Sexual Differentiation of the Rat Hypothalamus: An Evaluation of Sexual Behavior and Hypothalamic Morphology following Neonatal Manipulation

A thesis presented to the faculty of the School of Sciences and Mathematics at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science in Biology by Michael C. Stamper on August 24, 1984

A STUDY OF TEACHER AND PRINCIPAL PERCEPTIONS OF PROFESSIONAL LEARNING COMMUNITIES

Throughout the post-modern or post-professional age (2000-present), high stakes testing and accountability of public schools forced educational organizations to improve their professional practices to work collaboratively (Little, 2003). As a result, professional learning communities (PLCs) have been found to improve student learning among educational organizations (DuFour, 2007; Hord, 2004). During the past 20 years, a significant amount of research has been conducted, which describes PLCs in the educational settings (Vescio, Ross, & Adams, 2008) Researchers note a lack of empirical research which focuses on teacher and principal perceptions of PLCs (Hord & Sommers, 2008). The central focus of this study is to better understand teacher and principal perceptions of the five dimensions of professional learning communities (PLCs) as identified by Hord through reporting data collected using the Professional Learning Community Assessment- Revised (PLCA-R). This study seeks to report teacher and principal perceptions of PLCs to identify specific practices that are most common in Kentucky schools. Findings suggest teacher and principal perceptions differ regarding the five dimensions of PLCs as described by Hord. Findings also suggest that both teachers and principals agree that all five dimensions exist including: Shared and Supportive Leadership, Shared Values and Vision, Collective Learning and Application, Shared Personal Practice, Supportive Conditions – Relationships, and Supportive Conditions- Structures. However, principal perceptions reflect that PLC practices were more common than teachers reported

Global variation in the long-term seasonal changes observed in ionospheric F-region data

Long-term variability has previously been observed in the relative magnitude of annual and semi-annual variations in the critical frequency (related to the peak electron concentration) of the ionospheric F2 layer (foF2). In this paper we investigate the global patterns in such variability by calculating the time varying power ratio of semi-annual to annual components seen in ionospheric foF2 data sequences from 77 ionospheric monitoring stations around the world. The temporal variation in power ratios observed at each station was then correlated with the same parameter calculated from similar epochs for the Slough/Chilton dataset (for which there exists the longest continuous sequence of ionospheric data). This technique reveals strong regional variation in the data which bear a striking similarity to the regional variation observed in long-term changes to the height of the ionospheric F2 layer. We argue that since both the height and peak density of the ionospheric F2 region are influenced by changes to thermospheric circulation and composition, that the observed long-term and regional variability can be explained by such changes. In the absence of long-term measurements of thermospheric composition, detailed modelling work is required to investigate these processes

Building a Socio-technical Perspective of Community Resilience with a Semiotic Approach

Situated in the diversity and adversity of real-life contexts facing crisis situations, this research aims at boosting the resilience process within communities supported by digital and social technology. In this paper, eight community leaders in different parts of the world are invited to express their issues and wishes regarding the support of technology to face social challenges. Methods and artefacts based on the Organisational Semiotics (OS) and the Socially-Aware computing have been applied to analyse and consolidate this data. By providing both a systemic view of the problem and also leading to the identification of requirements, the analysis evidences some benefits of the OS-based approach to consolidate perspectives from different real-life scenarios towards building a socio-technical solution

Spontaneously modulated spin textures in a dipolar spinor Bose-Einstein condensate

Helical spin textures in a $^{87}$Rb F=1 spinor Bose-Einstein condensate are found to decay spontaneously toward a spatially modulated structure of spin domains. This evolution is ascribed to magnetic dipolar interactions that energetically favor the short-wavelength domains over the long-wavelength spin helix. This is confirmed by eliminating the dipolar interactions by a sequence of rf pulses and observing a suppression of the formation of the short-range domains. This study confirms the significance of magnetic dipole interactions in degenerate $^{87}$Rb F=1 spinor gases

Mean field ground state of a spin-1 condensate in a magnetic field

We revisit the topic of the mean field ground state of a spin-1 atomic condensate inside a uniform magnetic field ($B$) under the constraints that both the total number of atoms ($N$) and the magnetization ($\cal M$) are conserved. In the presence of an internal state (spin component) independent trap, we also investigate the dependence of the so-called single spatial mode approximation (SMA) on the magnitude of the magnetic field and ${\cal M}$. Our result indicate that the quadratic Zeeman effect is an important factor in balancing the mean field energy from elastic atom-atom collisions that are known to conserve both $N$ and $\cal M$.Comment: 13 pages, 9 figures, to be published in New J. Phys. (http://www.njp.org/

Evolution of a spinor condensate: coherent dynamics, dephasing and revivals

We present measurements and a theoretical model for the interplay of spin dependent interactions and external magnetic fields in atomic spinor condensates. We highlight general features like quadratic Zeeman dephasing and its influence on coherent spin mixing processes by focusing on a specific coherent superposition state in a F=1 $^{87}$Rb Bose-Einstein condensate. In particular, we observe the transition from coherent spinor oscillations to thermal equilibration

X-ray Crystallographic Characterization of the Co(II)-substituted Tris-bound Form of the Aminopeptidase from \u3cem\u3eAeromonas proteolytica\u3c/em\u3e

The X-ray crystal structure of the Co(II)-loaded form of the aminopeptidase from Aeromonas proteolytica ([CoCo(AAP)]) was solved to 2.2 Å resolution. [CoCo(AAP)] folds into an α/β globular domain with a twisted β-sheet hydrophobic core sandwiched between α-helices, identical to [ZnZn(AAP)]. Co(II) binding to AAP does not introduce any major conformational changes to the overall protein structure and the amino acid residues ligated to the dicobalt(II) cluster in [CoCo(AAP)] are the same as those in the native Zn(II)-loaded structure with only minor perturbations in bond lengths. The Co(II)–Co(II) distance is 3.3 Å. Tris(hydroxymethyl)aminomethane (Tris) coordinates to the dinuclear Co(II) active site of AAP with one of the Tris hydroxyl oxygen atoms (O4) forming a single oxygen atom bridge between the two Co(II) ions. This is the only Tris atom coordinated to the metals with Co1–O and Co2–O bonds distances of 2.2 and 1.9 Å, respectively. Each of the Co(II) ions resides in a distorted trigonal bipyramidal geometry. This important structure bridges the gap between previous structural and spectroscopic studies performed on AAP and is discussed in this context