239 research outputs found

    Study on Buyback Contract in Supply Chain With a Loss-Averse Supplier and Multiple Loss-Averse Retailers Under Stockout Loss Situation

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    According to the prospect theory and the loss-aversion function, this paper developers the buyback contract model in a two-stage supply chain with a loss-averse supplier and multiple loss-averse retailers. Under the stockout loss setting, we analyze the effect of the loss aversion on the behavior from the retailers and the supplier, and then the buyback contract has been shown to be able to coordinate the supply chain. Furthermore, the number of retailers and loss aversion coefficient meet a certain range, there will be a unique optimal buyback price to achieve supply chain coordination

    Mathematical Modeling of the Separation Process of Chromatography and Estimation of Parameters

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    Chromatography is widely used as a technology for separating mixtures of compounds by partitioning into the mobile and stationary phases. A mathematical model is essential not only for predicting the retention time and the peak shape of the chromatography analyte concentration distribution, but also for understanding the separation mechanism of chromatography and detecting whether the conditions were correct (e.g., whether there was an overload of the sample). A variety of statistical distribution functions such as exponential, Gaussian (normal), exponential modified Gaussian, Weibull, log-normal have been used to approximate the chromatography analyte concentration distributions, and were further applied to the deconvolution of stacked peaks. The dissertation consists of five chapters. The first chapter presents an overall introduction of the current prevailing mathematical models of chromatography analyte concentration distributions, the generalized chromatography theorem derived from chromatography table and its proof, the relation between on-chromatography analyte concentration distributions and out flow analyte concentration distributions, the asymptotic distribution of on-chromatography analyte concentration distributions and out flow analyte concentration distributions and their applications. The second chapter presents the mathematical model for the separation process of chromatography. In this chapter the first generalized theorem for modeling almost all types of chromatography was developed, and was found to match the mathematical formulas for well-known discrete distribution functions. These empirical formulas were rigorously proven by mathematical induction based on chromatography principle and chromatography process assumptions. The outflow chromatography analyte concentration distributions are demonstrated by simulation to be better approximated by the mathematical model that matches the negative binomial distribution function versus using a Gaussian distribution function, which currently is widely used for approximation. The third chapter establishes the mathematic bridge between on-chromatography and outflow analyte concentration distributions. In following with the previous chapter, which found the on chromatography and outflow analyte concentrations distributions to mathematically match the binomial and negative binomial distributions, respectively, this mathematical bridge can apply to relate these statistical distributions given they mathematical formulas are the same. This theorem is rigorously proved by mathematical induction. This relation is also demonstrated by 3D-plot of on-chromatography and outflow analyte concentration distributions for the first several stages. The fourth chapter proposed the transformation of data collected by chromatography (i.e., the analyte concentration distributions from chromatography experiments) into data that can be used for estimation to the approximate the underlying parameters that govern a particular chromatography process. Outflow chromatography analyte concentration distribution from original data were used to demonstrate this process and to compare the approach derived in this work using parameter estimated by method of moment (MOM) to the currently approach based on the Gaussian statistical distribution’s formula The fifth chapter is the summary of my dissertation work

    Enhanced temperature sensing by multi-mode coupling in an on-chip microcavity system

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    The micro-cavity is a promising sensor platform, any perturbation would disturb its linewidth, cause resonance shift or splitting. However, such sensing resolution is limited by the cavity's optical quality factor and mode volume. Here we propose and demonstrate in an on-chip integrated microcavity system that resolution of a self referenced sensor could be enhanced with multi mode coupling

    Immunosuppressants for the prophylaxis of corneal graft rejection after penetrating keratoplasty.

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    BACKGROUND: Penetrating keratoplasty is a corneal transplantation procedure in which a full-thickness cornea from the host is replaced by a graft from a donor. The use of various immunosuppressants to prevent graft rejection, the most common cause of graft failure in the late postoperative period, is increasing. OBJECTIVES: To assess the effectiveness of immunosuppressants in the prophylaxis of corneal allograft rejection after high- and normal-risk keratoplasty. SEARCH METHODS: We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (2015, Issue 4), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to May 2015), EMBASE (January 1980 to May 2015), China National Knowledge Infrastructure (CNKI) (January 1913 to February 2015), VIP database (January 1989 to February 2015), Wanfang Data (www.wanfangdata.com) (January 1990 to February 2015), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov), and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the English language databases on 18 May 2015 and the Chinese language databases on 20 February 2015. SELECTION CRITERIA: We included all randomised controlled trials (RCTs) assessing the use of immunosuppressants in the prevention of graft rejection, irrespective of publication language. DATA COLLECTION AND ANALYSIS: We used standard procedures expected by Cochrane. The primary outcome was clear graft survival at 12 months after penetrating keratoplasty. Secondary outcomes included graft rejection, best-corrected visual acuity, and quality of life. We defined 'high-risk keratoplasty' as repeat keratoplasty and other indications of reduced graft survival. MAIN RESULTS: We included six studies conducted in Germany (three studies), Iran, India, and China. Three studies were conducted in people undergoing high-risk keratoplasty and investigated three different comparisons: systemic mycophenolate mofetil (MMF) versus no MMF; systemic MMF versus systemic cyclosporine A (CsA); and topical CsA versus placebo. One study compared topical tacrolimus to topical steroid in people with normal-risk keratoplasty, and two studies compared topical CsA to placebo in people experiencing graft rejection after normal-risk keratoplasty. Overall, we considered the trials to be at unclear or high risk of bias.MMF may not improve clear graft survival (risk ratio (RR) 1.06, 95% confidence interval (CI) 0.84 to 1.33, 1 RCT, 87 participants, low-quality evidence) but may reduce the risk of graft rejection (RR 0.49, 95% CI 0.22 to 1.08, 1 RCT, 87 participants, low-quality evidence) compared to no MMF. Visual acuity was not reported.In 1 study of 52 people comparing systemic MMF and systemic CsA, there were no graft failures in the first year of follow-up. Data from the longest follow-up (three years) suggest that there may be little difference in the effect of these two treatments on clear graft survival (RR 1.10, 95% CI 0.90 to 1.35, low-quality evidence). There was low-quality evidence of an increased risk of graft rejection with systemic MMF compared to systemic CsA, but with wide CIs compatible with increased risk with systemic CsA (RR 1.48, 95% CI 0.56 to 3.93, low-quality evidence). Visual acuity was not reported.One study of 84 people comparing topical CsA to placebo did not report clear graft survival at 1 year, which suggests that all grafts survived to 1 year. This study suggests that the use of topical CsA probably leads to little or no difference in graft rejection (RR 1.00, 95% CI 0.39 to 2.58, moderate-quality evidence). At one year, the mean difference (MD) between the two groups in visual acuity was 0.07 (95% CI -0.01 to 0.15, moderate-quality evidence).Topical CsA probably does not have an effect on clear graft survival in people experiencing graft rejection after normal-risk keratoplasty compared to placebo (RR 1.03, 95% CI 0.96 to 1.10, 2 RCTs, 283 participants, moderate-quality evidence). There were inconsistent findings on graft rejection, with one study reporting a reduced incidence of graft rejection in the CsA group (RR 0.35, 95% CI 0.14 to 0.87, 230 participants) but the other study reporting a higher average number of episodes of graft rejection in people treated with CsA (MD 1.30, 95% CI 0.39 to 2.21, 43 participants). Overall, we judged this to be low-quality evidence due to risk of bias and inconsistency. There was no evidence for a difference in visual acuity between the 2 groups at final follow-up (approximately 18 months, range 2 to 33 months) (MD 0.04, 95% CI -0.10 to 0.18, 1 RCT, 43 participants, low-quality evidence).In 1 study comparing topical tacrolimus to topical steroid, the graft survived in all of the 12 treated participants and 20 control participants at 6 months. Graft rejection was rare (0 out of 12 versus 2 out of 20) (RR 0.32, 95% CI 0.02 to 6.21, low-quality evidence). Visual acuity was not reported.None of the studies reported on quality of life. We identified an unpublished trial of basiliximab (Simulect) (NCT00409656), probably completed in 2005. AUTHORS' CONCLUSIONS: Current evidence on the effect of immunosuppressants in the prevention of graft failure and rejection after high- and normal-risk keratoplasty is largely low quality because the number of trials was limited, and, in general, the trials were small and at risk of bias. Future trials should be large enough to detect important clinical effects, conducted with a view to minimising the risk of bias, and they should measure outcomes important to patients

    A Parametric Study of Oxygen Ion Cyclotron Harmonic Wave Excitation and Polarization by an Oxygen Ring Distribution

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    Oxygen ion cyclotron harmonic (OCH) waves are electromagnetic emissions with frequencies near the harmonics of the oxygen ion cyclotron frequency. They are ubiquitously observed in the Earth’s magnetosphere. These waves can be excited by an energetic O+ ring distribution. Here, we perform a parametric study of OCH waves by an O+ ring distribution. We investigate the effects of ring concentration (ηho), velocity (vr), temperature (Tr), total O+ concentration (ηo), and wave normal angles (WNAs) on the wave growth rate and polarization. We find that four-wave modes are related to OCH waves. The growth rates and frequency range increase with ηho and ηo and decrease with Tr. The peak growth rate roughly follows the first peak of Jn2 (square of the Bessel function corresponding to the O+ ring) or cold plasma wave modes, which can be used to explain the vr and WNA dependences. OCH waves shift from the transverse mode to the compressional mode as vr increases. This work used TACC to perform particle-in-cell (PIC) simulation (part of Figure 1 of this work) and was published in Journal of Geophysical Research-Space Physics.Texas Advanced Computing Center (TACC

    Core Point Pixel-Level Localization by Fingerprint Features in Spatial Domain

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    Singular point detection is a primary step in fingerprint recognition, especially for fingerprint alignment and classification. But in present there are still some problems and challenges such as more false-positive singular points or inaccurate reference point localization. This paper proposes an accurate core point localization method based on spatial domain features of fingerprint images from a completely different viewpoint to improve the fingerprint core point displacement problem of singular point detection. The method first defines new fingerprint features, called furcation and confluence, to represent specific ridge/valley distribution in a core point area, and uses them to extract the innermost Curve of ridges. The summit of this Curve is regarded as the localization result. Furthermore, an approach for removing false Furcation and Confluence based on their correlations is developed to enhance the method robustness. Experimental results show that the proposed method achieves satisfactory core localization accuracy in a large number of samples

    Magnetopause Reconnection as Influenced by the Dipole Tilt Under Southward IMF Conditions: Hybrid Simulation and MMS Observation

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    Using a three‐dimensional (3‐D) global‐scale hybrid code, the Magnetospheric Multiscale (MMS) reconnection event around 02:13 UT on 18 November 2015, highlighted in the Geospace Environment Modeling (GEM) Dayside Kinetic Challenge, is simulated, in which the interplanetary magnetic field (IMF) points southward and the geomagnetic field has a −27° dipole tilt angle. Strong southward plasma jets are found near the magnetopause as a result of the dayside reconnection. Our results indicate that the subsolar magnetopause reconnection X line shifts from the subsolar point toward the Northern Hemisphere due to the effect of the tilted geomagnetic dipole angle, consistent with the MMS observation. Subsequently, the reconnection X lines or sites and reconnection flux ropes above the equator propagate northward along the magnetopause. The formation and global distribution of the X lines and the structure of the magnetopause reconnection are investigated in detail with the simulation. Mirror mode waves are also found in the middle of the magnetosheath downstream of the quasi‐perpendicular shock where the plasma properties are consistent with the mirror instability condition. As a special outcome of the GEM challenge event, the spatial and temporal variations in reconnection, the electromagnetic power spectra, and the associated D‐shaped ion velocity distributions in the simulated reconnection event are compared with the MMS observation.Key PointsSubsolar magnetopause X lines shift toward the Northern Hemisphere due to the effect of the negative tilted geomagnetic dipole angleThe hybrid simulation magnetic fields and plasma date match MMS3 observations well during the magnetopause crossingMirror mode waves appear in the middle of the magnetosheath downstream of the quasi‐perpendicular shockPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/162687/2/jgra55909_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162687/1/jgra55909.pd

    Genome-wide analysis emancipates genomic diversity and signature of selection in Altay white-headed cattle of Xinjiang, China

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    Altay white-headed cattle have not received enough attention for several reasons. Due to irrational breeding and selection practices, the number of pure Altay white-headed cattle has decreased significantly and the breed is now on the eve of extinction. The genomic characterization will be a crucial step towards understanding the genetic basis of productivity and adaptability to survival under native Chinese agropastoral systems; nevertheless, no attempt has been made in Altay white-headed cattle. In the current study, we compared the genomes of 20 Altay white-headed cattle to the genomes of 144 individuals in representative breeds. Population genetic diversity revealed that the nucleotide diversity of Altay white-headed cattle was less than that of indicine breeds and comparable to that of Chinese taurus cattle. Using population structure analysis, we also found that Altay white-headed cattle carried the ancestry of the European and East Asian cattle lineage. In addition, we used three different methods (FST, Ξπ ratio and XP-EHH) to investigate the adaptability and white-headed phenotype of Altay white-headed cattle and compared it with Bohai black cattle. We found EPB41L5, SCG5 and KIT genes on the list of the top one percent genes, these genes might have an association with environmental adaptability and the white-headed phenotype for this breed. Our research reveals the distinctive genomic features of Altay white-headed cattle at the genome-wide level
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