Multifractal regime transition in a modified minority game model

The search for more realistic modeling of financial time series reveals several stylized facts of real markets. In this work we focus on the multifractal properties found in price and index signals. Although the usual minority game (MG) models do not exhibit multifractality, we study here one of its variants that does. We show that the nonsynchronous MG models in the nonergodic phase is multifractal and in this sense, together with other stylized facts, constitute a better modeling tool. Using the structure function (SF) approach we detected the stationary and the scaling range of the time series generated by the MG model and, from the linear (non-linear) behavior of the SF we identified the fractal (multifractal) regimes. Finally, using the wavelet transform modulus maxima (WTMM) technique we obtained its multifractal spectrum width for different dynamical regimes. (C) 2009 Elsevier Ltd. All rights reserved.

Recommendations for folate intake in women: implications for public health strategies

Folate deficiency has been associated with anemia and other adverse outcomes in pregnancy such as neural tube defects. The current recommendations for prevention of such outcomes are difficult to achieve through diet only, and folic acid supplementation and food fortification are feasible public health strategies. However, it is necessary to determine the usual diet and supplement use among women of reproductive age, including an accurate assessment of other dietary micronutrients. In addition to the beneficial effects observed in randomized clinical trials, health risks to the population have also been widely evaluated and discussed in the scientific community: for a minority to benefit from fortification programs, many are exposed to high folic acid intake levels.

Genetic Background of Patients from a University Medical Center in Manhattan: Implications for Personalized Medicine

Background: The rapid progress currently being made in genomic science has created interest in potential clinical applications; however, formal translational research has been limited thus far. Studies of population genetics have demonstrated substantial variation in allele frequencies and haplotype structure at loci of medical relevance and the genetic background of patient cohorts may often be complex. Methods and Findings: To describe the heterogeneity in an unselected clinical sample we used the Affymetrix 6.0 gene array chip to genotype self-identified European Americans (N = 326), African Americans (N = 324) and Hispanics (N = 327) from the medical practice of Mount Sinai Medical Center in Manhattan, NY. Additional data from US minority groups and Brazil were used for external comparison. Substantial variation in ancestral origin was observed for both African Americans and Hispanics; data from the latter group overlapped with both Mexican Americans and Brazilians in the external data sets. A pooled analysis of the African Americans and Hispanics from NY demonstrated a broad continuum of ancestral origin making classification by race/ethnicity uninformative. Selected loci harboring variants associated with medical traits and drug response confirmed substantial within-and between-group heterogeneity. Conclusion: As a consequence of these complementary levels of heterogeneity group labels offered no guidance at the individual level. These findings demonstrate the complexity involved in clinical translation of the results from genome-wide association studies and suggest that in the genomic era conventional racial/ethnic labels are of little value.

Experimental Infection of Rhipicephalus sanguineus Ticks with the Bacterium Rickettsia rickettsii, Using Experimentally Infected Dogs

We evaluated if Rickettsia rickettsii-experimentally infected dogs could serve as amplifier hosts for Rhipicephalus sanguineus ticks. In addition, we checked if Rh. sanguineus ticks that acquired Ri. rickettsii from dogs could transmit the bacterium to susceptible hosts (vector competence), and if these ticks could maintain the bacterium by transstadial and transovarial transmissions. Uninfected larvae, nymphs, and adults of Rh. sanguineus were allowed to feed upon three groups of dogs: groups 1 (G1) and 2 (G2) composed of Ri. rickettsii-infected dogs, infected intraperitoneally and via tick bites, respectively, and group 3 composed of uninfected dogs. After larval and nymphal feeding on rickettsemic dogs, 7.1-15.2% and 35.8-37.9% of the molted nymphs and adults, respectively, were shown by polymerase chain reaction (PCR) to be infected by Ri. rickettsii, confirming that both G1 and G2 dogs were efficient sources of rickettsial infection (amplifier host), resulting in transstadial transmission of the agent. These infected nymphs and adults successfully transmitted Ri. rickettsii to guinea pigs, confirming vector competence after acquisition of the infection from rickettsemic dogs. Transovarial transmission of Ri. rickettsii was observed in engorged females that had been infected as nymphs by feeding on both G1 and G2 dogs, but not in engorged females that acquired the infection during adult feeding on these same dogs. In the first case, filial infection rates were generally <50%. No tick exposed to G3 dogs was infected by rickettsiae in this study. No substantial mortality difference was observed between Ri. rickettsii-infected tick groups (G1 and G2) and uninfected tick group (G3). Our results indicate that dogs can be amplifier hosts of Ri. rickettsii for Rh. sanguineus, although only a minority of immature ticks (<45%) should become infected. It appears that Rh. sanguineus, in the absence of horizontal transmission, would not maintain Ri. rickettsii through successive generations, possibly because of low filial infection rates.

Evaluation of Several Carbon-Supported Nanostructured Ni-Doped Manganese Oxide Materials for the Electrochemical Reduction of Oxygen

Physical and electrochemical properties of nanostructured Ni-doped manganese oxides (MnO(x)) catalysts supported on different carbon powder substrates were investigated so as to characterize any carbon substrate effect toward the oxygen reduction reaction (ORR) kinetics in alkaline medium. These NiMnO(x)/C materials were characterized using physicochemical analyses. Small insertion of Ni atoms in the MnO(x) lattice was observed, which consists of a true doping of the manganese oxide phase. The corresponding NiMnO(x) phase is present in the form of needles or agglomerates, with crystallite sizes in the order of 1.5-6.7 nm (from x-ray diffraction analyses). Layered manganite (MnOOH) phase has been detected for the Monarch 1000-supported NiMnO(x) material, while different species of MnO(x) phases are present at the E350G and MM225 carbons. Electrochemical studies in thin porous coating active layers in the rotating ring-disk electrode setup revealed that the MnO(x) catalysts present better ORR kinetics and electrochemical stability upon Ni doping. The ORR follows the so-called peroxide mechanism on MnO(x)/C catalysts, with the occurrence of minority HO(2)(-) disproportionation reaction. The HO(2)(-) disproportionation reaction progressively increases with the Ni content in NiMnO(x) materials. The catalysts supported on the MM225 and E350G carbons promote faster disproportionation reaction, thus leading to an overall four-electron ORR pathway. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3528439] All rights reserved.

Symptoms after mould exposure including Stachybotrys chartarum, and comparison with darkroom disease

P>Background: Mould-attributed symptoms have included features which overlap with unexplained syndromes such as sick building syndrome. Objectives: We describe questionnaire and chart review findings in patients following exposure to moulds which include Stachybotrys and compare responses with two control groups. Methods: Thirty-two patients presented with symptoms attributed to mould exposures. Exposure identification for 25 patients had reported S tachybotrys chartarum as well as other mould (Aspergillus, Penicillium), 88% at work. The remaining seven had professionally visualized or self-reported/photographic exposure evidence only. A chart review was performed and a follow-up with a questionnaire, including questions on current health status, and nonspecific symptoms. Results: Cough, shortness of breath and chest tightness (at presentation) were reported in 79%, 70% and 64%, respectively, and persisted > 6 weeks in 91%. Skin test(s) were positive to fungal extract(s) in 30%. Seventeen returned questionnaires were obtained 3.1 (SD 0.5) years after the initial clinic assessment. Among this subgroup, persisting asthma-like symptoms and symptoms suggestive of sick building syndrome were frequent, and similar to a group previously assessed for darkroom disease among medical radiation technologists. The mould-exposed group more commonly reported they were bothered when walking in a room with carpets, complained of a chemical or metallic taste in their mouth, and had problems in concentration when compared with a control physiotherapist group (P < 0.005). Conclusions: Although only a minority with health concerns from indoor mould exposure had demonstrable mould-allergy, a significant proportion had asthma-like symptoms. Other symptoms were also common and persistent after the initial implicated exposure.

Real-time quantitative PCR in cerebral toxoplasmosis diagnosis of Brazilian human immunodeficiency virus-infected patients

Cerebral toxoplasmosis is the most common cerebral mass lesion in AIDS patients in Brazil, and results in high mortality and morbidity, despite free access to HAART (highly active antiretroviral treatment). Molecular diagnosis based on conventional PCR (cnPCR) or real-time quantitative PCR (qrtPCR) has been indispensable for definitive diagnosis. We report here the evaluation of qrtPCR with blood and cerebrospinal fluid (CSF) samples from AIDS patients in Brazil. This prospective study was conducted for 2 years, analysing DNA samples extracted from 149 AIDS patients (98 blood and 51 CSF samples) with confirmed clinical and radiological diagnosis The laboratory diagnosis included cnPCR (with the B22/B23 primer set) and indirect immunofluorescence (IF). For qrtPCR, two primer sets were simultaneously designed based on described genes and using a 6-carboxyfluorescein dye-labelled TaqMan MGB (minor groove binder) probe One was Bug, which amplified a sequence from the B1 gene The other was the RETg, which amplified a PCR product of the 529 bp sequence. The overall cnPCR and qrtPCR results were positive results were observed in 33.6% (50) patients The sensitivities were 98% for cnPCR (B22/B23), and 86 and 98% for qrtPCR (B1Tg and RETg, respectively). Negative reactions were observed in 66 4% patients. The specificities were 97% for cnPCR and qrtPCR (B1Tg). and 88.8% for RETg These data show that RETg PCR is highly sensitive as it amplifies a repeat region with many copies; however, its specificity is lower than the other markers However, B1Tg PCR had good specificity, but lower sensitivity Among the patients, 20 had blood and CSF collected simultaneously Thus, their results permitted us to analyse and compare molecular, serological and clinical diagnosis for a better understanding of the different scenarios of laboratorial and clinical diagnosis. For nine patients with confirmed cerebral toxoplasmosis diagnosis, four scenarios were observed: (i) and (ii) negative molecular diagnosis for CSF and positive for blood with variable IF titres for the sera and CSF (negative or positive), (iii) positive molecular diagnosis with CSF and negative with blood, and (iv) positive molecular diagnosis in both samples. In the latter two situations, normally the IF titres in sera and CSF are variable. Other opportunistic infections were shown in 11 patients Despite the IF titres in sera and CSF being variable, all of them had negative molecular diagnosis for both samples qrtPCR allows for a rapid identification of Toxoplasma gondii DNA in patient samples; in a minority of cases discrepancies occur with the cnPCR.

Comparative Prevalence, Correlates of Impairment, and Service Utilization for Eating Disorders Across US Ethnic Groups: Implications for Reducing Ethnic Disparities in Health Care Access for Eating Disorders

Objective: The study compared the prevalence, correlates of functional impairment, and service utilization for eating disorders across Latinos, Asians, and African Americans living in the United States to non-Latino Whites. Method: Pooled data from the NIMH Collaborative Psychiatric Epidemiological Studies (CPES; NIMH, 2007) were used. Results: The prevalence of anorexia nervosa (AN) and binge-eating disorder (BED) were similar across all groups examined, but bulimia nervosa (BN) was more prevalent among Latinos and African Americans than non-Latino Whites. Despite similar prevalence of BED among ethnic groups examined, lifetime prevalence of any binge eating (ABE) was greater among each of the ethnic minority groups in comparison to non-Latino Whites. Lifetime prevalence of mental health service utilization was lower among ethnic minority groups studied than for non-Latino Whites for respondents with a lifetime history of any eating disorder. Discussion: These findings suggest the need for clinician training and health policy interventions to achieve optimal and equitable care for eating disorders across all ethnic groups in the United States. (C) 2010 by Wiley Periodicals, Inc.

Impacts of Animal Traffic on the Brazilian Amazon Parrots (Amazona species) Collection of the Quinzinho de Barros Municipal Zoological Park, Brazil, 1986-2007

Eleven species of Amazon parrots (genus Amazona) are known to occur in Brazil, and nest poaching and illegal traffic pose serious conservation threats to these species. When the illegal owners realize these animals are incompatible with their expectations and lifestyle, or when the police arrests traders and owners, these trafficked animals are often considered unfit for release and sent to local zoos and captive breeders. A retrospective survey of animal and necropsy records from 1986 to 2007 was used to evaluate the impacts of animal traffic on the population composition and mortality patterns of Amazon parrots at the Quinzinho de Barros Municipal Zoological Park, Sorocaba, Brazil. Data were obtained for 374 Amazon parrots of ten Brazilian species, and there was evidence that the studied population could be split into two major groups: a majority belonging to the Amazona aestiva species and a minority belonging to the remaining species. In comparison, the animals of the first group were more frequently admitted from traffic-related origins (98 vs. 75%), had a shorter lifespan (median 301 days vs. 848 days) and a higher mortality within the first year postadmission (54 vs. 37%), were less likely to receive expensive treatments, and were more frequently housed off-exhibit. On an average, parrots were found to have a short postadmission lifespan (median 356 days), with 92.5% of the birds dying within their first five years in captivity. The paper discusses the difficult dilemmas these incoming traffic-related animals pose to zoo management and official anti-traffic policies. Zoo Biol 29:600-614, 2010. (C) 2010 Wiley-Liss, Inc.

A hybrid approach to learn with imbalanced classes using evolutionary algorithms

There is an increasing interest in the application of Evolutionary Algorithms (EAs) to induce classification rules. This hybrid approach can benefit areas where classical methods for rule induction have not been very successful. One example is the induction of classification rules in imbalanced domains. Imbalanced data occur when one or more classes heavily outnumber other classes. Frequently, classical machine learning (ML) classifiers are not able to learn in the presence of imbalanced data sets, inducing classification models that always predict the most numerous classes. In this work, we propose a novel hybrid approach to deal with this problem. We create several balanced data sets with all minority class cases and a random sample of majority class cases. These balanced data sets are fed to classical ML systems that produce rule sets. The rule sets are combined creating a pool of rules and an EA is used to build a classifier from this pool of rules. This hybrid approach has some advantages over undersampling, since it reduces the amount of discarded information, and some advantages over oversampling, since it avoids overfitting. The proposed approach was experimentally analysed and the experimental results show an improvement in the classification performance measured as the area under the receiver operating characteristics (ROC) curve.

Electric field gradients in (111)In-doped (Hf/Zr)(3)Al(2) and (Hf/Zr)(4)Al(3) mixed compounds: ab initio calculations, perturbed angular correlation measurements and site preference

The quadrupolar hyperfine interactions of in-diffused (111)In -> (111)Cd probes in polycrystalline isostructural Zr(4)Al(3) and Hf(4)Al(3) samples containing small admixtures of the phases (Zr/Hf)(3)Al(2) were investigated. A strong preference of (111)In solutes for the contaminant (Zr/Hf)(3)Al(2) minority phases was observed. Detailed calculations of the electric field gradient (EFG) at the Cd nucleus using the full-potential augmented plane wave + local orbital formalism allowed us to assign the observed EFG fractions to the various lattice sites in the (Zr/Hf)(3)Al(2) compounds and to understand the preferential site occupation of the minority phases by the (111)In atoms. The effects of the size of the supercell and relaxation around the oversized In and Cd probe atoms were investigated in detail.

Phenol-furfural resins to elaborate composites, reinforced with sisal fibers - Molecular analysis of resin and properties of composites

Resol type resins were prepared in alkaline conditions (potassium hydroxide or potassium carbonate) using furfural obtained by acid hydrolysis of abundant renewable resources from agricultural and forestry waste residues. The structures of the resins were fully determined by H-1, C-13, and 2D NMR spectrometries with the help of four models compounds synthesized specially for this study. MALDI-Tof mass spectrometry experiments indicated that a majority of linear oligomers and a minority of cyclic ones constituted them. Composites were prepared with furfural-phenol resins and sisal fibers. These fibers were chosen mainly because they came from natural lignocellulosic material and they presented excellent mechanical microscopy images indicated that the composites displayed excellent adhesion between resin and fibers. Impact strength measurement showed that mild conditions were more suitable to prepare thermosets. Nevertheless, mild conditions induced a high-diffusion coefficient for water absorption by composites. Composites with good properties could be prepared using high proportion of materials obtained from biomass without formaldehyde. (c) 2008 Wiley Periodicals, Inc.