Stepping On Fall Prevention Project

Background: Falls are a major problem in the United States among the older adult population and provide opportunity for community outreach via student-led physical therapy projects. Objective: The purpose of this project was to investigate the relationship between fall related outcome measures and questionnaires with the completion of the Stepping On Fall Prevention program along with evaluating the benefits of Physical Therapy student development with participation in service learning projects. Methods: The research quantified the fall risk of 13 participants with assessment of: gait speed (Timed Up and Go), lower extremity strength (30-Second Chair Stand), balance (4-Stage Balance Test), and psychological factors (Stay Independent Questionnaire, Falls Efficacy Scale-International, and Geriatric Depression Scale). Results: Of the functional measures, significant improvements were observed in the Timed up and Go (TUG) (∆1.72s ± 1.66, p=0.003), the 30-second chair stand (∆4.54 ± 4.27, p= 0.002), Stage 4 of the 4-Stage Balance Test (∆3.37s ± 3.26, p= 0.003), and the Stay Independent questionnaire (∆1.77 ± 2.52, p=0.026). Conclusion: Stepping On demonstrated improvements in gait speed, strength, and balance. These improvements allow older adults to improve their overall safety in both their own homes and the community. More research is needed to evaluate the psychological benefits of completing Stepping On. Furthermore, service learning project opportunities should become more of a standard practice across physical therapy programs

The contribution of terrestrial sources and sinks to trends in the seasonal cycle of atmospheric carbon dioxide

We characterized decadal changes in the amplitude and shape of the seasonal cycle of atmospheric CO_2 with three kinds of analysis. First, we calculated the trends in the seasonal cycle of measured atmospheric CO_2 at observation stations in the National Oceanic and Atmospheric Administration Climate Monitoring and Diagnostic Laboratory network. Second, we assessed the impact of terrestrial ecosystems in various localities on the mean seasonal cycle of CO_2 at observation stations using the Carnegie‐Ames‐Stanford Approach terrestrial biosphere model and the Goddard Institute for Space Studies (GISS) atmospheric tracer transport model. Third, we used the GISS tracer model to quantify the contribution of terrestrial sources and sinks to trends in the seasonal cycle of atmospheric CO_2 for the period 1961–1990, specifically examining the effects of biomass burning, emissions from fossil fuel combustion, and regional increases in net primary production (NPP). Our analysis supports results from previous studies that indicate a significant positive increase in the amplitude of the seasonal cycle of CO_2 at Arctic and subarctic observation stations. For stations north of 55°N the amplitude increased at a mean rate of 0.66% yr^(−1) from 1981 to 1995. From the analysis of ecosystem impacts on the mean seasonal cycle we find that tundra, boreal forest, and other northern ecosystems are responsible for most of the seasonal variation in CO_2 at stations north of 55°N. The effects of tropical biomass burning on trends in the seasonal cycle are minimal at these stations, probably because of strong vertical convection in equatorial regions. From 1981 to 1990, fossil fuel emissions contributed a trend of 0.20% yr^(−1) to the seasonal cycle amplitude at Mauna Loa and less than 0.10% yr^(−1) at stations north of 55°N. To match the observed amplitude increases at Arctic and subarctic stations with NPP increases, we find that north of 30°N a 1.7 Pg C yr^(−1) terrestrial sink would be required. In contrast, over regions south of 30°N, even large NPP increases and accompanying terrestrial sinks would be insufficient to account for the increase in high‐latitude amplitudes

Substrate limitations for heterotrophs: Implications for models that estimate the seasonal cycle of atmospheric CO_2

We examine the sensitivity of the seasonal cycle of heterotrophic respiration to model estimates of litterfall seasonality, herbivory, plant allocation, tissue chemistry, and land use. As a part of this analysis, we compare heterotrophic respiration models based solely on temperature and soil moisture controls (zero‐order models) with models that depend on available substrate as well (first‐order models). As indicators of regional and global CO_2 exchange, we use maps of monthly global net ecosystem production, growing season net flux (GSNF), and simulated atmospheric CO_2 concentrations from an atmospheric tracer transport model. In one first‐order model, CASA, variations on the representation of the seasonal flow of organic matter from plants to heterotrophs can increase global GSNF as much as 60% (5.7 Pg C yr^(−1)) above estimates obtained from a zero‐order model. Under a new first‐order scheme that includes separate seasonal dynamics for leaf litterfall, fine root mortality, coarse woody debris, and herbivory, we observe an increase in GSNF of 8% (0.7 Pg C yr^(−1)) over that predicted by the zero‐order model. The increase in seasonality of CO2 exchange in first‐order models reflects the dynamics of labile litter fractions; specifically, the rapid decomposition of a pulse of labile leaf and fine root litter that enters the heterotrophic community primarily from the middle to the end of the growing season shifts respiration outside the growing season. From the perspective of a first‐order model, we then explore the consequences of land use change and winter temperature anomalies on the amplitude of the seasonal cycle of atmospheric CO_2. Agricultural practices that accelerate decomposition may drive a long‐term increase in the amplitude, independent of human impacts on plant production. Consideration of first‐order litter decomposition dynamics may also help explain year‐to‐year variation in the amplitude

Market inefficiency identified by both single and multiple currency trends

Many studies have shown that there are good reasons to claim very low predictability of currency nevertheless, the deviations from true randomness exist which have potential predictive and prognostic power [J.James, Quantitative finance 3 (2003) C75-C77]. We analyze the local trends which are of the main focus of the technical analysis. In this article we introduced various statistical quantities examining role of single temporal discretized trend or multitude of trends corresponding to different time delays. Our specific analysis based on Euro-dollar currency pair data at the one minute frequency suggests the importance of cumulative nonrandom effect of trends on the forecasting performance

The contribution of terrestrial sources and sinks to trends in the seasonal cycle of atmospheric carbon dioxide

We characterized decadal changes in the amplitude and shape of the seasonal cycle of atmospheric CO_2 with three kinds of analysis. First, we calculated the trends in the seasonal cycle of measured atmospheric CO_2 at observation stations in the National Oceanic and Atmospheric Administration Climate Monitoring and Diagnostic Laboratory network. Second, we assessed the impact of terrestrial ecosystems in various localities on the mean seasonal cycle of CO_2 at observation stations using the Carnegie‐Ames‐Stanford Approach terrestrial biosphere model and the Goddard Institute for Space Studies (GISS) atmospheric tracer transport model. Third, we used the GISS tracer model to quantify the contribution of terrestrial sources and sinks to trends in the seasonal cycle of atmospheric CO_2 for the period 1961–1990, specifically examining the effects of biomass burning, emissions from fossil fuel combustion, and regional increases in net primary production (NPP). Our analysis supports results from previous studies that indicate a significant positive increase in the amplitude of the seasonal cycle of CO_2 at Arctic and subarctic observation stations. For stations north of 55°N the amplitude increased at a mean rate of 0.66% yr^(−1) from 1981 to 1995. From the analysis of ecosystem impacts on the mean seasonal cycle we find that tundra, boreal forest, and other northern ecosystems are responsible for most of the seasonal variation in CO_2 at stations north of 55°N. The effects of tropical biomass burning on trends in the seasonal cycle are minimal at these stations, probably because of strong vertical convection in equatorial regions. From 1981 to 1990, fossil fuel emissions contributed a trend of 0.20% yr^(−1) to the seasonal cycle amplitude at Mauna Loa and less than 0.10% yr^(−1) at stations north of 55°N. To match the observed amplitude increases at Arctic and subarctic stations with NPP increases, we find that north of 30°N a 1.7 Pg C yr^(−1) terrestrial sink would be required. In contrast, over regions south of 30°N, even large NPP increases and accompanying terrestrial sinks would be insufficient to account for the increase in high‐latitude amplitudes

Substrate limitations for heterotrophs: Implications for models that estimate the seasonal cycle of atmospheric CO_2

We examine the sensitivity of the seasonal cycle of heterotrophic respiration to model estimates of litterfall seasonality, herbivory, plant allocation, tissue chemistry, and land use. As a part of this analysis, we compare heterotrophic respiration models based solely on temperature and soil moisture controls (zero‐order models) with models that depend on available substrate as well (first‐order models). As indicators of regional and global CO_2 exchange, we use maps of monthly global net ecosystem production, growing season net flux (GSNF), and simulated atmospheric CO_2 concentrations from an atmospheric tracer transport model. In one first‐order model, CASA, variations on the representation of the seasonal flow of organic matter from plants to heterotrophs can increase global GSNF as much as 60% (5.7 Pg C yr^(−1)) above estimates obtained from a zero‐order model. Under a new first‐order scheme that includes separate seasonal dynamics for leaf litterfall, fine root mortality, coarse woody debris, and herbivory, we observe an increase in GSNF of 8% (0.7 Pg C yr^(−1)) over that predicted by the zero‐order model. The increase in seasonality of CO2 exchange in first‐order models reflects the dynamics of labile litter fractions; specifically, the rapid decomposition of a pulse of labile leaf and fine root litter that enters the heterotrophic community primarily from the middle to the end of the growing season shifts respiration outside the growing season. From the perspective of a first‐order model, we then explore the consequences of land use change and winter temperature anomalies on the amplitude of the seasonal cycle of atmospheric CO_2. Agricultural practices that accelerate decomposition may drive a long‐term increase in the amplitude, independent of human impacts on plant production. Consideration of first‐order litter decomposition dynamics may also help explain year‐to‐year variation in the amplitude

Carbon-nitrogen interactions regulate climate-carbon cycle feedbacks : results from an atmosphere-ocean general circulation model

© 2009 The Authors. This article is distributed under the terms of the Creative Commons Attribution 3.0 License. The definitive version was published in Biogeosciences 6 (2009): 2099-2120, doi:10.5194/bg-6-2099-2009Inclusion of fundamental ecological interactions between carbon and nitrogen cycles in the land component of an atmosphere-ocean general circulation model (AOGCM) leads to decreased carbon uptake associated with CO2 fertilization, and increased carbon uptake associated with warming of the climate system. The balance of these two opposing effects is to reduce the fraction of anthropogenic CO2 predicted to be sequestered in land ecosystems. The primary mechanism responsible for increased land carbon storage under radiatively forced climate change is shown to be fertilization of plant growth by increased mineralization of nitrogen directly associated with increased decomposition of soil organic matter under a warming climate, which in this particular model results in a negative gain for the climate-carbon feedback. Estimates for the land and ocean sink fractions of recent anthropogenic emissions are individually within the range of observational estimates, but the combined land plus ocean sink fractions produce an airborne fraction which is too high compared to observations. This bias is likely due in part to an underestimation of the ocean sink fraction. Our results show a significant growth in the airborne fraction of anthropogenic CO2 emissions over the coming century, attributable in part to a steady decline in the ocean sink fraction. Comparison to experimental studies on the fate of radio-labeled nitrogen tracers in temperate forests indicates that the model representation of competition between plants and microbes for new mineral nitrogen resources is reasonable. Our results suggest a weaker dependence of net land carbon flux on soil moisture changes in tropical regions, and a stronger positive growth response to warming in those regions, than predicted by a similar AOGCM implemented without land carbon-nitrogen interactions. We expect that the between-model uncertainty in predictions of future atmospheric CO2 concentration and associated anthropogenic climate change will be reduced as additional climate models introduce carbon-nitrogen cycle interactions in their land components.This work was supported in part by NASA Earth Science Enterprise, Terrestrial Ecology Program, grant #W19,953 to P. E. Thornton. Support was provided by the National Center for Atmospheric Research (NCAR) through the NCAR Community Climate System Modeling program, and through the NCAR Biogeosciences program. Additional support was provided by the US Department of Energy, Office of Science, Office of Biological and Environmental Research. I. Fung, S. Doney, N. Mahowald, and J. Randerson acknowledge support from National Science Foundation, Atmospheric Sciences Division, through the Carbon and Water Initiative

A Large Population Histology Study Showing the Lack of Association between ALT Elevation and Significant Fibrosis in Chronic Hepatitis B

OBJECTIVE: We determined the association between various clinical parameters and significant liver injury in both hepatitis B e antigen (HBeAg)-positive and HBeAg-negative patients. METHODS: From 1994 to 2008, liver biopsy was performed on 319 treatment-naive CHB patients. Histologic assessment was based on the Knodell histologic activity index for necroinflammation and the Ishak fibrosis staging for fibrosis. RESULTS: 211 HBeAg-positive and 108 HBeAg-negative patients were recruited, with a median age of 31 and 46 years respectively. 9 out of 40 (22.5%) HBeAg-positive patients with normal ALT had significant histologic abnormalities (necroinflammation grading >/= 7 or fibrosis score >/= 3). There was a significant difference in fibrosis scores among HBeAg-positive patients with an ALT level within the Prati criteria (30 U/L for men, 19 U/L for women) and patients with a normal ALT but exceeding the Prati criteria (p = 0.024). Age, aspartate aminotransferase and platelet count were independent predictors of significant fibrosis in HBeAg-positive patients with an elevated ALT by multivariate analysis (p = 0.007, 0.047 and 0.045 respectively). HBV DNA and platelet count were predictors of significant fibrosis in HBeAg-negative disease (p = 0.020 and 0.015 respectively). An elevated ALT was not predictive of significant fibrosis for HBeAg-positive (p = 0.345) and -negative (p = 0.544) disease. There was no significant difference in fibrosis staging among ALT 1-2 x upper limit of normal (ULN) and > x 2 ULN for both HBeAg-positive (p = 0.098) and -negative (p = 0.838) disease. CONCLUSION: An elevated ALT does not accurately predict significant liver injury. Decisions on commencing antiviral therapy should not be heavily based on a particular ALT threshold.published_or_final_versio

The use of transient elastography in the management of chronic hepatitis B

There has been increasing interest in noninvasive methods of assessing liver fibrosis over the last decade. The use of transient elastography in measuring liver stiffness has become the forefront of a wide range of noninvasive tools. Most of the other methods are based on measurements of biomarkers associated with fibrosis. There are several reasons for its wide acceptance, including the ease of performing a scan, the short procedure time, the results being immediately available on completion of the examination, and its reproducibility. For chronic hepatitis B (CHB), the cut-off values for F3 and F4 fibrosis range between 7.5–12.0 and 11.0–13.4 kPa, respectively, although the cut-offs may be slightly lower in those with normal ALT. In addition to measuring liver fibrosis, recent studies have demonstrated several other roles for transient elastography, including selecting patients who will benefit from antiviral therapy, monitoring response to antiviral therapy, and predicting long-term outcomes. However, there are limitations associated with transient elastography, including the confounding effects of inflammatory activity, and to a lesser extent, steatosis, on liver stiffness. There is also reduced accuracy observed in lower fibrosis stages (F0–F2). Furthermore, the incidences of failed and unreliable scan have been reported to be ~ 3 and 16%, respectively. Although liver biopsy can be avoided in an estimated 50–60% using transient elastography, in situations where liver stiffness measurement is nondiagnostic or inconsistent with the clinical picture, a biopsy is still recommended. Further studies are needed to consolidate the role of transient elastography in the management of CHB, and for incorporation of this method into current treatment guidelines