Challenging Pre-Service Students\u27 Teaching Perspectives in an Inquiry-Focused Program

Inquiry teaching based on constructivist learning theory has been an emphasis in pre-service education for over a decade. In general, a developmental teaching perspective supports inquiry-based instruction where teachers view learners as constructors of knowledge and teaching as providing questions, problems, and challenges that form a bridge from the learners\u27 prior knowledge to a new, more sophisticated form of reasoning. Since teaching perspectives influence student learning, teacher effectiveness, and teacher attrition, challenging pre-service teachers to overcome experience-based convictions of a transmission perspective is necessary in teacher education. In this study, we examined the teaching perspectives of secondary, pre-service methods students at the midpoint of an inquiry-focused program. Our findings suggest that, despite being introduced to a variety of teaching perspectives, overcoming preconceptions of good teaching and considering a perspective counter to one\u27s disciplinary major presents a dilemma for pre-service teachers

Results of the 1997 Illinois Deer Hunter Survey

Administrative ReportReport issued on: July 17, 200

Coulomb Blockade Regime of a Single-Wall Nanotube

A model of carbon nanotube at half filling is studied. The Coulomb interaction is assumed to be unscreened. It is shown that this allows to develop the adiabatic approximation which leads to considerable simplifications in calculations of the excitation spectrum. We give a detailed analysis of the spectrum and the phase diagram at half filling and discuss effects of small doping. At small doping several phases develop strong superconducting fluctuations corresponding to various types of pairing

One-dimensional spin-liquid without magnon excitations

It is shown that a sufficiently strong four-spin interaction in the spin-1/2 spin ladder can cause dimerization. Such interaction can be generated either by phonons or (in the doped state) by the conventional Coulomb repulsion between the holes. The dimerized phases are thermodynamically undistinguishable from the Haldane phase, but have dramatically different correlation functions: the dynamical magnetic susceptibility, instead of displaying a sharp single magnon peak near $q = \pi$, shows only a two-particle threshold separated from the ground state by a gap.Comment: 9 pages, LaTex, to be published in Phys. Rev. Lett., vol. 78, May 199

The Evolution of Gas Clouds Falling in the Magnetized Galactic Halo: High Velocity Clouds (HVCs) Originated in the Galactic Fountain

In the Galactic fountain scenario, supernovae and/or stellar winds propel material into the Galactic halo. As the material cools, it condenses into clouds. By using FLASH three-dimensional magnetohydrodynamic simulations, we model and study the dynamical evolution of these gas clouds after they form and begin to fall toward the Galactic plane. In our simulations, we assume that the gas clouds form at a height of z=5 kpc above the Galactic midplane, then begin to fall from rest. We investigate how the cloud's evolution, dynamics, and interaction with the interstellar medium (ISM) are affected by the initial mass of the cloud. We find that clouds with sufficiently large initial densities (> 0.1 hydrogen atoms per cc) accelerate sufficiently and maintain sufficiently large column densities as to be observed and identified as high-velocity clouds (HVCs) even if the ISM is weakly magnetized (1.3 micro Gauss). We also investigate the effects of various possible magnetic field configurations. As expected, the ISM's resistance is greatest when the magnetic field is strong and perpendicular to the motion of the cloud. The trajectory of the cloud is guided by the magnetic field lines in cases where the magnetic field is oriented diagonal to the Galactic plane. The model cloud simulations show that the interactions between the cloud and the ISM can be understood via analogy to the shock tube problem which involves shock and rarefaction waves. We also discuss accelerated ambient gas, streamers of material ablated from the clouds, and the cloud's evolution from a sphere-shaped to a disk- or cigar-shaped object.Comment: 46 pages, 16 figures, 3 tables. Accepted for publication in Ap

Sensitive PCR Method for Detection of Escherichia coli 0157:H7 and Other Shiga toxin-producing Bacteria in Ground Meat

Sensitivity of a polymerase chain reaction (PCR) procedure was evaluated for Escherichia coli O157:H7 and Shiga toxin gene (stx) detection in ground beef and ground pork at contamination levels of 0.14, 1.4, and 14 colony forming units per gram (CFU/g) of meat. The PCR procedure, developed during our previous research, amplifies three target genes simultaneously: uidA that is specific for E. coli O157:H7, and stx1 and stx2, the genes for Shiga toxins 1 and 2, respectively. Detection of the uidA gene by the PCR was 91% sensitive in beef and 55% sensitive in pork, and 90% and 71% sensitive for stx gene detection in beef and pork, respectively. In comparison, detection of E. coli O157:H7 by culture, done simultaneously with PCR, was 53% sensitive in beef and 11% sensitive in pork. Results indicate that this PCR procedure is a rapid and sensitive method for STEC and E. coli O157:H7 detection in meat at contamination levels less than 1 CFU/g

Triplex PCR for Rapid Detection of Escherichia coli O157:H7 Directly from Ground Pork

A polymerase chain reaction (PCR) procedure is being developed to detect Escherichia coli O157:H7 and associated Shiga-like toxins (STX1 and STX2) directly from pork, bypassing the time-consuming microbial culture steps for identification. A triplex PCR procedure was adapted and conditions experimentally determined to efficiently amplify three target genes: uidA with unique sequence in E. coli O157:H7, and stx1 and stx2. A meat sample preparation technique developed in previous research was modified to allow detection of 0.2-2.0 colony forming units per gram (CFU./g.) of meat. Time required to complete the procedure after overnight incubation of samples is seven hours

System for the measurement of ultra-low stray light levels

An apparatus is described for measuring the effectiveness of stray light suppression light shields and baffle arrangements used in optical space experiments and large space telescopes. The light shield and baffle arrangement and a telescope model are contained in a vacuum chamber. A source of short, high-powered light energy illuminates portions of the light shield and baffle arrangement and reflects a portion of same to a photomultiplier tube by virtue of multipath scattering. The resulting signal is transferred to time-channel electronics timed by the firing of the high energy light source allowing time discrimination of the signal thereby enabling the light scattered and suppressed by the model to be distinguished from the walls and holders around the apparatus

An Inversion Disrupting FAM134B Is Associated with Sensory Neuropathy in the Border Collie Dog Breed

Sensory neuropathy in the Border Collie is a severe neurological disorder caused by the degeneration of sensory and, to a lesser extent, motor nerve cells with clinical signs starting between 2 and 7 months of age. Using a genome-wide association study approach with three cases and 170 breed matched controls, a suggestive locus for sensory neuropathy was identified that was followed up using a genome sequencing approach. An inversion disrupting the candidate gene FAM134B was identified. Genotyping of additional cases and controls and RNAseq analysis provided strong evidence that the inversion is causal. Evidence of cryptic splicing resulting in novel exon transcription for FAM134B was identified by RNAseq experiments. This investigation demonstrates the identification of a novel sensory neuropathy associated mutation, by mapping using a minimal set of cases and subsequent genome sequencing. Through mutation screening, it should be possible to reduce the frequency of or completely eliminate this debilitating condition from the Border Collie breed population