369 research outputs found
Cerebrovascular function in aging and dementia: a systematic review of transcranial Doppler studies
No full textAbstract not availableHannah A.D. Keage, Owen F. Churches, Mark Kohler, Danielle Pomeroy, Rocco Luppino, Michelle L. Bartolo, Scott Elliot
The food and feeding of powan Coregonus lavaretus (L.) (Salmonidae: Coregoninae) in two Scottish lochs
No full textThe present study is mainly a descriptive account of the food and
feeding of the two Scottish powan populations from Loch Lomond and
Loch Eck. Quantitative and qualitative comparisons of powan diet are
made. Seasonal variations of diet are determined for the two
populations and some aspects of the planktivorous feeding of adult
pawan in Loch Lomond are examined. The partitioning of the ingested
energy into somatic and non-somatic growth is considered. Factors
affecting the feeding of the two populations are discussed
Sexual dimorphism in diaphyseal cross-sectional shape in the Medieval Muslim population of Écija, Spain and Anglo-Saxon Great Chesterford, UK
No full textDifferences in adult male and female activity patterns may influence levels of sexual dimorphism in physical dimensions, including the cross-sectional shape of long bone diaphyses. Previous studies of archaeological populations have demonstrated significant differences in diaphyseal shape between males and females. In this study, dimorphism in external diaphyseal shape of upper and lower limb bones (reflected in indices of external diaphyseal diameters), and bilateral asymmetry in these indices, were examined in two medieval populations: Muslim Écija (Spain) and Anglo-Saxon Great Chesterford (UK). Attempts were made to relate observed patterns to documentary and other osteological evidence for differences in male and female activity patterns. While few significant differences in upper limb bone cross-sectional shape were observed in either population, significant differences in shape were found in the lower limb diaphyses at Écija at the femoral midshaft and tibial foramen and midshaft levels, and at the tibial midshaft for Great Chesterford. Comparison with published data suggests that these differences are marked for Écija, and perhaps fairly high for Great Chesterford compared with other populations with an agriculture-based economy. This is consistent with documentary and osteological evidence suggesting marked gender differences in behaviour in medieval Muslim Spain. No significant differences in bilateral asymmetry were found, but the effects of small sample size cannot be ruled out
Human TUBB3 mutations perturb microtubule dynamics, kinesin interactions, and axon guidance
No full textWe report that eight heterozygous missense mutations in TUBB3, encoding the neuron-specific beta-tubulin isotype III, result in a spectrum of human nervous system disorders that we now call the TUBB3 syndromes. Each mutation causes the ocular motility disorder CFEOM3, whereas some also result in intellectual and behavioral impairments, facial paralysis, and/or later-onset axonal sensorimotor polyneuropathy. Neuroimaging reveals a spectrum of abnormalities including hypoplasia of oculomotor nerves and dysgenesis of the corpus callosum, anterior commissure, and corticospinal tracts. A knock-in disease mouse model reveals axon guidance defects without evidence of cortical cell migration abnormalities. We show that the disease-associated mutations can impair tubulin heterodimer formation in vitro, although folded mutant heterodimers can still polymerize into microtubules. Modeling each mutation in yeast tubulin demonstrates that all alter dynamic instability whereas a subset disrupts the interaction of microtubules with kinesin motors. These findings demonstrate that normal TUBB3 is required for axon guidance and maintenance in mammals.Max A. Tischfield, Hagit N. Baris, Chen Wu, Guenther Rudolph, Lionel Van Maldergem, Wei He, Wai-Man Chan, Caroline Andrews, Joseph L. Demer, Richard L. Robertson, David A. Mackey, Jonathan B. Ruddle, Thomas D. Bird, Irene Gottlob, Christina Pieh, Elias I. Traboulsi, Scott L. Pomeroy, David G. Hunter, Janet S. Soul, Anna Newlin, Louise J. Sabol, Edward J. Doherty, Clara E. de Uzca´ tegui, Nicolas de Uzca´ tegui, Mary Louise Z. Collins, Emin C. Sener, Bettina Wabbels, Heide Hellebrand, Thomas Meitinger, Teresa de Berardinis, Adriano Magli, Costantino Schiavi, Marco Pastore-Trossello, Feray Koc, Agnes M. Wong, Alex V. Levin, Michael T. Geraghty, Maria Descartes, Maree Flaherty, Robyn V. Jamieson, H.U. Møller, Ingo Meuthen, David F. Callen, Janet Kerwin, Susan Lindsay, Alfons Meindl, Mohan L. Gupta, Jr., David Pellman, and Elizabeth C. Engl
Growth processes in the two Scottish populations of powan, Coregonus lavaretus (L.) (Eateleosteia, Salmonidae)
No full textThe powan, Coregonus lavaretus (L.) is endemic to only two
British waters, Loch Lomond and Loch Eck, Scotland. This
thesis describes the seasonal and longer term growth
processes of the two populations, concentrating on growth in
length back-calculated from scales, factors affecting
recruitment and mortality, reproductive cycles, and seasonal
deposition and mobilisation of storage products,
particularly lipid. The interrelationships of these cycles
is discussed. The populations differ in their diet and
duration of feeding, and it is shown that most of the inter-population differences in seasonal cycles of growth relate
to these feeding differences. The Loch Eck population is the
more variable. In addition to adult and immature powan, a
third category is identified, termed adolescents. These are
fish which are entering their first reproductive cycle.
Immature and adolescent fish are analysed separately and
compared with the adults. There are some differences in
seasonal cycles between the juveniles and adults, mainly in
relation to the presence or absence of the reproductive
cycle. A preliminary histological study of the ovaries of
adolescent females is carried out. Comparison of historical
data with the results of the present study shows that there
has been little change in the Loch Lomond powan in the past
200 years. Both lochs are coming under increasing human
pressure, and conservational measures urgently need to be
taken if the powan populations are to survive
Estimating demographic parameters for capture-recapture data in the presence of multiple mark types
No full textIn mark-recapture studies, various techniques can be used to uniquely identify individual animals, such as ringing, tagging or photo-identification using natural markings. In some long-term studies more than one type of marking procedure may be implemented during the study period. In these circumstances, ignoring the different mark types can produce biased survival estimates since the assumption that the different mark types are equally catchable (homogeneous capture probability across mark types) may be incorrect.We implement an integrated approach where we simultaneously analyse data obtained using three different marking techniques, assuming that animals can be cross-classified across the different mark types. We discriminate between competing models using the AIC statistic. This technique also allows us to estimate both relative mark-loss probabilities and relative recapture efficiency rates for the different marking methods.We initially perform a simulation study to explore the different biases that can be introduced if we assume a homogeneous recapture probability over mark type, before applying the method to a real dataset. We make use of data obtained from an intensive long-term observational study of UK female grey seals (Halichoerus grypus) at a single breeding colony, where three different methods are used to identify individuals within a single study: branding, tagging and photo-identification based on seal coat pattern or pelage.Peer reviewe
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