Controle Local na era de responsabilidades: Um caso de estudo de pré-escola infantil (preK) em Wisconsin

The opposing principles of local control and increased standardization are a prominent tension in the United States’ education system. Since at least the early 1990s, this tension has taken shape around the accountability movement, defined by educational reforms that hold schools, teachers, and students accountable for performance on new standards, assessments, and curricula. While many scholars have examined the manifestations of the current accountability movement, few have looked at this phenomenon within the growing public preK movement. Drawing from interviews with state policymakers and district-level actors, this paper describes how the seemingly contradictory principles of local control and increased state and national standards (what we refer to simply as standardization) are shaping the policy and practice of Wisconsin’s preK system, known as 4K. We argue that rational models of policy making fail to explain the coexistence and blending of the strands of local control and standardization we found in our data, and suggest that Deborah Stone’s (2001) policy paradox provides a better theoretical framework for our findings.Los principios opuestos al control local y el aumentado de exámenes estandarizados han causado bastante tensión en el sistema de educación en los Estados Unidos. Desde el inicio del 1990, esta tensión ha tomado forma alrededor del movimiento de responsabilidad, que se distingue por las reformas educativas que tratan de asumir la responsabilidad a las escuelas, los profesores y estudiantes sobre las nuevas normas, evaluaciones y planes de estudio. Mientras muchos han examinado las manifestaciones del movimiento de la responsabilidad actual, pocos han observado este fenómeno que va creciendo dentro del movimiento preescolar (preK). Usando entrevistas con diseñadores de políticas de estado y autores a nivel del distrito, en este artículo se describe cómo aparentemente se contradicen los principios de control local y se aumentan las pólices estándares, nacionales y estatales (las que nos referimos simplemente como la estandarización) son mol-da la política y la práctica del sistema de pre-escolar (preK) de Wisconsin, conocido como "4K". Nuestro argumento es que los modelos racionales de la formulación de políticas fallan al explicar la convivencia y la mezcla de aspectos de control local y la paradoja política que encontramos en nuestros datos, sugieren que la política de Deborah Stone (2011) proporciona una mejor estructura teórico para nuestras recomendaciones.Os princípios opostos de controle local e o aumento na padronização são uma tensão proeminente no sistema de ensino dos Estados Unidos. Pelo menos desde o início dos anos 1990, essa tensão tem tomado forma em torno do movimento de responsabilidade, definido por reformas educacionais que sustentam escolas, professores, e estudantes responsáveis pelo desempenho de novos padrões, avaliações e currículos. Enquanto muitos estudiosos têm examinado as manifestações do atual movimento de responsabilização, poucos têm olhado para esse fenômeno dentro do crescimento público do movimento pré-escolar infantil (preK). Tomando de entrevistas com formuladores de políticas estatais e autores de nível distrital, este artigo descreve como princípios aparentemente contraditórios de controle local e o aumento de padrões nacionais e estatais (o que nos referimos simplesmente como padronização) estão moldando a política e a prática do sistema de pré-escola infantil (preK) de Wisconsin, conhecido como “4K”. Defendemos que os modelos racionais de formulação de políticas falham em explicar a coexistência e mistura dos fios de controle local e padronização que encontramos em nossos dados, e sugerem que o paradoxo da política de Deborah Stone (2011) proporciona uma melhor estrutura teórica para as nossas descobertas

The Herbertsmithite Hamiltonian: μ\muSR measurements on single crystals

We present transverse field muon spin rotation/relaxation measurements on single crystals of the spin-1/2 kagome antiferromagnet Herbertsmithite. We find that the spins are more easily polarized when the field is perpendicular to the kagome plane. We demonstrate that the difference in magnetization between the different directions cannot be accounted for by Dzyaloshinksii-Moriya type interactions alone, and that anisotropic axial interaction is present.Comment: 8 pages, 3 figures, accepted to JPCM special issue on geometrically frustrated magnetis

Kondo physics in the algebraic spin liquid

We study Kondo physics in the algebraic spin liquid, recently proposed to describe $ZnCu_{3}(OH)_{6}Cl_{2}$ [Phys. Rev. Lett. {\bf 98}, 117205 (2007)]. Although spin dynamics of the algebraic spin liquid is described by massless Dirac fermions, this problem differs from the Pseudogap Kondo model, because the bulk physics in the algebraic spin liquid is governed by an interacting fixed point where well-defined quasiparticle excitations are not allowed. Considering an effective bulk model characterized by an anomalous critical exponent, we derive an effective impurity action in the slave-boson context. Performing the large-$N_{\sigma}$ analysis with a spin index $N_{\sigma}$, we find an impurity quantum phase transition from a decoupled local-moment state to a Kondo-screened phase. We evaluate the impurity spin susceptibility and specific heat coefficient at zero temperature, and find that such responses follow power-law dependencies due to the anomalous exponent of the algebraic spin liquid. Our main finding is that the Wilson's ratio for the magnetic impurity depends strongly on the critical exponent in the zero temperature limit. We propose that the Wilson's ratio for the magnetic impurity may be one possible probe to reveal criticality of the bulk system

Recent Advances in Understanding Particle Acceleration Processes in Solar Flares

We review basic theoretical concepts in particle acceleration, with particular emphasis on processes likely to occur in regions of magnetic reconnection. Several new developments are discussed, including detailed studies of reconnection in three-dimensional magnetic field configurations (e.g., current sheets, collapsing traps, separatrix regions) and stochastic acceleration in a turbulent environment. Fluid, test-particle, and particle-in-cell approaches are used and results compared. While these studies show considerable promise in accounting for the various observational manifestations of solar flares, they are limited by a number of factors, mostly relating to available computational power. Not the least of these issues is the need to explicitly incorporate the electrodynamic feedback of the accelerated particles themselves on the environment in which they are accelerated. A brief prognosis for future advancement is offered.Comment: This is a chapter in a monograph on the physics of solar flares, inspired by RHESSI observations. The individual articles are to appear in Space Science Reviews (2011

First narrow-band search for continuous gravitational waves from known pulsars in advanced detector data

Spinning neutron stars asymmetric with respect to their rotation axis are potential sources of continuous gravitational waves for ground-based interferometric detectors. In the case of known pulsars a fully coherent search, based on matched filtering, which uses the position and rotational parameters obtained from electromagnetic observations, can be carried out. Matched filtering maximizes the signalto- noise (SNR) ratio, but a large sensitivity loss is expected in case of even a very small mismatch between the assumed and the true signal parameters. For this reason, narrow-band analysis methods have been developed, allowing a fully coherent search for gravitational waves from known pulsars over a fraction of a hertz and several spin-down values. In this paper we describe a narrow-band search of 11 pulsars using data from Advanced LIGO’s first observing run. Although we have found several initial outliers, further studies show no significant evidence for the presence of a gravitational wave signal. Finally, we have placed upper limits on the signal strain amplitude lower than the spin-down limit for 5 of the 11 targets over the bands searched; in the case of J1813-1749 the spin-down limit has been beaten for the first time. For an additional 3 targets, the median upper limit across the search bands is below the spin-down limit. This is the most sensitive narrow-band search for continuous gravitational waves carried out so far

A Standard Siren Measurement of the Hubble Constant from GW170817 without the Electromagnetic Counterpart

We perform a statistical standard siren analysis of GW170817. Our analysis does not utilize knowledge of NGC 4993 as the unique host galaxy of the optical counterpart to GW170817. Instead, we consider each galaxy within the GW170817 localization region as a potential host; combining the redshifts from all of the galaxies with the distance estimate from GW170817 provides an estimate of the Hubble constant, H 0. Considering all galaxies brighter than $0.626{L}_{B}^{\star }$ as equally likely to host a binary neutron star merger, we find ${H}_{0}={77}_{-18}^{+37}$ km s−1 Mpc−1 (maximum a posteriori and 68.3% highest density posterior interval; assuming a flat H 0 prior in the range $\left[10,220\right]$ km s−1 Mpc−1). We explore the dependence of our results on the thresholds by which galaxies are included in our sample, and we show that weighting the host galaxies by stellar mass or star formation rate provides entirely consistent results with potentially tighter constraints. By applying the method to simulated gravitational-wave events and a realistic galaxy catalog we show that, because of the small localization volume, this statistical standard siren analysis of GW170817 provides an unusually informative (top 10%) constraint. Under optimistic assumptions for galaxy completeness and redshift uncertainty, we find that dark binary neutron star measurements of H 0 will converge as $40 \% /\sqrt{(N)}$, where N is the number of sources. While these statistical estimates are inferior to the value from the counterpart standard siren measurement utilizing NGC 4993 as the unique host, ${H}_{0}={76}_{-13}^{+19}$ km s−1 Mpc−1 (determined from the same publicly available data), our analysis is a proof-of-principle demonstration of the statistical approach first proposed by Bernard Schutz over 30 yr ago

Increasing the Astrophysical Reach of the Advanced Virgo Detector via the Application of Squeezed Vacuum States of Light

Current interferometric gravitational-wave detectors are limited by quantum noise over a wide range of their measurement bandwidth. One method to overcome the quantum limit is the injection of squeezed vacuum states of light into the interferometer’s dark port. Here, we report on the successful application of this quantum technology to improve the shot noise limited sensitivity of the Advanced Virgo gravitational-wave detector. A sensitivity enhancement of up to 3.2±0.1  dB beyond the shot noise limit is achieved. This nonclassical improvement corresponds to a 5%–8% increase of the binary neutron star horizon. The squeezing injection was fully automated and over the first 5 months of the third joint LIGO-Virgo observation run O3 squeezing was applied for more than 99% of the science time. During this period several gravitational-wave candidates have been recorded

Quantum Backaction on kg-Scale Mirrors: Observation of Radiation Pressure Noise in the Advanced Virgo Detector

The quantum radiation pressure and the quantum shot noise in laser-interferometric gravitational wave detectors constitute a macroscopic manifestation of the Heisenberg inequality. If quantum shot noise can be easily observed, the observation of quantum radiation pressure noise has been elusive, so far, due to the technical noise competing with quantum effects. Here, we discuss the evidence of quantum radiation pressure noise in the Advanced Virgo gravitational wave detector. In our experiment, we inject squeezed vacuum states of light into the interferometer in order to manipulate the quantum backaction on the 42 kg mirrors and observe the corresponding quantum noise driven displacement at frequencies between 30 and 70 Hz. The experimental data, obtained in various interferometer configurations, is tested against the Advanced Virgo detector quantum noise model which confirmed the measured magnitude of quantum radiation pressure noise

Advanced Virgo Plus: Future Perspectives

While completing the commissioning phase to prepare the Virgo interferometer for the next joint Observation Run (O4), the Virgo collaboration is also finalizing the design of the next upgrades to the detector to be employed in the following Observation Run (O5). The major upgrade will concern decreasing the thermal noise limit, which will imply using very large test masses and increased laser beam size. But this will not be the only upgrade to be implemented in the break between the O4 and O5 observation runs to increase the Virgo detector strain sensitivity. The paper will cover the challenges linked to this upgrade and implications on the detector's reach and observational potential, reflecting the talk given at 12th Cosmic Ray International Seminar - CRIS 2022 held in September 2022 in Napoli