Long-term recovery of vegetation on two experimental crude oil spills in interior Alaska black spruce taiga

1994 ◽  
Vol 72 (8) ◽  
pp. 1171-1177 ◽  
Author(s):  
Charles H. Racine
Keyword(s):  
Crude Oil ◽  
Oil Spills ◽  
Black Spruce ◽  
High Volume ◽  
Belowground Biomass ◽  
Small Areas ◽  
Interior Alaska ◽  
Dead Vegetation ◽  
Low Volume

Vegetation was sampled on two black spruce taiga sites in interior Alaska, 15 and 20 years after crude oil was experimentally applied as low-volume sprays or high-volume point spills. Low volume spray spills that uniformly covered the ground caused initial damage to vegetation, but after 20 years recovery of the understory vegetation was almost complete, with dramatic recovery and expansion of fruticose lichens. High-volume point spills created small areas of surface oil saturation with dead vegetation and little sign of recovery but spread out mostly belowground with little or no apparent effect on the shallowly rooted vegetation above even after 15–20 years. Because winter point spills created a much greater area of surface oil, their effects were more damaging. After 15 years on the saturated surface oiled areas, only Eriophorum vaginatum tussocks survive and grow. At both sites with surface oil, black spruce mortality was high, with no evidence of long-term recovery and with continuing chronic effects after 15 years. However, from a long-term perspective the black spruce taiga ecosystem appears to be able to recover from low volume spray spills and to retain large amounts of crude oil from high-volume point spills belowground with minimal damage to the vegetation. Because of the permafrost, removal of crude oil from this ecosystem by soil excavation is undesirable. In situ acceleration of oil breakdown using fertilizers and bacteria is a possible option; seeding or planting of E. vaginatum on surface-oiled areas may also provide some cover and belowground biomass. Key words: oil spills, taiga, black spruce, interior Alaska, vegetation recovery.

EFFECTS OF EXPERIMENTAL CRUDE OIL SPILLS ON TAIGA AND TUNDRA VEGETATION OF THE CANADIAN ARCTIC

1975 ◽  
Vol 1975 (1) ◽  
pp. 517-525 ◽  
Author(s):  
T.C. Hutchinson ◽  
W. Freedman
Keyword(s):  
Crude Oil ◽  
Oil Spills ◽  
Black Spruce ◽  
Energy Budgets ◽  
Ground Vegetation ◽  
Long Term Effects ◽  
Tundra Vegetation ◽  
Short And Long Term ◽  
Vegetation Species

ABSTRACT Summer and winter crude oil spills have been made on tundra and taiga sites in arctic Canada. The short- and long-term effects of these spills have been recorded, to date, over a 3-year period. Spills were made by even surface spraying and by high intensity point spills. The vegetation present prior to such spills was carefully recorded. All surface spills had a devastating effect on above-ground vegetation. Species did, however, differ markedly in both their ability to survive an oil spill and their ability to recover. Many species, especially lichens, mosses, and liverworts, were killed outright. Some woody and dwarf shrubs were able to produce new, healthy shoots within a few weeks of initial defoliation. The reduced production of storage material, as a result of foliage (and photosynthetic) loss, caused markedly increased plant losses by winter-killing factors. Flowering and reproduction were severely reduced, even in the third summer following a spill. Winter spills had significantly less effect than summer spills. Permafrost was little affected, despite changes in the site energy budgets. Damage appeared greater in exposed taiga sites than on the tundra. Some species, such as black spruce, died throughout a 3-year period, emphasizing the necessity for long-term studies for accurate assessment.

Long-term monitoring of climatic and nutritional affects on tree growth in interior Alaska

2010 ◽  
Vol 40 (7) ◽  
pp. 1325-1335 ◽  
Author(s):  
J. Yarie ◽  
K. Van Cleve
Keyword(s):  
Tree Growth ◽  
Black Spruce ◽  
Growth Period ◽  
Early Spring ◽  
Large Set ◽  
Primary Control ◽  
Forest Types ◽  
Interior Alaska ◽  
State Factor

The comparative analysis of a large set of long-term fertilization and thinning studies in the major forest types of interior Alaska is summarized. Results indicate that nutrient limitations may only occur during the early spring growth period, after which moisture availability is the primary control of tree growth on warm sites. The temperature dynamics of both air and soil set seasonal bounds on the nutrient and moisture dynamics for all forest types. Air and soil temperature limitations are the primary control of intraseasonal growth in the colder topographic locations in interior Alaska. These locations are usually dominated by black spruce (Picea mariana (Mill.) Britton, Sterns, Poggenb.) vegetation types. The seasonal progression of factors controlling growth is strongly tied to the state factor structure of the landscape.

Institutional volume affects long-term survival following lung transplantation in the USA

2019 ◽  
Vol 56 (2) ◽  
pp. 271-276 ◽  
Author(s):  
Arman Kilic ◽  
Thomas G Gleason ◽  
Hiroshi Kagawa ◽  
Ahmet Kilic ◽  
Ibrahim Sultan
Keyword(s):  
Lung Transplantation ◽  
High Volume ◽  
Term Survival ◽  
Long Term Survival ◽  
Kaplan Meier ◽  
The Usa ◽  
Institutional Volume ◽  
Low Volume ◽  
The Impact

Abstract OBJECTIVES The aim of this study was to evaluate the impact of institutional volume on long-term outcomes following lung transplantation (LTx) in the USA. METHODS Adults undergoing LTx were identified in the United Network for Organ Sharing registry. Patients were divided into equal size tertiles according to the institutional volume. All-cause mortality following LTx was evaluated using the risk-adjusted multivariable Cox regression and the Kaplan–Meier analyses, and compared between these volume cohorts at 3 points: 90 days, 1 year (excluding 90-day deaths) and 10 years (excluding 1-year deaths). Lowess smoothing plots and receiver-operating characteristic analyses were performed to identify optimal volume thresholds associated with long-term survival. RESULTS A total of 13 370 adult LTx recipients were identified. The mean annual centre volume was 33.6 ± 20.1. After risk adjustment, low-volume centres were found to be at increased risk for 90-day mortality, [hazard ratio (HR) 1.56, P < 0.001], 1-year mortality excluding 90-day deaths (HR 1.46, P < 0.001) and 10-year mortality excluding 1-year deaths (HR 1.22, P < 0.001). These findings persisted when the centre volume was modelled as a continuous variable. The Kaplan–Meier analysis also demonstrated significant reductions in survival at each of these time points for low-volume centres (each P < 0.001). The 10-year survival conditional on 1-year survival was 37.4% in high-volume centres vs 28.0% in low-volume centres (P < 0.001). The optimal annual volume threshold for long-term survival was 26 LTx/year. CONCLUSIONS The institutional volume impacts long-term survival following LTx, even after excluding deaths within the first post-transplant year. Identifying the processes of care that lead to longer survival in high-volume centres is prudent.

scholarly journals Haptoglobin genotype and outcome after aneurysmal subarachnoid haemorrhage

2020 ◽  
Vol 91 (3) ◽  
pp. 305-313 ◽  
Author(s):  
Matthew J Morton ◽  
Isabel C Hostettler ◽  
Nabila Kazmi ◽  
Varinder S Alg ◽  
Stephen Bonner ◽  
...  
Keyword(s):  
Subarachnoid Haemorrhage ◽  
High Volume ◽  
Expression Level ◽  
Aneurysmal Subarachnoid Haemorrhage ◽  
Term Outcome ◽  
Long Term Outcome ◽  
Fisher Grade ◽  
Haptoglobin Genotype ◽  
Low Volume

ObjectiveAfter aneurysmal subarachnoid haemorrhage (aSAH), extracellular haemoglobin (Hb) in the subarachnoid space is bound by haptoglobin, neutralising Hb toxicity and helping its clearance. Two exons in the HP gene (encoding haptoglobin) exhibit copy number variation (CNV), giving rise to HP1 and HP2 alleles, which influence haptoglobin expression level and possibly haptoglobin function. We hypothesised that the HP CNV associates with long-term outcome beyond the first year after aSAH.MethodsThe HP CNV was typed using quantitative PCR in 1299 aSAH survivors in the Genetics and Observational Subarachnoid Haemorrhage (GOSH) Study, a retrospective multicentre cohort study with a median follow-up of 18 months. To investigate mediation of the HP CNV effect by haptoglobin expression level, as opposed to functional differences, we used rs2000999, a single nucleotide polymorphism associated with haptoglobin expression independent of the HP CNV. Outcome was assessed using modified Rankin and Glasgow Outcome Scores. SAH volume was dichotomised on the Fisher grade. Haemoglobin-haptoglobin complexes were measured in cerebrospinal fluid (CSF) of 44 patients with aSAH and related to the HP CNV.ResultsThe HP2 allele associated with a favourable long-term outcome after high-volume but not low-volume aSAH (multivariable logistic regression). However rs2000999 did not predict outcome. The HP2 allele associated with lower CSF haemoglobin-haptoglobin complex levels. The CSF Hb concentration after high-volume and low-volume aSAH was, respectively, higher and lower than the Hb-binding capacity of CSF haptoglobin.ConclusionThe HP2 allele carries a favourable long-term prognosis after high-volume aSAH. Haptoglobin and the Hb clearance pathway are therapeutic targets after aSAH.

scholarly journals Long-Term Combined Effects of Crude Oil and Dispersant on Sediment Bacterial Community

2020 ◽  
Vol 9 (1) ◽  
pp. 259-263
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
Crude Oil ◽  
Bacterial Community Structure ◽  
Oil Spills ◽  
Bacterial Species ◽  
Combined Effects ◽  
Set Up ◽  
Sediment Bacterial Community

To better understand long-term combined effects of crude oil and dispersant on bacterial community, sediments microcosms were set up in triplicates and treated with dispersant (Corexit 9500A), crude oil, and Corexit 9500A plus crude oil. After 60 days exposure, there was a significant change in the bacterial community structure in all treatments. The shift in the bacterial community structure in Corexit 9500A plus crude oil treatment was considerably different from those by either Corexit 9500A or crude oil. DNA sequence analysis showed that Hydrocarboniphaga effuse, Parvibaculum lavamentivorans,and Alicyclobacillus ferrooxydans were the major bacterial species in crude oil treatment. Pandoraea thiooxydans, Janthinobacterium sp. and Hyphomicrobium nitrativorans were the most dominant species in Corexit 9500A treatment. The species Janthinobacterium sp., Parvibaculum lavamentivorans, and Dyella sp. were enriched in Corexit 9500A plus crude oil treatment. The majority of the detected species were hydrocarbons degraders. The study showed that Corexit 9500A addition enhanced the biodegradation rate by increasing the diversity and richness of hydrocarbons degrading species. Corexit A9500 application should be considered during crude oil spills to evaluate environmental impacts.

Patients with undetectable PSA 2 years after docetaxel for metastatic castration sensitive prostate cancer (mCSPC).

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. e17044-e17044
Author(s):  
Mohammad O. Atiq ◽  
Shruti Gandhy ◽  
Fatima Karzai ◽  
Marijo Bilusic ◽  
Lisa M. Cordes ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Treatment Options ◽  
High Volume ◽  
Clinical Activity ◽  
Castration Resistant Prostate Cancer ◽  
Therapeutic Cancer Vaccine ◽  
Volume Group ◽  
Low Volume ◽  
To Receive

e17044 Background: Patients with mCPSC have multiple treatment options to combine with androgen deprivation therapy (ADT) including docetaxel, abiraterone, enzalutamide and apalutamide, all of which have demonstrated a survival advantage. While oral anti-androgens are administered daily until progression but are less toxic, docetaxel has more upfront side effects. One of the advantages of using docetaxel is that the 6-cycle regimen (over approximately 4 months) potentially affords patients a respite from daily therapies thereafter. Furthermore, docetaxel may be more cost-effective. In this prospective study, mCSPC patients were treated with docetaxel and Prostvac, a therapeutic cancer vaccine. Since this study was initiated, Prostvac did not demonstrate independent clinical activity in a phase 3 trial in metastatic castration resistant prostate cancer. Nonetheless, this study provides an opportunity to evaluate responses to docetaxel-based therapy in mCSPC. Methods: Eligible patients included those with mCSPC and ECOG of ≤ 2. All patients were treated with docetaxel and were planned to receive 75mg/m2 for 6 cycles within 4 months of starting ADT, as per the CHAARTED regimen. Patients were randomized to receive Prostvac prior to, concurrent with or after docetaxel. Patients were restaged annually with CT and Tc99 bone scan. The study was powered to evaluate immunologic responses, which is ongoing. For the purposes of this analysis, all patients were analyzed as one group and long-term PSA responses were evaluated. Results: The study enrolled 73 patients. Age range was 41-86 with a median of 63 years. Race distribution was 71.6% White, 20.3% Black, 4.1% other, and 4.1% unknown. Gleason scores were 6 (4.1%), 7 (21.6%), and 8-10 (68.9%), with 5.4% being unknown. Median pre-ADT PSA was 34.75 ng/mL. Low-volume disease represented 41.1% of patients and high-volume was 58.9%. After 2 years from the start of ADT, 22% of all patients had PSA values of ≤ 0.2 ng/mL. This included 37% of the low-volume group and 12% of the high-volume group. Three years from the start of ADT, 14% of all patients had PSA values ≤ 0.2 ng/mL (20% of the low-volume group, 9% of the high-volume group). Conclusions: These data highlight long-term outcomes of 6 cycles of docetaxel for men with mCSPC. Although there are concerns about the short-term toxicity of docetaxel, there is potential for prolonged stable disease after ̃4 months of chemotherapy that allows these patients to defer additional oral anti-androgen therapy for years in some patients. The proportions of patients presented here are an underestimate of those who could continue to be monitored for slowly rising, but low PSAs, before starting the next line of therapy. Additional research is required to determine the optimal therapeutic sequence for men diagnosed with mCSPC and long-term implications for quality of life and cost-effectiveness. Clinical trial information: NCT02649855.

scholarly journals Influence of Individual Surgeon Volume on Oncological Outcome of Colorectal Cancer Surgery

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Marleen Buurma ◽  
Hidde M. Kroon ◽  
Marlies S. Reimers ◽  
Peter A. Neijenhuis
Keyword(s):  
Colorectal Cancer ◽  
Multivariate Analysis ◽  
Disease Free Survival ◽  
High Volume ◽  
Free Survival ◽  
Significant Difference ◽  
Low Volume ◽  
The Impact ◽  
Disease Free

Background. Surgery performed by a high-volume surgeon improves short-term outcomes. However, not much is known about long-term effects. Therefore we performed the current study to evaluate the impact of high-volume colorectal surgeons on survival.Methods. We conducted a retrospective analysis of our prospectively collected colorectal cancer database between 2004 and 2011. Patients were divided into two groups: operated on by a high-volume surgeon (>25 cases/year) or by a low-volume surgeon (<25 cases/year). Perioperative data were collected as well as follow-up, recurrence rates, and survival data.Results. 774 patients underwent resection for colorectal malignancies. Thirteen low-volume surgeons operated on 453 patients and 4 high-volume surgeons operated on 321 patients. Groups showed an equal distribution for preoperative characteristics, except a higher ASA-classification in the low-volume group. A high-volume surgeon proved to be an independent prognostic factor for disease-free survival in the multivariate analysisP=0.04. Although overall survival did show a significant difference in the univariate analysisP<0.001it failed to reach statistical significance in the multivariate analysisP=0.09.Conclusions. In our study, a higher number of colorectal cases performed per surgeon were associated with longer disease-free survival. Implementing high-volume surgery results in improved long-term outcome following colorectal cancer.

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