The Causes and Consequences of Student Discipline Disparities

As part of the Brookings Scholar Lecture Series, Brookings Mountain West invites you to a lecture titled The Causes and Consequences of Student Discipline Disparities by Fellow in Governance Studies, Brown Center on Education Policy, Jon Valant. Students of color and students from low-income families are suspended or expelled from school at much higher rates than their white and non-poor peers. This lecture presented data on discipline disparities. It considered explanations such as discrimination in how schools punish students and whether majority-minority and majority-white schools approach discipline differently. This discussion is placed in the context of local, state, and federal efforts to address student disparities. This included assessing evidence on alternative approaches to student discipline (such as restorative justice programs) and their potential to disrupt school-to-prison pipelines

On stoichiometry and intermixing at the spinel/perovskite interface in CoFe2O4/BaTiO3 thin films

The performance of complex oxide heterostructures depends primarily on the interfacial coupling of the two component structures. This interface character inherently varies with the synthesis method and conditions used since even small composition variations can alter the electronic, ferroelectric, or magnetic functional properties of the system. The focus of this article is placed on the interface character of a pulsed laser deposited CoFe2O4/BaTiO3 thin film. Using a range of state-of-the-art transmission electron microscopy methodologies, the roles of substrate morphology, interface stoichiometry, and cation intermixing are determined on the atomic level. The results reveal a surprisingly uneven BaTiO3 substrate surface formed after the film deposition and Fe atom incorporation in the top few monolayers inside the unit cell of the BaTiO3 crystal. Towards the CoFe2O4 side, a disordered region extending several nanometers from the interface was revealed and both Ba and Ti from the substrate were found to diffuse into the spinel layer. The analysis also shows that within this somehow incompatible composite interface, a different phase is formed corresponding to the compound Ba2Fe3Ti5O15, which belongs to the ilmenite crystal structure of FeTiO3 type. The results suggest a chemical activity between these two oxides, which could lead to the synthesis of complex engineered interfaces

Increasing Survey Data Quality Using Screening Validity Questions

Self-report surveys are used frequently in fraternity organizations to collect information from students. A lack of thoughtful or truthful answers on survey instruments threatens the validity of results. The current study evaluates if identifying and omitting invalid responders using screening validity questions improves data quality on two scales among fraternity men: the Illinois Rape Myth Acceptance and the Conformity to Masculinity Norms Inventory. Results indicate invalid responders bias results suggesting using screen validity questions improves data quality. This strategy can help fraternity professionals ensure their programming responds more closely to their member perceptions, attitudes, and experiences

Solid Freeform Fabrication Based on Micro-Plasma Powder Deposition

This paper presents a solid freeform fabrication (SFF) technique based on micro-plasma powder deposition (MPPD). The relationship between the geometric features of the deposited layers and the welding parameters is investigated. The arc length is controlled through the monitoring of the arc voltage. The result of building parts with functionally graded components by the MPPD process is shown as well. The microstructure and the properties of the deposited layers are analyzed. The experimental results show that the MPPD process is a promising welding-based solid freeform fabrication technology.Mechanical Engineerin

Cation Ordering in Pb(Mg\u3csub\u3e1/3\u3c/sub\u3eNb\u3csub\u3e2/3\u3c/sub\u3e)O\u3csub\u3e3\u3c/sub\u3e–Pb(Sc\u3csub\u3e1/2\u3c/sub\u3eNb\u3csub\u3e1/2\u3c/sub\u3e)O\u3csub\u3e3\u3c/sub\u3e (PMN–PSN) Solid Solutions

Extended thermal annealing treatments were used to modify the B-site cation order in the (1 - x)PMN–xPSN perovskite system (where PMN is lead magnesium niobate, Pb(Mg1/3Nb2/3)O3, and PSN is lead scandium niobate, Pb(Sc1/2Nb1/2)O3). Extensive 1:1 ordering could be induced in compositions with x ≧ 0.1. The substitution of PSN into PMN produced a large increase in the thermal stability of the 1:1 ordered phase, with the maximum disordering temperature of ~1360oC being observed for the x = 0.5 composition. By monitoring the change in the degree of order with temperature, the order–disorder boundary for the PMN–PSN system was established and the transition temperature for pure PMN was estimated to be ~950oC. The changes in stability across the system were consistent with the random-site description of the cation order. The change in enthalpy associated with the ordering was affected by the size difference of the two ordered cation sites and by the size and charge mismatch of the metal cations that occupy the random-site position

First-principles characterization of Mg low-index surfaces: Structure, reconstructions, and surface core-level shifts

In this paper, first-principles calculations provide structural characterization of three low-index Mg surfaces - Mg(0001), Mg(1010), and Mg(1120) - and their respective surface core-level shifts (SCLSs). Inspired by the close similarities between Be and Mg surfaces, we also explore the reconstruction of Mg(1120). Through the calculation of surface energies and the use of the angular-component decomposed density of states, we show that reconstructions are likely to occur at the Mg(1120) surface, similarly to what was found earlier for Be(1120). Indeed, the surface energy of some of the explored reconstructions is slightly lower than that of the unreconstructed surface. In addition, because of lattice symmetry, the morphology of the unreconstructed surface (1120) results in a steplike zig-zag chain packing, with topmost chains supporting a resonant, quasi-one-dimensional (1D), partially filled electronic state. As the presence of partially filled quasi-1D bands is a necessary condition for Peierls-like dimerization, we verify that the undimerized surface chain remains stable with respect to it. Some of the reconstructions, namely, the 2 71 and 3 71 added row reconstructions, induce a stronger relaxation of the topmost chains, increasing the coupling with lower layers and thus significantly damping the quasi-1D character of this state. The original approach followed offers a common and general framework to identify quasi-1D bands - even in the case of resonant electronic surface states - and to meaningfully compare calculated and measured SCLSs even in the presence of multicomponent peak contributions

Novel temperature stable high-ε r microwave dielectrics in the Bi 2 O 3 –TiO 2 –V 2 O 5 system

In the present work, a series of low temperature firing (1 − x)BiVO4–xTiO2 (x = 0.4, 0.50, 0.55 and 0.60) microwave dielectric ceramics was prepared using traditional solid state reaction method. From back-scattered electron images (BEI), X-ray diffraction (XRD) and energy dispersive analysis (EDS), there was negligible reaction between BiVO4 and TiO2 at the optimal sintering temperature ∼900 °C. As x increased from 0.4 to 0.60, permittivity (εr) increased from 81.8 to 87.7, quality factor value (Qf) decreased from 12 290 to 8240 GHz and temperature coefficient (TCF) shifted from −121 to +46 ppm per °C. Temperature stable microwave dielectric ceramic was obtained in 0.45BiVO4–0.55TiO2 composition sintered at 900 °C with a εr ∼ 86, a Qf ∼ 9500 GHz and a TCF ∼ −8 ppm per °C. Far-infrared reflectivity fitting indicated that stretching of Bi–O and Ti–O bonds in this system dominated dielectric polarization. This series of ceramics are promising not only for low temperature co-fired ceramic (LTCC) technology but also as substrates for physically and electrically small dielectrically loaded micro-strip patch antennas

Chemodiversity of Exudate Flavonoids in Seven Tribes of Cichorioideae and Asteroideae (Asteraceae) §

Members of several genera of Asteraceae, belonging to the tribes Mutisieae, Cardueae, Lactuceae (all subfamily Cichorioideae), and of Astereae, Senecioneae, Helenieae and Heliantheae (all subfamily Asteroideae) have been analyzed for chemodiversity of their exudate flavonoid profiles. The majority of structures found were flavones and flavonols, sometimes with 6-and/or 8-substitution, and with a varying degree of oxidation and methylation. Flavanones were observed in exudates of some genera, and, in some cases, also flavonol-and flavone glycosides were detected. This was mostly the case when exudates were poor both in yield and chemical complexity. Structurally diverse profiles are found particularly within Astereae and Heliantheae. The tribes in the subfamily Cichorioideae exhibited less complex flavonoid profiles. Current results are compared to literature data, and botanical information is included on the studied taxa