Intelligence is highly heritable and a major determinant of human health and well-being. Recent genome-wide meta-analyses have identified 24 genomic loci linked to variation in intelligence, but much about its genetic underpinnings remains to be discovered. Here, we present a large-scale genetic association study of intelligence (n = 269,867), identifying 205 associated genomic loci (190 new) and 1,016 genes (939 new) via positional mapping, expression quantitative trait locus (eQTL) mapping, chromatin interaction mapping, and gene-based association analysis. We find enrichment of genetic effects in conserved and coding regions and associations with 146 nonsynonymous exonic variants. Associated genes are strongly expressed in the brain, specifically in striatal medium spiny neurons and hippocampal pyramidal neurons. Gene set analyses implicate pathways related to nervous system development and synaptic structure. We confirm previous strong genetic correlations with multiple health-related outcomes, and Mendelian randomization analysis results suggest protective effects of intelligence for Alzheimer's disease and ADHD and bidirectional causation with pleiotropic effects for schizophrenia. These results are a major step forward in understanding the neurobiology of cognitive function as well as genetically related neurological and psychiatric disorders.

ehaviors related to self-regulation, such as substance use disorders or antisocial behaviors, have far-reaching consequences for affected individuals, their families, communities and society at large 1,2 . Collectively, this group of correlated traits are classified as externalizing 3 . Twin studies have demonstrated that externalizing liability is highly heritable (~80%) 4,5 . To date, however, no large-scale molecular genetic studies have utilized the extensive degree of genetic overlap among externalizing traits to aid gene discovery, as most studies have focused on individual disorders 6 . For many high-cost, high-risk behaviors with an externalizing component-opioid use disorder and suicide attempts 7 being salient examples-there are limited genotyped cases available for gene discovery 8,9 .A complementary strategy to the single-disease approach is to study the shared genetic architecture across traits in multivariate analyses, which boosts statistical power by pooling data across

Purpose – The purpose of this study is to identify an appropriate factor structure that may be utilized to effectively measure a hotel’s performance relative to service quality in a mid-scale setting. Customer perceptions of service quality in mid-scale hotels have largely been ignored; the focus of researchers has been the upscale (4-star) and luxury (5-star) segments. Design/methodology/approach – A 27-item questionnaire is utilized to measure service quality with an initial sample size of over 2,500 respondents. Principle component analysis is utilized to determine the factor structure and regression analysis to determine which factors may serve as predictors of a hotel’s ability to meet customers’ expectations and to provide value. Findings – A three-dimensional model emerged from the data, consistent with the theorizing of Rust and Oliver (1994), which includes the service product, service delivery and service environment. The service environment is the strongest predictor of a hotel’s ability to meet guests’ expectations and to provide guests with value within this context, which is inconsistent with findings in upscale and luxury hotels. Research limitations/implications – The generalizability of this research may be challenged, as the study was conducted within the context of an oceanfront resort destination dominated by leisure travelers; however, the study may be replicated in additional settings to determine if a similar bundling of service quality attributes occurs in other mid-scale settings including business hotels, as well as economy hotels. Practical implications – A three-factor model may be more appropriate for assessing service quality in a mid-scale (3-star) environment. In this setting, the service environment and service product may be more important measures of service quality than service delivery. This is an important finding, as many mid-scale and select-service, as well as new mid-scale, lifestyle hotel concepts, attempt to drive profitability by deemphasizing service delivery or by utilizing technology to facilitate service delivery. These findings may also assist operators of mid-scale hotels in improving guests’ perceptions of quality, which has been found to increase perceived value and may positively influence purchase or revisit intentions (Kashyap and Bojanic, 2000). Originality/value – Service quality research has been conducted, almost exclusively, in first-class (4-star) and luxury (5-star) hotels, while the majority of hotels do not fall into these categories. Although guest expectations relative to service quality may be lower in more moderately priced, mid-scale hotels, service quality remains a critical variable that influences a guest’s decision to return or recommend a hotel to others. Many travelers now utilize online reviews to minimize purchase risk by seeking information relative to service quality when selecting a hotel. Consequently, it is more important than ever that service quality is understood in hotels at all service levels. The present research contributes to filling this gap in the literature.

This review offers an update on research conducted with FinnTwin12 (FT12), the youngest of the three Finnish Twin Cohorts. FT12 was designed as a two-stage study. In the first stage, we conducted multiwave questionnaire research enrolling all eligible twins born in Finland during 1983–1987 along with their biological parents. In stage 2, we intensively studied a subset of these twins with in-school assessments at age 12 and semistructured poly-diagnostic interviews at age 14. At baseline, parents of intensively studied twins were administered the adult version of the interview. Laboratory studies with repeat interviews, neuropsychological tests, and collection of DNA were made of intensively studied twins during follow-up in early adulthood. The basic aim of the FT12 study design was to obtain information on individual, familial and school/neighborhood risks for substance use/abuse prior to the onset of regular tobacco and alcohol use and then track trajectories of use and abuse and their consequences into adulthood. But the longitudinal assessments were not narrowly limited to this basic aim, and with multiwave, multirater assessments from ages 11 to 12, the study has created a richly informative data set for analyses of gene–environment interactions of both candidate genes and genomewide measures with measured risk-relevant environments. Because 25 years have elapsed since the start of the study, we are planning a fifth-wave follow-up assessment.

Background and Objectives There have been remarkable advances in understanding genetic influences on complex traits; however, individuals of African descent have been underrepresented in genetic research. Methods We review the limitations of existing genetic research on alcohol phenotypes in African Americans (AA) including both twin and gene identification studies, possible reasons for underrepresentation of AAs in genetic research, the implications of the lack of racially diverse samples, and special considerations regarding conducting genetic research in AA populations. Results There is a marked absence of large-scale AA twin studies so little is known about the genetic epidemiology of alcohol use and problems among AAs. Individuals of African descent have also been underrepresented in gene identification efforts; however, there have been recent efforts to enhance representation. It remains unknown the extent to which genetic variants associated with alcohol use outcomes in individuals of European and African descent will be shared. Efforts to increase representation must be accompanied by careful attention to the ethical, legal, and social implications of genetic research. This is particularly true for AAs due to the history of abuse by the biomedical community and the persistent racial discrimination targeting this population. Conclusions and Scientific Significance Lack of representation in genetic studies limits our understanding of the etiological factors that contribute to substance use and psychiatric outcomes in populations of African descent and has the potential to further perpetuate health disparities. Involving individuals of diverse ancestry in discussions about genetic research will be critical to ensure that all populations benefit equally from genetic advances.