Galactic Center Shells and a Recurrent Starburst Model

By applying filtering techniques to remove straight filaments in the 20-cm VLA radio image of the Galactic Center Arc region, we have shown that numerous concentric radio shells of radii 5 to 20 pc are surrounding the Pistol and Sickle region, which we call Galactic Center Shells (GCS). Each shell has thermal energy of the order of $10^{49-50}$ erg. Several CO-line shells are associated, whose kinetic energies are of the order of $10^{49-50}$ erg. Summing up the energies of recognized GCSs, the total energy amounts to $\sim 10^{51}$ erg. The GCSs show an excellent correlation with the FIR shells observed at 16--26 microns with the MSX. We propose a model in which GCSs were produced by recurrent and/or intermittent starbursts in the Pistol area during the last million yr. The most recent burst occurred some $10^5$ years ago, producing an inner round-shaped shell (GCS I); earlier ones a million years ago produced outer shells (GCS II and III), which are more deformed by interactions with the surrounding ISM and Sgr A halo. We argue that recurrent starbursts had also occurred in the past, which produced larger scale hyper shell structures as well. A burst some million years ago produced the Galactic Center Lobe, and a much stronger one 15 million years ago produced the North Polar Spur.Comment: To appear in PASJ, Latex 8 pages, 5 figures, See http://www.ioa.s.u-tokyo.ac.jp/~sofue/htdocs/2003gcs/ for original figure

Early impact basins and the onset of plate tectonics

The fundamental crustal dichotomy of the Earth (high and low density crust) was established nearly 4 billion years ago. Therefore, subductable crust was concentrated at the surface of the Earth very early in its history, making possible an early onset for plate tectonics. Simple thermal history calculations spanning 1 billion years show that the basin forming impact thins the lithosphere by at least 25%, and increases the sublithosphere thermal gradients by roughly 20%. The corresponding increase in convective heat transport, combined with the highly fractured nature of the thinned basin lithosphere, suggest that lithospheric breakup or rifting occurred shortly after the formation of the basins. Conditions appropriate for early rifting persisted from some 100,000,000 years following impact. We suggest a very early stage of high temperature, fast spreading "microplate" tectonics, originating before 3.5 billion years ago, and gradually stabilizing over the Archaean into more modern large plate or Wilson Cycle tectonics

Social Security and the Age of Retirement

Unlike a century ago, people expect their children to live past the age of retirement. This fact has important implications for how workers save for retirement, but has no specific implications for the retirement portion of Social Security. In addition, the increase in life expectancy is not nearly as important as it might first appear. A significant part of the increase in life is between birth and age 20. Including declines in child and teen mortality exaggerate the increase in retirement length. Furthermore, much of the gains in life expectancy come during working years -- between age 20 and retirement. This means that workers are not only experiencing longer retirements, but longer working lives as well. Finally, each succeeding generation has been vastly more productive than prior generations -- a trend that will continue. Thus, not only have workers on average more years of work over their lifetime, they are better able to save for their retirements

Top quark properties

The top quark physics has entered the precision era. The CDF and D0 collaborations are finalizing their legacy results of the properties of the top quark after the shutdown of the Fermilab Tevatron three years ago. The ATLAS and CMS collaborations have been publishing results from the LHC Run I with 7 TeV and 8 TeV proton-proton collisions, with many more forthcoming. We present a selection of recent results produced by the Tevatron and LHC experiments.Comment: Presented at XXXIV Physics in Collision Symposium, Bloomington, Indiana, September 16-20, 2014, 10 pages, 5 figure

If We Don\u27t Take Care of Young Lawyers, Who Will?

There are now more than 450,000 lawyers in this country, almost double the number of 20 years ago. The American Association of Law Schools estimates that the number of law student graduates averages about 34,000 a year. And the Bureau of Labor Statistics of the Department of Labor projects that there will be 26,400 new legal jobs each year until 1985. If law school enrollments stay at their current level, that would mean about 8,000 graduates each year would not be able to find a law-related job

Support for Same-Sex Marriage at Record High, but Key Segments Remain Opposed

As the Supreme Court prepares to decide a key case involving states' requirements to recognize same-sex marriage, public support for allowing gays and lesbians to marry legally continues its rapid rise: A 57%-majority of Americans now favor allowing same-sex marriage and 39% oppose. As recently as five years ago, more opposed (48%) same-sex marriage than supported it (42%).This is the highest level of support measured for same-sex marriage in nearly 20 years of Pew Research Center polling of the issue. Yet even as support for same-sex marriage has increased among nearly all segments in the public, some groups remain broadly opposed to gay marriage.The Pew Research Center survey, conducted May 12-18 among 2,002 adults, finds that partisans are as divided on this issue as ever: Today, 65% of Democrats and an identical percentage of independents favor gay marriage; only about one third (34%) of Republicans do so. Growing shares of all three groups support same-sex-marriage, yet the differences between Democrats and Republicans are as wide today as they were a decade ago