88 research outputs found

    A Theory of Entrepreneurial Overconfidence, Effort, and Firm Outcomes

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    We present a theory of entrepreneurial behavior that explores the relationship between overconfidence and successful firm outcomes, such as acquisition or IPO. In our model, increasing overconfidence produces two conflicting effects on the probability of a successful outcome: it not only induces an entrepreneur to increase the riskiness of a venture (which lowers the likelihood of successful exit), but also drives higher entrepreneurial effort, increasing likelihood of a successful exit. Due to this conflict, a kinked or U-shaped relationship may exist between overconfidence and positive outcomes. Furthermore, our model suggests that increased outside equity mitigates the effects of overconfidence

    Cabbage pest management

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    "In Missouri, about 600 acres of cabbage and 200 acres of broccoli, cauliflower, and collards are planted each year. The majority of this acreage is in commercial production in the St. Louis and Bootheel areas. Small truck farms and home gardens produce cabbage and related cole crops throughout the state."--First page.James R. Davis, K.D. Biever, W.S. Craig, and M.L. Fairchild (Department of Entomology)New 8/85/6

    Enhanced cytotoxicity with methotrexate in conjunction with hypoxanthine in L1210 cells in culture

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    By inhibiting dihydrofolate reductase, methotrexate (MTX) depletes cellular stores of reduced folates, resulting in the inhibition of DNA and RNA synthesis. Inhibition of RNA synthesis arrests cells in the G 1 phase of the cell cycle, preventing these cells from entering S phase and rendering them insensitive to MTX. Because MTX cytotoxicity can be enhanced by concurrent administration of hypoxanthine (HX), we examined the hypothesis that this modulation can allow normal rates of RNA synthesis and cell cycle progression from G 1 to S phase. For L1210 cells exposed to MTX for 12 h or 24 h, the addition of HX enhanced the cytotoxicity of MTX; however, no enhancement was observed with a 6-h exposure. Inhibition of RNA synthesis by MTX was prevented by concurrent administration of HX. The effect of HX on cell cycle progression was first examined using flow cytometry, which indicated that MTX treatment alone or with concurrent HX caused a buildup of cells with aG 1 content of DNA. Because this technique may fail to distinguish between cells in late G 1 phase, the G 1 /S border, or early S, the method of premature chromosome condensation was used to determine cell cycle position based on chromatin morphology. A shift to a higher degree of chromatin decondensation was observed when HX was coadministered with MTX during a 12-h exposure, suggesting progression from G 1 towards S. This correlated with the enhancement of MTX cytotoxicity by HX after 12 h exposure. The results of these studies suggest that HX potentiates MTX cytotoxicity by maintaining RNA synthesis, allowing cells that mightordinarily be arrested in G 1 to progress into the cytotoxic S phase.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46918/1/280_2004_Article_BF00254176.pd

    Rare coding variants in PLCG2, ABI3, and TREM2 implicate microglial-mediated innate immunity in Alzheimer's disease

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    We identified rare coding variants associated with Alzheimer’s disease (AD) in a 3-stage case-control study of 85,133 subjects. In stage 1, 34,174 samples were genotyped using a whole-exome microarray. In stage 2, we tested associated variants (P<1×10-4) in 35,962 independent samples using de novo genotyping and imputed genotypes. In stage 3, an additional 14,997 samples were used to test the most significant stage 2 associations (P<5×10-8) using imputed genotypes. We observed 3 novel genome-wide significant (GWS) AD associated non-synonymous variants; a protective variant in PLCG2 (rs72824905/p.P522R, P=5.38×10-10, OR=0.68, MAFcases=0.0059, MAFcontrols=0.0093), a risk variant in ABI3 (rs616338/p.S209F, P=4.56×10-10, OR=1.43, MAFcases=0.011, MAFcontrols=0.008), and a novel GWS variant in TREM2 (rs143332484/p.R62H, P=1.55×10-14, OR=1.67, MAFcases=0.0143, MAFcontrols=0.0089), a known AD susceptibility gene. These protein-coding changes are in genes highly expressed in microglia and highlight an immune-related protein-protein interaction network enriched for previously identified AD risk genes. These genetic findings provide additional evidence that the microglia-mediated innate immune response contributes directly to AD development

    New insights into the genetic etiology of Alzheimer's disease and related dementias

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    Characterization of the genetic landscape of Alzheimer's disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/'proxy' AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele
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