Publications by authors named "R C Scott"

5,653 Publications

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The three major axes of terrestrial ecosystem function.

Nature 2021 Sep 22. Epub 2021 Sep 22.

Max Planck Institute for Biogeochemistry, Jena, Germany.

The leaf economics spectrum and the global spectrum of plant forms and functions revealed fundamental axes of variation in plant traits, which represent different ecological strategies that are shaped by the evolutionary development of plant species. Ecosystem functions depend on environmental conditions and the traits of species that comprise the ecological communities. However, the axes of variation of ecosystem functions are largely unknown, which limits our understanding of how ecosystems respond as a whole to anthropogenic drivers, climate and environmental variability. Here we derive a set of ecosystem functions from a dataset of surface gas exchange measurements across major terrestrial biomes. We find that most of the variability within ecosystem functions (71.8%) is captured by three key axes. The first axis reflects maximum ecosystem productivity and is mostly explained by vegetation structure. The second axis reflects ecosystem water-use strategies and is jointly explained by variation in vegetation height and climate. The third axis, which represents ecosystem carbon-use efficiency, features a gradient related to aridity, and is explained primarily by variation in vegetation structure. We show that two state-of-the-art land surface models reproduce the first and most important axis of ecosystem functions. However, the models tend to simulate more strongly correlated functions than those observed, which limits their ability to accurately predict the full range of responses to environmental changes in carbon, water and energy cycling in terrestrial ecosystems.
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http://dx.doi.org/10.1038/s41586-021-03939-9DOI Listing
September 2021

Relationship of low molecular weight fluorophore levels with clinical factors and fenofibrate effects in adults with type 2 diabetes.

Sci Rep 2021 Sep 21;11(1):18708. Epub 2021 Sep 21.

National Health and Medical Research Council Clinical Trials Centre, The University of Sydney, Level 6 Medical Foundation Building, 92-94 Parramatta Rd, Camperdown, Sydney, NSW, 2050, Australia.

People with diabetes are at risk of chronic complications and novel biomarkers, such as Advanced glycation end-products (AGEs) may help stratify this risk. We assessed whether plasma low-molecular weight AGEs, also known as LMW-fluorophores (LMW-F), are associated with risk factors, predict complications, and are altered by fenofibrate in adults with type 2 diabetes. Plasma LMW-F were quantified at baseline, after six weeks fenofibrate, and one year post-randomisation to fenofibrate or placebo. LMW-F associations with existing and new composite vascular complications were determined, and effects of fenofibrate assessed. LMW-F correlated positively with age, glycated haemoglobin (HbA1c), pulse pressure, kidney dysfunction and inflammation; and negatively with urate, body mass index, oxidative stress and leptin, albeit weakly (r = 0.04-0.16, all p < 0.01). Independent determinants of LMW-F included smoking, diastolic blood pressure, prior cardiovascular disease or microvascular complications, Caucasian ethnicity, kidney function, HbA1c and diabetes duration (all p ≤ 0.01). Baseline LMW-F tertiles correlated with on-trial macrovascular and microvascular complications (trend p < 0.001) on univariate analyses only. Six weeks of fenofibrate increased LMW-F levels by 21% (p < 0.001). In conclusion, LMW-F levels correlate with many risk factors and chronic diabetes complications, and are increased with fenofibrate. LMW-F tertiles predict complications, but not independently of traditional risk factors.
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http://dx.doi.org/10.1038/s41598-021-98064-yDOI Listing
September 2021

Emergence of an early SARS-CoV-2 epidemic in the United States.

Cell 2021 09 27;184(19):4939-4952.e15. Epub 2021 Jul 27.

Department of Microbiology and Immunology, School of Medicine, Tulane University, New Orleans, LA 70112, USA; Department of Physiology, Tulane University School of Medicine, New Orleans, LA 70112, USA.

The emergence of the COVID-19 epidemic in the United States (U.S.) went largely undetected due to inadequate testing. New Orleans experienced one of the earliest and fastest accelerating outbreaks, coinciding with Mardi Gras. To gain insight into the emergence of SARS-CoV-2 in the U.S. and how large-scale events accelerate transmission, we sequenced SARS-CoV-2 genomes during the first wave of the COVID-19 epidemic in Louisiana. We show that SARS-CoV-2 in Louisiana had limited diversity compared to other U.S. states and that one introduction of SARS-CoV-2 led to almost all of the early transmission in Louisiana. By analyzing mobility and genomic data, we show that SARS-CoV-2 was already present in New Orleans before Mardi Gras, and the festival dramatically accelerated transmission. Our study provides an understanding of how superspreading during large-scale events played a key role during the early outbreak in the U.S. and can greatly accelerate epidemics.
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http://dx.doi.org/10.1016/j.cell.2021.07.030DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8313480PMC
September 2021

Providers PrEP: Identifying Primary Health care Providers' Biases as Barriers to Provision of Equitable PrEP Services.

J Acquir Immune Defic Syndr 2021 Oct;88(2):165-172

Center for AIDS Prevention Studies, Prevention Research Center, Division of Prevention Science, University of California, California, San Francisco.

Background: Despite their disparately high HIV incidence and voiced willingness to use pre-exposure prophylaxis (PrEP), Black cisgender women's knowledge and uptake of PrEP are low, especially relative to White cisgender women and men who have sex with men. Mounting evidence demonstrates that health care provider recommendations are a critical factor in women's awareness, willingness, and ability to uptake PrEP. Health care providers may make clinical judgments about who is (not) a good candidate for PrEP based on unconscious and conscious stereotypes and prejudice.

Setting: We conducted an online experiment among N = 160 health care providers with prescribing privileges in the 48 HIV hotspot counties.

Method: Providers received 1 of 4 vignettes about a PrEP eligible woman. Vignettes varied by patient race and substance use status. Then, providers reported their willingness to discuss PrEP with the patient and willingness to prescribe PrEP to her.

Results: We tested 2 models predicting providers (1) willingness to discuss and (2) willingness to prescribe PrEP, contingent on their racial attitudes. Providers who scored high on a modern racism measure were less willing to discuss and prescribe PrEP to the Black patient. These effects were mediated by provider perceptions of patients' abilities to adhere to PrEP, but not their expectations of risk compensatory behaviors.

Conclusions: Our findings highlight the importance of applying an intersectional lens in documenting the processes that exacerbate inequities in PrEP use. This study provides evidence to support the development of interventions that address the mechanisms that work to thwart optimal care.
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http://dx.doi.org/10.1097/QAI.0000000000002750DOI Listing
October 2021

Survival of bladder or renal cancer in patients with CHEK2 mutations.

PLoS One 2021 9;16(9):e0257132. Epub 2021 Sep 9.

Department of Genetics and Pathology, International Hereditary Cancer Center, Pomeranian Medical University, Szczecin, Poland.

Purpose: The purpose of this study was to compare the clinical characteristics and the survival of CHEK2 mutation positive and CHEK2 mutation negative patients diagnosed with bladder or kidney cancer.

Materials And Methods: 1016 patients with bladder and 402 cases with kidney cancer and 8302 controls were genotyped for four CHEK2 variants: 1100delC, del5395, IVS2+1G>A and I157T. Predictors of survival were determined among CHEK2 pathogenic variant carriers using the Cox proportional hazards model. The median follow-up was 17.5 years. Covariates included age (≤60; >61 years), sex (female; male), clinical characteristics (stage: TNM, grade, histopathological type), smoking status (non-smoking; smoking) and cancer family history (negative; positive).

Results: We found no impact of CHEK2 mutations on bladder or kidney cancer survival. However, we observed a possible increased survival in the subgroup of patients with stage T1 bladder cancer with CHEK2 mutations but this did not meet statistical significance (HR = 0.14; 95% CI 0.02-1.04; p = 0.055). Moreover, we observed that the missense mutations were more frequent in the low grade invasive bladder cancer patient group (OR = 7.9; 95% CI 1.50-42.1; p = 0.04) and in patients with bladder cancer with stage Ta (OR = 2.4; 95% CI 1.30-4.55; p = 0.006). The different results where missense mutations occurs less often we observed among patients with high grade invasive bladder cancer (OR = 0.12; 95% CI 0.02-0.66; p = 0.04) and those with stage T1 disease (OR = 0.2; 95% CI 0.07-0.76; p = 0.01). Our investigations revealed that any mutation in CHEK2 occurs more often among patients with stage Ta bladder cancer (OR = 2.0; 95% CI 1.19-3.47; p = 0.01) and less often in patients with stage T1 disease (OR = 0.31; 95% CI 0.12-0.78; p = 0.01). In the kidney cancer patients, truncating mutations were present more often in the group with clear cell carcinoma GII (OR = 8.0; 95% CI 0.95-67.7; p = 0.05). The 10-year survival for all CHEK2 mutation carriers with bladder cancer was 33% and for non-carriers 11% (p = 0.15). The 10-year survival for CHEK2 mutation carriers with kidney cancer 34% and for non-carriers 20% (p = 0.5).

Conclusion: CHEK2 mutations were not associated with any change in bladder or kidney cancer survival regardless of their age, sex, smoking status and family history. We observed a potentially protective effect of CHEK2 mutations on survival for patients with stage T1 bladder cancer. CHEK2 missense mutations were more common among patients with low grade invasive bladder cancer and in patients with stage Ta diease. The frequencies of the I157T CHEK2 pathogenic variant were less in patients with high grade invasive bladder cancer and those with stage T1 disease. Among patients with bladder cancer with stage Ta disease, the OR for any mutation in CHEK2 was 2.0 but for those with stage T1 disease, the OR was 0.3. We observed truncating CHEK2 mutations were associated with kidney cancer patients with GII clear cell carcinoma.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0257132PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8428549PMC
September 2021
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