1,309 research outputs found

    Effect of Salicylic Acid on the Early Development of the Chick Limb-Bud

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    Transplanted hind limb-buds of chick embryos were treated with salicylic acid. Treatment with this chemical caused reduction in length, weight and volume of the developing limb-buds. A side effect observed was an apparent loosening of the basal membrane and examined with regard to length, weight, and volume. The above observations are discussed in relation to the different hypotheses of the ectoderm-mesoderm interaction. The physiological role of the basal membrane, as well as the possible implications of the basal findings to the question of limb development and morphogenesis, are also discussed

    Energetic proton spectra in the 11 June 1991 solar flare

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    The June 11, 1991 gamma-ray flare seen by the Compton Gamma-ray Observatory (CGRO) displays several features that make it a dynamic and rich event. It is a member of a class of long duration gamma-ray events with both 2.223 MeV and greater than 8 MeV emission for hours after the impulsive phase. It also contains an inter-phase between the impulsive and extended phases that presents a challenge to the standard gamma-ray line (GRL) flare picture. This phase has strong 2.223 MeV emission and relatively weak 4.44 MeV emission indicative of a very hard parent proton spectrum. However, this would indicate emission greater than 8 MeV, which is absent from this period. We present the application of new spectroscopy techniques to this phase of the flare in order to present a reasonable explanation for this seemly inconsistent picture

    Energetic proton spectra in the 11 June 1991 solar flare

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    We have studied a subset of the 11 June 1991 solar flare γ-ray data that we believe arise from soft proton or ion spectra. Using data from the COMPTEL instrument on the Compton Observatory we discuss the gamma-ray intensities at 2.223 MeV, 4–7 MeV, and 8–30 MeV in terms of the parent proton spectrum responsible for the emission

    ASSESSMENT OF PERIODS OF SAND PRIMING AND HYDRO-PRIMING ON THE GERMINATION OF AFRICAN EBONY (Diospyros mespiliformis Hochst)

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    Diospyros mespiliformis (Hochst) is a multipurpose, agro-forestry tree species with diverse environmental and ecological significances. However, low percentage germination associated with its seeds has limited its domestication. To overcome this challenge, there is need to adopt cheap, fast, safe, natural and adoptable physiological techniques such as sand priming and hydro-priming. There is paucity of quantified information on natural and safe methods of relieving dormancy as sand priming and hydro-priming. Most of methods of breaking dormancy as use of acid are not simple, safe and adoptable by farmers who practices agro-forestry. In the light of this, these experiments were conducted to assess the periods of sand priming (0, 2, 4, 6 and 8 weeks) and hydro-priming (0, 2, 4, 6 and 8 weeks) on the germination of D. mespiliformis. Both experiments were laid down in completely randomized design with four replicates. Mean germination times were calculated, and result revealed that a significant increase in percentage germination was recorded with increasing periods of exposing seeds to sand priming up to four weeks. The percentage germination ranged between 28%-93.25% for control (0) and four weeks sand priming respectively. Least value of 8.92 day was recorded for mean germination time of control (0 sand priming). A significant increase in percentage germination was recorded with increasing hours of hydro-priming up to 24 hours. The percentage germination was ranged between 25% - 100% for control (0) hour to 24 hours. Highest germination percentages were recorded in seeds subjected to sand priming for 4weeks (93.25%) and those hydro-primed for 24hours (100%). These results are recommended for mass production of D. mespiliformis in agro-forestry nurseries. &nbsp

    Gamma ray measurements of the 1991 November 15 solar flare

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    The 1991 November 15 X1.5 flare was a well observed solar event. Comprehensive data from ground-based observatories and spacecraft provide the basis for a contextual interpretation of gamma-ray spectra from the Compton Gamma Ray Observatory (CGRO). In particular, spectral, spatial, and temporal data at several energies are necessary to understand the particle dynamics and the acceleration mechanism(s) within this flare. X-ray images, radio, Ca XIX data and magnetograms provide morphological information on the acceleration region [4,5], while gamma-ray spectral data provide information on the parent ion spectrum. Furthermore, time profiles in hard X-rays and gamma-rays provide valuable information on temporal characteristics of the energetic particles. We report the results of our analysis of the evolution of this flare as a function of energy (∼25 keV–2.5 MeV) and time. These results, together with other high energy data (e.g. from experiments on Yohkoh, Ulysses, and PVO) may assist in identifying and understanding the acceleration mechanism(s) taking place in this event

    X- and gamma-ray observations of the 15 November 1991 Solar Flare

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    This work expands the current understanding of the 15 November 1991 Solar Flare. The flare was a well observed event in radio to gamma-rays and is the first flare to be extensively studied with the benefit of detailed soft and hard X-ray images. In this work, we add data from all four instruments on the Compton Gamma Ray Observatory. Using these data we determined that the accelerated electron spectrum above 170 keV is best fit with a power law with a spectral index of −4.6, while the accelerated proton spectrum above 0.6 MeV is fit with a power law of spectral index −4.5. From this we computed lower limits for the energy content of these particles of∼1023 ergs (electrons) and ∼1027 ergs (ions above 0.6 MeV). These particles do not have enough energy to produce the white-light emission observed from this event. We computed a time constant of 26+20−15 s for the 2.223 MeV neutron capture line, which is consistent at the 2σ level with the lowest values of ∼70 s found for other flares. The mechanism for this short capture time may be better understood after analyses of high energy EGRET data that show potential evidence for pion emission near ∼100 MeV

    Relationship between serum level of ionized calcium, magnesium, phosphate, vitamin d and parathyroid hormone with stages of CKD.

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    Chronic kidney disease is defined as either damage or a decreased Glomerular Filtration Rate of less than 60ml/min/1.73m for 3 or more months. There is destruction of renal mass with irreversible sclerosis and loss of nephron leading to a progressive decline in GFR.Secondary hyperparathyroidism hyperphosphataemia, hypocalcaemia and vitamin-D deficiency are common complications of CKD. Objective: To determine relationship between serum level of ionised calcium, magnesium, phosphate, vitamin-D and parathyroid hormone with stages of CKD. Method: This study was conducted at ABUTH Zaria. 125 consecutive adult patients in various stages of CKD who presented were enrolled and 125 apparently healthy matched for sex and age controls were also recruited. Results: 9% of patients were in stage-1, 16% in stage-2, 22% in stage-3, 12% in stage-4 and 41% in stage-5. Serum ionised calcium, vitamin-D and eCrCl showed a progressive decline as the stage of CKD advances, while serum phosphate, creatinine and iPTH showed a progressive increase as the stage of CKD advances. Changes in serum magnesium showed a slight change with advancing stages of CKD. The difference in mean serum levels of calcium, phosphorus, vitamin-D, parathyroid hormone, creatinine and eCrCl with different stages of CKD were statistically significant. eCrCl correlated negatively with phosphate and iPTH while serum creatinine correlated negatively with calcium and positively with phosphate and iPTH. Conclusion: Majority of CKD patients were in late stage. Correlation of analytes with stages was more in late stages and biochemical derangements occurred in late, rather than early stages of CKD

    Recent rubella infection among childbearing women in a tertiary hospital in Nigeria: A seroepidemiological indication for vaccination need

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    Background: Congenital Rubella Infection can be prevented and future generation saved from  disability by protecting women of reproductive age through vaccination. The study is aimed at  determining serological evidence of recent rubella infection among women of childbearing age.Method: A cross sectional study was carried out among 285 women aged between 15 and 49 years. Enzyme immunoassay method was used to detect and quantify human IgM and IgG antibodies with avidity for Rubella virus in sera of participants. Socio-demographic characteristics of the subjects, along with recent history of fever, rash and adverse pregnancy outcome among others were obtained using a questionnaire. Statistical analysis was carried out using the program statistical package for social sciences (SPSS) version 16. Majority (78.3%) of the women recruited for the study were within 15-34 years age range. Of the 285 sera assayed for Rubella IgM antibodies, 23 (8.1%; 95% CI: 4.9%-11.3 %.) was IgM seropositive, while the remaining 262 (91.9%) were seronegative. A total of 7 (2.5%) of reproductive age women in Ilorin had a recent primary infection while 16 (5.6%) had a persistent Rubella infection or recent re-infection.In conclusion, there is need for vaccination of susceptible women of reproductive age in Ilorin as a large number of women have Rubella in their reproductive age.Keywords: Rubella, Immunoglobulin M, avidity, reproductive age, Ilorin, Nigeri
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