bluuebunny/crossref_metadata_2025 huggingface dataset:
PARTIAL COMPLEMENTS IN FINITE GROUPS
Authors: CHEN INGRID
Published: June 2010

Let G be a finite group with normal subgroup N. A subgroup K of G is a partial complement of N in G if N and K intersect trivially. We study the partial complements of N in the following case: G is soluble, N is a product of minimal normal subgroups of G, N has a complement in G, and all such complements are G-conjugate.
On the ejection of Earth-mass planets from the habitable zones of the solar twins HD 20782 and HD 188015
Authors: Yeager K.E. , Eberle J. , Cuntz M.
Published: June 2010

We provide a detailed statistical study of the ejection of fictitious Earth-mass planets from the habitable zones of the solar twins HD 20782 and HD 188015. These systems possess a giant planet that crosses into the stellar habitable zone, thus effectively thwarting the possibility of habitable terrestrial planets. In the case of HD 188015, the orbit of the giant planet is essentially circular, whereas in the case of HD 20782, it is extremely elliptical. As starting positions for the giant planets, we consider both the apogee and perigee positions, whereas the starting positions of the Earth-mass planets are widely varied. For the giant planets, we consider models based on their minimum masses as well as models where the masses are increased by 30%. Our simulations indicate a large range of statistical properties concerning the ejection of the Earth-mass planets from the stellar habitable zones. For example, it is found that the ejection times for the Earth-mass planets from the habitable zones of HD 20782 and HD 188015, originally placed at the centre of the habitable zones, vary by a factor of ~200 and ~1500, respectively, depending on the starting positions of the giant and terrestrial planets. If the mass of the giant planet is increased by 30%, the variation in ejection time for HD 188015 increases to a factor of ~6000. However, the short survival times of any Earth-mass planets in these systems are of no surprise. It is noteworthy, however, that considerable differences in the survival times of the Earth-mass planets are found, which may be relevant for establishing guidelines of stability for systems with less intrusive giant planets.
Communicating imperceptible product attributes through traceability: A case study in an organic food supply chain
Authors: Lindh Helena , Olsson Annika
Published: June 2010

Companies in the food industry are driven to improve their traceability for several reasons. The primary reasons are food safety and quality. Another is the response to the increased interest among consumers in imperceptible product attributes such as organic, fair trade, dolphin-safe and non genetically modified (non-GMO). Such attributes are hard to distinguish and thus require generally enhanced traceability in order to verify their existence. This has led to an emergent area in which actors engage in gaining and maintaining traceability and communicating it to the consumers. This paper describes the relations between the actors in a supply chain (SC) in the field of organic food systems. It examines the objectives each actor has for gaining and maintaining traceability throughout the SC. The focus on organic relates to the challenge for the companies to ensure this imperceptible product attribute throughout the entire food system. A single case study was conducted in an organic food system providing organic ice cream products. The data collection included semi-structured interviews, observations, a review of internal documents and a survey among the participating companies. The findings illustrate and elaborate on the objectives companies have for engaging in traceability. The objectives identified are divided into three categories: food safety and quality, managing the SC and internal resources and communication with consumers. The survey confirms the results from the interviews that all actors want to engage in traceability. They prioritize the objectives differently, however. The study highlights the value of close relations between the actors when addressing consumer concerns regarding product and process characteristics, such as the imperceptible organic attribute.
Reaction Time and Brain Waves in Omitted Stimulus Tasks
Authors: Hernández Oscar H. , Vogel-Sprott Muriel
Published: June 2010

A missing stimulus task requires an immediate response to the omission of a regular recurrent stimulus. The task evokes a subclass of event-related potential known as omitted stimulus potential (OSP), which reflects some cognitive processes such as expectancy. The behavioral response to a missing stimulus is referred to as omitted stimulus reaction time (RT). This total RT measure is known to include cognitive and motor components. The cognitive component (premotor RT) is measured by the time from the missing stimulus until the onset of motor action. The motor RT component is measured by the time from the onset of muscle action until the completion of the response. Previous research showed that RT is faster to auditory than to visual stimuli, and that the premotor of RT to a missing auditory stimulus is correlated with the duration of an OSP. Although this observation suggests that similar cognitive processes might underlie these two measures, no research has tested this possibility. If similar cognitive processes are involved in the premotor RT and OSP duration, these two measures should be correlated in visual and somatosensory modalities, and the premotor RT to missing auditory stimuli should be fastest. This hypothesis was tested in 17 young male volunteers who performed a missing stimulus task, who were presented with trains of auditory, visual, and somatosensory stimuli and the OSP and RT measures were recorded. The results showed that premotor RT and OSP duration were consistently related, and that both measures were shorter with respect to auditory stimuli than to visual or somatosensory stimuli. This provides the first evidence that the premotor RT is related to an attribute of the OSP in all three sensory modalities.
Trial-to-Trial Variability in Evoked Neural Responses Exhibits a Very Low Frequency Temporal Signature
Authors: Demanuele C. , Capilla A. , Pérez Hernández E. , Sonuga-Barke E. J. S. , James C.
Published: June 2010

In functional magnetic resonance (fMRI) studies, the blood oxygen level dependent (BOLD) signal displays intrinsic spontaneous and task-independent very low frequency (VLF) oscillations (< 0.1 Hz). Most prominent during rest, when they persist into task sessions they can predict trial-to-trial variability in both evoked behavior and brain responses by providing a baseline onto which deterministic responses elicited by the task are superimposed. Moreover, evidence in the literature tentatively suggests that this VLF activity may not be present in the data as distinct, independent source(s) per se, but rather as a mechanism that modulates and perhaps even governs underlying brain processes. Here, we use electrophysiology to investigate the intertrial variability observed in magnetoencephalographic (MEG) event-related field (ERF) components, and to examine whether this variability exhibits a VLF time signature in order to indirectly infer information about the underlying slow waves. The focus is on the visual component, the M100, understood to be regulated by attention. We also explored whether individual differences in the M100 VLF pattern varies as a function of attention deficit/hyperactivity disorder (ADHD) by comparing 11 cases against 11 controls. The M100 component was extracted from the data using a recently introduced blind-source separation technique – space-time independent component analysis (ST-ICA) – which allowed trial-by-trial analysis to be performed on the M100 for proper assessment of VLF modulation. Our results demonstrate, for the first time, the ability of this signal-processing method to isolate relevant components from multidimensional, noisy, ERF data recorded from a highly dense 148-channel MEG system. The intertrial variability in the amplitude and latency of the M100 responses exhibits a slow wave pattern (< 0.1 Hz). However, there was no evidence that the degree of VLF modulation was different in ADHD participants. The role of this VLF activity in brain function is discussed.
Associations Between Self-Report of Emotional State and the EEG Patterns in Affective Disorders Patients
Authors: Wyczesany Miroslaw , Kaiser Jan , Coenen Anton M. L.
Published: June 2010

The study determines the associations between self-report of ongoing emotional state and EEG patterns. A group of 31 hospitalized patients were enrolled with three types of diagnosis: major depressive disorder, manic episode of bipolar affective disorder, and nonaffective patients. The Thayer ADACL checklist, which yields two subjective dimensions, was used for the assessment of affective state: Energy Tiredness (ET) and Tension Calmness (TC). Quantitative analysis of EEG was based on EEG spectral power and laterality coefficient (LC). Only the ET scale showed relationships with the laterality coefficient. The high-energy group showed right shift of activity in frontocentral and posterior areas visible in alpha and beta range, respectively. No effect of ET estimation on prefrontal asymmetry was observed. For the TC scale, an estimation of high tension was related to right prefrontal dominance and right posterior activation in beta1 band. Also, decrease of alpha2 power together with increase of beta2 power was observed over the entire scalp.
Effects of Stimuli on Cardiovascular Reactivity Occurring at Regular Intervals During Mental Stress
Authors: Lackner Helmut Karl , Goswami Nandu , Hinghofer-Szalkay Helmut , Papousek Ilona , Scharfetter Hermann , Furlan Rafaello , Schwaberger Guenther
Published: June 2010

Studies examining the direct effects of stimuli needed to perform mental stress tasks such as instructor commands at regular intervals during the mental task are limited to date. Because of the comprehensive effects of different stimuli, we studied the effect of short instructor commands occurring at regular intervals on the behavior of the cardiovascular system during two different types of tasks. Continuous beat-to-beat heart rate and blood pressure, respiration, thoracic impedance, skin conductance, and peripheral temperature were measured in 20 healthy females during a cancellation test of attention (stimuli interval of 20 s) and during mental arithmetic tasks (stimuli interval of 120 s). The transient effects of the stimuli on measures in the time domain as well as the effects of stimulus intervals on measures in the frequency domain (using spectral analysis) were examined. Instructor commands caused increases in several cardiovascular variables and in skin conductance. SBP (systolic blood pressure) and DBP (diastolic blood pressure) showed a significant stimulus response only during the mental arithmetic tasks. An effect of instructor commands at regular intervals was seen in the spectral analysis at 0.05 Hz (cancellation test of attention) and 1/120 Hz (mental arithmetic), according to the stimulus intervals of 20 s and 120 s used in these tasks. The findings suggest that even simple instructor commands given during high mental task load had a strong impact and can considerably influence measures of cardiovascular reactivity. The effects of paced stimuli should be considered when interpreting cardiovascular responses to task conditions with constant stimulus intervals.
Construct Validity of the Fear of Negative Appearance Evaluation Scale in a Community Sample of French Adolescents
Authors: Maïano Christophe , Morin Alexandre J.S. , Monthuy-Blanc Johana , Garbarino Jean-Marie
Published: June 2010

The main objective of the present series of studies was to test the construct validity (i.e., content, factorial, and convergent validities) of the Fear of Negative Appearance Evaluation Scale (FNAES) in a community sample of French adolescents. A total sample of 683 adolescents was involved in three studies. The factorial validity and the measurement invariance of the FNAES were verified through a series of confirmatory factor analyses. The convergent validity of the FNAES was then verified through correlational analyses. The first study showed that the content and formulation of the French FNAES items were adequate for children and adolescents. The following two studies (Studies 2 to 3) provided (a) support for the factor validity, reliability, and convergent validity of a five-item French version of the FNAES, and (b) partial support for the measurement invariance of the resulting FNAES across genders. However, the latent mean structure of the FNAES did not prove to be invariant across genders, revealing a significantly higher latent mean score of FNAES in girls relative to boys. The present results, thus, provide preliminary evidence regarding the construct validity of the FNAES in a community sample of French adolescents. Recommendations for future practice and research regarding this instrument are outlined.
A Psychometric Study of the Geriatric Depression Scale
Authors: Lopez Michael N. , Quan Nancy M. , Carvajal Perla M.
Published: June 2010

Criterion-referenced (Livingston’s r) and norm-referenced (Cronbach’s α and Gilmer-Feldt coefficient) techniques were used to calculate the internal consistency reliability of the 30-item Geriatric Depression Scale (GDS) on a sample (N = 417) of elderly medical outpatients. For the widely used cutoff score of 10 for depression, the criterion-referenced reliability (Livingston’s r) of the GDS total score was found to be .896, .883, and .891 for the elderly patients with Mini Mental State Examination (MMSE) scores > 17, ≤ 17, and total sample, respectively, while the norm-referenced reliability Gilmer-Feldt coefficient (and Cronbach’s α) of the GDS total score was found to be .895 (α = .893), .877 (α = .875), and .890 (α = .888), respectively. Tests of significance between the GDS total score means and reliability coefficients for the patients with MMSE scores > 17 and ≤ 17 were found to be nonsignificant. Therefore, the cognitive status of our sample does not seem to have an effect on the GDS total score. Item-total score correlations showed that 29 out of the 30 GDS items were good discriminators. The use of true score confidence intervals around GDS observed scores is recommended when used to make decisions about depression in the elderly.
An Italian Adaptation of the Emotion Regulation Questionnaire
Authors: Balzarotti Stefania , John Oliver P. , Gross James J.
Published: June 2010

The goal of this research was to develop and validate an Italian version of the Emotion Regulation Questionnaire (ERQ, Gross & John, 2003 ). In an Italian undergraduate sample (N = 416), the two-scale ERQ structure was confirmed by confirmatory factor analysis, and each of the two scales (Reappraisal and Suppression) showed good internal consistency. The Italian ERQ also showed the predicted associations with measures of coping, affect, personality, and social functioning. Specifically, Reappraisal was positively correlated with positive reinterpretation, positive affect, and extraversion, and negatively correlated with negative affect and neuroticism. Suppression, by contrast, was negatively correlated with the venting of emotions, positive affect, extraversion, social support and social diversion. Taken together, these findings suggest that the Italian ERQ is a reliable and valid measure that inherits the nomological network of associations from the original version of the ERQ.
Autonomy and Workload in Relation to Temporary and Permanent Workers’ Job Involvement
Authors: De Cuyper Nele , Mauno Saija , Kinnunen Ulla , De Witte Hans , Mäkikangas Anne , Nätti Jouko
Published: June 2010

The aim of the study was to investigate contract type (temporary vs. permanent employment) as a possible moderator in the relationship between autonomy and workload on the one hand, and job involvement on the other hand in samples from two countries: Belgium and Finland. The results on possible interactions were similar in the two countries. Contract type moderated the relationship between autonomy and job involvement: The relationship was stronger in permanent than in temporary workers. No moderation was found for workload. Instead, workload associated positively with job involvement in both temporary and permanent workers. These findings are discussed with reference to the activation hypothesis as implied in the Job Demand-Control Model and earlier insights from psychological contract theory and research.
Gathering Behavioral Samples Through a Computerized and Standardized Assessment Center Exercise
Authors: Lievens Filip , Van Keer Etienne , Volckaert Ellen
Published: June 2010

Although computerization and standardization might make assessment center (AC) exercises easier to administer and score, drawbacks are that most of such exercises have a static and multiple-choice format. This study reports on the development and initial validation of a computerized and standardized AC exercise that simulates key managerial tasks. This AC exercise capitalizes not only on the benefits of computerization and standardization (efficiency and cost savings) but at the same time aims to avoid their usual drawbacks (lower response fidelity and interactivity). The composite exercise score was significantly related to several criteria of interest and had incremental validity beyond cognitive ability. The exercise was also significantly related to candidates’ people management competencies.
Regional and teleseismic analysis of underground nuclear explosion waveforms and constraints for shear wave excitation mechanisms
Authors: Hong Tae‐Kyung
Published: June 2010

Regional and teleseismic waveforms of underground nuclear explosions (UNEs) at the Balapan and the Nevada test sites are analyzed to understand the nature of shear waves excited from UNEs. The phase composition of wavefields in the source and receiver regions is examined using a source array frequency‐wave‐number analysis and polarization analyses. It is observed that regional mantle‐lid shear waves, Sn, often develop strongly. On the other hand, observed teleseismic shear waves from UNEs are much weaker than those from earthquakes. Source array analyses of the shear waves from UNEs display coherent energy that is polarized in a certain azimuthal direction. The observation of coherent shear energy in different UNEs suggests that the shear energy is excited in a consistent manner at every UNE. We constrain the dominant shear wave excitation mechanism from the observed shear wave features. The observations appear to be consistent with the tectonic release model with conical rock cracking.
Building the central Andes through axial lower crustal flow
Authors: Ouimet William B. , Cook Kristen L.
Published: June 2010

The orogen‐scale morphology of the central Andes, which are longitudinally symmetric at ∼19°S, correlates with the modern geometry of the subducting Nazca slab but is largely independent of local bedrock geology or precipitation. Crustal thickness, as measured by the cross‐strike width of the orogen above 3000 m and the cross‐sectional area of the crust, is not well correlated with observed magnitudes of upper crustal shortening. In our interpretation, the large‐scale morphology is instead correlated with and controlled by lithospheric‐scale processes and subduction dynamics. Using a semianalytic, three‐dimensional Newtonian viscous flow model, we produce Andean‐like topography and distribution of upper crustal shortening during subduction of an oceanic lithosphere eastward beneath the Andes provided that (1) the more steeply dipping slab segment beneath the central Andes is overlain by the weak lower or middle crust, (2) the flat slab subduction segments to the north and south of this zone are overlain by the strong middle and lower crust, and (3) the steeply dipping central slab segment is overlain by a narrow, centrally localized zone of increased crustal shortening. The resulting model orogen displays substantial orogen‐parallel flow in the weak lower crust above the steep slab zone. Orogen‐parallel flow does not penetrate into the regions of stronger lower crust above the flat slab segments, resulting in a broad, plateau‐topped orogen above the central slab segment and narrow but high orogenic segments above the flat slab region. Redistribution of material through lower crust flow can account for the observed mismatch between crustal volume and upper crustal shortening in the central Andes and may explain young (<10 Ma) crustal thickening and surface uplift that has been argued for in some regions.
Crustal‐scale pure shear foreland deformation of western Argentina
Authors: Meigs Andrew J. , Nabelek John
Published: June 2010

New analyses of teleseismic body waves from moderate earthquakes in western Argentina demonstrate that active shortening of the Andean foreland occurs on reverse faults extending to 40–50 km depth. Existing crustal‐scale models of foreland deformation invoke thin‐skinned fault geometries, which root into an east‐dipping mid‐crustal décollement. Whereas thin‐skinned thrust sheets dominate shallow‐crustal structure, seismological and geological data illustrate that planar reverse faults and pure‐shear deformation involving more than 75% of the crust characterizes this thick‐skinned structural province.
Electron holes and heating in the reconnection dissipation region
Authors: Che H. , Drake J. F. , Swisdak M. , Yoon P. H.
Published: June 2010

Using particle‐in‐cell simulations and kinetic theory, we explore the current‐driven turbulence and associated electron heating in the dissipation region during 3D magnetic reconnection with a guide field. At late time the turbulence is dominated by the Buneman and lower hybrid instabilities. Both produce electron holes that co‐exist but have very different propagation speeds. The associated scattering of electrons by the holes enhances electron heating in the dissipation region.
Video Games in Health Care: Closing the Gap
Authors: Kato Pamela M.
Published: June 2010

Although a great deal of media attention has been given to the negative effects of playing video games, relatively less attention has been paid to the positive effects of engaging in this activity. Video games in health care provide ample examples of innovative ways to use existing commercial games for health improvement or surgical training. Tailor-made games help patients be more adherent to treatment regimens and train doctors how to manage patients in different clinical situations. In this review, examples in the scientific literature of commercially available and tailor-made games used for education and training with patients and medical students and doctors are summarized. There is a history of using video games with patients from the early days of gaming in the 1980s, and this has evolved into a focus on making tailor-made games for different disease groups, which have been evaluated in scientific trials more recently. Commercial video games have been of interest regarding their impact on surgical skill. More recently, some basic computer games have been developed and evaluated that train doctors in clinical skills. The studies presented in this article represent a body of work outlining positive effects of playing video games in the area of health care.
Video Games and Spatial Cognition
Authors: Spence Ian , Feng Jing
Published: June 2010

Video game enthusiasts spend many hours at play, and this intense activity has the potential to alter both brain and behavior. We review studies that investigate the ability of video games to modify processes in spatial cognition. We outline the initial stages of research into the underlying mechanisms of learning, and we also consider possible applications of this new knowledge. Several experiments have shown that playing action games induces changes in a number of sensory, perceptual, and attentional abilities that are important for many tasks in spatial cognition. These basic capacities include contrast sensitivity, spatial resolution, the attentional visual field, enumeration, multiple object tracking, and visuomotor coordination and speed. In addition to altering performance on basic tasks, playing action video games has a beneficial effect on more complex spatial tasks such as mental rotation, thus demonstrating that learning generalizes far beyond the training activities in the game. Far transfer of this sort is generally elusive in learning, and we discuss some early attempts to elucidate the brain functions that are responsible. Finally, we suggest that studying video games may contribute not only to an improved understanding of the mechanisms of learning but may also offer new approaches to teaching spatial skills.
Accuracy of Self‐Reported Energy Intakes in Low‐Income Urban 4th Grade Minority Children
Authors: Garcia‐Dominic Oralia , Wray Linda A. , Ledikwe Jenny H. , Mitchell Diane C. , Ventura Alison K. , Hernandez Arthur E. , Yin Zenong , Trevino Roberto P. , Ulbrecht Jan S.
Published: June 2010

We examined the accuracy of self‐reported energy intake (rEI) in low‐income, urban minority school‐aged children at risk for obesity and associated diabetes utilizing a relatively new, simple previously published prediction equation for identifying inaccurate reports of dietary energy intake. Participants included 614 nine‐year‐old boys (51%) and girls (49%). Three 24‐h dietary recalls were collected. Children's height, weight (used to calculate BMI), and percent body fat (%BF) were measured. Physical fitness, reported family history of diabetes, and ethnicity were also collected. A previously published prediction equation was used to determine the validity of rEIs in these children to identify under‐, plausible‐, and over‐reporters. Additionally, we examined the question of whether there is a difference in reporting by sex, ethnicity, BMI, and %BF. On average, 18% of the children were at risk of being overweight, 43% were already overweight at baseline, yet these children reported consuming fewer calories on average than recommended guidelines. Additionally, reported caloric intake in this cohort was negatively associated with BMI and %BF. Using the previously described methods, 49% of participants were identified as under‐reporters, whereas 39 and 12% were identified as plausible‐ and over‐reporters, respectively. On average, children reported caloric intakes that were almost 100% of predicted energy requirement (pER) when the sedentary category was assigned. Inactivity and excessive energy intake are important contributors to obesity. With the rising rates of obesity and diabetes in children, accurate measures of energy intake are needed for better understanding of the relationship between energy intake and health outcomes.
Benefits of Adaptive FM Systems on Speech Recognition in Noise for Listeners Who Use Hearing Aids
Authors: Thibodeau Linda
Published: June 2010

Purpose

To compare the benefits of adaptive FM and fixed FM systems through measurement of speech recognition in noise with adults and students in clinical and real-world settings.

Method

Five adults and 5 students with moderate-to-severe hearing loss completed objective and subjective speech recognition in noise measures with the 2 types of FM processing. Sentence recognition was evaluated in a classroom for 5 competing noise levels ranging from 54 to 80 dBA while the FM microphone was positioned 6 in. from the signal loudspeaker to receive input at 84 dB SPL. The subjective measures included 2 classroom activities and 6 auditory lessons in a noisy, public aquarium.

Results

On the objective measures, adaptive FM processing resulted in significantly better speech recognition in noise than fixed FM processing for 68- and 73-dBA noise levels. On the subjective measures, all individuals preferred adaptive over fixed processing for half of the activities. Adaptive processing was also preferred by most (8–9) individuals for the remaining 4 activities.

Conclusion

The adaptive FM processing resulted in significant improvements at the higher noise levels and was preferred by the majority of participants in most of the conditions.
Prevalence and Risk Factors of Hearing Impairment Among Primary-School Children in Shebin El-Kom District, Egypt
Authors: Taha Azza A. , Pratt Sheila R. , Farahat Taghreed M. , Abdel-Rasoul Gaafar M. , Albtanony Manal A. , Elrashiedy Abdel-Latif E. , Alwakeel Hany R. , Zein Ahmed
Published: June 2010

Purpose

This study examined the feasibility of screening hearing loss in rural and urban schools in Egypt, and investigated the prevalence and causes of hearing impairment (HI) in Egyptian primary-school students.

Method

A total of 555 children (6–12 years of age) from a rural and an urban school in the Shebin El-Kom District of Egypt were screened for HI at their schools. A 2-stage screening procedure was used, and positive cases were referred for a diagnostic hearing assessment at a regional medical facility. Risk factors were investigated through a parent questionnaire and an environmental study consisting of noise, ventilation, and crowding measurements at the schools.

Results

The screening failure rate was 25.6%, and the prevalence of confirmed HI was 20.9%. The rate of HI did not differ across the schools. Conductive hearing loss of minimal to mild severity was the most common type of HI. The most important predictors for HI were parent suspicion, otitis media, household smoking, low socioeconomic status, and postnatal jaundice.

Conclusions

The prevalence of HI did not differ across settings and was more common than reported in children from developed countries. The screening results also suggest that professionals with limited audiology background can be trained to implement hearing screening programs in Egyptian schools.
YouTube™ in the Speech-Language Pathology Classroom
Authors: Manasco M. Hunter
Published: June 2010

YouTube™ is an online video sharing Web site that is increasingly used in higher education classrooms. In addition presenting content on many diverse topics, YouTube™ rapidly became a rich source of clinical illustrations with relevance for the speech-language pathology classroom. Although professors in health education now take advantage of this resource, no documentation exists regarding students' reactions to the use of YouTube™ in the classroom. The purpose of this study was to survey students' opinions regarding the use of YouTube™ in the classroom. Videos from YouTube™ augmented lecture material in four speech-language pathology classrooms. At the end of the semester, students rated their opinions of the professor’s use of YouTube™ in the classroom and the contribution of the Web site to their classroom experience. All 104 students in the classes surveyed responded. A majority of students reported increased understanding, interest in, and retention of the classroom material due to use of videos on YouTube™.
Designing Our Courses for Greater Student Engagement and Better Student Learning
Authors: Dee Fink L.
Published: June 2010

One of the major tasks we perform as teachers is to design our courses. This refers to all the decisions that we make about how we want the course to unfold for our students. If we do this right, the chances of getting greater student engagement and better student learning are significantly higher. This article contains a description of Integrated Course Design, a particular, learning-centered way of designing our courses. It begins by asking us to identify a range of important kinds of learning we want our students to achieve. Then, the teacher identifies appropriate learning and assessment activities.
Study of the influence of vane angle on shaft output of a multivane air turbine
Authors: Singh Bharat Raj , Singh Onkar
Published: June 2010

Faster consumption of hydrocarbon fuel in the transport sector is posing global threat of depletion of fossil fuel reserves. Studies are being extensively done to search for an alternative energy source and/or to find out appropriate energy conversion system. Among various alternatives, the use of compressed atmospheric air in air turbine is an attractive option provided the atmospheric air is compressed by natural sources such as sun energy, wind energy, etc. It has the capability to produce shaft work with almost zero pollution in the environment. This paper details the mathematical modeling of a small capacity compressed air driven multivane air turbine. The effect of having different vane angles and inlet pressure on shaft work output has been studied and analyzed here. The study shows that the flow work has significant contribution in total work output and varies from 1.5% to 16.3% at different pressures, 2–6 bars, and injection angles, 30°–60°. The total shaft work is found to be maximum at vane angle θ=36° (ten vanes) when injection angle is kept at 60°, and it reduces at vane angle θ=45° (eight vanes) when injection angle is kept at 45° and further goes down at vane angle θ=60° (six vanes) when injection angle is 30°, if injection pressure is maintained at 6 bars and speed of rotation at 2500 rpm.
Ultrathin gate-contacts for metal-semiconductor field-effect transistor devices: An alternative approach in transparent electronics
Authors: Frenzel H. , Lajn A. , von Wenckstern H. , Grundmann M.
Published: June 2010

Transparent metal-insulator-semiconductor field-effect transistors (TMISFETs) are commonly designated as one keystone of transparent circuitry. TMISFETs were demonstrated using carbon nanotubes, organics, or oxides. The optimization of their gate-insulator as well as the field-effect mobility and switching voltages is of major interest in this research field. We present an alternative approach based on metal-semiconductor field-effect transistors (MESFETs) circumventing these problems of TMISFET technology. We use ultrathin transparent rectifying contacts (TRCs) consisting of non-insulating AgxO or PtxO layers and a highly conducting capping layer realized by room-temperature sputtering. The process is compatible with other low-temperature, low-cost manufacturing steps. We demonstrate the potential of such TRCs for ZnO-based MESFETs having a transparency of 70% in the visible, on/off-ratios higher than 106 within a gate-voltage sweep of only 2.7 V and mobilities up to 12 cm2/V s. Inverters fabricated from these transistors exhibit maximum gain of 196 and uncertainty level of 0.36 V, outperforming inverters based on TMISFETs.
Comment on “Dynamics of an electron driven by relativistically intense laser radiation” [Phys. Plasmas 15, 023104 (2008)]
Authors: Tian Youwei , Bao Gang , Zheng Ying , Yang Jianping , Yu Wei , Wang Xin
Published: June 2010

Galkin et al. [Phys. Plasmas 15, 023104 (2008)] presented the comparison of the electron dynamics in the cases of the linear and circular polarizations of the optical fields. They assume that the longitudinal component of the laser field can be neglected in the case of longitudinal displacement less than the Rayleigh range. In this comment, we point out that the longitudinal component must be considered for the minimum spot size less than 10 times wavelength for linearly polarized laser pulse and for the minimum spot size less than 15 times wavelength for circularly polarized laser pulse.
Response to “Comment on ‘Dynamics of an electron driven by relativistically intense laser radiation’ ” [Phys. Plasmas 17, 064701 (2010)]
Authors: Galkin A. L. , Korobkin V. V. , Romanovsky M. Yu. , Shiryaev O. B.
Published: June 2010

In a recent comment, Tian et al. [Phys. Plasmas 17, 064701 (2010)] reported a disagreement between their simulation results for the dynamics of an electron in a circularly polarized relativistically intense laser field and those presented in this paper. We demonstrate that the disagreement stems from certain inaccuracies in the analysis and the numerical simulation of the electron dynamics in the comment.
Improved measurement method for electron energy distribution functions with high accuracy and reliability
Authors: Bang Jin Young , Kim Aram , Chung Chin Wook
Published: June 2010

An improved ac superimposed method for measuring the electron energy distribution function (EEDF) with high accuracy is proposed. Although high amplitude of the superimposed ac voltage provides a higher signal-to-noise ratio (SNR), it causes the distortion in the EEDF. To correct the distortion, we used two different EEDFs measured by applying two different amplitudes. The distortion was accurately corrected over the entire electron energy region, and the corrected EEDF had the better SNR. The reliability of the corrected EEDF was proved by comparing the effective electron temperatures obtained from the measured EEDFs, and as a result, the corrected EEDF was very reliable.
A 12.5 GHz-spaced optical frequency comb spanning >400 nm for near-infrared astronomical spectrograph calibration
Authors: Quinlan F. , Ycas G. , Osterman S. , Diddams S. A.
Published: June 2010

A 12.5 GHz-spaced optical frequency comb locked to a global positioning system disciplined oscillator for near-infrared (IR) spectrograph calibration is presented. The comb is generated via filtering a 250 MHz-spaced comb. Subsequent nonlinear broadening of the 12.5 GHz comb extends the wavelength range to cover 1380–1820 nm, providing complete coverage over the H-band transmission window of earth’s atmosphere. Finite suppression of spurious sidemodes, optical linewidth, and instability of the comb has been examined to estimate potential wavelength biases in spectrograph calibration. Sidemode suppression varies between 20 and 45 dB, and the optical linewidth is ∼350 kHz at 1550 nm. The comb frequency uncertainty is bounded by ±30 kHz (corresponding to a radial velocity of ±5 cm/s), limited by the global positioning system disciplined oscillator reference. These results indicate that this comb can readily support radial velocity measurements below 1 m/s in the near IR.
Mechanism of charge transport in poly(2,5-dimethoxyaniline)
Authors: Singh Rajiv K. , Kumar Amit , Singh Ramadhar
Published: June 2010

Poly(2,5-dimethoxyaniline) (PDMA) has been synthesized by chemical oxidative polymerization technique using varying ratio of oxidants; ferric chloride (FeCl3) and ammonium persulfate [(NH4)2S2O8], in an inert atmosphere at low temperature ∼278 K. The synthesized samples of PDMA have been characterized by Fourier transform infrared spectroscopy, scanning electron microscopy and by measuring its dc conductivity (σdc). The temperature dependence of dc conductivity of PDMA samples has been examined in the wide temperature range 6–303 K. The analysis of dc conductivity data reveals that in the temperature range ∼100–303 K, the dc conductivity is predominantly governed by Mott’s three-dimensional variable range hopping, however, below 100 K tunneling seems to dominate. Different Mott’s parameters such as characteristic temperature (T0), density of states at the Fermi level [N(EF)], the average hopping distance (R), and the average hopping energy (W) have been estimated for all the PDMA samples and are in good agreement with the values reported earlier for other conjugated polymers.
Low-threshold-current-density AlGaN-cladding-free m-plane InGaN/GaN laser diodes
Authors: Farrell R. M. , Hsu P. S. , Haeger D. A. , Fujito K. , DenBaars S. P. , Speck J. S. , Nakamura S.
Published: June 2010

We demonstrate AlGaN-cladding-free m-plane InGaN/GaN laser diodes with threshold current densities that are comparable to state-of-the-art c-plane InGaN/GaN laser diodes. Thick InGaN waveguiding layers and a relatively wide active region with three 8 nm quantum wells were used to provide adequate refractive index contrast with the GaN cladding layers, thus eliminating the need for AlGaN cladding layers. Despite the large active region volume, lasing was achieved at a threshold current density of 1.54 kA/cm2, suggesting that the realization of even lower threshold current densities should be possible by reducing the number of quantum wells in the active region.
Phase diagram of ferroelectric nanowires and its mechanical force controllability
Authors: Lin S. P. , Zheng Yue , Cai M. Q. , Wang Biao
Published: June 2010

A phenomenological thermodynamic model of ferroelectric nanowires is developed to investigate the size-temperature phase diagrams. Considering existence of the surface tension, size, and external applied stress effects, the approximated expressions of the transition temperatures at which the paraelectric phase loses its stability with respect to the appearance of the spontaneous polarization are derived. At the same time, the size-temperature phase diagrams as functions of the ferroelectric nanowire radius are obtained, and also show its external mechanical stress controllability.
Strength and elastic deformation of natural and synthetic diamond crystals shock compressed along [100]
Authors: Lang J. M. , Gupta Y. M.
Published: June 2010

Plane shock wave experiments were conducted to determine the strength and elastic response of natural and synthetic diamond single crystals shocked along [100] to peak elastic stresses of ∼90 and ∼120 GPa. Velocity interferometry was used to measure particle velocity histories and shock velocities in the diamond samples. The maximum elastic wave amplitudes (89±3 GPa) for both crystal types were comparable. This value corresponds to shear stresses of 30 and 35 GPa (∼G/15) for the (111) [11¯0] and (111) [21¯1¯] slip systems, respectively. Surprisingly, the elastic limit (57±3 GPa) was lower for the higher peak stress. The elastic constant C111 was experimentally determined to be −7804±653 GPa.
Upconversion of a relativistic Coulomb field terahertz pulse to the near infrared
Authors: Jamison S. P. , Berden G. , Phillips P. J. , Gillespie W. A. , MacLeod A. M.
Published: June 2010

We demonstrate the spectral upconversion of a unipolar subpicosecond terahertz (THz) pulse, where the THz pulse is the Coulomb field of a single relativistic electron bunch. The upconversion to the optical allows remotely located detection of long wavelength and nonpropagating components of the THz spectrum, as required for ultrafast electron bunch diagnostics. The upconversion of quasimonochromatic THz radiation has also been demonstrated, allowing the observation of distinct sum- and difference-frequency mixing components in the spectrum. Polarization dependence of first and second order sidebands at ωopt±ωTHz, and ωopt±2ωTHz, respectively, confirms the χ(2) frequency mixing mechanism.
Striated surface morphology and crystal orientation of m-plane GaN films grown on γ-LiAlO2(100)
Authors: Wang K. R. , Ramsteiner M. , Mauder C. , Wan Q. , Hentschel T. , Grahn H. T. , Kalisch H. , Heuken M. , Jansen R. H. , Trampert A.
Published: June 2010

Polarized in-plane and cross-sectional Raman spectra have been used to determine the crystal orientation of m-plane GaN grown on γ-LiAlO2(100) (LAO) using a three-step metalorganic vapor phase epitaxy process. The epitaxial relationship is found to be GaN(11¯00)∥LAO(100) and GaN[112¯0]∥LAO[001]. However, the stripes on the GaN surface are oriented parallel to [0001], i.e., perpendicular to the one found on striated m-plane GaN surfaces in previous studies. This unusual orientation is attributed to the changes in the Ga adatom kinetics due to the presence of a 2-nm-thick interlayer observed at the GaN/LAO interface in transmission electron microscopy.
Impact of interface controlling layer of Al2O3 for improving the retention behaviors of In–Ga–Zn oxide-based ferroelectric memory transistor
Authors: Yoon Sung-Min , Yang Shin-Hyuk , Jung Soon-Won , Byun Chun-Won , Park Sang-Hee Ko , Hwang Chi-Sun , Lee Gwang-Geun , Tokumitsu Eisuke , Ishiwara Hiroshi
Published: June 2010

We characterized the nonvolatile memory thin-film transistors, which was composed of an amorphous indium-gallium-zinc oxide (α-IGZO) active channel and a ferroelectric poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] gate insulator, and investigated the impact of an interface controlling layer. Excellent device performances, such as the field-effect mobility of 60.9 cm2 V−1 s−1, the subthreshold swing of 120 mV/dec, and the memory window of 6.4 V at ±12 V programming, were confirmed for the device without any interface layer. However, the memory retention time was very short. The retention behaviors could be dramatically improved when 4 nm thick Al2O3 layer was introduced between the P(VDF-TrFE) and α-IGZO.
Tellurium assisted realization of p-type N-doped ZnO
Authors: Tang Kun , Gu Shulin , Wu Kongping , Zhu Shunming , Ye Jiandong , Zhang Rong , Zheng Youdou
Published: June 2010

In this paper, the authors demonstrate an effective pathway to enhance the p-type conduction in N-doped ZnO through codoping method with tellurium during metal-organic chemical vapor deposition process. Tellurium may act as a surfactant in reducing the formation energy of the NO acceptors and thus to enhance the incorporation efficiency of nitrogen. In addition, this codoping method shows a significant effect in suppressing the formation of donorlike carbon related complexes. The increased hole carrier concentration exhibits strong evidence to the enhancement of dopant solubility, and the Te–N codoping method provides an efficient technique for realizing p-type ZnO.
Exploring the Perceptual Causes of Search Set-Size Effects in Complex Scenes
Authors: Neider Mark B , Zelinsky Gregory J
Published: June 2010

We explored search set-size effects in the context of scenes, where objects are difficult to delineate and define. Observers searched for a tank target in landscape scenes populated by boulder, shrub, and tree distractors, which varied in their color and size similarity to the target. Scenes contained either 75 or 125 distractors. In two experiments we found that adding boulder or shrub distractors that were similar to the target in color and in size produced a consistent set-size effect, but adding distractors that were similar to the target only in size did not. Tree distractors, which were larger than the target, also produced a set-size effect regardless of whether they had a target-similar color (experiment 1) or not (experiment 2). In a third experiment we varied target-tree color similarity and tree color heterogeneity and found no change in search efficiency. We interpret these data as evidence for two independent sources of set-size effects in scenes, one subject to target–distractor similarity relationships (shrubs/boulders) and the other reflecting overall visual clutter (trees), with these latter clutter effects definable by edge content.
Visual Capture of Action, Experience of Ownership, and the Illusion of Self-Touch: A New Rubber Hand Paradigm
Authors: Davies Anne M Aimola , White Rebekah C , Thew Graham , Aimola Natalie M V , Davies Martin
Published: June 2010

A new rubber hand paradigm evokes an illusion with three conceptually distinct components: (i) the participant experiences her/his hidden right hand as administering touch at the location of the examiner's viewed administering hand (visual capture of action); (ii) the participant experiences the examiner's administering hand as being the participant's own hand (experience of ownership); and (iii) the participant experiences her/his two hands as being in contact, as if she/he were touching her/his own hand (illusion of self-touch). The presence of these illusory experiences was confirmed by questionnaire responses and proprioceptive drift data.