Fungal Succession During the Decomposition of Ectomycorrhizal Fine Roots.

Ectomycorrhizal (ECM) fine roots account for a substantial proportion of forest production and their decomposition releases large amounts of nutrients to the soil ecosystem. However, little is known about the fungi involved in ECM decomposition, including assemblages of fungal saprotrophs, endophytes, and the ECM fungi themselves. To follow fungal succession during the degradation of senescing fine roots, understory seedlings of Abies balsamea and Picea rubens at two sites in the Acadian forest of Nova Scotia were either severed at the root collar or left as controls. Root systems were collected sequentially over two growing seasons and assessed for fine root loss and ECM mantle integrity. ECM were identified by ITS-PCR and grouped into broad morphological categories. Fungal communities colonizing the senescing fine roots were also monitored by systematically constructing clone libraries over the course of the experiment. ECM with cottony, weakly pigmented mantles (e.g., Cortinarius) degraded within the first year. Those with cottony, but intensely pigmented mantles (Piloderma), and smooth mantles with weak pigmentation (Russulaceae) degraded more slowly. Smooth, melanized ECM (Cenococcum and Tomentella) generally maintained integrity over the course of the experiment. Rates of fine root loss and changes in ECM mantle integrity were positively correlated with soil temperature. ECM DNA was detected throughout the experiment, and was not replaced by that of saprotrophic species during the two seasons sampled. However, fungal root endophytes (e.g., Helotiaceae) initially increased in abundance and then decreased as mantles degraded, suggesting a possible role in ECM decomposition.

Data on vegetation across forest edges from the FERN (Forest Edge Research Network).

Many studies have focused on vegetation across forest edges to study impacts of edges created by human activities on forest structure and composition, or patterns of vegetation at inherent natural edges. Our objective was to create a database of plant-related variables across different types of edges from various studies (mainly from across Canada, but also in Brazil and Belize) to facilitate edge research. We compiled data on vegetation along more than 300 transects perpendicular to forest edges adjacent to clear-cuts, burned areas, bogs, lakes, barrens, insect disturbances, and riparian areas from 24 studies conducted over the past three decades. Data were compiled for more than 400 plant species and forest structure variables (e.g., trees, logs, canopy cover). All data were collected with a similar sampling design of quadrats along transects perpendicular to forest edges, but with varying numbers of transects and quadrats, and distances from the edge. The purpose for most of the studies was either to determine the distance of edge influence (edge width) or to explore the pattern of vegetation along the edge to interior gradient. We provide data tables for the cover of plant species and functional groups, the species and size of live and dead trees, the density of saplings, maximum height of functional groups and shrub species, and the cover of functional groups at different heights (vertical distribution of vegetation). The Forest Edge Research Network (FERN) database provides extensive data on many variables that can be used for further study including meta-analyses and can assist in answering questions important to conservation efforts (e.g., how is distance of edge influence from created edges affected by different factors?). We plan to expand this database with subsequent studies from the authors and we invite others to contribute to make this a more global database. The data are released under a CC0 license. When using these data, we ask that you cite this data paper and any relevant publications listed in our metadata file. We also encourage you to contact the first author if you are planning to use or contribute to this database.

Delayed hydrocephalus after excision of a colloid cyst: a case report.

BACKGROUND: In this case report we describe an unusual case of a patient who underwent resection of a colloid cyst and then presented 6 weeks postoperatively with obstructive hydrocephalus. There appear to be no prior reports of such a delayed complication after colloid cyst resection. CASE PRESENTATION: A 50-year-old Caucasian woman underwent resection of a colloid cyst with an uncomplicated perioperative course. Postoperative imaging demonstrated complete resection of the cyst. She was discharged home on postoperative day 4 but presented 6 weeks later with symptoms of obstructive hydrocephalus resulting in poor neurologic outcome and ultimately death. CONCLUSION: Patients presenting with symptoms of hydrocephalus after resection of a colloid cyst should be followed closely, and timely placement of an external ventricular drain may be critical.

Evaluation of the Simpson's Method to Determine Left Ventricular Ejection Fraction Using the Transgastric Two-Chamber View.

INTRODUCTION: Left ventricular chamber size and functional assessment by transesophageal echocardiography can be difficult if visualization is poor in the mid-esophageal views. However, the accuracy of using the Simpson's method in the transgastric 2-chamber (TG2C) as an alternative approach has not been assessed. METHODS: The Simpson's method was performed by 2 independent reviewers using midesophageal 2-chamber (ME2C) and TG2C views. Echocardiographic images were retrieved retrospectively for 49 adult cardiac surgical patients. RESULTS: Two-way random effects intraclass correlation coefficients demonstrated no significant interobserver variability. Linear mixed effects models showed no significant differences in ME2C and TG2C measurements with regard to EDV (P=.4407), ESV (P=.5113), or EF (P=.0610).Compared to the ME2C view, the TG2C view had better image quality of the LV walls (image quality score median [interquartile range]: 2.00 [.00] vs 1.00 [1.00]; P<.0001), but worse image quality of the mitral annulus (1.00 [1.00] vs 2.00 [.00]; P<.0001) and LV apex (.00 [1.00] vs 2.00 [1.00]; P<.0001). CONCLUSIONS: This study suggests the Simpson's method can be applied to the TG2C view as an alternative to the standard midesophageal method to estimate chamber volumes and EF.