Deformation versus Sphericity in the Ground States of the Lightest Gold Isotopes.

The changes in mean-squared charge radii of neutron-deficient gold nuclei have been determined using the in-source, resonance-ionization laser spectroscopy technique, at the ISOLDE facility (CERN). From these new data, nuclear deformations are inferred, revealing a competition between deformed and spherical configurations. The isotopes ^{180,181,182}Au are observed to possess well-deformed ground states and, when moving to lighter masses, a sudden transition to near-spherical shapes is seen in the extremely neutron-deficient nuclides, ^{176,177,179}Au. A case of shape coexistence and shape staggering is identified in ^{178}Au which has a ground and isomeric state with different deformations. These new data reveal a pattern in ground-state deformation unique to the gold isotopes, whereby, when moving from the heavy to light masses, a plateau of well-deformed isotopes exists around the neutron midshell, flanked by near-spherical shapes in the heavier and lighter isotopes-a trend hitherto unseen elsewhere in the nuclear chart. The experimental charge radii are compared to those from Hartree-Fock-Bogoliubov calculations using the D1M Gogny interaction and configuration mixing between states of different deformation. The calculations are constrained by the known spins, parities, and magnetic moments of the ground states in gold nuclei and show a good agreement with the experimental results.

Evaluation of oxytetracycline leaching from pregelatinized starch-coated medicated fish feed.

The rapid growth and intensification of aquaculture industries have led to an increased use of antibiotics. Consequently, growing concerns have mounted over the environmental contamination of these drugs from medicated feeds and the risk that this poses for antimicrobial resistance. To circumvent environmental leaching, farmers topcoat medicated feeds with oil; however, this only partially addresses the issue. This study investigated the potential of food-grade pregelatinized corn starch (PGS) as a second top-coating agent to reduce oxytetracycline (OTC) leaching from the hand-mixed medicated feed. We immersed top-coated medicated feeds for different periods of time and measured the concentration of OTC in the water to determine leaching. We found a significantly lower level of OTC in water samples collected from the PGS-coated medicated feed compared to the non-PGS-coated medicated feed, with concentrations of OTC approximately 4 and 2.6 times the latter after 5 min and 2 h of water immersion, respectively. We also fed PGS-coated antibiotic feed to jade perch to determine if fish accepted the top-coating and whether they absorbed the OTC. Results from a feeding trial suggested no difference in palatability between PGS and non-PGS-coated medicated feed. We also found that muscle tissue from fish fed with the aforementioned diets had similar levels of OTC concentrations, suggesting that PGS coating does not alter the gastrointestinal absorption of this medication. From our experiment, we conclude that PGS is potentially a new top-coating agent to reduce leaching in hand-mixed OTC medicated feed.

Analysis of the interrelationships of stakeholders involved in the management of transhumance in southern Benin.

The management of pastoral mobility is a stakeholder-centered approach for the integration of resource conservation and agricultural development. This study aimed to characterize the stakeholders of transhumance and to analyze their influence in the municipality of Djidja in southern Benin. For this purpose, semi-structured interviews were conducted with 300 stakeholders involved in transhumance and pastoral resource management. The Likert scale (1 to 5) was used to assess the levels of influence and focus groups were conducted. The results showed that several stakeholders (transhumant herders, agro-pastoralists, farmers, hunters, fishermen, loggers, gendarmerie, Garso, CTAF, cattle farmers' associations, farmers' associations, SCDA, and communal transhumance committee) were involved in transhumance with diverse interests, backgrounds, knowledge, and power (P < 0.05). More than half of the farmers (72%) blame transhumant herders whose practices are source of multiple conflicts among (please mention what kind of conflicts and with whom by providing example). Statistical analysis indicated a strong influence with significant differences (P < 0.001) in the pastoral resources by four stakeholders including the communal transhumance committee, the association of herders, the Garso (scout and intermediary for transhumant herders), and the transhumant herder. This research demonstrates how the systematic analysis of the activities carried out by the stakeholders, the interconnected activities between them, and their relationships can offer insights for a better coordination of transhumance. For effective pastoral management, it is therefore important to build a dialogue between the different stakeholders involved in transhumance in southern Benin.

Large Shape Staggering in Neutron-Deficient Bi Isotopes.

The changes in the mean-square charge radius (relative to ^{209}Bi), magnetic dipole, and electric quadrupole moments of ^{187,188,189,191}Bi were measured using the in-source resonance-ionization spectroscopy technique at ISOLDE (CERN). A large staggering in radii was found in ^{187,188,189}Bi^{g}, manifested by a sharp radius increase for the ground state of ^{188}Bi relative to the neighboring ^{187,189}Bi^{g}. A large isomer shift was also observed for ^{188}Bi^{m}. Both effects happen at the same neutron number, N=105, where the shape staggering and a similar isomer shift were observed in the mercury isotopes. Experimental results are reproduced by mean-field calculations where the ground or isomeric states were identified by the blocked quasiparticle configuration compatible with the observed spin, parity, and magnetic moment.

Towards community-based in situ conservation strategies: a typological analysis of Borgou cattle herding systems in northeastern Benin.

A thorough knowledge of cattle herding systems is very important for planning sustainable genetic improvement and conservation strategies. This paper is initiated to characterize Benin native Borgou cattle farming systems in its department of origin by mean of survey including 180 cattle farmers owning at least one phenotype of that breed. Using multiple correspondence analysis and hierarchical ascending classification, four groups of Borgou cattle farms have been identified. The first group qualified as "semi-intensive purebred Borgou cattle farming" own high numbers (87.2 ± 3.95 heads) purchased and reared with the view to promote its genetic improvement, its production, and its conservation as Benin animal genetic resource. The second group (sedentary purebred Borgou cattle farming) is represented by Bariba ethnic group with small numbers (22.18 ± 0.71 heads) of purebred Borgou cattle used mainly for draught. Cattle farmers of the third group are "large transhumant of Zebu and Borgou crossbred cattle farmers" represented by Fulani and Gando ethnic groups whose herds are generally composed of high numbers (75.20 ± 3.43 heads) of cattle acquired by purchasing, inheriting, and fostering. The last one is the "small transhumant of Zebu and Borgou crossbred cattle farming" with an average herd size of 31.98 ± 0.72 heads. Cattle farming is their main activity and animals are used for the production of milk and cheese. These distinctions between Borgou cattle farmers can be an anchorage point for designing sustainable community-based in situ conservation strategies for safeguarding this local breed in its original cradle.

Tool for predicting Caligus rogercresseyi abundance on salt water salmon farms in Chile.

Caligus rogercresseyi is a host-dependent parasite that affects rainbow trout and Atlantic salmon in Chile. Numbers of sea lice on fish increase over time at relatively predictable rates when the environment is conducive to the parasite's survival and fish are not undergoing treatment. We developed a tool for the salmon industry in Chile that predicts the abundance of adult sea lice over time on farms that are relatively isolated. We used data on sea louse abundance collected through the SalmonChile INTESAL sea lice monitoring program to create series of weekly lice counts between lice treatment events on isolated farms. We defined isolated farms as those with no known neighbors within a 10 km seaway distance and no more than two neighbors within a 20 km seaway distance. We defined the time between sea lice treatments as starting the week immediately post treatment and ending the week before a subsequent treatment. Our final dataset of isolated farms consisted of 65 series from 32 farms, between 2009 and 2015. Given an observed abundance at time t = 0, we built a model that predicted 8 consecutive weekly sea louse abundance levels, based on the preceding week's lice prediction. We calibrated the parameters in our model on a randomly selected subset of training data, choosing the parameter combinations that minimized the absolute difference between the predicted and observed sea louse abundance values. We validated the parameters on the remaining, unseen, subset of data. We encoded our model and made it available as a Web-accessible applet for producers. We determined a threshold, based on the upper 97.5% predictive interval, as a guideline for producers using the tool. We hypothesize that if farms exceed this threshold, especially if the sea lice levels are above this threshold 2 and 4 weeks into the model predictions, the sea louse population on the farm is likely influenced by sources other than lice within the farm.

Assessing concentration of antibiotics in tissue during oral treatments against piscirickettsiosis.

The use of antimicrobials in aquaculture is increasingly being scrutinized. In Chile, piscirickettsiosis accounts for approximately 90% of the total volume of antibiotics used in marine aquaculture. Treatment failures are frequently reported, but there is limited information on why this occurs. Fish producers have started assessing the level of antibiotics in fish tissues during and immediately after in-feed treatments to determine if they are adequately medicating their fish. In this study, we evaluated the probability of finding antibiotic concentrations in muscle tissue above the minimum inhibitory concentration for 90% of the P. salmonis isolates (MIC90) recently tested in Chile, for two antibiotics commonly used in aquaculture. We found that the proportion of fish with antibiotic concentrations above the MIC90 varied, depending on the product used, species, day of sample collection, and size category of fish within a cage. The proportion of fish above the MIC90 was lower in fish treated with florfenicol than in fish treated with oxytetracycline. Using a mixed-effects logistic model, we modeled the probability of antibiotic concentrations above MIC90 when fish were treated with florfenicol. Our model suggested lower probabilities of having concentrations above MIC90 in Atlantic salmon than in rainbow trout when samples were collected 14 days after the treatment started compared to 7 days, and in the smaller fish within a cage. We discuss these findings and hypothesize about potential issues with treating large populations of fish with in-feed antimicrobials.

Evaluating the effect of synchronized sea lice treatments in Chile.

The sea louse is considered an important ectoparasite that affects farmed salmonids around the world. Sea lice control relies heavily on pharmacological treatments in several salmon-producing countries, including Chile. Among options for drug administration, immersion treatments represent the majority of antiparasitic control strategies used in Chile. As a topical procedure, immersion treatments do not induce a long lasting effect; therefore, re-infestation from neighbouring farms may undermine their efficacy. Synchronization of treatments has been proposed as a strategy to improve immersion treatment performance, but it has not been evaluated so far. Using a repeated-measures linear mixed-effect model, we evaluated the impact of treatment synchronization of neighbouring farms (within 10km seaway distance) on the adult lice mean abundance from weeks 2 to 8 post-treatment on rainbow trout and Atlantic salmon farms in Chile, while controlling for external and internal sources of lice before the treatments, and also for environmental and fish-related variables. Results indicate that treatment synchronization was significantly associated with lower adult lice levels from weeks 5 to 7 after treatment. This relationship appeared to be linear, suggesting that higher levels of synchronization may result in lower adult sea lice levels during these weeks. These findings suggest that synchronization can improve the performance of immersion delousing treatments by keeping sea lice levels low for a longer period of time. Our results may be applicable to other regions of the world where immersion treatments are widely used.

Erratum: Spectroscopic Quadrupole Moments in

This corrects the article DOI: 10.1103/PhysRevLett.116.022701.

Spectroscopic Quadrupole Moments in {96,98}Sr: Evidence for Shape Coexistence in Neutron-Rich Strontium Isotopes at N=60.

Neutron-rich {96,98}Sr isotopes have been investigated by safe Coulomb excitation of radioactive beams at the REX-ISOLDE facility. Reduced transition probabilities and spectroscopic quadrupole moments have been extracted from the differential Coulomb excitation cross sections. These results allow, for the first time, the drawing of definite conclusions about the shape coexistence of highly deformed prolate and spherical configurations. In particular, a very small mixing between the coexisting states is observed, contrary to other mass regions where strong mixing is present. Experimental results have been compared to beyond-mean-field calculations using the Gogny D1S interaction in a five-dimensional collective Hamiltonian formalism, which reproduce the shape change at N=60.

Understanding sources of sea lice for salmon farms in Chile.

The decline of fisheries over recent decades and a growing human population has coincided with an increase in aquaculture production. As farmed fish densities increase, so have their rates of infectious diseases, as predicted by the theory of density-dependent disease transmission. One of the pathogen that has increased with the growth of salmon farming is sea lice. Effective management of this pathogen requires an understanding of the spatial scale of transmission. We used a two-part multi-scale model to account for the zero-inflated data observed in weekly sea lice abundance levels on rainbow trout and Atlantic salmon farms in Chile, and to assess internal (farm) and external (regional) sources of sea lice infection. We observed that the level of juvenile sea lice was higher on farms that were closer to processing plants with fish holding facilities. Further, evidence for sea lice exposure from the surrounding area was supported by a strong positive correlation between the level of juvenile sea lice on a farm and the number of gravid females on neighboring farms within 30 km two weeks prior. The relationship between external sources of sea lice from neighboring farms and juvenile sea lice on a farm was one of the strongest detected in our multivariable model. Our findings suggest that the management of sea lice should be coordinated between farms and should include all farms and processing plants with holding facilities within a relatively large geographic area. Understanding the contribution of pathogens on a farm from different sources is an important step in developing effective control strategies.

Differential characterization of emerging skin diseases of rainbow trout--a standardized approach to capturing disease characteristics and development of case definitions.

Farmed and wild salmonids are affected by a variety of skin conditions, some of which have significant economic and welfare implications. In many cases, the causes are not well understood, and one example is cold water strawberry disease of rainbow trout, also called red mark syndrome, which has been recorded in the UK since 2003. To date, there are no internationally agreed methods for describing these conditions, which has caused confusion for farmers and health professionals, who are often unclear as to whether they are dealing with a new or a previously described condition. This has resulted, inevitably, in delays to both accurate diagnosis and effective treatment regimes. Here, we provide a standardized methodology for the description of skin conditions of rainbow trout of uncertain aetiology. We demonstrate how the approach can be used to develop case definitions, using coldwater strawberry disease as an example.

Antimicrobial use and resistance in aquaculture: findings of a globally administered survey of aquaculture-allied professionals.

There is limited published information regarding antimicrobial use (AMU) and antimicrobial resistance (AMR) in aquaculture. Our objective was to determine the opinions of aquaculture-allied professionals around the world on the frequency of AMU and AMR in common aquatic species. The study questionnaire included five sections: respondent demographics, extent of AMU in aquaculture, frequency of observations of AMR in aquaculture, AMR monitoring and surveillance and antimicrobial susceptibility testing in various jurisdictions. It was administered in English and Spanish to 604 professionals in 25 countries and with varying expertise in aquaculture. The response rate was 33% (199/604). Over half of the participants had >10 years of experience in aquaculture: 70% (140/199) were involved in fish health/clinical work and their primary experience was with salmon, tilapia, trout, shrimp (including prawn) and/or catfish. Tetracycline use was reported by 28%, 46%, 18%, 37% and 9% of respondents working with catfish, salmon, tilapia, trout and shrimp, respectively. Resistance to tetracycline in one or more species of bacteria was reported as 'frequent-to-almost always' for the same aquaculture species by 39%, 28%, 17%, 52% and 36% of respondents, respectively. 'Frequent-to-almost always' use of quinolone was reported by 70% (32/46) and 67% (8/12) of respondents from the United States and Canada, respectively, where quinolone products are not approved for aquaculture, and extra-label fluoroquinolone use is either prohibited (United States) or discouraged (Canada). Similar frequencies of quinolone use were also reported by the majority of respondents from Europe [70% (7/10)] and Asia [90% (9/10)] where labelled indications exist. This baseline information can be used to prioritize research or surveillance for AMU and AMR in aquaculture.

New fission fragment distributions and r-process origin of the rare-earth elements.

Neutron star (NS) merger ejecta offer a viable site for the production of heavy r-process elements with nuclear mass numbers A≳140. The crucial role of fission recycling is responsible for the robustness of this site against many astrophysical uncertainties, but calculations sensitively depend on nuclear physics. In particular, the fission fragment yields determine the creation of 110≲A≲170 nuclei. Here, we apply a new scission-point model, called SPY, to derive the fission fragment distribution (FFD) of all relevant neutron-rich, fissioning nuclei. The model predicts a doubly asymmetric FFD in the abundant A≃278 mass region that is responsible for the final recycling of the fissioning material. Using ejecta conditions based on relativistic NS merger calculations, we show that this specific FFD leads to a production of the A≃165 rare-earth peak that is nicely compatible with the abundance patterns in the Sun and metal-poor stars. This new finding further strengthens the case of NS mergers as possible dominant origin of r nuclei with A≳140.

Control of near-infrared supercontinuum bandwidth by adjusting pump pulse duration.

We experimentally and numerically investigated the impact of input pump pulse duration on the near-infrared bandwidth of supercontinuum generation in a photonic crystal fiber. We continuously stretched the temporal duration of the input pump laser (centered at 1030 nm) pulses from 500 fs up to 10 ps, while keeping fixed the pump peak power. We observed that the long-wavelength edge of the supercontinuum spectrum is increased by 200 nm as the pump pulse duration grows from 500 fs to 10 ps. We provide a quantitative fit of the experimental results by means of numerical simulations. Moreover, we have explained the observed spectral broadening enhancement induced by pump pulse energy by developing an approximate yet fully analytical model for soliton energy exchange through a series of collisions in the presence of stimulated Raman scattering.

Oral DNA vaccination of rainbow trout, Oncorhynchus mykiss (Walbaum), against infectious haematopoietic necrosis virus using PLGA [Poly(D,L-Lactic-Co-Glycolic Acid)] nanoparticles.

A DNA vaccine against infectious haematopoietic necrosis virus (IHNV) is effective at protecting rainbow trout, Oncorhynchus mykiss, against disease, but intramuscular injection is required and makes the vaccine impractical for use in the freshwater rainbow trout farming industry. Poly (D,L-lactic-co-glycolic acid) (PLGA) is a U.S. Food and Drug Administration (FDA) approved polymer that can be used to deliver DNA vaccines. We evaluated the in vivo absorption of PLGA nanoparticles containing coumarin-6 when added to a fish food pellet. We demonstrated that rainbow trout will eat PLGA nanoparticle coated feed and that these nanoparticles can be detected in the epithelial cells of the lower intestine within 96 h after feeding. We also detected low levels of gene expression and anti-IHNV neutralizing antibodies when fish were fed or intubated with PLGA nanoparticles containing IHNV G gene plasmid. A virus challenge evaluation suggested a slight increase in survival at 6 weeks post-vaccination in fish that received a high dose of the oral vaccine, but there was no difference when additional fish were challenged at 10 weeks post-vaccination. The results of this study suggest that it is possible to induce an immune response using an orally delivered DNA vaccine, but the current system needs improvement.

Parasites and hepatic lesions among pink salmon, Oncorhynchus gorbuscha (Walbaum), during early seawater residence.

Juvenile pink salmon, Oncorhynchus gorbuscha (Walbaum), in the Broughton Archipelago region of western Canada were surveyed over 2 years for sea lice (Lepeophtheirus salmonis and Caligus clemensi), gross and microscopic lesions and evidence of infections with viruses and bacteria. The 1071 fish examined had an approximate ocean residence time no longer than 3 months. A high prevalence of degenerative liver lesions, renal myxosporean parasites and a low prevalence of skin lesions and sea lice were observed. No indications of viral or bacterial diseases were detected in either year. The monthly prevalence of sea lice in 2007 (18-51%) was higher than in 2008 (1-26%), and the infestation density exceeded the lethal threshold in only two fish. Degenerative hepatic lesions and renal myxosporean parasites occurred in approximately 40% of the pink salmon examined in June of both years, and the peak monthly prevalence of hepatocellular hydropic degeneration was greater in 2007 (32%, in May) than in 2008 (12%, in June). Logistic regression analysis found skin lesions and hepatocellular hydropic degeneration significantly associated with sea lice. Most parasites and lesions occurred during both years, but the prevalence was often higher in 2007. Fish weight was 35% less in June 2007 than in June 2008, but condition factor was not different. Further research is required to monitor inter-annual variations and aetiology of the liver lesions and to assess their potential role on pink salmon survival.

First Gogny-Hartree-Fock-Bogoliubov nuclear mass model.

We present the first Gogny-Hartree-Fock-Bogoliubov (HFB) model which reproduces nuclear masses with an accuracy comparable with the best mass formulas. In contrast with the Skyrme-HFB nuclear-mass models, an explicit and self-consistent account of all the quadrupole correlation energies are included within the 5D collective Hamiltonian approach. The final rms deviation with respect to the 2149 measured masses is 798 keV. In addition, the new Gogny force is shown to predict nuclear and neutron matter properties in agreement with microscopic calculations based on realistic two- and three-body forces.

Antibody response of two populations of common carp, Cyprinus carpio L., exposed to koi herpesvirus.

Common carp, Cyprinus carpio L., exposed to koi herpesvirus (KHV) may become persistently infected and populations containing such virus-infected individuals may transmit the virus to other fish when co-habited. Detection of virus-infected fish in a population is thus critical to surveillance and control programmes for KHV. A study was therefore designed to detect anti-KHV serum antibodies, with an enzyme-linked immunosorbent assay, in common carp following experimental exposures to KHV under varying environmental conditions. The study determined that a proportion of fish within a population experimentally exposed to KHV (at least 10-25%) develop high antibody titres (1/1600 or greater) to the virus, and this immunological response was detectable for several months (observed at the termination of the experiments at 65, 46 and 27 weeks post-exposure). Furthermore, this response was detected in one population of fish that did not succumb to a high level of mortality when maintained at water temperatures that were non-permissive for KHV. Elevating the water temperatures to permissive conditions for KHV resulted in recurrence of disease despite the presence of anti-virus antibodies, suggesting that serum antibodies alone are not protective under the conditions of our trials.