Articoli di riviste: "Semi-parametric single index"

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Masten, Arjana Brezigar, e Igor Masten. "Predicting Bankruptcy with Semi-Parametric Single-Index Model". Economic Research-Ekonomska Istraživanja 25, n. 1 (gennaio 2012): 99–108. http://dx.doi.org/10.1080/1331677x.2012.11517497.

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Zhou, Xiao-Hua, e Hua Liang. "Semi-parametric single-index two-part regression models". Computational Statistics & Data Analysis 50, n. 5 (marzo 2006): 1378–90. http://dx.doi.org/10.1016/j.csda.2004.12.001.

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Xia, Yingcun, e Wolfgang Härdle. "Semi-parametric estimation of partially linear single-index models". Journal of Multivariate Analysis 97, n. 5 (maggio 2006): 1162–84. http://dx.doi.org/10.1016/j.jmva.2005.11.005.

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Zhou, Weilun, Jiti Gao, David Harris e Hsein Kew. "Semi-parametric single-index predictive regression models with cointegrated regressors". Journal of Econometrics 238, n. 1 (gennaio 2024): 105577. http://dx.doi.org/10.1016/j.jeconom.2023.105577.

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Birke, Melanie, Sebastien Van Bellegem e Ingrid Van Keilegom. "Semi-parametric Estimation in a Single-index Model with Endogenous Variables". Scandinavian Journal of Statistics 44, n. 1 (20 ottobre 2016): 168–91. http://dx.doi.org/10.1111/sjos.12247.

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Ahmed, Huda Yahya, e Munaf Yousif Hmood. "Comparison of Some Semi-parametric Methods in Partial Linear Single-Index Model". Journal of Economics and Administrative Sciences 27, n. 130 (1 dicembre 2021): 170–84. http://dx.doi.org/10.33095/jeas.v27i130.2207.

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The research dealt with a comparative study between some semi-parametric estimation methods to the Partial linear Single Index Model using simulation. There are two approaches to model estimation two-stage procedure and MADE to estimate this model. Simulations were used to study the finite sample performance of estimating methods based on different Single Index models, error variances, and different sample sizes , and the mean average squared errors were used as a comparison criterion between the methods were used. The results showed a preference for the two-stage procedure depending on all the cases that were used

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Alahiane, Mohamed, Idir Ouassou, Mustapha Rachdi e Philippe Vieu. "High-Dimensional Statistics: Non-Parametric Generalized Functional Partially Linear Single-Index Model". Mathematics 10, n. 15 (30 luglio 2022): 2704. http://dx.doi.org/10.3390/math10152704.

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We study the non-parametric estimation of partially linear generalized single-index functional models, where the systematic component of the model has a flexible functional semi-parametric form with a general link function. We suggest an efficient and practical approach to estimate (I) the single-index link function, (II) the single-index coefficients as well as (III) the non-parametric functional component of the model. The estimation procedure is developed by applying quasi-likelihood, polynomial splines and kernel smoothings. We then derive the asymptotic properties, with rates, of the estimators of each component of the model. Their asymptotic normality is also established. By making use of the splines approximation and the Fisher scoring algorithm, we show that our approach has numerical advantages in terms of the practical efficiency and the computational stability. A computational study on data is provided to illustrate the good practical behavior of our methodology.

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Kadiri, Nadia, Sanaà Dounya Mekki e Abbes Rabhi. "Single Functional Index Quantile Regression for Functional Data with Missing Data at Random". Econometrics 27, n. 3 (2023): 1–19. http://dx.doi.org/10.15611/eada.2023.3.01.

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The primary goal of this research was to estimate the quantile of a conditional distribution using a semi-parametric approach in the presence of randomly missing data, where the predictor variable belongs to a semi-metric space. The authors assumed a single index structure to link the explanatory and response variable. First, a kernel estimator was proposed for the conditional distribution function, assuming that the data were selected from a stationary process with missing data at random (MAR). By imposing certain general conditions, the study established the model’s uniform almost complete consistencies with convergence rates.

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Feng, Guohua, Bin Peng, Liangjun Su e Thomas Tao Yang. "Semi-parametric single-index panel data models with interactive fixed effects: Theory and practice". Journal of Econometrics 212, n. 2 (ottobre 2019): 607–22. http://dx.doi.org/10.1016/j.jeconom.2019.05.018.

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Chang, Chaojie. "Research on Two-stage Estimation of Partially Linear Single-index Model with Longitudinal Data". Academic Journal of Science and Technology 5, n. 1 (28 febbraio 2023): 112–15. http://dx.doi.org/10.54097/ajst.v5i1.5438.

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Partial linear single-index model is a kind of semi-parametric model with wide application. In this paper, we deal with the partial linear single-index model under longitudinal data. A "two-stage estimation method" without iteration by using local polynomial and bias correction generalized estimation equation is proposed. under some regularity conditions, the asymptotic properties of the connection function and unknown parameter estimator are investigated. Numerical simulation shows that the proposed method is robust.

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Zhao, Yong-hong, Yang Weng, Ning-qi Peng, Guang-bo Tang e Zheng-dong Liu. "Prediction of Mechanical Properties of Hot Rolled Strip by Using Semi-Parametric Single-Index Model". Journal of Iron and Steel Research International 20, n. 7 (luglio 2013): 9–15. http://dx.doi.org/10.1016/s1006-706x(13)60119-3.

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حمود, مناف يوسف, e طارق عزيز صالح. ""compared some of penalized methods in analysis the semi- parametric single index model with practical application"". Journal of Economics and Administrative Sciences 22, n. 90 (1 luglio 2016): 407. http://dx.doi.org/10.33095/jeas.v22i90.516.

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المستخلص قي هدف هذا البحث تم أستعمال بعض الطرائق شبه المعلميه المعتمدة على دوال جزاء مختلفة من ضمنها الطرائق المقترحة من قبل الباحث اذ تعمل هذه الطرائق على تقدير وأختيار المتغيرات المعنوية لانموذج المؤشر الواحد شبه المعلمي في آن واحد منها (طريقة-SCAD-NPLS, الطريقة المقترحة الاولى SCAD-MAVE) ) والطريقة المقترحة الثانية (ALASSO-MAVE)) إذ تم أستعمال أجراء نوعين من الدراسات التطبيقية , الأجراء الأول أستعمل فيه أسلوب المحاكاة للمقارنة بين طرائق التقدير المدروسة ولمختلف تجارب المحاكاة والتعرف على أفضل طريقة بالأعتماد على معايير المقارنة (متوسط مربعات الخطأ (MSE) ومعدل متوسط مربعات الخطأ((AMSE ). والأجراء الثاني أستعمل فيه البيانات الحقيقية للتحقق من أداء الطرائق شبه المعلميه في الواقع العملي, وتم التوصل الى ان افضل طريقة لتقدير واختيار المتغير لانموذج المؤشر الواحد شبه العلمي هي الطريقة المقترحة الثانية (MAVE-ALASSO) لكل من تجارب المحاكاة لانموذج المؤشر الواحد شبه المعلمي الاول والبيانات الحقيقية.

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Ali, Fayyadh, e Tareq Salih. "Analysis of semi-parametric single-index models by using MAVE-method based on some kernel functions". International Journal of Advanced Statistics and Probability 5, n. 1 (11 maggio 2017): 37. http://dx.doi.org/10.14419/ijasp.v5i1.7258.

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In this paper, we used many forms of kernel functions with minimum average variance estimation (MAVE) method [Xia2002] we called the proposed methods (MAVE-Biweight), (MAVE-Epanechnikov ) and .(MAVE-Gaussian ) for estimation the parameters and the link function of the single – index model (SIM) comparing with other methods of estimation . to evaluate the performing of the various methods s simulation and a real data have been used, conclusions showed that the (MAVE- Gaussian) method in this paper gave better results compared with other methods depending on the mean squared error (MSE) and mean Absolute error (MAE) criterion for comparison.

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Brentnall, Adam R., e Jack Cuzick. "Use of the concordance index for predictors of censored survival data". Statistical Methods in Medical Research 27, n. 8 (29 dicembre 2016): 2359–73. http://dx.doi.org/10.1177/0962280216680245.

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The concordance index is often used to measure how well a biomarker predicts the time to an event. Estimators of the concordance index for predictors of right-censored data are reviewed, including those based on censored pairs, inverse probability weighting and a proportional-hazards model. Predictive and prognostic biomarkers often lose strength with time, and in this case the aforementioned statistics depend on the length of follow up. A semi-parametric estimator of the concordance index is developed that accommodates converging hazards through a single parameter in a Pareto model. Concordance index estimators are assessed through simulations, which demonstrate substantial bias of classical censored-pairs and proportional-hazards model estimators. Prognostic biomarkers in a cohort of women diagnosed with breast cancer are evaluated using new and classical estimators of the concordance index.

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Niño-Mora, José. "A Fast-Pivoting Algorithm for Whittle’s Restless Bandit Index". Mathematics 8, n. 12 (15 dicembre 2020): 2226. http://dx.doi.org/10.3390/math8122226.

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The Whittle index for restless bandits (two-action semi-Markov decision processes) provides an intuitively appealing optimal policy for controlling a single generic project that can be active (engaged) or passive (rested) at each decision epoch, and which can change state while passive. It further provides a practical heuristic priority-index policy for the computationally intractable multi-armed restless bandit problem, which has been widely applied over the last three decades in multifarious settings, yet mostly restricted to project models with a one-dimensional state. This is due in part to the difficulty of establishing indexability (existence of the index) and of computing the index for projects with large state spaces. This paper draws on the author’s prior results on sufficient indexability conditions and an adaptive-greedy algorithmic scheme for restless bandits to obtain a new fast-pivoting algorithm that computes the n Whittle index values of an n-state restless bandit by performing, after an initialization stage, n steps that entail (2/3)n3+O(n2) arithmetic operations. This algorithm also draws on the parametric simplex method, and is based on elucidating the pattern of parametric simplex tableaux, which allows to exploit special structure to substantially simplify and reduce the complexity of simplex pivoting steps. A numerical study demonstrates substantial runtime speed-ups versus alternative algorithms.

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Allal, Anis, Abdassamad Dib e Abbes Rabhi. "Central Limit Theorem for Conditional Mode in the Single Functional Index Model with Data Missing at Random". Econometrics 28, n. 1 (2024): 39–60. http://dx.doi.org/10.15611/eada.2024.1.04.

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This paper concentrates on nonparametrically estimating the conditional density function and conditional mode within the single functional index model for independent data, particularly when the variable of interest is affected by randomly missing data. This involves a semi-parametric single model structure and a censoring process on the variables. The estimator’s consistency (with rates) in a variety of situations, such as the framework of the single functional index model (SFIM) under the assumption of independent and identically distributed (i.i.d) data with randomly missing entries, as well as its performance under the assumption that the covariate is functional, are the main areas of focus. For this model, the nearly almost complete uniform convergence and rate of convergence are established. The rates of convergence highlight the critical part that the probability of concentration play in the law of the explanatory functional variable. Additionally, we establish the asymptotic normality of the derived estimators proposed under specific mild conditions, relying on standard assumptions in Functional Data Analysis (FDA) for the proofs. Finally, we explore the practical application of our findings in constructing confidence intervals for our estimators. The rates of convergence highlight the critical part that the probability of concentration play in the law of the explanatory functional variable.

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Rezapour, Mahdi, e Khaled Ksaibati. "Semi and Nonparametric Conditional Probability Density, a Case Study of Pedestrian Crashes". Open Transportation Journal 15, n. 1 (31 dicembre 2021): 280–88. http://dx.doi.org/10.2174/1874447802115010280.

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Background: Kernel-based methods have gained popularity as employed model residual’s distribution might not be defined by any classical parametric distribution. Kernel-based method has been extended to estimate conditional densities instead of conditional distributions when data incorporate both discrete and continuous attributes. The method often has been based on smoothing parameters to use optimal values for various attributes. Thus, in case of an explanatory variable being independent of the dependent variable, that attribute would be dropped in the nonparametric method by assigning a large smoothing parameter, giving them uniform distributions so their variances to the model’s variance would be minimal. Objectives: The objective of this study was to identify factors to the severity of pedestrian crashes based on an unbiased method. Especially, this study was conducted to evaluate the applicability of kernel-based techniques of semi- and nonparametric methods on the crash dataset by means of confusion techniques. Methods: In this study, two non- and semi-parametric kernel-based methods were implemented to model the severity of pedestrian crashes. The estimation of the semi-parametric densities is based on the adoptive local smoothing and maximization of the quasi-likelihood function, which is similar somehow to the likelihood of the binary logit model. On the other hand, the nonparametric method is based on the selection of optimal smoothing parameters in estimation of the conditional probability density function to minimize mean integrated squared error (MISE). The performances of those models are evaluated by their prediction power. To have a benchmark for comparison, the standard logistic regression was also employed. Although those methods have been employed in other fields, this is one of the earliest studies that employed those techniques in the context of traffic safety. Results: The results highlighted that the nonparametric kernel-based method outperforms the semi-parametric (single-index model) and the standard logit model based on the confusion matrices. To have a vision about the bandwidth selection method for removal of the irrelevant attributes in nonparametric approach, we added some noisy predictors to the models and a comparison was made. Extensive discussion has been made in the content of this study regarding the methodological approach of the models. Conclusion: To summarize, alcohol and drug involvement, driving on non-level grade, and bad lighting conditions are some of the factors that increase the likelihood of pedestrian crash severity. This is one of the earliest studies that implemented the methods in the context of transportation problems. The nonparametric method is especially recommended to be used in the field of traffic safety when there are uncertainties regarding the importance of predictors as the technique would automatically drop unimportant predictors.

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يوسف حمود, مناف, e يقين خليل برهان. "مقارنة بين طرائق تقدير انموذج دالة التحويل اللامعلمية وشبه المعلمية في السلاسل الزمنية باستعمال المحاكاة"A Comparison of Estimation Methods for Nonparametric and Semiparametric Transfer Function Models in Time Series Using Simulation"". Journal of Economics and Administrative Sciences 24, n. 106 (28 ottobre 2024): 375–91. http://dx.doi.org/10.33095/t7hd5c73.

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The transfer function model the basic concepts in the time series. This model is used in the case of multivariate time series. As for the design of this model, it depends on the available data in the time series and other information in the series so when the representation of the transfer function model depends on the representation of the data In this research, the transfer function has been estimated using the style nonparametric represented in two method local linear regression and cubic smoothing spline method The method of semi-parametric represented use semiparametric single index model, With four proposals, , That the goal of this research is comparing the capabilities of the above mentioned method using simulation at sample sizes (n = 100,150,200) as it found that the estimated proposed( C.S.S-L.S.I) is the best among the studied capabilities. Key terms of research: transfer function , local linear regression , cubic smoothing spline, semiparametric single index model يعد أنموذج دالة التحويل من المفاهيم الاساسية في السلاسل الزمنية اذ يتعامل مع السلسلة الزمنية المتعددة المتغيرات, اما بالنسبة الى تصميم هذا الانموذج فانه يعتمد على البيانات المتاحة في السلسلة الزمنية وعلى المعلومات الاخرى في السلسلة لذلك عند تمثيل إنموذج دالة التحويل يعتمد على تمثيل البيانات ودقة المعلومات المتاحة واستعمال هذه المعلومات في النموذجة, في هذا البحث تم تقدير دالة التحويل باستعمال الاسلوب اللامعلمي المتمثل بطريقتين الانحدار الخطي الموضعي وطريقة الشريحة التمهيدية التكعيبية والأسلوب شبه المعلمي متمثلا بانموذج احادي المؤشر شبه المعلمي مع مقترحين استعمال مؤشر احادي معلمي خطي مع مقدري انحدار الخطي الموضعي والشريحة التمهيدية التكعيبية, ان هدف هذا البحث يتمثل بمقارنة بين المقدرات المذكورة انفا باستعمال اسلوب المحاكاة و عند حجوم عينات(n=100,150,200) اظهرت النتائج التي تم التوصل اليها ان المقدر المقترح C.S.S-L.S.I) ) هو الافضل من بين المقدرات المدروسة لمعظم حجوم العينات المدروسة .

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Vera Recio, Carlos Christian, Jessica Corredor, Elissa Dodd-Eaton, Angelica M. Gutierrez-Barrera, Najat C. Daw, Banu Arun e Wenyi Wang. "Identification and characterization of de novo TP53 mutation carriers in Li-Fraumeni syndrome families: A single institution experience." Journal of Clinical Oncology 39, n. 15_suppl (20 maggio 2021): 10538. http://dx.doi.org/10.1200/jco.2021.39.15_suppl.10538.

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10538 Background: Li-Fraumeni syndrome (LFS) is an inherited cancer syndrome mainly caused by a deleterious mutation in TP53. An estimated 48% of LFS patients present due to a deleterious de novo mutation (DNM) in TP53. The knowledge of DNM status, DNM or familial mutation (FM), of an LFS patient requires genetic testing of both parents which is often inaccessible, making de novo LFS patients an understudied population. Famdenovo.TP53 is a Mendelian Risk prediction model used to predict DNM status of TP53 mutation carriers based on the cancer-family history and several input genetic parameters, including disease-gene penetrance. The good predictive performance of Famdenovo.TP53 was demonstrated using data collected from four historical US cohorts. We hypothesize that by incorporating penetrance estimates that are specific for different types of cancers diagnosed in family members, we can develop a model with further improved calibration, accuracy and prediction. Methods: We present Famdenovo.CS, which uses cancer-specific penetrance estimates that were derived previously using a Bayesian semi-parametric competing risk model, to calculate the DNM probability. We use our model to analyze 101 families recently collected from the Clinical Cancer Genetic program at MD Anderson Cancer Center (CCG-TP53) that includes 20 families with known DNM status and 81 families with unknown DNM status. We used the concordance index (AUC), observed:expected ratios (OE) and Brier score (BS) to measure our model’s discrimination, calibration and accuracy, respectively. We estimate the proportion of probands that present a DNM and compare DNM to FM carriers in several areas including: cancer types diagnosed, age at diagnosis, number of primary cancers diagnosed, sex, amino acid change caused by mutation in TP53. Results: Famdenovo.CS showed equally good discrimination and calibration performance to Famdenovo.TP53, while improving the overall accuracy, demonstrated by a decrease in the Brier score of -0.09 (95% CI: [-0.02, -0.19]). Of the 101 probands in the CCG-TP53 cohort, we predict 39 to be DNMs and 62 to be FMs. The cancer types and ages of diagnosis observed in FMs and DNMs are similarly distributed. Conclusions: Famdenovo.CS shows improved model accuracy in the CCG cohort. DNMs in TP53 are a prevalent cause of LFS and we did not find differences in the clinical characteristics of DNM and FM carriers. Our model allows for a systematic identification and characterization of TP53 DNM carriers.

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Cannon-Noren, Harry, e Richard Page. "Do lower limb kinetic and kinematic differences in drop jump landings persist when players have returned to sport following knee ligamentous injuries?" Graduate Journal of Sports Science, Coaching, Management, & Rehabilitation 1, n. 3 (7 giugno 2024): 42. http://dx.doi.org/10.19164/gjsscmr.v1i3.1525.

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Knee injuries (KI) are identified as one of the most burdensome lower limb injuries in football with long and complicated rehabilitation and high re-injury risk. Current research often describes technique deficits being present upon RTS, often being a result of poor return to sport (RTS) testing procedures. More recently, research has advocated the use of single leg vertical jump assessments, due to the specificity of the movement to injury mechanisms and the ability to consider different phases of the task to inform practitioners of joint contributions to the propulsion and landing phases. The aim of this research is to identify whether these functional deficits exist 12-24 months post RTS authorisation, to help inform future RTS in applied practice. Twenty-four semi-professional male footballers (mean ± SD: age 25 ± 4 years; stature 182 ± 7 cm; body mass 80 ± 8 kg) were recruited into a previously injured and a control group. Participants completed 5 repetitions of single leg drop jump (SLDJ). Jump height, ground contact time, reactive strength index, peak moments, angles and power contributions for the hip, knee and ankle were measured using Qualisys Track Manager then exported to Visual 3D. This study was approved by the Edge Hill University Ethics Committee. No significant findings were identified for landing one however, during the propulsion phase there was a difference between groups (P = 0.026, d=1.14) for knee flexion at take-off. Most differences were identified during landing two bilaterally in both groups. Within the injured group, differences were identified for peak hip (P = 0.011, d = 0.028) and knee powers (P < 0.001, d = 1.269), hip (P < 0.001, d = 1.924) and knee power contribution % (P < 0.001, d = 1.269). No differences were identified for the performance measures or through performing statistical parametric mapping for hip and knee powers for all three phases. Joint coupling analysis was conducted for the total ground contact time amalgamating the landing and propulsion phase, this was analysed as Hip-Knee, Hip-Ankle and Knee-Ankle, with significant findings in Hip-Knee and Hip-ankle. Both groups elicited bilateral differences however, no differences between the injured limb and dominant control limb were identified. To better apply this form of analysis to RTS testing, functional movements such should be undertaken when athletes are injury free to provide baseline measurements to refer to if undertaking rehabilitation from KI. Likewise, the current study identified that joint contributions could be identified in a more applied setting using the range of motion data from each joint.

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Goel, Sanjay, Abdissa Negassa e Ana Acuna-Villaorduna. "The comparative effectiveness of biologic agents among non-hispanic black (NHB) patients with metastatic colorectal cancer (mCRC): Preliminary results of a SEER-medicare analysis." Journal of Clinical Oncology 38, n. 15_suppl (20 maggio 2020): e19059-e19059. http://dx.doi.org/10.1200/jco.2020.38.15_suppl.e19059.

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e19059 Background: Biologic agents (bevacizumab, cetuximab, panitumumab) have improved the overall survival (OS) of patients with mCRC. However, clinical trials are plagued by low representation of NHB patients, and a disproportionately high (>90%) accrual of non-Hispanic whites (NHW). As a result, the real world benefit among NHB patients in unknown. Comparative effectiveness research is an approach for effectively addressing this drawback. Methods: Utilizing the SEER-Medicare linked database, we identified 5,728 patients with mCRC diagnosed between 2004 and 2011 who received chemotherapy (CT; oxaliplatin, irinotecan, 5-FU, capecitabine) alone or chemotherapy with a biologic agent (CBT). OS was examined using the Kaplan-Meier method and a weighted semi-parametric accelerated failure time model. A propensity score model approach was undertaken to further account for potential treatment selection bias. Results: Overall, 88% were NHW and 12% NHB patients. The median age at diagnosis was 73 and 70 years and exposure to biologics was 71.2% and 71.4%, respectively. NHB patients had more women, were single, had lower median incomes, better differentiated tumors, less rectal primary cancers, more right sided tumors, and a worse Charleson co morbidity index. There was no difference in the receipt of 1 (72%) vs > 2 (28%) lines of therapy. The median OS was 11 and 12 months (m) in the CT-alone group, and 21 and 22 m in CBT group, among NHW and NHB, respectively. Based on an unadjusted analysis, receipt of biologics, younger age, left sided primary, well/moderate differentiation, being married, more lines of CT, and lower prevalence of co-morbidity were associated with improved OS. We also performed multiple imputations to properly account for the missing data. Among NHW, median OS was 21 vs 11 m in the CBT and CT groups, respectively (effect 1.47, 95% CI 1.36-1.60, p = 0.0000). Among NHB, median OS was 22 vs 12 m in the CBT and CT groups, respectively (effect 1.48, 95% CI 1.23-1.88, p = 0.0000). All comparisons maintained significance when adjusted for multiple comparisons. We found no interaction between biologics and race (p = 0.8743). On subgroup analysis, those patients receiving both classes of biologics (anti EGFR and anti VEGF) had the best outcome. Conclusions: In this cohort of older patients, CBT was associated with longer survival, regardless of race. Clinicians should offer CBT therapy to all patients to maximize their clinical benefit, factoring in clinical variables, but not their race.

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Nunes Fortunato, Cibelly, Ana Cristina Oliveira e Silva, Micheline Da Silveira Mendes, Sérgio Vital Da Silva Júnior, Allan Batista Silva e Maria Eliane Moreira Freire. "Qualidade de vida de pessoas com hanseníase atendidas em um hospital de referência, Paraíba-Brasil". Enfermería Global 18, n. 4 (16 settembre 2019): 119–58. http://dx.doi.org/10.6018/eglobal.18.4.342601.

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Objective: Evaluate the degree of impairment of the quality of life of people with Hansen’s disease, according to social demographic and clinical variablesMethod: Descriptive, transversal, quantitative study, involving 45 patients from a reference hospital located in João Pessoa, Paraíba, Brazil. For obtaining data, interviews were performed based on a semi-structured questionnaire, including social demographic and clinic variables of the participants; to evaluate their life quality the instrument Dermatology Life Quality Index, was used, after approval in the Committee of Ethics in Research of the Federal University of Paraíba. In the data analysis, the non-parametric Test of the Chi-square of Pearson was used with level of significance of 5% (p<0,05), being used the Yates correction continuity, when necessary.Results: It is highlighted a prevalence of male, brown, single, aged 18 to 40 individuals, with family income lower than three minimum salaries and low schooling. From this total, 88,9% presented the clinical multibacillary form of the Hansen’s disease and 60% of them, with level of impairment of quality of life varying between moderate and very serious, according to scores of the instrument used.Conclusion: It is reassured the important impact of the Hansen’s disease in the quality of life of their carriers, as indicated by the high scores obtained in the application of the DLQI. Objetivo: Evaluar el grado de deterioro de la calidad de vida de las personas con enfermedad de Hansen, de acuerdo con las variables sociodemográficas y clínicasMétodo: Estudio descriptivo, transversal, cuantitativo, que involucró a 45 pacientes de un hospital de referencia en João Pessoa, Paraíba, Brasil. Para la obtención de datos, las entrevistas se realizaron a partir de un cuestionario semiestructurado que incluyó las variables sociodemográficas y clínicas de los participantes; para evaluar su calidad de vida se utilizó el instrumento Dermatology Life Quality Index, luego de su aprobación en el Comité de Ética en Investigación de la Universidad Federal de Paraíba. En el análisis de los datos, se utilizó la Prueba no paramétrica del Qui-cuadrado de Pearson con un nivel de significación del 5% (p <0,05), usándose la continuidad de corrección de Yates, cuando fue necesario.Resultados: Se destaca la prevalencia de individuos varones, pardos, solteros, de entre 18 y 40 años, con ingresos familiares inferiores a tres salarios mínimos y baja escolaridad. De este total, el 88,9% presentó la forma clínica multibacilar de la enfermedad de Hansen y el 60% de ellos, con un nivel de deterioro de la calidad de vida que varía entre moderado y muy grave, según los puntajes del instrumento utilizado.Conclusión: Se confirma el importante impacto de la enfermedad de Hansen en la calidad de vida de sus portadores, como lo indican los altos puntajes obtenidos en la aplicación del DLQI. Objetivo: Avaliar o grau de comprometimento da qualidade de vida de pessoas com hanseníase, segundo variáveis sociodemográficas e clínicas. Método: Estudo descritivo, transversal, quantitativo, envolvendo 45 pacientes de um hospital de referência, localizado em João Pessoa, Paraíba, Brasil. Para obtenção dos dados, realizou-se entrevistas a partir de questionário semiestruturado, contemplando variáveis sociodemográficas e clínicas dos participantes; para avaliar sua qualidade de vida foi utilizado o instrumento Dermatology Life Quality Index, após aprovação do Comitê de Ética em Pesquisa da Universidade Federal da Paraíba. Na análise dos dados, utilizou-se o Teste não-paramétrico do Qui-quadrado de Pearson com nível de significância de 5% (p<0,05), sendo utilizado a Correção de Continuidade de Yates, quando necessário.Resultados: Evidencia-se uma prevalência dos indivíduos do sexo masculino, pardos, solteiros, com idade entre 18 e 40 anos, com renda familiar inferior a três salários mínimos e baixa escolaridade. Desse total, 88,9% apresentavam a forma clínica multibacilar da hanseníase e 60% deles, com grau de comprometimento da qualidade de vida vaiando de moderado a muito grave, segundo escores do instrumento utilizado.Conclusão: Reafirma-se o importante impacto da hanseníase na qualidade de vida de seus portadores, tal como indicado pelos altos escores obtidos na aplicação do DLQI.

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Forchini, Giovanni, e Raoul Theler. "Semi-parametric modelling of inefficiencies in stochastic frontier analysis". Journal of Productivity Analysis, 16 dicembre 2022. http://dx.doi.org/10.1007/s11123-022-00656-x.

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AbstractWe propose a novel penalized splines method to estimate a stochastic frontier model in which the frontier is linear and the inefficiency has a single index structure with unknown link function and a linear index. The approach is more flexible than the traditional methodology requiring a parametric link function and, at the same time, it does not incur the curse of dimensionality as a fully non-parametric approach. The procedure can be easily implemented using existing software. We give conditions for the model to be identified and provide some asymptotic results. We also use Monte Carlo simulations to show that the approach works well in finite samples in many situations when compared to the well specified maximum likelihood estimator. An application to the residential energy demand of US states is considered. In this case, the penalized splines approach estimates inefficiency functions that deviate substantially from those resulting from parametric maximum likelihood methods previously implemented.

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Chan, Lax, Laurent Delsol e Aldo Goia. "A link function specification test in the single functional index model". Advances in Data Analysis and Classification, 22 giugno 2023. http://dx.doi.org/10.1007/s11634-023-00545-7.

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AbstractIn this paper a test for specification in functional regression with scalar response that exploits semi-parametric principles is illustrated. Once the test statistics is defined, its asymptotic null distribution is derived under suitable conditions. The finite sample performances of the test are analyzed through a simulation study by using both the asymptotic p-value and some bootstrap approaches. To appreciate the potentialities of the method, an application to a spectrometric real dataset is performed.

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