2,932 research outputs found
Spatial Variability of Relative Sea-Level Rise in Tianjin, China: Insight from InSAR, GPS, and Tide-Gauge Observations
The Tianjin coastal region in Bohai Bay, Northern China, is increasingly affected by storm-surge flooding which is exacerbated by anthropogenic land subsidence and global sea-level rise (SLR). We use a combination of synthetic aperture radar interferometry (InSAR), continuous GPS (CGPS), and tide-gauge observations to evaluate the spatial variability of relative SLR (RSLR) along the coastline of Tianjin. Land motion obtained by integration of 2 tracks of Sentinel-1 SAR images and 19 CGPS stations shows that the recent land subsidence in Tianjin downtown is less than 8 mm/yr, which has significantly decreased with respect to the last 50 years (up to 110 mm/yr in the 1980s). This might benefit from the South-to-North Water Transfer Project which has provided more than 1.8 billion cubic meters of water for Tianjin city since 2014 and reduced groundwater consumption. However, subsidence centers have shifted to suburbs, especially along the coastline dominated by reclaimed harbors and aquaculture industry, with localized subsidence up to 170 mm/yr. Combining InSAR observations with sea level records from tide-gauge stations reveals spatial variability of RSLR along the coastline. We find that, in the aquaculture zones along the coastline, the rates of land subsidence are as high as 82 mm/yr due to groundwater extraction for fisheries, which subsequently cause local sea levels to rise nearly 30 times faster than the global average. New insights into land subsidence and local SLR could help the country's regulators to make decisions on ensuring the sustainable development of the coastal aquaculture industry
THE VALUE OF CHIEF DATA OFFICER PRESENCE ON FIRM PERFORMANCE
In the era of big data, there are more and more organizations trying to establish a new breed of executive, Chief Data Officer (CDO), to identify new business opportunity from data assets and optimize corporate revenue. However, the relationship between CDO presence and firm’s financial performance has not been rigorously studied and validated in literature. Based on upper echelon theory and strategic change perspectives, we examined the impact of pre-performance on the CDO appointment, as well as the CDO presence on post-performance. We collected a multi-industry dataset of 68 firms with a CDO position. The results show that the return on assets (ROA) is positively related to CDO appointment, while, market to book ratio (M/B) is negatively related to CDO appointment. In addition, we found that firms with CDO have superior financial performance than their peers who do not. This study provides an initial step towards understanding the empirical linkages between CDO presence and firm performance
3D Super-Resolution Imaging Method for Distributed Millimeter-wave Automotive Radar System
Millimeter-wave (mmW) radar is widely applied to advanced autopilot
assistance systems. However, its small antenna aperture causes a low imaging
resolution. In this paper, a new distributed mmW radar system is designed to
solve this problem. It forms a large sparse virtual planar array to enlarge the
aperture, using multiple-input and multiple-output (MIMO) processing. However,
in this system, traditional imaging methods cannot apply to the sparse array.
Therefore, we also propose a 3D super-resolution imaging method specifically
for this system in this paper. The proposed method consists of three steps: (1)
using range FFT to get range imaging, (2) using 2D adaptive diagonal loading
iterative adaptive approach (ADL-IAA) to acquire 2D super-resolution imaging,
which can satisfy this sparsity under single-measurement, (3) using constant
false alarm (CFAR) processing to gain final 3D super-resolution imaging. The
simulation results show the proposed method can significantly improve imaging
resolution under the sparse array and single-measurement
Emergence of the periodic oscillatory modulation in time-like nucleon form factors
We have studied the oscillatory behavior exhibited in the timelike
electromagnetic form factors of nucleons by considering the final-state
interaction effect. This mechanism introduces the Jost function of
pair into the time-like form factors with the help of the distorted-wave Born
approximation. Using a simple square-well potential, the contribution from the
final-state interaction in our approach is naturally damped oscillatory, which
can explain the experimental data very nicely. This scenario seems to be
universal considering that it also reproduces well the threshold enhancements
on the cross sections for , , and
.Comment: 6 pages, 2 figure
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Water-Soluble Flexible Organic Frameworks That Include and Deliver Proteins.
Four water-soluble hydrazone-based three-dimensional (3D) flexible organic frameworks FOF-1-4 have been synthesized from a semirigid tetracationic tetraaldehyde and four flexible dihydrazides. 1H NMR spectroscopy indicated the quantitative formation of FOF-1-4 in D2O, while dynamic light scattering experiments revealed that, depending on the concentration, these porous frameworks display hydrodynamic diameters ranging from 50 to 120 nm. The porosity of the frameworks is confirmed by ethanol vapor adsorption experiments of the solid samples as well as the high loading capacity for a 2.3 nm porphyrin guest in water. The new water-soluble frameworks exhibit low cytotoxicity and form inherent pores with diameters of 5.3 or 6.7 nm, allowing rapid inclusion of proteins such as bovine serum albumin and green and orange fluorescent proteins, and efficient delivery of the proteins into normal and cancer cells. Flow cytometric analysis reveals percentages of the delivered cells up to 99.8%
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