Experimental results on the roommate problem

We use laboratory experiments to analyze decentralized decision-making in one-sided matching markets. We find that subjects tend to make decisions in line with theoretical models, as their offering and accepting decisions are only guided by the objective of improving upon the status quo. However, isolated individual mistakes, that do not disappear with experience or time, often make theoretically-stable matchings unstable in the laboratory. Markets with incomplete infor- mation are especially prone to this problem.convergence, experiments, one-sided matching, stability

Exchange of indivisible goods and indifferences: the Top Trading Absorbing Sets mechanisms

There is a wide range of economic problems involving the exchange of indivisible goods without monetary transfers, starting from the housing market model of the seminal paper of Shapley and Scarf [10] and including other problems like the kidney exchange or the school choice problems. For many of these models, the classical solution is the application of an algorithm/mechanism called Top Trading Cycles, attributed to David Gale, which satisfies good properties for the case of strict preferences. In this paper, we propose a family of mechanisms, called Top Trading Absorbing Sets mechanisms, that generalizes the Top Trading Cycles for the general case in which individuals can report indifferences, and preserves all its desirable properties.housing market, indifferences, top trading cycles, absorbing sets

The stability of the roommate problem revisited

The lack of stability in some matching problems suggests that alternative solution concepts to the core might be a step towards furthering our understanding of matching market performance. We propose absorbing sets as a solution for the class of roommate problems with strict preferences. This solution, which always exists, either gives the matchings in the core or predicts other matchings when the core is empty. Furthermore, it satisfies the interesting property of outer stability. We also determine the matchings in absorbing sets and find that in the case of multiple absorbing sets a similar structure is shared by all.roommate problem, core, absorbing sets

Time Series Analysis of Major League Baseball Organizations’ Fan Attendance

Throughout baseball’s rich and long history, fans have been one of the most integral parts of the game. However, in recent years, baseball has seen a decrease in fans, allegedly due to the pace of play, or the length of games. Baseball games can take up to four hours to complete, and in today’s fast-moving society where all information is at one’s fingertips, it is believed that baseball’s slower pace turns people away from the game. However, how true is that? The primary goal of this project is to build models to accurately forecast fan attendance for every Major League Baseball (MLB) team. With teams across the country with varying levels of success, can fan attendance be accurately predicted using time series analysis using fan attendance data from the 1988 to 2019 season. This range allows us to analyze 32 years of data for total fan attendance per season for all thirty teams. The 2020 and 2021 seasons were not used as fans were not allowed in stadiums during these years due to COVID-19. After creating time series models using the data, forecasts were made for the 2022 and 2023 seasons to determine the accuracy of the models

Shallow water assemblages exposed to abiotic disturbance & stress: the structuring role of emersion and UV-radiation

Using field experiments, I tested the applicability of the “Intermediate Disturbance Hypothesis” (IDH). Diversity H` showed a unimodal response for both disturbance qualities, evenness and species richness only along the emersion and enhanced UVB gradient, respectively. However, response patterns along disturbance gradients were inconsistent and the unimodal pattern non-persistent. By extending Connell´s IDH model, I conclude that a reduction in diversity of emersion treatments under harsh conditions results from a shift in dominance, to species well adapted for that disturbance quality, rather than loss of species. Enhanced UVB radiation generated a unimodal response for diversity at a time when emersion did not, suggesting different mechanisms between both disturbance qualities in producing the same pattern. The role of the green alga Enteromorpha intestinalis was discussed in that respect. Effects of ambient UV stress were non-persistent, both at the SE Atlantic and Baltic Sea study site. UVA radiation alone was without effect on fouling assemblage structure at both sites. Already ambient UV radiation lowered diversity H` and species richness, but not evenness, at the SE Atlantic site, while enhanced UVB reduced diversity H`, species richness and evenness at the Baltic Sea site. The role of protective shading under the canopy of UV-resistant algae (Enteromorpha intestinalis at the Baltic Sea site and Ceramium sp. at the SE Atlantic site) for the generation of non-persistent effects was discussed in that context. Inter-active effects between UV radiation and consumers were almost absent at both study sites and in addition, non-persistent for the rare occasions when they occurred. In conclusion, my results suggest the applicability of the IDH, but the unimodal response for diversity was (i) modified by inter-annual variability in recruitment and growth of dominant species, (ii) non-persistent in succession, (iii) dependent on the chosen disturbance quality and (iv) diversity parameter. A non-persistent ecological relevance of UV stress was shown for two distinct fouling assemblages, grown under different natural irradiance regimes

Baltarusijos faktinio suvereniteto vertinimas Rusijos įtakos kontekste

The paper explores state sovereignty by developing a systematic framework for categorising states based on their sovereignty status. At the heart of our analysis lies the distinction between sovereign states and satellite states – a distinction that has significant implications for global security, stability, and the balance of power. While sovereign states exercise full autonomy and control over their affairs, satellite states often find themselves in a subordinate position, heavily influenced or even dominated by external powers. A theoretical framework deconstructs the concept of sovereignty into four crucial elements: authority, legitimacy, independence, and territoriality, which provide a structured assessment of the level of sovereignty in a state and serve as the basis for our analysis. To illustrate the application of our framework, we adopt a case study approach focused on Belarus. As a nation situated at the crossroads of Eastern Europe with a history marked by geopolitical contestation and strategic manoeuvring, Belarus provides a compelling context for examining sovereignty dynamics. Through a systematic analysis of Belarus’ political, economic, and military landscape, we seek to assess its sovereignty status within the framework of our analysis. While the topic of Belarus’ sovereignty and integration within Russia has been extensively explored over the years, the innovative contribution of this paper lies in purposefully designed methodology for sovereignty assessment and the use of the latest empirical data while practically applying the model for the case of Belarus.Straipsnyje nagrinėjami valstybių suvereniteto kausimai, siekiant sukurti sisteminį pagrindą tolesniam ir kitų valstybių skirstymui pagal jų suvereniteto lygį. Tyrimo tikslas – nubrėžti aiškią takoskyrą tarp suverenių, pusiau suverenių ir satelitinių valstybių. Tyrimo svarbą lemia ta aplinkybė, jog skirtingas suvereniteto lygmuo gali turėti didelę reikšmę pasauliniam saugumui, stabilumui ir galios pusiausvyrai tarptautinėje sistemoje. Šiame kontekste suvereniomis valstybėmis tyrime įvardijamos visiškai savarankiškos ir kontroliuojančios savo politinius sprendimus šalys, o satelitinėmis – tos, kurios de facto patiria didelę išorės jėgų įtaką. Teorinėje tyrimo dalyje suvereniteto sąvoka išskaidoma į keturis esminius struktūrinius elementus: valstybės valdymą, teisėtumą, nepriklausomybę ir teritorinį vientisumą. Siekiant iliustruoti ir patikrinti kuriamos suvereniteto vertinimo sistemos taikymo efektyvumą yra nagrinėjamas Baltarusijos atvejis. Baltarusija, kaip Rytų Europos kryžkelėje esanti valstybė, kurios istorija nusižymėta geopolitinėmis varžytuvėmis, yra tinkamas pavyzdys suvereniteto dinamikai nagrinėti. Sistemingai analizuojant Baltarusijos politinį, ekonominį ir karinį kontekstą, tyrime nuosekliai vertinamas šalies suvereniteto status quo. Nors Baltarusijos suvereniteto ir integracijos į Rusiją tema jau daugelį metų yra plačiai nagrinėjama, darbo naujumą lemia kuriama suvereniteto vertinimo metodika ir naujausių empirinių duomenų panaudojimas praktiškai taikant modelį Baltarusijos atvejo analizei

Transient effects of solar ultraviolet radiation on the diversity and structure of a field-grown epibenthic community at Lüderitz, Namibia

While the majority of research on ultraviolet radiation (UVR) has focused on UVR-induced changes in the productivity and abundance of single taxonomic groups, only a few field studies have considered the influence of ambient UVR on complete assemblages, in particular of the macrobenthos. Using cutoff filters, we followed the effects of three radiation treatments, (1) PAR+UVAR+UVBR, (2) PAR+UVAR, (3) PAR, on macrobenthic community structure at Luderitz, Namibia, SE Atlantic, for 3 months. Species composition, biomass, evenness, and species richness were not significantly affected by UVR. while the diversity IT of PAR+UVAR+UVBR-exposed communities was significantly lower compared to PAR treatments. However, this effect was only observed early in succession. Increased abundance of the red alga Ceramium sp. coincided with vanishing UVR effects on the community, suggesting a muted UVR microclimate under the Ceramium canopy. Our results demonstrate that UVR could neither decrease diversity persistently, nor affect any of the other tested community parameters. Single UVR-tolerant species may provide protective shading for UVR-sensitive species, thus buffering harmful UVR effects at the community level. Missing UVBR effects suggest a limited influence of ozone depletion on shallow water macrobenthic diversity. (C) 2003 Elsevier B.V. All rights reserved