2,220 research outputs found

    'Genealogical misfortunes': Achille Mbembe's (re-)writing of postcolonial Africa

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    In his latest work, Sortir de la grande nuit, the Cameroonian social theorist, Achille Mbembe nuances his description of the ontological status of the postcolonial African subject, which he had theorized extensively in his best-known text, On the Postcolony, and at the same time exploits the conceptual resources of a number of Jean-Luc Nancy’s lexical innovations. This recent text is also a reprise of an earlier autobiographical essay, and the gesture of this ‘reinscription’ is critical to our understanding of Mbembe’s status as a contemporary ‘postcolonial thinker’, and the way in which he positions himself within a certain intellectual genealogy of postcolonial theory. Within this trajectory, I argue that we can read fruitfully his relationship to three influential figures: Jacques Derrida, Jean-Luc Nancy and Ruben Um Nyobè

    Spacetime-Efficient Low-Depth Quantum State Preparation with Applications

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    We propose a novel deterministic method for preparing arbitrary quantum states. When our protocol is compiled into CNOT and arbitrary single-qubit gates, it prepares an NN-dimensional state in depth O(log(N))O(\log(N)) and spacetime allocation (a metric that accounts for the fact that oftentimes some ancilla qubits need not be active for the entire circuit) O(N)O(N), which are both optimal. When compiled into the {H,S,T,CNOT}\{\mathrm{H,S,T,CNOT}\} gate set, we show that it requires asymptotically fewer quantum resources than previous methods. Specifically, it prepares an arbitrary state up to error ϵ\epsilon in depth O(log(N/ϵ))O(\log(N/\epsilon)) and spacetime allocation O(Nlog(log(N)/ϵ))O(N\log(\log(N)/\epsilon)), improving over O(log(N)log(N/ϵ))O(\log(N)\log(N/\epsilon)) and O(Nlog(N/ϵ))O(N\log(N/\epsilon)), respectively. We illustrate how the reduced spacetime allocation of our protocol enables rapid preparation of many disjoint states with only constant-factor ancilla overhead -- O(N)O(N) ancilla qubits are reused efficiently to prepare a product state of ww NN-dimensional states in depth O(w+log(N))O(w + \log(N)) rather than O(wlog(N))O(w\log(N)), achieving effectively constant depth per state. We highlight several applications where this ability would be useful, including quantum machine learning, Hamiltonian simulation, and solving linear systems of equations. We provide quantum circuit descriptions of our protocol, detailed pseudocode, and gate-level implementation examples using Braket

    The extraforaminal juxtafacet cyst as a rare cause of L5 radiculopathy: a case report.

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    STUDY DESIGN: This is a report of a case. OBJECTIVE: To document the clinical, radiographic, and histologic characteristics of a lumbar extraforaminal juxtafacet cyst. SUMMARY OF BACKGROUND DATA: Spinal juxtafacet cysts develop most frequently at the dorsal aspect of the zygapophysial joint, sometimes in the posterolateral area of the canal. In one case, they have been described in the foraminal and extraforaminal region. METHODS: Description of the case report. RESULT: The authors report one case of a strictly extraforaminal juxtafacet cyst responsible for L5 sciatica. CONCLUSIONS: Juxtafacet cysts of the spine represent an infrequent cause of sciatica, usually when they grow in the canal, or more exceptionally when they occupy the foraminal or extraforaminal areas

    Extended high efficacy of the combination sulphadoxine-pyrimethamine with artesunate in children with uncomplicated falciparum malaria on the Benin coast, West Africa

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    <p>Abstract</p> <p>Background</p> <p>A study carried out in 2003–2005 in Southern Benin showed a day-28 sulphadoxine-pyrimethamine (SP) monotherapy failure rate greater than 40%, while for SP combined with artesunate (SP-AS) the failure rate was 5.3%. Such a large difference could be explained by the relatively short 28-day follow-up period, with a substantial number of recurrent infections possibly occurring after day 28. This paper reports the treatment outcome observed in the same study cohort beyond the initial 28-day follow-up.</p> <p>Methods</p> <p>After the 28-day follow-up, children treated with either chloroquine alone (CQ), SP or SP-AS, were visited at home twice a week until day 90 after treatment. A blood sample was collected if the child had fever (axillary temperature ≥37.5°C). Total clinical failure for each treatment group was estimated by combining all the early treatment failures and late clinical failures that occurred over the whole follow-up period, i.e. from day 0 up to day 90. Pre-treatment randomly selected blood samples were genotyped for the <it>dhfr </it>gene (59) and the <it>dhps </it>gene (437 and 540) point mutations related to SP resistance.</p> <p>Results</p> <p>The PCR-corrected clinical failure at day 90 was significantly lower in the SP-AS group (SP-AS: 2.7%, SP alone: 38.2%; CQ: 41.1%) (Log-Rank p < 0,001). The most prevalent haplotype was <it>dhfr </it>Arg-59 with the <it>dhps </it>Gly-437 mutant and the <it>dhps </it>540 wild type (85.5%). The <it>dhps </it>540 mutation could be found in only three (8.3%) samples.</p> <p>Conclusion</p> <p>Combining artesunate to SP dramatically increased the treatment efficacy, even when extending the follow-up to day 90 post-treatment, and despite the high percentage of failures following treatment with SP alone. Such a good performance may be explained by the low prevalence of the <it>dhps </it>540 mutation, by the rapid parasite clearance with artesunate and by the level of acquired immunity.</p

    Visual loss alters multisensory face maps in humans

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    Topographically organised responses to visual and tactile stimulation are aligned in the ventral intraparietal cortex. The critical biological importance of this region, which is thought to mediate visually guided defensive movements of the head and upper body, suggests that these maps might be hardwired from birth. Here, we investigated whether visual experience is necessary for the creation and positioning of these maps by assessing the representation of tactile stimulation in congenitally and totally blind participants, who had no visual experience, and late and totally blind participants. We used a single-subject approach to the analysis to focus on the potential individual differences in the functional neuroanatomy that might arise from different causes, durations and sensory experiences of visual impairment among participants. The overall results did not show any significant difference between congenitally and late blind participants; however, single-subject trends suggested that visual experience is not necessary to develop topographically organised maps in the intraparietal cortex, whilst losing vision disrupted topographic maps’ integrity and organisation. These results discussed in terms of brain plasticity and sensitive periods

    Adding artesunate to sulphadoxine-pyrimethamine greatly improves the treatment efficacy in children with uncomplicated falciparum malaria on the coast of Benin, West Africa

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    <p>Abstract</p> <p>Background</p> <p>Benin has recently shifted its national antimalarial drug policy from monotherapies to combinations containing artemisinin derivatives. When this decision was taken, the available information on alternatives to chloroquine and sulphadoxine-pyrimethamine, the first- and second-line treatment, was sparse.</p> <p>Methods</p> <p>In 2003 – 2005, before the drug policy change, a randomized, open-label, clinical trial was carried out on the efficacy of chloroquine, and sulphadoxine-pyrimethamine alone or combined with artesunate, with the aim of providing policy makers with the information needed to formulate a new antimalarial drug policy. Children between six and 59 months of age, with uncomplicated malaria and living in the lagoon costal area in southern Benin, were randomly allocated to one of the three study arms and followed up for 28 days.</p> <p>Results</p> <p>Treatment failure (PCR corrected) was significantly lower in the artesunate + sulphadoxine-pyrimethamine group (4/77, 5.3%) than in chloroquine group(51/71, 71.8%) or the sulphadoxine-pyrimethamine alone group (30/70, 44.1%) (p < 0.001). Despite high sulphadoxine-pyrimethamine failure, its combination with artesunate greatly improved treatment efficacy.</p> <p>Conclusion</p> <p>In Benin, artesunate + sulphadoxine-pyrimethamine is efficacious and could be used when the recommended artemisinin-based combinations (artemether-lumefantrine and amodiaquine-artesunate) are not available. However, because sulphadoxine-pyrimethamine is also used in pregnant women as intermittent preventive treatment, its combination with artesunate should not be widely employed in malaria patients as this may compromise the efficacy of intermittent preventive treatment.</p

    Euclid-Roman joint microlensing survey: early mass measurement, free floating planets and exomoons

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    Funding: EB gratefully acknowledge support from NASA grant 80NSSC19K0291. The work of DS is funded by a UK Science and Technology Facilities Council (STFC) PhD studentship. EK also acknowledges support from the STFC. EB, JPB and CR’s work was carried out within the framework of the ANR project COLD-WORLDS supported by the French National Agency for Research with the reference ANR-18-CE31-0002. JPB was supported by the University of Tasmania through the UTAS Foundation, ARC grant DP200101909 and the endowed Warren Chair in Astronomy. JR was supported by NASA ROSES grant 12-EUCLID12-0004, the Nancy Grace Roman Telescope, and JPL, which is run by Caltech under a contract for NASA. RP was supported by the Polish National Agency for Academic Exchange via Polish Returns 2019 grant. DM acknowledges support by the European Research Council (ERC) under the European Union’s FP7 Programme, Grant No. 833031.As the Kepler mission has done for hot exoplanets, the ESA Euclid and NASA Roman missions have the potential to create a breakthrough in our understanding of the demographics of cool exoplanets, including unbound, or "free-floating", planets (FFPs). In this study, we demonstrate the complementarity of the two missions and propose two joint-surveys to better constrain the mass and distance of microlensing events. We first demonstrate that an early brief Euclid survey (7 h) of the Roman microlensing fields will allow the measurement of a large fraction of events relative proper motions and lens magnitudes. Then, we study the potential of simultaneous observations by Roman and Euclid to enable the measurement of the microlensing parallax for the shortest microlensing events. Using detailed simulations of the joint detection yield we show that within one year Roman-Euclid observations will be at least an order of magnitude more sensitive than current ground-based measurements. Depending on the exact distribution of FFP, a joint Roman-Euclid campaign should detect around 130 FFP events within a year, including 110 with measured parallax that strongly constrain the FFP mass, and around 30 FFP events with direct mass and distance measurements. The ability of the joint survey to completely break the microlens mass-distance-velocity degeneracy for a significant subset of events provides a unique opportunity to verify unambiguously the FFP hypothesis or else place abundance limits for FFPs between Earth and Jupiter masses that are up to two orders of magnitude stronger than provided by ground-based surveys. Finally, we study the capabilities of the joint survey to enhance the detection and charcterization of exomoons, and found that it could lead to the detection of the first exomoon.PostprintPeer reviewe

    In-line metrology for roll-to-roll UV assisted nanoimprint lithography using diffractometry

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    En publicar-se l'article, l'autor Martin Kreuzer treballa a: ALBA Laboratori de Llum de SincrotróWe describe and discuss the optical design of a diffractometer to carry out in-line quality control during roll-to-roll nanoimprinting. The tool measures diffractograms in reflection geometry, through an aspheric lens to gain fast, non-invasive information of any changes to the critical dimensions of target grating structures. A stepwise tapered linear grating with constant period was fabricated in order to detect the variation in grating linewidth through diffractometry. The minimum feature change detected was ∼40 nm to a precision of 10 nm. The diffractometer was then integrated with a roll-to-roll UV assisted nanoimprint lithography machine to gain dynamic measurements in situ
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