Galactic Winds

Galactic winds are the primary mechanism by which energy and metals are recycled in galaxies and are deposited into the intergalactic medium. New observations are revealing the ubiquity of this process, particularly at high redshift. We describe the physics behind these winds, discuss the observational evidence for them in nearby star-forming and active galaxies and in the high-redshift universe, and consider the implications of energetic winds for the formation and evolution of galaxies and the intergalactic medium. To inspire future research, we conclude with a set of observational and theoretical challenges.Comment: Paper to be published in 2005 Annual Review of Astronomy & Astrophysics; revision based on comments from readers and production editor. Figure 1 was replaced to show the proper density scale. A PDF file combining both text and figures is available at http://www.astro.umd.edu/~veilleux/pubs/araa.pd

Extraction of tidal channel networks from airborne scanning laser altimetry and aerial photography

The study of the morphodynamics of tidal channel networks is important because of their role in tidal propagation and the evolution of salt-marshes and tidal flats. Channel dimensions range from tens of metres wide and metres deep near the low water mark to only 20-30cm wide and 20cm deep for the smallest channels on the marshes. The conventional method of measuring the networks is cumbersome, involving manual digitising of aerial photographs. This paper describes a semi-automatic knowledge-based network extraction method that is being implemented to work using airborne scanning laser altimetry (and later aerial photography). The channels exhibit a width variation of several orders of magnitude, making an approach based on multi-scale line detection difficult. The processing therefore uses multi-scale edge detection to detect channel edges, then associates adjacent anti-parallel edges together to form channels using a distance-with-destination transform. Breaks in the networks are repaired by extending channel ends in the direction of their ends to join with nearby channels, using domain knowledge that flow paths should proceed downhill and that any network fragment should be joined to a nearby fragment so as to connect eventually to the open sea

Alien Registration- Laslie, Cecil J. (Robbinston, Washington County)

https://digitalmaine.com/alien_docs/1412/thumbnail.jp

The Bryophytes of Knox County, Illinois

Field and herbarium studies conducted over an eleven month period found 84 taxa of bryophytes in Knox County. Included in this list are one hornwort (Class Anthocerotae), 15 liverworts (Class Hepaticae), and 68 mosses (Class Musci). Eighty-two species are new county records. Six previously unreported taxa produced during herbarium studies and one previous report were not relocated in the field. An annotated list provides collection data, location of voucher, and frequency of those species located in Knox County. A presettlement vegetation map is included to illustrate the location of collection sites

Image Analysis of Charged Bimodal Colloidal Systems in Microgravity.

Colloids are suspensions of two or more phases and have been topics of research for advanced, tunable materials for decades. Stabilization of colloids is typically attributed to thermodynamic mechanisms; however, recent studies have identified transport or entropic mechanisms that can potentially stabilize a thermodynamically unstable colloidal system. In this study, suspensions of silsesquioxane microparticles and zirconia nanoparticles were dispersed in a nitric acid solution and allowed to aggregate for 8-12 days in microgravity aboard the International Space Station. The suspensions were subsequently imaged periodically at 2.5x magnification. Due to the inadequacy of existing image analysis programs, the python package “Colloidspy” was developed to process these images and extract cluster boundaries. Trends of cluster area over time revealed two distinct behaviors. Some samples showed very low cluster growth rates and high cluster areas compared to microparticle size, while others showed an initial rapid growth phase, slowing to the low cluster growth rates of the other samples. The presence of this characteristic nonlinear phase coupled with the striking similarity in final growth rates of all samples suggests that the undocumented time between sample mixing and start of imaging may have been large enough that there was nonlinear growth in all samples, but only the final slow growth phase was captured in many of the samples. This type of behavior is not consistent with the linear agglomeration predictions of existing theory based on thermodynamic stabilization, but could be explained by the lack of buoyancy forces in microgravity allowing the space between clusters to increase as small clusters are incorporated into larger agglomerations. Further agglomeration could have been dominated by transport limitations even through the solution is still thermodynamically unstable. Further study into the role of transport mechanisms in dilute colloidal systems in microgravity should be conducted to shed further light on this unusual behavior

What Rocks the Vote? Citizens\u27 Views of Community Leaders and Political Engagement

Political engagement has an established body of research. However, one key area that has not been investigated in the field is the relationship between political engagement and type of community lived in. This study explores this relationship between type of community, past political engagement, perceptions of community leaders, attitude about political engagement, and socieodemographic characteristics. A conceptual model was developed based on existing literature. Utilizing a statewide survey conducted in 2009 that yielded 1,154 respondents with a response rate of 30.2% was used to explore these relationships. Using statistical procedures that test correlation were utilized to investigate the relationship between the key study variables. In addition, a regression model was created to be able to predict an individual’s political engagement. The result concluded that type of community does not significantly play a role in determining an individual’s political engagement. However other insights were revealed that showcase the complexity of political engagement and raise other questions about the role an individual’s attitude towards political engagement, and perception of community leaders affects their political engagement