34,351 research outputs found

    Two new notocotylid trematodes from birds in Tasmania and their life histories

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    Paramonostomum caeci n. sp., adults of which occur mainly in the intestinal caeca of Anas supereiliosa, Cygnus atratus and Polioeephalus polioeephalus, is described. It is considered to closely resemble P. malerisehi from which it differs in being only one-third the size, having a spinose tegument and a cirrus covered with tubercles. P. bursae n.sp., adults of which have been found inhabiting the bursa of Fabricius of Anas supereiliosa is described and considered to be most similar to P. alveatum and P. parvum but to differ from them in the distribution of its vitellaria, the position of its ovary relative to the testes and in having a greater number of uterine loops. The domestic duck, Anas platyrhynehos, was found to serve as an experimental host for both new species. A brackish water snail, Coxiella badgerensis, inhabiting Calverts Lagoon in southeast Tasmania serves as a natural intermediate host for P. caeci n.sp. and P. bursae n.sp. and also for two other undescribed notocotylids. Developmental stages (rediae, cercariae and metacercariae) of both new Paramonostomum species are described. The cercaria of P. caeci n. sp. belongs to the Imbricata group, and that of P. bursae n.sp. to the Yenchingensis group

    Two strigeoid trematodes, Apatemon (Apatemon) gracilis (Rudolphi, 1819) and Diploetomum (Dolichorchis)galaxiae n. sp., which encyst in the freshwater fish Galaxias auratus Johnston in Lake Crescent, Tasmania.

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    The metacercaria and adult of Apatemon (Apatemon) gracilis (Rudolphi) and Diplostomum (Dolichorchis) galaxiae n.sp. are described and figured. Metacercarial cysts of these species occur in different parts of the endemic fish Galaxias auratus: A. gracilis in the body cavity, orbit and vitreous humour, and D. galaxiae n.sp. visible as black spots ('black-spot disease') in the musculature of the body and head. A gracilis which has not previously been recorded from Australia occurs in the black duck, Anas superciliosa, while D. galaxiae n.sp. infects the white-faced heron, Ardea novaehollandiae. The domestic duck, Anas platyrhynchos, is much more susceptible to experimental infection by Apatemon gracilis than by D. galaxiae n.sp. Both flukes inhabit the upper small intestine of their bird hosts. The reproductive system of D. galaxiae n.sp. is amphitypic. D. galaxiae n.sp. most closely resembles D. heronei Srivastava, 1954 and D. ketupanensis Vidyarthi, 1937; a key to species in the sub-genus Dolichorchis is given

    The CCD and readout electronics for the OMC instrument on Integral

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    The Optical Monitoring Camera (OMC) on ESA's Integral gamma-ray astronomy satellite is devoted to optical wavelength observations simultaneously covering the same field-of-view as the gamma-ray and X-ray instruments. The OMC consists of a refracting telescope with a CCD as the imaging device in the focal plane. Here we describe the CCD and its associated readout electronics, in particular pointing out features of interest to users of the OMC instrument and its data

    Terrestrial laser scanning to deliver high-resolution topography of the upper Tarfala valley, arctic Sweden

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    Alpine valleys are experiencing rapidly changing physical, biological and geochemical processes as glacier masses diminish, snowfall patterns change and consequently as hillslopes and valley-floor landforms and sediments adjust. Measurement and understanding of these processes on a valley, landform and surface scale requires topographic data with sufficient spatial coverage and spatial resolution to resolve sources, fluxes and storages of sediment. Most ideally such topographic data will be of a resolution sufficient to resolve important spatial heterogeneity in land cover, topography and surface texture, for example. This study presents the first high-resolution (1 m grid cell size) and freely available topography for the upper part of the Tarfala valley, arctic Sweden. The topography was obtained using terrestrial laser scanning and a bespoke workflow is presented to most efficiently cover a 9.3 km2 area. The unprecedented spatial resolution of this topography, which is 15 times greater than that previously available, reveals a suite of alpine landforms. These landforms span multiple glacier forefields, a variety of bedrock surfaces, various hillslopes and types of mass movement, and valley floor glacial, fluvial and periglacial sediments, for example. Primary and second-order derivatives of this elevation data, and vertical transects are given and will assist future classification of landforms and thus assist future targeted field campaigns. Overall, this study presents (1) baseline data from which future re-surveys will enable quantitative analysis of a dynamic landscape, and (2) an efficient workflow that is readily transferable to any scientific study at any other site. Both of these project outputs will find widespread usage in future alpine studies

    Evaluation of the efficacy and safety of high dose short duration enrofloxacin treatment regimen for uncomplicated urinary tract infections in dogs.

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    BackgroundUncomplicated urinary tract infections (UTI) in dogs usually are treated with antimicrobial drugs for 10-14 days. Shorter duration antimicrobial regimens have been evaluated in human patients.HypothesisA high dose short duration (HDSD) enrofloxacin protocol administered to dogs with uncomplicated UTI will not be inferior to a 14-day treatment regimen with amoxicillin-clavulanic acid.AnimalsClient-owned adult, otherwise healthy dogs with aerobic bacterial urine culture yielding ≥ 10(3) CFU/mL of bacteria after cystocentesis.MethodsProspective, multicenter, controlled, randomized blinded clinical trial. Enrolled dogs were randomized to group 1 (enrofloxacin 18-20 mg/kg PO q24h for 3 days) or group 2 (amoxicillin-clavulanic acid 13.75-25 mg/kg PO q12h for 14 days). Urine cultures were obtained at days 0, 10, and 21. Microbiologic and clinical cure rates were evaluated 7 days after antimicrobial treatment was discontinued. Lower urinary tract signs and adverse events also were recorded.ResultsThere were 35 dogs in group 1 and 33 in group 2. The microbiologic cure rate was 77.1 and 81.2% for groups 1 and 2, respectively. The clinical cure rate was 88.6 and 87.9% for groups 1 and 2, respectively. Cure rates between groups did not differ according to the selected margin of noninferiority.Conclusions and clinical importanceHDSD enrofloxacin treatment was not inferior to a conventional amoxicillin-clavulanic acid protocol for the treatment of uncomplicated bacterial UTI in dogs. Further research is warranted to determine if this protocol will positively impact owner compliance and decrease the emergence of antimicrobial resistance

    Supernatants derived from chemotherapy-treated cancer cell lines can modify angiogenesis

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    BACKGROUND: There is evidence that tumours produce substances such as cytokines and microvesicular bodies bearing bioactive molecules, which support the carcinogenic process. Furthermore, chemotherapy has also been shown to modify these exudates and in doing so, neutralise their tumourigenic influence. METHODS: In the current study, we have investigated the effect of chemotherapy agents on modifying the cytokine profile and microvesicular cargo of supernatants derived from cancer cell lines. In addition, we have explored the effect of these tumour-derived supernatants on angiogenesis, and how chemotherapy can alter the supernatants rendering them less pro-angiogenic. RESULTS: Herein, we show that supernatants contain a rich cocktail of cytokines, a number of which are potent modulators of angiogenesis. They also contain microvesicular bodies containing RNA transcripts that code for proteins involved in transcription, immune modulation and angiogenesis. These supernatants altered intracellular signalling molecules in endothelial cells and significantly enhanced their tubulogenic character; however, this was severely compromised when supernatants from tumours treated with chemotherapy was used instead. CONCLUSION: This study suggests tumour exudates and bioactive material from tumours can influence cellular functions, and that treatment with some chemotherapy can serve to negate these pro-tumourigenic processes

    Ice cliff dynamics in the Everest region of the Central Himalaya

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    The importance of ice cliffs for glacier-scale ablation on debris-covered glaciers is now widely recognised. However, a paucity of data exists to describe the spatio-temporal distribution of ice cliffs. In this study we analysed the position and geometry of 8229 ice cliffs and 5582 supraglacial ponds on 14 glaciers in the Everest region between 2000 and 2015. We observed notable ice cliff and pond spatial coincidence. On average across our study glaciers, 77% of supraglacial pond area was associated with an adjacent ice cliff, and 49% of ice cliffs featured an adjacent supraglacial pond. The spatial density of ice cliffs was not directly related to glacier velocity, but did peak within zones of active ice. Furthermore, we found that ice cliff density was glacier-specific, temporally variable, and was positively correlated with surface lowering and decreasing debris thickness for individual glaciers. Ice cliffs predominantly had a north-facing (commonly north-westerly) aspect, which was independent of glacier flow direction, thereby signifying a strong solar radiation control on cliff evolution. Independent field observations indicated that cliff morphology was related to aspect, local debris thickness, and presence of a supraglacial pond, and highlighted the importance of surface runnel formation, which acts as a preferential pathway for meltwater and debris fluxes. Overall, by coupling remote sensing and in-situ observations it has been possible to capture local and glacier-scale ice cliff dynamics across 14 glaciers, which is necessary if explicit parameterisation of ice cliffs in dynamic glacier models is to be achieved

    Role of dissolved nitrate and phosphate in isolates of Mesodinium rubrum and toxin-producing Dinophysis acuminata

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    Mesodinium rubrum (as prey) is a critical component, in addition to light, for growth and toxin production by the mixotrophic dinoflagellate Dinophysis acuminata. Little is known, however, about the role that dissolved inorganic nutrients play in this predator-prey relationship and system toxicity. A series of experiments were conducted to investigate the possible uptake of dissolved nitrate and phosphate by (1) D. acuminata starved of prey, (2) D. acuminata feeding on M. rubrum, and (3) M. rubrum grown in nutritionally modified medium. All single-clone or mixed cultures were monitored for dissolved and particulate nutrient levels over the growth cycle, as well as for growth rate, biomass, and toxin production when appropriate. Dinophysis acuminata did not utilize dissolved nitrate or phosphate in the medium under nutrient-enriched or nutrientreduced regimes, in the absence or presence of prey, or during any growth phase monitored. Changes in particulate phosphorus and nitrogen in D. acuminata were instead strongly influenced by the consumption of M. rubrum prey, and these levels quickly stabilized once prey were no longer available. Mesodinium rubrum, in contrast, rapidly assimilated dissolved nitrate and phosphate, with maximum uptake rates of 1.38 pmol N cell(-1) d(-1) and 1.63 pmol P cell(-1) d(-1), respectively. While D. acuminata did not benefit directly from the dissolved nitrate and phosphate, its growth (0.37 +/- 0.01 d(-1)) and toxin production rates for okadaic acid, dinophysistoxin-1 and pectenotoxin-2 (0.1, 0.9 and 2.6 pg cell(-1) d(-1), respectively) were directly coupled to prey availability. These results suggest that while dissolved nitrate and phosphate do not have a direct effect on toxin production or retention by D. acuminata, these nutrient pools contribute to prey growth and biomass, thereby indirectly influencing D. acuminata blooms and overall toxins in the system
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