448 research outputs found

    AdSplit: Separating smartphone advertising from applications

    Full text link
    A wide variety of smartphone applications today rely on third-party advertising services, which provide libraries that are linked into the hosting application. This situation is undesirable for both the application author and the advertiser. Advertising libraries require additional permissions, resulting in additional permission requests to users. Likewise, a malicious application could simulate the behavior of the advertising library, forging the user's interaction and effectively stealing money from the advertiser. This paper describes AdSplit, where we extended Android to allow an application and its advertising to run as separate processes, under separate user-ids, eliminating the need for applications to request permissions on behalf of their advertising libraries. We also leverage mechanisms from Quire to allow the remote server to validate the authenticity of client-side behavior. In this paper, we quantify the degree of permission bloat caused by advertising, with a study of thousands of downloaded apps. AdSplit automatically recompiles apps to extract their ad services, and we measure minimal runtime overhead. We also observe that most ad libraries just embed an HTML widget within and describe how AdSplit can be designed with this in mind to avoid any need for ads to have native code

    Quire: Lightweight Provenance for Smart Phone Operating Systems

    Full text link
    Smartphone apps often run with full privileges to access the network and sensitive local resources, making it difficult for remote systems to have any trust in the provenance of network connections they receive. Even within the phone, different apps with different privileges can communicate with one another, allowing one app to trick another into improperly exercising its privileges (a Confused Deputy attack). In Quire, we engineered two new security mechanisms into Android to address these issues. First, we track the call chain of IPCs, allowing an app the choice of operating with the diminished privileges of its callers or to act explicitly on its own behalf. Second, a lightweight signature scheme allows any app to create a signed statement that can be verified anywhere inside the phone. Both of these mechanisms are reflected in network RPCs, allowing remote systems visibility into the state of the phone when an RPC is made. We demonstrate the usefulness of Quire with two example applications. We built an advertising service, running distinctly from the app which wants to display ads, which can validate clicks passed to it from its host. We also built a payment service, allowing an app to issue a request which the payment service validates with the user. An app cannot not forge a payment request by directly connecting to the remote server, nor can the local payment service tamper with the request

    Challenges with Point-Of-Care Tests (POCT) for Celiac Disease

    Get PDF
    Current screening test for celiac disease involves blood test in centralized pathology laboratories, typically performing enzyme-linked immune-sorbent assays (ELISA) to detect specific celiac disease antibodies. Most of the current available celiac disease antibody tests detect anti-gliadin (AGA), anti-endomysial (EMA), anti-transglutaminase (tTG), or deamidated gluten peptide (DGP) antibodies from serum or whole blood samples. It requires blood collection from untreated celiac patients, which is often invasive and inconvenient. There is a rapid growth in demand for noninvasive celiac tests for the early and fast diagnosis of celiac disease to help potential celiac patients obtain results and take corresponding actions. Over the last decade, several point-of-care tests (POCT) have been introduced to the market, but these tests have not been widely accepted by clinicians. Moreover, the 2009 NICE guideline CG 86 recommended that self-tests and/or POCT for celiac disease should not be used as a substitute for laboratory-based tests. Here, we provide a background on the evolution of POCT for celiac disease. We discuss general principle of operation for the known commercial kits as well as the use of various antigens and antibodies in different tests developed over the years. Finally, we discuss challenges for future research directions in celiac disease POCTs

    Comparison of Protective Immune Responses to Apicomplexan Parasites

    Get PDF
    Members of the phylum Apicomplexa, which includes the species Plasmodium, Eimeria, Toxoplasma, and Babesia amongst others, are the most successful intracellular pathogens known to humankind. The widespread acquisition of antimicrobial resistance to most drugs used to date has sparked a great deal of research and commercial interest in the development of vaccines as alternative control strategies. A few antigens from the asexual and sexual stages of apicomplexan development have been identified and their genes characterised; however, the fine cellular and molecular details of the effector mechanisms crucial for parasite inhibition and stimulation of protective immunity are still not entirely understood. This paper provides an overview of what is currently known about the protective immune response against the various types of apicomplexan parasites and focuses mainly on the similarities of these pathogens and their host interaction. Finally, the evolutionary relationships of these parasites and their hosts, as well as the modulation of immune functions that are critical in determining the outcome of the infection by these pathogenic organisms, are discussed

    Diffusion Of Responsibility And Level Of Risk Taking In Groups 1

    Full text link
    This study reports evidence supporting the following propositions: (1) Group discussion and consensus concerning decisions that involve actual risk ana payoffs lead to greater risk taking than occurs in the absence of such discussion and consensus. (2) The mechanism that underlies this group‐induced shift toward greater risk taking consists of a diffusion or spreading of responsibility. Using risks and payoffs based on monetary gain and loss for problem‐solving performance, the above propositions received strong confirmation for male college subjects. The results of various experimental manipulations provided positive support for viewing diffusion of responsibility as the causal factor at work.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/108279/1/ets200956.pd

    Group Influence On Individual Risk Taking 1

    Full text link
    Does group interaction lead to greater conservatism or to greater risk taking in decisions than would obtain were the decisions arrived at individually.–or is there an averaging effect? This question was investigated with a procedure in which the protagonist in each of 12 everyday life situations must choose between two courses of action, one of which involves considerably more risk than the other but also is much more rewarding if successful. The S must decide on the lowest level of probability for the success of the risky alternative that he would deem sufficient to warrant its choice. A total of 218 liberal arts university students participated in the study. In the experimental condition, the S s first arrived at individual decisions concerning each of the 12 situations; then, they were brought together in discussion groups of six with the request that they reach a group consensus on each decision; and afterward, they were asked to make all their decisions privately once again. Some S s also made private decisions yet another time two to six weeks later. The group members' judgments of one another's relative degrees of influence and of popularity within the group also were obtained. There were 14 all‐male and 14 all‐female groups. In the control condition, S s made their decisions individually each of two times with one week intervening, under instructions the second time that encouraged them to change rather than simply to recall their earlier decisions. It was found that (1) group decisions exhibit greater risk taking than appears in pre‐discussion individual decisions; (2) post‐discussion private decisions exhibit the same increase in risk taking as occurs in the group decisions; (3) the increase in risk taking resulting from the discussion process is still maintained after a subsequent period of two to six weeks has elapsed; (4) no shift in risk taking level occurs over time in the absence of the discussion process; and (5) degree of risk taking in pre‐discussion individual decisions and degree of judged influence within the group are positively related. Two interpretations of these findings were suggested, either or both of which may apply: (1) the knowledge that one's decisions are being made jointly with others leads to a diffusion of personal responsiblity, the outcome of which is an increased willingness to take risks; (2) high risk takers are more likely to take the initiative in social situations, with the result that they become more influential in the group.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/108371/1/ets200112.pd

    Field Application of a Subunit Vaccine against an Enteric Protozoan Disease

    Get PDF
    Background: Coccidiosis is a major global veterinary health problem in intensively reared chickens. It is caused by apicomplexan parasites of the genus Eimeria. Principal Findings: A subunit vaccine composed of purified antigens from the gametocytes of Eimeria maxima was used to stimulate the production and transfer of maternal antibodies between breeding hens and their hatchlings. The vaccine was injected into hens twice before they began laying eggs. Immunization had no adverse affects on egg laying or health of the hens and resulted in high antibody levels throughout the life of the hens. Progeny of immunized hens excreted significantly less oocysts of various species of Eimeria in their faeces than chicks from unvaccinated hens. Furthermore, the offspring of vaccinated hens developed stronger natural immunity to Eimeria, so that they were resistant to challenge infection even at 8 weeks of age, well after all maternal antibodies had left their circulation. Field trials were conducted in South Africa, Brazil and Thailand, involving at least 1 million progeny of vaccinated hens and at least 1 million positive control birds (raised on feed containing anticoccidial drugs or immunized with a live vaccine) in each country. Additionally, trials were carried out in Israel involving 60 million progeny of vaccinated hens and 112 million positive control birds. There were no significant differences in growth rate, feed conversion ratios or mortality in the offspring of vaccinated hens compared with the positive control chickens in any of these countries regardless of different management practices, different breeds of chickens or climate. Conclusions: These results demonstrate that a vaccine composed of antigens purified from the gametocytes of Eimeria can be used safely and effectively to prevent the deleterious effects of coccidiosis. It is the first subunit vaccine against any protozoan parasite to be successfully applied on a commercial scale. © 2008 Wallach et al

    Gevrey functions and ultradistributions on compact Lie groups and homogeneous spaces

    Get PDF
    In this paper we give global characterisations of Gevrey-Roumieu and Gevrey-Beurling spaces of ultradifferentiable functions on compact Lie groups in terms of the representation theory of the group and the spectrum of the Laplace-Beltrami operator. Furthermore, we characterise their duals, the spaces of corresponding ultradistributions. For the latter, the proof is based on first obtaining the characterisation of their α\alpha-duals in the sense of Koethe and the theory of sequence spaces. We also give the corresponding characterisations on compact homogeneous spaces.Comment: 23 page
    corecore