Now showing items 51-60 of 120
Sources of reactive nitrogen affecting ecosystems in Latin America and the Caribbean: current trends and future perspectives
(Kluwer Academic Publishers; Springer Science+Business Media, Inc., 2006-04-06)
While the amount of reactive nitrogen circulating at the global level has increased markedly in the last century, the effects of this increase are largely seen at the regional level due to interacting ecological and ...
A parameter sensitivity methodology in the context of HIV delay equation models
(Springer-Verlag; Springer-Verlag Berlin Heidelberg, 2005-06)
A sensitivity methodology for nonlinear delay systems arising in one class of cellular HIV infection models is presented. Theoretical foundations for a typical sensitivity investigation and illustrative computations are given.
Anthropogenic N deposition and the fate of 15 NO 3 − in a northern hardwood ecosystem
(Kluwer Academic Publishers; Springer Science+Business Media, 2004-06)
Human activity has substantially increased atmospheric NO 3 − deposition in many regions of the Earth, which could lead to the N saturation of terrestrial ecosystems. Sugar maple ( Acer saccharum Marsh.) dominated northern ...
Production and export of dissolved C in arctic tundra mesocosms: the roles of vegetation and water flow
(Kluwer Academic Publishers; Springer Science+Business Media, 2002-09)
To better understand carbon (C) cycling in arctic tundra we measureddissolved C production and export rates in mesocosms of three tundra vegetationtypes: tussock, inter-tussock and wet sedge. Three flushing frequencies ...
Carbon dioxide and water vapor exchange in a warm temperate grassland
(Springer-Verlag, 2004-01)
Grasslands cover about 40% of the ice-free global terrestrial surface, but their contribution to local and regional water and carbon fluxes and sensitivity to climatic perturbations such as drought remains uncertain. Here, ...
Potent cytotoxins produced by a microbial symbiont protect host larvae from predation
(Springer-Verlag, 2004-03)
Larvae of the sessile marine invertebrate Bugula neritina (Bryozoa) are protected by an effective chemical defense. From the larvae, we isolated three bryostatin-class macrocyclic polyketides, including the novel bryostatin ...
A Comparative Study of Human Muscle and Brain Creatine Kinases Expressed in Escherichia coli
(Kluwer Academic Publishers-Plenum Publishers; Plenum Publishing Corporation ; Springer Science+Business Media, 2000-01)
We report the expression of the human muscle (CK-MM) and brain (CK-BB) creatine kinases in Escherichia coli . The proteins have been purified to apparent homogeneity and several of their physical and kinetic properties ...
Responses of bullfrog tadpoles to hypoxia and predators
(Springer-Verlag, 2000-10)
Low dissolved oxygen concentrations present numerous challenges for non-air-breathing aquatic organisms. Amphibian larvae and their predators can respond to oxygen levels by altering their behavior and physiology, but the ...
Identification of members of the Wnt signaling pathway in the embryonic pituitary gland
(Springer-Verlag; Springer-Verlag New York Inc., 2001-11)
Prop1 is one of several transcription factors important for the development of the pituitary gland. Downstream targets of PROP1 and other critical pituitary transcription factors remain largely unknown. We have generated ...
Lingual deficits in neurotrophin double knockout mice
(Kluwer Academic Publishers; Springer Science + Business Media, Inc., 2004-12)
Brain-derived neurotrophic factor (BDNF) and Neurotrophin 3 (NT-3) are members of the neurotrophin family and are expressed in the developing and adult tongue papillae. BDNF null-mutated mice exhibit specific impairments ...