Air Travel Choices in Multi-Airport Markets

We estimate a conditional logit model to measure the impact of airport and airline supply characteristics on the air travel choices of passengers departing from one of three San Francisco Bay area airports and arriving at one of four airports in greater Los Angeles in October 1995. Non-price characteristics like airport access time, airport delay, flight frequency, the availability of particular airport-airline combinations, and early arrival times are found to strongly affect choice probabilities. Marginal effects and counterfactual scenarios suggest that changes access in times affect travel choices more than changes in travel delays, and that the preferred airport differs by passenger type. In order to examine the robustness of the conditional logit model, we estimate a mixed logit model, and find that the results are similar. We attribute the similarity to our strictly defined travel market and to our distinction between leisure and business travelers, thus controlling for two important sources of consumer heterogeneity.Airports; Airlines; Air travel demand; Discrete choice

Competition, Innovation and Racing for Priority at the U.S. Patent and Trademark Office

The U.S. Patent and Trademark Office resolves patent priority disputes in patent interference cases. Using a random sample of cases declared between 1988 and 1994, we establish a connection between patent interferences and patent races, and then use the data to consider some key issues in dynamic competition and innovation. We look at the incidence and distribution of patent races by technology, evidence for strategic delay of innovation by incumbent firms, and evidence that patent races moderate incentives to delay. Our results have implications for patent policy in general and for evaluating the U.S. “first to invent†patent priority rule.Patent race, Patent interference, US Board of Patent Appeals and Interferences, Patent litigation; Innovation; Research and development

Sub-Arcsecond Near-Infrared Images of Massive Star Formation Region NGC 6334 V

We present high spatial resolution (0\farcs3) polarimetric images in the $H$ and $K$ bands and direct images in the $L'$ and $M'$ bands of the NGC 6334 V infrared nebulae. The images show complex structures including the multi-shells and various knots in the nebulae. The appearances and colors of the eastern and western nebulae differ considerably. Our polarization images also show differences between the illuminating sources of the nebulae: the eastern nebula is illuminated by a deeply embedded mid-infrared source, KDJ 4, and the western nebula by our newly detected near-infrared source, WN-A1. The degree of polarization of the nebulae is very large, up to 70% at $K$ and 60% at $H$, which is consistent with a single scattering of near-infrared radiation from each source at the walls of the mass outflows

Biosensing Techniques in Yeast: G-Protein Signaling and Protein-Protein Interaction Assays for Monitoring Ligand Stimulation and Oligomer Formation of Heterologous GPCRs

Guanine nucleotide-binding proteins (G-proteins) act as transducers of external stimuli for intracellular signaling, and control various cellular processes in cooperation with seven transmembrane G-protein-coupled receptors (GPCRs). Because GPCRs constitute the largest family of eukaryotic membrane proteins and enable the selective recognition of a diverse range of molecules (ligands), they are the major molecular targets in pharmaceutical and medicinal fields. In addition, GPCRs have been known to form heteromers as well as homomers, which may result in vast physiological diversity and provide opportunities for drug discovery. G-proteins and their signal transduction machinery are universally conserved in eukaryotes; thereby, the yeast Saccharomyces cerevisiae has been used to construct artificial in vivo GPCR biosensors. In this chapter, we focus on the yeast-based GPCR biosensors that can detect ligand stimulation and oligomer formation, and summarize their techniques using the G-protein signaling and protein-protein interaction assays

Competition, Innovation and Racing for Priority at the U.S. Patent and Trademark Office

When two inventors file patent applications with overlapping, or "interfering" claims, the U.S. patent rights are awarded to the applicant who establishes priority of invention. Patent interference cases are litigated at the U.S. Patent and Trademark Office's Board of Patent Appeals and Interferences. The cases offer a unique window into competition between firms in research and innovation. This paper analyzes a random sample of interferences to investigate the impact of patent policies on innovation strategies. Our results contribute to the policy debate over the appropriate scope of patents and the revision of the U.S. patent priority structure. We find that while interference cases are in general rare, they are highly concentrated among chemical and biomedical firms. Biotechnology patent applications are so likely to be subject to interference litigation that a question arises about their character: a high rate of interfering means that multiple researchers are chasing a large patent prize associated with a well-defined research topic. This in turn suggests that either the scope of biotechnology patents is too broad or the bar for obviousness has been set too low. Alternatively, the benefits of competition and patent racing to innovation are clear in the patent filing behavior of incumbent and challenger firms. Our empirical results suggest that incumbent firms delay filing patent applications relative to challengers, consistent with the hypothesis that incumbents attempt to delay the introduction of new technologies. But competition from an interference challenge leads incumbents to accelerate filing their patent applications, and thus both the commercialization of new technology and the diffusion of technological information. Strategic filing is exacerbated by the unique U.S. priority structure, which awards disputed patent rights to an inventor who proves that he or she is first-to-invent rather than first to file. Reforming the priority structure, a goal of current efforts to harmonize U.S. patent policies with other countries, has been controversial because of its alleged benefits to entrepreneurs. We find no evidence for the claim that the system benefits small firms or individual inventors over large organizations with patent filing expertise. Instead, we find that the system empowers incumbent firms who seek to delay filing their patent applications, knowing that if they lose the race to the patent office they can still obtain the intellectual property rights with a first-to-invent showing.

How Cervical Reconstruction Surgery Affects Global Spinal Alignment.

BACKGROUND:There have been no reports describing how cervical reconstruction surgery affects global spinal alignment (GSA). OBJECTIVE:To elucidate the effects of cervical reconstruction for GSA through a retrospective multicenter study. METHODS:Seventy-eight patients who underwent cervical reconstruction surgery for cervical kyphosis were divided into a Head-balanced group (n = 42) and a Trunk-balanced group (n = 36) according to the values of the C7 plumb line (PL). We also divided the patients into a cervical sagittal balanced group (CSB group, n = 18) and a cervical sagittal imbalanced group (CSI group, n = 60) based on the C2 PL-C7 PL distance. Various sagittal Cobb angles and the sagittal vertical axes were measured before and after surgery. RESULTS:Cervical alignment was improved to achieve occiput-trunk concordance (the distance between the center of gravity [COG] PL, which is considered the virtual gravity line of the entire body, and C7 PL < 30 mm) despite the location of COG PL and C7PL. A subsequent significant change in thoracolumbar alignment was observed in Head-balanced and CSI groups. However, no such significant change was observed in Trunk-balanced and CSB groups. We observed 1 case of transient and 1 case of residual neurological worsening. CONCLUSION:The primary goal of cervical reconstruction surgery is to achieve occiput-trunk concordance. Once it is achieved, subsequent thoracolumbar alignment changes occur as needed to harmonize GSA. Cervical reconstruction can restore both cervical deformity and GSA. However, surgeons must consider the risks and benefits in such challenging cases