1,720,967 research outputs found
Prenatal maternal health and child brain structure: Implications for non-verbal ability and optimizing subcortical segmentation
Get PDFBrain development starts in utero, and the fetal brain can already be affected by the environment, including chemical exposures and maternal health characteristics. These factors range from exposures to large quantities of teratogens (such as alcohol) to variations in the behaviors and characteristics of healthy individuals (such as age, diet, and subclinical levels of depressive and anxiety symptoms), which can nonetheless have long-lasting adverse effects.
In this thesis, we reviewed the literature on the effects of prenatal exposures on human neurodevelopment, as well as cognitive, behavioral, and health outcomes. In Study I we found that prenatal exposures are often reported poorly in infant neuroimaging studies and gave recommendations for reporting in future studies.
In Study II, we examined which early life factors predicted cortical structure in 5-year-olds. The results from Study II were utilized to make an informed decision regarding confounders in future studies in the 5-year-old neuroimaging sample of the FinnBrain Birth Cohort study. In Study III, we explored the cortical structural correlates of non-verbal ability in 5-year-olds. The findings were generally in line with prior results from adult and adolescent studies, with the important addition of a positive association between gray matter volume and surface area in the right medial occipital region and non-verbal ability as well as visual abstract reasoning ability.
Finally, in Study IV, we compared the results from two common segmentation tools, FSL-FIRST and FreeSurfer, against manual segmentation in the hippocampus and subcortical structures. Overall, the agreement with manual segmentation was good, although results were suboptimal for the hippocampus, amygdala, and nucleus accumbens, and careful visual quality control is still recommended.
This thesis summarized different perinatal factors affecting the developing brain, and ensured the high quality of our neuroimaging data. This foundational work, together with the multidisciplinary, longitudinal data collection in the FinnBrain Birth Cohort study, can be used to discover how environmental factors affect brain development.Äidin raskausajan terveys ja lapsen aivojen rakenne: yhteydet ei-kielellisiin taitoihin ja subkortikaalisen segmentaation optimointi
Aivojen kehitys alkaa kohdussa ja jatkuu läpi elämän. Jo sikiöaikana aivot ovat alttiina ympäristön vaikutuksille, ml. kemialliset altisteet sekä äidin terveyteen liittyvät tekijät. Nämä altisteet vaihtelevat suurista annoksista teratogeeneille (esim. alkoholille) eroihin terveiden yksilöiden ominaisuuksissa ja toiminnassa (esim. ikä, ruokavalio sekä vähäiset masennus- ja ahdistusoireet ilman mielenterveyshäiriön diagnoosia), joilla voi kuitenkin olla kauaskantoisia seuraamuksia.
Tässä väitöskirjassa teemme katsauksen raskaudenaikaisten altisteiden vaikutuksista yksilön kehitykseen sekä siihen liittyviin muutoksiin aivoissa. Tutkimuksessa I toteamme, että raskaudenaikaiset altisteet kuvataan usein puutteellisesti vauvojen aivokuvantamista koskevissa tutkimuksissa ja annamme suosituksia raportoinnista.
Tutkimuksessa II tutkimme varhaisten altisteiden yhteyksiä 5-vuotiaiden aivojen rakenteeseen. Tämän tutkimuksen tulokset ohjasivat kontrolloitavien muuttujien valintaa. Tutkimuksessa III tutkimme aivokuoren rakenteen yhteyksiä ei-kielelliseen kognitiiviseen kyvykkyyteen 5-vuotiailla. Tulokset olivat pitkälti linjassa aiempien, vanhemmilla osallistujilla tehtyjen tutkimusten kanssa. Uutena tuloksena löysimme yhteyden oikean takaraivolohkon mediaalisen osan tilavuuden ja pinta-alan olevan yhteydessä ei-kielelliseen kyvykkyyteen sekä erityisesti näönvaraiseen päättelyyn.
Tutkimuksessa IV vertailimme kahta yleistä segmentointityökalua (FreeSurfer ja FSL-FIRST) käsin tehtyyn segmentaatioon hippokampuksessa ja aivokuoren alaisissa tumakkeissa. Tulokset vaihtelivat paljon rakenteesta riippuen. Huolellista laadunvarmistusta aivoalueiden koon määrityksen yhteydessä suositellaan vahvasti.
Tämä väitöskirja antaa kokonaisvaltaisen ymmärryksen aivoihin vaikuttavista varhaisen elämän altisteista. Yhdessä korkealaatuisen aivokuvantamisdatamme sekä muun FinnBrain-syntymäkohortissa kerättävän aineiston kanssa tätä tietoa voidaan hyödyntää useissa tulevissa aivojen kehitystä selvittävissä tutkimuksissa.ei tietoa saavutettavuudest
Prenatal exposures and infant brain: Review of magnetic resonance imaging studies and a population description analysis
No full textBrain development is most rapid during the fetal period and the first years of life. This
process can be affected by many in utero factors, such as chemical exposures and
maternal health characteristics. The goal of this review is twofold: to review the most
recent findings on the effects of these prenatal factors on the developing brain and to
qualitatively assess how those factors were generally reported in studies on infants up
to 2 years of age. To capture the latest findings in the field, we searched articles from
PubMed 2012 onward with search terms referring to magnetic resonance imaging (MRI),
brain development, and infancy. We identified 19 MRI studies focusing on the effects of
prenatal environment and summarized them to highlight the recent advances in the
field. We assessed population descriptions in a representative sample of 67 studies and
conclude that prenatal factors that have been shown to affect brain metrics are not
generally reported comprehensively. Based on our findings, we propose some
improvements for population descriptions to account for plausible confounders and in
time enable reliable meta‐analyses to be performed. This could help the pediatric
neuroimaging field move toward more reliable identification of biomarkers for
developmental outcomes and to better decipher the nuances of normal and abnormal
brain development
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
- …
