Motor Bus Deregulation and the Gender Wage Gap: A Test of the Becker Hypothesis

This study provides a test of Becker's hypothesis that wage discrimination within an industry depends on the degree of market competition by analyzing earnings in a deregulated transportation sector--the motor bus industry. The empirical findings provide strong support for the hypothesis that motor bus deregulation, by creating an increasingly competitive environment, makes discrimination more costly and provides greater incentives for firms to employ female drivers. The earnings status of unionized white female drivers relative to white males improved significantly subsequent to deregulation, with female wages increasing even as the real wage level for male drivers declined.Bus; Deregulation; Discrimination; Female; Gender; Transportation

Getting a kick out of numerical relativity

Recent developments in numerical relativity have made it possible to follow reliably the coalescence of two black holes from near the innermost stable circular orbit to final ringdown. This opens up a wide variety of exciting astrophysical applications of these simulations. Chief among these is the net kick received when two unequal mass or spinning black holes merge. The magnitude of this kick has bearing on the production and growth of supermassive black holes during the epoch of structure formation, and on the retention of black holes in stellar clusters. Here we report the first accurate numerical calculation of this kick, for two nonspinning black holes in a 1.5:1 mass ratio, which is expected based on analytic considerations to give a significant fraction of the maximum possible recoil. We have performed multiple runs with different initial separations, orbital angular momenta, resolutions, extraction radii, and gauges. The full range of our kick speeds is 86--116 km s$^{-1}$, and the most reliable runs give kicks between 86 and 97 km s$^{-1}$. This is intermediate between the estimates from two recent post-Newtonian analyses and suggests that at redshifts $z\gtrsim 10$, halos with masses $\lesssim 10^9 M_\odot$ will have difficulty retaining coalesced black holes after major mergers.Comment: Updated. Accepted by ApJ Letter

Spontaneous Uterine Rupture in the First Trimester: A Case Report

Uterine rupture is one of the most feared obstetric complications affecting the pregnant woman and fetus. Most of the cases have various risk factors and mainly occur during the second or third trimester. However, spontaneous uterine rupture during the first trimester is extremely rare. We experienced a case of spontaneous uterine rupture in a 36-yr-old multiparous woman without definite risk factors. The initial impression was a hemoperitoneum of an unknown origin with normal early pregnancy. Intensive surgical method would be needed for accurate diagnosis and immediate management in bad situation by hemoperitoneum even though a patient was early pregnancy

Relics of cosmological quark-hadron phase transition

We propose that the amplified density fluctuations by the vanishing sound velocity effect during the cosmological quark-hadron phase transition lead to quark-gluon plasma lumps decoupled from the expansion of the universe, which may evolve to quark nuggets (QNs). Assuming power-law spectrum of density fluctuations, we investigate the parameter ranges for the QNs to play the role of baryonic dark matter and give inhomogeneities which could affect big-bang nucleosynthesis within the observational bounds of CMBR anisotropy. The QNs can give the strongest constraint ever found on the spectral index.Comment: REVTEX, 4 pages, 2 eps figure

Hypokalemic periodic paralysis; two different genes responsible for similar clinical manifestations

Primary hypokalemic periodic paralysis (HOKPP) is an autosomal dominant disorder manifesting as recurrent periodic flaccid paralysis and concomitant hypokalemia. HOKPP is divided into type 1 and type 2 based on the causative gene. Although 2 different ion channels have been identified as the molecular genetic cause of HOKPP, the clinical manifestations between the 2 groups are similar. We report the cases of 2 patients with HOKPP who both presented with typical clinical manifestations, but with mutations in 2 different genes (CACNA1Sp.Arg528His and SCN4A p.Arg672His). Despite the similar clinical manifestations, there were differences in the response to acetazolamide treatment between certain genotypes of SCN4A mutations and CACNA1S mutations. We identified p.Arg672His in the SCN4A gene of patient 2 immediately after the first attack through a molecular genetic testing strategy. Molecular genetic diagnosis is important for genetic counseling and selecting preventive treatment

Renal Artery Embolization Using a New Liquid Embolic Material Obtained by Partial Hydrolysis of Polyvinyl Acetate (Embol): Initial Experience in Six Patients

Objective To evaluate the therapeutic efficacy of a new liquid embolic material, Embol, in embolization of the renal artery. Materials and Methods Embol is a new embolic material obtained by partial hydrolysis of polyvinyl acetate mixed in absolute ethanol and Iopromide 370 and manufactured by Schering Korea, Kyonggido, Korea. Six patients who underwent embolization of the renal artery using Embol were evaluated. Four were male and two were female and their ages ranged from 11 to 70 (mean, 53) years. Clinical and radiologic diagnoses referred for renal artery embolization were renal cell carcinoma (n = 3), renal angiomyolipoma (n = 2) and pseudoaneurysm of the renal artery (n = 1). After selective renal angiography, Embol was injected through various catheters, either with or without a balloon occlusion catheter. Changes in symptoms and blood chemistry which may have been related to renal artery embolization with Embol were analyzed. Results The six patients showed immediate total occlusion of their renal vascular lesions. One of the three in whom renal cell carcinoma was embolized with Embol underwent radical nephrectomy, and the specimen thus obtained revealed 40% tumor necrosis. In the two patients with angiomyolipomas, the tumors decreased in size and abdominal pain subsided. Bleeding from pseudoaneurysm of the renal artery was successfully controlled. Four patients showed symptoms of post-embolization syndrome, and one of these also showed increased levels of blood urea nitrogen and creatinine. One patient experienced transient hypertension. Conclusion Embol is easy to use, its radiopacity is adequate and it is a safe and effective embolic material which provides immediate and total occlusion of renal vascular lesions.ope

Modeling bursts and heavy tails in human dynamics

Current models of human dynamics, used from risk assessment to communications, assume that human actions are randomly distributed in time and thus well approximated by Poisson processes. We provide direct evidence that for five human activity patterns the timing of individual human actions follow non-Poisson statistics, characterized by bursts of rapidly occurring events separated by long periods of inactivity. We show that the bursty nature of human behavior is a consequence of a decision based queuing process: when individuals execute tasks based on some perceived priority, the timing of the tasks will be heavy tailed, most tasks being rapidly executed, while a few experiencing very long waiting times. We discuss two queueing models that capture human activity. The first model assumes that there are no limitations on the number of tasks an individual can hadle at any time, predicting that the waiting time of the individual tasks follow a heavy tailed distribution with exponent alpha=3/2. The second model imposes limitations on the queue length, resulting in alpha=1. We provide empirical evidence supporting the relevance of these two models to human activity patterns. Finally, we discuss possible extension of the proposed queueing models and outline some future challenges in exploring the statistical mechanisms of human dynamics.Comment: RevTex, 19 pages, 8 figure

Manifestation of the Pacific Decadal Oscillation in the Kuroshio

Author Posting. © American Geophysical Union, 2009. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 36 (2009): L16602, doi:10.1029/2009GL039216.Pacific Decadal Oscillation (PDO) index is strongly correlated with vertically integrated transport carried by the Kuroshio through the East China Sea (ECS). Transport was determined from satellite altimetry calibrated with in situ data and its correlation with PDO index (0.76) is highest at zero lag. Total PDO-correlated transport variation carried by the ECS-Kuroshio and Ryukyu Current is about 4 Sv. In addition, PDO index is strongly negatively correlated, at zero lag, with NCEP wind-stress-curl over the central North Pacific at ECS latitudes. Sverdrup transport, calculated from wind-stress-curl anomalies, is consistent with the observed transport variations. Finally, PDO index and ECS-Kuroshio transport are each negatively correlated with Kuroshio Position Index in the Tokara Strait; this can be explained by a model in which Kuroshio path is steered by topography when transport is low and is inertially controlled when transport is high.MA, MW and JP were supported by ONR grant N000140210271. XZ was supported by the National Natural Science Foundation of China under grant 40776021 and the National Basic Research Programs of China under grant 2006CB400603. KK and KC were supported by the Korea EAST-I Program