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The β-delayed one- and two-neutron emission probabilities (P_{1n} and P_{2n}) of 20 neutron-rich nuclei with N≥82 have been measured at the RIBF facility of the RIKEN Nishina Center. P_{1n} of ^{130,131}Ag, ^{133,134}Cd, ^{135,136}In, and ^{138,139}Sn were determined for the first time, and stringent upper limits were placed on P_{2n} for nearly all cases. β-delayed two-neutron emission (β2n) was unambiguously identified in ^{133}Cd and ^{135,136}In, and their P_{2n} were measured. Weak β2n was also detected from ^{137,138}Sn. Our results highlight the effect of the N=82 and Z=50 shell closures on β-delayed neutron emission probability and provide stringent benchmarks for newly developed macroscopic-microscopic and self-consistent global models with the inclusion of a statistical treatment of neutron and γ emission. The impact of our measurements on r-process nucleosynthesis was studied in a neutron star merger scenario. Our P_{1n} and P_{2n} have a direct impact on the odd-even staggering of the final abundance, improving the agreement between calculated and observed Solar System abundances. The odd isotope fraction of Ba in r-process-enhanced (r-II) stars is also better reproduced using our new data.

Experimental determination of the cross sections of proton capture on radioactive nuclei is extremely difficult. Therefore, it is of substantial interest for the understanding of the production of the p-nuclei. For the first time, a direct measurement of proton-capture cross sections on stored, radioactive ions became possible in an energy range of interest for nuclear astrophysics. The experiment was performed at the Experimental Storage Ring (ESR) at GSI by making use of a sensitive method to measure (p,γ) and (p,n) reactions in inverse kinematics. These reaction channels are of high relevance for the nucleosyn-thesis processes in supernovae, which are among the most violent explosions in the universe and are not yet well understood. The cross section of the 118Te(p,γ) reaction has been measured at energies of 6 MeV/u and 7 MeV/u. The heavy ions interacted with a hydrogen gas jet target. The radiative recombination process of the fully stripped 118Te ions and electrons from the hydrogen target was used as a luminosity monitor. An overview of the experimental method and preliminary results from the ongoing analysis will be presented.

Neutron-induced reaction cross sections of unstable nuclei are essential for understanding the synthesis of heavy elements in stars and for applications in nuclear technology. However, their measurement is very complicated due to the radioactivity of the targets involved. We propose to circumvent this problem by using the surrogate reaction method in inverse kinematics, where the nucleus formed in the neutron- induced reaction of interest is produced by a reaction involving a radioactive heavy-ion beam and a stable, light target nucleus. The probabilities as a function of the compound-nucleus excitation energy for γ-ray emission, neutron emission and fission, which can be measured with the surrogate reaction, are particularly useful to constrain model parameters and to obtain more accurate predictions of the neutron-induced reaction cross sections of interest. Yet, the full development of the surrogate method is hampered by numerous long- standing target issues, which can be solved by combining surrogate reactions with the unique and largely unexplored possibilities at heavy-ion storage rings. In this contribution, we describe the developments we are carrying out to measure for the first time simultaneously γ-ray emission, neutron emission and fission probabilities at the storage rings of the GSI/FAIR facility. In particular, we will present the first results of the proof of principle experiment, which we performed in June 2022 at the Experimental Storage Ring (ESR) of GSI/FAIR.

At the RIKEN Nishina Center, exotic neutron-rich isotopes of Ba, La, Ce, Pr, and Nd were measured. This work reports their half-lives (T1/2) and β-delayed neutron-emission probabilities (Pxn). The setup consisted of the BigRIPS in-flight separator for particle identification, the Advanced Implantation Detector Array (AIDA) for ions and β detection, and the BRIKEN neutron counter for neutron detection. Using this arrangement, 4 new T1/2 and 14 new P1n were measured. Furthermore, 38 T1/2 and 2 P1n values were remeasured, decreasing the uncertainties for some of them. In addition to improving predictions of nucleosynthesis models that describe the production of the rare-earth peak at A ∼ 160 via the r-process, these additional experimental data should help to constrain theoretical models for calculations of T1/2 and Pxn in this region.

The β-delayed neutron-emission probabilities of 28 exotic neutron-rich isotopes of Pm, Sm, Eu, and Gd were measured for the first time at RIKEN Nishina Center using the Advanced Implantation Detector Array (AIDA) and the BRIKEN neutron detector array. The existing β-decay half-life (T 1/2) database was significantly increased toward more neutron-rich isotopes, and uncertainties for previously measured values were decreased. The new data not only constrain the theoretical predictions of half-lives and β-delayed neutron-emission probabilities, but also allow for probing the mechanisms of formation of the high-mass wing of the rare-earth peak located at A ≈ 160 in the r-process abundance distribution through astrophysical reaction network calculations. An uncertainty quantification of the calculated abundance patterns with the new data shows a reduction of the uncertainty in the rare-earth peak region. The newly introduced variance-based sensitivity analysis method offers valuable insight into the influence of important nuclear physics inputs on the calculated abundance patterns. The analysis has identified the half-lives of 168Sm and of several gadolinium isotopes as some of the key variables among the current experimental data to understand the remaining abundance uncertainty at A = 167–172.

This experiment was performed at RI Beam Factory operated by RIKEN Nishina Center and CNS, University of Tokyo. O.H, T.D, P.J.W, C.G.B, C.J.G and D.K would like to thank STFC, UK for support. This research was sponsored in part by the Office of Nuclear Physics, U.S. Department of Energy under Award No. DE-FG02-96ER40983 (UTK) and DEAC05-00OR22725 (ORNL), and by the National Nuclear Security Administration under the Stewardship Science Academic Alliances program through DOE Award No. DENA0002132. This work was supported by National Science Foundation under Grants No. PHY-1430152 (JINA Center for the Evolution of the Elements), No. PHY-1565546 (NSCL), and No. PHY-1714153 (Central Michigan University). This work was supported by the Polish National Science Center under Contracts No. UMO-2015/18/E/ST2/00217, No. 2017/01/X/ST2/01144, No. 2019/33/N/ST2/03023 and No. 2020/36/T/ST2/00547. This work was also supported by JSPS KAKENHI (Grants No. 14F04808, No. 17H06090, No. 25247045, and No. 19340074). This work was also supported by Spanish Ministerio de Economia y Competitividad grants (FPA2011-06419, FPA2011-28770-C03-03, FPA2014-52823-C2-1-P, FPA2014-52823-C2-2-P, SEV-2014-0398, IJCI-2014-19172), by European Commission FP7/EURATOM Contract No. 605203, by the UK Science and Technology Facilities Council Grant No. ST/N00244X/1, by the National Research Foundation (NRF) in South Korea (No. 2016K1A3A7A09005575, No. 2015H1A2A1030275) and by the Natural Sciences and Engineering Research Council of Canada (NSERC) via the Discovery Grants SAPIN-2014-00028 and RGPAS 462257-2014. TRIUMF receives federal funding via a contribution agreement with the National Research Council Canada. This work was also supported by NKFIH (NN128072), and by the UNKP-20-5-DE-2 New National Excellence Program of the Ministry of Human Capacities of Hungary. G.G.K. acknowledges support from the Janos Bolyai research fellowship of the Hungarian Academy of Sciences. M.W.-C. acknowledges support from the Polish NCN project Miniatura No. 2017/01/X/ST2/01144. Z.L was supported by the National Key Research and Development Program of China (Contract No. 2018YFA0404402), the National Natural Science Foundation of China (Grants No. 11961141004, No. 11735017, No. 11675225 and No. 11635003) and the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDB34000000). M.R.M. performed this work under the auspice of the U.S. Department of Energy at Los Alamos National Laboratory. Los Alamos National Laboratory is operated by Triad National Security, LLC, for the National Nuclear Security Administration of U.S. Department of Energy (Contract No. 89233218CNA000001).

A high-precision branching ratio measurement for the superallowed Fermi $\beta^{+}$ emitter $^{62}$Ga was performed with the Gamma-Ray Infrastructure for Fundamental Investigations of Nuclei (GRIFFIN) spectrometer at the Isotope Separator and Accelerator (ISAC) radioactive ion beam facility at TRIUMF. The high efficiency of the GRIFFIN spectrometer allowed 63 $\gamma$-ray transitions, with intensities down to $\approx$1 part per million (ppm) per $^{62}$Ga $\beta^{+}$ decay, to be placed in the level scheme of the daughter nucleus $^{62}$Zn, establishing the superallowed $\beta$ branching ratio for $^{62}$Ga decay to be 99.8577$^{+0.0023}_{-0.0029}\%$, a factor of 4 more precise than the previous world average. For several cascades, $\gamma-\gamma$ angular correlation measurements were performed to assign spins and/or determine the mixing ratios of transitions. In particular, the spin of the 2.342 MeV excited state in the daughter nucleus $^{62}$Zn was definitively assigned as $J = 0$. This assignment resolves a discrepancy between previous measurements and has important implications for the isospin symmetry breaking correction, $\delta_{C1}$, in $^{62}$Ga superallowed Fermi $\beta$ decay.

In-flight fission of a 345 MeV per nucleon 238U primary beam on a 2 mm thick 9Be target has been used to produce and study the decays of a range of neutron-rich nuclei centred around the doubly mid-shell nucleus 170Dy at the RIBF Facility, RIKEN, Japan. The produced secondary fragments of interest were identified eventby- event using the BigRIPS separator. The fragments were implanted into the WAS3ABI position sensitive silicon active stopper which allowed pixelated correlations between implants and their subsequent β-decay. Discrete γ-ray transitions emitted following decays from either metastable states or excited states populated following beta decay were identified using the 84 coaxial high-purity germanium (HPGe) detectors of the EURICA spectrometer, which was complemented by 18 additional cerium-doped lanthanum bromide (LaBr3)

Physics letters / B 762, 404 - 408 (2016). doi:10.1016/j.physletb.2016.09.058, Published by North-Holland Publ., Amsterdam

Aquesta es una copia de la versio author’s final draft d'un article publicat a la revista [Physical Review C ]. URL d'aquest document a UPCommons E-prints: http://hdl.handle.net/2117/174873

Isomeric states in 59,61Ti have been populated in the projectile fragmentation of a 345 AMeV 238U beam at the Radioactive Isotope Beam Factory. The decay lifetimes and delayed gamma-ray transitions were measured with the EURICA array. Besides the known isomeric state in 59Ti, two isomeric states in 61Ti are observed for the first time. Based on the measured lifetimes, transition multipolarities as well as tentative spins and parities are assigned. Large-scale shell model calculations based on the modified LNPS interaction show that both 59Ti and 61Ti belong to the Island of Inversion at N=40 with ground state configurations dominated by particle-hole excitations to the g_9/2 and d_5/2 orbits., Phys. Lett. B accepted

© 2019, Springer Nature Switzerland AG. We made an experiment to measure half-lives T1/2 and neutron emission probabilities Pxn of nuclei around mass 80, aiming to improve r-process abundance calculations around the first abundance peak with a new dedicated experimental setup at RIKEN. Details of the experiment and a few preliminary results are presented.

The neutron-rich dysprosium isotopes ¹⁶⁸Dy₁₀₂ and ¹⁶⁹Dy₁₀₃ have been investigated using the EURICA γ-ray spectrometer, following production via in-flight fission of a high-intensity uranium beam in conjunction with isotope separation through the BigRIPS separator at RIBF in RIKEN Nishina Center. For ¹⁶⁸Dy, a previously unreported isomer with a half-life of 0.57(7) μs has been identified at an excitation energy of 1378 keV, and its presence affirmed independently using γ-γ-γ coincidence data taken with Gammasphere via two-proton transfer from an enriched ¹⁷⁰Er target performed at Argonne National Laboratory. This isomer is assigned Jπ = Kπ = (4⁻) based on the measured transition strengths, decay patterns, and the energy systematics for two-quasiparticle states in N = 102 isotones. The underlying mechanism of two-quasiparticle excitations in the doubly midshell region is discussed in comparison with the deformed QRPA and multi-quasiparticle calculations. In ¹⁶⁹Dy, the B(E2) value for the transition de-exciting the previously unreported Kπ = (1/2⁻) isomeric state at 166 keV to the Kπ = (5/2⁻) ground state is approximately two orders of magnitude larger than the E2 strength for the corresponding isomeric-decay transition in the N = 103 isotone ¹⁷³Yb, suggesting the presence of a significant γ-vibrational admixture with a dominant neutron one-quasiparticle component in the isomeric state.

Many choices are available in order to evaluate large radioactive decay networks. %multi-particle decay data. There are many parameters that influence the calculated $\beta$-decay delayed single and multi-neutron emission branching fractions. We describe assumptions about the decay model, background, and other parameters and their influence on $\beta$-decay delayed multi-neutron emission analysis. An analysis technique, the ORNL BRIKEN analysis procedure, for determining $\beta$-delayed multi-neutron branching ratios in $\beta$-neutron precursors produced by means of heavy-ion fragmentation is presented. The technique is based on estimating the initial activities of zero, one, and two neutrons occurring in coincidence with an ion-implant and $\beta$ trigger. The technique allows one to extract $\beta$-delayed multi-neutron decay branching ratios measured with the hybrid \textsuperscript{3}He BRIKEN neutron counter. As an example, two analyses of the $\beta$-neutron emitter \textsuperscript{77}Cu based on different {\it a priori} assumptions are presented along with comparisons to literature values., Comment: 21 pages, 10 figures

A new detection system has been installed at the RIKEN Nishina Center (Japan) to investigate decay properties of very neutron-rich nuclei. The setup consists of three main parts: a moderated neutron counter , a detection system sensitive to the implantation and decay of radioactive ions, and γ -ray detectors. We describe here the setup, the commissioning experiment and some selected results demonstrating its performance for the measurement of half-lives and β -delayed neutron emission probabilities. The methodology followed in the analysis of the data is described in detail. Particular emphasis is placed on the correction of the accidental neutron background.

This contribution will report on the experimental work on the level structure of 168Dy. The experimental data have been taken as part of the EURICA decay spectroscopy campaign at RIBF, RIKEN in November 2014. In the experiment, a 238U primary beam is accelerated up to 345 MeV/u with an average intensity of 12 pnA. The nuclei of interest are produced by in-flight fission of 238U impinging on Be target with a thickness of 5 mm. The excited states of 168Dy have been populated through the decay from a newly identified isomeric state and via the β decay from 168Tb. In this contribution, scientific motivations, experimental procedure and some preliminary results for this study are presented.

One of the most successful descriptions of the structure of atomic nuclei is the spherical shell model. It, however, becomes impractical when moving away from closed-shell nuclei. Instead, it is the interplay between the macroscopic shape degrees of freedom and the microscopic nature of the underlying single-particle structure in a deformed basis that determines the nuclear structure. Being the heaviest nucleus precisely in the middle of, known, closed proton and neutron shells, $^{170}$Dy has become a central calibration point for tests of collective models of nuclear physics. However, besides one candidate transition from a previous experiment in Legnaro, Italy, no experimental information is available for this nucleus. Using the EURICA setup at RIKEN, which couples the worlds highest intensity in-flight fission facility with a high-efficiency HPGe array, an experiment in November 2014 produced $^{170}$Dy nuclei by in-flight fission of a $^{238}$U beam. The results from this experiment provide a wealth of information on this elusive nucleus, including the evolution of quadrupole collectivity, rigidity and higher order deformations, as well as the long sought for isomeric $K=6^+$ state, predicted to be exceptionally pure at mid-shell. These results provide us with a rich level scheme for discussing both single-particle and collective structures at mid-shell.

The conceptual design of the BRIKEN neutron detector at the radioactive ion beam factory (RIBF) of the RIKEN Nishina Center is reported. The BRIKEN setup is a complex system aimed at detecting heavy-ion implants, ß particles, ¿ rays and ß-delayed neutrons. The whole setup includes the Advanced Implantation Detection Array (AIDA), two HPGe Clover detectors and up to 166 3He-filled counters embedded in a high-density polyethylene moderator. The design is quite complex due to the large number and different types of 3He-tubes involved and the additional constraints introduced by the ancillary detectors for charged particles and ¿ rays. This article reports on a novel methodology developed for the conceptual design and optimisation of the 3He-counter array, aiming for the best possible performance in terms of neutron detection. The algorithm is based on a geometric representation of two selected detector parameters of merit, namely, the average neutron detection efficiency and the efficiency flatness as a function of a reduced number of geometric variables. The response of the neutron detector is obtained from a systematic Monte Carlo simulation implemented in GEANT4. The robustness of the algorithm allowed us to design a versatile detection system, which operated in hybrid mode includes the full neutron counter and two clover detectors for high-precision gamma spectroscopy. In addition, the system can be reconfigured into a compact mode by removing the clover detectors and re-arranging the 3He tubes in order to maximize the neutron detection performance. Both operation modes shows a rather flat and high average efficiency. In summary, we have designed a system which shows an average efficiency for hybrid mode (3He tubes + clovers) of 68.6% and 64% for neutron energies up to 1 and 5 MeV, respectively. For compact mode (only 3He tubes), the average efficiency is 75.7% and 71% for neutron energies up to 1 and 5 MeV, respectively. The performance of the BRIKEN detection system has been also quantified by means of Monte Carlo simulations with different neutron energy distributions.

© The Authors, published by EDP Sciences, 2017. This short paper presents the identification of a metastable, isomeric-state decay in the neutron-rich odd-odd, prolate-deformed nucleus 166Tb. The nucleus of interest was formed using the in-flight fission of a 345 MeV per nucleon 238U primary beam at the RIBF facility, RIKEN, Japan. Gamma-ray transitions decaying from the observed isomeric states in 166Tb were identified using the EURICA gamma-ray spectrometer, positioned at the final focus of the BigRIPS fragments separator. The current work identifies a single discrete gamma-ray transition of energy 119 keV which de-excites an isomeric state in 166Tb with a measured half-life of 3.5(4) μs. The multipolarity assignment for this transition is an electric dipole and is made on the basis internal conversion and decay lifetime arguments. Possible two quasi-particle Nilsson configurations for the initial and final states which are linked by this transition in 166Tb are made on the basis of comparison with Blocked BCS Nilsson calculations, with the predicted ground state configuration for this nucleus arising from the coupling of the v(1-/2)[521] and π(3+/2) Nilsson orbitals. ispartof: EPJ Web of Conferences vol:146 ispartof: ND 2016: International Conference on Nuclear Data for Science and Technology location:Bruges, Belgium date:11 Sep - 16 Sep 2016 status: Published online

Beta-delayed neutron emission (Beta-n) is a form of radioactive decay in which an electron, an anti-neutrino and one or more neutrons are emitted. This process arises if the energy window of the decay Q_Beta is greater than the neutron separation energy S n of the daughter. The probability in each decay of emitting neutrons is called the Pn value. This form of decay plays a key role in the synthesis of chemical elements in the Universe via the rapid neutron capture process, or r-process. The r-process proceeds far from the valley of nuclear stability, and leads to very neutron-rich nuclei that then decay to the line of stability. Most of these nuclei are ßn emitters. The initial abundance distribution is shaped by the decay half-life T1/2, but the neutron emission affects the final abundances in two ways: on the one hand it shifts the decay path to lower masses and on the other hand it provides a source of neutrons for late captures that will shift it in the opposite way. Thus, a good knowledge of Pn and T1/2 values of the nuclei between the line of stability and the r-process path is needed for a correct understanding of the observed abundances. Besides the astrophysical interest, the measurement of new Pn values and half-lives is also useful for refining nuclear structure models, constraining parameters of the models and testing ß-strength functions [3]. Our current understanding of the process of ß-delayed multiple neutron emission, as well as the competition between different open channels (gamma, one-neutron, two-neutron, etc), is incomplete because of the scarcity of experimental data. With these ideas in mind, the BRIKEN (Beta-delayed-neutron-measurements at RIKEN) collaboration was established, with the aim of greatly improving the quantity and quality of data the decays of very neutron-rich nuclei close to the r-process path.

Our understanding of the evolution of the shell structure in nuclei far from stability is based on the study of some key nuclei. Nuclei at or next to double shell closures play a special role in this. Presently, a lot of discussion is concentrated on the neutron-rich calcium isotopes, which provide a rich testing ground for various nuclear models with several traditional and new magic numbers. 60 Ca is now almost within reach with the most advanced radioactive beam facilities. In order to investigate the evolution of the shell gap at N = 40, the configuration of states in the odd–even titanium isotopes up to N = 37 ( 59 Ti) have been studied. In order to experimentally access the shell gap at N = 40, it is nowadays within the reach of the most advanced facility the investigation of neutron hole configuration states in odd–even titanium isotopes up to N = 37, in the 59 Ti nucleus. Such states correspond to relatively simple configurations that constitute a challenging testing ground for effective nuclear interactions. The new data obtained in our experiment allows to place the present predictions concerning the shell closure at N = 40 in the calcium region on a more solid ground.

The β-decay half-lives of 94 neutron-rich nuclei ^{144-151}Cs, ^{146-154}Ba, ^{148-156}La, ^{150-158}Ce, ^{153-160}Pr, ^{156-162}Nd, ^{159-163}Pm, ^{160-166}Sm, ^{161-168}Eu, ^{165-170}Gd, ^{166-172}Tb, ^{169-173}Dy, ^{172-175}Ho, and two isomeric states ^{174m}Er, ^{172m}Dy were measured at the Radioactive Isotope Beam Factory, providing a new experimental basis to test theoretical models. Strikingly large drops of β-decay half-lives are observed at neutron-number N=97 for _{58}Ce, _{59}Pr, _{60}Nd, and _{62}Sm, and N=105 for _{63}Eu, _{64}Gd, _{65}Tb, and _{66}Dy. Features in the data mirror the interplay between pairing effects and microscopic structure. r-process network calculations performed for a range of mass models and astrophysical conditions show that the 57 half-lives measured for the first time play an important role in shaping the abundance pattern of rare-earth elements in the solar system.

An ambitious program to measure decay properties, primarily β-delayed neutron emission probabilities and half-lives, for a significant number of nuclei near or on the path of the rapid neutron capture process, has been launched at the RIKEN Nishina Center. We give here an overview of the status of the project.

Kinematographic traces enable an assessment of jaw movements in the sagittal and coronal planes and the relationship of centric relation to centric occlusion can be determined. Centric relation in this context does not necessarily imply the ligamentous position but rather to an actively obtained physiological border position possibly corresponding to the retruded direct contact position. This position in normal subjects is either postero-inferior to or coincident with centric occlusion. Normal subjects were able to make lateral movements of the jaws to and from centric occlusion on either side and certain subjects were able to describe a plateau in or about the horizontal position of centric occlusion. Rhythmic traces showed that opening and closing movements of the jaws could be made in about 550 msec and reflex jaw opening was usually elicited after centric occlusion had been achieved. The significant correlation coefficients found by measuring the angles of opening, terminal opening and closing indicated that jaw movement was integrated. The TMJ series differed from the normal series in nearly all phases of jaw movement recorded. Centric relation was found to be lateral and antero-inferior to centric occlusion. On the side of the first interceptive tooth contact the patient was not able to return the jaws to centric occlusion. Intermittent traces indicated that there was no significant correlation between the angles of opening, terminal opening and closing suggesting that jaw movement were incoordinated. This was reflected in rhythmic traces which were considerably longer than those of the normal series. This increase in duration was found to be due partially to centric slides and partially to asynergistic movements of the mandible. The jaw-opening reflex was not usually elicitable. It is considered that in the TMJ series centric occlusion is a strained position and is usually lateral to and postero-superior to centric relation. This relationship of centric occlusion to centric relation is the reverse of normal relations and indicates that the mandible is displaced in centric occlusion. In general, patients with the TMJ syndrome have a postero-lateral displacement of the mandible.

1. The anatomy and histology of the human temporomandibular joint indicates that the meniscus is firmly attached to the mandibular condyle and that during translatory movements the meniscus and condyle move concomitantly. The lateral pterygoid muscle, both inferior and superior heads insert into the meniscus and the pterygoid fovea of the condyle. 2. The structure of the gracilis and pars posterior indicate that these are the parts of the meniscus that are exposed to friction during jaw movement. It is suggested that during hinge movement the sagittal crest of the condyle moves from underneath the pars posterior to underneath the pars gracilis. 3. The restraining ligament for the articulation appears to be the lateral ligament. Its function is to keep the articular surfaces relatively close together during movement and to restrain lateral and posterior movements of the condyle. Its intimate association with the deep fibres of the masseter muscle appears to be important. 4. The fact that the meniscus is thicker medially than laterally would indicate that its major function is to smooth out the incongruities between the joint surfaces. 5. The sphenomandibular ligament as well as being a 'guy' ligament is intimately associated with the postero-superior medial capsular meniscal complex. The medial capsular complex would seem to contribute to the major part of the anterior ligament to the malleus. 6. Remodelling of the articular surfaces occur throughout life by progressive and regressive remodelling. However, if the remodelling processes increase, either the medio-lateral or antero-posterior dimensions of the joint an osteoarthritic condition prevails. 7. Excessive progressive remodelling appears to be due to abnormal positions of the condyle in the maximal intercuspal position. It can be caused by orthodontic procedures or by experimental displacement of the condyle. 8. The transitional zone appears to be important in the aetiology of osteoarthritis since when this zone comes under pressure proliferation of cartilage cells occur which may be transformed into bone, resulting in the hooked condyle.

In this contribution the low-excitation structural properties of the doubly mid-shell nucleus 170Dy are discussed, with a special empasis on the evolution of the ground state rotational band within the dysprosium isotopic chain. Recent results from an experiment with the EURICA setup at RIKEN are shown in the context of previous measurements at the PRISMA+CLARA as well as the PRISMA+AGATA setups at Laboratori Nazionali di Legnaro. A brief outlook on future planned measurements is also given.

We present information on the excited states in the prolate-deformed, neutron-rich nuclei 165;167Tb100;102. The nuclei of interest were synthesised following in-flight fission of a 345 MeV per nucleon 238U primary beam on a 2 mm 9Be target at the Radioactive Ion-Beam Factory (RIBF), RIKEN, Japan. The exotic nuclei were separated and identified event-by-event using the BigRIPS separator, with discrete energy gamma-ray decays from isomeric states with half-lives in the s regime measured using the EURICA gamma-ray spectrometer. Metastable-state decays are identified in 165Tb and 167Tb and interpreted as arising from hindered E1 decay from the 7 2 [523] single quasi-proton Nilsson configuration to rotational states built on the 3 2 [411] single quasi-proton ground state. These data correspond to the first spectroscopic information in the heaviest, odd-A terbium isotopes reported to date and provide information on proton Nilsson configurations which reside close to the Fermi surface as the 170Dy doubly-midshell nucleus is approached.

Background: Inter-professional education (IPE) and training to encourage collaborative teamwork in healthcare and medical teams has been widely advocated. Objectives: The aim of the study was to evaluate post-graduate students’ perceptions of the value of IPE and videos modelling good practise on multi disciplinary team (MDT) work and skill acquisition. Method: Four sports injury assessment educational videos were prepared that model high level IPE team working in the ‘Combined Clinic’ (a MDT clinic for complex patients). These were used to educate 26 doctors and physiotherapists on musculoskeletal clinical examination (MCE). The participants were then surveyed, and a sample of the group took part in semi-structured interviews that were audio-recorded and analysed by thematic content analysis.\ Results: There was an 85% response rate to the survey, with 46% of the group describing their competence in MCE as ‘developing skills,’ and 50% as having ‘some experience’. Attitudes towards IPE and MDT work were positive, acknowledging their benefits as learning tools. Thematic analysis of the interview data revealed an appreciation; of the real-time approach with expert instruction of multiple perspectives and perceived behavioural changes of improved MCE technique and enhanced interactive skills. Conclusion: This study provided evidence that an inter-professional approach can promote learning amongst postgraduate students, resulting in clinical skill acquisition. Further, the videos served to improve students’ appreciation of IPE, teamwork, and awareness of other disciplines.

Background Interprofessional education (IPE) has been used more frequently in the last thirty years to encourage collaborative teamwork within healthcare. Objectives The aims of this study were primarily to assess the impact of multimedia instruction on musculoskeletal clinical examination (MCE) skill acquisition. Secondly, to evaluate students9 perceptions of the value of IPE and multi disciplinary team (MDT) work. Method A survey was administered to a purposively sampled group of postgraduate students, comprising medical practitioners and physiotherapists (n=26). The sample was diverse in age, speciality, and MDT and IPE experience. The intervention was four sports injury assessment DVDs made by expert clinicians modelling high level interprofessional team working, made specifically for use in the study. Postintervention semi-structured interviews, conducted with a sample from the survey group (n=10) until data saturation occurred, were audio-recorded and analysed by thematic content analysis. Results An 85% survey response rate was obtained. 46% of the group described their competence in MCE as ‘developing skills’ and 50% described having ‘some experience’. Attitudes towards IPE and MDT work were highly positive; overriding beliefs were that they benefited practice by affording a range of learning opportunities. Interview analysis revealed five main themes: a real time approach with expert instruction; multiple perspectives; and diversity within the cohort; changing behaviour by improving MCE technique and enhancing interactive skills. Overriding beliefs were that observing and learning from different experts9 skilful examination under real time conditions was perceived as largely beneficial across the whole group. Conclusion This study provides evidence that interprofessional learning among postgraduate students can result in skill development – such as advanced assessments skills. Furthermore, the DVDs improved students9 appreciation of IPE, healthcare teamwork, and awareness of other disciplines. The use of DVD learning tools to teach and assist with the delivery of MCE and IPE warrants further investigation.

Random-lattice fermions have been shown to be free of the doubling problem if there are no interactions or interactions of a non-gauge nature. However, gauge interactions impose stringent constraints as expressed by the Ward-Takahashi identities which could revive the free-field suppressed doubler modes in loop diagrams. After introducing a formulation for fermions on a new kind of random lattice, we compare random, naive and Wilson fermions in two dimensional Abelian background gauge theory. We show that the doublers are revived for random lattices in the continuum limit, while demonstrating that gauge invariance plays the critical role in this revival. Some implications of the persistent doubling phenomenon on random lattices are also discussed., 16 A4 pages, UM-P-93/05

Random-lattice fermions have been shown to be free of the doubling problem if there are no interactions or interactions of a non-gauge nature. On the other hand, gauge interactions impose stringent constraints as expressed by the Ward-Takahashi identities which could revive the free-field suppressed doubler modes in loop diagrams. Comparing random lattice, naive and Wilson fermions in two dimensional abelian background gauge theory, we show that indeed the doublers are revived for random lattices in the continuum limit. Some implications of the persistent doubling phenomenon on random lattices are also discussed., 7 A4 pages, 3 figures in postcript are included

Seven cases of the erosive type of lichen planus, as well as normal tissue, were studied with the optical and electron microscope. The study was concerned with the distribution and formation of colloid bodies. These bodies were located at the epithelial-proprial junctions and occasionally inter-epithelially. They were seldom larger than basal epithelial cells and were macrophages which contained fragments of phagocytosed epithelial cells. They probably correspond to cytoid bodies which have a similar size and a similar distribution.

The intramural ganglia and chromaffin cells in guinea pig atria were examined with the electron microscope. Three possible types of synapses were identified associated with the ganglia; axo-dendritic, axo-somatic, and axo-axonal. In all cases the presynaptic nerve appeared to be cholinergic and no definite adrenergic fibres were seen in association with the ganglia. The chromaffin cells occurred in small clusters which were found both alone and in conjunction with the ganglia. The dense cored vesicles in the cytoplasm of the chromaffin cells resembled the granules in the noradrenergic cells of the adrenal medualla. No nerve terminations were found on these cells. From morphological considerations it seemed unlikely that the chromaffin cells released their contents directly into the blood.

— Electromyographic analysis was carried out prior to occlusal equilibration for patients who had some form of TMJ dysfunction and again after treatment. The results were compared with similar analyses for patients without any symptoms of dysfunction (controls) and for patients who had been wearing some kind of occlusal appliance as treatment for dysfunction. The parameters measured were the period of minimal activity (inactive phase of jaw elevators sometimes referred to as the inactive phase), the duration of muscle contraction before tooth contact (DMC), the period of muscle activity after tooth contact (latency), the inhibitory response, and the duration of the clench phase of the temporal and masseter muscles. In general the pathological series had longer cycles, longer DMC, longer clench phases and less significant correlation coefficients than the controls. The results indicated a dominance of the closing muscles in the pathological groups over the other parameters of the cycle during metronome monitoring. Also, the controls and the POST equilibration group yielded readily to cortical command. The parameters of the cycle in the POST-equilibration group were facilitated as compared to the other groups.

The purpose of the present study was to classify lymphocytes in the buccal mucosa of patients affected with recurrent apthous ulceration. Two lymphocytes were identified. The B lymphocyte was characterized by an extensive Golgi complex, an extensive tubular rough surfaced endoplasmic reticulum, and an extensive canalicular system. Usually the nucleus was electron lucent except for perinuclear condensation of chromatin. The T lymphocyte had a moderately developed Golgi complex, absent or poorly developed rough surfaced endoplasmic reticulum, lysosomes, and considerably more heterochromatin (perinuclear) than the B lymphocyte. Uropods were associated with the T lymphocyte and exerted cytotoxic effects on basal and suprabasal cells.