Primary cerebellopontine angle melanocytoma: review.

Introduction Primary cerebellopontine angle melanocytomas (PCPAMs) are very rare. Their natural history and prognosis are not fully understood. We reviewed the literature and add a new case to analyze PCPAM's presentation, radiological features, and outcome of treatment. Methods We performed a literature review using Medline, Embase, PubMed, and Cochrane databases. We searched for melanocytoma, melanoma, and pigmented tumors in the posterior cranial fossa and CPA to identify PCPAM. We have also searched our institution's neuro-oncology database. Results We identified 23 PCPAM from the literature and one case of our own. The mean age at presentation was 44.4 years with slight male preponderance. PCPAM presented with cerebellopontine angle (CPA) syndrome with or without hydrocephalus. Preoperative diagnosis was difficult; they appeared hyperintense on T1 and isointense on T2 magnetic resonance imaging (MRI) and enhanced with gadolinium. However, the final diagnosis was only made by immunohistochemical examination. Total surgical resection of PCPAM was associated with prolonged survival while subtotal excision was associated with frequent recurrence. Conclusion PCPAM are very rare and should be considered in the differential diagnosis of all CPA lesions that appear hyperintense on T1 and isointense on T2 MRI images. Patients with PCPAM should undergo total surgical resection to avoid fatal recurrences

Molecular Dynamics simulations of concentrated aqueous electrolyte solutions

Transport properties of concentrated electrolytes have been analyzed using classical molecular dynamics simulations with the algorithms and parameters typical of simulations describing complex electrokinetic phenomena. The electrical conductivity and transport numbers of electrolytes containing monovalent (KCl), divalent (MgCl$_2$), a mixture of both (KCl + MgCl$_2$), and trivalent (LaCl$_3$) cations have been obtained from simulations of the electrolytes in electric fields of different magnitude. The results obtained for different simulation parameters have been discussed and compared with experimental measurements of our own and from the literature. The electroosmotic flow of water molecules induced by the ionic current in the different cases has been calculated and interpreted with the help of the hydration properties extracted from the simulations

Labor market transitions of young women over the early life course: A multistate life table analysis

Using detailed panel data on school, work, and family formation history of youth (i.e., NLSY 1979-1991), we examine the dynamic process of labor market transitions women make during young adulthood. Transitions between the states of the labor force (i.e., employment, unemployment, and out of the labor force) are analyzed using multistate life tables, in which labor market and family transitions are estimated simultaneously. The age-pattern, life-cycle variation, and racial differences in employment and nonemployment transitions are the main interests of this study. We find that black women in the aggregate are less likely to be employed (or in the labor force) and more likely to be nonemployed than white women during early adulthood (i.e., at ages 16-34). With first childbirth controlled, a higher proportion of black women than white women are in the labor force during the same period, as past studies have shown. But, we find that the proportion employed is actually lower among blacks than among whites because a higher proportion of blacks are unemployed. Even though the racial differential in employment decreases with age among women with more than a high school education, it persists among women with a high school education or less. By estimating the conditional probabilities of transitions between states of the labor force, this study shows that the major component of the racial differential in employment (or in nonemployment) is in the process of entering employment either from the unemployment or the out-of-the-labor-force state: black women, if in the labor force, are less likely to be employed and more likely to withdraw from the labor force, if unemployed, than their white counterparts. As a summary measure, our life table analysis shows that black women spend considerably more time nonemployed and less time employed than white women over the early life course.

The effect of desiccation on the emission of volatile bromocarbons from two common temperate macroalgae

Exposure of intertidal macroalgae during low tide has been linked to the emission of a variety of atmospherically-important trace gases into the coastal atmosphere. In recent years, several studies have investigated the role of inorganic iodine and organoiodides as antioxidants and their emission during exposure to combat oxidative stress, yet the role of organic bromine species during desiccation is less well understood. In this study the emission of dibromomethane (CH2Br2) and bromoform (CHBr3) during exposure and desiccation of two common temperate macroalgae, Fucus vesiculosus and Ulva intestinalis, is reported. Determination of the impact exposure may have on algal physiological processes is difficult as intertidal species are adapted to desiccation and may undergo varying degrees of desiccation before their physiology is affected. For this reason we include comparisons between photosynthetic capacity (Fv/Fm) and halocarbon emissions during a desiccation time series. In addition, the role of rewetting with freshwater to simulate exposure to rain was also investigated. Our results show that an immediate flux of bromocarbons occurs upon exposure, followed by a decline in bromocarbon emissions. We suggest that this immediate bromocarbon pulse may be linked to volatilisation or emissions of existing bromocarbon stores from the algal surface rather than the production of bromocarbons as an antioxidant response

The Past and Future of Korean Pension System: A Proposal for a Coordinated Development of the Public-Private Pensions

Korean pension system is at a crossroads. National pension - introduced in 1988 and still young - is facing a question of long-term financial sustainability. It is projected to be depleted by around 2040 even with its recent parametric reform. On the other hand, special occupational pension schemes for civil servants, military personnel and private school teachers have long been in financially weak status. Korean public pension system carries a problem of unviable contribution-benefit imbalance built in its design giving too generous benefit to its first generation participants and leaving too much burden to its next generation. In this paper, a reform proposal is suggested and detailed for a coordinated integration of public-private pension schemes into a viable and modernized multi-pillar system, in which is included a programmed conversion of the current mandatory retirement allowance scheme into a corporate pension system.

Direct comparison of boron, phosphorus, and aluminum gettering of iron in crystalline silicon

This paper presents a direct quantitative comparison of the effectiveness of borondiffusion, phosphorus diffusion, and aluminumalloying in removing interstitial iron in crystalline silicon in the context of silicon solar cells. Phosphorus diffusion gettering was effective in removing more than 90% of the interstitial iron across a range of diffusion temperatures, sheet resistances, and iron doses. Even relatively light phosphorus diffusions (145 Ω/□) were found to give very effective gettering, especially when combined with extended low temperature annealing.Aluminumalloying was extremely effective and removed more than 99% of the implanted iron for a range of alloying temperatures and aluminum film thicknesses. In contrast, our experimental results showed that borondiffusion gettering is very sensitive to the deposition conditions and can change from less than 5% of the Fe being gettered to more than 99.9% gettered by changing only the gas flow ratios and the post-oxidation step

A reform proposal for Korean pension system

노트 : OECD/INPRS/KOREA Conference on Private Pensions in Asia October 24-25, Seoul, Kore

From manual to electronic road congestion pricing: The Singapore experience and experiment

Transportation Research Part E: Logistics and Transportation Review33297-10

Dark Matter in Gauge Mediation from Emergent Supersymmetry

We investigated the viability of neutralino dark matter in the gauge mediation from emergent supersymmetry proposal. In this proposal, supersymmetry is broken at Planck scale and consequently, the gravitino is superheavy and completely decouples from the low energy theory. Squarks and sleptons obtain their soft masses dominantly through gauge mediation with other mechanisms highly suppressed. The lightest supersymmetric partner, in contrast to traditional gauge mediation, is a neutralino which is also a dark matter candidate. By explicit calculation of the low energy spectra, the parameter space was constrained using the WMAP observed relic density of dark matter, LEP2 Higgs mass bounds, collider bounds on supersymmetric partners and exotic B-meson decays. We found that the model has intriguing hybrid features such as a nearly gauge-mediated spectrum (the exception being the superheavy gravitino) but with a dominant mSUGRA-like bino-stau coannihilation channel and at large $\tan \beta$, A-resonance-like annihilation.Comment: 14 pages, 4 figure