2,621 research outputs found
Edge local complementation for logical cluster states
A method is presented for the implementation of edge local complementation in
graph states, based on the application of two Hadamard operations and a single
controlled-phase (CZ) gate. As an application, we demonstrate an efficient
scheme to construct a one-dimensional logical cluster state based on the
five-qubit quantum error-correcting code, using a sequence of edge local
complementations. A single physical CZ operation, together with local
operations, is sufficient to create a logical CZ operation between two logical
qubits. The same construction can be used to generate any encoded graph state.
This approach in concatenation may allow one to create a hierarchical quantum
network for quantum information tasks.Comment: 15 pages, two figures, IOP styl
Algebraic invariants of five qubits
The Hilbert series of the algebra of polynomial invariants of pure states of
five qubits is obtained, and the simplest invariants are computed.Comment: 4 pages, revtex. Short discussion of quant-ph/0506073 include
Human ankle joint movements during walking are probably not determined by talar morphology.
Knowledge about the orientation of a representative ankle joint axis is limited to studies of tarsal morphology and of quasistatic movements. The aim of our study was therefore to determine the development of the axis orientation during walking. Intracortical bone pins were used to monitor the kinematics of the talus and tibia of five healthy volunteers. The finite helical axis was determined for moving windows of 10% stance phase and its orientation reported if the rotation about the axis was more than 2°. A representative axis for ankle dorsi- and plantarflexion was also estimated based on tarsal morphology. As reported by literature, the morphology-based axis was inclined more medially upwards for dorsiflexion than for plantarflexion. However, when a mean of the finite helical axis orientations was calculated for each walking trial for dorsiflexion (stance phase 15-25%) and for plantarflexion (stance phase 85-95%), the inclination was less medially upwards in dorsiflexion than in plantarflexion in four out of five participants. Thus, it appears that the inclination of a representative ankle joint axis for dynamic loading situations cannot be estimated from either morphology or quasi-static experiments. Future studies assessing muscle activity, ligament behaviour and articulating surfaces may help to identify the determining factors for the orientation of a representative ankle joint axis
The Rapid Outbursting Star GM Cep: An EX-or in Tr 37?
We present optical, IR and millimeter observations of the solar-type star
13-277, also known as GM Cep, in the 4 Myr-old cluster Tr 37. GM Cep
experiences rapid magnitude variations of more than 2 mag at optical
wavelengths. We explore the causes of the variability, which seem to be
dominated by strong increases in the accretion, being similar to EX-or
episodes. The star shows high, variable accretion rates (up to ~10
Msun/yr), signs of powerful winds, and it is a very fast rotator (Vsini~43
km/s). Its strong mid-IR excesses reveal a very flared disk and/or a remnant
envelope, most likely out of hydrostatic equilibrium. The 1.3 millimeter fluxes
suggest a relatively massive disk (Mdisk~0.1 Msun). Nevertheless, the
millimeter mass is not enough to sustain increased accretion episodes over
large timescales, unless the mass is underestimated due to significant grain
growth. We finally explore the possibility of GM Cep having a binary companion,
which could trigger disk instabilities producing the enhanced accretion
episodes.Comment: 43 pages, including 10 figures, ApJ in pres
Insights on HydrothermalâMagmatic Interactions and Eruptive Processes at PoĂĄs Volcano (Costa Rica) From HighâFrequency Gas Monitoring and Drone Measurements
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Teacher fabrication as an impediment to professional learning and development: the external mentor antidote
Socioeconomic inequalities in health among Swedish adolescents - adding the subjective perspective
Abstract Background Socioeconomic inequalities in adolescent health predict future inequalities in adult health. Subjective measures of socioeconomic status (SES) may contribute with an increased understanding of these inequalities. The aim of this study was to investigate socioeconomic health inequalities using both a subjective and an objective measure of SES among Swedish adolescents. Method Cross-sectional HBSC-data from 2002 to 2014 was used with a total sample of 23,088 adolescents aged 11â15Â years. Three measures of self-rated health (dependent variables) were assessed: multiple health complaints, life satisfaction and health perception. SES was measured objectively by the Family Affluence Scale (FAS) and subjectively by âperceived family wealthâ (independent variables). The trend for health inequalities was investigated descriptively with independent t-tests and the relationship between independent and dependent variables was investigated with multiple logistic regression analysis. Gender, age and survey year was considered as possible confounders. Results Subjective SES was more strongly related to health outcomes than the objective measure (FAS). Also, the relation between FAS and health was weakened and even reversed (for multiple health complaints) when subjective SES was tested simultaneously in regression models (FAS OR: 1.03, CI: 1.00;1.06 and subjective SES OR: 0.66, CI: 0.63;0.68). Conclusions The level of socioeconomic inequalities in adolescent health varied depending on which measure that was used to define SES. When focusing on adolescents, the subjective appraisals of SES is important to consider because they seem to provide a stronger tool for identifying inequalities in health for this group. This finding is important for policy makers to consider given the persistence of health inequalities in Sweden and other high-income countries
HD 181068: A Red Giant in a Triply-Eclipsing Compact Hierarchical Triple System
Hierarchical triple systems comprise a close binary and a more distant
component. They are important for testing theories of star formation and of
stellar evolution in the presence of nearby companions. We obtained 218 days of
Kepler photometry of HD 181068 (magnitude of 7.1), supplemented by groundbased
spectroscopy and interferometry, which show it to be a hierarchical triple with
two types of mutual eclipses. The primary is a red giant that is in a 45-day
orbit with a pair of red dwarfs in a close 0.9-day orbit. The red giant shows
evidence for tidally-induced oscillations that are driven by the orbital motion
of the close pair. HD 181068 is an ideal target for studies of dynamical
evolution and testing tidal friction theories in hierarchical triple systems.Comment: 22 pages, including supporting on-line material. This is the author's
version of the work. It is posted here by permission of the AAAS for personal
use, not for redistribution. The definitive version was published in Science
Vol. 332 no. 6026 pp. 216-218 (8 April 2011), doi:10.1126/science.1201762.
http://www.sciencemag.org/content/332/6026/216.ful
The New âHidden Abodeâ: Reflections on Value and Labour in the New Economy
In a pivotal section of Capital, volume 1, Marx (1976: 279) notes that, in order to understand the capitalist production of value, we must descend into the âhidden abode of productionâ: the site of the labour process conducted within an employment relationship. In this paper we argue that by remaining wedded to an analysis of labour that is confined to the employment relationship, Labour Process Theory (LPT) has missed a fundamental shift in the location of value production in contemporary capitalism. We examine this shift through the work of Autonomist Marxists like Hardt and Negri, Lazaratto and Arvidsson, who offer theoretical leverage to prize open a new âhidden abodeâ outside employment, for example in the âproduction of organizationâ and in consumption. Although they can open up this new âhidden abodeâ, without LPT's fine-grained analysis of control/resistance, indeterminacy and structured antagonism, these theorists risk succumbing to empirically naive claims about the ânew economyâ. Through developing an expanded conception of a ânew hidden abodeâ of production, the paper demarcates an analytical space in which both LPT and Autonomist Marxism can expand and develop their understanding of labour and value production in today's economy. </jats:p
Sulfur degassing at Erta Ale (Ethiopia) and Masaya (Nicaragua) volcanoes: Implications for degassing processes and oxygen fugacities of basaltic systems
We investigate the relationship between sulfur and oxygen fugacity at Erta Ale and Masaya volcanoes. Oxygen fugacity was assessed utilizing Fe3+/âFe and major element compositions measured in olivineâhosted melt inclusions and matrix glasses. Erta Ale melts have Fe3+/âFe of 0.15â0.16, reflecting fO2 of ÎQFM 0.0â±â0.3, which is indistinguishable from fO2 calculated from CO2/CO ratios in highâtemperature gases. Masaya is more oxidized at ÎQFM +1.7â±â0.4, typical of arc settings. Sulfur isotope compositions of gases and scoria at Erta Ale (ÎŽ34Sgasâââ0.5â°; ÎŽ34Sscoriaâ+â0.9â°) and Masaya (ÎŽ34Sgasâ+â4.8â°; ÎŽ34Sscoriaâ+â7.4â°) reflect distinct sulfur sources, as well as isotopic fractionation during degassing (equilibrium and kinetic fractionation effects). Sulfur speciation in melts plays an important role in isotope fractionation during degassing and S6+/âS is 0.67 in Masaya melt inclusions. No change is observed in Fe3+/âFe or S6+/âS with extent of S degassing at Erta Ale, indicating negligible effect on fO2, and further suggesting that H2S is the dominant gas species exsolved from the S2âârich melt (i.e., no redistribution of electrons). High SO2/H2S observed in Erta Ale gas emissions is due to gas reâequilibration at low pressure and fixed fO2. Sulfur budget considerations indicate that the majority of S injected into the systems is emitted as gas, which is therefore representative of the magmatic S isotope composition. The composition of the Masaya gas plume (+4.8â°) cannot be explained by fractionation effects but rather reflects recycling of high ÎŽ34S oxidized sulfur through the subduction zone
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