Resource partitioning and ecomorphological variation in two syntopic species of Lebiasinidae (Characiformes) in an Amazonian stream

ABSTRACTResource partitioning is important for species coexistence. Species with similar ecomorphology are potential competitors, especially when phylogenetically close, due to niche conservatism. The aim of this study was to investigate the resource partitioning among populations of two species of lebiasinids (Copella nigrofasciata and Pyrrhulina aff. brevis) that co-occur in a first-order Amazonian stream, analyzing the trophic ecology, feeding strategies and ecomorphological attributes related to the use of food and space by these species. Fish were captured in May and September 2010. The stomach contents of 60 individuals were analyzed and quantified volumetrically to characterize the feeding ecology of both species. Eleven morphological attributes were measured in 20 specimens and combined in nine ecomorphological indices. Both species had an omnivorous-invertivorous diet and consumed predominantly allochthonous items. Both showed a tendency to a generalist diet, but intrapopulational variation in resource use was also detected. Overall feeding niche overlap was high, but differed between seasons: low during the rainy season and high in the dry season. In the latter, the food niche overlap was asymmetric because C. nigrofasciata consumed several prey of P. aff. brevis, which reduced its food spectrum. The ecomorphological analysis suggests that C. nigrofasciatahas greater swimming capacity (greater relative length of caudal peduncle) than P. aff. brevis, which has greater maneuverability and tendency to inhabit lentic environments (greater relative depth of the body). Our results demonstrate that these species have similar trophic ecology and suggest a spatial segregation, given by morphological differences related to locomotion and occupation of habitat, favoring their coexistence.

RNA-seq analysis of the Quercus suber root response to drought

Dissertação de mestrado em Plant Molecular Biology, Biotechnology and Bioentrepreneurship

Big data e data analysis: visualização de informação

Dissertação de mestrado integrado em Engenharia e Gestão de Sistemas de Informação

Lewis Score - Prognostic value in patients with isolated small bowel Crohn's disease

Background and aims: Small bowel capsule endoscopy (SBCE) allows mapping of small bowel inflammation in Crohn’s disease (CD). We aimed to assess the prognostic value of the severity of inflammatory lesions, quantified by the Lewis score (LS), in patients with isolated small bowel CD. Methods: A retrospective study was performed in which 53 patients with isolated small bowel CD were submitted to SBCE at the time of diagnosis. The Lewis score was calculated and patients had at least 12 months of follow-up after diagnosis. As adverse events we defined disease flare requiring systemic corticosteroid therapy, hospitalization and/or surgery during follow-up. We compared the incidence of adverse events in 2 patient subgroups, i.e. those with moderate or severe inflammatory activity (LS =790) and those with mild inflammatory activity (135 = LS < 790). Results: The LS was =790 in 22 patients (41.5%), while 58.5% presented with LS between 135 and 790. Patients with a higher LS were more frequently smokers (p = 0.01), males (p = 0017) and under immunosuppressive therapy (p = 0.004). In multivariate analysis, moderate to severe disease at SBCE was independently associated with corticosteroid therapy during follow-up, with a relative risk (RR) of 5 (p = 0.011; 95% confidence interval [CI] 1.5–17.8), and for hospitalization, with an RR of 13.7 (p = 0 .028; 95% CI 1.3–141.9). Conclusion: In patients with moderate to severe inflammatory activity there were higher prevalences of corticosteroid therapy demand and hospitalization during follow-up. Thus, stratifying the degree of small bowel inflammatory activity with SBCE and LS calculation at the time of diagnosis provided relevant prognostic value in patients with isolated small bowel CD.

Predictive value of clinical and electrophysiological variables in patients with chronic chagasic cardiomyopathy and nonsustained ventricular tachycardia

OBJECTIVE: Risk stratification of patients with nonsustained ventricular tachycardia (NSVT) and chronic chagasic cardiomyopathy (CCC). METHODS: Seventy eight patients with CCC and NSVT were consecutively and prospectively studied. All patients underwent to 24-hour Holter monitoring, radioisotopic ventriculography, left ventricular angiography, and electrophysiologic study. With programmed ventricular stimulation. RESULTS: Sustained monomorphic ventricular tachycardia (SMVT) was induced in 25 patients (32%), NSVT in 20 (25.6%) and ventricular fibrillation in 4 (5.1%). In 29 patients (37.2%) no arrhythmia was inducible. During a 55.7-month-follow-up, 22 (28.2%) patients died, 16 due to sudden death, 2 due to nonsudden cardiac death and 4 due to noncardiac death. Logistic regression analysis showed that induction was the independent and main variable that predicted the occurrence of subsequent events and cardiac death (probability of 2.56 and 2.17, respectively). The Mantel-Haenszel chi-square test showed that survival probability was significantly lower in the inducible group than in the noninductible group. The percentage of patients free of events was significantly higher in the noninducible group. CONCLUSION: Induction of SMVT during programmed ventricular stimulation was a predictor of arrhythmia occurrence cardiac death and general mortality in patients with CCC and NSVT.

Prognostic value of technetium-99m-labeled single-photon emission computerized tomography in the follow-up of patients after their first myocardial revascularization surgery

OBJECTIVE: To assess the prognostic value of Technetium-99m-labeled single-photon emission computerized tomography (SPECT) in the follow-up of patients who had undergone their first myocardial revascularization. METHODS: We carried out a retrospective study of 280 revascularized patients undergoing myocardial scintigraphy under stress (exercise or pharmacological stress with dipyridamole) and at rest according to a 2-day protocol. A set of clinical, stress electrocardiographic and scintigraphic variables was assessed. Cardiac events were classified as "major" (death, infarction, unstable angina) and "any" (major event or coronary angioplasty or new myocardial revascularization surgery). RESULTS: Thirty-six major events occurred as follows: 3 deaths, 11 infarctions, and 22 unstable anginas. In regard to any event, 22 angioplasties and 7 new surgeries occurred in addition to major events, resulting a total of 65 events. The sensitivity of scintigraphy in prognosticating a major event or any event was, respectively, 55% and 58%, showing a negative predictive value of 90% and 83%, respectively. Diabetes mellitus, inconclusive stress electrocardiography, and a scintigraphic visualization of left ventricular enlargement were significant variables for the occurrence of a major event. On multivariate analysis, abnormal myocardial scintigraphy was a predictor of any event. CONCLUSION: Myocardial perfusion tomography with Technetium-99m may be used to identify high-risk patients after their first myocardial revascularization surgery.

Acoustic emission analysis of the effect of a 2D wedge shaped blade on the compact bone cutting process

Surgeons may use a number of cutting instruments such as osteotomes and chisels to cut bone during an operative procedure. The initial loading of cortical bone during the cutting process results in the formation of microcracks in the vicinity of the cutting zone with main crack propagation to failure occuring with continued loading. When a material cracks, energy is emitted in the form of Acoustic Emission (AE) signals that spread in all directions, therefore, AE transducers can be used to monitor the occurrence and development of microcracking and crack propagation in cortical bone. In this research, number of AE signals (hits) and related parameters including amplitude, duration and absolute energy (abs-energy) were recorded during the indentation cutting process by a wedge blade on cortical bone specimens. The cutting force was also measured to correlate between load-displacement curves and the output from the AE sensor. The results from experiments show AE signals increase substantially during the loading just prior to fracture between 90% and 100% of maximum fracture load. Furthermore, an amplitude threshold value of 64dB (with approximate abs-energy of 1500 aJ) was established to saparate AE signals associated with microcracking (41 – 64dB) from fracture related signals (65 – 98dB). The results also demonstrated that the complete fracture event which had the highest duration value can be distinguished from other growing macrocracks which did not lead to catastrophic fracture. It was observed that the main crack initiation may be detected by capturing a high amplitude signal at a mean load value of 87% of maximum load and unsteady crack propagation may occur just prior to final fracture event at a mean load value of 96% of maximum load. The author concludes that the AE method is useful in understanding the crack initiation and fracture during the indentation cutting process.

Prognostic Value of Pulmonary Vascular Resistance by Magnetic Resonance in Systolic Heart Failure

Abstract Background: Pulmonary hypertension is associated with poor prognosis in heart failure. However, non-invasive diagnosis is still challenging in clinical practice. Objective: We sought to assess the prognostic utility of non-invasive estimation of pulmonary vascular resistances (PVR) by cardiovascular magnetic resonance to predict adverse cardiovascular outcomes in heart failure with reduced ejection fraction (HFrEF). Methods: Prospective registry of patients with left ventricular ejection fraction (LVEF) < 40% and recently admitted for decompensated heart failure during three years. PVRwere calculated based on right ventricular ejection fraction and average velocity of the pulmonary artery estimated during cardiac magnetic resonance. Readmission for heart failure and all-cause mortality were considered as adverse events at follow-up. Results: 105 patients (average LVEF 26.0 ±7.7%, ischemic etiology 43%) were included. Patients with adverse events at long-term follow-up had higher values of PVR (6.93 ± 1.9 vs. 4.6 ± 1.7estimated Wood Units (eWu), p < 0.001). In multivariate Cox regression analysis, PVR ≥ 5 eWu(cutoff value according to ROC curve) was independently associated with increased risk of adverse events at 9 months follow-up (HR2.98; 95% CI 1.12-7.88; p < 0.03). Conclusions: In patients with HFrEF, the presence of PVR ≥ 5.0 Wu is associated with significantly worse clinical outcome at follow-up. Non-invasive estimation of PVR by cardiac magnetic resonance might be useful for risk stratification in HFrEF, irrespective of etiology, presence of late gadolinium enhancement or LVEF.

Comparative Analysis of Signals Restoration by Different Kinds of Approximation

The comparative analysis of continuous signals restoration by different kinds of approximation is performed. The software product, allowing to define optimal method of different original signals restoration by Lagrange polynomial, Kotelnikov interpolation series, linear and cubic splines, Haar wavelet and Kotelnikov-Shannon wavelet based on criterion of minimum value of mean-square deviation is proposed. Practical recommendations on the selection of approximation function for different class of signals are obtained.

Microsatellite genotyping from faeces of Lontra longicaudis from southern Brazil

A genetic study of the neotropical river otter Lontra longicaudis (Olfers, 1818), which has an unknown conservation status, was carried out at the Taim Ecological Station and the margins of the Vargas stream, Rio Grande do Sul, southern Brazil. Faecal samples were collected, and DNA was extracted using a silica-guanidine method. Five microsatellite loci were amplified using PCR with heterologous primers previously described for Lutra lutra (Linnaeus, 1758). Sixteen faecal samples out of 29 from Taim and 11 out of 14 from Vargas stream margins contained enough DNA for genetic analysis. A total of 49 different alleles were found at both localities, from which 18 were exclusively found in individuals from Taim and 17 were exclusives from Vargas individuals. The most common allele was the same at both locations for three loci (Lut715, Lut733, and Lut818). A high level of genetic diversity was found at both sites (NeTaim=4.1, HoTaim=0.299, HeTaim=0.681; NeVargas=4.9, HoVargas=0.355, HeVargas=0.724), being higher at the Vargas stream site. A high and significant level of heterozygote deficiency was observed at most loci according to the χ2 test. The homogeneity χ2 test (P<0.001) showed that there were significant differences in the allele frequencies between the two locations. Genotyping for more than one locus was possible in 81.5% of samples, from which only 37% were possible to genotype for more than three loci. A low degree of relatedness was found among individuals from Taim (R=0.055±0.310), but an even lower value of relatedness was found at the Vargas site (R= -0.285±0.440). The significant degree of differentiation (I=0.890; F ST=0.059) found between Taim and Vargas individuals suggests that there is more than one population of otters in the southern extreme of Brazil, which probably are associated with the water body systems found in this region, the Mirim and the Caiuvá/Flores/Mangueira Lagoons. The high genetic diversity and low relatedness found at the Vargas stream, lead us to believe that the Vargas stream may be acting as a corridor between these water bodies for otter dispersion.

Oligochaetes (Annelida, Clitellata) in a neotropical stream: a mesohabitat approach

This paper analyses the relationship among mesohabitat and aquatic oligochaete species in the Galharada Stream (Campos do Jordão State Park, state of São Paulo, Brazil). Between August 2005 and May 2006 a total of 192 samples were obtained in areas of four different mesohabitats: riffle leaf litter (RL), pool leaf litter (PL), pool sediment (PS) and interstitial sediment from rocky beds in riffle areas (IS). In the mesohabitats sampled, 2007 specimens were identified, belonging to two families (Naididae and Enchytraeidae). Among the oligochaetes identified Naididae was represented by six genera (Allonais, Chaetogaster, Nais, Pristina, Aulodrilus and Limnodrilus). Principal components analysis (PCA) revealed the first two axes explained 85.1% of the total variance of the data. Limnodrilus hoffmeisteri Claparede, 1862 and Aulodrilus limnobius Bretscher, 1899 were associated with the pool areas (PL and PS). Most species of genera Pristina and Nais demonstrated apparent affinity with the riffle mesohabitats. The Indicator Species Analysis (IndVal) revealed that Nais communis Piguet, 1906, Pristina leidyi Smith, 1896 and Pristina (Pristinella) jenkinae (Stephenson, 1931) are indicative of RL mesohabitat, while family Enchytraeidae was considered indicative of PL mesohabitat.

Trophic relationships between macroinvertebrates and fish in a pampean lowland stream (Argentina)

The diet and trophic relationships between the macroinvertebrates Phyllogomphoides joaquini Rodrigues Capítulo, 1992 and Coenagrionidae (Odonata), Chironomidae (Diptera), Diplodon delodontus (Lamarck, 1919) (Bivalvia: Hyriidae), and Pomacea canaliculata (Lamarck, 1822) (Gastropoda: Ampulariidae) and the fishes Pimelodella laticeps Eigenmann, 1917 (Heptapteridae) and Bryconamericus iheringii (Boulenger, 1887) (Characidae) in a temperate lowland lotic system in Argentina were assessed on the basis of gut contents and stable-isotope analyses. The feeding strategies were analyzed by the AMUNDSEN method. Relative food items contribution for the taxa studied indicated a generalist-type trophic strategy. In macroinvertebrates, in general, the values of stable isotope confirmed the result of the analysis of gut contents. With the fish, stable-isotope analysis demonstrated that both species are predators, although B. iheringii exhibited a more omnivorous behaviour. These feeding studies allowed us to determine the trophic relationships among taxa studied. Detritus and diatoms were a principal source of food for all the macroinvertebrates studied. In La Choza stream the particulate organic matter is a major no limited food resource, has a significant influence upon the community.

Ecomorphology and diet reflect the spatial segregation between two Siluriformes species inhabiting a stream of the Bodoquena Plateau, in Central Brazil

Pimelodella taenioptera Miranda Ribeiro, 1914 and Imparfinis schubarti (Gomes, 1956) are two of the most common fish species in Bodoquena Plateau streams, Paraguay basin. These species have benthic habits and subaquatical observations suggested that they present differentiation in their preference for mesohabitat types. Pimelodella taenioptera shows preference for slow waters, such as pools, while I. schubarti is associated to riffles. In this study we investigated if the known patterns of mesohabitat use of P. taenioptera and I. schubarti can be predict by their ecomorphological and trophic traits. We described the dietary habits and ecomorphological attributes of P. taenioptera and I. schubarti individuals, captured in the Parque Nacional da Serra da Bodoquena (PNSB), Mato Grosso do Sul state, central Brazil. Pimelodella taenioptera presented a more generalist diet, consuming a total of 23 different food items. Imparfinis schubarti have a diet based exclusively on aquatic insects. The ecomorphological analysis revealed that the species differed in relation to five morphological traits associated to habitat use (p <0.01). The results of this study reveal a clear functional dissimilarity between P. taenioptera and I. shubarti. The observed trophic and ecomorphological patterns are congruent with the known habitat use for these species and probably reflect the spatial and temporal variability on conditions and resources present in riffles and pools. Therefore, as expected, the morphological and feeding attributes represent predictive information related to mesohabitat use.

Assemblage of immature Odonata (Insecta, Anisoptera) in streams of the Mato Grosso do Sul State: spatial implications

ABSTRACT This study investigated the assemblages attributes (composition, abundance, richness, diversity and evenness) and the most representative genera of Odonata, Anisoptera at Água Boa and Perobão Streams, Iguatemi River basin, Brazil. Both are first order streams with similar length that are impacted by riparian forest removal and silting. Quarterly samplings were conducted from March to December 2008 in the upper, intermediate and lower stretch of each stream. The Mantel test was used to check the influence of spatial autocorrelation on the Odonata composition. Spatial variations in the composition were summarized by the Principal Coordinates Analysis (PCoA) using Mantel test residuals. The effects of spatial correlation on richness and abundance were investigated by the spatial correlogram of Moranʼs I coefficients. The most representative genera in each stream were identified by the Indicator Value Method. The spatial variations in the attributes of the assemblages were assessed using analysis of variance of null models. We collected 500 immature individuals of 23 genera and three families. Among the attributes analyzed only the composition and abundance showed significant spatial differences, with the highest mean abundance found in the Perobão Stream. Miathyria and Zenithoptera were the indicator genera of the Água Boa Stream and Erythrodiplax, Libellula, Macrothemis, Progomphus and Tramea were the indicator genera of the Perobão Stream.

A Methodology to measure shareholder value orientation and shareholder value creation aimed at providing a research basis to investigate the link between both magnitudes

Does shareholder value orientation lead to shareholder value creation? This article proposes methods to quantify both, shareholder value orientation and shareholder value creation. Through the application of these models it is possible to quantify both dimensions and examine statistically in how far shareholder value orientation explains shareholder value creation. The scoring model developed in this paper allows quantifying the orientation of managers towards the objective to maximize wealth of shareholders. The method evaluates information that comes from the companies and scores the value orientation in a scale from 0 to 10 points. Analytically the variable value orientation is operationalized expressing it as the general attitude of managers toward the objective of value creation, investment policy and behavior, flexibility and further eight value drivers. The value creation model works with market data such as stock prices and dividend payments. Both methods where applied to a sample of 38 blue chip companies: 32 firms belonged to the share index IBEX 35 on July 1st, 1999, one company represents the “new economy” listed in the Spanish New Market as per July 1st, 2001, and 5 European multinational groups formed part of the EuroStoxx 50 index also on July 1st, 2001. The research period comprised the financial years 1998, 1999, and 2000. A regression analysis showed that between 15.9% and 23.4% of shareholder value creation can be explained by shareholder value orientation.