Investigating the impact of an urban community school effort on middle school STEM-related student outcomes over time through propensity score matched methods

This study investigates the impact of an urban community school reform initiative that focuses on an immigrant and refugee population in middle school. A 6th–8th grade cohort of students in the community school are followed over time and compared to a propensity score matched group on overall GPA, mathematics, and science academic outcomes and traditional college preparedness indicators. Further, a deeper dive into the intersection of gender and race/ethnicity was examined on all outcomes. Findings revealed that students in the urban community school demonstrated significantly more preparedness to enroll in college and move into a STEM field if they desired compared to the matched students. All gender/racial groups in the community school performed significantly higher than those in the matched group. Further, all gender/racial groups of students in the urban community school defied standard academic achievement drops common over time in middle school, and instead increase overall, math, and science grades from 6th to 8th grade.     

Predicting supercontinuum pulse collisions with simulations exhibiting temporal aliasing

Interactions between supercontinuum (SC) light pulses, produced by the propagation of rapidly sequenced picosecond pump laser pulses along a photonic crystal fiber, result in spectral broadening, which we attribute to interpulse soliton collisions. This phenomenon was measured experimentally, following our observation of spectral broadening in numerical simulations that exhibit so-called "pulse wraparound" or "temporal aliasing." This occurs in simulations with narrow time grids: as early parts of the SC pulse leave the computational time domain, they "reenter" at the beginning and so interact with later parts of the evolving SC pulse. We show that this provides an effective model to predict the experimentally observed spectral changes.     

Orlicz-Sobolev extensions and measure density condition

We study the extension properties of Orlicz-Sobolev functions both in Euclidean spaces and in metric measure spaces equipped with a doubling measure. We show that a set E⊂R satisfying a measure density condition admits a bounded linear extension operator from the trace space W1,Ψ(Rn)E_| to W1,Ψ(Rn). Then we show that a domain, in which the Sobolev embedding theorem or a Poincaré-type inequality holds, satisfies the measure density condition. It follows that the existence of a bounded, possibly non-linear extension operator or even the surjectivity of the trace operator implies the measure density condition and hence the existence of a bounded linear extension operator.     

Ion‐Pair Complexation with Dibenzo[21]Crown‐7 and Dibenzo[24]Crown‐8 bis‐Urea Receptors

Synthesis and ion‐pair complexation properties of novel ditopic bis‐urea receptors based on dibenzo[21]crown‐7 ( R¹ ) and dibenzo[24]crown‐8 ( R² ) scaffolds have been studied in the solid state, solution, and gas phase. In a 4:1 CDCl₃/[D₆]DMSO solution, both receptors clearly show positive heterotropic cooperativity toward halide anions when complexed with Rb⁺ or Cs⁺, with the halide affinity increasing in order I^?<Br^?<Cl^?. In solution, the rubidium complexes of both receptors have higher halide affinities compared to the caesium complexes. However, Rb⁺ and Cs⁺ complexes of R² show stronger affinities toward all the studied anions compared to the corresponding cationic complexes of R¹ . Similar selectivity of the receptors toward the studied ion pairs was also observed also in the gas phase by competition experiments with mass spectrometry. A total of eight crystal structures with different rubidium and caesium halides and oxyanions were obtained in addition to the crystal structure of R²?BaCl₂ . The selectivity observed in solution and in the gas phase is explainable by the conformational differences observed in the crystal structures of ion‐pair complexes with R¹ and R² . In the solid state, R¹ has an open conformation due to the asymmetric crown‐ether scaffold, whereas R² has a compact, folded conformation. Computational studies of the ion‐pair complexes of R² show that the interaction energies of the complexes increase in the order CsI<CsBr<CsCl<RbCl, supporting the selectivity observed in solution and the gas‐phase.     

An Immucillin‐Based Transition‐State‐Analogous Inhibitor of tRNA–Guanine Transglycosylase (TGT)

Shigellosis is one of the most severe diarrheal diseases worldwide without any efficient treatment so far. The enzyme tRNA–guanine transglycosylase (TGT) has been identified as a promising target for small‐molecule drug design. Herein, we report a transition‐state analogue, a small, immucillin‐derived inhibitor, as a new lead structure with a novel mode of action. The complex inhibitor synthesis was accomplished in 18 steps with an overall yield of 3 %. A co‐crystal structure of the inhibitor bound to Z. mobilis TGT confirmed the predicted conformation of the immucillin derivative in the enzyme active site.     

Enhancing engineering education in the elementary school

The Next Generation Science Standards emphasizes the inclusion of engineering practices throughout the K–12 science curriculum. Therefore, elementary educators need to be knowledgeable about engineering and engineering careers so that they can expose their students to engineering. The purpose of this study was to examine the effect of engineering professional development on in‐service elementary teachers’: (a) knowledge and perceptions regarding engineering, and (b) self‐efficacy of teaching engineering. This quantitative study revealed that even one professional development opportunity can help to alleviate some misconceptions about the work of engineers and what constitutes technology, as well as increase teachers’ confidence to teach engineering concepts.     

Development and validation of a 21st Century Skills Assessment: Using an iterative multimethod approach

In response to the call for more rigorously validated educational assessments, this study used an iterative multimethod validation process to develop and validate outcomes from the 21st Century Skills Assessment global rating scale. Qualitative and quantitative data sources were used to inform four types of validity evidence: content, response process, internal structure, and consequential. STEM experts and typical assessment users provided support for content, response process, and consequential validity evidence through focus group interviews and cognitive interviews. Psychometric findings suggest strong internal validity evidence for the assessment through high measures of internal consistency reliability, intra‐rater agreement, and test–retest reliability measures.     

The fundamental band ν2 of D2CO

The ν₂ band of D₂¹³CO in the region of 1570-1760 cm⁻¹ has been analyzed with high accuracy. The limits of the quantum numbers J and K_a are 50 and 16, respectively. The number of the assigned transitions is 3858. A local anharmonic resonance ν₂/2ν₄ at K_a =  8-12 was observed. The Watson’s A-reduced Hamiltonian and anharmonic resonance term were fitted to the observed transitions. The fit resulted in the band center and rotational parameters of the ν₂ band as well as the effective parameters for the 2ν₄ band and anharmonic resonance parameter. The rms deviation of the transitions in the ν₂ band was 0.000364 cm⁻¹.