Group Size Research Articles

Blouch: Bayesian Linear Ornstein-Uhlenbeck Models for Comparative Hypotheses.

Relationships among species in the tree of life can complicate comparative methods and testing adaptive hypotheses. Models based on the Ornstein-Uhlenbeck process permit hypotheses about adaptation to be tested by allowing traits to either evolve towards fixed adaptive optima (e.g., regimes or niches) or track continuously changing optima that can be influenced by other traits. These models allow estimation of the effects of both adaptation and phylogenetic inertia - resistance to adaptation due to any source - on trait evolution, an approach known as the "adaptation-inertia" framework. However, previous applications of this framework, and most approaches suggested to deal with the issue of species non-independence, are based on a maximum likelihood approach and thus it is difficult to include information based on prior biological knowledge in the analysis, which can affect resulting inferences. Here I present Blouch, (Bayesian Linear Ornstein-Uhlenbeck Models for Comparative Hypotheses), which fits allometric and adaptive models of continuous trait evolution in a Bayesian framework based on fixed or continuous predictors and incorporates measurement error. I first briefly discuss the models implemented in Blouch, and then the new applications for these models provided by a Bayesian framework. This includes the advantages of assigning biologically meaningful priors when compared to non-Bayesian approaches, allowing for varying effects (intercepts and slopes), and multilevel modeling. Validations on simulated data show good performance in recovering the true evolutionary parameters for all models. To demonstrate the workflow of Blouch on an empirical dataset, I test the hypothesis that the relatively larger antlers of larger bodied deer are the result of more intense sexual selection that comes along with their tendency to live in larger breeding groups. While results show that larger bodied deer that live in larger breeding groups have relatively larger antlers, deer living in the smallest groups appear to have a different and steeper scaling pattern of antler size to body size than other groups. These results are contrary to previous findings and may argue that a different type of sexual selection or other selective pressures govern optimum antler size in the smallest breeding groups.

Post-collaborative benefits: A meta-analysis of the effect of collaboration on subsequent individual retrieval.

Collaboration has an essential role in memory, and how to appropriately use it to affect individual memory positively is a matter of concern. The meta-analysis generally assessed the effect of collaboration on subsequent individual retrieval, registered on the PROSPERO platform and adhering to the PRISMA guidelines, using the Web of Science, Science Direct, CNKI and WanFang databases with post-collaborative memory as the main subject, screened studies published up to December 31, 2023, a total of 64 studies with 101 effect sizes, including 13,398 participants from 11 countries. Heterogeneity test, sensitivity analysis, subgroup analysis and meta-regression analysis were performed on the included studies, while publication bias was assessed. The results found that collaboration improves subsequent individual retrieval memory more than individuals, and collaboration has a moderate facilitating effect on subsequent individual retrieval. Group size, material category, category size, collaboration phase, collaboration approach, task process and test method were among the moderating variables. The study emphasizes the role of collaboration in cognition and demonstrates the post-collaborative benefits. The conclusions are of value for developing methods to improve individual memory.

Reliable prediction of implant size and axial alignment in AI-based 3D preoperative planning for total knee arthroplasty

The size and axial alignment of prostheses, when planned during total knee replacement (TKA) are critical for recovery of knee function and improvement of knee pain symptoms. This research aims to study the effect of artificial intelligence (AI)-based preoperative three dimensional (3D) planning technology on prosthesis size and axial alignment planning in TKA, and to compare its advantages with two dimensional (2D) X-ray template measurement technology. A total of 60 patients with knee osteoarthritis (KOA) who underwent TKA for the first time were included in the AI (n = 30) and 2D (n = 30) groups. The preoperative and postoperative prosthesis size, femoral valgus correction angle (VCA) and hip-knee-ankle angle (HKA) were recorded and compared between the two groups. The results of the University of Western Ontario and McMaster University Osteoarthritis Index (WOMAC) and the American Knee Association Score (AKS) were evaluated before surgery, 3 months, 6 months, and 12 months after surgery. The accuracy of prosthesis size, VCA and HKA prediction in AI group was significantly higher than that in 2D group (P < 0.05). The WOMAC and AKS scores in AI group at 3 months, 6 months and 12 months after surgery were better than those in 2D group (P < 0.05). Both groups showed significant improvement in WOMAC and AKS scores at 12 months follow-up. AI-based preoperative 3D planning technique has more reliable planning effect for prosthesis size and axial alignment in TKA.

Asymmetrical, symmetrical and artifactual man: group size and cooperation in James Buchanan’s constitutional economics

Abstract Economics is frequently criticised for relying on a narrow and limited view of human beings. This may be particularly true of economic analyses of non-market decisions in which individuals often appear reduced to self-interested automata who maximise a given objective function. In this article, we show that the approach of one of the founders of public choice and constitutional political economy, James Buchanan, contradicts this view. Even though he assumed individuals were rational and self-interested, Buchanan nevertheless had a sophisticated view of human nature. He distinguished between a natural and artifactual man, but also between (what we term) symmetrical and asymmetrical man. This is not only important to demonstrate the richness of the ontology of an influential economist, but also because, we also show, Buchanan’s public choice and constitutional economics cannot be understood without a reference to this ontology.

Collective intelligence facilitates emergent resource partitioning through frequency-dependent learning.

Deciding where to forage must not only account for variations in habitat quality but also where others might forage. Recent studies have suggested that when individuals remember recent foraging outcomes, negative frequency-dependent learning can allow them to avoid resources exploited by others (indirect competition). This process can drive the emergence of consistent differences in resource use (resource partitioning) at the population level. However, indirect cues of competition can be difficult for individuals to sense. Here, we propose that information pooling through collective decision-making-i.e. collective intelligence-can allow populations of group-living animals to more effectively partition resources relative to populations of solitary animals. We test this hypothesis by simulating (i) individuals preferring to forage where they were recently successful and (ii) cohesive groups that choose one resource using a majority rule. While solitary animals can partially avoid indirect competition through negative frequency-dependent learning, resource partitioning is more likely to emerge in populations of group-living animals. Populations of larger groups also better partition resources than populations of smaller groups, especially in environments with more choices. Our results give insight into the value of long- versus short-term memory, home range sizes and the evolution of specialization, optimal group sizes and territoriality. This article is part of the theme issue 'Connected interactions: enriching food web research by spatial and social interactions'.

Examining the Use of DanMu for Crowdsourcing Control in Virtual Gatherings

The advent of web-based interactive technologies has opened up new possibilities for virtual gatherings in 3D environments. Live-streaming, in particular, has gained increasing attention due to its effectiveness in engaging a large number of users in collective online activities. With an emphasis on audience participation, live-streaming shares common characteristics of the outlook of the metaverse and is driving new waves of interaction in virtual gatherings, such as engaging users through crowdsourcing control. However, this type of social interaction has not been examined in the Asian context, and it lacks systematic investigation of user experience with different crowdsourcing control methods. In this paper, we present a novel crowdsourcing control method based on DanMu, the subtitle system of Bilibili, one of the most successful and prevalent live-streaming platforms in Asia. We organized virtual gatherings by live-streaming a Minecraft virtual campus and examined the use of DanMu for crowdsourcing control. Our first study investigated the influence of three crowdsourcing control methods (First Come First Served, Vote, and Super Command) on collective navigation task efficiency and user experience. These influences were further discussed with user activeness and group sizes in a follow-up study. The results showed that Super Command, a representative mode on top of the democratic voting mechanism, offers better user experiences and social richness in large groups. Participants also rated its usability higher in small groups. Besides, virtual gathering in small groups allows greater pragmatic quality, usability, and a sense of agency than in large groups. Our work provides design guidelines for developers and HCI practitioners to develop crowdsourcing control methods and improve novel virtual gathering experiences in virtual worlds and the future metaverse.

Wait-times Benchmarks for risk-based prioritization in Transcatheter Aortic Valve Implantation: a simulation study.

Demand for transcatheter aortic valve implantation (TAVI) has increased in the last decade, resulting in prolonged wait-times and undesirable health outcomes in many health systems. Risk-based prioritization and wait-times benchmarks can improve equitable access to patients. We used simulation models to follow-up a synthetic population of 50,000 individuals from referral to completion of TAVI. Based on their risk of adverse events, patients could be classified as "low-", "medium-" and "high-risk", and shorter wait-times were assigned for the higher risk groups. We assessed the impacts of the size and wait-times for each risk group on waitlist mortality, hospitalization and urgent TAVIs. All scenarios had the same resource constraints, allowing us to explore the trade-offs between faster access for prioritized patients and deferred access for non-prioritized groups. Increasing the proportion of patients categorized as high-risk, and providing more rapid access to the higher-risk groups achieved the greatest reductions in mortality, hospitalizations and urgent TAVIs (relative reductions of up to 29%, 23% and 38%, respectively). However, this occurs at the expense of excessive wait-times in the non-prioritized low-risk group (up to 25 weeks). We propose wait-times of up to 3 weeks for high-risk patients and 7 weeks for medium-risk patients. Prioritizing higher-risk patients with faster access leads to better health outcomes, however this also results in unacceptably long wait-times for the non-prioritized groups in settings with limited capacity. Decision-makers must be aware of these implications when developing and implementing waitlist prioritization strategies.

Estimating the Size and Density of the La Prele Site: Implications for Early Paleoindian Group Size

Estimating the Size and Density of the La Prele Site: Implications for Early Paleoindian Group Size

Patchy energy landscapes promote stability of small groups of active particles

Group formation and coordination are fundamental characteristics of living matter, essential for performing tasks and ensuring survival. Interactions between individuals play a key role in group formation, and the impact of resource distributions is a vibrant area of research. As of now, an understanding of how patchy resource distributions determine group dynamics is not yet fully understood. Studying active particles in controlled optical landscapes as energy sources, we demonstrate a non-monotonic dependency of group size on landscape patchiness, with the smallest groups forming when the patches match the active particles’ size. A similar relationship is observed in terms of group stability, evidenced by a reduced rate of individual exchange in patchy environments compared to homogeneous conditions. Reduced group sizes can be beneficial to optimise resources in heterogeneous environments and to control information flow within populations. Our results provide insights into the role of patchy landscapes and uneven energy distributions in active matter and hold implications for refining swarm intelligence algorithms, enhancing crowd management techniques, and tailoring colloidal self-assembly.

Correction: Effect of group size and period of the day on daily activity patterns of yellow-wattled lapwing Vanellus malabaricus; (Boddaert, 1783) in Northern India

Correction: Effect of group size and period of the day on daily activity patterns of yellow-wattled lapwing Vanellus malabaricus; (Boddaert, 1783) in Northern India

Comparing camera‐based ungulate density estimates: a case study using island populations of bighorn sheep and mule deer

AbstractCamera‐based abundance estimators are an alternative methodology of growing interest in both research and management applications. The statistical formulations of camera‐based abundance estimators using time‐lapse data should theoretically produce precise and unbiased estimates; however, production of unbiased results also requires meeting several important assumptions, and real‐world case studies evaluating such results remain relatively few. We applied instantaneous sampling (IS) and space‐to‐event (STE) estimators to remote camera data collected in April 2021 via time‐lapse sampling of closed populations of bighorn sheep (Ovis canadensis) and mule deer (Odocoileus hemionus) on Wild Horse Island in western Montana, USA, and compared results for bighorn sheep to aerial and ground‐based counts. Point estimates from camera‐based approaches underestimated bighorn sheep populations by 32–44% (IS estimator) and 62–69% (STE estimator) relative to aerial and ground counts. Patchy spatial distribution and group‐living behavior of sheep resulted in a high degree of noise surrounding the IS estimate. In comparison, a low point estimate with relatively narrow confidence intervals suggested potential sensitivity of the STE estimator to violating assumptions of independence among individual animals and sampling occasions. Estimates of mule deer had improved precision over sheep estimates, as indicated by lower estimated coefficients of variation of the mean (CVmean) derived from the analytic SE estimator. Using 15‐m viewsheds and the IS estimators, mule deer density estimates came with a 26% CVmean compared to 43% CVmean for bighorn sheep. This discrepancy may be a result of differences in distribution, behavior, and relative abundance between the 2 species. Accounting for group size and increasing time between sampling may improve accuracy of density estimates and adhere better to model assumptions when estimating precision. In addition, factors influencing viewshed and resulting density extrapolations must be considered carefully. While camera‐based methods theoretically provide an alternative way to estimate density when traditional methods are impractical, our results suggest that more work is needed to ensure density estimates are accurate and precise enough to inform population management.

Interacting with the farthest neighbor promotes cohesion and polarization in collective motion

The collective behavior generated from self-organization is one of the most prominent characteristics of animal populations. Typically, it is assumed that the interactions between individuals are average and synchronous. However, recent empirical studies have shown that interactions between individuals are selective and update their positions and directions asynchronously. Especially the feature factor of distance is widely used in theoretical modeling, but there is no detailed analysis and discussion on it in pairwise interaction. In this work, the effect of pairwise interactions on group motion is investigated under three distance features: nearest, medium, and farthest, based on a self-propelled particle model and combined with an asynchronous update scheme. The research results indicate that simple pairwise interaction can achieve group-level cohesion, especially by selecting the farthest neighbor instead of only interacting with the nearest neighbor, and the proportion of topological neighbors required to achieve cohesion is independent of the group size. In addition, we found that there is a visual angle range that is conducive to achieving cohesion and consistent movement in the group. This study provides insight into selective interaction, especially the great significance of the distance factor in pairwise interaction.

Clinical observation of the subthreshold micropulse laser combined with ranibizumab for treatment of diabetic macular edema

Objective: To evaluate the efficacy and safety of the subthreshold micropulse laser (SMPL) combined with ranibizumab in treating diabetic macular edema (DME). Methods: This was a prospective randomized controlled study. Patients diagnosed with DME in the Ophthalmology Department of Beijing Hospital were enrolled from January 2020 to December 2022. Patients were randomized in a ratio of 1∶1 using a table of random numbers into the ranibizumab monotherapy group and the SMPL combined with ranibizumab therapy group. We compared the changes of best-corrected visual acuity, central macular thickness measured by optical coherence tomography and optical coherence tomography angiography parameters, including the vessel density of the superficial and deep capillary plexus (DCP), foveal avascular zone size and peripapillary vessel density, at baseline, 6 and 12 months after the treatment. After 12 months of follow-up, fundus fluorescein angiography results, adverse events, and the number of injections or laser therapies were recorded. The Fisher's exact test and group t-test were used for statistical analysis. Results: Seventy-two patients (72 eyes) were enrolled, with a mean age of (61.1±8.2) years. Patients in the combination therapy group included 19 males and 17 females, while patients in the ranibizumab monotherapy group were 17 males and 19 females. There was no statistically significant difference in baseline characteristics between the two groups (P>0.05). A significant improvement in best-corrected visual acuity was shown in both groups at 6 and 12 months [(58.5±12.9) and (58.2±12.2) ETDRS letters in the combination therapy group, and (63.3±13.1) and (63.8±12.5) ETDRS letters in the ranibizumab monotherapy group]. A significant reduction in central macular thickness was shown in both groups at 6 and 12 months [(451.0±185.5) and (380.4±159.3)μm in the combination therapy group, and (387.5±135.5) and (372.8±146.1)μm in the ranibizumab monotherapy group]. However, there was no significant difference between groups at each timepoint (all P>0.05). At 12 months, the vessel density of the superficial capillary plexus showed no statistical difference compared to the baseline value in each group or between groups (42.6%±5.9% in the ranibizumab monotherapy group and 42.2%±5.5% in the combination therapy group, P>0.05). The vessel density of the DCP in the combination therapy group significantly increased to 47.5%±5.6% at 12 months, significantly different from that in the ranibizumab group (43.4%±5.1%; P<0.05). The foveal avascular zone size in the ranibizumab monotherapy group reduced to (0.32±0.13) mm2, significantly different from that in the combination therapy group [(0.34±0.16) mm2] at 12 months (P<0.05). Patients in the ranibizumab monotherapy group received (7.3±2.5) intravitreal injections, while patients in the combination therapy group received 3 injections. No unfavorable outcomes on fundus fluorescein angiography or systemic or topical severe adverse events were observed during the follow-up. Conclusions: The SMPL combined with intravitreal ranibizumab injections was effective and safe in treating DME patients. The combination treatment significantly reduced the number of injections and improved the vessel density of the DCP and macular ischemia, compared to the ranibizumab monotherapy.

The role of regional tax autonomy, firm size, and business groups in tax avoidance: evidence from Spain

ABSTRACT This paper investigates the influence of regional tax autonomy, firm size, and business group affiliation on corporate tax burden in a large sample of Spanish firms, including non-listed firms, from 2007 to 2016. Our findings reveal that firms located in tax-autonomous regions exhibit lower effective corporate tax rates (ETR), providing new empirical support for the horizontal tax competition theory. Additionally, we identify a positive relationship between firm size and corporate tax burden, aligning with the political cost theory. Furthermore, we find that group-affiliated firms face a higher ETR than independent firms, and that group affiliation attenuates the differences in the tax burden experienced by large and small firms.

Pilot epinephrine dose-finding study to counter epidural-related blood pressure reduction

ObjectiveAn unwanted side effect associated with epidural analgesia is the reduction in blood pressure (BP) due to the sympathetic blockade. This study evaluated the hemodynamic effects of adding different epinephrine...

An Online Review Data-Driven Fuzzy Large-Scale Group Decision-Making Method Based on Dual Fine-Tuning

Large-scale group decision-making (LSGDM) involves aggregating the opinions of participating decision-makers into collective opinions and selecting optimal solutions, addressing challenges such as a large number of participants, significant scale, and a low consensus. In real-world scenarios of LSGDM, various challenges are often encountered due to factors such as fuzzy uncertainties in decision information, the large size of decision groups, and the diverse backgrounds of participants. This paper introduces a dual fine-tuning-based LSGDM method using an online review. Initially, the sentiment analysis is conducted on online review data, and the identified sentiment words are graded and quantified into a fuzzy data set to understand the emotional tendencies of the text. Then, the Louvain algorithm is used to cluster the decision-makers. Meanwhile, a method combining Euclidean distances with Wasserstein distances is introduced to accurately measure data similarities and improve clustering performances. During the consensus-reaching process (CRP), a two-stage approach is employed to adjust the scores: to begin with, by refining the scores of the decision representatives via minor-scale group adjustments to generate a score matrix. Then, by identifying the scores corresponding to the minimum consensus level in the matrix for adjustment. Subsequently, the final adjusted score matrix is integrated with the prospect–regret theory to derive the comprehensive brand scores and rankings. Ultimately, the practicality and efficiency of the proposed model are demonstrated using a case study focused on the purchase of solar lamps. In summary, not only does the model effectively extract the online review data and enhance decision efficiency via clustering, but the dual fine-tuning mechanism in the model to improve consensus attainment also reduces the number of adjustment rounds and avoids multiple cycles without achieving the consensus.

Optimizing group work strategies in virtual dissection.

Due to its haptic and interactive nature, virtual anatomy provides an opportunity for small-group learning, enabling students to develop their group work skills before they graduate. However, there is currently little practical guidance supported by pedagogic principles detailing how to incorporate it into curricula. Anatomy educators at the University of Plymouth conducted action research aiming to capture students' overall perceptions of the virtual anatomy platform Anatomage. Questioning the benefits and challenges students face while interacting with Anatomage prompted the creation of evidence-based interventions to be later evaluated. Although a plethora of themes were identified, this report specifically examines those relating to group work. Thematic analysis of initial focus group data found group size and group dynamics impacted students' experience with the platform. Following the implementation of interventions to resolve these issues, a questionnaire and second series of focus groups were conducted to determine whether they were successful. Additional subthemes found from these data included facilitation, social pressure, peer learning and working with friends. This study contributed to the improvement of small group learning and integration of virtual anatomy into curricula based on student and staff feedback. As such, these data support the development of effective group working skills which are fundamental for healthcare professionals and widely recognized by regulators such as the General Medical Council and Health and Care Professions Council. In this report, the authors provide practical advice informed by pedagogy and principles from management and psychology to provide a multidisciplinary perspective.

Optimizing group work strategies in virtual dissection.

Due to its haptic and interactive nature, virtual anatomy provides an opportunity for small-group learning, enabling students to develop their group work skills before they graduate. However, there is currently little practical guidance supported by pedagogic principles detailing how to incorporate it into curricula. Anatomy educators at the University of Plymouth conducted action research aiming to capture students' overall perceptions of the virtual anatomy platform Anatomage. Questioning the benefits and challenges students face while interacting with Anatomage prompted the creation of evidence-based interventions to be later evaluated. Although a plethora of themes were identified, this report specifically examines those relating to group work. Thematic analysis of initial focus group data found group size and group dynamics impacted students' experience with the platform. Following the implementation of interventions to resolve these issues, a questionnaire and second series of focus groups were conducted to determine whether they were successful. Additional subthemes found from these data included facilitation, social pressure, peer learning and working with friends. This study contributed to the improvement of small group learning and integration of virtual anatomy into curricula based on student and staff feedback. As such, these data support the development of effective group working skills which are fundamental for healthcare professionals and widely recognized by regulators such as the General Medical Council and Health and Care Professions Council. In this report, the authors provide practical advice informed by pedagogy and principles from management and psychology to provide a multidisciplinary perspective.

Cytotoxicity and Genotoxicity Effects of a Magnetic Zeolite Composite in Daphnia magna (Straus, 1820)

Zeolite type 5A combined with the magnetic properties of maghemite nanoparticles facilitate the rapid absorption of heavy metals, which makes them an interesting proposal for the remediation of water contaminated with lead and arsenic. However, the physicochemical analysis related to concentration and size for the use of this magnetic zeolite composite (MZ0) in water bodies and the possible toxicological effects on aquatic fauna has not yet been carried out. The main objective of the research work is to determine lethal concentrations that cause damage to Daphnia magna based on LC50 tests, morphology, reproductive rate, and quantification of the expression of three genes closely involved in the morphological development of vital structures (Glass, NinaE, Pph13). To achieve this objective, populations of neonates and young individuals were used, and results showed that the LC50 for neonates was 11,314 mg L−1, while for young individuals, it was 0.0310 mg L−1. Damage to morphological development was evidenced by a decrease in eye size in neonates, an increase in eye size in young individuals, variations in the size of the caudal spine for both age groups, and slight increases in the heart size, body, and antenna for both age groups. The reproductive rate of neonates was not affected by the lower concentrations of MZ0, while in young individuals, the reproductive rate decreased by more than 50% from the minimum exposure concentration of MZ0. And for both ages, Glass gene expression levels decreased as the MZ0 concentration increased. Also, the MZ0 evidenced its affinity for the exoskeleton of D. magna, which was observed using both light microscopy and electron microscopy. It is concluded that MZ0 did not generate significant damage in the mortality, morphology, reproductive rate, or gene expression in D. magna at lower concentrations, demonstrating the importance of evaluating the possible impacts on different life stages of the cladoceran.

Cytotoxicity and Genotoxicity Effects of a Magnetic Zeolite Composite in Daphnia magna (Straus, 1820)

Zeolite type 5A combined with the magnetic properties of maghemite nanoparticles facilitate the rapid absorption of heavy metals, which makes them an interesting proposal for the remediation of water contaminated with lead and arsenic. However, the physicochemical analysis related to concentration and size for the use of this magnetic zeolite composite (MZ0) in water bodies and the possible toxicological effects on aquatic fauna has not yet been carried out. The main objective of the research work is to determine lethal concentrations that cause damage to Daphnia magna based on LC50 tests, morphology, reproductive rate, and quantification of the expression of three genes closely involved in the morphological development of vital structures (Glass, NinaE, Pph13). To achieve this objective, populations of neonates and young individuals were used, and results showed that the LC50 for neonates was 11,314 mg L−1, while for young individuals, it was 0.0310 mg L−1. Damage to morphological development was evidenced by a decrease in eye size in neonates, an increase in eye size in young individuals, variations in the size of the caudal spine for both age groups, and slight increases in the heart size, body, and antenna for both age groups. The reproductive rate of neonates was not affected by the lower concentrations of MZ0, while in young individuals, the reproductive rate decreased by more than 50% from the minimum exposure concentration of MZ0. And for both ages, Glass gene expression levels decreased as the MZ0 concentration increased. Also, the MZ0 evidenced its affinity for the exoskeleton of D. magna, which was observed using both light microscopy and electron microscopy. It is concluded that MZ0 did not generate significant damage in the mortality, morphology, reproductive rate, or gene expression in D. magna at lower concentrations, demonstrating the importance of evaluating the possible impacts on different life stages of the cladoceran.