Periods Of Resource Scarcity Research Articles

Ethical boundary decisions in intensive care medicine

Ethical decision-making is acornerstone of intensive care and emergency medicine. In acute scenarios, clinicians often face rapid, high-stakes decisions concerning life and death, made more challenging by time constraints and incomplete information. These decisions are further complicated by economic constraints, limited resources, and evolving technological capabilities. What decision-making aids and factors can be employed in ethical borderline cases within intensive care medicine? Fundamental ethical principles such as patient autonomy, beneficence, non-maleficence, and justice form the basis for medical treatment decisions. Evaluating the patient's will through advanced directives or proxy consensus is crucial, although advanced directives can be ambiguous. Assessing quality of life is increasingly important, with instruments such as the Clinical Frailty Scale (CFS) being utilized. For older patients, aholistic approach is recommended, focusing on overall health rather than chronological age. In patients with advanced underlying diseases, amultidisciplinary dialogue is essential. Decision-making in intensive care medicine requires careful consideration of medical, ethical, and individual factors. Despite advances in artificial intelligence and prognostic models, human judgment remains crucial. During periods of resource scarcity, ethically sound triage protocols are required. The challenge lies in applying these principles and factors in clinical practice while respecting the individuality of each patient.

Resource gaps pose the greatest threat for bumblebees during the colony establishment phase

Abstract A common management intervention to support declining wild pollinators is ‘pollinator planting’. However, despite years of inclusion in conservation initiatives, global pollinator declines continue. Using the agent‐based model BEE‐STEWARD with two example species, Bombus terrestris (L. 1758) and B. pascuorum (Scopoli, 1763) (Hymenoptera: Apidae), we explore when during the year bumblebee resource demand is the highest and how that relates to seasonal changes in colony composition (numbers of eggs, larvae, pupae and adults). We then examine the impact of two‐week periods of resource scarcity across the year. Finally, we explore how enhancement with early spring‐blooming herbaceous species or trees changes colony survival and queen production. In the United Kingdom, there is a previously under‐appreciated ‘hungry gap’ for bumblebees in March–April, before the peak flight period, driven by the demands of larvae for protein and thermoregulation in the colony, rather than the number of adult bees. A 2‐week gap in forage availability during this period drives a 50%–87% drop in the production of daughter queens. Adding early‐blooming species in the model had significant, positive, long‐term effects on colony survival probability and daughter queen production. Pollinator‐planting initiatives in both national and international conservation schemes need to include plants that flower up to 1 month before the adults of target social pollinator species are apparent in the field, during the period that larvae dominate the colony. This approach is likely to increase colony survival and queen production, contributing towards halting and reversing global pollinator decline.

Which plant traits matter? Bromelia antiacantha Bertol. (Bromeliaceae) as a hibernation site for Brachystethus geniculatus (Fabricius) (Hemiptera, Pentatomidae, Edessinae)

ABSTRACT Diapause is a process of decreased metabolic activity in insects. In latitudes with a well-defined cold season, diapause or hibernation is a strategy to survive in periods of resource scarcity. In Pentatomidae, this phenomenon is studied mainly in non-natural environments and with species of economic importance. This work aimed to determine which variables influence the abundance of Brachystethus geniculatus on its hibernation site, Bromelia antiacantha. Samplings were carried out monthly, from July to September of 2019, in a remnant of Atlantic Forest in southern Brazil. The height, diameter, cup height, leaf width, and abundance of bromeliads per plant cluster were evaluated for their correlation with the abundance of B. geniculatus in bromeliads. We collected 24 individuals for analysis of fat bodies, in order to check diapause. We found 70 individuals of B. geniculatus distributed in 33 of the 61 bromeliads examined. The number of B. geniculatus per bromeliad was positively correlated with the cup height, that influences the opening of the leaves and consequently decreases the exposure to environmental weathering, and the number of bromeliads per group, possibly because more leaves and spines around the cup may help avoid predation. Parasitism on B. geniculatus by tachinid flies was recorded in the field.

Shifts in risk sensitivity and resource availability alter fat stores for a large mammal following extreme winter conditions

Abstract For species that inhabit environments where resource availability may be unpredictable, balance of resource allocation to life‐history traits can have heightened consequences for survival, reproduction, and ultimately, fitness. Acquisition and allocation of energy to maintenance, capital gain and reproduction should be in tune with the landscape an animal inhabits—environmental severity, food availability and population size all influence the resources animals have and dictate the ways they should be allocated. In seasonal environments, animals that experience periods of extreme resource limitation (e.g. harsh winters) may favour allocation of resources to body reserves to secure their survival at the cost of reproduction (i.e. risk averse). In contrast, the same accumulation of body reserves may not be necessary to survive in relatively benign landscapes where instead, allocation to reproduction is favoured (i.e. risk prone). According to the theory of risk‐sensitive allocation of resources, when animals are exposed to unprecedented or life‐threatening conditions, they may shift resource allocation to favour building capital over allocation in reproduction to preempt against encountering another life‐threatening event in the future. Using data from a long‐term project on a highly site‐faithful and long‐lived species, mule deer (Odocoileus hemionus), we evaluated how a life‐threatening winter and the associated changes in resource availability resulting from a population reduction influenced how animals acquired and allocated energy to survival (i.e. fat accumulation). Per capita precipitation, and the associated reduction in population abundance after the severe winter, had a positive influence of accrual of fat over summer. After the extreme physiological stress of a hard winter, deer starting spring with low body reserves accumulated 2.8 percentage points more fat over summer compared with before the experience of a bad winter and had an increased probability of recruiting fewer offspring. Fat stores can interact with environment, life history and behaviour to influence survival during periods of resource scarcity. For a long‐lived herbivore, we documented shifts in risk tolerance associated with fat accrual in preparation for winter, supporting the notion that risk‐sensitive allocation of resources may be plastic—an essential adaptation for animals to cope with rapidly changing landscapes. Read the free Plain Language Summary for this article on the Journal blog.

Mean age at menarche and climate variables on a global scale.

Cross-population variation in age at menarche is related to many factors. The purpose of this study was to examine climate variables in relation to mean age at menarche among 87 modern human populations. We hypothesized a later age at menarche among populations living in areas with high precipitation variability, heavy seasonal rainfall, and high temperatures year-round due to water-borne diseases and periods of resource scarcity. Using a comparative dataset, we examined geospatial distribution and climate variables in relation to age at menarche for 87 modern human populations. We found the strongest predictor of a later age at menarche was higher fertility followed by a later mean age at death. In addition, higher annual rainfall, higher precipitation seasonality, and lower annual mean temperature were moderate predictors of age at menarche. We propose that later ages at menarche in countries with high fertility may be a life-history strategy developed in response to climatic conditions that have resulted in higher immunological load. In these conditions, females may prioritize growth rather than reproduction. Shifts in climate and global population growth may change the future biological landscape of age at menarche.

Clinical Prioritization of Antispike Monoclonal Antibody Treatment of Mild to Moderate COVID-19

Clinical Prioritization of Antispike Monoclonal Antibody Treatment of Mild to Moderate COVID-19

Different approach to medical decision-making in difficult circumstances: Kittay’s Ethics of Care

The onset of the COVID-19 pandemic has necessitated advances in bioethical approaches to medical decision-making. This paper develops an alternative method for rationing care during periods of resource scarcity. Typical...

How Should ECMO Be Used Under Conditions of Severe Scarcity? A Population Study of Public Perception

ObjectiveTo assess societal preferences regarding allocation of extracorporeal membrane oxygenation (ECMO) as a rescue option for select patients with coronavirus disease 2019 (COVID-19).DesignCross-sectional survey of a nationally representative sample.SettingAmazon Mechanical Turk platform.ParticipantsIn total, responses from 1,041 members of Amazon Mechanical Turk crowd-sourcing platform were included. Participants were 37.9 ± 12.6 years old, generally white (65%), and college-educated (66.1%). Many reported working in a healthcare setting (22.5%) and having a friend or family member who was admitted to the hospital (43.8%) or died from COVID-19 (29.9%).Measurements and Main ResultsAlthough most reported an unwillingness to stay on ECMO for >one week without signs of recovery, participants were highly supportive of ECMO utilization as a life-preserving technique on a policy level. The majority (96.7%) advocated for continued use of ECMO to treat COVID patients during periods of resource scarcity but would prioritize those with highest likelihood of recovery (50%) followed by those who were sickest regardless of survival chances (31.7%). Patients >40 years old were more likely to prefer distributing ECMO on a first-come first-served basis (21.5% v 13.3%, p < 0.05).ConclusionEven though participants expressed hesitation regarding ECMO in personal circumstances, they were uniformly in support of using ECMO to treat COVID patients at a policy level for others who might need it, even in the setting of severe scarcity.

Frugivory and seed dispersal in a hyperdiverse plant clade and its role as a keystone resource for the Neotropical fauna.

Much of our understanding of the ecology and evolution of seed dispersal in the Neotropics is founded on studies involving the animal-dispersed, hyperdiverse plant clade Miconia (Melastomataceae). Nonetheless, no formal attempt has been made to establish its relevance as a model system or indeed provide evidence of the role of frugivores as Miconia seed dispersers. We built three Miconia databases (fruit phenology/diaspore traits, fruit-frugivore interactions and effects on seed germination after gut passage) to determine how Miconia fruiting phenology and fruit traits for >350 species interact with and shape patterns of frugivore selection. In addition, we conducted a meta-analysis evaluating the effects of animal gut passage/seed handling on Miconia germination. Miconia produce numerous small berries that enclose numerous tiny seeds within water- and sugar-rich pulps. In addition, coexisting species provide sequential, year long availability of fruits within communities, with many species producing fruits in periods of resource scarcity. From 2396 pairwise interactions, we identified 646 animal frugivore species in five classes, 22 orders and 60 families, including birds, mammals, reptiles, fish and ants that consume Miconia fruits. Endozoochory is the main dispersal mechanism, but gut passage effects on germination were specific to animal clades; birds, monkeys and ants reduced seed germination percentages, while opossums increased it. The sequential fruiting phenologies and wide taxonomic and functional diversity of animal vectors associated with Miconia fruits underscore the likely keystone role that this plant clade plays in the Neotropics. By producing fruits morphologically and chemically accessible to a variety of animals, Miconia species ensure short- and long-distance seed dispersal and constitute reliable resources that sustain entire frugivore assemblages.

Chimpanzee ranging responses to fruit availability in a high-elevation environment.

Most primates experience seasonal fluctuations in the availability of food resources and face the challenge of balancing energy expenditure with energy gain during periods of resource scarcity. This is likely to be particularly challenging in rugged, montane environments, where available energy is relatively low and travel costs are high. Chimpanzees (Pan troglodytes) show extensive behavioral diversity across study sites. Yet, as most research has focused on low- and mid-elevation sites, little is known on how chimpanzees respond to periods of low fruit availability in harsh montane environments. We use focal follow and phenology data to investigate how fruit availability influences daily path length and monthly home range in chimpanzees living in Nyungwe National Park, a montane forest in Rwanda. Nyungwe chimpanzees decreased their daily travel distances during periods of fruit scarcity. However, this decrease in travel effort did not correspond with a decrease in foraging area. Instead, monthly homes ranges shifted location across the study period. Nyungwe chimpanzees occupy a relatively wide altitudinal range and the shifts in monthly home range location may reflect differences in the altitudinal distribution of food resources. Chimpanzee monthly diet was often dominated by one or two species and each of these species were confined to different elevation zones. One important species, Podocarpus latifolius, grew only at high elevations (2,600-2,950 m) and chimpanzees ranged at the altitudinal peak of their range for 2 consecutive months while feeding on this species. Thus, while high elevations are often thought to be harsh environments for primates, they can be an important part of a species' home range when they provide a refugium for densely distributed, important food species.

Diet and Use of Fallback Foods by Rwenzori Black-and-White Colobus (Colobus angolensis ruwenzorii) in Rwanda: Implications for Supergroup Formation

When preferred foods are scarce, one strategy employed by primates is to switch to an alternative food item of lower quality or preferability, i.e., a fallback food. In the montane rainforest of Nyungwe National Park in southwestern Rwanda, Rwenzori black-and-white colobus (Colobus angolensis ruwenzorii) (hereafter Rwenzori colobus) form a supergroup comprising hundreds of individuals. Over 13 mo we investigated how this supergroup uses resources in periods of resource abundance vs. periods of resource scarcity. Based on 5603 feeding records we first identified preferred foods and then identified fallback foods as those food categories or species whose consumption increases when preferred foods, or preferred food categories, are less available. When the availability of 19 preferred food items was low, fruticose lichens (Usnea sp.) contributed >50% of the monthly diet for the Rwenzori colobus. Moreover, consumption of lichens was significantly negatively related to the availability of preferred foods. Fruticose lichens can therefore be considered a fallback food for Rwenzori colobus that sustains the supergroup during periods of reduced food availability. This result, in combination with previous findings that mature foliage in Nyungwe is of high quality and does not elicit feeding competition, points to the importance of resources in facilitating supergroup formation. However, several other montane forests in Eastern Africa also harbor fruticose lichens and yet support only small groups of Angolan colobus, suggesting that additional factors such as sufficient forest size and limited fragmentation and hunting pressure by humans are required for supergroups to form.

Recycling and metabolic flexibility dictate life in the lower oceanic crust.

The lithified lower oceanic crust is one of Earth's last biological frontiers as it is difficult to access. It is challenging for microbiota that live in marine subsurface sediments or igneous basement to obtain sufficient carbon resources and energy to support growth1-3 or to meet basal power requirements4 during periods of resource scarcity. Here we show how limited and unpredictable sources of carbon and energy dictate survival strategies used by low-biomass microbial communities that live 10-750m below the seafloor at Atlantis Bank, Indian Ocean, where Earth's lower crust is exposed at the seafloor. Assays of enzyme activities, lipid biomarkers, marker genes and microscopy indicate heterogeneously distributed and viable biomass with ultralow cell densities (fewer than 2,000 cells per cm3). Expression of genes involved in unexpected heterotrophic processes includes those with a role inthe degradation of polyaromatic hydrocarbons, use of polyhydroxyalkanoates as carbon-storage molecules and recycling of amino acids to produce compounds that can participate in redox reactions and energy production. Our study provides insights into how microorganisms in the plutonic crust are able to survive within fractures or porous substrates by coupling sources of energy to organic and inorganic carbon resources that are probably delivered through the circulation of subseafloor fluids or seawater.

On the interplay between hypothermia and reproduction in a high arctic ungulate

For free-ranging animals living in seasonal environments, hypometabolism (lowered metabolic rate) and hypothermia (lowered body temperature) can be effective physiological strategies to conserve energy when forage resources are low. To what extent such strategies are adopted by large mammals living under extreme conditions, as those encountered in the high Arctic, is largely unknown, especially for species where the gestation period overlaps with the period of lowest resource availability (i.e. winter). Here we investigated for the first time the level to which high arctic muskoxen (Ovibos moschatus) adopt hypothermia and tested the hypothesis that individual plasticity in the use of hypothermia depends on reproductive status. We measured core body temperature over most of the gestation period in both free-ranging muskox females in Greenland and captive female muskoxen in Alaska. We found divergent overwintering strategies according to reproductive status, where pregnant females maintained stable body temperatures during winter, while non-pregnant females exhibited a temporary decrease in their winter body temperature. These results show that muskox females use hypothermia during periods of resource scarcity, but also that the use of this strategy may be limited to non-reproducing females. Our findings suggest a trade-off between metabolically-driven energy conservation during winter and sustaining foetal growth, which may also apply to other large herbivores living in highly seasonal environments elsewhere.

Some Initial Observations Concerning the African Wild Banana Ensete ventricosum as a Resource for Vertebrates

The ecological role and significance of “African wild bananas” Ensete ventricosum (Welw.) Cheesman (Musaceae) are unknown. We considered if E. ventricosum, with its sustained flowering and fruiting, might act in some ways like a keystone species by supporting animal populations during periods of resource scarcity. We deployed camera traps facing flowers or fruits of E. ventricosum for a total of 40 camera months in the Bwindi Impenetrable National Park, Uganda. We recorded 1,691 visitor events by 11 vertebrate species to flowers and fruits (1,129 events by five species to flowers and 562 events by eight species to fruits); these visitors included potential pollinators and seed dispersers. Frequent visitors to flowers were the African dormouse Graphiurus murinus (53.3%), Nectar bat Megaloglossus woermanni (43.8%), and sunbirds (family Nectariniidae) (2.4%) while those to fruits were Carruther’s mountain squirrel Funisciurus carruthersi (54.1%), L'hoest's monkey Allochrocebus l’hoesti (18.7%), and Forest giant pouched rat Cricetomys emini (18.6%). Flower visitors were mainly nocturnal (with birds favoring dusk), while fruit visitors exhibited both diurnal and nocturnal activity patterns. The data indicate that by producing flowers and fruits continuously, E. ventricosum should support animal populations when other flower and fruit resources are scarce. We speculate that establishing these plants in degraded areas may facilitate forest resilience and recovery while providing fallback resources to many species. Such plant species are prime contenders for protection and restoration.

Periodic resource scarcity and potential for interspecific competition influences distribution of small carnivores in a seasonally dry tropical forest fragment

Small, isolated, and disturbed forest fragments potentially offer valuable habitats for small carnivore conservation. Yet the influence of resource availability—critical for survival and reproduction—on small carnivore habitat use within these modified environments is poorly understood. We conducted camera-trap surveys within a seasonally dry tropical forest fragment (148 km2) in northeastern Thailand to better understand the influence resource availability has on small carnivore habitat use within fragmented areas. Species occupancy models including both habitat and resource variables were assessed across periods of high and low resource availability (fruit abundance and rodent biomass). Species with similar resource or habitat preferences may also compete when resources are low. Therefore, we tested species with shared preferences for patterns of spatial co-occurrence and temporal overlap. Fruit availability influenced the distribution of common palm civet (Paradoxurus hermaphroditus), while rodent biomass influenced Asiatic jackal (Canis aureus), leopard cat (Prionailurus bengalensis), and small Indian civet (Viverricula indica), but only during annual periods of scarcity. In contrast, small Asian mongoose (Herpestes javanicus) was highly selective for a specific habitat (dry dipterocarp forest) regardless of seasonal fluctuations in food availability. Occupancy increased for all species during periods of resource scarcity, with leopard cat and Asiatic jackal experiencing the greatest increases (139% and 58%, respectively). Species with shared resource and habitat preferences appeared to avoid each other, either spatially or temporally. For example, leopard cat and Asiatic jackal co-occurred spatially less than would be expected, though only when rodents were scarce. Similarly, small Indian civet and small Asian mongoose, which used the same habitat and co-occurred spatially at a rate greater than expected, were active at different times. Our results indicate that seasonal resource fluctuations and interspecific interactions strongly influence the distribution of sympatric small carnivores in a fragmented forest.

Natural selection in bats with historical exposure to white-nose syndrome

BackgroundHibernation allows animals to survive periods of resource scarcity by reducing their energy expenditure through decreased metabolism. However, hibernators become susceptible to psychrophilic pathogens if they cannot mount an efficient immune response to infection. While Nearctic bats infected with white-nose syndrome (WNS) suffer high mortality, related Palearctic taxa are better able to survive the disease than their Nearctic counterparts. We hypothesised that WNS exerted historical selective pressure in Palearctic bats, resulting in genomic changes that promote infection tolerance.ResultsWe investigated partial sequences of 23 genes related to water metabolism and skin structure function in nine Palearctic and Nearctic hibernating bat species and one non-hibernating species for phylogenetic signals of natural selection. Using maximum likelihood analysis, we found that eight genes were under positive selection and we successfully identified amino acid sites under selection in five encoded proteins. Branch site models revealed positive selection in three genes. Hibernating bats exhibit signals for positive selection in genes ensuring tissue regeneration, wound healing and modulation of the immune response.ConclusionOur results highlight the importance of skin barrier integrity and healing capacity in hibernating bats. The protective role of skin integrity against both pathophysiology and WNS progression, in synergy with down-regulation of the immune reaction in response to the Pseudogymnoascus destructans infection, improves host survival. Our data also suggest that hibernating bat species have evolved into tolerant hosts by reducing the negative impact of skin infection through a set of adaptations, including those at the genomic level.

Stingless bees (Melipona subnitida) adjust brood production rather than foraging activity in response to changes in pollen stores.

Highly eusocial bees (honey bees and stingless bees) sustain their colonies through periods of resource scarcity by food stored within the nest. The protein supply necessary for successful brood production is ensured through adjustments of the colonies' pollen foraging according to the availability of this resource in the environment. In honey bees Apis mellifera, in addition, pollen foraging is regulated through the broods' demand for this resource. Here, we investigated the influence of the colony's pollen store level on pollen foraging and brood production in stingless bees (Melipona subnitida). When pollen was added to the nests, colonies increased their brood production and reduced their pollen foraging within 24h. On the other hand, when pollen reserves were removed, colonies significantly reduced their brood production. In strong contrast to A. mellifera; however, M. subnitida did not significantly increase its pollen foraging activity under poor pollen store conditions. This difference concerning the regulation of pollen foraging may be due to differences regarding the mechanism of brood provisioning. Honey bees progressively feed young larvae and, consequently, require a constant pollen supply. Stingless bees, by contrast, mass-provision their brood cells and temporary absence of pollen storage will not immediately result in substantial brood loss.

Rainbow trout in seasonal environments: phenotypic trade-offs across a gradient in winter duration.

Survival through periods of resource scarcity depends on the balance between metabolic demands and energy storage. The opposing effects of predation and starvation mortality are predicted to result in trade-offs between traits that optimize fitness during periods of resource plenty (e.g., during the growing season) and those that optimize fitness during periods of resource scarcity (e.g., during the winter). We conducted a common environment experiment with two genetically distinct strains of rainbow trout to investigate trade-offs due to (1) the balance of growth and predation risk related to foraging rate during the growing season and (2) the allocation of energy to body size prior to the winter. Fry (age 0) from both strains were stocked into replicate natural lakes at low and high elevation that differed in winter duration (i.e., ice cover) by 59 days. Overwinter survival was lowest in the high-elevation lakes for both strains. Activity rate and growth rate were highest at high elevation, but growing season survival did not differ between strains or between environments. Hence, we did not observe a trade-off between growth and predation risk related to foraging rate. Growth rate also differed significantly between the strains across both environments, which suggests that growth rate is involved in local adaptation. There was not, however, a difference between strains or between environments in energy storage. Hence, we did not observe a trade-off between growth and storage. Our findings suggest that intrinsic metabolic rate, which affects a trade-off between growth rate and overwinter survival, may influence local adaptation in organisms that experience particularly harsh winter conditions (e.g., extended periods trapped beneath the ice in high-elevation lakes) in some parts of their range.

Changes to Metabolism and Cell Physiology that Enable Mammalian Hibernation

Heterothermy is a widespread, adaptive strategy used by many species of bird and mammal to conserve energy during periods of energetic deficit, the expression of which varies greatly depending on the species and environment. A temporary, reversible reduction in metabolic rate and body temperature (i.e., torpor) is an adaptive response used by many species of birds and mammals to conserve energy during periods of resource scarcity. Long-term employment of torpor (i.e., hibernation) is a seasonally expressed phenotype, the genetic and regulated pathways of which can be found throughout all mammal lineages, including hibernators and nonhibernators alike. In mammals, adaptations that allow for hibernation can be classified as those involved in preparation for hibernation, metabolic reduction, continued cellular function and protection, and arousal. Key physiological changes involve seasonal regulation of metabolic hormones, a shift to largely using endogenous fuel sources (i.e., increased lipolysis), global down regulation of protein transcription by posttranslational modification and microRNA save for the increased production of a small number of protective proteins, shifts in membrane composition, and thermogenesis by brown adipose tissue. There is some evidence of cold acclimations in nonhibernators, such as during fetal development, but responses are limited and cursory, and eventually cellular damage occurs. Therefore, it appears that a complete suite of adaptations to metabolism, vital physiological functions, and thermogenic mechanisms is required for the successful expression of the hibernation phenotype.

Studying the Relationship between System-Level and Component-Level Resilience

The capacity to maintain stability in a system relies on the components which make up the system. This study explores the relationship between component-level resilience and system-level resilience with the aim of identifying policies which foster system-level resilience in situations where existing incentives might undermine it. We use an abstract model of interacting specialized resource users and producers which can be parameterized to represent specific real systems. We want to understand how features, such as stockpiles, influence system versus component resilience. Systems are subject to perturbations of varying intensity and frequency. For our study, we create a simplified economy in which an inventory carrying cost is imposed to incentivize smaller inventories and examine how components with varying inventory levels compete in environments subject to periods of resource scarcity. The results show that policies requiring larger inventories foster higher component-level resilience but do not foster higher system-level resilience. Inventory carrying costs reduce production efficiency as inventory sizes increase. JIT inventory strategies improve production efficiency but do not afford any buffer against future uncertainty of resource availability.