نوشته شده توسط : bernarducci

AbstractWe consider the time evolution of a dynamic quantum system coupled to a repeatedly measured ancilla. Given the time lapse Δt between two subsequent measurements, the combined system may be described using a difference master equation whereas, in the Zeno-limit Δt → 0, the evolution of the dynamic system is unitary and defined by the state of the ancilla. For an arbitrary Δt, we also formulate a master equation that interpolates smoothly the exact evolution given by the difference equation.In the special case of a nondemolition interaction Hamiltonian, the master equation of the total system reduces to uncoupled systems of first order differential equations, whose dimensions are the same as the dimension Na of the ancilla Hilbert space.


After having traced over the ancilla state,the master equation of the dynamic system can be expressed either as Nath order differential equations in time or, equivalently, as Zwanzig equations with an explicit memory over the system evolution.The above results are applied to a harmonic oscillator coupled to a two-level system, that serves as the repeatedly measured ancilla. Relatively sparse measurements are shown to destroy the coherence of the oscillator whereas, in the Zeno-limit, the coherence is preserved for all times. This is demonstrated by a periodic generation of a Schr? dinger cat-like state. The decoherence process is highly nonlinear in the initial state amplitude and the decoherence time decreases rapidly for increasing amplitude.



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تاریخ انتشار : شنبه 18 مهر 1394 | نظرات ()
نوشته شده توسط : bernarducci

Intramolecular electron transfer (IET) between the molybdenum and heme centers of vertebrate sulfite oxidase (SO) is proposed to be a key step in the catalytic cycle of the enzyme. However, the X-ray crystallographic distance between these centers, R(MoFe) = 32.3 Å, appears to be too long Nike Running Trainers Sale Uk for the rapid IET rates observed in liquid solution.

The Mo and heme domains are linked by a flexible tether, and it has been proposed that Roshe Run Uk Cheap dynamic interdomain motion brings the two metal centers closer together and thereby facilitates rapid IET. To date, there have been no direct distance measurements for SO in solution that would support or contradict this model.

In this work, pulsed electron-electron double resonance (ELDOR) and relaxation induced dipolar modulation enhancement (RIDME) techniques Nike Free Sale were... used to obtain information about R(MoFe) in the Mo(V)Fe(III) state of Air Max 87 wild type recombinant human SO in frozen glassy solution. Surprisingly, the data obtained suggest a fixed structure with R(MoFe) = 32 Å, similar to that determined by X-ray crystallography for chicken SO, although the orientation of the R(MoFe) radius-vector with respect to the heme center was found to be somewhat different. The implications of these findings for the flexible tether model are discussed.



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تاریخ انتشار : سه شنبه 6 مرداد 1394 | نظرات ()
نوشته شده توسط : bernarducci

Altogether data from 820 patients and 2335 control subjects corresponding to 85% of eligible patients and 76% of eligible control subjects were analysed. Questions focused on perinatal events and early eating habits including vitamin D supplementation. The frequency of vitamin D supplementation in different countries varied from 47 to 97% among control subjects.Field cases of EDSV in wild and domestic ducks were investigated. Six cases from domestic Pekin ducks were identified by PCR detection and were used for virus isolation and molecular analysis. Phylogenetic analyses of the partial hexon and full fiber genes showed that the D11-JW-012 and D11-JW-017 strains among 6 isolates belonged to different clusters compared with other known strains including the 127 strain.

Major nuclear accidents, such as the recent accident in Fukushima, Japan, have been shown to decrease the public's acceptance of nuclear power. However, little is known about how a serious accident affects people's acceptance of nuclear power and the determinants of acceptance. We conducted a longitudinal study (N= 790) in Switzerland: one survey was done five months before and one blue light blocking glasses directly after the accident in Fukushima.Comments on Shrank et al., focus group findings about the influence of culture on communication preferences in end-of-life care.Perkins HS, De Souza EP, Cortez JD, Hazuda HP. J Gen Intern Med. 2006 Apr; 21(4):399-400. Lipoma is the most frequently occurring benign soft tissue tumor in the shoulder and the axillary region in middle-aged and older persons, yet few such lipoma cases have been associated with clinical symptoms. A 38-year-old right-handed man presented with an enlarged feeling and a painful back-and-forth popping in his left shoulder. Although moderate tenderness of the subacromial bursa and bicipital groove existed, an obvious impingement sign was absent.

An initial limited search of MEDLINE and CINAHL databases was undertaken followed by an analysis of the text words contained in the title and abstract to identify the optimal index terms. A second extensive search using all identified key words and index terms was then undertaken. Third, the reference list and bibliographies of all identified reports and articles were searched for additional studies.Bats were able to contact the sap when the skirt did not entirely cover the sap producing surface. Therefore, in 2010 we requested the sap harvesters to use larger skirts. During 2010 bats contacted date blue light blocking reading glasses palm sap [2% vs. The hypothesis tested was that most pupae of Aedes aegypti are produced in a few types of containers so that vector control efforts could concentrate on eliminating the most productive ones and thus prevent dengue outbreaks. Pupal surveys were conducted twice in 2004 in an urban area in southern Puerto Rico. A total 35,030 immature mosquitoes (III and IV instars, pupae) was counted in 1,367 containers found with water in 624 premises during the first survey.



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تاریخ انتشار : پنج شنبه 10 ارديبهشت 1394 | نظرات ()
نوشته شده توسط : bernarducci

Elegans embryo. Here we show that blocking engulfment enhances cell survival when cells are subjected to weak pro-apoptotic signals. Thus, genes that mediate corpse removal can also function to actively kill cells.Comment inApoptosis. In aquatic birds, especially in migrating Anatidae, these larvae reach the visceral vessels, become adults in a few weeks, lay eggs, then degenerate. Corresponding miracidia contaminate new limneids. Since 1993, the total number of annual cases of cercarial dermatitis has increased from only ten to thousands in France and the affection rages in pools where limneids, migrating water birds and swimmers gather together.

Left ventricular biopsies were collected at 5min following institution of cardiopulmonary bypass, 30min after cross-clamping the aorta and 20min after cross-clamp removal, and used to determine metabolic changes during surgery. Metabolites (adenine nucleotides, amino acids and lactate) were measured using high pressure liquid chromatography and enzymatic techniques. Postoperative myocardial troponin I release was used as a marker of myocardial injury.RESULTS: Ischaemic arrest was associated with significant increase in lactate and alanine/glutamate ratio only in the warm blood group. STUDY OBJECTIVE: We evaluate the safety and efficacy of a pain protocol using 1 mg intravenous (IV) hydromorphone followed by an optional dose of 1 mg IV hydromorphone 15 minutes later.METHODS: Prospective interventional study at an urban academic emergency department (ED). One milligram of IV hydromorphone was administered to adults 21 to 64 years of age who had acute severe pain. Fifteen minutes later, patients were asked whether they wanted more pain medication.

Nurse teachers can often find themselves in various situations where they resort to using humour. An exploration of the role of humour within the educational relationship between nurse teachers and nursing students is the focus of this paper. Consideration is given to the nurse teachers' requirement to develop self-awareness in their own understanding of humour in order to facilitate and recognize the reasons for the nursing students' use of humour. BACKGROUND: Four-corner fusion of the wrist is an option for management of non-union scaphoid with painful arthritis of the wrist. Various surgical techniques have been devised for four-corner fusion, with inconsistent results. We present our experience of four-corner fusion achieved using a standard H-plate, designed originally for anterior cervical plating.MATERIALS AND METHODS: The study is a retrospective analysis of six cases of painful wrist arthritis resulting from nonunion of scaphoid treated by four-corner fusion, between 1996 and 2004.



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تاریخ انتشار : چهار شنبه 9 ارديبهشت 1394 | نظرات ()

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