Strain origin drives virulence and persistence of Xylella fastidiosa in alfalfa

Generalist pathogens frequently exist as a complex of genetically differentiated strains, which can differ in virulence and transmissibility. A description of the extent to which strain variability mediates host species competence is needed to understand disease dynamics for systems with both host and pathogen strain diversity. This study tested the hypothesis that strain-specific variation of a generalist vector-borne plant pathogen, Xylella fastidiosa, affects disease severity in alfalfa (Medicago sativa) and competence of this crop as a reservoir host. Alfalfa seedlings were inoculated with one of 23 X. fastidiosa isolates collected from different hosts, eight identified as belonging to an almond strain, and the remainder from a grape strain. Pathogen population, symptom severity and infection incidence were compared over five successive harvests. Infected plant size, measured mainly by plant height, internode length and above ground biomass, was reduced up to 50% compared to buffer-inoculated controls, and more severe symptoms were observed at later harvests and for higher pathogen populations. Grape isolates had higher bacterial populations within alfalfa than almond isolates. In addition, infection with grape isolates resulted in more severe alfalfa stunting than that caused by almond isolates. Moreover, there was a strong positive relationship between isolate multiplication rate and both symptom severity and infection persistence (i.e. maintenance of chronic infection within host). Isolates with low initial populations had low incidence at the final harvest, with one isolate dying out altogether. The results showed that X. fastidiosa-genetic diversity contributed to variation in alfalfa disease severity. The results also suggest that pathogen strain may mediate host competence via differences in bacterial population density and persistence.

The Effects of Host, Geographic Origin, and Gender on the Thermal Requirements of Diaphorina citri (Hemiptera: Psyllidae)

Diaphorina citri Kuwayama (Hemiptera: Psyllidae) is the vector of the bacteria that causes citrus greening and is considered one of the world`s most important citrus diseases. We examined how host, geographic region, and gender affect the thermal requirements of D. citri. The insects were reared in climatic chambers at constant temperatures of 18, 20, 22, 25, 28, 30, and 32 1 degrees C, 70 +/- 10% RH, and a 14 h photophase. Host plants for D. citri included orange (Citrus sinensis [Rutaceae]) varieties Pera and Natal, the rootstock, Rungpur lime (C. limonia [Rutaceae]) and the natural host, Orange jessamine (Murraya paniculata [Rutaceae]). To study the influence of geographic origin on thermal requirements, we studied D. citri populations from Piracicaba, SP (warmer region) and Itapetininga, SP (cooler region). The duration and survival of the development stages and the duration of the total development (egg-adult) did not differ significantly on the different hosts, but it did vary with temperature. Nymphs of D. citri created on the different hosts have the same thermal requirements. The thermal requirements for this species collected from the two climate regions were identical; males and females also had the same thermal requirements.

Enterotoxigenic and genetic profiles of Bacillus cereus strains of food origin in Brazil

In Brazil. the incidence of Bacillus cereus outbreaks is unknown, and there is little information about B. cereus occurrence in food. In addition, data on toxin production and genetic characterization of the B. cereus isolates cannot be found. This pathogen causes two distinct types of toxin-mediated foodborne illnesses known as diarrheal and emetic syndromes. Diarrheal syndrome has been linked to three different enterotoxins: two protein complexes, hemolysin BL (HBL) and nonhemolytic enterotoxin (NHE); and an enterotoxic protein, cytotoxin K (cytK). Emetic syndrome is related to cereulide, a toxin encoded by the ces gene. In this study, NHE and HBL production capacities of 155 strains of B. cereus isolated from Brazilian food products were evaluated with an immunoassay. Strains were also tested for the presence of the genes of the HBL and NHE complexes, cytK, cytK-1, cytK-2, and ces, using PCR. HBL was detected in 105 (67.7%) strains and NHE in 154 (99.4%) strains. All the strains harbored at least one gene of the NHE complex, while 96.1% of them were positive for at least one of those of the HBL complex. Genes cytK1 and ces were not detected. All strains showed toxigenic capacity and could represent a risk for consumers if good practices are not followed. This is the first report on toxigenic and genetic profiles of B. cereus strains isolated in Brazil.

A survey on the sanitary condition of commercial foods of plant origin sold in Brazil

The objective of the study was to evaluate the hygienic conditions and practices of commercial foods of plant origin in establishments and street marketed by street vendors in cities in the State of Rio de Janeiro, Brazil. Forty different sales points were evaluated (establishments that prepared and sold fruit juices and street vendors that commercialized fresh coconut water, sugarcane juice and orange juice) using a questionnaire with 12 items, divided into three blocks (salesmen/handlers, operations, installations). The results indicated that the activities related to the commerce of fruit beverages in the cities of Sao Goncalo and Rio de Janeiro required the elaboration of a set of actions by the Sanitary Vigilance Agency in order to improve the hygienic and sanitary level and minimize health risk to consumers. Important requirements in the legislation relevant to this type of food are still not followed; adequate packaging and storage of the raw material, obtaining the raw material from registered suppliers, hygiene of the handlers and adequate management of wastes produced during the activities in question are amongst the main items deserving attention. (C) 2009 Elsevier Ltd. All rights reserved.

IB Theory and the Entry of MNCs in Brazil from 1850 to 2007

This paper analyses the applicability of the main enterprise internationalization theories to the entry of the multinational corporations into Brazil, throughout five phases of Brazilian economy, from 1850 to nowadays. It seeks to verify the explanation power of each theory over the FDI flows in Brazil. It concludes that there is a contingency relation between the theories and the phases of the economy, and. it shows such relationship in a table. In addition, it concludes that the most powerful theory along the researched period was Dunning`s eclectic paradigm, mainly due to the Localization considerations. Theoretical propositions are put forward as a contribution to future research.

Stakeholders Theory and Theory of the Firm: a study on the hierarchy of objective-functions in Brazilian companies

Discussion opposing the Theory of the Firm to the Theory of Stakeholders are contemporaneous and polemical. One focal point of such debates refers to which objective-function companies, should choose, whether that of the shareholders or that of the stakeholders, and whether it is possible to opt for both simultaneously. Several empirical studies. have attempted-to test a possible correlation between both functions, and there has not been any consensus-so far. The objective of the present research is to examine a gap in such discussions: is there (or not) a subordination of the stakeholders` objective-function to that of the shareholders? The research is empirical,and analytical and employs quantitative methods. Hypotheses were tested and data analyzed by using non-parametrical (chi-square test) and parametrical procedures (frequency. correlation `coefficient). Secondary data was collected from he Economitica database and from the Brazilian Institute of Social and-Economic Analyses (IBASE) website, relative to public companies that have published their Social Balance Statements following the IBASE model from 1999 to 2006, whose sample amounted to 65 companies; In order to assess the objective-function of shareholders a proxy was created based on the following three indices: ROE (return on equity), EnterpriseValue and Tobin`s Q. In order to assess the objective-function of stakeholders a proxy was created by employing the following IBASE social balance indices: internal ones (ISI), external ones (ISE), and environmental ones (IAM). The results have shown no evidence of subordination of stakeholders` objective-function to that of the shareholders in analyzed companies, negating initial expectations and calling for deeper investigation of results. Its main conclusion, which states that the attempted subordination does not take place, is limited to the sample herein investigated and calls for ongoing research aiming at improvements which may lead to sample enlargement and, as a consequence, may make feasible the application of other statistical techniques which may yield a more thorough, analysis of the studied phenomehon.

Personal values and the `country-of-origin effect`: the moderating role of consumers` demographics

This article has addressed the following research problem: what consumers` personal values most influence the country-of-origin effect? Furthermore, it has verified whether there are differences on this influence, in terms of consumers` demographic characteristics such as gender, age and country familiarity. A descriptive and quantitative empirical research has been used to analyse the product category of Chinese home appliances, using a sample of Brazilian executives. Results have shown that consumers` personal values exert different influences on the evaluation of foreign products. Most influences of personal values on the country-of-origin effect are negative; the more important the personal values, the more negative the products are evaluated. Exceptions are for women. With the results of this research, marketing professionals and theoreticians may better manage the use of a product`s country of origin as a marketing tool in international marketing activities.

On recent developments in the theory of abstract differential equations with fractional derivatives

This note is motivated from some recent papers treating the problem of the existence of a solution for abstract differential equations with fractional derivatives. We show that the existence results in [Agarwal et al. (2009) [1], Belmekki and Benchohra (2010) [2], Darwish et al. (2009) [3], Hu et al. (2009) [4], Mophou and N`Guerekata (2009) [6,7], Mophou (2010) [8,9], Muslim (2009) [10], Pandey et al. (2009) [11], Rashid and El-Qaderi (2009) [12] and Tai and Wang (2009) [13]] are incorrect since the considered variation of constant formulas is not appropriate. In this note, we also consider a different approach to treat a general class of abstract fractional differential equations. (C) 2010 Elsevier Ltd. All rights reserved.

Parvovirus among Patients with Cytopenia of Unknown Origin in Brazil: a Case-Control Study

The molecular prevalence of human parvovirus B19V (B19V) in bone marrow (BM) samples from 120 cases with cytopenias of unknown etiology was compared with that in samples from 45 BM donors (control group 1) and 120 oncohematological patients (control group 2) to determine the role that B19V genotypes may play in unexplained cytopenias. Of the 285 participants, the BM samples of 39 (13.7%) contained B19V DNA (21 with genotype 1, 5 with genotype 2, and 13 with genotype 3). The prevalences of B19V were similar between case and control subjects (15.0% versus 12.7%, respectively). Genotypes 2 and 3 were associated with older age and were detected in similar proportions between case and control group 2 subjects. The results of this study do not support a role for B19V genotype variants in the etiology of unexplained cytopenias.

The efficacy of functional endoscopic sinus surgery in the evolution of fever of unknown origin in ICU patients

Conclusion: Functional endoscopic sinus surgery (FESS) was found to be effective in treating fever of unknown origin (FUO) in intensive care unit (ICU) patients with rhinosinusitis, with 62% of patients showing improvement within 5 days of the procedure. Objective: To correlate improvement in FUO with FESS drainage of the paranasal sinuses. Methods: Fifty patients that developed FUO during ICU stay, with CT findings suggestive of rhinosinusitis, and showed no improvement in fever after clinical treatment underwent FESS for drainage of the paranasal sinuses and were evaluated for postoperative improvement of fever. Results: The study sample consisted of 50 patients (74% of whom were male, mean age 48.1 years). The most frequent diagnoses at ICU admission were tetanus, pulmonary disease, and cardiovascular disease. In all, 68% of patients underwent nasogastric or enteral intubation. CT scanning most commonly showed involvement of the sphenoid sinus. In 54% of cases, sinusitis was bilateral and extended throughout the maxillary, ethmoidal, and sphenoidal sinuses. Sinusectomy was performed in all patients, and pathological secretion in the paranasal sinuses was seen in 52% of patients during surgery. Gram-negative bacteria were the most commonly isolated organisms, followed by Gram-positive bacteria and fungi. Improvement of fever was found in 82% of patients after FESS; 38% of these improved within the first 48 h post-procedure, and the remaining 62% within the first 5 postoperative days.

ADHD in a representative sample of the Brazilian population: estimated prevalence and comparative adequacy of criteria between adolescents and adults according to the item response theory

Background: Attention deficit hyperactivity disorder (ADHD) is a clinically significant disorder in adulthood, but current diagnostic criteria and instruments do not seem to adequately capture the complexity of the disorder in this developmental phase. Accordingly, there are limited data on the proportion of adults affected by the disorder, specially in developing countries. Method: We assessed a representative household sample of the Brazilian population for ADHD with the Adult ADHD Self-report Scale (ASRS) Screener, and evaluated the instrument according to the Rasch model of item response theory. Results: The sample was comprised by 3007 individuals, and the overal prevalence of positive screeners for ADHD was 5.8% [95% confidence interval (CI), 4.8-7.0]. Rasch analyses revealed the misfitt of the overall sample to expectations of the model. The evaluation of the sample stratified by age revealed that data for adolescents showed a signficant fittnes to the model expectations, while items completed by adults were not adequated. Conclusions: The lack of fitness to the model for adult respondents challenges the possibility of a linear transformation of the ordinal data into interval measures and the utilization of parametric analyses of data. This result suggests that diagnostic criteria and instruments for adult ADHD must take into account a developmental perspective. Moreover, it calls for further evaluation of currently employed research methods in light of modern theories of psychometrics. Copyright (C) 2010 John Wiley & Sons, Ltd.

Is Chlamydia-infected tubal fimbria the origin of ovarian cancer?

Ovarian cancer is a highly lethal disease and its underlying biology is poorly understood. Prophylactic salpingo-oophorectomies in BRCA + women have recently implicated the fimbria as a site of origin for high-grade serous carcinoma and its intraepithelial precursors. This suggests that at least some ovarian cancers, probably the most aggressive ones, may not originate in the ovary itself, but rather may arise in the uterine tubes. Chronic inflammation is associated with carcinogenesis in several tissues, including liver, esophagogastric junction (cardia), and the uterine cervix. The mechanisms underlying the relationship between inflammation and cancer are complex and involve common pathways, in addition to DNA damage. A critical source of uterine tube inflammation is infection with Chlamydia trachomatis. We hypothesize that C. trachomatis infection may be involved in chronic tubal, inflammation and subsequent fimbrial carcinogenesis. Fimbrial intraepithelial precursors can evolve into high grade serous carcinomas that spread rapidly to the ovarian surface and peritoneum; such tumors may appear to be primary ovarian neoplasia, though in reality being a secondary malignancy. This hypothesis must be further investigated to understand the intracellular signaling pathways involved in Chlamydia infection and its heating, and their relationship to carcinogenesis in order to discover potential therapeutic molecular targets. If our hypothesis were confirmed, salpingectomy instead of ovariectomy may also become the recommended surgery for high risk women. (C) 2008 Elsevier Ltd. All rights reserved.

Microscopic origin of non-Gaussian distributions of financial returns

In this paper we study the possible microscopic origin of heavy-tailed probability density distributions for the price variation of financial instruments. We extend the standard log-normal process to include another random component in the so-called stochastic volatility models. We study these models under an assumption, akin to the Born-Oppenheimer approximation, in which the volatility has already relaxed to its equilibrium distribution and acts as a background to the evolution of the price process. In this approximation, we show that all models of stochastic volatility should exhibit a scaling relation in the time lag of zero-drift modified log-returns. We verify that the Dow-Jones Industrial Average index indeed follows this scaling. We then focus on two popular stochastic volatility models, the Heston and Hull-White models. In particular, we show that in the Hull-White model the resulting probability distribution of log-returns in this approximation corresponds to the Tsallis (t-Student) distribution. The Tsallis parameters are given in terms of the microscopic stochastic volatility model. Finally, we show that the log-returns for 30 years Dow Jones index data is well fitted by a Tsallis distribution, obtaining the relevant parameters. (c) 2007 Elsevier B.V. All rights reserved.

DOUBLE ANEUPLOIDY (48,XXY,+21) OF MATERNAL ORIGIN IN A CHILD BORN TO A 13-YEAR-OLD MOTHER: EVALUATION OF THE MATERNAL FOLATE METABOLISM

Double aneuploidy, (48,XXY,+21) of maternal origin in a child born to a 13-year-old mother: evoluation of the maternal folate metabolism: The occurrence of non-mosaic double trisomy is exceptional in newborns. In this paper, a 48,XXY,+21 child, the parental origin of the extra chromosomes and the evaluation of the maternal folate metabolism are presented. The infant was born to a 13-year-old mother and presented with the typical clinical features of Down syndrome (DS). The origin of the additional chromosomes was maternal and most likely resulted from errors during the first meiotic division. Molecular analysis of 12 genetic polymorphisms involved in the folate metabolism revealed that the mother is heterozygous for the MTHFR C677T and TC2 A67G polymorphisms, and homozygous for the mutant MTRR A66G polymorphism. The maternal homocysteine concentration was 4.7 mu mol/L, a value close to the one considered as a risk factor for DS in our previous study. Plasma methylmalonic acid and serum folate concentrations were 0.17 mu mol/L and 18.4 ng/mL, respectively. It is possible that the presence of allelic variants for the folate metabolism and Hey concentration might have favored errors in chromosomal disjunction (hiring gametogenesis in this young mother. To our knowledge, this is the first patient with non-mosaic Down-Klinefelter born to a teenage mother, resulting from a rare fertilization event combining an abnormal 25,XX,+21 oocyte and a 23,Y spermatozoon.

Mitochondrial population genomics supports a single pre-Clovis origin with a coastal route for the peopling of the Americas

It is well accepted that the Americas were the last continents reached by modern humans, most likely through Beringia. However, the precise time and mode of the colonization of the New World remain hotly disputed issues. Native American populations exhibit almost exclusively five mitochondrial DNA (mtDNA) haplogroups (A-D and X). Haplogroups A-D are also frequent in Asia, suggesting a northeastern Asian origin of these lineages. However, the differential pattern of distribution and frequency of haplogroup X led some to suggest that it may represent an independent migration to the Americas. Here we show, by using 86 complete mitochondrial genomes, that all Native American haplogroups, including haplogroup X, were part of a single founding population, thereby refuting multiple-migration models. A detailed demographic history of the mtDNA sequences estimated with a Bayesian coalescent method indicates a complex model for the peopling of the Americas, in which the initial differentiation from Asian populations ended with a moderate bottleneck in Beringia during the last glacial maximum (LGM), around similar to 23,000 to similar to 19,000 years ago. Toward the end of the LGM, a strong population expansion started similar to 18,000 and finished similar to 15,000 years ago. These results support a pre-Clovis occupation of the New World, suggesting a rapid settlement of the continent along a Pacific coastal route.