Hope vs. Fear: The Debate Over a State Constitutional Convention

On November 7, 2017, New Yorkers will go to their polling places and receive ballots containing a thirteen-word referendum question: “Shall there be a convention to revise the constitution and amend the same?” That question appears on the ballot because the New York State Constitution commands that at least once every twenty years voters are asked whether or not to call a constitutional convention. The mandatory referendum reflects Thomas Jefferson’s belief that every generation the people should be given a chance to revise their basic law

Critique of Architectures for Long-Term Digital Preservation

Evolving technology and fading human memory threaten the long-term intelligibility of many kinds of documents. Furthermore, some records are susceptible to improper alterations that make them untrustworthy. Trusted Digital Repositories (TDRs) and Trustworthy Digital Objects (TDOs) seem to be the only broadly applicable digital preservation methodologies proposed. We argue that the TDR approach has shortfalls as a method for long-term digital preservation of sensitive information. Comparison of TDR and TDO methodologies suggests differentiating near-term preservation measures from what is needed for the long term. TDO methodology addresses these needs, providing for making digital documents durably intelligible. It uses EDP standards for a few file formats and XML structures for text documents. For other information formats, intelligibility is assured by using a virtual computer. To protect sensitive information—content whose inappropriate alteration might mislead its readers, the integrity and authenticity of each TDO is made testable by embedded public-key cryptographic message digests and signatures. Key authenticity is protected recursively in a social hierarchy. The proper focus for long-term preservation technology is signed packages that each combine a record collection with its metadata and that also bind context—Trustworthy Digital Objects.

Homelessness Counts: Changes in Homelessness from 2005 to 2007

In 2007, the National Alliance to End Homelessness released Homelessness Counts, establishing a 2005 baseline for measuring progress in the fight to end homelessness. This report is a follow up to that report. Here, we analyze the changes from 2005 to 2007, looking more closely at changes at the state level and among subpopulations

The free energies of formation of aqueous d-alanine, l-aspartic acid, and d-glutamic acid

The employment of thermodynamics in biochemistry has been restricted, until recently, to the use of first law data. In the last few years a beginning has been made in the application of the second law; i.e., of free energy data (1, 2). The development of this field is limited by the paucity of available free energy data. We have therefore undertaken the systematic determination of the free energies of formation of compounds which may be interesting in biochemistry or physiology

Saltation on Mars and expected lifetime of Viking 75 wind sensors

With the use of the wind-tunnel measurements of Bagnold and Zingg, a model is developed for estimating the parameters that describe the flux of sand on Mars. Application of this model to the sensor-breakage problem indicates that the expected lifetime on Mars of the wind sensors of the Viking 75 Meteorology Instrument System is about 40 earth years. This expected lifetime is adequate for both the primary Viking 75 mission and for a proposed extended mission

Commodity Prices Rock World Markets: Structural Shift or Short Term Adjustments?

International Relations/Trade,

Entrainment and scattering in microswimmer--colloid interactions

We use boundary element simulations to study the interaction of model microswimmers with a neutrally buoyant spherical particle. The ratio of the size of the particle to that of the swimmer is varied from $R^\mathrm{P} / R^\mathrm{S} \ll 1$, corresponding to swimmer--tracer scattering, to $R^\mathrm{P} / R^\mathrm{S} \gg 1$, approximately equivalent to the swimmer interacting with a fixed, flat surface. We find that details of the swimmer and particle trajectories vary for different swimmers. However, the overall characteristics of the scattering event fall into two regimes, depending on the relative magnitudes of the impact parameter, $\rho$, and the collision radius, $R^\mathrm{coll}=R^\mathrm{P} + R^\mathrm{S}$. The range of particle motion, defined as the maximum distance between two points on the trajectory, has only a weak dependence on the impact parameter when $\rho < R^\mathrm{coll}$ and decreases with the radius of the particle. In contrast, when $\rho>R^\mathrm{coll}$ the range decreases as a power law in $\rho$ and is insensitive to the size of the particle. We also demonstrate that large particles can cause swimmers to be deflected through large angles. In some instances, this swimmer deflection can lead to larger net displacements of the particle. Based on these results, we estimate the effective diffusivity of a particle in a dilute bath of swimmers and show that there is a non-monotonic dependence on particle radius. Similarly, we show that the effective diffusivity of a swimmer scattering in a suspension of particles varies non-monotonically with particle radius.Comment: 19 pages, 11 figures. Accepted in Physical Review Fluid