427 research outputs found

    Role, importance and vulnerability of top predators on the Great Barrier Reef: a review

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    The purpose of this review is to evaluate the ecological role of predators on the Great Barrier Reef (GBR), their vulnerability to human activities and their contribution to ecosystem and economic values. Marine systems around the world are under increasing pressure, from the localised anthropogenic impacts of fishing and terrestrial run-off to the global pressures of climate change. There is concern over exploitation and declining numbers and biomass of large marine predators, worldwide and on the GBR. Understanding the role of predation and the consequences of predator loss is a priority for managers. To better understand the link between the protection of exploited fish stocks, the enhancement of the GBR’s overall resilience and the maintenance of ecosystem structure and function, this review seeks to answer the following questions:ID: 181

    A. D. Ayling requesting a certificate of discharge of private Henry N. Hatch

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    https://digitalmaine.com/arc_me_militia/1019/thumbnail.jp

    Flow cytometry follow-up analysis of peripheral blood leukocyte subpopulations in calves experimentally infected with field isolates of Mycoplasma bovis

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    Changes in peripheral blood leukocyte subpopulations were investigated in calves challenged intratracheally with three different Mycoplasma bovis isolates in Groups E1, E2, and E3. The controls received a placebo. Blood samples were collected before challenge and then at days 1 to 7, 14, 21 and 28. White blood cells (WBC), polymorphonuclear leukocytes (PMNLs), lymphocytes (LYMs), monocytes, eosinophils and basophils (mid-size cells, MID), as well as CD2+, CD4+, CD8+, WC4+ lymphocyte subsets with CD4:CD8 ratio were also analysed. A transient increase of WBC and PMNLs in all challenged calves was observed on day 1. Increased LYM counts were observed in E1 throughout the study, whereas in E2 the LYM counts were higher only between days 14 and 28, and consistently lower in E3. The MID count had broadly comparable values for all groups. Stimulation of the CD2+ response was observed in E2 and E3 in contrast with E1 which had a lower CD2+ throughout. The CD4+ response was dominant in E1 and E2, whereas in E3 a parallel CD4+ and CD8+ stimulation was observed. The B-cell response (WC4+) and an increased CD4:CD8 ratio was most apparent in E1. The main host responses to M. bovis infections are a stimulation of CD4+ cells and an enhancement of the WC4+ response

    Toward a Social Practice Theory of Relational Competing

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    This paper brings together the competitive dynamics and strategy-aspractice literatures to investigate relational competition. Drawing on a global ethnography of the reinsurance market, we develop the concept of micro-competitions, which are the focus of competitors’ everyday competitive practices. We find variation in relational or rivalrous competition by individual competitors across the phases of a micro-competition, between competitors within a micro-competition, and across multiple micro-competitions. These variations arise from the interplay between the unfolding competitive arena and the implementation of each firm’s strategic portfolio. We develop a conceptual framework that makes four contributions to: relational competition; reconceptualizing action and response; elaborating on the awareness-motivation-capability framework within competitive dynamics; and the recursive dynamic by which implementing strategy inside firms shapes, and is shaped by, the competitive arena

    VNTR analysis reveals unexpected genetic diversity within Mycoplasma agalactiae, the main causative agent of contagious agalactia

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    <p>Abstract</p> <p>Background</p> <p><it>Mycoplasma agalactiae </it>is the main cause of contagious agalactia, a serious disease of sheep and goats, which has major clinical and economic impacts. Previous studies of <it>M. agalactiae </it>have shown it to be unusually homogeneous and there are currently no available epidemiological techniques which enable a high degree of strain differentiation.</p> <p>Results</p> <p>We have developed variable number tandem repeat (VNTR) analysis using the sequenced genome of the <it>M. agalactiae </it>type strain PG2. The PG2 genome was found to be replete with tandem repeat sequences and 4 were chosen for further analysis. VNTR 5 was located within the hypothetical protein MAG6170 a predicted lipoprotein. VNTR 14 was intergenic between the hypothetical protein MAG3350 and the hypothetical protein MAG3340. VNTR 17 was intergenic between the hypothetical protein MAG4060 and the hypothetical protein MAG4070 and VNTR 19 spanned the 5' end of the pseudogene for a lipoprotein MAG4310 and the 3' end of the hypothetical lipoprotein MAG4320.</p> <p>We have investigated the genetic diversity of 88 <it>M. agalactiae </it>isolates of wide geographic origin using VNTR analysis and compared it with pulsed field gel electrophoresis (PFGE) and random amplified polymorphic DNA (RAPD) analysis. Simpson's index of diversity was calculated to be 0.324 for PFGE and 0.574 for VNTR analysis. VNTR analysis revealed unexpected diversity within <it>M. agalactiae </it>with 9 different VNTR types discovered. Some correlation was found between geographical origin and the VNTR type of the isolates.</p> <p>Conclusion</p> <p>VNTR analysis represents a useful, rapid first-line test for use in molecular epidemiological analysis of <it>M. agalactiae </it>for outbreak tracing and control.</p

    <i>Mycoplasma ovipneumoniae </i>- A Primary Cause of Severe Pneumonia Epizootics in the Norwegian Muskox (<i>Ovibos moschatus</i>) Population

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    The Norwegian muskox (Ovibos moschatus) population lives on the high mountain plateau of Dovre and originates from animals introduced from Greenland. In the late summers of 2006 and 2012, severe outbreaks of pneumonia with mortality rates of 25-30% occurred. During the 2012 epidemic high quality samples from culled sick animals were obtained for microbiological and pathological examinations. High throughput sequencing (pyrosequencing) of pneumonic lung tissue revealed high concentrations of Mycoplasma ovipneumoniae in all six animals examined by this method and Pasteurella multocida subsp. multocida in four animals, whereas no virus sequences could be identified. Mycoplasma ovipneumoniae and P. multocida multocida were also isolated by culture. Using real time PCR on lung swabs, M. ovipneumoniae was detected in all of the 19 pneumonic lungs examined. Gross pathological examination revealed heavy consolidations primarily in the cranial parts of the lungs and it also identified one case of otitis media. Histologically, lung lesions were characterized as acute to subacute mixed exudative and moderately proliferative bronchoalveolar pneumonia. Immunohistochemical (IHC) examination revealed high load of M. ovipneumoniae antigens within lung lesions, with particularly intensive staining in the neutrophils. Similar IHC finding were observed in archived lung tissue blocks from animals examined during the 2006 epidemic. An M. ovipneumoniae specific ELISA was applied on bio-banked muskox sera from stray muskoxen killed in the period 2004-2013 and sick muskoxen culled, as well as sera from wild reindeer (Rangifer tarandus tarandus) on Dovre and muskoxen from Greenland. Serology and mycoplasma culturing was also carried out on sheep that had been on pasture in the muskox area during the outbreak in 2012. Our findings indicated separate introductions of M. ovipneumoniae infection in 2006 and 2012 from infected co-grazing sheep. Salt licks shared by the two species were a possible route of transmitting infection

    Mechanisms of Manganese-Assisted Nonradiative Recombination in Cd(Mn)Se/Zn(Mn)Se Quantum Dots

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    Mechanisms of nonradiative recombination of electron-hole complexes in Cd(Mn)Se/Zn(Mn)Se quantum dots accompanied by interconfigurational excitations of Mn2+^{2+} ions are analyzed within the framework of single electron model of deep {\it 3d}-levels in semiconductors. In addition to the mechanisms caused by Coulomb and exchange interactions, which are related because of the Pauli principle, another mechanism due to {\it sp-d} mixing is considered. It is shown that the Coulomb mechanism reduces to long-range dipole-dipole energy transfer from photoexcited quantum dots to Mn2+^{2+} ions. The recombination due to the Coulomb mechanism is allowed for any states of Mn2+^{2+} ions and {\it e-h} complexes. In contrast, short-range exchange and sp−d{\it sp-d} recombinations are subject to spin selection rules, which are the result of strong {\it lh-hh} splitting of hole states in quantum dots. Estimates show that efficiency of the {\it sp-d} mechanism can considerably exceed that of the Coulomb mechanism. The phonon-assisted recombination and processes involving upper excited states of Mn2+^{2+} ions are studied. The increase in PL intensity of an ensemble of quantum dots in a magnetic field perpendicular to the sample growth plane observed earlier is analyzed as a possible manifestation of the spin-dependent recombination.Comment: 14 pages, 2 figure

    Quantitative faecal immunochemical test for patients with 'high risk' bowel symptoms: a prospective cohort study

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    Objectives: To evaluate whether quantitative measurement of faecal haemoglobin (f-Hb) using faecal immunochemical testing (FIT) can be used to rule out colorectal cancer (CRC) for patients who present to primary care with ‘high risk’ symptoms defined by national guidelines for urgent referral for suspected cancer (NICE NG12). / Design: Prospective cohort study carried out between April 2017 and March 2019. / Setting: 59 GP practices in London and 24 hospitals in England. / Participants: Symptomatic patients in England referred to the urgent CRC pathway who provided a faecal sample for FIT in addition to standard investigations for cancer. / Main outcome measures: CRC was confirmed by established clinical and histopathology procedures. f-Hb (μg per gram of stool) was measured in a central laboratory blinded to cancer outcome. We calculated sensitivity (percentage of patients with CRC who have f-Hb exceeding specified cut-offs); false-positive rate [FPR] (percentage of patients without CRC whose f-Hb exceeds the same cut-offs); and positive predictive value [PPV] (percentage of all patients with f-Hb above the cut-offs who have CRC). / Results: 4676 patients were recruited of whom 3596 patients were included (had a valid FIT test and a known definitive diagnosis). Among the 3596, median age was 67 years, 53% were female and 78% had colonoscopy. 90 patients were diagnosed with CRC, 7 with other cancers, and 3499 with no cancer found. f-Hb did not correlate with age, sex or ethnicity. Using f-Hb ≥4μg/g (lowest limit of detection), sensitivity, FPR and PPV were 87.8%, 27.0% and 7.7% respectively. Using f-Hb ≥10μg/g, the corresponding measures were 83.3%, 19.9% and 9.7%. 15 patients with CRC had f-Hb below 10μg/g. If FIT had been used at thresholds of 10μg/g or 4μg/g, 1 in 6 or 1 in 8 patients with cancer respectively would have been missed. If the absence of anaemia or abdominal pain is used alongside f-Hb 10 μg/g, only 1 in 18 cancers would be missed but 56% of people without CRC could potentially avoid further investigations including colonoscopies. / Conclusions: In our study, if FIT alone had been used to determine urgent referral for patients with ‘high risk’ symptoms for definitive cancer investigation, some patients with bowel cancer would not have been diagnosed. If used in conjunction with clinical features, particularly in the absence of anaemia, the efficacy of FIT is significantly improved. With appropriate safety netting, FIT could be used to focus secondary care diagnostic capacity on patients most at risk of CRC

    A Novel Rapid DNA Microarray Assay Enables Identification of 37 Mycoplasma Species and Highlights Multiple Mycoplasma Infections

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    Mycoplasmas comprise a conglomerate of pathogens and commensals occurring in humans and animals. The genus Mycoplasma alone contains more than 120 species at present, and new members are continuously being discovered. Therefore, it seems promising to use a single highly parallel detection assay rather than develop separate tests for each individual species. In this study, we have designed a DNA microarray carrying 70 oligonucleotide probes derived from the 23S rRNA gene and 86 probes from the tuf gene target regions. Following a PCR amplification and biotinylation step, hybridization on the array was shown to specifically identify 31 Mycoplasma spp., as well as 3 Acholeplasma spp. and 3 Ureaplasma spp. Members of the Mycoplasma mycoides cluster can be recognized at subgroup level. This procedure enables parallel detection of Mollicutes spp. occurring in humans, animals or cell culture, from mono- and multiple infections, in a single run. The main advantages of the microarray assay include ease of operation, rapidity, high information content, and affordability. The new test's analytical sensitivity is equivalent to that of real-time PCR and allows examination of field samples without the need for culture. When 60 field samples from ruminants and birds previously analyzed by denaturing-gradient gel electrophoresis (DGGE) were tested by the microarray assay both tests identified the same agent in 98.3% of the cases. Notably, microarray testing revealed an unexpectedly high proportion (35%) of multiple mycoplasma infections, i.e., substantially more than DGGE (15%). Two of the samples were found to contain four different Mycoplasma spp. This phenomenon deserves more attention, particularly its implications for epidemiology and treatment

    Faecal immunochemical test for patients with 'high-risk' bowel symptoms: a large prospective cohort study and updated literature review

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    Background: We evaluated whether faecal immunochemical testing (FIT) can rule out colorectal cancer (CRC) among patients presenting with ‘high-risk’ symptoms requiring definitive investigation. Methods: Three thousand five hundred and ninety-six symptomatic patients referred to the standard urgent CRC pathway were recruited in a multi-centre observational study. They completed FIT in addition to standard investigations. CRC miss rate (percentage of CRC cases with low quantitative faecal haemoglobin [f-Hb] measurement) and specificity (percentage of patients without cancer with low f-Hb) were calculated. We also provided an updated literature review. Results: Ninety patients had CRC. At f-Hb < 10 µg/g, the miss rate was 16.7% (specificity 80.1%). At f-Hb < 4 µg/g, the miss rate was 12.2% (specificity 73%), which became 3.3% if low FIT plus the absence of anaemia and abdominal pain were considered (specificity 51%). Within meta-analyses of 9 UK studies, the pooled miss rate was 7.2% (specificity 74%) for f-Hb < 4 µg/g. Discussion: FIT alone as a triage tool would miss an estimated 1 in 8 cases in our study (1 in 14 from meta-analysis), while many people without CRC could avoid investigations. FIT can focus secondary care diagnostic capacity on patients most at risk of CRC, but more work on safety netting is required before incorporating FIT triage into the urgent diagnostic pathway
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