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Public education in the United States has been undergoing a shift from an empirical tradition in which practices and policies are derived from research, practice, reflection, and implementation. In this empirical tradition, professionals embrace a culture and commitment to evidence-based practices (EBPs) and expect that practices and policies in the field are supported by rational, data-driven models. In this paper, we present an argument and three cases that illustrate how educators have been undergoing a gradual shift away from empiricism toward a de-evolution of EBP. We propose that this gradual shift is based on a political-social context, in which practices and policies are implemented using the language of an accountability model of reform, in which national and state regulations, and accreditation bodies, establish expectations often devoid of an empirical basis for the practices they mandate.

Abstract: We demonstrate the guiding principles behind simple two dimensional self‐assembly of MOF nanoparticles (NPs) and oleic acid capped iron oxide (Fe3O4) NCs into a uniform two‐dimensional bi‐layered superstructure. This self‐assembly process can be controlled by the energy of ligand–ligand interactions between surface ligands on Fe3O4 NCs and Zr6O4(OH)4(fumarate)6 MOF NPs. Scanning transmission electron microscopy (TEM)/energy‐dispersive X‐ray spectroscopy and TEM tomography confirm the hierarchical co‐assembly of Fe3O4 NCs with MOF NPs as ligand energies are manipulated to promote facile diffusion of the smaller NCs. First‐principles calculations and event‐driven molecular dynamics simulations indicate that the observed patterns are dictated by combination of ligand–surface and ligand–ligand interactions. This study opens a new avenue for design and self‐assembly of MOFs and NCs into high surface area assemblies, mimicking the structure of supported catalyst architectures, and provides a thorough fundamental understanding of the self‐assembly process, which could be a guide for designing functional materials with desired structure.

Marketing orders are government-supported cartels designed to help farmers by allowing them to set production quotas and quality standards. Given that, it is surprising that a growing number have been voluntarily terminated in recent decades by their constituent farmers. To better understand why, we construct a novel data set on the timing of initiation and termination of marketing orders active between 1974 and 2019 and estimate duration models to examine the impact of specific factors on marketing orders' probability of survival. We find that the most significant factor affecting marketing order persistence is whether the order had a corresponding marketing agreement. [ABSTRACT FROM AUTHOR]

Recent efforts in organic photovoltaics (OPVs) have been devoted to obtaining low-bandgap non-fullerene acceptors (NFAs) for high photocurrent generation. However, the low-lying lowest unoccupied molecular orbital (LUMO) level in narrow bandgap NFAs typically results in a small energy difference (ΔEDA) between the LUMO of the acceptor and the highest occupied molecular orbital (HOMO) of the donor, leading to low open-circuit voltage (VOC). The trade-off between ΔEDA and photocurrent generation significantly limits the simultaneous enhancement of both VOC and short-circuit current density (JSC). Here, we report a new medium-bandgap NFA, IDTT-T, containing a weakly electron-withdrawing N-ethyl thiabarbituric acid terminal group on each end of the indacenodithienothiophene (IDTT) core. When paired with a benchmark low-bandgap PTB7-th polymer donor, simultaneous enhancement of both ΔEDA and absorption spectral coverage was realized. The OPV devices yield a VOC of 1.01 V, corresponding to a low energy loss of 0.57 eV in around 10% efficiency single-junction NFA OPVs. The design demonstrates a working principle to concurrently increase ΔEDA and photocurrent generation for high VOC and PCE in bulk fullerene-free heterojunction OPVs.

High boiling-point solvent additives, such as 1,8-diiodooctane, have been widely used to tune nanoscale phase morphology for increased efficiency in bulk heterojunction organic solar cells. However, liquid-state solvent additives remain in the active films for extended times and later migrate or evaporate from the films, leading to unstable device performance. Here, a solid-state photoactive molecular mediator, namely N(BAI)3, is reported that could be employed to replace the commonly used solvent additives to tune the morphology of bulk heterojunction films for improved device performance. The N(BAI)3 mediator not only resides in the active films locally to fine tune the phase morphology, but also contributes to the additional absorption of the active films, leading to ∼11% enhancement of power conversion efficiency of P3HT:PC60BM devices. Comparative studies are carried out to probe the nanoscale morphologies using grazing incidence wide-angle X-ray scattering and complementary neutron reflectometry. The use of 1 wt% N(BAI)3 is found to effectively tune the packing of P3HT, presumably through balanced π-interactions endowed by its large conjugated π surface, and to promote the formation of a PC60BM-rich top interfacial layer. These findings open up a new way to effectively tailor the phase morphology by photoactive molecular mediators in organic photovoltaics.

We synthesized a two-dimensional (2D) crystalline covalent organic framework (sp2c-COF) that was designed to be fully π-conjugated and constructed from all sp2 carbons by C=C condensation reactions of tetrakis(4-formylphenyl)pyrene and 1,4-phenylenediacetonitrile. The C=C linkages topologically connect pyrene knots at regular intervals into a 2D lattice with π conjugations extended along both x and y directions and develop an eclipsed layer framework rather than the more conventionally obtained disordered structures. The sp2c-COF is a semiconductor with a discrete band gap of 1.9 electron volts and can be chemically oxidized to enhance conductivity by 12 orders of magnitude. The generated radicals are confined on the pyrene knots, enabling the formation of a paramagnetic carbon structure with high spin density. The sp2 carbon framework induces ferromagnetic phase transition to develop spin-spin coherence and align spins unidirectionally across the material.

We report controllable anisotropic light emission of photons originating from vertically aligned transition dipole moments in spun-cast films of CsPbBr3 nanocubes. By depositing films of nanocrystals on precoated substrates we can control the packing density and resultant radiation pattern of the emitted photons. We develop a technical framework to calculate the average orientation of light emitters, i.e., the angle between the transition dipole moment vector (TDM) and the substrate. This model is applicable to any emissive material with a known refractive index. Theoretical modeling indicates that oriented emission originates from an anisotropic alignment of the valence band and conduction band edge states on the ionic crystal lattice and demonstrates a general path to model the experimentally less accessible internal electric field of a nanosystem from the photoluminescent anisotropy. The uniquely accessible surface of the perovskite nanoparticles allows for perturbation of the normally isotropic emissive transition. The reported sensitive and tunable TDM orientation and control of emitted light will allow for applications of perovskite nanocrystals in a wide range of photonic technologies inaccessible to traditional light emitters.

Quinoidal structures incorporating expanded para-quinodimethane (p-QM) units have garnered great interest as functional organic electronic, optical, and magnetic materials. The direct use of the compact p-QM unit as an electronic building block, however, has been inhibited by the high reactivity conveyed by its biradical character. Herein, we introduce a stable p-QM variant, namely p-azaquinodimethane (p-AQM), that incorporates nitrogen atoms in the central ring and alkoxy substituents on the periphery to increase the stability of the quinoidal structure. The succinct synthesis from readily available precursors leads to regio- and stereospecific p-AQMs that can be readily integrated into the backbone of conjugated polymers. The quinoidal character of the p-AQM unit endows the resulting polymers with narrow band gaps and high carrier transport mobilities. The study of a series of copolymers employing different numbers of thiophene units revealed an unconventional trend in band gaps, which is distinct from the widely adopted donor-acceptor approach to tuning the band gaps of conjugated polymers. Theoretical calculations have shed light on the nature of this trend, which may provide a unique class of conjugated polymers with promising optical and electronic properties.

Conjugated block copolymers provide a pathway to achieve thermally stable nanostructured thin films for organic solar cells. We characterized the structural evolution of poly(3-hexylthiophene)-block-poly(diketopyrrolopyrrole-terthiophene) (P3HT-b-DPPT-T) from solution to nanostructured thin films. Aggregation of the DPPT-T block of P3HT-b-DPPT-T was found in solution by small-angle X-ray scattering with the P3HT block remaining well-solvated. The nanostructure in thin films was determined using a combination of wide and small-angle X-ray scattering techniques as a function of processing conditions. The structure in solution controlled the initial nanostructure in spin-cast thin films, allowing subsequent thermal annealing processes to further improve the ordering. In contrast to the results for thin films, nanostructural ordering was not observed in the bulk samples by small-angle X-ray scattering. These results suggest the importance of controlling solvent induced aggregation in forming nanostructured thin films of conjugated block copolymers.

An improved understanding of fundamental chemistry, electronic structure, morphology, and dynamics in polymers and soft materials requires advanced characterization techniques that are amenable to in situ and operando studies. Soft X-ray methods are especially useful in their ability to non-destructively provide information on specific materials or chemical moieties. Analysis of these experiments, which can be very dependent on X-ray energy and polarization, can quickly become complex. Complementary modeling and predictive capabilities are required to properly probe these critical features. Here, we present relevant background on this emerging suite of techniques. We focus on how the combination of theory and experiment has been applied and can be further developed to drive our understanding of how these methods probe relevant chemistry, structure, and dynamics in soft materials.

An improved understanding of fundamental chemistry, electronic structure, morphology, and dynamics in polymers and soft materials requires advanced characterization techniques that are amenable to in situ and operando studies. Soft X-ray methods are especially useful in their ability to non-destructively provide information on specific materials or chemical moieties. Analysis of these experiments, which can be very dependent on X-ray energy and polarization, can quickly become complex. Complementary modeling and predictive capabilities are required to properly probe these critical features. Here, we present relevant background on this emerging suite of techniques. We focus on how the combination of theory and experiment has been applied and can be further developed to drive our understanding of how these methods probe relevant chemistry, structure, and dynamics in soft materials.

Resonant Soft X-ray Scattering (RSoXS) was developed over the last a few years, and the first dedicated resonant soft X-ray scattering beamline for soft materials was constructed at the Advanced Light Source, LBNL. RSoXS combines soft X-ray spectroscopy with X-ray scattering and thus offers statistical information for 3D chemical morphology over a large length scale range from nanometers to micrometers. Using RSoXS to characterize multi-length scale soft materials with heterogeneous chemical structures, we have demonstrated that soft X-ray scattering is a unique complementary technique to conventional hard X-ray and neutron scattering. Its unique chemical sensitivity, large accessible size scale, molecular bond orientation sensitivity with polarized X-rays, and high coherence have shown great potential for chemically specific structural characterization for many classes of materials.

Previous attempts at modeling the neuro-cognitive mecha-nisms underlying word processing have used connectionist ap-proaches, but none has modeled spoken word architectures asthe input is presented in real-time. Hence, such models rely onthe ingenuity of the modeler to establish a mapping of real-time stimulus to the model’s input which may not preserveprocessing that happens during each time step. We present aneural field model which successfully replicates the effect ofimmediate auditory repetition of monosyllabic words and fitsit to a component of a well-studied mechanism for analyzinglanguage processing, the event-related potential (ERP). Thisrepresents a new modeling approach to studying the neuro-cognitive processes, one that is based on the bottom-up inter-action of real-time sensory information with higher-level cate-gories of cognitive processing.

Multi-walled carbon nanotubes (MWCNTs) were coated with silica by a sol-gel method to improve interfacial bonding and dispersion of nanotubes in the diglycidyl ether of bisphenol A (DGEBA) matrix. TEM and FE-SEM measurements showed that the silica shell was successfully coated on the surface of r-MWCNTs (as-received MWCNTs), and that the dispersion of MWCNT@SiO2 in the epoxy matrix and interfacial adhesion between MWCNTs and epoxy were improved through the silica shell formation. The effects of silica-coated multi-walled carbon nanotube (MWCNT@SiO2) addition on the curing behavior of epoxy resin, and on the physical and thermomechanical properties of epoxy composites, were studied. FT-IR measurements of different blends at different curing times indicated that the curing reaction was accelerated with the presence of MWCNTs and increased with the content of MWCNT@SiO2. DSC results confirmed that the value of activation energy decreased with the introduction of MWCNTs in the order of MWCNT@SiO2 < r-MWCNTs < epoxy. It was found that the thermal conductivity of epoxy composites were significantly enhanced by incorporation of MWCNT@SiO2, relative to composites with r-MWCNTs, while the values of the glass transition temperature slightly increased, and the high electrical resistivity of these composites was retained overall.

Carbon nanotubes (CNTs) functionalized by a nanothin poly(dopamine) (PDA) layer were produced by a one-pot, nondestructive approach, with direct polymerization of dopamine on the CNT surface. The thickness of the PDA layer can be well-controlled by the reaction time and the proportion of dopamine, and this thickness is found to be the key factor in controlling the dispersion of CNTs and the extent of the interfacial interactions between the CNT@PDA and epoxy resin. SEM results indicated that the dispersion of CNTs in epoxy was improved significantly by coating a nanothin PDA layer onto the CNT surface. In agreement with this finding, the CNTs functionalized with the thinnest PDA layer provided the best mechanical and thermal properties. This result confirmed that a thinner PDA layer could provide optimized interfacial interactions between the CNT@PDA and epoxy matrix and weaken the self-agglomeration of CNTs, which led to an improved effective stress and heat transfer between the CNTs and the polymer matrix.

As managers of agricultural and natural resources are confronted with uncertainties in global change impacts, the complexities associated with the interconnected cycling of nitrogen, carbon, and water present daunting management challenges. Existing models provide detailed information on specific sub-systems (e.g., land, air, water, and economics). An increasing awareness of the unintended consequences of management decisions resulting from interconnectedness of these sub-systems, however, necessitates coupled regional earth system models (EaSMs). Decision makers’ needs and priorities can be integrated into the model design and development processes to enhance decision-making relevance and “usability” of EaSMs. BioEarth is a research initiative currently under development with a focus on the U.S. Pacific Northwest region that explores the coupling of multiple stand-alone EaSMs to generate usable information for resource decision-making. Direct engagement between model developers and non-academic stakeholders involved in resource and environmental management decisions throughout the model development process is a critical component of this effort. BioEarth utilizes a bottom-up approach for its land surface model that preserves fine spatial-scale sensitivities and lateral hydrologic connectivity, which makes it unique among many regional EaSMs. This paper describes the BioEarth initiative and highlights opportunities and challenges associated with coupling multiple stand-alone models to generate usable information for agricultural and natural resource decision-making.

Cost-effective, solution-processable organic photovoltaics (OPV) present an interesting alternative to inorganic silicon-based solar cells. However, one of the major remaining challenges of OPV devices is their lack of long-term operational stability, especially at elevated temperatures. The synthesis of a fullerene dumbbell and its use as an additive in the active layer of a PCDTBT:PCBM-based OPV device is reported. The addition of only 20 % of this novel fullerene not only leads to improved device efficiencies, but more importantly also to a dramatic increase in morphological stability under simulated operating conditions. Dynamic secondary ion mass spectrometry (DSIMS) and TEM are used, amongst other techniques, to elucidate the origins of the improved morphological stability.

The purpose of this study was to investigate the effectiveness of training special education teachers in the process of functional behavioral assessment (FBA) and subsequent development of recommendations to promote behavior change. An original evaluation instrument was developed that included measures of special education teachers' knowledge of function of problem behavior and their ability to generate recommendations to promote behavior change. The instrument was distributed to elementary, middle, and high school special education teachers in a large urban school district. Teachers trained by the school district in the FBA process were compared to untrained teachers. The study incorporated a post-test only design, with data analyzed using a factorial ANOVA. Those teachers who were trained in the district FBA program answered multiple-choice questions related to the function of problem behavior more accurately than those who did not receive training. There was no significant difference between trained and untrained teachers on their ability to make recommendations to promote behavior change. The results of this study have implications for the development of initial and sustained training efforts for teachers in functional behavioral assessment methods. (Contains 6 tables.)

This article illustrates (a) 2 recent innovations in the changing criterion research design, (b) how these innovations apply to research and practice in special education, and (c) how clinical needs influence design features of the changing criterion design. The first innovation, the range-bound changing criterion, is a very simple variation of the classic changing criterion design. The classic version uses a single criterion for each stepwise intervention phase, whereas the range-bound version uses a range criterion--that is, an upper and lower limit for each intervention phase. The second innovation, the distributed criterion, combines elements of the changing criterion, multiple-baseline, and ABAB designs. It is well suited to contexts where students must multitask--that is, allocate, prioritize, and adjust time and effort to complete multiple tasks in response to changing environmental demands. These two innovations expand options available to researchers who use single-case research designs to investigate questions of interest in special education.