Predictive factors of in-hospital mortality and of severe perioperative complications in myocardial revascularization surgery

OBJECTIVE: To investigate preoperative predictive factors of severe perioperative intercurrent events and in-hospital mortality in coronary artery bypass graft (CABG) surgery and to develop specific models of risk prediction for these events, mainly those that can undergo changes in the preoperative period. METHODS: We prospectively studied 453 patients who had undergone CABG. Factors independently associated with the events of interest were determined with multiple logistic regression and Cox proportional hazards regression model. RESULTS: The mortality rate was 11.3% (51/453), and 21.2% of the patients had 1 or more perioperative intercurrent events. In the final model, the following variables remained associated with the risk of intercurrent events: age ³ 70 years, female sex, hospitalization via SUS (Sistema Único de Saúde - the Brazilian public health system), cardiogenic shock, ischemia, and dependence on dialysis. Using multiple logistic regression for in-hospital mortality, the following variables participated in the model of risk prediction: age ³ 70 years, female sex, hospitalization via SUS, diabetes, renal dysfunction, and cardiogenic shock. According to the Cox regression model for death within the 7 days following surgery, the following variables remained associated with mortality: age ³ 70 years, female sex, cardiogenic shock, and hospitalization via SUS. CONCLUSION: The aspects linked to the structure of the Brazilian health system, such as factors of great impact on the results obtained, indicate that the events investigated also depend on factors that do not relate to the patient's intrinsic condition.

A new proposal to guide velocity and inclination in the ramp protocol for the treadmill ergometer

OBJECTIVE: To suggest criteria to guide protocol prescription in ramp treadmill testing, according to sex and age, based on velocity, inclination, and max VO2 reached by the population studied. METHODS: Prospective study describing heart rate (HR), time, velocity, inclination, and VO2 estimated at maximum effort of 1840 individuals from 4 to 79 years old, who performed a treadmill test (TT) according to the ramp protocol. A paired Student t test was used to assess the difference between predicted and reached max VO2, calculated according to the formulas of the "American College of Sports Medicine". RESULTS: Submaximal HR was surpassed in 90.1% of the examinations, with a mean time of 10.0±2.0 minute. Initial and peak inclination velocity of the exercise and max VO2 were inversely proportional to age and were greater in male patients. Predicted Max VO2 was significantly lower than that reached in all patients, except for female children and adolescents (age < 20 years old). CONCLUSION: Use of velocity, inclination, and maximum VO2 actually reached, as a criterion in prescribing the ramp protocol may help in the performance of exercise in treadmill testing. The ramp protocol was well accepted in all age groups and sexes with exercise time within the programmed 8 to 12 minutes.

Validation of the Killip-Kimball Classification and Late Mortality after Acute Myocardial Infarction

Background: The classification or index of heart failure severity in patients with acute myocardial infarction (AMI) was proposed by Killip and Kimball aiming at assessing the risk of in-hospital death and the potential benefit of specific management of care provided in Coronary Care Units (CCU) during the decade of 60. Objective: To validate the risk stratification of Killip classification in the long-term mortality and compare the prognostic value in patients with non-ST-segment elevation MI (NSTEMI) relative to patients with ST-segment elevation MI (STEMI), in the era of reperfusion and modern antithrombotic therapies. Methods: We evaluated 1906 patients with documented AMI and admitted to the CCU, from 1995 to 2011, with a mean follow-up of 05 years to assess total mortality. Kaplan-Meier (KM) curves were developed for comparison between survival distributions according to Killip class and NSTEMI versus STEMI. Cox proportional regression models were developed to determine the independent association between Killip class and mortality, with sensitivity analyses based on type of AMI. Results: The proportions of deaths and the KM survival distributions were significantly different across Killip class >1 (p <0.001) and with a similar pattern between patients with NSTEMI and STEMI. Cox models identified the Killip classification as a significant, sustained, consistent predictor and independent of relevant covariables (Wald χ2 16.5 [p = 0.001], NSTEMI) and (Wald χ2 11.9 [p = 0.008], STEMI). Conclusion: The Killip and Kimball classification performs relevant prognostic role in mortality at mean follow-up of 05 years post-AMI, with a similar pattern between NSTEMI and STEMI patients.

Value of the Qrs-T Angle in Predicting the Induction of Ventricular Tachyarrhythmias in Patients with Chagas Disease

Background:The QRS-T angle correlates with prognosis in patients with heart failure and coronary artery disease, reflected by an increase in mortality proportional to an increase in the difference between the axes of the QRS complex and T wave in the frontal plane. The value of this correlation in patients with Chagas heart disease is currently unknown.Objective:Determine the correlation of the QRS-T angle and the risk of induction of ventricular tachycardia / ventricular fibrillation (VT / VF) during electrophysiological study (EPS) in patients with Chagas disease.Methods:Case-control study at a tertiary center. Patients without induction of VT / VF on EPS were used as controls. The QRS-T angle was categorized as normal (0-105º), borderline (105-135º) or abnormal (135-180º). Differences between groups for continuous variables were analyzed with the t test or Mann-Whitney test, and for categorical variables with Fisher's exact test. P values < 0.05 were considered significant.Results:Of 116 patients undergoing EPS, 37.9% were excluded due to incomplete information / inactive records or due to the impossibility to correctly calculate the QRS-T angle (presence of left bundle branch block and atrial fibrillation). Of 72 patients included in the study, 31 induced VT / VF on EPS. Of these, the QRS-T angle was normal in 41.9%, borderline in 12.9% and abnormal in 45.2%. Among patients without induction of VT / VF on EPS, the QRS-T angle was normal in 63.4%, borderline in 14.6% and abnormal in 17.1% (p = 0.04). When compared with patients with normal QRS-T angle, those with abnormal angle had a fourfold higher risk of inducing ventricular tachycardia / ventricular fibrillation on EPS [odds ratio (OR) 4; confidence interval (CI) 1.298-12.325; p = 0.028]. After adjustment for other variables such as age, ejection fraction (EF) and QRS size, there was a trend for the abnormal QRS-T angle to identify patients with increased risk of inducing VT / VF during EPS (OR 3.95; CI 0.99-15.82; p = 0.052). The EF also emerged as a predictor of induction of VT / VF: for each point increase in EF, there was a 4% reduction in the rate of sustained ventricular arrhythmia on EPS.Conclusions:Changes in the QRS-T angle and decreases in EF were associated with an increased risk of induction of VT / VF on EPS.

Failure rates modelling for heterogenous populations

Mixture of distributions, decreasing failure rate, increasing failure rate, proportional hazards model, accelerated life model, asymptotic behavior of mixture failure rate

Cardiac Surgery Costs According to the Preoperative Risk in the Brazilian Public Health System

AbstractBackground:Heart surgery has developed with increasing patient complexity.Objective:To assess the use of resources and real costs stratified by risk factors of patients submitted to surgical cardiac procedures and to compare them with the values reimbursed by the Brazilian Unified Health System (SUS).Method:All cardiac surgery procedures performed between January and July 2013 in a tertiary referral center were analyzed. Demographic and clinical data allowed the calculation of the value reimbursed by the Brazilian SUS. Patients were stratified as low, intermediate and high-risk categories according to the EuroSCORE. Clinical outcomes, use of resources and costs (real costs versus SUS) were compared between established risk groups.Results:Postoperative mortality rates of low, intermediate and high-risk EuroSCORE risk strata showed a significant linear positive correlation (EuroSCORE: 3.8%, 10%, and 25%; p < 0.0001), as well as occurrence of any postoperative complication EuroSCORE: 13.7%, 20.7%, and 30.8%, respectively; p = 0.006). Accordingly, length-of-stay increased from 20.9 days to 24.8 and 29.2 days (p < 0.001). The real cost was parallel to increased resource use according to EuroSCORE risk strata (R$ 27.116,00 ± R$ 13.928,00 versus R$ 34.854,00 ± R$ 27.814,00 versus R$ 43.234,00 ± R$ 26.009,00, respectively; p < 0.001). SUS reimbursement also increased (R$ 14.306,00 ± R$ 4.571,00 versus R$ 16.217,00 ± R$ 7.298,00 versus R$ 19.548,00 ± R$935,00; p < 0.001). However, as the EuroSCORE increased, there was significant difference (p < 0.0001) between the real cost increasing slope and the SUS reimbursement elevation per EuroSCORE risk strata.Conclusion:Higher EuroSCORE was related to higher postoperative mortality, complications, length of stay, and costs. Although SUS reimbursement increased according to risk, it was not proportional to real costs.

Reduced Progression of Cardiac Allograft Vasculopathy with Routine Use of Induction Therapy with Basiliximab

AbstractIntroduction:Cardiac allograft vasculopathy (CAV) is a major limitation for long-term survival of patients undergoing heart transplantation (HT). Some immunosuppressants can reduce the risk of CAV.Objectives:The primary objective was to evaluate the variation in the volumetric growth of the intimal layer measured by intracoronary ultrasound (IVUS) after 1 year in patients who received basiliximab compared with that in a control group.Methods:Thirteen patients treated at a single center between 2007 and 2009 were analyzed retrospectively. Evaluations were performed with IVUS, measuring the volume of a coronary segment within the first 30 days and 1 year after HT. Vasculopathy was characterized by the volume of the intima of the vessel.Results:Thirteen patients included (7 in the basiliximab group and 6 in the control group). On IVUS assessment, the control group was found to have greater vessel volume (120–185.43 mm3 vs. 127.77–131.32 mm3; p = 0.051). Intimal layer growth (i.e., CAV) was also higher in the control group (27.30–49.15 mm3 [∆80%] vs. 20.23–26.69 mm3[∆33%]; p = 0.015). Univariate regression analysis revealed that plaque volume and prior atherosclerosis of the donor were not related to intima growth (r = 0.15, p = 0.96), whereas positive remodeling was directly proportional to the volumetric growth of the intima (r = 0.85, p < 0.001).Conclusion:Routine induction therapy with basiliximab was associated with reduced growth of the intima of the vessel during the first year after HT.

Mortality from Circulatory System Diseases and Malformations in Children in the State of Rio de Janeiro

Abstract Background: The epidemiological profile of mortality in a population is important for the institution of measures to improve health care and reduce mortality Objective: To estimate mortality rates and the proportional mortality from cardiovascular diseases and malformations of the circulatory system in children and adolescents. Methods: This is a descriptive study of mortality from cardiovascular diseases, malformations of the circulatory system, from all causes, ill-defined causes and external causes in children and adolescents in the state of Rio de Janeiro from 1996 to 2012. Populations were obtained from the Brazilian Institute of Geography and Statistics (Instituto Brasileiro de Geografia e Estatística - IBGE) and deaths obtained from the Department of Informatics of the Unified Health System (DATASUS)/Ministry of Health. Results: There were 115,728 deaths from all causes, 69,757 in males. The annual mortality from cardiovascular diseases was 2.7/100,000 in men and 2.6/100,000 in women. The annual mortality from malformations of the circulatory system was 7.5/100,000 in men and 6.6/100,000 in women. Among the specific causes of circulatory diseases, cardiomyopathies had the highest rates of annual proportional mortality, and from malformations of the circulatory system, it occurred due to unspecified malformations of the circulatory system, at all ages and in both genders. Conclusion: Mortality from malformations of the circulatory system was most striking in the first years of life, while cardiovascular diseases were more relevant in adolescents. Low access to prenatal diagnosis or at birth probably prevented the proper treatment of malformations of the circulatory system.

A influência dos pigmentos amarelo-laranja da semente de milho na coloração da gema de ovo de galinha

The effect of carotenoid pigments on the egg yolk color was studied in this paper. Three types of maize of known genetical constitution were used: Cateto, with deep orange endosperm; Armour, with yellow-orange endosperm and Cristal, with white endosperm. The carotenoid pigments of the two colored maizes were analysed: the total and both the active parts in relation to vitamin A and the zeaxanthin part showed to be practically double in the deep orange corn. The color of the yolk was orange when the ration had the deep orange corn and yellow in the case of the yellow-orange corn. The increase in shade was proportional to the amount of pigment present in the grains. If green feeds is added to the ration with white corn, the yolk becomes yellow or orange, depending on the amount of green given to the chickens. The practical importance of controlling the color of the yolk was emphasized.

Envelhecimento das aguardentes

1 - Colour, by itself, does not constitute a solid ground for judging of the age of a brandy because the more or less pronounced colour it acquires through aging can also be obtained by the addition of oack essence to newly distilled brandy. 2 - Urder the same conditions, colour intensity of a brandy wiU depend upon the nature of the wood and the condition of the storage. 3 - In accordance with the experimental results obtained by the present writers it rests no doubt that fermentation facility ferment resistence, produce and quality of the brendy all are factors depending upon the variety of the sugar cane. In addition, the authors presume that the variety of sugar cane has also influence upon the alteration of composition of the brandy submitted to aging. 4 - All aging phenomena of the brandy are accompanied by volume decreasing, what happens in a slow and continuous manner depending upon storage and environment conditions 5 - During brandy aging the alcoholic degree is greatly af- fected by evaporation, increasing or decreasing in accordance to the hygrometric state of the air and the teriperature in the place where the tuns are stored. 6 - The specific weight of the brandy is inversely proportio- nal to its alcoholic degree, but directly proportional to the extracts since the latter indicates the amount of dissolved residues. 7 - Brandy which shows high specific weight together with high alcoholic degree cannot be considered as aged. It may, however, be takens for brandy artificially coloved in order to conceal its actual age. 8 - The amount of extracts increases with aging, since it is the result of the solvent action of the brandy upon the soluble extractive substances of the wood. Notwithstanding that the extract, considered alone, has no value in determining the age of a brandy, since nothing easier is ohan to nake it change artificially. 9 -During aging the brandy get acidity in physiological as well as in physical way, but never by the action of microorganisms. 10 - The estturs produced during aging by the action of acids upon alcohols are the mean factors of the savour (bouquet) of a brandy and therefore every thing shall be done tor fhr estherification of a preserved brandy being not limited. 11 - Aeration increases esther formation, reduces the aging- time and turn better the taste qualities of the brandy. 12 - Due to the great proportion of high alcohols ordinarily found in the brandy, their analytical discrimination will be greatly important. 13 - The high alcohols are not responsable for the disastrous consequences of the alcoholism, but the high percentage of uthyl alcohol present in the brandy. 14 - The aldehydes appear always in high rate in the brazilian brandys in consequence of some intermediary products of the oxydation of the alcohols being left in the brandys during aging. 15 - The age has little or no influence on the quantity of phurphurol present in a brandy whose amount varies greatly the manner in which the wines to be distilled are treated. Wines centrifugalized or filtered before distillation always give rise to brandys poorer in phurphurol as compared with those distilled without these treatments. 16 - Though greatly variable, brandys of good qualities generally show a high residues coefficient, never under 200 mmg 17 - Lusson - Rocques oxydation coefficient cannot be indis- criminately applied to any brandy class, being, on the contrary, specifically destined to cognacs.

Selbstparametrierende Steuerung für den Guss von Sanitärkeramik

In der Firma KERAMAG wird für den Guss von Sanitärkeramik das Hohlgussverfahren angewendet. Bei diesem Gießverfahren treten Fehlerbilder auf, die die Qualität negativ beeinflussen. Ziel der vorliegenden Arbeit ist den Gießprozess zu optimieren, damit sich die komplexen physikalischen Eigenschaften des Schlickers weniger stark auf den technologischen Ablauf des Gießprozesses auswirken. Dazu wird eine intelligente Softwarelösung (automatische Eingießsteuerung)erarbeitet, die die herkömmliche elektromechanische Steuerung ablöst. Als erstes werden der Aufbau und die Funktionsweise der herkömmlichen Gießanlage analysiertund die Einflüsse auf den technologischen Ablauf des Gießprozess untersucht. Aus dengewonnenen Erkenntnissen der Analyse werden Lösungsansätze zur Optimierung desGießprozesses abgeleitet. Mit den Anforderungen die sich aus den Lösungsansätzen ergebenen, wird eine geeigneteHardware für die Steuerungskomponenten des Automatisierungssytems ausgewählt. Auf Grundlage der ermittelten Steuerungsaufgaben wird mit SIMATIC-STEP7 ein Automatisierungsprojekt erstellt. Dabei sind die behandelten Schwerpunkte die „Selbstparametrierung und Optimierung der Eingießkurve“ und die „gleitende Skalierung der Analogausgangsgröße des Proportional-Druckregelventils“. Die vorgeschlagenen Lösungen werden an einer Gießanlage installiert und es wird der Nachweis erbracht, dass die Aufgabenstellung vollständig umgesetzt werden konnte.

Alterações cutâneas do cão no Kala-Azar sul-americano

According to E. Chagas (1938), South-American Kala Azar is a widespread disease from the jungle, several cases being reported from North Brazil (Estado do Pará: Marajó Island, Tocantins and Gurupi river valleys; Estados do Piauí and Ceará: coast and hinterland). Other cases were found in Northeast Brazil (Estados de Pernambuco, Alagôas and Sergipe: coast and hinterland; Estado da Bahia: hinterland). A few cases were described from Estado de Mato-Grosso (Brazil), Provincia de Salta and Território do Chaco (Argentine), and Zona contestada do Chaco (Paraguai-Bolívia). A well defined secondary anemia associated with enlargement of the liver and spleen are the chief symptoms. Death usually occurs in cachexia and with symptoms of heart failure. Half the patients were children aged less than ten years (CHAGAS, CASTRO & FERREIRA, 1937). Quite exhaustive epidemiological researches performed by CHAGAS, FERREIRA, DEANE, DEANE & GUIMARÃES (1938) in Municipio de Abaeté (Estado do Pará, Brazil) gave the incidence of 1.48% for the natural infection in human, 4.49% in dogs, and 2.63% in cats. The infection was arcribed (CUNHA & CHAGAS, 1937) to a new species of Leishmania (L. chagasi). Latter CUNHA (1938) state, that it is identical to L. infantum. ADLER (1940) found that so far it has been impossible to distinguish L. chagasi from L. infantum by any laboratory test but a final judgment must be reserved until further experiments with different species of sandflies have been carried out. Skin changes in canine Kala Azar were signaled by many workers, and their importance as regards the transmission of the disease is recognized by some of them (ADLER & THEODOR, 1931, 2. CUNHA, 1933). Cutaneous ulcers in naturally infected dogs are referred by CRITIEN (1911) in Malta, by CHODUKIN & SCHEVTSCHENKO (1928) in Taschkent, by DONATIEN & LESTOCQUARD (1929) and by LESTOCQUARD & PARROT (1929) in Algeria, and by BLANC & CAMINOPETROS (1931) in Greece. Depilation is signaled by YAKIMOFF & KOHL-YAKIMOFF (1911) in Tunis, by YAKIMOFF (1915) in Turkestan. Eczematous areas or a condition described as "eczema furfurace" is sometimes noted in the areas of depilation (DONATIEN & LESTOCQUARD). The skin changes noticed by ADLER & THEODOR (1932) in dogs naturally infected with Mediterranean Kala Azar can be briefly summarized as a selective infiltration of macrophages around hair follicles including the sebaceous glands and the presence of infected macrophages in normal dermis. The latter phenomenon in the complete absence of secondary infiltration of round cells and plasma cells is the most striking characteristic of canine Kala Azar and differentiates it from L. tropica. In the more advanced stages the dermis is more cellular than that of normal dogs and may even contain a few small dense areas of infiltration with macrophages and some round cells and polymorphs. The external changes, i. e., seborrhea and depilation are roughly proportional to the number of affected hair follicles. In dogs experimentally infected with South-American Kala Azar the parasites were regularly found in blocks of skin removed from the living animal every fortnight (CUNHA, 1938). The changes noticed by CUNHA, besides the presence of Leishmania, were perivascular and diffuse infiltration of the cutis with mononuclears sometimes more marked near hair follicles, as well as depilation, seborrhea and ulceration. The parasites were first discovered and very numerous in the paws. Our material was obtained from dogs experimentally infected by Dr. A. MARQUES DA CUNHA< and they were the subject of a previous paper by CUNHA (1938). In this study, however, several animals were discarded as it was found that they did develop a superimposed infection by Demodex canis. This paper deals with the changes found in 88 blocks of skin removed from five dogs, two infected with two different canine strains, and three with two distinct human strains of South-American Kala Azar. CUNHA'S valuable material affords serial observations of the cutaneous changes in Kala Azar as most of the blocks of skin were taken every fortnight. The following conclusions were drawn after a careful microscopic study. (1) Skin changes directly induced in the dog by the parasites of South-American Kala Azar may b described as an infiltration of the corium (pars papillaris and upper portion of the reticular layer) by histocytes. Parasites are scanty, at first, latter becoming very numerous in the cytoplasm of such cells. Sometimes the histocytes either embedding or not leishman bodies appear as distinct nodes of infiltration or cell aggregations (histocytic granuloma, Figs. 8 and 22) having a perivascular distribution. The capillary loops in the papillae, the vessels of the sweat glands, the subpapillary plexus, the vertical twigs connecting the superficial and deep plexuses are the ordinary seats of the histocytic Kala Azar granulomata. (2) Some of the cutaneous changes are transient, and show spontaneous tendency to heal. A gradual transformation of the histocytes either containing or not leishman bodies into fixed connective tissue cells or fibroblasts occut and accounts for the natural regression just mentioned. Figs. 3, 5, 18, 19 and 20 are good illustrations of such fibroblastic transformation of the histocytic Kala Azar granulomata. (3) Skin changes induced by the causative organism of South-American Kala Azar are neither uniform nor simultaneous. The same stage may be found in the same dog in different periods of the disease, and not the same changes take place when pieces from several regions are examined in the same moment. The fibroblastic transformation of the histocytic granulomata marking the beginning of the process of repair, e. g., was recognised in dog C, in the 196th as well as in the 213rd (Fig. 18) and 231st (Fig. 19) days after the inoculation. (4) The connective tissue of the skin in dogs experimentally infected with South-American Kala Azar is overflowed by blood cells (monocytes and lymphocytes) besides the proliferation in situ of undifferentiated mesenchymal cells. A marked increase in the number of cells specially the "ruhende Wanderzellen" (Figs. 4 and 15) is noticed even during the first weeks after inoculation (prodomal stage) when no leishman bodies are yet found in the skin. Latter a massive infiltration by amoeboid wandering cells similar to typical blood monocytes (Fig. 21) associated to a small number of lymphocytes and plasma cells (Figs. 9, 17, 21, and 24) indicates that the emigration of blood cells...

Os anofelinos do sub-gênero kerteszia em relação à distribuição das bromeliáceas em comunidades florestais do município de Brusque, Estado de Santa Catarina

The present work is part of the studies realized under the authority of the National Service of Malaria (Brazil), with the collaboration of scientists of the Oswaldo Cruz Institute, in some forests of the southern part of Brazil.This is the first of a series and its subject is the development of the Anopheles mosquitoes of the kerteszia in water collected in Bromeliaceae leaves. The ecology of Bromeliaceae was studied in a previous work. The botanical material was classified by specialists from several botanical institutions from Europe and the United States of America. The most important ecological relations of the “bromeliad-kerteszia” problem were presented through four indices: 1st Positivity index – Relative frequency of bromeliad with watery forms in the bromeliad examined. 2nd Larval index – Mean number of watery forms in the positive bromeliad. 3rd Ovoposition index – Product of the Positivy index by the Larval index. 4th MK index – Product of the Ovoposition index by the total number of bromeliad, positive or not, in a unity of area (1.000 m²). The capture of flying forms in relation to the relative humidity was also studied. From the several forests of the Brusque region we have selected one community of each type, which were the most representative forests in Southern Brazil. Conclusions on the “bromeliad-kerteszia” problem – From a general point of view only a few factors are really important and these are listed below: 1°) The volum of water on the bromeliad. 2°) The level where the bromeliad is fixed. 3°) The number of bromeliad in unity of area. The distribution of microclimas in the forest through the considered levels has a direct influence on the species of subgenus Kerteszia (qualitative influence) and an indirect influence through the ecological distribution of the more frequent bromeliad with best qualities as biotope for the watery forms (qualitative influence). The MK index is roughly proportional to the square of half the total number of Bromeliaceae in a certain type of forest. Then the MK index would be a certain function of the ecological type of the forest and of the total number of bromeliad in a unity of area. MK approximately α x (x/10)² . x = n° of bromeliad in a unity of área (1.000 m²); α = qualitative factor. It would be interesting to see if this proportion is maintained when we have examined a greater number of forests of different types.

Characterisation of neutron spectra in mixed high energy fields in lineal accelerators: response functions validation

Actualment, la resposta de la majoria d’instrumentació operacional i dels dosímetres personals utilitzats en radioprotecció per a la dosimetria neutrònica és altament dependent de l’energia dels espectres neutrònics a analitzar, especialment amb camps neutrònics amb una important component intermitja. En conseqüència, la interpretació de les lectures d’aquests aparells es complicada si no es té un coneixement previ de la distribució espectral de la fluència neutrònica en els punts d’interès. El Grup de Física de les Radiacions de la Universitat Autònoma de Barcelona (GFR-UAB) ha desenvolupat en els últims anys un espectròmetre de neutrons basat en un Sistema d’Esferes Bonner (BSS) amb un contador proporcional d’3He com a detector actiu. Els principals avantatges dels espectròmetres de neutrons per BSS són: la seva resposta isotròpica, la possibilitat de discriminar la component neutrònica de la gamma en camps mixtos, i la seva alta sensibilitat neutrònica als nivells de dosi analitzats. Amb aquestes característiques, els espectròmetres neutrònics per BSS compleixen amb els estándards de les últimes recomanacions de la ICRP i poden ser utilitzats també en el camp de la dosimetria neutrònica per a la mesura de dosis en el rang d’energia que va dels tèrmics fins als 20 MeV, en nou ordres de magnitud. En el marc de la col•laboració entre el GFR - UAB i el Laboratorio Nazionale di Frascati – Istituto Nazionale di Fisica Nucleare (LNF-INFN), ha tingut lloc una experiència comparativa d’espectrometria per BSS amb els feixos quasi monoenergètics de 2.5 MeV i 14 MeV del Fast Neutron Generator de l’ENEA. En l’exercici s’ha determinat l’espectre neutrònic a diferents distàncies del blanc de l’accelerador, aprofitant el codi FRUIT recentment desenvolupat pel grup LNF. Els resultats obtinguts mostren una bona coherència entre els dos espectròmetres i les dades mesurades i simulades.

Features of reproduction in laboratory-reared Aedes fluviatilis (Lutz, 1904) (Diptera: Culicidae)

Observations were made on 100 female Aedes fluviatilis (Lutz) maintained individually from the first blood meal onwards and allowed one blood meal during each oviposition cycle, 5% dextrose solution been supplied throughout life. The average length of live was 49.9 ± 17.8 days; the logarithm of the mortality rate increased proportionately to physiological age. The insects took an average of 7.3 ± 3.2 blood meals and produced a mean of 7.9 ± 3.7 clutches of eggs. There was a progressive decrease, proportional to advancing physiological age, in the mean numbers of eggs laid in successive oviposition cycles, in the intervals between blood feeding oviposition, and in the numbers of larvae that hatched. Delayed oviposition, transient sterility and a total loss of fertility were also recorded.