69 research outputs found

    Contract Design in Insurance Groups

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    In many rural settings, informal mutual support networks have evolved into semiformal insurance groups, such as funeral societies. Using detailed panel data for six villages in Ethiopia, we can distinguish two types of contracts, in terms of whether payments are only made at the time of death or savings are accumulated by the group based on premiums paid ex-ante. We characterize these contracts as the coalition-proof equilibria of a symmetric and stationary risk-sharing game, and we show numerically that a contract with savings makes higher demands on enforceability, leading to less cohesive groups finding it in their interest to choose the contract without savings and that coalitionproofness is a necessary condition for the coexistence of both contract types. We show in the data that the type of contract chosen by groups is correlated with the level of trust and other enforcement improving factors. We also predict that among the observed contracts, those with group-based savings and ex-ante payments will attain higher welfare in terms of consumption smoothing than those observed using no group savings. Using panel data, and controlling for household fixed effects and time-varying village level fixed effects, we show that funeral groups are vehicles for risk-sharing and that contract type matters for performance in line with these predictions. The results appear robust to endogeneity of group formation and endogenous selection into contract types.

    Cardinals as Ultrapowers : A Canonical Measure Analysis under the Axiom of Determinacy

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    This thesis is in the field of Descriptive Set Theory and examines some consequences of the Axiom of Determinacy concerning partition properties that define large cardinals. The Axiom of Determinacy (AD) is a game-theoretic statement expressing that all infinite two-player perfect information games with a countable set of possible moves are determined, i.e., admit a winning strategy for one of the players. By the term "measure analysis'' we understand the following procedure: given a strong partition cardinal κ and some cardinal λ > κ, we assign a measure µ on κ to λ such that the ultrapower with respect to µ equals λ . A canonical measure analysis is a measure assignment for cardinals larger than a strong partition cardinal κ and a binary operation on the measures of this assignment that corresponds to ordinal addition on indices of the cardinals. This thesis provides a canonical measure analysis up to the (ω^ω)th cardinal after an odd projective cardinal. Using this canonical measure analysis we show that all cardinals that are ultrapowers with respect to basic order measures are Jónsson cardinals. With the canonicity results of this thesis we can state that, if κ is an odd projective ordinal, κ^(n), κ^(ωn+1), and κ^(ω^n+1), for n<ω, are Jónsson under AD

    Group-based Funeral Insurance in Ethiopia and Tanzania

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    A funeral is a costly occasion. This paper studies indigenous insurance institutions developed to cope with the high costs of funerals, based on evidence from rural areas in Tanzania and Ethiopia. These institutions are based on well-defined rules and regulations, often offering premium-based insurance for funeral expenses. Increasingly, they are also offering other forms of insurance and credit to cope with hardship. The paper argues that the characteristics and inclusiveness of these institutions make them well-placed as models to broaden insurance provision and other developmental activities in these communities. The history of these institutions is characterised by a resistance to attempts of political capture, and helps to understand their apparent resistance to engage more broadly with NGOs and government agencies. As a result, any attempt to expand their activities will have to be done cautiously.Risk-Sharing, Insurance, Africa, Ethiopia, Tanzania

    Membership Based Indigenous Insurance Associationsin Ethiopia and Tanzania

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    Indigenous insurance associations are a prevalent form of membership based organisations of the poor, at least in the rural areas in Ethiopia and Tanzania surveyed by the authors. Results show how villagers with few links to any formal kind of insurance market have established membership-based indigenous insurance associations to protect themselves against unexpected expenditures, mainly for funerals and hospitalisation. Many of these institutions tend to co-exist within the same community and are based on well-defined rules and regulations, well beyond informal reciprocal relations. They tend to offer premium-based insurance for funeral expenses, as well as, in many cases, other forms of insurance and credit to help address hardship. These groups are completely owned and managed by their members. They were locally initiated and have been continually developing through the actions of their own members, without involvement from the government or donors. Using detailed group membership data linked to household survey data we show that (i) these institutions are widely prevalent in the surveyed areas, (ii) households typically belong to several groups at the same time, (iii) they display a large degree of inclusiveness and (iv) they insure an important part of some shocks, but still leave households prone to the effects of risk

    A High-Throughput Screen for Tuberculosis Progression

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    One-third of the world population is infected with Mycobacterium tuberculosis and multi-drug resistant strains are rapidly evolving. The noticeable absence of a whole organism high-throughput screening system for studying the progression of tuberculosis is fast becoming the bottleneck in tuberculosis research. We successfully developed such a system using the zebrafish Mycobacterium marinum infection model, which is a well-characterized model for tuberculosis progression with biomedical significance, mimicking hallmarks of human tuberculosis pathology. Importantly, we demonstrate the suitability of our system to directly study M. tuberculosis, showing for the first time that the human pathogen can propagate in this vertebrate model, resulting in similar early disease symptoms to those observed upon M. marinum infection. Our system is capable of screening for disease progression via robotic yolk injection of early embryos and visual flow screening of late-stage larvae. We also show that this system can reliably recapitulate the standard caudal vein injection method with a throughput level of 2,000 embryos per hour. We additionally demonstrate the possibility of studying signal transduction leading to disease progression using reverse genetics at high-throughput levels. Importantly, we use reference compounds to validate our system in the testing of molecules that prevent tuberculosis progression, making it highly suited for investigating novel anti-tuberculosis compounds in vivo

    Omeprazole Inhibits Proliferation and Modulates Autophagy in Pancreatic Cancer Cells

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    BACKGROUND: Omeprazole has recently been described as a modulator of tumour chemoresistance, although its underlying molecular mechanisms remain controversial. Since pancreatic tumours are highly chemoresistant, a logical step would be to investigate the pharmacodynamic, morphological and biochemical effects of omeprazole on pancreatic cancer cell lines. METHODOLOGY/PRINCIPAL FINDINGS: Dose-effect curves of omeprazole, pantoprazole, gemcitabine, 5-fluorouracil and the combinations of omeprazole and 5-fluorouracil or gemcitabine were generated for the pancreatic cancer cell lines MiaPaCa-2, ASPC-1, Colo357, PancTu-1, Panc1 and Panc89. They revealed that omeprazole inhibited proliferation at probably non-toxic concentrations and reversed the hormesis phenomena of 5-fluorouracil. Electron microscopy showed that omeprazole led to accumulation of phagophores and early autophagosomes in ASPC-1 and MiaPaCa-2 cells. Signal changes indicating inhibited proliferation and programmed cell death were found by proton NMR spectroscopy of both cell lines when treated with omeprazole which was identified intracellularly. Omeprazole modulates the lysosomal transport pathway as shown by Western blot analysis of the expression of LAMP-1, Cathepsin-D and β-COP in lysosome- and Golgi complex containing cell fractions. Acridine orange staining revealed that the pump function of the vATPase was not specifically inhibited by omeprazole. Gene expression of the autophagy-related LC3 gene as well as of Bad, Mdr-1, Atg12 and the vATPase was analysed after treatment of cells with 5-fluorouracil and omeprazole and confirmed the above mentioned results. CONCLUSIONS: We hypothesise that omeprazole interacts with the regulatory functions of the vATPase without inhibiting its pump function. A modulation of the lysosomal transport pathway and autophagy is caused in pancreatic cancer cells leading to programmed cell death. This may circumvent common resistance mechanisms of pancreatic cancer. Since omeprazole use has already been established in clinical practice these results could lead to new clinical applications

    A Roadmap for HEP Software and Computing R&D for the 2020s

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    Particle physics has an ambitious and broad experimental programme for the coming decades. This programme requires large investments in detector hardware, either to build new facilities and experiments, or to upgrade existing ones. Similarly, it requires commensurate investment in the R&D of software to acquire, manage, process, and analyse the shear amounts of data to be recorded. In planning for the HL-LHC in particular, it is critical that all of the collaborating stakeholders agree on the software goals and priorities, and that the efforts complement each other. In this spirit, this white paper describes the R&D activities required to prepare for this software upgrade.Peer reviewe

    Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

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    A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

    Measurements of top-quark pair differential cross-sections in the eμe\mu channel in pppp collisions at s=13\sqrt{s} = 13 TeV using the ATLAS detector

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