Water and Nutrient Outflow From Contrasting Lodgepole Pine Forests in Wyoming

Factors affecting water and nutrient outflow beyond the rooting zone were studied during a 3—yr period, using data from eight contrasting stands of lodgepole pine (Pinus contorta ssp. latifolia) forest in southeastern Wyoming and the output of a hydrologic simulation model (H2OTRANS) based on tree physiology. Nutrient outflow during a specific time period was estimated by multiplying simulated water outflow times element concentrations in the soil solution, the latter determined from samples collected periodically near the bottom of the rooting zone. Estimates of actual evapotranspiration (ET) for the period from early spring to late fall ranged from 21 to 53 cm, which was 33—95% (x = 73%) of total annual precipitation. For all stands and years, transpiration accounted for 50—61% of ET, and 9—44% of the transpiration occurred during the spring drainage period (vernal transpiration, VT). Estimated VT and outflow varied considerably among the stands, with VT accounting for 4—20% of the snow water. Outflow occurred only during the snow melt period and accounted for 0—80% of the snow water. Snow water equivalent varied annually by 300% or more. Nutrient outflow from the different stands also varied greatly. Ratios between simulated annual outflow and atmospheric inputs (bulk precipitation) were consistently \u3e1.0 for Ca, Na, and Mg; were consistently \u3c1.0 for N; and ranged from 0.3 to 2.0 for P and from 0.2 to 3.3 for K. Much of the variability in water and nutrient outflow can be attributed to the degree of biotic control, with water outflow affected by a different combination of factors than nutrient outflow. H2OTRANS was used to simulate the effects on outflow of different snow water equivalents and different total leaf areas. One result of the simulations was that nitrogen appears to be retained even at the highest levels of water outflow. Another was that increases in water outflow following reduction in leaf area were proportional to the leaf area removed. The results indicate that stands differing in site or habitat type experience different rates of water and element losses at different times during the snow melt season, and contribute differentially to streamwater quality and hydrograph shape. Factors affecting outflow are discussed in the context of successional trends, common perturbations including timber harvest, and hypotheses pertaining to nutrient conservation in terrestrial ecosystems. Nutrient retention in the snow—dominated lodgepole pine ecosystem appears to be primarily dependent on evergreen leaf area, duration of the VT period, and high carbon/nutrient ratios of the forest floor. Net losses of limiting nutrients probably occur primarily in pulses after abiotic perturbations such as fire

Effects of Training Intensity on Locomotor Performance in Individuals With Chronic Spinal Cord Injury: A Randomized Crossover Study

Background. Many physical interventions can improve locomotor function in individuals with motor incomplete spinal cord injury (iSCI), although the training parameters that maximize recovery are not clear. Previous studies in individuals with other neurologic injuries suggest the intensity of locomotor training (LT) may positively influence walking outcomes. However, the effects of intensity during training of individuals with iSCI have not been tested. Objective. The purpose of this pilot, blinded-assessor randomized trial was to evaluate the effects of LT intensity on walking outcomes in individuals with iSCI. Methods. Using a crossover design, ambulatory participants with iSCI \u3e1 year duration performed either high- or low-intensity LT for ≤20 sessions over 4 to 6 weeks. Four weeks following completion, the training interventions were alternated. Targeted intensities focused on achieving specific ranges of heart rate (HR) or ratings of perceived exertion (RPE), with intensity manipulated by increasing speeds or applying loads. Results. Significantly greater increases in peak treadmill speeds (0.18 vs 0.02 m/s) and secondary measures of metabolic function and overground speed were observed following high- versus low-intensity training, with no effects of intervention order. Moderate to high correlations were observed between differences in walking speed or distances and differences in HRs or RPEs during high- versus low-intensity training. Conclusion. This pilot study provides the first evidence that the intensity of stepping practice may be an important determinant of LT outcomes in individuals with iSCI. Whether such training is feasible in larger patient populations and contributes to improved locomotor outcomes deserves further consideration

Transpiration From 100-yr-old Lodgepole Pine Forests Estimated with Whole-Tree Potometers

Whole—tree potometers were used to estimate transpiration from two contrasting stands of 100—yr—old lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) forest growing on the same site in southeastern Wyoming. Although one stand had nearly seven times as any trees per hectare and 29% less biomass, both stands had nearly identical leaf area indices (7.3 and 7.1) and clear—day transpiration rates (3.3 and 3.4 mm/d). Individual tree basal area and maximum observed 24—h uptake were highly correlated, with the largest trees (20—26 cm dbh) transpiring 40—44 L on clear days in early summer. Maximum observed hourly uptake for the larger trees was 2.5—3.5 L, with total nighttime uptake being about 12% of 25—h uptake. On overcast days potometer uptake was reduced by 30—44%; during rainy periods uptake was reduced to nearly zero. The results are compared to data obtained with different methods by other investigators, with the conclusion that whole—tree potometers can be a useful tool for studies on tree water relations and for estimating short—term forest transpiration when leaf water potential is not limiting leaf conductance

Laboratory evaluation of the effect of nitric acid uptake on frost point hygrometer performance

Chilled mirror hygrometers (CMH) are widely used to measure water vapour in the troposphere and lower stratosphere from balloon-borne sondes. Systematic discrepancies among in situ water vapour instruments have been observed at low water vapour mixing ratios (<5 ppm) in the upper troposphere and lower stratosphere (UT/LS). Understanding the source of the measurement discrepancies is important for a more accurate and reliable determination of water vapour abundance in this region. We have conducted a laboratory study to investigate the potential interference of gas-phase nitric acid (HNO<sub>3</sub>) with the measurement of frost point temperature, and consequently the water vapour mixing ratio, determined by CMH under conditions representative of operation in the UT/LS. No detectable interference in the measured frost point temperature was found for HNO<sub>3</sub> mixing ratios of up to 4 ppb for exposure times up to 150 min. HNO<sub>3</sub> was observed to co-condense on the mirror frost, with the adsorbed mass increasing linearly with time at constant exposure levels. Over the duration of a typical balloon sonde ascent (90–120 min), the maximum accumulated HNO<sub>3</sub> amounts were comparable to monolayer coverage of the geometric mirror surface area, which corresponds to only a small fraction of the actual frost layer surface area. This small amount of co-condensed HNO<sub>3</sub> is consistent with the observed lack of HNO<sub>3</sub> interference in the frost point measurement because the CMH utilizes significant reductions (>10%) in surface reflectivity by the condensate to determine H<sub>2</sub>O

On the Role of Penning Ionization in Photoassociation Spectroscopy

We study the role of Penning ionization on the photoassociation spectra of He(^3S)-He(^3S). The experimental setup is discussed and experimental results for different intensities of the probe laser are shown. For modelling the experimental results we consider coupled-channel calculations of the crossing of the ground state with the excited state at the Condon point. The coupled-channel calculations are first applied to model systems, where we consider two coupled channels without ionization, two coupled channels with ionization, and three coupled channels, for which only one of the excited states is ionizing. Finally, coupled-channel calculations are applied to photoassociation of He(^3S)-He(^3S) and good agreement is obtained between the model and the experimental results.Comment: 14 pages, 18 figures, submitted to the special issue on Cold Molecules of J. Phys.

U.S. GLOBAL CHANGE RESEARCH PROGRAM CLIMATE SCIENCE SPECIAL REPORT (CSSR)

Fifth-Order Draft Table of Contents Front Matter About This Report........................................................................................ 1 Guide to the Report......................................................................................4 Executive Summary ................................................................................... 12 Chapters 1. Our Globally Changing Climate .......................................................... 38 2. Physical Drivers of Climate Change ................................................... 98 3. Detection and Attribution of Climate Change .................................... 160 4. Climate Models, Scenarios, and Projections .................................... 186 5. Large-Scale Circulation and Climate Variability ................................ 228 6. Temperature Changes in the United States ...................................... 267 7. Precipitation Change in the United States ......................................... 301 8. Droughts, Floods, and Hydrology ......................................................... 336 9. Extreme Storms ....................................................................................... 375 10. Changes in Land Cover and Terrestrial Biogeochemistry ............ 405 11. Arctic Changes and their Effects on Alaska and the Rest of the United States..... 443 12. Sea Level Rise ....................................................................................... 493 13. Ocean Acidification and Other Ocean Changes .............................. 540 14. Perspectives on Climate Change Mitigation .................................... 584 15. Potential Surprises: Compound Extremes and Tipping Elements .......... 608 Appendices A. Observational Datasets Used in Climate Studies ............................. 636 B. Weighting Strategy for the Fourth National Climate Assessment ................ 642 C. Detection and Attribution Methodologies Overview ............................ 652 D. Acronyms and Units ................................................................................. 664 E. Glossary ...................................................................................................... 66

U.S. GLOBAL CHANGE RESEARCH PROGRAM CLIMATE SCIENCE SPECIAL REPORT (CSSR)

Fifth-Order Draft Table of Contents Front Matter About This Report........................................................................................ 1 Guide to the Report......................................................................................4 Executive Summary ................................................................................... 12 Chapters 1. Our Globally Changing Climate .......................................................... 38 2. Physical Drivers of Climate Change ................................................... 98 3. Detection and Attribution of Climate Change .................................... 160 4. Climate Models, Scenarios, and Projections .................................... 186 5. Large-Scale Circulation and Climate Variability ................................ 228 6. Temperature Changes in the United States ...................................... 267 7. Precipitation Change in the United States ......................................... 301 8. Droughts, Floods, and Hydrology ......................................................... 336 9. Extreme Storms ....................................................................................... 375 10. Changes in Land Cover and Terrestrial Biogeochemistry ............ 405 11. Arctic Changes and their Effects on Alaska and the Rest of the United States..... 443 12. Sea Level Rise ....................................................................................... 493 13. Ocean Acidification and Other Ocean Changes .............................. 540 14. Perspectives on Climate Change Mitigation .................................... 584 15. Potential Surprises: Compound Extremes and Tipping Elements .......... 608 Appendices A. Observational Datasets Used in Climate Studies ............................. 636 B. Weighting Strategy for the Fourth National Climate Assessment ................ 642 C. Detection and Attribution Methodologies Overview ............................ 652 D. Acronyms and Units ................................................................................. 664 E. Glossary ...................................................................................................... 66

Investigating knowledge management factors affecting Chinese ICT firms performance: An integrated KM framework

This is an Author's Accepted Manuscript of an article published in the Journal of Information Systems Management, 28(1), 19 - 29, 2011, copyright Taylor & Francis, available online at: http://www.tandfonline.com/10.1080/10580530.2011.536107.This article sets out to investigate the critical factors of Knowledge Management (KM) which are considered to have an impact on the performance of Chinese information and communication technology (ICT) firms. This study confirms that the cultural environment of an enterprise is central to its success in the context of China. It shows that a collaborated, trusted, and learning environment within ICT firms will have a positive impact on their KM performance

OH in the Tropical Upper Troposhere and Its Relationships to Solar Radiation and Reactive Nitrogen

In situ measurements of [OH], [HO2] (square brackets denote species concentrations), and other chemical species were made in the tropical upper troposphere (TUT). [OH] showed a robust correlation with solar zenith angle. Beyond this dependence, however, [HOx] ([OH] + [HO2]) only weakly responds to variations in its source and sink species. For example, at a given SZA, [HOx] was broadly independent of the product of [O3] and [H2O]. This suggests that [OH] is heavily buffered in the TUT. One important exception to this result is found in regions with very low [O3], [NO], and [NOy], where [OH] is highly suppressed, pointing to the critical role of NO in sustaining OH in the TUT

Contemporary Issues in Translantic Relations

This report summarises the interdisciplinary seminar hosted by the Jean Monnet Chair in Transatlantic Relations at City Law School and the Institute for the Study of European Law (ISEL). The event consisted of three sessions: The Transatlantic Relationship; Transatlantic Defence, Security and Civil Liberties; Transatlantic and Global Trade. It examined topical issues in transatlantic relations across a range of subjects and issues, from trade, security and data, to defence. The seminar reflected upon the state of the art in transatlantic relations, with speakers from a broad variety of disciplines and practice. It considered inter alia: How should we understand the future of ‘American First’ at the end of the Trump Presidency? What is the current state of the US-Sino tech war and what are its implications for EU-US relations? How do UK-US relations impact upon this equation, in light of the Huawei 5G affair? What is the future of the EU-UK-US triangle in international security, where the EU loses the heft of one of its largest members? Will the UK increasingly align in sectoral fields to the US? What do the negotiation objectives of the EU-US and UK-US indicate to us about the future of the special partnerships? With the world’s largest sanctions regimes, the EU and US will pose a challenge for the UK to alignment purposes- will it inevitably be the EU first? What are its implications for a more significant FTA between the respective parties? How does the rise of the EU as a global data actor influence contemporary politics? Has the US succeeded in taming the global mobility of its social media giants through taxation threats? How does a multilateralist such as the EU deal with the future of American First after the next US election and the development of the uncertain path of Global Britain? Does Churchill’s call for a United States of Europe with the UK outside but closely aligned within the Commonwealth of Nations have any resonance going forward? In any field at all? What developments in the breakdown of the WTO DS system can occur with the aid of the EU, US and UK? Is the US sincere about its reform? Can Global Britain survive a shift outside of the EU without a WTO DS