Experimental Study of Optimal Measurements for Quantum State Tomography.

Quantum tomography is a critically important tool to evaluate quantum hardware, making it essential to develop optimized measurement strategies that are both accurate and efficient. We compare a variety of strategies using nearly pure test states. Those that are informationally complete for all states are found to be accurate and reliable even in the presence of errors in the measurements themselves, while those designed to be complete only for pure states are far more efficient but highly sensitive to such errors. Our results highlight the unavoidable trade-offs inherent in quantum tomography.

Quantum signatures of chaos in a kicked top.

Chaotic behaviour is ubiquitous and plays an important part in most fields of science. In classical physics, chaos is characterized by hypersensitivity of the time evolution of a system to initial conditions. Quantum mechanics does not permit a similar definition owing in part to the uncertainty principle, and in part to the Schrödinger equation, which preserves the overlap between quantum states. This fundamental disconnect poses a challenge to quantum-classical correspondence, and has motivated a long-standing search for quantum signatures of classical chaos. Here we present the experimental realization of a common paradigm for quantum chaos-the quantum kicked top- and the observation directly in quantum phase space of dynamics that have a chaotic classical counterpart. Our system is based on the combined electronic and nuclear spin of a single atom and is therefore deep in the quantum regime; nevertheless, we find good correspondence between the quantum dynamics and classical phase space structures. Because chaos is inherently a dynamical phenomenon, special significance attaches to dynamical signatures such as sensitivity to perturbation or the generation of entropy and entanglement, for which only indirect evidence has been available. We observe clear differences in the sensitivity to perturbation in chaotic versus regular, non-chaotic regimes, and present experimental evidence for dynamical entanglement as a signature of chaos.

[Difficulty in diagnosis of a cardiogenic shock with thrombotic and sub-occluded LAD. A train can hide another one!] / Difficulté diagnostic d'un choc cardiogénique sur une sub-occlusion thrombotique de l'IVA. Un train peut en cacher un autre !

The pheochromocytome is a localized tumor at the level of the medullosurrenale in 85% of the cases. The clinical presentation is very variable. Severe Heart failure presentation can be the mode of revelation in 2% of the cases. We present the case of a patient admitted for refractory cardiogenic shock correlated to pheochromocytome tumor. The difficulty of this rare clinical presentation was to confirm rapidly and in emergency this diagnosis in the same time when the patient presents a persistante and severe cardiogenic chock after finding a sub-occluded and thrombotic LAD coronary artery and which was treated by thrombectomy and coronary revascularization. The surgical treatment of this tumor is considered to be a quickly saving treatment. It allows a fast recovery of the cardiac function.

Mutants of TETRAHYMENA THERMOPHILA with Temperature-Sensitive Food Vacuole Formation. I. Isolation and Genetic Characterization.

Germ-line mutants have been isolated in Tetrahymena thermophila that have recessive, temperature-sensitive defects in phagocytosis. Nitrosoguanidine-mutagenized cells were induced to undergo cytogamy, and clones were isolated that were unable to form food vacuoles after two days of growth at 39 degrees . Most of the mutants belong to a single complementation group, designated vacA. They have defects in oral development-not in phagocytosis per se-that are undetectable under light microscopy. One fertile mutant, phenotypically indistinguishable from the vacA group, has its vac mutation(s) restricted to the macronucleus, and it is a heterokaryon for two other markers. This clone probably resulted from a failure of the two gametic nuclei to fuse after normal exchange. Two additional mutants were studied, but their sterility prevented a full genetic analysis. One of these clones has a rudimentary oral apparatus and defective contractile vacuole pores; both defects may be determined by the same mutation. The other clone has a structurally normal oral apparatus and may be defective in phagocytosis per se.-The induction and characterization of germ-line mutations that affect oral development open the way for the genetic dissection of the morphogenesis of a complex eukaryotic organelle, and make available additional useful mutants for the study of nutrition and transmembrane active transport.

Pronuclear fusion failure: an alternate conjugational pathway in Tetrahymena thermophila, induced by vinblastine.

Vinblastine is shown to induce pronuclear fusion failure in conjugating Tetrahymena thermophila. In this alternate conjugational pathway gametic pronuclei are exchanged between conjugants but do not fuse. Each pronucleus undergoes one mitotic division to produce a new macro- and micronucleus. Genetic consequences of pronuclear fusion failure include the following: (1) the progeny are whole genome homozygotes with nuclei derived from single meiotic products, and (2) half of the progeny are heterokaryons with micro- and macronuclei of different genetic origins. These facts make this process extremely useful in strain construction and mutant isolation. The induction of pronuclear fusion failure by vinblastine suggests that microtubules play an essential role in pronuclear fusion.

[Women and acute coronary syndrome with ST elevation: Excess mortality related to longer delays and spontaneous coronary dissection]. / Syndromes coronariens aigus avec sus-ST chez la femme: une surmortalité liée aux délais de prise en charge et dissection coronaire spontanée.

The outcome of patients with ST elevation acute coronary syndrome (ACS) has been increasingly improving in the general population over the past few decades. However, detailed analysis of the results show that the reduction in mortality rates is higher in males compared to their female counterparts. The excess mortality rate observed in women, though sometimes questioned, has been widely reported in the literature. The higher mortality rate observed in women with ST elevation ACS can be explained by the presence of aggravating clinical factors such as older age, a higher percentage of diabetics, and a higher frequency of cardiogenic shock. Other factors pertaining to patient management seem to negatively impact the outcome. These factors include a lower use of reperfusion strategies, longer time to treatment mainly as a result of diagnostic uncertainty with respect to a disease, which is believed to affect principally the male gender. The doubts that female patients themselves and their families have about the nature of their symptoms are also present in the medical environment but cease to exist in the catheterization laboratory. This is illustrated in the first clinical case that we present here. Coronary reperfusion is the cornerstone of the therapeutic management of MI. In this context, bleeding complications associated with the implemented treatments can also result in an increased mortality rate in this more vulnerable population. When all the factors likely to influence the prognosis are taken into account, excess mortality seems to persist in women, especially in younger patients. As described in the second clinical case, a distinct physio-pathological factor, more frequent in women, could account for this higher mortality rate. Indeed, spontaneous coronary dissection and intramural hematoma are not always easy to diagnose and may not be adequately managed by reperfusion treatments. In addition, these coronary reperfusion strategies are probably not adapted to this type of ACS. It is, therefore, very important to identify them by angiography coupled with intra-coronary imaging examination when necessary and to carry out further research to adjust our PCI techniques to this pathology.

Characteristics of stably expressed human dopamine D1a and D1b receptors: atypical behavior of the dopamine D1b receptor.

Human dopamine D1a and D1b receptors were stably expressed in Baby Hamster Kidney (BHK) or Chinese Hamster Ovary (CHO) cells. [3H]SCH23390 saturation experiments indicated the presence of only a single binding site in the D1a expressing cell line with a Kd of 0.5 nM. In D1b expressing cell lines, two binding sites were observed with Kd values of 0.5 and 5 nM in CHO cells and 0.05 and 1.6 nM in BHK cells, respectively. Neither of the receptors affected Ca2+ metabolism whereas they both were coupled in a stimulatory fashion to adenylyl cyclase. The pharmacological profile of both the D1a and D1b receptors as assessed from inhibition of specific [3H]SCH 23390 binding was classical D1-like. Thus, benzazepine derivatives as well as the atypical neuroleptics, clozapine and fluperlapine, exhibited high affinity whereas D2 selective compounds like sulpiride and spiperone had low affinity for these receptors. Besides SCH 23390, only NNC 112, fluphenazine and bulbocapnine were able to discriminate between the two states of the D1b receptor. In case of the D1a receptor, the Ki values obtained in binding experiments were very similar to Ki values obtained from inhibition of dopamine stimulated adenylyl cyclase. In the D1b expressing cell line, the Ki values obtained from inhibition of the dopamine stimulated adenylyl cyclase indicated a significantly better correlation with the state of the D1b receptor showing high affinity for antagonists. In agreement with observations from binding experiments, dopamine was around 20 fold more potent in stimulating adenylyl cyclase via the D1b receptor as compared to the D1a receptor.(ABSTRACT TRUNCATED AT 250 WORDS)

[Coronary surgery of the beating heart. First year of experience in a series of 317 non-selected coronary patients]. / Chirurgie coronaire à coeur battant. Première année d'expérience sur une série de 317 patients coronariens non sélectionnés.

From May 1999 to May 2000, 317 unselected patients, representing 92.7% of all coronary artery surgery procedures, underwent open heart surgery of the beating heart by median sternotomy with the aid of a cardiac stabilising device. The main preoperative characteristics were: mean age = 66.1 years; men = 78.9%; left main stem disease = 31.8%; mean left ventricular ejection fraction = 54.1%; mean Parsonnet index = 16.9. These 317 patients were compared with a group of 303 patients who underwent coronary bypass surgery the year before by the same surgical team with cardiopulmonary bypass (CPB) and cardiac standstill. Seven hundred and eighty-six distal anastomoses were carried out in the beating heart group (2.48 grafts per patient) compared with 2.91 in the CPB group: p < 0.001). There were 10.1% single bypass, 37.5% double bypass, 47.3% triple bypass and 5% quadruple bypass procedures. A cardiopulmonary bypass was required in 13 patients (4.1%). The mortality at 30 days was 3.1% versus 4.6% in the CPB group (p = NS). The need for blood transfusion was reduced by nearly 40% in the beating heart group (23.7% versus 39.9%, p < 0.001). The incidence of cerebrovascular complications was reduced from 3% in the CPB group to 0.6% in the beating heart group (p = 0.06). The peak postoperative troponine I levels were much lower in the beating heart group (2.5 versus 6.4 ng/ml, p < 0.001). The authors conclude that surgery on the beating heart is feasible in most patients. Compared with conventional surgery under CPB, there seems to be less requirement for blood transfusion and a tendency to reduce the cerebral risk. Nevertheless, a large prospective randomised trial is required to validate the potential advantages and limitations of this technique with respect to conventional surgery and to determine the optimal indications of surgery on the beating heart.

[Granulocyte-macrophage colony-stimulating factor. Treatment of patients with highly malignant lymphomas and acute lymphoblastic leukemias after autologous bone marrow transplantation]. / Granulocyt-makrofag-kolonistimulerende faktor. Behandling af patienter med højmaligne lymfomer og akut lymfoblastleukoemi efter autolog knoglemarvstransplantation.

We have evaluated the effect of intravenous infusions of granulocyte-macrophage colony-stimulating factor (GM-CSF) in ten patients undergoing autologous bone marrow transplantation after total body irradiation (11 Gy) and cyclophosphamide (120 mg/kg) conditioning for malignant lymphomas or acute lymphoblastic leukaemias. Mild side effects related to GM-CSF were seen in six patients, of whom one chose to discontinue treatment. Compared to a historic control group consisting of six patients treated with an identical conditioning regimen, a tendency was seen towards a more rapid neutrophil regeneration and a decreased need for erythrocyte transfusions. Moreover, a statistically significant improvement in thrombocyte related parameters was demonstrated. In contrast, there were no significant differences in severe toxicity, days on i.v. antibiotics, septic episodes or duration of hospitalization. In conclusion, it seems that GM-CSF treatment is of value in patients undergoing AKMT.

[Platypnea-orthodeoxia revealed by recurrent syncope episodes]. / Platypnée-orthodéoxie révélée par des syncopes à répétition.

Platypnea-orthodeoxia is a rare clinical condition which must be examined as a differential diagnosis for any bout of faintness occurring during standing or dyspnea that is exacerbated by standing. This syndrome is often associated with a patent foramen ovale. Its physiopathology is not univocal and the association of many anatomical criteria seems to be mandatory. Contrast echocardiography confirms diagnosis and closure of the patent foramen ovale during interventional catheterization and is currently the therapeutic method of choice. After closure of the foramen ovale, clinical improvement is spectacular and durable.

Robust site-resolvable quantum gates in an optical lattice via inhomogeneous control.

The power of optical lattices for quantum simulation and computation is greatly enhanced when atoms at individual lattice sites can be accessed for measurement and control. Experiments routinely use high-resolution microscopy to obtain site-resolved images in real time, and site-resolved spin flips have been implemented using microwaves resonant with frequency-shifted target atoms in focused light fields. Here we show that methods adapted from inhomogeneous control can greatly increase the performance of such resonance addressing, allowing the targeting of arbitrary single-qubit quantum gates on selected sites with minimal cross-talk to neighbouring sites and significant robustness against uncertainty in the atom position. We further demonstrate the simultaneous implementation of different gates at adjacent sites with a single global microwave pulse. Coherence is verified through two-pulse experiments, and the average gate fidelity is measured to be 95±3%. Our approach may be useful in other contexts such as ion traps and nitrogen-vacancy centres in diamond.