1,950 research outputs found
Visual outcomes of bilateral congenital and developmental cataracts in young children in south India and causes of poor outcome.
No full textCONTEXT: Bilateral pediatric cataracts are important cause of visual impairment in children. AIM: To study the outcome of bilateral pediatric cataract surgery in young children. SETTING AND DESIGN: Retrospective case series in a tertiary center. MATERIALS AND METHODS: Records of pediatric cataracts operated between January 2001 and December 2003, with a minimum follow-up of 3 months, were reviewed retrospectively. STATISTICAL METHODS: Independent sample t-test, Fisher's exact test, and logistic regression using SPSS (Statistical Package for Social Science, Chicago, USA) version 12. RESULTS: 215/257 (83.7%) patients had a minimum follow-up of 3 months. The mean age of presentation to the hospital was 53 months (range: 0-168 months). Congenital cataract was present in 107 patients (58.2%) and developmental cataract in 77 patients (41.8%). The mean age at surgery was 55.2 months (range: 1-168 months). Out of 430 eyes, 269 (62.6%) had an intraocular lens implanted. The mean duration of follow-up was 13.1 months (range: 3-38 months). Pre-operatively, 102 patients (47.3%) had visual acuity 6/18. The most common early post-operative complication was fibrinous uveitis in 57 eyes (13.3%) and the most common delayed post-operative complication was posterior capsular opacification in 118 eyes (27.4%). The most important prognostic factor for poor outcome was congenital cataract (odds ratio [OR]: 26.3; 95% confidence interval [CI], 4.4-158.5) and total cataract (OR: 4.8; 95% CI, 1.3-17). CONCLUSION: Nearly half of the eyes had visual acuity >6/18. The outcome was poorer in congenital cataracts, especially those operated after >1 year of age
Procedural justice and innovation: Does procedural justice foster innovative behavior?
No full textStreicher B, Jonas E, Maier GW, Frey D. Procedural justice and innovation: Does procedural justice foster innovative behavior? Psychology. 2012;3(12):1100-1103
Merging GW with DMFT and non-local correlations beyond
No full textWe review recent developments in electronic structure calculations that go beyond state-of-the-art methods such as density functional theory (DFT) and dynamical mean field theory (DMFT). Specifically, we discuss the following methods: GW as implemented in the Vienna ab initio simulation package (VASP) with the self energy on the imaginary frequency axis, GW+DMFT, and ab initio dynamical vertex approximation (DΓA). The latter includes the physics of GW, DMFT and non-local correlations beyond, and allows for calculating (quantum) critical exponents. We present results obtained by the three methods with a focus on the benchmark material SrVO3.© The Author(s) 201
A WEAP-MODFLOW surface water-groundwater model for the irrigated Miyandoab plain, Urmia lake basin, Iran: Multi-objective calibration and quantification of historical drought impacts
No full textThis study develops and applies the first coupled surface water-groundwater (SW-GW) flow model for the irrigated Miyandoab plain located in the Urmia basin, in the northwest of Iran. The model is implemented using a dynamic coupling between MODFLOW and WEAP and consists of spatially distributed monthly water balances for the aquifer, root-zone, rivers, canals, and reservoirs. Multi-objective calibration of the model using river discharge and GW level data yields accurate simulation of historical conditions, and results in better constrained parameters compared to using either data source alone. Model simulations show that crop water demand cannot be met during droughts due to limited GW pumping capacity, and that increased GW pumping has a relatively strong impact on GW levels due to the small specific yield of the aquifer. The SW-GW model provides a unique tool for exploring management options that sustain agricultural production and downstream flow to the shrinking Urmia Lake.Accepted author manuscriptWater Resource
Model GW study of the late transition metal monoxides
No full textThe model GW method [F. Gygi and A. Baldereschi, Phys. Rev. Lett. 62, 2160 (1989)] is an efficient simplification to the standard GW approximation which uses model dielectric function to describe the long range Coulomb interactions in semiconductors. In this work, the model GW method is used to calculate the quasiparticle band structures of MnO, FeO, CoO, and NiO. All four late transition metal monoxides are predicted to be insulators. The band gaps, magnetic moments, and quasiparticle spectra are in good agreement with the experiments, except for the satellite structures which are missing in the density of states because the model GW self-energy is static. The high accuracy of model GW is due to the usage of the accurate dielectric constants in the construction of the model dielectric functions which ensures the correct asymptotic behavior of the long range Coulomb interactions. Besides, we find that the transition metal 4s states are irrelevant to the formation of the band gaps, which supports the local approaches and the experimental interpretations of the band gaps by photoemission and electron energy loss spectroscopy, while contradicts the recent calculations by hybrid functionals, exact exchange, and one shot GW approximations. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4758986]Physics, Atomic, Molecular & ChemicalSCI(E)EIPubMed3ARTICLE1515411013
Rab11-FIP3 is a cell cycle-regulated phosphoprotein
No full text<b>BACKGROUND:</b>
Rab11 and its effector molecule, Rab11-FIP3 (FIP3), associate with recycling endosomes and traffic into the furrow and midbody of cells during cytokinesis. FIP3 also controls recycling endosome distribution during interphase. Here, we examine whether phosphorylation of FIP3 is involved in these activities.<p></p>
<b>RESULTS:</b>
We identify four sites of phosphorylation of FIP3 in vivo, S-102, S-280, S-347 and S-450 and identify S-102 as a target for Cdk1-cyclin B in vitro. Of these, we show that S-102 is phosphorylated in metaphase and is dephosphorylated as cells enter telophase. Over-expression of FIP3-S102D increased the frequency of binucleate cells consistent with a role for this phospho-acceptor site in cytokinesis. Mutation of S-280, S-347 or S-450 or other previously identified phospho-acceptor sites (S-488, S-538, S-647 and S-648) was without effect on binucleate cell formation and did not modulate the distribution of FIP3 during the cell cycle. In an attempt to identify a functional role for FIP3 phosphorylation, we report that the change in FIP3 distribution from cytosolic to membrane-associated observed during progression from anaphase to telophase is accompanied by a concomitant dephosphorylation of FIP3. However, the phospho-acceptor sites identified here did not control this change in distribution.<p></p>
<b>CONCLUSIONS:</b>
Our data thus identify FIP3 as a cell cycle regulated phosphoprotein and suggest dephosphorylation of FIP3 accompanies its translocation from the cytosol to membranes during telophase. S102 is dephosphorylated during telophase; mutation of S102 exerts a modest effect on cytokinesis. Finally, we show that de/phosphorylation of the phospho-acceptor sites identified here (S-102, S-280, S-347 and S-450) is not required for the spatial control of recycling endosome distribution or function
Studying the effect of strain induced birefringence on the sensitivity of FBG sensors for Guided wave measurements
No full textTo perform active structural health monitoring (SHM), guided waves (GW) have received great interest as they can inspect large areas with a few sensors and are sensitive to barely-visible structural damages. Fiber Bragg grating (FBG) sensors offer several advantages such as small size, low weight and ability to be embedded but their use has been limited for GW sensing due to their limited sensitivity while using spectrometers. FBG sensors in the edge-filtering configuration have overcome this issue with reasonable sensitivity and there is a renewed interest in their use. It is well known that when subjected to a transverse strain, the circular cross-section of the fiber deforms into an elliptical shape generating the birefringence phenomenon. This deformation, influences the coupling mode of the light inside the FBG and hence, modifies the resulting reflectivity spectrum. This paper investigates how controlled changes in the reflectivity spectrum can be introduced using different transverse loads. The effect of the modified spectrum on the sensitivity of the FBG for GW measurements is then studied. The study also investigates the effect of the transverse strain on the coupling of the GW from the structure into the fiber.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Structural Integrity & Composite
Impact of energy-momentum conservation violation on the configuration of compact stars and their GW echoes
No full textThis work investigates the impacts of energy-momentum conservation violation
on the configuration of strange stars constraint with gravitational wave (GW)
event GW190814 as well as eight recent observations of compact objects. The GW
echoes from these interesting classes of compact objects are also calculated.
To describe the matter of strange stars, we have used two different equations
of state (EoSs): first an ad-hoc exotic EoS, the stiffer MIT Bag model and next
realistic CFL phase of quark matter EoS. We choose Rastall gravity as a simple
model with energy-momentum conservation violation with a set of model parameter
values. Our results show that this gravity theory permits stable solutions of
strange stars and the resulting structures can foster GW echoes. We illustrate
the implication of the gravity theory and found that the negative values of the
Rastall parameter result in more compact stellar configurations and lower GW
echo frequency. With an increase in the Rastall parameter, both the compactness
of the stellar configurations and echo time decrease. It is worth mentioning
here that with the chosen set of some probable strange star candidates from
observational data and also in light of GW 190814, we have evaluated the radii
of stellar models. Also, the GW echo frequencies associated with strange stars
are found to be in the range of { kHz} for both cases. {From this
work, it is also inferred that the assumption regarding the equivalence of
Rastall's theory to Einstein's theory is refuted as we have noticed many
deviations in the physical properties of the considered compact stars.Comment: 8 figures and 4 table
EMT Real-Time Simulation Model of a 2 GW Offshore Renewable Energy Hub Integrating Electrolysers
No full textDue to their weak nature, such as low inertia, offshore energy hubs are prone to unprecedented fast dynamic phenomena. This can lead to undesired instability problems. Recent literature, with main focus on onshore systems, suggests that electrolysers could be an attractive option to support wind generators in the mitigation of balancing problems. This paper presents an Electromagnetic Transient (EMT) model for real-time simulation based study of the dynamics of active power and voltage responses of offshore hubs due to wind speed fluctuations. The purpose of this study was to ascertain the ability of an electrolyser to support an offshore energy hub under different scenarios and with different locations of the electrolyser. Two locations of Proton Exchange Membrane (PEM) electrolysers were considered: centralised (at the AC common bus of the hub) or distributed (at the DC link of the wind turbines). Numerical simulations conducted in RSCAD® on a 2 GW offshore hub with 4 × 500 MW wind power plants and 330 or 600 MW PEM electrolysers show that electrolysers can effectively support the mitigation of sudden wind speed variations, irrespective of the location. The distributed location of electrolysers can be beneficial to prevent large spillage of wind power generation during the isolation of faults within the hub.Intelligent Electrical Power Grid
Electronic properties of lanthanide oxides from the GW perspective
No full textA first-principles understanding of the electronic properties of f-electron systems is currently regarded as a great challenge in condensed-matter physics because of the difficulty in treating both localized and itinerant states on the same footing by the current theoretical approaches, most notably density-functional theory (DFT) in the local-density or generalized gradient approximation (LDA/GGA). Lanthanide sesquioxides (Ln(2)O(3)) are typical f-electron systems for which the highly localized f states play an important role in determining their chemical and physical properties. In this paper, we present a systematic investigation of the performance of many-body perturbation theory in the GW approach for the electronic structure of the whole Ln(2)O(3) series. To overcome the major failure of LDA/GGA, the traditional starting point for GW, for f-electron systems, we base our GW calculations on Hubbard U corrected LDA calculations (LDA + U). The influence of the crystal structure, the magnetic ordering, and the existence of metastable states on the electronic band structures are studied at both the LDA + U and the GW level. The evolution of the band structure with increasing number of f electrons is shown to be the origin for the characteristic structure of the band gap across the lanthanide sesquioxide series. A comparison is then made to dynamical mean-field theory (DMFT) combined with LDA or hybrid functionals to elucidate the pros and cons of these different approaches.Physics, Condensed MatterSCI(E)22ARTICLE12null8
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