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Mounting evidence showed that insula contributed to the neurobiological mechanism of suicidal behaviors in bipolar disorder (BD). However, no studies have analyzed the dynamic functional connectivity (dFC) of insular Mubregions and its association with personality traits in BD with suicidal behaviors. Therefore, we investigated the alterations of dFC variability in insular subregions and personality characteristics in BD patients with a recent suicide attempt (SA).
Thirty unmedicated BD patients with SA, 38 patients without SA (NSA) and 35 demographically matched healthy controls (HCs) were included. The sliding-window analysis was used to evaluate whole-brain dFC for each insular subregion seed. We assessed between-group differences of psychological characteristics on the Minnesota Multiphasic Personality Inventory-2. Finally, a multivariate regression model was adopted to predict the severity of suicidality.
Compared to NSA and HCs, the SA group exhibited decreased dFC variability values between the left dorsal anterior insula and the left anterior cerebellum. These dFC variability values could also be utilized to predict the severity of suicidality (r = 0.456, p = 0.031), while static functional connectivity values were not appropriate for this prediction. Besides, the SA group scored significantly higher on the schizophrenia clinical scales (p < 0.001) compared with the NSA group.
Our findings indicated that the dysfunction of insula–cerebellum connectivity may underlie the neural basis of SA in BD patients, and highlighted the dFC variability values could be considered a neuromarker for predictive models of the severity of suicidality. Moreover, the psychiatric features may increase the vulnerability of suicidal behavior.
Evidence of couples’ BMI and its influence on birth weight is limited and contradictory. Therefore, this study aims to assess the association between couple’s preconception BMI and the risk of small for gestational age (SGA)/large for gestational age (LGA) infant, among over 4·7 million couples in a retrospective cohort study based on the National Free Pre-pregnancy Checkups Project (NFPCP) between December 1, 2013 and November 30, 2016 in China. Among the live births, 256,718 (5·44%) SGA events and 506,495 (10·73%) LGA events were documented, respectively. After adjusting for confounders, underweight men had significantly higher risk [OR 1·17 95%CI (1·15-1·19)] of SGA infants compared with men with normal BMI, while a significant and increased risk of LGA infants was obtained for overweight and obese men [OR 1·08 (95% CI: 1·06-1·09); OR 1·19 (95%CI 1·17-1·20)] respectively. The restricted cubic spline (RCS) result revealed a non-linearly decreasing dose-response relationship of paternal BMI (less than 22·64) with SGA. Meanwhile, a non-linearly increasing dose-response relationship of paternal BMI (more than 22·92) with LGA infants was observed. Moreover, similar results about the association between maternal preconception BMI and SGA/LGA infants were obtained. Abnormal preconception BMIs in either women or men were associated with increased risk of SGA/LGA infants, respectively. Overall, couple’s abnormal weight before pregnancy may be an important preventable risk factor for SGA/LGA infants.
Previous studies have demonstrated structural and functional changes of the hippocampus in patients with major depressive disorder (MDD). However, no studies have analyzed the dynamic functional connectivity (dFC) of hippocampal subregions in melancholic MDD. We aimed to reveal the patterns for dFC variability in hippocampus subregions – including the bilateral rostral and caudal areas and its associations with cognitive impairment in melancholic MDD.
Forty-two treatment-naive MDD patients with melancholic features and 55 demographically matched healthy controls were included. The sliding-window analysis was used to evaluate whole-brain dFC for each hippocampal subregions seed. We assessed between-group differences in the dFC variability values of each hippocampal subregion in the whole brain and cognitive performance on the MATRICS Consensus Cognitive Battery (MCCB). Finally, association analysis was conducted to investigate their relationships.
Patients with melancholic MDD showed decreased dFC variability between the left rostral hippocampus and left anterior lobe of cerebellum compared with healthy controls (voxel p < 0.005, cluster p < 0.0125, GRF corrected), and poorer cognitive scores in working memory, verbal learning, visual learning, and social cognition (all p < 0.05). Association analysis showed that working memory was positively correlated with the dFC variability values of the left rostral hippocampus-left anterior lobe of the cerebellum (r = 0.338, p = 0.029) in melancholic MDD.
These findings confirmed the distinct dynamic functional pathway of hippocampal subregions in patients with melancholic MDD, and suggested that the dysfunction of hippocampus-cerebellum connectivity may be underlying the neural substrate of working memory impairment in melancholic MDD.
In this paper, we concern with a backward problem for a nonlinear time fractional wave equation in a bounded domain. By applying the properties of Mittag-Leffler functions and the method of eigenvalue expansion, we establish some results about the existence and uniqueness of the mild solutions of the proposed problem based on the compact technique. Due to the ill-posedness of backward problem in the sense of Hadamard, a general filter regularization method is utilized to approximate the solution and further we prove the convergence rate for the regularized solutions.
Cross-cultural research is burgeoning. Behavioral and social sciences such as psychology, sociology, management, marketing, and political science witness a steady increase in cross-cultural studies. For example, during the last decades, there has been a consistently increasing number of psychological studies on cross-cultural similarities and differences (Boer, Hanke, & He, 2018; Smith, Harb, Lonner, & Van de Vijver, 2001; Van de Vijver & Lonner, 1995). The increased interest is undoubtedly inspired by various factors, such as the opening of previously sealed international borders, large migration streams, globalization of the economic market, international tourism, increased cross-cultural communications, and technological innovations such as new means of telecommunication.
In the previous chapters, typical problems and pitfalls of cross-cultural research were discussed and solutions proposed. The current chapter briefly integrates the major methodological issues into eight statements. Each statement is followed by an explanation. The last section is devoted to our view on the future of cross-cultural research.
This chapter contains a description of the sampling of cultures, design, data analysis, and major strengths and weaknesses of the eight types of cross-cultural studies described in Chapter 2: structure- and level-oriented psychological differences studies; structure- and level-oriented generalizability studies; structure- and level-oriented contextual linkage exploration studies; and structure- and level-oriented contextual linkage validation studies. The structure- and level-oriented studies differ primarily in the analyses employed, so their presentation is integrated. A schematic overview is given in Table 5.1.
This book addresses the methodological features of cross-cultural research. The common characteristic of such studies is their comparative nature, which involves the comparison of at least two cultural populations. Many studies involve different nation states, in sociology (e.g., Inglehart & Welzel, 2010; Van Deth, Montero, & Westholm, 2007), education (e.g., Arnove, Torres, & Franz, 2012; Van de Werfhorst & Mijs, 2010), political sciences (e.g., Coffé & Bolzendahl, 2010; Poguntke & Webb, 2007), management (e.g., House et al., 2004), and psychology (e.g., Schmitt, Allik, McCrae, & Benet-Martínez, 2007). However, comparative studies can also involve different ethnic groups from a single country such as the comparison of ethnic groups in the United States (e.g., Trinidad, Pérez-Stable, White, Emery, & Messer, 2011) and in Europe (Phalet & Kosic, 2006).
Two closely related concepts play an essential role in cross-cultural comparisons, namely equivalence and bias (Poortinga, 1989; Van de Vijver, 2015). There is no consensual definition of either concept in the cross-cultural literature. Johnson (1998) identified more than fifty types of definitions of equivalence, addressing dissimilar features, such as constructs, methodology, language, and context. All definitions refer to some aspect that is shared across cultures or to a qualitative or quantitative procedure to establish the shared features. A review of bias approaches would probably show a comparable variety.
Four procedures for sampling cultures can be discerned (cf. Boehnke, Lietz, Schreier, & Wilhelm, 2011). In convenience sampling, researchers select a culture simply because of considerations of convenience. These considerations can derive from various sources; researchers may be from that culture, are acquainted with collaborators from that culture, or happen to stay there for a period of time. The choice of culture is not related to the theoretical questions raised and is often haphazard. Studies adopting this sampling scheme often fall into the category of psychological differences studies.
Data analysis in cross-cultural research involves more than the preparation of the correct instructions to run a computer program of a statistical package. It is a link in the long chain of empirical research that starts with the specification of a theoretical framework and ends with drawing conclusions. Strategic decisions in the data analysis such as the choice of statistical techniques can only be made on the basis of a combination of substantive considerations such as the research questions or hypotheses involved and statistical considerations such as measurement level and sample size.