1,023 research outputs found
Zipline-Related Injuries Treated in US EDs, 1997-2012
Purpose
To investigate the epidemiology of zipline-related injuries in the United States. Basic Procedures
The National Electronic Injury Surveillance System database was used to examine non-fatal zipline-related injuries treated in US emergency departments (EDs) from 1997 through 2012. Sample weights were applied to calculate national estimates. Main Findings
From 1997 through 2012, an estimated 16850 (95% CI, 13188-20512) zipline-related injuries were treated in US EDs. The annual injury rate per 1 million population increased by 52.3% from 7.64 (95% CI, 4.86-10.42) injuries in 2009 (the first year with a stable annual estimate) to 11.64 (95% CI, 7.83-15.45) injuries in 2012. Patients aged 0-9 years accounted for 45.0% of injuries, females made up 53.1% of injuries, and 11.7% of patients required hospitalization. Fractures accounted for the largest proportion of injuries (46.7%), and the upper extremities were the most commonly injured body region (44.1%). Falls were the most common mechanism of injury, accounting for 77.3% of injuries. Among cases where the location of the injury event was known, 30.8% of injuries occurred in a residential setting and 69.2% occurred in a public place. Principal Conclusions
This study is the first to characterize the epidemiology of zipline-related injuries using a nationally representative database. The rapid increase in zipline-related injuries in recent years suggests the need for additional safety guidelines and regulations. Commercial ziplines and publicly accessible non-commercial ziplines should be subject to uniform safety standards in all states and jurisdictions across the US, and homemade ziplines should not be used
-Enhanced Imaging of Molecules in an Optical Trap
We report non-destructive imaging of optically trapped calcium monofluoride
(CaF) molecules using in-situ -enhanced gray molasses cooling.
times more fluorescence is obtained compared to destructive on-resonance
imaging, and the trapped molecules remain at a temperature of
. The achieved number of scattered photons makes possible
non-destructive single-shot detection of single molecules with high fidelity.Comment: 6 pages, 4 figure
An Optical Tweezer Array of Ultracold Molecules
Arrays of single ultracold molecules promise to be a powerful platform for
many applications ranging from quantum simulation to precision measurement.
Here we report on the creation of an optical tweezer array of single ultracold
CaF molecules. By utilizing light-induced collisions during the laser cooling
process, we trap single molecules. The high densities attained inside the
tweezer traps have also enabled us to observe in the absence of light
molecule-molecule collisions of laser cooled molecules for the first time
Parallel quantized charge pumping
Two quantized charge pumps are operated in parallel. The total current
generated is shown to be far more accurate than the current produced with just
one pump operating at a higher frequency. With the application of a
perpendicular magnetic field the accuracy of quantization is shown to be 20
ppm for a current of pA. The scheme for parallel pumping presented in
this work has applications in quantum information processing, the generation of
single photons in pairs and bunches, neural networking and the development of a
quantum standard for electrical current. All these applications will benefit
greatly from the increase in output current without the characteristic decrease
in accuracy as a result of high-frequency operation
One dimensional magneto-optical compression of a cold CaF molecular beam
We demonstrate with a RF-MOT the one dimensional, transverse magneto-optical
compression of a cold beam of calcium monofluoride (CaF). By continually
alternating the magnetic field direction and laser polarizations of the
magneto-optical trap, a photon scattering rate of 0.4 MHz is
achieved. A 3D model for this RF-MOT, validated by agreement with data,
predicts a 3D RF-MOT capture velocity for CaF of 5 m/s
Laser slowing of CaF molecules to near the capture velocity of a molecular MOT
Laser slowing of CaF molecules down to the capture velocity of a
magneto-optical trap (MOT) for molecules is achieved. Starting from a two-stage
buffer gas beam source, we apply frequency-broadened "white-light" slowing and
observe approximately 6x10^4 CaF molecules with velocities near 10\,m/s. CaF is
a candidate for collisional studies in the mK regime. This work represents a
significant step towards magneto-optical trapping of CaF
Infinite dimensional non-positively curved symmetric spaces of finite rank
This paper concerns a study of three families of non-compact type symmetric
spaces of infinite dimension. Although they have infinite dimension they have
finite rank. More precisely, we show they have finite telescopic dimension. We
also show the existence of Furstenberg maps for some group actions on these
spaces. Such maps appear as a first step toward superrigidity results.Comment: Some references have been adde
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