Partial Rank Correlation Analysis Research Articles

Association of multi-phase rates of force development during an isometric leg press with vertical jump performances.

This study aimed to elucidate characteristics of explosive force-production capabilities represented by multi-phase rate of force developments (IRFDs) during isometric single-leg press (ISLP) through investigating relationships with countermovement (CMJ) and rebound continuous jump (RJ) performances. Two-hundred-and-thirty male athletes performed ISLP, CMJ with an arm swing (CMJAS), and RJ with an arm swing (RJAS). IRFDs were measured during ISLP using a custom-built dynamometer, while CMJAS and RJAS were measured on force platforms. The IRFDs were obtained as rates of increase in force across 50 ms in the interval from the onset to 250 ms. Jump height (JH) was obtained from CMJAS, while RJAS provided JH, contact time (CT), and reactive strength index (RSI) values. All IRFDs were correlated with CMJAS-JH (ρ = 0.20-0.45, p ≤ 0.003), RJAS-JH (ρ = 0.22-0.46, p ≤ 0.001), RJAS-RSI (ρ = 0.29-0.48, p < 0.001) and RJAS-CT (ρ = -0.29 to -0.25, p ≤ 0.025). When an influence of peak force was considered using partial rank correlation analysis, IRFDs during onset to 150 ms were correlated with CMJAS-JH (ρxy/z = 0.19-0.36, p ≤ 0.004), IRFDs during onset to 100 ms were correlated with RJAS-JH and RJAS-RSI (ρxy/z = 0.33-0.36, p < 0.001), and IRFD during onset to 50 ms was only correlated with RJAS-CT (ρxy/z = -0.23, p < 0.001). The early phase (onset to 150 ms) IRFDs measured using ISLP enabled the assessment of multiple aspects of leg-extension strength characteristics that differ from maximal strength; these insights might be useful in the assessment of the athletes' leg-extension strength capabilities.

Maternal body mass index, birthweight, and placental glucose metabolism: evidence for a role of placental hexokinase

BackgroundThe principal fetal energy source is glucose provided by placental transfer of maternal glucose. However, the placenta’s glucose consumption exhibits considerable variation. Hexokinase is the first and one of the rate-limiting enzymes of glycolysis that phosphorylates glucose to glucose 6-phosphate. The role of placental hexokinase activity in human placental glucose metabolism is unknown. ObjectivesTo test the hypothesis that placental hexokinase activity is related to maternal body mass index, placental glucose uptake and consumption, and birth weight. Study designSixty-seven healthy pregnant participants at term were included in this study at Oslo University Hospital, Norway. Placental hexokinase activity was measured by using a colorimetric assay. The mass of glucose taken up by the uteroplacental unit and the fetus was obtained by measuring arterio-venous glucose differences combined with Doppler assessment of uterine and umbilical blood flow. Blood samples were obtained from the maternal radial artery, uterine vein, and umbilical artery and vein. The uteroplacental glucose consumption constituted the difference between uteroplacental and fetal glucose uptake. Spearman’s rank correlation was performed for statistical analyses to study the correlation of placental hexokinase activity (mU/mg protein) with prepregnancy body mass index, maternal glucose and insulin, birth weight, uteroplacental glucose uptake and consumption, and fetal glucose uptake (μmol/min). Partial rank correlation analysis was performed when controlling for hours of fasting or placental weight. ResultsHexokinase activity was detectable in all placental tissue samples. Mean (SD) activity was 19.6 (4.64) mU/mg of protein. Placental hexokinase activity correlated positively with prepregnancy body mass index (Spearman’s rho (ρ)=0.33; P=0.006). Upon controlling for hours of fasting, hexokinase activity showed positive correlations with both maternal glucose (r=0.30; P=0.01) and insulin (r=0.28; P=0.02). Hexokinase activity was positively correlated with uteroplacental glucose uptake (ρ=0.31; P=0.01) and consumption (ρ=0.28; P=0.02). Hexokinase activity did not correlate with fetal glucose uptake. Upon controlling for placental weight, hexokinase activity showed a positive correlation with birth weight (r=0.31; P=0.01). ConclusionOur findings suggest that placental hexokinase, being crucial for uteroplacental retention of glucose for own disposition, is related to both maternal body mass index and birth weight independent of placental weight. Placental hexokinase may play a central role in the relationship between maternal glucose dysregulation and fetal growth. Thus, the current study supports the need to develop clinically useful tools to assess the metabolic properties of the placenta.

Global analysis of tuberculosis dynamical model and optimal control strategies based on case data in the United States

Tuberculosis is a chronic infectious disease with a high death rate, which has attracted worldwide attention. In this paper, we focus on the annual data of tuberculosis in the United States from 1988 to 2019. Firstly, we propose an SVEITR dynamical model with vaccination, fast and slow progression, incomplete treatment, and relapse. Mathematical analyses show that the disease-free equilibrium is globally asymptotically stable (unstable) if R0≤1 (if R0>1). There exists a unique endemic equilibrium that is globally asymptotically stable when R0>1. Next, we use the Markov-chain Monte-Carlo (MCMC) method to acquire the model’s optimal parameters. From R0=1.3763, tuberculosis will not be eliminated without control measures taken in the United States. Through partial rank correlation analysis, the most sensitive parameters to the basic reproduction number are found. Based on this, we take the actual epidemic situation of tuberculosis in the United States into considerations to get the required conditions for optimal control using Pontryagin’s maximum principle and cost-effectiveness analysis. Implementation of three public health measures: tuberculosis prevention and control education, timely treatment, and enhanced efficacy can reduce the prevalence of tuberculosis in the United States. But at present, it is challenging for us to achieve the goal of eliminating tuberculosis by 2030 as called for by WHO.

Correlations among Tree Quality, Stand Characteristics, and Site Characteristics in Plantation Teak in Mountainous Areas of Lao PDR

Teak (Tectona grandis Linn. f) is a globally valuable hardwood tree species whose growth performance and tree quality characteristics are controlled by various factors. Teak tree quality characteristics such as stem straightness, buttressing, and protuberant buds/knots are important in the sawing process, and directly affect timber yield, timber grade, recovery, and cost. In this study, we assessed the relationships among tree quality characteristics, stand characteristics, and site characteristics in plantation teak in the Luang Prabang province of the Lao PDR. We established 53 sample plots (20 × 20 m) and measured a total of 2149 sample trees. The stand-level tree age ranged from 10 to 31 years, and the trees were distributed in various modes of topography. The altitude ranged from 287 to 867 masl. The results of Spearman’s partial rank correlation analysis among the parameters revealed the present condition of the teak plantation forest in the region. The altitude was related to stand age and was correlated with tree quality characteristics such as epicormic shoots, mode of branching, and branch size. The correlation results suggest that higher-density plantation at the higher altitude sites might be suitable for teak plantations in this area. In addition, we found that a longer rotation in forest management might degrade tree quality.

Correlation of the modified Medical Research Council dyspnea scale with airway structure assessed by three-dimensional CT in patients with chronic obstructive pulmonary disease.

Dyspnea is a common symptom in chronic obstructive pulmonary disease (COPD). The modified Medical Research Council (mMRC) dyspnea scale is a widely used questionnaire to assess dyspnea. However, the relationship of the mMRC dyspnea scale with morphological airway structures in COPD remains unclear. We evaluated the correlation between the mMRC dyspnea scale and imaging-based airway structures in patients with COPD. The wall area (WA) and airway inner luminal area (Ai) of third-to sixth-generation bronchi and the percentage of low attenuation area with less than -950 HU (%LAA) of the lungs were measured using three-dimensional computed tomography in patients with COPD. WA and Ai were corrected by body surface area (BSA). Forty-two clinically stable patients with COPD were enrolled. The median (range) mMRC dyspnea scale was 2 (0-3). The mMRC dyspnea scale score was significantly correlated with WA/BSA of fifth- and sixth-generation bronchi (Spearman correlation coefficient ρ = 0.386, p = 0.012; ρ = 0.484, p = 0.001, respectively). Partial rank correlation analysis showed that the mMRC dyspnea scale score was significantly correlated with WA/BSA of sixth-generation bronchi, independent of the confounding factors of age, body mass index, %predicted forced expiratory volume in 1 s, %LAA, and Ai/BSA (ρ = 0.481, p = 0.003). However, the %LAA and Ai/BSA were not correlated with this dyspnea scale. Bronchial WA assessed by three-dimensional computed tomography may be used as an assessment tool for dyspnea in patients with COPD.

Relationship between fraction of exhaled nitric oxide and airway morphology assessed by three-dimensional CT analysis in asthma

Fraction of exhaled nitric oxide (FeNO) provides information about chronic inflammation in asthma. However, its relationship with structural changes in the airways is unknown. We aimed to evaluate the correlation between computer-based airway changes and FeNO in patients with asthma. The wall area (WA) and airway inner luminal area (Ai) of the third- to sixth-generation bronchi were measured using three-dimensional computed tomography in asthmatic patients. Each value was corrected by body surface area (BSA). Relationships between FeNO and WA/BSA and Ai/BSA were evaluated. Forty-one clinically stable patients with asthma were evaluated. FeNO was significantly correlated with WA/BSA of the third-, fourth-, fifth- and sixth-generation bronchi (Spearman correlation coefficient (ρ) = 0.326, p = 0.041; ρ = 0.356, p = 0.025; ρ = 0.496, p = 0.002; and ρ = 0.529, p < 0.001, respectively). The correlation with sixth-generation bronchi was significantly greater than with the third-generation bronchi (p = 0.047). Partial rank correlation analysis indicated FeNO was significantly correlated with WA/BSA of the sixth-generation bronchi, independent from confounding factors of Ai/BSA, age, duration of asthma, dose of inhaled corticosteroid, blood eosinophil percentage, and blood IgE (ρ = 0.360, p = 0.034). In contrast, there was no correlation between FeNO and Ai/BSA. FeNO correlates with bronchial wall thickening in asthma patients. Measurement of FeNO may be useful to detect airway remodeling in asthma.

Towards an Improved Environmental Understanding of Land Surface Dynamics in Ukraine Based on Multi-Source Remote Sensing Time-Series Datasets from 1982 to 2013

Ukraine has experienced immense environmental and institutional changes during the last three decades. We have conducted this study to analyze important land surface dynamics and to assess processes underlying the changes. This research was conducted in two consecutive steps. To analyze monotonic changes we first applied a Mann–Kendall trend analysis of the Normalized Difference Vegetation Index (NDVI3g) time series. Gradual and abrupt changes were studied by fitting a seasonal trend model and detecting the breakpoints. Secondly, essential environmental factors were used to quantify their possible relationships with land surface changes. These factors included soil moisture as well as gridded air temperature and precipitation data. This was done using partial rank correlation analysis based on annually aggregated time-series. Our results demonstrate that positive NDVI trends characterize approximately one-third of Ukraine’s land surface, located in the northern and western areas of the country. Negative trends occurred less frequently, covering less than 2% of the area and are distributed irregularly across the country. Monotonic trends were rarely found; shifting trends were identified with a greater frequency. Trend shifts were seen to occur with an increased frequency following the period of the 2000s. We determined that land surface dynamics and climate variability are functionally interdependent; however, the relative influence of the drivers varies in different locations. Among the factors analyzed, the air temperature variable explains the largest portion of NDVI variability. High air temperature/NDVI correlation coefficients (r = 0.36 − 0.77) are observed over the entire country. The soil moisture content is of significant influence in the eastern portion of Ukraine (r = 0.68); precipitation (r = 0.65) was most influential in the central regions of the country. These results increase our understanding of ecosystem responses to climatic changes and anthropogenic activities.

Error decomposition of nine passive and active microwave satellite soil moisture data sets over Australia

Abstract Soil moisture is one of the essential climate variables for the Global Climate Observing System (GCOS) that has been prioritized by the ESA's Climate Change Initiative to construct its homogeneous long-term climate record. This requires a consistent characterization of the error structures in the individual data sets, which vary due to changes in instrument configuration and calibration, and retrieval algorithm design. In this paper, the random error and systematic differences in nine passive and active microwave satellite soil moisture products over Australia (time coverage: 1978–present) are estimated in a same manner for SM components at subseasonal and seasonal-to-interannual timescales separately. The multi-scale error structures are found to be non-trivial and vary between the products, giving cause for conducting multi-scale merging with awareness of these differences. Noticeable similarities between the error structures of the satellite products derived from same retrieval algorithm and same measuring frequency however suggest transferability of error parameters between them. Using partial rank correlation analysis, the error maps are linked to statistics on vegetation index, digital elevation, soil moisture and soil temperature, and land cover fractions and mixing in order to explain the observed variability and the similarities between the products.

Connecting Local and Global Sensitivities in a Mathematical Model for Wound Healing.

The process of wound healing is governed by complex interactions between proteins and the extracellular matrix, involving a range of signaling pathways. This study aimed to formulate, quantify, and analyze a mathematical model describing interactions among matrix metalloproteinases (MMP-1), their inhibitors (TIMP-1), and extracellular matrix in the healing of a diabetic foot ulcer. De-identified patient data for modeling were taken from Muller et al. (Diabet Med 25(4):419-426, 2008), a research outcome that collected average physiological data for two patient subgroups: "good healers" and "poor healers," where classification was based on rate of ulcer healing. Model parameters for the two patient subgroups were estimated using least squares. The model and parameter values were analyzed by conducting a steady-state analysis and both global and local sensitivity analyses. The global sensitivity analysis was performed using Latin hypercube sampling and partial rank correlation analysis, while local analysis was conducted through a classical sensitivity analysis followed by an SVD-QR subset selection. We developed a "local-to-global" analysis to compare the results of the sensitivity analyses. Our results show that the sensitivities of certain parameters are highly dependent on the size of the parameter space, suggesting that identifying physiological bounds may be critical in defining the sensitivities.

Monte Carlo analysis of parameter uncertainty in matrix models for the weed Cirsium vulgare

Summary Parameter uncertainty challenges the use of matrix models because it violates key assumptions underlying elasticity analyses. We have developed a matrix model to compare Monte Carlo methods with elasticity analyses for estimation of the relative importance of factors in the asymptotic population growth rate, λ, of Cirsium vulgare (spear thistle) in Nebraska, USA. We calculated λ for a base model using 11 parameter estimates available for Nebraska populations plus eight extracted from the literature, causing parameter uncertainty. We then calculated λ for 10 000 alternative models using Monte Carlo parameter estimation; parameters were drawn from the full range of each parameter in the literature and partial rank correlation analysis (PRCC) was used to order the parameters by the magnitude of their effect on λ. Monte Carlo analysis found that insect floral herbivory, affecting the regeneration transition, was the most important parameter affecting λ, whereas elasticity analyses suggested that the transition from small to medium size was the most significant. Statistical comparison, using PRCC vs. lower level elasticity (LLE), showed that the Monte Carlo analysis provided a more accurate assessment. As λ &gt; 1 in 99% of the model runs even with significant floral herbivory, we added two parameters influenced by weed management (probability of large thistles dying without producing seed and proportion of seeds that failed to germinate). Simulations that included reductions in these parameters, along with floral herbivory, led to λ &lt; 1 in 17% of the runs, suggesting these three factors interact to produce the low densities observed for this invasive thistle in our study area. Synthesis and applications. This study demonstrates the utility of the Monte Carlo approach for modelling weed dynamics with parameter uncertainty and multiple, potentially interacting, parameters. Invasive population growth by C. vulgare could be limited by a combination of weed management practices and the biotic resistance imposed by native floral herbivores.

The role of silent intervals for sentence intelligibility in fluctuating noise in hearing-impaired listeners

Fluctuating interfering noises are highly suitable for speech audiometry because of the large inter-individual variability in intelligibility results. This study explores the maximum duration of silent intervals in the masker as an important factor underlying sentence intelligibility in fluctuating noise. Three versions of speech-simulating fluctuating interfering noises based on the icra noises (Dreschler et al, ) were explored: The original noise which simulates one interfering speaker and contains pause durations up to two seconds, as well as two modified versions with pause durations limited to 250 ms and 62.5 ms, respectively. In addition, a stationary speech-shaped noise was used. Test-retest reliability as well as speech reception threshold (SRT) and speech intelligibility function slope were determined with hearing-impaired subjects. All fluctuating noises differentiated very well between subjects. Partial rank correlation analysis showed that SRTs in fluctuating noise with longest maximum pause durations mostly depended on SRTs in quiet. SRTs in fluctuating noises with smaller maximum pause durations correlated both with SRTs in quiet and in stationary noise.SumarioLos ruidos fluctuantes de interferencia son muy apropiados en logoaudiometría debido a la gran variabilidad inter-individuos en los resultados de inteligibilidad. Este estudio explora la duración máxima de intervalos de silencio en el enmascarador, como un importante factor subyacente en la inteligibilidad de frases en medio de ruido fluctuante. Se exploraron tres versiones de ruidos fluctuantes de interferencia simulando lenguaje, con base en los ruidos icra (Dreschler y col., 2001): el ruido original que simula la interferencia de un hablante y contiene pausas de hasta 2 segundos de duración, y también dos versiones modificadas con pausas de duración limitadas a 250 mseg y 62.5 mseg, respectivamente. Además, se utilizó un ruido estacionario moldeado como lenguaje. Se determinó la confiabilidad test-retest al igual que la pendiente de las funciones del SRT y la inteligibilidad del lenguaje, en sujetos hipoacúsicos. Todos los ruidos fluctuantes se diferenciaron muy bien entre los sujetos. Un análisis de correlación de rango parcial mostró que los SRT en ruido fluctuante con las duraciones más prolongadas de pausa máxima, dependían del SRT en silencio. Los SRT en ruido fluctuante con duraciones menores de pausa máxima, correlacionaron tanto con los SRT en silencio como con el ruido estacionario.

Relation of sediment characteristics to trace metal concentrations: a statistical study

Twenty six geographically and hydrologically diverse sediment samples were collected from major rivers in eastern China and analyzed for sediment characteristics (grain size distribution, iron, manganese and their oxyhydroxides, aluminum, total organic carbon, surface area and surface site density) and Cd, Cu, Pb and Zn concentrations. The relation of sediment characteristics to trace metal concentrations was statistically studied by Kendall rank and partial rank correlation analysis. Although a variety of sediment characteristics showed apparent correlations with trace metal concentrations, most of them were caused by the interrelation among the characteristics themselves. The partial correlation analysis indicated that trace metal concentrations of the relatively uncontaminated sediments can be better interpreted by the sediment surface area (an integrated characteristic) and aluminum content (an indication of the local geochemical processes).

A Detailed Investigation of Radio Power Selection Effects Relevant to the Study of Classical Double Radio Sources

A sample of powerful classical double radio sources, also known as FR II sources, has been assembled to study the properties of the radio sources and their gaseous environments, as well as the redshift evolution of these properties. The possibility that the observed redshift dependences of various parameters of interest are caused by radio power selection effects is investigated here using statistical tools such as two-parameter fitting and partial rank correlation analysis. It is found that the Mach number of lobe advance, the lobe propagation velocity, and the ambient gas density of the FR II sources are unlikely to be significantly affected by radio power selection effects. Hence, the observed redshift dependences of these parameters are likely to reflect real redshift evolution. A previous study by Wellman, Daly, & Wan indicates that the powerful FR II sources in this sample lie in cluster-like gaseous environments. The fact that the ambient gas density of the FR II sources is not affected by radio power selection means that these sources can be used to probe the evolution of their environments. Specifically, the observed decrease of the ambient gas density with redshift is likely to reflect real redshift evolution rather than being caused by radio power selection effects. It is interesting to note that the current data suggest that the Mach number of lobe advance is independent of redshift, while the lobe propagation velocity increases with redshift, as summarized in the final table in this paper. Radio power selection effects are likely to be quite weak, if present at all, in the study of the nonthermal pressure inside a classical double source, and the study of the characteristic size of a source. The two-parameter fitting and partial rank correlation analysis applied to the ambient gas temperature and luminosity in directed kinetic energy of the jet yield inconclusive results, so these direct analyses do not clearly indicate whether the redshift evolution of each of these two parameters is due to radio power selection effects. However, each parameter is estimated using other parameters such as the Mach number of lobe advance, the lobe propagation velocity, and the nonthermal pressure inside the radio lobe, which do not suffer significant radio power selection effects.

Lumbar disc degeneration and atherosclerosis of the abdominal aorta.

This study analyzed the relationship of disc degeneration to atherosclerotic changes in the abdominal aorta and stenosis of the ostia of the lumbar and middle sacral arteries, 86 plain radiographs of lumbosacral spines, and the corresponding abdominal aortas were evaluated in connection with routine autopsy. Disc degeneration, advanced atherosclerotic manifestations, and stenosis of the ostia of the lumbar and middle sacral arteries all increased with age (P < 0.001). After partial rank correlation analysis, keeping the effect of age constant, there was still a statistically significant association between the grade of disc degeneration and stenosis of the ostia of the arteries supplying the disc. The association was stronger at upper lumbar levels (0.001 < P < 0.01) than at lower ones (0.01 < P < 0.05). Furthermore, with complicated lesions in the abdominal aorta, disc degeneration at all lumbar levels increased. Atherosclerosis in the abdominal aorta and especially stenosis of the ostia of segmental arteries may play a part in lumbar disc degeneration.

Female preference and sexual selection for male coloration in the guppy (Poecilia reticulata)

Experiments were designed to determine the effects of male pigmentation patterns on female choice in guppies. When presented with a series of variably-colored males, females of different genetic strain consistently exhibited similar preferences (Tables 1 and 2), preferring those males with the greatest development of both carotenoid and iridescent pigments (Table 3). A partial rank correlation analysis of pigments of males indicates positive correlations between the iridescent and carotenoid pigments and also between melanins and showiness (Table 4). Only when either the carotenoid or iridescent pigments were held constant was there any effect of the other pigments on the ranking order of males by the females. Other pigments appear to be relatively unimportant in influencing female choice of males. These results indicate that females discriminate among males on the basis of color and that females of different strains prefer the same male colors rather than those characteristics of males of their own strain. The results support those models of sexual selection that hold that sexually selected traits honestly advertise the phenotypic and genetic qualities of males; they do not support models of runaway selection for particular male traits, such as first proposed by Fisher (1930).