Chiral symmetry, Confinement and Nuclear Matter properties

We discuss the possible influence of fundamental QCD properties such as spontaneous chiral symmetry breaking and nucleon substructure on nuclear matter properties. We propose a chiral version of the relativistic $\sigma-\omega$ model in which the attractive background scalar field is associated with the chiral invariant field governing the radial fluctuations of the quark condensate. Nuclear matter stability is ensured once the scalar response of the nucleon depending on the quark confinement mechanism is properly incorporated. The needed parameters are estimated from lattice results and a satisfactory description of bulk properties follows, the only really free parameter being the $\omega NN$ coupling constant. Pion loops can be also incorporated to obtain in a consistent way the finite density chiral susceptibilities. A good description of the asymmetry energy is obtained once the full rho meson exchange and Fock terms are included.Comment: Lecture given by G. Chanfray at the Theoretical Nuclear Physics School, 8-17 may 2007, Les Houches, Franc

Cyclic Voltammetric Experiment - Simulation. Comparisons of the Complex Mechanism Associated with Electrochemical Reduction of Zr4+ in LiCl-KCl Eutectic Molten Salt

Nuclear energy increasingly represents an important option for generating largely clean CO2-free electricity and zirconium is a fission product that is expected to be present in irradiated fuels. The present investigation addresses the electrochemical reduction of Zr4+ to Zro in LiCl - KCl eutectic molten salt in the temperature range 425–550◦C using cyclic voltammetry (CV), square-wave voltammetry (SWV) and bulk electrolysis. Simulations of the CV data indicate that the initial reduction proceeds through surface confined steps: Zr4+* + 2e− ↔Zr2+* and Zr2+* + 2e− ↔Zr* processes (* adsorbed species) followed by a peak-shaped complex diffusion controlled step that consists of a combination of closely spaced processes associated with the reactions Zr4+ + 4e− →Zr and Zr4+ + 3e− →Zr+*. Zr+*, probably in the form of ZrCl* is then further reduced to Zro* at even more negative potentials. The simulations provide the first quantitative analysis of the thermodynamics and kinetics of the Zr4+ reduction in the LiCl-KCl eutectic

Female common lizards (Lacerta vivipara) do not adjust their sex-biased investment in relation to the adult sex ratio.

Sex allocation theory predicts that facultative maternal investment in the rare sex should be favoured by natural selection when breeders experience predictable variation in adult sex ratios (ASRs). We found significant spatial and predictable interannual changes in local ASRs within a natural population of the common lizard where the mean ASR is female-biased, thus validating the key assumptions of adaptive sex ratio models. We tested for facultative maternal investment in the rare sex during and after an experimental perturbation of the ASR by creating populations with female-biased or male-biased ASR. Mothers did not adjust their clutch sex ratio during or after the ASR perturbation, but produced sons with a higher body condition in male-biased populations. However, this differential sex allocation did not result in growth or survival differences in offspring. Our results thus contradict the predictions of adaptive models and challenge the idea that facultative investment in the rare sex might be a mechanism regulating the population sex ratio

Risk factors for comorbid epilepsy in patients with psychogenic non-epileptic seizures. Dataset of a large cohort study

Psychogenic non-epileptic seizures (PNES) are the main differential diagnosis of pharmacorresistant epilepsy. Achieving the certainty in the diagnosis of PNES may be challenging, especially in the 10-22% of cases in which PNES and epilepsy co-exist. This difficulty hampers the management of these patients. Unfortunately, published series with this combined pathology are scarce and small in size. This article presents the dataset of our article “Factors associated with comorbid epilepsy in patients with psychogenic non-epileptic seizures: a large cohort study” (Massot-Tarrús et al. 2022). It is composed by a detailed demographic and clinical data of 271 consecutive patients diagnosed with PNES in our epilepsy monitoring unit (EMU) between May 2001 and February 2011, and followed until September 2016. Based on the clinical, neuroimaging and vEEG findings, 47 of these patients were diagnosed with definite comorbid epilepsy, and 30 with possible or probable comorbid epilepsy. All data was collected retrospectively from chart review. The cohort is depicted by means of demographic variables; age at PNES onset; years with PNES; frequency of PNES; duration of longest PNES seizure; self-reported history of minor head trauma (not associated with an increased risk of epilepsy) immediately preceding the first PNES; history of substance abuse; past or present history of active suicidal ideation; neuropsychological evaluation with the Minnesota Multiphasic Personality Inventory test; number and nature of risk factors for epilepsy; co-morbid degenerative brain disease or other neurological or psychiatric medical conditions; semiology of the seizures and triggers; EEG findings; type of epilepsy; number of past EMU admissions and epilepsy clinic visits and re-referrals; number of Anti-Seizure Medications (ASM) at EMU admission and discharge; and the outcome of the spells and ASM after the EMU discharge. Those ASM prescribed for reasons other than the treatment of the seizures (e.g., psychiatric disorders, migraine, pain syndromes, etc.) were not counted. The presented baseline data can be used in studies evaluating the characteristics of patients with PNES and comorbid epilepsy, and in the creation of algorithms to identify them. It could facilitate the prioritization of this subgroup of patients for prolonged video-EEG monitorization to confirm the co-existence of both types of seizures and treat them accordingly

Subjective Postural Vertical and Adolescent Idiopathic Scoliosis (AIS)

ObjectiveThe origin of the AIS is unknown. Several studies in AIS have shown disturbances of orthostatic postural control and somatosensory modality. The orthostatic postural control is the ability to organize the upright position on the earth-vertical, by multisensory central integration, especially somatosensory information. Our hypothesis is that the somatosensory disturbances in the AIS involve change in the organization of orthostatic postural control, around an erroneous central representation of verticality. Our objective is to test, in the AIS, the existence of a disturbance of the somatosensory modality in orthostatic postural control by measuring the Subjective Postural Vertical (SPV).MethodsUncontrolled preliminary study on 8 adolescents with SIA (7 girls, 13.8±0.83 years, 38.8±10.4°angle). Test=SPV measurement, vision obscured, head-trunk-members strapped, sitting on a seat, fixed to a German vertical wheel athletic gymnastics (external diameter: 1.90 m), with electronic inclinometer that measures the rotational tilt of the seat, with reference to the gravitational vertical. From 45° inclination, the subject is tilted (1°/sec) and evaluates the alignment with the vertical gravitational.ResultsAIS SPV=7.48±4.86° with a tilt predominance to the right. It is impossible to realize statistical evaluation in this preliminary study. Our results are comparable with those reported in pusher patient.DiscussionThis preliminary study shows a disturbance in the assessment of SPV in the AIS. Disorders of the central integration of somatosensory modality could explain this result.The authors are grateful to the Harps Association's members, for their helpful comments

Un Spongiaire Sphinctozoaire colonial apparenté aux constructeurs de récifs triasiques survivant dans le bathyal de Nouvelle-Calédonie

Un second représentant actuel des Sphinctozoaires, importants constructeurs de récifs au Permo-Trias, a été découvert dans la zone bathyale de la NouvelleCalédonie. Contrairement au survivant déjà connu, #Valecetia crypta$, il a conservé le mode de croissance colonial et les capacités constructrices de ses analogues fossiles. Sa croissance est bien plus lente que celle des coraux récifaux actuels. La base d'une construction de 10 cm d'épaisseur a été datée de 700 ans. (Résumé d'auteur