912 research outputs found
Recent Trends in Household Income Dynamics for the United States, Germany and Great Britain
This paper examines the recent trends in household income volatility in the United States, Germany and Great Britain, and compares household income volatility with individual income volatility. I estimate a formal error components model using the Cross-national Equivalence File from 1979 to 2004. I find that household income volatility, measured by the transitory variance of household income, accounts for more than half of the total income variance for all three countries. Despite the differences in the total household income variances among the three countries, the permanent variances converges since the late 1990s.Household Income, Income Volatility, Permanent Inequality, Cross-National Comparison
Achieving the Heisenberg limit in quantum metrology using quantum error correction
Quantum metrology has many important applications in science and technology,
ranging from frequency spectroscopy to gravitational wave detection. Quantum
mechanics imposes a fundamental limit on measurement precision, called the
Heisenberg limit, which can be achieved for noiseless quantum systems, but is
not achievable in general for systems subject to noise. Here we study how
measurement precision can be enhanced through quantum error correction, a
general method for protecting a quantum system from the damaging effects of
noise. We find a necessary and sufficient condition for achieving the
Heisenberg limit using quantum probes subject to Markovian noise, assuming that
noiseless ancilla systems are available, and that fast, accurate quantum
processing can be performed. When the sufficient condition is satisfied, a
quantum error-correcting code can be constructed which suppresses the noise
without obscuring the signal; the optimal code, achieving the best possible
precision, can be found by solving a semidefinite program.Comment: 16 pages, 2 figures, see also arXiv:1704.0628
Evaluating Urban Expansion Using Integrated Remote Sensing and GIS technique: A Case Study in Greater Chengdu, China
The overall goal of this thesis is to better understand changes in the spatial pattern of urban growth and its impact on landscape configuration by conducting a case study in Greater Chengdu, an inland megacity in China. The objectives are as follows: 1) Quantifying changes in the spatial pattern of the study area between 2003 and 2013; 2) Evaluating the degree of urban sprawl over that period; 3) Evaluating urban expansion dynamics; and 4) Examining and defining the types of urban growth. Satellite imagery was employed to distinguish and identify different land surface categories. Integrated remote sensing and GIS (Geographic Information System) technique was used to analyse both qualitative and quantitative perspectives regarding the objectives. The results indicate that the urban area of Greater Chengdu doubled from 525.5 km2 to 1191.85 km2 during 2003 to 2013. The geographic footprint demonstrates that the distribution of the built-up area was dispersed and continues to grow more dispersed. The dominant type of urban growth is outward expansion, by which the city grew within a 10 km to 25 km radius surrounding the city center. A substantial infill phenomenon exists between a 5 km and 10 km radius from the city center. The urban core boundary expanded outward by 5 km, while the fringe of suburban area expanded outward by 10 km during the time period, which both indicate a substantial outward expansion over the city. The significant contribution of this study could benefit to many aspects such as comparative studies between cities or continuous studies relevant to urban growth
Less Than Equal: Racial Disparities in Wealth Accumulation
When it comes to economic gaps between whites and communities of color in the United States, income inequality tells part of the story. But let's not forget about wealth. Wealth isn't just money in the bank, it's insurance against tough times, tuition to get a better education and a better job, savings to retire on, and a springboard into the middle class. In short, wealth translates into opportunity
Private Transfers, Race, and Wealth
Examines racial/ethnic disparities in private transfers of financial support from extended families and friends, large gifts, and inheritances, as well as net support received after transfers given; their impact on wealth disparities; and implications
A High-Frequency, Volumetric Trading Strategy
We test a candidate high-frequency investment strategy, which utilizes the time series of price, volume and a novel interaction term to forecast intra-day returns over a continuous 101 day period from January 4 to May 28, 2010. The strategy uses minute-level data calculate regression coefficients from one-day for the purposes of trading the following day, thereby avoiding data snooping bias. Finally regressing the daily returns against the Fama-French Four Market Factors reveals significant alphas for more than half of the traded stocks
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Effectively Settling SMEs financing Difficulty with Warehouse Receipt-a Case from China
SMEs financing is a difficult problem in the world, and it is more difficult in China. The highlight of our paper is that it offers a route which could settle the difficult problem but loan on credit. There are three platforms which can effectively settle SMEs financing difficulty with warehouse receipt. Platform 1 is a warehouse receipt management platform which manages SMEs movable property. Platform 2 is a P2P platform, or warehouse receipt financing platform. Platform 3 is a transaction platform of warehouse receipt. Future works have been put in the end
Effect of n-3 polyunsaturated fatty acids on dopaminergic neurons in substantia nigra, brain inflammatory response and behavior in mice with Parkinsonâs disease
Purpose: To examine the effect of n-3 polyunsaturated fatty acids (PUFAs) on dopaminergic neurons in substantia nigra, intracerebral inflammatory response and ethology in mice with Parkinsonâs disease (PD).
Methods: Four groups of male C57BL/6 mice (n = 48) were used: normal control, negative control, n3PUFA, and Madopa groups. Except for normal control group, all groups were given 6- hydroxydopamine hydrochloride (6-OHDA) to establish Parkinsonâs mice model. The expressions of tyrosine hydroxylase (TH) and calcium-binding protein (CB) in substantia nigra dopaminergic neurons were determined with immunohistochemistry and Western blot. The contents of nitric oxide (NO), tumor necrosis factor (TNF-α) and interferon Îł (IFN-Îł) (indices of intracerebral inflammatory response) were measured. Tremor paralysis, moving grid number, standing times, swimming ability, and the number of rollers in each group were observed as indices of ethology.
Results: The number of TH and CB-positive neurons in the substantia nigra of n-3PUFA-treated mice was significantly increased, relative to those in Madopa-treated mice (p < 0.05). The expressions of TH and CB proteins in substantia nigra in n-3PUFA group were markedly higher than the corresponding expressions in Madopa-treated mice (p < 0.05). Decreased levels of NO, TNF-α and IFN-γ levels were seen in 3PUFA group, when compared to mice in Madopa group, but higher behavioral scores were obtained in n-3PUFA-treated mice, relative to Madopa-treated mice (p < 0.05).
Conclusion: The n-3PUFAs protect substantia nigra compact dopaminergic neurons against Parkinsonâs disease, alleviate immune inflammation, and improve the coordination of limb movement. Thus, n-3PUFAs have potential therapeutic application in the management of Parkinsonâs disease
A Possible Optical Quasi-periodic Oscillation of 134~day in the Radio-loud Narrow-line Seyfert 1 Galaxy TXS 1206+549 at
Here we report an optical quasi-periodic oscillation (QPO) with a period of
134~day detected in g- and r-band light curves of a narrow-line Seyfert 1
galaxy TXS 1206+549 at redshift of 1.34 with the data from the Zwicky Transient
Facility (ZTF) observations. After considering the trial factor, the
significance levels in the two bands are 3.1 and 2.6 ,
respectively. The QPO signal presents about 10 cycles ranging from 2018 March
to 2021 December lasting 4 year. A near-sinusoidal profile also appears
in the folded light curves by a phase-resolved analysis. Interestingly, in the
simultaneous light curve as the time scale of ZTF observations, a potential
periodic signal with similar period is detected in the o-band light curve from
the Asteroid Terrestrial-Impact Last Alert System data, additionally a weak
peak is also detected at the similar period in the gamma-ray light curve
obtained from the \emph{Fermi} Gamma-ray Space Telescope data. Some potential
origins of periodicities in active galactic nuclei are discussed for the QPO
reported here.Comment: 9 pages, 5 figures, 1 tables. Accepted by Ap
Mechanism and application of Lactobacillus in type 2 diabetes-associated periodontitis
Type 2 diabetes mellitus (T2DM) accelerates the progression of periodontitis through diverse pathways. Abnormal immune responses, excessive activation of inflammation, increased levels of advanced glycation end products, and oxidative stress have defined roles in the pathophysiological process of T2DM-associated periodontitis. Furthermore, in the periodontium of diabetic individuals, there are high levels of advanced glycation end-products and glucose. Meanwhile, progress in microbiomics has revealed that dysbacteriosis caused by T2DM also contributes to the progression of periodontitis. Lactobacillus, owing to its fine-tuning function in the local microbiota, has sparked tremendous interest in this field. Accumulating research on Lactobacillus has detailed its beneficial role in both diabetes and oral diseases. In this study, we summarize the newly discovered mechanisms underlying Lactobacillus-mediated improvement of T2DM-associated periodontitis and propose the application of Lactobacillus in the clinic
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