4,946 research outputs found

    Quiescent photometric modulations of two low-inclination cataclysmic variables KZGem and TWVir

    Full text link
    The quiescent periodic photometric modulations of two low-inclination cataclysmic variables observed in Kepler K2 Campaigns 0 and 1, KZ Gem and TW Vir, are investigated. A phase-correcting method was successfully used to detect the orbital modulations of KZ Gem and TW Vir and improve their orbital periods. The light curve morphologies of both CVs were further analyzed by defining flux ratios and creating colormaps. KZ Gem shows ellipsoidal modulations with an orbital period of 0.22242(1) day, twice the period listed in the updated RK catalogue (Edition 7.24). With this newly determined period, KZ Gem is no longer a CV in the period gap, but a long-period CV. A part of the quiescent light curve of TW Vir that had the highest stability was used to deduce its improved orbital period of 0.182682(3) day. The flat patterns shown in the colormaps of the flux ratios for KZ Gem demonstrate the stability of their orbital modulations, while TW Vir show variable orbital modulations during the K2 datasets. In TW Vir, the single versus double-peaked nature of the quiescent orbital variations before and after superoutburst may be related to the effect of the superoutburst on the accretion disk.Comment: 10 pages, 12 figures, accepted by A&

    A sex difference in the response of the rodent postsynaptic density to synGAP haploinsufficiency

    Get PDF
    SynGAP is a postsynaptic density (PSD) protein that binds to PDZ domains of the scaffold protein PSD-95. We previously reported that heterozygous deletion of Syngap1 in mice is correlated with increased steady-state levels of other key PSD proteins that bind PSD-95, although the level of PSD-95 remains constant (Walkup et al., 2016). For example, the ratio to PSD-95 of Transmembrane AMPA-Receptor-associated Proteins (TARPs), which mediate binding of AMPA-type glutamate receptors to PSD-95, was increased in young Syngap1+/- mice. Here we show that only females and not males show a highly significant correlation between an increase in TARP and a decrease in synGAP in the PSDs of Syngap1+/- rodents. The data reveal a sex difference in the adaptation of the PSD scaffold to synGAP haploinsufficiency

    China Maritime Report No. 6: Djibouti: China\u27s First Overseas Strategic Strongpoint

    Get PDF
    This China Maritime Report on Djibouti is the first in a series of case studies on Chinaā€™s ā€œoverseas strategic strongpointsā€ (ęµ·å¤–ęˆ˜ē•„ę”Æē‚¹). The strategic strongpoint concept has no formal definition, but is used by Peopleā€™s Republic of China (PRC) officials and analysts to describe foreign ports with special strategic and economic value that host terminals and commercial zones operated by Chinese firms.https://digital-commons.usnwc.edu/cmsi-maritime-reports/1005/thumbnail.jp

    China Maritime Report No. 7: Gwadar: China\u27s Potential Strategic Strongpoint in Pakistan

    Get PDF
    This China Maritime Report on Gwadar is the second in a series of case studies on Chinaā€™s Indian Ocean ā€œstrategic strongpointsā€ (ꈘē•„ę”Æē‚¹). Peopleā€™s Republic of China (PRC) officials, military officers, and civilian analysts use the strategic strongpoint concept to describe certain strategically valuable foreign ports with terminals and commercial zones owned and operated by Chinese firms.https://digital-commons.usnwc.edu/cmsi-maritime-reports/1006/thumbnail.jp

    Influence of initial conditions on the fundamental periods of LFSR-dithered MASH digital delta-sigma modulators with constant inputs

    Get PDF
    A digital delta-sigma modulator (DDSM) with a constant input may produce a periodic output with a small fundamental period, resulting in strong tonal output behavior instead of the expected shaped white quantization noise. In practice, the problem is alleviated by dithering the DDSM. Pseudorandom dither generators based on linear feedback shift registers (LFSRs) are widely used to "break up" periodic cycles in DDSMs with constant inputs. Pseudorandom dither signals are themselves periodic and can lead to relatively short output sequences from dithered DDSMs. It is known that the fundamental period of the output signal depends not only on the input and the initial condition of the DDSM but also on the initial state of the LFSR. This brief shows that bad LFSR initial conditions can lead to ineffective dithering, producing short cycles and strong tonal behavior. Furthermore, it explains how to set the initial state of the DDSM as a function of the initial state of the LFSR in order to obtain a maximum-length dithered output

    The Production of Hospitable Space: Commercial Propositions and Consumer Co-Creation in a Bar Operation

    Get PDF
    This paper examines the processes through which a commercial bar is transformed into a hospitable space. Drawing on a study of a venue patronized by lesbian, gay, bisexual and transsexual/transgender consumers, it considers how social and commercial forms of hospitality are mobilized. The paper argues that hospitable space has an ideological, normative and situational dimension. More specifically, it suggests the barā€™s operation is tied to a set of ideological conceptions, which become the potential basis of association and disassociation among consumers. It examines the forces and processes that shape who participates in the production and consumption of hospitality and how. Finally, it considers the situational, emergent nature of hospitality and the discontinuous production of hospitable space. Rather than focusing exclusively on host-guest or provider-customer relations, which dominates existing work on hospitality, the paper examines how consumersā€™ perceptions, actions and interactions shape the production of hospitality. By doing so the paper offers an alternative approach to understanding queer spaces, bar operation as well as hospitality

    The relationship of endotoxaemia to peripheral and central nervous system inflammatory responses in Human African Trypanosomiasis

    Get PDF
    Endotoxaemia has been described in cases of Human African trypanosomiasis (HAT), but it is unclear if this phenomenon influences inflammatory pathology either in the periphery or central nervous system (CNS). We studied endotoxin concentrations in the plasma and cerebrospinal fluid (CSF) of Trypanosoma brucei rhodesiense patients using the chromogenic Limulus Amoebocyte lysate assay. The relationship of endotoxin concentration to the presentation of gross signs of inflammation and the inflammatory/counter-inflammatory cytokine profile of the relevant compartments were analysed. We demonstrate that HAT patients exhibit parasitaemia-independent plasma endotoxaemia, and that this is associated with splenomegaly and lymphadenopathy. Endotoxin concentrations normalize rapidly after treatment. There was no evidence of endotoxin release in the CNS. A rapid normalization of endotoxin levels after treatment and lack of association with parasitaemia suggest that gut leakage is the main source of endotoxin in the circulation. Low CSF endotoxin concentrations and a lack of any association with neuroinflammatory markers or neurological sequelae suggest that endotoxin does not play a role in the pathogenesis of the disease in the CNS

    Long-term photometric variations in the candidate white-dwarf pulsar AR Scorpii from K2 , CRTS, and ASAS-SN observations

    Get PDF
    We analyze long-cadence Kepler K2 observations of AR Sco from 2014, along with survey photometry obtained between 2005 and 2016 by the Catalina Real-Time Sky Survey and the All-Sky Automated Survey for Supernovae. The K2 data show the orbital modulation to have been fairly stable during the 78 days of observations, but we detect aperiodic deviations from the average waveform with an amplitude of ~2% on a timescale of a few days. A comparison of the K2 data with the survey photometry reveals that the orbital waveform gradually changed between 2005 and 2010, with the orbital maximum shifting to earlier phases. We compare these photometric variations with proposed models of this unusual system
    • ā€¦
    corecore