In the experiments stick insects walk on an inclined substrate such that the legs of one side of the body point uphill and the legs of the other side point downhill. In this situation the vertical ...axis of the body is rotated against the inclination of the substrate as if to compensate for the effect of substrate inclination. A very small effect has been found when the experiment was performed with animals standing on a tilted platform which shows that the effect depends on the behavioral context. When, however, animals first walked along the inclined surface and then, before measurement, stopped walking spontaneously, a rotation of the body has been observed similar to that in walking animals. In a second experiment it was tested whether the observed body rotation is caused by the change of direction of gravity vector or by the fact that on an inclined surface gravity necessarily has a component pulling the body sideways. Experiments with animals standing on horizontal ground and additional weights applied pulling the body to the side showed similar body rotations supporting the latter idea. In a simulation study it could be shown that the combined activity of proportional feedback controllers in the leg joints is sufficient to explain the observed behavior. This is however only possible if the gain factors of coxa-trochanter joint controller and of femur-tibia joint controller show a ratio in the order of 1 : 0.05 to 1 : 1.8. In order to describe the behavior of animals standing on a tilted platform, a ratio of 1 : 1.7 is necessary. In walking animals, this body rotation requires to change the trajectories of stance and swing movements. The latter have been studied in more detail. During swing, the femur-tibia joint is more extended in the uphill legs. Conversely, the coxa-trochanter joint appears to be more elevated in the downhill legs which compensates the smaller lift in the femur-tibia joint. The results are discussed in the context of different hypotheses.
This commentary describes the limitations of 40-minute class period times. The forty-minute system makes hash of the lives of teachers, especially in small schools, and about 80 percent of high ...schools have fewer than two hundred pupils. These small schools crowd their forty-minute periods with as many diverse and unrelated activities as possible, forcing teachers to prepare multiple subjects, some of which they may not yet have mastered. A serious outcome of this arrangement is that students are pulled between diverse and conflicting stimuli. This issue is projected to get worse before it gets better, as major subject teachers have powerful organization decision-makers that can pull strings to keep their subjects in the schedule program. This article was originally published in "School Review" v53, no. 3, p162-169 (March 1945) It is reprinted here with the kind permission of the University of Chicago Press.
The number of samples in biological experiments is continuously increasing, but complex protocols and human error in many cases lead to suboptimal data quality and hence difficulties in reproducing ...scientific findings. Laboratory automation can alleviate many of these problems by precisely reproducing machine‐readable protocols. These instruments generally require high up‐front investments, and due to the lack of open application programming interfaces (APIs), they are notoriously difficult for scientists to customize and control outside of the vendor‐supplied software. Here, automated, high‐throughput experiments are demonstrated for interdisciplinary research in life science that can be replicated on a modest budget, using open tools to ensure reproducibility by combining the tools OpenFlexure, Opentrons, ImJoy, and UC2. This automated sample preparation and imaging pipeline can easily be replicated and established in many laboratories as well as in educational contexts through easy‐to‐understand algorithms and easy‐to‐build microscopes. Additionally, the creation of feedback loops, with later pipetting or imaging steps depending on the analysis of previously acquired images, enables the realization of fully autonomous “smart” microscopy experiments. All documents and source files are publicly available to prove the concept of smart lab automation using inexpensive, open tools. It is believed this democratizes access to the power and repeatability of automated experiments.
This study describes how the combination of different open‐source hard‐ and software projects can form a cutting‐edge lab automation setup with high‐throughput robotic microscopy (UC2 and OpenFlexure), automated sample preparation (Opentrons), and image processing (Imjoy). Publicly available documentation guides the user through the process of replicating the setup.
“Self-correcting homework” is the name used at Educational Testing Service for exercises in which the intended answer to each question or problem is printed somewhere near the space in which the ...student writes or chooses an answer. While he is working on an item, the intended answer is covered up, but as soon as he has recorded his own answer, he can move either the page or the cover and find out whether he was right or wrong. If he was wrong, he finds out immediately what was right.
Since no machinery is used to perform these simple operations, it
Reflects on a long career concerning teaching and testing at the secondary and college level. Talks about the relationship between secondary school testing and preparation, college entrance ...standards, and trends in college course organization and testing. (TB)
In the experiments stick insects walk on an inclined substrate such that the legs of one side of the body point uphill and the legs of the other side point downhill. In this situation the vertical ...axis of the body is rotated against the inclination of the substrate as if to compensate for the effect of substrate inclination. A very small effect has been found when the experiment was performed with animals standing on a tilted platform which shows that the effect depends on the behavioral context. When, however, animals first walked along the inclined surface and then, before measurement, stopped walking spontaneously, a rotation of the body has been observed similar to that in walking animals. In a second experiment it was tested whether the observed body rotation is caused by the change of direction of gravity vector or by the fact that on an inclined surface gravity necessarily has a component pulling the body sideways. Experiments with animals standing on horizontal ground and additional weights applied pulling the body to the side showed similar body rotations supporting the latter idea. In a simulation study it could be shown that the combined activity of proportional feedback controllers in the leg joints is sufficient to explain the observed behavior. This is however only possible if the gain factors of coxa-trochanter joint controller and of femur-tibia joint controller show a ratio in the order of 1 : 0.05 to 1 : 1.8. In order to describe the behavior of animals standing on a tilted platform, a ratio of 1 : 1.7 is necessary. In walking animals, this body rotation requires to change the trajectories of stance and swing movements. The latter have been studied in more detail. During swing, the femur-tibia joint is more extended in the uphill legs. Conversely, the coxa-trochanter joint appears to be more elevated in the downhill legs which compensates the smaller lift in the femur-tibia joint. The results are discussed in the context of different hypotheses.
We have measured the cross section for quasielastic 1p-shell proton knockout in the 16O(e,e′p) reaction at ω=0.439GeV and Q2=0.8(GeV/c)2 for missing momentum Pmiss≤355MeV/c. We have extracted the ...response functions RL+TT, RT, RLT, and the left-right asymmetry, ALT, for the 1p1/2 and the 1p3/2 states. The data are well described by relativistic distorted wave impulse approximation calculations. At large Pmiss, the structure observed in ALT indicates the existence of dynamical relativistic effects. (APS)
We measured the cross section and response functions for the quasielastic {sup 16}O( e,E{dagger}p) reaction for missing energies 25{le}E{sub m}{le}120 MeV at missing momenta P{sub m}{le}340 MeV/c . ...For 25{lt}E{sub m}{lt}50 MeV and P{sub m}{approximately}60 MeV/c , the reaction is dominated by a single 1s{sub 1/2} proton knockout. At larger P{sub m} , the single-particle aspects are increasingly masked by more complicated processes. Calculations which include pion exchange currents, isobar currents, and short-range correlations account for the shape and the transversity, but for only half of the magnitude of the measured cross section.
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