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  1. Astronomical source deblending is the process of separating the contribution of individual stars or galaxies (sources) to an image comprised of multiple, possibly overlapping sources. Astronomical sources display a wide range of sizes and brightnesses and may show substantial overlap in images. Astronomical imaging data can further challenge off-the-shelf computer vision algorithms owing to its high dynamic range, low signal-to-noise ratio, and unconventional image format. These challenges make source deblending an open area of astronomical research, and in this work, we introduce a new approach called Partial-Attribution Instance Segmentation that enables source detection and deblending in a manner tractable formore »deep learning models. We provide a novel neural network implementation as a demonstration of the method.« less
    Free, publicly-accessible full text available December 13, 2022
  2. ABSTRACT We discuss the spectral energy distributions and physical properties of six galaxies whose photometric redshifts suggest they lie beyond a redshift z ≃ 9. Each was selected on account of a prominent excess seen in the Spitzer/IRAC 4.5 $\mu$m band which, for a redshift above z = 9.0, likely indicates the presence of a rest-frame Balmer break and a stellar component that formed earlier than a redshift z ≃ 10. In addition to constraining the earlier star formation activity on the basis of fits using stellar population models with BAGPIPES, we have undertaken the necessary, but challenging, follow-up spectroscopy for each candidatemore »using various combinations of Keck/MOSFIRE, VLT/X-shooter, Gemini/FLAMINGOS2, and ALMA. Based on either Lyman-α or [O iii] 88 $\mu$m emission, we determine a convincing redshift of z = 8.78 for GN-z-10-3 and a likely redshift of z = 9.28 for the lensed galaxy MACS0416-JD. For GN-z9-1, we conclude the case remains promising for a source beyond z ≃ 9. Together with earlier spectroscopic data for MACS1149-JD1, our analysis of this enlarged sample provides further support for a cosmic star formation history extending beyond redshifts z ≃ 10. We use our best-fitting stellar population models to reconstruct the past rest-frame UV luminosities of our sources and discuss the implications for tracing earlier progenitors of such systems with the James Webb Space Telescope.« less
  3. Fluorescent portable monitoring systems provide real-time and on-site analysis of a sample solution, avoiding transportation delays and solution degradation. However, some applications, such as environmental monitoring of bodies of water with algae pollution, rely on the temperature control that off-site systems provide for adequate solution results. The goal of this research is the development of a temperature stabilization module for a portable fluorescent sensing platform, which is necessary to prevent inaccurate results. Using a Peltier device-based system, the module heats/cools a solution through digital-to-analog control of the current, using three surface-mounted temperature modules attached to a copper cuvette holder, whichmore »is directly attached to the Peltier device. This system utilizes an in-house algorithm for control, which effectively minimizes temperature overshooting when a change is enacted. Finally, with the use of a sample fluorescent dye, Rhodamine B, the system's controllability is highlighted through the monitoring of Rhodamine B's fluorescence emission decrease as the solution temperature increases.« less
  4. Fluorescence dyes are widely used in biomolecule detection/quantification, flow tracing reference for gases and liquids, pathogen detection, and other life science applications. However, fluorescence emission efficiency of the dyes is easily affected by several parameters, such as polarity, pH, and temperature. Therefore, it is essential to monitor and control these parameters for reliable and accurate measurements. We propose a 3D-printed copper cuvette holder (i.materialise, Belgium) joined with a Peltier-based temperature controller platform for stable reading of fluorescence emission from the dye. For demonstration of temperature effects on fluorescence efficiency, rhodamine B, which is one of the widely used fluorescence standardsmore »and probes in bioscience, was used. For excitation, 530 nm wavelength lighting was utilized for stimulating the rhodamine B. A Peltier device was controlled with different levels of direct current (DC) to demonstrate the temperature controlling capability of the device and fluorescence efficiency of the rhodamine B was tested with a varying temperature level: 20 ºC to 80 ºC. For our device, the temperature will be monitored by temperature ICs that are attached at three different points of the copper body for uniform temperature heating of the solution in a cuvette. We have monitored the temperature distribution of the copper holder with an external temperature monitor, the DT304, and determined that the temperature is maintained to with a 5 ºC. We plan to monitor the solution temperature directly with the use of an infrared temperature sensor positioned down at the opening of the cuvette. The ambient temperature and the temperature of the opposite junction of the Peltier device will be monitored through the use of two thermocouples. An analysis of several different temperature components of the device allow for a better interpretation of what is happening in the system. Moreover, the implementation of a water-cooling apparatus will allow for a way to quickly decrease the temperature of the cuvette when desirable. These features allow for the sample to be monitored efficiently, allowing for proper stabilization techniques and the ability to fluctuate the temperature when required of an application. In summary, we have developed an 3D-printed copper cuvette holder with a Peltier-based temperature controller platform for stable reading of fluorescence emission from the dye or fluorophore solution. Our compact temperature controller system provides viable option for any fluorometers to easily apply it for temperature stabilization during the fluorescence dye testing.« less
  5. Global social media use during natural disasters has been well documented (Murthy et al., 2017). In the U.S., public social media platforms are often a primary venue for those affected by disasters . Some disaster victims believe first responders will see their public posts and that the 9-1-1 telephone system becomes overloaded during crises. Moreover, some feel that the accuracy and utility of information on social media is likely higher than traditional media sources . However, sifting through content during a disaster is often difficult due to the high volume of ‘non-relevant’ content. In addition, text is studied more thanmore »images posted on Twitter, leaving a potential gap in understanding disaster experiences. Images posted on social media during disasters have a high level of complexity (Murthy et al., 2016). Our study responds to O’Neal et al.’s (2017) call-to-action that social media images posted during disasters should be studied using machine learning.« less
  6. When wide-scale flooding occurs in a community not accustomed to floods, health concerns emerge. While official organizations tasked with communicating emerging health information exist, the proliferation of social media makes it possible for average citizens to participate in this conversation. This study used a combination of semi-structured interviews and photo elicitation techniques to explore how citizens used private social media sites to share health information. We found two main categories of health concerns: existing medical conditions and water-created. We further identified six themes that describe the common approaches average citizens used to share health information: Narrating a personal experience, presentingmore »it as a Public Service Announcement, downplaying the contribution, bringing a credible source into the conversation, including external links and sources, and using humor. Together, these findings suggest that citizens need health information during a flood disaster, and when they do not have it available from official sources, they use their private social media to tap into a shared community identity and carefully help one another.« less
  7. Widespread disasters can overload official agencies’ capacity to provide assistance, and often citizen-led groups emerge to assist with disaster response. As social media platforms have expanded, emergent rescue groups have many ways to harness network and mobile tools to coordinate actions and help fellow citizens. This study used semi-structured interviews and photo elicitation techniques to better understand how wide-scale rescues occurred during the 2017 Hurricane Harvey flooding in the Greater Houston, Texas USA area. We found that citizens used diverse apps and social media-related platforms during these rescues and that they played one of three roles: rescuer, dispatcher, or informationmore »compiler. The key social media coordination challenges these rescuers faced were incomplete feedback loops, unclear prioritization, and communication overload. This work-in-progress paper contributes to the field of crisis and disaster response research by sharing the nuances in how citizens use social media to respond to calls for help from flooding victims.« less