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The fourth-grade 2019 National Assessment of Educational Progress (NAEP) Reading assessment shows that 34% of the nation’s students perform below the NAEP Basic level. However, because there is no achievement-level description for below Basic, educators and policymakers lack information on the nature of the reading difficulties that these students face. To help fill this gap, we analyze data from the 2018 NAEP Oral Reading Fluency study. We find that, compared with students who perform at the NAEP Basic level and above, students who perform below NAEP Basic level are much more likely to have poor oral reading fluency and word reading skills.

Wave packet molecular dynamics (WPMD) has recently received a lot of attention as a computationally fast tool with which to study dynamical processes in warm dense matter beyond the Born–Oppenheimer approximation. These techniques, typically, employ many approximations to achieve computational efficiency while implementing semi-empirical scaling parameters to retain accuracy. We investigated three of the main approximations ubiquitous to WPMD: a restricted basis set, approximations to exchange, and the lack of correlation. We examined each of these approximations in regard to atomic and molecular hydrogen in addition to a dense hydrogen plasma. We found that the biggest improvement to WPMD comes from combining a two-Gaussian basis with a semi-empirical correction based on the valence-bond wave function. A single parameter scales this correction to match experimental pressures of dense hydrogen. Ultimately, we found that semi-empirical scaling parameters are necessary to correct for the main approximations in WPMD. However, reducing the scaling parameters for more ab-initio terms gives more accurate results and displays the underlying physics more readily.

The structural evolution of laser-excited systems of gold has previously been measured through ultrafast MeV electron diffraction. 1 - 3 However, there has been a long-standing inability of atomistic simulations to provide a consistent picture of the melt process, concluding in large discrepancies between the predicted threshold energy density for complete melt, as well as the transition between heterogeneous and homogeneous melting. 1 We make use of two-temperature classical molecular dynamics simulations utilizing two highly successful interatomic potentials and reproduce electron diffraction data presented by Mo et al.. We recreate the experimental electron diffraction data employing both a constant and temperature-dependent electron-ion equilibration rate. In all cases we are able to match time-resolved electron diffraction data, and find consistency between atomistic simulations and experiments, only by allowing laser energy to be transported away from the interaction region for the duration of the melt process. This additional energy-loss pathway, which scales strongly with laser fluence, we attribute to hot electrons leaving the target during melt before refluxing.

X-ray phase-contrast imaging of micron-scale objects and features requires high spatial coherence. These highly spatially coherent x-rays can be generated at fourth generation light sources or by passing laser-produced x-rays through a narrow slit. By coupling these sources to an isochoric heating platform, we can measure the dynamic changes in density gradients at the interface between two warm dense matter (WDM) samples with micron-scale spatial resolution. The high spatial coherence gives rise to refractive and diffractive features at the interface 1 , 2 , 3 , allowing for precise measurement of dynamic processes in WDM, including transport properties and measuring the equation of state. We will present an overview of successful experiments at both the Omega Laser Facility and the European XFEL that demonstrate our platform's high efficacy and spatial resolution for characterizing density gradients in dynamically evolving WDM systems.

We present an overview of the development of our Fresnel Refractive Diffractive Radiography (FDR) platform for the Extreme Light Laboratory (ELL) at the University of Nebraska–Lincoln. This platform couples isochorically heated buried wires with dynamic X-ray phase-contrast imaging of the warm dense matter (WDM) samples 1 . By utilizing novel 1 µm-wide slits, we obtain a highly spatially coherent x-ray source that gives rise to significant refractive and diffractive features from micron-scale density gradients at the interface 2 . Measurement of the evolution of this density profile, driven primarily by the equation of state and thermal conductivity, opens the door for direct measurements of transport properties in WDM 3 . By utilizing a copper tape drive and novel wire extruder we create replenishing solid targets that allow for significantly higher repetition rates than previously demonstrated.

Review of scientific instruments 92(3), 039901 (2021). doi:10.1063/5.0043951, This article was originally published online on 4 January 2021 with an error in the title and Ref. 6 should have been deleted from the reference section and the text. The title is correct above. All online and printed versions of the article were corrected on 7 January 2021. AIP Publishing apologizes for this error., Published by American Institute of Physics, [S.l.]

We present on the design, use, and alignment procedure of novel 1 µm-wide slits for use in x-ray diffractive radiography of warm dense matter at the Omega Laser Facility at the Laboratory for Laser Energetics.

Review of scientific instruments 92(1), 013101 (2021). doi:10.1063/5.0022886, We introduce a setup to measure high-resolution inelastic x-ray scattering at the High Energy Density scientific instrument at the European X-Ray Free-Electron Laser (XFEL). The setup uses the Si (533) reflection in a channel-cut monochromator and three spherical diced analyzer crystals in near-backscattering geometry to reach a high spectral resolution. An energy resolution of 44 meV is demonstrated for the experimental setup, close to the theoretically achievable minimum resolution. The analyzer crystals and detector are mounted on a curved-rail system, allowing quick and reliable changes in scattering angle without breaking vacuum. The entire setup is designed for operation at 10 Hz, the same repetition rate as the high-power lasers available at the instrument and the fundamental repetition rate of the European XFEL. Among other measurements, it is envisioned that this setup will allow studies of the dynamics of highly transient laser generated states of matter., Published by American Institute of Physics, [S.l.]

Scientific reports 10(1), 14564 (2020). doi:10.1038/s41598-020-71350-x, Published by Macmillan Publishers Limited, part of Springer Nature, [London]

We perform nonadiabatic simulations of warm dense aluminum based on the electron-force field (EFF) variant of wave-packet molecular dynamics. Comparison of the static ion-ion structure factor with density functional theory (DFT) is used to validate the technique across a range of temperatures and densities spanning the warm dense matter regime. Focusing on a specific temperature and density (3.5 eV, 5.2 g/cm3), we report on differences in the dynamic structure factor and dispersion relation across a variety of adiabatic and nonadiabatic techniques. We find the dispersion relation produced with EFF is in close agreement with the more robust and adiabatic Kohn-Sham DFT., Comment: 7 pages and 5 figures in the main manuscript; typos corrected; final version of publication

Understanding magnetic-field generation and amplification in turbulent plasma is essential to account for observations of magnetic fields in the universe. A theoretical framework attributing the origin and sustainment of these fields to the so-called fluctuation dynamo was recently validated by experiments on laser facilities in low-magnetic-Prandtl-number plasmas ($\mathrm{Pm} < 1$). However, the same framework proposes that the fluctuation dynamo should operate differently when $\mathrm{Pm} \gtrsim 1$, the regime relevant to many astrophysical environments such as the intracluster medium of galaxy clusters. This paper reports a new experiment that creates a laboratory $\mathrm{Pm} \gtrsim 1$ plasma dynamo for the first time. We provide a time-resolved characterization of the plasma's evolution, measuring temperatures, densities, flow velocities and magnetic fields, which allows us to explore various stages of the fluctuation dynamo's operation. The magnetic energy in structures with characteristic scales close to the driving scale of the stochastic motions is found to increase by almost three orders of magnitude from its initial value and saturate dynamically. It is shown that the growth of these fields occurs exponentially at a rate that is much greater than the turnover rate of the driving-scale stochastic motions. Our results point to the possibility that plasma turbulence produced by strong shear can generate fields more efficiently at the driving scale than anticipated by idealized MHD simulations of the nonhelical fluctuation dynamo; this finding could help explain the large-scale fields inferred from observations of astrophysical systems., 12 pages, 9 figures

We develop a new approach to modeling many-body systems based on Bohm’s interpretation of quantum mechanics., Modeling many-body quantum systems with strong interactions is one of the core challenges of modern physics. A range of methods has been developed to approach this task, each with its own idiosyncrasies, approximations, and realm of applicability. However, there remain many problems that are intractable for existing methods. In particular, many approaches face a huge computational barrier when modeling large numbers of coupled electrons and ions at finite temperature. Here, we address this shortfall with a new approach to modeling many-body quantum systems. On the basis of the Bohmian trajectory formalism, our new method treats the full particle dynamics with a considerable increase in computational speed. As a result, we are able to perform large-scale simulations of coupled electron-ion systems without using the adiabatic Born-Oppenheimer approximation.

The properties of supersonic, compressible plasma turbulence determine the behavior of many terrestrial and astrophysical systems. In the interstellar medium and molecular clouds, compressible turbulence plays a vital role in star formation and the evolution of our galaxy. Observations of the density and velocity power spectra in the Orion B and Perseus molecular clouds show large deviations from those predicted for incompressible turbulence. Hydrodynamic simulations attribute this to the high Mach number in the interstellar medium (ISM), although the exact details of this dependence are not well understood. Here we investigate experimentally the statistical behavior of boundary-free supersonic turbulence created by the collision of two laser-driven high-velocity turbulent plasma jets. The Mach number dependence of the slopes of the density and velocity power spectra agree with astrophysical observations, and supports the notion that the turbulence transitions from being Kolmogorov-like at low Mach number to being more Burgers-like at higher Mach numbers., Supersonic turbulence is relevant to astrophysical plasmas with their study mostly limited to numerical simulations. Here the authors demonstrate supersonic turbulence in collisional high Mach number plasma jets generated in laboratory by using high power lasers.

Identifying the sources of the highest energy cosmic rays requires understanding how they are deflected by the stochastic, spatially intermittent intergalactic magnetic field. Here we report measurements of energetic charged-particle propagation through a laser-produced magnetized plasma with these properties. We characterize the diffusive transport of the particles experimentally. The results show that the transport is diffusive and that, for the regime of interest for the highest-energy cosmic rays, the diffusion coefficient is unaffected by the spatial intermittency of the magnetic field., Comment: Updated Author and Reviewer Information, 23 pages 17 figures

Magnetic fields are ubiquitous in the Universe. The energy density of these fields is typically comparable to the energy density of the fluid motions of the plasma in which they are embedded, making magnetic fields essential players in the dynamics of the luminous matter. The standard theoretical model for the origin of these strong magnetic fields is through the amplification of tiny seed fields via turbulent dynamo to the level consistent with current observations. However, experimental demonstration of the turbulent dynamo mechanism has remained elusive, since it requires plasma conditions that are extremely hard to re-create in terrestrial laboratories. Here we demonstrate, using laser-produced colliding plasma flows, that turbulence is indeed capable of rapidly amplifying seed fields to near equipartition with the turbulent fluid motions. These results support the notion that turbulent dynamo is a viable mechanism responsible for the observed present-day magnetization., Seventh Framework Programme (European Commission) (Grant 256973), Seventh Framework Programme (European Commission) (Grant 247039), United States. Department of Energy (Lawrence Livermore National Laboratory. Contract B591485), United States. Department of Energy (Grant DE-NA0003539)

Magnetic field measurements in turbulent plasmas are often difficult to perform. Here we show that for ${\geqslant}$kG magnetic fields, a time-resolved Faraday rotation measurement can be made at the OMEGA laser facility. This diagnostic has been implemented using the Thomson scattering probe beam and the resultant path-integrated magnetic field has been compared with that of proton radiography. Accurate measurement of magnetic fields is essential for satisfying the scientific goals of many current laser–plasma experiments.

International audience; We describe a setup for performing inelastic X-ray scattering and X-ray diffraction measurements at the Matter in Extreme Conditions (MEC) endstation of the Linac Coherent Light Source. This technique is capable of performing high-, meV-resolution measurements of dynamic ion features in both crystalline and non-crystalline materials. A four-bounce silicon (533) monochromator was used in conjunction with three silicon (533) diced crystal analyzers to provide an energy resolution of ∼50 meV over a range of ∼500 meV in single shot measurements. In addition to the instrument resolution function, we demonstrate the measurement of longitudinal acoustic phonon modes in polycrystalline diamond. Furthermore, this setup may be combined with the high intensity laser drivers available at MEC to create warm dense matter and subsequently measure ion acoustic modes.

Betatron radiation from laser wakefield accelerators is an ultrashort pulsed source of hard, synchrotron-like x-ray radiation. It emanates from a centimetre scale plasma accelerator producing GeV level electron beams. In recent years betatron radiation has been developed as a unique source capable of producing high resolution x-ray images in compact geometries. However, until now, the short pulse nature of this radiation has not been exploited. This report details the first experiment to utilise betatron radiation to image a rapidly evolving phenomenon by using it to radiograph a laser driven shock wave in a silicon target. The spatial resolution of the image is comparable to what has been achieved in similar experiments at conventional synchrotron light sources. The intrinsic temporal resolution of betatron radiation is below 100 fs, indicating that significantly faster processes could be probed in future without compromising spatial resolution. Quantitative measurements of the shock velocity and material density were made from the radiographs recorded during shock compression and were consistent with the established shock response of silicon, as determined with traditional velocimetry approaches. This suggests that future compact betatron imaging beamlines could be useful in the imaging and diagnosis of high-energy-density physics experiments., 11 pages, 7 figures

lthough the overall function of a campaign’s primary target design may remain unchanged, the components and structure often evolve from one shot day to the next to better meet experimental goals. The target fabrication engineer’s involvement in this evolution can be important for advising modifications in order to improve and simplify assembly at the same time. Highly complex targets are constructed by General Atomics (GA) for astrophysics experiments conducted by the University of Chicago at the OMEGA laser facility. Several novel target components are fabricated, precision-assembled, and extensively measured in support of this campaign, and have evolved over the last three years to improve both the science and assembly. Examples include unique laser machined polyimide grids to enhance plasma mixing at target center, precision micromachined cylindrical shields that also act as component spacers, drawn glass target supports to suspend physics packages at critical distances, and tilted pinholes for collimated proton radiography. Target component fabrication and evolution details for this turbulent dynamics (TDYNO) campaign are presented, along with precision-assembly techniques, metrology methods, and considerations for future TDYNO experiments on OMEGA.

A randomized trial involving 19 elementary schools (K–5) was conducted to replicate and extend two previous experimental studies of the effects of a voluntary summer reading program that provided (a) books matched to students' reading levels and interests and (b) teacher scaffolding in the form of end-of-year comprehension lessons. Matched schools were randomly assigned to implement one of two lesson types. Within schools, students were randomly assigned to a control condition or one of two treatment conditions: a basic treatment condition replicating procedures used in the previous studies or an enhanced treatment condition that added teacher calls in the summer. During summer vacation, students in the treatment conditions received two lesson books and eight books matched to their reading level and interests. Overall, there were no significant treatment effects, and treatment effects did not differ across lesson type. However, there was a significant interaction between the treatment conditions and poverty measured at the school level. The effects of the treatments were positive for high-poverty schools (Cohen's d = .08 and .11, respectively), defined as schools where 75–100% of the students were receiving free or reduced-price lunch (FRL). For moderate-poverty schools (45–74% FRL), the effects of the treatments were negative (Cohen's d = −.11 and −.12, respectively). The results underscore the importance of looking at patterns of treatment effects across different contexts, settings, and populations. 研究者在19所美国小学(幼儿园至小学五年级)中进行一项随机研究试验,以复制和扩展先前两项暑期自愿阅读计划效应的实验研究;该阅读计划提供给学校(1)切合学生阅读水平和兴趣的读本和(2)年终阅读理解课程形式的教师支援。匹配的学校被随机分配并实施两种授课类型的其中一种。在每所校内,学生被随机分配到控制组或干预组,而干预组有两个:基本干预组(复制先前研究的干预程序)和强化干预组(附加教师在暑期到访的干预程序)。在暑假期间,干预组的学生获派发两本教学课本和八本切合他们阅读水平和兴趣的书籍。总的来说,研究结果显示干预效应并不显著,而且两种授课类型的干预效果之间亦没有差异。然而,干预效果与学校贫困程度之间,却产生显著的相互作用。干预效果对于高贫困的学校是正面的(效应值分别为.08 和.11),高贫困学校的界定为校内有75%或以上的学生正在领取免费或减价午餐(简称为 FRL)的学校。对于中度贫困的学校(有45-74%FRL学生)而言,干预效果是负面的(效应值分别为−.11和−.12)。本研究的结果强调在考查横跨不同的环境、设置和研究对象总体的情况时,检视干预效果样式的重要性。 Se hizo una prueba al azar de 19 escuelas primarias (K–5) para replicar y ampliar dos estudios experimentales anteriores de los efectos de un programa de lectura voluntaria durante el verano que proporciono (a) libros que concordaban con los intereses y el nivel de lectura de los estudiantes y (b) el apoyo de los maestros en terminos de lecciones de comprension de final del ano. Se combinaron las escuelas y se les dio, al azar, uno de dos tipos de lecciones para que lo implementaran. Dentro de las escuelas, se les asignaron, al azar, a los estudiantes la condicion de control o una de dos condiciones de tratamiento: una condicion de tratamiento basica que replicaba los procedimientos usados en el estudio anterior o una condicion de tratamiento mejorada que anadia llamadas hechas por los maestros durante el verano. Durante las vacaciones de verano, los estudiantes en las condiciones de tratamientos recibieron dos libros de lecciones y ocho libros que correspondian a sus intereses y nivel de lectura. En total, no hubo efectos importantes de tratamiento, y los efectos del tratamiento de eran diferentes a traves de los tipos de lecciones. Sin embargo, se encontro una interaccion importante entre las condiciones de tratamiento y la pobreza medida a nivel de la escuela. El efecto de los tratamientos fueron positivos en las escuelas de algo grado de pobreza (segun Cohen, respectivamente, d = .08 y .11), las cuales fueron definidas como escuelas donde del 75 al 100% de los estudiantes recibian almuerzo gratis o subsidiado (FRL por sus siglas en ingles). Para escuelas con un grado moderado de pobreza (45–74% FRL) los efectos de los tratamientos fue negativo (segun Cohen respectivamente, d = 1.11 y 1.12). Los resultados muestran la importancia de tomar en cuenta los patrones de efectos de tratamientos a traves de diferentes contextos, ambientes y poblaciones. لقد أجريت تجربة ذات الاختيار العشوائي شملت 19 مدرسة ابتدائية (من الروضة حتى الصف الخامس) ليقلد ويمدد تجربتين سابقتين ذات الاختيار العشوائي وكذلك فحصت تأثيرات برنامج القراءة الصيفي الطوعي الذي وفر (أ) كتبا تناسب مستوى الطالب القرائي واهتماماته و(ب) سقالة المعلم التي تأخذ شكل دروس الاستيعاب في نهاية العام الدراسي. وقد تحدد بعض المدارس لتنفيذ نوع من نوعي الدرس. وفي تلك المدارس، تحدد الطلاب عشوائيا لظرف ضابط أو لظرف من ظرفي العلاج: ظرف علاج أساسي يقلد الإجراءات المستخدمة في الدراسات السابقة أو ظرف علاج متعزز وقد تمت الإضافة إليها مكالمات المعلمين أثناء فصل الصيف. أما أثناء إجازة الصيف، فالطلاب في ظروف العلاج استلموا مقررين وثمانية كتب تتلاءم مع مستواهم القرائي واهتماماتهم. وعموما لم يكن ثمة تأثيرات علاج هامة، ولم تختلف تأثيرات العلاج عبر نوع الدرس. وبالرغم من هذا، كان ثمة ارتباط هام بين ظروف العلاج والفقر ينقاس على مستوى المدرسة. وكانت تأثيرات العلاج إيجابية للمدارس ذات الفقر الشديد (حجم التأثير د = 08، و11، على التوالي) وهذا يعرف كالمدارس حيث 75-100% من الطلاب كانوا يستلمون غداءهم بالمجان أو بأسعار منخفضة جدا. وبالنسبة إلى المدارس ذات الفقر المعتدل (45-74% للغداء المجان أو أسعاره منخفضة) كانت تأثيرات العلاج سلبية (حجم التأثير د = 11،- و12،- على التوالي). تؤكد النتائج أهمية النظر إلى أنماط تأثيرات العلاج عبر فروق في السياقات والمواقف والتجمعات السكانية. Paндoмизиpoвaннoe иccлeдoвaниe, пpoвeдeннoe в 19 нaчaльныx шкoлax (c 1 пo 5 клacc), былo пpизвaнo вocпpoизвecти и pacшиpить двa пpeдыдyщиx экcпepимeнтaльныx иccлeдoвaния peзyльтaтoв дoбpoвoльнoй пpoгpaммы лeтнeгo чтeния, в кoтopoй: (a) книги пoдбиpaлиcь пo ypoвню читaтeльcкиx нaвыкoв и интepecaм yчaщиxcя, (б) yчитeль в кoнцe yчeбнoгo гoдa пpoвoдил пoдгoтoвитeльныe зaнятия для лyчшeгo пoнимaния тeкcтoв. Шкoлaм-yчacтницaм экcпepимeнтa былo пpeдлoжeнo – пo cлyчaйнoмy пpинципy – ocyщecтвить oдин из двyx пpeдлoжeнныx пoдxoдoв. B caмиx шкoлax yчaщиxcя, oпять жe пo cлyчaйнoмy пpинципy, oпpeдeлили либo в кoнтpoльнyю гpyппy, либo в oднy из двyx экcпepимeнтaльныx гpyпп: в пepвoй вocпpoизвoдилиcь пpoцeдypы, иcпoльзoвaвшиecя в пpeдыдyщиx иccлeдoвaнияx, вo втopoй пoмoщь дeтям былa pacшиpeнa в видe пoддepживaющиx звoнкoв yчитeля в лeтнee вpeмя. Ha лeтниe кaникyлы yчaщиecя из oбeиx экcпepимeнтaльныx гpyпп пoлyчили пo двa yчeбныx пocoбия и вoceмь книг, пoдoбpaнныx пo иx ypoвню чтeния и интepecaм. B цeлoм, ни в oднoй из гpyпп нe oтмeчeнo cyщecтвeннoй динaмики peзyльтaтoв. Oднaкo пpocлeживaeтcя cyщecтвeннaя зaвиcимocть мeждy peзyльтaтaми и ypoвнeм бeднocти ceмeй yчaщиxcя, xapaктepнoм для тoй или инoй шкoлы. Эффeктивнocть дoбpoвoльнoй пpoгpaммы чтeния oкaзaлacь вышe в шкoлax c выcoким ypoвнeм бeднocти: вeличинa эффeктa пo Дж.Кoэнy (d) = .08 и .11, в пepвoй и втopoй экcпepимeнтaльныx гpyппax cooтвeтcтвeннo. Кpитepий для пpичиcлeния шкoл к выcoкoмy ypoвню бeднocти: 75-100% yчaщиxcя пoлyчaют бecплaтнoe или льгoтнoe питaниe (FRL). Для шкoл yмepeннoй бeднocти, гдe FRL cocтaвляeт 45-74%, эффeктивнocть пpoгpaммы oкaзaлacь oтpицaтeльнa: d Кoэнa = −.11 и −.12, cooтвeтcтвeннo. Peзyльтaты пoдчepкивaют, чтo вaжнo paccмaтpивaть peзyльтaты любoй пpoгpaммы c yчeтoм кoнтeкcтa, ycлoвий и cocтaвa yчacтникoв. Un essai aleatoire impliquant 19 ecoles elementaires (du jardin d'enfants a la 5e annee elementaire) a ete realise afin de repliquer et d’etendre deux etudes experimentales precedentes portant sur les effets d'un programme libre de lecture d’ete offrant a) des livres adaptes aux niveaux et aux interets des eleves et b) un etayage du professeur sous forme de lecons de comprehension de fin d'annee. Des ecoles appariees ont ete choisies au hasard pour beneficier d'une des deux lecons-type. Dans les ecoles, les eleves ont ete assignes au hasard a l'une ou l'autre des conditions de controle suivantes : une condition de traitement de base repliquant les procedures utilisees dans les etudes anterieures ou une condition de traitement renforce constituee d'appels telephoniques au professeur pendant l’ete. Pendant les vacances d’ete, les eleves places dans les conditions experimentales ont recu deux livres de lecons et huit livres adaptes a leur niveau de lecture et a leurs interets. De facon generale, on n'observe pas d'effets significatifs des traitements experimentaux, et les effets des traitements ne varient pas selon la lecon-type. On note cependant une interaction significative entre les conditions de traitement et la pauvrete mesuree au niveau de l’ecole. Les effets des traitements sont positifs pour les ecoles tres pauvres (d de Cohen = .08 and .11, respectivement) definies comme les ecoles ou 75 a 100% des eleves ne paient pas la cantine ou ne la paient qu'en partie. Pour les ecoles moins pauvres (45 a 74% du prix de la cantine), les effets du traitement sont negatifs (d de Cohen= −.11 and −.12, respectivement). Ces resultats minimisent l'importance a accorder aux structures des effets des traitements qui prennent en compte les contextes, les situations et les populations.

We describe the capability of a high-resolution three-dimensional digital image correlation (DIC) system specifically designed for high strain-rate experiments. Utilising open-source camera calibration and two-dimensional DIC tools within the MATLAB framework, a single camera three-dimensional DIC system with submicron displacement resolution is demonstrated. The system has a displacement accuracy of up to 200 times the optical spatial resolution, matching that achievable with commercial systems. The surface strain calculations are benchmarked against commercially available software before being deployed on quasi-static tests showcasing the ability to detect both in- and out-of-plane motion. Finally, a high strain-rate (1.2$\times$10$^3$ s$^{-1}$) test was performed on a top-hat sample compressed in a split-Hopkinson pressure bar in order to highlight the inherent camera synchronisation and ability to resolve the adiabatic shear band phenomenon.

Recent laser-plasma experiments report the existence of dynamically significant magnetic fields, whose statistical characterisation is essential for understanding the physical processes these experiments are attempting to investigate. In this paper, we show how a proton imaging diagnostic can be used to determine a range of relevant magnetic field statistics, including the magnetic-energy spectrum. To achieve this goal, we explore the properties of an analytic relation between a stochastic magnetic field and the image-flux distribution created upon imaging that field. We conclude that features of the beam's final image-flux distribution often display a universal character determined by a single, field-scale dependent parameter - the contrast parameter - which quantifies the relative size of the correlation length of the stochastic field, proton displacements due to magnetic deflections, and the image magnification. For stochastic magnetic fields, we establish the existence of four contrast regimes - linear, nonlinear injective, caustic and diffusive - under which proton-flux images relate to their parent fields in a qualitatively distinct manner. As a consequence, it is demonstrated that in the linear or nonlinear injective regimes, the path-integrated magnetic field experienced by the beam can be extracted uniquely, as can the magnetic-energy spectrum under a further statistical assumption of isotropy. This is no longer the case in the caustic or diffusive regimes. We also discuss complications to the contrast-regime characterisation arising for inhomogeneous, multi-scale stochastic fields, as well as limitations currently placed by experimental capabilities on extracting magnetic field statistics. The results presented in this paper provide a comprehensive description of proton images of stochastic magnetic fields, with applications for improved analysis of given proton-flux images., Comment: Main paper pp. 1-29; appendices pp. 30-84. 24 figures, 2 tables

The universe is permeated by magnetic fields, with strengths ranging from a femtogauss in the voids between the filaments of galaxy clusters to several teragauss in black holes and neutron stars. The standard model behind cosmological magnetic fields is the nonlinear amplification of seed fields via turbulent dynamo to the values observed. We have conceived experiments that aim to demonstrate and study the turbulent dynamo mechanism in the laboratory. Here we describe the design of these experiments through simulation campaigns using FLASH, a highly capable radiation magnetohydrodynamics code that we have developed, and large-scale three-dimensional simulations on the Mira supercomputer at Argonne National Laboratory. The simulation results indicate that the experimental platform may be capable of reaching a turbulent plasma state and study dynamo amplification. We validate and compare our numerical results with a small subset of experimental data using synthetic diagnostics., Comment: Accepted for publication on Physics of Plasmas, 15 pages 12 figures

The state and evolution of planets, brown dwarfs and neutron star crusts is determined by the properties of dense and compressed matter. Due to the inherent difficulties in modelling strongly coupled plasmas, however, current predictions of transport coefficients differ by orders of magnitude. Collective modes are a prominent feature, whose spectra may serve as an important tool to validate theoretical predictions for dense matter. With recent advances in free electron laser technology, X-rays with small enough bandwidth have become available, allowing the investigation of the low-frequency ion modes in dense matter. Here, we present numerical predictions for these ion modes and demonstrate significant changes to their strength and dispersion if dissipative processes are included by Langevin dynamics. Notably, a strong diffusive mode around zero frequency arises, which is not present, or much weaker, in standard simulations. Our results have profound consequences in the interpretation of transport coefficients in dense plasmas., Studying the properties of dense plasmas is challenging due to strong interactions between electrons and ions, and numerical methods overcome this difficulty using a static thermostat. Here the authors predict a strong diffusive ion mode at low energy by including dissipative processes in the model.

Using simultaneous spectrally, angularly, and temporally resolved x-ray scattering, we measure the pronounced ion-ion correlation peak in a strongly coupled plasma. Laser-driven shock-compressed aluminum at ∼3× solid density is probed with high-energy photons at 17.9keV created by molybdenum He-α emission in a laser-driven plasma source. The measured elastic scattering feature shows a well-pronounced correlation peak at a wave vector of k=4Å-1. The magnitude of this correlation peak cannot be described by standard plasma theories employing a linear screened Coulomb potential. Advanced models, including a strong short-range repulsion due to the inner structure of the aluminum ions are however in good agreement with the scattering data. These studies have demonstrated a new highly accurate diagnostic technique to directly measure the state of compression and the ion-ion correlations. We have since applied this new method in single-shot wave-number resolved S(k) measurements to characterize the physical properties of dense plasmas. © 2014 AIP Publishing LLC.

By irradiating a thin metal foil with an intense short-pulse laser, we have created a uniform system far from equilibrium. The deposited energy is initially deposited only within the electronic subsystem, and the subsequent evolution of the system is determined by the details of the electron-phonon coupling. Here, we measure the time evolution of the lattice parameter through multilayer Bragg diffraction and compare the result to classical molecular dynamic simulations to determine the lattice temperature. The electron-ion coupling constant for gold is then determined by comparison with the evolution of a two-temperature electron-phonon system. © 2014 American Physical Society.

High-pressure solid-state transformations at high strain rates are usually observed after the fact, either during static holding or after unloading, or inferred from interferometry measurements of the sample surface. The emergence of femtosecond x-ray diffraction techniques provides insight into the dynamics of short-time-scale events such as shocks. We report laser pump-probe experiments of the response of Zr to laser-driven shocks over the first few nanoseconds of the shock event, enabling the α→ω transition and orientation relationship to be observed in real time with picosecond resolution. A clear orientation relationship of (101¯10)α||(101¯1)ω is found, in conflict with ω→α annealing experiments in zirconium and the two α→ω pathways proposed for titanium.

After they start school, low-income children lose ground to middle-income kids in reading. Some hypothesize that this growing gap in reading achievement is due, in large part, to different rates of learning during the summer months. Even small differences in summer learning accumulate over the years, making the achievement gap substantially larger at the end of elementary school than at the beginning. One longitudinal study showed that more than half of the gap in 9th-grade reading comprehension scores between low-income students and their middle-income counterparts was explained by differences in summer learning that accumulated from 1st to 5th grade (Alexander, Entwisle, and Olson 2007). The phenomenon of summer reading loss is well-known to educators, but the most commonly proposed solutions are either ineffective or too costly. However, research is pointing to an alternative approach that does work and is cost-effective.

International audience

The authors designed and implemented a voluntary reading program that was intended to reduce loss in reading achievement over the summer months, particularly for low-income and ethnic minority children. The program had two major components: providing eight books that were well matched to each child's reading level and interests end-of-year lessons and activities for teachers and parents to provide support or scaffolding for children's summer reading Teacher and parent scaffolding consisted of comprehension strategies instruction and oral reading practice. The results of two experiments demonstrated that the program had positive and educationally meaningful effects on reading achievement. These effects were largest for black and Hispanic children, ranging from 1.7 to 5.1 months of additional learning. Simply giving children books without any form of scaffolding did not have positive effects. صمم ونفذ المؤلفون برنامج القراءة الاختياري الذي هدف إلى تخفيض الاختسار في كفاءة القراءة عبر الأشهر الصيفية، لا سيما الأطفال من العرق الأقلي والدخل المنخفض. وكان لهذا البرنامج عنصران رئيسيان: 1) توفير ثمانية كتب ناسبت مستوى الطفل القرائي واهتماماته و2) القيام بدروس وأنشطة في نهاية السنة الدراسية للأساتذة والوالدين من أجل توفير دعم السقالة لقراءة الأولاد الصيفية. لقد اشتملت سقالة الأستاذ والوالد على تعليم استراتيجيات الاستيعاب وممارسة القراءة الجهرية. وأظهرت نتائج الاختبارين أن البرنامج قد كان له تأثيرات تعليمية إيجابية وذات المعنى وكانت التأثيرات أكبر للأولاد السود وذوي الأصل الإسباني تتراوح أعداد الأشهر بين 1.7 إلى 5.1 من التعلم الإضافي. وجدير بالذكر أن مجرد إعطاء الأولاد كتبا بدون أي نوع من السقالة لم يكن له أي تأثير إيجابي. 本文作者设计和实施了一个自愿阅读计划。该阅读计划的目的是减少学生（尤其是来自低收入家庭和少数族裔的学生）因在暑假中数月内缺乏阅读训练而出现阅读成绩倒退的情况。该阅读计划有两个主要部份： 一、提供八本切合儿童阅读能力和兴趣的课本。 二、为教师和家长在学年末提供指导课程与活动，以帮助或支援指导学生的暑期阅读训练。 教师和家长所提供的支援指导包括了阅读理解策略训练和朗读练习。两个有关这阅读计划的研究实验所得的结果显示，这阅读计划对学生阅读成绩有正面和有教育意义的效果。这些效果对黑人和西班牙裔儿童尤其最大，关乎1.7至 5.1个月的额外学习成效。若果只是给予学童读本而没有给予任何形式的支援指导，则不能达到任何正面效果。 Les auteurs ont concu et realise un programme de lecture volontaire visant a reduire la baisse du niveau de lecture due aux grandes vacances, en particulier pour les enfants provenant de milieu defavorise et de minorites ethniques. Ce programme avait deux composantes principales: fournir huit livres correspondant au niveau de lecture et aux interets de chaque enfant reprendre des lecons de fin d'annee et des activites pour les maitres et les parents constituant un soutien ou un etayage pour la lecture des enfants pendant l'ete. L'etayage du maitre et des parents consistait en enseignement des strategies de comprehension et en pratique de lecture orale. Les resultats des deux experiences ont prouve que ce programme produit des effets positifs et significatifs sur le plan educatif en ce qui concerne la reussite en lecture. Ces effets ont ete plus importants pour les enfants noirs et hispaniques, le gain etant de 1.7 a 5.1 mois d'apprentissage. Le fait de donner simplement des livres sans quelque etayage que ce soit n'a pas eu d'effets positifs. Авторы разработали и осуществили программу добровольного чтения, призванную нивелировать негативные последствия летнего перерыва в чтении, особенно для детей из семей с низким доходом и представителей этнических меньшинств. Программа состояла из двух важных компонентов: Детям на лето предоставляли по восемь книг, которые соответствовали уровню читательских навыков каждого ребенка и его интересам. В конце учебного года проводились специальные занятия для учителей и родителей, чтобы они могли обеспечить поддержку чтения детей во время каникул. На этих занятиях учителей и родителей обучали работать со стратегиями понимания текста и чтения вслух. Результаты двух подобных экспериментов продемонстрировали, что программа положительно и значимо влияет на успехи детей в чтении. Этот эффект был наиболее ощутим среди детей афроамериканцев и выходцев из Латинской Америки и соответствовал от 1,7 до 1,5 месяцам дополнительного обучения. Если детям просто давали книги и не оказывали при этом никакой методической поддержки, положительного эффекта не наблюдалось. Los autores disenaron e implementaron un programa de lectura con la intencion de reducir la perdida de la habilidad de leer durante los meses de verano, especialmente en los ninos de bajos recursos y de minorias etnicas. El programa consistio de dos componentes mayores: proveer ocho libros bien acoplados al nivel de lectura y los intereses de cada nino lecciones y actividades de final de ano para los maestros y los padres para que pudieran apoyar la lectura de verano de los ninos. El apoyo de los maestros y los padres consistio en instruirles sobre estrategias de comprension y como practicar la lectura en voz alta. Los resultados de dos experimentos demostraron que el programa tuvo efectos positivos y educacionalmente significativos en el progreso de la lectura. Estos efectos eran mayores en estudiantes negros e hispanos, variando desde 1.7 hasta 5.1 meses adicionales de aprendizaje. Simplemente darles libros a los ninos sin ninguna forma de apoyo no tuvo efectos positivos.

For more than 20 years, lawmakers in Texas acknowledged that offenders with special needs such as the elderly, physically handicapped, and mentally impaired who are housed in the Texas Department of Criminal Justice presented challenges in health care and cost. In response to these perceived needs, the Texas legislature created "medically recommended intensive supervision" (MRIS) to permit the early release of eligible offenders. This article examines how and why the MRIS law was implemented. It also discusses how MRIS is being utilized in Texas. Next, it delineates the MRIS process an offender must endure. The article elaborates on recent legislative attempts to amend the MRIS law. Finally, several conclusions about the use of MRIS in Texas are discussed.

Warm dense matter (WDM), which falls in the category between plasmas and condensed matter, is expected to exist in planetary interiors. Now, researchers use an X-ray laser to observe the transition to WDM.

We present measurements of electron-ion temperature equilibration in proton-heated tantalum, under warm dense matter conditions. Our results agree with theoretical predictions for metals calculated using input data from ab initio simulations. However, the fast relaxation observed in the experiment contrasts with much longer equilibration times found in proton heated carbon, indicating that the energy flow pathways in warm dense matter are far from being fully understood.

Fifteen regular grade 2 teachers used a set of 150 written lessons that were designed to develop, over the course of a school year, low and normally achieving students' ability to decode by analogy (i.e., to read unknown words using known words). The lessons provided (1) a planned sequence for teaching phonic elements including common spelling patterns and initial sounds, (2) teacher modeling of an analogy decoding strategy, and (3) analogy decoding practice with opportunities for students to transfer decoding skills to unfamiliar words. The lessons were delivered in the context of a comprehension-oriented reading program, and teachers prompted students to use an analogy decoding strategy during reading activities apart from the lessons. Results of Hierarchical Linear Modeling analyses showed significant positive relationships between the number of lessons that teachers completed and students' gains on standardized tests of word reading and reading comprehension, controlling for previous reading achievement. On additional posttests, students read 89% of the base words taught in the program and, when prompted to decode by analogy, 83% of a set of novel one-syllable words. The results show the feasibility of improving word reading and comprehension outcomes through systematic and strategic analogy-based phonics. Quince docentes de 2° grado usaron un conjunto de 150 lecciones escritas disenadas para desarrollar, en el curso de un ano escolar, las habilidades de decodificar por analogia (i.e. leer palabras desconocidas usando palabras conocidas) de estudiantes de nivel bajo y normal. Las lecciones proporcionaron: 1) una secuencia planificada para ensenar elementos fonicos incluyendo patrones de escritura comunes y sonidos iniciales, 2) la elaboracion de los docentes de una estrategia de decodificacion por analogia y 3) la practica de decodificacion por analogia con oportunidades para que los estudiantes transfirieran las habilidades de decodificacion a palabras desconocidas. Las lecciones se llevaron a cabo en el contexto de un programa de lectura orientado a la comprension y los docentes incentivaron a los estudiantes al uso de una estrategia de decodificacion por analogia durante las actividades de lectura aparte de las lecciones. Los resultados de los analisis de la modelizacion lineal jerarquica mostraron relaciones positivas significativas entre el numero de lecciones que los docentes completaron y los logros de los estudiantes en las pruebas estandarizadas de lectura de palabras y comprension lectora, controlando el nivel previo de lectura. En los post-tests adicionales, los estudiantes leyeron un 89% de las palabras basicas del programa y cuando fueron incentivados a decodificar por analogia, leyeron el 83% de un conjunto de palabras monosilabicas nuevas. Los resultados muestran la viabilidad de mejorar la lectura de palabras y la comprension mediante la intervencion fonica sistematica basada en estrategias de analogia. Funfzehn vollberuflich Lehrer der zweiten Klasse benutzten einen Satz von 150 schriftlichen Lektionen, die im Verlauf eines Schuljahres darauf ausgerichtet waren bei langsam und normal leistungsfahigen Schulern die Fahigkeit zum Entziffern durch Analogie zu entwickeln, (d.h. unbekannte Worte unter Zuhilfenahme von bekannten Wortern zu lesen). Die Unterrichtsstunden bestimmten (1) einen vorgezeichneten Ablauf zum Unterrichten phonischer Elemente einschlieslich gewohnlicher Buchstabierregeln und Anfangslauten, (2) das Modellieren der Lehrer von einer Analogiestrategie zum Entziffern und (3) Analogieentzifferungsubungen mit Moglichkeiten fur Schuler Entzifferungsfahigkeiten auf unbekannte Worte zu ubertragen. Die Lektionen wurden im Rahmen eines auf Verstandnis orientierten Leseprogrammes erteilt und die Lehrer veranlasten Schuler eine Analogieentzifferungsstrategie bei der Leseteilnahme unabhangig vom Unterricht anzuwenden. Ergebnisse der hirarchischen linearen Modellanalyse zeigte deutlich positive Verbindungen zwischen der Anzahl der von den Lehrern durchgefuhrten Lektionen und der Fortschritte der Schuler bei standartisierten Tests im Lesen von Worten und beim Leseverstandnis, sowie in der Kontrolle von fruheren Leseleistungen. Bei zusatzlichen Folgeprufungen lasen die Schuler 89% der im Programm unterrichteten Grundworte und nach Aufforderung zum Entziffern durch Analogie 83% einer Anzahl ungewohnter einsilbiger Worte. Die Ergebnisse zeigen Moglichkeiten zur Verbesserung des Lesens und Verstehens von Worten als Erfolg durch systematische und strategische analogie-basierte Phonetik. Quinze enseignants ordinaires de 2eme annee ont utilise un ensemble de 150 lecons ecrites concues pour developper, tout au long d'une annee scolaire, la capacite d'eleves faibles et moyens a decoder par analogie (c'est-a-dire a lire des mots inconnus en se servant de mots connus). Les lecons fournissaient 1) une sequence planifiee pour enseigner des elements phonetiques comportant des structures courantes a l'ecrit et des attaques phonemiques, 2) un modelage pour l'enseignant d'une strategie de decodage analogique, et 3) une pratique de decodage analogique permettant aux eleves de transferer des competences de decodage a des mots nouveaux. Les lecons ont ete delivrees dans le contexte d'un programme de lecture oriente vers la comprehension, et les enseignants ont incite les eleves a faire usage d'une strategie de decodage pendant les activites de lecture hors des lecons. Les resultats des analyses d'un Modele Lineaire Hierarchique ont montre des relations positives significatives entre le nombre de lecons que les enseignants ont effectuees et les progres des eleves dans des tests standardises de lecture de mots et de comprehension de lecture, compte tenu des resultats anterieurs en lecture. A des posttests supplementaires, les eleves ont lu 89% des mots de base enseignes dans le programme et, encourages a decoder par analogie, 83% d'un ensemble de mots monosyllabiques. Ces resultats montrent qu'il est possible de developper les resultats en lecture de mots et en comprehension au moyen d'une didactique phonetique systematique et strategique basee sur l'analogie.

We investigate subpicosecond dynamics of warm dense hydrogen at the XUV free-electron laser facility (FLASH) at DESY (Hamburg). Ultrafast impulsive electron heating is initiated by a â‰300-fs short x-ray burst of 92-eV photon energy. A second pulse probes the sample via x-ray scattering at jitter-free variable time delay. We show that the initial molecular structure dissociates within (0.9±0.2) ps, allowing us to infer the energy transfer rate between electrons and ions. We evaluate Saha and Thomas-Fermi ionization models in radiation hydrodynamics simulations, predicting plasma parameters that are subsequently used to calculate the static structure factor. A conductivity model for partially ionized plasma is validated by two-temperature density-functional theory coupled to molecular dynamic simulations and agrees with the experimental data. Our results provide important insights and the needed experimental data on transport properties of dense plasmas. © 2014 American Physical Society.

We have employed fast electrons produced by intense laser illumination to isochorically heat thermal electrons in solid density carbon to temperatures of $\ensuremath{\sim}10\text{ }000\text{ }\text{ }\mathrm{K}$. Using time-resolved x-ray diffraction, the temperature evolution of the lattice ions is obtained through the Debye-Waller effect, and this directly relates to the electron-ion equilibration rate. This is shown to be considerably lower than predicted from ideal plasma models. We attribute this to strong ion coupling screening the electron-ion interaction.

We report on the dynamics of ultrafast heating in cryogenic hydrogen initiated by a ≲300 fs, 92 eV free electron laser x-ray burst. The rise of the x-ray scattering amplitude from a second x-ray pulse probes the transition from dense cryogenic molecular hydrogen to a nearly uncorrelated plasmalike structure, indicating an electron-ion equilibration time of ∼0.9 ps. The rise time agrees with radiation hydrodynamics simulations based on a conductivity model for partially ionized plasma that is validated by two-temperature density-functional theory. © 2014 American Physical Society.

Here, we report orbital-free density-functional theory (OF DFT) molecular dynamics simulations of the dynamic ion structure factor of warm solid density aluminum at $T=0.5\text{ }\text{ }\mathrm{eV}$ and $T=5\text{ }\text{ }\mathrm{eV}$. We validate the OF DFT method in the warm dense matter regime through comparison of the static and thermodynamic properties with the more complete Kohn-Sham DFT. This extension of OF DFT to dynamic properties indicates that previously used models based on classical molecular dynamics may be inadequate to capture fully the low frequency dynamics of the response function.

Summary form only given. Extreme states of matter are routinely created in the laboratory by the interaction of a high intensity laser with a solid. Such states are created in order to study scenarios relevant to astrophysical phenomena, inertial confinement fusion (ICF), equation of state (EOS) and opacity models. Solid density material with pressures above a megabar and temperatures of thousands of Kelvin is known as warm dense matter (WDM) and lies in the region of the phase space diagram between traditional solid state and plasma physics, Since expansion techniques are no longer applicable and neither the kinetic nor the potential energy can be treated perturbatively studying WDM represents a major challenge experimentally, theoretically and computationally.

The authors charted growth of reading vocabulary for first- through fourth-grade students at three dissimilar elementary schools: School A, a suburban school enrolling While students who spoke standard English; School B, an inner-city school enrolling Black, dialect-speaking students; and School C, a semirural school enrolling economically disadvantaged, dialect-speaking Asian/Pacific students

Molecular mechanics calculations have been used to study the external noncovalent complexes formed between DNA and the strong carcinogen, aflatoxin B1. Three different sequences of hexameric duplexes were used for the DNA. Both the aflatoxin B1 parent molecule and its ultimate carcinogenic form, a carbocation, were modeled. The results are compared with recent experimental data on sequence specificity of the covalent attachment of aflatoxin to sites on the nucleotide bases. The comparison is discussed in light of a recently proposed hypothesis suggesting that the locus of carbocation formation is in acidic domains near the surface of the macroion and this determines the site of covalent adduct formation.

Dense cryogenic hydrogen is heated by intense femtosecond infrared laser pulses at intensities of 1015-1016 Wcm-2. Three-dimensional particle-in-cell (PIC) simulations predict that this heating is limited to the skin depth, causing an inhomogeneously heated outer shell with a cold core and two prominent temperatures of about 25 and 40 eV for simulated delay times up to +70 fs after the laser pulse maximum. Experimentally, the time-integrated emitted bremsstrahlung in the spectral range of 8-18 nm was corrected for the wavelength-dependent instrument efficiency. The resulting spectrum cannot be fit with a single temperature bremsstrahlung model, and the best fit is obtained using two temperatures of about 13 and 30 eV. The lower temperatures in the experiment can be explained by missing energy-loss channels in the simulations, as well as the inclusion of hot, non- Maxwellian electrons in the temperature calculation. We resolved the time-scale for laser-heating of hydrogen, and PIC results for laser-matter interaction were successfully tested against the experiment data.

Objective To present a case report of folie simultanée in monozygotic twins. The literature describing folie à deux in twins is also reviewed and the common clinical findings are presented. Method Case presentation and review of the literature. Results Clinical observations of monozygotic twins with folie simultanée suggest that the delusions tend to progress over time with each twin reinforcing the delusion in the second. Conclusions The concept of a delusion resonating between individuals may account for the rapid progression and escalation of these delusions.

Recent experiments performed at the Matter in Extreme Conditions end station of the Linac Coherent Light Source (LCLS) have demonstrated the first spectrally resolved measurements of plasmons from isochorically heated aluminum. The experiments have been performed using a seeded 8-keV x-ray laser beam as a pump and probe to both volumetrically heat and scatter x-rays from aluminum. Collective x-ray Thomson scattering spectra show a well-resolved plasmon feature that is down-shifted in energy by 19 eV. In addition, Mbar shock pressures from laser-compressed aluminum foils using velocity interferometer system for any reflector have been measured. The combination of experiments fully demonstrates the possibility to perform warm dense matter studies at the LCLS with unprecedented accuracy and precision.