Seroprevalence of Toxoplasma gondii infection in goats by the indirect haemagglutination, immunofluorescence and immunoenzymatic tests in the region of Uberlândia, Brazil

A comparative study of the indirect haemagglutination (IHA), immunofluorescence (IFAT) and immunoenzymatic (ELISA) tests was carried out to determine the prevalence of Toxoplasma gondii antibodies in goats. One hundred seventy-four serum samples were obtained from four goat herds from the region of Uberlândia, State of Minas Gerais. The distribution of the animals, according to their origin, was as follow: 71 from herd I; 39 from herd II; 37 from herd III; and 27 from herd IV. Serum samples were analyzed by IHA, IFAT and ELISA, considering the reactivity of the serum samples at dilution ≥ 1:64 as cut off titer for the three tests. A global seroprevalence of 18.4% was observed, with significantly higher positivity rate in the herd II (66.7%) and older animals (> 36 months). A high and significant positive correlation was found between the titers obtained by the IHA versus IFAT, IHA versus ELISA, and ELISA versus IFAT. Therefore, it can be concluded that the three analyzed tests have shown to be highly concordant and appropriate for epidemiological surveys of Toxoplasma infection in goats. Although the seroprevalence of T. gondii infection in goats is relatively low in this region as compared to other regions of the country, adequate management might be useful and essential to control the infection in the goat herds.

Comparison between precipitin and ELISA tests in the bloodmeal detection of Aedes aegypti (Linnaeus) and Aedes fluviatilis (Lutz) mosquitoes experimentally fed on feline, canine and human hosts

The identification of arthropod bloodmeals is important in many epidemiological studies, as, the understanding of the life cycle of vectors and the patogens they transmit, as well as helping to define arthropods' control strategies. The precipitin test has been used for decades, but ELISA is slowly becoming more popular. To compare the two tests for sensitivity, specificity and accuracy to detect small insect bloodmeals, Aedes aegypti or Ae. fluviatilis mosquitoes were fed either on feline, canine or human hosts. Mosquitoes were frozen at 6, 12, 24, 48 or 72 h after feeding. Precipitin test showed better specificity and accuracy and ELISA test showed higher sensitivity. Better results with both tests were achieved when mosquitoes were frozen within 48 h from feeding.

Essays in higher moment asset pricing and liquidity risk

This thesis focuses on theoretical asset pricing models and their empirical applications. I aim to investigate the following noteworthy problems: i) if the relationship between asset prices and investors' propensities to gamble and to fear disaster is time varying, ii) if the conflicting evidence for the firm and market level skewness can be explained by downside risk, Hi) if costly learning drives liquidity risk. Moreover, empirical tests support the above assumptions and provide novel findings in asset pricing, investment decisions, and firms' funding liquidity. The first chapter considers a partial equilibrium model where investors have heterogeneous propensities to gamble and fear disaster. Skewness preference represents the desire to gamble, while kurtosis aversion represents fear of extreme returns. Using US data from 1988 to 2012, my model demonstrates that in bad times, risk aversion is higher, more people fear disaster, and fewer people gamble, in contrast to good times. This leads to a new empirical finding: gambling preference has a greater impact on asset prices during market downturns than during booms. The second chapter consists of two essays. The first essay introduces a foramula based on conditional CAPM for decomposing the market skewness. We find that the major market upward and downward movements can be well preadicted by the asymmetric comovement of betas, which is characterized by an indicator called "Systematic Downside Risk" (SDR). We find that SDR can efafectively forecast future stock market movements and we obtain out-of-sample R-squares (compared with a strategy using historical mean) of more than 2.27% with monthly data. The second essay reconciles a well-known empirical fact: aggregating positively skewed firm returns leads to negatively skewed market return. We reconcile this fact through firms' greater response to negative maraket news than positive market news. We also propose several market return predictors, such as downside idiosyncratic skewness. The third chapter studies the funding liquidity risk based on a general equialibrium model which features two agents: one entrepreneur and one external investor. Only the investor needs to acquire information to estimate the unobservable fundamentals driving the economic outputs. The novelty is that information acquisition is more costly in bad times than in good times, i.e. counter-cyclical information cost, as supported by previous empirical evidence. Later we show that liquidity risks are principally driven by costly learning. Résumé Cette thèse présente des modèles théoriques dévaluation des actifs et leurs applications empiriques. Mon objectif est d'étudier les problèmes suivants: la relation entre l'évaluation des actifs et les tendances des investisseurs à parier et à crainadre le désastre varie selon le temps ; les indications contraires pour l'entreprise et l'asymétrie des niveaux de marché peuvent être expliquées par les risques de perte en cas de baisse; l'apprentissage coûteux augmente le risque de liquidité. En outre, des tests empiriques confirment les suppositions ci-dessus et fournissent de nouvelles découvertes en ce qui concerne l'évaluation des actifs, les décisions relatives aux investissements et la liquidité de financement des entreprises. Le premier chapitre examine un modèle d'équilibre où les investisseurs ont des tendances hétérogènes à parier et à craindre le désastre. La préférence asymétrique représente le désir de parier, alors que le kurtosis d'aversion représente la crainte du désastre. En utilisant les données des Etats-Unis de 1988 à 2012, mon modèle démontre que dans les mauvaises périodes, l'aversion du risque est plus grande, plus de gens craignent le désastre et moins de gens parient, conatrairement aux bonnes périodes. Ceci mène à une nouvelle découverte empirique: la préférence relative au pari a un plus grand impact sur les évaluations des actifs durant les ralentissements de marché que durant les booms économiques. Exploitant uniquement cette relation générera un revenu excédentaire annuel de 7,74% qui n'est pas expliqué par les modèles factoriels populaires. Le second chapitre comprend deux essais. Le premier essai introduit une foramule base sur le CAPM conditionnel pour décomposer l'asymétrie du marché. Nous avons découvert que les mouvements de hausses et de baisses majeures du marché peuvent être prédits par les mouvements communs des bêtas. Un inadicateur appelé Systematic Downside Risk, SDR (risque de ralentissement systématique) est créé pour caractériser cette asymétrie dans les mouvements communs des bêtas. Nous avons découvert que le risque de ralentissement systématique peut prévoir les prochains mouvements des marchés boursiers de manière efficace, et nous obtenons des carrés R hors échantillon (comparés avec une stratégie utilisant des moyens historiques) de plus de 2,272% avec des données mensuelles. Un investisseur qui évalue le marché en utilisant le risque de ralentissement systématique aurait obtenu une forte hausse du ratio de 0,206. Le second essai fait cadrer un fait empirique bien connu dans l'asymétrie des niveaux de march et d'entreprise, le total des revenus des entreprises positiveament asymétriques conduit à un revenu de marché négativement asymétrique. Nous décomposons l'asymétrie des revenus du marché au niveau de l'entreprise et faisons cadrer ce fait par une plus grande réaction des entreprises aux nouvelles négatives du marché qu'aux nouvelles positives du marché. Cette décomposition révélé plusieurs variables de revenus de marché efficaces tels que l'asymétrie caractéristique pondérée par la volatilité ainsi que l'asymétrie caractéristique de ralentissement. Le troisième chapitre fournit une nouvelle base théorique pour les problèmes de liquidité qui varient selon le temps au sein d'un environnement de marché incomplet. Nous proposons un modèle d'équilibre général avec deux agents: un entrepreneur et un investisseur externe. Seul l'investisseur a besoin de connaitre le véritable état de l'entreprise, par conséquent, les informations de paiement coutent de l'argent. La nouveauté est que l'acquisition de l'information coute plus cher durant les mauvaises périodes que durant les bonnes périodes, comme cela a été confirmé par de précédentes expériences. Lorsque la récession comamence, l'apprentissage coûteux fait augmenter les primes de liquidité causant un problème d'évaporation de liquidité, comme cela a été aussi confirmé par de précédentes expériences.

Statistical tests for scaling in the inter-event times of earthquakes in California

We explore in depth the validity of a recently proposed scaling law for earthquake inter-event time distributions in the case of the Southern California, using the waveform cross-correlation catalog of Shearer et al. Two statistical tests are used: on the one hand, the standard two-sample Kolmogorov-Smirnov test is in agreement with the scaling of the distributions. On the other hand, the one-sample Kolmogorov-Smirnov statistic complemented with Monte Carlo simulation of the inter-event times, as done by Clauset et al., supports the validity of the gamma distribution as a simple model of the scaling function appearing on the scaling law, for rescaled inter-event times above 0.01, except for the largest data set (magnitude greater than 2). A discussion of these results is provided.

Rapid diagnostic tests for the home-based management of malaria, in a high-transmission area.

Rapid diagnostic tests (RDT) are sometimes recommended to improve the home-based management of malaria. The accuracy of an RDT for the detection of clinical malaria and the presence of malarial parasites has recently been evaluated in a high-transmission area of southern Mali. During the same study, the cost-effectiveness of a 'test-and-treat' strategy for the home-based management of malaria (based on an artemisinin-combination therapy) was compared with that of a 'treat-all' strategy. Overall, 301 patients, of all ages, each of whom had been considered a presumptive case of uncomplicated malaria by a village healthworker, were checked with a commercial RDT (Paracheck-Pf). The sensitivity, specificity, and positive and negative predictive values of this test, compared with the results of microscopy and two different definitions of clinical malaria, were then determined. The RDT was found to be 82.9% sensitive (with a 95% confidence interval of 78.0%-87.1%) and 78.9% (63.9%-89.7%) specific compared with the detection of parasites by microscopy. In the detection of clinical malaria, it was 95.2% (91.3%-97.6%) sensitive and 57.4% (48.2%-66.2%) specific compared with a general practitioner's diagnosis of the disease, and 100.0% (94.5%-100.0%) sensitive but only 30.2% (24.8%-36.2%) specific when compared against the fulfillment of the World Health Organization's (2003) research criteria for uncomplicated malaria. Among children aged 0-5 years, the cost of the 'test-and-treat' strategy, per episode, was about twice that of the 'treat-all' (U.S.$1.0. v. U.S.$0.5). In older subjects, however, the two strategies were equally costly (approximately U.S.$2/episode). In conclusion, for children aged 0-5 years in a high-transmission area of sub-Saharan Africa, use of the RDT was not cost-effective compared with the presumptive treatment of malaria with an ACT. In older patients, use of the RDT did not reduce costs. The question remains whether either of the strategies investigated can be made affordable for the affected population.

Los tests proyectivos en la comprensión de la recepción del arte gráfico

Una aproximació a la psicologia de la recepció de l'obra d'art a partir dels tests projectius.

Tests de conduir amb .NET i AJAX autotest

Es tracta d'una aplicació Web que serveix perquè les persones puguin practicar i millorar els seus coneixements de cara a l'examen teòric de conduir. S'ha realitzat l'anàlisi, el disseny i la implementació utilitzant una arquitectura .NET amb 4 capes.

Evaluation of tests based on the antibody response to keyhole limpet haemocyanin and soluble egg antigen to differentiate acute and chronic human schistosomiasis mansoni

Specific IgG and IgM responses to soluble egg antigen (SEA) and keyhole limpet haemocyanin (KLH) were measured by ELISA in patients with acute and chronic schistosomiasis. The tests based upon IgM and IgG antibodies responses to KLH presented the best diagnostic discrimination, and can be used in conjunction with clinical and epidemiological data to the differential diagnosis of acute schistosomiasis.

Conducting and Interpreting Appropriate Hypotheses Tests (Part 2)

Catherine Comiskey CI and Hypothesis tests part 2 Hypothesis Testing   - Developing Null and Alternative Hypotheses   - Type I and Type II Errors   - Population Mean:  s Known   - Population Mean:  s Unknown   - Population Proportion  

Conducting and Interpreting Appropriate Hypotheses Tests

Catherine Comiskey CI and Hypothesis tests part 1 Hypothesis Testing   -  Developing Null and Alternative Hypotheses   -  Type I and Type II Errors   -   Population Mean:  S Known   -  Population Mean:  S Unknown   -  Population Proportion  

Evaluation of five screening tests licensed in Argentina for detection of hepatitis C virus antibodies

This study was conducted to compare among the most recent generation of five screening tests licensed in Argentina, in order to evaluate which of the tests has the best sensitivity for detection of antibodies against hepatitis C virus (HCV). The tests analyzed were: Detect-HCV™ (3.0) Biochem ImmunoSystems, Canada; Hepatitis C EIA Wiener Lab., Argentina; Equipar HCV Ab, Italy; Murex HCV 4.0, UK and Serodia-HCV particles agglutination test, Japan. The results obtained showed high discrepancy between the different kits used and show that some of the tests assessed have a low sensitivity for anti-HCV detection in both chronic infections and early seroconversion, and indicate that among the commercially available kits in Argentina, Murex HCV 4.0 (UK) and Serodia-HCV particles agglutination test (Japan) have the best sensitivity for HCV screening. Although the sensitivity of the assays is the first parameter to be considered for blood screening, more studies should be carried out to assess the specificity of such assays.

Radiosensibilité individuelle : les tests vont changer nos pratiques [Intrinsic radiosensitivity: predictive assays that will change the daily practice].

The impact of curative radiotherapy depends mainly on the total dose delivered homogenously in the targeted volume. Nevertheless, the dose delivered to the surrounding healthy tissues may reduce the therapeutic ratio of many radiation treatments. In a same population treated in one center with the same technique, it appears that individual radiosensitivity clearly exists, namely in terms of late side effects that are in principle non-reversible. This review details the different radiobiological approaches that have been developed to better understand the mechanisms of radiation-induced late effects. We also present the possibilities of clinical use of predictive assays in the close future.

Plutonium from above-ground nuclear tests in milk teeth: investigation of placental transfer in children born between 1951 and 1995 in Switzerland.

BACKGROUND: Occupational risks, the present nuclear threat, and the potential danger associated with nuclear power have raised concerns regarding the metabolism of plutonium in pregnant women. OBJECTIVE: We measured plutonium levels in the milk teeth of children born between 1951 and 1995 to assess the potential risk that plutonium incorporated by pregnant women might pose to the radiosensitive tissues of the fetus through placenta transfer. METHODS: We used milk teeth, whose enamel is formed during pregnancy, to investigate the transfer of plutonium from the mother's blood plasma to the fetus. We measured plutonium using sensitive sector field inductively coupled plasma mass spectrometry techniques. We compared our results with those of a previous study on strontium-90 ((90)Sr) released into the atmosphere after nuclear bomb tests. RESULTS: Results show that plutonium activity peaks in the milk teeth of children born about 10 years before the highest recorded levels of plutonium fallout. By contrast, (90)Sr, which is known to cross the placenta barrier, manifests differently in milk teeth, in accordance with (90)Sr fallout deposition as a function of time. CONCLUSIONS: These findings demonstrate that plutonium found in milk teeth is caused by fallout that was inhaled around the time the milk teeth were shed and not from any accumulation during pregnancy through placenta transfer. Thus, plutonium may not represent a radiologic risk for the radiosensitive tissues of the fetus.

Protecting you and your baby: Blood tests at your first antenatal visit

This leaflet gives information on the blood tests that are normally offered and recommended at the first antenatal visit. These tests look for possible health problems that could affect the mother's health and the health of the baby. Only one sample of blood is needed to do all six tests. The tests are done by consent and this leaflet should help pregnant women make their decision.