Effective Use of Formative Assessment by High School Teachers

The purpose of this mixed-methods study was to gain insights and understandings of high school teachers’ perceptions and use of formative assessment to enhance their planning, individualization of instruction, and adjustment of course content to improve student learning. The study was conducted over two years in a midwestern high school of approximately 1,000 students. Crucial to the three project teachers’ understanding of formative assessment was developing and using preset curriculum road maps that tightly aligned course goals, learning objectives, activities, instructional methods, and assessment. The in-depth case studies of the sample’s three teachers revealed that, when provided with specific information about formative assessment through staff development, they became more positive toward such assessment, and their implementation skills were greatly improved. The staff development had an especially positive impact on the teachers’ understanding and skill sets for individualizing instructional practices. The personalization of the staff development proved to be the most beneficial when it tailored the content to the varying levels of initial proficiency of the three sample teachers. Support for formative assessment by the administrative team members was essential to creating a cultural shift from summative to formative assessment. Accessed 5,436 times on https://pareonline.net from October 06, 2017 to December 31, 2019. For downloads from January 1, 2020 forward, please click on the PlumX Metrics link to the right

A new Taxonomy of Continuous Global Optimization Algorithms

Surrogate-based optimization, nature-inspired metaheuristics, and hybrid combinations have become state of the art in algorithm design for solving real-world optimization problems. Still, it is difficult for practitioners to get an overview that explains their advantages in comparison to a large number of available methods in the scope of optimization. Available taxonomies lack the embedding of current approaches in the larger context of this broad field. This article presents a taxonomy of the field, which explores and matches algorithm strategies by extracting similarities and differences in their search strategies. A particular focus lies on algorithms using surrogates, nature-inspired designs, and those created by design optimization. The extracted features of components or operators allow us to create a set of classification indicators to distinguish between a small number of classes. The features allow a deeper understanding of components of the search strategies and further indicate the close connections between the different algorithm designs. We present intuitive analogies to explain the basic principles of the search algorithms, particularly useful for novices in this research field. Furthermore, this taxonomy allows recommendations for the applicability of the corresponding algorithms.Comment: 35 pages total, 28 written pages, 4 figures, 2019 Reworked Versio

Potential impacts of chemical weathering on feldspar luminescence dating properties

Chemical weathering alters the chemical composition of mineral grains. As a result, trapped-charge dating signals of primary silicates may be progressively modified. In this study, we treated three feldspar specimens to understand the effect of proton- and ligand-promoted dissolution on their luminescence properties. We conducted kinetic experiments over 720 h using two solutions: (1) oxalic acid (pH 3, 20 ∘C), an organic acid with chelating abilities, and (2) aqua regia (pH < 1, 40 ∘C), a mixture of strong acids creating aggressive acid hydrolysis conditions. These two solutions were chosen to provoke, on laboratory timescales, some of the changes that may occur on geological timescales as minerals weather in nature. The effect of the extracting solutions on mineral dissolution was investigated by monitoring the concentration of dissolved elements, while changes in feldspar surface morphology were assessed by scanning electron microscopy (SEM). Subsequent changes in feldspar luminescence in the near-UV (∼ 340 nm) and blue (∼ 410 nm) thermoluminescence (TL) and infrared stimulated luminescence (IRSL) emission bands were assessed at the multi- and/or single-grain levels to gain insight into the emission spectra, dose response, saturation, and anomalous fading characteristics of the feldspars. In all experiments, only minor feldspar dissolution was observed after 720 h. In general, aqua regia, the more chemically aggressive solution, had a larger effect on feldspar dissolution compared to that of oxalic acid. Additionally, our results showed that although the TL and IRSL intensities changed slightly with increasing artificial weathering time, the feldspar luminescence properties were otherwise unmodified. This suggests that chemical alteration of feldspar surfaces may not affect luminescence dating signals obtained from natural samples

Photometric variability of the LAMOST sample of magnetic chemically peculiar stars as seen by TESS

High-quality light curves from space missions have opened up a new window on the rotational and pulsational properties of magnetic chemically peculiar (mCP) stars and have fuelled asteroseismic studies. They allow the internal effects of surface magnetic fields to be probed and numerous astrophysical parameters to be derived with great precision. We present an investigation of the photometric variability of a sample of 1002 mCP stars discovered in the LAMOST archival spectra with the aims of measuring their rotational periods and identifying interesting objects for follow-up studies. TESS photometry was available for 782 mCP stars and was analysed using a Fourier two-term frequency fit to determine the stars' rotational periods. The rotational signal was then subtracted from the light curve to identify non-rotational variability. A pixel-level blending analysis was performed to check whether the variability originates in the target star or a nearby blended neighbour. We investigated correlations between the rotational periods, fractional age on the main sequence, mass, and several other observables. We present rotational periods and period estimates for 720 mCP stars. In addition, we identified four eclipsing binary systems that likely host an mCP star, as well as 25 stars with additional signals consistent with pulsation (12 stars with frequencies above 10 d$^{-1}$ and 13 stars with frequencies below 10 $^{-1}$). We find that more evolved stars have longer rotation periods, in agreement with the assumption of the conservation of angular momentum during main-sequence evolution. With our work, we increase the sample size of mCP stars with known rotation periods and identify prime candidates for detailed follow-up studies. This enables two paths towards future investigations: population studies of even larger samples of mCP stars and the detailed characterisation of high-value targets.Comment: 30 pages, 9 figures, 1 table. Accepted for publication in the Journal of Astronomy and Astrophysics (A&A

A lidar system for remote probing of the lower atmosphere

The development and characteristics of a lidar system for atmospheric measurements are discussed. The lidar system employs a Q-switched ruby laser that radiates an intense pulse of light into the atmosphere to illuminate aerosol particles in the laser beam. Light backscattered from the particles is received by a Cassegrain telescope equipped with a sensitive photomultiplier tube. The output signal of the photomultiplier tube is displayed on an oscilloscope and recorded on polaroid film