191 research outputs found
Injuries, Ill-Health and Fatalities in White Water Rafting and White Water Paddling
White water (WW) activities such as paddling (canoeing and kayaking) and rafting are popular sports for recreational and professional participants. An increase in participation has been seen worldwide. However, these activities come with a risk of injury and even death if not conducted safely. A review was conducted to identify the types of injuries and ill-health that occur as a result of these activities. Injury and fatality rates were assessed to establish the risk attributed to these activities. Web of Science, PubMed, Ergonomics Abstracts and PsycINFO databases were searched and a total of 16 published articles were identified and reviewed. The shoulders and back were the most vulnerable sites for injury in WW paddling. Injuries to the face and lower limbs were most common in WW rafters. However, injury rates are low and estimates are discussed. Due to different methods used across the studies, the reported injury rates are not comparable. This review identified three illnesses incurred through WW activities. There may be more but these are not currently reported in the literature. A relative paucity of studies regarding injuries and fatalities in WW activities was identified. Directions for future research are suggested and discussed
Augmenting the Eye of the Beholder: Exploring the Strategic Potential of Augmented Reality to Enhance Online Service Experiences
Driven by the proliferation of augmented reality (AR) technologies, many firms are pursuing a strategy of service augmentation to enhance customersâ online service experiences. Drawing on situated cognition theory, the authors show that AR - based service augmentation enhances customer value perceptions by simultaneously providing simulated physical control and environmental embedding. The resulting authentic situated experience, manifested in a feeling of spatial presence, funct ions as a mediator and also predicts customer decision comfort. Furthermore, the effect of spatial presence on utilitarian value perceptions is greater for customers who are disposed toward verbal rather than visual information processing, and the positive effect on decision comfort is attenuated by customersâ privacy concerns
Apnea of prematurity: from cause to treatment
Apnea of prematurity (AOP) is a common problem affecting premature infants, likely secondary to a âphysiologicâ immaturity of respiratory control that may be exacerbated by neonatal disease. These include altered ventilatory responses to hypoxia, hypercapnia, and altered sleep states, while the roles of gastroesophageal reflux and anemia remain controversial. Standard clinical management of the obstructive subtype of AOP includes prone positioning and continuous positive or nasal intermittent positive pressure ventilation to prevent pharyngeal collapse and alveolar atelectasis, while methylxanthine therapy is a mainstay of treatment of central apnea by stimulating the central nervous system and respiratory muscle function. Other therapies, including kangaroo care, red blood cell transfusions, and CO2 inhalation, require further study. The physiology and pathophysiology behind AOP are discussed, including the laryngeal chemoreflex and sensitivity to inhibitory neurotransmitters, as are the mechanisms by which different therapies may work and the potential long-term neurodevelopmental consequences of AOP and its treatment
Updated measurements of exclusive J/Ï and Ï(2S) production cross-sections in pp collisions at âs = 7 TeV
The differential cross-section as a function of rapidity has been measured for the exclusive production of J/Ï and Ï(2S) mesons in protonâproton collisions at âs = 7 TeV, using data collected by the LHCb experiment, corresponding to an integrated luminosity of 930 pbâ1. The cross-sections times branching fractions to two muons having pseudorapidities between 2.0 and 4.5 are measured to be where the first uncertainty is statistical and the second is systematic. The measurements agree with next-to-leading order QCD predictions as well as with models that include saturation effects
Observation of B+c â D0K+ decays
Using proton-proton collision data corresponding to an integrated luminosity of 3.0 fbâ1, recorded by
the LHCb detector at center-of-mass energies of 7 and 8 TeV, the B+
c â D0K+ decay is observed with a
statistical significance of 5.1 standard deviations. By normalizing to B+ â DÂŻ 0Ï+ decays, a measurement of
the branching fraction multiplied by the production rates for B+
c relative to B+ mesons in the LHCb
acceptance is obtained, R
D
0
K
=
(
f
c
/
f
u
)
Ă
B
(
B
+
c
â
D
0
K
+
)
=
(
9.
3
+
2.8
â
2.5
±
0.6
)
Ă
10
â
7, where the first
uncertainty is statistical and the second is systematic. This decay is expected to proceed predominantly
through weak annihilation and penguin amplitudes, and is the first B+
c decay of this nature to be observed
Measurement of the B_{s}^{0}âÎŒ^{+}ÎŒ^{-} Branching Fraction and Effective Lifetime and Search for B^{0}âÎŒ^{+}ÎŒ^{-} Decays.
A search for the rare decays B_{s}^{0}âÎŒ^{+}ÎŒ^{-} and B^{0}âÎŒ^{+}ÎŒ^{-} is performed at the LHCb experiment using data collected in pp collisions corresponding to a total integrated luminosity of 4.4ââfb^{-1}. An excess of B_{s}^{0}âÎŒ^{+}ÎŒ^{-} decays is observed with a significance of 7.8 standard deviations, representing the first observation of this decay in a single experiment. The branching fraction is measured to be B(B_{s}^{0}âÎŒ^{+}ÎŒ^{-})=(3.0±0.6_{-0.2}^{+0.3})Ă10^{-9}, where the first uncertainty is statistical and the second systematic. The first measurement of the B_{s}^{0}âÎŒ^{+}ÎŒ^{-} effective lifetime, Ï(B_{s}^{0}âÎŒ^{+}ÎŒ^{-})=2.04±0.44±0.05ââps, is reported. No significant excess of B^{0}âÎŒ^{+}ÎŒ^{-} decays is found, and a 95% confidence level upper limit, B(B^{0}âÎŒ^{+}ÎŒ^{-})<3.4Ă10^{-10}, is determined. All results are in agreement with the standard model expectations
Multi-messenger observations of a binary neutron star merger
On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transientâs position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta
Search for gravitational waves from Scorpius X-1 in the second Advanced LIGO observing run with an improved hidden Markov model
We present results from a semicoherent search for continuous gravitational waves from the low-mass x-ray binary Scorpius X-1, using a hidden Markov model (HMM) to track spin wandering. This search improves on previous HMM-based searches of LIGO data by using an improved frequency domain matched filter, the J-statistic, and by analyzing data from Advanced LIGO's second observing run. In the frequency range searched, from 60 to 650 Hz, we find no evidence of gravitational radiation. At 194.6 Hz, the most sensitive search frequency, we report an upper limit on gravitational wave strain (at 95% confidence) of h095%=3.47Ă10-25 when marginalizing over source inclination angle. This is the most sensitive search for Scorpius X-1, to date, that is specifically designed to be robust in the presence of spin wandering. © 2019 American Physical Society
Search for gravitational waves from Scorpius X-1 in the second Advanced LIGO observing run with an improved hidden Markov model
We present results from a semicoherent search for continuous gravitational waves from the low-mass x-ray binary Scorpius X-1, using a hidden Markov model (HMM) to track spin wandering. This search improves on previous HMM-based searches of LIGO data by using an improved frequency domain matched filter, the J-statistic, and by analyzing data from Advanced LIGOâs second observing run. In the frequency range searched, from 60 to 650 Hz, we find no evidence of gravitational radiation. At 194.6 Hz, the most sensitive search frequency, we report an upper limit on gravitational wave strain (at 95% confidence) of h95%0=3.47Ă10â25 when marginalizing over source inclination angle. This is the most sensitive search for Scorpius X-1, to date, that is specifically designed to be robust in the presence of spin wandering
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