An Exploration of Technology Leadership in Three Maine Public School Districts

The promise of technology for positively influencing student outcomes is being hampered by a lack of understanding of who is leading technology in public schools and differing beliefs of technology use among technology leaders. The purpose of this qualitative multi-case study was to describe and understand the nature of technology leadership in three Maine public school districts. Research questions explored the roles, responsibilities, values, and beliefs of the technology leaders and examined how technology leaders mobilized stakeholders in using technology to positively influence student outcomes. Fifteen participants were interviewed from across three case sites. Data analysis was guided by the conceptual frameworkusing a “bottom-up” inductive approach. From the results of the study, technology leadership is defined as the enactment of a shared vision for learning with technology that: incorporates the values and beliefs of the technology leaders, teachers, and staff; utilizes a leadership framework where all technology leaders can lead in an atmosphere of trust; and uses adaptive leadership strategies (Heifetz, 1994) to mobilize technology leaders, teachers, and staff in using technology for the enhancement of student learning

Toward Monodisperse Poly(γ-benzyl α,L-glutamate): Uniform, Polar, Molecular Rods

Poly(γ-benzyl α,L-glutamate) (PBLG) has been widely used in studies of the physics of rod-like polymer chains. The helical structure of PBLG gives rise to considerable chain stiffness, such that the persistence length of the chain is on the order of 70 nm in helicogenic solvents. This feature, coupled with the ease of synthesis and good solubility of the polymer has made PBLG the system of choice for the study of both isotropic and liquid crystalline solutions of rod-like macromolecules

Engineered Proteins in Materials Research

Peptides and proteins have attracted scientific and technological interest largely because of their intriguing properties as catalysts, receptors, signalling molecules, and therapeutic agents. In attempts to understand and exploit these properties, protein engineering has been used primarily to obtain precious proteins in increased quantities, or to explore systematic alterations in protein sequence through site-directed mutagenesis. Design of protein structures de novo ("from scratch") has attracted less attention, and has been directed in the main toward studies of protein folding (Kamtekar et al., 1993). Such studies represent a key element in the current vigorous investigation of the connections between amino acid sequence and the three-dimensional structures of isolated protein chains in aqueous solution. This chapter describes protein engineering of quite another sort, in which the proteinacious nature of the product is less important than its macromolecular character

Synthesis and Characterization of Periodic Polypeptides Containing Repeating —(AlaGly)_xGluGly— Sequences

We have expressed in E. coli a series of periodic polypeptides represented by sequence 1. Our objective has been an understanding of the role of chemical sequence in determining the chain folding behavior of periodic macromolecules. Molecular organization has been examined by infrared spectroscopy and ^1H and ^(13)C NMR methods and a preliminary model of the folded structure has been developed

Effective Area-Elasticity and Tension of Micro-manipulated Membranes

We evaluate the effective Hamiltonian governing, at the optically resolved scale, the elastic properties of micro-manipulated membranes. We identify floppy, entropic-tense and stretched-tense regimes, representing different behaviors of the effective area-elasticity of the membrane. The corresponding effective tension depends on the microscopic parameters (total area, bending rigidity) and on the optically visible area, which is controlled by the imposed external constraints. We successfully compare our predictions with recent data on micropipette experiments.Comment: To be published in Phys. Rev. Let

Incidence of transient congenital hypothyroidism due to maternal thyrotropin receptor-blocking antibodies in over one million babies

To determine the incidence of transient congenital hypothyroidism due to TSH receptor-blocking antibodies, we screened dried blood specimens obtained from 788 neonates identified as having possible congenital hypothyroidism (from a total population of 1,614,166 babies) and 121 controls. A RRA was used. The potency of blood spot TSH binding inhibitory activity was compared with the severity of congenital hypothyroidism to assess the possible etiological relationship. Maternal serum was studied to confirm the presence of blocking antibodies by both RRA and bioassay. Blood spots obtained from 9 infants contained potent TSH receptor-blocking activity. Samples from 2 additional babies, studied because of clinical suspicion of the disease, were also positive. Long term outcome was known in 8 of the 11 babies, and all had transient disease. Neonates with TSH receptor-blocking activity greater than 132 U/L had a significantly lower T4 level (P \u3c 0.05) and higher TSH (P \u3c 0.005) than those in whom TSH binding-inhibitory activity was less than 132 U/L. All 9 mothers had autoimmune thyroid disease, and 3 had more than 1 affected child. Potent blocking activity was present in 7 maternal serum samples as long as 7 yr after the births of their affected babies. We conclude that measurement of TSH binding-inhibitory activity in dried neonatal blood specimens is a simple and effective method to predict the occurrence of transient congenital hypothyroidism. The incidence of this disorder in North America is 1 in 180,000 normal infants, or approximately 2% of babies with congenital hypothyroidism

Comments on the Role of Molecular Genetics in Polymer Materials Science

The most fundamental goal of the synthetic chemist is control of molecular architecture. With respect to small molecules (i.e., those of molecular weight less than a few thousand), this means absolute control of chemical connectivity and stereochemistry – complete specification of molecular structure. But in macromolecular chemistry, controlled architecture has meant something quite different. Because polymerizations are in general statistical processes, conventional polymeric materials are characterized by substantial heterogeneity in chain length, sequence and stereochemistry. Control is exercised in a statistical sense only, and considerable skill is required to control even the average properties of the chain population and the dispersity in those properties

Mixed pairing symmetry in \kappa-(BEDT-TTF)_2 X organic superconductors from ultrasonic velocity measurements

Discontinuities in elastic constants are detected at the superconducting transition of layered organic conductors \kappa-(BEDT-TTF)_{2}X by longitudinal and transverse ultrasonic velocity measurements. Symmetry arguments show that discontinuities in shear elastic constants can be explained in the orthorhombic compound only if the superconducting order parameter has a mixed character that can be of two types, either A_{1g}+B_{1g} or B_{2g}+B_{3g} in the classification of irreducible representations of the orthorhombic point group D_{2h}. Consistency with other measurements suggests that the A_{1g}+B_{1g} (d_{xy}+d_{z(x+y)}) possibility is realized. Such clear symmetry-imposed signatures of mixed order parameters have not been observed in other superconducting compounds.Comment: 5 pages, LaTeX,3 figure

Microwave Electrodynamics of Electron-Doped Cuprate Superconductors

We report microwave cavity perturbation measurements of the temperature dependence of the penetration depth, lambda(T), and conductivity, sigma(T) of Pr_{2-x}Ce_{x}CuO_{4-delta} (PCCO) crystals, as well as parallel-plate resonator measurements of lambda(T) in PCCO thin films. Penetration depth measurements are also presented for a Nd_{2-x}Ce_{x}CuO_{4-delta} (NCCO) crystal. We find that delta-lambda(T) has a power-law behavior for T<T_c/3, and conclude that the electron-doped cuprate superconductors have nodes in the superconducting gap. Furthermore, using the surface impedance, we have derived the real part of the conductivity, sigma_1(T), below T_c and found a behavior similar to that observed in hole-doped cuprates.Comment: 4 pages, 4 figures, 1 table. Submitted to Physical Review Letters revised version: new figures, sample characteristics added to table, general clarification give