Greater Root Mean Square Research Articles

Aluminum's role in tailoring the characteristics of room temperature co-sputtered gadolinium and aluminum-doped ZnO thin films

This study investigated the characteristics of gadolinium (Gd) and aluminum (Al) co-doped ZnO synthesized by co-sputtering at varying concentrations of Al. FESEM images revealed a morphology containing spherical-hexagonal nanostructures of different sizes based on the amount of Al. The EDS spectra clearly demonstrated the presence of Al, Gd, Zn, and O, confirming the successful incorporation of Gd and Al ions into the ZnO lattice in agreement with XRD profiles, not detecting any secondary phases. The photoluminescence study revealed that doping-induced defect states (oxygen vacancies, zinc vacancies, and zinc interstitial) were responsible for the many characteristic peaks of deep level emission observed in the photoluminescence spectra. Higher Al doping induced changes in magnetic characteristics as reflected in the greater root mean square value (δfrms), and the root mean square phase shift value (Φrms) in MFM analysis, whereas the magnetic correlation length (L) decreases. The incorporation of Al at higher concentrations into Gd-doped ZnO resulted in improved magnetic behavior suggesting the exchange interaction between Gd and Al ions mediated by oxygen vacancies. These results confirm that sufficient Al doping can efficiently improve the properties and magnetic behavior of ZnO-based DMS systems, which could potentially pave the way towards the realization of spin and/or optical based electronic devices.

Cross-frequency modulation of postural fluctuations and scalp EEG in older adults: error amplification feedback for rapid balance adjustments.

Virtual error amplification (VEA) in visual feedback enhances attentive control over postural stability, although the neural mechanisms are still debated. This study investigated the distinct cortical control of unsteady stance in older adults using VEA through cross-frequency modulation of postural fluctuations and scalp EEG. Thirty-seven community-dwelling older adults (68.1 ± 3.6years) maintained an upright stance on a stabilometer while receiving either VEA or real error feedback. Along with postural fluctuation dynamics, phase-amplitude coupling (PAC) and amplitude-amplitude coupling (AAC) were analyzed for postural fluctuations under 2Hz and EEG sub-bands (theta, alpha, and beta). The results revealed a higher mean frequency of the postural fluctuation phase (p = .005) and a greater root mean square of the postural fluctuation amplitude (p = .003) with VEA compared to the control condition. VEA also reduced PAC between the postural fluctuation phase and beta-band EEG in the left frontal (p = .009), sensorimotor (p = .002), and occipital (p = .018) areas. Conversely, VEA increased the AAC of posture fluctuation amplitude and beta-band EEG in FP2 (p = .027). Neither theta nor alpha band PAC or AAC were affected by VEA. VEA optimizes postural strategies in older adults during stabilometer stance by enhancing visuospatial attentive control of postural responses and facilitating the transition of motor states against postural perturbations through a disinhibitory process. Incorporating VEA into virtual reality technology is advocated as a valuable strategy for optimizing therapeutic interventions in postural therapy, particularly to mitigate the risk of falls among older adults.

Higher order aberrations according to spherical, and astigmatic refractive errors in children

ABSTRACT Clinical relevance The results of this study present novel insights into the impact of spherical and astigmatic refractive errors on overall, corneal and internal aberrations and may provide a clear understanding of the emmetropisation process and the development of visual function. Background This study aimed to assess the association between overall, corneal and internal higher-order aberrations and the spherical and astigmatic components (magnitude and angle) of refractive error in a large sample of children. Methods A total of 311 children aged 7 – 8 years old were classified based on spherical equivalent refraction (myopic, emmetropic and hyperopic); magnitude of astigmatism (none, low and moderate); and angle of astigmatism (with-the-rule, against-the-rule and oblique). Refractive error and overall, corneal and internal higher-order aberrations were measured using the OPD-Scan III workstation. Results Regarding spherical equivalent refraction, myopic eyes had greater root mean square (RMS) overall higher-order values, total spherical, tetrafoil and secondary astigmatism aberrations, and internal higher-order, total spherical and tetrafoil aberrations in comparison to emmetropic eyes. The magnitude of astigmatism was positively associated with all overall RMS aberrations and with internal higher order, coma, total coma, total spherical and tetrafoil aberrations. Eyes with with-the-rule astigmatism showed higher RMS values of coma and total coma compared to eyes with against-the-rule and oblique astigmatism. Conclusions Higher-order aberrations are dependent on the spherical as well as astigmatic components of refractive error. These findings enhance the current understanding of the emmetropisation process and visual function development.

Quantification and prediction of enteric methane emissions from Chinese lactating Holstein dairy cows fed diets with different dietary neutral detergent fiber/non-fibrous carbohydrate (NDF/NFC) ratios

Methane (CH4) emissions from ruminant production are a significant source of anthropogenic greenhouse gas production, but few studies have examined the enteric CH4 emissions of lactating dairy cows under different feeding regimes in China. This study aimed to investigate the influence of different dietary neutral detergent fiber/non-fibrous carbohydrate (NDF/NFC) ratios on production performance, nutrient digestibility, and CH4 emissions for Holstein dairy cows at various stages of lactation. It evaluated the performance of CH4 prediction equations developed using local dietary and milk production variables compared to previously published prediction equations developed in other production regimes. For this purpose, 36 lactating cows were assigned to one of three treatments with differing dietary NDF/NFC ratios: low (NDF/NFC = 1.19), medium (NDF/NFC=1.54), and high (NDF/NFC=1.68). A modified acid-insoluble ash method was used to determine nutrient digestibility, while the sulfur hexafluoride technique was used to measure enteric CH4 emissions. The results showed that the dry matter (DM) intake of cows at the early, middle, and late stages of lactation decreased significantly (P<0.01) from 20.9 to 15.4 kg d−1, 15.3 to 11.6 kg d−1, and 16.4 to 15.0 kg d−1, respectively, as dietary NDF/NFC ratios increased. Across all three treatments, DM and gross energy (GE) digestibility values were the highest (P<0.05) for cows at the middle and late lactation stages. Daily CH4 emissions increased linearly (P<0.05), from 325.2 to 391.9 kg d−1, 261.0 to 399.8 kg d−1, and 241.8 to 390.6 kg d−1, respectively, as dietary NDF/NFC ratios increased during the early, middle, and late stages of lactation. CH4 emissions expressed per unit of metabolic body weight, DM intake, NDF intake, or fat-corrected milk yield increased with increasing dietary NDF/NFC ratios. In addition, CH4 emissions expressed per unit of GE intake increased significantly (P<0.05), from 4.87 to 8.12%, 5.16 to 9.25%, and 5.06 to 8.17% respectively, as dietary NDF/NFC ratios increased during the early, middle, and late lactation stages. The modelling results showed that the equation using DM intake as the single variable yielded a greater R2 than equations using other dietary or milk production variables. When data obtained from each lactation stage were combined, DM intake remained a better predictor of CH4 emissions (R2=0.786, P=0.026) than any other variables tested. Compared to the prediction equations developed herein, previously published equations had a greater root mean square prediction error, reflecting their inability to predict CH4 emissions for Chinese Holstein dairy cows accurately. The quantification of CH4 production by lactating dairy cows under Chinese production systems and the development of associated prediction equations will help establish regional or national CH4 inventories and improve mitigation approaches to dairy production.

Estimation of MUF(3000)F2 using Earth-ionosphere geometry for Karachi and Multan, Pakistan

• Earth-ionosphere geometry is used for MUF estimation with h’F2 replacing hmF2. • Linear regression analysis reduces error in MUF estimation to 2 MHz. • The methodology may be applicable for HF communication support. We report the estimation of the Maximum Usable Frequency of F2-layer for 3000 km circuit ( MUF ( 3000 ) F 2 ) using Earth-ionosphere geometry. The study is based on the assumption that h ′ F 2 may replace hmF 2 to estimate M ( 3000 ) F 2 . The monthly hourly medians of f o F 2 , h ′ F 2 , and M ( 3000 ) F 2 are extracted for Karachi (geog. coord. 24.9 ° N, 67.3 ° E) & Multan (30.2 ° N, 71.5 ° E) during 1996, 1992, & 1989 representing low, moderate & high solar activity years, respectively. The MUF ( 3000 ) F 2 estimated using spherical geometry shows large deviation and greater Root Mean Square Error values (RMSE > 4 MHz) on comparison with MUF ( 3000 ) F 2 observed from ionosonde. In order to reduce the error, linear regression analysis technique is used and applied on independent data set of years 1995, 1993 and 1991 representing low, moderate and high solar activity to compute corrected MUF ( 3000 ) F 2 , respectively. It is found that corrected MUF is in good agreement with observed MUF decreasing RMSE to less than 2.0 MHz for the stations and years under study. The results of this study would be helpful in MUF estimation using h ′ F 2 and also in improving radio services for smooth HF communication.

Action dual tasks reveal differential effects of visual imagery perspectives on motor performance.

Imagery research has identified two main visual perspectives, external visual imagery (EVI, third person) and internal visual imagery (IVI, first person). Based upon findings from brain imaging literature showing that different neural substrates are recruited for IVI and EVI perspectives, and that IVI activates motor system brain areas, we hypothesised that a concurrent action dual task would cause greater interference in performance for IVI than EVI. In a first experiment, participants were allocated to either an IVI or an EVI group, and were tasked with moving an onscreen marker towards a target in three blocked conditions: imagery, imagery with a concurrent motor dual-task of sequencing, and a math control. An interaction between imagery group and condition was driven by greater root mean square error for participants in the dual-task condition in the IVI group compared with the EVI group. We replicated the experiment with an eye-tracking objective measure of IVI; the results again showed that participants in the IVI group made more errors in motor movements, and an interference effect in eye movements, during the dual-task sequencing condition compared with the EVI group. The results of the two experiments reveal that a secondary motor task does interfere with IVI, providing behavioural evidence that IVI appears to rely on motor system processes more than EVI. These results have important implications for the use of visual imagery perspectives across a number of domains, with this paper being an essential reference for those conducting visual imagery perspectives research.

Force and Directional Force Modulation Effects on Accuracy and Variability in Low-Level Pinch Force Tracking

ABSTRACTThe authors investigated how varying the required low-level forces and the direction of force change affect accuracy and variability of force production in a cyclic isometric pinch force tracking task. Eighteen healthy right-handed adult volunteers performed the tracking task over 3 different force ranges. Root mean square error and coefficient of variation were higher at lower force levels and during minimum reversals compared with maximum reversals. Overall, the thumb showed greater root mean square error and coefficient of variation scores than did the index finger during maximum reversals, but not during minimum reversals. The observed impaired performance during minimum reversals might originate from history-dependent mechanisms of force production and highly coupled 2-digit performance.

Flowtaxis of osteoblast migration under fluid shear and the effect of RhoA kinase silencing.

Despite the important role of mechanical signals in bone remodeling, relatively little is known about how fluid shear affects osteoblastic cell migration behavior. Here we demonstrated that MC3T3-E1 osteoblast migration could be activated by physiologically-relevant levels of fluid shear in a shear stress-dependent manner. Interestingly, shear-sensitive osteoblast migration behavior was prominent only during the initial period after the onset of the steady flow (for about 30 min), exhibiting shear stress-dependent migration speed, displacement, arrest coefficient, and motility coefficient. For example, cell speed at 1 min was 0.28, 0.47, 0.51, and 0.84 μm min-1 for static, 2, 15, and 25 dyne cm-2 shear stress, respectively. Arrest coefficient (measuring how often cells are paused during migration) assessed for the first 30 min was 0.40, 0.26, 0.24, and 0.12 respectively for static, 2, 15, and 25 dyne cm-2. After this initial period, osteoblasts under steady flow showed decreased migration capacity and diminished shear stress dependency. Molecular interference of RhoA kinase (ROCK), a regulator of cytoskeletal tension signaling, was found to increase the shear-sensitive window beyond the initial period. Cells with ROCK-shRNA had increased migration in the flow direction and continued shear sensitivity, resulting in greater root mean square displacement at the end of 120 min of measurement. It is notable that the transient osteoblast migration behavior was in sharp contrast to mesenchymal stem cells that exhibited sustained shear sensitivity (as we recently reported, J. R. Soc. Interface. 2015; 12:20141351). The study of fluid shear as a driving force for cell migration, i.e., “flowtaxis”, and investigation of molecular mechanosensors governing such behavior (e.g., ROCK as tested in this study) may provide new and improved insights into the fundamental understanding of cell migration-based homeostasis.

Ocular aberrations in amblyopic children

PurposeTo study the pattern of ocular aberrations in amblyopic children, and evaluate a possible relation to etiology and treatment outcomes of amblyopia. MethodsThe WaveScan Wavefront System (AMO, Santa Ana, CA, USA) aberrometer was used to assess 75 eyes (60 children) after instillation of 1% cyclopentolate eyedrops. There were 29 males and 31 females with a mean age of 9.23±2.55years (range, 5–14years). The study sample was subdivided into four groups; 16 emmetropic non-amblyopic eyes (control group); 24 pre-treatment newly diagnosed amblyopic eyes; 16 eyes of treated amblyopes and; 19 eyes with refractory amblyopia. ResultsAmblyopes had statistically significant greater root mean square (RMS) values for whole eye aberrations, 2nd order aberrations, defocus (Z20) and astigmatism (Z22) compared to emmetropes (P<0.0001). The refractory amblyopic group showed statistically significant differences in whole eye RMS, 2nd order- aberrations, defocus (Z20) and astigmatism (Z22) when compared to treated amblyopic groups (P<0.0001). Apart from a statistically significant difference in 5th order RMS of pre-treated amblyopes versus the control group, no other significant differences were found in higher order aberrations (HOAs: coma, spherical, higher-order astigmatism, trefoil, or 3rd, 4th, 5th or 6th order terms) between emmetropes and any of the amblyopic groups. ConclusionLower order aberrations remain the major factor that affect retinal image quality and hence amblyopia development especially in ametropic eyes. This can be corrected optically. Studying HOA profile in amblyopic eyes failed to explain why refractory amblyopia does not respond to orthoptic treatments. This outcome indicates that theories of central problems in image processing and binocular interaction are likely the main cause of refractory amblyopia.

Novel predictor of prognosis from exercise stress testing: Heart rate variability response to the exercise treadmill test

Although the prognostic power of heart rate variability (HRV) at rest has been demonstrated, the prognostic potential of exercise-induced HRV has not been investigated. We aimed to evaluate the prognostic power of exercise-induced HRV during and after standard exercise testing. Time- and frequency-domain HRV analysis was performed on R-R interval data taken from 1335 subjects (95% male, mean age 58 years) during the first and last 2 minutes of exercise treadmill testing and the first 2 minutes of recovery. Cox survival analysis was performed for the 53 cardiovascular and 133 all-cause mortality end points that accrued during the 5.0-year mean follow-up. After adjusting for potential confounders, greater root mean square successive difference in R-R interval during peak exercise and recovery, greater high-frequency (HF) power and percentage of HF power, lower percentage of low-frequency power, and lower ratio of low frequency to HF during recovery were significantly associated with increased risks for all-cause and cardiovascular death. Of all time-domain variables considered, the log of the root mean square successive difference during recovery was the strongest predictor of cardiovascular mortality (adjusted hazard ratio 5.0, 95% CI 1.5-17.0 for the top quintile compared with the lowest quintile). Log HF power during recovery was the strongest predictor of cardiovascular mortality in the frequency domain (adjusted hazard ratio 5.9, 95% CI 1.3-25.8 for the top quintile compared with the lowest quintile). Exercise-induced HRV variables during and after clinical exercise testing strongly predict both cardiovascular and all-cause mortality independent of clinical factors and exercise responses in our study population.

Application of the Bi‐Factor Multidimensional Item Response Theory Model to Testlet‐Based Tests

Four item response theory (IRT) models were compared using data from tests where multiple items were grouped into testlets focused on a common stimulus. In the bi‐factor model each item was treated as a function of a primary trait plus a nuisance trait due to the testlet; in the testlet‐effects model the slopes in the direction of the testlet traits were constrained within each testlet to be proportional to the slope in the direction of the primary trait; in the polytomous model the item scores were summed into a single score for each testlet; and in the independent‐items model the testlet structure was ignored. Using the simulated data, reliability was overestimated somewhat by the independent‐items model when the items were not independent within testlets. Under these nonindependent conditions, the independent‐items model also yielded greater root mean square error (RMSE) for item difficulty and underestimated the item slopes. When the items within testlets were instead generated to be independent, the bi‐factor model yielded somewhat higher RMSE in difficulty and slope. Similar differences between the models were illustrated with real data.

Thin film properties and surface morphology of metal free phthalocyanine films grown by organic molecular beam deposition

The structure, optical properties and surface morphology of thin films of metal free phthalocyanine (H2Pc) deposited in an ultra-high vacuum environment by organic molecular beam deposition have been studied using a variety of ex-situ techniques. The growth conditions have a strong influence on the properties of the films. H2Pc undergoes a phase transition (α→β) at a deposition temperature of ∽330°C, or upon post annealing a film grown at room temperature. Both the structure and optical properties of the films change and powder X-ray diffraction, electronic absorption spectroscopy, Raman and photoluminescence spectroscopies are used to characterise the differences between the two phases. Atomic force microscopy and Nomarski interference microscopy show that the lower temperature α-phase is characterised by a smooth morphology with spherical islands that show no apparent long-range order. By contrast, the β-phase has a much greater root mean square roughness and long thin needle-like crystals are observed on the surface of the films. The morphology of the β-phase depends on the method of preparation and there are two distinct types, β1 and β2. The crystallites show a preferential orientation and alignment with respect to each other for growth at room temperature followed by annealing (β1), but are randomly oriented for films grown at elevated substrate temperatures (β2).

Exercise effect of modified contralateral stabilization bar during one-legged isokinetic exercise

We compared the electrical activities recorded from the muscles of the unexercised leg with changing the position of the contralateral stabilization bar to determine whether the degree of muscle contraction was influenced by the position of the bar during one-legged isokinetic exercise using an isokinetic dynamometer. The root mean square (RMS) values recorded from the medial hamstring sites of the unexercised legs showed a significantly higher value when the bar was located behind and on both in front of and behind the unexercised leg during one-legged extension exercise. Results from the isokinetic knee flexion exercise test indicated that a significantly greater RMS value was recorded from the vastus lateralis sites when the bar was located in front of and on both sides of the unexercised leg. During one-legged isokinetic extension-flexion exercise, the mean values of RMS voltage were greater when the bar was positioned in front of and on both sides of the unexercised leg in the vastus lateralis site. At the medial hamstring site, a greater value was noticed when the bar was located behind or on both sides.

Molecular Dynamics Simulations of DNA Double Helices: Studies of Sequence Dependence and the Role of Mismatch Pairs in the DNA Helix

AbstractWe present the results of molecular dynamics simulations on base paired deoxyribonucleotides dA10·dT10, d(GCGCGCGCGC)2 d(ATATATATAT)2 d(CGCGA)·d(TCACG) (AC mismatch) and d(CGAGA)·d(TCGCG) (GA mismatch). The average structural properties — helix parameters, H‐bond parameters, sugar puckers, torsional angles, root mean square atomic fluctuations — are compared to those found in earlier studies on the sequence d(CGCGA)·d(TCGCG).1 The properties of the decamer helices remain B DNA like throughout the simulation, confirming our inference1 that a model which treats solvent/counterions in a simple fashion (full charge on phosphates, but use of large hydrated counterions and a distance dependent dielectric constant) is a reasonable “first order” model to simulate the properties of DNA helices over periods of at least 100 psec. There are a number of sequence dependent effects observed in the three decanucleotides studied here, among them differences in H‐bond properties, sugar pucker and helix repeat/base tilts. In d(GCGCGCGCGC)2 and d(ATATATATAT)2 the H‐bonds all stay near the classic Watson‐Crick distance and the base tilts and twists are small (10–20°). On the other hand, in dA10·dT10 there are much larger deviations of H‐bonding from classic Watson‐Crick and H‐bond exchange during the simulation. There are many more examples of sugar repuckering in the AT decamers, and the relative frequency of such repuckering is qualitatively consistent with what one would expect based on molecular mechanics studies. A comparison of the torsional angles, sugar puckers, helical parameters, root mean square atom amplitudes and hydrogen bond parameters of the sequence d(CGCGA)·d(TCGCG) with the two mismatched analogues demonstrates that the effect of the poorer hydrogen bonding at the central base pair is transmitted throughout the sequence, leading to significantly greater root mean square fluctuations in all dihedral angles, significantly higher % of non‐“standard C2′ endo” sugar puckers, generally longer H‐bond distances, with greater % of “long” H bonds during the simulation, larger RMS amplitude of atomic fluctuations and greater helix twist and tilt of the base pairs. The average helix repeat is 9.0 for the AC mismatch, and 10.1 for the GA mismatch, compared to 10.0 for the normal sequence.