Larger Group Sizes Research Articles

Explosive information spreading on higher-order networks: the effect of social reinforcement

Abstract Information spreading has been investigated for many years, but the mechanism of why the information explosively catches on overnight is still under debate. This explosive spreading phenomenon was usually considered driven separately by social reinforcement or higher-order interactions. However, due to the limitations of empirical data and theoretical analysis, how the higher-order network structure affects the explosive information spreading under the role of social reinforcement has not been fully explored. In this work, we propose an information-spreading model by considering the social reinforcement on real and synthetic higher-order networks, describable as hypergraphs. Depending on the average group size (hyperedge cardinality) and node membership (hyperdegree), we observe two different spreading behaviors: (i) The spreading progress is not sensitive to social reinforcement, resulting in the information localized in a small part of nodes; (ii) a strong social reinforcement will promote the large-scale spread of information and induce an explosive transition. Moreover, a large average group size and membership would be to the benefit of the appearance of the explosive transition. Further, we display that the heterogeneity of the node membership and group size distributions benefit the information spreading. Finally, we extend the group-based approximate master equations to verify the simulation results. Our findings may help us to comprehend the rapidly information-spreading phenomenon in modern society.

Invited review: Social housing of dairy calves: management factors affecting calf behavior, performance, and health - A systematic review.

Given increasing adoption of social housing for pre-weaned dairy calves, we conducted a systematic review to summarize existing literature describing effects of social housing management factors on behavior, performance, and health of dairy calves. Included articles addressed interventions applied to pre-weaned, socially housed dairy calves, encompassing age at introduction to social housing, group composition (size, stocking density, within-group age range, stability), and housing environment (space allowance, enrichment provision). Outcome measures addressed behavior, including social behavior, locomotor behavior, feeding behavior, abnormal oral behavior, and behavioral responses during tests; performance, including body measurements and weight gain; and health, including clinical health scores and mortality rate. We conducted searches initially targeting any study where dairy calves were housed socially, using Web of Science and PubMed, and subsequently identified a total of 46 relevant studies. Studies investigating age at introduction to pairs or small social groups of 3 to 7 calves (8 experimental studies) suggested possible behavioral and performance benefits, with no negative effects, of earlier introduction to small groups. Earlier introduction to larger groups (assessed in 6 experimental studies and 4 cross-sectional studies) appeared to increase latency to use an automated milk feeder with short-term negative effects on milk intake, yet no evidence of growth effects and variable health effects. Studies investigating effects of group size (assessed in 8 experimental studies and 6 cross-sectional studies) suggested that small social groups may facilitate increased feeding time, with neutral or positive effects on growth and health. Other aspects of group composition, including within-group age range, group stability, and feeder stocking density, were assessed in few experimental studies (7 total), with some results suggesting behavioral benefits of reducing competition for feed and maintaining stable groups. Experimental and cross-sectional studies yielded conflicting findings with respect to health effects of group composition, but results generally suggested possible health risks associated with larger group sizes and within-group age ranges, management factors consistent with the use of dynamic groups. Increasing space allowance (assessed in 6 experimental studies and 6 cross-sectional studies) increased locomotor activity/play behavior and had neutral or positive health effects. Provision of enrichment items (e.g., brushes, combinations of items for oral manipulation; assessed in 5 studies) was found to reduce cross-sucking. Overall, this review describes varied dairy calf social housing management practices which have implications for behavior, performance, and health. Further work is needed to address gaps in knowledge, including long-term effects and variability at the individual and group level, and to establish the external validity of these findings in commercial settings.

The Expression of Teacher Professional Burnout in Lithuanian Preschool Education

Burnout by educators of educational institutions is already a vital problem in some national education systems. Lithuania is not an exception. The current research concentrates on the situation of preschool teaching, as there is a lack of research investigating this particular group of teachers. Taking into account the fact that professional burnout syndrome begins imperceptibly, but later causes serious consequences not only for the educator himself/herself but also for the entire educational process, it is appropriate to conduct a research that aims to evaluate the manifestation of the burnout syndrome expressions of Lithuanian preschool teachers. Research methods: analysis of the scientific literature, quantitative research approach, aiming to evaluate the expression of professional burnout of pedagogues of Lithuanian preschool education institutions. Data were collected while using questionnaire survey the sample consists of respondents who represent the studied population, i.e. educators of preschool education institutions in Lithuanian cities and districts. During the quantitative research survey, 240 preschool teachers were interviewed. The results of the research showed that approximately one out of seven preschool education teachers experience severe burnout. The were revealed the major issues of the nature of professional burnout, highlighting its complexity, involving increasing emotional and physical fatigue, depersonalization, and decreased professional aspirations. Factors such as age, qualification category, and working hours also have influence on the professional burnout level. Management factors such like heavy workloads, poor relationships among the teachers and administration, large group sizes contribute to teacher burnout. These factors have direct impact on the interactions with children, parents, colleagues, and managers. Burnout reduces motivation, organizational ability, and can lead to job dissatisfaction and workplace changes. Additionally, the negative impact on the educational process, such as creating an unfavourable learning environment and increasing the workload for other staff may be cleared out.

A Study on Diet Composition and Feeding Habits of Sphyraena putnamae Jordan & Seale, 1905 from the Northern Arabian Sea

The food and feeding habits of the Sphyraena putnamae (n=381) ranging from 16 to 99 cm were investigated the Karachi coast, the Northern Arabian Sea, Pakistan. S. putnamae consumed various prey items, which were divided into three categories: teleosts, molluscs, and crustaceans. Molluscs and crustaceans were the second preferred food component rather than teleost. The major constituents of the teleost group on basis of their ascendancy, were identified to be (dorosomatids; sciaenids; leiognathids; platycephalids; engraulids; carangids; bregmacerotids; nemipterids; scombrids; and synodontids). The empty stomach ratio and stomach fullness index did not differ significantly between the sexes and size classes. The stomach fullness index of juvenile barracudas (16-29 cm in length) was significantly higher as compared to adults in the medium (30-55 cm) and large (56-99 cm) size groups. Additionally, an analysis of dietary preferences revealed that small (juvenile) barracudas (16-29 cm) primarily consumed crustaceans, while medium-sized individuals (30-55 cm) preferred mollusks, and large individuals (56-99 cm) favoured teleost. The present study provides detailed information on the feeding ecology of the S. putnamae, for the first time from the Pakistan coast that will be useful for understanding trophodynamics of species developing effective management and conservation measures, ensuring the species' long-term viability.

Dosimetric evaluation of different cylinder diameters in three-dimensional vaginal brachytherapy for early-stage endometrial cancer

PurposeTo evaluate the dosimetric, radiobiological, and toxicity differences between different cylinder diameters (d) in high-dose-rate three-dimensional computed-tomography-guided vaginal brachytherapy (VBT) for early-stage endometrial cancer (EC).MethodsFrom January 2019 to January 2024, postoperative EC patients treated with exclusive VBT using cylinders were classified by the cylinder diameter (d ≤ 2.6 cm: small-size; d ≥ 3.0 cm: large-size) and matched according to 1:2 propensity score matching. Vaginal clinical target volume (CTV) was a 3-mm expansion around the cylinder surface. Dosimetric parameters in equivalent dose in 2 Gy (EQD2) (α/β = 3 Gy) and equivalent uniform dose (EUD) of vaginal_CTV and organs at risk (OARs) were evaluated. Urinary, gastrointestinal, and vaginal toxicities were assessed using CTCAE v5.0.ResultsAfter matching, 132 patients (small-size: 44; large-size: 88) were analyzed. For vaginal_CTV, the small-size group had higher doses to 2%, 5%, 0.1 cc, 1 cc, and 2 cc of the volume (D2, D5, D0.1 cc, D1cc, and D2cc) than the large-size group while lower doses to the 95%, 98%, and 100% volume (D95, D98, and D100). The D2cc and D5cc of bladder and all dosimetric parameters of rectum were smaller in the small-size group. The EUD of vaginal_CTV, bladder, and rectum showed no significant differences. No significant differences in toxicities were found within the median follow-up of 26.8 months.ConclusionCylinders with smaller diameters produced more nonuniform dose distributions in the target and delivered lower doses to bladder and rectum than large-size cylinders. However, the dosimetric differences did not translate into significant differences of radiobiological parameters or outcomes.

A Comparative Analysis of Drone and Boat Monitoring for the Endangered Bolivian River Dolphin

Accurate population monitoring is essential for effective wildlife conservation. This study compares the effectiveness of drone-based vs traditional boat-based methods for assessing an endangered Bolivian river dolphin (Inia geoffrensis boliviensis; BRD) population in Bolivia. Data were collected using high-resolution video recorded with a DJI Mavic 2 zoom drone and standardized methodologies for boat surveys. Two mixed-effects linear models incorporating Poisson and negative binomial error structures were used to compare counts obtained from drone- and boat-based surveys. Results show that drone-based surveys detected 1.15% more individuals on average than boat-based surveys. Drone counts were higher at sites with larger group sizes, leading to congruent estimates. The aerial perspective that drones offer lets researchers overcome potential challenges from boat-based surveys—for example, difficulties related to confirming individual IDs because of limited visibility due to sun glare. Transitioning from boat- to drone-based surveys offers advantages such as reduced disturbance from placement closer to the animals and improved detection rates. Ethical considerations and responsible flight practices are crucial. Standardizing methodologies and prioritizing ethical research factors are key for successful implementation. Drone-based surveys offer a promising approach to enhance wildlife monitoring and conservation practices. This study is the first of this kind for Bolivia, a national natural heritage site, and contributes to the conservation and knowledge of the BRD.

The upsides to working with a lap book as a study aid

This research assesses the utility of lap books as a didactic aid in teaching crowded classrooms with specific reference to the participation level and academic achievement. The study was carried out over three terms of high school English classes in a school in Quito, Ecuador; the assessment of results was done both through oral lessons and by end-term written tests. Results also reveal that lap books foster better performance in tests in terms of an increased number of high scores and reduced lower scores in subsequent years. Combining constructivist learning and differentiation as a teaching approach, lap books enhance student participation as well as foster individual learning styles that make the content more easily understandable and retained. The change that was observed across terms indicates improved overall performance, and the existence of lap books facilitated equality in terms of high grades. Consequently, based on such findings made in this study, it is recommended that the development and use of lap books can be adopted as a more conceptually appealing approach for enhancing students’ learning in situations where a more direct form of one student/teacher ratio, interaction is due to large group sizes.

Cooperation in the face of crisis: effect of demographic noise in collective-risk social dilemmas.

In deciding whether to contribute to a public good, people often face a social dilemma known as the tragedy of the commons: either bear the cost of promoting the collective welfare, or free-ride on the efforts of others. Here, we study the dynamics of cooperation in the context of the threshold public goods games, in which groups must reach a cumulative target contribution to prevent a potential disaster, such as an environmental crisis or social unrest, that could result in the loss of all private wealth. The catch is that the crisis may never materialize, and the investment in the public good is lost. Overall, higher risk of loss promotes cooperation, while larger group size tends to undermine it. For most parameter settings, free-riders (defectors) cannot be eliminated from the population, leading to a coexistence equilibrium between cooperators and defectors for infinite populations. However, this equilibrium is unstable under the effect of demographic noise (finite population), since the cooperator-only and defector-only states are the only absorbing states of the stochastic dynamics. We use simulations and finite-size scaling to show that cooperators eventually die off and derive scaling laws for the transient lifetimes or half-lives of the coexistence metastable state. We find that for high risk, the half-life of cooperators increases exponentially with population size, while for low risk, it decreases exponentially with population size. At the risk threshold, where the coexistence regime appears in a discontinuous manner, the half-life increases with a power of the population size.

Comparison of the effects of pre-dilatation with conventional versus larger balloon sizes on clinical outcomes in transcatheter aortic valve implantation with self-expandable valves

Abstract Background Transcatheter aortic valve implantation (TAVI) is considered an established treatment option for patients with severe aortic stenosis. When implanting self-expandable valve, pre-dilatation is often necessary to facilitate optimal transcatheter heart valve (THV) deployment. Traditionally, balloon sizes chosen for pre-dilatation are smaller than the minimum annulus diameter. Insufficient pre-dilatation can result in under-expansion of the THV, necessitating post-dilatation, and can increase the risk of complications. However, this conventional approach may not always yield the best outcomes, prompting a reassessment of balloon sizing strategies to improve procedural success and patient outcomes. Purpose The aim of this study was to investigate the impact on procedural outcomes of using larger balloons, sized less than the mean annulus diameter, for pre-dilatation compared to the traditional practice of using balloons sized less than the minimum annulus diameter during the implantation of self-expandable valves. Methods We analyzed 785 patients who underwent TAVI with self-expandable valve with pre-dilatation out of a consecutive 3880 cases at 6 centers from 2010 to 2023 (Figure 1). Among them, we divided the patients into two groups: those who underwent pre-dilation with balloons smaller than the minimum annulus diameter defined as the Conventional-size group and those who underwent pre-dilatation with balloons smaller than the mean annulus diameter defined as the Large-size group. The primary endpoint of this study was procedural success, stroke and need for permanent pacemaker implantation as designated by the VARC-3criteria. Results Of patients (69% female; mean age 84.9), there were 563 (71.7%) patients in the Conventional-size group and 222 (28.2%) patients in the Large-size group. There was no annulus rupture in either group. The incidence of post-dilatation was significantly higher in the Conventional-size group than in the Large-size group (109 of 563 [19.4%] vs. 23 of 222 [10.3%], p=0.001) (Figure 2). There was no significant difference in the incidence of primary endpoints (all p > 0.05). In post-echocardiographic outcomes, there was no significant difference in effective orifice area, mean pressure gradient, patients-prosthesis mismatch, or paravalvular leakage between the groups (P > 0.05). Conclusions This study demonstrates that a large-size strategy using a balloon smaller than the mean annulus diameter in the deployment of self-expandable valves is safe and may avoid the need for post-dilatation compared to the traditional strategy using a balloon smaller than the smallest diameter.

Therapeutic angiogenesis for patients with chronic limb-threatening ischemia: promising or hoax?

Chronic limb-threatening ischemia (CLTI) is a critical end-stage disease that leads to high amputation rates. Over the past few decades, therapeutic angiogenesis has attracted a lot of attention as a means to reduce the necessity for amputations. Especially gene- and cell therapy are regarded to as possible treatment modalities to restore the hampered blood flow. So far, early-phase clinical trials often fail to prove a significant clinical improvement in mortality, amputation rate, and ulcer healing but still conclude that therapeutic angiogenesis might be promising as therapy. The subsequent phase III clinical trials based on these indecisive early trials fail consistently to demonstrate clinical benefits leaving the promising early results unvalidated. In this review we will illustrate that designing good trials for CLTI patients is challenging, not in the last place since patients are often not eligible due to strict inclusion criteria. Moreover, in this review, we advocate that clinical trials should be conducted with a low risk of bias and that it is of utmost importance to publish results, regardless of the outcome. It is definitely very concerning that many studies of a lower quality (due to small group size or high chance for bias) reporting positive outcomes are published while good quality trials (often with larger group sizes) are stopped prematurely due to lack of effects and remain unpublished. This keeps the 'promising but not yet proven' image of these therapeutic neovascularization studies alive, with still new groups starting similar trials.

Research on Acoustic Monitoring of Escape of Large Yellow Croaker Cultured in Cages

It is an important problem for large yellow croaker culture to escape due to the damage of net coat. In this study, a horizontal moving fish finder was installed in a cage to monitor large yellow croaker groups with different numbers and body lengths by acoustic means, and the behavioral characteristics of fish groups were observed after the experimental net was damaged by using the nesting method. Through the identification of large yellow croaker group individual, swimming speed, size, direction and other group behavior characteristics, in order to prevent the escape of fish, set green (normal), yellow (ordinary alarm), red (strong alarm) three state display. This study will provide technical support for the more scientific and safe development of large yellow croaker cage culture.

Render help or stand by? The effect of group size on third-party punishment and its neural mechanisms

Third-party punishment (TPP) is the punishment that an individual executes on a violator as a third party or observer to maintain social norms. Many studies have provided insights into the neural mechanisms of third-party punishment in group environments. Still, only some studies have focused on the neural mechanisms of third-party punishment in different group sizes. This study used EEG analysis to explore the effects of group size on third-party punishment and its neural activity characteristics from the context of gain and loss. The results show that the punishment rate and amount of the third party in the small group size and loss context were significantly higher than that in the large group size and gain context. EEG results showed that third-party punishment in small groups induced greater P2 than in large groups. In the loss context, the third-party punishment in the large group size induced more negative LNP and activated more theta band activation than in the small group. The results showed that the motivation of the third party to seek a positive reputation in the small size exceeds the balance of its economic interests and tends to punish the violator for maintaining fair norms. The loss context plays a promoting role in this process. However, in the large size, the third-party consideration of its interests was stronger than the willingness to maintain social norms. This study provided neuroscientific evidence for third-party punishment to maintain fair norms in a group environment and further explanations from neuroscience for understanding Indirect Reciprocity Theory.

The influence of social and spatial processes on the epidemiology of environmentally transmitted pathogens in wildlife: implications for management.

Social and spatial structures of host populations play important roles in pathogen transmission. For environmentally transmitted pathogens, the host space use interacts with both the host social structure and the pathogen's environmental persistence (which determines the time-lag across which two hosts can transmit). Together, these factors shape the epidemiological dynamics of environmentally transmitted pathogens. While the importance of both social and spatial structures and environmental pathogen persistence has long been recognized in epidemiology, they are often considered separately. A better understanding of how these factors interact to determine disease dynamics is required for developing robust surveillance and management strategies. Here, we use a simple agent-based model where we vary host mobility (spatial), host gregariousness (social) and pathogen decay (environmental persistence), each from low to high levels to uncover how they affect epidemiological dynamics. By comparing epidemic peak, time to epidemic peak and final epidemic size, we show that longer infectious periods, higher group mobility, larger group size and longer pathogen persistence lead to larger, faster growing outbreaks, and explore how these processes interact to determine epidemiological outcomes such as the epidemic peak and the final epidemic size. We identify general principles that can be used for planning surveillance and control for wildlife host-pathogen systems with environmental transmission across a range of spatial behaviour, social structure and pathogen decay rates. This article is part of the theme issue 'The spatial-social interface: a theoretical and empirical integration'.

Temporal interaction and its role in the evolution of cooperation.

This research investigates the impact of dynamic, time-varying interactions on cooperative behavior in social dilemmas. Traditional research has focused on deterministic rules governing pairwise interactions, yet the impact of interaction frequency and synchronization in groups on cooperation remains underexplored. Addressing this gap, our work introduces two temporal interaction mechanisms to model the stochastic or periodic participation of individuals in public goods games, acknowledging real-life variances due to exogenous temporal factors and geographical time differences. We consider that the interaction state significantly influences both game payoff calculations and the strategy updating process, offering new insights into the emergence and sustainability of cooperation. Our results indicate that maximum game participation frequency is suboptimal under a stochastic interaction mechanism. Instead, an intermediate activation probability maximizes cooperation, suggesting a vital balance between interaction frequency and inactivity security. Furthermore, local synchronization of interactions within specific areas is shown to be beneficial, as time differences hinder the spread of cross-structures but promote the formation of dense cooperative clusters with smoother boundaries. We also note that stronger clustering in networks, larger group sizes, and lower noise increase cooperation. This research contributes to understanding the role of node-based temporality and probabilistic interactions in social dilemmas, offering insights into fostering cooperation.

The Effects of Monitoring Activities on Loan Defaults in Group-Based Lending Program: Evidence from Vietnam

The aim of this study is to investigate the impact of delegated monitoring by a group leader and peer monitoring by group members on loan defaults in a group-based lending program in Vietnam. The data used in the study were collected from a questionnaire survey of 675 participants involved in a group-based lending program conducted from August to October 2022 in the Mekong River Delta, Vietnam. This group-based lending program employs a unique monitoring system that involves hiring the group leader to supervise the group and encouraging group members to monitor each other. The empirical findings derived from the Probit model indicated that delegated monitoring significantly reduces loan defaults, but there was no evidence supporting the effectiveness of peer monitoring within the group. Additionally, under the delegated monitoring scheme, commissions and group size plays an important role in decreasing loan defaults. The implication of the findings is that the Vietnam Bank for Social Policies (VBSP) could maintain large group sizes to provide incentives for group leaders through commissions to enhance repayment rates.

Ecological and genetic variables co-vary with social group identity to shape the gut microbiome of a pair-living primate.

Primates exhibit diverse social systems that are intricately linked to their biology, behavior, and evolution, all of which influence the acquisition and maintenance of their gut microbiomes (GMs). However, most studies of wild primate populations focus on taxa with relatively large group sizes, and few consider pair-living species. To address this gap, we investigate how a primate's social system interacts with key environmental, social, and genetic variables to shape the GMin pair-living, red-bellied lemurs (Eulemur rubriventer). Previous research on this species suggests that social interactions within groups influence interindividual microbiome similarity; however, the impacts of other nonsocial variables and their relative contributions to gut microbial variation remain unclear. We sequenced the 16S ribosomal RNA hypervariable V4-V5 region to characterize the GM from 26 genotyped individuals across 11social groups residing in Ranomafana National Park, Madagascar. We estimated the degree to which sex, social group identity, genetic relatedness, dietary diversity, and home range proximity were associated with variation in the gut microbial communities residing in red-bellied lemurs. All variables except sex played a significant role in predicting GM composition. Our model had high levels of variance inflation, inhibiting our ability to determine which variables were most predictive of gut microbial composition. This inflation is likely due to red-bellied lemurs' pair-living, pair-bonded social system that leads to covariation among environmental, social, and genetic variables. Our findings highlight some of the factors that predict GMcomposition in a tightly bonded, pair-living species and identify variables that require further study. We propose that future primate microbiome studies should simultaneously consider environmental, social, and genetic factors to improve our understanding of the relationships among sociality, the microbiome, and primate ecology and evolution.

Current social management practices contribute to reproductive failure in zoo-housed guenons

Recent emphasis on reflecting natural behaviour and wild group composition in zoo-housed social animals has resulted in substantial improvement in captive breeding and welfare. We investigated studbook data for four guenon species housed in European zoos to assess the role of zoo management practices in the reproductive success of social species. We hypothesized that group dynamics reflecting wild living, including early social experience, would be associated with greater reproductive success. Our findings are presented in a standardized qualitative risk assessment with an additional certainty measure in the form of literature evidence. We found that greater reproductive success was associated with more potential breeding partners in L’Hoest’s, Roloway and Diana monkeys and with larger group sizes in all species studied here, providing support that mimicking wild group size, composition, and dynamics under captive conditions can improve reproductive success. Unexpectedly, greater reproductive success was associated with earlier first inter-facility transfers in female L’Hoest’s and Diana monkeys, and with more frequent inter-facility transfers in male L’Hoest’s and Diana monkeys. Furthermore, for male Diana monkeys and female and male L’Hoest’s monkeys, mothers with less reproductive and rearing experience tended to produce offspring that in turn had greater reproductive success, hinting at more complex and sex-differentiated mechanisms underlying sub-optimal reproduction in zoo guenons. Our findings highlight the importance of carrying out species-specific studies, and demonstrate that zoo management and husbandry practices can inadvertently impact reproductive success. We recommend that zoos holding guenons consider reducing the number of guenon species they hold in favour of increasing group size to improve reproductive success.

Multidisciplinary perspective on a Finnish general upper-secondary school’s educational change: strengthening and hindering factors

ABSTRACT Sustaining change beyond individual teachers is challenging and understanding factors making educational change effective is needed. We aimed to identify the factors that educators and construction specialists considered influential to educational change of a general upper-secondary school that was under construction and was to meet the pedagogical goals of the concurrently renewed national core curriculum and legislation. The analysis of multidisciplinary interviews (n = 22) conducted during the early phase of the construction process assisted in identifying the factors that the participants perceived as strengthening and hindering educational change. The strengthening factors related to leadership support, collaboration opportunities, and teachers’ professional training, engagement, and transformative agency. The hindrances were constraints that related, for instance, to issues in funding, large group sizes and those that lacked applicable cross-curricular examples. We postulate the need to assist schools and individual teachers in creating conditions for educational change at all levels of municipal education.

Benchmarking of Secure Group Communication schemes with focus on IoT

As Internet of Things (IoT) devices become ubiquitous, they face increasing cybersecurity threats. Unlike standard 1-to-1 communication, the unique challenge posed by n-to-n communication in IoT is that messages must not be encrypted for a single recipient but for a group of recipients. For this reason, using Secure Group Communication (SGC) schemes is necessary to encrypt n-to-n communication efficiently for large group sizes. To this end, the literature presents various SGC schemes with varying features, performance profiles, and architectures, making the selection process challenging. A selection from this multitude of SGC schemes should best be made based on a benchmark that provides an overview of the performance of the schemes. Such a benchmark would make it much easier for developers to select an SGC scheme, but such a benchmark still needs to be created. This paper aims to close this gap by presenting a benchmark for SGC schemes that focus on IoT. Since the design of a benchmark first requires the definition of the underlying business problems, we defined suitable problems for using SGC schemes in the IoT sector as the first step. We identified a common problem for the centralized and decentralized/hybrid SGC schemes, whereas the distributed/contributory SGC schemes required defining an independent business problem. Based on these business problems, we first designed a specification-based benchmark, which we then extended to a hybrid benchmark through corresponding implementations. Finally, we deployed our hybrid benchmark in a typical IoT environment and measured and compared the performance of different SGC schemes. Our findings reveal notable impacts on calculation times and storage requirements without a trusted Central Instance (CI) in distributed/contributory SGC schemes.

Reproductive inefficiency and increased behavioral variation are associated with large group size in the orchid bee, Euglossa dilemma

Orchid bees are the only corbiculate bee lineage that is not obligately eusocial. However, multiple species of orchid bee show facultative sociality, with reproductive division of labor and a social hierarchy effectively enforced by oophagy. Orchid bee species differ in the degree of reproductive skew in social groups, as well as the rigidity of social roles. In the orchid bee Euglossa dilemma, previous observation of social groups of two or three individuals found that reproductive skew was complete, with one clear dominant individual that ate and replaced each subordinate laid egg. Here, we compare patterns of egg laying and egg-replacement between typical social nests of 2–3 individuals and larger social nests of 4–5 individuals. We find a striking difference in the reproductive behavior of colonies of varying group size; larger nests exhibit more reproductive inefficiency and conflict over the dominant social position, characterized by repeated oophagy and slower egg replacement. Our findings are consistent with the hypothesis that group size in E. dilemma may be limited by the ability of dominant bees to keep up with egg replacement. We discuss the possible causes and consequences of observed behavioral variation and its implications for understanding social behavior in orchid bees.