2,055 research outputs found
Endogenous growth and recycling : a material balance approach
In this paper we analyze the importance of recycling in the strive for sustainable development. In contrast to former approaches we emphasize the role of the waste stock as a source of valuable inputs. We enhance a Romer (1990) type endogenous growth model by a material balance condition that re°ects the circulation of matter in the economy. DiŸerentiated intermediate products are produced from recycled waste and virgin resources. These material intermediates are then employed in the production of ¯nal output. They either end up as waste after consumption or are bound in the capital stock { depending on the utilization of the produced output. We show that, even in the absence of environmental policy, long-run development is sustainable in this economy. The intuition is, that, as waste is a valuable resource in our model, not recycling part of it, cannot be optimal in the long-run.non-renewable resources, recycling, endogenous growth, sustainable development
Creation of strange matter at low initial m/T
We demonstrate that the creation of strange matter is conceivable in the midrapidity region of heavy ion collisions at Brookhaven RHIC and CERN LHC. A finite net-baryon density, abundant (anti)strangeness production, as well as strong net-baryon and net-strangeness fluctuations, provide suitable initial conditions for the formation of strangelets or metastable exotic multistrange ( baryonic) objects. Even at very high initial entropy per baryon SyAinit ÂŻ 500 and low initial baryon numbers of Ainit B ÂŻ 30 a quark-gluon-plasma droplet can immediately charge up with strangeness and accumulate net-baryon number. PACS numbers: 25.75.Dw, 12.38.Mh, 24.85.
Lyot-based Low Order Wavefront Sensor: Implementation on the Subaru Coronagraphic Extreme Adaptive Optics System and its Laboratory Performance
High throughput, low inner working angle (IWA) phase masks coronagraphs are
essential to directly image and characterize (via spectroscopy) earth-like
planets. However, the performance of low-IWA coronagraphs is limited by
residual pointing errors and other low-order modes. The extent to which
wavefront aberrations upstream of the coronagraph are corrected and calibrated
drives coronagraphic performance. Addressing this issue is essential for
preventing coronagraphic leaks, thus we have developed a Lyot-based low order
wave front sensor (LLOWFS) to control the wavefront aberrations in a
coronagraph. The LLOWFS monitors the starlight rejected by the coronagraphic
mask using a reflective Lyot stop in the downstream pupil plane. The early
implementation of LLOWFS at LESIA, Observatoire de Paris demonstrated an open
loop measurement accuracy of 0.01 lambda/D for tip-tilt at 638 nm when used in
conjunction with a four quadrant phase mask (FQPM) in the laboratory. To
further demonstrate our concept, we have installed the reflective Lyot stops on
the Subaru Coronagraphic Extreme AO (SCExAO) system at the Subaru Telescope and
modified the system to support small IWA phase mask coronagraphs (< 1 lambda/D)
on-sky such as FQPM, eight octant phase mask, vector vortex coronagraph and the
phase induced amplitude apodization complex phase mask coronagraph with a goal
of obtaining milli arc-second pointing accuracy. Laboratory results have shown
the measurement of tip, tilt, focus, oblique and right astigmatism at 1.55 um
for the vector vortex coronagraph. Our initial on-sky result demonstrate the
closed loop accuracy of < 7 x 10-3 lambda/D at 1.6 um for tip, tilt and focus
aberrations with the vector vortex coronagraph.Comment: 9 pages, 9 Figures, Proc. of SPIE Astronomical Telescopes +
Instrumentation 201
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Validation of the PILL-5: A 5-Item Patient Reported Outcome Measure for Pill Dysphagia.
Objectives: Pill dysphagia is common and costly with a significant risk of pill retention, caustic injury, and poor medication compliance. The purpose of this investigation was to determine the validity and reliability of the PILL-5, a self-administered patient reported outcome measure (PROM) to quantify the degree of pill (tablet and capsule) dysphagia. The PILL-5 is a 5-item questionnaire with a maximum symptom score of 20. Methods: The PILL-5 was administered to 190 patients with dysphagia referred for videofluoroscopic esophagography (VFE). Construct validity was assessed by comparing PILL-5 composite scores to delayed barium tablet transit on VFE. Normative data was obtained by administering the instrument to a cohort of healthy community based volunteers. Internal consistency was assessed with the Cronbach alpha. Test/retest reliability was determined by administering the instrument to the same cohort of patients at two time points. Results: The mean PILL-5 was 5.6 (±4.9) for persons with dysphagia and 1.6 (±2.7) for healthy volunteers (p < 0.001). The internal consistency of the instrument was high (Cronbach alpha = 0.85). The mean PILL-5 was 4.3 (±4.1) for patients with normal transit and 7.6 (±5.3) for patients with delayed barium tablet transit on esophagography, indicating excellent criterion based validity (p < 0.001). Reproducibility was high with an intraclass correlation coefficient of 0.83 (p < 0.001). Conclusions: Healthy individuals report some degree of swallowing difficulty with pills. Normative data suggest that a PILL-5 > 6 is abnormal (mean + 2 SD). The instrument demonstrated excellent criterion based validity and reliability. The PILL-5 is the first validated patient reported outcome measure for pill dysphagia
On-sky demonstration of low-order wavefront sensing and control with focal plane phase mask coronagraphs
The ability to characterize exoplanets by spectroscopy of their atmospheres
requires direct imaging techniques to isolate planet signal from the bright
stellar glare. One of the limitations with the direct detection of exoplanets,
either with ground- or space-based coronagraphs, is pointing errors and other
low-order wavefront aberrations. The coronagraphic detection sensitivity at the
diffraction limit therefore depends on how well low-order aberrations upstream
of the focal plane mask are corrected. To prevent starlight leakage at the
inner working angle of a phase mask coronagraph, we have introduced a
Lyot-based low-order wavefront sensor (LLOWFS), which senses aberrations using
the rejected starlight diffracted at the Lyot plane. In this paper, we present
the implementation, testing and results of LLOWFS on the Subaru Coronagraphic
Extreme Adaptive Optics system (SCExAO) at the Subaru Telescope.
We have controlled thirty-five Zernike modes of a H-band vector vortex
coronagraph in the laboratory and ten Zernike modes on sky with an integrator
control law. We demonstrated a closed-loop pointing residual of 0.02 mas in the
laboratory and 0.15 mas on sky for data sampled using the minimal 2-second
exposure time of the science camera. We have also integrated the LLOWFS in the
visible high-order control loop of SCExAO, which in closed-loop operation has
validated the correction of the non-common path pointing errors between the
infrared science channel and the visible wavefront sensing channel with
pointing residual of 0.23 mas on sky.Comment: 12 pages, 15 figures, Accepted and scheduled for publication in
September 2015 issue of the PAS
Nano-optomechanical measurement in the photon counting regime
Optically measuring in the photon counting regime is a recurrent challenge in
modern physics and a guarantee to develop weakly invasive probes. Here we
investigate this idea on a hybrid nano-optomechanical system composed of a
nanowire hybridized to a single Nitrogen-Vacancy (NV) defect. The vibrations of
the nanoresonator grant a spatial degree of freedom to the quantum emitter and
the photon emission event can now vary in space and time. We investigate how
the nanomotion is encoded on the detected photon statistics and explore their
spatio-temporal correlation properties. This allows a quantitative measurement
of the vibrations of the nanomechanical oscillator at unprecedentedly low light
intensities in the photon counting regime when less than one photon is detected
per oscillation period, where standard detectors are dark-noise-limited. These
results have implications for probing weakly interacting nanoresonators, for
low temperature experiments and for investigating single moving markers
Search for production of strangelets in quark matter using particle correlations
We present a new technique for observing the strangelet production in quark matter based on unlike particle correlations. A simulation is presented with a two-phase thermodynamical model
Approach for tuberculosis-associated immune reconstitution inflammatory syndrome in an HIV-negative patient
A male refugee from the Middle East was diagnosed with pulmonary tuberculosis and Pottâs disease with paravertebral abscess. After starting the standard regimen, the sputum culture converted to negative and the patientâs general condition improved. Six weeks later, the patient presented with clinical worsening of known symptoms, new appearance of focal neurological deficits and progress of radiological features showing progression of the paravertebral abscess. Immune reconstitution inflammatory syndrome with Mycobacterium tuberculosis (TB-IRIS) was presumed, and treatment with high-dose steroids was started. Due to recurrent relapses while tapering, corticosteroids had to be given over a prolonged period. After treatment completion, the patient was in a good general condition, abscesses had decreased and neurological deficits were in complete remission. This case presents the rare manifestation of TB-IRIS in HIV-negative patients and its management in a high-income country
Relationship intention and relationship quality as predictors of clothing retail customers' loyalty
Retailers endeavour to establish and maintain strong relationships with customers in order to build customer loyalty. Unfortunately, such endeavours are not always successful as not all retail customers reciprocate retailersâ relationship efforts. Customersâ intentions to engage in relationships with retailers (i.e. relationship intentions) should thus be the starting point in building customer loyalty. Moreover, customersâ perceptions of the strength of their relationship with a retailer (i.e. relationship quality) should also be considered when building customer loyalty. The purpose of this study is to determine whether clothing retail customersâ relationship intentions and relationship quality, individually and in combination, predict their loyalty to clothing retailers. Data were collected from 511 respondents in South Africaâs greater Tshwane metropolitan area. From a hierarchical multiple regression analysis, it was found that clothing retail customersâ relationship intentions and relationship quality are individually, and in combination, predictors of their loyalty to the retailer. Results furthermore indicate that relationship quality mediates the relationship between relationship intention and customer loyalty. The findings highlight the importance of first determining customersâ relationship intentions, and then reinforcing positive perceptions of relationship quality when building customer loyalty.http://www.tandfonline.com/loi/rirr20hj2019Marketing Managemen
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