An experiment to detect gravity at sub-mm scale with high-Q mechanical oscillators

Silicon double paddle oscillators are well suited for the detection of weak forces because of their high Q factor (about 10^5 at room temperature). We describe an experiment aimed at the detection of gravitational forces between masses at sub-mm distance using such an oscillator. Gravitational excitation is produced by a rotating aluminium disk with platinum segments. The force sensitivity of this apparatus is about 10 fN at room temperature for 1000 s averaging time at room temperature. The current limitations to detection of the gravitational force are mentioned.Comment: 19 pages, to appear in Proceedings of the Tenth Marcel Grossmann Meeting on General Relativity, edited by M. Novello, S. Perez-Bergliaffa and R. Ruffini, World Scientific. Revision: portable format and revised figure

An experiment to detect gravity at sub-mm scale with high Q mechanical oscillators,” presented at the Tenth Marcel Grossmann Meeting on General Relativity, Rio de Janeiro

Silicon double paddle oscillators are well suited for the detection of weak forces because of their high Q factor (about 10 5 at room temperature). We describe an experiment aimed at the detection of gravitational forces between masses at sub-mm distance using such an oscillator. Gravitational excitation is produced by a rotating aluminium disk with platinum segments. The force sensitivity of this apparatus is about 10 fN at room temperature for 1000 s averaging time at room temperature. The current limitations to detection of the gravitational force are mentioned

Caudal analgesia in children: S(+)-ketamine vs S(+)-ketamine plus clonidine

Background: The aim of this study was to evaluate postoperative analgesia provided by caudal S(+)-ketamine and S(+)-ketamine plus clonidine without local anesthetic. Methods: Forty-four children aged 1-5 years consecutively scheduled for inguinal hernia repair, hydrocele repair or orchidopexy were randomly assigned to receive a caudal injection of either S(+)-ketamine 1 mg.kg(-1) (group K) or S(+)-ketamine 0.5 mg.kg(-1) plus clonidine 1 mug.kg(-1) (group KC). Postoperative analgesia and sedation were evaluated by CHEOPS and Ramsay scale from emergence from general anesthesia for 24 h. Results: No statistical difference was observed between study groups with respect to pain and sedation assessment. A slight trend toward a reduced requirement for rescue analgesia in group KC was observed, although not statistically significant. Conclusions: Caudal S(+)-ketamine 1 mg.kg(-1) and S(+)-ketamine 0.5 mg.kg(-1) plus clonidine 1 mug.kg(-1) are safe and provide effective postoperative analgesia in children without adverse effects