537 research outputs found
Owner-Operator versus Company-Driver Safety Performance Analysis
The safety performance of motor carriers is a serious concern in the trucking industry and is a top priority for the U.S. Department of Transportation. This study explored the extent to which a carrier\u27s use of owner-operators and/or company drivers affects safety performance. Two primary research questions were addressed: how does motor carrier firm size relate to organizational flexibility, or the use of owner-operators versus company drivers, and does organizational flexibility affect safety performance? The study also examined whether safety performance varies by industry segment. A dataset based on data obtained for a previous study was created that includes equipment ownership profile information for approximately 108,780 motor carriers. An analysis of the data indicated that the larger the firm, the lower the use of company drivers; contrary to expectations, the use of company drivers results in poorer safety performance; and safety performance varies by industry segment
A Firm Size and Safety Performance Profile of the U.S. Motor Carrier Industry
The purpose of this study was the development of a driver-focused truck crash prediction model with a particular focus on the size of the carrier that the driver is associated with at the time of a state reportable crash. While previous studies have shown that the characteristics of the driver affect driver involvement in reportable crashes, scant attention has been paid to how the size of the carrier affects crash rates. Generally speaking, smaller carriers do not have the resources to invest in monitoring and implementing sound safety practices to ensure safe operations in the U.S. motor carrier industry. This represents a significant problem because the majority of carriers in the industry are small carriers. This study seeks to enhance the understanding of how the characteristics of carriers contribute to driver involvement in state reportable crashes
Solvent-induced organization: A physical model of folding myoglobin
The essential features of the in vitro refolding of myoglobin are expressed
in a solvable physical model. Alpha helices are taken as the fundamental
collective coordinates of the system, while the refolding is assumed to be
mainly driven by solvent-induced hydrophobic forces. A quantitative model of
these forces is developed and compared with experimental and theoretical
results. The model is then tested by being employed in a simulation scheme
designed to mimic solvent effects. Realistic dynamic trajectories of myoglobin
are shown as it folds from an extended conformation to a close approximation of
the native state. Various suggestive features of the process are discussed. The
tenets of the model are further tested by folding the single-chain plant
protein leghemoglobin.Comment: Rockefeller preprint RU 93-3-B 28 pages, plain LATEX Figures
available by request to [email protected]
RISK MITIGATION IN THE SUPPLY CHAIN: EXAMINING THE ROLE OF IT INVESTMENT TO MANAGE SAFETY PERFORMANCE
Safety management in the supply chain is an interesting topic. The existence of unexpected supply chain events makes supply chain decision making difficult. To improve their response to unexpected events such as natural disasters or workplace accidents, managers are beginning to examine the link between information technology (IT) and safety in the supply chain.
This dissertation examines the IT and safety link in three main ways. First, in the chapter entitled, "IT Investment and Safety: An Examination of The Impact of Information Technology on Safety Performance in a High Reliability Organization," drawing upon the work of Bharadwaj (2000), a theoretical model that links a firm's investment in IT resources to safety is developed. This model is empirically tested. A key finding is that physical IT resources, human IT resources, and growth in IT resources do contribute to safety performance.
The second way that the IT and safety link is examined is through a U.S. Department of Transportation sponsored survey. In the chapter entitled, "Technology Adoption Patterns in the U.S. Motor Carrier Industry," a national survey is conducted to examine the safety technology adoption practices of larger trucking firms. The survey consists of twenty-six leading-edge safety technologies. A key finding is that larger trucking firms and firms that travel long distances are leaders in IT investment.
Drawing on the resource-based view of the firm (RBV), the third way that the IT and safety link is examined is in the chapter entitled "Driving for Safety: An Examination of Safety Technology Adoption and Firm Safety Performance in the U.S. Motor Carrier Industry." The RBV framework describes how a firm's internal resources may be used to improve firm performance. Based on an over 50% survey response rate, a key finding is that safety technology resources do contribute to safety performance. It is also discovered that if the firm's top management team is knowledgeable about safety technology practices, the effect of safety technology resources on safety performance increases. Similarly, if the firm's IT staff has technology project management skills, the effect of safety technology resources on safety performance increases
A Structure–Conduct–Performance Perspective of How Strategic Supply Chain Integration Affects Firm Performance
There are several factors that affect a firm\u27s ability to successfully integrate internally and externally for organizational improvement. This study seeks to understand the relationship between a firm\u27s strategy, its supply chain integration efforts, and firm performance. Leveraging the theoretical lens of structure–conduct–performance from the industrial organization economics literature, and utilizing both archival and survey data, we describe how firms may align their internal and external supply chain integration strategies with customers and suppliers. In doing so, these internal and external integration strategies affect the firm\u27s ability to respond to customer demand, which then impacts operational and financial performance. Our work provides theoretical and empirical evidence of these relationships and thus extends prior strategic supply chain integration literature
Long-term efficacy of endoscopic cyclophotocoagulation in the management of glaucoma following cataract surgery in children
Purpose
To report the long-term efficacy of endoscopic cyclophotocoagulation (ECP) in pediatric glaucoma following cataract surgery (GFCS).
Methods
ECP was performed on 35 eyes of 25 patients 24 mm Hg, alternative glaucoma procedure following ECP, or occurrence of visually significant complications. Analysis was performed to estimate risk factors for failure.
Results
A total of 27 aphakic and 8 pseudophakic eyes were included. Pretreatment IOP averaged 33.9 ± 7.9 mm Hg. Final IOP after a mean follow-up period of 7.2 years was 18.9 ± 8.8 mm Hg (P < 0.001). The success rate was 54% (19/35 eyes). The failure rate was not increased in pseudophakic patients relative to aphakic patients. Patients with single ECP demonstrated preserved visual acuity from baseline to final follow-up.
Conclusions
In this patient cohort, with average follow-up period of 7.2 years, ECP was useful in the treatment of pediatric GFCS
The Role of Industry, Geography and Firm Heterogeneity in Credit Risk Diversification
In theory the potential for credit risk diversification for banks could be substantial. Portfolio diversification is driven broadly by two characteristics: the degree to which systematic risk factors are correlated with each other and the degree of dependence individual firms have to the different types of risk factors. We propose a model for exploring these dimensions of credit risk diversification: across industry sectors and across different countries or regions. We find that full firm-level parameter heterogeneity matters a great deal for capturing differences in simulated credit loss distributions. Imposing homogeneity results in overly skewed and fat-tailed loss distributions. These differences become more pronounced in the presence of systematic risk factor shocks: increased parameter heterogeneity greatly reduces shock sensitivity. Allowing for regional parameter heterogeneity seems to better approximate the loss distributions generated by the fully heterogeneous model than allowing just for industry heterogeneity. The regional model also exhibits less shock sensitivity
Phosphorylation of LXRα impacts atherosclerosis regression by modulating monocyte trafficking
LXRα activation in macrophages enhances regression of atherosclerotic plaques in mice by regulating genes crucial for cholesterol efflux, cell motility and inflammation. Diabetes, however, impairs plaque regression in mice. LXRα is phosphorylated at serine 198 (pS198), which affects the expression of genes controlling inflammation, lipid metabolism and cell movement. We hypothesize that LXRα function is affected by hyperglycemia through changes in LXRα pS198. Indeed, macrophages cultured in diabetes relevant high glucose versus normal glucose display alterations in LXR-dependent gene expression and increased LXRα pS198. We therefore examined the consequence of disrupting LXRα phosphorylation (S196A in mouse LXRα) during regression of atherosclerosis in normal and diabetic mice. We find that phosphorylation deficient LXRα S196A reduces macrophage retention in plaques in diabetes, which is predicted to be anti-atherogenic and enhance plaque regression. However, this favorable effect on regression is masked by increased monocyte infiltration in the plaque attributed to leukocytosis in LXRα S196A mice. RNA-seq of plaque macrophages from diabetic S196A mice shows increased expression of chemotaxis and decreased expression of cell adhesion genes, consistent with reduced macrophage retention by LXRα S196A. Thus, the non-phosphorylated form of LXRα precludes macrophage retention in the plaque. Our study provides the first evidence for a physiological role of LXRα phosphorylation in modulating atherosclerosis regression. Compounds that prevent LXRα phosphorylation or ligands that induce the conformation of non-phosphorylated LXRα may selectively enhance macrophage emigration from atherosclerotic plaques
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