595 research outputs found
Effects of Subsurface Drainage on Pavement Performance
This report evaluates the effects of subsurface drainage features on pavement performance through a program of inspection and testing of the subsurface drainage features present in the Long-Term Pavement Performance (LTPP) SPS-1 and SPS-2 field sections. The report will be of particular interest to engineers in the public and private sectors with responsibility for the design, construction, and rehabilitation of highway pavements
Molecular principles underlying dual RNA specificity in the Drosophila SNF protein
The first RNA recognition motif of the Drosophila SNF protein is an example of an RNA binding protein with multi-specificity. It binds different RNA hairpin loops in spliceosomal U1 or U2 small nuclear RNAs, and only in the latter case requires the auxiliary U2A′ protein. Here we investigate its functions by crystal structures of SNF alone and bound to U1 stem-loop II, U2A′ or U2 stem-loop IV and U2A′, SNF dynamics from NMR spectroscopy, and structure-guided mutagenesis in binding studies. We find that different loop-closing base pairs and a nucleotide exchange at the tips of the loops contribute to differential SNF affinity for the RNAs. U2A′ immobilizes SNF and RNA residues to restore U2 stem-loop IV binding affinity, while U1 stem-loop II binding does not require such adjustments. Our findings show how U2A′ can modulate RNA specificity of SNF without changing SNF conformation or relying on direct RNA contacts
Intrinsic flexibility of snRNA hairpin loops facilitates protein binding
Stem–loop II of U1 snRNA and Stem–loop IV of U2 snRNA typically have 10 or 11 nucleotides in their loops. The fluorescent nucleobase 2-aminopurine was used as a substitute for the adenines in each loop to probe the local and global structures and dynamics of these unusually long loops. Using steady-state and time-resolved fluorescence, we find that, while the bases in the loops are stacked, they are able to undergo significant local motion on the picosecond/nanosecond timescale. In addition, the loops have a global conformational change at low temperatures that occurs on the microsecond timescale, as determined using laser T-jump experiments. Nucleobase and loop motions are present at temperatures far below the melting temperature of the hairpin stem, which may facilitate the conformational change required for specific protein binding to these RNA loops
Structural Overlay Strategies for Jointed Concrete Pavements. Volume IV: Guidelines for the Selection of Rehabilitation Alternatives
DTFH61-86-C-00079A major field study and evaluation has been conducted into the effectiveness of three structural overlay types for portland cement concrete (PCC) pavements. These include sawing and sealing asphalt concrete (AC) overlays of PCC pavements, cracking and seating PCC pavements prior to AC overlay, and constructing a thin bonded PCC overlay on top of the existing PCC pavement. Condition surveys, deflection testing, and roughness measurements were performed on a total of 55 sections. The performance of these sections was evaluated and the effectiveness of each overlay type analyzed. Based on the field data, guidelines were developed for the use of these structural overlays. This volume provides detailed guidelines and case studies prepared specifically for the practicing engineer as an aid in the evaluation and rehabilitation of jointed concrete pavements. Feasibility guidelines are given for restoration, resurfacing, and reconstruction alternatives in terms of constructability, future life and life-cycle costs. New prediction models are developed for bonded PCC overlays, sawing and sealing and AC overlay, and cracking and seating and AC overlay. The EXPEAR program was extensively modified to include the above rehabilitation alternatives and improved predictive models and to provide for much easier usage by the practicing engineer for evaluation and rehabilitation. Detailed rehabilitation case studies are presented that will be of interest to the practicing engineer
Structural Overlay Strategies for Jointed Concrete Pavements. Volume VI: Appendix A, User's Manual for the EXPEAR Computer Program
DTFH61-86-C-00079A major field study and evaluation has been conducted into the effectiveness of three structural overlay types for portland cement concrete (PCC) pavements. These include sawing and sealing asphalt concrete (AC) overlays of PCC pavements, cracking and seating PCC pavements prior to AC overlay, and constructing a thin bonded PCC overlay on top of the existing PCC pavement. Condition surveys, deflection testing, and roughness measurements were performed on a total of 55 sections. The performance of these sections was evaluated and the effectiveness of each overlay type analyzed. Based on the field data, guidelines were developed for the use of structural overlays. This volume provides a users guide to the EXPEAR computerized system to assist practicing engineers in evaluating concrete highway pavements, in developing feasible rehabilitation alternatives, and in predicting the performance and cost-effectiveness of the alternatives. EXPEAR is intended for use by State highway engineers in project-level rehabilitation planning and design for conventional concrete pavements (JRCP, JPCP, and CRCP). EXPEAR uses information about the pavement to guide the engineer through evaluation of a pavement's present condition and development of one or more feasible rehabilitation strategies. A computer program has been developed for each of the three pavement types addressed. The EXPEAR version 1.4 program operates on any IBM-compatible personal computer. Extensive revisions were made in EXPEAR 1.4 to improve the user-friendliness of the program and its capabilities
New trends in the treatment of bone metastasis
Bone metastasis is often the penultimate harbinger of death for many cancer patients. Bone metastases are often associated with fractures and severe pain resulting in decreased quality of life. Accordingly, effective therapies to inhibit the development or progression of bone metastases will have important clinical benefits. To achieve this goal understanding the mechanisms through which bone metastases develop and progress may provide targets to inhibit the metastases. In the past few years, there have been advances in both understanding the mechanisms through which bone metastases develop and how they impact bone remodeling. Additionally, gains in promising clinical strategies to target bone metastases have been developed. In this prospectus, we will discuss some of these advances. J. Cell. Biochem. 102: 1095–1102, 2007. © 2007 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/57363/1/21540_ftp.pd
Workplace Turbulence and Workforce Preparedness
The year 1973 marked a divide in the postwar economy.1 During the 25 years between 1948 and 1973, private sector productivity increased at an annual rate of 2.9%. Productivity improvement after 1973 fell way below this long-term trend, leveling off at about 0.6% a year until 1981 and rising to only 1.6% a year between 1981 and 1987. A similar pattern is reflected in the real wages of the workforce.2The conventional interpretation of this difference in the U.S. economy before and after 1973 is that it reflects the combined influence of the OPEC oil shock and the influx into the labor market of inexperienced workers born in the postwar baby boom, possibly reinforced by growth in regulatory costs.3 However, when the productivity data are analyzed in a growth accounting framework, these economic factors can only account for about two thirds of the productivity decline.4 What then explains the balance of the shortfall in productivity? Many analysts have pointed to the intangible effects on managers of increased economic uncertainty since 1973—growing business cautiousness, increased emphasis on short-term financial objectives, and inadequate entrepreneurial incentives.5 But economic change and uncertainty can also affect productivity through their impact on jobs and workers
Hospital Costs Related to Early Extubation after Infant Cardiac Surgery
Background
The Pediatric Heart Network Collaborative Learning Study (PHN CLS) increased early extubation rates after infant Tetralogy of Fallot (TOF) and coarctation (CoA) repair across participating sites by implementing a clinical practice guideline (CPG). The impact of the CPG on hospital costs has not been studied.
Methods
PHN CLS clinical data were linked to cost data from Children’s Hospital Association by matching on indirect identifiers. Hospital costs were evaluated across active and control sites in the pre- and post-CPG periods using generalized linear mixed effects models. A difference-in-difference approach was used to assess whether changes in cost observed in active sites were beyond secular trends in control sites.
Results
Data were successfully linked on 410/428 (96%) of eligible patients from 4 active and 4 control sites. Mean adjusted cost/case for TOF repair was significantly reduced in the post-CPG period at active sites (56,304, p<0.01) and unchanged at control sites (46,476, p=0.91), with an overall cost reduction of 27% in active vs. control sites (p=0.03). Specific categories of cost reduced in the TOF cohort included clinical (-66%, p<0.01), pharmacy (-46%, p=0.04), lab (-44%, p<0.01), and imaging (-32%, p<0.01). There was no change in costs for CoA repair at active or control sites.
Conclusions
The early extubation CPG was associated with a reduction in hospital costs for infants undergoing repair of TOF, but not CoA repair. This CPG represents an opportunity to both optimize clinical outcome and reduce costs for certain infant cardiac surgeries
Evaluation of Serodiagnostic Assays for Mycobacterium bovis
In 2011, the United States Department of Agriculture conducted a project in which elk (Cervus elaphus spp.), white-tailed deer (WTD) (Odocoileus virginianus), and reindeer (Rangifer tarandus) were evaluated by the single cervical tuberculin test (SCT), comparative cervical tuberculin test (CCT), and serologic tests. The rapid antibody detection tests evaluated were the CervidTB Stat-Pak (Stat-Pak), and the Dual Path Platform VetTB (DPP). Blood was collected from presumably uninfected animals prior to tuberculin injection for the SCT. A total of 1,783 animals were enrolled in the project. Of these, 1,752 (98.3%) were classified as presumably uninfected, based on originating from a captive cervid herd with no history of exposure to TB. Stat-Pak specificity estimates were 92.4% in reindeer, 96.7% in WTD, and 98.3% in elk and were not significantly different from SCT specificity estimates. Using the DPP in series on Stat-Pak antibody-positive samples improved specificity in the three species. Thirty one animals were classified as confirmed infected, based on necropsy and laboratory results, and 27/31 were antibody positive on Stat-Pak for an estimated sensitivity of 87.1%. The study findings indicate that rapid serologic tests used in series are comparable to the SCT and CCT and may have a greater ability to detect TB-infected cervids
Rehabilitation of Concrete Pavements, Volume III: Concrete Pavement Evaluation and Rehabilitation System
DTFH61-85-C-00004Extensive field, laboratory and analytical studies were conducted into the evaluation and rehabilitation of concrete pavements. Field studies included over 350 rehabilitated pavement sections throughout the U.S., and the construction of two field experiments. A laboratory study was conducted on anchoring dowels in full-depth repairs. Analyses of field and laboratory data identified performance characteristics, improved design and construction procedures, and provided deterioration models for rehabilitated pavements. A concrete pavement advisory system was developed to assist engineers in project level evaluation and rehabilitation. The repair techniques in Volume I include full-depth repair, partial-depth repair, load transfer restoration, edge support and diamond grinding. Overlay techniques in Volume II include bonded concrete, unbonded concrete and crack and seat with an asphalt concrete overlay. This volume, Volume III, presents a comprehensive concrete pavement evaluation and rehabilitation advisory system for jointed plain, jointed reinforced and continuously reinforced concrete pavements. Volume IV contains a description of the data collection procedures, original pavement and rehabilitation design factors, extent of the database, description of database variables, and documentation of the laboratory dowel anchoring experiment
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