5,295 research outputs found
Bose-Einstein Correlations and Sonoluminescence
Sonoluminescence may be studied in detail by intensity correlations among the
emitted photons. As an example, we discuss an experiment to measure the size of
the light-emitting region by the Hanbury Brown-Twiss effect. We show that
single bubble sonoluminescence is almost ideally suited for study by this
method and that plausible values for the physical parameters are within easy
experimental reach. A sequence of two and higher order photon correlation
experiments is outlined.Comment: Latex File, 8 pages, Postscript file with 2 figs. attache
Gravitational instability and star formation in disk galaxies
We present a general star formation law where star formation rate depends
upon efficiency , timescale of star formation, gas component
of surface mass density and a real exponent . A given exponent
determines which however yields the corresponding star formation
rate. Current nominal Schmidt exponent for our model is .
Based on a gravitational instability parameter and another
dimensionless parameter , where =
pressure, = column density of molecular clouds, we suggest a
general equation for star formation rate which depends upon relative competence
of the two parameters for various physical circumstances. We find that
emerges to be a better parameter for star formation scenario than Toomre
Q-parameter. Star formation rate in the solar neighbourhood is found to be in
good agreement with values inferred from previous studies. Under closed box
approximation model, we obtain a relation between metallicity of gas and the
efficiency of star formation. Our model calculations of metallicity in the
solar neighbourhood agree with earlier estimates. We conclude that metallicity
dispersion for stars of same age may result due to a change in efficiency
through which different sample stars were processed. For no significant change
of metallicity with age, we suggest that all sample stars were born with almost
similar efficiency.Comment: 10 pages, 3 figures, submitted to MNRA
Occurrence and incidence of foot rot disease on fenugreek caused by Fusarium moniliforme in Rohilkhand region of Uttar Pradesh, India
Pathological studies were carried out in Rohilkhand region during the crop season 2013-14 to assess the pathogenic disease incidence of foot rot of fenugreek (Trigonella foenum-graecum Linn.) caused by Fusarium moniliforme. A total of 75 fields were surveyed during the crop period at monthly interval during germination, vegetative, flowering and fruiting stages in five different localities of Rohilkhand region. The foot-rot disease of fenugreek was found in all fields (Bareilly, Baheri, Pilibhit, Budaun and Meerganj) selected for the study. Monthly occurrence of disease incidence of foot rot ranged from 44-58%. Maximum disease incidence was recorded in the month of Oct. (58%) followed by September (57%) and November (56%). January exhibited the lowest incidence (45%) of pathogenic disease. However, foot rot symptoms developed at early stage of plant growth and persisted up to the end of the crop
Insulin-like growth factor 1 signaling in motor neuron and polyglutamine diseases: From molecular pathogenesis to therapeutic perspectives
The pleiotropic peptide insulin-like growth factor 1 (IGF-I) regulates human body homeostasis and cell growth. IGF-I activates two major signaling pathways, namely phosphoinositide-3-kinase (PI3K)/protein kinase B (PKB/Akt) and Ras/extracellular signal-regulated kinase (ERK), which contribute to brain development, metabolism and function as well as to neuronal maintenance and survival. In this review, we discuss the general and tissue-specific effects of the IGF-I pathways. In addition, we present a comprehensive overview examining the role of IGF-I in neurodegenerative diseases, such as spinal and muscular atrophy, amyotrophic lateral sclerosis, and polyglutamine diseases. In each disease, we analyze the disturbances of the IGF-I pathway, the modification of the disease protein by IGF-I signaling, and the therapeutic strategies based on the use of IGF-I developed to date. Lastly, we highlight present and future considerations in the use of IGF-I for the treatment of these disorders
Complexing Behaviour of 2-Thioorotic Acid: Complexes of Co(II), Fe(II), Rh(III), Pd(IV) & Pt(IV)
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