The nitrogen cycles for a red pine plantation and a mixed hardwood stand in central Massachusetts, USA, both of which were found to have high "resistance" to nutrient losses following disturbance, ...are presented. Both stands exhibit 1) slow rates of nitrogen cycling, 2) undetectable levels of nitrate and ammonia in lysimeter samples collected below the rooting zone, 3) small to negligible enrichment of nitrogen in throughfall compared with stemflow, and 4) no immobilization of nitrogen in decomposing leaf litter. All of these indicate a slow and tight nitrogen cycle and may also be indicative of "resistant" systems. Four major sinks for nitrogen within disturbed plots (created by trenching around a 1 × 4 m soil block) are analyzed; 1) denitrification, 2) leaching losses below the rooting zone and immobilization into 3) fine roots and 4) woody roots. In the hardwood stand these account for only 37 of 104$\text{kg}\text{N}\text{ha}^{-1}$mineralized and 66 of 90$\text{kg}\text{N}\text{ha}^{-1}$in the pines. An additional internal sink may be a delayed immobilization potential resulting from the lack of immobilization in decomposing leaf litter. This creates soil organic matter which may be used as a substrate for further immobilization when the removal of plant uptake increases nitrogen availability in soils. Additional immobilization may result from a switch from a decomposition system dominated by symbiotic mycorrhizal fungi to one dominated by free-living microbes.
Knowledge of carbon exchange between the atmosphere, land and the oceans is important, given that the terrestrial and marine environments are currently absorbing about half of the carbon dioxide that ...is emitted by fossil-fuel combustion. This carbon uptake is therefore limiting the extent of atmospheric and climatic change, but its long-term nature remains uncertain. Here the authors provide an overview of the current state of knowledge of global and regional patterns of carbon exchange by terrestrial ecosystems. Atmospheric carbon dioxide and oxygen data confirm that the terrestrial biosphere was largely neutral with respect to net carbon exchange during the 1980s, but became a net carbon sink in the 1990s. This recent sink can be largely attributed to northern extra tropical areas, and is roughly split between North America and Eurasia. Tropical land areas, however, were approximately in balance with respect to carbon exchange, implying a carbon sink that offset emissions due to tropical deforestation. The evolution of the terrestrial carbon sink is largely the result of changes in land use over time, such as regrowth on abandoned agricultural land and fire prevention, in addition to responses to environmental changes, such as longer growing seasons, and fertilization by carbon dioxide and nitrogen. Nevertheless, there remain considerable uncertainties as to the magnitude of the sink in different regions and the contribution of different processes.
We show that treatment of a panel of thyroid carcinoma cell lines naturally harboring the RET/PTC1 oncogene, with the RET kinase inhibitors PP1 and ZD6474, results in reversible G(1) arrest. This is ...accompanied by interruption of Shc and mitogen-activated protein kinase (MAPK) phosphorylation, reduced levels of G(1) cyclins, and increased levels of the cyclin-dependent kinase inhibitor p27Kip1 because of a reduced protein turnover. MAP/extracellular signal-regulated kinase 1/2 inhibition by U0126 caused G(1) cyclins down-regulation and p27Kip1 up-regulation as well. Forced expression of RET/PTC in normal thyroid follicular cells caused a MAPK- and proteasome-dependent down-regulation of p27Kip1. Reduction of p27Kip1 protein levels by antisense oligonucleotides abrogated the G(1) arrest induced by RET/PTC blockade. Therefore, in thyroid cancer, RET/PTC-mediated MAPK activation contributes to p27Kip1 deregulation. This pathway is implicated in cell cycle progression and in response to small molecule kinase inhibitors.
THE ELECTRO SENSOR COMPLEX (ESC) IS SOFTWARE THAT COMBINES THREE DEVICES USING BIOELECTRICAL IMPEDANCE, GALVANIC SKIN RESPONSE, AND SPECTROPHOTOMETRY: (1) ES-BC (Electro Sensor-Body Composition; LD ...Technology, Miami, FL) to assess body composition, (2) EIS-GS (Electro Interstitial Scan-Galvanic Skin; LD Technology) to predict autonomic nervous system activity, and (3) ES Oxi (Electro Sensor Oxi; LD Technology) to assess cardiac output. The objective of this study was to compare each to a standardized assessment: ES-BC to dual-energy X-ray absorptiometry (DXA), EIS-GS to heart rate variability, and ES Oxi to BioZ Dx Diagnostic System (BioZ Dx; SonoSite Inc, Bothell, WA).
The study was conducted in two waves. Fifty subjects were assessed for body composition and autonomic nervous system activity. Fifty-one subjects were assessed for cardiac output.
We found adequate relative and absolute agreement between ES-BC and DXA for fat mass (r = 0.97, P < 0.001) with ES-BC overestimating fat mass by 0.1 kg and for body fat percentage (r = 0.92, P < 0.001) with overestimation of fat percentage by 0.4%. For autonomic nervous system activity, we found marginal relative agreement between EIS-GS and heart rate variability by using EIS-GS as the predictor in a linear regression equation (adjusted R(2) = 0.56, P = 0.03). For cardiac output, adequate relative and absolute agreement was found between ES Oxi and BioZ Dx at baseline (r = 0.60, P < 0.001), after the first exercise stage (r = 0.79, P < 0.001), and after the second exercise stage (r = 0.86, P < 0.001). Absolute agreement was found at baseline and after both bouts of exercise; ES Oxi overestimated baseline and stage 1 exercise cardiac output by 0.3 L/minute and 0.1 L/minute, respectively, but exactly estimated stage 2 exercise cardiac output.
ES-BC and ES Oxi accurately assessed body composition and cardiac output compared to standardized instruments, whereas EIS-GS showed marginal predictive ability for autonomic nervous system activity. The ESC software managing the three devices would be useful to help detect complications related to metabolic syndrome, diabetes, and cardiovascular disease and to noninvasively and rapidly manage treatment follow-up.
Guillain-Barré syndrome is the most common polyneuropathy causing major disability and respiratory failure. Respiratory complications are the main cause of death. Improved respiratory care and new ...treatment strategies such as plasmaphoresis and immunoglobulin have been shown to improve outcome. We studied the course and outcome of 37 patients with Guillain-Barré syndrome who were admitted to a rehabilitation and respiratory care facility over a 10-year period. There were 21 males and 16 females with a mean age of 62+/-3 years. Fourteen patients developed respiratory failure requiring endotracheal intubation and mechanical ventilation. The mean duration of mechanical ventilation was 38+/-10 days. All patients were successfully liberated from the ventilator. However, 83 percent of the patients were moderately to severely disabled at the time of discharge. Thirteen out of 37 (35 percent) developed long-term disability. None of the patients died over the period of follow-up. These results indicate that early recognition and treatment of respiratory complications in Guillain-Barré syndrome could reduce the morbidity and mortality of this condition.
This article reviews the issues associated with the development of an E911 location network in light of the desire to leverage the E911 location network to provide universal non-cellular ...location-based services. The key issues are illustrated with a system originally developed for locating elderly patients with Alzheimer's disease.
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