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Biomedical subjects

P Hari

Publications and source records attributed to P Hari.

26 records · Page 2Linked to original sources
PubMed1995

Methods for combining phenological time series: application to bud burst in birch (Betula pendula) in Central Finland for the period 1896-1955.

We compared four methods for combining separate fragmentary phenological time series into a single long reliable series. The systematic linear effect of differences in observers, genotypes, geography and climate at the observation points produces disturbing variation in the observations and bias in the means of some time points. The three methods based on the adjustment of individual series eliminated the disturbing variation and bias. The methods were compared based on phenological observations of bud burst in birch (Betula pendula Roth). The method based on a linear mixed model of analysis of variance and the maximum likelihood estimation was considered preferable to the other methods.

Journal Article↗
PubMed1993

Suppression of magnetic mu rhythm during parkinsonian tremor.

We recorded spontaneous magnetoencephalographic (MEG) activity and somatosensory-evoked fields (SEFs) with a 24-channel planar SQUIDgradiometer in five patients with hemiparkinsonism. The SEFs of the patients were within normal limits. During tremorless periods, the spontaneous activity over the somatomotor cortex had a frequency peak at approximately 10 Hz in all five patients and another at approximately 20 Hz in three. Tremor dampened the 10-Hz activity in all patients; in three the effect was bilateral. Tremor did not increase MEG activity at the tremor frequency. The suppression of the mu rhythm by the parkinsonian tremor resembled that occurring during voluntary movements in healthy subjects.

Adult↗
PubMed1991

The utilization of old phenological time series of budburst to compare models describing annual cycles of plants.

A phenological time series of the date of budburst of birch (Betula pendula) was constructed using data from the years 1907-1950. Data for the years 1908, 1910-1915 and 1930 are missing. The phenological observations were made at Saarijärvi (62 degrees 42' N, 25 degrees 44' E) in Central Finland. Different models describing the rate of development in the spring were analyzed using temperature data from the city of Jyväskylä about 60 km to the southeast of Saarijärvi. The models based on temperature sum gave more accurate predictions of the date of budburst than the model based on time. Differences between different development rates seemed to be negligible when computing the temperature sum.

Journal Article↗
PubMed1990

Timing of growth cessation in relation to climatic adaptation of northern woody plants.

The efficiency of timing models of cessation of growth of northern woody plants was defined as their ability to allow maximum utilization of the growing season without autumn frost damage. The efficiencies of three timing models were compared with the aid of computer simulations, using long-term meteorological data. A model based on night length was the most efficient, followed by one based on a joint factor of the night length and temperature sum. A model based on temperature sum alone was the least efficient. The reason for these differences in efficiency was the great year-to-year variation in the annual temperature sum accumulation. The results were compared with empirical evidence for each of the models. The relevance of the theoretical approach is discussed, as well as the application of the simulations.

Journal Article↗
PubMedDate not supplied

Pulse corticosteroid therapy with methylprednisolone or dexamethasone.

Intravenous pulse steroid therapy consists of administration of supraphysiological doses of glucocorticoids. It is useful in conditions where rapid immunosuppression and antiinflammatory effect is desired, as in systemic lupus erythematosus, pemphigus, renal transplantation, steroid resistant nephrotic syndrome and crescentic glomerulonephritis. This therapy may be associated with significant adverse reactions including hypertension, arrhythmias, hypokalemia, psychosis and infections. High dose steroid therapy should therefore be used in selected cases and under careful supervision. The drug most widely used for this treatment is methylprednisolone. However, in view of its easy availability and cost, dexamethasone has been often used in India for the above conditions. While there are no controlled studies comparing the two drugs, it appears that the two drugs may be similar in efficacy. Patients requiring high dose intravenous steroid therapy may be treated effectively with either methylprednisolone or dexamethasone.

Anti-Inflammatory Agents↗
PubMedDate not supplied

NMR characterization of hydrocarbon gas in porous media.

Laboratory investigations of nuclear magnetic resonance (NMR) relaxation properties of methane gas in bulk and in porous media are reported. Measurements were performed for methane alone and together with water in glass bead packs and Bentheimer sandstone. Results indicate that surface relaxation effects can be significant and that diffusion effects dominate observed T2 relaxation.

Gases↗