TEACHING ACCOUNTING APPRECIATION AT THE BRITISH MUSEUM AND IN YOUR CLASSROOM

Every year the University of Mississippi offers an accountancy study abroad class in London, England. The title of the graduate-level class is “The Development of Accounting Thought.” The class is intended to help the students think about how accounting started as a discipline and about accounting’s contributions to society. One of the highlights of that trip is the visit to the British Museum to examine the cuneiform documents. This visit to the British Museum and the cuneiform exhibit serves to focus the students’ attention on accountancy’s contributions to the ancient world and to modern society

Structure of a monomeric photosystem II core complex from a cyanobacterium acclimated to far-red light reveals the functions of chlorophylls d and f

Far-red light (FRL) photoacclimation in cyanobacteria provides a selective growth advantage for some terrestrial cyanobacteria by expanding the range of photosynthetically active radiation to include far-red/near-infrared light (700-800 nm). During this photoacclimation process, photosystem II (PSII), the water:plastoquinone photooxidoreductase involved in oxygenic photosynthesis, is modified. The resulting FRL-PSII is comprised of FRL-specific core subunits and binds chlorophyll (Chl) d and Chl f molecules in place of several of the Chl a molecules found when cells are grown in visible light. These new Chls effectively lower the energy canonically thought to define the red limit for light required to drive photochemical catalysis of water oxidation. Changes to the architecture of FRL-PSII were previously unknown, and the positions of Chl d and Chl f molecules had only been proposed from indirect evidence. Here, we describe the 2.25 angstrom resolution cryo-EM structure of a monomeric FRL-PSII core complex from Synechococcus sp. PCC 7335 cells that were acclimated to FRL. We identify one Chl d molecule in the Chl(D1) position of the electron transfer chain and four Chl f molecules in the core antenna. We also make observations that enhance our understanding of PSII biogenesis, especially on the acceptor side of the complex where a bicarbonate molecule is replaced by a glutamate side chain in the absence of the assembly factor Psb28. In conclusion, these results provide a structural basis for the lower energy limit required to drive water oxidation, which is the gateway for most solar energy utilization on earth

Low-Temperatures Vortex Dynamics in Twinned Superconductors

We discuss the low-temperature dynamics of magnetic flux lines in samples with a family of parallel twin planes. A current applied along the twin planes drives flux motion in the direction transverse to the planes and acts like an electric field applied to {\it one-dimensional} carriers in disordered semiconductors. As in flux arrays with columnar pins, there is a regime where the dynamics is dominated by superkink excitations that correspond to Mott variable range hopping (VRH) of carriers. In one dimension, however, rare events, such as large regions void of twin planes, can impede VRH and dominate transport in samples that are sufficiently long in the direction of flux motion. In short samples rare regions can be responsible for mesoscopic effects.Comment: 4 pages, 2 figures email: [email protected]

Visual control of refuge recognition in the whip spider \u3ci\u3ePhrynus marginemaculatus\u3c/i\u3e

Amblypygids, or whip spiders, are nocturnally active arachnids which live in structurally complex environments. Whip spiders are excellent navigators that can re-locate a home refuge without relying on visual input. Therefore, an open question is whether visual input can control any aspect of whip spider spatial behavior. In the current study, Phrynus marginemaculatus were trained to locate an escape refuge by discriminating between differently oriented black and white stripes placed either on the walls of a testing arena (frontal discrimination) or on the ceiling of the same testing arena (overhead discrimination). Regardless of the placement of the visual stimuli, the whip spiders were successful in learning the location of the escape refuge. In a follow-up study of the overhead discrimination, occluding the median eyes was found to disrupt the ability of the whip spiders to locate the shelter. The data support the conclusion that whip spiders can rely on vision to learn and recognize an escape shelter. We suggest that visual inputs to the brain’s mushroom bodies enable this ability

Structure of a dimeric photosystem II complex from a cyanobacterium acclimated to far-red light

Photosystem II (PSII) is the water-splitting enzyme central to oxygenic photosynthesis. To drive water oxidation, light is harvested by accessory pigments, mostly chlorophyll (Chl) a molecules, which absorb visible light (400–700 nm). Some cyanobacteria facultatively acclimate to shaded environments by altering their photosynthetic machinery to additionally absorb far-red light (FRL, 700–800 nm), a process termed far-red light photoacclimation or FaRLiP. During far-red light photoacclimation, FRL-PSII is assembled with FRL-specific isoforms of the subunits PsbA, PsbB, PsbC, PsbD, and PsbH, and some Chl-binding sites contain Chls d or f instead of the usual Chl a. The structure of an apo-FRL-PSII monomer lacking the FRL-specific PsbH subunit has previously been determined, but visualization of the dimeric complex has remained elusive. Here, we report the cryo-EM structure of a dimeric FRL–PSII complex. The site assignments for Chls d and f are consistent with those assigned in the previous apo-FRL-PSII monomeric structure. All sites that bind Chl d or Chl f at high occupancy exhibit a FRL-specific interaction of the formyl moiety of the Chl d or Chl f with the protein environment, which in some cases involves a phenylalanine sidechain. The structure retains the FRL-specific PsbH2 subunit, which appears to alter the energetic landscape of FRL-PSII, redirecting energy transfer from the phycobiliprotein complex to a Chl f molecule bound by PsbB2 that acts as a bridge for energy transfer to the electron transfer chain. Collectively, these observations extend our previous understanding of the structure-function relationship that allows PSII to function using lower energy FRL

A Review of Basic Energy Reconstruction Techniques in Liquid Xenon and Argon Detectors for Dark Matter and Neutrino Physics Using NEST

Detectors based upon the noble elements, especially liquid xenon as well as liquid argon, as both single- and dual-phase types, require reconstruction of the energies of interacting particles, both in the field of direct detection of dark matter (Weakly Interacting Massive Particles or WIMPs, axions, etc.) and in neutrino physics. Experimentalists, as well as theorists who reanalyze/reinterpret experimental data, have used a few different techniques over the past few decades. In this paper, we review techniques based on solely the primary scintillation channel, the ionization or secondary channel available at non-zero drift electric fields, and combined techniques that include a simple linear combination and weighted averages, with a brief discussion of the applications of profile likelihood, maximum likelihood, and machine learning. Comparing results for electron recoils (beta and gamma interactions) and nuclear recoils (primarily from neutrons) from the Noble Element Simulation Technique (NEST) simulation to available data, we confirm that combining all available information generates higher-precision means, lower widths (energy resolution), and more symmetric shapes (approximately Gaussian) especially at keV-scale energies, with the symmetry even greater when thresholding is addressed. Near thresholds, bias from upward fluctuations matters. For MeV-GeV scales, if only one channel is utilized, an ionization-only-based energy scale outperforms scintillation; channel combination remains beneficial. We discuss here what major collaborations use.Comment: 42 Pages, 2 Tables, 11 Figures, 13 Equation

Problems With the Vortex-Boson Mapping in 1+1 Dimensions

Using the well known boson mapping, we relate the transverse magnetic susceptibility of a system of flux vortices in 1+1 dimensions to an appropriately defined conductivity of a one-dimensional boson system. The tilt response for a system free of disorder is calculated directly, and it is found that a subtle order of limits is required to avoid deceptive results.Comment: 4 Pages (REVTeX 3.0). Postscript file for this paper is available on the World Wide Web at http://cmtw.harvard.edu/~simon/

Adult North Star Network (ANSN): Consensus Document for Therapists Working with Adults with Duchenne Muscular Dystrophy (DMD) - Therapy Guidelines

BACKGROUND The survival of people with Duchenne Muscular Dystrophy (DMD) significantly increased due to improvements in standards of care (SOC) [1]. Consequently, DMD has evolved from a paediatric disease to a severe, chronic, multisystem, adult condition. The published international standards of care advocate specialist multidisciplinary health monitoring through proactive, anticipatory approaches to slow down the effects of the disease and allow advanced, informed decision-making [1–3]. Therapy starts as soon as the diagnosis is made and plays a vital role in symptom management in individuals to improve function, participation and effective quality of life. Therapy interventions for management, differ depending on the setting in which the care is being provided, specifically in terms of the expertise within the teams and resources available within these settings. People with DMD find that when they transition to adult services there is a dearth of expertise and limited access to therapy services. The survey conducted in the UK highlighted substantial differences between the care received by adults and children with the condition [2]. A large proportion of adults with DMD reported increased difficulties with access to professional physiotherapy, particularly at transition from childhood to adulthood. Additionally, having their functional abilities assessed regularly or receiving professional physiotherapy in general were both significantly more difficult to achieve within adult services in the UK. Furthermore, some of the major problems expressed by adults with DMD were mobility and transportation as well as, getting involved in leisure activities and work [3]. Therefore, while pediatric services are predominantly family-centred, after transition the paradigm of patient care changes towards individual-centred with focus on different therapy goals. Those become more tailored to the individuals’ needs, balancing quality of life and management options.This document is aimed at providing guidelines for physiotherapy, occupational therapy and speech and language considerations. The ‘Adult North Star Network’ (ANSN) was founded in 2015 to advance care of adults with DMD living in the UK and to develop a prospective natural history database. There are currently 28 adult centres within the network, caring for at least 700 DMD patients. Transition age is varied depending on services and is generally between the ages of 16 to 18. There is a wide range of severity affecting people with DMD transitioned to adult services, those who are steroid naive will have been permanent wheelchair users for many years and have profound muscle weakness. On the other hand, steroid treated patients will most commonly have good upper limb function, and some maybe ambulant at the time of transition. Additionally the specific type of genetic mutation, compliance to therapy and environmental factors may play a role in disease progression and presentation at transition. The aim of these guidelines is to support therapists working with adults with DMD with little or no experience to assist their clinical practice. Whilst the recommendations can be adopted by other health care systems in the world, we appreciate it will depend on resource availability