Prediction of net bedload transport rates obtained in oscillating water tunnels and applicability to real surf zone waves

Experimental studies of sediment transport rates due to near shore waves are often conducted in oscillating water tunnels (OWTs). In an OWT, the oscillatory motion produced by the piston propagates almost instantaneously along the entire tunnel. Consequently, unlike the wave motion in the sea or in a wave flume, flow in an OWT is uniform along the tunnel, and second - order wave propagation effects (such as Longuet - Higgins's streaming) are absent. The effect of these hydrodynamic differences between OWT and sea waves on sediment transport rates has generally been neglected. In this paper we present a simple, practical formulation to evaluate bed shear stresses and bed load transport rates due to asymmetric and skewed waves plus a current in an OWT, based on fitting the exact results of a rigorous, analytical model of the OWT wave - current boundary layer. By then accounting for real wave effects we find that wave propagation significantly affects the predicted period - averaged net sediment transport rates. Such real wave effects can therefore not be neglected when comparing near shore transport models with OWT data.Singapore–MIT Alliance for Research and Technology ((SMART) Center for Environmental Sensing and Modeling)Singapore. National Research Foundatio

Moving embedded lattice solitons

It was recently proved that isolated unstable "embedded lattice solitons" (ELS) may exist in discrete systems. The discovery of these ELS gives rise to relevant questions such as the following: are there continuous families of ELS?, can ELS be stable?, is it possible for ELS to move along the lattice?, how do ELS interact?. The present work addresses these questions by showing that a novel differential-difference equation (a discrete version of a complex mKdV equation) has a two-parameter continuous family of exact ELS. The numerical tests reveal that these solitons are stable and robust enough to withstand collisions. The model may apply to the description of a Bose-Einstein condensate with dipole-dipole interactions between the atoms, trapped in a deep optical-lattice potential.Comment: 13 pages, 11 figure

Photon emission as a source of coherent behaviour of polaritons

We show that the combined effect of photon emission and Coulomb interactions may drive an exciton-polariton system towards a dynamical coherent state, even without phonon thermalization or any other relaxation mechanism. Exact diagonalization results for a finite system (a multilevel quantum dot interacting with the lowest energy photon mode of a microcavity) are presented in support to this statement

Electrochemical reduction of carbamazepine in ethanol and water solutions using a glassy carbon electrode

The electrochemical reduction of carbamazepine in ethanol and water using a glassy carbon electrode has been studied. In all experimental conditions of scan rate and concentration of carbamazepine an irreversible cathodic wave was observed by cyclic voltammetry (CV). Electrochemical parameters and a plausible EqC mechanism have been reported from the electrochemical measurements and digital simulation. The values of thermodynamic E1/2 were correlated with solvent polarity parameters that it can be interesting for biological, pharmaceutical and forensic purposes. Limits of Detection (LOD) for DPV are 1.1 and 9.0 g/mL (4.65x10-6 and 3.81x10-5 M) in ethanol and water, respectively. The precision and recoveries obtained for tablets and plasma samples showed that the method could be successfully used for analysis

Development of a species-specific coproantigen ELISA for human taenia solium taeniasis

Taenia solium causes human neurocysticercosis and is endemic in underdeveloped countries where backyard pig keeping is common. Microscopic fecal diagnostic methods for human T. solium taeniasis are not very sensitive, and Taenia saginata and Taenia solium eggs are indistinguishable under the light microscope. Coproantigen (CoAg) ELISA methods are very sensitive, but currently only genus (Taenia) specific. This paper describes the development of a highly species-specific coproantigen ELISA test to detect T. solium intestinal taeniasis. Sensitivity was maintained using a capture antibody of rabbit IgG against T. solium adult whole worm somatic extract, whereas species specificity was achieved by utilization of an enzyme-conjugated rabbit IgG against T. solium adult excretory-secretory (ES) antigen. A known panel of positive and negative human fecal samples was tested with this hybrid sandwich ELISA. The ELISA test gave 100% specificity and 96.4% sensitivity for T. solium tapeworm carriers (N = 28), with a J index of 0.96. This simple ELISA incorporating anti-adult somatic and anti-adult ES antibodies provides the first potentially species-specific coproantigen test for human T. solium taeniasis

Star Formation Under the Outflow: The Discovery of a Non-Thermal Jet from OMC-2 FIR 3 and its Relationship to the Deeply Embedded FIR 4 Protostar

We carried out multiwavelength (0.7-5 cm), multiepoch (1994-2015) Very Large Array (VLA) observations toward the region enclosing the bright far-IR sources FIR 3 (HOPS 370) and FIR 4 (HOPS 108) in OMC-2. We report the detection of 10 radio sources, seven of them identified as young stellar objects. We image a well-collimated radio jet with a thermal free-free core (VLA 11) associated with the Class I intermediate-mass protostar HOPS 370. The jet presents several knots (VLA 12N, 12C, 12S) of non-thermal radio emission (likely synchrotron from shock-accelerated relativistic electrons) at distances of ~7,500-12,500 au from the protostar, in a region where other shock tracers have been previously identified. These knots are moving away from the HOPS 370 protostar at ~ 100 km/s. The Class 0 protostar HOPS 108, which itself is detected as an independent, kinematically decoupled radio source, falls in the path of these non-thermal radio knots. These results favor the previously proposed scenario where the formation of HOPS 108 has been triggered by the impact of the HOPS 370 outflow with a dense clump. However, HOPS 108 presents a large proper motion velocity of ~ 30 km/s, similar to that of other runaway stars in Orion, whose origin would be puzzling within this scenario. Alternatively, an apparent proper motion could result because of changes in the position of the centroid of the source due to blending with nearby extended emission, variations in the source shape, and /or opacity effects.Comment: 16 pages, 4 figures, accepted for publication in The Astrophysical Journa

A GEANT4 Study of a Gamma-ray Collimation Array

Proton beam therapy uses high-energy protons to destroy cancer cells which are still uncertain about where in the body they hit. A possible way to answer this question is to detect the gamma rays produced during the irradiation and determine where in the body they are produced. This work investigates the use of collimators to determine where the proton interactions occur. GEANT4 is used to simulate the gamma production of a source interacting with a collimator. Each event simulates a number of gammas obtained as a function of the position along the detector. Repeating for different collimator configurations can thus help determine the best characteristics of a detector device

Association Between Single-Leg Agility and Single-Leg Vertical Jumping Performance in Active Adults

The vertical jump is crucial in sports and indicates lower body explosiveness. Additionally, vertical jumping requires landing bilaterally or unilaterally. PURPOSE: To determine any differences in unilateral vertical jump performance when landing unilaterally or bilaterally. METHODS: Thirty recreationally trained individuals (age = 23.5 ± 2.2 years) performed three trials of vertical jumps under four different conditions in random order (unilateral-left vertical jump with bilateral landing, unilateral-right vertical jump with bilateral landing, unilateral-left vertical jump with ipsilateral landing, and unilateral-right vertical jump with ipsilateral landing). Kinetic data (peak force, relative peak force, peak power, and relative peak power) was obtained from all jumps at 1000 Hz sampling rate. The average score between trials for the vertical jump were used for statistical analysis in SPSS 25. Independent T-tests were used to find differences in vertical jump measures depending on landing condition with p-value at 0.05. RESULTS: No significant differences between limbs in jump height (Right = 0.08 cm ± 0.04; Left cm = 0.11 ± 0.05), peak force (Right = 473.3 N ± 135.6; Left = 600.1 N ± 182.6), relative peak force (Right = 6.8 N*kg ± 2.6; Left = 7.8 N*kg ± 1.9), peak power (Right = 1505.4 W ± 524.5; Left = 1934.9 W ± 771.9), and relative peak power (Right = 21.3 W*kg ± 7.2; Left = 25.5 W*kg ± 5.8) during unilateral vertical jumps between the landing conditions (p \u3e 0.05). CONCLUSION: It appears that landing conditions do not affect unilateral jump performance in recreationally trained athletes