655 research outputs found
Exploitation promotes earlier sex change in a protandrous patellid limpet, Patella aspera Röding, 1798
Exploitation of organisms can prompt the reduction in the number and size of target populations consequently affecting reproductive output and replenishment. Here, we investigated the effects of exploitation on the population structure of a protandrous patellid limpet, Patella aspera, an overexploited Macaronesian endemic. Timed dives were used to collect animals across eleven islands of Macaronesia. Individuals were inspected for sex, size, and gonad stage. Using catch effort (time per person) per island coastal perimeter as a surrogate for exploitation intensity, we found that limpet abundance (CPUE) and mean size tended to decrease with exploitation intensity. When considering the sex of animals separately, the size of the largest male, but not females, decreased with exploitation. In contrast, the size of the smallest male remained relatively consistent, whereas the size of the smallest female decreased significantly with exploitation. As exploitation is mostly targeting larger individuals, results suggest that males are compensating the removal of larger females, by undergoing sex change at smaller and presumably earlier sizes. These results have wider implications for the conservation of P. aspera, as a reduction in female size will likely affect the numbers of oocytes produced, hence fecundity. Regulations promoting the protection of the larger-sized animals should be enforced to safeguard the replenishment of the population
The changing carbon cycle of the coastal ocean
The carbon cycle of the coastal ocean is a dynamic component of the global carbon budget. But the diverse sources and sinks of carbon and their complex interactions in these waters remain poorly understood. Here we discuss the sources, exchanges and fates of carbon in the coastal ocean and how anthropogenic activities have altered the carbon cycle. Recent evidence suggests that the coastal ocean may have become a net sink for atmospheric carbon dioxide during post-industrial times. Continued human pressures in coastal zones will probably have an important impact on the future evolution of the coastal ocean's carbon budget
Hemifacial spasm in a patient with neurofibromatosis and Arnold-Chiari malformation: a unique case association
A novel in situ passive heating method for evaluating whole-tree responses to daytime warming in remote environments
Background
Many significant ecosystems, including important non-forest woody ecosystems such as the Cerrado (Brazilian savannah), are under threat from climate change, yet our understanding of how increasing temperatures will impact native vegetation remains limited. Temperature manipulation experiments are important tools for investigating such impacts, but are often constrained by access to power supply and limited to low-stature species, juvenile individuals, or heating of target organs, perhaps not fully revealing how entire or mature individuals and ecosystems will react to higher temperatures.
Results
We present a novel, modified open top chamber design for in situ passive heating of whole individuals up to 2.5 m tall (but easily expandable) in remote field environments with strong solar irradiance. We built multiple whole-tree heating structures (WTHSs) in an area of Cerrado around native woody species Davilla elliptica and Erythroxylum suberosum to test the design and its effects on air temperature and humidity, while also studying the physiological responses of E. suberosum to short-term heating. The WTHSs raised internal air temperature by approximately 2.5 °C above ambient during the daytime. This increased to 3.4 °C between 09:00 and 17:00 local time when thermal impact was greatest, and during which time mean internal temperatures corresponded closely with maximum ambient temperatures. Heating was consistent over time and across WTHSs of variable size and shape, and they had minimal effect on humidity. E. suberosum showed no detectable response of photosynthesis or respiration to short-term experimental heating, but some indication of acclimation to natural temperature changes.
Conclusions
Our WTHSs produced a consistent and reproducible level of daytime heating in line with mid-range climate predictions for the Cerrado biome by the end of the century. The whole-tree in situ passive heating design is flexible, low-cost, simple to build using commonly available materials, and minimises negative impacts associated with passive chambers. It could be employed to investigate the high temperature responses of many understudied species in a range of complex non-forest environments with sufficient solar irradiance, providing new and important insights into the possible impacts of our changing climate
LILRA2 Selectively Modulates LPS-Mediated Cytokine Production and Inhibits Phagocytosis by Monocytes
The activating immunoglobulin-like receptor, subfamily A, member 2 (LILRA2) is primarily expressed on the surface of cells of the innate immunity including monocytes, macrophages, neutrophils, basophils and eosinophils but not on lymphocytes and NK cells. LILRA2 cross-linking on monocytes induces pro-inflammatory cytokines while inhibiting dendritic cell differentiation and antigen presentation. A similar activating receptor, LILRA4, has been shown to modulate functions of TLR7/9 in dendritic cells. These suggest a selective immune regulatory role for LILRAs during innate immune responses. However, whether LILRA2 has functions distinct from other receptors of the innate immunity including Toll-like receptor (TLR) 4 and FcγRI remains unknown. Moreover, the effects of LILRA2 on TLR4 and FcγRI-mediated monocyte functions are not elucidated. Here, we show activation of monocytes via LILRA2 cross-linking selectively increased GM-CSF production but failed to induce IL-12 and MCP-1 production that were strongly up-regulated by LPS, suggesting functions distinct from TLR4. Interestingly, LILRA2 cross-linking on monocytes induced similar amounts of IL-6, IL-8, G-CSF and MIP-1α but lower levels of TNFα, IL-1β, IL-10 and IFNγ compared to those stimulated with LPS. Furthermore, cross-linking of LILRA2 on monocytes significantly decreased phagocytosis of IgG-coated micro-beads and serum opsonized Escherichia coli but had limited effect on phagocytosis of non-opsonized bacteria. Simultaneous co-stimulation of monocytes through LILRA2 and LPS or sequential activation of monocytes through LILRA2 followed by LPS led lower levels of TNFα, IL-1β and IL-12 production compared to LPS alone, but had additive effect on levels of IL-10 and IFNγ but not on IL-6. Interestingly, LILRA2 cross-linking on monocytes caused significant inhibition of TLR4 mRNA and protein, suggesting LILRA2-mediated suppression of LPS responses might be partly via regulation of this receptor. Taken together, we provide evidence that LILRA2-mediated activation of monocytes is significantly different to LPS and that LILRA2 selectively modulates LPS-mediated monocyte activation and FcγRI-dependent phagocytosis
Implementation of GIS-Based Applications in Water Governance
__Abstract__
Geographical Information Systems (GIS) are computer programs that are able to
bring large amounts of data of both the physical and the social system together in one
comprehensive overview shown digitally. GIS occurred very rapidly on the Dutch policy
agenda. In this paper we analyze how the fast introduction process of GIS-based
instruments in water management and more specifically in river flood management can
be explained. By applying a range of classical models on agenda-setting, we show the
important contribution of GIS to the water and flood issue in current spatial planning and
policy development in the Netherland
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