887 research outputs found

    Charge-to-spin conversion of electron entanglement states and spin-interaction-free solid-state quantum computation

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    Without resorting to spin-spin coupling, we propose a scalable spin quantum computing scheme assisted with a semiconductor multiple-quantum-dot structure. The techniques of single electron transitions and the nanostructure of quantum-dot cellular automata (QCA) are used to generate charge entangled states of two electrons, which are then converted into spin entanglement states using single-spin rotations only. Deterministic two-qubit quantum gates are also manipulated using only single-spin rotations with the help of QCA. A single-shot readout of spin states can be carried out by coupling the multiple dot structure to a quantum point contact. As a result, deterministic spin-interaction-free quantum computing can be implemented in semiconductor nanostructure.Comment: 5 pages, 4 figures, the revised version of quant-ph/0502002 for publication in Phys. Rev. B (to be appear on the issue of Oct. 15, 2007

    Quantitative Test of SO(5) Symmetry in the Vortex State of Nd1.85Ce0.15CuO4Nd_{1.85}Ce_{0.15}CuO_4

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    By numerically solving models with competing superconducting and antiferromagnetic orders, we study the magnetic field dependence of the antiferromagnetic moment in both the weak and strong field regimes. Through a omparison with the neutron scattering results of Kang et al and Matsuura et al.on Nd1.85Ce0.15CuO4Nd_{1.85}Ce_{0.15}CuO_4, we conclude that this system is close to a SO(5) symmetric critical point. We also make a quantitative prediction on increasing the upper critical field Bc2B_{c2} and the superconducting transition temperature TcT_c by applying an in-plane magnetic field.Comment: 4 pages, 3 figures v3: final version PRL 92, 107002 (2004

    Spin correlations in the electron-doped high-transition-temperature superconductor Nd{2-x}Ce{x}CuO{4+/-delta}

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    High-transition-temperature (high-Tc) superconductivity develops near antiferromagnetic phases, and it is possible that magnetic excitations contribute to the superconducting pairing mechanism. To assess the role of antiferromagnetism, it is essential to understand the doping and temperature dependence of the two-dimensional antiferromagnetic spin correlations. The phase diagram is asymmetric with respect to electron and hole doping, and for the comparatively less-studied electron-doped materials, the antiferromagnetic phase extends much further with doping [1, 2] and appears to overlap with the superconducting phase. The archetypical electron-doped compound Nd{2-x}Ce{x}CuO{4\pm\delta} (NCCO) shows bulk superconductivity above x \approx 0.13 [3, 4], while evidence for antiferromagnetic order has been found up to x \approx 0.17 [2, 5, 6]. Here we report inelastic magnetic neutron-scattering measurements that point to the distinct possibility that genuine long-range antiferromagnetism and superconductivity do not coexist. The data reveal a magnetic quantum critical point where superconductivity first appears, consistent with an exotic quantum phase transition between the two phases [7]. We also demonstrate that the pseudogap phenomenon in the electron-doped materials, which is associated with pronounced charge anomalies [8-11], arises from a build-up of spin correlations, in agreement with recent theoretical proposals [12, 13].Comment: 5 pages, 4 figure

    Fine structure of alpha decay in odd nuclei

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    Using an alpha decay level scheme, an explanation for the fine structure in odd nuclei is evidenced by taking into account the radial and rotational couplings between the unpaired nucleon and the core of the decaying system. It is stated that the experimental behavior of the alpha decay fine structure phenomenon is directed by the dynamical characteristics of the system.Comment: 8 pages, 3 figures, REVTex, submitted to Physical Review

    Successful strategies implemented towards the elimination of canine rabies in the Western Hemisphere

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    Almost all cases of human rabies result from dog bites, making the elimination of canine rabies a global priority. During recent decades, many countries in the Western Hemisphere have carried out large-scale dog vaccination campaigns, controlled their free-ranging dog populations and enforced legislation for responsible pet ownership. This article reviews progress in eliminating canine rabies from the Western Hemisphere. After briefly summarizing the history of control efforts and describing the approaches listed above, we note that programs in some countries have been hindered by societal attitudes and severe economic disparities, which underlines the need to discuss measures that will be required to complete the elimination of canine rabies throughout the region. We also note that there is a constant threat for dog-maintained epizootics to re-occur, so as long as dog-maintained rabies "hot spots" are still present, free-roaming dog populations remain large, herd immunity becomes low and dog-derived rabies lyssavirus (RABLV) variants continue to circulate in close proximity to rabies-naïve dog populations. The elimination of dog-maintained rabies will be only feasible if both dog-maintained and dog-derived RABLV lineages and variants are permanently eliminated. This may be possible by keeping dog herd immunity above 70% at all times, fostering sustained laboratory-based surveillance through reliable rabies diagnosis and RABLV genetic typing in dogs, domestic animals and wildlife, as well as continuing to educate the population on the risk of rabies transmission, prevention and responsible pet ownership. Complete elimination of canine rabies requires permanent funding, with governments and people committed to make it a reality. An accompanying article reviews the history and epidemiology of canine rabies in the Western Hemisphere, beginning with its introduction during the period of European colonization, and discusses how spillovers of viruses between dogs and various wild carnivores will affect future eradication efforts (Velasco-Villa et al., 2017)

    LYCOPENE AND THE ROLE IN METABOLIC PREVENTION

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    The origin of the tomato plant seems to be South America, in particular Chile and Ecuador, where it grows as a wild plant due to the tropical climate and is able to bear fruit throughout the year, while in European regions, if cultivated in 'open, has a seasonal cycle limited to the summer period. From here, it later spread to Central America and it was the Spaniards who made it known in Europe in the 16th century. Only at the end of the 18th century, the cultivation of tomatoes for food purposes experienced a strong boost in Europe, mainly in France and Southern Italy. Starting from the 19th century, the tomato was finally included in European gastronomic treaties, favoring a conspicuous diffusion both on the tables of the richest and those of the less well-off. Today tomatoes are a staple of our diet a series of researches have identified the effects that the consumption of this particular food, in its many variations, has on our health. If previously the effects that tomatoes have on the improvement of blood lipids were recognized, now researchers have identified a direct correlation between the risk of cardiovascular mortality and the consumption of the fruit, for the presence of Lycopene, a carotenoid antioxidant. It is lycopene, in particular, that produces the greatest benefits for our body. It is a powerful antioxidant that determines, among other things, the particular red color of the tomato. Through research on the effects of a diet rich in tomatoes on the body, the experts found a progressive decrease in the concentration of cholesterol accompanied by a decrease in cardiovascular risk

    HEALTH PROPERTIES OF LYCOPERSICUM ESCULENTUM

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    The tomato, Lycopersicum esculentum, is a horticultural plant belonging to the Solanaceae family. In Italy, the term "tomato" is found for the first time in the famous "Herbarius" by Pietro Mattioli. The etymology of the name leads back to the Latin "pomum aureus", apple or golden apple. Unlike in other languages, such as English, the term "tomato" is linked to the etymology of the Aztec version "Xitotomate". The origin of the tomato plant seems to be South America, in particular Chile and Ecuador, where it grows as a wild plant due to the tropical climate and is able to bear fruit throughout the year, while in European regions, if cultivated in 'open, has a seasonal cycle limited to the summer period. From here, it later spread to Central America and it was the Spaniards who made it known in Europe in the 16th century. The cultivation of the tomato plant was already widespread in the pre-Columbian age, when it was used as an ornamental plant and was not used in the kitchen: this is because the tomato was considered poisonous due to its high content in solanine, a substance considered harmful for the 'man. In 1544, the Italian herbalist Pietro Mattioli classified the tomato plant among the poisonous species. It is not clear when the tomato, as an ornamental and poisonous plant, was considered edible by Europeans; it should be noted that not even the inhabitants of South America ate the fruits of the plant. From Europe, or perhaps more precisely from Spain, the tomato plant landed in Morocco, where it found an ideal climate, and from there it spread throughout the Mediterranean basin. Starting from the seventeenth century, in southern Europe, as well as in Bohemia and England, the tomato began to be used fresh and for the preparation of sauces, while its diffusion as a food in northern Europe encountered many difficulties, perhaps due to the presence of other similar wild plants which, due to their high alkaloid content, were not suitable for food consumption. Only at the end of the 18th century, the cultivation of tomatoes for food purposes experienced a strong boost in Europe, mainly in France and Southern Italy. Starting from the 19th century, the tomato was finally included in European gastronomic treaties, favoring a conspicuous diffusion both on the tables of the richest and those of the less well-off

    Wholegenome analysis suggesting probiotic potential and safety properties of Pediococcus pentosaceus DSPZPP1, a promising LAB strain isolated from traditional fermented sausages of the Basilicata region (Southern Italy).

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    Introduction: Many lactic acid bacteria (LAB) strains are currently gaining attention in the food industry and various biological applications because of their harmless and functional properties. Given the growing consumer demand for safe food, further research into potential probiotic bacteria is beneficial. Therefore, we aimed to characterize Pediococcus pentosaceus DSPZPP1, a LAB strain isolated from traditional fermented sausages from the Basilicata region of Southern Italy. Methods: In this study, we analyzed the whole genome of the P. pentosaceus DSPZPP1 strain and performed in silico characterization to evaluate its applicability for probiotics and use in the food industry. Results and Discussion: The whole-genome assembly and functional annotations revealed many interesting characteristics of the DSPZPP1 strain. Sequencing raw reads were assembled into a draft genome of size 1,891,398 bp, with a G + C content of 37.3%. Functional annotation identified 1930 proteinencoding genes and 58 RNAs including tRNA, tmRNA, and 16S, 23S, and 5S rRNAs. The analysis shows the presence of genes that encode water-soluble B-group vitamins such as biotin, folate, coenzyme A, and riboflavin. Furthermore, the analysis revealed that the DSPZPP1 strain can synthesize class II bacteriocin, penocin A, adding importance to the food industry for bio-enriched food. The DSPZPP1 genome does not show the presence of plasmids, and no genes associated with antimicrobial resistance and virulence were found. In addition, two intact bacteriophages were identified. Importantly, the lowest probability value in pathogenicity analysis indicates that this strain is non-pathogenic to humans. 16 s rRNA-based phylogenetic analysis and comparative analysis based on ANI and Tetra reveal that the DSPZPP1 strain shares the closest evolutionary relationship with P. pentosaceus DSM 20336 and other Pediococcus strains. Analysis of carbohydrate active enzymes (CAZymes) identified glycosyl transferases (GT) as a main class of enzymes followed by glycoside hydrolases (GH). Our study shows several interesting characteristics of the isolated DSPZPP1 strain from fermented Italian sausages, suggesting its potential use as a promising probiotic candidate and making it more appropriate for selection as a future additive in biopreservation
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