scholarly journals Long‐term monitoring of a highly invaded annual grassland community through drought, before and after an unintentional fire

2020 ◽  
Vol 31 (2) ◽  
pp. 307-318
Author(s):  
Diane M. Thomson ◽  
Adin D. Bonapart ◽  
Rachel A. King ◽  
Emily L. Schultz ◽  
Charlotte R. Startin



2012 ◽  
Vol 538-541 ◽  
pp. 1808-1811
Author(s):  
Zdeněk Šnirch

Paper deal with influence of on service life and degradation processes at construction of bridge piers and abutments before and after repair actions. Monitored dependencies are then reflect on degradation curves each for a singles construction characteristics (compression strength of concrete, degradation of surface, volume of carbonatation etc.) Pursuant to long-term monitoring of records from bridge piers surface diagnostic we have to be able to unite the records and use them for silicate coatings degradation dependence on bridge piers and abutments and laboratory simulated degradation.



Author(s):  
Elyas Ghafoori ◽  
Ardalan Hosseini ◽  
Riadh Al-Mahaidi ◽  
Xiao-Ling Zhao ◽  
Masoud Motavalli ◽  
...  

<p>This study gives an overview on carbon fibre-reinforced polymer (CFRP) strengthening and wireless sensor network (WSN) monitoring of a 121-year-old metallic roadway bridge in Melbourne, Australia. A flat prestressed unbonded retrofit (FPUR) system was developed to apply prestressed CFRP plates to the steel cross-girders of Diamond-Creek Bridge. The bridge is subjected to daily passenger and heavy truck vehicles. Sets of laboratory tests were performed to examine the efficiency and fatigue performance of the proposed FPUR system, prior to its installation on the bridge. Furthermore, in order to demonstrate the efficiency of the proposed retrofit technique, the bridge was instrumented with different types of sensors (including strain gauges, temperature and humidity sensors), and short- and long-term measurements were performed. As for short-term measurements, the bridge was loaded by a 42.5-tonne semi-trailer before and after strengthening. For the long-term monitoring, a WSN system was used to monitor the prestress level in the CFRP reinforcements for at least one year. The CFRP plates were prestressed up to about 980 MPa (38% of the CFRP ultimate strength), which resulted in about 50% reduction in the maximum tensile stress in the bottom flanges of the strengthened I-girders. The results of the short- and long-term measurements in this study showed that the proposed FPUR system can be very effective for flexural and fatigue strengthening of such bridge girders.</p>



2000 ◽  
Vol 17 (1) ◽  
pp. 72-82 ◽  
Author(s):  
B. M. Gaensler ◽  
R. W. Hunstead

AbstractBefore and after every 12 hour synthesis observation, the Molonglo Observatory Synthesis Telescope (MOST) measures the flux densities of ∼5 compact extragalactic radio sources, chosen from a list of 55 calibrators. From 1984 to 1996, the MOST made some 58,000 such measurements. We have developed an algorithm to process this dataset to produce a light curve for each source spanning this thirteen-year period. We find that 18 of the 55 calibrators are variable, on time scales between one and ten years. There is the tendency for sources closer to the Galactic Plane to be more likely to vary, which suggests that the variability is a result of refractive scintillation in the Galactic interstellar medium. The sources with the flattest radio spectra show the highest levels of variability, an effect possibly resulting from differing orientations of the radio axes to the line of sight.



2001 ◽  
Vol 58 (9) ◽  
pp. 1773-1781 ◽  
Author(s):  
Stephen C Schroeter ◽  
Daniel C Reed ◽  
David J Kushner ◽  
James A Estes ◽  
David S Ono

Management of sustainable fisheries depends upon reliable estimates of stock assessment. Assessment of many stocks is based entirely on fishery-dependent data (e.g., catch per unit effort), which can be problematic. Here we use fishery-independent data on stock size, collected within and outside of no-take reserves before and after the onset of fishing, to evaluate the status of the dive fishery for warty sea cucumbers, Parastichopus parvimensis, in southern California. Long-term monitoring data showed that abundance decreased throughout the Channel Islands within 3–6 years after the onset of fishing. No significant changes in the abundance of P. parvimensis were observed at the two non-fished reserve sites, although densities tended to increase following onset of the fishery. Before–after, control–impact (BACI) analyses of seven fished and two non-fished sites implicated fishing mortality as the cause of 33–83% stock declines. In sharp contrast, stock assessment based on CPUE data showed no declines and a significant increase at one island. To date, most discussion on marine reserves has focused on the protection and enhancement of exploited populations. Our study demonstrates the critically important, but often overlooked, role that marine reserves can play in providing reliable information on stock assessment.



PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3942 ◽  
Author(s):  
Barbara Maria Smith ◽  
Anita Diaz ◽  
Linton Winder

Habitat restoration projects are often conducted when prior use or extraction of natural resources results in land degradation. The success of restoration programmes, however, is variable, and studies that provide evidence of long term outcomes are valuable for evaluation purposes. This study focused on the restoration of vegetation within a limestone quarry in Dorset, UK between 1997 and 2014. Using a randomised block design, the effect of seed mix and seed rate on the development of community assemblage was investigated in comparison to a nearby target calcareous grassland site. We hypothesised that seed mix composition and sowing rate would influence both the trajectory of the grassland assemblage and final community composition. We found that species composition (in relation to both richness and community assemblage) was strongly influenced by time and to some extent by seed rate and seed mix. However, no treatments achieved strong resemblance to the calcareous grassland target vegetation; rather they resembled mesotrophic communities. We conclude that (as with previous studies) there is no “quick fix” for the establishment of a grassland community; long-term monitoring provides useful information on the trajectory of community development; sowing gets you something (in our case mesotrophic grassland), but, it may not be the target vegetation (e.g., calcicolous grassland) you want that is difficult to establish and regenerate; it is important to sow a diverse mix as subsequent recruitment opportunities are probably limited; post-establishment management should be explored further and carefully considered as part of a restoration project.



2020 ◽  
pp. 194589242095396 ◽  
Author(s):  
Giuseppe Brescia ◽  
Giacomo Contro ◽  
Luciano Giacomelli ◽  
Umberto Barion ◽  
Anna Chiara Frigo ◽  
...  

Background Very few studies have compared blood eosinophil and basophil levels before and after surgery in patients with eosinophilic CRSwNP (eCRSwNP). No investigations seem to have repeatedly measured them pre- and postoperatively in eCRSwNP patients with recurring versus non-recurring disease to examine how their levels evolved. Objective Hence this study to analyze blood eosinophil and basophil levels in patients with eCRSwNP immediately before surgery and afterwards, at 4 months, 1 year, and then yearly up to 5 years. Methods Fifty-one eCRSwNP patients were enrolled, who all had preoperative laboratory data and the results of at least 4 of the 6 scheduled postoperative follow-up tests. Results Seventeen patients had recurrent disease. Blood eosinophil counts (p = 0.005) and percentages (p = 0.002) were both higher in these patients than in those whose eCRSwNPs did not recur after surgery. Blood basophil counts (p = 0.04) and percentages (p < 0.05) were also significantly higher in patients whose eCRSwNPs relapsed. The time by relapse interaction was not significant for either counts or percentages, though an effect of time was detected for basophil counts (p = 0.01). Conclusions In eCRSwNP, the statistical analysis of repeated quantitative laboratory data can shed light on the evolution of a patient’s systemic inflammatory picture in response to previous treatments, and above all to long-term therapies. Long-term monitoring of blood eosinophil and basophil levels could be of significant value when monoclonal antibodies that inhibit IL signaling will widely enter in clinical practice for eCRSwNP treatment to follow the effectiveness of therapy over time.





Author(s):  
Barbara S. Minsker ◽  
Charles Davis ◽  
David Dougherty ◽  
Gus Williams


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