Comparisons of Plant Species Richness, Relative Abundance, and Diversity in Two Prairie Restorations and Two Remnant Prairie Preserves in Stearns County, Minnesota

Prairies once covered vast areas of the Midwestern United States. In Minnesota, less than one percent of the state\u27s original eighteen million acres of prairie remains. Restoration of prairie vegetation has become a popular means of augmenting preservation efforts and increasing the area of this rare native habitat. In this study I used species-area and rank abundance relationships to compare the species richness and diversity of restored prairies at St. John\u27s University and Sand Prairie to remnant prairie preserves at Roscoe and Sand Prairie (all in Stearns County, Minnesota). I visually estimated relative abundance at each site using randomly placed 0.25m2 quadrats within representative areas of a uniform vegetation type. I derived species-area relationships using a series of enclosing quadrats that increased in size. Roscoe prairie had higher species richness and greater diversity than any other remnant or restoration project; however, the slopes of the species-area relationship of the Roscoe and Sand Prairie remnants were similar. The Sand Prairie remnant had greater species richness than did the Sand Prairie and St. Johnís restoration projects at small (1 ñ 10 m2) scales, but the slopes of the species-area relationship for the two restoration projects were significantly greater than those of the remnants. The two restored prairies exhibited similar patterns of diversity and richness across most prairie types. These results suggest differences in the species-area relationships between remnant and restored prairies, and that simple inventories often used to track the success of restorations may be augmented by the inclusion of species-area relationships

Exodus HD

To express the dramaticism of the themes in my work, I have written the following document in a pseudo-satirical voice, expressing both my interest in science fiction and my own eagerness to accept the profoundness of the Internet’s connectivity in my life. The sensational nature of the writing is both prophetic and personal, conflating manticism with art making. Due to the interlacing of the web’s influence with our individual lives, we must pay tribute to its power and guidance through endorsements of search engines and online marketplaces that have built a new world of convenience. This world of convenience is based on the accessibility of information and commerce, where online

Relativistic Winds from Compact Gamma-Ray Sources: II. Pair Loading and Radiative Acceleration in Gamma-ray Bursts

We consider the effects of rapid pair creation by an intense pulse of gamma-rays propagating ahead of a relativistic shock. Side-scattered photons colliding with the main gamma-ray beam amplify the density of scattering charges. The acceleration rate of the pair-loaded medium is calculated, and its limiting bulk Lorentz factor related to the spectrum and compactness of the photon source. One obtains, as a result, a definite prediction for the relative inertia in baryons and pairs. The deceleration of a relativistic shock in the moving medium, and the resulting synchrotron emissivity, are compared with existing calculations for a static medium. The radiative efficiency is increased dramatically by pair loading. When the initial ambient density exceeds a critical value, the scattering depth traversed by the main gamma-ray pulse rises above unity, and the pulse is broadened. These considerations place significant constraints on burst progenitors: a pre-burst mass loss rate exceeding 10^{-5} M_\odot per year is difficult to reconcile with individual pulses narrower than 10 s, unless the radiative efficiency is low. An anisotropic gamma-ray flux (on an angular scale \Gamma^{-1} or larger) drives a large velocity shear that greatly increases the energy in the seed magnetic field forward of the propagating shock.Comment: 19 pp., LaTeX (aaspp4.sty), revised 12/23/99, Ap. J. in press; summary section added and several minor improvements in presentatio

Quantum Energy Inequalities along stationary worldlines

Quantum energy inequalities (QEIs) are lower bounds on the averaged energy density of a quantum field. They have been proved for various field theories in general curved spacetimes but the explicit lower bound is not easily calculated in closed form. In this paper we study QEIs for the massless minimally coupled scalar field in four-dimensional Minkowski spacetime along stationary worldlines - curves whose velocity evolves under a 1-parameter Lorentz subgroup -- and find closed expressions for the QEI bound, in terms of curvature invariants of the worldline. Our general results are illustrated by specific computations for the six protoypical stationary worldlines. When the averaging period is taken to infinity, the QEI bound is consistent with a constant energy density along the worldline. For inertial and uniformly linearly accelerated worldlines, this constant value is attained by the Minkowski and Rindler vacuums respectively. It is an open question as to whether the bounds for other stationary worldlines are attained by other states of interest.Comment: 27 pages, 1 figure. v2 29 pages, 1 figure - additional commentary and references added. Final version to appear in Class Q Gra

Activity Theory as Theoretical Framework for Analyzing and Designing Global K-12 Collaborations in Engineering: A Case Study of a Thai-U.S. Elementary Engineering Project

The American engineering pipeline requires future workers to possess a unique skill set, comprised of content knowledge and 21st century skills, to recruit highly skilled, globally competitive engineers. Generally, 21st century skills are defined as the ability to think critically, communicate, collaborate in teams, and creatively solve problems. These skills are pertinent in training future engineers provided engineering utilizes the application of scientific knowledge within an inherently collaborative modality (the engineering design process). One component of developing 21st century skills and engineering competencies is the need for students to broaden their global awareness. Hence, American K-12 teachers are actively seeking opportunities for their students to collaborate with their international peers in an engineering context. One emergent pedagogical strategy is engaging in global K-12 collaborations in engineering in which K-12 students collaborate with international counterparts (another K-12 classroom/s or engineering expert/s), using the engineering design process, to create collaborative engineering solutions (projects). Because of the social complexity of global K-12 collaborations in engineering, the efficacy of these endeavors varies. This paper proposes Activity theory (AT) as a theoretical framework to analyze global K-12 collaborations in engineering. The authors use AT, in the context of an elementary-level U.S./Thai global collaboration, to document the experience and describe the activity. Using student, teacher, and expert created documents from the collaboration, the efficacy of the activity (student learning outcomes) were evaluated and then applied to AT. The rules, division of labor and community were found as areas that presented challenges to achieving successful outcomes within the activity system. This paper provides classroom teachers a roadmap for designing more successful global collaborations for K-12 engineering and 21st century skill development

Epistemic landscapes, optimal search and the division of cognitive labor

This paper examines two questions about scientists’ search for knowledge. First, which search strategies generate discoveries effectively? Second, is it advantageous to diversify search strategies? We argue pace Weisberg and Muldoon (2009) that, on the first question, a search strategy that deliberately seeks novel research approaches need not be optimal. On the second question, we argue they have not shown epistemic reasons exist for the division of cognitive labor, identifying the errors that led to their conclusions. Furthermore, we generalize the epistemic landscape model, showing that one should be skeptical about the benefits of social learning in epistemically complex environments

Methyl 6-amino-6-oxohexanoate

The title compound, C7H13NO3, adopts an approximately planar conformation. The torsion angles in the aliphatic chain between the carbonyl group C atoms range from 172.97 (14) to 179.38 (14)° and the r.m.s. deviation of all non-H atoms is 0.059 Å. The crystal packing is dominated by two strong N—H⋯O hydrogen bonds involving the amide groups and forming R 2 2(8) rings and C(4) chains. Overall, a two-dimensional network parallel to (100) is formed. A weak inter­molecular C—H⋯O inter­action is also present

STUDENT PERCEPTION OF PREPAREDNESS IN THE MIDST OF COVID-19: A SNAPSHOT FROM FIRST YEAR CHEMISTRY STUDENTS

The transition from high school to tertiary education can present many challenges for students. First year students must navigate new formal curricular, societal norms, physical environments, and support networks. An important factor for a successful transition from secondary to tertiary education is student preparedness. This transition period was thrown on its head due to the global challenges that the COVID-19 pandemic presented in 2020. The aim of this research was to identify and examine the perceptions of preparedness of first-year chemistry students, and if these perceptions were significantly impacted by COVID-19. Surveys were deployed to a first-year chemistry cohort at both the start and the end of semester, and follow up focus groups conducted after the conclusion of the semester. Results indicate that students’ perceptions of preparedness for studying chemistry increased over the course of the semester, however for studying at university in general the perception of preparedness decreased. The absence of in-person laboratory practicals was found to be a great concern for students, along with factors previously found to impact students’ perceptions. Reflections and findings of the students’ experiences will be presented from the first semester of 2020 delivered online through emergency remote teaching and learning