scholarly journals Imperfect strategy transmission can reverse the role of population viscosity on the evolution of altruism

2019 ◽  
Author(s):  
F. Débarre
Keyword(s):  
Life Cycle ◽  
Social Interactions ◽  
Side Effect ◽  
Life Cycles ◽  
Stochastic Simulations ◽  
Altruistic Behavior ◽  
Weak Selection ◽  
Related Individuals ◽  
Population Viscosity

AbstractPopulation viscosity, i.e., low emigration out of the natal deme, leads to high within-deme relatedness, which is beneficial to the evolution of altruistic behavior when social interactions take place among deme-mates. However, a detrimental side-effect of low emigration is the increase in competition among related individuals. The evolution of altruism depends on the balance between these opposite effects. This balance is already known to be affected by details of the life cycle; we show here that it further depends on the fidelity of strategy transmission from parents to their offspring. We consider different life cycles and identify thresholds of parent-offspring strategy transmission inaccuracy, above which higher emigration can increase the frequency of altruists maintained in the population. Predictions were first obtained analytically assuming weak selection and equal deme sizes, then confirmed with stochastic simulations relaxing these assumptions. Contrary to what happens with perfect strategy transmission from parent to off-spring, our results show that higher emigration can be favorable to the evolution of altruism.

scholarly journals Nuclear selection is effectively policed by mating restrictions of the dikaryotic life cycle of mushroom-forming fungi

2020 ◽  
Author(s):  
Ben Auxier ◽  
Tamas Czaran ◽  
Duur Aanen
Keyword(s):  
Life Cycle ◽  
Nuclear Envelope ◽  
Social Interactions ◽  
Haploid Nucleus ◽  
Fitness Consequences ◽  
Nuclear Selection ◽  
Related Individuals ◽  
Nuclear Exchange ◽  
Basidiomycete Fungi

AbstractAltruistic social interactions generally evolve between genetically related individuals or other replicators, whereas sexual interactions usually occur among unrelated individuals. This tension between social and sexual interactions is resolved by policing mechanisms enforcing cooperation among genetically unrelated entities. For example, most organisms with two haploid genomes are diploid, both genomes encapsulated inside a single nuclear envelope. A fascinating exception to this are Basidiomycete fungi, where the two haploid genomes remain separate. Uniquely, the haploid nuclei of the dikaryon can fertilize subsequent gametes encountered, the presumed benefit of this lifecycle. The implications for the balance of selection within and among individuals are largely unexplored. We modelled the implications of a fitness tradeoff at the level of the haploid nucleus versus the level of the fungal individual. We show that the most important policing mechanism is prohibition of fusion between dikaryons, which can otherwise select for detrimental levels of nuclear mating fitness. An additional policing mechanism revealed by our model is linkage between loci with fitness consequences. Our results show that benefits of di-mon matings must be paired with policing mechanisms to avoid uncontrolled selection at the level of the nuclei. Furthermore, we discuss evolutionary implications of recent claims of nuclear exchange in related fungal groups.

Exploring the role of business relationships in start-ups’ life cycles

IMP Journal ◽  
2018 ◽  
Vol 12 (3) ◽  
pp. 519-543
Author(s):  
Chiara Cantù ◽  
Sepe Giorgia ◽  
Alessandra Tzannis
Keyword(s):  
Life Cycle ◽  
Secondary Data ◽  
Life Cycles ◽  
Business Relationships ◽  
Structured Interviews ◽  
Content Type ◽  
Strategic Resources ◽  
Start Up ◽  
Start Ups

Purpose Differently from previous works that focused on the entrepreneur and on his ability to manage social relationships, the purpose of this paper is to investigate the role of business relationships in the different stages of the life cycle of a start-up. Design/methodology/approach Since the paper aims to explore startups’ evolutionary phenomenon, it adopts a qualitative abductive methodology, presenting an in-depth study of two innovative Italian start-ups. The research is based on two steps. In the first one, the authors collected secondary data from start-ups’ reports and documents, financial indicators (when available) and processed them to understand their background. In the second one, the authors conducted ten semi-structured interviews, including face-to-face interviews, phone interviews and video conferences. Findings The paper presents a relationship-based life cycle model composed of four different stages, depending on the number and role of relationships developed. Indeed, since the beginning, start-ups adopt a relational approach and their evolution involves the shift from the focus on the entrepreneur to the centrality of a network approach based on interconnected relationships. The entering into a new stage of life cycle depends on relationships, mainly based on connected actors and resources shared and combined. Even if a key role is assumed by technology, the main resource is identified in the knowledge concerning the customer/user’s needs that require marketing competencies, human resources, relational capabilities. Thus, the shift from one stage to the next in the start-up’s life cycle is possible thanks to a parallel shift from a focus on the activities to a focus on those strategic and heterogeneous actors that ensure activities. Originality/value In a traditional perspective, the start-up’s life cycle depends on activities, financial resources and revenues, as stated by previous life cycle models. In a different perspective, as depicted in our analysis, the evolution of a start-up depends on the portfolio of their business relationships. The role of business relationships is hence to facilitate the interconnections within specialized key actors, which allow start-ups to access strategic resources. These resources are essential in order to develop the activities that characterize the specific stage of the life cycle.

Tetractinomyxon stages genetically consistent withSphaerospora dicentrarchi(Myxozoa: Sphaerosporidae) found inCapitellasp. (Polychaeta: Capitellidae) suggest potential role of marine polychaetes in parasite's life cycle

Parasitology ◽  
2016 ◽  
Vol 143 (8) ◽  
pp. 1067-1073 ◽  
Author(s):  
LUIS F. RANGEL ◽  
RICARDO CASTRO ◽  
SÓNIA ROCHA ◽  
RICARDO SEVERINO ◽  
GRAÇA CASAL ◽  
...  
Keyword(s):  
Life Cycle ◽  
Dna Sequences ◽  
Dicentrarchus Labrax ◽  
18S Rrna Gene ◽  
Life Cycles ◽  
Fish Farm ◽  
Rrna Gene ◽  
Commercial Fish ◽  
European Seabass

SUMMARYKnown life cycles of myxosporean parasites have two hosts, but very few life cycles have been disclosed, especially in the marine environment.Sphaerospora dicentrarchiSitjà-Bobadilla and Álvarez-Pellitero, 1992 is a systemic parasite from the European seabass,Dicentrarchus labrax(Linnaeus, 1758), a highly valuable commercial fish. It affects its health, leading to aquaculture production losses. During 2013 and 2014, an actinospore survey was conducted in a total of 5942 annelids collected from a fish farm in Algarve and from the Aveiro Estuary, in Portugal. A new tetractinomyxon actinospore was found in a capitellid polychaete, belonging to the generaCapitellacollected at the fish farm. The tetractinomyxons were pyriform measuring 11·1 ± 0·7µm in length and 7·2 ± 0·4µm in width, and presented three rounded polar capsules measuring 2·4 ± 0·3µm in diameter. The molecular analysis of the 18S rRNA gene sequences from the tetractinomyxons revealed a similarity of 100% with the DNA sequences deposited in the GenBank fromS. dicentrarchimyxospores collected from the European seabass and the spotted seabass in the same fish farm and 99·9% similarity with the DNA sequence obtained from the myxospores found infecting the European seabass in the Aveiro Estuary. Therefore, the new tetractinomyxons are inferred to represent the actinospore phase of theS. dicentrarchilife cycle.

scholarly journals ICTIOFAUNA DE POÇAS DE MARÉ EM TERRAÇOS CONSOLIDADOS DO LITORAL AMAZÔNICO BRASILEIRO

2021 ◽  
Vol 25 (04) ◽  
pp. 880-888
Author(s):  
Rayane Gonçalves Aguiar ◽  
◽  
Erick Cristofore Guimarães ◽  
Pâmella Silva de Brito ◽  
Felipe Polivanov Ottoni ◽  
...  
Keyword(s):  
Life Cycle ◽  
Brazilian Amazon ◽  
Life Cycles ◽  
Main Role ◽  
Physiological Plasticity ◽  
Biodiversity Knowledge ◽  
Tidal Pools ◽  
Species Being ◽  
Intertidal Fishes

As poças de maré são formadas pelo represamento de massas d’água durante a vazante e a sua troca ocorre ao longo de cada ciclo de marés, configurando em um ambiente explorado por várias espécies. A ictiofauna é um componente das poças de maré, algumas espécies são totalmente adaptadas (e.g. plasticidade fisológica, tamanho reduzido) e seu ciclo de vida ocorre apenas nas poças de maré. Contudo, muitas espécies utilizam as poças de maré em algumas fases do ciclo de vida para fins de alimentação, refúgio e reprodução. Considerando que os inventários são fundamentais para o conhecimento da biodiversidade, nosso estudo investigou a assembleia de peixes em poças de marés da Praia do Araçagy no período de outubro de 2016 a abril de 2017. No total, nós registramos 409 exemplares, pertencendo a 13 espécies, distribuídas em 11 famílias e sete ordens. Espécies residentes e estuarinas de importância comercial foram dominantes. INTERTIDAL FISHES OF THE CEMENTED TERRACES FROM BRAZILIAN AMAZON COAST: Tidal pools are formed by the damming of marine water during an ebb tide and their exchange occurs along each tidal cycle, configuring an environment explored by several species. The ichthyofauna is one of the components of the tide pools, with some species being fully adapted (e. g. physiological plasticity, reduced size) and their life cycles occuring uniquely on this environment. However, most species use tide pools at some stage of their life cycle for feeding, refuge and reproduction. Considering the main role of faunal inventories for the increase in biodiversity knowledge, this study investigates the fish assemblage in tide pools at Praia do Araçagy from October 2016 to April 2017. In total, were recorded 409 specimens belonging to 13 species, distributed in 11 families and seven orders. Resident and estuarine species with commercial importance were dominant.

The role of cloud diabatic processes in the life cycle of Atlantic-European weather regimes

2021 ◽  
Author(s):  
Christian M. Grams
Keyword(s):  
Life Cycle ◽  
Large Scale ◽  
Multiple Scales ◽  
Weather Prediction ◽  
Time Lag ◽  
Conveyor Belt ◽  
Life Cycles ◽  
Weather Regimes ◽  
Diabatic Processes

<p>Weather regimes are quasi-stationary, persistent, and recurrent states of the large-scale extratropical circulation. In the Atlantic-European region these explain most of the atmospheric variability on sub-seasonal time scales. However, current numerical weather prediction (NWP) systems struggle in correctly predicting weather regime life cycles. Latent heat release in ascending air streams injects air into the upper troposphere, which might ultimately result in blocking. Such diabatic outflow is often linked to warm conveyor belt (WCB) activity and has been shown to be involved in upscale error growth up to the regime scale. This study systematically investigates the role of diabatic outflow in the life cycle of Atlantic-European weather regimes.</p><p>An extended definition of 7 year-round Atlantic-European weather regimes from 37 years of ERA-Interim reanalysis is used. This is based on an EOF analysis and k-means clustering of normalized low-pass-filtered 500hPa geopotential height anomalies. Furthermore an objective regime life cycle is derived. The role of cloud-diabatic processes in European weather regimes is assessed based on time lag analysis of WCB activity at specific life cycle stages.</p><p>Results indicate that the period prior to regime onset is characterized by important changes in location and frequency of WCB occurrence. Most importantly, prior to the onset of regimes characterized by blocking, WCB activity increases significantly upstream of the incipient blocking even before blocking is detectable and persists over the blocked region later. This suggests that diabatic WCB outflow helps to establish and maintain blocked regimes. Thus it is important to correctly represent cloud-diabatic processes in NWP models across multiple scales in order to predict the large-scale circulation accurately. Ongoing work now systematically investigates the representation of WCB activity in current NWP systems and how this relates to the forecast skill for weather regimes.</p>

scholarly journals Understanding the Life Cycles of Entrepreneurial Teams and Their Ventures: An Agenda for Future Research

2020 ◽  
pp. 104225872097838
Author(s):  
Holger Patzelt ◽  
Rebecca Preller ◽  
Nicola Breugst
Keyword(s):  
Life Cycle ◽  
Life Cycles ◽  
Team Formation ◽  
Future Research ◽  
Entrepreneurial Teams ◽  
The Past ◽  
Entrepreneurial Team ◽  
Over Time

While research on entrepreneurial teams has flourished over the past two decades, it has mainly taken a static perspective, neglecting the developments both teams and their ventures undergo over time. To address this issue, we develop a “double life cycle framework” covering entrepreneurial teams’ formation, collaboration, and dissolution phases as well as potential nonlinear sequences of these phases. While this team life cycle is embedded in the venture life cycle, both life cycles can progress independently. We offer research suggestions on entrepreneurial team formation, collaboration, and dissolution in each venture phase, highlighting the role of entrepreneurial teams in advancing their ventures.

scholarly journals Inferring forest fate from demographic data: from vital rates to population dynamic models

2018 ◽  
Vol 285 (1874) ◽  
pp. 20172050 ◽  
Author(s):  
Jessica Needham ◽  
Cory Merow ◽  
Chia-Hao Chang-Yang ◽  
Hal Caswell ◽  
Sean M. McMahon
Keyword(s):  
Population Dynamics ◽  
Life Cycle ◽  
Dynamic Models ◽  
Demographic Data ◽  
Life Cycles ◽  
Stochastic Simulations ◽  
Life History Strategies ◽  
Forest Trees ◽  
Vital Rates ◽  
Passage Times

As population-level patterns of interest in forests emerge from individual vital rates, modelling forest dynamics requires making the link between the scales at which data are collected (individual stems) and the scales at which questions are asked (e.g. populations and communities). Structured population models (e.g. integral projection models (IPMs)) are useful tools for linking vital rates to population dynamics. However, the application of such models to forest trees remains challenging owing to features of tree life cycles, such as slow growth, long lifespan and lack of data on crucial ontogenic stages. We developed a survival model that accounts for size-dependent mortality and a growth model that characterizes individual heterogeneity. We integrated vital rate models into two types of population model; an analytically tractable form of IPM and an individual-based model (IBM) that is applied with stochastic simulations. We calculated longevities, passage times to, and occupancy time in, different life cycle stages, important metrics for understanding how demographic rates translate into patterns of forest turnover and carbon residence times. Here, we illustrate the methods for three tropical forest species with varying life-forms. Population dynamics from IPMs and IBMs matched a 34 year time series of data (albeit a snapshot of the life cycle for canopy trees) and highlight differences in life-history strategies between species. Specifically, the greater variation in growth rates within the two canopy species suggests an ability to respond to available resources, which in turn manifests as faster passage times and greater occupancy times in larger size classes. The framework presented here offers a novel and accessible approach to modelling the population dynamics of forest trees.

Managing Organizations

2013 ◽  
pp. 1-15
Keyword(s):  
Life Cycle ◽  
Organizational Behavior ◽  
Customer Orientation ◽  
Life Cycles ◽  
Organizational Life ◽  
Process Technology ◽  
Organizational Continuity ◽  
Evolutionary Phase ◽  
Culture Strategies

Managing organizations has always remained a challenge for its stakeholders. Challenges are not restricted only to managing factors of production like human resources, capital, and materials in the supply chain, but they also include important determinants for having a better culture, strategies for market and customer orientation, product innovations, and others. Life cycles in organizations are generally influenced by its products and services they deliver because they are to be accepted by the market, processes they adopt to meet the market-oriented product and services, and structures because of corrective measures adopted during every evolutionary phase organizations go through. Because of these effects in an organizational life cycle, organizations need to look after the systemic behaviors in order to ensure that continuity in the systems is retained. In order to achieve these objectives, there is need for the organization to remain prepared to seamlessly integrate organizational behavior with that of process, technology, and people. This chapter discusses these dimensions related to management of organizations, including motivation for creation of organizations, the desire to exist in the market with a better life cycle, and the role of management to ensure organizational continuity.

Value-driven issues throughout the development of sociological theory

2020 ◽  
pp. 147-160
Author(s):  
Gulbarshyn Chepurko ◽  
Valerii Pylypenko
Keyword(s):  
Social Interactions ◽  
Social System ◽  
Sociological Theory ◽  
Social Scientists ◽  
Social Sphere ◽  
Technological Advances ◽  
The Social ◽  
The Individual ◽  
Different Levels

The paper examines and compares how the major sociological theories treat axiological issues. Value-driven topics are analysed in view of their relevance to society in times of crisis, when both societal life and the very structure of society undergo dramatic change. Nowadays, social scientists around the world are also witnessing such a change due to the emergence of alternative schools of sociological thought (non-classical, interpretive, postmodern, etc.) and, subsequently, the necessity to revise the paradigms that have been existed in sociology so far. Since the above-mentioned approaches are often used to address value-related issues, building a solid theoretical framework for these studies takes on considerable significance. Furthermore, the paradigm revision has been prompted by technological advances changing all areas of people’s lives, especially social interactions. The global human community, integral in nature, is being formed, and production of human values now matters more than production of things; hence the “expansion” of value-focused perspectives in contemporary sociology. The authors give special attention to collectivities which are higher-order units of the social system. These units are described as well-organised action systems where each individual performs his/her specific role. Just as the role of an individual is distinct from that of the collectivity (because the individual and the collectivity are different as units), so too a distinction is drawn between the value and the norm — because they represent different levels of social relationships. Values are the main connecting element between the society’s cultural system and the social sphere while norms, for the most part, belong to the social system. Values serve primarily to maintain the pattern according to which the society is functioning at a given time; norms are essential to social integration. Apart from being the means of regulating social processes and relationships, norms embody the “principles” that can be applied beyond a particular social system. The authors underline that it is important for Ukrainian sociology to keep abreast of the latest developments in the field of axiology and make good use of those ideas because this is a prerequisite for its successful integration into the global sociological community.

Sign in / Sign up

Export Citation Format

Share Document