108 research outputs found

    The 67 Hz Feature in the Black Hole Candidate GRS 1915+105 as a Possible ``Diskoseismic'' Mode

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    The Rossi X-ray Timing Explorer (RXTE) has made feasible for the first time the search for high-frequency (~ 100 Hz) periodic features in black hole candidate (BHC) systems. Such a feature, with a 67 Hz frequency, recently has been discovered in the BHC GRS 1915+105 (Morgan, Remillard, & Greiner). This feature is weak (rms variability ~0.3%-1.6%), stable in frequency (to within ~2 Hz) despite appreciable luminosity fluctuations, and narrow (quality factor Q ~ 20). Several of these properties are what one expects for a ``diskoseismic'' g-mode in an accretion disk about a 10.6 M_sun (nonrotating) - 36.3 M_sun (maximally rotating) black hole (if we are observing the fundamental mode frequency). We explore this possibility by considering the expected luminosity modulation, as well as possible excitation and growth mechanisms---including turbulent excitation, damping, and ``negative'' radiation damping. We conclude that a diskoseismic interpretation of the observations is viable.Comment: 4 Pages, Latex (emulateapj.sty included), to Appear in ApJ Letters, Vol. 477, Final Version with Updated Reference

    The Comparison Between Skilled Vestibular Therapy and Neuromuscular Reeducation Following a Mild Traumatic Brain Injury: A Critically Appraised Topic

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    Vestibular therapy is a specialized form of physical therapy used to treat vestibular disorders or symptoms, characterized by dizziness, vertigo, and trouble with balance, posture, and vision. CDC reports from 2001-2009, the estimated number of ER visits for sports and recreational related concussions increased 62% in those 19 years old or younger, Abnormal vestibular information affects the position and movement of the head in space. Inaccurate vestibular input requires the brain to rely on the visual system which can result in fatigue and difficulty performing activities of daily living? Traditional concussion management consists of rest until complete resolution of symptoms, resulting in slower recovery and prolonged symptoms. The purpose of our research is to determine the effectiveness of skilled vestibular therapy or neuromuscular rehabilitation to reduce symptoms following a mild traumatic brain injury

    The Effectiveness of Grade 5 Mobilizations vs. Grade 1-4 Mobilizations on Mechanical Neck Pain: A Clinically Appraised Topic

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    • From 2000 to 2010, mechanical neck pain (MNP) prevalence ranged from 30% to 50% in adults. Other data suggests that 46% to 54% of every adult will experience some form of neck pain during their lives. • Non-thrust mobilizations (NTM) and Thrust mobilizations (TM) are among the common interventions used in manual therapy in treatment of MNP. • The evidence accumulated for this clinically appraised topic (CAT) suggests high clinical variability among the effectiveness in NTM and TM among adults with mechanical neck pain

    Protein-Binding Microarray Analysis of Tumor Suppressor AP2α Target Gene Specificity

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    Cheap and massively parallel methods to assess the DNA-binding specificity of transcription factors are actively sought, given their prominent regulatory role in cellular processes and diseases. Here we evaluated the use of protein-binding microarrays (PBM) to probe the association of the tumor suppressor AP2α with 6000 human genomic DNA regulatory sequences. We show that the PBM provides accurate relative binding affinities when compared to quantitative surface plasmon resonance assays. A PBM-based study of human healthy and breast tumor tissue extracts allowed the identification of previously unknown AP2α target genes and it revealed genes whose direct or indirect interactions with AP2α are affected in the diseased tissues. AP2α binding and regulation was confirmed experimentally in human carcinoma cells for novel target genes involved in tumor progression and resistance to chemotherapeutics, providing a molecular interpretation of AP2α role in cancer chemoresistance. Overall, we conclude that this approach provides quantitative and accurate assays of the specificity and activity of tumor suppressor and oncogenic proteins in clinical samples, interfacing genomic and proteomic assays

    Centerscope

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    Centerscope, formerly Scope, was published by the Boston University Medical Center "to communicate the concern of the Medical Center for the development and maintenance of improved health care in contemporary society.

    Ecological Guild Evolution and the Discovery of the World's Smallest Vertebrate

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    Living vertebrates vary drastically in body size, yet few taxa reach the extremely minute size of some frogs and teleost fish. Here we describe two new species of diminutive terrestrial frogs from the megadiverse hotspot island of New Guinea, one of which represents the smallest known vertebrate species, attaining an average body size of only 7.7 mm. Both new species are members of the recently described genus Paedophryne, the four species of which are all among the ten smallest known frog species, making Paedophryne the most diminutive genus of anurans. This discovery highlights intriguing ecological similarities among the numerous independent origins of diminutive anurans, suggesting that minute frogs are not mere oddities, but represent a previously unrecognized ecological guild

    Diverse Applications of Nanomedicine

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    The design and use of materials in the nanoscale size range for addressing medical and health-related issues continues to receive increasing interest. Research in nanomedicine spans a multitude of areas, including drug delivery, vaccine development, antibacterial, diagnosis and imaging tools, wearable devices, implants, high-throughput screening platforms, etc. using biological, nonbiological, biomimetic, or hybrid materials. Many of these developments are starting to be translated into viable clinical products. Here, we provide an overview of recent developments in nanomedicine and highlight the current challenges and upcoming opportunities for the field and translation to the clinic. \ua9 2017 American Chemical Society
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