Characterization of a high strain composite material

L'Garde has designed and developed a high-strain composite material consisting of car- bon FIbers embedded in a silicone matrix. The behavior of this material is significantly different from standard composites and the paper presents special test methods to measure the properties of this material. It is found that rule of mixtures estimates are quite accurate for the longitudinal moduli in tension and bending, but less accurate for compression. The Poisson's ratio prediction is also not accurate. Regarding the strength of the composite, it is found that conservative predictions of tensile and compressive strengths can be obtained respectively from the Weibull distribution of the strength of a single fiber combined with a simple bundle theory, and the elastic fiber microbuckling stress

Third quantization: a general method to solve master equations for quadratic open Fermi systems

The Lindblad master equation for an arbitrary quadratic system of n fermions is solved explicitly in terms of diagonalization of a 4n x 4n matrix, provided that all Lindblad bath operators are linear in the fermionic variables. The method is applied to the explicit construction of non-equilibrium steady states and the calculation of asymptotic relaxation rates in the far from equilibrium problem of heat and spin transport in a nearest neighbor Heisenberg XY spin 1/2 chain in a transverse magnetic field.Comment: 24 pages, with 8 eps figures - few minor corrections to the published version, e.g. anti-symmetrizing the matrix given by eq. (27

The Disability Burden Associated With Stroke Emerges Before Stroke Onset and Differentially Affects Blacks: Results From the Health and Retirement Study Cohort

Background. Few longitudinal studies compare changes in instrumental activities of daily living (IADLs) among stroke-free adults to prospectively document IADL changes among adults who experience a stroke. We contrast annual declines in IADL independence for older individuals who remain stroke-free to those for individuals who experienced a stroke. We also assess whether these patterns differ by sex, race, or Southern birthplace. Methods. Health and Retirement Study participants who were stroke-free in 1998 (n = 17,741) were followed through 2010 (average follow-up = 8.9 years) for self- or proxy-reported stroke. We used logistic regressions to compare annual changes in odds of self-reported independence in six IADLs among those who remained stroke-free throughout follow-up (n = 15,888), those who survived a stroke (n = 1,412), and those who had a stroke and did not survive to participate in another interview (n = 442). We present models adjusted for demographic and socioeconomic covariates and also stratified on sex, race, and Southern birthplace. Results. Compared with similar cohort members who remained stroke-free, participants who developed stroke had faster declines in IADL independence and a lower probability of IADL independence prior to the stroke. After a stroke, independence declined at an annual rate similar to those who did not have a stroke. The black-white disparity in IADL independence narrowed poststroke. Conclusion. Racial differences in IADL independence are apparent long before stroke onset. Poststroke differences in IADL independence largely reflect pre stroke disparities

Using Ownership as an Incentive

Agency theory is used to develop hypotheses regarding the effects of ownership proliferation on firm performance. The authors examine the effects of chief executive officer (CEO) ownership, executive team ownership, and all employee ownership in addition to the moderating effect of risk on firm survival and stock price. Firms with low CEO ownership outperform those with high levels of CEO ownership across all levels of risk, but the effect is most pronounced for low-risk firms. Executive team ownership is negatively related to firm performance, whereas ownership for all employees is positively associated with firm performance, particularly for higher risk firms.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67316/2/10.1177_1059601199244003.pd

Multiple agency perspective, family control, and private information abuse in an emerging economy

Using a comprehensive sample of listed companies in Hong Kong this paper investigates how family control affects private information abuses and firm performance in emerging economies. We combine research on stock market microstructure with more recent studies of multiple agency perspectives and argue that family ownership and control over the board increases the risk of private information abuse. This, in turn, has a negative impact on stock market performance. Family control is associated with an incentive to distort information disclosure to minority shareholders and obtain private benefits of control. However, the multiple agency roles of controlling families may have different governance properties in terms of investors’ perceptions of private information abuse. These findings contribute to our understanding of the conflicting evidence on the governance role of family control within a multiple agency perspectiv

Altered thymic differentiation and modulation of arthritis by invariant NKT cells expressing mutant ZAP70

Various subsets of invariant natural killer T (iNKT) cells with different cytokine productions develop in the mouse thymus, but the factors driving their differentiation remain unclear. Here we show that hypomorphic alleles of Zap70 or chemical inhibition of Zap70 catalysis leads to an increase of IFN-gamma-producing iNKT cells (NKT1 cells), suggesting that NKT1 cells may require a lower TCR signal threshold. Zap70 mutant mice develop IL-17-dependent arthritis. In a mouse experimental arthritis model, NKT17 cells are increased as the disease progresses, while NKT1 numbers negatively correlates with disease severity, with this protective effect of NKT1 linked to their IFN-gamma expression. NKT1 cells are also present in the synovial fluid of arthritis patients. Our data therefore suggest that TCR signal strength during thymic differentiation may influence not only IFN-gamma production, but also the protective function of iNKT cells in arthritis

Miscarriage and stillbirth following maternal Zika virus infection in nonhuman primates.

Zika virus (ZIKV) infection is associated with congenital defects and pregnancy loss. Here, we found that 26% of nonhuman primates infected with Asian/American ZIKV in early gestation experienced fetal demise later in pregnancy despite showing few clinical signs of infection. Pregnancy loss due to asymptomatic ZIKV infection may therefore be a common but under-recognized adverse outcome related to maternal ZIKV infection

Genome-wide association studies for methane production in dairy cattle

© 2019 by the authors. Licensee MDPI, Basel, Switzerland. Genomic selection has been proposed for the mitigation of methane (CH4) emissions by cattle because there is considerable variability in CH4 emissions between individuals fed on the same diet. The genome-wide association study (GWAS) represents an important tool for the detection of candidate genes, haplotypes or single nucleotide polymorphisms (SNP) markers related to characteristics of economic interest. The present study included information for 280 cows in three dairy production systems in Mexico: 1) Dual Purpose (n = 100), 2) Specialized Tropical Dairy (n = 76), 3) Familiar Production System (n = 104). Concentrations of CH4 in a breath of individual cows at the time of milking (MEIm) were estimated through a system of infrared sensors. After quality control analyses, 21,958 SNPs were included. Associations of markers were made using a linear regression model, corrected with principal component analyses. In total, 46 SNPs were identified as significant for CH4 production. Several SNPs associated with CH4 production were found at regions previously described for quantitative trait loci of composition characteristics of meat, milk fatty acids and characteristics related to feed intake. It was concluded that the SNPs identified could be used in genomic selection programs in developing countries and combined with other datasets for global selection