NCR444

In cooperation with USDA and the NCR Educational Materials Project, USDA grant # 89-38500-4319.J.E. Morris, Pond culture of channel catfish in the north central region, Iowa State University, April 1993

Best Management Practices for Aquatic Vegetation Management in Lakes

Aquatic plants are an important component of well functioning lake ecosystems. Plant abundance is influenced by sediments, nutrients and water clarity. Given the dominance of agriculture in Iowa, nutrients and soil lost from “leaky” watersheds combine to create ideal habitat for growth of aquatic plants in lakes and ponds and hasten eutrophication. Under these conditions, plant growth can become a nuisance and reduce recreation, especially shoreline angling and boating. These nuisance growths present special problems to lake managers and those interested in lake-based recreation. Given the complexity of the aquatic vegetation often found in lakes, there is no one long-term solution to their management although grass carp and herbicides have been used with that goal. The best solution to a lake’s specific vegetation problem will be a combination of preventative, physical, biological and chemical options tuned to that specific lake’s environmental conditions and fishery needs. Development of a strategy to address the control of nuisance aquatic vegetation with the ultimate goal of producing a set of BMPs is needed to manage plants in Iowa’s ponds and lakes. This information will provide lake managers with the best methods and techniques to sample, assess, and manage nuisance aquatic vegetation. Plans developed from these strategies will link critical watershed characteristics, lake bathymetry, water quality, and density and diversity of aquatic plants to management options that benefit fish and fishing. Considerations will include the cost and benefit of various alternatives and the likelihood for success. This project was initiated July 2006 and continues through June 2009

Best Management Practices for Aquatic Vegetation Management in Lakes

Aquatic plants are an important component of well functioning lake ecosystems. Plant abundance is influenced by sediments, nutrients and water clarity. Given the dominance of agriculture in Iowa, nutrients and soil lost from “leaky” watersheds combine to create ideal habitat for growth of aquatic plants in lakes and ponds and hasten eutrophication. Under these conditions, plant growth can become a nuisance and reduce recreation, especially shoreline angling and boating. These nuisance growths present special problems to lake managers and those interested in lake-based recreation. Given the complexity of the aquatic vegetation often found in lakes, there is no one long-term solution to their management although grass carp and herbicides have been used with that goal. The best solution to a lake’s specific vegetation problem will be a combination of preventative, physical, biological and chemical options tuned to that specific lake’s environmental conditions and fishery needs. Development of a strategy to address the control of nuisance aquatic vegetation with the ultimate goal of producing a set of BMPs is needed to manage plants in Iowa’s ponds and lakes. This information will provide lake managers with the best methods and techniques to sample, assess, and manage nuisance aquatic vegetation. Plans developed from these strategies will link critical watershed characteristics, lake bathymetry, water quality, and density and diversity of aquatic plants to management options that benefit fish and fishing. Considerations will include the cost and benefit of various alternatives and the likelihood for success. This project was initiated July 2006 and continues through June 2009

“My voices are just part of me, they don’t own me”: a qualitative investigation of Acceptance and Commitment Therapy groups for people experiencing psychosis

Background: This study aimed to generate a grounded theory of change processes as experienced by people with psychosis who engaged in an Acceptance and Commitment Therapy (ACT) group program. A secondary aim was to identify how participants described changes in their relationship to distress following the groups. Methods: The study used a qualitative research methodology, grounded theory. This was used to explore emergent themes in the participants’ subjective experiences of group ACT delivered in community mental health services. The experience of the ACT group process was investigated for nine participants. Semi-structured interviews were used to explore how the group experience and the exercises, metaphors and skills promoted by ACT were used by participants in their daily lives. Results: There were four main themes emerging from the interviews: awareness, relating differently, reconnection with life, leaning on others. Conclusions: The participants all described experiencing subjective benefits from being involved in the ACT groups, along with perspectives on processes of change. These reports of changes were consistent with the model and extend our understanding of the lived experience of engaging in ACT for psychosis group

Dynamical Downscaling Projections of Late 21st Century U.S. Landfalling Hurricane Activity

U.S. landfalling tropical cyclone (TC) activity was projected for late 21st century conditions using a two-step dynamical downscaling framework. A regional atmospheric model, run for 27 seasons, generated tropical storm cases. Each storm case was re-simulated (up to 15 days) using the higher resolution GFDL hurricane model. Thirteen CMIP3 or CMIP5 modeled climate change projections were explored as scenarios. Robustness of projections was assessed using statistical significance tests and comparing the sign of changes derived from different models. The proportion of TCs (tropical storms and hurricanes) making U.S. landfall increases for the warming scenarios (by order 50% or more). For category 1-3 hurricane frequency, a robust decrease is projected (basin-wide), but robust changes are not projected for U.S. landfalling cases. A relatively robust increase in U.S. landfalling category 4-5 hurricane frequency is projected, averaging about +400% across the models; 10 of 13 models/ensembles project an increase (statistically significant in three individual models), while three models projected no change. The most robust projections overall for U.S. landfalling TC activity are for increased near-storm rainfall rates: these increases average +18% (all tropical storms and hurricanes), +26% (all hurricanes), and +37% (major hurricanes). Landfalling hurricane wind speed intensities show no robust signal, in contrast to a ~5% increase in basin-averaged TC intensity; basin-wide Power Dissipation Index (PDI) is projected to decrease, partly due to decreased duration. TC translation speed increases a few percent in most simulations. A caveat is the framework’s low correlation of modeled U.S. TC landfalls vs. observed interannual variations (1980-2016)

Impact of Upper-Tropospheric Temperature Anomalies and Vertical Wind Shear on Tropical Cyclone Evolution Using an Idealized Version of the Operational GFDL Hurricane Model

The GFDL hurricane modeling system, initiated in the 1970s, has progressed from a research tool to an operational system over four decades. This system is still in use today in research and operations, and its evolution will be briefly described. This study used an idealized version of the 2014 GFDL model to test its sensitivity across a wide range of three environmental factors that are often identified as key factors in tropical cyclone (TC) evolution: SST, atmospheric stability (upper-air thermal anomalies), and vertical wind shear (westerly through easterly). A wide range of minimum central pressure intensities resulted (905–980 hPa). The results confirm that a scenario (e.g., global warming) in which the upper troposphere warms relative to the surface will have less TC intensification than one with a uniform warming with height. The TC rainfall is also investigated for the SST–stability parameter space. Rainfall increases for combinations of SST increase and increasing stability similar to global warming scenarios, consistent with climate change TC downscaling studies with the GFDL model. The forecast system’s sensitivity to vertical shear was also investigated. The idealized model simulations showed weak disturbances dissipating under strong easterly and westerly shear of 10 m s−1. A small bias for greater intensity under easterly sheared versus westerly sheared environments was found at lower values of SST. The impact of vertical shear on intensity was different when a strong vortex was used in the simulations. In this case, none of the initial disturbances weakened, and most intensified to some extent

Circumstellar Structure around Evolved Stars in the Cygnus-X Star Formation Region

We present observations of newly discovered 24 micron circumstellar structures detected with the Multiband Imaging Photometer for Spitzer (MIPS) around three evolved stars in the Cygnus-X star forming region. One of the objects, BD+43 3710, has a bipolar nebula, possibly due to an outflow or a torus of material. A second, HBHA 4202-22, a Wolf-Rayet candidate, shows a circular shell of 24 micron emission suggestive of either a limb-brightened shell or disk seen face-on. No diffuse emission was detected around either of these two objects in the Spitzer 3.6-8 micron Infrared Array Camera (IRAC) bands. The third object is the luminous blue variable candidate G79.29+0.46. We resolved the previously known inner ring in all four IRAC bands. The 24 micron emission from the inner ring extends ~1.2 arcmin beyond the shorter wavelength emission, well beyond what can be attributed to the difference in resolutions between MIPS and IRAC. Additionally, we have discovered an outer ring of 24 micron emission, possibly due to an earlier episode of mass loss. For the two shell stars, we present the results of radiative transfer models, constraining the stellar and dust shell parameters. The shells are composed of amorphous carbon grains, plus polycyclic aromatic hydrocarbons in the case of G79.29+0.46. Both G79.29+0.46 and HBHA 4202-22 lie behind the main Cygnus-X cloud. Although G79.29+0.46 may simply be on the far side of the cloud, HBHA 4202-22 is unrelated to the Cygnus-X star formation region.Comment: Accepted by A