Computer engineers at the University of California at Berkeley have found a way to reduce the minimum voltage required to store a charge in a capacitor--an electron-storing device that works somewhat like a battery--paving the way for ultra-low-power computing. This is a result of a project started in 2008 and led by Asif Khan, a UC Berkeley electrical engineering graduate student, and Sayeef Salahuddin, a UC Berkeley assistant professor of electrical engineering.
The engineers took advantage of ferroelectrics, a class of materials that can hold both positive and negative electric charges, even when there's no voltage applied. On top of that, the electrical polarization in ferroelectrics can be reversed with an external electric field.
The team was able to demonstrate that when a capacitor made of ferroelectric-based materials was paired with an electric insulator, the charge accumulated for a given voltage could be amplified in a phenomenon called "negative capacitance." This means you can create a charge that would normally require a higher voltage. And this, when applied to transistors--the on-off switch components that generate the zeros and ones that are the core of binary computing used in all personal computers--would translate into lower minimum voltage required to operate a computer processor.
Traditionally, a computer's processor (or chip) is made of transistors. The more transistors a chip has, the more processing power it offers. When first introduced in the 1970s, a processor had about a few thousand transistors. Moore's Law speculates that the number of transistors that could be squeezed onto a computer chip would double every two years. A modern processor now has billions of transistors.
While Moore's law held for many years, the number of transistors that can be put on a chip has slowly plateaued since about 2005. This is not because engineers can't reduce the transistors' size anymore, but because the reduced size doesn't translate into a proportional decrease in the overall power required to operate the chip. Due to the fundamental physics of a transistor's operation, its minimum required power supply has remained at 1 volt for about 10 years. Lower than that, the current is not strong enough to create a charge to change the transistor between its on and off states.
This constant power intake translates into a rather constant amount of heat generated by a transistor, regardless of its size. This means the more of them you put on a chip, the hotter the processor gets and the harder it is for the engineers to find a way to efficiently dissipate the heat fast enough. At some point, they can't keep shrinking the transistors without risking a fire hazard.
Salahuddin and his team proposed a solution to modify current transistors so they incorporate ferroelectric materials in the design. Potentially, similar to the case of the capacitor, this change would help create a sufficient charge from a smaller voltage and therefore would let engineers make transistors that generate less heat, which means they can continue to shrink their size further.
In layman's terms, this is similar to making a car run more efficiently so that its engine produces the same amount of horsepower and torque with less gasoline and won't become overheated at high speeds and during long stretches of operation. Apart from transistors, Salahuddin said ferroelectric material can also be used in other applications, such as system memory, energy storage devices, electric car chargers, and other electronics.
2011年9月12日星期一
2011年9月8日星期四
Protect Your Pets From Lyme Disease
For lively pups, the outdoors serves as a playground -- but it can also serve as a breeding ground for deadly disease.
According to the American Lyme Disease Foundation, the deer tick is responsible for infecting dogs with Lyme disease every year, irrespective of season.
“Although the deer tick is number one for Lyme in animals, the brown dog tick can also transmit Lyme to dogs,” Philip E. Block, a veterinarian at the Redding Veterinary Hospital explained.
Regardless of the type of tick that infects dogs, they can all cause symptoms that will be noticeable to pet owners. If a canine is infected with Lyme, there are signs that will be more recognizable than others. Swollen joints, loss of appetite and lameness are a few that the ALDA wants pet owners to look out for.
“Believe it or not, dogs don’t get the bullseye like people do,” Block said. “Sometimes you will see a swelling or a limp.”
If you’re wondering how Lyme will affect your dog’s energy level, you can expect that they won’t be playing fetch too enthusiastically.
“Most dogs with Lyme don’t want to do a lot,” Block said. “They just seem off – lethargic and tired."
When pets are brought into the Redding Veterinary Hospital, Block has their antibodies tested. He performs a test known as the 4DX snap test. This test detects heartworm, Lyme disease, anaplasma and Ehrlichia.
“If it comes back positive for a dog who has never had it before, we will treat the dog and then we will focus on prevention.”
Lyme disease is more common in canines than in people, according to Block. But they are also more treatable than humans, he said.
“I have a lot of [human] clients that have Lyme and can’t seem to get rid of it,” Block said.
"It ends up being the gift that never stops giving,” he said.
When treating a dog, Block gives them a 28-day treatment. After two days, he often sees a significant difference in the behavior of the animals. One of the most effective Lyme treatments that Block uses is the new Next Generation Lyme vaccine. The official name of the vaccine is Intervet Lyme vaccine. Block also recommends the use of Advantix.
“We use the Advantix to paralyze the jaw of the tick so it doesn’t transmit to people,” Block said.
Although dogs cannot directly transmit Lyme disease to humans, Jennifer Reid and Karen Gaudian of the Ridgefield Lyme Disease Task Force recommend that people do not sleep with their pets.
“Don’t sleep with your pets,” Gaudian warns.
“They can bring the ticks in from outside and into your home,” Reid added. “We recommend that people have their yards sprayed so that it reduces the risk of pets bringing ticks into the home, as well as the amount of ticks on the property” she said.
Although Lyme is easily treatable in dogs, once they bring an infected tick home to their owners, they may no longer be able to count on an active family that can play with them.
“Lyme is a lot easier to treat in dogs rather than people,” Block warned.
Having a yard sprayed is a preventative measure that is usually only taken in the summer months, according to the LDTF, but Block warns that just like people, pets can contract Lyme disease during all seasons, so preventative measures should never take a back seat.
“We see Lyme year round,” he said. “The only time we don’t is when there is standing snow on the ground. Snow can actually act as a good insulator for ticks.”
Block recommends that dog owners use topical treatments like Advantix that contain Permethrin, as well as performing daily tick checks on both dogs and family members. The topical treatments repel ticks as well as treat the infection of a tick attachment, according to Block.
According to the American Lyme Disease Foundation, the deer tick is responsible for infecting dogs with Lyme disease every year, irrespective of season.
“Although the deer tick is number one for Lyme in animals, the brown dog tick can also transmit Lyme to dogs,” Philip E. Block, a veterinarian at the Redding Veterinary Hospital explained.
Regardless of the type of tick that infects dogs, they can all cause symptoms that will be noticeable to pet owners. If a canine is infected with Lyme, there are signs that will be more recognizable than others. Swollen joints, loss of appetite and lameness are a few that the ALDA wants pet owners to look out for.
“Believe it or not, dogs don’t get the bullseye like people do,” Block said. “Sometimes you will see a swelling or a limp.”
If you’re wondering how Lyme will affect your dog’s energy level, you can expect that they won’t be playing fetch too enthusiastically.
“Most dogs with Lyme don’t want to do a lot,” Block said. “They just seem off – lethargic and tired."
When pets are brought into the Redding Veterinary Hospital, Block has their antibodies tested. He performs a test known as the 4DX snap test. This test detects heartworm, Lyme disease, anaplasma and Ehrlichia.
“If it comes back positive for a dog who has never had it before, we will treat the dog and then we will focus on prevention.”
Lyme disease is more common in canines than in people, according to Block. But they are also more treatable than humans, he said.
“I have a lot of [human] clients that have Lyme and can’t seem to get rid of it,” Block said.
"It ends up being the gift that never stops giving,” he said.
When treating a dog, Block gives them a 28-day treatment. After two days, he often sees a significant difference in the behavior of the animals. One of the most effective Lyme treatments that Block uses is the new Next Generation Lyme vaccine. The official name of the vaccine is Intervet Lyme vaccine. Block also recommends the use of Advantix.
“We use the Advantix to paralyze the jaw of the tick so it doesn’t transmit to people,” Block said.
Although dogs cannot directly transmit Lyme disease to humans, Jennifer Reid and Karen Gaudian of the Ridgefield Lyme Disease Task Force recommend that people do not sleep with their pets.
“Don’t sleep with your pets,” Gaudian warns.
“They can bring the ticks in from outside and into your home,” Reid added. “We recommend that people have their yards sprayed so that it reduces the risk of pets bringing ticks into the home, as well as the amount of ticks on the property” she said.
Although Lyme is easily treatable in dogs, once they bring an infected tick home to their owners, they may no longer be able to count on an active family that can play with them.
“Lyme is a lot easier to treat in dogs rather than people,” Block warned.
Having a yard sprayed is a preventative measure that is usually only taken in the summer months, according to the LDTF, but Block warns that just like people, pets can contract Lyme disease during all seasons, so preventative measures should never take a back seat.
“We see Lyme year round,” he said. “The only time we don’t is when there is standing snow on the ground. Snow can actually act as a good insulator for ticks.”
Block recommends that dog owners use topical treatments like Advantix that contain Permethrin, as well as performing daily tick checks on both dogs and family members. The topical treatments repel ticks as well as treat the infection of a tick attachment, according to Block.
2011年9月7日星期三
Athenaeum Renovated for First Time Since Its Opening
In addition to the opening of Claremont McKenna College’s new Kravis Center, this summer saw a complete renovation of the Athenaeum by IA Interior Architects thanks to a $4.5 million allotment by the Board of Trustees. The building had not been renovated since its opening in 1983 and had only experienced one carpet change until its complete infrastructural and design makeover this summer. Needless to say, the time had come for a facelift, and a significant one at that.
The plan, first discussed in a 2009 trustee meeting, was put into motion on commencement day of last year, and the building was ready to use just before the Parents Dinner on August 25th, 2011. Athenaeum manager David Edwards hopes the renovations will “bring a sleek, new look” and update the structure with which the building was originally created.
The renovation focused on design, technology, and energy use, explained Frank Perri, CMC’s Director of Construction. The design component is immediately visible in the building’s new furnishings, which include three new flat screen TV’s, custom designed chairs in the dining hall, new carpets, limestone floors, and an increase in the number of chandeliers in the dining room from 4 to 24.
The Athenaeum now features completely refurbished bathrooms with automated systems; a gas fireplace in the library; a completely new kitchen line including a new freezer, dishwasher, and refrigerator; increased wireless capacity; and improved acoustics thanks to a new AV system and the installation of transparent acoustic enhancing cloth in the lobby and dining rooms. Hinges were added to the large window in the dining hall, allowing them pivot and open the room to the quad outdoors.
Energy conservation was a large part of the decisions made in the Athenaeum renovation. The new kitchen appliances save energy to be sure, but three flat screen TVs and a gas fireplace can’t help much on the energy expenditure front. Each of the 24 new chandeliers in the main dining room have Energy Star and energy efficient certifications, making them an environmentally-friendly addition to the renovation. The building is now air conditioned by the Kravis Center, which pumps chilled water that also feeds the air conditioning systems for Roberts North and South, Adams Hall, and the Emmett Student Center. The roof’s rotted wood was replaced and harvested where possible to make way for a foam roof that acts as both a waterproof cover and an insulator. A composter was added to the kitchen, and the bathrooms have been remodeled with water efficient and low flow sinks.
The new Ath is refurbished, modernized, and ready for another year of speakers and students. With input from the board of trustees, the student Athenaeum committee, and Athenaeum employees, the final project is, as Perri puts it, one of which “everyone involved is proud.” A world class facility for world class speakers.
The plan, first discussed in a 2009 trustee meeting, was put into motion on commencement day of last year, and the building was ready to use just before the Parents Dinner on August 25th, 2011. Athenaeum manager David Edwards hopes the renovations will “bring a sleek, new look” and update the structure with which the building was originally created.
The renovation focused on design, technology, and energy use, explained Frank Perri, CMC’s Director of Construction. The design component is immediately visible in the building’s new furnishings, which include three new flat screen TV’s, custom designed chairs in the dining hall, new carpets, limestone floors, and an increase in the number of chandeliers in the dining room from 4 to 24.
The Athenaeum now features completely refurbished bathrooms with automated systems; a gas fireplace in the library; a completely new kitchen line including a new freezer, dishwasher, and refrigerator; increased wireless capacity; and improved acoustics thanks to a new AV system and the installation of transparent acoustic enhancing cloth in the lobby and dining rooms. Hinges were added to the large window in the dining hall, allowing them pivot and open the room to the quad outdoors.
Energy conservation was a large part of the decisions made in the Athenaeum renovation. The new kitchen appliances save energy to be sure, but three flat screen TVs and a gas fireplace can’t help much on the energy expenditure front. Each of the 24 new chandeliers in the main dining room have Energy Star and energy efficient certifications, making them an environmentally-friendly addition to the renovation. The building is now air conditioned by the Kravis Center, which pumps chilled water that also feeds the air conditioning systems for Roberts North and South, Adams Hall, and the Emmett Student Center. The roof’s rotted wood was replaced and harvested where possible to make way for a foam roof that acts as both a waterproof cover and an insulator. A composter was added to the kitchen, and the bathrooms have been remodeled with water efficient and low flow sinks.
The new Ath is refurbished, modernized, and ready for another year of speakers and students. With input from the board of trustees, the student Athenaeum committee, and Athenaeum employees, the final project is, as Perri puts it, one of which “everyone involved is proud.” A world class facility for world class speakers.
2011年9月6日星期二
Your Smart Phone Applies Geometry to Interpret Touch
Touch sensitive screens first appeared on industrial control panels over 20 years ago, but they are now common on personal computers and smart phones.
There are two problems to be solved when designing the system: sensing when the screen is touched and working out where it was touched.
The most common technology is the resistive one, which uses the simple idea of a switch. The outer surface of the screen is covered with three thin layers of different materials.
The first one is metallic, the second a fine gauze made of an insulator and the third a flexible conducting plastic. Finally, the top is coated with a scratch-proof film to prevent damage.
All these layers are so thin that they are almost transparent in ordinary light. That way, it is possible to see the graphics on the screen.
Terminals are connected at one corner of the screen and a small voltage applied between the conducting plastic layer and the metallic film.
Since the two layers are separated by the insulating gauze, no current will flow, but when the screen is touched, the flexible plastic bends and makes contact with the metallic layer below through the open spaces in the gauze.
When the two layers make contact, current flows -- just like in a switch -- and the computer senses that the screen has been touched.
To determine the point that was touched, voltage is measured at the other three corners of the screen.
Since the plastic layer is not a good conductor, the voltage will be proportional to the distance from the respective corner to the point of contact.
It is possible to work out the coordinates of the point of contact by applying triangulation geometry.
Imagine a drawing compass is mounted at the first corner of the screen and then opened to draw an arch whose radius is equal to the distance calculated from the voltage.
Repeat the same drawing from the second and third corners. The three arches will meet at one point on the screen -- the point of contact. This is how the system evaluates the coordinates.
Another common type of touch screen technology applies the principle of capacitance. An electrical capacitor is simply two layers of conductors separated by an insulator.
Thus, the basic design is also in the form of layers. However, the middle layer is made of a continuous insulating material instead of the gauze.
When voltage is applied to the two conducting layers, a uniform electric field is formed between them. Touching the screen distorts this field, thereby changing the voltage.
The change in voltage depends on the location of the distortion. Therefore, by measuring from three corners of the screen, it is possible to triangulate the coordinates of the point of touch.
The major advantage of the capacitance touch screen is that it has no moving parts, making it more durable than the resistive type.
For this reason, it is the preferred design for industrial control panels, touch-sensitive ATM screens and laptop touchpads.
However, while the resistive type responds when touched by any material, the capacitive design can only be operated by bare fingers. Even wearing gloves will inhibit its operation.
There are two problems to be solved when designing the system: sensing when the screen is touched and working out where it was touched.
The most common technology is the resistive one, which uses the simple idea of a switch. The outer surface of the screen is covered with three thin layers of different materials.
The first one is metallic, the second a fine gauze made of an insulator and the third a flexible conducting plastic. Finally, the top is coated with a scratch-proof film to prevent damage.
All these layers are so thin that they are almost transparent in ordinary light. That way, it is possible to see the graphics on the screen.
Terminals are connected at one corner of the screen and a small voltage applied between the conducting plastic layer and the metallic film.
Since the two layers are separated by the insulating gauze, no current will flow, but when the screen is touched, the flexible plastic bends and makes contact with the metallic layer below through the open spaces in the gauze.
When the two layers make contact, current flows -- just like in a switch -- and the computer senses that the screen has been touched.
To determine the point that was touched, voltage is measured at the other three corners of the screen.
Since the plastic layer is not a good conductor, the voltage will be proportional to the distance from the respective corner to the point of contact.
It is possible to work out the coordinates of the point of contact by applying triangulation geometry.
Imagine a drawing compass is mounted at the first corner of the screen and then opened to draw an arch whose radius is equal to the distance calculated from the voltage.
Repeat the same drawing from the second and third corners. The three arches will meet at one point on the screen -- the point of contact. This is how the system evaluates the coordinates.
Another common type of touch screen technology applies the principle of capacitance. An electrical capacitor is simply two layers of conductors separated by an insulator.
Thus, the basic design is also in the form of layers. However, the middle layer is made of a continuous insulating material instead of the gauze.
When voltage is applied to the two conducting layers, a uniform electric field is formed between them. Touching the screen distorts this field, thereby changing the voltage.
The change in voltage depends on the location of the distortion. Therefore, by measuring from three corners of the screen, it is possible to triangulate the coordinates of the point of touch.
The major advantage of the capacitance touch screen is that it has no moving parts, making it more durable than the resistive type.
For this reason, it is the preferred design for industrial control panels, touch-sensitive ATM screens and laptop touchpads.
However, while the resistive type responds when touched by any material, the capacitive design can only be operated by bare fingers. Even wearing gloves will inhibit its operation.
2011年9月5日星期一
Dry conditions, heavy winds spark fires throughout Crossroads
Victoria's dry conditions, low humidity and high winds ignited a series of fires that spread throughout Victoria and surrounding counties Sunday.
"It was a large amount of fires for the day," Victoria Fire Department Battalion Chief Tracy Fox said. "The drought conditions are really what exasperated the fires today."
Firefighters responded to seven emergency fire calls in Victoria throughout the day: one house fire, five grass fires and a boat fire at Stratford Place Apartments. Fire departments around the Crossroads also responded to other grass fires.
A home in the 1900 block of Guadalupe Road was destroyed in a fire, first reported about 12:30 p.m.
Down the road about five miles, fire officials responded to a grass fire about 1 p.m., which sparked near U.S. 87 and Crouch and Menke roads. Fire Marshal Ron Pray said about 100-120 acres caught fire; the cause of the fire is unknown. The fire also damaged a railroad trestle, he said.
A second grass fire ignited on U.S. 87 and Sunray Road about 1:30 p.m., burning about 50 acres of brush. Strong winds downed an electrical wire, which caused the brush to catch fire, Pray said.
The two grass fires forced law enforcement officials to shut down U.S. 87 in both directions for about two hours.
On U.S. 77 and Farm-to-Market 445 and McFaddin Road, a third grass fire started about 2:30 p.m., burning about an acre of land. Fox said the cause is unknown.
A fourth grass fire ignited in the 1000 block of South Main Street about 4:30 p.m., burning about a half acre near a water pumping station. Fox said the cause is unknown.
A house located at 3465 Farm-to-Market Road 446 in Victoria, and about 10 acres of brush caught fire at 5:30 p.m. A resident of the home burning trash in the back yard was unable to contain the flames in the heavy winds. The fire spread to the rear of the home, burning one room and the attic.
A boat caught fire at Stratford Place Apartments, 3207 E. Airline Road. The fire was contained quickly, Pray said. The cause is still under investigation.
Outside the county, two fires occurred in Jackson County on Farm-to-Market Road 530 North and County Road 277. Sheriff Andy Louderback said an old cotton gin and seven bales of hay burned. A second small pasture fire was extinguished at Farm-to-Market 234 South about one mile south of U.S. 59. Causes of both fires are unknown.
In Goliad, Fire Chief Alonzo Morales, Jr. said 50 to 75 acres of pasture and brush on Abramite Road and Fannin Road caught fire about 12:15 p.m. An insulator on a power line cracked and sparked the ground on fire, he said.
Cuero Fire Chief Butch Tolbert said about eight acres of brush and grass caught fire about 1:30 p.m. near Verhelle Road and U.S. 87 South.
Fire officials Pray, Fox and Morales reminded the community to use severe caution and refrain from burning when necessary while conditions are uncertain.
"It was a large amount of fires for the day," Victoria Fire Department Battalion Chief Tracy Fox said. "The drought conditions are really what exasperated the fires today."
Firefighters responded to seven emergency fire calls in Victoria throughout the day: one house fire, five grass fires and a boat fire at Stratford Place Apartments. Fire departments around the Crossroads also responded to other grass fires.
A home in the 1900 block of Guadalupe Road was destroyed in a fire, first reported about 12:30 p.m.
Down the road about five miles, fire officials responded to a grass fire about 1 p.m., which sparked near U.S. 87 and Crouch and Menke roads. Fire Marshal Ron Pray said about 100-120 acres caught fire; the cause of the fire is unknown. The fire also damaged a railroad trestle, he said.
A second grass fire ignited on U.S. 87 and Sunray Road about 1:30 p.m., burning about 50 acres of brush. Strong winds downed an electrical wire, which caused the brush to catch fire, Pray said.
The two grass fires forced law enforcement officials to shut down U.S. 87 in both directions for about two hours.
On U.S. 77 and Farm-to-Market 445 and McFaddin Road, a third grass fire started about 2:30 p.m., burning about an acre of land. Fox said the cause is unknown.
A fourth grass fire ignited in the 1000 block of South Main Street about 4:30 p.m., burning about a half acre near a water pumping station. Fox said the cause is unknown.
A house located at 3465 Farm-to-Market Road 446 in Victoria, and about 10 acres of brush caught fire at 5:30 p.m. A resident of the home burning trash in the back yard was unable to contain the flames in the heavy winds. The fire spread to the rear of the home, burning one room and the attic.
A boat caught fire at Stratford Place Apartments, 3207 E. Airline Road. The fire was contained quickly, Pray said. The cause is still under investigation.
Outside the county, two fires occurred in Jackson County on Farm-to-Market Road 530 North and County Road 277. Sheriff Andy Louderback said an old cotton gin and seven bales of hay burned. A second small pasture fire was extinguished at Farm-to-Market 234 South about one mile south of U.S. 59. Causes of both fires are unknown.
In Goliad, Fire Chief Alonzo Morales, Jr. said 50 to 75 acres of pasture and brush on Abramite Road and Fannin Road caught fire about 12:15 p.m. An insulator on a power line cracked and sparked the ground on fire, he said.
Cuero Fire Chief Butch Tolbert said about eight acres of brush and grass caught fire about 1:30 p.m. near Verhelle Road and U.S. 87 South.
Fire officials Pray, Fox and Morales reminded the community to use severe caution and refrain from burning when necessary while conditions are uncertain.
2011年9月4日星期日
Energy saving starts at the top
Every square foot of the newly renovated Whittier Research Center is being used for research — even the roof.
In June, the junior-high-turned-research-facility became the first building at the University of Nebraska-Lincoln to be fitted with a state-of-the-art "green roof," made of small, drought-resistant, water-storing plants.
The 700-square-foot test plot provides an opportunity for researchers and landscapers to see how a green roof can be maintained, as well as test its purported benefits. Those benefits include increased stormwater retention, added insulation and preservation of the roof membrane.
The plants, called sedums, were grown by Roof Top Sedums LLC in Davenport, Iowa, and planted on the roof by UNL Landscape Services.
Emily Casper of UNL Landscape Services said the rooftop courtyard is easy to access and can be viewed from the top floors of the building.
"Before, it was just a white roof," she said. "Now the whole space is aesthetically pleasing."
The project adds a little more green to an already "green" building. Whittier was renovated along federal Leadership in Energy and Environmental Design (LEED) standards and uses geothermal energy.
Other Big Ten schools, such as Penn State University and Michigan State, have been experimenting with green-roof technology for years. In fact, Penn State's new $215 million Millennium Science Complex has six of them.
Green roofs also have been popping up off-campus in Nebraska. In Omaha, more than 10 green roofs have been installed on buildings within the past two to three years, said Kent Holm, the Douglas County environmental services director.
Holm explained that more and more businesses and building owners are looking for ways to save money and be energy-efficient.
Despite the startup cost of a green roof — the plants alone at Whittier were valued at nearly $10,000 — the benefit comes later through energy savings.
"With this type of technology, it's going to be more expensive initially. But the savings come in the long run because it extends the life of the roof membrane and serves as an insulator for the building," Holm said.
Casper said although the green roof at Whittier is still in its pilot stage, the research is important as more and more buildings look to meet efficiency standards.
"The U.S. ... is moving towards more sustainable green building practices, and green roofs are a natural part of that movement," she said.
In June, the junior-high-turned-research-facility became the first building at the University of Nebraska-Lincoln to be fitted with a state-of-the-art "green roof," made of small, drought-resistant, water-storing plants.
The 700-square-foot test plot provides an opportunity for researchers and landscapers to see how a green roof can be maintained, as well as test its purported benefits. Those benefits include increased stormwater retention, added insulation and preservation of the roof membrane.
The plants, called sedums, were grown by Roof Top Sedums LLC in Davenport, Iowa, and planted on the roof by UNL Landscape Services.
Emily Casper of UNL Landscape Services said the rooftop courtyard is easy to access and can be viewed from the top floors of the building.
"Before, it was just a white roof," she said. "Now the whole space is aesthetically pleasing."
The project adds a little more green to an already "green" building. Whittier was renovated along federal Leadership in Energy and Environmental Design (LEED) standards and uses geothermal energy.
Other Big Ten schools, such as Penn State University and Michigan State, have been experimenting with green-roof technology for years. In fact, Penn State's new $215 million Millennium Science Complex has six of them.
Green roofs also have been popping up off-campus in Nebraska. In Omaha, more than 10 green roofs have been installed on buildings within the past two to three years, said Kent Holm, the Douglas County environmental services director.
Holm explained that more and more businesses and building owners are looking for ways to save money and be energy-efficient.
Despite the startup cost of a green roof — the plants alone at Whittier were valued at nearly $10,000 — the benefit comes later through energy savings.
"With this type of technology, it's going to be more expensive initially. But the savings come in the long run because it extends the life of the roof membrane and serves as an insulator for the building," Holm said.
Casper said although the green roof at Whittier is still in its pilot stage, the research is important as more and more buildings look to meet efficiency standards.
"The U.S. ... is moving towards more sustainable green building practices, and green roofs are a natural part of that movement," she said.
2011年9月1日星期四
Fewer Hot Flashes Reported Among Older Heavier Women
In contradiction of recent evidence on menopausal women and hot flashes, a new study indicates that heavier women tend to have fewer hot flashes than those who are thinner. Interestingly, however, the trend is seen only among women aged 60 years and older.
Obesity has been regarded in recent years as a risk factor for hot flashes amid research indicating that heavier women tend to suffer from the menopause symptoms more commonly. These findings, which are based largely on epidemiologic studies, support a "thermoregulatory model," explain the researchers, "in which hot flashes represent heat dissipation events occurring in the context of the narrowed thermoneutral zone." Consistent with this theory is that body fat acts an insulator, increasing the frequency of hot flashes.
However, the new study, which was published online July 21 in the Journal of Clinical Endocrinology & Metabolism, suggests otherwise.
The researchers evaluated a subcohort of 52 women involved in the Study of Women's Health Across the Nation who reported hot flashes, still had their uterus and ovaries, and were not taking medications that would affect hot flashes.
Body fat, BMI, and waist circumference were most inversely associated with hot flashes among the oldest women in the sample.
Estradiol and sex hormone-binding globulin levels reduced, but did not eliminate, age-related variations in the association between body size and composition and hot flashes.
Black women reported more hot flashes; however, the association was not attributable to body size or composition: those associations were only apparent among white women, the authors wrote.
"This study provides a more nuanced understanding of the relationship between body size and hot flashes, emphasizing the important role of age," said the study's lead author, Rebecca Thurston, PhD, from the University of Pittsburgh, Pennsylvania in a press release.
"Our findings show that the benefit of higher fat levels for hot flashes is not apparent until a woman is about 60 years old."
Epidemiological studies published in the last decade or so indicate that women with higher BMIs and body fat levels are more likely to report hot flashes, but before those studies, body fat was traditionally regarded as being protective against hot flashes, and the so-called "thin hypothesis" prevailed.
Under this hypothesis, hot flashes occur because of hormonal changes including declining estrogen, and as androgens are aromatized into estrogens in body fat, women with greater levels of body fat should also have higher estrogen levels, and would logically have fewer hot flashes.
"Thinner women, lacking this extragonadal estrogen source, should have more hot flashes. [And t]his effect would be particularly relevant for older and postmenopausal women in whom extragonadal sources represent the primary source of estrogen," the researchers write.
Dr. Thurston said the new findings appear to back up that earlier theory.
"Our study showed that higher adiposity, BMI and waist circumference were associated with fewer physiologically-assessed hot flashes among older postmenopausal women with hot flashes," she noted in a press release.
"Moreover, associations were most pronounced among Caucasian women. This study underscores the importance of considering how age and race may modify the relationship between obesity and hot flashes."
Obesity has been regarded in recent years as a risk factor for hot flashes amid research indicating that heavier women tend to suffer from the menopause symptoms more commonly. These findings, which are based largely on epidemiologic studies, support a "thermoregulatory model," explain the researchers, "in which hot flashes represent heat dissipation events occurring in the context of the narrowed thermoneutral zone." Consistent with this theory is that body fat acts an insulator, increasing the frequency of hot flashes.
However, the new study, which was published online July 21 in the Journal of Clinical Endocrinology & Metabolism, suggests otherwise.
The researchers evaluated a subcohort of 52 women involved in the Study of Women's Health Across the Nation who reported hot flashes, still had their uterus and ovaries, and were not taking medications that would affect hot flashes.
Body fat, BMI, and waist circumference were most inversely associated with hot flashes among the oldest women in the sample.
Estradiol and sex hormone-binding globulin levels reduced, but did not eliminate, age-related variations in the association between body size and composition and hot flashes.
Black women reported more hot flashes; however, the association was not attributable to body size or composition: those associations were only apparent among white women, the authors wrote.
"This study provides a more nuanced understanding of the relationship between body size and hot flashes, emphasizing the important role of age," said the study's lead author, Rebecca Thurston, PhD, from the University of Pittsburgh, Pennsylvania in a press release.
"Our findings show that the benefit of higher fat levels for hot flashes is not apparent until a woman is about 60 years old."
Epidemiological studies published in the last decade or so indicate that women with higher BMIs and body fat levels are more likely to report hot flashes, but before those studies, body fat was traditionally regarded as being protective against hot flashes, and the so-called "thin hypothesis" prevailed.
Under this hypothesis, hot flashes occur because of hormonal changes including declining estrogen, and as androgens are aromatized into estrogens in body fat, women with greater levels of body fat should also have higher estrogen levels, and would logically have fewer hot flashes.
"Thinner women, lacking this extragonadal estrogen source, should have more hot flashes. [And t]his effect would be particularly relevant for older and postmenopausal women in whom extragonadal sources represent the primary source of estrogen," the researchers write.
Dr. Thurston said the new findings appear to back up that earlier theory.
"Our study showed that higher adiposity, BMI and waist circumference were associated with fewer physiologically-assessed hot flashes among older postmenopausal women with hot flashes," she noted in a press release.
"Moreover, associations were most pronounced among Caucasian women. This study underscores the importance of considering how age and race may modify the relationship between obesity and hot flashes."
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