Multi-scale Feature Extraction on Point-Sampled Surfaces

We present a new technique for extracting line‐type features on point‐sampled geometry. Given an unstructuredpoint cloud as input, our method first applies principal component analysis on local neighborhoods toclassify points according to the likelihood that they belong to a feature. Using hysteresis thresholding, we thencompute a minimum spanning graph as an initial approximation of the feature lines. To smooth out the featureswhile maintaining a close connection to the underlying surface, we use an adaptation of active contour models.Central to our method is a multi‐scale classification operator that allows feature analysis at multiplescales, using the size of the local neighborhoods as a discrete scale parameter. This significantly improves thereliability of the detection phase and makes our method more robust in the presence of noise. To illustrate theusefulness of our method, we have implemented a non‐photorealistic point renderer to visualize point‐sampledsurfaces as line drawings of their extracted feature curves.     

Pharmacologic approaches to chronic pain in the older adult

A key aspect of chronic pain management in the older adult is pharmacologic. Although not every elderly person has a chronic condition that leads to pain, these illnesses are more frequent in the later years as a consequence of the aging process. An understanding of physiologic changes and suggested pharmacologic interventions for dealing with issues related to chronic pain is essential. The psychosocial, cultural, and cost variables surrounding pain management of the older adult are also important to consider. A brief review of pain types and terminology precedes discussion of the key principles of pain management for the older adult. These principles are based on the guidelines published and distributed by the Agency for Health Care Policy and Research and the American Pain Society and are presented with a clinical focus aimed at improving clinician practice patterns related to pain management in the older adult. Concise, user-friendly medication information is presented to supplement the current knowledge base of practicing clinicians who prescribe analgesics and adjuvant medications for their patients with pain.     

Characterization of the passive film formed on weathering steels

Raman spectroscopy, infrared spectroscopy and electrochemical reduction techniques were used to characterize the passive film formed on weathering steels. Test pieces of weathering steel were exposed to an industrial environment for 4.5 and 8 yrs. In both cases the passive film was composed predominantly of 8-FeOOH with 10–20% γ-FeOOH and possibly some α-FeOOH. Raman spectra from different depths of the surface were identical which implied that the film composition was homogeneous.     

Interdiffusion between U-Zr fuelvs selected cladding steels

To better understand fuel-cladding compatibility issues as affected by diffusion processes in Argonne National Laboratory’s Integral Fast Reactors, interdiffusion studies were carried out with solid-solid diffusion couples assembled with a U-23 at. pct Zr alloy and cladding steels, such as 316, D9, and HT9. All diffusion couples were annealed at 700 °C and examined metallographically and by scanning electron microscopy-energy-dispersive spectroscopy analysis for diffusion structure development. The development of diffusion layers in the couples for various cladding steels is compared and discussed in light of the relative diffusion behavior of the individual elements, intermetallic formation, and experimental diffusion paths. In the context of fuel-cladding compatibility, HT9 is considered superior to 316 and D9, as it develops the smallest diffusion zone with the fewest number of phases. Formerly Graduate Student, School of Materials Engineering, Purdue University     

Methods of pattern recognition in the synthesis and identification of thin film optical systems

A layered medium is regarded as an input-output system in which the system structure is given by a parameter vector a. The output (e.g. reflectivity) is a computable function F(x,a) of the input x (e.g. wavelength, angle of incidence) and a. In synthesis a is to be determined such that F(x,a) is (in a certain sense) the best approximation of a prescribed behaviour; in the identification of the system the prescribed behaviour is replaced by a set of measurements. We consider a synthesis method based on a direct exploration of the frequency function F(x,a) without constructing a merit function. The parameter space is subjected to discretization. For each parameter vector a of this finite set we check the waveform y = F(x,a) for relevant phenomena. This method consumes a large amount of computation time and therefore requires efficient pattern recognition procedures; linguistic structure analysis is of special interest. We report algorithms for plateau detection, including numerical experiments.     

Heroin addiction and the Wechsler Digit Span test

There is some evidence that a Wechsler Digit Span scaled score well above the means of an individual's other WAIS subtest scores is diagnostically significant. Such positive Digit Span scatter seems to be a correlate of an interpersonal detachment syndrome characterized by superficial relationships and anhedonia. Negative scatter of Digit Span scaled scores considerably below the mean of other WAIS subtest scores have been viewed by some investigators as indicating depressive symptoms. Forty-two heroin addicts were compared with 41 neurotic depressive patients. The former group attained significantly higher average positive Digit Span scatter. Since heroin addicts appear more interpersonally distant and anhedonic for non-drug-related experiences, this finding was according to expectation. Digit Span scaled scores alone did not differentiate the groups. Digit Span scatter scores are clearly more desirable than scaled scores in the search for cognitive correlates of personality variables.     

Electron microscopy characterization of an as-fabricated research reactor fuel plate comprised of U–7Mo particles dispersed in an Al–2Si alloy matrix

To understand the microstructural development of nuclear fuel plates during irradiation, it is imperative to know the microstructure of a fuel plate after all the fabrication steps have been completed and before it is inserted into the reactor. To this end, a U–7 wt.% Mo alloy research reactor dispersion fuel plate with Al–2 wt.% Si matrix was destructively examined using scanning and transmission electron microscopy to characterize the developed microstructure after fabrication. Of particular interest for this study was how the Si that was added to the fuel matrix partitioned between the various fuel plate phases during fabrication. Si was added to the matrix so that the microstructure that developed during fuel fabrication would exhibit good irradiation behavior. SEM analysis was used to identify the representative microstructure, the compositions of the various phases, and the partitioning behavior of the fuel and matrix constituents. TEM analysis was employed to definitively identify the phases in the U–7Mo alloy and the phases that formed due to diffusional interactions between the fuel particles and matrix during fuel plate fabrication. The TEM results are the first reported for an as-fabricated U–7 wt.% Mo dispersion fuel plate with an Al alloy matrix. SEM results showed that a significant portion of the original γ-(U–Mo) fuel particles had transformed to a lamellar microstructure, comprised of α-U and either γ or γ' phases, and the fuel/matrix interaction layers were enriched in Si. TEM analysis identified an ordered fcc (U–Mo)(Al–Si)₃ type of phase, which formed at the decomposed U–7Mo/matrix interface and extended into the lamellar microstructure. Some regions of the U–7Mo particles retained the single-phase γ-(U–Mo). Small precipitate phases were observed in the fuel meat matrix that contained Fe, Al, and Si. The Si that is added to the matrix of a U–Mo dispersion fuel plate to improve irradiation performance appears to result in the creation of a Si-rich (U–Mo)(Al–Si)₃ type of fuel/matrix interaction layer during fabrication that appears to exhibit favorable behavior during irradiation compared to the behavior of the layers that form in U–Mo dispersion fuel plates without Si in the matrix.     

Strength properties of Scots pine from harbour piles degraded by erosion bacteria

140-year-old Scots pine piles displaying various levels of degradation by erosion bacteria were excavated from the harbour of Hamburg and investigated. Bending and compression strength correlated to the basic density, moisture content and lignin content. The compression strength was determined both on samples with dimensions of 30 mm?×?20 mm?×?20 mm and using 6.6 mm-increment cores taken perpendicular to the grain direction. Both sizes of the samples showed almost identical results. The sapwood of all samples was completely water-saturated; the heartwood did not even achieve 50% water saturation. The sapwood samples showed a good correlation between moisture content and strength properties, whereas basic density correlated well with the strength properties of both sapwood and heartwood. With increasing bacterial attack and resulting lower basic density, the lignin content increased in relation to holocellulose. The measured lignin content of the sapwood showed a good conformity with all strength properties. Determination of the lignin content represents an alternative method for predicting strength values of waterlogged wood while leaving most of the test material intact.     

Prevalence and toxigenicity of Clostridium difficile isolates in fecal microflora of preterm infants in the intensive care nursery

Fecal isolates of Clostridium difficile and its toxin B were followed prospectively in 50 preterm intensive care nursery (ICN) patients. The first stool specimen was obtained after 1 week of enteral feeding, at 15 +/- 1 days of life, and 2 more specimens were collected at 2-week intervals, 24 +/- 1 and 32 +/- 2 days of life. The stools were cultured for C. difficile, and tested for C. difficile toxin B. In the first specimen 15% of stools grew C. difficile. In the second specimen C. difficile isolation rates increased to 33% and plateaued. Toxin B was detected in 71, 93 and 100% of culture-positive stools in the first, second, and third specimens, respectively. C. difficile colonization was not associated with a higher incidence of necrotizing enterocolitis or diarrhea, and using precollected, frozen human milk did not protect from C. difficile colonization.