5,958 research outputs found

    Quantum erasure in the presence of a thermal bath: the effects of system-environment microscopic correlations

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    We investigate the role of the environment in a quantum erasure setup in the cavity quantum electrodynamics domain. Two slightly different schemes are analyzed. We show that the effects of the environment vary when a scheme is exchanged for another. This can be used to estimate the macroscopic parameters related to the system-environment microscopic correlations.Comment: 10 pages, 2 figure

    Hyperpigmentation associated with hormonal contraceptive use

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    Introduction: Melanocytes are cells which are present in the human skin and they are responsible for the melanin production. They can be found in the basal stratum of the epidermis and they have some prolongations extending until the stratum corneum. Melanin synthesis may increase in the presence of some factors and some irregular brownish spots – hyperpigmentations – may appear. Factors which can trigger melanogenesis are excessive sun exposure, hormonal contraception, hormonal reposition therapy, pregnancy, medicines, cosmetics, stress or genetics. Aim: Understanding of the relationship between hormonal contraceptives and hyperpigmentation. Material and Methods: A bibliographic review through a research in diverse databases (PubMed, Google Scholar, ScienceDirect and Wiley Online Library). Results/Discussion: According to some authors, estrogenic components found in hormonal contraceptives are associated with hyperpigmentation situations. In the case of progestagenic components, opinions diverge: some studies substantiate that progesterone has the ability to increase melanogenesis and others that it may have the opposite effect of estrogen. In a general way, most researchers say that hormonal contraceptives affect melanin synthesis; however others reject that fact. Conclusion: It is verified the relationship between hormonal contraceptives and hyperpigmentation. However, this topic is not sufficiently well approached, so future investigations are needed to allow its best understanding.info:eu-repo/semantics/publishedVersio

    Atomic detection in microwave cavity experiments: a dynamical model

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    We construct a model for the detection of one atom maser in the context of cavity Quantum Electrodynamics (QED) used to study coherence properties of superpositions of electromagnetic modes. Analytic expressions for the atomic ionization are obtained, considering the imperfections of the measurement process due to the probabilistic nature of the interactions between the ionization field and the atoms. Limited efficiency and false counting rates are considered in a dynamical context, and consequent results on the information about the state of the cavity modes are obtained.Comment: 12 pages, 1 figur

    Control of state and state entanglement with a single auxiliary subsystem

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    We present a strategy to control the evolution of a quantum system. The novel aspect of this protocol is the use of a \emph{single auxiliary subsystem}. Two applications are given, one which allows for state preservation and another which controls the degree of entanglement of a given initial state

    Urachal Tumor: A Case Report of an Extremely Rare Carcinoma

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    The urachus is a tubular structure that connects the bladder to the allantois in the embryonic development, involuting after the third trimester. The urachus carcinoma is an extremely rare tumor that accounts for <1% of all bladder cancers. We report a case of a 46-year-old woman, with no past medical history, complaining of hematuria with 6-month duration and a physical exam and an abdominal computed topographic scan revealing an exophytic mass of 6.8 cm longer axis that grew depending on the anterior bladder wall, invading the anterior abdominal wall. Cystoscopy detected mucosal erosion. The biopsy showed structures of adenocarcinoma of enteric type. The surgical specimen showed urachus adenocarcinoma of enteric type with stage IVA in the Sheldon system and stage III in the Mayo system. This case has a 3-year follow-up without disease recurrence.info:eu-repo/semantics/publishedVersio

    Biofilm growth and hydrodynamic behaviour in the biological plate tower (BPT) with and without hanging biomass (BPT-HB)

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    Deodorization and volatile organic compound abatement from polluted air streams can be accomplished with the biological plate tower (BPT), which has proved to be a reliable alternative to biofilters and biotrickling filters. Unlike those, the BPT is a non-clogging device, with constant active surface, and steady performance, making it ideal for scale-up and modelling. The initial BPT design needed improvement for better performance. The cylindrical body (circular plates) was replaced by a rectangular cuboid (rectangular plates). Holes in the plates did augment the amount of active biomass (hanging from the holes and under the plates), without reducing the transfer of toluene from the gaseous to the liquid phase. The diminished distance between plates was well tolerated in cocurrent flow, allowing much higher quantities of biomass in the same reactor volume. With 18 and 14 mm spacing between adjacent plates, the BPT, with and without holes, was tested for flooding, holdup and pressure drop. Several gas and liquid flows were tested, both in co-current and countercurrent. In hydrodynamic terms, the BPT-HB with co-current flow was clearly the best option. Higher stability with higher flow rates, and lower pressure drops were observed. The inoculum was obtained from wastewater plant activated sludge (petrochemical industry)

    Network of recurrent events for the Olami-Feder-Christensen model

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    We numerically study the dynamics of a discrete spring-block model introduced by Olami, Feder and Christensen (OFC) to mimic earthquakes and investigate to which extent this simple model is able to reproduce the observed spatiotemporal clustering of seismicty. Following a recently proposed method to characterize such clustering by networks of recurrent events [Geophys. Res. Lett. {\bf 33}, L1304, 2006], we find that for synthetic catalogs generated by the OFC model these networks have many non-trivial statistical properties. This includes characteristic degree distributions -- very similar to what has been observed for real seismicity. There are, however, also significant differences between the OFC model and earthquake catalogs indicating that this simple model is insufficient to account for certain aspects of the spatiotemporal clustering of seismicity.Comment: 11 pages, 16 figure
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