Collision damping in the pi 3He -> d'N reaction near the threshold

We present a simple quantum mechanical model exploiting the optical potential approach for the description of collision damping in the reaction pi 3He -> d'N near the threshold, which recently has been measured at TRIUMF. The influence of the open d'N -> NNN channel is taken into account. It leads to a suppression factor of about ten in the d' survival probability. Applications of the method to other reactions are outlined.Comment: RevTeX4, 14 pages, 3 Postscript figures, uses epsfig.sty, to appear in Phys.Rev.

Caspar Schwenckfeld’s Commentary on the Augsburg Confession: A Translation and Critical Introduction

The purpose of this thesis is to present a scholarly English translation, with appropriate background matter and historico-theological material, of Caspar von Schwenckfeld’s Commentary on the Augsburg Confession, written sometime during or after Autumn, 1531. There is a brief biographical chapter, as well as short chapters on Schwenckfeld’s relationship with Luther and Melanchthon, and a synopsis of Schwenckfeld’s theology, with special emphasis on themes presented in this Commentary (religious liberty, concept of the Church). The text of Document 103 of the Corpus Schwenckfeldianorum (Vol. III, pp. 862-940, No. 58 in the so-called “P” Epistolar) is translated with notes and comments. Three appendices are added to round out the thesis: 1. Paul Gerhard Eberlein’s article “Schwenckfelds Urteil über die Augsburger Confession,” from the Jahrbuch für schlesishe Kirche und Kirchengeschichte (1955), p. 53-63, is translated into English for the first time. 2. An excerpt from Christian August Salig’s Vollständige Historie der Augsburgischen Confession (Bd. III, pp. 984-8) is also translated for the first time. 3. A brief consideration of Schwenckfeld’s use of St. John Chrysostom is added to conclude the presentation

Heisenberg frustrated magnets: a nonperturbative approach

Frustrated magnets are a notorious example where the usual perturbative methods are in conflict. Using a nonperturbative Wilson-like approach, we get a coherent picture of the physics of Heisenberg frustrated magnets everywhere between $d=2$ and $d=4$. We recover all known perturbative results in a single framework and find the transition to be weakly first order in $d=3$. We compute effective exponents in good agreement with numerical and experimental data.Comment: 5 pages, Revtex, technical details available at http://www.lpthe.jussieu.fr/~tissie

Pion double charge exchange on 4He

The doubly differential cross sections for the $^4$He$(\pi^+,\pi^-) 4p$ reaction were calculated using both a two-nucleon sequential single charge exchange model and an intranuclear cascade code. Final state interactions between the two final protons which were the initial neutrons were included in both methods. At incident pion energies of 240 and 270 MeV the low-energy peak observed experimentally in the energy spectrum of the final pions can be understood only if the contribution of pion production is included. The calculated cross sections are compared with data.Comment: 25 pages, 9 figure

Optimization of the derivative expansion in the nonperturbative renormalization group

We study the optimization of nonperturbative renormalization group equations truncated both in fields and derivatives. On the example of the Ising model in three dimensions, we show that the Principle of Minimal Sensitivity can be unambiguously implemented at order $\partial^2$ of the derivative expansion. This approach allows us to select optimized cut-off functions and to improve the accuracy of the critical exponents $\nu$ and $\eta$. The convergence of the field expansion is also analyzed. We show in particular that its optimization does not coincide with optimization of the accuracy of the critical exponents.Comment: 13 pages, 9 PS figures, published versio

A non perturbative approach of the principal chiral model between two and four dimensions

We investigate the principal chiral model between two and four dimensions by means of a non perturbative Wilson-like renormalization group equation. We are thus able to follow the evolution of the effective coupling constants within this whole range of dimensions without having recourse to any kind of small parameter expansion. This allows us to identify its three dimensional critical physics and to solve the long-standing discrepancy between the different perturbative approaches that characterizes the class of models to which the principal chiral model belongs.Comment: 5 pages, 1 figure, Revte

Few-body resonances in light nuclei

We have localized several few-body resonances in light nuclei, using methods which can properly handle two- or three-body resonant states. Among other results, we predict the existence of a three-neutron resonance, small spin-orbit splittings between the low-lying states in He-5 and Li-5, the nonexistence of the soft dipole resonance in He-6, new 1+ states in Li-8 and B-8, and the presence of a nonlinear amplification phenomenon in the 0+_2 state of C-12

The strategic economic governance of Greater Manchester's local labour market by the local state: implications for young workers

This article explores how work and employment conditions for young workers are affected by the actions of the state at the spatial scale of the locality. The article argues that young workers have experienced deteriorating labour market conditions following shifts in the form which capitalist accumulation takes in the UK. This shift has altered the composition of the national state which has in turn led to changes in how it regulates both local labour markets and the economic strategies of the local state. One result of these changes is the diffusion of neoliberal labour market reforms which have led to negative material consequences for young workers; these are manifest in the expansion of low-waged work concentrated in a small number of sectors, and characterized by an intensified labour process

Structure and mechanism of the reversible photoswitch of a fluorescent protein

Proteins that can be reversibly photoswitched between a fluorescent and a nonfluorescent state bear enormous potential in diverse fields, such as data storage, in vivo protein tracking, and subdiffraction resolution light microscopy. However, these proteins could hitherto not live up to their full potential because the molecular switching mechanism is not resolved. Here, we clarify the molecular photoswitching mechanism of asFP595, a green fluorescent protein (GFP)-like protein that can be transferred from a nonfluorescent "off" to a fluorescent "on" state and back again, by green and blue light, respectively. To this end, we establish reversible photoswitching of fluorescence in whole protein crystals and show that the switching kinetics in the crystal is identical with that in solution. Subsequent x-ray analysis demonstrated that upon the absorption of a green photon, the chromophore isomerizes from a trans (off) to a cis (on) state. Molecular dynamics calculations suggest that isomerization occurs through a bottom hula twist mechanism with concomitant rotation of both bonds of the chromophoric methine ring bridge. This insight into the switching mechanism should facilitate the targeted design of photoswitchable proteins. Reversible photoswitching of the protein chromophore system within intact crystals also constitutes a step toward the use of fluorescent proteins in three-dimensional data recording

Glacier outflow dissolved organic matter as a window into seasonally changing carbon sources: Leverett Glacier, Greenland

The Greenland Ice Sheet is losing mass at a remarkable rate as a result of climatic warming. This mass loss coincides with the export of dissolved organic matter (DOM) in glacial meltwaters. However, little is known about how the source and composition of exported DOM changes over the melt season, which is key for understanding its fate in downstream ecosystems. Over the 2015 ablation season, we sampled the outflow of Leverett Glacier, a large land‐terminating glacier of the Greenland Ice Sheet. Dissolved organic carbon (DOC) concentrations and DOM fluorescence were analyzed to assess the evolution of DOM sources over the course of the melt season. DOC concentrations and red‐shifted fluorescence were highly associated (R2 > 0.95) and suggest terrestrial inputs from overridden soils dominated DOM early season inputs before progressive dilution with increasing discharge. During the outburst period, supraglacial drainage events disrupted the subglacial drainage system and introduced dominant protein‐like fluorescence signatures not observed in basal flow. These results suggest that subglacial hydrology and changing water sources influence exported DOC concentration and DOM composition, and these sources were differentiated using fluorescence characteristics. Red‐shifted fluorescence components were robust proxies for DOC concentration. Finally, the majority of DOM flux, which occurs during the outburst and postoutburst periods, was characterized by protein‐like fluorescence from supraglacial and potentially subglacial microbial sources. As protein‐like fluorescence is linked to the bioavailability of DOM, the observed changes likely reflect seasonal variations in the impact of glacial inputs on secondary production in downstream ecosystems due to shifting hydrologic regimes