3,205 research outputs found
Atmospheric and offshore forcing of temperature variability at the shelf break
Author Posting. © The Oceanography Society, 2018. This article is posted here by permission of The Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 31, no. 1 (2018): 72–79, doi:10.5670/oceanog.2018.112.Knowledge of heat balance and associated temperature variability in the Northwest Atlantic coastal ocean is important for understanding impacts of climate change such as how ocean warming will affect the management of fisheries. Heat balances are particularly complicated near the edge of the continental shelf, where the cross-shelf temperature gradients within the shelf-break front complicate the competing influences of air-sea flux anomalies versus ocean advection. We review the atmospheric and oceanic processes associated with heat balance over the Northwest Atlantic continental shelf and slope, with an emphasis on the scale-dependent nature of the heat balance. We then use data from the Ocean Observatories Initiative (OOI) Pioneer Array to demonstrate heat balance scale dependence at the southern New England shelf break, and the capability of the array to capture multiscale ocean processes. Comparison of the cumulative effects of air-sea heat fluxes measured at the OOI Pioneer Array from May 2015 to April 2016 with the actual temperature change shows the importance of advective processes in overall heat balance near the shelf break.KC was partially supported by the National Science
Foundation under grant OCE-1435602 and OCE-
1634094. GG was supported by the National Science
Foundation under grant OCE-1657853. AP was supported
by the National Science Foundation through
the Cooperative Agreement (subaward) SA9-10
from the Consortium for Ocean Leadership to the
Woods Hole Oceanographic Institution
Editorial for IEEE access special section on theoretical foundations for big data applications : challenges and opportunities
Big data is one of the hottest research topics in science and technology communities, and it possesses a great application potential in every sector for our society, such as climate, economy, health, social science, and so on. Big data usually includes data sets with sizes beyond the ability of commonly used software tools to capture, curate, and manage. We can conclude that big data is still in its infancy stage, and we will face many unprecedented problems and challenges along the way of this unfolding chapter of human history
Modeling the IPv6 Internet AS-level Topology
To measure the IPv6 internet AS-level topology, a network topology discovery
system, called Dolphin, was developed. By comparing the measurement result of
Dolphin with that of CAIDA's Scamper, it was found that the IPv6 Internet at AS
level, similar to other complex networks, is also scale-free but the exponent
of its degree distribution is 1.2, which is much smaller than that of the IPv4
Internet and most other scale-free networks. In order to explain this feature
of IPv6 Internet we argue that the degree exponent is a measure of uniformity
of the degree distribution. Then, for the purpose on modeling the networks, we
propose a new model based on the two major factors affecting the exponent of
the EBA model. It breaks the lower bound of degree exponent which is 2 for most
models. To verify the validity of this model, both theoretical and experimental
analyses have been carried out. Finally, we demonstrate how this model can be
successfully used to reproduce the topology of the IPv6 Internet.Comment: 15 pages, 5 figure
Influence and Optimization of Packet Loss on the Internet-Based Geographically Distributed Test Platform for Fuel Cell Electric Vehicle Powertrain Systems
In view of recent developments in fuel cell electric vehicle powertrain systems, Internet-based geographically distributed test platforms for fuel cell electric vehicle powertrain systems become a development and validation trend. Due to the involvement of remote connection and the Internet, simulation with connected models can suffer great uncertainty because of packet loss. Such a test platform, including packet loss characteristics, was built using MATLAB/Simulink for use in this paper. The simulation analysis results show that packet loss affects the stability of the whole test system. The impact on vehicle speed is mainly concentrated in the later stage of simulation. Aiming at reducing the effect of packet loss caused by Internet, a robust model predictive compensator was designed. Under this compensator, the stability of the system is greatly improved compared to the system without a compensator
Correlation of Gleason Scores with Diffusion-Weighted Imaging Findings of Prostate Cancer
The purpose of our study was to compare the apparent diffusion coefficient (ADC) derived from diffusion-weighted imaging (DWI) of prostate cancer (PCa) patients with three classes of pathological Gleason scores (GS). Patients whose GS met these criteria (GS 3 + 3, GS 3 + 4, and GS 4 + 3) were included in this study. The DWI was performed using b values of 0, 50, and 400 s/mm2 in 44 patients using an endorectal coil on a 1.5T MRI scanner. The apparent diffusion coefficient (ADC) values were calculated from the DWI data of patients with three different Gleason scores. In patients with a high-grade Gleason score (4 + 3), the ADC values were lower in the peripheral gland tissue, pathologically determined as tumor compared to low grade (3 + 3 and 3 + 4). The mean and standard deviation of the ADC values for patients with GS 3 + 3, GS 3 + 4, and GS 4 + 3 were 1.135 ± 0.119, 0.976 ± 0.103 and 0.831 ± 0.087 mm2/sec. The ADC values were statistically significant (P < 0.05) between the three different scores with a trend of decreasing ADC values with increasing Gleason scores by one-way ANOVA method. This study shows that the DWI-derived ADC values may help differentiate aggressive from low-grade PCa
Optimizing and controlling functions of complex networks by manipulating rich-club connections
Traditionally, there is no evidence suggesting that there are strong ties
between the rich-club property and the function of complex networks. In this
study, we find that whether a very small portion of rich nodes connected to
each other or not can strongly affect the frequency of occurrence of basic
building blocks (motif) within networks, and therefore the function, of a
heterogeneous network. Conversely whether a homogeneous network has a rich-club
property or not generally has no significant effect on its structure and
function. These findings open the possibility to optimize and control the
function of complex networks by manipulating rich-club connections.
Furthermore, based on the subgraph ratio profile, we develop a more rigorous
approach to judge whether a network has a rich-club or not. The new method does
not calculate how many links there are among rich nodes but depends on how the
links among rich nodes can affect the overall structure as well as function of
a given network. These results can also help us to understand the evolution of
dynamical networks and design new models for characterizing real-world
networks.Comment: 6 pages, 3 figure
Unified force law for granular impact cratering
Experiments on the low-speed impact of solid objects into granular media have
been used both to mimic geophysical events and to probe the unusual nature of
the granular state of matter. Observations have been interpreted in terms of
conflicting stopping forces: product of powers of projectile depth and speed;
linear in speed; constant, proportional to the initial impact speed; and
proportional to depth. This is reminiscent of high-speed ballistics impact in
the 19th and 20th centuries, when a plethora of empirical rules were proposed.
To make progress, we developed a means to measure projectile dynamics with 100
nm and 20 us precision. For a 1-inch diameter steel sphere dropped from a wide
range of heights into non-cohesive glass beads, we reproduce prior observations
either as reasonable approximations or as limiting behaviours. Furthermore, we
demonstrate that the interaction between projectile and medium can be
decomposed into the sum of velocity-dependent inertial drag plus
depth-dependent friction. Thus we achieve a unified description of low-speed
impact phenomena and show that the complex response of granular materials to
impact, while fundamentally different from that of liquids and solids, can be
simply understood
High-coverage genome of the Tyrolean Iceman reveals unusually high Anatolian farmer ancestry
The Tyrolean Iceman is known as one of the oldest human glacier mummies, directly dated to 3350-3120 calibrated BCE. A previously published low-coverage genome provided novel insights into European prehistory, despite high present-day DNA contamination. Here, we generate a high-coverage genome with low contamination (15.3×) to gain further insights into the genetic history and phenotype of this individual. Contrary to previous studies, we found no detectable Steppe-related ancestry in the Iceman. Instead, he retained the highest Anatolian-farmer-related ancestry among contemporaneous European populations, indicating a rather isolated Alpine population with limited gene flow from hunter-gatherer-ancestry-related populations. Phenotypic analysis revealed that the Iceman likely had darker skin than present-day Europeans and carried risk alleles associated with male-pattern baldness, type 2 diabetes, and obesity-related metabolic syndrome. These results corroborate phenotypic observations of the preserved mummified body, such as high pigmentation of his skin and the absence of hair on his head
Drinfeld twist and symmetric Bethe vectors of the open XYZ chain with non-diagonal boundary terms
With the help of the Drinfeld twist or factorizing F-matrix for the
eight-vertex solid-on-solid (SOS) model, we find that in the F-basis provided
by the twist the two sets of pseudo-particle creation operators simultaneously
take completely symmetric and polarization free form. This allows us to obtain
the explicit and completely symmetric expressions of the two sets of Bethe
states of the model.Comment: Latex file, 25 page
Attack Resilience of the Evolving Scientific Collaboration Network
Stationary complex networks have been extensively studied in the last ten years. However, many natural systems are known to be continuously evolving at the local (“microscopic”) level. Understanding the response to targeted attacks of an evolving network may shed light on both how to design robust systems and finding effective attack strategies. In this paper we study empirically the response to targeted attacks of the scientific collaboration networks. First we show that scientific collaboration network is a complex system which evolves intensively at the local level – fewer than 20% of scientific collaborations last more than one year. Then, we investigate the impact of the sudden death of eminent scientists on the evolution of the collaboration networks of their former collaborators. We observe in particular that the sudden death, which is equivalent to the removal of the center of the egocentric network of the eminent scientist, does not affect the topological evolution of the residual network. Nonetheless, removal of the eminent hub node is exactly the strategy one would adopt for an effective targeted attack on a stationary network. Hence, we use this evolving collaboration network as an experimental model for attack on an evolving complex network. We find that such attacks are ineffectual, and infer that the scientific collaboration network is the trace of knowledge propagation on a larger underlying social network. The redundancy of the underlying structure in fact acts as a protection mechanism against such network attacks
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