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The NGC 3109 Satellite System: The First Systematic Resolved Search for Dwarf Galaxies Around an SMC-mass Host
Get PDFWe report the results of the deepest search to date for dwarf galaxies around NGC 3109, a barred spiral galaxy with a mass similar to that of the Small Magellanic Cloud (SMC), using a semiautomated search method. Using the Dark Energy Camera, we survey a region covering a projected distance of ∼70 kpc of NGC 3109 (D = 1.3 Mpc, Rvir ∼ 90 kpc, M ∼ 108M*) as part of the MADCASH and DELVE-DEEP programs. We introduce a newly developed semiresolved search method, used alongside a resolved search, to identify crowded dwarf galaxies around NGC 3109. Using both approaches, we successfully recover the known satellites Antlia and Antlia B. We identified a promising candidate, which was later confirmed to be a background dwarf through deep follow-up observations. Our detection limits are well defined, with the sample ∼80% complete down to MV ∼ −8.0, and include detections of dwarf galaxies as faint as MV ∼ −6.0. This is the first comprehensive study of a satellite system through resolved stars around an SMC mass host. Our results show that NGC 3109 has more bright (MV ∼ −9.0) satellites than the mean predictions from cold dark matter models, but well within the host-to-host scatter. A larger sample of LMC/SMC-mass hosts is needed to test whether or not the observations are consistent with current model expectations
Beyond peak water security: Household-scale experiential metrics can offer new perspectives on contemporary water challenges in the United States
Get PDFThe U.S. has moved beyond peak water security. Infrastructural degradation, institutional inertia, and climate change are reducing the ability of households and communities to benefit from near-universal safe, adequate, affordable, sustainable water services. Yet, current supply-side research tools, that focus largely on system performance, are not equipped to measure the prevalence and lived experiences of household water insecurity, thus limiting the evidence available to policymakers, utilities, and communities to make decisions about water services. We discuss how demand-side metrics, such as household-level water insecurity scales validated for high-income contexts, such as the U.S., can help stakeholders to better identify local variation in user water issues, guide resource allocation, and improve hazard and disaster response. Targeted infrastructure investments informed by these metrics can enhance water security, reduce reliance on emergency social services, and promote public health and economic vitality. To address 21st-century water challenges effectively, we must integrate experiential measures into local, regional, and national water assessments
A simple model of spiral galaxies from geometric optics
Get PDFWe propose a simple model of spiral galaxies based on the interference of gravitational waves. The interference is deduced from geometric optics analysis of the refractive index profiles that mimic the behavior of gravitational potentials −1/r and r2. We analyze the refractive index profiles, n(r)2 = a + b/r and n(r)2 = a + br2, because they are realistically shaped and yield closed form solutions. The two profiles yield similar physical results, showing that the physical interpretation is not dependent on the exact details of the profile. The first profile yields trajectories that can be elliptical, parabolic, or hyperbolic depending on the value of the constant a. The second profile yields square-root-elliptical trajectories. The elliptically shaped trajectories define spiral wavefronts of discrete circulating propagation modes. They are discrete when the gravitational wavelengths are comparable with the size of the galaxies. Stars tend to gather in the bright fringes of the stationary interferograms, largely independent of the motion of the individual stars, resulting in the spiral shapes of the galaxies. Using this modal approach, we obtain outlines of spiral galaxies with arbitrary number of arms and their spiral lengths. While this model does not capture all the complex physics of galaxies, it does provide a simple interpretation of the shapes so well-known from the astronomical observations
Effect of Tai Chi Practice on the Adaptation to Sensory and Motor Perturbations While Standing in Older Adults
Get PDFTai Chi provides an age-appropriate exercise to decrease fall risks in older adults. However, the exact mechanism underlying the benefits of Tai Chi practice remains an open question. Thus, this study examined how aging and Tai Chi practice impact adaptation to sensory and motor perturbations while standing. We hypothesized that older Tai Chi practitioners would exhibit a decreased reliance on visual processes as sensory and motor perturbations increased, relative to naive healthy older adults. Using rambling and trembling decompositions of the center of pressure (COP) and frequency-domain features, we examined changes in low (0–0.3 Hz), medium (0.3–1 Hz), and high (1–3 Hz) frequency components, reflecting contributions from the visual, vestibular/somatosensory, and proprioceptive systems, respectively, in healthy young adults (HYA), healthy older adults (HOA), and Tai Chi practicing older adults (TCOA). Our results revealed statistically significant condition-by-group interactions in high-frequency COP-x and rambling-x and COP-y components, medium-frequency COP-y components, and all low-frequency components in COP and trembling (p \u3c 0.05). Further, a significant trial-by-group interaction in high-frequency rambling-y was observed (p \u3c 0.05). These results indicate age and Tai-chi-related differences in modulation of sensory contributions to balance as perturbations increase, and with repeated practice, which merit further investigation
LSE-Net: Integrated Segmentation and Ensemble Deep Learning for Enhanced Lung Disease Classification
Get PDFAccurate classification of lung diseases is vital for timely diagnosis and effective treatment of respiratory conditions such as COPD, pneumonia, asthma, and lung cancer. Traditional diagnostic approaches often suffer from limited consistency and elevated false-positive rates, highlighting the demand for more dependable automated systems. To address this challenge, we introduce LSE-Net, an end-to-end deep learning framework that combines precise lung segmentation using an optimized U-Net++ with robust classification powered by an ensemble of DenseNet121 and ResNet50. Leveraging structured hyperparameter tuning and patient-level evaluation, LSE-Net achieves 92.7% accuracy, 96.7% recall, and an F1-score of 94.0%, along with improved segmentation performance (DSC = 0.59 ± 0.01, IoU = 0.523 ± 0.07). These results demonstrate LSE-Net’s ability to reduce diagnostic uncertainty, enhance classification precision, and provide a practical, high-performing solution for real-world clinical deployment in lung disease assessment
Quality and Consumer Acceptance of Chia Seed as an Egg Substitute in Brownies
No full textChia seeds have emerged as a promising natural substitute for eggs in various baked products due to their unique gelling properties and ability to bind ingredients. Their gelling abilities closely mimic the moisture-retention functions of eggs in baked goods. The growing interest in plant-based alternatives creates a larger market for more sustainable foods. However, negative sensory attributes are found in baked goods with high chia seed content. The objective of this research was to explore the acceptance of chia gel as an egg replacer in brownies by documenting changes in product quality and chia functionality as an egg substitute. Brownies were made using Ghirardelli brownie mix, with two applied treatments containing chia gel, replacing 50 and 100 percent eggs (w/w). A sensory evaluation was performed with 120 participants to document their levels of acceptance of five attributes with a five-point hedonic scale: appearance, color, texture, consumer overall opinion, and purchase willingness. There were no significant differences between the 50% (w/w) substitution and control (p \u3e 0.05). A 100% (w/w) substitution showed low acceptance for each attribute except aroma (p \u3c 0.05). Flavor and taste were found to be leading determinants of overall opinion and purchase willingness (p \u3c 0.05). These results highlighted the potential for chia seeds to be a viable alternative when replacing up to half of the egg content in brownies, while still maintaining sensory quality and satisfaction. Future research will explore the rheological properties of chia seed gels and their interaction with macro-/micro molecules in different food systems
Acoustic Presence of Humpback Whales (Megaptera novaeangliae) in U.S. West Coast National Marine Sanctuaries
Get PDFHumpback whales are one of many species of marine mammal that utilize sound in multiple aspects of their lives in the oceans. By collecting acoustic data from multiple areas across the habitat of these animals, we can investigate spatiotemporal patterns in their sound production to better understand their life history strategy. This study uses three years of passive acoustic data collected concurrently from three U.S. West Coast National Marine Sanctuaries to look for spatiotemporal patterns in humpback whale song and non-song vocalizations. Additionally, this study investigated correlations between upwelling conditions and the onset of song to explore links between the environment and the behavior of song production. This study documented year-round song presence on U.S. West Coast feeding grounds for the first time, in addition to clear seasonal trends in song presence and non-song presence that line up with patterns observed in humpback whale populations globally. No link was found between upwelling conditions and the timing of song onset, i.e. the day that whale song becomes regular. At each of the three sites, the timing of song onset was incredibly consistent despite large variations in upwelling. This suggests that humpback whale song production may be more influenced by reproductive phenology, like hormonal cues, as opposed to foraging phenology and could serve as an indicator of migration. A better understanding of what cues whales use to migrate will inform conservation efforts designed at reducing ship strike and entanglement risk by finding ways to minimize the overlap of whales, ships, and fishing gear
Working Memory in Major Depressive Disorder: A Meta-Analysis of Structural and Functional Brain Differences
Get PDFMajor depressive disorder (MDD) is one of the most prevalent mental health disorders in the US and is characterized by depressed mood and loss of interest. Many MDD patients also experience difficulties with executive function, including working memory. Neuroimaging studies reveal structural and functional brain differences between MDD patients and healthy controls that may underlie these working memory difficulties, but findings have been mixed. A quantitative synthesis of neuroimaging data through a meta-analytic approach offers a promising avenue to identify commonalities across studies. We conducted separate meta?analyses of structural and functional magnetic resonance imaging (MRI) data, with the latter focused on studies utilizing the N-back task. We predicted reduced volume in individuals with MDD relative to controls in the hippocampus, prefrontal cortex, and anterior cingulate cortex, whereas we had no strong predictions regarding functional differences due to mixed and often contradictory findings in the literature. No significant effects were found for either the structural or functional meta-analyses when using a statistically conservative approach. Follow-up exploratory analyses revealed reduced volume in depressed individuals in the left superior frontal gyrus and right fusiform gyrus, as well as hyperactivity in the left anterior cingulate cortex. Should these findings be replicated in the future, it would suggest that these neural differences may explain reduced working memory abilities in MDD, potentially supporting the development of customized interventions targeting these regions. Keywords: Working Memory, Major Depressive Disorder, Neuroimaging, Meta-Analysi
Exploring the ANT: How Well Do Three Attention Networks Predict Road Hazard Perception
Get PDFHazard perception is the ability of a driver to anticipate emerging dangers. Driving is a complex activity requiring attention to various stimuli to prevent accidents. Prior studies have shown that older, experienced drivers detect more cues and perceive hazards better than younger, inexperienced drivers. Attention is multifaceted, and three visual attention networks were focused on in the study: alerting (readiness), orienting (spatial focus), and executive control (distraction inhibition). A sample of 95 participants completed two tasks: The Attention Network Test was used to assess these three attention networks, and to measure road hazard awareness, participants viewed short dashcam videos (~233 ms), half of which contained a road hazard and half of which did not. The relationship between the three attention networks and hazard detection performance was examined using hierarchical multiple regression, allowing performance variance due to age and driving experience to be accounted for in the statistical analysis. Results indicated that none of the attention networks predicted hazard detection performance after accounting for driving experience. However, the orienting network showed the strongest (yet statistically non-significant) association with hazard detection. Notably, age was negatively correlated with the orienting network, and age was significantly associated with poorer hazard perception. These findings suggest that while attention may contribute to hazard detection, the attention network test and hazard perception task used in this study did not demonstrate this association