Tailoring optical fields emitted by nanometric sources

Here we study a simple way of controlling the emitted fields of sub-wavelength nanometric sources. The system consists of arrays of nanoparticles (NPs) embedded in optical active media. The key concept is the careful tuning of NP's damping factors, which changes the eigenmode's decay rates of the whole array. This, at long time, leads to a locking of relative phases and frequencies of individual localized-surfaces-plasmons (LSPs) and, thus, controlls the emitted field. The amplitude of the LSP's oscillations can be kept constant by embedding the system in optical active media. In the case of full loss compensation, this implies that, not only the relative phases, but also the amplitudes of the LSPs remain fixed, leading us, additionally, to interpret the process as a new example of synchronization. The proposed approach can be used as a general way of controlling and designing the electromagnetic fields emitted by nanometric sources, which can find applications in optoelectronic, nanoscale lithography and probing microscopy

Redox-Active Nanomaterials For Nanomedicine Applications

Nanomedicine utilizes the remarkable properties of nanomaterials for the diagnosis, treatment, and prevention of disease. Many of these nanomaterials have been shown to have robust antioxidative properties, potentially functioning as strong scavengers of reactive oxygen species. Conversely, several nanomaterials have also been shown to promote the generation of reactive oxygen species, which may precipitate the onset of oxidative stress, a state that is thought to contribute to the development of a variety of adverse conditions. As such, the impacts of nanomaterials on biological entities are often associated with and influenced by their specific redox properties. In this review, we overview several classes of nanomaterials that have been or projected to be used across a wide range of biomedical applications, with discussion focusing on their unique redox properties. Nanomaterials examined include iron, cerium, and titanium metal oxide nanoparticles, gold, silver, and selenium nanoparticles, and various nanoscale carbon allotropes such as graphene, carbon nanotubes, fullerenes, and their derivatives/variations. Principal topics of discussion include the chemical mechanisms by which the nanomaterials directly interact with biological entities and the biological cascades that are thus indirectly impacted. Selected case studies highlighting the redox properties of nanomaterials and how they affect biological responses are used to exemplify the biologically-relevant redox mechanisms for each of the described nanomaterials

Chilean Spanish transcultural adaptation of CAP-II and SIR scales in an online format for parents of children with hearing aids or cochlear implants

Spoken language acquisition is challenging for very young deaf or hard-of-hearing children (DHH) who wear hearing aids or cochlear implants (CI). Timely decision-making for treatment is essential for these children and requires suitable assessments. Two such assessments are the Categories of Auditory Performance Index II (CAP-II) and the Speech Intelligibility Rating Scale (SIR). These have been shown to be helpful for the ongoing evaluation of developing speech perception and spoken language skills in various languages, but they are not available in Chilean Spanish. This study aimed to create a Chilean Spanish translation of the CAP-II and SIR appropriate for online self-administration by parents-caregivers in Chile to assist professionals in monitoring DHH children’s progress, considering the COVID-19 restrictions. The methods used in the process started with translating a self-report proposal from the original English versions of the CAP-II and SIR scales. Finally, the Chilean Spanish versions were tested in 107 Chilean parents-caregivers of DHH children with CIs. The results suggest these instruments are suitable for use in a Chilean context

Soft-sediment deformation below mammoth tracks at White Sands National Monument (New Mexico) with implications for biomechanical inferences from tracks

Implicit in any biomechanical analysis of tracks (footprints), whatever the animal, is the assumption that depth distribution within the track reflects the applied plantar pressure in some way. Here we describe sub-track deformation structures produced by Proboscidea (probably Mammuthus columbi) at White Sands National Monument (WHSA) in New Mexico. Patterns of sub-surface deformation are consistent with the plantar pressure data for modern Proboscidea, but do not reflect track morphology. Our work cautions against overinterpreting track topology of any large animal, including extinct animals such as sauropods, in terms of their biomechanics unless the subsurface stratigraphy and associated variation in shear strength is known

Fatigue detection through physiological assessment during real-life occupational situations: Preliminary results

Background: Fatigue is a significant health and safety-related problem among workers. In general, it decreases performance and physical strength, causing incidents and accidents in operational situations. During military activities, soldiers often encounter severe conditions, which combined lead to fatigue manifestations affecting their health and performance. Continuous monitoring of their overall health status would prevent its adverse effects. Objective: This work aimed to present the preliminary results of a retrospective assessment of military training physiological recordings using an alert-based fatigue detection algorithm to validate its accurate functioning. Methods: Three case studies from soldiers participating in military training tests were recruited for evaluation. The referred algorithm was developed to manage fatigue through the combined assessment of physiological variables and determine different fatigue levels warnings to advisetimely interventions and prevent potential health impact. Each examined case included the continuous recording of heart rate, breathing rate and core temperature. The algorithm translated physiological sensory data into minute alarms according to fatigue levels determined through the conjunction of normative and related research criteria. Results and Discussion: Outcomes revealed that the algorithm could evidence the different stages of training and the resulting physical demands on soldiers using their physiological response throughout the exercises. Retrieved fatigue alarms showed the high physiological cost of military practices and helped to overview the impact of each training period. Finally, results also demonstrated the importance of individual and contextualised assessment for accurately characterise the subject's fatigue status. Conclusions: It is concluded that the developed decision model can improve the management of real-time fatigue, allowing early detection of potential indicators of further physical impairments. Furthermore, it can lead to the enhancement of work-rest cycles, not only for tactical personnel but also for any safety-sensitive occupation. For future work, its validity will be tested through more participants, and other variableswill be added to improve its accuracy.</jats:p

CCAT-prime: Science with an Ultra-widefield Submillimeter Observatory at Cerro Chajnantor

We present the detailed science case, and brief descriptions of the telescope design, site, and first light instrument plans for a new ultra-wide field submillimeter observatory, CCAT-prime, that we are constructing at a 5600 m elevation site on Cerro Chajnantor in northern Chile. Our science goals are to study star and galaxy formation from the epoch of reionization to the present, investigate the growth of structure in the Universe, improve the precision of B-mode CMB measurements, and investigate the interstellar medium and star formation in the Galaxy and nearby galaxies through spectroscopic, polarimetric, and broadband surveys at wavelengths from 200 um to 2 mm. These goals are realized with our two first light instruments, a large field-of-view (FoV) bolometer-based imager called Prime-Cam (that has both camera and an imaging spectrometer modules), and a multi-beam submillimeter heterodyne spectrometer, CHAI. CCAT-prime will have very high surface accuracy and very low system emissivity, so that combined with its wide FoV at the unsurpassed CCAT site our telescope/instrumentation combination is ideally suited to pursue this science. The CCAT-prime telescope is being designed and built by Vertex Antennentechnik GmbH. We expect to achieve first light in the spring of 2021.Comment: Presented at SPIE Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy IX, June 14th, 201

Thirty Meter Telescope Site Testing I: Overview

As part of the conceptual and preliminary design processes of the Thirty Meter Telescope (TMT), the TMT site testing team has spent the last five years measuring the atmospheric properties of five candidate mountains in North and South America with an unprecedented array of instrumentation. The site testing period was preceded by several years of analyses selecting the five candidates, Cerros Tolar, Armazones and Tolonchar in northern Chile; San Pedro Martir in Baja California, Mexico and the 13 North (13N) site on Mauna Kea, Hawaii. Site testing was concluded by the selection of two remaining sites for further consideration, Armazones and Mauna Kea 13N. It showed that all five candidates are excellent sites for an extremely large astronomical observatory and that none of the sites stands out as the obvious and only logical choice based on its combined properties. This is the first article in a series discussing the TMT site testing project.Comment: Accepted for publication in PASP, April 2009 issu