Oxygen isotope ratios in olivine from the Hawaii Scientific Drilling Project

Oxygen isotope ratios of olivine in 23 tholeiites from the Hawaii Scientific Drilling Project (HSDP) core (15 from Mauna Kea, 8 from Mauna Loa) and three samples of outcropping subaerial or dredged submarine Mauna Kea lavas have been measured by laser fluorination. The δ^(18)O values are 4.6–5.4 ‰, confirming previous observations that some Hawaiian lavas are derived from sources with δ^(18)O values lower than typical upper mantle (δ^(18)Oolivine ≈ 5.2±0.2 ‰). The Mauna Kea-Mauna Loa transition marks a shift from δ^(18)O values lower than the mantle average in Mauna Kea olivines (∼4.8) to more typical mantle values in Mauna Loa olivines. Lavas containing olivines with δ^(18)O values similar to the typical upper mantle are associated with more “primitive” or less depleted radiogenic isotope characteristics; i.e., with higher ^3He/^4He (>13 Ra), higher ^(87)Sr/^(86)Sr (>0.7036) and lower є_(Nd) (<6.5), and with ^(206)Pb/^(204)Pb ratios less than -18.3. These relationships indicate that the δ^(18)O values of the relatively enriched source components of the Hawaiian plume sampled by Mauna Loa lavas are comparable to (or greater than) the mantle average. This conclusion is supported by δ^(18)O values of olivine from other high ^3He/^4He islands, which are also comparable to the upper mantle average. The low δ^(18)O values in Hawaiian lavas are derived from a source having more MORB-like, or depleted, He, Nd, and Sr isotope ratios, but more radiogenic Pb than is seen in the Mauna Loa lavas Assimilation of ^(18)O-depleted lower oceanic crust from the underlying Pacific crust by hot, MgO-rich parental magmas or melting of older, recycled oceanic crust entrained in the Hawaiian plume are both possible sources of this ^(18)O-depleted, MORB-like component in Hawaiian magmas

The Effects of Human Resource Management Decisions on Shareholder Value

We examine the effects of selected human resource management decisions on the abnormal change in total shareholder return. Announcements of human resource decisions are classified into five types--general HR system announcements, compensation and benefits, staffing, shutdowns and relocations, and miscellaneous. Using an event study methodology we investigate whether any of these HR decisions had a discernible effect on either the level or variation of abnormal total shareholder return. We find no consistent pattern of increased or decreased valuation in response to the different types of HR announcements, even after controlling for the likely effect of such announcements on total compensation costs. We do find substantially increased variation in abnormal total shareholder return around the announcement date, which indicates that HR decisions do provide information to the stock market. The events associated with increased variation in total shareholder value are permanent staff reductions and shutdown/relocations. The absence of consistent valuation effects combined with the evidence of increased variation in shareholder value may be attributed to uncontrolled firm-specific factors, the categorization of the HR events or, simply, to the unique interpretations the market placed upon these events

The Boundaries of Partisan Gerrymandering

[Excerpt] “In my most recent column, I expressed concern about the effectiveness of the constitutional decision rules that currently govern gerrymandering – the redrawing of electoral districts in a manner that favors the incumbent majority at the expense of those out of power. Briefly, the Constitution has not been interpreted to prohibit redistricting with an eye toward advancing the interests of the political party in power. But it has been interpreted to bar legislators from redistricting on racial grounds – at least in most circumstances. The problem is that voters from certain racial groups tend to vote overwhelmingly for a single party. Thus, one way to gain partisan advantage in racially diverse states is to dilute the voting power of racial groups who tend to vote for the other party. This is accomplished by either “packing” voters from these groups into districts the other party is going to win anyway, or “cracking” them into a number of different legislative districts so that they fall somewhat short of a majority in each one. As matters now stand, redistricting that results in such packing and cracking is constitutional if a court finds that its “predominant purpose” was merely to secure partisan advantage. But it is unconstitutional if a court finds that racial motivations predominated.

Dark Town\u27s Wealth: A 150-Year-Old Rock-and-Roll Concert Review

I have a lot of odd things scattered around my house, weird ephemera and bric-a-brac that I\u27ve picked up here and there as I\u27ve studied history. Some of them are treasures, like CDVs of long-dead College professors and original pieces of decking from the USS North Carolina. Some are less treasures and more, well, junk. Most folks toss old newspapers within a few days of reading. In the Civil War Era, I\u27m sure many a page of newsprint went to start an honest mother\u27s hearth in the morning or a pile of moist kindling in some godforsaken camp. [excerpt

Gold coast slave ship bound for cotton fields... : Altamont and the American Civil War

A couple weeks ago, I put up a post about a flag flying at Manassas during the Sesquicentennial commemoration. It elicited a nice response from a friend of mine, Robby, who hails from the great state of North Carolina. Robby loves to play devil\u27s advocate, so I\u27m always happy to wade further into a friendly conversation: ...When a historian is unable to understand the southern affinity for the men who fought the war, almost to a person you see the slavery straw man emerge. This action is akin to politicians playing the race card, an easy way out of a confusing and hyper complex situation. In the end, most will not understand the paradoxical nature of southern feelings about the war and its outcome. They will denigrate flags, passion, and the oft-mentioned heritage as hallmarks of a society still stuck in the throes of antebellum histrionics. This is a gross simplification cast as philosophical enlightenment that is in reality a lack of such. Group think feeds group think in the end. [excerpt

Last Prisoners at Gettysburg: A Gift for Kind Hearts

I have been digging quite heavily into the history of Pennsylvania (Gettysburg) College and the American Civil War these past few months, trying to fill a gaping hole in the scholarship not only of the college but of the local civilian story in the war. This has meant long Thursday nights at Adams County Historical Society culling through every random mention of the college and the complex relationship which the students and faculty had with both the citizens of the borough and the armies which invaded it. It has also meant that I\u27ve had the opportunity to revisit Gettysburg College\u27s Special Collections in-depth for the first time since I began working with the college\u27s Civil War history in 2006. [excerpt

A New Theory for Battle Landscapes - Toward An Interpretive Future

There\u27s a misunderstanding. The misunderstanding has been long and deep. It goes something like this: Your crusade to destroy the current practice of military history on battlefields is a form of fundamentalism just like the supposed fundamentalism of military history you aim to change. [excerpt

Buckeye Blood Waters the Longleaf Pines

In the woods south of Wilmington, men in blue uniforms moved forward in a loose skirmish line. They were probing, trying to find General Hoke\u27s last line of defense. Brig. General Charles Paine sent the men forward to develop the enemy. But in the pine thicket ahead, in a thin, ragged line, the bedraggled rebel troops likely had more to fear than bullets as those skirmishers probed and prodded on a February day in 1865. [excerpt