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  • richardmitnick 7:02 am on March 27, 2017 Permalink | Reply
    Tags: , , UC Riverside,   

    From UC Riverside: “Researchers Crack Structure of Key Protein in Zika Virus” 

    UC Riverside bloc

    UC Riverside

    March 27, 2017
    Iqbal Pittalwala

    1
    The image shows the crystal structure of ZIKV NS5 protein. The regions with different colors represent individual domains or motifs of ZIKV NS5. The black circle marks the location of the potential inhibitor-binding site. Image credit: Song lab, UC Riverside.

    Zika virus (ZIKV), which causes Zika virus disease, is spread to people primarily through the bite of an infected Aedes aegypti or Aedes albopictus mosquito. An infected pregnant woman can pass ZIKV to her fetus during pregnancy or around the time of birth. Sex is yet another way for infected persons to transmit ZIKV to others.

    The genomic replication of the virus is made possible by its “NS5” protein. This function of ZIKV NS5 is unique to the virus, making it an ideal target for anti-viral drug development. Currently, there is no vaccine or medicine to fight ZIKV infection.

    In a research paper just published in Nature Communications, University of California, Riverside scientists report that they have determined the crystal structure of the entire ZIKV NS5 protein and demonstrated that NS5 is functional when purified in vitro. Knowing the structure of ZIKV NS5 helps the researchers understand how ZIKV replicates itself.

    Furthermore, the researchers’ structural analysis of ZIKV NS5 reveals a potential binding site in the protein for an inhibitor, thereby providing a strong basis for developing potential inhibitors against ZIKV NS5 to suppress ZIKV infection. The identification of the inhibitor-binding site of NS5 can now enable scientists to design potential potent drugs to fight ZIKV.

    “We started this work realizing that the full structure of ZIKV NS5 was missing,” said Jikui Song, an assistant professor of biochemistry, who co-led the research with Rong Hai, an assistant professor of plant pathology and microbiology. “The main challenge for us occurred during the protein’s purification process when ZIKV NS5 got degraded – chopped up – by bacterial enzymes.”

    Song, Hai and their colleagues overcame this challenge by developing an efficient protocol for protein purification, which in essence minimizes the purification time for NS5.

    “Our work provides a framework for future studies of ZIKV NS5 and opportunities for drug development against ZIKV based on its structural similarity to the NS5 protein of other flaviviruses, such as the dengue virus,” Hai said. “No doubt, ZIKV therapeutics can benefit from the wealth of knowledge that has already been generated in the dengue virus field.”

    Next, the researchers plan to investigate the antiviral potential on ZIKV NS5 of a chemical compound that has been shown to work effectively in inhibiting the NS5 protein in the dengue virus.

    Song and Hai were joined in the research by graduate students Boxiao Wang (first author), Xiao-Feng Tan, Stephanie Thurmond, Zhi-Min Zhang, and Asher Lin.

    The research was supported by grants to Song from the March of Dimes Foundation, the Sidney Kimmel Foundation for Cancer Research and the National Institutes of Health.

    See the full article here .

    Please help promote STEM in your local schools.

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    Stem Education Coalition

    UC Riverside Campus

    The University of California, Riverside is one of 10 universities within the prestigious University of California system, and the only UC located in Inland Southern California.

    Widely recognized as one of the most ethnically diverse research universities in the nation, UCR’s current enrollment is more than 21,000 students, with a goal of 25,000 students by 2020. The campus is in the midst of a tremendous growth spurt with new and remodeled facilities coming on-line on a regular basis.

    We are located approximately 50 miles east of downtown Los Angeles. UCR is also within easy driving distance of dozens of major cultural and recreational sites, as well as desert, mountain and coastal destinations.

     
  • richardmitnick 10:57 am on March 23, 2017 Permalink | Reply
    Tags: , , , , Tracing Aromatic Molecules in the Early Universe, UC Riverside, University of California-based MOSDEF survey   

    From UC Riverside: “Tracing Aromatic Molecules in the Early Universe” 

    UC Riverside bloc

    UC Riverside

    March 22, 2017
    Sean Nealon
    A molecule found in car engine exhaust fumes that is thought to have contributed to the origin of life on Earth has made astronomers heavily underestimate the amount of stars that were forming in the early Universe, a University of California, Riverside-led study has found.

    1
    In this study, astronomers used data from the Keck and Spitzer telescopes to trace the star forming and dusty regions of galaxies at about 10 billion years ago. The picture in the background shows the GOODS field, one of the five regions in the sky that was observed for this study. Credit: Mario De Leo-Winkler with images from the Spitzer Space Telescope, NASA, ESA and the Hubble Heritage team.

    That molecule is called polycyclic aromatic hydrocarbon (PAH). On Earth it is also found in coal and tar. In space, it is a component of dust, which along with gas, fills the space between stars within galaxies.

    The study, which was just published in the Astrophysical Journal, represents the first time that astronomers have been able to measure variations of PAH emissions in distant galaxies with different properties. It has important implications for the studies of distant galaxies because absorption and emission of energy by dust particles can change astronomers’ views of distant galaxies.

    “Despite the ubiquity of PAHs in space, observing them in distant galaxies has been a challenging task,” said Irene Shivaei, a graduate student at UC Riverside, and leader of the study. “A significant part of our knowledge of the properties and amounts of PAHs in other galaxies is limited to the nearby universe.”

    The research was conducted as part of the University of California-based MOSDEF survey, a study that uses the Keck telescope in Hawaii to observe the content of about 1,500 galaxies when the universe was 1.5 to 4.5 billion years old. The researchers observed the emitted visible-light spectra of a large and representative sample of galaxies during the peak-era of star formation activity in the universe.

    In addition, the researchers incorporated infrared imaging data from the NASA Spitzer Space Telescope and the European Space Agency-operated Herschel Space Observatory to trace the polycyclic aromatic hydrocarbon emission in mid-infrared bands and the thermal dust emission in far-infrared wavelengths.

    The researchers concluded that the emission of polycyclic aromatic hydrocarbon molecules is suppressed in low-mass galaxies, which also have a lower fraction of metals, which are atoms heavier than hydrogen and helium. These results indicate that the polycyclic aromatic hydrocarbon molecules are likely to be destroyed in the hostile environment of low-mass and metal-poor galaxies with intense radiation.

    The researchers also found that the polycyclic aromatic hydrocarbon emission is relatively weaker in young galaxies compared to older ones, which may be due to the fact that polycyclic aromatic hydrocarbon molecules are not produced in large quantities in young galaxies.

    They found that the star-formation activity and infrared luminosity in the universe 10 billion years ago is approximately 30 percent higher than previously measured.

    Studying the properties of the polycyclic aromatic hydrocarbon mid-infrared emission bands in distant universe is of fundamental importance to improving our understanding of the evolution of dust and chemical enrichment in galaxies throughout cosmic time. The planned launch of the James Webb Space Telescope in 2018 will push the boundaries of our knowledge on dust and polycyclic aromatic hydrocarbon in the early universe.

    In addition to Shivaei, the authors are: Naveen Reddy, Brian Siana, and Bahram Mobasher, of UC Riverside; Alice Shapley and Ryan L. Sanders, of UCLA; Mariska Kriek, Sedona H. Price, and Tom Zick, of UC Berkeley; and Alison L. Coil and Mojegan Azadi, of UC San Diego.

    Mario De Leo-Winkler, a postdoctoral researcher in the UCR Department of Physics and Astronomy, made significant contributions to this article.

    See the full article here .

    Please help promote STEM in your local schools.

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    Stem Education Coalition

    UC Riverside Campus

    The University of California, Riverside is one of 10 universities within the prestigious University of California system, and the only UC located in Inland Southern California.

    Widely recognized as one of the most ethnically diverse research universities in the nation, UCR’s current enrollment is more than 21,000 students, with a goal of 25,000 students by 2020. The campus is in the midst of a tremendous growth spurt with new and remodeled facilities coming on-line on a regular basis.

    We are located approximately 50 miles east of downtown Los Angeles. UCR is also within easy driving distance of dozens of major cultural and recreational sites, as well as desert, mountain and coastal destinations.

     
  • richardmitnick 9:06 am on March 8, 2017 Permalink | Reply
    Tags: , , , , Cosmic Environments and Their Influence in Star Formation, , UC Riverside   

    From UC Riverside: “Cosmic Environments and Their Influence in Star Formation” 

    UC Riverside bloc

    UC Riverside

    March 6, 2017
    Sean Nealon

    1
    Simulations of the cosmic web. The filaments connecting structures are shown. Such structures are predicted by numerical simulations of matter distribution in the universe at different times through the age of the universe. Credit: Illustris Simulation

    Researchers at UC Riverside and Caltech team up on Astrophysical Journal paper

    The scaffolding that holds the large-scale structure of the universe constitutes galaxies, dark matter and gas (from which stars are forming), organized in complex networks known as the cosmic web. This network comprises dense regions known as galaxy clusters and groups that are woven together through thread-like structures known as filaments. These filaments form the backbone of the cosmic web and host a large fraction of the mass in the universe, as well as sites of star formation activity.

    While there is ample evidence that environments shape and direct the evolution of galaxies, it is not clear how galaxies behave in the larger, global cosmic web and in particular in the more extended environment of filaments.

    In a joint collaboration between the California Institute of Technology and the University of California, Riverside, astronomers have performed an extensive study of the properties of galaxies within filaments formed at different times during the age of the universe.

    In a just-published paper, astronomers used a sample of 40,000 galaxies in the COSMOS field, a large and contiguous patch of sky with deep enough data to look at galaxies very far away, and with accurate distance measurements to individual galaxies. The large area covered by COSMOS allowed sampling volumes of different densities within the cosmic web.

    Using techniques developed to identify the large-scale structures, they cataloged the cosmic web to its components: clusters, filaments, and sparse regions devoid of any object, extending into the universe as it was 8 billion years ago. The galaxies were then divided into those that are central to their local environment (the center of gravity) and those that roam around in their host environments (satellites).

    “What makes this study unique is the observation of thousands of galaxies in different filaments spanning a significant fraction of the age of the Universe” said Behnam Darvish a postdoctoral scholar at Caltech who is the lead author on the paper. “When we consider the distant universe, we look back in time to when the cosmic web and filaments were younger and had not yet fully evolved and therefore, could study the joint evolution of the large scale structures and galaxies associated with them.”

    2
    Observational data in the COSMOS survey show filamentary structures at different redshifts (look-back times). At higher redshifts, galaxies become younger and one could look at the newly formed structures. No image credit.

    The researchers measured the star formation activity in galaxies located in different environments.

    “It was reassuring when we found that the average star-formation activity declined from the sparsely populated regions of the cosmic web to mildly populated filaments and dense clusters,” said Bahram Mobasher, a professor of physics and astronomy at the University of California, Riverside. “However, the surprising finding was that the decline was especially steep for satellite galaxies.”

    He emphasized: “The inevitable conclusion from this was that the majority of satellite galaxies stop forming stars relatively fast during the last 5 billion years as they fall to dense environments of clusters by way of the filaments, while this process is much slower for central galaxies.”

    The fast cessation of star formation experienced by satellite galaxies can be explained by “ram-pressure stripping,” which is loss of star-forming gas within a galaxy as it moves within a denser environment, such as a cluster.

    “Compared to the central galaxies, it is the smaller gravitational pull of the satellite galaxies produced by their smaller mass, that results in a more efficient loss of gas and hence, a slow-down in star formation activity with respect to the more massive central galaxies” said Chris Martin, a professor of astronomy at Caltech.

    This investigation served as a pilot study for future large-volume and relatively deep surveys, which will peer into dimmer and younger galaxies in the Universe, such as LSST, Euclid, and WFIRST.

    In addition to Darvish, Mobasher and Martin, the authors are: Nick Scoville and Shoubaneh Hemmati of Caltech, David Sobral of Lancaster University in the United Kingdom, Andra Stroe of the European Southern Observatory, and Jeyhan Kartaltepe of the Rochester Institute of Technology.

    The research was funded by NASA.

    Mario De Leo Winkler, a postdoctoral researcher in the UCR Department of Physics and Astronomy, made significant contributions to this article.

    See the full article here .

    Please help promote STEM in your local schools.

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    Stem Education Coalition

    UC Riverside Campus

    The University of California, Riverside is one of 10 universities within the prestigious University of California system, and the only UC located in Inland Southern California.

    Widely recognized as one of the most ethnically diverse research universities in the nation, UCR’s current enrollment is more than 21,000 students, with a goal of 25,000 students by 2020. The campus is in the midst of a tremendous growth spurt with new and remodeled facilities coming on-line on a regular basis.

    We are located approximately 50 miles east of downtown Los Angeles. UCR is also within easy driving distance of dozens of major cultural and recreational sites, as well as desert, mountain and coastal destinations.

     
  • richardmitnick 1:36 pm on October 27, 2016 Permalink | Reply
    Tags: , , Cosmic Horseshoe, , , UC Riverside   

    From UC Riverside: “The Cosmic Horseshoe Is Not the Lucky Beacon That Astronomers Had Hoped For” 

    UC Riverside bloc

    UC Riverside

    10.26.16

    A UC Riverside-lead team of astronomers used a new approach by using the gravitationally lensed galaxy to try to measure the escaping fraction of photons.

    1

    INTRODUCTION

    Around 380,000 years after the Big Bang, electrons and protons bound together to form hydrogen atoms for the first time. They make up more than 90% of the atoms in the universe, and can very efficiently absorb high-energy photons and become ionized. However, there were very few energetic sources to ionize these atoms in the early universe. One billion years after the Big Bang, the material between the galaxies was reionized (transparent). The main energy source of the reionization is widely believed to be massive stars formed within early galaxies. These stars had a short lifespan and were usually born in the midst of dense gas clouds, which made it very hard for ionizing photons to escape their host galaxies.

    Previous studies suggested that about 20 percent of these ionizing photons need to escape the dense-gas environment of their host galaxies to significantly contribute to the reionization of the material between galaxies. Unfortunately, a direct detection of these ionizing photons is very challenging and previous efforts have not been very successful. Therefore, the mechanisms leading to their escape are poorly understood.

    This has led many astrophysicists to use indirect methods to estimate the fraction of ionizing photons that escape the galaxies. In one popular method, the gas is assumed to have a “picket fence” distribution, where the space between the stars and the edges of galaxies is assumed to be composed of either regions of very little gas, which are transparent to ionizing light, or regions of dense gas, which are opaque. Researchers can determine the fraction of each of these regions by studying the light (spectra) emerging from the galaxies.

    In this new study, astronomers directly measured the fraction of ionizing photons escaping from the Cosmic Horseshoe. The Horseshoe is a distant galaxy that is gravitationally lensed. Gravitational lensing is the deformation and amplification of a background object by the curving of space and time due to the mass of a foreground galaxy”, said Kaveh Vasei, graduate student of astronomy at UC Riverside and lead author of the new study. “The details of the galaxy in the background are therefore magnified, allowing us to study its light and physical properties more clearly.”

    RESULTS

    Based on the picket fence model, an escape fraction of 40% for ionizing photons from the Horseshoe was expected. Therefore, the Horseshoe represented an ideal opportunity to get a clear, resolved image of leaking ionizing photons for the first time, to help us understand the mechanisms by which they escape their host galaxies.

    The research team obtained a deep-image of the Horseshoe with the Hubble Space Telescope in an ultraviolet filter, enabling them to directly detect escaping ionizing photons. Surprisingly, the image did not detect ionizing photons coming from the Horseshoe. This team constrained the fraction of escaping photons to be less than 8%, five times smaller than what had been inferred by indirect methods widely used by astronomers.

    “The study concludes that the previously determined fraction of escaping ionizing radiation of galaxies, as estimated by the most popular indirect method, is likely overestimated in many galaxies,” added Prof. Brian Siana, co-author of the research paper and a professor at UC Riverside. “The team is now focusing on direct determination the fraction of escaping ionizing photons that do not rely on indirect estimates.”

    This paper has been published in the Astrophysical Journal and is authored by Kaveh Vasei (UC Riverside), Brian Siana (UC Riverside), Alice E. Shapley (UCLA), Anna M. Quider (University of Cambridge, UK), Anahita Alavi (UC Riverside), Marc Rafelski (Goddard Space Flight Center / NASA), Charles C. Steidel (Caltech), Max Pettini (University of Cambridge, UK), Geraint F. Lewis (University of Sydney)

    See the full article here .

    Please help promote STEM in your local schools.

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    Stem Education Coalition

    UC Riverside Campus

    The University of California, Riverside is one of 10 universities within the prestigious University of California system, and the only UC located in Inland Southern California.

    Widely recognized as one of the most ethnically diverse research universities in the nation, UCR’s current enrollment is more than 21,000 students, with a goal of 25,000 students by 2020. The campus is in the midst of a tremendous growth spurt with new and remodeled facilities coming on-line on a regular basis.

    We are located approximately 50 miles east of downtown Los Angeles. UCR is also within easy driving distance of dozens of major cultural and recreational sites, as well as desert, mountain and coastal destinations.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    UC Riverside Campus

    The University of California, Riverside is one of 10 universities within the prestigious University of California system, and the only UC located in Inland Southern California.

    Widely recognized as one of the most ethnically diverse research universities in the nation, UCR’s current enrollment is more than 21,000 students, with a goal of 25,000 students by 2020. The campus is in the midst of a tremendous growth spurt with new and remodeled facilities coming on-line on a regular basis.

    We are located approximately 50 miles east of downtown Los Angeles. UCR is also within easy driving distance of dozens of major cultural and recreational sites, as well as desert, mountain and coastal destinations.

     
  • richardmitnick 1:10 pm on September 13, 2016 Permalink | Reply
    Tags: , , Explaining Why the Universe Can Be Transparent, , UC Riverside   

    From UC Riverside: “Explaining Why the Universe Can Be Transparent” 

    UC Riverside bloc

    UC Riverside

    September 12, 2016
    Sean Nealon

    1
    Reionization as illustrated by data from the Hubble and Chandra space telescopes. Credit: NASA/CXC/M.Weiss.

    Two papers published by an assistant professor at the University of California, Riverside and several collaborators explain why the universe has enough energy to become transparent.

    The study led by Naveen Reddy, an assistant professor in the Department of Physics and Astronomy at UC Riverside, marks the first quantitative study of how the gas content within galaxies scales with the amount of interstellar dust.

    This analysis shows that the gas in galaxies is like a “picket fence,” where some parts of the galaxy have little gas and are directly visible, whereas other parts have lots of gas and are effectively opaque to ionizing radiation. The findings were just published in The Astrophysical Journal.

    The ionization of hydrogen is important because of its effects on how galaxies grow and evolve. A particular area of interest is assessing the contribution of different astrophysical sources, such as stars or black holes, to the budget of ionizing radiation.

    Most studies suggest that faint galaxies are responsible for providing enough radiation to ionize the gas in the early history of the universe. Moreover, there is anecdotal evidence that the amount of ionizing radiation that is able to escape from galaxies depends on the amount of hydrogen within the galaxies themselves.

    The research team led by Reddy developed a model that can be used to predict the amount of escaping ionizing radiation from galaxies based on straightforward measurements on how “red,” or dusty, their spectra appear to be.

    Alternatively, with direct measurements of the ionizing escape fraction, their model may be used to constrain the intrinsic production rate of ionizing photons at around two billion years after the Big Bang.

    These practical applications of the model will be central to the interpretation of escaping radiation during the cosmic “dark ages,” a topic that is bound to flourish with the coming of 30-meter telescopes, which will allow for research unfeasible today, and the James Webb Space Telescope, NASA’s next orbiting observatory and the successor to the Hubble Space Telescope.

    The research ties back to some 400,000 years after the Big Bang, when the universe entered the cosmic “dark ages,” where galaxies and stars had yet to form amongst the dark matter, hydrogen and helium.

    A few hundred million years later, the universe entered the “Epoch of Reionization,” where the gravitational effects of dark matter helped hydrogen and helium coalesce into stars and galaxies. A great amount of ultraviolet radiation (photons) was released, stripping electrons from surrounding neutral environments, a process known as “cosmic reionization.”

    Reionization, which marks the point at which the hydrogen in the Universe became ionized, has become a major area of current research in astrophysics. Ionization made the Universe transparent to these photons, allowing the release of light from sources to travel mostly freely through the cosmos.

    The data for this research was acquired through the low resolution imaging spectrograph on the W.M. Keck Observatory.

    Keck Observatory, Mauna Kea, Hawaii, USA
    Keck Observatory Interior
    Keck Observatory, Mauna Kea, Hawaii, USA

    The collaborators of this research are Charles Steidel (Caltech), Max Pettini (University of Cambridge), Milan Bogosavljevic (Astronomical Observatory, Belgrade) and Alice Shapley (UCLA).

    The papers are Spectroscopic Measurements of the Far-Ultraviolet Dust Attenuation Curve at z~3 and The Connection Between Reddening, Gas Covering Fraction, and the Escape of Ionizing Radiation at High Redshift.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    UC Riverside Campus

    The University of California, Riverside is one of 10 universities within the prestigious University of California system, and the only UC located in Inland Southern California.

    Widely recognized as one of the most ethnically diverse research universities in the nation, UCR’s current enrollment is more than 21,000 students, with a goal of 25,000 students by 2020. The campus is in the midst of a tremendous growth spurt with new and remodeled facilities coming on-line on a regular basis.

    We are located approximately 50 miles east of downtown Los Angeles. UCR is also within easy driving distance of dozens of major cultural and recreational sites, as well as desert, mountain and coastal destinations.

     
  • richardmitnick 5:52 pm on July 18, 2016 Permalink | Reply
    Tags: , , , UC Riverside   

    From UCR: “Better Understanding Post-Earthquake Fault Movement” 

    UC Riverside bloc

    UC Riverside

    July 18, 2016
    Sean Nealon
    Tel: (951) 827-1287
    sean.nealon@ucr.edu

    1
    Schematic summary of research findings showing the sequence of slip behavior.

    Preparation and good timing enabled Gareth Funning and a team of researchers to collect a unique data set following the 2014 South Napa earthquake that showed different parts of the fault, sometimes only a few kilometers apart, moved at different speeds and at different times.

    Aided by GPS measurements made just weeks before the earthquake and data from a new radar satellite, the team found post-earthquake fault movement, known as afterslip, was concentrated in areas of loosely packed sediment. Areas where the fault passed through bedrock tended to slip more during the actual earthquake.

    Sections of Highway 12, which runs through the earthquake zone, were broken during the initial 6.0 magnitude earthquake and were further damaged in the coming days due to afterslip. In some areas the afterslip damage exceeded the initial damage from the earthquake.

    “No one has seen variability in afterslip like we saw,” said Funning, an associate professor of earth sciences at the University of California, Riverside. “This helps us address a big question: Can we use geology as a proxy for fault behavior? Our findings suggest there is a relationship between those two things.”

    The findings could have significant implications for earthquake hazard models, and also for planning earthquake response. If geological information can give a guide to the likely extent of future earthquakes, better forecasts of earthquake damage will be possible. And if areas likely to experience afterslip can be identified in advance, it can be taken into account when building or repairing infrastructure that crosses those faults.

    California, in particular the Hayward and Calaveras Faults, which run along the east side of the San Francisco Bay, seems more susceptible to afterslip than other earthquake-prone regions throughout the world, Funning said.

    The findings on the South Napa earthquake were recently published in paper, Spatial variations in fault friction related to lithology from rupture and afterslip of the 2014 South Napa, California, earthquake, in the journal Geophysical Research Letters.

    Funning’s work in the region just north of San Francisco dates back to 2006, when he was a post-doctoral researcher at UC Berkeley and noticed the area wasn’t that well studied, at least compared to the central Bay Area.

    He continued the research after he was hired at UC Riverside and received funding from the United States Geological Survey to conduct surveys using GPS sensors in earthquake prone areas throughout Marin, Napa, Sonoma, Mendocino and Lake counties.

    He began the most recent survey in July 2014. When the South Napa earthquake struck on Aug. 24, 2014, he and three other researchers were in Upper Lake, CA in Lake County, about 70 miles north of the earthquake’s epicenter, making additional measurements.

    The earthquake occurred at 3:20 a.m. By noon, Funning and the other researchers, Michael Floyd (a former post-doctoral researcher with Funning who is now a research scientist at the Massachusetts Institute of Technology), Jerlyn Swiatlowski (a graduate student working with Funning) and Kathryn Materna (a graduate student at UC Berkeley), had deployed additional GPS sensors in the earthquake zone in locations that they had, fortuitously, measured just seven weeks earlier.

    In total, there were more than 20 GPS sensors set up by Funning’s team and scientists from the United States Geological Survey. They left the equipment out for four weeks following the earthquake.

    They then combined the GPS sensor data with remote sensing data. The South Napa earthquake was the first major earthquake to be imaged by Sentinel-1A, a European radar imaging satellite launched in 2014 that provides higher resolution information than was previously available.

    In addition to Funning, authors of the paper are: Floyd, Richard J. Walters, John R. Elliott, Jerry L. Svarc, Jessica R. Murray, Andy J. Hooper, Yngvar Larsen, Petar Marinkovic, Roland Bürgmann, Ingrid A. Johanson and Tim J. Wright.

    See the full article here .

    Meet The Quake-Catcher Network

    QCN bloc

    Quake-Catcher Network

    The Quake-Catcher Network is a collaborative initiative for developing the world’s largest, low-cost strong-motion seismic network by utilizing sensors in and attached to internet-connected computers. With your help, the Quake-Catcher Network can provide better understanding of earthquakes, give early warning to schools, emergency response systems, and others. The Quake-Catcher Network also provides educational software designed to help teach about earthquakes and earthquake hazards.

    After almost eight years at Stanford, and a year at CalTech, the QCN project is moving to the University of Southern California Dept. of Earth Sciences. QCN will be sponsored by the Incorporated Research Institutions for Seismology (IRIS) and the Southern California Earthquake Center (SCEC).

    The Quake-Catcher Network is a distributed computing network that links volunteer hosted computers into a real-time motion sensing network. QCN is one of many scientific computing projects that runs on the world-renowned distributed computing platform Berkeley Open Infrastructure for Network Computing (BOINC).

    BOINCLarge

    BOINC WallPaper

    The volunteer computers monitor vibrational sensors called MEMS accelerometers, and digitally transmit “triggers” to QCN’s servers whenever strong new motions are observed. QCN’s servers sift through these signals, and determine which ones represent earthquakes, and which ones represent cultural noise (like doors slamming, or trucks driving by).

    There are two categories of sensors used by QCN: 1) internal mobile device sensors, and 2) external USB sensors.

    Mobile Devices: MEMS sensors are often included in laptops, games, cell phones, and other electronic devices for hardware protection, navigation, and game control. When these devices are still and connected to QCN, QCN software monitors the internal accelerometer for strong new shaking. Unfortunately, these devices are rarely secured to the floor, so they may bounce around when a large earthquake occurs. While this is less than ideal for characterizing the regional ground shaking, many such sensors can still provide useful information about earthquake locations and magnitudes.

    USB Sensors: MEMS sensors can be mounted to the floor and connected to a desktop computer via a USB cable. These sensors have several advantages over mobile device sensors. 1) By mounting them to the floor, they measure more reliable shaking than mobile devices. 2) These sensors typically have lower noise and better resolution of 3D motion. 3) Desktops are often left on and do not move. 4) The USB sensor is physically removed from the game, phone, or laptop, so human interaction with the device doesn’t reduce the sensors’ performance. 5) USB sensors can be aligned to North, so we know what direction the horizontal “X” and “Y” axes correspond to.

    If you are a science teacher at a K-12 school, please apply for a free USB sensor and accompanying QCN software. QCN has been able to purchase sensors to donate to schools in need. If you are interested in donating to the program or requesting a sensor, click here.

    BOINC is a leader in the field(s) of Distributed Computing, Grid Computing and Citizen Cyberscience.BOINC is more properly the Berkeley Open Infrastructure for Network Computing, developed at UC Berkeley.

    Earthquake safety is a responsibility shared by billions worldwide. The Quake-Catcher Network (QCN) provides software so that individuals can join together to improve earthquake monitoring, earthquake awareness, and the science of earthquakes. The Quake-Catcher Network (QCN) links existing networked laptops and desktops in hopes to form the worlds largest strong-motion seismic network.

    Below, the QCN Quake Catcher Network map
    QCN Quake Catcher Network map

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    UC Riverside Campus

    The University of California, Riverside is one of 10 universities within the prestigious University of California system, and the only UC located in Inland Southern California.

    Widely recognized as one of the most ethnically diverse research universities in the nation, UCR’s current enrollment is more than 21,000 students, with a goal of 25,000 students by 2020. The campus is in the midst of a tremendous growth spurt with new and remodeled facilities coming on-line on a regular basis.

    We are located approximately 50 miles east of downtown Los Angeles. UCR is also within easy driving distance of dozens of major cultural and recreational sites, as well as desert, mountain and coastal destinations.

     
  • richardmitnick 2:33 pm on July 8, 2016 Permalink | Reply
    Tags: , , Study Explains Why Galaxies Stop Creating Stars, UC Riverside   

    From UC Riverside: “Study Explains Why Galaxies Stop Creating Stars” 

    UC Riverside bloc

    UC Riverside

    July 8, 2016
    Iqbal Pittalwala

    1
    ESO 137-001 is a perfect example of a spiral galaxy zipping through a crammed cluster of galaxies. Gas is being pulled from its disc in a process called ram pressure stripping. The galaxy appears to be losing gas as it plunges through the Norma galaxy cluster. Photo credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA).

    Galaxies come in three main shapes – elliptical, spiral (such as the Milky Way) and irregular. They can be massive or small. To add to this mix, galaxies can also be blue or red. Blue galaxies are still actively forming stars. Red ones mostly are not currently forming stars, and are considered passive.

    The processes that cause galaxies to “quench,” that is, cease star formation, are not well understood, however, and constitute an outstanding problem in the study of the evolution of galaxies. Now, using a large sample of around 70,000 galaxies, a team of researchers led by University of California, Riverside astronomers Behnam Darvish and Bahram Mobasher may have an explanation for why galaxies stop creating stars.

    The research team, which included scientists at the California Institute of Technology and Lancaster University, United Kingdom, combed through available data from the COSMOS UltraVISTA survey that give accurate distance estimates for galaxies over the past 11 billion years, and focused on the effects of external and internal processes that influence star formation activity in galaxies.

    External mechanisms, the research team notes, include drag generated from an infalling galaxy within a cluster of galaxies, which pulls gas away; multiple gravitational encounters with other galaxies and the dense surrounding environment, resulting in material being stripped away from the galaxy; and the halting of the supply of cold gas to the galaxy, thus strangling the galaxy of the material needed to produce new stars over a prolonged period of time.

    The researchers explain that internal mechanisms include the presence of a black hole (in which jets, winds, or intense radiation heat up hydrogen gas in the galaxy or blow it out completely, thus preventing the gas from cooling and contracting to form stars) and “stellar outflow” (for example, high-velocity winds produced by massive young stars and supernovae that push the gas out of the host galaxy).

    “By using the observable properties of the galaxies and sophisticated statistical methods, we show that, on average, external processes are only relevant to quenching galaxies during the last eight billion years,” said Darvish, a former graduate student in the UC Riverside Department of Physics and Astronomy and the first author of the research paper that appears today in The Astrophysical Journal. “On the other hand, internal processes are the dominant mechanism for shutting off star-formation before this time, and closer to the beginning of the universe.”

    The finding gives astronomers an important clue towards understanding which process dominates quenching at various cosmic times. As astronomers detect quenched non-star-forming galaxies at different distances (and therefore times after the Big Bang), they now can more easily pinpoint what quenching mechanism was at work.

    In astronomy, much debate continues on whether it is only internal, external or a combination of both phenomena that makes a galaxy quench star formation. It is still not clear what processes are mostly responsible, and unclear, too, is the fractional role of different physical processes in shutting down the star-formation. It is also not fully understood when these processes come to play an important role in the evolutionary life of galaxies.

    “The situation becomes more complex when we realize that all these mechanisms may depend on properties of galaxies being quenched, they may evolve with time, they act at different time-scales – fast or slow – and they may depend on the properties of the quenching factors as well,” Darvish said.

    Mobasher, a professor of physics and astronomy who supervised Darvish during the course of the research, said, “We found that on average the external processes act in a relatively short time-scale, around one billion years, and can more efficiently quench galaxies that are more massive. Internal effects are more efficient in dense clusters of galaxies. The time-scale is very important. A short time-scale suggests that we need to look for external physical processes that are fast in quenching. Another important result of the work is that internal and external processes do not act independently of each other in shutting-off the star formation.”

    Darvish and Mobasher were joined in the research by David Sobral at Lancaster University, the United Kingdom; and Alessandro Rettura, Nick Scoville, Andreas Faisst and Peter Capak at the California Institute of Technology. Darvish graduated from UCR with a Ph.D. in astronomy in 2015. The bulk of the research was done while he was working toward his doctoral degree. He is now a postdoctoral scholar at Caltech.

    Next, the research team will work on extending this study to the environment of galaxies on much larger scales (in the cosmic web).

    The research was funded by financial support from NASA.

    See the full article here .

    Please help promote STEM in your local schools.

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    UC Riverside Campus

    The University of California, Riverside is one of 10 universities within the prestigious University of California system, and the only UC located in Inland Southern California.

    Widely recognized as one of the most ethnically diverse research universities in the nation, UCR’s current enrollment is more than 21,000 students, with a goal of 25,000 students by 2020. The campus is in the midst of a tremendous growth spurt with new and remodeled facilities coming on-line on a regular basis.

    We are located approximately 50 miles east of downtown Los Angeles. UCR is also within easy driving distance of dozens of major cultural and recreational sites, as well as desert, mountain and coastal destinations.

     
  • richardmitnick 3:51 pm on May 17, 2016 Permalink | Reply
    Tags: , Study Advances Understanding of Colon Cancer and Colitis, UC Riverside   

    From UC Riverside: “Study Advances Understanding of Colon Cancer and Colitis” 

    UC Riverside bloc

    UC Riverside

    May 17, 2016
    Iqbal Pittalwala

    1
    Balance between the two isoforms, P1 and P2, of nuclear receptor HNF4-alpha in the colonic crypt influences susceptibility to colitis and colon cancer. P1 is seen here in green. P2 is seen in red. Image credit: Poonamjot Deol, Sladek lab, UC Riverside.
    __________________________________________

    Inflammatory bowel disease (IBD), of which Crohn’s disease and ulcerative colitis are the main types, is on the increase in the United States, affecting more than 1.6 million people and explaining perhaps the increase in advertisements offering treatments and cures. Another intestinal disease is colon cancer, a leading cause of death, which is linked to diet and one’s genetic predisposition to the disease.

    What is already known in the field of cell biology is that a transcription factor, called hepatocyte nuclear factor 4-alpha (HNF4-alpha), plays a key role in both diseases, transcription factors being proteins that help transcribe DNA into its close cousin, RNA, which is then translated into proteins which do the work of the cell. HNF4-alpha comes in two major isoforms, P1-HNF4-alpha and P2-HNF4-alpha (hereafter P1 and P2, respectively), but just how these isoforms are distributed in the gut and how each isoform plays a role in colitis and colon cancer are not understood.

    Now a team of researchers at the University of California, Riverside has determined the distribution of the P1 and P2 isoforms in the colon. They report* in the journal eLife that maintaining a balance of P1 and P2 is crucial for reducing risk of contracting colon cancer and colitis.

    “P1 and P2 have been conserved between mice and humans for 70 million years,” said Frances M. Sladek, a professor of cell biology, who led the research project. “Both are important and we want to keep an appropriate balance between them in our gut by avoiding foods that would disrupt this balance and consuming foods that help preserve it. What these foods are is our next focus in the lab.”

    The intestine is the only adult tissue in the body that expresses both P1 and P2. Sladek and her team have shown for the first time that these isoforms perform non-redundant functions in the intestine and are relevant to colitis and colitis-associated colon cancer.

    “Our study also suggests that finding a drug to stabilize one isoform should be more effective than targeting both isoforms for treating colitis and colon cancer,” said Karthikeyani Chellappa, the first author of the research paper and a former postdoctoral researcher in Sladek’s lab.

    Sladek explained that the colonic epithelial surface has finger-like invaginations (into the colonic wall) called colonic crypts that house stem cells at their base. These stem cells help regenerate new epithelial cells that continuously migrate up towards the surface, thus ensuring complete renewal of the intestinal lining every three-five days.

    The researchers observed that the P1-positive cells were found in the surface lining and the top portion of the crypt (green in the accompanying image) while P2-positive cells were mostly in the proliferative compartment in the lower half of the crypt (proliferation marker is red in the image.) Further, when transgenic mice – genetically engineered to have only either P1 or P2 – were subjected to a carcinogen and, subsequently, to an irritant to stress the epithelial lining of the colon, the researchers found that the P1 mice showed fewer tumors than wildtype control mice. When treated with irritant alone, these mice were resistant to colitis. In sharp contrast, mice with only P2 showed more tumors and were much more susceptible to colitis.

    The researchers explain these findings by invoking the “barrier function” – a mucosal barrier, generated by the colon’s epithelial cells, that prevents bacteria in the gut from entering the body. In the case of P1 mice, this barrier function was enhanced. The P2 mice, on the other hand, showed a compromised barrier function, presumably allowing bacteria to pass through.

    Next, the researchers examined genes expressed in the P1 and P2 mice. They found that RELM-beta, a cytokine (a signaling molecule of the immune system) expressed in the gastrointestinal tract and implicated in colitis, was expressed far more in the P2 mice than the P1 mice.

    “This makes sense since a reduced barrier function means bacteria can go across the barrier, which activates RELM-beta,” Sladek said. “We also found that the P2 protein transcribes RELM-beta more effectively than the P1 protein.”

    Next, Poonamjot Deol, an assistant project scientist in Sladek’s lab and the second author of the eLife study, will lead a project aimed at understanding how diet affects the distribution of P1 and P2 in the gut. She and others in the lab also plan to investigate how obesity and colitis may be linked. (Diet studies performed in Sladek’s lab in the past illustrated soybean oil’s adverse effect on obesity.)

    “In the case of colitis, could soybean oil be playing a part in allowing bacteria to get across the barrier function?” Deol said. “We do not know. We know its detrimental effect on obesity. But more research needs to be done where colitis is concerned.”

    Sladek, Chellappa and Deol were joined in the research by; Jane R. Evans, a staff research associate; Linh M. Vuong, a postdoctoral fellow; as well as Gang Chen, Eugene Bolotin, Christian Lytle and Meera G. Nair – all at UCR; and Nadege Briançon, formerly at the Pasteur Institute.

    The research was supported by a grant to Sladek from the National Institutes of Health (NIH 5R01DK053892).

    *Science paper:
    Opposing roles of nuclear receptor HNF4α isoforms in colitis and colitis-associated colon cancer

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    UC Riverside Campus

    The University of California, Riverside is one of 10 universities within the prestigious University of California system, and the only UC located in Inland Southern California.

    Widely recognized as one of the most ethnically diverse research universities in the nation, UCR’s current enrollment is more than 21,000 students, with a goal of 25,000 students by 2020. The campus is in the midst of a tremendous growth spurt with new and remodeled facilities coming on-line on a regular basis.

    We are located approximately 50 miles east of downtown Los Angeles. UCR is also within easy driving distance of dozens of major cultural and recreational sites, as well as desert, mountain and coastal destinations.

     
  • richardmitnick 5:10 pm on March 29, 2016 Permalink | Reply
    Tags: , , UC Riverside   

    From UCR: “Scientists Unlock Genetic Secret that Could Help Fight Malaria” 

    UC Riverside bloc

    UC Riverside

    March 29, 2016
    Sean Nealon

    UC Riverside assistant professor is among researchers that isolated the gene believed to determine whether a mosquito is male

    1
    Researchers have unlocked a genetic mystery surrounding the Anopheles gambiae mosquito species. Photo credit: James Gathany, Centers for Disease Control and Prevention’s Public Health Image Library

    A group of scientists, including one from the University of California, Riverside, have discovered a long-hypothesized male determining gene in the mosquito species that carries malaria, laying the groundwork for the development of strategies that could help control the disease.

    In many species, including mosquitoes, Y chromosomes control essential male functions, including sex determination and fertility. However, knowledge of Y chromosome genetic sequences is limited to a few organisms.

    The discovery of the putative male-determining gene, which was outlined in a paper published online Monday (March 28) in the journal Proceedings of the National Academies of Sciences, provides researchers with a long-awaited foundation for studying male mosquito biology.

    This is significant because male mosquitoes offer the potential to develop novel vector control strategies to combat diseases, such as malaria and the zika and dengue viruses, because males do not feed on blood or transmit diseases. (The African malaria-carrying mosquito, Anopheles gambiae, is different than the mosquito that carries zika and dengue, but similar control strategies could be used to fight both species.)

    One vector control method under development involves genetic modification of the mosquito to bias the population sex ratio toward males, which do not bite, with the goal of reducing or eliminating the population. This and other control methods have received a lot of attention recently because of the spread of zika virus.

    Modeling has shown that the most efficient means for genetic modification of mosquitoes is engineering a driving Y chromosome. A molecular-level understanding of the Y-chromosome of the malaria mosquito, as described in the just-published paper, is important to inform and optimize such a strategy.

    The paper, “Radical remodeling of the Y chromosome in a recent radiation of malaria mosquitoes,” was co-authored by 28 scientists from four countries and four universities in the United States. Omar Akbari, an assistant professor of entomology at UC Riverside and a member of the university’s Institute for Integrative Genome Biology, is one of the authors.

    While the genome of Anopheles gambiae was sequenced 13 years ago, the Y chromosome portion of it was never successfully assembled.

    The researchers who published the paper in the Proceedings of the National Academies of Sciences used multiple genome sequencing techniques, including single-molecule sequencing and Illumina-based sex-specific transcriptional profiling, as well as whole-genome sequencing, to identify an extensive dataset of Y chromosome sequences and explore their organization and evolution in Anopheles gambiae complex, a group of at least seven morphologically indistinguishable species of mosquitos in the genus Anopheles which contain some of the most important vectors of human malaria.

    They found only one gene, known as YG2, which is exclusive to the Y chromosome across the species complex, and thus is a possible male-determining gene.

    The science team:
    Authors

    Andrew Brantley Hall
    aThe Interdisciplinary PhD Program in Genetics, Bioinformatics, and Computational Biology, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061;
    Philippos-Aris Papathanos
    bSection of Genomics and Genetics, Department of Experimental Medicine, University of Perugia, 06132 Perugia, Italy;
    cDepartment of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom;
    Atashi Sharma
    dDepartment of Entomology, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061;
    Changde Cheng
    eEck Institute for Global Health, University of Notre Dame, Notre Dame, IN 46556;
    fDepartment of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556;
    Omar S. Akbari
    gDepartment of Entomology, Riverside Center for Disease Vector Research, Institute for Integrative Genome Biology, University of California, Riverside, CA 92521;
    Lauren Assour
    hDepartment of Computer Science and Engineering, University of Notre Dame, Notre Dame, IN 46556;
    Nicholas H. Bergman
    iNational Biodefense Analysis and Countermeasures Center, Frederick, MD 21702;
    Alessia Cagnetti
    bSection of Genomics and Genetics, Department of Experimental Medicine, University of Perugia, 06132 Perugia, Italy;
    Andrea Crisanti
    bSection of Genomics and Genetics, Department of Experimental Medicine, University of Perugia, 06132 Perugia, Italy;
    cDepartment of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom;
    Tania Dottorini
    cDepartment of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom;
    Elisa Fiorentini
    cDepartment of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom;
    Roberto Galizi
    cDepartment of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom;
    Jonathan Hnath
    iNational Biodefense Analysis and Countermeasures Center, Frederick, MD 21702;
    Xiaofang Jiang
    aThe Interdisciplinary PhD Program in Genetics, Bioinformatics, and Computational Biology, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061;
    Sergey Koren
    jGenome Informatics Section, Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892;
    Tony Nolan
    cDepartment of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom;
    Diane Radune
    iNational Biodefense Analysis and Countermeasures Center, Frederick, MD 21702;
    Maria V. Sharakhova
    dDepartment of Entomology, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061;
    kLaboratory of Evolutionary Cytogenetics, Tomsk State University, Tomsk 634050, Russia;
    Aaron Steele
    hDepartment of Computer Science and Engineering, University of Notre Dame, Notre Dame, IN 46556;
    Vladimir A. Timoshevskiy
    dDepartment of Entomology, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061;
    Nikolai Windbichler
    cDepartment of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom;
    Simo Zhang
    lSchool of Informatics and Computing, Indiana University, Bloomington, IN 47405;
    Matthew W. Hahn
    lSchool of Informatics and Computing, Indiana University, Bloomington, IN 47405;
    mDepartment of Biology, Indiana University, Bloomington, IN 47405;

    View ORCID profile for Matthew W. Hahn
    Adam M. Phillippy
    jGenome Informatics Section, Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892;

    View ORCID profile for Adam M. Phillippy
    Scott J. Emrich
    eEck Institute for Global Health, University of Notre Dame, Notre Dame, IN 46556;
    hDepartment of Computer Science and Engineering, University of Notre Dame, Notre Dame, IN 46556;
    Igor V. Sharakhov
    aThe Interdisciplinary PhD Program in Genetics, Bioinformatics, and Computational Biology, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061;
    dDepartment of Entomology, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061;
    kLaboratory of Evolutionary Cytogenetics, Tomsk State University, Tomsk 634050, Russia;
    Zhijian Jake Tu
    aThe Interdisciplinary PhD Program in Genetics, Bioinformatics, and Computational Biology, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061;
    nDepartment of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061
    Nora J. Besansky
    eEck Institute for Global Health, University of Notre Dame, Notre Dame, IN 46556;
    fDepartment of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556;

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    UC Riverside Campus

    The University of California, Riverside is one of 10 universities within the prestigious University of California system, and the only UC located in Inland Southern California.

    Widely recognized as one of the most ethnically diverse research universities in the nation, UCR’s current enrollment is more than 21,000 students, with a goal of 25,000 students by 2020. The campus is in the midst of a tremendous growth spurt with new and remodeled facilities coming on-line on a regular basis.

    We are located approximately 50 miles east of downtown Los Angeles. UCR is also within easy driving distance of dozens of major cultural and recreational sites, as well as desert, mountain and coastal destinations.

     
  • richardmitnick 5:49 pm on March 22, 2016 Permalink | Reply
    Tags: , , Tracing Star Formation Rates in Distant Galaxies, UC Riverside   

    From UC Riverside: “Tracing Star Formation Rates in Distant Galaxies” 

    UC Riverside bloc

    UC Riverside

    March 22, 2016
    Sean Nealon

    radio galaxies gravitationally lensed by a very large foreground galaxy cluster Hubble
    Radio galaxies gravitationally lensed by a very large foreground galaxy cluster. Hubble

    NASA/ESA Hubble Telescope
    NASA/ESA Hubble Telescope

    When we think of a galaxy the first thing that comes to our minds is an assembly of stars. Indeed, the stars of a galaxy are one of its most important characteristics.

    To understand the physics of the evolution and formation of galaxies it is crucial to know at what rate galaxies form stars, referred to as the star-formation rate. This rate shows how active a galaxy is: young galaxies with large amounts of gas form many stars, while red and old galaxies that have depleted their gas reservoirs do not actively form stars.

    Cosmological events such as mergers between galaxies can also boost the star-formation rate. However, unless we are observing the Milky Way and very close local galaxies, we cannot detect individual stars and star-forming regions in distant galaxies. Therefore, we need to rely on global observable characteristics to estimate the star-formation rate of galaxies located far away.

    The best way to fully understand the properties of galaxies is by studying them at a broad range of wavelengths; as each type of light is emitted from a different actor in a galaxy. For example, the ultraviolet light comes from the youngest and most massive stars, while the optical and near-infrared continuum light is emitted mostly from more evolved stars. Infrared light, on the other hand, traces dust in a galaxy, and emission lines that are detected in spectral lines trace the gas clouds.

    In paper published online March 22, a group of researchers, led by Irene Shivaei, a University of California, Riverside graduate student, observed 17 bright distant galaxies with the MOSFIRE high-resolution near-infrared spectrometer at the W. M. Keck Observatory telescopes. Then, they combined the spectra with infrared images of the Spitzer Space Telescope, the Herschel Space Observatory, and optical images of the Hubble Space Telescope, to create a complete multi-wavelength picture of their galaxies: from rest-frame ultraviolet to rest-frame far-infrared.

    Keck MOSFIRE
    Keck MOSFIRE

    Keck Observatory
    Keck Observatory

    NASA/Spitzer Telescope
    NASA/Spitzer Telescope

    ESA/Herschel
    ESA/Herschel

    They looked at various observables that are commonly used to estimate the star-formation rates in galaxies and compare them with each other. These star-formation rate estimators include the ultraviolet light that is emitted from young stars, the infrared light that shows how much of the ultraviolet light was absorbed by dust, and the nebular emission lines that are caused by young stars making the clouds of gas around them glow and radiate. These diagnostics have been observed and tested for local galaxies extensively in the past decade, but for distant galaxies it is challenging to acquire complete multi-wavelength datasets.

    This study makes the first direct comparison between the optical emission line and the ultraviolet and infrared tracers of star formation and indicates that, despite the underlying uncertainties, astronomers can trust the nebular emission lines as robust indicators of the star-formation rate and the amount of light that is obscured by dust in distant galaxies.

    These results help to build the foundations of galaxy evolution studies, in other words, help predict a physical quantity (in this case, the star-formation rate) of a distant galaxy from the light that our telescopes capture.

    This analysis is part of the MOSFIRE Deep Evolution Field (MOSDEF) survey , which is conducted by astronomers at UC Riverside, UCLA, UC Berkeley, UC San Diego. The MOSDEF team uses the MOSFIRE spectrometer on the the W. M. Keck Observatory telescopes to obtain spectra for many galaxies that are located at 1.5 to 4.5 billion years after the Big Bang, the interval in which the universe formed the highest amount of stars in its history. The goal of the survey is to study the stellar, gaseous, and blackhole content of galaxies at this important era in the history of the universe.

    The paper was published in The Astrophysical Journal Letters. It was authored by researchers at UC Riverside, UCLA, UC Berkeley, UC San Diego, Harvard University and the National Optical Astronomy Observatory in Tuscon, Ariz.

    Besides Shivaei, the other UC Riverside researchers were: Naveen Reddy, an assistant professor; Brian Siana, an assistant professor; William Freeman, a graduate student working with Siana; and Bahram Mobasher, a professor.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    UC Riverside Campus

    The University of California, Riverside is one of 10 universities within the prestigious University of California system, and the only UC located in Inland Southern California.

    Widely recognized as one of the most ethnically diverse research universities in the nation, UCR’s current enrollment is more than 21,000 students, with a goal of 25,000 students by 2020. The campus is in the midst of a tremendous growth spurt with new and remodeled facilities coming on-line on a regular basis.

    We are located approximately 50 miles east of downtown Los Angeles. UCR is also within easy driving distance of dozens of major cultural and recreational sites, as well as desert, mountain and coastal destinations.

     
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