News from the Wilson Center

The Wilson Center is an independent, progressive religious & spiritual voice on campus

News from the Wilson Center

The Wilson Center is an independent, progressive religious & spiritual voice on campus

News from the Wilson Center

The Wilson Center is an independent, progressive religious & spiritual voice on campus

News from the Wilson Center

The Wilson Center is an independent, progressive religious & spiritual voice on campus

A new approach to generating research-quality phenology data: The USA National Phenology Monitoring System

The USA National Phenology Network (www.usanpn.org) has recently initiated a national effort to encourage people at different levels of expertise—from backyard naturalists to professional scientists—to observe phenology and contribute to a national database that will be used to greatly improve our understanding of spatio-temporal variation in phenology and associated phenological responses to climate change. Many phenological observation protocols identify specific single dates at which individual phenological events are observed, but the scientific usefulness of long-term phenological observations can be improved with a more carefully structured protocol. At the USA-NPN we have developed a new approach that directs observers to record each day that they observe an individual plant, and to assess and report the state of specific life stages (or phenophases) as occurring or not occurring on that plant for each observation date. Observations of animal phenophases are similarly recorded, although for a species as a whole rather than for a specific individual. Evaluation is phrased in terms of simple, easy-to-understand, questions (e.g. “Do you see open flowers?”) which makes it appropriate for a broad audience. From this method, a rich dataset of phenological metrics can be extracted, including the duration of a phenophase (e.g. open flowers), the beginning and end points of a phenophase (e.g. traditional phenological events such as first flower and end flowering), multiple distinct occurrences of phenophases within a single growing season (e.g multiple flowering events, common in drought-prone regions), as well as quantification of sampling frequency and observational uncertainties. The system also includes a mechanism for translation of phenophase start and end points into standard traditional phenological events to facilitate comparison of contemporary data collected with this new “phenophase status” monitoring approach to historical datasets collected with the “phenological event” monitoring approach. These features greatly enhance the utility of the resulting data for statistical analyses addressing questions such as how phenological events vary in time and space, and in response to global change

FIR/submm spectroscopy with Herschel: first results from the VNGS and H-ATLAS surveys

The FIR/submm window is one of the least-studied regions of the electromagnetic spectrum, yet this wavelength range is absolutely crucial for understanding the physical processes and properties of the ISM in galaxies. The advent of the Herschel Space Observatory has opened up the entire FIR/submm window for spectroscopic studies. We present the first FIR/submm spectroscopic results on both nearby and distant galaxies obtained in the frame of two Herschel key programs: the Very Nearby Galaxies Survey and the Herschel ATLAS

Understanding and Teaching Holocaust Education Authors : Paula Cowan & Henry Maitles London: Sage Publications (2017) pp. 120 Paperback £20.00 ISBN 978-1473919341

Peer reviewedPublisher PD

Rationale for UV-filtered clover fermions

We study the contributions Sigma_0 and Sigma_1, proportional to a^0 and a^1, to the fermion self-energy in Wilson's formulation of lattice QCD with UV-filtering in the fermion action. We derive results for m_{crit} and the renormalization factors Z_S, Z_P, Z_V, Z_A to 1-loop order in perturbation theory for several filtering recipes (APE, HYP, EXP, HEX), both with and without a clover term. The perturbative series is much better behaved with filtering, in particular tadpole resummation proves irrelevant. Our non-perturbative data for m_{crit} and Z_A/(Z_m*Z_P) show that the combination of filtering and clover improvement efficiently reduces the amount of chiral symmetry breaking -- we find residual masses am_{res}=O(10^{-2}).Comment: 25 pages, 4 figures; v2: typo in eqn. (37) fixed [agrees with published version

Dynamically-coupled partial-waves in ρπ\rho\pi isospin-2 scattering from lattice QCD

We present the first determination of $\rho \pi$ scattering, incorporating dynamically-coupled partial-waves, using lattice QCD, a first-principles numerical approach to QCD. Considering the case of isospin-2 $\rho \pi$, we calculate partial-wave amplitudes with $J \le 3$ and determine the degree of dynamical mixing between the coupled $S$ and $D$-wave channels with $J^P=1^+$. The analysis makes use of the relationship between scattering amplitudes and the discrete spectrum of states in the finite volume lattice. Constraints on the scattering amplitudes are provided by over one hundred energy levels computed on two lattice volumes at various overall momenta and in several irreducible representations of the relevant symmetry groups. The spectra follow from variational analyses of matrices of correlations functions computed with large bases of meson-meson operators. Calculations are performed with degenerate light and strange quarks tuned to the physical strange quark mass so that $m_\pi \sim 700$ MeV, ensuring that the $\rho$ is stable against strong decay. This work demonstrates the successful application of techniques, opening the door to calculations of scattering processes that incorporate the effects of dynamically-coupled partial-waves, including those involving resonances or bound states.Comment: Minor changes to match the published versio