Hands-free administration of subjective workload scales: Acceptability in a surgical training environment

Introduction

Subjective workload measures are usually administered in a visual-manual format, either electronically or by paper and pencil. However, vocal responses to spoken queries may sometimes be preferable, for example when experimental manipulations require continuous manual responding or when participants have certain sensory/motor impairments. In the present study, we evaluated the acceptability of the hands-free administration of two subjective workload questionnaires - the NASA Task Load Index (NASA-TLX) and the Multiple Resources Questionnaire (MRQ) - in a surgical training environment where manual responding is often constrained.

Method

Sixty-four undergraduates performed fifteen 90-s trials of laparoscopic training tasks (five replications of 3 tasks - cannulation, ring transfer, and rope manipulation). Half of the participants provided workload ratings using a traditional paper-and-pencil version of the NASA-TLX and MRQ; the remainder used a vocal (hands-free) version of the questionnaires. A follow-up experiment extended the evaluation of the hands-free version to actual medical students in a Minimally Invasive Surgery (MIS) training facility.

Results

The NASA-TLX was scored in 2 ways - (1) the traditional procedure using participant-specific weights to combine its 6 subscales, and (2) a simplified procedure - the NASA Raw Task Load Index (NASA-RTLX) - using the unweighted mean of the subscale scores. Comparison of the scores obtained from the hands-free and written administration conditions yielded coefficients of equivalence of r = 0.85 (NASA-TLX) and r = 0.81 (NASA-RTLX). Equivalence estimates for the individual subscales ranged from r = 0.78 (“mental demand”) to r = 0.31 (“effort”). Both administration formats and scoring methods were equally sensitive to task and repetition effects. For the MRQ, the coefficient of equivalence for the hands-free and written versions was r = 0.96 when tested on undergraduates. However, the sensitivity of the hands-free MRQ to task demands (η_partial² = 0.138) was substantially less than that for the written version (η_partial² = 0.252). This potential shortcoming of the hands-free MRQ did not seem to generalize to medical students who showed robust task effects when using the hands-free MRQ (η_partial² = 0.396). A detailed analysis of the MRQ subscales also revealed differences that may be attributable to a “spillover” effect in which participants’ judgments about the demands of completing the questionnaires contaminated their judgments about the primary surgical training tasks.

Conclusion

Vocal versions of the NASA-TLX are acceptable alternatives to standard written formats when researchers wish to obtain global workload estimates. However, care should be used when interpreting the individual subscales if the object is to make comparisons between studies or conditions that use different administration modalities. For the MRQ, the vocal version was less sensitive to experimental manipulations than its written counterpart; however, when medical students rather than undergraduates used the vocal version, the instrument’s sensitivity increased well beyond that obtained with any other combination of administration modality and instrument in this study. Thus, the vocal version of the MRQ may be an acceptable workload assessment technique for selected populations, and it may even be a suitable substitute for the NASA-TLX.     

气调储藏—O_2和CO_2对种子生理活性影响的研究

本文研究了气调储藏中o_2和co_2对种子生活活性的影响.结果表明在气调储藏中,种子活力与乙醇含量呈负相关,乙醇在种子中的积累是造成种子活力下降的重要原因之一.乙醇在种子中的积累又受制于种子水分和氧浓度的影响,水分与气体对种子活力的关系是FH_20>FO_2>FCO_2,因此,要求种子水分在采用气调储藏时应低于16%.本文还提出一个新的种子活力指标—V/A值.它能有效地反映种子生理活性状态和乙醇积累对种子品质的损伤.     

Detection Probability Estimation of Directional Antennas and Omni-Directional Antennas

This paper studies the problem of detection of directional antennas and omni-directional antennas by hostile detection systems. We present a model for calculating the probability of detecting a transmitter at arbitrary location around the transmitter. Our study shows that, if a directional antenna employs the same transmit power as an omni-directional antenna, the directional antenna can not decrease the probability of being detected. In some scenarios, a directional antenna is more likely to be detected than an omni-directional antenna. However, if a directional antenna provides the same Effective Isotropic Radiated Power in the direction of the receiver as an omni-directional antenna, the transmit power needed by a directional antenna to send data is much less than that of an omni-directional antenna. In this scenario, the probability of detecting a directional antenna is reduced by over 90%. This reveals that directional antennas can be used to build a secure path to send data at low probability of being detected by adversaries.     

Environment-adjusted regional energy efficiency in Taiwan

This study applies the four-stage DEA procedure to calculate the energy efficiency of 23 regions in Taiwan from 1998 to 2007. After controlling for the effects of external environments, only Taipei City, Chiayi City, and Kaohsiung City are energy efficient. Note that Kaohsiung City reaches the efficiency frontier due to the adjustment via partial environmental factors such as higher education attainment and transport vehicles. We also find a worsening trend for Taiwan’s energy efficiency. Not only is there a gap of energy efficiency between Taiwan’s metropolitan areas and the other regions, but the gap has also widened in recent years. Those inefficient counties should be given priority and the savings potential. Except for road density, the evidence indicates that each environmental factor has partial incremental effects on input slacks. As more cars and motorcycles are unfavorable externalities affecting partial energy efficiency, the central government should help local governments retire inefficient old motor vehicles, encourage energy-saving vehicle models, and provide convenient mass transportation systems. Besides, people with higher education cause industrial energy inefficient in Taiwan. The conscious of effective energy saving is necessary to schools, communities, and employee accordingly.     

Effect of Particle Structure on Quality Retention of Bio-Products During Thermal Drying

To study the influence of particle structure on quality retention of hioproducts during thermal drying, the porous particles formed of albumin and solid carriers were dried in a vibm-fluidized bed dryn at different inlet air temperatures and different initial bulk porosities. Equations to predict temperature and moishrre content of panicles as well as the kinetics of biomass degradation were developed. The particle bulk porosity was incorporated into concentration-dependent moisture diffusivity model to estimate the erect of particle structure on product quality. The analysis of both calculated and experimental results indicates that the more porous structure promotes moisture diffusion, increases drying rate and finally improves the quality retention of bio-products. An extensive literature survey on quality retention issues during thermal drylng has been done.     

Targeted Delivery of Anesthetic Agents to Bone Tissues using Conductive Microneedles Enhanced Iontophoresis for Painless Dental Anesthesia

Pain management during dental procedures is a cornerstone for successful daily practice. In current practice, the traditional needle and syringe injection is used to administer local anesthesia. However, the appearance of long needles and the pain associated with it often leads to dental anxiety deterring timely interventions. Microneedles (MNs) have emerged as a minimally invasive alternative to hypodermic needles and shown to be effective in transdermal drug delivery applications. In this article, the potential use of MNs for local anesthesia delivery in dentistry is explored. The development of a novel conductive MN array that can be used in combination with iontophoresis technique to achieve drug penetration through the oral mucosa and the underlying bone tissue is presented. The conductive MN array plays a dual-role, creating micro-conduits and lowering the resistance of the oral mucosa. The reduced tissue resistance further enhances the application of a low-voltage current that is able to direct and accelerate the drug molecules to target the sensory nerves supplying teeth. The successful delivery of lidocaine using this new strategy in a clinically relevant rabbit incisor model is shown to be as effective as the current gold standard.     

Preview predictive control layer design based upon known wind turbine blade‐pitch controllers

The use of upstream wind measurements has motivated the development of blade‐pitch preview controllers for improving rotor speed tracking and structural load reduction beyond that achievable via conventional feedback control. Such preview controllers, typically based upon model predictive control (MPC) for its constraint handling properties, alter the closed‐loop dynamics of the existing blade‐pitch feedback control system. This can result in a deterioration of the robustness properties and performance of the existing feedback control system. Furthermore, performance gains from utilising the upcoming real‐time measurements cannot be easily distinguished from the feedback control, making it difficult to formulate a clear business case for the use of preview control. Therefore, the aim of this work is to formulate a modular MPC layer on top of a given output‐feedback blade‐pitch controller, with a view to retaining the closed‐loop robustness and frequency‐domain performance of the latter. The separate nature of the proposed controller structure enables clear and transparent quantification of the benefits gained by using preview control, beyond that of the underlying feedback controller. This is illustrated by results obtained from high‐fidelity closed‐loop turbine simulations, showing the proposed control scheme incorporating knowledge of the oncoming wind and constraints achieved significant 43% and 30% reductions in the rotor speed and flap‐wise blade moment standard deviations, respectively. Additionally, the chance of constraint violations on the rotor speed decreased remarkably from 2.15% to 0.01%, compared to the nominal controller. Copyright © 2017 John Wiley & Sons, Ltd.     

Repetitive acceptance sampling plans for burr type XII percentiles

Under truncated life tests, two types of repetitive acceptance sampling plans are proposed to ensure the quality of products in terms of percentile lifetime when the lifetime follows the Burr type XII distribution. The proposed acceptance sampling plans, including the ordinary repetitive acceptance sampling plan and the repetitive version of a group acceptance sampling plan, are developed to meet producer’s and consumer’s risks at two specified lifetime percentiles, simultaneously. Useful tables have been established for a wide range of Burr type XII distributions which include the log–logistic distribution for practical utilization. Finally, some examples are provided for illustration.     

In vitro impairment of interleukin-5 production in HLA-B8, DR3-positive individuals implications for immunoglobulin A synthesis dysfunction

Healthy subjects carrying the HLA-B8,DR3 haplotype may show a large number of immune dysfunctions. Concerning T-cell dysfunctions, the most intriguing is a defect of the early phases of T-cell activation, responsible for the impairment of in vitro mitogen-stimulated cytokine production. Regarding B-cell dysfunctions, one the most fascinating topics is the association between this haplotype and IgA deficiency in healthy blood donors. Accordingly, HLA-B8,DR3-positive healthy subjects show significantly lower values of serum IgA than HLA-B8,DR3-negative ones. Because IL-5 is a stimulating factor for the secretion of IgA by committed B cells, we have analyzed the in vitro mitogen-stimulated IL-5 production by MNCs from healthy HLA-B8,DR3-positive individuals to study whether they display an impaired production of IL-5. The results clearly demonstrate that MNCs from HLA-B8,DR3-positive individuals display significant reduction of IL-5 production, suggesting that IgA synthesis dysregulation observed in HLA-B8,DR3-positive subjects could be due to an impairment of IL-5 production.     

Effect of Carrier Matrix on Fermentative Production of Ethanol by Surface Immobilised Yeast Cells

The production of ethanol for potable preparations is well established and the traditional methods used therein are changing. More important, however, has been the advent of fuel alcohol, first in Brazil, but now with ever-increasing possibilities of being adopted in North America and Europe. Production of alcohol by fermentation has therefore come to stay, and it is essential to discover ways of improving the productivities of such fermentations. The effect of organic (cellulose and corn stover) and inorganic matrices (silica gel, porous silica, Celite and derivatised Celite) on the performance of ethanol fermentation by Saccharomyces bayanus was tested. The hydrophilicity degree of the support seems to play an important role in the ability of reaching high ethanol concentrations in the fermentation of 300 g dm^?3 of glucose. Cells immobilised on carriers with low hydrophilicity degree, namely Celite, lead to better results (residual glucose: 56 g dm^?3; ethanol: 111 g dm^?3) than their free counterparts (residual glucose: 136 g dm^?3; ethanol: 71 g dm^?3). Celite was selected for further cell immobilisation studies, including time of adsorption, whole cell concentration, initial glucose concentration and time of addition of the support to the fermentation medium. The latter has revealed to be a very important factor, improving the performance of ethanol fermentation by reducing the fermentation time. Previous immobilisation seems to have no effect when compared with the simple addition of Celite to the inoculated medium and the eficiency of Celite did not increase when the concentration of glucose was enhanced.