The Bee, A Natural History, by Noah Wilson-Rich (2014, Princeton University Press. ISBN: 9780691161358. US$27.95)

(excerpt) Upon receiving “The Bee, A Natural History”, by Noah Wilson Rich, I was drawn in by the title and the beautiful rust and grey front cover featuring a nearly 3-D photo of a honey bee. I immediately felt twinges of excitement—this is the book I have always wanted to have available for my university course, Apiculture and Honey Bee Biology—and disappointment—I did not write it! The “bee”— singular—accompanied by the high-resolution photo, suggested that this book focused on the world’s best understood insect that my course is centered around, Apis mellifera

Specific fluorescent labeling of chicken myofibril Z-line proteins catalyzed by guinea pig liver transglutaminase

Guinea pig liver transglutaminase has been found to catalyze the covalent incorporation of dansylcadaverine into chicken skeletal muscle myofibril proteins. Epifluorescence microscopy reveals that the incorporated dansylcadaverine is specifically localized at or near the myofibril Z line. SDS-polyacrylamide gel electrophoresis (SDS-PAGE) indicates that actin constitutes a major fraction of the labeled material; the Z-line proteins alpha-actinin and desmin also show significant labeling, as well as tropomyosin, several additional unidentified proteins, and material with an extremely high molecular weight. The Z-line-specific fluorescence can be removed by brief trypsinization, which releases fluorescent alpha-actinin into the supernate. The majority of the fluorescent protein species are resistant to extraction by either 0.6 M KCl or KI. These results, in conjunction with the microscopic localization, suggest that the dansyl- labeled proteins are constituents of the myofibril Z line. A significant amount of fluorescently labeled transglutaminase is also present in labeled myofibrils, which is resistant to extraction with either 0.6 M KCl or KI. This result indicates a strong, noncovalent interaction between the transglutaminase molecule and the myofibril Z line

Approximating Persistent Homology in Euclidean Space Through Collapses

The \v{C}ech complex is one of the most widely used tools in applied algebraic topology. Unfortunately, due to the inclusive nature of the \v{C}ech filtration, the number of simplices grows exponentially in the number of input points. A practical consequence is that computations may have to terminate at smaller scales than what the application calls for. In this paper we propose two methods to approximate the \v{C}ech persistence module. Both are constructed on the level of spaces, i.e. as sequences of simplicial complexes induced by nerves. We also show how the bottleneck distance between such persistence modules can be understood by how tightly they are sandwiched on the level of spaces. In turn, this implies the correctness of our approximation methods. Finally, we implement our methods and apply them to some example point clouds in Euclidean space

Topological exploration of artificial neuronal network dynamics

One of the paramount challenges in neuroscience is to understand the dynamics of individual neurons and how they give rise to network dynamics when interconnected. Historically, researchers have resorted to graph theory, statistics, and statistical mechanics to describe the spatiotemporal structure of such network dynamics. Our novel approach employs tools from algebraic topology to characterize the global properties of network structure and dynamics. We propose a method based on persistent homology to automatically classify network dynamics using topological features of spaces built from various spike-train distances. We investigate the efficacy of our method by simulating activity in three small artificial neural networks with different sets of parameters, giving rise to dynamics that can be classified into four regimes. We then compute three measures of spike train similarity and use persistent homology to extract topological features that are fundamentally different from those used in traditional methods. Our results show that a machine learning classifier trained on these features can accurately predict the regime of the network it was trained on and also generalize to other networks that were not presented during training. Moreover, we demonstrate that using features extracted from multiple spike-train distances systematically improves the performance of our method

The Robert E. Gard Reader : To Change the Face of America, From Writings by Robert E. Gard

This Reader draws from the works of Robert E. Gard, professor at the University of Wisconsin, Extension. His chief areas of activity were in the theatre arts and in creative writing, with a strong side activity in collecting and publishing the folklore of the state. He established the functional area of arts development under University Extension and remained a specialist in the arts in smaller communities and rural areas.https://engagedscholarship.csuohio.edu/scholbks/1000/thumbnail.jp

Aging and Work in Canada: Firm Policies

Few Canadian firms have explicit policies dealing with the aging of their workforces, other than pension policies geared to a conventional retirement age. However, other firm policies have unanticipated consequences that apply differentially to older and younger workers. This paper reviews several relevant firm practices used in Canada, including pension and benefits practices, training policies and programs, and work and family practices. The most dramatic firm practice that has an impact on the older worker is restructuring through downsizing the workforce by means of retirement incentives and layoffs. We introduce the issue by considering available national-level Canadian data, and then consider five case studies representing different configurations of firm practices. These cases are: Sun Life Assurance Company of Canada, NOVA Corporation, Slater Steels, Bell Canada, and the garment industry in Montreal. Both management and employee level data are presented. We argue the importance of organizational latitude in establishing firm-based policies that dramatically change the nature of the life course in Canada.aging workforce; firm policies