The centralization of education governance has mixed results for student achievement across U.S. states

Much of the debate over school improvement in the U.S. over the past two decades has focused on specific policy reforms. Using findings from new research, which examines how states govern education, Paul Manna argues that the amount of centralization in a state’s system can have an equally important role. He finds that states with more centralized political structures, which allow governors to appoint top education officials, had smaller achievement gaps. Those that were more administratively centralized by maintaining fewer school districts also had lower achievement gaps, but reduced achievement overall

Developing Excellent School Principals To Advance Teaching and Learning: Considerations for State Policy

School principals are "invaluable multipliers of teaching and learning in the nation's schools," according to this report by political scientist Paul Manna, but to date it's been unclear what state policymakers could do to boost their effectiveness. Drawing from sources including the experiences of states that have focused on developing stronger principal policy, this report aims to fill that gap by offering guidance in the form of three sets of considerations for those who want to take action. The first is an appraisal of the principal's current status on the list of state priorities and the rationale for placing the principal higher on the agenda, such as the fact that principals can have a powerful effect on the classroom. The second is an examination of six policy levers that states can pull:Adopting principal leadership standards into state law and regulation;Recruiting aspiring principals into the profession;Approving and overseeing principal preparation programs;Licensing new and veteran principals;Supporting principals' growth with professional development; andEvaluating principals.The third is an assessment of four important contextual matters for the state: its web of institutions responsible education governance and the interaction among them; its diversity of urban, suburban and rural locales; its capacity, along with the capacities of its communities, to carry out new policies; and its mandates already affecting principals

How Can State Policy Support Local School Districts as They Develop Principal Pipelines?

State policy contributes to the overall environment that affects how school principals emerge, develop, and lead their schools. School districts are most proximate to the work that principals do and therefore have the most direct, regular engagement with candidates for the principalship, principals in training, and principals on the job. As a result, to understand the multiple processes that bring excellent principals into schools and support them on the job—metaphorically, the "principal pipeline"—one must account for local and state forces. This paper examines the nexus where state and local actions come together to develop and support excellent principals. It describes key policy levers that state officials can pull as they support the work of local officials as they work to develop comprehensive and aligned principal pipelines. Along the way, the paper offers key questions that state and local officials and their policy partners can ask in order to assess their strengths and weaknesses as they work together, leveraging their comparative advantages, to ensure that all schools have excellent principals

Phosphoinositides, kinases and adaptors coordinating endocytosis in Trypanosoma brucei

In the kinetoplastid parasite Trypanosoma brucei clathrin-mediated endocytosis is essential for survival and aids immune evasion in the mammalian host. The formation of endocytic clathrin coated vesicles in T. brucei is via a unique mechanism owing to an evolutionarily recent loss of the adaptor protein (AP)2 complex, a central hub in endocytic vesicle assembly. Despite this loss, recent studies examining endocytic clathrin coat assembly have highlighted a high degree of conservation between trypanosomes and their mammalian hosts. In particular phosphatidylinositol 4,5-bisphosphate (PI(4,5)P(2)) and its putative effectors, TbCALM and TbEpsinR, are central to clathrin-mediated endocytosis in the trypanosome, just as they are in animal cells. In addition to providing insights into the cell biology of T. brucei, these studies also suggest an ancient, possibly pan-eukaryotic connection between PtdIns(4,5)P(2) and endocytosis

Ferromagnetism or slow paramagnetic relaxation in Fe-doped Li3_3N?

We report on isothermal magnetization, M\"ossbauer spectroscopy, and magnetostriction as well as temperature-dependent alternating-current (ac) susceptibility, specific heat, and thermal expansion of single crystalline and polycrstalline Li$_2$(Li$_{1-x}$Fe$_x$)N with $x = 0$ and $x \approx 0.30$. Magnetic hysteresis emerges at temperatures below $T \approx 50\,$K with coercivity fields of up to $\mu_0H = 11.6\,$T at $T = 2\,$K and magnetic anisotropy energies of $310\,$K ($27\,$meV). The ac susceptibility is strongly frequency dependent ($f\,=\,10$--$10,000\,$Hz) and reveals an effective energy barrier for spin reversal of $\Delta E \approx 1100\,$K. The relaxation times follow Arrhenius behavior for $T > 25\,$K. For $T < 10\,$K, however, the relaxation times of $\tau \approx 10^{10}\,$s are only weakly temperature-dependent indicating the relevance of a quantum tunneling process instead of thermal excitations. The magnetic entropy amounts to more than $25\,$J mol$^{-1}_{\rm Fe}\,$K$^{-1}$ which significantly exceeds $R$ln2, the value expected for the entropy of a ground state doublet. Thermal expansion and magnetostriction indicate a weak magneto-elastic coupling in accordance with slow relaxation of the magnetization. The classification of Li$_2$(Li$_{1-x}$Fe$_x$)N as ferromagnet is stressed and contrasted with highly anisotropic and slowly relaxing paramagnetic behavior.Comment: 12 pages, 10 figure

Structural and magnetic characterization of two tetranuclear Cu(II) complexes with closed‐cubane‐like core framework

Two novel tetranuclear Cu(II) complexes [Cu4(L1)4]·3(H2O) (1) and [Cu4(H2L2)4(H2O)4] (2) ( H2L1 = (E)-2-((1-hydroxybutan-2-ylimino)methyl)phenol; H4L2 = 2-((2-hydroxy-3-methoxybenzylidene)amino)-2-hydroxymethylpropane-1,3-diol) were synthesized from the self-assembly of copper(II) perchlorate and the tridentate Schiff base ligands. Both complexes crystallize in the tetragonal system with space group I 41/a and form tetranuclear species with closed-cubane like core framework. Both the complexes possess a S4 axis but of different stereochemistry due to the different arrangement of the ligands about the copper ions. Variable temperature magnetic susceptibility measurements indicate an overall weak antiferromagnetic exchange coupling in 1, while ferromagnetic exchange coupling in 2. In agreement with their closed-cubane structure, the magnetic behavior of the two complexes have been studied by employing the isotropic spin Hamiltonian of type H = J1 (S1S3 + S1S4 + S2S3 + S2S4) - J2 (S1S2 + S3S4) (J1 describes the magnetic exchange coupling between the four Cu(II) pairs with short Cu···Cu distances, while J2 characterizes the magnetic exchange coupling between the remaining two intermetallic pairs with long distances). The PHI program was used to study their magnetic behavior. A good agreement between the experimental and fitted curves was found with the following parameters: g = 2.14, J1 = -20.3 cm-1 and J2 = 0 cm-1 for 1 and g = 2.10, J1 = 101.1 cm-1 and J2 = -51.5 cm-1 for 2

First-principles modeling of unpassivated and surfactant-passivated bulk facets of wurtzite CdSe: a model system for studying the anisotropic growth of CdSe nanocrystals.

Equilibrium geometries, surface energies, and surfactant binding energies are calculated for selected bulk facets of wurtzite CdSe with a first-principles approach. Passivation of the surface Cd atoms with alkyl phosphonic acids or amines lowers the surface energy of all facets, except for the polar 0001 facet. On the nonpolar facets, the most stable configuration corresponds to full coverage of surface Cd atoms with surfactants, while on the polar 0001 facet it corresponds only to a partial coverage. In addition, the passivated surface energies of the nonpolar facets are in general lower than the passivated polar 0001 facet. Therefore, the polar facets are less stable and less efficiently passivated than the nonpolar facets, and this can rationalize the observed anisotropic growth mechanism of wurtzite nanocrystals in the presence of suitable surfactants

Structural and magnetic characterization of three tetranuclear Cu(II) complexes with face-sharing-dicubane/double-open-cubane like core framework

Three novel tetranuclear copper(II) complexes namely [Cu4(L1)4]∙(dmf) (1), [Cu4(L1)4] (2) and [Cu4(L2)2(HL2)2(H2O)2]∙2(ClO4)∙6(H2O) (3) (H2L1, (E)-2-((1-hydroxybutan-2-ylimino)methyl)phenol; H2L2, (E)-2-((1-hydroxybutan-2-ylimino)methyl)-6-methoxyphenol)) were synthesised from the self-assembly of copper(II) perchlorate and the tridentate Schiff base ligands. The structural determination reveals that complex 1 crystallizes in the monoclinic system with space group C2/c, whereas both the complexes 2 and 3 crystallize in the triclinic system with space group P-1. Complexes 1 and 2 possess face-sharing dicubane core, on the other hand complex 3 has double open cubane core structure. The copper(II) ions in the cubane core are in distorted square planar geometries, and weak π¿π and C-H¿π interactions lead to formation of a 2D supramolecular architecture for complexes 1 and 2. At room temperature complexes 1, 2 and 3, exhibit fluorescence with a quantum yield (Φs) of 0.47, 0.49 and 0.38, respectively. Variable temperature magnetic susceptibility measurements in the range 2-300 K indicate an overall weak antiferromagnetic exchange coupling in all complexes. The PHI program was used to study their magnetic behaviour. In agreement with their face-sharing dicubane structure, a Hamiltonian of the type H = - J1(S1S2+S1S2'+S1'S2+S1'S2') - J2S1S1', where S1 = S1' = S2 = S2' = SCu = 1/2, was used for studying complexes 1 and 2. Simulations performed suggest magnetic exchange constants with values close to J1 = -20 cm-1 and J2 = 0 cm-1 for these complexes. On the other hand, the spin Hamiltonian H = - J1(S1S4+S2S3) - J2(S1S3+S2S4) - J3S1S2, where S1 = S2 = S3 = S4 = SCu = 1/2, was used to study the magnetic behaviour of the double open cubane core of complex 3 and a good agreement between the experimental and simulated results was found by using the parameters g1 = g2 = 2.20, g3 = g4 = 2.18, J1 = -36 cm-1, J2 = -44 cm-1 and J3 = 0 cm-1

Preparation and Characterization of Nano structured Materials from Fly Ash: A Waste from Thermal Power Stations, by High Energy Ball Milling

The Class F fly ash has been subjected to high energy ball milling and has been converted into nanostructured material. The nano structured fly ash has been characterized for its particle size by using particle size analyzer, specific surface area with the help of BET surface area apparatus, structure by X-ray diffraction studies and FTIR, SEM and TEM have been used to study particle aggregation and shape of the particles. On ball milling, the particle size got reduced from 60 μm to 148 nm by 405 times and the surface area increased from 0.249 m2/gm to 25.53 m2/gm i.e. by more than 100%. Measurement of surface free energy as well as work of adhesion found that it increased with increased duration of ball milling. The crystallite was reduced from 36.22 nm to 23.01 nm for quartz and from 33.72 nm to 16.38 nm for mullite during ball milling to 60 h. % crystallinity reduced from 35% to 16% during 60 h of ball milling because of destruction of quartz and hematite crystals and the nano structured fly ash is found to be more amorphous. Surface of the nano structured fly ash has become more active as is evident from the FTIR studies. Morphological studies revealed that the surface of the nano structured fly ash is more uneven and rough and shape is irregular, as compared to fresh fly ash which are mostly spherical in shape

Double mu(2)-(phenoxido)-bridged dinuclear and polynuclear nickel(II) complexes: magnetic properties and DNA/protein interaction

One dinuclear and one 1D polymeric nickel(II) complex, namely {[Ni2(HL)2(pa)2(H2O)2]·DMF} (1) and {[Ni2(HL)2(ppda)(H2O)2]·DMF·H2O}n (2) (H2L = (E)-2-((1-hydroxybutan-2-ylimino)methyl)phenol, pa = 3-phenylacrylate, ppda = p-phenylenediacrylate) have been synthesized and characterized by X-ray single crystal structure determination. Complex 1 is double phenoxo-bridged dinuclear Ni(II) complex, whereas complex 2 is a 1D polynuclear chain where double phenoxo-bridged dinuclear units are connected through bridging ppda ligands. The variable temperature magnetic behavior of the complexes was studied using the Hamiltonian H = −JS1S2, S1 = S2 = SNi and confirms the presence of an overall antiferromagnetic interaction in both complexes. Good agreement between the experimental and simulated curves were found using the parameters: gNi = 2.15, DNi = 4.0 cm−1 and JNi-Ni = −0.60 cm−1 for 1, and gNi = 2.15, DNi = 4.8 cm−1 and JNi-Ni = −3 cm−1 for 2. The interactions of the complexes with CT-DNA were investigated using UV-Vis absorption and fluorescence spectroscopic methods and they show that both the complexes interact with CT-DNA. The intrinsic binding constants values for interaction with CT-DNA are 3.9(±0.10) × 105 and 3.43(±0.09) × 105 M−1 for 1 and 2, respectively. The interactions of the complexes with bovine serum albumins (BSA) and human serum albumins (HSA) were also studied using electronic absorption and fluorescence spectroscopic techniques and the results show that both complexes interact with the serum albumins via a ground state association process