This study presents a methods evaluation and intercalibration of active fluorescence-based measurements of the quantum yield (ϕ'ₚₛᵢᵢ) and absorption coefficient (aₚₛᵢᵢ) of photosystem II (PSII) photochemistry. Measurements of ϕ'ₚₛᵢᵢ, aₚₛᵢᵢ, and irradiance (E) can be scaled to derive photosynthetic electron transport rates (Pₑ), the process that fuels phytoplankton carbon fixation...
Various ocean-climate models driven by increased greenhouse gases and higher temperatures predict a decline in oceanic dissolved oxygen (DO) as a result of greater stratification, reduced ventilation below the thermocline, and decreased solubility at higher temperatures. Since spreading of low oxygen waters is underway and predicted to increase, understanding impacts...
Brazil's economic strategy has shifted hesitatingly during the last several decades from one of producer protection to trade competitiveness. Exploiting the variations these shifts have afforded, we use a sequence of decennial agricultural censuses to examine Brazilian policy implications for agricultural competitiveness and efficiency. Total factor productivity is decomposed into...
1. Ecosystem invasibility is determined by combinations of environmental variables, invader attributes, disturbance regimes, competitive abilities of resident species and evolutionary history between residents and disturbance regimes. Understanding the relative importance of each factor is critical to limiting future invasions and restoring ecosystems.
2. We investigated factors potentially controlling Bromus...
In June of 2013, the U.S. Fish and Wildlife Service proposed removing gray wolves (Canis lupus, Linnaeus) from Endangered Species Act (ESA) protections throughout the conterminous United States. The proposed rule depends on a definition of endangerment that is inconsistent with the legislative history and historical implementation of the ESA,...
Objectives:
To examine the association between kidney function and all-cause mortality in octogenarians.
Design
Retrospective analysis of prospectively collected data.
Setting:
Community.
Participants:
Serum creatinine and cystatin C were measured in 1,053 Cardiovascular Health Study (CHS) All Stars participants.
Measurements:
Estimated glomerular filtration rate (eGFR) was determined using the Chronic...
Nearshore hypoxia along the coast of Oregon and Washington is a seasonal phenomenon that has generated concern among scientists studying this temperate upwelling ecosystem. These waters are affected by coastal upwelling-induced hypoxia mainly during late summer and fall, but the effects of low oxygen levels on fish and invertebrate communities,...
Pathogens may alter their hosts, which consequently increases transmission efficiency by vectors. We examined the effects of Raspberry leaf mottle virus [RLMV; Closterovirus (Closteroviridae)] and Raspberry latent virus [RpLV; Reovirus (Reoviridae)], alone and in a co-infection in raspberry, Rubus
idaeus L. (Rosaceae) cv. Meeker, on the behavior and performance of...
We investigated 32 net primary productivity (NPP) models by assessing skills to reproduce integrated NPP in the Arctic Ocean. The models were provided with two sources each of surface chlorophyll-a concentration (chlorophyll), photosynthetically available radiation (PAR), sea surface temperature (SST), and mixed-layer depth (MLD). The models were most sensitive to...
The influence of varying horizontal and vertical stratification in the upper layer ( inline image m) associated with riverine waters and seasonal atmospheric fluxes on coastal near-inertial currents is investigated with remotely sensed and in situ observations of surface and subsurface currents and realistic numerical model outputs off the coast...