Fred: An approach to generating real, correct, reusable programs from proofs

In this paper we describe our system for automatically extracting "correct" programs from proofs using a development of the Curry-Howard process. Although program extraction has been developed by many authors, our system has a number of novel features designed to make it very easy to use and as close as possible to ordinary mathematical terminology and practice. These features include 1. the use of Henkin's technique to reduce higher-order logic to many-sorted (first-order) logic; 2. the free use of new rules for induction subject to certain conditions; 3. the extensive use of previously programmed (total, recursive) functions; 4. the use of templates to make the reasoning much closer to normal mathematical proofs and 5. a conceptual distinction between the computational type theory (for representing programs)and the logical type theory (for reasoning about programs). As an example of our system we give a constructive proof of the well known theorem that every graph of even parity, which is non-trivial in the sense that it does not consist of isolated vertices, has a cycle. Given such a graph as input, the extracted program produces a cycle as promised.

Using Just-in-Time Data to Intervene with At-Risk Students

With increasing state and federal policy pressure to increase retention and graduation rates, academic affairs leaders seek metrics to track that predict student success. This report analyzes behavioral, academic, and financial indicators of student risk and suggests actions administrators can take to intervene with students who cross risk thresholds.

Using Just in Time Data to Intervene with At-Risk Students

With increasing state and federal policy pressure to increase retention and graduation rates, academic affairs leaders seek metrics to track that predict student success. This report analyzes behavioral, academic, and financial indicators of student risk and suggests actions administrators can take to intervene with students who cross risk thresholds.

A morte do filho: observação psicológica de famílias de crianças leucêmicas

Esse trabalho é um estudo descritivo de campo com fins exploratórios que permitam situar a problemática da perda do filho, em famílias de crianças leucêmicas, com o objetivo de explicitar um atendimento psicológico para apoiar essas famílias. Nesse intuito, procurou-se observar os padrões de comportamento encontrados nessas famílias desde o aparecimento da doença, as mudanças que surgiram devido à ameaça de morte e o falecimento. Estudos feitos por médicos, enfermeiras, psiquiatras assistentes sociais e psicólogos que trabalham com doentes graves e pacientes terminais, forneceram parâmentros para nortearem o que foi observado em campo. O estudo foi realizado no IPPMG, hospital-escola pertencente à UFRJ. Observou-se a situação de quatorze famílias de crianças leucêmicas no decorrer da doença através de entrevistas individuais não diretivas e observações no contexto da Instituição. Baseando-se em padrões de comportamento que foram encontrados por vários autores em trabalhos com pacientes terminais e também observados nesse estudo, levantou-se a hipótese que a partir desses padrões de comportamento é possível desenvolver meios de acompanhamento psicológico para ajudar essas famílias a viverem esse período de crise - a perda do filho. Foi constatado que a própria equipe de saúde também está vivendo essa crise e passa pelos mesmos padrões de comportamento que a família. Assim sendo, seria necessário ulteriormente prever um trabalho com a equipe de saúde para que essa possa lidar mais com as famílias e com o impacto da morte.

In vitro and in situ activity of carboxymethyl cellulase and glutamate dehydrogenase according to supplementation with different nitrogenous compounds

Two experiments were carried out to evaluate the effect of supplementation with different nitrogenous compounds on the activities of carboxymethil cellulase (CMCase) and glutamate dehydrogenase (GDH). In the first experiment, four treatments were evaluated in vitro: cellulose, cellulose with casein, cellulose with urea, and cellulose with casamino acids. After 6, 12 and 24 hours of incubation, CMCase and GDH activity, pH, and concentrations of ammonia nitrogen (AN) and microbial protein were measured. In the three incubation periods, the concentration of AN was higher when urea was used as a supplemental source of nitrogen. The activity of CMCase was higher with the addition of urea and casamino acids when compared with the control and the casein treatment. Supplementation with casamino acids provided higher GDH activity when compared with the control at 6 hours of incubation. At 12 hours of incubation, the GHD activity was also stimulated by casein. At 24 hours, there was no difference in GHD activity among treatments. In the second experiment, three rumen-fistulated bulls were used for in situ evaluation. Animals were fed Tifton hay (Cynodon sp.) ad libitum. The treatments consisted of control (no supplementation), supplementation with non-protein nitrogenous compounds (urea and ammonium sulphate, 9:1) and supplementation with protein (albumin). In treatments with nitrogenous compound supplementation, 1 g of crude protein/kg of body weight was supplied. The experiment was conducted in a 3 × 3 Latin square design. The measurements were performed at 6, 12 and 24 hours after supplementation. No difference in GDH activity was observed among treatments. The control treatment showed higher CMCase activity when compared with the treatments containing supplemental sources of nitrogen. However, urea supplementation provided higher CMCase activity compared to albumin.

Evaluation of renal and hepatic functions in dogs naturally infected by visceral leishmaniasis submitted to treatment with meglumine antimoniate

The present study aimed to evaluate the renal and hepatic responses in eight dogs with visceral leishmaniasis submitted to treatment with meglumine antimoniate and to verify the occurrence of possible side effects. Urinalysis, hepatic and renal function tests were carried out in all animals at up to seven moments. After the end of a six-month observation period, all dogs were euthanized. Before the beginning of the experiment urinary and biochemical alterations were observed in four dogs due to the changes caused by the parasite itself. These alterations included the presence of renal cells, cylindruria, proteinuria, azotemia, hyperproteinemia, and hypoalbuminemia. One dog died on the third day after treatment because an aggravation of the clinical picture, probably due to the medication. During the course of the study, an increase in hepatic enzymes was verified in two animals. Sixty days after the beginning of the treatment four dogs showed remission of clinical signs. The other three were asymptomatic with persistent biochemical alterations. From these, two presented recurrence of clinical signs about 150 days after the beginning of the treatment while in the other, hyperproteinemia persisted. Meglumine antimoniate was not efficient to treat dogs with severe renal dysfunction and the side effects observed were pain at the site of injection and the probable transient hepatotoxicity, evidenced by biochemical examinations, but without the presence of clinical signs. (c) 2006 Elsevier Ltd. All rights reserved.

Clinical and parasitological evaluation of dogs naturally infected by Leishmania (Leishmania) chagasi submitted to treatment with meglumine antimoniate

Aiming to evaluate the efficacy of the treatment of canine visceral leishmaniasis, to verify the occurrence of a possible disease relapse, and to search for the presence of the parasites after the end of the treatment, seven dogs naturally infected by Leishmania (Leishmania) chagasi were used. The dogs were subjected to a treatment with 75 mg/kg meglumine antimoniate subcutaneously every 12 h for 21 days, and followed-up for a period of 6 months. During the whole experimental period the animals wore deltamethrin collars and were kept in a screened kennel to avoid reinfection. Lymph node and bone marrow aspiration biopsy was carried out to search for the parasite at seven moments: before the treatment, 30, 60, 90, 120 150 and 180 days after the start of the treatment. After the end of the experiment all dogs were humanely euthanized. Then, spleen and liver imprints and ill vitro cultures were carried out to search for amastigote forms of the parasite. During the treatment all animals presented remission of symptoms. However, two dogs were observed to present new symptoms in the course of the experiment. At the end of the experiment, the presence of amastigote forms of the parasite was evidenced in five of the seven dogs. This enabled us to conclude that the treatment promoted clinical cure but did not eliminate the parasites completely. (c) 2006 Elsevier B.V. All rights reserved.

The Q-D algorithm for transforming series expansions into a corresponding continued fraction: an extension to cope with zero coefficients

An algorithm for deriving a continued fraction that corresponds to two series expansions simultaneously, when there are zero coefficients in one or both series, is given. It is based on using the Q-D algorithm to derive the corresponding fraction for two related series, and then transforming it into the required continued fraction. Two examples are given. (C) 2003 Elsevier B.V. All rights reserved.

Effect of Static and Cyclic Loading on Ceramic Laminate Veneers Adhered to Teeth with and Without Aged Composite Restorations

Purpose: Existing composite restorations on teeth are often remade prior to the cementation of fixed dental prostheses. The aim of this study was to evaluate the effect of static and cyclic loading on ceramic laminate veneers adhered to aged resin composite restorations.Materials and Methods: Eighty sound maxillary incisors were collected and randomly divided into four groups: group 1: control group, no restorations; group 2: two Class III restorations; group 3: two Class IV restorations; group 4: complete composite substrate. Standard composite restorations were made using a microhybrid resin composite (Anterior Shine). Restored teeth were subjected to thermocycling (6000 cycles). Window preparations were made on the labial surface of the teeth for ceramic laminate fabrication (Empress II). Teeth were conditioned using an etch-and-rinse system. Existing composite restorations representing the aged composites were silica coated (CoJet) and silanized (ESPE-Sil). Ceramic laminates were cemented using a bis-GMA-based cement (Variolink Veneer). The specimens were randomly divided into two groups and were subjected to either static (groups 1a, 2a, 3a, 4a) or cyclic loading (groups 1b, 2b, 3b, 4b). Failure type and location after loading were classified. Data were analyzed using one-way ANOVA and Tukey's test.Results: Significantly higher fracture strength was obtained in group 4 (330 +/- 81 N) compared to the controls in group 1 (179 +/- 120 N) (one-way ANOVA, p < 0.05). Group lb survived a lower mean number of cyclic loads (672,820 cycles) than teeth of groups 2b to 4b (846x10(3) to 873x10(3) cycles). Failure type evaluation after the fracture test showed predominantly adhesive failures between dentin and cement, but after cyclic loading, more cohesive fractures in the ceramic were seen.Conclusion: Ceramic laminate veneers bonded to conditioned aged composite restorations provided favorable results. Surface conditioning of existing restorations may eliminate the necessity of removing aged composite restorations.

Evaluation of Bond Strength of Self-adhesive Cements to Dentin With or Without Application of Adhesive Systems

Purpose: To evaluate the bond strength of indirect restorations to dentin using self-adhesive cements with and without the application of adhesive systems.Material and Methods: Seventy-two bovine incisors were used, in which the buccal surfaces were ground down to expose an area of dentin measuring a minimum of 4 x 4 mm. The indirect resin composite Resilab was used to make 72 blocks, which were cemented onto the dentin surface of the teeth and divided into 4 groups (n = 18): group 1: self-adhesive resin cement BiFix SE, applied according to manufacturer's recommendations; group 2: self-adhesive resin cement RelyX Unicem, used according to manufacturer's recommendations; group 3: etch-and-rinse Solobond M adhesive system + BiFix SE; group 4: etch-and-rinse Single Bond 2 adhesive system + RelyX Unicem. The specimens were sectioned into sticks and subjected to microtensile testing in a universal testing machine (EMIC DL-200MF). Data were subjected to one-way ANOVA and Tukey's test (alpha = 5%).Results: The mean values (+/- standard deviation) obtained for the groups were: group 1: 15.28 (+/- 8.17)(a), group 2: 14.60 (+/- 5.21)(a), group 3: 39.20 (+/- 9.98)(c), group 4: 27.59 (+/- 6.57)(b). Different letters indicate significant differences (ANOVA; p = 0.0000).Conclusion: The application of adhesive systems before self-adhesive cements significantly increased the bond strength to dentin. In group 2, RelyX Unicem associated with the adhesive system Single Bond 2 showed significantly lower mean tensile bond strengths than group 3 (BiFix SE associated with the etch-and-rinse Solobond M adhesive system).