bluuebunny/crossref_metadata_2025 huggingface dataset:
The choice of optimum cross section for overhead line by economic intervals' method
Authors: Guseva Svetlana , Petrichenko Lubov
Published: October 2011

The choice of optimum cross section for overhead line by economic intervals' method

In this paper an approach to choosing the optimum cross section for overhead line in conditions of incomplete and uncertain information is considered. The two methods of such choice are presented: method of economic current density and economic intervals' method. The correction of the economic intervals method is offered under market conditions of costs. As example 20 kV and 110 kV overhead lines with aluminum, copper and ferroaluminum wires are selected. Universal nomograms with different standard cross section are calculated and constructed. The graphics using Mathcad software are offered.
Sensorless Detection of Induction Motor Rotor Faults Using the Clarke Vector Approach
Authors: Vaimann Toomas , Kallaste Ants , Kilk Aleksander
Published: October 2011

Sensorless Detection of Induction Motor Rotor Faults Using the Clarke Vector Approach

Due to their rugged build, simplicity and cost effective performance, induction motors are used in a vast number of industries, where they play a significant role in responsible operations, where faults and downtimes are either not desirable or even unthinkable. As different faults can affect the performance of the induction motors, among them broken rotor bars, it is important to have a certain condition monitoring or diagnostic system that is guarding the state of the motor. This paper deals with induction motor broken rotor bars detection, using Clarke vector approach.
Basic Statements of Research and Magnetic Field of Axial Excitation Inductor Generator
Authors: Stroganovs Igors , Zviedris Andrejs
Published: October 2011

Basic Statements of Research and Magnetic Field of Axial Excitation Inductor Generator

In this work the main features of axial excitation inductor generators are described. Mathematical simulation of a magnetic field is realized by using the finite element method. The objective of this work is to elucidate how single elements shape, geometric dimensions and magnetic saturation of magnetic system affect the main characteristics of the field (magnetic induction, magnetic flux linkage). The main directions of a magnetic system optimization are specified.
Electromechanical Battery, Electrical Machines Mass Functions Analysis
Authors: Podgornovs Andrejs , Sipovics Anton
Published: October 2011

Electromechanical Battery, Electrical Machines Mass Functions Analysis

In this paper different types of electrical machines in electromechanical battery, were described. The most known manufactured battery data is composed. Three types of machines: synchronous machine with salient poles and electromagnetic excitation, with permanent magnets on rotor and reluctance synchronous machine were analyzed. For all types of machines, mass is function of general geometrical size of magnetic system and machines electrical power.
Comparison of Induction Motor Transient Processes Characteristics Obtained Experimentally With Those Obtained by Means of FORTRAN and MATLAB Softwear
Authors: Orlovskis Guntis , Konuhova Marina , Ketners Karlis
Published: October 2011

Comparison of Induction Motor Transient Processes Characteristics Obtained Experimentally With Those Obtained by Means of FORTRAN and MATLAB Softwear

In this article there is made comparison of induction motor real transient processes data given from mathematical model and experimental way. Theoretical investigation of induction motor was executed under two software - MATLAB and FORTRAN. The MATLAB soft induction motor model is created as a completed set. In FORTRAN there is created calculation algorithm. In both above mentioned soft there are fixed similar conditions. It was experimentally examined 300 W induction motor.
The Influence of Pole Pair Number and Magnets' Width on Mechanical Torque of Magnetic Coupler with Rounded Permanent Magnets
Authors: Ose Baiba , Pugachov Vladislav
Published: October 2011

The Influence of Pole Pair Number and Magnets' Width on Mechanical Torque of Magnetic Coupler with Rounded Permanent Magnets

In this paper it is researched the influence of permanent magnets' width and number of pole pairs on the mechanical torque of magnetic coupler with rounded magnets. The mechanical torque is calculated applying the program QuickField. For given magnetic coupler it is found the most suitable design taking into account the number of pole pairs and magnets' width.
Study of Simple MPPT Converter Topologies for Grid Integration of Photovoltaic Systems
Authors: Zakis Janis , Vinnikov Dmitri
Published: October 2011

Study of Simple MPPT Converter Topologies for Grid Integration of Photovoltaic Systems

This paper presents a study of two simple MPPT converter topologies for grid integration of photovoltaic (PV) systems. A general description and a steady state analysis of the discussed converters are presented. Main operating modes of the converters are explained. Calculations of main circuit element parameters are provided.

Experimental setups of the MPPT converters with the power of 800 W were developed and verified by means of main operation waveforms. Also, experimental and theoretical boost properties of the studied topologies are compared.

Finally, the integration possibilities of the presented MPPT converters with a grid side inverter are discussed and verified by simulations.
Lossless Dynamic Models of the Quasi-Z-Source Converter Family
Authors: Vinnikov Dmitri , Husev Oleksandr , Roasto Indrek
Published: October 2011

Lossless Dynamic Models of the Quasi-Z-Source Converter Family

This paper is devoted to the quasi-Z-source (qZS) converter family. Recently, the qZS-converters have attracted attention because of their specific properties of voltage boost and buck functions with a single switching stage, which could be especially beneficial in renewable energy applications. As main representatives of the qZS-converter family, the traditional quasi-Z-source inverter as well as two novel extended boost quasi-Z-source inverters are discussed. Lossless dynamic models of these topologies are presented and analyzed.
Cooling Methods for High-Power Electronic Systems
Authors: Blinov Andrei , Vinnikov Dmitri , Lehtla Tõnu
Published: October 2011

Cooling Methods for High-Power Electronic Systems

Thermal management is a crucial step in the design of power electronic applications, especially railroad traction and automotive systems. Mass/size parameters, robustness and reliability of the power electronic system greatly depend on the cooling system type and performance. This paper presents an approximate parameter estimation of the thermal management system required as well as different commercially available cooling solutions. Advantages and drawbacks of different designs ranging from simple passive heatsinks to complex evaporative systems are discussed.
Intelligent Transformer: Possibilities and Challenges
Authors: Viktor Beldjajev , Indrek Roasto , Tõnu Lehtla
Published: October 2011

Intelligent Transformer: Possibilities and Challenges

This paper covers the concept of an intelligent transformer that is a good candidate to replace a conventional low frequency transformer in the microgrids. As the power production and consumption can vary in a wide range, the new substations have to meet many requirements to guarantee reliable energy management in the autonomous networks. Different topologies of intelligent transformers can be used to meet these requirements. Therefore the advantages and disadvantages of the existing topologies were analyzed. The future trends and challenges are also discussed.
Evaluation of Power Consumption Minimization Approaches for Autonomous Electronic Equipment
Authors: Suzdalenko Alexander , Galkin Ilya
Published: October 2011

Evaluation of Power Consumption Minimization Approaches for Autonomous Electronic Equipment

The use of electronic data logging device is studied for energy minimization approaches. The energy harvesting elements are described and specific design of power supply unit is provided. The main focus is on the minimization of energy loses at conversion and storage stages, as well as software optimisation is discussed, allowing to prolong the autonomous operation of the electronic device. The example of optimized data logger design is presented.
Assessment of Energy Efficient LED Ballasts Based on their Weight and Size
Authors: Milashevski Irena , Tetervenok Oleg , Galkin Ilya
Published: October 2011

Assessment of Energy Efficient LED Ballasts Based on their Weight and Size

LED elements always require some electronic ballast that may consist of a primary power supply and a number of secondary dimmers for light regulation. These circuits can be implemented as DC/DC converters. In the paper buck and boost dimmers are investigated from the point of view of their weight and size, that are close related to their losses. The analysis is provided for various modulation techniques and configurations of the converters. The above mention converters are investigated analytically, through simulation and experimentally.
Effects of Non-smooth Phenomena on the Dynamics of DC-DC Converters
Authors: Pikulin Dmitry
Published: October 2011

Effects of Non-smooth Phenomena on the Dynamics of DC-DC Converters

This paper provides the analysis of nonlinear phenomena in switch-mode power converters. In distinction to majority of known researches this paper presents novelty approach, allowing the complete bifurcation analysis, considering stable and various types of unstable behavior of nonlinear systems. Main results are illustrated on one of the most widely used switching converters - current controlled boost converter, for which the complete one-parametric bifurcation diagrams are constructed. The results include the detection of various types of rare attractors, smooth bifurcations and non-smooth phenomena, specific to piecewise linear dynamical systems.
Preliminary Circuit Design for Robotics Environment Mapping Utilizing Ambient Light, Reflected Light and Stationary Infrared Radiation
Authors: Adrian Leslie
Published: October 2011

Preliminary Circuit Design for Robotics Environment Mapping Utilizing Ambient Light, Reflected Light and Stationary Infrared Radiation

The paper deals with robotics mobility and a proposed topology for the acquisition of the necessary data to enable accurate mapping of a given environment, be that for basic maneuverability, (obstacle avoidance) or for higher level applications such as fire detection or item location. The topology is composed of a four layered system of analogue components which lends itself not only to excellent linearity but allows the system to control peripheral devices directly through any logic configuration, or to provide data needed for microcontrollers and their user defined algorithms. The various layers have been analyzed through simulation and to date confirmed though physical observation of the working model. The conclusions about the prospective solution are made.
The Model of Nonstationary Rotor Magnetic Field Observer in the Induction Motor
Authors: Burkov Alexander , Krasilnikyants Evgenii , Smirnov Alexander
Published: October 2011

The Model of Nonstationary Rotor Magnetic Field Observer in the Induction Motor

This article is devoted to the questions, associated with observer construction for monitoring the values of rotor magnetic vector magnitude and angular deflection of induction motor oriented on bidimensional convolution on temporal and spatial actual parameters. The interrelation of induction motor breakdown torque and rotor characteristic time and transportation lag is shown. The system of rotor running stream observer on the basis of gage rotor position and stator current is put forward.
Double Carrier Pulse width Modulation Control for a Quasi Impedance Source Inverter
Authors: Akrami Amin , Gitizadeh Mohsen , Nayeripour Majid , Ghaderi Mohammad
Published: October 2011

Double Carrier Pulse width Modulation Control for a Quasi Impedance Source Inverter

The quasi-Z-source inverter (QZSI) is similar to the ZSI. The QZSI has been developed which feature several improvements and no disadvantages when compared to the ZSI. Also Double carrier pulse width modulation control is a new control method for controlling the ZSI and it has a lot of benefit if to compare with other traditional control methods. This paper improved properties of the QZSI by using the double carrier pulse width modulation control. Simulation results will be presented to demonstrate the new features.
A Finite Element Implementation of Knowles Stored-Energy Function: Theory, Coding and Applications
Authors: Suchocki Cyprian
Published: October 2011

A Finite Element Implementation of Knowles Stored-Energy Function: Theory, Coding and Applications

This paper contains the full way of implementing a user-defined hyperelastic constitutive model into the finite element method (FEM) through defining an appropriate elasticity tensor. The Knowles stored-energy potential has been chosen to illustrate the implementation, as this particular potential function proved to be very effective in modeling nonlinear elasticity within moderate deformations. Thus, the Knowles stored-energy potential allows for appropriate modeling of thermoplastics, resins, polymeric composites and living tissues, such as bone for example. The decoupling of volumetric and isochoric behavior within a hyperelastic constitutive equation has been extensively discussed. An analytical elasticity tensor, corresponding to the Knowles stored-energy potential, has been derived. To the best of author's knowledge, this tensor has not been presented in the literature yet. The way of deriving analytical elasticity tensors for hyperelastic materials has been discussed in detail. The analytical elasticity tensor may be further used to develop visco-hyperelastic, nonlinear viscoelastic or viscoplastic constitutive models. A FORTRAN 77 code has been written in order to implement the Knowles hyperelastic model into a FEM system. The performance of the developed code is examined using an exemplary problem.
Magnetic Resonance Imaging: Generating a New Pulse in the Physical Therapy Profession
Authors: Elliott James M.
Published: November 2011

The ability to refer for diagnostic tests is particularly relevant to the topic of this special issue on magnetic resonance imaging (MRI). As a doctoring profession, one could argue that the ability to refer a patient for MRI (and other imaging applications) must be available to the direct-access physical therapist. Though the prescription for and use of MRI has not typically been considered within the scope of physical therapist practice, this may be the perfect time to challenge the obstacles precluding the obtainment of such diagnostic privileges and to specifically provide perspective on why and how such a specialized privilege could positively impact the provision of physical therapy services and patient outcomes. An expected obligation of such autonomy, however, is accountability. Is our entire profession adequately prepared to accept the role of, or the responsibilities associated with, referral for imaging privileges?

J Orthop Sports Phys Ther 2011;41(11):803–805. doi:10.2519/jospt.2011.0109
Physical Therapist Practice and the Role of Diagnostic Imaging
Authors: Boyles Robert E. , Gorman Ira , Pinto Daniel , Ross Michael D.
Published: November 2011

Synopsis

For healthcare providers involved in the management of patients with musculoskeletal disorders, the ability to order diagnostic imaging is a beneficial adjunct to screening for medical referral and differential diagnosis. A trial of conservative treatment, such as physical therapy, is often recommended prior to the use of imaging in many treatment guidelines for the management of musculoskeletal conditions. In the United States, physical therapists are becoming more autonomous and can practice some degree of direct access in 48 states and Washington, DC. Referral for imaging privileges could increase the effectiveness and efficiency of healthcare delivery, particularly in combination with direct access management. This clinical commentary proposes that, given the American Physical Therapy Association's goal to have physical therapists as primary care musculoskeletal specialists of choice, it would be beneficial for physical therapists to have imaging privileges in their practice. The purpose of this commentary is 3-fold: (1) to make a case for the use of imaging privileges by physical therapists, using a historical perspective; (2) to discuss the barriers preventing physical therapists from having this privilege; and (3) to offer suggestions on strategies and guidelines to facilitate the appropriate inclusion of referral for imaging privileges in physical therapist practice. J Orthop Sports Phys Ther 2011;41(11):829–837. doi:10.2519/jospt.2011.3556
Epoxy-Montmorillonite Nanocomposites Applied to Powder Coatings
Authors: Piazza D. , Lorandi N. P. , Rieder E. S. , Scienza L. C. , Zattera A. J.
Published: November 2011

The wide range of applications associated with nanocomposites is due to their improved properties when compared to conventional composites. In this study, commercial epoxy-based powder coatings were formulated with 2 and 4% (w/w) of an organically modified montmorillonite (OMMT) by incorporation in the melt state (extrusion). These composites were characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), transmission electron microscopy (TEM) and X-ray diffraction (XDR). The thermal behavior and stability of the epoxy nanocomposites were studied by TGA and DSC. The nanoparticle structure within the polymer matrix was analyzed by XRD and TEM. A predominantly exfoliated structure was observed by TEM, which was confirmed by XDR analysis. The study demonstrated that the nanoclay increases the glass transition and crosslinking temperatures and also enhances the thermal stability of the coating.
The Influence of Melt and Process Parameters on the Quality and Occurrence of Part Defects in Water-assisted Injection Molded Tubes
Authors: Sannen S. , De Keyzer J. , Van Puyvelde P.
Published: November 2011

This study investigates the influence of melt and process parameters on the quality of water-assisted injection molded tubes. The influence was determined by the aid of a design of experiments (DOE) for both a HDPE and a PP resin. This design was carried out on two different cavities, in which the residual wall thickness (RWT) and the part weight were set as response functions. This was combined with a visual inspection of the part surface to detect correlations in the occurrence of part defects such as fingering and double wall. It was found that the water injection delay time and the water volume flow rate have the largest influence on the RWT and part weight. Moreover, the shear viscosity of the applied material determines the width and shape of the water bubble and consequently the RWT and part weight. In addition, process parameters such as melt temperature, water hold time and water volume flow rate as well as melt parameters such as shear viscosity have an influence on the formation of part defects.
Performance of Superpave Projects in Louisiana
Authors: Kabir Md Sharear , Icenogle Patrick , King William (Bill) , Abadie Christopher
Published: November 2011

The Louisiana Department of Transportation and Development (Louisiana DOTD) initiated the implementation of the Superpave® system by the end of the past decade. This study evaluated 8 to 10 years of field performance of 21 Louisiana Superpave projects, which included five Interstates, four U.S. routes, and 12 Louisiana routes. The evaluation was limited to the field performance of projects relative to age and did not consider factors associated with materials or construction. The criteria used to evaluate performance were confined to rutting, the international roughness index (IRI), alligator cracking, and random cracking. Superpave distress data were collected and stored in the pavement management system database of the Louisiana DOTD every 2 years. The collected data sets were analyzed and compared with Louisiana performance prediction models. These models were developed in the late 1990s by an expert panel from the Louisiana DOTD to predict the deterioration of pavement near the end of its design life. The original performance prediction models were reevaluated in 2002, and roughness models were implemented in 2003. The analysis indicated that after 8 to 10 years of service, most of the projects on Interstate and state highways were in good condition relative to the distress factors evaluated. Superpave seemed to control the early rutting and cracking in hot-mix construction while maintaining good IRI over the years. Points of concern, however, were the few issues of rutting on U.S. highways and cracking on Louisiana routes. In general, the rate of deterioration for rutting and IRI was lower than the prediction from the performance models.
Coarse Aggregate Angularity and Its Relationship to Permanent Deformation of Gravel-Aggregate Hot-Mix Asphalt in New York State
Authors: Bennert Thomas , Cooley L. Allen , Ericson Christopher , Zavery Zoeb
Published: November 2011

This study evaluated the asphalt mixture performance of various gravel and crushed stone sources with different levels of crushed face counts as determined by ASTM D5821. Coarse aggregate angularity and texture were also evaluated with AASHTO T326 and aggregate imaging system testing. Each of the asphalt mixtures designed and tested used three asphalt binders: (a) neat PG 64-22, (b) polymer-modified PG 64-22 meeting New York State Department of Transportation (New York State DOT) elastic recovery specifications, and (c) polymer-modified PG 76-22. The permanent deformation properties of the different asphalt mixtures were measured with the asphalt pavement analyzer (AASHTO TP63) and the asphalt mixture performance tester (AASHTO TP79) with confining pressure applied to the specimens. Aggregate testing showed that ASTM D5821 correlated poorly with both AASHTO T326 and the aggregate imaging system. Situations also occurred in which aggregates had identical crushed counts but different levels of uncompacted void contents. The asphalt mixture performance tester that used confining pressure correlated well with the uncompacted voids content results of AASHTO T326. However, stresses applied in the asphalt pavement analyzer did not sufficiently mobilize the asphalt mixtures to allow differences in aggregate angularity to be clearly noted. Both asphalt tests were sensitive to asphalt binder high-temperature stiffness as determined by AASHTO TP70. Statistical analysis of the data resulted in a table that allows the New York State DOT to use aggregate angularity (as determined by AASHTO T326) and nonrecoverable creep compliance (as determined by AASHTO TP70) interchangeably to ensure that hot-mix asphalt (HMA) blends containing gravel aggregate perform as well as HMA blends containing crushed-stone aggregate.
Alternate Shift Factor Relationship for Describing Temperature Dependency of Viscoelastic Behavior of Asphalt Materials
Authors: Rowe Geoffrey M. , Sharrock M. J.
Published: November 2011

Traditionally, various forms of shift factors such as Arrhenius, Williams–Landel–Ferry (WLF), and polynomials have been used with asphalt materials. Shift factors have also been estimated with binder viscosity parameters. Successful extrapolation of viscoelastic functions requires a robust form of shift factor–temperature relationship. This form is important for performing calculations at the extremes of temperature found in practice. A preliminary analysis of complex modulus E* data of mixtures obtained from the Mechanistic–Empirical Pavement Design Guide (MEPDG) database demonstrated that the Kaelble form of shift factor could describe the functional form of the shift factor more accurately than the Arrhenius, WLF, or polynomial-fitting functions. However, the Kaelble shift function as originally described uses the same temperature as a reference temperature and as an inflection temperature. This factor creates a problem when attempts are made to implement the function in a design method or when materials are compared at a given temperature. Since 2008, additional work has investigated the use of this shift function to describe the properties of asphalt materials, particularly mixes and materials that require a wide range of property description (both above and below the glass transition or some other defining point). A modified form of the Kaelble function has been implemented in analysis software and thus makes multiple calculations more rapid. Additional analysis working with MEPDG E* database materials has shown that shifting works best with the Kaelble modification of the WLF equation. The same method has been applied to other asphalt materials.
Practical Method to Understand the Effect of Aggregate Drying on the Moisture Content of Hot-Mix Asphalt
Authors: Mallick Rajib B. , Tao Mingjiang , Chen Bao-Liang , O'Sullivan Karen , Cacciatore Peter
Published: November 2011

The drying of aggregates is a critical step in obtaining moisture-free hotmix asphalt (HMA). The drying depends on many factors, which include the absorption and the moisture content of the aggregates as well as the drying temperature and time. The effect of drying of the aggregates on the moisture content of the resultant HMA needs to be understood so that adequate drying can be carried out for mixes, such as warm-mix asphalt (WMA), which are produced at lower than conventional temperatures. The objectives of this study were (a) to develop a laboratory method to produce HMA samples with various moisture contents that mimic insufficient drying of aggregates in a drum mixer and (b) to develop a nondestructive laboratory testing procedure to determine moisture content of compacted HMA samples. Aggregates with relatively high and low absorption rates were selected. A practical method was developed to mimic the retention of aggregate moisture in HMA in the laboratory. Good correlation was obtained between drying time and moisture-content loss for the aggregates of high and low water absorption. An experiment with heat transfer and a simulation with a finite element method confirmed the presence of moisture and its significant effect on the thermal conductivity of the mixes, which provided a nondestructive approach to determine moisture content of compacted HMA samples.
Cervical spinal stenosis and sports-related cervical cord neurapraxia
Authors: Clark Aaron J. , Auguste Kurtis I. , Sun Peter P.
Published: November 2011

Cervical cord neurapraxia is a common sports-related injury. It is defined as a transient neurological deficit following trauma localizing to the cervical spinal cord and can be caused by hyperextension, hyperflexion, or axial load mechanisms. Symptoms usually last less than 15 minutes, but can persist up to 48 hours in adults and as long as 5 days in children. While a strong causal relationship exists between cervical spine stenosis and cervical cord neurapraxia in adult patients, this association has not been observed in children. Likewise, while repeated episodes of neurapraxia can be commonplace in adult patients, recurrences have not been reported in the pediatric population. Treatment is usually supportive, but in adults with focal cervical lesions or instability, surgery is an option. Surgery for neurapraxia in children is rarely indicated.
Axillary nerve injury associated with sports
Authors: Lee Sangkook , Saetia Kriangsak , Saha Suparna , Kline David G. , Kim Daniel H.
Published: November 2011

Object

The aim of this retrospective study was to present and investigate axillary nerve injuries associated with sports.

Methods

This study retrospectively reviewed 26 axillary nerve injuries associated with sports between the years 1985 and 2010. Preoperative status of the axillary nerve was evaluated by using the Louisiana State University Health Science Center (LSUHSC) grading system published by the senior authors. Intraoperative nerve action potential recordings were performed to check nerve conduction and assess the possibility of resection. Neurolysis, suture, and nerve grafts were used for the surgical repair of the injured nerves. In 9 patients with partial loss of function and 3 with complete loss, neurolysis based on nerve action potential recordings was the primary treatment. Two patients with complete loss of function were treated with resection and suturing and 12 with resection and nerve grafting. The minimum follow-up period was 16 months (mean 20 months).

Results

The injuries were associated with the following sports: skiing (12 cases), football (5), rugby (2), baseball (2), ice hockey (2), soccer (1), weightlifting (1), and wrestling (1). Functional recovery was excellent. Neurolysis was performed in 9 cases, resulting in an average functional recovery of LSUHSC Grade 4.2. Recovery with graft repairs averaged LSUHSC Grade 3 or better in 11 of 12 cases

Conclusions

Surgical repair can restore useful deltoid function in patients with sports-associated axillary nerve injuries, even in cases of severe stretch–contusion injury.
Development of an iPhone application for sideline concussion testing
Authors: Curaudeau Guillaume A. , Sharma Nikhil , Rovin Richard A.
Published: November 2011

Professional athletes are taking concussion very seriously, and missed play due to concussion is no longer stigmatized. One fortuitous consequence is increased awareness of the detrimental effects of concussion among student athletes. Whereas professional athletes have access to formal in-competition evaluation and out-of-competition monitoring programs, the majority of student athletes, especially at the middle school and high school levels, do not. The authors therefore set out to create an easy-to-use iPhone application for sideline concussion testing and serial monitoring of these at-risk athletes.
Costs and benefits of neurosurgical intervention for infant hydrocephalus in sub-Saharan Africa
Authors: Warf Benjamin C. , Alkire Blake C. , Bhai Salman , Hughes Christopher , Schiff Steven J. , Vincent Jeffrey R. , Meara John G.
Published: November 2011

Object

Evidence from the CURE Children's Hospital of Uganda (CCHU) suggests that treatment for hydrocephalus in infants can be effective and sustainable in a developing country. This model has not been broadly supported or implemented due in part to the absence of data on the economic burden of disease or any assessment of the cost and benefit of treatment. The authors used economic modeling to estimate the annual cost and benefit of treating hydrocephalus in infants at CCHU. These results were then extrapolated to the potential economic impact of treating all cases of hydrocephalus in infants in sub-Saharan Africa (SSA).

Methods

The authors conducted a retrospective review of all children initially treated for hydrocephalus at CCHU via endoscopic third ventriculostomy or shunt placement in 2005. A combination of data and explicit assumptions was used to determine the number of times each procedure was performed, the cost of performing each procedure, the number of disability-adjusted life years (DALYs) averted with neurosurgical intervention, and the economic benefit of the treatment. For CCHU and SSA, the cost per DALY averted and the benefit-cost ratio of 1 year's treatment of hydrocephalus in infants were determined.

Results

In 2005, 297 patients (median age 4 months) were treated at CCHU. The total cost of neurosurgical intervention was $350,410, and the cost per DALY averted ranged from $59 to $126. The CCHU's economic benefit to Uganda was estimated to be between $3.1 million and $5.2 million using a human capital approach and $4.6 million–$188 million using a value of a statistical life (VSL) approach. The total economic benefit of treating the conservatively estimated 82,000 annual cases of hydrocephalus in infants in SSA ranged from $930 million to $1.6 billion using a human capital approach and $1.4 billion–$56 billion using a VSL approach. The minimum benefit-cost ratio of treating hydrocephalus in infants was estimated to be 7:1.

Conclusions

Untreated hydrocephalus in infants exacts an enormous price from SSA. The results of this study suggest that neurosurgical intervention has a cost/DALY averted comparable to other surgical interventions that have been evaluated, as well as a favorable benefit-cost ratio. The prevention and treatment of hydrocephalus in SSA should be recognized as a major public health priority.
Five-year survival and outcome of treatment for postinfectious hydrocephalus in Ugandan infants
Authors: Warf Benjamin C. , Dagi Ariella R. , Kaaya Brian Nsubuga , Schiff Steven J.
Published: November 2011

Object

Neonatal infection is the most common cause of infant hydrocephalus in Uganda. Postinfectious hydrocephalus (PIH) is often accompanied by primary brain injury from the original infection. Since 2001, ETV (with or without choroid plexus cauterization) has been our primary treatment for PIH. The long-term outcome in these children is unknown.

Methods

We studied the 5-year outcome in a cohort of 149 infants treated for PIH from 2001 to 2005 and who lived in 4 districts close to the hospital. Survival analysis was performed using the Kaplan-Meier method. Statistical significance was determined using the Fisher, Breslow, and log-rank tests.

Results

The patients' mean age at presentation was 9.5 months (median 3.0 months). Eighty-four patients (56.4%) were successfully treated without a shunt. Operative mortality was 1.2% for ETV and 4.4% for shunt placement (p = 0.3). Five-year survival was 72.8% in the non–shunt-treated group and 67.6% in the shunt-treated group, with no difference in survival (log rank p = 0.43, Breslow p = 0.46). Of 43 survivors assessed at 5–11 years, those with shunts had significantly worse functional outcomes (p = 0.003–0.035), probably reflecting treatment selection bias since those with the worst sequelae of ventriculitis were more likely to be treated with shunt placement.

Conclusions

Nearly one-third of treated infants died within 5 years, and at least one-third of the survivors were severely disabled. There was no survival advantage for non–shunt-treated patients at 5 years. A randomized trial of endoscopic third ventriculostomy versus shunt placement for treating PIH may be indicated. Public health measures that prevent these infections are urgently needed.
Evaluating the Children's Hospital of Alabama endoscopic third ventriculostomy experience using the Endoscopic Third Ventriculostomy Success Score: an external validation study
Authors: Naftel Robert P. , Reed Gavin T. , Kulkarni Abhaya V. , Wellons John C.
Published: November 2011

Object

Endoscopic third ventriculostomy (ETV) success is dependent on patient characteristics including age, origin of hydrocephalus, and history of shunt therapy. Using these factors, an Endoscopic Third Ventriculostomy Success Score (ETVSS) model was constructed to predict success of therapy. This study reports a single-institution experience with ETV and explores the ETVSS model validity.

Methods

A retrospective chart review identified 151 consecutive patients who underwent ETV at a pediatric hospital between August 1995 and December 2009. Of these 151, 136 patients had at least 6 months of clinical follow-up. Data concerning patient characteristics, operative characteristics, radiological findings, complications, and success of ETV were collected. The actual success rates were compared with those predicted by the ETVSS model.

Results

The actual success rate of ETV at 6 months was 68.4% (93 of 136 patients), which compared well to the predicted ETVSS of 76.5% ± 12.5% (± SD). The C-statistic was 0.74 (95% CI 0.65–0.83), suggesting that the ability of the ETVSS to discriminate failures from successes was good. Secondary ETV was found to have a hazard ratio for failure of 4.2 (95% CI 2.4–7.2) compared with primary ETV (p < 0.001). The complication rate was 9.3% with no deaths. At the first radiological follow-up, the increased size of ventricles had a hazard ratio for failure of 3.0 (95% CI 1.5–6.0) compared with patients in whom ventricle size either remained stable or decreased (p = 0.002).

Conclusions

The ETVSS closely predicts the actual success of ETV, fitting the statistical model well. Shortcomings of the model were identified in overestimating success in patients with ETVSS ≤ 70, which may be attributable to the poor success of secondary ETVs in the authors' patient population.
Definition and measurement of rider-intrinsic physical attributes influencing all-terrain vehicle safety
Authors: Mattei Tobias A. , Bond Brandon J. , Hafner John W. , Morris Martin J. , Travis Jennifer , Hannah Greg , Webster Jim , Lin Julian J.
Published: November 2011

Object

All-terrain vehicle (ATV) usage has grown tremendously over the years, reaching 9.5 million vehicles in use in 2007. Accompanying this growth has been a concomitant increase in rider morbidity (including traumatic brain and spine injuries) and death, especially in children. The purpose of this study was to define and measure, through field testing, those physical attributes intrinsic to riders, such as height, weight, and wingspan, which may have implications for ATV riders' safety.

Methods

Three field tests (J-hook, brake, and bump) were developed and performed to allow direct measurement of the lateral, longitudinal, and vertical dynamics in 5 riders of varying heights, weights, and wingspans. Two ATVs, a utility and a sport model, were tested for further comparisons. Data were acquired using a comprehensive data acquisition system attached to the ATVs. Assignment of individual rider/ATV test safety ratings and a rider/ATV Total Safety Rating were made from the results of these field tests.

Results

The J-hook test results demonstrated that larger rider wingspans positively influence ATV rider safety and mitigate against lateral instability. From the brake test it was determined that a 10-in (25.4-cm) longitudinal displacement, such as that experienced during a sharp deceleration, for a rider of any height or weight, breached the level of defined safety. As rider weight increased, displacement decreased. The bump test provided evidence that increased rider weight also mitigates against vertical displacement.

Conclusions

Individuals with light weights and small wingspans, such as those in the pediatric population, are under considerable risk of injury when operating an ATV due to lateral, longitudinal, and vertical operational instability.
Peroneal nerve injury associated with sports-related knee injury
Authors: Cho Dosang , Saetia Kriangsak , Lee Sangkook , Kline David G. , Kim Daniel H.
Published: November 2011

Object

This study analyzes 84 cases of peroneal nerve injuries associated with sports-related knee injuries and their surgical outcome and management.

Methods

The authors retrospectively reviewed the cases of peroneal nerve injury associated with sports between the years 1970 and 2010. Each patient was evaluated for injury mechanism, preoperative neurological status, electrophysiological studies, lesion type, and operative technique (neurolysis and graft repair). Preoperative status of injury was evaluated by using a grading system published by the senior authors. All lesions in continuity had intraoperative nerve action potential recordings.

Results

Eighty-four (approximately 18%) of 448 cases of peroneal nerve injury were found to be sports related, which included skiing (42 cases), football (23 cases), soccer (8 cases), basketball (6 cases), ice hockey (2 cases), track (2 cases) and volleyball (1 case). Of these 84 cases, 48 were identified as not having fracture/dislocation and 36 cases were identified with fracture/dislocation for surgical interventions. Good functional outcomes from graft repair of graft length < 6 cm (70%) and neurolysis (85%) in low-intensity peroneal nerve injuries associated with sports were obtained. Recovery from graft repair of graft length between 6 and 12 cm (43%) was good and measured between Grades 3 and 4. However, recovery from graft repair of graft length between 13 and 24 cm was obtained in only 25% of patients.

Conclusions

Traumatic knee-level peroneal nerve injury due to sports is usually associated with stretch/contusion, which more often requires graft repair. Graft length is the factor to be considered for the prognosis of nerve repair.
Zur Freizeitnutzung von Schweizer Wäldern: ihre Bedeutung für die regionale Ökonomie
Authors: Vogt Luisa , Pütz Marco
Published: November 2011

Recreational use of Swiss forests: their importance for the regional economy

Forests fulfill conservation, production and welfare functions. If forests are not considered isolatedly, but rather as part of a landscape or a region, their positive impact on regional welfare becomes apparent. The regional economic impact of the recreational use of Swiss forests is investigated in the case study regions of Sihlwald, a typical local recreation area, and Bergell, a destination for nature-based tourism. The relative importance of forests in the decision to visit the case study regions is identified by means of a conjoint analysis that assesses the forest affinity of visitors. Both the regional added value and the employment effects of the recreational use of forests are identified in an economic impact analysis. The results show that although they have a high affinity for forests, visitors to local recreation forests, such as the Sihlwald, spend little and generate rather small regional economic impacts. In contrast, the findings for nature-based tourism destinations, such as the Bergell, show a different picture: although the forest is not the most important criterion when selecting the destination, the regional economy benefits from higher consumer expenditures. The amount of visitor expenditure most notably depends on the variety and quality of tourism services in and around the forest area. Hence, to promote the regional economic importance of the recreational use of forests, tourism services in forest areas would have to be created or enhanced.
Warum Nachhaltigkeitsbeurteilungen Alternativen zu Kosten-Nutzen-Analysen erfordern
Authors: Hadorn Gertrude Hirsch , Allenspach Urs , Brun Georg
Published: November 2011

Why alternatives to cost-benefit analysis in sustainability assessments are necessary

Policies for sustainable forest management aim at maintaining forest ecosystems for sustainable development. Sustainable development as a societal mission comprises a diversity of factors that are neither hierarchically ordered nor freely compensable. Policies must therefore be assessed by a multidimensional criterion. Cost-benefit analysis provides a clear recommendation for a rational choice of policy. However, from a sustainability perspective, cost-benefit analysis has disadvantages, due to its methodological basis. Monetization and aggregation of preferences leave the reasons for measured preferences intransparent; trade-offs can occur arbitrarily; and it is not registered, whether and how critical limits of life support systems are affected. Avoiding these problems calls for assessment methods without aggregation or synthesising across heterogeneous standards. Dynamic decision theory provides ideas on how rational decisions can be taken based on a plurality of standards. The crucial ideas are prevention, precommitment, and a memory of past decisions. These can already be found in practice.
Oral ulceration at primary care-A Review
Authors: Ahmed MU , Uddin MN
Published: November 2011

Oral ulcers are common, with an estimated point prevalence of 4% in the world wide. Aphthous ulcers may affect as many as 25% of the population worldwide. Patients with an oral ulcer may present initially to a general practitioner or a dental practitioner. Most ulcers are benign and resolve spontaneously but a small proportion are malignant. The incidence and prevalence of oral cancer varies across the world. Some of the highest incidences are seen in the Indian subcontinent, southern France, and South America. Importantly, the incidence of oral cancer is rising in most populations, particularly in young women. In the United Kingdom, around 2500 cases of oral cavity cancers are seen every year.   Prevalence of oral lesions in population screening and survey studies shows that Candida-related and red-and­white lesions affect 47%, denture-related 8.4%, tobacco 4.7%, oral caratotic 3.4%, carcinoma or severe dysplasia  0.2%. DOI: http://dx.doi.org/10.3329/bdjps.v1i2.8802 BDJPS 2010; 1(2): 23-29
A teenage girl with extensive form of Hidradenitis suppurativa of sternal, submammary region and both axilla
Authors: Kalam MA , Rahman SA , Ahmad F , Akhter SMQ
Published: November 2011

Hidradenitis suppurativa is a rare non-contagious, chronic, relapsing suppurativa cicatrizing skin disease that most commonly affects areas of the body bearing apocrine sweat glands or sebaceous glands, such as the underarms,  breasts, inner thighs, groin and buttocks, which manifests itself as a clusters of chronic abscesses, sinus, fistulas  or multilocalised infections. This physically, psychologically, and socially disabling disease is extremely painful  to touch and may persist for years with occasional to frequent periods of inflammation, culminating in drainage,  often leaving open wounds that will not heal. As it is considered as a rare disease the incidence rate is not well known, but estimated in a range between 1:24(4.1%) and 1:600(0.2%) in which the post-pubertal females are more affected than males. The exact cause of hidradenitis suppurativa remains unclear. What is understood is  that the condition is a disorder of follicular occlusion. With genetic predisposition, obesity, hormonal influences  etc contribute to the causation of the disease .There is no cure for hidradenitis suppurativa. But early treatment can help to manage the symptoms and to prevent new lesions from developing. Long term antibiotics are the treatment of choice in early stage, but relapsing and recurrent cases may need surgical interventions. Here we present an 18 year old girl suffering from this disabling disease in both axillas, sternal and submammary region for six years. She was treated inadequately with oral antibiotics and surgical intervention in the form of incision and drainage done previously. We treated her with wide excision of the diseased skin and defect reconstructed with  local advancement flap. Histopathological study of the excised skin revealed Hidradenitis suppurativa.   Key word : Epidermis/surgery; vitiligo/therapy; transplantation alutologous DOI: http://dx.doi.org/10.3329/bdjps.v1i2.8803 BDJPS 2010; 1(2): 30-37
Korney Chukovsky in Britain
Authors: Vaninskaya Anna
Published: November 2011

Korney Chukovsky is a neglected figure in the story of the British reception of Russian literature. This essay attempts to recover his place in the complex networks of translation, criticism, and interpretation in the twentieth century by examining his three visits to Britain (1903-4, 1916, and 1962), his activities as an intermediary for British writers in Russia, and the British dissemination of his literary criticism.In his alternate guises as indigent newspaper correspondent, feted member of a wartime delegation, and recipient of an Oxford honorary doctorate, Chukovsky came to be both a key contributor to and a keen observer of British perceptions of Russian literature.