4,232 research outputs found

    World Aquaculture: Environmental Impacts and Troubleshooting Alternatives

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    Aquaculture has been considered as an option to cope with the world food demand. However, criticisms have arisen around aquaculture, most of them related to the destruction of ecosystems such as mangrove forest to construct aquaculture farms, as well as the environmental impacts of the effluents on the receiving ecosystems. The inherent benefits of aquaculture such as massive food production and economical profits have led the scientific community to seek for diverse strategies to minimize the negative impacts, rather than just prohibiting the activity. Aquaculture is a possible panacea, but at present is also responsible for diverse problems related with the environmental health; however the new strategies proposed during the last decade have proven that it is possible to achieve a sustainable aquaculture, but such strategies should be supported and proclaimed by the different federal environmental agencies from all countries. Additionally there is an urgent need to improve legislation and regulation for aquaculture. Only under such scenario, aquaculture will be a sustainable practice

    The Radiative and Conductive Heat Exchange of a Cold Desert

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    The heat exchange during dry conditions in Curlew Valley for selected clear days is determined from recordings in 10 minute intervals. The two heat budget components, radiative exchange and heat flow in the soil, are studied in detail. Maximum surface temperature due to radiative exchange above, assuming no heat loss by other components, is determined. Reduction of surface temperature by heat conduction into the ground was calculated as a second step to solve the heat budget equation. Substantial heat flow throughout a day is restricted to the upper 10 em of the soil. Diffusivity of the soil was determined from soil temperature using phase and amplitude equations, of which the first gave better results

    Nitric Oxide Releasing Nanoparticles for Treatment of Candida Albicans Burn Infections

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    Candida albicans is a leading fungal cause of burn infections in hospital settings, and sepsis is one of the principle causes of death after a severe burn. The prevalence of invasive candidiasis in burn cases varies widely, but it accounts for 3–23% of severe infection with a mortality rate ranging from 14 to 70%. Therefore, it is imperative that we develop innovative therapeutics to which this fungus is unlikely to evolve resistance, thus curtailing the associated morbidity and mortality and ultimately improving our capacity to treat these infections. An inexpensive and stable nitric oxide (NO)-releasing nanoparticle (NO-np) platform has been recently developed. NO is known to have direct antifungal activity, modulate host immune responses and significantly regulate wound healing. In this study, we hypothesized that NO-np would be an effective therapy in the treatment of C. albicans burn infections. Using a murine burn model, NO-np demonstrated antifungal activity against C. albicans in vivo, most likely by arresting its growth and morphogenesis as demonstrated in vitro. NO-np demonstrated effective antimicrobial activity against yeast and filamentous forms of the fungus. Moreover, we showed that NO-np significantly accelerated the rate of wound healing in cutaneous burn infections when compared to controls. The histological evaluation of the affected tissue revealed that NO-np treatment modified leukocyte infiltration, minimized the fungal burden, and reduced collagen degradation, thus providing potential mechanisms for the therapeutics’ biological activity. Together, these data suggest that NO-np have the potential to serve as a novel topical antifungal which can be used for the treatment of cutaneous burn infections and wounds

    Using Abrupt Changes in Magnetic Susceptibility within Type-II Superconductors to Explore Global Decoherence Phenomena

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    A phenomenon of a periodic staircase of macroscopic jumps in the admitted magnetic field has been observed, as the magnitude of an externally applied magnetic field is smoothly increased or decreased upon a superconducting (SC) loop of type II niobium-titanium wire which is coated with a non-superconducting layer of copper. Large temperature spikes were observed to occur simultaneously with the jumps, suggesting brief transitions to the normal state, caused by en masse motions of Abrikosov vortices. An experiment that exploits this phenomenon to explore the global decoherence of a large superconducting system will be discussed, and preliminary data will be presented. Though further experimentation is required to determine the actual decoherence rate across the superconducting system, multiple classical processes are ruled out, suggesting that jumps in magnetic flux are fully quantum mechanical processes which may correspond to large group velocities within the global Cooper pair wavefunction.Comment: 13 pages, 4 figures, part of proceedings for FQMT 2011 conference in Prague, Czech Republi

    Confined photon modes with triangular symmetry in hexagonal microcavities in 2D photonic Crystals

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    We present theoretical and experimental studies of the size and thickness dependencies of the optical emission spectra from microcavities with hexagonal shape in films of two-dimensional photonic crystal. A semiclassical plane-wave model, which takes into account the electrodynamic properties of quasi-2D planar photonic microcavity, is developed to predict the eigenfrequencies of the confined photon modes as a function of both the hexagon-cavity size and the film thickness. Modes with two different symmetries, triangular and hexagonal, are critically analyzed. It is shown that the model of confined photon modes with triangular symmetry gives a better agreement between the predicted eigenmodes and the observed resonances.Comment: 14 pages, 6 figure

    Photo-strobo-acoustic Imaging at the Microscale by Laser-Induced Ultrasound

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    The combination of microfluidic technology and optical fluids characterization techniques has been recently applied to produce lab-on-a-chip systems. In the present work, bringing together the imaging technique called photoacoustic imaging (PAI) and microfluidic technology were implemented to obtain micro-scale imaging. Laser-induced ultrasound signals were measured from microdroplets produced in a simple T-junction microfluidic system. Single pulse laser images were produced as a result of the combination of the aforementioned techniques, allowing to obtain of geometrical information of the microdroplets and its spatial position.Comment: Manuscript in proces

    Use of brachytherapy in children with cancer: the search for an uncomplicated cure

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    Brachytherapy is a sophisticated radiation method in which radioisotopes are placed inside or at a short distance from the tumour. The volume of tissue that receives the prescribed dose of radiotherapy is therefore fairly small compared with that used in standard radiotherapy techniques. In paediatric oncology, this method of radiation delivery can have a favourable effect on several undesirable long-term side-effects that sometimes develop in children who receive radiotherapy, such as growth retardation and development of second primary tumours. Here, we describe the rationale for use of brachytherapy in children with cancer, the methods of the different brachytherapy techniques available, and the results obtained with several brachytherapy regimens in expert institutions throughout the world
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