Carbon accretion in unthinned and thinned young-growth forest stands of the Alaskan perhumid coastal temperate rainforest.

BACKGROUND: Accounting for carbon gains and losses in young-growth forests is a key part of carbon assessments. A common silvicultural practice in young forests is thinning to increase the growth rate of residual trees. However, the effect of thinning on total stand carbon stock in these stands is uncertain. In this study we used data from 284 long-term growth and yield plots to quantify the carbon stock in unthinned and thinned young growth conifer stands in the Alaskan coastal temperate rainforest. We estimated carbon stocks and carbon accretion rates for three thinning treatments (basal area removal of 47, 60, and 73 %) and a no-thin treatment across a range of productivity classes and ages. We also accounted for the carbon content in dead trees to quantify the influence of both thinning and natural mortality in unthinned stands. RESULTS: The total tree carbon stock in naturally-regenerating unthinned young-growth forests estimated as the asymptote of the accretion curve was 484 (±26) Mg C ha-1 for live and dead trees and 398 (±20) Mg C ha-1 for live trees only. The total tree carbon stock was reduced by 16, 26, and 39 % at stand age 40 y across the increasing range of basal area removal. Modeled linear carbon accretion rates of stands 40 years after treatment were not markedly different with increasing intensity of basal area removal from reference stand values of 4.45 Mg C ha-1 year-1to treatment stand values of 5.01, 4.83, and 4.68 Mg C ha-1 year-1 respectively. However, the carbon stock reduction in thinned stands compared to the stock of carbon in the unthinned plots was maintained over the entire 100 year period of observation. CONCLUSIONS: Thinning treatments in regenerating forest stands reduce forest carbon stocks, while carbon accretion rates recovered and were similar to unthinned stands. However, that the reduction of carbon stocks in thinned stands persisted for a century indicate that the unthinned treatment option is the optimal choice for short-term carbon sequestration. Other ecologically beneficial results of thinning may override the loss of carbon due to treatment. Our model estimates can be used to calculate regional carbon losses, alleviating uncertainty in calculating the carbon cost of the treatments

Incompatibility reactions and nuclear condition of three Phellinus species

Phellinus arctostaphyli (Long) Niemela, P. igniarius (L. ex Fr.) Quel., and P. tremulae (Bond.) Bond. et Boriss., heartrotting hymenomycetes in the family Hymenochaetaceae (Aphyllophorales), all conform to a multi-allelic heterothallic mating system. Both compatible and incompatible reactions result from pairings of homokaryons from the same basidiocarp. Homokaryons isolated from different basidiocarps, but the same species, are fully compatible. Cultural characteristics are not useful in distinguishing between homokaryons and heterokaryons. However, heterokaryons exhibit significantly faster growth rate in culture than homokaryons. Antagonistic responses between paired homokaryotic isolates serve as an indicator of sexual incompatibility; sexually compatible pairs acquire the faster growth rate of heterokaryons. Antagonistic characteristics similar in appearance to sexual incompatibility occur between paired heterokaryotic isolates displaying vegetative incompatibility. These three species are similar in the variation of the nuclear condition throughout their life cycles. Basidiospores are produced with one nucleus, but are ordinarily binucleate prior to germination. Both homokaryons and heterokaryons have a variable number of unpaired nuclei between septa. The dikaryophase is delayed until basidiocarp formation, when the dikaryon can be found in young basidia and mycelium underlying basidia. Incompatible reactions in hybridization attempts support the segregation of these three closely related species

New directions in building a scientific social network: Experiences in the Supercourse project and application to Central Asia.

Introduction: Networking leaders in the field of public health and medicine is very important for improving health locally and globally, especially in times of disaster. Methods: Fishing can best be defined as using an internet search engine to find the name and email address of the person or organization that is being sought. Results: With over 500 hours of work, the group compiled a list of nearly 2,000 email addresses of Ministers of Health, deans of the 1,800 medical schools and schools of public health, and heads of medical and public health societies

New directions in building a scientific social network: Experiences in the Supercourse project and application to Central Asia

oai:ojs.cajgh.pitt.edu:article/3IntroductionNetworking leaders in the field of public health and medicine is very important for improving health locally and globally, especially in times of disaster.MethodsFishing can best be defined as using an internet search engine to find the name and email address of the person or organization that is being sought.ResultsWith over 500 hours of work, the group compiled a list of nearly 2,000 email addresses of Ministers of Health, deans of the 1,800 medical schools and schools of public health, and heads of medical and public health societies.ConclusionsFishing for deans and others is an important task, albeit just the first step in building a scientific social network.  Upon creation of a database of names, other steps must be taken, such as meeting with others, exchanging information, and forming new collaborations before a scientific social network is successfully completed

SeaFlow Data V1, High-Resolution Abundance, Size and Biomass of Small Phytoplankton in the North Pacific

SeaFlow is an underway flow cytometer that provides continuous shipboard observations of the abundance and optical properties of small phytoplankton (\u3c5 μm in equivalent spherical diameter, ESD). Here we present data sets consisting of SeaFlow-based cell abundance, forward light scatter, and pigment fluorescence of individual cells, as well as derived estimates of ESD and cellular carbon content of picophytoplankton, which includes the cyanobacteria Prochlorococcus, Synechococcus and small-sized Crocosphaera (\u3c5 μm ESD), and picophytoplankton and nanophytoplankton (2–5 μm ESD). Data were collected in surface waters (≈5 m depth) from 27 oceanographic cruises carried out in the Northeast Pacific Ocean between 2010 and 2018. Thirteen cruises provide high spatial resolution (≈1 km) measurements across 32,500 km of the Northeast Pacific Ocean and 14 near-monthly cruises beginning in 2015 provide seasonal distributions at the long-term sampling site (Station ALOHA) of the Hawaii Ocean Time-Series. These data sets expand our knowledge of the current spatial and temporal distributions of picophytoplankton in the surface ocean

Genetic dissection of the type VI secretion system in Acinetobacter and identification of a novel peptidoglycan hydrolase, TagX, required for its biogenesis

The type VI secretion system (T6SS) is a widespread secretory apparatus produced by Gram-negative bacteria that has emerged as a potent mediator of antibacterial activity during interbacterial interactions. Most Acinetobacter species produce a genetically conserved T6SS, although the expression and functionality of this system vary among different strains. Some pathogenic Acinetobacter baumannii strains activate this secretion system via the spontaneous loss of a plasmid carrying T6SS repressors. In this work, we compared the expression of T6SS-related genes via transcriptome sequencing and differential proteomics in cells with and without the plasmid. This approach, together with the mutational analysis of the T6SS clusters, led to the determination of the genetic components required to elaborate a functional T6SS in the nosocomial pathogen A. baumannii and the nonpathogen A. baylyi. By constructing a comprehensive combination of mutants with changes in the T6SS-associated vgrG genes, we delineated their relative contributions to T6SS function. We further determined the importance of two effectors, including an effector-immunity pair, for antibacterial activity. Our genetic analysis led to the identification of an essential membrane-associated structural component named TagX, which we have characterized as a peptidoglycan hydrolase possessing l,d-endopeptidase activity. TagX shows homology to known bacteriophage l,d-endopeptidases and is conserved in the T6SS clusters of several bacterial species. We propose that TagX is the first identified enzyme that fulfills the important role of enabling the transit of T6SS machinery across the peptidoglycan layer of the T6SS-producing bacterium

Host–parasite distributions under changing climate: Tsuga heterophylla and Arceuthobium tsugense in Alaska

Dwarf mistletoes (Arceuthobium species) influence many processes within forested ecosystems, but few studies have examined their distribution in relation to climate. An analysis of 1549 forested plots within a 14.5 million ha region of southeast Alaska provided strong indications that climate currently limits hemlock dwarf mistletoe (Arceuthobium tsugense (Rosendahl) G.N. Jones) to a subset of the range of its primary tree host, western hemlock (Tsuga heterophylla (Raf.) Sarg.), with infection varying from a high of 20% of trees at sea level to only 5% by 200 m elevation. Three types of modeling approaches (logistic, most similar neighbors, and random forests) were tested for the ability to simultaneously predict abundance and distribution of host and pathogen as a function of climate variables. Current distribution was explained well by logistic models using growing degree-days, indirect and direct solar radiation, rainfall, snowfall, slope, and minimum temperatures, although accuracy for predicting A. tsugense presence at a particular location was only 38%. For future climate scenarios (A1B, A2, and B1), projected increases for A. tsugense habitat over a century ranged from a low of 374% to a high of 757%, with differences between modeling approaches contributing more to uncertainty than differences between climate scenarios

Lung cancer lymph node micrometastasis detection using real-time polymerase chain reaction: Correlation with vascular endothelial growth factor expression

ObjectivesLymph node staging provides critical information in patients with non–small cell lung cancer (NSCLC). Lymphangiogenesis may be an important contributor to the pathophysiology of lymphatic metastases. We hypothesized that the presence of lymph node micrometastases positively correlates with vascular endothelial growth factors (VEGFs) A, C, and D as well as VEGF-receptor-3 (lymphangiogenic factors) expression in lymph nodes.MethodsForty patients with NSCLC underwent preoperative positron emission tomography-computed tomography and mediastinoscopy. Real-time polymerase chain reaction (RT-PCR) assays for messenger RNA expression of epithelial markers (ie, cytokeratin 7; carcinoembryonic antigen-related cell adhesion molecule 5; and palate, lung, and nasal epithelium carcinoma-associated protein) were performed in selected fluorodeoxyglucose-avid lymph nodes. VEGF-A, VEGF-C, VEGF-D, and VEGF receptor-3 expression levels were measured in primary tumors and lymph nodes. Wilcoxon rank sum test was run for the association between the RT-PCR epithelial marker levels and VEGF expression levels in the lymph nodes.ResultsRT-PCR for cytokeratin 7; carcinoembryonic antigen-related cell adhesion molecule 5; or palate, lung, and nasal epithelium carcinoma-associated protein indicated lymph node micrometastatic disease in 19 of 35 patients (54%). There was a high correlation between detection of micrometastases and VEGF-A, VEGF-C, VEGF-D, or VEGF receptor-3 expression levels in lymph nodes. Median follow-up was 12.6 months.ConclusionsRT-PCR analysis of fluorodeoxyglucose-avid lymph nodes results in up-staging a patient's cancer. Micrometastases correlate with the expression of VEGF in lymph nodes in patients with NSCLC. This may reflect the role of lymphangiogenesis in promoting metastases

SeaFlow data v1, high-resolution abundance, size and biomass of small phytoplankton in the North Pacific

SeaFlow is an underway flow cytometer that provides continuous shipboard observations of the abundance and optical properties of small phytoplankton (<5 mu m in equivalent spherical diameter, ESD). Here we present data sets consisting of SeaFlow-based cell abundance, forward light scatter, and pigment fluorescence of individual cells, as well as derived estimates of ESD and cellular carbon content of picophytoplankton, which includes the cyanobacteria Prochlorococcus, Synechococcus and small-sized Crocosphaera (<5 mu m ESD), and picophytoplankton and nanophytoplankton (2-5 mu m ESD). Data were collected in surface waters (approximate to 5 m depth) from 27 oceanographic cruises carried out in the Northeast Pacific Ocean between 2010 and 2018. Thirteen cruises provide high spatial resolution (approximate to 1 km) measurements across 32,500 km of the Northeast Pacific Ocean and 14 near-monthly cruises beginning in 2015 provide seasonal distributions at the long-term sampling site (Station ALOHA) of the Hawaii Ocean Time-Series. These data sets expand our knowledge of the current spatial and temporal distributions of picophytoplankton in the surface ocean

Forest carbon sequestration:the impact of forest management

In this chapter, we describe alternative ways in which forests and forestry can help to mítigate climate change, along with the potential impact of these activities. The three carbon storage compartments should be considered inall impact estimates. Carbon content in living biomass is easily estimated via species-specific equations or by applying factors to oven-dry biomass weights (e.g.,lbañez et al.,2002, Herrero et al.,2011,Castaño and Bravo, 2012).Litter carbon content has been analysed in many studies on primary forest productivity, though information regarding the influence of forest management on litter carbon content is less abundant (Blanco et al., 2006). In the last decade,efforts have been made to assess soil carbon in forests, but studies on the effect of forest management on soils show discrepancies (Lindner and Karjalainen,2007).Hoover (2011), for example,found no difference in forest floor carbon stocks among stands subjected to partial or complete harvest treatments in the United States.Instituto Universitario de Gestión Forestal Sostenibl