The influence of projectile charge state on ionization probabilities of sputtered atoms

The ionization probability of atoms sputtered from a clean polycrystalline metal surface was measured for different charge states of the projectile used to bombard the sample. More specifically, a polycrystalline indium surface was irradiated with Ar⁺ and Ar⁰ beams of energies between 5 and 15 keV, and In⁺ secondary ions and neutral In atoms emitted from the surface were detected under identical experimental conditions regarding the sampled emission angle and energy. The resulting energy integrated ionization probability of sputtered In atoms is consistently found to be smaller for neutral projectiles, the difference decreasing with decreasing impact energy. The observed trends agree with those measured for kinetic electron emission, indicating that secondary ion formation is at least partly governed by kinetic substrate excitation.     

Determination of deuterium in dead-sea water by nuclear methods

By using the D(d, p)³H nuclear reaction combined with the Rutherford-backscattering method, the amount of D₂O in relation to H₂O in water from the Dead Sea is measured. The amount of deuterium in the samples is determined from the integrated yield of the D(d, p)³H reaction in relation to the ¹⁶O(d, p₀)¹⁷O or ¹⁶O(d, p₁)¹⁷O reaction. For the low deuteron energies used (E 0.63 MeV), the differential cross section of the ¹⁶O(d, p₀)¹⁷O reaction was determined experimentally. No significant change of deuterium concentration in Dead-Sea water down to a depth of 36 m could be detected.     

Early office-based vs late hospital-based nasolacrimal duct probing. A clinical decision analysis

BACKGROUND: Controversy exists regarding the treatment of infants with symptomatic nasolacrimal duct obstruction. One philosophy advocates "early" nasolacrimal duct probing, generally in the office. An alternate strategy advocates medical management until the infant is approximately 12 months old to allow for spontaneous resolution, with those with persistent nasolacrimal duct obstruction usually treated by "late" probing in the hospital with the use of general anesthesia. METHODS: We used clinical decision analysis to compare these two opposing treatment strategies. A decision tree was constructed with the usual designations for probability nodes and decision points, comparing early probing at 6 months of age in the office and late probing at 12 months of age in the hospital. The initial decision point thus addressed treatment of children who still had symptomatic nasolacrimal duct obstruction at 6 months of age. One repeated probing under same-strategy conditions was performed for patients in whom initial office probing failed. Values for probability nodes were derived from the ophthalmic literature, including a 70% rate of spontaneous resolution of nasolacrimal duct obstruction between the ages of 6 and 12 months. RESULTS: Both the early office probing strategy and the late hospital probing strategy yielded success rates greater than 99%. Based on prevailing fees, the late hospital strategy cost $2,310,000 more than the early office strategy per 10,000 patients, even though fewer procedures were performed. CONCLUSION: Early office probing and late hospital probing have similar high success rates, albeit at a higher cost for the late hospital probing strategy.     

The refinement of retinotectal projection on tectal whole mount during the regeneration of the goldfish optic nerve labeled with DiI anterogradely

Radiographic computed tomography and magnetic resonance imaging are the procedures of choice in the diagnosis of patients with suspected pituitary gland abnormalities. Several cases are presented where the diagnostic value of such procedures in patients with diseases affecting the pituitary gland is demonstrated.     

Digital multi-filter auditory prosthesis: study of its efficiency in function of number of filters and their programming

A new method to determine a rate constant and total reaction product using data of reaction product kinetics is proposed. The method is based on the solution of the system of irrational equations (for special case), which describes such processes. This method was used to determine the reaction rate constant of interaction of some monoclonal antibodies with the antigens immobilized on immunological plates.     

A signal-detection theory based perspective on design of warning

The effects of warnings are analyzed using a distributed signal-detection theory model. It is established that selectivity always increases effectiveness. The implications to optimal warning design for intermittent versus continuous hazards are discussed. The changes in the behavior of the 6 human subjects in response to changes in the warning levels are consistent with the predictions of the model.     

Open-heart correction of tetralogy of Fallot in an acyanotic dog

Tetralogy of Fallot was diagnosed in an acyanotic 11-month-old dog. Predicted pressure gradient across the pulmonic valve, as assessed by use of continuous wave Doppler echocardiography, was 94.5 mm Hg. Bidirectional shunting was identified by means of selective angiography. Open-heart correction was performed, using a transatrial approach with limited ventriculotomy and cardiopulmonary bypass. The hypertrophied infundibulum was resected, the ventricular septal defect was closed primarily, and a transannular pericardial patch graft was applied. Pressure gradients across the pulmonic valve were 52.9 and 22.8 mm Hg 2 weeks and 4 months after surgery, respectively. Advances in cardiopulmonary bypass, anesthetic management, and use of the transatrial approach may improve the success of open-heart correction of tetralogy of Fallot in dogs.