DNA sequencing by delayed extraction-matrix-assisted laser desorption/ionization time of flight mass spectrometry.

Matrix-assisted laser desorption/ionization (MALDI) time of flight mass spectrometry was used to detect and order DNA fragments generated by Sanger dideoxy cycle sequencing. This was accomplished by improving the sensitivity and resolution of the MALDI method using a delayed ion extraction technique (DE-MALDI). The cycle sequencing chemistry was optimized to produce as much as 100 fmol of each specific dideoxy terminated fragment, generated from extension of a 13-base primer annealed on 40- and 50-base templates. Analysis of the resultant sequencing mixture by DE-MALDI identified the appropriate termination products. The technique provides a new non-gel-based method to sequence DNA which may ultimately have considerable speed advantages over traditional methodologies.

Hα emission fluxes and lithium abundances of low-mass stars in the young open cluster IC 4665

As part of a long term effort to understand pre-main sequence Li burning, we have obtained high resolution spectroscopic observations of 14 late type stars (G0-M1) in the young open cluster IC 4665. Most of the stars have Hα filled-in and Li I absorption, as expected for their young age. From the equivalent widths of Hα emission excess (obtained using the spectral subtraction technique) and the the Li i λ6708 feature, we have derived Hα emission fluxes and photospheric Li abundances. The mean Li abundance of IC 4665 solar-type stars is log N(Li) = 3.1; the same as in other young clusters (α Per, Pleiades) and T Tauri stars. Our results support the conclusions from previous works that PMS Li depletion is very small for masses ∼ 1 M_⨀ . Among the IC 4665 late-G and early K-type stars, there is a spread in Li abundances of about one order of magnitude. The Li-poor IC 4665 members have low Hα excess and vsini≤10. Hence, the Li-activity-rotation connection which has been clearly established in the Pleiades also seems to hold in IC 4665. One M-type IC 4665 star that we have observed does not show Li, implying a very efficient Li depletion as observed in α Per stars of the same spectral type. The level of chromospheric activity and Li depletion among the low-mass stars of IC 4665 is similar to that in the Pleiades. In fact, we note that the Li abundance distributions in several young clusters (α Per, Pleiades, IC 2391, IC 4665) and in post T Tauri stars are strikingly similar. This result suggests that Hα emission and Li abundance not well correlated with age for low-mass stars between 20 and 100 Myr old. We argue that a finer age indicator, the ''LL-clock'', would be the luminosity at which the transition between efficient Li depletion and preservation takes place for fully convective objects. The LL-clock could allow in the near future to derive the relative ages of young open clusters, and clarify the study of PMS evolution of cool stars.

The Battle of the Bulge: The Surprising Last Stand Against State Marijuana Legalization

Although marijuana possession remains a federal crime, twenty-three states now allow use of marijuana for medical purposes and four states have adopted tax-and-regulate policies permitting use and possession by those twenty-one and over. In this article, I examine recent developments regarding marijuana regulation. I show that the Obama administration, after initially sending mixed signals, has taken several steps indicating an increasingly accepting position toward marijuana law reform in states; however the current situation regarding the dual legal status of marijuana is at best an unstable equilibrium. I also focus on what might be deemed the last stand of marijuana-legalization opponents, in the form of lawsuits filed by several states, sheriffs, and private plaintiffs challenging marijuana reform in Colorado (and by extension elsewhere). This analysis offers insights for federalism scholars regarding the speed with which marijuana law reform has occurred, the positions taken by various state and federal actors, and possible collaborative federalism solutions to the current state-federal standoff.

Accreting magnetars: a new type of high-mass X-ray binaries?

The discovery of very slow pulsations (Pspin =5560 s) has solved the long-standing question of the nature of the compact object in the high-mass X-ray binary 4U 2206+54 but has posed new ones. According to spin evolutionary models in close binary systems, such slow pulsations require a neutron star magnetic field strength larger than the quantum critical value of 4.4 × 1013 G, suggesting the presence of a magnetar. We present the first XMM–Newton observations of 4U 2206+54 and investigate its spin evolution. We find that the observed spin-down rate agrees with the magnetar scenario. We analyse Integral Spacecraft Gamma-Ray Imager (ISGRI)/INTErnational Gamma-RAy Laboratory (INTEGRAL) observations of 4U 2206+54 to search for the previously suggested cyclotron resonance scattering feature at ∼30 keV. We do not find a clear indication of the presence of the line, although certain spectra display shallow dips, not always at 30 keV. The association of these dips with a cyclotron line is very dubious because of its apparent transient nature. We also investigate the energy spectrum of 4U 2206+54 in the energy range 0.3–10 keV with unprecedented detail and report for the first time the detection of very weak 6.5 keV fluorescence iron lines. The photoelectric absorption is consistent with the interstellar value, indicating very small amount of local matter, which would explain the weakness of the florescence lines. The lack of matter locally to the source may be the consequence of the relatively large orbital separation of the two components of the binary. The wind would be too tenuous in the vicinity of the neutron star.

Vote of the Selectmen of Boston respecting Clarke's children, 1780 August 30

One-page handwritten copy of the vote of the Boston Selectmen responding to Croswell's complaint, as usher of the South Grammar School of Boston, against a parent.

Certificate of the Selectmen of Boston, 1787 August 22

Two handwritten copies of a document certifying Croswell's employment as an usher in the Boston South Public Grammar School.

Note from William Croswell to the Selectmen of Boston, 1782 June 5

A brief one-page note from Croswell resigning from the South Grammar School.

Memorial to the City of Boston, 1826 May

One draft of a letter.

Memorial to the Overseers of the Poor of Boston, 1826 June 21

Two drafts of a letter.

Memorial to the Overseers of the Poor of Boston, 1826 August 21

One draft of a letter.

Petition to the City of Boston, 1827 June 18

Two drafts of a letter.

Letter from William Croswell to the City Council of Boston, 1827 September 4

Drafts of a letter concerning Croswell's June 1827 petition to the City Council.