123 research outputs found

    Investigating the conservation value of leopard population indices obtained through camera traps in the greater Kruger region of South Africa

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    Leopards (Panthera pardus) are one of the most widespread large felids, historically ranging across much of Africa, the middle east and Asia. Their solitary and elusive nature has allowed them to persist in many areas where other members of the large carnivore guild have been extirpated. However, the combined effects of habitat loss, reduced prey abundance, unsustainable trophy hunting, negative interactions with humans and a growing demand for body parts are taking their toll on the species. Leopards now occupy between 25 and 37% of their historic range, and population densities are decreasing across many small reserves in South Africa. Modifications to current management regimes, informed by monitoring programs, are thus crucial to the persistence of the species. Kruger National Park (KNP) is the largest protected area in South Africa and has thus been assumed to be an inviolate refuge for leopards, despite a lack of data on key leopard population parameters. In this thesisI provide crucial density estimates for leopardsin different regions of KNP and adjacent privately managed areas. Additionally, I explore other often neglected data routinely recorded by camera traps that are potentially important to refining population monitoring efforts. Specifically, I investigate temporal leopard activity quantified using time stamps on photographs of individuals and the potential drivers of activity patterns across differentsites as well asthe relationship between phenotypic similarity derived from photographs of known individuals and relatedness estimates from pedigree data. Multisession spatial capture-recapture (SCR) models proved useful in estimating density across sites and looking at drivers of density. Leopard density ranged from 2.6 Ā± 0.6 to 13.2 Ā± 2.6 leopards/100km2 across the sites surveyed. Differences in reserve management appear to be having a substantial effect on the density of leopard populations, providing cause for concern that leopards are being negatively affected by anthropogenically driven mortalities and populations are thus failing to reach their carrying capacity. Normalised Difference Vegetation Index (NDVI) was also an important driver of density, showing a strong interaction with Reserve Type. Higher NDVI was more strongly positively correlated with leopard density in better protected reserves. Leopard activity was predominantly nocturnal with crepuscular peaks and diel activity patterns that differed between sites. These differences were driven mainly by seasonal variation in temperatures and not the relative abundance of humans, potential competitors, or prey. Leopard activity also varied on a lunar scale, with leopards showing higher activity levels with greater lunar illumination, possibly in response to decreased hunting success at higher light levels. I quantified phenotypic similarity in leopards from the Sabi Sand Game Reserve (SSGR) by measuring the resemblance of flank rosette patterns using Hotspotter and ImageJ software and manually recording the resemblance of whisker spot markings. I then compared these metrics to relatedness scores obtained from a pedigree derived from known maternal relationships with offspring. Despite six of 15 phenotypic metrics showing significant heritability, this relationship was noisy at the population level and thus phenotypic resemblance measures derived from photographic data could not provide information on the level of relatedness between leopard individuals from within populations. The data collected throughout this study provides a comprehensive baseline of leopard population status in KNP and select adjacent and contiguous private protected areas. Density remains highest in the SSGR which invests heavily in preventing negative anthropogenic impacts, is intermediate in KNP where there is concern over the potential for some human induced mortality and is lowest in Karingani Game Reserve (KGR), a protected area in its infancy where the effects of protection have not yet had time to materialise. This study also provides an indication of the uses and limitations of camera trap data, and how it can be helpful in informing leopard conservation and management

    Initial development and testing of a novel foam-based pressure sensor for wearable sensing

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    BACKGROUND: This paper provides an overview of initial research conducted in the development of pressure-sensitive foam and its application in wearable sensing. The foam sensor is composed of polypyrrole-coated polyurethane foam, which exhibits a piezo-resistive reaction when exposed to electrical current. The use of this polymer-coated foam is attractive for wearable sensing due to the sensor's retention of desirable mechanical properties similar to those exhibited by textile structures. METHODS: The development of the foam sensor is described, as well as the development of a prototype sensing garment with sensors in several areas on the torso to measure breathing, shoulder movement, neck movement, and scapula pressure. Sensor properties were characterized, and data from pilot tests was examined visually. RESULTS: The foam exhibits a positive linear conductance response to increased pressure. Torso tests show that it responds in a predictable and measurable manner to breathing, shoulder movement, neck movement, and scapula pressure. CONCLUSION: The polypyrrole foam shows considerable promise as a sensor for medical, wearable, and ubiquitous computing applications. Further investigation of the foam's consistency of response, durability over time, and specificity of response is necessary

    Immediate replacement of fishing with dairying by the earliest farmers of the NE Atlantic archipelagos

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    The appearance of farming, from its inception in the Near East around 12 000 years ago, finally reached the northwestern extremes of Europe by the fourth millennium BC or shortly thereafter. Various models have been invoked to explain the Neolithization of northern Europe; however, resolving these different scenarios has proved problematic due to poor faunal preservation and the lack of specificity achievable for commonly applied proxies. Here, we present new multi-proxy evidence, which qualitatively and quantitatively maps subsistence change in the northeast Atlantic archipelagos from the Late Mesolithic into the Neolithic and beyond. A model involving significant retention of hunterā€“gathererā€“fisher influences was tested against one of the dominant adoptions of farming using a novel suite of lipid biomarkers, including dihydroxy fatty acids, Ļ‰-(o-alkylphenyl)alkanoic acids and stable carbon isotope signatures of individual fatty acids preserved in cooking vessels. These new findings, together with archaeozoological and human skeletal collagen bulk stable carbon isotope proxies, unequivocally confirm rejection of marine resources by early farmers coinciding with the adoption of intensive dairy farming. This pattern of Neolithization contrasts markedly to that occurring contemporaneously in the Baltic, suggesting that geographically distinct ecological and cultural influences dictated the evolution of subsistence practices at this critical phase of European prehistory

    T lymphocyte insensitivity to corticosteroids in chronic obstructive pulmonary disease

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    <p>Abstract</p> <p>Background</p> <p>There are increased numbers of activated lymphocytes in the lungs of chronic obstructive pulmonary disease (COPD) patients. The clinical benefits of corticosteroids in COPD patients are limited. Our hypothesis is that lymphocytes play a role in this corticosteroid insensitivity.</p> <p>Objectives</p> <p>To investigate the effects of the corticosteroid dexamethasone on lung lymphocyte cytokine production from patients with COPD compared to controls.</p> <p>Methods</p> <p>Cultured airway lymphocytes obtained by bronchoscopy from healthy non-smokers (HNS), smokers (S) and COPD patients were stimulated with phytohaemagglutinin (PHA) & phorbol myristate acetate (PMA), +/- dexamethasone. Supernatants were assayed for interleukin (IL)-2 and interferon (IFN)Ī³. Immunofluoresence was used to analyse changes in CD8 glucocorticoid receptor (GRĪ± and GRĪ²) expression.</p> <p>Results</p> <p>The inhibition of PHA/PMA stimulated IFNĪ³ production by dexamethasone was reduced in COPD patients compared to HNS (<it>p </it>< 0.05 at concentrations from 0.1-1 Ī¼M). There was also a significant reduction (<it>p </it>< 0.05) in the mean inhibitory effect at 1 Ī¼M in COPD patients (54.1%) compared to smokers (72.1%), and in smokers compared to HNS (85.5%). There was a numerically reduced effect of dexamethasone on IL-2 production that did not reach statistical significance. There was no difference in GRĪ± and GRĪ² expression in follicular CD8 cells between COPD patients (50.9% and 30.4% respectively) and smokers (52.9% and 29.7% respectively).</p> <p>Conclusions</p> <p>IFNĪ³ production from COPD airway lymphocytes is corticosteroid insensitive. This phenomenon may be important in the poor clinical response often observed with corticosteroids.</p

    Improved quantification of HIV-1 infected CD4 + T cells using an optimised method of intracellular HIV-1 gag p24 antigen detection

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    The capacity of CD8+ T cells to inhibit HIV-1 replication in vitro strongly correlates with virus control in vivo. Post-hoc evaluations of HIV-1 vaccine candidates suggest that this immunological parameter is a promising benchmark of vaccine efficacy. Large-scale analysis of CD8+ T cell antiviral activity requires a rapid, robust and economical assay for accurate quantification of HIV-1 infection in primary CD4+ T cells. Detection of intracellular HIV-1 p24 antigen (p24 Ag) by flow cytometry is one such method but it is thought to be less sensitive and quantitative than p24 Ag ELISA. We report that fixation and permeabilisation of HIV-infected cells using paraformaldehyde/50% methanol/Nonidet P-40 instead of a conventional paraformaldehyde/saponin-based protocol improved their detection across multiplicities of infection (MOI) ranging from 10-2 to 8Ɨ10-5, and by nearly two-fold (p&lt;0.001) at the optimal MOI tested (10-2). The frequency of infected cells was strongly correlated with p24 Ag release during culture, thus validating its use as a measure of productive infection. We were also able to quantify infection with a panel of HIV-1 isolates representing the major clades. The protocol described here is rapid and cost-effective compared with ELISA and thus could be a useful component of immune monitoring of HIV-1 vaccines and interventions to reduce viral reservoirs. Ā© 2013 Elsevier B.V

    Constitutive expression of the anti-apoptotic Bcl-2 family member A1 in murine endothelial cells leads to transplant tolerance

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    Anti-apoptotic genes including those of the Bcl-2 family have been shown to have dual functionality in as much as they inhibit cell death but also regulate inflammation. Several anti-apoptotic molecules have been associated with endothelial cell (EC) survival following transplantation however their exact role has yet to be elucidated in respect to controlling inflammation. In this study we created mice expressing murine A1 (Bfl-1), a Bcl-2 family member, under the control of the human ICAM-2 promoter. Constitutive expression of A1 in murine vascular ECs conferred protection from cell death induced by the pro-inflammatory cytokine TNF-Ī±. Importantly, in a mouse model of heart allograft transplantation, expression of A1 in vascular endothelium increased survival in the absence of CD8+ T cells. Better graft outcome in mice receiving an A1 transgenic heart correlated with a reduced immune infiltration, which maybe related to increased EC survival and reduced expression of adhesion molecules on ECs. In conclusion, constitutive expression of the anti-apoptotic molecule Bfl1 (A1) in murine vascular ECs leads to prolonged allograft survival due to modifying inflammation

    An allele of IKZF1 (Ikaros) conferring susceptibility to childhood acute lymphoblastic leukemia protects against type 1 diabetes.

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    OBJECTIVE: IKZF1 encoding Ikaros, an essential regulator of lymphopoiesis and immune homeostasis, has been implicated in the development of childhood acute lymphoblastic leukemia (C-ALL). Because recent genome-wide association (GWA) studies have linked a region of the 3'-UTR of IKZF1 with C-ALL susceptibility, we tested whether IKZF1 is associated with the autoimmune disease type 1 diabetes. RESEARCH DESIGN AND METHODS: rs10272724 (T>C) near IKZF1 at 7p12 was genotyped in 8,333 individuals with type 1 diabetes, 9,947 control subjects, and 3,997 families of European ancestry. Association was tested using logistic regression in the case-control data and by the transmission disequilibrium test in the families. Expression data for IKZF1 by rs10272724 genotype were obtained using quantitative PCR of mRNA/cDNA generated from peripheral blood mononuclear cells from 88 individuals, whereas expression data for five other neighboring genes were obtained from the online Genevar dataset. RESULTS: The minor allele of rs10272724 (C) was found to be protective from type 1 diabetes (odds ratio 0.87 [95% CI 0.83-0.91]; P = 1.1 Ɨ 10(-11)). rs10272724 was not correlated with levels of two transcripts of IKZF1 in peripheral blood mononuclear cells. CONCLUSIONS: The major susceptibility genotype for C-ALL confers protection from type 1 diabetes. Our finding strengthens the link between autoimmunity and lymphoid cancers. Further investigation is warranted for the genetic effect marked by rs10272724, its impact on IKZF1, and the role of Ikaros and other family members, Ailios (IKZF3) and Eos (IKZF4), in autoimmunity

    A refresh of the top 10 research priorities in cystic fibrosis

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    In 2018 we published the James Lind Alliance (JLA) top 10 priorities for clinical research in cystic fibrosis (CF), chosen jointly by the patient and clinical communities. These priorities have led to new research funding. To establish whether priorities have changed with novel modulator therapies, we undertook an online international update through a series of surveys and a workshop. Patients and clinicians (n=1417) chose the refreshed top 10 from 971 new research questions (suggested by patients and clinicians) and 15 questions from 2018. We are working with the international community to promote research based on these refreshed top 10 priorities

    Respiratory syncytial virus in young children: community cohort study integrating serological surveys, questionnaire and electronic health records, Born in Bradford cohort, England, 2008 to 2013.

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    BackgroundBronchiolitis caused by respiratory syncytial virus (RSV) is a major cause of mortality and morbidity in infants.AimTo describe RSV epidemiology in children in the community in a high-income setting.MethodsWe used stored blood samples from the United Kingdom Born in Bradford cohort study that had been collected at birth, ageā€‰1 and 2ā€‰years old, tested for IgG RSV postfusion F antibody and linked to questionnaires and primary and hospital care records. We used finite mixture models to classify children as RSV infected/not infected according to their antibody concentrations at ageā€‰1 and 2ā€‰years. We assessed risk factors for primary RSV infection at each age using Poisson regression models.ResultsThe study cohort included 700 children with cord blood samples; 490 had additional blood samples taken at both ages 1 and 2ā€‰years old. Of these 490 children, 258 (53%;ā€‰95% confidence interval (CI):ā€‰48-57%) were first infected with RSV at ageā€‰1, 99 of whom (38%;ā€‰95%ā€‰CI:ā€‰33-43%) had been in contact with healthcare during peak RSV season (November-January). Having older siblings, birth in October-June and attending formal childcare were associated with risk of RSV infection in infancy. By ageā€‰2, a further 164 of 490 children (33%;ā€‰95%ā€‰CI:ā€‰29-38%) had been infected.ConclusionOver half of children experienced RSV infection in infancy, a further one third had evidence of primary RSV infection by ageā€‰2, and one in seven remained seronegative by their second birthday. These findings will inform future analyses to assess the cost-effectiveness of RSV vaccination programmes in high-income settings
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