Purchasing E-books: Considerations and Models for the Smaller Academic Library

There are many decisions to consider when acquiring e-books for the small academic library. This article lists some preparatory questions to be settled regarding format, vendor, and type of acquisition, and describes the main purchase models currently being used to acquire e-books. Cataloging issues are also discussed

Study of acoustic emission during mechanical tests of large flight weight tank structure

A polyphenylane oxide insulated, flight weight, subscale, aluminum tank was monitored for acoustic emissions during a proof test and during 100 cycles of environmental test simulating space flights. The use of a combination of frequency filtering and appropriate spatial filtering to reduce background noise was found to be sufficient to detect acoustic emission signals of relatively small intensity expected from subcritical crack growth in the structure. Several emission source locations were identified, including the one where a flaw was detected by post-test X-ray inspections. For most source locations, however, post-test inspections did not detect flaws; this was partially attributed to the higher sensitivity of the acoustic emission technique than any other currently available NDT method for detecting flaws

Will whole-tree harvest of jack pine (pinus banksiana) deplete soil nutrients in low-productivity, sand soil?

In 2009 and 2010 a study was conducted to determine if whole-tree harvest (WTH) would deplete the soil nutrients in Rubicon soil. The specific objectives of the study were: 1) Estimation of biomass and nutrient content of above- and below-ground tree components in mature jack pine (Pinus banksiana) stands growing on a coarse-textured, low-productivity soil, 2) Determination of total C and N and exchangeable soil cations and other physical properties in mature jack pine stands, and 3) Comparison of the possible impacts of CH and WTH on subsequent soil nutrient pools. In total, four even aged jack pine stands on Rubicon soil were studied. Allometric equations were used to determine aboveground biomass and nutrients, and soil samples from each stand were analyzed for total C and N, exchangeable Ca, K, and Mg, pH, organic matter content, texture, and available water holding capacity. Results indicate that WTH will leave enough nutrients on-site for the next rotation of trees, but the potential for increased decomposition and leaching may still result in nutrient loss, especially in these coarse-textured soils with low mineral soil organic matter

Fire and Grazing Influences on Rates of Riparian Woody Plant Expansion along Grassland Streams.

Citation: Veach AM, Dodds WK, Skibbe A (2014) Fire and Grazing Influences on Rates of Riparian Woody Plant Expansion along Grassland Streams. PLoS ONE 9(9): e106922. doi:10.1371/journal.pone.0106922Grasslands are threatened globally due to the expansion of woody plants. The few remaining headwater streams within tallgrass prairies are becoming more like typical forested streams due to rapid conversion of riparian zones from grassy to wooded. Forestation can alter stream hydrology and biogeochemistry. We estimated the rate of riparian woody plant expansion within a 30 m buffer zone surrounding the stream bed across whole watersheds at Konza Prairie Biological Station over 25 years from aerial photographs. Watersheds varied with respect to experimentally-controlled fire and bison grazing. Fire frequency, presence or absence of grazing bison, and the historical presence of woody vegetation prior to the study time period (a proxy for proximity of propagule sources) were used as independent variables to predict the rate of riparian woody plant expansion between 1985 and 2010. Water yield was estimated across these years for a subset of watersheds. Riparian woody encroachment rates increased as burning became less frequent than every two years. However, a higher fire frequency (1–2 years) did not reverse riparian woody encroachment regardless of whether woody vegetation was present or not before burning regimes were initiated. Although riparian woody vegetation cover increased over time, annual total precipitation and average annual temperature were variable. So, water yield over 4 watersheds under differing burn frequencies was quite variable and with no statistically significant detected temporal trends. Overall, burning regimes with a frequency of every 1–2 years will slow the conversion of tallgrass prairie stream ecosystems to forested ones, yet over long time periods, riparian woody plant encroachment may not be prevented by fire alone, regardless of fire frequency

Threats from urban expansion, agricultural transformation and forest loss on global conservation priority areas

Including threats in spatial conservation prioritization helps identify areas for conservation actions where biodiversity is at imminent risk of extinction. At the global level, an important limitation when identifying spatial priorities for conservation actions is the lack of information on the spatial distribution of threats. Here, we identify spatial conservation priorities under three prominent threats to biodiversity (residential and commercial development, agricultural expansion, and forest loss), which are primary drivers of habitat loss and threaten the persistence of the highest number of species in the International Union for the Conservation of Nature (IUCN) Red List, and for which spatial data is available. We first explore how global priority areas for the conservation of vertebrate (mammals, birds, and amphibians) species coded in the Red List as vulnerable to each threat differ spatially. We then identify spatial conservation priorities for all species vulnerable to all threats. Finally, we identify the potentially most threatened areas by overlapping the identified priority areas for conservation with maps for each threat. We repeat the same with four other well-known global conservation priority area schemes, namely Key Biodiversity Areas, Biodiversity Hotspots, the global Protected Area Network, and Wilderness Areas. We find that residential and commercial development directly threatens only about 4% of the global top 17% priority areas for species vulnerable under this threat. However, 50% of the high priority areas for species vulnerable to forest loss overlap with areas that have already experienced some forest loss. Agricultural expansion overlapped with similar to 20% of high priority areas. Biodiversity Hotspots had the greatest proportion of their total area under direct threat from all threats, while expansion of low intensity agriculture was found to pose an imminent threat to Wilderness Areas under future agricultural expansion. Our results identify areas where limited resources should be allocated to mitigate risks to vertebrate species from habitat loss.Peer reviewe