What Do Introductory Students Learn by Creating Shareable Digital Artifacts?

In this critical reflection, an instructor of Introduction to Creative Writing discusses student learning from the study and creation of “sharable digital artifacts”—for example poem films and Instagram poetry. This practice benefits both non-majors and majors as students make gains in specific skills of revision, metaphor making, and image creation. Further, students make gains in threshold concepts of creative writing through the activity of transferring their knowledge across creative writing genres

Triggering p53 after cytokinesis failure

Cells that fail to divide during cytokinesis often arrest in the next G1 phase by a mysterious mechanism that depends upon p53. What triggers this arrest is unclear. New studies, including a report in this issue (Uetake and Sluder, 2004) suggest that this arrest does not occur because cells are polyploid, are binucleate, have multiple centrosome, or have failed cytokinesis, making this phenomenon even more puzzling

Blue-green opponency and trichromatic vision in the greenhouse whitefly (Trialeurodes vaporariorum)

Visual orientation in the greenhouse whitefly ( Trialeurodes vaporariorum Westwood, Hemiptera: Aleyrodidae) is the result of 9wavelength-specific behaviours9. Green-yellow elicits 9settling behaviour9 while ultraviolet (UV) radiation initiates 9migratory behaviour9. Electroretinograms of the photoreceptors9 spectral efficiency showed peaks in the green and the UV range and whitefly vision was said to be dichromatic. In order to study the visual behaviour of T. vaporariorum , nineteen narrow-bandwidth LEDs covering the UV-A and visible range were used in combination with light scattering acrylic glass screens in a small-scale choice arena under greenhouse conditions. Multiple-choice and dual-choice assays were performed, resulting in LED-based behavioural action spectra of settling (green) and migratory behaviour (UV). A potential inhibitory blue-green chromatic mechanism was studied by combining yellow with different blueish LEDs. Intensity dependencies were illustrated by changing LED intensities. Regarding the 9settling response9, highest attraction was achieved by a green LED with a centroid wavelength of 550 nm, while a blue LED with 469 nm proved to be most inhibitory. Behaviour was distinctly intensity dependent. 9Migratory behaviour9 was elicited the most by the UV LED with the shortest available wavelength of 373 nm. The results clearly prove the presence of a green and a yet undescribed blue sensitive photoreceptor and a blue-green opponent mechanism. Furthermore, empirical colour choice models were built and receptor peaks were estimated around 510 - 520 nm (green), 480 - 490 nm (blue) and 340 - 370 nm (UV). Consequently, Trialeurodes vaporariorum possesses a trichromatic receptor setup

Cell Division: Righting the Check

SummaryStudies in fission and budding yeast have continuously led the way for analyzing pathways of cell division. Two elegant studies, one from each yeast species, are opening the gates to study one of the final steps of mitosis — silencing the spindle checkpoint

Recent Developments--Recent Decisions

All nations recognize the enormous problem of marine pollution. The sources of marine pollution are definable, and there are methods by which these sources may be restricted. Virtually all mankind would prefer less pollution to more. Prevention, however, becomes less attractive in light of its costs, which assume both political and economic characteristics. Varying political and economic climates coupled with problems of sovereignty and national self-interest render agreement on the imposition of standards difficult. This Recent Development will chart past and present efforts at the preservation of the marine environment, consider the issues confronting the United Nations Third Conference on the Law of the Sea and the United Nations Environment Program, and attempt to predict future approaches to this area of international law. ================== Plaintiffs, the New York Shipping Association (NYSA) and the International Longshoremen\u27s Association, AFL-CIO (ILA) filed a joint petition with the Federal Maritime Commission (FMC) for an order declaring that a formula in their collective bargaining agreement was not subject to the filing or approval requirements of section 15 of the Shipping Act of 1916. The formula in question established a method for assessing charges to fund a benefit plan created to mitigate the impact on longshoremen of unemployment caused by technological innovation. Petitioners alleged that the formula was not an agreement between persons subject to the Act and, therefore, was not within the purview of section 15. In addition, they argued that because the assessment arrangement was part of the collective bargaining agreement between NYSA and ILA, it was exempt from the provisions of the Act in all respects

Timing of Events in Mitosis

AbstractBackground: Regulation of the major transitions in the cell cycle, such as G1/S, G2/M, and metaphase to anaphase, are increasingly well understood. However, we have a poor understanding of the timing of events within each phase of the cell cycle, such as S phase or early mitosis. Two extreme models of regulation are possible. A “regulator-controlled model” in which the order of events is governed by the activation of a series of cytoplasmic regulators, such as kinases, phosphatases, or proteases; or a “substrate-controlled model” in which temporal regulation is determined by the differential responses of the cellular machinery to a common set of activators.Results: We have tried to distinguish between these two models by examining the timing of both biochemical and morphological events in Xenopus egg extracts during mitosis. Several proteins respond with different delays to the activation of Cdc2. We have found that the timing of phosphorylation is largely unchanged when these proteins are exposed to extracts that have been in mitosis for various periods of time. Similarly, when Xenopus interphase nuclei are added to extracts at different times after the G2/M transition, they undergo all the expected morphological changes in the proper sequence and with very similar kinetics.Conclusions: Our results suggest that during early mitosis (from prophase to metaphase) the timing of biochemical events (such as phosphorylation) and morphological events (such as structural changes in the nucleus) is at least partly controlled by the responses of the substrates themselves to a common set of signals

Kinetochore Attachments Require an Interaction between Unstructured Tails on Microtubules and Ndc80Hec1

SummaryKinetochore attachments to microtubules are tight enough to move chromosomes, yet the microtubules' plus ends must remain dynamic and reposition within the attachment pocket during depolymerization-coupled movement. Kinetochores are unable to bind microtubules after any of the four subunits of the Ndc80 complex are knocked down [2, 4]; however, because the Ndc80 complex has important structural roles [1–3], it is unclear whether it directly mediates kinetochore-microtubule attachments. The Ndc80Hec1 subunit (Hec1) has a microtubule-binding site composed of both an unstructured N-terminal tail and a calponin homology domain [5–7]. Here, we show that, surprisingly, the N-terminal tail is sufficient for microtubule-binding affinity in vitro. The interaction is salt sensitive, and the positively charged Hec1 tail cannot bind microtubules lacking negatively charged tails. We have replaced the endogenous Hec1 subunit with a mutant lacking the N-terminal tail. These cells assemble kinetochores properly but are unable to congress chromosomes, generate tension across sister kinetochores, or establish cold-stable kinetochore-microtubule attachments. Our data argue that the highest affinity interactions between kinetochores and microtubules are ionic attractions between two unstructured domains. We discuss the importance of this finding for models of repositioning of microtubules in the kinetochore during depolymerization

Attract, confuse, repel: Basics of visual perception and possibilities of optical manipulation of insect pests

Die optische Manipulation von Schadinsekten stellt mit weiteren präventiven Maßnahmen eine Grundlage für integrierte Systeme zum Pflanzenschutz dar. Mittels der Manipulation der visuellen Wahrnehmung wird Insekten das Auffinden ihrer Wirte erschwert und somit die Zuflugsrate gesenkt. Besonders bei Insekten mit hohen Reproduktionsraten kann aber schon der verminderte Befallszuflug einen großen Einfluss auf die Einhaltung späterer Schadschwellen haben. Die Grundlage hierfür liegt in der visuellen Ökologie von Insekten und ihrer visuellen Wahrnehmung und dem daraus folgenden Verhalten. Die aus dieser Wahrnehmung hervorgehenden Ansätze zur optischen Manipulation reichen von der Nutzung von Kontrasteffekten, über farbige Fallen, bis zur Verwendung von repellent wirkenden Materialien. Durch die Entwicklungen im Bereich Leuchtdioden ist es zudem möglich schmalbandiges Licht für die optische Manipulation zu nutzen. Aktuelle Methoden der optischen Manipulation und ihre Anwendungsmöglichkeiten werden anhand von Beispielen beschrieben.The optical manipulation of insect pests, together with other preventive measures, forms the basis for integrated crop protection systems. The manipulation of the visual perception makes it more difficult for insects to find their hosts and thus reduces the infestation rate. Particularly in the case of insects with high reproduction rates, the reduction in initial infestation can already be decisive for keeping below later damage thresholds. The basis for this lies in the visual ecology of insects and their visual perception and subsequent behaviour. The approaches to optical manipulation that emerge from this perception range from the use of contrast effects to coloured traps and the use of repellent materials. Developments in the field of light-emitting diodes have also made it possible to use narrow-band light for optical manipulation. Current methods of optical manipulation and their possible applications are described using examples