Hasil untuk "Competition"

B. Casper, R. B. Jackson

P. Stockley

A. Griffin, S. West, A. Buckling

R. Blake, N. Logothetis

S. Winter

L. McCook, J. Jompa, G. Diaz-Pulido

Augustine A. Lado, Nancy G. Boyd, Susannah Hanlon

S. Schwinning, J. Weiner

D. Tilman

E. Pianka

Ginestra Bianconi, A. Barabási

The rate at which nodes in a network increase their connectivity depends on their fitness to compete for links. For example, in social networks some individuals acquire more social links than others, or on the www some webpages attract considerably more links than others. We find that this competition for links translates into multiscaling, i.e. a fitness-dependent dynamic exponent, allowing fitter nodes to overcome the more connected but less fit ones. Uncovering this fitter-gets-richer phenomenon can help us understand in quantitative terms the evolution of many competitive systems in nature and society.

B. Blankertz, K. Müller, D. Krusienski et al.

Bo Becker, Todd Milbourn

Philip Valta

B. Fregly, T. Besier, D. Lloyd et al.

Margherita Gioria, B. Osborne

Invasions by alien plants provide a unique opportunity to examine competitive interactions among plants. While resource competition has long been regarded as a major mechanism responsible for successful invasions, given a well-known capacity for many invaders to become dominant and reduce plant diversity in the invaded communities, few studies have measured resource competition directly or have assessed its importance relative to that of other mechanisms, at different stages of an invasion process. Here, we review evidence comparing the competitive ability of invasive species vs. that of co-occurring native plants, along a range of environmental gradients, showing that many invasive species have a superior competitive ability over native species, although invasive congeners are not necessarily competitively superior over native congeners, nor are alien dominants are better competitors than native dominants. We discuss how the outcomes of competition depend on a number of factors, such as the heterogeneous distribution of resources, the stage of the invasion process, as well as phenotypic plasticity and evolutionary adaptation, which may result in increased or decreased competitive ability in both invasive and native species. Competitive advantages of invasive species over natives are often transient and only important at the early stages of an invasion process. It remains unclear how important resource competition is relative to other mechanisms (competition avoidance via phenological differences, niche differentiation in space associated with phylogenetic distance, recruitment and dispersal limitation, indirect competition, and allelopathy). Finally, we identify the conceptual and methodological issues characterizing competition studies in plant invasions, and we discuss future research needs, including examination of resource competition dynamics and the impact of global environmental change on competitive interactions between invasive and native species.

W. Wahyudi, O. Sukmana, B. Avianto

BACKGROUND AND OBJECTIVES: This research explores the impact of urbanization on informal workers in Surabaya, focusing on street vendors and day laborers. Urbanization in Surabaya has triggered significant economic and social transformations, created new job opportunities, and also increased challenges for informal workers.METHODS: The study employs a qualitative approach using in-depth interviews and participatory observation to collect data from informal workers.FINDINGS: The findings indicate that 78% of informal workers experience significant income volatility, while 65% report facing high competition and 72% lack access to essential resources. To cope, 68% extend their working hours, and 54% utilize social networks for support. Additionally, 61% of respondents benefit from government and non-profit support through training and economic empowerment programs, which has led to a 35% improvement in their skill levels. This study underscores the necessity for inclusive policies, as well as increased support for informal workers, to mitigate urbanization’s challenges and improve their overall quality of life.CONCLUSION: This research is expected to significantly contribute to understanding the dynamics of urbanization and its impact on informal workers, as well as offer practical solutions to improve their quality of life. Community support and optimized government policies can help address these challenges and create a more inclusive and sustainable urban environment.

Su Wang, Mengrui Pan, Yao Dong et al.

The WASP-47 system is notable as the first known system hosting both inner and outer low-mass planetary companions around a hot Jupiter, with an ultra-short-period (USP) planet as the innermost planetary companion. The formation of such a unique configuration poses challenges to the lonely hot Jupiter formation model. Hot Jupiters in multiple planetary systems may have a similar formation process with warm Jupiter systems, which are more commonly found with companions. This implies that the WASP-47 system could bridge our understanding of both hot and warm Jupiter formation. In this work, we propose a possible formation scenario for the WASP-47 system based on its orbital configuration. The mean motion resonance trapping, giant planet perturbations, and tidal effects caused by the central star are key factors in the formation of USP planets in multiple planetary systems with hot Jupiters. Whether a planet can become a USP planet or a short-period super-Earth planet depends on the competition between eccentricity excitation by nearby giant planet perturbations and the eccentricity damping due to tidal effects. The ${Q}_{p}^{{\prime} }$ value of the innermost planet is essential for the final planetary configuration. Our results suggest that a ${Q}_{p}^{{\prime} }$ in the range of [1, 10] is favorable for the formation of the WASP-47 system. Based on the formation scenario, we estimate an occurrence rate of 8.4% ± 2.4% for USP planets in systems similar to WASP-47.

McKinley D. Williams, Taylor R. Sweeney, Sabrina Trieu et al.

ABSTRACT Biofilms are an important colonization mechanism employed by several microbial species to better establish themselves and monopolize the acquisition of resources across different environs. Some bacteria have evolved specialized metabolites that, when secreted, disrupt the formation and stability of biofilms generated by competing heterospecies, providing the producing organism with an ecological advantage. Soil-derived species are probable candidates for the identification of such compounds, given the intense level of competition that occurs within the terrestrial ecosystem. The MS14 strain of Burkholderia contaminans isolated from soil in Mississippi has previously been shown to produce antimicrobial compounds like occidiofungin and ornibactin. In this report, we demonstrate that this strain also produces 4-hydroxy-3-methyl-2-alkenylquinoline (HMAQ-7), an alkaloid-based metabolite structurally similar to others produced by Burkholderia. HMAQ-7 was isolated and purified in sufficient quantities to enable the elucidation of its covalent structure and the evaluation of its biological effects. The compound was found to possess a unique ability to inhibit biofilm biosynthesis in several species, including opportunistic pathogens like Staphylococcus haemolyticus and within saliva-derived multispecies biofilms. HMAQ-7 also demonstrated an ability to modulate additional cellular behaviors in Bacillus subtilis, including motility and sporulation, suggesting that this molecule is important to the interspecies dynamics present across many diverse microenvironments.IMPORTANCEThe present study furthers our understanding of the structural complexity and the biological functions of the 2-alkyl-4(1H)-quinolone metabolites produced by Burkholderia spp. Low micromolar concentrations of HMAQ-7′ induced observable bacterial growth morphology differences. The antibiofilm properties of the HMAQ-7′ characterized in this study will promote future investigations into possible biological and applied roles. The ability to alter biofilm formation using HMAQ-7′ may facilitate Burkholderia spp. colonization in a multitude of environments, that is, aquatic, soil, and possibly during infection. HMAQ may subvert competition by potential competitor species in natural environments of Burkholderia spp. and possibly lung infections of cystic fibrosis patients.

Shadi Khalilolahi, Nasrin Kazemi, Saeid Besharati et al.

Background and purpose: The globalization of medical tourism has intensified competition among destinations, making it crucial to identify key success factors. While research emphasizes the role of host communities in tourism development, non-medical aspects of medical tourism remain underexplored. This study examines healthcare staff perspectives to identify the drivers and barriers affecting medical tourism in public hospitals. Methods: This qualitative study employed structured interviews with 16 healthcare staff at Masih Daneshvari Hospital, selected through purposive sampling. Interviews were conducted in person during the summer of 2024 until data saturation was reached. Data analysis followed an inductive content analysis approach using MAXQDA software for coding, grouping, and categorization of themes into drivers and barriers. Results: Key drivers of medical tourism development include skilled human resources, strong medical potential, affordable healthcare and associated costs, and the presence of complementary attractions. Conversely, major barriers include inadequate welfare services for medical tourists, managerial and institutional inefficiencies, hospital infrastructure deficiencies, and political and cultural challenges. Conclusion: Developing a successful medical tourism sector requires a holistic approach. Identifying, prioritizing, and implementing strategic plans to strengthen facilitators and address obstacles are essential steps toward sustainable growth in this field.