Using Pearson’s System of Curves to Approximate the Distributions of the Difference between Two Correlated Estimates of Signal-to-Noise Ratios: The Cases of Bivariate Normal and Bivariate Lognormal Distributions

Background: The signal-to-noise ratio (SNR) is recognized as an index of measurements reproducibility. We derive the maximum likelihood estimators of SNR and discuss confidence interval construction on the difference between two correlated SNRs when the readings are from bivariate normal and bivariate lognormal distribution. We use the Pearsons system of curves to approximate the difference between the two estimates and use the bootstrap methods to validate the approximate distributions of the statistic of interest. Methods: The paper uses the delta method to find the first four central moments, and hence the skewness and kurtosis which are important in the determination of the parameters of the Pearsons distribution. Results: The approach is illustrated in two examples;one from veterinary microbiology and food safety data and the other on data from clinical medicine. We derived the four central moments of the target statistics, together with the bootstrap method to evaluate the parameters of Pearsons distribution. The fitted Pearsons curves of Types I and II were recommended based on the available data. The R-codes are also provided to be readily used by the readers.

Consistency in responses to conspecific advertisement calls with various signal-to-noise ratios in both sexes of the Anhui tree frog

Environmental noise has a significant negative impact on acoustic communication in most situations,as it influences the production,transmis-sion,and reception of acoustic signals.However,how animals respond to conspecific sounds when there is interference from environmental noise,and whether males and females display convergent behavioral responses in the face of noise masking remain poorly understood.In this study,we investigated the effects of conspecific male advertisement calls with different signal-to-noise ratios on male-male competition and female choice in the Anhui tree frog Rhacophorus zhoukaiyae using playback and phonotaxis experiments,respectively.The results showed that(1)female Anhui tree frogs preferentially selected the conspecific calls with higher SNR compared to calls with lower SNR;(2)males preferen-tially responded vocally to the conspecific calls with higher SNR compared to calls with lower SNR;and(3)males'competitive strategies were flexible in the face of noise interference.These results suggest that preferences of both sexes converge in outcome,and that male competitive strategies may depend on predictable female preferences.This study will provide an important basis for further research on decision-making in animals.

Isotopic dependence of the yield ratios of light fragments from different projectiles and their unified neutron skin thicknesses

The yield ratios of neutron-proton(R(n/p))and^(3)H-^(3)He(R(^(3)H∕^(3)He))with reduced rapidity from 0 to 0.5 were simulated at 50 MeV/u even-even ^(36−56)Ca+^(40)Ca,even-even ^(48−78)Ni+^(58)Ni,and ^(100−139)Sn(every third isotopes)+112 Sn for full reduced impact parameters using the isospin-dependent quantum molecular dynamics(IQMD)model.The neutron and proton density distributions and root-mean-square radii of the reaction systems were obtained using the Skyrme-Hartree-Fock model,which was used for the phase space initialization of the projectile and target in IQMD.We defined the unified neutron skin thickness asΔRnp=<r^(2)>^(1∕2) n−<r^(2)>^(1∕2)p,which was negative for neutron-deficient nuclei.The unifiedΔRnp values for nuclei with the same relative neutron excess from different isotopic chains were nearly equal,except for extreme neutron-rich isotopes,which is a type of scaling behavior.The yield ratios of the three isotopic chain-induced reactions,which depended on the reduced impact parameter and unified neutron skin thickness,were studied.The results showed that both R(n/p)and R(^(3)H∕^(3)He)decreased with a reduced impact parameter for extreme neutron-deficient isotopes;however,they increased with reduced impact parameters for extreme neutron-rich isotopes,and increased with theΔRnp of the projectiles for all reduced impact parameters.In addition,a scaling phenomenon was observed betweenΔR np and the yield ratios in peripheral colli-sions from different isotopic chain projectiles(except for extreme neutron-rich isotopes).Thus,R(n/p)and R(^(3)H∕^(3)He)from peripheral collisions were suggested as experimental probes for extracting the neutron or proton skin thicknesses of non-extreme neutron-rich nuclei from different isotopic chains.

Humic Acid Effects on Reducing Corn Leaf Burn Caused by Foliar Spray of Urea-Ammonium Nitrate at Different Humic Acid/Urea-Ammonium Nitrate Ratios

Technologies for reducing corn leaf burn caused by foliar spray of urea-ammonium nitrate (UAN) during the early growing season are limited. A field experiment was carried out to evaluate the effects of humic acid on corn leaf burn caused by foliar spray of undiluted UAN solution on corn canopy at Jackson, TN in 2018. Thirteen treatments of the mixtures of UAN and humic acid were evaluated at V6 of corn with different UAN application rates and different UAN/humic acid ratios. Leaf burn during 1 2, 3, 4, 5, 6, 7, and 14 days after UAN foliar spray significantly differed between with or without humic acid addition. The addition of humic acid to UAN significantly reduced leaf burn at each UAN application rate (15, 25, and 35 gal/acre). The reduction of leaf burn was enhanced as the humic acid/UAN ratio went up from 10% to 30%. Leaf burn due to foliar application of UAN became severer with higher UAN rates. The linear regression of leaf burn 14 days after application with humic acid/UAN ratio was highly significant and negative. However, the linear regression of leaf burn 14 days after application with the UAN application rate was highly significant and positive. In conclusion, adding humic acid to foliar-applied UAN is beneficial for reducing corn leaf burn during the early growing season.

Acquisition Practice of High Signal-to-Noise Ratio in YTB Block of Sichuan Basin

YTB block in Sichuan basin is a favorable area to exploit oil and gas in shallow tight rock. 3D seismic project of this zone has two characteristics. Firstly, it has high requirements for the tolerance rate of the construction process and the acquisition of high signal-to-noise ratio seismic data;Second, there are widely obstacles and noises that lead to difficult acquisition construction organization. In acquisition practice, high signal-to-noise ratio seismic data was obtained by reasonable design of construction scheme, optimization of excitation parameters, improvement of receiving conditions and optimization of obstacle crossing observation system. .

Calcium-Magnesium Ca/Mg Ratios and Their Agronomic Implications for the Optimization of Phosphate Fertilization in Rainfed Rice Farming on Acidic Ferralsol in the Forest Zone of Ivory Coast

This study is a contribution to improving rice productivity on acidic plateau soils of the tropical rainforest zone. It is based on taking into account the cationic balances of the soil in order to optimize the phosphorus (P) nutrition of rice on these acidic soils, where this nutrient constitutes a limiting factor for agricultural production. Three (3) pot trials were conducted in Adiopodoumé in the forested south of Côte d’Ivoire. The interactive effects of calcium carbonate (0, 25, 50 and 75 kg Ca ha−1) and magnesium sulfate (0, 25, 50 and 75 kg Mg ha−1) were evaluated on the response of NERICA 5 rice at doses 0, 25, 50 and 75 kg P ha−1 of natural phosphate from Togo, applied only once at the start of the experiment. Additional fertilizers of nitrogen (N) (100 kg N ha−1) and potassium (K) (50 kg KCl ha−1) were added to each of the tests in a split-plot device. The test results revealed a paddy production potential of approximately 3 to 5 t⋅ha−1 for NERICA 5 on an acidic soil, under the effect of the interaction of P, Ca and Mg. The quadratic response of rice yield to the doses of these fertilizers would be more dependent on their balance, itself influenced by Ca nutrition. For the sustainability and maintenance of rice production in agro-ecology studied, it was recommended doses of 38 kg Ca ha−1, 34 kg Mg ha−1 in a Ca/Mg ratio (1/1) with intakes of 41 kg P ha−1, overall in a ratio 1/1/1 (P/Ca/Mg) more favorable to the availability of free iron considered a guiding element of mineral nutrition. Thus, these promising results should be confirmed in a real environment for better management of the fertilization of rice cultivated on acidic plateau soils in Côte d’Ivoire.

基于改进Ratio统计量的重尾AR(p)时间序列均值变点检验

文章提出两个改进的Ratio统计量来研究重尾AR(p)时间序列均值变点检验问题,在原假设下推导了统计量的渐近分布,且在备择假设下证明了其一致性。由于重尾指数未知且难以估计,因此结合Wild Bootstrap重抽样方法来确定渐近分布的临界值;在均值变点存在的情形下,给出了变点位置的一致估计量。数值模拟结果表明:统计量的临界值均不受重尾指数和自回归系数的影响,其经验水平和经验势均取得满意的效果;尤其在原假设下,积分型Ratio统计量的经验水平表现出更好的稳健性,而在备择假设下,最值型Ratio统计量则具备更好的显著性。最后,基于一组股票数据,从实际应用角度进一步阐明所提方法的有效性和可行性。

Neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios alone or combined with prostate-specific antigen for the diagnosis of prostate cancer and clinically significant prostate cancer

Objective:We evaluated whether the blood parameters before prostate biopsy can diagnose prostate cancer(PCa)and clinically significant PCa(Gleason score[GS]7)in our hospital.Methods:This study included patients with increased prostate-specific antigen(PSA)up to 20 ng/mL.The associations of neutrophil-to-lymphocyte ratio(NLR)and platelet-tolymphocyte ratio(PLR)alone or with PSA with PCa and clinically significant PCa were analyzed.Results:We included 365 patients,of whom 52.9%(193)had PCa including 66.8%(129)with GS of≥7.PSA density(PSAD)and PSA had better the area under the curve(AUC)of 0.722 and 0.585,respectively with pZ0.001 for detecting PCa compared with other blood parameters.PSA combined with PLR(PsPLR)and PSA with NLR(PsNLR)had better AUC of 0.608 and 0.610,respectively with p<0.05,for diagnosing GS≥7 population,compared with PSA,free/total PSA,NLR,PLR,and PsNPLR(PSA combined with NLR and PLR).NLR and PLR did not predict PCa on multivariate analysis.For GS≥7 cancer detection,in the multivariate analysis,separate models with PSA and NLR(Model 1:PsNLRþbaseline parameters)or PSA and PLR(Moder 2:PsPLRþbaseline parameters)were made.Baseline parameters comprised age,digital rectal exam-positive lesions,PSA density,free/total PSA,and magnetic resonance imaging.Model 2 containing PsPLR was statistically significant(odds ratio:2.862,95% confidence interval:1.174-6.975,p=0.021)in finding aggressive PCa.The predictive accuracy of Model 2 was increased(AUC:0.734,p<0.001)than that when only baseline parameters were used(AUC:0.693,p<0.001).Conclusion:NLR or PLR,either alone or combined with PSA,did not detect PCa.However,the combined use of PSA with PLR could find the differences between clinically significant and insignificant PCa in our retrospective study limited by the small number of samples.

Effective DOA Estimation Under Low Signal-to-Noise Ratio Based on Multi-Source Information Meta Fusion

Efficiently performing high-resolution direction of arrival(DOA)estimation under low signal-to-noise ratio(SNR)conditions has always been a challenge task in the literatures.Obvi-ously,in order to address this problem,the key is how to mine or reveal as much DOA related in-formation as possible from the degraded array outputs.However,it is certain that there is no per-fect solution for low SNR DOA estimation designed in the way of winner-takes-all.Therefore,this paper proposes to explore in depth the complementary DOA related information that exists in spa-tial spectrums acquired by different basic DOA estimators.Specifically,these basic spatial spec-trums are employed as the input of multi-source information fusion model.And the multi-source in-formation fusion model is composed of three heterogeneous meta learning machines,namely neural networks(NN),support vector machine(SVM),and random forests(RF).The final meta-spec-trum can be obtained by performing a final decision-making method.Experimental results illus-trate that the proposed information fusion based DOA estimation method can really make full use of the complementary information in the spatial spectrums obtained by different basic DOA estim-ators.Even under low SNR conditions,promising DOA estimation performance can be achieved.

Signal-to-noise ratio of lensless ghost interference with thermal incoherent light

Factors influencing the signal-to-noise ratio （SNR） of lensless ghost interference with thermal incoherent light are investigated. Our result shows that the SNR of lensless ghost interference is related to the transverse length of the object, the position of the object in the imaging system and the transverse size of the light source. Furthermore, the effects of these factors on the SNR are discussed in detail by numerical simulations.

Noises and Signal-to-Noise Ratio of Nanosize EIS and ISFET Biosensors

The results of comparative theoretical analyzes of the behavior of internal low-frequency noises, signal-to-noise ratio and sensitivity to DNA molecules for EIS and ISFET based nanosize biosensors are presented. It is shown that EIS biosensor is more sensitive to the presence of DNA molecules in aqueous solution than ISFET sensor. Internal electrical noises level decreases with the increase of concentration of DNA molecules in aqueous solution. In the frequency range 10&minus;3 - 103 Hz noises level for EIS sensor about in three orders is higher than for ISFET sensor. In the other hand, signal-to-noise ratio for capacitive EIS biosensor is much higher than for ISFET sensor.

Investigations on Fluid Resonance Within A Narrow Gap Formed by Two Fixed Bodies with Varying Breadth Ratios

The resonant motion of the fluid inside a narrow gap between two fixed boxes induced by incident regular waves with various wave heights is investigated by adopting a two-dimensional numerical wave flume based on an opensourced CFD package,OpenFOAM.The two boxes have identical draft and height,but the upstream box has a variable breadth.This article focuses on the influences of the breadth ratio,defined as the ratio of the breadth of the upstream box to that of the downstream box,on the following three aspects of hydrodynamic characteristics of gap resonance:(1)the wave height amplifications inside the gap,and in front and at the rear of the structure system,(2)the reflection,transmission,and energy loss coefficients of the structure system,and(3)the response and damping time of the fluid resonance.It is found that the fluid resonant frequency,the amplification factor of the resonant wave height inside the gap and the maximum energy loss coefficient of the structure system are shown to gradually decrease with the increase of the breadth ratio.The response time of gap resonance is shown to first increase and then decrease with the breadth ratio overall,regardless of the incident wave height,and the configuration that the two boxes have the same breadth would bring the largest response time of gap resonance.

Experimental Investigation of Multi-Mode Vortex-Induced Vibration of Flexible Risers with Different Mass Ratios

Experiments were conducted on risers with different mass ratios to study the effect of mode conversion and spanwise correlation. The slenderness ratio of the riser model was set as 169, and the Reynolds numbers are 1600-14400. The dynamic responses of riser models versus reduced velocity were analyzed, and the spanwise displacement, frequency,and trajectory of the mode conversion from the lower to the higher mode were explored. The results revealed that the riser model with a higher mass ratio excites a higher number of modes. The conversion region of multi-mode competition exists and narrows with the increasing mass ratio. Mode conversion is continuous and manifests as the transmission of peaks and troughs in mode shape: the peaks and troughs of mode shape move up in the mode stable development region and move down in the mode conversion region. The single-mode dominating vibration exhibits a standing wave feature, and the traveling wave feature is significant in the mode conversion region. Furthermore, the frequency jump is always transmitted from the trough to the peak of the mode shape, and finally, all the axial positions vibrate at the same frequency. The trajectory in the mode conversion region deviates from the 8-shape and recovers the standard8-shape at the middle and late stages of the mode stable development region.

Enhancement of signal-to-noise ratio of ultracold polar NaCs molecular spectra by phase locking detection

We report a method of high-sensitively detecting the weak signal in photoassociation （PA） spectra of ultracold NaCs molecules by phase sensitive-demodulated trap-loss spectra of Na atoms from a photomultiplier tube. We find that the signal-to-noise ratio （SNR） of the PA spectra is strongly dependent on the integration time and the sensitivity of the lock-in amplifier, and our results show reasonable agreement with the theoretical analyses of the SNR with the demodulation parameters. Meanwhile, we investigate the effect of the interaction time of the PA laser with the colliding Na-Cs atom pairs on the SNR of the PA spectra. The atom loss rate is dependent on both the PA-induced atom loss and the loading of the MOT. The high-sensitive detection of the excited ultracold NaCs molecules lays a solid foundation for further study of the formation and application of ultracold NaCs molecules.

Signal-to-noise ratio of Raman signal measured by multichannel detectors

Raman spectroscopy has been widely used to characterize the physical properties of two-dimensional materials(2DMs).The signal-to-noise ratio(SNR or S/N ratio)of Raman signal usually serves as an important indicator to evaluate the instrumental performance rather than Raman intensity itself.Multichannel detectors with outstanding sensitivity,rapid acquisition speed and low noise level have been widely equipped in Raman instruments for the measurement of Raman signal.In this mini-review,we first introduce the recent advances of Raman spectroscopy of 2DMs.Then we take the most commonly used CCD detector and IGA array detector as examples to overview the various noise sources in Raman measurements and analyze their potential influences on SNR of Raman signal in experiments.This overview can contribute to a better understanding on the SNR of Raman signal and the performance of multichannel detector for numerous researchers and instrumental design for industry,as well as offer practical strategies for improving spectral quality in routine measurement.

Experimental Study on Interference Effect of Three Risers Arranged in Tandem with Variable Spacing Ratios

Taking the three-riser group arranged in tandem as the research subject,an experimental study was carried out on the risers arranged in tandem.The purpose is to explore the sensitivity of the dynamic response of each riser to spacing ratio and reveal the physical mechanism of riser groups under the interference effect.The spacing ratios of the adj acent risers are 4.0,5.0,6.0,and 8.0.At the spacing between the risers of 4.0D,the strong feedback effect increases the cross-flow(CF) displacement amplitude of the upstream riser.The shielding effect is the key factor affecting the interference effect on the midstream and downstream risers.At low reduced velocities,the shielding area initially appears,the displacement amplitude of the midstream and downstream risers varies greatly,the vibration of the two risers is still dominated by the first-order mode,and the transition between adjacent vibration modes is restrained.The multi-frequency superposition phenomenon is very significant at high reduced velocities.The most sensitive interference spacing under the test conditions is obtained.Due to the separation of the incoming flow and the double shielding effect of the upstream and midstream risers,the regular vortex-induced vibration in the wake area of the downstream riser is broken,and the vibration in the two directions is weakened.In general,the interference effect is more significant for the CF vibration of the three-riser groups than the in-line(IL) vibration.

Signal-to-noise ratio comparison of angular signal radiography and phase stepping method

Grating-based x-ray phase contrast imaging has the potential to be applied in future medical applications as it is compatible with both laboratory and synchrotron source. However, information retrieval methods are important because acquisition speed, scanning mode, image quality, and radiation dose depend on them. Phase-stepping （PS） is a widely used method to retrieve information, while angular signal radiography （ASR） is a newly established method. In this manuscript, signal-to-noise ratios （SNRs） of ASR are compared with that of PS. Numerical experiments are performed to validate theoretical results. SNRs comparison shows that for refraction and scattering images ASR has higher SNR than PS method, while for absorption image both methods have same SNR. Therefore, our conclusions would have guideline in future preclinical and clinical applications.

A new strategy for ionospheric remote sensing using the 130.4/135.6 nm airglow intensity ratios

We demonstrate here that global-scale determination of a key ionospheric parameter,the peak height of the F_(2)region(h_(m)F_(2)),can be obtained by making a simple ratio measurement of the atomic oxygen 130.4 and 135.6 nm emissions in the far-ultraviolet nightglow with a nadir-viewing system such as a pair of photometers suitable for flight on a CubeSat.We further demonstrate that measurements from an altitude that is within the typical range of nighttime h_(m)F_(2)250−450 km can provide the ratios that are needed for retrieval of the h_(m)F_(2).Our study is conducted mostly through numerical simulations by using radiative transfer models of the two emissions coupled with empirical models of the atmosphere and ionosphere.Modeling results show that the relationship between the h_(m)F_(2)and the intensity ratio is sensitive to the altitude from which the emissions are observed,primarily because of the distinctly different degrees of resonant scattering of the two emissions in the atmosphere.A roughly quadratic relationship can be established for observations from an orbit of~400 km,which enables h_(m)F_(2)retrieval.Parametric analysis indicates that the relationship can be affected by the ambient atmospheric conditions through resonant scattering and O2 absorption.For typical nighttime conditions with h_(m)F_(2)250−450 km,retrieval of the h_(m)F_(2)from synthetic observations shows that the typical errors are only a few kilometers(up to~20 km),depending on the accuracy of the ambient conditions predicted by the empirical models.Our findings pave the way for use of the 130.4/135.6 nm intensity ratios for global-scale monitoring of the nighttime ionosphere at mid to low latitudes.

Morphotype dependence of Globigerinoides ruber(white)and Trilobatus sacculifer Mg/Ca ratios in the western tropical Pacific:implications for reconstructing the mixed-layer depth

Planktonic foraminifer Globigerinoides ruber(white)and Trilobatus sacculifer are the most frequently used mixedlayer dwelling species for reconstructing past oceanic environments.Specifically,the Mg/Ca ratios of these two foraminiferal species have been used for reconstructing tropical/subtropical changes in sea surface temperature(SST).However,these two species have different morphotypes,of which the spatial and temporal differences in Mg/Ca ratios and their influencing factors are still unclear.Our objective is to investigate the potential differences between the Mg/Ca ratios of these different morphotypes of G.ruber(white)and T.sacculifer in the western Philippine Sea(WPS)and determine their implications for the reconstruction of SST and upper-ocean structure.Mg/Ca measurements are made on two basic morphotypes of G.ruber(white)[sensu stricto(s.s.)and sensu lato(s.l.)]and T.sacculifer[with(w)and without(w/o)a sac-like final chamber]on samples of Site MD06-3047B from the WPS.Our results reveal that Mg/Ca ratios of different G.ruber morphotypes show consistent differences;and those of T.sacculifer morphotypes show staged variations since MIS 3.It is suggested to select a single morphotype for reconstructing SST changes using the Mg/Ca ratios of G.ruber and T.sacculifer in the WPS.Furthermore,the Mg/Ca ratios between G.ruber s.s.and G.ruber s.l.[Δ(Mg/Ca)_(G.ruber s.s.-s.l.)]downcore MD06-3047B covaries with indexes of summer monsoon.Combining with the core-top results,showing regional variation of differences in theΔ(Mg/Ca)_(G.ruber s.s.-s.l.)over the western tropical Pacific,we propose thatΔ(Mg/Ca)_(G.ruber s.s.-s.l.)may tend to reflect summer mixed layer depth.

The Impact of Different Mining and Releasing Ratios on the Over-Support Pressure of Header Working Face

Through the theoretical analysis of overburden destabilization mechanism, FLAC 3D simplified plane numerical simulation method and field measurement method, we compared the relationship of overburden support pressure at 35 m of workface recovery, and the peak overburden support pressure decreased from 13.85 Mpa to 11.97 Mpa from 1:1 to 1:3. With the increase of mining ratio, the peak over-supporting pressure decreases: with the increase of top coal recovery thickness, the peak over-supporting pressure and the influence range will be further expanded, and the distance between the peak over-supporting pressure and the coal wall of the working face will be further increased and the high stress zone of the peak area will be expanded simultaneously.