Detailed flow patterns in the nasal cavity.

The human nasal cavity filters and conditions inspired air while providing olfactory function. Detailed experimental study of nasal airflow patterns has been limited because of the complex geometry of the nasal cavity. In this work, particle image velocimetry was used to determine two-dimensional instantaneous velocity vector fields in parallel planes throughout a model of the nasal cavity that was subjected to a nonoscillatory flow rate of 125 ml/s. The model, which was fabricated from 26 computed tomography scans by using rapid prototyping techniques, is a scaled replica of a human right nasal cavity. The resulting vector plots show that the flow is laminar and regions of highest velocity are in the nasal valve and in the inferior airway. The relatively low flow in the olfactory region appears to protect the olfactory bulb from particulate pollutants. Low flows were also observed in the nasal meatuses, whose primary function has been the subject of debate. Comparison of sequentially recorded data suggests a steady flow.     

Divergence time estimates of mammals from molecular clocks and fossils: Relevance of new fossil finds from India

This paper presents a brief review of recent advances in the classification of mammals at higher levels using fossils and molecular clocks. It also discusses latest fossil discoveries from the Cretaceous — Eocene (66–55 m.y.) rocks of India and their relevance to our current understanding of placental mammal origins and diversifications.     

Evaluation of early generations for iron chlorosis in relation to productivity in groundnut (Arachis hypogaea L.)

Five popular but iron-inefficient cultivars were crossed with three efficient genotypes and both parents and F₁s were evaluated for iron-efficiency in potted calcareous and noncalcareous soil. The iron-efficient genotypes were dark green or green in both noncalcareous and calcareous soils whereas inefficient types were light green to yellow in calcareous soil. The chlorophyll and active iron (Fe²⁺) concentration of leaves was less in iron-efficient genotypes compared to efficient types in calcareous soil and reduction of both the parameters from noncalcareous to calcareous soil was considerably high in iron-inefficient lines. There was significant correlation between visual scores, chlorophyll and active iron content. There were no differences among F₁s for iron chlorosis and they were all iron-inefficient. The frequency of iron-inefficient plants was higher than the efficient plants in all F₂ populations. But most of the productive plants came from iron-efficient segregants indicating strong association between iron-efficiency and productivity. Based on the results selection for iron-efficiency in early generations and extensive evaluation for productivity in advanced generations is suggested for developing varieties for cultivation in calcareous soils.     

Localization of neuropeptide Y-like immunoreactivity in the cat hypothalamus

The distribution pattern of neuropeptide Y-like immunoreactivity (NPY-Li) in cat hypothalamus was studied using avidin-biotin modification of immunocytochemical method. This study showed cell bodies containing NPY-Li in the periventricular and the infundibular nuclei and also a moderate number of neurons with NPY-Li in the ventromedial nucleus, an observation not reported in earlier studies. Fibers with NPY-Li were noted throughout the hypothalamus, but most prominently within the periventricular regions. The location of NPY cells within the hypothalamus suggests the possibility of an interaction with dopaminergic and other proopiomelanocortinergic neurons.