Just four percent of galaxies have neighbors like the Milky Way

ScienceDaily (May 23, 2011) — How unique is the Milky Way?

To find out, a group of researchers led by Stanford University astrophysicist Risa Wechsler compared the Milky Way to similar galaxies and found that just four percent are like the galaxy Earth calls home.

"We are interested in how the Milky Way fits into the broader context of the universe," said Wechsler. "This research helps us understand whether our galaxy is typical or not, and may provide clues to its formation history."

The research team compared the Milky Way to similar galaxies in terms of luminosity--a measure of how much light is emitted--and distance to other bright galaxies. They found galaxies that have two satellites that are as bright and close by as the Milky Way's two closest satellites, the Large and Small Magellanic Clouds, are rare.

Published in the May 20 issue of the Astrophysical Journal, the findings are based on analyses of data collected from the Sloan Digital Sky Survey (SDSS). The work is the first of three papers that study the properties of the Milky Way's two most massive satellites.

Supported in part by the National Science Foundation (NSF), the SDSS is the most extensive survey of the optical sky performed to date.

In more than eight years of operations, SDSS has obtained images covering more than a quarter of the sky, and created 3-dimensional maps containing more than 930,000 galaxies and 120,000 quasars. For this analysis, Wechsler's group studied more than 20,000 galaxies with properties similar to the Milky Way and investigated the galaxies surrounding these Milky Way "twins," to create a "census" of galaxies similar to the Milky Way in the universe.

The work represents one of the most extensive studies of this kind ever performed.

Scientists can also compare the SDSS data to galaxies simulated by a computer model. Since they are currently unable to see all the way back to the Big Bang, this is one way researchers are trying to understand how the universe as we see it today began.

In order to learn more about possible conditions in the early universe, the group performed computer simulations to recreate the universe from specific sets of starting conditions. Then they compared their simulations to the SDSS data set. In this way, the group was able to test different theories of galaxy formation to determine whether or not each would result in a universe that matches what we see today. The results of their simulation matched the result found in the SDSS data set: just four percent of the simulated galaxies had two satellites like the Magellanic Clouds.

"This is an excellent example of data-enabled science," said Nigel Sharp, of NSF's Division of Astronomical Sciences. "Comparing the 'fake' and 'real' Universes is how we discriminate between successful and unsuccessful theories. This work interconnects three of the four legs of science: theory, observation and simulation, for a powerful scientific result."

Their results also lend support to a leading theory of galaxy formation called the Cold Dark Matter (CDM) theory. This theory provides what many consider to be the simplest explanation for the arrangement of galaxies throughout the universe following the Big Bang. It assumes that most of the matter in the Universe consists of material that cannot be observed by its electromagnetic radiation (dark) and whose constituent particles move slowly (cold). Dark matter, an invisible and exotic material of unknown composition, is believed to influence the distribution of galaxies in space and the overall expansion of the universe. The rareness of this aspect of the Milky Way may provide clues to its formation history.

"Because the presence of two galaxies like the Magellanic Clouds is unusual, we can use them to learn more about our own galaxy," said Wechsler. Using their simulation, the team identified a sample of simulated galaxies that had satellites matching the Milky Way's in terms of their locations and speeds.

"The combination of large surveys of the sky like the SDSS and large samples of simulated galaxies provides a new opportunity to learn about the place of our galaxy in the Universe," said Wechsler. "Future surveys will allow us to extend this study to even dimmer satellite galaxies, to build a full picture of the formation of our galaxy."

The theoretical and numerical work that produced the simulations used as a comparison for the SDSS data were supported by an award funded under the American Recovery and Reinvestment Act of 2009.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by National Science Foundation.

Journal Reference:

Lulu Liu, Brian F. Gerke, Risa H. Wechsler, Peter S. Behroozi, Michael T. Busha. How Common Are the Magellanic Clouds? The Astrophysical Journal, 2011; 733 (1): 62 DOI: 10.1088/0004-637X/733/1/62

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New solar product captures up to 95 percent of light energy

ScienceDaily (May 17, 2011) — Efficiency is a problem with today's solar panels; they only collect about 20 percent of available light. Now, a University of Missouri engineer has developed a flexible solar sheet that captures more than 90 percent of available light, and he plans to make prototypes available to consumers within the next five years.

Patrick Pinhero, an associate professor in the MU Chemical Engineering Department, says energy generated using traditional photovoltaic (PV) methods of solar collection is inefficient and neglects much of the available solar electromagnetic (sunlight) spectrum. The device his team has developed -- essentially a thin, moldable sheet of small antennas called nantenna -- can harvest the heat from industrial processes and convert it into usable electricity. Their ambition is to extend this concept to a direct solar facing nantenna device capable of collecting solar irradiation in the near infrared and optical regions of the solar spectrum.

Working with his former team at the Idaho National Laboratory and Garrett Moddel, an electrical engineering professor at the University of Colorado, Pinhero and his team have now developed a way to extract electricity from the collected heat and sunlight using special high-speed electrical circuitry. This team also partners with Dennis Slafer of MicroContinuum, Inc., of Cambridge, Mass., to immediately port laboratory bench-scale technologies into manufacturable devices that can be inexpensively mass-produced.

"Our overall goal is to collect and utilize as much solar energy as is theoretically possible and bring it to the commercial market in an inexpensive package that is accessible to everyone," Pinhero said. "If successful, this product will put us orders of magnitudes ahead of the current solar energy technologies we have available to us today."

As part of a rollout plan, the team is securing funding from the U.S. Department of Energy and private investors. The second phase features an energy-harvesting device for existing industrial infrastructure, including heat-process factories and solar farms.

Within five years, the research team believes they will have a product that complements conventional PV solar panels. Because it's a flexible film, Pinhero believes it could be incorporated into roof shingle products, or be custom-made to power vehicles.

Once the funding is secure, Pinhero envisions several commercial product spin-offs, including infrared (IR) detection. These include improved contraband-identifying products for airports and the military, optical computing, and infrared line-of-sight telecommunications.

A study on the design and manufacturing process was published in the Journal of Solar Energy Engineering.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by University of Missouri-Columbia, via EurekAlert!, a service of AAAS.

Journal Reference:

D. K. Kotter, S. D. Novack, W. D. Slafer, P. J. Pinhero. Theory and Manufacturing Processes of Solar Nanoantenna Electromagnetic Collectors. Journal of Solar Energy Engineering, 2010; 132 (1): 011014 DOI: 10.1115/1.4000577

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

New solar product captures up to 95 percent of light energy

ScienceDaily (May 17, 2011) — Efficiency is a problem with today's solar panels; they only collect about 20 percent of available light. Now, a University of Missouri engineer has developed a flexible solar sheet that captures more than 90 percent of available light, and he plans to make prototypes available to consumers within the next five years.

Patrick Pinhero, an associate professor in the MU Chemical Engineering Department, says energy generated using traditional photovoltaic (PV) methods of solar collection is inefficient and neglects much of the available solar electromagnetic (sunlight) spectrum. The device his team has developed -- essentially a thin, moldable sheet of small antennas called nantenna -- can harvest the heat from industrial processes and convert it into usable electricity. Their ambition is to extend this concept to a direct solar facing nantenna device capable of collecting solar irradiation in the near infrared and optical regions of the solar spectrum.

Working with his former team at the Idaho National Laboratory and Garrett Moddel, an electrical engineering professor at the University of Colorado, Pinhero and his team have now developed a way to extract electricity from the collected heat and sunlight using special high-speed electrical circuitry. This team also partners with Dennis Slafer of MicroContinuum, Inc., of Cambridge, Mass., to immediately port laboratory bench-scale technologies into manufacturable devices that can be inexpensively mass-produced.

"Our overall goal is to collect and utilize as much solar energy as is theoretically possible and bring it to the commercial market in an inexpensive package that is accessible to everyone," Pinhero said. "If successful, this product will put us orders of magnitudes ahead of the current solar energy technologies we have available to us today."

As part of a rollout plan, the team is securing funding from the U.S. Department of Energy and private investors. The second phase features an energy-harvesting device for existing industrial infrastructure, including heat-process factories and solar farms.

Within five years, the research team believes they will have a product that complements conventional PV solar panels. Because it's a flexible film, Pinhero believes it could be incorporated into roof shingle products, or be custom-made to power vehicles.

Once the funding is secure, Pinhero envisions several commercial product spin-offs, including infrared (IR) detection. These include improved contraband-identifying products for airports and the military, optical computing, and infrared line-of-sight telecommunications.

A study on the design and manufacturing process was published in the Journal of Solar Energy Engineering.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by University of Missouri-Columbia, via EurekAlert!, a service of AAAS.

Journal Reference:

D. K. Kotter, S. D. Novack, W. D. Slafer, P. J. Pinhero. Theory and Manufacturing Processes of Solar Nanoantenna Electromagnetic Collectors. Journal of Solar Energy Engineering, 2010; 132 (1): 011014 DOI: 10.1115/1.4000577

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

Infection control violations at 15 percent of US nursing homes

ScienceDaily (May 3, 2011) — Fifteen percent of U.S. nursing homes receive deficiency citations for infection control per year, according to a new study published in the May issue of the American Journal of Infection Control, the official publication of APIC -- the Association for Professionals in Infection Control and Epidemiology.

Conducted by a team of researchers at the University of Pittsburgh's Graduate School of Public Health, the study analyzed deficiency citation data collected for the purpose of Medicare/Medicaid certification between 2000 and 2007, representing approximately 16,000 nursing homes per year and a panel of roughly 100,000 observations. The records analyzed represent 96 percent of all U.S. nursing home facilities. The team discovered a strong correlation between low staffing levels and the receipt of an infection control deficiency citation.

Infections are the leading cause of morbidity and mortality in nursing homes, responsible for nearly 400,000 deaths per year. Although this has been the focus of mainstream media attention, very little empirical research has been conducted on the subject.

The Centers for Medicare and Medicaid Services (CMS) requires that nursing homes be certified before receiving reimbursement for Medicare and/or Medicaid residents. As part of this certification process, facilities that do not meet certain standards are issued deficiency citations. This study examined the deficiency citation for infection control requirements known as the F-Tag 441.

"Our analysis may provide some clues as to the reason for the persistent infection control problems in nursing homes," state the authors. "Most significantly, the issue of staffing is very prominent in our findings; that is, for all three caregivers examined (i.e., nurse aides, LPNs and RNs) low staffing levels are associated with F-Tag 441 citations. With low staffing levels, these caregivers are likely hurried and may skimp on infection control measures, such as hand hygiene."

The authors conclude, "The high number of deficiency citations for infection control problems identified in this study suggests the need for increased emphasis on these programs in nursing homes to protect vulnerable elders."

A number of states have enacted legislation that applies to infection prevention practices in long-term care facilities. Illinois is poised to pass legislation requiring an infection preventionist in each skilled nursing facility.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Elsevier Health Sciences, via EurekAlert!, a service of AAAS.

Journal Reference:

Nicholas G. Castle, Laura M. Wagner, Jamie C. Ferguson-Rome, Aiju Men, Steven M. Handler. Nursing home deficiency citations for infection control. American Journal of Infection Control, 2011; 39 (4): 263 DOI: 10.1016/j.ajic.2010.12.010

Note: If no author is given, the source is cited instead.

Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of ScienceDaily or its staff.

View the original article here