1,287 research outputs found

    Dissimilar response of plant and soil biota communities to long-term nutrient adition in grasslands

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    The long-term effect of fertilizers on plant diversity and productivity is well known, but long-term effects on soil biota communities have received relatively little attention. Here, we used an exceptional long-lasting (>40 years) grassland fertilization experiment to investigate the long-term effect of Ca, N, PK, and NPK addition on the productivity and diversity of both vegetation and soil biota. Whereas plant diversity increased by liming and decreased by N and NPK, the diversity of nematodes, collembolans, mites, and enchytraeids increased by N, PK, or NPK. Fertilization with NPK and PK increased plant biomass and biomass of enchytraeids and collembolans. Biomass of nematodes and earthworms increased by liming. Our results suggest that soil diversity might be driven by plant productivity rather than by plant diversity. This may imply that the selection of measures for restoring or conserving plant diversity may decrease soil biota diversity. This needs to be tested in future experiment

    Post natal care in Bubi district deserves more attention

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    A CAJM medical article.Objectives: To establish whether, where and when women in Bubi District attend Post Natal Care (PNC), the factors that influence attendance, the quality of services and traditional or cultural practices felated to PNC. Design: A cross sectional survey. Setting: Bubi District, Matebeleland North Province, Zimbabwe. Subjects: A multistage sample of 200 women with a child aged three to 12 months, convenience samples of .96 women with a child zero to 12 months who had attended PNC; 112 elderly women from the community and 10 nurses. Main Outcome Measures: PNC attendance, place and timing of PNC visit, quality of PNC, knowledge and attitudes towards PNC and traditional practices Results: 61% of the women had attended PNC. Factors associated with non-attendance were higher age and parity, home delivery and long distance between home and health facility. Almost all women attended PNC in a district health facility. Eighty three percent were seen at six weeks post par turn. Forty percent of the mothers and 36.1% of the babies had received a full examination, but 37.7% and 4.9% respectively had not been examined at all. Nine of the 10 nurses interviewed were not aware of a PNC policy. Knowledge on PNC among the women in the community was poor. Some potentially beneficial and harmful traditional practices related to mother and baby were identified. Conclusion: PNC attendance in this study was almost three times the attendance reported through the routine National Health Information System, but lower than elsewhere in Zimbabwe. The quality of the services was rather poor and more geared towards the baby than the mother. Both health workers and the community need to better understand the importance of PNC. Because the first two weeks postpartum is the period with highest morbidity and mortality, women should be advised to make a PNC visit within 14 days, or whenever they have problems, rather than at six weeks. All health facilities, including the mobile teams should be able to offer PNC. There is need to develop an ‘ evidence-based’ PNC policy to guide nurses on what to offer to both mother and baby, also taking into consideration common traditional practices

    A systematic correlation between two-dimensional flow topology and the abstract statistics of turbulence

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    Velocity differences in the direct enstrophy cascade of two-dimensional turbulence are correlated with the underlying flow topology. The statistics of the transverse and longitudinal velocity differences are found to be governed by different structures. The wings of the transverse distribution are dominated by strong vortex centers, whereas, the tails of the longitudinal differences are dominated by saddles. Viewed in the framework of earlier theoretical work this result suggests that the transfer of enstrophy to smaller scales is accomplished in regions of the flow dominated by saddles.Comment: 4 pages, 4 figure

    The Nasal Microbiome in ANCA-Associated Vasculitis:Picking the Nose for Clues on Disease Pathogenesis

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    PURPOSE OF REVIEW: The onset and progression of small vessel vasculitis associated with anti-neutrophil cytoplasmic antibodies has been linked to microbial infections. Here, we provide a brief overview of the association of nasal colonization of Staphylococcus aureus with ANCA-associated vasculitis (AAV) and discuss several recent studies mapping the nasal microbiome in AAV patients in particular. RECENT FINDINGS: Nasal microbiome studies revealed dysbiosis as a common trait in active AAV which tends to normalize upon immunosuppressive treatment and quiescent disease. However, due to differences in study design, patient selection, and methodology, the reported microbiome profiles differ considerably precluding conclusions on causal relationships. SUMMARY: The microbiome is an emerging area of research in AAV warranting further investigation. Ideally, such studies should be combined with mechanistic studies to unravel key elements related to host-microbe interactions and their relevance for AAV pathogenesis

    A biological indicator for soil quality

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    Are Steadily Moving Crystals Unstable?

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    We study the dynamics of small fluctuations about the uniform state of a crystal moving through a dissipative medium, e.g. a sedimenting colloidal crystal or a moving flux lattice, using a set of continuum equations for the displacement fields, and a one-dimensional driven lattice-gas model for the coupled concentration and tilt fields. For the colloidal crystal we predict a continuous nonequilibrium phase transition to a clumped state above a critical Peclet number.Comment: 4 pages, revtex, 2 .eps figures, uses epsf.sty; To be published in Phys. Rev. Lett. This version is substantially rewritten but the essential content is the same as befor

    Implications of the new MRI-based rectum definition according to the sigmoid take-off:multicentre cohort study

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    Background: The introduction of the sigmoid take-off definition might lead to a shift from rectal cancers to sigmoid cancers. The aim of this retrospective cohort study was to determine the clinical impact of the new definition. Methods: In this multicentre retrospective cohort study, patients were included if they underwent an elective, curative total mesorectal excision for non-metastasized rectal cancer between January 2015 and December 2017, were registered in the Dutch Colorectal Audit as having a rectal cancer according to the previous definition, and if MRI was available. All selected rectal cancer cases were reassessed using the sigmoid take-off definition. The primary outcome was the number of patients reassessed with a sigmoid cancer. Secondary outcomes included differences between the newly defined rectal and sigmoid cancer patients in treatment, perioperative results, and 3-year oncological outcomes (overall and disease-free survivals, and local and systemic recurrences). Results: Out of 1742 eligible patients, 1302 rectal cancer patients were included. Of these, 170 (13.1 per cent) were reclassified as having sigmoid cancer. Among these, 93 patients (54.7 per cent) would have been offered another adjuvant or neoadjuvant treatment according to the Dutch guideline. Patients with a sigmoid tumour after reassessment had a lower 30-day postoperative complication rate (33.5 versus 48.3 per cent, P &lt; 0.001), lower reintervention rate (8.8 versus 17.4 per cent, P &lt; 0.007), and a shorter length of stay (a median of 5 days (i.q.r. 4-7) versus a median of 6 days (i.q.r. 5-9), P &lt; 0.001). Three-year oncological outcomes were comparable. Conclusion: Using the anatomical landmark of the sigmoid take-off, 13.1 per cent of the previously classified patients with rectal cancer had sigmoid cancer, and 54.7 per cent of these patients would have been treated differently with regard to neoadjuvant therapy or adjuvant therapy.</p

    On the dual cascade in two-dimensional turbulence

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    We study the dual cascade scenario for two-dimensional turbulence driven by a spectrally localized forcing applied over a finite wavenumber range [k_\min,k_\max] (with k_\min > 0) such that the respective energy and enstrophy injection rates ϵ\epsilon and η\eta satisfy k_\min^2\epsilon\le\eta\le k_\max^2\epsilon. The classical Kraichnan--Leith--Batchelor paradigm, based on the simultaneous conservation of energy and enstrophy and the scale-selectivity of the molecular viscosity, requires that the domain be unbounded in both directions. For two-dimensional turbulence either in a doubly periodic domain or in an unbounded channel with a periodic boundary condition in the across-channel direction, a direct enstrophy cascade is not possible. In the usual case where the forcing wavenumber is no greater than the geometric mean of the integral and dissipation wavenumbers, constant spectral slopes must satisfy β>5\beta>5 and α+β8\alpha+\beta\ge8, where α-\alpha (β-\beta) is the asymptotic slope of the range of wavenumbers lower (higher) than the forcing wavenumber. The influence of a large-scale dissipation on the realizability of a dual cascade is analyzed. We discuss the consequences for numerical simulations attempting to mimic the classical unbounded picture in a bounded domain.Comment: 22 pages, to appear in Physica
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