Ratio Of Relative Change Research Articles

Investigation of kinetic-order sensitivities in metabolic reaction networks

Kinetic-order sensitivity (the ratio of relative change in a dependent variable to the relative change in a kinetic order in a power-law–type differential equation) has recently become an important indicator in metabolic pathway analysis using mathematical models with parameter values determined from time-series data on cellular metabolite concentrations. Here, we discuss a potential problem in calculating kinetic-order sensitivities. When the steady-state metabolite concentration is less than unity, a slight increase in the kinetic order changes the metabolite concentration in the incorrect direction, yielding a kinetic-order sensitivity value with an incorrect sign. This is caused by a property of the power-law function (y=Xn): when X is less than unity, y decreases for a larger positive n or for a smaller absolute value of negative n. We propose two solutions. The first is to directly calculate the kinetic-order sensitivities and then reverse the sign of the relevant value if a steady-state metabolite concentration less than unity is involved. The second involves calculation of the kinetic-order sensitivities after setting all metabolite concentrations to values greater than unity (e.g., by changing the units from mM to μM). The latter method changes the absolute values of the kinetic-order sensitivities according to the magnitude of a multiplication factor, because kinetic-order sensitivities do not have unique values. Nevertheless, since the normalized absolute values exhibit an almost identical distribution, it should not be difficult to identify which kinetic order has greater effect, although kinetic order rankings may change slightly under different calculation conditions.

Numerical investigations on Re-independence for the turbulent flow and pollutant dispersion under the urban boundary layer with some experimental validations

This paper numerically studied the Re-independence of turbulent flow and pollutant dispersion around five scaled building models. The RANS-based CFD model, hereafter called numerical wind tunnel (NWT) model, was validated by wind-tunnel experiments and applied to investigate the flow-structure independence on building Reynolds number (ReH) and roughness Reynolds number (Rer). The ratio of relative change (RRC) was used to evaluate the Re-independence with 5% selected as the threshold. The results show that the critical ReH (ReH,crit) is strongly affected by the building structure, particularly the building height. However, the value of the critical Rer (Rer,crit) in the pedestrian level plane changes very little with the different building models, which is suggested to be 25 in terms of the RRC criterion. Distributions of dimensionless velocity and concentration in the pedestrian level planes validated this suggested value. For the RANS turbulence models tested in this paper (high Reynolds number model and low Reynolds number model) the predicted value of Rer,crit is independent on the model. This work improves the understanding of Re-independence in the investigation of the flow and pollutant dispersion by using wind-tunnel experiment.

이상자료가 연안 환경자료의 통계 척도에 미치는 영향

The statistical measures of the coastal environmental data are used in a variety of statistical inferences, hypothesis tests, and data-driven modeling. If the measures are biased, then the statistical estimations and models may also be biased and this potential for bias is great when data contain some outliers defined as extraordinary large or small data values. This study aims to suggest more robust statistical measures as alternatives to more commonly used measures and to assess the performance these robust measures through a quantitative evaluation of more typical measures, such as in terms of locations, spreads, and shapes, with regard to environmental monitoring data in the Busan coastal sea. The detection of outliers within the data was carried out on the basis of Rosner’s test. About 5−10% of the nutrient data were found to contain outliers based on Rosner’s test. After removal (zero-weighting) of the outliers in the data sets, the relative change ratios of the mean and standard deviation between before and after outlier-removal conditions revealed the figures 13 and 33%, respectively. The variation magnitudes of skewness and kurtosis are 1.36 and 8.11 in a decreasing trend, respectively. On the other hand, the change ratios for more robust measures regarding the mean and standard deviation are 3.7−10.5%, and the variation magnitudes of robust skewness and kurtosis are about only 2−4% of the magnitude of the non-robust measures. The robust measures can be regarded as outlier-resistant statistical measures based on the relatively small changes in the scenarios before and after outlier removal conditions.

Different Growth Promoting Effects of Endophytic Bacteria on Invasive and Native Clonal Plants.

The role of the interactions between endophytes and alien plants has been unclear yet in plant invasion. We used a completely germ-free culture system to quantify the plant growth-promoting (PGP) effects of endophytic bacteria Bacillus sp. on aseptic seedlings of Wedelia trilobata and of its native clonal congener W. chinensis. The endophytic bacteria did not affect the growth of W. chinensis, but they significantly promoted the growth of W. trilobata. With the PGP effects of endophytic bacteria, relative change ratios of the clonal traits and the ramets’ growth traits of W. trilobata were significantly greater than those of W. chinensis. Our results indicate that the growth-promoting effects of endophytes may differ between invasive and native clonal plants, and the endophytes of invasive plant may be host-specific to facilitate plant invasion.

Effects of long-range aerosol transport on the microphysical properties of low-level liquid clouds in the Arctic

Abstract. The properties of low-level liquid clouds in the Arctic can be altered by long-range pollution transport to the region. Satellite, tracer transport model, and meteorological data sets are used here to determine a net aerosol–cloud interaction (ACInet) parameter that expresses the ratio of relative changes in cloud microphysical properties to relative variations in pollution concentrations while accounting for dry or wet scavenging of aerosols en route to the Arctic. For a period between 2008 and 2010, ACInet is calculated as a function of the cloud liquid water path, temperature, altitude, specific humidity, and lower tropospheric stability. For all data, ACInet averages 0.12 ± 0.02 for cloud-droplet effective radius and 0.16 ± 0.02 for cloud optical depth. It increases with specific humidity and lower tropospheric stability and is highest when pollution concentrations are low. Carefully controlling for meteorological conditions we find that the liquid water path of arctic clouds does not respond strongly to aerosols within pollution plumes. Or, not stratifying the data according to meteorological state can lead to artificially exaggerated calculations of the magnitude of the impacts of pollution on arctic clouds.

Application of ECT and relative change ratio of capacitances in probing anomalous objects in water

Nowadays electrical capacitance tomography (ECT) is mainly adopted for detecting dielectrics of low permittivity in chemical and petroleum industries. In these fields, to meet the demand of measuring capacitances within the range of low values, ECT still needs relatively high requirements of designing its system. In this work, an ECT system is simplified to probe anomalous objects in water with high permittivity. Additionally, the relative change ratio (RCR) of capacitances is presented for image reconstruction in terms of the high permittivity background. RCR is the change value of a capacitance divided by its background value. To verify the effectiveness of the simplification of an ECT system and the method of RCR for image reconstruction, simulations and experiments associated with media of high permittivity (i.e. water) were conducted. The obtained results demonstrate that the simplified ECT system based on RCRs of simulated and measured capacitances is capable of effectively probing anomalous objects in tap-water and sodium chloride solutions with different concentrations. Therefore the RCR is recommended when the sensing domain of ECT is of the high permittivity background. Besides the simplification of ECT systems can be appealing and beneficial to introduced ECT into other fields associated with water flows, such as hydrology, hydrogeology, hydroponics, environment science, etc.

The potentials of using selection index in the assessment of breeding values of Holstein breeds in Serbia

The conducted research was aimed at constructing equations of selection index that would be used in the selection of the Holstein-Friesian breed animals in Serbia. The construction of the selection index includes the most important milk traits observed in standard lactation: milk yield (MY305), milk fat content (% MF305) and protein content (% MP305). The variance and covariance necessary for the construction of selection index are calculated using the mixed model by the method of least squares. The economic value of traits is expressed as a ratio of relative changes in costs per unit of traits included in the selection index. Livestock included in the research produced, in the first standard lactation, an average of 7681 kg of milk with 3.58% milk fat and 3.28% protein. The equation of the selection index presented in the paper is selected from the group of equations of selection index, as an equation with the highest correlation between the equation and the aggregate genotype, which amounted to 0.2156.

Performance Evaluation of Heat Transfer Enhancement in Plate-fin Heat Exchangers with Offset Strip Fins

Generally, the Offset Strip Fin (OSF) in a plate-fin heat exchanger provides a greater heat transfer coefficient than plain plate-fin, but it also leads to an increase in flow friction. A new parameter, called relative entropy generation distribution factor, Ψ*, is proposed to evaluate the thermodynamic advantages of OSFs. This parameter presents a ratio of relative changes of entropy generation. The relative effects of the geometrical parameters α, γ and δ are discussed. The results show that there exist the optimum values of α and γ at a certain flow condition, which obviously maximize the degree of the heat transfer enhancement of OSFs.

Work schedules and 11-year progression of carotid atherosclerosis in middle-aged Finnish men.

This study investigated the relationship between different work schedules and progression of carotid atherosclerosis, an early indicator of cardiovascular disease (CVD). We studied 621 men, aged 42-60 years, in the prospective Kuopio Ischemic Heart Disease Risk Factor Study cohort. Using multivariable regressions adjusting for 22 covariates including total time worked during follow-up, we evaluated the associations of baseline work schedules with 11-year progression of ultrasonographically assessed carotid intima-media thickness (IMT), and their variation by preexisting CVD. Standard daytime work, weekend shifts, and evening/night/rotating shifts were associated with 31%, 37%, and 33% increases in IMT, respectively. Compared to daytime workers, weekend workers experienced a faster progression of carotid atherosclerosis [relative change ratio (RCR) = 1.05, 95% CI: 1.00-1.09)]. This ratio was higher among men who had preexisting CVD. Weekend shifts, more than standard daytime work, appear to accelerate carotid atherosclerosis progression among middle-aged Finnish men, especially those with pre-existing CVD.

Investigation of Re -independence of turbulent flow and pollutant dispersion in urban street canyon using numerical wind tunnel (NWT) models

Abstract This paper numerically and experimentally studied the Reynolds number independence (Re-independence) of turbulent flow and pollutant dispersion in urban areas. The concept of numerical wind tunnel (NWT) is proposed and validated by prototype wind-tunnel experimental measurements. A new physical quantity: the ratio of relative change, RRC, is proposed to investigate the Re-independence quantitatively. For the given street canyon, numerically predicted variations of RRC vs. building Reynolds number (ReH) from three k–ɛ turbulence models agree well with each other, and the variation trend shows that there exist two flow regimes in the range of ReH studied: flow in low ReH region is strongly affected by ReH, while that in higher ReH region is weakly affected by ReH, giving a strong support to the concept of Re-independence of turbulent flow. A criterion of RRC less than 5% is suggested to determine the value of the critical Reynolds number. For the street canyon studied, such determined critical building Reynolds number (ReH,crit) is 3.3 × 104. Examinations of dimensionless velocity contours, local velocity vectors, and concentration contours demonstrate the feasibility of the suggested critical Reynolds number.

Economics of Recommendations Systems: The Role of Customer Responsiveness to Prices and Quality

To our knowledge, recommendation systems in the current literature do not account for preferences in terms of responsiveness to prices and quality. The major goal of this project is to fill this gap in the literature by employing the economic concept of elasticity with respect to prices and quality. Elasticity of demand with respect to any variable (price, income, quality, etc.) is the ratio of relative changes in quantity to those in the variable in question. Collaborative and content-based filtering methods as well as their hybrid systems take into account various characteristics of past purchases, but we will attempt to venture a step ahead: incorporate the behavior of the customer ‘at margin’, i.e., compute the degree of responsiveness to changes in prices and ratings. The algorithm involves two stages: some recommendations are short-listed using existing methods in the first stage and they are further fine-tuned using elasticity in the second stage, into “buy” and “not buy” categories. We also predict the percentage changes in purchases of items, in response to changes in prices and quality. We illustrate the usefulness of this methodology using a movie ratings dataset.

Gene regulatory network inference and validation using relative change ratio analysis and time-delayed dynamic Bayesian network.

The Dialogue for Reverse Engineering Assessments and Methods (DREAM) project was initiated in 2006 as a community-wide effort for the development of network inference challenges for rigorous assessment of reverse engineering methods for biological networks. We participated in the in silico network inference challenge of DREAM3 in 2008. Here we report the details of our approach and its performance on the synthetic challenge datasets. In our methodology, we first developed a model called relative change ratio (RCR), which took advantage of the heterozygous knockdown data and null-mutant knockout data provided by the challenge, in order to identify the potential regulators for the genes. With this information, a time-delayed dynamic Bayesian network (TDBN) approach was then used to infer gene regulatory networks from time series trajectory datasets. Our approach considerably reduced the searching space of TDBN; hence, it gained a much higher efficiency and accuracy. The networks predicted using our approach were evaluated comparatively along with 29 other submissions by two metrics (area under the ROC curve and area under the precision-recall curve). The overall performance of our approach ranked the second among all participating teams.Electronic supplementary materialThe online version of this article (doi:10.1186/s13637-014-0012-3) contains supplementary material, which is available to authorized users.

A local damage detection approach based on restoring force method

Chain-like systems have been studied by many researchers for their simple structure and wide range of application. Previously, the damage in a chain-like system was detected by the reduction of the mass-normalized stiffness coefficient for certain elements as reported by Nayeri et al. (2008 [16]). However, some shortcomings exist in that approach and for overcoming them; an improved approach is derived and presented in this paper. In our improved approach, the mass normalized stiffness coefficients under two states (baseline state and potentially damaged state) are first estimated by a least square method, then these mass-stiffness coupled coefficients are decoupled to derive stiffness and mass relative change ratios for individual elements. These ratios are assembled in a vector, which is defined as damage indication vector (DIV). Each component in DIV is normalized individually to one to get multiple solutions. These solutions are averaged for estimating relative system changes, while abnormal solutions are discarded. The work of judging a solution as normal or abnormal is done by a cluster analysis algorithm. The most intriguing merit of this improved approach is that the relative stiffness and mass changes, which are coupled in the previous approach, can be separately identified. By this approach, the damage (single or multiple) extent and location can be correctly detected under operational conditions, meanwhile the proposed damage index has a clear physical meaning and is directly related to the stiffness reduction of corresponding structural elements. For illustrating the effectiveness and robustness of the improved approach, numerical simulation of a four floor building was carried out and experimental data from a structure tested at the Los Alamos National Laboratory was employed. Identified structural changes with both simulation and experimental data properly indicated the location and extent of actual structural damage, which validated the proposed approach.

Seasonal carbohydrate dynamics and growth in Douglas-fir trees experiencing chronic, fungal-mediated reduction in functional leaf area

Stored non-structural carbohydrates (NSCs) could play an important role in tree survival in the face of a changing climate and associated stress-related mortality. We explored the effects of the stomata-blocking and defoliating fungal disease called Swiss needle cast on Douglas-fir carbohydrate reserves and growth to evaluate the extent to which NSCs can be mobilized under natural conditions of low water stress and restricted carbon supply in relation to potential demands for growth. We analyzed the concentrations of starch, sucrose, glucose and fructose in foliage, twig wood and trunk sapwood of 15 co-occurring Douglas-fir trees expressing a gradient of Swiss needle cast symptom severity quantified as previous-year functional foliage mass. Growth (mean basal area increment, BAI) decreased by ∼80% and trunk NSC concentration decreased by 60% with decreasing functional foliage mass. The ratio of relative changes in NSC concentration and BAI, an index of the relative priority of storage versus growth, more than doubled with increasing disease severity. In contrast, twig and foliage NSC concentrations remained nearly constant with decreasing functional foliage mass. These results suggest that under disease-induced reductions in carbon supply, Douglas-fir trees retain NSCs (either actively or due to sequestration) at the expense of trunk radial growth. The crown retains the highest concentrations of NSC, presumably to maintain foliage growth and shoot extension in the spring, partially compensating for rapid foliage loss in the summer and fall.

Optimal design of spiral electromagnetic sensor for phase holdup measurement

Electromagnetic sensors can obtain the distributions of the medium through excitation and sensing coils distributed on the boundary. In this paper, a novel spiral electromagnetic sensor was proposed for phase holdup measurement. The sensitivity matrices of the spiral sensors of 180 and 360 degrees rotation were derived based on field theory and the design was optimized based on sensitivity analysis. The trends and rules for selecting the optimum parameters were obtained. The optimized spiral electromagnetic sensors have better and more homogenous sensitivity distributions. The experiment showed that the electric signals obtained were good indicators of the phase holdup. The correlation curves between phase holdup and the relative change ratio of the phase angle of spiral sensors were obtained which proved the feasibility and accuracy of the phase holdup measurement by the spiral electromagnetic sensors.

Determination of Poisson Ratio of Bovine Extraocular Muscle by Computed X-Ray Tomography

The Poisson ratio (PR) is a fundamental mechanical parameter that approximates the ratio of relative change in cross sectional area to tensile elongation. However, the PR of extraocular muscle (EOM) is almost never measured because of experimental constraints. The problem was overcome by determining changes in EOM dimensions using computed X-ray tomography (CT) at microscopic resolution during tensile elongation to determine transverse strain indicated by the change in cross-section. Fresh bovine EOM specimens were prepared. Specimens were clamped in a tensile fixture within a CT scanner (SkyScan, Belgium) with temperature and humidity control and stretched up to 35% of initial length. Sets of 500–800 contiguous CT images were obtained at 10-micron resolution before and after tensile loading. Digital 3D models were then built and discretized into 6–8-micron-thick elements. Changes in longitudinal thickness of each microscopic element were determined to calculate strain. Green's theorem was used to calculate areal strain in transverse directions orthogonal to the stretching direction. The mean PR from discretized 3D models for every microscopic element in 14 EOM specimens averaged 0.457 ± 0.004 (SD). The measured PR of bovine EOM is thus near the limit of incompressibility.

Effects of Transitory Stimulation Interval Exercise on Physical Function: A Randomized Controlled Pilot Study among Japanese Subjects

Interval training is effective for promoting aerobic capacity and general health. However, it involves repeated high-intensity activity, which could pose cardiovascular risks for the elderly or people who are less fit. We developed a transitory stimulation interval exercise (TSIE) in which the duration of strenuous exertion was reduced to 30 seconds at 75% VO2max of intensity. This pilot study aims to explore the effects of this mode of exercise. Thirty women were randomized and stratified into the TSIE group, the continuous moderate exercise (CME) group, or the no-exercise (NE) group. The two exercise groups performed exercises for 12 weeks. Significant positive changes were observed in the TSIE group compared with the NE group in the relative change ratio from baseline in body weight and VO2max, but no significant differences were observed between the CME group and the NE group. Glycated hemoglobin A1c (HbA1c) decreased significantly in both exercise groups compared with the NE group. Overall, there were few significant differences between the CME group and the TSIE group. There might not be any differences between the TSIE and the CME in a long term intervention with equalized training volumes.

Efficacy and safety of initial combination therapy with linagliptin and pioglitazone in patients with inadequately controlled type 2 diabetes: a randomized, double-blind, placebo-controlled study

To compare the efficacy, safety and tolerability of linagliptin or placebo administered for 24 weeks in combination with pioglitazone in patients with type 2 diabetes mellitus (T2DM) exhibiting insufficient glycaemic control (HbA1c 7.5-11.0%). Patients were randomized to receive the initial combination of 30 mg pioglitazone plus 5 mg linagliptin (n = 259) or pioglitazone plus placebo (n = 130), all once daily. The primary endpoint was change from baseline in HbA1c after 24 weeks of treatment, adjusted for baseline HbA1c and prior antidiabetes medication. After 24 weeks of treatment, the adjusted mean change (±s.e.) in HbA1c with the initial combination of linagliptin plus pioglitazone was -1.06% (±0.06), compared with -0.56% (±0.09) for placebo plus pioglitazone. The difference in adjusted mean HbA1c in the linagliptin group compared with placebo was -0.51% (95% confidence interval [CI] -0.71, -0.30; p < 0.0001). Reductions in fasting plasma glucose (FPG) were significantly greater for linagliptin plus pioglitazone than with placebo plus pioglitazone; -1.8 and -1.0 mmol/l, respectively, equating to a treatment difference of -0.8 mmol/l (95% CI -1.2, -0.4; p < 0.0001). Patients taking linagliptin plus pioglitazone, compared with those receiving placebo plus pioglitazone, were more likely to achieve HbA1c of <7.0% (42.9 vs. 30.5%, respectively; p = 0.0051) and reduction in HbA1c of ≥0.5% (75.0 vs. 50.8%, respectively; p < 0.0001). β-cell function, exemplified by the ratio of relative change in adjusted mean HOMA-IR and disposition index, improved. The proportion of patients that experienced at least one adverse event was similar for both groups. Hypoglycaemic episodes (all mild) occurred in 1.2% of the linagliptin plus pioglitazone patients and none in the placebo plus pioglitazone group. Initial combination therapy with linagliptin plus pioglitazone was well tolerated and produced significant and clinically meaningful improvements in glycaemic control. This combination may offer a valuable additive initial treatment option for T2DM, particularly where metformin either is not well tolerated or is contraindicated, such as in patients with renal impairment.

A Qualitative and Quantitative Proteomic Study of Human Microdialysate and the Cutaneous Response to Injury

The extracellular fluid space is the site of intercellular communication and represents an important source of mediators that can shed light on the parenchymal environment. Sampling of this compartment using continuous microdialysis allows assessment of the temporal changes in extracellular mediators involved in tissue homeostasis and disease processes. However, novel biomarker identification is limited by the current need to utilize specific, targeted molecular assays. The aim of our study was to explore the use of qualitative and quantitative proteomic approaches to define the protein content of dermal dialysate. Timed dermal dialysate samples were collected from healthy human volunteers for 5 h following probe insertion, using a 3,000-kDa MWCO membrane perfused at a rate of 3 μl/min. Dialysate proteins were identified using GeLC-MS/MS and iTRAQ approaches and functions assigned according to the Gene Ontology classification system. More than 80 proteins (size range 11-516 kDa) originating from both extracellular and intracellular fluid space were identified using the qualitative approach of GeLC-MS/MS. Quantitative iTRAQ data were obtained for 27 proteins with relative change ratios between consecutive timed samples showing changes of >1.5-fold. Interstitial proteins can be identified and measured using shotgun proteomic techniques and changes detected during the acute inflammatory response. Our findings provide a platform from which to explore novel protein biomarkers and their modulation in health and disease.

Parameter Estimation of Conditional Random Fields Model By Improved Particle Swarm Optimizer

A new parameter estimation algorithm based on improved particle swarm optimizer is proposed to improve the precision and recall rate of conditional random fields model. Aggregation degree of particle swarm is utilized to control particle swarm optimizer’s early local convergence, the relative change ratio of log-likelihood between iterations is employed to end its iterations, and the inertia factor and learning factor are set as linear variables to control the searching scope. We evaluate our method on GENIA, GENETAG and private library. The experiment results prove our method outperforms traditional parameter estimation method on precision and recall.