SU(4) symmetry in the extended proton-neutron interacting boson model: multiplets and symmetry breaking

The manifestation of $SU(4)$ symmetry within an interacting boson model including particle-like and hole-like $\pi$- and $\nu$-bosons is shown for light nuclei around the Z=N=8 shell. We also present a consistent description of the particle-hole (intruder spin or $I$ spin) multiplets in the Extended Interacting Boson Model (EIBM) and of $\pi$-$\nu$ ($F$ spin) multiplets in the IBM-2 as a breaking of this $SU(4)$ symmetry

New particle-hole symmetries and the extended interacting boson model

We describe shape coexistence and intruder many-particle-hole (mp-nh)excitations in the extended interacting boson model EIBM and EIBM-2,combining both the particle-hole and the charge degree of freedom.Besides the concept of I-spin multiplets and subsequently $SU(4)$ multiplets, we touch upon the existence of particle-hole mixed symmetry states. We furthermore describe regular and intrudermany-particle-hole excitations in one nucleus on an equal footing, creating (annihilating) particle-hole pairs using the K-spin operatorand studying possible mixing between these states. As a limiting case,we treat the coupling of two IBM-1 Hamiltonians, each decribing the regular and intruder excitations respectively, in particular lookingat the $U(5)$-$SU(3)$ dynamical symmetry coupling. We apply such coupling scheme to the Po isotopes

Enquête épidémiologique sur la santé bucco-dentaire à Fada N’Gourma (Burkina Faso)

In 1983 an investigation involving a homogeneous population sample from a western city of Burkina Faso has been performed in 1983 in order to estimate the oral health status of the population cut off from any dental assistance and to assess the importance of traditional practices in the city.The investigation, performed using World Health Organization techniques (WHO, 1977) involved 354 subjects, male and female, divided into age groups from 10 to 54. It was shown that: although the oral hygiene level was very low and no dental treatments were performed, caries level was very low - although gingivitis rate was high, advanced periodontitis rate was low - The frequency of interincisive diastema (one subject out of 4 in the 15-19 age group), the progressive decline of tooth cutting, a traditional practice, in town people but the large extent of cola use (one adult out of two).The present data will be used as base-line reference to evaluate the incidence of a dental care and prevention program which has just started in the same city of Burkina Faso.En 1983, une enquête portant sur un échantillon homogène d’une ville de l’Ouest du Burkina Faso a été menée par l’Aide Odontologique Internationale pour évaluer l’état bucco-dentaire d’une population, en l’absence de service odontologique organisé, et l’incidence de pratiques traditionnelles dans cette population citadine.L’enquête, menée selon la méthode proposée par l’Organisation Mondiale de la Santé (OMS, 1977), a porté sur 354 sujets des deux sexes, répartis par tranches d’âge de 10 à 54 ans. Elle a montré: un indice de carie très bas, malgré une très mauvaise hygiène orale et l’absence de soins dentaires - un taux de prévalence des parodontopathies avancées peu élevé comparativement à celui de la gingivite - la fréquence d’une particularité orthodontique, le diastème interincisif (1 sujet sur 4 dans la tranche d’âge 15-19 ans) - la disparition progressive d’un rite traditionnel, les tailles dentaires, dans la population citadine, mais la proportion importante (1 adulte sur 2) d’utilisateurs de la noix de cola, utilisée comme excitant.La présente enquête est destinée à servir de base de comparaison au terme d’un programme de soins et de prévention bucco-dentaires mis en place actuellement

Shape coexistence in atomic nuclei and its spectroscopic fingerprints

In the present discussion we concentrate on shape coexistence asobtained within a deformed single-particle field as well as startingfrom the spherical shell-model, incorporating deformationeffects via the residual proton-neutron quadrupole interaction. Wediscuss in particular the appearance of shape coexisting phenomena inthe Pb region. In a second part then, we present a number ofexperimental fingerprints that allow to recognize the appearance ofshape coexisting phenomena or of shape mixing through the use ofselective experiments (e.g. band structure, spectroscopic factors,static moments, E0 properties and alpha-decay)

Particle-hole excitations in the interacting boson model; 4, the U(5)-SU(3) coupling

In the extended interacting boson model (EIBM) both particle- and hole-like bosons are incorporated to encompass multi-particle-multi-hole excitations at and near to closed shells.We apply the group theoretical concepts of the EIBM to the particular case of two coexisting systems in the same nucleus exhibiting a U(5) (for the regular configurations) and an SU(3) symmetry (for the intruder configurations).Besides the description of ``global'' symmetry aspects in terms of I-spin , also the very specific local mixing effects characteristic for the U(5)-SU(3) symmetry coupling are studied.The model is applied to the Po isotopes and a comparison with a morerealistic calculation is made

CT-guided iodine-125 seed permanent implantation for recurrent head and neck cancers

<p>Abstract</p> <p>Background</p> <p>To investigate the feasibility, and safety of ¹²⁵I seed permanent implantation for recurrent head and neck carcinoma under CT-guidance.</p> <p>Results</p> <p>A retrospective study on 14 patients with recurrent head and neck cancers undergone ¹²⁵I seed implantation with different seed activities. The post-plan showed that the actuarial D90 of ¹²⁵I seeds ranged from 90 to 218 Gy (median, 157.5 Gy). The follow-up was 3 to 60 months (median, 13 months). The median local control was 18 months (95% CI, 6.1-29.9 months), and the 1-, 2-, 3-, and 5- year local controls were 52%, 39%, 39%, and 39%, respectively. The 1-, 2-, 3-, and 5- survival rates were 65%, 39%, 39% and 39%, respectively, with a median survival time of 20 months (95% CI, 8.7-31.3 months). Of all patients, 28.6% (4/14) died of local recurrence, 7.1% (1/14) died of metastases, one patient died of hepatocirrhosis, and 8 patients are still alive to the date of data analysis.</p> <p>Conclusion</p> <p>CT-guided ¹²⁵I seed implantation is feasible and safe as a salvage or palliative treatment for patients with recurrent head and neck cancers.</p

The acute effects of cocoa flavanols on temporal and spatial attention

In this study, we investigated how the acute physiological effects of cocoa flavanols might result in specific cognitive changes, in particular in temporal and spatial attention. To this end, we pre-registered and implemented a randomized, double-blind, placebo- and baseline-controlled crossover design. A sample of 48 university students participated in the study and each of them completed the experimental tasks in four conditions (baseline, placebo, low dose, and high-dose flavanol), administered in separate sessions with a 1-week washout interval. A rapid serial visual presentation task was used to test flavanol effects on temporal attention and integration, and a visual search task was similarly employed to investigate spatial attention. Results indicated that cocoa flavanols improved visual search efficiency, reflected by reduced reaction time. However, cocoa flavanols did not facilitate temporal attention nor integration, suggesting Potential underlying mechanisms are discussed

The influence of different concentrations of flavanol chocolate bars under acute supplement conditions on exercise and performance

The purpose of this study was to assess the effects and acute dosage of different flavanol concentrations in a dark chocolate bar on physiological parameters during steady state (SS) and incremental exercise. In a double-blind, randomised, crossover study, 15 healthy participants with a mean ± SD age of 30 ± 7 years; stature 176.8 ± 8.6 cm and body mass 80.3 ± 8.4 kg supplemented with high flavanol (HF) (1060 mg), moderate flavanol (MF) (746 mg), low flavanol (LF) (406 mg), or a control (CON) (88 mg) chocolate bar (~ 34 g), 2 h prior to 40 min of SS cycling (80% gas-exchange threshold) followed by an incremental test to volitional fatigue. During the SS cycle oxygen consumption ([Formula: see text]), respiratory exchange ratio (RER) and heart rate (HR) were continuously monitored. Plasma samples were collected prior to commencing exercise to determine nitrate (NO ) and nitrite (NO ) levels under each condition. There was no observed effect between flavanol concentrations on [Formula: see text], RER, and HR during SS cycling (P > 0.05). [Formula: see text], peak power, HR peak, and RER peak also did not significantly differ between conditions (P > 0.05). There was a small trend for higher plasma NO levels following higher flavanol concentration; however, this did not reach statistical significance (P > 0.05). Acute supplementation with cocoa of differing flavanol concentrations does not appear to have any effect on exercise and performance. It is plausible that longer flavanol supplementation periods might have greater accumulative effects and thus may potentially elicit a larger effect