Can forest management based on natural disturbances maintain ecological resilience?

Given the increasingly global stresses on forests, many ecologists argue that managers must maintain ecological resilience: the capacity of ecosystems to absorb disturbances without undergoing fundamental change. In this review we ask: Can the emerging paradigm of natural-disturbance-based management (NDBM) maintain ecological resilience in managed forests? Applying resilience theory requires careful articulation of the ecosystem state under consideration, the disturbances and stresses that affect the persistence of possible alternative states, and the spatial and temporal scales of management relevance. Implementing NDBM while maintaining resilience means recognizing that (i) biodiversity is important for long-term ecosystem persistence, (ii) natural disturbances play a critical role as a generator of structural and compositional heterogeneity at multiple scales, and (iii) traditional management tends to produce forests more homogeneous than those disturbed naturally and increases the likelihood of unexpected catastrophic change by constraining variation of key environmental processes. NDBM may maintain resilience if silvicultural strategies retain the structures and processes that perpetuate desired states while reducing those that enhance resilience of undesirable states. Such strategies require an understanding of harvesting impacts on slow ecosystem processes, such as seed-bank or nutrient dynamics, which in the long term can lead to ecological surprises by altering the forest's capacity to reorganize after disturbance

Opportunities and challenges of China’s inquiry-based education reform in middle and high schools: Perspectives of science teachers and teacher educators

Consistent with international trends, an emergent interest in inquiry-based science teaching and learning in K-12 schools is also occurring in China. This study investigates the possibilities for and the barriers to enactment of inquiry-based science education in Chinese schools. Altogether 220 Chinese science teachers, science teacher educators and researchers (primarily from the field of chemistry education) participated in this study in August 2001. Participants represented 13 cities and provinces in China. We administered two questionnaires, one preceding and one following a 3-hour presentation by a US science educator and researcher about inquiry-based teaching and learning theories and practices. In each of three sites in which the study was conducted (Shanghai, Guangzhou and Beijing), questionnaires were administered, and four representative participants were interviewed. Our coding and analysis of quantifiable questionnaire responses (using a Likert scale), of open-ended responses, and of interview transcripts revealed enthusiastic interest in incorporating inquiry-based teaching and learning approaches in Chinese schools. However, Chinese educators face several challenges: (a) the national college entrance exam needs to align with the goals of inquiry-based teaching; (b) systemic reform needs to happen in order for inquiry-based science to be beneficial to students, including a change in the curriculum, curriculum materials, relevant resources, and teacher professional development; (c) class size needs to be reduced; and (d) an equitable distribution of resources in urban and rural schools needs to occur.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42933/1/10763_2005_Article_1517.pd

Transgenic overexpression of granulocyte macrophage-colony stimulating factor in the lung prevents hyperoxic lung injury.

Granulocyte macrophage-colony stimulating factor (GM-CSF) plays an important role in pulmonary homeostasis, with effects on both alveolar macrophages and alveolar epithelial cells. We hypothesized that overexpression of GM-CSF in the lung would protect mice from hyperoxic lung injury by limiting alveolar epithelial cell injury. Wild-type C57BL/6 mice and mutant mice in which GM-CSF was overexpressed in the lung under control of the SP-C promoter (SP-C-GM mice) were placed in >95% oxygen. Within 6 days, 100% of the wild-type mice had died, while 70% of the SP-C-GM mice remained alive after 10 days in hyperoxia. Histological assessment of the lungs at day 4 revealed less disruption of the alveolar wall in SP-C-GM mice compared to wild-type mice. The concentration of albumin in bronchoalveolar lavage fluid after 4 days in hyperoxia was significantly lower in SP-C-GM mice than in wild-type mice, indicating preservation of alveolar epithelial barrier properties in the SP-C-GM mice. Alveolar fluid clearance was preserved in SP-C-GM mice in hyperoxia, but decreased significantly in hyperoxia-exposed wild-type mice. Staining of lung tissue for caspase 3 demonstrated increased apoptosis in alveolar wall cells in wild-type mice in hyperoxia compared to mice in room air. In contrast, SP-C-GM mice exposed to hyperoxia demonstrated only modest increase in alveolar wall apoptosis compared to room air. Systemic treatment with GM-CSF (9 micro g/kg/day) during 4 days of hyperoxic exposure resulted in decreased apoptosis in the lungs compared to placebo. In studies using isolated murine type II alveolar epithelial cells, treatment with GM-CSF greatly reduced apoptosis in response to suspension culture. In conclusion, overexpression of GM-CSF enhances survival of mice in hyperoxia; this effect may be explained by preservation of alveolar epithelial barrier function and fluid clearance, at least in part because of reduction in hyperoxia-induced apoptosis of cells in the alveolar wall

Identification of a Distinct Lipidomic Profile in the Osteoarthritic Synovial Membrane by Mass Spectrometry Imaging

[Abstract] Objective: Synovial inflammation is one of the most characteristic events in different types of arthritis, including Osteoarthritis (OA). Emerging evidence also suggests the involvement of lipids in the regulation of inflammatory processes. The aim of this study was to elucidate the heterogeneity and spatial distribution of lipids in the OA synovial membrane and explore their putative involvement in inflammation. Method: The abundance and distribution of lipids were examined in human synovial membranes. To this end, histological cuts from this tissue were analysed by matrix-assisted laser desorption ionization - mass spectrometry imaging (MALDI-MSI). The lipidomic profile of OA synovium was characterized and compared with healthy and other forms of inflammatory arthropathies as Rheumatoid Arthritis (RA) and Psoriatic Arthritis (PsA) using principal component analysis and discriminant analysis methods. Lipid identification was undertaken by tandem MS analyses and database queries. Results: Our results reveal differential and characteristic lipidomic profiles between OA and control samples. Specifically, we unveiled that OA synovium presents elevated levels of phosphatidylcholines, fatty acids and lysophosphatidic acids and lower levels of lysophosphatidylcholines compared to control tissues. The spatial distribution of particular glycerophospholipids was also correlated with hypertrophic, inflamed or vascularized synovial areas. Compared with other inflammatory arthritis, the OA tissue showed lower amounts of phosphatidylethanolamine-based plasmalogens. Conclusions: This study provides a novel insight into the lipid profiles of synovial membrane and differences in abundance between OA and control tissues. The lipidomic alterations improves understanding of the pathogenic mechanisms of OA and may be important for its diagnosis.This work is supported by grants from Fondo Investigación Sanitaria-Spain (PI16/02124, PI17/00404 PI19/01206 and RETIC-RIER-RD16/0012/0002), integrated in the National Plan for Scientific Program, Development and Technological Innovation 2013–2016 and funded by the ISCIII-General Subdirection of Assessment and Promotion of Research – European Regional Development Fund (FEDER) “A way of making Europe”. This study is also supported by AE CICA-INIBIC (ED431E 2018/03) and grants IN607A2017/11 and IN607D2020/10 from Xunta de Galicia. The Biomedical Research Networking Center (CIBER) is an initiative from Instituto de Salud Carlos III (ISCIII). The Proteomics Unit of GIR belongs to ProteoRed, PRB3- ISCIII (PT17/0019/0014). B.R. has been supported by Xunta de Galicia (IN606B-2016/004). The research was partially performed within the M4I research program, financially supported by the Dutch Province of Limburg as part of the “LINK” programXunta de Galicia; ED431E 2018/03Xunta de Galicia; IN607A2017/11Xunta de Galicia; IN607D2020/10Xunta de Galicia; IN606B-2016/00