Soil Organic Matter and Root and Rhizome Responses to Management Strategies in Smooth Bromegrass Pastures

Soil organic matter (SOM) is a key component of pasture production. This is study investigated how management strategies that varied amount and form of N input in a long-term experiment affected concentrations and stocks of total-soil organic C and N, particulate organic carbon (POC), particulate organic nitrogen (PON), root and rhizome mass, C and N contents in topsoil of smooth bromegrass (Bromus inermis Leyss.) pastures with silty clay loam soils in a wet (2010) and dry (2012) year. Management strategies included: (i) unfertilized pasture grazed with unsupplemented beef cattle (CONT); (ii) unfertilized pasture grazed with dried distillers grains plus solubles (DDGS)-supplemented beef cattle (SUPP); and (iii) nitrogen-fertilized pasture grazed with unsupplemented beef cattle (FERT). After 8 yr, management strategies had similar concentrations and stocks of total-soil organic C and N, POC, and PON, and there were no management strategy × year interactions. From 2010 to 2012, total-soil organic C and N, POC, and PON stocks increased as soils dried and soil bulk density increased. The CONT and SUPP management strategies had less root and rhizome mass (concentrations and stocks) and greater soil bulk density than FERT. These belowground responses were consistent with earlier research conducted at the site demonstrating greater herbage accumulation and litter deposition in FERT. Management strategies that vary amount and form of N inputs into pasture appear to have low potential to affect total-soil organic C and N concentrations in the short-term, but long-term effects of less root and rhizome contents remain unknown

Litter Deposition and Nitrogen Return in Rotationally Stocked Smooth Bromegrass Pastures

Understanding how management systems impact nutrient cycling is important to pasture sustainability. From 2010 to 2011, we investigated how supplementation of beef cattle (Bos taurus) with corn (Zea mays L.) dried distillers grains plus solubles (DDGS) on unfertilized, rotationally stocked smooth bromegrass (Bromus inermis Leyss.) pasture (SUPP) affected the litter pool, residual herbage mass, litter deposition, and litter quality relative to unsupplemented beef cattle rotationally stocked on unfertilized control (CONT) and N-fertilized (FERT) smooth bromegrass pastures. As hypothesized based on management for greater herbage mass and animal demand during the grazing season, litter deposition was 48% greater in FERT than CONT and SUPP. Management effects, however, depended on year and rotation. Differences in the litter pool, residual herbage mass, and litter deposition typically were greatest before and after the third and fourth rotations, time periods coinciding with peak herbage mass. Meanwhile, deposited litter contained 16.5, 18.1, and 18.9 g N kg–1 and returned 27, 30, and 46 kg N ha–1 through the 158-d grazing season, equivalent to 35, 23, and 34% of total N returning through litter and excreta in CONT, SUPP, and FERT, respectively. Trampling during the 4- to 6-d grazing periods and senescence of herbage contributed to litter deposition. Increase of litter deposition and N return during the grazing season in FERT indicated this system may maintain better soil quality than CONT and SUPP. More research is necessary to examine how changes in litter deposition and N return affect litter decomposition, N losses, and soil organic matter dynamics

Soil Organic Matter and Root and Rhizome Responses to Management Strategies in Smooth Bromegrass Pastures

Soil organic matter (SOM) is a key component of pasture production. This is study investigated how management strategies that varied amount and form of N input in a long-term experiment affected concentrations and stocks of total-soil organic C and N, particulate organic carbon (POC), particulate organic nitrogen (PON), root and rhizome mass, C and N contents in topsoil of smooth bromegrass (Bromus inermis Leyss.) pastures with silty clay loam soils in a wet (2010) and dry (2012) year. Management strategies included: (i) unfertilized pasture grazed with unsupplemented beef cattle (CONT); (ii) unfertilized pasture grazed with dried distillers grains plus solubles (DDGS)-supplemented beef cattle (SUPP); and (iii) nitrogen-fertilized pasture grazed with unsupplemented beef cattle (FERT). After 8 yr, management strategies had similar concentrations and stocks of total-soil organic C and N, POC, and PON, and there were no management strategy × year interactions. From 2010 to 2012, total-soil organic C and N, POC, and PON stocks increased as soils dried and soil bulk density increased. The CONT and SUPP management strategies had less root and rhizome mass (concentrations and stocks) and greater soil bulk density than FERT. These belowground responses were consistent with earlier research conducted at the site demonstrating greater herbage accumulation and litter deposition in FERT. Management strategies that vary amount and form of N inputs into pasture appear to have low potential to affect total-soil organic C and N concentrations in the short-term, but long-term effects of less root and rhizome contents remain unknown

Litter Deposition and Nitrogen Return in Rotationally Stocked Smooth Bromegrass Pastures

Understanding how management systems impact nutrient cycling is important to pasture sustainability. From 2010 to 2011, we investigated how supplementation of beef cattle (Bos taurus) with corn (Zea mays L.) dried distillers grains plus solubles (DDGS) on unfertilized, rotationally stocked smooth bromegrass (Bromus inermis Leyss.) pasture (SUPP) affected the litter pool, residual herbage mass, litter deposition, and litter quality relative to unsupplemented beef cattle rotationally stocked on unfertilized control (CONT) and N-fertilized (FERT) smooth bromegrass pastures. As hypothesized based on management for greater herbage mass and animal demand during the grazing season, litter deposition was 48% greater in FERT than CONT and SUPP. Management effects, however, depended on year and rotation. Differences in the litter pool, residual herbage mass, and litter deposition typically were greatest before and after the third and fourth rotations, time periods coinciding with peak herbage mass. Meanwhile, deposited litter contained 16.5, 18.1, and 18.9 g N kg–1 and returned 27, 30, and 46 kg N ha–1 through the 158-d grazing season, equivalent to 35, 23, and 34% of total N returning through litter and excreta in CONT, SUPP, and FERT, respectively. Trampling during the 4- to 6-d grazing periods and senescence of herbage contributed to litter deposition. Increase of litter deposition and N return during the grazing season in FERT indicated this system may maintain better soil quality than CONT and SUPP. More research is necessary to examine how changes in litter deposition and N return affect litter decomposition, N losses, and soil organic matter dynamics

Tau protein, A beta 42 and S-100B protein in cerebrospinal fluid of patients with dementia with Lewy bodies

The intra vitam diagnosis of dementia with Lewy bodies (DLB) is still based on clinical grounds. So far no technical investigations have been available to support this diagnosis. As for tau protein and beta-amyloid((1-42)) (Abeta42), promising results for the diagnosis of Alzheimer's disease ( AD) have been reported; we evaluated these markers and S-100B protein in cerebrospinal fluid (CSF), using a set of commercially available assays, of 71 patients with DLB, 67 patients with AD and 41 nondemented controls (NDC) for their differential diagnostic relevance. Patients with DLB showed significantly lower tau protein values compared to AD but with a high overlap of values. More prominent differences were observed in the comparison of DLB patients with all three clinical core features and AD patients. Abeta42 levels were decreased in the DLB and AD groups versus NDC, without significant subgroup differences. S-100B levels were not significantly different between the groups. Tau protein levels in CSF may contribute to the clinical distinction between DLB and AD, but the value of the markers is still limited especially due to mixed pathology. We conclude that more specific markers have to be established for the differentiation of these diseases. Copyright (C) 2005 S. Karger AG, Basel

Large-scale distributions of mid- and far-infrared emission from the center to the halo of M82 revealed with AKARI

The edge-on starburst galaxy M82 exhibits complicated distributions of gaseous materials in its halo, which include ionized superwinds driven by nuclear starbursts, neutral materials entrained by the superwinds, and large-scale neutral streamers probably caused by a past tidal interaction with M81. We investigate detailed distributions of dust grains and polycyclic aromatic hydrocarbons (PAHs) around M82 to understand their interplay with the gaseous components. We performed mid- (MIR) and far-infrared (FIR) observations of M82 with the Infrared Camera and Far-Infrared Surveyor on board AKARI. We obtain new MIR and FIR images of M82, which reveal both faint extended emission in the halo and very bright emission in the center with signal dynamic ranges as large as five and three orders of magnitude for the MIR and FIR, respectively. We detect MIR and FIR emission in the regions far away from the disk of the galaxy, reflecting the presence of dust and PAHs in the halo of M82. We find that the dust and PAHs are contained in both ionized and neutral gas components, implying that they have been expelled into the halo of M82 by both starbursts and galaxy interaction. In particular, we obtain a tight correlation between the PAH and H$\alpha$ emission, which provides evidence that the PAHs are well mixed in the ionized superwind gas and outflowing from the disk.Comment: 12 pages, 8 figures, accepted for publication in A&

Volcanic and geochemical evolution of the Teno massif, Tenerife, Canary Islands: some repercussions of giant landslides on ocean island magmatism

Large-scale, catastrophic mass wasting is a major process contributing to the dismantling of oceanic intraplate volcanoes. Recent studies, however, have highlighted a possible feedback relationship between flank collapse, or incipient instability, and subsequent episodes of structural rearrangement and/or renewed volcano growth. The Teno massif, located in northwestern Tenerife (Canary Islands), is a deeply eroded Miocene shield volcano that was built in four major eruptive phases punctuated by two lateral collapses, each removing >20–25 km3 of the volcano's north flank. In this paper, we use detailed field observations and petrological and geochemical data to evaluate possible links between large-scale landslides and subsequent volcanism/magmatism during Teno's evolution. Inspection of key stratigraphic sequences reveals that steep angular unconformities, relics of paleolandslide scars, are marked by polymict breccias. Near their base, these deposits typically include abundant juvenile pyroclastic material, otherwise scarce in the region. While some of Teno's most evolved, low-density magmas were produced just before flank collapses, early postlandslide lava sequences are characterized by anomalously high proportions of dense ankaramite flows, extremely rich in clinopyroxene and olivine crystals. A detailed sampling profile shows transitions from low-Mg # lavas relatively rich in SiO2 to lavas with low silica content and comparatively high Mg # after both landslides. Long-term variations in Zr/Nb, normative nepheline, and La/Lu are coupled but do not show a systematic correlation with stratigraphic boundaries. We propose that whereas loading of the growing precollapse volcano promoted magma stagnation and differentiation, the successive giant landslides modified the shallow volcano-tectonic stress field at Teno, resulting in widespread pyroclastic eruptions and shallow magma reservoir drainage. This rapid unloading of several tens of km3 of near-surface rocks appears to have upset magma differentiation processes, while facilitating the remobilization and tapping of denser ankaramite magmas that were stored in the uppermost mantle. Degrees of mantle melting coincidently reached a maximum in the short time interval between the two landslides and declined shortly after, probably reflecting intrinsic plume processes rather than a collapse-induced influence on mantle melting. Our study of Teno volcano bears implications for other oceanic volcanoes where short-term compositional variations may also directly relate to major flank collapse events

Novel role for the innate immune receptor toll-like receptor 4 (TLR4) in the regulation of the wnt signaling pathway and photoreceptor apoptosis

Recent evidence has implicated innate immunity in regulating neuronal survival in the brain during stroke and other neurodegenerations. Photoreceptors are specialized light-detecting neurons in the retina that are essential for vision. In this study, we investigated the role of the innate immunity receptor TLR4 in photoreceptors. TLR4 activation by lipopolysaccharide (LPS) significantly reduced the survival of cultured mouse photoreceptors exposed to oxidative stress. With respect to mechanism, TLR4 suppressed Wnt signaling, decreased phosphorylation and activation of the Wnt receptor LRP6, and blocked the protective effect of the Wnt3a ligand. Paradoxically, TLR4 activation prior to oxidative injury protected photoreceptors, in a phenomenon known as preconditioning. Expression of TNFα and its receptors TNFR1 and TNFR2 decreased during preconditioning, and preconditioning was mimicked by TNFα antagonists, but was independent of Wnt signaling. Therefore, TLR4 is a novel regulator of photoreceptor survival that acts through the Wnt and TNFα pathways. © 2012 Yi et al