Influence of single-neutron stripping on near-barrier ⁶He+²⁰⁸Pb and ⁸He+²⁰⁸Pb elastic scattering

The influence of single-neutron stripping on the near-barrier elastic scattering angular distributions for the 6,8He+208Pb systems is investigated through coupled reaction channels (CRC) calculations fitting recently published data to explore the differences in the absorptive potential found in the scattering of these two neutron-rich nuclei. The inclusion of the coupling reduces the elastic cross section in the Coulomb-nuclear interference region for 8He scattering, whereas for 6He its major impact is on the large-angle elastic scattering. The real and imaginary dynamic polarization potentials are obtained by inverting the CRC elastic scattering S-matrix elements. These show that the main absorptive features occur between 11 and 12 fm for both projectiles, while the attractive features are separated by about 1 fm, with their main structures occurring at 10.5 fm for 6He and 11.5 fm for 8He

Using environmental DNA for detection of Batrachochytrium salamandrivorans in natural water

Rapid, early, and reliable detection of invasive pathogenic microorganisms is essential in order to either predict or delineate an outbreak, and monitor appropriate mitigation measures. The chytrid fungus Batrachochytrium salamandrivorans is expanding in Europe, and infection with this fungus may cause massive mortality in urodelans (salamanders and newts). In this study, we designed and validated species‐specific primers and a probe for detection of B. salamandrivorans in water. In a garden pond in close proximity to the B. salamandrivorans index site in the Netherlands, B. salamandrivorans‐infected newts had been detected in 2015 and have been monitored since. In 2016 and 2017, no B. salamandrivorans was detected at this site, but in 2018 B. salamandrivorans flared up in this isolated pond which allowed validation of the technique in situ. We here present the development of an environmental DNA technique that successfully detects B. salamandrivorans DNA in natural waterbodies even at low concentrations. This technique may be further validated to play a role in B. salamandrivorans range delineation and surveillance in both natural waterbodies and in captive collections

Three-body continuum-discretized coupled-channel calculations for 6 He scattering from heavy nuclei

ata for scattering of 6He from 197Au, 208Pb, and 209Bi targets at low energies were consistently analyzed by use of the continuum-discretized coupled-channels method and the dineutron model of the projectile. A very good description of the experimental data was obtained with the strength of the dipole couplings reduced by 50%. We find that the dipole couplings are responsible for the suppression of the Coulomb rainbow and that the quadrupole couplings must be included in the calculations in order to obtain good agreement with the elastic-scattering data at more backward angles.Ministerio de Ciencia y Tecnología FPA2003-05958 FPA2005-0446

Multi-neutron transfer in 8^{8}He induced reactions near the Coulomb barrier

The measured inclusive $^6$He and $^4$He production cross sections of G. Marqu{\'i}nez-Dur{\'a}n {\em et al.}, Phys.\ Rev.\ C {\bf 98}, 034615 (2018) are reexamined and the conclusions concerning the relative importance of 1n and 2n transfer to the production of $^6$He arising from the interaction of a 22 MeV $^8$He beam with a $^{208}$Pb target revised. A consideration of the kinematics of the 2n-stripping reaction when compared with the measured $^6$He total energy versus angle spectrum places strict limits on the allowed excitation energy of the $^{210}$Pb residual, so constraining distorted wave Born approximation calculations that the contribution of the 2n stripping process to the inclusive $^6$He production can only be relatively small. It is therefore concluded that the dominant $^6$He production mechanism must be 1n stripping followed by decay of the $^7$He ejectile. Based on this result we present strong arguments in favor of direct, one step four-neutron (4n) stripping as the main mechanism for $^4$He production.Comment: 7 pages, 2 figure

Working Overtime: Multiple-Office Holding in New Jersey

The residents of Union City, NJ— a 1.2 square mile metropolis across the Hudson from Manhattan—are fond of taking to the task of adorning their city streets on their own. In the business sector of the city (that is to say, most of it) the business owners garnish their windows with red, white, and blue, and more often than not their decoration is accompanied by the uncomfortably warm smile of a middle-aged bespectacled Irish man. The man, so comically out of place in the majority Spanish-speaking, 82.3% Latino city, is referred to interchangeably as Mayor and State Senator Brian P. Stack. On the city’s border is official proof of his status on the “Welcome to Union City” sign, mirrored by its North Bergen, NJ counterpart and the name Nicholas Sacco: mayor, state senator, assistant superintendent of North Bergen schools, and principal of Horace Mann Elementary. For decades, New Jersey politicians have viewed multiple office holding as an integral part of the urban power structure. To rise up in the totem pole, one must collect public office jobs until rising to one high enough to stand on its own. While not particularly common in the less populated areas of the state, urban centers like the aforementioned Hudson County, Newark, and Camden have a tradition of sending their leaders off to Trenton without making them relinquish their jobs at home. And yet it was these very state legislators that passed a ban on the practice into law in February 2008. Supported by senator-turned-governor Jon Corzine, the ban passed with the support of political leaders like Stack and Sacco. On paper and in the pages of the New York Times it read like a rare and barely believable victory for political morality in what longtime NJ political journalists Bob Ingle and Sandy McClure call “The Soprano State”. If it sounded barely believable, it is probably because in practice it was not. A grandfather clause in the law keeps those currently in two positions of power safe from the wrath of the law. And since elections were held in between the passing of the law and the enacting of it, there are actually more dual office holders in the Legislature today than there were when the law was passed according to state newspaper the Star Ledger. This study intends answer several questions regarding the phenomenon of multiple office holding and its sudden “extinction” in New Jersey. I hypothesize that the introduction of such a law was merely cashing in on a long-standing bit of political credit that, due to the highly salient role of the practice in building machines, could not be touched. As the number of political bosses engaging in this practice diminished, and as the need to hold various offices lessened because of an increase in income and power from other sources, dual office holding became an obsolete relic of the 1990s political machine structures. Thus it became feasible to ban the practice with a grandfather clause for those that had established themselves through this old system, with much credit in the field of ethics to be gained by all involved—every dual office holder, legislator, and the governor himself. On a micro level, it aspires to investigate why early 2008 was an opportune time for such a law and where this grandfather clause arouse from and why. Although the tradition has existed previously in less populated areas of New Jersey, especially in the 1940s, at some point (peaking in the 1990s) dual office holding became an essential component in the structure of an urban political machine. On a macro level, this study seeks to explain the place of such a practice in the creation and maintenance of the traditional urban political machine, a structure with a lush history in New Jersey that is still alive and kicking today. It attempts to begin a dialogue with existing literature on urban politics centered around the practice of dual office holding. To do this, the study needs to paint as vivid a portrait as possible of the modern urban political machine, its bosses, and every gear that moves its structure. For this it will heavily rely on literature describing the initial development of political machines of Tammany Hall and similar structures around the country, paying especial attention to the impact of immigration, given that preliminary research is showing a pronounced impact on the system from the wave of Latino immigrants beginning with the rise of the Cuban Revolution in 1958. This new wave of immigrants appears to have jump-started the machines and replenished them with an entire new wave of fodder ready to be introduced to the patronage system post-naturalization (a matter of five years’ time). Of particular note in this body of urban political research is Steven Erie’s Rainbow’s End, which I have discovered to be the definitive work in the field of immigration and its impact on urban political machines. Working with this broad field of urban politics in mind, I also intend on illustrating in detail the specific political machine structures of the three largest urban communities in New Jersey: Newark, Camden, and the general Hudson County area (as the cities of Hudson County tend to be about 1-2 square miles in area excepting Jersey City, there is little that distinguishes one from another culturally and politically). In order to do this, I must work with data specific to the state, beginning with a database of multiple office holders over time. I have constructed this database over the course of several decades and am currently developing it in the 1930s using biographical sketches in the New Jersey Legislative Manuals published yearly in the New Jersey State Archives of Trenton. Unfortunately, this means that my research is limited to multiple office holders who have one job in the state legislature, but as all signs point to most dual office holders preferring to have a state and local job rather than two of either, I do not believe this will seriously hinder my research. Supplementary research will also come from personal stories, which I plan on gathering from interviews with those deeply involved in urban politics. The study will include interviews with multiple office holders from these regions themselves, as well as those close to them—journalists, chiefs of staff, and those receiving patronage and practicing loyalty to the leaders. The goal of this study is to shed some light on the dark, backroom world of urban politics through the lens of this one common practice among the machine leaders. This one practice, currently a topic of much controversy due to this recent law, could very well be the key to understanding the development of machines, their power over citizens and their ability to maintain themselves over such extended periods of time

Elastic Scattering of 6He on Heavy Targets at Coulomb Barrier Energies

Elastic cross sections for the scattering of 6He projectiles by 208Pb at 27 MeV have been studied. The data have been analyzed within the framework of the Optical Model using Saxon–Woods phenomenological form factors for both the real and imaginary parts of the nuclear potential. The elastic scattering data suggests the presence of a long range absorption mechanisms which might be related to the halo structure of 6He.Ministerio Ciencia y Tecnología FPA2002-04181- C04-04 y FPA2000-1592-C03-0

Reorientation and coupling effects in polarized heavy ion fusion

A simple model to understand the reaction mechanisms in the fusion of polarized heavy ions based on tidal symmetry, the sudden approximation and barrier penetration is presented. The model is applied to 23Na+208Pb. The effect of the ground state reorientation and the coupling to rotational states is studied. Enhancement of the sub-barrier fusion cross sections and the fusion J-moments just above the barrier are found. The polarization of the projectile affects strongly the fusion around and below the Coulomb barrier.Dirección General de Investigaciones Científicas y Técnicas PB89-063

Positron-neutrino correlations in 32Ar and 33Ar Decays: Probes of Scalar weak currents and nuclear isospin mixing

The positron-neutrino correlation in the 0^+ \to 0^+ \beta decay of ^{32}Ar was measured at ISOLDE by analyzing the effect of lepton recoil on the shape of the narrow proton group following the superallowed decay. Our result is consistent with the Standard Model prediction; for vanishing Fierz interference we find a=0.9989 \pm 0.0052 \pm 0.0036. Our result leads to improved constraints on scalar weak interactions. The positron-neutrino correlation in ^{33}Ar decay was measured in the same experiment; for vanishing Fierz interference we find a=0.944 \pm 0.002 \pm 0.003. The ^{32}Ar and ^{33}Ar correlations, in combination with precision measurements of the half-lives, superallowed branching ratios and beta endpoint energies, will determine the isospin impurities of the superallowed transitions. These will provide useful tests of isospin-violation corrections used in deducing |V_{\rm ud}| which currently indicates non-unitarity of the KM matrix.Comment: 15 pages, 6 figure

Finite size effects near the onset of the oscillatory instability

A system of two complex Ginzburg - Landau equations is considered that applies at the onset of the oscillatory instability in spatial domains whose size is large (but finite) in one direction; the dependent variables are the slowly modulated complex amplitudes of two counterpropagating wavetrains. In order to obtain a well posed problem, four boundary conditions must be imposed at the boundaries. Two of them were already known, and the other two are first derived in this paper. In the generic case when the group velocity is of order unity, the resulting problem has terms that are not of the same order of magnitude. This fact allows us to consider two distinguished limits and to derive two associated (simpler) sub-models, that are briefly discussed. Our results predict quite a rich variety of complex dynamics that is due to both the modulational instability and finite size effects