The Coldest Place in the Universe: Probing the Ultra-Cold Outflow and Dusty Disk in the Boomerang Nebula

Our Cycle 0 ALMA observations confirmed that the Boomerang Nebula is the coldest known object in the Universe, with a massive high-speed outflow that has cooled significantly below the cosmic background temperature. Our new CO 1-0 data reveal heretofore unseen distant regions of this ultra-cold outflow, out to $\gtrsim120,000$ AU. We find that in the ultra-cold outflow, the mass-loss rate (dM/dt) increases with radius, similar to its expansion velocity ($V$) - taking $V\propto r$, we find $dM/dt \propto r^{0.9-2.2}$. The mass in the ultra-cold outflow is $\gtrsim3.3$ Msun, and the Boomerang's main-sequence progenitor mass is $\gtrsim4$ Msun. Our high angular resolution ($\sim$0".3) CO J=3-2 map shows the inner bipolar nebula's precise, highly-collimated shape, and a dense central waist of size (FWHM) $\sim$1740 AU$\times275$ AU. The molecular gas and the dust as seen in scattered light via optical HST imaging show a detailed correspondence. The waist shows a compact core in thermal dust emission at 0.87-3.3 mm, which harbors $(4-7)\times10^{-4}$ Msun~of very large ($\sim$mm-to-cm sized), cold ($\sim20-30$ K) grains. The central waist (assuming its outer regions to be expanding) and fast bipolar outflow have expansion ages of $\lesssim1925$ yr and $\le1050$ yr: the "jet-lag" (i.e., torus age minus the fast-outflow age) in the Boomerang supports models in which the primary star interacts directly with a binary companion. We argue that this interaction resulted in a common-envelope configuration while the Boomerang's primary was an RGB or early-AGB star, with the companion finally merging into the primary's core, and ejecting the primary's envelope that now forms the ultra-cold outflow.Comment: accepted ApJ, 12 Apr, 201

Use of personal call alarms among community-dwelling older people.

Having a fall and then lying on the floor for an hour or more is known as a ‘long lie’, which are associated with serious injury and an elevated risk of admission to hospital, long-term care, and death. Personal call alarms are designed to prevent long lies, although little is known about their use. Using cross-sectional data from the English Longitudinal Study on Ageing, this study investigated the proportion of self-reported users of personal call alarms among 3091 community-dwelling adults aged 65+ who reported difficulties of mobility or activities of daily living. The characteristics of users were then explored through logistic regressions comparing those living alone with those living with others. One hundred and eighty people self-reported using a personal call alarm (6%). Multivariate regression found the following to significantly predict personal call alarm use among both those living alone and with others: greater difficulty with activities / instrumental activities of daily living, older age, and for those living with others only: lower score on the quality of life subscale for control. Personal call alarm use may be markedly lower than the 30 per cent annual incidence of falls among community-dwelling older people. Better understanding is needed of the reasons for low usage, even amongst those at highest falls risk for whom such alarms are most likely to be beneficial

The Off-Shell Nucleon-Nucleon Amplitude: Why it is Unmeasurable in Nucleon-Nucleon Bremsstrahlung

Nucleon-nucleon bremsstrahlung has long been considered a way of getting information about the off-shell nucleon-nucleon amplitude which would allow one to distinguish among nucleon-nucleon potentials based on their off-shell properties. There have been many calculations and many experiments devoted to this aim. We show here, in contrast to this standard view, that such off-shell amplitudes are not measurable as a matter of principle. This follows formally from the invariance of the S-matrix under transformations of the fields. This result is discussed here and illustrated via two simple models, one applying to spin zero, and one to spin one half, processes. The latter model is very closely related to phenomenological models which have been used to study off-shell effects at electromagnetic vertices.Comment: 6 pages, Latex, uses FBSsuppl.cls - Invited plenary talk at the Asia Pacific Conference on Few Body Problems in Physics, Noda/Kashiwa, Japan, August, 1999 - To be published in Few Body Systems Supp

High magnetic field superconducting properties of Nb3Sn films Final report

High magnetic field superconducting properties of niobium stannide films and shielding characterictics of stannide layer

Electromagnetic Polarizabilities and Charge Radii of the Nucleons in the Diquark-model

The diquark model is used to calculate the electromagnetic polarizabilities and charge radii of the nucleons for three different potentials. Making the scalar diquark lower in mass introduces a mixing angle $\theta$ between the $\left| 56\right\rangle$ and $\left| 70\right\rangle$ states ,which allows an improvement in value of all 6 properties. Generalizing the Gamov-Teller matrix and the magnetic moment operator to the diquark model gives constraints on this mixing. We obtain for the Richardson potential $\theta =23.2^{\circ },$ $\overline{\alpha }_p=7.9_{-0.9}^{+1.0}\times 10^{-4}fm^3,$ $\overline{\alpha }_n=7.7_{-0.6}^{+0.3}\times 10^{-4}fm^3,$ $\overline{\beta }_p=5.4_{-0.4}^{+1.6}\times 10^{-4}fm^3,$ $\overline{\beta }_n=6.7_{-0.7}^{+1.3}\times 10^{-4}fm^3,$ $\left\langle r^2\right\rangle _p=0.37_{-0.03}^{+0.02}fm^2,$ $\left\langle r^2\right\rangle _n=-0.07_{-0.02}^{+0.03}fm^2.$ Additional pion cloud contributions could improve on all six results.Comment: 15 Pages, Latex, Figs on request, to be published Phys.Lett.B. Minor errors corrected and eqn 5,6,8,9 correcte