Isolation of Mycobacterium bovis from brushtail possums with non-visible lesions     

GW de Lisle  GF Yates  JD Coleman 《New Zealand veterinary journal》2013,61(4):221-224

AIM: To determine the prevalence of Mycobacterium bovis infection in brushtail possums (Trichosurus vulpecula) that did not have macroscopic lesions of bovine tuberculosis, and to evaluate culture of pooled tissues from multiple possums as a method for determining the M. bovis-infection status of wildlife populations in New Zealand.

METHODS: Pools of selected tissues were collected from possums from four different populations known to be infected with M. bovis. Tissue pools from individual animals, and combined pools from multiple animals, were cultured for M. bovis.

RESULTS: In the four populations investigated, the prevalence of possums with macroscopic lesions confirmed by culture to be infected with M. bovis ranged from 1 to 19 (mean 31/283; 10.9)%. The prevalence of possums with non-visible lesions that were culture positive for M. bovis in the same populations ranged from 4 to 10 (mean 24/283; 8.5)%. The mean of the log10 cfu of M. bovis of the macroscopic lesions and of the culture-positive samples that did not have visible lesions was 3.85 (SE 0.26) and 1.46 (SE 0.26) log₁₀ cfu, respectively (p<0.01). Mycobacterium bovis was cultured from pools of 30–50 animals in the four populations studied.

CONCLUSIONS: The finding of M. bovis infection in possums with non-visible lesions identified a potential deficiency of declaring possum populations free of M. bovis on the basis of absence of macroscopic lesions. The culturing of pools of selected tissues from multiple animals without visible lesions can be used to reduce laboratory costs of possum surveys without a major reduction in the ability to detect M. bovis infection.  相似文献   

Odonata enter the biodiversity crisis debate: The first global assessment of an insect group     

Viola Clausnitzer  Vincent J. Kalkman  Ben Collen  Matja? Bedjani?  Klaas-Douwe B. Dijkstra  John Hawking  Elena Malikova  Kai Schütte  Reagan J. Villanueva  Keith Wilson 《Biological conservation》2009,142(8):1864-1869

The status and trends of global biodiversity are often measured with a bias towards datasets limited to terrestrial vertebrates. The first global assessment of an insect order (Odonata) provides new context to the ongoing discussion of current biodiversity loss. A randomly selected sample of 1500 (26.4%) of the 5680 described dragonflies and damselflies was assessed using IUCN’s Red List criteria. Distribution maps for each species were created and species were assigned to habitat types. These data were analysed in respect to threat level for regions and habitat types. We have found that one in 10 species of dragonflies and damselflies is threatened with extinction. This threat level is among the lowest of groups that have been assessed to date, suggesting that previous estimates of extinction risk for insects might be misleading. However, Odonata only comprise a small invertebrate order, with above-average dispersal ability and relatively wide distribution ranges. For conservation science and policy to be truly representative of global biodiversity a representative cross-section of invertebrates needs to be included.  相似文献   

History of atmospheric lead deposition since 12,370 (14)C yr BP from a peat bog, jura mountains, switzerland   总被引：3，自引：0，他引：3  

W Shotyk  D Weiss  PG Appleby  AK Cheburkin  RFM Gloor  JD Kramers  S Reese  Van Der Knaap WO 《Science (New York, N.Y.)》1998,281(5383):1635-1640

A continuous record of atmospheric lead since 12,370 carbon-14 years before the present (14C yr BP) is preserved in a Swiss peat bog. Enhanced fluxes caused by climate changes reached their maxima 10, 590 (14)C yr BP (Younger Dryas) and 8230 (14)C yr BP. Soil erosion caused by forest clearing and agricultural tillage increased lead deposition after 5320 (14)C yr BP. Increasing lead/scandium and decreasing lead-206/lead-207 beginning 3000 (14)C yr BP indicate the beginning of lead pollution from mining and smelting, and anthropogenic sources have dominated lead emissions ever since. The greatest lead flux (15.7 milligrams per square meter per year in A.D. 1979) was 1570 times the natural, background value (0.01 milligram per square meter per year from 8030 to 5320 (14)C yr BP).  相似文献   

Evaluating resistant brassica trap crops to manage Heterodera schachtii (Schmidt) infestations in eastern England     

Alistair JD Wright  Matthew A Back  Mark Stevens  Debbie L Sparkes 《Pest management science》2019,75(2):438-443

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Design of Nonionic Surfactants for Supercritical Carbon Dioxide     

JB McClain  DE Betts  DA Canelas  ET Samulski  JM DeSimone  JD Londono  HD Cochran  GD Wignall  D Chillura-Martino  R Triolo 《Science (New York, N.Y.)》1996,274(5295):2049-2052

Interfacially active block copolymer amphiphiles have been synthesized and their self-assembly into micelles in supercritical carbon dioxide (CO2) has been demonstrated with small-angle neutron scattering (SANS). These materials establish the design criteria for molecularly engineered surfactants that can stabilize and disperse otherwise insoluble matter into a CO2 continuous phase. Polystyrene-b-poly(1,1-dihydroperfluorooctyl acrylate) copolymers self-assembled into polydisperse core-shell-type micelles as a result of the disparate solubility characteristics of the different block segments in CO2. These nonionic surfactants for CO2 were shown by SANS to be capable of emulsifying up to 20 percent by weight of a CO2-insoluble hydrocarbon into CO2. This result demonstrates the efficacy of surfactant-modified CO2 in reducing the large volumes of organic and halogenated solvent waste streams released into our environment by solvent-intensive manufacturing and process industries.  相似文献   

The Impact of Solar Variability on Climate   总被引：5，自引：0，他引：5  

JD Haigh 《Science (New York, N.Y.)》1996,272(5264):981-984

A general circulation model that simulated changes in solar irradiance and stratospheric ozone was used to investigate the response of the atmosphere to the 11-year solar activity cycle. At solar maximum, a warming of the summer stratosphere was found to strengthen easterly winds, which penetrated into the equatorial upper troposphere, causing poleward shifts in the positions of the subtropical westerly jets, broadening of the tropical Hadley circulations, and poleward shifts of the storm tracks. These effects are similar to, although generally smaller in magnitude than, those observed in nature. A simulation in which only solar irradiance was changed showed a much weaker response.  相似文献   

CALCIUM CARBONATE AS AN ANTACID FOR ORAL PENICILLIN     

Seeberg VP  Collen MF 《Science (New York, N.Y.)》1945,102(2644):225-227

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The utility of screening diagnostic tests in identifying associative immune-mediated haemolytic anaemia in dogs     

GM Woodward  JD White 《Australian veterinary journal》2020,98(12):586-590

The study aimed to (1) define the proportion of dogs with immune-mediated haemolytic anaemia (IMHA) that have associative and non-associative disease and (2) evaluate the utility of screening diagnostic tests in identifying potential triggers of associative IMHA. Medical records of 78 dogs diagnosed with IMHA at a specialist hospital in Sydney from July 2008 to August 2017 were reviewed. The original diagnosis was revised according to published guidelines (Garden et al., 2019) as either diagnostic, supportive or suspicious for IMHA. Associative IMHA was confirmed if immunosuppressive therapy was discontinued within six weeks of effective treatment of a potential trigger. Associative IMHA was considered possible when a potential trigger was identified but its significance could not be confirmed. Associative IMHA was confirmed (3) or suspected (7) in 10 dogs (13%, confidence interval [CI] 7.1%–22%), with 68 cases presumed to be non-associative. Associative IMHA was present in 3/29 (10.3%) of dogs with criteria diagnostic for IMHA, 4/42 (9.5%) of dogs with criteria supportive for IMHA and 3/7 (42.9%) of dogs with criteria suspicious for IMHA. Abdominal ultrasound was performed in 68 dogs and identified possible triggers in five (7.3%, CI 3.2% to 16%). Thoracic radiographs were performed in 70 dogs but did not identify any potential triggers (0%, CI 0% to 5.2%). Urine culture was performed in 22 dogs and was positive in three (14%, CI 4.7% to 33.3%). Routine screening tests, particularly thoracic radiographs, have a low yield in identifying potential triggers of associative IMHA, but are more likely to be useful in dogs fulfilling less stringent diagnostic criteria of IMHA.  相似文献   

The effects of pre-anesthetic administration of xylazine on the cardiovascular responses to dobutamine in halothane anaesthetized horses     

RM McMurphy  CM Egger  JD Lillich 《Veterinary anaesthesia and analgesia》2003,30(2):95-96

Studies evaluating the effects of dobutamine in horses do not consistently report increases in cardiac output despite increases in arterial blood pressure. The concurrent administration of the α₂ agonist clonidine, in people, inhibited the chronotropic effects of dobutamine and increased left ventricular stroke work ( Zimpfer et al. 1982 ). Our study was performed to determine if pre‐medication with an α₂ agonist affects the response to dobutamine in anaesthetized horses. Eleven horses were anaesthetized on four separate occasions for one of four randomly assigned treatments; (I) no xylazine, no dobutamine (II) xylazine, no dobutamine (III) no xylazine, dobutamine, and (IV) xylazine, dobutamine. Horses received 0.02 mg kg^?1 of butorphanol IV 10 minutes prior to anesthetic induction. Two minutes prior to induction, groups II and IV received 0.5 mg kg^?1 of IV xylazine. Anaesthesia was induced with 6–7 mg kg^?1 of thiopental and maintained with halothane. End‐tidal halothane concentrations were maintained between 1.1 and 1.2% in groups I and III, and 0.9–1.0% for groups II and IV. Heart rate, cardiac output, right atrial pressure, and systolic (SAP), diastolic (DAP) and mean (MAP) arterial pressure were recorded 30 minutes after beginning halothane anaesthesia (T10). Cardiac output was estimated using Lithium dilution ( Linton et al. 2000 ). Baseline measurements were repeated twice, at 5‐minute intervals (T5 and T0). At time 0 (T0), an IV infusion of either saline (100 mL hour^?1) or dobutamine (0.001 mg kg^?1 minute^?1) was started and data recorded at 5‐minute intervals for 30 minutes (T5 – T30). Stroke volume and systemic vascular resistance (SVR) were calculated. Data were analysed using repeated measures anova (p < 0.01 significant) and Newman–Keuls for multiple comparisons. Cardiac output and stroke volume increased over time in groups III and IV. Cardiac index was higher in groups III and IV than in groups I and II from T10 until completion of the study. Estimates of cardiac index at T30 for groups I–IV were 45 ± 9, 46 ± 11, 71 ± 11, and 78 ± 19 mL kg^?1 minute^?1, respectively (mean ± SD). Stroke index was higher in groups III and IV than in groups I and II from T15 to T30. Values for stroke index at T30 for groups I–IV were 0.98 ± 0.19, 1.11 ± 0.18, 1.46 ± 0.21, 1.74 ± 0.33 mL kg^?1. Heart rate decreased from T10–T30 in groups I and II. Heart rate was greater in groups I and III than in groups II and IV at T5 and T0. Values for heart rate at T0 for groups I–IV were 48 ± 5, 42 ± 5, 50 ± 4, 43 ± 4 beats minute^?1. Systolic arterial pressure, DAP and MAP were higher in groups III and IV than in groups I and II from T5 to T30. There were no differences in SVR between groups. Dobutamine at 0.001 mg kg^?1 minute^?1 increased cardiac output, blood pressure, and stroke volume. Premedication with xylazine at 0.5 mg kg^?1 did not appear to affect the response to dobutamine.  相似文献   

Long-term changes in fish populations of acid streams and lochs in galloway South West Scotland     

R. Harriman  B. R. S. Morrison  L. A. Caines  P. Collen  A. W. Watt 《Water, air, and soil pollution》1987,32(1-2):89-112

During 1978–79, and again in 1984, fish populations were surveyed in 22 lochs and 27 streams in Galloway, southwest Scotland. Chemical analyses of these waters and of bulk precipitation were made over the same period. The study area includes moorland catchments and catchments with young or semi-mature coniferous forest. Trout were not caught in nets set in 5 lochs which were known to contain fish in the past. Angling records also indicated a decline in catches and increased average weight of trout in two other lochs. Evidence for the decline in fish populations suggests that this process has occurred over a period of at least 50 yr. In fishless lochs and streams the levels of acidity and Al were in the range known to be toxic to fish. Stream acidity and sulphate concentrations were significantly higher in catchments with semi-mature coniferous forests. The available evidence for long-term acidification of Galloway lochs and streams is discussed and it is concluded that acid depositions are likely to be the major cause of changes in the status of fisheries in this region.  相似文献