1,642 research outputs found

    K2 reveals pulsed accretion driven by the 2 Myr old hot Jupiter CI Tau b

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    CI Tau is a young (~2 Myr) classical T Tauri star located in the Taurus star forming region. Radial velocity observations indicate it hosts a Jupiter-sized planet with an orbital period of approximately 9 days. In this work, we analyze time series of CI Tau's photometric variability as seen by K2. The lightcurve reveals the stellar rotation period to be ~6.6 d. Although there is no evidence that CI Tau b transits the host star, a ~9 d signature is also present in the lightcurve. We believe this is most likely caused by planet-disk interactions which perturb the accretion flow onto the star, resulting in a periodic modulation of the brightness with the ~9 d period of the planet's orbit.Comment: Accepted for publication in ApJ Letter

    Activation of Innate Immune-Response Genes in Little Brown Bats (Myotis lucifugus) Infected with the Fungus Pseudogymnoascus destructans

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    Recently bats have been associated with the emergence of diseases, both as reservoirs for several new viral diseases in humans and other animals and, in the northern Americas, as hosts for a devastating fungal disease that threatens to drive several bat species to regional extinction. However, despite these catastrophic events little Information is available on bat defences or how they interact with their pathogens. Even less is known about the response of bats to infection during torpor or long-term hibernation. Using tissue samples collected at the termination of an experiment to explore the pathogenesis of White Nose Syndrome in Little Brown Bats, we determined if hibernating bats infected with the fungus Pseudogymnoascus destructans could respond to infection by activating genes responsible for innate immune and stress responses. Lesions due to fungal infection and, in some cases, secondary bacterial infections, were restricted to the skin. However, we were unable to obtain sufficient amounts of RNA from these sites. We therefore examined lungs for response at an epithelial surface not linked to the primary site of infection. We found that bats responded to infection with a significant increase in lungs of transcripts for Cathelicidin (an anti-microbial peptide) as well as the immune modulators tumor necrosis factor alpha and interleukins 10 and 23. In conclusion, hibernating bats can respond to experimental P. destructans infection by activating expression of innate immune response genes.Funding for this study was provided by a Fish and Wildlife Service grant to CRKW, TB and VM and by a Natural Sciences and Engineering Research Council (Discovery) grant to VM and a fellowship within the Postdoc Programme of the DAAD, German Academic Exchange Service (to LW). The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript.https://journals.plos.org/plosone/article?id=10.1371/journal.pone.011228

    Momordica charantia (bitter melon) attenuates high-fat diet-associated oxidative stress and neuroinflammation

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    <p>Abstract</p> <p>Background</p> <p>The rising epidemic of obesity is associated with cognitive decline and is considered as one of the major risk factors for neurodegenerative diseases. Neuroinflammation is a critical component in the progression of several neurological and neurodegenerative diseases. Increased metabolic flux to the brain during overnutrition and obesity can orchestrate stress response, blood-brain barrier (BBB) disruption, recruitment of inflammatory immune cells from peripheral blood and microglial cells activation leading to neuroinflammation. The lack of an effective treatment for obesity-associated brain dysfunction may have far-reaching public health ramifications, urgently necessitating the identification of appropriate preventive and therapeutic strategies. The objective of our study was to investigate the neuroprotective effects of <it>Momordica charantia </it>(bitter melon) on high-fat diet (HFD)-associated BBB disruption, stress and neuroinflammatory cytokines.</p> <p>Methods</p> <p>C57BL/6 female mice were fed HFD with and without bitter melon (BM) for 16 weeks. BBB disruption was analyzed using Evans blue dye. Phosphate-buffered saline (PBS) perfused brains were analyzed for neuroinflammatory markers such as interleukin-22 (IL-22), IL-17R, IL-16, NF-κB1, and glial cells activation markers such as Iba1, CD11b, GFAP and S100β. Additionally, antioxidant enzymes, ER-stress proteins, and stress-resistant transcription factors, sirtuin 1 (Sirt1) and forkhead box class O transcription factor (FoxO) were analyzed using microarray, quantitative real-time RT-PCR, western immunoblotting and enzymatic assays. Systemic inflammation was analyzed using cytokine antibody array.</p> <p>Results</p> <p>BM ameliorated HFD-associated changes in BBB permeability as evident by reduced leakage of Evans blue dye. HFD-induced glial cells activation and expression of neuroinflammatory markers such as NF-κB1, IL-16, IL-22 as well as IL-17R were normalized in the brains of mice supplemented with BM. Similarly, HFD-induced brain oxidative stress was significantly reduced by BM supplementation with a concomitant reduction in FoxO, normalization of Sirt1 protein expression and up-regulation of Sirt3 mRNA expression. Furthermore, plasma antioxidant enzymes and pro-inflammatory cytokines were also normalized in mice fed HFD with BM as compared to HFD-fed mice.</p> <p>Conclusions</p> <p>Functional foods such as BM offer a unique therapeutic strategy to improve obesity-associated peripheral inflammation and neuroinflammation.</p

    Sea surface slope as a proxy for Agulhas Current strength

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    The linear relation between the strength of the Agulhas Current at nominal latitude 34°S and the gradient in sea level height anomaly across the current is investigated in a 1/10° resolution regional numerical ocean model. Our results show that the strength of the current can be estimated with reasonable accuracy using altimeter data, once it has been calibrated using in-situ transport measurements. Three years of transport measurements provide a calibration with worst-case correlation R = 0.78. In that case the errors in proxy transport have a standard deviation of 9.8 Sv, compared to a 20.2 Sv standard deviation of the transport time series itself. From these results we conclude that the design of the Agulhas Current Timeseries (ACT) experiment, a three-year deployment of moorings across the Agulhas Current and along a TOPEX/Jason altimeter ground track, will likely produce a good quality multi-decadal time series of Agulhas Current strength

    Hidden expectations: Scaffolding subject specialists' genre knowledge of the assignments they set

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    Subject specialists’ knowledge of academic and disciplinary literacy is often tacit. We tackle the issue of how to elicit subject specialists’ tacit knowledge in order to develop their pedagogical practices and enable them to communicate this knowledge to students. Drawing on theories of genre and metacognition, a professional development activity was designed and delivered. Our aims were to (1) build participants’ genre knowledge and (2) scaffold metacognitive awareness of how genre knowledge can enhance their pedagogical practices. The findings reveal that participants built a genre-based understanding of academic literacy and that the tasks provided them with an accessible framework to articulate and reflect upon their knowledge of disciplinary literacy. Participants gained metacognitive awareness of misalignments between what they teach and what they expect from students, their assumptions about students’ prior learning and genre-based strategies to adapt their practice to students’ needs. Our approach provides a theoretically grounded professional development tool for the HE sector

    The Heavy Vehicle Study: a case-control study investigating risk factors for crash in long distance heavy vehicle drivers in Australia

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    Background Heavy vehicle transportation continues to grow internationally; yet crash rates are high, and the risk of injury and death extends to all road users. The work environment for the heavy vehicle driver poses many challenges; conditions such as scheduling and payment are proposed risk factors for crash, yet the precise measure of these needs quantifying. Other risk factors such as sleep disorders including obstructive sleep apnoea have been shown to increase crash risk in motor vehicle drivers however the risk of heavy vehicle crash from this and related health conditions needs detailed investigation. Methods and Design The proposed case control study will recruit 1034 long distance heavy vehicle drivers: 517 who have crashed and 517 who have not. All participants will be interviewed at length, regarding their driving and crash history, typical workloads, scheduling and payment, trip history over several days, sleep patterns, health, and substance use. All participants will have administered a nasal flow monitor for the detection of obstructive sleep apnoea. Discussion Significant attention has been paid to the enforcement of legislation aiming to deter problems such as excess loading, speeding and substance use; however, there is inconclusive evidence as to the direction and strength of associations of many other postulated risk factors for heavy vehicle crashes. The influence of factors such as remuneration and scheduling on crash risk is unclear; so too the association between sleep apnoea and the risk of heavy vehicle driver crash. Contributory factors such as sleep quality and quantity, body mass and health status will be investigated. Quantifying the measure of effect of these factors on the heavy vehicle driver will inform policy development that aims toward safer driving practices and reduction in heavy vehicle crash; protecting the lives of many on the road network

    Hα Variability in PTFO 8-8695 and the possible direct detection of emission from a 2 million year old evaporating hot Jupiter

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    We use high time cadence, high spectral resolution optical observations to detect excess Hα emission from the 2-3 Myr old weak-lined T Tauri star PTFO 8-8695. This excess emission appears to move in velocity as expected if it were produced by the suspected planetary companion to this young star. The excess emission is not always present, but when it is, the predicted velocity motion is often observed. We have considered the possibility that the observed excess emission is produced by stellar activity (flares), accretion from a disk, or a planetary companion; we find the planetary companion to be the most likely explanation. If this is the case, the strength of the Hα line indicates that the emission comes from an extended volume around the planet, likely fed by mass loss from the planet which is expected to be overflowing its Roche lobe

    Hα Variability in PTFO8-8695 and the Possible Direct Detection of Emission from a 2 Million Year Old Evaporating Hot Jupiter

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    We use high time cadence, high spectral resolution optical observations to detect excess Hα emission from the 2–3 Myr old weak-lined T Tauri star PTFO 8-8695. This excess emission appears to move in velocity as expected if it were produced by the suspected planetary companion to this young star. The excess emission is not always present, but when it is, the predicted velocity motion is often observed. We have considered the possibility that the observed excess emission is produced by stellar activity (flares), accretion from a disk, or a planetary companion; we find the planetary companion to be the most likely explanation. If this is the case, the strength of the Hα line indicates that the emission comes from an extended volume around the planet, likely fed by mass loss from the planet which is expected to be overflowing its Roche lobe
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