scholarly journals Trait-specific trade-offs prevent niche expansion in two parasites

2019 ◽  
Author(s):  
Eva J. P. Lievens ◽  
Yannis Michalakis ◽  
Thomas Lenormand
Keyword(s):  
Experimental Work ◽  
Host Species ◽  
Experimental Evolution ◽  
Brine Shrimp ◽  
Spore Production ◽  
The Other ◽  
Host Specialization ◽  
Trade Off ◽  
Trade Offs ◽  
Evolution Approach

AbstractThe evolution of host specialization has been studied intensively, yet it is still often difficult to determine why parasites do not evolve broader niches – in particular when the available hosts are closely related and ecologically similar. Here, we used an experimental evolution approach to study the evolution of host specialization, and its underlying traits, in two sympatric parasites: Anostracospora rigaudi and Enterocytospora artemiae, microsporidians infecting the brine shrimp Artemia franciscana and Artemia parthenogenetica. In the field, both parasites regularly infect both hosts, yet experimental work has revealed that they are each partially specialized. We serially passaged the parasites on one, the other, or an alternation of the two hosts; after ten passages, we assayed the infectivity, virulence, and spore production rate of the evolved lines. In accordance with previous studies, A. rigaudi maintained a higher fitness on A. parthenogenetica, and E. artemiae on A. franciscana, in all treatments. The origin of this specialization was not infectivity, which readily evolved and traded off weakly between the host species for both parasites. Instead, the overall specialization was caused by spore production, which did not evolve in any treatment. This suggests the existence of a strong trade-off between spore production in A. franciscana and spore production in A. parthenogenetica, making this trait a barrier to the evolution of generalism in this system. This study highlights that the shape of between-host trade-offs can be very heterogeneous across parasite traits, so that only some traits are pivotal to specialization.

Role of Spatial Configuration in Commuting Trade-Offs of Two-Worker Households: A Case Study in the Greater Toronto Area

2018 ◽  
Vol 2672 (3) ◽  
pp. 69-79
Author(s):  
Saidal Akbari ◽  
Khandker Nurul Habib
Keyword(s):  
Spatial Configuration ◽  
Stated Preference ◽  
The Other ◽  
Trade Off ◽  
Greater Toronto Area ◽  
Home Location ◽  
Trade Offs ◽  
Home Work ◽  
The Difference ◽  
Commute Distance

This research investigates the commuting trade-offs between individuals in two-worker households with home and work locations in the Greater Toronto Area (GTA). A commuting trade-off occurs when a home relocation results in one worker incurring a higher commute distance for the other worker to work closer to the home location. This research uses stated preference data and multilevel modeling to demonstrate that two-worker households adjust their home–work spatial configuration which results in commuting trade-offs between individuals. This research uses the angle between the two workplaces, measured at the home location, as a variable in its empirical model. This variable is a descriptor of the home–work spatial configuration and a predictor of total household commute distance. The modeling results indicate an inverse relationship between total household commute distance and the difference between individual commutes. This suggests that individuals in two-worker households trade off their individual commute distances and, in that process, reduce total household commute distance. A key policy implication arising from this research relates to the jobs–housing balance within a catchment area. Two-worker households have been regarded as a hindrance to achieving jobs–housing balance as the two work locations present a constraint in relocating the home near both work locations. However, as this research shows, workers will trade off their individual commute distances such that a home relocation results in a shorter commute distance for one worker and longer commute distance for the other.

Modelling WSNs Using OMNeT++

2012 ◽  
pp. 319-340 ◽  
Author(s):  
Erwin Anggadjaja ◽  
Ian V. McLoughlin
Keyword(s):  
Wireless Sensor Networks ◽  
System Design ◽  
Failure Modes ◽  
The Other ◽  
Wireless Sensor ◽  
Trade Off ◽  
Sensing Systems ◽  
Trade Offs ◽  
Comprehensive Comparison ◽  
Potential Failure

Wireless sensor networks (WSNs) have been used to observe and monitor many environments for specific purposes and in many ways over the past few years. A number of operational trade-offs are possible when planning a WSN, influencing coverage, bandwidth, redundancy, lifetime, expandability, and so on. However, for systems in potentially hazardous locations or those experiencing restricted access, system unreliability tends to be the greatest operational concern. In the process of creating reliable WSNs for hazardous locations, it is highly desirable to ensure both an accurate and a reliable system design prior to deployment, and with as little unnecessary trade-off as possible. Especially as sensing systems become larger and more complex, and potential failure modes increase, this becomes more difficult to achieve. In an attempt to answer the question of reliability assurance, the authors investigate WSNs in the context of accurate and fast modelling of such networks. A comprehensive comparison of three modelling tools (ns-2, OPNET, and OMNeT++) is explored in this chapter, concluding that OMNeT++ is worthy of study as an alternative to the other two more established tools. As an illustration of the use of OMNeT++, two modelling schemes are simulated and compared against the theory to determine both bit-level correctness, but also to demonstrate ease of modelling and analysis.

scholarly journals Resource Management for Improving Overall Reliability of Multi-Processor Systems-on-Chip

2020 ◽  
pp. 233-246
Author(s):  
Yue Ma ◽  
Junlong Zhou ◽  
Thidapat Chantem ◽  
Robert P. Dick ◽  
X. Sharon Hu
Keyword(s):  
Soft Error ◽  
The Other ◽  
Transient Faults ◽  
Trade Off ◽  
Permanent Faults ◽  
Trade Offs ◽  
Systems On Chip ◽  
Lifetime Reliability ◽  
On Chip ◽  
Overall Reliability

AbstractMulti-processor systems on a chip (MPSoCs) are widely deployed in real-time embedded systems. In such systems, soft-error reliability (caused by transient faults) and lifetime reliability (caused by permanent faults) are both imperative design concerns. Most existing work considers only one of the two classes of faults. Unfortunately, techniques that increase one may adversely impact the other. Achieving high overall reliability requires a trade-off of soft-error reliability and lifetime reliability. In this chapter, we first introduce concepts and models associated with the two reliability metrics, then present two techniques that optimize them separately. Finally, we show how to make appropriate trade-offs using two case studies involving “big–little” type MPSoCs and CPU–GPU integrated MPSoCs.

scholarly journals I alternate therefore I generalize: how the intrinsic resistance risk of fungicides counterbalances their durability

2021 ◽  
Author(s):  
Agathe Ballu ◽  
Philomene Despreaux ◽  
Clementine Duplaix ◽  
Anne Deredec ◽  
Florence Carpentier ◽  
...  
Keyword(s):  
Experimental Evolution ◽  
Selection Pressure ◽  
Resistance Management ◽  
Intrinsic Resistance ◽  
Zymoseptoria Tritici ◽  
Trade Off ◽  
Resistance Risk ◽  
Resistance Evolution ◽  
Evolution Of Resistance ◽  
Evolution Approach

The evolution of resistance to pesticides is a major burden in agriculture. Resistance management involves maximizing selection pressure heterogeneity, particularly by combining active ingredients with different modes of action. We tested the hypothesis that alternation may delay the build-up of resistance not only by spreading selection pressure over longer periods, but also by decreasing the rate of evolution of resistance to alternated fungicides, by applying an experimental evolution approach to the economically important crop pathogen Zymoseptoria tritici. Our results show that alternation is either neutral or slows the evolution of resistance, relative to continuous fungicide use, but results in higher levels of generalism in evolved lines. We demonstrate that the relative risk of resistance intrinsic to fungicide alternation probably underlies a trade-off between the number of fungicides and the frequency of alternation. This trade-off is also dynamic over the course of resistance evolution. These findings open up new possibilities for tailoring resistance management effectively while optimizing interplay between alternation components.

scholarly journals Nuclear arms races: experimental evolution for mating success in the mushroom-forming fungus Schizophyllum commune

2018 ◽  
Author(s):  
Bart P. S. Nieuwenhuis ◽  
Duur K. Aanen
Keyword(s):  
Sexual Selection ◽  
Mating Success ◽  
Experimental Evolution ◽  
Schizophyllum Commune ◽  
Spore Production ◽  
Pollen Competition ◽  
Male Reproductive Success ◽  
Competitive Fitness ◽  
Trade Offs ◽  
The One

SummaryWhen many gametes compete to fertilize a limited number of compatible gametes, sexual selection will favour traits that increase competitive success during mating. In animals and plants, sperm and pollen competition have yielded many interesting adaptations for improved mating success. In fungi, similar processes have not been shown directly yet. We test the hypothesis that sexual selection can increase competitive fitness during mating, using experimental evolution in the mushroom-forming fungus Schizophyllum commune (Basidiomycota). Mating in mushroom fungi occurs by donation of nuclei to a mycelium. These fertilizing ‘male’ nuclei migrate through the receiving ‘female’ mycelium. In our setup, an evolving population of nuclei was serially mated with a non-evolving female mycelium for 20 sexual generations. From the twelve tested evolved lines, four had increased and one had decreased fitness relative to an unevolved competitor. Even though only two of those five remained significant after correcting for multiple comparisons, for all five lines we found a correlation between the efficiency with which the female mycelium is accessed and fitness, providing additional circumstantial evidence for fitness change in those five lines. In two lines, fitness change was also accompanied by increased spore production. The one line with net reduced competitive fitness had increased spore production, but reduced fertilisation efficiency. We did not find trade-offs between male reproductive success and other fitness components. We compare these findings with examples of sperm and pollen competition and show that many similarities between these systems and nuclear competition in mushrooms exist.

scholarly journals Trade-Offs in Competitive Transport Operations

Economies ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 56 ◽  
Author(s):  
Usman Akbar ◽  
Akash Kumar ◽  
Hameed Khan ◽  
Muhammad Asif Khan ◽  
Khansa Parvaiz ◽  
...  
Keyword(s):  
Road Transport ◽  
Sustainable Growth ◽  
The Other ◽  
Transport Infrastructure ◽  
Infrastructure Development ◽  
Sustainable Transport ◽  
Trade Off ◽  
Competitive Edge ◽  
Trade Offs ◽  
In Transit

One of the goals of developing a transport corridor is to promote socio-economic development by improving connectivity and sustainable transport operations, which largely depends on the operational strategy. Trade-off policies can be important tools for gaining the competitive advantage of road transport corridors, and thus, help facilitate sustainable growth and welfare. This article uses a case-based approach to observe the trade-offs in the first phase of transport infrastructure development, and then, in the second stage, further explores the trade-off variables in the transport operations strategy under the China-Pakistan Economic Corridor (CPEC). The results from the three cases of the parallel route system of the CPEC indicate that trade-off is an easily understandable and applicable method, which can foresee the operational gains or compromises for significant welfare of the regions. The implications of the trade-off are two fold, first is the “importance” of the trade-off, which is related to its impact on operational competitiveness. The other is the “sensitivity” of the trade-off, in terms of the change that will be caused to one variable when changing the other. The trade-off concept can be used for several landlocked transport corridors to achieve a competitive edge in transit trade.

Sex or survival: trade-offs between quality and quantity of life.

1991 ◽  
Vol 9 (2) ◽  
pp. 328-334 ◽  
Author(s):  
P A Singer ◽  
E S Tasch ◽  
C Stocking ◽  
S Rubin ◽  
M Siegler ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Clinical Practice ◽  
Survival Rate ◽  
The Other ◽  
Localized Prostate Cancer ◽  
Term Survival ◽  
Trade Off ◽  
Level Of Education ◽  
Trade Offs

Patients with localized prostate cancer may be treated with either surgery (radical prostatectomy) or radiotherapy. Although controversial, many physicians believe that surgery offers a higher survival rate. However, the surgical treatment may also produce a higher rate of sexual impotency. Our study assessed how men value survival and sexual potency when asked to trade off one for the other. Using the treatment-choice technique, we interviewed 50 men aged 45 to 70 years without known prostate cancer. At hypothetical rates of survival (90% at 5 years for surgery) and impotency (90% for surgery and 40% for radiotherapy) representing published estimates, 32% of respondents were unwilling to trade off any survival, but 68% were willing to trade off a 10% or greater advantage in 5-year survival (by choosing radiotherapy) to maintain sexual potency. The median 5-year survival traded off was 10% (range, 0% to 80%). Willingness to trade off survival for sexual potency was significantly related to level of education, but not to age, interest in sex, frequency of sexual intercourse, or ability to achieve erection. We conclude that some men may choose treatment with lower long-term survival to increase their chance of remaining sexually potent. Because these men may be difficult to identify in clinical practice, physicians should thoroughly discuss both surgery and radiotherapy options with patients who have localized prostate cancer.

scholarly journals The Two Margin Problem in Insurance Markets

2021 ◽  
pp. 1-46
Author(s):  
Michael Geruso ◽  
Timothy J. Layton ◽  
Grace McCormack ◽  
Mark Shepard
Keyword(s):  
Theoretical Framework ◽  
The Other ◽  
Insurance Markets ◽  
Extensive Margin ◽  
Intensive Margin ◽  
Sufficient Statistics ◽  
Trade Off ◽  
Trade Offs ◽  
Using Data

Abstract Insurance markets often feature consumer sorting along both an extensive margin (whether to buy) and an intensive margin (which plan to buy). We present a new graphical theoretical framework that extends a workhorse model to incorporate both selection margins simultaneously. A key insight from our framework is that policies aimed at addressing one margin of selection often involve an economically meaningful trade-off on the other margin in terms of prices, enrollment, and welfare. Using data fromMassachusetts, we illustrate these trade-offs in an empirical sufficient statistics approach that is tightly linked to the graphical framework we develop.

scholarly journals Experimental evolution of parasite life-history traits in Strongyloides ratti (Nematoda)

2007 ◽  
Vol 274 (1617) ◽  
pp. 1467-1474 ◽  
Author(s):  
Steve Paterson ◽  
Rebecca Barber
Keyword(s):  
Life History ◽  
Experimental Evolution ◽  
Life History Traits ◽  
Evolutionary Ecology ◽  
Response To Selection ◽  
Trade Off ◽  
Density Dependent ◽  
Conspecific Density ◽  
Trade Offs ◽  
General Prediction

Evolutionary ecology predicts that parasite life-history traits, including a parasite's survivorship and fecundity within a host, will evolve in response to selection and that their evolution will be constrained by trade-offs between traits. Here, we test these predictions using a nematode parasite of rats, Strongyloides ratti , as a model. We performed a selection experiment by passage of parasite progeny from either early in an infection (‘fast’ lines) or late in an infection (‘slow’ lines). We found that parasite fecundity responded to selection but that parasite survivorship did not. We found a trade-off mediated via conspecific density-dependent constraints; namely, that fast lines exhibit higher density-independent fecundity than slow lines, but fast lines suffered greater reduction in fecundity in the presence of density-dependent constraints than slow lines. We also found that slow lines both stimulate a higher level of IgG1, which is a marker for a Th2-type immune response, and show less of a reduction in fecundity in response to IgG1 levels than for fast lines. Our results confirm the general prediction that parasite life-history traits can evolve in response to selection and indicate that such evolutionary responses may have significant implications for the epidemiology of infectious disease.

Dual Goals for Speed and Accuracy on the Same Performance Task

2012 ◽  
Vol 11 (3) ◽  
pp. 118-126 ◽  
Author(s):  
Olive Emil Wetter ◽  
Jürgen Wegge ◽  
Klaus Jonas ◽  
Klaus-Helmut Schmidt
Keyword(s):  
Memory Scanning ◽  
Performance Task ◽  
Performance Tasks ◽  
Trade Off ◽  
Test Experiment ◽  
Trade Offs ◽  
New Finding ◽  
Sternberg Paradigm ◽  
Speed Accuracy ◽  
Speed And Accuracy

In most work contexts, several performance goals coexist, and conflicts between them and trade-offs can occur. Our paper is the first to contrast a dual goal for speed and accuracy with a single goal for speed on the same task. The Sternberg paradigm (Experiment 1, n = 57) and the d2 test (Experiment 2, n = 19) were used as performance tasks. Speed measures and errors revealed in both experiments that dual as well as single goals increase performance by enhancing memory scanning. However, the single speed goal triggered a speed-accuracy trade-off, favoring speed over accuracy, whereas this was not the case with the dual goal. In difficult trials, dual goals slowed down scanning processes again so that errors could be prevented. This new finding is particularly relevant for security domains, where both aspects have to be managed simultaneously.

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