Objectives:This study aimed to develop a nomogram for predicting the risk of pressure injury(PI)in adult patients undergoing abdominal surgery and validate its effectiveness among these patients.Methods:This study ret...Objectives:This study aimed to develop a nomogram for predicting the risk of pressure injury(PI)in adult patients undergoing abdominal surgery and validate its effectiveness among these patients.Methods:This study retrospectively included 11,247 adult patients,who underwent abdominal surgery and postoperative supervision in ICU,in a tertiary care hospital in western China between January 2017 and December 2020.All datasets were extracted from the patient’s medical records and randomly divided into the training cohort(8,997)and the validation cohort(2,250)by 8:2.The univariable logistic regression was used to select potentially relevant features.Then,multivariable logistic regression was also conducted and utilized to establish the nomogram.The nomogram was compared with the Braden scale for predicting PI in the validation cohort through the area under the curve(AUC)of the receiver operator characteristic(ROC)curve,Hosmer-Lemeshow(H-L)test,and decision curve analysis(DCA).Results:873(7.8%)patients suffered PIs.Logistic regression analysis showed that time of operation,weight,type of operation,albumin,and Braden scale score were independent risk factors for PI.A nomogram integrating five selected characteristics was constructed.The AUC of the ROC curve for the nomogram was 0.831,with a specificity of 85.2%and sensitivity of 63.7%.The AUC of the ROC curve for the Braden scale was 0.567,with a specificity of only 33.0%.The P-values of the H-L test were 0.45(nomogram)and 0.22(Braden scale),both indicating good calibration.The DCA also displayed that the nomogram had better predictive validity.Conclusion:Compared with the Braden scale,the nomogram showed a better predictive performance.This nomogram is informative and has the potential to better guide caregivers for risk stratification and prevention of PI,although it requires further validation.展开更多
This paper proposes a risk assessment model considering danger zone,capsizing time,and evaluation time factors(DCEFM)to quantify the emergency risk of ship inflow and calculate the degree of different factors to the e...This paper proposes a risk assessment model considering danger zone,capsizing time,and evaluation time factors(DCEFM)to quantify the emergency risk of ship inflow and calculate the degree of different factors to the emergency risk of water inflow.The DCEFM model divides the water inflow risk factors into danger zone,capsizing time,and evacuation time factors.The danger zone,capsizing time,and evacuation factors are calculated on the basis of damage stability probability,the numerical simulation of water inflow,and personnel evacuation simulation,respectively.The risk of a capsizing scenario is quantified by risk loss.The functional relationship between the location of the danger zone and the probability of damage,the information of breach and the water inflow time,the inclination angle and the evacuation time,and the contribution of different factors to the risk model of ship water inflow are obtained.Results of the DCEFM show that the longitudinal position of the damaged zone and the area of the breach have the greatest impact on the risk.A simple local watertight plate adjustment in the high-risk area can improve the safety of the ship.展开更多
This paper presents a curve reconstruction algorithm based on discrete data points and normal vectors using B-splines.The proposed algorithm has been improved in three steps:parameterization of the discrete data point...This paper presents a curve reconstruction algorithm based on discrete data points and normal vectors using B-splines.The proposed algorithm has been improved in three steps:parameterization of the discrete data points with tangent vectors,the B-spline knot vector determination by the selected dominant points based on normal vectors,and the determination of the weight to balancing the two errors of the data points and normal vectors in fitting model.Therefore,we transform the B-spline fitting problem into three sub-problems,and can obtain the B-spline curve adaptively.Compared with the usual fitting method which is based on dominant points selected only by data points,the B-spline curves reconstructed by our approach can retain better geometric shape of the original curves when the given data set contains high strength noises.展开更多
Since the realization of Bose Einstein condensation(BEC)[1-3]and degenerate Fermi gases[4],ultracold quantum gases have become important platforms to study quantum phenomena and novel states of matter with precise con...Since the realization of Bose Einstein condensation(BEC)[1-3]and degenerate Fermi gases[4],ultracold quantum gases have become important platforms to study quantum phenomena and novel states of matter with precise control over both internal and external degrees of freedom.While quantum gases arc typically dilute and weakly interacting,the interactions intrinsically determine their essential properties,such as the superfluidity of a BEC.展开更多
Advancements in microwave photonics have yielded novel approaches for generating high-purity microwave sources.Among these,optoelectronic oscillators(OEOs)and coupled optoelectronic oscillators(COEOs)have demonstrated...Advancements in microwave photonics have yielded novel approaches for generating high-purity microwave sources.Among these,optoelectronic oscillators(OEOs)and coupled optoelectronic oscillators(COEOs)have demonstrated the capability to generate frequency-independent microwaves with exceptionally low phase noise.Nonetheless,the tunability of the oscillators is rather limited due to the necessity for narrowband electronic bandpass filters,presenting challenges in achieving both wide and rapid tuning capabilities.Here,we present a COEO featuring ultralow phase noise,flexible tuning capability,and high robustness.This is achieved through a quiet point(QP)-operated harmonic mode-locked fiber laser,which effectively mitigates optical amplifier noise and supermode competition,thus significantly diminishing the necessity for ultra-narrow electronic filters.Due to the liberated tuning ability,we present an oscillator that can be tuned from 2 GHz to 18 GHz,with phase noise as low as-140 d Bc/Hz at 10 k Hz under the QP operation.We then illustrate the practical application of the proposed oscillator in generating frequency-hopping signals with consistent spurious modes less than-85 d Bc,absolute phase noise below-135 d Bc/Hz at 10 k Hz,hopping resolution of 1.25 MHz,and fractional frequency stability below 6.1×10^(-12)at 1 s averaging time when locked to a reference.The presented COEO structure emerges as a compelling solution for agile and low-noise microwave sources in advanced wireless communication and radar systems.展开更多
文摘Objectives:This study aimed to develop a nomogram for predicting the risk of pressure injury(PI)in adult patients undergoing abdominal surgery and validate its effectiveness among these patients.Methods:This study retrospectively included 11,247 adult patients,who underwent abdominal surgery and postoperative supervision in ICU,in a tertiary care hospital in western China between January 2017 and December 2020.All datasets were extracted from the patient’s medical records and randomly divided into the training cohort(8,997)and the validation cohort(2,250)by 8:2.The univariable logistic regression was used to select potentially relevant features.Then,multivariable logistic regression was also conducted and utilized to establish the nomogram.The nomogram was compared with the Braden scale for predicting PI in the validation cohort through the area under the curve(AUC)of the receiver operator characteristic(ROC)curve,Hosmer-Lemeshow(H-L)test,and decision curve analysis(DCA).Results:873(7.8%)patients suffered PIs.Logistic regression analysis showed that time of operation,weight,type of operation,albumin,and Braden scale score were independent risk factors for PI.A nomogram integrating five selected characteristics was constructed.The AUC of the ROC curve for the nomogram was 0.831,with a specificity of 85.2%and sensitivity of 63.7%.The AUC of the ROC curve for the Braden scale was 0.567,with a specificity of only 33.0%.The P-values of the H-L test were 0.45(nomogram)and 0.22(Braden scale),both indicating good calibration.The DCA also displayed that the nomogram had better predictive validity.Conclusion:Compared with the Braden scale,the nomogram showed a better predictive performance.This nomogram is informative and has the potential to better guide caregivers for risk stratification and prevention of PI,although it requires further validation.
基金Supported by the National Natural Science Foundation of China(51509060)the Natural Science Foundation of Heilongjiang Province of China(YQ2021E014).
文摘This paper proposes a risk assessment model considering danger zone,capsizing time,and evaluation time factors(DCEFM)to quantify the emergency risk of ship inflow and calculate the degree of different factors to the emergency risk of water inflow.The DCEFM model divides the water inflow risk factors into danger zone,capsizing time,and evacuation time factors.The danger zone,capsizing time,and evacuation factors are calculated on the basis of damage stability probability,the numerical simulation of water inflow,and personnel evacuation simulation,respectively.The risk of a capsizing scenario is quantified by risk loss.The functional relationship between the location of the danger zone and the probability of damage,the information of breach and the water inflow time,the inclination angle and the evacuation time,and the contribution of different factors to the risk model of ship water inflow are obtained.Results of the DCEFM show that the longitudinal position of the damaged zone and the area of the breach have the greatest impact on the risk.A simple local watertight plate adjustment in the high-risk area can improve the safety of the ship.
基金Supported by the National Natural Science Foundation of China(Nos.1187113711572081)the Program for Liaoning Innovation Talents in University(No.LCR2018001)
文摘This paper presents a curve reconstruction algorithm based on discrete data points and normal vectors using B-splines.The proposed algorithm has been improved in three steps:parameterization of the discrete data points with tangent vectors,the B-spline knot vector determination by the selected dominant points based on normal vectors,and the determination of the weight to balancing the two errors of the data points and normal vectors in fitting model.Therefore,we transform the B-spline fitting problem into three sub-problems,and can obtain the B-spline curve adaptively.Compared with the usual fitting method which is based on dominant points selected only by data points,the B-spline curves reconstructed by our approach can retain better geometric shape of the original curves when the given data set contains high strength noises.
文摘Since the realization of Bose Einstein condensation(BEC)[1-3]and degenerate Fermi gases[4],ultracold quantum gases have become important platforms to study quantum phenomena and novel states of matter with precise control over both internal and external degrees of freedom.While quantum gases arc typically dilute and weakly interacting,the interactions intrinsically determine their essential properties,such as the superfluidity of a BEC.
基金National Natural Science Foundation of China(61971065,62171055)Beijing Municipal Natural Science Foundation(Z210004)。
文摘Advancements in microwave photonics have yielded novel approaches for generating high-purity microwave sources.Among these,optoelectronic oscillators(OEOs)and coupled optoelectronic oscillators(COEOs)have demonstrated the capability to generate frequency-independent microwaves with exceptionally low phase noise.Nonetheless,the tunability of the oscillators is rather limited due to the necessity for narrowband electronic bandpass filters,presenting challenges in achieving both wide and rapid tuning capabilities.Here,we present a COEO featuring ultralow phase noise,flexible tuning capability,and high robustness.This is achieved through a quiet point(QP)-operated harmonic mode-locked fiber laser,which effectively mitigates optical amplifier noise and supermode competition,thus significantly diminishing the necessity for ultra-narrow electronic filters.Due to the liberated tuning ability,we present an oscillator that can be tuned from 2 GHz to 18 GHz,with phase noise as low as-140 d Bc/Hz at 10 k Hz under the QP operation.We then illustrate the practical application of the proposed oscillator in generating frequency-hopping signals with consistent spurious modes less than-85 d Bc,absolute phase noise below-135 d Bc/Hz at 10 k Hz,hopping resolution of 1.25 MHz,and fractional frequency stability below 6.1×10^(-12)at 1 s averaging time when locked to a reference.The presented COEO structure emerges as a compelling solution for agile and low-noise microwave sources in advanced wireless communication and radar systems.
