928 research outputs found
In search of virus carriers of the 1988 and 2002 phocine distemper virus outbreaks in European harbour seals
European harbour seal (Phoca vitulina) populations decreased substantially during the phocine distemper virus (PDV) outbreaks of 1988 and 2002. Different hypotheses have stated that various seals and terrestrial carnivore species might be the source of infection. To further analyse these hypotheses, grey (Halichoerus grypus) and ringed (Phoca hispida) seals, polar bears (Ursus maritimus) and minks (Mustela lutreola) were sampled from the North Sea and East Greenland coasts between 1988 and 2004 and investigated by RT-PCR using a panmorbillivirus primer pair. However, all samples were negative for morbillivirus nucleic acid
Scientific Reference Datasets - Cornerstones of Reproducible Research::Design, Test & Distribution using R
Scientific Reference Datasets - Cornerstones of Reproducible Research::Design, Test & Distribution using R
A 180 ka record of environmental change at Erdut (Croatia): a new chronology for the loessâpalaeosol sequence and its implications for environmental interpretation
While there are numerous thick loessâpalaeosol sequences preserved across the Carpathian Basin, well dated sites that provide terrestrial palaeoenvironmental records extending beyond last glacialâinterglacial cycle are scarce. Robust chronologies are essential for correlations of loess with other longâterm Quaternary records and to further understanding of the palaeoenvironment and climate of this important region beyond the last 125 ka. Here a new geochronology based on 13 postâinfrared infrared stimulated luminescence ages focused on the lower part of the loessâpalaeosol sequence at Erdut is presented. The results show that the lower part of the Erdut profile spans the penultimate glacial cycle (MIS 7 to MIS 5). The considerable sediments overlaying the investigated part of the profile suggest that this section spans two glacial cycles, rather than the previously suggested one. The most likely source of the discrepancy is the use of uncorrected infrared stimulated luminescence signal, which can cause age underestimation if not accounted for. This study demonstrates the need to revisit sites such as Erdut, reâdate them using updated measurement protocols, and update existing palaeoenvironmental interpretations
The heavy quark decomposition of the S-matrix and its relation to the pinch technique
We propose a decomposition of the S-matrix into individually gauge invariant
sub-amplitudes, which are kinematically akin to propagators, vertices, boxes,
etc. This decompsition is obtained by considering limits of the S-matrix when
some or all of the external particles have masses larger than any other
physical scale. We show at the one-loop level that the effective gluon
self-energy so defined is physically equivalent to the corresponding gauge
independent self-energy obtained in the framework of the pinch technique. The
generalization of this procedure to arbitrary gluonic -point functions is
briefly discussed.Comment: 11 uuencoded pages, NYU-TH-94/10/0
3D Heads-Up Display vs. Standard Operating Microscope Vitrectomy for Rhegmatogenous Retinal Detachment
Purpose: To assess the efficacy and outcomes of 23-gauge vitreoretinal surgery for rhegmatogenous retinal detachment using a three-dimensional heads-up display (3D HUD) surgical platform as compared to a standard operating microscope (SOM) setting. Design: Retrospective cohort study. Participants: One hundred and forty consecutive eyes of 140 patients with primary retinal detachment. Methods: All eyes underwent 23-gauge pars plana vitrectomy for primary retinal detachment using either a 3D HUD (NGENUITY;Alcon Inc., Fort Worth, Texas, USA;n = 70 eyes) or a SOM setting (n = 70 eyes);in cases of significant cataract, additional phacoemulsification with intraocular lens (IOL) implantation was performed. Minimum follow-up was 2 months. Main Outcome Measures: Primary retinal reattachment rate, rate of proliferative vitreoretinopathy (PVR), best-corrected visual acuity (BCVA), and duration of surgery. Results: There were 70 eyes each in the 3D HUD and the SOM group. Both groups did not differ concerning age (p = 0.70), extent of retinal detachment (p = 0.07), number of retinal tears (p = 0.40), macular involvement (p = 0.99), and preoperative BCVA (p = 0.99). Postoperatively, 3D HUD and SOM were comparable concerning the primary retinal reattachment rate (88.6 vs. 94.3%;p = 0.37), the development of postoperative PVR (12.9% vs. 7.1%;p = 0.40) and final BCVA (0.26 +/- 0.40 vs. 0.21 +/- 0.38 logMAR;p = 0.99). Duration of surgery was significantly longer in the 3D HUD group (66.2 +/- 16.5 vs. 61.2 +/- 17.1 min;p = 0.04), an effect which however vanished after a "learning curve" of the first 35 eyes (p = 0.49). Conclusions: On par results to a conventional operating microscope can be achieved with a 3D HUD setting when performing 23-gauge vitreoretinal surgery for rhegmatogenous retinal detachment, including the primary retinal reattachment rate, the incidence of postoperative PVR and final BCVA. However, duration of surgery might initially be slightly longer with 3D HUD, suggesting the effect of a learning curve
Intraocular Lens Power Calculation after Small Incision Lenticule Extraction
With more than 1.5 million Small Incision Lenticule Extraction (SMILE) procedures having already been performed worldwide in an ageing population, intraocular lens (IOL) power calculation in post-SMILE eyes will inevitably become a common challenge for ophthalmologists. Since no refractive outcomes of cataract surgery following SMILE have been published, there is a lack of empirical data for optimizing IOL power calculation. Using the ray tracing as the standard of reference - a purely physical method that obviates the need for any empirical optimization - we analyzed the agreement of various IOL power calculation formulas derived from the American Society of Cataract and Refractive Surgeons (ASCRS) post-keratorefractive surgery online calculator. In our study of 88 post-SMILE eyes, the Masket formula showed the smallest mean prediction error [-0.36 +/- 0.32 diopters (D)] and median absolute error (0.33D) and yielded the largest percentage of eyes within +/- 0.50D (70%) in reference to ray tracing. Non-inferior refractive prediction errors and +/- 0.50D accuracies were achieved by the Barrett True K, Barrett True K No History and the Potvin-Hill formula. Use of these formulas in conjunction with ray tracing is recommended until sufficient data for empirical optimization of IOL power calculation after SMILE is available
Vanishing pachy-choroid in pachychoroid neovasculopathy under long-term anti-vascular endothelial growth factor therapy
BACKGROUND To investigate the diagnostic value of choroidal thickness in the definition of pachychoroid neovasculopathy (PNV), especially in eyes treated with anti-vascular endothelial growth factor (VEGF) therapy. METHODS Twenty-two consecutive eyes of 11 patients with uni- or bilateral PNV were analyzed. Anti-VEGF treatment was correlated with changes in choroidal thickness on enhanced depth imaging optical coherence tomography. RESULTS There were 14 eyes with PNV and 8 non-neovascular partner eyes. Mean age was 64.2 ± 4.0 (range: 60-72), total follow-up was 1.8 ± 0.4 (1-2) years. In PNV eyes, choroidal thickness at baseline was 400 ± 58 (269-485) ÎŒm. After two years and 13 anti-VEGF injections on average, a mean reduction of - 39 ± 10 (- 26 to - 56) % to final 241 ± 52 (162-327) ÎŒm was observed (p~ 0.13 for all comparisons). A significant correlation of choroidal thinning and anti-VEGF injection rate was observed at year one (r = - 0.79; R2~= 0.63; p~= 0.00073) and two (r = - 0.69; R2~= 0.48; p~= 0.019). While 85.7% of PNV eyes exceeded a pachychoroid threshold of â„350 ÎŒm at baseline, this figure dropped to 21.4% at year one and 0% at year two. CONCLUSION In PNV, choroidal thickness significantly decreases with anti-VEGF therapy, resembling a \textquotedblvanishing pachy-choroid\textquotedbl, and thus does not represent a valid long-term diagnostic criterium, especially when differentiating PNV from nAMD
Dilution of the magnetic lattice in the Kitaev candidate α-RuCl<sub>3</sub> by Rh<sup>3+</sup> doping
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