Thermal behavior of quasiparticles in3He-B

We describe experiments on the transport of heat within a cell cooled by nuclear demagnetization of copper and containing³He-B at temperatures between 0.1 and 0.4 T_C. Within the bulk liquid helium, heat is transported by ballistic quasiparticles. In this case the conventional concept of boundary resistance is not applicable to the analysis of the heat exchange between refrigerant and³He. Rather, the cell geometry plays the important role. A thermal breakthrough in the cell is observed under conditions of heat flow large enough that the spin-lattice Korringa link to the copper refrigerant nuclei becomes saturated. At this point the lattice temperature rises, allowing heat to be transferred rapidly around the cell within the copper lattice, short-circuiting the liquid helium. We develop a simple model of heat transfer by ballistic quasiparticles which describes well the principal experimental features.     

Summary of the CALPHAD XXXVI 2007 conference

From 6–11 May 2007, 147 registered participants met at State College, Pennsylvania, for the thirty-sixth CALPHAD meeting organized by Zi-Kui Liu, Steve Hansen, Joanne Murray and Phillip Spencer. Activities were held at Toftrees Golf Resort and Conference Center with logistics run by graduate students and postdoctoral fellows from The Pennsylvania State University. Over the course of six days, 57 oral presentations and 84 posters were offered, the abstracts and titles of which are summarized in this report. Posters were on display from Sunday evening until Friday morning. In addition to the continuous display of the posters, two dedicated poster sessions were held in the Monday and Tuesday evenings, which were overwhelmingly enjoyed by the participants.

The CALPHAD Gibbs Triangle Award, an honor given only every three to five years, was bestowed upon Gunnar Eriksson. Fourteen CALPHAD scholarships were awarded to promising students in the field, the Best Paper Award for papers published in 2006 in the CALPHAD journal was conferred, and a Best Poster Award was chosen for one of the conference’s posters.     

Feedback-feedforward control of structures under seismic excitation

While the base acceleration resulting from a seismic activity on a civil engineering structure is not known a priori, it can be measured in real time. In this paper, it is shown that this extra information can be used for achieving a better control of the structure with little additional effort. The approach taken is to augment the equations of motion for the structural system with an appropriate model of the earthquake excitation based on filtering a Gaussian white noise process. The augmented equations of motion are used to determine a control which utilizes both feedback and feedforward compensation. The feedback loop incorporates measurements of the response of the structure into the control law. The information from both the structure and the earthquake excitation model is utilized in the feedforward control law with an observer designed to estimate the states of the eartquake model based upon the base acceleration measurements. A quadratic performance index is used as a measure of optimality of the control algorithms. Results are given which indicate that the proposed method offers advantages in performance over the control method employing only state feedback and that it is also able to improve upon results of the recently develped instntaneous control algorithms. It is also shown that the nostationarity in the earthquake excitation can often be neglected in practical design of linear systems. Finally, a discussion is given of how the method might be coupled with equivalent linearization techniques and extended for use with nonlinear structures.     

Endoscopic CO2 laser excision of large or recurrent laryngeal saccular cysts in adults

BACKGROUND: Most paediatric cardiac arrest studies have been conducted in the USA, where paramedics provide prehospital emergency care. We wanted to study the outcome of paediatric cardiac arrest patients in an emergency medical system which is based on physician staffed emergency care units. METHODS: We analysed retrospectively the files of 100 prehospital cardiac arrest patients from Southern Finland during a 10-year study period. The patients were less than 16 years of age. RESULTS: Fifty patients were declared dead on the scene (DOS) without attempted resuscitation, and cardiopulmonary resuscitation (CPR) was initiated in 50 patients. The sudden infant death syndrome was the most common cause of arrest in the DOS patients (68%) as well as in those receiving CPR (36%). Asystole was the initial cardiac rhythm in 70% of the patients in whom CPR was attempted. Resuscitation was successful in 13 patients, 8 of whom were ultimately discharged. Six of the patients survived with mild or no disability and 4 of them had near-drowning aetiology. In multivariate analysis, the short duration of CPR (< or = 15 min) was the only factor significantly associated with better survival. CONCLUSIONS: Although prehospital care was provided by physicians, the overall rate of survival was found to be equally poor as reported from systems with paramedics. The only major difference between physician- and paramedic-staffed emergency care units is the ability of physicians to refrain from resuscitation already on the scene when prognosis is poor.     

Follicular vascularity--the predictive value of transvaginal power Doppler ultrasonography in an in-vitro fertilization programme: a preliminary study

The glnA gene from the human pathogen Streptococcus agalactiae was cloned from a genomic library prepared with the lambda phage vector lambdaDASHII. A 4.6-kb DNA fragment of one of the recombinant phages was subcloned in pUC18. This Escherichia coli clone expressed a 52-kDa protein encoded by a 1,341-bp open reading frame. The nucleotide sequence of the open reading frame and the deduced amino acid sequence shared a significant degree of homology with the sequences of other glutamine synthetases (GS). The highest homology was between our deduced protein and GS of gram-positive bacteria such as Bacillus subtilis, Bacillus cereus, and Staphylococcus aureus. Plasmids with the cloned streptococcal glnA were able to complement E. coli glnA mutants grown on minimal media. Rabbit antisera to streptococcal GS recombinant protein recognized not only the recombinant protein but also a similar-sized band in mutanolysin extracts of all group B streptococcal strains tested, regardless of polysaccharide type or surface protein profile. The amino acid sequence of the deduced protein had similarities to other streptococcal cell-surface-bound proteins. The possible functional role of the immunological features of streptococcal GS is discussed.     

Multifactorial analysis of lung cancer dose-response relationships for workers at the Mayak nuclear enterprise

Dose-response relationships for alpha-radiation-induced lung cancers (adenocarcinoma, squamous carcinoma and small cell carcinoma) were developed by multifactorial analysis using data for Mayak nuclear enterprise workers chronically exposed by inhalation to 239Pu. The three most important lung cancer risk factors (smoking, plutonium incorporation, and external gamma irradiation), out of six factors previously identified, were used. Relative risks (odds ratios) were determined for 500 nuclear enterprise workers (162 cancer cases, 338 control) for different dose levels using a case-control study design and logistic regression. A threshold at about 3.7 kBq or 0.80 Gy was discovered for incorporated plutonium, which is satisfactorily described by linear-quadratic and quadratic models. Excess relative risk was 0.020 kBq(-2) and 0.97 Gy(-2). This quadratic function was mainly due to adenocarcinoma. A trend for decreasing risk was noted for the lowest levels of plutonium incorporation, near permissible level. No clear-cut dose-response relationship for lung cancer induction by chronic external gamma irradiation was obtained. Lung cancer induction by cigarette smoking had a linear dependence: smoking of one pack of papiroses (a type of Russian cigarette) per day for 5 y increases the lung cancer risk twofold. The effect was most clearly manifested for squamous-cell carcinoma.