9,618 research outputs found

    Phonon arithmetic in a trapped ion system

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    Single-quantum level operations are important tools to manipulate a quantum state. Annihilation or creation of single particles translates a quantum state to another by adding or subtracting a particle, depending on how many are already in the given state. The operations are probabilistic and the success rate has yet been low in their experimental realization. Here we experimentally demonstrate (near) deterministic addition and subtraction of a bosonic particle, in particular a phonon of ionic motion in a harmonic potential. We realize the operations by coupling phonons to an auxiliary two-level system and applying transitionless adiabatic passage. We show handy repetition of the operations on various initial states and demonstrate by the reconstruction of the density matrices that the operations preserve coherences. We observe the transformation of a classical state to a highly non-classical one and a Gaussian state to a non-Gaussian one by applying a sequence of operations deterministically

    Entanglement versus mutual information in quantum spin chains

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    The quantum entanglement EE of a bipartite quantum Ising chain is compared with the mutual information II between the two parts after a local measurement of the classical spin configuration. As the model is conformally invariant, the entanglement measured in its ground state at the critical point is known to obey a certain scaling form. Surprisingly, the mutual information of classical spin configurations is found to obey the same scaling form, although with a different prefactor. Moreover, we find that mutual information and the entanglement obey the inequality IEI\leq E in the ground state as well as in a dynamically evolving situation. This inequality holds for general bipartite systems in a pure state and can be proven using similar techniques as for Holevo's bound.Comment: 10 pages, 3 figure

    Transient limb ischemia induces remote ischemic preconditioning in vivo

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    Background-Ischemic preconditioning reduces local tissue injury caused by subsequent ischemia-reperfusion (IR), but may also have a salutary effect on IR injury of tissues remote from those undergoing preconditioning. We tested the hypothesis that limb ischemia induces remote preconditioning, reduces endothelial IR injury in humans, and reduces experimental myocardial infarct size.Methods and Results-Endothelial IR injury of the human forearm was induced by 20 minutes of upper limb ischemia (inflation of a blood pressure cuff to 200 mm Hg) followed by reperfusion. Remote preconditioning was induced by three 5-minute cycles of ischemia of the contralateral limb. Venous occlusion plethysmography was used to assess forearm blood flow in response to acetylcholine at baseline and 15 minutes after reperfusion. Experimental myocardial infarction was achieved by 40 minutes of balloon occlusion of the left anterior descending artery in 15-kg pigs. Remote preconditioning was induced by four 5-minute cycles of lower limb ischemia. Triphenyltetrazolium staining was used to assess the extent of myocardial infarction. In the human study, the response to acetylcholine was significantly attenuated in the control group after 15 minutes' reperfusion, but remote preconditioning prevented this reduction. Limb ischemia caused a significant reduction in the extent of myocardial infarction relative to the area at risk compared with control (26 +/- 9% versus 53 +/- 8%, P < 0.05).Conclusion-Remote ischemic preconditioning prevents IR-induced endothelial dysfunction in humans and reduces the extent of myocardial infarction in experimental animals. Transient limb ischemia is a simple preconditioning stimulus with important potential clinical applications

    Ectopia cordis : a report of two cases in Cameroon

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    This article reports two cases of ectopia cordis in two children aged one day and twenty months respectively. A one day old newborn had complete thoracic ectopia cordis associated with an internal cardiac defect and severe thoracic and abdominal wall malformations. The centre does not have the facilities to manage complex congenital defects and prior to being transferred to a cardiac centre, the neonate died on the second day of admission. A 20-month old baby had partial ectopia of the heart and a defect in the abdominal wall. He had no major congenital cardiac defect and has remained clinically stable with no life threatening symptomspeer-reviewe

    Superconductivity-induced Phonon Renormalization on NaFe1x_{1-x}Cox_{x}As

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    We report a study of the lattice dynamics in superconducting NaFeAs (Tc = 8 K) and doped NaFe0.97Co0.03As (Tc = 20 K) using Raman light scattering. Five of the six phonon modes expected from group theory are observed. In contrast with results obtained on iso-structural and iso-electronic LiFeAs, anomalous broadening of Eg(As) and A1g(Na) modes upon cooling is observed in both samples. In addition, in the Co-doped sample, a superconductivity-induced renormalization of the frequency and linewidth of the B1g(Fe) vibration is observed. This renormalization can not be understood within a single band and simple multi-band approaches. A theoretical model that includes the effects of SDW correlations along with sign-changing s-wave pairing state and interband scattering has been developed to explain the observed behavior of the B1g(Fe) mode.Comment: 10 pages; 6 figure

    Investigating the association of rs2910164 with cancer predisposition in an Irish cohort.

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    IntroductionMicroRNAs (miRNAs) are small noncoding RNA molecules that exert post-transcriptional effects on gene expression by binding with cis-regulatory regions in target messenger RNA (mRNA). Polymorphisms in genes encoding miRNAs or in miRNA-mRNA binding sites confer deleterious epigenetic effects on cancer risk. miR-146a has a role in inflammation and may have a role as a tumour suppressor. The polymorphism rs2910164 in the MIR146A gene encoding pre-miR-146a has been implicated in several inflammatory pathologies, including cancers of the breast and thyroid, although evidence for the associations has been conflicting in different populations. We aimed to further investigate the association of this variant with these two cancers in an Irish cohort.MethodsThe study group comprised patients with breast cancer (BC), patients with differentiated thyroid cancer (DTC) and unaffected controls. Germline DNA was extracted from blood or from saliva collected using the DNA Genotek Oragene 575 collection kit, using crystallisation precipitation, and genotyped using TaqMan-based PCR. Data were analysed using SPSS, v22.ResultsThe total study group included 1516 participants. This comprised 1386 Irish participants; 724 unaffected individuals (controls), 523 patients with breast cancer (BC), 136 patients with differentiated thyroid cancer (DTC) and three patients with dual primary breast and thyroid cancer. An additional cohort of 130 patients with DTC from the South of France was also genotyped for the variant. The variant was detected with a minor allele frequency (MAF) of 0.19 in controls, 0.22 in BC and 0.27 and 0.26 in DTC cases from Ireland and France, respectively. The variant was not significantly associated with BC (per allele odds ratio = 1.20 (0.98-1.46), P  = 0.07), but was associated with DTC in Irish patients (per allele OR = 1.59 (1.18-2.14), P = 0.002).ConclusionThe rs2910164 variant in MIR146A is significantly associated with DTC, but is not significantly associated with BC in this cohort

    Quantum state conversion by cross-Kerr interaction

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    A generalized Mach-Zehnder-type interferometer equipped with cross-Kerr elements is proposed to convert N-photon truncated single-mode quantum states into (N+1)-mode single-photon states, which are suitable for further state manipulation by means of beam splitter arrays and ON/OFF-detections, and vice versa. Applications to the realization of unitary and non-unitary transformations, quantum state reconstruction, and quantum telemanipulation are studied.Comment: 22 pages, 4 figures, using a4.st

    Carotid artery stenting with contralateral carotid occlusion in a rare aortic arch configuration

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    We present the case of a 47-year-old man admitted to our department with an episode of aphasia. Duplex scan showed an occluded right internal carotid artery and severe left internal carotid artery stenosis. Contrast-enhanced computer tomography demonstrated a common trunk for both common carotid arteries anterior to the trachea and aberrant right subclavian artery posterior to the esophagus. The patient was considered to be a high risk for carotid endarterectomy and, consequently, we performed stenting of the left carotid artery. To our knowledge, this is the first case reporting the combination of these two aortic arch anomalies and the concomitant endovascular treatment of atherosclerotic carotid stenosis

    Studi Perbandingan Back Propogation

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    Keberhasilan pemahaman tentang bagaimana membuat komputer belajar akan membuka banyak manfaat baru dari komputer. Sebuah pemahaman yang rinci tentang algoritma pengolahan informasi untuk pembelajaran mesin dapat membuat pemahaman yang sebaik kemampuan belajar manusia. Banyak jenis pembelajaran mesin yang kita tahu, beberapa diantaranya adalah Backpropagation (BP), Extreme Learning Machine (ELM), dan Support Vector Machine (SVM). Penelitian ini menggunakan lima data yang memiliki beberapa karakteristik. Hasil penelitian ini, dari ketiga model yang diamati memberikan akurasi klasifikasi yang sebanding. Penelitian ini memiliki tiga kesimpulan, yang terbaik dalam akurasi adalah BP, yang terbaik dalam stabilitas adalah SVM dan CPU time terbaik adalah ELM untuk data bioinformatika

    Endograft connector technique to treat popliteal artery aneurysm in a morbid obese patient.

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    Surgical repair of popliteal artery aneurysm in morbid obese patients poses additional challenges. We report a morbid obese patient who had a 59mm right popliteal artery aneurysm which was successfully treated with the endograft connector technique. This technique was used to perform the distal anastomosis of the below-knee femoro-popliteal bypass. A 10mm Dacron graft was used as a main graft bypass and an 11 mm/10 cm stentgraft as endograft connector. Following the respective tunnel of the Dacron graft, an end-to-side proximal anastomosis was performed at distal femoral artery. The aneurysm exclusion was obtained through a proximal and a distal ligation. Postoperative duplex showed adequate bypass patency. Knee x-rays demonstrated no signs of stent kinking/fractures. The postoperative course was uneventful and the patient was discharged home on fourth day post operative. The six-month computed tomography scan and the 12-month duplex control showed a patent bypass with no signs of stenosis
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