bluuebunny/crossref_metadata_2025 huggingface dataset:
Reduction of motion blurring artifacts using respiratory gated CT in sinogram space: A quantitative evaluation
Authors: Lu Wei , Parikh Parag J. , Hubenschmidt James P. , Politte David G. , Whiting Bruce R. , Bradley Jeffrey D. , Mutic Sasa , Low Daniel A.
Published: December 2005

Techniques have been developed for reducing motion blurring artifacts by using respiratory gated computed tomography (CT) in sinogram space and quantitatively evaluating the artifact reduction. A synthetic sinogram was built from multiple scans intercepting a respiratory gating window. A gated CT image was then reconstructed using the filtered back‐projection algorithm. Wedge phantoms, developed for quantifying the motion artifact reduction, were scanned while being moved using a computer‐controlled linear stage. The resulting artifacts appeared between the high and low density regions as an apparent feature with a Hounsfield value that was the average of the two regions. A CT profile through these regions was fit using two error functions, each modeling the partial‐volume averaging characteristics for the unmoving phantom. The motion artifact was quantified by determining the apparent distance between the two functions. The blurring artifact had a linear relationship with both the speed and the tangent of the wedge angles. When gating was employed, the blurring artifact was reduced systematically at the air‐phantom interface. The gated image of phantoms moving at showed similar blurring artifacts as the nongated image of phantoms moving at . Nine patients were also scanned using the synchronized respiratory motion technique. Image artifacts were evaluated in the diaphragm, where high contrast interfaces intercepted the imaging plane. For patients, this respiratory gating technique reduced the blurring artifacts by 9%–41% at the lung‐diaphragm interface.
AEC for scanning digital mammography based on variation of scan velocity
Authors: Åslund Magnus , Cederström Björn , Lundqvist Mats , Danielsson Mats
Published: December 2005

A theoretical evaluation of nonuniform x‐ray field distributions in mammography was conducted. An automatic exposure control (AEC) is proposed for a scanning full field digital mammography system. It uses information from the leading part of the detector to vary the scan velocity dynamically, thus creating a nonuniform x‐ray field in the scan direction. Nonuniform radiation fields were also created by numerically optimizing the scan velocity profile to each breast's transmission distribution, with constraints on velocity and acceleration. The goal of the proposed AEC is to produce constant pixel signal‐to‐noise ratio throughout the image. The target pixel SNR for each image could be set based on the breast thickness, breast composition, and the beam quality as to achieve the same contrast‐to‐noise ratio between images for structures of interest. The results are quantified in terms of reduction in entrance surface air kerma (ESAK) and scan time relative to a uniform x‐ray field. The theoretical evaluation was performed on a set of 266 mammograms. The performance of the different methods to create nonuniform fields decreased with increased detector width, from 18% to 11% in terms of ESAK reduction and from 30% to 25% in terms of scan time reduction for the proposed AEC and detector widths from . Some correlation was found between compressed breast thickness and the projected breast area onto the image field. This translated into an increase of the ESAK and decrease of the scan time reduction with breast thickness. Ideally a nonuniform field in two dimensions could reduce the entrance dose by 39% on average, whereas a field nonuniform in only the scanning dimension ideally yields a 20% reduction. A benefit with the proposed AEC is that the risk of underexposing the densest region of the breast can be virtually eliminated.
Monte Carlo and thermoluminescence dosimetry of the new model I25.S17 interstitial brachytherapy seed
Authors: Lymperopoulou G. , Papagiannis P. , Sakelliou L. , Karaiskos P. , Sandilos P. , Przykutta A. , Baltas D.
Published: December 2005

Monte Carlo simulation and experimental thermoluminescence dosimetry were utilized for the dosimetric characterization of the new model I25.S17 interstitial brachytherapy seed. The new seed design is similar to that of the selectSeed and 6711 seeds, with the exception of its molybdenum marker. Full dosimetric data are presented following the recommendations in the Update of the AAPM Task Group 43 report (TG‐43U1). A difference of 3.3% was found between Monte Carlo dose rate constant results calculated by air kerma strengths from simulations using a point detector and a detector resembling the solid angle subtended to the seed by the Wide Angle Free Air Chamber (WAFAC) in the primary standard calibration geometry. Following the TG‐43U1 recommendations, an average value of was adopted for the new seed. This value was then averaged with the measured value of to yield the proposed dose rate constant for the new seed that is equal to . The Monte Carlo calculated radial dose function and two‐dimensional (2‐D) anisotropy function results for the new seed were found in agreement with experimental results to within statistical uncertainty of repeated measurements. Monte Carlo simulations were also performed for seeds of similar geometry and dimensions for the purpose of comparison. The new seed presents dosimetric characteristics that are very similar to that of the selectSeed. In comparison to the most extensively studied Amersham 6711 seed, the new one presents similar dosimetric characteristics with a slightly reduced dose rate constant (1.5%).
Sampling size in the verification of manufactured‐supplied air kerma strengths
Authors: Ramos Luis Isaac , Martinez Monge Rafael
Published: December 2005

Quality control mandate that the air kerma strengths of permanent seeds be verified, this is usually done by statistics inferred from 10% of the seeds. The goal of this paper is to proposed a new sampling method in which the number of seeds to be measured will be set beforehand according to an a priori statistical level of uncertainty. The results are based on the assumption that the has a normal distribution. To demonstrate this, the of each of the seeds measured was corrected to ensure that the average of its sample remained the same. In this process 2030 results were collected and analyzed using a normal plot. In our opinion, the number of seeds sampled should be determined beforehand according to an a priori level of statistical uncertainty.
Effect of beamlet step‐size on IMRT plan quality
Authors: Zhang Guowei , Jiang Ziping , Shepard David , Earl Matt , Yu Cedric
Published: December 2005

We have studied the degree to which beamlet step‐size impacts the quality of intensity modulated radiation therapy (IMRT) treatment plans. Treatment planning for IMRT begins with the application of a grid that divides each beam's‐eye‐view of the target into a number of smaller beamlets (pencil beams) of radiation. The total dose is computed as a weighted sum of the dose delivered by the individual beamlets. The width of each beamlet is set to match the width of the corresponding leaf of the multileaf collimator (MLC). The length of each beamlet (beamlet step‐size) is parallel to the direction of leaf travel. The beamlet step‐size represents the minimum stepping distance of the leaves of the MLC and is typically predetermined by the treatment planning system. This selection imposes an artificial constraint because the leaves of the MLC and the jaws can both move continuously. Removing the constraint can potentially improve the IMRT plan quality. In this study, the optimized results were achieved using an aperture‐based inverse planning technique called direct aperture optimization (DAO). We have tested the relationship between pencil beam step‐size and plan quality using the American College of Radiology's IMRT test case. For this case, a series of IMRT treatment plans were produced using beamlet step‐sizes of 1, 2, 5, and . Continuous improvements were seen with each reduction in beamlet step size. The maximum dose to the planning target volume (PTV) was reduced from 134.7% to 121.5% and the mean dose to the organ at risk (OAR) was reduced from 38.5% to 28.2% as the beamlet step‐size was reduced from . The smaller pencil beam sizes also led to steeper dose gradients at the junction between the target and the critical structure with gradients of 6.0, 7.6, 8.7, and achieved for beamlet step sizes of 10, 5, 2, and , respectively.
Dose rate constant of a Cesium‐131 interstitial brachytherapy seed measured by thermoluminescent dosimetry and gamma‐ray spectrometry
Authors: Chen Z. , Bongiorni P. , Nath R.
Published: December 2005

The aim of this work was to conduct an independent determination of the dose rate constant of the newly introduced Model CS‐1 seed. A total of eight seeds were obtained from the seed manufacturer. The air‐kerma strength of each seed was measured by the manufacturer whose calibration is traceable to the air‐kerma strength standard established for the seeds at the National Institute of Standards and Technology ( uncertainty ). The dose rate constant of each seed was measured by two independent methods: One based on the actual photon energy spectrum emitted by the seed using gamma‐ray spectrometry and the other based on the dose‐rate measured by thermoluminescent dosimeter (TLD) in a Solid Water™ phantom. The dose rate constant in water determined by the gamma‐ray spectrometry technique and by the TLD dosimetry are and , respectively, showing excellent agreement with each other. These values, however, are approximately 15% greater than a previously reported value of [Med. Phys. 31, 1529–1538 (2004)]. Although low‐energy fluorescent x rays at 16.6 and 18.7 keV, originating from niobium present in the seed construction, were measured in the energy spectrum of the seeds, their yields were not sufficient to lower the dose rate constant to the value of . Additional determinations of the dose rate constant may be needed to establish an AAPM recommended consensus value for routine clinical use of the seed.
Tilted plane Feldkamp type reconstruction algorithm for spiral cone beam CT
Authors: Yan Ming , Zhang Cishen
Published: December 2005

An approximate image reconstruction method for spiral cone beam computed tomography (CT), called tilted plane Feldkamp type reconstruction algorithm (TPFR), is presented in this paper, which extends Feldkamp cone beam reconstruction algorithm to deal with its inaccuracy and artifact problems caused by large cone angle. This is done by tilting the reconstructing planes to minimize the cone angle and optimally fit the spiral segment of the source. The tilted plane image reconstruction requires reforming the three‐dimensional projection data set for the tilted plane and application of Feldkamp algorithm to the reformed data set. Analytical and computational results can show that the image reconstruction performance of the proposed TPFR algorithm is superior to that of the Feldkamp reconstruction algorithm in the image quality, volume coverage speed, maximum achievable pitch value, and slice sensitivity profiles. Moreover, it provides more accurate image reconstruction than the existing two‐dimensional reconstruction algorithms.
Matching and reconstruction of brachytherapy seeds using the Hungarian algorithm (MARSHAL)
Authors: Jain Ameet Kumar , Zhou Yu , Mustufa Tabish , Clif Burdette E. , Chirikjian Gregory S. , Fichtinger Gabor
Published: December 2005

Intraoperative dosimetric quality assurance in prostate brachytherapy critically depends on discerning the three‐dimensional (3D) locations of implanted seeds. The ability to reconstruct the implanted seeds intraoperatively will allow us to make immediate provisions for dosimetric deviations from the optimal implant plan. A method for seed reconstruction from segmented C‐arm fluoroscopy images is proposed. The 3D coordinates of the implanted seeds can be calculated upon resolving the correspondence of seeds in multiple x‐ray images. We formalize seed‐matching as a combinatorial optimization problem, which has salient features: (a) extensively studied solutions by the computer science community; (b) proof for the nonexistence of any polynomial time exact algorithm; and (c) a practical pseudo‐polynomial algorithm that mostly runs in time using any number of images. We prove that two images are insufficient to correctly match the seeds, while a third image renders the matching problem to be of nonpolynomial complexity. We utilize the special structure of the problem and propose a pseudopolynomial time algorithm. Using three presegmented images, matching and reconstruction of brachytherapy seeds using the Hungarian algorithm achieved complete matching in simulation experiments; and 98.5% in phantom experiments. 3D reconstruction error for correctly matched seeds has a mean of , and for incorrectly matched seeds. The maximum seed reconstruction error in each implant was typically around . Both on synthetic data and in phantom experiments, matching rate and reconstruction error achieved using presegmented images was found to be sufficient for prostate brachytherapy. The algorithm is extendable to deal with arbitrary number of images without any loss in speed or accuracy. The algorithm is sufficiently generic to provide a practical solution to any correspondence problem, across different imaging modalities and features.
On the automated definition of mobile target volumes from 4D‐CT images for stereotactic body radiotherapy
Authors: Zhang Tiezhi , Orton Nigel P. , Tomé Wolfgang A.
Published: December 2005

Stereotactic body radiotherapy (SBRT) can be used to treat small lesions in the chest. A vacuum‐based immobilization system is used in our clinic for SBRT, and a motion envelope is used in treatment planning. The purpose of this study is to automatically derive motion envelopes using deformable image registration of 4D‐CT images, and to assess the effect of abdominal pressure on the motion envelopes. 4D‐CT scans at ten phases were acquired prior to treatment for both free and restricted breathing using a vacuum‐based immobilization system that includes an abdominal pressure pillow. To study the stability of the motion envelope over the course of treatment, a mid‐treatment 4D‐CT scan was obtained after delivery of the third fraction for two patients. The planning target volume excluding breathing motion was defined on the image set at full exhalation phase and transformed into all other phases using displacement maps from deformable image registration. The motion envelope was obtained as the union of masks of all phases. The ratios of the motion envelope to volume ranged from 1.3 to 2.5. When pressure was applied, the ratios were reduced by as much as 29% compared to free breathing for some patients, but increased by up to 9% for others. The abdominal pressure pillow has more motion restriction effects on the anterior/inferior region of the lung. For one of the two patients for whom the 4D‐CT scan was repeated at mid‐treatment, the motion envelope was reproducible. However, for the other patient the tumor location and lung motion pattern significantly changed due to changes in the anatomy surrounding the tumor during the course of treatment, indicating that an image‐guided approach to SBRT may increase the efficacy of this treatment.
General relativity in the undergraduate physics curriculum
Authors: Hartle James B.
Published: December 2005

Einstein’s general relativity is increasingly important in contemporary physics on the frontiers of very large distance scales (astrophysics and cosmology) and very small length scales (elementary particle physics). This paper makes the case for a “physics first” approach to introducing general relativity to undergraduate physics majors.
Designing effective questions for classroom response system teaching
Authors: Beatty Ian D. , Gerace William J. , Leonard William J. , Dufresne Robert J.
Published: December 2005

Classroom response systems can be powerful tools for teaching physics. Their efficacy depends strongly on the quality of the questions. Creating effective questions is difficult and differs from creating exam and homework problems. Each classroom response system question should have an explicit pedagogic purpose consisting of a content goal, a process goal, and a metacognitive goal. Questions can be designed to fulfill their purpose through four complementary mechanisms: directing students' attention, stimulating specific cognitive processes, communicating information to the instructor and students via classroom response system-tabulated answer counts, and facilitating the articulation and confrontation of ideas. We identify several tactics that are useful for designing potent questions and present four “makeovers” to show how these tactics can be used to convert traditional physics questions into more powerful questions for a classroom response system.
Asymptotic relation between Darwin and mass-velocity one-electron molecular relativistic corrections
Authors: Diniz Leonardo G. , Mohallem José R.
Published: December 2005

We explore a relation suggested by the united-atom and separated-atom limits between the one-electron Darwin and mass-velocity relativistic contributions to the ground state molecular orbital of H2+.
The equivalence principle as a stepping stone from special to general relativity: A Socratic dialog
Authors: Drake S. P.
Published: December 2005

We show how students can be led to an understanding of the connection between special relativity and general relativity by considering the time dilation effect of clocks placed on the surface of the Earth. This paper is written as a Socratic dialog between a lecturer and a student.
Comparison of classical and second quantized description of the dynamic Stark shift
Authors: Haas M. , Jentschura U. D. , Keitel C. H.
Published: December 2005

We compare the derivation of the dynamic Stark shift of hydrogenic energy levels in a classical framework with an adiabatically damped laser-atom interaction, which is equivalent to the Gell-Mann-Low-Sucher formula, and a treatment based on time-independent perturbation theory, with a second-quantized laser-atom dipole interaction Hamiltonian. Our analysis applies to a laser that excites a two-photon transition in atomic hydrogen or in a hydrogenlike ion with low nuclear charge number. Our comparisons serve to demonstrate why the dynamic Stark shift may be interpreted as a stimulated radiative correction and illustrates connections between the two derivations. The simplest of the derivations is the fully quantized approach. The classical and the second-quantized treatment are shown to be equivalent in the limit of large photon numbers.
Exact and approximate energy spectrum for the finite square well and related potentials
Authors: de Alcantara Bonfim O. F. , Griffiths David J.
Published: December 2005

We investigate the problem of a quantum particle in a one-dimensional finite square well. In the standard approach the allowed energies are determined implicitly as the solutions to a transcendental equation. We obtain the spectrum analytically as the solution to a pair of parametric equations and algebraically using a remarkably accurate approximation to the cosine function. The approach is also applied to a variety of other quantum wells.
An undergraduate experiment to test relativistic kinematics using in flight positron annihilation
Authors: Dryzek Jerzy , Singleton Douglas , Suzuki Takenori , Yu Runsheng
Published: December 2005

The basic theoretical tenants of special relativity can be presented in introductory physics courses. However, because special relativistic effects only become apparent at velocities close to the speed of light, there are few experiments at the undergraduate level that involve special relativistic effects. We show that it is possible to experimentally verify the relation E2=p2c2+m02c4 in an undergraduate student laboratory using commercially available equipment. The experiment uses the annihilation of positrons in flight.
Metagenomics to Paleogenomics: Large-Scale Sequencing of Mammoth DNA
Authors: Poinar Hendrik N. , Schwarz Carsten , Qi Ji , Shapiro Beth , MacPhee Ross D. E. , Buigues Bernard , Tikhonov Alexei , Huson Daniel H. , Tomsho Lynn P. , Auch Alexander , Rampp Markus , Miller Webb , Schuster Stephan C.
Published: December 2005

We sequenced 28 million base pairs of DNA in a metagenomics approach, using a woolly mammoth (Mammuthus primigenius) sample from Siberia. As a result of exceptional sample preservation and the use of a recently developed emulsion polymerase chain reaction and pyrosequencing technique, 13 million base pairs (45.4%) of the sequencing reads were identified as mammoth DNA. Sequence identity between our data and African elephant (Loxodonta africana) was 98.55%, consistent with a paleontologically based divergence date of 5 to 6 million years. The sample includes a surprisingly small diversity of environmental DNAs. The high percentage of endogenous DNA recoverable from this single mammoth would allow for completion of its genome, unleashing the field of paleogenomics.
Graded associations between cardiorespiratory fitness, fatness, and blood pressure in children and adolescents
Authors: Klasson-Heggebø L , Andersen L B , Wennlöf A H , Sardinha L B , Harro M , Froberg K , Anderssen S A
Published: December 2005

Objective:To measure the graded relation between cardiorespiratory fitness and sum of skinfolds, waist circumference, and blood pressure in children and adolescents participating in the European youth heart study.

Methods:The participants were 4072 children and adolescents (aged 9 and 15) from Denmark, Portugal, Estonia, and Norway. Cardiorespiratory fitness was indirectly determined using a maximal ergometer cycle test. The sum of four skinfolds, waist circumference, and blood pressure were assessed with a standardised protocol. Linear regression analysis was used to test the graded relation between cardiorespiratory fitness and the dependent variables adjusted for pubertal stage, sex, and country.

Results:A significant curvilinear graded relation was found between cardiorespiratory fitness and waist circumference and sum of skinfolds (partialr2for cardiorespiratory fitness was 0.09–0.26 for the different sexes and age groups). Systolic and diastolic blood pressure also showed a curvilinear relation with cardiorespiratory fitness, and fitness explained 2% of the variance in systolic blood pressure. The difference in systolic blood pressure between the least and most fit was 6 mm Hg.

Conclusion:A curvilinear graded relation was found between cardiorespiratory fitness and waist circumference, sum of skinfolds, and systolic blood pressure. The greatest difference in these health variables was observed between low and moderate fitness levels.
Patellar taping does not change the amplitude of electromyographic activity of the vasti in a stair stepping task
Authors: Cowan S M , Hodges P W , Crossley K M , Bennell K L
Published: December 2005

Objectives:To investigate the effect of patellar taping on the amplitude of electromyographic activity (EMG) of vasti activation in subjects with and without patellofemoral pain (PFP).

Methods:Ten participants with PFP and 12 asymptomatic controls were recruited to the study. The study was designed as a randomised crossover trial. Participants completed a stair stepping task. Three experimental conditions were assessed: no tape, therapeutic medially directed tape, and placebo vertically directed tape. The main outcome measure was the EMG amplitude of the vastus medialis obliquus and vastus lateralis during the concentric phase of stair stepping.

Results:The application of medially directed therapeutic tape significantly decreased pain in subjects with PFP. However, application of tape over the patella (therapeutic or placebo) did not alter the amplitude of vasti EMG when either the PFP or control participants completed the concentric stair stepping task.

Conclusion:The results of this study indicate that the positive clinical effects of medially directed therapeutic tape are not due to changes in EMG amplitude of the vasti muscle. Thus other effects such as changes in timing of contraction of the vasti are more likely candidates for the mechanism of efficacy.
Angiogenic effect of intramuscular administration of basic and acidic fibroblast growth factor on skeletal muscles and influence of exercise on muscle angiogenesis
Authors: Efthimiadou A , Asimakopoulos B , Nikolettos N , Giatromanolaki A , Sivridis E , Papachristou D N , Kontoleon E
Published: December 2005

Background:Angiogenic factors which control the angiogenic process represent a promising strategy for restoration of blood flow, but require further evaluation before clinical use. Exercise has also been reported to induce neovascularisation in muscles.

Objectives:To evaluate the angiogenic effects of basic fibroblast growth factor (b-FGF) and acidic fibroblast growth factor (a-FGF) on rat gastrocnemius muscle, when administered intramuscularly, and to compare them with those obtained by daily exercise.

Methods:Forty nine rats were allotted to the following groups: A, controls; B, exercise by swimming; C1 and C2, intramuscular injection of b-FGF and a-FGF respectively; D1 and D2, b-FGF and a-FGF injection in combination with exercise. The antibody mouse anti-rat CD31 was used to evaluate the numbers of blood vessels present in histological preparations of gastrocnemius muscle.

Results:Significant increases in the numbers of blood vessels of the right gastrocnemius muscles in groups C1 and D1 were observed compared with controls (p<0.05). There was only a slight increase in angiogenesis in the left gastrocnemius muscle of groups C1 and D1 compared with controls (p>0.05), and there was a decrease in angiogenesis in the gastrocnemius muscle of the swimming group compared with controls.

Conclusion:The intramuscular administration of b-FGF, but not a-FGF, induced significant local angiogenesis in gastrocnemius muscle at the site of injection.
Type of acute hamstring strain affects flexibility, strength, and time to return to pre-injury level
Authors: Askling C , Saartok T , Thorstensson A
Published: December 2005

Objectives:To investigate possible links between aetiology of acute, first time hamstring strains in sprinters and dancers and recovery of flexibility, strength, and function as well as time to return to pre-injury level.

Methods:Eighteen elite sprinters and 15 professional dancers with a clinically diagnosed hamstring strain were included. They were clinically examined and tested two, 10, 21, and 42 days after the acute injury. Range of motion in hip flexion and isometric strength in knee flexion were measured. Self estimated and actual time to return to pre-injury level were recorded. Hamstring reinjuries were recorded during a two year follow up period.

Results:All the sprinters sustained their injuries during high speed sprinting, whereas all the dancers were injured while performing slow stretching type exercises. The initial loss of flexibility and strength was greater in sprinters than in dancers (p<0.05). At 42 days after injury, both groups could perform more than 90% of the test values of the uninjured leg. However, the actual times to return to pre-injury level of performance were significantly longer (median 16 weeks (range 6–50) for the sprinters and 50 weeks (range 30–76) for the dancers). Three reinjuries were noted, all in sprinters.

Conclusion:There appears to be a link between the aetiologies of the two types of acute hamstring strain in sprinters and dancers and the time to return to pre-injury level. Initially, sprinters have more severe functional deficits but recover more quickly.
Hip passive range of motion and frequency of radiographic hip osteoarthritis in former elite handball players
Authors: L’Hermette M , Polle G , Tourny-Chollet C , Dujardin F
Published: December 2005

Objective:To establish the relation between handball playing, passive hip range of motion (ROM), and the development of radiological hip osteoarthritis (OA) in former elite handball players. Two related issues are addressed: (a) the relation between long term elite handball playing and the incidence of hip OA; (b) the relations between hip ROM, OA, and pain.

Methods:Data on 20 former elite handball players and 39 control subjects were collected. A questionnaire yielded personal details, loading patterns during physical activity, and previous lower limb joint injury. Bilateral radiographs were analysed to diagnose and classify hip OA. Passive hip ROM was measured bilaterally with a goniometer.

Results:A close relation was found between long term elite handball practice and the incidence of hip OA: 60% of the handball players were diagnosed with OA in at least one of the hip joints compared with 13% of the control subjects. Passive ROM measured in the handball players was significantly lower for hip flexion and medial rotation and higher for abduction, extension, and lateral rotation than the control values. The handball players with OA reported less pain in the hip joints during daily activities than the control subjects with OA.

Conclusion:The risk of developing premature hip OA seems high for retired handball players and significantly greater than for the general population. Pain and discomfort represent two difficult diagnostic challenges to the sports physician, as the repetitive nature of movements that are specific to handball can lead to alterations that are rarely seen in the general population.
Concussion management by primary care providers
Authors: Pleacher M D , Dexter W W
Published: December 2005

Objective:To assess current concussion management practices of primary care providers.

Methods:An 11 item questionnaire was mailed to primary care providers in the state of Maine, with serial mailings to non-respondents.

Results:Over 50% of the questionnaires were completed, with nearly 70% of primary care providers indicating that they routinely use published guidelines as a tool in managing patients with concussion. Nearly two thirds of providers were aware that neuropsychological tests could be used, but only 16% had access to such tests within a week of injury.

Conclusions:Primary care providers are using published concussion management guidelines with high frequency, but many are unable to access neuropsychological testing when it is required.
Effects of long term Tai Chi practice and jogging exercise on muscle strength and endurance in older people
Authors: Xu D Q , Li J X , Hong Y
Published: December 2005

Objectives:To investigate the influence of regular Tai Chi (TC) practice and jogging on muscle strength and endurance in the lower extremities of older people.

Methods:Twenty one long term older TC practitioners were compared with 18 regular older joggers and 22 sedentary counterparts. Maximum concentric strength of knee flexors and extensors was tested at angular velocities of 30°/s and 120°/s. Ankle dorsiflexors and plantar flexors were tested at 30°/s and the dynamic endurance of the knee flexors and extensors was assessed at a speed of 180°/s.

Results:The differences in the muscle strength of the knee joint amongst the three experimental groups were significant at the higher velocity. The strengths of knee extensors and flexors in the control group were significantly lower than those in the jogging group and marginally lower than those in the TC group. For the ankle joint, the subjects in both the TC and jogging groups generated more torque in their ankle dorsiflexors. In addition, the muscle endurance of knee extensors was more pronounced in TC practitioners than in controls.

Conclusion:Regular older TC practitioners and joggers showed better scores than the sedentary controls on most muscle strength and endurance measures. However, the magnitude of the exercise effects on muscles might depend on the characteristics of different types of exercise.
Does complete deficiency of muscle α actinin 3 alter functional capacity in elderly women? A preliminary report: Table 1
Authors: San Juan A F , Gomez-Gallego F , Cañete S , Santiago C , Pérez M , Lucia A
Published: December 2005

The sarcomeric protein α actinin 3 is localised to the Z line of fast fibres, which are responsible for generating forceful muscle contractions at high velocity. However, a substantial proportion of healthy humans are totally deficient in this protein as they are homozygous for a premature stop codon polymorphism (R577X) in theACTN3gene. The purpose of this preliminary study was to assess if the presence or absence of α actinin 3 influences the deleterious effects of ageing on muscle output and functional capacity.
Acute weight loss followed by an aggressive nutritional recovery strategy has little impact on on-water rowing performance
Authors: Slater G , Rice A J , Tanner R , Sharpe K , Gore C J , Jenkins D G , Hahn A G
Published: December 2005

Objectives:To assess the influence of moderate, acute weight loss on on-water rowing performance when aggressive nutritional recovery strategies were used in the two hours between weigh in and racing.

Methods:Competitive rowers (n  =  17) undertook three on-water 1800 m time trials under cool conditions (mean (SD) temperature 8.4 (2.0)°C), each separated by 48 hours. No weight limit was imposed for the first time trial—that is, unrestricted body mass (UNR1). However, one of the remaining two trials followed a 4% loss in body mass in the previous 24 hours (WT−4%). No weight limit was imposed for the other trial (UNR2). Aggressive nutritional recovery strategies (WT−4%, 2.3 g/kg carbohydrate, 34 mg/kg Na+, and 28.4 ml/kg fluid; UNR, ad libitum) were used in the first 90 minutes of the two hours between weigh in and performance trials.

Results:WT−4%had only a small and statistically non-significant effect on the on-water time trial performance (mean 1.0 second, 95% confidence interval (CI) −0.9 to 2.8; p  =  0.29) compared with UNR. This was despite a significant decrease in plasma volume at the time of weigh in for WT−4%compared with UNR (−9.2%, 95% CI −12.8% to −5.6%; p<0.001).

Conclusions:Acute weight loss of up to 4% over 24 hours, when combined with aggressive nutritional recovery strategies, can be undertaken with minimal impact on on-water rowing performance, at least in cool conditions.
Cardiocirculatory and metabolic responses at different walking intensities
Authors: Schwarz M , Urhausen A , Schwarz L , Meyer T , Kindermann W
Published: December 2005

Objectives:Although walking is a common physical activity, scientifically based training guidelines using standardised tests have not been established. Therefore this explorative study investigated the cardiovascular and metabolic load resulting from different walking intensities derived from maximal velocity (Vmax) during an incremental treadmill walking test.

Methods:Oxygen uptake, heart rate (HR), blood concentrations of lactate and catecholamines, and rating of perceived exertion were recorded in 16 recreational athletes (mean (SD) age 53 (9) years) during three 30 minute walking trials at 70%, 80%, and 90% of Vmax(V70, V80, and V90) attained during an incremental treadmill walking test.

Results:Mean (SD) oxygen uptake was 18.2 (2.3), 22.3 (3.1), and 29.3 (5.0) ml/min/kg at V70, V80, and V90respectively (p<0.001). V70led to a mean HR of 110 (9) beats/min (66% HRmax), V80to 124 (9) beats/min (75% HRmax), and V90to 152 (13) beats/min (93% HRmax) (p<0.001). Mean (SD) lactate concentrations were 1.1 (0.2), 1.8 (0.6), and 3.9 (2.0) mmol/l at V70, V80, and V90respectively (p<0.001). There were no significant differences between catecholamine concentrations at the different intensities. Rating of perceived exertion was 10 (2) at V70, 12 (2) at V80, and 15 (2) at V90. Twelve subjects reported muscular complaints during exercise at V90but not at V70and V80.

Conclusions:Intensity and heart rate prescriptions for walking training can be derived from an incremental treadmill walking test. The cardiovascular and metabolic reactions observed suggest that V80is the most efficient workload for training in recreational athletes. Further studies are needed to confirm these findings.
Cervical spinal injury in children’s community rugby football
Authors: Browne G J
Published: December 2005

Objective:To examine the characteristics of cervical spinal injury (CSI) in school aged children injured in community based rugby football who presented to the emergency department for assessment.

Methods:This is a retrospective descriptive case series study reviewing the medical records of all children younger than 15 years of age who presented to the emergency department at the Children’s Hospital at Westmead, Sydney, Australia for assessment of injury to the cervical spine between 2000 and 2003.

Results:There were 125 children with CSI; most (97%) were boys of mean age 12.7 years. Injuries occurred throughout the season, with an unexpected peak in June. Neck pain was the main presenting complaint (98%). Neurological symptoms were reported in 43%, half having concussion. Hyperextension of the neck accounted for a third of all cases and was usually the result of a spear tackle. Appropriate treatment of the cervical spine on the field of play before transport to hospital was inconsistently performed. Half of the players with CSI suffered secondary injuries, consisting of concussive head injury, faciomaxillary injury, eye injury, or limb fracture. Admission to hospital was common, with all children admitted undergoing further radiological assessment. Two minor fractures were reported and no permanent neurological disability. Overall, no adverse events were reported and the clinical outcome was good.

Conclusion:CSI in children playing rugby football is rarely catastrophic although often associated with other injuries. Continued efforts are needed to educate players and referees to prevent injury.
A controlled clinical pilot trial to study the effectiveness of ice as a supplement to the exercise programme for the management of lateral elbow tendinopathy
Authors: Manias P , Stasinopoulos D
Published: December 2005

Background:The use of ice as a supplement to an exercise programme has been recommended for the management of lateral elbow tendinopathy (LET). No studies have examined its effectiveness.

Objectives:To investigate whether an exercise programme supplemented with ice is more successful than the exercise programme alone in treating patients with LET.

Methods:Patients with unilateral LET for at least four weeks were included in this pilot study. They were sequentially allocated to receive five times a week for four weeks either an exercise programme with ice or the exercise programme alone. The exercise programme consisted of slow progressive eccentric exercises of wrist extensors and static stretching of the extensor carpi radialis brevis tendon. In the exercise programme/ice group, the ice was applied after the exercise programme for 10 minutes in the form of an ice bag to the facet of the lateral epicondyle. Patients were evaluated at baseline, at the end of treatment, and three months after the end of treatment. Outcome measures used were the pain visual analogue scale and the dropout rate.

Results:Forty patients met the inclusion criteria. At the end of treatment there was a decline in visual analogue scale of about 7 units in both groups compared with baseline (p<0.0005, pairedttest). There were no significant differences in the magnitude of reduction between the groups at the end of treatment and at the three month follow up (p<0.0005, independentttest). There were no dropouts.

Conclusions:An exercise programme consisting of eccentric and static stretching exercises had reduced the pain in patients with LET at the end of the treatment and at the follow up whether or not ice was included. Further research to establish the relative, absolute, and cost effectiveness as well as the mechanism of action of the exercise programme is needed.
APPLICATIONS OF SUPPORT VECTOR MACHINES TO CANCER CLASSIFICATION WITH MICROARRAY DATA
Authors: CHU FENG , WANG LIPO
Published: December 2005

Microarray gene expression data usually have a large number of dimensions, e.g., over ten thousand genes, and a small number of samples, e.g., a few tens of patients. In this paper, we use the support vector machine (SVM) for cancer classification with microarray data. Dimensionality reduction methods, such as principal components analysis (PCA), class-separability measure, Fisher ratio, and t-test, are used for gene selection. A voting scheme is then employed to do multi-group classification by k(k - 1) binary SVMs. We are able to obtain the same classification accuracy but with much fewer features compared to other published results.
FAST TIME DELAY NEURAL NETWORKS
Authors: EL-BAKRY HAZEM M. , ZHAO QIANGFU
Published: December 2005

This paper presents a new approach to speed up the operation of time delay neural networks. The entire data are collected together in a long vector and then tested as a one input pattern. The proposed fast time delay neural networks (FTDNNs) use cross correlation in the frequency domain between the tested data and the input weights of neural networks. It is proved mathematically and practically that the number of computation steps required for the presented time delay neural networks is less than that needed by conventional time delay neural networks (CTDNNs). Simulation results using MATLAB confirm the theoretical computations.
A MODIFIED ERROR BACKPROPAGATION ALGORITHM FOR COMPLEX-VALUE NEURAL NETWORKS
Authors: CHEN XIAOMING , TANG ZHENG , VARIAPPAN CATHERINE , LI SONGSONG , OKADA TOSHIMI
Published: December 2005

The complex-valued backpropagation algorithm has been widely used in fields of dealing with telecommunications, speech recognition and image processing with Fourier transformation. However, the local minima problem usually occurs in the process of learning. To solve this problem and to speed up the learning process, we propose a modified error function by adding a term to the conventional error function, which is corresponding to the hidden layer error. The simulation results show that the proposed algorithm is capable of preventing the learning from sticking into the local minima and of speeding up the learning.
AN IMPROVED GENETIC ALGORITHM BASED FUZZY-TUNED NEURAL NETWORK
Authors: LING S. H. , LEUNG F. H. F. , LAM H. K.
Published: December 2005

This paper presents a fuzzy-tuned neural network, which is trained by an improved genetic algorithm (GA). The fuzzy-tuned neural network consists of a neural-fuzzy network and a modified neural network. In the modified neural network, a neuron model with two activation functions is used so that the degree of freedom of the network function can be increased. The neural-fuzzy network governs some of the parameters of the neuron model. It will be shown that the performance of the proposed fuzzy-tuned neural network is better than that of the traditional neural network with a similar number of parameters. An improved GA is proposed to train the parameters of the proposed network. Sets of improved genetic operations are presented. The performance of the improved GA will be shown to be better than that of the traditional GA. Some application examples are given to illustrate the merits of the proposed neural network and the improved GA.
A BIOGRAPHICAL STUDY OF ISAMBARD KINGDOM BRUNEL AS INSIGHT INTO ENTREPRENEURIAL MARKETING ENDEAVOUR
Authors: FILLIS IAN , HERMAN RUTH
Published: December 2005

This paper focuses on a biographical approach to entrepreneurial marketing research. Conventional research methodologies such as in-depth interview and questionnaires have a range of advantages, disadvantages and bias. Biographical research can result in the generation of longitudinal data which can be triangulated with data and theory from these more conventional approaches in order to enhance understanding of entrepreneurial marketing behaviour. In marketing, formal prescriptions of stepwise, linear processes dominate and in entrepreneurship the focus is often on new venture formation rather than in growing the firm. Previous research by the authors has focused on the creativity of individuals, groups and organisations using a combination of conventional research methods and the biographical approach. The paper builds on this research by investigating the entrepreneurial marketing endeavour of perhaps the best known British engineer, Isambard Kingdom Brunel. Although Brunel was first and foremost an engineer he was also a shrewd business person who demonstrated understanding of entrepreneurial marketing procedures. Comparing the findings with previous research results, it can be seen that a set of core entrepreneurial marketing constructs hold true over long periods of time. These factors can then be taken into consideration when developing more creative, entrepreneurial marketing theory for the firm.
ENTERPRISING WOMEN: GENDER AND MATURITY IN NEW VENTURE CREATION AND DEVELOPMENT
Authors: MOULT SUSAN , ANDERSON ALISTAIR R.
Published: December 2005

This study examines the role that gender played in the entrepreneurial actions of mature women in the process of starting and developing their businesses. The literature indicates that the characteristics of entrepreneuse and their businesses can be usefully categorised in terms of push and pull factors. Motivational pull factors are seen as broadly universal, fitting both men and women, but push factors, such as flexibility to accommodate domestic roles are presented as more important for women, Consequently our study examines mature entrepreneuse, who might be expected to have reduced domestic responsibilities. A sample of ten mature female entrepreneurs was selected because the literature indicated that there were specific "windows of entrepreneurial opportunity" in women's life stages. Such a window of opportunity could be expected to open when the demands of childrearing reduce as children become older. The respondents were interviewed in depth to explore the ramifications of gender in the motivation, expectations, purpose, action and outcomes of their business activities. We found that gender, in particular gender expectations, continued to play a significant configuring role in the way that these respondents operated their businesses.
RELIABILITY MODELING AND ANALYSIS OF COMPLEX HIERARCHICAL SYSTEMS
Authors: XING LIUDONG
Published: December 2005

In this paper we consider the problem of reliability modeling and analysis of hierarchical computer-based systems (HS) with modular imperfect coverage (MIPC) and common-cause failures (CCF). The MIPC and CCF can cause vertical dependence that runs through different levels of the system as well as horizontal dependence that runs across components or modules on the same system level. The consideration of these dependencies poses unique challenges to existing HS reliability analysis methods. We propose an efficient decomposition and aggregation approach named EDA-HS to the reliability evaluation of complex hierarchical systems with both MIPC and CCF as one way to meet the above challenges in an efficient and elegant manner. Our approach is to decouple the effects of both MIPC and CCF from the combinatorics of the solution. The approach is represented in a dynamic fault tree by a proposed probabilistic functional dependency gate and a proposed CCF gate modeled after the existing FDEP gate. We present the basics and advantages of the EDA-HS approach by working through an analysis of an example HS subject to MIPC and CCF.