Mapping genetic influences on brain fiber architecture with high angular resolution diffusion imaging (HARDI)

We report the first 3D maps of genetic effects on brain fiber complexity. We analyzed HARDI brain imaging data from 90 young adult twins using an information-theoretic measure, the Jensen-Shannon divergence (JSD), to gauge the regional complexity of the white matter fiber orientation distribution functions (ODF). HARDI data were fluidly registered using Karcher means and ODF square-roots for interpol ation; each subject's JSD map was computed from the spatial coherence of the ODFs in each voxel's neighborhood. We evaluated the genetic influences on generalized fiber anisotropy (GFA) and complexity (JSD) using structural equation models (SEM). At each voxel, genetic and environmental components of data variation were estimated, and their goodness of fit tested by permutation. Color-coded maps revealed that the optimal models varied for different brain regions. Fiber complexity was predominantly under genetic control, and was higher in more highly anisotropic regions. These methods show promise for discovering factors affecting fiber connectivity in the brain.

Quantitative genetic modeling of lateral ventricular shape and volume using multi-atlas fluid image alignment in twins

Despite substantial progress in measuring the 3D profile of anatomical variations in the human brain, their genetic and environmental causes remain enigmatic. We developed an automated system to identify and map genetic and environmental effects on brain structure in large brain MRI databases . We applied our multi-template segmentation approach ("Multi-Atlas Fluid Image Alignment") to fluidly propagate hand-labeled parameterized surface meshes into 116 scans of twins (60 identical, 56 fraternal), labeling the lateral ventricles. Mesh surfaces were averaged within subjects to minimize segmentation error. We fitted quantitative genetic models at each of 30,000 surface points to measure the proportion of shape variance attributable to (1) genetic differences among subjects, (2) environmental influences unique to each individual, and (3) shared environmental effects. Surface-based statistical maps revealed 3D heritability patterns, and their significance, with and without adjustments for global brain scale. These maps visualized detailed profiles of environmental versus genetic influences on the brain, extending genetic models to spatially detailed, automatically computed, 3D maps.

Comparison of fractional and geodesic anisotropy in diffusion tensor images of 90 monozygotic and dizygotic twins

We used diffusion tensor magnetic resonance imaging (DTI) to reveal the extent of genetic effects on brain fiber microstructure, based on tensor-derived measures, in 22 pairs of monozygotic (MZ) twins and 23 pairs of dizygotic (DZ) twins (90 scans). After Log-Euclidean denoising to remove rank-deficient tensors, DTI volumes were fluidly registered by high-dimensional mapping of co-registered MP-RAGE scans to a geometrically-centered mean neuroanatomical template. After tensor reorientation using the strain of the 3D fluid transformation, we computed two widely used scalar measures of fiber integrity: fractional anisotropy (FA), and geodesic anisotropy (GA), which measures the geodesic distance between tensors in the symmetric positive-definite tensor manifold. Spatial maps of intraclass correlations (r) between MZ and DZ twins were compared to compute maps of Falconer's heritability statistics, i.e. the proportion of population variance explainable by genetic differences among individuals. Cumulative distribution plots (CDF) of effect sizes showed that the manifold measure, GA, comparably the Euclidean measure, FA, in detecting genetic correlations. While maps were relatively noisy, the CDFs showed promise for detecting genetic influences on brain fiber integrity as the current sample expands.

Constructing abstract maps from spatial descriptions for goal-directed exploration

This paper describes ongoing work on a system using spatial descriptions to construct abstract maps that can be used for goal-directed exploration in an unfamiliar office environment. Abstract maps contain membership, connectivity, and spatial layout information extracted from symbolic spatial information. In goal-directed exploration, the robot would then link this information with observed symbolic information and its grounded world representation. We demonstrate the ability of the system to extract and represent membership, connectivity, and spatial layout information from spatial descriptions of an office environment. In the planned study, the robot will navigate to the goal location using the abstract map to inform the best direction to explore in.

Validation of processing maps for 304L stainless steel using hot forging, rolling and extrusion

The development of a microstructure in 304L stainless steel during industrial hot-forming operations, including press forging (mean strain rate of 0.15 s(-1)), rolling/extrusion (2-5 s(-1)), and hammer forging (100 s(-1)) at different temperatures in the range 600-1200 degrees C, was studied with a view to validating the predictions of the processing map. The results have shown that excellent correlation exists between the regimes exhibited by the map and the product microstructures. 304L stainless steel exhibits instability bands when hammer forged at temperatures below 1100 degrees C, rolled/extruded below 1000 degrees C, or press forged below 800 degrees C. All of these conditions must be avoided in mechanical processing of the material. On the other hand, ideally, the material may be rolled, extruded, or press forged at 1200 degrees C to obtain a defect-free microstructure.

« Le roman est agréablement traduit » : Étude comparative sur la visibilité des traductions et des traducteurs en Finlande et en France à travers des critiques des livres

Pro gradu -työssä tutkitaan ja vertaillaan käännöskirjallisuuden arvosteluja Ranskassa ja Suomessa. Empiirinen aineisto koostuu kaikista Helsingin Sanomien ja Le Monden vuonna 2003 julkaisemista arvosteluista. Lehdissä oli yhteensä 2691 arvosteltua kirjaa, joista 845 oli käännöksiä. Päätavoite on ollut selvittää näiden valtasanomalehtien kritiikkejä tutkimalla, kummassa maassa kääntäjän ja käännöksen asema on näkyvämpi ja minkälaisia julkaistut käännöskritiikit ovat. Lisäksi tavoitteena on ollut tutkia, kumpi lehdistä on avoimempi vieraskielisiä kirjoja ja käännöksiä kohtaan. Kirja-arvostelujen lähemmälle tutkimiselle luodaan pohjaa perehtymällä kääntäjän ja käännöksen näkyvyyteen liittyviin seikkoihin. Tässä käytetään hyväksi Koskisen (2000) tutkimusta. Tutkimuksessa tarkastellaan myös, millainen on hyvä käännös eri kääntäjien ja tutkijoiden mielestä, sekä muita saman aihepiirin tutkimuksia ja aiheesta vallalla ollutta keskustelua. Lisäksi selvitetään, miksi laadukkaat käännösarvostelut ovat harvinaisia ja mistä tämä johtuu. Analyysivaiheen kvantitatiivisessa osassa perehdytään käännösten määrälliseen osuuteen sekä aineistossa että Ranskan ja Suomen kokonaisjulkaisumäärissä. Aineiston käännösarvostelut luokitellaan niiden sisällön mukaan. Tässä on käytetty soveltuvin osin Gullinin (1998) kehittelemää mallia. Käännösarvostelujen sisältöanalyysissa kiinnitetään huomiota niiden käännöstä ja kääntäjää koskeviin kommentteihin. Arvostelujen laadun ja kriitikkojen käyttämien arvosteluperusteiden pohdinta nojautuu aiheesta aikaisemmin tehtyihin teoreettisiin sekä empiirisiin tutkimuksiin. Pro gradu -työ sisältää myös erillisen katsauksen käännettyjen lastenkirjojen arvosteluihin sekä arvostelujen ulkopuolisiin kääntäjiin ja kääntämiseen liittyviin artikkeleihin. Koko tutkimuksen ajan lähestymistapa on vertaileva Le Monden ja Helsingin Sanomien välillä. Tutkimuksesta selviää, että Le Monde julkaisee huomattavasti enemmän kirja-arvosteluja. Molemmat lehdet sisältävät kuitenkin suhteellisesti yhtä paljon arvosteluja käännöskirjoista. Helsingin Sanomissa on enemmän vieraskielisten teosten arvosteluja, ja käännösten ja kääntäjän asema on huomattavasti näkyvämpi lehden kritiikeissä. Suurin osa Le Monden käännösarvosteluista sisältää vain kääntäjän nimen bibliografisissa tiedoissa. Helsingin Sanomissa vain alle puolet käännöskirjoista on arvosteltu tällä tavoin. Myös kritiikit, joissa kääntäjän nimeä ei mainita ollenkaan, ovat yleisempiä ranskalaislehdessä. Suhteellisen pieni osa käännösarvosteluista arvioi käännöksen laatua. Näille arvioille on ominaista perustelujen ja analyysin puuttuminen ja ne ovat usein lyhyitä. Arviot ovat sävyltään enimmäkseen positiivisia tai neutraaleja. Hyvin yleistä on myös se, että kriitikko sekoittaa kaksi eri asiaa: kääntäjän ja kirjailijan tyylin. Yleisin kriitikkojen käyttämä arviointikriteeri on tutkia käännöksen ja kohdekielen tai käännöksen ja lähtötekstin suhdetta. Monesti arviointikriteeri jää täysin epäselväksi. Helsingin Sanomien kritiikeissä kääntäjiin viitataan huomattavasti useammin myös itse arvostelutekstissä. Lehti tuo näkyvästi esille kääntäjiä muissakin kuin kirja-arvosteluartikkeleissaan. Sen sijaan Le Mondessa ei ole pelkästään kääntäjiä käsitteleviä tekstejä.

Construction of microsatellite linkage maps for Corymbia

The genus Corymbia is closely related to the genus Eucalyptus, and like Eucalyptus contains tree species that are important for sub-tropical forestry. Corymbia's close relationship with Eucalyptus suggests genetic studies in Corymbia should benefit from transfer of genetic information from its more intensively studied relatives. Here we report a genetic map for Corymbia spp. based on microsatellite markers identified de novo in Corymbia sp or transferred from Eucalyptus. A framework consensus map was generated from an outbred F 2 population (n = 90) created by crossing two unrelated Corymbia torelliana x C. citriodora subsp. variegata F1 trees. The map had a total length of 367 cM (Kosambi) and was composed of 46 microsatellite markers distributed across 13 linkage groups (LOD 3). A high proportion of Eucalyptus microsatellites (90%) transferred to Corymbia. Comparative analysis between the Corymbia map and a published Eucalyptus map identified eight homeologous linkage groups in Corymbia with 13 markers mapping on one or both maps. Further comparative analysis was limited by low power to detect linkage due to low genome coverage in Corymbia, however, there was no convincing evidence for chromosomal structural differences because instances of non-synteny were associated with large distances on the Eucalyptus map. Segregation distortion was primarily restricted to a single linkage group and due to a deficit of hybrid genotypes, suggesting that hybrid inviability was one factor shaping the genetic composition of the F2 population in this inter-subgeneric hybrid. The conservation of microsatellite loci and synteny between Corymbia and Eucalyptus suggests there will be substantial value in exchanging information between the two groups.

How accurate are the marker orders in crop linkage maps generated from large marker datasets?

Marker ordering during linkage map construction is a critical component of QTL mapping research. In recent years, high-throughput genotyping methods have become widely used, and these methods may generate hundreds of markers for a single mapping population. This poses problems for linkage analysis software because the number of possible marker orders increases exponentially as the number of markers increases. In this paper, we tested the accuracy of linkage analyses on simulated recombinant inbred line data using the commonly used Map Manager QTX (Manly et al. 2001: Mammalian Genome 12, 930-932) software and RECORD (Van Os et al. 2005: Theoretical and Applied Genetics 112, 30-40). Accuracy was measured by calculating two scores: % correct marker positions, and a novel, weighted rank-based score derived from the sum of absolute values of true minus observed marker ranks divided by the total number of markers. The accuracy of maps generated using Map Manager QTX was considerably lower than those generated using RECORD. Differences in linkage maps were often observed when marker ordering was performed several times using the identical dataset. In order to test the effect of reducing marker numbers on the stability of marker order, we pruned marker datasets focusing on regions consisting of tightly linked clusters of markers, which included redundant markers. Marker pruning improved the accuracy and stability of linkage maps because a single unambiguous marker order was produced that was consistent across replications of analysis. Marker pruning was also applied to a real barley mapping population and QTL analysis was performed using different map versions produced by the different programs. While some QTLs were identified with both map versions, there were large differences in QTL mapping results. Differences included maximum LOD and R-2 values at QTL peaks and map positions, thus highlighting the importance of marker order for QTL mapping

A consensus genetic map of sorghum that integrates multiple component maps and high-throughput Diversity Array Technology (DArT) markers

Background: Sorghum genome mapping based on DNA markers began in the early 1990s and numerous genetic linkage maps of sorghum have been published in the last decade, based initially on RFLP markers with more recent maps including AFLPs and SSRs and very recently, Diversity Array Technology (DArT) markers. It is essential to integrate the rapidly growing body of genetic linkage data produced through DArT with the multiple genetic linkage maps for sorghum generated through other marker technologies. Here, we report on the colinearity of six independent sorghum component maps and on the integration of these component maps into a single reference resource that contains commonly utilized SSRs, AFLPs, and high-throughput DArT markers. Results: The six component maps were constructed using the MultiPoint software. The lengths of the resulting maps varied between 910 and 1528 cM. The order of the 498 markers that segregated in more than one population was highly consistent between the six individual mapping data sets. The framework consensus map was constructed using a "Neighbours" approach and contained 251 integrated bridge markers on the 10 sorghum chromosomes spanning 1355.4 cM with an average density of one marker every 5.4 cM, and were used for the projection of the remaining markers. In total, the sorghum consensus map consisted of a total of 1997 markers mapped to 2029 unique loci ( 1190 DArT loci and 839 other loci) spanning 1603.5 cM and with an average marker density of 1 marker/0.79 cM. In addition, 35 multicopy markers were identified. On average, each chromosome on the consensus map contained 203 markers of which 58.6% were DArT markers. Non-random patterns of DNA marker distribution were observed, with some clear marker-dense regions and some marker-rare regions. Conclusion: The final consensus map has allowed us to map a larger number of markers than possible in any individual map, to obtain a more complete coverage of the sorghum genome and to fill a number of gaps on individual maps. In addition to overall general consistency of marker order across individual component maps, good agreement in overall distances between common marker pairs across the component maps used in this study was determined, using a difference ratio calculation. The obtained consensus map can be used as a reference resource for genetic studies in different genetic backgrounds, in addition to providing a framework for transferring genetic information between different marker technologies and for integrating DArT markers with other genomic resources. DArT markers represent an affordable, high throughput marker system with great utility in molecular breeding programs, especially in crops such as sorghum where SNP arrays are not publicly available.

Pre-maps : An Educational Programme for Reading Tactile Maps

It is demanding for children with visual impairment to become aware of the world beyond their immediate experience. They need to learn to control spatial experiences as a whole and understand the relationships between objects, surfaces and themselves. Tactile maps can be an excellent source of information for depicting space and environment. By means of tactile maps children can develop their spatial understanding more efficiently than through direct travel experiences supplemented with verbal explanations. Tactile maps can help children when they are learning to understand environmental, spatial, and directional concepts. The ability to read tactile maps is not self-evident; it is a skill, which must be learned. The main research question was: can children who are visually impaired learn to read tactile maps at the preschool age if they receive structural teaching? The purpose of this study was to develop an educational program for preschool children with visual impairment, the aim of which was to teach them to read tactile maps in order to strengthen their orientation skills and to encourage them to explore the world beyond their immediate experience. The study is a multiple case study describing the development of the map program consisting of eight learning tasks. The program was developed with one preschooler who was blind, and subsequently the program was implemented with three other children. Two of the children were blind from birth, one child had lost her vision at the age of two, and one child had low vision. The program was implemented in a normal preschool. Another objective of the pre-map program was to teach the preschooler with visual impairment to understand the concept of a map. The teaching tools were simple, map-like representations called pre-maps. Before a child with visual impairment can read a comprehensive tactile map, it is important to learn to understand map symbols, and how a three-dimensional model changes to a two-dimensional tactile map. All teaching sessions were videotaped; the results are based on the analysis of the videotapes. Two of the children completed the program successfully, and learned to read a tactile map. The two other children felt happy during the sessions, but it was problematic for them to engage fully in the instruction. One of the two eventually completed the program, while the other developed predominantly emerging skills. The results of the children's performances and the positive feedback from the teachers, assistants and the parents proved that this pre-map program is appropriate teaching material for preschool children who are visually impaired. The program does not demand high-level expertise; also parents, preschool teachers, and school assistants can carry out the program.

Outdoor portrait of Ellen Bernkopf nee Catzenstein with her husband Hans Bernkopf; Paris, France. Portraits Couples

Digital Image

Brother of Lola Gruenthal in Nice, France Portraits Men

Brother of Lola Gruenthal

Albert Einstein at blackboard; College de France, Paris France Portraits Men

Digital Image

Leopold Landsberger with other unidentified soldiers standing inside and around a hot air balloon at Verdun, France.

Digital Image