Kp Method Research Articles

An Update to the Kaiser Permanente Inpatient Risk Adjustment Methodology Accurately Predicts In-Hospital Mortality: a Retrospective Cohort Study.

Methods to accurately predict the risk of in-hospital mortality are important for applications including quality assessment of healthcare institutions and research. To update and validate the Kaiser Permanente inpatient risk adjustment methodology (KP method) to predict in-hospital mortality, using open-source tools to measure comorbidity and diagnosis groups, and removing troponin which is difficult to standardize across modern clinical assays. Retrospective cohort study using electronic health record data from GEMINI. GEMINI is a research collaborative that collects administrative and clinical data from hospital information systems. Adult general medicine inpatients at 28 hospitals in Ontario, Canada, between April 2010 and December 2022. The outcome was in-hospital mortality, modeled by diagnosis groupusing 56 logistic regressions. We compared models with and without troponin as an input to the laboratory-based acute physiology score. We fit and validated the updated method using internal-external cross-validation at 28 hospitals from April 2015 to December 2022. In 938,103 hospitalizations with 7.2% in-hospital mortality, the updated KP method accurately predicted the risk of mortality. The c-statistic at the median hospital was 0.866 (see Fig. 3) (25th-75th 0.848-0.876, range 0.816-0.927) and calibration was strong for nearly all patients at all hospitals. The 95th percentile absolute difference between predicted and observed probabilities was 0.038 at the median hospital (25th-75th 0.024-0.057, range 0.006-0.118). Model performance was very similar with and without troponin in a subset of 7 hospitals, and performance was similar with and without troponin for patients hospitalized for heart failure and acute myocardial infarction. An update to the KP method accurately predicted in-hospital mortality for general medicine inpatients in 28 hospitals in Ontario, Canada. This updated method can be implemented in a wider range of settings using common open-source tools.

EVALUASI KEBUTUHAN DAN KETERSEDIAAN AIR IRIGASI DALAM RANGKA PENINGKATAN HASIL PERTANIAN

The availability of water in irrigation areas can affect agricultural productivity. Water balance must be maintained so that there is no shortage of water. Cikunten II has an area of 4.362 ha, mostly in the Tasikmalaya district. This study aims to analyze the water requirement and balance. Data analysis used the KP01 guidelines and the Cropwat program. The data analysis results obtained differences in reference plants' evapotranspiration results using the Modified Penman method in KP and Pennman–Monteith in the Cropwat program. The difference between the two methods is 133,83% due to the difference in albedo coefficients. The effective rainfall for paddy and secondary crops, the KP method analysis is lower than the Cropwat simulation of 110.10%. Availability of water using data from the Ciwulan weir with a reliability of 80% obtained a maximum discharge of 2,73 m3/sec. The water requirement was calculated during planting periods I, II, and II. The KP method is greater than the Cropwat method with a percentage of 277.42% in analyzing water requirements in the Paddy-Paddy-plants cropping pattern. The availability of water in the Cikunten area using Cropwat has fulfilled the needs marked by a more stable k factor than the KP01 method.

A wheel–rail normal contact model using the combination of virtual penetration method and strip-like Boussinesq’s integral

This paper reports a new non-Hertz normal contact model for the engineering computations such as vehicle-track dynamics and wheel-rail damage prediction. The model is developed as a combination of virtual penetration method and Boussinesq’s integral. A first novel aspect is the proposed virtual penetration method to compensate the inconsistence introduced by this combination, (i) a ‘stepwise penetration scaling coefficient’ approach that adapts to the lateral contact boundary is presented; (ii) we propose a new formula for the longitudinal contact boundary to compensate the error introduced by the step-by-step increase of interpolated penetration. A second novelty is the use of strip-like Boussinesq’s integral for strip discretized contact patch to achieve the fast computation. On the one hand, it makes this model easier to convergence since it only considers the result in the center of each strip. On the other hand, we propose a fast method of generating influence coefficient matrix. Some numerical tests are evaluated by the CONTACT software and compared with KP method and STRIPES. In addition, the comparison of modeling approach and computational cost are discussed in detail.

The engineering of Weyl nodes and Dirac-like energy dispersion for topological surface states in Hg[formula omitted]MnxTe under structure and interface inversion asymmetry

From Dirac semimetal to Weyl semimetal, a break inversion of time-inversion symmetry (TIS) or inversion symmetry (IS) is required - from this point of view, the possibility of breaking symmetry in HgMnTe alloys is examined in a zincblende structure and the results of numerical calculations are presented in this paper. Low x-Mn (x < 0.04) content in HgMnTe causes a larger strain-induced gap (than in 3D 75-nm strained HgTe) which can be found in the investigated material. As shown, structure inversion asymmetry (SIA) and interface inversion asymmetry (IIA) play a crucial role in the case of Weyl nodes, which should be observed in the investigated material. In both (3D and 2D) systems the SIA is very important as a factor that can be used to modify the obtained energy dispersion for the topological surfaces states (TSS) (in the case of 3D systems) and edge states (in 2D systems). The theoretical investigation presented in this paper based on the eight band kp model allows calculation of the energy spectrum along the entirety of the investigated structures. An external magnetic field is also taken into account. This is the first time that such analysis based on the 8 × 8 kp method has been used to interpenetrate both the surface states and the bulk states for 3D and 2D HgMnTe material under a magnetic field. The obtained results show the entire scope of the energy spectrum and clearly demonstrate that both of the investigated systems are very interesting from application points of view e.g. for terahertz detectors in a magnetic field below 2 T.

Spin-orbit coupling in strained Ge whiskers

The field dependences of the magnetoresistance for germanium whiskers with gallium doping concentration of 2 ⋅ 1017 cm-3 were studied in the magnetic field range 0–14 T at temperature 4.2 K under compressive strain up to 0.2%. The strain influence on a spin-orbit splitting on the valence band spectrum was studied. As a result, the effective mass and the energies of spin-orbit splitting for light and heavy holes were found under the compressive strain according to kp method. From an analysis of the Shubnikov—de Haas magnetoresistance oscillations the effective mass of heavy holes mc = 0.25 m0 was calculated. The spin-orbit splitting energy of heavy holes ΔHH = 15 meV, the Lande factor in direction [111] g* = 4.8 as well as the Rashba cubic parameter of spin-orbit interaction βSO=1⋅10−28eV⋅m3 were found due to the studying of longitudinal magnetoconductance in strained Ge whiskers at low temperatures. The appearance of negative magnetoresistance in the magnetic field range up to 7 T likely results from the effect of charge carrier interaction.

Long-Term Survival and Local Control Outcomes in Oligometastatic Colorectal Cancer Treated with Liver Stereotactic Body Radiation Therapy

The purpose of the present study was to evaluate clinical outcomes following stereotactic body radiation therapy (SBRT) in patients with liver metastases (LM) due to colorectal cancer (CRC). This was a single-institution retrospective study of patients included in a prospectively maintained institutional database. Outcome endpoints included overall survival (OS) and local control (LC). We also performed assessments for predictors of LC and OS including evaluation of BED10 less than or greater than 150. Eligible patients had LM due to CRC, were treated with SBRT between 2007-2018, and had at least 3 months of follow up. Median SBRT dose was 54 Gy (range 32-60 Gy) in 3 fractions (range 3-5), and median BED10 was 151.0 Gy. All survival times were calculated from the start date of SBRT. Kaplan-Meier curves were used to estimate actuarial survival times, and Cox regression was used for multivariable analysis (MVA) of predictors of OS. We identified 67 eligible patients and 15/67 (22%) of patients had prior partial hepatectomy. Median number of chemotherapy regimens prior to SBRT was 1 (range 0-3). The majority of patients (79.6%) had a solitary liver metastasis; 2 had extrahepatic disease at the time of SBRT. The maximum number of treated LM was 3. Median tumor diameter was 2.7 cm (range 0.4-5.6). At a median follow up of 42.5 mos (range 3-96), 27/67 patients (40.2%) of patients had died. The median estimated OS (KP method) in this patient cohort was 64.0 months (95% CI 41.6 - Not Estimable (NE)). Estimated median KP duration of local control was 71.4 months (95% CI: 38.5, NE) in the entire patient cohort. Duration of local control was statistically significantly better in patients with liver SBRT treatment where the BED was > 150. The median duration of LC in patients with liver SBRT plans with BED10 > 150 was 74.4-months (95% CI: 40.1, NE) vs 26.1 month (95%: CI 11.6 – NE) in those with liver SBRT plan with BED < 150 (p=0.0006). The median KP estimated OS was 82.4 months (95% CI: 41.4 – NE) in patients with SBRT plan > 150 vs 62.8 months (95% CI: 36.2 mo. – NE) in those with BED < 150 (p= 0.697). Duration of local control was found to significantly correlate with OS. The hazard of death was reduced by 5.1% for each additional month of local control. GTV size (cc), diameter of treated metastases, and presence of K-ras mutation did not appear to be a predictor of LC in our patient cohort. SBRT is very effective in the management of hepatic oligometastases and was associated with an estimated median OS greater than 5 years in select patients. In this study, we found that duration of local control was significantly associated with overall survival. Additionally, it appears from this series that BED10 > 150 is associated with increase in local control.

Prediction of Tissue-Plasma Partition Coefficients Using Microsomal Partitioning: Incorporation into Physiologically based Pharmacokinetic Models and Steady-State Volume of Distribution Predictions.

Drug distribution is a necessary component of models to predict human pharmacokinetics. A new membrane-based tissue-plasma partition coefficient (K p) method (K p,mem) to predict unbound tissue to plasma partition coefficients (K pu) was developed using in vitro membrane partitioning [fraction unbound in microsomes (f um)], plasma protein binding, and log P The resulting K p values were used in a physiologically based pharmacokinetic (PBPK) model to predict the steady-state volume of distribution (V ss) and concentration-time (C-t) profiles for 19 drugs. These results were compared with K p predictions using a standard method [the differential phospholipid K p prediction method (K p,dPL)], which differentiates between acidic and neutral phospholipids. The K p,mem method was parameterized using published rat K pu data and tissue lipid composition. The K pu values were well predicted with R 2 = 0.8. When used in a PBPK model, the V ss predictions were within 2-fold error for 12 of 19 drugs for K p,mem versus 11 of 19 for Kp,dPL With one outlier removed for K p,mem and two for K p,dPL, the V ss predictions for R 2 were 0.80 and 0.79 for the K p,mem and K p,dPL methods, respectively. The C-t profiles were also predicted and compared. Overall, the K p,mem method predicted the V ss and C-t profiles equally or better than the K p,dPL method. An advantage of using f um to parameterize membrane partitioning is that f um data are used for clearance prediction and are, therefore, generated early in the discovery/development process. Also, the method provides a mechanistically sound basis for membrane partitioning and permeability for further improving PBPK models. SIGNIFICANCE STATEMENT: A new method to predict tissue-plasma partition coefficients was developed. The method provides a more mechanistic basis to model membrane partitioning.

Particle Swarm Optimization of PID Controller under Constraints on Performance and Robustness

This paper presents a design procedure of the PID controller where optimal parameters of controller * * * *p i d f (k ,k ,k ,T ) areobtained by solving the constrained optimization problem. The objective function is given in the form of the Integral of Absolute Error(IAE) under specifications to achieve predictable performance and robustness. The constraints within the optimization problem setupare desired maximum sensitivity, desired maximum complementary sensitivity and maximum sensitivity to measurement noise underhigh frequencies. The optimization problem is transformed to an unconstrained problem using penalty function approach. Solution tothe optimization problem is obtained using Particle Swarm algorithm (PSO) which leads to an efficient suppression of disturbance aswell as an adequate reference tracking performance of the closed-loop system with negligible overshoot. The suggested method isapplicable to the large class of stable, integral and unstable processes, processes with oscillatory dynamics with and without dead-time.Effectiveness of the proposed design procedure is verified via numerical simulations on test batch consisting of processes typicallyencountered in industry. Paper also provides two another solutions of the defined optimization problem using genetic algorithm (GA)and fminunc trust region based approach (TR). Performance of the PSO, GA, and TR based control system is compared with thoseusing recently proposed maximization of proportional gain denoted with max(kp) method. Although the present paper is focused to tunethe PID controller, the same procedure may be used to design PI controller, lead and lag compensators, high-order controllers as well asfractional-order controllers.

Zeeman Splitting of Electron Spectrum in HgTe Quantum Wells Near the Dirac Point

The Zeeman splitting of the conduction band in the HgTe quantum wells both with normal and inverted spectrum has been studied experimentally in a wide electron density range. The simultaneous analysis of the Shubnikov–de Haas oscillations in low magnetic fields at different tilt angles and of the shape of the oscillations in moderate magnetic fields gives a possibility to find the ratio of the Zeeman splitting to the orbital one and anisotropy of g-factor. It is shown that the ratios of the Zeeman splitting to the orbital one are close to each other for both types of structures, with a normal and inverted spectrum and they are close enough to the values calculated within kP method. In contrast, the values of g-factor anisotropy in the structures with normal and inverted spectra are strongly different and for both cases differ significantly from the calculated ones. We assume that such disagreement with calculations is a result of the interface inversion asymmetry in the HgTe quantum well, which is not taken into account in the kP calculations.

Zeeman splitting of electron spectrum in HgTe quantum wells near the Dirac point

AbstractThe Zeeman splitting of the conduction band in the HgTe quantum wells both with normal and inverted spectrum has been studied experimentally in a wide electron density range. The simultaneous analysis of the Shubnikov–de Haas oscillations in low magnetic fields at different tilt angles and of the shape of the oscillations in moderate magnetic fields gives a possibility to find the ratio of the Zeeman splitting to the orbital one and anisotropy of g -factor. It is shown that the ratios of the Zeeman splitting to the orbital one are close to each other for both types of structures, with a normal and inverted spectrum and they are close enough to the values calculated within kP method. In contrast, the values of g -factor anisotropy in the structures with normal and inverted spectra are strongly different and for both cases differ significantly from the calculated ones. We assume that such disagreement with calculations is a result of the interface inversion asymmetry in the HgTe quantum well, which is not taken into account in the kP calculations.

Kp method for heterostructures

We show that widely used method of spectrum calculation in heterostructures based on effective mass approximation in each separate layer gives wrong results for the in-plane spectrum. We develop a new approach that is effective mass approximation in the growth direction and kp method for the whole structure for the in-plane spectrum. This approach is demonstrated for single infinite quantum well and double well structure.

Zeeman splitting of conduction band in HgTe quantum wells near the Dirac point

The Zeeman splitting of the conduction band in the HgTe quantum wells both with normal and inverted spectrum has been studied experimentally in a wide electron density range. The simultaneous analysis of the Shubnikov-de Haas (SdH) oscillations in low magnetic fields at different tilt angles and of the shape of the oscillations in moderate magnetic fields gives a possibility to find the ratio of the Zeeman splitting to the orbital one and anisotropy of g-factor. It is shown that the ratios of the Zeeman splitting to the orbital one are close to each other for both types of structures, with a normal and inverted spectrum and they are close enough to the values calculated within kP method. In contrast, the values of g-factor anisotropy in the structures with normal and inverted spectra are strongly different and for both cases differ significantly from the calculated ones. We assume that such disagreement with calculations is a result of the interface inversion asymmetry in the HgTe quantum well, which is not taken into account in the kP calculations.

Multicolor emission from intermediate band semiconductor ZnO1\u2212xSex

Photoluminescence and photomodulated reflectivity measurements of ZnOSe alloys are used to demonstrate a splitting of the valence band due to the band anticrossing interaction between localized Se states and the extended valence band states of the host ZnO matrix. A strong multiband emission associated with optical transitions from the conduction band to lower E− and upper E+ valence subbands has been observed at room temperature. The composition dependence of the optical transition energies is well explained by the electronic band structure calculated using the kp method combined with the band anticrossing model. The observation of the multiband emission is possible because of relatively long recombination lifetimes. Longer than 1 ns lifetimes for holes photoexcited to the lower valence subband offer a potential of using the alloy as an intermediate band semiconductor for solar power conversion applications.

Valence-band offsets in strained SiGeSn/Si layers with different tin contents

Admittance spectroscopy is used to study hole states in Si0.7–y Ge0.3Sn y /Si quantum wells in the tin content range y = 0.04–0.1. It is found that the hole binding energy increases with tin content. The hole size-quantization energies in structures containing a pseudomorphic Si0.7–y Ge0.3Sn y layer in the Si matrix are determined using the 6-band kp method. The valence-band offset at the Si0.7–y Ge0.3Sn y heterointerface is determined by combining the numerical calculation results and experimental data. It is found that the dependence of the experimental values of the valence-band offsets between pseudomorphic Si0.7–y Ge0.3Sn y layers and Si on the tin content is described by the expression ΔE V exp = (0.21 ± 0.01) + (3.35 ± 7.8 × 10–4)y eV.

Scattering of electromagnetic plane wave from a perfect electric conducting strip located in topological insulator medium

In this article, scattering from a perfectly electric conducting strip located in an infinitely extended topological insulator (IT) medium is investigated using the Kobayashi potential method. For solving mixed boundary value problem, KP method is a fast and semi-analytical technique. In this method, edge conditions and boundary conditions are incorporated simultaneously. The scattered field is calculated from the strip geometry embedded in IT medium. The far zone scattered field is investigated with respect to different parameters of the geometry, i.e. topological parameter of the IT medium, size of the strip etc. It has been observed that the scattered field can be enhanced by increasing topological parameter of the IT medium. On the other hand, size of strip, permittivity of IT medium may also be used to enhance the main lobe of the scattering width/scattered field.

Electron states in a double quantum dot with broken axial symmetry

We study theoretically the electron states in a system of two vertically stacked quantum dots. We investigate the influence of the geometrical symmetry breaking (caused by the displacement as well as the ellipticity of the dots) on the electron states. Our modeling is based on the 8-band kp method. We show that the absence of axial symmetry of the system leads to a coupling of the s state from one dot with the p and d states from the other. Our findings indicate, that this coupling can produce a strong energy splitting at resonance (on the order of several meV) in the case of closely spaced quantum dots. Furthermore, we show that in the presence of a piezoelectric field, the direction of the displacement plays an important role in the character of the coupling.

微型铷原子钟专用795 nm垂直腔表面发射激光器

For the special requirements of the exciting source of a 87Rb based atomic clock for the miniaturization and high temperature conditions, a 795 nm Vertical Cavity Surface Emitting Laser(VCSEL)corresponding to the Rb atom energy level transition was designed and fabricated. Firstly, the energy levels and material gains of the InAlGaAs/AlGaAs Multiple Quantum Wells (MQWs) were calculated by the kp method to optimize the compositions and thicknesses of the quantum wells. Then, a Distributed Bragg Reflectors(DBRs) at 795 nm were designed and their reflection characteristics, longitudinal optical fields and averaged doping profiles were calculated and optimized using a one-dimensional transfer matrix method. Finally, the epitaxial structure of the 795 nm VCSEL with optimized MQWs and DBRs were grown on a GaAs substrate by Metal Organic Vapor Phase Epitaxy (MOVPE) and the oxide-confined 795 nm top-emitting VCSELs with unclosed-mesa structures were fabricated and characterized. Experimental results indicate that the packaged VCSELs can keep lasing under a cw current from 25 C to 85 C with power decreasing from 17 mW to 1.8 mW, the far field profiles are circular with a divergence angle of 15 and the temperature-shift of the lasing wavelength is 0.064 nm/C. Moreover, the lasing wavelength moves to the wavelength required by 87Rb atoms at an ambient temperature of 52 C and a current of 100 mA. The 795 nm VCSELs satisfy the basic requirements of 87Rb based miniaturized atom clocks for stable operation in a special wavelength and high-temperatures.

Eficiência de métodos para o cálculo de coeficientes do tanque classe A na estimativa da evapotranspiração de referência

Os valores do coeficiente do tanque classe A (Kp) podem ser determinados por vários métodos. A maioria baseia-se na velocidade do vento, umidade relativa e condições e extensão da bordadura que circunda o tanque. Este estudo objetivou avaliar o desempenho de métodos de estimativa do Kp e o uso de um Kp médio e constante (0,70), na avaliação da evapotranspiração de referência (ET0), sob condições de Cerrado, em Santo Antônio de Goiás (GO). Os métodos foram avaliados nos períodos anual, seco e chuvoso. As ET0 obtidas por meio da evaporação do tanque, multiplicadas pelos valores de Kp estimados com os métodos de Doorenbos &amp; Pruitt (1977), Cuenca (1989), Snyder (1992), Pereira et al. (1995) e Allen et al. (1998), foram comparadas com a ET0 estimada pelo modelo de Penman-Montheit. Foram determinados os coeficientes de determinação (r²), correlação (r), concordância (d) de Willmott e de desempenho (c) e, também, os erros médios e máximos absolutos. Para as condições climáticas nas quais se realizou o trabalho, o melhor método de determinação do Kp, para estimativa da ET0 no período anual, foi o de Pereira et al. (1995). Para o período seco, destacou-se o método proposto por Cuenca (1989) e, para o período chuvoso, todos os métodos apresentaram baixos desempenhos, sendo o de Pereira et al. (1995) o mais eficiente. A adoção de um Kp fixo e constante de 0,70 resultou em bom desempenho, sendo uma opção bastante prática, porém, faz-se necessária a sua determinação no local onde será aplicado.

SCATTERING OF ELECTROMAGNETIC SPHERICAL WAVE BY A PERFECTLY CONDUCTING DISK

The scattering of electromagnetic spherical wave by a perfectly conducting circular disk is studied by using the method of Kobayashi Potential (abbreviated as KP method). The formulation of the problem yields the dual integral equations (DIE). The spherical wave is produced by an arbitrarily oriented dipole. The unknowns are the induced surface current (or magnetic fleld) and the tangential components of the electric fleld on the disk. The solution for the surface current is expanded in terms of a set of functions which satisfy one of a pair (equations for the magnetic fleld) of Maxwell equations and the required edge condition on the surface of the disk. At this stage we have used the vector Hankel transform. Applying the projection solves the rest of the pair of equations. Thus the problem reduces to the matrix equations for the expansion coe-cients. The matrix elements are given in terms of the inflnite integrals with a single variable and these may be transformed into inflnite series that are convenient for numerical computation. The far fleld patterns of the scattered wave are computed and compared with those computed based on the physical optics approximation. The agreement between them is fairly good.

SCATTERING OF AN ARBITRARILY ORIENTED DIPOLE FIELD BY A CIRCULAR DISK WITH SURFACE IMPEDANCE

The scattering of an arbitrarily oriented dipole fleld by a circular disk with surface impedance is investigated by using the method of Kobayashi Potential (KP method). The dual integral equations (DIE) are produced during formulation of the problem. The solution of the DIEs is constructed in terms of set of functions which satisfy the boundary conditions as well as required edge conditions. At this stage, we applied the discontinuous properties of Weber Schafheitlins integral and vector Hankel transform. After applying the projection, the resulting expressions are reduced to the matrix equations for the expansion coe-cients. The matrix elements are given in terms of the inflnite integrals. The far fleld patterns for the scattered wave are computed for difierent incident angles, disk sizes and surface impedances for ‰-, `- and z-directed dipole fleld excitation. To validate the results we have obtained the results based on the physical optics approximation and their comparison shows that they quite reasonably match.