1,251 research outputs found
The Nature of Nonthermal X-ray Filaments Near the Galactic Center
Recent Chandra and XMM-{\it Newton} observations reported evidence of two
X-ray filaments G359.88-0.08 (SgrA-E) and G359.54+0.18 (the ripple filament)
near the Galactic center. The X-ray emission from these filaments has a
nonthermal spectrum and coincides with synchrotron emitting radio sources.
Here, we report the detection of a new X-ray feature coincident with a radio
filament G359.90-0.06 (SgrA-F) and show more detailed VLA, Chandra and BIMA
observations of the radio and X-ray filaments. In particular, we show that
radio emission from the nonthermal filaments G359.90-0.06 (SgrA-F) and
G359.54+0.18 (the ripple) has a steep spectrum whereas G359.88-0.08 (SgrA-E)
has a flat spectrum. The X-ray emission from both these sources could be due to
synchrotron radiation. However, given that the 20 \kms molecular cloud, with
its intense 1.2mm dust emission, lies in the vicinity of SgrA-F, it is possible
that the X-rays could be produced by inverse Compton scattering of far-infrared
photons from dust by the relativistic electrons responsible for the radio
synchrotron emission. The production of X-ray emission from ICS allows an
estimate of the magnetic field strength of ~0.08 mG within the nonthermal
filament. This should be an important parameter for any models of the Galactic
center nonthermal filaments.Comment: 14 pages, 9 figures, in Cospar 2004 session E1.4; editors: Cara
Rakowski and Shami Chatterjee; "Young Neutron Stars and Supernova Remnants",
publication: Advances in Space Research (in press
Increasing Patient Engagement in Pharmacovigilance Through Online Community Outreach and Mobile Reporting Applications: An Analysis of Adverse Event Reporting for the Essure Device in the US
BACKGROUND: Preparing and submitting a voluntary adverse event (AE) report to the US Food and Drug Administration (FDA) for a medical device typically takes 40 min. User-friendly Web and mobile reporting apps may increase efficiency. Further, coupled with strategies for direct patient involvement, patient engagement in AE reporting may be improved. In 2012, the FDA Center for Devices and Radiologic Health (CDRH) launched a free, public mobile AE reporting app, MedWatcher, for patients and clinicians. During the same year, a patient community on Facebook adopted the app to submit reports involving a hysteroscopic sterilization device, brand name Essure(®). METHODS: Patient community outreach was conducted to administrators of the group “Essure Problems” (approximately 18,000 members as of June 2015) to gather individual case safety reports (ICSRs). After agreeing on key reporting principles, group administrators encouraged members to report via the app. Semi-structured forms in the app mirrored fields of the MedWatch 3500 form. ICSRs were transmitted to CDRH via an electronic gateway, and anonymized versions were posted in the app. Data collected from May 11, 2013 to December 7, 2014 were analyzed. Narrative texts were coded by trained and certified MedDRA coders (version 17). Descriptive statistics and metrics, including VigiGrade completeness scores, were analyzed. Various incentives and motivations to report in the Facebook group were observed. RESULTS: The average Essure AE report took 11.4 min (±10) to complete. Submissions from 1349 women, average age 34 years, were analyzed. Serious events, including hospitalization, disability, and permanent damage after implantation, were reported by 1047 women (77.6 %). A total of 13,135 product–event pairs were reported, comprising 327 unique preferred terms, most frequently fatigue (n = 491), back pain (468), and pelvic pain (459). Important medical events (IMEs), most frequently mental impairment (142), device dislocation (108), and salpingectomy (62), were reported by 598 women (44.3 %). Other events of interest included loss of libido (n = 115); allergy to metals (109), primarily nickel; and alopecia (252). VigiGrade completeness scores were high, averaging 0.80 (±0.15). Reports received via the mobile app were considered “well documented” 55.9 % of the time, compared with an international average of 13 % for all medical products. On average, there were 15 times more reports submitted per month via the app with patient community support versus traditional pharmacovigilance portals. CONCLUSIONS: Outreach via an online patient community, coupled with an easy-to-use app, allowed for rapid and detailed ICSRs to be submitted, with gains in efficiency. Two-way communication and public posting of narratives led to successful engagement within a Motivation-Incentive-Activation-Behavior framework, a conceptual model for successful crowdsourcing. Reports submitted by patients were considerably more complete than those submitted by physicians in routine spontaneous reports. Further research is needed to understand how biases operate differently from those of traditional pharmacovigilance
A new interpretation of total column BrO during Arctic spring
Emission of bromine from sea-salt aerosol, frost flowers, ice leads, and snow results in the nearly complete removal of surface ozone during Arctic spring. Regions of enhanced total column BrO observed by satellites have traditionally been associated with these emissions. However, airborne measurements of BrO and O3 within the convective boundary layer (CBL) during the ARCTAS and ARCPAC field campaigns at times bear little relation to enhanced column BrO. We show that the locations of numerous satellite BrO “hotspots” during Arctic spring are consistent with observations of total column ozone and tropopause height, suggesting a stratospheric origin to these regions of elevated BrO. Tropospheric enhancements of BrO large enough to affect the column abundance are also observed, with important contributions originating from above the CBL. Closure of the budget for total column BrO, albeit with significant uncertainty, is achieved by summing observed tropospheric partial columns with calculated stratospheric partial columns provided that natural, short-lived biogenic bromocarbons supply between 5 and 10 ppt of bromine to the Arctic lowermost stratosphere. Proper understanding of bromine and its effects on atmospheric composition requires accurate treatment of geographic variations in column BrO originating from both the stratosphere and troposphere
The cardiac and haemostatic effects of dietary hempseed
Despite its use in our diet for hundreds of years, hempseed has surprisingly little research published on its physiological effects. This may have been in the past because the psychotropic properties wrongly attributed to hemp would complicate any conclusions obtained through its study. Hemp has a botanical relationship to drug/medicinal varieties of Cannabis. However, hempseed no longer contains psychotropic action and instead may provide significant health benefits. Hempseed has an excellent content of omega-3 and omega-6 fatty acids. These compounds have beneficial effects on our cardiovascular health. Recent studies, mostly in animals, have examined the effects of these fatty acids and dietary hempseed itself on platelet aggregation, ischemic heart disease and other aspects of our cardiovascular health. The purpose of this article is to review the latest developments in this rapidly emerging research field with a focus on the cardiac and vascular effects of dietary hempseed
Ethanol reversal of tolerance to the respiratory depressant effects of morphine
Opioids are the most common drugs associated with unintentional drug overdose. Death results from respiratory depression. Prolonged use of opioids results in the development of tolerance but the degree of tolerance is thought to vary between different effects of the drugs. Many opioid addicts regularly consume alcohol (ethanol), and post-mortem analyses of opioid overdose deaths have revealed an inverse correlation between blood morphine and ethanol levels. In the present study, we determined whether ethanol reduced tolerance to the respiratory depressant effects of opioids. Mice were treated with opioids (morphine, methadone, or buprenorphine) for up to 6 days. Respiration was measured in freely moving animals breathing 5% CO(2) in air in plethysmograph chambers. Antinociception (analgesia) was measured as the latency to remove the tail from a thermal stimulus. Opioid tolerance was assessed by measuring the response to a challenge dose of morphine (10 mg/kg i.p.). Tolerance developed to the respiratory depressant effect of morphine but at a slower rate than tolerance to its antinociceptive effect. A low dose of ethanol (0.3 mg/kg) alone did not depress respiration but in prolonged morphine-treated animals respiratory depression was observed when ethanol was co-administered with the morphine challenge. Ethanol did not alter the brain levels of morphine. In contrast, in methadone- or buprenorphine-treated animals no respiratory depression was observed when ethanol was co-administered along with the morphine challenge. As heroin is converted to morphine in man, selective reversal of morphine tolerance by ethanol may be a contributory factor in heroin overdose deaths
The Bolocam Galactic Plane Survey IV: 1.1 and 0.35 mm Dust Continuum Emission in the Galactic Center Region
The Bolocam Galactic Plane Survey (BGPS) data for a six square degree region
of the Galactic plane containing the Galactic center is analyzed and compared
to infrared and radio continuum data. The BGPS 1.1 mm emission consists of
clumps interconnected by a network of fainter filaments surrounding cavities, a
few of which are filled with diffuse near-IR emission indicating the presence
of warm dust or with radio continuum characteristic of HII regions or supernova
remnants. New 350 {\mu}m images of the environments of the two brightest
regions, Sgr A and B, are presented. Sgr B2 is the brightest mm-emitting clump
in the Central Molecular Zone and may be forming the closest analog to a super
star cluster in the Galaxy. The Central Molecular Zone (CMZ) contains the
highest concentration of mm and sub-mm emitting dense clumps in the Galaxy.
Most 1.1 mm features at positive longitudes are seen in silhouette against the
3.6 to 24 {\mu}m background observed by the Spitzer Space Telescope. However,
only a few clumps at negative longitudes are seen in absorption, confirming the
hypothesis that positive longitude clumps in the CMZ tend to be on the
near-side of the Galactic center, consistent with the suspected orientation of
the central bar in our Galaxy. Some 1.1 mm cloud surfaces are seen in emission
at 8 {\mu}m, presumably due to polycyclic aromatic hydrocarbons (PAHs). A
~0.2\degree (~30 pc) diameter cavity and infrared bubble between l \approx
0.0\degree and 0.2\degree surrounds the Arches and Quintuplet clusters and Sgr
A. The bubble contains several clumpy dust filaments that point toward Sgr
A\ast; its potential role in their formation is explored. [abstract truncated]Comment: 76 pages, 22 figures, published in ApJ:
http://iopscience.iop.org/0004-637X/721/1/137
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A new interpretation of total column BrO during Arctic spring
Emission of bromine from sea-salt aerosol, frost flowers, ice leads, and snow results in the nearly complete removal of surface ozone during Arctic spring. Regions of enhanced total column BrO observed by satellites have traditionally been associated with these emissions. However, airborne measurements of BrO and O3 within the convective boundary layer (CBL) during the ARCTAS and ARCPAC field campaigns at times bear little relation to enhanced column BrO. We show that the locations of numerous satellite BrO "hotspots" during Arctic spring are consistent with observations of total column ozone and tropopause height, suggesting a stratospheric origin to these regions of elevated BrO. Tropospheric enhancements of BrO large enough to affect the column abundance are also observed, with important contributions originating from above the CBL. Closure of the budget for total column BrO, albeit with significant uncertainty, is achieved by summing observed tropospheric partial columns with calculated stratospheric partial columns provided that natural, short-lived biogenic bromocarbons supply between 5 and 10 ppt of bromine to the Arctic lowermost stratosphere. Proper understanding of bromine and its effects on atmospheric composition requires accurate treatment of geographic variations in column BrO originating from both the stratosphere and troposphere. Copyright 2010 by the American Geophysical Union
Plant responses to photoperiod
Photoperiod controls many developmental responses in animals, plants and even fungi. The response to photoperiod has evolved because daylength is a reliable indicator
of the time of year, enabling developmental events to be scheduled to coincide with particular environmental conditions. Much progress has been made towards
understanding the molecular mechanisms involved in the response to photoperiod in plants. These mechanisms include the detection of the light signal in the leaves,
the entrainment of circadian rhythms, and the production of a mobile signal which is transmitted throughout the plant. Flowering, tuberization and bud set are just a few of the many different responses in plants that are under photoperiodic control. Comparison of what is known of the molecular mechanisms controlling these responses shows that, whilst common components exist, significant differences in the regulatory mechanisms have evolved between these responses
Higgs Boson Theory and Phenomenology
Precision electroweak data presently favors a weakly-coupled Higgs sector as
the mechanism responsible for electroweak symmetry breaking. Low-energy
supersymmetry provides a natural framework for weakly-coupled elementary
scalars. In this review, we summarize the theoretical properties of the
Standard Model (SM) Higgs boson and the Higgs sector of the minimal
supersymmetric extension of the Standard Model (MSSM). We then survey the
phenomenology of the SM and MSSM Higgs bosons at the Tevatron, LHC and a future
e+e- linear collider. We focus on the Higgs discovery potential of present and
future colliders and stress the importance of precision measurements of Higgs
boson properties.Comment: 90 pages, 31 figures. Revised version. To be published in Progress in
Particle and Nuclear Physics. This paper with higher resolution figures can
be found at http://scipp.ucsc.edu/~haber/higgsreview/higgsrev.p
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