226 research outputs found

    Quantum state tomography and quantum logical operations in a three qubits NMR quadrupolar system

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    In this work, we present an implementation of quantum logic gates and algorithms in a three effective qubits system, represented by a (I = 7/2) NMR quadrupolar nuclei. To implement these protocols we have used the strong modulating pulses (SMP). The various stages of each implementation were verified by quantum state tomography (QST). It is presented here the results for the computational base states, Toffolli logic gates, and Deutsch-Jozsa and Grover algorithms. Also, we discuss the difficulties and advantages of implementing such protocols using the SMP technique in quadrupolar systems.Comment: 24 pages, 8 figure

    Setting The Pace: Examining Cognitive Processing in MOOC Discussion Forums With Automatic Text Analysis

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    Learning analytics focuses on extracting meaning from large amounts of data. One of the largest datasets in education comes from Massive Open Online Courses (MOOCs) that typically feature enrollments in the tens of thousands. Analyzing MOOC discussion forums presents logistical issues, resulting chiefly from the size of the dataset, which can create challenges for understanding and adequately describing student behaviors. Utilizing automatic text analysis, this study built a hierarchical linear model that examines the influence of the pacing condition of a massive open online course (MOOC), whether it is self-paced or instructor-paced, on the demonstration of cognitive processing in a HarvardX MOOC. The analysis of 2,423 discussion posts generated by 671 students revealed the number of dictionary words used were positively associated with cognitive processing while analytical thinking and clout was negatively associated. We found that none of the student background information (gender, education), status of the course engagement (explored or completed), or the course pace (self-paced versus instructor paced) significantly influenced the cognitive processing of the postings

    User Evaluation of Advanced Interaction Features for a Computer-Assisted Translation Workbench

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    This paper reports on the results of a user satisfaction survey carried out among 16 translators using a new computer-assisted translation workbench. Participants were asked to provide feedback after performing different post-editing tasks on different configurations of the workbench, using different features and tools. Resulting from the feedback provided, we report on the utility of each of the features, identifying new ways of implementing them according to the users’ suggestions

    Association of Accelerometry-Measured Physical Activity and Cardiovascular Events in Mobility-Limited Older Adults: The LIFE (Lifestyle Interventions and Independence for Elders) Study.

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    BACKGROUND:Data are sparse regarding the value of physical activity (PA) surveillance among older adults-particularly among those with mobility limitations. The objective of this study was to examine longitudinal associations between objectively measured daily PA and the incidence of cardiovascular events among older adults in the LIFE (Lifestyle Interventions and Independence for Elders) study. METHODS AND RESULTS:Cardiovascular events were adjudicated based on medical records review, and cardiovascular risk factors were controlled for in the analysis. Home-based activity data were collected by hip-worn accelerometers at baseline and at 6, 12, and 24 months postrandomization to either a physical activity or health education intervention. LIFE study participants (n=1590; age 78.9±5.2 [SD] years; 67.2% women) at baseline had an 11% lower incidence of experiencing a subsequent cardiovascular event per 500 steps taken per day based on activity data (hazard ratio, 0.89; 95% confidence interval, 0.84-0.96; P=0.001). At baseline, every 30 minutes spent performing activities ≄500 counts per minute (hazard ratio, 0.75; confidence interval, 0.65-0.89 [P=0.001]) were also associated with a lower incidence of cardiovascular events. Throughout follow-up (6, 12, and 24 months), both the number of steps per day (per 500 steps; hazard ratio, 0.90, confidence interval, 0.85-0.96 [P=0.001]) and duration of activity ≄500 counts per minute (per 30 minutes; hazard ratio, 0.76; confidence interval, 0.63-0.90 [P=0.002]) were significantly associated with lower cardiovascular event rates. CONCLUSIONS:Objective measurements of physical activity via accelerometry were associated with cardiovascular events among older adults with limited mobility (summary score >10 on the Short Physical Performance Battery) both using baseline and longitudinal data. CLINICAL TRIAL REGISTRATION:URL: http://www.clinicaltrials.gov. Unique identifier: NCT01072500

    Generalized Structural Description of Calcium–Sodium Aluminosilicate Hydrate Gels: The Cross-Linked Substituted Tobermorite Model

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    Structural models for the primary strength and durability-giving reaction product in modern cements, a calcium (alumino)silicate hydrate gel, have previously been based solely on non-cross-linked tobermorite structures. However, recent experimental studies of laboratory-synthesized and alkali-activated slag (AAS) binders have indicated that the calcium–sodium aluminosilicate hydrate [C-(N)-A-S-H] gel formed in these systems can be significantly cross-linked. Here, we propose a model that describes the C-(N)-A-S-H gel as a mixture of cross-linked and non-cross-linked tobermorite-based structures (the cross-linked substituted tobermorite model, CSTM), which can more appropriately describe the spectroscopic and density information available for this material. Analysis of the phase assemblage and Al coordination environments of AAS binders shows that it is not possible to fully account for the chemistry of AAS by use of the assumption that all of the tetrahedral Al is present in a tobermorite-type C-(N)-A-S-H gel, due to the structural constraints of the gel. Application of the CSTM can for the first time reconcile this information, indicating the presence of an additional activation product that contains highly connected four-coordinated silicate and aluminate species. The CSTM therefore provides a more advanced description of the chemistry and structure of calcium–sodium aluminosilicate gel structures than that previously established in the literature

    Formation and modern state of ecosystem in Tolmachevskoye reservoir (Kamchatka) and the acclimatized there population of kokanee ( <i>Oncorhynchus nerka kennerlyi</i>)

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    Evolution of local ecosystem in Tolmachevskoye reservoir and changes in its artificial population of kokanee salmon are traced on the data of authors’ observations in 2009-2013 and previous archival and cited data. Decreasing of inorganic phosphorous, nitrogen, and bioavailable iron is detected in the water against a background of water warming. As the result, phytoplankton production and abundance decrease, its species composition becomes simpler, chlorophyll Đ° concentration becomes lower. Zooplankton abundance is stable (1-2 g/m3), as before the reservoir appearance, but species structure of plankton crustaceans is changed, and the copepods Cyclops scutifer , small cladocerans Holopedium gibberum, Bosmina longirostris , and Daphnia ( Daphnia ) cristata group prevail recently. The salmon food spectrum is wide and includes a lot of unedible fractions as wood chips and plant detritus; coefficient of consumption is high - these factors indicate a deficiency of forage resources for fish. The fish condition indicates a chronic malnutrition. The state of female gonads is satisfactory, without any visible pathology, as in 2003-2007, but the oocytes resorption goes concurrently with maturation of gonads that is a sign of hard competition for the food within the kokanee population. The current stable state of the population differs from preceded stages of its development by lower stock add smaller size of fish, the age of spawning is now 4-7 years. Among other freshwater fish, the kokanee salmon is distinguished by high content of ω-3 polyunsaturated fatty acids. Artificial populations in Kamchatka could be considered as a resource for both amateur or sport fishing and commercial aquaculture
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