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Introduction: Peru has experienced one of the highest rates of COVID-19 with only 27% of the population vaccinated. College students must make decisions on vaccination based on their belief and knowledge about immunizations. The purpose of this study was to describe COVID-19 behaviors and beliefs toward immunization among college students in Lima, Peru. Methods: Undergraduate students from Universidad Maria Auxiliadora (UMA) participated in this descriptive study. The CDC National 2009 H1N1 Flu Survey was adapted to measure behaviors and beliefs about immunizations of COVID-19. Results: 818 students participated in the study during the 2020 academic year. Significant differences were identified about taking vaccine when it was available by age ( p = .02), gender ( p

The $\beta^-$ decay of $^{47}$K to $^{47}$Ca is an appropriate mechanism for benchmarking interactions spanning the $sd$ and $pf$ shells, but current knowledge of the $\beta^-$-decay scheme is limited. We have performed a high-resolution, high-efficiency study of the $\beta^-$-decay of $^{47}$K with the GRIFFIN spectrometer at TRIUMF-ISAC. The study revealed 48 new transitions, a more precise value for the $^{47}$K half-life (17.38(3)~s), and new spin and parity assignments for eight excited states. Levels placed for the first time here raise the highest state observed in $\beta^-$ decay to within 568(3) keV of the $Q$-value and confirm the previously measured large $\beta^-$-decay branching ratios to the low-lying states. Previously unobserved $\beta^-$-feeding to 3/2$^+$ states between 4.5 and 6.1~MeV excitation energy was identified with a total $\beta^-$-feeding intensity of 1.29(2)\%. The sum of the $B(GT)$ values for these states indicates that the $1s_{1/2}$ proton hole strength near this excitation energy is comparable to the previously known $1s_{1/2}$ proton and neutron hole strengths near 2.6 MeV.

Simpson and Tostevin proposed that the width and shape of exclusive parallel momentum distributions of the A

We report on high-statistics data from the $\beta^-$ decay of the $^{46}$K $J^{\pi}$ = 2$^-$ ground state taken with the GRIFFIN spectrometer located at the TRIUMF-ISAC facility. In total, 199 $\gamma$ rays and 42 excited states were placed in the level scheme, and from the observed $\beta$ feeding and angular correlations of pairs of cascading $\gamma$ rays, it was possible to assign spins and parities to excited states and determine mixing ratios for selected $\gamma$ rays. The level structure of $^{46}$Ca is compared to theoretical predictions from a microscopic valence-space Hamiltonian derived from two- (NN) and three-nucleon (3N) forces. These calculations are in reasonable agreement with the experimental data and indicate that the protons in this region are not as inert as would be expected for semi-magic nuclei.

We report on the observation of excited states in the neutron-deficient phosphorus isotopes $^{26,27,28}\mathrm{P}$ via in-beam $\ensuremath{\gamma}$-ray spectroscopy with both high-efficiency and high-resolution detector arrays. In $^{26}\mathrm{P}$, a previously unobserved level has been identified at 244(3) keV, two new measurements of the astrophysically important $3/{2}^{+}$ resonance in $^{27}\mathrm{P}$ have been performed, $\ensuremath{\gamma}$ decays have been assigned to the proton-unbound levels at 2216 and 2483 keV in $^{28}\mathrm{P}$, and the $\ensuremath{\gamma}$-ray line-shape method has been used to make the first determination of the lifetimes of the two lowest-lying excited states in $^{28}\mathrm{P}$. The expected Thomas-Ehrman shifts were calculated and applied to levels in the mirror nuclei. The resulting level energies from this procedure were then compared with the energies of known states in $^{26,27,28}\mathrm{P}$.

We used the 8$\pi$ $\gamma$-ray spectrometer at the TRIUMF-ISAC radiocative ion beam facility to obtain high-precision branching ratios for $^{19}$Ne $\beta^+$ decay to excited states in $^{19}$F. Together with other previous work, our measurements determine the superallowed $1/2^+ \to 1/2^+$ beta branch to the ground state in $^{19}$F to be 99.9878(7)\%, which is three times more precise than known previously. The implications of these measurements for testing a variety of weak interaction symmetries are discussed briefly.

An error was discovered in the extraction of the singles intensities in the original article. The corrections are reported in this erratum.

Malignant mesothelioma is a deadly disease with limited therapeutic options. EphB4 is an oncogenic tyrosine kinase receptor expressed in malignant mesothelioma as well as in a variety of cancers. It is involved in tumor microenvironment mediating angiogenesis and invasive cellular effects via both EphrinB2 ligand-dependent and independent mechanisms. The molecular network underlying EphB4 oncogenic effects is still unclear. Here we show that EphB4 expression in malignant mesothelioma cells is markedly decreased upon neutralization of cancer-secreted IGF-II. In particular, we demonstrate that EphB4 protein expression in malignant mesothelioma cells depend upon a degradation rescue mechanism controlled by the autocrine IGF-II-insulin receptor-A specific signaling axis. We show that the regulation of EphB4 expression is linked to a competing post-translational modification of its carboxy-terminal tail via phosphorylation of its tyrosine 987 by the Insulin receptor isoform-A kinase-associated activity in response to the autocrine IGF-II stimuli. Neutralization of this autocrine-induced EphB4-phosphorylation by IGF-II associates with the increased ubiquitination of EphB4 carboxy-terminal tail and with its rapid degradation. We also describe a novel Ubiquitin binding motif in the targeted region as part of the identified EphB4 phosphodegron and provide 3D modeling data supporting a possible model for the acute EphB4 PTM-driven regulation by IGF-II. Altogether, these findings disclose a novel molecular mechanism for the maintenance of EphB4-expression in malignant mesothelioma cells and other IGF-II-secreting cancers (IGF2omas).

Use of a beam-based approach is presented for establishing a rigidity calibration for the A1900 fragment separator located at the National Superconducting Cyclotron Laboratory. Also presented is why an alternative approach to the rigidity calibration – using detailed field maps of individual magnetic components – is not a feasible basis for deriving an accurate calibration. The level of accuracy achieved for the rigidity calibration is ±0.1%.

CITATION: Longfellow, B., et al. 2018. Measurement of key resonances for the 24Al( p,γ )25Si reaction rate using in-beam γ -ray spectroscopy. Physical Review C, 97(5):054307, doi:10.1103/PhysRevC.97.054307.

The electron-beam ion trap (EBIT) charge breeder of the ReA post-accelerator, located at the National Superconducting Cyclotron Laboratory (Michigan State University), started on-line operation in September 2015. Since then, the EBIT has delivered many pilot beams of stable isotopes and several rare-isotope beams. An operating aspect of the ReA EBIT is the breeding of high charge states to reach high reaccelerated beam energies. Efficiencies in single charge states of more than 20% were measured with ${^{39}\mathrm{K}}^{15+}$, ${^{85}\mathrm{Rb}}^{27+}$, ${^{47}\mathrm{K}}^{17+}$, and ${^{34}\mathrm{Ar}}^{15+}$. Producing high charge states demands long breeding times. This reduces the ejection frequency and, hence, increases the number of ions ejected per pulse. Another operating aspect is the ability to spread the distribution in time of the ejected ion pulses to lower the instantaneous rate delivered to experiments. Pulse widths were stretched from a natural $25\text{ }\text{ }\ensuremath{\mu}\mathrm{s}$ up to $\ensuremath{\sim}70\text{ }\text{ }\mathrm{ms}$. This publication reviews the progress of the ReA EBIT system over the years and presents the results of charge-breeding efficiency measurements and pulse-stretching tests obtained with stable- and rare-isotope beams. Studies performed with high sensitivity to identify and quantify stable-isotope contaminants from the EBIT are also presented, along with a novel method for purifying beams.

A Coulomb-excitation reorientation-effect measurement using the TIGRESS γ−ray spectrometer at the TRIUMF/ISAC II facility has permitted the determination of the 〈 2 1 + ‖ E 2 ˆ ‖ 2 1 + 〉 diagonal matrix element in 12C from particle−γ coincidence data and state-of-the-art no-core shell model calculations of the nuclear polarizability. The nuclear polarizability for the ground and first-excited (2 1 + ) states in 12C have been calculated using chiral NN N4LO500 and NN+3NF350 interactions, which show convergence and agreement with photo-absorption cross-section data. Predictions show a change in the nuclear polarizability with a substantial increase between the ground state and first excited 2 1 + state at 4.439 MeV. The polarizability of the 2 1 + state is introduced into the current and previous Coulomb-excitation reorientation-effect analyses of 12C. Spectroscopic quadrupole moments of Q S ( 2 1 + ) = + 0.053 ( 44 ) eb and Q S ( 2 1 + ) = + 0.08 ( 3 ) eb are determined, respectively, yielding a weighted average of Q S ( 2 1 + ) = + 0.071 ( 25 ) eb, in agreement with recent ab initio calculations. The present measurement confirms that the 2 1 + state of 12C is oblate and emphasizes the important role played by the nuclear polarizability in Coulomb-excitation studies of light nuclei.

The excited states of the proton emitter Lu151 were reinvestigated in a recoil-decay tagging experiment at the Accelerator Laboratory of the University of Jyvaskyla (JYFL). The level scheme built on the ground state of Lu151 was updated with five new γ-ray transitions. Large-scale shell model calculations were carried out in the model space consisting of the neutron and proton orbitals 0g7/2, 1d5/2, 1d3/2, 2s1/2, and 0h11/2 with the optimized monopole interaction in order to interpret the experimental level scheme of Lu151. It is found that the excitation energies of states above the 27/2- and 23/2+ isomeric levels in Lu151 can be sensitive to excitations from g7/2 and d5/2 to single-particle orbitals above N=Z=64.

A new method has been developed to detect and identify isomeric states produced in intermediate beam-energy reactions with secondary radioactive beams. Event-by-event identification of the reaction products allows for an unambiguous assignment of isomeric states to certain nuclei produced in fragmentation reactions. This versatile device allows for the identification of isomeric states with lifetimes between 100 ns and several ms. Combined prompt and delayed γ-ray spectroscopy give detailed information on the level schemes of exotic nuclei. This is particularly important in measurements of exclusive reaction cross-sections to several final states in the residue nucleus.

14C is an important consideration within safety assessments for proposed geological disposal facilities for radioactive wastes, since it is capable of re-entering the biosphere through the generation of 14C bearing gases. The irradiation of graphite moderators in the UK gas-cooled nuclear power stations has led to the generation of a significant volume of 14C-containing intermediate level wastes. Some of this 14C is present as a carbonaceous deposit on channel wall surfaces. Within this study, the potential of biofilm growth upon irradiated and 13C doped graphite at alkaline pH was investigated. Complex biofilms were established on both active and simulant samples. High throughput sequencing showed the biofilms to be dominated by Alcaligenes sp at pH 9.5 and Dietzia sp at pH 11.0. Surface characterisation revealed that the biofilms were limited to growth upon the graphite surface with no penetration of the deeper porosity. Biofilm formation resulted in the generation of a low porosity surface layer without the removal or modification of the surface deposits or the release of the associated 14C/13C. Our results indicated that biofilm formation upon irradiated graphite is likely to occur at the pH values studied, without any additional release of the associated 14C.

We report $B(E2;{0}_{1}^{+}\ensuremath{\rightarrow}{2}_{n}^{+})$ strengths for the neutron-rich $^{88,90}\mathrm{Kr}$ and $^{86}\mathrm{Se}$ isotopes from intermediate-energy Coulomb excitation. The electric quadrupole transition strengths to the first ${2}^{+}$ states complete, with considerably improved uncertainties, the evolution of quadrupole collectivity in the Kr and Se isotopes approaching $N=60$, for which $^{90}\mathrm{Kr}$ and $^{86}\mathrm{Se}$ had previously been the most uncertain. We also report significant excitation strength to several higher-lying ${2}^{+}$ states in the krypton isotopes. This fragmentation of $B(E2)$ strength in $^{88,90}\mathrm{Kr}$ confirms shell-model calculations in the $\ensuremath{\pi}(fpg)\text{\ensuremath{-}}\ensuremath{\nu}(sdgh)$ shell with an only minimally tuned shell-model setup that is based on a nucleon-nucleon interaction derived from effective field theory and effective charges adjusted to $^{86}\mathrm{Kr}$.

A new $\beta^{+}$ /EC branch of $0.11\pm 0.02$ % from the $(7)^{+}$ isomer of 124Cs was identified in a measurement of the decay of 124Cs using the $8\pi$ spectrometer at TRIUMF. Combinations of $\gamma$ - $\gamma$ , $\gamma$ - $e^{-}$ , and $e^{-}$ - $e^{-}$ coincidence data were used to further investigate the isomeric decay. Six new transitions were observed and their branching ratios were measured.

Author(s): Richard, AL; Crawford, HL; Fallon, P; Macchiavelli, AO; Bader, VM; Bazin, D; Bowry, M; Campbell, CM; Carpenter, MP; Clark, RM; Cromaz, M; Gade, A; Ideguchi, E; Iwasaki, H; Jones, MD; Langer, C; Lee, IY; Loelius, C; Lunderberg, E; Morse, C; Rissanen, J; Salathe, M; Smalley, D; Stroberg, SR; Weisshaar, D; Whitmore, K; Wiens, A; Williams, SJ; Wimmer, K; Yamamato, T | Abstract: The "island of inversion" at N≈20 for the neon, sodium, and magnesium isotopes has long been an area of interest both experimentally and theoretically due to the subtle competition between 0p-0h and np-nh configurations leading to deformed shapes. However, the presence of rotational band structures, which are fingerprints of deformed shapes, have only recently been observed in this region. In this work, we report on a measurement of the low-lying level structure of Mg33 populated by a two-stage projectile fragmentation reaction and studied with the Gamma Ray Energy Tracking In-Beam Nuclear Array (GRETINA). The experimental level energies, ground-state magnetic moment, intrinsic quadrupole moment, and γ-ray intensities show good agreement with the strong-coupling limit of a rotational model.

© 2016 Elsevier B.V. The γ-ray tracking array GRETINA was coupled to the S800 magnetic spectrometer for spectroscopy with fast beams of rare isotopes at the National Superconducting Cyclotron Laboratory on the campus of Michigan State University. We describe the technical details of this powerful setup and report on GRETINA's performance achieved with source and in-beam measurements. The γ-ray multiplicity encountered in experiments with fast beams is usually low, allowing for a simplified and efficient treatment of the data in the γ-ray analysis in terms of Doppler reconstruction and spectral quality. The results reported in this work were obtained from GRETINA consisting of 8 detector modules hosting four high-purity germanium crystals each. Currently, GRETINA consists of 10 detector modules.

The electromagnetic dipole strength in Be 11 between the bound states has been measured using low-energy projectile Coulomb excitation at bombarding energies of 1.73 and 2.09 MeV/nucleon on a Pt 196 target. An electric dipole transition probability B ( E 1 ; 1 / 2 − → 1 / 2 + ) = 0.102 ( 2 ) e 2 fm 2 was determined using the semi-classical code Gosia, and a value of 0.098 ( 4 ) e 2 fm 2 was determined using the Extended Continuum Discretized Coupled Channels method with the quantum mechanical code FRESCO. These extracted B ( E 1 ) values are consistent with the average value determined by a model-dependent analysis of intermediate energy Coulomb excitation measurements and are approximately 14 % lower than that determined by a lifetime measurement. The much-improved precisions of 2% and 4% in the measured B ( E 1 ) values between the bound states deduced using Gosia and the Extended Continuum Discretized Coupled Channels method, respectively, compared to the previous accuracy of ∼ 10 % will help in our understanding of and better improve the realistic inter-nucleon interactions.

In the UK, radioactive wastes currently planned for disposal in a geological disposal facility (GDF) include intermediate level waste, some low level waste and high level waste. Disposal of other materials, including spent fuel, uranium and plutonium is also being evaluated to inform the safety case for a GDF, if such materials were to be classified as wastes in the future. This paper describes the generic safety functions through which waste packages can contribute to the safety case of a GDF in the UK. It describes the engineering approach used or envisaged, in the UK and internationally, to ensure that waste packages retain their safety functions for the required periods of time and summarizes the scientific basis underpinning the current understanding of relevant evolution processes. Where gaps in the knowledge exist, the Nuclear Decommissioning Authority Radioactive Waste Management Directorate has identified specific research activities needed to close out such gaps to a level of maturity sufficient for this stage of the disposal programme (generic). This paper describes the latest results from their R&D programme and presents a summary of the research activities planned to meet the current needs of the disposal programme with specific reference to the topics of package evolution and criticality safety.

The current route in the UK for the conditioning and immobilization of most intermediate level waste for interim storage and geological disposal is to encapsulate in a cementitious matrix. However, certain waste materials, such as those containing reactive metals (e.g. uranium and aluminium), can corrode in the presence of the highly alkaline water in a cementitious environment. In their initial, undegraded form, polymeric materials can provide the appropriate, unreactive environment needed for the encapsulation of chemically active metals.This study examines the effects of gamma radiation on the stability of six candidate polymeric encapsulants, including a vinyl ester styrene resin (VES) and five epoxy resin formulations. The polymeric encapsulants were exposed to radiation doses up to 10 MGy using AMEC's cobalt-60 gamma irradiation facility and their radiation and chemical stability characterized by the use of a number of analytical techniques. These included flexural and compressive testing, Fourier transform infrared spectroscopy (FTIR), gel fraction, leach testing and gas evolution. The results show that the most stable resin in terms of radiation resistance and chemical stability was VES. Most of the epoxy resin materials also showed good generic stability, but the FTIR analysis showed the potential for dose-rate effects in one formulation.

Some of the illustrative concepts for the disposal of intermediate-level waste in a geological disposal facility in the UK employ a cementitious backfill around the waste packages. The concept for higher strength rocks would use a highly alkaline backfill composed of Portland cement (now known as CEM I), hydrated lime and limestone flour, referred to as Nirex reference vault backfill (NRVB).This paper reports a study of the extensive leaching of cured NRVB in a range of generic leachant compositions (deionized water, 0.1 M and 1 M NaCl solutions) under flow-through conditions using a flexible wall permeameter. The experiments were designed to run for up to two years and to pass at least 1000 volumes of leachant (defined as the cumulative leachate volume produced/NRVB solid specimen volume) through the NRVB samples. Results for the pH evolution profiles of the leachates and the microstructural analysis of the unleached and leached samples are presented.

The near field, together with the containment and isolation provided by the geosphere, contributes to the long-term safety provided by a geological disposal facility (GDF) after closure. The different engineered barriers can prevent or limit the release of radionuclides and their migration to the undisturbed host rock or geosphere and are expected to fulfil their post-closure safety functions for many thousands to hundreds of thousands of years. They will continue to contribute to containment after their eventual degradation when there would no longer be confidence that they would continue to fulfil all of their safety functions in their totality. By that time, significant radioactive decay will have occurred, substantially reducing the hazard associated with the wastes. Therefore, demonstration of long-term safety requires an understanding of the evolution of the engineered barriers and the consequences for the generic safety functions that the different barriers provide. This paper provides an overview of the research of the Nuclear Decommissioning Authority Radioactive Waste Management Directorate into the evolution of the near field of a GDF.

The release and migration of gaseous carbon-14 has been identified as a key issue for geological disposal of intermediate-level radioactive wastes in the UK. A significant fraction of carbon-14 in the UK inventory is in irradiated graphite. This paper describes measurements of gaseous carbon-14 releases from irradiated graphite on immersion in alkaline solution. Apparatus has been developed to discriminate organic and inorganic (14CO/14CO2) species in the gas phase by means of selective oxidation and capture. In the initial experiment, small amounts of gaseous carbon-14 (∼4 Bq) were released from 9 g of crushed graphite within a two-week period. In a long-term experiment, cumulative releases were measured periodically from an intact specimen of graphite over a 14 month period. A small fraction of the graphite carbon-14 inventory was released to the gas phase (∼0.004% as CO/CO2 and ∼0.001% associated with organic compounds). A larger quantity of carbon-14, about 0.1%, was released to the solution phase and was thought to be mainly 14CO2, with some possible organic component. In general, the rate of gaseous carbon-14 release decreased with time. The results suggest a small initial release of relatively labile, accessible carbon-14, with longer term release occurring at a much slower rate. Tritium (T) releases were also measured.

Gases will be generated in waste packages during their transport to a geological disposal facility (GDF), this generation will continue during GDF operations and after GDF closure. The range of gases produced will include flammable, radioactive and chemotoxic species. These must be managed to ensure safety during transport and operations, and the post-closure consequences need to be understood. The two primary post-closure gas issues for a GDF are the need for the system pressure to remain below a value at which irreversible damage to the engineered barrier system and host geology could occur, and the need to ensure that any flux of gas (in particular gaseous radionuclides) to the biosphere does not result in unacceptable risk. This paper provides an overview of the research of the Nuclear Decommissioning Authority, Radioactive Waste Management Directorate into gas generation and its migration from a GDF.

Polymerization-induced self-assembly (PISA) has become a widely used technique for the rational design of diblock copolymer nano-objects in concentrated aqueous solution. Depending on the specific PISA formulation, reversible addition–fragmentation chain transfer (RAFT) aqueous dispersion polymerization typically provides straightforward access to either spheres, worms, or vesicles. In contrast, RAFT aqueous emulsion polymerization formulations often lead to just kinetically-trapped spheres. This limitation is currently not understood, and only a few empirical exceptions have been reported in the literature. In the present work, the effect of monomer solubility on copolymer morphology is explored for an aqueous PISA formulation. Using 2-hydroxybutyl methacrylate (aqueous solubility = 20 g dm–3 at 70 °C) instead of benzyl methacrylate (0.40 g dm–3 at 70 °C) for the core-forming block allows access to an unusual “monkey nut” copolymer morphology over a relatively narrow range of target degrees of polymerization when using a poly(methacrylic acid) RAFT agent at pH 5. These new anisotropic nanoparticles have been characterized by transmission electron microscopy, dynamic light scattering, aqueous electrophoresis, shear-induced polarized light imaging (SIPLI), and small-angle X-ray scattering.

High precision measurements of the $ft$ values for superallowed Fermi $\beta$ transitions between $J^\pi~=~0^+$ isobaric analogue states allow for stringent tests of the electroweak interaction described by the Standard Model. These transitions provide an experimental probe of the Conserved-Vector-Current hypothesis, enable the most precise determination of the up-down ($V_{ud}$) element of the Cabibbo-Kobayashi-Maskawa quark-mixing matrix, and allow one to set stringent limits on the existence of scalar currents in the weak interaction. An extensive program of superallowed branching-ratio and half-life measurements at TRIUMF's Isotope Separator and Accelerator (ISAC) facility has covered the full range of superallowed emitters, from the lightest case, $^{10}$C, to the heaviest case for which precision data are currently available, $^{74}$Rb. These experiments have been performed using a 4$\pi$ continuous-flow gas proportional $\beta$ counter, the 8$\pi$ $\gamma$-ray spectrometer, and, most recently, the new high-efficiency GRIFFIN $\gamma$-ray spectrometer. In this paper, recent highlights from the superallowed Fermi $\beta$ decay program at TRIUMF will be summarized, including high-precision half-life measurements for all three of the lightest superallowed emitters, $^{10}$C, $^{14}$O, and $^{18}$Ne, with the greatest sensitivity to a potential weak scalar current contribution, as well as high-precision branching-ratio measurements for the heavy superallowed emitters $^{62}$Ga and $^{74}$Rb.

Twenty two patients over the age of 40 with stable spinal cord damage underwent overnight sleep studies to investigate the prevalence of sleep apnoea. Ten patients had some evidence of obstructive sleep apnoea (OSA). Hypoxic events were scored as number of dips of SaO2 more than 4% below the preceding 10 minute average (> 4% SaO2 dip rate). All the patients had more than five such dips per hour and six had clearly abnormal dip rates of more than 15 per hour. Two other patients had dip rates above 10 per hour without apnoeas but periods of central hypoventilation mainly during rapid eye movement (REM) sleep. OSA appears to be more common in older patients with spinal cord injury than in the general population. Possible relevant factors include patient selection, reduced ventilatory function secondary to spinal cord damage, sleep posture and medication.

There is significant evidence supporting the existence of deformed ground states within the neutron-rich N≈20 neon, sodium, and magnesium isotopes that make up what is commonly called the "island of inversion." However, the rotational band structures, which are a characteristic fingerprint of a rigid nonspherical shape, have yet to be observed. In this work, we report on a measurement and analysis of the yrast (lowest lying) rotational band in Mg32 up to spin I=6+ produced in a two-step projectile fragmentation reaction and observed using the state-of-the-art γ-ray tracking detector array, GRETINA (γ-ray energy tracking in-beam nuclear array). Large-scale shell-model calculations using the SDPF-U-MIX effective interaction show excellent agreement with the new data. Moreover, a theoretical analysis of the spectrum of rotational states as a function of the pairing gap, together with cranked-shell-model calculations, provides intriguing evidence for a reduction in pairing correlations with increased angular momentum, also in line with the shell-model results, This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under Contracts No. DE-AC02-05CH11231 (LBNL) and No. DE-AC02-06CH11357 (ANL), by the Department of Energy National Nuclear Security Administration under Award No. DE-NA0000979 and the National Science Foundation (NSF) under PHY-1102511. GRETINA was funded by the U.S. DOE Office of Science. Operation of the array at NSCL is supported by NSF under Cooperative Agreement PHY11-02511 (NSCL) and DOE under Grant No. DE-AC02- 05CH11231 (LBNL). A.P. is partly supported by MINECO (Spain) Grant FPA2014-57196 and Programme “Centros de Excelencia Severo Ochoa” SEV-2012-0249

The present work has used microwave plasma chemical vapour deposition to generate suitable isotopically labelled carbonaceous deposits on the surface of Pile Grade A graphite for use as surrogates for studying the behaviour of the deposits observed on irradiated graphite extracted from UK Magnox reactors. These deposits have been shown elsewhere to contain an enhanced concentration of 14C compared to the bulk graphite. A combination of Raman spectroscopy, ion beam milling with scanning electron microscopy and secondary ion mass spectrometry were used to determine topography and internal morphology in the formed deposits. Direct comparison was made against deposits found on irradiated graphite samples trepanned from a Magnox reactor core and showed a good similarity in appearance. This work suggests that the microwave plasma chemical vapour deposition technique is of value in producing simulant carbon deposits, being of sufficiently representative morphology for use in non-radioactive surrogate studies of post-disposal behaviour of 14C-containing deposits on some irradiated Magnox reactor graphite.

Masses of 238U projectile fragments have been measured with time-resolved Schottky Mass Spectrometry (SMS) at the FRS-ESR facility at GSI. The exotic nuclei were created in the production target at the entrance of the fragment separator FRS, spatially separated in flight and injected into the storage-cooler ring ESR at about 70% light velocity. This means the ions were mainly bare or carried only a few electrons, e.g., the population of Li-like ions was below 1% for Pt fragments. Accurate newmass values of 33 neutron-rich, stored exotic nuclei in the element range from platinum to uranium have been obtained for the first time. In total more than 150 nuclides including references with well-known masses have been covered in this large-area SMS measurement. A novel data analysis has been applied which reduces the systematic errors by taking into account the velocity profile of the cooler electrons and the residual ion-optical dispersion in this part of the storage ring. The experiment, the data analysis, and the mass values are presented. The experimental data are compared with theoretical predictions demonstrating systematic deviations of up to 1500 keV from modern mass models.

Analysis of the average number of applicants received from schools that engaged in the Bristol ChemLabS Outreach program prior to a student‟s application with those that did not engage, shows a significant increase in applicants from engaged schools. The significance is weaker when just Post 16 students are considered but this is almost certainly due to a smaller sample size. When this analysis was inspected in terms of the distance of the school from the University of Bristol, there was an increase in the number of applicants from engaged schools irrespective of distance. However, a statistically significant increase was observed for schools within 50 miles of the University from an analysis of just Post 16 students. Students who applied to the department from an engaged school were more likely to accept an offer and also to make the department their firm acceptance. A slightly higher number of applications that were rejected came from engaged schools too. There are two possible reasons; first, the engagement may have encouraged more students who did not have the required entry qualifications. Second, during the period of analysis, the overall entry grades went up by one grade each year. Such a dramatic rise was probably the reason for the slightly elevated numbers.

Over many decades, the creep and creep fracture properties of metals and alloys have commonly been described using power law relationships. However, with this approach, controversies still surround the mechanisms proposed to account for the stress and temperature dependencies of the minimum creep rate and rupture life. Similarly, power law and related expressions do not allow extrapolation of short term data sets to predict the long term properties required for engineering design purposes. For these reasons, over the last 25 years, three UK approaches have evolved, termed the θ projection concept, the hyperbolic tangent method and the Wilshire equations. These methodologies are now applied to results for the aluminium alloy Al 2124, recommending reappraisal of current reliance on power law expressions for theoretical and practical purposes.

238U projectile fragments have been created at the entrance of the fragment separator FRS, spatially separated in flight within 0.45 μs and injected into the storage-cooler ring ESR at 7.9 Tm corresponding to about 70% light velocity. Accurate new mass values and lifetime information of the stored exotic nuclei in the element range from platinum to uranium have been obtained with single-particle Schottky spectrometry. In this experiment the new isotopes of 236Ac, 224At, 221Po, 222Po, and 213Tl were discovered. The isotopes were unambiguously identified and their masses measured. In addition, the time-correlated data have provided information on the lifetime of the new nuclides. The discovery of isotopes along with accurate mass measurement has been achieved for the first time at the FRS-ESR facility. The results will contribute to the knowledge of the decay products from the r-process nuclei and enable a crucial test of the predictive power of modern nuclear mass and half-life models.

The wave-function composition for the low-lying states in 29 Na was explored by measuring their electromagnetic properties using the Coulomb-excitation technique. A beam of 29 Na ions, postaccelerated to 70 MeV, bombarded a 110 Pd target with a rate of up to 600 particles per second at the recently commissioned ISAC-II facility at TRIUMF. Six segmented HPGe clover detectors of the TIGRESS γ -ray spectrometer were used to detect deexcitation γ rays in coincidence with scattered or recoiling charged particles in the segmented silicon detector, BAMBINO. The reduced transition matrix element | 〈 5 2 1 + | | E 2 | | 3 2 gs + 〉 | in 29 Na was derived to be 0.237(21) e b from the measured γ -ray yields for both projectile and target. This first-time measured value is consistent with the most recent Monte Carlo shell-model calculation, indicating a significant admixture of both sd and pf components in the wave function, and also providing evidence for the narrowing of the neutron s d – p f shell gap from ∼ 6 MeV for stable nuclei to ∼ 3 MeV for 29 Na.

I present results from an optical spectroscopic investigation of the binary system HD 42401 (V1388 Ori; B2.5 IV-V + B3 V). A combined analysis of V-band photometry and radial velocities indicates that the system has an orbital period of 2.18706 +/- 0.00005 days and an inclination of 75.5 +/- 0.2 degrees. This solution yields masses and radii of M1 = 7.42 +/- 0.08 Solar Masses and R1 = 5.60 +/- 0.04 Solar Radii for the primary and M2 = 5.16 +/- 0.03 Solar Masses and R2 = 3.76 +/- 0.03 Solar Radii for the secondary. Based on the position of the two stars plotted on a theoretical H-R diagram, I find that the age of the system is > 25 Myr and that both stars appear overluminous for their masses compared to single star evolutionary tracks. A fit of the spectral energy distribution based on photometry from the literature yields a distance to HD 42401 of 832 +/- 89 parsecs., 20 pages, 8 figures, Added and modified figures and text. Accepted to AJ

A BSTRACT.— Reef fish movements over short and long time frames have important consequences for identifying essential fish habitat, quantifying ecological flows across the seascape and designing marine reserves. We use grunts (Haemulidae) as a representative model group for quantifying movement in terms of distances, time scales, temporal patterns, habitat associations and controls. Here, we provide a review based on recent studies and our own experience. The ritualized, twilight feeding migrations of grunts represent an important mechanism for transferring nutrients and organic matter across habitat boundaries, with movements on the order of 100-300 m. Both compass orientation and vision are used for navigation during feeding migrations. Feeding movements of adults are less ritualized in both space and time and typically occur on the same scale of distance as juveniles, although longer excursions have been documented. Ontogenetic migrations occur over years and take the form of discrete habitat shifts, with most individuals moving progressively offshore. Distances and pathways followed by fish will depend on the exact width of the shelf and distribution of suitable habitats. Transplant experiments suggest there are significant barriers to fish migration, and migration corridors, especially reef margins, seem to be important in determining the direction of ontogenetic habitat shifts, but these may be disrupted by environmental perturbations. Theoretical considerations relative to barrier perception and growth-survival trade-offs appear to explain normal movements of grunts and their responses to environmental perturbations, but lack of information on how fish may sense new locations at distance prevents the full use of theory to generate rules of migration covering timing, distance and direction.

A new focal plane detector arrangement for the Fragment Mass Analyzer (FMA) has been built and tested at Argonne National Laboratory. This set-up is particularly sensitive for performing Recoil-Isomer Tagging on nuclei with isomeric states with lifetimes in the microsecond range. Recoiling nuclei from fusion–evaporation reactions at the target position are dispersed by their ratio of mass to charge ( A / q ) by the FMA and stopped in low pressure gas (air) at the focal plane. Subsequent gamma decays from isomeric states in the reaction products are observed using Ge detectors. A constant gas flow through the focal plane chamber efficiently removes longer-lived beta-decaying species from sight of the detectors. This set-up has been commissioned successfully with the microsecond isomer in 80Rb, populated via the 52Cr(32S, 3pn) reaction at 135 MeV.

BACKGROUND AND STUDY AIMS: Inadvertent injection of contrast agent into the pancreatic duct is believed to be an important contributor to pancreatitis occurring after endoscopic retrograde cholangiopancreatography (post-ERCP pancreatitis, PEP). Our aim was to examine whether primary deep biliary cannulation with a guide wire is associated with a lower rate of PEP than conventional contrast-assisted cannulation. PATIENTS AND METHODS: From August 2003 to April 2006 all patients with an intact papilla who were referred for ERCP were eligible. Patients with pancreatic or ampullary cancer were excluded. Patients were randomized to undergo sphincterotome biliary cannulation using either contrast injection or a guide wire. The ERCP fellow attempted initially for 5 min. If unsuccessful, the consultant attempted for 5 min using the same technique, followed by crossover to the other technique in the same sequence and then needle-knife sphincterotomy where appropriate. Patients were assessed clinically after the procedure, then followed up with telephone interviews after 24 hours and 30 days, and serum amylase and lipase tests after 24 hours. RESULTS: Out of 1654 patients undergoing ERCP, 413 were included in the study. PEP occurred in 29 / 413 (7.0 %): 16 in the guide-wire arm, 13 in the contrast arm (p = 0.48). The overall cannulation success rate was 97.3 %. Cannulation was successful without crossover in 323 / 413 patients (78.2 %): 167 / 202 (81.4 %) in the guide-wire arm and 156 / 211 (73.9 %) in the contrast arm (p = 0.03). Multivariate analysis demonstrated female sex (OR = 2.7, p = 0.04), suspected sphincter of Oddi dysfunction (OR = 5.5, p = 0.01), and complete filling of the pancreatic duct with contrast agent (OR = 3.5, p = 0.02) to be independently associated with PEP. The risk of PEP increased incrementally with each attempt at the papilla (OR 1.4 per attempt, p = 0.04) to greater than 10 % after four or more attempts. CONCLUSIONS: The guide-wire technique improves the primary success rate for biliary cannulation during ERCP but does not reduce the incidence of PEP compared to the conventional contrast technique. The incidence of PEP increases incrementally with each attempt at the papilla.

A general technique that corrects γ -ray gated β decay-curve data for detector pulse pile-up is presented. The method includes corrections for non-zero time-resolution and energy-threshold effects in addition to a special treatment of saturating events due to cosmic rays. This technique is verified through a Monte Carlo simulation and experimental data using radioactive beams of Na 26 implanted at the center of the 8 π γ -ray spectrometer at the ISAC facility at TRIUMF in Vancouver, Canada. The β -decay half-life of Na 26 obtained from counting 1809-keV γ -ray photopeaks emitted by the daughter Mg 26 was determined to be T 1 / 2 = 1.07167 ± 0.00055 s following a 27 σ correction for detector pulse pile-up. This result is in excellent agreement with the result of a previous measurement that employed direct β counting and demonstrates the feasibility of high-precision β -decay half-life measurements through the use of high-purity germanium γ -ray detectors. The technique presented here, while motivated by superallowed-Fermi β decay studies, is general and can be used for all half-life determinations (e.g. α -, β -, X-ray, fission) in which a γ -ray photopeak is used to select the decays of a particular isotope.

The isotope separator and accelerator (ISAC) facility located at the TRIUMF laboratory in Vancouver, Canada, is one of the world’s most advanced isotope separator on-line-type radioactive ion beam facilities. An extensive γ-ray spectroscopy programme at ISAC is centred around two major research facilities: (i) the 8π γ-ray spectrometer for β-delayed γ-ray spectroscopy experiments with the low-energy beams from ISAC-I, and (ii) the next generation TRIUMF-ISAC gamma-ray escape suppressed spectrometer (TIGRESS) for in-beam experiments with the accelerated radioactive-ion beams. An overview of these facilities and recent results from the diverse programme of nuclear structure and fundamental interaction studies they support is presented.

Placental insufficiency, resulting in restriction of fetal substrate supply, is a major cause of intrauterine growth restriction (IUGR) and increased neonatal morbidity. Fetal adaptations to placental restriction maintain the growth of key organs, including the heart, but the impact of these adaptations on individual cardiomyocytes is unknown. Placental and hence fetal growth restriction was induced in fetal sheep by removing the majority of caruncles in the ewe before mating (placental restriction, PR). Vascular surgery was performed on 13 control and 11 PR fetuses at 110–125 days of gestation (term: 150 ± 3 days). PR fetuses with a mean gestational Po2 < 17 mmHg were defined as hypoxic. At postmortem (135 days), fetal hearts were collected, and cardiomyocytes were isolated and fixed. Proliferating cardiomyocytes were counted by immunohistochemistry of Ki67 protein. Cardiomyocytes were stained with methylene blue to visualize the nuclei, and the proportion of mononucleated cells and length and width of cardiomyocytes were measured. PR resulted in chronic fetal hypoxia, IUGR, and elevated plasma cortisol concentrations. Although there was no difference in relative heart weights between control and PR fetuses, there was an increase in the proportion of mononucleated cardiomyocytes in PR fetuses. Whereas mononucleated and binucleated cardiomyocytes were smaller, the relative size of cardiomyocytes when expressed relative to heart weight was larger in PR compared with control fetuses. The increase in the relative proportion of mononucleated cardiomyocytes and the relative sparing of the growth of individual cardiomyocytes in the growth-restricted fetus are adaptations that may have long-term consequences for heart development in postnatal life.