5 results on '"Smith, Kenneth"'
Search Results
2. Forest carbon uptake as influenced by snowpack and length of photosynthesis season in seasonally snow-covered forests of North America.
- Author
-
Yang, Julia C., Bowling, David R., Smith, Kenneth R., Kunik, Lewis, Raczka, Brett, Anderegg, William R.L., Bahn, Michael, Blanken, Peter D., Richardson, Andrew D., Burns, Sean P., Bohrer, Gil, Desai, Ankur R., Arain, M. Altaf, Staebler, Ralf M., Ouimette, Andrew P., Munger, J. William, and Litvak, Marcy E.
- Subjects
- *
SEASONS , *DECIDUOUS forests , *FOREST productivity , *RAINFALL , *PHOTOSYNTHESIS , *SNOW cover , *PLANT phenology - Abstract
• Patterns of summer forest productivity were examined in the context of winter snow and summer rain. • The GPP season was longer in years with earlier snowmelt. • Total GPP was higher for a longer GPP season in sites with wetter summer climate. • Total GPP was lower for a longer GPP season in sites with drier summer climate. • These patterns were weaker in forests with snow as a higher annual fraction of precipitation. Seasonal snow cover is important in shaping ecosystem carbon uptake across many regions of the world, however forest responses to projected declines in snowpack remain uncertain. We studied the response of forest gross primary productivity (GPP) during the photosynthetically active season to interannual and spatial variability in snow water equivalent (SWE), timing of snowmelt, and length of the active season. We combined carbon flux and weather data from 14 temperate deciduous and evergreen forests in the US and southeast Canada with SWE and precipitation from the Snow Data Assimilation System to test these hypotheses: 1) earlier snowmelt leads to a longer active season; 2) a longer active season is associated with higher total GPP, and 3) GPP during the active season is dependent on peak SWE and timing of snowmelt the previous winter. Regression and correlation analyses did not reveal meaningful environmental predictors of interannual variability in GPP, so linear mixed effects models were used to analyze broader scale spatiotemporal patterns. We found that active season length was negatively correlated with total active season GPP in forests with drier summers on average (based on mean annual summer climatic water deficit), but positively correlated in areas with typically wetter summers. The magnitude of these effects decreased at forests with a higher percentage of annual precipitation falling as snow. Our results showed that the capacity for plants to gain more carbon during a longer active season appears to be dependent on soil water status determined by long-term climate, rather than interannual fluctuations in weather. We found no evidence that the magnitude of total snowfall or peak SWE had a legacy effect on subsequent active season GPP. Finally, we highlight that there was large interannual variability both within and between sites that was not well explained by seasonal climate or phenology. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
3. A new fight for London's elms.
- Author
-
Smith, Kenneth J.
- Subjects
- *
ELM - Abstract
Presents the planting of the Liberty elm near the site of the Simcoe elm. Research at the Elm Research Institute in Harrisville, New Hampshire, resulting in a disease-resistant elm; Tribute to John Graves Simcoe, first lieutenant governor of Ontario; Naming of the city's biggest and oldest elm as Simcoe elm in 1956.
- Published
- 1993
4. Many shades of grey in ethical behaviour.
- Author
-
Smith, Kenneth
- Subjects
VALUATION ,VALUATION of real property ,REAL estate appraisers ,APPRAISERS ,ETHICS - Abstract
The article considers the ethical aspects of appraisal reports that conform to the Canadian Uniform Standards of Professional Appraisal Practice set by the Appraisal Institute of Canada (AIC). The standards define the term reasonable appraiser as an individual who offers appraisal review as well as consulting services within an acceptable expertise and skill. The author states that this term is commonly used by courts to identify if a person has breached the standard of care.
- Published
- 2010
5. Very early hypothermia induction in patients with severe brain injury (the National Acute Brain Injury Study: Hypothermia II): a randomised trial
- Author
-
Clifton, Guy L, Valadka, Alex, Zygun, David, Coffey, Christopher S, Drever, Pamala, Fourwinds, Sierra, Janis, L Scott, Wilde, Elizabeth, Taylor, Pauline, Harshman, Kathy, Conley, Adam, Puccio, Ava, Levin, Harvey S, McCauley, Stephen R, Bucholz, Richard D, Smith, Kenneth R, Schmidt, John H, Scott, James N, Yonas, Howard, and Okonkwo, David O
- Subjects
- *
HYPOTHERMIA , *BRAIN injuries , *HEALTH outcome assessment , *PHYSIOLOGICAL effects of cold temperatures , *CLINICAL trials - Abstract
Summary: Background: The inconsistent effect of hypothermia treatment on severe brain injury in previous trials might be because hypothermia was induced too late after injury. We aimed to assess whether very early induction of hypothermia improves outcome in patients with severe brain injury. Methods: The National Acute Brain Injury Study: Hypothermia II (NABIS: H II) was a randomised, multicentre clinical trial of patients with severe brain injury who were enrolled within 2·5 h of injury at six sites in the USA and Canada. Patients with non-penetrating brain injury who were 16–45 years old and were not responsive to instructions were randomly assigned (1:1) by a random number generator to hypothermia or normothermia. Patients randomly assigned to hypothermia were cooled to 35°C until their trauma assessment was completed. Patients who had none of a second set of exclusion criteria were either cooled to 33°C for 48 h and then gradually rewarmed or treated at normothermia, depending upon their initial treatment assignment. Investigators who assessed the outcome measures were masked to treatment allocation. The primary outcome was the Glasgow outcome scale score at 6 months. Analysis was by modified intention to treat. This trial is registered with ClinicalTrials.gov, NCT00178711. Findings: Enrolment occurred from December, 2005, to June, 2009, when the trial was terminated for futility. Follow-up was from June, 2006, to December, 2009. 232 patients were initially randomised a mean of 1·6 h (SD 0·5) after injury: 119 to hypothermia and 113 to normothermia. 97 patients (52 in the hypothermia group and 45 in the normothermia group) did not meet any of the second set of exclusion criteria. The mean time to 35°C for the 52 patients in the hypothermia group was 2·6 h (SD 1·2) and to 33°C was 4·4 h (1·5). Outcome was poor (severe disability, vegetative state, or death) in 31 of 52 patients in the hypothermia group and 25 of 56 in the normothermia group (relative risk [RR] 1·08, 95% CI 0·76–1·53; p=0·67). 12 patients in the hypothermia group died compared with eight in the normothermia group (RR 1·30, 95% CI 0·58–2·52; p=0·52). Interpretation: This trial did not confirm the utility of hypothermia as a primary neuroprotective strategy in patients with severe traumatic brain injury. Funding: National Institute of Neurological Disorders and Stroke. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.