scholarly journals Monitoring methods and spatial patterns of European canker disease in commercial orchards

2016 ◽  
Vol 69 ◽  
pp. 213-220 ◽  
Author(s):  
R.E. Campbell ◽  
S. Roy ◽  
T. Curnow ◽  
M. Walter
Keyword(s):  
Spatial Pattern ◽  
Disease Control ◽  
Spatial Patterns ◽  
Disease Incidence ◽  
Systematic Sampling ◽  
Monitoring Methods ◽  
Canker Disease ◽  
Single Row ◽  
Changes Over Time ◽  
Over Time

European canker (Neonectria ditissima) kills trees and decreases production in apple orchards To determine a level of disease control or the extent of its spread in commercial orchards efficient monitoring methods are required In this study we investigated two monitoring methods sampling a single row and systematic sampling of an orchard block The spatial pattern of disease within blocks and whether this changes over time was also investigated The accuracy of singlerow monitoring depended on the level of canker in the orchard and the patchiness of the distribution of infected trees However singlerow monitoring tracked changes over time in incidence severity and type of canker sufficiently well and was efficient The spatial patterns of disease incidence across the blocks were nonrandom but showed hotspots which did not change significantly over time

scholarly journals Dynamics of Lettuce Drop Incidence and Sclerotinia minor Inoculum Under Varied Crop Rotations

Plant Disease ◽  
2006 ◽  
Vol 90 (3) ◽  
pp. 269-278 ◽  
Author(s):  
J. J. Hao ◽  
K. V. Subbarao
Keyword(s):  
Spatial Pattern ◽  
Spatial Patterns ◽  
Field Experiments ◽  
Disease Incidence ◽  
Inoculum Density ◽  
Crop Rotations ◽  
Sclerotinia Minor ◽  
Progressive Decline ◽  
Fallow Period ◽  
Lettuce Drop

Field experiments were conducted to determine the population dynamics of Sclerotinia minor and incidence of lettuce drop at two sites during 1995 to 1998. Rotation treatments at the Spence site, which had a low density of inoculum (<7 sclerotia per 100 cm3 of soil) that was distributed randomly, included: continuous lettuce (LLL), lettuce rotated with broccoli (LBL), and lettuce followed by a fallow period (LFL). Treatments at the Hartnell site, which had a high density of inoculum (>7 sclerotia per 100 cm3 of soil) that was distributed uniformly, included: continuous lettuce (LLLL), alternate crops of broccoli and lettuce (BLBL), continuous broccoli or lettuce (BBLL), and fallow-lettuce-fallow-lettuce (FLFL). Under continuous lettuce cropping (LLLL) at the Hartnell site, a progressively aggregated spatial pattern of inoculum distribution developed, despite the initial uniform distribution of high inoculum density. In the fallow treatment (FLFL), the spatial pattern tended to be aggregated following a lettuce crop and less aggregated or random when left fallow. In contrast to these two treatments, treatments involving rotations with broccoli (BLBL and BBLL) exhibited consistently random spatial patterns of inoculum regardless of the crop in the field. The marginal increases in the number of sclerotia contributed by the few diseased lettuce plants were offset by the significant reductions in the number of sclerotia by the broccoli residue. Spatial patterns of disease incidence reflected the pattern of inoculum distribution in the soil at the Hartnell site. Higher inoculum density coupled with an aggregated distribution was associated with an aggregation in disease incidence. At Spence, this correlation was poor in most seasons because of progressive decline in the lettuce drop incidence and lack of treatment differences. In greenhouse experiments, the competence volume for S. minor sclerotia was quantified, which was calculated to be 25 3 for 100% infection and 200 cm3 for 50% infection. Thus, in 100 cm3 of soil, a minimum of four to five sclerotia are needed for 100% of infection, explaining the high correlation between inoculum density and disease incidence.

Spatial patterns and spread of exotic earthworms at local scales

2015 ◽  
Vol 93 (9) ◽  
pp. 721-726 ◽  
Author(s):  
Erin K. Cameron ◽  
Erin M. Bayne
Keyword(s):  
Spatial Patterns ◽  
Native Species ◽  
Spatial Scales ◽  
Local Level ◽  
Long Distance ◽  
Invasive Spread ◽  
Exotic Earthworms ◽  
Changes Over Time ◽  
Northeastern Alberta ◽  
Over Time

Given the substantial impacts of non-native species on invaded systems, an understanding of the rates and spatial patterns of invasive spread is critical. Spread may vary across spatial scales, with dispersal of invasive species occurring both via diffusive spread at local sites and long-distance jump dispersal at larger scales. Research on earthworm invasions in North American forests has focused on patterns of spread across landscapes, with less examination of spread at local sites. We sampled the exotic earthworm Dendrobaena octaedra (Savigny, 1826) on 500 m × 500 m grids at three sites in the boreal forest of northeastern Alberta in 2006 and again in 2012–2013 to examine distributional changes over time. Earthworms spread farther from roads (the presumed site of initial introduction) over time, and spatial patterns at our sites suggest transport by vehicles and waterways are key vectors of dispersal at the local level. Spread was estimated to be occurring at a rate of at least 17.9 m/year. Our study indicates that both diffusive spread and jump dispersal of earthworms can be important at local scales and that local diffusive spread may be substantially higher than previously estimated.

scholarly journals Spatial Pattern Analysis of Sharka Disease (Plum pox virus Strain M) in Peach Orchards of Southern France

2003 ◽  
Vol 93 (12) ◽  
pp. 1543-1552 ◽  
Author(s):  
Sylvie Dallot ◽  
Tim Gottwald ◽  
Gérard Labonne ◽  
Jean-Bernard Quiot
Keyword(s):  
Spatial Pattern ◽  
Spatial Patterns ◽  
Disease Incidence ◽  
Point Pattern ◽  
Plum Pox Virus ◽  
Spatial Pattern Analysis ◽  
Individual Tree ◽  
Southern France ◽  
Wide Range ◽  
Sharka Disease

The spatial pattern of Sharka disease, caused by Plum pox virus (PPV) strain M, was investigated in 18 peach plots located in two areas of southern France. PPV infections were monitored visually for each individual tree during one to three consecutive years. Point pattern and correlation-type approaches were undertaken using the binary data directly or after parsing them in contiguous quadrats of 4, 9, and 16 trees. Ordinary runs generally revealed a low but variable proportion of rows with adjacent symptomatic trees. Aggregation of disease incidence was indicated by the θ parameter of the beta-binomial distribution and related indices in 15 of the 18 plots tested for at least one assessment date of each. When aggregation was detected, it was indicated at all quadrat sizes and tended to be a function of disease incidence, as shown by the binary form of Taylor's power law. Spatial analysis by distance indices (SADIE) showed a nonrandom arrangement of quadrats with infected trees in 14 plots. The detection of patch clusters enclosing quadrats with above-average density of symptomatic trees, ellipsoidal in shape and generally extending from 4 to 14 trees within rows and from 4 to 10 trees perpendicular to the rows, could be interpreted as local areas of influence of PPV spread. Spatial patterns at the plot scale were often characterized by the occurrence of several clusters of infected trees located up to 90 m apart in the direction of the rows. When several time assessments were available, increasing clustering over time was generally evidenced by stronger values of the clustering index and by increasing patch cluster size. The combination of the different approaches revealed a wide range of spatial patterns of PPV-M, from no aggregation to high aggregation of symptomatic trees at all spatial scales investigated. Such patterns suggested that aphid transmission to neighboring trees occurred frequently but was not systematic. The mechanism of primary virus introduction, the age and structure of the orchards when infected, and the diversity of vector species probably had a strong influence on the secondary spread of the disease. This study provides a more complete understanding of PPV-M patterns which could help to improve targeting of removal of PPV-infected trees for more effective disease control.

Comparison of two devices for measuring exercise transcutaneous oxygen pressures in patients with claudication

VASA ◽  
2015 ◽  
Vol 44 (5) ◽  
pp. 355-362 ◽  
Author(s):  
Marie Urban ◽  
Alban Fouasson-Chailloux ◽  
Isabelle Signolet ◽  
Christophe Colas Ribas ◽  
Mathieu Feuilloy ◽  
...  
Keyword(s):  
Oxygen Pressure ◽  
Optical Sensors ◽  
Chemical Sensors ◽  
Transcutaneous Oxygen ◽  
Starting Values ◽  
Two Systems ◽  
Transcutaneous Oxygen Pressure ◽  
New Sensors ◽  
Changes Over Time ◽  
Over Time

Abstract. Summary: Background: We aimed at estimating the agreement between the Medicap® (photo-optical) and Radiometer® (electro-chemical) sensors during exercise transcutaneous oxygen pressure (tcpO2) tests. Our hypothesis was that although absolute starting values (tcpO2rest: mean over 2 minutes) might be different, tcpO2-changes over time and the minimal value of the decrease from rest of oxygen pressure (DROPmin) results at exercise shall be concordant between the two systems. Patients and methods: Forty seven patients with arterial claudication (65 + / - 7 years) performed a treadmill test with 5 probes each of the electro-chemical and photo-optical devices simultaneously, one of each system on the chest, on each buttock and on each calf. Results: Seventeen Medicap® probes disconnected during the tests. tcpO2rest and DROPmin values were higher with Medicap® than with Radiometer®, by 13.7 + / - 17.1 mm Hg and 3.4 + / - 11.7 mm Hg, respectively. Despite the differences in absolute starting values, changes over time were similar between the two systems. The concordance between the two systems was approximately 70 % for classification of test results from DROPmin. Conclusions: Photo-optical sensors are promising alternatives to electro-chemical sensors for exercise oximetry, provided that miniaturisation and weight reduction of the new sensors are possible.

Neuropsychological Symptoms in Posttraumatic Stress Disorder and Changes Over Time

2007 ◽  
Author(s):  
Miranda Olff ◽  
Mirjam Nijdam ◽  
Kristin Samuelson ◽  
Julia Golier ◽  
Mariel Meewisse ◽  
...  
Keyword(s):  
Posttraumatic Stress Disorder ◽  
Posttraumatic Stress ◽  
Stress Disorder ◽  
Neuropsychological Symptoms ◽  
Changes Over Time ◽  
Over Time

Changes Over Time in Adaptive Behavior Functioning of Twice-Exceptional Children

2010 ◽  
Author(s):  
Rebecca D. Stinson ◽  
Zachary Sussman ◽  
Megan Foley Nicpon ◽  
Allison L. Allmon ◽  
Courtney Cornick ◽  
...  
Keyword(s):  
Adaptive Behavior ◽  
Exceptional Children ◽  
Twice Exceptional ◽  
Changes Over Time ◽  
Over Time

Kategorisierung der Schädelform des Cavalier King Charles Spaniels

2019 ◽  
Vol 47 (02) ◽  
pp. 133-133
Keyword(s):  
Pilot Study ◽  
Cavalier King Charles Spaniel ◽  
Conformation Changes ◽  
Veterinary Record ◽  
Changes Over Time ◽  
Over Time

Knowler SP, Gillstedt L, Mitchell TJ et al. Pilot study of head conformation changes over time in the Cavalier King Charles spaniel breed. Veterinary Record 2019. doi:10.1136/vr.105135.

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