Optical coherence tomography angiography of foveal hypoplasia

AIMS: To discuss foveal development in the context of detailed retinal vasculature imaging in foveal hypoplasia using optical coherence tomography angiography. METHODS: In this case series, the optical coherence tomography angiography results of four patients with idiopathic foveal hypoplasia and two patients with foveal hypoplasia secondary to oculocutaneous albinism are presented. RESULTS: Cases with intact visual acuity demonstrated lower grades of foveal hypoplasia on optical coherence tomography, while those with poor vision demonstrated high grades of foveal hypoplasia. The superficial retinal capillary plexus was intact in the foveal area in all cases, with no demonstrable foveal avascular zone. The deep retinal capillary plexus was absent to variable degrees in most cases, but was most persistent in those cases with reduced vision. CONCLUSIONS: The superficial retinal capillary plexus is present in cases with foveal hypoplasia, while the deep retinal capillary plexus is absent to varying degrees. Our findings support the hypothesis that an intact foveal avascular zone of the deep capillary plexus allows for outer retinal photoreceptor specialisation to occur unimpeded, resulting in preserved visual acuity, while this process may be inhibited by an absent deep capillary foveal avascular zone with resultant poor vision

Comparison of ophthalmic training in 6 English-speaking countries

OBJECTIVE: To compare key characteristics of ophthalmology training programs in 6 different English-speaking countries: Australia, New Zealand, Canada, Ireland, the United Kingdom, and the United States. PARTICIPANTS: Seven ophthalmologists with personal knowledge of all 6 systems contributed. METHODS: The main features examined were career pathway, duration of training, surgical training, governing bodies, and examination structure. Data were collected from the literature, online resources, and personal experience. RESULTS: Several differences were highlighted, including length of training (ranging from 4 to 9 years after medical school), number of surgical procedures such as cataracts (ranging from minimum 86 to approximately 600), and structure of fellowship training. CONCLUSIONS: As trainees increasingly seek international experience to enhance their knowledge and skills, the similarities and differences between training programs in different countries have become more relevant. Some of these differences may reflect differing needs of different patient populations and different healthcare delivery systems across the globe. However, these differences should also prompt educators to more carefully scrutinize their own training system and search for potential improvements

Cycle-based Cluster Variational Method for Direct and Inverse Inference

We elaborate on the idea that loop corrections to belief propagation could be dealt with in a systematic way on pairwise Markov random fields, by using the elements of a cycle basis to define region in a generalized belief propagation setting. The region graph is specified in such a way as to avoid dual loops as much as possible, by discarding redundant Lagrange multipliers, in order to facilitate the convergence, while avoiding instabilities associated to minimal factor graph construction. We end up with a two-level algorithm, where a belief propagation algorithm is run alternatively at the level of each cycle and at the inter-region level. The inverse problem of finding the couplings of a Markov random field from empirical covariances can be addressed region wise. It turns out that this can be done efficiently in particular in the Ising context, where fixed point equations can be derived along with a one-parameter log likelihood function to minimize. Numerical experiments confirm the effectiveness of these considerations both for the direct and inverse MRF inference.Comment: 47 pages, 16 figure

The effect of modern intensive monitoring in obstetrics on infant mortality and the incidence of hypoxia and acidosis

Peer Reviewe

Crop type recognition based on Hidden Markov Models of plant phenology

Abstract This work introduces a Hidden Markov Model (HMM) base

One-year outcomes of the ARTISAN-SNM study with the Axonics System for the treatment of urinary urgency incontinence

Aims: Sacral neuromodulation (SNM) is a guideline-recommended treatment for voiding dysfunction including urgency, urge incontinence, and nonobstructive retention as well

Taking the Measure of the Universe: Precision Astrometry with SIM PlanetQuest

Precision astrometry at microarcsecond accuracy has application to a wide range of astrophysical problems. This paper is a study of the science questions that can be addressed using an instrument that delivers parallaxes at about 4 microarcsec on targets as faint as V = 20, differential accuracy of 0.6 microarcsec on bright targets, and with flexible scheduling. The science topics are drawn primarily from the Team Key Projects, selected in 2000, for the Space Interferometry Mission PlanetQuest (SIM PlanetQuest). We use the capabilities of this mission to illustrate the importance of the next level of astrometric precision in modern astrophysics. SIM PlanetQuest is currently in the detailed design phase, having completed all of the enabling technologies needed for the flight instrument in 2005. It will be the first space-based long baseline Michelson interferometer designed for precision astrometry. SIM will contribute strongly to many astronomical fields including stellar and galactic astrophysics, planetary systems around nearby stars, and the study of quasar and AGN nuclei. SIM will search for planets with masses as small as an Earth orbiting in the `habitable zone' around the nearest stars using differential astrometry, and could discover many dozen if Earth-like planets are common. It will be the most capable instrument for detecting planets around young stars, thereby providing insights into how planetary systems are born and how they evolve with time. SIM will observe significant numbers of very high- and low-mass stars, providing stellar masses to 1%, the accuracy needed to challenge physical models. Using precision proper motion measurements, SIM will probe the galactic mass distribution and the formation and evolution of the Galactic halo. (abridged)Comment: 54 pages, 28 figures, uses emulateapj. Submitted to PAS

Congenital rubella syndrome in Iran

BACKGROUND: Congenital rubella syndrome (CRS) can be prevented with appropriate vaccination programs. The prevalence rates of rubella and CRS in Iran are unknown; therefore, the risk of exposure in pregnant women is not clear. The prevalence of CRS in the pre-vaccine period can be estimated by evaluating the proportion of children in the population with sensorineural hearing loss attributable to rubella. METHODS: This was a case-control study to estimate prevalence of CRS in Tehran (Iran) by evaluating the proportion of children with sensorineural hearing loss attributable to rubella. The study used rubella antibody titer as an indicator, and compared the prevalence of rubella antibody between children with and without sensorineural hearing loss. Using these findings, the proportion of cases of sensorineural hearing loss attributable to rubella was estimated. RESULTS: A total of 225 children aged 1 to 4 years were entered into the study (113 cases and 112 controls). There was a significant difference between cases and controls with regard to rubella antibody seropositivity (19.5% vs. 8.9%, respectively, odds ratio = 2.47, 95% CI = 1.04–5.97). The proportion of sensorineural hearing loss cases attributable to rubella was found to be 12%, corresponding to a CRS prevalence of 0.2/1000. CONCLUSION: The prevalence of CRS was approximately 0.2/1000 before rubella vaccination in Iran, Moreover; the results suggest that implementation of appropriate rubella vaccination programs could potentially prevent about 12% of cases of sensorineural hearing loss in Iranian children. This data could potentially be used as baseline data, which in conjunction with an appropriate method, to establish a surveillance system for rubella vaccination in Iran. An appropriate surveillance system is needed, because the introduction of a rubella vaccine without epidemiological data and an adequate monitoring program could result in the shifting of rubella cases to higher ages, and increasing the incidence of CRS