Events at Physics |
Events on Tuesday, September 29th, 2015
- Chaos & Complex Systems Seminar
- What’s a “bone attack” and why should I care?
- Time: 12:05 pm - 1:00 pm
- Place: 4274 Chamberlin (refreshments will be served)
- Speaker: Neil Binkley, UW Institute on Aging
- Abstract: We all know that heart attacks signify artery disease and that they may cause disability and even death. However, many people do not appreciate that fractures (broken bones) in older adults, what we are calling “bone attacks,” similarly indicate underlying bone and muscle disease. A Bone Attack is a broken bone (fracture) occurring in an adult age 50+ from a fall or other minimally traumatic event. Bone attacks are common and occur in 1:2 women and 1:4 men over 50. Fractures of the spine, hip and forearm are the most common types, but rib, pelvis and upper arm fractures also occur. Bone attacks, like heart attacks, are serious health events that may cause disability and even death. Indeed, 20-30% of older adults who break their hip die within one year and approximately half of those who survive a hip fracture require assistance with everyday activities and approximately 1/3 require nursing home care, some permanently.<br>
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Bone attacks (fractures) result from osteoporosis (bone loss) and sarcopenia (muscle loss) in older adults. In essence, both our bone and muscle strength decline as we age. This combination increases our risk for falling and when falls occur onto weakened bones, bone attacks (fractures) result. The likelihood of these fractures is increased by obesity and diabetes. Despite the high prevalence of these bone attacks, they remain largely ignored by physicians, patients and the healthcare system. It’s time for a change. - Host: Sprott
- Theory Seminar (High Energy/Cosmology)
- Cosmological Constraints on the Gravitational Interactions of Matter and Dark Matter
- Time: 3:00 pm - 4:00 pm
- Place: 5280 Chamberlin Hall
- Speaker: Ben Stefanek, University of Wisconsin-Madison
- Abstract: Although there is overwhelming evidence of dark matter from its gravitational interaction, we still do not know its precise gravitational interaction strength or whether it obeys the equivalence principle. Using the latest available cosmological data and working within the framework of LambdaCDM, we first update the measurement of the Newton's constant for all matter: $G_N=7.26^{+0.27}_{-0.27}times 10^{-11} m^3 kg^{-1} s^{-2}$, which differs by $2.2 sigma$ from the standard laboratory-based value. In general relativity, dark matter equivalence principle breaking can be mimicked by a long-range dark matter force mediated by an ultra light scalar field. Using the Planck three year data, we find that the dark matter "fifth-force" strength is constrained to be weaker than $10^{-4}$ of the gravitational force. We also introduce a phenomenological, post-Newtonian two-fluid description to explicitly break the equivalence principle by introducing a difference between dark matter inertial and gravitational masses. Depending on the decoupling time of the dark matter and ordinary matter fluids, the ratio of the dark matter gravitational mass to inertial mass is constrained to be unity at the $10^{-6}$ level.
- Host: Amol Upadhye
- Prospective Undergraduate Majors in Physics -- PUMP Meeting
- Time: 3:30 pm
- Place: 2103 Chamberlin Hall
- Speaker: Physics Department
- Abstract: Are you interested in physics?
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