Macroscopic quantum coherence of the spin triplet in the spin-ladder compound Sr14Cu24O41.

We report the direct observation by inelastic neutron scattering experiments of a spin triplet of magnetic excitations in the response associated with the ladders in the composite cuprate Sr14Cu24O41. This appears as a peak at q(Q1D)=π and energy Δ1=32.5 meV, and we conjecture that all the triplets making up this conspicuous peak have the same phase and therefore interpret it as the signature of the occurrence of quantum coherence along the ladder direction between entangled spin pairs. From the comparison with previous neutron and x-ray data, we conclude that the temperature evolution of this mode is driven by the crystallization of holes into a charge density wave in the ladder sublattice.

Prediction of the acoustic form function by neural network techniques for immersed tubes.

A new approach is used to predict the acoustic form function (FF) for an infinite length cylindrical shell excited perpendicularly to its axis using the artificial neural network (ANN) techniques. The Wigner-Ville distribution is used like a comparison tool between the FF calculated by the analytical method and that predicted by the ANN techniques for a stainless steel tube. During the development of the network, several configurations are evaluated for various radius ratios ba (a: outer radius: b: inner radius of the tube). The optimal model is a network with one hidden layer. It is able to predict the FF with a mean relative error about 1.61% for the cases studied in this paper.

[Cerebral hydatic cyst and psychiatric disorders. Two cases]. / Kyste hydatique cérébral et troubles psychiatriques. A propos de deux cas.

The hydatidosis is an endemic illness in regions of the Middle Orient, Mediterranean, south of America, north Africa and the Australia. The preferential localization of cyst hydatic is the liver (48%), the lung (36%) and in 6% of cases it localizes in unaccustomed place as the brain. Intracerebral localization is relatively rare, its impact is 1 to 5% of all cases of hydatidose. This localization is the child's appendage with a masculine predominance. The cyst hydatic intracranien is often lone, of localization usually supratentorielle, sometimes infratentorielle. Symptoms are especially the diffuse headache associated to various neurological signs in relation with sits of the tumor. The psychiatrics symptoms depends on its localization, sides, intracranial hypertension, and the previous personality. In 15 to 20% of cases these tumors can appear in the beginning of their evolution by the isolated psychiatric symptoms. We report the case of two patients that have been hospitalized first in the Academic Psychiatric Unit of Marrakech for isolates psychiatric disorders and whose scanning revealed the presence of cerebral hydatic cyst and that required a surgical intervention in neurosurgery. Case 1 - Patient 29 years old, bachelor, uneducated, leaving in country outside, fermar, in permanent contact with dogs. No particular medical history. The patient has been brought by his family to the psychiatric emergencies after behavior disorders. The beginning of his symptomatology was one year ago by behavior disorders: instability, violence, isolation, and a corporo-sartorial carelessness. His symptomatology worsened and the patient became very aggressive. In psychiatric unit, he was disregarded, sad, anguished, indifferent to his state, very dissonant, completely detached, depersonalized. He brought back some visual and auditory hallucinations with attitude of monitoring. He was raving with delirium of persecution, of ideas of reference and delirium of bewithment. He was unconscious of his disorders. The patient has first been put under classical neuroleptic 9 mg/day of Haloperidol and 200 mg/day of chlorpromazine. The diagnosis of schizophrenia has been kept according to criteria of DSM IV. The PANSS (Positive and Negative Syndrome Scale) was to 137 (score on a positive scale was to 34, score on a negative scale was to 35 and the general psychopathologie scale was to 58). One week after his hospitalization, he developed headache with subconfusion, a cerebral scanning has been made in emergency and showed a voluminous cyst in oval foramen compressing the mesencephalon strongly. The cyst was well limited, hypodense, not taking the contrast, and without intracerebral oedema, the diagnosis of cerebral hydatic cyst has been made. The complementary exploration didn't show any other localizations, and biologic exam results didn't show any particular anomalies. The patient has been operated in neurosurgery. The immediate evolution was favorable with disappearance of confusion and absence of complications. The patient was lost of view. Six months after, the patient has been readmitted to the psychiatric emergency. He dropped his neuroleptic treatment. He was aggressive, raving, hallucinated and depersonalized. The global score to the PANSS was 63. He has been put back under neuroleptics. Three weeks after improvement and passage of the PANSS to 30, the patient went out. We couldn't have a cerebral scanner of control because the patient had no medical assurance and no money for cerebral scanner. Case 2 - Patient aged of 53 years, father of four children, uneducated, native and resident of Marrakech, confectioner as profession. He is in contact with dogs since 12 years. He has been brought to the psychiatric emergencies by his family after an agitation. The history of his illness seemed to go back at eight months ago, by the progressive apparition of an instability, sleep disorders, hostility, associated with an emotional lability. To the interview he was agitated and had a delirium of persecution. He was convinced that his wife and his children plotted against him. He had sad mood. He was anguished and had auditory and visual hallucinations. The patient was not confused but it had a hypoproxie, an fixing amnesia, a disorders of judgment and a light left hemiparesia. Cerebral scanner revealed three cerebral cyst. The first measuring 42 x 40 mm, sitting at the level parietal right, to the contact of the occipital horn, dragging his/her/its amputation and an effect of mass on ventricle homolateral, the median line and ventricle controlateral. The two other, at the level of the center semi oval, behind the first, measuring 23 mm and 15 mm on the big axis. The patient has been addressed in neurosurgery. He had a completeray exploration to search other localizations. The thoracic x-ray showed 2 pulmonary cyts. The abdominal scan and imagery by magnetic resonance showed liver cyst, peri-heart cyst and mediastinal cyst. The patient has been operated for these three cysts with good recuperation on the psychiatric and neurological symptoms. He has been addressed in heart surgery for the heart localization. The hydatidose is an endemic illness in Morocco and constitute a public health problem. The cerebral localization is rare and appear by signs of cerebral hypertension and signs of focusing. The psychiatric demonstrations are rare but preserve a major interest, by the therapeutic measure specificity that they impose. Of course, the surgical ablation of the tumor can be sufficient to attenuate the psychiatric symptoms but the recourse to a specific treatment can prove to be necessary to act on the precise targets. We are conscious of the methodological difficulties that present these 2 cases but there are unfortunately due to the financial difficulties of our patients.

Ultrasonic characterization of the quality of an epoxy resin polymerization.

This work concerns monitoring the polymerization of an epoxy resin and its hardener. An ultrasonic pulse echo technique was used to monitor the attenuation, the phase velocity, and the acoustic impedance of the resin as a function of time. The first two parameters give information about the average state of the hardening of the resin itself. The third parameter, acoustic impedance, indicates the state of the hardening of the resin at the interface with the vessel. These parameters are determined from spectral properties of echoes extracted from the experimental echo waveforms. Experiments were made for different proportions of hardener and allowed a determination of the best mixture (10% of hardener) that corresponds to the manufacturer's recommended value. Analysis of the results shows a progressive hardening from the center of the resin toward the walls of the vessel.

Oxygen Isotope Effect and Structural Phase Transitions in La2CuO4-Based Superconductors.

The oxygen isotope effect on the superconducting transition temperature (alpha(o)) varies as a function of x in La2-xSrxCuO(4) and La2-xBaxCuO(4), with the maximum alpha(o) values (alpha(o) >/= 0.5) found for x near 0.12. This unusual x dependence implies that the isotope effect is influenced by proximity to the Abma --> P4(2)/ncm structural phase transition in these systems. Synchrotron x-ray difaction measurements reveal little change in lattice parameters or orthorhombicity due to isotope exchange in strontium-doped materials where alpha(o) > 0.5, eliminating static structural distortion as a cause of the large isotope effects. The anomalous behavior of alpha(o) in both strontium- and barium-doped materials, in combination with the previously discovered Abma --> P4(2)/ncm structural phase-transition in La(1.88)B(0.12)CuO(4), suggests that an electronic contribution to the lattice instability is present and maximizes at approximately 1/8 hole per copper atom. These observations indicate a dose connection between hole doping of the Cu-O sheets, tilting instabilities of the CuO(6) octahedra, and superconductivity in La(2)CuO(4)-based superconductors.