2,230 research outputs found
Public Expenditure and Poverty Reduction in the Southern United States
The objective of this research was to analyze the effects of education, health and hospital, parks and recreation, and public welfare expenditures on poverty, focusing particularly on how these relationships change over space and time. Government expenditure on parks and recreation has been the single most effective government expenditure category over time, although the marginal effects of the government expenditure on poverty alleviation have weakened over time. Clusters of the highest marginal effects of government expenditures on poverty reduction were identified for each time period using geographically weighted regression (GWR) and analysis of local indicators of spatial association (LISA)government expenditure, GWR, poverty, southern United States, Community/Rural/Urban Development,
Note on primitive disk complexes
Given a Heegaard splitting of the -sphere, the primitive disk complex is
defined to be the full subcomplex of the disk complex for one of the
handlebodies of the splitting. It is an open question whether the primitive
disk complex is connected or not when the genus of the splitting is greater
than three. In this note, we prove that a quotient of the primitive disk
complex, called the homotopy primitive disk complex, is connected.Comment: 6 pages, 2 figure
Cilia action in islets: Lessons from mouse models
Primary cilia as a signaling organelle have garnered recent attention as a regulator of pancreatic islet function. These rod-like sensors exist on all major islet endocrine cell types and transduce a variety of external cues, while dysregulation of cilia function contributes to the development of diabetes. The complex role of islet primary cilia has been examined using genetic deletion targeting various components of cilia. In this review, we summarize experimental models for the study of islet cilia and current understanding of mechanisms of cilia regulation of islet hormone secretion. Consensus from these studies shows that pancreatic cilia perturbation can cause both endocrine and exocrine defects that are relevant to human disease. We discuss future research directions that would further elucidate cilia action in distinct groups of islet cells, including paracrine and juxtacrine regulation, GPCR signaling, and endocrine-exocrine crosstalk
Nitrogen doping of carbon nanoelectrodes for enhanced control of DNA translocation dynamics
Controlling the dynamics of DNA translocation is a central issue in the
emerging nanopore-based DNA sequencing. To address the potential of heteroatom
doping of carbon nanostructures to achieve this goal, herein we carry out
atomistic molecular dynamics simulations for single-stranded DNAs translocating
between two pristine or doped carbon nanotube (CNT) electrodes. Specifically,
we consider the substitutional nitrogen doping of capped CNT (capCNT)
electrodes and perform two types of molecular dynamics simulations for the
entrapped and translocating single-stranded DNAs. We find that the
substitutional nitrogen doping of capCNTs stabilizes the edge-on nucleobase
configurations rather than the original face-on ones and slows down the DNA
translocation speed by establishing hydrogen bonds between the N dopant atoms
and nucleobases. Due to the enhanced interactions between DNAs and N-doped
capCNTs, the duration time of nucleobases within the nanogap was extended by up
to ~ 290 % and the fluctuation of the nucleobases was reduced by up to ~ 70 %.
Given the possibility to be combined with extrinsic light or gate voltage
modulation methods, the current work demonstrates that the substitutional
nitrogen doping is a promising direction for the control of DNA translocation
dynamics through a nanopore or nanogap based of carbon nanomaterials.Comment: 11 pages, 4 figure
Extreme coefficients in Geographically Weighted Regression and their effects on mapping
This study deals with the issue of extreme coefficients in geographically weighted regression (GWR) and their effects on mapping coefficients using three datasets with different spatial resolutions. We found that although GWR yields extreme coefficients regardless of the resolution of the dataset or types of kernel function, 1) the GWR tends to generate extreme coefficients for less spatially dense datasets, 2) coefficient maps based on polygon data representing aggregated areal units are more sensitive to extreme coefficients, and 3) coefficient maps using bandwidths generated by a fixed calibration procedure are more vulnerable to the extreme coefficients than adaptive calibration.extreme coefficient, fixed and adaptive calibrations, geographically weighted regression, Mapping, Research Methods/ Statistical Methods,
Renormalization of Complex Networks with Partition Functions
While renormalization groups are fundamental in physics, renormalization of
complex networks remains vague in its conceptual definition and methodology.
Here, we propose a novel strategy to renormalize complex networks. Rather than
resorting to handling the bare structure of a network, we overlay it with a
readily renormalizable physical model, which reflects real-world scenarios with
a broad generality. From the renormalization of the overlying system, we
extract a rigorous and simple renormalization group transformation of arbitrary
networks. In this way, we obtain a transparent, model-dependent physical
meaning of the network renormalization, which in our case is a scale
transformation preserving the transition dynamics of low-density particles. We
define the strength of a node in accordance with the physical model and trace
the change of its distribution under our renormalization process. This analysis
demonstrates that the strength distributions of scale-free networks remain
scale-invariant, whereas those of homogeneous random networks do not.Comment: 5 pages, 4 figure
Bacterial community analysis in upflow multilayer anaerobic reactor (UMAR) treating high-solids organic wastes
A novel anaerobic digestion configuration, the upflow multi-layer anaerobic reactor (UMAR), was developed to treat high-solids organic wastes. The UMAR was hypothesized to form multi-layer along depth due to the upflow plug flow; use of a recirculation system and a rotating distributor and baffles aimed to assist treating high-solids influent. The chemical oxygen demand (COD) removal efficiency and methane (CH4) production rate were 89% and 2.10 L CH4/L/day, respectively, at the peak influent COD concentration (110.4 g/L) and organic loading rate (7.5 g COD/L/day). The 454 pyrosequencing results clearly indicated heterogeneous distribution of bacterial communities at different vertical locations (upper, middle, and bottom) of the UMAR. Firmicutes was the dominant (>70%) phylum at the middle and bottom parts, while Deltaproteobacteria and Chloroflexi were only found in the upper part. Potential functions of the bacteria were discussed to speculate on their roles in the anaerobic performance of the UMAR system
Experimental observation of hidden Berry curvature in inversion-symmetric bulk 2H-WSe2
We investigate the hidden Berry curvature in bulk 2H-WSe2 by utilizing the
surface sensitivity of angle resolved photoemission (ARPES). The symmetry in
the electronic structure of transition metal dichalcogenides is used to
uniquely determine the local orbital angular momentum (OAM) contribution to the
circular dichroism (CD) in ARPES. The extracted CD signals for the K and K'
valleys are almost identical but their signs, which should be determined by the
valley index, are opposite. In addition, the sign is found to be the same for
the two spin-split bands, indicating that it is independent of spin state.
These observed CD behaviors are what are expected from Berry curvature of a
monolayer of WSe2. In order to see if CD-ARPES is indeed representative of
hidden Berry curvature within a layer, we use tight binding analysis as well as
density functional calculation to calculate the Berry curvature and local OAM
of a monolayer WSe2. We find that measured CD-ARPES is approximately
proportional to the calculated Berry curvature as well as local OAM, further
supporting our interpretation.Comment: 6 pages, 3 figure
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