A mechanism for the latitudinal dependence of peak-spectrum sea surface height variability

Author Posting. © American Geophysical Union, 2014. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 119 (2014): 1431–1444, doi:10.1002/2013JC009642.Previous studies have shown that the power spectrum of satellite-observed sea surface height (SSH) variability peaks at a certain frequency (or a wave number) band at a given latitude. Lin et al. (2008) attributed this latitudinal dependence to the critical frequency of the first baroclinic mode Rossby waves in the tropical and subtropical oceans. Their study was based on the linear Rossby wave theory and focused on SSH variability in the tropical and subtropical oceans since the altimetry data do not adequately resolve lengths of baroclinic Rossby waves at and near the critical frequency in high latitudes. In this study, we expand their analysis to high-latitude oceanic basins and to include nonlinear eddy effects, by using a linear wave model and a high-resolution model output from the OGCM for the Earth Simulator (OFES). It is found that the linear wave mechanism by and large remains valid in the tropical and subtropical oceans. In higher latitudes as well as in some regions in the western tropical and subtropical oceans, other mechanisms, like nonlinear eddy, play more important role in determining the SSH variability.This work was supported by the China’s National Basic Research Priorities Programmer (2013CB956202), Strategic Priority Research Program of the Chinese Academy of Sciences (XDA11010103), the Natural Science Foundation of China (41222037 and 41221063), the project of Global Change and Air-Sea interaction (GASI-03-01-01–02), the Ministry of Education’s 111 Project (B07036), the National Natural Science Foundation of Shandong (JQ201111), and the National Special Research Fund for Non-Profit Marine Sector (201205018). J. Y. is supported by US NSF (OCE 0927017 and OCE 1028739).2014-08-2

Low-Quality Training Data Only? A Robust Framework for Detecting Encrypted Malicious Network Traffic

Machine learning (ML) is promising in accurately detecting malicious flows in encrypted network traffic; however, it is challenging to collect a training dataset that contains a sufficient amount of encrypted malicious data with correct labels. When ML models are trained with low-quality training data, they suffer degraded performance. In this paper, we aim at addressing a real-world low-quality training dataset problem, namely, detecting encrypted malicious traffic generated by continuously evolving malware. We develop RAPIER that fully utilizes different distributions of normal and malicious traffic data in the feature space, where normal data is tightly distributed in a certain area and the malicious data is scattered over the entire feature space to augment training data for model training. RAPIER includes two pre-processing modules to convert traffic into feature vectors and correct label noises. We evaluate our system on two public datasets and one combined dataset. With 1000 samples and 45% noises from each dataset, our system achieves the F1 scores of 0.770, 0.776, and 0.855, respectively, achieving average improvements of 352.6%, 284.3%, and 214.9% over the existing methods, respectively. Furthermore, We evaluate RAPIER with a real-world dataset obtained from a security enterprise. RAPIER effectively achieves encrypted malicious traffic detection with the best F1 score of 0.773 and improves the F1 score of existing methods by an average of 272.5%

Naringenin prevents TGF-β1 secretion from breast cancer and suppresses pulmonary metastasis by inhibiting PKC activation

Presenting the incidence of pulmonary metastasis (mice with metastasis/total mice). Tumor-bearing mice treated with naringenin or 1D11 were imaged on day 24 using bags to avoid the bioluminescence from primary tumor. The mice with pulmonary metastases were numbered based on the bioluminescence signal. (TIF 26 kb

Transient Hemodynamic Changes upon Changing a BCPA into a TCPC in Staged Fontan Operation: A Computational Model Study

The clinical benefits of the Fontan operation in treating single-ventricle defects have been well documented. However, perioperative mortality or morbidity remains a critical problem. The purpose of the present study was to identify the cardiovascular factors that dominate the transient hemodynamic changes upon the change of a bidirectional cavopulmonary (Glenn) anastomosis (BCPA) into a total cavopulmonary connection (TCPC). For this purpose, two computational models were constructed to represent, respectively, a single-ventricle circulation with a BCPA and that with a TCPC. A series of model-based simulations were carried out to quantify the perioperative hemodynamic changes under various cardiovascular conditions. Obtained results indicated that the presence of a low pulmonary vascular resistance and/or a low lower-body vascular resistance is beneficial to the increase in transpulmonary flow upon the BCPA to TCPC change. Moreover, it was found that ventricular diastolic dysfunction and mitral valve regurgitation, despite being well-known risk factors for poor postoperative outcomes, do not cause a considerable perioperative reduction in transpulmonary flow. The findings may help physicians to assess the perioperative risk of the TCPC surgery based on preoperative measurement of cardiovascular function

FCOS-LSC: A novel model for green fruit detection in a complex orchard environment

To better address the difficulties in designing green fruit recognition techniques in machine vision systems, we propose an optimized FCOS (full convolutional one-stage object detection) algorithm based on LSC attention blocks (FCOS-LSC) that are performed on level scales, spaces and channels of feature map. The method achieves efficient recognition and localization of green fruit images affected by overlapping occlusions, lighting conditions and capture angles. Specifically, the improved feature extraction network ResNet50 with added deformable convolution is used to fully extract green fruit feature information. The feature pyramid network (FPN) is employed to fully fuse low-level detail information and high-level semantic information in a cross-connected and top-down connected way. Next, the attention mechanisms are added to each of the three dimensions of scale, space (including the height and width of the feature map) and channel of the generated multi-scale feature map to improve the feature perception capability of the network. Finally, the classification and regression sub-networks of the model are applied to predict the fruit category and bounding box. In the classification branch, a new positive and negative sample selection strategy is applied to better distinguish supervised signals by designing weights in the loss function to achieve more accurate fruit detection. The proposed FCOS-LSC model has 38.65M parameters (Params), 38.72G floating point operations (FLOPs), and mean average precision (mAP) of 63.0% and 75.2% for detecting green apples and green persimmons, respectively. In summary, FCOS-LSC outperforms the state-of-the-art models in terms of precision and complexity to meet the accurate and efficient requirements of green fruit recognition by intelligent agricultural equipment. Correspondingly, FCOS-LSC can be used to improve the robustness and generalization of the green fruit detection models

High sensitivity micro-fiber Mach-Zehnder interferometric temperature sensors with a high index ring layer

The influence of the high index ring layer (HIRL) in a tapered fiber Mach-Zehnder interferometer (MZI) on the interference observed, and thus on its potential applications in temperature sensing, has been investigated. The MZI was comprised of a tapered Ring Core Fiber (RCF), spliced between two single mode fibers (SMF). Since part of core mode from the SMF was converted into cladding modes in the RCF, due to the mismatch in the cores between the RCF and SMF, the residual power enters and then propagates along the center of the RCF (silica). The difference in phase between the radiation travelling along these different paths is separated by the HIRL to generate an interference effect. Compared with fiber interferometers based on core and cladding mode interference, the thin fiber HIRL is capable of separating the high order cladding modes and the silica core mode, under grazing incident conditions. Therefore, the optical path difference (OPD) and the sensitivity are both substantially improved over what is seen in conventional devices, showing their potential for interferometric temperature sensor applications. The optimum temperature sensitivity obtained was 186.6 pm/°C, which is ∼ 11.7 times higher than has been reported previously

Evolution of anthropogenic air pollutant emissions in Guangdong Province, China, from 2006 to 2015

Guangdong Province (GD), one of the most prosperous and populous regions in China, still experiences haze events and growing ozone pollution in spite of the substantial air-quality improvement in recent years. Integrated control of fine particulate matter (PM2.5) and ozone in GD calls for a systematic review of historical emissions. In this study, emission trends, spatial variations, source-contribution variations, and reduction potentials of sulfur dioxide (SO2), nitrogen oxides (NO), PM2.5, inhalable particles (PM10), carbon monoxide (CO), ammonia (NH3), and volatile organic compounds (VOCs) in GD from 2006 to 2015 were first examined using a dynamic methodology, taking into account economic development, technology penetration, and emission controls. The relative change rates of anthropogenic emissions in GD during 2006-2015 are -48% for SO2, -0.5% for NO, -16% for PM2.5, -22% for PM10, 13% for CO, 3% for NH3, and 13% for VOCs. The declines of SO2, NO, PM2.5, and PM10 emissions in the whole province mainly resulted from the stringent emission control in the Pearl River delta (PRD) region, where most previous control measures were focused, especially on power plants (SO2 and NO), industrial combustion (SO2, PM2.5, PM10), on-road mobile sources (NO), and dust sources (PM2.5 and PM10). Emissions from other areas (non-PRD, NPRD), nevertheless, remain relatively stable due to the lax control measures and rapidly growing energy consumption. In addition, emission leaks of SO2 and NO from industries are observed from PRD to NPRD in 2010 and 2011. As a result, emissions in NPRD are increasingly important in GD, particularly those from industrial combustion. The contribution of NPRD to the total SO2 emissions in GD, for example, increased from 27% in 2006 to 48% in 2015. On-road mobile sources and solvent use are the two key sources that should receive more effective control measures in GD. Current control-driven emission reductions from on-road mobile sources are neutralized by the substantial growth of the vehicle population, while VOC emissions in GD steadily increase due to the growth of solvent use and the absence of effective control measures. Besides, future work could focus on power plants and industrial combustion in GD and industrial process sources in NPRD, which still have large emission reduction potentials. The historical emission inventory developed in this study not only helps to understand the emission evolution in GD, but also provides robust data to quantify the impact of emission and meteorology variations on air quality and unveil the primary cause of significant air-quality change in GD in the recent decade

Experimental study on the vertical deformation of sand caused by cyclic withdrawal and recharging of groundwater

Fast urban growth and an ever-increasing frequency of extreme weather-related events demand a better understanding of land subsidence and the potential measures to control it. This paper presents an experimental investigation on the deformation behavior of sand undergoing cyclic withdrawal and recharging of groundwater. A sand-box model with dimensions 1000 mm × 600 mm × 892 mm was used to investigate soil deformation following lowering and rising of the water table. The sand used was Pingtan sand (Fujian, China) a quartzitic formation composed of elongated to slightly spherical grains. Three sand samples with different initial densities, i.e. loose, medium dense and dense, were tested on repeated cycles. The vertical deformation of the sand was measured and the corresponding strain and effective stress were calculated. The observations show that initially the sand behaves as an elastic material with the subsidence caused by water withdrawal being recovered as the soil rebounds during recharging. With further withdrawal–recharging cycles, subsidence becomes larger as plastic deformations as well as time-dependent deformation occur in the soil. The distinct patterns of deformation were identified to be dependent on both the initial density and the number of withdrawal–recharging cycle the sand has been subjected to. The different behavior of the medium dense sample compared to the loose and dense samples, in particular for the first two cycles, indicates that the soil response cannot be explained in respect of the initial void ratio alone and further microstructure considerations were discussed. It is suggested that the orientation of the grains resulting from the sample preparation technique and the consequent induced anisotropy can be used to explain the results herein presented. Finally this paper provides the rationale for a micromechanical interpretation of soil deformation when subjected to changes in stress due to rising or lowering of the water table, which will help in establishing measures to control land subsidence, in particular to assess the efficiency of water recharging following subsidence by withdrawal

An asymmetric upwind flow, Yellow Sea Warm Current : 1. New observations in the western Yellow Sea

Author Posting. © American Geophysical Union, 2011. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 116 (2011): C04026, doi:10.1029/2010JC006513.The winter water mass along the Yellow Sea Trough (YST), especially on the western side of the trough, is considerably warmer and saltier than the ambient shelf water mass. This observed tongue-shape hydrographic feature implies the existence of a winter along-trough and onshore current, often referred to as the Yellow Sea Warm Current (YSWC). However, the YSWC has not been confirmed by direct current measurements and therefore skepticism remains regarding its existence. Some studies suggest that the presence of the warm water could be due to frontal instability, eddies, or synoptic scale wind bursts. It is noted that in situ observations used in most previous studies were from the central and eastern sides of the YST even though it is known that the warm water core is more pronounced along the western side. Data from the western side have been scarce. Here we present a set of newly available Chinese observations, including some from a coordinated effort involving three Chinese vessels in the western YST during the 2006–2007 winter. The data show unambiguously the existence of the warm current on the western side of YST. Both the current and hydrography observations indicate a dominant barotropic structure of YSWC. The westward deviation of YSWC axis is particularly obvious to the south of 35°N and is clearly associated with an onshore movement of warm water. To the north of 35°N, the YSWC flows along the bathymetry with slightly downslope movement. We conclude that the barotropic current is mainly responsible for the warm water intrusion, while the Ekman and baroclinic currents play an important but secondary role. These observations help fill an observational gap and establish a more complete view of the YSWC.The authors have been supported by China’s National Basic Research Priorities Programmer (2007CB411804 and 2005CB422303), the Ministry of Education’s 111 Project (B07036), the Program for New Century Excellent Talents in University (NECT‐07‐0781), and the China National Science Fundation (40976004, 40921004. and 40930844). J.Y. is supported by the U.S. National Science Foundation and the Woods Hole Oceanographic Institution’s Coastal Ocean Institute