Book Reviews

International Environmental Law; The Impact of Inflation and Deflation on Privaye Legal Obligations; The International and National Protection of Movable Cultural Propert

A bipyridine-ligated zinc(II) complex with bridging flavonolate ligation: synthesis, characterization, and visible-light-induced CO release reactivity

Metal-flavonolate compounds are of significant current interest as synthetic models for quercetinase enzymes and as bioactive compounds of importance to human health. Zinc-3-hydroxyflavonolate compounds, including those of quercetin, kampferol, and morin, generally exhibit bidentate coordination to a single ZnII center. The bipyridine-ligated zinc-flavonolate compound reported herein, namely bis(μ-4-oxo-2-phenyl-4H-chromen-3-olato)-κ3O3:O3,O4;κ3O3,O4:O3-bis[(2,2′-bipyridine-κ2N,N′)zinc(II)] bis(perchlorate), {[Zn2(C15H9O3)2(C10H8N2)2](ClO4)2}n, (1), provides an unusual example of bridging 3-hydroxyflavonolate ligation in a dinuclear metal complex. The symmetry-related ZnII centers of (1) exhibit a distorted octahedral geometry, with weak coordination of a perchlorate anion trans to the bridging deprotonated O atom of the flavonolate ligand. Variable-concentration conductivity measurements provide evidence that, when (1) is dissolved in CH3CN, the complex dissociates into monomers. 1H NMR resonances for (1) dissolved in d6-DMSO were assigned via HMQC to the H atoms of the flavonolate and bipyridine ligands. In CH3CN, (1) undergoes quantitative visible-light-induced CO release with a quantum yield [0.004 (1)] similar to that exhibited by other mononuclear zinc-3-hydroxyflavonolate complexes. Mass spectroscopic identification of the [(bpy)2Zn(O-benzoylsalicylate)]+ ion provides evidence of CO release from the flavonol and of ligand exchange at the ZnII center.A bipyridine-ligated zinc-flavonolate complex exhibiting bridging flavonolate coordination has been characterized by single-crystal X-ray crystallography. In acetonitrile, this compound dissociates into monomers and undergoes visible-light-induced CO release. © International Union of Crystallography, 2017

Teachers’ perspectives on the Kindergarten Readiness Assessment in year 2: Easier to administer but what role can it play in instruction?

In this white paper, we present the results of a survey completed by teachers from across Ohio concerning their perceptions of Ohio’s Kindergarten Readiness Assessment (KRA). We examined teachers’ perceptions during year 2 of KRA implementation and compared those results to findings from a similar survey completed in year 1 of the assessment implementation. Over 3,000 Ohio public school kindergarten teachers were invited to complete the survey; of which 841 responded. In year 2, teachers reported that administering the KRA was easier, compared to year 1. However, they expressed concerns that the assessment took too long to administer, distracted from creating a classroom community, and decreased instructional time. Similar to findings from year 1, teachers reported that the assessment was not useful for guiding instruction or otherwise benefiting students; yet, teachers did report an increase in using the KRA to identify students at risk for later academic problems. In contrast to year 1, teachers seemed to better understand the purposes of the assessment although there were still some remaining misconceptions. Overall, despite some changes in perceptions, teachers continued to express concerns with the KRA’s implementation and remained unclear as to its role in improving instruction or outcomes for students

Nitrogen fixation by the savanna tree Philenoptera violacea (Klotzsch) Schrire (Apple leaf) of different ages in a semi-arid riparian landscape

AbstractThe acquisition of nitrogen for growth and maintenance is essential for plants, and having multiple strategies for that acquisition is especially important for those colonizing nutrient poor substrates. Philenoptera violacea (Apple leaf) is a prominent tree in nutrient poor savanna and alluvial soils near rivers in southern Africa, where nutrient availabilities are highly variable in space and time. We investigated nitrogen fixation in P. violacea within riparian corridors flanking the Sabie River in Kruger National Park (KNP) in the Lowveld in northeastern South Africa using the natural 15N abundance technique. Results indicated that P. violacea fixes atmospheric nitrogen and this varies with life history stage. We found that foliar δ15N levels were significantly lower in all life stage classes of P. violacea compared with the reference plant D. mespiliformis growing in open riparian forest. In addition δ15N values were significantly different within the different life stages of P. violacea with the leaves of saplings and juvenile plants having significantly lower δ15N levels than mature plants. While δ15N values increased with age, foliar nitrogen concentration values declined, with leaves from sapling P. violacea having significantly higher total nitrogen than adults and juveniles, which were in turn significantly higher than juvenile D. mespiliformis. However, foliar δ15N levels in seedlings of P. violacea growing in a high nutrient environment in flood debris piles did not differ from levels recorded in seedlings of the reference tree. This study confirms that P. violacea is able to fix nitrogen, but it is dependant on soil conditions and the life stage of the trees

Gestión de conocimiento para acelerar el aprendizaje de segundo idioma en adultos

El documento articula los procesos y resultados de un proyecto dedicado a la aceleración del aprendizaje de un segundo idioma en adultos, enmarcado en una estrategia de gestión de conocimiento en una universidad en Guadalajara, Jalisco. La problemática que enfrentan los adultos al aprender un segundo idioma y la necesidad de atenderla de un modo diferente, surgió de entrevistas entre maestros y alumnos de niveles principiantes del idioma inglés, combinado con las observaciones y experiencia propia en la docencia. El punto de partida fue la necesidad de desarrollar un instrumento que permitiera probar una hipótesis sobre cómo la comprensión de idioma materno podría servir como estructura para el aprendizaje de un nuevo idioma. Una investigación preliminar concluyó que un factor común e importante, entre las muchas barreras que afectan a los aprendices adultos de un segundo idioma, consiste en el poco conocimiento explícito que poseen acerca de su lengua materna. De esta observación se derivó la hipótesis que la falta de ese conocimiento explícito les impedía adquirir un conocimiento explícito del segundo idioma. El instrumento se desarrolló por medio de la colaboración entre tres maestros de la universidad, los cuales desarrollaron un mapeo para clarificar los objetivos y los caminos para lograr una determinación de la hipótesis y a partir del cual el gestor del conocimiento materializó los hallazgos en un taller de cuatro horas diseñado para estimular el análisis del idioma nativo, principalmente por medio del reconocimiento de patrones en su gramática básica, como herramienta metacognitiva para aplicar a la exploración de un segundo idioma.ITESO, A. C

Teachers’ experiences with a state-mandated kindergarten readiness assessment

This study used an embedded mixed method design to examine teachers’ experiences with a state-mandated kindergarten readiness assessment during its inaugural year. Participants were 143 kindergarten teachers from one county in a Midwestern state. In general, teachers did not perceive the Kindergarten Readiness Assessment as useful for one of its intended purposes of guiding instruction. Our findings did not indicate an adversity to assessment in general. Rather, perceptions that the new KRA was less useful for practice seemed to stem from administration issues, problems with the content assessed by the KRA, and participants’ misunderstandings regarding the purpose of the KRA. Furthermore, participants reported that the KRA took away valuable time needed to help students adjust to their first time in formal schooling and needed to create a classroom community. Implications for creating and implementing kindergarten readiness and other assessments as well as preparing teachers to use readiness assessments are discussed

Using the new Kindergarten Readiness Assessment: What do teachers and principals think?

This white paper presents the results of a survey completed by teachers and principals in central Ohio concerning their perceptions of Ohio’s new Kindergarten Readiness Assessment (KRA) during its inaugural implementation year. All kindergarten teachers and principals in Franklin County public elementary schools were invited to complete the survey; 150 responded. Although teachers and principals generally reported using assessments, including the previous state-mandated KRA-L screening tool, to guide their instructional decisions, the majority of participants did not perceive that the KRA, in particular, was useful for guiding instruction. Moreover, teachers reported that administering the KRA took away valuable time needed to help students adjust to learning in a formal school setting and create a classroom community. Administration issues, lack of access to the data, redundancy or incompleteness of KRA data, and misconceptions about the purpose of the KRA all seemed to contribute to participants’ dissatisfaction with the KRA. Overall, it seems that teachers are not using the KRA as intended. Our findings do not indicate an adversity to assessment in general. Rather, negative perceptions and/or lack of use seem to be tied to a misunderstanding of the purpose of the KRA and administration issues

Failure Investigation of an Intra-Manifold Explosion in a Horizontally-Mounted 870 lbf Reaction Control Thruster

In June 2010, an 870 lbf Space Shuttle Orbiter Reaction Control System Primary Thruster experienced an unintended shutdown during a test being performed at the NASA White Sands Test Facility. Subsequent removal and inspection of the thruster revealed permanent deformation and misalignment of the thruster valve mounting plate. Destructive evaluation determined that after three nominal firing sequences, the thruster had experienced an energetic event within the fuel (monomethylhydrazine) manifold at the start of the fourth firing sequence. The current understanding of the phenomenon of intra-manifold explosions in hypergolic bipropellant thrusters is documented in literature where it is colloquially referred to as a ZOT. The typical ZOT scenario involves operation of a thruster in a gravitational field with environmental pressures above the triple point pressure of the propellants. Post-firing, when the thruster valves are commanded closed, there remains a residual quantity of propellant in both the fuel and oxidizer (nitrogen tetroxide) injector manifolds known as the "dribble volume". In an ambient ground test configuration, these propellant volumes will drain from the injector manifolds but are impeded by the local atmospheric pressure. The evacuation of propellants from the thruster injector manifolds relies on the fluids vapor pressure to expel the liquid. The higher vapor pressure oxidizer will evacuate from the manifold before the lower vapor pressure fuel. The localized cooling resulting from the oxidizer boiling during manifold draining can result in fuel vapor migration and condensation in the oxidizer passage. The liquid fuel will then react with the oxidizer that enters the manifold during the next firing and may produce a localized high pressure reaction or explosion within the confines of the oxidizer injector manifold. The typical ZOT scenario was considered during this failure investigation, but was ultimately ruled out as a cause of the explosion. Converse to the typical ZOT failure mechanism, the failure of this particular thruster was determined to be the result of liquid oxidizer being present within the fuel manifold

Advancements in the Synthesis of Polyoxygenated Oxepanes and Thiepanes for Applications to Natural Products

Oxepanes are central motifs and tenants of many biologically important molecules, and their synthetic construction often presents a challenge to chemists due to consequential entropic and enthalpic barriers that have limited the synthetic toolbox to access these seven-membered oxacycles. This review covers the breadth of synthetic methods to afford the oxepane/thiepane moiety, with a focus on polyoxygenated oxepanes and includes radical cyclizations, Lewis acid-mediated cyclizations, ring closing-metathesis, Nicholas-Ferrier rearrangement, homologations, and ring-expansion strategies. Implementation of these tactics towards sugar-based and non-sugar based (de novo) approaches is presented alongside their extensive application to the total synthesis of several complex polyoxygenated oxepane-containing natural products, which are also highlighted