Attract and deter: a dual role for pyrrolizidine alkaloids in plant–insect interactions

Pyrrolizidine alkaloids (PAs) are the major defense compounds of plants in the Senecio genus. Here I will review the effects of PAs in Senecio on the preference and performance of specialist and generalist insect herbivores. Specialist herbivores have evolved adaptation to PAs in their host plant. They can use the alkaloids as cue to find their host plant and often they sequester PAs for their own defense against predators. Generalists, on the other hand, can be deterred by PAs. PAs can also affect survival of generalist herbivores. Usually generalist insects avoid feeding on young Senecio leaves, which contain a high concentration of alkaloids. Structurally related PAs can differ in their effects on insect herbivores, some are more toxic than others. The differences in effects of PAs on specialist and generalists could lead to opposing selection on PAs, which may maintain the genetic diversity in PA concentration and composition in Senecio species

Analysis of Alternative Keyboards Using Learning Curves

Objective : To quantify learning percentages for alternative keyboards (chord, contoured split, Dvorak, and split fixed angle) and understand how physical, cognitive, and perceptual demand affect learning. Background: Alternative keyboards have been shown to offer ergonomic benefits over the conventional, single-plane QWERTY keyboard design, but productivity-related challenges may hinder their widespread acceptance. Method: Sixteen participants repeatedly typed a standard text passage using each alternative keyboard. Completion times were collected and subsequent learning percentages were calculated. Participants were asked to subjectively rate the physical, cognitive, and perceptual demands of each keyboard, and these values were then related to the calculated learning percentages. Results: Learning percentage calculations revealed the percentage for the split fixed-angle keyboard (90.4%) to be significantly different ( p Conclusions:Productivity decrements can be quickly regained for the split fixed-angle and contour split keyboard but will take considerably longer for Dvorak and chord keyboards. The split fixed-angle keyboard involved physical learning, whereas the others involved some combination of physical and cognitive learning, a result supported by the subjective responses. Application:Understanding the changes in task performance time that come with learning can provide additional information for a cost-benefit analysis when considering the implementation of ergonomic interventions.This is a manuscript of an article published as Anderson, Allison M., Gary A. Mirka, Sharon MB Joines, and David B. Kaber. "Analysis of alternative keyboards using learning curves." Human factors 51, no. 1 (2009): 35-45. doi: 10.1177/0018720808329844. Posted with permission.</p

Pathology Case Study: Left Breast Mass

This is a case study presented by the University of Pittsburgh Department of Pathology in which an 80-year-old woman presents to the hospital with &quot;a single, palpable, irregular mass in the left breast.&quot; Visitors are given the gross and microscopic descriptions, including images, and are given the opportunity to diagnose the patient. This is an excellent resource for students in the health sciences to familiarize themselves with using patient history and laboratory results to diagnose disease. It is also a helpful site for educators to use to introduce or test student learning in gynecologic pathology

Pathology Case Study: Skin Lesion

This is a case study presented by the University of Pittsburgh Department of Pathology in which a woman with uterine endometrioid adenocarcinoma with focal squamous differentiation arising in complex atypical hyperplasia. Visitors are given both the microscopic and gross descriptions, including images, and are given the opportunity to diagnose the patient. This is an excellent resource for students in the health sciences to familiarize themselves with using patient history and laboratory results to diagnose disease. It is also a helpful site for educators to use to introduce or test student learning in dermatologic pathology

Unusual Ovarian Stromal Tumor with Radiation Changes Mimicking Carcinoma

<p>Radiation-related changes including fibrosis, nuclear enlargement, hyperchromasia and cytoplasmic vacuolization may alter the appearance of normal ovarian tissue and ovarian tumors. We describe radiation-related changes in ovarian stromal neoplasm with mixed features of sclerosing stromal tumor and fibrothecoma. The right ovarian mass was discovered in a 38 year-old woman with past history of invasive squamous cell carcinoma of the cervix treated with cone biopsy and brachytherapy. The low power architecture of cellular pseudolobules and small sheets of tumor cells with scattered hyaline plaques was consisted with the pattern of combined sclerosing stromal tumor and fibrothecoma. However, the presence of severe cytologic atypia, as well as clear cell and signet ring differentiation and arrangements of tumor cells in single files and nests, raised a possibility of primary or metastatic carcinoma. The tumor cells were positive for calretinin, vimentin, inhibin, and WT1 and negative for AE1/3, cytokeratin 7 and 20, CD99, estrogen and progesterone receptors, mammaglobin, chromogranin, and S100 protein. Based on the results of immunostains and a subsequently provided history of radiation, a diagnosis of sex cord stromal tumor with mixed fibrothecoma and sclerosing stromal differentiation was made. Radiation-related atypia and fibrosis in sex cord stromal tumor may create a pattern mimicking carcinoma and therefore, in the presence of unusual histology, the use of immunohistochemistry is recommended.</p

Absent cadences

The slow movement of Symphony No. 64 in A major, ‘Tempora mutantur’, has long intrigued Haydn scholars on account of its absent cadences and enigmatic form. The Latin title of the symphony is thought to be derived from the epigram by John Owen, a near-contemporary of Shakespeare, and it was used by Elaine Sisman to support her hypothesis that the slow movement formed part of Haydn’s incidental music for Shakespeare’s Hamlet. The enigma can be explained through an analysis informed by concepts native to eighteenth-century music theory. The absent cadences create instances of ellipsis, a rhetorical figure described by Johann Adolph Scheibe and Johann Nikolaus Forkel, and the form plays with a familiar template codified by Heinrich Christoph Koch. This analysis leads to a different interpretation. Rather than suggesting the protagonist of Shakespeare’s tragedy, the movement stages a fictive composer in an act of musical comedy not dissimilar to that in Symphony No. 60, ‘Il Distratto’. The title comes not from Owen but from a Latin adage that was incorporated by Owen into his epigram. This adage had been popular in Germany since the Reformation and was then applied by one eighteenth-century music theorist to describe changes of musical conventions

Papillary Squamous Cell Carcinoma of the Vagina

This regular feature presents special issues in oncologic pathology