564 research outputs found
Comparative Economics of Maize Grain and Seed Production in Okhaldhunga District, Nepal
Maize cultivation is the one the major farm activities among Nepalese farmers. Basically, in the rural hills of Nepal like Okhaldhunga, it dominates any other crop production. The study was conducted for comparative assessment of economics, marketing and identification of major problems of maize seed and grain production in the hilly eastern district, Okhaldhunga during June of 2017. The data were obtained through the interview of 66 producers (33 each of maize grain and seed producers) with a pre-tested semi-structured questionnaire. Descriptive statistics and parametric tests (-test, t-test) were applied. Both the grain and the seed producers were similar in terms of socio-demographic characteristics, marketing accessibilities but the seed producers were significantly benefited from the training, the extension services, credit facilities despite having 0.14 ha lesser landholding than grain producers. The inputs (manures, fertilizers and the seed) contributed 48% and 50% of the total cost incurred for grain and seed production respectively and the pre-sowing and sowing activities contributed more than 77% of cost in both cases. Despite higher cost for seed production (NRs. 24,969 more than grain production), the benefit-cost ratio of seed production was found higher (1.31) than grain production (1.05). Only 24% of the total harvest was processed and marketed as seed and using optimum quantity (66% middle portion of the cob) for seed production could further increase the income by 23.35%, the improved B:C ratio being 1.51 . The major production problems were scarce farm labor followed by lack of infrastructures while low seasonal price followed by low volume of production ranked the first and second most important marketing related problems
Diverse Spatial, Temporal, and Sexual Expression of Recently Duplicated Androgen-Binding Protein Genes in \u3ci\u3eMus musculus\u3c/i\u3e
Background
The genes for salivary androgen-binding protein (ABP) subunits have been evolving rapidly in ancestors of the house mouse Mus musculus, as evidenced both by recent and extensive gene duplication and by high ratios of nonsynonymous to synonymous nucleotide substitution rates. This makes ABP an appropriate model system with which to investigate how recent adaptive evolution of paralogous genes results in functional innovation (neofunctionalization). Results
It was our goal to find evidence for the expression of as many of the Abp paralogues in the mouse genome as possible. We observed expression of six Abpa paralogues and five Abpbg paralogues in ten glands and other organs located predominantly in the head and neck (olfactory lobe of the brain, three salivary glands, lacrimal gland, Harderian gland, vomeronasal organ, and major olfactory epithelium). These Abp paralogues differed dramatically in their specific expression in these different glands and in their sexual dimorphism of expression. We also studied the appearance of expression in both late-stage embryos and postnatal animals prior to puberty and found significantly different timing of the onset of expression among the various paralogues. Conclusion
The multiple changes in the spatial expression profile of these genes resulting in various combinations of expression in glands and other organs in the head and face of the mouse strongly suggest that neofunctionalization of these genes, driven by adaptive evolution, has occurred following duplication. The extensive diversification in expression of this family of proteins provides two lines of evidence for a pheromonal role for ABP: 1) different patterns of Abpa/Abpbg expression in different glands; and 2) sexual dimorphism in the expression of the paralogues in a subset of those glands. These expression patterns differ dramatically among various glands that are located almost exclusively in the head and neck, where the sensory organs are located. Since mice are nocturnal, it is expected that they will make extensive use of olfactory as opposed to visual cues. The glands expressing Abp paralogues produce secretions (lacrimal and salivary) or detect odors (MOE and VNO) and thus it appears highly likely that ABP proteins play a role in olfactory communication
Drastic suppression of CDW (charge density wave) by Pd addition in TiSe2
TiSe2 is a known Topological semimetal (TSM) having both the semi-metallic
and topological characters simultaneously and the Charge density wave (CDW) at
below 200K. In the current short article, we study the impact of Pd addition on
the CDW character of TiSe2 and the possible induction of superconductivity at
low temperatures. Bulk samples of TiSe2 and Pd0.1TiSe2 are synthesized by
solid-state reaction route, which is further characterized by powder X-ray
diffraction (PXRD) and field emission scanning electron microscopy (FESEM),
respectively, for their structural and micro-structural details. The
vibrational modes of both samples are being analyzed by Raman spectroscopy,
showing the occurrence of both A1g and Eg modes. CDW of pure TiSe2 seen at
around 200K in electrical transport measurements, in terms of sharp
semi-metallic to metallic transition peak with hysteresis in cooling/warming
cycles is not seen in Pd0.1TiSe2, and rather a near metallic transport is seen
down to 2K. Although superconductivity is not seen down to 2K, the CDW
transition is seemingly completely suppressed in Pd0.1TiSe2. Pd addition in
TiSe2 suppresses CDW drastically. Trials are underway to induce
superconductivity in Pd-added TiSe2. Density functional theory (DFT)
calculations show primary evidence of suppression of CDW by adding Pd in TiSe2
due to an increase in the density of states.Comment: 11 Pages Text + Figs: Accepted J. Sup. Novel Ma
Congenic Strain Analysis Reveals Genes That Are Rapidly Evolving Components of a Prezygotic Isolation Mechanism Mediating Incipient Reinforcement
Two decades ago, we developed a congenic strain of Mus musculus, called b-congenic, by replacing the androgen-binding protein Abpa27a allele in the C3H/HeJ genome with the Abpa27b allele from DBA/2J. We and other researchers used this b-congenic strain and its C3H counterpart, the a-congenic strain, to test the hypothesis that, given the choice between signals from two strains with different a27 alleles on the same genetic background, test subjects would prefer the homosubspecific one. It was our purpose in undertaking this study to characterize the segment transferred from DBA to the C3H background in producing the b-congenic strain on which a role for ABPA27 in behavior has been predicated. We determined the size of the chromosome 7 segment transferred from DBA and the genes it contains that might influence preference. We found that the “functional" DBA segment is about 1% the size of the mouse haploid genome and contains at least 29 genes expressed in salivary glands, however, only three of these encode proteins identified in the mouse salivary proteome. At least two of the three genes Abpa27, Abpbg26 and Abpbg27 encoding the subunits of androgen-binding protein ABP dimers evolved under positive selection and the third one may have also. In the sense that they are subunits of the same two functional entities, the ABP dimers, we propose that their evolutionary histories might not be independent of each other
Diverse spatial, temporal, and sexual expression of recently duplicated androgen-binding protein genes in Mus musculus
BACKGROUND: The genes for salivary androgen-binding protein (ABP) subunits have been evolving rapidly in ancestors of the house mouse Mus musculus, as evidenced both by recent and extensive gene duplication and by high ratios of nonsynonymous to synonymous nucleotide substitution rates. This makes ABP an appropriate model system with which to investigate how recent adaptive evolution of paralogous genes results in functional innovation (neofunctionalization). RESULTS: It was our goal to find evidence for the expression of as many of the Abp paralogues in the mouse genome as possible. We observed expression of six Abpa paralogues and five Abpbg paralogues in ten glands and other organs located predominantly in the head and neck (olfactory lobe of the brain, three salivary glands, lacrimal gland, Harderian gland, vomeronasal organ, and major olfactory epithelium). These Abp paralogues differed dramatically in their specific expression in these different glands and in their sexual dimorphism of expression. We also studied the appearance of expression in both late-stage embryos and postnatal animals prior to puberty and found significantly different timing of the onset of expression among the various paralogues. CONCLUSION: The multiple changes in the spatial expression profile of these genes resulting in various combinations of expression in glands and other organs in the head and face of the mouse strongly suggest that neofunctionalization of these genes, driven by adaptive evolution, has occurred following duplication. The extensive diversification in expression of this family of proteins provides two lines of evidence for a pheromonal role for ABP: 1) different patterns of Abpa/Abpbg expression in different glands; and 2) sexual dimorphism in the expression of the paralogues in a subset of those glands. These expression patterns differ dramatically among various glands that are located almost exclusively in the head and neck, where the sensory organs are located. Since mice are nocturnal, it is expected that they will make extensive use of olfactory as opposed to visual cues. The glands expressing Abp paralogues produce secretions (lacrimal and salivary) or detect odors (MOE and VNO) and thus it appears highly likely that ABP proteins play a role in olfactory communication
A Candidate Subspecies Discrimination System Involving a Vomeronasal Receptor Gene with Different Alleles Fixed in M. m. domesticus and M. m. musculus
Assortative mating, a potentially efficient prezygotic reproductive barrier, may prevent loss of genetic potential by avoiding the production of unfit hybrids (i.e., because of hybrid infertility or hybrid breakdown) that occur at regions of secondary contact between incipient species. In the case of the mouse hybrid zone, where two subspecies of Mus musculus (M. m. domesticus and M. m. musculus) meet and exchange genes to a limited extent, assortative mating requires a means of subspecies recognition. We based the work reported here on the hypothesis that, if there is a pheromone sufficiently diverged between M. m. domesticus and M. m. musculus to mediate subspecies recognition, then that process must also require a specific receptor(s), also sufficiently diverged between the subspecies, to receive the signal and elicit an assortative mating response. We studied the mouse V1R genes, which encode a large family of receptors in the vomeronasal organ (VNO), by screening Perlegen SNP data and identified one, Vmn1r67, with 24 fixed SNP differences most of which (15/24) are nonsynonymous nucleotide substitutions between M. m. domesticus and M. m. musculus. We observed substantial linkage disequilibrium (LD) between Vmn1r67 and Abpa27, a mouse salivary androgen-binding protein gene that encodes a proteinaceous pheromone (ABP) capable of mediating assortative mating, perhaps in conjunction with its bound small lipophilic ligand. The LD we observed is likely a case of association rather than residual physical linkage from a very recent selective sweep, because an intervening gene, Vmn1r71, shows significant intra(sub)specific polymorphism but no inter(sub)specific divergence in its nucleotide sequence. We discuss alternative explanations of these observations, for example that Abpa27 and Vmn1r67 are coevolving as signal and receptor to reinforce subspecies hybridization barriers or that the unusually divergent Vmn1r67 allele was not a product of fast positive selection, but was derived from an introgressed allele, possibly from Mus spretus
Registration of \u27Manska\u27 Pubescent Intermediate Wheatgrass
\u27MANSKA\u27 pubescent intermediate wheatgrass [Thinopyrum intermedium subsp. barbulatum (Schur) Barkw. & Dewey] (Reg. no. CV-21, PI 562527) was tested as Mandan 12781 and released 16 April 1992 by the USDA-ARS in cooperation with the USDA-SCS; the Agricultural Research Division, Institute of Agriculture and Natural Resources, University of Nebraska; and the North Agricultural Experiment Station
In Defense of Wireless Carrier Sense
Carrier sense is often used to regulate concurrency in wireless medium access control (MAC) protocols, balancing interference protection and spatial reuse. Carrier sense is known to be imperfect, and many improved techniques have been proposed. Is the search for a replacement justified? This paper presents a theoretical model for average case two-sender carrier sense based on radio propagation theory and Shannon capacity. Analysis using the model shows that carrier sense performance is surprisingly close to optimal for radios with adaptive bitrate. The model suggests that hidden and exposed terminals usually cause modest reductions in throughput rather than dramatic decreases. Finally, it is possible to choose a fixed sense threshold which performs well across a wide range of scenarios, in large part due to the role of the noise floor. Experimental results from an indoor 802.11 testbed support these claims
Negative Feedback Regulation of HIV-1 by Gene Editing Strategy
The CRISPR/Cas9 gene editing method is comprised of the guide RNA (gRNA) to target a specific DNA sequence for cleavage and the Cas9 endonuclease for introducing breaks in the double-stranded DNA identified by the gRNA. Co-expression of both a multiplex of HIV-1-specific gRNAs and Cas9 in cells results in the modification and/or excision of the segment of viral DNA, leading to replication-defective virus. In this study, we have personalized the activity of CRISPR/Cas9 by placing the gene encoding Cas9 under the control of a minimal promoter of HIV-1 that is activated by the HIV-1 Tat protein. We demonstrate that functional activation of CRISPR/Cas9 by Tat during the course of viral infection excises the designated segment of the integrated viral DNA and consequently suppresses viral expression. This strategy was also used in a latently infected CD4+ T-cell model after treatment with a variety of HIV-1 stimulating agents including PMA and TSA. Controlled expression of Cas9 by Tat offers a new strategy for safe implementation of the Cas9 technology for ablation of HIV-1 at a very early stage of HIV-1 replication during the course of the acute phase of infection and the reactivation of silent proviral DNA in latently infected cells
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