bluuebunny/crossref_metadata_2025 huggingface dataset:
A microwave field-driven transistor-like skyrmionic device with the microwave current-assisted skyrmion creation
Authors: Xia Jing , Huang Yangqi , Zhang Xichao , Kang Wang , Zheng Chentian , Liu Xiaoxi , Zhao Weisheng , Zhou Yan
Published: October 2017

Magnetic skyrmion is a topologically protected domain-wall structure at nanoscale, which could serve as a basic building block for advanced spintronic devices. Here, we propose a microwave field-driven skyrmionic device with the transistor-like function, where the motion of a skyrmion in a voltage-gated ferromagnetic nanotrack is studied by micromagnetic simulations. It is demonstrated that the microwave field can drive the motion of a skyrmion by exciting the propagating spin waves, and the skyrmion motion can be governed by a gate voltage. We also investigate the microwave current-assisted creation of a skyrmion to facilitate the operation of the transistor-like skyrmionic device on the source terminal. It is found that the microwave current with an appropriate frequency can reduce the threshold current density required for the creation of a skyrmion from the ferromagnetic background. The proposed transistor-like skyrmionic device operated with the microwave field and current could be useful for building future skyrmion-based circuits.
Linear and nonlinear frequency- and time-domain spectroscopy with multiple frequency combs
Authors: Bennett Kochise , Rouxel Jeremy R. , Mukamel Shaul
Published: October 2017

Two techniques that employ equally spaced trains of optical pulses to map an optical high frequency into a low frequency modulation of the signal that can be detected in real time are compared. The development of phase-stable optical frequency combs has opened up new avenues to metrology and spectroscopy. The ability to generate a series of frequency spikes with precisely controlled separation permits a fast, highly accurate sampling of the material response. Recently, pairs of frequency combs with slightly different repetition rates have been utilized to down-convert material susceptibilities from the optical to microwave regime where they can be recorded in real time. We show how this one-dimensional dual comb technique can be extended to multiple dimensions by using several combs. We demonstrate how nonlinear susceptibilities can be quickly acquired using this technique. In a second class of techniques, sequences of ultrafast mode locked laser pulses are used to recover pathways of interactions contributing to nonlinear susceptibilities by using a photo-acoustic modulation varying along the sequences. We show that these techniques can be viewed as a time-domain analog of the multiple frequency comb scheme.
Kinetic energy recovery and interface hysteresis of bouncing droplets after inelastic head-on collision
Authors: Zhang Zhenyu , Zhang Peng
Published: October 2017

Binary collision of unequal-size droplets was investigated numerically by using the front tracking method, with particular emphasis in studying the kinetic energy recovery and the interface hysteresis of bouncing droplets. The numerical results were sufficiently validated against the high-quality experimental data in the literature to verify the quantitative predictivity of the numerical methodology in simulating droplet bouncing. Distinct stages of droplet deformation and viscous dissipation during droplet collision were revealed and explained for their dependence on the Weber number and the size ratio. A linear fitting formula that well correlates the kinetic energy recovery factor of bouncing droplets with various collision parameters was proposed and would be practically useful in modeling inelastic droplet bouncing in Lagrangian spray simulation. As an interesting post-collision characteristic of bouncing droplets, the interface hysteresis was found to favor smaller droplet deformation by decreasing the size ratio or decreasing the Weber number or increasing the Ohnesorge number.
Electronic structure and stability of the SiO2+ dications produced in tomographic atom probe experiments
Authors: Zanuttini D. , Blum I. , Rigutti L. , Vurpillot F. , Douady J. , Jacquet E. , Anglade P.-M. , Gervais B.
Published: October 2017

The molecular electronic states of the SiO2+ dication have been investigated in a joint theoretical and experimental analysis. The use of a tip-shaped sample for tomographic atom probe analysis offers the unique opportunity to produce and to analyze the lifetime of some excited states of this dication. The perturbation brought by the large electric field of the polarized tip along the ion trajectory is analyzed by means of molecular dynamics simulation. For the typical electric fields used in the experiment, the lowest energy triplet states spontaneously dissociate, while the lowest energy singlet states do not. We show that the emission process leads to the formation of some excited singlet state, which dissociates by means of spin-orbit coupling with lower-energy triplet states to produce specific patterns associated with Si+ + O+ and Si2+ + O dissociation channels. These patterns are recorded and observed experimentally in a correlated time-of-flight map.
Analysis of thermocapacitive effects in electric double layers under a size modified mean field theory
Authors: Ju Y. Sungtaek
Published: October 2017

Thermodynamics of the electric double layer has received renewed interest for its potential applications in low-grade waste heat harvesting and reversible heating/cooling in supercapacitors. We apply a size-modified mean field theory to analytically capture the influence on the pseudo-Seebeck coefficient S = ∂φ0/∂T)σ of different factors, including the electrode potential φ0, asymmetry in ion sizes, and ion concentration, under a fixed electrode surface charge σ. The pseudo-Seebeck coefficient is predicted to scale as φ0/T at low electrode potentials, but it reaches limiting values when the electrode potential exceeds crossover values due to the steric effect. The qualitative behavior changes substantially, however, when the temperature dependence of the permittivity is taken into account. The pseudo-Seebeck coefficient S is then predicted to scale linearly with φ0 even at high electrode potentials, significantly over-predicting the experimental values. This suggests a strong influence of phenomena not captured in the mean field theory, such as deviation of local effective permittivity from the bulk value, thermally facilitated adsorption or desorption of ions on electrode surfaces, and weakening of ionic associations with temperature.
Phase separation of triethylamine and water in native and organically modified silica nanopores
Authors: Prado J. Rachel , Vyazovkin Sergey
Published: October 2017

A mixture of triethylamine and water is a lower critical solution temperature system that demixes (separates into individual phases) on heating. Differential scanning calorimetry has been applied to study the process of demixing in native and organically modified silica nanopores whose size varied from 4 to 30 nm. It has been found that in both types of nanopores, the temperature and enthalpy of demixing decrease significantly with decreasing the pore size. Isoconversional kinetic analysis has been utilized to determine the activation energy and pre-exponential factor of the process. It has been demonstrated that the depression of the transition temperature upon nanoconfinement is associated with acceleration of the process due to lowering of the activation energy. Nanoconfinement has also been found to lower the pre-exponential factor of the process that has been linked to a decrease in the molecular mobility.
Symmetry, Hopf bifurcation, and the emergence of cluster solutions in time delayed neural networks
Authors: Wang Zhen , Campbell Sue Ann
Published: October 2017

We consider the networks of N identical oscillators with time delayed, global circulant coupling, modeled by a system of delay differential equations with ZN symmetry. We first study the existence of Hopf bifurcations induced by the coupling time delay and then use symmetric Hopf bifurcation theory to determine how these bifurcations lead to different patterns of symmetric cluster oscillations. We apply our results to a case study: a network of FitzHugh-Nagumo neurons with diffusive coupling. For this model, we derive the asymptotic stability, global asymptotic stability, absolute instability, and stability switches of the equilibrium point in the plane of coupling time delay (τ) and excitability parameter (a). We investigate the patterns of cluster oscillations induced by the time delay and determine the direction and stability of the bifurcating periodic orbits by employing the multiple timescales method and normal form theory. We find that in the region where stability switching occurs, the dynamics of the system can be switched from the equilibrium point to any symmetric cluster oscillation, and back to equilibrium point as the time delay is increased.
A new storage management on stochastic charge-discharge mode
Authors: Zhu Jian-hong , Pan Wen-xia
Published: October 2017

The energy management problem of the battery is always a technical challenge, especially when incomplete charging-discharging alternation happens continuously under the complex state, as the application participating in a real-time schedule of wind farm power. This paper focuses on the energy management of the battery which participates in wind power optimal forecast. First, innovative energy management strategy is designed to avoid non-linear model construction of the battery. In terms of the energy-exchange equivalent prediction method, the energy management scheme can make full use of peripheral parameters tested from charge-discharge interface circuit. Then, the charge-discharge power is obtained from the active demand of wind power forecast error correction, the converter efficiency, and the self-discharge factor. In addition, a diagnosis method of health status based on judgment of coefficient mutation and a life cycle algorithm based on integral statistics of the whole process are studied, respectively. Second, to facilitate the subsequent prediction, the capacity change of the actual storage system is revised in a manner where the static and dynamic parameters consist of actual current-time integration during the charge or discharge process and equivalent parameter correction of the relation between power energy throughput and charge capacity change. The transmission efficiency correction of converter and self-discharge efficiency, the dynamic determination of the battery health state, and life cycle statistics are also considered. Finally, a practical application case is introduced to validate the above strategies. The results verify that both the dynamic forecast of the state of charge and the feasible management of energy storage are achieved.
90 nm gate length enhancement-mode AlGaN/GaN HEMTs with plasma oxidation technology for high-frequency application
Authors: Mi Min-Han , Ma Xiao-Hua , Yang Ling , Bin-Hou  , Zhu Jie-Jie , He Yun-Long , Zhang Meng , Wu Sheng , Hao Yue
Published: October 2017

High-frequency enhancement-mode (E-mode) AlGaN/GaN high-electron-mobility transistors (HEMTs) with plasma oxidation technology (POT) were fabricated through plasma-enhanced chemical vapor deposition. POT enables the formation of a thin oxide layer in the gate region, which decreases the gate leakage by at least two orders of magnitude compared with conventional recessed gate HEMTs. Ultra-low leakage was achieved in the fabricated device, with Ioff = 9.5 × 10−7 mA/mm and a high ON/OFF ratio of over 109. Good suppression of current collapse was obtained after the application of POT in the access region. The enhancement-mode AlGaN/GaN HEMTs with POT showed an outstanding performance, with a Vth of 0.4 V, a maximum drain current of 965 mA/mm, and an fmax of 272 GHz.
Signal distortion in atomic force microscopy photodetector
Authors: Eppell Steven J. , Feinstein Matthew , Li Li , White Brandon , Zypman Fredy R.
Published: October 2017

The frequency-dependent complex impedance of an atomic force microscope photodetector is measured. The inverse problem is solved obtaining the voltage that would have been collected with a hypothetical, perfectly flat-frequency-response photodetector from the experimentally available voltage. This information is used to study the distortion that the true input signal undergoes as it passes through the photodetector on the way to becoming the experimentally measured output signal. It is found that signals with features of interest shorter than 10 μs render noticeable differences between the true and measured raw voltages and forces. Signals with features shorter than 1 μs produce experimentally measured force curves that deviate substantially from the true force curves. A method is proposed for correcting the measured raw voltage signal.
Mantras of wildland fire behaviour modelling: facts or fallacies?
Authors: Cruz Miguel G. , Alexander Martin E. , Sullivan Andrew L.
Published: October 2017

Generalised statements about the state of fire science are often used to provide a simplified context for new work. This paper explores the validity of five frequently repeated statements regarding empirical and physical models for predicting wildland fire behaviour. For empirical models, these include statements that they: (1) work well over the range of their original data; and (2) are not appropriate for and should not be applied to conditions outside the range of the original data. For physical models, common statements include that they: (3) provide insight into the mechanisms that drive wildland fire spread and other aspects of fire behaviour; (4) give a better understanding of how fuel treatments modify fire behaviour; and (5) can be used to derive simplified models to predict fire behaviour operationally. The first statement was judged to be true only under certain conditions, whereas the second was shown not to be necessarily correct if valid data and appropriate modelling forms are used. Statements three through five, although theoretically valid, were considered not to be true given the current state of knowledge regarding fundamental wildland fire processes.
Lack of BACE1 S-palmitoylation reduces amyloid burden and mitigates memory deficits in transgenic mouse models of Alzheimer’s disease
Authors: Andrew Robert J. , Fernandez Celia G. , Stanley Molly , Jiang Hong , Nguyen Phuong , Rice Richard C. , Buggia-Prévot Virginie , De Rossi Pierre , Vetrivel Kulandaivelu S. , Lamb Raza , Argemi Arnau , Allaert Emilie S. , Rathbun Elle M. , Krause Sofia V. , Wagner Steven L. , Parent Angèle T. , Holtzman David M. , Thinakaran Gopal
Published: October 2017

Significance

Alzheimer’s disease (AD) is a devastating neurodegenerative disorder for which no preventative drug or cure is currently available. BACE1 is a key enzyme that initiates the production of β-amyloid peptides (Aβ), which accumulate in AD brain and contribute to cognitive decline. BACE1 undergoes S-palmitoylation, a lipid modification that is known to regulate neuronal protein trafficking. We investigated the in vivo significance of BACE1 S-palmitoylation by generating knock-in mice selectively lacking this modification. The lack of BACE1 S-palmitoylation impaired synaptic activity-induced Aβ production, significantly reduced cerebral amyloid burden in AD mouse models, and mitigated cognitive deficits. Using transgenic mouse models, our results demonstrate that intrinsic posttranslational S-palmitoylation of BACE1 has a significant impact on amyloid pathogenesis and the consequent cognitive decline.
IncV, a FFAT motif-containing
Chlamydia
protein, tethers the endoplasmic reticulum to the pathogen-containing vacuole
Authors: Murray Rebecca , Flora Elizabeth , Bayne Charlie , Derré Isabelle
Published: October 2017

Membrane contact sites (MCS) are zones of contact between the membranes of two organelles. At MCS, specific proteins tether the organelles in close proximity and mediate the nonvesicular trafficking of lipids and ions between the two organelles. The endoplasmic reticulum (ER) integral membrane protein VAP is a common component of MCS involved in both tethering and lipid transfer by binding directly to proteins containing a FFAT [two phenylalanines (FF) in an acidic tract (AT)] motif. In addition to maintaining cell homeostasis, MCS formation recently emerged as a mechanism by which intracellular pathogens hijack cellular resources and establish their replication niche. Here, we investigated the mechanism by which the
Chlamydia-
containing vacuole, termed the inclusion, establishes direct contact with the ER. We show that the
Chlamydia
protein IncV, which is inserted into the inclusion membrane, displays one canonical and one noncanonical FFAT motif that cooperatively mediated the interaction of IncV with VAP. IncV overexpression was sufficient to bring the ER in close proximity of IncV-containing membranes. Although IncV deletion partially decreased VAP association with the inclusion, it did not suppress the formation of ER-inclusion MCS, suggesting the existence of redundant mechanisms in MCS formation. We propose a model in which IncV acts as one of the primary tethers that contribute to the formation of ER-inclusion MCS. Our results highlight a previously unidentified mechanism of bacterial pathogenesis and support the notion that cooperation of two FFAT motifs may be a common feature of VAP-mediated MCS formation.
Chlamydia
–host cell interaction therefore constitutes a unique system to decipher the molecular mechanisms underlying MCS formation.
Numerous interactions act redundantly to assemble a tunable size of P bodies in
Saccharomyces cerevisiae
Authors: Rao Bhalchandra S. , Parker Roy
Published: October 2017

Significance

RNA–protein (RNP) granules contribute to spatiotemporal regulation of gene expression in eukaryotes. RNP granules have also been implicated in the pathology of neurodegenerative diseases. Insights into mechanisms of assembly and disassembly are fundamental to understanding the biology of RNP granules. In this manuscript, we provide evidence to support a model for P-body assembly which suggests that a summation of scaffolding interactions drives P-body assembly and scales the size of P body-related assemblies. Since the multivalent nature of factors and scaffolding interactions is a conserved feature of most RNP granules, our model provides an overarching theme for how other RNP granules in biology could assemble and function in vivo.
Quantitative proteomics identifies STEAP4 as a critical regulator of mitochondrial dysfunction linking inflammation and colon cancer
Authors: Xue Xiang , Bredell Bryce X. , Anderson Erik R. , Martin Angelical , Mays Christopher , Nagao-Kitamoto Hiroko , Huang Sha , Győrffy Balázs , Greenson Joel K. , Hardiman Karin , Spence Jason R. , Kamada Nobuhiko , Shah Yatrik M.
Published: October 2017

Significance

Inflammation is a major risk factor for many cancers and the role of metabolic reprogramming in the inflammatory progression of cancer is not clear. We used a quantitative proteomic approach to identify mitochondrial proteins that are altered early in intestinal inflammation. We show that mitochondrial iron dysregulation is an early event that initiates mitochondrial dysfunction. Through the proteomic analysis, we identified a mitochondrial iron reductase, six-transmembrane epithelial antigen of prostate 4 (STEAP4), as being highly elevated during inflammation. Using intestinal epithelial-specific STEAP4 mice, we show that an increase in STEAP4 is sufficient to alter mitochondrial iron homeostasis. Chronic increase in mitochondrial iron leads to tissue injury and potentiates colon cancer, whereas mitochondrial iron chelation is protective in colitis and colitis-associated colon cancer models.
Reciprocal cross-regulation of VND and SND multigene TF families for wood formation in
Populus trichocarpa
Authors: Lin Ying-Chung Jimmy , Chen Hao , Li Quanzi , Li Wei , Wang Jack P. , Shi Rui , Tunlaya-Anukit Sermsawat , Shuai Peng , Wang Zhifeng , Ma Hongyan , Li Huiyu , Sun Ying-Hsuan , Sederoff Ronald R. , Chiang Vincent L.
Published: October 2017

Significance

Wood is a widely used renewable feedstock for industrial production and energy generation. The secondary cell wall (SCW) is the major component of wood. Two key transcription factor families, Vascular-Related NAC-Domain (VND) and Secondary Wall-Associated NAC Domain (SND), are master gene regulators for SCW biosynthesis. However, plants exhibit stunted growth or abnormal SCW development under excess VND or SND gene expression. In this study, we show that two splice variants, PtrVND6-C1
IR
and PtrSND1-A2
IR
, each from VND and SND families, act as negative regulators. We propose that PtrVND6-C1
IR
and PtrSND1-A2
IR
function together for reciprocal cross-regulation of VND and SND families to maintain homeostasis for xylem differentiation and plant development.
Requirement of the fusogenic micropeptide myomixer for muscle formation in zebrafish
Authors: Shi Jun , Bi Pengpeng , Pei Jimin , Li Hui , Grishin Nick V. , Bassel-Duby Rhonda , Chen Elizabeth H. , Olson Eric N.
Published: October 2017

Significance

The formation of skeletal muscle fibers during embryogenesis and adult injury-induced muscle repair occurs through the fusion of myoblasts. We recently discovered myomixer, a muscle-specific micropeptide required for myoblast fusion in mice. Myomixer and myomaker, another muscle-specific membrane protein, are sufficient to induce fusion of nonmuscle cells. Here, we extend these findings and demonstrate the requirement of myomixer for zebrafish myoblast fusion. We also demonstrate a striking functional conservation of myomixer in zebrafish, elephant shark, and turtle among other species. Comparison of conserved regions of myomixer in these species led to the identification of peptide domains essential for myomixer function. Our findings provide further understanding of the mechanistic basis of myomixer function and muscle cell fusion during development and regeneration.
Lifetime Marijuana and Alcohol use, and Cognitive Dysfunction in People with Human Immunodeficiency virus Infection
Authors: Lorkiewicz Sara A. , Ventura Alicia S. , Heeren Timothy C. , Winter Michael R. , Walley Alexander Y. , Sullivan Meg , Samet Jeffrey H. , Saitz Richard
Published: October 2017

Background

Substance use is common among people with human immunodeficiency virus (HIV) infection. Alcohol, marijuana, and HIV can have negative effects on cognition. Associations between current and lifetime marijuana and alcohol use and cognitive dysfunction in people with HIV infection were examined.

Methods

Some 215 HIV-infected adults with Diagnostic and Statistical Manual of Mental Disorders Fourth Edition (DSM-IV) substance dependence or ever injection drug use were studied. In adjusted cross-sectional regression analyses associations were assessed between current marijuana use, current heavy alcohol use, lifetime marijuana use, lifetime alcohol use, duration of heavy alcohol use (the independent variables), and 3 measures of cognitive dysfunction (dependent variables): both the (i) memory and (ii) attention domains from the Montreal Cognitive Assessment (MoCA) and the (iii) 4-item cognitive function scale (CF4) from the Medical Outcomes Study HIV Health Survey (MOS-HIV). Analyses were adjusted for demographics, primary language, depressive symptoms, anxiety, comorbidities, antiretroviral therapy, hepatitis C virus (ever), duration of HIV infection (years), HIV-viral load (log copies/mL), CD4 cell count, lifetime and recent cocaine use, and recent illicit and prescribed opioid use.

Results

Current marijuana use was significantly and negatively associated with the MOS-HIV CF4 score (adjusted mean difference = −0.40, P = .01). Current marijuana use was not significantly associated with either MoCA score. Lifetime marijuana use and current heavy and lifetime alcohol use and duration of heavy alcohol use were not associated with any measure of cognitive dysfunction.

Conclusion

Current marijuana use was associated with one measure of cognitive dysfunction, but there was not a consistent pattern of association with lifetime marijuana use or alcohol use and measures of cognitive dysfunction. Understanding the mechanism by which marijuana, with and without alcohol, are associated with worse cognition warrants larger, longer studies with more precise and diverse measurements of cognitive function.
Preliminary assessment of sewage contamination in coastal sediments of Kuwait following a major pumping station failure using fecal sterol markers
Authors: Saeed T. , Al-Bloushi A. , Abdullah H. I. , Al-Khabbaz A. , Jamal Z.
Published: October 2017

This preliminary study was undertaken to assess the sewage contamination of Kuwait's coastal areas that received untreated sewage after a major pumping station failure (24 August 2009). About 180,000–200,000 m3 day−1 of untreated sewage was released for many months. Fecal sterols (especially coprostanol), considered to be ideal markers for sewage pollution, were used for the assessment. A total of 28 sediment samples were analyzed for the sterols. Coprostanol, cholesterol and cholestanol levels and their ratios were determined by GC/MS selective ion monitoring. The results showed that coastal areas receiving untreated wastewater were heavily contaminated with sewage. Coprostanol levels ranged from 874–41,228 ng g−1 dry wt. Sterol ratios based assessment resulted in categorization of some of the sites as ‘grossly contaminated,’ while most of the sites were ‘highly contaminated.’ Comparison with previously collected samples clearly showed the trend of increasing contamination.
Phytoplankton growth on organic nutrients from trash fish
Authors: Gao Yongli , Yin Kedong , He Lei , Harrison Paul J.
Published: October 2017

Trash fish is common feed for caged fish in marine aquaculture. Most feed is not eaten and enters the water surrounding fish farms. The organic matter in trash fish is a nutrient source contributing to aquatic eutrophication impacts such as algal blooms and low oxygen. The objective of this study was to examine whether phytoplankton utilized organic matter of trash fish directly. Fifteen microalgae species were cultured in the medium made of open oceanic water with f/2 enrichment (Treatment A, f/2 medium), with only silicate added (Treatment B, for diatom species) and with fish tissue+silicate (Treatment C). Four species grew significantly faster on fish tissue than in f/2 medium, another 4 species had similar growth rates between the two treatments (A and C). Growth rates of Pyramimonas sp. on different amount of fish tissue appeared to increase initially with increasing added fish tissue weight, reached a maximum at an intermediate amount of fish tissue additions. Time course of batch culture of Chaetoceros curvisetus showed that the species was capable of utilizing organic nitrogen released from fish tissue and grew well. Dissolved organic nitrogen (DON) was lower in the batch culture with algae and fish tissue than that with fish tissue but without algae in the medium, which indicated a direct utilization of DON during algal growth. These results indicated that fish tissue could be a direct nutrient source to support phytoplankton growth and coastal management needs to pay attention to organic contamination from trash fish.
Factors controlling nitrous oxide in the inner Pearl River Estuary, Northern South China Sea
Authors: Wang You-Shao , Wu Mei-Lin , Xu Ji-Rong , Sun Cui-Ci , Dong Jun-De , Wang Yu-Tu , Sun Fu-Lin
Published: October 2017

Chemometrics coupling geographic information system (GIS) was applied to investigate the spatial distribution patterns of nitrous oxide in the water column, its relation with environmental factors and to identify spatial human impacts on local scales. N2O concentrations in both the surface and bottom waters of the inner Pearl River Estuary had obvious variability along the Pearl River. The spatial variation in distribution of N2O concentration in the inner Pearl River Estuary was influenced by freshwater discharge along salinity gradients, which highlights the effects of human impacts on N2O emission rates. Principal component analysis recognized human impacts and their affected areas. The primary anthropogenic source in the area was domestic sewage. Cluster analysis further confirmed the results of principal component analysis. Moreover, GIS-based spatial analysis facilitated chemometrics.
Spatial-temporal variability of total and size-fractionated phytoplankton biomass in the Yangtze River Estuary and adjacent East China Sea coastal waters, China
Authors: Zhou Weihua , Yin Kedong , Long Aimin , Huang Hui , Huang Liangmin , Zhu Dedi
Published: October 2017

The spatial and seasonal dynamics of total and size-fractionated phytoplankton biomass (chlorophyll- a) as well as physical and chemical factors in the Yangtze River Estuary and adjacent East China Sea coastal waters were investigated from April 2002 to February 2003. Average surface total and water column integrated chlorophyll a biomass showed a clear seasonal variation in response to the Yangtze River discharge, with the highest in summer (∼4 mg m−3 and >60 mg m−2), intermediate in spring and autumn (∼1 mg m−3 and 26–28 mg m−2), and the lowest in winter (0.5 mg m−3 and <20 mg m−2). Summer maximum chlorophyll a concentrations (>10 mg m−3) occurred at intermediate salinities (∼20–30) region beyond the front zone between 112.5°E and 123°E with sufficient nutrients replenishment for phytoplankton growth. Generally, spatial distribution of size-fractionated phytoplankton showed that phytoplankton biomass was dominated by the large size fraction (>20 μm) in the turbid eutrophic estuarine and near-shore waters, while the small-sized phytoplankton (<5 μm) were dominant in the offshore stations. Phosphate was the main limiting nutrient of phytoplankton biomass in river diluted water and most near-shore stations, while dissolved inorganic nitrogen became the potential limiting nutrient in some offshore stations, except for summer when phosphate limited almost all in the whole investigation region. Controlling the inputs of phosphate loading from the Yangtze River is one of the most effective strategies for reducing the increasing eutrophication and occurrences of harmful algal blooms in Yangtze River Estuary and adjacent East China Sea coastal waters.
Fish community structure in the Bay of Quinte, Lake Ontario: The influence of nutrient levels and invasive species
Authors: Hoyle J. A. , Bowlby J. N. , Brousseau C. M. , Johnson T. B. , Morrison B. J. , Randall R. G.
Published: October 2017

Intensive, long-term sampling in the Bay of Quinte with multiple gears (i.e. gill nets, bottom trawls, trap nets and boat electrofishing) allowed examination of the fish community and major fish populations in the context of key stressors up to 2009. Excessive nutrient input and hyper-abundant non-native fish species, White Perch and Alewife, shaped the depreciated fish community of the 1970s. After implementation of phosphorus input control measures and simultaneous winter-kills of the hyper-abundant non-native fish in the late 1970s, Walleye recovered and served to restore a predator-prey balance to the fish community by the late 1980s. However, in the absence of a significant recovery of submerged aquatic vegetation (SAV) in littoral areas, off-shore species (e.g. Alewife and White Perch) still tended to dominate; even in littoral areas. Following establishment of Dreissenid Mussels in the mid-1990s, water transparency increased and SAV increased significantly in littoral areas. This pivotal event led to a shift in the fish community that included an overall decline in Walleye, an increase followed by a decrease in Yellow Perch, and dominance by centrarchids (i.e. Bluegill, Pumpkinseed, Black Crappie and Largemouth Bass) in the nearshore. Round Goby invaded in 1999, proliferated and became important in the diet of piscivores by 2003. The current species assemblage, including the piscivores, is diverse and indicative of a healthy fish community.
Assessing ecosystem health impairments using a battery of ecological indicators: Bay of Quinte, Lake Ontario example
Authors: Munawar M. , Fitzpatrick M. , Munawar I. F. , Niblock H. , Kane D.
Published: October 2017

Large freshwater and marine ecosystems suffer from a variety of anthropogenic stressors which include eutrophication, chemical contamination, coastal degradation and overexploitation of fisheries to name only a few. Attempts at remediation are often confounded by the multitude of local, regional, national and international governments and agencies that exercise jurisdiction over smaller parts of these ecosystems. In the North American Great Lakes, there exists a (nearly) 40 year track record for international cooperation in managing anthropogenic stressors that emphasizes sound ecosystem based science. Among these efforts was the designation of 42 severely polluted coastal regions as Areas of Concern (AoCs) which were deemed to have at least 1 of 14 possible Beneficial Use Impairments. The Bay of Quinte, Lake Ontario, is one AoC with 10 listed impairments. We used a “battery of tests” strategy to assess the health of the bay with respect to the impairments of “eutrophication or undesirable algae” and “degradation of phytoplankton and zooplankton communities” in the bay. This strategy integrates structural, functional and chemical parameters into established ecosystem health models. The results of the battery of tests showed continued eutrophication of the bay and not coincidentally, continued degradation of the phytoplankton community. We also found that point sources of phosphorous do not account for all of the (pelagic) primary production observed in the bay and suggest that non-point sources of phosphorous contribute significantly to eutrophication. Our results further suggest that the battery of tests strategy is a sensitive science-based tool for assessing ecosystem health. These tests could also be applied to the evaluation of ecosystem health in other Great Lakes AoCs as well as large lakes and marine environments where cultural eutrophication is a problem.
Litter composition and source contribution for 80 beaches in Greece, Eastern Mediterranean: A nationwide voluntary clean-up campaign
Authors: Kordella S. , Geraga M. , Papatheodorou G. , Fakiris E. , Mitropoulou I. M.
Published: October 2017

Litter that accumulates in the marine environment is recognized as a global environmental problem with numerous adverse effects. Despite Greece having more than 16,000 km of coastline, studies on litter composition and sources on its beaches are scarce and fragmentary. Therefore, this study aimed to quantify beach-stranded litter by type of material (plastic, glass, paper, aluminum, other metals, building materials, rope) on 80 Greek beaches, and to explore the relationships between different litter materials and marine- and land-based sources. Field work and data collection were accomplished with the participation of 10,938 and 15,748 volunteers in 2006 and 2007, respectively, and were integrated in the nationwide campaign of voluntary beach clean-ups: “Clean up the Med.” The participation of thousands of volunteers of different ages and social backgrounds in the data collection process not only led to the realization of a national level survey, but also played a significant role in raising public awareness on marine environmental issues, and in promoting a sense of responsibility in protecting marine resources. Plastic was the most abundant litter material found on the surveyed beaches (43–51%), followed by paper (13–18%) and aluminum (7–12%). Onshore and nearshore recreational activities, such as bathing and recreational boating, appeared to be the most dominant litter sources, as they affect the majority (56) of the surveyed beaches, suggesting that environmental education and awareness could reduce the beach-litter pollution problem. Navigation seemed to be the dominant source of marine-based litter, affecting more than half (46) of the surveyed beaches.
Benthic marine biodiversity patterns across the United Kingdom and Ireland determined from recreational diver observations: A baseline for possible species range shifts induced by climate change
Authors: Bull James C. , Mason Sam , Wood Chris , Price Andrew R. G.
Published: October 2017

Using benthic species abundance records (2003–2009) collected by volunteer divers through ‘Seasearch’, coastal biodiversity patterns around the United Kingdom and Ireland were investigated. The first aim was to assess the utility of volunteer data as a baseline for monitoring environmental change. Separation of the influences of within- and between-surveyor variation from broadscale (year, latitude, longitude) and finer scale (month, depth, local habitat) biogoegraphical factors was achieved using a multilevel mixed effects framework. A high degree of consistency within surveyors was evident and, by modelling between-surveyor variations efficiently, expected trends in species richness and taxonomic distinctness were recovered. Moving from patterns to processes, the second aim was to test the effects of sea surface temperature on prevalence, on a species by species basis. This approach allowed identification of species likely to display range shifts in direct response to future warming trends. Within limitations, volunteer data can provide a valuable contribution to understanding of biodiversity, climate change and aquatic ecosystem health.
Floristic quality assessment for marshes in Alberta's northern prairie and boreal regions
Authors: Wilson Matthew J. , Forrest Andrew S. , Bayley Suzanne E.
Published: October 2017

Floristic quality indices are used to monitor and assess wetland condition by measuring a plant community's tolerance to environmental stress. The aim of our research was to evaluate whether stormwater and reclamation marshes supported wet meadow plant communities that were similar in floristic quality to reference wetlands. Coefficients of conservatism were assigned to a comprehensive list of marsh plant species by nine expert botanists. Various metrics such as the floristic quality index (FQI) were tested for a linear relationship to regional environmental stress gradients in 78 sites in the northern prairies (Aspen Parkland) and 66 sites in the Boreal Plains ecoregions in Alberta, Canada. Sensitivity of floristic quality metrics to the stress gradients was higher when rare species were excluded (species with <5% site-level cover). An adjusted FQI that eliminated bias towards sites with higher species richness yielded the strongest relationship to the stress gradient in both ecoregions (r2 = 0.55 in northern prairies; r2 = 0.46 in Boreal Plains). The adjusted FQI also yielded more consistent scores than richness-weighted metrics in a subset of 47 sites where sampling was replicated in dry and wet years (r = 0.75). Including exotic species in floristic quality metrics was not beneficial in the northern prairies where reference sites were located near areas of high urban and agricultural development. This study demonstrates that floristic quality assessments are reasonably good predictors of plant community condition in relation to environmental stress. Results of this study also highlight that existing stormwater ponds and reclamation marshes are not successfully restoring plant community habitat.
Status of Ganges River Dolphin (Platanista gangetica gangetica) in the Ganga River Basin, India: A review
Authors: Behera Sandeep Kumar , Singh Hari , Sagar Viveksheel
Published: October 2017

River Dolphins are among the world's most threatened mammals. The rapid growth of human populations, widespread habitat degradation, pollution, flow regulation and water extraction, fisheries overexploitation and weaknesses of protective legislation have caused severe declines in the range and abundance of Ganges River Dolphins in India. Due to rising conservation concerns, dolphin biologists in the country have conducted a great deal of research over the past few decades on the status and trends of the sub-species in its distribution range. However, empirical studies are still lacking on the ecology of River dolphins, both to inform conservation efforts and to help address broader concerns related to biodiversity conservation and the sustainability of human use of river systems. Existing conservation efforts might be insufficient to stem the ongoing decline of freshwater dolphins in the country. In this article we review the status of Ganges River Dolphins, with a focus on threats the sub-species is facing in its current distribution range, and provide recommendations for its conservation.
Littoral fisheries on Cichlidae (Pisces) from the northwestern part of Lake Tanganyika, East Africa
Authors: Mushagalusa C. D. , Nshombo M. , Lushombo M.
Published: October 2017

This study describes the inshore fishery on the littoral cichlids in Lake Tanganyika, to evaluate the potential impact of fishing gear on the cichlid fishes and their diversity. The fishing activity at the northwestern end of Lake Tanganyika in Uvira was examined from March to July 2010. In total, the catch examined was composed of 3,555 cichlid fish: 47 species and 30 genera identified representing 10 of the 16 tribes of Lake Tanganyika cichlids. Fishermen in Uvira, exploiting littoral cichlids, used three main fishing gears including beach seine, frame gillnet and mosquito net, varying according to the substrates of the littoral habitat at different study sites. They generally captured immature fishes (63%) and small-sized fish due to their small mesh size and unsuitable fishing techniques. The beach seine caught more species on the sandy substrate while the frame gillnets caught more individuals. The cichlid species Aulonocranus dewindti was the most abundant in the catches.
Risk assessment of wetland under aluminium and iron toxicities: A review
Authors: Ayeni O. , Kambizi L. , Laubscher C. , Fatoki O. , Olatunji O.
Published: October 2017

The chemical composition of aquatic habitat, environmental conditions and trend monitoring could reflect changes in species composition over time. Vegetation plays an important role in decontamination and waste treatment water inlet and received by wetlands. They provide carbon substrate for microbes which are important in processing wastewater contaminants. Metabolism in plants, however, requires micronutrients such as Aluminium (Al) and Iron (Fe). Al is toxic to many plants at concentrations greater than 2–3 pap at soil pH < 5.5. Al interferes with cell divisions in root tips and lateral roots, increases cell wall rigidity, maintains proper cellular redox state and various other biochemical, physiological and growth responses. Excess concentration of reducible Fe on acidic soils poses constraint primarily on wetland plants. The authors evaluate aspects of Al and Fe in anoxic biochemical processes, Al and Fe uptake, transport and distribution in wetland ecosystem. The review objective is to focus on wetland monitoring, as it was discovered that wetland ecosystems are at risk of degradation unless properly managed. A poor understanding of the value of wetlands will continue to encourage resource overuse and degradation, thus escalating threats to development through the environmental risk associated with remobilization of metal contaminants and the recycling to the food chain. Protection and restoration of aquatic ecosystems and their services in the face of pressures from land-use change, urbanization, and global warming which affects climate change, rising sea level, coastal erosion and lowland flooding are important.
Retrieving total suspended matter in Lake Taihu from HJ-CCD near-infrared band data
Authors: Li Junsheng , Shen Qian , Zhang Bing , Chen DongMei
Published: October 2017

Among water quality parameters, total suspended matter is important for the evaluation of inland waters. A recently launched satellite sensor, HJ-CCD, by China possesses high temporal resolution, medium spatial resolution, and wide swath, so it is convenient for monitoring this parameter in large inland waters. However, no operational method currently exists for retrieving the total suspended matter concentration of turbid inland waters from HJ-CCD data. Using Lake Taihu in Eastern China as a study area, we obtained and analyzed optical properties of the lake during all seasons, and found that the absorption coefficient of suspended matter, chlorophyll, and colored dissolved organic matter of the near-infrared band may approximate zero. Based on this analysis, we found that a single band method of retrieving concentration using the near-infrared band was suitable using HJ-CCD data. We parameterized the single band method with specific inherent optical properties of Lake Taihu, and validated it using the results retrieved from a HJ-CCD image taken on 14 March 2009, as well as water-surface quasi-synchronous measured data. The concentration retrieved from the image is precise and stable; the single band method uses the established specific optical property database in the study area for input parameters, and does not need support from synchronous data. With this method, HJ-CCD may be applied to retrieve total suspended matter of other highly turbid inland waters.
Mapping the distribution of suspended particulate matter concentrations influenced by storm surge in the Yellow River Estuary using FY-3A MERSI 250-m data
Authors: Zhao W. , Sun L. , Cui T. , Cao W. , Ma Y. , Hao Y.
Published: October 2017

This is a study observing the application of Medium Resolution Spectral Imager 250-m data on-board Fengyun-3A in the analysis of spatio-temporal distributions of suspended particulate matter influenced by storm surge in the Yellow River Estuary. Based on in situ suspended particulate matter concentrations and remote sensing reflectance (Rrs) obtained from the Yellow River Estuary in 2011, a statistical retrieval algorithm was developed for Fengyun-3A Medium Resolution Spectral Imager data with 250-m spatial resolution. The best correlation was obtained for the reflectance ratios Rrs(865)/Rrs(550) and Rrs(650)/Rrs(550). With this simple empirical relationship, the absolute percentage difference (APD) was 29% (linear scale) and the correlation coefficient was 0.97, based on an independent validation data set. Furthermore, the model was proved to be insensitive to the input noise and could be considered stable and reliable. With a lookup-table-based method on atmospheric correction and developed suspended particulate matter retrieval model, these 250-m images were used to map the spatio-temporal distributions under the influence of a storm surge. This research showed that suspended particulate matter distribution and diffusion changes were predominant features during a storm surge in the entire Bohai Sea, especially in the Yellow River Estuary. This study also demonstrated that the moderately high resolution of this 250-m data had great potential in monitoring the transport of ocean colour constituents, particularly in small bodies of water such as bays and estuaries.