Context.
The conventional approach to direct imaging is to use a single aperture coronagraph with wavefront correction via extreme adaptive optics (AO). Such systems are limited to observing beyond ...an inner working angle (IWA) of a few
λ
/
D.
Nulling interferometry with two or more apertures will enable detections of companions at separations at and beyond the formal diffraction limit.
Aims.
In this paper, we evaluate the astrophysical potential of a kernel-nuller as the prime high-contrast imaging mode of the Very Large Telescope Interferometer (VLTI).
Methods.
By taking into account baseline projection effects induced by Earth rotation, we introduce some diversity in the response of the nuller as a function of time. This response is depicted by transmission maps. We also determine whether we can extract the astrometric parameters of a companion from the kernel outputs, which are the primary intended observable quantities of the kernel-nuller. This then leads us to comment on the characteristics of a possible observing program for the discovery of exoplanets.
Results.
We present transmission maps for both the raw nuller outputs and their subsequent kernel outputs. To further examine the properties of the kernel-nuller, we introduce maps of the absolute value of the kernel output. We also identify 38 targets for the direct detection of exoplanets with a kernel-nuller at the focus of the VLTI.
Conclusions.
With continued upgrades of the VLTI infrastructure, which will reduce fringe tracking residuals, a kernel-nuller would enable the detection of young giant exoplanets at separations <10 AU, where radial velocity and transit methods are more sensitive.
Objectives: To describe ultrasound lesions that may explain male-type infertility. Subjects And Methods: This was a cross-sectional, descriptive study involving 300 men collected between March 2019 ...and March 2022 at the Fertilia medical clinic in Bamako. The study population consisted of consenting male subjects presenting for infertility. All our patients had already undergone a spermogram, they then underwent endorectal and/or suprapubic ultrasound. Results: 300 patients were recruited in our study. The mean age was 37 years, with extremes ranging from 25 to 62 years. 136 patients (45.33%) were aged between 35 and 40. 216 patients (72%) had primary infertility. 267 patients (89%) had a sperm abnormality. 288 patients (96%) had ultrasound abnormalities. The most common pathologies were varicocele (91.66%), prostatic calcifications (3.47%), testicular calcifications (1.38%), seminal vesiculitis (1. 04%), ejaculatory duct calcifications (0.69%), unilateral cryptorchidism (0.69%), differential agenesis (0.69%), anorchidism (0.69%), epididymitis (0.69%). Conclusion:The pressing challenge in the face of male infertility is to establish an etiology in order to satisfy the couples desire to procreate. The spermogram is essential to determine the origin of the infertility, whether male or female. Ultrasound is the technique of choice for diagnosing infertility of testicular or prostato-seminal origin, and must be meticulous and well performed.
The detection and characterization of Earth-like exoplanets around Sun-like stars is a primary science motivation for the Habitable Worlds Observatory. However, the current best technology is not yet ...advanced enough to reach the 10^-10 contrasts at close angular separations and at the same time remain insensitive to low-order aberrations, as would be required to achieve high-contrast imaging of exo-Earths. Photonic technologies could fill this gap, potentially doubling exo-Earth yield. We review current work on photonic coronagraphs and investigate the potential of hybridized designs which combine both classical coronagraph designs and photonic technologies into a single optical system. We present two possible systems. First, a hybrid solution which splits the field of view spatially such that the photonics handle light within the inner working angle and a conventional coronagraph that suppresses starlight outside it. Second, a hybrid solution where the conventional coronagraph and photonics operate in series, complementing each other and thereby loosening requirements on each subsystem. As photonic technologies continue to advance, a hybrid or fully photonic coronagraph holds great potential for future exoplanet imaging from space.
