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1. Social trematode parasites increase standing army size in areas of greater invasion threat

   https://doi.org/10.1098/rsbl.2019.0765  

   Resetarits, Emlyn J. ; Torchin, Mark E. ; Hechinger, Ryan F. ( February 2020 , Biology Letters)

   Organisms or societies are resource limited, causing important trade-offs between reproduction and defence. Given such trade-offs, optimal allocation theory predicts that, for animal societies with a soldier caste, allocation to soldiers should reflect local external threats. Although both threat intensity and soldier allocation can vary widely in nature, we currently lack strong evidence that spatial variation in threat can drive the corresponding variation in soldier allocation. The diverse guild of trematode parasites of the California horn snail provides a useful system to address this problem. Several of these species form colonies in their hosts with a reproductive division of labourmore »including a soldier caste. Soldiers are non-reproductive and specialized in defence, attacking and killing invading parasites. We quantified invasion threat and soldier allocation for 168 trematode colonies belonging to six species at 26 sites spread among 10 estuaries in temperate and tropical regions. Spatial variation in invasion threat was matched as predicted by the relative number of soldiers for multiple parasite species. Soldier allocation correlated with invasion threat at fine spatial scales, suggesting that allocation is at least partly inducible. These results may represent the first clear documentation of a spatial correlation between allocation to any type of caste and a biotic selective agent.« less
2. Sources of variation in maternal allocation in a long‐lived mammal

   https://doi.org/10.1111/1365-2656.13243  

   Macdonald, Kaitlin R. ; Rotella, Jay J. ; Garrott, Robert A. ; Link, William A. ( October 2020 , Journal of Animal Ecology)

   1. Life history theory predicts allocation of energy to reproduction varies with maternal age, but additional maternal features may be important to the allocation of energy to reproduction. 2. We aimed to characterize age-specific variation in maternal allocation and assess the relationship between maternal allocation and other static and dynamic maternal features. 3. Mass measurements of 531 mothers and pups were used with Bayesian hierarchical models to explain the relationship between diverse maternal attributes and both the proportion of mass allocated by Weddell seal mothers, and the efficiency of mass transfer from mother to pup during lactation as well asmore »the weaning mass of pups. 4. Our results demonstrated that maternal mass was strongly and positively associated with the relative reserves allocated by a mother and a pup's weaning mass but that the efficiency of mass transfer declines with maternal parturition mass. Birthdate was positively associated with proportion mass allocation and pup weaning mass, but mass transfer efficiency was predicted to be highest at the mean birthdate. The relative allocation of maternal reserves declined with maternal age but the efficiency of mass transfer to pups increases, suggestive of selective disappearance of poor-quality mothers. 5. These findings highlight the importance of considering multiple maternal features when assessing variation in maternal allocation.« less
3. Effect of COVID-19 vaccine allocation strategies on vaccination refusal: a national survey

   https://doi.org/10.1080/13669877.2021.1936613  

   Bruine de Bruin, Wändi ; Ulqinaku, Aulona ; Goldman, Dana P. ( January 2021 , Journal of Risk Research)

   Wardman, Jamie (Ed.)

   Currently, one of the most pressing public health challenges is encouraging people to get vaccinated against COVID-19. Due to limited supplies, some people have had to wait for the COVID-19 vaccine. Consumer research has suggested that people who are overlooked in initial distribution of desired goods may no longer be interested. Here, we therefore examined people’s preferences for proposed vaccine allocation strategies, as well as their anticipated responses to being overlooked. After health-care workers, most participants preferred prioritizing vaccines for high-risk individuals living in group-settings (49%) or with families (29%). We also found evidence of reluctance if passed over. Aftermore »random assignment to vaccine allocation strategies that would initially overlook them, 37% of participants indicated that they would refuse the vaccine. The refusal rate rose to 42% when the vaccine allocation strategy prioritized people in areas with more COVID-19 – policies that were implemented in many areas. Even among participants who did not self-identify as vaccine hesitant, 22% said they would not want the vaccine in that case. Logistic regressions confirmed that vaccine refusal would be largest if vaccine allocation strategies targeted people who live in areas with more COVID-19 infections. In sum, once people are overlooked by vaccine allocation, they may no longer want to get vaccinated, even if they were not originally vaccine hesitant. Vaccine allocation strategies that prioritize high-infection areas and high-risk individuals in group-settings may enhance these concerns.« less
4. Improving Nash Social Welfare Approximations

   https://doi.org/10.24963/ijcai.2019/42  

   Garg, Jugal ; McGlaughlin, Peter ( August 2019 , Improving Nash Social Welfare Approximations)

   We consider the problem of fairly allocating a set of indivisible goods among n agents. Various fairness notions have been proposed within the rapidly growing field of fair division, but the Nash social welfare (NSW) serves as a focal point. In part, this follows from the 'unreasonable' fairness guarantees provided, in the sense that a max NSW allocation meets multiple other fairness metrics simultaneously, all while satisfying a standard economic concept of efficiency, Pareto optimality. However, existing approximation algorithms fail to satisfy all of the remarkable fairness guarantees offered by a max NSW allocation, instead targeting only the specific NSWmore »objective. We address this issue by presenting a 2 max NSW, Prop-1, 1/(2n) MMS, and Pareto optimal allocation in strongly polynomial time. Our techniques are based on a market interpretation of a fractional max NSW allocation. We present novel definitions of fairness concepts in terms of market prices, and design a new scheme to round a market equilibrium into an integral allocation that provides most of the fairness properties of an integral max NSW allocation. 

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5. Improving Nash Social Welfare Approximations

   https://doi.org/10.1613/jair.1.11618  

   McGlaughlin, Peter ; Garg, Jugal ( May 2020 , Journal of Artificial Intelligence Research)

   We consider the problem of fairly allocating a set of indivisible goods among n agents. Various fairness notions have been proposed within the rapidly growing field of fair division, but the Nash social welfare (NSW) serves as a focal point. In part, this follows from the ‘unreasonable’ fairness guarantees provided, in the sense that a max NSW allocation meets multiple other fairness metrics simultaneously, all while satisfying a standard economic concept of efficiency, Pareto optimality. However, existing approximation algorithms fail to satisfy all of the remarkable fairness guarantees offered by a max NSW allocation, instead targeting only the specific NSWmore »objective. We address this issue by presenting a 2 max NSW, Prop-1, 1/(2n) MMS, and Pareto optimal allocation in strongly polynomial time. Our techniques are based on a market interpretation of a fractional max NSW allocation. We present novel definitions of fairness concepts in terms of market prices, and design a new scheme to round a market equilibrium into an integral allocation in a way that provides most of the fairness properties of an integral max NSW allocation.« less