546 research outputs found
Postcard: Old Settlers Day, August 13, 1908. Jewell City, Kansas
This colorized printed postcard features an illustration of a red hatchet on the left side of the card. Bundles of wheat and grain are colored yellow and written text is in the center of the card. The seal of the state and three cows are at the top of the card. Handwriting is on the back of the card.https://scholars.fhsu.edu/tj_postcards/1625/thumbnail.jp
Differences in the trophic ecology of micronekton driven by diel vertical migration.
Many species of micronekton perform diel vertical migrations (DVMs), which ultimately contributes to carbon export to the deep sea. However, not all micronekton species perform DVM, and the nonmigrators, which are often understudied, have different energetic requirements that might be reflected in their trophic ecology. We analyze bulk tissue and whole animal stable nitrogen isotopic compositions (δ 15N values) of micronekton species collected seasonally between 0 and 1250 m depth to explore differences in the trophic ecology of vertically migrating and nonmigrating micronekton in the central North Pacific. Nonmigrating species exhibit depth-related increases in δ 15N values mirroring their main prey, zooplankton. Higher variance in δ 15N values of bathypelagic species points to the increasing reliance of deeper dwelling micronekton on microbially reworked, very small suspended particles. Migrators have higher δ 15N values than nonmigrators inhabiting the epipelagic zone, suggesting the consumption of material during the day at depth, not only at night when they migrate closer to the surface. Migrating species also appear to eat larger prey and exhibit a higher range of variation in δ 15N values seasonally than nonmigrators, likely because of their higher energy needs. The dependence on material at depth enriched in 15N relative to surface particles is higher in migratory fish that ascend only to the lower epipelagic zone. Our results confirm that stark differences in the food habits and dietary sources of micronekton species are driven by vertical migrations
Predicting essential components of signal transduction networks: a dynamic model of guard cell abscisic acid signaling
Plants both lose water and take in carbon dioxide through microscopic
stomatal pores, each of which is regulated by a surrounding pair of guard
cells. During drought, the plant hormone abscisic acid (ABA) inhibits stomatal
opening and promotes stomatal closure, thereby promoting water conservation.
Here we synthesize experimental results into a consistent guard cell signal
transduction network for ABA-induced stomatal closure, and develop a dynamic
model of this process. Our model captures the regulation of more than forty
identified network components, and accords well with previous experimental
results at both the pathway and whole cell physiological level. Our analysis
reveals the novel predictions that the disruption of membrane depolarizability,
anion efflux, actin cytoskeleton reorganization, cytosolic pH increase, the
phosphatidic acid pathway or of K+ efflux through slowly activating K+ channels
at the plasma membrane lead to the strongest reduction in ABA responsiveness.
Initial experimental analysis assessing ABA-induced stomatal closure in the
presence of cytosolic pH clamp imposed by the weak acid butyrate is consistent
with model prediction. Our method can be readily applied to other biological
signaling networks to identify key regulatory components in systems where
quantitative information is limited.Comment: 17 pages, 8 figure
The role of crown architecture for light harvesting and carbon gain in extreme light environments assessed with a structurally realistic 3-D model
Concurrent Measurements of Oxygen and Carbon Dioxide Exchange during Lightflecks in Maize (Zea mays L.)
Determination of the Rate Limiting Step for Photosynthesis in a Nearly Isonuclear Rapeseed ( Brassica napus
Regulation of Photosynthetic Induction State in High- and Low-Light-Grown Soybean and Alocasia macrorrhiza (L.) G. Don
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