9,809 research outputs found

    Using local experts as benchmarks for household local ecological knowledge: scoring in South African savannas

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    It is well recognised that local ecological knowledge is an important facet of natural resource management in rural regions of the developing world. However, techniques to assess levels and to integrate it into formal or informal management approaches require further development. In particular, quantitative tools are missing, which would allow more robust analysis of the factors that positively or negatively affect local ecological knowledge and vice versa. This paper reports on a quick assessment approach that provides a quantitative score of generalist local ecological knowledge at the household level. It does so by comparing responses to the knowledge of local people identified as experts within the community. In this way it is both locally constructed and contextualized, and thereby avoids pitfalls of trying to score local ecological knowledge relative to conventional scientific knowledge which frequently cannot account for local constructs. The approach is applied at eight villages throughout the savanna biome in South Africa

    Periodic remeasurement of the Gus Pearson Natural Area

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    The 240-acre Gus Pearson Natural Area in Fort Valley Experimental Forest, Arizona, comprises an important historical and ecological site because of the presence of dense stands of old-growth trees and detailed records of stand growth and mortality since 1920. Permanently tagged trees were remeasured after the 2000 growing season. This measurement is the twelfth decadal or bi-decadal measurement since establishment of the study area. This report includes electronic files with tree data and data summaries for selected subplots . Inventory procedures and tree condition codes used in 2000 are documented. The major trends in the 80-year measurement period were: (1) long-term decline in basal area growth, (2) shifts in the relative growth of larger versus smaller trees, and (3) reduced growth and increased mortality, especially since 1945. These trends are consistent with other research findings at the site

    Spectral Signatures of Hydrogen Thioperoxide (HOSH) and Hydrogen Persulfide (HSSH): Possible Molecular Sulfur Sinks in the Dense ISM

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    For decades, sulfur has remained underdetected in molecular form within the dense interstellar medium (ISM), and somewhere a molecular sulfur sink exists where it may be hiding. With the discovery of hydrogen peroxide (HOOH) in the ISM in 2011, a natural starting point may be found in sulfur-bearing analogs that are chemically similar to HOOH: hydrogen thioperoxide (HOSH) and hydrogen persulfide (HSSH). The present theoretical study couples the accuracy in the anharmonic fundamental vibrational frequencies from the explicitly correlated coupled cluster theory with the accurate rotational constants provided by canonical high-level coupled cluster theory to produce rovibrational spectra for use in the potential observation of HOSH and HSSH. The ν6 mode for HSSH at 886.1 cm−1 is within 0.2 cm−1 of the gas-phase experiment, and the B0 rotational constant for HSSH of 6979.5 MHz is within 9.0 MHz of the experimental benchmarks, implying that the unknown spectral features (such as the first overtones and combination bands) provided herein are similarly accurate. Notably, a previous experimentally-attributed 2ν1 mode, at 7041.8 cm−1, has been reassigned to the ν1 + ν5 combination band based on the present work’s ν1 + ν5 value at 7034.3 cm−1. The most intense vibrational transitions for each molecule are the torsions, with HOSH having a more intense transition of 72 km/mol compared to HSSH’s intensity of 14 km/mol. Furthermore, HOSH has a larger net dipole moment of 1.60 D compared to HSSH’s 1.15 D. While HOSH may be the more likely candidate of the two for possible astronomical observation via vibrational spectroscopy due to the notable difference in their intensities, both HSSH and HOSH have large enough net dipole moments to be detectable by rotational spectroscopy to discover the role these molecules may have as possible molecular sulfur sinks in the dense ISM

    Suprasellar Clear Cell Meningioma in an Infant : Case report

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    Clear cell meningiomas are an uncommon subtype of meningioma rarely seen in infancy. We report a case of clear cell meningioma in an 8-month-old male infant. He presented at the Lagos University Teaching Hospital, Lagos, Nigeria, in 2015 with persistent vomiting, poor feeding and failure to thrive over a four month period. Generalised hypertonia and hyperreflexia were noted on examination. Computed tomography of the brain revealed a huge largely isodense suprasellar mass with a hypodense core. The tumour, which measured 6 x 5 x 4 cm, enhanced non-uniformly with contrast injection and extended to occlude the third ventricle. The patient underwent a bifrontal craniotomy with subtotal tumour excision. Six hours postoperatively, he went into cardiac arrest and could not be resuscitated. A histological diagnosis of clear cell meningioma was made as the tumour cells were immunoreactive to epithelial membrane antigen, S100 protein and vimentin. This case of clear cell meningioma was unusual due to its early occurrence and supratentorial location

    Mechanical Circulatory Support of the Critically Ill Child Awaiting Heart Transplantation

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    The majority of children awaiting heart transplantation require inotropic support, mechanical ventilation, and/or extracorporeal membrane oxygenation (ECMO) support. Unfortunately, due to the limited pool of organs, many of these children do not survive to transplant. Mechanical circulatory support of the failing heart in pediatrics is a new and rapidly developing field world-wide. It is utilized in children with acute congestive heart failure associated with congenital heart disease, cardiomyopathy, and myocarditis, both as a bridge to transplantation and as a bridge to myocardial recovery. The current arsenal of mechanical assist devices available for children is limited to ECMO, intra-aortic balloon counterpulsation, centrifugal pump ventricular assist devices, the DeBakey ventricular assist device Child; the Thoratec ventricular assist device; and the Berlin Heart. In the spring of 2004, five contracts were awarded by the National Heart, Lung and Blood Institute to support preclinical development for a range of pediatric ventricular assist devices and similar circulatory support systems. The support of early development efforts provided by this program is expected to yield several devices that will be ready for clinical trials within the next few years. Our work reviews the current international experience with mechanical circulatory support in children and summarizes our own experience since 2005 with the Berlin Heart, comparing the indications for use, length of support, and outcome between these modalities
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