35,744 research outputs found
Characteristics of Alveolar Bone Marrow Cells from Patients Undergoing Dental Extractions or Dental Implant Therapy
Alveolar bone marrow stromal cells (aBMSCs) play important roles in craniofacial wound healing. To establish an easy, efficient and reliable method to harvest aBMSCs, we compared three different methods: extraction socket aspiration, osteotomy aspiration and bone core digestion. Samples of aBMSC were collected from two groups of subjects. Group 1 (dental extraction): after dental extraction, 22.5-gauge needles were used to collect 0.5-1cc marrow aspirate. Group 2 (dental implant): during implant surgeries, bone core and 0.5-1cc marrow aspirate were obtained from the osteotomy. Samples were cultured in petri dishes and attached cells were expanded. The population doubling time (PDT), surface markers, and osteogenic differentiation potential of these cells were studied. In total 12 subjects were enrolled in the study. The success rates of generating aBMSCs from extraction socket aspiration, osteotomy aspiration and bone core digestion were 42.8% (3/7), 40% (2/5) and 80% (4/5), respectively. Cells from extraction socket aspiration had the fastest proliferation rate among the three sample types, followed by bone core and osteotomy aspiration, as shown in PDTs and DNA fold changes. After isolation and expansion, all the aBMSCs expressed high levels of CD 73, CD90, and CD105, however, the expression of CD146 varied among the cells. Cells derived from bone core had the highest ALP activity after osteogenic induction, followed by cells from osteotomy aspiration, and then extraction aspiration. Taken together, bone core samples obtained during implant surgery is a more reliable source for generating aBMSCs and aBMSCs harvested from different methods may have different characteristics
Jobs, working hours, and remuneration packages for migrants and urban residents
In this chapter we look at the working conditions and remuneration of migrants versus incumbent urban
residents in China in the 2008 wave of the RUMiCI project. We find that the average hourly compensation
for an urban worker is more than double that of migrants. Inequality of non-wage compensation is higher
than that of hourly wages, mainly because urban workers are much more likely to benefit from various
insurance schemes than migrants. Nearly three-quarters of the hourly compensation differences can be
explained by observable characteristics. Returns to education and experience are lower for the migrants. They
also have less education and accumulate less experience, perchance due to the temporary nature of the
migration. We find strong differences between cities. For example, total compensation in Wuxi, Hefei,
Ningbo and Chengdu is roughly the same for migrants as for the equivalent urban city dweller with the same
characteristics. This equal treatment is also reflected in non-wage remuneration components. Yet in
Chongqing and several other cities, a migrant is paid less than half the equivalent urban city dweller. This
suggests that some cities ‘compete’ for migrants whilst others do not, and it also suggests that there are many
city dwellers who would be better off if they move to other cities.Australian Research Council, AusAID, IZA, Ford Foundatio
Weakly-bound Hadronic Molecule near a 3-body Threshold
The X(3872) seems to be a loosely-bound hadronic molecule whose constituents
are two charm mesons. A novel feature of this molecule is that the mass
difference of the constituents is close to the mass of a lighter meson that can
be exchanged between them, namely the pion. We analyze this feature in a simple
model with spin-0 mesons only. Various observables are calculated to
next-to-leading order in the interaction strength of the exchanged meson.
Renormalization requires summing a geometric series of next-to-leading order
corrections. The dependence of observables on the ultraviolet cutoff can be
removed by renormalizations of the mass of the heaviest meson, the coupling
constant for the contact interaction between the heavy mesons, and
short-distance coefficients in the operator product expansion. The
next-to-leading order correction has an unphysical infrared divergence at the
threshold of the two heavier mesons that can be eliminated by a further
resummation that takes into account the nonzero width of the heaviest meson.Comment: 37 pages, 13 figures, submitted to Phys.Rev.
Empirical Modeling of Ducting Effects on a Mobile Microwave Link Over a Sea Surface
In this paper, signal enhancement due to the ducts over a sea surface is experimentally investigated and modeled. The investigation is carried out through the study of air-to-ground mobile microwave links over a tropical ocean with low airborne altitudes (0.37 - 1.83 km) at C band (5.7 GHz). The distance-dependence of the ducting induced enhancement (with reference to the free-space propagation) is linearly modeled, and the physical variations of the ducts are found to be Gaussian distributed. Empirical ducting coefficients and parameters for the Gaussian function are estimated and provided for the prediction of the distance-dependent signal enhancement due to the ducts in similar scenarios
Joint Video and Text Parsing for Understanding Events and Answering Queries
We propose a framework for parsing video and text jointly for understanding
events and answering user queries. Our framework produces a parse graph that
represents the compositional structures of spatial information (objects and
scenes), temporal information (actions and events) and causal information
(causalities between events and fluents) in the video and text. The knowledge
representation of our framework is based on a spatial-temporal-causal And-Or
graph (S/T/C-AOG), which jointly models possible hierarchical compositions of
objects, scenes and events as well as their interactions and mutual contexts,
and specifies the prior probabilistic distribution of the parse graphs. We
present a probabilistic generative model for joint parsing that captures the
relations between the input video/text, their corresponding parse graphs and
the joint parse graph. Based on the probabilistic model, we propose a joint
parsing system consisting of three modules: video parsing, text parsing and
joint inference. Video parsing and text parsing produce two parse graphs from
the input video and text respectively. The joint inference module produces a
joint parse graph by performing matching, deduction and revision on the video
and text parse graphs. The proposed framework has the following objectives:
Firstly, we aim at deep semantic parsing of video and text that goes beyond the
traditional bag-of-words approaches; Secondly, we perform parsing and reasoning
across the spatial, temporal and causal dimensions based on the joint S/T/C-AOG
representation; Thirdly, we show that deep joint parsing facilitates subsequent
applications such as generating narrative text descriptions and answering
queries in the forms of who, what, when, where and why. We empirically
evaluated our system based on comparison against ground-truth as well as
accuracy of query answering and obtained satisfactory results
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