bluuebunny/crossref_metadata_2025 huggingface dataset:
Ventilation Tube Treatment
Authors: Hellström Sten , Groth Anita , Jörgensen Finn , Pettersson Agneta , Ryding Marie , Uhlén Inger , Boström Kristina Bengtsson
Published: June 2011

Objective

The aim of this review was to study the effectiveness of ventilation tube (VT) treatment in children with secretory otitis media (SOM), assessed by improved hearing, normalized language and quality of life (QoL), and recurrent acute otitis media (rAOM), assessed by number of episodes of AOM and QoL.

Data Sources

Cochrane Library, PubMed, and Embase databases were searched for randomized and nonrandomized controlled trials and cohort studies in English, Scandinavian, German, and French languages between 1966 and April 2007. Additional literature was retrieved from reference lists in the articles.

Review Methods

A total of 493 abstracts were evaluated independently by 2 members of the project group, 247 full‐text versions were assessed for inclusion criteria and quality using structured evaluation forms, and 63 articles were included in the review.

Results and Conclusions

This review shows that there is strong scientific evidence (grade 1) that VT treatment of SOM improves hearing for at least 9 months and that QoL is improved for up to 9 months (grade 2 scientific evidence). There was insufficient evidence to support an effect of VT treatment for rAOM. There was also insufficient evidence to determine whether the design or material of the VT or the procedure used for insertion had any influence on the effect; however, there was some evidence (grade 3) that aspiration of secretion at insertion does not prolong VT treatment. Further research is needed to address these issues.
Diagnostic Value of Bent‐Lever Planes in Detecting Abnormality of the Malleus‐Incus Complex
Authors: Quan Yong , Wu Lebin , Li Jianfeng , Xu Zushan , Gong Ruozhen
Published: June 2011

Objective

To retrospectively investigate the diagnostic value of the bent‐lever planes in detecting abnormality of the malleus‐incus complex.

Study Design

Diagnostic test assessment.

Setting

The study was conducted at the Shandong Medical Imaging Research Institute, Shandong University, Jinan, People’s Republic of China.

Subjects

Eighty‐five ears in 74 patients with surgically proved abnormality of the malleus‐incus complex.

Materials and Methods

The bent‐lever planes and direct axial images were reviewed by 2 radiologists. The radiologists assigned a value of abnormality or continuity to different parts of the malleus‐incus complex. Differences in categorical data were evaluated with the McNemar test. The sensitivity, specificity, Youden index, and interobserver agreement were calculated.

Results

There was no significant difference between bent‐lever planes and direct axial images in identifying abnormality of the malleus‐incus complex. The sensitivity ranged from 71.4% to 97.1%, and specificity ranged from 89.5% to 100.0%. The Youden index ranged from 0.609 to 0.971. The radiologists had almost perfect or substantial agreement in identifying the abnormality of different parts of the malleus‐incus complex.

Conclusion

The bent‐lever planes do not add additional diagnostic value for experienced observers.
Treatment of Velopharyngeal Insufficiency by Pharyngeal and Velar Fat Injections
Authors: Cantarella Giovanna , Mazzola Riccardo F. , Mantovani Mario , Baracca Giovanna , Pignataro Lorenzo
Published: June 2011

The aim of this prospective study was to evaluate the effectiveness of fat injections in the treatment of velopharyngeal insufficiency (VPI). The study involved 10 patients (6 adults aged 19‐48 years and 4 children aged 5‐13 years) with mild/moderate VPI who were injected with 3.5 to 8 mL of fat in the posterior, lateral pharyngeal walls and soft palate under general anaesthesia. A second fat‐grafting procedure was performed in 2 patients to achieve further improvement. Nasoendoscopy revealed a reduction in the closure gap in all patients, and the perceptual evaluation demonstrated improved speech intelligibility and resonance and reduced nasal air leakage in all cases (P <. 005). The aerodynamic assessment showed a significant reduction in nasal airflow during phonation (P <. 05). Follow‐up was 6 to 23 months. In conclusion, fat injections improved voice resonance and reduced nasal air escape in all treated cases and can be a promising alternative to major procedures, such as velopharyngoplasties, for the treatment of mild/moderate VPI.
Simulation of Quality-Adjusted Survival in Chronic Diseases
Authors: Hayes Alison J. , Clarke Philip M. , Voysey Merryn , Keech Anthony
Published: June 2011

Background. Recent studies have demonstrated that measures of health-related quality of life can predict complications and mortality in patients with diabetes, even after adjustment for clinical risk factors. Methods. The authors developed a simulation model of disease progression in type 2 diabetes to investigate the impact of patient quality of life on lifetime outcomes and its potential response to therapy. Changes in health utility over time are captured as a result of complications and aging. All risk equations, model parameter estimates, and input data were derived from patient-level data from the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) trial. Results. Healthier patients with type 2 diabetes enjoy more life years, quality-adjusted life years (QALYs), and more life years free of complications. A 65-year-old patient at full health (utility = 1) can expect to live approximately 2 years longer and achieve 6 more QALYs than a patient at average health (utility = 0.8), given similar clinical risk factors. For patients with higher EQ-5D utility, the additional years lived without complications contribute more to longer life expectancy than years lived with complications. Conclusions. The authors have developed a model for progression of disease in diabetes that has a number of novel features; it captures the observed relationships between measures of quality of life and future outcomes, the number of states have been minimized, and it can be parameterized with just 4 risk equations. Underlying the simple model structure is important patient-level heterogeneity in health and outcomes. The simulations suggest that differences in patients’ EQ-5D utility can account for large differences in QALYs, which could be relevant in cost-utility analyses.
What Is the Impact of Online Resource Materials on Student Self-Learning Strategies?
Authors: Dowell David John , Small Felicity A.
Published: June 2011

The purpose of this article is to examine how students are incorporating online resources into their self-regulated learning strategies. The process of developing these learning strategies and the importance of these strategies has been widely researched, but there has been little empirical research into how the students are affected by online environments. This preliminary study focused on the relationship between the use of online resources and the students’ overall outcome in the subject. The data were collected from first year on-campus ( n = 105) and distance education ( n = 258) students after completing their introductory marketing subject. The data were analyzed using correlations, simple regression, and Tobit regression to assess online activity and student outcomes. The results indicate that the use of these online resources has a significant and positive effect on the students’ grade. This finding suggests students are incorporating online environments into their learning strategies, which results in higher grades. Moreover, in practical terms, the results imply that teachers can help facilitate student self-learning strategies by creating encouraging and resource-rich online environments.
Is Twitter for the Birds?
Authors: Lowe Ben , Laffey Des
Published: June 2011

Recent years have seen unprecedented possibilities for the use of different technologies to enhance learning in marketing courses. Given the rapid and widespread diffusion of these technologies, particularly within the demographic of the student population, it is pertinent to explore and examine how such technologies can benefit student learning. This article discusses and empirically evaluates students’ experiences of using Twitter as a tool to facilitate learning in marketing courses. Although Twitter’s unique characteristics were used to enhance and facilitate the learning of marketing concepts, the use of Twitter also helped illustrate marketers’ use of innovative technologies and, therefore, added valuable contemporary curriculum content. Using in-depth interviews, and a questionnaire to evaluate learning outcomes, this research concludes that students’ perceptions of using Twitter were largely positive, though some anticipated and unanticipated barriers emerged to incorporating Twitter into marketing courses. Recommendations for adopting Twitter into the marketing curriculum are made, and future areas for research are identified.
Accurate displacement field measurement with scanning electron microscopy imaging
Authors: Arikawa T , Murasawa G , Yoneyama S
Published: June 2011

This study was undertaken to measure the displacement field accurately by application of digital image correlation (DIC) to scanning electron microscopy (SEM) images. First, a method of removing the noise and drift that arise in SEM images is proposed. Second, a compact slide machine is fabricated. Third, a translation test is performed under optical microscopy and SEM using the slide machine. Then a displacement field calculation is performed using the proposed image analysis method. The results show that the proposed method is adequate for the application of DIC to SEM images.
Microdeformation measurement via single-element extended digital image correlation
Authors: Chen J , Zhang X , Wang R
Published: June 2011

The microdeformation measurement of biomaterials is a crucial issue in the field of experimental mechanics. The single-element extended digital image correlation (single-element X-DIC) method was developed in this paper. If the actual deformation of the specimen is in accordance with the displacement hypothesis, single-element X-DIC possesses a higher measurement accuracy and a higher computational efficiency. With the assistance of a novel discretization method, single-element X-DIC could be used to measure the complex deformation. All results of the verification experiment show that single-element X-DIC is suitable for the measurement of various deformations. Furthermore, combined with optical microscopy, single-element X-DIC was applied to measure the microdeformation of bovine bone, which demonstrates that single-element X-DIC has wide application prospects in the microdeformation measurement of biomaterials.
Integrated headache care
Authors: Diener H-C , Gaul C , Jensen R , Göbel H , Heinze A , Silberstein SD
Published: June 2011

Patients with chronic or difficult to treat headaches are generally under the care of general practictioners or neurologists in private practice. Some are referred to a headache specialist for evaluation and advice. Treatment is often provided by the referring physician. An alternative is a multidisciplinary headache centre, where care is provided by different disciplines (neurology, behavioural psychology, psychiatry, psychosomatic medicine, physical therapy, sport therapy) across sectors of the healthcare system involving out- and inpatient care and treatment. This is called integrated headache care. This review summarizes experiences in integrated headache care settings in Europe and the USA, describes these settings, and reports outcome data.
A Dual Process Motivational Model of Ambivalent Sexism and Gender Differences in Romantic Partner Preferences
Authors: Sibley Chris G. , Overall Nickola C.
Published: June 2011

We tested a dual process motivational model of ambivalent sexism and gender differences in intimate partner preferences. Meta-analysis of 32 samples (16 with men, 16 with women; N = 5,459) indicated that Benevolent Sexism (BS) in women was associated with greater preferences for high-resource partners ( r = 0.24), whereas Hostile Sexism (HS) in men was associated with stronger preferences for physically attractive partners ( r = 0.20). Study 2 examined the ideological correlates of this gender difference ( N = 249 men, 243 women). For women, Right-Wing Authoritarianism (RWA) was associated with greater preferences for high-resource partners, mediated by BS. For men, Social Dominance Orientation (SDO) was associated with greater preferences for attractive partners, mediated by HS. These findings indicate that women’s desire for high-resource partners is related to a protection and security-provision motive, whereas men’s desire for attractive partners is related to a dominance-based status-marker motive. Gender differences in these dual motives have implications for understanding the reciprocal reinforcement of gender inequality. We argue that they exacerbate gender inequality by decreasing women’s immediate motivation for direct access to resources (because they may be provided for by men) and promoting instead goals in women relating to the maintenance of an attractive appearance valued by men.
Platelet-Rich Plasma Protects Tenocytes From Adverse Side Effects of Dexamethasone and Ciprofloxacin
Authors: Zargar Baboldashti Nasim , Poulsen Raewyn C. , Franklin Sarah L. , Thompson Mark S. , Hulley Philippa A.
Published: June 2011

Background: Ruptured tendons heal very slowly and complete recovery from injury is uncertain. Platelet-rich plasma (PRP), a rich source of growth factors, is currently being widely tested as a soft tissue healing agent and may accelerate tendon repair. The authors assessed the ability of PRP to prevent in vitro adverse effects of 2 drugs commonly linked to tendon rupture and tendinopathy, glucocorticoids and fluoroquinolone antibiotics.

Hypothesis: The pro-healing response induced by PRP protects human tenocytes against the cytotoxic effects of dexamethasone and ciprofloxacin.

Study Design: Controlled laboratory study.

Methods: Human primary hamstring tenocytes were exposed to different doses of ciprofloxacin and dexamethasone with and without PRP. AlamarBlue, β-galactosidase assay, and live/dead stain were used to measure, respectively, viability, senescence, and death in tenocyte culture.

Results: The viability of cells exposed to high doses of ciprofloxacin was significantly decreased compared with controls, with no induced senescence but increased cell death. Dexamethasone reduced viable cell number without inducing overt cell death, but the number of senescent cells increased considerably. After co-treatment with 10% PRP, viable cell number increased significantly in both conditions and the number of dead cells decreased in ciprofloxacin-treated cultures. Moreover, dexamethasone-induced senescence was markedly reduced by co-treatment with 10% PRP.

Conclusion: This study demonstrates that ciprofloxacin and dexamethasone have differing adverse effects on human tenocytes, with ciprofloxacin inducing cell death while dexamethasone primarily induces senescence. The authors showed that PRP can protect cultured human tenocytes against cell death or senescence induced by these drugs.

Clinical Relevance: Both ciprofloxacin and dexamethasone are highly effective in treatment of inflammatory and infectious conditions, therefore new strategies to minimize their adverse effects are of strong interest. These findings suggest the potential for local administration of PRP to enhance tendon healing in patients undergoing glucocorticoid or fluoroquinolone treatment.
Is Hip Muscle Weakness a Predisposing Factor for Patellofemoral Pain in Female Novice Runners? A Prospective Study
Authors: Thijs Youri , Pattyn Els , Van Tiggelen Damien , Rombaut Lies , Witvrouw Erik
Published: June 2011

Background: Hip muscle weakness has been proposed to contribute to patellofemoral malalignment and the development of the patellofemoral dysfunction syndrome (PFDS). However, from the retrospective studies that have addressed this issue, it is still unclear if hip muscle weakness is a cause or a consequence of PFDS.

Purpose: This study was undertaken to investigate if hip muscle weakness is a predisposing factor for the development of PFDS.

Study Design: Cohort study (prognosis); Level of evidence, 2.

Methods: Before the start of a 10-week “start to run” program, the isometric strength of the hip flexor, extensor, abductor, adductor, and external and internal rotator muscles was measured in 77 healthy female novice runners. During the 10-week training period, patellofemoral pain was diagnosed and registered by an orthopaedic surgeon.

Results: Statistical analysis revealed that there was no significant difference in strength of any of the assessed hip muscle groups between the runners who did and did not develop PFDS. Logistic regression analysis did not identify a deviation in strength of any of the assessed hip muscle groups as a risk factor for PFDS.

Conclusion: The findings of this study suggest that isometric hip muscle strength might not be a predisposing factor for the development of PFDS.
Treatment of Jones Fracture Nonunions and Refractures in the Elite Athlete
Authors: Hunt Kenneth J. , Anderson Robert B.
Published: June 2011

Background: Fractures of the proximal fifth metatarsal metaphysis (ie, the Jones fracture) can be problematic in the elite athlete because of a high incidence of nonunion and refracture with nonoperative treatment. Although these fractures are not common, athletes can suffer refracture or nonunion of a Jones fracture despite operative stabilization. This is often attributable to hardware of insufficient strength, aggressive postoperative rehabilitation, or biologic insufficiency at the fracture site.

Purpose: The authors review the results of revision intramedullary screw fixation with cancellous autologous bone grafting or bone-marrow aspirate combined with demineralized bone matrix after refracture or nonunion of Jones fractures in elite athletes.

Study Design: Case series; Level of evidence, 4.

Methods: The authors retrospectively reviewed the clinical and radiographic outcomes and return to sport in 21 elite athletes undergoing treatment of Jones fracture refractures or nonunions. All patients underwent intramedullary screw fixation with autologous bone graft (12 patients), bone-marrow aspirate (BMA) + demineralized bone matrix (DBM) (8 patients), or no bone graft (1 patient).

Results: All athletes were able to return to their previous level of athletic competition at an average of 12.3 weeks. All fractures showed clinical and radiographic evidence of compete cortical healing. Only 1 patient subsequently suffered a refracture.

Conclusion: The authors recommend revision fixation with a large, solid screw (5.5 mm or larger) and autologous bone grafting for symptomatic refractures and nonunions of the proximal fifth metatarsal in elite athletes. Additional investigation is needed to determine whether BMA combined with DBM is an effective substitute for cancellous autograft.
Hypoglycemic effect of basil (Ocimum basilicum) aqueous extract is mediated through inhibition of α-glucosidase and α-amylase activities
Authors: El-Beshbishy HA , Bahashwan SA
Published: June 2011

The present study investigated the in vitro hypoglycemic activity of basil ( Ocimum basilicum) aqueous extract. Preliminary phytochemical screening of the extract revealed the presence of reducing sugars, cardiac glycosides, tannins, saponins, glycosides, flavonoids and steroids. The total polyphenols content (TPC), flavonoids content (FC), percentage diphenylpicrylhydrazyl (DPPH·) radical inhibition and total antioxidant status (TAS) were estimated. The FC was 41 ± 2.2 rutin/g dry extract, the TPC was 146 ± 5.26 mg catechin/g dry extract and the TAS was 5.12 ± 0.7 mmol/L. The %DPPH· free radical inhibition was 60%, 54%, 49% and 43%, respectively, for different extract concentrations; 20, 18.2, 16.3 and 14.5 mg/ml, respectively. The extract elicited significant dose-dependent pattern against rat intestinal sucrase (RIS; IC50 = 36.72 mg/ml), rat intestinal maltase (RIM; IC50 = 21.31 mg/ml) and porcine pancreatic α-amylase (PPA; IC50 = 42.50 mg/ml) inhibitory activities. The inhibition was greater against maltase compared with sucrase. These effects may be attributed to the high TPC and FC levels. The linear regression analysis revealed strong significant positive correlations between %DPPH· radical inhibition and each of %RIS, %RIM and %PPA inhibiting activity. Also, strong significant positive correlations between %RIS and either %RIM or %PPA inhibition activity were observed. We concluded therefore that basil aqueous extract via antioxidant and possibly α-glucosidase and α-amylase inhibiting activities, offered positive benefits to control diabetes.
Electroencephalogram, cognitive state, psychological disorders, clinical symptom, and oxidative stress in horticulture farmers exposed to organophosphate pesticides
Authors: Bayrami Mansour , Hashemi Touraj , Malekirad Ali Akbar , Ashayeri Hassan , Faraji Fardin , Abdollahi Mohammad
Published: June 2011

The aim of this paper was to study the toxicity of organophosphate (OP) pesticides in exposed farmers for electroencephalography, cognitive state, psychological disorders, clinical symptom, oxidative stress, acetylcholinesterase, and DNA damage. A comparative cross-sectional analysis was carried out in 40 horticulture farmers who were exposed to OPs in comparison to a control group containing 40 healthy subjects with the same age and sex and education level. Lipid peroxidation (LPO), superoxide dismutase (SOD), catalase, glutathione peroxidase, DNA damage, total antioxidant capacity (TAC), total thiol molecules, and acetylcholinesterase (AChE) activity were measured in the blood of subjects. Clinical examination and complete blood test were undertaken in order to record any abnormal sign or symptoms. Cognitive function, psychological symptoms, and psychological distress were examined and recorded. Comparing with controls, the farmers showed higher blood levels of SOD and LPO while their TAC decreased. Farmers showed clinical symptoms such as eczema, breathing muscle weakness, nausea, and saliva secretion. Regarding cognitive function, the orientation, registration, attention and calculation, recall, and language were not significantly different in farmers and controls. Among examinations for psychological distress, only labeled somatization was significantly higher in farmers. The present findings indicate that oxidative stress and inhibition of AChE can be seen in chronically OP-exposed people but incidence of neuropsychological disorders seems a complex multivariate phenomenon that might be seen in long-term high-dose exposure situations. Use of supplementary antioxidants would be useful in the treatment of farmers.
Magnetic Resonance Imaging Findings in Reye Syndrome
Authors: Singh Paramdeep , Goraya Jatinder S. , Gupta Kamini , Saggar Kavita , Ahluwalia Archana
Published: June 2011

Magnetic resonance imaging findings in Reye syndrome have been reported only infrequently. A previously well 8-year-old boy presented with repeated episodes of vomiting and abdominal pain followed by altered sensorium and tonic spasms. This occurred 5 days after upper respiratory tract infection. His laboratory data revealed elevated liver enzymes, prolonged prothrombin time, and high blood ammonia levels. Magnetic resonance imaging of the brain done on the day of admission revealed diffuse cerebral edema and signal alterations in brainstem, bilateral thalami, medial temporal lobes, parasagittal cortex, and cerebellar and subcortical white matter. Diffusion restriction was seen in thalami, midbrain, cerebellar white matter, subcortical white matter, and parasaggital cortex in the watershed territory. The patient made a full recovery. Follow-up magnetic resonance imaging after a week revealed complete resolution of all except thalamic lesions. Although diffusion restriction in thalami and midbrain has been reported previously, this is the first report indicating diffusion restriction in subcortical white matter and the parasagittal cortex.
Endovascular Treatment of a Pial Arteriovenous Fistula With Occipital Remodeling Secondary to Giant Torcular Dilation
Authors: Aguilar Marta , González Alejandro , López Antonio , Gutiérrez Isabel , Durand Fernando , Mayol Antonio
Published: June 2011

Intracranial arteriovenous fistulas are vascular malformations in which clinical suspicion and prompt diagnosis, with a subsequent appropriate therapeutic approach, are crucial to avoid the development of irreversible neurological damage or even patient death because these lesions can be associated with heavy bleeding and high mortality rates. The authors present the case of a direct pial arteriovenous fistula in an infant and its unusual presentation as a large occipital protuberance with hard consistency and an audible murmur that produced bone remodeling. The patient was successfully treated by endovascular therapy, with complete regression of the occipital protuberance during follow-up.
Change in Gross Motor Abilities of Girls and Women With Rett Syndrome Over a 3- to 4-Year Period
Authors: Foley Kitty-Rose , Downs Jenny , Bebbington Ami , Jacoby Peter , Girdler Sonya , Kaufmann Walter E. , Leonard Helen
Published: June 2011

Rett syndrome is a rare but severe neurological disorder typically associated with a mutation in the MECP2 gene. We describe change in gross motor function over 3 to 4 years for 70 subjects participating in the Australian Rett Syndrome Database. Linear regression was used to assess relationships with age, genotype, and general and complex gross motor skills scores measured on the Gross Motor Scale for Rett syndrome. Skills were slightly better or maintained in approximately 40% of subjects and slightly decreased in approximately 60%. Teenagers and women who walked in 2004 were less likely to lose complex skills than those younger. Girls with a p.R294X mutation were more likely to lose complex motor skills, otherwise skill changes were spread across the mutation categories. In conclusion, small changes were observed over this period with greater stability of skills in teenagers and women with the ability to walk.
Abnormal Brain Protein Synthesis in Language Areas of Children With Pervasive Developmental Disorder
Authors: Shandal Varun , Sundaram Senthil K. , Chugani Diane C. , Kumar Ajay , Behen Michael E. , Chugani Harry T.
Published: June 2011

This study was performed to evaluate the cerebral protein synthesis rate of language brain regions in children with developmental delay with and without pervasive developmental disorder. The authors performed L-[1-11C]-leucine positron emission tomography (PET) on 8 developmental delay children with pervasive developmental disorder (mean age, 76.25 months) and 8 developmental delay children without pervasive developmental disorder (mean age, 77.63 months). They found a higher protein synthesis rate in developmental delay children with pervasive developmental disorder in the left posterior middle temporal region ( P = .014). There was a significant correlation of the Gilliam Autism Rating Scale autism index score with the protein synthesis rate of the left posterior middle temporal region ( r = .496, P = .05). In addition, significant asymmetric protein synthesis (right > left) was observed in developmental delay children without pervasive developmental disorder in the middle frontal and posterior middle temporal regions ( P = .03 and P = .04, respectively). In conclusion, abnormal language area protein synthesis in developmentally delayed children may be related to pervasive symptoms.
Urban Form Relationships with Youth Physical Activity
Authors: Loon Joshua van , Frank Lawrence
Published: June 2011

This article summarizes and synthesizes empirical research on relationships between youth physical activity and urban form across several disciplines, for a planning audience. It highlights how physical activity is characterized, introduces ecological theories of physical activity behavior, provides a conceptual model of interactions between urban form and other influences on youth physical activity behavior, and discusses implications of new evidence for future research and policy. Further research is needed to address several gaps and inconsistencies across studies and to build on recent methodological developments. Despite the limitations of existing research, it is evident that urban form can either serve to constrain or promote physical activity. Urban form interventions have the potential to result in lasting influences on the behavior of large populations of youth.
Spatial Planning Models of Airport-Driven Urban Development
Authors: Freestone Robert , Baker Douglas
Published: June 2011

Airports have been relatively neglected in scholarly planning literature despite their historic role in shaping metropolitan form. Their transformation into major mixed-use urban nodes anchoring subregional realms of aviation-oriented development has underscored their significance as agents of and products of globalization. Reviewing the trends and planning issues arising, several normative models of airport spaces are identified and discussed in relation to sustainable development objectives. The contestation of airport expansion that has made for epic political battles in diverse settings and its implications for models of airport-led urban development is noted. The review is guided by the notion of the sustainable airport region, which ultimately requires a rapprochement between airport master plans and broader urban planning strategies.
Educational Equity in Spain and Norway: A Comparative Analysis of Two OECD Country Notes
Authors: Ronning Haugen Cecilie
Published: June 2011

This article undertakes a comparative study of the Organization for Economic Co-operation and Development’s (OECD) thematic reviews on “equity in education” for Spain and Norway. The author investigates whether there may be a similar orientation to equity expressed in the two reviews and discusses how social stratification may occur within the recommendations to improve equity. The author claims that special attention should be paid to how “multiculturalism” is combined with “national measurements of key performance indicators” and how the “objective” definition of schools as good or bad through national testing may affect the demography of the schools. Targeting the inequity that may arise through a conservative modernization, the author finds that it is important to employ an expanded concept of “educational policy.”
Volunteer Motivations and Constraints Among College Students
Authors: Gage Richard L. , Thapa Brijesh
Published: June 2011

This research examined motivational factors of college students to volunteer in various capacities using the Volunteer Function Inventory. Volunteering characteristics, scope of volunteerism, volunteer segments, and type of contributions were investigated. In addition, constraints to participation based on the leisure constraint model were explored. Data were collected at a major university in the southeast United States. Results identified that the majority were involved in volunteerism in some capacity. Organizations that focused on human services were the most important type of organizations to volunteers. Families and teachers were responsible for introducing almost the majority to volunteerism. Also, more than half reported time as their most important contribution. The strongest motives were related to the values and understanding dimension which reflected helping others and expanding one’s own perspective on an issue. Structural constraints were most likely to limit volunteerism. Several associations between motivations and constraints were further examined and discussed.
Lethal differences: a short history of the concepts of wealth and poverty in Danish epidemiological writings 1858-1914
Authors: Christensen Ivan Lind
Published: June 2011

Through a study of the history of the concepts of wealth and poverty, this paper investigates the onset of a transition in the conceptual architecture of epidemiological research concerning social differences in mortality rates from 1858 to 1914. It raises the question as to what the concepts of wealth and poverty meant to those who used them and what objects of interventions the conceptual architecture surrounding the concepts enabled the researchers to create. It argues that a transition began in the late 19th century in which an important framework for the understanding of causal relations behind the mortality patterns changed and that this change in turn influenced the scope of what was conceived as relevant objects of intervention.
Ferdinand Tönnies and academic ‘socialism’
Authors: Bond Niall
Published: June 2011

Modern sociology emerged in part out of the milieu of ‘state socialists’ in imperial Germany. An exploration of the milieu and its discourses provides insights as to the sense of the founding work of German sociology, Ferdinand Tönnies’ Gemeinschaft und Gesellschaft, the political context in which historicist economics were transformed into sociology, explicit and implicit influences behind sociology in the writings of von Stein, Rodbertus, Wagner and Schmoller, the response of the ‘socialists of the lectern’ to Tönnies’ sociology, and differing responses to the debate between the historicist human sciences and rational theory.
Critical evaluation of on-engine fuel consumption measurement
Authors: Burke R D , Brace C J , Hawley J G
Published: June 2011

To enable continued development and facilitate the adoption of new internal combustion engine technologies, the accuracy and repeatability of measurement methods used for verification need to be improved upon. A variety of methods are available for the measurement of fuel consumption based on the volumetric or gravimetric principle or by equating carbon in the fuel to carbon in the exhaust flow. Measurements of fuel consumption from five different experimental campaigns with varying engine set-ups are presented, highlighting discrepancies between gravimetric fuel balance and exhaust feed gas carbon balance. Differences were larger for cold-start tests and if all correction factors are neglected offsets can reach 7 per cent.

The carbon balance and gravimetric methods have been considered independently to identify sources of inaccuracy and improvements have been suggested in the form of correction factors. The carbon balance estimate is dependent on a number of separate measurements, all taken at different conditions. To account for these, two correction factors were compared, the first proposed by the British Standards Institution and the second derived from the experimental conditions of each of the measurements. The gravimetric measurement was affected by changes in fuel temperature within the fuelling circuit and a corrective method was proposed based on the change in fuel density.

When correction factors were applied to each of the measurement techniques for the five experimental campaigns, discrepancies were less than 1 per cent, which, in most cases, was small enough for there to be no statistically significant difference between measurements. In addition, in some cases the scatter of results was reduced, contributing to improved test-to-test repeatability. The improved performance when using correction factors was explained by including known disturbances, such as fuel temperature and ambient humidity, as inputs to the measurement system.
Nonlinear controller of an air-cushion system for a swamp terrain vehicle: fuzzy logic approach
Authors: Hossain A , Rahman A , Mohiuddin A K M
Published: June 2011

This paper presents the fuzzy logic controller (FLC) of an air-cushion system for a swamp peat terrain vehicle and describes the process by which it functions. Cushion pressure is controlled by an electronic proportional control valve and FLC using the output signal of the distance (height) measuring sensor that was attached to the vehicle. The main purpose of this study was to develop a control scheme for an air-cushion system and to investigate the relationship between vehicle vertical position and the air-cushion system, and to illustrate the important role of the fuzzy logic control system. Experimental values were recorded in the laboratory for control system testing, and in the swamp peat terrain field for vehicle performance investigation. In this paper, a fuzzy logic expert system (FLES) model, based on the Mamdani approach, was developed to predict the changes in flowrate. The mean relative error of actual and predicted values from the FLES model of flowrate was found to be slightly above the acceptable limit. The goodness of fit of the prediction values from the FLES model was found to be close to 1.0 as expected, and hence demonstrated the good performance of the developed system.
Modelling shattered rim cracking in railroad wheels
Authors: Sura V , Mahadevan S
Published: June 2011

Shattered rim cracking, propagation of a subsurface crack parallel to the tread surface, is one of the dominant railroad wheel failure types observed in North America. This crack initiation and propagation life depends on several factors, such as wheel rim thickness, wheel load, residual stresses in the rim, and the size and location of material defects in the rim. This article investigates the effect of the above-mentioned parameters on shattered rim cracking, using finite element analysis and fracture mechanics. This cracking is modelled using a three-dimensional, multiresolution, elastic–plastic finite element model of a railroad wheel. Material defects are modelled as mathematically sharp cracks. Rolling contact loading is simulated by applying the wheel load on the tread surface over a Hertzian contact area. The equivalent stress intensity factor ranges at the subsurface crack tips are estimated using uni-modal stress intensity factors obtained from the finite element analysis and a mixed-mode crack growth model. The residual stress and wheel wear effects are also included in modelling shattered rim cracking. The analysis results show that the sensitive depth below the tread surface for shattered rim cracking ranges from 19.05 to 22.23 mm, which is in good agreement with field observations. The relationship of the equivalent stress intensity factor (Δ K eq) at the crack tip to the load magnitude is observed to be approximately linear. The analysis results show that the equivalent stress intensity factor (Δ K eq) at the crack tip depends significantly on the residual stress state in the wheel. Consideration of as-manufactured residual stresses decreases the Δ K eq at the crack tip by about 40 per cent compared to that of no residual stress state, whereas consideration of service-induced residual stresses increases the Δ K eq at the crack tip by about 50 per cent compared to that of as-manufactured residual stress state. In summary, the methodology developed in this article can help to predict whether a shattered rim crack will propagate for a given set of parameters, such as load magnitude, rim thickness, crack size, crack location, and residual stress state.
Unmanned air vehicle air data estimation using a matrix of pressure sensors: a comparison of neural networks and look-up tables
Authors: Samy I , Postlethwaite I , Gu D-W
Published: June 2011

Flush airdata sensing (FADS) systems are cost- and weight- effective alternatives to current air data booms for measuring important air data parameters such as airspeed, angle of attack, sideslip, etc. Most applications consider large manned/unmanned air vehicles where the Pitot-static tube is located at the nose tip. However, traditional air data booms can be physically impractical for micro- (unmanned) air vehicles (MAVs) and, in this article, a FADS system mounted on the wing leading edge of a MAV flown at low speeds of Mach 0.07 (wind tunnel experiments under corresponding conditions) is designed. Moreover, two approaches for converting the FADS system pressure to meaningful air data are compared: a neural network (NN) approach and a look-up table (LUT). Results have shown that instrumentation weight and cost were reduced by 80 per cent and 97 per cent, respectively, in comparison to a traditional air data boom. Overall, the NN estimation accuracies were 0.51°, 0.44 lb/ft2, and 0.62 m/s and the LUT estimation accuracies 1.32°, 0.11 lb/ft2, and 0.88 m/s for the angle of attack, static pressure, and airspeed, respectively. It was also found that the LUT has faster execution times while the NN was in most cases more robust to sensor faults. However, while the LUT requires high memory usage, especially for higher dimensions, the NN can be executed in a few lines of code.
Robust sliding mode control for spacecraft global fast-tracking manoeuvre
Authors: Wu S-N , Sun X-Y , Sun Z-W , Chen C-C
Published: June 2011

This article studies spacecraft attitude control problem to achieve global fast tracking for ground target. The expected spacecraft attitude parameters and a Lagrange-like model of spacecraft attitude motion are presented, respectively, and then a robust sliding mode controller based on this model and Euler parameters is designed to achieve tracking in the presence of model uncertainties and external disturbances. The proposed controller can guarantee global fast stability of the closed-loop systems and convergence of tracking errors by employing global fast-sliding mode model, which combines the advantages of linear and terminal sliding mode controls. The theoretical proof of stability and convergence is given subsequently. Numerical simulations are finally presented to demonstrate the performance of the developed controller.
Single flexion-axis selection influences femoral component alignment and kinematics during knee simulation
Authors: DesJardins JD , Rusly RJ
Published: June 2011

The objective of this paper is to investigate the effect of the implant geometry and alignment on its surface displacement, and to show that the proposed method of alignment can be used to improve the consistency of total knee replacement alignment for knee simulation. Poor femoral flexion-axis selection in the alignment process can possibly alter the intended design's functionality and introduce significant anterior/posterior (A/P), and proximal/distal (P/D) displacements. In the study, four multi-axis femoral components from each of two different manufacturers, NKII and 3DKnee, were used. A custom-built femoral alignment and surface measurement instrument was used to adjust and locate the single femoral axis position for each implant, which would optimally minimize their P/D displacements and A/P translations. The aligned NKII implants yielded a mean implant maximum P/D and A/P contact point shifts of 0.577 ± 0.078 mm (± std. dev.) and of 2.325 ± 0.243 mm between 0 and 60° of flexion, which was significantly different from the aligned 3DKnee, 0.415 ± 0.157 mm and 0.800 ± 0.1512 mm ( p < 0.0001, p < 0.0001). Future work is needed to quantify the effect of femoral flexion axis selection on resulting long-term wear, damage areas, and soft tissue loading during simulation.
Wear and surface analysis of 38 mm ceramic-on-metal total hip replacements under standard and severe wear testing conditions
Authors: Williams S R , Wu J J , Unsworth A , Khan I
Published: June 2011

The purpose of this study was to compare the wear of zirconia-toughened alumina (ZTA) and alumina femoral heads tested against as-cast CoCrMo alloy acetabular cups under both standard and severe wear conditions. A new severe test, which included medio-lateral displacement of the head and rim impact upon relocation, was developed. This resulted in an area of metal transfer and an area of increased wear on the superior-anterior segment of the head that were thought to be due to dislocation and rim impact respectively. While the wear of all ceramic heads was immeasurable using the gravimetric method, the wear rates for the metallic cups from each test were readily calculated. An average steady state wear rate of 0.023 ± 0.005 mm3/106 cycles was found for the cups articulating against ZTA under standard wear conditions. A similar result had previously been obtained for the wear of cups articulated against alumina heads of the same size (within the same laboratory). Under severe wear conditions an increase in the metallic cup steady state wear rate was found with the ZTA and alumina tests giving 0.623 ± 0.252 and 1.35 ± 0.154 mm3/106 cycles respectively. Wear of the ceramic heads was detected using atomic force microscopy which showed, under severe wear conditions, a decrease in polishing marks and occasional grain removal. The surfaces of the ZTA heads tested under standard conditions were virtually unchanged from the unworn samples. Friction tests showed low friction factors for all components, pre and post wear.
An investigation into the effect of weld technique on the residual stress distribution of 3CR12 (DIN 1.4003) built-up structural sections
Authors: Klopper J J , Laubscher R F , Steuwer A , James M N
Published: June 2011

This article presents an experimental investigation of thermally induced residual stresses in fabricated 3CR12 (DIN 1.4003) T-sections. 3CR12 is a weldable utility stainless steel developed to provide a superior alternative to coated carbon steels and other alloys which have a poor corrosion/abrasion resistance. Because of the difficulty and costs involved in hot-rolling stainless steel structural sections, they are usually fabricated by welding. In this investigation, full-penetration laser- and manual metal arc (MMA) joints were considered along with partial-penetrated MMA- and metal inert gas (MIG) welded joints. The residual stresses induced during welding were measured by neutron diffraction. All the sections displayed a largely tensile residual stress field around the weld that subsequently implied a compressive residual stress field in the flange regions. This was most pronounced for the MMA and MIG welds. The laser-welded sections displayed a more localized tensile residual stress field in the heat-affected zone that translated to lower average stresses in the flanges. In the latter part of this article, the effect of the weld-induced residual stress fields on the structural performance of appropriate T-section-based columns are assessed and compared. A significant difference in structural performance between the different weld techniques is predicted with the laser-welded sections displaying the highest predicted strength.
Fertility and Intergroup Bias in Racial and Minimal-Group Contexts
Authors: McDonald Melissa M. , Asher Benjamin D. , Kerr Norbert L. , Navarrete Carlos David
Published: June 2011

Recent research has shown that White women’s bias against Black men increases with elevated fertility across the menstrual cycle. We demonstrate that the association between fertility and intergroup bias is not limited to groups defined by race, but extends to group categories that are minimally defined, and may depend on the extent to which women associate out-group men with physical formidability. In Study 1, Black and White women with strong associations between the racial out-group and physical formidability displayed greater bias against out-group men as conception risk increased. Study 2 replicated these results in a minimal-group paradigm. These findings are consistent with the notion that women may be endowed with a psychological system that generates intergroup bias via mechanisms that rely on categorization heuristics and perceptions of the physical formidability of out-group men, particularly when the costs of sexual coercion are high.