209 research outputs found
Model Averaging by Cross-validation for Partially Linear Functional Additive Models
In this paper, we propose a model averaging approach for addressing model
uncertainty in the context of partial linear functional additive models. These
models are designed to describe the relation between a response and mixed-types
of predictors by incorporating both the parametric effect of scalar variables
and the additive effect of a functional variable. The proposed model averaging
scheme assigns weights to candidate models based on the minimization of a
multi-fold cross-validation criterion. Furthermore, we establish the asymptotic
optimality of the resulting estimator in terms of achieving the lowest possible
square prediction error loss under model misspecification. Extensive simulation
studies and an application to a near infrared spectra dataset are presented to
support and illustrate our method
Estimating optimal treatment regimes in survival contexts using an instrumental variable
In survival contexts, substantial literature exists on estimating optimal
treatment regimes, where treatments are assigned based on personal
characteristics for the purpose of maximizing the survival probability. These
methods assume that a set of covariates is sufficient to deconfound the
treatment-outcome relationship. Nevertheless, the assumption can be limiting in
observational studies or randomized trials in which noncompliance occurs. Thus,
we advance a novel approach for estimating the optimal treatment regime when
certain confounders are not observable and a binary instrumental variable is
available. Specifically, via a binary instrumental variable, we propose two
semiparametric estimators for the optimal treatment regime, one of which
possesses the desirable property of double robustness, by maximizing
Kaplan-Meier-like estimators within a pre-defined class of regimes. Because the
Kaplan-Meier-like estimators are jagged, we incorporate kernel smoothing
methods to enhance their performance. Under appropriate regularity conditions,
the asymptotic properties are rigorously established. Furthermore, the finite
sample performance is assessed through simulation studies. We exemplify our
method using data from the National Cancer Institute's (NCI) prostate, lung,
colorectal, and ovarian cancer screening trial
Current and Future Trends of Resource Misallocation in the Construction Industry: A Bibliometric Review with Grounded Theory
[EN] Resource misallocation (RM) refers to the existence of marginal output inequalities between different industries or companies in an economy. Prior studies of RM have mostly focused on effect analysis, construction industry structure upgrades, and organization management. However, these studies have been fragmented and unrelated. This paper analyzes the status quo, consequences, and emerging trends of RM research at the macroscopic level based on current problems and with the aim of exploring potential solutions. Drawing on grounded theory, a qualitative analysis using text-mining is used to analyze the characteristics of 124 RM-related papers. The results more comprehensively and systematically reveal that current RM research encompasses four major dimensions of sources and concepts, misallocation degree measurement and characterization, focused issues (field), and RM research deficiencies. Methods for measuring RM have also been developed from the simple proportional method to current mainstream methods (e.g., growth rate decomposition and variant substitution). We conclude that, in order for this discipline to thrive and effectively reduce RM, future research into RM should focus on core categories, especially the reform of market-oriented factors, transformation of government functions, construction industrial structure adjustment, and methods of income distribution. This systematic review provides a discipline oversight and uncovers necessary and potential research directionsThis research is supported by the National Social Science Fund projects (No. 20BJY010); National Social Science Fund Post-financing projects (No. 19FJYB017); Sichuan-Tibet Railway Major Fundamental Science Problems Special Fund (No. 71942006); List of Key Science and Technology Projects in China's Transportation Industry in 2018-International Science and Technology Cooperation Project (No. 2018-GH-006 and No. 2019-MS5-100); Emerging Engineering Education Research and Practice Project of Ministry of Education of China (No. E-GKRWJC20202914).Zhang, J.; Dong, F.; Ballesteros-PĂ©rez, P.; Li, H.; Skitmore, M. (2022). Current and Future Trends of Resource Misallocation in the Construction Industry: A Bibliometric Review with Grounded Theory. Buildings. 12(10):1-19. https://doi.org/10.3390/buildings12101731119121
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Combined Treatment with MEK and mTOR Inhibitors is Effective in In Vitro and In Vivo Models of Hepatocellular Carcinoma.
Background: Hepatocellular carcinoma (HCC) is the most common primary liver cancer histotype, characterized by high biological aggressiveness and scarce treatment options. Recently, we have established a clinically relevant murine HCC model by co-expressing activated forms of v-akt murine thymoma viral oncogene homolog (AKT) and oncogene c-mesenchymal-epithelial transition (c-Met) proto-oncogenes in the mouse liver via hydrodynamic tail vein injection (AKT/c-MET mice). Tumor cells from these mice demonstrated high activity of the AKT/ mammalian target of rapamycin (mTOR) and Ras/ Mitogen-activated protein kinase (MAPK) signaling cascades, two pathways frequently co-induced in human HCC. Methods: Here, we investigated the therapeutic efficacy of sorafenib, regorafenib, the MEK inhibitor PD901 as well as the pan-mTOR inhibitor MLN0128 in the AKT/c-Met preclinical HCC model. Results: In these mice, neither sorafenib nor regorafenib demonstrated any efficacy. In contrast, administration of PD901 inhibited cell cycle progression of HCC cells in vitro. Combined PD901 and MLN0128 administration resulted in a pronounced growth constraint of HCC cell lines. In vivo, treatment with PD901 or MLN0128 alone moderately slowed HCC growth in AKT/c-MET mice. Importantly, the simultaneous administration of the two drugs led to a stable disease with limited tumor progression in mice. Mechanistically, combined mitogen-activated extracellular signal-regulated kinase (MEK) and mTOR inhibition resulted in a stronger cell cycle inhibition and growth arrest both in vitro and in vivo. Conclusions: Our study indicates that combination of MEK and mTOR inhibitors might represent an effective therapeutic approach against human HCC
Developing a Revenue Sharing Method for an Operational Transfer-Operate-Transfer Project
The transfer-operate-transfer (TOT) project model is used widely as a commercial framework for public-private-partnerships to support provision of infrastructure and enable the delivery of services. However, operational delivery of such projects can encounter certain challenges, such as the need for improved revenue sharing between governmental and private partners. The purpose of this paper is to design a revenue sharing method (RSM) that satisfies the revenue-sharing forecast in the contract design stage and the realized revenue sharing in the contract execution period for an operational TOT project. This approach identifies the impact of external uncertainty and effort level as well as the input ratio on revenue sharing of participants, distributes and reasonably minimizes the project revenue uncertainty among the participants, and achieves an improved matching of the participants’ revenue sharing with their risk-sharing, resource input and effort level. The paper utilizes the fuzzy-payoffs Shapley value method for revenue distribution for an operational TOT project, where the fuzzy alliance and input ratio coefficient are adopted to gradually optimize the Shapley value and form the RSM of an operational TOT project. The RSM allows prediction of the revenue sharing of participations under uncertain conditions of project revenue and supports improved decision-making by participants
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