Growing Apart: The Changing Firm-Size Wage Premium and Its Inequality Consequences

Wage inequality in the United States has risen dramatically over the past few decades, prompting scholars to develop a number of theoretical accounts for the upward trend. This study argues that large firms have been a prominent labor-market institution that mitigates inequality. By compensating their low- and middle-wage employees with a greater premium than their higher-wage counterparts, large U.S. firms reduced overall wage dispersion. Yet, broader changes to employment relations associated with the demise of internal labor markets and the emergence of alternative employment arrangements have undermined large firms’ role as an equalizing institution. Using data from the Current Population Survey and the Survey of Income and Program Participation, we find that in 1989, although all private-sector workers benefited from a firm-size wage premium, the premium was significantly higher for individuals at the lower end and middle of the wage distribution compared to those at the higher end. Between 1989 and 2014, the average firm-size wage premium declined markedly. The decline, however, was exclusive to those at the lower end and middle of the wage distribution, while there was no change for those at the higher end. As such, the uneven declines in the premium across the wage spectrum could account for about 20% of rising wage inequality during this period, suggesting that firms are of great importance to the study of rising inequality

Ab Externo Imaging of Human Episcleral Vessels Using Fiberoptic Confocal Laser Endomicroscopy

Purpose: There is a growing interest in targeting minimally invasive surgery devices to the aqueous outflow system to optimize treatment outcomes. However, methods to visualize functioning, large-caliber aqueous and episcleral veins in-vivo are lacking. This pilot study establishes an ex-vivo system to evaluate the use of a confocal laser microendoscope to noninvasively image episcleral vessels and quantify regional flow variation along the limbal circumference. Methods: A fiber-optic confocal laser endomicroscopy (CLE) system with lateral and axial resolution of 3.5 μm and 15 μm, respectively, was used on three porcine and four human eyes. Diluted fluorescein (0.04%) was injected into eyes kept under constant infusion. The microprobe was applied to the sclera 1 mm behind the limbus to acquire real-time video. Image acquisition was performed at 15-degree intervals along the limbal circumference to quantify regional flow variation in human eyes. Results: Vascular structures were visualized in whole human eyes without processing. Schlemm’s canal was visualized only after a scleral flap was created. Fluorescent signal intensity and vessel diameter variation were observed along the limbal circumference, with the inferior quadrant having a statistically higher fluorescein signal compared to the other quadrants in human eyes (P < 0.05). Conclusion: This study demonstrates for the first time that the fiber-optic CLE platform can visualize the episcleral vasculature with high resolution ex-vivo with minimal tissue manipulation. Intravascular signal intensities and vessel diameters were acquired in real-time; such information can help select target areas for minimally invasive glaucoma surgery (MIGS) to achieve greater intraocular pressure reduction

Sampled in Pairs and Driven by Text: A New Graph Embedding Framework

In graphs with rich texts, incorporating textual information with structural information would benefit constructing expressive graph embeddings. Among various graph embedding models, random walk (RW)-based is one of the most popular and successful groups. However, it is challenged by two issues when applied on graphs with rich texts: (i) sampling efficiency: deriving from the training objective of RW-based models (e.g., DeepWalk and node2vec), we show that RW-based models are likely to generate large amounts of redundant training samples due to three main drawbacks. (ii) text utilization: these models have difficulty in dealing with zero-shot scenarios where graph embedding models have to infer graph structures directly from texts. To solve these problems, we propose a novel framework, namely Text-driven Graph Embedding with Pairs Sampling (TGE-PS). TGE-PS uses Pairs Sampling (PS) to improve the sampling strategy of RW, being able to reduce ~99% training samples while preserving competitive performance. TGE-PS uses Text-driven Graph Embedding (TGE), an inductive graph embedding approach, to generate node embeddings from texts. Since each node contains rich texts, TGE is able to generate high-quality embeddings and provide reasonable predictions on existence of links to unseen nodes. We evaluate TGE-PS on several real-world datasets, and experiment results demonstrate that TGE-PS produces state-of-the-art results on both traditional and zero-shot link prediction tasks.Comment: Accepted by WWW 2019 (The World Wide Web Conference. ACM, 2019

How Many Fenestrations Should I Make When Placing a Baerveldt Glaucoma Implant? A Laboratory Study

Purpose: This study investigates the effect of one versus two fenestrations on both fluid egress and opening pressure from a non-valved glaucoma implant. Methods: In this laboratory study, we used an in vitro closed system comprised of ligated silicone tubing connected to a fluid reservoir and manometer to simulate the tubing found in a Baerveldt glaucoma drainage implant. Fenestrations were created using an 8-0 Vicryl TG140-8 suture needle. Main outcome measures included volume of fluid egress and fenestration opening pressures, which were measured via micropipette and increasing pressure until fluid egress was observed. Results: No significant difference was observed in fluid egress between tubing with one versus two fenestrations at pressures ≤40 mmHg. At 50 mmHg, a statistically significant difference was observed in fluid egress between tubing with one versus two fenestrations (P < 0.05). The first fenestration opened at 10.5 ± 3.77 mmHg and the second fenestration opened at 28.83 ± 5.09 mmHg (average ± standard deviation). Conclusion: Our in vitro findings suggest there may exist a critical pressure >40 mmHg at which the second fenestration starts to play a significant role in fluid drainage. There may be no difference in the amount of fluid egress and effect on intraocular pressure between one or two tube fenestrations when preoperative intraocular pressure is ≤40 mmHg

Knowledge Modeling for Readiness Self-Assessment

Online readiness self-assessments are widely used in universities providing distant education, and they can help prospective students to understand the requirements and their readiness to study in these universities. Most of the self-assessment systems are Web-based static questionnaires. In this paper, a novel adaptive online self-assessment system AM I READY is introduced. The system is based on knowledge models, including static and dynamic user model, counseling model and self-assessment process model. It can dynamically filter questions to be asked to a specific user and adjust the contents of webpage dialog between the user and the system according to knowledge models and the user’s responses. The system is more effective and helpful than the usual ones

An Automatic Calibration Method for Near-infrared Camera in Optical Surgical Navigation

Optical surgical navigation system (SNS) with near-infrared tracking system is becoming extensively used in clinics, and the accuracy of SNS is influenced by the calibration of near-infrared cameras (NIRCs). We propose an automatic calibration method for NIRCs. The method is based on a designed calibration board. In our experiments, corners are automatically extracted to obtain the parameters of NIRCs. This method has the advantages of saving time, efficiency in computation, high accuracy, and reliability. In our experiments, an NIRC can be calibrated in only 5 s. Meanwhile, the average relative errors of the focal length and principal point are 0.87% and 1.39%, respectively

Two-Wave Mixing in Organic-Inorganic Hybrid Structures for Dynamic Holography

The chapter reviews recent progress of two-wave mixing in a novel organic-inorganic hybrid structures that combine essential properties as large anisotropy and strong birefringence, typical for organics with the excellent photosensitivity and photoconductivity of inorganics into single, compact devices. Depending on the designed assembly and operation principle, the proposed structures can record dynamic holographic gratings at Raman-Nath or Bragg regimes of diffraction, respectively. When the two beams interact in a structure based on a photoconductive material and birefringent layer (usually liquid crystal), the beam coupling with high amplification values occur in a liquid crystal layer, however, the fringe period of recorded holograms is limited to few μm scale. In contrast, when the two beams interact in a structure based on a photorefractive material and birefringent layer, the beam-coupling occurs in both composites, due to the surface activated photorefractive effect. The prime significance of the later structure is the ability to act as a holographic grating at Bragg regime allowing sub-micron spatial resolution. Moreover they are easy and simple to fabricate where the processes are all optically controlled. The above examples open scenarios to design new devices that meet the latest requirements of 3D display technologies and optical information processing

Pseudo-goldstino and electroweak gauginos at the LHC

The multi-sector SUSY breaking predicts the existence of pseudo-goldstino, which could couple more strongly to visible fields than ordinary gravitino. Then the lightest neutralino and chargino can decay into a pseudo-goldstino plus a Z-boson, Higgs boson or W-boson. In this note we perform a Monte Carlo simulation for the direct productions of the lightest neutralino and chargino followed by the decays to pseudo-goldstino. Considering scenarios with higgsino-like, bino-like or wino-like lightest neutralino, we find that the signal-to-background ratio at the high luminosity LHC is between 6% and 25% and the statistical significance can be above 5-sigma.Comment: Version in JHEP (LHC-8 results and discussions added