Wavefront sensing with a brightest pixel selection algorithm

Astronomical adaptive optics systems with open-loop deformable mirror control have recently come on-line. In these systems, the deformable mirror surface is not included in the wavefront sensor paths, and so changes made to the deformable mirror are not fed back to the wavefront sensors. This gives rise to all sorts of linearity and control issues mainly centred on one question: Has the mirror taken the shape requested? Non-linearities in wavefront measurement and in the deformable mirror shape can lead to significant deviations in mirror shape from the requested shape. Here, wavefront sensor measurements made using a brightest pixel selection method are discussed along with the implications that this has for open-loop AO systems. Discussion includes elongated laser guide star spots and also computational efficiency.Comment: 10 pages, 12 figures, accepted by MNRA

Review and optimization of housing and husbandry of anemonefishes for use in research

As anemonefishes of the genus Amphiprion are emerging as a model organism for marine science, it is critical to have standardization in housing and husbandry protocols for research laboratories. Here, we conducted a literature review, a questionnaire survey, and two experiments regarding the housing and husbandry of anemonefishes for use in research. The literature review identified the need for standardization and optimization of multiple variables including tank volume, diet composition, and lighting type for the housing of broodstock pairs. The questionnaire survey was completed by 27 laboratories, with a 45% response rate, across 11 different countries in Europe, North America, Asia, and Australia. Results from the survey confirmed the need for standardization or optimization of laboratory protocols. The experimental manipulation of housing of Amphiprion percula was conducted over a 3-month period, where reproduction was monitored for 8 breeding pairs housed in large, 120-liter (30-gallon) tanks versus 7 breeding pairs housed in small, 9-liter (2-gallon) tanks. Results suggest that reproductive output was significantly reduced among breeding pairs in experimental 9-liter tanks when compared to those housed in standard 120-liter tanks. The experimental manipulation of husbandry of A. percula was conducted over a 3-month period, where reproduction was monitored across 19 breeding pairs on a high ration diet (1 mL scoop of pellets) versus 15 breeding pairs on a low ration diet (0.5 mL scoop of pellets). Results suggest that reproductive output was significantly reduced among breeding pairs on a low ration diet when compared to those on a high ration diet. Although the experimental 9-liter tanks were likely below the optimum for reproductive output, the fact that reproduction still occurred suggests that the fish will reproduce in tanks smaller than 120 liters and that 20-75 liter tanks may be the best option for housing large numbers of A. percula and similar species. The reproductive output of broodstock pairs fed a high ration diet is similar to that seen in the wild, and provision of higher quality foods (e.g., cuttlefish, shrimp, fish eggs, etc.) beyond commercial pellets may enhance survival of larvae. In conclusion, our research suggests that the anemonefish research community should be discussing the optimization and standardization of housing and husbandry or, minimally, recognize that housing and husbandry influence a wide range of traits and will influence the results and conclusions drawn from experiments

An aperture masking mode for the MICADO instrument

MICADO is a near-IR camera for the Europea ELT, featuring an extended field (75" diameter) for imaging, and also spectrographic and high contrast imaging capabilities. It has been chosen by ESO as one of the two first-light instruments. Although it is ultimately aimed at being fed by the MCAO module called MAORY, MICADO will come with an internal SCAO system that will be complementary to it and will deliver a high performance on axis correction, suitable for coronagraphic and pupil masking applications. The basis of the pupil masking approach is to ensure the stability of the optical transfer function, even in the case of residual errors after AO correction (due to non common path errors and quasi-static aberrations). Preliminary designs of pupil masks are presented. Trade-offs and technical choices, especially regarding redundancy and pupil tracking, are explained.Comment: SPIE 2014 Proceeding -- Montrea

Artists’ Studio Archives Managing Your Studio Practice & Building a Creative Legacy Revised Edition (2022): A Comprehensive Guide for Artists & Their Assistants

This guide is based on real-life scenarios and best practices in managing an art studio archive. It will aid artists in every career stage, from emerging artists to late-career artists; the yet-to- be-discovered and the well-established. Increasing productivity in the studio with good documentation helps artists better prepare to sell work and secure grant funding, as well as manage better the legal and financial aspects of an artistic practice

Artist\u27 Studio Archives: Managing Personal Collections & Creative Legacies

A guide for artists, their assistants, and others managing and preserving an artist\u27s studio archives

Magnetic and electronic properties of lithium cobalt oxide substituted by nickel

[Abstract] We measured susceptibility, electron-spin resonance, magnetization and electrical conductivity of LiCo1−yNiyO2 powders synthesized by wet-chemistry method using succinic acid as chelating agent. We found unusual properties in the nickel-rich LiCo0.2Ni0.8O2, which shows several resonance lines as a function of the temperature in the range 3.5–300 K. The signal at low magnetic field is attributed to the magnetic domains in the nanostructured sample. The two other lines correspond to the typical ferromagnetic signal observed in powdered compounds. In the temperature range 120–300 K, the unique ESR line centered at 315 mT is the paramagnetic signal with a gyromagnetic factor g=2.12, which is in good agreement with the presence of a high concentration of Ni3+ (3d7) ions. In the nickel-rich oxide, LiNi0.8Co0.2O2, the magnetic data are qualitatively well-described by the model proposed by Drillon and Panissod for a 3D ferromagnetic order.Spanish and French Foreign Office; HF 1999-0101Spanish and French Foreign Office; PAI Picasso 00717T

Ultimate performance of Quantum Well Infrared Photodetectors in the tunneling regime

Thanks to their wavelength diversity and to their excellent uniformity, Quantum Well Infrared Photodetectors (QWIP) emerge as potential candidates for astronomical or defense applications in the very long wavelength infrared (VLWIR) spectral domain. However, these applications deal with very low backgrounds and are very stringent on dark current requirements. In this paper, we present the full electro-optical characterization of a 15 micrometer QWIP, with emphasis on the dark current measurements. Data exhibit striking features, such as a plateau regime in the IV curves at low temperature (4 to 25 K). We show that present theories fail to describe this phenomenon and establish the need for a fully microscopic approach

The Center of Excellence Model for Information Services (CLIR pub 163)

In 2013, The Andrew W. Mellon Foundation awarded a group of librarians from ARL\u27s Research Library Leadership Fellows program a planning grant to examine the center of excellence (CoE) model for information services. Used in a variety of industries, CoEs are designed to attract the most talented researchers in a particular field, enhance collaboration, and improve access to the resources needed for their research. The planning grant was awarded to determine whether the CoE model could serve as a means to provide the new services required for the effective use of digital information. This report describes the team\u27s approach to examining the feasibility of CoEs in the library setting. The team conducted preliminary investigations of more than 100 centers, which they narrowed to 35 for in-depth research. Interviews were conducted with staff at 19 centers and 7 funding organizations. In their conclusion, the team advises developing networks of expertise or expert networks, instead of CoEs, and provides a series of recommendations for building such networks

Ex vivo characterization of neuroinflammatory and neuroreceptor changes during epileptogenesis using candidate positron emission tomography biomarkers

Objective: Identification of patients at risk of developing epilepsy before the first spontaneous seizure may promote the development of preventive treatment providing opportunity to stop or slow down the disease. // Methods: As development of novel radiotracers and on‐site setup of existing radiotracers is highly time‐consuming and expensive, we used dual‐centre in vitro autoradiography as an approach to characterize the potential of innovative radiotracers in the context of epilepsy development. Using brain slices from the same group of rats, we aimed to characterise the evolution of neuroinflammation and expression of inhibitory and excitatory neuroreceptors during epileptogenesis using translational positron emission tomography (PET) tracers; 18F‐flumazenil (18F‐FMZ; GABAA receptor), 18F‐FPEB (metabotropic glutamate receptor 5; mGluR5), 18F‐flutriciclamide (translocator protein; TSPO, microglia activation) and 18F‐deprenyl (monoamine oxidase B, astroglia activation). Autoradiography images from selected time points after pilocarpine‐induced status epilepticus (SE; baseline, 24 and 48 hours, 5, 10 and 15 days and 6 and 12‐14 weeks after SE) were normalized to a calibration curve, co‐registered to an MRI‐based 2D region‐of‐interest atlas, and activity concentration (Bq/mm2) was calculated. // Results: In epileptogenesis‐associated brain regions, 18F‐FMZ and 18F‐FPEB showed an early decrease after SE. 18F‐FMZ decrease was maintained in the latent phase and further reduced in the chronic epileptic animals, while 18F‐FPEB signal recovered from day 10, reaching baseline levels in chronic epilepsy. 18F‐flutriciclamide showed an increase of activated microglia at 24 hours after SE, peaking at 5‐15 days and decreasing during the chronic phase. On the other hand, 18F‐deprenyl autoradiography showed late astrogliosis, peaking in the chronic phase. // Significance: Autoradiography revealed different evolution of the selected targets during epileptogenesis. Our results suggest an advantage of combined imaging of inter‐related targets like glutamate and GABAA receptors, or microglia and astrocyte activation, in order to identify important interactions, especially when using PET imaging for the evaluation of novel treatments