Table Height Research Articles

The ergonomics of women in surgery

Among surgeons who regularly perform minimally invasive surgery, as many as 87 % report injuries or symptoms related to job performance. Operating room and instrument design have traditionally favored surgeons who are taller and who possess hands that are, in general, large and strong. We hypothesize that women may be experiencing more ergonomic difficulties than men for whom the operating room and surgical instruments, although uniformly perilous, more traditionally have accommodated. A 23-item web-based survey was offered via email to 2,000 laparoscopic surgeons and fellows currently practicing. The survey addressed four categories: demographics, physical symptoms, ergonomics, and environment/equipment. Key questions allowed us to identify which body part experienced which symptoms. There was a 15.7 % overall response rate. Among respondents, 17 % (54/314) were female. Women were significantly younger, shorter, had smaller glove size, and fewer years in practice than men surveyed (all p values < 0.0001). Of women reporting, 86.5 %—comparable to men—attribute physical discomfort to laparoscopic operating. Female surgeons are more likely to receive treatment for their hands, which includes the wrist, thumb, and fingers (odds ratio 3.5, p = 0.028). When men and women of the same glove size were compared, women with a larger glove size (7–8.5) reported more cases of treatment for their hands than men of the same glove size. (21 vs. 3 %, p = 0.016). Women who wore a size 5.5–6.5 surgical glove reported significantly more cases of discomfort in their shoulder area (neck, shoulder, upper back) than men who wore the same size surgical glove (77 vs. 27 %, p = 0.004). Women surgeons are experiencing more discomfort and treatment in their hands than male surgeons. Redesign of laparoscopic instrument handles and improvements to table height comprise the most promising solutions to these ergonomic challenges.

Prediction of the Groundwater Rebound Process in a Backfilled Open Cut Mine Using an Artificial Neural Network

A neural network model was used to predict the groundwater rebound process after cessation of dewatering at a restored open cut coal site in the East Midlands area of the UK. Time (days after dewatering), water table levels in the aquifer and the backfilled site, hydraulic conductivity of the aquifer and backfilled site, and precipitation were used as input. The output of the network was the water table height, until the water table reached its equilibrium position. A feed-forward artificial neural network that uses batch gradient descent with a momentum-learning algorithm and 6-1-6-1 arrangement was found capable of predicting the groundwater rebound process. Predicted values were very close to the monitored results. The correlation coefficient values were 0.98221 for the training set, and 0.99329, 0.99499, 0.98667, 0.98289, and 0.97141 during the testing stage for the five monitoring points, showing that the model prediction was satisfactory.

Factors affecting the measurement of the vertical hydraulic conductivity of a streambed sediment using standpipe tests

AbstractThe vertical hydraulic conductivity (Kv) of a stream or lake sediment is often determined in the field using standpipe tests. Calculation of Kv is based on the assumption that the hydraulic head in the pipe is equal to that of the stream or lake stage. In this work, a modified equation for Kv is developed for the standpipe test which is applicable when this assumption is not valid. The equation involves not only the hydraulic head at different times but also the difference in the hydraulic head (a) between the groundwater level and river stage. The effects of certain factors on Kv, such as the ratio of the hydraulic head at different times (h1/h2), the difference a, and the initial water table height (h0), are also discussed. The results show that when h1/h2 is constant, the relative error (Er) in Kv increases with the ratio a/h2. Furthermore, if a/h2 &lt; 0.05, then for any value of h1/h2, Er is less than 5% using the modified equation. Also, if a/h2 is large, hydraulic head readings with larger h1/h2 ratios must be used to avoid large Er values. The results of a field test also indicate that the error in Kv decreases as the value of h0 increases. Copyright © 2013 John Wiley &amp; Sons, Ltd.

고령자의 전동침대 사용 시 테이블 높이에 따른 상지와 체간의 근활성도 분석

PURPOSE: In recent years, senior friendly device is growing rapidly because of population aging The study was designed to investigate the effects of table height of electronic bed on upper extremity and trunk EMG in elderly. METHODS: Thirty right-handed elderly without history of neurological and musculoskeletal dysfunction were participated in this study. Three heights of the table (3/3 height, 2/3 height, and 1/3 height between top of the shoulder and olecranon) were provided. During the eating performance, surface electromyography (EMG) was used to measure muscle activity, and electrodes were attached to the deltoid middle fiber, serratus anterior, suprapinatus, upper trapezius, rhomboideus, cervical part of longissimus, thoracic part of longissimus, lumbar part of longissimus on right. One way ANOVA was conducted for the statistical analysis. RESULTS: There were significant differences in deltoid middle fiber, suprapinatus, upper trapezius, rhomboideus, lumbar part of longissimus in the 3 different height of table (p<.05). The deltoid middle fiber, suprapinatus, upper trapezius, and lumbar part of longissimus were significantly increased in higher table than lower table(p<.05). And the rhomboideus was significantly decreased in higher table than lower table(p<.05). CONCLUSION: This study demonstrates that different height of table affect upper extremity and trunk muscle activity. The table height of olecranon is the best for elderly.

물리치료사의 초음파 작업시 테이블 높이에 따른 척추기립근의 근전도 활동 분석

The higher table heights was, the lower %RVC of the T10, T12, L2, L4 erect spinae at both sides. The left and right T10, T12 and the left L4 showed significant differences. The lower the spinal level was, the higher %RVC of both erect spinae at 45cm, 56.2cm, 67.5cm. The left erect spinae at 56.2cm, right erect spinae at 45cm, 67.5cm showed significant differences.

Transporte ascendente da mistura formulada de imazethapyr e imazapic em resposta à profundidade do lençol freático

Os herbicidas usados na cultura do arroz Clearfield® podem persistir no ambiente e causar danos no arroz não tolerante, cultivado em sucessão. Esse dano pode ser de intensidade variável, dependendo, dentre outros fatores, do movimento ascendente do herbicida para região de absorção do sistema radicular das plantas. O objetivo desta pesquisa foi verificar o efeito da altura do lençol freático no movimento ascendente do herbicida composto pela mistura formulada de imazethapyr e imazapic. Para isso, foram coletados lisímetros de solo com auxílio de tubos de PVC (15x30cm). O herbicida foi aplicado na superfície inferior dos lisímetros, onde foram simulados diferentes profundidades do lençol freático (0, 5, 10, 15 e 25cm da superfície do solo). Os lisímetros permaneceram nessa condição por período de 150 dias, quando foram cortados longitudinalmente, seccionados em porções de 5cm (0-5 a 25-30cm) e realizado bioensaio com a cultivar de arroz não tolerante, IRGA 417. Com os resultados obtidos, foi possível concluir que ocorre movimento ascendente da mistura formulada dos herbicidas imazethapyr e imazapic ao longo do perfil do solo de várzea durante o período da entressafra do arroz irrigado, sendo este maior quando o lençol freático está localizado mais próximo da superfície do solo. O movimento ascendente através da diluição do herbicida na solução do solo ocorre por fluxo de massa através do arraste pela água, transportada por capilaridade para zonas mais superficiais do solo.

Alternate wetting and drying irrigation for rice in Bangladesh: Is it sustainable and has plant breeding something to offer?

AbstractThe crop management practice of alternate wetting and drying (AWD) is being promoted by IRRI and the national research and extension program in Bangladesh and other parts of the world as a water‐saving irrigation practice that reduces the environmental impact of dry season rice production through decreased water usage, and potentially increases yield. Evidence is growing that AWD will dramatically reduce the concentration of arsenic in harvested rice grains conferring a third major advantage over permanently flooded dry season rice production. AWD may also increase the concentration of essential dietary micronutrients in the grain. However, three crucial aspects of AWD irrigation require further investigation. First, why is yield generally altered in AWD? Second, is AWD sustainable economically (viability of farmers' livelihoods) and environmentally (aquifer water table heights) over long‐term use? Third, are current cultivars optimized for this irrigation system? This paper describes a multidisciplinary research project that could be conceived which would answer these questions by combining advanced soil biogeochemistry with crop physiology, genomics, and systems biology. The description attempts to show how the breakthroughs in next generation sequencing could be exploited to better utilize local collections of germplasm and identify the molecular mechanisms underlying biological adaptation to the environment within the context of soil chemistry and plant physiology.

Ergonomically adjustable school furniture for male students

The need for adjustability in school furniture, in order to accommodate the variation in anthropometric measures of different genders, cultures and ages is becoming increasingly important. Four chair-table combinations, different in dimensions, with adjustable chair seating heights and table heights were designed, manufactured and distributed to schools in Riyadh city. The number of the student participants was 28 (6 to <9 years), 30 (9 to <12 years), 30 (12 to <15 years) and 30 (≥ 15 years) in first, second, third and fourth age-group sets respectively. Muscular activity signals (EMGs) for both neck dorsal muscles and upper trapezius muscles, posture measures in terms of neck angle, viewing angle, back angle and discomfort ratings were considered as dependent factors. New designed adjustable sets versus current sets available in the schools were the independent variables. The results indicated that EMGs signals for both neck dorsal and upper trapezius muscles in the new sets were significantly lower when compared to the current sets. The three posture measures associated with the new sets were significantly improved when compared to the current sets. Finally, the participants' ratings of discomfort were significantly low for sitting on the new sets compared to sitting on the current sets. Key words: School furniture, adjustable seat, EMG, discomfort rating, anthropometry

MUSCULOSKELETAL SYMPTOMS AMONGST ENDOSCOPISTS

IntroductionGastroenterologists may be at risk of overuse / repetitive strain type injuries. The number, complexity and duration of endoscopic procedures, in addition to the career duration are possible contributing factors....

Impacts from ditching salt marshes in the mid-Atlantic and northeastern United States

Tidal inundation extent and duration, and water drainage and retention by marsh peat — marsh hydrology — determine most physical and ecological characteristics of salt marsh systems. Ditching, installed across nearly all marshes on the US east coast by 1940 to control mosquitoes, alters marsh hydrology. Two linchpin papers are used here as springboards to review the literature that describes the resulting effects, which clearly include reduced water table height for most marshes and changes in avian populations. Effects on invertebrate populations, including mosquitoes, are generally less, although to a smaller degree than is sometimes reported. Impacts on nekton are not clear, although probably negative. Tidal range and the degree of tide asymmetry appear to have greater effects on intermarsh variations in effects from ditching than has generally been appreciated or studied. Overall, although changed patterns of nutrient releases and promotion of Phragmites australis invasions are important ecological effects extending beyond individual sites, and salt marsh aesthetics are marred, ditching impacts are less than certain other anthropogenic alterations of coastal processes that affect salt marshes and estuarine ecology to a much greater extent.

SU‐E‐T‐628: Impact of Large SSD On the Plan Quality of Energy‐Intensity Modulated Electron Therapy

Purpose: In photon MLC (pMLC) delivered energy‐intensity modulated electron therapy, a short SSD was preferred for reducing beam penumbra caused by electron in‐air scatter. However, due to some restrictions (e.g. table height limit on some accelerators), a large SSD may be an only choice. This work presents our preliminary results of the impact of a large SSD on an ultimate MERT plan. Methods: A house‐grown Monte Carlo (MC)‐based optimization/dose calculation code was used to generate plans for the Artiste linac with a breast phantom, at 60 cm and 90 cm SSD, respectively. The plans employed four different electron energies (6, 9, 12, 15 MeV) and was normalized to ensure 85% of the CTV to receive 100% of the prescription dose. Their DVHs are then evaluated for target (breast), left lung and heart. Results: When a 90 cm SSD was used instead of a 60 cm SSD, the maximum dose of the CTV increased by 5% while the minimum dose decreased by 3.6%. The left lung showed a 10% increase in the maximum dose while D10% (dose to 10% of volume) and D30% of the lung increased by a factor of 1.39 and 2.23, respectively. The maximum dose to the heart increased by 20% and its D10% and D30% were about 1.5 times larger. Conclusion: With a larger SSD (e.g., 90 cm as compared to 60 cm), increased air‐scattered electrons may lead to substantial deterioration of the overall plan quality ‐ increased target dose heterogeneity and higher doses to critical structures. However, absolute doses received by these critical structures may be still low and further investigations are warranted to find out as to whether MERT with a large SSD is still a better treatment as compared with conventional treatments for some disease sites.

Effects of Change in the Height of Therapy Tables on the Fatigue of Splenius Capitis Muscle and Trapezius Muscle

The purpose of this study is to analysis of muscle fatigue in the upper trapezius and splenius capitis muscles according to therapy table height variation. The subjects were consisted of 15 healthy adults(10 males, 5 females) who had no medical history of neurological and musculoskeletal problems. In experiment, wireless electrode EMG system was measured for each the upper trapezius and splenius capitis muscles during the treatment performed on table. the differences in the muscle fatigue was compared for 4 types of table height(-6cm, -3cm, 0, +3cm from elbow in <TEX>$90^{\circ}$</TEX> flexion position). Muscle fatigue according to therapy table height were significant difference except for left upper trapezius. And muscle fatigue of right upper trapezius and splenius capitis showed significant decrease in +3cm table height compared to -6cm table height(p<.05). Muscle fatigue of right upper trapezius and splenius capitis were the highest in -6cm table height, but those were the lowest in +3cm table height. This study propose to change therapy table height higher than +3cm from elbow in <TEX>$90^{\circ}$</TEX> flexion position, if you hope to reduce muscle fatigue.

Surgeon education decreases radiation dose in complex endovascular procedures and improves patient safety

Complex endovascular procedures such as fenestrated endovascular aneurysm repair (FEVAR) are associated with higher radiation doses compared with other fluoroscopically guided interventions (FGIs). The purpose of this study was to determine whether surgeon education on radiation dose control can lead to lower reference air kerma (RAK) and peak skin dose (PSD) levels in high-dose procedures. Radiation dose and operating factors were recorded for FGI performed in a hybrid room over a 16-month period. Cases exceeding 6 Gy RAK were investigated according to institutional policy. Information obtained from these investigations led to surgeon education focused on reducing patient dose. Points addressed included increasing table height, utilizing collimation and angulation, decreasing magnification modes, and maintaining minimal patient-to-detector distance. Procedural RAK doses and operating factors were compared 8 months pre- (group A) and 8 months post- (group B) educational intervention using analysis of variance with Tukey pairwise comparisons and t-tests. PSD distributions were calculated using custom software employing input data from fluoroscopic machine logs. Of 447 procedures performed, 300 FGIs had sufficient data to be included in the analysis (54% lower extremity, 11% thoracic endovascular aneurysm repair, 10% cerebral, 8% FEVAR, 7% endovascular aneurysm repair, 5% visceral, and 5% embolization). Twenty-one cases were investigated for exceeding 6 Gy RAK. FEVAR comprised 70% of the investigated cases and had a significantly higher median RAK dose compared with all other FGIs (P < .0001). There was no difference in body mass index between groups A and B; however, increasing body mass index was an indicator for increased RAK. PSD calculations were performed for the 122 procedures that focused on the thorax and abdomen (group A, 80 patients; group B, 42 patients). Surgeon education most strongly affected table height, with an average table height elevation of 10 cm per case after education (P < .0001). The dose index (PSD/RAK ratio) was used to track changes in operating practices, and it decreased from 1.14 to 0.79 after education (P < .0001). These changes resulted in an estimated 16% reduction in PSD. There was a trend toward a decrease in patient to detector distance, and the use of collimation increased from 25% to 40% (P < .001) for all cases; however, these did not result in a decrease in PSD. The number of cases that exceeded 6 Gy RAK did not change after education; however, the proportion of non-FEVAR cases that exceeded 6 Gy decreased from 40% to 20%. Surgeon education on the appropriate use of technical factors during FGIs improved operating practice, reduced patient radiation dose, and decreased the number of non-FEVAR cases that exceeded 6 Gy. It is essential that vascular surgeons be educated in best operating practices to lower PSD; nonetheless, FEVAR remains a high-dose procedure.

HTML Automatic Table Layout

Automatic layout of tables is required in online applications because of the need to tailor the layout to the viewport width, choice of font, and dynamic content. However, if the table contains text, minimizing the height of the table for a fixed maximum width is NP-hard. Thus, more efficient heuristic algorithms are required. We evaluate the HTML table layout recommendation and find that while it generally produces quite compact layout it is brittle and can lead to quite uncompact layout. We present an alternate heuristic algorithm. It uses a greedy strategy that starts from the widest reasonable layout and repeatedly chooses to narrow the column for which narrowing leads to the least increase in table height. The algorithm is simple, fast enough to be used in online applications, and gives significantly more compact layout than is obtained with HTML’s recommended table layout algorithm.

Comparison of soil greenhouse gas fluxes from extensive and intensive grazing in a temperate maritime climate

Abstract. Greenhouse gas (GHG) fluxes from a seminatural, extensively sheep-grazed drained moorland and intensively sheep-grazed fertilised grassland in South East (SE) Scotland were compared over 4 yr (2007–2010). Nitrous oxide (N2O) and methane (CH4) fluxes were measured by static chambers, respiration from soil plus ground vegetation by a flow-through chamber, and the net ecosystem exchange (NEE) of carbon dioxide (CO2) by eddy-covariance. All GHG fluxes displayed high temporal and interannual variability. Temperature, radiation, water table height and precipitation could explain a significant percentage of seasonal and interannual variations. Greenhouse gas fluxes were dominated by the net ecosystem exchange of CO2 at both sites. Net ecosystem exchange of CO2 and respiration was much larger on the productive fertilised grassland (−1567 and 7157 g CO2eq m−2 yr−1, respectively) than on the seminatural moorland (−267 and 2554 g CO2eq m−2 yr−1, respectively). Large ruminant CH4 (147 g CO2eq m−2 yr−1) and soil N2O (384 g CO2eq m−2 yr−1) losses from the grazed grassland counteracted the CO2 uptake by 34%, whereas the small N2O (0.8 g CO2eq m−2 yr−1) and CH4 (7 g CO2eq m−2 yr−1) emissions from the moorland only impacted the NEE flux by 3%. The 4-yr average GHG budget for the grazed grassland was −1034 g CO2eq m−2 yr−1 and −260 g CO2eq m−2 yr−1 for the moorland.

Climate-induced landslide reactivation at the edge of the Most Basin (Czech Republic) – progress towards better landslide prediction

Abstract. The catastrophic landslide at Eisenberg in North Bohemia was reactivated during January 2011. This study integrates a range of geoscientific evidence in order to constrain the spatial and temporal development of this reactivation. It has investigated long-term geodetic measurements to assess the morphological development of the site over the last two decades. There is evidence to suggest that, over this period, the site had been subjected to progressive deformation caused by the collapse of an old mine gallery. However, climatic data show that the reactivation itself was triggered by a dramatic rise in the water table induced by rapid snowmelt during a period of winter warming. Furthermore, geomorphological mapping has been used to characterise the morphology of the reactivated landslide and geophysical profiling has been used to analyse its internal structure. The results show that fissures are continuing to develop above the reactivated landslide scarp while highly saturated stiff-fissured claystones provide an incipient slide plane. The application of laser scanning has shown minimal evidence for ongoing landslide activity. It is, however, clear that future landslide events will occur here due to the favourable lithological, structural, and geotechnical conditions. Finally, we propose that future landslide activity at the site may be predicted by the height of water table as this defines theoretical pore pressure at the depth of the shear plane.

치과기공사의 체형에 적합한 작업대의 분석

본 연구는 치과기공사의 체형에 적합한 인간공학적인 작업 자세를 위한 작업대의 높이를 연구하고 개선방안을 제시하는 것이 목적이다. 이를 위해 경기지역과 충청도에 소재한 대학의 치기공과 3학년 학생 77명을 대상으로 학생의 신장과 몸무게 및 신체치수를 측정하였고 임상실습 시 가장 힘들었던 작업 자세에 대해 조사하였다. 또한 이를 실제작업환경과 비교 분석을 위해 수도권에 위치한 종합병원 치과기공실 2곳과 치과기공소 15곳을 직접 방문하여 의자를 포함한 책상 및 작업대 높이를 측정하여 측정값을 통계학적으로 분석 하였다. 특히 가장 많은 불편을 초래하는 원인 인자에 대해 세부적인 분석을 하였으며 이러한 분석 자료를 검토한 결과 다음과 같은 결론을 얻었다. 임상실습 시 가장 불편을 느끼는 작업대는 샌드작업대의 높이로 조사되었고 3학년 학생들의 성별과 불편한 작업대의 선택 항목간과 상관관계는 없는 것으로 분석되었다. 또한 샌드작업대가 불편했던 원인은 권장수치보다 낮은 샌드작업대의 높이 때문인 것으로 추정하였으며, 3학년 학생에게 적합한 샌드작업대의 최적의 높이는 권장치보다 다소 높은 것으로 분석되었다. 샌드작업대의 최적의 높이는 치기공과 3학년 학생의 키에 따라 다소 편차가 있었으며 개수대의 높이는 권장안보다 낮은 것으로 분석되었다. 또한 일반적으로 제시되는 권장안은 기본적으로 모든 작업자의 상이한 신장에 균일하게 적용되지 않음을 알 수 있었다. The purpose of this study was to evaluate the height of workbench in dental lab for ergonomic body type which dental technicians are suitable and suggest to effective improvement of workspace. For this purpose, we measured the height, weight, body sizes of total 77 junior majoring in dental laboratory science where they study school located in Gyeonggi and Chungcheong area and we research uncomfortable body type when they had a clinical training. For comparative analysis we had visited 15 dental lab and 2 dental lab of general hospital and we had measured the height of workbench and desk including chair and then We had statistical analysis measured value. Especially we analyzed the important factor causing inconvenience for work environment. As a result, we had examined, we found following results The sand table was the most uncomfortable equipment, when they have clinical training. There is no correlation between sexual characteristics of junior in college and selection of uncomfortable equipment. It is reasonable to assume that sand table which is lower than recommended height brings out inconvenience. It is analyzed that the optimum height of sand table in dental lab for junior in college is lower than the recommended height. The optimum height of sand table in dental lab has deviation according to height of junior in college. The height of worktable in dental lab was lower than recommended height. The recommended range could not apply to posture of dental technician with different height uniformly.

Real-time catheter tracking for high-dose-rate prostate brachytherapy using an electromagnetic 3D-guidance device: A preliminary performance study

In order to increase the accuracy and speed of catheter reconstruction in a high-dose-rate (HDR) prostate implant procedure, an automatic tracking system has been developed using an electromagnetic (EM) device (trakSTAR, Ascension Technology, VT). The performance of the system, including the accuracy and noise level with various tracking parameters and conditions, were investigated. A direct current (dc) EM transmitter (midrange model) and a sensor with diameter of 1.3 mm (Model 130) were used in the trakSTAR system for tracking catheter position during HDR prostate brachytherapy. Localization accuracy was assessed under both static and dynamic analyses conditions. For the static analysis, a calibration phantom was used to investigate error dependency on operating room (OR) table height (bottom vs midposition vs top), sensor position (distal tip of catheter vs connector end of catheter), direction [left-right (LR) vs anterior-posterior (AP) vs superior-inferior (SI)], sampling frequency (40 vs 80 vs 120 Hz), and interference from OR equipment (present vs absent). The mean and standard deviation of the localization offset in each direction and the corresponding error vectors were calculated. For dynamic analysis, the paths of five straight catheters were tracked to study the effects of directions, sampling frequency, and interference of EM field. Statistical analysis was conducted to compare the results in different configurations. When interference was present in the static analysis, the error vectors were significantly higher at the top table position (3.3 ± 1.3 vs 1.8 ± 0.9 mm at bottom and 1.7 ± 1.0 mm at middle, p < 0.001), at catheter end position (3.1 ± 1.1 vs 1.4 ± 0.7 mm at the tip position, p < 0.001), and at 40 Hz sampling frequency (2.6 ± 1.1 vs 2.4 ± 1.5 mm at 80 Hz and 1.8 ± 1.1 at 160 Hz, p < 0.001). So did the mean offset errors in the LR direction (-1.7 ± 1.4 vs 0.4 ± 0.5 mm in AP and 0.8 ± 0.8 mm in SI directions, p < 0.001). The error vectors were significantly higher with surrounding interference (2.2 ± 1.3 mm) vs without interference (1.0 ± 0.7 mm, p < 0.001). An accuracy of 1.6 ± 0.2 mm can be reached when using optimum configuration (160 Hz at middle table position). When interference was present in the dynamic tracking, the mean tracking errors in LR direction (1.4 ± 0.5 mm) was significantly higher than that in AP direction (0.3 ± 0.2 mm, p < 0.001). So did the mean vector errors at 40 Hz (2.1 ± 0.2 mm vs 1.3 ± 0.2 mm at 80 Hz and 0.9 ± 0.2 mm at 160 Hz, p < 0.05). However, when interference was absent, they were comparable in the both directions and at all sampling frequencies. An accuracy of 0.9 ± 0.2 mm was obtained for the dynamic tracking when using optimum configuration. The performance of an EM tracking system depends highly on the system configuration and surrounding environment. The accuracy of EM tracking for catheter reconstruction in a prostate HDR brachytherapy procedure can be improved by reducing interference from surrounding equipment, decreasing distance from transmitter to tracking area, and choosing appropriated sampling frequency. A calibration scheme is needed to further reduce the tracking error when the interference is high.

Does temperature or runoff control the feedback between chemical denudation and climate? Insights from NE Iceland

The relative role of temperature and runoff on the chemical denudation rates in seven NE Iceland river catchments were determined through the analysis of river water chemistry collected over a five-year period. Denudation rates are quantified from the instantaneous riverine Na fluxes. As sodium is the major element least incorporated into secondary phases, its denudation rate is directly related to the dissolution rate of the catchments’ primary rocks. Chemical transport in rivers is taken to be analogous to laboratory mixed-flow reactors; dissolution rates in mixed flow-reactors at fixed temperature and flow rate are a function of fluid composition, degree of fluid undersaturation, the Arrhenius activation energy, and reactive surface area. Data analysis suggests that the Na chemical denudation rates of the NE Icelandic catchment rocks increase by 13% for each °C increase in temperature. Of this 13%, 5% stems from the Arrhenius activation energy and 8% stems from the temperature dependence of the fluid pH and aqueous Al activity. Increased runoff raises the height of the water table thus enhancing chemical denudation by increasing the reactive surface area of weathering minerals. Regression of measured Na fluxes indicate that the average active water–rock surface area of the studied catchments increase linearly with runoff such that a 1% rise in runoff produces a 1% increase in reactive surface area and chemical denudation rates. The relative role of temperature versus runoff on chemical denudation depends, therefore, on the relative changes in these two rate controlling parameters. The maximum temperature variation of the studied rivers was 15.4°C, which would increase Na chemical denudation rates by a factor of 6. In contrast, instantaneous runoff varies by as much as a factor of 250. These observations suggest that runoff dominates the instantaneous variation of the Na chemical denudation rates of the studied catchments.

Analysis of Muscle Fatigue of Erect Spinae Caused by Treatment Table Height in Ultrasound Therapy

[Purpose] The objective of this study was to propose a work environment that could reduce musculoskeletal workload. Accordingly, spinal muscle fatigue caused by ultrasound therapy at various treatment table heights was examined and compared. [Subjects and Methods] Twenty-five healthy subjects participated in this experiment. The table height was set to 100%, 125%, and 150% of the stool height (45 cm). The electromyographic signals of the erector spinae at the thoracic (T10, T12) and lumbar (L2, L4) levels were collected by an electromyography (EMG) system during the performance of ultrasound therapy. The median frequencies were then calculated and compared. [Results] The lower the table height was, the smaller the median frequencies of thoracic and lumbar erector spinae on both sides were. The T10 and T12 levels on both sides and the left L2 region showed significant differences among the table heights. At every spinal level, the median frequency of the left erector spinae was lower than that of the right: T10, T12, L2, and L4 at 100%, L4 at 125%, and T10, T12, L2, and L4 at 150% showed significant differences. [Conclusion] During ultrasound therapy muscle fatigue increased at higher table heights and the muscle fatigue of the left erector spinae was greater than that of the right side. To reduce muscle fatigue, we recommend the table height work is raised to an appropriate height, and that is shared between left and right arms.