The Carboxyl-Terminal Segment of Apolipoprotein A-V Undergoes a Lipid-Induced Conformational Change

Apolipoprotein (apo) A-V is a 343-residue, multidomain protein that plays an important role in regulation of plasma triglyceride homeostasis. Primary sequence analysis revealed a unique tetraproline sequence (Pro293-Pro296) near the carboxyl terminus of the protein. A peptide corresponding to the 48-residue segment beyond the tetraproline motif was generated from a recombinant apoA-V precursor wherein Pro295 was replaced by Met. Cyanogen bromide cleavage of the precursor protein, followed by negative affinity chromatography, yielded a purified peptide. Nondenaturing polyacrylamide gel electrophoresis verified that apoA-V(296-343) solubilizes phospholipid vesicles, forming a relatively heterogeneous population of reconstituted high-density lipoprotein with Stokes’ diameters\u3e17 nm. At the same time, apoA-V(296-343) failed to bind a spherical lipoprotein substrate in vitro. Far-UV circular dichroism spectroscopy revealed the peptide is unstructured in buffer yet adopts significant R-helical secondary structure in the presence of the lipid mimetic solvent trifluoroethanol (TFE; 50% v/v). Heteronuclear multidemensional NMR spectroscopy experiments were conducted with uniformly 15N- and 15N/13C-labeled peptide in 50% TFE. Peptide backbone assignment and secondary structure prediction using TALOSþ reveal the peptide adopts R-helix secondary structure from residues 309 to 334. In TFE, apoA-V(296-343) adopts an extended amphipathic R-helix, consistent with a role in lipoprotein binding as a component of full-length apoA-V

Site percolation and random walks on d-dimensional Kagome lattices

The site percolation problem is studied on d-dimensional generalisations of the Kagome' lattice. These lattices are isotropic and have the same coordination number q as the hyper-cubic lattices in d dimensions, namely q=2d. The site percolation thresholds are calculated numerically for d= 3, 4, 5, and 6. The scaling of these thresholds as a function of dimension d, or alternatively q, is different than for hypercubic lattices: p_c ~ 2/q instead of p_c ~ 1/(q-1). The latter is the Bethe approximation, which is usually assumed to hold for all lattices in high dimensions. A series expansion is calculated, in order to understand the different behaviour of the Kagome' lattice. The return probability of a random walker on these lattices is also shown to scale as 2/q. For bond percolation on d-dimensional diamond lattices these results imply p_c ~ 1/(q-1).Comment: 11 pages, LaTeX, 8 figures (EPS format), submitted to J. Phys.

Evolution of surname distribution under gender-equality measurements

We consider a model for the evolution of the surnames distribution under a gender-equality measurement presently discussed in the Spanish parliament (the children take the surname of the father or the mother according to alphabetical order). We quantify how this would bias the alphabetical distribution of surnames, and analyze its effect on the present distribution of the surnames in Spain

“Contagious Accountability”: A Global Multisite Randomized Controlled Trial on the Effect of Police Body-Worn Cameras on Citizens’ Complaints Against the Police

The use of body-worn cameras (BWCs) by the police is rising. One proposed effect of BWCs is reducing complaints against police, which assumes that BWCs reduce officer noncompliance with procedures, improve suspects’ demeanor, or both, leading to fewer complaints. We report results from a global, multisite randomized controlled trial on whether BWC use reduces citizens’ complaints. Seven discrete tests ( N = 1,847 officers), with police shifts as the unit of analysis ( N = 4,264), were randomly assigned into treatment and control conditions. Using a prospective meta-analytic approach, we found a 93% before–after reduction in complaint incidence ( Z = −3.234; p < .001), but no significant differences between trial arms in the studies ( d = .053, SE = .11; 95% confidence interval [CI] = [−.163, .269]), and little between-site variation ( Q = 4.905; p = .428). We discuss these results in terms of an “observer effect” that influences both officers’ and citizens’ behavior and assess what we interpret as treatment diffusion between experimental and control conditions within the framework of “contagious accountability.” This is the author accepted manuscript. The final version is available from SAGE Publications via http://dx.doi.org/10.1177/009385481666821

Pregnancy and childbirth in English prisons : institutional ignominy and the pains of imprisonment

© 2020 The Authors. Sociology of Health & Illness published by John Wiley & Sons Ltd on behalf of Foundation for SHIL.With a prison population of approximately 9000 women in England, it is estimated that approximately 600 pregnancies and 100 births occur annually. Despite an extensive literature on the sociology of reproduction, pregnancy and childbirth among women prisoners is under‐researched. This article reports an ethnographic study in three English prisons undertaken in 2015‐2016, including interviews with 22 prisoners, six women released from prison and 10 staff members. Pregnant prisoners experience numerous additional difficulties in prison including the ambiguous status of a pregnant prisoner, physical aspects of pregnancy and the degradation of the handcuffed or chained prisoner during visits to the more public setting of hospital. This article draws on Erving Goffman's concepts of closed institutions, dramaturgy and mortification of self, Crewe et al.'s work on the gendered pains of imprisonment and Crawley's notion of ‘institutional thoughtlessness’, and proposes a new concept of institutional ignominy to understand the embodied situation of the pregnant prisoner.Peer reviewe

Critical Exponent for the Density of Percolating Flux

This paper is a study of some of the critical properties of a simple model for flux. The model is motivated by gauge theory and is equivalent to the Ising model in three dimensions. The phase with condensed flux is studied. This is the ordered phase of the Ising model and the high temperature, deconfined phase of the gauge theory. The flux picture will be used in this phase. Near the transition, the density is low enough so that flux variables remain useful. There is a finite density of finite flux clusters on both sides of the phase transition. In the deconfined phase, there is also an infinite, percolating network of flux with a density that vanishes as $T \rightarrow T_{c}^{+}$. On both sides of the critical point, the nonanalyticity in the total flux density is characterized by the exponent $(1-\alpha)$. The main result of this paper is a calculation of the critical exponent for the percolating network. The exponent for the density of the percolating cluster is $\zeta = (1-\alpha) - (\varphi-1)$. The specific heat exponent $\alpha$ and the crossover exponent $\varphi$ can be computed in the $\epsilon$-expansion. Since $\zeta < (1-\alpha)$, the variation in the separate densities is much more rapid than that of the total. Flux is moving from the infinite cluster to the finite clusters much more rapidly than the total density is decreasing.Comment: 20 pages, no figures, Latex/Revtex 3, UCD-93-2

Wearing body cameras increases assaults against officers and does not reduce police use of force: Results from a global multi-site experiment

Police use of force is at the forefront of public awareness in many countries. Body-worn videos (BWVs) have been proposed as a new way of reducing police use of force, as well as assaults against officers. To date, only a handful of peer-reviewed randomised trials have looked at the effectiveness of BWVs, primarily focusing on use of force and complaints. We sought to replicate these studies, adding assaults against police officers as an additional outcome. Using a prospective meta-analysis of multi-site, multi-national randomised controlled trials from 10 discrete tests with a total population of +2 million, and 2.2 million police officer-hours, we assess the effect of BWVs on the rates of (i) police use of force and (ii) assaults against officers. Averaged over 10 trials, BWVs had no effect on police use of force ( d = 0.021; SE = 0.056; 95% CI: –0.089–0.130), but led to an increased rate of assaults against officers wearing cameras (d = 0.176; SE = 0.058; 95% CI: 0.061–0.290). As there is evidence that cameras may increase the risk of assaults against officers, more attention should be paid to how these devices are implemented. Likewise, since other public-facing organisations are considering equipping their staff with BWVs (e.g. firefighters, private security, traffic wardens), the findings on risks associated with BWVs are transferrable to those occupations as well. This is the final version of the article. It first appeared from Sage via https://doi.org/10.1177/1477370816643734

Complex-Temperature Singularities in the d=2d=2 Ising Model. III. Honeycomb Lattice

We study complex-temperature properties of the uniform and staggered susceptibilities $\chi$ and $\chi^{(a)}$ of the Ising model on the honeycomb lattice. From an analysis of low-temperature series expansions, we find evidence that $\chi$ and $\chi^{(a)}$ both have divergent singularities at the point $z=-1 \equiv z_{\ell}$ (where $z=e^{-2K}$), with exponents $\gamma_{\ell}'= \gamma_{\ell,a}'=5/2$. The critical amplitudes at this singularity are calculated. Using exact results, we extract the behaviour of the magnetisation $M$ and specific heat $C$ at complex-temperature singularities. We find that, in addition to its zero at the physical critical point, $M$ diverges at $z=-1$ with exponent $\beta_{\ell}=-1/4$, vanishes continuously at $z=\pm i$ with exponent $\beta_s=3/8$, and vanishes discontinuously elsewhere along the boundary of the complex-temperature ferromagnetic phase. $C$ diverges at $z=-1$ with exponent $\alpha_{\ell}'=2$ and at $v=\pm i/\sqrt{3}$ (where $v = \tanh K$) with exponent $\alpha_e=1$, and diverges logarithmically at $z=\pm i$. We find that the exponent relation $\alpha'+2\beta+\gamma'=2$ is violated at $z=-1$; the right-hand side is 4 rather than 2. The connections of these results with complex-temperature properties of the Ising model on the triangular lattice are discussed.Comment: 22 pages, latex, figures appended after the end of the text as a compressed, uuencoded postscript fil

The Gibbs-Thomson formula at small island sizes - corrections for high vapour densities

In this paper we report simulation studies of equilibrium features, namely circular islands on model surfaces, using Monte-Carlo methods. In particular, we are interested in studying the relationship between the density of vapour around a curved island and its curvature-the Gibbs-Thomson formula. Numerical simulations of a lattice gas model, performed for various sizes of islands, don't fit very well to the Gibbs-Thomson formula. We show how corrections to this form arise at high vapour densities, wherein a knowledge of the exact equation of state (as opposed to the ideal gas approximation) is necessary to predict this relationship. Exploiting a mapping of the lattice gas to the Ising model one can compute the corrections to the Gibbs-Thomson formula using high field series expansions. We also investigate finite size effects on the stability of the islands both theoretically and through simulations. Finally the simulations are used to study the microscopic origins of the Gibbs-Thomson formula. A heuristic argument is suggested in which it is partially attributed to geometric constraints on the island edge.Comment: 27 pages including 7 figures, tarred, gzipped and uuencoded. Prepared using revtex and espf.sty. To appear in Phys. Rev.