Detection of Airborne Biological Particles in Indoor Air Using a Real-Time Advanced Morphological Parameter UV-LIF Spectrometer and Gradient Boosting Ensemble Decision Tree Classifiers

We present results from a study evaluating the utility of supervised machine learning to classify single particle ultraviolet laser-induced fluorescence (UV-LIF) signatures to investigate airborne primary biological aerosol particle (PBAP) concentrations in a busy, multifunctional building using a Multiparameter Bioaerosol Spectrometer. First we introduce and demonstrate a gradient boosting ensemble decision tree algorithm’s ability to accurately classify laboratory generated PBAP samples into broad taxonomic classes with a high level of accuracy. We then develop a framework to appraise the classification accuracy and performance using the Hellinger distance metric to compare product parameter probability density function similarity; this framework showed that key training classes were sufficiently different in terms of particle fluorescence and morphology to facilitate classification. We also demonstrate the utility of including advanced morphological parameters to minimise inter-class conflation and improve classification confidence, where relying on the fluorescent spectra alone would likely result in misattribution. Finally, we apply these methods to ambient data collected within a large multi-functional building where ambient bacterial- and fungal-like classes were identified to display trends corresponding to human activity; fungal-like classes displayed a consistent diurnal trend with a maximum at midday and hourly peaks correlating to movements within the building; bacteria-like aerosol displayed complex, episodic events during opening hours. All PBAP classes fell to low baseline concentrations when the building was unoccupied overnight and at weekendsPeer reviewe

A preview of JWST metallicity studies at cosmic noon: the first detection of auroral [O II] emission at high redshift

Galaxie

The MOSDEF-LRIS survey: connection between galactic-scale outflows and the properties of z ~ 2 star-forming galaxies

Large scale structure and cosmolog

The MOSDEF survey: a new view of a remarkable z = 1.89 merger

Large scale structure and cosmolog

Reconciling the results of the z ~ 2 MOSDEF and KBSS-MOSFIRE Surveys

Large scale structure and cosmolog

Online peer assessment in higher education: a systematic review of literature in educational practices

Neste artigo procedemos a uma revisão sistemática da literatura sobre Online Peer Assessment (OPA) no Ensino Superior, mediadas por Tecnologias Digitais de Informação e Comunicação (TIC). Identificamos suas características, centrais e opcionais e mapeamos exemplos práticos (procedimentos e TIC) de OPA que poderão ser transversais, adaptáveis e aplicáveis em diversas unidades curriculares e regimes educacionais. Os resultados apontam para a utilização da OPA como uma estratégia que potencia a “avaliação para a aprendizagem”. Os referenciais teóricos subjacentes, os métodos de avaliação e os tipos de TIC utilizadas indicam seu direcionamento para um maior envolvimento e responsabilidade do aluno na sua aprendizagem. Evidenciamos na literatura que se busca desenvolver essas competências, dando ao aluno oportunidades com alguma regularidade para autoavaliar-se e avaliar seus pares por meio de feedback construtivo. Há também evidências de que dar ou produzir feedback é mais benéfico para a aprendizagem do que apenas recebê-lo, como também é cognitivamente mais exigente e envolve os alunos de forma mais ativa e os direciona ao pensamento crítico e a processos metacognitivos. A partir dos resultados alcançados, consideramos que a OPA, enquanto ferramenta cognitiva, contribui para a construção do conhecimento e para a reflexão sobre a aprendizagem. Um desafio que se coloca diz respeito ao desenvolvimento criativo com foco na diversificação e na inovação das práticas de avaliação no sentido de potenciar aprendizagens e resultados acadêmicos, em atenção às necessidades de aprendizagem que se manifestam frente às expectativas da educação atual e futura e às exigências da sociedade.In this research a systematic review of literature about Online Peer Assessment (OPA) in higher education, mediated by Information and Communication Technology (ICT), was carried out. Optional and central characteristics and its practices (procedures and ICT) were identified and mapping. These procedures and practices may be transversal, adaptable and applied in several curriculum units and educational regimes. The results point to the use of OPA as a strategy that enhances “assessment for learning”. The theoretical framework, the methods of assessment and the kinds of ICT used indicate directions for greater involvement and responsibility from the part of the student in his/her learning. Theoretical framework identifies the need to develop students’ skills, providing them with opportunities for self-assessment and peer assessment on a regular basis through constructive feedback. There is also evidence that to give or receive feedback is more beneficial for learning than just receiving it. It is also cognitively more demanding and directs the students to critical thinking and metacognitive processes. From the results obtained, OPA is seen as a cognitive tool, contributing to the building of knowledge and to reflection about learning. Issues for further reflection are also identified such as the creative development of assessment methods with a focus on diversity and innovation in order to enhance students’ learning and academic results, taking into account their learning needs in face of the expectations of current and future education and the demands of society.CIEC - Centro de Investigação em Estudos da Criança, IE, UMinho (UI 317 da FCT), PortugalFundos Nacionais através da FCT (Fundação para a Ciência e a Tecnologia) e cofinanciado pelo Fundo Europeu de Desenvolvimento Regional (FEDER) através do COMPETE 2020 – Programa Operacional Competitividade e Internacionalização (POCI) com a referência POCI-01-0145-FEDER-007562info:eu-repo/semantics/publishedVersio

Spectroscopic confirmation of four metal-poor galaxies at z = 10.3-13.2

Galaxie

Paschen-line Constraints on Dust Attenuation and Star Formation at z ∼ 1-3 with JWST/NIRSpec

We use medium-resolution JWST/NIRSpec observations from the Cosmic Evolution Early Release Science Survey to place the first constraints on dust attenuation and star formation based on Paschen lines for a sizable sample of 63 galaxies at redshifts z = 1.0-3.1. Our analysis indicates strong correlations between the Balmer decrement, Hα/Hβ, and line ratios that include Paschen lines (i.e., Paα/Hβ, Paβ/Hβ, and the Paschen decrement, Paα/Paβ), suggesting that the former is sensitive to the overall dust obscuration toward H ii regions in high-redshift galaxies. The line ratios are used to derive nebular reddening, E(B − V)neb, and star formation rates (SFRs). There is marginal evidence that the SFRs deduced from Paschen lines may exceed by ≈25% those derived from Balmer lines alone, suggesting the presence of star formation that is optically thick in Balmer lines, though deeper observations are needed to confirm this result. Using the Paschen-line constraints on the bolometric SFRs, we reevaluate the relationship between dust obscuration and UV spectral slope, and find a reddening of the UV continuum that, on average, follows the SMC extinction curve. This analysis highlights the need for deeper spectroscopy of more representative samples to evaluate nebular dust attenuation and bolometric SFRs in high-redshift galaxies, and their relationship to the reddening of the UV continuum. © 2023. The Author(s). Published by the American Astronomical Society.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

A JWST/NIRCam study of key contributors to reionization: the star-forming and ionizing properties of UV-faint z ∼7-8 galaxies

Spitzer/Infrared Array Camera (IRAC) imaging has revealed that the brightest z ∼7-8 galaxies often exhibit young ages and strong nebular line emission, hinting at high ionizing efficiency among early galaxies. However, IRAC's limited sensitivity has long hindered efforts to study the fainter, more numerous population often thought largely responsible for reionization. Here, we use Cosmic Evolution Early Release Science (CEERS) JWST/NIRCam data to characterize 116 ultraviolet (UV)-faint (median MUV = -19.5) z ∼6.5-8 galaxies. The spectral energy distributions are typically dominated by young (∼10-50 Myr), low-mass (M∗ ∼108 M⊙) stellar populations, and we find no need for extremely high stellar masses (∼1011 M⊙). Considering previous studies of UV-bright (MUV ∼-22) z ∼7-8 galaxies, we find evidence for a strong (5-10 times) increase in specific star formation rate (sSFR) toward lower luminosities (median sSFR = 103 Gyr-1 in CEERS). The larger sSFRs imply a more dominant contribution from OB stars in the relatively numerous UV-faint population, perhaps suggesting that these galaxies are very efficient ionizing agents (median ζion = 1025.7 erg-1 Hz). In spite of the much larger sSFRs, we find little increase in [O iii] + H β equivalent widths towards fainter MUV (median ≈780). If confirmed, this may indicate that a substantial fraction of our CEERS galaxies possess extremely low metallicities (≲3 per cent Z⊙) where [O iii] emission is suppressed. Alternatively, high ionizing photon escape fractions or bursty star formation histories can also weaken the nebular lines in a subset of our sample. While the majority of galaxies in our sample are very blue (median β = -2.0), we identify a significant tail of very dusty galaxies (β ∼-1) at ≈0.5 which may contribute significantly to the z ∼7-8 star formation rate density. © 2023 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society.Immediate accessThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

The Detection of Ionized Carbon Emission at z ∼ 8

We present deep Keck/MOSFIRE H-band spectroscopic observations covering the [C iii],C iii]λλ1907, 1909 doublet for three z ∼ 8 galaxy candidates in the AEGIS field. Along with nondetections in two galaxies, we obtain one of the highest-redshift detections to date of [C iii]λ1907 for the galaxy AEGIS-33376, finding z spec = 7.945 0.001. We measure a [C iii]λ1907 flux of 2.24 0.71 10-18erg s-1cm-2, corresponding to a rest-frame equivalent width of 20.3 6.5 Å for the single line. Given the not very constraining upper limit for C iii]λ1909 based on strong sky-line contamination, we assume a [C iii]λ1907/C iii]λ1909 doublet ratio of 1.5 and infer a total [C iii][C iii]λλ1907, 1909 equivalent width of 33.7 10.8 Å. We repeat the same reductions and analysis on multiple subsets of our raw data divided on the basis of time and observing conditions, verifying that the [C iii]λ1907 emission is present for AEGIS-33376 throughout our observations. We also confirm that the significance of the [C iii]λ1907 detection in different subsets of our data tracks that of brighter emission features detected on the same multi-slit mask. These multiple tests suggest that the observed emission line is real and associated with the z ∼ 8 target. The strong observed [C iii],C iii]λλ1907, 1909 in AEGIS-33376 likely indicates ISM conditions of low metallicity, high ionization parameter, and a hard ionizing spectrum, although AGN contributions are possible. This single detection represents a sizable increase in the current sample [C iii],C iii]λλ1907, 1909 detections at z > 7, while JWST will provide the first statistical samples of such measurements at these redshifts. © 2021. The American Astronomical Society. All rights reserved..Immediate accessThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]