417 research outputs found

    Limited vertical CO2 transport in stems of mature boreal Pinus sylvestris trees

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    Several studies have suggested that CO2 transport in the transpiration stream can considerably bias estimates of root and stem respiration in ring-porous and diffuse-porous tree species. Whether this also happens in species with tracheid xylem anatomy and lower sap flow rates, such as conifers, is currently unclear. We infused C-13-labelled solution into the xylem near the base of two 90-year-old Pinus sylvestris L. trees. A custom-built gas exchange system and an online isotopic analyser were used to sample the CO2 efflux and its isotopic composition continuously from four positions along the bole and one upper canopy shoot in each tree. Phloem and needle tissue C-13 enrichment was also evaluated at these positions. Most of the C-13 label was lost by diffusion within a few metres of the infusion point indicating rapid CO2 loss during vertical xylem transport. No C-13 enrichment was detected in the upper bole needle tissues. Furthermore, mass balance calculations showed that c. 97% of the locally respired CO2 diffused radially to the atmosphere. Our results support the notion that xylem CO2 transport is of limited magnitude in conifers. This implies that the concerns that stem transport of CO2 derived from root respiration biases chamber-based estimates of forest carbon cycling may be unwarranted for mature conifer stands.Peer reviewe

    Large Mammals and Wetland utilization: a case study in Yankari Game Reserve Nigeria

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    The African plain harbours high abundance and diversity of mammals, most of which are confined to protected areas (PAs) due to anthro‐ pogenic threats (Craigie et al., 2010; Dirzo et al., 2014; Estes, 1999; Kingdon, 1997). Also, PAs face problems of hunting, logging and live‐ stock grazing, conflict of interest and poor management (Caro, 2001; Dharmaratne, Sang, &Walling, 2000; Gardner et al., 2009; Geldmann et al., 2015; Geldmann et al., 2015; Hall, Harris, Medjibe, & Ashton, 2003; Pressey, 1994; Salum, Eustace, Malata, & Mbangwa, 2017; Thuiller, 2007), consequently disrupting conservation goals, effective monitor‐ ing and understanding of habitat utilisation dynamics of mammals. Although wetlands are important habitats for sustaining animal populations, there is a widespread trend of increasing degradation of these habitats (Fynn, Chase, & Rӧder, 2014) and dearth of infor‐ mation pertaining to wetland utilisation in most PAs. While this is integral for effective conservation practice, few studies focus on this area in Africa (Arzamendia, Cassini, & Vila, 2006; Kumar, Mudappa, & Raman, 2010; Rahman et al., 2017). Here, we investigated the wet‐ land utilisation dynamics of large mammals in Yankari Game Reserve (YGR). The objective was to determine abundance, density and di‐ versity of large mammals and whether these variables were associ‐ ated with wetland size and time of da

    Expression of Concern: Redox modification of cysteine residues regulates the cytokine activity of high mobility group box-1 (HMGB1) (Molecular Medicine (2012) 18 (250-259) DOI: 10.2119/molmed.2011.00389)

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    © The Author(s). 2020. The Editors-in-Chief would like to alert readers that this article (Yang et al. 2012) is part of an investigation being conducted by the journal following the conclusions of an institutional enquiry at the University of Liverpool with respect to the quantitative mass spectrometrygenerated results regarding acetylated and redox-modified HMGB1. Appropriate editorial action will be taken once the investigation is concluded. Huan Yang, Peter Lundbäck, Lars Ottosson, Helena Erlandsson-Harris, Emilie Venereau, Marco E. Bianchi, Yousef Al-Abed, Ulf Andersson, and Kevin J. Tracey agree to this editorial expression of concern. Daniel J. Antoine has not responded to any correspondence from the editor/publisher about this editorial expression of concern

    Circannual variation in blood parasitism in a sub-Saharan migrant passerine bird, the garden warbler

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    Knowing the natural dynamics of pathogens in migratory birds is important, for example, to understand the factors that influence the transport of pathogens to and their transmission in new geographical areas, whereas the transmission of other pathogens might be restricted to a specific area. We studied haemosporidian blood parasites of the genera Plasmodium, Haemoproteus and Leucocytozoon in a migratory bird, the garden warbler Sylvia borin. Birds were sampled in spring, summer and early autumn at breeding grounds in Sweden, on migration at Capri, Italy and on arrival and departure from wintering staging areas in West Africa: mapping recoveries of garden warblers ringed in Fennoscandia and Capri showed that these sites are most probably on the migratory flyway of garden warblers breeding at Kvismaren. Overall, haemosporidian prevalence was 39%, involving 24 different parasite lineages. Prevalence varied significantly over the migratory cycle, with relatively high prevalence of blood parasites in the population on breeding grounds and at the onset of autumn migration, followed by marked declines in prevalence during migration both on spring and autumn passage. Importantly, we found that when examining circannual variation in the different lineages, significantly different prevalence profiles emerged both between and within genera. Our results suggest that differences in prevalence profiles are the result of either different parasite transmission strategies or coevolution between the host and the various parasite lineages. When separating parasites into common vs. rare lineages, we found that two peaks in the prevalence of rare parasites occur; on arrival at Swedish breeding grounds, and after the wintering period in Africa. Our results stress the importance of appropriate taxonomic resolution when examining host-parasite interactions, as variation in prevalence both between and within parasite genera can show markedly different patterns

    The impact of psychological factors on recovery from injury: a multicentre cohort study

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    Purpose Unintentional injuries have a significant long-term health impact in working age adults. Depression, anxiety and post-traumatic stress disorder are common post-injury, but their impact on self-reported recovery has not been investigated in general injury populations. This study investigated the role of psychological predictors 1 month post-injury in subsequent self-reported recovery from injury in working-aged adults. Methods A multicentre cohort study was conducted of 668 unintentionally injured adults admitted to five UK hospitals followed up at 1, 2, 4 and 12 months post-injury. Logistic regression explored relationships between psychological morbidity 1 month post-injury and self-reported recovery 12 months post-injury, adjusting for health, demographic, injury and socio-legal factors. Multiple imputations were used to impute missing values. Results A total of 668 adults participated at baseline, 77% followed up at 1 month and 63% at 12 months, of whom 383 (57%) were included in the main analysis. Multiple imputation analysis included all 668 participants. Increasing levels of depression scores and increasing levels of pain at 1 month and an increasing number of nights in hospital were associated with significantly reduced odds of recovery at 12 months, adjusting for age, sex, centre, employment and deprivation. The findings were similar in the multiple imputation analysis, except that pain had borderline statistical significance. Conclusions Depression 1 month post-injury is an important predictor of recovery, but other factors, especially pain and nights spent in hospital, also predict recovery. Identifying and managing depression and providing adequate pain control are essential in clinical care post-injury

    Development of a neuro-fuzzy technique for automated parameter optimization of inverse treatment planning

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    <p>Abstract</p> <p>Background</p> <p>Parameter optimization in the process of inverse treatment planning for intensity modulated radiation therapy (IMRT) is mainly conducted by human planners in order to create a plan with the desired dose distribution. To automate this tedious process, an artificial intelligence (AI) guided system was developed and examined.</p> <p>Methods</p> <p>The AI system can automatically accomplish the optimization process based on prior knowledge operated by several fuzzy inference systems (FIS). Prior knowledge, which was collected from human planners during their routine trial-and-error process of inverse planning, has first to be "translated" to a set of "if-then rules" for driving the FISs. To minimize subjective error which could be costly during this knowledge acquisition process, it is necessary to find a quantitative method to automatically accomplish this task. A well-developed machine learning technique, based on an adaptive neuro fuzzy inference system (ANFIS), was introduced in this study. Based on this approach, prior knowledge of a fuzzy inference system can be quickly collected from observation data (clinically used constraints). The learning capability and the accuracy of such a system were analyzed by generating multiple FIS from data collected from an AI system with known settings and rules.</p> <p>Results</p> <p>Multiple analyses showed good agreements of FIS and ANFIS according to rules (error of the output values of ANFIS based on the training data from FIS of 7.77 ± 0.02%) and membership functions (3.9%), thus suggesting that the "behavior" of an FIS can be propagated to another, based on this process. The initial experimental results on a clinical case showed that ANFIS is an effective way to build FIS from practical data, and analysis of ANFIS and FIS with clinical cases showed good planning results provided by ANFIS. OAR volumes encompassed by characteristic percentages of isodoses were reduced by a mean of between 0 and 28%.</p> <p>Conclusion</p> <p>The study demonstrated a feasible way to automatically perform parameter optimization of inverse treatment planning under guidance of prior knowledge without human intervention other than providing a set of constraints that have proven clinically useful in a given setting.</p
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