Experimental procedures for the identification of material properties of intervertebal disc - a contribution for the development of biomimetic substitutes for the nucleus pulposus

Tese de Doutoramento em Engenharia Mecânica.

Tratamento endovascular da persistência do canal arterial em adulto

A persistência do canal arterial (PCA) é uma anomalia relativamente freqüente e de simples correção. A correção envolve a ligadura do ducto com ou sem a sua secção. A anomalia em adultos pode provocar hipertensão pulmonar persistente e disfunção ventricular. A correção em adultos é controversa e de maior risco. Um caso de correção endovascular com acesso intra-abdominal da PCA em adulto é descrito.

Instruments for image guided procedures - IIGP : review summaries for minimal invasive and image guided technologies and clinical procedures : student review papers on selected topics

Michael Friebe, editor ; Otto-von-Guericke-Universität Magdeburg, Institut für Medizintechnik, Lehrstuhl Kathetertechnologie und bildgesteuerte Therapie (INKA - Intelligente Katheter), Forschungscampus STIMULATE (Solution Centre for Image Guided Local Therapies)

The Compleat cladist : a primer of phylogenetic procedures / E.O. Wiley [et al.]

no.19 (1991)

Eliciting and fostering learners' metacognitive knowledge about language learning in self-directed learning programs: a review of data collection methods and procedures

Són molts els estudis que avui en dia incideixen en la necessitat d’oferir un suport metodològic i psicològic als aprenents que treballen de manera autònoma. L’objectiu d’aquest suport és ajudar-los a desenvolupar les destreses que necessiten per dirigir el seu aprenentatge així com una actitud positiva i una major conscienciació envers aquest aprenentatge. En definitiva, aquests dos tipus de preparació es consideren essencials per ajudar els aprenents a esdevenir més autònoms i més eficients en el seu propi aprenentatge. Malgrat això, si bé és freqüent trobar estudis que exemplifiquen aplicacions del suport metodològic dins els seus programes, principalment en la formació d’estratègies o ajudant els aprenents a desenvolupar un pla de treball, aquest no és el cas quan es tracta de la seva preparació psicològica. Amb rares excepcions, trobem estudis que documentin com s’incideix en les actituds i en les creences dels aprenents, també coneguts com a coneixement metacognitiu (CM), en programes que fomenten l’autonomia en l’aprenentatge. Els objectius d’aquest treball son dos: a) oferir una revisió d’estudis que han utilitzat diferents mitjans per incidir en el CM dels aprenents i b) descriure les febleses i avantatges dels procediments i instruments que utilitzen, tal com han estat valorats en estudis de recerca, ja que ens permetrà establir criteris objectius sobre com i quan utilitzar-los en programes que fomentin l’aprenentatge autodirigit.

The role of central bank operating procedures in an economy with productive government spending

The choice of either the rate of monetary growth or the nominal interest rate as the instrument controlled by monetary authorities has both positive and normative implications for economic performance. We reexamine some of the issues related to the choice of the monetary policy instrument in a dynamic general equilibrium model exhibiting endogenous growth in which a fraction of productive government spending is financed by means of issuing currency. When we evaluate the performance of the two monetary instruments attending to the fluctuations of endogenous variables, we find that the inflation rate is less volatile under nominal interest rate targeting. Concerning the fluctuations of consumption and of the growth rate, both monetary policy instruments lead to statistically equivalent volatilities. Finally, we show that none of these two targeting procedures displays unambiguously higher welfare levels.

Fair procedures. Evidence from games involving lotteries

Procedural fairness plays a prominent role in the social discourse concerning the marketplace in particular, and social institutions in general. Random procedures are a simple case, and they have found application in several important social allocation decisions. We investigate random procedures in the laboratory. We find that an unbiased random procedure is an acceptable substitute for an unbiased allocation: similar patterns of acceptance and rejection result when either is inserted as a feasible proposal in a sequential battle-of-the-sexes. We also find that unbiasedness, known to be a crucial characteristic of allocation fairness, is important to procedural fairness: in the context of a random offer game, a biased outcome is more readily accepted when chosen by an unbiased random draw than by one that is biased. Procedural fairness is conceptually different than allocation fairness or attribution-based behavior, and none of the current models of fairness and reciprocity captures our results. Post hoc extension of one of these models (ERC) suggests that a deeper understanding of procedural fairness requires further investigation of competing fairness norms.

Welfare comparisons: sequential procedures for heterogenous populations

Some analysts use sequential dominance criteria, and others use equivalence scales in combination with non-sequential dominance tests, to make welfare comparisons of oint distributions of income and needs. In this paper we present a new sequential procedure hich copes with situations in which sequential dominance fails. We also demonstrate that there commendations deriving from the sequential approach are valid for distributions of equivalent income whatever equivalence scale the analyst might adopt. Thus the paper marries together the sequential and equivalizing approaches, seen as alternatives in much previous literature. All results are specified in forms which allow for demographic differences in the populations being compared.

Schistosoma mansoni antigenic extracts obtained by different extraction procedures

Solubilization of Schistosoma mansoni antigens was obtained by agitation of adult worms in a 3M KCl solution. The protein contents of the KCl extrats varied from 0.35 to 0.96 mg/ml. Sera from 97 patients with hepatointestinal shistosomiasis and viable eggs in stools from a Brazilian endemic area were studied by immunoelectroomophoresis and Ouchterlony immunodiffusion methods with the KCl extract and with another antigen, obtained by homogenization of adult schistosomes in saline. The rate of positiveness of immunoprecipitation deterctions by immunoelectroomophoresis with the KCl extract was 53.5%. A correlation was verified between methods of detection and extration procedures, resulting in a better association of the extract obtained by agitation in 3M KCl and immunoelectroomophoresis.

Gastric supply manipulation to modulate ghrelin production and enhance vascularization to the cardia: proof of the concept in a porcine model.

Introduction. Selective embolization of the left-gastric artery (LGA) reduces levels of ghrelin and achieves significant short-term weight loss. However, embolization of the LGA would prevent the performance of bariatric procedures because the high-risk leakage area (gastroesophageal junction [GEJ]) would be devascularized. Aim. To assess an alternative vascular approach to the modulation of ghrelin levels and generate a blood flow manipulation, consequently increasing the vascular supply to the GEJ. Materials and methods. A total of 6 pigs underwent a laparoscopic clipping of the left gastroepiploic artery. Preoperative and postoperative CT angiographies were performed. Ghrelin levels were assessed perioperatively and then once per week for 3 weeks. Reactive oxygen species (ROS; expressed as ROS/mg of dry weight [DW]), mitochondria respiratory rate, and capillary lactates were assessed before and 1 hour after clipping (T0 and T1) and after 3 weeks of survival (T2), on seromuscular biopsies. A celiac trunk angiography was performed at 3 weeks. Results. Mean (±standard deviation) ghrelin levels were significantly reduced 1 hour after clipping (1902 ± 307.8 pg/mL vs 1084 ± 680.0; P = .04) and at 3 weeks (954.5 ± 473.2 pg/mL; P = .01). Mean ROS levels were statistically significantly decreased at the cardia at T2 when compared with T0 (0.018 ± 0.006 mg/DW vs 0.02957 ± 0.0096 mg/DW; P = .01) and T1 (0.0376 ± 0.008mg/DW; P = .007). Capillary lactates were significantly decreased after 3 weeks, and the mitochondria respiratory rate remained constant over time at the cardia and pylorus, showing significant regional differences. Conclusions. Manipulation of the gastric flow targeting the gastroepiploic arcade induces ghrelin reduction. An endovascular approach is currently under evaluation.

Stent retriever use for retrieval of displaced microcoils: a consecutive case series.

SUMMARY: Coil displacement during endovascular coiling procedures may require coil retrieval in the context of flow limitation or thromboembolic risk. No standard recommended method of coil retrieval exists. We present a consecutive series of 14 patients with displaced coil during aneurysm coiling in whom the complication was effectively managed with the use of a stent retriever system. Two illustrative cases from the 14 are described, and technical notes are detailed regarding use of the technique. The use of stent retrievers presents a simple, safe, and effective choice for removal of prolapsed coils during aneurysm coiling.

A Comparison Of Forecasting Procedures For Macroeconomic Series: The Contribution Of Structural Break Models

This paper compares the forecasting performance of different models which have been proposed for forecasting in the presence of structural breaks. These models differ in their treatment of the break process, the parameters defining the model which applies in each regime and the out-of-sample probability of a break occurring. In an extensive empirical evaluation involving many important macroeconomic time series, we demonstrate the presence of structural breaks and their importance for forecasting in the vast majority of cases. However, we find no single forecasting model consistently works best in the presence of structural breaks. In many cases, the formal modeling of the break process is important in achieving good forecast performance. However, there are also many cases where simple, rolling OLS forecasts perform well.