1,362 research outputs found

    Estimation of Poverty Transition Matrices with Noisy Data

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    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

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

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    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.

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

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    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.

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

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    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

    Structure-mechanism-based engineering of chemical regulators targeting distinct pathological factors in Alzheimer???s disease

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    The absence of effective therapeutics against Alzheimer???s disease (AD) is a result of the limited understanding of its multifaceted aetiology. Because of the lack of chemical tools to identify pathological factors, investigations into AD pathogenesis have also been insubstantial. Here we report chemical regulators that demonstrate distinct specificity towards targets linked to AD pathology, including metals, amyloid-?? (A??), metal-A??, reactive oxygen species, and free organic radicals. We obtained these chemical regulators through a rational structure-mechanism-based design strategy. We performed structural variations of small molecules for fine-tuning their electronic properties, such as ionization potentials and mechanistic pathways for reactivity towards different targets. We established in vitro and/or in vivo efficacies of the regulators for modulating their targets??? reactivities, ameliorating toxicity, reducing amyloid pathology, and improving cognitive deficits. Our chemical tools show promise for deciphering AD pathogenesis and discovering effective drugs.ope

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

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    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

    The Draft Genome of an Octocoral, Dendronephthya gigantea

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    Coral reefs composed of stony corals are threatened by global marine environmental changes. However, soft coral communities of octocorallian species, appear more resilient. The genomes of several cnidarians species have been published, including from stony corals, sea anemones, and hydra. To fill the phylogenetic gap for octocoral species of cnidarians, we sequenced the octocoral, Dendronephthya gigantea, a nonsymbiotic soft coral, commonly known as the carnation coral. The D. gigantea genome size is similar to 276 Mb. A high-quality genome assembly was constructed from PacBio long reads (29.85 Gb with 108x coverage) and Illumina short paired-end reads (35.54 Gb with 128x coverage) resulting in the highest N50 value (1.4 Mb) reported thus far among cnidarian genomes. About 12% of the genome is repetitive elements and contained 28,879 predicted protein-coding genes. This gene set is composed of 94% complete BUSCO ortholog benchmark genes, which is the second highest value among the cnidarians, indicating high quality. Based on molecular phylogenetic analysis, octocoral and hexacoral divergence times were estimated at 544 MYA. There is a clear difference in Hox gene composition between these species: unlike hexacorals, the Antp superclass Evx gene was absent in D. gigantea. Here, we present the first genome assembly of a nonsymbiotic octocoral, D. gigantea to aid in the comparative genomic analysis of cnidarians, including stony and soft corals, both symbiotic and nonsymbiotic. The D. gigantea genome may also provide clues to mechanisms of differential coping between the soft and stony corals in response to scenarios of global warming
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