3,284 research outputs found

    Multigene phylogeny and mating tests reveal three cryptic species related to Calonectria pauciramosa

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    Calonectria pauciramosa is a pathogen of numerous plant hosts worldwide. Recent studies have indicated that it included cryptic species, some of which are identified in this study. Isolates from various geographical origins were collected and compared based on morphology, DNA sequence data of the ß-tubulin, histone H3 and translation elongation factor-1 regions and mating compatibility. Comparisons of the DNA sequence data and mating compatibility revealed three new species. These included Ca. colombiana sp. nov. from Colombia, Ca. polizzii sp. nov. from Italy and Ca. zuluensis sp. nov. from South Africa, all of which had distinguishing morphological features. Based on DNA sequence data, Ca. brasiliensis is also elevated to species leve

    Calonectria species associated with cutting rot of Eucalyptus

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    Decline in the productivity of Eucalyptus hybrid cutting production in the Guangdong Province of China is linked to cutting rot associated with several Calonectria spp. The aim of this study was to identify these fungi using morphological and DNA sequence comparisons. Two previously undescribed Calonectria spp., Ca. pseudoreteaudii sp. nov. and Ca. cerciana sp. nov. were identified together with Ca. pauciramosa. Calonectria pseudoreteaudii resides in the Ca. reteaudii complex and Ca. cerciana is closely related to Ca. morganii. Connected to the discovery of Ca. pseudoreteaudii, species in the Ca. reteaudii complex were re-considered and the group is shown to accommodate two cryptic species. These originate from Australia and are described as Ca. queenslandica sp. nov. and Ca. terrae-reginae sp. nov

    Introgression of Brown Norway \u3cem\u3eCYP4A\u3c/em\u3e Genes onto the Dahl Salt-Sensitive Background Restores Vascular Function in SS-5\u3csup\u3eBN\u3c/sup\u3e Consomic Rats

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    The present study tested the hypothesis that the Dahl SS (salt-sensitive) rat has vascular dysfunction due, in part, to the up-regulation of the CYP4A/20-HETE (cytochrome P450 ω-hydroxylase 4A)/20-hydroxyeicosatetraenoic acid) system. To assess the role of vascular 20-HETE, SS rats were compared with SS-5BN consomic rats, carrying CYP4A alleles on chromosome 5 from the normotensive BN (Brown Norway) introgressed on to the SS genetic background. Cerebral arteries from SS-5BN rats had less CYP4A protein than arteries from SS rats fed either NS (normal-salt, 0.4% NaCl) or HS (high-salt, 4.0% NaCl) diet. ACh (acetylcholine)-induced dilation of MCAs (middle cerebral arteries) from SS and SS-5BN rats was present in SS-5BN rats fed on either an NS or HS diet, but absent in SS rats. In SS rats fed on either diet, ACh-induced dilation was restored by acute treatment with the CYP4A inhibitor DDMS (N-methyl-sulfonyl-12,12-dibromododec-11-enamide) or the 20-HETE antagonist 20-HEDE [20-hydroxyeicosa-6(Z),15(Z)-dienoic acid]. The restored response to ACh in DDMS-treated SS rats was inhibited by L-NAME (NGnitro-L-arginine methyl ester) and unaffected by indomethacin or MS-PPOH [N-methylsulfonyl-6-(2-propargyloxyphenyl)hexanamide]. Vascular relaxation responses to the NO donor C5FeN6Na2O were intact in both SS and SS-5BN rats and unaffected by the acute addition of DDMS, indicating that the vascular dysfunction of the SS rat is due to a reduced bioavailability of NO instead of failure of the VSMCs (vascular smooth muscle cells) to respond to the vasodilator. Superoxide levels in cerebral arteries of SS-5BN rats [evaluated semi-quantitatively by DHE (dihydroethidium) fluorescence] were lower than those in the arteries of SS rats. These findings indicate that SS rats have an up-regulation of the CYP4A/20-HETE pathway resulting in elevated ROS (reactive oxygen species) and reduced NO bioavailability causing vascular dysfunction

    Cost effective use of liquid nitrogen in cryogenic wind tunnels

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    A method of reliquefying from 12 to 19% of the nitrogen exhaust gas from a cryogenic wind tunnel has been developed. Technical feasibility and cost effectiveness of the system depends on performance of an innovative positive displacement expander which requires scale model testing to confirm design studies. The existing cryogenic system at the 0.3-m transonic cryogenic tunnel has been surveyed and extensive upgrades proposed. Upgrades are generally cost effective and may be implemented immediately since they are based on established technology

    Israel Cook Russell

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    Wood-rotting Basidiomycetes--Itasca State Park Annotated List

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    This study reports 216 species of wood-rotting Basidiomycetes from Lake Itasca State Park in Minnesota. Of these, two species, Gloeocystidiellum heimii Boid. and Phanerochaete cumulodentata (Nikol) Parm., are reported for the first time from North America

    Risk factors for myocardial infarction and stroke in Africa

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    Background: Definitive information on the strength of association between various risk factors and cardiovascular disease in Africa is lacking. Objective: We conducted a systematic review of studies investigating risk factors for acute myocardial infarction (AMI) and stroke in Africa. Data sources: We searched Medline and Embase as well as the reference lists of the included articles. Study eligibility criteria: We included case-control and cohort studies conducted in an African country, which assessed risk factors for first episodes of (AMI) or stroke in people of any age. Methods: Two independent reviewers screened studies for eligibility, extracted data and assessed study quality. We described measures of association (odds ratios) with confidence intervals of risk factors for AMI and stroke separately. Results: Twelve articles reporting results from five case-control studies met our inclusion criteria but only one study (INTERHEART ) investigated risk factors for AMI. No eligible cohort studies were identified. The direction of association for established risk factors for AMI and stroke seem to be similar globally but the strength of association of various risk factors varies between countries and within African ethnic groups. In Africa, diabetes and hypertension had the highest risk associated with AMI and hypertension was the strongest risk factor for stroke. Overall, the quality of the included case-control studies was good. Conclusions and implications: Our results confirm the urgent need for prospective studies investigating risk factors for AMI and stroke in African populations. A few high quality case-control studies exist but these do not adequately represent the cultural and genetic diversity in Africa, or the influence of infections on cardiovascular outcomes. Dynamic risk factors that rely on self-report such as diet, physical activity and stress will be better assessed through longitudinal cohort studies

    Scanning nano-spin ensemble microscope for nanoscale magnetic and thermal imaging

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    Quantum sensors based on solid-state spins provide tremendous opportunities in a wide range of fields from basic physics and chemistry to biomedical imaging. However, integrating them into a scanning probe microscope to enable practical, nanoscale quantum imaging is a highly challenging task. Recently, the use of single spins in diamond in conjunction with atomic force microscopy techniques has allowed significant progress towards this goal, but generalisation of this approach has so far been impeded by long acquisition times or by the absence of simultaneous topographic information. Here we report on a scanning quantum probe microscope which solves both issues, by employing a nano-spin ensemble hosted in a nanodiamond. This approach provides up to an order of magnitude gain in acquisition time, whilst preserving sub-100 nm spatial resolution both for the quantum sensor and topographic images. We demonstrate two applications of this microscope. We first image nanoscale clusters of maghemite particles through both spin resonance spectroscopy and spin relaxometry, under ambient conditions. Our images reveal fast magnetic field fluctuations in addition to a static component, indicating the presence of both superparamagnetic and ferromagnetic particles. We next demonstrate a new imaging modality where the nano-spin ensemble is used as a thermometer. We use this technique to map the photo-induced heating generated by laser irradiation of a single gold nanoparticle in a fluid environment. This work paves the way towards new applications of quantum probe microscopy such as thermal/magnetic imaging of operating microelectronic devices and magnetic detection of ion channels in cell membranes.Comment: 22 pages including Supporting Information. Changes to v1: affiliations and funding information updated, plus minor revisions to the main tex

    Strengthening graduate employee commitment through internal marketing in the South African retail banking industry

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    Abstract: A strong internal marketing strategy can be critical to achieving and sustaining a competitive advantage as well as driving organisational change and enhanced organisational performance. This study sought to determine the influence of internal marketing mix elements on the satisfaction levels of recently employed graduates (GradDPs) within the retail banking industry in South Africa. The study also identified links between the satisfaction of GradDPs and their affective commitment in this context. A census approach to generating data was applied in the study by using a person-administered and an electronic survey method. Regression analysis was used to test the relationships proposed in the study. The results indicated that internal marketing significantly influences GradDP employee satisfaction within retail banks in South Africa and that a positive relationship exists between GradDP employee satisfaction and their affective commitment. The study results allowed for recommendations that retail banks provide training and support programmes to assist managers in developing a more participative style of leading. Such programmes would assist leaders in consulting employees more often and ensuring that they have sufficient autonomy when executing their work. It would also help leaders to create a safer GradDP employee environment that fosters openness, risk-taking and idea generation

    Events, processes, and the time of a killing

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    The paper proposes a novel solution to the problem of the time of a killing (ToK), which persistently besets theories of act-individuation. The solution proposed claims to expose a crucial wrong-headed assumption in the debate, according to which ToK is essentially a problem of locating some event that corresponds to the killing. The alternative proposal put forward here turns on recognizing a separate category of dynamic occurents, viz. processes. The paper does not aim to mount a comprehensive defense of process ontology, relying instead on extant defenses. The primary aim is rather to put process ontology to work in diagnosing the current state of play over ToK, and indeed in solving it
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