Modulation transfer functions of A.C. servomechanism components

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Effect of physical parameters on the reaction of graphite with silica in vacuum

Effect of physical parameters on reduction of silica graphite mixtures under vacuum condition

Green Fluorescent Protein (GFP) in Vector Systems Played Sense Role of Epigenetic in Plants

The green fluorescent protein (GFP) of jellyfish (_Aequorea victoria_) has significant advantages over other reporter genes, because expression can be detected in living cells without any substrates. Recently, epigenetic phenomena are important to consider in plant biotechnology experiments for elucidate unknown mechanism. Therefore, soybean immature cotyledons were generated embryogenesis cells and engineered with two different gene constructs (pHV and pHVS) using gene gun method. Both constructs contain a gene conferring resistance to hygromycin (_hpt_) as a selective marker and a modified glycinin (11S globulin) gene (_V3-1_) as a target. However, sGFP(_S65T_) as a reporter gene was used only in pHVS as a reporter gene for study the relation between using sGFP(_S65T_) and gene silencing phenomena. Fluorescence microscopic was used for screening after the selection of hygromycin, identified clearly the expression of sGFP(_S65T_) in the transformed soybean embryos bombarded with the pHVS construct. Protein analysis was used to detect gene expression overall seeds using SDS-PAGE. Percentage of gene down regulation was highly in pHV construct compared with pHVS. Thus, sGFP(_S65T_) as a reporter gene in vector system may be play useful role for transgenic evaluation and avoid gene silencing in plants for the benefit of plant transformation system

Mycorrhizal development and effects on growth of the peanut (Arachis hypogaea L.)

The association between the growth of peanut (Arachis hypogaea L.) and arbuscular mycorrhizal (AM) fungi of the genus was investigated by measurements; • mycorrhizal status of Glomus spp in diverse substrate soil conditions. • mycorrhizal dependency and nutrient uptake. • potential for mycorrhizal biocontrol of a bacterial pathogen. • mycorrhizal response to salinity stress. •effect of fungicides on Glomus mosseae mycorrhizal association. Generally these investigations indicated that both the AM fungi Glomus mosseae and Glomusfasciculatum were infective to peanuts, but displayed a differential effectiveness depending on the soil microbial biomass content in the soil. Glomus mosseae gave the best overall results in improving peanut growth and therefore it was selected for peanut mycorrhization in further experiments. There appeared to be a threshold' phosphorus requirement level for nonmycorrhizal peanuts, below which relative mycorrhizal dependency of the peanut was inclined to be significantly pronounced. Glomus mosseae protected peanut seedlings against the pathogenic bacterium Erwinia carotovora, it suppressed the pathogen population, improved the nutritional status of the plant, decreased the susceptibility of peanut seedlings to the bacterial soft rot disease and significantly alleviated disease effects. The fungus also demonstrated an ability to reduce NaCl salt stress syndrome. Glomus mosseae/peanut association in soils treated with relatively high dosages of Aspor and Plantvax fungicides was seriously affected and did not improve peanut growth substantially and appears to result in the loss of mycorrhizal benefits. This study indicates that Glomus mosseae may be a potential component to improve peanut production in low-input sustainable agrosystems

Variation of Electrostatic Coupling and Investigation of Current Percolation Paths in Nanocrystalline Silicon Cross Transistors

Nanocrystalline silicon thin films are promising materials for the development of advanced Large Scale Integration compatible quantum-dot and single-electron charging devices. The films consist of nanometer-scale grains of crystalline silicon, separated by amorphous silicon or silicon dioxide grain boundaries up to a few nanometer thick. These films have been used to fabricate single-electron transistor and memory devices, where the grains form single-electron charging islands isolated by tunnel barriers formed by the grain boundaries. The grain boundary tunnel barrier isolating the grains is also of great importance, as this determines the extent of the electrostatic and tunnel coupling between different grains. These effects can lead to the nanocrystalline silicon thin film behaving as a system of coupled quantum dots.& more..

Impact of Macroeconomic Policies on Sudanese Economic Growth: Empirical Evidence via Switching Regression

This paper focuses on assessing the impact of macroeconomic policies on the expansion and contraction of Sudanese real GDP as well as the computation of the number and the expected duration of each for the period of the period 1960Q1-2017Q4. The main tools of analysis are Simple switching regression and Markov switching regression are. The unemployment growth rate is the regime-switching variable in addition to the growth rates of the nominal effective exchange rate, real money supply, current government expenditure, and development expenses as non-switching variables. Markov-switching regression also outweighs simple switching regression in terms of Akaike information criterion, and transition probabilities. Results show that monetary policy was effective between the period of 1960Q1-1976Q4 adding 1.2% of real value. This however is; contrary to the period 1977Q1-1997Q4 where 60% of real value has been lost and improved significantly in the course of 1998Q1-2017Q4, hence, missing only 1%. The effect of the unemployment rate on growth at the period of contraction is almost four-time of the expansion. The positive effect of development expenses combined with the negative impact of current expenditure on the growth rate reveals the efficacy of monetary policy over fiscal. The exchange rate operates as a shock absorber. The expected duration, and the probability of staying in contraction last more than the expansion

Malaria in Sudan: past, present and the future

Summary. Malaria is a major public health problem in Sudan and this is theleading cause of death. A lot of efforts are done recently to decrease theprevalence adopting the RBM initiative with its well known six elements.There is a new protocol for treatment which would be launched in June2004.Malaria Burden. Malaria in Sudan is a major public Health Problem. Itleads to an estimated 7.5- 10 million cases and 35000 deaths every year. Theburden of the disease on the health system is a reality. Out of the totaloutpatients’ attendance, admissions and deaths malaria represents 20- 40%, 30-50%and 15-20% respectively. These figures bring Sudan on the top of WHO /EMRO countries, as Sudan shouldered 50% of cases and 70% of deaths in theregion (WHO/EMRO). Malaria is endemic throughout the Sudan. Theendemicity level varies from hypo-endemic in the north - mesoendemic inthe central part and hyper-and holo-endemic in the south. (Map 1).Considering other factors which serve as a background for malaria in Sudan;metriological, human behavior and activities, status of the controlprogramme, country economic and social conditions, Sudan has beenstratified to 5 strata (Map2). It is worth to mention here that 80% of thepopulations are living in epidemic-prone area-unstable malaria transmission

Effect of plant growth regulators on callus induction and plant regeneration in tuber segment culture of potato (Solanum tuberosum L.) cultivar Diamant

The present study was conducted to investigate the effects of different concentrations and combinations of growth regulators on callus induction and plant regeneration of potato (Solanum tuberosum L.) cultivar Diamant. The tuber segments were used as explants and cultured on Murashige and Skoog (MS) medium supplemented with different concentrations of -naphthalene acetic acid(NAA), 2,4-Dichlorophenoxy acetic acid (2,4-D), benzyl adenine (BA) and thidiazeron (TDZ) alone and 2,4-D in combinations with BA for callus induction. The best degree for callus formation (6.0) wasobtained on MS medium supplemented with 2,4-D alone at 3.0 mg/l or 2,4-D in combination with BA both at 2.0 mg/l. MS media supplemented with different levels of BA and TDZ were employed for shootregeneration. MS medium containing 5.0 mg/l TDZ was the best for days to shoot initiation, the highest percentage of callus with shoot (81%) and highest number of shoot per callus (3.4). Callus derivedshoots were rooted most effectively in half-strength MS medium containing 0.5 mg/l IBA. The success of plant tissue culture for in vitro culture of potato was encouraged by acclimatization of the plantlets inthe greenhouse conditions. Regenerated plants were morphologically uniform with normal leaf shape and growth pattern

Callus formation and organogenesis of tomato (Lycopersicon esculentum Mill, C.V. Omdurman) induced by thidiazuron

In vitro culture response was assessed in tomato (Lycopersicon esculentum Mill. c. v. Omdurman) for optimum callus induction and plantlet  regeneration. Callus induction was achieved within seven to ten days directly on the cut surfaces of both hypocotyls and cotyledon explants cultured on Murashige and Skoog (MS) basal medium supplemented with -naphthalene acetic acid (NAA), 2,4-dichlorophenoxyacetic acid (2,4-D), Thidiazuron (TDZ) and benzyl adenine (BA) alone or in differentcombinations, but not in hormone free-medium. The highest callusing index (5.3) was obtained on hypocotyls explants cultured on MS medium supplemented with NAA at 0.5 mg/l followed by an index of 5.2 obtained from the same explant by using 0.1 mg/l NAA in combination with BAP at 0.5 mg/l. However, for the cotyledon explants, the highest callusing index (4.7) was obtained on MS medium supplemented with NAA at either 2.0 or 3.0 mg/l. After 8 weeks of culture, organogenesis was observed only on the explants cultured on medium containing different concentrations of TDZ alone or in combination with BAP. The best shoot formation (93%) was obtained for cotyledon explant callus induced on MS medium containing TDZ in combination with BAP both at 0.5 mg/l. The highest number(6) of shoot per explant was obtained when cotyledon explant callus was sub cultured on MS medium supplemented with 3.0 mg/l TDZ. Plain half strength of MS was found to be the best rooting medium, however, addition of IAA at 1.0 mg/l and IBA at 2.0 mg/l were found essential to induce highest number of roots (22.1 ± 0.9) and longer roots (11.0 ± 0.3 cm), respectively. This protocol would be useful to create somaclonal variation and utilize transgenic approaches for varietal improvement of tomato