543 research outputs found

    Estimation of Poverty Transition Matrices with Noisy Data

    Get PDF
    This paper investigates potential measurement error biases in estimated poverty transition matrices. We compare transition matrices based on survey expenditure data to transition matrices based on measurement-error-free simulated expenditure. The simulation model uses estimates that correct for measurement error in expenditure. This dynamic model needs error-free initial conditions that can not be derived from these estimates. We provide bounds on the initial-conditions parameters, when these initial conditions are obtained by projection, and we also obtain initial conditions on the assumption that there is no time-constant measurement error. We ?nd that for both estimates of the initial conditions measurement error in expenditure data magni?es economic mobility in and out of poverty. Roughly 44% of households initially in poverty at time t??1 are found to be out of poverty at time t using expenditure data from the Korean Labor and Income Panel Study (KLIPS). However, when we remove measurement error through a model-based simulation, only between 32 and 40% of households initially in poverty are found to be out of poverty.Measurement error, Economic mobility, Transition matrix JEL Code: C81, I32, O15

    Analysis of interactive fixed effects dynamic linear panel regression with measurement error

    Get PDF
    This paper studies a simple dynamic panel linear regression model with interactive fixed effects in which the variable of interest is measured with error. To estimate the dynamic coefficient, we consider the least-squares minimum distance (LS-MD) estimation method.

    Interplay between spin density wave and π\pi phase shifted superconductivity in the Fe pnictide superconductors

    Full text link
    We explore if the phase separation or coexistence of the spin density wave (SDW) and superconductivity (SC) states has any relation to the incommensurability of the SDW in the Fe pnictide superconductors. A systematic method of determining the phase separation or coexistence was employed by computing the anisotropy coefficient β\beta from the the 4th order terms of the Ginzburg--Landau (GL) expansion of the free energy close to the tricritical/tetracritical point. It was complemented by the self-consistent numerical iterations of the gap equations to map out the boundaries between the phase separation and coexistence of the SDW and SC phases, and between commensurate (C) and incommensurate (IC) SDW in the temperature--doping plane. Our principal results for the sign reversed ss-wave pairing SC, in terms of the multicritical temperature, TcT_c, the phase separation/coexistence boundary between the SDW and SC, TT^*, and the boundary between C/IC SDW, TMT_M^*, are: (a) IC-SDW and SC coexist for Tc<TT_c < T^* and phase separate otherwise, (b) SDW takes the C form for Tc>TMT_c>T_M^* and IC form for Tc<TMT_c<T_M^*, and (c) the thermodynamic first order phase transition intervenes in between the C-SDW and IC-SDW boundary for large TM0T_M^0, where TM0T_M^0 is the SDW transition temperature at zero doping, T=0.35 TM0T^*=0.35 ~T_M^0 and TM=0.56 TM0T_M^*=0.56\ T_M^0. The intervention makes the phase diagram more complicated than previously reported. By contrast no coexistence was found for the equal sign pairing SC. These results will be compared with the experimental reports in the Fe pnictide superconductors.Comment: 9 pages, 4 figures, Submitted to Phys.Rev.

    Development of translational models for intervertebral disc degeneration using a comparative approach for canine and human patients

    Get PDF
    Intervertebral discs (IVDs) are unique musculoskeletal tissues within functional spinal unit organs comprising the spinal column that distribute loads and allow complex movements for vertebrates. IVD degeneration has been closely associated with manifestations of symptomatic IVD disease (IVDD). IVDD spontaneously occurs in canine and human populations. As such, dogs can serve as highly relevant and ethical preclinical models for both human and canine IVDD. Chondrodystrophic (CD) and non-chondrodystrophic (NCD) breeds of dogs show different phenotypes of IVDD, each of which mimic phenotypes described for human patients. The main goal for this PhD research was to develop and validate canine models for human IVDD with a focus on distinguishing molecular characteristics of key disease phenotypes. Using biomarkers associated with inflammation and degradation, IVD health and disease were characterized for the two species. Taken together, this body of work suggests that CD and NCD dogs demonstrate distinctly different biomarker profiles in both health and disease that represent key human IVDD phenotypes such that they can be used as effective models for translational research towards clinical diagnosis, prevention, and treatment strategies for canine and human degenerative disc disorders.Includes bibliographical references

    Microbial Changes and Host Response in F344 Rat Colon Depending on Sex and Age Following a High-Fat Diet

    Get PDF
    Gut microbiota, an important component that affects host health, change rapidly and directly in response to altered diet composition. Recently, the role of diet–microbiome interaction on the development of colon cancer has been the focus of interest. Colon cancer occurs more frequently in an aged population, and in males. However, the effect of dietary changes on the gut microbiome has been studied mainly in young males, even though it may vary with age and sex. The aim of this study was to investigate microbial changes and host response in the colons of male and female 6-week-old (young) and 2-year-old (old) Fisher-344 rats exposed to a high-fat diet (HFD). Our results showed that exposure to HFD for 8 weeks decreased the species richness of microbiota (Chao1) and increased Firmicutes/Bacteroidetes ratio only in aged rats, and not in young rats. Sex differences underlying the alteration by HFD in the gut microbiome were observed in the microbiome of aged rats. For instance, the abundance ratio of Akkermansia muciniphila and Desulfovibrio spp. increased in response to HFD in young rats and female aged rats, but not in male aged rats. Histological inflammation and cell proliferation of colon mucosa (indexed by Ki67) were significantly increased by HFD even in young rats; aged rats showed significantly higher cell proliferation in the HFD group than in the control. The HFD-induced decrease of species richness and the increase in specific species (Desulfovibrio spp. and Clostridium lavalense), which produce carcinogenic compounds such as H2S and N-nitroso compounds, were significantly correlated with Ki67 index. In colon mucosa, the concentration of myeloperoxidase was increased by HFD only in males, and not in females. In conclusion, the results suggest a link between HFD-induced gut dysbiosis (particularly the low species richness and high abundance ratios of Desulfovibrio spp. and C. lavalense) and cell proliferation of colon mucosa (indicated by Ki67 IHC). In addition, sex differences influence the response of gut microbiome to HFD particularly in old age. Such sex differences in the gut microbiota might be related to sex differences in inflammation in the colon mucosa

    Validation of Alternating Kernel Mixture Method: Application to Tissue Segmentation of Cortical and Subcortical Structures

    Get PDF
    This paper describes the application of the alternating Kernel mixture (AKM) segmentation algorithm to high resolution MRI subvolumes acquired from a 1.5T scanner (hippocampus, n = 10 and prefrontal cortex, n = 9) and a 3T scanner (hippocampus, n = 10 and occipital lobe, n = 10). Segmentation of the subvolumes into cerebrospinal fluid, gray matter, and white matter tissue is validated by comparison with manual segmentation. When compared with other segmentation methods that use traditional Bayesian segmentation, AKM yields smaller errors (P < .005, exact Wilcoxon signed rank test) demonstrating the robustness and wide applicability of AKM across different structures. By generating multiple mixtures for each tissue compartment, AKM mimics the increased variation of manual segmentation in partial volumes due to the highly folded tissues. AKM's superior performance makes it useful for tissue segmentation of subcortical and cortical structures in large-scale neuroimaging studies

    17β-estradiol reduces inflammation and modulates antioxidant enzymes in colonic epithelial cells

    Get PDF
    Background/Aims: Estrogen is known to have protective effect in colorectal cancer development. The aims of this study are to investigate whether estradiol treatment reduces inflammation in CCD841CoN, a female human colonic epithelial cell line and to uncover underlying mechanisms of estradiol effects. Methods: 17 beta-Estradiol (E2) effect was measured by Western blot after inducing inflammation of CCD841CoN by tumor necrosis factor alpha (TNF-alpha). Expression levels of estrogen receptor alpha (ER alpha) and beta (ER beta), cyclooxygenase-2 (COX-2), nuclear factor-kappa B (NF-kappa B), heme oxygenase-1 (HO-1), and NAD(P)H-quinone oxidoreductase-1 (NQO-1) were also evaluated. Results: E2 treatment induced expression of ERO but did not increase that of ER alpha. E2 treatment for 48 hours significantly elevated the expression of anti-oxidant enzymes, HO-1 and NQO-1. TNF-alpha treatment significantly increased the level of activated NF-kappa B (p < 0.05), and this increase was significantly suppressed by treatment of to nM of E2 (p < 0.05). E2 treatment ameliorated TNF-alpha-induced COX-2 expression and decrease of HO-1 expression. 4-(2-phenyl-5,7-bis(trifluoromethyl) pyrazolo(1,5-a)pyrimidin-3-yl)phenol (PHTPP), antagonist of ER beta, removed the inhibitory effect of E2 in the TNF-alpha-induced COX-2 expression (p = 0.05). Conclusions: Estrogen seems to inhibit inflammation in female human colonic epithelial cell lines, through down-regulation of NF-kappa B and COX-2 expression and induction of anti-oxidant enzymes such as HO-1 and NQO-1.

    17β-Estradiol supplementation changes gut microbiota diversity in intact and colorectal cancer-induced ICR male mice

    Get PDF
    The composition of the gut microbiota is influenced by sex hormones and colorectal cancer (CRC). Previously, we reported that 17 beta -estradiol (E2) inhibits azoxymethane/dextran sulfate sodium (AOM/DSS)-induced tumorigenesis in male mice. Here, we investigated whether the composition of the gut microbiota is different between male and female, and is regulated by estrogen as a secondary outcome of previous studies. We established four groups of mice based on the sex and estrogen status [ovariectomized (OVX) female and E2-treated male]. Additionally, three groups of males were established by treating them with AOM/DSS, and E2, after subjecting them to AOM/DSS treatment. The mice were sacrificed at 21 weeks old. The composition of the gut microbiota was analyzed using 16S rRNA metagenomics sequencing. We observed a significant increase in the microbial diversity (Chao1 index) in females, males supplemented with E2, and males treated with AOM/DSS/E2 compared with normal males. In normal physiological condition, sex difference and E2 treatment did not affect the ratio of Firmicutes/Bacteroidetes (F/B). However, in AOM/DSS-treated male mice, E2 supplementation showed significantly lower level of the F/B ratio. The ratio of commensal bacteria to opportunistic pathogens was higher in females and E2-treated males compared to normal males and females subjected to OVX. Unexpectedly, this ratio was higher in the AOM/DSS group than that determined in other males and the AOM/DSS/E2 group. Our findings suggest that estrogen alters the gut microbiota in ICR (CrljOri:CD1) mice, particularly AOM/DSS-treated males, by decreasing the F/B ratio and changing Shannon and Simpson index by supply of estrogen. This highlights another possibility that estrogen could cause changes in the gut microbiota, thereby reducing the risk of developing CRC.
    corecore