Fermion propagators in space-time

The one- and the two-particle propagators for an infinite non-interacting Fermi system are studied as functions of space-time coordinates. Their behaviour at the origin and in the asymptotic region is discussed, as is their scaling in the Fermi momentum. Both propagators are shown to have a divergence at equal times. The impact of the interaction among the fermions on their momentum distribution, on their pair correlation function and, hence, on the Coulomb sum rule is explored using a phenomenological model. Finally the problem of how the confinement is reflected in the momentum distribution of the system's constituents is briefly addressed.Comment: 26 pages, 9 figures, accepted for publication on Phys. Rev.

Connecting scaling with short-range correlations

We reexamine several issues related to the physics of scaling in electron scattering from nuclei. A basic model is presented in which an assumed form for the momentum distribution having both long- and short-range contributions is incorporated in the single-particle Green function. From this one can obtain saturation of nuclear matter for an NN interaction with medium-range attraction and short-range repulsion, and can obtain the density-density polarization propagator and hence the electromagnetic response and scaling function. For the latter, the shape of the scaling function and how it approaches scaling as a function of momentum transfer are both explored.Comment: 24 pages, 15 figures. A reference has been corrected and update

Re-Envisioning ESL for Short-Term Programs

ESL professionals have traditionally taught the four language skills, vocabulary, and grammar in Intensive English Programs (IEPs) to help incoming students satisfy the university’s ESL requirement. As international education continues to change, however, the ESL profession will need to re-conceptualize its role and make explicit its evolving relevance. IEPs and traditional ESL classes are not necessarily applicable to short-term programs, whose purpose is to give participants some experience at a US institution with a focus on a specific discipline or area of study.  This paper demonstrates two ways ESL professionals re-envisioned their role at the university for short-term programs (STPs) by creating English courses for the international education experience. With linguistic and cultural guidance from the ESL instructors, participants in these English courses critically analyzed impactful observations, perceptions, ideas, or events from the STP and gave PowerPoint presentations at a program-wide conference on their analysis of one academic or non-academic concept or observation that had the most impact

Severe axonal neuropathy is a late manifestation of SPG11

Complex hereditary spastic paraplegia (HSP) is a clinically heterogeneous group of disorders usually inherited in an autosomal recessive manner. In the past, complex recessive spastic paraplegias have been frequently associated with SPG11 mutations but also with defects in SPG15, SPG7 and a handful of other rare genes. Pleiotropy exists in HSP genes, exemplified in the recent association of SPG11 mutations with CMT2. In this study, we performed whole exome sequence analysis and identified two siblings with novel compound heterozygous frameshift SPG11 mutations. The mutations segregated with disease were not present in control databases and analysis of skin fibroblast derived mRNA indicated that the SPG11 truncated mRNA species were not degraded significantly by non-sense mediated mRNA decay. These siblings had severe early-onset spastic paraplegia but later in their disease developed severe axonal neuropathy, neuropathic pain and blue/black foot discolouration likely caused by a combination of the severe neuropathy with autonomic dysfunction and peripheral oedema. We also identified a similar late-onset axonal neuropathy in a Cypriot SPG11 family. Although neuropathy is occasionally present in SPG11, in our SPG11 patients reported here it was particularly severe, highlighting the association of axonal neuropathy with SPG11 and the late manifestation of axonal peripheral nerve damage

A TESS Dress Rehearsal: Planetary Candidates and Variables from K2 Campaign 17T

We produce light curves for all ∼34,000 targets observed with K2 in Campaign 17 (C17), identifying 34 planet candidates, 184 eclipsing binaries, and other 222 periodic variables. The forward-facing direction of the C17 field means follow-up can begin immediately now that the campaign has concluded and interesting targets have been identified. The C17 field has a large overlap with C6, so this latest campaign also offers an infrequent opportunity to study a large number of targets already observed in a previous K2 campaign. The timing of the C17 data release, shortly before science operations begin with the Transiting Exoplanet Survey Satellite (TESS), also lets us exercise some of the tools and methods developed for identification and dissemination of planet candidates from TESS. We find excellent agreement between these results and those identified using only K2-based tools. Among our planet candidates are several planet candidates with sizes <4 R[subscript ⊕] and orbiting stars with Kp ≲ 10 (indicating good RV targets of the sort TESS hopes to find) and a Jupiter-sized single-transit event around a star already hosting a 6 day planet candidate. Key words: methods, data analysis, planets and satellites, detection – techniques, photometricUnited States. National Aeronautics and Space Administration (K2GO Grant 80NSSC18K0308

Choosing an E-Portfolio Tool

The presenters weigh the strengths and weaknesses of multiple e-portfolio applications to assist educators in choosing the proper system for their institution. E-Portfolios discussed include Chalk and Wire, FolioTek, Epsilen, Passport, and Sharepoint