Effect of Speed, Flow, and Geometric Characteristics on Crash Frequency for Two-Lane Highways

Author(s):  
Nicholas J. Garber ◽  
Angela A. Ehrhart

Although during the past several years significant progress has been made in improving safety on U.S. highways, the frequency and severity of crashes continue to be of concern. A better understanding of the factors associated with crashes will facilitate the identification of suitable countermeasures that could further reduce the occurrence of crashes. Results are presented from a study that determines how the characteristics of speed, flow, and geometry affect the crash rates for two-lane highways. Deterministic models that relate the crash rate with the mean speed, standard deviation of speed, flow per lane, lane width, and shoulder width are presented. The multivariate ratio of polynomials method was used to develop the models. Research was limited to two-lane roadways in Virginia with speed limits of 89 km/h (55 mph). The data were obtained from speed-monitoring stations established by the Virginia Department of Transportation and from police accident reports from January 1993 to September 1995.

Author(s):  
G.W. Maupin

Because of high air voids, long-lasting damp spots on pavement surfaces, and problems that other states have had with permeable coarse Superpave mixes, the Virginia Department of Transportation (VDOT) decided to investigate the permeability of its Superpave mixes. As part of this study, VDOT also tested other asphalt mixes. Falling-head permeability tests were performed on pavement cores to determine the general permeability of the mixes. The permeability of some of the pavement cores was compared with the permeability of specimens made in the laboratory through the use of mixtures sampled during construction to determine whether laboratory specimens could be used to predict pavement permeability. The primary purpose of this investigation was to determine the general magnitude of permeability for mixes being used by VDOT, with an emphasis on Superpave mixes. A large percentage of the field cores contained excessive voids, resulting in excessive permeability. Each mix had a unique voids-permeability relationship. Mixes that were composed of large aggregates required fewer voids to achieve an acceptable level of permeability. In four of five cases, the results of laboratory tests were generally quite successful in indicating field permeability. The preliminary permeability testing demonstrates the importance of achieving low voids in the field and will help in the future development of density specifications and possibly in the establishment of permeability requirements. It is recommended that the permeability test continue to be used to help set such limits.


1973 ◽  
Vol 12 (2) ◽  
pp. 181-188
Author(s):  
Rafiq Ahmad

Like nations and civilizations, sciences also pass through period of crises when established theories are overthrown by the unpredictable behaviour of events. Economics is passing through such a crisis. The challenge thrown by the Great Depression of early 1930s took a decade before Keynes re-established the supremacy of economics. But this supremacy has again been upset by the crisis of poverty in the vast under-developed world which attained political independence after the Second World War. Poverty had always existed but never before had it been of such concern to economists as during the past twenty five years or so. Economic literature dealing with this problem has piled up but so have the agonies of poverty. No plausible and well-integrated theory of economic development or under-development has emerged so far, though brilliant advances have been made in isolated directions.


Author(s):  
Rocco J. Rotello ◽  
Timothy D. Veenstra

: In the current omics-age of research, major developments have been made in technologies that attempt to survey the entire repertoire of genes, transcripts, proteins, and metabolites present within a cell. While genomics has led to a dramatic increase in our understanding of such things as disease morphology and how organisms respond to medications, it is critical to obtain information at the proteome level since proteins carry out most of the functions within the cell. The primary tool for obtaining proteome-wide information on proteins within the cell is mass spectrometry (MS). While it has historically been associated with the protein identification, developments over the past couple of decades have made MS a robust technology for protein quantitation as well. Identifying quantitative changes in proteomes is complicated by its dynamic nature and the inability of any technique to guarantee complete coverage of every protein within a proteome sample. Fortunately, the combined development of sample preparation and MS methods have made it capable to quantitatively compare many thousands of proteins obtained from cells and organisms.


2016 ◽  
Vol 5 (09) ◽  
pp. 4896
Author(s):  
Sripriya C.S.* ◽  
Shanthi B. ◽  
Arockia Doss S. ◽  
Antonie Raj I. ◽  
Mohana Priya

Scrub typhus (Orientia tsutsugamushi), is a strict intracellular bacterium which is reported to be a recent threat to parts of southern India. There is re-emergence of scrub typhus during the past few years in Chennai. Scrub typhus is an acute febrile illness which generally causes non-specific symptoms and signs. The clinical manifestations of this disease range from sub-clinical disease to organ failure to fatal disease. This study documents our laboratory experience in diagnosis of scrub typhus in patients with fever and suspected clinical symptoms of scrub typhus infection for a period of two years from April 2014 to April 2016 using immunochromatography and IgM ELISA methods. The study was conducted on 648 patients out of whom 188 patients were found to be positive for scrub typhus. Results also showed that pediatric (0 -12 years) and young adults (20 – 39 years) were more exposed to scrub typhus infection and female patients were more infected compared to male. The study also showed that the rate of infection was higher between September to February which also suggested that the infection rate is proportional to the climatic condition. Statistical analysis showed that the mean age of the patients in this study was 37.6, standard deviation was 18.97, CV % was 50.45. 


Author(s):  
John Hunsley ◽  
Eric J. Mash

Evidence-based assessment relies on research and theory to inform the selection of constructs to be assessed for a specific assessment purpose, the methods and measures to be used in the assessment, and the manner in which the assessment process unfolds. An evidence-based approach to clinical assessment necessitates the recognition that, even when evidence-based instruments are used, the assessment process is a decision-making task in which hypotheses must be iteratively formulated and tested. In this chapter, we review (a) the progress that has been made in developing an evidence-based approach to clinical assessment in the past decade and (b) the many challenges that lie ahead if clinical assessment is to be truly evidence-based.


2021 ◽  
pp. 088506662199232
Author(s):  
Xiaojuan Zhang ◽  
Xin Li

Septic shock with multiple organ failure is a devastating situation in clinical settings. Through the past decades, much progress has been made in the management of sepsis and its underlying pathogenesis, but a highly effective therapeutic has not been developed. Recently, macromolecules such as histones have been targeted in the treatment of sepsis. Histones primarily function as chromosomal organizers to pack DNA and regulate its transcription through epigenetic mechanisms. However, a growing body of research has shown that histone family members can also exert cellular toxicity once they relocate from the nucleus into the extracellular space. Heparin, a commonly used anti-coagulant, has been shown to possess life-saving capabilities for septic patients, but the potential interplay between heparin and extracellular histones has not been investigated. In this review, we summarize the pathogenic roles of extracellular histones and the therapeutic roles of heparin in the development and management of sepsis and septic shock.


Atmosphere ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 683
Author(s):  
Mark DeMaria ◽  
James L. Franklin ◽  
Matthew J. Onderlinde ◽  
John Kaplan

Although some recent progress has been made in operational tropical cyclone (TC) intensity forecasting, the prediction of rapid intensification (RI) remains a challenging problem. To document RI forecast progress, deterministic and probabilistic operational intensity models used by the National Hurricane Center (NHC) are briefly reviewed. Results show that none of the deterministic models had RI utility from 1991 to about 2015 due to very low probability of detection, very high false alarm ratio, or both. Some ability to forecast RI has emerged since 2015, with dynamical models being the best guidance for the Atlantic and statistical models the best RI guidance for the eastern North Pacific. The first probabilistic RI guidance became available in 2001, with several upgrades since then leading to modest skill in recent years. A tool introduced in 2018 (DTOPS) is currently the most skillful among NHC’s probabilistic RI guidance. To measure programmatic progress in forecasting RI, the Hurricane Forecast Improvement Program has introduced a new RI metric that uses the traditional mean absolute error but restricts the sample to only those cases where RI occurred in the verifying best track or was forecast. By this metric, RI forecasts have improved by ~20–25% since the 2015–2017 baseline period.


2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S441-S442
Author(s):  
Xing Tan ◽  
Andrew M Skinner ◽  
Benjamin Sirbu ◽  
Larry H Danziger ◽  
Dale N Gerding ◽  
...  

Abstract Background There is a paucity of data assessing outcomes of alternate fidaxomicin strategies in patients with recurrent Clostridioides difficile infection (rCDI). The objective of our study is to evaluate a tapered-pulsed (T-P) fidaxomicin regimen that was administered immediately following a course of CDI treatment with initial symptom resolution in patients with multiple rCDI. Methods We reviewed the characteristics and outcomes of 46 consecutive patients who received T-P fidaxomicin between January 1, 2014-June 30, 2019 in a specialty CDI clinic. The first episode in which fidaxomicin T-P was administered was analyzed. Failure was defined as the persistence of diarrhea and/or the need for additional CDI treatment at any time on T-P fidaxomicin. Sustained clinical cure (SCC) was defined as resolution of diarrhea without recurrence. Recurrence was defined as the return of diarrhea requiring retreatment with CDI therapy after completion of T-P fidaxomicin. Both SCC and recurrence were evaluated at 30 and 90 days after completion of T-P fidaxomicin. Results The mean±SD age of the 46 patients was 63.2±19.9 years, 71.7% were female, and the mean±SD CDI episodes within the past year was 3±1.4 . Most patients (73.9%) had previously failed a vancomycin tapered and/or pulsed regimen. Prior to administering T-P fidaxomicin, a treatment regimen was given to ensure resolution of symptoms. The CDI treatment most commonly used (58.7%) was vancomycin. The T-P fidaxomicin regimen used consisted of 200 mg given once daily for 7 days followed by 200 mg every other day for a median (min-max) duration of 33 (6-120) days. Two patients (4%) failed to respond to T-P fidaxomicin; 34 (74%) and 28 (61%) achieved SCC at 30 and 90 days, respectively. Among the 44 patients that successfully completed the T-P fidaxomicin regimen, recurrence developed in 10 (22.7%) and 16 (36.4%) of patients at 30 and 90 days, respectively, with a median (min-max) time to recurrence of 20 (3-87) days (Figure 1). Four patients with recurrence had received subsequent systemic antibiotics. Figure 1. Course of CDI therapy and follow-up Conclusion A tapered-pulsed fidaxomicin strategy may be effective in patients with multiply rCDI who are refractory to other treatments, including a vancomycin tapered and pulsed regimen. Disclosures Larry H. Danziger, PharmD, Merck (Speaker’s Bureau)


1971 ◽  
Vol 16 (3) ◽  
pp. 173-182 ◽  
Author(s):  
Gavin Shaw ◽  
Bernard Groden ◽  
Evelyn Hastings

The establishment, staffing and structure and observations made in the first year of the existence of coronary care in an intensive care unit in a general hospital are recorded. Two hundred and twenty eight patients were admitted during the year in whom the diagnosis of myocardial infarction was confirmed. There were 29 deaths in the unit and 14 deaths occurred in the wards of the hospital after discharge from the unit. 49.1 per cent of the patients were admitted within 4 hours of the onset of symptoms and the mean duration of stay in the unit was 86.5 hours. The type of arrhythmia detected in the unit, and the treatment given to the patients both before and after admission to the intensive care unit are described.


Hand Surgery ◽  
2004 ◽  
Vol 09 (01) ◽  
pp. 19-27 ◽  
Author(s):  
J. A. Casaletto ◽  
V. Rajaratnam

Surgical process re-engineering is a methodology where the entire surgical process is systematically analysed and re-designed. The process starts with mapping of the current process followed by in-depth analysis of the existing process. A new process is drafted with the aim of making the whole procedure more efficient. The new process is then discussed with all the staff involved in the operating room. Following implementation of the process, surgical process re-engineering should ideally be routinely carried out to continuously improve the procedure. We present an example of surgical process re-engineering which we carried out on the procedure of carpal tunnel release. We used carpal tunnel release as a model as it is a very common operation, with predictable intra-operative findings, and the patient is likely to benefit directly from procedure time reduction. A preliminary mapping of three procedures was done followed by a detailed timed mapping of five routine carpal tunnel decompression procedures. The mapped process was analysed in detail and a number of changes were made in the process. After implementing the new process, a further five procedures were mapped and timed again. In comparison to the original process, we achieved a reduction of 20% in the mean procedure time and a reduction of 42% in the number of steps from 66 to 37.


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