Eluate derived by extracorporal antibody-based immunoadsorption elevates the cytosolic Ca2+ concentration in podocytes via B-2 kinin receptors

Background/Aim: Patients with idiopathic focal segmental glomerulosclerosis (FSGS) often develop a recurrence of the disease after kidney transplantation. In a number of FSGS patients, plasmapheresis and immunoadsorption procedures have been shown to transiently reduce proteinuria and are thought to do this by eliminating a circulating factor. Direct cellular effects of eluates from immunoadsorption procedures on podocytes, the primary target of injury in FSGS, have not yet been reported. Methods: Eluates were derived from antibody-based immunoadsorption of a patient suffering from primary FSGS, a patient with systemic lupus erythematosus, and a healthy volunteer. The cytosolic free Ca2+ concentration ({[}Ca2+](i)) of differentiated podocytes was measured by single-cell fura-2 microfluorescence measurements. Free and total immunoreactive kinin levels were measured by radioimmunoassay. Results: FSGS eluates increased the {[}Ca2+](i) levels concentration dependently (EC50 0.14 mg/ml; n = 3-19). 1 mg/ml eluate increased the {[}Ca2+](i) values reversibly from 82 +/- 12 to 1,462 +/- 370 nmol/l, and then they returned back to 100 16 nmol/l (n = 19). The eluate-induced increase of {[}Ca2+](i) consisted of an initial Ca2+ peak followed by a Ca2+ plateau which depended on the extracellular Ca2+ concentration. The eluate-induced increase of {[}Ca2+](i) was inhibited by the specific B-2 kinin receptor antagonist Hoe 140 in a concentration-dependent manner (IC50 2.47 nmol/l). In addition, prior repetitive application of bradykinin desensitized the effect of eluate on {[}Ca2+](i). A colonic epithelial cell line not reacting to bradykinin did not respond to eluate either (n = 6). Similar to FSGS eluates, the eluate preparations of both the systemic lupus patient and the healthy volunteer led to a biphasic, concentration-dependent {[}Ca2+](i) increase in poclocytes which again was inhibited by Hoe 140. Free kinins were detected in all eluate preparations. Conclusion: The procedure of antibody-based immunoadsorption leads to kinin in the eluate which elevates the {[}Ca2+](i) level of podocytes via B-2 kinin receptors. Copyright (C) 2002 S. Karger AG, Basel

Learning to Backdoor Federated Learning

In a federated learning (FL) system, malicious participants can easily embed backdoors into the aggregated model while maintaining the model's performance on the main task. To this end, various defenses, including training stage aggregation-based defenses and post-training mitigation defenses, have been proposed recently. While these defenses obtain reasonable performance against existing backdoor attacks, which are mainly heuristics based, we show that they are insufficient in the face of more advanced attacks. In particular, we propose a general reinforcement learning-based backdoor attack framework where the attacker first trains a (non-myopic) attack policy using a simulator built upon its local data and common knowledge on the FL system, which is then applied during actual FL training. Our attack framework is both adaptive and flexible and achieves strong attack performance and durability even under state-of-the-art defenses

Das Recht auf urbanes Wohnen – wohnungspolitische und wirtschaftsethische Herausforderungen

Das Recht auf Wohnen ist in den meisten Verfassungen der Welt explizit oder implizit fest verankert, so auch in Deutschland. Die Realisierung des Rechts auf Wohnen setzt deren Bezahlbarkeit für alle Einkommensschichten sowie den Zugang zum Wohnungsmarkt  voraus. Zur sozialen Absicherung des Wohnens nutzt Deutschland verschiedene Wege, tritt unterschiedlich stark im Wohnungsmarkt als eigenständiger Akteur auf, wählt divergierende Formen objekt- und subjektbezogener Instrumente und kombiniert diese mit regulatorischen Eingriffen. Der Beitrag diskutiert, mit welchen wohnungspolitischen Maßnahmen sich die Umsetzung des Rechts auf Wohnen sowohl effektiv als auch effizient und unter Beachtung ethischer Grundsätze realisieren lässt. Es zeigt sich, dass die aus dem Recht auf Wohnen ableitbaren Teilrechte auf ein „bezahlbares“ und „urbanes“ Wohnen nicht uneingeschränkt gelten (können). Ökonomische und wirtschaftsethische Grenzen werden diskutiert, wie Subsidiarität, Selbstverantwortung, Kosten- Nutzenabwägungen, Markt- und Staatsversagen. Eine vollständige Abfederung sozialer Risiken und regionaler Entwicklungen ist aufgrund hoher volkswirtschaftlicher und gesellschaftlicher Kosten sowie Ungerechtigkeiten andernorts nicht zielführend. Die bei der politischen Festlegung dieser Grenzen auftretenden sozial- und wirtschaftsethischen Dilemmata werden entlang drei zentraler Fragestellungen diskutiert.The right to housing is explicitly or implicitly enshrined in most of the world’s constitutions, including that of Germany. The realization of the right to housing presupposes affordable housing and access to the housing market for all income groups. In order to ensure the social security of housing, the German state uses a variety of methods, acting as an independent actor in the housing market to varying degrees, choosing divergent forms of object-and subject-related instruments, and combining these instruments with regulatory interventions. The article discusses which housing policy measures can be used to implement the right to housing effectively, efficiently, and in compliance with ethical principles. It is shown that the partial rights to “affordable” and “urban” housing that can be derived from the right to housing do not (or cannot) apply without restrictions. Economic and ethical limits are discussed, such as subsidiarity, self-responsibility, cost-benefit trade-offs, market and state failure. Because of high economic and social costs and pervasive injustice, a complete cushioning of social risks and regional developments is not expedient. The social and economic ethical dilemmas that arise in the political definition of these limits are discussed along three central questions

Are Coyotes “Natural”? Differences in Perceptions of Coyotes Among Urban and Suburban Park Users

By 2050 more than 65% of humans are expected to live in urban and suburban areas. This shift has gained the attention of conservation scientists and managers with more focus directed on conflict and coexistence between wildlife and urbanized populations. One species that is increasingly prominent in urban and suburban environments is the coyote (Canis latrans). Coyotes have established themselves as a keystone predator with a regulating effect on prey populations, thus playing an important role in the functioning of the urban ecosystem. However, research has shown that negative perceptions of coyotes are common and contribute to support for eradication-focused management strategies, such as broad-scale trapping or culling, which are expensive and largely ineffective. To better understand coyote acceptance and non-acceptance we conducted a comparative study of park users residing in two counties in the New York metropolitan area: a suburban county, where coyotes are already established, and an urban county, where coyotes have only recently begun to arrive. Our findings suggest that urban respondents have lower levels of coyote acceptance and higher preference for coyote removal than suburban respondents. We tested multiple predictor variables to determine which was the strongest driver of desire for removal: perception of threat to humans and pets, perception of coyote “naturalness” in the environment, and appropriateness of expressed reaction to a hypothetical coyote encounter. We found that perception of coyote “naturalness” was the strongest predictor of whether people felt that coyotes belonged in the region and thus should not be removed. Our results suggest that wildlife coexistence strategies could benefit from messages that instill in residents a sense that their local area is a place where coyotes and other wild animals belong

Border Effects in House Prices

This article estimates the effect of the Dutch–German border on house prices. We argue that the difference between house prices at the border indicates the willingness to pay to stay in a country compared to living across the border. After a change in the tax rules in 2001, migration from the Netherlands to Germany increased substantially and the gradient of Dutch house price towards the German border steepened. Combining a German and Dutch real estate dataset and using different estimation strategies, we find that asking prices of comparable housing drop by about 16% when one crosses the Dutch–German border

A First Order Meta Stackelberg Method for Robust Federated Learning (Technical Report)

Recent research efforts indicate that federated learning (FL) systems are vulnerable to a variety of security breaches. While numerous defense strategies have been suggested, they are mainly designed to counter specific attack patterns and lack adaptability, rendering them less effective when facing uncertain or adaptive threats. This work models adversarial FL as a Bayesian Stackelberg Markov game (BSMG) between the defender and the attacker to address the lack of adaptability to uncertain adaptive attacks. We further devise an effective meta-learning technique to solve for the Stackelberg equilibrium, leading to a resilient and adaptable defense. The experiment results suggest that our meta-Stackelberg learning approach excels in combating intense model poisoning and backdoor attacks of indeterminate types