On-demand semiconductor single-photon source with near-unity indistinguishability

Single photon sources based on semiconductor quantum dots offer distinct advantages for quantum information, including a scalable solid-state platform, ultrabrightness, and interconnectivity with matter qubits. A key prerequisite for their use in optical quantum computing and solid-state networks is a high level of efficiency and indistinguishability. Pulsed resonance fluorescence (RF) has been anticipated as the optimum condition for the deterministic generation of high-quality photons with vanishing effects of dephasing. Here, we generate pulsed RF single photons on demand from a single, microcavity-embedded quantum dot under s-shell excitation with 3-ps laser pulses. The pi-pulse excited RF photons have less than 0.3% background contributions and a vanishing two-photon emission probability. Non-postselective Hong-Ou-Mandel interference between two successively emitted photons is observed with a visibility of 0.97(2), comparable to trapped atoms and ions. Two single photons are further used to implement a high-fidelity quantum controlled-NOT gate.Comment: 11 pages, 11 figure

Growth Performance and Root Transcriptome Remodeling of Arabidopsis in Response to Mars-Like Levels of Magnesium Sulfate

Martian regolith (unconsolidated surface material) is a potential medium for plant growth in bioregenerative life support systems during manned missions on Mars. However, hydrated magnesium sulfate mineral levels in the regolith of Mars can reach as high as 10 wt%, and would be expected to be highly inhibitory to plant growth. at 180 min. after initiation of treatment. mutants exhibit partial tolerance to magnesium sulfate, and by elucidating a small subset (500 vs. >10,000) of candidate genes for mutation or metabolic engineering that will enhance tolerance to magnesium sulfate soils

High-level classification of the Fungi and a tool for evolutionary ecological analyses

High-throughput sequencing studies generate vast amounts of taxonomic data. Evolutionary ecological hypotheses of the recovered taxa and Species Hypotheses are difficult to test due to problems with alignments and the lack of a phylogenetic backbone. We propose an updated phylum-and class-level fungal classification accounting for monophyly and divergence time so that the main taxonomic ranks are more informative. Based on phylogenies and divergence time estimates, we adopt phylum rank to Aphelidiomycota, Basidiobolomycota, Calcarisporiellomycota, Glomeromycota, Entomophthoromycota, Entorrhizomycota, Kickxellomycota, Monoblepharomycota, Mortierellomycota and Olpidiomycota. We accept nine subkingdoms to accommodate these 18 phyla. We consider the kingdom Nucleariae (phyla Nuclearida and Fonticulida) as a sister group to the Fungi. We also introduce a perl script and a newick-formatted classification backbone for assigning Species Hypotheses into a hierarchical taxonomic framework, using this or any other classification system. We provide an example of testing evolutionary ecological hypotheses based on a global soil fungal data set.Peer reviewe

Prevention of acute kidney injury and protection of renal function in the intensive care unit

Acute renal failure on the intensive care unit is associated with significant mortality and morbidity. To determine recommendations for the prevention of acute kidney injury (AKI), focusing on the role of potential preventative maneuvers including volume expansion, diuretics, use of inotropes, vasopressors/vasodilators, hormonal interventions, nutrition, and extracorporeal techniques. A systematic search of the literature was performed for studies using these potential protective agents in adult patients at risk for acute renal failure/kidney injury between 1966 and 2009. The following clinical conditions were considered: major surgery, critical illness, sepsis, shock, and use of potentially nephrotoxic drugs and radiocontrast media. Where possible the following endpoints were extracted: creatinine clearance, glomerular filtration rate, increase in serum creatinine, urine output, and markers of tubular injury. Clinical endpoints included the need for renal replacement therapy, length of stay, and mortality. Studies are graded according to the international Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) group system Several measures are recommended, though none carries grade 1A. We recommend prompt resuscitation of the circulation with special attention to providing adequate hydration whilst avoiding high-molecular-weight hydroxy-ethyl starch (HES) preparations, maintaining adequate blood pressure using vasopressors in vasodilatory shock. We suggest using vasopressors in vasodilatory hypotension, specific vasodilators under strict hemodynamic control, sodium bicarbonate for emergency procedures administering contrast media, and periprocedural hemofiltration in severe chronic renal insufficiency undergoing coronary intervention

Využití tixoformingu jako metody výroby kovových kompozitů

Tixoforming patří do skupiny procesů využívající semi-solid zpracování. Touto metodou je možné získat díly s komplexním tvarem a díky svým tixotropním vlastnostem lze dosáhnout nekonvenčních mikrostruktur. V této studii však byl tixoforming použit jak jako způsob tváření, tak i způsob výroby. Kovové kompozity byly vyrobeny procesem integrace práškové metalurgie a techniky výroby polotuhých látek. Směs slitiny Co72.5B15Si12.5 a Fe se částečně roztaví, mechanicky stlačí v polotuhém stavu a vyplní tvarovou dutiny formy. Bez změny struktury slitiny by bylo možné jí zpevnit využitím prášku Fe. Kromě toho bylo možno současně dosáhnout i konečného tvaru produktu. Před procesem byla slitina Co72.5B15Si12.5 ve formě tyčinky charakterizována rentgenovou difrakcí (XRD), skenovací elektronovou mikroskopií - energetickou disperzní spektroskopií (SEM – EDX), diferenční termickou analýzou - termogravimetrií (DTA-TG) ), světelnou mikroskopií a měřením mikrotvrdosti. Tyčinka byla namleta, aby byl získán prášek, který byl následně smíchán s práškem Fe. Po tváření byla provedena charakterizace struktur kompozitního materiálu. Bylo zjištěno, že proces zpracování vede k získání kompletních kompozitů s kovovou matricí.Thixoforming is one of the members of the family of semi-solid forming processes. It is possible to obtain complex shape of materials by this method and unconventional microstructures can be achieved due to its thixotropic properties. However, in this study thixoforming was used not only as forming method but also as a manufacturing method. Metallic composites were manufactured by a process of integration of powder metallurgy and semi-solid production technique. The mixture of Co72.5B15Si12.5 alloy and Fe powders become partially melted, compressed mechanically in semi-solid state and filled intricate cavities. Without changing alloy structure, it could be possible to reinforce it with Fe powders. Moreover, the final shape of the product could be achieved at the same time. Prior to the process, Co72.5B15Si12.5 alloy obtained in the form of stick was characterized by X-ray diffraction (XRD), scanning electron microscopy–energy dispersive spectroscopy (SEM–EDX), differential thermal analysis-thermogravimetry (DTA-TG), light microscope and micro-hardness machine. The stick was milled to get alloy powders and they were blended with iron. Characterization of the structures of the composite material was performed. It was concluded that the heating process of iron and alloy powders provides the formation of compact metal matrix composites

A case of mistaken identity

What went wrong between the UK media and a report on 'multi-ethnic' Britain