52 research outputs found
Plausible Mechanisms for Brain Structural and Size Changes in Human Evolution
Encephalization has many contexts and implications. On one hand, it is concerned with the transformation of eating
habits, social relationships and communication, cognitive skills and the mind. Along with the increase in brain size on
the other hand, encephalization is connected with the creation of more complex brain structures, namely in the cerebral
cortex. It is imperative to inquire into the mechanisms which are linked with brain growth and to find out which of these
mechanisms allow it and determine it. There exist a number of theories for understanding human brain evolution which
originate from neurological sciences. These theories are the concept of radial units, minicolumns, mirror neurons, and
neurocognitive networks. Over the course of evolution, it is evident that a whole range of changes have taken place in regards
to heredity. These changes include new mutations of genes in the microcephalin complex, gene duplications, gene
co-expression, and genomic imprinting. This complex study of the growth and reorganization of the brain and the functioning
of hereditary factors and their external influences creates an opportunity to consider the implications of cultural
evolution and cognitive faculties
Body composition estimation from selected slices:equations computed from a new semi-automatic thresholding method developed on whole-body CT scans
Background Estimating volumes and masses of total body components is important for the study and treatment monitoring of nutrition and nutrition-related disorders, cancer, joint replacement, energy-expenditure and exercise physiology. While several equations have been offered for estimating total body components from MRI slices, no reliable and tested method exists for CT scans. For the first time, body composition data was derived from 41 high-resolution whole-body CT scans. From these data, we defined equations for estimating volumes and masses of total body AT and LT from corresponding tissue areas measured in selected CT scan slices. Methods We present a new semi-automatic approach to defining the density cutoff between adipose tissue (AT) and lean tissue (LT) in such material. An intra-class correlation coefficient (ICC) was used to validate the method. The equations for estimating the whole-body composition volume and mass from areas measured in selected slices were modeled with ordinary least squares (OLS) linear regressions and support vector machine regression (SVMR). Results and Discussion The best predictive equation for total body AT volume was based on the AT area of a single slice located between the 4th and 5th lumbar vertebrae (L4-L5) and produced lower prediction errors (|PE| = 1.86 liters, %PE = 8.77) than previous equations also based on CT scans. The LT area of the mid-thigh provided the lowest prediction errors (|PE| = 2.52 liters, %PE = 7.08) for estimating whole-body LT volume. We also present equations to predict total body AT and LT masses from a slice located at L4-L5 that resulted in reduced error compared with the previously published equations based on CT scans. The multislice SVMR predictor gave the theoretical upper limit for prediction precision of volumes and cross-validated the results
On the diet of Tycho Brahe and his wife: did they consume fish from stagnant pools?
Radiocarbon dating has been performed on cortical femoral tissue samples from Tycho Brahe (1546–1601) and his wife Kirsten Barbara Jørgensdatter (1549–1604). No discernible reservoir effect has been observed in either skeleton. This combined with unusually high δ15N values and seemingly terrestrial δ13C values, makes us suggest that a large fraction of their protein intake came from freshwater fish raised in stagnant pools.[Figure not available: see fulltext.
Was He Murdered or Was He Not?-Part II:Multi-Elemental Analyses of Hair and Bone Samples from Tycho Brahe and Histopathology of His Bones
Variability in the Upper Palaeolithic skulls from Predmostí: comparisons with populations inhabiting Bohemia and Moravia from prehistory to the present
Plausible Mechanisms for Brain Structural and Size Changes in Human Evolution
Encephalization has many contexts and implications. On one hand, it is concerned with the transformation of eating
habits, social relationships and communication, cognitive skills and the mind. Along with the increase in brain size on
the other hand, encephalization is connected with the creation of more complex brain structures, namely in the cerebral
cortex. It is imperative to inquire into the mechanisms which are linked with brain growth and to find out which of these
mechanisms allow it and determine it. There exist a number of theories for understanding human brain evolution which
originate from neurological sciences. These theories are the concept of radial units, minicolumns, mirror neurons, and
neurocognitive networks. Over the course of evolution, it is evident that a whole range of changes have taken place in regards
to heredity. These changes include new mutations of genes in the microcephalin complex, gene duplications, gene
co-expression, and genomic imprinting. This complex study of the growth and reorganization of the brain and the functioning
of hereditary factors and their external influences creates an opportunity to consider the implications of cultural
evolution and cognitive faculties
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