Effect of heat treatment on mechanical dissipation in Ta2_2O5_5 coatings

Thermal noise arising from mechanical dissipation in dielectric reflective coatings is expected to critically limit the sensitivity of precision measurement systems such as high-resolution optical spectroscopy, optical frequency standards and future generations of interferometric gravitational wave detectors. We present measurements of the effect of post-deposition heat treatment on the temperature dependence of the mechanical dissipation in ion-beam sputtered tantalum pentoxide between 11\,K and 300\,K. We find the temperature dependence of the dissipation is strongly dependent on the temperature at which the heat treatment was carried out, and we have identified three dissipation peaks occurring at different heat treatment temperatures. At temperatures below 200\,K, the magnitude of the loss was found to increase with higher heat treatment temperatures, indicating that heat treatment is a significant factor in determining the level of coating thermal noise.Comment: accepted Classical and Quantum Gravity 201

Measurements of a low temperature mechanical dissipation peak in a single layer of Ta2O5 doped with TiO2

Thermal noise arising from mechanical dissipation in oxide coatings is a major limitation to many precision measurement systems, including optical frequency standards, high resolution optical spectroscopy and interferometric gravity wave detectors. Presented here are measurements of dissipation as a function of temperature between 7 K and 290 K in ion-beam sputtered Ta2O5 doped with TiO2, showing a loss peak at 20 K. Analysis of the peak provides the first evidence of the source of dissipation in doped Ta2O5 coatings, leading to possibilities for the reduction of thermal noise effects

Hole dynamics in noble metals

We present a detailed analysis of hole dynamics in noble metals (Cu and Au), by means of first-principles many-body calculations. While holes in a free-electron gas are known to live shorter than electrons with the same excitation energy, our results indicate that d-holes in noble metals exhibit longer inelastic lifetimes than excited sp-electrons, in agreement with experiment. The density of states available for d-hole decay is larger than that for the decay of excited electrons; however, the small overlap between d- and sp-states below the Fermi level increases the d-hole lifetime. The impact of d-hole dynamics on electron-hole correlation effects, which are of relevance in the analysis of time-resolved two-photon photoemission experiments, is also addressed.Comment: 4 pages, 2 figures, to appear in Phys. Rev. Let

Renal homotransplantation in pediatric patients.

Fifty-seven patients were treated with renal homotransplantation from 1½ to 7⅔ years ago; 23 patients were 12 years or younger and the other 34 patients were 13 to 18. Family members (usually parents) were the primary donors in 45 cases. Unrelated volunteers or cadavers donated the other 12 homografts. Immunosuppression was with azathioprine and prednisone, and in some cases also with ALG. Forty-two of the 57 recipients survived for at least 1 year. Additional deaths occurred at 17½ and 19 months leaving 40 recipients (70.2%) alive. Six survivors had successful retransplantation following late failure of their original homografts. Control of rejection was not particularly different than in adult cases. “Homograft glomerulonephritis” was found in chronically tolerated transplants, but no more frequently than in older patients. Many postoperative problems in the pediatric age group were the consequence of retardation of growth caused either by pre-existing uremia or by the need for high dose postoperative steroid therapy, orthopedic accidents such as femoral and vertebral fractures, and psychiatric complications which led to two suicides. In spite of these difficulties, the meaningful rehabilitation that was obtained in the chronic survivors makes us regard pediatric patients as favorable candidates for therapy with renal transplantation

Carbon reductions and health co-benefits from US residential energy efficiency measures

The United States (US) Clean Power Plan established state-specific carbon dioxide (CO2) emissions reduction goals for fossil fuel-fired electricity generating units (EGUs). States may achieve these goals through multiple mechanisms, including measures that can achieve equivalent CO2 reductions such as residential energy efficiency, which will have important co-benefits. Here, we develop state-resolution simulations of the economic, health, and climate benefits of increased residential insulation, considering EGUs and residential combustion. Increasing insulation to International Energy Conservation Code 2012 levels for all single-family homes in the US in 2013 would lead to annual reductions of 80 million tons of CO2 from EGUs, with annual co-benefits including 30 million tons of CO2 from residential combustion and 320 premature deaths associated with criteria pollutant emissions from both EGUs and residential combustion sources. Monetized climate and health co-benefits average $49 per ton of CO2 reduced from EGUs (range across states:$12–$390). State-specific co-benefit estimates can inform development of optimal Clean Power Plan implementation strategies

Clinicopathological features of extranodal lymphomas: Kuwait experience

A total of 935 patients with extranodal non-Hodgkin lymphoma (NHL) diagnosed in the period between January 1985 and December 2000 in Kuwait Cancer Center, serving the whole population of Kuwait, were used to describe the clinicopathological and epidemiological features of extranodal lymphomas in Kuwait. Extranodal lymphomas accounted for 45% of all NHL observed during this time. All NHL cases from Kuwait Cancer registry were analyzed and pathologically reclassified using the latest WHO ( 2000) classification. The most common lymphoma observed was diffuse large B-cell lymphoma (58.60%) followed by Burkitt's lymphoma (BL) (3.80%). In the pediatric group, BL comprises more than two thirds of all patients (77.20%). The most common extranodal sites were stomach (19.70%) and skin (17.80%) in the adult group, large intestine (29.80%) and small intestine (19.30%) in the pediatric age group. The majority (73.40%) of adult extranodal lymphomas was in stage IE - IIE and had a very good prognosis. On the contrary, the majority of pediatric extranodal lymphomas were found to be in stage III and IV. Variations in treatment policies ( single agent or combined chemotherapy, radiotherapy, combined modality treatment) adopted and changed during the time period of 16 years of this retrospective study were documented. Copyright (C) 2004 S. Karger AG, Basel