Papers by Fernando Gonçalves
Relationship between severity of clinical symptoms and delay in gastric emptying in chronic gastritis; studied with 99m Tc-DTPA scintigraphy
European Journal of Nuclear Medicine, 1986
The gastric emptying time is studied with 99mTC-DTPA-labeled mixed meal in 18 patients with chron... more The gastric emptying time is studied with 99mTC-DTPA-labeled mixed meal in 18 patients with chronic gastritis, all confirmed by endoscopic examination and biopsy. Emptying was slow in all such patients, but the intensity of symptomatology showed no correlation with gastric emptying half time.
Journal of Heuristics, 2002
This paper presents a hybrid genetic algorithm for the simple assembly line problem, SALBP-1. The... more This paper presents a hybrid genetic algorithm for the simple assembly line problem, SALBP-1. The chromosome representation of the problem is based on random keys. The assignment of the operations to the workstations is based on a heuristic priority rule in which the priorities of the operations are defined by the chromosomes. A local search is used to improve the solution. The approach is tested on a set of problems taken from the literature and compared with other approaches. The computation results validate the effectiveness of the algorithm.
IEEE Transactions on Nuclear Science, 2006
The design and evaluation of the imaging system Clear-PEM for positron emission mammography, unde... more The design and evaluation of the imaging system Clear-PEM for positron emission mammography, under development by the PEM Consortium within the framework of the Crystal Clear Collaboration at CERN, is presented. The proposed apparatus is based on fast, segmented, high atomic number radiation sensors with depth-of-interaction measurement capabilities, and state-of-the-art data acquisition techniques. The camera consists of two compact and planar detector heads with dimensions 16.5 14.5 cm 2 for breast and axilla imaging. Low-noise integrated electronics provide signal amplification and analog multiplexing based on a new data-driven architecture. The coincidence trigger and data acquisition architecture makes extensive use of pipeline processing structures and multi-event memories for high efficiency up to a data acquisition rate of one million events/s. Experimental validation of the detection techniques, namely the basic properties of the radiation sensors and the ability to measure the depth-of-interaction of the incoming photons, are presented. System performance in terms of detection sensitivity, count-rates and reconstructed image spatial resolution were also evaluated Manuscript by means of a detailed Monte Carlo simulation and an iterative image reconstruction algorithm.
Plasticity of the sensorimotor cortex representation of the reading finger in Braille readers
Brain, 1993
We studied the organization of the somatosensory cortex in proficient Braille readers, recording ... more We studied the organization of the somatosensory cortex in proficient Braille readers, recording somatosensory evoked potentials (SEPs) in 10 subjects and using transcranial magnetic stimulation (TMS) in five subjects, and compared the results with those of 15 control subjects. Somatosensory evoked potentials were elicited by a focal electrical stimulus to the tip of the index finger and recorded from a contralateral 4 x 4 grid of scalp electrodes centred around C3' and C4'. Transcranial magnetic stimulation, with an 8-shaped coil centred over the same scalp positions, was delivered simultaneously with, and at different intervals after, the finger stimulus. The results of the right index (reading) finger in Braille readers were compared with those of their left index (non-reading) finger and of the right and left index fingers of the control subjects. The scalp areas from which we recorded N20 and P22 components of the SEP with an amplitude of at least 70% of the maximal amplitude recorded in each trial were significantly larger in SEPs evoked from the reading fingers. Detection of the stimulus applied to the reading finger was blocked by TMS delivered over a larger contralateral scalp area and during a longer time window after the stimulus. These experiments suggest that reading Braille is associated with expansion of the sensorimotor cortical representation of the reading finger.
Clinical Manifestations in Children with Occipital Spike-Wave Paroxysms
Epilepsia, 1992
Summary: The pattern of occipital-posterotemporal spike-wave paroxysms (O-PT SWPs), is a distinct... more Summary: The pattern of occipital-posterotemporal spike-wave paroxysms (O-PT SWPs), is a distinctive EEG abnormality observed primarily with occipital epilepsy of childhood and basilar artery migraine. We studied EEG and clinical features in 30 children and young adults with this EEG pattern. Prolonged and brief O-PT SWPs were observed. Prolonged discharges (>6 s) were observed only in children with seizures (p < 0.001), and brief discharges (1–6 s) were observed immediately after eye closure. Generalized SWPs (11 patients, 37%) and background abnormalities (17 patients, 57%) were common. Photic activation of O-PT SWPs was not observed. Twenty-four patients (80%) manifested paroxysmal phenomena-seizures (20 patients, 67%) and migraine (12 patients, 40%, 4 alone and 8 with seizures). Fifteen patients (75%) had partial seizures, and 5 (25%) had absence seizures. In 7 patients with partial seizures, an etiology was evident. Neurologic examination was more often abnormal in patients with secondary partial seizures than in those with idiopathic partial seizures (p < 0.05) and absence seizures. Conversely, migraine was more often associated with idiopathic partial seizures than with secondary partial seizures (p < 0.05) and absence seizures. Six children (20%) had no paroxysmal events. Generalized SWPs were uncommon in patients with idiopathic partial seizures. We conclude that 0-PT SWPs is a nonspecific epileptiform abnormality that may occur in children with (a) idiopathic partial, (b) symptomatic partial, and (c) absence epilepsies, but it may also occur in patients with no evidence of seizures.Les pointes-ondes occipitales ou temporales postérieures (PO-OTP) représentent une anomalie électroencéphalographique typique observée surtout chez des enfants présentant une épilepsie occipitale et une migraine basilaire. Le auteurs ont étudié les caractéristiques EEG et cliniques de 30 enfants et adultes jeunes présentant ce pattern EEG. Ils ont observé des PO-OTP prolongées et brèves. Les décharges prolongées (7gt;6 sencondes) n'étaient constatées que chez des enfants présentant des crises (p gt; 0.001), les décharges brèves (1 à 6 secondes) étaient observées immédiatement après fermeture des yeux. Des PO généralisées (11 Patients, 37%) et des anomalies de l'activité de fond (17 patients, 57%) étaient fréquemment retrouvées. L'activation des PO-OTP par la SLI n'a pas été constatée. Vingt-quatre patients (80%) ont présenté des manifestations paroxystiques: crises (20 patients, 67%), et migraines (12 patients, 40%, 4 migraines insolées et 8 migraines associées à des crises). Quinze patients (75%) avaient des crises partielles (75%) et 5 (25%) des absences. Chez 7 patients présentant des crises partielles une étiologie a été retrouvée. L'examen neurologique était plus souvent anormal chez les patients présentant des crises partielles symptomatiques que chez ceux présentant des crises partielles idiopathiques (p < 0.05) et des absences. Inversement, la migraine est plus souvent associée avec des crises partielles idiopathiques qu'avec des crises partielles symptomatiques (p < 0.05) et des absences. Six enfants (20%) ne présentaient pas de phénomènes paroxystiques. Des PO généralisées étaient rares chez les patients présentant des crises partielles idiopathiques. Les auteurs concluent que les PO-OTP sont une anomalie épileptiforme non spécifique et peuvent être recontrées chez des enfants présentant 1) une épilepsie partielle idiopathique, 2) une épilepsie partielle symptomatique, 3) une épilepsie-absence. Cependant, on peut également constater ces anomalies chez des patients ne présentant pas de crises.El patrón de los paroxismos punta-onda en región occipitaltemporal posterior (O-PT SWPs), es una anormalidad electroencefalográfica distinat que es observa fundamentalmente en la epilepsía occipital de la infancia y en la migraña de la arteria basilar. Los autores estudian los datos electroencefalográficos y clínicos en 30 niños y adultos jóvenes con el citado patrón en el EEG. Se observaron prolongados y breves O-PT SWPs. Las descargas prolongadas (gt;6 segundos) se observaron solamente en niños con ataques (p < 0.001) y las descargas breves (1–6 segundos) se registraron inmediatamente después de cerrar los ojos. Los SWPs generalizados (11 enfermos; 37%) y las anormalidades de la actividad de fondo (17; 57%) fueron registradas con frecuencia. No se observó activación fótica de los O-PT SWPs. Veinticuatro enfermos (80%) manifestaron fenómenos paroxísticos (20 pacientes; 67%) y jaqueca (12 casos; 40%, 4 con ataques y 8 sin ataques). Quince enfermos (75%) tenían ataques parciales y 5 (25%) ausencias. En 7 pacientes cn ataques parciales se encontró una causa. El examen neurológico fue más frecuentemetne anormal en pacientes con ataques secundarios parciales que en aquellos que padecían ataques parciales idiopáticos (p < 0.05) y ausencias. Por el contrario la jaqueca se asoció más frecuentemente con los ataques parciales idiopáticos que con los parciales secundarios (p < 0.05) y las ausencias. Seis niños (20%) no mostraron acontecimientos paroxísticos. Los SWPs generalizados fueron poco comunes en enfermos con ataques parciales idiopáticos. Los autores concluyen que los O-PT SPWs, es una anomalía epileptiforme no específica que puede ser observada en niños con ataques 1) parciales idiopáticos, 2) parciales sintomáticos y 3) ausencias epilépticas. Sin embargo, también puede ser observado en pacientes sin evidencia de ataques.Occipitale bzw. posterior temporale spike wave Paroxysmen (OPT SWP) stellen sien encephalographische Besonderheit dar, die bei Kindern mit occipitaler Epilepsie und Basilaris-Migräne beobachtet werden. Wir untersuchten die encephalographischen und klinischen Zeichen bei 30 Kindern und jungen Erwachsenen mit diesem EEG-Muster. Es wurden prolongierte und kurze OPT SWT beobachtet. Prolongierte Entladungen (gt;6 sek.) nur unmittelbar nach Augenschluβ gesehen wurden. Generalisierte SWP (11 Patienten = 37%) und pathologische Grundaktivität (17 Patienten = 57%) traten häufig auf. Aktivierung durch Fotostimulation wurde nicht beobachtet. 24 Patienten (80%) boten paroxysmale Phänomene: Bei 20 Patienten Anfälle (67%), bei 12 Patienten Migräne (40%). 15 Patienten (75%) zeigten Partialanfälle und 5 Patienten Absencen (25%). Bei 7 Patienten mit Partialanfällen konnte eine Ursache gefunden werden. Die neurologische Untersuchung war häufiger auffällig bei Patienten mit sekundären Partialanfällen als bei Patienten mit idiopathischen Anfällen oder Absencen (p < 0.05). Dagegen war die Migräne öfters mit idiopathischen Anfällen als mit sekundären Anfällen oder Absencen assoziiert (p < 0.05). 6 Kinder (20%) hatten keine paroxysmalen Störungeen. Generalisierte SWP waren bei Patienten mit idiopathischen Partialanfällen ungewöhnlich. Daraus schlieβen wir, daβ OPT SWP eine unspezifische epileptische Erscheinung ist und beobachtet werden kann bei: (1) idiopathischen Partialanfällen; (2) symptomatischen Partialanfällen; (3) Absence. Darüberhinaus werden sie auch bei Patienten ohne Anfälle gesehen.
Journal of Heart and Lung Transplantation, 1999
Background: Single-lung transplantation for emphysema may be complicated by acute native lung hyp... more Background: Single-lung transplantation for emphysema may be complicated by acute native lung hyperinflation (ANLH) with hemodynamic and ventilatory compromise. Some groups advocate the routine use of independent lung ventilation, double-lung transplant, or right-lung transplant with or without contralateral lung volume reduction surgery in high-risk patients. The goal of this study was to determine the incidence of ANLH and identify its potential predictors.
Fems Microbiology Letters, 2004
During our screening of amylolytic microorganisms from Brazilian fruits, we isolated a yeast stra... more During our screening of amylolytic microorganisms from Brazilian fruits, we isolated a yeast strain classified as Cryptococcus flavus. When grown on starch-containing medium this strain exhibited the highest amylase production after 24 h of cultivation. The extracellular amylase from C. flavus was purified from the culture broth by a single step using chromatography on a Sephacryl S-100 column. The enzyme was purified 16.14-fold with a yield of 50.21% of the total activity. The purified enzyme was a glycoprotein with an apparent molecular mass of 75 and 84.5 kDa as estimated by sodium dodecyl sulfate^polyacrylamide gel electrophoresis and gel filtration, respectively. The enzyme lost approximately 50% of the molecular mass after treatment with glycosidases. The major end products of starch, amylose, amylopectin, pullulan and glycogen were maltose and maltotriose. The K m value for the pure enzyme was 0.056 mg ml 31 with soluble starch as the substrate. Enzyme activity was optimal at pH 5.5 and 50 ‡C. The enzyme retained 90% of the activity after incubation at 50 ‡C for 60 min and was inhibited by Cu 2þ , Fe 2þ and Hg 2þ .
Ermanin: An insect deterrent flavonoid from Passiflora foetida resin
Phytochemistry, 1991
... Permissions &amp;amp;amp; Reprints. Ermanin: An insect deterrent flavonoid from Passiflor... more ... Permissions &amp;amp;amp; Reprints. Ermanin: An insect deterrent flavonoid from Passiflora foetida resin. Fernando Echeverri Corresponding Author Contact Information , a , Gloria Cardona a , FernandoTorres a , Carlos Pelaez a , Winston Quiñones a and Enrique Renteria a. ...
European Journal of Operational Research, 2008
This paper presents a genetic algorithm for the Resource Constrained Multi-Project Scheduling Pro... more This paper presents a genetic algorithm for the Resource Constrained Multi-Project Scheduling Problem (RCMPSP). The chromosome representation of the problem is based on random keys. The schedules are constructed using a heuristic that builds parameterized active schedules based on priorities, delay times, and release dates defined by the genetic algorithm. The approach is tested on a set of randomly generated problems. The computational results validate the effectiveness of the proposed algorithm.
European Journal of Operational Research, 2005
This paper presents a hybrid genetic algorithm for the Job Shop Scheduling problem. The chromosom... more This paper presents a hybrid genetic algorithm for the Job Shop Scheduling problem. The chromosome representation of the problem is based on random keys. The schedules are constructed using a priority rule in which the priorities are defined by the genetic algorithm. Schedules are constructed using a procedure that generates parameterized active schedules. After a schedule is obtained a local search heuristic is applied to improve the solution. The approach is tested on a set of standard instances taken from the literature and compared with other approaches. The computation results validate the effectiveness of the proposed algorithm.
Ecotoxicology and Environmental Safety, 2004
The investigation on microcystin topics is increasing due to the related ecological and public he... more The investigation on microcystin topics is increasing due to the related ecological and public health risks. Recent investigation confirms a gap in establishing global patterns relating a particular environment to the bloom occurrence of a species and the production of certain microcystin variants. All the results concerning the environmental effects on the microcystin synthesis of one species must be checked in the light of genome diversity. Thus, the poisoning risks of a bloom depend on the strain causing toxicity. To be more effective, specific water treatment methods are required for blooms of different microcystin producing species (such as colonial and filamentous cyanobacteria found in stratified and unstratified water bodies, respectively). With the increasing number of new microcystin variants discovered, the development of new rapid, inexpensive and sensitive enough monitoring methods to promptly screen simultaneously a great diversity of toxins and also check their toxic effects is becoming necessary. r 2004 Elsevier Inc. All rights reserved.
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Papers by Fernando Gonçalves