A validation of object-oriented design metrics as qualityindicators

This paper presents the results of a study in which we empirically investigated the suite of object-oriented (OO) design metrics introduced in (Chidamber and Kemerer, 1994). More specifically, our goal is to assess these metrics as predictors of fault-prone classes and, therefore, determine whether they can be used as early quality indicators. This study is complementary to the work described in (Li and Henry, 1993) where the same suite of metrics had been used to assess frequencies of maintenance changes to classes. To perform our validation accurately, we collected data on the development of eight medium-sized information management systems based on identical requirements. All eight projects were developed using a sequential life cycle model, a well-known OO analysis/design method and the C++ programming language. Based on empirical and quantitative analysis, the advantages and drawbacks of these OO metrics are discussed. Several of Chidamber and Kemerer's OO metrics appear to be useful to predict class fault-proneness during the early phases of the life-cycle. Also, on our data set, they are better predictors than “traditional” code metrics, which can only be collected at a later phase of the software development processes     

The evaluation of argon laser photocoagulation in a series of animal models of upper gastrointestinal bleeding

During the past five years we have evaluated argon laser photocoagulation in various canine models of upper gastrointestinal hemorrhage. In gastric erosions, the eight-watt argon laser was uniformly effective in stopping bleeding. In our standard acute ulcer model the seven-watt argon laser was effective in stopping bleeding from most ulcers and only occasionally produced deep injury. With the addition of a jet of CO2 exiting the laser catheter coaxial to the laser beam, the argon laser was 100% effective and no deep injury resulted. The application of the argon laser in a more physiologic canine bleeding model using a single bleeding vessel in an ulcer base is currently under study. The development of improved animal models of gastrointestinal bleeding should contribute to the identification of effective and safe endoscopic hemostatic methods.     

Foreign serum-induced pancreatitis in mice. II. Secretory disturbances of acinar cells

As previously reported, pancreatic acinar cell necrosis and inflammation develop in mice a few hours after one intraperitoneal injection of foreign serum. However, sublethally injured acinar cells exhibited notable increases in both zymogen granule numbers and amylase activity, observed within 3 hours and increasing with time. These two changes were coupled with a progressive decrease in the secretory response to pilocarpine and were preceded by significant disturbances in pancreatic tissue concentrations of sodium and potassium. We conclude that (1) the granule increase results from an induced disturbance of the granule exocytosis mechanism while granule formation continues and, therefore, (2) the granule secretory process is more sensitive to the serum injury mechanism than is the zymogen synthesis process. Although the granule increases developed in acinar cells throughout most of the nonnecrotic gland and persisted for at least 24 hours, acinar cell necrosis was maximal in extent--approximately 25% of the gland in severest form--by 12 to 15 hours. We conclude, therefore, that the increase in granules is neither the primary determinant nor initiator of acinar cell death. The latter is likely caused by disturbed plasma membrane functions, sufficient in some cells to result in lethal changes in ion and fluid composition. The injury mechanism, which permits granule formation to go on in the face of impaired granule exocytosis, is yet to be worked out. The possibilities are discussed in relationship to the reactivity of foreign sera for target cell plasma membranes.     

Patient-therapist matching for prediction of optimal and minimal therapeutic outcome

Exp I (a) established outcome criteria using evaluation ratings from 24 patient-therapist dyads; (b) produced 11 quantifiable personality predictors through factor analysis of 18 therapists' and 65 patients' scores on a test battery (including the MMPI and the Omnibus Personality Inventory); (c) identified 3 typological categories of both patients and therapists homogeneous with respect to these variables and 2 groups of therapists each homogeneous with respect to therapeutic approach; and (d) derived 5 regression equations predicting outcome for each patient and therapist group. Exp II, with 24 therapists and 56 patients who were university students or their spouses, utilized these findings to form 2 experimental dyad groups for which (a) optimal or (b) minimal therapist outcome ratings were predicted, and 2 control groups each for both optimal and deterioration matches that controlled for patient type and therapist type, respectively. Results indicate significant differences between mean outcome in the comparison of the deterioration-matched group both with its control and the optimally matched group. Findings demonstrate the usefulness of carefully planned matching techniques. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Secondary intraocular lens implantation

Mere aphakia is not an indication for secondary intraocular lens implantation. However, many patients with positive indications may be benefited most strikingly by this procedure. These indications are illustrated and results of the author's first 65 secondary implantations are analyzed.     

Partition of fish pheromones between water and aggregates of humic acids. Consequences for sexual signaling

High-molecular-weight suspended organic matter of soil and aquatic origins competes with water for the dissolution of relatively water insoluble organic substances. The same happens with microalgae and other organisms present in natural waters. Several pheromones, which play a specific role in the reproductive cycle of fish, are secreted to the water and are generally, if not always, molecules with hydrophobic or amphiphilic characteristics. The natural tendency of these pheromones to dissolve in suspended or deposited organic matter may cause their signaling function to be adversely affected. In this work we study the partition constants between water and organic reservoirs in suspension, Kh, of two fish pheromones, 4-pregnene-17 alpha, 20beta-diol-3-one (17,20beta-P) and prostaglandin F2alpha (PGF2alpha), and also of 4-pregnene-11beta,21-diol-3,20-dione 21-sulfate (21-P-sulfate), used as a proxy for sulfated steroid pheromones. Two types of organic reservoirs are employed: aggregates of suspended humic substances and negatively charged phospholipid vesicles. We find that the three compounds have high affinities for both types of aggregates. However, 17,20beta-P, with pKh = 4.4 +/- 0.2, is the only one for which we may predict a significant decrease in availability in consideration of the normal content of dissolved organic matter in natural waters. Also to be considered is the fact that a relatively large amount of pheromones is retained and may be released at an inopportune moment. How significant these phenomena are in nature is not as yet clear, considering the variety of habitats in which fish spawn and the little that is known about the nature and mode of action of pheromones.     

NORM workers: a challenge for internal dosimetry programmes

The mining, milling and processing of uranium and thorium bearing minerals may result in radiation doses to workers. The control of occupational exposures from these natural sources of radiation imposes a challenge to regulators and radiation protection advisers. A survey pilot programme, which included six mines in Brazil and a monazite plant, was established, consisting of the collection and analysis of concentrations of uranium, thorium and polonium in urine, faeces and air samples. Results from workers were compared to background data from their families living in the same area and from residents from the population of Rio de Janeiro. Positive exposure results were identified among the coal miners, the niobium miners and the monazite sand workers. Difficulties in the application of internal dosimetry programmes are discussed in relation to the control of NORM workers.     

Effect of different polypropylenes and compatibilizers on the rheological,mechanical and morphological properties of nylon 6/PP blends

In this work, the rheological, mechanical and morphological properties of nylon 6/polypropylene compatibilized blends were investigated. Two types of polypropylene were used. One with MFI of 40 g/10 min (PP H103) and the other with MFI of 3.5 g/10 min (PP H503). The compatibilizers used were polypropylene grafted with 6% of acrylic acid (PPgAA) and polypropylene grafted with 1% of maleic anhydride (PPgMA). The blends composition was 80/20 (wt%) for the PA6/PP binary blends and 80/10/10(wt%) for the nylon 6/PPgAA/polypropylene and nylon 6/PPgMA/polypropylene ternary blends. Torque rheometry analysis showed that when PPgAA and PPgMA were added to nylon 6/polypropylene blends, there was an increase in the torque, indicating that reactive compatibilization has occurred. There is no influence of the polypropylene MFI on the mechanical properties of the uncompatibilized and compatibilized blends. The impact strength of the blends containing PPgMA were greater than those of the blends containing PPgAA. The blends containing PPgAA are unstable. SEM analysis showed that PPgMA improves considerably the adhesion between PA6/PP phases, leading to good mechanical properties.