| 1. |
- Patterson, Nick, et al.
(author)
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Large-scale migration into Britain during the Middle to Late Bronze Age
- 2022
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In: Nature. - : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; , s. 588-594
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Journal article (peer-reviewed)abstract
- Present-day people from England and Wales harbour more ancestry derived from Early European Farmers (EEF) than people of the Early Bronze Age1. To understand this, we generated genome-wide data from 793 individuals, increasing data from the Middle to Late Bronze and Iron Age in Britain by 12-fold, and Western and Central Europe by 3.5-fold. Between 1000 and 875 BC, EEF ancestry increased in southern Britain (England and Wales) but not northern Britain (Scotland) due to incorporation of migrants who arrived at this time and over previous centuries, and who were genetically most similar to ancient individuals from France. These migrants contributed about half the ancestry of Iron Age people of England and Wales, thereby creating a plausible vector for the spread of early Celtic languages into Britain. These patterns are part of a broader trend of EEF ancestry becoming more similar across central and western Europe in the Middle to Late Bronze Age, coincident with archaeological evidence of intensified cultural exchange2-6. There was comparatively less gene flow from continental Europe during the Iron Age, and Britain's independent genetic trajectory is also reflected in the rise of the allele conferring lactase persistence to ~50% by this time compared to ~7% in central Europe where it rose rapidly in frequency only a millennium later. This suggests that dairy products were used in qualitatively different ways in Britain and in central Europe over this period.
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| 2. |
- Delrez, Laetitia, et al.
(author)
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Transit detection of the long-period volatile-rich super-Earth nu(2) Lupi d with CHEOPS
- 2021
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In: Nature Astronomy. - : Springer Science and Business Media LLC. - 2397-3366. ; :5, s. 775-787
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Journal article (peer-reviewed)abstract
- Exoplanets transiting bright nearby stars are key objects for advancing our knowledge of planetary formation and evolution. The wealth of photons from the host star gives detailed access to the atmospheric, interior and orbital properties of the planetary companions. nu(2) Lupi (HD 136352) is a naked-eye (V = 5.78) Sun-like star that was discovered to host three low-mass planets with orbital periods of 11.6, 27.6 and 107.6 d via radial-velocity monitoring(1). The two inner planets (b and c) were recently found to transit(2), prompting a photometric follow-up by the brand new Characterising Exoplanets Satellite (CHEOPS). Here, we report that the outer planet d is also transiting, and measure its radius and mass to be 2.56 +/- 0.09 R-circle plus and 8.82 +/- 0.94 M-circle plus, respectively. With its bright Sun-like star, long period and mild irradiation (similar to 5.7 times the irradiation of Earth), nu(2) Lupi d unlocks a completely new region in the parameter space of exoplanets amenable to detailed characterization. We refine the properties of all three planets: planet b probably has a rocky mostly dry composition, while planets c and d seem to have retained small hydrogen-helium envelopes and a possibly large water fraction. This diversity of planetary compositions makes the nu(2) Lupi system an excellent laboratory for testing formation and evolution models of low-mass planets.
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| 3. |
- Hjalmarsson, Erik, 1975, et al.
(author)
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Dividend Growth Does Not Help Predict Returns Compared To Likelihood-Based Tests: An Anatomy of the Dog
- 2021
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In: Critical Finance Review. - : Now Publishers. - 2164-5744 .- 2164-5760. ; 10:3, s. 445-464
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Journal article (peer-reviewed)abstract
- The dividend-growth based test of return predictability, proposed by Cochrane (2008), is similar to a likelihood-based test of the standard return-predictability model, treating the autoregressive (AR) parameter of the dividend-price ratio as known. In comparison to standard OLS-based inference, both tests can achieve power gains by using restrictions or prior information on the value of the AR parameter. When compared to the likelihood-based test, there are no power advantages for the dividend-growth based test. In common implementations, with the AR parameter set equal to the corresponding OLS estimate, Cochrane's test suffers from severe size distortions.
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| 4. |
- Hjalmarsson, Erik, 1975, et al.
(author)
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Long-run predictability tests are even worse than you thought
- 2022
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In: Journal of Applied Econometrics. - : Wiley. - 0883-7252 .- 1099-1255. ; 37:7, s. 1334-1355
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Journal article (peer-reviewed)abstract
- We derive asymptotic results for the long-horizon ordinary least squares (OLS) estimator and corresponding t$$ t $$-statistic for stationary autoregressive predictors. The t$$ t $$-statistic-formed using the correct asymptotic variance-together with standard-normal critical values result in a correctly-sized test for exogenous predictors. For endogenous predictors, the test is size distorted regardless of the persistence in the predictor and adjusted critical values are necessary. The endogeneity problem stems from the long-run estimation and is distinct from the ordinary persistence-dependent "Stambaugh" bias. The bias for fully stationary predictors appears not to have been previously noted and adds further difficulty to inference in long-run predictive regressions.
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| 5. |
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| 6. |
- Hjalmarsson, Erik, 1975, et al.
(author)
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Testing Return Predictability with the Dividend-Growth Equation: An Anatomy of the Dog
- 2019
-
Reports (other academic/artistic)abstract
- The dividend-growth based test of return predictability, proposed by Cochrane [2008, Review of Financial Studies 21, 1533-1575], is similar to a likelihood-based test of the standard return-predictability model, treating the autoregressive parameter of the dividend-price ratio as known. In comparison to standard OLS-based inference, both tests achieve power gains from a strong use of the exact value pos- tulated for the autoregressive parameter. When compared to the likelihood-based test, there are no power advantages for the dividend-growth based test. In common implementations, with the autoregressive parameter set equal to the corresponding OLS estimate, Cochrane's test also suffers from severe size distortions.
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| 7. |
- Javed, Farrukh, 1984-, et al.
(author)
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Performance analysis of nowcasting of GDP growth when allowing for conditional heteroscedasticity and non-Gaussianity
- 2022
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In: Applied Economics. - : Routledge. - 0003-6846 .- 1466-4283. ; 54:58, s. 6669-6686
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Journal article (peer-reviewed)abstract
- The nowcasting performance of autoregressive models for GDP growth are analysed in a setting where the error term is allowed to be characterized both by conditional heteroscedasticity and non-Gaussianity. Standard, publicly available, quarterly data on GDP growth from 1979 to 2019 for six countries are employed: Australia, Canada, France, Japan, the United Kingdom and the United States. In-sample analysis suggests that when homoscedasticity is assumed, support is provided for non-Gaussian error terms; the estimated degrees of freedom of the t-distribution lie between two and seven for all countries. However, allowing for both conditional heteroscedasticity and t-distributed innovations, results indicate that conditional heteroscedasticity captures the fat-tailed behaviour of the data to a large extent. Results from out-of-sample analysis show that point nowcasts are hardly affected by taking conditional heteroscedasticity and/or non-Gaussianity into account. For the density nowcasts, it is found that accounting for conditional heteroscedasticity leads to improvements for Australia, Canada, Japan, the United Kingdom and the United States; allowing for non-Gaussianity seems less important though. This result is robust to which measure is used for assessing density nowcasting performance.
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| 8. |
- Karlsson, Sune, Professor, 1960-, et al.
(author)
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Svensk ekonomi är inte normal (och oberoende) – fakta om makroekonomiska variablers tidsserieegenskaper
- 2023
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In: Ekonomisk Debatt. - Stockholm : Nationalekonomiska föreningen. - 0345-2646. ; 51:1, s. 42-54
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Journal article (peer-reviewed)abstract
- Att de störningar som drabbar makroekonomin är normalfördelade och har konstant varians är två antaganden som allt oftare har övergivits i den inter-nationella forskningslitteraturen under de senaste två decennierna. I denna artikel undersöks om detta är relevant för ett antal nyckelvariabler i svensk mak-roekonomi. Sammantaget tyder våra resultat på att forskare och policyekonomer som modellerar svenska makroekonomiska variabler – t ex i syfte att beskriva riskbilden kring dem – har påtaglig anledning att åtminstone överge antagandet om konstant störningsvarians. Ett konkret problem som annars kan uppstå är att prognososäkerhet överskattas i lugna tider och underskattas i turbulenta tider.
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| 9. |
- Kiss, Anita, et al.
(author)
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Synthesis of novel 17-triazolyl-androst-5-en-3-ol epimers via Cu(I)-catalyzed azide-alkyne cycloaddition and their inhibitory effect on 17 alpha-hydroxylase/ C-17,C-20-lyase
- 2018
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In: Steroids. - : Elsevier BV. - 0039-128X .- 1878-5867. ; 135, s. 79-91
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Journal article (peer-reviewed)abstract
- The regioselective Cu(I)-catalyzed 1,3-dipolar cycloaddition of 17 alpha- and 17 beta-azidoandrost-5-en-3 beta-ol epimers (3b and 5b) with different terminal alkynes afforded novel 1,4-substituted triazolyl derivatives (8a-k and 9a-k). For the preparation of 5'-iodo-l',2',3'-triazoles (8m-n and 9m-n), an improved method was developed, directly from steroidal azides and terminal alkynes, in reaction mediated by Cul and IC1 as iodinating agents. Acetolysis and subsequent hydrolysis of 8n and 9n yielded 5'-hydroxy-l',2',3'-triazoles 8o and 9o. The inhibitory effect of 8a-o, 9a-o, 3, and 5 on rat testicular C-17,C-20-lyase was investigated by means of an in vitro radioincubation technique. The results revealed that the C-17 epimers of steroidal triazoles influence the C-17,C-20-lyase effect. Inhibitors were found only in the 17 alpha-triazolyl series (8a-o), whereas in the C-17 azide pair the 17 beta compound (5b) was more potent.
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| 10. |
- Kiss, Tamás, 1988-, et al.
(author)
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Corona, Crisis and Conditional Heteroscedasticity
- 2021
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In: Applied Economics Letters. - : Routledge. - 1350-4851 .- 1466-4291. ; 28:9, s. 755-759
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Journal article (peer-reviewed)abstract
- In this paper, we illustrate the macroeconomic risk associated with the early stage of the corona- virus outbreak. Using monthly data ranging from July 1991 to March 2020 on a recently developed coincidence indicator of global output growth, we estimate an autoregressive model with GARCH effects and non-Gaussian disturbances. Our results indicate that i) accounting for conditional heteroscedasticity is important and ii) risk, measured as the volatility of the shocks to the process, is at a very high level – largely on par with that experienced around the financial crisis of 2008–2009.
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