bluuebunny/crossref_metadata_2025_split huggingface dataset:
Variations in the Maternal Age Effect on Twinning Rates: The Nordic Experience
Authors: Fellman Johan , Eriksson Aldur W. 
Published: May 2007

AbstractMaternal age is the most important nongenetic factor influencing the twinning rate. Every study of the effect of other factors should consider the age distribution of the mothers. Besides standardizing techniques, the age-specific twinning rates are analyzed. Especially, the slope of the regression line is considered when the age-specific twinning rates are regressed against maternal age. How well the maximum age-specific twinning rate measures the variation in the maternal age effect is also studied. The two measures, which are strongly correlated, give consistent results. The proposed methods are applied to data from Finland (1866 to 2003) and Denmark (1855 to 2000). Comparisons with Sweden (1861 to 2000) and Norway (1855 to 2003) are also made. In general, marked decreasing trends in the twinning rates are discernible up to the middle of the 20th century. In Sweden the decline starts around the beginning of the 20th century and is stronger than in Denmark and Norway. The decrease in the twinning rate for Finland, which up to World War II was rather isolated, sets in around the middle of the 20th century and is not as strong as in other Nordic countries. After the minima around 1980, strong increasing trends are noted. This is mainly caused by the influence of the artificial reproduction technologies and particularly the use of fertility-enhancing drugs on the commonly noted dependence between maternal age and the twinning rate. Similar temporal trends can be observed in the slopes of the regression line and in the maximum age-specific twinning rates.
The Hispanic Paradox in Twin Pregnancies
Authors: Luke Barbara , Brown Morton B. , Misiunas Ruta B. , Gonzalez-Quintero Victor H. , Nugent Clark , van de Ven Cosmas , Witter Frank R. , Newman Roger B. , D'Alton Mary , Hankins Gary D. V. , Grainger David A. , Macones George A. 
Published: May 2007

AbstractThe objective of this study was to compare length of gestation, fetal growth, and birthweight by race/ethnicity and pregravid weight groups in twin pregnancies. Three thousand and thirty-six twin pregnancies of 28 weeks or more gestation were divided by race/ethnicity (White, Black and Hispanic), and pregravid body mass index (BMI) groups (less than 25.0 vs. 25.0 or more). Outcomes were modeled using multiple regression, controlling for confounders, with White non-Hispanic women as the reference group. Hispanic women had the highest average birthweight and the longest gestation, as well as the lowest proportions of low birthweight, very low birthweight, preterm and early preterm births of the 3 race/ethnicity groups. In the multivariate analyses, Hispanic women had significantly longer gestations (by 7.8 days) and faster rates of fetal growth midgestation (20 to 28 weeks, by 17.4 g/week) and late gestation (after 28 weeks, by 5.3 g/week), whereas Black women had significantly slower rates of fetal growth (by 5.7 g/week and by 4.5 g/week, respectively). These findings in twins reflect the racial and ethnic disparities previously shown in singletons, including the Hispanic paradox of longer gestations and higher rates of fetal growth.
Twin Transplants; Twin Study Summary; Human Interest Topics
Authors: Segal Nancy L. 
Published: May 2007

AbstractAn overview of the nature and success of organ transplantation in monozygotic (MZ) twins is presented. Recent timely examples demonstrate the unique donor–recipient relationship shared by MZ co-twins. Next, a recent analysis of MZ co-twin differences in the epigenetic profile and associations with differences in life history factors is presented. This work has been the focus of considerable attention by scientists and the media. The final section of this column summarizes information and events concerning twins' longevity, screen careers, older parenting of twins and the origin of the word ‘twin’.
Genetic Influence on Reproductive Behavior in Female Rhesus Macaques
Authors: Trefilov Andrea , Croucher Peter J. P. , Krawczak Michael , Schmidtke Jörg 
Published: May 2007

AbstractCommentary on Cherkas et al. (2004). Genetic Influences on Female Infidelity and Number of Sexual Partners in Humans: A Linkage and Association Study on the Role of the Vasopressin Receptor Gene (AVPR1A). Twin Research, 7, 649–658.
Genetic Etiology of Reading Difficulties in Boys and Girls
Authors: Wadsworth Sally J. , DeFries John C. 
Published: May 2007

AbstractAlthough it has been suggested that genetic influences on reading difficulties may differ in boys and girls, results obtained from previous analyses of data from same-sex twin pairs have failed to provide evidence for a differential genetic etiology of reading disability (RD) as a function of gender. However, results of a recent study in which data from both same-sex and opposite-sex twin pairs were analyzed indicated a higher heritability for reading difficulties in boys (Harlaar et al., 2005). Because the current sample of twin pairs tested in the Colorado Learning Disabilities Research Center is substantially larger than that analyzed for our previous report (Wadsworth et al., 2000), this hypothesis was tested more rigorously using data from both same-sex and opposite-sex twin pairs in our current augmented sample. Composite reading scores from 634 twin pairs were subjected to DeFries–Fulker sex-limitation analysis using the model-fitting approach of Purcell and Sham (2003). Analysis of data from the combined sample of male and female twins indicated that genetic influences account for more than half the proband reading deficit (h2g = .58). When this model was extended to test for gender differences in the magnitude of genetic influences on RD, h2g estimates were somewhat higher for females than for males (.63 and .53, respectively), but the difference was nonsignificant (p > .3). A test for qualitative gender differences was also nonsignificant. Thus, these results provide little evidence for a differential genetic etiology of RD in boys and girls.
Familial Clustering of Major Depression and Anxiety Disorders in Australian and Dutch Twins and Siblings
Authors: Middeldorp Christel M. , Birley Andrew J. , Cath Danielle C. , Gillespie Nathan A. , Willemsen Gonneke , Statham Dixie J. , de Geus Eco J. C. , Andrews J. Gavin , van Dyck Richard , Beem A. Leo , Sullivan Patrick F. , Martin Nicholas G. , Boomsma Dorret I. 
Published: May 2007

AbstractThe aim of this study was to investigate familial influences and their dependence on sex for panic disorder and/or agoraphobia, social phobia, generalized anxiety disorder and major depression. Data from Australian (N= 2287) and Dutch (N= 1185) twins and siblings who were selected for a linkage study and participated in clinical interviews to obtain lifetimeDiagnostic and Statistical Manual of Mental Disorders(4th ed.; DSM-IV) diagnoses were used. In a liability model, tetrachoric correlations were estimated in sibling pairs and sex differences between sibling correlations were tested. For each diagnosis, the sibling correlations could be constrained to be equal across the Australian and Dutch samples. With the exception of panic disorder and/or agoraphobia, all sibling correlations were the same for brother, sister and opposite-sex sibling pairs and were around .20. For panic disorder and/or agoraphobia, the correlation was .23 in brother and sister pairs, but absent in opposite-sex sibling pairs. From these results it can be concluded that upper heritability estimates, based on twice the correlations in the sibling pairs, vary between 36% (major depression) and 50% (social phobia). Furthermore, different genetic risk factors appear to contribute to the vulnerability for panic disorder and/or agoraphobia in men and women. No other sex differences were found.
A Comparison of Twin Birthweight Data From Australia, the Netherlands, the United States, Japan, and South Korea: Are Genetic and Environmental Variations in Birthweight Similar in Caucasians and East Asians?
Authors: Hur Yoon-Mi , Luciano Michelle , Martin Nicholas G. , Boomsma Dorret I. , Iacono William G. , McGue Matt , Shin Joong Sik , Jun Jong Kwan , Ooki Syuichi , van Beijsterveldt C. E. M. , Han Jung Yeol 
Published: May 2007

AbstractBirthweight has implications for physical and mental health in later life. Using data from Caucasian twins collected in Australia, the Netherlands and the United States, and from East Asian twins collected in Japan and South Korea, we compared the total phenotypic, genetic and environmental variances of birthweight between Caucasians and East Asians. Model-fitting analyses yielded four major findings. First, for both males and females, the total phenotypic variances of birthweight were about 45% larger in Caucasians than in East Asians. The larger phenotypic variances were mainly attributable to a greater shared environmental variance of birth- weight in Caucasians (ranging from 62% to 67% of variance) than Asians (48% to 53%). Second, the genetic variance of birthweight was equal in Caucasians and East Asians for both males and females, explaining a maximum of 17% of variance. Third, small variations in total phenotypic variances of birthweight within Caucasians and within East Asians were mainly due to differences in nonshared environmental variances. We speculate that maternal effects (both genetic and environmental) explain the large shared environmental variance in birthweight and may account for the differences in phenotypic variance in birthweight between Caucasians and East Asians. Recent molecular findings and specific environmental factors that are subsumed by maternal effects are discussed.
Analysis of Factors Affecting Birthweight, Birth Length and Head Circumference: Study of Japanese Triplets
Authors: Yokoyama Yoshie , Sugimoto Masako , Ooki Syuichi 
Published: May 2007

AbstractThe aims of this study were to identify factors associated with birthweight, birth length and head circumference for triplets, and analyze these body size parameters at birth, especially head circumference, according to gestational age. The subjects of this study were 370 mothers and their 1109 triplet children (excluding one stillborn infant) who were born between 1978 and 2002. The gestational age proved to be the strongest contributing factor to birthweight, birth length and head circumference of the triplets. Moreover, sex was a significant factor affecting birthweight, birth length and head circumference. Male neonates had a higher birthweight, longer birth length and greater head circumference than female neonates. Birth order in triplets also had a significant effect on birthweight and head circumference. Lower birth- order neonates had a higher birthweight and greater head circumference. An effect of maternal pregravid body mass index (BMI) on both birth- weight and birth length was observed. The birthweights of triplets born to women whose pregravid BMIs were more than 26.0 kg/m2 weighed an average of 150 g more than those of triplets born to women whose pregravid BMIs were less than 19.8 kg/m2, and the birth length of triplets born to women whose pregravid BMIs were more than 26.0 kg/m2 averaged 1.5 cm longer than those of triplets born to women whose pregravid BMIs were less than 19.8 kg/m2. Concerning head circumference, the median head circumference of male neonates was approximately 0.5 cm longer than female neonates. Compared to singleton neonates, the median head circumference of triplets was almost the same.
Mesial Migration Effect on Root Morphology of Mandibular Third Molars
Authors: Bıçakçı A. Altuğ , Sökücü Oral , Babacan Hasan , Köşger H. Hüseyin 
Published: May 2007

Abstract
Objective: To test the hypothesis that there is a relationship between forward mandibular third molar migration and root curvature of the mandibular third molars.
Materials and Methods: The study is comprised of 64 patients who had a history of unilateral mandibular first molar extraction before 16 years of age with no other missing teeth or prosthetic restorations in the mandible. The extraction space was fully or partly closed. The mean remaining space was 1.1 ± 0.41 mm. The root angles for the mesial and distal roots of the mandibular third molars were measured on the panoramic radiographs by calculating the differences between the angle formed by the long axis drawn perpendicular to the occlusal plane of the crown of mandibular third molar and the central line of the lower one ninth of the root through the root apex. The differences between the extracted and nonextracted sides for mesial and distal roots were analyzed using a paired sample t-test.
Results: Both mesial and distal roots were approximately 8° more vertical on the extraction sides than on the nonextraction sides. The differences were statistically significant.
Conclusion: Mesial tooth migration of mandibular third molars reduces the amount of root curvature developing on this tooth.
Mandibular Cervical Headgear vs Rapid Maxillary Expander and Facemask for Orthopedic Treatment of Class III Malocclusion
Authors: Baccetti Tiziano , Rey Diego , Angel David , Oberti Giovanni , McNamara James A. 
Published: May 2007

Abstract
Objective: To compare the effectiveness of the rapid maxillary expander and facemask (RME/ FM) and mandibular cervical headgear (MCH) protocols when followed by fixed appliances and evaluated at a postpubertal observation in patients with dentoskeletal Class III malocclusion.
Materials and Methods: The sample treated with the RME/FM followed by fixed appliances included 32 patients (12 boys and 20 girls). The sample treated with the MCH followed by fixed appliances included 26 patients (eight boys and 18 girls). Cephalometric analysis was performed at T1 (before treatment) and T2 (after the first phase of orthopedic therapy and the second phase of fixed appliances). T1-T2 changes were evaluated by means of t-tests.
Results: Midfacial length, mandibular length, and the sagittal position of the chin all showed significantly smaller increases in the MCH group than in the RME/FM group. The amount of increase in the overjet was also significantly smaller in the MCH group, whereas the amount of molar correction was greater. The upper incisors were significantly less proclined and the lower incisors were significantly less retroclined in the MCH group when compared with the RME/FM group.
Conclusions: RME/FM therapy appears to be indicated in Class III patients with a component of maxillary retrusion, whereas MCH therapy is preferable in patients with mandibular prognathism.
Dynamic MRI Evaluation of Tongue Posture and Deglutitive Movements in a Surgically Corrected Open Bite
Authors: Karacay Seniz , Akin Erol , Ortakoglu Kerim , Bengi A. Osman 
Published: May 2007

Abstract
Tongue thrust usually develops in the presence of anterior open bite in order to achieve anterior valve function. In the literature, tongue thrust is described both as the result and the cause of open bite. If it is an adaptation to malocclusion, then tongue posture and deglutitive tongue movements should change after treatment. In this case report, an adult who had skeletal open bite and Class II malocclusion caused by mandibular retrusion was treated surgically. The mandible was advanced in a forward and upward direction with a sagittal split osteotomy. The open bite and Class II malocclusion were corrected and an increase in the posterior airway space (PAS) was observed. Pretreatment and posttreatment dynamic magnetic resonance imaging (MRI) revealed that tongue tip was retruded behind the incisors and contact of the tongue with the palate increased. It was also determined that the anterior and middle portions descended, whereas the posterior portion was elevated at all stages. Advancement of the mandible, correction of open bite, and an increase in PAS affected not only the tongue posture and deglutitive movements, but also the breathing pattern of the patient.
Mandibular First Molar Relation to Variable Lower Face Skeletal Components
Authors: Andria Louis Matthew , Leite Luis Paulo , Dunlap April M. , Cooper Emily C. , King Lydia Buxbaum 
Published: May 2007

Abstract
Objective: To evaluate the position of the mandibular first permanent molar in the mandible relative to several factors.
Materials and Methods: A total of 185 untreated Class I and Class II patients were randomly selected from a sample of 350 patients from a single office. The palatal and mandibular planes were related to Frankfort horizontal to create the interjaw or “B” angle. Age and the mesial contact of the mandibular first molars were used. The landmarks were projected at right angles to the Frankfort horizontal for effective mandibular dimension lengths. Actual-length dimensions were projected at right angles to the mandibular plane. Pearson product moment correlation coefficients were computed to evaluate the effect of age, cranial length, and mandibular contribution to the molar's sagittal position in the mandible. Significance was reported only when P &lt; .05 to determine a 95% confidence level.
Results: Statistically significant positive correlations indicated that the mandibular molar is located more forward with increasing age, longer mandibular body length, and increasing posterior facial height. In contrast, significant negative correlations to the interjaw, mandibular plane, ramal inclination angles, and the linear ramal contribution corresponded to a more posterior position of the molar with increasing angles.
Conclusions: The mandibular first permanent molar is located more anteriorly with an older patient, a longer mandibular body, greater posterior facial height, and an acute interjaw angle. In contrast, an increase in the forward tip of the ramus places the molar in a more posterior location.
Student victimization by school staff in the context of an Israeli national school safety campaign
Authors: Khoury‐Kassabri Mona , Astor Ron Avi , Benbenishty Rami 
Published: May 2007

AbstractIn this study, we examined and compared findings from four nationally representative studies of victimization of students by school staff in Israel. We explored whether levels of student victimization by school staff (teachers, principals, secretaries, janitors, etc.) have changed between 1998, 1999, 2002, and 2005, and whether patterns of group differences (gender, age, and cultural groups) were replicated across those four points in time. We employed representative samples stratified by ethnic affiliation and school levels. In 1998, there were 15,916 4th–11th grade students from 232 schools; in 1999, 16,414 4th–11th grade students from 239 schools; in 2002, 21,577 4th–11th grade students from 410 schools and in 2005, 27,316 4th–11th grade students from 526 schools across Israel. Overall, the results reveal that for the entire student population in Israel reports of victimization are quite similar across the four waves of data collection. Levels of physical victimization were consistently higher among boys and Arab students, but other group differences were less consistent, especially with regard to differences between age groups. Aggr. Behav. 34:1–8, 2008. © 2007 Wiley‐Liss, Inc.
Psychopathy and behavioral correlates of victim injury in serious juvenile offenders
Authors: Vitacco Michael J. , Caldwell Michael F. , Van Rybroek Gregory J. , Gabel Jason 
Published: May 2007

AbstractThe study examines delinquent behavior and psychopathy and assesses their relationship to victim injury in a population of 168 incarcerated juvenile delinquent males with lengthy histories of criminal and violent behavior. A series of multiple regressions found that 17% of the variance associated with level of victim injury was accounted for by a model that included the three‐factor model of the Psychopathy Checklist: Youth Version [Forth, Kosson, and Hare, 2003], criminal versatility, and age of onset of criminal offending. Notably, anger and DSM‐IV symptoms of conduct disorder were not related to level of victim injury. The results of this study support an escalation hypothesis where individuals with earlier onset to criminal behavior and greater criminal versatility escalate to more severe violence. The current results demonstrate the importance of integrating established theories of juvenile delinquency when explaining severe violence in youth. Aggr. Behav. 33:537–544, 2007. © 2007 Wiley‐Liss, Inc.
Actuator fault isolation and reconfiguration in transport‐reaction processes
Authors: El‐Farra Nael H. , Ghantasala Sathyendra 
Published: May 2007

AbstractA methodology is presented for the design of integrated, model‐based fault diagnosis and reconfigurable control systems for transport‐reaction processes modeled by nonlinear parabolic partial differential equations (PDEs) with control constraints and actuator faults. The methodology brings together nonlinear feedback control, fault detection and isolation (FDI), and performance‐based supervisory switching between multiple actuator configurations. Using an approximate, finite‐dimensional model that captures the PDE's dominant dynamic modes, a stabilizing nonlinear feedback controller is initially designed for each actuator configuration, and its stability region is explicitly characterized in terms of the control constraints and actuator locations. To facilitate the fault diagnosis task, the locations of the control actuators are chosen in a way that ensures that the evolution of each dominant mode, in appropriately chosen coordinates, is excited by only one actuator. Then, a set of dedicated FDI filters, each replicating the fault‐free behavior of a given state of the approximate system, are constructed. The choice of actuator locations ensures that the residual of each filter is sensitive to faults in only one actuator and decoupled from the rest, thus, allowing complete fault isolation. Finally, a set of switching rules are derived to orchestrate switching from the faulty actuators to healthy fallbacks in a way that preserves closed‐loop stability and minimizes the closed‐loop performance deterioration resulting from actuator faults. Precise FDI thresholds and control reconfiguration criteria that account for model reduction errors are derived to prevent false alarms when the reduced order model‐based fault‐tolerant control structure is implemented on the process. A singular perturbation formulation is used to link these thresholds with the degree of separation between the slow and fast eigenvalues of the spatial differential operator. The developed methodology is successfully applied to the problem of constrained, actuator fault‐tolerant stabilization of an unstable steady‐state of a representative diffusion‐reaction process. © 2007 American Institute of Chemical Engineers AIChE J, 2007
Extended robust model predictive control of integrating systems
Authors: González Alejandro H. , Marchetti Jacinto L. , Odloak Darci 
Published: May 2007

AbstractThe robust model predictive control (MPC) of systems with stable and integrating modes is addressed. The approach proposed here extends the method presented in Odloak in 2004 that can only be applied to open‐loop stable systems. Here, the robust controller is developed assuming that there is model uncertainty in both stable and integrating parts of the system. The method considers a modified cost function that turns the infinite output horizon MPC globally convergent for any finite input horizon. The controller is based on a modified version of the state‐space model utilized by Carrapiço and Odloak in 2005 to develop a nominally stable MPC for systems with stable and integrating modes. The approach considers the inclusion of feasible cost contracting constraints in the control optimization problem, taking into account the annulment of the integrating modes to assure a bounded infinite horizon cost. A simulation example is included to illustrate the performance and robustness of the proposed approach and to demonstrate that the controller can be implemented in real applications. © 2007 American Institute of Chemical Engineers AIChE J, 2007