Management of invasive Allee species

In this study, we use a discrete, two-patch population model of an Allee species to examine different methods in managing invasions. We first analytically examine the model to show the presence of the strong Allee effect, and then we numerically explore the model to test the effectiveness of different management strategies. As expected invasion is facilitated by lower Allee thresholds, greater carrying capacities and greater proportions of dispersers. These effects are interacting, however, and moderated by population growth rate. Using the gypsy moth as an example species, we demonstrate that the effectiveness of different invasion management strategies is context-dependent, combining complementary methods may be preferable, and the preferred strategy may differ geographically. Specifically, we find methods for restricting movement to be more effective in areas of contiguous habitat and high Allee thresholds, where methods involving mating disruptions and raising Allee thresholds are more effective in areas of high habitat fragmentation

End of the War on Terror

Pages 89-9

Poem Ending on a Line by W.C.W. From a Letter to Byron Vazakas

Pages 87-8

Mating Flights of \u3ci\u3eEphoron Album\u3c/i\u3e (Ephemeroptera: Polymitarcidae) in Michigan

Mating flights of the mayfly Ephoron album (Say) were observed on the Sturgeon River in Houghton County, Michigan, on five evenings between 16 and 22 August, 1977. Peak emergence occurred about 30 minutes befqre sunset on 19 August and the flight period lasted about two hours. Many more adult males than females were collected on three evenings, but on one evening females greatly outnumbered males collected

High school choral students\u27 perceptions of their use of technology in their independent choral practice habits

This action research was based on an empirical, descriptive design using survey technique. The aim of this investigation was to determine the perceptions of high school choral students taught by the researcher in the Inland Northwest of the USA on their use of technology in their independent choral practice habits. All 45 choral students who provided signed consent forms were given a survey with open- ended questions. Data were analyzed using emergent thematic categories. The researcher asked students to reflect on background questions regarding the general nature of their practicing and, more specifically, on the role technology plays in their practicing. The results of the analysis determined that the use of technology (specifically the playback of recordings) is helpful in independent choral practice. Most students reported practicing 1 to 3 times a week (34.8%) for 10 to 30 minutes (61.9%) at a time. Many students identified practice venues (21.8%), time constraints (12.7%) and a lack of ability to play a keyboard instrument (14.5%) as being challenging factors to independent rehearsal. Through the use of individual vocal part recordings and full choir performance recordings, students reported being able to practice their parts with clear models of performance expectations (44.2%). Most students referred to the ease of practicing with the part recordings and their role in helping them practice (88.6%). The recordings were mostly played back on their cell phones (77.8%) or personal computers (44.4%). Overall, students reported positive attitudes towards having access to the technology and to using it on a regular basis. The results of this action research have been valuable in informing the researcher’s further decisions regarding the use of vocal part recordings and full choir performance recordings. The researcher was also able to use the background practicing information to help guide parents and guardians in supporting individual student practice environments, such as ensuring quiet, private spaces to rehearse. The researcher also looked at ways in which the school may provide practice venues for those unable to do so in the home

The analysis of aqueous mixtures using liquid chromatography: electrospray mass spectrometry

The focus of this dissertation is the use of chromatographic methods coupled with electrospray mass spectrometry (ES-MS) for the determination of both organic and inorganic compounds in aqueous solutions;The combination of liquid chromatography (LC) methods and ES-MS offers one of the foremost methods for determining compounds in complex aqueous solutions. In this work, LC-ES-MS methods are devised using ion exclusion chromatography, reversed phase chromatography, and ion exchange chromatography, as well as capillary electrophoresis (CE). For an aqueous sample, these LC-ES-MS and CE-ES-MS techniques require no sample preparation or analyte derivitization, which makes it possible to observe a wide variety of analytes as they exist in solution. The majority of this work focuses on the use of LC-ES-MS for the determination of unknown products and intermediates formed during electrochemical incineration (ECI), an experimental waste remediation process;Ion exclusion chromatography (IEC) was used to study small carboxylic acids. The effect of pH, solvent composition, sheath gas make-up, and presence of concentrated matrix was observed. Detection limits were found to range from 40 to 200 ppb for the direct infusion of most carboxylic acids and from 2 to 8 ppm for IEC-ES-MS;The ECI of benzoquinone is studied using IEC-ES-MS. Unknown intermediates and products are identified and observed as a function of ECI time. The ECI procedure is described in detail and electrode efficiency is evaluated. Mechanisms are also proposed for the production of maleic, succinic, malonic, and acetic acids;The ECI of 4-chlorophenol is observed using reversed phase liquid chromatography--ES-MS to study aromatic compounds, and ion exchange chromatography--ES-MS for organic and inorganic ions. The majority of this work is accomplished with ion exchange chromatography--ES-MS, which requires a suppressor to remove sodium ions from the mobile phase. The system has proven effective in the identification of a wide range of unknown compounds in complex aqueous solutions. Detection limits range from 50 ppb to 4 ppm;Capillary electrophoresis was also studied as a possible separation method coupled to an ES-MS. Different mobile phases are examined and tested with CE-ES-MS for the determination of carboxylic acids. Detection limits range between 1 and 10 ppm