scholarly journals A simple model describes development of early peaks in oomycete zoospore inoculum detected in southern UK outdoors horticultural reservoirs

2016 ◽  
Vol 69 (2) ◽  
Author(s):  
Tim R. Pettitt ◽  
Carsten Ambelas Skjøth
Keyword(s):  
Simple Relationship ◽  
Storage Tanks ◽  
First Order ◽  
Air Temperatures ◽  
Colony Forming Units ◽  
Winter Temperatures ◽  
Climatological Station ◽  
The Uk ◽  
Scenario Study ◽  
Water Borne

The numbers of water-borne oomycete propagules in outdoor reservoirs used in horticultural nurseries within the UK are investigated in this study. Water samples were recovered from 11 different horticultural nurseries in the southern UK during Jan–May in 2 “cool” years (2010 and 2013; winter temperatures 2.0 and 0.4°C below UK Met Office 30 year winter average, respectively) and 2 “warm” years (2008 and 2012; winter temperatures 1.2 and 0.9°C above UK Met Office 30 year winter average, respectively). Samples were analyzed for total number of oomycete colony forming units (CFU), predominantly members of the families Saprolegniaceae and Pythiaceae, and these were combined to give monthly mean counts. The numbers of CFU were investigated with respect to prevailing climate in the region: mean monthly air temperatures calculated by using daily observations from the nearest climatological station. The investigations show that the number of CFU during spring can be explained by a linear first-order equation and a statistically significant <em>r</em><sup>2</sup> value of 0.66 with the simple relationship: [<em>CFU</em>] = <em>a</em>(<em>T</em> − <em>T</em><span><em><sub>b</sub></em></span>) − <em>b</em>, where <em>a</em> is the rate of inoculum development with temperature <em>T</em>, and <em>b</em> is the baseload population at temperatures below <em>T</em><span><em><sub>b</sub></em></span>. Despite the majority of oomycete CFU detected being non-phytopathogenic members of the Saprolegniaceae, total oomycete CFU counts are still of considerable value as indicators of irrigation water treatment efficacy and cleanliness of storage tanks. The presence/absence of <em>Pythium</em> spp. was also determined for all samples tested, and <em>Pythium</em> CFU were found to be present in the majority, the exceptions all being particularly cold months (January and February 2010, and January 2008). A simple scenario study (+2 deg C) suggests that abundance of water-borne oomycetes during spring could be affected by increased temperatures due to climate change.

scholarly journals Microtopographic control on the ground thermal regime in ice wedge polygons

2018 ◽  
Vol 12 (6) ◽  
pp. 1957-1968 ◽  
Author(s):  
Charles J. Abolt ◽  
Michael H. Young ◽  
Adam L. Atchley ◽  
Dylan R. Harp
Keyword(s):  
Thermal Conditions ◽  
Ground Temperature ◽  
The Arctic ◽  
Near Surface ◽  
Hydrologic Processes ◽  
Ground Temperatures ◽  
Air Temperatures ◽  
Winter Temperatures ◽  
Ice Wedge ◽  
Prudhoe Bay

Abstract. The goal of this research is to constrain the influence of ice wedge polygon microtopography on near-surface ground temperatures. Ice wedge polygon microtopography is prone to rapid deformation in a changing climate, and cracking in the ice wedge depends on thermal conditions at the top of the permafrost; therefore, feedbacks between microtopography and ground temperature can shed light on the potential for future ice wedge cracking in the Arctic. We first report on a year of sub-daily ground temperature observations at 5 depths and 9 locations throughout a cluster of low-centered polygons near Prudhoe Bay, Alaska, and demonstrate that the rims become the coldest zone of the polygon during winter, due to thinner snowpack. We then calibrate a polygon-scale numerical model of coupled thermal and hydrologic processes against this dataset, achieving an RMSE of less than 1.1 ∘C between observed and simulated ground temperature. Finally, we conduct a sensitivity analysis of the model by systematically manipulating the height of the rims and the depth of the troughs and tracking the effects on ice wedge temperature. The results indicate that winter temperatures in the ice wedge are sensitive to both rim height and trough depth, but more sensitive to rim height. Rims act as preferential outlets of subsurface heat; increasing rim size decreases winter temperatures in the ice wedge. Deeper troughs lead to increased snow entrapment, promoting insulation of the ice wedge. The potential for ice wedge cracking is therefore reduced if rims are destroyed or if troughs subside, due to warmer conditions in the ice wedge. These findings can help explain the origins of secondary ice wedges in modern and ancient polygons. The findings also imply that the potential for re-establishing rims in modern thermokarst-affected terrain will be limited by reduced cracking activity in the ice wedges, even if regional air temperatures stabilize.

Water and Disease After Croydon: A Review of Water-borne and Water-associated Disease in the UK 1937?86

1987 ◽  
Vol 1 (1) ◽  
pp. 7-21 ◽  
Author(s):  
N. S. GALBRAITH ◽  
NICOLA J. BARRETT ◽  
ROSALIND STANWELL-SMITH
Keyword(s):  
The Uk ◽  
Water Borne

scholarly journals Mid-Devensian climate and landscape in England: new data from Finningley, South Yorkshire

2019 ◽  
Vol 6 (7) ◽  
pp. 190577
Author(s):  
Philip I. Buckland ◽  
Mark D. Bateman ◽  
Ole Bennike ◽  
Paul C. Buckland ◽  
Brian M. Chase ◽  
...  
Keyword(s):  
Ice Core ◽  
Cold Climate ◽  
Climate Conditions ◽  
Sufficient Detail ◽  
Winter Temperatures ◽  
Ice Core Record ◽  
Climatic Range ◽  
The One ◽  
The Uk ◽  
Moisture Conditions

While there is extensive evidence for the Late Devensian, less is known about Early and Middle Devensian (approx. 110–30 ka) climates and environments in the UK. The Greenland ice-core record suggests the UK should have endured multiple changes, but the terrestrial palaeo-record lacks sufficient detail for confirmation from sites in the British Isles. Data from deposits at Finningley, South Yorkshire, can help redress this. A channel with organic silts, dated 40 314–39 552 cal a BP, contained plant macrofossil and insect remains showing tundra with dwarf-shrub heath and bare ground. Soil moisture conditions varied from free draining to riparian, with ponds and wetter vegetated areas. The climate was probably low arctic with snow cover during the winter. Mutual climatic range (MCR), based on Coleoptera, shows the mean monthly winter temperatures of −22 to −2°C and summer ones of 8–14°C. Periglacial structures within the basal gravel deposits and beyond the glacial limits indicate cold-climate conditions, including permafrost. A compilation of MCR reconstructions for other Middle Devensian English sites shows that marine isotope stage 3—between 59 and 28 ka—experienced substantial variation in climate consistent with the Greenland ice-core record. The exact correlation is hampered by temporal resolution, but the Finningley site stadial at approximately 40 ka may correlate with the one of the Greenland stadials 7–11.

scholarly journals Chapter 9 Peat hazards: compression and failure

2020 ◽  
Vol 29 (1) ◽  
pp. 243-257 ◽  
Author(s):  
Jeff Warburton
Keyword(s):  
Hydraulic Properties ◽  
Rheological Behaviour ◽  
Simple Relationship ◽  
Geological Hazards ◽  
Peat Soils ◽  
Geological Material ◽  
Considerable Uncertainty ◽  
Peat Deposits ◽  
Definition Of ◽  
The Uk

AbstractPeat is a highly compressible geological material whose time-dependent consolidation and rheological behaviour is determined by peat structure, degree of humification and hydraulic properties. This chapter reviews the engineering background to peat compression, describes the distribution of peat soils in the UK, provides examples of the hazards associated with compressible peat deposits and considers ways these hazards might be mitigated. Although some generalizations can be made about gross differences between broad peat types, no simple relationship exists between the magnitude and rate of compression of peat and loading. Based on examples described here, land failures resulting from peat compression are locally generated, but due to the sensitive nature of peat these can result in runaway failures that pose great risk. Understanding the geological hazards associated with compressible peat soils is challenging because peat is geotechnically highly variable and the mapped extent of peat in the UK is subject to considerable error due to inconsistencies in the definition of peat. Mitigating compression hazards in peat soils is therefore subject to considerable uncertainty; however, a combination of improved understanding of the properties of compressible peat, better mapping and land use zoning, and appropriate construction will help to mitigate risk.

Spring emergence of Eastern Box Turtles (Terrapene carolina): influences of individual variation and scale of temperature correlates

2017 ◽  
Vol 95 (1) ◽  
pp. 23-30 ◽  
Author(s):  
Brett A. DeGregorio ◽  
Tracey D. Tuberville ◽  
Robert A. Kennamer ◽  
Bess B. Harris ◽  
I. Lehr Brisbin
Keyword(s):  
Individual Variation ◽  
Meteorological Data ◽  
Terrapene Carolina ◽  
Air Temperatures ◽  
Winter Temperatures ◽  
Box Turtles ◽  
Eastern Box Turtles ◽  
Using Data ◽  
And Behavior ◽  
Spring Emergence

Many organisms spend considerable time in dormancy to avoid stressful environmental conditions. Understanding the timing and triggers of dormancy behavior is critical for understanding an animal’s life history and behavior. Eastern Box Turtles (Terrapene carolina (L., 1758)) avoid winter temperatures by burrowing into the soil and remaining dormant. Identifying the proximate environmental cues that trigger emergence can improve conservation efforts by reducing potential aboveground turtle mortality. During a 17-year study, half of all variation in emergence timing was attributed to individual variation and the habitat that they occupied during dormancy. We suggest that individual variation in emergence timing is common within populations and confounds efforts to identify reliable emergence cues. Additionally, the scale of meteorological data limits the ability to identify emergence predictors. Using data from temperature loggers placed at dormancy locations, we found that surface air temperatures, averaged over the 5 days prior to emergence, were more strongly related to emergence probability than any variables derived from local weather stations. Turtles generally did not emerge from dormancy until the 5-day mean surface temperatures measured at dormancy sites reached approximately 15 °C. Our results suggest that individuals respond differently to environmental thresholds for emergence and individuals may be characterized as risk-taking or risk-aversive.

Evaluating an interpolation approach for modelling spatial variability in pest development

2002 ◽  
Vol 92 (3) ◽  
pp. 219-231 ◽  
Author(s):  
C.H. Jarvis ◽  
R.H. Collier
Keyword(s):  
Spatial Variability ◽  
Input Data ◽  
Spline Interpolation ◽  
Local Variation ◽  
Estimation Methods ◽  
Horticultural Crops ◽  
Air Temperatures ◽  
Using Data ◽  
The One ◽  
The Uk

AbstractAir temperatures estimated by partial thin plate spline interpolation, or from the ‘nearest station’ (Voronoi polygon method), were used to model the phenology of three pests of horticultural crops throughout England and Wales. Temperatures for a particularly hot (1976) and a particularly cold (1986) year were interpolated to a grid resolution of 1 km. Estimates were made of the timing of spring emergence (Cecidophyopsis ribis (Westwood)), the maximum number of generations completed during the summer (Plutella xylostella (Linnaeus)) and the numbers of days when mating was possible (Merodon equestris (Fabricius)). The relative accuracy of the two temperature estimation methods was compared using jack-knife cross-validation. For C. ribis and P. xylostella, modelling with interpolated temperature input data was more accurate than using data from the ‘nearest station’. Of the three phenology models used, the one that relied on an activity threshold (M. equestris) was the most sensitive to both types of input data. Spatial variability in the activity of M. equestris adults was investigated in the two main areas (south-west peninsula and Lincolnshire) where its host crop (Narcissus) is grown. Modelling at cruder scales (up to 25*25 km) masked local variation, but the degree to which this was important varied from region to region and over time, as did the geography of the variability itself. The results indicate that interpolated data, computed to a resolution of 1 km using the UK synoptic network, have the potential for wider use within agricultural decision support systems for horticultural crops.

The Ethical Arguments Concerning the Artificial Ventilation of Patients With Motor Neurone Disease

1996 ◽  
Vol 3 (4) ◽  
pp. 317-328 ◽  
Author(s):  
Michele Anne Kent
Keyword(s):  
Caregiver Burden ◽  
Artificial Ventilation ◽  
Ethical Dilemmas ◽  
Informed Choice ◽  
Motor Neurone ◽  
Advanced Technology ◽  
Motor Neurone Disease ◽  
Accurate Data ◽  
First Order ◽  
The Uk

This paper focuses on the ethical dilemmas created by advanced technology that would allow patients with motor neurone disease to be sustained by artificial ventilation. The author attempts to support the patient's right to informed choice, arguing from the perspective of autonomy as a first order principle. The counter arguments of caregiver burden and financial restraints are analysed. In the UK, where active euthanasia is not legalized, the dilemma of commencing ventilation is seen to be outweighed by the problems of withdrawing this treatment. The lack of accurate data and protocols that would clarify the current situation is emphasized and the conclusion takes the form of a recommendation for further research.

scholarly journals 582 Maintenance of Fruiting Potential through the Winter for Merlot Grapevines Grown in Southwestern Michigan

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 496E-497
Author(s):  
Thomas J. Zabadal ◽  
Thomas Dittmer
Keyword(s):  
Air Temperature ◽  
Ambient Air ◽  
Annual Production ◽  
Market Opportunity ◽  
Wine Grape ◽  
Straw Mulch ◽  
Late Fall ◽  
Air Temperatures ◽  
Winter Temperatures ◽  
Cool Climate

Producing the cold-tender wine grape Merlot is a major challenge in the cool-climate viticultural region of southwestern Michigan. Merlot grapes produced in this region provide a strong market opportunity; therefore, several strategies for preserving the fruiting potential of vines through the winter were evaluated over 5 years. Vines were managed with frequent trunk renewal so that they were pliable and capable of being laid near the ground. One treatment was (A) a control. Three treatments involved pruning vines in the late fall to two to four canes, which were then (B) laid on the ground without any cover, (C) attached to a wire near the ground and covered with straw, or (D) attached to a wire near the ground and covered with 20 cm of soil. The fifth treatment (E) involved arching unpruned vines to place canes near the ground but without any covering. Pruning was completed in spring, and vines were tied using fan training. Vines were adjusted to a maximum of 40 live nodes per vine. Winter minimum temperatures averaged 1, 8 and 16 °C warmer than the air temperature at 1.5 m above ground when measured at 0.3 m above ground (B and E), under the straw mulch (C), and under the soil (D), respectively. Very low ambient air temperatures of –27 and –28 °C were experienced in two of the winter periods. C, D, and E consistently provided greater node survival through the winter than control vines. B was inconsistent in performance. The lowest annual yields for A through E for the 5-year period were 3.1, 0.7, 8.3, 6.7, and 9.0 tons per hectare, respectively. These data indicate that treatments C, D, and E were capable of reliable annual production of Merlot grapes even in years with episodes of low winter temperatures. Projects are under way to develop commercial capability for the vine burial and mulching techniques used in this study.

scholarly journals Microtopographic control on the ground thermal regime in ice wedge polygons

2018 ◽  
Author(s):  
Charles J. Abolt ◽  
Michael H. Young ◽  
Adam L. Atchley ◽  
Dylan R. Harp
Keyword(s):  
Rapid Change ◽  
Thermal Conditions ◽  
Ground Temperature ◽  
The Arctic ◽  
Near Surface ◽  
Hydrologic Processes ◽  
Ground Temperatures ◽  
Air Temperatures ◽  
Winter Temperatures ◽  
Ice Wedge

Abstract. The goal of this research is to constrain the influence of ice wedge polygon topography on near-surface ground temperatures. Because ice wedge polygon topography is prone to rapid change in a changing climate, and because cracking in the ice wedge depends on thermal conditions at the top of the permafrost, feedbacks between topography and ground temperature can shed light on the potential for future ice wedge cracking in the Arctic. We first report on a year of subdaily ground temperature observations at five depths and nine locations throughout a cluster of low-centered polygons near Prudhoe Bay, AK, and demonstrate that the rims become the coldest zone of the polygon during winter, due to thinner snowpack. We then calibrate a polygon-scale numerical model of coupled thermal and hydrologic processes against this dataset, achieving an RMSE of less than 1.2 °C between observed and simulated ground temperature. Finally, we conduct a sensitivity analysis of the model by systematically manipulating the height of the rims and the depth of the troughs, and tracking the effects on ice wedge temperature. The results indicate that deeper troughs lead to increased snow entrapment, promoting insulation of the ice wedge. Rims act as preferential outlets of subsurface heat; increasing rim size decreases winter temperatures in the ice wedge. The potential for ice wedge cracking is therefore reduced if rims are destroyed or if troughs subside, due to warmer conditions in the ice wedge. These findings can help explain the origins of secondary ice wedges in modern and ancient polygons. The findings also imply that the potential for reestablishing rims in modern thermokarst-affected terrain will be precluded by reduced cracking activity in the ice wedges, even if regional air temperatures stabilize.

Late Pleistocene climatic change in the French Jura (Gigny) recorded in the δ18O of phosphate from ungulate tooth enamel

2011 ◽  
Vol 75 (3) ◽  
pp. 605-613 ◽  
Author(s):  
Magali Fabre ◽  
Christophe Lécuyer ◽  
Jean-Philip Brugal ◽  
Romain Amiot ◽  
François Fourel ◽  
...  
Keyword(s):  
Oxygen Isotope ◽  
Cervus Elaphus ◽  
Red Deer ◽  
Tooth Enamel ◽  
Large Mammals ◽  
Air Temperatures ◽  
Winter Temperatures ◽  
French Jura ◽  
Summer Temperatures ◽  
Interdependent Relationships

AbstractOxygen isotope compositions of phosphate in tooth enamel from large mammals (i.e. horse and red deer) were measured to quantify past mean annual air temperatures and seasonal variations between 145 ka and 33 ka in eastern France. The method is based on interdependent relationships between the δ18O of apatite phosphate, environmental waters and air temperatures. Horse (Equus caballus germanicus) and red deer (Cervus elaphus) remains have δ18O values that range from 14.2‰ to 17.2‰, indicating mean air temperatures between 7°C and 13°C. Oxygen isotope time series obtained from two of the six horse teeth show a sinusoidal-like signal that could have been forced by temperature variations of seasonal origin. Intra-tooth oxygen isotope variations reveal that at 145 ka, winters were colder (− 7 ± 2°C) than at present (3 ± 1°C) while summer temperatures were similar. Winter temperatures mark a well-developed West–East thermal gradient in France of about − 9°C, much stronger than the −4°C difference recorded presently. Negative winter temperatures were likely responsible for the extent and duration of the snow cover, thus limiting the food resources available for large ungulates with repercussions for Neanderthal predators.

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