5,762 research outputs found

    Digital data reformatter/deserializer

    Get PDF
    A method and apparatus is presented for reformatting and de-serializing a serially-received sequence of data words, each consisting of a fixed number of binary data bits. A block of nm bits is serially fed into a shift register or serially-connected group of shift registers. In lieu of the(nm-1)th shifts, the bits are rearranged within the shift register in parallel fashion, according to a prescribed scheme. Shifting then continues, until the first bit of each data word appears in the last bit position in the shift register, at which time that data word is shifted in parallel into an output buffer stage, from which it is outputted in parallel, after a fixed delay

    Collectors of Rhodiola species on the Sichuan-Tibetan and Sichuan-Shaanxi borders

    Get PDF
    Medicinal Rhodiola species, including Rhodiola rosea L. and Rhodiola crenulata (Hook.f. & Thomson) H.Ohba, have been widely used as traditional herbal medicines with numerous claims for their therapeutic effects. Faced with resource depletion, environment destruction and higher demand, R. rosea and R. crenulata are becoming endangered, making them economically even more valuable, but also increasing the risk of adulteration and low quality - and raising awareness for the role of often unlicensed collectors and middlemen. Although R. rosea is the most well known in Europe, R. crenulata is the recognised species in China. On the border of Sichuan and Tibet, members of the Yi minority collect R. crenulata in order to sell it to the “traditional” Chinese medicine market. Collection of this medicinal herb represents about one third of the annual income for the Yi. Three times a year they climb up to 5,000 metres in search of the plants. As it is stripped out, the Yi have to travel to more and more inhospitable places to ensure its supply. At Taibai mountain along the border of Sichuan and Shaanxi, the same medicinal plant, hongjingtian in Chinese, is growing in the wild, too. Yet, in a socioeconomic context, collectors do not have a particular ethnic background such as Yi, Tibetan or Han collectors. Here, the collectors are various unlicensed providers-cum-prescribers 'caoyi'. (The term does not mean herb-physician, as one might assume from terms such as caoyao (herbals). It means unofficial or not following the scholarly standard.) Using neither an ethnic identity nor the general botanical terms in Latin, they claim Daoism and terroir of their mountain as a sign of good quality ‘Taibai hongjingtian’. There appears to be no strategy in place to protect the species across all those socioeconomic, ethnic and provincial boundaries, and without some intervention it is likely that R. crenulata will eventually become so rare that it can no longer be collected in the current quantities. This will have consequences both for the livelihoods of the Yi and of various Caoyi, and also for the conservation of R. Crenulata and it’s sustainability

    Local invariants of stabilizer codes

    Full text link
    In [Phys. Rev. A 58, 1833 (1998)] a family of polynomial invariants which separate the orbits of multi-qubit density operators ρ\rho under the action of the local unitary group was presented. We consider this family of invariants for the class of those ρ\rho which are the projection operators describing stabilizer codes and give a complete translation of these invariants into the binary framework in which stabilizer codes are usually described. Such an investigation of local invariants of quantum codes is of natural importance in quantum coding theory, since locally equivalent codes have the same error-correcting capabilities and local invariants are powerful tools to explore their structure. Moreover, the present result is relevant in the context of multipartite entanglement and the development of the measurement-based model of quantum computation known as the one-way quantum computer.Comment: 10 pages, 1 figure. Minor changes. Accepted in Phys. Rev.

    A unified approach on Springer fibers in the hook, two-row and two-column cases

    Full text link
    We consider the Springer fiber over a nilpotent endomorphism. Fix a Jordan basis and consider the standard torus relative to this. We deal with the problem to describe the flags fixed by the torus which belong to a given component of the Springer fiber. We solve the problem in the hook, two-row and two-column cases. We provide two main characterizations which are common to the three cases, and which involve dominance relations between Young diagrams and combinatorial algorithms. Then, for these three cases, we deduce topological properties of the components and their intersections.Comment: 42 page

    The eclipsing post-common envelope binary CSS21055: a white dwarf with a probable brown-dwarf companion

    Full text link
    We report photometric observations of the eclipsing close binary CSS21055 (SDSS J141126+200911) that strongly suggest that the companion to the carbon-oxygen white dwarf is a brown dwarf with a mass between 0.030 and 0.074 Msun. The measured orbital period is 121.73min and the totality of the eclipse lasts 125s. If confirmed, CSS21055 would be the first detached eclipsing WD+BD binary. Spectroscopy in the eclipse could provide information about the companion's evolutionary state and atmospheric structure.Comment: 6 pages, 5 figure

    Systematic Review – Final: Have arid land springs restoration projects been effective in restoring hydrology, geomorphology, and invertebrates and plant species composition comparable to natural springs with minimal anthropogenic disturbance?

    Get PDF
    The aim of this review is to examine the effectiveness of springs restoration projects in the southwestern United States in restoring hydrology, geomorphology, and plant and invertebrates species composition to condiitions comparable with natural springs with minimal anthropogenic disturbances

    Black holes admitting a Freudenthal dual

    Full text link
    The quantised charges x of four dimensional stringy black holes may be assigned to elements of an integral Freudenthal triple system whose automorphism group is the corresponding U-duality and whose U-invariant quartic norm Delta(x) determines the lowest order entropy. Here we introduce a Freudenthal duality x -> \tilde{x}, for which \tilde{\tilde{x}}=-x. Although distinct from U-duality it nevertheless leaves Delta(x) invariant. However, the requirement that \tilde{x} be integer restricts us to the subset of black holes for which Delta(x) is necessarily a perfect square. The issue of higher-order corrections remains open as some, but not all, of the discrete U-duality invariants are Freudenthal invariant. Similarly, the quantised charges A of five dimensional black holes and strings may be assigned to elements of an integral Jordan algebra, whose cubic norm N(A) determines the lowest order entropy. We introduce an analogous Jordan dual A*, with N(A) necessarily a perfect cube, for which A**=A and which leaves N(A) invariant. The two dualities are related by a 4D/5D lift.Comment: 32 pages revtex, 10 tables; minor corrections, references adde
    corecore