1000 resultados para Agatha, Saint, -approximately 250


Relevância:

100.00% 100.00%

Publicador:

Resumo:

The present study analyzed metallothionein (MT) excretion from liver to bile in Nile Tilapia (Oreochromis niloticus) exposed to sub-lethal copper concentrations (2mgL(-1)) in a laboratory setting. MTs in liver and bile were quantified by spectrophotometry after thermal incubation and MT metal-binding profiles were characterized by size exclusion high performance liquid chromatography coupled to ICP-MS (SEC-HPLC-ICP-MS). Results show that liver MT is present in approximately 250-fold higher concentrations than bile MT in non-exposed fish. Differences between the MT profiles from the control and exposed group were observed for both matrices, indicating differential metal-binding behavior when comparing liver and bile MT. This is novel data regarding intra-organ MT comparisons, since differences between organs are usually present only with regard to quantification, not metal-binding behavior. Bile MT showed statistically significant differences between the control and exposed group, while the same did not occur with liver MT. This indicates that MTs synthesized in the liver accumulate more slowly than MTs excreted from liver to bile, since the same fish presented significantly higher MT levels in liver when compared to bile. We postulate that bile, although excreted in the intestine and partially reabsorbed by the same returning to the liver, may also release MT-bound metals more rapidly and efficiently, which may indicate an efficient detoxification route. Thus, we propose that the analysis of bile MTs to observe recent metal exposure may be more adequate than the analysis of liver MTs, since organism responses to metals are more quickly observed in bile, although further studies are necessary.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Includes bibliographical references.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Stalker (AIAA Paper 87-0403) has suggested that, by ejecting molecules directly upstream from the entire face of a satellite, it is possible to reduce the drag on a satellite in low-Earth orbit and hence maintain orbit with a total fuel mass (for forward ejection and conventional reaction rockets) less than the typical mass requirements of conventional rockets. An analytical analysis is presented here, as well as Monte Carlo simulations. These indicate that to reduce the overall drag on the satellite significantly, collisions between the freestream and ejected molecules must occur at least two satellite diameters upstream. This can be achieved if the molecules are ejected far upstream from the satellite’s surface through a sting that projects forward from the satellite. Using some estimates of what would be feasible sting arrangements, we find that the drag on the satellite can be reduced to such an extent that the satellite’s orbit can be maintained with a total fuel mass of less than 60% of that required for reaction rockets alone. Upstream ejection is effective in reducing the drag for freestream Knudsen numbers less than approximately 250, but not otherwise.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

1. Chrysophtharta bimaculata is a native chrysomelid species that can cause chronic defoliation of plantation and regrowth Eucalyptus forests in Tasmania, Australia. Knowledge of the dispersion pattern of C. bimaculata was needed in order to assess the efficiency of an integrated pest management (IPM) programme currently used for its control. 2. Using data from yellow flight traps, local populations of C. bimaculata adults were monitored over a season at spatial scales relevant to commercial forestry: within a 50-ha operational management unit (a forestry 'coupe') and between coupes. In addition, oviposition was monitored over a season at a subset of the between-coupe sites. 3. Dispersion indices (Taylor's Power Law and Iwao's Mean Crowding regression method) demonstrated that C. bimaculata adults were spatially aggregated within and between coupes, although the number of egg-batches laid at the between-coupe scale was uniform. Spatial autocorrelation analysis showed that trap-catches at the within-coupe level were similar (positively autocorrelated) to a radius distance of approximately 110 m, and then dissimilar (negatively autocorrelated) at approximately 250 m. At the between-coupe scale, no repeatable spatial autocorrelation patterns were observed. 4. For any individual site, rapid changes in beetle density were observed to be associated with loosely aggregated flights of beetles into and out of that site. Peak adult catches (> the weekly mean plus standard deviation trap-catch) for a site occurred for a period of 2.0 +/- 0.22 weeks at a time (n = 37), with normally only one or two peaks per site per season. Peak oviposition events for a site occurred on average 1.4 +/- 0.11 times per season and lasted 1.5 +/- 0.12 weeks. 5. Analysis of an extensive data set (n = 417) demonstrated that adult abundance at a site was positively correlated with egg density, but negatively correlated with tree damage (caused by conspecifics) and the presence of conspecific larvae. There was no relationship between adult abundance and a visual estimate of the amount of young foliage on trees. 6. Adults of C. bimaculata are show n to occur in relatively small, mobile aggregations. This means that pest surveys must be both regular (less than 2 weeks apart) and intensive (with sampling points no more than 150 m apart) if beetle populations are to be monitored with confidence. Further refinement of the current IPM strategy must recognize the problems posed by this temporal and spatial patchiness, particularly with regard to the use of biological insecticides, such as Bacillus thuringiensis, for which only a very short operational window exists.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

1 This study has administered pirfenidone (5-methyl-l-phenyl-2-[1H]-pyridone) or amiloride to attenuate the remodelling and associated functional changes, especially an increased cardiac stiffness, in DOCA-salt hypertensive rats. 2 In control rats, the elimination half-life of pirfenidone following a single intravenous dose of 200 mg kg(-1) was 37 min while oral bioavailability at this dose was 25.7%. Plasma pirfenidone concentrations in control rats averaged 1.9 +/- 0.1 mug ml(-1) over 24 It after 14 days' administration as a 0.4% mixture in food. 3 Pirfenidone (approximately 250-300 mg kg(-1) day(-1) as 0.4% in food) and amiloride (I mg kg-1 day(-1) sc) were administered for 2 weeks starting 2 weeks post-surgery. Pirfenidone but not amiloride attenuated ventricular hypertrophy (2.69 +/- 0.09, UNX 2.01 +/- 0.05. DOCA-salt 3.11 +/- 0.09 mg kg(-1) body wt) without lowering systolic blood pressure. 4 Collagen deposition was significantly increased in the interstitium after 2 weeks and further increased with scarring of the left ventricle after 4 weeks; pirfenidone and amiloride reversed the increases and prevented further increases. This accumulation of collagen was accompanied by an increase in diastolic stiffness constant; both amiloride and pirfenidone, reversed this increase. 5 Noradrenaline potency (positive chronotropy) was decreased in right atria (neg log EC50: control 6.92 +/- 0.06; DOCA-salt 6.64 +/- 0.08); pirfenidone but not amiloride reversed this change. Noradrenaline was a more potent vasoconstrictor in thoracic aortic rings (neg log EC50: control 6.91 +/- 0.10; DOCA-salt 7.90 +/- 0.07); pirfenidone treatment did not change noradrenaline potency. 6 Thus, pirfenidone and amiloride reverse and prevent cardiac remodelling and the increased cardiac stiffness without reversing the increased vascular responses to noradrenaline.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Mestrado em Energias Sustentáveis

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Background:Diabetes affects approximately 250 million people in the world. Cardiovascular autonomic neuropathy is a common complication of diabetes that leads to severe postural hypotension, exercise intolerance, and increased incidence of silent myocardial infarction.Objective:To determine the variability of heart rate (HR) and systolic blood pressure (SBP) in recently diagnosed diabetic patients.Methods:The study included 30 patients with a diagnosis of type 2 diabetes of less than 2 years and 30 healthy controls. We used a Finapres® device to measure during five minutes beat-to-beat HR and blood pressure in three experimental conditions: supine position, standing position, and rhythmic breathing at 0.1 Hz. The results were analyzed in the time and frequency domains.Results:In the HR analysis, statistically significant differences were found in the time domain, specifically on short-term values such as standard deviation of NN intervals (SDNN), root mean square of successive differences (RMSSD), and number of pairs of successive NNs that differ by more than 50 ms (pNN50). In the BP analysis, there were no significant differences, but there was a sympathetic dominance in all three conditions. The baroreflex sensitivity (BRS) decreased in patients with early diabetes compared with healthy subjects during the standing maneuver.Conclusions:There is a decrease in HR variability in patients with early type 2 diabetes. No changes were observed in the BP analysis in the supine position, but there were changes in BRS with the standing maneuver, probably due to sympathetic hyperactivity.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Because we live in an extremely complex social environment, people require the ability to memorize hundreds or thousands of social stimuli. The aim of this study was to investigate the effect of multiple repetitions on the processing of names and faces varying in terms of pre-experimental familiarity. We measured both behavioral and electrophysiological responses to self-, famous and unknown names and faces in three phases of the experiment (in every phase, each type of stimuli was repeated a pre-determined number of times). We found that the negative brain potential in posterior scalp sites observed approximately 170 ms after the stimulus onset (N170) was insensitive to pre-experimental familiarity but showed slight enhancement with each repetition. The negative wave in the inferior-temporal regions observed at approximately 250 ms (N250) was affected by both pre-experimental (famous>unknown) and intra-experimental familiarity (the more repetitions, the larger N250). In addition, N170 and N250 for names were larger in the left inferior-temporal region, whereas right-hemispheric or bilateral patterns of activity for faces were observed. The subsequent presentations of famous and unknown names and faces were also associated with higher amplitudes of the positive waveform in the central-parietal sites analyzed in the 320-900 ms time-window (P300). In contrast, P300 remained unchanged after the subsequent presentations of self-name and self-face. Moreover, the P300 for unknown faces grew more quickly than for unknown names. The latter suggests that the process of learning faces is more effective than learning names, possibly because faces carry more semantic information.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The diffusion of mobile telephony began in 1971 in Finland, when the first car phones, called ARP1 were taken to use. Technologies changed from ARP to NMT and later to GSM. The main application of the technology, however, was voice transfer. The birth of the Internet created an open public data network and easy access to other types of computer-based services over networks. Telephones had been used as modems, but the development of the cellular technologies enabled automatic access from mobile phones to Internet. Also other wireless technologies, for instance Wireless LANs, were also introduced. Telephony had developed from analog to digital in fixed networks and allowed easy integration of fixed and mobile networks. This development opened a completely new functionality to computers and mobile phones. It also initiated the merger of the information technology (IT) and telecommunication (TC) industries. Despite the arising opportunity for firms' new competition the applications based on the new functionality were rare. Furthermore, technology development combined with innovation can be disruptive to industries. This research focuses on the new technology's impact on competition in the ICT industry through understanding the strategic needs and alternative futures of the industry's customers. The change speed inthe ICT industry is high and therefore it was valuable to integrate the DynamicCapability view of the firm in this research. Dynamic capabilities are an application of the Resource-Based View (RBV) of the firm. As is stated in the literature, strategic positioning complements RBV. This theoretical framework leads theresearch to focus on three areas: customer strategic innovation and business model development, external future analysis, and process development combining these two. The theoretical contribution of the research is in the development of methodology integrating theories of the RBV, dynamic capabilities and strategic positioning. The research approach has been constructive due to the actual managerial problems initiating the study. The requirement for iterative and innovative progress in the research supported the chosen research approach. The study applies known methods in product development, for instance, innovation process in theGroup Decision Support Systems (GDSS) laboratory and Quality Function Deployment (QFD), and combines them with known strategy analysis tools like industry analysis and scenario method. As the main result, the thesis presents the strategic innovation process, where new business concepts are used to describe the alternative resource configurations and scenarios as alternative competitive environments, which can be a new way for firms to achieve competitive advantage in high-velocity markets. In addition to the strategic innovation process as a result, thestudy has also resulted in approximately 250 new innovations for the participating firms, reduced technology uncertainty and helped strategic infrastructural decisions in the firms, and produced a knowledge-bank including data from 43 ICT and 19 paper industry firms between the years 1999 - 2004. The methods presentedin this research are also applicable to other industries.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Tämän diplomityön tarkoituksena on selvittää eräällä pelkkahakkurilla tuotetun selluhakkeen laadun vaihtelua ja laadun hallinnan mahdollisuuksia. Tutkittu laite on Veisto Oy:n suunnittelema ja valmistama HewSaw R200 - pelkkahakkuri. Tutkimuksessa selvitetään sahauksen yhteydessä pelkkahakkurilla tuotettavaan selluhakkeeseen vaikuttavien parametrien: hakkurin pyörimisnopeuden, tukin syöttönopeuden, hakkurin terien vaihtovälin, selluhakkeen palakoon, tukkiluokan, puun lämpötilan ja puulajin välisiä korrelaatioita ja edellä mainittujen tekijöiden vaikutusta tuotettavan hakkeen palakokojakaumaan. Tämä palakokojakauma määrää selluhakkeen laadunmäärityksessä käytettävän, niin sanotun hintakertoimen. Kyseinen hintakerroin määritellään SCAN – CM 40 – standardin mukaisella seulonnalla. Tämä standardi on käytössä laadunmäärityksen perusteena kaikilla pohjoismaisilla sellutehtailla.Tutkimuksen kirjallisessa osuudessa esitellään sahateollisuuden merkittävimmät sahausmenetelmät ja sivuotteiden tuotanto . Seuraavassa osassa käsitellään erikseen selluhaketta sahateollisuuden sivutuotteena ja sen taloudellista merkitystä sahateollisuudessa. Jatkossa keskitytään selluhakkeen tuottamiseen pelkkahakkurilla ja puun työstämiseen liittyviin periaatteisiin.Tutkimuksen kokeellisessa osuudessa tutkittaan, eri sahalaitoksilta otettujen hakenäytteiden perusteella, tärkeimmiksi havaittujen tuotantoparametrien vaikutusta selluhakkeen laatuun ja saantoon. Näytteitä otettiin tutkimuksen kokeellisessa osuudessa yhteensä noin 250 kappaletta. Tutkimuksen tuloksia käsittelevässä osuudessa on annettu malli tutkitulla HewSaw R200 - pelkkahakkurilla tuotetun selluhakkeen laadun ja määrän arvioimiseen.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Intracerebral haemorrhage (ICH) is a spontaneous extravasation of blood into brain parenchyma. Although ICH represents approximately only 15% of all strokes, it is one of the major causes of stroke-related death and disability. One of the causes of poor outcome is the haematoma growth. The association between elevated blood pressure (BP) and haematoma enlargement in acute ICH has not been clarified. Our objective is to try to identify this relationship that may suggest an immediate target for intervention to possibly improve outcomes in patients with spontaneous ICH and might settle the controversy surrounding the optimal management of blood pressure.We propose a retrospective revision using a sample present in our database of approximately 250 patients with primary ICH and less than 12h from symptoms onset. Systolic blood pressure levels (SBP) are assessed at baseline, at 6h, at 12h, at 24h and at 72h, being these last four the average levels of the different recordings during those time intervals. Haematoma growth will be defined as an increase in the volume of intraparenchymal haemorrhage of >33% as measured by image analysis on the 24-hour CT or 72-hour CT compared with the baseline CT scan. A qualified neuroradiologist not informed of the aim of the study, will review the CT images. The secondary objective will be to correlate the BP levels in the acute phase of ICH with clinical outcome. We will evaluate early neurologic deterioration at 72h by using the National Institutes of Health Stroke Scale (NIHSS); outcome at 90 days by using the modified Rankin scale and mortality at 72h and 90 days. The statistical analysis will be adjusted by possibly confounding variables

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Lumbar hernia is defined as an abdominal passage through the posterior abdominal wall. Approximately 250 to 300 cases have been described in the literature, being quite infrequent. Untreated lumbar hernia may result in severe complications. The authors report a case of a 60 year old male patient presenting a large bowel obstruction and perfuration secundary to incarceration of descending colon within a lumbar hernia. This was diagnosed by clinical history and computed tomography. The patient was successfully treated surgically.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The aim of the present study was to evaluate the effect of Ginkgo biloba treatment (EGb 761, 200 mg kg-1 day-1) administered from day 0 to 20 of pregnancy on maternal reproductive performance and on the maternal and fetal liver antioxidant systems of streptozotocin-induced diabetic Wistar rats. On day 21 of pregnancy, the adult rats (weighing approximately 250 ± 50 g, minimum number = 13/group) were anesthetized to obtain maternal and fetal liver samples for superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and total glutathione (GSH-t) determinations. The uterus was weighed with its contents. The diabetic (G3) and treated diabetic (G4) groups of rats presented significant maternal hyperglycemia, reduced term pregnancy rate, impaired maternal reproductive outcome and fetal-placental development, decreased GSH-Px (G3 = G4 = 0.6 ± 0.2) and SOD (G3 = 223.0 ± 84.7; G4 = 146.1 ± 40.8), and decreased fetal CAT activity (G3 = 22.4 ± 10.6; G4 = 34.4 ± 14.1) and GSH-t (G3 = G4 = 0.3 ± 0.2), compared to the non-diabetic groups (G1, untreated control; G2, treated). For G1, maternal GSH-Px = 0.9 ± 0.2 and SOD = 274.1 ± 80.3; fetal CAT = 92.6 ± 82.7 and GSH-t = 0.6 ± 0.5. For G2, G. biloba treatment caused no toxicity and did not modify maternal or fetal-placental data. EGb 761 at the nontoxic dose used (200 mg kg-1 day-1), failed to modify the diabetes-associated increase in maternal glycemia, decrease in pregnancy rate, decrease in antioxidant enzymes, and impaired fetal development when the rats were treated throughout pregnancy (21 days).

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Fried foods are widely consumed in Brazil and their quality depends on the oil or fat they are fried. Qualitative (physical chemistry indices) and quantitative measurements (fry-life oil or fat until disposal, oil turnover, type of oil or fat and amount and type of fried foods) and associations were performed. We applied a structured form and collected 60 mL of frying oil or fat in each of the 70 fried food stands of 15 street-fairs in Goiânia, Brazil. All samples were suitable in the quantity of free fat acids (<0.9% oleic acid), one was inadequate to peroxide value (>10 mEq/kg) and 1/3 was unsuitable to polar compounds (<25%). The majority (62%) use temperature up to the allowed (180 ºC). Approximately 250 units of products are fried in at least one day in 42% of the fried food stands. Soybean oil is used in the majority (94%) of fried food stands and the fry-life is of 6 hours (60%) or a day of work/sale. The nonconformity of the content of total polar compounds in fried foods had significant association with frying time and the conformity of acidity had significant relationship with frying time by a chi-square test. All other associations were not significant. A fry-life of oil or fat up to 6 hours can avoid the excess of polar compounds in the frying medium and protect the quality of fred foods.