| 1. |
- Aharonian, Felix, et al.
(author)
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Atmospheric gas dynamics in the Perseus cluster observed with Hitomi
- 2018
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In: Publications of the Astronomical Society of Japan. - : Oxford University Press (OUP). - 0004-6264 .- 2053-051X. ; 70:2
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Journal article (peer-reviewed)abstract
- Extending the earlier measurements reported in Hitomi collaboration (2016, Nature, 535, 117), we examine the atmospheric gas motions within the central 100 kpc of the Perseus cluster using observations obtained with the Hitomi satellite. After correcting for the point spread function of the telescope and using optically thin emission lines, we find that the line-of-sight velocity dispersion of the hot gas is remarkably low and mostly uniform. The velocity dispersion reaches a maxima of approximately 200 km s(-1) toward the central active galactic nucleus (AGN) and toward the AGN inflated northwestern ghost bubble. Elsewhere within the observed region, the velocity dispersion appears constant around 100 km s(-1). We also detect a velocity gradient with a 100 km s(-1) amplitude across the cluster core, consistent with large-scale sloshing of the core gas. If the observed gas motions are isotropic, the kinetic pressure support is less than 10% of the thermal pressure support in the cluster core. The well-resolved, optically thin emission lines have Gaussian shapes, indicating that the turbulent driving scale is likely below 100 kpc, which is consistent with the size of the AGN jet inflated bubbles. We also report the first measurement of the ion temperature in the intracluster medium, which we find to be consistent with the electron temperature. In addition, we present a new measurement of the redshift of the brightest cluster galaxy NGC 1275.
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| 2. |
- Bruér, Mattias, 1974-
(author)
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Empirical Studies in Demography and Macroeconomics
- 2004
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Doctoral thesis (other academic/artistic)abstract
- Essay 1 examines the age-structure effects on Swedish inflation both within sample and out-of-sample. Within sample, time-series regressions indicate age structure to have significant explanatory power on Swedish inflation. The relative age-structure effects are well in accordance with both the life-cycle hypothesis and the Phillips-Okun relationship. In the forecasting exercise, the age models outperform the estimated benchmarks; i.e. two autoregressive models, an ARIMA and the two-per cent forecast corresponding to the inflation target. The age models are also considerably better than the consensus forecasts and they are equal in merit to a general VAR model that has been used by the Bank of Sweden. Essay 2 contributes to the existing literature in several ways. It is the first study emphasizing the importance of age-structure effects on real exchange rates within the class of fundamental-based models and it is also among the first examining age-structure effects on real exchange rates in general. In particular, age structure is hypothesized to be related to real exchange rates mainly via its effects on the current account. The estimated reduced-form models strongly support this view.Essay 3 tests the one-for-one relationship between inflation and nominal interest rates -- the strong version of the Fisher Hypothesis -- on an OECD panel. In contrast to previous studies on the Fisher Hypothesis, testing is carried out in a panel context. Exploring the panel dimension, the power and efficiency of the tests for unit roots and cointegration are increased. Furthermore, panel tests are especially well suited when the sample period is relatively short, but where links or similarities across countries are present. Utilizing this property of the panel tests, it is examined whether the evidence in favor of the Fisher Hypothesis is stronger when markets are deregulated.
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| 3. |
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| 4. |
- Jock, Janet, et al.
(author)
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Effects of pension eligibility expansion on men’s cognitive function : findings from rural South Africa
- 2023
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In: Journal of Aging & Social Policy. - : Routledge. - 0895-9420 .- 1545-0821.
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Journal article (peer-reviewed)abstract
- Two-thirds of people living with Alzheimer’s disease and related dementias (ADRD) live in low- and middle-income countries, and this figure is expected to rise as these populations are rapidly aging. Since evidence demonstrates links between socioeconomic status and slower rates of cognitive decline, protecting older adults’ cognitive function in resource-limited countries that lack the infrastructure to cope with ADRD is crucial to reduce the burden it places on these populations and their health systems. While cash transfers are a promising intervention to promote healthy cognitive aging, factors such as household wealth and level of education often confound the ability to make causal inferences on the impact of cash transfers and cognitive function. This study uses a quasi-experimental design, leveraging an exogenous expansion to the Old Age Pension for men in South Africa, to approximate causal associations with cognitive function. We found evidence that there is a potential benefit of cash transfers at an earlier age for older individuals. As such, transfers such as pensions or other forms of direct basic income transfers may hold promise as potential interventions to promote healthy cognitive aging.
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| 5. |
- Rosenberg, Molly, et al.
(author)
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The impact of a randomized cash transfer intervention on mortality of adult household members in rural South Africa, 2011–2022
- 2023
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In: Social Science and Medicine. - : Elsevier. - 0277-9536 .- 1873-5347. ; 324
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Journal article (peer-reviewed)abstract
- Background: Increasing socioeconomic resources through cash transfer payments could help promote healthy longevity. However, research in this area is limited due to endogeneity in cash transfer exposures and limited geographic representation.Methods: We leveraged the HPTN 068 randomized cash transfer trial, conducted from 2011 to 2015 in a rural setting in South Africa. We assessed long-term mortality follow-up (until March 2022) on older adult members (n = 3568) of households enrolled in the trial from the complete Agincourt Health and socio-Demographic Surveillance System census of the underlying source population. The trial intervention was a monthly cash payment of 300 Rand conditional on school enrollment of index young women. The payments were split between the young woman (1/3) and their caregiver (2/3). Young women and their households were randomized 1:1 to intervention vs. control. We used Cox PH models to compare mortality rates in older adults living in intervention vs. control households.Findings: The cash transfer intervention did not significantly impact mortality in the full sample [HR (95% CI): 0.94 (0.80, 1.10)]. However, we observed strong protective effects of the cash transfer intervention among those with above-median household assets [HR (95% CI): 0.66 (0.50, 0.86)] and higher educational attainment [HR (95% CI): 0.37 (0.15, 0.93)].Interpretation: Our findings indicate that short-term cash transfers can lead to reduced mortality in certain subgroups of older adults with higher baseline socioeconomic status. Future work should focus on understanding the optimal timing, structure, and targets to maximize the benefits of cash transfer programs in promoting healthy aging and longevity.
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| 6. |
- Österholm, Pär, 1974-
(author)
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Time Series and Macroeconomics: Studies in Demography and Monetary Policy
- 2004
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Doctoral thesis (other academic/artistic)abstract
- Chapter 1 provides a brief introduction to the topics of the thesis and summarises the main results.Chapter 2 studies the econometric properties of the Taylor (1993) rule when applied to U.S., Australian and Swedish data in order to judge its empirical relevance. Unit root tests indicate that the variables commonly used in such modelling are likely to be integrated of order one or near integrated. Given these time series properties, cointegration becomes a necessary condition both for consistent estimation of the parameters of the model and compatibility between the model and the data. Tests find little support for cointegration and, together with an out-of-sample forecast exercise, suggest that we should have serious doubts about the Taylor rule as a reasonable description of how monetary policy is conducted in the countries considered in this study.Chapter 3 investigates the relationship between age structure and GDP in 20 OECD countries using annual data between 1970 and 1999. Using new methodology, the relationship between the variables can be formulated in levels despite the presence of unit roots in the time series. Applying two panel cointegration tests proposed by Pedroni (1999), support is found for a long run relationship between GDP and the number of people in five different age groups. Coefficient estimates from panel regressions support effects predicted by the life cycle hypothesis and human capital theory.Chapter 4 investigates the small sample performance of four well-known cointegration tests when a system has been misspecified by leaving out one relevant variable from a system with one cointegrating vector. In a Monte Carlo study, the size distortions of the Augmented Engle-Granger (Engle and Granger, 1987), Johansen’s (1988) maximum eigenvalue, Johansen’s (1991) trace and the Boswijk (1989) Wald tests are examined. The Johansen trace test adjusted by a finite sample correction is found to have the most robust performance when lag length in the test equations is chosen according to traditional information criteria.Chapter 5 tests for the presence of unit roots in four U.S. macroeconomic time series using panel unit root tests. This is done by introducing a new panel setting which allows the researcher to test several hypotheses for one country instead of one hypothesis for several countries, which has been the standard approach in previous work. The Im, Pesaran and Shin (2003) test, the Multivariate Augmented Dickey-Fuller test (Taylor and Sarno, 1998) and the Johansen (1988) likelihood ratio test are applied to unemployment, the real exchange rate, the nominal interest rate and inflation. The three tests all have ways of controlling the obvious cross-sectional dependence in the panel. Using monthly data from 1960 to 2002 there is evidence that all time series are generated by stationary processes.
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