First Time-dependent Study of H2 and H3+ Ortho-Para Chemistry in the Diffuse Interstellar Medium: Observations Meet Theoretical Predictions

The chemistry in the diffuse interstellar medium initiates the gradual increase of molecular complexity during the life cycle of matter. A key molecule that enables build-up of new molecular bonds and new molecules via proton-donation is H3+. Its evolution is tightly related to molecular hydrogen and thought to be well understood. However, recent observations of ortho and para lines of H2 and H3+ in the diffuse ISM showed a puzzling discrepancy in nuclear spin excitation temperatures and populations between these two key species. H3+, unlike H2, seems to be out of thermal equilibrium, contrary to the predictions of modern astrochemical models. We conduct the first time-dependent modeling of the para-fractions of H2 and H3+ in the diffuse ISM and compare our results to a set of line-of-sight observations, including new measurements presented in this study. We isolate a set of key reactions for H3+ and find that the destruction of the lowest rotational states of H3+ by dissociative recombination largely control its ortho/para ratio. A plausible agreement with observations cannot be achieved unless a ratio larger than 1:5 for the destruction of (1,1)- and (1,0)-states of H3+ is assumed. Additionally, an increased CR ionization rate to 10(-15) 1/s further improves the fit whereas variations of other individual physical parameters, such as density and chemical age, have only a minor effect on the predicted ortho/para ratios. Thus our study calls for new laboratory measurements of the dissociative recombination rate and branching ratio of the key ion H3+ under interstellar conditions.Comment: 27 pages, 6 figures, 3 table

Interaction Between The Broad-lined Type Ic Supernova 2012ap and Carriers of Diffuse Interstellar Bands

The diffuse interstellar bands (DIBs) are absorption features observed in optical and near-infrared spectra that are thought to be associated with carbon-rich polyatomic molecules in interstellar gas. However, because the central wavelengths of these bands do not correspond with electronic transitions of any known atomic or molecular species, their nature has remained uncertain since their discovery almost a century ago. Here we report on unusually strong DIBs in optical spectra of the broad-lined Type Ic supernova SN 2012ap that exhibit changes in equivalent width over short (~30 days) timescales. The 4428 and 6283 Angstrom DIB features get weaker with time, whereas the 5780 Angstrom feature shows a marginal increase. These nonuniform changes suggest that the supernova is interacting with a nearby source of the DIBs and that the DIB carriers possess high ionization potentials, such as small cations or charged fullerenes. We conclude that moderate-resolution spectra of supernovae with DIB absorptions obtained within weeks of outburst could reveal unique information about the mass-loss environment of their progenitor systems and provide new constraints on the properties of DIB carriers.Comment: 6 pages, 3 figures, accepted for publication in ApJ

EFFECT OF A SIX-WEEK NEUROMUSCULAR TRAINING PROGRAM ON VERTICAL STIFFNESS IN HEALTHY HIGH SCHOOL DISTANCE RUNNERS

Athletes, coaches, and health care teams know that preventing running-related injuries (RRI) and improving running performance are extremely important. Proactive neuromuscular training (NMT) is often included as a complement to running programs for this reason. The purpose of this study was to evaluate the effect of proactive six-week low-intensity NMT focused on proximal hip and thigh muscles on healthy high-school runners’ muscle strength, biomechanical stiffness, peak ground reaction force, cadence, and stride length. The study demonstrates that the NMT increased a runner’s total strength by 10.4% and knee extensor strength by 10.3%, showed no change in stiffness, cadence, or stride length, and showed a decrease in ground reaction force post-program by 1.3%. Results show the multivariable nature of RRI risk, and prompt further, more generalizable, evaluation

Inhomogeneity of the intrinsic magnetic field in superconducting YBa2Cu3OX compounds as revealed by rare-earth EPR-probe

X-band electron paramagnetic resonance on doped Er3+ and Yb3+ ions in Y0.99(Yb,Er)0.01Ba2Cu3OX compounds with different oxygen contents in the wide temperature range (4-120)K have been made. In the superconducting species, the strong dependencies of the linewidth and resonance line position from the sweep direction of the applied magnetic field are revealed at the temperatures significantly below TC. The possible origins of the observed hysteresis are analyzed. Applicability of the presented EPR approach to extract information about the dynamics of the flux-line lattice and critical state parameters (critical current density, magnetic penetration depth, and characteristic spatial scale of the inhomogeneity) is discussedComment: 17 pages, 5 Figures. Renewed versio

Designing Chatbots for Crises: A Case Study Contrasting Potential and Reality

Chatbots are becoming ubiquitous technologies, and their popularity and adoption are rapidly spreading. The potential of chatbots in engaging people with digital services is fully recognised. However, the reputation of this technology with regards to usefulness and real impact remains rather questionable. Studies that evaluate how people perceive and utilise chatbots are generally lacking. During the last Kenyan elections, we deployed a chatbot on Facebook Messenger to help people submit reports of violence and misconduct experienced in the polling stations. Even though the chatbot was visited by more than 3,000 times, there was a clear mismatch between the users’ perception of the technology and its design. In this paper, we analyse the user interactions and content generated through this application and discuss the challenges and directions for designing more effective chatbots

Resistive Transition and Upper Critical Field in Underdoped YBa_2Cu_3O_{6+x} Single Crystals

A superconducting transition in the temperature dependence of the ab-plane resistivity of underdoped YBa_2Cu_3O_{6+x} crystals in the range T_c<30 K has been investigated. Unlike the case of samples with the optimal level of doping, the transition width increased insignificantly with magnetic field, and in the range T_c<13 K it decreased with increasing magnetic field. The transition point T_c(B) was determined by analyzing the fluctuation conductivity. The curves of B_{c2}(T) measured in the region T/T_c>0.1 did not show a tendency to saturation and had a positive second derivative everywhere, including the immediate neighborhood of T_c. The only difference among the curves of B_{c2}(T) for different crystal states is the scales of T and B, so they can be described in terms of a universal function, which fairly closely follows Alexandrov's model of boson superconductivity.Comment: 10 Revtex pages, 6 figures, uses psfig.st

Supporting the consumption and co-authoring of locative media experiences for a rural village community: design and field trial evaluation of the SHARC2.0 framework

Locative Media Experiences (LMEs) have significant potential in enabling visitors to engage with the places that they visit through an appreciation of local history. For example, a visitor to Berlin that is exploring remnants of the Berlin Wall may be encouraged to appreciate (or in part experience) the falling of the Berlin wall by consuming multimedia directly related to her current location such as listening to audio recordings of the assembled crowds on 10th November 1989. However, despite the growing popularity of enabling technologies (such as GPS-equipped smart phones and tablets), the availability of tools that support the authoring of LMEs is limited. In addition, mobile apps that support the consumption of LMEs typically adopt an approach that precludes users from being able to respond with their own multimedia contributions. In this article we describe the design and evaluation of the SHARC2.0 framework that has been developed as part of our long-term and participatory engagement with the rural village of Wray in the north of England. Wray has very limited cellular data coverage which has placed a requirement on the framework and associated tools to operate without reliance on network connectivity. A field study is presented which featured a LME relating to Wray’s local history and which contained multimedia content contributed by members of the community including historic photos (taken from an existing ‘Digital Noticeboard’ system), audio-clips (from a local historian and village residents) and video (contributed during a design workshop). The novelty of our approach relates to the ability of multiple authors to contribute to a LME in-situ, and the utilisation of personal cloud storage for storing the contents associated with a multi-authored LME

Titan Cell Production Enhances the Virulence of Cryptococcus neoformans

ABSTRACT Infection with Cryptococcus neoformans begins when desiccated yeast cells or spores are inhaled and lodge in the alveoli of the lungs. A subset of cryptococcal cells in the lungs differentiate into enlarged cells, referred to as titan cells. Titan cells can be as large as 50 to 100 μm in diameter and exhibit a number of features that may affect interactions with host immune defenses. To characterize the effect of titan cell formation on the host-pathogen interaction, we utilized a previously described C. neoformans mutant, the gpr4 Δ gpr5 Δ mutant, which has minimal titan cell production in vivo . The gpr4 Δ gpr5 Δ mutant strain had attenuated virulence, a lower CFU, and reduced dissemination compared to the wild-type strain. Titan cell production by the wild-type strain also resulted in increased eosinophil accumulation and decreased phagocytosis in the lungs compared to those with the gpr4 Δ gpr5 Δ mutant strain. Phagocytosed cryptococcal cells exhibited less viability than nonphagocytosed cells, which potentially explains the reduced cell survival and overall attenuation of virulence in the absence of titan cells. These data show that titan cell formation is a novel virulence factor in C. neoformans that promotes establishment of the initial pulmonary infection and plays a key role in disease progression

Blockade of T-cell activation by dithiocarbamates involves novel mechanisms of inhibition of nuclear factor of activated T cells.

Dithiocarbamates (DTCs) have recently been reported as powerful inhibitors of NF-kappaB activation in a number of cell types. Given the role of this transcription factor in the regulation of gene expression in the inflammatory response, NF-kappaB inhibitors have been suggested as potential therapeutic drugs for inflammatory diseases. We show here that DTCs inhibited both interleukin 2 (IL-2) synthesis and membrane expression of antigens which are induced during T-cell activation. This inhibition, which occurred with a parallel activation of c-Jun transactivating functions and expression, was reflected by transfection experiments at the IL-2 promoter level, and involved not only the inhibition of NF-kappaB-driven reporter activation but also that of nuclear factor of activated T cells (NFAT). Accordingly, electrophoretic mobility shift assays (EMSAs) indicated that pyrrolidine DTC (PDTC) prevented NF-kappaB, and NFAT DNA-binding activity in T cells stimulated with either phorbol myristate acetate plus ionophore or antibodies against the CD3-T-cell receptor complex and simultaneously activated the binding of AP-1. Furthermore, PDTC differentially targeted both NFATp and NFATc family members, inhibiting the transactivation functions of NFATp and mRNA induction of NFATc. Strikingly, Western blotting and immunocytochemical experiments indicated that PDTC promoted a transient and rapid shuttling of NFATp and NFATc, leading to their accelerated export from the nucleus of activated T cells. We propose that the activation of an NFAT kinase by PDTC could be responsible for the rapid shuttling of the NFAT, therefore transiently converting the sustained transactivation of this transcription factor that occurs during lymphocyte activation, and show that c-Jun NH2-terminal kinase (JNK) can act by directly phosphorylating NFATp. In addition, the combined inhibitory effects on NFAT and NF-KB support a potential use of DTCs as immunosuppressants