statistical studies on palynology contents of late cretaceous to paleocene age gurpi formation in a surface section in zagros basin,sw iran indicate changes in abundance, species diversity, ratio of spiniferites to cyclonephelium (s/c), palynological marine index(pmi) values and organic facies. these palynological variations clearly reflect fluctuations in relative sea-level and depositionalenv...

Simple meiotic gene conversion tracts produced in wild-type females were compared with those from two meiotic mutants, mei-9 and mei-218. The positions and lengths of conversion tracts were determined by denaturing gradient gels and DNA sequencing. Conversion tracts in wild type averaged 885 base pairs in length, were continuous, and displayed no obvious hot spots of initiation. Some unusual co...

The N-terminal region of human HOXA13 has seven discrete polyalanine tracts. Our previous analysis of these tracts in multiple major vertebrate clades suggested that three are mammal-specific. We now report the N-terminal HOXA13 repetitive tract structures in the monotreme Tachyglossus aculeatus (echidna). Contrary to our expectations, echidna HOXA13 possesses a unique set of polyalanine tracts...

Endocardial and epicardial activation pathways of the canine right atrium. Am. JS Physiol. 220(l) : l-l 1. 197 1 .-Right atria1 epicardial and endocardial activation was explored in Langendorff-perfused canine hearts during sinus rhythm and during stimulation near the coronary sinus and elsewhere in the right atrium. Control experiments demonstrate close correlation to epicardial activation in ...

Human white matter integrity has been related to information processing speed, but it is unknown whether impaired integrity results from localized processes or is a general property shared across white matter tracts. Based on diffusion MRI scans of 132 healthy individuals with a narrow age range around 72 years, the integrity of eight major white matter tracts was quantified using probabilistic...

To explore fundamental principles characterizing chemosensory information processing, we have identified antennal-lobe projection neurons in the heliothine moth, including several neuron types not previously described. Generally, odor information is conveyed from the primary olfactory center of the moth brain, the antennal lobe, to higher brain centers via projection neuron axons passing along ...

Poly(dA.dT) sequences (T-tracts) are abundant genomic DNA elements with unusual properties in vitro and an established role in transcriptional regulation of yeast genes. In vitro T-tracts are rigid, contribute to DNA bending, affect assembly in nucleosomes and generate a characteristic pattern of CPDs (cyclobutane pyrimidine dimers) upon irradiation with UV light (UV photofootprint). In eukaryo...