778 research outputs found
New frontiers in agricultural geography: transformations, food security, land grabs and climate change
Agriculture as a central focus of study featured prominently at several different times in the historical development of human geography, but it has also been an important contributor to the disciplinary transformation that has occurred since 1970. This essay outlines this more recent history, arguing that agricultural geography developed its own concepts and concerns, paralleling some of those within the wider discipline. It illustrates how in the past two decades attempts to examine changes occurring across the breadth of the agri-food system (from supply, to production, to consumption) have brought about a more issues-focused agricultural geography. There is discussion of the use of broad overarching concepts, which have conceived of changes to agriculture and the agri-food system in terms of episodic developments. This has seen recognition of different food regimes, acknowledging possible transitions from productivism to post-productivism to multifunctionality and perhaps neo-productivism. Having discussed these concepts, drawing extensively upon literature written in English, the essay then focuses on selected major problems or key issues to which agriciultural geographers are currently contributing new insights, namely the closely related topics of food security, land grabs and adaptations to climate change
Sporadic Human Cryptosporidiosis Caused by Cryptosporidium cuniculus, United Kingdom, 2007â2008
To investigate sporadic human cryptosporidiosis trends in the United Kingdom, we tested 3,030 Cryptosporidium spp.âpositive fecal samples, submitted for routine typing in 2007â2008, for C. cuniculus. C. cuniculus prevalence was 1.2%; cases were mostly indigenous and occurred across all age groups. Most occurred during AugustâOctober and may be linked to exposure opportunities
Direct sequencing of Cryptosporidium in stool samples for public health
The protozoan parasite Cryptosporidium is an important cause of diarrheal disease (cryptosporidiosis) in humans and animals, with significant morbidity and mortality especially in severely immunocompromised people and in young children in low-resource settings. Due to the sexual life cycle of the parasite, transmission is complex. There are no restrictions on sexual recombination between sub-populations, meaning that large-scale genetic recombination may occur within a host, potentially confounding epidemiological analysis. To clarify the relationships between infections in different hosts, it is first necessary to correctly identify species and genotypes, but these differentiations are not made by standard diagnostic tests and more sophisticated molecular methods have been developed. For instance, multilocus genotyping has been utilized to differentiate isolates within the major human pathogens, Cryptosporidium parvum and Cryptosporidium hominis. This has allowed mixed populations with multiple alleles to be identified: recombination events are considered to be the driving force of increased variation and the emergence of new subtypes. As yet, whole genome sequencing (WGS) is having limited impact on public health investigations, due in part to insufficient numbers of oocysts and purity of DNA derived from clinical samples. Moreover, because public health agencies have not prioritized parasites, validation has not been performed on user-friendly data analysis pipelines suitable for public health practitioners. Nonetheless, since the first whole genome assembly in 2004 there are now numerous genomes of human and animal-derived cryptosporidia publically available, spanning nine species. It has also been demonstrated that WGS from very low numbers of oocysts is possible, through the use of amplification procedures. These data and approaches are providing new insights into host-adapted infectivity, the presence and frequency of multiple sub-populations of Cryptosporidium spp. within single clinical samples, and transmission of infection. Analyses show that although whole genome sequences do indeed contain many alleles, they are invariably dominated by a single highly abundant allele. These insights are helping to better understand population structures within hosts, which will be important to develop novel prevention strategies in the fight against cryptosporidiosis
Improving landscape or recreating the picturesque?
Maintaining and restoring historic landscapes requires attention to native vegetation, cultural artefacts, historic buildings, hedges, stone walls and riparian woodland. One United Kingdom National Lottery scheme, which was launched in 1994, funds preservation of âheritage landscapesâ. This paper examines the Lotteryâs contribution to landscape restoration and rural development. It considers different scales at which restoration is occurring, focusing on three examples. The Leasowes estate is a small yet important example of a landscape garden in the eighteenth-century âpicturesqueâ taste. Croome Park, a National Trust property, boasts 270 hectares of parkland and a neo-Palladian mansion. The 105 sq km of the Malvern Hills is a human-created landscape traceable to prehistory, with landscape features dependent on longstanding grazing practices now threatened by changing farm economics. The article highlights different management approaches as it debates issues affecting landscape restoration and heritage management. Resolving tensions between official policy and cultural values within the community offer directions for further research.Au Royaume-Uni, le systĂšme de loterie du patrimoine finance la maintenance et la restauration des paysages patrimoniaux, en particulier la vĂ©gĂ©tation indigĂšne, les biens culturels, les bĂątiments historiques, les haies, les murs de pierre et les forĂȘts riveraines. Cet article Ă©tudie la contribution de ce type de financement Ă la restauration du paysage et au dĂ©veloppement rural. Il examine les diffĂ©rentes Ă©chelles de restauration Ă partir de trois exemples du centre de lâAngleterre : le domaine de âLeasowesâ, un petit jardin paysager dans le goĂ»t pittoresque du XVIIIe siĂšcle, âCroome Parkâ, une propriĂ©tĂ© du âNational Trustâ composĂ©e d'un parc de 270 ha et d'un manoir nĂ©o-palladien, et enfin âMalvern Hillsâ, une Ă©tendue de 105 km2 datant de la prĂ©histoire et dont les caractĂ©ristiques paysagĂšres dĂ©pendent de pratiques de pĂąturage ancestrales menacĂ©es par l'Ă©volution de l'Ă©conomie agricole. Lâarticle met en avant les diffĂ©rentes approches liĂ©es Ă la gestion du patrimoine ainsi que les problĂšmes associĂ©s Ă Â la restauration des paysages et Ă la gestion du patrimoine. La rĂ©solution des tensions entre les stratĂ©gies officielles et les valeurs culturelles au sein de la communautĂ© offre diverses orientations pour la poursuite de la recherche
Mumps and rubella surveillance in Victoria, 1993 to 2000
Despite improving childhood coverage of the measles-mumps-rubella vaccine (MMR) in Victoria during the 1990s, mumps and rubella notifications in age groups eligible for vaccination persisted. This study reviewed the mumps and rubella surveillance data from 1993 to 2000 with a specific focus on method of diagnosis. There were 474 notifications of mumps over the seven-year period (annual median 61, range 40 to 77) and 3,544 notifications of rubella (annual median 297, range 66 to 1,165). The highest notifications rates for mumps were consistently among the 1-4 and 5-9 year age groups, whereas there was a marked change in the age distribution of rubella notifications during this interval. A large rubella outbreak occurred in 1995 with 1,165 notifications; the highest notification rates were males aged 15-24 years, infants under one year of age (males and females), and those aged 5-14 years (males and females), respectively. The susceptibility of 5-24 year olds reflects historical changes to the Australian Standard Vaccination Schedule. Rubella notifications returned to baseline levels in 1998 with the highest notification rates in infants aged under one year, and children aged 1-4 years. For both mumps and rubella, the majority of notifications for all age groups were clinically diagnosed, and were most common in children. Commun Dis Intell 2003;27:94-99
Quantitation of the distribution and flux of myosin-II during cytokinesis
BACKGROUND: During cytokinesis, the cell's equator contracts against the cell's global stiffness. Identifying the biochemical basis for these mechanical parameters is essential for understanding how cells divide. To achieve this goal, the distribution and flux of the cell division machinery must be quantified. Here we report the first quantitative analysis of the distribution and flux of myosin-II, an essential element of the contractile ring. RESULTS: The fluxes of myosin-II in the furrow cortex, the polar cortex, and the cytoplasm were examined using ratio imaging of GFP fusion proteins expressed in Dictyostelium. The peak concentration of GFP-myosin-II in the furrow cortex is 1.8-fold higher than in the polar cortex and 2.0-fold higher than in the cytoplasm. The myosin-II in the furrow cortex, however, represents only 10% of the total cellular myosin-II. An estimate of the minimal amount of this motor needed to produce the required force for cell cleavage fits well with this 10% value. The cell may, therefore, regulate the amount of myosin-II sent to the furrow cortex in accordance with the amount needed there. Quantitation of the distribution and flux of a mutant myosin-II that is defective in phosphorylation-dependent thick filament disassembly confirms that heavy chain phosphorylation regulates normal recruitment to the furrow cortex. CONCLUSION: The analysis indicates that myosin-II flux through the cleavage furrow cortex is regulated by thick filament phosphorylation. Further, the amount of myosin-II observed in the furrow cortex is in close agreement with the amount predicted to be required from a simple theoretical analysis
Exploring âpro-environmentalâ actions through discarded materials in the home
The household is a crucial focus of both waste and wider environmental policy, being seen as a central site of socio -economic-environmental change, a space in which people may perform their civic responsibilities and where individual and wider imperatives are brought together. Yet policy makers have shown limited appreciation and understanding of what happens inside the home. So in contemporary waste policy, for example, households remain a âclosed entityâ in which everyday routines and practices remain hidden. Increasingly, though, it is acknowledged by social scientists that the lived experiences of environmental and waste management in the home are significant issues requiring further study, but how we might go about trying to study them is proving a challenging question. Conventional pro-environmental behaviour research has often tended to study behaviours in ways abstracted from the social contexts in which these take place. This has prompted recent research involving repeat in-depth interviews with householders and more ethnographic approaches, the use of reflexive diaries and narrative methodologies. Curiously, however, there has been little research considering environmental management(s) in the home which has focussed on waste itself. This paper seeks to add to the discussion, by focusing on everyday processes within households, using a qualitative approach of âgetting in the binâ of households - that is, an interview approach which takes respondentsâ discarded waste as a starting point from which we ask them to discuss the lived experience(s) and activities of everyday life. More broadly by developing insights from what has been termed a ârealist governmentalityâ perspective the paper seeks to offer a more nuanced and finely grained analysis of governing in situ, exploring the extent to which governmental ambitions in relation to waste are accommodated, resisted or [re]worked at the household level. The paper draws illustratively on case studies from a Leverhulme-funded research project based in Kingston-Upon-Thames, an outer London borough in the UK. The approach used a focus on the contents of household waste bins to develop a narrative approach driven by householders centred on stories about pro-environmental practice. The paper will deal with three elements of the research approach: texturing narratives of waste, generating narratives of recycling in practice, and producing narratives of understanding. The outcome is development of a more thoroughgoing understanding of how processes within the home shape waste governance, moving beyond treating the home as a closed entity
Can Famine Be Averted? A Spatiotemporal Assessment of The Impact of Climate Change on Food Security in The Luvuvhu River Catchment of South Africa
Climate change has proved to be a threat to food security the world over. Using temperature and precipitation data, this paper examines the differential effects climate change has on different land uses in the Luvuvhu river catchment in South Africa. The paper uses the Normalised Difference Vegetation Index (NDVI) and Vegetation Condition Index (VCI), which were calculated from Landsat images, and the Standardised Precipitation Index (SPI) for a sample of years between 1980 and 2016 to assess how drought and flood frequency have affected the agricultural environment. The results indicate that the lowest SPI values were recorded in 1996/1997, 2001/2002 and 2014/2015, suggesting the occurrence of drought during these years, while the highest SPI values were recorded in 1997/1998, 2002/2003 and 2004/2005. The relationship between three-month SPI (SPI_3) and VCI was strongest in grassland, and subsistence farming areas with the correlation coefficients of 0.8166 (p = 0.0022) and â0.6172 (p = 0.0431), respectively, indicating that rainfall variability had a high negative impact on vegetation health in those land uses with shallow-rooted plants. The findings of this study are relevant to disaster management planning in South Africa, as well as development of farming response strategies for coping with climate hazards in the country.</jats:p
Analysis of the Cryptosporidium spp. and gp60 subtypes linked to human outbreaks of cryptosporidiosis in England and Wales, 2009 to 2017
Abstract Background Cryptosporidium spp. are important causes of gastroenteritis that can be transmitted from humans and animals. We elucidated the distribution of species and gp60 subtypes in human outbreaks classified by transmission vehicle. Methods We used a combined database of national outbreak surveillance and reference unit data to analyse outbreaks by setting, vehicle, season, and linkage with suspected sources. Results A total of 178 outbreaks involving 4031 laboratory confirmed cases were identified; 82 (46%) outbreaks involved recreational waters, 74 (42%) animal contact, 4 (2%) environmental contact, 4 (2%) person-to-person spread, 3 (2%) food, 2 (1%) drinking water supplies, and 9 (5%) were of unknown source. The infecting Cryptosporidium sp. was identified in 131 (74%) outbreaks; 69 were C. parvum, 60 C. hominis, and in two outbreaks cases were infected with either species. Animal contact, environmental contact, and food-borne outbreaks were exclusively C. parvum and were mainly in first half of the year. Recreational water outbreaks were predominantly C. hominis and were mainly in the second half of the year. Outbreaks attributed to person-to-person spread were exclusively C. hominis and all occurred in October. Both C. parvum and C. hominis caused drinking waterborne outbreaks. Gp60 subtypes were identified from patients in 48 C. parvum and 38 C. hominis outbreaks, revealing more subtypes among C. parvum (nâ=â14) than C. hominis (nâ=â7) outbreaks. Cryptosporidium hominis IbA10G2 predominated (30 outbreaks). Of C. parvum subtypes, IIaA15G2R1 predominated (17 outbreaks), followed by IIaA17G1R1 (12 outbreaks), IIaA19G1R1 (four outbreaks), and other subtypes caused three or fewer outbreaks each. Linkage between cases and suspected sources by gp60 subtype was established in nine animal contact, three swimming pool, and one drinking water outbreak. Conclusions The public health benefit of identifying infecting species and subtypes was twofold: (i) identifying and strengthening epidemiologic links between cases; and (ii) indicating possible exposures and sources to inform outbreak management. Gp60 subtype refined the epidemiological investigations, but a multilocus genotyping scheme would provide further benefit. Characterisation of Cryptosporidium spp. and subtypes needs to shift from predominantly supporting outbreak investigations to becoming nationally systematic
Detection and molecular characterisation of Cryptosporidium parvum in British European hedgehogs (Erinaceus europaeus)
Surveillance was conducted for the occurrence of protozoan parasites of the genus Cryptosporidium in European hedgehogs (Erinaceus europaeus) in Great Britain. In total, 108 voided faecal samples were collected from hedgehogs newly admitted to eight wildlife casualty treatment and rehabilitation centres. Terminal large intestinal (LI) contents from three hedgehog carcasses were also analysed. Information on host and location variables, including faecal appearance, body weight, and apparent health status, was compiled. Polymerase Chain Reaction (PCR) targeting the 18S ribosomal RNA gene, confirmed by sequencing, revealed an 8% (9/111) occurrence of Cryptosporidium parvum in faeces or LI contents, with no significant association between the host or location variables and infection. Archived small intestinal (SI) tissue from a hedgehog with histological evidence of cryptosporidiosis was also positive for C. parvum by PCR and sequence analysis of the 18S rRNA gene. No other Cryptosporidium species were detected. PCR and sequencing of the glycoprotein 60 gene identified three known zoonotic C. parvum subtypes not previously found in hedgehogs: IIdA17G1 (n=4), IIdA19G1 (n=1) and IIdA24G1 (n=1). These subtypes are also known to infect livestock. Another faecal sample contained C. parvum IIcA5G3j which has been found previously in hedgehogs, and for which there is one published report in a human, but is not known to affect livestock. The presence of zoonotic subtypes of C. parvum in British hedgehogs highlights a potential public health concern. Further research is needed to better understand the epidemiology and potential impacts of Cryptosporidium infection in hedgehogs
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