An experimental study of growth and phase change of polar stratospheric cloud particles

This report describes the progress made on understanding phase changes related to solutions which may comprise Polar Stratospheric Clouds. In particular, it is concerned with techniques for investigating specific classes of metastability and phase change which may be important not only in Polar Stratospheric Clouds but in all atmospheric aerosols in general. While the lower level atmospheric aerosol consists of mixtures of (NH4)(SO4)2, NH4HSO4, NaCl among others, there is evidence that aerosol at PSC levels is composed of acid aerosol, either injected from volcanic events (such as Pinatubo) or having diffused upward from the lower atmosphere. In particular, sulfuric acid and nitric acid are known to occur at PSC levels, and are suspected of catalyzing ozone destruction reactions by adsorption on surfaces of crystallized particles. The present study has centered on two approaches: (1) the extent of supercooling (with respect to ice) and supersaturation (with respect to hydrate) and the nature of crystal growth in acid solutions of specific molality; and (2) the nature of growth from the vapor of HNO3 - H2O crystals both on a substrate and on a pre-existing aerosol

Linking Forest Carbon Sequestration, CO2 Flux, and Climate: 20 Years of Eddy Covariance Data from the Howland Forest, Maine

Forest productivity is known to vary in response to annual fluctuations in climate. By assessing how closely forest productivity tracks climate on an annual basis, we can gauge climate sensitivity for a given location. However, our understanding of forest productivity is limited, in part, by the complex methods needed to measure annual stand-level productivity. The eddy covariance technique, whereby CO2 exchange (flux) is continuously measured at the canopy-atmosphere interface, has clarified our understanding of stand-level carbon dynamics by addressing productivity and its response to climate fluctuations. Biometric approaches, where forest productivity is estimated from the annual growth of individual trees, can offer a more economical alternative to continuous CO2 flux measurements, while providing annual estimates of CO2 assimilation. However, attempts to link these measurements of productivity (i.e., CO2 flux and tree growth) have produced inconsistent results and demonstrated a need for further research. Using long-term forest inventory data paired with tree-ring data from a mixed-species conifer forest at the Howland Research Forest, central Maine, we developed annual estimates of productivity at species- and stand-levels. We used annual carbon mass increment (derived from tree-ring data and species-specific wood densities) per unit area as a measure of productivity because it allows direct comparisons with CO2 flux data. Our results demonstrated strong correlations between carbon mass increment and annual CO2 flux measurements summarized from previous-year fall to current-year fall, an improvement from calendar year summaries. Further, our results suggest tree growth was lagged one year behind CO2 flux (i.e., assimilated CO2 was not allocated to growth until the following year) for about the first half of the time-series, but later became synchronized with current year assimilation. We suspect the shift to synchrony reflects the onset of above-average spring temperatures, which shifted carbon allocation from storage to current-year wood formation. We also explored the use of annual carbon mass increment as an alternative to traditional standardized tree-ring chronologies for assessing climate–growth relationships. Our approach allowed us to assess these relationships across three levels of organization: individual tree-, species-, and stand-levels. We believe this approach is preferable in complex mixed-species forests, as it provides insights unavailable from the traditional standardization approach, which is restricted to the species level. Our results demonstrated that stand-level growth was sensitive to a different set of climate variables than those affecting individual species. We documented previous summer precipitation (higher better) and spring temperature (warmer better) as the most influential variables affecting stand-level growth at Howland Forest. We conclude the use of carbon mass increment has a broad range of applications within studies of forest productivity, and we suggest that future studies using tree-ring data consider the potential benefits of converting to carbon-mass increment. The following thesis highlights the benefits of implementing annual carbon mass increments for the purpose of addressing a broad range of research questions

Greece: Infection

Greece is a country that has shaped the western world’s architecture, societies, and governments. They also seem to have some of the greatest internal issues of developed countries in the world with the recent refugee crisis stemming from the Middle East. Greece, a country which already experiences many financial issues, is left with a huge lack of resources and staff to accommodate even their own population. With the lack of health resources and nurses, many short-cuts have led to an unprecedented amount of infection related deaths from the country that created Western Civilization. This brief discusses the causes of these issues and the necessary assistance that world organizations should give, as well as problems that this crisis will cause for the people simply trying to receive medical aid within a hospital. Finally, it will explain some possible solutions that the country could implement in order to regain the trust of their health system and to control the financial and refugee problems that are suffocating the countries resources

Assessment of Data Collection Techniques and White-nose Syndrome Effects on Bat Communities of South Carolina

White-nose syndrome (WNS), an infectious disease that has caused massive declines in bat populations since its discovery in 2006, may be indirectly affecting bat community structure. As WNS-susceptible species populations decline, WNS-resistant species may be taking over foraging niches formerly occupied by WNS-susceptible species. We hypothesized that bat communities located in WNS-positive areas in South Carolina have experienced niche partitioning relaxation. First, because some pre-WNS acoustic data were collected using different methods than those primarily used today, we examined if sampling method affected detection probabilities and our interpretation of habitat use of bats. We collected data using passive and active techniques in July 2017 at the Savannah River Site in South Carolina. We used occupancy modeling to determine if data collection method influenced detection probability of bats. We found that method had a significant effect on detection probabilities of all species and that passively sampling throughout the night yielded the highest detection probability. To further examine if data collection method influenced habitat use conclusions, we used occupancy modeling to analyze data collected passively in July to August 2016 and July 2017 and compared our results to a historical study in which active acoustic sampling was used at the same sites in 2001. We found that some parameters had the same effect between studies for some species, while other parameters had a different effect between studies. We concluded that data collected using different methods was not comparable. Second, revisiting a WNS-positive site where passive acoustic sampling was conducted historically, we examined the extent to which spatial and temporal niche partitioning occurred pre- and post-WNS. Specifically, we collected data using acoustic detectors from May to August 2004 and 2005 (“pre-WNS”) and from May to August 2016 and May to June 2017 (“post-WNS”) in the Andrew Pickens District (APD) of the Sumter National Forest in northwestern South Carolina. To examine changes in the spatial niche partitioning of the bat community, we used multi-season occupancy modeling and examined colonization and extinction probabilities. To examine temporal niche partitioning, we examined bat activity throughout the night using temporal overlap analysis. We found that the WNS-resistant species had higher colonization rates than WNS-susceptible species and changed their nightly activity so that it was more evenly distributed throughout the night post-WNS. Myotis, a WNS-susceptible genus, stopped using areas in hardwood habitat and changed when they were active at night post-WNS. Tricolored bats, a WNS-susceptible species, exhibited changes in the areas they were using, though this did not seem to be contingent on the presence of other species, and did not change when they were active at night post-WNS. These results provide evidence that WNS destabilized the spatial and temporal niche partitioning exhibited by bats pre-WNS in South Carolina and further evidence that WNS is both directly and indirectly affecting the bat communities in North America

The Impact of Guided Reading Instruction on Elementary Students\u27 Reading Fluency and Accuracy

This study examined the impact of Guided Reading instruction on elementary students’ ability to read with fluency and accuracy. A one-way analysis of covariance with pre and posttest design was performed and applied to determine the impact of Guided Reading instruction on elementary students’ reading fluency and accuracy. The sample of subjects included 108 elementary students in the fourth and fifth grade. To examine the impact of Guided Reading instruction, students’ Developmental Reading Assessment (DRA2) pre and posttest scores to include words per minute and accuracy percentage were compared. The analyses revealed proportionate differences in students’ fluency and accuracy. As direct implementation of Guided Reading was applied to student instruction, a significant difference was noted in the words per minute students read. However, as direct implementation of Guided Reading instruction was applied to student instruction, a significant difference was not noted in the accuracy rate of words per minute read. This research of Guided Reading instruction affords educators a multi-modality instructional strategy to impact the reading formation and foundation of elementary students. Recommendations to compliment this study to further benefit reading instruction could include the application of Guided Reading as it relates to and impacts student reading comprehension

Elastomer Compound Developed for High Wear Applications

The U.S. Army is currently spending 300 million dollars per year replacing rubber track pads. An experimental rubber compound has been developed which exhibits 2 to 3 times greater service life than standard production pad compounds. To improve the service life of the tank track pads various aspects of rubber chemistry were explored including polymer, curing and reinforcing systems. Compounds that exhibited superior physical properties based on laboratory data were then fabricated into tank pads and field tested. This paper will discuss the compounding studies, laboratory data and field testing that led to the high wear elastomer compound

Support Program for Students with Autism in Postsecondary Education

The Focused Skill Training (FST) program at Kirkwood Community College is a support program for students with Autism Spectrum Disorder. This presentation will provide a brief overview of the FST program, strategies and tools to help students with Autism Spectrum Disorder be successful, and discuss our collaboration among campus and community resources. Time will be allocated to allow for open discussion and questions