TolTEC: A New Multichroic Imaging Polarimeter for the Large Millimeter Telescope

The TolTEC camera is a new millimeter-wave imaging polarimeter designed to fill the focal plane of the 50-m diameter Large Millimeter Telescope (LMT). Combined with the LMT, TolTEC offers high angular resolution (5 , 6.3 , 9.5 ) for simultaneous, polarization-sensitive observations in its three wavelength bands: 1.1, 1.4, and 2.0 mm. Additionally, TolTEC is designed to reach groundbreaking mapping speeds in excess of 1 deg2/mJy2/hr, which will enable the completion of deep surveys of large-scale structure, galaxy evolution, and star formation that are currently limited when considering practical observation times for other ground-based observatories. This thesis covers the design as well as the in-lab and LMT characterization of the instrument. Chapter 2 covers TolTEC\u27s design overview and describes each subsystem (cryogenics, optics, detectors, and detector readout). Chapter 3 examines the performance of each subsystem prior to installation at the LMT. In particular, this chapter provides the instrument\u27s responsivity, efficiency, beam response, and readout noise while testing at UMass Amherst. The following chapter covers the initial results from commissioning at the LMT between December 2022 and April 2023. Based on the in-lab testing and LMT commissioning, I provide a number of procedures for operating/repairing the instrument in the appendices. I conclude Chapter 5 with the development of a new pilot study to leverage TolTEC\u27s high resolution and sensitivity with the goal of exploring galaxy cluster thermodynamics across cosmic time. While TolTEC observations of galaxy clusters were not available for this thesis, I describe the analysis pipeline I developed to perform a power spectrum analysis on intracluster medium (ICM) pressure fluctuations. The result of this pipeline is a power spectrum that can be analyzed to extract information on the thermodynamic state of the ICM. This type of study has only been performed on two clusters as of 2023, thus with TolTEC\u27s mapping speed and sensitivity we will be able to expand this study and create the largest sample of its kind

The Role of Language in the Development of Temporal Cognition in 6- to 10-Year-Old Children

The ability to represent and make sense of time requires the mental representations of the ordering of events and temporal relations, abstract time concepts, natural biological rhythms, the self and other through time, and causal relationships. This representational ability undergoes significant refinement in middle childhood concurrent with advances in children’s language and nonverbal skills. This study explored the representational development of temporal cognition, diachronic thinking, and behavioral prediction in relation to a battery of language and nonverbal abilities with the aims of confirming age-related improvements, exploring whether disparate measures are indices of an underlying ability, and examining the role of language and nonverbal abilities. Sixty-two children (32 girls, 30 boys, M=8 years; 2 months, range 6;0-10;8) completed standardized assessments of receptive vocabulary, receptive grammar, reading, nonverbal intelligence, and working memory, in addition to the four representational thought tasks. The temporal cognition tasks consisted of the Months Relative Order task, assessing event ordering ability (e.g., knowledge of the sequence of months), and the Time Labeling task, assessing knowledge of conventional time patterns (e.g., day or month associated with specific events). The diachronic thinking task, Draw Lifecycle of a Tree, assessed awareness of biological change over time and the behavioral prediction task, Character Intentions task (a measure of theory of mind adapted here to assess the ability to predict future behaviors) assessed children’s understanding of causality in time to infer a character’s future actions. The first aim was supported providing confirmation of the age-related improvements in representational thought documented in previous research. Results revealed that accuracy on the Months Relative Order, Time Labeling, Draw Lifecycle of a Tree, and Character Intentions tasks improved with age; however, the Draw Lifecycle of a Tree task was only marginally significant. The second and third aims of the study was to explore whether the four disparate measures of representational were significantly related and if they provided evidence of an underlying ability. All tasks were significantly correlated with one another after controlling for the effects of age. Principal components analysis revealed one underlying factor explaining 57.84% of the variance across tasks. To address the final aim, stepwise regressions explored relationships between this latent variable and developmental changes in nonverbal intelligence, working memory, and language ability. Results revealed that language ability predicted gains in representational thought over and above effects of age, nonverbal intelligence, and working memory. Additionally, mediation analyses showed that the effects of age, nonverbal intelligence, and working memory were mediated by language abilities. These results extend prior work by demonstrating the representational changes occurring in middle childhood across complex cognitive domains while highlighting the role of language as a mechanism promoting representational development

Designing a Summer Transition Program for Incoming and Current College Students on the Autism Spectrum: A Participatory Approach

Students with Autism Spectrum Disorder (ASD) face unique challenges transitioning from high school to college and receive insufficient support to help them navigate this transition. Through a participatory collaboration with incoming and current autistic college students, we developed, implemented, and evaluated two intensive week-long summer programs to help autistic students transition into and succeed in college. This process included: (1) developing an initial summer transition program curriculum guided by recommendations from autistic college students in our ongoing mentorship program, (2) conducting an initial feasibility assessment of the curriculum [Summer Transition Program 1 (STP1)], (3) revising our initial curriculum, guided by feedback from autistic students, to develop a curriculum manual, and (4) pilot-testing the manualized curriculum through a quasi-experimental pre-test/post-test assessment of a second summer program [Summer Transition Program 2 (STP2)]. In STP2, two autistic college students assumed a leadership role and acted as “mentors” and ten incoming and current autistic college students participated in the program as “mentees.” Results from the STP2 pilot-test suggested benefits of participatory transition programming for fostering self-advocacy and social skills among mentees. Autistic and non-autistic mentors (but not mentees) described practicing advanced forms of self-advocacy, specifically leadership, through their mentorship roles. Autistic and non-autistic mentors also described shared (e.g., empathy) and unique (an intuitive understanding of autism vs. an intuitive understanding of social interaction) skills that they contributed to the program. This research provides preliminary support for the feasibility and utility of a participatory approach in which autistic college students are integral to the development and implementation of programming to help less experienced autistic students develop the self-advocacy skills they will need to succeed in college

Variability of extragalactic X-ray jets on kiloparsec scales

Unexpectedly strong X-ray emission from extragalactic radio jets on kiloparsec scales has been one of the major discoveries of Chandra, the only X-ray observatory capable of sub-arcsecond-scale imaging. The origin of this X-ray emission, which appears as a second spectral component from that of the radio emission, has been debated for over two decades. The most commonly assumed mechanism is inverse Compton upscattering of the Cosmic Microwave Background (IC-CMB) by very low-energy electrons in a still highly relativistic jet. Under this mechanism, no variability in the X-ray emission is expected. Here we report the detection of X-ray variability in the large-scale jet population, using a novel statistical analysis of 53 jets with multiple Chandra observations. Taken as a population, we find that the distribution of p-values from a Poisson model is strongly inconsistent with steady emission, with a global p-value of 1.96e-4 under a Kolmogorov-Smirnov test against the expected Uniform (0,1) distribution. These results strongly imply that the dominant mechanism of X-ray production in kpc-scale jets is synchrotron emission by a second population of electrons reaching multi-TeV energies. X-ray variability on the time-scale of months to a few years implies extremely small emitting volumes much smaller than the cross-section of the jet.Comment: Published in Nature Astronomy 29 May 2023; Supplemental Information and Excel File include

Molecular alterations as target for therapy in metastatic osteosarcoma: a review of literature

Treating metastatic osteosarcoma (OS) remains a challenge in oncology. Current treatment strategies target the primary tumour rather than metastases and have a limited efficacy in the treatment of metastatic disease. Metastatic cells have specific features that render them less sensitive to therapy and targeting these features might enhance the efficacy of current treatment. A detailed study of the biological characteristics and behaviour of metastatic OS cells may provide a rational basis for innovative treatment strategies. The aim of this review is to give an overview of the biological changes in metastatic OS cells and the preclinical and clinical efforts targeting the different steps in OS metastases and how these contribute to designing a metastasis directed treatment for OS

The Athena X-ray Integral Field Unit: a consolidated design for the system requirement review of the preliminary definition phase

The Athena X-ray Integral Unit (X-IFU) is the high resolution X-ray spectrometer, studied since 2015 for flying in the mid-30s on the Athena space X-ray Observatory, a versatile observatory designed to address the Hot and Energetic Universe science theme, selected in November 2013 by the Survey Science Committee. Based on a large format array of Transition Edge Sensors (TES), it aims to provide spatially resolved X-ray spectroscopy, with a spectral resolution of 2.5 eV (up to 7 keV) over an hexagonal field of view of 5 arc minutes (equivalent diameter). The X-IFU entered its System Requirement Review (SRR) in June 2022, at about the same time when ESA called for an overall X-IFU redesign (including the X-IFU cryostat and the cooling chain), due to an unanticipated cost overrun of Athena. In this paper, after illustrating the breakthrough capabilities of the X-IFU, we describe the instrument as presented at its SRR, browsing through all the subsystems and associated requirements. We then show the instrument budgets, with a particular emphasis on the anticipated budgets of some of its key performance parameters. Finally we briefly discuss on the ongoing key technology demonstration activities, the calibration and the activities foreseen in the X-IFU Instrument Science Center, and touch on communication and outreach activities, the consortium organisation, and finally on the life cycle assessment of X-IFU aiming at minimising the environmental footprint, associated with the development of the instrument. Thanks to the studies conducted so far on X-IFU, it is expected that along the design-to-cost exercise requested by ESA, the X-IFU will maintain flagship capabilities in spatially resolved high resolution X-ray spectroscopy, enabling most of the original X-IFU related scientific objectives of the Athena mission to be retained. (abridged).Comment: 48 pages, 29 figures, Accepted for publication in Experimental Astronomy with minor editin

The Athena X-ray Integral Field Unit: a consolidated design for the system requirement review of the preliminary definition phase

The Athena X-ray Integral Unit (X-IFU) is the high resolution X-ray spectrometer studied since 2015 for flying in the mid-30s on the Athena space X-ray Observatory. Athena is a versatile observatory designed to address the Hot and Energetic Universe science theme, as selected in November 2013 by the Survey Science Committee. Based on a large format array of Transition Edge Sensors (TES), X-IFU aims to provide spatially resolved X-ray spectroscopy, with a spectral resolution of 2.5 eV (up to 7 keV) over a hexagonal field of view of 5 arc minutes (equivalent diameter). The X-IFU entered its System Requirement Review (SRR) in June 2022, at about the same time when ESA called for an overall X-IFU redesign (including the X-IFU cryostat and the cooling chain), due to an unanticipated cost overrun of Athena. In this paper, after illustrating the breakthrough capabilities of the X-IFU, we describe the instrument as presented at its SRR (i.e. in the course of its preliminary definition phase, so-called B1), browsing through all the subsystems and associated requirements. We then show the instrument budgets, with a particular emphasis on the anticipated budgets of some of its key performance parameters, such as the instrument efficiency, spectral resolution, energy scale knowledge, count rate capability, non X-ray background and target of opportunity efficiency. Finally, we briefly discuss the ongoing key technology demonstration activities, the calibration and the activities foreseen in the X-IFU Instrument Science Center, touch on communication and outreach activities, the consortium organisation and the life cycle assessment of X-IFU aiming at minimising the environmental footprint, associated with the development of the instrument. Thanks to the studies conducted so far on X-IFU, it is expected that along the design-to-cost exercise requested by ESA, the X-IFU will maintain flagship capabilities in spatially resolved high resolution X-ray spectroscopy, enabling most of the original X-IFU related scientific objectives of the Athena mission to be retained. The X-IFU will be provided by an international consortium led by France, The Netherlands and Italy, with ESA member state contributions from Belgium, Czech Republic, Finland, Germany, Poland, Spain, Switzerland, with additional contributions from the United States and Japan.The French contribution to X-IFU is funded by CNES, CNRS and CEA. This work has been also supported by ASI (Italian Space Agency) through the Contract 2019-27-HH.0, and by the ESA (European Space Agency) Core Technology Program (CTP) Contract No. 4000114932/15/NL/BW and the AREMBES - ESA CTP No.4000116655/16/NL/BW. This publication is part of grant RTI2018-096686-B-C21 funded by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe”. This publication is part of grant RTI2018-096686-B-C21 and PID2020-115325GB-C31 funded by MCIN/AEI/10.13039/501100011033