56 research outputs found
Tomemos en serio la evolución: Análisis institucional y teoría evolutiva.
En este ensayo exploramos los supuestos epistemológicos y ontológicos que se adoptaron para que la ciencia política fuera “científica”. Mostramos que adoptó en general una filosofía ontológicamente reduccionista de la ciencia derivada de la física newtoniana. Este marco mecánico tiene problemas y restricciones en su poder explicativo porque el énfasis en el análisis del equilibrio es inadecuado para el estudio del cambio político. Describimos las principales diferencias entre una ontología evolucionista de la ciencia social y la filosofía basada en la física que se suele utilizar. Por último, mostramos que el pensamiento evolutivo mejora la comprensión de fenómenos políticos y preguntas de investigación que son de importancia central en este campo, como la formación de preferencias.cambio institucional endógeno, teoría evolutiva, sistemas adaptativos complejos, nuevo institucionalismo.
Hem-1 Complexes Are Essential for Rac Activation, Actin Polymerization, and Myosin Regulation during Neutrophil Chemotaxis
Migrating cells need to make different actin assemblies at the cell's leading and trailing edges and to maintain physical separation of signals for these assemblies. This asymmetric control of activities represents one important form of cell polarity. There are significant gaps in our understanding of the components involved in generating and maintaining polarity during chemotaxis. Here we characterize a family of complexes (which we term leading edge complexes), scaffolded by hematopoietic protein 1 (Hem-1), that organize the neutrophil's leading edge. The Wiskott-Aldrich syndrome protein family Verprolin-homologous protein (WAVE)2 complex, which mediates activation of actin polymerization by Rac, is only one member of this family. A subset of these leading edge complexes are biochemically separable from the WAVE2 complex and contain a diverse set of potential polarity-regulating proteins. RNA interference–mediated knockdown of Hem-1–containing complexes in neutrophil-like cells: (a) dramatically impairs attractant-induced actin polymerization, polarity, and chemotaxis; (b) substantially weakens Rac activation and phosphatidylinositol-(3,4,5)-tris-phosphate production, disrupting the (phosphatidylinositol-(3,4,5)-tris-phosphate)/Rac/F-actin–mediated feedback circuit that organizes the leading edge; and (c) prevents exclusion of activated myosin from the leading edge, perhaps by misregulating leading edge complexes that contain inhibitors of the Rho-actomyosin pathway. Taken together, these observations show that versatile Hem-1–containing complexes coordinate diverse regulatory signals at the leading edge of polarized neutrophils, including but not confined to those involving WAVE2-dependent actin polymerization
The Science Performance of JWST as Characterized in Commissioning
This paper characterizes the actual science performance of the James Webb
Space Telescope (JWST), as determined from the six month commissioning period.
We summarize the performance of the spacecraft, telescope, science instruments,
and ground system, with an emphasis on differences from pre-launch
expectations. Commissioning has made clear that JWST is fully capable of
achieving the discoveries for which it was built. Moreover, almost across the
board, the science performance of JWST is better than expected; in most cases,
JWST will go deeper faster than expected. The telescope and instrument suite
have demonstrated the sensitivity, stability, image quality, and spectral range
that are necessary to transform our understanding of the cosmos through
observations spanning from near-earth asteroids to the most distant galaxies.Comment: 5th version as accepted to PASP; 31 pages, 18 figures;
https://iopscience.iop.org/article/10.1088/1538-3873/acb29
The James Webb Space Telescope Mission
Twenty-six years ago a small committee report, building on earlier studies,
expounded a compelling and poetic vision for the future of astronomy, calling
for an infrared-optimized space telescope with an aperture of at least .
With the support of their governments in the US, Europe, and Canada, 20,000
people realized that vision as the James Webb Space Telescope. A
generation of astronomers will celebrate their accomplishments for the life of
the mission, potentially as long as 20 years, and beyond. This report and the
scientific discoveries that follow are extended thank-you notes to the 20,000
team members. The telescope is working perfectly, with much better image
quality than expected. In this and accompanying papers, we give a brief
history, describe the observatory, outline its objectives and current observing
program, and discuss the inventions and people who made it possible. We cite
detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space
Telescope Overview, 29 pages, 4 figure
How Institutions Evolve: Evolutionary theory and institutional change
This paper is also the product of the insightful contributions of numerous participants in the workshop “Do Institutions Evolve?” held in May 2009 at the Robert Schuman Centre at the European University Institute.External link is for Polity Podcast: Interview with the author on the articleThis article argues that questions of gradual institutional change can be understood as an evolutionary process that can be explained through the careful application of “generalized Darwinism.” We argue that humans' advanced cognitive capacities contribute to an evolutionary understanding of institutional change. In constantly generating new variation upon which mechanisms of selection and replication operate, cognition, cognitive schemas, and ideas become central for understanding the building of human institutions, as well as the scope and pace of their evolution. Evolutionary theories thus provide a broad theoretical framework that integrates the study of cognition, ideas, and decision-making with other literatures that focus on institutional change and human evolution
Methodological Appendix: Authoritarian Evolution
Detailed methodological appendix for the article authoritarian evolution: Agency and Institutional Change in a Controlled Chinese Press
Globalization, Domestic Stability and Freedom of the Press
<p>This paper empirically models the determinants of “press freedom,” which is an important, if under-studied, institution of good governance. A free press plays a vital economic role in aggregating information, facilitating coordination, reducing transaction costs, increasing transparency, and holding economic and political elites accountable. Therefore actors who believe in sound economic governance should support the creation of an independent press, while those that seek to obscure bad information should oppose it. Drawing on the literature on the nexus of economic globalization and democracy, this study explains economic globalization’s impact on states’ calculations regarding press freedom. Economic globalization is modeled not as a single unified process, but rather as a disaggregated interrelated set of economic and political processes. Using panel data from the period 1993-2006, it finds empirical support for the significant influence of investment ratings, “market–seeking” foreign direct investment, and international aid in promoting press freedom. However these positive influences are countered by with the negative effects of trade liberalization, “efficiency-seeking” FDI, and social instability. Thus economic globalization generates contradictory pressures with respect to press freedom. This is because only certain types of international investment have an interest in greater transparency, while other processes such as trade liberalization can lead to a social backlash and instability, indirectly undermining globalizations positive influences. These results are robust with respect to different estimation techniques and alternative specifications.</p
Taking Evolution Seriously in Political Science
In this essay, we explore the epistemological and ontological assumptions that have been made to make political science scientific. We show how political science has generally adopted an ontologically reductionist philosophy of science derived from Newtonian physics and mechanics. This mechanical framework has encountered problems and constraints on its explanatory power, because an emphasis on equilibrium analysis is ill-suited for the study of political change. We outline the primary differences between an evolutionary ontology of social science and the physics-based philosophy commonly employed. Finally, we show how evolutionary thinking adds insight into the study of political phenomena and research questions that are of central importance to the field, such as preference formation
Taking Evolution Seriously: Institutional analysis and evolutionary theory
En este ensayo exploramos los supuestos epistemológicos y ontológicos que se adoptaron para que la ciencia política fuera “científica”. Mostramos que adoptó en general una filosofía ontológicamente reduccionista de la ciencia derivada de la física newtoniana. Este marco mecánico tiene problemas y restricciones en su poder explicativo porque el énfasis en el análisis del equilibrio es inadecuado para el estudio del cambio político. Describimos las principales diferencias entre una ontología evolucionista de la ciencia social y la filosofía basada en la física que se suele utilizar. Por último, mostramos que el pensamiento evolutivo mejora la comprensión de fenómenos políticos y preguntas de investigación que son de importancia central en este campo, como la formación de preferencias
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