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The growing need for stronger and more ductile structural materials has spurred an intense search for innovative, high-performance alloys. Traditionally, alloys face a pervasive trade-off: high strength often comes at the expense of ductility and vice versa. The advent of high-entropy alloys (HEAs) offering both high strength and ductility has transformed this landscape. In this work, we discuss the deformation mechanisms of HEAs, examine the foundations of the strength-ductility trade-off, and explore approaches for designing HEAs to surmount this limitation. Furthermore, we analyze the factors that govern HEA-deformation performance, which in turn influence the HEA design. We also propose a perspective on future research directions concerning the mechanical behavior of HEAs, highlighting potential breakthroughs and novel strategies to advance the field. [ABSTRACT FROM AUTHOR]

In this paper, the finite-time and fixed-time synchronization problems of multi-layer networks are studied. In order to achieve the synchronization, two novel switching controllers are proposed and the effectiveness is verified by the Lyapunov stability theory. Moreover, the upper bound of time and energy costs are estimated. Specifically, the results show that increasing the synchronization speed will inevitably increase the consumption of control energy, which means there is a trade-off between time and energy costs. Therefore, an index function is given to quantify the time and energy costs, and it is found that adjusting the parameters can minimize the total cost. Finally, the theoretical results are verified by some numerical simulations. [ABSTRACT FROM AUTHOR]

One of the major challenges that populations have to face is vulnerability to water: lack of water, flooding, pollution, hazard sensitivity and coping capacity. Owing to economic, social and environmental inequalities, this paper focuses on water-related vulnerabilities in the Metropolitan Region of Santiago (RMS) in Chile. Our main objective is to understand, through mapping, the multiscalar logics of water vulnerability. This study is carried out at two scales: at the regional level (RMS), we proceed with open access municipal statistical data and maps, while at the local level, a more detailed analysis focusing on the Chacabuco Province is based on the same type of data but with either a higher spatial resolution (census districts) or a spatially more intensive data processing in order to take into account intra-municipal differences. In this way, we put into perspective the discourse developed in the Chilean media and by the inhabitants of Chacabuco Province regarding the province as an environmental ‘sacrifice zone’ for the RMS. The vulnerability maps are carried out at different scales in a simple and reproducible way by multi-criteria evaluation (MCE). The results confirm the hypothesis of a sacrifice zone and show that high-resolution data and adequate data processing give, on average, lower vulnerability scores than using only statistical data on the municipal level. The results provide a cartographic decision support for stakeholders. Limitations of the study are discussed and required further research is pointed out. [ABSTRACT FROM AUTHOR]

Extensive multi-criterion sorting (MCS) methods have been developed to address problems encountered in real-world scenarios. Nevertheless, these methods did not take into account the reliability of the information given by experts, and neglected the preferences of decision-makers when calculating the comprehensive performances of alternatives. To overcome these limitations, this paper proposes a double normalization-based multiple aggregation sorting method with Z-numbers (Z-DNMASort), which can depict both the reliability and uncertainty of any available information. The method considers both quantitative and qualitative criteria in forms of benefit, cost or target types in the sorting process, and also considers the reliability of information given by experts. Furthermore, this method takes into account three aggregation techniques to reflect the preferences of decision-makers when calculating the comprehensive performances of alternatives. A case study regarding battery electric vehicle (BEV) evaluation is given to validate the proposed method. The paper concludes by providing a comprehensive analysis and discourse on the proposed method. [ABSTRACT FROM AUTHOR]

For the rapidly developing unmanned aerial vehicle (UAV) swarm, the system-of-systems (SoS) oriented design is a prospective conceptual design methodology due to the competence for complex mission requirements and subsystems interactions. In the SoS oriented design, the subsystems performance trade-off is the basis of design decisions. In the trade-off for surveillance missions, most previous works do not consider track reporting and mainly focus on the design of platforms. An improved method for the subsystems performance trade-off in the SoS oriented UAV swarm design is proposed. Within an improved design framework with subsystems disaggregation, this method is characterized by treating platforms, sensors, and communications as equally important subsystems, integrating operational strategies into the trade-off, and enabling the trade-off for track reporting. Those advantages are achieved by a behavior-based modular model structure for agent-based operational modeling and simulation. In addition, a method of analyzing the bounds of the communication range is also presented. Simulation experiments are conducted by using precision-based simulation replication rules and surrogate modeling methods. The results demonstrate the effectiveness of the proposed method, and show that the configuration of area partitioning changes the trade space of subsystems performances, indicating the necessity of integrating operational strategies into the conceptual design. [ABSTRACT FROM AUTHOR]

Why some parasites evolve and maintain extreme levels of virulence is a question that remains largely unanswered. A body of theory predicts that parasites that form long-lived spores able to persist in the environment evolve higher virulence, known as the sit and wait hypothesis. Such parasites can obliterate their local host population and wait in the environment for further hosts to arrive, reducing some of the costs of high virulence. On the other hand, some models predict the opposite to be true, that virulence and environmental persistence are both costly and traded off, the resource allocation hypothesis. I conducted a meta-analysis on published data on the relationship between environmental persistence and virulence collected to date. I first examined all data available to date and then conducted a smaller analysis focussing on just those studies testing the specific predictions of the sit and wait hypothesis. Empirical work supports both hypotheses; however, the direction of the effect is largely associated with parasite type. In both analyses, viruses tend to show evidence of resource allocation trade-offs, these traits are positively correlated in bacterial and fungal parasites. [ABSTRACT FROM AUTHOR]

Physical scarcity of freshwater is often given as the reason for water shortages, but it is usually its management that can either create or resolve the problem. This will be illustrated by the case of Barbados. The water management issues are typical of many small island states, some of which are particularly vulnerable to water scarcity, especially in the context of climate change. Barbados experiences extended interruptions in the water supply, mainly in northern and eastern parishes. Supplies of freshwater are relatively sparse, but it will be argued that it is the policy regime that ensures that water is inefficiently supplied, allocated and used, and so is the primary cause of supply interruptions. The objectives of this paper are to establish a theoretical framework for sustainable water resource management and frame a strategy for Barbados which reconciles demand and supply of water while taking into account environmental, economic and social interests. The mixed methodology involved semistructured interviews of policy makers and practitioners from the water, tourism, agriculture and planning sectors, as well as a household survey. [ABSTRACT FROM AUTHOR]

One key potential explanation for the evolution of cooperation is conditional cooperation. This allows cooperation to evolve for cooperators who switch their behavior on the basis of information about the opponent's behavior or reputation. However, information about the opponent's behavior or reputation is sometimes unavailable, and previous studies have assumed that a player cooperates with some default probability when no information about the opponent's previous behavior or reputation is available. This default probability has been interpreted as the player's “optimism”. Here, we make use of the fact that even if a player cannot observe the opponent's previous behavior or reputation, he may still condition his future behavior based on his own past behavior and in such a case, he can behave persistently. In this paper, we especially consider the case where information about the opponent's “behavior” is sometimes absent and the iterated prisoner's dilemma game between the same two individuals is played. Here, we examine the evolution of strategies that can refer to the own behavior in the previous round. Using evolutionarily stable strategy (ESS) analysis and analyzing replicator dynamics, we find that conditioning his future behavior based on his own past behavior is beneficial for the evolution. Persistence facilitates the evolution of cooperation. [ABSTRACT FROM AUTHOR]

Parental behaviors that vary by sex and breeding stage facilitate the survival of offspring in birds. Females invest in reproducing according to the level of direct and/or indirect benefits provided by males. Males face trade-offs from defending territories or nests, providing for the young, and seeking additional mating opportunities. We examined whether post-mating sexual behaviors such as courtship display and nest-building were associated with reproductive investments made by males and females in the current study. The oriental stork ( Ciconia boyciana) is known as a solitary breeder that nests in tall trees and provides biparental care with long post-hatching development. We filmed parental behaviors in seven stork pairs in captivity for 655 hours (245 hours during nest-building, 218 hours during incubation, 328 hours during nestling, and 192 hours during the fledgling period). We found that paired mating behaviors such as synchronous allopreening and bill-clattering were highly skewed to the pre-incubation period. Males participated in nest-building more than females although both sexes shared similar parental care during the incubation and nestling period. Male nest-building was negatively correlated with male nest attentiveness only during the nestling period. Our results suggest that male oriental storks with higher nest-building effort might spend more time taking precautions against conspecific intruders or nest predators near the nests with chicks while the females were attending the nests in the form of biparental care. [ABSTRACT FROM AUTHOR]

Among beetles, thousands of species develop horns, the size of which is often extraordinarily disproportionate with respect to body size. The Scarabaeidae is the family in which horned species are most predominant, but other families, such as the Geotrupidae (dor beetles), also show remarkable horns, although in a more limited number of species. Horn expression mechanisms are well documented in Scarabaeidae but, despite the wealth of studies on this family, the horn morphological pattern of the Geotrupidae, to our knowledge, has never been investigated. In this paper, we describe for the first time the horn expression pattern in a dor beetle. As a study species, we chose Ceratophyus rossii, an Italian endemic dor beetle of the protected Mediterranean maquis in Tuscany, which shows remarkable head and pronotal horns in males and a notable cephalic horn in females. We identified and modeled shape and size horn patterns combining traditional and geometric morphometric approaches. We discuss the results in the wider landscape of developmental models described for other, more well-characterized, scarab beetles. [ABSTRACT FROM AUTHOR]

We surveyed nine populations of the three-spined stickleback infected by the diphyllobothriidean cestode Schistocephalus solidus from south-central Alaska for two apparent forms of tolerance to infection in females capable of producing egg clutches notwithstanding large parasite burdens. Seven populations exhibited fecundity reduction, whereas two populations showed fecundity compensation. Our data suggest that fecundity reduction, a side effect resulting from nutrient theft, occurs in two phases of host response influenced by the parasite : host body mass (BM) ratio. The first is significantly reduced ovum mass without significant reduction in clutch size, and the second one involves significant reductions in both ovum mass and clutch size. Thus, ovum mass of host females who are functionally being starved through nutrient theft seems to be more readily influenced by parasitism and, therefore, decreased before clutch size is reduced. This inference is consistent with expectations based on the biology of and effect of feeding ration on reproduction in stickleback females. Fecundity compensation appears to be uncommon among populations of three-spined stickleback in Alaska and rare among populations throughout the northern hemisphere. Fecundity reduction seems to be common, at least among stickleback populations in Alaska. [ABSTRACT FROM PUBLISHER]

Parasitic helminths are ubiquitous in most host, including human, populations. Helminths often alter the likelihood of infection and disease progression of coinfecting microparasitic pathogens (viruses, bacteria, protozoa), and there is great interest in incorporating deworming into control programmes for many major diseases (e.g. HIV, tuberculosis, malaria). However, such calls are controversial; studies show the consequences of deworming for the severity and spread of pathogens to be highly variable. Hence, the benefits of deworming, although clear for reducing the morbidity due to helminth infection per se, are unclear regarding the outcome of coinfections and comorbidities. I develop a theoretical framework to explore how helminth coinfection with other pathogens affects host mortality and pathogen spread and evolution under different interspecific parasite interactions. In all cases the outcomes of coinfection are highly context-dependent, depending on the mechanism of helminth-pathogen interaction and the quantitative level of helminth infection, with the effects of deworming potentially switching from beneficial to detrimental depending on helminth burden. Such context-dependency may explain some of the variation in the benefits of deworming seen between studies, and highlights the need for obtaining a quantitative understanding of parasite interactions across realistic helminth infection ranges. However, despite this complexity, this framework reveals predictable patterns in the effects of helminths that may aid the development of more effective, integrated management strategies to combat pathogens in this coinfected world. [ABSTRACT FROM PUBLISHER]

The range of hosts used by a parasite is influenced by macro-evolutionary processes (host switching, host–parasite co-evolution), as well as ‘encounter filters’ and ‘compatibility filters’ at the micro-evolutionary level driven by host/parasite ecology and physiology. Host specialization is hypothesized to result in trade-offs with aspects of parasite life history (e.g. reproductive output), but these have not been well studied. We used previously published data to create models examining general relationships among host specificity and important aspects of life history and reproduction for nematodes parasitizing animals. Our results indicate no general trade-off between host specificity and the average pre-patent period (time to first reproduction), female size, egg size, or fecundity of these nematodes. However, female size was positively related to egg size, fecundity, and pre-patent period. Host compatibility may thus not be the primary determinant of specificity in these parasitic nematodes if there are few apparent trade-offs with reproduction, but rather, the encounter opportunities for new host species at the micro-evolutionary level, and other processes at the macro-evolutionary level (i.e. phylogeny). Because host specificity is recognized as a key factor determining the spread of parasitic diseases understanding factors limiting host use are essential to predict future changes in parasite range and occurrence. [ABSTRACT FROM AUTHOR]

Objective. Unravelling the determinants of parasite life-history traits in natural settings is complex. Here, we deciphered the relationships between biotic, abiotic factors and the variation in 4 life-history traits (body size, egg presence, egg number and egg size) in the fish ectoparasite Tracheliastes polycolpus. We then determined the factors affecting the strength of the trade-off between egg number and egg size. Methods. To do so, we used 4-level (parasite, microhabitat, host and environment) hierarchical models coupled to a field database. Results. Variation in life-history traits was mostly due to individual characteristics measured at the parasite level. At the microhabitat level (fins of fish hosts), parasite number was positively related to body size, egg presence and egg number. Higher parasite number on fins was positively associated with individual parasite fitness. At the host level, host body size was positively related to the individual fitness of the parasite; parasites were bigger and more fecund on bigger hosts. In contrast, factors measured at the environmental level had a weak influence on life-history traits. Finally, a site-dependent trade-off between egg number and egg size existed in this population. Conclusion. Our study illustrates the importance of considering parasite life-history traits in a hierarchical framework to decipher complex links between biotic, abiotic factors and parasite life-history traits. [ABSTRACT FROM PUBLISHER]

Abstract: On the ecological timescale, two predator species with linear functional responses can stably coexist on two competing prey species. In this paper, with the methods of adaptive dynamics and critical function analysis, we investigate under what conditions such a coexistence is also evolutionarily stable, and whether the two predator species may evolve from a single ancestor via evolutionary branching. We assume that predator strategies differ in capture rates and a predator with a high capture rate for one prey has a low capture rate for the other and vice versa. First, by using the method of critical function analysis, we identify the general properties of trade-off functions that allow for evolutionary branching in the predator strategy. It is found that if the trade-off curve is weakly convex in the vicinity of the singular strategy and the interspecific prey competition is not strong, then this singular strategy is an evolutionary branching point, near which the resident and mutant predator populations can coexist and diverge in their strategies. Second, we find that after branching has occurred in the predator phenotype, if the trade-off curve is globally convex, the predator population will eventually branch into two extreme specialists, each completely specializing on a particular prey species. However, in the case of smoothed step function-like trade-off, an interior dimorphic singular coalition becomes possible, the predator population will eventually evolve into two generalist species, each feeding on both of the two prey species. The algebraical analysis reveals that an evolutionarily stable dimorphism will always be attractive and that no further branching is possible under this model. [Copyright &y& Elsevier]

Detailed knowledge of the effects of water on the migration of infective larvae of economically important trichostrongyloid species is urgently needed to feed into prediction models of future epidemiology. The influence of water on the migration of the parasitic nematodes Nematodirus battus, Haemonchus contortus and Teladorsagia circumcincta from sheep dung onto grass was examined in a series of laboratory experiments. Turf plots were seeded with larvae, which were recovered from grass clippings by serial sampling. Free water was necessary for larvae to escape from dung, but not for vertical migration onto grass. When temperature and relative humidity were held constant, the proportion of a population of live larvae present on herbage reached a plateau of around 2 (1–10)% after 24 h, and then changed little over time. Larvae in soil and dung formed a reservoir, such that a similar proportion of the larval population was maintained on grass after clipping. These findings suggest continuing random movement of free larvae. Implications for the epidemiology of trichostrongyloid species are discussed in the context of trade-offs faced by the parasites. [ABSTRACT FROM PUBLISHER]

Abstract: In many practical situations, we are not satisfied with the accuracy of the existing measurements. There are two possible ways to improve the measurement accuracy: [•] First, instead of a single measurement, we can make repeated measurements; the additional information coming from these additional measurements can improve the accuracy of the result of this series of measurements. [•] Second, we can replace the current measuring instrument with a more accurate one; correspondingly, we can use a more accurate (and more expensive) measurement procedure provided by a measuring lab – e.g., a procedure that includes the use of a higher quality reagent. In general, we can combine these two ways, and make repeated measurements with a more accurate measuring instrument. What is the appropriate trade-off between sample size and accuracy? This is the general problem that we address in this paper. [Copyright &y& Elsevier]

This paper presents economic analysis, viability and trade-off issues for small-scale (family) inland capture fisheries in three fishing communities, each representing a distinct floodplain characteristic in Cambodia. The average net profits of family fishing was US$12 and US$4.6 per trip during the open (October to May) and close (June to September) seasons, respectively; but real profit--deducting the cost for family labour from net profit--was only US$4.5 and US$1.6 during the open and close seasons, respectively. The return from family fishing varied greatly across sites surveyed, depending on the quality of the fishing grounds, hydro-ecology settings, local institutions, and socio-economic factors. The high degree of seasonality, the spatial variation of returns and costs of capture fisheries suggest interdependence of fishing activities with basin-level water allocation policies, and also related trade-off in the fisheries sector with water allocation and water resources management policies. There is also now an urgent need for synergy of the various rural development efforts with that of fisheries policies in the Mekong River Basin. [ABSTRACT FROM AUTHOR]

Abstract: In this study we use the theory of adaptive dynamics firstly to explore the differences in evolutionary behaviour of a generalist predator (or more specifically an omnivorous or intraguild predator) in a predator–prey model, with a Holling Type II functional response, when two distinct forms for the carrying capacity are used. The first of these involves the carrying capacity as an emergent property, whilst in the second it appears explicitly in the dynamics. The resultant effect this has on the intraspecific competition in each case is compared. Taking an identical trade-off in each case, we find that only with an emergent carrying capacity is evolutionary branching possible. Our study then concentrates solely on the case where the carrying capacity appears explicitly. Using the same model as above, but choosing alternate trade-offs, we find branching can occur with an explicit carrying capacity. Our investigation finishes by taking a more general functional response in an attempt to derive a condition for when branching can or cannot occur. For a predator–prey model, branching cannot occur if the functional response can be separated into two components, one a function of the population densities, X and Z, and the other a function of the evolving parameter z (traded off against the intrinsic growth rate), i.e. if F(z, X, Z)= F 1(z)F 2(X, Z). This search for evolutionary branching is motivated by its possible role in speciation. [Copyright &y& Elsevier]

The article reports on the debate on when and how brokers will shift funds. It contends that stock and bond returns have been nearly identical, regardless of the allocation between the two asset classes. Clinton Asset Management president Andrew Clinton says that there is a tendency to look at bonds as trades, not a placeholder for stability, noting that many have persuaded themselves that the stock market is not a fair playing field.