Introdução à teoria de Poincaré-Bendixson para campos de vetores planares

O Teorema de Poincaré-Bendixson é um resultado muito importante no estudo de Sistemas Dinâmicos, pois ele estabelece para quais tipos de conjunto limite as trajetórias de um campo de vetores em IR2 deve convergir. Neste trabalho vamos abordar a Funç˜ao do primeiro Retorno de Poincaré, além de discutir a estabilidade de Ciclos Limites e provar o Teorema de Poincaré-Bendixson.

Classification and regression tree (CART) model to predict pulmonary tuberculosis in hospitalized patients

Background: Tuberculosis (TB) remains a public health issue worldwide. The lack of specific clinical symptoms to diagnose TB makes the correct decision to admit patients to respiratory isolation a difficult task for the clinician. Isolation of patients without the disease is common and increases health costs. Decision models for the diagnosis of TB in patients attending hospitals can increase the quality of care and decrease costs, without the risk of hospital transmission. We present a predictive model for predicting pulmonary TB in hospitalized patients in a high prevalence area in order to contribute to a more rational use of isolation rooms without increasing the risk of transmission. Methods: Cross sectional study of patients admitted to CFFH from March 2003 to December 2004. A classification and regression tree (CART) model was generated and validated. The area under the ROC curve (AUC), sensitivity, specificity, positive and negative predictive values were used to evaluate the performance of model. Validation of the model was performed with a different sample of patients admitted to the same hospital from January to December 2005. Results: We studied 290 patients admitted with clinical suspicion of TB. Diagnosis was confirmed in 26.5% of them. Pulmonary TB was present in 83.7% of the patients with TB (62.3% with positive sputum smear) and HIV/AIDS was present in 56.9% of patients. The validated CART model showed sensitivity, specificity, positive predictive value and negative predictive value of 60.00%, 76.16%, 33.33%, and 90.55%, respectively. The AUC was 79.70%. Conclusions: The CART model developed for these hospitalized patients with clinical suspicion of TB had fair to good predictive performance for pulmonary TB. The most important variable for prediction of TB diagnosis was chest radiograph results. Prospective validation is still necessary, but our model offer an alternative for decision making in whether to isolate patients with clinical suspicion of TB in tertiary health facilities in countries with limited resources.

Prey digestion in the midgut of the predatory bug Podisus nigrispinus (Hemiptera: Pentatomidae)

Pre-oral digestion is described as the liquefaction of the solid tissues of the prey by secretions of the predator. It is uncertain if pre-oral digestion means pre-oral dispersion of food or true digestion in the sense of the stepwise bond breaking of food polymers to release monomers to be absorbed. Collagenase is the only salivary proteinase, which activity is significant (10%) in relation to Podisus nigrispinus midgut activities. This suggests that pre-oral digestion in P. nigrispinus consists in prey tissue dispersion. This was confirmed by the finding of prey muscles fibers inside P. nigrispinus midguts. Soluble midgut hydrolases from P. nigrispinus were partially purified by ion-exchange chromatography, followed by gel filtration. Two cathepsin L-like proteinases (CAL1 and CAL2) were isolated with the properties: CAL1 (14.7 kDa, pH optimum (pHo) 5.5, km with carbobenzoxy-Phe-Arg-methylcoumarin, Z-FR-MCA, 32 mu M); CAL2 (17 kDa, pHo 5.5, km 11 mu M Z-FR-MCA). Only a single molecular species was found for the other enzymes with the following properties are: amylase (43 kDa, pHo 5.5, km 0.1% starch), aminopeptidase (125 kDa, pHo 5.5, km 0.11 mM L-Leucine-p-nitroanilide), alpha-glucosidase (90 kDa, pHo 5.0, km 5 mM with p-nitrophenyl alpha-D-glucoside). CAL molecular masses are probably underestimated due to interaction with the column. Taking into account the distribution of hydrolases along P. nigrispinus midguts, carbohydrate digestion takes place mainly at the anterior midgut, whereas protein digestion occurs mostly in middle and posterior midgut, as previously described in seed- sucker and blood-feeder hemipterans. (C) 2012 Elsevier Ltd. All rights reserved.

Validation of reference genes for RT-qPCR normalization in common bean during biotic and abiotic stresses

Selection of reference genes is an essential consideration to increase the precision and quality of relative expression analysis by the quantitative RT-PCR method. The stability of eight expressed sequence tags was evaluated to define potential reference genes to study the differential expression of common bean target genes under biotic (incompatible interaction between common bean and fungus Colletotrichum lindemuthianum) and abiotic (drought; salinity; cold temperature) stresses. The efficiency of amplification curves and quantification cycle (C (q)) were determined using LinRegPCR software. The stability of the candidate reference genes was obtained using geNorm and NormFinder software, whereas the normalization of differential expression of target genes [beta-1,3-glucanase 1 (BG1) gene for biotic stress and dehydration responsive element binding (DREB) gene for abiotic stress] was defined by REST software. High stability was obtained for insulin degrading enzyme (IDE), actin-11 (Act11), unknown 1 (Ukn1) and unknown 2 (Ukn2) genes during biotic stress, and for SKP1/ASK-interacting protein 16 (Skip16), Act11, Tubulin beta-8 (beta-Tub8) and Unk1 genes under abiotic stresses. However, IDE and Act11 were indicated as the best combination of reference genes for biotic stress analysis, whereas the Skip16 and Act11 genes were the best combination to study abiotic stress. These genes should be useful in the normalization of gene expression by RT-PCR analysis in common bean, the most important edible legume.

Endophytic fungi from the Amazonian plant Paullinia cupana and from Olea europaea isolated using cassava as an alternative starch media source

Endophytic fungi live inside plants, apparently do not cause any harm to their hosts and may play important roles in defense and growth promotion. Fungal growth is a routine practice at microbiological laboratories, and the Potato Dextrose Agar (PDA) is the most frequently used medium because it is a rich source of starch. However, the production of potatoes in some regions of the world can be costly. Aiming the development of a new medium source to tropical countries, in the present study, we used leaves from the guarana (a tropical plant from the Amazon region) and the olive (which grows in subtropical and temperate regions) to isolate endophytic fungi using PDA and Manihot Dextrose Agar (MDA). Cassava (Manihot esculenta) was evaluated as a substitute starch source. For guarana, the endophytic incidence (EI) was 90% and 98% on PDA and MDA media, respectively, and 65% and 70% for olive, respectively. The fungal isolates were sequenced using the ITS- rDNA region. The fungal identification demonstrated that the isolates varied according to the host plant and media source. In the guarana plant, 13 fungal genera were found using MDA and six were found using PDA. In the olive plant, six genera were obtained using PDA and 4 were obtained using MDA. The multivariate analysis results demonstrated the highest fungal diversity from guarana when using MDA medium. Interestingly, some genera were isolated from one specific host or in one specific media, suggesting the importance of these two factors in fungal isolation specificity. Thus, this study indicated that cassava is a feasible starch source that could serve as a potential alternative medium to potato medium.

Q. Curtius Rufus ad codices parisinos recensitus cum varietate lectionum, supplementis Jo. Freinshemii et selectis Schmiederi variorumque commentariis quibus notas, excursus mappasque et indices addidit N. E. Lemaire.

Vol. 3 has title: Q. Curtius Rufus ad codices parisinos recensitus cum itinerario Alexandri, et Julio Valerio. Æsopi græci translatore quibus apud nos primum editis novos excursus, mappas, imagines, catalogos et indices ... addidit N. E. Lemaire ... "Index editionum [et versionum] Q. Curtii Rufi": v. 3, p. [375]-400.

[Q. Curtii Rufi, Historia Alexandri Magni /

J. Freinshemii Supplementorum in Q. Curtium liber primus [-secundus], p. 1-93.

Q. Curtii Rufi De rebus gestis Alexandri Magni historia

NC 0847652

Q. Curtius Rufus De rebus Alexandri Magni : una cum supplementis ... /

Mode of access: Internet.

Q. Horatii Flacci Opera omnia /

Mode of access: Internet.

Q. Curtii Rufi De rebus gestis Alexandri Magni regis Macedonum : libri superstites ad optimorum exemplarium fidem recensiti atque prooemio et indice rerum instructi a Frid. Schmieder.

Includes index.

Effect after introducing Bacillus thuringiensis gene on nitrogen metabolism in cotton

Bacillus thuringiensis (Bt) transgenic cotton has shown changes of vegetative and reproductive growth characteristics. The objective of this study was to investigate the physiological change of nitrogen metabolism that related closely to the growth in Bt cotton cultivars. The study Was undertaken on two 131 transgenic cotton cultivars and their parents, one conventional (Xingyang822) and recurrent parent (Sumian No. 9), the other a hybrid (Kumian No. 1) and female parent (Yumian No. 1), during the 2001 and 2002 growing seasons at the Yangzhou University Farm, Yangzhou, China. In the 2001 study, The results indicated that the Bt cotton cultivars were higher than their parents in leaf total nitrogen, free amino acid and soluble protein content, greater in NR and GPT activity, and lower in protease activity, during peak square and boll developing period. The biggest increase of total nitrogen was at peak boll period, which increased by 36.01 and 18.96% for Kumian No. I and Xingyang822, respectively. There were similar results for free amino acid and soluble protein content. The results showed further in 2002 study that NR activity increased dramatically at peak square and early boll open period, the biggest increase at early boll open period, with Kumian No. I and Xingyan,822 being 87.5 and 61.4% higher than their parent, respectively, the biggest increase of GPT activity was at peak boll period, with Kumian No. I and Xingyang822 being 39.1 and 29.1% higher than their parent, respectively. However, protease activity of Bt cultivars reduced significantly before flowering and early boll open period, the biggest decrease was before flowering period, with Kumian No. I being more than 30%, Xingyang822 being 26.5% at peak square period. Moreover, the boll total nitrogen content reduced sharply. The results suggest that the Bt cotton cultivars have higher intensity of leaf nitrogen metabolism than their parent, especially during square and boll development period. It is disadvantage for square development and earlier boll maturity under high nitrogen condition. The cultural practice should aim at reducing leaf nitrogen metabolic strength and keep the balance of vegetative and reproductive growth. (C) 2003 Elsevier B.V. All rights reserved.

The effect of high temperature on the insecticidal properties of Bt Cotton

Bt transgenic cotton has not shown the same level of resistance to bollworm in China, as in other major Bt cotton growing areas of the world. The objective of this study was to investigate the effects of high temperature on the CryIA insecticidal protein content and nitrogen metabolism, in the leaf of Bt transgenic cotton. The study was undertaken on two transgenic cotton cultivars, one conventional (Xinyang 822) and the other a hybrid (Kumian No. 1), during the 2001 and 2002 growing seasons at the Yangzhou University Farm, Yangzhou, China. In the 2001 study, potted cotton plants were exposed to 37 C for 24 h under glasshouse conditions at three growth stages peak square, peak flowering and peak boll developing periods. Based on the 2001 results, in 2002 the same two cultivars were exposed to the same temperature for 48 h at two growth stages-peak flowering and boll developing periods. The results of the study indicated that the insecticidal protein content of the leaf was not significantly affected by the stress during the square and flowering periods. However, exposure to high temperature for 24h during the boll period reduced the CryIA protein content by approximately 51% in the cultivar Kumian No 1, and 30% in Xinyang 822 in the 2001 study, and by approximately 73 and 63% for 48 h with the same cultivars, respectively, in the 2002 study. Glutamic-pyruvic transaminase (GPT) activity, total free amino acid and soluble protein content, and the activity of protease in the leaf, showed relatively little change in response to high temperature in the flowering period. However, exposure to high temperature in the boll period resulted in the following changes - a reduction of GPT activity, a sharp increase in free amino acid content, a significant decrease in soluble protein content, and significant increases in the activity of protease. The results suggest that high temperature may result in the degradation of soluble protein in the leaf, with a resulting decline in the level of the toxin CryIA. It is believed that this may be the cause of the reduced efficacy of Bt cotton in growing conditions in China, where temperatures during the boll period often reach 36-40° C. © 2004 Elsevier B.V All rights reserved.

Anisotropy for spatial summation of elongated patches of grating:A tale of two tails

Studies of spatial summation often use sinusoidal gratings with blurred edges. When the envelope is elongated (i) along the grating stripes and (ii) at right angles to the grating stripes, we refer to the stimuli as skunk-tails and tiger-tails respectively. Previous work [Polat & Tyler, 1999; Vision Research, 39, 887-895.] has found that sensitivity to skunk-tails is greater than for tiger-tails, but there have been several failures to replicate this result within a subset of the conditions. To address this we measured detection thresholds for skunk-tails, tiger-tails and squares of grating with sides matched to the lengths of the tails. For foveal viewing, we found a contrast sensitivity advantage in the order of 2 dB for skunk-tails over tiger-tails, but only for horizontal gratings. For vertical gratings, sensitivity was very similar for both tail-types. When the stimuli were presented parafoveally (upper right visual field), a small advantage was found for skunk-tails over tiger-tails at both orientations, and spatial summation slopes were close to that of the ideal observer. We did not replicate the findings of Polat & Tyler, but our results are consistent with (i) those of Foley et al. [Foley, J. M., Varadharajan, S., Koh, C. C., & Farias, C. Q. (2007) Vision Research, 47, 85-107.] who used only vertical gratings and (ii) those from modelfest, where only horizontal gratings were used. The small effect of tail-type here suggests an anisotropy in the underlying physiology. © 2007 Elsevier Ltd. All rights reserved.