Resolving a Replication That Failed: News on the Macy & Sato Model

The paper at hand aimes at identifying the assumptions that lead to the results presented in an article by Michael Macy and Yoshimichi Sato published in PNAS. In answer to a failed replication, the authors provided the source code of their model and here the results of carefully studying that code are presented. The main finding is that the simulation program implements an assumption that is most probably an unwilling, unintended, and unwanted implication of the code. This implied assumption is never mentioned in Macy and Sato's article and if the authors wanted to program what they describe in their article then it is due to a programming error. After introducing the reader to the discussion, data that stem from a new replication based on the assumptions extracted from the source code is compared with the results published in Macy and Sato's original article. The replicated results are sufficiently similar to serve as a strong indicator that this new replication implements the same relevant assumptions as the original model. Afterwards it is shown that a removal of the dubious assumption leads to results that are dramatically different from those published in Macy and Sato's PNAS article.Replication, Social Dilemma Situations, Trust, Simulation Methodology, Cooperation

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Cavalry Charge

The black and white engraving depicts a scene from a Civil War battle. Several men ride on horseback with swords drawn. Some are shown falling from their horses or lifeless on the ground. Dust fills the scene in the background. The image is printed on off-white paper with black ink. It appears to have been removed from a bound volume.https://scholarsjunction.msstate.edu/fvw-prints/1079/thumbnail.jp

Charge on the Battery

The black and white engraving depicts a battle scene. Soldiers armed with rifles charge a cloudy/smoky battlefield. The image is printed on off-white paper with black ink and appears to have been removed from a bound volume.https://scholarsjunction.msstate.edu/fvw-artifacts/1160/thumbnail.jp

Charge on the Battery

The black and white engraving depicts a battle scene. Soldiers armed with rifles charge a cloudy/smoky battlefield. The image is printed on off-white paper with black ink and appears to have been removed from a bound volume.https://scholarsjunction.msstate.edu/fvw-prints/1083/thumbnail.jp

Educational policies matter. How schooling strategies influence refugee adolescents\u27 school participation in lower secondary education in Germany

This article investigates the educational participation of refugee adolescents in Germany. Opportunities and restrictions for school participation vary not only across countries–, but in the case of the Federal Republic of Germany, also within countries. The influence of different regional educational policies on refugees\u27 educational participation and the extent to which they limit or enable individual agency, are however, widely understudied. We aim to analyze how different regional educational policies within Germany influence refugee students\u27 educational participation regarding four central indicators: the duration until school enrollment, the type of class attended (newcomer vs. regular class), the type of school attended, and whether they are enrolled in settings appropriate for their age. We rely on a theoretical model which sees educational decisions as the result of rational cost-benefit calculations. Our analyses are based on data from 2,415 adolescents who were interviewed in the “ReGES–Refugees in the German Educational System” study. Our results show significant correlations between different regional educational policies and the four domains of educational participation. These effects remain stable when considering family and individual resources, as well as further control variables that previous research on social and ethnic educational inequality has shown to be relevant. Family and individual resources only partially influence educational participation. This indicates that refugee students and their parents have only limited options for action concerning their educational participation. Thus, our study shows that educational policies in fact matter: the assignment to a federal state plays a significant role in determining the duration until school enrollment, whether one is placed to a grade level age-appropriately, and whether one attends a newcomer class. Most significantly, legal regulations strongly influence refugees\u27 chances of attending a higher school track (Gymnasium). Due to the low permeability of the German education system, this creates path dependencies for the further education and career paths of new immigrant students. (DIPF/Orig.

Single-use primary capture technology with the promise to deliver new standards for the economics, convenience and reliability of mAb bioprocessing

Product capture chromatography has been crucial in the process development and manufacture of mAb therapeutics over the past 20 years, and in particular Protein A affinity. Chromatography is a step that has had a lot of process development time attributed to getting packed beds to perform to their maximum capability and most of the optimisation stems from limitations of the inherent media and its pack form, such as mass transfer & pressure drop limitations, channeling and bead-wall support effects. The limited throughput that this media offers has prevented this unit operation from being economically accessible in a single-use format. Here we present 3 case studies of work using this a novel nanofibre adsorbent which takes the well-developed performance characteristics of chromatography utilising the same chemical base materials and process infrastructure and delivers a productivity improvement of 50-fold while maintaining product CQAs. This huge throughput advantage enables the drug manufacture to choose whether they want to reduce this unit process size such that the chromatography cartridge’s lifetime (in terms of cycles) can be exhausted over a single batch, with the aim of making in single-use operation economically feasible, or whether they what to trade that off with operating their unit operation in a significantly reduced time period. The goal of this is not just to reduce COGs associated with chromatography, but to enable new overall processing strategies to be employed giving drug manufacturers greater flexibility in their choice of operations and thereby maximising the productivity of new and existing drug manufacturing facilities. The work presented here explores the physical properties that enable this high productivity operation and discusses the resulting product characterisation and process considerations. The industrial suitability of the nanofibre technology has been tested across a 1,000x increase in scale. Initial development work focused on high-throughput screening studies on the Tecan liquid handling system (10-50μL) and lab scale (125μL-1mL nanofibre volume). Run times of less than 3 minutes allowed the impact of key process parameters on quality attributes such as host cell protein and product concentration to be quickly optimised. This work was then scaled to a pilot purification of a 50L CHO cell culture in a single batch. In this initial feasibility study, using a 10mL prototype housing unit, a productivity of 460g/L/h was achieved, with a recovery yield over 90%. A 3-log reduction in host cell proteins was also maintained over 200 cycles, and the Protein A leaching was less than 7ppm. Please click Additional Files below to see the full abstract