Cardiorespiratory effects of a 7° reverse Trendelenburg position in anaesthetized horses: a randomized clinical trial     

Stijn Schauvliege  Anna Binetti  Luc Duchateau  Jacoba Johanna van Dijk  Frank Gasthuys 《Veterinary anaesthesia and analgesia》2018,45(5):648-657

Objective

To evaluate the cardiorespiratory effects of a 7° reverse Trendelenburg position (RTP) in anaesthetized horses.

Study design

Randomized, non-blinded clinical trial.

Animals

A total of 125 horses undergoing elective surgery in dorsal recumbency.

Methods

Horses were allocated to one of three weight classes and assigned to be positioned either on a horizontal table or on a table in 7° RTP, according to a randomized block design. In all horses, anaesthesia was maintained with isoflurane in oxygen and a constant rate infusion of romifidine. All horses were mechanically ventilated throughout anaesthesia, and routine cardiovascular monitoring and arterial blood gas analysis were performed at 15-minute intervals and relevant variables calculated. Data from the first 60 minutes of anaesthesia were compared between both positions using a mixed model analysis of variance.

Results

A significant interaction was found between position and weight class for the alveolar to arterial oxygen tension gradient and F-shunt: these variables were lower in RTP than in horizontal position in the two lowest weight classes and vice versa in the highest weight class. Arterial oxygen tension and oxygenation indices were significantly worse in the horses in the higher weight classes.

Conclusions and clinical relevance

A 7° RTP did not result in clinically relevant changes in gas exchange or cardiovascular function. Horses with a higher body weight are at increased risk for hypoxaemia during anaesthesia in dorsal recumbency.  相似文献   

RADIX: rhizoslide platform allowing high throughput digital image analysis of root system expansion     

Chantal?Le Marié  Norbert?Kirchgessner  Patrick?Flütsch  Johannes?Pfeifer  Achim?Walter  Andreas?HundEmail author 《Plant methods》2016,12(1):40

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Effects of local-scale removals on feral swine populations in southern Texas     

Johanna Delgado-Acevedo  Randy W. DeYoung  Tyler A. Campbell 《国际虫害防治杂志》2013,59(2):122-127

Feral swine (Sus scrofa) are one of the most threatening mammalian pest species in North America owing to the damage they cause to natural habitats and agroecosystems, and the risk of disease transmission they pose to wildlife, livestock, and humans. The long-term (> 1 year) effects of lethal control efforts on feral swine populations at local scales are largely unknown. Using a panel of molecular markers, we assessed the effects of lethal control efforts on selected populations of feral swine in southern Texas. We collected tissue samples from two sites during removal campaigns, extracted and amplified DNA, and assessed population structure, genetic clustering, and immigration. We removed 145 individuals (9.7 swine per km²) at one site and 204 individuals (6.6 swine per km²) at another site. Fixation indices, Bayesian clustering, and assignment tests based on allele frequencies all produced similar results, indicating little or no differentiation among removals at either site. Localized feral swine removals aimed at reducing damage had no long-term impact on population parameters. Removals occurred at sites in which the swine groups were contiguous with neighboring feral swine family units and groups. This may have resulted in immigration of adjacent, but not genetically distinct, feral swine onto sites following the initial removals. To achieve long-term reduction of damage by feral swine populations, additional information is needed to enable genetic populations and corresponding management units to be defined.  相似文献   

A microplate assay to measure soil microbial biomass phosphorus     

Richard?Jeannotte  David?W.?Sommerville  Chantal?Hamel  Joann?K.?WhalenEmail author 《Biology and Fertility of Soils》2004,40(3):201-205

Quantification of phosphorus (P) concentrations in microbial biomass is required to better understand how P immobilization and turnover in soils are controlled by environmental and anthropogenic factors. Soil microbial biomass P (MBP) is generally extracted using the chloroform fumigation-direct extraction procedure and then analysed for P using the ammonium molybdate-ascorbic acid method on a flow injection analysis (FIA) system. Our objective was to determine whether a microscale malachite green method on a microplate system would provide as accurate MBP analysis as the ascorbic acid method on an FIA system. Twelve soils were collected from agricultural fields in southwestern Quebec, fumigated with chloroform and extracted with 0.5 M NaHCO₃ (pH 8.5). The dissolved inorganic phosphorus (DIP) concentration in fumigated soils was not affected by the method of analysis, and results from the two systems of analysis were significantly correlated (r =0.998, P <0.05). The MBP concentrations in these agricultural soils were between 0.36 and 60.05 g P g^–1, consistent with other published values. Our results indicate that MBP can be assessed equally well with the malachite green method using a microplate system as with the ascorbic acid method on an FIA system. The microplate system is rapid and requires smaller volumes of samples and reagents than the FIA system, thus reducing the quantity of waste produced. We conclude that the microscale malachite green method could be applied to measure the MBP concentration in a wide range of soils with good sensitivity, reproducibility and accuracy.  相似文献   

Toward an environmental predictor of tuna recruitment     

Phoebe A. Woodworth‐Jefcoats  Johanna L. K. Wren 《Fisheries Oceanography》2020,29(5):436-441

Bigeye tuna are of global economic importance and are the primary target species of Hawaii's most valuable commercial fishery. Due to their high commercial value, bigeye tuna are relatively well studied and routinely assessed. Larval and adult bigeye surveys have been conducted for many years and are supported by ongoing research on their physiology and life history. Yet, modeling stock dynamics and estimating future catch rates remain challenging. Here, we show that an appropriately lagged measure of phytoplankton size is a robust predictor of catch rates in Hawaii's bigeye tuna fishery with a forecast window of four years. We present a fishery‐independent tool with the potential to improve stock assessments, aid dynamic fisheries management, and allow Hawaii's commercial longline fishing industry to better plan for the future.  相似文献   

Methacarn preserves mucus integrity and improves visualization of amoebae in gills of Atlantic salmon (Salmo salar L.)     

Carolina Fernandez  Dario Mascolo  Sean J. Monaghan  Johanna L. Baily  Lynn Chalmers  Giuseppe Paladini  Alexandra Adams  James E. Bron  Sophie Fridman 《Journal of fish diseases》2019,42(6):883-894

Two aqueous fixation methods (modified Davidson's solution and modified Davidson's solution with 2% (w/v) Alcian blue) were compared against two non‐aqueous fixation methods (methacarn solution and methacarn solution with 2% (w/v) Alcian blue) along with the standard buffered formalin fixation method to (a) improve preservation of the mucous coat on Atlantic salmon, Salmo salar L., gills and (b) to examine the interaction between the amoebae and mucus on the gill during an infection with amoebic gill disease. Aqueous fixatives demonstrated excellent cytological preservation but failed to deliver the preservation of the mucus when compared to the non‐aqueous‐based fixatives; qualitative and semi‐quantitative analysis revealed a greater preservation of the gill mucus using the non‐aqueous methacarn solution. A combination of this fixation method and an Alcian blue/Periodic acid–Schiff staining was tested in gills of Atlantic salmon infected with amoebic gill disease; lectin labelling was also used to confirm the mucus preservation in the methacarn‐fixed tissue. Amoebae were observed closely associated with the mucus demonstrating that the techniques employed for preservation of the mucous coat can indeed avoid the loss of potential mucus‐embedded parasites, thus providing a better understanding of the relationship between the mucus and parasite.  相似文献   

Genetic differentiation between and within ecotypes of pike (Esox lucius) in the Baltic Sea     

Oscar Nordahl  Per Koch‐Schmidt  Johanna Sunde  Yeerin Y&#x;ld&#x;r&#x;m  Petter Tibblin  Anders Forsman  Per Larsson 《水产资源保护:海洋与淡水生态系统》2019,29(11):1923-1935

The effect of energy reserves and cryoprotectants on overwintering mortality in Mercenaria mercenaria notata (Say 1822) at two tidal levels     

Chantal Gionet  Elise Mayrand  Thomas Landry 《Aquaculture International》2009,17(6):589-605

The objective of this study is to identify possible causes of the high winter mortality noted in juvenile Mercenaria mercenaria notata in eastern Canada. The percentage mortality, shell growth, concentration of energy reserves, and production of cryoprotectant molecules were compared between notata and native quahogs kept at intertidal and subtidal levels. Overwintering mortality of the notata strain reached 47.2% and was 3–9 times higher than that of the native strain. Shell increment was higher in the native than in the notata strain and also at the intertidal than at the subtidal level. The quahogs from the subtidal zone had a higher concentration of protein than those from the intertidal zone in August and April but a lower concentration in February. The notata strain had a lower concentration of lipids and glucose (34.9 and 0.21 mg g⁻¹ dry weight) than the native strain (42.2 and 0.28 mg g⁻¹ dry weight). Thermal hysteresis was detected in none of the quahog groups. High winter mortality in the notata strain seems to be caused, in part, by a lower capacity to stock lipid compared with the native strain. The higher concentration of glucose in the native strain may favour survival in cold water by helping to reduce the freezing point of the animals’ fluids.  相似文献   

Can within field yield variation be explained using horizontal penetrometer resistance and electrical conductivity measurements? Results from three Swedish fields     

Elisabeth Bölenius  Johanna Wetterlind  Thomas Keller 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2018,68(8):690-700

Spatial variations in yield occur in all agricultural fields to some degree. Knowledge of the reasons for these variations, especially temporally stable yield patterns, is needed in order to improve productivity by changing production methods or inputs. This information must be provided in a simple, cost-effective way. This study investigated whether field-scale measurements of penetration resistance (PR) could identify temporally stable yield patterns without complementary measurements of other properties. The PR measurements were also compared with field-scale apparent electrical conductivity (ECa) measurements and correlations between yield and PR and yield and ECa were investigated. Measurements with a newly constructed horizontal penetrometer and a non-invasive proximal electromagnetic induction sensor were carried out in three fields in east-central Sweden. The measurements were made once in each field, apart from one field where PR was measured twice in one season. The sensor measurements were compared with crop yield measured over the course of several years. The horizontal penetrometer was able to identify low-yielding areas in one field. However, single measurements of PR or ECa were insufficient to consistently identify yield variations. Parts of the fields showed more consistent patterns, with stronger correlations between PR, ECa and yield. PR and ECa data were better at explaining yield variations in drier years, but showed diverging patterns in different fields and neither showed a much stronger correlation to yield than the other. In future studies, simultaneous measurement of soil water content is recommended and also PR measurements at a water content drier than field capacity.  相似文献   

Pre-cultivation of Scots pine and Norway spruce transplant seedlings under four different light spectra did not affect their field performance     

Johanna Riikonen 《New Forests》2016,47(4):607-619

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