Exploring multiple viewshed analysis using terrain features and optimisation techniques

The calculation of viewsheds is a routine operation in geographic information systems and is used in a wide range of applications. Many of these involve the siting of features, such as radio masts, which are part of a network and yet the selection of sites is normally done separately for each feature. The selection of a series of locations which collectively maximise the visual coverage of an area is a combinatorial problem and as such cannot be directly solved except for trivial cases. In this paper, two strategies for tackling this problem are explored. The first is to restrict the search to key topographic points in the landscape such as peaks, pits and passes. The second is to use heuristics which have been applied to other maximal coverage spatial problems such as location-allocation. The results show that the use of these two strategies results in a reduction of the computing time necessary by two orders of magnitude, but at the cost of a loss of 10% in the area viewed. Three different heuristics were used, of which Simulated Annealing produced the best results. However the improvement over a much simpler fast-descent swap heuristic was very slight, but at the cost of greatly increased running times. © 2004 Elsevier Ltd. All rights reserved

Adjusting DICOM specifications when using wireless LANs: The MedLAN example

Wireless networks will become increasingly useful in point-of-care areas such as hospitals, because of their ease of use and their flexibility. A system called MedLAN has been developed by the Central Middlesex Hospital and Brunei University to take advantage of the above desirable properties of WLANs for use in accident & emergency departments to broadcast live, high quality video images and sound over a LAN or the Internet. However, in many cases, the limited available throughput of such a WLAN system makes the use of high demanding specifications, such as DICOM, problematic especially when using no compression during transmission. In this paper we will present some practical results when combining low compression with wireless LANs. We will conclude with the assessment of images and sounds by several doctors showing that the system we have devised is very useful in this setting

Proteoglycan neofunctions: regulation of inflammation and autophagy in cancer biology.

Inflammation and autophagy have emerged as prominent issues in the context of proteoglycan signaling. In particular, two small, leucine-rich proteoglycans, biglycan and decorin, play pivotal roles in the regulation of these vital cellular pathways and, as such, are intrinsically involved in cancer initiation and progression. In this minireview, we will address novel functions of biglycan and decorin in inflammation and autophagy, and analyze new emerging signaling events triggered by these proteoglycans, which directly or indirectly modulate these processes. We will critically discuss the dual role of proteoglycan-driven inflammation and autophagy in tumor biology, and delineate the potential mechanisms through which soluble extracellular matrix constituents affect the microenvironment associated with inflammatory and neoplastic diseases

Synthesis of ozone from air via a polymer-electrolyte-membrane cell with a doped tin oxide anode

The generation of ozone from air using an electrochemical cell consisting of an air cathode, a polymer-electrolyte-membrane (PEM), and a doped tin oxide anode is reported. This synthesis is environmentally friendly compared to the conventional high-voltage corona discharge process since NOx formation is eliminated; a higher ozone concentration is generated; and lower energy may be required. © The Royal Society of Chemistry 2006.postprin

Ectoparasites of Sheep and Goats in North-West Amhara Regional State, Ethiopia

A cross-sectional study on ectoparasites of sheep (n=738) and goats (n=492) was conducted in Northwestern Amhara Regional State of Ethiopia from October 2009 to April 2010 to determine the prevalence of major ectoparasites of sheep and goats and the associated risk factors. Out of the clinically examined animals, 331(44.9%) sheep and 214 (43.5%) goats were infested with one or more ectoparasites. Ectoparasites identified in sheep were Damalinia ovis (30.9%), Mellophagus ovinus (10.8%), ticks (3.9%), Linognathus species (3.1%) and flea (1.1%). Among goats, Linognathus species, ticks, flea and demodectic mange were identified with respective prevalence of 27%, 17.7%, 2.6% and 2.2%. Sheep in midland were 3.7 and 2.3 times more at risk for Damalinia ovis infestation than sheep in highland and lowland, respectively and also goats in midland were 1.8 times at risk for Linognathus species than lowland sheep (P < 0.05). Sheep poor in body condition were 1.9 times more at risk for Damalinia ovis than good body condition sheep and goats poor in body condition were 3.5 times more at risk for Linognathus species than good body condition goats (P< 0.05). Age and wool length of sheep were important predictors for the presences of Mellophagus ovinus on highland sheep. The prevalence of Mellophagus ovinus was significantly higher in young and long wool sheep than in adult and short wool sheep (P < 0.05). The observed overall prevalence is generally high which may result in enormous economic losses through decreased production and productivity, damages to the skin and deaths of the animal which requires an immediate attention and professional intervention.Key words: Ectoparasites, Ethiopia, Goat, Prevalence, Risk factors, Sheep

Reply to "Comment on 'Long-term atmospheric measurements of C1-C5 alkyl nitrates in the Pearl River Delta region of southeast China'"

Department of Civil and Environmental Engineerin

CD4⁺ T-cell plasticity in non-infectious retinal inflammatory disease

Non-infectious uveitis (NIU) is a potentially sight-threatening disease. Effector CD4+ T cells, especially interferon-γ-(IFNγ) producing Th1 cells and interleukin-17-(IL-17) producing Th17 cells, are the major immunopathogenic cells, as demonstrated by adoptive transfer of disease in a model of experimental autoimmune uveitis (EAU). CD4+FoxP3+CD25+ regulatory T cells (Tregs) were known to suppress function of effector CD4+ T cells and contribute to resolution of disease. It has been recently reported that some CD4+ T-cell subsets demonstrate shared phenotypes with another CD4+ T-cell subset, offering the potential for dual function. For example, Th17/Th1 (co-expressing IFNγ and IL-17) cells and Th17/Treg (co-expressing IL-17 and FoxP3) cells have been identified in NIU and EAU. In this review, we have investigated the evidence as to whether these ‘plastic CD4+ T cells’ are functionally active in uveitis. We conclude that Th17/Th1 cells are generated locally, are resistant to the immunosuppressive effects of steroids, and contribute to early development of EAU. Th17/Treg cells produce IL-17, not IL-10, and act similar to Th17 cells. These cells were considered pathogenic in uveitis. Future studies are needed to better clarify their function, and in the future, these cell subsets may in need to be taken into consideration for designing treatment strategies for disease

Discrimination of foreign speech pitch and autistic traits in non-clinical population

Individuals with Autism Spectrum Conditions (ASC) are widely suggested to show enhanced perceptual discrimination but inconsistent findings have been reported for pitch discrimination. Given the high variability in ASC, this study investigated whether ASC traits were correlated with pitch discrimination in an undergraduate sample when musical and language experiences were taken into consideration. Results indicated that the Social Skills subscale of the Autism Spectrum Quotient (AQ) was associated with foreign speech pitch discrimination, suggesting that individuals who were less sociable and socially skillful were less able to discriminate foreign speech pitch. Current findings have an implication in investigating individual differences in ASC and further investigation is needed for spelling out the relationship between the non-social and social aspects of ASC