31 research outputs found
Retrograde traffic in the biosynthetic-secretory route
In the biosynthetic-secretory route from the rough endoplasmic reticulum, across the pre-Golgi intermediate compartments, the Golgi apparatus stacks, trans Golgi network, and post-Golgi organelles, anterograde transport is accompanied and counterbalanced by retrograde traffic of both membranes and contents. In the physiologic dynamics of cells, retrograde flow is necessary for retrieval of molecules that escaped from their compartments of function, for keeping the compartmentsâ balances, and maintenance of the functional integrities of organelles and compartments along the secretory route, for repeated use of molecules, and molecule repair. Internalized molecules may be transported in retrograde direction along certain sections of the secretory route, and compartments and machineries of the secretory pathway may be misused by toxins. An important example is the toxin of Shigella dysenteriae, which has been shown to travel from the cell surface across endosomes, and the Golgi apparatus en route to the endoplasmic reticulum, and the cytosol, where it exerts its deleterious effects. Most importantly in medical research, knowledge about the retrograde cellular pathways is increasingly being utilized for the development of strategies for targeted delivery of drugs to the interior of cells. Multiple details about the molecular transport machineries involved in retrograde traffic are known; a high number of the molecular constituents have been characterized, and the complicated fine structural architectures of the compartments involved become more and more visible. However, multiple contradictions exist, and already established traffic models again are in question by contradictory results obtained with diverse cell systems, and/or different techniques. Additional problems arise by the fact that the conditions used in the experimental protocols frequently do not reflect the physiologic situations of the cells. Regular and pathologic situations often are intermingled, and experimental treatments by themselves change cell organizations. This review addresses physiologic and pathologic situations, tries to correlate results obtained by different cell biologic techniques, and asks questions, which may be the basis and starting point for further investigations
The Nachtlichter app: a citizen science tool for documenting outdoor light sources in public space
The relationship between satellite based measurements of city radiance at night and the numbers and types of physical lights installed on the ground is not well understood. Here we present the "Nachtlichter app", which was developed to enable citizen scientists to classify and count light sources along street segments over large spatial scales. The project and app were co-designed: citizen scientists played key roles in the app development, testing, and recruitment, as well as in analysis of the data. In addition to describing the app itself and the data format, we provide a general overview of the project, including training materials, data cleaning, and the result of some basic data consistency checks
Monetary Circuit Theory and the Role of Banks in the Monetization of Profits
Using the tools of the monetary circuit the paradox of profits on how the firm sector as a whole can realize profits is addressed. The thesis innovates with the banking system facing the same profit paradox as firms and how it can be overcome. Observing the microeconomics of the monetary circuit and introducing overlapping circuits of different lengths the paradox of profits is solved. It is the banking systemsâ role in providing accommodative credit putting new money into circulation that allows profits to be realized. After a firm takes a loan the newly created money flows through other firms creating profits on the way, therefore an emphasis on the velocity of money is taken. Other studies emphasizing the velocity are therefore confirmed. The aggregation of different types of microeconomic monetary flows results in the national accounts as an ex post notion. The result is that the components of the national accounts should not be interpreted as restricting each other, they rather move in line. It is found that stock-flow consistent modelling provides a sound basis for displaying the banking systemsâ role in enabling profits
The V-Dem Measurement Model: Latent Variable Analysis for Cross-National and Cross-Temporal Expert-Coded Data
The Varieties of Democracy (V-Dem) project relies on country experts who code a host of ordinal variables, providing subjective ratings of latent- that is, not directly observable- regime characteristics over time. Sets of around five experts rate each case (country-year observation), and each of these raters works independently. Since raters may diverge in their coding because of either differences of opinion or mistakes, we require systematic tools with which to model these patterns of disagreement. These tools allow us to aggregate ratings into point estimates of latent concepts and quantify our uncertainty around these point estimates. In this paper we describe item response theory models that can that account and adjust for differential item functioning (i.e. differences in how experts apply ordinal scales to cases) and variation in rater reliability (i.e. random error). We also discuss key challenges specific to applying item response theory to expert-coded cross-national panel data, explain the approaches that we use to address these challenges, highlight potential problems with our current framework, and describe long-term plans for improving our models and estimates. Finally, we provide an overview of the different forms in which we present model output.This material is based upon work supported by the National Science Foundation (SES-1423944, PI: Daniel Pemstein), Riksbankens Jubileumsfond (Grant M13-0559:1, PI: Staffan I. Lindberg), the Swedish Research Council (2013.0166, PI: Staffan I. Lindberg and Jan Teorell), the Knut and Alice Wallenberg Foundation (PI: Staffan I. Lindberg), and the University of Gothenburg (E 2013/43); as well as internal grants from the Vice-Chancellorâs office, the Dean of the College of Social Sciences, and the Department of Political Science at University of Gothenburg. Marquardt acknowledges research support from the Russian Academic Excellence Project â5-100.â We performed simulations and other computational tasks using resources provided by the Notre Dame Center for Research Computing (CRC) through the High Performance Computing section and the Swedish National Infrastructure for Computing (SNIC) at the National Supercomputer Centre in Sweden (SNIC 2016/1-382, SNIC 2017/1-406 and 2017/1-68). We specifically acknowledge the assistance of In-Saeng Suh at CRC and Johan Raber and Peter Mu Ìnger at SNIC in facilitating our use of their respective systems