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The concept of animal personality is based on consistent individual differences in behaviour, yet little is known about the factors responsible for such variation. Theory based on sex-specific selection predicts sexual dimorphism in personality-related traits and, in some cases, differences in trait variances between the sexes. In this study, we examined the sources of individual variation for boldness behaviour in guppies (Poecilia reticulata). We first demonstrated heightened boldness expression in males relative to females across feral wild types, artificially selected domestic ‘designer’ guppies, and putative hybrids of the two. Boldness and body size covaried at the strain level but were not associated among individuals within strains. We also found high and repeatable behavioural differences among individuals (0.40 > intraclass r > 0.60) in all sex/strain groups except hybrid strain females. However, there was no evidence for the heightened inter-individual male variance anticipated for personality traits subject to certain forms of directional sex-specific selection. Domestic fish were boldest overall, and indicated the largest sex difference, which is consistent with genetic linkage between boldness and male ornamental colouration. Consistently high intrinsic variation in boldness behaviour, which extends to inbred domesticated fish, may in part underpin the invasive potential of this species.

Little is known regarding the epidemiology and outcomes of patients with primary sclerosing cholangitis (PSC) in Australia. We, therefore, evaluated the epidemiology and clinical outcomes of PSC in a large cohort of Australian patients and compared these to the general population.We conducted a multicentre, retrospective cohort study of PSC patients at nine tertiary liver centers across three Australian states, including two liver transplant centers.A total of 413 PSC patients with 3,285 person-years of follow-up were included. Three hundred and seventy-one (90%) patients had large duct PSC and 294 (71%) had associated inflammatory bowel disease. A total of 168 (41%) patients developed cirrhosis (including 34 at the time of PSC diagnosis) after a median of 15.8 (95% CI 12.4, NA) years. The composite endpoint of death or liver transplantation occurred in 49 (12%) and 78 (19%) patients, respectively, with a median transplant-free survival of 13.4 (95% CI 12.2-15) years. Compared to the general population, PSC accounted for a 240-fold increased risk of development of cholangiocarcinoma (CCA) and CCA-related death. CCA risk was increased with older age of PSC diagnosis, presence of dominant stricture and colectomy. Compared to same-aged counterparts in the general population, PSC patients who were diagnosed at an older age or with longer disease duration had reduced relative survival.In this large retrospective cohort study of PSC patients in Australia, increased age and time from diagnosis was associated with increased mortality and morbidity particularly from CCA and development of cirrhosis, necessitating need for liver transplant.

In spite of the high-density and strongly correlated nature of the atomic nucleus, experimental and theoretical evidence suggests that around particular 'magic' numbers of nucleons, nuclear properties are governed by a single unpaired nucleon1,2. A microscopic understanding of the extent of this behaviour and its evolution in neutron-rich nuclei remains an open question in nuclear physics3-5. The indium isotopes are considered a textbook example of this phenomenon6, in which the constancy of their electromagnetic properties indicated that a single unpaired proton hole can provide the identity of a complex many-nucleon system6,7. Here we present precision laser spectroscopy measurements performed to investigate the validity of this simple single-particle picture. Observation of an abrupt change in the dipole moment at N = 82 indicates that, whereas the single-particle picture indeed dominates at neutron magic number N = 82 (refs. 2,8), it does not for previously studied isotopes. To investigate the microscopic origin of these observations, our work provides a combined effort with developments in two complementary nuclear many-body methods: ab initio valence-space in-medium similarity renormalization group and density functional theory (DFT). We find that the inclusion of time-symmetry-breaking mean fields is essential for a correct description of nuclear magnetic properties, which were previously poorly constrained. These experimental and theoretical findings are key to understanding how seemingly simple single-particle phenomena naturally emerge from complex interactions among protons and neutrons. ispartof: NATURE vol:607 issue:7918 pages:260-+ ispartof: location:England status: published

A study of the laser-ionized and mass-separated neutron-deficient isotopes Au 176 , 177 , 179 was performed using the Resonance Ionization Laser Ion Source and the Windmill detection setup at ISOLDE, CERN. New and improved data on complex fine-structure α decays of the three isotopes were deduced, providing insight into the low-lying levels in the daughter nuclei Ir 172 , 173 , 175 . New information on the properties of β -decay daughter products Pt 177 , 179 was also obtained. From the first in-source laser spectroscopy measurements of the hyperfine structure in the atomic 267.6-nm transition of Au 176 , the nuclear magnetic moments for both high- and low-spin α -decaying states were deduced. Together with the values determined from the additivity relations, they were used to propose the most probable spins and configurations for both states. The α -decay branching ratios were determined as b α ( Au ls 176 ) = 58 ( 5 ) % and b α ( Au hs 176 ) = 29 ( 5 ) % .

In spite of the high-density and strongly correlated nature of the atomic nucleus, experimental and theoretical evidence suggests that around particular 'magic' numbers of nucleons, nuclear properties are governed by a single unpaired nucleon

The potential of antiferroelectrics to exhibit a negative capacitance regime has been largely overlooked as all the attention focused on their polar counterparts, ferroelectrics. We use nonequilibrium first-principles-based molecular dynamics to probe a negative capacitance regime in prototypical antiferroelectric [Formula: see text]. Simulations predict that this antiferroelectric can exhibit a negative capacitance/susceptibility regime in response of polarization to an internal electric field, which is a superposition of applied and residual depolarizing fields. Consequently, the regime emerges when the polarization surface charge in the polar phase of antiferroelectric is not fully screened, as is often the case in thin films and nanostructures. The negative capacitance regime occurs below the Curie temperature and disappears in the paraelectric phase. We find that the time the material spends in the negative capacitance regime is proportional to the time needed to complete antipolar–polar (or its reverse) transition and shortens as the frequency of the applied field increases. Moreover, a negative susceptibility value exhibits strong dependence on the quality of surface charge screening with the largest in magnitude values occurring in the vicinity of the transition into a negative capacitance regime.

The Mu2e experiment at Fermilab will search for evidence of charged lepton flavor violation by observing the conversion of a negative muon into an electron in the Coulomb field of a nucleus without emission of neutrinos and will probe effective new-physics mass scales in the 103 􀀀 104 TeV range. One of the main parts of the Mu2e experimental setup is its target station in which negative pions are generated in interactions of the 8 GeV primary proton beam with a tungsten target, which will be capable of producing 2 1017 negative muons per year. Mu2e can be extended by a next generation experiment, Mu2e-II, with a sensitivity improved by another factor of 10 or more as enabled by the PIP-II accelerator upgrade project. PIP-II is a 250-meter-long linac capable of accelerating a 2 mA proton beam to a kinetic energy of 800 MeV corresponding to 1.6 MW of power. To achieve another factor of ten improvement in sensitivity, Mu2e-II will require about 100 kW of proton beam on target, and the added power requires a new target design. We will present our progress in RD of a target station conceptual design for Mu2e-II, using the MARS15 and G4beamline Monte-Carlo codes toward a selection between granular, conveyor, and rotating cylindrical target options.

This work advances laser absorption spectroscopy with measurements of aluminum monoxide (AlO) temperature and column density in extreme pressure (P > 60 bar) and temperature (T > 4000 K) environments. Measurements of the AlO A2Π i –X2Σ+ transition are made using a microelectromechanical system, tunable vertical cavity surface emitting laser (MEMS-VCSEL). Simultaneous emission measurements of the AlO B2Σ+–X2Σ+ transition are made along a line of sight that is coaxial with the laser absorption. Absorption temperature fits agree with emission spectra for a T = 3200 K, P = 9 bar case. In cases with T > 4000 K, P > 60 bar, absorption fits match the ambient temperature while emission fits over-estimate it, owing to high optical depths. These data juxtapose passive and active spectroscopic methods and demonstrate the versatility of AlO laser absorption in high-pressure and high-temperature environments where experimental data remain scarce, and engineering models will benefit from refined measurements.

Negative capacitance regime in ferroelectrics is associated with the negative slope in the dependence of the polarization on electric field and is prohibited by the laws of equilibrium thermodynamics. Very recently, it developed into a controversial but very productive area with a promise for next generation low-power transistors. At least, in part, the controversies arise from the lack of direct experimental insight into the mechanism for such phenomena. Although the experimental insight is, indeed, challenging at present, we probe the effect in ferroelectric $\mathrm{Pb}\mathrm{Ti}{\mathrm{O}}_{3}$ bulk and a thin film with realistic first-principles-based nonequilibrium molecular dynamics simulations which model most closely experimental conditions. The following insights emerge from the simulations: (i) the ferroelectric never enters the thermodynamically forbidden region even under extreme rates of electric-field application; (ii) the negative slope naturally arises when the compensating charge is either scarce or slowed down by the external circuitry; (iii) the negative slope is well controlled by the interplay between the applied step pulse field and the amount of the screening charge. The latter can be used to design the negative capacitance regime.

A study of the ground states of the laser-ionized and mass-separated odd-odd isotopes 180,182Au was performed using the Resonance Ionization Laser Ion Source, Windmill detection setup and ISOLTRAP Multi-Reflection Time-of-Flight Mass Spectrometer at ISOLDE, CERN. A complex fine-structure α-decay pattern of 180Au was deduced, providing insight into the low-lying levels in the daughter nucleus 176Ir. An α-decay branching ratio of bα(180Au)=0.58(10)% and a half-life of T1/2=7.2(5) s have also been derived, allowing for the calculation of the reduced α-decay widths and determining the degree of hindrance of respective α-decay branches. From complementary first in-source laser spectroscopy measurements of the hyperfine structure in atomic transitions of 180,182Au, the nuclear magnetic moments of μ(180Au)=−0.83(9)μN and μ(182Au)=1.66(9)μN were extracted with an inclusion of a correction for the hyperfine anomaly. Based on the observed hyperfine structure patterns, and on the comparison of the measured and calculated μ values, a preferred ground-state spin and parity Iπ(180Augs)=(1+) is proposed, and the earlier assignment of Iπ(182Augs)=(2+) is confirmed. For 180Au, the most probable proton-neutron Nilsson configuration of π3/2−[532]⊗ν5/2−[512] suggests the same proton state as in the heavier deformed odd-odd nuclei 182,184Au.

Density-functional-theory-based simulations are the leading tool for the computational investigation of ferroelectrics and the parametrization of their classical potentials. However, the predictions often depend strongly on the exchange-correlation functional. The most popular choices, the LDA and GGA, tend to underestimate or overestimate some structural, electric, and energy properties. These impede the development of highly accurate classical potentials that extend the reach of first-principles simulations to finite temperatures and realistic sizes. In this work, we investigate the performance of recently developed Minnesota exchange-correlation functionals on the prototypical ferroelectrics ${\mathrm{BaTiO}}_{3}$ and ${\mathrm{PbTiO}}_{3}$ in comparison with some popular ones. We find that there exists a strong correlation between predictions for some properties (tetragonality, phase energy difference, and polarization) by different functionals. Along the correlation line, we find a range of functionals (including some from the Minnesota suite) whose predictions fall between those of the LDA and those of the GGA and, therefore, offer an improvement. A way to relatively rank functional performance with respect to chosen benchmarks is proposed and applied to identify the top performers for ${\mathrm{BaTiO}}_{3}$ and ${\mathrm{PbTiO}}_{3}$. The performance is found to be material dependent. Therefore, we propose that the performance assessment carried out in this work is employed to ``screen'' functionals prior to their use on ferroelectrics. Quick and computationally inexpensive, it is likely to lead to improved descriptions, especially for classical potential parametrization. The Minnesota functional suite is found to be suitable for this task.

Hyperfine-structure constants for the 6s2S1/2 and 6p2P1/2 atomic states of the Iπ=11/2− gold isomers Aum177,191,193,195 have been measured at CERN-ISOLDE, using the in-source laser resonance-ionization spectroscopy technique. From the measured hyperfine constants the differences between hyperfine anomalies for these atomic states have been deduced. These differential hyperfine anomaly values have been used to determine the 6s-state hyperfine anomaly relative to the stable Au197 with advanced atomic calculations. Magnetic dipole moments for the gold isomers in question have been deduced, taking into account the corresponding relative hyperfine-anomaly values. It has been shown that the commonly used prescription for the extraction of the magnetic moment values for the gold isotopes should be reconsidered. The magnetic moments calculated by this prescription have been reevaluated by properly accounting for the hyperfine anomaly, which is as large as 10% for several gold isotopes.

A comprehensive study of the isotope 178Au has been made at the CERN-ISOLDE facility, using resonance laser ionization. Two long-lived states in 178Au were identified—a low-spin ground state and a high-spin isomer—each of which were produced as pure beams. Using the ISOLTRAP precision Penning trap, the excitation energy of the isomeric state in 178Au was determined to be E∗=189(14)keV. The α-decay fine structure patterns of the two states were studied using the Windmill decay station, providing information on the low-lying states in the daughter nucleus 174Ir. Nuclear spin assignments of I(178Aug)=(2,3) and I(178Aum)=(7,8) are made based on the observed β-decay feeding and hyperfine structure intensity patterns. These spin assignments are used for fitting the hyperfine structures of the two states from which values for the magnetic dipole moments are extracted. The extracted moments are compared with calculations using additivity relations to establish the most probable configurations for 178Aug,m.

The Mu2e Experiment at Fermilab will search for the coherent, neutrinoless conversion of a muon to an electron in the field of an atomic nucleus. Such charged lepton flavor violating events have never been observed, but are predicted to occur in many Beyond the Standard Model scenarios at rates accessible to our experiment. I outline the key accelerator issues for the experiment, our progress on design and construction to date, and schedule for the coming years.

We propose an evolution of the Mu2e experiment, called Mu2e-II, that would leverage advances in detector technology and utilize the increased proton intensity provided by the Fermilab PIP-II upgrade to improve the sensitivity for neutrinoless muon-to-electron conversion by one order of magnitude beyond the Mu2e experiment, providing the deepest probe of charged lepton flavor violation in the foreseeable future. Mu2e-II will use as much of the Mu2e infrastructure as possible, providing, where required, improvements to the Mu2e apparatus to accommodate the increased beam intensity and cope with the accompanying increase in backgrounds.

Nuclear spins and precise values of the magnetic dipole and electric quadrupole moments of the ground states of neutron-rich 73–78Cu isotopes were measured using the Collinear Resonance Ionization Spectroscopy (CRIS) experiment at the CERN On-Line Isotope Mass Separator (ISOLDE) facility. The nuclear moments of the less exotic 73,75Cu isotopes were remeasured with similar precision, yielding values that are consistent with earlier measurements. The moments of the odd-odd isotopes, and 78 29Cu (N =49) in particular, are used to investigate excitations of the assumed doubly magic 78Ni core through comparisons with large-scale shell-model calculations. Despite the narrowing of the Z =28 shell gap between N∼45 and N =50, the magicity of Z =28 and N =50 is restored toward 78Ni.This is due to weakened dynamical correlations, as clearly probed by the present moment measurements. ispartof: Physical Review C vol:96 issue:4 pages:1-6 status: published

Magnetic-dipole and electric-quadrupole moments for 65,67,69,75,79–82 Ga are reported using the Collinear Resonance Ionization Spectroscopy (CRIS) technique at the ISOLDE facility, CERN. The moments of 65 Ga have been measured for the first time: μ = +1.775(3) μ N and Qs = +21.0(15) efm 2 . These results are compared to shell-model calculations using the GXPF1 and JUN45 interactions and the trends of the moments approaching the region of the doubly magic 56 Ni are discussed. Additionally, new values for the change in mean-square charge radii for 65Ga and 67Ga allow investigation into the odd-even staggering in the region below N = 40. ispartof: Physical Review C vol:96 issue:4 pages:1-9 status: published

Hyperfine structure and isotope shifts have been measured for the ground and isomeric states in the neutron-deficient isotopes $^{179--184}\mathrm{Tl}$ using the 276.9-nm transition. The experiment has been performed at the CERN-Isotope Separator On-Line facility using the in-source resonance-ionization laser spectroscopy technique. Spins for the ground states in $^{179,181,183}\mathrm{Tl}$ have been determined as $I=1/2$. Magnetic moments and changes in the nuclear mean-square charge radii have been deduced. By applying the additivity relation for magnetic moments of the odd-odd Tl nuclei the leading configuration assignments were confirmed. A deviation of magnetic moments for isomeric states in $^{182,184}\mathrm{Tl}$ from the trend of the heavier Tl nuclei is observed. The charge radii of the ground states of the isotopes $^{179--184}\mathrm{Tl}$ follow the trend for isotonic (spherical) lead nuclei. The noticeable difference in charge radii for ground and isomeric states of $^{183,184}\mathrm{Tl}$ has been observed, suggesting a larger deformation for the intruder-based $9/{2}^{\ensuremath{-}}$ and ${10}^{\ensuremath{-}}$ states compared to the ground states. An unexpected growth of the isomer shift for $^{183}\mathrm{Tl}$ has been found.

Post-ash and post-etch cleaning of low-k structures require significant wetting of their surfaces. This work focuses on the interactions between dilute HF cleaning chemistries (dHF-1:50 to 1:1000) on porous low-k surfaces (k=2.3) as a function of time. Wetting of these solutions was measured by a contact angle goniometer within a high humidity environment. Because ashing low-k films can change their surface chemistry and structure, the contact angles of dHF on N"2/H"2 and O"2 ashed porous low-k films were measured as well. Ellipsometry has shown that 1:50 HF removes an ash-damaged layer from the low-k. Based on thickness loss measurements (ellipsometry and profilometry), the composition of the dilute HF droplet changes minimally as it etches the dielectric surface. Under more concentrated dHF solutions, changes in contact angle, droplet radius, and volume indicate that the droplet spreads for an initial period and then reaches a steady state, perhaps due to the creation of an etch inclusion on the surface. The steady state volume changes show volume loss rates similar to those expected from evaporation; however, the total volume losses are less than expected from only evaporative processes.

There is a tantalizing discrepancy between the Standard Model prediction for the muon g − 2 , and the value measured by the Brookhaven E821 Experiment. This discrepancy fairly begs for a new measurement. I will present the developing plans for improving on the Brookhaven experiment by a factor of four, to a combined uncertainty of 0.14ppm.

A compact and fast electromagnetic calorimeter prototype was designed, built, and tested in preparation for a next-generation, high-rate muon ( g − 2 ) experiment. It uses a simple assembly procedure: alternating layers of 0.5-mm-thick tungsten plates and 0.5-mm-diameter plastic scintillating fiber ribbons. This geometry leads to a detector having a calculated radiation length of 0.69 cm, a Moliere radius of 1.73 cm, and a measured intrinsic sampling resolution term of ( 11.8 ± 1.1 ) % / E ( GeV ) , in the range 1.5–3.5 GeV. The construction procedure, test beam results, and GEANT-4 comparative simulations are described.

We describe the data acquisition system for the MuLan muon lifetime experiment at Paul Scherrer Institute. The system was designed to record muon decays at rates up to 1 MHz and acquire data at rates up to 60 MB/sec. The system employed a parallel network of dual-processor machines and repeating acquisition cycles of deadtime-free time segments in order to reach the design goals. The system incorporated a versatile scheme for control and diagnostics and a custom web interface for monitoring experimental conditions., 19 pages, 8 figures, submitted to Nuclear Instruments and Methods A

The anomalous magnetic moment of the muon is one of the most precisely measured quantities in experimental particle physics. Its latest measurement at Brookhaven National Laboratory deviates from the Standard Model expectation by approximately 3.5 standard deviations. The goal of the new experiment, E989, now under construction at Fermilab, is a fourfold improvement in precision. Here, we discuss the details of the future measurement and its current status. C 2015 AIP Publishing LLC. [http://dx.doi.org/10.1063/1.4917553]

Background: The rate \lambda_pp\mu\ characterizes the formation of pp\mu\ molecules in collisions of muonic p\mu\ atoms with hydrogen. In measurements of the basic weak muon capture reaction on the proton to determine the pseudoscalar coupling g_P, capture occurs from both atomic and molecular states. Thus knowledge of \lambda_pp\mu\ is required for a correct interpretation of these experiments. Purpose: Recently the MuCap experiment has measured the capture rate \Lambda_S from the singlet p\mu\ atom, employing a low density active target to suppress pp\mu\ formation (PRL 110, 12504 (2013)). Nevertheless, given the unprecedented precision of this experiment, the existing experimental knowledge in \lambda_pp\mu\ had to be improved. Method: The MuCap experiment derived the weak capture rate from the muon disappearance rate in ultra-pure hydrogen. By doping the hydrogen with 20 ppm of argon, a competing process to pp\mu\ formation was introduced, which allowed the extraction of \lambda_pp\mu\ from the observed time distribution of decay electrons. Results: The pp\mu\ formation rate was measured as \lambda_pp\mu = (2.01 +- 0.06(stat) +- 0.03(sys)) 10^6 s^-1. This result updates the \lambda_pp\mu\ value used in the above mentioned MuCap publication. Conclusions: The 2.5x higher precision compared to earlier experiments and the fact that the measurement was performed at nearly identical conditions to the main data taking, reduces the uncertainty induced by \lambda_pp\mu\ to a minor contribution to the overall uncertainty of \Lambda_S and g_P, as determined in MuCap. Our final value for \lambda_pp\mu\ shifts \Lambda_S and g_P by less than one tenth of their respective uncertainties compared to our results published earlier., Comment: 12 pages, 6 figures, to be submitted to Phys. Rev. C