remarkable light harvesting performance. (paper)
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
No trade-off between learning speed and associative flexibility in bumblebees: a reversal learning test with multiple colonies.

Directory of Open Access Journals (Sweden)

Nigel E Raine

Full Text Available Potential trade-offs between learning speed and memory-related performance could be important factors in the evolution of learning. Here, we test whether rapid learning interferes with the acquisition of new information using a reversal learning paradigm. Bumblebees (Bombus terrestris were trained to associate yellow with a floral reward. Subsequently the association between colour and reward was reversed, meaning bees then had to learn to visit blue flowers. We demonstrate that individuals that were fast to learn yellow as a predictor of reward were also quick to reverse this association. Furthermore, overnight memory retention tests suggest that faster learning individuals are also better at retaining previously learned information. There is also an effect of relatedness: colonies whose workers were fast to learn the association between yellow and reward also reversed this association rapidly. These results are inconsistent with a trade-off between learning speed and the reversal of a previously made association. On the contrary, they suggest that differences in learning performance and cognitive (behavioural flexibility could reflect more general differences in colony learning ability. Hence, this study provides additional evidence to support the idea that rapid learning and behavioural flexibility have adaptive value.
Gastrointestinal helminths may affect host susceptibility to anthrax through seasonal immune trade-offs.

Science.gov (United States)

Cizauskas, Carrie A; Turner, Wendy C; Wagner, Bettina; Küsters, Martina; Vance, Russell E; Getz, Wayne M

2014-11-12

Most vertebrates experience coinfections, and many pathogen-pathogen interactions occur indirectly through the host immune system. These interactions are particularly strong in mixed micro-macroparasite infections because of immunomodulatory effects of helminth parasites. While these trade-offs have been examined extensively in laboratory animals, few studies have examined them in natural systems. Additionally, many wildlife pathogens fluctuate seasonally, at least partly due to seasonal host immune changes. We therefore examined seasonality of immune resource allocation, pathogen abundance and exposure, and interactions between infections and immunity in plains zebra (Equus quagga) in Etosha National Park (ENP), Namibia, a system with strongly seasonal patterns of gastrointestinal (GI) helminth infection intensity and concurrent anthrax outbreaks. Both pathogens are environmentally transmitted, and helminth seasonality is driven by environmental pressures on free living life stages. The reasons behind anthrax seasonality are currently not understood, though anthrax is less likely directly driven by environmental factors. We measured a complex, interacting set of variables and found evidence that GI helminth infection intensities, eosinophil counts, IgE and IgGb antibody titers, and possibly IL-4 cytokine signaling were increased in wetter seasons, and that ectoparasite infestations and possibly IFN-γ cytokine signaling were increased in drier seasons. Monocyte counts and anti-anthrax antibody titers were negatively associated with wet season eosinophilia, and monocytes were negatively correlated with IgGb and IgE titers. Taken together, this supports the hypothesis that ENP wet seasons are characterized by immune resource allocation toward Th-2 type responses, while Th1-type immunity may prevail in drier seasons, and that hosts may experience Th1-Th2 trade-offs. We found evidence that this Th2-type resource allocation is likely driven by GI parasite infections

Adaptive order search and tangent-weighted trade-off for motion estimation in H.264

Directory of Open Access Journals (Sweden)

Srinivas Bachu

2018-04-01

Full Text Available Motion estimation and compensation play a major role in video compression to reduce the temporal redundancies of the input videos. A variety of block search patterns have been developed for matching the blocks with reduced computational complexity, without affecting the visual quality. In this paper, block motion estimation is achieved through integrating the square as well as the hexagonal search patterns with adaptive order. The proposed algorithm is called, AOSH (Adaptive Order Square Hexagonal Search algorithm, and it finds the best matching block with a reduced number of search points. The searching function is formulated as a trade-off criterion here. Hence, the tangent-weighted function is newly developed to evaluate the matching point. The proposed AOSH search algorithm and the tangent-weighted trade-off criterion are effectively applied to the block estimation process to enhance the visual quality and the compression performance. The proposed method is validated using three videos namely, football, garden and tennis. The quantitative performance of the proposed method and the existing methods is analysed using the Structural SImilarity Index (SSIM and the Peak Signal to Noise Ratio (PSNR. The results prove that the proposed method offers good visual quality than the existing methods. Keywords: Block motion estimation, Square search, Hexagon search, H.264, Video coding
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)
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 ...
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
Importance Performance Analysis as a Trade Show Performance Evaluation and Benchmarking Tool

OpenAIRE

Tafesse, Wondwesen; Skallerud, Kåre; Korneliussen, Tor

2010-01-01

Author's accepted version (post-print). The purpose of this study is to introduce importance performance analysis as a trade show performance evaluation and benchmarking tool. Importance performance analysis considers exhibitors’ performance expectation and perceived performance in unison to evaluate and benchmark trade show performance. The present study uses data obtained from exhibitors of an international trade show to demonstrate how importance performance analysis can be used to eval...
Design trade study for a 4-meter off-axis primary mirror substrate and mount for the Habitable-zone Exoplanet Direct Imaging Mission

Science.gov (United States)

Arnold, William R.; Stahl, H. Philip

2017-09-01

An extensive trade study was conducted to evaluate primary mirror substrate design architectures for the HabEx mission baseline 4-meter off-axis telescope. The study's purpose is not to produce a final design, but rather to established a design methodology for matching the mirror's properties (mass and stiffness) with the mission's optical performance specifications (static dynamic wavefront error, WFE). The study systematically compares the effect of proven design elements (closed-back vs open-back vs partial-back; meniscus vs flat back vs shaped back; etc.), which can be implemented with proven space mirror materials (ULE and Zerodur), on static and dynamic WFE. Additionally, the study compares static and dynamic WFE of each substrate point design integrated onto three and six point mounts.
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
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.
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
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...
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.
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.
Residential moving intentions at highway locations: : The trade-off between nuisances and accessibility in the Netherlands

NARCIS (Netherlands)

Hamersma, Marije; Heinen, Eva; Tillema, Taede; Arts, Eric

2015-01-01

This study investigates how highway nuisances are traded off against accessibility gains and other residential characteristics in the moving intentions of people living near highways. It studies a potential mediating role for residential satisfaction and potential mitigating relationships with
Consumer adoption of personalised nutrition services from the perspective of a risk–benefit trade-off

NARCIS (Netherlands)

Berezowska, A.; Fischer, A.R.H.; Ronteltap, A.; Lans, van der I.A.; Trijp, van J.C.M.

2015-01-01

Through a Privacy Calculus (i.e. risk–benefit trade-off) lens, this study identifies factors that contribute to consumers’ adoption of personalised nutrition services. We argue that consumers’ intention to adopt personalised nutrition services is determined by perceptions of Privacy Risk,
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 ...
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.
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
Optimal control of LQG problem with an explicit trade-off between mean and variance

Science.gov (United States)

Qian, Fucai; Xie, Guo; Liu, Ding; Xie, Wenfang

2011-12-01

For discrete-time linear-quadratic Gaussian (LQG) control problems, a utility function on the expectation and the variance of the conventional performance index is considered. The utility function is viewed as an overall objective of the system and can perform the optimal trade-off between the mean and the variance of performance index. The nonlinear utility function is first converted into an auxiliary parameters optimisation problem about the expectation and the variance. Then an optimal closed-loop feedback controller for the nonseparable mean-variance minimisation problem is designed by nonlinear mathematical programming. Finally, simulation results are given to verify the algorithm's effectiveness obtained in this article.
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 ...
An experimental investigation of performance-emission trade off characteristics of a CI engine using hydrogen as dual fuel

International Nuclear Information System (INIS)

Deb, Madhujit; Paul, Abhishek; Debroy, Durbadal; Sastry, G.R.K.; Panua, Raj Sekhar; Bose, P.K.

2015-01-01

The investigation carried out in this research work concerns the effect of the addition of H 2 on performance and emission characteristics of a single cylinder, 4-stroke diesel engine. The tests were performed using diesel as a pilot fuel, with hydrogen addition at varying load condition using a Timed Manifold Injection (TMI) system has been developed using ECU (electronic control unit) with varying injection strategy to deliver hydrogen on to the intake manifold. The results showed a significant increase in BTE with appreciable decrease in BSEC of the engine when compared to conventional diesel-fueled operation. The emission of CO 2 and NOx was found to increase with enhancement of H 2 addition. The emission of UHC was found to be very high at low load conditions, but it enhanced as the load increased for all hydrogen injection while Soot emissions decreased. Thus, this paper provided a potential to investigate the effect of the addition of H 2 on the performance and emission characteristics of a diesel engine and how to get a best ratio of H 2 addition. The tradeoff study also consolidated the verity that Diesel–H 2 dual fuel operation was instrumental in resolving the high performance – low emission paradox. - Highlights: • Pure diesel and diesel–H 2 blends are tested. • Diesel–H 2 blends produced higher brake thermal efficiency than pure diesel in all part loads. • Diesel–H 2 blends reduced the energy consumption of the engine. • Diesel–H 2 blends simultaneously reduced Soot to some extent but increases N Ox and hydrocarbon emissions. • The performance-emission trade-off paradox has been studied using pure diesel and diesel–H 2 blends

Labour Market Programmes and the Equity-Efficiency Trade-off

DEFF Research Database (Denmark)

Filges, Trine; Kennes, John; Larsen, Birthe

This paper studies labour market policy in a society where differently gifted individuals can invest in training to further increase their labour market productivity and where the government seeks both effiency and equity. Frictions in the matching process create unemployment and differently...... skilled workers face different unemployment risks. We show that in such an environment, training programmes that are targeted to the unemployed complement passive transfers (UI benefits), unlike a general training subsidy. Combining passive subsidies with a training subsidy conditioned on the individual...... being unemployed (for a while) - the typical Active Labour Market Programme - implies a favorable trade-off between equity and efficiency which encourages high spending on training....
Labour Market Programmes and the Equity-Efficiency Trade-off

DEFF Research Database (Denmark)

Kennes, John; Larsen, Birthe; Tranæs, Torben

2005-01-01

This paper studies labour market policy in a society where differently gifted individuals can invest in training to further increase their labour market productivity and where the government seeks both effiency and equity. Frictions in the matching process create unemployment and differently...... skilled workers face different unemployment risks. We show that in such an environment, training programmes that are targeted to the unemployed complement passive transfers (UI benefits), unlike a general training subsidy. Combining passive subsidies with a training subsidy conditioned on the individual...... being unemployed (for a while) - the typical Active Labour Market Programme - implies a favorable trade-off between equity and efficiency which encourages high spending on training....
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...
Optimizing the number and locations of turbines in a wind farm addressing energy-noise trade-off: A hybrid approach

International Nuclear Information System (INIS)

Mittal, Prateek; Mitra, Kishalay; Kulkarni, Kedar

2017-01-01

Highlights: • Concurrent resolution of turbine number and locations during micro-siting. • Effect of noise on energy-noise multi-objective optimization is demonstrated. • A hybrid algorithm is proposed utilizing probabilistic and deterministic methods. • ∼24% improved performance is achieved over the benchmark case study. • ∼29% enhanced efficiency over real-binary genetic algorithm alone can be observed. - Abstract: Micro-siting is an optimal way of placing turbines inside a wind farm while considering various design objectives and constraints. Using a well-established Jensen wake model and ISO-9613-2 noise calculation, this study performs a wind farm layout optimization based on a multi-objective trade-off between minimization of the noise propagation and maximization of the energy generation. A novel hybrid methodology is developed which is a combination of probabilistic real-binary coded multi-objective evolutionary algorithm and a newly proposed deterministic gradient based non-dominated normalized normal constraint method. Based on the Inverted Generational Distance metric, the performance of the proposed method is found to be better than the conventional normalized normal constraint method or the concerned evolutionary method alone. Moreover, in contrast to the previous studies, the generated non-dominated front is capable of providing a trade-off between various alternative energy-noise solutions, along with an additional information about the corresponding turbine numbers and their optimal location coordinates. As a result, the decision maker can choose from different competing wind turbine layouts based on existing noise and other standard regulations.
Resolving the challenges in the international comparison of health systems: the must do's and the trade-offs.

Science.gov (United States)

Forde, Ian; Morgan, David; Klazinga, Niek S

2013-09-01

Countries are increasingly publishing health system performance statistics alongside those of their peers, to identify high performers and achieve a continuously improving health system. The aim of the paper is to identify, and discuss resolution of, some key methodological challenges, which arise when comparing health system performance. To illustrate the issues, we focus on two OECD flagship initiatives: the System of Health Accounts (SHA) and the Health Care Quality Indicators (HCQI) project and refer to two main actors: a coordinating agency, which proposes and collates performance data and second, data correspondents in constituent health systems, who submit data to the coordinating centre. Discussion is structured around two themes: a set of must-do's (legitimacy of the coordinating centre, validity of proposed indicators, feasibility of data collection and technical support for data correspondents) and a set of trade-offs (depth vs. breadth in the number of system elements compared, aggregation vs. granularity of data, flexibility vs. consistency of indicator definitions and inclusion criteria). Robust fulfillment of the must-do's and transparent resolution of the trade-offs both depend upon effective collaboration between the coordinating centre and data correspondents, and a close working relationship between a technical secretariat and a body of experts. Copyright © 2013 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.
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
MIPAS-ENVISAT limb-sounding measurements: trade-off study for improvement of horizontal resolution.

Science.gov (United States)

Ridolfi, Marco; Magnani, Luca; Carlotti, Massimo; Dinelli, Bianca Maria

2004-11-01

The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) is a limb-scanning spectrometer that has operated onboard the Environmental Satellite since the end of March 2002. Common features of limb-scanning experiments are both high vertical resolution and poor horizontal resolution. We exploit the two-dimensional geo-fit retrieval approach [Appl. Opt. 40, 1872-1875 (2001)] to investigate the possibility of improving the horizontal resolution of MIPAS measurements. Two different strategies are considered for this purpose, one exploiting the possibility (offered by the geo-fit analysis method) for an arbitrary definition of the retrieval grid, the other based on the possibility of saving measurement time by degrading the spectral resolution of the interferometer. The performances of the two strategies are compared in terms of the trade-off between the attained horizontal resolution and the retrieval precision. We find that for ozone it is possible to improve by a factor of 2 the horizontal resolution, which in the nominal measurement plan is approximately 530 km. This improvement corresponds to a degradation of the retrieval precision, which on average varies from a factor of 1.4 to 2.5, depending on the adopted spectral resolution.
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.
TRADE-OFF ANTARA MANAJEMEN LABA AKRUAL DAN RIIL PADA BANK KONVENSIONAL PUBLIK DI INDONESIA

Directory of Open Access Journals (Sweden)

Rianty Ontorael

2017-06-01

Full Text Available Earnings management arises from a conflicting goal between agents and principals which basically means as managers’ intentions to manipulate accounting figures in the financial statement to achieve their own interests. There are two techniques of earnings management that are usually used by management: accrual earnings management and real earnings management. The objective of this study is to examine the effect of cost of earnings management on accrual and real earnings management and the trade-off relationship between accrual and real earnings management. Using 14 publicly listed banks in the Indonesia Stock Exchange during period 2009-2013, this study shows that costs of accrual and real earnings management have significant effects on accrual and real earnings management. However, this study did not find the evidence that there is a trade-off relationship between accrual earnings management and real earnings management. The findings have implications regarding the use of costs of earnings management in considering type of earnings management’s decision in publicly listed banks in Indonesia.
a metabolic wastage model for the rate-yield trade off

Indian Academy of Sciences (India)

A METABOLIC WASTAGE MODEL FOR THE RATE-YIELD TRADE OFF. There is a growth limiting step in which an intermediate metabolite (m) has to hit a target molecule (t). ... D= rate of diffusing out. S= the rate of formation of the metabolite. The equilibrium loss decides the yield. The no. of activated targets decide the rate ...
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
A developmental window into trade-offs in executive function: the case of task switching versus response inhibition in 6-year-olds.

Science.gov (United States)

Blackwell, Katharine A; Chatham, Christopher H; Wiseheart, Melody; Munakata, Yuko

2014-09-01

Good executive function has been linked to many positive outcomes in academic performance, health, and social competence. However, some aspects of executive function may interfere with other cognitive processes. Childhood provides a unique test case for investigating such cognitive trade-offs, given the dramatic failures and developments observed during this period. For example, most children categorically switch or perseverate when asked to switch between rules on a card-sorting task. To test potential trade-offs with the development of task switching abilities, we compared 6-year-olds who switched versus perseverated in a card-sorting task on two aspects of inhibitory control: response inhibition (via a stop signal task) and interference control (via a Simon task). Across two studies, switchers showed worse response inhibition than perseverators, consistent with the idea of cognitive trade-offs; however, switchers showed better interference control than perseverators, consistent with prior work documenting benefits associated with the development of executive function. This pattern of positive and negative associations may reflect aspects of working memory (active maintenance of current goals, and clearing of prior goals) that help children focus on a single task goal but hurt in situations with conflicting goals. Implications for understanding components of executive function and their relationships across development are discussed. Copyright © 2014 Elsevier Ltd. All rights reserved.
Exploring trade-offs between fisheries and conservation of the vaquita porpoise (Phocoena sinus using an Atlantis ecosystem model.

Directory of Open Access Journals (Sweden)

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.
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
Area-delay trade-offs of texture decompressors for a graphics processing unit

Science.gov (United States)

Novoa Súñer, Emilio; Ituero, Pablo; López-Vallejo, Marisa

2011-05-01

Graphics Processing Units have become a booster for the microelectronics industry. However, due to intellectual property issues, there is a serious lack of information on implementation details of the hardware architecture that is behind GPUs. For instance, the way texture is handled and decompressed in a GPU to reduce bandwidth usage has never been dealt with in depth from a hardware point of view. This work addresses a comparative study on the hardware implementation of different texture decompression algorithms for both conventional (PCs and video game consoles) and mobile platforms. Circuit synthesis is performed targeting both a reconfigurable hardware platform and a 90nm standard cell library. Area-delay trade-offs have been extensively analyzed, which allows us to compare the complexity of decompressors and thus determine suitability of algorithms for systems with limited hardware resources.
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.
Slow Steaming in Maritime Transportation: Fundamentals, Trade-offs, and Decision Models

DEFF Research Database (Denmark)

Psaraftis, Harilaos N.; Kontovas, Christos A.

2015-01-01

burned. The purpose of this chapter is to examine the practice of slow steaming from various angles. In that context, a taxonomy of models is presented, some fundamentals are outlined, the main trade-offs are analysed, and some decision models are presented. Some examples are finally presented so...
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
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.

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
Labour Market Programmes and the Equity-Efficiency Trade-Off

DEFF Research Database (Denmark)

Filges, Trine; Kennes, John; Larsen, Birthe

2011-01-01

This paper studies optimal labour market policy in a society where differently gifted individuals can invest in training to further increase their labour market productivity and where the government seeks both efficiency and equity. Frictions in the matching process create unemployment...... and differently skilled workers face different levels of risk of unemployment. We show that in such an environment, training programmes that are targeted at the disadvantaged workers complement passive transfers (UI benefits), unlike general training subsidies. Combining passive subsidies with a training subsidy...... conditioned on the individual being unemployed (for a period) – the typical Active Labour Market Programme – creates a favourable trade-off between equity and efficiency and this encourages high spending on training...
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.
Evaluating CO2 emissions, cost, and service quality trade-offs in an urban delivery system case study

Directory of Open Access Journals (Sweden)

Erica Wygonik

2011-07-01

The results demonstrate there is not a trade-off between CO2 emissions and cost, but that these two metrics trend together. This suggests the most effective way to encourage fleet operators to limit emissions is to increase the cost of fuel or CO2 production, as this is consistent with current incentives that exist to reduce cost, and therefore emissions.
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…
The role of the noradrenergic system in the exploration-exploitation trade-off: a pharmacological study

Directory of Open Access Journals (Sweden)

Marieke Jepma

2010-08-01

Full Text Available Animal research and computational modeling have indicated an important role for the neuromodulatory locus coeruleus-norepinephrine (LC-NE system in the control of behavior. According to the adaptive gain theory, the LC-NE system is critical for optimizing behavioral performance by regulating the balance between exploitative and exploratory control states. However, crucial direct empirical tests of this theory in human subjects have been lacking. We used a pharmacological manipulation of the LC-NE system to test predictions of this theory in humans. In a double-blind parallel-groups design (N = 52, participants received 4 mg reboxetine (a selective norepinephrine reuptake inhibitor, 30 mg citalopram (a selective serotonin reuptake inhibitor or placebo. The adaptive gain theory predicted that the increased tonic NE levels induced by reboxetine would promote task disengagement and exploratory behavior. We assessed the effects of reboxetine on performance in two cognitive tasks designed to examine task (disengagement and exploitative versus exploratory behavior: a diminishing-utility task and a gambling task with a non-stationary pay-off structure. In contrast to predictions of the adaptive gain theory, we did not find differences in task (disengagement or exploratory behavior between the three experimental groups, despite demonstrable effects of the two drugs on non-specific central and autonomic nervous system parameters. Our findings suggest that the LC-NE system may not be involved in the regulation of the exploration-exploitation trade-off in humans, at least not within the context of a single task. It remains to be examined whether the LC-NE system is involved in random exploration exceeding the current task context.
System Losses and Assessment Trade Study

Energy Technology Data Exchange (ETDEWEB)

David Shropshire; Steve Piet; Nick Soelberg; Robert Cherry; Roger Henry; David Meikrantz; Greg Teske; Eric Shaber; Candido Pereira

2009-09-01

This Advanced Fuel Cycle Initiative (AFCI) study has developed new analysis methods to examine old and new technology options toward the goal of improving fuel cycle systems. We have integrated participants and information from AFCI Systems Analysis, Transmutation Fuels, Separations, and Waste Form Campaigns in the Systems Losses and Assessment Trade Study. The initial objectives of this study were to 1) increase understanding of system interdependencies and thereby identify system trade-offs that may yield important insights, 2) define impacts of separations product purity on fuel manufacture and transmutation reactivity, 3) define impacts from transuranic (TRU) losses to waste, 4) identify the interrelationships involved in fuels and separations technology performance, and 5) identify system configuration adjustments with the greatest potential for influencing system losses. While bounding and analyzing this initial problem, we also identified significantly higher-level programmatic drivers with broad implications to the current fuel cycle research charter and the general issue of a DOE complex wide need for a comprehensive and integrated nuclear material management as addressed by the new DOE Order 410.2 titled “Management of Nuclear Materials”. The initial modeling effort developed in this study for a much smaller subset of material (i.e., commercial fuel) and a selected transmutation scheme (i.e., fast reactor recycling) is a necessary first step towards examining a broader set of nuclear material management options, dispositioning strategies and integrated waste management options including potential areas of research leverage. The primary outcome from this initial study has been an enhanced integration among Campaigns and associated insights and analysis methods. Opportunities for improved understanding between the groups abound. The above lanthanide-actinide example highlights the importance of evaluating options via integration across the Campaigns
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.
Physiological Trade-Offs Along a Fast-Slow Lifestyle Continuum in Fishes: What Do They Tell Us about Resistance and Resilience to Hypoxia?

Science.gov (United States)

Stoffels, Rick J

2015-01-01

It has recently been suggested that general rules of change in ecological communities might be found through the development of functional relationships between species traits and performance. The physiological, behavioural and life-history traits of fishes are often organised along a fast-slow lifestyle continuum (FSLC). With respect to resistance (capacity for population to resist change) and resilience (capacity for population to recover from change) to environmental hypoxia, the literature suggests that traits enhancing resilience may come at the expense of traits promoting resistance to hypoxia; a trade-off may exist. Here I test whether three fishes occupying different positions along the FSLC trade-off resistance and resilience to environmental hypoxia. Static respirometry experiments were used to determine resistance, as measured by critical oxygen tension (Pcrit), and capacity for (RC) and magnitude of metabolic reduction (RM). Swimming respirometry experiments were used to determine aspects of resilience: critical (Ucrit) and optimal swimming speed (Uopt), and optimal cost of transport (COTopt). Results pertaining to metabolic reduction suggest a resistance gradient across species described by the inequality Melanotaenia fluviatilis (fast lifestyle) fishes occupying different positions on the FSLC trade-off resistance and resilience to hypoxia. However, the scope of inferences that can be drawn from an individual study is narrow, and so steps towards general, trait-based rules of fish community change along environmental gradients are discussed.
System Trade-Off Study and Opto-Thermo Analysis of a Sunshield on the MSC of the KOMPSAT-2

Directory of Open Access Journals (Sweden)

Young-Soo Kim

2003-12-01

Full Text Available The Multi-Spectral Camera (MSC is the payload of KOMPSAT-2 which is designed for earth imaging in optical and near-infrared region on a sun-synchronous orbit. The telescope in the MSC is a Ritchey-Chretien type with large aperture. The telescope structure should be well stabilized and the optical alignment should be kept steady so that best images can be achieved. However, the MSC is exposed to adverse thermal environment on the orbit which can give impacts on optical performance. Solar incidence can bring non-uniform temperature rise on the telescope tube which entails unfavorable thermal distortion. Three ways of preventing the solar radiation were proposed, which were installing external mechanical shield, internal shield, and maneuvering the spacecraft. After trade-off study, internal sun shield was selected as a practical and optimal solution to minimize the effect of the solar radiation. In addition, detailed designs of the structure and sunshield were produced and analyses have been performed. The results were assessed to verify their impacts to the image quality. It was confirmed that the internal sunshield complies with the requirements and would improve image quality.
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.
Stability for Function Trade-Offs in the Enolase Superfamily 'Catalytic Module'

Energy Technology Data Exchange (ETDEWEB)

Nagatani, R.A.; Gonzalez, A.; Shoichet, B.K.; Brinen, L.S.; Babbitt, P.C.; /UC, San Francisco /SLAC, SSRL

2007-07-12

Enzyme catalysis reflects a dynamic interplay between charged and polar active site residues that facilitate function, stabilize transition states, and maintain overall protein stability. Previous studies show that substituting neutral for charged residues in the active site often significantly stabilizes a protein, suggesting a stability trade-off for functionality. In the enolase superfamily, a set of conserved active site residues (the ''catalytic module'') has repeatedly been used in nature in the evolution of many different enzymes for the performance of unique overall reactions involving a chemically diverse set of substrates. This catalytic module provides a robust solution for catalysis that delivers the common underlying partial reaction that supports all of the different overall chemical reactions of the superfamily. As this module has been so broadly conserved in the evolution of new functions, we sought to investigate the extent to which it follows the stability-function trade-off. Alanine substitutions were made for individual residues, groups of residues, and the entire catalytic module of o-succinylbenzoate synthase (OSBS), a member of the enolase superfamily from Escherichia coli. Of six individual residue substitutions, four (K131A, D161A, E190A, and D213A) substantially increased protein stability (by 0.46-4.23 kcal/mol), broadly consistent with prediction of a stability-activity trade-off. The residue most conserved across the superfamily, E190, is by far the most destabilizing. When the individual substitutions were combined into groups (as they are structurally and functionally organized), nonadditive stability effects emerged, supporting previous observations that residues within the module interact as two functional groups within a larger catalytic system. Thus, whereas the multiple-mutant enzymes D161A/E190A/D213A and K131A/K133A/D161A/E190A/D213A/K235A (termed 3KDED) are stabilized relative to the wild-type enzyme (by 1
Egg number-egg size: an important trade-off in parasite life history strategies.

Science.gov (United States)

Cavaleiro, Francisca I; Santos, Maria J

2014-03-01

Parasites produce from just a few to many eggs of variable size, but our understanding of the factors driving variation in these two life history traits at the intraspecific level is still very fragmentary. This study evaluates the importance of performing multilevel analyses on egg number and egg size, while characterising parasite life history strategies. A total of 120 ovigerous females of Octopicola superba (Copepoda: Octopicolidae) (one sample (n=30) per season) were characterised with respect to different body dimensions (total length; genital somite length) and measures of reproductive effort (fecundity; mean egg diameter; total reproductive effort; mean egg sac length). While endoparasites are suggested to follow both an r- and K-strategy simultaneously, the evidence found in this and other studies suggests that environmental conditions force ectoparasites into one of the two alternatives. The positive and negative skewness of the distributions of fecundity and mean egg diameter, respectively, suggest that O. superba is mainly a K-strategist (i.e. produces a relatively small number of large, well provisioned eggs). Significant sample differences were recorded concomitantly for all body dimensions and measures of reproductive effort, while a general linear model detected a significant influence of season*parasite total length in both egg number and size. This evidence suggests adaptive phenotypic plasticity in body dimensions and size-mediated changes in egg production. Seasonal changes in partitioning of resources between egg number and size resulted in significant differences in egg sac length but not in total reproductive effort. Evidence for a trade-off between egg number and size was found while controlling for a potential confounding effect of parasite total length. However, this trade-off became apparent only at high fecundity levels, suggesting a state of physiological exhaustion. Copyright © 2014 Australian Society for Parasitology Inc. Published
"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.
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.
Constant versus variable response signal delays in speed accuracy trade-offs : Effects of advance preparation for processing time

OpenAIRE

Miller, Jeff; Sproesser, Gudrun; Ulrich, Rolf

2008-01-01

In two experiments, we used response signals (RSs) to control processing time and trace out speed accuracy trade-off (SAT) functions in a difficult perceptual discrimination task. Each experiment compared performance in blocks of trials with constant and, hence, temporally predictable RS lags against performance in blocks with variable, unpredictable RS lags. In both experiments, essentially equivalent SAT functions were observed with constant and variable RS lags. We conclude that there is l...
Trade-offs in thermal adaptation: the need for a molecular to ecological integration.

Science.gov (United States)

Pörtner, Hans O; Bennett, Albert F; Bozinovic, Francisco; Clarke, Andrew; Lardies, Marco A; Lucassen, Magnus; Pelster, Bernd; Schiemer, Fritz; Stillman, Jonathon H

2006-01-01

Through functional analyses, integrative physiology is able to link molecular biology with ecology as well as evolutionary biology and is thereby expected to provide access to the evolution of molecular, cellular, and organismic functions; the genetic basis of adaptability; and the shaping of ecological patterns. This paper compiles several exemplary studies of thermal physiology and ecology, carried out at various levels of biological organization from single genes (proteins) to ecosystems. In each of those examples, trade-offs and constraints in thermal adaptation are addressed; these trade-offs and constraints may limit species' distribution and define their level of fitness. For a more comprehensive understanding, the paper sets out to elaborate the functional and conceptual connections among these independent studies and the various organizational levels addressed. This effort illustrates the need for an overarching concept of thermal adaptation that encompasses molecular, organellar, cellular, and whole-organism information as well as the mechanistic links between fitness, ecological success, and organismal physiology. For this data, the hypothesis of oxygen- and capacity-limited thermal tolerance in animals provides such a conceptual framework and allows interpreting the mechanisms of thermal limitation of animals as relevant at the ecological level. While, ideally, evolutionary studies over multiple generations, illustrated by an example study in bacteria, are necessary to test the validity of such complex concepts and underlying hypotheses, animal physiology frequently is constrained to functional studies within one generation. Comparisons of populations in a latitudinal cline, closely related species from different climates, and ontogenetic stages from riverine clines illustrate how evolutionary information can still be gained. An understanding of temperature-dependent shifts in energy turnover, associated with adjustments in aerobic scope and performance
Haste makes waste but condition matters: molt rate-feather quality trade-off in a sedentary songbird.

Directory of Open Access Journals (Sweden)

Csongor I Vágási

Full Text Available The trade-off between current and residual reproductive values is central to life history theory, although the possible mechanisms underlying this trade-off are largely unknown. The 'molt constraint' hypothesis suggests that molt and plumage functionality are compromised by the preceding breeding event, yet this candidate mechanism remains insufficiently explored.The seasonal change in photoperiod was manipulated to accelerate the molt rate. This treatment simulates the case of naturally late-breeding birds. House sparrows Passer domesticus experiencing accelerated molt developed shorter flight feathers with more fault bars and body feathers with supposedly lower insulation capacity (i.e. shorter, smaller, with a higher barbule density and fewer plumulaceous barbs. However, the wing, tail and primary feather lengths were shorter in fast-molting birds if they had an inferior body condition, which has been largely overlooked in previous studies. The rachis width of flight feathers was not affected by the treatment, but it was still condition-dependent.This study shows that sedentary birds might face evolutionary costs because of the molt rate-feather quality conflict. This is the first study to experimentally demonstrate that (1 molt rate affects several aspects of body feathers as well as flight feathers and (2 the costly effects of rapid molt are condition-specific. We conclude that molt rate and its association with feather quality might be a major mediator of life history trade-offs. Our findings also suggest a novel advantage of early breeding, i.e. the facilitation of slower molt and the condition-dependent regulation of feather growth.
Haste Makes Waste but Condition Matters: Molt Rate–Feather Quality Trade-Off in a Sedentary Songbird

Science.gov (United States)

Vágási, Csongor I.; Pap, Péter L.; Vincze, Orsolya; Benkő, Zoltán; Marton, Attila; Barta, Zoltán

2012-01-01

Background The trade-off between current and residual reproductive values is central to life history theory, although the possible mechanisms underlying this trade-off are largely unknown. The ‘molt constraint’ hypothesis suggests that molt and plumage functionality are compromised by the preceding breeding event, yet this candidate mechanism remains insufficiently explored. Methodology/Principal Findings The seasonal change in photoperiod was manipulated to accelerate the molt rate. This treatment simulates the case of naturally late-breeding birds. House sparrows Passer domesticus experiencing accelerated molt developed shorter flight feathers with more fault bars and body feathers with supposedly lower insulation capacity (i.e. shorter, smaller, with a higher barbule density and fewer plumulaceous barbs). However, the wing, tail and primary feather lengths were shorter in fast-molting birds if they had an inferior body condition, which has been largely overlooked in previous studies. The rachis width of flight feathers was not affected by the treatment, but it was still condition-dependent. Conclusions/Significance This study shows that sedentary birds might face evolutionary costs because of the molt rate–feather quality conflict. This is the first study to experimentally demonstrate that (1) molt rate affects several aspects of body feathers as well as flight feathers and (2) the costly effects of rapid molt are condition-specific. We conclude that molt rate and its association with feather quality might be a major mediator of life history trade-offs. Our findings also suggest a novel advantage of early breeding, i.e. the facilitation of slower molt and the condition-dependent regulation of feather growth. PMID:22808221
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.

A study of rotor and platform design trade-offs for large-scale floating vertical axis wind turbines

Science.gov (United States)

Griffith, D. Todd; Paquette, Joshua; Barone, Matthew; Goupee, Andrew J.; Fowler, Matthew J.; Bull, Diana; Owens, Brian

2016-09-01

Vertical axis wind turbines are receiving significant attention for offshore siting. In general, offshore wind offers proximity to large populations centers, a vast & more consistent wind resource, and a scale-up opportunity, to name a few beneficial characteristics. On the other hand, offshore wind suffers from high levelized cost of energy (LCOE) and in particular high balance of system (BoS) costs owing to accessibility challenges and limited project experience. To address these challenges associated with offshore wind, Sandia National Laboratories is researching large-scale (MW class) offshore floating vertical axis wind turbines (VAWTs). The motivation for this work is that floating VAWTs are a potential transformative technology solution to reduce offshore wind LCOE in deep-water locations. This paper explores performance and cost trade-offs within the design space for floating VAWTs between the configurations for the rotor and platform.
Ecological implications of a flower size/number trade-off in tropical forest trees.

Directory of Open Access Journals (Sweden)

Chris J Kettle

2011-02-01

Full Text Available In angiosperms, flower size commonly scales negatively with number. The ecological consequences of this trade-off for tropical trees remain poorly resolved, despite their potential importance for tropical forest conservation. We investigated the flower size number trade-off and its implications for fecundity in a sample of tree species from the Dipterocarpaceae on Borneo.We combined experimental exclusion of pollinators in 11 species, with direct and indirect estimates of contemporary pollen dispersal in two study species and published estimates of pollen dispersal in a further three species to explore the relationship between flower size, pollinator size and mean pollen dispersal distance. Maximum flower production was two orders of magnitude greater in small-flowered than large-flowered species of Dipterocarpaceae. In contrast, fruit production was unrelated to flower size and did not differ significantly among species. Small-flowered species had both smaller-sized pollinators and lower mean pollination success than large-flowered species. Average pollen dispersal distances were lower and frequency of mating between related individuals was higher in a smaller-flowered species than a larger-flowered confamilial. Our synthesis of pollen dispersal estimates across five species of dipterocarp suggests that pollen dispersal scales positively with flower size.Trade-offs embedded in the relationship between flower size and pollination success contribute to a reduction in the variance of fecundity among species. It is therefore plausible that these processes could delay competitive exclusion and contribute to maintenance of species coexistence in this ecologically and economically important family of tropical trees. These results have practical implications for tree species conservation and restoration. Seed collection from small-flowered species may be especially vulnerable to cryptic genetic erosion. Our findings also highlight the potential for
Quantifying design trade-offs of beryllium targets on NIF

Science.gov (United States)

Yi, S. A.; Zylstra, A. B.; Kline, J. L.; Loomis, E. N.; Kyrala, G. A.; Shah, R. C.; Perry, T. S.; Kanzleiter, R. J.; Batha, S. H.; MacLaren, S. A.; Ralph, J. E.; Masse, L. P.; Salmonson, J. D.; Tipton, R. E.; Callahan, D. A.; Hurricane, O. A.

2017-10-01

An important determinant of target performance is implosion kinetic energy, which scales with the capsule size. The maximum achievable performance for a given laser is thus related to the largest capsule that can be imploded symmetrically, constrained by drive uniformity. A limiting factor for symmetric radiation drive is the ratio of hohlraum to capsule radii, or case-to-capsule ratio (CCR). For a fixed laser energy, a larger hohlraum allows for driving bigger capsules symmetrically at the cost of reduced peak radiation temperature (Tr). Beryllium ablators may thus allow for unique target design trade-offs due to their higher ablation efficiency at lower Tr. By utilizing larger hohlraum sizes than most modern NIF designs, beryllium capsules thus have the potential to operate in unique regions of the target design parameter space. We present design simulations of beryllium targets with a large CCR = 4.3 3.7 . These are scaled surrogates of large hohlraum low Tr beryllium targets, with the goal of quantifying symmetry tunability as a function of CCR. This work performed under the auspices of the U.S. DOE by LANL under contract DE-AC52- 06NA25396, and by LLNL under Contract DE-AC52-07NA27344.
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 ...
[Eng] Voting for Parties or for Candidates? The Trade-Off Between Party and Personal Representation in Spanish Regional and Local Elections

Directory of Open Access Journals (Sweden)

Pablo Barberá

2010-01-01

Full Text Available When voters cast their ballot, are they choosing a candidate or a party? Electoral systems have a significant impact on how this question is answered in each country. As previous literature has shown, some electoral rules foster a more personal representation, while others strengthen the intermediary role of parties. In this paper I maintain that there exists a trade-off between these two types of representation. To empirically verify its existence and how it works, I have chosen local and regional elections in Spain as a case study. Given that they take place simultaneously under similar electoral systems, they can be considered a natural experiment for the study of this trade-off, which allows me to overcome the potential problems of endogeneity present in previous studies. By measuring the significance of ideological closeness and candidate evaluations in voters? decisions at each level, it is shown that the importance of personal representation increases in local elections at the expense of a less frequent use of ideological proximity as an informational shortcut, thus confirming the existence of the trade-off.
A novel lateral IGBT with a controlled anode for on-off-state loss trade-off improvement

International Nuclear Information System (INIS)

Chen Wensuo; Zhang Bo; Fang Jian; Li Zhaoji

2011-01-01

A new lateral insulated-gate bipolar transistor with a controlled anode (CA-LIGBT) on silicon-on-insulator (SOI) substrate is reported. Benefiting from both the enhanced conductivity modulation effect and the high resistance controlled electron extracting path, CA-LIGBT has a faster turn-off speed and lower forward drop, and the trade-off between off-state and on-state losses is better than that of state-of-the-art 3-D NCA-LIGBT, which we presented earlier. As the simulation results show, the ratios of figure of merit (FOM) for CA-LIGBT compared to that of 3-D NCA-LIGBT and conventional LIGBT are 1.45: 1 and 59.53: 1, respectively. And, the new devices can be created by using additional silicon direct bonding (SDB). So, from the power efficiency point of view, the proposed CA-LIGBT is a promising device for use in power ICs. (semiconductor devices)
A novel lateral IGBT with a controlled anode for on-off-state loss trade-off improvement

Institute of Scientific and Technical Information of China (English)

Chen Wensuo; Zhang Bo; Fang Jian; Li Zhaoji

2011-01-01

A new lateral insulated-gate bipolar transistor with a controlled anode (CA-LIGBT) on silicon-oninsulator (SOI) substrate is reported.Benefiting from both the enhanced conductivity modulation effect and the high resistance controlled electron extracting path,CA-LIGBT has a faster turn-off speed and lower forward drop,and the trade-off between off-state and on-state losses is better than that of state-of-the-art 3-D NCA-LIGBT,which we presented earlier.As the simulation results show,the ratios of figure of merit (FOM) for CA-LIGBT compared to that of3-D NCA-LIGBT and conventional LIGBT are 1.45:1 and 59.53:1,respectively.And,the new devices can be created by using additional silicon direct bonding (SDB).So,from the power efficiency point of view,the proposed CA-LIGBT is a promising device for use in power ICs.
Method for Analyzing Trade-offs in Biomass Management in Smallholder Farming Systems Based on Mass Balance: A Case Study in Tajikistan's Foothills

Directory of Open Access Journals (Sweden)

Sebastian Ruppen

2016-02-01

Full Text Available In smallholder farming systems, especially in mountainous areas, households face trade-offs between meeting short-term human needs and ensuring long-term soil productivity. Improved biomass management can help break the downward spiral of overexploitation of natural resources, land degradation, and productivity decline, and support more sustainable use of marginal land. Mixed crop/livestock systems are often carefully balanced to minimize risks. Thus, when planning interventions, profound systems knowledge is crucial. However, the data required for system characterization are often scarce, and original field studies are thus necessary. The aim of this research, a case study in Tajikistan, was to improve systems understanding of the biomass cycle in crop/livestock systems in order to quantify the obstacles to the spread of sustainable land management technologies to farming households. It aimed to establish a database and methods of rapid data collection to quantify the stocks and flows of biomass, with a focus on mass balances, and to evaluate smallholders’ biomass management options and trade-offs. Data collection included household interviews, secondary literature, and reference data sets from global sources. Trade-off analysis focused on household-level self-supply of food, fodder, and fuel by farmers with different sizes of smallholdings, and their potential for on-farm recycling of organic matter. Results indicate that food self-supply by small and medium smallholders is insufficient and fodder sources are scarce. Fodder scarcity means that application of crop byproducts to soils is unlikely. Animal dung is largely used as fuel. Firewood needs exceed on-farm wood production, leading to deforestation. The approach presented facilitates an understanding of current and potential agricultural land interventions in the crop/livestock farming systems prevailing in mountainous areas.
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

% might be attractive for cropland expansion and thus would require protection from recultivation. Agroenvironmental, accessibility, and socio-economic constraints suggested that the remaining 30.6 (25.7-30.6 Mha of abandoned croplands were unlikely to provide important contributions to future crop production at current wheat prices but could provide various ecosystem services, and some could support extensive livestock production. Political and institutional support could foster recultivation by supporting investments in agriculture and rural demographic revitalization. Reclaiming potentially available cropland in the study region could provide a notable contribution to global grain production, with relatively low environmental trade-offs compared with tropical frontiers, but is not a panacea to address global issues of food security or reduce land-use pressure on tropical ecosystems
The effect of growth conditions on the seed size/number trade-off.

Directory of Open Access Journals (Sweden)

Cloé Paul-Victor

2009-09-01

Full Text Available If the amount of resources allocated to reproduction (K is fixed, then an increase in seed mass (S can only be achieved by a decrease in seed number (n = K/S. Thus, log(n = log(K-log(S producing a slope of -1 when seed mass and number are plotted on log-log axes. However, in comparative studies, empirical support for a slope of -1 is limited and contentious, leading some to question the utility of this concept.First, we show that the expected slope depends on whether genotypes and species producing seeds of different mass are expected to reach the same adult size and that this in turn depends partly on the nature of growth. Second, we present experimental results using a population of recombinant inbred lines (RILs of Arabidopsis thaliana. When these RILs are grown in large pots with plentiful nutrients, they exhibit a trade-off between seed size and number with a slope of -1.68 (+/-0.18 on log-log axes. This occurs because of genetic correlations between seed mass and adult size so that, under the right growth conditions, lines producing lighter seeds have the genetic potential to produce larger rosettes and hence a greater total mass of seeds. We re-grew lines in small pots (10 and 40 mm diameter in a nutrient-poor substrate so that final adult size was heavily restricted by pot size.Under our growth conditions, small-seeded lines were unable to produce a greater total mass of seeds. Hence a trade-off emerged between seed mass and seed number with a slope of -1.166+/-0.319 on log-log axes in 40-mm diameter pots (close to the expected value of -1, although the slope was 0.132+/-0.263 in 10-mm diameter pots, demonstrating that the nature of the trade-off is sensitive to the growth conditions.
Investigation of cone-beam CT image quality trade-off for image-guided radiation therapy

Science.gov (United States)

Bian, Junguo; Sharp, Gregory C.; Park, Yang-Kyun; Ouyang, Jinsong; Bortfeld, Thomas; El Fakhri, Georges

2016-05-01

It is well-known that projections acquired over an angular range slightly over 180° (so-called short scan) are sufficient for fan-beam reconstruction. However, due to practical imaging conditions (projection data and reconstruction image discretization, physical factors, and data noise), the short-scan reconstructions may have different appearances and properties from the full-scan (scans over 360°) reconstructions. Nevertheless, short-scan configurations have been used in applications such as cone-beam CT (CBCT) for head-neck-cancer image-guided radiation therapy (IGRT) that only requires a small field of view due to the potential reduced imaging time and dose. In this work, we studied the image quality trade-off for full, short, and full/short scan configurations with both conventional filtered-backprojection (FBP) reconstruction and iterative reconstruction algorithms based on total-variation (TV) minimization for head-neck-cancer IGRT. Anthropomorphic and Catphan phantoms were scanned at different exposure levels with a clinical scanner used in IGRT. Both visualization- and numerical-metric-based evaluation studies were performed. The results indicate that the optimal exposure level and number of views are in the middle range for both FBP and TV-based iterative algorithms and the optimization is object-dependent and task-dependent. The optimal view numbers decrease with the total exposure levels for both FBP and TV-based algorithms. The results also indicate there are slight differences between FBP and TV-based iterative algorithms for the image quality trade-off: FBP seems to be more in favor of larger number of views while the TV-based algorithm is more robust to different data conditions (number of views and exposure levels) than the FBP algorithm. The studies can provide a general guideline for image-quality optimization for CBCT used in IGRT and other applications.
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
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...
Plumage quality mediates a life-history trade-off in a migratory bird.

Science.gov (United States)

Podlaszczuk, Patrycja; Kamiński, Maciej; Włodarczyk, Radosław; Kaczmarek, Krzysztof; Janiszewski, Tomasz; Minias, Piotr

2016-01-01

Moult is one of the most costly activities in the annual cycle of birds and most avian species separate moult from other energy-demanding activities, such as migration. To this end, young birds tend to undergo the first post-juvenile moult before the onset of migration, but in some species the time window for the pre-migratory feather replacement is too narrow. We hypothesized that in such species an increased investment in the structural quality of juvenile feathers may allow to retain juvenile plumage throughout the entire migratory period and delay moult until arriving at wintering grounds, thus avoiding a moult-migration overlap. The effect of juvenile plumage quality on the occurrence of moult-migration overlap was studied in a migratory shorebird, the common snipe Gallinago gallinago . Ca. 400 of first-year common snipe were captured during their final stage of autumn migration through Central Europe. The quality of juvenile feathers was assessed as the mass-length residuals of retained juvenile rectrices. Condition of migrating birds was assessed with the mass of accumulated fat reserves and whole-blood hemoglobin concentration. Path analysis was used to disentangle complex interrelationships between plumage quality, moult and body condition. Snipe which grew higher-quality feathers in the pre-fledging period were less likely to initiate moult during migration. Individuals moulting during migration had lower fat loads and hemoglobin concentrations compared to non-moulting birds, suggesting a trade-off in resource allocation, where energetic costs of moult reduced both energy reserves available for migration and resources available for maintenance of high oxygen capacity of blood. The results of this study indicate that a major life-history trade-off in a migratory bird may be mediated by the quality of juvenile plumage. This is consistent with a silver spoon effect, where early-life investment in feather quality affects future performance of birds during
Nigeria in World Ginger Trade: An analysis of performance from ...

African Journals Online (AJOL)

This study assessed the performance of Nigeria in the world ginger trade using available secondary data from the United Nations commodity trade statistics. The trade performance of Nigeria was based on world ginger export characteristics, value of trade and quantity traded from 2008 to 2012 assessed on yearly and ...
The emotion-induced memory trade-off: more than an effect of overt attention?

Science.gov (United States)

Steinmetz, Katherine R Mickley; Kensinger, Elizabeth A

2013-01-01

Although it has been suggested that many effects of emotion on memory are attributable to attention, in the present study we addressed the hypothesis that such effects may relate to a number of different factors during encoding or postencoding. One way to look at the effects of emotion on memory is by examining the emotion-induced memory trade-off, whereby enhanced memory for emotional items often comes at the cost of memory for surrounding background information. We present evidence that this trade-off cannot be explained solely by overt attention (measured via eyetracking) directed to the emotional items during encoding. Participants did not devote more overt attention to emotional than to neutral items when those items were selectively remembered (at the expense of their backgrounds). Only when participants were asked to answer true/false questions about the items and the backgrounds--a manipulation designed to affect both overt attention and poststimulus elaboration--was there a reduction in selective emotional item memory due to an increase in background memory. These results indicate that the allocation of overt visual attention during encoding is not sufficient to predict the occurrence of selective item memory for emotional items.
An internet graph model based on trade-off optimization

Science.gov (United States)

Alvarez-Hamelin, J. I.; Schabanel, N.

2004-03-01

This paper presents a new model for the Internet graph (AS graph) based on the concept of heuristic trade-off optimization, introduced by Fabrikant, Koutsoupias and Papadimitriou in[CITE] to grow a random tree with a heavily tailed degree distribution. We propose here a generalization of this approach to generate a general graph, as a candidate for modeling the Internet. We present the results of our simulations and an analysis of the standard parameters measured in our model, compared with measurements from the physical Internet graph.
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
Drought tolerance of tropical tree species : functional traits, trade-offs and species distribution

NARCIS (Netherlands)

Markesteijn, L.

2010-01-01

KEY-WORDS:
Bolivia, drought tolerance, shade tolerance, functional traits, trade-offs, ecophysiology, species distribution
Tropical forests occur under rainfall regimes that vary greatly in the rainfall pattern and frequency and intensity of drought. Consequently water availability is
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.

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.
Thermotolerant Yeast Strains Adapted by Laboratory Evolution Show Trade-Off at Ancestral Temperatures and Preadaptation to Other Stresses

DEFF Research Database (Denmark)

Caspeta, Luis; Nielsen, Jens

2015-01-01

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...... 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...
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
Spiders in Motion: Demonstrating Adaptation, Structure-Function Relationships, and Trade-Offs in Invertebrates

Science.gov (United States)

Bowlin, Melissa S.; McLeer, Dorothy F.; Danielson-Francois, Anne M.

2014-01-01

Evolutionary history and structural considerations constrain all aspects of animal physiology. Constraints on invertebrate locomotion are especially straightforward for students to observe and understand. In this exercise, students use spiders to investigate the concepts of adaptation, structure-function relationships, and trade-offs. Students…
Evaluation of trade-offs in costs and environmental impacts for returnable packaging implementation

Science.gov (United States)

Jarupan, Lerpong; Kamarthi, Sagar V.; Gupta, Surendra M.

2004-02-01

The main thrust of returnable packaging these days is to provide logistical services through transportation and distribution of products and be environmentally friendly. Returnable packaging and reverse logistics concepts have converged to mitigate the adverse effect of packaging materials entering the solid waste stream. Returnable packaging must be designed by considering the trade-offs between costs and environmental impact to satisfy manufacturers and environmentalists alike. The cost of returnable packaging entails such items as materials, manufacturing, collection, storage and disposal. Environmental impacts are explicitly linked with solid waste, air pollution, and water pollution. This paper presents a multi-criteria evaluation technique to assist decision-makers for evaluating the trade-offs in costs and environmental impact during the returnable packaging design process. The proposed evaluation technique involves a combination of multiple objective integer linear programming and analytic hierarchy process. A numerical example is used to illustrate the methodology.
The trade-off between expected risk and the potential for large accidents

International Nuclear Information System (INIS)

Niehaus, F.; de Leon, G.; Cullingford, M.

1984-01-01

This paper, by Niehaus, de Leon, and Cullingford, examines the relationship between expected risk and the potential for large accidents. Using historical data for airplane accidents from 19471980, the authors show that a reduction of the expected value of risk often results in an increase in the potential for catastrophe. Phrased differently, the authors suggest that there may be a nenessary trade-off between high-probability/low-consequence risk and low-probability/high-consequence risk. The implications of this study for energy systems, for oil and gas supply, and for nuclear systems are also given
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.
A Comparative Survey of Adaptive Codec Solutions for VoIP over Multirate WLANs: A Capacity versus Quality Performance Trade-Off

Directory of Open Access Journals (Sweden)

Sfairopoulou A

2011-01-01

Full Text Available In multi-rate WLANs, users can suffer transmission rate changes due to the link adaptation mechanism. This results in a variable capacity channel, which is very hostile for VoIP and can cause serious quality of service (QoS degradation in all active calls. Various codec adaptation mechanisms have been proposed as a solution to this, as well as to solve congestion problems on WLAN environments. Here, these solutions are presented, categorized according to the adaptation policy and scenario they implement, and evaluated at call-level in terms of the resulting blocking and dropping probabilities, as well as the perceived voice quality. To define a common performance metric, a new index named VGoS-factor is presented, which, by combining these capacity and quality indicators, can provide an overall view of the capacity versus quality trade-off of the proposed mechanisms and consequently help in choosing the adequate policy for each scenario.
Designing multi-reservoir system designs via efficient water-energy-food nexus trade-offs - Selecting new hydropower dams for the Blue Nile and Nepal's Koshi Basin

Science.gov (United States)

Harou, J. J.; Hurford, A.; Geressu, R. T.

2015-12-01

Many of the world's multi-reservoir water resource systems are being considered for further development of hydropower and irrigation aiming to meet economic, political and ecological goals. Complex river basins serve many needs so how should the different proposed groupings of reservoirs and their operations be evaluated? How should uncertainty about future supply and demand conditions be factored in? What reservoir designs can meet multiple goals and perform robustly in a context of global change? We propose an optimized multi-criteria screening approach to identify best performing designs, i.e., the selection, size and operating rules of new reservoirs within multi-reservoir systems in a context of deeply uncertain change. Reservoir release operating rules and storage sizes are optimized concurrently for each separate infrastructure design under consideration across many scenarios representing plausible future conditions. Outputs reveal system trade-offs using multi-dimensional scatter plots where each point represents an approximately Pareto-optimal design. The method is applied to proposed Blue Nile River reservoirs in Ethiopia, where trade-offs between capital costs, total and firm energy output, aggregate storage and downstream irrigation and energy provision for the best performing designs are evaluated. The impact of filling period for large reservoirs is considered in a context of hydrological uncertainty. The approach is also applied to the Koshi basin in Nepal where combinations of hydropower storage and run-of-river dams are being considered for investment. We show searching for investment portfolios that meet multiple objectives provides stakeholders with a rich view on the trade-offs inherent in the nexus and how different investment bundles perform differently under plausible futures. Both case-studies show how the proposed approach helps explore and understand the implications of investing in new dams in a global change context.
Mother and offspring fitness in an insect with maternal care: phenotypic trade-offs between egg number, egg mass and egg care

Science.gov (United States)

2014-01-01

Background Oviparous females have three main options to increase their reproductive success: investing into egg number, egg mass and/or egg care. Although allocating resources to either of these three components is known to shape offspring number and size, potential trade-offs among them may have key impacts on maternal and offspring fitness. Here, we tested the occurrence of phenotypic trade-offs between egg number, egg mass and maternal expenditure on egg care in the European earwig, Forficula auricularia, an insect with pre- and post-hatching forms of maternal care. In particular, we used a series of laboratory observations and experiments to investigate whether these three components non-additively influenced offspring weight and number at hatching, and whether they were associated with potential costs to females in terms of future reproduction. Results We found negative associations between egg number and mass as well as between egg number and maternal expenditure on egg care. However, these trade-offs could only be detected after statistically correcting for female weight at egg laying. Hatchling number was not determined by single or additive effects among the three life-history traits, but instead by pairwise interactions among them. In particular, offspring number was positively associated with the number of eggs only in clutches receiving high maternal care or consisting of heavy eggs, and negatively associated with mean egg mass in clutches receiving low care. In contrast, offspring weight was positively associated with egg mass only. Finally, maternal expenditure on egg care reduced their future reproduction, but this effect was only detected when mothers were experimentally isolated from their offspring at egg hatching. Conclusions Overall, our study reveals simultaneous trade-offs between the number, mass and care of eggs. It also demonstrates that these factors interact in their impact on offspring production, and that maternal expenditure on egg
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)
Trade-offs between xylem hydraulic properties, wood anatomy and yield in Populus.

Science.gov (United States)

Hajek, Peter; Leuschner, Christoph; Hertel, Dietrich; Delzon, Sylvain; Schuldt, Bernhard

2014-07-01

Trees face the dilemma that achieving high plant productivity is accompanied by a risk of drought-induced hydraulic failure due to a trade-off in the trees' vascular system between hydraulic efficiency and safety. By investigating the xylem anatomy of branches and coarse roots, and measuring branch axial hydraulic conductivity and vulnerability to cavitation in 4-year-old field-grown aspen plants of five demes (Populus tremula L. and Populus tremuloides Michx.) differing in growth rate, we tested the hypotheses that (i) demes differ in wood anatomical and hydraulic properties, (ii) hydraulic efficiency and safety are related to xylem anatomical traits, and (iii) aboveground productivity and hydraulic efficiency are negatively correlated to cavitation resistance. Significant deme differences existed in seven of the nine investigated branch-related anatomical and hydraulic traits but only in one of the four coarse-root-related anatomical traits; this likely is a consequence of high intra-plant variation in root morphology and the occurrence of a few 'high-conductivity roots'. Growth rate was positively related to branch hydraulic efficiency (xylem-specific conductivity) but not to cavitation resistance; this indicates that no marked trade-off exists between cavitation resistance and growth. Both branch hydraulic safety and hydraulic efficiency significantly depended on vessel size and were related to the genetic distance between the demes, while the xylem pressure causing 88% loss of hydraulic conductivity (P88 value) was more closely related to hydraulic efficiency than the commonly used P50 value. Deme-specific variation in the pit membrane structure may explain why vessel size was not directly linked to growth rate. We conclude that branch hydraulic efficiency is an important growth-influencing trait in aspen, while the assumed trade-off between productivity and hydraulic safety is weak. © The Author 2014. Published by Oxford University Press. All rights reserved
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.
The Logistics Performance Effect in International Trade

Directory of Open Access Journals (Sweden)

Azmat Gani

2017-12-01

Full Text Available The continuous growth in world trade depends on the efficiency of trade support structures such as the logistics services. Despite logistics integral role in supporting commercial activities, there has generally been a low level of analysis and trade policy research focus from trade practitioners. This paper explores the effect of logistics performance in international trade. The analysis draws on overall logistics performance as well as disaggregated measures of logistics specificities data for a large sample of countries. The empirical analysis involved the estimation of standard export and import equations incorporating measures of logistics performance. The findings show that the overall logistics performance is positively and statistically significantly correlated with exports and imports. The analysis is also extended by investigating if logistics specificities mattered for international trade. The findings reveal that several dimensions capturing logistics performance have statistically significant and positive effect, mostly on exports. The main policy implication is that continuous investment in logistics infrastructure and services can positively impact international trade.
Measuring performance at trade shows

DEFF Research Database (Denmark)

Hansen, Kåre

2004-01-01

Trade shows is an increasingly important marketing activity to many companies, but current measures of trade show performance do not adequately capture dimensions important to exhibitors. Based on the marketing literature's outcome and behavior-based control system taxonomy, a model is built...... that captures a outcome-based sales dimension and four behavior-based dimensions (i.e. information-gathering, relationship building, image building, and motivation activities). A 16-item instrument is developed for assessing exhibitors perceptions of their trade show performance. The paper presents evidence...
Quantifying uncertainty and trade-offs in resilience assessments

Directory of Open Access Journals (Sweden)

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
[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-Offs in Multi-Purpose Land Use under Land Degradation

Directory of Open Access Journals (Sweden)

Paul L. G. Vlek

2017-11-01

Full Text Available Land provides a host of ecosystem services, of which the provisioning services are often considered paramount. As the demand for agricultural products multiplies, other ecosystem services are being degraded or lost entirely. Finding a sustainable trade-off between food production and one or more of other ecosystem services, given the variety of stakeholders, is a matter of optimizing land use in a dynamic and complex socio-ecological system. Land degradation reduces our options to meet both food demands and environmental needs. In order to illustrate this trade-off dilemma, four representative services, carbon sinks, water storage, biodiversity, and space for urbanization, are discussed here based on a review of contemporary literature that cuts across the domain of ecosystem services that are provided by land. Agricultural research will have to expand its focus from the field to the landscape level and in the process examine the cost of production that internalizes environmental costs. In some situations, the public cost of agriculture in marginal environments outweighs the private gains, even with the best technologies in place. Land use and city planners will increasingly have to address the cost of occupying productive agricultural land or the conversion of natural habitats. Landscape designs and urban planning should aim for the preservation of agricultural land and the integrated management of land resources by closing water and nutrient cycles, and by restoring biodiversity.
Ocean zoning for conservation, fisheries and marine renewable energy: assessing trade-offs and co-location opportunities.

Science.gov (United States)

Yates, Katherine L; Schoeman, David S; Klein, Carissa J

2015-04-01

Oceans, particularly coastal areas, are getting busier and within this increasingly human-dominated seascape, marine biodiversity continues to decline. Attempts to maintain and restore marine biodiversity are becoming more spatial, principally through the designation of marine protected areas (MPAs). MPAs compete for space with other uses, and the emergence of new industries, such as marine renewable energy generation, will increase competition for space. Decision makers require guidance on how to zone the ocean to conserve biodiversity, mitigate conflict and accommodate multiple uses. Here we used empirical data and freely available planning software to identified priority areas for multiple ocean zones, which incorporate goals for biodiversity conservation, two types of renewable energy, and three types of fishing. We developed an approached to evaluate trade-offs between industries and we investigated the impacts of co-locating some fishing activities within renewable energy sites. We observed non-linear trade-offs between industries. We also found that different subsectors within those industries experienced very different trade-off curves. Incorporating co-location resulted in significant reductions in cost to the fishing industry, including fisheries that were not co-located. Co-location also altered the optimal location of renewable energy zones with planning solutions. Our findings have broad implications for ocean zoning and marine spatial planning. In particular, they highlight the need to include industry subsectors when assessing trade-offs and they stress the importance of considering co-location opportunities from the outset. Our research reinforces the need for multi-industry ocean-zoning and demonstrates how it can be undertaken within the framework of strategic conservation planning. Copyright © 2015 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.

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
Social strategy games in communicating trade-offs between mitigation and adaptation in cities

DEFF Research Database (Denmark)

Juhola, Sirkku; Driscoll, Patrick Arthur; Suarez, Pablo

2013-01-01

and mitigation strategies and what kinds of negative and positive synergies can be identified between them. This paper explores how social games can help people to understand the trade-offs between mitigation and adaptation measures in an urban environment and examines the possibilities of using social gaming...... as a research method. Data was collected from Denmark, Finland and the US through organized gaming sessions. The conclusion of the study is that social games are a promising method to understand complex planning problems....
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.
Opportunities and trade-offs of biomass based negative emissions within planetary boundaries

Science.gov (United States)

Heck, Vera; Gerten, Dieter; Lucht, Wolfgang

2017-04-01

The Paris Agreement requires "a balance between anthropogenic emissions by sources and removals by sinks of greenhouse gases in the second half of the century" (UNFCCC, 2015). Without a full decarbonization of the energy and land use sector until the second half of this century, negative emission technologies (NETs) are required to achieve net zero greenhouse gas emissions. Integrated assessment studies indicate that bioenergy with carbon capture and storage (BECCS), a land based NET, has the potential to contribute substantially to balancing anthropogenic fossil fuel emissions. However, significant negative emission potentials from BECCS require substantial biomass potentials, which can only be achieved by intensively managed (fertilized and irrigated) large-scale biomass plantations. Additional to direct trade-offs of land and water availability, the implementation of large-scale biomass plantations implies major restructuring of the land surface on top of existing land use and would be accompanied by indirect trade-offs such as changes in moisture and energy fluxes. In the context of the planetary boundaries framework as proposed by Rockström et al. (2009), BECCS might contribute to reduce the transgression of the planetary boundary (PB) for climate change, but would most likely steer the Earth system closer to the PB for freshwater use and lead to further transgression of the PBs for land system change, biosphere integrity and biogeochemical flows. This presentation will investigate the opportunities of second generation biomass potentials within the safe operating space for humanity and highlight the multidimensional trade-offs between biomass potentials for BECCS in relation to the PBs. Scenarios of land availability for biomass plantations and land based carbon sequestration were developed with a spatially explicit multi-criterial optimization framework, considering the precautionary need to stay within the safe operating space vis-à-vis the need to
DECISION USEFULNESS: TRADE-OFF ANTARA RELIABILITY DAN RELEVANCE

Directory of Open Access Journals (Sweden)

AGUS INDRA TENAYA

2007-07-01

Full Text Available 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 predict future value of a firm. This problem couldbe solved by presenting full disclosure of financial statement. Discussion sessionshows that full disclosure results in more useful and reliable accountinginformation to be used in decision making process of various users.
Adhesive bonds for optics: analysis and trade-offs

Science.gov (United States)

Daly, John G.; Hawk, Matthew D.

2017-08-01

Fastening optical elements with adhesives presents challenges when dissimilar materials (almost always the case) are encountered and environmental exposures from temperature changes, shock and vibration must be met. A brief review of standard processes will be followed by a selection criteria for the optic, its substrate, the bond geometry, surface preparation, application and cure. Common analysis practices will be compared to Finite Element models. The impact of stress in terms of distortion and level of risk of bond failure is highlighted. Trade-offs will be presented as aids in determination of the best approach. Some areas addressed will be different adhesive types, matching CTE's, stress effects, athermal bonds, monolithic designs, and the use of flexures.
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.
FINANCIAL PERFORMANCE VERSUS NON FINANCIAL PERFORMANCE. CASE STUDY AT ANTIBIOTICE TRADING COMPANY IASI

Directory of Open Access Journals (Sweden)

BeleneÂºi MÃ£rioara

2012-07-01

Full Text Available The actual economical conditions, the effect of global crisis and the efforts to pass this turning point, does force trading companies toward an extremely balanced management of performance. Now, when financial indicators are neither so spectacular nor so relevant, and when the principles of a durable development are mentioned over and over, the exigencies of companiesâ€™ external environment are higher and higher. This reality does force the companies to pay more attention to social responsibilitiesâ€™ assuming and investment into green innovation, as well as to the field of informationâ€™s communication in a relevant way, which should gather financial, social and environment information. The absence of a normalized balance of financial and non-financial indicators used in measuring companiesâ€™ global performance, does allow them selecting of â€œagreedâ€ indicators which should reflect the company under the light of high performance. But, the same reason urges the searcher for some research studies of the most adequate diagnostic model of global performance, which should faithfully reflect companyâ€™s current status. The purpose of this study is to measure the global performance of ANTIBIOTICE Trading Company, taking into account, both financial and non-financial indicators for a period of 5 years. For the financial years 2006 and 2008 companyâ€™s global performance is an acceptable one, while for the financial years 2007, 2009 and 2010 the global performance is a medium one. It should be highlighted the lack of involvement or transparency regarding social and environment responsibility in 2006 and weak financial performance in 2008, indicators which positioned the company to an acceptable level.
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.
Hybrid Accuracy-Time Trade-off Solution for Spectrum Sensing in Cognitive Radio Networks

DEFF Research Database (Denmark)

Ivanov, Antoni Stefkov; Mihovska, Albena Dimitrova; Poulkov, Vladimir

2018-01-01

parameters, therefore, a suitable trade-off is necessary for an optimal efficiency. We propose a dual-approach solution. The decision about the spectrum occupancy is made using the measured signal-to-noise ratio (SNR) and the received signal levels as inputs in a fuzzy logic algorithm. The result...
Evolution of resistance and tolerance to herbivores: testing the trade-off hypothesis

Directory of Open Access Journals (Sweden)

Eunice Kariñho-Betancourt

2015-03-01

Full Text Available Background. To cope with their natural enemies, plants rely on resistance and tolerance as defensive strategies. Evolution of these strategies among natural population can be constrained by the absence of genetic variation or because of the antagonistic genetic correlation (trade-off between them. Also, since plant defenses are integrated by several traits, it has been suggested that trade-offs might occur between specific defense traits.Methodology/Principal Findings. We experimentally assessed (1 the presence of genetic variance in tolerance, total resistance, and leaf trichome density as specific defense trait, (2 the extent of natural selection acting on plant defenses, and (3 the relationship between total resistance and leaf trichome density with tolerance to herbivory in the annual herb Datura stramonium. Full-sib families of D. stramonium were either exposed to natural herbivores (control or protected from them by a systemic insecticide. We detected genetic variance for leaf trichome density, and directional selection acting on this character. However, we did not detect a negative significant correlation between tolerance and total resistance, or between tolerance and leaf trichome density. We argue that low levels of leaf damage by herbivores precluded the detection of a negative genetic correlation between plant defense strategies.Conclusions/Significance. This study provides empirical evidence of the independent evolution of plant defense strategies, and a defensive role of leaf trichomes. The pattern of selection should favor individuals with high trichomes density. Also, because leaf trichome density reduces damage by herbivores and possess genetic variance in the studied population, its evolution is not constrained.
The effect of klapskate hinge position on push-off performance: a simulation study

OpenAIRE

Houdijk, J.H.P.; Bobbert, M.F.; de Koning, J.J.; de Groot, G.

2003-01-01

Purpose: The introduction of the klapskate in speed skating confronts skaters with the question of how to adjust the position of the hinge in order to maximize performance. The purpose of this study was to reveal the constraint that klapskate hinge position imposes on push-off performance in speed skating. Method: For this purpose, a model of the musculoskeletal system was designed to simulate a simplified, two-dimensional skating push off. To capture the essence of a skating push off, this m...
Industrial-strength ecology: trade-offs and opportunities in algal biofuel production.

Science.gov (United States)

Shurin, Jonathan B; Abbott, Rachel L; Deal, Michael S; Kwan, Garfield T; Litchman, Elena; McBride, Robert C; Mandal, Shovon; Smith, Val H

2013-11-01

Microalgae represent one of the most promising groups of candidate organisms for replacing fossil fuels with contemporary primary production as a renewable source of energy. Algae can produce many times more biomass per unit area than terrestrial crop plants, easing the competing demands for land with food crops and native ecosystems. However, several aspects of algal biology present unique challenges to the industrial-scale aquaculture of photosynthetic microorganisms. These include high susceptibility to invading aquatic consumers and weeds, as well as prodigious requirements for nutrients that may compete with the fertiliser demands of other crops. Most research on algal biofuel technologies approaches these problems from a cellular or genetic perspective, attempting either to engineer or select algal strains with particular traits. However, inherent functional trade-offs may limit the capacity of genetic selection or synthetic biology to simultaneously optimise multiple functional traits for biofuel productivity and resilience. We argue that a community engineering approach that manages microalgal diversity, species composition and environmental conditions may lead to more robust and productive biofuel ecosystems. We review evidence for trade-offs, challenges and opportunities in algal biofuel cultivation with a goal of guiding research towards intensifying bioenergy production using established principles of community and ecosystem ecology. © 2013 John Wiley & Sons Ltd/CNRS.
Balanced the Trade-offs problem of ANFIS Using Particle Swarm Optimisation

Directory of Open Access Journals (Sweden)

Dian Palupi Rini

2013-11-01

Full Text Available Improving the approximation accuracy and interpretability of fuzzy systems is an important issue either in fuzzy systems theory or in its applications . It is known that simultaneous optimisation both issues was the trade-offs problem, but it will improve performance of the system and avoid overtraining of data. Particle swarm optimisation (PSO is part of evolutionary algorithm that is good candidate algorithms to solve multiple optimal solution and better global search space. This paper introduces an integration of PSO dan ANFIS for optimise its learning especially for tuning membership function parameters and finding the optimal rule for better classification. The proposed method has been tested on four standard dataset from UCI machine learning i.e. Iris Flower, Habermans Survival Data, Balloon and Thyroid dataset. The results have shown better classification using the proposed PSO-ANFIS and the time complexity has reduced accordingly.
Informing decision makers and identifying niche opportunities for windpower: use of multiattribute trade off analysis to evaluate non-dispatchable resources

International Nuclear Information System (INIS)

Connors, S.R.

1996-01-01

The operational and flexibility characteristics of renewable energy technologies are often overlooked in traditional head to head technology comparisons. This impedes their adoption since identification of environmental and risk mitigation advantages requires evaluation of such non-dispatchable technologies in a systemwide context. Use of multiattribute resource planning tools in a trade off analysis framework identifies the complementary emissions reduction and fuel diversification characteristics of renewables. Data visualization using trade off analysis communicates electric resource interactions and the risks of following various strategies to diverse stakeholder audiences, promoting acceptance. This paper provides an overview of the multiattribute trade off approach and applies it to resource strategies incorporating windpower in the New England regional power system. Examples focus on the interaction of wind resources with demand-side management and supply-side options under fuel cost uncertainty. (Author)
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
Is there a risk-return trade-off in educational choices? Evidence from Spain

NARCIS (Netherlands)

Díaz-Serrano, L.; Hartog, J.

2006-01-01

We use data from Spain to test for an effect of earnings variance and skewness on individual wages. We carry out separate estimations for men and women. In accordance with the scant previous evidence mainly focused on the US, we report the existence of a risk-return trade-off across educational
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....
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

Urban and agricultural soils: conflicts and trade-offs in the optimization of ecosystem services

NARCIS (Netherlands)

Setälä, H.; Bardgett, R.D.; Birkhofer, K.; Brady, M.; Byrne, L.; de Ruiter, P.C.; de Vries, F.T.; Gardi, C.; Hedlund, K.; Hemerik, L.; Hotes, S.; Liiri, M.; Mortimer, S.R.; Pavao-Zuckerman, M.; Pouyat, R.; Tsiafouli, M.; Van der Putten, W.H.

2014-01-01

[KEYWORDS: Agriculture Ecosystem services Land use Management optimization Soil Urban Trade-off] On-going human population growth and changing patterns of resource consumption are increasing global demand for ecosystem services, many of which are provided by soils. Some of these ecosystem services
Trade-off coding for universal qudit cloners motivated by the Unruh effect

International Nuclear Information System (INIS)

Jochym-O'Connor, Tomas; Bradler, Kamil; Wilde, Mark M

2011-01-01

A 'triple trade-off' capacity region of a noisy quantum channel provides a more complete description of its capabilities than does a single capacity formula. However, few full descriptions of a channel's ability have been given due to the difficult nature of the calculation of such regions-it may demand an optimization of information-theoretic quantities over an infinite number of channel uses. This work analyses the d-dimensional Unruh channel, a noisy quantum channel which emerges in relativistic quantum information theory. We show that this channel belongs to the class of quantum channels whose capacity region requires an optimization over a single channel use, and as such is tractable. We determine two triple-trade off regions, the quantum dynamic capacity region and the private dynamic capacity region, of the d-dimensional Unruh channel. Our results show that the set of achievable rate triples using this coding strategy is larger than the set achieved using a time-sharing strategy. Furthermore, we prove that the Unruh channel has a distinct structure made up of universal qudit cloning channels, thus providing a clear relationship between this relativistic channel and the process of stimulated emission present in quantum optical amplifiers. (paper)
Outage Probability versus Fairness Trade-off in Opportunistic Relay Selection with Outdated CSI

Directory of Open Access Journals (Sweden)

Vicario JoseLopez

2009-01-01

Full Text Available We analyze the existing trade-offs in terms of system performance versus fairness of a cooperative system based on opportunistic relay selection (ORS and with outdated channel state information (CSI. In particular, system performance is analytically evaluated in terms of outage probability, and the fairness behavior is assessed based on the power consumption at the different relays. In order to improve the fairness behavior of ORS while keeping the selection diversity gain, we propose a relay selection mechanism where the relay with the highest normalized signal-to-noise ratio (SNR is selected for relaying the source's information. The proposed strategy is compared with existing relay selection strategies by adopting a novel graphical representation inspired by expected profit versus risk plots used in modern portfolio theory. As shown in the paper, this strategy allows operating the system in more favorable points of the outage versus fairness region.
Limited Cognitive Resources Explain a Trade-Off between Perceptual and Metacognitive Vigilance.

Science.gov (United States)

Maniscalco, Brian; McCurdy, Li Yan; Odegaard, Brian; Lau, Hakwan

2017-02-01

Why do experimenters give subjects short breaks in long behavioral experiments? Whereas previous studies suggest it is difficult to maintain attention and vigilance over long periods of time, it is unclear precisely what mechanisms benefit from rest after short experimental blocks. Here, we evaluate decline in both perceptual performance and metacognitive sensitivity (i.e., how well confidence ratings track perceptual decision accuracy) over time and investigate whether characteristics of prefrontal cortical areas correlate with these measures. Whereas a single-process signal detection model predicts that these two forms of fatigue should be strongly positively correlated, a dual-process model predicts that rates of decline may dissociate. Here, we show that these measures consistently exhibited negative or near-zero correlations, as if engaged in a trade-off relationship, suggesting that different mechanisms contribute to perceptual and metacognitive decisions. Despite this dissociation, the two mechanisms likely depend on common resources, which could explain their trade-off relationship. Based on structural MRI brain images of individual human subjects, we assessed gray matter volume in the frontal polar area, a region that has been linked to visual metacognition. Variability of frontal polar volume correlated with individual differences in behavior, indicating the region may play a role in supplying common resources for both perceptual and metacognitive vigilance. Additional experiments revealed that reduced metacognitive demand led to superior perceptual vigilance, providing further support for this hypothesis. Overall, results indicate that during breaks between short blocks, it is the higher-level perceptual decision mechanisms, rather than lower-level sensory machinery, that benefit most from rest. Perceptual task performance declines over time (the so-called vigilance decrement), but the relationship between vigilance in perception and metacognition has
Active rc filter permits easy trade-off of amplifier gain and sensitivity to gain

Science.gov (United States)

Kerwin, W. J.; Shaffer, C. V.

1968-01-01

Passive RC network was designed with zeros of transmission in the right half of the complex frequency plane in the feedback loop of a simple negative-gain amplifier. The proper positioning provides any desired trade-off between amplifier gain and sensitivity to amplifier gain.
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.
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....
Modelling the Volatility-Return Trade-off when Volatility may be Nonstationary

DEFF Research Database (Denmark)

Dahl, Christian Møller; Iglesias, Emma M.

In this paper a new GARCH-M type model, denoted the GARCH-AR, is proposed. In particular, it is shown that it is possible to generate a volatility-return trade-off in a regression model simply by introducing dynamics in the standardized disturbance process. Importantly, the volatility in the GARCH......, we provide an empirical illustration showing the empirical relevance of the GARCH-AR model based on modelling a wide range of leading US stock return series....
Navigating trade-offs in land-use planning: integrating human well-being into objective setting

Directory of Open Access Journals (Sweden)

Vanessa M. Adams

2014-12-01

Full Text Available There is an increasing demand for development of natural resources, which can be accompanied by environmental degradation. Planning for multiple land uses requires navigating trade-offs between social, economic, and environmental outcomes arising from different possible futures. To explore these trade-offs, we use the Daly River catchment, in Australia's Northern Territory, as a case study. The catchment contains areas of priority for both conservation and development. In response to the challenge of navigating the required trade-offs, the Daly River Management Advisory Committee (DRMAC initiated a land-use plan for the region. Both development and conservation of natural resources in the catchment will affect human well-being and the long-term provisioning of ecosystem services in diverse ways. To understand some of these impacts, an innovative engagement process was designed to elicit the relative importance of key factors to residents' well-being. The process identified 19 well-being factors grouped into four domains: biodiversity, socio-cultural, recreational, and commercial. Overall, the highest-ranked well-being factors were in the social-cultural and biodiversity domains while commercial values were ranked the least important. Respondents reported low satisfaction with commercial factors as well, noting concerns over environmental impacts from existing developments and sustainability of future developments. We identified differences in the reported importance values for several types of stakeholders, most notably between indigenous respondents and those employed in the agricultural sectors. Indigenous respondents placed greater importance on biodiversity and socio-cultural factors. Agricultural respondents placed greater importance on commercial factors. The outcomes of our engagement were integrated into DRMAC's process of objective-setting to ensure that objectives for each domain were included in land-use planning. Our results can also
Option trading and individual investor performance

NARCIS (Netherlands)

Bauer, R.; Cosemans, M.; Eichholtz, P.

2009-01-01

This paper examines the impact of option trading on individual investor performance. The results show that most investors incur substantial losses on their option investments, which are much larger than the losses from equity trading. We attribute the detrimental impact of option trading on investor
Adaptively evolved yeast mutants on galactose show trade-offs in carbon utilization on glucose

DEFF Research Database (Denmark)

Hong, Kuk-Ki; Nielsen, Jens

2013-01-01

the molecular mechanisms. In this study, adaptively evolved yeast mutants with improved galactose utilization ability showed impaired glucose utilization. The molecular genetic basis of this trade-off was investigated using a systems biology approach. Transcriptional and metabolic changes resulting from...... the improvement of galactose utilization were found maintained during growth on glucose. Moreover, glucose repression related genes showed conserved expression patterns during growth on both sugars. Mutations in the RAS2 gene that were identified as beneficial for galactose utilization in evolved mutants...
Testing the carotenoid trade-off hypothesis in the polychromatic Midas cichlid, Amphilophus citrinellus.

Science.gov (United States)

Lin, Susan M; Nieves-Puigdoller, Katherine; Brown, Alexandria C; McGraw, Kevin J; Clotfelter, Ethan D

2010-01-01

Many animals use carotenoid pigments derived from their diet for coloration and immunity. The carotenoid trade-off hypothesis predicts that, under conditions of carotenoid scarcity, individuals may be forced to allocate limited carotenoids to either coloration or immunity. In polychromatic species, the pattern of allocation may differ among individuals. We tested the carotenoid trade-off hypothesis in the Midas cichlid, Amphilophus citrinellus, a species with two ontogenetic color morphs, barred and gold, the latter of which is the result of carotenoid expression. We performed a diet-supplementation experiment in which cichlids of both color morphs were assigned to one of two diet treatments that differed only in carotenoid content (beta-carotene, lutein, and zeaxanthin). We measured integument color using spectrometry, quantified carotenoid concentrations in tissue and plasma, and assessed innate immunity using lysozyme activity and alternative complement pathway assays. In both color morphs, dietary carotenoid supplementation elevated plasma carotenoid circulation but failed to affect skin coloration. Consistent with observable differences in integument coloration, we found that gold fish sequestered more carotenoids in skin tissue than barred fish, but barred fish had higher concentrations of carotenoids in plasma than gold fish. Neither measure of innate immunity differed between gold and barred fish, or as a function of dietary carotenoid supplementation. Lysozyme activity, but not complement activity, was strongly affected by body condition. Our data show that a diet low in carotenoids is sufficient to maintain both coloration and innate immunity in Midas cichlids. Our data also suggest that the developmental transition from the barred to gold morph is not accompanied by a decrease in innate immunity in this species.
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.
Local above-ground persistence of vascular plants : Life-history trade-offs and environmental constraints

NARCIS (Netherlands)

Ozinga, Wim A.; Hennekens, Stephan M.; Schaminee, Joop H. J.; Smits, Nina A. C.; Bekker, Renee M.; Roemermann, Christine; Klimes, Leos; Bakker, Jan P.; van Groenendael, Jan M.

Questions: 1. Which plant traits and habitat characteristics best explain local above-ground persistence of vascular plant species and 2. Is there a trade-off between local above-ground persistence and the ability for seed dispersal and below-ground persistence in the soil seed bank? Locations: 845
Seed size-number trade-off in Euterpe edulis in plant communities of the Atlantic Forest

Directory of Open Access Journals (Sweden)

Pedro Henrique Santin Brancalion

2014-06-01

Full Text Available Investigations of seed size and number differences among plant populations growing in contrasting habitats can provide relevant information about ecological strategies that optimize reproductive effort. This may imply important consequences for biodiversity conservation and restoration. Therefore, we sought to investigate seed size-number trade-off in Euterpe edulis populations growing in plant communities in the Brazilian Atlantic Forest. Seed dry mass and seed number per bunch were evaluated in 2008 and 2009 in large remnants of the Seasonally Dry Forest, Restinga Forest and Atlantic Rainforest in southeastern Brazil, in 20 individuals per site and year. Seed size and seed number varied among forest types, but a seed size-number trade-off was neither observed within nor among populations. Positive association between seed size and number was found in the Atlantic Rainforest, and reduced seed crop was not accompanied by heavier seeds in the Restinga Forest. Seed dry mass declined in 2009 in all three forest types. Compared to seed number in 2008, palms of both the Restinga Forest and the Atlantic Rainforest produced in 2009 higher yields of smaller seeds - evidence of between years seed size-number trade-off -, while the Seasonally Dry Forest population produced a reduced number of smaller seeds. Such a flexible reproductive strategy, involving neutral, positive, and negative associations between seed size and number could enhance the ecological amplitude of this species and their potential to adapt to different environment conditions.
Constant versus variable response signal delays in speed--accuracy trade-offs: effects of advance preparation for processing time.

Science.gov (United States)

Miller, Jeff; Sproesser, Gudrun; Ulrich, Rolf

2008-07-01

In two experiments, we used response signals (RSs) to control processing time and trace out speed--accuracy trade-off(SAT) functions in a difficult perceptual discrimination task. Each experiment compared performance in blocks of trials with constant and, hence, temporally predictable RS lags against performance in blocks with variable, unpredictable RS lags. In both experiments, essentially equivalent SAT functions were observed with constant and variable RS lags. We conclude that there is little effect of advance preparation for a given processing time, suggesting that the discrimination mechanisms underlying SAT functions are driven solely by bottom-up information processing in perceptual discrimination tasks.
Potential Trade-Offs between the Sustainable Development Goals in Coastal Bangladesh

Directory of Open Access Journals (Sweden)

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.
On the generation of coastline-following grids for ocean models—trade-off between orthogonality and alignment to coastlines

Science.gov (United States)

Liu, Xiaonan; Ma, Jialiang; Xu, Shiming; Wang, Bin

2017-08-01

Regional ocean models usually utilize orthogonal curvilinear grids that are fit to the coastline of the modeled regions. While the orthogonality of the grid is required from the perspective of the numerical algorithms, the alignment to the irregular coastlines improves the characterization of the land-sea distribution and the ocean simulation. In this article, we carry out fractal analysis of two representative coastal regions and discuss the trade-offs between the orthogonality and coastline alignment during the grid generation of these regions. A new grid generation method based on Schwarz-Christoffel conformal mappings is proposed, with automatic coastal boundary retrieval algorithm that generates resolution dependent boundary for grid generation and alleviates the human efforts involved in traditional methods. We show that for the southeastern Pacific region, the coastline is smooth with low fractal dimension and there exists effective trade-off with a coastline boundary that adjusts to the desired grid resolution. On the contrary, there is no effective trade-off for southeast China seas where the coastline is of higher fractal dimension, and a coarser coastline boundary is recommended for better orthogonality with little loss in coastline alignment. Further numerical study of coastal trapped Kelvin waves for the typical regions demonstrate that the new coastline-fitting grids achieve smaller error in numerical dispersion and higher accuracy. Through analysis, we conclude that for grid generation for regional ocean modeling, modelers should bring into consideration of the multi-scale fractal characteristics of the coastline.
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...

Trade-off between angular and spatial resolutions in in vivo fiber tractography

OpenAIRE

Vos, Sjoerd B.; Aksoy, Murat; Han, Zhaoying; Holdsworth, Samantha J.; Maclaren, Julian; Viergever, Max A.; Leemans, Alexander; Bammer, Roland

2016-01-01

Tractography is becoming an increasingly popular method to reconstruct white matter connections in vivo. The diffusion MRI data that tractography is based on requires a high angular resolution to resolve crossing fibers whereas high spatial resolution is required to distinguish kissing from crossing fibers. However, scan time increases with increasing spatial and angular resolutions, which can become infeasible in clinical settings. Here we investigated the trade-off between spatial and angul...
Trade-offs Between Electricity Production from Small Hydropower Plants and Ecosystem Services in Alpine River Basins

Science.gov (United States)

Meier, Philipp; Schwemmle, Robin; Viviroli, Daniel

2015-04-01

The need for a reduction in greenhouse gas emissions and the decision to phase out nuclear power plants in Switzerland and Germany increases pressure to develop the remaining hydropower potential in Alpine catchments. Since most of the potential for large reservoirs is already exploited, future development focusses on small run-of-the-river hydropower plants (SHP). Being considered a relatively environment-friendly electricity source, investment in SHP is promoted through subsidies. However, SHP can have a significant impact on riverine ecosystems, especially in the Alpine region where residual flow reaches tend to be long. An increase in hydropower exploitation will therefore increase pressure on ecosystems. While a number of studies assessed the potential for hydropower development in the Alps, two main factors were so far not assessed in detail: (i) ecological impacts within a whole river network, and (ii) economic conditions under which electricity is sold. We present a framework that establishes trade-offs between multiple objectives regarding environmental impacts, electricity production and economic evaluation. While it is inevitable that some ecosystems are compromised by hydropower plants, the context of these impacts within a river network should be considered when selecting suitable sites for SHP. From an ecological point of view, the diversity of habitats, and therefore the diversity of species, should be maintained within a river basin. This asks for objectives that go beyond lumped parameters of hydrological alteration, but also consider habitat diversity and the spatial configuration. Energy production in run-of-the-river power plants depends on available discharge, which can have large fluctuations. In a deregulated electricity market with strong price variations, an economic valuation should therefore be based on the expected market value of energy produced. Trade-off curves between different objectives can help decision makers to define policies
Diversity-Multiplexing Trade-off for Coordinated Direct and Relay Schemes

DEFF Research Database (Denmark)

Thai, Chan; Popovski, Petar; De Carvalho, Elisabeth

2013-01-01

The recent years have brought a significant body of research on wireless Two-Way Relaying (TWR), where the use of network coding brings an evident advantage in terms of data rates. Yet, TWR scenarios represent only a special case and it is of interest to devise similar techniques in more general...... Direct/Relay (CDR) schemes, which involve two flows, of a direct and a relayed user. In this paper we characterize a CDR scheme by deriving/bounding the Diversity-Multiplexing Trade-off (DMT) function. Two cases are considered. In the first case a transmitter knows the Channel State Information (CSI...
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.
Life-history strategies of North American elk: trade-offs associated with reproduction and survival

Science.gov (United States)

Sabrina Morano; Kelley M. Stewart; James S. Sedinger; Christopher A. Nicolai; Marty Vavra

2013-01-01

The principle of energy allocation states that individuals should attempt to maximize fitness by allocating resources optimally among growth, maintenance, and reproduction. Such allocation may result in trade-offs between survival and reproduction, or between current and future reproduction. We used a marked population of North American elk (Cervus elaphus...
Individual heterogeneity and offspring sex affect the growth-reproduction trade-off in a mammal with indeterminate growth.

Science.gov (United States)

Gélin, Uriel; Wilson, Michelle E; Cripps, Jemma; Coulson, Graeme; Festa-Bianchet, Marco

2016-04-01

Reproduction can lead to a trade-off with growth, particularly when individuals reproduce before completing body growth. Kangaroos have indeterminate growth and may always face this trade-off. We combined an experimental manipulation of reproductive effort and multi-year monitoring of a large sample size of marked individuals in two populations of eastern grey kangaroos to test the predictions (1) that reproduction decreases skeletal growth and mass gain and (2) that mass loss leads to reproductive failure. We also tested if sex-allocation strategies influenced these trade-offs. Experimental reproductive suppression revealed negative effects of reproduction on mass gain and leg growth from 1 year to the next. Unmanipulated females, however, showed a positive correlation between number of days lactating and leg growth over periods of 2 years and longer, suggesting that over the long term, reproductive costs were masked by individual heterogeneity in resource acquisition. Mass gain was necessary for reproductive success the subsequent year. Although mothers of daughters generally lost more mass than females nursing sons, mothers in poor condition experienced greater mass gain and arm growth if they had daughters than if they had sons. The strong links between individual mass changes and reproduction suggest that reproductive tactics are strongly resource-dependent.
Trade-off coding for universal qudit cloners motivated by the Unruh effect

Energy Technology Data Exchange (ETDEWEB)

Jochym-O' Connor, Tomas [Department of Physics and Astronomy, Institute for Quantum Computing, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2 L 3G1 (Canada); Bradler, Kamil; Wilde, Mark M, E-mail: trjochym@uwaterloo.ca [School of Computer Science, McGill University, Montreal, Quebec H3A 2A7 (Canada)

2011-10-14

A 'triple trade-off' capacity region of a noisy quantum channel provides a more complete description of its capabilities than does a single capacity formula. However, few full descriptions of a channel's ability have been given due to the difficult nature of the calculation of such regions-it may demand an optimization of information-theoretic quantities over an infinite number of channel uses. This work analyses the d-dimensional Unruh channel, a noisy quantum channel which emerges in relativistic quantum information theory. We show that this channel belongs to the class of quantum channels whose capacity region requires an optimization over a single channel use, and as such is tractable. We determine two triple-trade off regions, the quantum dynamic capacity region and the private dynamic capacity region, of the d-dimensional Unruh channel. Our results show that the set of achievable rate triples using this coding strategy is larger than the set achieved using a time-sharing strategy. Furthermore, we prove that the Unruh channel has a distinct structure made up of universal qudit cloning channels, thus providing a clear relationship between this relativistic channel and the process of stimulated emission present in quantum optical amplifiers. (paper)
Neutral genetic variation in adult Chinook salmon (Oncorhynchus tshawytscha) affects brain-to-body trade-off and brain laterality

Science.gov (United States)

Heath, Daniel D.; Higgs, Dennis M.

2017-01-01

Low levels of heterozygosity can have detrimental effects on life history and growth characteristics of organisms but more subtle effects such as those on trade-offs of expensive tissues and morphological laterality, especially of the brain, have not been explicitly tested. The objective of the current study was to investigate how estimated differences in heterozygosity may potentially affect brain-to-body trade-offs and to explore how these heterozygosity differences may affect differential brain growth, focusing on directional asymmetry in adult Chinook salmon (Oncorhynchus tshawytscha) using the laterality and absolute laterality indices. Level of inbreeding was estimated as mean microsatellite heterozygosity resulting in four ‘inbreeding level groups’ (Very High, High, Medium, Low). A higher inbreeding level corresponded with a decreased brain-to-body ratio, thus a decrease in investment in brain tissue, and also showed a decrease in the laterality index for the cerebellum, where the left hemisphere was larger than the right across all groups. These results begin to show the role that differences in heterozygosity may play in differential tissue investment and in morphological laterality, and may be useful in two ways. Firstly, the results may be valuable for restocking programmes that wish to emphasize brain or body growth when crossing adults to generate individuals for release, as we show that genetic variation does affect these trade-offs. Secondly, this study is one of the first examinations to test the hypothesized relationship between genetic variation and laterality, finding that in Chinook salmon there is potential for an effect of inbreeding on lateralized morphology, but not in the expected direction. PMID:29308240
Is Equality always desirable? : Analyzing the Trade-Off between Fairness and Attractiveness in Crew Rostering

NARCIS (Netherlands)

T. Breugem (Thomas); T.A.B. Dollevoet (Twan); D. Huisman (Dennis)

2017-01-01

textabstractIn this paper, we analyze the trade-off between perceived fairness and perceived attractiveness in crew rostering. First, we introduce the Fairness-oriented Crew Rostering Problem. In this problem, attractive cyclic rosters have to be constructed, while respecting a pre-specified
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.
The quantity-quality trade-off of children in a developing country: identification using Chinese twins.

Science.gov (United States)

Li, Hongbin; Zhang, Junsen; Zhu, Yi

2008-02-01

Testing the trade-off between child quantity and quality within a family is complicated by the endogeneity of family size. Using data from the Chinese Population Census, we examine the effect of family size on child educational attainment in China. We find a negative correlation between family size and child outcome, even after we control for the birth order effect. We then instrument family size by the exogenous variation that is induced by a twin birth and find a negative effect offamily size on children's education. We also find that the effect of family size is more evident in rural China, where the public education system is poor. Given that our estimates of the effect of having twins on nontwins at least provide the lower bound of the true effect of family size, these findings suggest a quantity-quality trade-off for children in developing countries.
Is there a Risk-Return Trade-off across Occupations? Evidence from Spain

OpenAIRE

Luis Diaz-Serrano; J. Hartog

2004-01-01

We use data from Spain to test for an effect of earnings risk and skewness on individual wages. We carry out separate estimation for men, women, public and private sector employees. In accordance with previous evidence for the US we show the existence of a risk-return trade-off across occupations in the Spanish labour market. These results are in conformity with preferences of risk-averse individuals with decreasing absolute risk aversion.
Compact and resource efficient cities? Synergies and trade-offs in European cities

DEFF Research Database (Denmark)

Fertner, Christian; Große, Juliane

2016-01-01

city. Compact cities and compact urban development are thought to decrease energy and resource demand per capita and increase efficiency. At the same time trade-offs and potential rebound effects of increased resource efficiency question certain achievements of a dense urban structure. This paper...... alternative travel modes. Also the allocation of efficiency gains due to compact urban development has to be taken into account in order to avoid direct and indirect rebound effects....
Reversing the picture superiority effect: a speed-accuracy trade-off study of recognition memory.

Science.gov (United States)

Boldini, Angela; Russo, Riccardo; Punia, Sahiba; Avons, S E

2007-01-01

Speed-accuracy trade-off methods have been used to contrast single- and dual-process accounts of recognition memory. With these procedures, subjects are presented with individual test items and required to make recognition decisions under various time constraints. In three experiments, we presented words and pictures to be intentionally learned; test stimuli were always visually presented words. At test, we manipulated the interval between the presentation of each test stimulus and that of a response signal, thus controlling the amount of time available to retrieve target information. The standard picture superiority effect was significant in long response deadline conditions (i.e., > or = 2,000 msec). Conversely, a significant reverse picture superiority effect emerged at short response-signal deadlines (< 200 msec). The results are congruent with views suggesting that both fast familiarity and slower recollection processes contribute to recognition memory. Alternative accounts are also discussed.
Invasion versus isolation: Trade-offs in managing native salmonids with barriers to upstream movement

Science.gov (United States)

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

2009-01-01

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...
Early and extraordinary peaks in physical performance come with a longevity cost

DEFF Research Database (Denmark)

van de Vijver, Paul L; van Bodegom, David; Westendorp, Rudi G J

2016-01-01

Life history theory postulates a trade-off between development and maintenance. This trade-off is observed when comparing life histories of different animal species. In humans, however, it is debated if variation in longevity is explained by differences in developmental traits. Observational...... studies found a trade-off between early and high fecundity and longevity in women. Development encompasses more than fecundity and also concerns growth and physical performance. Here, we show a life history trade-off between early and above average physical performance and longevity in male Olympic...... suffered a 4.7-year longevity cost. (95% CI 2.1-7.5 years, p=0.001). This is the first time a life history trade-off between physical performance and longevity has been found in humans. This finding deepens our understanding of early developmental influences on the variation of longevity in humans....
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
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
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
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.

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...
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.
The effects of klapskate hinge position on push-off performance: a simulation study.

Science.gov (United States)

Houdijk, Han; Bobbert, Maarten F; De Koning, Jos J; De Groot, Gert

2003-12-01

The introduction of the klapskate in speed skating confronts skaters with the question of how to adjust the position of the hinge in order to maximize performance. The purpose of this study was to reveal the constraint that klapskate hinge position imposes on push-off performance in speed skating. For this purpose, a model of the musculoskeletal system was designed to simulate a simplified, two-dimensional skating push off. To capture the essence of a skating push off, this model performed a one-leg vertical jump, from a frictionless surface, while keeping its trunk horizontally. In this model, klapskate hinge position was varied by varying the length of the foot segment between 115 and 300 mm. With each foot length, an optimal control solution was found that resulted in the maximal amount of vertical kinetic and potential energy of the body's center of mass at take off (Weff). Foot length was shown to considerably affect push-off performance. Maximal Weff was obtained with a foot length of 185 mm and decreased by approximately 25% at either foot length of 115 mm and 300 mm. The reason for this decrease was that foot length affected the onset and control of foot rotation. This resulted in a distortion of the pattern of leg segment rotations and affected muscle work (Wmus) and the efficacy ratio (Weff/Wmus) of the entire leg system. Despite its simplicity, the model very well described and explained the effects of klapskate hinge position on push off performance that have been observed in speed-skating experiments. The simplicity of the model, however, does not allow quantitative analyses of optimal klapskate hinge position for speed-skating practice.
Incubation temperature influences trade-off between structural size and energy reserves in mallard hatchlings

Czech Academy of Sciences Publication Activity Database

Koláčková, M.; Prokůpková, L.; Albrecht, Tomáš; Hořák, D.

2015-01-01

Roč. 88, č. 1 (2015), s. 1-10 ISSN 1522-2152 R&D Projects: GA AV ČR KJB601110803 Institutional support: RVO:68081766 Keywords : body mass * chemical composition * hatching * incubation * parent-offspring interaction * parental investment * phenotype * reproductive success * reptile * survival * temperature effect * trade-off * waterfowl Subject RIV: EG - Zoology Impact factor: 2.007, year: 2015
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....
Integrating ecosystem services trade-offs with paddy land-to-dry land decisions: A scenario approach in Erhai Lake Basin, southwest China.

Science.gov (United States)

Hu, Yi'na; Peng, Jian; Liu, Yanxu; Tian, Lu

2018-06-01

Ecosystem services are the benefits people obtain from ecosystems, and ecosystem services trade-offs have been widely applied to the development of land-use policy. Although previous studies have focused on trade-offs of ecosystem services, a scenario approach has been seldom used. The scenario approach can reveal the changes of ecosystem services for different land-use patterns in the future, and is of great significance for land-use decisions and ecosystem management. Based on the actual situation of deteriorating water quality and dwindling water supply in the Erhai Lake Basin of southwest China, this study put forward to convert paddy land to dry land (PLDL) in the basin, and simulated its potential impact on ecosystem services. Taking environmental pollution, social impact, economic benefit and residential participation into consideration, four scenarios of PLDL were designed. Then, four ecosystem services (water purification, water yield, soil conservation and rice production) were calculated for each scenario. The optimal scenario of PLDL in the Erhai Lake Basin was identified by trade-offs of the four ecosystem services. The results showed that the total nitrogen export could be reduced by 42.07% and water yield can be increased by 5.61% after converting 100% of paddy lands to dry land, thereby greatly improving the water quality and increasing the water yield of Erhai Lake. However, PLDL involving 100% of paddy lands also increased the sediment export by 17.22%, and eliminated rice production in the region. By comparing the four PLDL scenarios for converting just 50% of paddy lands, the residential participation scenario was identified to be the best choice for PLDL implementation because it achieved the best level of water purification and had the smallest negative effect on other ecosystem services. The optimal scenario for each township showed spatial differentiation, and there were conflicts between the optimal scenarios at basin scale and township
Perfluoropolyether-Impregnated Mesoporous Alumina Composites Overcome the Dewetting-Tribological Properties Trade-Off.

Science.gov (United States)

Rowthu, Sriharitha; Hoffmann, Patrik

2018-03-28

Conventional omniphobic surfaces suffer from wear-sensitivity due to soft apolar coatings or substrates and protruding surface features that are eroded even for mild abrasion treatments, leading to the loss of dewetting properties after wear. Evidently, there was a trade-off between dewetting and tribological properties. Here, we show the establishment of self-healing slippery properties post severe abrasion by utilizing perfluoropolyether-impregnated mesoporous Al 2 O 3 (MPA) composites. The hard polar alumina matrix provides the optimal tribological properties, and the liquid lubricant in the porous network contributes to both tribological and self-healing dewetting properties. These composites sustained normal pressures up to 350 MPa during reciprocating sliding contacts. The severely abraded surfaces are capable of self-replenishing in ambient environment, driven by capillarity and surface diffusion processes, and regained their slippery properties toward water and hexadecane after 15 h of self-healing. Eventually, a dewetting-tribology diagram has been introduced to show different regimes, namely-optimal slippery properties, optimal tribological properties, and a mixed regime). We found out that the microstructural expression [Formula: see text] is a robust guiding tool to predict the regime of interest. This dewetting-tribological diagram may be marked as an inception to designing abrasion-resistant slippery liquid impregnated composites for overcoming the dewetting tribological properties trade-off. Such surfaces may potentially find applications in paint industries and as anti-icing surfaces.
Drivers, constraints and trade-offs associated with recultivating abandoned cropland in Russia, Ukraine and Kazakhstan

DEFF Research Database (Denmark)

Meyfroidt, Patrick; Schierhorn, Florian; Prishchepov, Alexander

2016-01-01

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...... and institutional support could foster recultivation by supporting investments in agriculture and rural demographic revitalization. Reclaiming potentially available cropland in the study region could provide a notable contribution to global grain production, with relatively low environmental trade-offs compared...
The Trade-Off between Female Fertility and Longevity during the Epidemiological Transition in the Netherlands

DEFF Research Database (Denmark)

Kaptijn, Ralf; Thomese, Fleur; Liefbroer, Aart C

2015-01-01

as an evolutionary trade-off between reproduction and survival. We examine the relationship between fertility and longevity during the epidemiological transition in the Netherlands. This period of rapid decline in mortality from infectious diseases offers a good opportunity to study the relationship between...... fertility and longevity, using registry data from 6,359 women born in The Netherlands between 1850 and 1910. We hypothesize that an initially negative relationship between women's fertility and their longevity gradually turns less negative during the epidemiological transition, because of decreasing costs...
Global economic trade-offs between wild nature and tropical agriculture.

Science.gov (United States)

Carrasco, Luis R; Webb, Edward L; Symes, William S; Koh, Lian P; Sodhi, Navjot S

2017-07-01

Global demands for agricultural and forestry products provide economic incentives for deforestation across the tropics. Much of this deforestation occurs with a lack of information on the spatial distribution of benefits and costs of deforestation. To inform global sustainable land-use policies, we combine geographic information systems (GIS) with a meta-analysis of ecosystem services (ES) studies to perform a spatially explicit analysis of the trade-offs between agricultural benefits, carbon emissions, and losses of multiple ecosystem services because of tropical deforestation from 2000 to 2012. Even though the value of ecosystem services presents large inherent uncertainties, we find a pattern supporting the argument that the externalities of destroying tropical forests are greater than the current direct economic benefits derived from agriculture in all cases bar one: when yield and rent potentials of high-value crops could be realized in the future. Our analysis identifies the Atlantic Forest, areas around the Gulf of Guinea, and Thailand as areas where agricultural conversion appears economically efficient, indicating a major impediment to the long-term financial sustainability of Reducing Emissions from Deforestation and forest Degradation (REDD+) schemes in those countries. By contrast, Latin America, insular Southeast Asia, and Madagascar present areas with low agricultural rents (ARs) and high values in carbon stocks and ES, suggesting that they are economically viable conservation targets. Our study helps identify optimal areas for conservation and agriculture together with their associated uncertainties, which could enhance the efficiency and sustainability of pantropical land-use policies and help direct future research efforts.
#eVALUate: Monetizing Service Acquisition Trade-offs Using the QUALITY-INFUSED Price Methodology

Science.gov (United States)

2016-04-01

they determine their source selection methodology along the best-value spectrum, ranging from lowest price technically acceptable (LPTA) to full...sidering factors determined to be germane to service value to the agency (Finkenstadt, 2015). Once an offeror’s prices are determined to be fair and... determine whether the quality rating system would affect the quality trade-off. In this case, the highest priced yet highest rated offeror was selected
Capacity Versus Bit Error Rate Trade-Off in the DVB-S2 Forward Link

Directory of Open Access Journals (Sweden)

Berioli Matteo

2007-01-01

Full Text Available The paper presents an approach to optimize the use of satellite capacity in DVB-S2 forward links. By reducing the so-called safety margins, in the adaptive coding and modulation technique, it is possible to increase the spectral efficiency at expenses of an increased BER on the transmission. The work shows how a system can be tuned to operate at different degrees of this trade-off, and also the performance which can be achieved in terms of BER/PER, spectral efficiency, and interarrival, duration, strength of the error bursts. The paper also describes how a Markov chain can be used to model the ModCod transitions in a DVB-S2 system, and it presents results for the calculation of the transition probabilities in two cases.
Capacity Versus Bit Error Rate Trade-Off in the DVB-S2 Forward Link

Directory of Open Access Journals (Sweden)

Matteo Berioli

2007-05-01

Full Text Available The paper presents an approach to optimize the use of satellite capacity in DVB-S2 forward links. By reducing the so-called safety margins, in the adaptive coding and modulation technique, it is possible to increase the spectral efficiency at expenses of an increased BER on the transmission. The work shows how a system can be tuned to operate at different degrees of this trade-off, and also the performance which can be achieved in terms of BER/PER, spectral efficiency, and interarrival, duration, strength of the error bursts. The paper also describes how a Markov chain can be used to model the ModCod transitions in a DVB-S2 system, and it presents results for the calculation of the transition probabilities in two cases.
Biophysical and sociocultural factors underlying spatial trade-offs of ecosystem services in semiarid watersheds

Directory of Open Access Journals (Sweden)

Marina García-Llorente

2015-09-01

Full Text Available Biophysical and social systems are linked to form social-ecological systems whose sustainability depends on their capacity to absorb uncertainty and cope with disturbances. In this study, we explored the key biophysical and socio-cultural factors underlying ecosystem service supply in two semiarid watersheds of southern Spain. These included variables associated with the role that freshwater flows and biodiversity play in securing the system's capacity to sustain essential ecosystem services and their relationship with social demand for services, local water governance, and land-use intensification. Our results reveal the importance of considering the invisible dimensions of water and biodiversity, i.e. green freshwater flows and trait-based indicators, because of their relevance to the supply of ecosystem services. Furthermore, they uncover the importance of traditional irrigation canals, a local water governance system, in maintaining the ecosystems' capacity to supply services. The study also highlights the complex trade-offs that occur because of the spatial mismatch between ecosystem service supply (upstream and ecosystem service demand (downstream in watersheds. Finally, we found that land-use intensification generally resulted in losses of the biophysical factors that underpin the supply of some ecosystem services, increases in social demand for less diversified services, and the abandonment of local governance practices. Attempts to manage social-ecological systems toward sustainability at the local scale should identify the key biophysical and socio-cultural factors that are essential for maintaining ecosystem services and should recognize existing interrelationships between them. Land-use management should also take into account ecosystem service trade-offs and the consequences resulting from land-use intensification.
Nest site selection by Kentish plover suggests a trade-off between nest-crypsis and predator detection strategies.

Directory of Open Access Journals (Sweden)

Miguel Ángel Gómez-Serrano

Full Text Available Predation is one of the main causes of adult mortality and breeding failure for ground-nesting birds. Micro-habitat structure around nests plays a critical role in minimizing predation risk. Plovers nest in sites with little vegetation cover to maximize the incubating adult visibility, but many studies suggest a trade-off between nest-crypsis and predator detection strategies. However, this trade-off has not been explored in detail because methods used so far do not allow estimating the visibility with regards to critical factors such as slope or plant permeability to vision. Here, we tested the hypothesis that Kentish plovers select exposed sites according to a predator detection strategy, and the hypothesis that more concealed nests survive longer according to a crypsis strategy. To this end, we obtained an accurate estimation of the incubating adult's field of vision through a custom built inverted periscope. Our results showed that plovers selected nest sites with higher visibility than control points randomly selected with regards to humans and dogs, although nests located in sites with higher vegetation cover survived longer. In addition, the flushing distance (i.e., the distance at which incubating adults leave the nest when they detect a potential predator decreased with vegetation cover. Consequently, the advantages of concealing the nest were limited by the ability to detect predators, thus indirectly supporting the existence of the trade-off between crypsis and predator detection. Finally, human disturbance also constrained nest choice, forcing plovers to move to inland sites that were less suitable because of higher vegetation cover, and modulated flushing behavior, since plovers that were habituated to humans left their nests closer to potential predators. This constraint on the width of suitable breeding habitat is particularly relevant for the conservation of Kentish Plover in sand beaches, especially under the current context of
Trade-off of Elastic Structure and Q in Interpretations of Seismic Attenuation

Science.gov (United States)

Deng, Wubing; Morozov, Igor B.

2017-10-01

The quality factor Q is an important phenomenological parameter measured from seismic or laboratory seismic data and representing wave-energy dissipation rate. However, depending on the types of measurements and models or assumptions about the elastic structure, several types of Qs exist, such as intrinsic and scattering Qs, coda Q, and apparent Qs observed from wavefield fluctuations. We consider three general types of elastic structures that are commonly encountered in seismology: (1) shapes and dimensions of rock specimens in laboratory studies, (2) geometric spreading or scattering in body-, surface- and coda-wave studies, and (3) reflectivity on fine layering in reflection seismic studies. For each of these types, the measured Q strongly trades off with the (inherently limited) knowledge about the respective elastic structure. For the third of the above types, the trade-off is examined quantitatively in this paper. For a layered sequence of reflectors (e.g., an oil or gas reservoir or a hydrothermal zone), reflection amplitudes and phases vary with frequency, which is analogous to a reflection from a contrast in attenuation. We demonstrate a quantitative equivalence between phase-shifted reflections from anelastic zones and reflections from elastic layering. Reflections from the top of an elastic layer followed by weaker reflections from its bottom can appear as resulting from a low Q within or above this layer. This apparent Q can be frequency-independent or -dependent, according to the pattern of thin layering. Due to the layering, the interpreted Q can be positive or negative, and it can depend on source-receiver offsets. Therefore, estimating Q values from frequency-dependent or phase-shifted reflection amplitudes always requires additional geologic or rock-physics constraints, such as sparseness and/or randomness of reflectors, the absence of attenuation in certain layers, or specific physical mechanisms of attenuation. Similar conclusions about the
Educational Systems and the Trade-Off between Labor Market Allocation and Equality of Educational Opportunity

Science.gov (United States)

Bol, Thijs; van de Werfhorst, Herman G.

2013-01-01

Educational systems with a high level of tracking and vocational orientation have been shown to improve the allocation of school-leavers in the labor market. However, tracked educational systems are also known to increase inequality of educational opportunity. This presumed trade-off between equality and labor market preparation is clearly rooted…
Trade-offs and synergies between universal electricity access and climate change mitigation in Sub-Saharan Africa

NARCIS (Netherlands)

Dagnachew, Anteneh G.; Lucas, Paul L.; Hof, Andries F.; van Vuuren, Detlef P.

2018-01-01

Access to electricity services is fundamental to development, as it enables improvements to the quality of human life. At the same time, increasing electricity access can have notable consequences for global climate change. This paper analyses trade-offs and synergies between achieving universal
Synergies and trade-offs in achieving global biodiversity targets.

Science.gov (United States)

Di Marco, Moreno; Butchart, Stuart H M; Visconti, Piero; Buchanan, Graeme M; Ficetola, Gentile F; Rondinini, Carlo

2016-02-01

After their failure to achieve a significant reduction in the global rate of biodiversity loss by 2010, world governments adopted 20 new ambitious Aichi biodiversity targets to be met by 2020. Efforts to achieve one particular target can contribute to achieving others, but different targets may sometimes require conflicting solutions. Consequently, lack of strategic thinking might result, once again, in a failure to achieve global commitments to biodiversity conservation. We illustrate this dilemma by focusing on Aichi Target 11. This target requires an expansion of terrestrial protected area coverage, which could also contribute to reducing the loss of natural habitats (Target 5), reducing human-induced species decline and extinction (Target 12), and maintaining global carbon stocks (Target 15). We considered the potential impact of expanding protected areas to mitigate global deforestation and the consequences for the distribution of suitable habitat for >10,000 species of forest vertebrates (amphibians, birds, and mammals). We first identified places where deforestation might have the highest impact on remaining forests and then identified places where deforestation might have the highest impact on forest vertebrates (considering aggregate suitable habitat for species). Expanding protected areas toward locations with the highest deforestation rates (Target 5) or the highest potential loss of aggregate species' suitable habitat (Target 12) resulted in partially different protected area network configurations (overlapping with each other by about 73%). Moreover, the latter approach contributed to safeguarding about 30% more global carbon stocks than the former. Further investigation of synergies and trade-offs between targets would shed light on these and other complex interactions, such as the interaction between reducing overexploitation of natural resources (Targets 6, 7), controlling invasive alien species (Target 9), and preventing extinctions of native
A Developmental Window into Trade-offs in Executive Function: The Case of Task Switching versus Response Inhibition in 6-year-olds

OpenAIRE

Blackwell, Katharine A.; Chatham, Christopher H.; Wiseheart, Melody; Munakata, Yuko

2014-01-01

Good executive function has been linked to many positive outcomes in academic performance, health, and social competence. However, some aspects of executive function may interfere with other cognitive processes. Childhood provides a unique test case for investigating such cognitive trade-offs, given the dramatic failures and developments observed during this period. For example, most children categorically switch or perseverate when asked to switch between rules on a card-sorting task. To tes...

A mechanical chest compressor closed-loop controller with an effective trade-off between blood flow improvement and ribs fracture reduction.

Science.gov (United States)

Zhang, Guang; Wu, Taihu; Song, Zhenxing; Wang, Haitao; Lu, Hengzhi; Wang, Yalin; Wang, Dan; Chen, Feng

2015-06-01

Chest compression (CC) is a significant emergency medical procedure for maintaining circulation during cardiac arrest. Although CC produces the necessary blood flow for patients with heart arrest, improperly deep CC will contribute significantly to the risk of chest injury. In this paper, an optimal CC closed-loop controller for a mechanical chest compressor (OCC-MCC) was developed to provide an effective trade-off between the benefit of improved blood perfusion and the risk of ribs fracture. The trade-off performance of the OCC-MCC during real automatic mechanical CCs was evaluated by comparing the OCC-MCC and the traditional mechanical CC method (TMCM) with a human circulation hardware model based on hardware simulations. A benefit factor (BF), risk factor (RF) and benefit versus risk index (BRI) were introduced in this paper for the comprehensive evaluation of risk and benefit. The OCC-MCC was developed using the LabVIEW control platform and the mechanical chest compressor (MCC) controller. PID control is also employed by MCC for effective compression depth regulation. In addition, the physiological parameters model for MCC was built based on a digital signal processor for hardware simulations. A comparison between the OCC-MCC and TMCM was then performed based on the simulation test platform which is composed of the MCC, LabVIEW control platform, physiological parameters model for MCC and the manikin. Compared with the TMCM, the OCC-MCC obtained a better trade-off and a higher BRI in seven out of a total of nine cases. With a higher mean value of cardiac output (1.35 L/min) and partial pressure of end-tidal CO2 (15.7 mmHg), the OCC-MCC obtained a larger blood flow and higher BF than TMCM (5.19 vs. 3.41) in six out of a total of nine cases. Although it is relatively difficult to maintain a stable CC depth when the chest is stiff, the OCC-MCC is still superior to the TMCM for performing safe and effective CC during CPR. The OCC-MCC is superior to the TMCM in
Local versus Global Environmental Performance of Dairying and Their Link to Economic Performance: A Case Study of Swiss Mountain Farms

Directory of Open Access Journals (Sweden)

Nina Repar

2016-12-01

Full Text Available Complying with the carrying capacity of local and global ecosystems is a prerequisite to ensure environmental sustainability. Based on the example of Swiss mountain dairy farms, the goal of our research was firstly to investigate the relationship between farm global and local environmental performance. Secondly, we aimed to analyse the relationship between farm environmental and economic performance. The analysis relied on a sample of 56 Swiss alpine dairy farms. For each farm, the cradle-to-farm-gate life cycle assessment was calculated, and the quantified environmental impacts were decomposed into their on- and off-farm parts. We measured global environmental performance as the digestible energy produced by the farm per unit of global environmental impact generated from cradle-to-farm-gate. We assessed local environmental performance by dividing farm-usable agricultural area by on-farm environmental impact generation. Farm economic performance was measured by work income per family work unit, return on equity and output/input ratio. Spearman’s correlation analysis revealed no significant relationship, trade-offs or synergies between global and local environmental performance indicators. Interestingly, trade-offs were observed far more frequently than synergies. Furthermore, we found synergies between global environmental and economic performance and mostly no significant relationship between local environmental and economic performance. The observed trade-offs between global and local environmental performance mean that, for several environmental issues, any improvement in global environmental performance will result in deterioration of local environmental performance and vice versa. This finding calls for systematic consideration of both dimensions when carrying out farm environmental performance assessments.
Costs and trade-offs of grazer-induced defenses in Scenedesmus under deficient resource

Science.gov (United States)

Zhu, Xuexia; Wang, Jun; Chen, Qinwen; Chen, Ge; Huang, Yuan; Yang, Zhou

2016-01-01

The green alga Scenedesmus obliquus can form inducible defensive morphs under grazing threat. Costs and trade-offs of inducible defense are expected to accompany the benefits of defensive morphs, but are hard to detect under nutrient-sufficient experimental conditions. To test the existence of costs associated with inducible defense, we cultured S. obliquus along resource availability gradients in the presence or absence of infochemical cues from Daphnia, and measured the strength of defensive colony formation and fitness characters. Under the lowest phosphorous concentration, the expression of inducible defensive colony resulted in decreased growth rate, which provides direct evidence for physiological costs. Along the gradient reduction of phosphorous concentration or light intensity, inducible defense in S. obliquus showed a decreasing trend. However, the photosynthetic efficiency of S. obliquus was barely affected by its defense responses, suggesting that the negative correlations between resource availability and colony formation of this alga may be due to resource-based trade-offs in the allocation of limited resources. Thus, our results indicated that expression of inducible defense of S. obliquus was impaired under insufficient phosphorus or light. Furthermore, under severe phosphate deficiency, obvious physiological costs of inducible defense could be detected even though defensive colony formation also decreased significantly. PMID:26932369
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.
A hybrid input–output multi-objective model to assess economic–energy–environment trade-offs in Brazil

International Nuclear Information System (INIS)

Carvalho, Ariovaldo Lopes de; Antunes, Carlos Henggeler; Freire, Fausto; Henriques, Carla Oliveira

2015-01-01

A multi-objective linear programming (MOLP) model based on a hybrid Input–Output (IO) framework is presented. This model aims at assessing the trade-offs between economic, energy, environmental (E3) and social objectives in the Brazilian economic system. This combination of multi-objective models with Input–Output Analysis (IOA) plays a supplementary role in understanding the interactions between the economic and energy systems, and the corresponding impacts on the environment, offering a consistent framework for assessing the effects of distinct policies on these systems. Firstly, the System of National Accounts (SNA) is reorganized to include the National Energy Balance, creating a hybrid IO framework that is extended to assess Greenhouse Gas (GHG) emissions and the employment level. The objective functions considered are the maximization of GDP (gross domestic product) and employment levels, as well as the minimization of energy consumption and GHG emissions. An interactive method enabling a progressive and selective search of non-dominated solutions with distinct characteristics and underlying trade-offs is utilized. Illustrative results indicate that the maximization of GDP and the employment levels lead to an increase of both energy consumption and GHG emissions, while the minimization of either GHG emissions or energy consumption cause negative impacts on GDP and employment. - Highlights: • A hybrid Input–Output multi-objective model is applied to the Brazilian economy. • Objective functions are GDP, employment level, energy consumption and GHG emissions. • Interactive search process identifies trade-offs between the competing objectives. • Positive correlations between GDP growth and employment. • Positive correlations between energy consumption and GHG emissions
Derivation of Optimal Operating Rules for Large-scale Reservoir Systems Considering Multiple Trade-off

Science.gov (United States)

Zhang, J.; Lei, X.; Liu, P.; Wang, H.; Li, Z.

2017-12-01

Flood control operation of multi-reservoir systems such as parallel reservoirs and hybrid reservoirs often suffer from complex interactions and trade-off among tributaries and the mainstream. The optimization of such systems is computationally intensive due to nonlinear storage curves, numerous constraints and complex hydraulic connections. This paper aims to derive the optimal flood control operating rules based on the trade-off among tributaries and the mainstream using a new algorithm known as weighted non-dominated sorting genetic algorithm II (WNSGA II). WNSGA II could locate the Pareto frontier in non-dominated region efficiently due to the directed searching by weighted crowding distance, and the results are compared with those of conventional operating rules (COR) and single objective genetic algorithm (GA). Xijiang river basin in China is selected as a case study, with eight reservoirs and five flood control sections within four tributaries and the mainstream. Furthermore, the effects of inflow uncertainty have been assessed. Results indicate that: (1) WNSGA II could locate the non-dominated solutions faster and provide better Pareto frontier than the traditional non-dominated sorting genetic algorithm II (NSGA II) due to the weighted crowding distance; (2) WNSGA II outperforms COR and GA on flood control in the whole basin; (3) The multi-objective operating rules from WNSGA II deal with the inflow uncertainties better than COR. Therefore, the WNSGA II can be used to derive stable operating rules for large-scale reservoir systems effectively and efficiently.
Framework for Architecture Trade Study Using MBSE and Performance Simulation

Science.gov (United States)

Ryan, Jessica; Sarkani, Shahram; Mazzuchim, Thomas

2012-01-01

Increasing complexity in modern systems as well as cost and schedule constraints require a new paradigm of system engineering to fulfill stakeholder needs. Challenges facing efficient trade studies include poor tool interoperability, lack of simulation coordination (design parameters) and requirements flowdown. A recent trend toward Model Based System Engineering (MBSE) includes flexible architecture definition, program documentation, requirements traceability and system engineering reuse. As a new domain MBSE still lacks governing standards and commonly accepted frameworks. This paper proposes a framework for efficient architecture definition using MBSE in conjunction with Domain Specific simulation to evaluate trade studies. A general framework is provided followed with a specific example including a method for designing a trade study, defining candidate architectures, planning simulations to fulfill requirements and finally a weighted decision analysis to optimize system objectives.
Sustainability of pasture-based livestock farming systems in the European Mediterranean context: Synergies and trade-offs

NARCIS (Netherlands)

Bernués, A.; Ruiz, R.; Olaizola, A.; Villalba, D.; Casasús, I.

2011-01-01

The sustainability of livestock farming systems (LFS) in relation to global concerns about climate change, population dynamics and the quality of the agro-ecosystem services that are provided to society and their trade-offs has become a fundamental issue for public and scientific debate. However,
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
Behavioural mediators of genetic life-history trade-offs: a test of the pace-of-life syndrome hypothesis in field crickets.

Science.gov (United States)

Santostefano, Francesca; Wilson, Alastair J; Niemelä, Petri T; Dingemanse, Niels J

2017-10-11

The pace-of-life syndrome (POLS) hypothesis predicts associations between life history and 'risky' behaviours. Individuals with 'fast' lifestyles should develop faster, reproduce earlier, exhibit more risk-prone behaviours, and die sooner than those with 'slow' lifestyles. While support for POLS has been equivocal to date, studies have relied on individual-level (phenotypic) patterns in which genetic trade-offs may be masked by environmental effects on phenotypes. We estimated genetic correlations between life history (development, lifespan, size) and risky behaviours (exploration, aggression) in a pedigreed population of Mediterranean field crickets ( Gryllus bimaculatus ). Path analyses showed that behaviours mediated some genetic relationships between life history traits, though not those involved in trade-offs. Thus, while specific predictions of POLS theory were not supported, genetic integration of behaviour and life history was present. This implies a major role for risky behaviours in life history evolution. © 2017 The Author(s).
An Information-Based Trade Off between Foreign Direct Investment and Foreign Portfolio Investment

OpenAIRE

Itay Goldstein; Assaf Razin

2005-01-01

The paper develops a model of foreign direct investments (FDI) and foreign portfolio investments (FPI).The model describes an information-based trade off between direct investments and portfolio investments. Direct investors are more informed about the fundamentals of their projects. This information enables them to manage their projects more efficiently. However, it also creates an asymmetric-information problem in case they need to sell their projects prematurely, and reduces the price they...
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.
Trade-off between synergy and efficacy in combinations of HIV-1 latency-reversing agents.

Science.gov (United States)

Gupta, Vipul; Dixit, Narendra M

2018-02-01

Eradicating HIV-1 infection is difficult because of the reservoir of latently infected cells that gets established soon after infection, remains hidden from antiretroviral drugs and host immune responses, and retains the capacity to reignite infection following the cessation of treatment. Drugs called latency-reversing agents (LRAs) are being developed to reactivate latently infected cells and render them susceptible to viral cytopathicity or immune killing. Whereas individual LRAs have failed to induce adequate reactivation, pairs of LRAs have been identified recently that act synergistically and hugely increase reactivation levels compared to individual LRAs. The maximum synergy achievable with LRA pairs is of clinical importance, as it would allow latency-reversal with minimal drug exposure. Here, we employed stochastic simulations of HIV-1 transcription and translation in latently infected cells to estimate this maximum synergy. We incorporated the predominant mechanisms of action of the two most promising classes of LRAs, namely, protein kinase C agonists and histone deacetylase inhibitors, and quantified the activity of individual LRAs in the two classes by mapping our simulations to corresponding in vitro experiments. Without any adjustable parameters, our simulations then quantitatively captured experimental observations of latency-reversal when the LRAs were used in pairs. Performing simulations representing a wide range of drug concentrations, we estimated the maximum synergy achievable with these LRA pairs. Importantly, we found with all the LRA pairs we considered that concentrations yielding the maximum synergy did not yield the maximum latency-reversal. Increasing concentrations to increase latency-reversal compromised synergy, unravelling a trade-off between synergy and efficacy in LRA combinations. The maximum synergy realizable with LRA pairs would thus be restricted by the desired level of latency-reversal, a constrained optimum we elucidated with
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...
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.
Nest Construction by a Ground-nesting Bird Represents a Potential Trade-off Between Egg Crypticity and Thermoregulation

Science.gov (United States)

Predation selects against conspicuous colors in bird eggs and nests, while thermoregulatory constraints select for nest building behavior that regulates incubation temperatures. We present results that reveal a trade-off between nest crypticity and thermoregulation of eggs base...
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.
Features of spatial and functional segregation and integration of the primate connectome revealed by trade-off between wiring cost and efficiency.

Directory of Open Access Journals (Sweden)

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
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.)

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...
Treatment preferences and trade-offs for ovulation induction in clomiphene citrate-resistant patients with polycystic ovary syndrome

NARCIS (Netherlands)

Bayram, Neriman; van Wely, Madelon; van der Veen, Fulco; Bossuyt, Patrick M. M.; Nieuwkerk, Pythia

2005-01-01

Objective: To investigate patient preferences and trade-offs for laparoscopic electrocautery of the ovaries relative to ovulation induction with recombinant FSH (rFSH) in patients with clomiphene citrate (CC)-resistant polycystic ovary syndrome (PCOS). Design: Assessment of preferences and
Design trade-off and proof of concept for LOUPE, the Lunar Observatory for Unresolved Polarimetry of Earth.

Science.gov (United States)

Hoeijmakers, H J; Arts, M L J; Snik, F; Keller, C U; Kuiper, J M

2016-09-19

We provide a proof of the technical feasibility of LOUPE, the first integral-field snapshot spectropolarimeter, designed to monitor the reflected flux and polarization spectrum of Earth. These are to be used as benchmark data for the retrieval of biomarkers and atmospheric and surface characteristics from future direct observations of exoplanets. We perform a design trade-off for an implementation in which LOUPE performs snapshot integral-field spectropolarimetry at visible wavelengths. We used off-the-shelf optics to construct a polarization modulator, in which polarization information is encoded into the spectrum as a wavelength-dependent modulation, while spatial resolution is maintained using a micro-lens array. The performance of this design concept is validated in a laboratory setup. Our proof-of-concept is capable of measuring a grid of 50 × 50 polarization spectra between 610 and 780 nm of a mock target planet - proving the merit of this design. The measurements are affected by systematic noise on the percent level, and we discuss how to mitigate this in future iterations. We conclude that LOUPE can be small and robust while meeting the science goals of this particular space application, and note the many potential applications that may benefit from our concept for doing snapshot integral-field spectropolarimetry.
Cost-benefit trade-offs of bird activity in apple orchards.

Science.gov (United States)

Peisley, Rebecca K; Saunders, Manu E; Luck, Gary W

2016-01-01

Birds active in apple orchards in south-eastern Australia can contribute positively (e.g., control crop pests) or negatively (e.g., crop damage) to crop yields. Our study is the first to identify net outcomes of these activities, using six apple orchards, varying in management intensity, in south-eastern Australia as a study system. We also conducted a predation experiment using real and artificial codling moth (Cydia pomonella) larvae (a major pest in apple crops). We found that: (1) excluding birds from branches of apple trees resulted in an average of 12.8% more apples damaged by insects; (2) bird damage to apples was low (1.9% of apples); and (3) when trading off the potential benefits (biological control) with costs (bird damage to apples), birds provided an overall net benefit to orchard growers. We found that predation of real codling moth larvae was higher than for plasticine larvae, suggesting that plasticine prey models are not useful for inferring actual predation levels. Our study shows how complex ecological interactions between birds and invertebrates affect crop yield in apples, and provides practical strategies for improving the sustainability of orchard systems.
Cost-benefit trade-offs of bird activity in apple orchards

Directory of Open Access Journals (Sweden)

Rebecca K. Peisley

2016-06-01

Full Text Available Birds active in apple orchards in south–eastern Australia can contribute positively (e.g., control crop pests or negatively (e.g., crop damage to crop yields. Our study is the first to identify net outcomes of these activities, using six apple orchards, varying in management intensity, in south–eastern Australia as a study system. We also conducted a predation experiment using real and artificial codling moth (Cydia pomonella larvae (a major pest in apple crops. We found that: (1 excluding birds from branches of apple trees resulted in an average of 12.8% more apples damaged by insects; (2 bird damage to apples was low (1.9% of apples; and (3 when trading off the potential benefits (biological control with costs (bird damage to apples, birds provided an overall net benefit to orchard growers. We found that predation of real codling moth larvae was higher than for plasticine larvae, suggesting that plasticine prey models are not useful for inferring actual predation levels. Our study shows how complex ecological interactions between birds and invertebrates affect crop yield in apples, and provides practical strategies for improving the sustainability of orchard systems.
Trade-offs and Opportunities in the Nexus of Energy and Water-for-Food

Science.gov (United States)

Rosegrant, M. W.

2015-12-01

The world economy is under pressure for greater, more efficient and more sustainable use of natural resources to meet complementary and competing objectives in the energy, water, and food sectors. Increasing national, regional, and seasonal water scarcities in much of the world pose severe challenges for national governments, the international development community, and ultimately, for individual water users. This presentation assesses the nexus between energy and water, with an emphasis on the interactions and trade-offs between energy and water for food production. It examines the impact of biofuel production on water quantity and quality, and the potential for hydropower potential to meet energy challenges while expanding irrigation water supplies and food production potential, thereby enhancing global food security. Biofuel production affects both water quantity and quality. Expanding production of biofuels—through either crop-based production systems or direct biomass production—can significantly increase demand for water as more acreage is planted or the crop mix begins to favor thirstier crops; water demand for bio-refineries creates additional competition with agricultural water use. Water quality can also be adversely affected by increased acreage for fertilizer-intensive crops, such as maize or sugarcane, which can result in increased nitrate run-off and soil erosion. Hydropower has become a relatively forgotten part of the energy-water security picture that deserves renewed attention. Unlike biofuels, hydropower does not normally compete with agricultural water. Instead, development of hydropower could complement food production by developing dam structures and power that also provide irrigation water and support its distribution for growing food crops. But balanced hydropower policies require consideration of potential trade-offs with environmental and social impacts.
A Classroom Exercise to Examine the Trade-off between Mission Capacity and Life Cycle Cost

Science.gov (United States)

Kang, Keebom; Doerr, Kenneth H.

2015-01-01

This article presents a classroom exercise, centered on a simulation that has been used for 4 years in an MBA program to help students develop an understanding of the trade-offs involved in managing capital assets in the public sector. Though often ignored in business schools, "mission" is a key criterion that must be considered when…
Theory of circuit block switch-off

Directory of Open Access Journals (Sweden)

S. Henzler

2004-01-01

Full Text Available Switching-off unused circuit blocks is a promising approach to supress static leakage currents in ultra deep sub-micron CMOS digital systems. Basic performance parameters of Circuit Block Switch-Off (CBSO schemes are defined and their dependence on basic circuit parameters is estimated. Therefore the design trade-off between strong leakage suppression in idle mode and adequate dynamic performance in active mode can be supported by simple analytic investigations. Additionally, a guideline for the estimation of the minimum time for which a block deactivation is useful is derived.
Essays on equity-efficiency trade offs in energy and climate policies

Science.gov (United States)

Sesmero, Juan P.

Economic efficiency and societal equity are two important goals of public policy. Energy and climate policies have the potential to affect both. Efficiency is increased by substituting low-carbon energy for fossil energy (mitigating an externality) while equity is served if such substitution enhances consumption opportunities of unfavored groups (low income households or future generations). However policies that are effective in reducing pollution may not be so effective in redistributing consumption and vice-versa. This dissertation explores potential trade-offs between equity and efficiency arising in energy and climate policies. Chapter 1 yields two important results. First, while effective in reducing pollution, energy efficiency policies may fall short in protecting future generations from resource depletion. Second, deployment of technologies that increase the ease with which capital can substitute for energy may enhance the ability of societies to sustain consumption and achieve intertemporal equity. Results in Chapter 1 imply that technologies more intensive in capital and materials and less intensive in carbon such as corn ethanol may be effective in enhancing intertemporal equity. However the effectiveness of corn ethanol (relative to other technologies) in reducing emissions will depend upon the environmental performance of the industry. Chapter 2 measures environmental efficiency of ethanol plants, identifies ways to enhance performance, and calculates the cost of such improvements based on a survey of ethanol plants in the US. Results show that plants may be able to increase profits and reduce emissions simultaneously rendering the ethanol industry more effective in tackling efficiency. Finally while cap and trade proposals are designed to correcting a market failure by reducing pollution, allocation of emission allowances may affect income distribution and, hence, intra-temporal equity. Chapter 3 proves that under plausible conditions on preferences
Experimentally induced spermatophore production and immune responses reveal a trade-off in crickets

OpenAIRE

Angela M. Kerr; Susan N. Gershman; Scott K. Sakaluk

2010-01-01

The energetic demands of the immune system and reproduction are often high and can lead to trade-offs between these 2 life-history traits. In decorated crickets, Gryllodes sigillatus, much of a male's reproductive effort is devoted to calling, and to the synthesis of a spermatophylax, a large, gelatinous, non--sperm-containing mass forming part of the spermatophore and consumed by the female after mating. We employed a reciprocal design in which we experimentally induced an immune response in...
Ecological Equivalence Assessment Methods: What Trade-Offs between Operationality, Scientific Basis and Comprehensiveness?

Science.gov (United States)

Bezombes, Lucie; Gaucherand, Stéphanie; Kerbiriou, Christian; Reinert, Marie-Eve; Spiegelberger, Thomas

2017-08-01

In many countries, biodiversity compensation is required to counterbalance negative impacts of development projects on biodiversity by carrying out ecological measures, called offset when the goal is to reach "no net loss" of biodiversity. One main issue is to ensure that offset gains are equivalent to impact-related losses. Ecological equivalence is assessed with ecological equivalence assessment methods taking into account a range of key considerations that we summarized as ecological, spatial, temporal, and uncertainty. When equivalence assessment methods take into account all considerations, we call them "comprehensive". Equivalence assessment methods should also aim to be science-based and operational, which is challenging. Many equivalence assessment methods have been developed worldwide but none is fully satisfying. In the present study, we examine 13 equivalence assessment methods in order to identify (i) their general structure and (ii) the synergies and trade-offs between equivalence assessment methods characteristics related to operationality, scientific-basis and comprehensiveness (called "challenges" in his paper). We evaluate each equivalence assessment methods on the basis of 12 criteria describing the level of achievement of each challenge. We observe that all equivalence assessment methods share a general structure, with possible improvements in the choice of target biodiversity, the indicators used, the integration of landscape context and the multipliers reflecting time lags and uncertainties. We show that no equivalence assessment methods combines all challenges perfectly. There are trade-offs between and within the challenges: operationality tends to be favored while scientific basis are integrated heterogeneously in equivalence assessment methods development. One way of improving the challenges combination would be the use of offset dedicated data-bases providing scientific feedbacks on previous offset measures.
A Longitudinal Study of the Effects of Innovativeness on Academic Spin-offs Performance

DEFF Research Database (Denmark)

Giones, Ferran; Billström, Anders; Rasmussen, Einar

, between 2000 and 2012, of 125 academic spin-offs of Norway provides valuable insights on how the origin of the technology impact differences in market performance. The results show how specific elements related to the ASOs’ product innovativeness contribute to its market performance. The findings provide......Academic Spin-Offs are given the mission to bring to society science and technology innovations. Nevertheless, the relative weak financial performance of these firms has recently been a focus of discussion. Prior research has explored factors that might explain the performance diversity, including...... aspects related to the academic entrepreneur (e.g. human capital), organizational (e.g. team characteristics, board composition, network of partners) and institutional factors (e.g. university context, support mechanisms). An under studied potential source of heterogeneity is the diversity of technologies...
On the network convergence process in RPL over IEEE 802.15.4 multihop networks: improvement and trade-offs.

Science.gov (United States)

Kermajani, Hamidreza; Gomez, Carles

2014-07-07

The IPv6 Routing Protocol for Low-power and Lossy Networks (RPL) has been recently developed by the Internet Engineering Task Force (IETF). Given its crucial role in enabling the Internet of Things, a significant amount of research effort has already been devoted to RPL. However, the RPL network convergence process has not yet been investigated in detail. In this paper we study the influence of the main RPL parameters and mechanisms on the network convergence process of this protocol in IEEE 802.15.4 multihop networks. We also propose and evaluate a mechanism that leverages an option available in RPL for accelerating the network convergence process. We carry out extensive simulations for a wide range of conditions, considering different network scenarios in terms of size and density. Results show that network convergence performance depends dramatically on the use and adequate configuration of key RPL parameters and mechanisms. The findings and contributions of this work provide a RPL configuration guideline for network convergence performance tuning, as well as a characterization of the related performance trade-offs.
On the Network Convergence Process in RPL over IEEE 802.15.4 Multihop Networks: Improvement and Trade-Offs

Directory of Open Access Journals (Sweden)

Hamidreza Kermajani

2014-07-01

Full Text Available The IPv6 Routing Protocol for Low-power and Lossy Networks (RPL has been recently developed by the Internet Engineering Task Force (IETF. Given its crucial role in enabling the Internet of Things, a significant amount of research effort has already been devoted to RPL. However, the RPL network convergence process has not yet been investigated in detail. In this paper we study the influence of the main RPL parameters and mechanisms on the network convergence process of this protocol in IEEE 802.15.4 multihop networks. We also propose and evaluate a mechanism that leverages an option available in RPL for accelerating the network convergence process. We carry out extensive simulations for a wide range of conditions, considering different network scenarios in terms of size and density. Results show that network convergence performance depends dramatically on the use and adequate configuration of key RPL parameters and mechanisms. The findings and contributions of this work provide a RPL configuration guideline for network convergence performance tuning, as well as a characterization of the related performance trade-offs.
Signal-to-noise ratio, contrast-to-noise ratio and their trade-offs with resolution in axial-shear strain elastography

International Nuclear Information System (INIS)

Thitaikumar, Arun; Krouskop, Thomas A; Ophir, Jonathan

2007-01-01

In axial-shear strain elastography, the local axial-shear strain resulting from the application of quasi-static axial compression to an inhomogeneous material is imaged. In this paper, we investigated the image quality of the axial-shear strain estimates in terms of the signal-to-noise ratio (SNR asse ) and contrast-to-noise ratio (CNR asse ) using simulations and experiments. Specifically, we investigated the influence of the system parameters (beamwidth, transducer element pitch and bandwidth), signal processing parameters (correlation window length and axial window shift) and mechanical parameters (Young's modulus contrast, applied axial strain) on the SNR asse and CNR asse . The results of the study show that the CNR asse (SNR asse ) is maximum for axial-shear strain values in the range of 0.005-0.03. For the inclusion/background modulus contrast range considered in this study ( asse (SNR asse ) is maximum for applied axial compressive strain values in the range of 0.005%-0.03%. This suggests that the RF data acquired during axial elastography can be used to obtain axial-shear strain elastograms, since this range is typically used in axial elastography as well. The CNR asse (SNR asse ) remains almost constant with an increase in the beamwidth while it increases as the pitch increases. As expected, the axial shift had only a weak influence on the CNR asse (SNR asse ) of the axial-shear strain estimates. We observed that the differential estimates of the axial-shear strain involve a trade-off between the CNR asse (SNR asse ) and the spatial resolution only with respect to pitch and not with respect to signal processing parameters. Simulation studies were performed to confirm such an observation. The results demonstrate a trade-off between CNR asse and the resolution with respect to pitch
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.
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
The effect of klapskate hinge position on push-off performance: a simulation study

NARCIS (Netherlands)

Houdijk, J.H.P.; Bobbert, M.F.; de Koning, J.J.; de Groot, G.

2003-01-01

Purpose: The introduction of the klapskate in speed skating confronts skaters with the question of how to adjust the position of the hinge in order to maximize performance. The purpose of this study was to reveal the constraint that klapskate hinge position imposes on push-off performance in speed
The trade-off between safety and efficiency in hydraulic architecture in 31 woody species in a karst area.

Science.gov (United States)

Fan, Da-Yong; Jie, Sheng-Lin; Liu, Chang-Cheng; Zhang, Xiang-Ying; Xu, Xin-Wu; Zhang, Shou-Ren; Xie, Zong-Qiang

2011-08-01

Karst topography is a special landscape shaped by the dissolution of one or more layers of soluble bedrock, usually carbonate rock such as limestone or dolomite. Due to subterranean drainage, overland flow, extraction of water by plants and evapotranspiration, there may be very limited surface water. The hydraulic architecture that plants use to adapt to karst topography is very interesting, but few systematic reports exist. The karst area in southwestern China is unique when compared with other karst areas at similar latitudes, because of its abundant precipitation, with rainfall concentrated in the growing season. In theory, resistance to water-stress-induced cavitation via air seeding should be accompanied by decreased pore hydraulic conductivity and stem hydraulic conductivity. However, evidence for such trade-offs across species is ambiguous. We measured the hydraulic structure and foliar stable carbon isotope ratios of 31 karst woody plants at three locations in Guizhou Province, China, to evaluate the functional coordination between resistance to cavitation and specific conductivity. We also applied phylogenetically independent contrast (PIC) analysis in situations where the inter-species correlations of functional traits may be biased on the potential similarity of closely related species. The average xylem tension measurement, at which 50% of hydraulic conductivity of the plants was lost (Ψ(50)), was only -1.27 MPa. Stem Ψ(50) was positively associated with specific conductance (K(s)) (P sapwood area:leaf area ratio) was negatively correlated with K(s) in both the traditional cross-species correlation and the corresponding PIC correlations (P < 0.01). The characteristics of hydraulic architecture measured in this study showed that karst plants in China are not highly cavitation-resistant species. This study also supports the idea that there may not be an evolutionary trade-off between resistance to cavitation and specific conductivity in woody
Reference-dependent electric vehicle production strategy considering subsidies and consumer trade-offs

International Nuclear Information System (INIS)

Zhang, Xiang

2014-01-01

In this paper, we extend previous reference-dependence newsvendor research by incorporating both consumer trade-offs and government subsidies to evaluate the relevant influences on the optimal electric vehicle (EV) production decisions. We present the properties of the model, derive the closed-form solutions for the model given the relevant constraints, and use numerical experiments to illustrate the results. We find that subsidies, loss aversion, the performance of both EVs and internal combustion engine-powered vehicles (ICEVs), and the coefficient of variation of demand are significant factors influencing the optimal production quantity and the expected utilities of EV production. The high selling price and other high costs of ICEVs help offset the influence of loss aversion, whereas the high costs of EV enhance loss aversion. Our study enriches the literature on subsidies for EVs by establishing a behavioral model to incorporate the decision bias in terms of loss aversion at the firm level. These findings provide guiding principles for both policymakers and EV managers for making better strategies to promote EVs in the early immature market. - Highlights: • The performance of both electric vehicles (EVs) and internal combustion engine-power vehicles (ICEVs) influences the EV production decisions. • A loss averse EV manager produces less and obtains less the expected utility than a risk neutral one. • Subsidies help decrease the EV breakeven quantity, increase the optimal quantity, offset the influence of loss aversion. • Subsidies should be adjusted according to the performance of both EVs and the ICEVs, demand heterogeneity, and local conditions. • The high ICEVs costs help offset the influence of loss aversion, whereas the high EV costs enhance loss aversion

Evolution of increased competitiveness in cows trades off with reduced milk yield, fertility and more masculine morphology.

Science.gov (United States)

Sartori, Cristina; Mazza, Serena; Guzzo, Nadia; Mantovani, Roberto

2015-08-01

In some species females compete for food, foraging territories, mating, and nesting sites. Competing females can exhibit morphological, physiological, and behavioral adaptations typical of males, which are commonly considered as secondary sexual traits. Competition and the development of traits increasing competitiveness require much energy and may exert adverse effects on fecundity and survival. From an evolutionary perspective, positive selection for increased competitiveness would then result in evolution of reduced values for traits related to fitness such as fecundity and survival. There is recent evidence for such evolutionary trade-offs involving male competition, but no study has considered competing females so far. Using data from competitions for dominance in cows (Bos taurus), we found negative genetic correlations between traits providing success in competition, that is, fighting ability and fitness traits related to milk production and with fertility (the inverse of parity-conception interval). Fighting ability also showed low but positive genetic correlations with "masculine" morphological traits, and negative correlations with "feminine" traits. A genetic change in traits over time has occurred due to selection on competitiveness, corresponding to an evolutionary process of "masculinization" counteracting the official selection for milk yield. Similar evolutionary trade-off between success in competition and fitness components may be present in various species experiencing female competition. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.
Micro water harvesting for climate change mitigation: Trade-offs between health and poverty reduction in Northern Ethiopia

NARCIS (Netherlands)

Fitsum, H.; Mekonen, Y.; Linderhof, V.G.M.; Kruseman, G.; Mulugeta, A.; Girmay, G.; Zenebe, A.

2006-01-01

Water harvesting is an important tool for mitigating the adverse effects of climate change. This report investigates the trade-offs between health and poverty reduction by considering the impacts of water harvesting on health in Tigray region, northern Ethiopia. In particular, we assess the
17 CFR 240.19c-3 - Governing off-board trading by members of national securities exchanges.

Science.gov (United States)

2010-04-01

... members of national securities exchanges. 240.19c-3 Section 240.19c-3 Commodity and Securities Exchanges... Members § 240.19c-3 Governing off-board trading by members of national securities exchanges. The rules of each national securities exchange shall provide as follows: (a) No rule, stated policy or practice of...
Fruit flies may face a nutrient-dependent life-history trade-off between secondary sexual trait quality, survival and developmental rate.

Science.gov (United States)

Gray, Lindsey J; Simpson, Stephen J; Polak, Michal

2018-01-01

Optimal life-history strategies are those that best allocate finite environmental resources to competing traits. We used the geometric framework for nutrition to evaluate life-history strategies followed by Drosophila melanogaster by measuring the condition-dependent performance of life-history traits, including the morphology of male secondary sexual characters, sex combs. We found that depending on their rearing environment flies faced different forms of trait trade-offs and accordingly followed different life-history strategies. High-energy, high-carbohydrate, low-protein diets supported development of the largest and most symmetrical sex combs, however, consistent with handicap models of sexual selection these foods were associated with reduced fly survival and developmental rate. Expressing the highest quality sex combs may have required secondary sexual trait quality to be traded-off with developmental rate, and our results indicated that flies unable to slow development died. As larval nutritional environments are predominantly determined by female oviposition substrate choice, we tested where mated female flies laid the most eggs. Mothers chose high-energy, high-protein foods associated with rapid larval development. Mothers avoided high-carbohydrate foods associated with maximal sex comb expression, showing they may avoid producing fewer 'sexy' sons in favour of producing offspring that develop rapidly. Copyright © 2017 Elsevier Ltd. All rights reserved.
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...
Optimal Time-Space Trade-Offs for Non-Comparison-Based Sorting

DEFF Research Database (Denmark)

Pagh, Rasmus; Pagter, Jacob Illeborg

2002-01-01

We study the problem of sorting n integers of w bits on a unit-cost RAM with word size w, and in particular consider the time-space trade-off (product of time and space in bits) for this problem. For comparison-based algorithms, the time-space complexity is known to be Θ(n2). A result of Beame...... shows that the lower bound also holds for non-comparison-based algorithms, but no algorithm has met this for time below the comparison-based Ω(nlgn) lower bound.We show that if sorting within some time bound &Ttilde; is possible, then time T = O(&Ttilde; + nlg* n) can be achieved with high probability...... using space S = O(n2/T + w), which is optimal. Given a deterministic priority queue using amortized time t(n) per operation and space nO(1), we provide a deterministic algorithm sorting in time T = O(n(t(n) + lg* n)) with S = O(n2/T + w). Both results require that w ≤ n1-Ω(1). Using existing priority...
Engineering Trade-off Considerations Regarding Design-for-Security, Design-for-Verification, and Design-for-Test

Science.gov (United States)

Berg, Melanie; Label, Kenneth

2018-01-01

The United States government has identified that application specific integrated circuit (ASIC) and field programmable gate array (FPGA) hardware are at risk from a variety of adversary attacks. This finding affects system security and trust. Consequently, processes are being developed for system mitigation and countermeasure application. The scope of this tutorial pertains to potential vulnerabilities and countermeasures within the ASIC/FPGA design cycle. The presentation demonstrates how design practices can affect the risk for the adversary to: change circuitry, steal intellectual property, and listen to data operations. An important portion of the design cycle is assuring the design is working as specified or as expected. This is accomplished by exhaustive testing of the target design. Alternatively, it has been shown that well established schemes for test coverage enhancement (design-for-verification (DFV) and design-for-test (DFT)) can create conduits for adversary accessibility. As a result, it is essential to perform a trade between robust test coverage versus reliable design implementation. The goal of this tutorial is to explain the evolution of design practices; review adversary accessibility points due to DFV and DFT circuitry insertion (back door circuitry); and to describe common engineering trade-off considerations for test versus adversary threats.
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...
Ecosystem accounts define explicit and spatial trade-offs for managing natural resources.

Science.gov (United States)

Keith, Heather; Vardon, Michael; Stein, John A; Stein, Janet L; Lindenmayer, David

2017-11-01

Decisions about natural resource management are frequently complex and vexed, often leading to public policy compromises. Discord between environmental and economic metrics creates problems in assessing trade-offs between different current or potential resource uses. Ecosystem accounts, which quantify ecosystems and their benefits for human well-being consistent with national economic accounts, provide exciting opportunities to contribute significantly to the policy process. We advanced the application of ecosystem accounts in a regional case study by explicitly and spatially linking impacts of human and natural activities on ecosystem assets and services to their associated industries. This demonstrated contributions of ecosystems beyond the traditional national accounts. Our results revealed that native forests would provide greater benefits from their ecosystem services of carbon sequestration, water yield, habitat provisioning and recreational amenity if harvesting for timber production ceased, thus allowing forests to continue growing to older ages.
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.
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.
Policy design and performance of emissions trading markets: an adaptive agent-based analysis.

Science.gov (United States)

Bing, Zhang; Qinqin, Yu; Jun, Bi

2010-08-01

Emissions trading is considered to be a cost-effective environmental economic instrument for pollution control. However, the pilot emissions trading programs in China have failed to bring remarkable success in the campaign for pollution control. The policy design of an emissions trading program is found to have a decisive impact on its performance. In this study, an artificial market for sulfur dioxide (SO2) emissions trading applying the agent-based model was constructed. The performance of the Jiangsu SO2 emissions trading market under different policy design scenario was also examined. Results show that the market efficiency of emissions trading is significantly affected by policy design and existing policies. China's coal-electricity price system is the principal factor influencing the performance of the SO2 emissions trading market. Transaction costs would also reduce market efficiency. In addition, current-level emissions discharge fee/tax and banking mechanisms do not distinctly affect policy performance. Thus, applying emissions trading in emission control in China should consider policy design and interaction with other existing policies.
Insight into trade-off between wood decay and parasitism from the genome of a fungal forest pathogen

Energy Technology Data Exchange (ETDEWEB)

Olson, Ake; Aerts, Andrea; Asiegbu, Fred; Belbahri, Lassaad; Bouzid, Ourdia; Broberg, Anders; Canback, Bjorn; Coutinho, Pedro M.; Cullen, Dan; Dalman, Kerstin; Deflorio, Giuliana; van Diepen, Linda T. A.; Dunand, Christophe; Duplessis, Sebastien; Durling, Mikael; Gonthier, Paolo; Grimwood, Jane; Fossdal, Carl Gunnar; Hansson, David; Henrissat, Bernard; Hietala, Ari; Himmelstrand, Kajsa; Hoffmeister, Dirk; Hogberg, Nils; James, Timothy Y.; Karlsson, Magnus; Kohler, Annegret; Lucas, Susan; Lunden, Karl; Morin, Emmanuelle; Murat, Claude; Park, Jongsun; Raffaello, Tommaso; Rouze, Pierre; Salamov, Asaf; Schmutz, Jeremy; Solheim, Halvor; Stahlberg, Jerry; Velez, Heriberto; de Vries, Ronald P.; Wiebenga, Ad; Woodward, Steve; Yakovlev, Igor; Garbelotto, Matteo; Martin, Francis; Grigoriev, Igor V.; Stenlid, Jan

2012-01-01

Parasitism and saprotrophic wood decay are two fungal strategies fundamental for succession and nutrient cycling in forest ecosystems. An opportunity to assess the trade-off between these strategies is provided by the forest pathogen and wood decayer Heterobasidion annosum sensu lato. We report the annotated genome sequence and transcript profiling, as well as the quantitative trait loci mapping, of one member of the species complex: H. irregulare. Quantitative trait loci critical for pathogenicity, and rich in transposable elements, orphan and secreted genes, were identified. A wide range of cellulose-degrading enzymes are expressed during wood decay. By contrast, pathogenic interaction between H. irregulare and pine engages fewer carbohydrate-active enzymes, but involves an increase in pectinolytic enzymes, transcription modules for oxidative stress and secondary metabolite production. Our results show a trade-off in terms of constrained carbohydrate decomposition and membrane transport capacity during interaction with living hosts. Our findings establish that saprotrophic wood decay and necrotrophic parasitism involve two distinct, yet overlapping, processes.
Economic trade-offs between genetic improvement and longevity in dairy cattle.

Science.gov (United States)

De Vries, A

2017-05-01

Genetic improvement in sires used for artificial insemination (AI) is increasing faster compared with a decade ago. The genetic merit of replacement heifers is also increasing faster and the genetic lag with older cows in the herd increases. This may trigger greater cow culling to capture this genetic improvement. On the other hand, lower culling rates are often viewed favorably because the costs and environmental effects of maintaining herd size are generally lower. Thus, there is an economic trade-off between genetic improvement and longevity in dairy cattle. The objective of this study was to investigate the principles, literature, and magnitude of these trade-offs. Data from the Council on Dairy Cattle Breeding show that the estimated breeding value of the trait productive life has increased for 50 yr but the actual time cows spend in the herd has not increased. The average annual herd cull rate remains at approximately 36% and cow longevity is approximately 59 mo. The annual increase in average estimated breeding value of the economic index lifetime net merit of Holstein sires is accelerating from $40/yr when the sire entered AI around 2002 to $171/yr for sires that entered AI around 2012. The expectation is therefore that heifers born in 2015 are approximately $50 more profitable per lactation than heifers born in 2014. Asset replacement theory shows that assets should be replaced sooner when the challenging asset is technically improved. Few studies have investigated the direct effects of genetic improvement on optimal cull rates. A 35-yr-old study found that the economically optimal cull rates were in the range of 25 to 27%, compared with the lowest possible involuntary cull rate of 20%. Only a small effect was observed of using the best surviving dams to generate the replacement heifer calves. Genetic improvement from sires had little effect on the optimal cull rate. Another study that optimized culling decisions for individual cows also showed that the
A trade-off between natural and acquired antibody production in a reptile: implications for long-term resistance to disease

Directory of Open Access Journals (Sweden)

Franziska C. Sandmeier

2012-08-01

Vertebrate immune systems are understood to be complex and dynamic, with trade-offs among different physiological components (e.g., innate and adaptive immunity within individuals and among taxonomic lineages. Desert tortoises (Gopherus agassizii immunised with ovalbumin (OVA showed a clear trade-off between levels of natural antibodies (NAbs; innate immune function and the production of acquired antibodies (adaptive immune function. Once initiated, acquired antibody responses included a long-term elevation in antibodies persisting for more than one year. The occurrence of either (a high levels of NAbs or (b long-term elevations of acquired antibodies in individual tortoises suggests that long-term humoral resistance to pathogens may be especially important in this species, as well as in other vertebrates with slow metabolic rates, concomitantly slow primary adaptive immune responses, and long life-spans.
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
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
Testing phenotypic trade-offs in the chemical defence strategy of Scots pine under growth-limiting field conditions.

Science.gov (United States)

Villari, Caterina; Faccoli, Massimo; Battisti, Andrea; Bonello, Pierluigi; Marini, Lorenzo

2014-09-01

Plants protect themselves from pathogens and herbivores through fine-tuned resource allocation, including trade-offs among resource investments to support constitutive and inducible defences. However, empirical research, especially concerning conifers growing under natural conditions, is still scarce. We investigated the complexity of constitutive and induced defences in a natural Scots pine (Pinus sylvestris L.) stand under growth-limiting conditions typical of alpine environments. Phenotypic trade-offs at three hierarchical levels were tested by investigating the behaviour of phenolic compounds and terpenoids of outer bark and phloem. We tested resource-derived phenotypic correlations between (i) constitutive and inducible defences vs tree ring growth, (ii) different constitutive defence metabolites and (iii) constitutive concentration and inducible variation of individual metabolites. Tree ring growth was positively correlated only with constitutive concentration of total terpenoids, and no overall phenotypic trade-offs between different constitutive defensive metabolites were found. At the lowest hierarchical level tested, i.e., at the level of relationship between constitutive and inducible variation of individual metabolites, we found that different compounds displayed different behaviours; we identified five different defensive metabolite response types, based on direction and strength of the response, regardless of tree age and growth rate. Therefore, under growth-limiting field conditions, Scots pine appears to utilize varied and complex outer bark and phloem defence chemistry, in which only part of the constitutive specialized metabolism is influenced by tree growth, and individual components do not appear to be expressed in a mutually exclusive manner in either constitutive or inducible metabolism. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
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.
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...

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.
Health or Happiness? A Note on Trading Off Health and Happiness in Rationing Decisions.

Science.gov (United States)

van de Wetering, E J; van Exel, N J A; Brouwer, W B F

2016-01-01

Economic evaluations typically value the effects of an intervention in terms of quality-adjusted life-years, which combine length and health-related quality of life. It has been suggested that economic evaluations should incorporate broader outcomes than health-related quality of life. Broader well-being, for instance measured as happiness, could be a better measure of the overall welfare effects in patients because of treatment. An underexplored question is whether and how people trade off information on health and broader outcomes from treatment in rationing decisions. This article presents the results of a first experiment aimed at exploring such trade-offs between health and happiness. We used a Web-based questionnaire in a representative sample of the public from the Netherlands (N = 1015). People made choices between two groups of patients differing in terms of their health and happiness levels before treatment and gains from treatment. The results showed that about half the respondents were willing to discriminate between patient groups on the basis of their health and happiness levels before and after treatment. In the trader group, health gains were considered somewhat more important than happiness gains. Our findings suggest that both health and happiness levels of patients may play a role in priority setting. Copyright © 2016 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.
The Air-Carbon-Water Synergies and Trade-Offs in China's Natural Gas Industry

Science.gov (United States)

Qin, Yue

China's coal-dominated energy structure is partly responsible for its domestic air pollution, local water stress, and the global climate change. Primarily to tackle the haze issue, China has been actively promoting a nationwide coal to natural gas end-use switch. My dissertation focuses on evaluating the air quality, carbon, and water impacts and their interactions in China's natural gas industry. Chapter 2 assesses the lifecycle climate performance of China's shale gas in comparison to coal based on stage-level energy consumption and methane leakage rates. I find the mean lifecycle carbon footprint of shale gas is about 30-50% lower than that of coal under both 20 year and 100 year global warming potentials (GWP20 and GWP100). However, primarily due to large uncertainties in methane leakage, the lifecycle carbon footprint of shale gas in China could be 15-60% higher than that of coal across sectors under GWP20. Chapter 3 evaluates the air quality, human health, and the climate impacts of China's coal-based synthetic natural gas (SNG) development. Based on earlier 2020 SNG production targets, I conduct an integrated assessment to identify production technologies and end-use applications that will bring as large air quality and health benefits as possible while keeping carbon penalties as small as possible. I find that, due to inefficient and uncontrolled coal combustion in households, allocating currently available SNG to the residential sector proves to be the best SNG allocation option. Chapter 4 compares the air quality, carbon, and water impacts of China's six major gas sources under three end-use substitution scenarios, which are focused on maximizing air pollutant emission reductions, CO 2 emission reductions, and water stress index (WSI)-weighted water consumption reductions, respectively. I find striking national air-carbon/water trade-offs due to SNG, which also significantly increases water demands and carbon emissions in regions already suffering from
Life history trade-offs and behavioral sensitivity to testosterone: an experimental test when female aggression and maternal care co-occur.

Directory of Open Access Journals (Sweden)

Kimberly A Rosvall

Full Text Available Research on male animals suggests that the hormone testosterone plays a central role in mediating the trade-off between mating effort and parental effort. However, the direct links between testosterone, intrasexual aggression and parental care are remarkably mixed across species. Previous attempts to reconcile these patterns suggest that selection favors behavioral insensitivity to testosterone when paternal care is essential to reproductive success and when breeding seasons are especially short. Females also secrete testosterone, though the degree to which similar testosterone-mediated trade-offs occur in females is much less clear. Here, I ask whether testosterone mediates trade-offs between aggression and incubation in females, and whether patterns of female sensitivity to testosterone relate to female life history, as is often the case in males. I experimentally elevated testosterone in free-living, incubating female tree swallows (Tachycineta bicolor, a songbird with a short breeding season during which female incubation and intrasexual aggression are both essential to female reproductive success. Testosterone-treated females showed significantly elevated aggression, reduced incubation temperatures, and reduced hatching success, relative to controls. Thus, prolonged testosterone elevation during incubation was detrimental to reproductive success, but females nonetheless showed behavioral sensitivity to testosterone. These findings suggest that the relative importance of both mating effort and parental effort may be central to understanding patterns of behavioral sensitivity in both sexes.
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.
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
Results of NASA/NOAA HES Trade Studies

Science.gov (United States)

Susskind, Joel

2011-01-01

This slide presentation reviews the trade studies that were done for the Hyperspectral Environmental Suite (HES). The goal of the trade studies was to minimize instrument cost and risk while producing scientifically useful products. Three vendors were selected to perform the trade study, and were to conduct 11 studies, with the first study a complete wish list of things that scientists would like from GEO orbit to the 11th study which was for a Reduced Accommodation Sounder (RAS) which would still result in useful scientific products, within constrains compatible with flight on GEOS-R. The RAS's from each vendor and one other HES sounders designs are reviewed.
Life Support Filtration System Trade Study for Deep Space Missions

Science.gov (United States)

Agui, Juan H.; Perry, Jay L.

2017-01-01

The National Aeronautics and Space Administrations (NASA) technical developments for highly reliable life support systems aim to maximize the viability of long duration deep space missions. Among the life support system functions, airborne particulate matter filtration is a significant driver of launch mass because of the large geometry required to provide adequate filtration performance and because of the number of replacement filters needed to a sustain a mission. A trade analysis incorporating various launch, operational and maintenance parameters was conducted to investigate the trade-offs between the various particulate matter filtration configurations. In addition to typical launch parameters such as mass, volume and power, the amount of crew time dedicated to system maintenance becomes an increasingly crucial factor for long duration missions. The trade analysis evaluated these parameters for conventional particulate matter filtration technologies and a new multi-stage particulate matter filtration system under development by NASAs Glenn Research Center. The multi-stage filtration system features modular components that allow for physical configuration flexibility. Specifically, the filtration system components can be configured in distributed, centralized, and hybrid physical layouts that can result in considerable mass savings compared to conventional particulate matter filtration technologies. The trade analysis results are presented and implications for future transit and surface missions are discussed.
Telomere Length and the Cancer-Atherosclerosis Trade-Off.

Directory of Open Access Journals (Sweden)

Rivka C Stone

2016-07-01

Full Text Available Modern humans, the longest-living terrestrial mammals, display short telomeres and repressed telomerase activity in somatic tissues compared with most short-living small mammals. The dual trait of short telomeres and repressed telomerase might render humans relatively resistant to cancer compared with short-living small mammals. However, the trade-off for cancer resistance is ostensibly increased age-related degenerative diseases, principally in the form of atherosclerosis. In this communication, we discuss (a the genetics of human telomere length, a highly heritable complex trait that is influenced by genetic ancestry, sex, and paternal age at conception, (b how cancer might have played a role in the evolution of telomere biology across mammals, (c evidence that in modern humans telomere length is a determinant (rather than only a biomarker of cancer and atherosclerosis, and (d the potential influence of relatively recent evolutionary forces in fashioning the variation in telomere length across and within populations, and their likely lasting impact on major diseases in humans. Finally, we propose venues for future research on human telomere genetics in the context of its potential role in shaping the modern human lifespan.
Three's a Crowd: Trade-Offs between Attracting Pollinators and Ant Bodyguards with Nectar Rewards in Turnera.

Science.gov (United States)

Dutton, Emily M; Luo, Elaine Y; Cembrowski, Adam R; Shore, Joel S; Frederickson, Megan E

2016-07-01

Many plants attract insect pollinators with floral nectar (FN) and ant "bodyguards" with extrafloral nectar (EFN). If nectar production is costly or physiologically linked across glands, investment in one mutualism may trade off with investment in the other. We confirmed that changes in FN and EFN availability alter pollination and ant defense mutualisms in a field population of Turnera ulmifolia. Plants with additional FN tended to produce more seeds, while plants with reduced EFN production experienced less florivory. We then mimicked the consumptive effects of mutualists by removing FN or EFN daily for 50 days in a full factorial design using three Turnera species (T. joelii, T. subulata, and T. ulmifolia) in a glasshouse experiment. For T. ulmifolia and T. subulata, but not T. joelii, removing either nectar reduced production of the other, showing for the first time that EFN and FN production can trade off. In T. subulata, increased investment in FN decreased seed set, suggesting that nectar production can have direct fitness costs. Through the linked expression of EFN and FN, floral visitors may negatively affect biotic defense, and extrafloral nectary visitors may negatively affect pollination.
Who is Willing to Sacrifice Sacred Values for Money and Social Status? Gender Differences in Reactions to Taboo Trade-offs

OpenAIRE

Kennedy, Jessica A.; Kray, Laura J.

2012-01-01

Women select into top business degree programs at a lower rate than men and are underrepresented in high-ranking positions in business organizations. We examined taboo trade-off aversion as one possible explanation for these patterns. In Study 1, we found that women implicitly associated business with immorality more than men did. In Study 2, when reading of decisions that compromised ethical values for social status and monetary gains, women reported feeling more moral outrage and perceived ...
Not-for-profit hospitals' provision of community benefit: is there a trade-off between charity care and other benefits provided to the community?

Science.gov (United States)

Singh, Simone Rauscher

2013-01-01

For decades, not-for-profit hospitals have been required to provide community benefit in exchange for tax exemption. To fulfill this requirement, hospitals engage in a variety of activities ranging from free and reduced cost care provided to individual patients to services aimed at improving the health of the community at large. Limited financial resources may restrict hospitals' ability to provide the full range of community benefits and force them to engage in trade-offs. We analyzed the composition of not-for-profit hospitals' community benefit expenditures and explored whether hospitals traded off between charity care and spending on other community benefit activities. Data for this study came from Maryland hospitals' state-level community benefit reports for 2006-2010. Bivariate Spearman's rho correlation analysis was used to examine the relationships among various components of hospitals' community benefit activities. We found no evidence of trade-offs between charity care and activities targeted at the health and well-being of the community at large. Consistently, hospitals that provided more charity care did not offset these expenditures by reducing their spending on other community benefit activities, including mission-driven health services, community health services, and health professions education. Hospitals' decisions about how to allocate community benefit dollars are made in the context of broader community health needs and resources. Concerns that hospitals serving a disproportionate number of charity patients might provide fewer benefits to the community at large appear to be unfounded.
Equity trade-offs in conservation decision making.

Science.gov (United States)

Law, Elizabeth A; Bennett, Nathan J; Ives, Christopher D; Friedman, Rachel; Davis, Katrina J; Archibald, Carla; Wilson, Kerrie A

2018-04-01

Conservation decisions increasingly involve multiple environmental and social objectives, which result in complex decision contexts with high potential for trade-offs. Improving social equity is one such objective that is often considered an enabler of successful outcomes and a virtuous ideal in itself. Despite its idealized importance in conservation policy, social equity is often highly simplified or ill-defined and is applied uncritically. What constitutes equitable outcomes and processes is highly normative and subject to ethical deliberation. Different ethical frameworks may lead to different conceptions of equity through alternative perspectives of what is good or right. This can lead to different and potentially conflicting equity objectives in practice. We promote a more transparent, nuanced, and pluralistic conceptualization of equity in conservation decision making that particularly recognizes where multidimensional equity objectives may conflict. To help identify and mitigate ethical conflicts and avoid cases of good intentions producing bad outcomes, we encourage a more analytical incorporation of equity into conservation decision making particularly during mechanistic integration of equity objectives. We recommend that in conservation planning motivations and objectives for equity be made explicit within the problem context, methods used to incorporate equity objectives be applied with respect to stated objectives, and, should objectives dictate, evaluation of equity outcomes and adaptation of strategies be employed during policy implementation. © 2017 Society for Conservation Biology.
Off-design performance analysis of a solar-powered organic Rankine cycle

International Nuclear Information System (INIS)

Wang, Jiangfeng; Yan, Zhequan; Zhao, Pan; Dai, Yiping

2014-01-01

Highlights: • Solar-powered organic Rankine cycle with CPC and thermal storage unit is studied. • Off-design performances encountering the changes of key parameters are examined. • Off-design performance is analyzed over a whole day and in different months. - Abstract: Performance evaluation of a thermodynamic system under off-design conditions is very important for reliable and cost-effective operation. In this study, an off-design model of an organic Rankine cycle driven by solar energy is established with compound parabolic collector (CPC) to collect the solar radiation and thermal storage unit to achieve the continuous operation of the overall system. The system off-design behavior is examined under the change in environment temperature, as well as thermal oil mass flow rates of vapor generator and CPC. In addition, the off-design performance of the system is analyzed over a whole day and in different months. The results indicate that a decrease in environment temperature, or the increases in thermal oil mass flow rates of vapor generator and CPC could improve the off-design performance. The system obtains the maximum average exergy efficiency in December and the maximum net power output in June or in September. Both the net power output and the average exergy efficiency reach minimum values in August
85Kr management trade-offs: a perspective to total radiation dose commitment

International Nuclear Information System (INIS)

Mellinger, P.J.; Hoenes, G.R.; Brackenbush, L.W.; Greenborg, J.

1980-01-01

Radiological consequences arising from the trade-offs for 85 Kr waste management from possible nuclear fuel resource recovery activities have been investigated. The reference management technique is to release all the waste gas to the atmosphere where it is diluted and dispersed. A potential alternative is to collect, concentrate, package and submit the gas to long-term storage. This study compares the radiation dose commitment to the public and to the occupationally exposed work force from these alternatives. The results indicate that it makes little difference to the magnitude of the world population dose whether 85 Kr is captured and stored or chronically released to the environment. Further, comparisons of radiation exposures (for the purpose of estimating health effects) at very low dose rates to very large populations with exposures to a small number of occupationally exposed workers who each receive much higher dose rates may be misleading. Finally, cost studies (EPA 1976 and DOE 1979a) show that inordinate amounts of money will be required to lower this already extremely small 80-year cumulative world population dose of 0.05 mrem/person
Interspecific Interactions and the Scope for Parent-Offspring Conflict: High Mite Density Temporarily Changes the Trade-Off between Offspring Size and Number in the Burying Beetle, Nicrophorus vespilloides.

Science.gov (United States)

De Gasperin, Ornela; Kilner, Rebecca M

2016-01-01

Parents have a limited amount of resources to invest in reproduction and commonly trade-off how much they invest in offspring size (or quality) versus brood size. A negative relationship between offspring size and number has been shown in numerous taxa and it underpins evolutionary conflicts of interest between parents and their young. For example, previous work on vertebrates shows that selection favours mothers that produce more offspring, at the expense of individual offspring size, yet favours offspring that have relatively few siblings and therefore attain a greater size at independence. Here we analyse how this trade-off is temporarily affected by stochastic variation in the intensity of interspecific interactions. We examined the effect of the mite Poecilochirus carabi on the relationship between offspring size and number in the burying beetle, Nicrophorus vespilloides. We manipulated the initial number of mites in the reproductive event (by introducing either no mites, 4 mites, 10 mites, or 16 mites), and assessed the effect on the brood. We found a similar trade-off between offspring size and number in all treatments, except in the '16 mite' treatment where the correlation between offspring number and size flattened considerably. This effect arose because larvae in small broods failed to attain a high mass by dispersal. Our results show that variation in the intensity of interspecific interactions can temporarily change the strength of the trade-off between offspring size and number. In this study, high densities of mites prevented individual offspring from attaining their optimal weight, thus potentially temporarily biasing the outcome of parent-offspring conflict in favour of parents.
Economics and ethics in mental health care: traditions and trade-offs.

Science.gov (United States)

Chisholm, Daniel; Stewart, Alan

1998-07-01

BACKGROUND: Both economic and ethical perspectives are exerting increasing influence at all levels of mental health policy and practice; yet there is little consensus on how these two different perspectives are to be reconciled or explicitly incorporated into decision-making. AIM: This review article is directed towards a fuller understanding of the complex trade-offs and compromises that are or may be made by clinicians, managers and policy-makers alike in the context of mental health care planning and delivery. METHOD: We briefly outline a number of key principles of health care economics and ethics, and then focus on the particular incentives and trade-offs that are raised by these principles at three levels of the mental health system: government and society; purchasers and providers; and users and carers. RESULTS: At the level of government and society, we find (economically influenced) attempts to reform mental health care offset by concerns revolving around access to care: whether society is prepared to forgo economic benefits in exchange for improved equity depends to a considerable extent on the prevailing ethical paradigm. The implementation of these reforms at the level of purchasers and providers has helped to focus attention on evaluation and prioritization, but has also introduced "perverse incentives" such as cost-shifting and cream-skimming, which can impede access to or continuity of appropriate care for mentally ill people. Finally, we detect opportunities for moral hazard and other forms of strategic behaviour that are thrown up by the nature of the carer:user relationship in mental health care. CONCLUSION: We conclude by highlighting the need to move towards a more open, accountable and evidence-based mental health care system. Acknowledgement of and progress towards these three requirements will not deliver ideal levels of efficiency or equity, but will foster a greater understanding of the relevance of ethical considerations to mental health
Time-space trade-offs for lempel-ziv compressed indexing

DEFF Research Database (Denmark)

Bille, Philip; Ettienne, Mikko Berggren; Gørtz, Inge Li

2017-01-01

Given a string S, the compressed indexing problem is to preprocess S into a compressed representation that supports fast substring queries. The goal is to use little space relative to the compressed size of S while supporting fast queries. We present a compressed index based on the Lempel-Ziv 1977...... compression scheme. Let n, and z denote the size of the input string, and the compressed LZ77 string, respectively. We obtain the following time-space trade-offs. Given a pattern string P of length m, we can solve the problem in (i) O (m + occ lg lg n) time using O(z lg(n/z) lg lg z) space, or (ii) (m (1...... best space bound, but has a leading term in the query time of O(m(1 + lgϵ z/lg(n/z))). However, for any polynomial compression ratio, i.e., z = O(n1-δ), for constant δ > 0, this becomes O(m). Our index also supports extraction of any substring of length ℓ in O(ℓ + lg(n/z)) time. Technically, our...
Quantifying Trade-Offs Among Ecosystem Services, Biodiversity, and Agricultural Returns in an Agriculturally Dominated Landscape Under Future Land‑Management Scenarios

Directory of Open Access Journals (Sweden)

Emma C. Underwood

2017-07-01

Full Text Available https://doi.org/10.15447/sfews.2017v15iss2art4Change in land use in agriculturally dominated areas is often assumed to provide positive benefits for land-owners and financial agricultural returns at the expense of biodiversity and other ecosystem services. For an agriculturally dominated area in the Central Valley of California we quantify the trade-offs among ecosystem services, biodiversity, and the financial returns from agricultural lands. We do this by evaluating three different landscape management scenarios projected to 2050 compared to the current baseline: habitat restoration, urbanization, and enhanced agriculture. The restoration scenario benefited carbon storage services and increased landscape suitability for birds, and also decreased ecosystem disservices (nitrous oxide emissions, nitrogen leaching, although there was a trade-off in slightly lower financial agricultural returns. Under the urbanization scenario, carbon storage, suitability for birds, and agricultural returns were negatively affected. A scenario which enhanced agriculture, tailored to the needs of a key species of conservation concern (Swainson’s Hawk, Buteo swainsoni, presented the most potential for trade-offs. This scenario benefitted carbon storage and increased landscape suitability for the Swainson's Hawk as well as 15 other focal bird species. However, this scenario increased ecosystem disservices. These spatially explicit results, generated at a scale relevant to land management decision-makers in the Central Valley, provide valuable insight into managing for multiple benefits in the landscape and an approach for assessing future land-management decisions.
Examining the Performance of Indian Exchange Traded Funds (ETFs

Directory of Open Access Journals (Sweden)

Naman SETHI

2016-11-01

Full Text Available Exchange traded funds (ETFs are known to be a highly attractive mean of investment in today’s financial markets. The present study is an attempt to explain the risk and return features of Indian ETFs and their trading and expense characteristics. The performance of ETFs is measured and compared with their underlying indices. It is found that they underperformed the indices, the reasons being they load their investors with extra risk than their underlying indices. Further, it is found that tracking error is having a positive relationship with expenses and risk of ETFs. Interestingly, the average number of trades and the lagged return of previous day do not affect the volume of shares. The study uses daily closing prices, intraday high and low prices and the volume of the traded shares of 10 ETFs listed on the National Stock Exchang for the period 1st July, 2010 to 30th June, 2015. The non-included ETFs suffer from the restrictions of non-availability of historical prices for at least five years.

A major trade-off between structural and photosynthetic investments operative across plant and needle ages in three Mediterranean pines.

Science.gov (United States)

Kuusk, Vivian; Niinemets, Ülo; Valladares, Fernando

2018-04-01

Pine (Pinus) species exhibit extensive variation in needle shape and size between juvenile (primary) and adult (secondary) needles (heteroblasty), but few studies have quantified the changes in needle morphological, anatomical and chemical traits upon juvenile-to-adult transition. Mediterranean pines keep juvenile needles longer than most other pines, implying that juvenile needles play a particularly significant role in seedling and sapling establishment in this environment. We studied needle anatomical, morphological and chemical characteristics in juvenile and different-aged adult needles in Mediterranean pines Pinus halepensis Mill., Pinus pinea L. and Pinus nigra J. F. Arnold subsp. salzmannii (Dunal) Franco hypothesizing that needle anatomical modifications upon juvenile-to-adult transition lead to a trade-off between investments in support and photosynthetic tissues, and that analogous changes occur with needle aging albeit to a lower degree. Compared with adult needles, juvenile needles of all species were narrower with 1.6- to 2.4-fold lower leaf dry mass per unit area, and had ~1.4-fold thinner cell walls, but needle nitrogen content per dry mass was similar among plant ages. Juvenile needles also had ~1.5-fold greater mesophyll volume fraction, ~3-fold greater chloroplast volume fraction and ~1.7-fold greater chloroplast exposed to mesophyll exposed surface area ratio, suggesting overall greater photosynthetic activity. Changes in needle traits were similar in aging adult needles, but the magnitude was generally less than the changes upon juvenile to adult transition. In adult needles, the fraction in support tissues scaled positively with known ranking of species tolerance of drought (P. halepensis > P. pinea > P. nigra). Across all species, and needle and plant ages, a negative correlation between volume fractions of mesophyll and structural tissues was observed, manifesting a trade-off between biomass investments in different needle functions. These
TRADING-OFF CONSTRAINTS IN THE PUMP SCHEDULING OPTIMIZATION OF WATER DISTRIBUTION NETWORKS

Directory of Open Access Journals (Sweden)

Gencer Genço\\u011Flu

2016-01-01

Full Text Available Pumps are one of the essential components of water supply systems. Depending of the topography, a water supply system may completely rely on pumping. They may consume non-negligible amount of water authorities' budgets during operation. Besides their energy costs, maintaining the healthiness of pumping systems is another concern for authorities. This study represents a multi-objective optimization method for pump scheduling problem. The optimization objective contains hydraulic and operational constraints. Switching of pumps and usage of electricity tariff are assumed to be key factors for operational reliability and energy consumption and costs of pumping systems. The local optimals for systems operational reliability, energy consumptions and energy costs are investigated resulting from trading-off pump switch and electricity tariff constraints within given set of boundary conditions. In the study, a custom made program is employed that combines genetic algorithm based optimization module with hydraulic network simulation software -EPANET. Developed method is applied on the case study network; N8-3 pressure zone of the Northern Supply of Ankara (Turkey Water Distribution Network. This work offers an efficient method for water authorities aiming to optimize pumping schedules considering expenditures and operational reliability mutually.
Evidence for a trade-off strategy in stone oak (Lithocarpus seeds between physical and chemical defense highlights fiber as an important antifeedant.

Directory of Open Access Journals (Sweden)

Xi Chen

Full Text Available Trees in the beech or oak family (Fagaceae have a mutualistic relationship with scatter-hoarding rodents. Rodents obtain nutrients and energy by consuming seeds, while providing seed dispersal for the tree by allowing some cached seeds to germinate. Seed predation and caching behavior of rodents is primarily affected by seed size, mechanical protection, macronutrient content, and chemical antifeedants. To enhance seed dispersal, trees must optimize trade-offs in investment between macronutrients and antifeedants. Here, we examine this important chemical balance in the seeds of tropical stone oak species with two substantially different fruit morphologies. These two distinct fruit morphologies in Lithocarpus differ in the degree of mechanical protection of the seed. For 'acorn' fruit, a thin exocarp forms a shell around the seed while for 'enclosed receptacle' (ER fruit, the seed is embedded in a woody receptacle. We compared the chemical composition of numerous macronutrient and antifeedant in seeds from several Lithocarpus species, focusing on two pairs of sympatric species with different fruit morphologies. We found that macronutrients, particularly total non-structural carbohydrate, was more concentrated in seeds of ER fruits while antifeedants, primarily fibers, were more concentrated in seeds of acorn fruits. The trade-off in these two major chemical components was more evident between the two sympatric lowland species than between two highland species. Surprisingly, no significant difference in overall tannin concentrations in the seeds was observed between the two fruit morphologies. Instead, the major trade-off between macronutrients and antifeedants involved indigestible fibers. Future studies of this complex mutualism should carefully consider the role of indigestible fibers in the foraging behavior of scatter-hoarding rodents.
A bi-population based scheme for an explicit exploration/exploitation trade-off in dynamic environments

Science.gov (United States)

Ben-Romdhane, Hajer; Krichen, Saoussen; Alba, Enrique

2017-05-01

Optimisation in changing environments is a challenging research topic since many real-world problems are inherently dynamic. Inspired by the natural evolution process, evolutionary algorithms (EAs) are among the most successful and promising approaches that have addressed dynamic optimisation problems. However, managing the exploration/exploitation trade-off in EAs is still a prevalent issue, and this is due to the difficulties associated with the control and measurement of such a behaviour. The proposal of this paper is to achieve a balance between exploration and exploitation in an explicit manner. The idea is to use two equally sized populations: the first one performs exploration while the second one is responsible for exploitation. These tasks are alternated from one generation to the next one in a regular pattern, so as to obtain a balanced search engine. Besides, we reinforce the ability of our algorithm to quickly adapt after cnhanges by means of a memory of past solutions. Such a combination aims to restrain the premature convergence, to broaden the search area, and to speed up the optimisation. We show through computational experiments, and based on a series of dynamic problems and many performance measures, that our approach improves the performance of EAs and outperforms competing algorithms.
Trade-off between Transcriptome Plasticity and Genome Evolution in Cephalopods.

Science.gov (United States)

Liscovitch-Brauer, Noa; Alon, Shahar; Porath, Hagit T; Elstein, Boaz; Unger, Ron; Ziv, Tamar; Admon, Arie; Levanon, Erez Y; Rosenthal, Joshua J C; Eisenberg, Eli

2017-04-06

RNA editing, a post-transcriptional process, allows the diversification of proteomes beyond the genomic blueprint; however it is infrequently used among animals for this purpose. Recent reports suggesting increased levels of RNA editing in squids thus raise the question of the nature and effects of these events. We here show that RNA editing is particularly common in behaviorally sophisticated coleoid cephalopods, with tens of thousands of evolutionarily conserved sites. Editing is enriched in the nervous system, affecting molecules pertinent for excitability and neuronal morphology. The genomic sequence flanking editing sites is highly conserved, suggesting that the process confers a selective advantage. Due to the large number of sites, the surrounding conservation greatly reduces the number of mutations and genomic polymorphisms in protein-coding regions. This trade-off between genome evolution and transcriptome plasticity highlights the importance of RNA recoding as a strategy for diversifying proteins, particularly those associated with neural function. PAPERCLIP. Copyright © 2017 Elsevier Inc. All rights reserved.
Habitat Fragmentation Intensifies Trade-Offs between Biodiversity and Ecosystem Services in a Heathland Ecosystem in Southern England.

Science.gov (United States)

Cordingley, Justine E; Newton, Adrian C; Rose, Robert J; Clarke, Ralph T; Bullock, James M

2015-01-01

While habitat fragmentation represents a major threat to global biodiversity, its impacts on provision of ecosystem services are largely unknown. We analysed biodiversity value and provision of multiple ecosystem services in 110 fragments of lowland heathland ecosystems in southern England, in which vegetation dynamics have been monitored for over 30 years. Decreasing fragment size was found to be associated with a decrease in biodiversity and recreational values, but an increase in relative carbon storage, aesthetic value and timber value. The trade-off between either biodiversity or recreational values with the other ecosystem services therefore became more pronounced as heathland size decreased. This was attributed to a higher rate of woody succession in smaller heathland fragments over the past three decades, and contrasting values of different successional vegetation types for biodiversity and provision of ecosystem services. These results suggest that habitat fragmentation can reduce the potential for developing "win win" solutions that contribute to biodiversity conservation while also supporting socio-economic development. Approaches to multi-purpose management of fragmented landscapes should therefore consider the potential trade-offs in ecosystem services and biodiversity associated with fragmentation, in order to make an effective contribution to sustainable development.
Interspecific Interactions and the Scope for Parent-Offspring Conflict: High Mite Density Temporarily Changes the Trade-Off between Offspring Size and Number in the Burying Beetle, Nicrophorus vespilloides.

Directory of Open Access Journals (Sweden)

Ornela De Gasperin

Full Text Available Parents have a limited amount of resources to invest in reproduction and commonly trade-off how much they invest in offspring size (or quality versus brood size. A negative relationship between offspring size and number has been shown in numerous taxa and it underpins evolutionary conflicts of interest between parents and their young. For example, previous work on vertebrates shows that selection favours mothers that produce more offspring, at the expense of individual offspring size, yet favours offspring that have relatively few siblings and therefore attain a greater size at independence. Here we analyse how this trade-off is temporarily affected by stochastic variation in the intensity of interspecific interactions. We examined the effect of the mite Poecilochirus carabi on the relationship between offspring size and number in the burying beetle, Nicrophorus vespilloides. We manipulated the initial number of mites in the reproductive event (by introducing either no mites, 4 mites, 10 mites, or 16 mites, and assessed the effect on the brood. We found a similar trade-off between offspring size and number in all treatments, except in the '16 mite' treatment where the correlation between offspring number and size flattened considerably. This effect arose because larvae in small broods failed to attain a high mass by dispersal. Our results show that variation in the intensity of interspecific interactions can temporarily change the strength of the trade-off between offspring size and number. In this study, high densities of mites prevented individual offspring from attaining their optimal weight, thus potentially temporarily biasing the outcome of parent-offspring conflict in favour of parents.
Electron and gamma-ray irradiated NTD Si p-n structures static and dynamic parameters trade-off

International Nuclear Information System (INIS)

Marchenko, I.G.; Zhdanovich, N.E.; Karas', V.I.

2005-01-01

The comparison of different radiation defects types influence on static and dynamic parameters trade-off of power diodes fabricated on neutron-transmutation doped silicon have been fulfilled. Various defects sets were introduced utilizing electron irradiation (E=6 MeV), gamma-ray Co 60 irradiation and electron irradiation and subsequent annealing at temperature 700 degrees centigrade. It is established that optimal trade-of between forward voltage drop and operation speed is achieved in case of electron irradiation and annealing. In this case recombination process is governed by defect with energy level near middle of forbidden gap (E c -0.53 eV). The results obtained indicate on possibility of using these defect recombination properties for speed control in production of power fast high-voltage devices on the base of neutron-transmutation doped silicon. (authors)
Trade Mechanism Selection in Markets with Frictions

OpenAIRE

Gabriele Camera; Alain Delacroix

2004-01-01

We endogenize the trade mechanism in a search economy with many homogenous sellers and many heterogeneous buyers of unobservable type. We study how heterogeneity and the traders' continuation values -- which are endogenous -- influence the sellers' choice of trade mechanism. Sellers trade off the probability of an immediate sale against the surplus expected from it, choosing whether to trade with everyone and how quickly. In equilibrium sellers may simply target one buyer type via non-negotia...
An Examination of Corporate Spin-Offs on Company Performance and Shareholder Value

OpenAIRE

Scicluna, Karl

2015-01-01

The aim of this study is to examine the implications of corporate spin-offs on company performance and shareholder value. The study uses both event study and accounting-based study methodologies to assess the stock price response of parent companies to the announcement of spin-offs, and to analyse the long-run operating performance of spin-offs for both parent and subsidiary companies. The study focuses on UK and US firms between 2001 and 2011. Evidence collected from the ev...
Defining Pathways and Trade-offs Toward Universal Health Coverage Comment on “Ethical Perspective: Five Unacceptable Trade-offs on the Path to Universal Health Coverage”

Directory of Open Access Journals (Sweden)

Stéphane Verguet

2016-07-01

Full Text Available The World Health Organization’s (WHO’s World Health Report 2010, “Health systems financing, the path to universal coverage,” promoted universal health coverage (UHC as an aspirational objective for country health systems. Yet, in addition to the dimensions of services and coverage, distribution of coverage in the population, and financial risk protection highlighted by the report, the consideration of the budget constraint should be further strengthened in the ensuing debate on resource allocation toward UHC. Beyond the substantial financial constraints faced by low- and middle-income countries, additional considerations, such as the geographical context, the underlying country infrastructure, and the architecture of health systems, determine the feasibility, effectiveness, quality and cost of healthcare delivery. Therefore, increased production and use of local evidence tied to the criteria of health benefits, equity, financial risk protection, and costs accompanying health delivery are needed so that to highlight pathways and acceptable trade-offs toward UHC.
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.
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.
Synergies, Trade-offs, and Losses of Ecosystem Services in Urban Regions: an Integrated Multiscale Framework Applied to the Leipzig-Halle Region, Germany

Directory of Open Access Journals (Sweden)

Dagmar Haase

2012-09-01

Full Text Available Because we have entered the 'millennium of the cities', urban ecological research needs to account for the provisions ecosystem services provide to urban regions. In urban areas, ecosystem service assessment studies need to account for the complex land use patterns, which change over relatively short periods of time. We discuss an analytical framework for the spatial and temporal integration of different ecosystem services in an urban region to determine synergies, trade-offs and losses, and we employ a case study in Leipzig-Halle, Germany. The following five ecosystem services, which are of special importance for urban areas, were selected: local climate regulation, recreation potential, biodiversity potential, food supply, and above-ground carbon storage. These services were analyzed from 1990 to 2006. Our results identified only slight increases in urbanization (1% or 3 km² and in mining restoration (-11 km². However, the detected land use changes led to synergies with biodiversity and climate regulation of > 50% of the total area, whereas trade-offs of approximately 60% were detected between variables such as climate regulation and recreation. Finally, we address both the opportunities and the challenges that were encountered in the integration study, specifically with respect to the application in land use planning.
Optimal strategy for a single-qubit gate and the trade-off between opposite types of decoherence

International Nuclear Information System (INIS)

Alicki, Robert; Horodecki, Michal; Horodecki, Ryszard; Horodecki, Pawel; Jacak, Lucjan; Machnikowski, Pawel

2004-01-01

We study reliable quantum-information processing (QIP) under two different types of environment. The first type is Markovian exponential decay, and the appropriate elementary strategy of protection of qubit is to apply fast gates. The second one is strongly non-Markovian and occurs solely during operations on the qubit. The best strategy is then to work with slow gates. If the two types are both present, one has to optimize the speed of gate. We show that such a trade-off is present for a single-qubit operation in a semiconductor quantum dot implementation of QIP, where recombination of exciton (qubit) is Markovian, while phonon dressing gives rise to the non-Markovian contribution
The influence of feeding on the evolution of sensory signals: a comparative test of an evolutionary trade-off between masticatory and sensory functions of skulls in southern African horseshoe bats (Rhinolophidae).

Science.gov (United States)

Jacobs, D S; Bastian, A; Bam, L

2014-12-01

The skulls of animals have to perform many functions. Optimization for one function may mean another function is less optimized, resulting in evolutionary trade-offs. Here, we investigate whether a trade-off exists between the masticatory and sensory functions of animal skulls using echolocating bats as model species. Several species of rhinolophid bats deviate from the allometric relationship between body size and echolocation frequency. Such deviation may be the result of selection for increased bite force, resulting in a decrease in snout length which could in turn lead to higher echolocation frequencies. If so, there should be a positive relationship between bite force and echolocation frequency. We investigated this relationship in several species of southern African rhinolophids using phylogenetically informed analyses of the allometry of their bite force and echolocation frequency and of the three-dimensional shape of their skulls. As predicted, echolocation frequency was positively correlated with bite force, suggesting that its evolution is influenced by a trade-off between the masticatory and sensory functions of the skull. In support of this, variation in skull shape was explained by both echolocation frequency (80%) and bite force (20%). Furthermore, it appears that selection has acted on the nasal capsules, which have a frequency-specific impedance matching function during vocalization. There was a negative correlation between echolocation frequency and capsule volume across species. Optimization of the masticatory function of the skull may have been achieved through changes in the shape of the mandible and associated musculature, elements not considered in this study. © 2014 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2014 European Society For Evolutionary Biology.
Intraspecific variation in aerobic and anaerobic locomotion: gilthead sea bream (Sparus aurata) and Trinidadian guppy (Poecilia reticulata) do not exhibit a trade-off between maximum sustained swimming speed and minimum cost of transport

Science.gov (United States)

Svendsen, Jon C.; Tirsgaard, Bjørn; Cordero, Gerardo A.; Steffensen, John F.

2015-01-01

Intraspecific variation and trade-off in aerobic and anaerobic traits remain poorly understood in aquatic locomotion. Using gilthead sea bream (Sparus aurata) and Trinidadian guppy (Poecilia reticulata), both axial swimmers, this study tested four hypotheses: (1) gait transition from steady to unsteady (i.e., burst-assisted) swimming is associated with anaerobic metabolism evidenced as excess post exercise oxygen consumption (EPOC); (2) variation in swimming performance (critical swimming speed; Ucrit) correlates with metabolic scope (MS) or anaerobic capacity (i.e., maximum EPOC); (3) there is a trade-off between maximum sustained swimming speed (Usus) and minimum cost of transport (COTmin); and (4) variation in Usus correlates positively with optimum swimming speed (Uopt; i.e., the speed that minimizes energy expenditure per unit of distance traveled). Data collection involved swimming respirometry and video analysis. Results showed that anaerobic swimming costs (i.e., EPOC) increase linearly with the number of bursts in S. aurata, with each burst corresponding to 0.53 mg O2 kg−1. Data are consistent with a previous study on striped surfperch (Embiotoca lateralis), a labriform swimmer, suggesting that the metabolic cost of burst swimming is similar across various types of locomotion. There was no correlation between Ucrit and MS or anaerobic capacity in S. aurata indicating that other factors, including morphological or biomechanical traits, influenced Ucrit. We found no evidence of a trade-off between Usus and COTmin. In fact, data revealed significant negative correlations between Usus and COTmin, suggesting that individuals with high Usus also exhibit low COTmin. Finally, there were positive correlations between Usus and Uopt. Our study demonstrates the energetic importance of anaerobic metabolism during unsteady swimming, and provides intraspecific evidence that superior maximum sustained swimming speed is associated with superior swimming economy and
Ecological trade-offs between jasmonic acid-dependent direct and indirect plant defences in tritrophic interactions.

Science.gov (United States)

Wei, Jianing; Wang, Lizhong; Zhao, Jiuhai; Li, Chuanyou; Ge, Feng; Kang, Le

2011-01-01

Recent studies on plants genetically modified in jasmonic acid (JA) signalling support the hypothesis that the jasmonate family of oxylipins plays an important role in mediating direct and indirect plant defences. However, the interaction of two modes of defence in tritrophic systems is largely unknown. In this study, we examined the preference and performance of a herbivorous leafminer (Liriomyza huidobrensis) and its parasitic wasp (Opius dissitus) on three tomato genotypes: a wild-type (WT) plant, a JA biosynthesis (spr2) mutant, and a JA-overexpression 35S::prosys plant. Their proteinase inhibitor production and volatile emission were used as direct and indirect defence factors to evaluate the responses of leafminers and parasitoids. Here, we show that although spr2 mutant plants are compromised in direct defence against the larval leafminers and in attracting parasitoids, they are less attractive to adult flies compared with WT plants. Moreover, in comparison to other genotypes, the 35S::prosys plant displays greater direct and constitutive indirect defences, but reduced success of parasitism by parasitoids. Taken together, these results suggest that there are distinguished ecological trade-offs between JA-dependent direct and indirect defences in genetically modified plants whose fitness should be assessed in tritrophic systems and under natural conditions. © The Authors (2010). Journal compilation © New Phytologist Trust (2010).
Trade-off between reproduction and lifespan of the rotifer Brachionus plicatilis under different food conditions.

Science.gov (United States)

Sun, Yunfei; Hou, Xinying; Xue, Xiaofeng; Zhang, Lu; Zhu, Xuexia; Huang, Yuan; Chen, Yafen; Yang, Zhou

2017-11-13

Phaeocystis globosa, one of the most typical red tide-forming species, is usually mixed in the food composition of rotifers. To explore how rotifers respond by adjusting life history strategy when feeding on different quality foods, we exposed the rotifer Brachionus plicatilis to cultures with 100% Chlorella, a mixture of 50% P. globosa and 50% Chlorella, or 100% P. globosa. Results showed that rotifers exposed to 100% Chlorella or to mixed diets produced more total offspring and had higher age-specific fecundity than those exposed to 100% P. globosa. Food combination significantly affected the net reproduction rates of rotifers. By contrast, rotifers that fed on 100% P. globosa or on mixed diets had a longer lifespan than those fed on 100% Chlorella. The overall performances (combining reproduction and lifespan together) of rotifers cultured in 100% Chlorella or mixed diets were significantly higher than those cultured in 100% P. globosa. In general, Chlorella favors rotifers reproduction at the cost of shorter lifespan, whereas P. globosa tends to extend the lifespan of rotifers with lower fecundity, indicating that trade-off exists between reproduction and lifespan under different food conditions. The present study also suggests that rotifers may have the potential to control harmful P. globosa.
A trade-off between precopulatory and postcopulatory trait investment in male cetaceans.

Science.gov (United States)

Dines, James P; Mesnick, Sarah L; Ralls, Katherine; May-Collado, Laura; Agnarsson, Ingi; Dean, Matthew D

2015-06-01

Mating with multiple partners is common across species, and understanding how individual males secure fertilization in the face of competition remains a fundamental goal of evolutionary biology. Game theory stipulates that males have a fixed budget for reproduction that can lead to a trade-off between investment in precopulatory traits such as body size, armaments, and ornaments, and postcopulatory traits such as testis size and spermatogenic efficiency. Recent theoretical and empirical studies have shown that if males can monopolize access to multiple females, they will invest disproportionately in precopulatory traits and less in postcopulatory traits. Using phylogenetically controlled comparative methods, we demonstrate that across 58 cetacean species with the most prominent sexual dimorphism in size, shape, teeth, tusks, and singing invest significantly less in relative testes mass. In support of theoretical predictions, these species tend to show evidence of male contests, suggesting there is opportunity for winners to monopolize access to multiple females. Our approach provides a robust dataset with which to make predictions about male mating strategies for the many cetacean species for which adequate behavioral observations do not exist. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

85Kr management trade-offs: a perspective to total radiation dose commitment

Energy Technology Data Exchange (ETDEWEB)

Mellinger, P.J.; Hoenes, G.R.; Brackenbush, L.W.; Greenborg, J.

1980-01-01

Radiological consequences arising from the trade-offs for /sup 85/Kr waste management from possible nuclear fuel resource recovery activities have been investigated. The reference management technique is to release all the waste gas to the atmosphere where it is diluted and dispersed. A potential alternative is to collect, concentrate, package and submit the gas to long-term storage. This study compares the radiation dose commitment to the public and to the occupationally exposed work force from these alternatives. The results indicate that it makes little difference to the magnitude of the world population dose whether /sup 85/Kr is captured and stored or chronically released to the environment. Further, comparisons of radiation exposures (for the purpose of estimating health effects) at very low dose rates to very large populations with exposures to a small number of occupationally exposed workers who each receive much higher dose rates may be misleading. Finally, cost studies (EPA 1976 and DOE 1979a) show that inordinate amounts of money will be required to lower this already extremely small 80-year cumulative world population dose of 0.05 mrem/person (<0.001% of natural background radiation for the same time period).
Attention failures versus misplaced diligence: separating attention lapses from speed-accuracy trade-offs.

Science.gov (United States)

Seli, Paul; Cheyne, James Allan; Smilek, Daniel

2012-03-01

In two studies of a GO-NOGO task assessing sustained attention, we examined the effects of (1) altering speed-accuracy trade-offs through instructions (emphasizing both speed and accuracy or accuracy only) and (2) auditory alerts distributed throughout the task. Instructions emphasizing accuracy reduced errors and changed the distribution of GO trial RTs. Additionally, correlations between errors and increasing RTs produced a U-function; excessively fast and slow RTs accounted for much of the variance of errors. Contrary to previous reports, alerts increased errors and RT variability. The results suggest that (1) standard instructions for sustained attention tasks, emphasizing speed and accuracy equally, produce errors arising from attempts to conform to the misleading requirement for speed, which become conflated with attention-lapse produced errors and (2) auditory alerts have complex, and sometimes deleterious, effects on attention. We argue that instructions emphasizing accuracy provide a more precise assessment of attention lapses in sustained attention tasks. Copyright © 2011 Elsevier Inc. All rights reserved.
Fitness Trade-Offs in Competence Differentiation of Bacillus subtilis.

Science.gov (United States)

Yüksel, Melih; Power, Jeffrey J; Ribbe, Jan; Volkmann, Thorsten; Maier, Berenike

2016-01-01

In the stationary phase, Bacillus subtilis differentiates stochastically and transiently into the state of competence for transformation (K-state). The latter is associated with growth arrest, and it is unclear how the ability to develop competence is stably maintained, despite its cost. To quantify the effect differentiation has on the competitive fitness of B. subtilis, we characterized the competition dynamics between strains with different probabilities of entering the K-state. The relative fitness decreased with increasing differentiation probability both during the stationary phase and during outgrowth. When exposed to antibiotics inhibiting cell wall synthesis, transcription, and translation, cells that differentiated into the K-state showed a selective advantage compared to differentiation-deficient bacteria; this benefit did not require transformation. Although beneficial, the K-state was not induced by sub-MIC concentrations of antibiotics. Increasing the differentiation probability beyond the wt level did not significantly affect the competition dynamics with transient antibiotic exposure. We conclude that the competition dynamics are very sensitive to the fraction of competent cells under benign conditions but less sensitive during antibiotic exposure, supporting the picture of stochastic differentiation as a fitness trade-off.
Canister storage building trade study. Final report

International Nuclear Information System (INIS)

Swenson, C.E.

1995-05-01

This study was performed to evaluate the impact of several technical issues related to the usage of the Canister Storage Building (CSB) to safely stage and store N-Reactor spent fuel currently located at K-Basin 100KW and 100KE. Each technical issue formed the basis for an individual trade study used to develop the ROM cost and schedule estimates. The study used concept 2D from the Fluor prepared ''Staging and Storage Facility (SSF) Feasibility Report'' as the basis for development of the individual trade studies
Canister storage building trade study. Final report

Energy Technology Data Exchange (ETDEWEB)

Swenson, C.E. [Westinghouse Hanford Co., Richland, WA (United States)

1995-05-01

This study was performed to evaluate the impact of several technical issues related to the usage of the Canister Storage Building (CSB) to safely stage and store N-Reactor spent fuel currently located at K-Basin 100KW and 100KE. Each technical issue formed the basis for an individual trade study used to develop the ROM cost and schedule estimates. The study used concept 2D from the Fluor prepared ``Staging and Storage Facility (SSF) Feasibility Report`` as the basis for development of the individual trade studies.
Trade-offs between competition and defense specialists among unicellular planktonic organisms: the "killing the winner" hypothesis revisited.

Science.gov (United States)

Winter, Christian; Bouvier, Thierry; Weinbauer, Markus G; Thingstad, T Frede

2010-03-01

A trade-off between strategies maximizing growth and minimizing losses appears to be a fundamental property of evolving biological entities existing in environments with limited resources. In the special case of unicellular planktonic organisms, the theoretical framework describing the trade-offs between competition and defense specialists is known as the "killing the winner" hypothesis (KtW). KtW describes how the availability of resources and the actions of predators (e.g., heterotrophic flagellates) and parasites (e.g., viruses) determine the composition and biogeochemical impact of such organisms. We extend KtW conceptually by introducing size- or shape-selective grazing of protozoans on prokaryotes into an idealized food web composed of prokaryotes, lytic viruses infecting prokaryotes, and protozoans. This results in a hierarchy analogous to a Russian doll, where KtW principles are at work on a lower level due to selective viral infection and on an upper level due to size- or shape-selective grazing by protozoans. Additionally, we critically discuss predictions and limitations of KtW in light of the recent literature, with particular focus on typically neglected aspects of KtW. Many aspects of KtW have been corroborated by in situ and experimental studies of isolates and natural communities. However, a thorough test of KtW is still hampered by current methodological limitations. In particular, the quantification of nutrient uptake rates of the competing prokaryotic populations and virus population-specific adsorption and decay rates appears to be the most daunting challenge for the years to come.
Design trade-off between spatial resolution and power consumption in CMOS biosensor circuit based on millimeter-wave LC oscillator array

Science.gov (United States)

Matsunaga, Maya; Kobayashi, Atsuki; Nakazato, Kazuo; Niitsu, Kiichi

2018-03-01

In this paper, we describe a trade-off between spatial resolution and power consumption in an LC oscillator-based CMOS biosensor, which can detect biomolecules by observing the resonance frequency shift due to changes in the complex permittivity of the biomolecules. The optimal operating frequency and improvement in the image resolution of the sensor output require a reduction in the size of the inductor. However, it is necessary to increase the transconductance of the cross-coupling transistor to achieve the oscillation condition, although the power consumption increases. We confirmed the trade-off between the spatial resolution and the power consumption of this sensor using SPICE simulation. A test chip was fabricated using a 65 nm CMOS process, and the transition in the peak frequency and the power consumption were measured. When the outer diameter of the inductor was 46 µm, the power consumption was 31.2 mW, which matched well with the simulation results.
Thermal sensitivity of immune function: evidence against a generalist-specialist trade-off among endothermic and ectothermic vertebrates

Science.gov (United States)

Butler, Michael W.; Stahlschmidt, Zachary R.; Ardia, Daniel R.; Davies, Scott; Davis, Jon; Guillette, Louis J.; Johnson, Nicholas; McCormick, Stephen D.; McGraw, Kevin J.; DeNardo, Dale F.

2013-01-01

Animal body temperature (Tbody) varies over daily and annual cycles, affecting multiple aspects of biological performance in both endothermic and ectothermic animals. Yet a comprehensive comparison of thermal performance among animals varying in Tbody (mean and variance) and heat production is lacking. Thus, we examined the thermal sensitivity of immune function (a crucial fitness determinant) in Vertebrata, a group encompassing species of varying thermal biology. Specifically, we investigated temperature-related variation in two innate immune performance metrics, hemagglutination and hemolysis, for 13 species across all seven major vertebrate clades. Agglutination and lysis were temperature dependent and were more strongly related to the thermal biology of species (e.g., mean Tbody) than to the phylogenetic relatedness of species, although these relationships were complex and frequently surprising (e.g., heterotherms did not exhibit broader thermal performance curves than homeotherms). Agglutination and lysis performance were positively correlated within species, except in taxa that produce squalamine, a steroidal antibiotic that does not lyse red blood cells. Interestingly, we found the antithesis of a generalist-specialist trade-off: species with broader temperature ranges of immune performance also had higher peak performance levels. In sum, we have uncovered thermal sensitivity of immune performance in both endotherms and ectotherms, highlighting the role that temperature and life history play in immune function across Vertebrata.
Evaluation of logistic performance indexes of Brazil in the international trade.

Directory of Open Access Journals (Sweden)

Rosane Nunes de Faria

2015-02-01

Full Text Available The importance of efficient logistics for trade growth is widely acknowledged. Literature has shown that better logistics performance is strongly associated with trade expansion, export diversification, ability to attract foreign direct investments, and economic growth. On the other hand, international trade represents a challenge to logistic operations in transporting and storing products. High logistic costs and low quality of services may be considered obstacles to international trade. This research aims to assess Brazil’s Logistics Performance Index (LPI in relation to its major competitors in international trade. The international trade data was collected from SECEX and COMTRADE, while the LPI was provided by the World Bank. Statistical techniques such as cluster analysis and multiple comparison tests of means have been applied to analyze the data. After using LPI index for the 39 competitors, it has been observed that Brazil occupies the 26th position in the rank of performers, behind South Africa, Kuwait and Saudi Arabia. The top performers are in general the leading exporters and importers worldwide (Germany, U.S.A., Japan and the Netherlands. Furthermore, they are the strongest competitors of Brazil in international trade. Thus, the competitiveness of Brazilian domestic firms depends crucially on a dynamic and competitive internal logistic environment in order to stand up to these countries. The results also indicate the bureaucracy as a major obstacle to the logistic performance of the country. The dimension Timeliness of Brazil is very close to the High Logistics Performance Group (HLPG while Customs is very close to the Low Logistics Performance Group (LLPG. Although Brazil has failed in its customs operations, there seems to be more credibility in Brazilian dealings. The main contribution of this paper is to reveal logistical aspects in which Brazil has shown large inefficiencies. The difference among the logistic performance
A fundamental trade-off in covalent switching and its circumvention by enzyme bifunctionality in glucose homeostasis.

Science.gov (United States)

Dasgupta, Tathagata; Croll, David H; Owen, Jeremy A; Vander Heiden, Matthew G; Locasale, Jason W; Alon, Uri; Cantley, Lewis C; Gunawardena, Jeremy

2014-05-09

Covalent modification provides a mechanism for modulating molecular state and regulating physiology. A cycle of competing enzymes that add and remove a single modification can act as a molecular switch between "on" and "off" and has been widely studied as a core motif in systems biology. Here, we exploit the recently developed "linear framework" for time scale separation to determine the general principles of such switches. These methods are not limited to Michaelis-Menten assumptions, and our conclusions hold for enzymes whose mechanisms may be arbitrarily complicated. We show that switching efficiency improves with increasing irreversibility of the enzymes and that the on/off transition occurs when the ratio of enzyme levels reaches a value that depends only on the rate constants. Fluctuations in enzyme levels, which habitually occur due to cellular heterogeneity, can cause flipping back and forth between on and off, leading to incoherent mosaic behavior in tissues, that worsens as switching becomes sharper. This trade-off can be circumvented if enzyme levels are correlated. In particular, if the competing catalytic domains are on the same protein but do not influence each other, the resulting bifunctional enzyme can switch sharply while remaining coherent. In the mammalian liver, the switch between glycolysis and gluconeogenesis is regulated by the bifunctional 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFK-2/FBPase-2). We suggest that bifunctionality of PFK-2/FBPase-2 complements the metabolic zonation of the liver by ensuring coherent switching in response to insulin and glucagon.
Comparative study on current trading system and online trading: the ...

African Journals Online (AJOL)

Comparative study on current trading system and online trading: the case of ... of online trading and factors affecting its feasibility of implementation in ECX. ... The study found that there is significant capacity problem with major skills gap with ...
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.
Purchasing and Operation planning of a firm from paints sector and their trade-off

Directory of Open Access Journals (Sweden)

Roger Augusto Luna

2016-11-01

Full Text Available Production lines must be flexible in order to fulfill organizational goals, but they need to be aligned with the demands of production and the level of service. The objective of this research is to analyze the trade-offs in the decision taken regarding the volumes to be produced and the need to meet the production demand established by the company, without disruption to operations. The primary data source was a company in the paint sector. The methodology used was based on a qualitative case-study approach, through interviews with the company’s logistics and operations managers, providing a more comprehensive understanding of the problems. The results of the field survey showed that the company needs to anticipate their purchases of imported raw materials and plan their production in advance, avoiding decisions on which product to produce first, generating stock that supports demand.
Allometry of individual reproduction and defense in eusocial colonies: A comparative approach to trade-offs in social sponge-dwelling Synalpheus shrimps.

Directory of Open Access Journals (Sweden)

Sarah L Bornbusch

Full Text Available Eusociality, one of the most complex forms of social organization, is thought to have evolved in several animal clades in response to competition for resources and reproductive opportunities. Several species of snapping shrimp in the genus Synalpheus, the only marine organisms known to exhibit eusociality, form colonies characterized by high reproductive skew, and aggressive territoriality coupled with cooperative defense. In eusocial Synalpheus colonies, individual reproduction is limited to female 'queens', whose fecundity dictates colony growth. Given that individual reproduction and defense are both energetically costly, individual and colony fitness likely depend on the optimal allocation of resources by these reproducing individuals towards these potentially competing demands. Synalpheus species, however, display varying degrees of eusociality, suggesting that reproducing females have adopted different strategies for allocation among reproduction and defense. Here, we use structural equation modeling to characterize the relationships between the allometry of queen reproductive capacity and defensive weaponry, and colony size in six eusocial Synalpheus species, estimating trade-offs between reproduction and defense. We document strong trade-offs between mass of the fighting claw (defense and egg number (reproduction in queens from weakly eusocial species, while the trade-off is reduced or absent in those from strongly eusocial species. These results suggest that in less cooperative species, intra-colony conflict selects for queen retention of weapons that have significant costs to fecundity, while reproducing females from highly eusocial species, i.e., those with a single queen, have been able to reduce the cost of weapons as a result of protection by other colony members.
Exploring trade-offs between carbon storage, yield and biodiversity in analog forestry. A case study in the Peruvian Amazon

Science.gov (United States)

Recanati, F.; Saini, M.; Guariso, G.; Melia, P.

2016-12-01

Creation and management of agro-ecosystems can considerably influence the greenhouse gas exchange between terrestrial ecosystems and atmosphere. This is especially evident for tropical areas, where the expansion of agricultural lands for monoculture is among the main causes of deforestation and consequent CO2 emissions. In these contexts, agro-ecological approaches, such as analog forestry, seem promising alternatives to intensive ones. Analog forestry is usually created for reforestation purposes through the combination of ecological succession and architecture of natural forests (i.e., inclusion of species from shrubs to higher trees). Besides provisioning a variety of food and medicinal products, they provide high levels of biodiversity (compared to other agricultural practices) and important ecosystem services, like carbon storage. Given the complexity of such agro-ecosystems, this study aims to estimate the quantity of carbon that can be stored in an analog forest as a function of its species composition. Consequently, trade-offs between performances in terms of carbon storage, productivity and biodiversity are explored. The analysis focuses on the Peruvian region of Madre de Dios, where native forest and its biodiversity is threatened by intensive agriculture. To quantify plant above- and belowground biomass and the related carbon content, we feed appropriate allometric models with plant morphological information gathered in the field. Relying on our database of productive plant species suitable for the region, we formulate an optimization problem aimed at the selection of plant population under different constraint systems. The latter are defined according to possible farmers' preferences (e.g., average profitability or multi-functionality). The analysis refers to the farm-scale and is performed over medium-term horizon (i.e., 40 years), in order to take into account important plant dynamics (species growth and the evolution of shade interaction
Parasitism and Physiological Trade-Offs in Stressed Capybaras

Science.gov (United States)

Eberhardt, Ayelen T.; Costa, Sebastián A.; Marini, M. Rocío; Racca, Andrea; Baldi, Cecilia J.; Robles, M. Rosario; Moreno, Pablo G.; Beldomenico, Pablo M.

2013-01-01

Parasites play a key role in regulating wildlife population dynamics, but their impact on the host appears to be context-dependent. Evidence indicates that a synergistic interaction between stress, host condition and parasites is implicated in this phenomenon, but more studies are needed to better understand this context-dependency. With the goal to assess the net effect of two types of chronic stress on various host-parasite interactions, we conducted an experiment in capybaras to evaluate the impact of food restriction and physical restraint on the infection intensity of specific gastrointestinal nematodes and coccidia, and how these stressors affected the growth, body condition, and some immuno-physiological parameters. Our hypothesis was that both forms of stress would result in an alteration in the host-parasite interactions, with deteriorated condition and reduced immunological investment leading to high parasite burdens and vice versa. Stressed capybaras had significantly higher coccidia infection intensities; but among individuals that were smaller, those stressed consistently showed lower helminth burdens than controls. Both stress treatments had a marked negative impact on growth and body condition, but concomitantly they had a significant positive effect on some components of the immune system. Our results suggest, on the one hand, that during prolonged periods of stress capybaras preventatively invest in some components of their immunity, such as innate humoural defenses and cells that combat helminths, which could be considered a stress-dependent prophylaxis. On the other hand, stress was found to cause greater infection intensities of protozoans but lower burdens of nematodes, indicating that the relationship between stress, physiological trade-offs and infection depends on the type of parasite in question. Moreover, both findings might be related in a causal way, as one of the immunological parameters enhanced in stressed capybaras is associated with
Trading Relationship Performance and Market Power in Food Supply Chains

DEFF Research Database (Denmark)

Xhoxhi, Orjon

The development of the agri-food industry has led to a considerable increase of intermediaries’ market power vis-à-vis farmers. There are studies and evidence that suggests that due to their power, intermediaries transfer risks and unexpected costs to farmers which compromise the innovation...... and livelihood. The overall objective of this PhD study was to investigate the intermediaries’ power over farmers and its effects on trading relationship performance between them. Two farms survey were conducted, the first one was carried out in the Adana region in Turkey and had an explorative focus aiming......), investigate how intermediaries’ power affects farmers-intermediaries trading relationship performance (paper 3) and analyse the determinants of contract farming and its effects on post-harvest losses (paper 4). The first paper investigates the determinants of intermediaries’ power over farmers’ margin related...
Trapped between two tails: trading off scientific uncertainties via climate targets

International Nuclear Information System (INIS)

Lemoine, Derek; McJeon, Haewon C

2013-01-01

Climate change policies must trade off uncertainties about future warming, about the social and ecological impacts of warming, and about the cost of reducing greenhouse gas emissions. We show that laxer carbon targets produce broader distributions for climate damages, skewed towards severe outcomes. However, if potential low-carbon technologies fill overlapping niches, then more stringent carbon targets produce broader distributions for the cost of reducing emissions, skewed towards high-cost outcomes. We use the technology-rich GCAM integrated assessment model to assess the robustness of 450 and 500 ppm carbon targets to each uncertain factor. The 500 ppm target provides net benefits across a broad range of futures. The 450 ppm target provides net benefits only when impacts are greater than conventionally assumed, when multiple technological breakthroughs lower the cost of abatement, or when evaluated with a low discount rate. Policy evaluations are more sensitive to uncertainty about abatement technology and impacts than to uncertainty about warming. (letter)
Trapped between two tails: trading off scientific uncertainties via climate targets

Science.gov (United States)

Lemoine, Derek; McJeon, Haewon C.

2013-09-01

Climate change policies must trade off uncertainties about future warming, about the social and ecological impacts of warming, and about the cost of reducing greenhouse gas emissions. We show that laxer carbon targets produce broader distributions for climate damages, skewed towards severe outcomes. However, if potential low-carbon technologies fill overlapping niches, then more stringent carbon targets produce broader distributions for the cost of reducing emissions, skewed towards high-cost outcomes. We use the technology-rich GCAM integrated assessment model to assess the robustness of 450 and 500 ppm carbon targets to each uncertain factor. The 500 ppm target provides net benefits across a broad range of futures. The 450 ppm target provides net benefits only when impacts are greater than conventionally assumed, when multiple technological breakthroughs lower the cost of abatement, or when evaluated with a low discount rate. Policy evaluations are more sensitive to uncertainty about abatement technology and impacts than to uncertainty about warming.
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

Some links on this page may take you to non-federal websites. Their policies may differ from this site.