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Non-surface mass balance is non-negligible for glaciers in Iceland. Several Icelandic glaciers are in the neo-volcanic zone where a combination of geothermal activity, volcanic eruptions and geothermal heat flux much higher than the global average lead to basal melting close to 150 mm w.e. a−1 for the Mýrdalsjökull ice cap and 75 mm w.e. a−1 for the largest ice cap, Vatnajökull. Energy dissipation in the flow of water and ice is also rather large for the high-precipitation, temperate glaciers of Iceland resulting in internal and basal melting of 20–150 mm w.e. a−1. The total non-surface melting of glaciers in Iceland in 1995–2019 was 45–375 mm w.e. a−1 on average for the main ice caps, and was largest for Mýrdalsjökull, the south side of Vatnajökull and Eyjafjallajökull. Geothermal melting, volcanic eruptions and the energy dissipation in the flow of water and ice, as well as calving, all contribute, and thus these components should be considered in mass-balance studies. For comparison, the average mass balance of glaciers in Iceland since 1995 is −500 to −1500 mm w.e. a−1. The non-surface mass balance corresponds to a total runoff contribution of 2.1 km3 a−1 of water from Iceland.
Approximately half of the variation in wellbeing measures overlaps with variation in personality traits. Studies of non-human primate pedigrees and human twins suggest that this is due to common genetic influences. We tested whether personality polygenic scores for the NEO Five-Factor Inventory (NEO-FFI) domains and for item response theory (IRT) derived extraversion and neuroticism scores predict variance in wellbeing measures. Polygenic scores were based on published genome-wide association (GWA) results in over 17,000 individuals for the NEO-FFI and in over 63,000 for the IRT extraversion and neuroticism traits. The NEO-FFI polygenic scores were used to predict life satisfaction in 7 cohorts, positive affect in 12 cohorts, and general wellbeing in 1 cohort (maximal N = 46,508). Meta-analysis of these results showed no significant association between NEO-FFI personality polygenic scores and the wellbeing measures. IRT extraversion and neuroticism polygenic scores were used to predict life satisfaction and positive affect in almost 37,000 individuals from UK Biobank. Significant positive associations (effect sizes <0.05%) were observed between the extraversion polygenic score and wellbeing measures, and a negative association was observed between the polygenic neuroticism score and life satisfaction. Furthermore, using GWA data, genetic correlations of -0.49 and -0.55 were estimated between neuroticism with life satisfaction and positive affect, respectively. The moderate genetic correlation between neuroticism and wellbeing is in line with twin research showing that genetic influences on wellbeing are also shared with other independent personality domains.
This article analyzes a rich Swedish data set with information on the electoral turnout of a large sample of adoptees, their siblings, their adoptive parents, and their biological parents. We use a simple regression framework to decompose the parent-child resemblance in voting into pre-birth factors, measured by biological parents’ voting, and post-birth factors, measured by adoptive parents’ voting. Adoptees are more likely to vote if their biological parents were voters and if they were assigned to families in which the adoptive parents vote. We find evidence of interactions between the pre- and post-birth factors: the effect of the post-birth environment on turnout is greater amongst adoptees whose biological mothers are nonvoters. We also show that the relationships between parental characteristics, such as education, and child turnout, persist even in the absence of a genetic link between parent and child. The regression-based framework we utilize provides a basis for the integration of behavior-genetic research into mainstream political science.
The Swedish Twin Registry (STR) today contains more than 194,000 twins and more than 75,000 pairs have zygosity determined by an intra-pair similarity algorithm, DNA, or by being of opposite sex. Of these, approximately 20,000, 25,000, and 30,000 pairs are monozygotic, same-sex dizygotic, and opposite-sex dizygotic pairs, respectively. Since its establishment in the late 1950s, the STR has been an important epidemiological resource for the study of genetic and environmental influences on a multitude of traits, behaviors, and diseases. Following large investments in the collection of biological specimens in the past 10 years we have now established a Swedish twin biobank with DNA from 45,000 twins and blood serum from 15,000 twins, which effectively has also transformed the registry into a powerful resource for molecular studies. We here describe the main projects within which the new collections of both biological samples as well as phenotypic measures have been collected. Coverage by year of birth, zygosity determination, ethnic heterogeneity, and influences of in vitro fertilization are also described.
Recent studies have shown that trusting attitudes and behavior are biologically influenced. Focusing on the classic trust game, it has been demonstrated that oxytocin increases trust and that humans are endowed with genetic variation that influences their behavior in the game. Moreover, several studies have shown that a large share of the variation in survey responses to trust items is accounted for by an additive genetic component. Against this backdrop, this article makes two important contributions. First, utilizing a unique sample of more than 2,000 complete Swedish twin pairs, we provide further evidence of the heritability of social trust. Our estimates of the additive genetic component in social trust were consistent across the sexes – .33 for males and .39 for females – and are similar to the results reported in earlier studies. Secondly, we show that social trust is phenotypically related to three psychological traits – extraversion, personal control, and intelligence – and that genetic factors account for most of these correlations. Jointly, these psychological factors share around 30% of the genetic influence on social trust both for males and females. Future studies should further explore the possible causal pathways between genes and trust using panel data on both psychological traits and social trust.
A computer simulation model shows that the cost-effectiveness of treating hypertension is highly sensitive to different assumptions about the effectiveness of treatment, the outcome measure, the cost concept, the discounting of effects, and the duration of therapy. Cost-effectiveness analysis should be supplemented by another approach–cost-benefit analysis based on the contingent valuation (CV) method (the measurement, by survey, of willingness to pay). The CV method is tested in two empirical applications that indicate that it is possible to use the method in this area. Its results should be interpreted with caution, however, since the reliability and validity of the method is not yet established.
A controversial issue in cost-effectiveness analysis is the discounting of gained life-years. What has not been realized, however, is that the different methods used for discounting this measurement provide fundamentally different results. The method used is seldom explicitly stated. In the present article the four main methods for the discounting of gained life-years are reviewed and compared. The conclusion is that if we wish to continue comparing results, researchers must employ the same methodology.
This paper investigates the theoretical properties of healthy-years equivalents (HYEs) and quality-adjusted life-years (QALYs). A distinction is made between ex ante HYEs (EA-HYEs) and expected HYEs (EXP-HYEs) and between risk-neutral quality-adjusted life-years (RN-QALYs) and risk-adjusted quality adjusted life-years (RA-QALYs). In the case of certainty, HYEs always rank health profiles according to individual preferences, whereas QALYs only rank health profiles according to individual preferences if constant proportional trade-off holds for all health states and if additive independence of quality in different periods holds. In the case of uncertainty, EA-HYEs always rank risky health profiles the same way as expected utility. The assumptions needed for the other measures to rank risky health profiles the same way as expected utility are: risk neutrality with respect to healthy time for EXP-HYEs; risk neutrality with respect to time in all health states and additive independence of quality in different periods for RN-HYEs; and constant proportional risk posture with respect to time in all health states and additive independence of quality in different periods for RA-QALYs.
How to obtain confidence intervals for cost-effectiveness ratios is complicated by the statistical problems of obtaining a confidence interval for a ratio of random variables. Different approaches have been suggested in the literature, but no consensus has been reached. We propose an alternative simple solution to this problem. By multiplying the effectiveness units by the price per effectiveness unit, both costs and benefits can be expressed in monetary terms and standard statistical techniques can be used to estimate a confidence interval for net benefits. This approach avoids the ratio estimation problem and explicitly recognizes that the price per effectiveness unit has to be known to provide cost-effectiveness analysis with a useful decision rule.
The costs included in economic evaluations of health care vary from study to study. Based on the theory of cost-benefit analysis, the costs that should be included in an economic evaluation are those not already included in the measurement of willingness to pay (net willingness to pay above any treatment costs paid by the individual) in a cost-benefit analysis or in the easurement of effectiveness in a cost-effectiveness analysis. These costs can be defined as the onsumption externality of the treatment (the change in production minus consumption for those included in the treatment program). For a full economic evaluation, the consequences for those included in the treatment program and a caring externality (altruism) should also be added.
This paper gives a detailed presentation of a computer model for evaluating
the cost-effectiveness (CE) of hormone replacement therapy (HRT), describing
the model's design, structure, and data requirements. The model needs
data specified for costs, quality of life, risks, and mortality rates. As an
illustration, the CE of HRT in Sweden is calculated. Two treatment strategies
are evaluated for asymptomatic women: estrogen-only therapy and estrogen
combined with a progestin. The model produces similar results compared with
earlier studies. The CE ratios improve with the size of the risk reduction and
generally with age. Further, estrogen-only therapy is associated with a lower
cost per gained effectiveness unit compared with combined therapy. Uncertainty
surrounding the long-term effects of HRT means that the CE estimates should be
interpreted carefully. The model permits the inclusion of indirect costs and
costs in added life-years, allowing the analysis to be made from a societal
perspective, which is an improvement relative to previous studies.