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https://www.readbyqxmd.com/read/28239851/sawfishes-stealth-revealed-using-computational-fluid-dynamics
#1
D R Bradney, A Davidson, S P Evans, B E Wueringer, D L Morgan, P D Clausen
Detailed computational fluid dynamics simulations for the rostrum of three species of sawfish (Pristidae) revealed that negligible turbulent flow is generated from all rostra during lateral swipe prey manipulation and swimming. These results suggest that sawfishes are effective stealth hunters that may not be detected by their teleost prey's lateral line sensory system during pursuits. Moreover, during lateral swipes, the rostra were found to induce little velocity into the surrounding fluid. Consistent with previous data of sawfish feeding behaviour, these data indicate that the rostrum is therefore unlikely to be used to stir up the bottom to uncover benthic prey...
February 27, 2017: Journal of Fish Biology
https://www.readbyqxmd.com/read/28238498/legal-social-ethical-and-medical-perspectives-on-the-care-of-the-statutory-rape-adolescent-in-the-emergency-department
#2
Shiu-Lin Tsai, Elvira Acosta, Toni Cardenas, Jeremy K Sigall, Kevin Van Geem
Rapes involving adolescents who present to the emergency department (ED) are fraught with ethical and legal complexities and are often emotionally turbulent for patients, their families, and medical providers. Management requires a thoughtful approach from multiple standpoints, including legal, psychosocial, ethical, and medical ones. However, there is no standardized sexual assault education for emergency medicine residents, and management practices vary widely.(1,2) We present a hypothetical statutory rape case based on real cases that occurred in New York City and bring together the perspectives of an attorney on the legal parameters, two social workers on the psychosocial issues, an ethicist on the moral considerations, and a pediatric emergency physician-who is also a sexual assault forensic examiner-on the medical treatments...
February 23, 2017: Annals of Emergency Medicine
https://www.readbyqxmd.com/read/28236730/development-of-a-highly-sensitive-radon-222-amplifier-hisra-for-low-level-atmospheric-measurements
#3
Sylvain Topin, Patrick Richon, Vincent Thomas, Claire Gréau, Julie Pujos, Julien Moulin, Alexandre Hovesepian, Ludovic Deliere
Radon ((222)Rn), a radioactive gas with a half-life of 3.82 days, is continuously emanated from soil, rocks, and water by the radioactive decay of (226)Ra. Radon-222 is released from the ground into the atmosphere, where it is transported mainly by turbulent diffusion or convection. For precise measurement of radon-222 atoms in the atmosphere, the detectors typically used present a small volume or surface area and are therefore not very sensitive, especially for online measurements and short sample intervals (<1 h)...
February 22, 2017: Journal of Environmental Radioactivity
https://www.readbyqxmd.com/read/28230076/adaptive-free-space-optical-communications-through-turbulence-using-self-healing-bessel-beams
#4
Shuhui Li, Jian Wang
We present a scheme to realize obstruction- and turbulence-tolerant free-space orbital angular momentum (OAM) multiplexing link by using self-healing Bessel beams accompanied by adaptive compensation techniques. Compensation of multiple 16-ary quadrature amplitude modulation (16-QAM) data carrying Bessel beams through emulated atmospheric turbulence and obstructions is demonstrated. The obtained experimental results indicate that the compensation scheme can effectively reduce the inter-channel crosstalk, improve the bit-error rate (BER) performance, and recuperate the nondiffracting property of Bessel beams...
February 23, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28227464/the-effect-of-the-aortic-valve-orientation-on-cavitation
#5
Peter Johansen, Brandon R Travis, Morten Smerup, Thomas Decker Christensen, Jonas Funder, Camilla Nyboe, Hans Nygaard, J Michael Hasenkam, Peter Johansen, Brandon R Travis, Morten Smerup, Thomas Decker Christensen, Jonas Funder, Camilla Nyboe, Hans Nygaard, J Michael Hasenkam, Brandon R Travis, Peter Johansen, Hans Nygaard, Morten Smerup, Jonas Funder, Camilla Nyboe, Thomas Decker Christensen, J Michael Hasenkam
When implanting a mechanical aortic valve the annulus orientation is important with respect to turbulence. However, the effect on cavitation has not yet been investigated. The aim of this study was to investigate how cavitation is influenced hereof in vivo. Three pigs were included in the study. An Omnicarbon 21mm valve equipped with a rotating mechanism enabling controlled rotation of the valve was implanted in aortic position. Under stable hemodynamic conditions, measurements were performed using a hydrophone positioned at the aortic root...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28224338/the-response-of-phosphorus-uptake-strategies-of-microcystis-aeruginosa-to-hydrodynamics-fluctuations
#6
Yue Zheng, Wujuan Mi, Yonghong Bi, Zhengyu Hu
The mechanisms of hydrodynamic fluctuation that affect cyanobacterial physiological aspects are still unclear. This study was conducted to screen the effects of hydrodynamic fluctuation on phosphorus (P) uptake by Microcystis aeruginosa. Four levels of circumfluence (0, 100, 200, and 300 rpm) and three concentrations of P (0.5, 2.0, and 5.0 mgL(-1)) were used, and the specific growth rate, cell viability, P uptake kinetic, and alkaline phosphatase activity (APA) were determined. Results showed that M. aeruginosa had a higher specific growth rate, cell viability, and P uptake rate at low and moderate circumfluence, APA increased with a decrease of the cellular P quota (Qp)...
February 21, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28217773/finding-food-how-marine-invertebrates-use-chemical-cues-to-track-and-select-food
#7
REVIEW
Michiya Kamio, Charles D Derby
Benthic marine invertebrates sense molecules from other organisms and use these molecules to find and evaluate the organisms as sources of food. These processes depend on the detection and discrimination of molecules carried in sea water around and in the mouths of these animals. To understand these processes, researchers have studied how molecules released from food distribute in the sea water as a plume, how animals respond to the plume, the molecular identity of the attractants in the plume, the effect of turbulence on food-searching success, and how animals evaluate the quality of food and make decisions to eat or not...
February 20, 2017: Natural Product Reports
https://www.readbyqxmd.com/read/28216243/effect-of-laminar-airflow-ventilation-on-surgical-site-infections-a-systematic-review-and-meta-analysis
#8
Peter Bischoff, N Zeynep Kubilay, Benedetta Allegranzi, Matthias Egger, Petra Gastmeier
BACKGROUND: The role of the operating room's ventilation system in the prevention of surgical site infections (SSIs) is widely discussed, and existing guidelines do not reflect current evidence. In this context, laminar airflow ventilation was compared with conventional ventilation to assess their effectiveness in reducing the risk of SSIs. METHODS: We searched MEDLINE, Embase, Cochrane Central Register of Controlled Trials, and WHO regional medical databases from Jan 1, 1990, to Jan 31, 2014...
February 16, 2017: Lancet Infectious Diseases
https://www.readbyqxmd.com/read/28211738/classes-of-hydrodynamic-and-magnetohydrodynamic-turbulent-decay
#9
Axel Brandenburg, Tina Kahniashvili
We perform numerical simulations of decaying hydrodynamic and magnetohydrodynamic turbulence. We classify our time-dependent solutions by their evolutionary tracks in parametric plots between instantaneous scaling exponents. We find distinct classes of solutions evolving along specific trajectories toward points on a line of self-similar solutions. These trajectories are determined by the underlying physics governing individual cases, while the infrared slope of the initial conditions plays only a limited role...
February 3, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28211730/kinetic-turbulence-in-relativistic-plasma-from-thermal-bath-to-nonthermal-continuum
#10
Vladimir Zhdankin, Gregory R Werner, Dmitri A Uzdensky, Mitchell C Begelman
We present results from particle-in-cell simulations of driven turbulence in magnetized, collisionless, and relativistic pair plasmas. We find that the fluctuations are consistent with the classical k_{⊥}^{-5/3} magnetic energy spectrum at fluid scales and a steeper k_{⊥}^{-4} spectrum at sub-Larmor scales, where k_{⊥} is the wave vector perpendicular to the mean field. We demonstrate the development of a nonthermal, power-law particle energy distribution f(E)∼E^{-α}, with an index α that decreases with increasing magnetization and increases with an increasing system size (relative to the characteristic Larmor radius)...
February 3, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28211703/collisional-scaling-of-the-energy-transfer-in-drift-wave-zonal-flow-turbulence
#11
B Schmid, P Manz, M Ramisch, U Stroth
The collisionality scaling of density and potential coupling together with zonal flow energy transfer and spectral power is investigated at the stellarator experiment TJ-K. With a poloidal probe array, consisting of 128 Langmuir probes, density and potential fluctuations are measured on four neighboring flux surfaces simultaneously over the complete poloidal circumference. By analyzing Reynolds stress and pseudo-Reynolds stress, it is found that, for increasing collisionality, the coupling between density and potential decreases which hinders the zonal flow drive...
February 3, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28208488/analysis-of-flame-acceleration-in-open-or-vented-obstructed-pipes
#12
Vitaly Bychkov, Jad Sadek, V'yacheslav Akkerman
While flame propagation through obstacles is often associated with turbulence and/or shocks, Bychkov et al. [V. Bychkov et al., Phys. Rev. Lett. 101, 164501 (2008)10.1103/PhysRevLett.101.164501] have revealed a shockless, conceptually laminar mechanism of extremely fast flame acceleration in semiopen obstructed pipes (one end of a pipe is closed; a flame is ignited at the closed end and propagates towards the open one). The acceleration is devoted to a powerful jet flow produced by delayed combustion in the spaces between the obstacles, with turbulence playing only a supplementary role in this process...
January 2017: Physical Review. E
https://www.readbyqxmd.com/read/28208477/bifurcation-induced-by-the-aspect-ratio-in-a-turbulent-von-k%C3%A3-rm%C3%A3-n-swirling-flow
#13
Olivier Liot, Javier Burguete
We evaluate the effect of the aspect ratio, i.e., the distance between the propellers H divided by the diameter D, on the slow dynamics of a von Kármán swirling flow driven by two propellers in a closed cylinder. We use a cell with a fixed diameter D but where the distance between the propellers can be turned continuously and where the inertia from the propellers can also be changed using different gears. No change on the dynamics is observed when the momentum of inertia is modified. Some dramatic changes of the shear layer position are observed modifying the aspect ratio Γ=H/D...
January 2017: Physical Review. E
https://www.readbyqxmd.com/read/28208331/reynolds-number-dependence-of-the-dimensionless-dissipation-rate-in-homogeneous-magnetohydrodynamic-turbulence
#14
Moritz Linkmann, Arjun Berera, Erin E Goldstraw
This paper examines the behavior of the dimensionless dissipation rate C_{ɛ} for stationary and nonstationary magnetohydrodynamic (MHD) turbulence in the presence of external forces. By combining with previous studies for freely decaying MHD turbulence, we obtain here both the most general model equation for C_{ɛ} applicable to homogeneous MHD turbulence and a comprehensive numerical study of the Reynolds number dependence of the dimensionless total energy dissipation rate at unity magnetic Prandtl number...
January 2017: Physical Review. E
https://www.readbyqxmd.com/read/28208327/issues-associated-with-galilean-invariance-on-a-moving-solid-boundary-in-the-lattice-boltzmann-method
#15
Cheng Peng, Nicholas Geneva, Zhaoli Guo, Lian-Ping Wang
In lattice Boltzmann simulations involving moving solid boundaries, the momentum exchange between the solid and fluid phases was recently found to be not fully consistent with the principle of local Galilean invariance (GI) when the bounce-back schemes (BBS) and the momentum exchange method (MEM) are used. In the past, this inconsistency was resolved by introducing modified MEM schemes so that the overall moving-boundary algorithm could be more consistent with GI. However, in this paper we argue that the true origin of this violation of Galilean invariance (VGI) in the presence of a moving solid-fluid interface is due to the BBS itself, as the VGI error not only exists in the hydrodynamic force acting on the solid phase, but also in the boundary force exerted on the fluid phase, according to Newton's Third Law...
January 2017: Physical Review. E
https://www.readbyqxmd.com/read/28207869/impact-of-wall-shear-stress-on-initial-bacterial-adhesion-in-rotating-annular-reactor
#16
Thibaut Saur, Emilie Morin, Frédéric Habouzit, Nicolas Bernet, Renaud Escudié
The objective of this study was to investigate the bacterial adhesion under different wall shear stresses in turbulent flow and using a diverse bacterial consortium. A better understanding of the mechanisms governing microbial adhesion can be useful in diverse domains such as industrial processes, medical fields or environmental biotechnologies. The impact of wall shear stress-four values ranging from 0.09 to 7.3 Pa on polypropylene (PP) and polyvinyl chloride (PVC)-was carried out in rotating annular reactors to evaluate the adhesion in terms of morphological and microbiological structures...
2017: PloS One
https://www.readbyqxmd.com/read/28206776/military-children-s-difficulty-with-reintegration-after-deployment-a-relational-turbulence-model-perspective
#17
Leanne K Knobloch, Lynne M Knobloch-Fedders, Jeremy B Yorgason, Aaron T Ebata, Patricia C McGlaughlin
This study drew on the relational turbulence model to investigate how the interpersonal dynamics of military couples predict parents' reports of the reintegration difficulty of military children upon homecoming after deployment. Longitudinal data were collected from 118 military couples once per month for 3 consecutive months after reunion. Military couples reported on their depressive symptoms, characteristics of their romantic relationship, and the reintegration difficulty of their oldest child. Results of dyadic growth curve models indicated that the mean levels of parents' depressive symptoms (H1), relationship uncertainty (H2), and interference from a partner (H3) were positively associated with parents' reports of military children's reintegration difficulty...
February 16, 2017: Journal of Family Psychology: JFP
https://www.readbyqxmd.com/read/28203207/morphotype-dependent-flow-characteristics-in-bicuspid-aortic-valve-ascending-aortas-a-benchtop-particle-image-velocimetry-study
#18
Andrew McNally, Ashish Madan, Philippe Sucosky
The bicuspid aortic valve (BAV) is a major risk factor for secondary aortopathy such as aortic dilation. The heterogeneous BAV morphotypes [left-right-coronary cusp fusion (LR), right-non-coronary cusp fusion (RN), and left-non-coronary cusp fusion (LN)] are associated with different dilation patterns, suggesting a role for hemodynamics in BAV aortopathogenesis. However, assessment of this theory is still hampered by the limited knowledge of the hemodynamic abnormalities generated by the distinct BAV morphotypes...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28198950/there-is-much-to-learn-from-this-turbulent-year-that-now-comes-to-an-end
#19
EDITORIAL
Maria Amélia de Campos Oliveira, Emiko Yoshikawa Egry
No abstract text is available yet for this article.
November 2016: Revista da Escola de Enfermagem da U S P
https://www.readbyqxmd.com/read/28198849/free-space-active-polarimetric-imager-operating-at-1-55%C3%A2-%C3%A2-%C3%AE-m-by-orthogonality-breaking-sensing
#20
Francois Parnet, Julien Fade, Noé Ortega-Quijano, Goulc'hen Loas, Ludovic Frein, Mehdi Alouini
We report the design and optimization of an active polarimetric imaging demonstrator operating at 1.55 μm that is based on the orthogonality breaking technique. It relies on the use of a fibered dual-frequency dual-polarization source raster scanned over the scene. A dedicated opto-electronic detection chain is developed to demodulate the optical signal backscattered at each location of the scene in real time, providing multivariate polarimetric image data in one single scan with limited acquisition time. We experimentally show on a homemade scene that contrast maps can be built to reveal hidden dichroic objects over a depolarizing background, as well as their orientation...
February 15, 2017: Optics Letters
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