Teachers\u27 Perceptions of Manipulatives During Middle School Math Instruction

In a Colorado school district, school personnel and parents were concerned that middle school math proficiency levels were low for 2011-2014 and math teachers were not using manipulatives in their classes to increase math performance. The district\u27s math coordinator did not foresee providing specific professional development (PD) for math manipulative use to address these concerns. Without this PD, math teachers may be ill-quipped to teach math concepts when using manipulatives, which, in turn, could lead to further poor math performance. The purpose of this qualitative bounded collective case study was to explore middle school teachers\u27 perceptions of PD and perceived self-efficacy regading the implementation of manipulatives. Knowles\u27s andragogy and Piaget\u27s cognitive development theories framed this study. A homogeneous sample of 12 voluntary participants with more than 5 years teaching middle school math, both with and without access to manipulatives, volunteered to participate in this study. Data from observations, interviews, and archival documents were analyzed using comparative and inductive analyses and were analytically coded. Participants reported a need for PD that focused on physical and virtual manipulatives (PM and VM) and a low perceived self-efficacy regarding manipulatives use during math instruction. A blended PD using face-to-face and distance learning formats was designed to increase math teachers\u27 knowledge of and perceived self-efficacy with PM and VM for math instruction. This endeavor may contribute to positive social change by reforming PD opportunities to support teachers\u27 practice and self-efficacy using manipulatives during math instruction, ultimately increasing student performance

All-Optical Clock Recovery for NRZ-DPSK Signals

We experimentally demonstrate an optical clock recovery scheme for nonreturn-to-zero differential phase shifting keying (NRZ-DPSK) data. By using an optical circuit made by a proper fiber Bragg filter and a Fabry-Pérot based clock extraction circuit, we obtain a stable and low jitter 10-GHz optical clock signal. This signal shows comparable performance with the original electrical clock in bit-error-rate measurements and oscilloscope triggering operation

Single and Multicast Wavelength Conversion at 40 Gb/s by means of Fast Nonlinear-Polarization-Switching in an SOA

We experimentally demonstrate all-optical wavelength conversion of a 40-Gb/s nonreturn-to-zero signal by means of nonlinear polarization switching in a single semiconductor optical amplifier (SOA). Using a highly nonlinear SOA optimized for very fast gain recovery time, we observe no appreciable penalty for the conventional (single) wavelength conversion. We also obtain, for the first time by using this technique, the simultaneous multiconversion to different wavelengths (four on a 200-GHz frequency grid) of an input signa

Transcriptional activation of the miR-17-92 cluster is involved in the growth-promoting effects of MYB in human Ph-positive leukemia cells.

MicroRNAs, non-coding regulators of gene expression, are likely to function as important downstream effectors of many transcription factors including MYB. Optimal levels of MYB are required for transformation/maintenance of BCR-ABL-expressing cells. We investigated whether MYB silencing modulates microRNA expression in Philadelphia-positive (Ph+) leukemia cells and if MYB-regulated microRNAs are important for the MYB addiction of these cells. Thirty-five microRNAs were modulated by MYB silencing in lymphoid and erythromyeloid chronic myeloid leukemia-blast crisis BV173 and K562 cells; 15 of these were concordantly modulated in both lines. We focused on the miR-17-92 cluster because of its oncogenic role in tumors and found that: i) it is a direct MYB target; ii) it partially rescued the impaired proliferation and enhanced apoptosis of MYB-silenced BV173 cells. Moreover, we identified FRZB, a Wnt/β-catenin pathway inhibitor, as a novel target of the miR-17-92 cluster. High expression of MYB in blast cells from 2 Ph+leukemia patients correlated positively with the miR-17-92 cluster and inversely with FRZB. This expression pattern was also observed in a microarray dataset of 122 Ph+acute lymphoblastic leukemias. In vivo experiments in NOD scid gamma mice injected with BV173 cells confirmed that FRZB functions as a Wnt/β-catenin inhibitor even as they failed to demonstrate that this pathway is important for BV173-dependent leukemogenesis. These studies illustrate the global effects of MYB expression on the microRNAs profile of Ph+cells and supports the concept that the MYB addiction of these cells is, in part, caused by modulation of microRNA-regulated pathways affecting cell proliferation and survival. Copyright© 2019 Ferrata Storti Foundation

A pilot study of the radio-continuum emission from MASH planetary nebulae

We report an Australia Telescope Compact Array (ATCA) radio-continuum observations of 26 planetary nebulae (PNe) at wavelengths of 3 and 6 cm. This sample of 26 PNe were taken from the Macquarie/AAO/Strasbourg Halpha PNe (MASH) catalogue and previous lists. We investigate radio detection quality including measured and derived parameters for all detected or marginally detected PNe from this combined sample. Some 11 objects from the observed sample have been successfully detected and parametrized. Except for one, all detected PNe have very low radio surface brightnesses. We use a statistical distance scale method to calculate distances and ionised masses of the detected objects. Nebulae from this sample are found to be large (>0.2 pc in diameter) and highly diluted which indicates old age. For 21 PNe from this sample we list integrated Halpha fluxes and interstellar extinction coefficients, either taken from the literature or derived here from the Balmer decrement and radio to Halpha ratio methods. Finally, our detected fraction of the MASH pilot sample is relatively low compared to the non-MASH sub-sample. We conclude that future radio surveys of the MASH sample must involve deeper observations with better uv coverage in order to increase the fraction of detected objects and improve the quality of the derived parameters.Comment: 9 pages, 2 figures, and 5 tables. Accepted for publication in Astron. Nach

Study of an intrinsically safe infrastructure for training and research on nuclear technologies

Within European Partitioning & Transmutation research programs, infrastructures specifically dedicated to the study of fundamental reactor physics and engineering parameters of future fast-neutron-based reactors are very important, being some of these features not available in present zero-power prototypes. This presentation will illustrate the conceptual design of an Accelerator-Driven System with high safety standards, but ample flexibility for measurements. The design assumes as base option a 70MeV, 0.75mA proton cyclotron, as the one which will be installed at the INFN National Laboratory in Legnaro, Italy and a Beryllium target, with Helium gas as core coolant. Safety is guaranteed by limiting the thermal power to 200 kW, with a neutron multiplication coefficient around 0.94, loading the core with fuel containing Uranium enriched at 20% inserted in a solid-lead diffuser. The small decay heat can be passively removed by thermal radiation from the vessel. Such a system could be used to study, among others, some specific aspects of neutron diffusion in lead, beam-core coupling, target cooling and could serve as a training facility

VISION - Vienna survey in Orion I. VISTA Orion A Survey

Stefan Meingast, et al., “VISION – Vienna survey in Orion”, Astronomy & Astrophysics, Vol. 587, March 2016. This version of record is available online at:https://www.aanda.org/articles/aa/abs/2016/02/aa26100-15/aa26100-15.html © ESO, 2016Orion A hosts the nearest massive star factory, thus offering a unique opportunity to resolve the processes connected with the formation of both low- and high-mass stars. Here we present the most detailed and sensitive near-infrared (NIR) observations of the entire molecular cloud to date. With the unique combination of high image quality, survey coverage, and sensitivity, our NIR survey of Orion A aims at establishing a solid empirical foundation for further studies of this important cloud. In this first paper we present the observations, data reduction, and source catalog generation. To demonstrate the data quality, we present a first application of our catalog to estimate the number of stars currently forming inside Orion A and to verify the existence of a more evolved young foreground population. We used the European Southern Observatory's (ESO) Visible and Infrared Survey Telescope for Astronomy (VISTA) to survey the entire Orion A molecular cloud in the NIR $J, H$, and $K_S$ bands, covering a total of $\sim$18.3 deg$^2$. We implemented all data reduction recipes independently of the ESO pipeline. Estimates of the young populations toward Orion A are derived via the $K_S$-band luminosity function. Our catalog (799995 sources) increases the source counts compared to the Two Micron All Sky Survey by about an order of magnitude. The 90% completeness limits are 20.4, 19.9, and 19.0 mag in $J, H$, and $K_S$, respectively. The reduced images have 20% better resolution on average compared to pipeline products. We find between 2300 and 3000 embedded objects in Orion A and confirm that there is an extended foreground population above the Galactic field, in agreement with previous work. The Orion A VISTA catalog represents the most detailed NIR view of the nearest massive star-forming region and provides a fundamental basis for future studies of star formation processes toward Orion.Peer reviewe