The Arctic plant aboveground biomass synthesis dataset

Abstract Plant biomass is a fundamental ecosystem attribute that is sensitive to rapid climatic changes occurring in the Arctic. Nevertheless, measuring plant biomass in the Arctic is logistically challenging and resource intensive. Lack of accessible field data hinders efforts to understand the amount, composition, distribution, and changes in plant biomass in these northern ecosystems. Here, we present The Arctic plant aboveground biomass synthesis dataset, which includes field measurements of lichen, bryophyte, herb, shrub, and/or tree aboveground biomass (g m−2) on 2,327 sample plots from 636 field sites in seven countries. We created the synthesis dataset by assembling and harmonizing 32 individual datasets. Aboveground biomass was primarily quantified by harvesting sample plots during mid- to late-summer, though tree and often tall shrub biomass were quantified using surveys and allometric models. Each biomass measurement is associated with metadata including sample date, location, method, data source, and other information. This unique dataset can be leveraged to monitor, map, and model plant biomass across the rapidly warming Arctic

Case Study of the U.S. Army

Naval Postgraduate School Acquisition Research Progra

Case study of the U.S. Army's should-cost management implementation

On May 22, 2009, President Barack Obama signed into law the Weapons Systems Acquisition Reform Act (WSARA). The intent of this law is to reform acquisition processes, control unsustainable cost growth, and make programs more affordable. In 2010, despite WSARA, program cost, schedule overruns, and less-than-desirable performance were still prevalent in DoD acquisition. In response, Ashton Carter, Under Secretary of Defense for Acquisition, Technology, and Logistics (USD[AT&L]), issued his Better Buying Power (BBP) memorandum directing the implementation of Should-Cost Management (SCM). In April 2011, Carter issued an additional directive that should-cost estimates would be required for all acquisition category (ACAT) programs and that SCM initiative progress would be briefed at every milestone review. In November 2012, Frank Kendall, Carters successor, issued an update to the original BBP initiative (BBPi), reinforcing the success of the BBPi. Kendalls update incorporated lessons learned from two years of implementation and feedback from the acquisition workforce. Our case study examines how the Army has implemented SCM as part of the BBPi. We analyze actions taken from the program manager to the Army acquisition executive using Program Executive Office (PEO) Aviation as our case study focus.http://archive.org/details/casestudyofusarm1094538900Major, United States ArmyApproved for public release; distribution is unlimited

Case Study of the U.S. Armys Should-cost Management Implementation

Annual Acquisition Research SymposiumNaval Postgraduate School Naval Postgraduate School Acquisition Research Progra

Pancreatitis in cystic fibrosis: Presentation, medical and surgical management, and the impact of modulator therapies

Patients with Cystic Fibrosis (CF) are at increased risk of acute (AP) and chronic (CP) pancreatitis, and their complications. The extent of remaining healthy pancreatic parenchyma determines the risk of developing future episodes of pancreatitis, as well as pancreatic exocrine or endocrine insufficiency. Pancreatitis may be the presenting symptom of CF, and genetic testing is especially important in pediatrics. AP and recurrent AP are managed with intravenous fluid hydration and pain control, in addition to early refeeding and treatment of complications. With the use of modulator therapy in CF, pancreatic function may be restored to some extent. CP related pain is managed with analgesics and neuromodulators, with surgery if indicated in specific situations including TPIAT as a possible type of surgical intervention. Long-term sequelae of CP in patients with CF include exocrine pancreatic insufficiency treated with pancreatic enzyme replacement therapy, fat-soluble vitamin deficiencies and associated metabolic complications such as bone disease/osteoporosis, pancreatogenic diabetes, and less commonly, pancreatic cancer. We review the presentation and etiologies of pancreatitis in CF patients as well as the management of AP and CP primarily in children

Increased nutrient availability speeds up permafrost development, while goose grazing slows it down in a Canadian High Arctic wetland

Abstract 1. It is of prime importance to understand feedbacks due to the release of carbon (C) stored in permafrost soils (permafrost-climate feedback) and direct impacts of climatic variations on permafrost dynamics therefore received considerable attention. However, indirect effects of global change, such as the variation in soil nutrient availability and grazing pressure, can alter soil and surface properties of the Arctic tundra, with the potential to modify soil heat transfers toward the permafrost and impact resilience of Arctic ecosystems. 2. We determined the potential of nutrients availability and grazing to alter soil energy balance using a 16-year split-plot experiment crossing fertilization at different doses of nitrogen (N) and phosphorus (P) with protection from goose grazing. Moss biomass and some determinants of the surface energy budget (leaf area index (LAI), dead vascular plant biomass and albedo) were quantified and active layer thaw depth repeatedly measured during three growing seasons. We measured soil physical properties and thermal conductivity and used a physical model to link topsoil organic accumulation processes to heat transfer. Fertilization increased LAI and albedo, whereas grazing decreased dead vascular plant biomass and albedo. 3. Fertilization increased organic accumulation at the top of the soil leading to drier and more porous topsoil, whereas grazing increased water content of topsoil. As a result, topsoil thermal conductivity was higher in grazed plots than in ungrazed ones. Including these properties into a simulation model, we showed that, after 16 years, nutrient addition tended to shallow the active layer whereas grazing deepened mean July active layer by 3.3 cm relative to ungrazed subplots. As a result of OM accumulation at the surface, fertilization increased permafrost vertical aggradation rate by almost an order of magnitude (up to 5 mm‧year-1 instead of 0.7 mm‧year-1), whereas grazing slowed down permafrost aggradation by reducing surface uprising and deepening thaw depth. 4. Synthesis: We demonstrated that long-term grazing and N and P addition, through their impact on vegetation and soil properties have the potential to impact permafrost dynamics to the same extent as contemporary temperature increase in High Arctic polygonal wetlands

The Arctic plant aboveground biomass synthesis dataset

Plant biomass is a fundamental ecosystem attribute that is sensitive to rapid climatic changes occurring in the Arctic. Nevertheless, measuring plant biomass in the Arctic is logistically challenging and resource intensive. Lack of accessible field data hinders efforts to understand the amount, composition, distribution, and changes in plant biomass in these northern ecosystems. Here, we present The Arctic plant aboveground biomass synthesis dataset, which includes field measurements of lichen, bryophyte, herb, shrub, and/or tree aboveground biomass (g m−2) on 2,327 sample plots from 636 field sites in seven countries. We created the synthesis dataset by assembling and harmonizing 32 individual datasets. Aboveground biomass was primarily quantified by harvesting sample plots during mid- to late-summer, though tree and often tall shrub biomass were quantified using surveys and allometric models. Each biomass measurement is associated with metadata including sample date, location, method, data source, and other information. This unique dataset can be leveraged to monitor, map, and model plant biomass across the rapidly warming Arctic