Density- and wind-driven lateral circulation and the associated transport of sediments in idealized partially mixed estuaries

Lateral circulation and the associated transport of sediments in idealized partially mixed estuaries are investigated using a three-dimensional, hydrostatic, primitive equation numerical model (ROMS). The model simulates a straight estuarine channel with a triangular cross-section. Attention is focused on lateral density (salinity) gradients, the major driving force for lateral circulation. Lateral salinity gradients can result from boundary mixing on a slope and differential advection of axial salinity gradients. Without wind forcing, the numerical experiments suggest that boundary mixing on a slope can drive significant lateral circulation when the water column is stratified. Boundary mixing is at least as important as differential advection for the modeled scenarios, when the two mechanisms are evaluated using the salt balance equation. Sediments are eroded in the channel and preferentially deposited on the right slope (looking seaward), mainly due to tidal pumping. Both stratification and axial salt transport show strong responses to axial wind forcing. While stratification is always reduced by up-estuary winds, stratification shows an increase-to-decrease transition as down-estuary wind stress increases, due to the competition between wind-induced straining of the axial salinity gradient and direct wind mixing. A horizontal Richardson number modified to include wind straining/mixing is shown to reasonably represent the transition. A regime classification diagram is proposed. Axial winds also exert important controls on lateral circulation. When the water column mixes vertically, surface Ekman transport is not a significant contributor to lateral circulation. Instead, wind-induced differential advection of the axial salinity gradient establishes lateral salinity gradients that in turn drive lateral circulation. A Hansen-Rattray-like scaling shows good predictive skill for variations in lateral flow. Event-integrated sediment transport is from channel to shoals during down-estuary winds but reversed for up-estuary winds. Accounting for wind-waves results in an order-of-magnitude increase in lateral sediment fluxes. The effects of wind-waves and seagrass beds on nearshore (< 2m) sediment dynamics are explored separately using a nearshore model (NearCoM). Without seagrass beds, wind-waves greatly enhance sediment resuspension, providing a large sediment source for lateral sediment transport. Seagrass beds attenuate wind-wave energy and trap sediments, thus reducing net sediment loss from the shallow shoal

Comparison of Radical Scavenging Activity, Cytotoxic Effects and Apoptosis Induction in Human Melanoma Cells by Taiwanese Propolis from Different Sources

Propolis is a sticky substance that is collected from plants by honeybees. We previously demonstrated that propolins A, B, C, D, E and F, isolated from Taiwanese propolis (TP), could effectively induce human melanoma cell apoptosis and were strong antioxidant agents. In this study, we evaluated TP for free radical scavenging activity by DPPH (1,2-diphenyl-2-picrylhydrazyl). The phenolic concentrations were quantified by the Folin–Ciocalteu method. The apoptosis trigger activity in human melanoma cells was evaluated. TP contained a higher level of phenolic compounds and showed strong capability to scavenge free radicals. Additionally, TP1g, TP3, TP4 and TP7 exhibited a cytotoxic effect on human melanoma cells, with an IC(50) of ∼2.3, 2.0, 3.3 and 3.3 μg/ml, respectively. Flow cytometric analysis for DNA fragmentation indicated that TP1g, TP2, TP3 and TP7 could induce apoptosis in human melanoma cells and there is a marked loss of cells from the G2/M phase of the cell cycle. To address the mechanism of the apoptosis effect of TP, we evaluated its effects on induction of apoptosis-related proteins in human melanoma cells. The levels of procaspase-3 and PARP [poly(ADP-ribose) polymerase] were markedly decreased. Furthermore, propolins A, B, C, D, E and F in TP were determined using HPLC. The results indicate that TP is a rich source of these compounds. The findings suggest that TP induces apoptosis in human melanoma cells due to its high level of propolins

Estuarine exchange flow quantified with isohaline coordinates : contrasting long and short estuaries

Author Posting. © American Meteorological Society, 2012. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 42 (2012): 748–763, doi:10.1175/JPO-D-11-086.1.Isohaline coordinate analysis is used to compare the exchange flow in two contrasting estuaries, the long (with respect to tidal excursion) Hudson River and the short Merrimack River, using validated numerical models. The isohaline analysis averages fluxes in salinity space rather than in physical space, yielding the isohaline exchange flow that incorporates both subtidal and tidal fluxes and precisely satisfies the Knudsen relation. The isohaline analysis can be consistently applied to both subtidally and tidally dominated estuaries. In the Hudson, the isohaline exchange flow is similar to results from the Eulerian analysis, and the conventional estuarine theory can be used to quantify the salt transport based on scaling with the baroclinic pressure gradient. In the Merrimack, the isohaline exchange flow is much larger than the Eulerian quantity, indicating the dominance of tidal salt flux. The exchange flow does not scale with the baroclinic pressure gradient but rather with tidal volume flux. This tidal exchange is driven by tidal pumping due to the jet–sink flow at the mouth constriction, leading to a linear dependence of exchange flow on tidal volume flux. Finally, a tidal conversion parameter Qin/Qprism, measuring the fraction of tidal inflow Qprism that is converted into net exchange Qin, is proposed to characterize the exchange processes among different systems. It is found that the length scale ratio between tidal excursion and salinity intrusion provides a characteristic to distinguish estuarine regimes.SNC is supported by a WHOI postdoctoral scholarship, a NSF Grant OCE-0926427, and a Taiwan National Science Council Grant NSC 100- 2199-M-002-028.WRGis supported byNSFGrantOCE- 0926427. JAL is supported by NSF Grant OCE-0452054.2012-11-0

A SEEMINGLY UNRELETED REGRESSION ANALYSIS ON THE TRADING BEHAVIOR OF MUTUAL FUND INVESTORS

This paper provides a comprehensive investigation on the causality relationship between fund performance and trading flows. We analyze if investors behave asymmetrically in fund purchasing and selling by seemingly unrelated regression which comprises several individual relationships that are linked by the fact that their disturbances or the error terms are correlated. The empirical result shows a significantly negative relationship between fund performance and purchase flows for domestic funds. The magnitude of domestic funds redemption negatively affects current return, but not for international funds. As previousfund return positively affects current net flows,the further lagged performances have no significant impact on the trading flows, revealing that fund investors are sensitive only to short-term past performance. Most importantly, while negative fund performance leads to the increases in redemption, positive performance contrarily leads to the decreases in purchase. The evidences strongly indicate an asymmetry behavior of fund investors in the return-purchase causality relations

THE VARIATION OF DOMINANT ELBOW RANGE OF MOTION AMONG DIFFERENT MATURE STAGE FOR BASEBALL PITCHERS

The purpose of this study was to examine the variation of elbow range of motion (ROM) in the dominant arm between different maturity levels in baseball pitchers. Sixty-two pitchers, including 17 early-puberty players, 22 later-puberty players, and 23 adult players, participated in this study. A goniometer was used to assess elbow ROM in the dominant arms, including elbow flexion, hyper-extension, supination, pronation and valgus angles. The results showed that smaller ROM was found in elbow flexion, supination, and pronation, and larger ROM in elbow valgue, in pithers of later puberty level (

Efficient Detection of Preparing Quantum Remote States Using Coherence Quantum Benefits

A sender can prepare a quantum state for a remote receiver using preshared entangled pairs, only the sender's single-qubit measurement, and the receiver's simple correction informed by the sender. It provides resource-efficient advantages over quantum teleportation for quantum information. Here, we propose the most efficient approach to detect the remote state preparation (RSP) based on the quantum benefits powered by quantum coherence's static resources of the shared pairs and the dynamic resources both the RSP participants input. It requires only the receiver's minimum of one additional coherence creation operation to verify RSP. Experimentally, we implement the introduced RSP assessment using different photon pair states generated from a high-quality polarization Sagnac interferometer, confirming the necessary and sufficient role played by the static and dynamic quantum coherence resources and demonstrating efficient RSP verification. Our results provide a route to efficiently assess RSP in practical scenarios such as quantum information in quantum networks

The potential application of ultra-nanocrystalline diamond films for heavy ion irradiation detection

[[abstract]]The potential of utilizing the ultra-nanocrystalline (UNCD) films for detecting the Au-ion irradiation was investigated. When the fluence for Au-ion irradiation is lower than the critical value (fc = 5.0 × 1012 ions/cm2) the turn-on field for electron field emission (EFE) process of the UNCD films decreased systematically with the increase in fluence that is correlated with the increase in sp2-bonded phase (π*-band in EELS) due to the Au-ion irradiation. The EFE properties changed irregularly, when the fluence for Au-ion irradiation exceeds this critical value. The transmission electron microscopic microstructural examinations, in conjunction with EELS spectroscopic studies, reveal that the structural change preferentially occurred in the diamond-to-Si interface for the samples experienced over critical fluence of Au-ion irradiation, viz. the crystalline SiC phase was induced in the interfacial region and the thickness of the interface decreased. These observations implied that the UNCD films could be used as irradiation detectors when the fluence for Au-ion irradiation does not exceed such a critical value.[[incitationindex]]SCI[[booktype]]電子

Modeling of Turbulent Swirling Flows

Aircraft engine combustors generally involve turbulent swirling flows in order to enhance fuel-air mixing and flame stabilization. It has long been recognized that eddy viscosity turbulence models are unable to appropriately model swirling flows. Therefore, it has been suggested that, for the modeling of these flows, a second order closure scheme should be considered because of its ability in the modeling of rotational and curvature effects. However, this scheme will require solution of many complicated second moment transport equations (six Reynolds stresses plus other scalar fluxes and variances), which is a difficult task for any CFD implementations. Also, this scheme will require a large amount of computer resources for a general combustor swirling flow. This report is devoted to the development of a cubic Reynolds stress-strain model for turbulent swirling flows, and was inspired by the work of Launder's group at UMIST. Using this type of model, one only needs to solve two turbulence equations, one for the turbulent kinetic energy k and the other for the dissipation rate epsilon. The cubic model developed in this report is based on a general Reynolds stress-strain relationship. Two flows have been chosen for model evaluation. One is a fully developed rotating pipe flow, and the other is a more complex flow with swirl and recirculation