Difference In Coefficient Of Variation Research Articles

Examination of Left-Right Differences and Intertrial Variability in Grand Jeté Among Professional Ballet Dancers.

Introduction: Ballet demands diverse physical prowess, requiring dancers to execute movements symmetrically, irrespective of their dominant leg. Ballet often includes jumps, including the basic open-leg leap-the grand jeté-which requires uniform performance regardless of the leg on which the leap is initiated. However, no studies have simultaneously evaluated the effects of dominant leg or movement variation on jump height, leg split angle, jump time, and floor reaction forces during take-off and landing, which are related to the feeling of floating in the grand jeté. This study aimed to determine whether the high-level, stable, and beautiful performance required of professional ballet dancers in the grand jeté is affected by the dominant leg. Methods: Twelve female ballet dancers, all right leg dominant, performed the grand jeté 3 times on each side, distinguishing between dominant (right leg landing) and non-dominant (left leg landing) grand jetés. Utilising 3D movement analysis, we measured jump height, jump time, maximum leg split angle, and maximum vertical ground reaction force (VGRF) during take-off and landing. Mean values and coefficients of variation were calculated for each analysed parameter. Paired sample t-tests were conducted to assess differences between left and right grand jetés, with a significance level set at P < .05. Results: Statistically significant differences were observed in jump height (P = .028) and jump time (P = .001) when comparing the average of three trials for each side. However, no significant differences were found in maximum leg split angle (P = 0.643), maximum VGRF at take-off (P = .200), and maximum VGRF at landing (P = .109). In addition, no significant differences in coefficients of variation were identified for all items. Conclusion: Ballet dancers showed consistent performance on dominant and non-dominant legs but higher and longer jumps for grand jetés landing on the dominant leg, which may have affected overall performance.

Effect of femtosecond laser-assisted phacoemulsification on corneal endothelium and prognosis of diabetic patients with cataract with different nuclear hardness

Objective: To assess the impact of femtosecond laser-assisted phacoemulsification on corneal endothelial characteristics and prognosis among patients with type 2 diabetes and age-related cataracts, considering varying nuclear hardness. Methods: This non-randomized controlled trial involved 161 patients (161 eyes) with type 2 diabetes undergoing cataract extraction at Weifang Eye Hospital between March 2020 and December 2022. The cohort comprised 73 males and 88 females, with an average age of (65.9±5.23) years. Based on patient preference, 101 individuals underwent conventional phacoemulsification (group A), while 60 chose femtosecond laser-assisted phacoemulsification (group B). Patients were further stratified based on Emery-Little grade of lens nuclei into A1/B1 (grade Ⅰ and Ⅱ), A2/B2 (grade Ⅲ), and A3/B3 (grade Ⅳ) subgroups. The study compared effective phacoemulsification time (EPT), cumulative energy release of phacoemulsification (CDE), central corneal thickness (CCT), endothelial cell density (ECD), coefficient of variation (CV), and hexagon cell ratio (HEX) before and after surgery at 1 day, 1 week, 1 month, and 3 months. Results: The intraoperative EPT of patients in groups A and B were (6.52±4.93) and (5.63±4.31)s, respectively, and the CDE were 11.57%±5.21% and 10.68%±6.02%, respectively. The differences between them were not statistically significant (all P>0.05).There were no significant differences in EPT and CDE between groups A1 and B1 (all P>0.05), and there were statistically significant differences between groups A2 and B2, A3 and B3 (all P<0.05).The postoperative CCT was increased in both groups.There were no statistically significant differences in CCT between A1 and B1 groups at different time after surgery (all P>0.05), and there were statistically significant differences in CCT between A2 and B2, A3 and B3 groups at 1 day and 1 week after surgery (all P<0.05), and group B was significantly lower than group A.There was no significant difference between 1 month and 3 months after surgery (P>0.05).ECD was reduced in both groups.There was no statistically significant difference in ECD at different time of operation between A1 and B1 groups (all P>0.05), while there was statistically significant difference in ECD at 1 day, 1 week, 1 month and 3 months after operation in A2 and B2, A3 and B3 groups (all P<0.05). Group B was significantly better than group A. There was no significant difference in coefficient of variation and HEX between the two groups at different time after surgery (P>0.05). Conclusion: Femtosecond laser-assisted phacoemulsification demonstrates benefits in preserving corneal endothelial cells, reducing early postoperative corneal edema, and minimizing corneal injury in type 2 diabetes patients with cataracts of high nuclear hardness.

Feasibility study of wearable capillary refill time measurement device

AbstractCapillary refill time (CRT) is an internationally accepted indicator of peripheral circulation. The CRT is measured by applying compression to the fingernail for a few seconds, releasing it, and observing the process of refilling of blood at the fingertip. The international guidelines for the management of sepsis and septic shock 2021 contains an additional new recommendation for CRT measurement to determine the peripheral circulation statuses of adult patients with septic shock. However, the current CRT measurement method lacks objectivity. Previous studies have reported the development of measurement devices and video analysis systems, which involve complex measurement environment construction and assume only in-hospital measurements. In addition, since medical workers are limited in the number of carrying medical devices, devices that can be used to obtain multiple biometric indicators in a single measurement are needed. Hence, a prototype wearable CRT measurement device was developed in this study, and its feasibility was evaluated by comparing the agreement, intra-class correlation coefficient, and coefficient of variation with those of a CRT measurement device developed in the past. The results indicated that mean CRTs between measurement methods were agreement, with moderate or better intra-rater reliability and no difference in coefficient of variation. Therefore, the results indicate the feasibility of the proposed wearable CRT device.

Corneal endothelial cell changes after phacoemulsification cataract surgery in eyes with different anterior chamber depth: A specular microscopy study

Background: Phacoemulsification surgery is performed in a limited space, therefore, anatomy and procedural parameters, such as sufficient anterior chamber depth (ACD), are essential for protecting endothelial cells during surgery from mechanical and heat damage. Specular microscope is a useful non-contact investigational technique that photographs the human corneal endothelium. Methods: This a prospective comparative cohort non-randomized study included sixty eyes of phacoemulsification cataract surgery were collected from the outpatient clinics of Tanta University Hospitals and were admitted to Ophthalmology Department. Cases were divided into three groups according to ACD. All cases were subjected to: history taking, examination [visual acuity (VA), slit lamp examination, ACD measurement using IOL master, and Specular microscopy.Results: The percentage of endothelial cell loss was much increased in the group A than in the group There was statistically significant increase in the mean CCT in the three groups post-operatively at 1week and 1month compared to pre-operative mean CCT. However, there was no notable differences in CCT among the three groups. There was no notable differences in Coefficient of variation (CV) among the three ACD groups over the entire study period.Conclusions: taking in consideration the ACD as a very important prognostic factor to be considered before phacoemulsification cataract surgery. Eyes with shallow ACs can be vulnerable to more corneal endothelial cell loss during phacoemulsification surgery.

Adaptation to a limiting element involves mitigation of multiple elemental imbalances.

About 20 elements underlie biology and thus constrain biomass production. Recent systems-level observations indicate that altered supply of one element impacts the processing of most elements encompassing an organism (i.e. ionome). Little is known about the evolutionary tendencies of ionomes as populations adapt to distinct biogeochemical environments. We evolved the bacterium Serratia marcescens under five conditions (i.e. low carbon, nitrogen, phosphorus, iron or manganese) that limited the yield of the ancestor compared with replete medium, and measured the concentrations and use efficiency of these five, and five other elements. Both physiological responses of the ancestor, as well as evolutionary responses of descendants to experimental environments involved changes in the content and use efficiencies of the limiting element, and several others. Differences in coefficients of variation in elemental contents based on biological functions were evident, with those involved in biochemical building (C, N, P, S) varying least, followed by biochemical balance (Ca, K, Mg, Na), and biochemical catalysis (Fe, Mn). Finally, descendants evolved to mitigate elemental imbalances evident in the ancestor in response to limiting conditions. Understanding the tendencies of such ionomic responses will be useful to better forecast biological responses to geochemical changes.

Lower motor unit discharge rates in gastrocnemius lateralis, but not in gastrocnemius medialis or soleus, in runners with Achilles tendinopathy: a pilot study.

Deficits in muscle performance could be a consequence of a reduced ability of a motor neuron to increase the rate in which it discharges. This study aimed to investigate motor unit (MU) discharge properties of each triceps surae muscle (TS) and TS torque steadiness during submaximal intensities in runners with Achilles tendinopathy (AT). We recruited runners with (n = 12) and without (n = 13) mid-portion AT. MU discharge rate was analysed for each of the TS muscles, using high-density surface electromyography during 10 and 20% isometric plantar flexor contractions. MU mean discharge rate was lower in the gastrocnemius lateralis (GL) in AT compared to controls. In AT, GL MU mean discharge rate did not increase as torque increased from 10% peak torque, 8.24 pps (95% CI 7.08 to 9.41) to 20%, 8.52 pps (7.41 to 9.63, p = 0.540); however, in controls, MU discharge rate increased as torque increased from 10%, 8.39 pps (7.25-9.53) to 20%, 10.07pps (8.89-11.25, p < 0.001). There were no between-group difference in gastrocnemius medialis (GM) or soleus (SOL) MU discharge rates. We found no between-group differences in coefficient of variation of MU discharge rate in any of the TS muscles nor in TS torque steadiness. Our data demonstrate that runners with AT may have a lower neural drive to GL, failing to increase MU discharge rate to adjust for the increase in torque demand. Further research is needed to understand how interventions focussing on increasing neural drive to GL would affect muscle function in runners with AT.

Deep progressive learning achieves whole-body low-dose 18F-FDG PET imaging

ObjectivesTo validate a total-body PET-guided deep progressive learning reconstruction method (DPR) for low-dose 18F-FDG PET imaging.MethodsList-mode data from the retrospective study (n = 26) were rebinned into short-duration scans and reconstructed with DPR. The standard uptake value (SUV) and tumor-to-liver ratio (TLR) in lesions and coefficient of variation (COV) in the liver in the DPR images were compared to the reference (OSEM images with full-duration data). In the prospective study, another 41 patients were injected with 1/3 of the activity based on the retrospective results. The DPR images (DPR_1/3(p)) were generated and compared with the reference (OSEM images with extended acquisition time). The SUV and COV were evaluated in three selected organs: liver, blood pool and muscle. Quantitative analyses were performed with lesion SUV and TLR, furthermore on small lesions (≤ 10 mm in diameter). Additionally, a 5-point Likert scale visual analysis was performed on the following perspectives: contrast, noise and diagnostic confidence.ResultsIn the retrospective study, the DPR with one-third duration can maintain the image quality as the reference. In the prospective study, good agreement among the SUVs was observed in all selected organs. The quantitative results showed that there was no significant difference in COV between the DPR_1/3(p) group and the reference, while the visual analysis showed no significant differences in image contrast, noise and diagnostic confidence. The lesion SUVs and TLRs in the DPR_1/3(p) group were significantly enhanced compared with the reference, even for small lesions.ConclusionsThe proposed DPR method can reduce the administered activity of 18F-FDG by up to 2/3 in a real-world deployment while maintaining image quality.

Reproducibility of sequential ambulatory blood pressure and pulse wave velocity measurements in normotensive and hypertensive individuals.

Errors in blood pressure (BP) measurement account for a large proportion of misclassified hypertension diagnoses. Ambulatory blood pressure monitoring (ABPM) is often considered to be the gold standard for measurement of BP, but uncertainty remains regarding the degree of measurement error. The aim of this study was to determine reproducibility of sequential ABPM in a population of normotensive and well controlled hypertensive individuals. Individual participant data from three randomized controlled trials, which had recorded ABPM and carotid-femoral pulse wave velocity (PWV) at least twice were combined ( n = 501). We calculated within-individual variability of daytime and night-time BP and compared the variability between normotensive ( n = 324) and hypertensive ( n = 177) individuals. As a secondary analysis, variability of PWV measurements was also calculated, and multivariable linear regression was used to assess characteristics associated with blood pressure variability (BPV). Within-individual coefficient of variation (CoV) for systolic BP was 5.4% (day) and 7.0% (night). Equivalent values for diastolic BP were 6.1% and 8.4%, respectively. No statistically significant difference in CoV was demonstrated between measurements for normotensive and hypertensive individuals. Within-individual CoV for PWV exceeded that of BP measurements (10.7%). BPV was associated with mean pressures, and BMI for night-time measurements. PWV was not independently associated with BPV. The variability of single ABPM measurements will still yield considerable uncertainty regarding true average pressures, potentially resulting in misclassification of hypertensive status and incorrect treatment regimes. Repeated ABPM may be necessary to refine antihypertensive therapy.

Error propagation of climate model rainfall to streamflow simulation in the Gidabo sub-basin, Ethiopian Rift Valley Lakes Basin

ABSTRACT This study assesses bias error of rainfall from climate models and related error propagation effects to simulated streamflow in the Gidabo sub-basin, Ethiopia. Rainfall is obtained from a combination of four global and regional climate models (GCM-RCMs), and streamflow is simulated by means of the Hydrologiska Byråns Vattenbalansavdelning (HBV-96) rainfall-runoff model. Five bias correction methods were tested to reduce the rainfall bias. To assess the effects of rainfall bias error propagation, percent bias (PBIAS), difference in coefficient of variation (CV), and 10th and 90th percentile indicators were applied. Findings indicate that the bias of the uncorrected rainfall caused large errors in simulated streamflow. All five bias correction methods improved the HBV-96 model performance in terms of capturing the observed streamflow. Overall, the findings of this study indicate that the magnitude of the error propagation varies subject to the selected performance indicator, bias correction method and climate model.

Electromyographic measures of asymmetric muscle control of swallowing in Parkinson's disease.

During the early stages, Parkinson's disease (PD) is well recognized as an asymmetric disease with unilateral onset of resting tremor with varying degrees of rigidity, and bradykinesia. However, it remains unknown if other impairments, such as swallowing impairment (i.e., dysphagia), also present asymmetrically. The primary aim of this study was to examine muscle activity associated with swallow on the most affected side (MAS) and least affected side (LAS) in persons with PD. A secondary aim was to explore the relationship between differences in muscle activity associated with swallow and subjective reports of swallowing impairment and disease severity. Function of muscles associated with swallowing was assessed using surface electromyography placed over the right and left submental and laryngeal regions during three swallows for a THIN and THICK condition. The Swallowing Quality of Life (SWAL-QOL) questionnaire and the Unified Parkinson's Disease Rating Scale (UPDRS) were collected as measures of subjective swallow impairment and disease severity, respectively. Thirty-five participants diagnosed with idiopathic PD and on a stable antiparkinsonian medication regimen completed this study. Results revealed no significant mean difference in muscle activity during swallow between the more and less affected side. For the laryngeal muscle region, a significant difference in coefficient of variation between the MAS and LAS was revealed for peak amplitude for the THIN swallow condition. For the laryngeal muscle region, a significant association was revealed between muscle activity and disease severity but not subjective reports of swallowing impairment. Superficially it appears that swallowing impairment present symmetrical during the early stages of PD, however, our variability data indicates otherwise. These results will be used to inform future studies in specific types of swallowing impairment (i.e., oral dysphagia, pharyngeal dysphagia, and esophageal dysphagia), disease progression, and overall asymmetry.

The impact of real-time feedback by deep learning during echocardiographic scanning on test-retest variability of left ventricular systolic function measurements

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Norwegian University of Science and Technology, St. Olavs University Hospital, Central-Norway Health Authority OnBehalf Department of Circulation and Medical imaging, Norwegian University of Science and Technology, Trondheim, Norway Background/introduction Left ventricular (LV) ejection fraction (EF) is the most widely used measure of systolic cardiac function. LV foreshortening is a common problem within echocardiography and cause inaccuracies in estimation of EF and end-diastolic volume (EDV). Guidance of LV length during scanning could improve quality but has not yet been available. Purpose To evaluate the impact of real-time feedback using a robust deep learning (DL) tool during echocardiographic scanning to reduce test-retest variability in assessment of EF and LV EDV. Methods Patients scheduled for echocardiography were included if they were in sinus rhythm and had no need for use of contrast. Three consecutive echocardiograms were performed, where the first and second by two of three experienced sonographers and the third (reference) by one of four cardiologists in random order. Data collection was divided into two periods. In the first period, sonographers were told to provide high quality echocardiograms for analyses of LV function and no additional tool was provided. Thereafter, the sonographers were trained in use of the DL algorithm on 10 patients each. In the second period of inclusion, the real-time DL was used during scanning by the sonographers performing the second exam (Sonographer 2), while the first (Sonographer 1) had participated in training but had no access to the DL tool. All exams included the standard apical views, and the reference exams included tri-plane recordings of the LV as well. All measurements were done retrospectively blinded to the others. LV EF and EDV were measured in four- and two-chamber views and averaged by the method of discs’ formula. The coefficients of variation (CoV) were compared for both LV EF and EDV (two groups of sonographers vs cardiologist) before and after the introduction of DL. Results A total of 88 patients were included (45% women), 41 in period 1 and 47 in period 2. Mean (SD) age was 63 (16) years, LV EF was 53 (12) % and LV EDV was 126 (55) ml. Main findings are shown in the table. There was no significant difference in CoV for neither LV EF nor EDV using the DL tool. Compared to the first period the sonographers not using the DL tool had poorer reproducibility of LV EDV in period 2 (p ≤0.02), while there was a trend for reduced CoV for LV EDV for those using the algorithm (p = 0.11). By using the DL algorithm, LV foreshortening was reduced by 2.4 mm (p &amp;lt;0.001), and similarly, alignment of the mitral annulus was numerically improved (p = 0.10). Whether other markers of image quality were changed is not known. Conclusion The novel real-time DL algorithm to reduce foreshortening provided more standardized recordings when used by experienced sonographers during scanning, but these changes did not result in significant improvement in test-retest variation. Further development and investigations are needed to significantly reduce test-retest variability. Abstract Table_1 Abstract Figure. DL_tool

Effect of a Hybrid Closed-Loop System on Glycemic and Psychosocial Outcomes in Children and Adolescents With Type 1 Diabetes

Hybrid closed-loop (HCL) therapy has improved glycemic control in children and adolescents with type 1 diabetes; however, the efficacy of HCL on glycemic and psychosocial outcomes has not yet been established in a long-term randomized clinical trial. To determine the percentage of time spent in the target glucose range using HCL vs current conventional therapies of continuous subcutaneous insulin infusion or multiple daily insulin injections with or without continuous glucose monitoring (CGM). This 6-month, multicenter, randomized clinical trial included 172 children and adolescents with type 1 diabetes; patients were recruited between April 18, 2017, and October 4, 2019, in Australia. Data were analyzed from July 25, 2020, to February 26, 2021. Eligible participants were randomly assigned to either the control group for conventional therapy (continuous subcutaneous insulin infusion or multiple daily insulin injections with or without CGM) or the intervention group for HCL therapy. The primary outcome was the percentage of time in range (TIR) within a glucose range of 70 to 180 mg/dL, measured by 3-week masked CGM collected at the end of the study in both groups. Secondary outcomes included CGM metrics for hypoglycemia, hyperglycemia, and glycemic variability and psychosocial measures collected by validated questionnaires. A total of 135 patients (mean [SD] age, 15.3 [3.1] years; 76 girls [56%]) were included, with 68 randomized to the control group and 67 to the HCL group. Patients had a mean (SD) diabetes duration of 7.7 (4.3) years and mean hemoglobin A1c of 64 (11) mmol/mol, with 110 participants (81%) receiving continuous subcutaneous insulin infusion and 72 (53%) receiving CGM. In the intention-to-treat analyses, TIR increased from a mean (SD) of 53.1% (13.0%) at baseline to 62.5% (12.0%) at the end of the study in the HCL group and from 54.6% (12.5%) to 56.1% (12.2%) in the control group, with a mean adjusted difference between the 2 groups of 6.7% (95% CI, 2.7%-10.8%; P = .002). Hybrid closed-loop therapy also reduced the time that patients spent in a hypoglycemic (<70 mg/dL) range (difference, -1.9%; 95% CI, -2.5% to -1.3%) and improved glycemic variability (coefficient of variation difference, -5.7%; 95% CI, -10.2% to -0.9%). Hybrid closed-loop therapy was associated with improved diabetes-specific quality of life (difference, 4.4 points; 95% CI, 0.4-8.4 points), with no change in diabetes distress. There were no episodes of severe hypoglycemia or diabetic ketoacidosis in either group. In this randomized clinical trial, 6 months of HCL therapy significantly improved glycemic control and quality of life compared with conventional therapy in children and adolescents with type 1 diabetes. ANZCTR identifier: ACTRN12616000753459.

Interocular Symmetry and Repeatability of Central Corneal Thickness and Corneal Endothelial Cell Morphology and Density in Healthy Eyes of Congolese

ABSTRACT Purpose To determine the limits of normal interocular symmetry and the repeatability of central corneal thickness (CCT) and endothelial cell morphology and density. Methods Two hundred and seventy-eight subjects (age: 10.9–80.7 years) with healthy eyes were studied. CCT as well as endothelial cell morphology and density were measured by non-contact specular microscopy. Three measurements were obtained per eye per participant. Upper and lower tolerance limits of normal interocular symmetry were defined as the 2.5th and 97.5th percentiles of the interocular differences in CCT, endothelial cell density (CECD), coefficient of variation (CoV), hexagonality, and cell size. Repeatability was determined using the intraclass coefficient correlation (ICC), the coefficient of variation (CV), and the test–retest variability standard deviation (TRTSD). Results The mean interocular differences were −1.05 ± 17.5 µm (p = .32) for CCT and 0.5 ± 90.8 cells/mm2 (p = .76) for CECD. The 2.5th and 97.5th percentiles of the interocular differences were −13.9 and 15.4 µm for CCT and −177.4 cells/mm2 to 182.0 cells/mm2 for CECD. Only interocular difference in CoV correlated weakly with age (r = −0.22, P < .001). ICCs were 0.93 (95% CI: 0.89–0.96, P < .001) for CCT and 0.95 (0.94–0.96, P < .001) for CECD. CV and TRTSD were 1.2% ± 5.3% and 4.4 ± 3.4 µm for CCT and 2.4% ± 3.9% and 17.7 ± 7.7 cells/mm2 for CECD, respectively. Conclusions CCT and CECD showed good repeatability and interocular symmetry in normal Congolese subjects. Absolute interocular differences in CCT and CECD exceeding 15.5 µm and 182 cells/mm2, respectively, should be considered suspicious and investigated. When comparing two intrasession measurements from the same eye, a difference of approximately 4.5 µm in CCT and 18 cells/mm2 or greater may be considered statistically significant.

Assessing between and within Product Group Variance of Environmental Efficiency of Swiss Agriculture Using Life Cycle Assessment and Data Envelopment Analysis

Food production systems can contribute to the degradation of the environment; thereby endangering the very resource, they depend on. However, while overall large, the environmental impacts of individual agricultural products are disparate. Therefore, in order to gain a better understanding of the impact different food production systems have on the environment, we should start at the produce level. In this study, we combine life cycle assessment (LCA) methodology and data envelopment analysis to calculate environmental efficiency scores (i.e., agricultural output divided by environmental impacts) for eight product groups (Milk, Cattle, Pig fattening, Cereals, Beets, Potatoes, Vegetables, Fruits) in Switzerland. First, LCA is used to calculate “cradle to farm-gate” environmental impacts. These impacts are then used as inputs in a data envelopment analysis, with the amount of produced agricultural products as outputs. The resulting environmental efficiency scores reflect the relative efficiency (i.e., related to the best-observed performance) of the observed product groups. We find large differences in environmental impacts and environmental efficiency score distribution between the product groups. While we find some variability of environmental efficiency between farming systems (Organic and Proof of Ecological Performance) within a product group (difference in coefficient of variation between farming systems: Fruits = 48%, Vegetables = 13%, Cereals, Potatoes = 8%), we did not find any significant differences in environmental efficiency between organic and integrated farming systems for any of the considered product groups. Furthermore, we did not find a negative effect of multifunctionality of Swiss farms (i.e., multiple simultaneously produced product groups), but found a small positive effect for Milk in the presence of other product groups. However, the high within product group variance of environmental efficiency suggests the potential for improvements (notably &gt;40% for Fruits and &gt;30% for Cattle and Potatoes).

Intraindividual variability in driving simulator parameters of healthy drivers of different ages

Intraindividual variability is a fundamental behavioural characteristic of aging but has been examined to a very limited extent in driving. This study investigated intraindividual variability in driving simulator measures in healthy drivers of different ages using the coefficient of variation (COV) as a variability measure. Participants were healthy volunteers who were regular drivers, who were divided into a “young” group, a “middle-aged” group, and an “old” group. They drove in two environments (rural, 72 drivers; urban, 60 drivers), under conditions of moderate and high traffic load, without and with distraction (conversation). Significant differences in COV were observed in the rural condition for headway distance and lateral position as a function of traffic load, with high traffic (without and with distraction) resulting in increased COV of headway and decreased COV of lateral position. Significant differences in COV were observed in the urban condition for headway distance only, with high traffic (without and with distraction) resulting in increased COV of headway. No age effects were found for any of the driving conditions. The results indicate that traffic load affected headway distance and lateral position in opposite directions in all three age groups: high traffic resulted in increased variability of headway in both rural and urban conditions but in decreased variability of lateral position in the rural conditions compared to moderate traffic irrespective of distraction. The study indicates that driving conditions affect the intraindividual variability of driving measures in selective ways, which may be linked to the extent of automatization of the driving variables and to adaptive changes to traffic condition challenges.

A Novel Assessment Technique Does Not Produce More Reliable Estimates of Maximal Neuromuscular Strength

ABSTRACT Accurate determinations of individuals’ one-repetition maximum (1RM) are critical when evaluating the effectiveness of an exercise intervention involving progressive resistance training (RT). Traditional (“bottom-up”; BT) testing methods involve progressions from low to maximal loads and are commonly used in clinical and laboratory environments. Concerns about the reliability of BT testing in certain populations suggest a different technique may be more effective. Purpose: To compare the reliability and effectiveness of traditional 1RM testing to a novel technique (TDT) involving progressive load reductions and a starting intensity equal to 130% of exercisers’ estimated 1RM. Method: 70 healthy adults (age = 45.03 ± 25.64 y) with diverse RT experience were randomized into a reliability testing trial (RTT; n = 33) or an optimal method trial (OMT; n = 37). Subjects in the RTT performed either TDT or BT on 3 occasions separated by ≥ 72 hours, while subjects in the OMT performed each method once in random order on separate days. Results: No significant differences in percent coefficient of variation were observed between BT and TDT for either exercise used in the study (pneumatic seated chest press: Hedge’s g = 0.25, p = .49; pneumatic recumbent leg press: Hedge’s g = 0.12, p = .74). TDT was not found to produce significantly higher 1RM values than BT in any group. Conclusion: TDT does not appear to facilitate more reliable 1RM estimates than BT. Further research is needed to determine the stability of these findings across levels of exercisers’ age, sex, and previous RT experience.

1017-P: Effects of the T:slim X2 Insulin Pump with Basal-IQ Technology on Glycemic Control in a Pediatric Urban Academic Diabetes Practice

The predictive low glucose suspend (PLGS) algorithm of the t:slimx2 insulin pump with Basal-IQ technology, which is used with the Dexcom G6 continuous glucose monitor (CGM), has been shown to reduce hypoglycemia, though the effect on glucose variability longitudinally in a real-world pediatric population is unknown. We hypothesized that children and adolescents who obtain their care at an urban, academic diabetes center and use the PLGS algorithm would have improved glycemic outcomes, compared to their previous method of diabetes care. We recruited pediatric patients aged 6-18 years old with T1D for &amp;gt;1 year prior to starting the PLGS system. At baseline, glycemic control was assessed using CGM or fingerstick glucose metrics. For the 3 month timepoint, Tandem T:connect software was used. Of the 97 pediatric patients at our center with T1D for &amp;gt;1 year using the PLGS system, 41 pediatric subjects (51.2% female) with a median age of 13.6 years (range 6.6-17.8) and 3 month follow-up data were eligible for analysis. Baseline CSII and CGM use were 87.8% and 92.7%, respectively. Subjects were using Basal-IQ for a median of 92% of the time with 6 suspensions per day in the 2 weeks prior to 3 month follow-up. HbA1c, mean glucose, and percent time in range improved from 7.5%, 186 mg/dl and 51.9% on their previous diabetes care to 7.35%, 171 mg/dl and 57% after 3 months of Basal-IQ use (p= 0.005, p=0.03 and p=0.001). Percent time glucose below 55 mg/dl was a median of 0% at baseline and also at follow-up. There were no significant differences in coefficient of variation, percent time glucose below 70 mg/dl, and percent time glucose above 180 mg/dl. There were also no episodes of DKA or severe hypoglycemia after initiation of Basal-IQ in this cohort. The t:slim x2 insulin pump with Basal-IQ technology resulted in improved HbA1c, mean glucose, and percent time in range in pediatric patients after 3 months of use, without an increase in hypoglycemia or adverse events. 6 month data is being analyzed. Disclosure A. Weiner: None. E. Robinson: None. R. Gandica: None. Funding National Institutes of Health (T32DK065522-14)

Observation on death of MHD patients with different blood phosphorus variation coefficients

Objective To investigate the death of MHD patients with different blood phosphorus variability. Methods The clinical data of seventy-four cases of MHD patients with more than 3 months dialysis age in the hemodialysis center of Chaozhou Central Hospital from January 2014 to December 2016 were retrospectively analyzed.The general data and laboratory biochemical indexes were collected and according to the difference in coefficient of variation (CV), the patients were divided into two groups: high blood phosphorus variability group (CV≥0.226 mmol/L) and low blood phosphorus variability group (CV<0.226 mmol/L). The relationship between the coefficient of variation and all-cause mortality and cardiovascular mortality in MHD patients was analyzed. Results Among all selected patients, all-cause mortality rate was 22.9%(17/24), 12.2%(9/74) died of cardiovascular disease, and the all-cause mortality 34.2%(13/38)in the high blood phosphorus variability group was significantly higher than that in the other one11.1%(4/36) (χ2=5.574, P 0.05). And there was no significant difference between the serum phosphorus standard group and the substandard group in the all-cause mortality and the cardiovascular disease mortality (χ2=0.389, 0.065, P>0.05). There was no significant difference in the cumulative survival rate between the patients in the serum phosphorus standard group who experienced all-cause death and cardiovascular disease death and the patients in the substandard group (P>0.05). In the high blood phosphorus variability group, patients who reached serum phosphorus standard had higher total mortality rate and cardiovascular disease mortality rate, compared with patients who achieved serum phosphorus standard or experienced low phosphorus deficiency in the low blood phosphorus variability group (χ2=0.211, 0.197, P>0.05). Kaplan/Meier analysis showed that the cumulative survival rates of all patients with all-cause death and cardiovascular death in the high blood phosphorus variability group were significantly lower than those in the low level group (P<0.05). Conclusion All-cause mortality and cardiovascular disease mortality are high in MHD patients with large variability in blood phosphorus, and the degree of blood phosphorus variation is helpful to predict the death of MHD patients. Key words: Phosphorus; Maintenance hemodialysis; Mortality; Variation coeffic

Home sperm testing device versus laboratory sperm quality analyzer: comparison of motile sperm concentration

To test the ability of the smartphone-based YO Home Sperm Test to accurately and precisely measure motile sperm concentration (MSC) versus the SQA-Vision, an automated laboratory semen analyzer. MSC compared for the YO device on Galaxy and iPhone smartphones versus the SQA-Vision in a double-blind manner. Academic medical center. Donor semen samples from 24 men in 144 aliquots. None. Accuracy, precision, and agreement assessed between the YO device and the SQA-Vision for MSC results. The YO device demonstrated good correlation and good to moderate agreement with the SQA-Vision for MSC results up to a range of 94 × 106/mL with Pearson and concordance correlation coefficient above 0.92. The YO also showed a very high level of accuracy (97.8%) with positive and negative percent agreement above 94%. The difference in coefficient of variation between the YO and the SQA-Vision was low (between 9.4% and 11.2%) and not statistically significant. The precision among the YO phone devices was lower (16.0%) than the manufacturer's claim of ≤20%. The smartphone-based device has a high level of accuracy and precision when compared with the SQA-Vision. It can detect samples with abnormally "low" MSC (below 6 × 106/mL cutoff), which supports its use as an effective home sperm test for screening "low" and "moderate/normal" MSC cases. In addition, the device effectively identifies varying levels of normal MSC in a precise manner over a wide range of normal MSC. Thus, the YO Score can improve patient satisfaction and empowerment.

Springs as hydrologic refugia in a changing climate? A remote‐sensing approach

AbstractSpring‐fed wetlands are ecologically important habitats in arid and semi‐arid regions. Springs have been suggested as possible hydrologic refugia from droughts and climate change; however, springs that depend on recent precipitation or snowmelt for recharge may be vulnerable to warming and drought intensification. Springs that are expected to maintain their ecohydrologic function in a warmer, drier climate may be priorities for conservation and restoration. Identifying such springs is difficult because many springs lack hydrologic records of adequate temporal extent and resolution to assess their resilience to water cycle changes. This study demonstrates proof‐of‐concept for the assessment of certain spring types (i.e., helocrene, hypocrene, and hillslope springs) in terms of hydrologic and ecological resilience to climatic water stress using freely available remote‐sensing and climate data. We used the Normalized Difference Vegetation Index (NDVI) from 1985 through 2011 to delineate surface‐moisture zones (SMZs) associated with 39 clusters of 172 springs in a montane sage‐steppe landscape in southeastern Oregon, USA. We developed and synthesized seven NDVI‐based indicators of SMZ resilience to interannual changes in water availability: (1) mean and (2) standard deviation of July NDVI; (3) mean difference in July NDVI and (4) difference in coefficient of variation for July NDVI between each SMZ and its surrounding watershed; (5) response of SMZ July NDVI to 90‐day antecedent precipitation; (6) response of SMZ July NDVI to the previous winter's snowpack; and (7) range of NDVI values from an exceptionally wet year followed by three dry years. Because all resilience indicators were highly inter‐correlated, we derived an overall metric of SMZ resilience using principal components analysis that accounted for 66% of total variance. This overall resilience score was positively correlated with SMZ elevation, slope, mean annual precipitation, and with the number of associated springs. Resilience was greater for SMZs on topographically shaded, north‐facing slopes. Several high‐resilience SMZs were located immediately below persistent snowbanks, suggesting a possible source of steady recharge throughout the growing season. The approach presented here—if combined with field assessments of spring hydrogeology, discharge, and groundwater age—could help identify spring‐fed wetlands that are most likely to serve as hydrologic refugia from climate change.