Electron Correlations in an Electron Bilayer at Finite Temperature: Landau Damping of the Acoustic Plasmon

We report angle-resolved Raman scattering observations of the temperature dependent Landau damping of the acoustic plasmon in an electron bilayer system realised in a GaAs double quantum well structure. Corresponding calculations of the charge-density excitation spectrum of the electron bilayer using forms of the random phase approximation (RPA), and the static local field formalism of Singwi, Tosi, Land and Sj\"{o}lander (STLS) extended to incorporate non-zero electron temperature $T_{\rm e}$ and phenomenological damping, are also presented. The STLS calculations include details of the temperature dependence of the intra- and inter-layer local field factors and pair-correlation functions. Good agreement between experiment and the various theories is obtained for the acoustic plasmon energy and damping for $T_{\rm e} \lesssim T_{\rm F}/2$, the Fermi temperature. However, contrary to current expectations, all of the calculations show significant departures from our experimental data for $T_{\rm e} \gtrsim T_{\rm F}/2$. From this, we go on to demonstrate unambiguously that real local field factors fail to provide a physically accurate description of exchange correlation behaviour in low dimensional electron gases. Our results suggest instead that one must resort to a {\em{dynamical}} local field theory, characterised by a {\em{complex}} field factor to provide a more accurate description.Comment: 53 pages, 16 figure

Temperature dependence of the EPR linewidth of Yb3+ - ions in Y0.99Yb0.01Ba2Cu3OX compounds: Evidence for an anomaly near TC

Electron paramagnetic resonance experiments on doped Yb3+ ions in YBaCuO compounds with different oxygen contents have been made. We have observed the strong temperature dependence of the EPR linewidth in the all investigated samples caused by the Raman processes of spin-lattice relaxation. The spin-lattice relaxation rate anomaly revealed near TC in the superconducting species can be assigned to the phonon density spectrum changesComment: 10 pages, 4 figures Renewed versio

Josephson array of mesoscopic objects. Modulation of system properties through the chemical potential

The phase diagram of a two-dimensional Josephson array of mesoscopic objects is examined. Quantum fluctuations in both the modulus and phase of the superconducting order parameter are taken into account within a lattice boson Hubbard model. Modulating the average occupation number $n_0$ of the sites in the system leads to changes in the state of the array, and the character of these changes depends significantly on the region of the phase diagram being examined. In the region where there are large quantum fluctuations in the phase of the superconducting order parameter, variation of the chemical potential causes oscillations with alternating superconducting (superfluid) and normal states of the array. On the other hand, in the region where the bosons interact weakly, the properties of the system depend monotonically on $n_0$. Lowering the temperature and increasing the particle interaction force lead to a reduction in the width of the region of variation in $n_0$ within which the system properties depend weakly on the average occupation number. The phase diagram of the array is obtained by mapping this quantum system onto a classical two-dimensional XY model with a renormalized Josephson coupling constant and is consistent with our quantum Path-Integral Monte Carlo calculations.Comment: 12 pages, 8 Postscript figure

Послеоперационная наружная трансабдоминальная гиперлимфорея (клиническое наблюдение)

Massive lymphorrhea can cause severe dysfunction of organs and systems and result in death due to loss of vital metabolites from the bodyAim. To demonstrate low efficacy of conservative therapy and late lymph duct ligation in continuous massive postoperative lymphorrhea.Results. We treated a patient with previous subtotal gastric resection with single-plane pancreatic resection, D2 lymph node dissection, peritoneal draining due to poorly differentiated carcinoma in the lower third of stomach and total hysterectomy who developed external lymphorrhea through peritoneal drainage tubes 3 days after surgery. A fat-rich diet, endolymphatic sodium etamsylate administration, and lymphatic duct ligation were not successful in terminating the lymph leakage. Despite the intensive care including extracorporeal detoxification, the multi-organ failure progressed and on day 28 after the surgery the patient was pronounced dead.Conclusion. Damage to lymph ducts and lymph nodes can be complicated by massive lymphorrhea. If the source of lymphorrhea can be identified, an urgent surgical intervention is warranted to stop the lymph leakage, as well as the restoration of homeostasis to replenish the lost metabolites and prevent death of the patient.Массивная лимфорея приводит к тяжелым нарушениям функции органов и систем и, вследствие удаления с лимфой из организма жизненно важных метаболитов, может закончиться летальным исходом.Цель. Показать клиническую неэффективность консервативной терапии и позднего лигирования лимфатического протока при продолжительной и массивной послеоперационной лимфорее.Результаты. Наблюдали больную после дистальной субтотальной резекции желудка с плоскостной резекцией поджелудочной железы, лимфодиссекции D2, дренирования брюшной полости по поводу низкодифференцированного рака нижней трети желудка (T4aNoMo) и тотальной гистерэктомии, у которой через 3 дня после операции развилась наружная лимфорея через дренажи в брюшной полости. Богатая жирами диета, эндолимфатическое введение этамзилата натрия, прошивание лимфатического протока не привели к прекращению истечения лимфы. Несмотря на проводимую интенсиную терапию, включая методы экстракорпоральной детоксикации, прогрессировали проявления полиор-ганной недостаточности и на 28-е сутки после операции констатировали смерть больной.Заключение. Повреждение лимфатических сосудов и лимфоузлов может осложниться массивной лимфореей при выявлении источника которой необходимо как срочное оперативное вмешательство, направленное на остановку лимфорагии так и коррекция гомеостаза с целью восполнения потерянных организмом метаболитов и предупреждения летального исхода