bluuebunny/crossref_metadata_2025 huggingface dataset:
Chemosensory reception, behavioral expression, and ecological interactions at multiple trophic levels
Authors: Ferrer Ryan P. , Zimmer Richard K.
Published: May 2007

Chemoreception may function throughout an entire animal lifetime, with independent, stage-specific selection pressures leading to changes in physiological properties, behavioral expression, and hence, trophic interactions. When the California newt (Taricha torosa) metamorphoses from an entirely aquatic larva to a semi-terrestrial juvenile/adult form, its chemosensory organs undergo dramatic reorganization. The relationship between newt life-history stage and chemosensory-mediated behavior was established by comparing responses of adults (as determined here) to those of conspecific larvae (as studied previously). Bioassays were performed in mountain streams,testing responses of free-ranging adults to 13 individual l-amino acids. Relative to stream water (controls), adults turned immediately upcurrent and moved to the source of arginine, glycine or alanine release. These responses were indicative of predatory search. Arginine was the strongest attractant tested, with a response threshold (median effective dose)of 8.3×10–7 mol l–1 (uncorrected for dilution associated with chemical release and delivery). In contrast to adult behavior, arginine suppressed cannibal-avoidance and failed to evoke search reactions in larvae. For a common set of arginine analogs, the magnitudes of adult attraction and larval suppression were not positively correlated. Suppression of cannibal-avoidance behavior in larvae was unaffected by most structural modifications of the arginine molecule. Adult behavior, on the other hand, was strongly influenced by even subtle alterations in the parent compound. Reactions to arginine in both adults and larvae were eliminated by blocking the external openings of the nasal cavity.

Stimulating adult predatory search in one case and inhibiting larval cannibal avoidance in the other, arginine is a chemical signal with opposing behavioral effects and varying ecological consequences. Significant differences between responses of adults and larvae to changes in arginine structure suggest alternative, chemosensory receptor targets. Although arginine reception functions throughout an entire newt lifetime, an ontogenetic shift in larval and adult chemoreceptive ability changes behavioral expression, and thus, reflects the unique selection pressures that act at each life-history stage.
Human locomotion on ice: the evolution of ice-skating energetics through history
Authors: Formenti Federico , Minetti Alberto E.
Published: May 2007

More than 3000 years ago, peoples living in the cold North European regions started developing tools such as ice skates that allowed them to travel on frozen lakes. We show here which technical and technological changes determined the main steps in the evolution of ice-skating performance over its long history. An in-depth historical research helped identify the skates displaying significantly different features from previous models and that could consequently determine a better performance in terms of speed and energy demand. Five pairs of ice skates were tested, from the bone-skates, dated about 1800 BC, to modern ones.

This paper provides evidence for the fact that the metabolic cost of locomotion on ice decreased dramatically through history, the metabolic cost of modern ice-skating being only 25% of that associated with the use of bone-skates. Moreover, for the same metabolic power, nowadays skaters can achieve speeds four times higher than their ancestors could. In the range of speeds considered, the cost of travelling on ice was speed independent for each skate model, as for running. This latter finding, combined with the accepted relationship between time of exhaustion and the sustainable fraction of metabolic power, gives the opportunity to estimate the maximum skating speed according to the distance travelled.

Ice skates were probably the first human powered locomotion tools to take the maximum advantage from the biomechanical properties of the muscular system: even when travelling at relatively high speeds, the skating movement pattern required muscles to shorten slowly so that they could also develop a considerable amount of force.
Effective limb length and the scaling of locomotor cost in terrestrial animals
Authors: Pontzer Herman
Published: May 2007

Relative to body size, smaller animals use more energy to travel a given distance than larger animals, but the anatomical variable driving this negative allometry remains the subject of debate. Here, I report a simple inverse relationship between effective limb length (i.e. hip height) and the energy cost of transport (COT; J kg–1 m–1)for terrestrial animals. Using published data for a diverse set of terrestrial species including birds, mammals, reptiles and arthropods, I show that between-species differences in locomotor cost are driven by differences in limb length. Notably, there is no independent effect of body mass on cost. Remarkably, effective limb length explains 98% of the observed variance in locomotor cost across a wide range of terrestrial species including mammals,birds, reptiles and arthropods. Variation about the limb-length/COT scaling relationship is attributable to taxonomic differences in limb design, with birds and arthropods exhibiting greater residuals than mammals. Differences in COT between semi-aquatic, generalist and cursorial species also corresponds to differences in leg length between these groups. These results are discussed in light of previous investigations of the limb length and locomotor cost.
Toll-Like Receptor 9 Ligand Blocks Osteoclast Differentiation Through Induction of Phosphatase
Authors: Amcheslavsky Alla , Bar-Shavit Zvi
Published: May 2007

CpG-ODN, in addition to stimulation of osteoclastogenic signals in early osteoclast precursors, also induces phosphatase, shifting the pattern of ERK phosphorylation from sustained to transient. This shift results in the degradation of c-fos, an essential molecule for osteoclast differentiation. Therefore, CpG-ODN blocks osteoclast differentiation.

Introduction: Activation of either Toll-like receptor 9 (TLR9) or RANK induces similar responses in osteoclast precursors. Paradoxically, activation of TLR9 results in inhibition of RANKL-induced osteoclastogenesis.

Materials and Methods: We used bone marrow—derived osteoclast precursors. Analyses of signaling molecules phosphorylation were performed using Western blotting. Different levels of gene expression analyses were performed using RT-PCR, Northern, and run-on analyses (for RNA), and EMSA, Western, and pulse-chase experiments (for protein). Phosphatase activity was measured spectrophotometrically.

Results: We found that RANKL and TLR9 ligand, oligodeoxynucleotides containing unmethylated CpG dinucleotides (CpG-ODN), induce sustained and transient extracellular signal-regulated kinase (ERK) phosphorylation, respectively. Furthermore, together they induce a transient phosphorylation of ERK. The duration of ERK phosphorylation is a key factor in determining induction of c-fos, a protein critical for osteoclastogenesis. Indeed, we found that CpG-ODN does not induce c-fos and inhibits its induction by RANKL by enhancing c-fos mRNA and protein degradation. Our observation that CpG-ODN, but not RANKL, induces the expression of the phosphatase PP2A suggests that CpG-ODN exerts its inhibitory activity by induction of ERK dephosphorylation. Moreover, together with the phosphatase inhibitor okadaic acid, CpG-ODN induces sustained ERK phosphorylation and c-fos expression.

Conclusions: Our findings suggest that the increased rate of c-fos degradation by the TLR9 ligand mediates the inhibition of RANKL-induced osteoclast differentiation. The TLR9 ligand, through induction of dephosphorylation, prevents the sustained ERK phosphorylation needed for maintaining high c-fos levels that are essential for osteoclast differentiation.
Krüppel-Like Zinc Finger Protein Glis3 Promotes Osteoblast Differentiation by Regulating FGF18 Expression
Authors: Beak Ju Youn , Kang Hong Soon , Kim Yong-Sik , Jetten Anton M
Published: May 2007

The zinc finger protein Glis3 is highly expressed in human osteoblasts and acts synergistically with BMP2 and Shh in enhancing osteoblast differentiation in multipotent C3H10T1/2 cells. This induction of osteoblast differentiation is at least in part caused by the induction of FGF18 expression. This study supports a regulatory role for Glis3 in osteoblast differentiation.

Introduction: Gli-similar 3 (Glis3) is closely related to members of the Gli subfamily of Krüppel-like zinc finger proteins, transcription factors that act downstream of sonic hedgehog (Shh). In this study, we analyzed the expression of Glis3 in human osteoblasts and mesenchymal stem cells (MSCs). Moreover, we examined the regulatory role of Glis3 in the differentiation of multipotent C3H10T1/2 cells into osteoblasts and adipocytes.

Materials and Methods: Microarray analysis was performed to identify genes regulated by Glis3 in multipotent C3H10T1/2 cells. Reporter and electrophoretic mobility shift assays were performed to analyze the regulation of fibroblast growth factor 18 (FGF18) by Glis3.

Results: Glis3 promotes osteoblast differentiation in C3H10T1/2 cells as indicated by the induction of alkaline phosphatase activity and increased expression of osteopontin, osteocalcin, and Runx2. In contrast, Glis3 expression inhibits adipocyte differentiation. Glis3 acts synergistically with BMP2 and Shh in inducing osteoblast differentiation. Deletion analysis indicated that the carboxyl-terminal activation function of Glis3 is needed for its stimulation of osteoblast differentiation. Glis3 is highly expressed in human osteoblasts and induced in MSCs during differentiation along the osteoblast lineage. Microarray analysis identified FGF18 as one of the genes induced by Glis3 in C3H10T1/2 cells. Promoter analysis and electrophoretic mobility shift assays indicated that a Glis3 binding site in the FGF18 promoter flanking region is important in its regulation by Glis3.

Conclusions: Our study showed that Glis3 positively regulates differentiation of C3H10T1/2 cells into osteoblasts and inhibits adipocyte differentiation. Glis3 acts synergistically with BMP2 and Shh in inducing osteoblast differentiation. The promotion of osteoblast differentiation by Glis3 involves increased expression of FGF18, a positive regulator of osteogenesis. This, in conjunction with the induction of Glis3 expression during osteoblast differentiation in MSCs and its expression in osteoblasts, suggests that Glis3 is an important modulator of MSC differentiation.
Sex Differences in Genetic and Environmental Factors Contributing to Body-Height
Authors: Silventoinen Karri , Kaprio Jaakko , Lahelma Eero , Viken Richard J. , Rose Richard J.
Published: May 2007

Sex differences in the heritability of self-reported body-height in two Finnish twin cohorts were studied by using sex-limitation models. The first cohort was born in 1938–1949 (N = 4873 twin pairs) and the second in 1975–1979 (N = 2374 twin pairs). Body-height was greater in the younger cohort (difference of 3.1 cm for men and 2.9 cm for women). The heritability estimates were higher among men (h2 = 0.87 in the older cohort and h2 = 0.82 in the younger cohort) than women (h2 = 0.78 and h2 = 0.67, respectively). Sex-specific genetic factors were not statistically significant in either cohort, suggesting that the same genes contribute to variation in body height for both men and women. The stronger contribution of environmental factors to body-height among women questions the hypothesis that women are better buffered against environmental stress, at least for this phenotype.
Phenotypic and Genetic Analyses of a Short Measure of Psychosis-proneness in a Large-scale Australian Twin Study
Authors: Hay David A. , Martin Nicholas G. , Foley Debra , Treloar Susan A. , Kirk Katherine M. , Heath Andrew C.
Published: May 2007

Previous genetic analyses of psychosis proneness have been limited by their small sample size. For the purposes of large-scale screening, a 12-item questionnaire was developed through a two-stage process of reduction from the full Chapman and Chapman scales. 3685 individuals (including 1438 complete twin pairs) aged 18–25 years and enrolled in the volunteer Australian Twin Registry returned a mail questionnaire which included this psychosis proneness scale and the Eysenck Personality Questionnaire. Despite the brevity of the questionnaire, item and factor analysis identified four unambiguous and essentially uncorrelated scales. There were (1) Perceptual Aberration – Magical Ideation; (2) Hypomania – Impulsivity/Nonconformity; (3) Social Anhedonia and (4) Physical Anhedonia. Model-fitting analyses showed additive genetic and specific environmental factors were sufficient for three of the four scales, with the Social Anhedonia scale requiring also a parameter for genetic dominance. There was no evidence for the previously hypothesised sex differences in the genetic determination of psychosis-proneness. The potential value of multivariate genetic analysis to examine the relationship between these four scales and dimensions of personality is discussed. The growing body of longitudinal evidence on psychosis-proneness suggests the value of incorporating this brief measure into developmental twin studies.
The Management and Outcome of Higher Order Multifetal Pregnancies: Obstetric, Neonatal and Follow-up Data
Authors: Yudin Mark H. , Asztalos Elizabeth V. , Jefferies Ann , Barrett Jon F.R.
Published: May 2007

The objective of this study was to describe current obstetric, neonatal, and long-term neurodevelopmental outcomes of higher order multifetal gestations (≥ 3 fetuses) in the 1990s. We also intended to identify a target gestational age at which neonatal and neurodevelopmental morbidities are low. Records from all multifetal pregnancies (≥ 3 viable fetuses ≥ 20 weeks gestation) delivered at the two perinatal centers in Toronto, Ontario, Canada during the study period (January 1, 1990–December 31, 1996) were reviewed. Data were collected on obstetric, neonatal, and long-term neurodevelopmental outcomes. Follow up data were gathered regarding the presence of a severe deficit in four categories (vision, hearing, cognition, and motor skills). Statistical analysis was performed to determine a gestational age at which a significant decrease in deficit occurred. During the study period 165 multifetal pregnancies were delivered. This resulted in 511 fetuses, of which 496 were live births. Of these 496 infants, 453 survived to discharge. Follow up data were obtained on 332 (73.3 per cent) infants. Infant survival increased with gestational age, and was approximately 90 per cent or greater at 26 weeks or more. Of all infants followed, the proportion of those without deficit increased with increasing gestational age, such that the per cent without deficit was 96.9 at 31 weeks or greater. Of all infants followed, 301 (90.7 per cent) had no deficit. Statistical analysis revealed a significant difference in long-term neurodevelopmental outcome between infants born before and after 28 weeks gestation. The incidence of a major deficit was 44.1 per cent for those born earlier than and 5.4 per cent for those born later than this gestational age (p= 0.001). In our cohort, survival figures were high. Even in lower gestational groupings, survival was high, but not without serious concerns about severe morbidity. This information is useful when counseling parents of higher order multifetal pregnancies.
Lipoprotein Candidate Genes for Multivariate Factors of the Insulin Resistance Syndrome: A Sib-pair Linkage Analysis in Women Twins
Authors: Edwards K.L. , Talmud P.J. , Newman B. , Krauss R.M. , Austin M.A.
Published: May 2007

The insulin resistance syndrome (IRS) is characterized by a combination of interrelated coronary heart disease risk factors, including low high-density lipoprotein cholesterol (HDLC) levels, obesity and increases in triglyceride (TG), systolic and diastolic blood pressure (BP), small low-density lipoprotein particles (LDL-size), and fasting and postload plasma insulin and glucose. Using factor analysis, we previously identified multivariate factors based on data from women participating in the Kaiser Permanente Women Twins Study: 1) Weight/Fat, 2) Insulin/Glucose, 3) Lipids, and 4) BP. The purpose of this study is to evaluate evidence for genetic linkage between the multivariate factors and candidate genes. Quantitative sib-pair analysis based on the factor scores with markers for 9 candidate genes was carried out based on data from 126 pairs of dizygotic (DZ) women twins from the second exam of the Kaiser Permanente Women Twins study. Suggestive evidence for linkage was found for the Weight/fat factor and the Apo E gene (p= 0.01), and stronger evidence for linkage with the Lipid factor and the cholesterol ester transfer protein (p= 0.002) gene. Therefore, the CETP gene appears to influence covariation in LDL size, TG, and HDL, and may account for a portion of the well-established statistical and metabolic associations observed between these risk factors.
An Integrative Approach for Studying the Etiology of Alcoholism and Other Addictions
Authors: Jacob T. , Sher K.J. , Bucholz K.K. , True W.T. , Sirevaag E.J. , Rohrbaugh J. , Nelson E. , Neuman R.J. , Todd R.D. , Slutske W.S. , Whitfield J.B. , Kirk K.M. , Martin N.G. , Madden P.A.F. , Heath A.C.
Published: May 2007

Studies of alcoholism etiology often focus on genetic or psy-chosocial approaches, but not both. Greater understanding of the etiology of alcohol, tobacco and other addictions will come from integration of these research traditions. A research approach is outlined to test three models for the etiology of addictions — behavioral undercontrol, pharmacologic vulnerability, negative affect regulation — addressing key questions including (i) mediators of genetic effects, (ii) genotype-environment correlation effects, (iii) genotype x environment interaction effects, (iv) the developmental unfolding of genetic and environmental effects, (v) subtyping including identification of distinct trajectories of substance involvement, (vi) identification of individual genes that contribute to risk, and (vii) the consequences of excessive use. By using coordinated research designs, including prospective assessment of adolescent twins and their siblings and parents; of adult substance dependent and control twins and their MZ and DZ cotwins, the spouses of these pairs, and their adolescent offspring; and of regular families; by selecting for gene-mapping approaches sibships screened for extreme concordance or discordance on quantitative indices of substance use; and by using experimental (drug challenge) as well as survey approaches, a number of key questions concerning addiction etiology can be addressed. We discuss complementary strengths and weaknesses of different sampling strategies, as well as methods to implement such an integrated approach illustrated for the study of alcoholism etiology. A coordinated program of twin and family studies will allow a comprehensive dissection of the interplay of genetic and environmental risk-factors in the etiology of alcoholism and other addictions.
Placentation in Multiple Births
Authors: Machin Geoffrey
Published: May 2007

Outcomes of multifetal pregnancy in prenatal life are markedly affected by chorionicity. Several disease processes are found in monochorionic (MC) twins that do not occur in dichorionic (DC) twins. Improvements in prenatal outcomes will depend on reliable first trimester diagnosis of chorionicity, allowing early monitoring for complications of MC placentation. Particular structures and functions of MC twin placentas affect outcomes and can be targeted for specific treatments, especially in twin-twin transfusion. The causes of severe DC twin fetal growth discordance are clarified. In post-natal life, zygosity is a determining effect in genetic predisposition to many chronic diseases, including neoplasia. Few MC twins know that they are monozygotic (MZ). Few twin researchers realize that MZ twins may be genetically discordant. Abandonment of the word “identical” for MZ twins would assist in clarifying these issues of zygosity, concordance and discordance.
Should all Twins be Delivered by Caesarean Section? A Preliminary Report
Authors: Rydhstroem Hakan
Published: May 2007

The aim was to analyse the neonatal mortality related to mode of delivery for twins using a population-based registry. In all, 18,125 twins delivered in Sweden between 1991 and 1997, after excluding those with unknown gestational duration, were used to analyse the differences between groups of twins. Results showed the OR for neonatal death, breech vaginal delivery versus caesarean section (all indications) was 1.47 (95% CI 0.99-2.17). The OR at vaginal delivery for neonatal death, twin I in breech versus cephalic presentation was 5.60 (2.62-11.94) and for twin II the corresponding figures were 1.85 (1.03-3.32). Analyses using population-based registries from other countries are needed to confirm or reject the present findings of an increased neonatal mortality for twins in breech presentation delivered vaginally.
Two Cases With Dichorionic Diamniotic Triplet Pregnancy and Early Cord Entanglement
Authors: Merién Ashley E.R. , van Eyck Jim , Arabin Birgit
Published: May 2007

Within a period of 6 years (1994–99) we registered 29 triplet deliveries out of a total of 13,969 hospital deliveries (0.02%). Since there is limited information about specific problems of chorionicity in triplet pregnancies, we analysed the 29 cases according to origin of pregnancy and chorionicity. We here report on two cases with a high risk according to chorionicity with dichorionic (DC) diamniotic (DA) triplet pregnancies. Out of the two cases, one pregnancy was spontaneous and one originated after in-vitro fertilization. In both pregnancies, cord entanglement was detected early in pregnancy (at 10 and 15 weeks) by color Doppler velocimetry demonstrating different heart rates within the segment of the entangled umbilical branches. The pregnancies were followed by documenting fetal behavior and color Doppler velocimetry of umbilical and fetal arteries at weekly intervals. In both cases, a primary Cesarean section was performed after detection of lung maturity. In the first case, one of the MA triplets had a transposition of the great arteries and abnormal lung vein drainage, which was the reason for neonatal death three weeks postnatally. Although early cord entanglement has been described in MA twins, this series demonstrates that it can as well be demonstrated in MA triplets. The early detection allows for extensive surveillance of the a priori high risk triplet pregnancy.
Gestational Duration, and Fetal and Infant Mortality for Twins vs Singletons
Authors: Rydhstroem Hakan , Heraib Fayez
Published: May 2007

The aim of this research was to study fetal and infant mortality in Sweden between 1973 and 1996 in twins vs singletons in relation to gestational duration. Analysis was of fetal and infant mortality based on the number of pregnancies at risk as the denominator rather than the number of deliveries each week. The analysis was based on information stored at the Medical Birth Registry (MBR), the National Board of Health and Welfare, Stockholm. The MBR keeps records on virtually all pregnancies (> 99%) regarding delivery and neonatal information, and for infant mortality up to 1 year of age. During the study period, 2,206,738 singleton and 52,658 twin births were registered. Risk evaluation was made as odds ratio (OR) with a 95% confidence interval. The material was stratified according to parity, maternal age, year of delivery, and delivery unit. Results showed the OR for twin births before 34 weeks gestation was 6 to 8-fold increased compared with singletons. The OR for fetal mortality was increased in all gestational weeks, and like-sexed twins had a consistently poorer prognosis compared to unlike-sexed. Between 1989–96, unlike-sexed twins had a fetal mortality approaching that of singletons. In conclusion, real progress in reduction of infant mortality in twins may be impossible until the high incidence of preterm births can be decreased. Hypothetically, about 100 twin labors would have to be induced to avoid one fetal death in like-sexed twin pregnancies.
Development and Representativeness of a Large Population-Based Cohort of Native Californian Twins
Authors: Cockburn Myles G. , Hamilton Ann S. , Zadnick John , Cozen Wendy , Mack Thomas M.
Published: May 2007

We have established a large cohort of twins to facilitate studies of the role of genetics and environment in the development of disease. The cohort has been derived from all multiple births occurring in California between 1908–82 (256,616 in total). We report here on our efforts to contact these twins and their completion of a detailed 16 page risk factor questionnaire. Addresses of the individuals were obtained by linking the birth records with the California Department of Motor Vehicles (DMV) roster of licensees. To date this has been completed for twins born between 1908 and 1972 (200,589 individuals). The linkage has revealed 112,468 matches and, because of less complete DMV records in some years, was less successful in older females than in younger females and all males. Over 41,000 twins have participated by completing the questionnaire. Based on estimates of numbers of individuals receiving a questionnaire, we estimate our crude response rate to be between 42.2% and 49.6%, highest among females in their 40s (62.8%). We describe the representativeness of the twins in the original birth cohort, those identified by the linkage, and those completing the questionnaire. Compared to the 1990 resident population of California-born resident singletons, the respondents were of similar age, sex, race and residential distribution (for although we were able to locate fewer older females, they had a higher response rate), but were less likely to have been educated for more than 12 years. We provide a brief synopsis of studies nested within this cohort. We also elucidate our plans for expanding the cohort in the near future.
The Heritability of Mortality Due to Heart Diseases: A Correlated Frailty Model Applied to Danish Twins
Authors: Wienke Andreas , Holm Niels V. , Skytthe Axel , Yashin Anatoli I.
Published: May 2007

Data of the Danish Twin Registry on monozygotic and dizygotic twins are used to analyse genetic and environmental influences on susceptibility to heart diseases for males and females, respectively. The sample includes 7955 like-sexed twin pairs born between 1870 and 1930. Follow-up was from 1 January 1943 to 31 December 1993 which results in truncation (twin pairs were included in the study if both individuals were still alive at the beginning of the follow-up) and censoring (nearly 40% of the study population was still alive at the end of the follow-up). We use the correlated gamma-frailty model for the genetic analysis of frailty to account for this censoring and truncation. During the follow-up 9370 deaths occurred, 3393 deaths were due to heart diseases in general, including 2476 deaths due to coronary heart disease (CHD). Proportions of variance of frailty attributable to genetic and environmental factors were analyzed using the structural equation model approach. Different standard biometric models are fitted to the data to evaluate the magnitude and nature of genetic and environmental factors on mortality. Using the best fitting model heritability of frailty (liability to death) was found to be 0.55 (0.07) and 0.53 (0.11) with respect to heart diseases and CHD, respectively, for males and 0.52 (0.10) and 0.58 (0.14) for females in a parametric analysis. A semi-parametric analysis shows very similar results. These analyses may indicate the existence of a strong genetic influence on individual frailty associated with mortality caused by heart diseases and CHD in both, males and females. The nature of genetic influences on frailty with respect to heart diseases and CHD is probably additive. No evidence for dominance and shared environment was found.
The Personalities of Twins: Just Ordinary Folks
Authors: Johnson Wendy , Krueger Robert F. , Bouchard Thomas J. , McGue Matt
Published: May 2007

Twin studies have demonstrated that personality traits show moderate genetic influence. The conclusions drawn from twin studies rely on the assumptions that twins are representative of the population at large and that monozygotic and dizygotic twins are comparable in every way that might have bearing on the traits being studied. To evaluate these assumptions, we used Multidimensional Personality Questionnaire (MPQ) data from three samples drawn from the Minnesota Twin Registry (totaling 12,971 respondents) to examine the effect sizes associated with mean differences on the 11 MPQ scales and 3 higher-order MPQ factors for singletons versus twins and MZ twins versus DZ twins. The singletons in the samples were family members of the participating twins. We also used ratios of scale variances to examine the significance of variance differences. The only mean or variance difference replicated across all three samples was greater Social Closeness (about .1 standard deviation) for twins than for singletons. This difference was obtained for both males and females. It would appear that, with respect to personality, twins are not systematically different from other people. Our results also highlight the importance of replication in psychological research because each of our large samples showed differences not replicated in other samples.
Confronting Unique Problems With Twins
Authors: Segal Nancy L.
Published: May 2007

Families with twins occasionally confront unique problems warranting considerable professional attention. The possibility that twins may be less likely to be admitted to private schools of their choice, due to reduced financial contributions from family members, was recently raised. Specifically, two twin children have two sets of grandparents, while two non-twin children have four sets of grandparents; thus, schools would profit more highly by admitting non-twins. This sets the stage for reviewing steps that some universities and businesses have taken to offset the financial burdens of rearing multiples. Next, a research review of four twin studies follows. Findings on gluten sensitivity, tremors, communicative adaptability and serological differences are summarized. A tour of a fascinating twin exhibit at the Teylers Museum, in the Netherlands, concludes this column.
Natural History of 11 Cases of Twin-twin Transfusion Syndrome Without Intervention
Authors: Gul Ahmet , Aslan Halil , Polat Ibrahim , Cebeci Altan , Bulut Hasan , Sahin Ozturk , Ceylan Yavuz
Published: May 2007

The natural history of 11 cases of twin–twin transfusion syndrome (TTTS) in monochorionic diamniotic (MCDA) twin pregnancies has been reviewed. Seven cases before 28 weeks and four pregnancies after 28 weeks had been followed up without intervention. Eight cases had premature uterine contractions. All seven pregnancies before 28 weeks aborted, leading to a 100% mortality rate. After 28 weeks all mothers delivered live births. The diagnosis of TTTS before 28 weeks, and with premature uterine contraction, seems to be a poor prognostic sign.
Has the “Equal Environments” Assumption Been Tested in Twin Studies?
Authors: Eaves Lindon , Foley Debra , Silberg Judy
Published: May 2007

Arecurring criticism of the twin method for quantifying genetic and environmental components of human differences is the necessity of the so-called “equal environments assumption” (EEA) (i.e., that monozygotic and dizygotic twins experience equally correlated environments). It has been proposed to test the EEA by stratifying twin correlations by indices of the amount of shared environment. However, relevant environments may also be influenced by genetic differences. We present a model for the role of genetic factors in niche selection by twins that may account for variation in indices of the shared twin environment (e.g., contact between members of twin pairs). Simulations reveal that stratification of twin correlations by amount of contact can yield spurious evidence of large shared environmental effects in some strata and even give false indications of genotype x environment interaction. The stratification approach to testing the equal environments assumption may be misleading and the results of such tests may actually be consistent with a simpler theory of the role of genetic factors in niche selection.
Defining Success in Multiple Birth
Authors: Hall Nina Keith , Keith Donald M.
Published: May 2007

Where you sit defines success in the world of multiple births. One person's success is a failure to others. Comments and observations come from years of working with parents of multiple clubs and presentations to and discussions with obstetricians and neonatologists.
Southern Green Revolution: Urban Environmental Activism in Kaohsiung, Taiwan
Authors: LEE ANRU
Published: May 2007

While the environmental movement in southern Taiwan exemplifies the recent worldwide trend of social movements with participants seeking local identity and autonomy in an increasingly global but deterritorialized world, it also has distinctive local characteristics derived from Taiwan's unique geo‐political history. In Taiwan, environmental movements were an integral part of the larger process of democratization. In their effort to create a cleaner and greener environment, green activists in Kaohsiung, the second largest city in Taiwan, set up examples of citizen participation and assisted in establishing within the existing administrative framework formal mechanisms for public involvement. More crucially, via the language of ecological conservation, they helped to create a powerful political discourse that not only fundamentally challenged the central government's legitimacy, but also forced the country to rethink and refashion the foundation of Taiwan's national identity that, in turn, aided the efforts of environmental preservation.
Morality, Cosmopolitanism, or Academic Attainment? Discourses on “Quality” and Urban Chinese‐Only‐Children's Claims to Ideal Personhood
Authors: FONG VANESSA L.
Published: May 2007

The term “quality” (suzhi) has become a ubiquitous part of Chinese popular discourses and the focus of Chinese educational campaigns. Amorphous, multivalent, and widely used, the term “high quality” represents a kind of ideal personhood associated with urban modernity. Based on 32 months of participant observation conducted in schools and homes in a Chinese city between 1997 and 2006, this paper examines how and why urban Chinese only‐children with various different strengths in morality, cosmopolitanism, and academic attainment chose, defended, and promoted definitions of quality that favored their own strengths.
Oral Versus High-Dose Pulse Corticosteroids for Problematic Infantile Hemangiomas: A Randomized, Controlled Trial
Authors: Pope Elena , Krafchik Bernice R. , Macarthur Colin , Stempak Diana , Stephens Derek , Weinstein Miriam , Ho Nhung , Baruchel Sylvain
Published: May 2007

OBJECTIVES. Oral systemic corticosteroids are the mainstay of treatment for problematic hemangiomas; however, current information is based on anecdotal experience and retrospective studies. We aimed to determine whether systemic steroids are efficacious in proliferating hemangioma and to compare the efficacy and safety of 2 corticosteroid treatment modalities.

PATIENTS AND METHODS. Twenty patients with problematic hemangiomas of infancy were randomly assigned to either daily oral prednisolone or monthly intravenous pulses of methylprednisolone. Their clinical outcomes (improvement using a visual analog score) and adverse events were compared at 3 months from baseline and 1 year of age. Data on possible surrogate markers of angiogenesis were available for the first 3 months.

RESULTS. At 3 months, orally treated patients had a median visual analog score of 70 compared with 12 in the intravenous group. This response pattern was similar at the patients' first birthday: 50.0 vs −1.5. Additional treatment beyond 3 months was needed for 65% of the patients (7 in the intravenous and 6 in the oral group). Six of 8 patients with impaired vision at enrollment had an improved function at 1 year (4 patients in the intravenous group and 3 patients in the oral group). Of the 4 surrogate markers of angiogenesis measured (plasma basic fibroblast growth factor, vascular endothelial growth factor, vascular cellular adhesion molecule 1, endoglin, and urine basic fibroblast growth factor), the only 2 that decreased over time were vascular cellular adhesion molecule 1 and endoglin. Patients in the oral group had a higher rate of adverse effects, such as hypertension (18.6% vs 13.1%), abnormal cortisol (78% vs 60%), and growth retardation.

CONCLUSIONS. Systemic corticosteroids are efficacious in stopping the proliferation of hemangiomas. The oral corticosteroids offered more clinical and biological benefit than the pulse steroids with higher risk of adverse effects.
Action Heroes and Literate Sidekicks: Literacy and Identity in Popular Culture
Authors: Williams Bronwyn T.
Published: May 2007

The question is not whether literacy practices are present in contemporary popular culture—it is hard not to find a movie or program without some representation of literacy in it. The more important and useful question is, How do we in the audience interpret the literacy practices we find in popular culture? What do such representations tell us about how we think of the ways that reading and writing construct our public identities? In the classroom, how do we encourage students to situate themselves in relationship to the identities they see portrayed in popular culture? Teachers need to help students think carefully about the myths and realities of literacy and consider whether their experiences and goals for reading and writing are similar to or different from the narratives about literacy that get repeated in popular culture.
What Can Video Games Teach Us About Teaching Reading?
Authors: Compton‐Lilly Catherine
Published: May 2007

James Gee has suggested that video games can teach us important lessons about learning and that we can learn about teaching from these games. Reading research and the words of the author's daughter are the basis of an exploration of the learning principles Gee identifies. He explains that video games are successful in engaging children and teaching them the strategies they need to be successful and that high‐quality reading instruction should do the same.

In this article, eight of the learning principles identified by Gee are applied to the teaching of reading. The first two explore insights about learners and the conditions that foster learning. The next three principles address general understandings about how learning occurs. The final three principles have direct implications for teaching.

The article raises important questions about learning, engagement, and identity, as well as promoting problem solving and strategic activity in reading.
Repeated Interactive Read‐Alouds in Preschool and Kindergarten
Authors: McGee Lea M. , Schickedanz Judith A.
Published: May 2007

Repeated interactive read‐alouds, a systematic method of reading aloud, allow teachers to scaffold children's understanding of the book being read, model strategies for making inferences and explanations, and teach vocabulary and concepts. A storybook is read three times in slightly different ways in order to increase the amount and quality of children's analytical talk as they answer carefully crafted questions. During the first reading, teachers introduce the story's problem, insert comments, ask a few key questions, and finally ask a “why” question calling for extended explanation. This is accompanied by elaborations on a few key vocabulary words. Second reads capitalize on children's growing comprehension of the story by providing enriched vocabulary explanations and asking additional inference and explanation questions. Third reads consist of guided reconstruction of the story in which children recount information as well as provide explanations and commentary.

These techniques have shown to be effective in increasing children's engagement, understanding, and appreciation of literature in preschool and kindergarten settings.
Helping Struggling Writers Succeed: A Self‐Regulated Strategy Instruction Program
Authors: Helsel Lisa , Greenberg Daphne
Published: May 2007

While writer's workshop provides a nurturing environment for many students, others struggle with the independence it gives. This may be due to the difficulty of coordinating the cognitive and self‐regulatory demands of the writing process. Self‐regulation refers to thoughts, feelings, and actions that individuals use to attain personal goals. Because of the independent nature of writing, an adequate level of self‐regulation is required to move through the process.

Teaching self‐regulatory strategies within the context of writing may enable students to develop and execute a plan of action independently, resulting in more independent writing. The Self‐Regulated Strategy Development model of instruction is one such strategy. In order to examine its impact, the model was used to teach a summary writing strategy to a struggling sixth grader. Following instruction, the student exhibited more confidence in her writing abilities, a greater belief in the benefits of strategy use, and the ability to tackle the writing task more independently.
Understanding mudslides through micro-seismic monitoring: the Super-Sauze (South-East French Alps) case study
Authors: Amitrano David , Gaffet Stéphane , Malet Jean-Philippe , Maquaire Olivier
Published: May 2007

The macroscopic deformation of rocks, at scales ranging from laboratory samples (cm) to rock hillslopes and earth crust (hm to km), is associated with local irreversible processes (cracks/faults propagation and shearing). These movements involve propagation of acoustic waves, which can be observed by remote sensing. Seismic monitoring during strain progression can help our understanding of rock behaviour and lead to the recognition of failure precursors. Although of significant potential, this observational tool has had only limited application in the study of gravitational instabilities such as landslides. This paper presents seismic monitoring data acquired on a mudslide located in the South French Alps. Results show that recordable seismicity exists in the frequency range of 0.01 Hz to 10 Hz associated with landslide deformation. Acceleration of landslide movement is controlled by rainfall and appears to be well correlated with seismic activity. The origin of the seismicity is attributed to shearing of the moving mass at the interface with the in-situ stable bedrock. Spectral analysis of the seismic wave reveals that the range 0.1–1 Hz is the most sensitive to the variations in landslide velocity. The results emphasize the strong potential of seismic monitoring for improving our understanding of mechanisms controlling rock mass deformation and gravitational instability. The determination of operational failure precursors based on seismic monitoring has yet to be achieved but remains a major target of future research.
Unstable rock slope hydrogeology: insights from the large-scale study of western Argentera-Mercantour hillslopes (South-East France)
Authors: Binet Stéphane , Guglielmi Yves , Bertrandet Catherine , Mudry Jacques
Published: May 2007

Inventory of unstable hillslopes, hydrogeological mapping and hydrochemical characteristics of natural spring waters were used to determine the long-term relationships between groundwater and gravitational instabilities in the Upper Tinée Valley (South-East French Alps). Water chemistry and flow records allow to propose a conceptual model of water flow within unstable rocky slopes and to back-calculate the volume of infiltrated water and the flow velocity in the aquifers for different deformation states of the slopes. An increase in infiltrated yield, flow velocity and porosity is observed and linked to collapsed and toppled structures in the upper parts of the hillslopes. In these areas, perched aquifers take place in the reworked media. When a large landslide occurs, it modifies the geometry of the slope and bypasses the perched flows down to the foot of the slope. With long-term continuous slope deformation, the associated effect between water flows and slope destabilization changes. In the fractured rock, the coupled effect corresponds to rising water pressures with limited volumes of infiltrated water; in the more fractured and permeable collapsed and toppled areas, the volumes of infiltrated water increase with a lower variation of water pressures.
Techniques, issues and advances in numerical modelling of landslide hazard
Authors: van Asch Theodore W.J. , Malet Jean-Philippe , van Beek Ludovicus P.H. , Amitrano David
Published: May 2007

Slope movements (e.g. landslides) are dynamic systems that are complex in time and space and closely linked to both inherited and current preparatory and triggering controls. It is not yet possible to assess in all cases conditions for failure, reactivation and rapid surges and successfully simulate their transient and multi-dimensional behaviour and development, although considerable progress has been made in isolating many of the key variables and elementary mechanisms and to include them in physically-based models for landslide hazard assessments. Therefore, the objective of this paper is to review the state-of-the-art in the understanding of landslide processes and to identify some pressing challenges for the development of our modelling capabilities in the forthcoming years for hazard assessment. This paper focuses on the special nature of slope movements and the difficulties related to simulating their complex time-dependent behaviour in mathematical, physically-based models. It analyses successively the research frontiers in the recognition of first-time failures (pre-failure and failure stages), reactivation and the catastrophic transition to rapid gravitational processes (post-failure stage). Subsequently, the paper discusses avenues to transfer local knowledge on landslide activity to landslide hazard forecasts on regional scales and ends with an outline how geomorphological investigations and supporting monitoring techniques could be applied to improve the theoretical concepts and the modelling performance of physically-based landslide models at different spatial and temporal scales.