The effect of refuge trees on a paper birch ectomycorrhiza community

2000 ◽  
Vol 77 (10) ◽  
pp. 1523-1528 ◽  
Author(s):  
J M Kranabetter

Live trees within forest disturbances could support refugia populations of ectomycorrhizae fungi from which to reestablish ectomycorrhiza communities during forest succession. The effectiveness of refuge paper birch trees (Betula papyrifera Marsh.) in maintaining a forest ectomycorrhiza community on birch seedlings, both in clearcuts and forests, in northwest British Columbia was examined. Seedlings next to refuge birch trees in clearcuts had equal levels of average morphotype richness and eveness as seedlings next to mature birch trees in forests. Seedlings outside of the rooting zone of refuge trees had significantly less average morphotype richness in both clearcuts and forests, decreasing by 38 and 15%, respectively. The ectomycorrhiza communities were also more unique (lower community similarity) next to refuge trees than for seedlings away from refuge trees, especially in clearcuts. These treatment effects could be explained by differences in the ability to disperse and establish between early-stage, multi-stage, and late-stage ectomycorrhiza fungi. The results suggest refuge trees would be effective in forest management as sources of inocula for multi-stage and late-stage fungi.

2008 ◽  
Vol 38 (7) ◽  
pp. 1996-2002 ◽  
Author(s):  
Guillaume Giroud ◽  
Alain Cloutier ◽  
Jérôme Alteyrac

Normal paper birch ( Betula papyrifera Marsh.) wood has a clear and uniform color. However, some paper birch trees contain reddish-brown-, discolored wood known as red heartwood. Its occurrence, proportion, and vertical distribution were investigated. One hundred and fifty trees were randomly sampled from three stands located at the Montmorency Forest, 75 km north of Quebec City, Quebec, Canada. A subsample of 18 trees showing occurrence of red heartwood at stump height were felled, and 5 cm thick disks were cut at every 0.5 m of height. Red heartwood volume, proportion, and vertical distribution were determined from the disks. Trees with larger diameter at breast height and lower tree height had a higher probability of red heartwood occurrence. Red heartwood starts occurring in 40-year-old trees on average in the stands studied. The volume of red heartwood was positively correlated with tree age, and the proportion of red heartwood was positively related to tree age, and negatively related to the amount of sunlight on the live crown. Red heartwood proportion was 13.3% of the tree merchantable volume, mostly located under the live crown.


2011 ◽  
Vol 41 (7) ◽  
pp. 1491-1499 ◽  
Author(s):  
Benoît Belleville ◽  
Alain Cloutier ◽  
Alexis Achim

Red heartwood, a dark nonhomogenous discolouration in paper birch trees ( Betula papyrifera Marsh.), limits the applications and uses of sawn boards to nonvisible low-value products, thus resulting in substantial value loss. The occurrence and distribution of red heartwood were investigated in 12 paper birch trees grown in the province of Quebec, Canada. The youngest tree was 62 years old at breast height and the oldest 86 years old for an average of 75 years old. In this study, 225 occurrences of external traits, relating to branch scars and forks, previously proposed as initiation points for red heartwood were identified and measured. The distribution of red heartwood was digitally mapped and the effect of these external traits on the red heartwood surface and shape inside each tree was examined. Results show that red heartwood initiates from an external trait and that multiple external traits can contribute to the development of a red heartwood column following the longitudinal axis of the stem. Red heartwood appeared to initiate mainly from external traits at the base of the tree. A modelling exercise indicated that the width of the red heartwood column inside a standing tree can be estimated from branch scar width and height from the ground. Tree vigour could not be linked to the proportion of red heartwood inside standing trees. A three-dimensional analysis of log shape could potentially be used to detect red heartwood presence in a log before processing to optimize the log sawing pattern.


1979 ◽  
Vol 111 (3) ◽  
pp. 317-322 ◽  
Author(s):  
Richard A. Werner

AbstractSpear-marked black moth, Rheumaptera hastata (L.), females tended to oviposit more readily on paper birch, Betula papyrifera Marsh., than other deciduous plants indigenous to interior Alaska. Larval feeding intensity was about 40% higher on birch foliage than on other host plants. Larvae reared on various host plant species differed in survival, development rate, and body weight. Food quality of host plants on which females were reared as larvae affected oviposition, fecundity, and egg viability. Larval development rate and survival decreased when fed foliage from birch trees that were repeatedly defoliated for 2 and 3 years.


2021 ◽  
pp. 073112142110286
Author(s):  
Alexander B. Kinney ◽  
Nicholas J. Rowland

This is an article that draws on the institutional work literature about provisional institutions. To date, nearly every U.S. sector has been impacted by COVID-19. To sustain their core missions, highly institutionalized organizations such as universities have had to rethink foundational structures and policies. Using a historical ethnographic approach to investigate records from faculty senate deliberations at “Rural State University” (RSU), the authors examine the implementation of a temporary grading policy to supplement traditional, qualitative grades spring 2020 during the outbreak. The authors find that RSU implemented a temporary, supplemental grading policy as a provisional institution to momentarily supersede traditional grading as a means to—as soon as possible—return to it. This finding contrasts with the common understanding that provisional institutions operate primarily as a temporary solution to a social problem that leads to more stable and enduring, ostensibly nonprovisional institutions. The temporary grading policy, the authors argue, constitutes a “late-stage” provisional institution and, with this new lens, subsequently characterize the more commonplace understanding of provisional institutions as “early-stage.” This contribution has theoretical implications for studies of institutions and empirical implications for research on shared governance and disruption in higher education.


2021 ◽  
pp. 003335492199917
Author(s):  
Lindsey A. Jones ◽  
Katherine C. Brewer ◽  
Leslie R. Carnahan ◽  
Jennifer A. Parsons ◽  
Blase N. Polite ◽  
...  

Objective For colon cancer patients, one goal of health insurance is to improve access to screening that leads to early detection, early-stage diagnosis, and polyp removal, all of which results in easier treatment and better outcomes. We examined associations among health insurance status, mode of detection (screen detection vs symptomatic presentation), and stage at diagnosis (early vs late) in a diverse sample of patients recently diagnosed with colon cancer from the Chicago metropolitan area. Methods Data came from the Colon Cancer Patterns of Care in Chicago study of racial and socioeconomic disparities in colon cancer screening, diagnosis, and care. We collected data from the medical records of non-Hispanic Black and non-Hispanic White patients aged ≥50 and diagnosed with colon cancer from October 2010 through January 2014 (N = 348). We used logistic regression with marginal standardization to model associations between health insurance status and study outcomes. Results After adjusting for age, race, sex, and socioeconomic status, being continuously insured 5 years before diagnosis and through diagnosis was associated with a 20 (95% CI, 8-33) percentage-point increase in prevalence of screen detection. Screen detection in turn was associated with a 15 (95% CI, 3-27) percentage-point increase in early-stage diagnosis; however, nearly half (47%; n = 54) of the 114 screen-detected patients were still diagnosed at late stage (stage 3 or 4). Health insurance status was not associated with earlier stage at diagnosis. Conclusions For health insurance to effectively shift stage at diagnosis, stronger associations are needed between health insurance and screening-related detection; between screening-related detection and early stage at diagnosis; or both. Findings also highlight the need to better understand factors contributing to late-stage colon cancer diagnosis despite screen detection.


Author(s):  
L. Schmidt ◽  
O. Sehic ◽  
C. Wild

Abstract Background We considered the extent of the contribution of publicly funded research to the late-stage clinical development of pharmaceuticals and medicinal products, based on the European Commission (EC) FP7 research funding programme. Using two EC FP7-HEALTH case study examples—representing two types of outcomes—we then estimated wider public and charitable research funding contributions. Methods Using the publicly available database of FP7-HEALTH funded projects, we identified awards relating to late-stage clinical development according to the systematic application of inclusion and exclusion criteria, classified them according to product type and clinical indication, and calculated total EC funding amounts. We then identified two case studies representing extreme outcomes: failure to proceed with the product (hepatitis C vaccine) and successful market authorisation (Orfadin® for alkaptonuria). Total public and philanthropic research funding contributions to these products were then estimated using publicly available information on funding. Results 12.3% (120/977) of all EC FP7-HEALTH awards related to the funding of late-stage clinical research, totalling € 686,871,399. Pharmaceutical products and vaccines together accounted for 84% of these late-stage clinical development research awards and 70% of its funding. The hepatitis C vaccine received total European Community (FP7 and its predecessor, EC Framework VI) funding of €13,183,813; total public and charitable research funding for this product development was estimated at € 77,060,102. The industry sponsor does not consider further development of this product viable; this now represents public risk investment. FP7 funding for the late-stage development of Orfadin® for alkaptonuria was so important that the trials it funded formed the basis for market authorisation, but it is not clear whether the price of the treatment (over €20,000 per patient per year) adequately reflects the substantial public funding contribution. Conclusions Public and charitable research funding plays an essential role, not just in early stage basic research, but also in the late-stage clinical development of products prior to market authorisation. In addition, it provides risk capital for failed products. Within this context, we consider further discussions about a public return on investment and its reflection in pricing policies and decisions justified.


Cancers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 3975
Author(s):  
Marco A. De Velasco ◽  
Yurie Kura ◽  
Naomi Ando ◽  
Noriko Sako ◽  
Eri Banno ◽  
...  

Significant improvements with apalutamide, a nonsteroidal antiandrogen used to treat patients suffering from advanced prostate cancer (PCa), have prompted evaluation for additional indications and therapeutic development with other agents; however, persistent androgen receptor (AR) signaling remains problematic. We used autochthonous mouse models of Pten-deficient PCa to examine the context-specific antitumor activity of apalutamide and profile its molecular responses. Overall, apalutamide showed potent antitumor activity in both early-stage and late-stage models of castration-naïve prostate cancer (CNPC). Molecular profiling by Western blot and immunohistochemistry associated persistent surviving cancer cells with upregulated AKT signaling. While apalutamide was ineffective in an early-stage model of castration-resistant prostate cancer (CRPC), it tended to prolong survival in late-stage CRPC. Molecular features associated with surviving cancer cells in CRPC included upregulated aberrant-AR, and phosphorylated S6 and proline-rich Akt substrate of 40 kDa (PRAS40). Strong synergy was observed with the pan-AKT inhibitor GSK690693 and apalutamide in vitro against the CNPC- and CRPC-derived cell lines and tended to improve the antitumor responses in CNPC but not CRPC in vivo. Upregulation of signal transducer and activator of transcription 3 (STAT3) and proviral insertion in murine-1 (PIM-1) were associated with combined apalutamide/GSK690693. Our findings show that apalutamide can attenuate Pten-deficient PCa in a context-specific manner and provides data that can be used to further study and, possibly, develop additional combinations with apalutamide.


2021 ◽  
Vol 28 (3) ◽  
pp. 1946-1956
Author(s):  
Aisha K. Lofters ◽  
Evgenia Gatov ◽  
Hong Lu ◽  
Nancy N. Baxter ◽  
Sara J. T. Guilcher ◽  
...  

Lung cancer is the most common cancer and cause of cancer death in Canada, with approximately 50% of cases diagnosed at stage IV. Sociodemographic inequalities in lung cancer diagnosis have been documented, but it is not known if inequalities exist with respect to immigration status. We used multiple linked health-administrative databases to create a cohort of Ontarians 40–105 years of age who were diagnosed with an incident lung cancer between 1 April 2012 and 31 March 2017. We used modified Poisson regression with robust standard errors to examine the risk of diagnosis at late vs. early stage among immigrants compared to long-term residents. The fully adjusted model included age, sex, neighborhood-area income quintile, number of Aggregated Diagnosis Group (ADG) comorbidities, cancer type, number of prior primary care visits, and continuity of care. Approximately 62% of 38,788 people with an incident lung cancer from 2012 to 2017 were diagnosed at a late stage. Immigrants to the province were no more likely to have a late-stage diagnosis than long-term residents (63.5% vs. 62.0%, relative risk (RR): 1.01 (95% confidence interval (CI): 0.99–1.04), adjusted relative risk (ARR): 1.02 (95% CI: 0.99–1.05)). However, in fully adjusted models, people with more comorbidities were less likely to have a late-stage diagnosis (adjusted relative risk (ARR): 0.82 (95% CI: 0.80–0.84) for those with 10+ vs. 0–5 ADGs). Compared to adenocarcinoma, small cell carcinoma was more likely to be diagnosed at a late stage (ARR: 1.29; 95% CI: 1.27–1.31), and squamous cell (ARR: 0.89; 95% CI: 0.87–0.91) and other lung cancers (ARR: 0.93; 95% CI: 0.91–0.94) were more likely to be diagnosed at an early stage. Men were also slightly more likely to have late-stage diagnosis in the fully adjusted model (ARR: 1.08; 95% CI: 1.05–1.08). Lung cancer in Ontario is a high-fatality cancer that is frequently diagnosed at a late stage. Having fewer comorbidities and being diagnosed with small cell carcinoma was associated with a late-stage diagnosis. The former group may have less health system contact, and the latter group has the lung cancer type most closely associated with smoking. As lung cancer screening programs start to be implemented across Canada, targeted outreach to men and to smokers, increasing awareness about screening, and connecting every Canadian with primary care should be system priorities.


1997 ◽  
Vol 481 ◽  
Author(s):  
Celeste Sagui ◽  
Dean Stinson O'Gorman ◽  
Martin Grant

ABSTRACTIn this work we have re-examined the classical problem of nucleation and growth. A new model considers the correlations among droplets and naturally incorporates the crossover from the early-stage, nucleation dominated regime to the scaling, late-stage, coarsening regime within a single framework.


Sign in / Sign up

Export Citation Format

Share Document