The architecture and fine structure of gill filaments in the brown mussel, Perna perna

For many years, bivalve molluscs have played a useful role in determining the impact of pollution on marine organisms. In the northern hemisphere, ecologists from countries subscribing to the International Mussel Watch have used toxin-mediated changes in the organs of Mytilus edulis, especially in the morphology of gill filaments, to indicate the biotoxicity of marine effluent. M. edulis is not indigenous to South African waters. For us to adopt a similar approach on the South African east coast, it is necessary to catalogue both the normal appearance and toxin-mediated changes in our local brown mussel Perna perna. In this study, the gill filaments from five healthy, adult brown mussels were studied by light and transmission electron microscopy. Special attention was paid to filament architecture, ennervation of filaments, number and type of cells populating filament epithelia and variations in epithelial cell morphology and cilia ultrastructure. Filament shape was maintained by thickened chi-tln and strategically placed smooth myocytes. The epithelium was populated with eight morphologically distinctive non-secretory, mucus secreting or sensory cell types in various stages of differentiation. Unmyelinated nerves were situated beneath six cell types. Significant differences in filament architecture and epithelial cell morphology were found between M. edulis and P. perna. It is hoped that this comprehensive description of normal P. perna gill filaments will provide a morphological baseline for local pollution impact studies

Double-rig shrimp trawling, its rigging, comparative efficiency and economics

A radical and revolutionary change from the hitherto employed shrimp trawling is reported for better productivity and economy in deep sea trawling with medium and large vessels. Studies carried out off Veraval with a 13.7 m. four seam shrimp trawl as conventional single-rig and two 6.8 m four seam shrimp trawls as double-rig from a 15.2 m fishing vessel showed an increase of 98% shrimp catch by double-rig over single-rig at 86.3 % of the power utilised by the latter. It has also been worked out, theoretically, how better this available power can be utilised for further improvement of catch. An increase of 15% head rope length in case of double-rig over the optimum single-rig gear of any vessel is recommended

One-boat midwater trawling with unequal panelled trawl

Results of the comparative efficiency studies with 10.5 m equal panelled and 10.3 m unequal panelled midwater trawls operated from 10.9 m wooden trawler are presented. Out of the two nets, the latter proved to be relatively good for the capture of off bottom and column fishes like pomfrets, seer, lactarius, catfish, silver bar, ribbon fish and an increase of 84.4% in total catch was observed

Economics of gill netting and two boat midwater trawling

The paper deals with the economic aspects of operation of gill netting and two boat midwater trawling conducted off Cochin. The data collected on two boat midwater trawling and gill netting during 1979 and 1980-81 are presented. Gill netting was profitable at the range of 17.5 and 25.2% while two midwater trawling was profitable at the rate of 18.5 %

Transition from a maternal to external nitrogen source in maize seedlings

Maximizing NO3− uptake during seedling development is important as it has a major influence on plant growth and yield. However, little is known about the processes leading to, and involved in, the initiation of root NO3− uptake capacity in developing seedlings. This study examines the physiological processes involved in root NO3− uptake and metabolism, to gain an understanding of how the NO3− uptake system responds to meet demand as maize seedlings transition from seed N use to external N capture. The concentrations of seed‐derived free amino acids within root and shoot tissues are initially high, but decrease rapidly until stabilizing eight days after imbibition (DAI). Similarly, shoot N% decreases, but does not stabilize until 12–13 DAI. Following the decrease in free amino acid concentrations, root NO3− uptake capacity increases until shoot N% stabilizes. The increase in root NO3− uptake capacity corresponds with a rapid rise in transcript levels of putative NO3− transporters, ZmNRT2.1 and ZmNRT2.2 . The processes underlying the increase in root NO3− uptake capacity to meet N demand provide an insight into the processes controlling N uptake

The Imprint of Gravitational Waves on the Cosmic Microwave Background

Long-wavelength gravitational waves can induce significant temperature anisotropy in the cosmic microwave background. Distinguishing this from anisotropy induced by energy density fluctuations is critical for testing inflationary cosmology and theories of large-scale structure formation. We describe full radiative transport calculations of the two contributions and show that they differ dramatically at angular scales below a few degrees. We show how anisotropy experiments probing large- and small-angular scales can combine to distinguish the imprint due to gravitational waves.Comment: 11 pages, Penn Preprint-UPR-

Knowledge regarding Hepatitis B among staff nurses

Hospital is a place to get cured from the suffering. Among the members of health team the nurses spend most of their time at the bed side and they are usually considered as angels at the mission of comforting patients. Hepatitis B is a potentially life-threatening viral infection caused by Hepatitis B virus. It can create both acute and chronic diseases and, deemed as a major and serious health problem in the developing countries like India. Materials and methods: The descriptive survey approach adopted in the study aimed to assess the knowledge regarding Hepatitis B infection and its prevention among staff nurses. Self administered structured knowledge questionnaire was developed on the basis of objectives of the study by reviewing the literature of relevant topics and discussion with experts. Result: The data obtained from 100 staff nurses indicated that majority of the subjects (61%) were in the age group of 21-28 years, 84% were females and 16 % males. More than half of the subjects (55%) were with B. Sc qualification 63% were having 1-5 year experience and 62% of subjects were having monthly income between Rs 10,001-20,000. Only 36% of the subjects acquired information from college/friends. Distribution of staff nurses according to their knowledge showed that 86% had adequate knowledge, 12% had moderate knowledge, and 2%had poor knowledge. Conclusion: Nurses have major role in preventive aspect than in curative aspects Nurse through the scientific knowledge and skills are able to collect the data from public. The study results will help the investigators as well as the public to update their knowledge by organizing education programme. Keywords: Hepatitis B, Prevention, Staff nurses

Coherent spin valve phenomena and electrical spin injection in ferromagnetic/semiconductor/ferromagnetic junctions

Coherent quantum transport in ferromagnetic/ semiconductor/ ferromagnetic junctions is studied theoretically within the Landauer framework of ballistic transport. We show that quantum coherence can have unexpected implications for spin injection and that some intuitive spintronic concepts which are founded in semi-classical physics no longer apply: A quantum spin-valve (QSV) effect occurs even in the absence of a net spin polarized current flowing through the device, unlike in the classical regime. The converse effect also arises, i.e. a zero spin-valve signal for a non-vanishing spin-current. We introduce new criteria useful for analyzing quantum and classical spin transport phenomena and the relationships between them. The effects on QSV behavior of spin-dependent electron transmission at the interfaces, interface Schottky barriers, Rashba spin-orbit coupling and temperature, are systematically investigated. While the signature of the QSV is found to be sensitive to temperature, interestingly, that of its converse is not. We argue that the QSV phenomenon can have important implications for the interpretation of spin-injection in quantum spintronic experiments with spin-valve geometries.Comment: 15 pages including 11 figures. To appear in PR

Three-dimensional reconstruction of coronary arteries and plaque morphology using CT angiography - comparison and registration with IVUS

Background: The aim of this study is to present a new methodology for three-dimensional (3D) reconstruction of coronary arteries and plaque morphology using Computed Tomography Angiography (CTA). Methods: The methodology is summarized in six stages: 1) pre-processing of the initial raw images, 2) rough estimation of the lumen and outer vessel wall borders and approximation of the vessel's centerline, 3) manual adaptation of plaque parameters, 4) accurate extraction of the luminal centerline, 5) detection of the lumen - outer vessel wall borders and calcium plaque region, and 6) finally 3D surface construction. Results: The methodology was compared to the estimations of a recently presented Intravascular Ultrasound (IVUS) plaque characterization method. The correlation coefficients for calcium volume, surface area, length and angle vessel were 0.79, 0.86, 0.95 and 0.88, respectively. Additionally, when comparing the inner and outer vessel wall volumes of the reconstructed arteries produced by IVUS and CTA the observed correlation was 0.87 and 0.83, respectively. Conclusions: The results indicated that the proposed methodology is fast and accurate and thus it is likely in the future to have applications in research and clinical arena

Understand, Desing, Act: Climate-proof your supply chain

Presentations of Understand, Desing, Act: Climate-proof your supply chain Module 1: Understand climate change Module 2: How is climate change affecting my supply chain Module 3: How can I manage the effects climate change in having on my supply chain? Module 4: How can I scale up climate smart agriculture? Module 5: How do I know my investment in climate smart agriculture is working? Module 6: How can I convince my company and others to work on CSA