4,734 research outputs found

    Changes in soil characteristics under different aged plantations of Corsican pine (pinus nigra) at Chopwell Woodland Park, Gateshead, UK

    Get PDF
    This study examines the pedogenic processes and temporal changes occurring in soils across six different aged plantations of Corsican pine (Pinus nigra), which were otherwise similar in their environmental characteristics, including geology, slope angle and aspect, altitude and land use history. A representative soil profile was sampled, on a horizon basis, and a further 10 topsoil samples were collected, on a grid basis, from each plantation. Properties determined in the laboratory included pH, organic carbon content, particle size distribution, exchangeable base content (Ca, Mg, K, Na), total free and organically-bound iron content, and lead and zinc concentrations. Morphological and chemical changes within the soil profiles were examined to shed light on the processes and pathways of soil formation, and one-way analysis of variance (ANOVA) was used to compare topsoil characteristics between the different plantations. Morphological and chemical changes within the soil profiles indicated that organic matter accumulation and mor humus formation, acidification, clay translocation (lessivage) and incipient podzolisation were the dominant pedogenic processes. There are very few systematic age-related changes in soil morphological or physical and chemical characteristics, possibly due to a combination of young stand ages, high topsoil variability, soil mixing due to drainage operations and silvicultural practices. There are, however, a number of statistically significant but non-systematic differences in soil properties between the different aged plantation blocks. Possible associations between these differences and age-related litter production and root growth, and silvicultural operations such as understory control, plantation thinning and selective harvesting are explored

    Patterns of sex ratio in the oil-sardine, Sardinella longiceps Val., at Calicut

    Get PDF
    Categorising the fish according to maturity, montti of capture and length groups, the data on the sex distribution of the Indian oil-sardine (5flrrfwW/fl/ong'/fepj) collected at Calicut during 1959-60 to 1965-66 seasons are subjected to statistical tests to find outthe nature and cause of dominance of either sex, if any. For the immature fish the overall inference is that there may not be any significant difierences in the annual recruited population. In the adult fish the possibility of more males in May is suggested as due to the fact that the males may start maturing a little earlier than the females. The dominance of males in 140-150 mm group and that of females in 170-190 mm groups is brought about by differential growth, the females growing faster during June to October period. It is recommended that the size of each sample for sex ratio studies should be at least 50. Based on the earlier and the present studies of this author, It is indicated that 375 million ova can be expected from a tonne of adult biomass of the oil-sardine population

    A forecast for the ensuing oil-sardine fishery

    Get PDF
    The ability to foreca st the course of events likely to be encountered during the approaching fishery season enhances the value of fishery research in the eyes of those in the industry , As Simpson (1956) has put it, "Apart from the value to the industry of forecasting, predicting what is going to happen and checking it against the actual events is to the fishery biologist one form of the universal research tool of formulating a hypothesis and putting it to test

    Our pelagic fishery resources Present and potential harvest

    Get PDF
    The two primary divisions of the oceans are (1) the benthic and (2) the pelagic, the former referring to the ocean floor which supports the demersal resources and the latter, the entire column of water , accomodating the pelagic resources. The pelagic region is a part of the marine biocycle and geographically, it is divisible into Atlantic and Indo-Pacific. Ecologically, the pelagic realm can b e bifurcated as neritic (inshore) and oceanic (opens e a) provinces d epending on the depth to which light penetrates and to the extent and depth of the continental slop

    Efficient Computation of CMB anisotropies in closed FRW models

    Get PDF
    We implement the efficient line of sight method to calculate the anisotropy and polarization of the cosmic microwave background for scalar and tensor modes in almost-Friedmann-Robertson-Walker models with positive spatial curvature. We present new results for the polarization power spectra in such models.Comment: 4 pages, 1 figure. Corrected/updated references. Accepted by ApJ. For the F90 source code see http://www.mrao.cam.ac.uk/~aml1005/cmb

    Role of a Conserved Glutamate Residue in the \u3cem\u3eEscherichia coli\u3c/em\u3e SecA ATPase Mechanism

    Get PDF
    Escherichia coli SecA uses ATP to drive the transport of proteins across cell membranes. Glutamate 210 in the “DEVD” Walker B motif of the SecA ATP-binding site has been proposed as the catalytic base for ATP hydrolysis (Hunt, J. F., Weinkauf, S., Henry, L., Fak, J. J., McNicholas, P., Oliver, D. B., and Deisenhofer, J. (2002) Science 297, 2018–2026). Consistent with this hypothesis, we find that mutation of glutamate 210 to aspartate results in a 90-fold reduction of the ATP hydrolysis rate compared with wild type SecA, 0.3 s–1versus 27 s–1, respectively. SecA-E210D also releases ADP at a slower rate compared with wild type SecA, suggesting that in addition to serving as the catalytic base, glutamate 210 might aid turnover as well. Our results contradict an earlier report that proposed aspartate 133 as the catalytic base (Sato, K., Mori, H., Yoshida, M., and Mizushima, S. (1996) J. Biol. Chem. 271, 17439–17444). Re-evaluation of the SecA-D133N mutant used in that study confirms its loss of ATPase and membrane translocation activities, but surprisingly, the analogous SecA-D133A mutant retains full activity, revealing that this residue does not play a key role in catalysis

    How informed are bronchial asthma patients: a questionnaire based study in a tertiary care hospital

    Get PDF
    Background: Asthma has been considered as one of the most common chronic diseases worldwide. Asthma due to its effects on bronchial passage compromises the respiration and intern impairs the quality of life. Aim was to evaluate the knowledge of asthma among patients attending our tertiary care hospital.Methods: The patients were subjected to chest X-ray and spirometry followed by the knowledge on asthma questionnaire which consisted of 28 questions.Results: Out of 75 patients, aged between 18-80 years, majority were males. Out of 75 patients, 60 (80%) patients had obtained a total score below 10 out of the total of 28 score. The causative factors for asthma, 60 (80%) patients believed that asthma was due to allergy. Only 2-3 patients (3-4%) had knowledge of the underlying pathologic process during an asthma attack. Fifty nine (79%) patients were aware of the symptoms of asthma. However, only 10 (13%) patients knew about the early signs of worsening of asthma and only 14 (19%) patients could judge the severity of asthma. Only 5 (7%) patients knew which drug was for regular use and which was to be used if breathlessness occurred. Merely around 4-10 (5 to 13%) patients knew that asthma could be prevented by avoiding trigger factors and by taking medication regularly.Conclusions: A good level of knowledge about asthma and better practices are rigorously important to prevent asthma exacerbations. More comprehensive, regular and patient centred counselling programs will be beneficial in improving awareness of asthma
    corecore