Impossibility of distant indirect measurement of the quantum Zeno effect

We critically study the possibility of quantum Zeno effect for indirect measurements. If the detector is prepared to detect the emitted signal from the core system, and the detector does not reflect the signal back to the core system, then we can prove the decay probability of the system is not changed by the continuous measurement of the signal and the quantum Zeno effect never takes place. This argument also applies to the quantum Zeno effect for accelerated two-level systems, unstable particle decay, etc.Comment: 14 pages, 2 figure

Small, Medium and Large Farms In The North Central Region: A Statistical Profile

Extension specialists are often challenged to design programs that meet the needs of certain classes of farmers, such as small, medium or large-scale operators. The purpose of this paper is to summarize and compare characteristics of three size groups of farms in the North Central Region, as background for a thorough discussion of how extension specialists can meet the needs of each of these groups..

Myomectomy as a pregnancy-preserving option in the carefully selected patient

Objectives: To present the indications for myomectomy during pregnancy and to discuss complications possibly related and unrelated to the procedure. Method and Results: A 33-year-old patient at 18 weeks of gestation underwent removal of a 1,570-gram symptomatic fundic myoma. Histologically the patient had a leiomyomatous neoplasm of uncertain malignant potential. The pregnancy was continued under sequential observation with magnetic resonance imaging and ultrasound. At 36 weeks of gestation a healthy girl with an upper extremity limb defect was born via cesarean section. Follow-up of the mother and the child was uneventful. Conclusions: Certain known risk factors in pregnant women with myomas can predispose to complications during pregnancy. Women with such risk factors or women who have failed medical therapy should be offered the option of undergoing myomectomy as a pregnancy-preserving procedure. Copyright (C) 2002 S. Karger AG, Basel

Self-induced decoherence approach: Strong limitations on its validity in a simple spin bath model and on its general physical relevance

The "self-induced decoherence" (SID) approach suggests that (1) the expectation value of any observable becomes diagonal in the eigenstates of the total Hamiltonian for systems endowed with a continuous energy spectrum, and (2), that this process can be interpreted as decoherence. We evaluate the first claim in the context of a simple spin bath model. We find that even for large environments, corresponding to an approximately continuous energy spectrum, diagonalization of the expectation value of random observables does in general not occur. We explain this result and conjecture that SID is likely to fail also in other systems composed of discrete subsystems. Regarding the second claim, we emphasize that SID does not describe a physically meaningful decoherence process for individual measurements, but only involves destructive interference that occurs collectively within an ensemble of presupposed "values" of measurements. This leads us to question the relevance of SID for treating observed decoherence effects.Comment: 11 pages, 4 figures. Final published versio

Atom-molecule coexistence and collective dynamics near a Feshbach resonance of cold fermions

Degenerate Fermi gas interacting with molecules near Feshbach resonance is unstable with respect to formation of a mixed state in which atoms and molecules coexist as a coherent superposition. Theory of this state is developed using a mapping to the Dicke model, treating molecular field in the single mode approximation. The results are accurate in the strong coupling regime relevant for current experimental efforts. The exact solution of the Dicke model is exploited to study stability, phase diagram, and nonadiabatic dynamics of molecular field in the mixed state.Comment: 5 pages, 2 figure

Semiclassical limit of the entanglement in closed pure systems

We discuss the semiclassical limit of the entanglement for the class of closed pure systems. By means of analytical and numerical calculations we obtain two main results: (i) the short-time entanglement does not depend on Planck's constant and (ii) the long-time entanglement increases as more semiclassical regimes are attained. On one hand, this result is in contrast with the idea that the entanglement should be destroyed when the macroscopic limit is reached. On the other hand, it emphasizes the role played by decoherence in the process of emergence of the classical world. We also found that, for Gaussian initial states, the entanglement dynamics may be described by an entirely classical entropy in the semiclassical limit.Comment: 8 pages, 2 figures (accepted for publication in Phys. Rev. A

Anthrazykline und Herceptin® als neue Therapieoption beim metastasierten Mammakarzinom

Single-agent treatment with the humanized monoclonal antibody trastuzumab (herceptin) has shown remarkable activity in patients with metastatic breast cancer overexpressing the HER-2/neu proto-oncogen. Further significant advances could be achieved with the combined use of herceptin and paclitaxel or doxorubicin/cyclophosphamide. However, cardiotoxicity remains a significant and thus far unresolved problem of the herceptin-doxo-rubicin combination. Thus, several studies have recently been initiated to identify equally effective but less toxic first-line regimens. Epirubicin, the taxanes paclitaxel and docetaxel, Navelbine(R), cisplatin, and Caelyx(R), a liposomal encapsulated formulation of doxorubicin, were selected for combination with herceptin in these studies because the appeared the most promising agents

Learning from each other: A handbook for language teacher associations

The publication is aimed at those involved in the running of language teacher associations at international, national, regional and local levels. This may include paid employees or, more frequently, volunteers. It provides guidance on the effective running and networking of associations. It encourages language teacher associations to collaborate in order to support teachers more effectively, and to contribute to improvements in the quality of language teaching. It enables language teachers across the world to share their own ideas, to be involved in research, and to learn about the cutting-edge work of the ECML and its European project

Retrospektive Analyse zur Dosisintensität von Epirubicin beim Mammakarzinom

Objective: In breast cancer the efficacy of epirubicin-based chemotherapy is possibly related to the actual dose intensity applied. We retrospectively determined the administered dose intensity and the relative toxicity and efficacy of an epirubicin-containing regimen in patients with primary or metastatic breast cancer. Patients and Methods: Fluorouracil, epirubicin, and cyclophosphamide (FEC) were either given at a standard dose of 500/50/500 mg/m(2) (FE50C) or at an intensified dose of 500/75/500 mg/m(2) (FE75C) every 3 weeks. Of the 66 patients treated, 63 were evaluable; 43 had metastatic breast cancer, and 20 patients with an increased risk of relapse received FEC as an adjuvant treatment. Results: Dose intensity and absolute dose of adjuvant treatment were 81 and 70% for FE50C and 96 and 88% for FE75C In metastatic breast cancer, the dose intensity for FE50C was 94% and for FE75C 92%. In a retrospective comparison, the 4-year overall survival following adjuvant FE50C and FE75C was 40 and 48%, respectively (p = 0.47). The dose intensification led to a higher response rate of 34 vs. 44%. There were no significant differences in response duration and survival time. The toxicity profiles were comparable between FE50C and FE75C Conclusions: In genera I, the doses applied were lower than initially planned. Higher doses of epirubicin did not result in a significant increase of toxicity. Despite the limitations of a retrospective analysis, our observations support the importance of adherence to the planned dose intensity as a prerequisite for optimal treatment of patients suffering from breast cancer. As our results could be related to selection bias, dose-intensified anthracycline-containing regimens should be further evaluated in prospective trials. Copyright (C) 2001 S. Karger AG, Basel

Therapie bei Progression und Rezidiv des Ovarialkarzinoms

Secondary surgery after failure of primary treatment is a promising and reasonable option only for patients with a relapse-free interval of at least 6-12 months who should have ideally achieved a tumor-free status after primary therapy. As after primary surgery, size of residual tumor is the most significant predictor of survival after secondary surgery. Even in the case of multiple tumor sites, complete removal of the tumor can be achieved in nearly 30% of the patients. Treatment results are much better in specialized oncology centers with optimal interdisciplinary cooperation compared with smaller institutions. Chemotherapy can be used both for consolidation after successful secondary surgery and for palliation in patients with inoperable recurrent disease. Since paclitaxel has been integrated into first-line chemotherapy, there is no defined standard for second-line chemotherapy. Several cytotoxic agents have shown moderate activity in this setting, including treosulfan, epirubicin, and newer agents such as topotecan, gemcitabine, vinorelbine, and PEG(polyethylene glycol)-liposomal doxorubicin. Thus, the German Arbeitsgemeinschaft Gynakologische Onkologie (AGO) has initiated several randomized studies in patients with recurrent ovarian cancer in order to define new standards for second-line chemotherapy