Estimation of conditional cumulative incidence functions under generalized semiparametric regression models with missing covariates,with application to analysis of biomarker correlates in vaccine trials

This article presents generalized semiparametric regression models for conditional cumulative incidence functions with competing risks data when covariates are missing by sampling design or happenstance. A doubly robust augmented inverse probability weighted (AIPW) complete-case approach to estimation and inference is investigated. This approach modifies IPW complete-case estimating equations by exploiting the key features in the relationship between the missing covariates and the phase-one data to improve efficiency. An iterative numerical procedure is derived to solve the nonlinear estimating equations. The asymptotic properties of the proposed estimators are established. A simulation study examining the finite-sample performances of the proposed estimators shows that the AIPW estimators are more efficient than the IPW estimators. The developed method is applied to the RV144 HIV-1 vaccine efficacy trial to investigate vaccine-induced IgG binding antibodies to HIV-1 as correlates of acquisition of HIV-1 infection while taking account of whether the HIV-1 sequences are near or far from the HIV-1 sequences represented in the vaccine construct.     

CREDIT CONSTRAINTS AND THE CYCLICALITY OF R&D INVESTMENT: EVIDENCE FROM FRANCE

We use a French firm‐level data set containing 13,000 firms over the period 1994–2004 to analyze the relationship between credit constraints and firms’ R&D behavior over the business cycle. Our main results can be summarized as follows: (i) R&D investment is countercyclical without credit constraints, but it becomes procyclical as firms face tighter credit constraints; (ii) this result is only observed for firms in sectors that depend more heavily upon external finance, or that are characterized by a low degree of asset tangibility; (iii) in more credit‐constrained firms, R&D investment plummets during recessions but does not increase proportionally during upturns.     

A New Multiperiod Multiple Traveling Salesman Problem with Heuristic and Application to a Scheduling Problem

A new multiperiod variation of the M-traveling salesman problem is introduced. The problem arises in efficient scheduling of optimal interviews among tour brokers and vendors at conventions of the tourism and travel industry. In classical traveling salesman problem vocabulary, a salesman is a tour broker at the convention and a city is a vendor's booth. In this problem, more than one salesman may be required to visit a city, but at most one salesman per time period can visit each city. The heuristic solution method presented is polynomial and is guaranteed to produce a nonconflicting set of salesmen's tours. The results of an implementation of the method for a recent convention are also reported.     

A MULTIATTRIBUTE DECISION-MAKING APPROACH TO THE SELECTION OF AN AUXILIARY DEVICE FOR ICEBREAKERS*

This paper describes the use of multiattribute decision making by the U.S. Coast Guard when choosing the most appropriate auxiliary device to use on an icebreaker. Five different missions of icebreakers are defined, and the objectives and attributes that describe the effectiveness of each auxiliary device in accomplishing these missions are established. For each geographical area of interest, the missions are weighted using the analytical hierarchy process. Also, group utilities are developed for attribute vectors in order to incorporate the judgments of different icebreaker operators.     

职务发明权属的模式反思与制度重构

我国职务发明制度肇生于计划经济时代，起初专利权由国家所有、单位持有的模式具有较为浓厚的时代特色。2000年《专利法》修改时将该规定删除，并建立了以法定权属规则为主，辅之以约定权属规则的“雇主主义”模式。尽管此次修法在一定程度上与我国的产业变革和技术革新需求相适配，但仍存在转化结构失调、激励机制失效和交易效率失衡等问题。横向考察国际视野下的职务发明权属制度可以发现，现有的雇主主义模式和雇员主义模式两种主要立法例均未臻完善。将专利权完全归属于雇主抑或是完全归属于雇员发明人，势必在二者之间产生职务发明权利分配不公的争议，进而导致雇主与雇员发明人之间的严重隔阂，从而抑制雇员发明人的创新活力或雇主的投资积极性。多数国家的做法是打破绝对的“雇主主义”和“雇员主义”立法路径，采取混合主义的立法模式。我国职务发明权属制度采取“雇主主义”模式是实现职务发明创造转化和运用的根本途径，但对于调动人的创新积极性增加财产总量仍存有不足之处。我国关于职务发明权属制度的改革应当着眼于三个方面：一是采取“执行任务”标准，限缩职务发明类型范围。首先，基于雇员发明人在劳动关系中的人身依附性，将“物质技术条件标准”排除出职...