970 research outputs found

    Taxing Retirement Income: Nonqualified Annuities and Distributions from Qualified Accounts

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    This paper explores the current tax treatment of non-qualified immediate annuities and distributions from tax-qualified retirement plans in the United States. First, we describe how immediate annuities held outside retirement accounts are taxed. We conclude that the current income tax treatment of annuities does not substantially alter the incentive to purchase an annuity rather than a taxable bond. We nevertheless find differences across different individuals in the effective tax burden on annuity contracts. Second, we examine an alternative method of taxing annuities that would avoid changing the fraction of the annuity payment that is included in taxable income as the annuitant ages, but would still raise the same expected present discounted value of revenues as the current income tax rule. We find that a shift to a constant inclusion ratio increases the utility of annuitants, and that this increase is greater for more risk averse individuals. Third, we examine how payouts from qualified accounts are taxed, focusing on both annuity payouts and minimum distribution requirements that constrain the feasible time path of nonannuitized payouts. We describe briefly the origins and workings of the minimum distribution rules and we also provide evidence on the fraction of retirement assets potentially affected by these rules.

    Signalling mechanisms driving homeostatic and inflammatory effects of interleukin-15 on tissue lymphocytes

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    There is an intriguing dichotomy in the function of cytokine interleukin-15-at low levels, it is required for the homeostasis of the immune system, yet when it is upregulated in response to pathogenic infections or in autoimmunity, IL-15 drives inflammation. IL-15 associates with the IL-15RĪ± within both myeloid and non-haematopoietic cells, where IL-15RĪ± trans-presents IL-15 in a membrane-bound form to neighboring cells. Alongside homeostatic maintenance of select lymphocyte populations such as NK cells and tissue-resident T cells, when upregulated, IL-15 also promotes inflammatory outcomes by driving effector function and cytotoxicity in NK cells and T cells. As chronic over-expression of IL-15 can lead to autoimmunity, IL-15 expression is tightly regulated. Thus, blocking dysregulated IL-15 and its downstream signalling pathways are avenues for immunotherapy. In this review we discuss the molecular pathways involved in IL-15 signalling and how these pathways contribute to both homeostatic and inflammatory functions in IL-15-dependent mature lymphoid populations, focusing on innate, and innate-like lymphocytes in tissues.</p

    Signalling mechanisms driving homeostatic and inflammatory effects of interleukin-15 on tissue lymphocytes

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    There is an intriguing dichotomy in the function of cytokine interleukin-15-at low levels, it is required for the homeostasis of the immune system, yet when it is upregulated in response to pathogenic infections or in autoimmunity, IL-15 drives inflammation. IL-15 associates with the IL-15RĪ± within both myeloid and non-haematopoietic cells, where IL-15RĪ± trans-presents IL-15 in a membrane-bound form to neighboring cells. Alongside homeostatic maintenance of select lymphocyte populations such as NK cells and tissue-resident T cells, when upregulated, IL-15 also promotes inflammatory outcomes by driving effector function and cytotoxicity in NK cells and T cells. As chronic over-expression of IL-15 can lead to autoimmunity, IL-15 expression is tightly regulated. Thus, blocking dysregulated IL-15 and its downstream signalling pathways are avenues for immunotherapy. In this review we discuss the molecular pathways involved in IL-15 signalling and how these pathways contribute to both homeostatic and inflammatory functions in IL-15-dependent mature lymphoid populations, focusing on innate, and innate-like lymphocytes in tissues.</p

    Household Investment in 529 College Savings Plans and Information Processing Frictions

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    We investigate how information processing frictions contribute to household suboptimal saving and investment behavior. We find that 60% of open accounts in college 529 savings plans are invested suboptimally due to high expenses and tax inefficiency. Such investments yield an expected loss of 9% over the accountsā€™ projected lifetimes. Consistent with information processing frictions contributing to inefficient investment, the extent of investment in suboptimal home-state accounts decreases with household financial literacy and increases with plan document disclosure complexity. Overall, our results suggest that information processing frictions shape householdsā€™ suboptimal investment in college savings plans and reduce their financial well-being

    Conformational Preferences of 3-(Dimethylazinoyl)propanoic Acid as a Function of pH and Solvent; Intermolecular versus Intramolecular Hydrogen Bonding

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    The conformational equilibrium of 3-(dimethylazinoyl)propanoic acid (DMAPA, azinoyl = N^+(O^āˆ’) has a weak pH-dependence in D_2O, with a slight preference for trans in alkaline solutions. The acid ionization constants of the protonated amine oxide and carboxylic functional groups as determined by NMR spectroscopy were 7.9 Ɨ 10^(āˆ’4) and 6.3 Ɨ 10^(āˆ’6), respectively. The corresponding value of K_1/K_2 of 1.3 Ɨ 10^2 is not deemed large enough to provide experimental NMR evidence for a significant degree of intramolecular hydrogen bonding in D_2O. Conformational preferences of DMAPA are mostly close to statistical (gauche/trans = 2/1) in other protic solvents, e.g., alcohols. However, the un-ionized form of DMAPA appears to be strongly intramolecularly hydrogen-bonded and gauche in aprotic solvents

    A Role for Actin, Cdc1p, and Myo2p in the Inheritance of Late Golgi Elements in \u3cem\u3eSaccharomyces cerevisiae\u3c/em\u3e

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    In Saccharomyces cerevisiae, Golgi elements are present in the bud very early in the cell cycle. We have analyzed this Golgi inheritance process using fluorescence microscopy and genetics. In rapidly growing cells, late Golgi elements show an actin-dependent concentration at sites of polarized growth. Late Golgi elements are apparently transported into the bud along actin cables and are also retained in the bud by a mechanism that may involve actin. A visual screen for mutants defective in the inheritance of late Golgi elements yielded multiple alleles of CDC1. Mutations in CDC1 severely depolarize the actin cytoskeleton, and these mutations prevent late Golgi elements from being retained in the bud. The efficient localization of late Golgi elements to the bud requires the type V myosin Myo2p, further suggesting that actin plays a role in Golgi inheritance. Surprisingly, early and late Golgi elements are inherited by different pathways, with early Golgi elements localizing to the bud in a Cdc1p- and Myo2p-independent manner. We propose that early Golgi elements arise from ER membranes that are present in the bud. These two pathways of Golgi inheritance in S. cerevisiae resemble Golgi inheritance pathways in vertebrate cells

    Developing Civic-Mindedness in Middle- and High-School Students Using Service-Learning

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    Education is not only about teaching students in academic domains, but also teaching them about the application of those domains in society as civic-minded, engaged citizens. Service learning projects can be effective at fostering a sense of civic-mindedness in students, at least in college (e.g., Weber & Weber, 2010). During the 2017-2018 school year, we conducted a case study with 73 middle school students from two rural schools in the Arkansas Delta to examine, in part, the impact of one service-learning initiative (EAST). Participating students researched authentic problems in their communities and developed projects aimed at addressing those problems. Based on data from the case study, students appeared to become more aware of problems in their communities and believed they could help to solve those problems. Using the EAST model, this proposed session will examine how service-learning projects can help secondary educators develop civic-mindedness in students

    Genetic Approach to Elucidate the Role of Cyclophilin D in Traumatic Brain Injury Pathology

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    Cyclophilin D (CypD) has been shown to play a critical role in mitochondrial permeability transition pore (mPTP) opening and the subsequent cell death cascade. Studies consistently demonstrate that mitochondrial dysfunction, including mitochondrial calcium overload and mPTP opening, is essential to the pathobiology of cell death after a traumatic brain injury (TBI). CypD inhibitors, such as cyclosporin A (CsA) or NIM811, administered following TBI, are neuroprotective and quell neurological deficits. However, some pharmacological inhibitors of CypD have multiple biological targets and, as such, do not directly implicate a role for CypD in arbitrating cell death after TBI. Here, we reviewed the current understanding of the role CypD plays in TBI pathobiology. Further, we directly assessed the role of CypD in mediating cell death following TBI by utilizing mice lacking the CypD encoding gene Ppif. Following controlled cortical impact (CCI), the genetic knockout of CypD protected acute mitochondrial bioenergetics at 6 h post-injury and reduced subacute cortical tissue and hippocampal cell loss at 18 d post-injury. The administration of CsA following experimental TBI in Ppif-/- mice improved cortical tissue sparing, highlighting the multiple cellular targets of CsA in the mitigation of TBI pathology. The loss of CypD appeared to desensitize the mitochondrial response to calcium burden induced by TBI; this maintenance of mitochondrial function underlies the observed neuroprotective effect of the CypD knockout. These studies highlight the importance of maintaining mitochondrial homeostasis after injury and validate CypD as a therapeutic target for TBI. Further, these results solidify the beneficial effects of CsA treatment following TBI

    Pre-treatment effects on coral skeletal delta\u3csup\u3e13\u3c/sup\u3eC and delta\u3csup\u3e18\u3c/sup\u3eO

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    Pre-treatments are often used to remove organic ā€œcontaminantā€ material prior to isotopic analyses of coral skeletal samples. Here we conducted three experiments to test the pre-treatment effect of water, 30% hydrogen peroxide (H2O2), and household bleach [5.25% sodium hypochlorite (NaClO3) and 0.15% sodium hydroxide (NaOH)], on the stable isotopic composition of coral skeletal samples. First, using a mass balance approach we calculated the expected change in skeletal delta13C due to the removal of all organic carbon. The model showed that (1) the removal of organic carbon (which has a low delta13C value relative to skeletal delta13C) from the skeletal sample should theoretically result in a higher delta13C value of the remaining organic-carbon-free carbonate, and that (2) only at the highest concentrations of skeletal organic carbon within the tissue layer of corals is the contribution of the organic carbon to the overall delta13C skeletal value potentially large enough to be detectable by mass spectrometry. We then conducted two sets of experiments to test the model where we pre-treated a large number of skeletal samples from five species of corals with water, H2O2, bleach, or no pre-treatment for 24 h. Skeletal delta13C generally decreased significantly with water, bleach, and H2O2 pre-treatments which is contrary to the model-predicted increase in delta13C following such pre-treatments. Thus, organic carbon within the skeleton is not a net source of contamination to delta13C analyses. Skeletal delta18O decreased the most with water and bleach pre-treatments. In addition, the effect of H2O2 or bleach pre-treatments on either delta13C or delta18O was not consistent among species or locations. The direction of change in delta13C and delta18O with pre-treatments was no different for skeletal samples taken within or below the tissue layer. Based on our results, we suggest that pre-treatment is not necessary and recommend that pre-treatment not be performed on coral skeletal samples prior to stable isotope analysis to avoid any pre-treatment-induced variability that could significantly compromise inter-colony and inter-species comparisons

    A framework for automated anomaly detection in high frequency water-quality data from in situ sensors

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    River water-quality monitoring is increasingly conducted using automated in situ sensors, enabling timelier identification of unexpected values. However, anomalies caused by technical issues confound these data, while the volume and velocity of data prevent manual detection. We present a framework for automated anomaly detection in high-frequency water-quality data from in situ sensors, using turbidity, conductivity and river level data. After identifying end-user needs and defining anomalies, we ranked their importance and selected suitable detection methods. High priority anomalies included sudden isolated spikes and level shifts, most of which were classified correctly by regression-based methods such as autoregressive integrated moving average models. However, using other water-quality variables as covariates reduced performance due to complex relationships among variables. Classification of drift and periods of anomalously low or high variability improved when we applied replaced anomalous measurements with forecasts, but this inflated false positive rates. Feature-based methods also performed well on high priority anomalies, but were also less proficient at detecting lower priority anomalies, resulting in high false negative rates. Unlike regression-based methods, all feature-based methods produced low false positive rates, but did not and require training or optimization. Rule-based methods successfully detected impossible values and missing observations. Thus, we recommend using a combination of methods to improve anomaly detection performance, whilst minimizing false detection rates. Furthermore, our framework emphasizes the importance of communication between end-users and analysts for optimal outcomes with respect to both detection performance and end-user needs. Our framework is applicable to other types of high frequency time-series data and anomaly detection applications
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