Classroom Environments of Coaching and Non-Coaching Teachers at a Large Midwestern High School

This descriptive study examined the classroom environments of coaching and non-coaching teachers. The purpose of examining factors involving classroom environments is to help determine what the best possible learning environment is for both teachers and students. In this study, high school teachers and teacher-coaches were asked to give their perceptions of the environment of a single class period during the school day. Research done in this area has focused on the perceptions of students and has subsequently used and compared this data to describe the ideal and real classroom environment. This study, comparing teachers and teacher-coaches, used the Short Form version of the Classroom Environment Scale. This instrument contains 24 questions divided into 6 dimensions. The subjects of the study were asked to give yes or no responses to questions contained within each of the dimensions: involvement, affiliation, teacher support, task orientation, order and organization, and rule clarity. Data from the study was analyzed and the following divisions of the sample groups were compare: coaches and non-coaches, male and female coaches, coaches with differing years of teaching experience, and coaches with differing levels of academic advancement. The mean scores of coaches and non-coaches were calculated and all groups were compared according to each of the six dimensions of the study. Results of the study showed that the perceptions related to classroom environments of coaching-teachers in regards to teacher support and classroom affiliation are higher than the perceptions of non-coaching teachers

Nanoscale austenite reversion through partitioning, segregation, and kinetic freezing: Example of a ductile 2 GPa Fe-Cr-C steel

Austenite reversion during tempering of a Fe-13.6Cr-0.44C (wt.%) martensite results in an ultrahigh strength ferritic stainless steel with excellent ductility. The austenite reversion mechanism is coupled to the kinetic freezing of carbon during low-temperature partitioning at the interfaces between martensite and retained austenite and to carbon segregation at martensite-martensite grain boundaries. An advantage of austenite reversion is its scalability, i.e., changing tempering time and temperature tailors the desired strength-ductility profiles (e.g. tempering at 400{\deg}C for 1 min. produces a 2 GPa ultimate tensile strength (UTS) and 14% elongation while 30 min. at 400{\deg}C results in a UTS of ~ 1.75 GPa with an elongation of 23%). The austenite reversion process, carbide precipitation, and carbon segregation have been characterized by XRD, EBSD, TEM, and atom probe tomography (APT) in order to develop the structure-property relationships that control the material's strength and ductility.Comment: in press Acta Materialia 201

Site-selective protein modification via disulfide rebridging for fast tetrazine/trans-cyclooctene bioconjugation

An inverse electron demand Diels–Alder reaction between tetrazine and trans-cyclooctene (TCO) holds great promise for protein modification and manipulation. Herein, we report the design and synthesis of a tetrazine-based disulfide rebridging reagent, which allows the site-selective installation of a tetrazine group into disulfide-containing peptides and proteins such as the hormone somatostatin (SST) and the antigen binding fragment (Fab) of human immunoglobulin G (IgG). The fast and efficient conjugation of the tetrazine modified proteins with three different TCO-containing substrates to form a set of bioconjugates in a site-selective manner was successfully demonstrated for the first time. Homogeneous, well-defined bioconjugates were obtained underlining the great potential of our method for fast bioconjugation in emerging protein therapeutics. The formed bioconjugates were stable against glutathione and in serum, and they maintained their secondary structure. With this work, we broaden the scope of tetrazine chemistry for site-selective protein modification to prepare well-defined SST and Fab conjugates with preserved structures and good stability under biologically relevant conditions

Non-Newtonian Mechanics

The classical motion of spinning particles can be described without employing Grassmann variables or Clifford algebras, but simply by generalizing the usual spinless theory. We only assume the invariance with respect to the Poincare' group; and only requiring the conservation of the linear and angular momenta we derive the zitterbewegung: namely the decomposition of the 4-velocity in the newtonian constant term p/m and in a non-newtonian time-oscillating spacelike term. Consequently, free classical particles do not obey, in general, the Principle of Inertia. Superluminal motions are also allowed, without violating Special Relativity, provided that the energy-momentum moves along the worldline of the center-of-mass. Moreover, a non-linear, non-constant relation holds between the time durations measured in different reference frames. Newtonian Mechanics is re-obtained as a particular case of the present theory: namely for spinless systems with no zitterbewegung. Introducing a Lagrangian containing also derivatives of the 4-velocity we get a new equation of the motion, actually a generalization of the Newton Law a=F/m. Requiring the rotational symmetry and the reparametrization invariance we derive the classical spin vector and the conserved scalar Hamiltonian, respectively. We derive also the classical Dirac spin and analyze the general solution of the Eulero-Lagrange equation for Dirac particles. The interesting case of spinning systems with zero intrinsic angular momentum is also studied.Comment: LaTeX; 27 page

Viscous coalescence of droplets: a Lattice Boltzmann study

The coalescence of two resting liquid droplets in a saturated vapor phase is investigated by Lattice Boltzmann simulations in two and three dimensions. We find that, in the viscous regime, the bridge radius obeys a t^{1/2}-scaling law in time with the characteristic time scale given by the viscous time. Our results differ significantly from the predictions of existing analytical theories of viscous coalescence as well as from experimental observations. While the underlying reason for these deviations is presently unknown, a simple scaling argument is given that describes our results well.Comment: 12 pages, 10 figures; as published in Phys. Fluid

A Model-Based Framework for Simplified Collaboration of Legal and Software Experts in Data Protection Assessments

The protection of personal data has become an increasingly important issue. Legal norms focused on data protection, such as the GDPR, provide legally binding requirements for systems that process personal data. Article 25 of the GDPR refers to the obligation to Data Protection by Design and Default. This can be achieved by conducting DPLA of the system in the early stages of development and implementing data protection concepts where necessary. This ties in with Article 35, which refers to an obligation to conduct DPLA before the actual processing of data. To aid in conducting continuous DPLA during the design time of software systems, we propose a model-based collaboration framework. This framework not only aids in providing consistent views of the software system for legal experts and software architects but also simplifies communication between both parties. We discuss the overall goals and benefits of such a framework and go into detail about the processes that interact as part of the framework. We also try to align legal concepts with the processes and describe the continuous iterative development using the collaboration framework

Radiation effects on the blood-brain barrier

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Nuclear Science and Engineering, 2007.Includes bibliographical references (p. 53-56).Selective vascular irradiation enables the critical examination of the vasculature and its role in the onset of late radiation effects. It is a novel approach to expose the endothelial cells to much higher levels of ionizing radiation relative to normal cells by utilizing the boron neutron capture reaction. When boron-containing compounds are restricted to the lumen of the blood vessel, the resulting high-LET alpha and lithium particles cannot deposit their energy in the normal cells beyond the vasculature after the target is exposed to thermal neutrons. This allows for a 2- to 3-fold increase in the calculated dose to the endothelial cells. However, this technique has been criticized because there is no direct evidence that the endothelial cells receive an absorbed dose from the selective vascular irradiation. The objective of this work is to provide corroborating experimental evidence that selective vascular irradiation physically damages the endothelial cells. An established assay utilizing blood-brain barrier disruption was adopted to quantify the radiation damage to the endothelial cells in female BALB/C mice, 8-12 weeks of age. A dye that attaches to the plasma proteins in the blood and that is ordinarily kept out of the brain by the blood-brain barrier is injected into the blood supply before the irradiation, and following irradiation, damage to the vasculature will result in disruption of the blood-brain barrier that allows blood stained with the dye to enter the brain. After sacrificing, the blood in the vessel lumen is cleared by performing a trans-cardiac perfusion, and the brain is homogenized and prepared for analysis. The absorbance of the resulting supernatant of each brain sample is measured with a spectrophotometer at the optimal wavelength of the dye.(cont.) The absorbance is related to the quantity of blood that leaked through the blood-brain barrier, which is also related to the damage caused to the vasculature from exposure to ionizing radiation. Increased leakage through the blood-brain barrier was observed for those mice exposed to selective vascular irradiation, indicating a direct relationship between the leakage through the blood-brain barrier and the 10B concentration in the blood. The most significant increase in the leakage through the blood-brain barrier (p<0.002) was observed at the highest lOB concentration in the blood (161 ppm). The compound biological effectiveness (CBE) for sulfhydryl borane (BSH) was calculated to be 0.28, which is consistent with the published value of the CBE for BSH in the rat spinal cord. This suggests that the assumptions used for calculating the absorbed doses for selective vascular irradiation are reasonable and approximate to what the endothelial cells receive.by Rebecca L. Raabe.S.M

Shear-induced anisotropic decay of correlations in hard-sphere colloidal glasses

Spatial correlations of microscopic fluctuations are investigated via real-space experiments and computer simulations of colloidal glasses under steady shear. It is shown that while the distribution of one-particle fluctuations is always isotropic regardless of the relative importance of shear as compared to thermal fluctuations, their spatial correlations show a marked sensitivity to the competition between shear-induced and thermally activated relaxation. Correlations are isotropic in the thermally dominated regime, but develop strong anisotropy as shear dominates the dynamics of microscopic fluctuations. We discuss the relevance of this observation for a better understanding of flow heterogeneity in sheared amorphous solids.Comment: 6 pages, 4 figure