Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 28
Filtrar
1.
Biotechnol Bioeng ; 117(10): 3160-3172, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32619017

RESUMO

Tissue constructs of physiologically relevant scale require a vascular system to maintain cell viability. However, in vitro vascularization of engineered tissues is still a major challenge. Successful approaches are based on a feeder layer (FL) to support vascularization. Here, we investigated whether the supporting effect on the self-assembled formation of prevascular-like structures by microvascular endothelial cells (mvECs) originates from the FL itself or from its extracellular matrix (ECM). Therefore, we compared the influence of ECM, either derived from adipose-derived stem cells (ASCs) or adipogenically differentiated ASCs, with the classical cell-based FL. All cell-derived ECM (cdECM) substrates enabled mvEC growth with high viability. Prevascular-like structures were visualized by immunofluorescence staining of endothelial surface protein CD31 and could be observed on all cdECM and FL substrates but not on control substrate collagen I. On adipogenically differentiated ECM, longer and higher branched structures could be found compared with stem cell cdECM. An increased concentration of proangiogenic factors was found in cdECM substrates and FL approaches compared with controls. Finally, the expression of proteins associated with tube formation (E-selectin and thrombomodulin) was confirmed. These results highlight cdECM as promising biomaterial for adipose tissue engineering by inducing the spontaneous formation of prevascular-like structures by mvECs.


Assuntos
Tecido Adiposo/citologia , Materiais Biocompatíveis/química , Células Endoteliais/citologia , Matriz Extracelular/química , Células-Tronco/citologia , Tecido Adiposo/irrigação sanguínea , Diferenciação Celular/fisiologia , Células Cultivadas , Matriz Extracelular/metabolismo , Humanos , Neovascularização Fisiológica
2.
Child Dev ; 90(4): 1185-1201, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-29171007

RESUMO

Effects of full-time ability grouping on students' academic self-concept (ASC) and mathematics achievement were investigated in the first 3 years of secondary school (four waves of measurement; students' average age at first wave: 10.5 years). Students were primarily from middle and upper class families living in southern Germany. The study sample comprised 148 (60% male) students from 14 gifted classes and 148 (57% male) students from 25 regular classes (matched by propensity score matching). Data analyses involved multilevel and latent growth curve analyses. Findings revealed no evidence for contrast effects of class-average achievement or assimilation effects of class type on students' ASC. ASC remained stable over time. Students in gifted classes showed higher achievement gains than students in regular classes.


Assuntos
Sucesso Acadêmico , Currículo , Inteligência , Matemática/educação , Autoimagem , Estudantes/psicologia , Adolescente , Criança , Feminino , Alemanha , Humanos , Masculino , Instituições Acadêmicas
3.
J Water Health ; 17(6): 870-883, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31850895

RESUMO

The World Health Organization (WHO) promotes water safety plans (WSPs) - a risk-based management approach - for premise plumbing systems in buildings to prevent deterioration of drinking-water quality. Experience with the implementation of WSPs in buildings were gathered within a pilot project in Germany. The project included an evaluation of the feasibility and advantages of WSPs by all stakeholders who share responsibility in drinking-water safety. While the feasibility of the concept was demonstrated for all buildings, benefits reported by building operators varied. The more technical standards were complied with before implementing WSP, the less pronounced were the resulting improvements. In most cases, WSPs yielded an increased system knowledge and awareness for drinking-water quality issues. WSPs also led to improved operation of the premise plumbing system and provided benefits for surveillance authorities. A survey among the European Network of Drinking-Water Regulators on the existing legal framework regarding drinking-water safety in buildings exhibited that countries are aware of the need to manage risks in buildings' installations, but experience with WSP is rare. Based on the successful implementation and the positive effects of WSPs on drinking-water quality, we recommend the establishment of legal frameworks that require WSPs for priority buildings whilst accounting for differing conditions in buildings and countries.


Assuntos
Água Potável/normas , Qualidade da Água , Abastecimento de Água/normas , Alemanha , Humanos , Projetos Piloto , Medição de Risco , Gestão de Riscos
4.
Diabetologia ; 57(6): 1192-8, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24671273

RESUMO

AIMS/HYPOTHESIS: Fetal programming plays an important role in the pathogenesis of type 2 diabetes. The aim of the present study was to investigate whether maternal metabolic changes during OGTT influence fetal brain activity. METHODS: Thirteen healthy pregnant women underwent an OGTT (75 g). Insulin sensitivity was determined by glucose and insulin measurements at 0, 60 and 120 min. At each time point, fetal auditory evoked fields were recorded with a fetal magnetoencephalographic device and response latencies were determined. RESULTS: Maternal insulin increased from a fasting level of 67 ± 25 pmol/l (mean ± SD) to 918 ± 492 pmol/l 60 min after glucose ingestion and glucose levels increased from 4.4 ± 0.3 to 7.4 ± 1.1 mmol/l. Over the same time period, fetal response latencies decreased from 297 ± 99 to 235 ± 84 ms (p = 0.01) and then remained stable until 120 min (235 ± 84 vs 251 ± 91 ms, p = 0.39). There was a negative correlation between maternal insulin sensitivity and fetal response latencies 60 min after glucose ingestion (r = 0.68, p = 0.02). After a median split of the group based on maternal insulin sensitivity, fetuses of insulin-resistant mothers showed a slower response to auditory stimuli (283 ± 79 ms) than those of insulin-sensitive mothers (178 ± 46 ms, p = 0.03). CONCLUSIONS/INTERPRETATION: Lower maternal insulin sensitivity is associated with slower fetal brain responses. These findings provide the first evidence of a direct effect of maternal metabolism on fetal brain activity and suggest that central insulin resistance may be programmed during fetal development.


Assuntos
Glicemia/fisiologia , Encéfalo/embriologia , Encéfalo/metabolismo , Insulina/metabolismo , Adulto , Feminino , Teste de Tolerância a Glucose , Humanos , Resistência à Insulina/fisiologia , Gravidez
5.
J Perinat Med ; 42(3): 307-14, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24225124

RESUMO

AIMS: Fetal behavioral states can be distinguished by biomagnetic recordings. We performed a longitudinal and a cross-sectional study to address the question whether the distribution of fetal behavioral states changes during the daytime. METHODS: For the longitudinal study, 32 magnetocardiographic recordings were performed on a singleton pregnancy on a weekly basis. On each examination day, two recordings were performed at different times between 25 and 40 weeks of gestation. For the cross-sectional study, fetal magnetocardiograms (fMCG) were recorded in a group of 32 singleton pregnancies matched for gestational age and daytime to the longitudinal study. The recordings were separated into two gestational age groups (less and more than 32 weeks). Fetal behavioral states were extracted from actocardiograms generated from MCG. RESULTS: No significant differences in fetal behavioral state distribution were found between morning and afternoon recordings in either the longitudinal or the cross-sectional study. CONCLUSION: This is the first magnetographic approach to show that daytime does not influence the distribution of fetal behavioral states in standardized recordings of 30 min length. This result implies that fetal magnetography recordings at normal daytimes can be combined without a bias and future recordings can be conducted independently of daytime as long as the varying behavioral states are generally taken into account during analysis.


Assuntos
Comportamento , Feto/fisiologia , Gravidez/fisiologia , Adulto , Estudos Transversais , Feminino , Humanos , Estudos Longitudinais , Magnetometria , Adulto Jovem
6.
Dev Sci ; 16(2): 287-295, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23432837

RESUMO

Habituation--the most basic form of learning--is used to evaluate central nervous system (CNS) maturation and to detect abnormalities in fetal brain development. In the current study, habituation, stimulus specificity and dishabituation of auditory evoked responses were measured in fetuses and newborns using fetal magnetoencephalography (fMEG). An auditory habituation paradigm consisting of 100 trains of five 500 Hz tones, one 750 Hz tone (dishabituator) and two more 500 Hz tones, respectively, were presented to 41 fetuses (gestational age 30-39 weeks) and 22 newborns or babies (age 6-89 days). A response decrement between the first and fifth tones (habituation), an increment between the fifth tone and the dishabituator (stimulus specificity) and an increment between the fifth (last tone before the dishabituator) and seventh tones (first tone after the dishabituator) (dishabituation) were expected. Fetuses showed weak responses to the first tone. However, a significant response decrement between the second and fifth tones (habituation) and a significant increment between the fifth tone and the dishabituator (stimulus specificity) were found. No significant difference was found for dishabituation nor was a developmental trend found at the group level. From the neonatal data, significant values for stimulus specificity were found. Sensory fatigue or adaptation was ruled out as a reason for the response decrement due to the strong reactions to the dishabituator. Taken together, the current study used fMEG to directly show fetal habituation and provides evidence of fetal learning in the last trimester of pregnancy.


Assuntos
Potenciais Evocados Auditivos/fisiologia , Habituação Psicofisiológica/fisiologia , Magnetoencefalografia/métodos , Estimulação Acústica , Feminino , Desenvolvimento Fetal , Monitorização Fetal/métodos , Feto/fisiologia , Idade Gestacional , Humanos , Lactente , Recém-Nascido , Gravidez , Terceiro Trimestre da Gravidez , Reprodutibilidade dos Testes , Processamento de Sinais Assistido por Computador
7.
J Perinat Med ; 41(5): 605-12, 2013 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-23612694

RESUMO

AIM: Fetal magnetography enables the recording of biomagnetic fetal signals, including fetal heart and fetal brain signals. These signals allow the determination of fetal behavioral states and functional brain signals with auditory evoked responses (AER). In the current study, we investigated how the behavioral state influences the AER and how stimulation affects fetal state. METHODS: One hundred and four fetuses in three age groups (28-31 weeks, 32-35 weeks and 36-41 weeks) were recorded with and without auditory stimulation. Both sessions were scored for fetal states. The AER latency was determined for each state separately. Forty-five additional subjects were recorded with two sessions of 10 min without stimulation to investigate a possible time effect on state changes. RESULTS: The state distribution was significantly different between stimulation and no stimulation conditions. The AER latencies were significantly shorter in active sleep (P=0.013) and active wakefulness (P=0.004) compared to quiet sleep. CONCLUSION: Auditory stimulation has an effect on fetal states. The state information should be taken into account for the analysis of AER latencies.


Assuntos
Encéfalo/fisiologia , Feto/fisiologia , Estimulação Acústica , Comportamento/fisiologia , Potenciais Evocados Auditivos , Feminino , Movimento Fetal/fisiologia , Neuroimagem Funcional/métodos , Idade Gestacional , Frequência Cardíaca/fisiologia , Humanos , Magnetometria/métodos , Masculino , Gravidez , Sono/fisiologia
8.
Biofabrication ; 16(1)2023 10 11.
Artigo em Inglês | MEDLINE | ID: mdl-37769669

RESUMO

The outcome of three-dimensional (3D) bioprinting heavily depends, amongst others, on the interaction between the developed bioink, the printing process, and the printing equipment. However, if this interplay is ensured, bioprinting promises unmatched possibilities in the health care area. To pave the way for comparing newly developed biomaterials, clinical studies, and medical applications (i.e. printed organs, patient-specific tissues), there is a great need for standardization of manufacturing methods in order to enable technology transfers. Despite the importance of such standardization, there is currently a tremendous lack of empirical data that examines the reproducibility and robustness of production in more than one location at a time. In this work, we present data derived from a round robin test for extrusion-based 3D printing performance comprising 12 different academic laboratories throughout Germany and analyze the respective prints using automated image analysis (IA) in three independent academic groups. The fabrication of objects from polymer solutions was standardized as much as currently possible to allow studying the comparability of results from different laboratories. This study has led to the conclusion that current standardization conditions still leave room for the intervention of operators due to missing automation of the equipment. This affects significantly the reproducibility and comparability of bioprinting experiments in multiple laboratories. Nevertheless, automated IA proved to be a suitable methodology for quality assurance as three independently developed workflows achieved similar results. Moreover, the extracted data describing geometric features showed how the function of printers affects the quality of the printed object. A significant step toward standardization of the process was made as an infrastructure for distribution of material and methods, as well as for data transfer and storage was successfully established.


Assuntos
Bioimpressão , Humanos , Bioimpressão/métodos , Reprodutibilidade dos Testes , Alicerces Teciduais/química , Materiais Biocompatíveis , Impressão Tridimensional , Engenharia Tecidual/métodos
9.
Clin Dev Immunol ; 2012: 432176, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23320018

RESUMO

BACKGROUND: The presence of anti-SSA/Ro and anti-SSB/La antibodies during pregnancy is associated with fetal congenital heart block (CHB), which is primarily diagnosed through fetal echocardiography. Conclusive information about the complete electrophysiology of the fetal cardiac conducting system is still lacking. In addition to echocardiography, fetal magnetocardiography (fMCG) can be used. fMCG is the magnetic analogue of the fetal electrocardiogram (ECG). PATIENTS AND METHODS: Forty-eight pregnant women were enrolled in an observational study; 16 of them tested positive for anti-SSA/Ro and anti-SSB/La antibodies. In addition to routine fetal echocardiography, fMCG was used. Fetal cardiac time intervals (fCTIs) were extracted from the magnetic recordings by predefined procedures. ECGs in the neonates of the study group were performed within the first month after delivery. RESULTS: The PQ segment of the fCTI was significantly prolonged in the study group (P = 0.007), representing a delay of the electrical impulse in the atrioventricular (AV) node. Other fCTIs were within normal range. None of the anti-SSA/Ro and/or anti-SSB/La fetuses progressed to a more advanced heart block during pregnancy or after birth. CONCLUSION: The study identified a low-risk population within antibody positive mothers, where PQ segment prolongation is associated with a lack of progression of the disease.


Assuntos
Anticorpos Antinucleares/imunologia , Nó Atrioventricular/embriologia , Nó Atrioventricular/patologia , Feto/imunologia , Feto/patologia , Adulto , Nó Atrioventricular/imunologia , Estudos de Casos e Controles , Ecocardiografia/métodos , Eletrocardiografia/métodos , Feminino , Bloqueio Cardíaco/congênito , Bloqueio Cardíaco/diagnóstico , Bloqueio Cardíaco/imunologia , Bloqueio Cardíaco/patologia , Humanos , Magnetocardiografia/métodos , Pessoa de Meia-Idade , Gravidez , Diagnóstico Pré-Natal , Adulto Jovem
10.
J Perinat Med ; 40(3): 277-86, 2012 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-22505507

RESUMO

Cardiotocography and echocardiography are currently standard for fetal heart monitoring. However, both do not provide adequate temporal resolution to measure fetal cardiac time intervals and detect arrhythmias, which can occur during normal sinus rhythm. Fetal magnetocardiography (fMCG) is a non-invasive technique measuring magnetic signals generated by fetal heart activity. Most fMCG devices are installed in research institutions limiting the implementation of this method in a clinical setting. Several institutions made a step forward by installing devices, in particular for fetal investigations, in hospital sites to evaluate the clinical benefit. Based on instrumentation differences which can affect signal quality, there is still no established reference database for fetal cardiac time intervals. A new magnetograph dedicated to fetal recordings was implemented with improved patient comfort. The setting was optimized to establish a standard. A total of 103 healthy fetuses starting as early as possible after the first trimester were recorded and fMCG values of cardiac time intervals were compared to former studies. Data allowed high and reliable detection for all fMCG components starting at 17 weeks. The data were comparable to fMCG multicenter studies, fetal electrocardiography and neonatal ECG results and could serve as a database of norm values for further investigation of fetal arrhythmias.


Assuntos
Monitorização Fetal/métodos , Magnetocardiografia/métodos , Diagnóstico Pré-Natal/métodos , Arritmias Cardíacas/congênito , Arritmias Cardíacas/diagnóstico , Interpretação Estatística de Dados , Feminino , Doenças Fetais/diagnóstico , Monitorização Fetal/instrumentação , Monitorização Fetal/normas , Monitorização Fetal/estatística & dados numéricos , Idade Gestacional , Frequência Cardíaca Fetal , Humanos , Magnetismo , Magnetocardiografia/instrumentação , Magnetocardiografia/normas , Magnetocardiografia/estatística & dados numéricos , Gravidez , Diagnóstico Pré-Natal/instrumentação , Diagnóstico Pré-Natal/normas , Diagnóstico Pré-Natal/estatística & dados numéricos , Valores de Referência
11.
PLoS One ; 17(7): e0271289, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35816496

RESUMO

The Internal-External Locus of Control Short Scale-4 (IE-4) measures two dimensions of the personality trait locus of control with two items each. IE-4 was originally developed and validated in German and later translated into English. In the present study, we assessed the psychometric properties (i.e., objectivity, reliability, validity) of the English-language IE-4, compared these psychometric properties with those of the German-language source version, and tested measurement invariance across both language versions. Using heterogeneous quota samples from the UK and Germany, we find that the English-language adaptation has satisfactory reliability and plausible correlations with 11 external variables (e.g., general self-efficacy, self-esteem, impulsive behavior, Emotional Stability), which are comparable with those of the German-language source version. Moreover, metric measurement invariance of the scale holds when comparing the UK and Germany, implying the comparability of correlations based on the latent factors across the two nations. As an ultra-short scale (completion time < 30 s), IE-4 lends itself particularly to the assessment of locus of control in survey contexts in which assessment time or questionnaire space are limited. It can be applied in a variety of research disciplines, such as psychology, sociology, or economics.


Assuntos
Controle Interno-Externo , Idioma , Alemanha , Psicometria/métodos , Reprodutibilidade dos Testes , Inquéritos e Questionários
12.
ACS Appl Mater Interfaces ; 14(27): 30455-30465, 2022 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-35777738

RESUMO

3D bioprinting is an emerging biofabrication strategy using bioinks, comprising cells and biocompatible materials, to produce functional tissue models. Despite progress in building increasingly complex objects, biological analyses in printed constructs remain challenging. Especially, methods that allow non-invasive and non-destructive evaluation of embedded cells are largely missing. Here, we implemented Raman imaging for molecular-sensitive investigations on bioprinted objects. Different aspects such as culture formats (2D, 3D-cast, and 3D-printed), cell types (endothelial cells and fibroblasts), and the selection of the biopolymer (alginate, alginate/nanofibrillated cellulose, alginate/gelatin) were considered and evaluated. Raman imaging allowed for marker-independent identification and localization of subcellular components against the surrounding biomaterial background. Furthermore, single-cell analysis of spectral signatures, performed by multivariate analysis, demonstrated discrimination between endothelial cells and fibroblasts and identified cellular features influenced by the bioprinting process. In summary, Raman imaging was successfully established to analyze cells in 3D culture in situ and evaluate them with regard to the localization of different cell types and their molecular phenotype as a valuable tool for quality control of bioprinted objects.


Assuntos
Bioimpressão , Tinta , Alginatos , Bioimpressão/métodos , Células Endoteliais , Hidrogéis/química , Impressão Tridimensional , Engenharia Tecidual/métodos , Alicerces Teciduais/química
13.
Langmuir ; 26(11): 7953-61, 2010 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-20146490

RESUMO

Active materials that can solubilize in different compartments of a sample show release properties which might be of interest in some applications where a delayed release of solutes for instance is required. We studied perfume solutes in compartments of Pluronic block copolymers of different compositions and molecular weights over a range of ethanol-water mixtures. Phase diagrams were constructed to identify and map micellar phases, then dynamic light scattering was used to characterize the solute-swollen micelles; NMR provided with the partition of solutes between solvent and micelles, and equilibrium constants K(c) were estimated using headspace analysis. Finally solute-evaporation rates were measured by thermogravimetry. We focused on two typical behaviors: when solubilization in a micellar compartment occurs, delayed release increased with K(c). When solubilization was limited or absent, either because no micelles form or, in the presence of micelles, because solubilization was minor or absent, delayed release was correspondingly absent.

14.
Dev Psychol ; 56(4): 795-814, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32052983

RESUMO

Adolescence is important for the development of achievement motivation, including achievement goal pursuit. Longitudinal research is scarce on adolescents' goal development and its implications for academic outcomes. In our research, we first present a systematic review of findings on achievement goals in adolescence. Then we report 2 longitudinal studies with German adolescents in which we investigated the separate as well as joint development of achievement goals, interest, and achievement in the domain of mathematics. Study 1 comprised 745 students assessed in 4 waves in grades 5-7 (43% female; age MT1 = 10.66). Study 2 comprised 1,420 students assessed in 4 waves in grades 5-8 (47% female; age MT1 = 10.58). Students reported their mastery, performance-approach, and performance-avoidance goals and their interest in mathematics. Mathematics achievement was assessed by school grades (Studies 1 and 2) and standardized test scores (Study 1). Data were analyzed using latent growth curve, multiple process, and cross-lagged models. Findings for the 2 studies evidenced a substantial degree of consistency. All goals decreased and the decrease became smaller over time in most instances. Controlling for nonfocal goals and demographic variables (socioeconomic status, gender), multiple process models revealed that change in mastery and performance-approach goals was positively related or unrelated to change in interest and achievement, whereas change in performance-avoidance goals was negatively related or unrelated to change in interest and achievement. Cross-lagged models revealed that relations between the achievement goals on the one hand and interest and achievement on the other hand were reciprocal rather than unidirectional. (PsycINFO Database Record (c) 2020 APA, all rights reserved).


Assuntos
Sucesso Acadêmico , Logro , Desenvolvimento do Adolescente/fisiologia , Desenvolvimento Infantil/fisiologia , Objetivos , Adolescente , Criança , Feminino , Humanos , Estudos Longitudinais , Masculino
15.
Obesity (Silver Spring) ; 28(1): 114-121, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31858736

RESUMO

OBJECTIVE: Prepregnancy obesity and extensive weight gain can lead to diseases in the offspring later in life. The aim of this study was to evaluate the effect of anthropometric and metabolic factors on the fetal autonomic nervous system (ANS) in uncomplicated pregnancies. METHODS: A total of 184 pregnant women in the second or third trimester were included, and for 104 women, maternal insulin sensitivity (ISI) was determined. Fetal heart rate (HR) and heart rate variability (HRV) were determined by magnetic recording. Associations of maternal prepregnancy BMI, weight gain, and ISI with fetal HR and HRV were evaluated by ANCOVA, partial correlation, and mediation analysis. RESULTS: HR was increased and HRV decreased in fetuses of mothers with overweight or obesity in comparison to normal-weight mothers. Fetal HR was negatively correlated with maternal weight gain. Maternal prepregnancy BMI was positively correlated with fetal high frequency and was negatively correlated with low frequency and low/high frequency ratio. Maternal ISI showed a negative correlation with fetal HR. CONCLUSIONS: The results show that the fetal ANS is sensitive to alterations of prepregnancy BMI, weight changes, and glucose metabolism. These findings highlight the importance of the intrauterine environment on the developing ANS and the possible programming of obesity.


Assuntos
Frequência Cardíaca Fetal/fisiologia , Metabolismo/fisiologia , Obesidade/complicações , Aumento de Peso/fisiologia , Adulto , Feminino , Humanos , Pessoa de Meia-Idade , Gravidez , Adulto Jovem
16.
Br J Educ Psychol ; 88(4): 513-528, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29131322

RESUMO

BACKGROUND: Achievement in math and achievement in verbal school subjects are more strongly correlated than the respective academic self-concepts. The internal/external frame of reference model (I/E model; Marsh, 1986, Am. Educ. Res. J., 23, 129) explains this finding by social and dimensional comparison processes. We investigated a key assumption of the model that dimensional comparisons mainly depend on the difference in achievement between subjects. We compared correlations between subject-specific self-concepts of groups of elementary and secondary school students with or without achievement differences in the respective subjects. AIMS: The main goals were (1) to show that effects of dimensional comparisons depend to a large degree on the existence of achievement differences between subjects, (2) to demonstrate the generalizability of findings over different grade levels and self-concept scales, and (3) to test a rarely used correlation comparison approach (CCA) for the investigation of I/E model assumptions. SAMPLES: We analysed eight German elementary and secondary school student samples (grades 3-8) from three independent studies (Ns 326-878). METHOD: Correlations between math and German self-concepts of students with identical grades in the respective subjects were compared with the correlation of self-concepts of students having different grades using Fisher's Z test for independent samples. RESULTS: In all samples, correlations between math self-concept and German self-concept were higher for students having identical grades than for students having different grades. Differences in median correlations had small effect sizes for elementary school students and moderate effect sizes for secondary school students. CONCLUSIONS: Findings generalized over grades and indicated a developmental aspect in self-concept formation. The CCA complements investigations within I/E-research.


Assuntos
Sucesso Acadêmico , Desenvolvimento do Adolescente , Desenvolvimento Infantil , Matemática , Autoimagem , Estudantes , Adolescente , Criança , Feminino , Humanos , Masculino , Estudantes/psicologia
17.
Front Physiol ; 9: 1278, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30283344

RESUMO

Intrauterine growth restriction (IUGR), which is already known to be a risk factor for pathological intrauterine development, perinatal mortality, and morbidity, is now also assumed to cause both physical and cognitive alterations in later child development. In the current study, effects of IUGR on infantile brain function were investigated during the fetal period and in a follow-up developmental assessment during early childhood. During the fetal period, visual and auditory event-related responses (VER and AER) were recorded using fetal magnetoencephalography (fMEG). VER latencies were analyzed in 73 fetuses (14 IUGR fetuses) while AER latencies were analyzed in 66 fetuses (11 IUGR fetuses). Bayley Scales of Infant Development, Second Edition (BSID-II) were used to assess the developmental status of the infants at the age of 24 months. The Mental Development Index (MDI) was available from 66 children (8 IUGR fetuses) and the Psychomotor Development Index (PDI) from 63 children (7 IUGR fetuses). Latencies to visual stimulation were more delayed in IUGR than in small for gestational age (SGA) or appropriate for gestational age (AGA) fetuses, albeit not to any significant extent (p = 0.282). The MDI in former IUGR infants was significantly lower (p = 0.044) than in former SGA and AGA infants. However, IUGR had no impact on PDI (p = 0.213). These findings support the hypothesis that IUGR may constitute a risk factor for neurodevelopmental delay. Further investigation of the possible underlying mechanisms, as well as continued long-term developmental research, is therefore necessary.

18.
PLoS One ; 12(5): e0177854, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28542384

RESUMO

Academic self-concept (ASC) is comprised of individual perceptions of one's own academic ability. In a cross-sectional quasi-representative sample of 3,779 German elementary school children in grades 1 to 4, we investigated (a) the structure of ASC, (b) ASC profile formation, an aspect of differentiation that is reflected in lower correlations between domain-specific ASCs with increasing grade level, (c) the impact of (internal) dimensional comparisons of one's own ability in different school subjects for profile formation of ASC, and (d) the role played by differences in school grades between subjects for these dimensional comparisons. The nested Marsh/Shavelson model, with general ASC at the apex and math, writing, and reading ASC as specific factors nested under general ASC fitted the data at all grade levels. A first-order factor model with math, writing, reading, and general ASCs as correlated factors provided a good fit, too. ASC profile formation became apparent during the first two to three years of school. Dimensional comparisons across subjects contributed to ASC profile formation. School grades enhanced these comparisons, especially when achievement profiles were uneven. In part, findings depended on the assumed structural model of ASCs. Implications for further research are discussed with special regard to factors influencing and moderating dimensional comparisons.


Assuntos
Logro , Instituições Acadêmicas , Autoimagem , Estudantes/psicologia , Criança , Estudos Transversais , Feminino , Humanos , Masculino
19.
Br J Educ Psychol ; 86(2): 222-40, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26689607

RESUMO

BACKGROUND: Ability grouping can lower students' academic self-perceptions through reference group effects of class-average achievement on academic self-concept (ASC) - the Big-fish-little-Pond-effect (BFLPE; Marsh & Parker, 1984, J. Pers. Soc. Psychol., 47, 213). Although the effect itself is well documented, many open questions remain. For instance, negative contrast effects of group average achievement and positive assimilation effects of group status are confounded in most BFLPE studies. For the verbal domain, no study has yet investigated contrast and assimilation effects simultaneously. Strong assimilation effects can be assumed for gifted ability grouping. AIMS: We aimed at disentangling contrast and assimilation effects of full-time within-school gifted tracking on verbal ASC and math ASC. SAMPLE: Students attended regular or gifted classes within the top track of German secondary schools. Our sample comprised 1,330 fifth-grade students (42 regular classes, n = 1,069, 48% female; 15 gifted classes, n = 261, 39% female). METHODS: Using multilevel regression analyses, we simultaneously modelled negative contrast effects of class ability and positive assimilation effects of class type (regular vs. gifted) on ASC in math and the verbal domain. RESULTS AND CONCLUSIONS: In the mathematical domain, the assimilation effect, caused by membership in gifted classes, compensated for negative contrast effects of class-average achievement on ASC even after controlling for previous ASC. In the verbal domain, we found neither a significant contrast effect nor an assimilation effect. Implications for gifted education are discussed.


Assuntos
Aptidão/fisiologia , Criança Superdotada/psicologia , Processos Grupais , Idioma , Matemática , Autoimagem , Logro , Criança , Feminino , Humanos , Masculino , Instituições Acadêmicas
20.
Early Hum Dev ; 100: 61-6, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27423115

RESUMO

BACKGROUND: Habituation, as a basic form of learning, is characterized by decreasing amplitudes of neuronal reaction following repeated stimuli. Recent studies indicate that habituation to pure tones of different frequencies occurs in fetuses and infants. AIMS: Neural processing of different syllables in fetuses and infants was investigated. STUDY DESIGN: An auditory habituation paradigm including two different sequences of syllables was presented to each subject. Each sequence consisted of eight syllables (sequence /ba/: 5× /ba/, 1× /bi/ (dishabituator), 2× /ba/; sequence /bi/: 5× /bi/, 1× /ba/ (dishabituator), 2× /bi/). Each subject was stimulated with 140 sequences. Neuromagnetic signatures of auditory-evoked responses (AER) were recorded by fetal magnetoencephalography (fMEG). SUBJECTS: Magnetic brain signals of N=30 fetuses (age: 28-39weeks of gestation) and N=28 infants (age: 0-3months) were recorded. Forty-two of the 60 fetal recordings and 29 of the 58 infant recordings were included in the final analysis. OUTCOME MEASURES: AERs were recorded and amplitudes were normalized to the amplitude of the first stimulus. RESULTS: In both fetuses and infants, the amplitudes of AERs were found not to decrease with repeated stimulation. In infants, however, amplitude of syllable 6 (dishabituator) was significantly increased compared to syllable 5 (p=0.026). CONCLUSIONS: Fetuses and infants showed AERs to syllables. Unlike fetuses, infants showed a discriminative neural response to syllables. Habituation was not observed in either fetuses or infants. These findings could be important for the investigation of early cognitive competencies and may help to gain a better understanding of language acquisition during child development.


Assuntos
Estimulação Acústica , Feto/fisiologia , Habituação Psicofisiológica/fisiologia , Desenvolvimento da Linguagem , Magnetoencefalografia , Encéfalo/fisiologia , Cognição/fisiologia , Potenciais Evocados Auditivos , Feminino , Idade Gestacional , Humanos , Lactente , Recém-Nascido , Gravidez
SELEÇÃO DE REFERÊNCIAS
Detalhe da pesquisa