5,677 research outputs found
The Asymmetric Rotor. IX. The Heavy Water Bands at 2787 cm^β1 and 5373 cm^β1
The combination band (110) of the two stretching fundamentals of D2O is reported and analyzed to yield nu0=5373.2 cm^β1 and the excited state moments of inertia 1.910, 3.931, and 5.929Γ10^β40 g cm^2. The same method of analysis applied to the unsymmetrical fundamental band (100) envelope gives nu0=2787.5 cm^β1 and the excited state moments 1.881, 3.876, and 5.843Γ10^β40 g cm^2
The Dynamics of Radiative Shock Waves: Linear and Nonlinear Evolution
The stability properties of one-dimensional radiative shocks with a power-law
cooling function of the form are the main
subject of this work. The linear analysis originally presented by Chevalier &
Imamura, is thoroughfully reviewed for several values of the cooling index
and higher overtone modes. Consistently with previous results, it is
shown that the spectrum of the linear operator consists in a series of modes
with increasing oscillation frequency. For each mode a critical value of the
cooling index, , can be defined so that modes with are unstable, while modes with
are stable. The perturbative analysis is complemented by several numerical
simulations to follow the time-dependent evolution of the system for different
values of . Particular attention is given to the comparison between
numerical and analytical results (during the early phases of the evolution) and
to the role played by different boundary conditions. It is shown that an
appropriate treatment of the lower boundary yields results that closely follow
the predicted linear behavior. During the nonlinear regime, the shock
oscillations saturate at a finite amplitude and tend to a quasi-periodic cycle.
The modes of oscillations during this phase do not necessarily coincide with
those predicted by linear theory, but may be accounted for by mode-mode
coupling.Comment: 33 pages, 12 figures, accepted for publication on the Astrophysical
Journa
Destabilization of a Solar Prominence/Filament Field System by a Series of Eight Homologous Eruptive Flares
Homologous flares are flares that occur repetitively in the same active
region, with similar structure and morphology. A series of at least eight
homologous flares occurred in active region NOAA 11237 over 16 - 17 June 2011.
A nearby prominence/filament was rooted in the active region, and situated near
the bottom of a coronal cavity. The active region was on the southeast solar
limb as seen from SDO/AIA, and on the disk as viewed from STEREO/EUVI-B. The
dual perspective allows us to study in detail behavior of the
prominence/filament material entrained in the magnetic field of the
repeatedly-erupting system. Each of the eruptions was mainly confined, but
expelled hot material into the prominence/filament cavity system (PFCS). The
field carrying and containing the ejected hot material interacted with the PFCS
and caused it to inflate, resulting in a step-wise rise of the PFCS
approximately in step with the homologous eruptions. The eighth eruption
triggered the PFCS to move outward slowly, accompanied by a weak coronal
dimming. As this slow PFCS eruption was underway, a final ejective flare
occurred in the core of the active region, resulting in strong dimming in the
EUVI-B images and expulsion of a coronal mass ejection (CME). A plausible
scenario is that the repeated homologous flares could have gradually
destabilized the PFCS, and its subsequent eruption removed field above the
acitive region and in turn led to the ejective flare, strong dimming, and CME.Comment: 11 pages, 12 figures, Accepted for publication in Ap
EIS/Hinode observations of Doppler flow seen through the 40 arcsec wide slit
The Extreme ultraviolet Imaging Spectrometer (EIS) on board Hinode is the
first solar telescope to obtain wide slit spectral images that can be used for
detecting Doppler flows in transition region and coronal lines on the Sun and
to relate them to their surrounding small scale dynamics. We select EIS lines
covering the temperature range 6x10^4 K to 2x10^6 K that give spectrally pure
images of the Sun with the 40 arcsec slit. In these images Doppler shifts are
seen as horizontal brightenings. Inside the image it is difficult to
distinguish shifts from horizontal structures but emission beyond the image
edge can be unambiguously identified as a line shift in several lines separated
from others on their blue or red side by more than the width of the
spectrometer slit (40 pixels). In the blue wing of He II, we find a large
number of events with properties (size and lifetime) similar to the
well-studied explosive events seen in the ultraviolet spectral range.
Comparison with X-Ray Telescope (XRT) images shows many Doppler shift events at
the footpoints of small X-ray loops. The most spectacular event observed showed
a strong blue shift in transition region and lower corona lines from a small
X-ray spot that lasted less than 7 min. The emission appears to be near a cool
coronal loop connecting an X-ray bright point to an adjacent region of quiet
Sun. The width of the emission implies a line-of-sight velocity of 220 km/s. In
addition, we show an example of an Fe XV shift with a velocity about 120 km/s,
coming from what looks like a narrow loop leg connecting a small X-ray
brightening to a larger region of X-ray emission.Comment: 12 pages, 8 figures, to be published in Solar Physic
The Influence of Yoga-Based Programs on Risk Profiles in Adults with Type 2 Diabetes Mellitus: A Systematic Review
There is growing evidence that yoga may offer a safe and cost-effective intervention for Type 2 Diabetes mellitus (DM 2). However, systematic reviews are lacking. This article critically reviews the published literature regarding the effects of yoga-based programs on physiologic and anthropometric risk profiles and related clinical outcomes in adults with DM 2. We performed a comprehensive literature search using four computerized English and Indian scientific databases. The search was restricted to original studies (1970β2006) that evaluated the metabolic and clinical effects of yoga in adults with DM 2. Studies targeting clinical populations with cardiovascular disorders that included adults with comorbid DM were also evaluated. Data were extracted regarding study design, setting, target population, intervention, comparison group or condition, outcome assessment, data analysis and presentation, follow-up, and key results, and the quality of each study was evaluated according to specific predetermined criteria. We identified 25 eligible studies, including 15 uncontrolled trials, 6 non-randomized controlled trials and 4 randomized controlled trials (RCTs). Overall, these studies suggest beneficial changes in several risk indices, including glucose tolerance and insulin sensitivity, lipid profiles, anthropometric characteristics, blood pressure, oxidative stress, coagulation profiles, sympathetic activation and pulmonary function, as well as improvement in specific clinical outcomes. Yoga may improve risk profiles in adults with DM 2, and may have promise for the prevention and management of cardiovascular complications in this population. However, the limitations characterizing most studies preclude drawing firm conclusions. Additional high-quality RCTs are needed to confirm and further elucidate the effects of standardized yoga programs in populations with DM 2
Chapter 23: Climate change and Great Barrier Reef: industries and communities
Climate change is driving shifts in environmental conditions that, together with other human
pressures, are impacting the Great Barrier Reef (GBR). Individuals, communities, and industries in the
GBR catchment depend directly or indirectly on the GBR for ecosystem goods and services. These take
the form of direct economic benefits (including commercial activities such as tourism and fishing),
social services (including recreational activities and cultural linkages) and environmental services
(including shoreline protection from barrier reefs and mangrove stands).This is Chapter 23 of Climate change and the Great Barrier Reef: a vulnerability assessment. The entire book can be found at http://hdl.handle.net/11017/13
Emergency department waiting room nurses in practice: An observational study
Β© 2017 John Wiley & Sons Ltd Aims and objectives: To identify the activities and behaviours of waiting room nurses in emergency department settings. Background: Emergency care has expanded into waiting rooms in some emergency departments. Often viewed as an adjunct to triage, the aim of waiting room nurses is to commence care early, reassess patients and improve communication between patients, families and staff. There is however a paucity of literature relating to waiting room nurses, especially in relation to their current activities and behaviours. Design and methods: Part of a larger exploratory sequential mixed methods designed study. This phase used a nonparticipant observer role to observe waiting room nurses in their natural setting undertaking normal care and responsibilities. One observer, using a tool and reflective journal, collected data on participant interactions, processes and practices on eight waiting room nurses over 13 episodes of observation (total 65Β hr:50Β min) in two emergency departments. Data analysis used descriptive statistics and thematic analysis. Results: Participants were observed to anticipate and prioritise to deliver holistic, patient-centred care in emergency department waiting rooms. Waiting room nurses had a varied and unpredictable workload, including facilitating the flow of patients from the waiting room. They contributed to patient safety in the waiting room, primarily by reassessing and detecting clinical deterioration. Conclusion: Further research into this role is required, including linking efficacy with experience of nurses, impact the role has on patient safety, and patient and family perceptions of the role. Relevance to clinical practice: Therapeutic engagement allowed waiting room nurses to reassure and calm patients and families, and deliver holistic, patient-centred care. Waiting room nurses contributed to patient safety in the waiting room, by promptly commencing episodes of care in the waiting room and through close monitoring and assessment to detect patient deterioration
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