146 research outputs found
The extranasal glioma - a cause of neonatal respiratory distress
Normal brain tissue in an abnonnal configuration, occurring at a site away from the cranial cavity, is temied an Extranasal Glioma. Since its first description in 1852 by Reid2, only 140 patients with this entity have been reported. Heterotopic brain tissue when present in a confined area may cause obstmction, pressure and pain. Its occurrence in the nasopharyngeal region is relatively rare and only 19 cases have been reported so far2, the majority presenting with respiratory distress in the early neonatal period. The objective of this report is to create an awareness amongst the physicians of the presentation and management of this condition
Successful surgical intervention of total anomalous pulmonary venous drainage in the third decade of life
Total anomalous pulmonary venous drainage (TAPVD) accounts for approximately 1.5% of all congenital heart diseases. It is usually diagnosed in the neonatal period and is rarely seen in adults. We report an unusual case of a patient with TAPVD who was successfully treated at the age of 28 years. We believe that this is the oldest person in the South Asian literature to undergo surgical correction of TAPVD
Interacting Modified Variable Chaplygin Gas in Non-flat Universe
A unified model of dark energy and matter is presented using the modified
variable Chaplygin gas for interacting dark energy in a non-flat universe. The
two entities interact with each other non-gravitationally which involves a
coupling constant. Due to dynamic interaction, the variation in this constant
arises that henceforth changes the equations of state of these quantities. We
have derived the effective equations of state corresponding to matter and dark
energy in this interacting model. Moreover, the case of phantom energy is
deduced by putting constraints on the parameters involved.Comment: 9 pages; Accepted for publication in European Physical Journal
Generalized Holographic Dark Energy Model
In this paper, the model of holographic Chaplygin gas has been extended to
two general cases: first is the case of modified variable Chaplygin gas and
secondly of the viscous generalized Chaplygin gas. The dynamics of the model
are expressed by the use of scalar fields and the scalar potentials.Comment: 12 pages, to appear in Eur. Phys. J.
Solar Radiation Maps
[EN]Solar maps are very interesting tools to describe the characteristics of a region from the solar radiation point of view, and can be applied in atmospheric sciences and for energy engineering. To make them possible, a solar radiation numerical model is proposed. This one allows us to estimate radiation values on any point on earth. The model takes into account the terrain surface conditions and the cast shadows. The procedure uses 2-D adaptive triangles meshes built refining according to surface and albedo characteristics. Solar irradiance values are obtained for clear sky conditions. Using clear sky index as a conversion factor, real sky values are computed in terms of irradiance or irradiation with a desired time step. Finally, the solar radiation maps are obtained for all the domain
Constraints on coupling constant between dark energy and dark matter
We have investigated constraints on the coupling between dark matter and the
interacting Chaplygin gas. Our results indicate that the coupling constant
between these two entities can take arbitrary values, which can be either
positive or negative, thus giving arbitrary freedom to the inter-conversion
between Chaplygin gas and dark matter. Thus our results indicate that the
restriction on the coupling constant occurs as a very special case. Our
analysis also supports the existence of phantom energy under certain conditions
on the coupling constant.Comment: 16 Pages, 3 figure
Dismissive and deceptive car dealerships create barriers to electric vehicle adoption at the point of sale
This study investigates the role of car dealerships in the electrification of passenger transport, namely their sales advice about the purchase and use of electric vehicles (EVs). Because most consumers do not have pre-existing knowledge of EVs, and current market conditions favour petrol and diesel vehicles, car dealership experiences may strongly influence EV purchasing decisions. Here we show that car dealerships pose a significant barrier at the point of sale due to a perceived lack of business case viability in relation to petrol and diesel vehicles. In 126 shopping experiences at 82 car dealerships across Denmark, Finland, Iceland, Norway, and Sweden, we find dealers were dismissive of EVs, misinformed shoppers on vehicle specifications, omitted EVs from the sales conversation and strongly oriented customers towards petrol and diesel vehicle options. Dealer’s technological orientation, willingness to sell, and displayed knowledge of EVs were the main contributors to likely purchase intentions. These findings combined with expert interviews suggest that government and industry signalling affect sales strategies and purchasing trends. Policy and business strategies that address barriers at the point of sale are needed to accelerate EV adoption
Depth-specific fluctuations of gene expression and protein abundance modulate the photophysiology in the seagrass Posidonia oceanica
Here we present the results of a multiple organizational level analysis conceived to identify acclimative/adaptive strategies exhibited by the seagrass Posidonia oceanica to the daily fluctuations in the light environment, at contrasting depths. We assessed changes in photophysiological parameters, leaf respiration, pigments, and protein and mRNA expression levels. The results show that the diel oscillations of P. oceanica photophysiological and respiratory responses were related to transcripts and proteins expression of the genes involved in those processes and that there was a response asynchrony between shallow and deep plants probably caused by the strong differences in the light environment. The photochemical pathway of energy use was more effective in shallow plants due to higher light availability, but these plants needed more investment in photoprotection and photorepair, requiring higher translation and protein synthesis than deep plants. The genetic differentiation between deep and shallow stands suggests the existence of locally adapted genotypes to contrasting light environments. The depth-specific diel rhythms of photosynthetic and respiratory processes, from molecular to physiological levels, must be considered in the management and conservation of these key coastal ecosystems.Portuguese funds from FCT - Foundation for Science and Technology [UID/Multi/04326/2013]; SZN PhD fellowship via the Open University; ESF COST Action Seagrass Productivity: From Genes to Ecosystem Management [ES0906]info:eu-repo/semantics/publishedVersio
Specific ion channels contribute to key elements of pathology during secondary degeneration following neurotrauma
Background: Following partial injury to the central nervous system, cells beyond the initial injury site undergo secondary degeneration, exacerbating loss of neurons, compact myelin and function. Changes in Ca 2+ flux are associated with metabolic and structural changes, but it is not yet clear how flux through specific ion channels contributes to the various pathologies. Here, partial optic nerve transection in adult female rats was used to model secondary degeneration. Treatment with combinations of three ion channel inhibitors was used as a tool to investigate which elements of oxidative and structural damage related to long term functional outcomes. The inhibitors employed were the voltage gated Ca 2+ channel inhibitor Lomerizine (Lom), the Ca 2+ permeable AMPA receptor inhibitor YM872 and the P2X 7 receptor inhibitor oxATP. Results: Following partial optic nerve transection, hyper-phosphorylation of Tau and acetylated tubulin immunoreactivity were increased, and Nogo-A immunoreactivity was decreased, indicating that axonal changes occurred acutely. All combinations of ion channel inhibitors reduced hyper-phosphorylation of Tau and increased Nogo-A immunoreactivity at day 3 after injury. However, only Lom/oxATP or all three inhibitors in combination significantly reduced acetylated tubulin immunoreactivity. Most combinations of ion channel inhibitors were effective in restoring the lengths of the paranode and the paranodal gap, indicative of the length of the node of Ranvier, following injury. However, only all three inhibitors in combination restored to normal Ankyrin G length at the node of Ranvier. Similarly, HNE immunoreactivity and loss of oligodendrocyte precursor cells were only limited by treatment with all three ion channel inhibitors in combination. Conclusions: Data indicate that inhibiting any of a range of ion channels preserves certain elements of axon and node structure and limits some oxidative damage following injury, whereas ionic flux through all three channels must be inhibited to prevent lipid peroxidation and preserve Ankyrin G distribution and OPCs
Hydroponic technologies
This open access book, written by world experts in aquaponics and related technologies, provides the authoritative and comprehensive overview of the key aquaculture and hydroponic and other integrated systems, socio-economic and environmental aspects. Aquaponic systems, which combine aquaculture and vegetable food production offer alternative technology solutions for a world that is increasingly under stress through population growth, urbanisation, water shortages, land and soil degradation, environmental pollution, world hunger and climate change.Hydroponics is a method to grow crops without soil, and as such, these systems are added to aquaculture components to create aquaponics systems. Thus, together with the recirculating aquaculture system (RAS), hydroponic production forms a key part of the aqua-agricultural system of aquaponics. Many different existing hydroponic technologies can be applied when designing aquaponics systems. This depends on the environmental and financial circumstances, the type of crop that is cultivated and the available space. This chapter provides an overview of different hydroponic types, including substrates, nutrients and nutrient solutions, and disinfection methods of the recirculating nutrient solutions
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