Physics

News & Events

Friday, June 22, 2018

Sewage, Sewage, Everywhere: Land, Air, and Water Exchange of Sewage Bacteria in the Saw Kill Watershed

M. Elias Dueker, Assistant Professor of Environmental Science

The extra-enteric ecology of sewage-indicating bacteria presents complexities for their use in management of water resources. Once released into the environment, these indicators may persist in sediments, and participate in multidirectional microbial exchange among water, sediment, and air. This complicates sewage pollution detection in public waterways, particularly in shallow freshwater tributaries prone to sediment resuspension. To address these challenges, we compared bacterial communities in sediment, water, and air in a small tributary of the Hudson River, above and below a sewage outflow. Using both culture-based and culture-independent methods, we found that sewage-associated bacteria, including sewage indicators, were present in sediment, water, and air on this waterway. Microbial communities from these ecological compartments were distinct, with sediment samples harboring greater microbial diversity than overlying water. Microbial communities responded to precipitation events, with water and sediment samples increasing in similarity with increases in waterway turbidity. While sediment samples clearly harbored sewage-indicating bacteria, they maintained a lower diversity of sewage-associated bacteria when compared to overlying water, suggesting that sediments may selectively promote environmental persistence of sewage-indicating bacteria.
Time: 3:30 pm – 4:00 pm
Location: Reem-Kayden Center Laszlo Z. Bito '60 Auditorium
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Friday, June 29, 2018

Beyond the Diffraction Limit: Imaging and Writing 3D Polymer Nanostructures with Visible Light

Chaitanya K. Ullal, Rensselaer Polytechnic Institute

Recent developments in far-field microscopy have enabled imaging at nanoscale resolutions using visible light. The circumvention of the diffraction limit opens the benefits of optical microscopy to polymer systems at the relevant nanometer length scales. These benefits include the ability to non-destructively provide local, dynamic and three-dimensional structural information. Specific examples related to colloidal crystals and block copolymers that would be challenging to image with contemporary techniques are used to highlight the potential of subdiffraction far-field fluorescence microscopy for the polymer and nanosciences. Ongoing work on imaging of nanoscale variations in cross-link density of colloidal gels and the application of super-resolution optics to lithography will also be presented.

Chaitanya Ullal is an assistant professor in the Department of Materials Science and Engineering at the Rensselaer Polytechnic Institute. He got his PhD in materials science and engineering at MIT and did a postdoc in the lab of Stefan Hell, at the MPI-BPC in Germany. He is a recipient of the NSF CAREER Award and the ACS PRF New Investigator Award. His research interests are related to unconventional nanofabrication, optics and polymers. A current emphasis of the group is the use of optical microscopy with nanoscale resolution to image and pattern nanostructured polymers.
Time: 3:00 pm – 4:00 pm
Location: Reem-Kayden Center Laszlo Z. Bito '60 Auditorium
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    • 2018

      Exoplanets: Worlds Beyond Our Solar System

      June 15
      Reem-Kayden Center Laszlo Z. Bito '60 Auditorium

      The idea that worlds exist beyond our solar system, exoplanets, dates back to the Greek times, but it was not until 1992 that the first exoplanet discovery was accepted by the scientific community. Detections of exoplanets continued at a crawl until the Kepler mission began in 2009. To date, over 3,700 exoplanets have been confirmed using a variety of techniques. The types of exoplanets detected range from incredibility hot, Jupiter-size exoplanets to Earth-like exoplanets that may be habitable for life.
                                                                                                               
      First, we’ll discuss the motivation behind exoplanet science and explore the subject from a historical perspective. We will investigate how some of the detection methods work and discuss their relative successes. Finally, we will conclude by exploring the reflected light of exoplanets in more detail and will discuss two methods of modeling that light.
       

      Astronomy Night: Jupiter over Montgomery Place

      May 17

      Buses leave from Kline South stop at 8:30 pm.

      Join us at the Montgomery Place visitor center for a short talk by Prof. Antonios Kontos on the science of Jupiter—from the days of Galileo to the latest NASA missions—followed by telescope viewing of Jupiter and its moons, a guided tour of the night sky, and a round of ask-a-physicist-anything.

       

      Senior Project Poster Session

      May 17
      Reem-Kayden Center

      Magnetic Nanostructures for Data Storage and Biomedical Applications

      May 11
      Hegeman 107

      Nanostructured materials are materials with one or more dimensions at the nanoscale (10-7-10-9 meters). Examples of nanostructured materials include 2-dimensional ultrathin films, 1-dimensional nanowires, 0-dimensional nanodots, and more complex structures that could have a combination of these characteristics. Nanostructured materials often exhibit new and enhanced properties over their bulk counterparts, so they not only offer ideal material systems for exploring fundamental physics, such as magnetic topological phases, but also hold promise for applications in data storage and biomedical engineering. In this talk, I will report our experimental work on 2D multilayers that host magnetic skyrmions, topologically protected spin textures that have promising applications in Spintronic data storage devices, as well as our work on magnetic disks that form the magnetic vortex state, useful for biomedical applications.

      Richard Feynman’s Legacy and the Mentorship of John Wheeler

      May 4
      Hegeman 107

      Richard Feynman, the Nobel Laureate whose centenary we are celebrating on May 11, was one of the most important American theoretical physicists of all time. His diagrams are used every day in characterizing particle interactions. In my talk, I'll explore how he was influenced by his PhD mentor at Princeton, another well-known physicist, John Wheeler. I'll discuss how the lifelong interplay between the two physicists helped shape Feynman’s key contributions to physics and physics pedagogy, despite clear differences in style and personality between the two.

      Gas Stripping in Nearby Galaxy Groups and Clusters

      April 20
      Hegeman 107

      A long-standing problem in extragalactic astronomy is to understand the correlation between a galaxy's environment and its ability to form new stars. The fraction of red galaxies is much higher in dense environments, whereas blue, star-forming galaxies are more prevalent in rural galactic environments. One could therefore infer that environment plays a role in removing gas from galaxies and may help drive a galaxy's transition from blue and star-forming to red and quiescent. However, many other galaxy properties correlate with environment, such as mass and morphology. I will present results from the Local Cluster Survey, a survey whose goal is to look for evidence of environmentally driven quenching among star-forming galaxies in nearby galaxy groups and clusters. We have studied 200 galaxies over a range of stellar mass, morphology, and environment in an effort to separate the influence of these factors. We find that galaxies in dense environments have more centrally concentrated star formation, and the presence of a bulge seems to enhance the effectiveness of environmental processing. Our results suggest that galaxies in dense environments experience outside-in quenching over a timescale of several gigayears. I will also discuss new work that probes galaxies in the filamentary structure around the Virgo cluster, and the possibility for completing observations of these filament galaxies using Siena College's new telescope.

      Einstein: The Old Sage and the Young Turk

      April 6
      Hegeman 107

      There is a striking difference between the methodology of the young Einstein and that of the old. Starting in the late 1910s, Einstein went from putting empirical data and general physical principles first to putting mathematical elegance first. This switch was the result both of his scientific experience finishing the general theory of relativity and his crushing personal and political experiences during the war years in Berlin. In crisis situations like this, Einstein, invoking Schopenhauer, used science to escape from it all. Building mathematical castles in the sky was better for this purpose than trying to extract information about nature from empirical data. In his later years, Einstein worked mainly in this mathematical speculation mode. The older man accordingly left us with a misleading picture of how his younger self achieved most of the successes for which he is still celebrated today. This has had a harmful influence on theoretical physics. If the young Turk’s successes are any guide as to how successful theoretical physics is done, paying close attention to general features of the empirical data is much more important, and mathematical elegance much less important, than the old sage wanted us to believe.

       

      Distinguished Scientist Scholar Award

      February 26 - April 2

      Distinguished Scientist Scholar Award

      February 26 - April 2

      Distinguished Scientist Scholar Award

      February 26 - April 2

      Distinguished Scientist Scholar Award

      February 26 - April 2

      Distinguished Scientist Scholar Award

      February 26 - April 2

      Distinguished Scientist Scholar Award

      February 26 - April 2

      Distinguished Scientist Scholar Award

      February 26 - April 2

      Distinguished Scientist Scholar Award

      February 26 - April 2

      Distinguished Scientist Scholar Award

      February 26 - April 2

      Distinguished Scientist Scholar Award

      February 26 - April 2

      Distinguished Scientist Scholar Award

      February 26 - April 2

      Distinguished Scientist Scholar Award

      February 26 - April 2

      Distinguished Scientist Scholar Award

      February 26 - April 2

      Distinguished Scientist Scholar Award

      February 26 - April 2

      Distinguished Scientist Scholar Award

      February 26 - April 2

      Distinguished Scientist Scholar Award

      February 26 - April 2

      Distinguished Scientist Scholar Award

      February 26 - April 2

      Distinguished Scientist Scholar Award

      February 26 - April 2

      Distinguished Scientist Scholar Award

      February 26 - April 2

      Distinguished Scientist Scholar Award

      February 26 - April 2

      Distinguished Scientist Scholar Award

      February 26 - April 2

      Distinguished Scientist Scholar Award

      February 26 - April 2

      Distinguished Scientist Scholar Award

      February 26 - April 2

      Distinguished Scientist Scholar Award

      February 26 - April 2

      Distinguished Scientist Scholar Award

      February 26 - April 2

      Distinguished Scientist Scholar Award

      February 26 - April 2

      Distinguished Scientist Scholar Award

      February 26 - April 2

      Distinguished Scientist Scholar Award

      February 26 - April 2

      Distinguished Scientist Scholar Award

      February 26 - April 2

      Distinguished Scientist Scholar Award

      February 26 - April 2

      Distinguished Scientist Scholar Award

      February 26 - April 2

      Distinguished Scientist Scholar Award

      February 26 - April 2

      Distinguished Scientist Scholar Award

      February 26 - April 2

      Distinguished Scientist Scholar Award

      February 26 - April 2

      Distinguished Scientist Scholar Award

      February 26 - April 2

      The Discovery of Global Warming

      February 23
      Hegeman 107


      The history of how we learned about climate change offers a deep look into the way scientists work and how that has changed. When 19th-century scientists discovered the Ice Ages they came up with various explanations, including a decrease of carbon dioxide in the atmosphere. Could humanity’s fossil fuel emissions bring a reverse effect, global warming? The idea found only a few supporters, curious scientists who stepped aside from their usual research to develop “greenhouse gas” calculations and measurements. By 1960 they proved that the idea merited serious research. An onslaught of droughts in the early 1970s brought public attention to climate and intensified research, typically by small teams, but scientists admitted they could not even predict whether the world would get warmer or colder. This was resolved at the end of the 1970s by computer models that found global warming would become obvious around 2000. The implication that the fossil fuel industries must be radically reduced brought political pushback and scientific controversy. Crucial confirmation of the models came from a totally independent direction: research on climates of the distant past (studies that were themselves confirmed through independent lines of attack). Large-scale teamwork was now necessary to advance, and almost no climate scientist worked alone. When the world’s governments devised a novel mechanism to get scientific advice, hundreds and then thousands of experts in diverse fields managed to cooperate. By 2001 they reached a nearly unanimous consensus: dangerous climate change is all but certain within our lifetime. The focus of research turned to the impacts.