DUGGAN, STEPHEN. The Two Americas. Pp. xx, 277. New York: Charles Scribner's Sons, 1934. $1.75

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66691/2/10.1177_000271623417600174.pd

In vivo imaging of pyrrole-imidazole polyamides with positron emission tomography

The biodistribution profiles in mice of two pyrrole-imidazole polyamides were determined by PET. Pyrrole-imidazole polyamides are a class of small molecules that can be programmed to bind a broad repertoire of DNA sequences, disrupt transcription factor-DNA interfaces, and modulate gene expression pathways in cell culture experiments. The 18F-radiolabeled polyamides were prepared by oxime ligation between 4-[18F]-fluorobenzaldehyde and a hydroxylamine moiety at the polyamide C terminus. Small animal PET imaging of radiolabeled polyamides administered to mice revealed distinct differences in the biodistribution of a 5-ring β-linked polyamide versus an 8-ring hairpin, which exhibited better overall bioavailability. In vivo imaging of pyrrole-imidazole polyamides by PET is a minimum first step toward the translation of polyamide-based gene regulation from cell culture to small animal studies

Beyond Skills: An Integrative Approach to Doctoral Student Preparation for Diverse Careers

An early consensus in the ongoing discourse about graduate student preparation for diverse careers was that graduates lacked competencies relevant to non-academic professional settings. Lists of missing “skills” were developed that universities and agencies sought to address, most commonly by the offering of generic (transferable) skills workshops or courses. In this paper, we critique this framing of the issue and discuss the limitations of the common approaches taken to address it. We propose a more integrated approach, where students’ thesis research itself is oriented to their possible futures (a practice already occurring in many areas), and where assessment of the competencies so developed is integral to the awarding of the degree. We illustrate the concepts through the stories of two students, and discuss policy ramifications and the substantial challenges to its realization presented by a highly competitive research environment and established ways of assessing success in faculty and students.  Dans le débat toujours actuel à l’égard de la préparation des étudiants des études supérieures à leur entrée sur le marché du travail, le consensus qui s’en dégageait au départ était que les étudiants diplômés ne disposaient pas des compétences pertinentes aux milieux professionnels non universitaires. Devant ces conclusions, les universités et agences de placement ont cherché à combler ce «manque de compétences», surtout au moyen de cours et d’ateliers de compétences générales (transférables). Nous offrons ici une critique de cette façon de répondre au problème et nous discutons des limites des façons courantes de l’aborder. Nous proposons une approche plus intégrée pour perfectionner ces compétences, approche par laquelle la thèse de l’étudiant s’oriente précisément vers l’avenir vocationnel de celui-ci (une pratique déjà courante dans plusieurs domaines). L’évaluation des compétences ainsi développées devient indispensable à la remise du diplôme. Nous illustrons ces concepts par le truchement de deux études de cas. De manière plus générale, nous discutons des ramifications politiques potentielles de cette approche, ainsi que des défis importants liés à sa réalisation dans un milieu de recherche hautement concurrentiel, et mettons en pratique des moyens d’en évaluer la réussite.&nbsp

Gyrotron experiments employing a field emission array cathode

The design and operation of a field emission array (FEA) cathode and the subsequent demonstration of the first FEA gyrotron are presented. Up to 10 mA from 30 000 tips was achieved reproducibly from each of ten chips in a gyrotron environment, namely, a vacuum 1 x 10(-8) mbar, -50 kV potential with multiple chip operation, The design parameters of the FEA gun were similar to those of a magnetron injection gun with an achievable electron beam current of 50-100 mA and measured power 720 W cw. Coherent microwave radiation was detected in both TE(02) at 30.1 GHz and TE(03) at 43.6 GHz, with a starting current of 1 mA

Primary school teachers' use of digital resources with interactive whiteboards: The Australian context

As interactive whiteboards appear in increasing numbers in primary classrooms, questions will continue to be asked about the effectiveness of these devices in supporting teaching and learning. It is not the board itself, however, which is likely to make a difference to student learning outcomes, but the resources which teachers choose to use in conjunction with their board. This study investigated what digital resources Australian primary school teachers are using when teaching with interactive whiteboards and the factors affecting their choice of such resources. Data were collected from 116 teachers from 13 primary schools in regional and metropolitan areas via an online survey and follow-up focus groups. While flipchart software plays an important role in delivery of lessons, a broad range of resources, particularly online, interactive and multimedia resources are utilised. National, pedagogical and curriculum relevance are critical influences on Australian teachers' resource choice and word-of-mouth plays a dominant role in influencing patterns of use. There are important implications from the study for teachers, school leaders, teacher educators and producers of digital resources

On the structure of non-full-rank perfect codes

The Krotov combining construction of perfect 1-error-correcting binary codes from 2000 and a theorem of Heden saying that every non-full-rank perfect 1-error-correcting binary code can be constructed by this combining construction is generalized to the $q$-ary case. Simply, every non-full-rank perfect code $C$ is the union of a well-defined family of $\mu$-components $K_\mu$, where $\mu$ belongs to an "outer" perfect code $C^*$, and these components are at distance three from each other. Components from distinct codes can thus freely be combined to obtain new perfect codes. The Phelps general product construction of perfect binary code from 1984 is generalized to obtain $\mu$-components, and new lower bounds on the number of perfect 1-error-correcting $q$-ary codes are presented.Comment: 8 page

On the form of growing strings

Patterns and forms adopted by Nature, such as the shape of living cells, the geometry of shells and the branched structure of plants, are often the result of simple dynamical paradigms. Here we show that a growing self-interacting string attached to a tracking origin, modeled to resemble nascent polypeptides in vivo, develops helical structures which are more pronounced at the growing end. We also show that the dynamic growth ensemble shares several features of an equilibrium ensemble in which the growing end of the polymer is under an effective stretching force. A statistical analysis of native states of proteins shows that the signature of this non-equilibrium phenomenon has been fixed by evolution at the C-terminus, the growing end of a nascent protein. These findings suggest that a generic non-equilibrium growth process might have provided an additional evolutionary advantage for nascent proteins by favoring the preferential selection of helical structures.Comment: 4 pages, 3 figures. Accepted for publication in Phys. Rev. Let

Brahman Genetics Negatively Impact Protein Degradation and Tenderness of Longissimus Lumborum Steaks, but do Not Influence Collagen Cross-Linking

Beef tenderness is an important factor contributing to consumer eating satisfaction of beef products. Tenderness is dependent on several factors including: breed-type, postmortem age time, myofibrillar muscle protein degradation, and collagen content. During the past 30 years, numerous studies have indicated steaks from cattle with a greater percentage of Brahman genetics are tougher than steaks from Bos taurus cattle. The cause of tougher steaks is commonly attributed to Brahman cattle having a greater calpastatin activity which inhibits calpains, the enzymes responsible for myofibrillar protein degradation during the postmortem aging process. Some researchers have reported calpastatin activity was poorly correlated to tenderness of steaks from Brahman cattle. Others have reported sensory panelists indicated steaks from cattle with increasing percentages of Brahman genetics have an increase in the amount of connective tissue or collagen. Additionally, researchers have reported an increase in expression of genes that play a role in cross-linking of collagen which decreases collagen solubility. Due to these findings, we hypothesized steaks from cattle with greater Brahman genetics have more collagen cross-links and therefore a less soluble collagen fraction. The objective of this study was to evaluate the effect of Brahman genetics on protein degradation, collagen cross-linking, and meat tenderness of strip loin steaks

Numerical simulation of unconstrained cyclotron resonant maser emission

When a mainly rectilinear electron beam is subject to significant magnetic compression, conservation of magnetic moment results in the formation of a horseshoe shaped velocity distribution. It has been shown that such a distribution is unstable to cyclotron emission and may be responsible for the generation of Auroral Kilometric Radiation (AKR) an intense rf emission sourced at high altitudes in the terrestrial auroral magnetosphere. PiC code simulations have been undertaken to investigate the dynamics of the cyclotron emission process in the absence of cavity boundaries with particular consideration of the spatial growth rate, spectral output and rf conversion efficiency. Computations reveal that a well-defined cyclotron emission process occurs albeit with a low spatial growth rate compared to waveguide bounded simulations. The rf output is near perpendicular to the electron beam with a slight backward-wave character reflected in the spectral output with a well defined peak at 2.68GHz, just below the relativistic electron cyclotron frequency. The corresponding rf conversion efficiency of 1.1% is comparable to waveguide bounded simulations and consistent with the predictions of kinetic theory that suggest efficient, spectrally well defined radiation emission can be obtained from an electron horseshoe distribution in the absence of radiation boundaries.Publisher PD