| 1. |
- Pedersen, Nancy L., et al.
(författare)
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IGEMS : The Consortium on Interplay of Genes and Environment Across Multiple Studies - An Update
- 2019
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Ingår i: Twin Research and Human Genetics. - : Cambridge University Press. - 1832-4274 .- 1839-2628. ; 22:6, s. 809-816
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Tidskriftsartikel (refereegranskat)abstract
- The Interplay of Genes and Environment across Multiple Studies (IGEMS) is a consortium of 18 twin studies from 5 different countries (Sweden, Denmark, Finland, United States, and Australia) established to explore the nature of gene-environment (GE) interplay in functioning across the adult lifespan. Fifteen of the studies are longitudinal, with follow-up as long as 59 years after baseline. The combined data from over 76,000 participants aged 14-103 at intake (including over 10,000 monozygotic and over 17,000 dizygotic twin pairs) support two primary research emphases: (1) investigation of models of GE interplay of early life adversity, and social factors at micro and macro environmental levels and with diverse outcomes, including mortality, physical functioning and psychological functioning; and (2) improved understanding of risk and protective factors for dementia by incorporating unmeasured and measured genetic factors with a wide range of exposures measured in young adulthood, midlife and later life.
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| 2. |
- Abdulbaqi, Dana M., et al.
(författare)
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Enhanced Oil Recovery (EOR) as a Stepping Stone to Carbon Capture and Sequestration (CCS)
- 2018
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Ingår i: Mineral Economics. - : Springer. - 2191-2203 .- 2191-2211. ; 31:1-2, s. 239-251
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Tidskriftsartikel (refereegranskat)abstract
- Environmental concerns about carbon emissions coupled with the oil industry’s need to secure additional CO2 for enhanced oil recovery (CO2-EOR) projects have sparked interest in the potential that CO2-EOR may have in jumpstarting carbon capture and sequestration (CCS). However, existing studies on the viability of coupling CO2-EOR with CCS have generally placed more focus on either the engineering or economic aspects of the problem. Most engineering studies focus on the technical aspects of the CO2-EOR project to produce the maximum amount of oil, while simultaneously storing the most CO2 during the production process with the economics as an afterthought, while most economic studies found have focused on a singular aspect of the issue such as impacts of exogenously varying injection rates. Furthermore, modelling efforts have stopped at the end of the productive life of the field. We build a unique two-stage dynamic optimization model, which simultaneously addresses engineering and economic policy aspects, to study the viability of coupling CO2-EOR transitioning into CCS. Our model includes a carbon tax for emissions, which becomes a subsidy for full scale sequestration after oil production has ceased; this allows us to explore the transition from CO2-EOR, our first stage, to sole CO2 sequestration in our second stage for a single field. We maximize the operator’s profits across both stages, while tracking the responsiveness of oil production and total carbon movements to both price and policy changes. We pair our optimization model with a reservoir simulation model, allowing us to mimic actual field behavior, giving our work a more realistic representation of both production and sequestration profiles. Our results suggest that small increases in the level of carbon tax can have large and discontinuous impacts on net sequestration. This stems from the observed transition from limited natural sources of CO2 to more expensive captured CO2 resulting from the implemented policy. With appropriate taxes, total volumes of captured CO2 sequestered across both stages are equivalent to 30 to 40% of the emissions from the use of the oil produced. With the credits oil producers receive from sequestering CO2, which equate to the tax, relatively high carbon taxes incentivize additional sequestration without significantly impacting the supply of oil. This, alongside maintaining a steady stream of profits, is a win-win situation for energy security and the climate.
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| 3. |
- Akimaya, Muhammad, et al.
(författare)
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Estimating the Cross-Price Elasticity of Regular Gasoline with Respect to the Price of Premium Gasoline
- 2018
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Ingår i: Journal of Transport Economics and Policy. - : University of Bath. - 0022-5258 .- 1754-5951. ; 52:2, s. 157-180
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Tidskriftsartikel (refereegranskat)abstract
- Gasoline demand has been extensively researched, yet there has been no attempt to estimate cross-price elasticities of different grades of gasoline. Such knowledge will allow accurate determination of the impact of a fuel pricing policy that has different rates of tax or subsidy depending on the gasoline grade. Using monthly data on the Mexican gasoline market from 1999 to 2014, regular gasoline demand is estimated with an ARDL model. Endogeneity of the price and structural break are also investigated. The cross-price elasticity between regular and premium gasoline is found to be 0.875, confirming high substitutability among gasoline with different grades.
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| 4. |
- Akimaya, Muhammad, et al.
(författare)
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Simulation of price controls for different grade of gasoline : The case of Indonesia
- 2017
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Ingår i: Energy Economics. - : Elsevier. - 0140-9883 .- 1873-6181. ; 68, s. 373-382
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Tidskriftsartikel (refereegranskat)abstract
- A gasoline subsidy is one of the most prevalent strategies for distributing welfare to the people in oil-producing countries. However well-intentioned, the policy will distort the gasoline market with the resulting inefficiencies. Furthermore, the gasoline subsidy takes a great amount of government's budget. Arguably, these funds could be spent elsewhere with a greater impact on economic growth. These governments are aware of the cost of such a policy, yet face difficulties in removing the policy because of strong resistance from the public. This paper looks at the unique case of Indonesia that only provides a subsidy for regular gasoline and in turn proposes an alternative policy that introduces a subsidy for premium gasoline at a lower rate to reduce the overall gasoline subsidy cost. There has yet to be any research that simulates price controls for gasoline with different grades. The aggregate demand for gasoline in Indonesia is replicated using a translog cost calibration approach. Simulations based on the calibrated demand are then performed and the results confirm the existence of potential savings that are largely determined by the cross-price elasticities between regular and premium gasoline. The benchmark scenario, based on a recent study of substitutability between gasoline by grades, results in an 11.5% reduction in subsidy cost of around 950 million USD with a subsidy rate of Rp 2254/liter. Furthermore, the optimal rate of subsidy for premium gasoline results in a reduction of inefficiency as consumers' welfare increase by 6.8 trillion rupiahs (or 560 million USD).
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| 5. |
- Bai, Yang, et al.
(författare)
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Evaluating the Management of U.S. Strategic Petroleum Reserve during Oil disruptions
- 2018
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Ingår i: Energy Policy. - : Elsevier. - 0301-4215 .- 1873-6777. ; 117, s. 25-38
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Tidskriftsartikel (refereegranskat)abstract
- Numerous countries have set up strategic petroleum reserves (SPRs) in response to oil disruptions since 1970. While numerous studies model such programs, we found few that evaluate SPRs' historical performance. Thus, we evaluate the U.S. SPR's performance by comparing actual real costs with estimated real benefits. From 1976 to 2014, the real U.S. SPR cost was about $219 billion real (2014$) dollars, whereas the real benefit was only $122 billion. Sensitivity testing suggests such negative net benefits are qualitatively robust. However, if world oil demand is extremely inelastic to oil price or GDP is elastic enough to oil price shocks, the estimated U.S. SPR net benefit is positive. Sensitivity testing around total real costs and benefits range from $380 billion to $80 billion. Limited testing of IEA coordinated drawdowns suggests that total U.S. benefits jump from $122 billion to more than $400 billion putting the SPR strongly in the black. Limited testing of private sector inventory changes was more disappointing and tentatively suggests private activities may at times have offset some of the government drawdowns. With 20-20 hindsight, initial experimentation found that better management could have significantly enhanced the value of the U.S. SPR, especially for the 1990-91 disruption.
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| 6. |
- Jelenkovic, Aline, et al.
(författare)
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Zygosity Differences in Height and Body Mass Index of Twins From Infancy to Old Age : A Study of the CODATwins Project
- 2015
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Ingår i: Twin Research and Human Genetics. - : Cambridge University Press. - 1832-4274 .- 1839-2628. ; 18:5, s. 557-570
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Tidskriftsartikel (refereegranskat)abstract
- A trend toward greater body size in dizygotic (DZ) than in monozygotic (MZ) twins has been suggested by some but not all studies, and this difference may also vary by age. We analyzed zygosity differences in mean values and variances of height and body mass index (BMI) among male and female twins from infancy to old age. Data were derived from an international database of 54 twin cohorts participating in the COllaborative project of Development of Anthropometrical measures in Twins (CODATwins), and included 842,951 height and BMI measurements from twins aged 1 to 102 years. The results showed that DZ twins were consistently taller than MZ twins, with differences of up to 2.0 cm in childhood and adolescence and up to 0.9 cm in adulthood. Similarly, a greater mean BMI of up to 0.3 kg/m(2) in childhood and adolescence and up to 0.2 kg/m(2) in adulthood was observed in DZ twins, although the pattern was less consistent. DZ twins presented up to 1.7% greater height and 1.9% greater BMI than MZ twins; these percentage differences were largest in middle and late childhood and decreased with age in both sexes. The variance of height was similar in MZ and DZ twins at most ages. In contrast, the variance of BMI was significantly higher in DZ than in MZ twins, particularly in childhood. In conclusion, DZ twins were generally taller and had greater BMI than MZ twins, but the differences decreased with age in both sexes.
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| 7. |
- Nothhaft, Howard, et al.
(författare)
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Editors’ Introduction
- 2018
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Ingår i: International Journal of Strategic Communication. - Heidelberg : International Association for Energy Economics. - 1553-118X. ; 39:1, s. 257-, s. 7-16, s. 1-6
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Tidskriftsartikel (refereegranskat)
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| 8. |
- Pahlen, Shandell, et al.
(författare)
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Age-moderation of genetic and environmental contributions to cognitive functioning in mid- and late-life for specific cognitive abilities
- 2018
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Ingår i: Intelligence. - : Elsevier. - 0160-2896 .- 1873-7935. ; 68, s. 70-81
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Tidskriftsartikel (refereegranskat)abstract
- Age moderation of genetic and environmental contributions to Digits Forward, Digits Backward, Block Design, Symbol Digit, Vocabulary, and Synonyms was investigated in a sample of 14,534 twins aged 26 to 98 years. The Interplay of Genes and Environment across Multiple Studies (IGEMS) consortium contributed the sample, which represents nine studies from three countries (USA, Denmark, and Sweden). Average test performance was lower in successively older age groups for all tests. Significant age moderation of additive genetic, shared environmental, and non-shared environmental variance components was observed, but the pattern varied by test. The genetic contribution to phenotypic variance across age was smaller for both Digit Span tests, greater for Synonyms, and stable for Block Design and Symbol Digit. The non-shared environmental contribution was greater with age for the Digit Span tests and Block Design, while the shared environmental component was small for all tests, often more so with age. Vocabulary showed similar age-moderation patterns as Synonyms, but these effects were nonsignificant. Findings are discussed in the context of theories of cognitive aging.
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| 9. |
- Silventoinen, Karri, et al.
(författare)
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Education in twins and their parents across birth cohorts over 100 years : an individual-level pooled analysis of 42 twin cohorts
- 2017
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Ingår i: Twin Research and Human Genetics. - Stockholm : Karolinska Institutet, Dept of Medical Epidemiology and Biostatistics. - 1832-4274 .- 1839-2628.
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Tidskriftsartikel (refereegranskat)abstract
- Whether monozygotic (MZ) and dizygotic (DZ) twins differ from each other in a variety of phenotypes is important for genetic twin modeling and for inferences made from twin studies in general. We analyzed whether there were differences in individual, maternal and paternal education between MZ and DZ twins in a large pooled dataset. Information was gathered on individual education for 218,362 adult twins from 27 twin cohorts (53% females; 39% MZ twins), and on maternal and paternal education for 147,315 and 143,056 twins respectively, from 28 twin cohorts (52% females; 38% MZ twins). Together, we had information on individual or parental education from 42 twin cohorts representing 19 countries. The original education classifications were transformed to education years and analyzed using linear regression models. Overall, MZ males had 0.26 (95% CI [0.21, 0.31]) years and MZ females 0.17 (95% CI [0.12, 0.21]) years longer education than DZ twins. The zygosity difference became smaller in more recent birth cohorts for both males and females. Parental education was somewhat longer for fathers of DZ twins in cohorts born in 1990-1999 (0.16 years, 95% CI [0.08, 0.25]) and 2000 or later (0.11 years, 95% CI [0.00, 0.22]), compared with fathers of MZ twins. The results show that the years of both individual and parental education are largely similar in MZ and DZ twins. We suggest that the socio-economic differences between MZ and DZ twins are so small that inferences based upon genetic modeling of twin data are not affected.
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| 10. |
- Silventoinen, Karri, et al.
(författare)
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The CODATwins Project : The Cohort Description of Collaborative Project of Development of Anthropometrical Measures in Twins to Study Macro-Environmental Variation in Genetic and Environmental Effects on Anthropometric Traits
- 2015
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Ingår i: Twin Research and Human Genetics. - : Cambridge University Press. - 1832-4274 .- 1839-2628. ; 18:4
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Tidskriftsartikel (refereegranskat)abstract
- For over 100 years, the genetics of human anthropometric traits has attracted scientific interest. In particular, height and body mass index (BMI, calculated as kg/m2) have been under intensive genetic research. However, it is still largely unknown whether and how heritability estimates vary between human populations. Opportunities to address this question have increased recently because of the establishment of many new twin cohorts and the increasing accumulation of data in established twin cohorts. We started a new research project to analyze systematically (1) the variation of heritability estimates of height, BMI and their trajectories over the life course between birth cohorts, ethnicities and countries, and (2) to study the effects of birth-related factors, education and smoking on these anthropometric traits and whether these effects vary between twin cohorts. We identified 67 twin projects, including both monozygotic (MZ) and dizygotic (DZ) twins, using various sources. We asked for individual level data on height and weight including repeated measurements, birth related traits, background variables, education and smoking. By the end of 2014, 48 projects participated. Together, we have 893,458 height and weight measures (52% females) from 434,723 twin individuals, including 201,192 complete twin pairs (40% monozygotic, 40% same-sex dizygotic and 20% opposite-sex dizygotic) representing 22 countries. This project demonstrates that large-scale international twin studies are feasible and can promote the use of existing data for novel research purposes.
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| 11. |
- Wang, Sheng, et al.
(författare)
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De Novo Sequence and Copy Number Variants Are Strongly Associated with Tourette Disorder and Implicate Cell Polarity in Pathogenesis
- 2018
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Ingår i: Cell Reports. - : CELL PRESS. - 2211-1247. ; 24:13, s. 3441-
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Tidskriftsartikel (refereegranskat)abstract
- We previously established the contribution of de novo damaging sequence variants to Tourette disorder (TD) through whole-exome sequencing of 511 trios. Here, we sequence an additional 291 TD trios and analyze the combined set of 802 trios. We observe an overrepresentation of de novo damaging variants in simplex, but not multiplex, families; we identify a high-confidence TD risk gene, CELSR3 (cadherin EGF LAG seven-pass G-type receptor 3); we find that the genes mutated in TD patients are enriched for those related to cell polarity, suggesting a common pathway underlying pathobiology; and we confirm a statistically significant excess of de novo copy number variants in TD. Finally, we identify significant overlap of de novo sequence variants between TD and obsessive-compulsive disorder and de novo copy number variants between TD and autism spectrum disorder, consistent with shared genetic risk.
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| 12. |
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| 13. |
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