Assessing the Impact of Bridging Analogies in Mechanics

The effects of bridging analogies teaching strategy and gender on Turkish high school students' misconceptions in mechanics were investigated. After a pilot study with 67 students in a nearby high school, the researchers administered the revised Mechanics Misconception Test to 119 high school students as a pretest. Students in the experimental group were instructed by using bridging analogies teaching strategy. At the end of a 3‐week treatment period, the same test was administered to all students as a posttest. The data were analyzed by using analysis of covariance (ANCOVA). The statistical results showed that bridging analogies teaching strategy was an effective means of reducing the number of misconceptions students held about normal forces, frictional forces, tension, gravity, inertia, and Newton's third law.     

Principal Congruence Subgroups of Hecke Groups H（√q）

Using the notion of quadratic reciprocity, we discuss the principal congruence subgroups of the Hecke groups H（√q）,q 〉 5 prime number.     

A family of p-adic twisted interpolation functions associated with the modified Bernoulli numbers

The main purpose of this paper is to construct a family of modified p-adic twisted functions, which interpolate the modified twisted q-Bernoulli polynomials and the generalized twisted q-Bernoulli numbers at negative integers. We also give some applications and examples related to these functions and numbers.     

Collective firing regularity of a scale-free Hodgkin–Huxley neuronal network in response to a subthreshold signal

We consider a scale-free network of stochastic HH neurons driven by a subthreshold periodic stimulus and investigate how the collective spiking regularity or the collective temporal coherence changes with the stimulus frequency, the intrinsic noise (or the cell size), the network average degree and the coupling strength. We show that the best temporal coherence is obtained for a certain level of the intrinsic noise when the frequencies of the external stimulus and the subthreshold oscillations of the network elements match. We also find that the collective regularity exhibits a resonance-like behavior depending on both the coupling strength and the network average degree at the optimal values of the stimulus frequency and the cell size, indicating that the best temporal coherence also requires an optimal coupling strength and an optimal average degree of the connectivity.     

Measurement of temperature, density, and particle transport with localized dopants in wire-array Z pinches

Axially localized NaF dopants are coated onto Al cylindrical wire arrays in order to act as spectroscopic tracers in the stagnated z-pinch plasma. Non-local-thermodynamic-equilibrium kinetic models fit to Na K-shell lines provide an independent measurement of the density and temperature that is consistent with spectroscopic analysis of K-shell emissions from Al and an alloyed Mg dopant. Axial transport of the Na dopant is observed, enabling quantitative study of instabilities in dense z-pinch plasmas.     

Synthesis,characterization and H<Subscript>2</Subscript> adsorption performances of polymeric Co(II) and Ni(II) complexes of pyrazine-2,3-dicarboxylic acid and 1-vinylimidazole

We studied the synthesis and characterization of polymeric coordination complexes of Co(II) and Ni(II) ions with pyrazine-2,3-dicarboxylic acid and 1-vinylimidazole. The e lemental analysis, infrared spectroscopy, powder X-ray diffraction, magnetic susceptibility, thermal analysis and X-ray single crystal techniques were used in the characterization. The X-ray single crystal analysis suggests that the pyrazine-2,3-dicarboxylato ligand acts as a bridging ligand through the oxygen atoms of the carboxylate groups and the nitrogen atoms on the pyrazine ring. The 1-vinylimidazole ligand behaves as a monodentate ligand via the ring nitrogen atom. Further, the H₂ adsorption studies were carried out at 75 K for various increasing pressures and the highest H₂ adsorption performances for Co(II) and Ni(II) complexes were estimated as 2.66 and 2.99 wt% at 87 bar. The theoretical calculations using the crystal data were also performed to determine the voids in the structure of Co(II) complex.     

Development of an improved method for trace analysis of chloramphenicol using molecularly imprinted polymers

A confirmatory method is described for the determination of the illegal antibiotic chloramphenicol using a specifically developed molecularly imprinted polymer (MIP) as the sample clean-up technique. The newly developed MIP was produced using an analogue to chloramphenicol as the template molecule. Using an analogue of the analyte as the template avoids a major traditional drawback associated with MIPs of residual template leeching or bleeding. The MIP described was used as a solid-phase extraction phase for the extraction of chloramphenicol from various sample matrices including honey, urine, milk and plasma. A full analytical method with quantification by LC-MS/MS is described. The method was fully validated according to the European Union (EU) criteria for the analysis of veterinary drug residues.     

Salicylaldehyde thiazolyl hydrazones as ligands

Novel bidentate Schiff base ligands, 2‐(2‐hydroxy‐5‐chloro/nitro)benzaldehyde‐[4‐(3‐methyl‐3‐mesitylcyclobutyl)‐1,3‐thiazol‐2‐yl]hydrazone, and their metal complexes have been prepared and characterized by elemental analyses, IR, ¹³C and ¹H NMR spectra, and magnetic susceptibility measurements. All the complexes were found to be mononuclear. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:617–621, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10201