Resource Trade-offs Research Articles

“Born with a silver spoon in the mouth has bad sides too”: Experimentally increasing growth rate enhances individual quality but accelerates reproductive senescence in females of the mealworm beetle, Tenebrio molitor

Senescence occurs because of the decline of the strength of selection with age, allowing late-life reduced performances not being counter selected. From there, several phenomena may explain late-life reduced performances, such as the accumulation of deleterious mutations, the expression of pleiotropic genes or the existence of resource trade-offs between early and late performances. This latter phenomenon is at the core of the disposable soma theory of aging, which predicts that growth and early-life reproduction have costs that increase reproductive and actuarial senescence. Whereas the impact of the cost of early reproduction on reproductive and actuarial senescence has been extensively studied, that of the cost of growth remains overlooked and often inconclusive, possibly because of confounding effects associated with the procedures used to manipulate growth rate. Here, we investigated the cost of growth rate and its impact on reproductive senescence and longevity of females of the mealworm beetle, Tenebrio molitor. For this purpose, we generated insects with contrasted growth rates by raising groups of them in conditions below, above and optimal relative humidity (RH: 55, 85 and 70%, respectively) during the larval stage. The resulting adult females then bred, under the same optimal RH conditions, early in life, then later in life and were followed there until death. We found that larvae grown under the highest relative humidity exhibited the highest larval growth rate, thanks to both shorter growth duration and the achievement of heavier pupae mass. Adult females from this favorable growing condition lived longer, were more fecund early in life, but suffered from lower late-life reproductive investment. Our study shows that growth rate, which is highly dependent on the early-life environment, is an important factor modulating adult reproductive senescence, through the occurrence of early-late life trade-offs.

Two sparsities are better than one: unlocking the performance benefits of sparse–sparse networks

In principle, sparse neural networks should be significantly more efficient than traditional dense networks. Neurons in the brain exhibit two types of sparsity; they are sparsely interconnected and sparsely active. These two types of sparsity, called weight sparsity and activation sparsity, when combined, offer the potential to reduce the computational cost of neural networks by two orders of magnitude. Despite this potential, today’s neural networks deliver only modest performance benefits using just weight sparsity, because traditional computing hardware cannot efficiently process sparse networks. In this article we introduce Complementary Sparsity, a novel technique that significantly improves the performance of dual sparse networks on existing hardware. We demonstrate that we can achieve high performance running weight-sparse networks, and we can multiply those speedups by incorporating activation sparsity. Using Complementary Sparsity, we show up to 100× improvement in throughput and energy efficiency performing inference on FPGAs. We analyze scalability and resource tradeoffs for a variety of kernels typical of commercial convolutional networks such as ResNet-50 and MobileNetV2. Our results with Complementary Sparsity suggest that weight plus activation sparsity can be a potent combination for efficiently scaling future AI models.

Changes of leaf functional traits of Pinus tabuliformis in burned areas with different fire severities

The response of leaf functional traits to forest fire is one of the research hotspots in the forest fire ecology. Studying post-fire changes in leaf functional traits of Pinus tabuliformis can reveal its growth strategies to adapt to fire environment and provide reference for the post-fire recovery. We analyzed the changes of leaf functional traits in burned areas with different fire severities (unburned, light burn and moderate burn) in Qinyuan County burned area of Shanxi Province, and studied the variation characteristics of leaf economic spectrum in different burned areas. The results showed that there were significant differences in burned areas with different fire severities for all leaf functional traits except N/P. Among them, the difference of leaf area was the most obvious, which was the most sensitive trait. With the increases of fire severity in burned areas, leaf area, leaf thickness, leaf dry matter content, leaf nitrogen content and leaf phosphorus content increased, while specific leaf area and leaf organic carbon content decreased. There were significant correlations among some leaf functional traits, with the correlations being distinct in burned areas with different fire severities. The leaf economic spectrum moved from 'unburned-light burn-mode-rate burn' to the resource trade-off strategy of 'rapid investment-return type' along the fire environment. The recovery of P. tabuliformis would be accelerated in burned area with low fire severity.

An Integrated Approach to Peace and Resource Security

This paper explores the value proposition of using systems tools to model the interlinkages that exist between the security of water, energy, land, and food (WELF) resources and peace. The intersection between these five sectors, referred to as the WELF-Peace nexus, is complex, unfolds in a constrained landscape of specific context and scale, and involves the interaction of multiple systems and their subsystems. Multiple states of combined community peace and resource security are possible. This paper demonstrates the value proposition of using system dynamics to account for the interdependencies that exist between the four sectors of the WELF nexus and the domains of positive peace. Two existing indices, the Positive Peace Index and the Pardee RAND Food-Energy-Water (FEW) Security Index proposed by the Institute for Economy and Peace (IEP) are considered, and their interaction analyzed using system dynamics. The approach can be used to explore different scenarios involving linkages between positive peace and different forms of FEW resource synergy and tradeoff.

Variation and determinants of leaf anatomical traits from boreal to tropical forests in eastern China

Leaf anatomical traits are responsive to environmental factors and thus highly plastic in their development and biochemical function. However, how they vary across large geographical scales and the main driving factors remain unclear, especially for forest plants. Here, by combining field sampling with plant semi-thin sectioning methods, eight anatomical traits (including leaf epidermis and mesophyll traits, leaf midrib and vascular traits) that can fully reflect leaf structure were measured in 60 plant species inhabiting eight forests in eastern China, and their geographical patterns and possible determinants were explored. Our results showed that leaf anatomical traits varied significantly among different plant functional types (PFTs), and phylogeny had a negligible effect on them. At the species level, leaf anatomical traits exhibited significant geographical patterns, and the thickness of leaf tissues tended to increase from boreal to tropical forests. Compared to leaf epidermis and mesophyll traits, leaf midrib and vascular traits showed similar and more significant geographical patterns. Moreover, the spatial variations in leaf anatomical traits were mainly determined by the shifts in PFTs, while climate and soil nutrient availability had relatively marginal effects. Our findings emphasized that leaf anatomical trait coordination could reflect the resource trade-off and utilization strategies of plants, which is expected to improve our understanding of the responses and adaptation mechanisms of plants to environmental changes.

Revealing energy and water hidden in Chinese regional critical carbon supply chains

In the context of “carbon peaking” and “carbon neutrality” and significant differences in regional industrial structure of China, this study identified energy and water resources embodied in the top 15 CO2 supply chains of each province in 2017 using the environmentally extended multiregional input–output and structural path analysis method. It also explored the impact of reducing CO2 along these critical supply chains on regional energy and water resources. The study showed that the critical CO2 supply chains in 30 provinces embodied 1859.2 Mt CO2 emissions, accounting for 24% of the total national final consumption. Meanwhile, these supply chains also embodied 354.9 Mt energy and 25033 Mt water resource, accounting for 17% and 5% of total national consumption, respectively. A tradeoff of energy and water resources existed in the low-carbon transition in upstream sectors, while the downstream sector had a great carbon–energy–water synergy potential. The shift of fixed capital investment from conventional construction to new infrastructure with less consumption of both energy and water was conducive to the sustainable development of resources and the environment. Thus, this study provided some suggestions for a low-carbon transition promoting the sustainable management of energy and water resources in all regions.

U.S. national water and energy land dataset for integrated multisector dynamics research

Understanding resource demands and tradeoffs among energy, water, and land socioeconomic sectors requires an explicit consideration of spatial scale. However, incorporation of land dynamics within the energy-water nexus has been limited due inconsistent spatial units of observation from disparate data sources. Herein we describe the development of a National Water and Energy Land Dataset (NWELD) for the conterminous United States. NWELD is a 30-m, 86-layer rasterized dataset depicting the land use of mappable components of the United States energy sector life cycles (and related water used for energy), specifically the extraction, development, production, storage, distribution, and operation of eight renewable and non-renewable technologies. Through geospatial processing and programming, the final products were assembled using four different methodologies, each depending upon the nature and availability of raw data sources. For validation, NWELD provided a relatively accurate portrayal of the spatial extent of energy life cycles yet displayed low measures of association with mainstream land cover and land use datasets, indicating the provision of new land use information for the energy-water nexus.

Microbial nutrient limitation and catalytic adjustments revealed from a long‐term nutrient restriction experiment

AbstractIntroductionMicrobial abundance and activities in soils are predominantly determined by soil carbon (C), nitrogen (N) and phosphorus (P) availability. Much research has focused on the effects of soil N than P availability on soil microbial biomass and enzyme activities as sensitive proxies of microbial ecophysiology highlighting the need to investigate how microbes will respond to P availability in soil, especially in cropping systems.Materials and MethodsThe effect of P fertilisation on microbial biomass‐C, ‐N and ‐P, and the kinetic parameters (maximal velocity [Vmax], Michaelis constant [Km] and catalytic efficiency [Ka]) of β‐1,4‐glucosidase (BG; C‐acquiring), leucine‐aminopeptidase (LAP; predominantly N‐acquiring) and acid phosphomonoesterase (PHO; P‐acquiring) were measured in a nutrient‐poor agricultural soil (devoid of fertiliser application since 1942).ResultsThis study showed that P fertilisation led to a 65% and 56% increase in microbial biomass‐N and ‐P, respectively, indicating severe P limitation and inefficient N acquisition by microbes without P availability. Increased Ka values of LAP with P fertilisation further hint toward the production of efficient isoenzymes to avoid resource tradeoffs for nutrient acquisition.ConclusionsOverall, these results decipher microbial metabolic and catalytic adjustments mediated by soil P availability. Increased microbial biomass‐N and ‐P with P fertilisation indicated microbial N and P colimitation that was partly overcome by the production of efficient enzymes for N acquisition with P fertilisation. We argue to incorporate microbial enzyme activities as a response to different management strategies to better inform us about soil biogeochemical cycles in cropping systems.

Topology-Abstraction-Based Protection Scheme in Quantum Key Distribution Networks with Partially Trusted Relays

Quantum key distribution (QKD) can protect the exchange process of confidential information between communicating parties. By using the basic principles of quantum mechanics and combined with “one-time pad” cipher encryption, information can be unconditionally secure. The BB84 protocol first describes the method of transmitting information by photon polarization state, and it expounds the transmission process of services between trusted relays. However, due to the defects of real experimental devices, there are security vulnerabilities in QKD in a real system. The birth of measurement-device-independent quantum key distribution (MDI-QKD) protocol solves the problem, providing immunity to hacker attacks at the end of the detector. It can enable both sides of the transmission service to establish a connection and generate secret keys through an untrusted relay node to ensure information security. However, the types and properties of link nodes in quantum key distribution network (QKDN) based on partially trusted relay are more complex, which can easily result in network fault. Therefore, how to prevent the impact of failure on QKDN has become an urgent problem. In this paper, we propose a protection scheme for QKDN with partially trusted relays. The method deals with trusted and untrusted relays differently and constructs the working and protection paths of the secret key for each service. It reduces resource conflict between the protection and working paths by establishing a key protection threshold, which realizes the resource trade-off between the two factors. Simulation results show that the scheme provides effective protection to the services, and it improves the stability and reliability of QKDN based on partially trusted relay.

How High to Fly? Mapping Evapotranspiration from Remotely Piloted Aircrafts at Different Elevations

Recent advancements in remotely piloted aircrafts (RPAs) have made frequent, low-flying imagery collection more economical and feasible than ever before. The goal of this work was to create, compare, and quantify uncertainty associated with evapotranspiration (ET) maps generated from different conditions and image capture elevations. We collected optical and thermal data from a commercially irrigated potato (Solanum tuberosum) field in the Wisconsin Central Sands using a quadcopter RPA system and combined multispectral/thermal camera. We conducted eight mission sets (24 total missions) during the 2019 growing season. Each mission set included flights at 90, 60, and 30 m above ground level. Ground reference measurements of surface temperature and soil moisture were collected throughout the domain within 15 min of each RPA mission set. Evapotranspiration values were modeled from the flight data using the High-Resolution Mapping of Evapotranspiration (HRMET) model. We compared HRMET-derived ET estimates to an Eddy Covariance system within the flight domain. Additionally, we assessed uncertainty for each flight using a Monte Carlo approach. Results indicate that the primary source of uncertainty in ET estimates was the optical and thermal data. Despite some additional detectable features at low elevation, we conclude that the tradeoff in resources and computation does not currently justify low elevation flights for annual vegetable crop management in the Midwest USA.

Time for Physical Activity: Different, Unequal, Gendered.

We investigate time inequity as an explanatory mechanism for gendered physical activity disparity. Our mixed-effect generalized linear model with two-stage residual inclusion framework uses longitudinal data, capturing differing exchanges and trade-offs in time resources. The first stage estimates within-household exchanges of paid and family work hours. Estimates show that men's employment increases women's family work hours while reducing their own, whereas women's employment weakly affects men's family time. Incorporating unequal household exchange into the second stage reveals that as women's paid or family work hours increase, physical activity goes down. In contrast, men's physical activity is unaffected by paid work hours, and family time appears protective. Control over work time further underscores gendered time exchange: Men's activity increases with own or partner's control, whereas women's increases only with their own. Our approach reveals how men's and women's unequal capability to use time creates differing trade-offs between work, family, and physical activity, generating health inequity.

Impacts of the choice of distance measurement method on estimates of access to point-based resources.

Lack of access to resources such as medical facilities and grocery stores is related to poor health outcomes and inequities, particularly in an environmental justice framework. There can be substantial differences in quantifying "access" to such resources, depending on the geospatial method used to generate distance estimates. We compared three methods for calculating distance to the nearest grocery store to illustrate differential access at the census block-group level in the Atlanta metropolitan area, including: Euclidean distance estimation, service areas incorporating roadways and other factors, and cost distance for every point on the map. We found notable differences in access across the three estimation techniques, implying a high potential for exposure misclassification by estimation method. There was a lack of nuanced exposure in the highest- and lowest-access areas using the Euclidean distance method. We found an Intraclass Correlation Coefficient (ICC) of 0.69 (0.65, 0.73), indicating moderate agreement between estimation methods. As compared with Euclidean distance, service areas and cost distance may represent a more meaningful characterization of "access" to resources. Each method has tradeoffs in computational resources required versus potential improvement in exposure classification. Careful consideration of the method used for determining "access" will reduce subsequent misclassifications.

Water Energy Food Nexus Analysis and Management Tools: A Review

In order to eradicate water–energy–food poverty, Sustainable Development Goals (SDG) proposed milestones to overcome the feeding problem. The development of water–energy–food (WEF) nexus management tools, and approaches has increased during last years. The aim of this research is to review WEF nexus management methods, tools, and examples to identify gaps, goals, or future development that arise when modelling goods management issues for designing a sustainable development framework. It is also presented the food–biofuel competition for resources problem focusing in threatened systems. In addition to the resource trade-off quantification issue, it proposed an analysis for WEF systems management from economic, environmental, and practical points of view with the aim of identifying results, challenges, gaps, or assumptions for nexus. The renewable energy highlights as an enabler for sustainable development.

Resources and predation: drivers of sociality in a cyclic mesopredator

In socially flexible species, the tendency to live in groups is expected to vary through a trade-off between costs and benefits, determined by ecological conditions. The Resource Dispersion Hypothesis predicts that group size changes in response to patterns in resource availability. An additional dimension is described in Hersteinsson’s model positing that sociality is further affected by a cost–benefit trade-off related to predation pressure. In the arctic fox (Vulpes lagopus), group-living follows a regional trade-off in resources’ availability and intra-guild predation pressure. However, the effect of local fluctuations is poorly known, but offers an unusual opportunity to test predictions that differ between the two hypotheses in systems where prey availability is linked to intra-guild predation. Based on 17-year monitoring of arctic fox and cyclic rodent prey populations, we addressed the Resource Dispersion Hypothesis and discuss the results in relation to the impact of predation in Hersteinsson’s model. Group-living increased with prey density, from 7.7% (low density) to 28% (high density). However, it remained high (44%) despite a rodent crash and this could be explained by increased benefits from cooperative defence against prey switching by top predators. We conclude that both resource abundance and predation pressure are factors underpinning the formation of social groups in fluctuating ecosystems.

Entrepreneurial organizing activities and nascent venture performance

This research provides an improved understanding of how ventures successfully organize via resource allocations. Conceptually, we apply elements of action theory to account for resource trade-offs that occur as entrepreneurs make decisions about adding staff members to boundary spanning, technical core, and management functions. We then model how these allocation decisions differentially impact nascent venture performance. Empirically, we test our model with a sample of 2484 entrepreneurs captured in the Kauffman Firm Survey, a longitudinal dataset that tracks a random sample of US startups over an 8-year period. Results from dynamic panel estimation reveal evidence of both performance penalties and performance boosts as the result of entrepreneurs adding staff to specific areas, revealing optimality in specific configurations of entrepreneurial organizing elements.

From canopy to single flowers: a downscale approach to flowering of the invasive species

Context Acacia longifolia is a native legume of south-eastern Australia and Tasmania and is invasive in many parts of the world. A key feature to its success is the production of a high quantity of flowers every season, resulting in a massive seedbank that remains dormant in the soil for decades. Many studies have been performed on this species’ reproductive biology, but none has focused on flowering in detail. Aims Our main objective was to understand this species’ resource allocation strategy that ensures its successful reproduction in the invasive range. Methods We developed an integrative approach, assessing flowering at different levels, namely, canopy and branch flowering (macro scale), downscaling to individual flower functional stages and their duration, pollen longevity and stigma receptivity (micro scale). We performed this study in three different locations in sand dunes along the Portuguese coast with different environmental conditions. Key results Canopy flowering shows no difference among sites. Pollen and stigma assessment showed that this species is protogynous, with the stigma being highly receptive long before pollen is released. Once released, pollen lasts roughly 72 h. Individual flowers are relatively short-lived, with a rapid progression from closed flower buds to fully open flowers. Implications Our results indicated that A. longifolia has a resource trade-off strategy of investing in flowers and pollen that are relatively short-lived, which are counterbalanced by their massive quantities.

Stakeholder Perspectives on Returning Nonactionable Apolipoprotein L1 (APOL1) Genetic Results to African American Research Participants.

APOL1 results should be offered to participants. Responsibly fulfilling this offer requires careful identification of best communication practices, broader education about the topic, and ongoing community engagement.

Groundwater-sourced irrigation and agro-power subsidies: Boon or bane for small/marginal farmers in India?

Growing inequity in access to sustainable irrigation supply services, groundwater and electricity in particular, has become core agendas in many recent global development dialogues on account of food/nutritional security, ensuring on-farm livelihood opportunities, rural poverty alleviation and development. Herein, we aim to present a nation-wide appraisal of eco-environmental and socioeconomic ramifications of subsidizing farm-power services in India, to highlight future requirements to conserve groundwater reserves so as to ensure sustainable irrigation supply services. We adopted a mixed method approach, coupling secondary data analysis (obtained from various governmental archives), with a systematic review of relevant global literature. For the latter, we adopted a multi-stage PRISMA method (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) to summarize observations from post-2000 literature. Our results indicate that, over the years, groundwater has emerged as the mainstay of the irrigation sector in India (via millions of tube/bore wells), replacing surface-water systems (canals). However, unsustainable groundwater drafting has led to (i) significant groundwater drawdowns in most Indian states; (ii) exacerbated greenhouse gas emissions; and (iii) caused extensive soil-water salinization, which impede sustainable agrarian/rural development on long-run. Current literature, however, suggests that, unsustainable groundwater drafting is indulged at policy level only by (i) relaxed groundwater tariffing scheme, and (ii) lucrative agro-power subsidies – collectively which offer the farmers free reign to draft groundwater at will. We reflect on the rise of groundwater market, leading to disproportionate access to groundwater for irrigation, and tragedy of the less-endowed sections of the famring communities. We urge the concerned authorities to devise and implement strategic institutional reforms to bolster the agro-power subsidy delivery mechanisms, and reflect on opportunities of nationwide adoption of feeder channel segregation (FCS) and initiate minimum energy support (MES) schemes. The idea is to make the agro-energy sector more efficient (based on notions of equity, fairness and transparency for all to access the benefits. In the final section we urge the authorities to adopt a systems' thinking approach to identify the key barriers to on-ground implementation of FCS and MES; introduce smart metering system, and above all, incorporate the water-food-energy nexus application in mainstream decision making for irrigation services. The idea is to identify/develop means of resource co-management, identify synergies and trade-off, within a unified framework of irrigation systems’ governance that balances resources supply and demand, without endangering the ecosystem services. We also outline potential research directions; emphasize on need of targeted, process-level investigations with increased case studies, and urge the authorities for improved data dissemination and accessibility.

An Integrated Approach to Peace and Resource Security

This paper explores the value proposition of using systems tools to model the interlinkages that exist between the security of water, energy, land, and food (WELF) resources and peace. The intersection between these five sectors, referred to as the WELF-Peace nexus, is complex, unfolds in a constrained landscape of specific context and scale, and involves the interaction of multiple systems and their subsystems. Multiple states of combined community peace and resource security are possible. This paper demonstrates the value proposition of using system dynamics to account for the interdependencies that exist between the four sectors of the WELF nexus and the domains of positive peace. Two existing indices, the Positive Peace Index and the Pardee RAND Food-Energy-Water (FEW) Security Index proposed by the Institute for Economy and Peace (IEP) are considered, and their interaction analyzed using system dynamics. The approach can be used to explore different scenarios involving linkages between positive peace and different forms of FEW resource synergy and tradeoff.

Emergent correlations in gene expression dynamics as footprints of resource competition.

Genetic circuits need a cellular environment to operate in, which naturally couples the circuit function with the overall functionality of gene regulatory network. To execute their functions, all gene circuits draw resources in the form of RNA polymerases, ribosomes, and tRNAs. Recent experiments pointed out that the role of resource competition on synthetic circuit outputs could be immense. However, the effect of complexity of the circuit architecture on resource sharing dynamics is yet unexplored. In this paper, we employ mathematical modelling and in-silico experiments to identify the sources of resource trade-off and to quantify its impact on the function of a genetic circuit, keeping our focus on regulation of immediate downstream proteins, which are often used as protein read-outs. We show that estimating gene expression dynamics from readings of downstream protein data might be unreliable when the resource is limited and ribosome affinities are asymmetric. We focus on the impact of mRNA copy number and ribosome binding site (RBS) strength on the nonlinear isocline that emerges with two regimes, prominently separated by a tipping point, and study how correlation and competition dominate each other depending on various circuit parameters. Focusing further on genetic toggle circuit, we have identified major effects of resource competition in this model motif and quantified the observations. The observations are testable in wet-lab experiments, as all the parameters chosen are experimentally relevant.