Biomass and composition of the understory vegetation in some Alnus rubra stands in western Oregon

The biomass and the composition of 15 stands of red alder (Alnus rubra Bong.) on river bottom sites in western Oregon was measured during August and early September, 1969. These stands ranged in age from two to 64 years. Biomass was found to vary from 134 k/ha (kilograms per hectare) for the very youngest stand to 7700 k/ha in one of the older stands. Net productivity for the first 64 years was estimated as 97 k/ha per year. Understory biomass was found to be a very small portion, up to Z. 5%, of the biomass of the alder overstory for similar stands. Composition was found to vary considerably as age of the overstory increased. Succession from a. grass-herb dominated understory to a shrub-fern dominated understory was quantified. The findings appear to support an earlier prediction that lands now dominated by reda1der may be dominated by brush fie1ds of Rubus spectailis in the future n the absence of a suitable conifer seed source

Composition, distribution and succession of subalpine meadows in Mount Rainier National Park

In 1970 a phytosociological reconnaissance consisting of 135 plots in the Subalpine Meadow Zone was made. These samples were sorted using an association table and several Alpine Zone and very early seral communities were set aside, An additional hundred plots taken by M. J. Hamann were incorporated with these and compiled in another association table and combined in a two-dimensional ordination. This analysis yielded 18 major and 16 minor described community types which were clustered into five vegetation types. A key to the vegetation and community types is also presented. Soil moisture and temperature data were taken during 1971 and 1972 and are used to help characterize selected important communities. Soil moistures did not drop much during either season, although differences between communities are apparent. The difference in temperatures (of the top 2 cm of soil) of the same selected communities were more striking. The Festuca dominated communities experienced soil temperatures over 35° C, while maximum temperatures in other communities rarely ranged over 20° C. Low night-time temperatures were relatively similar from community to community, ranging from near freezing to about + 5° C. Several successional patterns were uncovered. In general the communities in the Low-Herbaceous Vegetation Type are early seral and are replaced by members of the Wet-Sedge, Lush-Herbaceous and the Dry-Grass Vegetation Types. Trees appear to be invading all vegetation types variation in pattern and frequency. This variation is attributed to differences in soil moisture and temperature and depth and duration of winter snowpack. Analysis of the ages of invading trees indicates that there was an intensive invasion in the early 1930's and several other minor invasion periods Several factors are discussed which must be favorable for the successful invasion of meadows by trees. The Subalpine Meadow Zone, using vegetation types as map units, is mapped at a scale of about 1:50,000 The total area of the meadow vegetation in the zone is 14,650 acres (6,000 hectares). The entire zone including open subalpine woods covers 24,650 acres (10,000 hectares)

Deconvoluting heme biosynthesis to target blood-stage malaria parasites

Heme metabolism is central to blood-stage infection by the malaria parasite Plasmodium falciparum. Parasites retain a heme biosynthesis pathway but do not require its activity during infection of heme-rich erythrocytes, where they can scavenge host heme to meet metabolic needs. Nevertheless, heme biosynthesis in parasite-infected erythrocytes can be potently stimulated by exogenous 5-aminolevulinic acid (ALA), resulting in accumulation of the phototoxic intermediate protoporphyrin IX (PPIX). Here we use photodynamic imaging, mass spectrometry, parasite gene disruption, and chemical probes to reveal that vestigial host enzymes in the cytoplasm of Plasmodium-infected erythrocytes contribute to ALA-stimulated heme biosynthesis and that ALA uptake depends on parasite-established permeability pathways. We show that PPIX accumulation in infected erythrocytes can be harnessed for antimalarial chemotherapy using luminol-based chemiluminescence and combinatorial stimulation by low-dose artemisinin to photoactivate PPIX to produce cytotoxic reactive oxygen. This photodynamic strategy has the advantage of exploiting host enzymes refractory to resistance-conferring mutations. DOI: http://dx.doi.org/10.7554/eLife.09143.00

Coniferous Forest Habitat Types of Northern Utah

A habitat type classification is presented for the coniferous forests of northern utah and adjacent areas of idaho and wyoming. The classification and descriptions are based on data from about 1,100 sample stands covering 6 years of reconnaissance sampling

Erratum : GEOTRACES radium isotopes interlaboratory comparison experiment

Author Posting. © Association for the Sciences of Limnology and Oceanography, 2012. This article is posted here by permission of Association for the Sciences of Limnology and Oceanography for personal use, not for redistribution. The definitive version was published in Limnology and Oceanography: Methods 10 (2012): 617, doi:10.4319/lom.2012.10.617.In our original paper, Charette, M. A., H. Dulaiova, M. E. Gonneea, P. B. Henderson, W. S. Moore, J. C. Scholten, and M. K. Pham. 2012. GEOTRACES radium isotopes interlaboratory comparison experiment. Limonol. Oceanogr.: Methods 10:451, the incorrect headers were used for Table 9

GEOTRACES radium isotopes interlaboratory comparison experiment

Author Posting. © Association for the Sciences of Limnology and Oceanography, 2012. This article is posted here by permission of Association for the Sciences of Limnology and Oceanography for personal use, not for redistribution. The definitive version was published in Limnology and Oceanography: Methods 10 (2012): 451-463, doi:10.4319/lom.2012.10.451.In anticipation of the international GEOTRACES program, which will study the global marine biogeochemistry of trace elements and isotopes, we conducted a multi-lab intercomparison for radium isotopes. The intercomparison was in two parts involving the distribution of: (1) samples collected from four marine environments (open ocean, continental slope, shelf, and estuary) and (2) a suite of four reference materials prepared with isotopic standards (circulated to participants as 'unknowns'). Most labs performed well with 228Ra and 224Ra determination, however, there were a number of participants that reported 226Ra, 223Ra, and 228Th (supported 224Ra) well outside the 95% confidence interval. Many outliers were suspected to be a result of poorly calibrated detectors, though other method specific factors likely played a role (e.g., detector leakage, insufficient equilibration). Most methods for radium analysis in seawater involve a MnO2 fiber column preconcentration step; as such, we evaluated the extraction efficiency of this procedure and found that it ranged from an average of 87% to 94% for the four stations. Hence, nonquantitative radium recovery from seawater samples may also have played a role in lab-to-lab variability.This work was funded by grants from the National Science Foundation (OCE- 0751461to M.A.C and H.D. and OCE- 0751867 to W.S.M.)

Obstetric anal sphincter injury: a systematic review of information available on the internet.

OBJECTIVE: There is no systematic evaluation of online health information pertaining to obstetric anal sphincter injury. Therefore, we evaluated the accuracy, credibility, reliability, and readability of online information concerning obstetric anal sphincter injury. MATERIALS AND METHODS: Multiple search engines were searched. The first 30 webpages were identified for each keyword and considered eligible if they provided information regarding obstetric anal sphincter injury. Eligible webpages were assessed by two independent researchers for accuracy (prioritised criteria based upon the RCOG Third and Fourth Degree Tear guideline); credibility; reliability; and readability. RESULTS: Fifty-eight webpages were included. Seventeen webpages (30%) had obtained Health On the Net certification, or Information Standard approval and performed better than those without such approvals (p = 0.039). The best overall performing website was http://www.pat.nhs.uk (score of 146.7). A single webpage (1%) fulfilled the entire criteria for accuracy with a score of 18: www.tamesidehospital.nhs.uk . Twenty-nine webpages (50%) were assessed as credible (scores ≥7). A single webpage achieved a maximum credibility score of 10: www.meht.nhs.uk . Over a third (21 out of 58) were rated as poor or very poor. The highest scoring webpage was http://www.royalsurrey.nhs.uk (score 62). No webpage met the recommended Flesch Reading Ease Score above 70. The intra-class coefficient between researchers was 0.98 (95% CI 0.96-0.99) and 0.94 (95% CI 0.89-0.96) for accuracy and reliability assessments. CONCLUSION: Online information concerning obstetric anal sphincter injury often uses language that is inappropriate for a lay audience and lacks sufficient accuracy, credibility, and reliability

Field guide to the forested plant associations of the Mt. Baker-Snoqualmie National Forest

A classification of forest vegetation is presented for the Mt. Baker-snoqualmie Forest. It is based on the potential National vegetation and uses the plant association as the basic unit. The classification is based on 2464 sample plots distributed across the Forest from 1979 to 1990. Of these 1963 were in late successional stands over 150 years old. An additional 633 plots were taken in non-forest communities or undescribed plant associations. The hierarchical classification includes 4 forest series, 19 plant association groups, and 60 plant associations. Diagnostic keys are presented to aid in the identification of vegetation series and plant associations. Descriptions are presented for each series and association. Plant association descriptions include information about plant species occurrences, distribution, environment and soils, potential timber productivity, management considerations, and comparisons with similar plant associations. Key words: vegetation classification, climax plant communities, potential vegetation, plant association, vegetation series, forest ecology, forest environment, Cascade Mountains