bluuebunny/crossref_metadata_2025 huggingface dataset:
Learning Advanced Leadership
Authors: Orr Margaret Terry
Published: June 2007

Given the lack of preparation incoming school district superintendents receive and the many challenges they face, this article reviews the approach of the few existing programs for new superintendents and describes the leadership development strategies that would be beneficial. With this background, the article presents the findings from an evaluation of the New Superintendents Seminar Series, a pilot program created and managed by a major research university. Over a single calendar year the New Superintendents Seminar Series provided five weekend sessions and a week-long summer institute to six participants with less than three years of experience as superintendents. The series created learner-centered, action-oriented and reflection-rich learning strategies to develop self-directed learning, peer-mediated learning and engagement with experts. An action research evaluation demonstrated that, in general, the program faculty observed and the participants rated the series high as a learning experience and as a means for developing their leadership capabilities. They also reported that the series had an important impact on their approach to leadership and concrete work in their districts.
The First 100 Days
Authors: Sarros Anne M. , Sarros James C.
Published: June 2007

The first 100 days of a new senior executive appointment are fraught with multi-faceted challenges that rely on specific leadership approaches for their resolution. The purpose of this article is to (1) explore which leadership issues and initiatives most present themselves in the first 100 days of such an appointment, (2) examine the extent to which each dimension of the transformational-transactional leadership model manifests itself in the first 100 days of a new senior executive appointment in response to these issues, and (3) enhance the transformational model by examining it in terms of instructional leadership and three meta-dimensions, namely mission-centred, performance-centred and culture-centred leadership in relation to the key issues. Recommendations for replication of the study in different work environments and for practice are provided.
Managing Chronic Excuse-making Behaviors of Faculty
Authors: Burke Lisa A. , Rau Barbara
Published: June 2007

Managing chronic excuse-making behaviors of faculty can be difficult and challenging for college administrators. In this article, Schlenker's responsibility triangle is applied in the higher education forum to better understand the underpinnings of responsibility and accountability in faculty jobs. Using this framework, attention is given to strategies for preventing excuses from becoming a chronic and unwanted behavior for faculty to use when justifying performance shortcomings.
citizenship and the assessment of trainees
Authors: Davies Ian , Arthur James , Fairbrass Stephen , Mountford Paula , Revell Lynn , West Liz
Published: June 2007

This article is concerned with assessment of those in England training to become citizenship secondary teachers. We sketch the background to initial teacher education for secondary citizenship education, outline the methods of an empirical project on assessment of trainees and draw attention to emerging issues. We describe practice in selection, assessment of written assignments and assessment of teaching. We discuss issues relating to the provision of explicit experience of citizenship education for trainees in schools, the attempts that are being made to develop integrated and progressive approaches to assessment and the nature of the balance between specific and generic matters in the assessment of citizenship in ITT. Assessment of citizenship trainees is undertaken without serious controversy, is reliant on generic ITT practices and somewhat distinct from what one might expect given the expansive rhetoric about citizenship education.
now what?
Authors: Doppen Frans H.
Published: June 2007

The influx of Muslim immigrants in the Netherlands during the past 50 years and terrorist events in recent years have led to increased alienation. This case study, conducted at a culturally diverse school with a large Muslim student population, found that its administrators and `social studies' teachers agreed it is important to simultaneously teach students democratic values and help them to develop a sense of Dutch identity. Nearly all `social studies' teachers in this study indicated that the content of their courses was primarily determined by the national curriculum. Although they suggested that the changed student population did not and should have any significant impact on their curriculum, they nonetheless thought it was important to foster an understanding between non-Muslim and Muslim students. As the Netherlands has begun to rethink its civic curriculum, its schools must decide how to best prepare all students for living in an increasingly multicultural democratic society.
Physiological and morphological responses to feeding in broad-nosed caiman (Caiman latirostris)
Authors: Starck J. Matthias , Cruz-Neto Ariovaldo P. , Abe Augusto Shinya
Published: June 2007

Broad nosed caiman are ectotherm sauropsids that naturally experience long fasting intervals. We have studied the postprandial responses by measuring oxygen consumption using respirometry, the size changes of the duodenum, the distal small intestine, and the liver, using repeated non-invasive ultrasonography, and by investigating structural changes on the level of tissues and cells by using light- and electron microscopy. The caimans showed the same rapid and reversible changes of organ size and identical histological features, down to the ultrastructure level, as previously described for other ectothermic sauropsids. We found a configuration change of the mucosa epithelium from pseudostratified during fasting to single layered during digestion, in association with hypertrophy of enterocytes by loading them with lipid droplets. Similar patterns were also found for the hepatocytes of the liver. By placing the results of our study in comparative relationship and by utilizing the phylogenetic bracket of crocodiles, birds and squamates, we suggest that the observed features are plesiomorphic characters of sauropsids. By extending the comparison to anurans, we suggest that morphological and physiological adjustments to feeding and fasting described here may have been a character of early tetrapods. In conclusion, we suggest that the ability to tolerate long fasting intervals and then swallow a single large meal as described for many sit-an-wait foraging sauropsids is a functional feature that was already present in ancestral tetrapods.
The co-activation of snapshot memories in wood ants
Authors: Graham Paul , Durier Virginie , Collett Thomas
Published: June 2007

Insects can guide themselves along a familiar route to a familiar place by retrieving and using visual snapshots that they have stored both along the route and at their destination and moving so that their current views match the target snapshots. To learn more about the matching process, we have investigated the interaction of snapshots by engineering a situation in which ants simultaneously retrieve two sets of memories.

Ants were trained from a fixed start position to feed in one site, after which the feeder was switched to a new one. It could take up to 30 trials after the switch before the ants headed directly to the new food site. We suppose that during this transition phase ants retrieve memories appropriate for both sites. We compared the ants' behaviour for two different sized separations between feeder sites. When the sites are relatively close together, the initial headings of the ants' paths rotated gradually from aiming directly at the first food site to aiming at the second food site,suggesting that ants' paths are controlled by the weighted average of two simultaneously activated snapshot attractors. By contrast, when the food sites were further apart, initial headings switched abruptly between the two sites– ants either headed for food site 1 or for food site 2. We show that these differences in transition behaviour can be simulated by the co-activation of snapshot attractors of restricted spatial extent, such that features encoded in a snapshot are only recognised if they occur within a limited retinal distance of the stored position of the feature.
Reproductive success in two species of desert fleas: density dependence and host effect
Authors: Khokhlova Irina S. , Hovhanyan Anna , Krasnov Boris R. , Degen A. Allan
Published: June 2007

We tested the hypothesis that a negative fitness–density relationship exists in haematophagous ectoparasites. We studied the effect of flea density on the number of blood meals necessary for starting oviposition and egg production in Xenopsylla conformis and Xenopsylla ramesiswhen exploiting two rodent hosts, Meriones crassus and Gerbillus dasyurus. The number of blood meals taken by a flea prior to first oviposition was similar in both flea species but was dependent on flea density and differed significantly between hosts. When parasitizing G. dasyurus, females of both flea species required a similar number of blood meals to start oviposition, independent of density. By contrast, fleas on M. crassus at higher densities needed less blood meals than at lower densities. Egg production of female fleas differed significantly between flea and host species and was affected by flea density. X. ramesisproduced more eggs than X. conformis. When parasitizing G. dasyurus, density did not affect the number of eggs produced by X. conformis, however, when on M. crassus, this flea produced significantly less eggs at the highest density. The number of eggs produced by X. ramesis at high densities was significantly lower than at low densities when it parasitized either host species. Results of this study demonstrated that reproductive success of fleas was density dependent and, in general, decreased with an increase in density. However, the effect of density on reproductive performance was manifested differently on different host species.
Myoglobin-enhanced oxygen delivery to isolated cardiac mitochondria
Authors: Wittenberg Jonathan B. , Wittenberg Beatrice A.
Published: June 2007

The heart, red skeletal muscles and the nitrogen-fixing legume root nodule function in steady states of high oxygen influx, partial oxygenation of cytoplasmic myoglobin or leghemoglobin and correspondingly low oxygen partial pressure. Here, we ask: what conditions are required at the surface of actively respiring, state III, tightly coupled mitochondria to enhance oxygen flow to cytochrome oxidase? Pigeon heart mitochondria were isolated with minimal damage to the outer mitochondrial membrane and were incubated at low oxygen pressures, where respiration is oxygen limited, with solutions of each of six monomeric hemoglobins with widely divergent kinetics and equilibria in their reactions with oxygen: Busycon myoglobin, horse myoglobin, Lucina hemoglobins I and II, soybean leghemoglobin c and Gasterophilus hemoglobin. Each augments oxygen uptake. The declining fractional saturation of each hemoglobin with oxygen was monitored spectrophotometrically as mitochondrial respiration depleted the oxygen; the oxygen partial pressure at half-maximal rate of oxygen uptake was similar for each hemoglobin, supporting the conclusion that the hemoglobins did not interact with the mitochondrial surface in oxygen delivery. The oxygen pressure required to support state III mitochondrial oxygen uptake, 0.005 kPa (0.04 torr), is small compared with that obtained in the sarcoplasm and at the mitochondrial surface of the working heart, 0.32 kPa (2.4 torr). We conclude that, in normal steady states of contraction of the myoglobin-containing heart, oxygen utilization by mitochondrial cytochrome oxidase is not limited by oxygen availability.
Are ontogenetic shifts in diet linked to shifts in feeding mechanics?Scaling of the feeding apparatus in the banded watersnakeNerodia fasciata
Authors: Vincent Shawn E. , Moon Brad R. , Herrel Anthony , Kley Nathan J.
Published: June 2007

The effects of size on animal behaviour, ecology, and physiology are widespread. Theoretical models have been developed to predict how animal form,function, and performance should change with increasing size. Yet, numerous animals undergo dramatic shifts in ecology (e.g. habitat use, diet) that may directly influence the functioning and presumably the scaling of the musculoskeletal system. For example, previous studies have shown that banded watersnakes (Nerodia fasciata) switch from fish prey as juveniles to frog prey as adults, and that fish and frogs represent functionally distinct prey types to watersnakes. We therefore tested whether this ontogenetic shift in diet was coupled to changes in the scaling patterns of the cranial musculoskeletal system in an ontogenetic size series (70–600 mm snout–vent length) of banded watersnakes. We found that all cranial bones and gape size exhibited significant negative allometry, whereas the muscle physiological cross-sectional area (pCSAs) scaled either isometrically or with positive allometry against snout–vent length. By contrast, we found that gape size, most cranial bones, and muscle pCSAs exhibited highly significant positive allometry against head length. Furthermore, the mechanical advantage of the jaw-closing lever system remained constant over ontogeny. Overall, these cranial allometries should enable watersnakes to meet the functional requirements of switching from fusiform fish to bulky frog prey. However, recent studies have reported highly similar allometries in a wide diversity of vertebrate taxa, suggesting that positive allometry within the cranial musculoskeletal system may actually be a general characteristic of vertebrates.
Assessment of the pressure–volume relationship of the single ventricle of the grass shrimp, Palaemonetes pugio
Authors: Guadagnoli J. A. , Tobita K. , Reiber C. L.
Published: June 2007

The ventricular pressure–volume (PV) relationship has been used extensively to study the mechanics and energetics in multi-chambered hearts of closed circulatory system vertebrates. In the current study we applied the use of PV loops in the assessment of cardiac mechanics and energetics in the single ventricle of a decapod crustacean possessing an open circulatory system. Anatomical differences between multi-and single-chambered hearts include multiple ostia entering and valved multiple arterial systems exiting the ventricle, and the neurogenic origin of the heartbeat in decapod crustaceans. However, the microscopic architecture and excitation–contraction coupling events are similar in both systems. Ventricular pressure and area were obtained independently and integrated into pressure–area loops. Area was then converted to volume to generate PV loops. Based on the PV loops generated in this study, the ventricle of Palaemonetes pugio processes the same primary phases of the cardiac cycle as ventricles from the multi-chambered hearts of vertebrates: (1)isovolumic contraction, (2) ventricular emptying, (3) isovolumic relaxation and (4) ventricular filling. The area enclosed by the PV loop provides a measure of stroke work and when multiplied by heart rate provides an assessment of cardiac work. This initial examination of PV loops from a single-ventricle decapod crustacean demonstrates the utility of this technique to further elucidate the cardiac mechanics and energetics of this system, and in particular during times of physiological stress.
A male sex pheromone in a parasitic wasp and control of the behavioral response by the female's mating status
Authors: Ruther Joachim , Stahl Lina M. , Steiner Sven , Garbe Leif A. , Tolasch Till
Published: June 2007

Male insects may increase their chance of successful reproduction by releasing pheromones that attract females or elicit sexual acceptance. In parasitic wasps, male pheromones have been suggested for a few species but no chemicals have been identified so far. Here we report the first identification of a male sex pheromone in parasitic Hymenoptera. In abdomens of male jewel wasps, Nasonia vitripennis Walker, we found a mixture of(4R,5R)- and(4R,5S)-5-hydroxy-4-decanolide (HDL), which was released intermittently and attracted virgin females, but no males, in an olfactometer bioassay. However, only a few minutes after copulation mated females avoided the male-derived pheromone. Neither preference nor avoidance was shown by mated females after 24 h and even after they had been allowed to oviposit for 6 days. Nasonia vitripennis females normally mate only once. Thus,their variable response to the sex attractant depending on the mating status makes sense from an evolutionary perspective. Firstly, it increases the chance of virgins to be inseminated. Secondly, by terminating the response or even avoiding the male pheromone, mated females decrease the probability of encountering males and being disturbed by their courtship activities when searching for new oviposition sites.
A comparison of different algorithms for boost pressure control in a heavy-duty turbocharged diesel engine
Authors: Luján J M , Climent H , Guardiola C , García-Ortiz J V
Published: June 2007

Boost pressure control is a critical issue in modern diesel engines. Variable-geometry turbines are widely used and are commonly controlled by the electronic control unit. Basic controllers are based on the proportional-integral-derivative (PID) algorithm. On the other hand, many researchers have developed alternative control algorithms, which improve system performance but usually need a higher parameterization cost. However, the penetration of these new algorithms into the automotive industry has not been important to date. In the present paper, a comparison of different control algorithms applied to the boost pressure control in a heavy-duty diesel engine is presented. The main objective of the paper is quantifying the benefit of implementing advanced control techniques, such as model predictive control.
Detection of plugged injectors in a gasoline engine system using a neural fuzzy scheme
Authors: Chen Pei-Chung
Published: June 2007

An incorrect fuel mixture or the use of inappropriate fuel additives may cause the injectors of a gasoline engine to become restricted, or the needles of the injectors to become stuck. In such an event, the injectors fail to spray normally or may even fail to function at all. Accordingly, this study develops a plugged-injector fault diagnosis system based upon a neural fuzzy scheme. Based upon knowledge of the engine speed, throttle position, injection duration, and vibration frequency, the fuzzy scheme is capable of diagnosing three distinct plugged-injector fault scenarios, namely one permanently plugged injector, two permanently plugged injectors, and one or two temporarily plugged injectors respectively. In addition, a group-injection fault diagnosis system is also developed with the ability to classify further two-plugged-injector fault scenarios as either group-injection faults or ungroup-injection faults. The experimental results confirm the ability of the two systems to diagnose correctly one- and two-plugged-injector faults. Furthermore, it is shown that the neural fuzzy plugged-injector diagnosis scheme provides a more accurate and reliable diagnosis than a polynomial-based approach for the two-plugged-injector fault scenario. Overall, the neural fuzzy schemes proposed in this study provide an efficient and practical means of diagnosing injector faults in gasoline engine systems.
Research on the information fusion method of the Global Positioning System-dead reckoning vehicle integrated navigation system
Authors: Yang Yi , Gu Zhengqi , Hu Lin
Published: June 2007

To overcome the disadvantages of the conventional federated Kalman filter, a fuzzy Kalman filter based on a genetic algorithm (GA) is presented in this paper and applied in the information fusion of the Global Positioning System—dead reckoning vehicle integrated navigation system. The noise covariance and information distribution coefficient of the local filtering are modified online by the fuzzy logic adaptive controller in order to make the Kalman filtering optimal and to improve the positioning accuracy of the integrated navigation system. The acquisition of the membership function of a fuzzy controller usually relies to a great extent on empirical and heuristic knowledge. In this paper, the GA is used to optimize the fuzzy membership function and obtain the optimal or suboptimal control effect. The results of simulations demonstrate the feasibility and effectiveness of the method.
Multiobjective analysis for the design and control of an electromagnetic valve actuator
Authors: Stewart P , Gladwin D , Fleming P J
Published: June 2007

The electromagnetic valve actuator can deliver much improved fuel efficiency and reduced emissions in spark ignition (SI) engines owing to the potential for variable valve timing when compared with cam-operated, or conventional, variable valve strategies. The possibility exists to reduce pumping losses by throttle-free operation, along with closed-valve engine braking. However, further development is required to make the technology suitable for acceptance into the mass production market. This paper investigates the application of multiobjective optimization techniques to the conflicting objective functions inherent in the operation of such a device. The techniques are utilized to derive the optimal force-displacement characteristic for the solenoid actuator, along with its controllability and dynamic/steady state performance.
Multidisciplinary design optimization of a zero-emission vehicle chassis considering crashworthiness and hydroformability
Authors: Cristello Nick , Kim Il Yong
Published: June 2007

This research used multidisciplinary design optimization to optimize the ladder frame chassis of a zero-emission vehicle by simultaneously considering three objective functions: (a) chassis mass, (b) deceleration during collision, and (c) manufacturability of a part in hydroforming. Additionally, design constraints were placed on torsional and bending stiffness, maximum von-Mises stress, and the natural frequency in torsion and bending. Optimization was completed in a three-phase approach: phase one used a simplified chassis model to conduct topology optimization with genetic algorithms; phase two was conducted to determine an optimum cross-sectional type and shape; and phase three incorporated results from phases one and two, into a high-fidelity, three-dimensional chassis model, for gradient-based optimization. Results from all phases of the design optimization indicated that improvements could be made over the baseline configuration. Through examination of Pareto frontiers in phase three, distinct trade-offs were identified between all objective functions: a 5 per cent reduction in chassis mass was required to maximize hydroformability; to minimize mass required a 90 per cent increase in deceleration; and minimization of deceleration required an 18 per cent decrease in hydroformability. Tri-objective optimization was used to generate a three-dimensional Pareto frontier ‘surface’ to show the impact of one objective function on all others simultaneously.
A multi-body head-and-neck model for simulation of rear impact in cars
Authors: Himmetoglu S , Acar M , Taylor A J , Bouazza-Marouf K
Published: June 2007

This paper presents the development and validation of a 50th percentile male multi-body head-and-neck model, aimed primarily at analysing rear impact and the resulting whiplash injury effects. The objective is to design a computationally efficient model behaving like a human head and neck in the case of a rear impact. The volunteer sled tests performed by the Japanese Automobile Research Institute (JARI) have been used for the validation of the head-neck model for low-speed rear-impact analysis. The presented approach for the multi-body head-and-neck model is simple, effective, and capable of producing biofidelic responses. The results show that the model can represent with a high degree of accuracy the rear-impact response of a human.
Optimization of control strategy for a single-shaft parallel hybrid electric vehicle
Authors: Oh Kyoungcheol , Min Junhong , Choi Donghoon , Kim Hyunsoo
Published: June 2007

An optimal control strategy is obtained for a parallel hybrid electric vehicle (HEV). Scale factors in weighting the motor usage are selected as the control variables on how to distribute the demanded vehicle power into the electric motor and the internal combustion engine. Dynamic models of the HEV powertrain are represented by state space equations. In order to find the optimal control strategy, an optimization problem is defined, which finds the optimal control variables to minimize the fuel consumption while satisfying the constraint equations. The optimization problem is solved using the HEV performance simulator developed in MATLAB Simulink and the mathematical optimization sequential quadratic programming algorithm which is based on FORTRAN for multi-variables design optimization. It is expected that the optimization method proposed in this study provides the control strategy of the HEV systematically, which minimizes the fuel consumption.
Evaluation of mass flowrate through an axial gas turbine stage using different computational methods
Authors: Najjar Y. S. H. , Akeel S. A. M. S.
Published: June 2007

Mass flowrate is very important, as it determines the frontal area, volume, size, and weight of the engine, and consequently, the momentum drag at certain flight conditions, specific fuel consumption, and the aircraft total loading. The mass flowrate is also needed to determine the shaft power and the thrust power developed by the engine when the specific work output is obtained.

Different computational methods have been used in this research to find out their relative accuracy in determining the mass flow passing through an already designed, but not built, stage. The methods employed are free vortex variation of density using approximate scheme including mean radius, arithmetic average density, and numerical integration using the trapezoidal and Simpson's rule. Moreover, closed-form integration (theoretical) with free vortex, linear variation, and parabolic variation of density along the height of the blade was considered.

The arithmetic average method was found to give the highest accuracy. The mean-radius method is the least accurate but the simplest. Hence, it is advised to be used especially in quick estimates. The difference in accuracy is not so great to justify using tedious and time-consuming methods.
Material strain hardening in pressure vessel design by analysis
Authors: Camilleri D , Mackenzie D , Hamilton R
Published: June 2007

The effect of including material strain hardening on the gross plastic deformation (GPD) load of four sample problems from the EPERC Design by Analysis manual is investigated. The models considered are two axisymmetric vessels with flat heads under pressure, a nozzle/knuckle intersection under pressure, and a cylinder-cylinder intersection under combined pressure and moment loading. The results of limit analysis, large deformation elastic-perfectly plastic analysis, and small and large deformation bilinear hardening analysis are presented. Plastic loads are calculated using the ASME twice elastic slope (TES) criterion and the plastic work curvature (PWC) criterion. It is found that the plastic pressures given by the ASME TES criterion are inconsistent with respect to the limit load. The PWC criterion is found to represent strain hardening more consistently and lead to enhanced plastic loads. Von Mises equivalent plastic strain plots show that the form and extent of plastic deformation at the limit load in a perfectly plastic analysis and at the plastic load in a strain hardening analysis are similar, indicating a common definition of GPD.
An experimental investigation into the pressure drop for turbulent flow in 90° elbow bends
Authors: Crawford N. M. , Cunningham G , Spence S. W. T.
Published: June 2007

The prediction of the pressure drop for turbulent single-phase fluid flow around sharp 90° bends is difficult owing to the complexity of the flow arising from frictional and separation effects. Several empirical equations exist, which accurately predict the pressure loss due to frictional effects. More recently, Crawford et al. [1] proposed an equation for the prediction of pressure loss due to separation of the flow. This work proposes a new composite equation for the prediction of pressure drop due to separation of the flow, which incorporates bends with ratio R/r < 2. A new composite equation is proposed to predict pressure losses over the Reynolds number range 4 × 103-3 × 105. The predictions from the new equation are within a range of −4 to +6 per cent of existing experimental data.
Evaluation of the critical stroke of an earthworm-like robot for capsule endoscopes
Authors: Kwon Jiwoon , Park Sukho , Park Jongoh , Kim Byungkyu
Published: June 2007

Recently, the capsule endoscope has been highlighted for the patient's convenience and the possibility of application in the small intestine. However, the capsule endoscope has some limitations in obtaining an image of the digestive organ because its movement depends only on the peristaltic motion. In order to solve these problems, it is necessary to determine the locomotive mechanism of the capsule endoscope. Therefore, the present authors have already proposed an earthworm-like robot, which has a locomotive mechanism. However, this mechanism should be designed so that the earthworm-like robot has a larger stroke than the critical stroke required to perform motion inside the small intestine. In this study, therefore, not only is the modelling of the locomotive process based on a biomechanical study presented but also the movement of the earthworm-like robot in the small intestine is simulated. Through the simulation process, the variation in the critical stroke with regard to the elastic modulus of the mesentery is investigated. Finally, from an in vitro test of the proposed robot, it is found that the experimental result is very similar to that of the simulation. Consequently, the present work will provide guidelines for designing an earthworm-like robot for diagnosis of the small intestine.
The development of a model for in vitro testing of femoral stems in impaction bone grafting
Authors: Heal J S , Gozzard C , Gheduzzi S , Grimm B , Learmonth I D , Miles A W
Published: June 2007

Comprehension of the biomechanical behaviour of orthopaedic implants is essential. This paper describes the development of an in vitro model to investigate the behaviour of femoral implants in the revision setting.

The development of a femoral model and a bone graft substitute is described. The properties of human, bovine, ovine morselized bone graft, and a graft substitute were compared. On measuring hoop strain after impaction bone grafting there was no significant difference between the ovine bone graft and graft substitute with the size 1 Exeter stem. The results suggest that this bone graft substitute is a viable alternative for in vitro testing. The authors recommend the use of the graft substitute and the femoral model to predict femoral stem biomechanics.
X-ray-based machine vision system for distal locking of intramedullary nails
Authors: Junejo F , Bouazza-Marouf K , Kerr D , Taylor A J , Taylor G J S
Published: June 2007

In surgical procedures for femoral shaft fracture treatment, current techniques for locking the distal end of intramedullary nails, using two screws, rely heavily on the use of two-dimensional X-ray images to guide three-dimensional bone drilling processes. Therefore, a large number of X-ray images are required, as the surgeon uses his/her skills and experience to locate the distal hole axes on the intramedullary nail. The long-term effects of X-ray radiation and their relation to different types of cancer still remain uncertain. Therefore, there is a need to develop a surgical technique that can limit the use of X-rays during the distal locking procedure. A robotic-assisted orthopaedic surgery system has been developed at Loughborough University to assist orthopaedic surgeons by reducing the irradiation involved in such operations. The system simplifies the current approach as it uses only two near-orthogonal X-ray images to determine the drilling trajectory of the distal locking holes, thereby considerably reducing irradiation to both the surgeon and patient. Furthermore, the system uses robust machine vision features to reduce the surgeon's interaction with the system, thus reducing the overall operating time. Laboratory test results have shown that the proposed system is very robust in the presence of variable noise and contrast in the X-ray images.
Variations in the corneal surface temperature with contact lens wear
Authors: Ooi E H , Ng E Y K , Purslow C , Acharya R
Published: June 2007

This paper presents the two-dimensional simulation of heat propagation in the human eye model during contact lens wear with finite element analysis. Three types of contact lens are studied: Lotrafilcon A, Balafilcon A, and Etafilcon A. The models are solved for both steady and transient solutions. The corneal surface temperature during contact lens wear is found to decrease (average, 0.52 ± 0.05°C compared with a bare cornea for all lens types). A contact lens with a higher water content has a lower steady state temperature than a contact lens with a lower water content does. Various initial temperatures for the contact lens are found to affect the first 400 s of the temperature variation. When the initial temperature is lower than the corneal temperature, a reduction in temperature is observed during contact lens insertion while the opposite is observed when the initial temperature is higher than the corneal temperature. The increase in evaporation rate when a contact lens is worn increases the cooling effect on the ocular surface. This is suggested to be the cause of lower corneal surface temperature when wearing a contact lens.
Experimental investigation into the impact of slipstream wash of a podded propulsor on the marine environment
Authors: Atlar M , Wang D , Glover E J
Published: June 2007

The paper presents the results of an experimental investigation into the velocity field of a podded propulsor carried out by laser Doppler anemometry and the use of this information for assessing the potential impact of a podded propulsor slipstream, in terms of wash velocity, on the marine environment. The investigation was carried out in the Emerson cavitation tunnel of Newcastle University with the roll-on roll-off passenger ship or ferry (ROPAX) hull model as part of the project entitled ‘optimal design and implementation of azimuthing pods for the safe and efficient propulsion of ships’ sponsored by the EU Fifth Framework Programme initiative. Comprehensive velocity field measurements were made in open water, behind the simulated wake of the ROPAX hull and in the bollard pull condition. The mean velocity distributions in the axial and radial directions were calculated from the measured velocity fields to evaluate the potential impact of the slipstream wash of a podded propulsor on the environment. For comparison purposes, some results from similar measurements made with a conventional shafted propeller are also included. The experimental results have revealed that the most significant impact of the propeller slipstream wash on the environment could occur when a ship departs from a port.
Identification of Vertebral Fracture and Non-Osteoporotic Short Vertebral Height in Men: The MrOS Study
Authors: Ferrar Lynne , Jiang Guirong , Cawthon Peggy M , San Valentin Ria , Fullman Robin , Lambert Lori , Cummings Steven R , Black Dennis M , Orwoll Eric , Barrett-Connor Elizabeth , Ensrud Kris , Fink Howard A , Eastell Richard
Published: June 2007

Non-osteoporotic SVH may mimic VF but is excluded in ABQ. In men, this led to discordance between ABQ and other methods, but SVH was not linked to low bone density. Exclusion of SVH could reduce false positives.

Introduction: Non-osteoporotic short vertebral height (SVH) may mimic vertebral fracture (VF). The aims were to (1) compare the prevalence of VF in elderly men using the algorithm-based qualitative (ABQ), semiquantitative (SQ), and triage-quantitative morphometric (triage-QM) methods; (2) identify reasons for discordance between methods; and (3) determine whether SVH identified by ABQ is linked to low BMD.

Materials and Methods: We studied a subset of 732 men ages ≥65 yr participating in the Osteoporotic Fractures in Men (MrOS) Study. Criteria for VF were (1) ABQ: endplate depression; (2) SQ: estimated vertebral height reduction ≥20%; (3) triage-QM: vertebral height ratio >3 SD below the reference mean, on radiographs showing evidence of VF. Criteria for SVH (ABQ) were apparent “reduction” in vertebral height ≥ ∼15%, without evidence of endplate depression.

Results: The prevalence of at least one VF was 10% (ABQ); 13% (SQ) and 11% (QM-triage) and of at least one SVH (ABQ) was >50%. Agreement between methods was moderate (κ = 0.42–0.62). Discordance between methods related mainly to classification of mild thoracic wedging or possible traumatic VF by ABQ. Mean BMD was lower in men with VF (any diagnostic method) than in those without (two-sample t-test, p < 0.05). For ABQ, BMD was similar in men with SVH (no VF) and men with normal vertebrae (ANOVA, p > 0.05). Mean BMD was significantly lower than expected in 40 men with VF identified by all three methods and average or more than average in those identified by a single method.

Conclusions: Among elderly men (1) the prevalence of VF ranges from 10% to 13%: (2) agreement between diagnostic methods is moderate: discordance relates mainly to differential classification of mild thoracic deformities or ABQ definition of VF as traumatic; and (3) SVH identified by ABQ is common and not linked to low BMD.
Microcrack Frequency and Bone Remodeling in Postmenopausal Osteoporotic Women on Long-Term Bisphosphonates: A Bone Biopsy Study
Authors: Chapurlat Roland D , Arlot Monique , Burt-Pichat Brigitte , Chavassieux Pascale , Roux Jean Paul , Portero-Muzy Nathalie , Delmas Pierre D
Published: June 2007

We sought whether microdamage could rise in postmenopausal osteoporotic women on long-term bisphosphonates, as suggested by recent animal studies. We found few microcracks in iliac bone biopsies, despite a marked reduction in bone turnover.

Introduction: Animal studies suggest that bisphosphonates (BPs) could increase microdamage frequency in a dose-dependent manner, caused by excessively suppressed bone turnover. However, there is limited data in humans receiving BP therapeutic doses for >3 yr.

Materials and Methods: We measured microcrack frequency and histomorphometry parameters on transiliac bone biopsies in 50 postmenopausal osteoporotic women (mean age = 68 yr) who had received BP therapy (3 on intravenous pamidronate, 37 on oral alendronate, and 10 on oral risedronate) for at least 3 yr (mean treatment duration = 6.5 yr). We compared these results with transiliac bone biopsies obtained from 12 cadavers. We used bulk staining with green calcein as a fluorochrome. The microcracks were quantified in three 100-μm-thick sections using optic microscopy and were confirmed by laser confocal microscopy. Microcrack frequency (number of microcracks/mm2 of bone tissue) was compared between treated women and controls using nonparametric tests. We also explored predictors of microcrack frequency, including age, duration of BP therapy, and activation frequency.

Results: Among treated women, cancellous bone microcrack frequency was low (mean, 0.13 microcracks/mm2) and did not differ significantly from that observed in controls (0.05 microcracks/mm2; p = 0.59). Of note, 54% of the treated women and 58% of the controls had no observable microcracks. There was no association between microcrack frequency and the duration of BP therapy (for microcracks/mm2 and duration, Spearman r = 0.04, p = 0.80) and between patients' ages and the number of microcracks (Spearman r = −0.09, p = 0.61). Although bone remodeling parameters were suppressed in treated women, we found no relationship between microcrack density and activation frequency (Spearman r = −0.003, p = 0.99). Also, microcrack frequency was not increased in women with prevalent vertebral fracture compared with those without fractures.

Conclusions: Among postmenopausal osteoporotic women on long-term BPs, microcrack frequency in the iliac bone is low, despite a marked reduction of bone turnover.
Patterns of Men’s Use of Sexual and Reproductive Health Services
Authors: Kalmuss Debra , Tatum Carrie
Published: June 2007

CONTEXT:  Men have been neglected as a target population for sexual and reproductive health services. As a result, little is known about the rates and antecedents of men’s service utilization.

METHODS:  Data from the 2002 National Survey of Family Growth were used to examine utilization of sexual and reproductive health services among 3,611 men aged 20–44 who had ever had sex with a woman. Associations between demographic and behavioral variables and measures of service utilization were assessed in univariate and logistic regression analyses.

RESULTS:  Only 48% of men reported receiving sexual and reproductive health services in the past year. The testicular exam was the most commonly received service (35%), but half of men who had had a testicular exam had received no other sexual and reproductive health services. Levels of unmet need for services among men engaging in sexual risk behaviors were substantial (32–63%). The odds of having received nontesticular services were elevated among men who were nonwhite and older, engaged in sexual risk behaviors, had had a physical exam and had public health insurance. The odds of having received only a testicular exam were elevated among men who were white, had lower levels of sexual risk, had had a physical exam and had private or no insurance.

CONCLUSIONS:  Men who have sex with women are not receiving adequate levels of sexual and reproductive health care, and the care they receive is neither comprehensive nor integrated. Standards of clinical care need to be defined and communicated to men and providers.
I Wanna Hold Your Hand: The Progression of Social, Romantic and Sexual Events in Adolescent Relationships
Authors: O’Sullivan Lucia F. , Cheng Mariah Mantsun , Harris Kathleen Mullan , Brooks‐Gunn Jeanne
Published: June 2007

CONTEXT:  Despite the vast amount of existing research on adolescent sexual behavior, little is known about the trajectory of social, romantic and sexual events within an adolescent’s relationship.

METHODS:  A subsample of participants in Wave 2 of the National Longitudinal Study of Adolescent Health (8,438 respondents aged 12–21) provided data on the sequence of 15 social, romantic and sexual events that occurred in a recent romantic relationship. Proportions reporting each event and average relative rankings were assessed for all respondents, for different racial and ethnic groups, and for respondents who belonged to the same racial or ethnic group as their partner. Logistic regression was used to compare proportions; ordinary least square regression was used to analyze the mean sequential ranking of each event.

RESULTS:  Social and romantic events, such as spending time with one’s partner in a group and holding hands, were far more common than sexual events, such as touching one’s partner without clothing, and typically preceded sexual events in the trajectory of relationship events. Romantic events were the most common across three of the four major U.S. racial and ethnic groups. Asian and Hispanic respondents tended to have low proportions reporting sexual events compared with white respondents. Black adolescents were the only group for whom talking about prevention of pregnancy and STDs preceded sexual events. Reports from male and female adolescents were similar.

CONCLUSION:  Recognition of the diversity of relationship experiences may prompt the development of more effective interventions for adolescents who engage in risky sexual behavior.
Proximate Composition and Collagen Concentration of Processing Residue of Channel Catfish
Authors: Li Menghe H , Robinson Edwin H , Oberle Daniel F , Bosworth Brian G
Published: June 2007

Residues—including heads, skin, viscera, frames, and trimmings—from the channel catfish Ictalurus punctatus processing industry have generally been made into catfish meal and catfish oil that are used in animal feeds. There may be more efficient uses for these materials, such as producing collagen and other products. A study was conducted to determine the percentages of each component of the processing residue relative to whole fish weight and their crude protein, crude fat, moisture, ash, and collagen concentrations. Of a market-size channel catfish, the head accounted for 24% of the whole weight, the frame 13.6%, the viscera 10.8%, the skin 4.7%, and the trimmings 3.7%. These processing residues represent a total of 56.8% of the total fish weight. The highest crude protein and collagen concentrations were found in the skin (protein, 19.9% of wet tissue and 82.1% of dry matter; collagen, 14.2% of wet tissue and 58.7% of dry matter). The viscera had the highest fat level (32.7% of wet tissue and 69.6% of dry matter). The head remnants had the highest ash concentration (6.9% of wet tissue and 19.9% of dry matter). The skin had a high collagen concentration and is therefore a good candidate for collagen production.
Preliminary Investigations of Hydrogen Peroxide Treatment of Selected Ornamental Fishes and Efficacy against External Bacteria and Parasites in Green Swordtails
Authors: Russo Riccardo , Curtis Eric W. , Yanong Roy P. E.
Published: June 2007

The objectives of these preliminary studies were to evaluate the use of hydrogen peroxide (H2O2) for the treatment of selected species of ornamental fishes and its efficacy in treating external bacteria and parasites. In the first part of the study, fish of five species (serpae tetra Hyphessobrycon eques (also known as Serpa tetra H. serpae), tiger barb Puntius tetrazona, blue gourami Trichogaster trichopterus, suckermouth catfish Hypostomus plecostomus, and green swordtail Xiphophorus hellerii) were exposed to H2O2 for 1 h at concentrations between 6 and 34 mg/L or for 24 h at concentrations between 1 and 6 mg/L. The results were species specific: green swordtails tolerated all of the treatments, serpae tetras and tiger barbs were sensitive only to the highest concentration, and mortalities of suckermouth catfish and blue gourami were recorded in every treatment. In the second part of the study, clinically healthy green swordtails and fish infested with external motile rod-shaped bacteria (i.e., Ichthyobodo spp., Trichodina spp., and Gyrodactylus spp.) were treated with several concentrations of H2O2. A single H2O2 treatment of 3.1 mg/L or more for 1 h effectively eliminated external bacteria, concentrations of 6.5 mg/L or more appeared to effectively kill Ichthyobodo spp., and none of the treatments tested was effective against Trichodina spp. or Gyrodactylus spp. These preliminary findings suggest that H2O2 is effective for treating certain external bacterial infections and flagellate infestations in some species of ornamental fish at the dosages tested. Other treatment regimens may need to be tested for effectiveness against Trichodina spp. and Dactylogyrus spp.