A Technique for Estimating Rangeland Canopy-Gap Size Distributions From High-Resolution Digital Imagery

The amount and distribution of gaps in vegetation canopy is a useful indicator of multiple ecosystem processes and functions. In this paper, we describe a semiautomated approach for estimating canopy-gap size distributions in rangelands from high-resolution (HR) digital images using image interpretation by observers and statistical image classification techniques. We considered two different classification methods (maximum-likelihood classification and logistic regression) and both pixel-based and object-based approaches to estimate canopy-gap size distributions from 2- to 3-cm resolution UltraCamX color infrared aerial photographs for arid and semiarid shrub sites in Idaho, Nevada, and New Mexico. We compare our image-based estimates to field-based measurements for the study sites. Generally, percent of input points correctly classified and kappa coefficients of agreement for plot image classifications was very high. Plots with low kappa values yielded canopy gap estimates that were very different from field-based estimates. We found a strong relationship (R² > 0.9 for all four methods evaluated) between image- and field-based estimates of the total percent of the plot in canopy gaps greater than 50 cm for plots with a classification kappa of greater than 0.5. Performance of the remote sensing techniques varied for small canopy gaps (25 to 50 cm) but were very similar for moderate (50 to 200 cm) and large (> 200 cm) canopy gaps. Our results demonstrate that canopy-gap size distributions can be reliably estimated from HR imagery in a variety of plant community types. Additionally, we suggest that classification goodness-of-fit measures are a potentially useful tool for identifying and screening out plots where precision of estimates from imagery may be low. We conclude that classification of HR imagery based on observer-interpreted training points and image classification is a viable technique for estimating canopy gap size distributions. Our results are consistent with other research that has looked at the ability to derive monitoring indicators from HR imagery.     

Cefquinome Concentrations in Endometrium after Intrauterine Treatment of Cobactan 4.5%® in Mares and Inflammatory Response of the Endometrium to this Treatment

This study was conducted to measure the concentration of cefquinome in the endometrium of mares after intrauterine treatment and to evaluate associated inflammation. Mares (n = 14) were randomly assigned to one of the following groups: (i) control (n = 4) were either not treated (n = 2) or received (n = 2) lactated Ringer's intrauterine for 1 or 3 days; (ii) treated mares (n = 10) received intrauterine cefquinome for 1 or 3 days. After at least 10 days had passed following the last treatment and ovulation, mares were given Prostaglandin F2α (PGF2α) and were randomly assigned to an alternate treatment. Endometrial biopsy samples were taken at 2, 8, 24 and 48 h, or at 4, 12 and 36 h, after the last treatment. Biopsy samples were taken at the same time points from control mares (n = 2) and lactated Ringer-treated mares (n = 2). Cefquinome concentrations were quantified using a high-performance liquid chromatography (HPLC) assay and inflammation was assessed using haematoxylin and eosin (H&E)-stained sections. Concentrations of cefquinome [559 (1 day) and 595 μg/g (3 days) at 2 h, and 403 (1 day) and 370 μg/g (3 days) at 4 h] were similar between treatment groups at 2 and 4 h after treatment (p > 0.05). At 8 h, as well as at 24 and 48 h, concentrations were greater in the 3-day group (17 vs 301 μg/g, 3 vs 80 μg/g and 0.1 vs 0.2 μg/g, respectively) (p < 0.05). No significant differences (p > 0.05) in the inflammatory response at 2–48 h after treatment were found between groups.     

Consistency in pest risk analysis – how can it be achieved and what are the benefits?*

This paper describes the efforts in the PRATIQUE EU project to increase consistency that were integrated into the revised EPPO Decision‐support scheme (DSS) for Pest Risk Analysis (PRA). The establishment section is used here to illustrate the changes and improvements of the DSS, as it has undergone the most comprehensive changes with reformulation and restructuring of many questions and detailed rating guidance. When revising the establishment section of the EPPO DSS for PRA, there were three principal objectives that influenced the revision: (i) to focus the assessment on the most relevant factors influencing establishment; (ii) to identify the area where establishment is possible before assessing the suitability of that area, and (iii) to enhance the consistency of the establishment section by providing rating guidance with sub‐questions and examples. To simplify the process, some questions were rephrased as closed questions (answer is either yes or no). Clearer notes were provided to explain what information is needed to answer the questions. Furthermore, consistency has been enhanced by developing tools to help assessors when deciding on an appropriate overall risk rating and uncertainty score by providing a visual summary of the risk ratings and uncertainty scores (‘Visualizer’) and a method for integrating all the responses to the questions to provide a summary score for each major section and an overall assessment of risk (‘Rule based matrix model’).     

Food-borne human pathogenic viruses and their molecular detection with special consideration of noroviruses and hepatitis A virus in mussels

Viruses are increasingly important as etiological agents of gastrointestinal infections. Because of improved diagnostic methods, in particular, because of molecular biological techniques, viruses can be detected much more frequently as pathogens of foodborne diseases. Apart from the hepatitis A virus (HAV) the Norovirus (NLV) is becoming more significant. On an international level methods are developed to detect the amount of viruses which minimise PCR inhibitors and which are applicable in routine diagnostic. There are numerous routines available in the field of virus diagnostic in shellfish and oysters which are, however, not yet standardised and applicable in the whole of Europe. This review highlights viral agents their characteristics as well as food contaminated with viruses. While most of the detection methods are cited from the literature, own preliminary results of virus detection in mussels are discussed in addition.     

Generation of reactive oxygen species by a novel anthraquinone derivative in the cyanobacterium Planktothrix perornata (Skuja)

A water-soluble anthraquinone derivative (2-[methylamino-N-(1′-methylethyl)]-9,10-anthraquinone monophosphate), previously found to be selectively toxic towards Planktothrix perornata at submicromolar concentrations, was studied to determine its toxic mode of action towards this cyanobacterium. Chlorophyll fluorescence was monitored as an indicator of photosynthetic efficiency, and measurement of reactive oxygen species (ROS) was performed using the ROS-sensitive probe 2′,7′-dichlorodihydrofluorescein diacetate. The effects of the herbicide paraquat (a ROS generator) as well as ascorbate and α-tocopherol (ROS scavengers) on ROS formation by P. perornata were studied. Also, the effects of different concentrations of ascorbate, α-tocopherol, and the herbicide diuron on reducing the toxicity of the water-soluble anthraquinone derivative towards P. perornata were determined. Our results indicate that the water-soluble anthraquinone derivative does not inhibit photosynthetic electron transport directly, but does generate ROS at levels that may cause toxicity towards P. perornata.     

洋葱染色体核型的FISH分析

 挑选洋葱(Allium cepa L．) (2n=2x=16，CC)有丝分裂中期细胞，以洋葱卫星DNA序列(AC—SAT-DNA)为探针，DIG-1 1-dUTP为标记物，用荧光原位杂交(FISH)方法观察其在染色体上的定位，并进行洋葱的核型分析。6号染色体为近端部着丝点染色体，在其长臂末端有一个卫星DNA序列的主要位点。其余每条染色体在其长、短臂的末端都各具有一个主要位点。差异表现在各染色体上卫星DNA序列的次要位点分布不同。根据洋葱8对染色体各自具有的独特的卫星DNA分布位点，可将洋葱8对染色体全部分开。以此为基础，构建了洋葱卫星DNA在染色体上分布的模式图。     

Factors associated with low vitamin D status of Australian alpacas

Objective To investigate factors associated with low vitamin D status of alpacas at pasture in southern Australia. Design A 2‐year survey of alpacas from two farms in South Australia and three in Victoria. Blood samples were collected from 20 to 30 alpacas on each farm on five occasions each year. Breed, gender, age and fleece colour of animals were recorded. Method Blood samples were assayed for plasma 2.5‐hydroxycholecalciferol (25‐OH D₃) and plasma inorganic phosphorus (Pi). Data sets from 802 animal samples were analysed by multiple regression to determine variables associated with low vitamin D status of alpacas. The relationship between plasma 25‐OH D₃ and plasma Pi was also investigated. Results Vitamin D status was significantly affected by month of sampling, with low values in late winter and high values in summer. Plasma vitamin D concentrations increased with age, were higher in alpacas with light fleeces than in those with dark fleeces and were also higher in the Suri than in the Huacaya breed. Plasma Pi concentrations were generally lower in alpacas with plasma 25‐OH D₃ values < 25 nmol/L. Conclusions Young alpacas with dark fleeces are most at risk from vitamin D insufficiency in late winter in southern Australia. The present study indicates that plasma Pi values are not a reliable indicator of vitamin D status of alpacas as assessed by plasma 25‐OH D₃ concentrations.