562 research outputs found

    The Age Pension Means Tests: Contorting Australian Retirement

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    Most Australian retirees are likely to be subject to the Age Pension assets or income test at some point. Evidence is that many retirees adapt their consumption to increase Age Pension entitlements, but long-term implications are difficult to determine—even if the current rules were to remain in place. This chapter evaluates the current approach to means testing against the principles set out in a Department of Social Services discussion paper on this topic. We evaluate the implied “effective marginal tax rates” (EMTRs) on the assets of part pensioners who are subject to the assets test. We find that depending on a variety of parameters such as assumed future earnings rates, demographic status, drawdown strategy and the base level of assets held, the EMTRs are high enough to explain material distortions to savings decisions of those still in employment, and the spending and investment decisions of retirees. Optimal decisions in this context require contorted retirement strategies that do not appear to be in anyone’s interest. Some possible remedies are suggested, which should include incorporating the value of the principal residence within the assets test. The chapter therefore illustrates the application of principled analysis to policy issues of this sort

    Grasping for the Task:Human Principles for Robot Hands

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    The significant advances made in the design and construction of anthropomorphic robot hands, endow them with prehensile abilities reaching that of humans. However, using these powerful hands with the same level of expertise that humans display is a big challenge for robots. Traditional approaches use finger-tip (precision) or enveloping (power) methods to generate the best force closure grasps. However, this ignores the variety of prehensile postures available to the hand and also the larger context of arm action. This thesis explores a paradigm for grasp formation based on generating oppositional pressure within the hand, which has been proposed as a functional basis for grasping in humans (MacKenzie and Iberall, 1994). A set of opposition primitives encapsulates the hand's ability to generate oppositional forces. The oppositional intention encoded in a primitive serves as a guide to match the hand to the object, quantify its functional ability and relate this to the arm. In this thesis we leverage the properties of opposition primitives to both interpret grasps formed by humans and to construct grasps for a robot considering the larger context of arm action. In the first part of the thesis we examine the hypothesis that hand representation schemes based on opposition are correlated with hand function. We propose hand-parameters describing oppositional intention and compare these with commonly used methods such as joint angles, joint synergies and shape features. We expect that opposition-based parameterizations, which take an interaction-based perspective of a grasp, are able to discriminate between grasps that are similar in shape but different in functional intent. We test this hypothesis using qualitative assessment of precision and power capabilities found in existing grasp taxonomies. The next part of the thesis presents a general method to recognize oppositional intention manifested in human grasp demonstrations. A data glove instrumented with tactile sensors is used to provide the raw information regarding hand configuration and interaction force. For a grasp combining several cooperating oppositional intentions, hand surfaces can be simultaneously involved in multiple oppositional roles. We characterize the low-level interactions between different surfaces of the hand based on captured interaction force and reconstructed hand surface geometry. This is subsequently used to separate out and prioritize multiple and possibly overlapping oppositional intentions present in the demonstrated grasp. We evaluate our method on several human subjects across a wide range of hand functions. The last part of the thesis applies the properties encoded in opposition primitives to optimize task performance of the arm, for tasks where the arm assumes the dominant role. For these tasks, choosing the strongest power grasp available (from a force-closure sense) may constrain the arm to a sub-optimal configuration. Weaker grasp components impose fewer constraints on the hand, and can therefore explore a wider region of the object relative pose space. We take advantage of this to find the good arm configurations from a task perspective. The final hand-arm configuration is obtained by trading of overall robustness in the grasp with ability of the arm to perform the task. We validate our approach, using the tasks of cutting, hammering, screw-driving and opening a bottle-cap, for both human and robotic hand-arm systems

    On Computing Task-Oriented Grasps

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    This paper addresses the problem of optimal grasping of an object with a multi-fingered robotic hand for accomplishing a given task. The task is first demonstrated by a human operator and its force/torque requirements are captured through the usage of a sensorized tool. The grasp quality is computed through a task compatibility criterion. Grasp synthesis is then formulated as a single constrained optimization problem, generating grasps that are feasible for the hand’s kinematics by maximizing the corresponding task-oriented quality criterion and ensuring grasp stability. The method was validated on a human hand model and is shown to be easily adapted to different hand kinematic models

    Towards comprehensive capture of human grasping and manipulation skills

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    Grasping plays a central role in our daily life. To interact with objects surrounding them, people use a large diversity of hand configurations in combination with forces ranging from the small ones involved in manipulating a pen for writing, to larger forces such as when drinking a cup full of water, and even larger ones such as when wielding a hammer. In this paper we present a setup to capture human hand configuration and motion as well as the forces applied by the hand on objects while performing a task. Hand configuration is obtained through the use of a data glove device while interaction forces are measured through an array of tactile sensors. Current approaches in the state-of-the-art are limited in that they only measure interaction forces on the fingers or the palm, ignoring the important role of the sides of the fingers in achieving a grasp/manipulation task. We propose a new setup for a “sensorized” data glove to address these limitations and through which a more complete picture of human hand response in grasping and manipulation can be obtained. This setup was successfully tested on five subjects performing a variety of different tasks

    A modular approach to learning manipulation strategies from human demonstration

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    Object manipulation is a challenging task for robotics, as the physics involved in object interaction is com- plex and hard to express analytically. Here we introduce a modular approach for learning a manipulation strategy from human demonstration. Firstly we record a human perform- ing a task that requires an adaptive control strategy in differ- ent conditions, i.e. different task contexts. We then perform modular decomposition of the control strategy, using phases of the recorded actions to guide segmentation. Each mod- ule represents a part of the strategy, encoded as a pair of forward and inverse models. All modules contribute to the final control policy; their recommendations are integrated via a system of weighting based on their own estimated er- ror in the current task context. We validate our approach by demonstrating it, both in a simulation for clarity, and on a real robot platform to demonstrate robustness and capacity to generalise. The robot task is opening bottle caps. We show that our approach can modularize an adaptive control strategy and generate appropriate motor commands for the robot to accomplish the complete task, even for novel bottles

    Combined Immunodeficiency With Late-Onset Progressive Hypogammaglobulinemia and Normal B Cell Count in a Patient With RAG2 Deficiency

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    Proteins expressed by recombination activating genes 1 and 2 (RAG1/2) are essential in the process of V(D)J recombination that leads to generation of the T and B cell repertoires. Clinical and immunological phenotypes of patients with RAG deficiencies correlate well to the degree of impaired RAG activity and this has been expanding to variants of combined immunodeficiency (CID) or even milder antibody deficiency syndromes. Pathogenic variants that severely impair recombinase activity of RAG1/2 determine a severe combined immunodeficiency (SCID) phenotype, whereas hypomorphic variants result in leaky (partial) SCID and other immunodeficiencies. We report a patient with novel pathogenic compound heterozygous RAG2 variants that result in a CID phenotype with two distinctive characteristics: late-onset progressive hypogammaglobulinemia and highly elevated B cell count. In addition, the patient had early onset of infections, T cell lymphopenia and expansion of lymphocytes after exposure to herpes family viruses. This case highlights the importance of considering pathogenic RAG variants among patients with preserved B cell count and CID phenotype

    Preclinical Development of a Lentiviral Vector for Gene Therapy of X-Linked Severe Combined Immunodeficiency

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    X-linked severe combined immunodeficiency (SCID-X1) is caused by mutations in the interleukin-2 receptor \u3b3 chain gene (IL2RG), and it is characterized by profound defects in T, B, and natural killer (NK) cell functions. Transplantation of hematopoietic stem/progenitor cells (HSPCs) genetically corrected with early murine leukemia retrovirus (MLV)-derived gammaretroviral vectors showed restoration of T cell immunity in patients, but it resulted in vector-induced insertional oncogenesis. We developed a self-inactivating (SIN) lentiviral vector carrying a codon-optimized human IL2RG cDNA driven by the EF1\u3b1 short promoter (EFS-IL2RG), and we tested its efficacy and safety in vivo by transplanting transduced Il2rg-deficient Lin 12 HSPCs in an Il2rg 12/ 12/Rag2 12/ 12 mouse model. The study showed restoration of T, B, and NK cell counts in bone marrow and peripheral blood and normalization of thymus and spleen cellularity and architecture. High-definition insertion site analysis defined the EFS-IL2RG genomic integration profile, and it showed no sign of vector-induced clonal selection or skewing in primarily and secondarily transplanted animals. The study enables a phase I/II clinical trial aimed at restoring both T and B cell immunity in SCID-X1 children upon non-myeloablative conditioning

    Defining the molecular role of gp91phox in the immune manifestation of acute allergic asthma using a preclinical murine model

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    <p>Abstract</p> <p>Objective</p> <p>The phenomena manifested during inflammation require interplay between circulating effector cells, local resident cells, soluble mediators and genetic host factors to establish, develop and maintain itself. Of the molecues involed in the initiation and perpetuation of acute allergic inflammation in asthma, the involvement of effector cells in redox reactions for producing O<sub>2</sub><sup>- </sup>(superoxide anion) through the mediation of NADPH oxidase is a critical step. Prior data suggest that reactive oxygen species (ROS) produced by NADPH oxidase homologues in non-phagocytic cells play an important role in the regulation of signal transduction, while macrophages use a membrane-associated NADPH oxidase to generate an array of oxidizing intermediates which inactivate MMPs on or near them.</p> <p>Materials and Methods and Treatment</p> <p>To clarify the role of gp91phox subunit of NADPH oxidase in the development and progression of an acute allergic asthma phenotype, we induced allergen dependent inflammation in a gp91<it><sup>phox</sup></it>-/- single knockout and a gp91phox-/-MMP-12-/- double knockout mouse models.</p> <p>Results</p> <p>In the knockout mice, both inflammation and airway hyperreactivity were more extensive than in wildtype mice post-OVA. Although OVA-specific IgE in plasma were comparable in wildtype and knockout mice, enhanced inflammatory cell recruitment from circulation and cytokine release in lung and BALf, accompanied by higher airway resistance as well as Penh in response to methacholine, indicate a regulatory role for NADPH oxidase in development of allergic asthma. While T cell mediated functions like Th2 cytokine secretion, and proliferation to OVA were upregulated synchronous with the overall robustness of the asthma phenotype, macrophage upregulation in functions such as proliferation, and mixed lymphocyte reaction indicate a regulatory role for gp91phox and an overall non-involvement or synergistic involvement of MMP12 in the response pathway (comparing data from gp91phox-/- and gp91phox-/-MMP-12-/- mice).</p
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