453 research outputs found
Quantifying quantum speedups: improved classical simulation from tighter magic monotones
Consumption of magic states promotes the stabilizer model of computation to
universal quantum computation. Here, we propose three different classical
algorithms for simulating such universal quantum circuits, and characterize
them by establishing precise connections with a family of magic monotones. Our
first simulator introduces a new class of quasiprobability distributions and
connects its runtime to a generalized notion of negativity. We prove that this
algorithm has significantly improved exponential scaling compared to all prior
quasiprobability simulators for qubits. Our second simulator is a new variant
of the stabilizer-rank simulation algorithm, extended to work with mixed states
and with significantly improved runtime bounds. Our third simulator trades
precision for speed by discarding negative quasiprobabilities. We connect each
algorithm's performance to a corresponding magic monotone and, by
comprehensively characterizing the monotones, we obtain a precise understanding
of the simulation runtime and error bounds. Our analysis reveals a deep
connection between all three seemingly unrelated simulation techniques and
their associated monotones. For tensor products of single-qubit states, we
prove that our monotones are all equal to each other, multiplicative and
efficiently computable, allowing us to make clear-cut comparisons of the
simulators' performance scaling. Furthermore, our monotones establish several
asymptotic and non-asymptotic bounds on state interconversion and distillation
rates. Beyond the theory of magic states, our classical simulators can be
adapted to other resource theories under certain axioms, which we demonstrate
through an explicit application to the theory of quantum coherence.Comment: 24+13 pages, 8 figures; final author copy. Since v1: restructured
with additional discussion, proof sketches and examples. Since v3: minor
revisions to improve clarity, additional acknowledgment
Technology generation to dissemination:lessons learned from the tef improvement project
Indigenous crops also known as orphan crops are key contributors to food security, which is becoming increasingly vulnerable with the current trend of population growth and climate change. They have the major advantage that they fit well into the general socio-economic and ecological context of developing world agriculture. However, most indigenous crops did not benefit from the Green Revolution, which dramatically increased the yield of major crops such as wheat and rice. Here, we describe the Tef Improvement Project, which employs both conventional- and molecular-breeding techniques to improve tef\u2014an orphan crop important to the food security in the Horn of Africa, a region of the world with recurring devastating famines. We have established an efficient pipeline to bring improved tef lines from the laboratory to the farmers of Ethiopia. Of critical importance to the long-term success of this project is the cooperation among participants in Ethiopia and Switzerland, including donors, policy makers, research institutions, and farmers. Together, European and African scientists have developed a pipeline using breeding and genomic tools to improve the orphan crop tef and bring new cultivars to the farmers in Ethiopia. We highlight a new variety, Tesfa, developed in this pipeline and possessing a novel and desirable combination of traits. Tesfa\u2019s recent approval for release illustrates the success of the project and marks a milestone as it is the first variety (of many in the pipeline) to be released
Иммунно-нейроэндокринные взаимосвязи в развитии перименопаузальной патологии
Представлен современный патогенетический взгляд на происходящие в перименопаузальном периоде системные нарушения. Показано, что имунно-нейроэндокринный гомеостаз имеет определенные отличия в зависимости от клинической формы и степени тяжести перименопаузальных нарушений, что необходимо учитывать при проведении терапевтических мероприятий.Представлено сучасний патогенетичний погляд на системні порушення, що відбуваються в перименопаузальному періоді. Показано, що імунно-нейроендокринний гомеостаз має певні відмінності залежно від клінічної форми і ступеня тяжкості перименопаузальних порушень, що необхідно враховувати під час проведення терапевтичних заходів.A modern pathogenetic opinion about the systemic perimenopausal disorders is presented. It is shown that immunoneuroendocrine homeostatsis differs depending on the clinical form and degree of severity of perimenopausal disorders, which should be taken into consideration when taking therapeutic measures
Transanal endoscopic microsurgery versus endoscopic mucosal resection for large rectal adenomas (TREND-study)
Background: Recent non-randomized studies suggest that extended endoscopic mucosal resection (EMR) is equally effective in removing large rectal adenomas as transanal endoscopic microsurgery (TEM). If equally effective, EMR might be a more cost-effective approach as this strategy does not require expensive equipment, general anesthesia and hospital admission. Furthermore, EMR appears to be associated with fewer complications. The aim of this study is to compare the cost-effectiveness and cost-utility of TEM and EMR for the resection of large rectal adenomas. Methods/design. Multicenter randomized trial among 15 hospitals in the Netherlands. Patients with a rectal adenoma 3 cm, located between 115 cm ab ano, will be randomized to a TEM- or EMR-treatment strategy. For TEM, patients will be treated under general anesthesia, adenomas will be dissected en-bloc by a full-thickness excision, and patients will be admitted to the hospital. For EMR, no or conscious sedation is used, lesions will be resected through the submucosal plane i
Gender inequalities in transnational academic mobility and the ideal type of academic entrepreneur
Structure-Based Prediction of Asparagine and Aspartate Degradation Sites in Antibody Variable Regions
Monoclonal antibodies (mAbs) and proteins containing antibody domains are the most prevalent class of biotherapeutics in diverse indication areas. Today, established techniques such as immunization or phage display allow for an efficient generation of new mAbs. Besides functional properties, the stability of future therapeutic mAbs is a key selection criterion which is essential for the development of a drug candidate into a marketed product. Therapeutic proteins may degrade via asparagine (Asn) deamidation and aspartate (Asp) isomerization, but the factors responsible for such degradation remain poorly understood. We studied the structural properties of a large, uniform dataset of Asn and Asp residues in the variable domains of antibodies. Their structural parameters were correlated with the degradation propensities measured by mass spectrometry. We show that degradation hotspots can be characterized by their conformational flexibility, the size of the C-terminally flanking amino acid residue, and secondary structural parameters. From these results we derive an accurate in silico prediction method for the degradation propensity of both Asn and Asp residues in the complementarity-determining regions (CDRs) of mAbs
Strain building and correlation with grain nucleation during silicon growth
This work is dedicated to the grain structure formation in silicon ingots with a particular focus on the crystal structure strain building and its implication in new grain nucleation process. The implied mechanisms are investigated by advanced in situ X-ray imaging techniques during silicon directional solidification. It is shown that the grain structure formation is mainly driven by S3 twin nucleation. Grain competition phenomena occurring during the growth process lead to the creation of higher order twin boundaries, localised strained areas and associated crystal structure deformation. On the one hand, it is demonstrated that local strain building can be directly related to the characteristics of the twin boundaries created during silicon growth due to grain competition. On the other hand, space restriction due to competition during growth can be at the origin of local strain building as well. Finally, the accumulation of all these factors generating strain is responsible for spontaneous new grain nucleation. When occurring, both grain nucleation and subsequent grain structure reorganisation contribute to lower the strain in the growing ingot. It is demonstrated as well that the local distribution of the strained areas created during silicon growth is retrieved after cooling down, from melting temperature to room temperature, on top of an additional larger scale deformation of the sample due to the cooling down only
Self-help for stress and burnout without therapist contact: An online randomised controlled trial
Interventions designed to reduce stress and burnout may be costly and access is limited. This study examined the effectiveness of a self-help book, using Acceptance and commitment therapy (ACT) to target stress and burnout in a randomised controlled online trial without any therapist contact. Participants were recruited through a newsletter of a health insurance company. Participants ( N = 119) who reported at least moderate levels of stress were randomly assigned to an immediate intervention ( n = 61) or a waitlist group ( n = 58). Measures before and after the intervention assessed stress, burnout (primary outcomes), depression, well-being, emotion regulation (secondary outcomes) and ACT-specific constructs. Compared to the waitlist group, participants in the immediate intervention group reported lower stress and burnout and higher psychological flexibility at post-assessment. Effects between groups were large for stress ( d = 0.9), moderate to large for burnout ( d = 0.5–0.8) and large for psychological flexibility ( d = 0.8). All primary and most secondary outcomes and ACT processes continued to improve in the 3-month-follow-up period. Results suggest that an ACT self-help book without any therapist contact is effective in reducing stress and burnout for various occupations. Thus, it may provide a cost-effective public health intervention for reducing stress and burnout
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