DOES UNDOCUMENTED IMMIGRATION INCREASE VIOLENT CRIME?

Despite substantial public, political, and scholarly attention to the issue of immigration and crime, we know little about the criminological consequences of undocumented immigration. As a result, fundamental questions about whether undocumented immigration increases violent crime remain unanswered. In an attempt to address this gap, we combine newly developed estimates of the unauthorized population with multiple data sources to capture the criminal, socioeconomic, and demographic context of all 50 states and Washington, DC, from 1990 to 2014 to provide the first longitudinal analysis of the macro-level relationship between undocumented immigration and violence. The results from fixed-effects regression models reveal that undocumented immigration does not increase violence. Rather, the relationship between undocumented immigration and violent crime is generally negative, although not significant in all specifications. Using supplemental models of victimization data and instrumental variable methods, we find little evidence that these results are due to decreased reporting or selective migration to avoid crime. We consider the theoretical and policy implications of these findings against the backdrop of the dramatic increase in immigration enforcement in recent decades.

Three-dimensional structure of human serum albumin

The three-dimensional structure of human serum albumin has been solved at 6.0 angstrom (A) resolution by the method of multiple isomorphous replacement. Crystals were grown from solutions of polyethylene glycol in the infrequently observed space group P42(1)2 (unit cell constants a = b = 186.5 +/- 0.5 A and c = 81.0 +/- 0.5 A) and diffracted x-rays to lattice d-spacings of less than 2.9 A. The electron density maps are of high quality and revealed the structure as a predominantly alpha-helical globin protein in which the course of the polypeptide can be traced. The binding loci of several organic compounds have been determined.

New experimental approaches to the isoelectric fractionation of cells

Several parameters that could affect the survival rate and the resolution of cells in continuous-flow isoelectric focusing have been investigated. Cell survival at progressively lower pHs was found to be a function of the osmolarity of the medium: at pH 4 there was an absolute requirement for a 300 mOsm environment. A pH-dependent interaction of the carrier ampholytes with the cell surface has been demonstrated. The binding was very strong at pH 4, weak at pH 5 and totally abolished above pH 5. The same interaction was obtained with pentaethylenehexamine, the polyamino backbone of carrier ampholytes, stripped of carboxyl groups. A model was derived showing how at pH 4 the oligocationic carrier ampholytes, via their nitrogen groups, would bind to the polyanionic cell surface. The Hannig apparatus was adapted for cell separation in a continuously flowing curtain of isoelectric ampholytes. The medium osmolarity was maintained with glycine (delta pK 7.2), taurine (delta pK 8.5) and trimethylaminopropionyl sulphonate (TMAPS, delta pK 11). With increasing delta pK, the pH range that can be created in the presence of these compounds progressively widens, from a pH 4.3-7.5 range with glycine, to pH 3.5-7.5 with taurine up to pH 3.5-9.5 with TMAPS. The 48 fractions collected were routinely assayed for conductivity, osmolarity and pH.