1,931 research outputs found

    Ownership and financing of infrastructure : historical perspective

    Get PDF
    The authors summarize the rich and varied experiences of private and public provision of urban services in France, Great Britain, and the United States over the past 100 years. Their main focus is on experiences in the United States and on shifts back and forth between the public and private sectors. A few of their observations: (i) The values of politically important actors as well as the working of government, political, and legal institutions have shaped decisions about infrastructure development, the sorts of public goods demanded, and the roles played by private firms. (ii) The range of choices that has historically been made with respect to the ownership, financing, and operation of different infrastructures has been far too varied to be encompassed by simple distinctions between"public"and"private."(iii) Throughout the world, many infrastructures owned and operated by governments have been built by private firms. (iv) In the United States, private firms and property-owners associations of various sorts have owned outright both toll roads and residential streets. Private firms have also collected solid wastes and provided urban transport under a range of franchise, contracting, and regulatory arrangements. The situation with mass transit has been similar in Great Britain. Although water works facilities in France are predominantly government-owned, private firms operate and manage most systems under an array of contracting and leasing arrangements. (v) Even when facilities have been owned by private firms, direct competition has been of limited importance in the provision of many kinds of infrastructure. But market discipline can arise from other sources. (vi) Privatization can get government bureaucracies out of the business of performing entrepreneurial activities for which they may be poorly suited. When market forces are weak, however, and important public interests are at stake, strengthening government institutions may be a prerequisite for successful privatization. (vii) In the electric utility industry, private firms played a far greater role in U.S. electric utilities than in Great Britain, in part because of different views about appropriate roles for government in providing essential services. For similar reasons, the state played a much larger role in furnishing telecommunications services in France than in the United States. (viii) Beliefs about the"publicness"of different goods and services have helped shape the character of regulatory franchise, and contracting arrangements. When a good is seen as mainly private, it is easier for private service providers to be compensated mainly by user fees and for most decisions about price, output, and quality, no matter what the role played by private firms in actually providing services. (ix) Goods defined as"public"have often been provided free to users, even though it would have been easy to exclude nonpayers. Examples in the United States include interstate highway systems, public parks, public libraries, and police and fire protection. Free services have been provided because it is believed that in these domains market relationships should not apply - and that denying nonpayers the public services would be a denial of rights. (x) In Great Britain and the United States, the contracting out of public services has been both supported and opposed because of its potential to break the power of public sector unions and to cut workers'pay. In the United States, privatization has also come under attack on the grounds that opportunities for minority employment may be reduced.Regional Governance,Public Sector Economics&Finance,Decentralization,Public Sector Management and Reform,Urban Governance and Management,Public Sector Management and Reform,Urban Governance and Management,Regional Governance,Town Water Supply and Sanitation,Public Sector Economics&Finance

    The Role of fast magnetosonic waves in the release and conversion via reconnection of energy stored by a current sheet

    Full text link
    Using a simple two-dimensional, zero-beta model, we explore the manner by which reconnection at a current sheet releases and dissipates free magnetic energy. We find that only a small fraction (3%-11% depending on current sheet size) of the energy is stored close enough to the current sheet to be dissipated abruptly by the reconnection process. The remaining energy, stored in the larger-scale field, is converted to kinetic energy in a fast magnetosonic disturbance propagating away from the reconnection site, carrying the initial current and generating reconnection-associated flows (inflow and outflow). Some of this reflects from the lower boundary (the photosphere) and refracts back to the X-point reconnection site. Most of this inward wave energy is reflected back again, and continues to bounce between X-point and photosphere until it is gradually dissipated, over many transits. This phase of the energy dissipation process is thus global and lasts far longer than the initial purely local phase. In the process a significant fraction of the energy (25%-60%) remains as undissipated fast magnetosonic waves propagating away from the reconnection site, primarily upward. This flare-generated wave is initiated by unbalanced Lorentz forces in the reconnection-disrupted current sheet, rather than by dissipation-generated pressure, as some previous models have assumed. Depending on the orientation of the initial current sheet the wave front is either a rarefaction, with backward directed flow, or a compression, with forward directed flow

    Workers\u27 Compensation

    Get PDF

    The Virtual Check Ride (VCR) as a Diagnostic and Remediation System

    Get PDF
    The Florida Department of Transportation (FDOT) and the U.S. Department of Transportation (US DOT) have identified safety and operator performance as major objectives in addressing the inter-modal transportation needs of the state and nation. The Florida Department of Highway Safety and Motor Vehicles is working diligently to address the issue of safety on Florida’s roads by developing and enforcing standards and certification of Commercial Driver License (CDL) training and issuance, as well as continual monitoring via enforcement. The Florida Trucking Association (FTA), representing the commercial industry side of the community, is likewise very concerned and is also taking steps to deal with these challenges. Clearly the issue of safety and the proper training of persons who will be operating heavy trucks is of great concern to all of us in the community. Driver training, safety, security, performance enhancements and accident reduction are priority issues in the truck driving industry. With this emphasis, and the increase in highway safety compromised by fraudulent or unskilled CDL licensed drivers, the new Virtual Check Ride, a simulated knowledge and skilled-based diagnostic system for professional truck drivers, was created using multimedia blended simulation that includes computerbased training (CBT) elements. This system also utilizes the GE VS TruckDriving Simulator. While the implications of VCR are rich with possibilities, the goal of this research is to validate and verify the newest version of the VCR system within the trucking community (e.g., Frito Lay and others)

    Impact of neonatal intensive care bed configuration on rates of late-onset bacterial sepsis and methicillin-resistant Staphylococcus aureus colonization

    Get PDF
    OBJECTIVES: Infections cause significant morbidity and mortality in neonatal intensive care units (NICUs). The association between nursery design and nosocomial infections has not been delineated. We hypothesized that rates of colonization by methicillin-resistant Staphylococcus aureus (MRSA), late-onset sepsis, and mortality are reduced in single-patient rooms. DESIGN: Retrospective cohort study. SETTING: NICU in a tertiary referral center. METHODS: Our NICU is organized into single-patient and open-unit rooms. Clinical datasets including bed location and microbiology results were examined over a 29-month period. Differences in outcomes between bed configurations were determined by Chi-square and Cox regression. PATIENTS: All NICU patients. RESULTS: Among 1823 patients representing 55,166 patient-days, single-patient and open-unit models had similar incidences of MRSA colonization and MRSA colonization-free survival times. Average daily census was associated with MRSA colonization rates only in single-patient rooms (hazard ratio 1.31, p=0.039), while hand hygiene compliance on room entry and exit was associated with lower colonization rates independent of bed configuration (hazard ratios 0.834 and 0.719 per 1% higher compliance, respectively). Late-onset sepsis rates were similar in single-patient and open-unit models as were sepsis-free survival and the combined outcome of sepsis or death. After controlling for demographic, clinical and unit-based variables, multivariate Cox regression demonstrated that bed configuration had no effect on MRSA colonization, late-onset sepsis, or mortality. CONCLUSIONS: MRSA colonization rate was impacted by hand hygiene compliance, regardless of room configuration, while average daily census only affected infants in single-patient rooms. Single-patient rooms did not reduce the rates of MRSA colonization, late-onset sepsis or death

    TIR-NBS-LRR genes are rare in monocots: evidence from diverse monocot orders

    Get PDF
    Background: Plant resistance (R) gene products recognize pathogen effector molecules. Many R genes code for proteins containing nucleotide binding site (NBS) and C-terminal leucine-rich repeat (LRR) domains. NBS-LRR proteins can be divided into two groups, TIR-NBS-LRR and non-TIR-NBS-LRR, based on the structure of the N-terminal domain. Although both classes are clearly present in gymnosperms and eudicots, only non-TIR sequences have been found consistently in monocots. Since most studies in monocots have been limited to agriculturally important grasses, it is difficult to draw conclusions. The purpose of our study was to look for evidence of these sequences in additional monocot orders. Findings: Using degenerate PCR, we amplified NBS sequences from four monocot species (C. blanda, D. marginata, S. trifasciata, and Spathiphyllum sp.), a gymnosperm (C. revoluta) and a eudicot (C. canephora). We successfully amplified TIR-NBS-LRR sequences from dicot and gymnosperm DNA, but not from monocot DNA. Using databases, we obtained NBS sequences from additional monocots, magnoliids and basal angiosperms. TIR-type sequences were not present in monocot or magnoliid sequences, but were present in the basal angiosperms. Phylogenetic analysis supported a single TIR clade and multiple non-TIR clades. Conclusion: We were unable to find monocot TIR-NBS-LRR sequences by PCR amplification or database searches. In contrast to previous studies, our results represent five monocot orders (Poales, Zingiberales, Arecales, Asparagales, and Alismatales). Our results establish the presence of TIR-NBS-LRR sequences in basal angiosperms and suggest that although these sequences were present in early land plants, they have been reduced significantly in monocots and magnoliids

    TIR-NBS-LRR genes are rare in monocots: evidence from diverse monocot orders

    Get PDF
    Background: Plant resistance (R) gene products recognize pathogen effector molecules. Many R genes code for proteins containing nucleotide binding site (NBS) and C-terminal leucine-rich repeat (LRR) domains. NBS-LRR proteins can be divided into two groups, TIR-NBS-LRR and non-TIR-NBS-LRR, based on the structure of the N-terminal domain. Although both classes are clearly present in gymnosperms and eudicots, only non-TIR sequences have been found consistently in monocots. Since most studies in monocots have been limited to agriculturally important grasses, it is difficult to draw conclusions. The purpose of our study was to look for evidence of these sequences in additional monocot orders. Findings: Using degenerate PCR, we amplified NBS sequences from four monocot species (C. blanda, D. marginata, S. trifasciata, and Spathiphyllum sp.), a gymnosperm (C. revoluta) and a eudicot (C. canephora). We successfully amplified TIR-NBS-LRR sequences from dicot and gymnosperm DNA, but not from monocot DNA. Using databases, we obtained NBS sequences from additional monocots, magnoliids and basal angiosperms. TIR-type sequences were not present in monocot or magnoliid sequences, but were present in the basal angiosperms. Phylogenetic analysis supported a single TIR clade and multiple non-TIR clades. Conclusion: We were unable to find monocot TIR-NBS-LRR sequences by PCR amplification or database searches. In contrast to previous studies, our results represent five monocot orders (Poales, Zingiberales, Arecales, Asparagales, and Alismatales). Our results establish the presence of TIR-NBS-LRR sequences in basal angiosperms and suggest that although these sequences were present in early land plants, they have been reduced significantly in monocots and magnoliids

    J Regularization Improves Imbalanced Multiclass Segmentation

    Get PDF
    We propose a new loss formulation to further advance the multiclass segmentation of cluttered cells under weakly supervised conditions. When adding a Youden's J statistic regularization term to the cross entropy loss we improve the separation of touching and immediate cells, obtaining sharp segmentation boundaries with high adequacy. This regularization intrinsically supports class imbalance thus eliminating the necessity of explicitly using weights to balance training. Simulations demonstrate this capability and show how the regularization leads to correct results by helping advancing the optimization when cross entropy stagnates. We build upon our previous work on multiclass segmentation by adding yet another training class representing gaps between adjacent cells. This addition helps the classifier identify narrow gaps as background and no longer as touching regions. We present results of our methods for 2D and 3D images, from bright field images to confocal stacks containing different types of cells, and we show that they accurately segment individual cells after training with a limited number of images, some of which are poorly annotated
    • …
    corecore