Showing papers by "San Francisco State University published in 2021"

Highlighting photonics: looking into the next decade

Abstract: Let there be light–to change the world we want to be! Over the past several decades, and ever since the birth of the first laser, mankind has witnessed the development of the science of light, as light-based technologies have revolutionarily changed our lives. Needless to say, photonics has now penetrated into many aspects of science and technology, turning into an important and dynamically changing field of increasing interdisciplinary interest. In this inaugural issue of eLight, we highlight a few emerging trends in photonics that we think are likely to have major impact at least in the upcoming decade, spanning from integrated quantum photonics and quantum computing, through topological/non-Hermitian photonics and topological insulator lasers, to AI-empowered nanophotonics and photonic machine learning. This Perspective is by no means an attempt to summarize all the latest advances in photonics, yet we wish our subjective vision could fuel inspiration and foster excitement in scientific research especially for young researchers who love the science of light.

AdS 3 gravity and random CFT

Abstract: We compute the path integral of three-dimensional gravity with negative cosmological constant on spaces which are topologically a torus times an interval. These are Euclidean wormholes, which smoothly interpolate between two asymptotically Euclidean AdS3 regions with torus boundary. From our results we obtain the spectral correlations between BTZ black hole microstates near threshold, as well as extract the spectral form factor at fixed momentum, which has linear growth in time with small fluctuations around it. The low-energy limit of these correlations is precisely that of a double-scaled random matrix ensemble with Virasoro symmetry. Our findings suggest that if pure three-dimensional gravity has a holographic dual, then the dual is an ensemble which generalizes random matrix theory.

Stop AAPI Hate National Report

Abstract: This report offers aggregated national data and some selected personal testimonials about Asian American experiences with anti-Asian violence. The data is presented by types of discrimination and violence experienced, the ethnic breakdown of those being targeted, and the locations where Asian Americans were targeted.

Nonlinear tuning of PT symmetry and non-Hermitian topological states

Abstract: Topology, parity-time (PT) symmetry, and nonlinearity are at the origin of many fundamental phenomena in complex systems across the natural sciences, but their mutual interplay remains unexplored. We established a nonlinear non-Hermitian topological platform for active tuning of PT symmetry and topological states. We found that the loss in a topological defect potential in a non-Hermitian photonic lattice can be tuned solely by nonlinearity, enabling the transition between PT-symmetric and non-PT-symmetric regimes and the maneuvering of topological zero modes. The interaction between two apparently antagonistic effects is revealed: the sensitivity close to exceptional points and the robustness of non-Hermitian topological states. Our scheme using single-channel control of global PT symmetry and topology via local nonlinearity may provide opportunities for unconventional light manipulation and device applications.

Avoid zoom fatigue, be present and learn

Abstract: This paper explores plausible reasons why some students report having more difficulty learning online, predominantly in Zoom synchronous classes, and suggests strategies that students can do to optimize their learning. During anonymous classroom observations, approximately 80% of 350 college students polled indicated it was harder to focus their attention and stay present while taking classes online. They also reported experiencing more isolation, anxiety, and depression compared to face-to-face classes, although much of this may be due to COVID-19 social isolation. Students often appear nonresponsive when attending online synchronous Zoom classes that negatively impacts the nonverbal dynamics of student-instructor interactions. Communication issues includes internet challenges, lack of facial expressions, body appearance, and movement. Students also report that it is more challenging to maintain attention, especially when they are multitasking. Suggested strategies are to optimize learning that includes arranging the camera so that you are visible, using active facial and body responses as if you are communicating to just one person face-to-face, configuring your body and environment (sitting upright and creating unique cues for each specific task), reducing multitasking and notifications, and optimizing arousal and vision regeneration. © 2021 International Society for Neurofeedback and Research. All rights reserved.

Marine mammal conservation: over the horizon

Abstract: Marine mammals can play important ecological roles in aquatic ecosystems, and their presence can be key to community structure and function. Consequently, marine mammals are often considered indicators of ecosystem health and flagship species. Yet, historical population declines caused by exploitation, and additional current threats, such as climate change, fisheries bycatch, pollution and maritime development, continue to impact many marine mammal species, and at least 25% are classified as threatened (Critically Endangered, Endangered or Vulnerable) on the IUCN Red List. Conversely, some species have experienced population increases/recoveries in recent decades, reflecting management interventions, and are heralded as conservation successes. To continue these successes and reverse the downward trajectories of at-risk species, it is necessary to evaluate the threats faced by marine mammals and the conservation mechanisms available to address them. Additionally, there is a need to identify evidence-based priorities of both research and conservation needs across a range of settings and taxa. To that effect we: (1) outline the key threats to marine mammals and their impacts, identify the associated knowledge gaps and recommend actions needed; (2) discuss the merits and downfalls of established and emerging conservation mechanisms; (3) outline the application of research and monitoring techniques; and (4) highlight particular taxa/populations that are in urgent need of focus.

Introduction to Special Issue: Impacts of the COVID-19 Pandemic on LGBTQ+ Health and Well-Being.

Abstract: This special issue on the impacts of COVID-19 on LGBTQ+ health and well-being reports findings from nine articles with varied study designs, including data from multiple countries and all segments of LGBTQ+ communities. Key findings included the observation that pre-COVID mental health disparities predispose LGBTQ+ people to poorer outcomes; that technological communication aids are essential in maintaining some sense of community; and that substance use is perceived by sexual minority women as a means of coping with fears, stress, loneliness, and boredom. Studies in this special issue also document that community support is still a critical need, particularly among those who are sheltering at home with families of origin. Findings underscore the importance of addressing structural inequities, including advocating for rights; providing financial support for LGBTQ+ community organizations and networks; ensuring access to competent and affirming healthcare; and including vulnerable communities in disaster response and planning.

Structural Racism and Immigrant Health in the United States.

Abstract: Immigration has been historically and contemporarily racialized in the United States. Although each immigrant group has unique histories, current patterns, and specific experiences, racialized immi...

Communicating Scientific Uncertainty in an Age of COVID-19: An Investigation into the Use of Preprints by Digital Media Outlets.

Abstract: In this article, we investigate the surge in use of COVID-19-related preprints by media outlets. Journalists are a main source of reliable public health information during crises and, until recently, journalists have been reluctant to cover preprints because of the associated scientific uncertainty. Yet, uploads of COVID-19 preprints and their uptake by online media have outstripped that of preprints about any other topic. Using an innovative approach combining altmetrics methods with content analysis, we identified a diversity of outlets covering COVID-19-related preprints during the early months of the pandemic, including specialist medical news outlets, traditional news media outlets, and aggregators. We found a ubiquity of hyperlinks as citations and a multiplicity of framing devices for highlighting the scientific uncertainty associated with COVID-19 preprints. These devices were rarely used consistently (e.g., mentioning that the study was a preprint, unreviewed, preliminary, and/or in need of verification). About half of the stories we analyzed contained framing devices emphasizing uncertainty. Outlets in our sample were much less likely to identify the research they mentioned as preprint research, compared to identifying it as simply "research." This work has significant implications for public health communication within the changing media landscape. While current best practices in public health risk communication promote identifying and promoting trustworthy sources of information, the uptake of preprint research by online media presents new challenges. At the same time, it provides new opportunities for fostering greater awareness of the scientific uncertainty associated with health research findings.

Comics-based research: The affordances of comics for research across disciplines:

Abstract: Comics have long been a focus of scholarly inquiry. In recent years, this interest has taken a methodological turn, with scholars integrating comics creation into the research process itself. In th...

Evidence for the Model of Gender Affirmation: The Role of Gender Affirmation and Healthcare Empowerment in Viral Suppression Among Transgender Women of Color Living with HIV

Abstract: Transgender women of color are disproportionately impacted by HIV, poor health outcomes, and transgender-related discrimination (TD). We tested the Model of Gender Affirmation (GA) to identify intervention-amenable targets to enhance viral suppression (VS) using data from 858 transgender women of color living with HIV (49% Latina, 42% Black; 36% virally suppressed) in a serial mediation model. Global fit statistics demonstrated good model fit; statistically significant (p ≤ 0.05) direct pathways were between TD and GA, GA and healthcare empowerment (HCE), and HCE and VS. Significant indirect pathways were from TD to VS via GA and HCE (p = 0.036) and GA to VS via HCE (p = 0.028). Gender affirmation and healthcare empowerment significantly and fully mediated the total effect of transgender-related discrimination on viral suppression. These data provide empirical evidence for the Model of Gender Affirmation. Interventions that boost gender affirmation and healthcare empowerment may improve viral suppression among transgender women of color living with HIV.

Gravitational constrained instantons

Abstract: The authors find constrained instantons -- configurations that extremize the action subject to a constraint -- in Einstein gravity with and without a cosmological constant. Such instantons are expected to contribute to non-perturbative processes in quantum gravity. With negative cosmological constant, these configurations describe wormholes connecting two asymptotic regions.

Nonlinear control of photonic higher-order topological bound states in the continuum.

Abstract: Higher-order topological insulators (HOTIs) are recently discovered topological phases, possessing symmetry-protected corner states with fractional charges. An unexpected connection between these states and the seemingly unrelated phenomenon of bound states in the continuum (BICs) was recently unveiled. When nonlinearity is added to the HOTI system, a number of fundamentally important questions arise. For example, how does nonlinearity couple higher-order topological BICs with the rest of the system, including continuum states? In fact, thus far BICs in nonlinear HOTIs have remained unexplored. Here we unveil the interplay of nonlinearity, higher-order topology, and BICs in a photonic platform. We observe topological corner states that are also BICs in a laser-written second-order topological lattice and further demonstrate their nonlinear coupling with edge (but not bulk) modes under the proper action of both self-focusing and defocusing nonlinearities. Theoretically, we calculate the eigenvalue spectrum and analog of the Zak phase in the nonlinear regime, illustrating that a topological BIC can be actively tuned by nonlinearity in such a photonic HOTI. Our studies are applicable to other nonlinear HOTI systems, with promising applications in emerging topology-driven devices.

Comparative regulomics supports pervasive selection on gene dosage following whole genome duplication.

Abstract: Whole genome duplication (WGD) events have played a major role in eukaryotic genome evolution, but the consequence of these extreme events in adaptive genome evolution is still not well understood. To address this knowledge gap, we used a comparative phylogenetic model and transcriptomic data from seven species to infer selection on gene expression in duplicated genes (ohnologs) following the salmonid WGD 80–100 million years ago. We find rare cases of tissue-specific expression evolution but pervasive expression evolution affecting many tissues, reflecting strong selection on maintenance of genome stability following genome doubling. Ohnolog expression levels have evolved mostly asymmetrically, by diverting one ohnolog copy down a path towards lower expression and possible pseudogenization. Loss of expression in one ohnolog is significantly associated with transposable element insertions in promoters and likely driven by selection on gene dosage including selection on stoichiometric balance. We also find symmetric expression shifts, and these are associated with genes under strong evolutionary constraints such as ribosome subunit genes. This possibly reflects selection operating to achieve a gene dose reduction while avoiding accumulation of “toxic mutations”. Mechanistically, ohnolog regulatory divergence is dictated by the number of bound transcription factors in promoters, with transposable elements being one likely source of novel binding sites driving tissue-specific gains in expression. Our results imply pervasive adaptive expression evolution following WGD to overcome the immediate challenges posed by genome doubling and to exploit the long-term genetic opportunities for novel phenotype evolution.

The influence of decision-making in tree ring-based climate reconstructions

Abstract: Tree-ring chronologies underpin the majority of annually-resolved reconstructions of Common Era climate. However, they are derived using different datasets and techniques, the ramifications of which have hitherto been little explored. Here, we report the results of a double-blind experiment that yielded 15 Northern Hemisphere summer temperature reconstructions from a common network of regional tree-ring width datasets. Taken together as an ensemble, the Common Era reconstruction mean correlates with instrumental temperatures from 1794–2016 CE at 0.79 (p < 0.001), reveals summer cooling in the years following large volcanic eruptions, and exhibits strong warming since the 1980s. Differing in their mean, variance, amplitude, sensitivity, and persistence, the ensemble members demonstrate the influence of subjectivity in the reconstruction process. We therefore recommend the routine use of ensemble reconstruction approaches to provide a more consensual picture of past climate variability.

Maximum CO2 diffusion inside leaves is limited by the scaling of cell size and genome size

Abstract: Maintaining high rates of photosynthesis in leaves requires efficient movement of CO2 from the atmosphere to the mesophyll cells inside the leaf where CO2 is converted into sugar. CO2 diffusion inside the leaf depends directly on the structure of the mesophyll cells and their surrounding airspace, which have been difficult to characterize because of their inherently three-dimensional organization. Yet faster CO2 diffusion inside the leaf was probably critical in elevating rates of photosynthesis that occurred among angiosperm lineages. Here we characterize the three-dimensional surface area of the leaf mesophyll across vascular plants. We show that genome size determines the sizes and packing densities of cells in all leaf tissues and that smaller cells enable more mesophyll surface area to be packed into the leaf volume, facilitating higher CO2 diffusion. Measurements and modelling revealed that the spongy mesophyll layer better facilitates gaseous phase diffusion while the palisade mesophyll layer better facilitates liquid-phase diffusion. Our results demonstrate that genome downsizing among the angiosperms was critical to restructuring the entire pathway of CO2 diffusion into and through the leaf, maintaining high rates of CO2 supply to the leaf mesophyll despite declining atmospheric CO2 levels during the Cretaceous.

Strong coupling from an improved τ vector isovector spectral function

Abstract: We combine ALEPH and OPAL results for the spectral distributions measured in $\ensuremath{\tau}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{0}{\ensuremath{ u}}_{\ensuremath{\tau}}$, $\ensuremath{\tau}\ensuremath{\rightarrow}2{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{0}{\ensuremath{ u}}_{\ensuremath{\tau}}$ and $\ensuremath{\tau}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ensuremath{-}}3{\ensuremath{\pi}}^{0}{\ensuremath{ u}}_{\ensuremath{\tau}}$ decays with (i) recent BABAR results for the analogous $\ensuremath{\tau}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{K}^{0}{\ensuremath{ u}}_{\ensuremath{\tau}}$ distribution and (ii) estimates of the contributions from other hadronic $\ensuremath{\tau}$-decay modes obtained using CVC and electroproduction data, to obtain a new and more precise nonstrange, inclusive vector, isovector spectral function. The BABAR ${K}^{\ensuremath{-}}{K}^{0}$ and CVC/electroproduction results provide us with alternate, entirely data-based input for the contributions of all exclusive modes for which ALEPH and OPAL employed Monte-Carlo-based estimates. We use the resulting spectral function to determine ${\ensuremath{\alpha}}_{s}({m}_{\ensuremath{\tau}})$, the strong coupling at the $\ensuremath{\tau}$ mass scale, employing finite energy sum rules. Using the fixed-order perturbation theory (FOPT) prescription, we find ${\ensuremath{\alpha}}_{s}({m}_{\ensuremath{\tau}})=0.3077\ifmmode\pm\else\textpm\fi{}0.0075$, which corresponds to the five-flavor result ${\ensuremath{\alpha}}_{s}({M}_{Z})=0.1171\ifmmode\pm\else\textpm\fi{}0.0010$ at the $Z$ mass. While we also provide an estimate using contour-improved perturbation theory (CIPT), we point out that the FOPT prescription is to be preferred for comparison with other ${\ensuremath{\alpha}}_{s}$ determinations employing the $\overline{\mathrm{MS}}$ scheme, especially given the inconsistency between CIPT and the standard operator product expansion recently pointed out in the literature. Additional experimental input on the dominant $2\ensuremath{\pi}$ and $4\ensuremath{\pi}$ modes would allow for further improvements to the current analysis.

The R-Process Alliance: Chemodynamically Tagged Groups of Halo r-process-enhanced Stars Reveal a Shared Chemical-evolution History

Abstract: We derive dynamical parameters for a large sample of 446 $r$-process-enhanced (RPE) metal-poor stars in the halo and disk systems of the Milky Way, based on data releases from the $R$-Process Alliance, supplemented by additional literature samples. This sample represents more than a ten-fold increase in size relative to that previously considered by Roederer et al., and, by design, covers a larger range of $r$-process-element enrichment levels. We test a number of clustering analysis methods on the derived orbital energies and other dynamical parameters for this sample, ultimately deciding on application of the HDBSCAN algorithm, which obtains 30 individual Chemo-Dynamically Tagged Groups (CDTGs); 21 contain between 3 and 5 stars, and 9 contain between 6 and 12 stars. Even though the clustering was performed solely on the basis of their dynamical properties, the stars in these CDTGs exhibit statistically significant similarities in their metallicity ([Fe/H]), carbonicity ([C/Fe]), and neutron-capture element ratios ([Sr/Fe], [Ba/Fe], and [Eu/Fe]). These results demonstrate that the RPE stars in these CDTGs have likely experienced common chemical-evolution histories, presumably in their parent satellite galaxies or globular clusters, prior to being disrupted into the Milky Way's halo. We also confirm the previous claim that the orbits of the RPE stars preferentially exhibit pericentric distances that are substantially lower than the present distances of surviving ultra-faint dwarf and canonical dwarf spheroidal galaxies, consistent with the disruption hypothesis. The derived dynamical parameters for several of our CDTGs indicate their association with previously known substructures, Dynamically Tagged Groups, and RPE Groups.

The TESS-Keck Survey. II. An Ultra-short-period Rocky Planet and Its Siblings Transiting the Galactic Thick-disk Star TOI-561

Abstract: We report the discovery of TOI-561, a multiplanet system in the galactic thick disk that contains a rocky, ultra-short-period planet. This bright (V = 10.2) star hosts three small transiting planets identified in photometry from the NASA TESS mission: TOI-561 b (TOI-561.02, P = 0.44 days, Rp = 1.45 ± 0.11 R⊕), c (TOI-561.01, P = 10.8 days, Rp = 2.90 ± 0.13 R⊕), and d (TOI-561.03, P = 16.3 days, Rp = 2.32 ± 0.16 R⊕). The star is chemically ([Fe/H] = -0.41 ± 0.05, [α/Fe] = +0.23 ± 0.05) and kinematically consistent with the galactic thick-disk population, making TOI-561 one of the oldest (10 ± 3 Gyr) and most metal-poor planetary systems discovered yet. We dynamically confirm planets b and c with radial velocities from the W. M. Keck Observatory High Resolution Echelle Spectrometer. Planet b has a mass and density of 3.2 ± 0.8 M⊕ and 5.5+2.0−1.6 g cm-3, consistent with a rocky composition. Its lower-than-average density is consistent with an iron-poor composition, although an Earth-like iron-to-silicates ratio is not ruled out. Planet c is 7.0 ± 2.3 M⊕ and 1.6 ± 0.6 g cm-3, consistent with an interior rocky core overlaid with a low-mass volatile envelope. Several attributes of the photometry for planet d (which we did not detect dynamically) complicate the analysis, but we vet the planet with high-contrast imaging, ground-based photometric follow-up, and radial velocities. TOI-561 b is the first rocky world around a galactic thick-disk star confirmed with radial velocities and one of the best rocky planets for thermal emission studies.

Early-life inflammation primes a T helper 2 cell–fibroblast niche in skin

Abstract: Inflammation early in life can prime the local immune milieu of peripheral tissues, which can cause lasting changes in immunological tone that confer disease protection or susceptibility1. The cellular and molecular mechanisms that prompt changes in immune tone in many nonlymphoid tissues remain largely unknown. Here we find that time-limited neonatal inflammation induced by a transient reduction in neonatal regulatory T cells causes a dysregulation of subcutaneous tissue in mouse skin. This is accompanied by the selective accumulation of type 2 helper T (TH2) cells within a distinct microanatomical niche. TH2 cells are maintained into adulthood through interactions with a fibroblast population in skin fascia that we refer to as TH2-interacting fascial fibroblasts (TIFFs), which expand in response to TH2 cytokines to form subcutaneous fibrous bands. Activation of the TH2–TIFF niche due to neonatal inflammation primes the skin for altered reparative responses to wounding. Furthermore, we identify fibroblasts in healthy human skin that express the TIFF transcriptional signature and detect these cells at high levels in eosinophilic fasciitis, an orphan disease characterized by inflammation and fibrosis of the skin fascia. Taken together, these data define a previously unidentified TH2 cell niche in skin and functionally characterize a disease-associated fibroblast population. The results also suggest a mechanism of immunological priming whereby inflammation early in life creates networks between adaptive immune cells and stromal cells to establish an immunological set-point in tissues that is maintained throughout life. Time-limited skin inflammation in neonatal mice promotes a reciprocal interaction between type 2 helper T cells and fascial fibroblasts that regulates wound repair in later life.

The effects of repetition frequency on the illusory truth effect

Abstract: Repeated information is often perceived as more truthful than new information. This finding is known as the illusory truth effect, and it is typically thought to occur because repetition increases processing fluency. Because fluency and truth are frequently correlated in the real world, people learn to use processing fluency as a marker for truthfulness. Although the illusory truth effect is a robust phenomenon, almost all studies examining it have used three or fewer repetitions. To address this limitation, we conducted two experiments using a larger number of repetitions. In Experiment 1, we showed participants trivia statements up to 9 times and in Experiment 2 statements were shown up to 27 times. Later, participants rated the truthfulness of the previously seen statements and of new statements. In both experiments, we found that perceived truthfulness increased as the number of repetitions increased. However, these truth rating increases were logarithmic in shape. The largest increase in perceived truth came from encountering a statement for the second time, and beyond this were incrementally smaller increases in perceived truth for each additional repetition. These findings add to our theoretical understanding of the illusory truth effect and have applications for advertising, politics, and the propagation of “fake news.”

Immigrant Communities and COVID-19: Strengthening the Public Health Response.

Abstract: The COVID-19 pandemic has exposed the many broken fragments of US health care and social service systems, reinforcing extant health and socioeconomic inequities faced by structurally marginalized immigrant communities. Throughout the pandemic, even during the most critical period of rising cases in different epicenters, immigrants continued to work in high-risk-exposure environments while simultaneously having less access to health care and economic relief and facing discrimination. We describe systemic factors that have adversely affected low-income immigrants, including limiting their work opportunities to essential jobs, living in substandard housing conditions that do not allow for social distancing or space to safely isolate from others in the household, and policies that discourage access to public resources that are available to them or that make resources completely inaccessible. We demonstrate that the current public health infrastructure has not improved health care access or linkages to necessary services, treatments, or culturally competent health care providers, and we provide suggestions for how the Public Health 3.0 framework could advance this. We recommend the following strategies to improve the Public Health 3.0 public health infrastructure and mitigate widening disparities: (1) address the social determinants of health, (2) broaden engagement with stakeholders across multiple sectors, and (3) develop appropriate tools and technologies. (Am J Public Health. 2021;111(S3):S224-S231. https://doi.org/10.2105/AJPH.2021.306433).

Elucidating gene expression adaptation of phylogenetically divergent coral holobionts under heat stress.

Abstract: As coral reefs struggle to survive under climate change, it is crucial to know whether they have the capacity to withstand changing conditions, particularly increasing seawater temperatures. Thermal tolerance requires the integrative response of the different components of the coral holobiont (coral host, algal photosymbiont, and associated microbiome). Here, using a controlled thermal stress experiment across three divergent Caribbean coral species, we attempt to dissect holobiont member metatranscriptome responses from coral taxa with different sensitivities to heat stress and use phylogenetic ANOVA to study the evolution of gene expression adaptation. We show that coral response to heat stress is a complex trait derived from multiple interactions among holobiont members. We identify host and photosymbiont genes that exhibit lineage-specific expression level adaptation and uncover potential roles for bacterial associates in supplementing the metabolic needs of the coral-photosymbiont duo during heat stress. Our results stress the importance of integrative and comparative approaches across a wide range of species to better understand coral survival under the predicted rise in sea surface temperatures.

Disproportionality Reduction in Exclusionary School Discipline: A Best-Evidence Synthesis:

Abstract: A full canon of empirical literature shows that students who are African American, Latinx, or American Indian/Alaskan Native, and students who are male, diagnosed with disabilities, or from low soc...