bluuebunny/crossref_metadata_2025 huggingface dataset:
Temporal Expansion of a Transportation Network—II
Authors: Frey Sherwood C. , Nemhauser George L.
Published: October 2008

The problem of optimal timing of investments in the capacity of transportation networks that was developed in Part I has been extended, under the assumption that all costs and usage-capacity relations are linear, to include an equilibrium relation between usage and capacity. It is shown that unique equilibrium usages can be computed by inverting a certain matrix whose dimension equals the number of arcs of the network. Simple rules are given that solve the optimal timing problem in which limits on the change in capacity per period and budgetary constraints are imposed. These procedures do not appear to place serious restrictions on the size of the networks that may be considered in applications.
Safety Analysis for Automated Transportation Systems
Authors: Rahimi A. , Hajdu L. P. , Macomber H. L.
Published: October 2008

This paper outlines an approach to analyzing the safety characteristics of vehicular ground transportation systems operated under computer surveillance and control. A quantitative index of safety is formulated, and a procedure is developed for analyzing the dependence of system safety on the significant design parameters and performance attributes. Lower bounds on the permissible minimum headway are established on the assumption of instantaneous and perfect control, so that the effects of various sensing, communication, control and actuation subsystems can be assessed independently. Time delays in emergency control—resulting from discrete sensor spacing, finite sampling time, and loss of telemetered data—are analyzed and expressions for the attendant increase in the minimum headway are developed. The general approach and the specific techniques are illustrated with numerical examples.
Book of Interest
Authors: Hauer E.
Published: October 2008

A review and recommendation of the book Einführung in die Theorie des Verkehrsflusses, Wilhelm Leutzbach, Springer-Verlag, Berlin, 1972, 155 pages, $6.10 (U.S.).
Network Design with Fixed and Variable Cost Elements
Authors: Billheimer John W. , Gray Paul
Published: October 2008

A route selection algorithm is presented far designing transportation networks. The algorithm balances fixed construction costs and variable user costs in a network having a fixed set of nodes and a known demand, for internode service. The problem solved is a special case of the fixed-cost, multicommodity transshipment problem in which each commodity has a single, unique source node. The route selection algorithm alternatively applies link elimination and link insertion criteria that converge to a local optimum. Upper and lower bounds on the fixed and variable portions of the globally optimum solution are determined and the sensitivity of the solution is estimated. Unique rules are formulated for identifying links that must or must not appear in the globally optimum solution. The solution procedure has been coded for a digital computer and demonstrated using a representation of Minneapolis-St. Paul having 68 nodes and 476 potential oneway links.
Traffic Density Estimation for Single and Multilane Traffic
Authors: Knapp Charles H.
Published: October 2008

Modifications are proposed for an algorithm that estimates the number of vehicles on a section, of highway from a time series of flow and velocity measurements. The effect of alternate assumptions concerning the nature of the velocity field between points of measurement is explored. In addition a simplification is proposed to avoid solution by successive approximation of certain transcendental equations. The net result is an algorithm that is more practical and provides generally superior performance than the original. Various algorithms are evaluated for both single and multilane traffic.
Optimal Scheduling Policies for Some Simple Transportation Systems
Authors: Barnett Arnold , Kleitman Daniel J.
Published: October 2008

A transportation system is operated with one vehicle and several service points. Travel times between adjacent stops are random variables whose distribution functions are unchanged over a given period of time. The problem is to devise the scheduling strategy that minimizes average waiting time for passengers of the system. From the calculus of variations, and the principles advanced by Osuna and Newell for dealing with such problems, we are able to obtain a precise and simple statement of optimal policy for systems with one terminal stop at which interval control can be exerted. The special case of a two-stop line is analyzed in detail. An approximate optimal policy for systems with two terminals, very closely related to the one-terminal optimal strategy, is also suggested.
Letter to the Editor—A Note on the Bus Crew Scheduling Methods of Bennett and Potts
Authors: Byrne J. L.
Published: October 2008

An investigation of the application of the bus crew scheduling methods of Bennett and Potts to the scheduling operations of the Brisbane City Council transport services has revealed that variations in the industrial award conditions significantly affect the method of solution. These variations are discussed briefly and some suggestions are made that improve the computational efficiency of the general method.
The Calculation of Aircraft Collision Probabilities
Authors: Bellantoni J. F.
Published: October 2008

The basic limitation on air traffic compression, from the safety point of view, is the increased risk of collision due to reduced separations. In order to evolve new procedures, and eventually a fully automatic system, it is desirable to have a means of calculating the collision probability for any prescribed flight paths. This paper extends the statistical-probabilistic method of collision probability calculation, which has been limited to parallel, straight line flight paths, to arbitrary flight paths and vehicle shapes. The general formula is specialized to the cases of large relative velocity, nonzero relative velocity, zero relative velocity, and spherical collision surface. The formulas are applied to independent curved landing approaches to parallel runways.
Letter to the Editor—Extensions of the Augmented Predecessor Index Method to Generalized Network Problems
Authors: Glover F. , Klingman D. , Stutz J.
Published: October 2008

The augmented predecessor indexing method is a procedure for efficiently updating the basis representation, flows, and node potentials in an adjacent extreme point (or “simplex” type) method for network problems, utilizing ideas due to Ellis Johnson in his proposed application of a triple-label representation to networks. The procedure is extended here to accommodate the more complex basis structures and updating processes of the generalized network problem, specifying rules for expediting the calculations.
An Algorithm for Combining Truck Trips
Authors: Gavish B. , Schweitzer P.
Published: October 2008

This paper presents a method for serial combination of truck trips to minimize the total cost of deadheading, subject to constraints on the allowed combinations. The problem is initially formulated as an integer transportation problem with extra compatibility constraints, and then reduced to a classical transportation problem. Modifications of the classical algorithm led to a fifty-fold reduction in computer time, and permit solution of a 1000 × 1000 problem in less than two minutes of computer time. Implementation of the method led to considerable cost savings over the older manual procedure.
Ship Congestion at a Scheduled Draw Bridge
Authors: van Daal J. , van Doeland F.
Published: October 2008

The railway bridge at Dordrecht (Holland) can be raised to let big ships pass through. This takes place according to a fixed daily time schedule derived from the railway timetable. The waiting times of the ships depend on the number and the duration of these openings, the headway of the unraised bridge (changing on account of tidal effects), and the traffic supply. In this paper the dependence of the waiting times on the above-mentioned factors is quantified by means of a Monte Carlo simulation procedure.
A Note on Finding All Shortest Paths
Authors: Glover Fred , Klingman D. , Napier A.
Published: October 2008

We present a procedure for finding the shortest routes between all pathconnected ordered pairs of nodes in a network. Furthermore, our approach is quite simple and highly efficient for a special class of network problems. In particular, this class of networks subsumes a number that appear in real world applications. For instance, the Polish government and the Texas Water Resources Developmental Board have developed water resource analysis models that are in this class.
Urban Traffic Speeds—II: Relation of the Parameters of Two Simpler Models to Size of the City and Time of Day
Authors: Hutchinson T. P.
Published: October 2008

Using the data collected by the RRL in 1967 for eight English cities, average speeds on major roads have been calculated as a function of distance from the city center. Two rather simple types of function have been fitted to this empirical data, namely v = k · r1/3 and v = 60 − a · e−r/R, and the values of their parameters have been found to be related to the city size and to whether the observations were made in the peak or the off-peak periods. Data from other studies, in London and Göteborg (Sweden), are adduced to support the conclusions drawn.
A Mathematical Model for Predicting the Duration of Potential Conflict Situations at Intersecting Air Routes
Authors: Siddiqee Waheed
Published: October 2008

A mathematical model is developed for predicting the expected duration of potential conflict situations at the intersection of air routes in the en route environment. Given the intersection angle of two routes and the average flows and speeds of aircraft, the model provides an estimate of the average duration of a potential conflict and the total time the aircraft would spend in potential conflict if no preventive action were taken by controllers or pilots. The model can be used in planning air route network geometry, as well as in providing guidelines to the establishment of suitable levels of traffic flow along various routes.
Over-the-Road Transit Time for a Single Track Railway
Authors: Petersen E. R.
Published: October 2008

This paper develops an analytic model of the mean running time for trains on a single track railway. Trains operating at several different speeds in each direction are permitted. Priority systems are included in the model to control train behavior when meets and overtakes occur and delay times due to implementing these priority schemes are calculated. It is assumed that the departing times for trains are independent random variables that are uniformly distributed over the time period of interest. The resulting mean running times, including delays, for each speed class in each direction are found by solving a set of linear equations.
Letter to the Editor—On Finding the Absolute and Vertex Centers of a Tree with Distances
Authors: Halfin S.
Published: October 2008

We show that a modification of an algorithm that was proposed by A. J. Goldman yields a simpler and more efficient method to locate the absolute and vertex centers of a tree.
Books of Interest
Authors: Beckmann Martin J. , Stopher Peter R. , Dafermos Stella
Published: October 2008

Review of books: (1) Transportation Investment Planning by Martin Wohl, Lexington Books, D.C. Heath and Company, Lexington, Massachusetts, 1972, 152 pages, $15.00; (2) Analytical Transport Planning, R. Lane, T. J. Powell, and P. Prestwood-Smith, Duckworth, London, 1971, 278 pages, £3.95; (3) Flows in Transportation Networks, Renfrey R. Potts, and Robert M. Oliver, Academic Press, New York, 1972, 192 pages, $11.95.
On Controlling Randomness in Transit Operations
Authors: Barnett Arnold
Published: October 2008

In many transit systems, vehicles depart their originating stops at fixed intervals, but headways become increasingly irregular as they move along the line. This paper considers how best to control such randomness through a strategy based on holding individual vehicles at a chosen control stop. An algorithm is presented for constructing an approximate optimal dispatching strategy from the control point, where optimal is defined both in terms of average passenger wait at the control stop and average delay for riders already aboard the vehicle. The algorithm is used on actual operations data from a Boston subway line to propose service improvements.
Books of Interest
Authors: Hurdle VanOlin F. , McGillivray Robert G.
Published: October 2008

Review of books: (1) Traffic Engineering: Theory and Practice, Louis J. Pignataro, Prentice-Hall, Inc., Englewood Cliffs, New Jersey, 1973, 502 pp., $21.00; (2) “Proceedings of the ORSA/TSS Urban Transportation Workshop,” Published in 1973 by the Transportation Science Section of the Operations Research Society of America, 119 pages, $5.00.
The Transportation-Production Problem
Authors: Leblanc Larry J. , Cooper Leon
Published: October 2008

A transportation-production problem with increasing marginal production costs and linear shipping costs is considered. This problem is shown to be a convex programming problem, and an efficient iterative solution technique is presented. Numerical results are presented for various problems having 2,500 variables, 100 linear constraints, and 2,500 nonnegativity constraints. As expected, the number of iterations for an accurate solution depends on the degree of non-linearity of the objective function. Computing times on the CDC Cyber 70, Model 72, varied from 10 to 70 seconds among the different problems.
Measurement of User's Preferences for Public Transportation through Computer Assisted Interviews
Authors: Kalfon Charles , Yordon Wesley , Menkes Joshua
Published: October 2008

Citizens' preferences concerning bus transportation in Boulder, Colorado, were ascertained by two different but related techniques. The primary method was through a computerized game (’CARTFED,’ or Computer-Aided-Real-Time-Feedback Decision) in which subjects are asked to design a desirable bus system by choosing values for system characteristics. Subject's enter these in a portable computer-terminal and the computer calculates and reports the associated deficit, whereupon subjects reiterate making trade-offs to reduce the deficit to an acceptable level. In order to program the computer to calculate the deficits associated with, a wide variety of systems, it was necessary to estimate cost and revenue functions. Since the latter depends upon demand, a prerequisite to the CARTFED program-was the estimation of citizens' preferences by a different technique, which took the form of a questionnaire survey in which respondents were presented with randomly-generated profiles of possible bus systems and asked how often they would use such a system. Multiple regression analysis of the responses yielded the demand function necessary for the CARTFED program. This paper describes both techniques and their results.
Letter to the Editor—Solution to an Integral Equation in the Study of Semi-Poisson Headway Distributions
Authors: Weiss George H.
Published: October 2008

Recently Wasielewski [Trans. Sci. 8, 237–247, (1974)] fitted some data to the semi-Poisson headway distribution. We show that the fundamental integral equation in that paper can be solved in closed form.
Books of Interest
Authors: Sparks Gordon A. , Bergan Arthur T. , Smeed R. J.
Published: October 2008

Review of books: (1) Highways, 2nd ed., C. A. O'Flaherty (Vol. I, Highways and Traffic, 390 pages, Vol. II, Highway Engineering, 457 pages), Edward Arnold Ltd., London, 1974, $23.75 each; (2) Compact City: A Plan for a Liveable Urban Environment, George B. Dantzig and Thomas L. Saaty, W. H. Freeman and Company, San Francisco, 1973, 244 pp., cloth cover, $9.00, paper cover, $4.50.
Demand Functions, Behavioral Analysis, and Cost Effectiveness in Urban Transportation
Authors: Dodson Edward N.
Published: October 2008

The sensitivity of cost-benefit assessments to variations in demand for public transportation is examined. The analysis, based upon detailed computer simulations of urban transportation systems, indicates some major changes in costs and benefits for different demand conditions. However, the relative standing of new systems of urban transportation were not significantly affected. Also discussed are requirements for improved modeling of demand.
Erratum
Authors: Florian Michael , Nguyen Sang , Ferland Jacques
Published: October 2008

Erratum to “On the Combined Distribution-Assignment of Traffic,” Trans. Sci. 9, 43–53 (1975)” by Michael Florian, Sang Nguyen, and Jacques Ferland.
An Algorithm for the Discrete Network Design Problem
Authors: Leblanc Larry J.
Published: October 2008

This paper addresses the problem of determining which links should be improved in an urban road network so that total congestion in the city is minimized. A nonlinear mixed integer programming model is developed, and strategies for a branch-and-bound algorithm are presented. Particular attention is paid to the computational aspects of large-scale problems, and numerical results are reported.
A Combined Trip Generation and Distribution Model
Authors: Cesario Frank J.
Published: October 2008

We develop a model useful for analyzing and predicting trip generation, trip distribution, or both at the aggregate level of analysis. The generation component of the model is structured around the fundamental notion of a diminishing marginal effect of accessibility on tripmaking; the distribution component is a variant of the familiar gravity model. This new approach is seen to overcome many of the shortcomings of conventional models. For example, it is shown that (a) under certain conditions the combined model has structural properties that are fully consistent with substitution principles of microeconomics and (b) supply-demand feedbacks are explicitly taken into consideration. Organizationally, the modeling postulates first are set forth. Then, the combined model is formally developed and its structural (behavioral) properties are enumerated. Finally, an application is provided.
The Application of Location Models to Off-Airport Terminals
Authors: Poulton Michael C. , Kanafani Adib
Published: October 2008

Off-airport terminals have been studied by Snell and Hazen (Snell, J. E., D. C. Hazen. 1970. A first approximation satellite terminal system evaluation model—FASTSEM. Report 103, Transportation Systems Engineering, Department of Civil and Geological Engineering, Princeton University, Princeton.), who evaluated the benefits obtainable from optimally located terminals. The location of off-airport terminals was studied by Kanafani (Kanafani, A. K. 1972. Location models of off-airport terminals. Trans. Res. 6 371–379.), who proposed a number of models to optimize the travel time savings obtainable from terminals located in an idealized linear city. This paper attempts to extend the approach proposed by Kanafani and to apply the resulting models to a case study. Only the location problem is dealt with in this paper and, for that, only travel-time savings obtained by connecting the terminal to the airport with an exclusive mass transit system are considered. Poulton (Poulton, M. C. 1974. The location of off-airport terminals. PhD dissertation, University of California, Institute of Transportation and Traffic Engineering, Berkeley (Dissertation Series).) considered other benefits of off-airport terminals taking into account potential savings in airport terminal congestion.
Book of Interest
Authors: Nguyen Sang
Published: October 2008

A review and recommendation of the book Optimization of Transport Networks, Peter A. Steenbrink, John Wiley & Sons, Somerset, New Jersey, 1974, 325 pages, $22.00.
Traffic Density Estimation with Consideration of Lane-Changing
Authors: Chang Man-Feng , Gazis Dunos C.
Published: October 2008

The, Kalman filtering methodology developed in the past for the density estimation of a roadway section is extended to include explicit consideration of lane-changing on a multilane freeway. It is found that the estimation error may be reduced in this fashion, the reduction ranging up to as much as 40 percent. As is to be expected, the reduction of error in greater when the roadway section is longer arid hence the number of lane-changes greater.
Presence of Donor-Derived DNA and Cells in the Urine of Sex-Mismatched Hematopoietic Stem Cell Transplant Recipients: Implication for the Transrenal Hypothesis
Authors: Hung Emily C W , Shing Tristan K F , Chim Stephen S C , Yeung Philip C , Chan Rebecca W Y , Chik Ki W , Lee Vincent , Tsui Nancy B Y , Li Chi-Kong , Wong Cesar S C , Chiu Rossa W K , Lo Y M Dennis
Published: October 2008

Background: The term “transrenal DNA” was coined in 2000 to signify that DNA in urine may come from the passage of plasma DNA through the kidney barrier. Although DNA in the urine has the potential to provide a completely noninvasive source of nucleic acids for molecular diagnosis, its existence remains controversial.

Methods: We obtained blood and urine samples from 22 hematopoietic stem cell transplant (HSCT) recipients and used fluorescence in situ hybridization, PCR for short tandem repeats, mass spectrometry, quantitative PCR, and immunofluorescence detection to study donor-derived DNA in the urine.

Results: All HSCT recipients exhibited high amounts of donor-derived DNA in buffy coat and plasma samples. Male donor–derived DNA was detected in supernatants of urine samples from all 5 female sex-mismatched HSCT recipients. Surprisingly, the amount of DNA in urine supernatants was not correlated with the plasma value. Moreover, cell-free urine supernatants contained DNA fragments >350 bp that were absent in plasma. Donor-derived polymorphs were detected in urine by fluorescence in situ hybridization. Coincidentally, donor-derived cytokeratin-producing epithelial cells were discovered in urine samples from 3 of 10 sex-mismatched HSCT recipients as long as 14.2 years after transplantation.

Conclusions: This report is the first to demonstrate the presence of donor-derived DNA in the urine of HSCT recipients; however, we show that much of this DNA originates from donor-derived cells, rather than from the transrenal passage of cell-free plasma DNA. Our discovery of donor-derived cytokeratin-producing epithelial cells raises interesting biological and therapeutic implications, e.g., the capacity of marrow stem cells to serve as an extrarenal source for renal tubule regeneration.
Lateral Flow Immunoassay Using Europium Chelate-Loaded Silica Nanoparticles as Labels
Authors: Xia Xiaohu , Xu Ye , Zhao Xilin , Li Qingge
Published: October 2008

Background: Despite their ease of use, lateral flow immunoassays (LFIAs) often suffer from poor quantitative discrimination and low analytical sensitivity. We explored the use of a novel class of europium chelate-loaded silica nanoparticles as labels to overcome these limitations.

Methods: Antibodies were covalently conjugated onto europium chelate-loaded silica nanoparticles with dextran as a linker. The resulting conjugates were used as labels in LFIA for detection of hepatitis B surface antigen (HBsAg). We performed quantification with a digital camera and Adobe Photoshop software. We also used 286 clinical samples to compare the proposed method with a quantitative ELISA.

Results: A detection limit of 0.03 μg/L was achieved, which was 100 times lower than the colloidal gold-based LFIAs and lower than ELISA. A precise quantitative dose-response curve was obtained, and the linear measurement range was 0.05–3.13 μg/L, within which the CVs were 2.3%–10.4%. Regression analysis of LFIA on ELISA results gave: log (LFIA) = −0.14 log (ELISA) + 1.03 μg/L with r = 0.99 for the quantification of HBsAg in 35 positive serum samples. Complete agreement was observed for the qualitative comparison of 286 clinical samples assayed with LFIA and ELISA.

Conclusions: Europium chelate-loaded silica nanoparticle labels have great potential to improve LFIAs, making them useful not only for simple screening applications but also for more sensitive and quantitative immunoassays.
Aromatase expression in the normal human adult adrenal and in adrenocortical tumors: biochemical, immunohistochemical, and molecular studies
Authors: Moreau François , Mittre Hervé , Benhaim Annie , Bois Camille , Bertherat Jérome , Carreau Serge , Reznik Yves
Published: October 2008

Objective

The aromatase enzyme catalyzes the final stage of estrogen biosynthesis pathway from androgens. Its expression in the adrenal is poorly studied except for the rare estrogen-producing adrenocortical tumors. In order to further characterize aromatase expression in the adrenal, we evaluated the aromatase enzyme activity, Cyp19a1 gene expression level, and promoter utilization in normal adrenal tissues and in adrenocortical secreting tumors.

Design and methods

Six normal adult adrenals (NA), 2 feminizing adrenal tumors (FT), 10 cortisol-producing adenomas with overt (CS, n=4) or sub-clinical Cushing syndrome (SCS, n=6) and 3 aldosterone-producing adenomas (APA) were studied. Tissue aromatase activity was determined by the tritiated (3H)-water method. Total aromatase mRNA were measured by a competitive RT-PCR. Promoter regions PII and PI.4-derived transcripts were also studied in NA, FT, and other steroid-producing tumors by a semi-quantitative comparative RT-PCR. Immunofluorescence analysis was performed in normal human adrenal tissues.

Results

Aromatase activity was detected in NA tissues and in all tumor subtypes, at high levels in both FT. In NA, aromatase immunofluorescence was detected in the cytoplasm of steroidogenic cells, mainly from zona reticularis. Compared with NA, aromatase transcript levels were similar in CS and APA, lower in SCS and similar or higher in FT. Promoter analysis suggested predominant PII utilization in NA, APA, and SCS, but similar PII and PI.4 utilization in CS tumors.

Conclusion

Aromatase is expressed at similar levels in normal adrenal and in adrenocortical tumors, but at variably high levels in FT. Different promoter utilization patterns are found among tumor subtypes.
Age and stress as determinants of the severity of hyperthyroidism caused by Graves' disease in newly diagnosed patients
Authors: Vos Xander G , Smit Natalie , Endert Erik , Brosschot Jos F , Tijssen Jan G P , Wiersinga Wilmar M
Published: October 2008

Objective

The evidence that stress may provoke Graves' hyperthyroidism in genetically susceptible subjects is substantial. Whether exposure to stress is related to the severity of thyrotoxicosis has not been studied. Advancing age is associated with not only less severe Graves' hyperthyroidism but also self-reported stress. We tested the hypothesis whether advancing age is associated with less exposure to stress, resulting in a lower immunological response, and less severe Graves' hyperthyroidism.

Design

Cross-sectional multicenter study.

Patients

Two hundred and sixty-three consecutive untreated patients with a first episode of Graves' hyperthyroidism were included. The severity of Graves' hyperthyroidism was evaluated biochemically (freeT4-index and freeT3-index, thyrotropin-binding inhibitory immunoglobulin (TBII)) and clinically by the hyperthyroid symptom scale score (HSS score). Stress exposure was quantitated by three questionnaires.

Results

Advancing age was associated with less severe Graves' hyperthyroidism, both biochemically by lower serum freeT3-index and freeT4-index (P<0.01), lower serum TBII (P=0.05), and clinically by lower HSS scores (P=0.04) and smaller goiter size (P<0.01). FreeT3-index and freeT4-index were directly associated with HSS scores (P<0.01). Stress scores were associated with HSS scores (P<0.01) but not with biochemical severity of Graves' hyperthyroidism. Advancing age was associated with lower scores for stress exposure. Multivariate regression analysis showed that HSS score was independently related to the tendency to report negative feelings (P<0.01) but not to other stress scores and also not to age.

Conclusion

Advancing age is associated with less exposure to stress, lower serum TBII and less severe clinical and biochemical Graves' hyperthyroidism. Because no direct relationship exists between stress exposure and TBII or freeT3-index and freeT4-index, we reject our hypothesis that less stress is causally related to biochemically less severe Graves' hyperthyroidism in old age. HSS score is primarily determined by negative feelings and not by age.
Is there a further acceleration in the age at onset of menarche? A cross-sectional study in 1840 school children focusing on age and bodyweight at the onset of menarche
Authors: Bau A M , Ernert A , Schenk L , Wiegand S , Martus P , Grüters A , Krude H
Published: October 2008

Objective

More than 30 years ago Frisch and Revelle proposed a body weight threshold for the onset of menarche. Based on this hypothesis, a further acceleration of age at menarche can be expected in times of childhood obesity.

Design

A cross-sectional study of 1840 healthy school girls (Berlin school children's cohort, BSCOC) within the age groups 10–15 years was conducted in 2006–2007.

Methods

Median age of menarche was calculated by Kaplan–Meier survival analysis. Bi- and multivariate analyses were performed to analyze the associations between menarche age and weight status. A locally weighted regression was used to analyze the relationship respectively between height, weight, and body mass index (BMI)–SDS and age stratified by menarche status.

Results

Nine hundred and thirty six (50.9%) girls had already experienced menarche at a median age of 12.8 years. Two hundred and thirty six of these girls reached their menarche recently. Obese/overweight girls reached menarche significantly earlier (12.5 years), than normal weight (12.9 years), and underweight girls (13.7 years). The mean total body weight was similar in all girls at menarche irrespective of age (mean 51.1 kg,s.d.8.1) and height. BMI–SDS remained the only significant factor for onset of menarche within a multiple regression model for early menarche (OR 2.1, 95% confidence interval 1.3–3.3,P=0.002).

Conclusions

Age at onset of menarche did not accelerate even in a childhood population with more than 10% obesity prevalence. Nevertheless, a negative correlation of BMI–SDS with age at onset of menarche exists.
Health-related quality of life and IGF-1 in GH-deficient adult patients on GH replacement therapy: analysis of the German KIMS data and the Study of Health in Pomerania
Authors: Moock Joern , Albrecht Christin , Friedrich Nele , Völzke Henry , Nauck Matthias , Koltowska-Haggström Maria , Kohlmann Thomas , Wallaschofski Henri
Published: October 2008

Objective

To analyse 12-month response to GH treatment in a single-country cohort of hypopituitary adult patients with GH deficiency (GHD) in regards to health-related quality of life (HRQoL) and insulin-like growth factor-1 (IGF-1) compared with values from general population sample. Moreover, association between the response in HRQoL and the IGF-1 values in patients and in the background population was investigated.

Design

HRQoL was assessed by quality of life assessment of GH deficiency in adults (QoL-AGHDA) in 651 patients retrieved from the German KIMS (Pfizer International Metabolic Database) before and after 12 months of GH replacement and in a sample drawn from a cross-sectional study in Germany (n=2734). IGF-1 was measured in KIMS patients and in the population-based study with the same assay technique.

Results

In KIMS patients, mean QoL-AGHDA scores before GH replacement were 9.2±6.8 (8.7±6.8) in women (men) and in the general population sample 4.5±5.3 (4.3±5.0) in women (men). Mean differences in QoL-AGHDA scores were statistically significant for all age categories (P<0.05). The mean IGF-1 SDS of KIMS patients before GH replacement was −1.1±1.4 (−0.8±1.4) in women (men). After GH replacement, a significant increase of IGF-1 concentration and a significant decrease of QoL-AGHDA scores near to age- and gender-specific population-based values were observed.

Conclusions

This study confirms an improvement in HRQoL and an increase of IGF-1 SDS in GH-replaced adults, which approximated the values of general population. However, there was no association between IGF-1 values and HRQoL assessment as one of the important treatment outcomes.
Newborn Resuscitation and the Lung
Authors: Bry Kristina
Published: October 2008

Approximately 10% of newborns require some assistance to begin breathing at birth. The lung plays a central role in neonatal resuscitation. Rapid clearance of lung fluid and a tenfold increase in pulmonary blood flow caused by a dramatic fall in pulmonary vascular resistance are essential for gas exchange. Failure to make a smooth transition from fetal to neonatal life leads to a need for resuscitation at birth. Traditionally, babies have been resuscitated using 100% oxygen, but evidence now suggests that use of 100% oxygen during resuscitation may be harmful, and excessive use of oxygen, therefore, should be avoided. Pulse oximetry may help to guide inspired oxygen delivery. Effective ventilation is the key to successful neonatal resuscitation. Because excessive tidal volumes and pressures cause lung injury, the minimal inflation required to achieve an increase in heart rate should be used. In preterm babies, starting resuscitation with continuous positive airway pressure or positive end-expiratory pressure may help to improve oxygenation, stabilize the airway, and establish functional residual volume. As a result of recent studies, the recommendations for the care of meconium-stained infants have been changed; routine intrapartum suctioning of such infants no is longer recommended. Meconium-stained, depressed infants should receive intratracheal suctioning immediately after birth and before stimulation, but tracheal suctioning is not necessary for vigorous babies who have meconium-stained amniotic fluid.
Burden of Rotavirus Disease Among Children Visiting Pediatric Emergency Departments in Cincinnati, Ohio, and Oakland, California, in 1999–2000
Authors: Yee Eileen L. , Staat Mary Allen , Azimi Parvin , Bernstein David I. , Ward Richard L. , Schubert Charles , Matson David O. , Turcios-Ruiz Reina M. , Parashar Umesh , Widdowson Marc-Alain , Glass Roger I.
Published: October 2008

OBJECTIVE. We assessed the incidence of rotavirus disease requiring an emergency department visit among children <5 years of age.

METHODS. We conducted active surveillance for acute gastroenteritis in pediatric emergency departments in Cincinnati, Ohio, and Oakland, California, from March 1999 to May 2000, among children 2 weeks to 59 months of age with acute diarrhea and/or vomiting. We obtained clinical and demographic information from participants and tested their stool specimens for rotavirus.

RESULTS. Approximately 9% of all emergency department visits at the study sites were attributable to acute gastroenteritis. A total of 1433 children were eligible at the 2 sites; 85% were enrolled and 68% provided a stool specimen. Overall, rotavirus was detected in specimens from 27% of children (30% in Cincinnati and 24% in Oakland). Rotavirus detection was higher in bulk stools, compared with rectal swabs, at both Cincinnati (37% vs 23%) and Oakland (46% vs 18%). Patients with rotavirus had more-severe disease than did those with nonrotavirus gastroenteritis. We estimated that the mean annual incidence of emergency department visits attributable to rotavirus was 12 cases per 1000 children in Cincinnati and 15 cases per 1000 children in Oakland. Through extrapolation, we estimated that rotavirus infection causes ∼260 910 emergency department visits per year among US children.

CONCLUSION. Active surveillance demonstrated that the burden of laboratory-confirmed rotavirus disease treated in emergency department settings among US children is substantial and greater than estimated previously.
Effectiveness of a Mentor-Implemented, Violence Prevention Intervention for Assault-Injured Youths Presenting to the Emergency Department: Results of a Randomized Trial
Authors: Cheng Tina L. , Haynie Denise , Brenner Ruth , Wright Joseph L. , Chung Shang-en , Simons-Morton Bruce
Published: October 2008

OBJECTIVE. The goal was to assess the impact of a mentor-implemented, violence prevention intervention in reducing aggression, fighting, and reinjury among assault-injured youths.

METHODS. In a randomized, controlled trial performed in the emergency departments of 2 large urban hospitals, 10- to 15-year-old youths who presented with peer assault injuries were recruited and randomly assigned to intervention and comparison groups. In the intervention group, youths received a mentor, who implemented a 6-session problem-solving curriculum, and parents received 3 home visits with a health educator, to discuss family needs and to facilitate service use and parental monitoring. The comparison group received a list of community resources, with 2 follow-up telephone calls to facilitate service use. Youths and parents were interviewed at baseline and at 6 months, for assessment of attitudes about violence, risk factors, fighting, and repeat injury.

RESULTS. A total of 227 families were recruited, with 23% refusing participation and 4% providing partial interview completion. A total of 166 families were enrolled, with 87 assigned to the intervention group and 79 to the comparison group; 118 (71%) completed both youth and parent follow-up interviews, and 113 had usable data. The intervention and comparison groups were not significantly different at baseline with respect to demographic features or risk factors, except for increased knife-carrying and fewer deviant peers in the intervention group. After adjustment for baseline differences, there was a trend toward significant program effects, including reduced misdemeanor activity and youth-reported aggression scores and increased youth self-efficacy. Program impact was associated with the number of intervention sessions received.

CONCLUSIONS. A community-based, mentor-implemented program with assault-injured youths who presented to the emergency department trended in the direction of decreased violence, with reduced misdemeanors and increased self-efficacy.
Influenza Vaccination in Adolescents With High-Risk Conditions
Authors: Nakamura Mari M. , Lee Grace M.
Published: October 2008

OBJECTIVES. We assessed influenza vaccination rates from 1992 to 2002, individual continuity of vaccination, and missed opportunities for vaccination in adolescents with high-risk conditions.

METHODS. We performed a retrospective observational study of 18 703 adolescents with high-risk conditions who were enrolled in a large health maintenance organization and received care at a multisite practice for ≥1 influenza season and the preceding year, between 1992 and 2002, was performed. Subjects were identified as having a high-risk condition if they had ≥1 visit with an associated International Classification of Diseases, Ninth Revision, Clinical Modification code during the season or previous year. Influenza vaccination rates were compared by season in logistic regression analyses, using generalized estimating equations for repeated measurements of subjects enrolled for multiple seasons. Vaccination continuity was measured for adolescents who were enrolled for 4 consecutive seasons (1999–2002) as the number of seasons during which vaccine was received. Missed opportunities were defined as visits during the first 4 months of influenza season at which an unvaccinated adolescent did not receive vaccine.

RESULTS. For adolescents with high-risk conditions, influenza vaccination rates varied from 8.3% to 15.4%. Rates improved significantly from 1992 to 1993, from 8.3% to 12.8%, and again in 2001, reaching 15.4%. Only 11.1% of those enrolled continuously from 1999 to 2002 received vaccine during all 4 seasons. According to season from 1992 to 2002, 45.7% to 53.6% of unvaccinated subjects had ≥1 missed opportunity.

CONCLUSIONS. Influenza vaccination rates in adolescents with high-risk conditions improved from 1992 to 2002 but were still low in recent years. Individual vaccination continuity was poor. Numerous opportunities already exist for improving coverage.
Vaccine Effectiveness Against Laboratory-Confirmed Influenza in Children 6 to 59 Months of Age During the 2003–2004 and 2004–2005 Influenza Seasons
Authors: Eisenberg Katherine W. , Szilagyi Peter G. , Fairbrother Gerry , Griffin Marie R. , Staat Mary , Shone Laura P. , Weinberg Geoffrey A. , Hall Caroline B. , Poehling Katherine A. , Edwards Kathryn M. , Lofthus Geraldine , Fisher Susan G. , Bridges Carolyn B. , Iwane Marika K. ,   and the New Vaccine Surveillance Network
Published: October 2008

OBJECTIVE. The goal was to estimate the effectiveness of influenza vaccination against laboratory-confirmed influenza during the 2003–2004 and 2004–2005 influenza seasons in children 6 to 59 months of age.

METHODS. We conducted a case-control study with children with medically attended, acute respiratory infections who received care in an inpatient, emergency department, or outpatient clinic setting during 2 consecutive influenza seasons. All children residing in Monroe County, New York, Davidson County, Tennessee, or Hamilton County, Ohio, were enrolled prospectively at the time of acute illness and had nasal/throat swabs tested for influenza with cultures and/or polymerase chain reaction assays. Children with laboratory-confirmed influenza were case subjects and children who tested negative for influenza were control subjects. Child vaccination records from the parent and the child's physician were used to determine and to validate influenza vaccination status. Influenza vaccine effectiveness was calculated as (1 − adjusted odds ratio) × 100.

RESULTS. We enrolled 288 case subjects and 744 control subjects during the 2003–2004 season and 197 case subjects and 1305 control subjects during the 2004–2005 season. Six percent and 19% of all study children were fully vaccinated according to immunization guidelines in the respective seasons. Full vaccination was associated with significantly fewer influenza-related inpatient, emergency department, or outpatient clinic visits in 2004–2005 (vaccine effectiveness: 57%) but not in 2003–2004 (vaccine effectiveness: 44%). Partial vaccination was not effective in either season.

CONCLUSIONS. Receipt of all recommended doses of influenza vaccine was associated with halving of laboratory-confirmed influenza-related medical visits among children 6 to 59 months of age in 1 of 2 study years, despite suboptimal matches between the vaccine and circulating influenza strains in both years.
Pediatric Cardiopulmonary Resuscitation: Advances in Science, Techniques, and Outcomes
Authors: Topjian Alexis A. , Berg Robert A. , Nadkarni Vinay M.
Published: October 2008

More than 25% of children survive to hospital discharge after in-hospital cardiac arrests, and 5% to 10% survive after out-of-hospital cardiac arrests. This review of pediatric cardiopulmonary resuscitation addresses the epidemiology of pediatric cardiac arrests, mechanisms of coronary blood flow during cardiopulmonary resuscitation, the 4 phases of cardiac arrest resuscitation, appropriate interventions during each phase, special resuscitation circumstances, extracorporeal membrane oxygenation cardiopulmonary resuscitation, and quality of cardiopulmonary resuscitation. The key elements of pathophysiology that impact and match the timing, intensity, duration, and variability of the hypoxic-ischemic insult to evidence-based interventions are reviewed. Exciting discoveries in basic and applied-science laboratories are now relevant for specific subpopulations of pediatric cardiac arrest victims and circumstances (eg, ventricular fibrillation, neonates, congenital heart disease, extracorporeal cardiopulmonary resuscitation). Improving the quality of interventions is increasingly recognized as a key factor for improving outcomes. Evolving training strategies include simulation training, just-in-time and just-in-place training, and crisis-team training. The difficult issue of when to discontinue resuscitative efforts is addressed. Outcomes from pediatric cardiac arrests are improving. Advances in resuscitation science and state-of-the-art implementation techniques provide the opportunity for further improvement in outcomes among children after cardiac arrest.
Effects of Flow Amplitudes on Intraprong Pressures During Bubble Versus Ventilator-Generated Nasal Continuous Positive Airway Pressure in Premature Infants
Authors: Kahn Doron J. , Habib Robert H. , Courtney Sherry E.
Published: October 2008

OBJECTIVES. The goal were to characterize the flow dependence of bubble nasal continuous positive airway pressure delivery in a cohort of preterm infants and to compare the actual (delivered) intraprong continuous positive airway pressure with the intended (set) nasal continuous positive airway pressure for both ventilator-generated nasal continuous positive airway pressure and bubble nasal continuous positive airway pressure delivery. A range of set values and constant flow rates were studied in the same preterm infants.

METHODS. For 12 premature infants of <1500 g (birth weight: 1140 ± 267 g; gestational age: 28.5 ± 1.9 weeks; study age: 12.9 ± 8 days; all mean ± SD), intraprong pressures were measured at 3 increasing flow settings, repeated for set nasal continuous positive airway pressures (or desired immersion depths) of 4 and 6 cmH2O. Next, intraprong pressures were measured at bubble nasal continuous positive airway pressure expiratory tubing submersion depths and ventilator-generated nasal continuous positive airway pressure set expiratory pressures of 2, 3, 4, 5, and 7 cmH2O while the flow rate was held constant.

RESULTS. Actual (delivered) intraprong pressure during bubble nasal continuous positive airway pressure delivery was highly flow dependent and increased as the flow rate increased. During ventilator-generated nasal continuous positive airway pressure delivery, actual pressure at the nasal prongs closely approximated the pressure set at the ventilator. During bubble nasal continuous positive airway pressure delivery at constant flow rate, the average delivered prong pressure was 1.3 cmH2O (range: 0.5–2.2 cmH2O) higher than that set through submersion of the expiratory tubing, and the relative difference between the set and actual pressures increased at lesser immersion depths.

CONCLUSIONS. Prong pressure during bubble nasal continuous positive airway pressure delivery is highly variable and depends on the interaction of submersion depth and flow amplitudes.