829 research outputs found

    Global priorities for conservation across multiple dimensions of mammalian diversity

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    Conservation priorities that are based on species distribution, endemism, and vulnerability may underrepresent biologically unique species as well as their functional roles and evolutionary histories. To ensure that priorities are biologically comprehensive, multiple dimensions of diversity must be considered. Further, understanding how the different dimensions relate to one another spatially is important for conservation prioritization, but the relationship remains poorly understood. Here, we use spatial conservation planning to (i) identify and compare priority regions for global mammal conservation across three key dimensions of biodiversity-taxonomic, phylogenetic, and traits-and (ii) determine the overlap of these regions with the locations of threatened species and existing protected areas. We show that priority areas for mammal conservation exhibit low overlap across the three dimensions, highlighting the need for an integrative approach for biodiversity conservation. Additionally, currently protected areas poorly represent the three dimensions of mammalian biodiversity. We identify areas of high conservation priority among and across the dimensions that should receive special attention for expanding the global protected area network. These high-priority areas, combined with areas of high priority for other taxonomic groups and with social, economic, and political considerations, provide a biological foundation for future conservation planning efforts

    Chemical composition and minerals in pyrite ash of an abandoned sulphuric acid production plant

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    The extraction of sulphur produces a hematite-rich waste, known as roasted pyrite ash, which contains significant amounts of environmentally sensitive elements in variable concentrations and modes of occurrence. Whilst the mineralogy of roasted pyrite ash associated with iron or copper mining has been studied, as this is the main source of sulphur worldwide, the mineralogy, and more importantly, the characterization of submicron, ultrafine and nanoparticles, in coal-derived roasted pyrite ash remain to be resolved. In this work we provide essential data on the chemical composition and nanomineralogical assemblage of roasted pyrite ash. XRD, HR-TEM and FE-SEM were used to identify a large variety of minerals of anthropogenic origin. These phases result from highly complex chemical reactions occurring during the processing of coal pyrite of southern Brazil for sulphur extraction and further manufacture of sulphuric acid. Iron-rich submicron, ultrafine and nanoparticles within the ash may contain high proportions of toxic elements such as As, Se, U, among others. A number of elements, such as As, Cr, Cu, Co, La, Mn, Ni, Pb, Sb, Se, Sr, Ti, Zn, and Zr, were found to be present in individual nanoparticles and submicron, ultrafine and nanominerals (e.g. oxides, sulphates, clays) in concentrations of up to 5%. The study of nanominerals in roasted pyrite ash from coal rejects is important to develop an understanding on the nature of this by-product, and to assess the interaction between emitted nanominerals, ultra-fine particles, and atmospheric gases, rain or body fluids, and thus to evaluate the environmental and health impacts of pyrite ash materials

    Differences between blood and cerebrospinal fluid glial fibrillary Acidic protein levels: The effect of sample stability

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    Introduction: Recent evidence has shown that the marker of reactive astrogliosis, glial fibrillary acidic protein (GFAP), has a stronger relationship with cerebral amyloid beta (Aβ) pathology in blood than in cerebrospinal fluid (CSF). This study investigates if pre-analytical treatment of blood and CSF contribute to these unexpected findings. Methods: Paired CSF and serum samples from 49 individuals (Aβ-negative = 28; Aβ-positive = 21) underwent a series of seven freeze-thaw cycles (FTCs). All samples were analyzed for GFAP and neurofilament light (NfL) using single molecule array technology including a fresh unfrozen sample from each patient. Results: FTC significantly affected CSF GFAP concentration (−188.12 pg/ml per FTC) but not serum GFAP. In the same samples, NfL remained stable. Serum GFAP had a higher discrimination of Aβ burden than CSF GFAP, irrespective of FTC, which also included unfrozen samples. Discussion: This study demonstrates large stability differences of GFAP in CSF and serum. However, this disparity does not seem to fully explain the stronger association of serum GFAP with Aβ pathology. Further work should investigate mechanisms of GFAP release into the bloodstream under pathological conditions

    Plasma phospho-tau in Alzheimer’s disease: towards diagnostic and therapeutic trial applications

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    As the leading cause of dementia, Alzheimer's disease (AD) is a major burden on affected individuals, their families and caregivers, and healthcare systems. Although AD can be identified and diagnosed by cerebrospinal fluid or neuroimaging biomarkers that concord with neuropathological evidence and clinical symptoms, challenges regarding practicality and accessibility hinder their widespread availability and implementation. Consequently, many people with suspected cognitive impairment due to AD do not receive a biomarker-supported diagnosis. Blood biomarkers have the capacity to help expand access to AD diagnostics worldwide. One such promising biomarker is plasma phosphorylated tau (p-tau), which has demonstrated specificity to AD versus non-AD neurodegenerative diseases, and will be extremely important to inform on clinical diagnosis and eligibility for therapies that have recently been approved. This review provides an update on the diagnostic and prognostic performances of plasma p-tau181, p-tau217 and p-tau231, and their associations with in vivo and autopsy-verified diagnosis and pathological hallmarks. Additionally, we discuss potential applications and unanswered questions of plasma p-tau for therapeutic trials, given their recent addition to the biomarker toolbox for participant screening, recruitment and during-trial monitoring. Outstanding questions include assay standardization, threshold generation and biomarker verification in diverse cohorts reflective of the wider community attending memory clinics and included in clinical trials

    Theory of Magnetic Anisotropy in III_{1-x}Mn_{x}V Ferromagnets

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    We present a theory of magnetic anisotropy in III1xMnxV{\rm III}_{1-x}{\rm Mn}_{x}{\rm V} diluted magnetic semiconductors with carrier-induced ferromagnetism. The theory is based on four and six band envelope functions models for the valence band holes and a mean-field treatment of their exchange interactions with Mn++{\rm Mn}^{++} ions. We find that easy-axis reorientations can occur as a function of temperature, carrier density pp, and strain. The magnetic anisotropy in strain-free samples is predicted to have a p5/3p^{5/3} hole-density dependence at small pp, a p1p^{-1} dependence at large pp, and remarkably large values at intermediate densities. An explicit expression, valid at small pp, is given for the uniaxial contribution to the magnetic anisotropy due to unrelaxed epitaxial growth lattice-matching strains. Results of our numerical simulations are in agreement with magnetic anisotropy measurements on samples with both compressive and tensile strains. We predict that decreasing the hole density in current samples will lower the ferromagnetic transition temperature, but will increase the magnetic anisotropy energy and the coercivity.Comment: 15 pages, 15 figure

    Evaluation of sorghum silages of diferent genotypes with and without condensed tannins.

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    A total of 10 Sorghum cultivar: two lines (CMSXS114, T ) and (CMSXS165, WT ), six hybrids ( 9953101,T; 9953130,T; BR601, WT; BR701, T; BR700, T; and AG2005, WT and two varieties (BR501, WT; and BR506, WT) with 8 replications were ensiled in PVC silos of 3 kg per silo for 60 days and then analyzed for condensed tannins (CT) (colorimetric analysis by the butanol-HCl method), CP, NDF, ADF, and in vitro (IVDMD-24 and 48hs) digestibilities. Condensed tannins (CT) from quebracho were purified using affinity chromatography with sephadex LH-20 and used as a standard. Low concentrations of CT have been defined as 10 g kg-1 DM or less and medium as 10 to 40 g kg-1 DM, and levels exceeding 40 g kg-1 DM as high. Hybrid 9953130 had the highest concentration of CT among the sorghum silages (P 0.09). The highest CP content was noted for line CMSXS165 (97.4 gkg-1; P < 0.05). Concentrations of CP in CMSXS114 (83.2 g kg-1), BR 700 (76.4 g kg-1), BR701 (80.5 g kg-1), and AG2005 (79.2 g kg-1) were above the overall mean (74.0 g kg-1). The in vitro digestibilities (24 and 48 hours) of the two isogenics lines CMSXS114 (T) and CMSXS165 (WT) were not different. We concluded that the CT level did not affect digestibility; however, relative CT concentrations were low. Therefore, we could not suggest significant effects of CT content on DM intake, digestibility levels or performance in cattle fed with any of these sorghum silages

    Composição nutritiva de ingredientes para rações de aves.

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    bitstream/item/58402/1/CUsersPiazzonDocuments241.pdfAcesso em: 13 jun 2007
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