Mit Ionen ist zu rechnen Linke, Norbert; Müller, Markus
Physik in unserer Zeit,
07/2020, Letnik:
51, Številka:
4
Journal Article
ZusammenfassungQuantencomputer versprechen, spezielle, für Anwendungen hochinteressante Aufgaben zu lösen. An diesen NP‐harten Problemen scheitern herkömmliche Supercomputer. Eine Technik, die ...intensiv erforscht wird, ist der Ionen‐Quantencomputer. An ihm demonstriert dieser Artikel, wie der Quanten‐Suchalgorithmus von Lov Grover funktioniert. Programmiert werden solche Quantencomputer über einen Software‐Stack. Er übersetzt die Befehle der Nutzeroberfläche über verschiedene Stufen in die Laser‐Manipulation der Ionen‐Qubits. Bei den aktuell in Laboren laufenden Quantencomputern sind etwa zehn Ionen die Grenze, ab der das Rauschen der Quantengatter für zu große Fehler in den Rechnungen sorgt. In Zukunft soll eine Quantenfehlerkorrektur, die mehrere physische Qubits zu einem logischen Qubit verknüpft, Fehler erkennen können. Um die Zahl der Ionen zu steigern, soll die Kontrolle über die Laserpulse und die Fallenpotenziale verbessert werden. Zudem wird daran geforscht, mehrere Ionenfallen zum Beispiel via Photonenverschränkung miteinander zu verbinden. Mikrochip‐Ionenfallen sollen Ionen‐Quantencomputer miniaturisieren.
Tactile sensing is a key sensor modality for robots interacting with their surroundings. These sensors provide a rich and diverse set of data signals that contain detailed information collected from ...contacts between the robot and its environment. The data are however not limited to individual contacts and can be used to extract a wide range of information about the objects in the environment as well as the actions of the robot during the interactions. In this article, we provide an overview of tactile information and its applications in robotics. We present a hierarchy consisting of raw, contact, object, and action levels to structure the tactile information, with higher-level information often building upon lower-level information. We discuss different types of information that can be extracted at each level of the hierarchy. The article also includes an overview of different types of robot applications and the types of tactile information that they employ. Finally we end the article with a discussion for future tactile applications which are still beyond the current capabilities of robots.
Realizing arbitrary manipulation of optical waves, which still remains a challenge, plays a key role in the implementation of optical devices with on‐demand functionalities. However, it is hard to ...independently manipulate multiple dimensions of optical waves because the optical dimensions are basically associated with each other when adjusting the optical response of the devices. Here, the concise design principle of a chiral mirror is utilized to realize the full‐dimensional independent manipulation of circular‐polarized waves. By simply changing three structural variables of the chiral mirror, the proposed design principle can arbitrarily and independently empower the spin‐selective manipulation of amplitude, phase, and operation wavelength of circular‐polarized waves with a large modulation depth. This approach provides a simple solution for the realization of spin‐selective full‐dimensional manipulation of optical waves and shows ample application possibilities in the areas of optical encryption, imaging, and detection.
A new design principle of chiral mirrors is proposed to realize full‐dimensional independent manipulation of circular‐polarized waves. By simply changing three structural variables of the chiral mirrors, the proposed design principle can arbitrarily and independently empower the spin‐selective manipulation of amplitude, phase, and operation wavelength of circular‐polarized waves with a large modulation depth.
The purpose of this scoping review was to evaluate and characterize the scope of care for low back pain that falls under the specific label of manual therapy.
PubMed database, Ovid MEDLINE, EMBASE, ...Cumulative Index to Nursing and Allied Health Literature (CINAHL), Cochrane Central Register of Controlled Trials (CENTRAL), and SPORTDiscus were searched from journal inception through May 2022 for randomized controlled trials that investigated the treatment of low back pain using manual therapy. Terminology used to define manual therapy was extracted and categorized by using only the words included in the description of the intervention. An expert consultation phase was undertaken to gather feedback.
One hundred seventy-six trials met final inclusion criteria, and 169 unique terms labeled as manual therapy for the treatment of low back pain were found. The most frequent terms were mobilization (29.0%), manipulation (16.0%), and thrust (6.4%). Eight percent of trials did not define or specify what type of manual therapy was used in the study. After removing duplicates, 169 unique terms emerged within 18 categories.
Manual therapy intervention labels used in low back pain trials are highly variable. With such variation, the heterogeneity of the intervention in trials is likely large, and the likelihood that different trials are comparing the same interventions is low. Researchers should consider being more judicious with the use of the term manual therapy and provide greater detail in titles, methods, and supplementary appendices in order to improve clarity, clinical applicability, and usefulness of future research.
The ability to interpret and apply findings from manual therapy-related research for low back pain is challenging due to the heterogeneity of interventions under this umbrella term. A clear use of terminology and description of interventions by researchers will allow for improved understanding for the role of manual therapy in managing back pain.
In this article, we present the RBO Hand 3 , a highly capable and versatile anthropomorphic soft hand based on pneumatic actuation. The RBO Hand 3 is designed to enable dexterous manipulation, to ...facilitate transfer of insights about human dexterity, and to serve as a robust research platform for extensive real-world experiments. It achieves these design goals by combining many degrees of actuation with intrinsic compliance, replicating relevant functioning of the human hand, and by combining robust components in a modular design. The RBO Hand 3 possesses 16 independent degrees of actuation, implemented in a dexterous opposable thumb, two-chambered fingers, an actuated palm, and the ability to spread the fingers. In this article, we derive the design objectives that are based on experimentation with the hand's predecessors, observations about human grasping, and insights about principles of dexterity. We explain in detail how the design features of the RBO Hand 3 achieve these goals and evaluate the hand by demonstrating its ability to achieve the highest possible score in the Kapandji test for thumb opposition, to realize all 33 grasp types of the comprehensive GRASP taxonomy, to replicate common human grasping strategies, and to perform dexterous in-hand manipulation.
•This paper conducts an empirical study on how review manipulation affects sales.•We examine the heterogeneous effects of review manipulation in three dimensions.•We provide a theoretical explanation ...on the heterogeneous impacts.•We reveal the magnitude of the effect of review manipulation.
In recent years, there has been an increase in online review manipulation on the platforms of electronic commerce. Previous studies clarify the benefits and harms of online review manipulation for firms, and they provide mixed conclusions on the influence of online review manipulation. However, the effect of online review manipulation on product sales has not yet been thoroughly studied due to the covert nature of review manipulation. To fill this research gap, this paper examines the different effects of review manipulation in three dimensions: quantity manipulation, quality manipulation, and relation manipulation. Drawing on the Information Manipulation Theory, which reveals the manipulation behaviors of different dimensions, it is proposed that the influence of online review manipulation differs significantly among different information manipulation dimensions. The results of the empirical experiments show that the effect of review quantity manipulation on product sales exhibits an inverted U-shape. In addition, review quality manipulation positively affects product sales, but review relation manipulation exerts a negative effect. Moreover, the magnitude of the effect of review manipulation is contingent upon review manipulation duration. The findings shed light on the heterogeneous effect of review manipulation dimensions on product sales from an information manipulation perspective and suggest a need for improvement in online fraudulent review detection in the early stage of review manipulation.
AbstractObjectiveTo assess the benefits and harms of spinal manipulative therapy (SMT) for the treatment of chronic low back pain.DesignSystematic review and meta-analysis of randomised controlled ...trials.Data sourcesMedline, PubMed, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), CINAHL, Physiotherapy Evidence Database (PEDro), Index to Chiropractic Literature, and trial registries up to 4 May 2018, including reference lists of eligible trials and related reviews.Eligibility criteria for selecting studiesRandomised controlled trials examining the effect of spinal manipulation or mobilisation in adults (≥18 years) with chronic low back pain with or without referred pain. Studies that exclusively examined sciatica were excluded, as was grey literature. No restrictions were applied to language or setting.Review methodsTwo reviewers independently selected studies, extracted data, and assessed risk of bias and quality of the evidence. The effect of SMT was compared with recommended therapies, non-recommended therapies, sham (placebo) SMT, and SMT as an adjuvant therapy. Main outcomes were pain and back specific functional status, examined as mean differences and standardised mean differences (SMD), respectively. Outcomes were examined at 1, 6, and 12 months. Quality of evidence was assessed using GRADE. A random effects model was used and statistical heterogeneity explored.Results47 randomised controlled trials including a total of 9211 participants were identified, who were on average middle aged (35-60 years). Most trials compared SMT with recommended therapies. Moderate quality evidence suggested that SMT has similar effects to other recommended therapies for short term pain relief (mean difference −3.17, 95% confidence interval −7.85 to 1.51) and a small, clinically better improvement in function (SMD −0.25, 95% confidence interval −0.41 to −0.09). High quality evidence suggested that compared with non-recommended therapies SMT results in small, not clinically better effects for short term pain relief (mean difference −7.48, −11.50 to −3.47) and small to moderate clinically better improvement in function (SMD −0.41, −0.67 to −0.15). In general, these results were similar for the intermediate and long term outcomes as were the effects of SMT as an adjuvant therapy. Evidence for sham SMT was low to very low quality; therefore these effects should be considered uncertain. Statistical heterogeneity could not be explained. About half of the studies examined adverse and serious adverse events, but in most of these it was unclear how and whether these events were registered systematically. Most of the observed adverse events were musculoskeletal related, transient in nature, and of mild to moderate severity. One study with a low risk of selection bias and powered to examine risk (n=183) found no increased risk of an adverse event (relative risk 1.24, 95% confidence interval 0.85 to 1.81) or duration of the event (1.13, 0.59 to 2.18) compared with sham SMT. In one study, the Data Safety Monitoring Board judged one serious adverse event to be possibly related to SMT.ConclusionSMT produces similar effects to recommended therapies for chronic low back pain, whereas SMT seems to be better than non-recommended interventions for improvement in function in the short term. Clinicians should inform their patients of the potential risks of adverse events associated with SMT.
Planar in-hand manipulation via motion cones Chavan-Dafle, Nikhil; Holladay, Rachel; Rodriguez, Alberto
The International journal of robotics research,
03/2020, Letnik:
39, Številka:
2-3
Journal Article
Recenzirano
Odprti dostop
In this article, we present the mechanics and algorithms to compute the set of feasible motions of an object pushed in a plane. This set is known as the motion cone and was previously described for ...non-prehensile manipulation tasks in the horizontal plane. We generalize its construction to a broader set of planar tasks, such as those where external forces including gravity influence the dynamics of pushing, or prehensile tasks, where there are complex frictional interactions between the gripper, object, and pusher. We show that the motion cone is defined by a set of low-curvature surfaces and approximate it by a polyhedral cone. We verify its validity with thousands of pushing experiments recorded with a motion tracking system. Motion cones abstract the algebra involved in the dynamics of frictional pushing and can be used for simulation, planning, and control. In this article, we demonstrate their use for the dynamic propagation step in a sampling-based planning algorithm. By constraining the planner to explore only through the interior of motion cones, we obtain manipulation strategies that are robust against bounded uncertainties in the frictional parameters of the system. Our planner generates in-hand manipulation trajectories that involve sequences of continuous pushes, from different sides of the object when necessary, with 5–1,000 times speed improvements to equivalent algorithms.
Metasurfaces, 2D artificial arrays of subwavelength elements, have attracted great interest from the optical scientific community in recent years because they provide versatile possibilities for the ...manipulation of optical waves and promise an effective way for miniaturization and integration of optical devices. In the past decade, the main efforts were focused on the realization of single‐dimensional (amplitude, frequency, polarization, or phase) manipulation of optical waves. Compared to the metasurfaces with single‐dimensional manipulation, metasurfaces with multidimensional manipulation of optical waves show significant advantages in many practical application areas, such as optical holograms, sub‐diffraction imaging, and the design of integrated multifunctional optical devices. Nowadays, with the rapid development of nanofabrication techniques, the research of metasurfaces has been inevitably developed from single‐dimensional manipulation toward multidimensional manipulation of optical waves, which greatly boosts the application of metasurfaces and further paves the way for arbitrary design of optical devices. Herein, the recent advances in metasurfaces are briefly reviewed and classified from the viewpoint of different dimensional manipulations of optical waves. Single‐dimensional manipulation and 2D manipulation of optical waves with metasurfaces are discussed systematically. In conclusion, an outlook and perspectives on the challenges and future prospects in these rapidly growing research areas are provided.
Realizing optical wave manipulation in arbitrary dimension with metasurfaces indicates a bright future for the real application of artificial nanostructures. A classification of metasurfaces is provided from the viewpoint of the different dimensional manipulations of optical waves. Furthermore, the development trend of metasurfaces for effective dimensional manipulation of optical waves is shown.
Warping Time Ginsberg, Benjamin; Bachner, Jennifer
04/2023
eBook
Odprti dostop
Warping Time shows how narratives of the past influence what people believe about the present and future state of the world. In Benjamin Ginsberg and Jennifer Bachner’s simple experiments, in which ...the authors measured the impact of different stories their subjects heard about the past, these “history lessons” moved contemporary policy preferences by an average of 16 percentage points; forecasts of the future moved contemporary policy preferences by an average of 12 percentage points; the two together moved preferences an average of 21 percentage points. And, in an Orwellian twist, the authors estimate that the “history lessons” had an average “erasure effect” of 8.5 percentage points—the difference between those with long-held preferences and those who did not recall that they previously held other opinions before participating in the experiment. The fact that the past, present, and future are subject to human manipulation suggests that history is not simply the product of impersonal forces, material conditions, or past choices. Humans are the architects of history, not its captives. Political reality is tenuous. Changes in our understanding of the past or future can substantially alter perceptions of and action in the present. Finally, the manipulation of time, especially the relationship between past and future, is a powerful political tool.
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