12 results on '"Ashpole I"'
Search Results
2. Plumes and blooms - Locally-sourced Fe-rich aeolian mineral dust drives phytoplankton growth off southwest Africa
- Author
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Dansie, AP, Thomas, DSG, Wiggs, GFS, Baddock, MC, and Ashpole, I
- Subjects
Minerals ,Environmental Engineering ,Iron ,Oceans and Seas ,Phytoplankton ,Environmental Chemistry ,Dust ,Pollution ,Waste Management and Disposal ,Namibia - Abstract
Ocean-based photosynthesis accounts for half of global primary production. Productivity rates, driven by phytoplanktonic responses to nutrient availability, are however highly variable both spatially and temporally throughout the oceans. Intense primary production in the ocean's most productive areas, the Eastern Boundary Upwelling Systems (EBUS), cannot be fully explained by nutrient upwelling alone, with the role of local dust sources and complimentary aeolian nutrient delivery largely overlooked. Here we explore relationships between iron-rich dust plumes emanating from a significant regional dust source, Namibia's ephemeral river valleys, and blooms of phytoplankton growth off southwest Africa in the Benguela Upwelling System (BUS). We constrain dust source dynamics through field measurement of in-valley airborne dust concentrations made at daily resolution, and couple these with satellite observations of atmospheric aerosols, ocean phytoplankton concentrations, and sea surface temperature over a six-month period encompassing the known ‘dust season’ of the valley sources. Phytoplanktonic responses in BUS waters to individual dust emission events were identified and were importantly shown to be unassociated with upwelling events. We demonstrate a fast (1–2 day) chlorophyllic response to observed iron-rich dust emissions, a relationship that is concealed by monthly averaged data. We show that terrestrial in-valley airborne dust concentrations correlate with offshore increases in phytoplankton concentrations, providing the first study of oceanic response that is directly linked with a specific monitored terrestrial dust source.
- Published
- 2021
3. Fatal Outbreak of Toxoplasmosis in Captive Pallas’s Cats (Otocolobus manul)
- Author
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Costa, T., primary, Ashpole, I., additional, and Chantrey, J., additional
- Published
- 2020
- Full Text
- View/download PDF
4. Patterns and causes of spatial and temporal variability of dust presence in the central and western Sahara
- Author
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Ashpole, I and Washington, R
- Subjects
Atmospheric chemistry ,Geography ,Africa ,Atmospheric,Oceanic,and Planetary physics ,Climate systems and policy ,Arid environmental systems - Abstract
Dust is a critical component of the Earth System. The central and western Sahara (CWS) is the dustiest place on Earth during the northern hemisphere summer. Understanding patterns and causes of spatial and temporal variability of dust presence here is essential for its reliable simulation in numerical models of weather and climate. Four papers in this thesis contribute to that objective, utilising a combination of high temporal resolution satellite data and global atmospheric reanalyses for June – August 2004 – 2010 inclusive. The first paper develops an objective dust detection scheme for the CWS using data from the Spinning Enhanced Visible and Infrared Imager (SEVIRI), which are available every 15 minutes around the clock. These data have shed valuable insight on CWS dust processes, but their subjective application has to date limited their range of applications. The SEVIRI dust flag (SDF) developed here is evaluated against other widely used surface and satellite derived indicators of dustiness and it is found to reliably detect the presence of moderate-heavy dust loadings. The distribution of dust each summer is presented, revealing a high degree of interannual variability in overall dust coverage. The second paper utilises SDF to create an objective, high spatial resolution dust source map, based on the automated tracking of individual dust plumes. The most active sources are associated predominantly with palaeo-lakes and outwash plains, typically around the Saharan mountains. There is a clear intraseasonal progression of active source areas, controlled by regional climatology. The tracking scheme describes the transport trajectory of dust events following their initiation and the spatial association with deep convection at this time, revealing a clear regional divide in the relative importance of known meteorological mechanisms that drive dust emission from the dominant sources. The third paper uses an unsupervised clustering algorithm to classify maps of daily dust presence frequency and identify patterns of intraseasonal variability in CWS dust coverage. The resulting idealised dust states vary according to frequency of dust occurrence and its location, demonstrating a clear progression in preferred dust location from June – August and preferred state transitions from one day to the next. High daily dust occurrence frequency corresponds to an advanced West African Monsoon flow and low daily dust occurrence frequency corresponds to a Harmattan-dominated CWS. The overall location of the dust is linked to the location of the Sahara Heat Low, which changes as the summer progresses. The final paper addresses interannual variability in summertime dust presence frequency by comparing the 2 years with highest (2005) and lowest (2008) dust presence. The key difference is the occurrence of 3 multi-day periods in 2005 characterised by anomalously high dust presence. Case study comparison with the 3 periods of highest dust presence in 2008 identifies the anticyclonic circulation of the midtroposphere as a key control on dust duration over the CWS, dictating whether emitted dust is efficiently transported away from the CWS or whether it remains in suspension over the region for prolonged periods of time, up to several days in the anomalously dusty periods of 2005.
- Published
- 2016
5. The role of human influence on climate in recent UK winter floods and their impacts
- Author
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Schaller, N, Weisheimer, A, Kay, AL, Massey, NR, van Oldenborgh, GJ, Otto, FEL, Sparrow, SN, Vautard, R, Yiou, P, Ashpole, I, Bowery, A, Crooks, SM, Haustein, K, Huntingford, C, Ingram, WJ, Jones, RG, Legg, T, Miller, J, Skeggs, J, Wallom, D, Wilson, S, Stott, PA, and Allen, MR
- Abstract
A succession of storms reaching southern England in the winter of 2013/2014 caused severe floods and £451 million insured losses. In a large ensemble of climate model simulations, we find that, as well as increasing the amount of moisture the atmosphere can hold, anthropogenic warming caused a small but significant increase in the number of January days with westerly flow, both of which increased extreme precipitation. Hydrological modelling indicates this increased extreme 30-day-average Thames river flows, and slightly increased daily peak flows, consistent with the understanding of the catchment’s sensitivity to longer-duration precipitation and changes in the role of snowmelt. Consequently, flood risk mapping shows a small increase in properties in the Thames catchment potentially at risk of riverine flooding, with a substantial range of uncertainty, demonstrating the importance of explicit modelling of impacts and relatively subtle changes in weather-related risks when quantifying present-day effects of human influence on climate.
- Published
- 2016
6. A critical evaluation of the ability of the Spinning Enhanced Visible and Infrared Imager (SEVIRI) thermal infrared red-green-blue rendering to identify dust events: Theoretical analysis
- Author
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Brindley, H., Knippertz, P., Ryder, Claire, and Ashpole, I.
- Abstract
Using a combination of idealized radiative transfer simulations and a case study from the first field campaign of the Saharan Mineral Dust Experiment (SAMUM) in southern Morocco, this paper provides a systematic assessment of the limitations of the widely used Spinning Enhanced Visible and Infrared Imager (SEVIRI) red-green-blue (RGB) thermal infrared dust product. Both analyses indicate that the ability of the product to identify dust, via its characteristic pink coloring, is strongly dependent on the column water vapor, the lower tropospheric lapse rate, and dust altitude. In particular, when column water vapor exceeds ∼20–25 mm, dust presence, even for visible optical depths of the order 0.8, is effectively masked. Variability in dust optical properties also has a marked impact on the imagery, primarily as a result of variability in dust composition. There is a moderate sensitivity to the satellite viewing geometry, particularly in moist conditions. The underlying surface can act to confound the signal seen through variations in spectral emissivity, which are predominantly manifested in the 8.7μm SEVIRI channel. In addition, if a temperature inversion is present, typical of early morning conditions over the Sahara and Sahel, an increased dust loading can actually reduce the pink coloring of the RGB image compared to pristine conditions. Attempts to match specific SEVIRI observations to simulations using SAMUM measurements are challenging because of high uncertainties in surface skin temperature and emissivity. Recommendations concerning the use and interpretation of the SEVIRI RGB imagery are provided on the basis of these findings.
- Published
- 2012
7. HISTOPATHOLOGIC FINDINGS IN 10 CASES OF MORTALITY IN CAPTIVE MALAYSIAN FIRE SNAILS ( PLATYMMA TWEEDIEI ).
- Author
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Richards-Rios P, Ashpole I, Chantrey J, and Barbon AR
- Subjects
- Animals, Female, Male, Animals, Zoo, Snails parasitology
- Abstract
Malaysian fire snails (Platymma tweediei) , face threats to their environment, including habitat destruction and the illegal wildlife trade. Captive breeding projects are likely to play a role in the survival of this species; however, mortality in captive populations potentially presents a significant challenge. This paper presents the results of histopathologic examination of tissues from 10 P. tweediei casualties in a captive population at Chester Zoo. In October 2022, a captive breeding program was established with 20 wild-born P. tweediei . All adult founder animals died by July 2023, of which 10 were submitted for necropsy and histopathology of organs. Significant histologic abnormalities were present in all cases, primarily affecting the lung, integument, and heart. Histological analyses indicated a pneumonia-like condition was prevalent in all cases, suggesting potential environmental factors contributed to respiratory infections. A variety of possible etiologic or secondary infectious agents were present in sections including bacteria, fungi, and trematodes. There were some challenges in interpreting the histologic changes, emphasizing the need for more reference material and studies on the normal histologic anatomy of terrestrial gastropods. The findings underline the importance of understanding mortality events in captive populations to improve husbandry and environmental management. Additionally, the study recommends the submission of fresh specimens for necropsy to enhance diagnostic capabilities, such as bacterial culture, and suggests targeted sampling strategies for future research on captive snail species.
- Published
- 2024
- Full Text
- View/download PDF
8. Cowpox in zoo and wild animals in the United Kingdom.
- Author
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Costa T, Stidworthy MF, Ehmann R, Denk D, Ashpole I, Drake G, Maciuca I, Zoeller G, Meyer H, and Chantrey J
- Subjects
- Humans, Animals, Animals, Wild, Retrospective Studies, Vermilingua, Cowpox virus, United Kingdom epidemiology, Animals, Zoo, Cowpox epidemiology, Cowpox veterinary, Otters, Tigers, Panthera, Deer
- Abstract
Cowpox virus is considered to be a re-emerging zoonotic pathogen and a public health threat due to increasing numbers of cases in humans and animals in Europe over the past decade, including within the United Kingdom (UK). We present epidemiological data and diagnostic features of 27 recent, naturally occurring cowpox cases in zoo and wild animals across the UK, including the first reports of cowpox in two snow leopards (Panthera uncia), a Bengal tiger (Panthera tigris tigris), three Chilean pudus (Pudu puda), a Malayan tapir (Tapirus indicus) and a Eurasian otter (Lutra lutra), and the first reports of Orthopoxvirus infection in a lar gibbon (Hylobates lar), a Southern tamandua (Tamandua tetradactyla) and an aardvark (Orycteropus afer). This study provides a detailed overview of cowpox infections in a wide range of non-domestic animal species, presents a range of methods for diagnosis and demonstrates the value of retrospective analysis of pathology surveillance in revealing epidemiological links., (Copyright © 2023 University of Liverpool, UK. Published by Elsevier Ltd.. All rights reserved.)
- Published
- 2023
- Full Text
- View/download PDF
9. Nectarivorous Bird Emphysematous Ingluvitis (NBEI): A Novel Disease in Loriinae Birds Associated With Clostridium perfringens Infection.
- Author
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Rich AF, Zendri F, Costa T, Timofte D, Drake GJ, Rowland H, Ashpole I, Moore A, and Chantrey J
- Abstract
A retrospective study revealed ten cases of emphysematous ingluvitis in Loriinae birds from two zoological collections between 2009 and 2020. Common clinical features were sudden death with gas distention of the crop, subcutaneous cervical emphysema and poor body condition, but also included collapse, hypothermia and abandonment. Macroscopic examination revealed moderate crop enlargement, distention and thickening with minimal intraluminal content, and moderate to severe submucosal to transmural gas-filled cysts (emphysema). Histopathology identified widespread transmural multifocal to coalescing empty pseudo-cystic cavities with lytic necrosis, pyo-/granulomatous inflammatory infiltrates, epithelial ulceration, parakeratotic hyperkeratosis, epithelial ballooning degeneration, and occasional intralesional rod-shaped bacteria. The lesion may have impaired the birds' ability to ingest food, resulting in suboptimal body condition. Necrotizing to granulomatous aspiration pneumonia was also a feature in some cases. Anaerobic bacterial culture of four crops identified Clostridium perfringens with associated toxin genes for alpha and occasionally beta2 toxin ( cpa and cpb2 genes respectively), by PCR analysis of bacterial isolates cultured from fresh or frozen tissue. C. perfringens was identified as the common etiological agent of emphysematous ingluvitis in crop and/or liver (six out of ten birds), and type A was confirmed in five birds. C. perfringens was not detected in the crop nor liver of two unaffected Loriinae birds. This is the first publication that characterizes nectarivorous bird emphysematous ingluvitis (NBEI), attributes C. perfringens as an etiological agent, and highlights this novel disease as an important cause of death in Loriinae birds, particularly in nestling and fledgling stage of development, but also in older lorikeets and lories., (Copyright © 2020 Rich, Zendri, Costa, Timofte, Drake, Rowland, Ashpole, Moore and Chantrey.)
- Published
- 2020
- Full Text
- View/download PDF
10. Retrieval of the Complete Coding Sequence of the UK-Endemic Tatenale Orthohantavirus Reveals Extensive Strain Variation and Supports Its Classification as a Novel Species.
- Author
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Chappell JG, Tsoleridis T, Onianwa O, Drake G, Ashpole I, Dobbs P, Edema W, Kumi-Ansah F, Bennett M, Tarlinton RE, Ball JK, and McClure CP
- Subjects
- High-Throughput Nucleotide Sequencing, RNA, Viral, Sequence Analysis, RNA, United Kingdom, Genetic Variation, Orthohantavirus classification, Orthohantavirus genetics, Open Reading Frames, Phylogeny
- Abstract
Orthohantaviruses are globally distributed viruses, associated with rodents and other small mammals. However, data on the circulation of orthohantaviruses within the UK, particularly the UK-endemic Tatenale virus, is sparse. In this study, 531 animals from five rodent species were collected from two locations in northern and central England and screened using a degenerate, pan- orthohantavirus RT-PCR assay. Tatenale virus was detected in a single field vole ( Microtus agrestis ) from central England and twelve field voles from northern England. Unbiased high-throughput sequencing of the central English strain resulted in the recovery of the complete coding sequence of a novel strain of Tatenale virus, whilst PCR-primer walking of the northern English strain recovered almost complete coding sequence of a previously identified strain. These findings represented the detection of a third lineage of Tatenale virus in the United Kingdom and extended the known geographic distribution of these viruses from northern to central England. Furthermore, the recovery of the complete coding sequence revealed that Tatenale virus was sufficiently related to the recently identified Traemersee virus, to meet the accepted criteria for classification as a single species of orthohantavirus.
- Published
- 2020
- Full Text
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11. Characterization of Livestock-Associated Methicillin-Resistant Staphylococcus aureus CC398 and mecC-positive CC130 from Zoo Animals in the United Kingdom.
- Author
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Bortolami A, Verin R, Chantrey J, Corrò M, Ashpole I, Lopez J, and Timofte D
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- Animals, Animals, Zoo, Anti-Bacterial Agents pharmacology, Cefoxitin pharmacology, Clone Cells, Female, Gene Expression, Genotype, Male, Methicillin Resistance genetics, Methicillin-Resistant Staphylococcus aureus drug effects, Methicillin-Resistant Staphylococcus aureus isolation & purification, Microbial Sensitivity Tests, Multilocus Sequence Typing, Staphylococcal Infections epidemiology, Staphylococcal Infections microbiology, Staphylococcal Infections pathology, United Kingdom epidemiology, Virulence Factors metabolism, Genes, Bacterial, Herpestidae microbiology, Methicillin-Resistant Staphylococcus aureus genetics, Methicillin-Resistant Staphylococcus aureus pathogenicity, Staphylococcal Infections veterinary, Virulence Factors genetics
- Abstract
Little is known about the characteristics and diseases associated with methicillin-resistant Staphylococcus aureus (MRSA) in nondomestic animals. Four presumptive MRSA isolates, obtained from clinical (n = 3) and surveillance specimens (n = 1) from dwarf (Helogale parvula) and yellow mongooses (Cynictis penicillata) from a United Kingdom zoo, were analyzed by PCR for detection of mecA and mecC-mediated methicillin resistance, and virulence genes. Isolates were genotyped by multilocus sequence typing (MLST) and staphylococcal cassette chromosome mec (SCCmec) and spa sequence typing. Three isolates, obtained from the dwarf mongooses, carried mecA, tetK, and fexA resistance and virulence genes (icaA, icaD, and sec) and were typed to SCCmec IVa, spa type t899, and clonal complex (CC) 398. The fourth MRSA isolate, obtained from the femoral bone marrow of a yellow mongoose showing postmortem findings consistent with septicemia, carried mecC and was oxacillin/cefoxitin susceptible, when tested at 37°C but showed a characteristic MRSA susceptibility profile at 25°C ± 2°C. Furthermore, this isolate exhibited a different genetic background (SCCmecXI/t843/CC130) and had biofilm-associated genes (bap, icaA, and icaD) and tetK tetracycline resistance genes. This work describes the first isolation of livestock-associated MRSA CC398 from two zoo mongoose species where it was associated with both clinical disease and colonization, and the first isolation of mecC MRSA from a zoo species in the United Kingdom. Both reports highlight the potential for zoo species to act as reservoirs for these zoonotic agents.
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- 2017
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12. Dust as a tipping element: the Bodele Depression, Chad.
- Author
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Washington R, Bouet C, Cautenet G, Mackenzie E, Ashpole I, Engelstaedter S, Lizcano G, Henderson GM, Schepanski K, and Tegen I
- Abstract
Dust plays a vital role in climate and biophysical feedbacks in the Earth system. One source of dust, the Bodélé Depression in Chad, is estimated to produce about half the mineral aerosols emitted from the Sahara, which is the world's largest source. By using a variety of new remote sensing data, regional modeling, trajectory models, chemical analyses of dust, and future climate simulations, we investigate the current and past sensitivity of the Bodélé. We show that minor adjustments to small features of the atmospheric circulation, such as the Bodélé Low-Level Jet, could profoundly alter the behavior of this feature. Dust production during the mid-Holocene ceased completely from this key source region. Although subject to a great deal of uncertainty, some simulations of the 21st century indicate the potential for a substantial increase in dust production by the end of the century in comparison with current values.
- Published
- 2009
- Full Text
- View/download PDF
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