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Although SrNi$_2$P$_2$ adopts the common ThCr$_2$Si$_2$ structure for $T\geq 325$ K, being in an uncollapsed tetragonal state, on cooling below 325 K it adopts a one-third collapsed orthorhombic phase where one out of every three P rows bond across the Sr layers. On the other hand, SrCo$_2$P$_2$ only exhibits the uncollapsed ThCr$_2$Si$_2$ structure from room temperature down to 1.8 K. Neither SrNi$_2$P$_2$ nor SrCo$_2$P$_2$ manifests magnetic transitions down to 50 mK and 2 K, respectively. In this work we report the effects of Co substitution in Sr(Ni$_{1-x}$Co$_x$)$_2$P$_2$, which allows for tuning the transition between the one-third collapsed and the uncollapsed structure. We find a rapid decrease of the one-third collapsed structural transition temperature with increasing Co fraction, until reaching full suppression for $x \geq 0.1$. Substitution levels in the range $0.11\leq x\leq 0.58$ show no signs of any transition down to 1.8 K in the magnetization or resistance measurements in the range $1.8\ \text{K}\leq T\leq 300\ \text{K}$. However, different magnetically ordered states emerge for $x\geq 0.65$, and disappear for $x\geq 0.99$, recovering the known paramagnetic properties of the parent compound SrCo$_2$P$_2$. These results are summarized in a phase diagram, built upon the characterization done on single crystals with different Co fraction. Both the magnetic and structural properties are compared to other systems with ThCr$_2$Si$_2$ structure that exhibit magnetic ordering and collapsed tetragonal transitions. The magnetic ordering and moment formation are well described by Takahashi's spin fluctuation theory of itinerant electron magnetism., Comment: 17 pages, 20 figures

The maximum recoverable strain of most crystalline solids is less than 1% because plastic deformation or fracture usually occurs at a small strain. In this work, we show that a SrNi$_2$P$_2$ micropillar exhibits pseudoelasticity with a large maximum recoverable strain of ~14% under uniaxial compression via unique reversible structural transformation, double lattice collapse-expansion that is repeatable under cyclic loading. Its high yield strength (~3.8$\pm$0.5 GPa) and large maximum recoverable strain bring out the ultrahigh modulus of resilience (~146$\pm$19MJ/m$^3$) a few orders of magnitude higher than that of most engineering materials. The double lattice collapse-expansion mechanism shows stress-strain behaviors similar with that of conventional shape memory alloys, such as hysteresis and thermo-mechanical actuation, even though the structural changes involved are completely different. Our work suggests that the discovery of a new class of high performance ThCr$_2$Si$_2$-structured materials will open new research opportunities in the field of pseudoelasticity.

Low-dimensional organic conductors show a rich phase diagram, which has, despite all efforts, still some unexploed regions. Charge ordered phases present in many compounds of the (TMTTF)$_2 X$ family are typically studied with their unique electronic properties in mind. An influence on the spin arrangement is, however, not expected at first glance. Here, we report temperature and angle dependent electron spin resonance (ESR) measurements on the quasi one-dimensional organic conductor (TMTTF)$_2$NO$_3$. We found that the (TMTTF)$_2$NO$_3$ compound develops a peculiar anisotropy with a doubled periodicity ($ab'$-plane) of the ESR linewidth below about $T_\text{CO}=250\pm 10$ K. This behavior is similar to observations in the related compounds (TMTTF)$_2 X$ ($X$ = PF$_6$, SbF$_6$ and AsF$_6$), where it has been attributed to relaxation processes of magnetically inequivalent sites in the charge-ordered state. For the structural analogous (TMTTF)$_2$ClO$_4$, known for the absence of charge order, such angular dependence of the ESR signal is not observed. Therefore, our ESR measurements lead us to conclude that a charge-order phase is stabilized in the title compound below $T_\text{CO} \approx 250$ K.

The quasi-one-dimensional organic conductors (TMTTF)$_2X$ with non-centrosymmetric anions commonly undergo charge- and anion-order transitions upon cooling. While for compounds with tetrahedral anions ($X$ = BF$_4^-$, ReO$_4^-$, and ClO$_4^-$) the charge-ordered phase is rather well understood, the situation is less clear in the case of planar triangular anions, such as (TMTTF)$_2$NO$_3$. Here we explore the electronic and structural transitions by transport experiments, optical and magnetic spectroscopy. This way we analyze the temperature dependence of the charge imbalance 2$\delta$ and an activated behavior of $\rho(T)$ with $\Delta_{\rm CO}\approx 530$~K below $T_{\rm CO} = 250$~K. Since (TMTTF)$_2$NO$_3$ follows the universal relation between charge imbalance 2$\delta$ and size of the gap $\Delta_{\rm CO}$, our findings suggest that charge order is determined by TMTTF stacks with little influence of the anions. Clear signatures of anion ordering are detected at $T_{\rm AO}=50$~K. The tetramerization affects the dc transport, the vibrational features of donors and acceptors, and leads to formation of spin singlets.

This new edition of Successful School Leadership brings in the latest evidence and material to what has remained a popular publication. While the fundamentals of what drives successful school leadership remain the same, new evidence further supports the arguments put forward by Christopher Day and Pam Sammons back in 2016. The growing interest in system leadership that we have witnessed over the last five years also features in this edition, as does a reflection on the expanding body of international literature focused on school leadership in low-income contexts. The evidence examined by this review indicates that effective school leadership is important but, in isolation, is not a sufficient condition for successful school improvement. It shows that leadership has important effects on school organisation, culture and on teachers. Effects on student outcomes are largely indirect operating through direct effects on the organisation, culture and teaching and learning environment. The review draws particular attention to three concepts of leadership: transformational, pedagogical/instructional and distributed. While there is evidence that pedagogical/instructional leadership is important for promoting better academic outcomes for students, it is concluded that the three concepts of leadership are not mutually exclusive. It finds that most leadership effects operate indirectly to promote student outcomes by supporting and enhancing conditions for teaching and learning through direct impacts on teachers and their work, and that successful student outcomes are defined more broadly than academic performance alone (including attendance, behaviour, engagement and motivation, etc.). Moreover, single leadership strategies unrelated to educational purposes and national and local contexts are less likely to lead to success than combinations and accumulations of values-led and context-sensitive strategies which best illustrate the dynamic and complex nature of schools in the 21st century. Whether CEOs of multi-academy trusts, groups of schools, or principals of individual schools, school leaders have a key role to play in setting direction and creating and sustaining a positive school culture. This includes establishing a proactive, collaborative school mindset, supporting and enhancing staff, as well as student motivation, engagement and well-being, and the collective commitment needed to foster improvement and promote and sustain success for schools and classrooms which serve a range of advantaged and disadvantaged communities. [For the 2016 edition, see ED565740.]

Reliable neutron-induced reaction cross sections of unstable nuclei are essential for nuclear astrophysics and applications but their direct measurement is often impossible. The surrogate-reaction method is one of the most promising alternatives to access these cross sections. In this work, we successfully applied the surrogate-reaction method to infer for the first time both the neutron-induced fission and radiative-capture cross sections of 239Pu in a consistent manner from a single measurement. This was achieved by combining simultaneously-measured fission and gamma-emission probabilities for the 240Pu(4He,4He') surrogate reaction with a calculation of the angular-momentum and parity distributions populated in this reaction. While other experiments measure the probabilities for some selected gamma-ray transitions, we measure the gamma-emission probability. This enlarges the applicability of the surrogate-reaction method., Comment: 8 pages, 3 figures

Particle-$\gamma$ coincidence experiments were performed at the Oslo Cyclotron Laboratory with the $^{181}$Ta(d,X) and $^{181}$Ta($^{3}$He,X) reactions, to measure the nuclear level densities (NLDs) and $\gamma$-ray strength functions ($\gamma$SFs) of $^{180, 181, 182}$Ta using the Oslo method. The Back-shifted Fermi-Gas, Constant Temperature plus Fermi Gas, and Hartree-Fock-Bogoliubov plus Combinatorial models where used for the absolute normalisations of the experimental NLDs at the neutron separation energies. The NLDs and $\gamma$SFs are used to calculate the corresponding $^{181}$Ta(n,$\gamma$) cross sections and these are compared to results from other techniques. The energy region of the scissors resonance strength is investigated and from the data and comparison to prior work it is concluded that the scissors strength splits into two distinct parts. This splitting may allow for the determination of triaxiality and a $\gamma$ deformation of $14.9^{\circ} \pm 1.8^{\circ}$ was determined for $^{181}$Ta.

This panel examines research on early education from two research practice partnerships, the Baltimore Education Research Consortium (BERC) with Baltimore City Schools and Johns Hopkins University in Baltimore, Maryland, and the Stanford-SFUSD Partnership with San Francisco Unified School District (SFUSD) and Stanford University in San Francisco, California. First, it explores how BERC convened the Early Education Data Collaborative (EEDC), a collection of Baltimore agencies that provide services to children from birth through the early elementary years whose goal is to understand how different pathways to kindergarten may be associated with kindergarten readiness and later learning outcomes. Second, it explores a line of research by a Stanford University professor and her team of doctoral students working with SFUSD's early education department. The Stanford team worked with SFUSD to establish and test a new Pre-Kindergarten (Pre-K) early literacy assessment aligned to K-12 measures, and also established a kindergarten readiness indicator that has been used by SFUSD over the past three years. The Baltimore sample included 11,897 kindergarten students across two cohorts with matched program and birth records. The San Francisco Transitional Kindergarten study examines literacy outcomes, as measured by the Fountas and Pinnell Benchmark Assessment System, of Kindergarteners enrolled in SFUSD in the 2013-2014 and 2014-2015 school years. The sample contains 6,174 students, 5% of which (309 students) had enrolled in the TK program. Another 17% (1,051 students) attended the district's Pre-K program. The remainder of the students had the option to attend a Pre-K program offered by San Francisco. Both studies examine the use of longitudinal data sets from large urban school districts with robust early education programs. The Baltimore study provides an analysis comparing kindergarten readiness measures for the three most common pathways to kindergarten: Baltimore City Schools Pre-K, Baltimore City Head Start, and both programs. Preliminary results from the first cohort of students from the Baltimore study show when the mother's background and the circumstances of the child's birth are accounted for (Model 2), students with prior experience in only Head Start are more likely to be ready for kindergarten than students who did not attend either program (odds ratio: 1.260; 95% CI: 1.016, 1.563). When the mother's background and the circumstances of the child's birth are accounted for (Model 2), children who attended both Head Start and BCPS Pre-K are nearly four times as likely to be identified as ready for kindergarten as children from neither program (odds ratio: 3.904; 95% CI: 3.058, 4.983). Children who attended only BCPS Pre-K were three times as likely to be ready for kindergarten than children who attended neither program (odds ratio: 3.314; 95% CI: 2.744, 4.009) when family background is taken into account. Preliminary results from the SFUSD Transitional Kindergarten (TK) study indicate that the program may have increased fall student literacy outcomes. Fall results, however, indicate that TK students are not more likely to be able to read books. Four data tables are appended.

Isospin properties of dipole excitations in 74 Ge are investigated using the ({\alpha},{\alpha}'{\gamma}) reaction and compared to ({\gamma},{\gamma}) data. The results indicate that the dipole excitations in the energy region of 6 to 9 MeV adhere to the scenario of the recently found splitting of the region of dipole excitations into two separated parts: one at low energy, being populated by both isoscalar and isovector probes, and the other at high energy, excited only by the electromagnetic probe. Relativistic quasiparticle time blocking approximation (RQTBA) calculations show a reduction in the isoscalar E1 strength with an increase in excitation energy, which is consistent with the measurement., Comment: 7 pages, 7 figures

We present considerations about the transverse beam transfer function (BTF) of beams under the influence of two effects: The strong-strong beam-beam effect and the influence of a Gaussian electron lens. The BTF are investigated using two methods: BTF excitation is simulated in a particle-in-cell (PIC) code. The BTF model is verified using a known analytic expectation. Analytic expectations for BTF of beams under a stationary electron lens are derived by extending BTF from the formalism of Berg and Ruggiero. Finally we compare the analytic BTF results for a stationary Gaussian lens to both the PIC simulation for split tune conditions and to PIC simulations for a beam influenced by an electron lens. We conclude that the formalism represents the electron lens well and can be applied to a limited extend to the beam-beam effect under split tune conditions. The analytic formalism allows us to recover the strength of an electron lens by means of fitting and can give clues regarding the strength of the beam-beam effect under split tune conditions., Comment: 5 pages, contribution to the ICFA Mini-Workshop on Beam-Beam Effects in Hadron Colliders, CERN, Geneva, Switzerland, 18-22 Mar 2013

New positive-parity states, having a band-like structure, were observed in 105Ru. The nucleus was produced in induced fission reaction and the prompt gamma-rays, emitted from the fragments, were detected by the EUROBALL III multi-detector array. The partial scheme of excited 105Ru levels is analyzed within the Triaxial-Rotor-plus-Particle approach.

Spectra of outgoing neutrons and protons from the 6Li+55Mn reaction and protons from the a+57Fe reaction have been measured with beams of 15 MeV 6Li ions and 30 MeV alpha-particles. These reactions proceed through the same 61Ni nucleus at the same excitation energy, thus allowing the difference in reaction mechanism to be studied. It is shown that spectra from the first reaction measured at backward angles are due to emission from a traditional compound nucleus reaction, in which the intermediate nucleus has reached statistical equilibrium; the spectra from the second reaction contain a significant fraction of pre-equilibrium emission at all angles. Level density pa- rameters of the residual nucleus 60Co have been obtained from the first reaction. Both emission spectra and angular distributions have been measured for the second reaction. It was found that the pre-equilibrium component exhibits a forward-peaked angular distribution, as expected, but with a steeper slope than predicted and with an unusual slight rise at angles above 120\deg. The backward- angle rise is explained qualitatively by the dominance of the multi-step compound mechanism at backward angles.