935 research outputs found

    Alignment in total knee arthroplasty : what’s in a name?

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    Dissatisfaction following total knee arthroplasty is a well-documented phenomenon. Although many factors have been implicated, including modifiable and nonmodifiable patient factors, emphasis over the past decade has been on implant alignment and stability as both a cause of, and a solution to, this problem. Several alignment targets have evolved with a proliferation of techniques following the introduction of computer and robotic-assisted surgery. Mechanical alignment targets may achieve mechanically-sound alignment while ignoring the soft tissue envelope; kinematic alignment respects the soft tissue envelope while ignoring the mechanical environment. Functional alignment is proposed as a hybrid technique to allow mechanically-sound, soft tissue-friendly alignment targets to be identified and achieved

    Work-Integrated and Cooperative Learning Effects on Micro-Electronics Design Classes

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    Cooperative learning and work-integrated learning are the latest trends in information delivery at high schools and universities. In cooperative learning, teachers organize students' interactions and educate them to work in small groups to enhance each other's learning. Whereas, work-integrated learning, is a type of experiential learning that allows students to participate in real-world work during their studies. Both approaches help bridge the gap between theoretical knowledge gained from classrooms and professional market needs. Electrical engineering is a field that could highly benefit from such a scheme. Having to be continuously up-to-date with the latest advances in the field of micro-electronics is difficult. Consequently, Several challenges are imposed on faculty members and academics who teach micro-electronics circuit design courses in electrical engineering for senior undergraduate or graduate students. This paper presents a case study of the apparent benefits and effectiveness of cooperative learning and work-integrated learning in the Electronics II and VLSI classes offered at a university. Furthermore, it aids programs in electrical engineering to meet ABET students' outcome (4)

    Relationships between the AE, ap and Dst indices near solar minimum (1974) and at solar maximum (1979)

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    International audienceThree-hourly average values of the Dst, AE and ap geomagnetic activity indices have been studied for 1 year's duration near the solar minimum (1974) and also at the solar maximum (1979). In 1979 seven intense geomagnetic storms (Dst <?100 nT) occurred, whereas in 1974 only three were reported. This study reveals: (1) the yearly average of AE is greater in 1974 than in 1979, whereas the inverse seems to be true for the yearly average of Dst, when a higher number of intense storms is present. These averages indicate the kind of activity occurring on the sun as shown in earlier work. (2) The seasonal variation of Dst is higher than that of ap and is almost negligible in AE. (3) The correlation coefficient of ap × AE is in general the highest, as the magnetometers that monitor both indices are close, and is surpassed only by the ap × Dst correlation during geomagnetic storms, when the influence of the ring current is dominant. The correlation of ap × Dst also shows a seasonal variability. (4) For the first time a study of correlation between ap and a linear combination of AE and Dst has also been made. We found higher correlation coefficients in this case as compared to those between ap × Dst and ap × AE

    Perception and intentions to quit among waterpipe smokers in Qatar: a cross-sectional survey

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    Objective: To evaluate the perceptions and attitudes of waterpipe (shisha) smokers in Qatar regarding the health risks associated with addiction and to determine their intentions to quit. Methods: A cross-sectional survey was conducted among 181 self-reported waterpipe smokers. Participants were approached in public places as well as in shisha cafes in Qatar. The questionnaire included items related to perception, attitude and intention to quit. Both descriptive and inferential statistics were performed for data analyses, with P ≤ 0.05 considered statistically significant. Results: About 44% of the respondents believed that waterpipe smoking was safer than cigarette smoking, and more than 70% would not mind if their children became involved in waterpipe smoking. More than half of the current smokers wanted to quit smoking shisha at some point, and 17% identified health concerns as the main motivating factor for their intention to quit. Conclusion: A large proportion of shisha smokers viewed shisha as a safer alternative to cigarettes, yet they admitted to intending to quit. These findings underscore the need to design educational interventions and awareness campaigns as well as impose stringent laws on waterpipe smoking in public places in Qatar.Undergraduate Research Experience Program (UREP) grant (UREP 13-063-3-016) from the Qatar National Research Fund (a member of the Qatar Foundation)

    Design of sub-Angstrom compact free-electron laser source

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    In this paper, we propose for first time practical parameters to construct a compact sub-Angstrom Free Electron Laser (FEL) based on Compton backscattering. Our recipe is based on using picocoulomb electron bunch, enabling very low emittance and ultracold electron beam. We assume the FEL is operating in a quantum regime of Self Amplified Spontaneous Emission (SASE). The fundamental quantum feature is a significantly narrower spectrum of the emitted radiation relative to classical SASE. The quantum regime of the SASE FEL is reached when the momentum spread of the electron beam is smaller than the photon recoil momentum. Following the formulae describing SASE FEL operation, realistic designs for quantum FEL experiments are proposed. We discuss the practical constraints that influence the experimental parameters. Numerical simulations of power spectra and intensities are presented and attractive radiation characteristics such as high flux, narrow linewidth, and short pulse structure are demonstrated

    Changes of Sand Fly Populations and Leishmania infantum Infection Rates in an Irrigated Village Located in Arid Central Tunisia

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    Citation: Barhoumi, W., Fares, W., Cherni, S., Derbali, M., Dachraoui, K., Chelbi, I., . . . Zhioua, E. (2016). Changes of Sand Fly Populations and Leishmania infantum Infection Rates in an Irrigated Village Located in Arid Central Tunisia. International Journal of Environmental Research and Public Health, 13(3), 10. doi:10.3390/ijerph13030329The current spread of zoonotic visceral leishmaniasis (ZVL) throughout arid areas of Central Tunisia is a major public health concern. The main objective of this study is to investigate whether the development of irrigation in arid bio-geographical areas in Central Tunisia have led to the establishment of a stable cycle involving sand flies of the subgenus Larroussius and Leishmania infantum, and subsequently to the emergence of ZVL. Sand flies were collected from the village of Saddaguia, a highly irrigated zone located within an arid bio-geographical area of Central Tunisia by using modified Centers for Diseases Control (CDC) light traps. Morphological keys were used to identify sand flies. Collected sand flies were pooled with up to 30 specimens per pool according to date and tested by nested Polymerase Chain Reaction (PCR) DNA sequencing from positive pools was used to identify Leishmania spp. A total of 4915 sand flies (2422 females and 2493 males) were collected from Saddaguia in September and in October 2014. Morphological identification confirmed sand flies of the subgenus Larroussius to be predominant. PCR analysis followed by DNA sequencing indicated that 15 pools were infected with L. infantum yielding an overall infection rate of 0.6%. The majority of the infected pools were of sand fly species belonging to subgenus Larroussius. Intense irrigation applied to the arid bio-geographical areas in Central Tunisia is at the origin of the development of an environment capable of sustaining important populations of sand flies of the subgenus Larroussius. This has led to the establishment of stable transmission cycles of L. infantum and subsequently to the emergence of ZVL

    HD 46375: seismic and spectropolarimetric analysis of a young Sun hosting a Saturn-like planet

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    HD 46375 is known to host a Saturn-like exoplanet orbiting at 0.04 AU from its host star. Stellar light reflected by the planet was tentatively identified in the 34-day CoRoT run acquired in October-November 2008. We constrain the properties of the magnetic field of HD 46375 based on spectropolarimetric observations with the NARVAL spectrograph at the Pic du Midi observatory. In addition, we use a high-resolution NARVAL flux spectrum to contrain the atmospheric parameters. With these constraints, we perform an asteroseismic analysis and modelling of HD 46375 using the frequencies extracted from the CoRoT light curve. We used Zeeman Doppler imaging to reconstruct the magnetic map of the stellar surface. In the spectroscopic analysis we fitted isolated lines using 1D LTE atmosphere models. This analysis was used to constrain the effective temperature, surface gravity, and chemical composition of the star. To extract information about the p-mode oscillations, we used a technique based on the envelope autocorrelation function (EACF). From the Zeeman Doppler imaging observations, we observe a magnetic field of ~5 gauss. From the spectral analysis, HD 46375 is inferred to be an unevolved K0 type star with high metallicity [Fe/H]=+0.39. Owing to the relative faintness of the star (m_hip=8.05), the signal-to-noise ratio is too low to identify individual modes. However, we measure the p-mode excess power and large separation Delta nu_0=153.0 +/- 0.7 muHz. We are able do constrain the fundamental parameters of the star thanks to spectrometric and seismic analyses. We conclude that HD 46375 is similar to a young version of Alpha-CenB. This work is of special interest because of its combination of exoplanetary science and asteroseismology, which are the subjects of the current Kepler mission and the proposed PLATO mission.Comment: Accepted in Astronomy & Astrophysics. 8 pages, 9 figure

    Biased signaling of lipids and allosteric actions of synthetic molecules for GPR119

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    AbstractGPR119 is a Gαs-coupled lipid-sensor in the gut, where it mediates release of incretin hormones from the enteroendocrine cells and in pancreatic α-cells, where it releases insulin. Naturally occurring lipids such as monoacylglycerols (MAGs) and N-acylethanolamines (NAEs), like oleoylethanolamide (OEA), activate GPR119, and multiple synthetic ligands have been described. Here, we extend the GPR119 signaling profile to Gαq and Gαi in addition to β-arrestin recruitment and the downstream transcription factors CRE (cAMP response element), SRE (serum response element) and NFAT (nuclear factor of activated T cells). The endogenous OEA and the synthetic AR231453 were full agonists in all pathways except for NFAT, where no ligand-modulation was observed. The potency of AR231453 varied <16-fold (EC50 from 6 to 95nM) across the different signaling pathways, whereas that of OEA varied >175-fold (from 85nM to 15μM) indicating a biased signaling for OEA. The degree of constitutive activity was 1–10%, 10–30% and 30–70% of OEA-induced Emax in Gαi, Gαq and Gαs-driven pathways, respectively. This coincided with the lowest and highest OEA potency observed in Gαi and Gαs-driven pathways, respectively. Incubation for 2h with the 2-MAG-lipase inhibitor JZL84 doubled the constitutive activity, indicating that endogenous lipids contribute to the apparent constitutive activity. Finally, besides being an agonist, AR231453 acted as a positive allosteric modulator of OEA and increased its potency by 54-fold at 100nM AR231453. Our studies uncovering broad and biased signaling, masked constitutive activity by endogenous MAGs, and ago-allosteric properties of synthetic ligands may explain why many GPR119 drug-discovery programs have failed so far

    Synthetic ozone deposition and stomatal uptake at flux tower sites

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    We develop and evaluate a method to estimate O-3 deposition and stomatal O-3 uptake across networks of eddy covariance flux tower sites where O-3 concentrations and O-3 fluxes have not been measured. The method combines standard micrometeorological flux measurements, which constrain O-3 deposition velocity and stomatal conductance, with a gridded dataset of observed surface O-3 concentrations. Measurement errors are propagated through all calculations to quantify O-3 flux uncertainties. We evaluate the method at three sites with O(3 )flux measurements: Harvard Forest, Blodgett Forest, and Hyytiala Forest. The method reproduces 83 % or more of the variability in daily stomatal uptake at these sites with modest mean bias (21 % or less). At least 95 % of daily average values agree with measurements within a factor of 2 and, according to the error analysis, the residual differences from measured O-3 fluxes are consistent with the uncertainty in the underlying measurements. The product, called synthetic O-3 flux or SynFlux, includes 43 FLUXNET sites in the United States and 60 sites in Europe, totaling 926 site years of data. This dataset, which is now public, dramatically expands the number and types of sites where O-3 fluxes can be used for ecosystem impact studies and evaluation of air quality and climate models. Across these sites, the mean stomatal conductance and O-3 deposition velocity is 0.03-1.0 cm s(-1). The stomatal O-3 flux during the growing season (typically April-September) is 0.5-11.0 nmol O-3 m(-2) s(-1) with a mean of 4.5 nmol O(3 )m(-2) s(-1) and the largest fluxes generally occur where stomatal conductance is high, rather than where O-3 concentrations are high. The conductance differences across sites can be explained by atmospheric humidity, soil moisture, vegetation type, irrigation, and land management. These stomatal fluxes suggest that ambient O-3 degrades biomass production and CO2 sequestration by 20 %-24 % at crop sites, 6 %-29 % at deciduous broadleaf forests, and 4 %-20 % at evergreen needleleaf forests in the United States and Europe.Peer reviewe
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