This study investigated the etiology of preschoolers’ somatic symptoms and internalizing problems, using a twin sample. A specific focus was placed on the genetic (i.e., DRD4 and 5-HTTLPR) and environmental (i.e., SES, household chaos, family conflict, and maternal emotional stability) factors that were hypothesized to be associated with these problems. This project also explored the possible gene-environmental interactions (GxE) that may exist among these contributors. It was hypothesized that children who are at greatest risk due to their genotype, environment, or a combination of the two would display elevated somatic symptoms and internalizing problems, compared to children who were less at-risk due to these factors. Data from 252 families included in the Southern Illinois Twins/Triplets and Siblings Study (SITSS) at age 5 were examined. Results indicated a significant DRD4 x household chaos interaction predicting preschoolers’ somatic symptoms, demonstrating that children with the DRD4-7r genotype exhibited less somaticizing in highly chaotic homes. Additionally, 5-year-old internalizing problems were significantly predicted by the cumulative environmental risk factor created (i.e., top 15% of scores for each environmental variable in the current sample) and marginally by the additive genotypic risk factor (i.e., a summation of the DRD4 and 5-HTTLPR “risk” scores). These results provide additional insight into the factors that may place children at greater risk for somatic symptoms and internalizing problems.

Introdução: Embora o nascimento de gêmeos tenha sempre chamado atenção, não há fatores genéticos ou ambientais conhecidos que podem determinar o nascimento de monozigóticos gêmeos (MZ). E mesmo para gêmeos dizigóticos (DZ), influências genéticas não são completamente compreendidas. Objetivos: Um estudo prévio do nosso grupo demonstrou que o alelo C do polimorfismo rs1042522 no gene TP53 foi mais frequente nas mães de gêmeos do que nas mães de gestação única em uma pequena cidade no sul do Brasil. A fim de esclarecer se este foi um fator isolado, foi realizado um estudo observacional de caso-controle de base populacional. Métodos: As amostras foram selecionadas a partir de um programa de investigação de paternidade financiado pelo estado do Rio grande do Sul. As amostras foram consideradas casos em que duas das crianças tinham a mesma data de nascimento e os controles eram de amostras em que pelo menos dois filhos nasceram em datas diferentes. O método de escolha dos controles foi sequencial, sendo utilizados os primeiros que preenchessem esta condição a cada ano. Resultados: De 2007 a 2013, foram 32.661 registros pesquisados e 283 (0,9%) gêmeos foram encontrados (119 MZ e 164 DZ). Frequências alélicas e genotípicas não foram diferentes entre as mães de gêmeos ou mães de não gêmeos. No entanto, as mães de gêmeos MZ apresentaram uma maior frequência do genótipo GG e menor frequência do alelo C quando comparado com as mães de gêmeos DZ. Além disso, a proporção de gêmeos monozigóticos (42%) é maior do que normalmente relatado (30%). Finalmente, a proporção de gêmeos encontrados neste estudo parece ser mais realista, já que esta amostra não é supostamente de usuárias de técnicas de reprodução assistida. / Introduction: Although the birth of twins has always attracted attention, there are no known genetic or environmental factors that can determine the birth of monozygotic (MZ) twins. And even for dizygotic (DZ) twins, genetic influences are not completely understood. Objective: A previous study from our group has shown that the C allele of polymorphism rs1042522 in TP53 gene was more frequent in the mothers of twins than in the mothers of singletons in a small village in South Brazil. In order to clarify if this was an isolated factor, we performed a population-based observational case-control study. Methods: Samples were selected from a state-funded program of paternity investigation. Samples were considered cases when two of the children had the same date of birth whereas controls were those samples in which at least two children were born in different dates. The first subsequent sample fulfilling control criteria was included after each case. Results: From 2007 to 2013, 32,661 records were searched and 283 (0.9%) twins were found (119 MZ and 164 DZ). Genotypic and allele frequencies were not different between mothers of twins or mothers of singletons. However, mothers of MZ twins showed a higher frequency of GG genotype and lower frequency of the C allele when compared to mothers of DZ twins. Also, the proportion of MZ twins (42%) is higher than usually reported (30%). Finally, the proportion of twins found in this study seems to be more realistic, as this sample is allegedly not user of assisted reproduction techniques.

abstract: The purpose of the current study was to use structural equation modeling-based quantitative genetic models to characterize latent genetic and environmental influences on proneness to three discrete negative emotions in middle childhood, according to mother-report, father-report and in-home observation. One primary aim was to test the extent to which covariance among the three emotions could be accounted for by a single, common genetically- and environmentally-influenced negative emotionality factor. A second aim was to examine the extent to which different reporters appeared to be tapping into the same genetically- and environmentally-influenced aspects of each emotion. According to mother- and father-report, moderate to high genetic influences were evident for all emotions, with mother- and father-report of fear and father-report of anger showing the highest heritability. Significant common environmental influences were also found for mother-report of anger and sadness in both univariate and multivariate models. For observed emotion, anger was moderately heritable with no evidence for common environmental variance, but sadness, object fear and social fear all showed modest to moderate common environmental influences and no significant genetic variance. In addition, cholesky decompositions examining genetic and environmental influences across reporter suggested that despite considerable overlap between mother-report and father-report, there was also reporter-specific variance on anger, sadness, and fear. Specifically, there were significant common environmental influences on mother-report of anger- and sadness that were not shared with father-report, and genetic influences on father-report of sadness and fear that were not shared with mother-report. In-home observations were not highly correlated enough with parent-report to support multivariate analysis for any emotion. Finally, according to both mother- and father-report, a single set of genetic and environmental influences was sufficient to account for covariance among all three negative emotions. However, fear was primarily explained by genetic influences not shared with other emotions, and anger also showed considerable emotion-specific genetic variance. In both cases, findings support the value of a more emotion-specific approach to temperament, and highlight the need to consider distinctions as well as commonalities across emotions, reporters and situations. / Dissertation/Thesis / M.A. Psychology 2013

Na literatura psicológica, encontramos pesquisas realizadas com gêmeos visando estudar a influência de fatores genéticos versus ambientais na estruturação da personalidade e também no campo da psicopatologia. Entretanto, existem poucos relatos de pesquisas voltados para a interação intra-par de gêmeos e entre os gêmeos e seus cuidadores, especialmente em relação às questões edípicas. O fenômeno, tão estudado pela psicanálise, tem sido pouco investigado na vivência de situações triangulares entre os co-gêmeos e seus pais. O método de Observação Psicanalítica modelo Esther Bick inspirou o planejamento desta tese, que tem como objetivos: observar e descrever as relações objetais triangulares entre os gêmeos e seus pais durante o primeiro ano de vida; analisar a possibilidade de a triangulação edípica ocorrer prioritariamente entre o par de gêmeos; verificar se a \"presença real\" do co-gêmeo poderia exacerbar a vivência como \"terceiro excluído\" entre os gêmeos. Participaram cinco pares de gêmeos recém-nascidos e suas respectivas famílias, sendo dois pares masculinos(monozigoto e dizigoto), dois pares femininos (monozigoto e dizigoto) e um par de sexos diferentes. Foram realizadas visitas semanais com duração de uma hora cada, às residências dos gêmeos, durante o primeiro ano de vida, a fim de observar os gêmeos e seus cuidadores. A observadora pode presenciar o que se passava na relação intra-par de gêmeos, bem como entre os gêmeos e demais pessoas presentes. Após cada sessão de observação foi elaborado um relatório constando os comportamentos observados e as percepções da observadora em relação aos fatos. Foram estudados especialmente os seguintes fenômenos observados nas famílias de gêmeos: atendimento individual mãe-gêmeos; atendimento conjunto mãe-gêmeos; disputa de colo/atenção materna; atendimento pai-gêmeos; relacionamento intra-par de gêmeos. As relações triangulares envolvendo os co-gêmeos e seus pais foram analisadas, tendo como subsídio as teorias de Freud e Klein a respeito das questões edípicas. Foram percebidas quatro formas de relação triangular além do triângulo edípico filho-mãe-pai nas famílias estudadas. / In the psychological literature, we have found researches performed with twins where the aim was to study the influence of genetic factors versus environmental ones in the structuring of the personality and also in the field of the psychology. However, there are few reports of researches related to the twins\' intra-pair interaction and between the twins and their caretakers, especially in relation to the oedipal issues. The phenomenon, so studied by the psychoanalysis, has been little investigated in the experience of triangular situations between the co-twins and their parents. Esther Bick method of Psychoanalytic Observation model inspired the planning of this thesis, which has as its objectives: to observe and to describe the oppose triangular relationships between the twins and their parents during the first year of life; to analyze the possibility that the oedipal triangulation may happen essentially between the pair of twins; to verify if the \"real presence\" of the co-twin could exacerbate the existence as a \"third excluded\" between the twins. Five pairs of just born twins and their respective families participated in the study; among them we have two male pairs (monozygotic and dizygotic twins), two female pairs (monozygotic and dizygotic twins) and a pair of different sexes. Weekly visits were carried out with an hour duration each, to the twins\' residences, during the first year of life, in order to observe the twins and their caretakers. The observer could witness what happened in the twins\' intra-pair relationship, as well as between the twins and among the other people present. After each observation session a report was elaborated including the observed behaviors and the observer\'s perceptions related to the facts. The following observed phenomena were specially studied in the twins\' families: individual attendance mother-twin; pair attendance mother-twins; dispute of mother\'s holding/attention; father-twins attendance; twins\' intra-pair relationship. The triangular relationships involving the co-twins and their parents were analyzed, having as its subsidy Freud\'s and Klein\'s theories regarding to oedipal relations. It has been noticed four triangular relationship forms besides the triangle son-mother-father oedipal one in the studied families.

Abstract Respiratory distress syndrome (RDS) is a disease characterized by neonatal respiratory failure. It is principally caused by a deficiency of pulmonary surfactant, which is a lipoprotein mixture essential for reducing surface tension at the air-liquid interface of the alveolus. Prematurity is the major risk factor predisposing to RDS. Several pieces of evidence suggest the role of genetic factors in the susceptibility to this multifactorial disease. The present study was performed to determine whether polymorphisms of the surfactant protein SP-A1, SP-A2 and SP-B genes associate with RDS and to evaluate the relative contributions of genetic and environmental factors to the disease etiology. Allelic associations between the candidate genes and RDS were investigated using a matched and unmatched case-control and family-based study design. Disease concordance in monozygotic vs. dizygotic twin pairs was determined to measure the impact of heredity in RDS. SP-A and SP-B genes were shown to play a significant role in susceptibility to RDS. In very premature singleton infants born before 32 weeks of gestation, SP-A1 and SP-A2 allelic variations were associated with RDS, whereas the SP-B gene showed no direct association. Instead, the association between the high-risk (6A2, 1A0) or low-risk (6A3, 1A1/1A2) SP-A alleles and RDS was dependent on SP-B Ile131Thr variation, being restricted to a subset of infants carrying the homozygous genotype Thr/Thr. No allelic associations were evident in premature infants born after 32 weeks of gestation. RDS concordance was not significantly higher in monozygotic than in dizygotic twin pairs, implying a non-genetic disease etiology. However, the present study suggests that the concordance difference underestimates the extent of heredity. Twin pregnancies include intrauterine environmental factors that complicate the interpretation of the hereditary impact. SP-B Ile131Thr variation was associated with RDS in the first-born, but not in the second-born twins. The present results indicate that susceptibility to RDS is highly heterogeneous, involving complex environmental and genetic interactions. The degree of prematurity, singleton vs. multiple pregnancy, and birth order in a multiple birth are environmental confounders that determine disease subgroups. Genetic variations in the SP-A and SP-B genes account for part of the genetic component of RDS.

Background: Breastfeeding twins implies that the mother breastfeeds children of the same age and the children can be breastfed either together or separately. There are many benefits with breastfeeding twins, including the fostering of attachment. Breastfeeding is often represented as a natural and easy process, however, many mothers find the experience to be challenging. Aim: This study aimed to describe how mothers experience breastfeeding twins. Method: The study was conducted through a meta synthesis where qualitative research was included. Searches for articles were made through the electronic databases PubMed and CINAHL. A total of ten scientific studies with qualitative design were included. Results: The results are based on four main themes; 1) Experiences of physically influential factors. The mothers experienced difficulties breastfeeding twins simultaneously and found it time-consuming. 2) Experiences of psychologically influential factors. The mothers felt insecure and were afraid that there wouldn’t be enough breastmilk for both twins. 3) Experiences of support from the surroundings. The support from the mothers’ partner and her surroundings was shown to be important and improved the conditions for breastfeeding the twins. Finally, 4) Experiences of the community's influence. The mothers experienced some benefits during hospitalisation with the twins but mostly disadvantages, which complicated the breastfeeding. Conclusion: Mothers’ experiences of breastfeeding twins were found to be both negative and positive as seen from a physical and psychological perspective. The results indicate the importance of support from the healthcare staff when breastfeeding, which further promotes the attachment between the mother and her children. The nurse has a significant role in encouraging the mother's self-efficacy, independence and motivation to breastfeed her twins for as long as the mother and the children wishes. / Bakgrund: Tvillingamning innebär att mamman ammar syskon i samma ålder och barnen kan ammas var för sig eller samtidigt. Det finns många fördelar med att amma tvillingar, bland annat främjar det anknytningen. Amning framställs ofta som en naturlig och enkel process, men för många mammor upplevs tvillingamningen som svår och mer utmanande än de kunnat föreställa sig. Syfte: Syftet med arbetet var att beskriva hur mammor upplever det att tvillingamma. Metod: Syftet besvarades genom en metasyntes där forskning med kvalitativ ansats inkluderades. Artikelsökningarna genomfördes i databaserna PubMed och CINAHL och resulterade i tio vetenskapliga kvalitativa studier. Resultat: Resultatet sammanfattades genom fyra huvudsakliga teman; 1) Upplevelser av fysiskt påverkande faktorer. Mammorna upplevde att det var svårt att amma två barn samtidigt och att amningen var tidskrävande. 2) Upplevelser av psykiskt påverkande faktorer. Mammorna kände osäkerhet och rädsla över att bröstmjölken inte skulle räcka till båda tvillingarna. 3) Upplevelser av stöd från omgivningen. Stöd från partner och andra personer i omgivningen var viktigt och ökade förutsättningarna för att amma tvillingarna. Slutligen 4) Upplevelser av samhällets påverkan. Mammorna upplevde vissa fördelar men mestadels nackdelar med att vistas på sjukhus med sina tvillingar, vilket försvårade amningen. Slutsats: Mammor upplevde amningen både som något positivt och negativt sett från ett fysisk samt psykiskt perspektiv. Resultatet visade även på betydelsen av stödet mammor erhöll från sjukvårdspersonal kring sin amning, vilket kan gynna anknytningen/bindningen mellan tvillingarna och mamman. Sjuksköterskan har en viktig roll i att främja mammornas självkänsla, självständighet och motivation till att amma sina tvillingar så länge som mamman och barnet önskar.

Childhood callous-unemotional traits (CU), defined as a lack of guilt, empathy, and affect, are important in understanding conduct problems and other maladaptive behaviors. Early CU, in particular, has received recent attention, though current conceptualizations often extrapolate from the adult literature and lack a more nuanced developmental perspective. CU, however, may manifest differently earlier in development. The aims of this project were to further our current understanding of the early CU construct by investigating; 1) long-term stability and its underlying genetic and environmental etiology from early childhood to adolescence; 2) structural, developmental, and etiological similarities and distinctions between CU and prosociality; and 3) the extent to which early CU and prosociality differentially predict adolescent outcomes. I hypothesized modest stability and predictive validity of early CU into adolescence, and expected early CU and prosociality to be separate but related constructs. Two longitudinal twin samples were used to address these aims (Sample 1: Ages 2 and 3 years [N=314 twin pairs], followed-up in adolescence M=14.5 years [N=128 twin pairs]; Sample 2: Ages 3, 4, and 5 years [N=310 twin pairs]). Study hypotheses were largely supported. In Study 1 (Sample 1), parent-reported CU was modestly stable, and common genetic factors contributed to this stability. However, most of the genetic and environmental variance was unique to adolescent CU. In Study 2 (Sample 2), confirmatory factor analysis, longitudinal growth modeling, and twin analyses supported early CU and prosociality as distinct but related constructs at the structural, developmental, and etiological level, respectively. Study 3 (Sample 1) further supported distinctions between early CU and low prosociality by demonstrating that both independently predicted adolescent externalizing behavioral outcomes. These studies highlight the long-term developmental significance of early CU, in both its stability and predictive validity into adolescence. Furthermore, this work demonstrates the relevance of prosociality to our understanding of early CU, highlighting the utility of integrating childhood CU research with work on normative prosocial development. That being said, CU and prosociality are not simply flip sides of the same coin in early childhood, and should be viewed as distinct constructs that independently explain maladaptive behavior.

Introduction: The gut microbiome is believed to have a significant impact on health throughout the lifespan, and the influence of infant nutrition and other environmental factors are of particular interest in its development. The aim of this research project was to learn more about the microbiome and short chain fatty acid (SCFA) composition of toddlers of differing weights, considering birth history, environment, and diet. In East Tennessee, opioid misuse is a growing issue, and a number of participants in this study were exposed in utero. We also hoped to identify related effects on infant’s SCFA composition. Finally, it is known that twins share a variety of traits, but much about their microbiome is unknown. With several pairs of twins in the sample, we aimed to identify any associations with SCFAs in this group. Methods: With informed consent, the child’s history was obtained, including age, birth length and weight, delivery type (C-section or vaginal), and feeding method (breast, bottle fed, or both). The child’s current weight, height, and BMI percentile were determined. Caregivers completed a 90-question Block Questionnaire for Ages 2-7 Kids food frequency questionnaire, and results were analyzed by Berkeley Analytics Inc (dba NutritionQuest). Participant-provided stool samples were freeze-dried and ground, and SCFAs were extracted and analyzed by content area % and concentration ppm. Data analysis was generated using SAS software, Version 9.4 of the SAS System, Copyright © 2013 SAS Institute Inc. Results: Nine SCFAs were measured in duplicate, and the concentrations averaged. Statistical analysis included comparisons of SCFAs related to factors including weight status, infant feeding modality, twin status, and intrauterine drug exposure, and significance determined with a p value < 0.05. Results did not identify significant differences in individual SCFA concentrations between obese and non-obese toddlers, however concentrations of isobutyrate, isovaleric acid, and octanoic acid were greater in toddlers who were formula fed as infants versus toddlers who were breastfed, and those fed a combination of breastmilk, and formula. Analysis further revealed a higher mean concentration of caproic and propionic acid in twin subjects. Of particular interest, toddlers with a history of opioid exposure had higher mean concentrations of isovaleric and octanoic acids, but less isocaproic acid when compared to those who were not drug exposed. Further analysis will help determine if these findings may be related to nutrient intake, in particular dietary fiber intake.

Children's relationships with their parents are considered to be a major influence in their development. Parents' use of discipline with their children, in particular, constitutes a major component of the parent-child relationship and is linked to children's later social skills and behavioral and emotional functioning. Prior studies have shown that parents treat their children differently. The purpose of this dissertation was to examine whether parents use differing levels of discipline with their children and to delineate parent, child, and contextual factors associated with differential parental discipline. This study utilized a behavior genetics twin study design to control for extraneous influences, such age and life changes, which may significantly impact a parents' use of discipline. Participants in this study consisted of 38 families (36 twin pairs, 2 sets of triplets) who had previously participated in the Southern Illinois Twins and Siblings Study (SITSS; DiLalla, 2002) and were now between the ages of 5 ½ to 10 ½. Children and their parents were each asked to report on various parenting practices and discipline techniques used within their home. Parents completed a variety of questionnaires assessing socioeconomic status, interparental conflict, parent personality, child temperament, and child emotional and behavioral functioning and mothers tracked their discipline for one week through a diary. Results from this study showed that children living in the same family experience different levels and types of discipline. Child temperament and emotional/behavioral functioning were related to differential discipline practices. The twin in the family rated as exhibiting greater levels of extraversion, effortful control, and prosocial skills received more sensitive parental discipline. In contrast, the twin showing more conduct problems, peer problems, emotional symptoms, and inattention/ hyperactivity experienced harsher parental discipline. Importantly, parents and their children did not agree on the amount of differential discipline used in their homes. Parents reported using similar levels of discipline with both of their children and children reported large differences in the type and amount of discipline shown to them and their co-twins. Findings from this study could add to the effectiveness of many parent training programs by helping parents to understand the interactions between various parent, child, and contextual characteristics in the initiation of parental disciplinary strategies. Through this understanding, parents may begin to match their disciplinary styles to best meet their children's phenotypic characteristics and needs and environmental demands. Lastly, the search for various genetic and environmental factors associated with harsh discipline practices will greatly enhance the success of prevention programs. By being able to determine familial and contextual characteristics associated with harsh or aversive punishment practices, we may be able to predict those parents most at risk for harsh discipline and to intervene before abusive discipline practices are used.

Mobile computation offloading (MCO) is a way of improving mobile device (MD) performance by offloading certain task executions to a more resourceful edge server (ES), rather than running them locally on the MD. This thesis first considers the problem of assigning the wireless communication bandwidth and the ES capacity needed for this remote task execution, so that task completion time constraints are satisfied. The objective is to minimize the average power consumption of the MDs, subject to a cost budget constraint on communication and computation resources. The thesis includes contributions for both soft and hard task completion deadline constraints. The soft deadline case aims to create assignments so that the probability of task completion time deadline violation does not exceed a given violation threshold. In the hard deadline case, it creates resource assignments where task completion time deadlines are always satisfied. The problems are first formulated as mixed integer nonlinear programs. Approximate solutions are then obtained by decomposing the problems into a collection of convex subproblems that can be efficiently solved. Results are presented that demonstrate the quality of the proposed solutions, which can achieve near optimum performance over a wide range of system parameters. The thesis then introduces algorithms for static task class partitioning in MCO. The objective is to partition a given set of task classes into two sets that are either executed locally or those classes that are permitted to contend for remote ES execution. The goal is to find the task class partition that gives the minimum mean MD power consumption subject to task completion deadlines. The thesis generates these partitions for both soft and hard task completion deadlines. Two variations of the problem are considered. The first assumes that the wireless and computational capacities are given and the second generates both capacity assignments subject to an additional resource cost budget constraint. Two class ordering methods are introduced, one based on a task latency criterion, and another that first sorts and groups classes based on a mean power consumption criterion and then orders the task classes within each group based on a task completion time criterion. A variety of simulation results are presented that demonstrate the excellent performance of the proposed solutions. The thesis then considers the use of digital twins (DTs) to offload physical system (PS) activity. Each DT periodically communicates with its PS, and uses these updates to implement features that reflect the real behaviour of the device. A given feature can be implemented using different models that create the feature with differing levels of system accuracy. The objective is to maximize the minimum feature accuracy for the requested features by making appropriate model selections subject to wireless channel and ES resource availability. The model selection problem is first formulated as an NP-complete integer program. It is then decomposed into multiple subproblems, each consisting of a modified Knapsack problem. A polynomial-time approximation algorithm is proposed using dynamic programming to solve it efficiently, by violating its constraints by at most a given factor. A generalization of the model selection problem is then given and the thesis proposes an approximation algorithm using dependent rounding to solve it efficiently with guaranteed constraint violations. A variety of simulation results are presented that demonstrate the excellent performance of the proposed solutions. / Thesis / Doctor of Philosophy (PhD) / Mobile devices (MDs) such as smartphones are currently used to run a wide variety of application tasks. An alternative to local task execution is to arrange for some MD tasks to be run on a remote non-mobile edge server (ES). This is referred to as mobile computation offloading (MCO). The work in this thesis studies two important facets of the MCO problem. 1. The first considers the joint effects of communication and computational resource assignment on task completion times. This work optimizes task offloading decisions, subject to task completion time requirements and the cost that one is willing to incur when designing the network. Procedures are proposed whose objective is to minimize average mobile device power consumption, subject to these cost constraints. 2. The second considers the use of digital twins (DTs) as a way of implementing mobile computation offloading. A DT implements features that describe its physical system (PS) using models that are hosted at the ES. A model selection problem is studied, where multiple DTs share the execution services at a common ES. The objective is to optimize the feature accuracy obtained by DTs subject to the communication and computation resource availability. The thesis proposes different approximation and decomposition methods that solve these problems efficiently.