1,030 research outputs found
Dual automorphism-invariant modules
A module is called an automorphism-invariant module if every isomorphism
between two essential submodules of extends to an automorphism of . This
paper introduces the notion of dual of such modules. We call a module to be
a dual automorphism-invariant module if whenever and are small
submodules of , then any epimorphism with
small kernel lifts to an endomorphism of . In this paper we give
various examples of dual automorphism-invariant module and study its
properties. In particular, we study abelian groups and prove that dual
automorphism-invariant abelian groups must be reduced. It is shown that over a
right perfect ring , a lifting right -module is dual
automorphism-invariant if and only if is quasi-projective.Comment: To appear in Journal of Algebr
Rings of Invariant Module Type and Automorphism-Invariant Modules
A module is called automorphism-invariant if it is invariant under any
automorphism of its injective hull. In [Algebras for which every indecomposable
right module is invariant in its injective envelope, Pacific J. Math., vol. 31,
no. 3 (1969), 655-658] Dickson and Fuller had shown that if is a
finite-dimensional algebra over a field with more than two elements
then an indecomposable automorphism-invariant right -module must be
quasi-injective. In this paper we show that this result fails to hold if
is a field with two elements. Dickson and Fuller had further shown
that if is a finite-dimensional algebra over a field with more
than two elements, then is of right invariant module type if and only if
every indecomposable right -module is automorphism-invariant. We extend the
result of Dickson and Fuller to any right artinian ring. A ring is said to
be of right automorphism-invariant type (in short, RAI-type) if every finitely
generated indecomposable right -module is automorphism-invariant. In this
paper we completely characterize an indecomposable right artinian ring of
RAI-type.Comment: To appear in Contemporary Mathematics, Amer. Math. So
जलाशय मात्स्यिकी प्रबंधन में पिंजरों में मछ्ली पालन के महत्व की एक वैज्ञानिक विवेचना
कृपया पूरा लेखा पढ
Some ratio type estimators under measurement errors
This article addresses the problem of estimating the population mean using auxiliary information in the presence of measurement errors
Ichthyofaunal diversity in Bachan Gad and Kakda streams of the Mid-himalayan Ganga river system of Garhwal in relation to stream gradient and distance
The present study was carried out to investigate the comparative seasonal distribution and relative abundance of fish fauna of streams Bachan Gad of river Alaknanda and Kakda Gad of river Mandakini of Mid-himalayan Ganga river System. Total length of the Bachan Gad is 14.5 km from origin to the confluence at main river Alaknanda with an altitudinal variation from 605.94 to 1418.23m (a.s.1), whereas, total length of the Kakda Gad is 15.5 km. from origin to confluence at main river Mandakini with altitudinal variation from 984.50 to 1993.70 m (a.s.1). Total 23 species from Bachan Gad and 20 fish species were identified from Kakda Gad. The differences in the availability of fish-fauna were directly related to the nature of the profile and slope of tributaries; which affects the migration and breeding grounds of the fishes inhabited in the main river Alaknanda and Mandakini of Ganga river system. Variation in the availability of fishes has been recorded from different sites of the stream. In streams and rivers the changes take place along their length is directly related to the eco-physico-chemical nature (water depth, current, substratum etc). All these factors which change along the length of streams are also the factors which control the distribution of the various sections of the biotic fauna and flora
Quantitative osteological study of a bottom feeder hillstream cyprinoid fish Crossocheilus latius latius (Hamilton- Buchanan)
The quantitative osteological study has been conducted on a Hillstream bottom feeder fish Crossocheilus latius latius. C. latius latius is a common hillstream fish of Snowfed Rivers of Alaknanda. The bones have been taken from different sized fishes ranged from 13 to 27 Cm in length and 39 to 132 gm in weight. The correlation is applied between Body Weight and the Weight of different disarticulated bones of C. latius latius. The correlation (r) is highly significant among the different parameter of body in relation to osteology which ranged from r = 0.952; P<0.1 to r = 0.999; P< 0.1
Nutrient Management for Higher Productivity of Swarna Sub1 Under Flash Floods Areas
Two field experiments were conducted at Regional Agricultural Research Station, Tarahara, Nepal during 2012 and 2013 to determine the effect of agronomic management on growth and yield of Swarna Sub1 under flash floods. The first experiment was laid out in a split plot design with three replications; and four different nutrient combinations at nursery as main plots and three age groups of rice seedlings as sub plots. The second experiment was laid out in a randomized complete block design and replicated thrice; with three post flood nutrient doses at six and 12 days after de-submergence (dad). The experiments were complete submerged at 10 days after transplanting for 12 days. The survival percentage, at 21 dad, was significantly higher in plots planted with 35 (90.25%) and 40 (91.58%) days-old seedlings compared to 30 days-old seedlings (81.75%). Plots with 35 days-old seedlings produced 5.15 t ha-1 with advantage of 18.83% over 30 days-old seedlings. Plots with 100-50-50 kg N-P2O5-K2O/ha at nursery recorded the highest grain filling of 79.41% and grain yield of 5.068 t/ha with more benefit. Post flood application of 20-20 N-K20kg/ha at 6 dad resulted in higher plant survival and taller plants, leading to significantly higher grain yield of 5.183 t/ha and straw yield of 5.315 t/ha. Hence, 35-40 days old seedlings raised with 100-50-50 kg N-P2O5-K2O /ha in nursery and the additional application of20-20 kg N-K2O /ha at 6 dad improved plant survival and enhanced yield of Swarna Sub1 under flash flood conditions. The practice has prospects of saving crop loss with getting rice yield above national average yield leading to enhanced food security in the flood prone areas of Nepal
Temperature dependence of 1/f noise in Gallium Nitride epitaxial layer
1/f noise investigation was performed on n-GaN epitaxial layer grown on sapphire. The variation of spectral power density of voltage fluctuations density was observed as a function of frequency (100-50 Hz) and it showed the 1/f spectra. This type of
behavior was attributed to the presence of traps. The variation in spectral power density of voltage fluctuations with temperature was also observed with in the temperature range 80 K and 300 K and it was found to be slightly increasing with
temperature. It was attributed to the trapping-detrapping process of charge carriers by the defects. Four probe configuration was used for noise measurement and contacts
were made with indium. To check the stability and ohmic behavior of contacts, I-V measurements were performed with in the temperature range 80-325 K.
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