Shared Leadership: A Unique but Beneficial Arrangement within a University Department

Universities often lose some of their best teachers and researchers to transitions to administration. Conversely, the ability of universities to persuade some faculty to assume administrative duties is undermined due to faculty members’ reluctance to give up teaching or research. In this article, two faculty members who currently serve as co-department heads discuss (a) their motivation for pursuing such an arrangement, (b) the way in which their duties are divided and shared, (c) challenges in pursuing the co-head arrangement, (d) challenges in implementing the co-head arrangement, (e) their perceptions of the success of the arrangement, and (f) significant considerations for those who may be interested in pursuing a similar arrangement

Restoration and Monitoring of the River Otter Population in Iowa

Northern river otters (Lontra canadensis) were widespread in North America at the time of European settlement. However, river otters were extirpated from most of Iowa in the early 1900s due to habitat degradation and unregulated harvest. In 1985, the Iowa Department of Natural Resources began an effort to restore the river otter population throughout the state, including a pilot study of survival to determine if establishment was feasible. Annual survival was estimated to be 86% during the pilot study. River otters dispersed an average of about 11 km from the point of release and exhibited habitat use typical for the species. Based on the successful pilot study, 261 river otters were released in the state of Iowa from 1986-2001. More recently we examined the age structure and reproductive effort of 81 river otters (43 females and 38 males) collected in Iowa from 1999-2001 to document the characteristics of the reestablished population. We found that 41% of the otters sampled were juveniles, 38% were yearlings and 21% were adults. Fifty-five percent of all female otters were pregnant, and 80% of adult females were pregnant. We observed a mean of 2.9 corpora lutea/female and calculated that female’s ≥ 1 year old could potentially produce an average 5.7 female offspring during an average life span. Based on the widespread distribution, healthy reproductive characteristics, and high survival rates it is feasible that a limited harvest of river otter could be implemented in Iowa

Evidence for a Single-Spin Azimuthal Asymmetry in Semi-inclusive Pion Electroproduction

Single-spin asymmetries for semi-inclusive pion production in deep-inelastic scattering have been measured for the first time. A significant target-spin asymmetry of the distribution in the azimuthal angle φ of the pion relative to the lepton scattering plane was formed for π^+ electroproduction on a longitudinally polarized hydrogen target. The corresponding analyzing power in the sinφ moment of the cross section is 0.022±0.005±0.003. This result can be interpreted as the effect of terms in the cross section involving chiral-odd spin distribution functions in combination with a chiral-odd fragmentation function that is sensitive to the transverse polarization of the fragmenting quark

Polyphony: superposition independent methods for ensemble-based drug discovery.

BACKGROUND: Structure-based drug design is an iterative process, following cycles of structural biology, computer-aided design, synthetic chemistry and bioassay. In favorable circumstances, this process can lead to the structures of hundreds of protein-ligand crystal structures. In addition, molecular dynamics simulations are increasingly being used to further explore the conformational landscape of these complexes. Currently, methods capable of the analysis of ensembles of crystal structures and MD trajectories are limited and usually rely upon least squares superposition of coordinates. RESULTS: Novel methodologies are described for the analysis of multiple structures of a protein. Statistical approaches that rely upon residue equivalence, but not superposition, are developed. Tasks that can be performed include the identification of hinge regions, allosteric conformational changes and transient binding sites. The approaches are tested on crystal structures of CDK2 and other CMGC protein kinases and a simulation of p38α. Known interaction - conformational change relationships are highlighted but also new ones are revealed. A transient but druggable allosteric pocket in CDK2 is predicted to occur under the CMGC insert. Furthermore, an evolutionarily-conserved conformational link from the location of this pocket, via the αEF-αF loop, to phosphorylation sites on the activation loop is discovered. CONCLUSIONS: New methodologies are described and validated for the superimposition independent conformational analysis of large collections of structures or simulation snapshots of the same protein. The methodologies are encoded in a Python package called Polyphony, which is released as open source to accompany this paper [http://wrpitt.bitbucket.org/polyphony/]

A High Power Hydrogen Target for Parity Violation Experiments

Parity-violating electron scattering measurements on hydrogen and deuterium, such as those underway at the Bates and CEBAF laboratories, require luminosities exceeding $10^{38}$cm$^{-2}$s$^{-1}$, resulting in large beam power deposition into cryogenic liquid. Such targets must be able to absorb 500 watts or more with minimal change in target density. A 40~cm long liquid hydrogen target, designed to absorb 500~watts of beam power without boiling, has been developed for the SAMPLE experiment at Bates. In recent tests with 40~$\mu$A of incident beam, no evidence was seen for density fluctuations in the target, at a sensitivity level of better than 1\%. A summary of the target design and operational experience will be presented.Comment: 13 pages, 9 postscript figure

The Strange Quark Contribution to the Proton's Magnetic Moment

We report a new determination of the strange quark contribution to the proton's magnetic form factor at a four-momentum transfer Q2 = 0.1 (GeV/c)^2 from parity-violating e-p elastic scattering. The result uses a revised analysis of data from the SAMPLE experiment which was carried out at the MIT-Bates Laboratory. The data are combined with a calculation of the proton's axial form factor GAe to determine the strange form factor GMs(Q2=0.1)=0.37 +- 0.20 +- 0.26 +- 0.07. The extrapolation of GMs to its Q2=0 limit and comparison with calculations is also discussed.Comment: 6 pages, 1 figure, submitted to Phys. Lett.

Determination of the Axial-Vector Weak Coupling Constant with Ultracold Neutrons

A precise measurement of the neutron decay $\beta$-asymmetry $A_0$ has been carried out using polarized ultracold neutrons (UCN) from the pulsed spallation UCN source at the Los Alamos Neutron Science Center (LANSCE). Combining data obtained in 2008 and 2009, we report $A_0 = -0.11966 \pm 0.00089_{-0.00140}^{+0.00123}$, from which we determine the ratio of the axial-vector to vector weak coupling of the nucleon $g_A/g_V = -1.27590_{-0.00445}^{+0.00409}$.Comment: 5 pages, 2 figure