The Community Authorization Service: Status and Future

Virtual organizations (VOs) are communities of resource providers and users distributed over multiple policy domains. These VOs often wish to define and enforce consistent policies in addition to the policies of their underlying domains. This is challenging, not only because of the problems in distributing the policy to the domains, but also because of the fact that those domains may each have different capabilities for enforcing the policy. The Community Authorization Service (CAS) solves this problem by allowing resource providers to delegate some policy authority to the VO while maintaining ultimate control over their resources. In this paper we describe CAS and our past and current implementations of CAS, and we discuss our plans for CAS-related research.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics (CHEP03), La Jolla, Ca, USA, March 2003. 9 Pages, PD

Basic Income Simulations for the Province of British Columbia

An important component of the work to be completed by the British Columbia’s Expert Panel on Basic Income is to design simulations to look at how various basic income (BI) models could work in B.C. (B.C. Poverty Reduction, 2018). The intent of these simulations is to identify the potential impacts and financial implications for B.C. residents of different variants of a BI. Given the poverty reduction targets passed by the B.C. government, detailed in Petit and Tedds (2020d), the potential impacts include those on the incidence and the depths of poverty in the province (B.C. Poverty Reduction, n.d.). The panel ran over 16,000 different BI scenarios to consider in B.C., which were modelled using Statistics Canada’s Social Policy Simulation Database and Model (SPSD/M) program. We evaluate different BI scenarios in terms of their implications for a variety of measures, including cost, number of recipients, rates of poverty, depths of poverty, distributional affects, and inequality impacts. This paper provides details regarding these simulations. Our goal in this paper is simply to consider different versions of a basic income in terms of both their cost implications and their implications for poverty reduction. We believe that identifying the most effective variants of a basic income in terms of these two criteria will help sharpen the conversation about the applicability of a basic income as a policy option for B.C

Ferritin is secreted via 2 distinct nonclassical vesicular pathways

Ferritin turnover plays a major role in tissue iron homeostasis, and ferritin malfunction is associated with impaired iron homeostasis and neurodegenerative diseases. In most eukaryotes, ferritin is considered an intracellular protein that stores iron in a nontoxic and bioavailable form. In insects, ferritin is a classically secreted protein and plays a major role in systemic iron distribution. Mammalian ferritin lacks the signal peptide for classical endoplasmic reticulum–Golgi secretion but is found in serum and is secreted via a nonclassical lysosomal secretion pathway. This study applied bioinformatics and biochemical tools, alongside a protein trafficking mouse models, to characterize the mechanisms of ferritin secretion. Ferritin trafficking via the classical secretion pathway was ruled out, and a 2:1 distribution of intracellular ferritin between membrane-bound compartments and the cytosol was observed, suggesting a role for ferritin in the vesicular compartments of the cell. Focusing on nonclassical secretion, we analyzed mouse models of impaired endolysosomal trafficking and found that ferritin secretion was decreased by a BLOC-1 mutation but increased by BLOC-2, BLOC-3, and Rab27A mutations of the cellular trafficking machinery, suggesting multiple export routes. A 13-amino-acid motif unique to ferritins that lack the secretion signal peptide was identified on the BC-loop of both subunits and plays a role in the regulation of ferritin secretion. Finally, we provide evidence that secretion of iron-rich ferritin was mediated via the multivesicular body–exosome pathway. These results enhance our understanding of the mechanism of ferritin secretion, which is an important piece in the puzzle of tissue iron homeostasis

Hydrogel-based scaffolds to support intrathecal stem cell transplantation as a gateway to the spinal cord: clinical needs, biomaterials, and imaging technologies

The prospects for cell replacement in spinal cord diseases are impeded by inefficient stem cell delivery. The deep location of the spinal cord and complex surgical access, as well as densely packed vital structures, question the feasibility of the widespread use of multiple spinal cord punctures to inject stem cells. Disorders characterized by disseminated pathology are particularly appealing for the distribution of cells globally throughout the spinal cord in a minimally invasive fashion. The intrathecal space, with access to a relatively large surface area along the spinal cord, is an attractive route for global stem cell delivery, and, indeed, is highly promising, but the success of this approach relies on the ability of cells 1) to survive in the cerebrospinal fluid (CSF), 2) to adhere to the spinal cord surface, and 3) to migrate, ultimately, into the parenchyma. Intrathecal infusion of cell suspension, however, has been insufficient and we postulate that embedding transplanted cells within hydrogel scaffolds will facilitate reaching these goals. In this review, we focus on practical considerations that render the intrathecal approach clinically viable, and then discuss the characteristics of various biomaterials that are suitable to serve as scaffolds. We also propose strategies to modulate the local microenvironment with nanoparticle carriers to improve the functionality of cellular grafts. Finally, we provide an overview of imaging modalities for in vivo monitoring and characterization of biomaterials and stem cells. This comprehensive review should serve as a guide for those planning pre-clinical and clinical studies on intrathecal stem cell transplantation.Funds provided under the project NanoTech4ALS (ref. ENMed/0008/2015, 13/EuroNanoMed/2016), funded under the EU FP7 M-ERA.NET program, Strategmed 1/233209/12/NCBIR/2015, and NIH R01 NS091100. The FCT distinction attributed to J.M.O. under the Investigator FCT program (IF/01285/2015) is also gratefully acknowledgedinfo:eu-repo/semantics/publishedVersio

Brain meets brawn: why Grid and agents need each other

The Grid and agent communities both develop concepts and mechanisms for open distributed systems, albeit from different perspectives. The Grid community has historically focused on “brawn”: infrastructure, tools, and applications for reliable and secure resource sharing within dynamic and geographically distributed virtual organizations. In contrast, the agents community has focused on “brain”: autonomous problem solvers that can act flexibly in uncertain and dynamic environments. Yet as the scale and ambition of both Grid and agent deployments increase, we see a convergence of interests, with agent systems requiring robust infrastructure and Grid systems requiring autonomous, flexible behaviors. Motivated by this convergence of interests, we review the current state of the art in both areas, review the challenges that concern the two communities, and propose research and technology development activities that can allow for mutually supportive effort