The evolution of XY recombination: sexually antagonistic selection versus deleterious mutation load.

Recombination arrest between X and Y chromosomes, driven by sexually antagonistic genes, is expected to induce their progressive differentiation. However, in contrast to birds and mammals (which display the predicted pattern), most cold-blooded vertebrates have homomorphic sex chromosomes. Two main hypotheses have been proposed to account for this, namely high turnover rates of sex-determining systems and occasional XY recombination. Using individual-based simulations, we formalize the evolution of XY recombination (here mediated by sex reversal; the "fountain-of-youth" model) under the contrasting forces of sexually antagonistic selection and deleterious mutations. The shift between the domains of elimination and accumulation occurs at much lower selection coefficients for the Y than for the X. In the absence of dosage compensation, mildly deleterious mutations accumulating on the Y depress male fitness, thereby providing incentives for XY recombination. Under our settings, this occurs via "demasculinization" of the Y, allowing recombination in XY (sex-reversed) females. As we also show, this generates a conflict with the X, which coevolves to oppose sex reversal. The resulting rare events of XY sex reversal are enough to purge the Y from its load of deleterious mutations. Our results support the "fountain of youth" as a plausible mechanism to account for the maintenance of sex-chromosome homomorphy.

Management of the risk of HIV infection in male homosexual couples.

OBJECTIVES: To study the ways of managing HIV risk within male homosexual steady relationships (gay couples), including factors associated with consistent condom use during anal sex with the steady partner.¦METHOD: An anonymous and standardized questionnaire completed by a convenience sample of homosexuals in Switzerland in 1997 (n = 1097). Information on the couple was provided by the 74% (n = 786) of male respondents who reported having a steady partner in the past 12 months. Data were analysed by contingency tables and logistic regression.¦RESULTS: Different ways of managing HIV risk were reported: negotiated safety (both HIV negative, condoms abandoned) was chosen by one quarter of the couples, but the most frequent solution was reliance on condoms for anal sex, chosen by more than four in 10. Altogether 84% of couples exhibited safe management of HIV risk within their partnership. The 16% of couples showing inadequate management of HIV risk within the couple mostly relied on questionable assumptions about past or present risks. A total of 74% of couples had spoken about managing HIV risk with possible casual partners. Reported behaviour with the steady partner and with casual partners was highly consistent with claimed strategies chosen to manage HIV risk. Consistent condom use with the steady partner was mostly associated with variables characterizing the relationship: initial 2 years of the relationship, discordant or unknown serological HIV status, non-exclusivity.¦CONCLUSION: Gay couples manage HIV risk in a variety of ways. Most strategies provide adequate protection with casual partners, but leave gaps in protection between the steady partners themselves.

Alpine tectonic evolution of a Jurassic subduction-accretionary complex: Deformation, kinematics and 40Ar/39Ar age constraints on the Mesozoic low-grade schists of the Circum-Rhodope Belt in the eastern Rhodope-Thrace region, Bulgaria-Greece

Deformation of the Circum-Rhodope Belt Mesozoic (Middle Triassic to earliest Lower Cretaceous) low-grade schists underneath an arc-related ophiolitic magmatic suite and associated sedimentary successions in the eastern Rhodope-Thrace region occurred as a two-episode tectonic process: (i) Late Jurassic deformation of arc to margin units resulting from the eastern Rhodope-Evros arc-Rhodope terrane continental margin collision and accretion to that margin, and (ii) Middle Eocene deformation related to the Tertiary crustal extension and final collision resulting in the closure of the Vardar ocean south of the Rhodope terrane. The first deformational event D-1 is expressed by Late Jurassic NW-N vergent fold generations and the main and subsidiary planar-linear structures. Although overprinting, these structural elements depict uniform bulk north-directed thrust kinematics and are geometrically compatible with the increments of progressive deformation that develops in same greenschist-facies metamorphic grade. It followed the Early-Middle Jurassic magmatic evolution of the eastern Rhodope-Evros arc established on the upper plate of the southward subducting Maliac-Meliata oceanic lithosphere that established the Vardar Ocean in a supra-subduction back-arc setting. This first event resulted in the thrust-related tectonic emplacement of the Mesozoic schists in a supra-crustal level onto the Rhodope continental margin. This Late Jurassic-Early Cretaceous tectonic event related to N-vergent Balkan orogeny is well-constrained by geochronological data and traced at a regional-scale within distinct units of the Carpatho-Balkan Belt. Following subduction reversal towards the north whereby the Vardar Ocean was subducted beneath the Rhodope margin by latest Cretaceous times, the low-grade schists aquired a new position in the upper plate, and hence, the Mesozoic schists are lacking the Cretaceous S-directed tectono-metamorphic episode whose effects are widespread in the underlying high-grade basement. The subduction of the remnant Vardar Ocean located behind the colliding arc since the middle Cretaceous was responsible for its ultimate closure, Early Tertiary collision with the Pelagonian block and extension in the region caused the extensional collapse related to the second deformational event D-2. This extensional episode was experienced passively by the Mesozoic schists located in the hanging wall of the extensional detachments in Eocene times. It resulted in NE-SW oriented open folds representing corrugation antiforms of the extensional detachment surfaces, brittle faulting and burial history beneath thick Eocene sediments as indicated by 42.1-39.7 Ma Ar-40/Ar-39 mica plateau ages obtained in the study. The results provide structural constraints for the involvement components of Jurassic paleo-subduction zone in a Late Jurassic arc-continental margin collisional history that contributed to accretion-related crustal growth of the Rhodope terrane. (C) 2011 Elsevier Ltd. All rights reserved.

Ability for self-care and its association with sociodemographic factors of people with spinal cord injury

This study aimed to verify the association between self-care ability and sociodemographic factors of people with spinal cord injury (SCI). It was a cross-sectional study, conducted in 2012, in all 58 Basic Health Units of Natal/RN, Brazil. Seventy-three subjects completed a sociodemographic form andSelf-Care Agency Scale. Statistical analyses were performed using SPSS,including Cronbach’s Alpha, Chi-square, Fisher’s and contingency coefficient tests. The Cronbach's alpha was 0.788. The result verified that sex (p = 0.028), religion (p <0.001), education (p = 0.046), current age (p = 0.027), SCI time (p = 0.020) and the SCI type (p = 0.012) were variables associated with self-care ability of the subjects. It was concluded that sociodemographic factors may interfere with the self-care ability of persons with SCI, and nurses should consider this aspect during the execution of the nursing process.

Geographic variation in sex-chromosome differentiation in the common frog (Rana temporaria).

In sharp contrast with birds and mammals, sex-determination systems in ectothermic vertebrates are often highly dynamic and sometimes multifactorial. Both environmental and genetic effects have been documented in common frogs (Rana temporaria). One genetic linkage group, mapping to the largest pair of chromosomes and harbouring the candidate sex-determining gene Dmrt1, associates with sex in several populations throughout Europe, but association varies both within and among populations. Here, we show that sex association at this linkage group differs among populations along a 1500-km transect across Sweden. Genetic differentiation between sexes is strongest (FST  = 0.152) in a northern-boreal population, where male-specific alleles and heterozygote excesses (FIS  = -0.418 in males, +0.025 in females) testify to a male-heterogametic system and lack of X-Y recombination. In the southernmost population (nemoral climate), in contrast, sexes share the same alleles at the same frequencies (FST  = 0.007 between sexes), suggesting unrestricted recombination. Other populations show intermediate levels of sex differentiation, with males falling in two categories: some cluster with females, while others display male-specific Y haplotypes. This polymorphism may result from differences between populations in the patterns of X-Y recombination, co-option of an alternative sex-chromosome pair, or a mixed sex-determination system where maleness is controlled either by genes or by environment depending on populations or families. We propose approaches to test among these alternative models, to disentangle the effects of climate and phylogeography on the latitudinal trend, and to sort out how this polymorphism relates to the 'sexual races' described in common frogs in the 1930s.

Polymorphisms in Toll-like receptor 4 (TLR4) are associated with protection against leprosy.

Accumulating evidence suggests that polymorphisms in Toll-like receptors (TLRs) influence the pathogenesis of mycobacterial infections, including leprosy, a disease whose manifestations depend on host immune responses. Polymorphisms in TLR2 are associated with an increased risk of reversal reaction, but not susceptibility to leprosy itself. We examined whether polymorphisms in TLR4 are associated with susceptibility to leprosy in a cohort of 441 Ethiopian leprosy patients and 197 healthy controls. We found that two single nucleotide polymorphisms (SNPs) in TLR4 (896G>A [D299G] and 1196C>T [T399I]) were associated with a protective effect against the disease. The 896GG, GA and AA genotypes were found in 91.7, 7.8 and 0.5% of leprosy cases versus 79.9, 19.1 and 1.0% of controls, respectively (odds ratio [OR] = 0.34, 95% confidence interval [CI] 0.20-0.57, P < 0.001, additive model). Similarly, the 1196CC, CT and TT genotypes were found in 98.1, 1.9 and 0% of leprosy cases versus 91.8, 7.7 and 0.5% of controls, respectively (OR = 0.16, 95% CI 0.06--.40, P < 0.001, dominant model). We found that Mycobacterium leprae stimulation of monocytes partially inhibited their subsequent response to lipopolysaccharide (LPS) stimulation. Our data suggest that TLR4 polymorphisms are associated with susceptibility to leprosy and that this effect may be mediated at the cellular level by the modulation of TLR4 signalling by M. leprae.

The role of role uncertainty in modified dictator games

We compare behavior in modified dictator games with and without role uncertainty. Subjectschoose between a selfish action, a costly surplus creating action (altruistic behavior) and acostly surplus destroying action (spiteful behavior). While costly surplus creating actions are themost frequent under role uncertainty (64%), selfish actions become the most frequent withoutrole uncertainty (69%). Also, the frequency of surplus destroying choices is negligible with roleuncertainty (1%) but not so without it (11%). A classification of subjects into four differenttypes of interdependent preferences (Selfish, Social Welfare maximizing, Inequity Averse andCompetitive) shows that the use of role uncertainty overestimates the prevalence of SocialWelfare maximizing preferences in the subject population (from 74% with role uncertainty to21% without it) and underestimates Selfish and Inequity Averse preferences. An additionaltreatment, in which subjects undertake an understanding test before participating in theexperiment with role uncertainty, shows that the vast majority of subjects (93%) correctlyunderstand the payoff mechanism with role uncertainty, but yet surplus creating actions weremost frequent. Our results warn against the use of role uncertainty in experiments that aim tomeasure the prevalence of interdependent preferences.

Ratio maps and correspondence analysis

We compare two methods for visualising contingency tables and developa method called the ratio map which combines the good properties of both.The first is a biplot based on the logratio approach to compositional dataanalysis. This approach is founded on the principle of subcompositionalcoherence, which assures that results are invariant to considering subsetsof the composition. The second approach, correspondence analysis, isbased on the chi-square approach to contingency table analysis. Acornerstone of correspondence analysis is the principle of distributionalequivalence, which assures invariance in the results when rows or columnswith identical conditional proportions are merged. Both methods may bedescribed as singular value decompositions of appropriately transformedmatrices. Correspondence analysis includes a weighting of the rows andcolumns proportional to the margins of the table. If this idea of row andcolumn weights is introduced into the logratio biplot, we obtain a methodwhich obeys both principles of subcompositional coherence and distributionalequivalence.

OS CONTRACTOS DE CONCESSÃO NO CONTEXTO DO SISTEMA DE NORMALIZAÇÃO CONTABILÍSTICA E DE RELATO FINANCEIRO

A mudança do normativo contabilístico ocorrido em 2009, alterou o paradigma de reconhecimento e mensuração de activos. Embora a natureza das operações contínua presente no processo contabilístico, muitas coisas foram alteradas tendo em conta a substância da informação e a sua realidade económica. O caso dos contratos de concessão é disto um bom exemplo. Há casos em que no normativo anterior eram reconhecidos como activos fixos tangíveis e actualmente são reconhecidos como intangíveis. O estudo em causa tem como objetivo principal analisar o conceito dos contratos de concessão, bem como os procedimentos para o reconhecimento, mensuração e divulgação nas demonstrações financeiras. Considerados activos intangíveis (de facto a entidade acaba por ter um “Direito” de explorar um determinado activo), o processo contabilístico é feito a luz do disposto na Norma de Relato Financeiro nº6 – Activos Intangíveis. Os contractos de concessão apresentam especificidades próprias e por esta razão o IASB emitiu uma IFRIC (nº 12) com o objectivo de clarificar o tratamento contabilístico desta problemática. Não existindo no normativo nacional tal norma interpretativa as empresas nacionais que convivem com esta realidade vêem-se na contingência de, supletivamente, recorrer às normas internacionais de contabilidade para resolver o assunto. É o caso da ELECTRA para os activos afectos a distribuição. Neste sentido, o estudo debruça sobre esta problemática, apresenta um enquadramento teórico, analisar os principais aspectos de reconhecimento a luz dos dois normativos contabilísticos nacionais (o antigo Plano Nacional de Contabilidade e o actual Sistema de Normalização Contabilística e de Relato Financeiro) e termina utilizando as informações da ELECTRA, SARL para ilustrar este processo de reconhecimento contabilístico. The change of a the accounting regulatory occurred in 2009, changed the paradigm for recognizing and measuring assets. Although the continuous nature of the operations in this accounting process, many things have changed in view of the substance of information and its economic reality. The case of concession contracts, it is a good example. There are cases where the former were recognized as legal and tangible fixed assets are currently recognized as intangible assets. The study is aimed to analyzing the concept of concession contracts, as well as procedures for the recognition, measurement and disclosure in the financial statements. Considered intangible assets (in fact the entity turns out to have a “right” to exploit a particular asset) the accounting process is done in light of the provisions of Financial Reporting Standard No. 6 – Intangible Assets. The concession contracts have specific characteristics and for this reason the IASB issued IFRIC one (Ner. 12 ) in order to clarify the accounting treatment of this problem. In the absence of such a standard national regulatory interpretative national companies that live with this reality find themselves in contingency, additionally, make use of international accounting standards to resolve the matter. ELECTRA is the case of the assets connected to the distribution. In this sense, the study focuses on this issue, presents a theoretical framework to analyze the main aspects of recognition light of both national accounting standards (formerly the National Accounting Standards and the current system of accounting and financial reporting) and ends up using the information the Electra SARL to illustrate this process of accounting recognition.

Power transformations in correspondence analysis

Power transformations of positive data tables, prior to applying the correspondence analysis algorithm, are shown to open up a family of methods with direct connections to the analysis of log-ratios. Two variations of this idea are illustrated. The first approach is simply to power the original data and perform a correspondence analysis this method is shown to converge to unweighted log-ratio analysis as the power parameter tends to zero. The second approach is to apply the power transformation to thecontingency ratios, that is the values in the table relative to expected values based on the marginals this method converges to weighted log-ratio analysis, or the spectral map. Two applications are described: first, a matrix of population genetic data which is inherently two-dimensional, and second, a larger cross-tabulation with higher dimensionality, from a linguistic analysis of several books.

Selling to consumers with endogenous types

For many goods (such as experience goods or addictive goods), consumers preferences may change over time. In this paper, we examine a monopolist s optimal pricing schedule when current consumption can affect a consumer s valuation in the future and valuations are unobservable. We assume that consumers are anonymous, i.e. the monopolist can t observe a consumer s past consumption history. For myopic consumers, the optimal consumption schedule is distorted upwards, involving substantial discounts for low valuation types. This pushes low types into higher valuations, from which rents can be extracted.For forward looking consumers, there may be a further upward distortion of consumption due to a reversal of the adverse selection effect; low valuation consumers now have a strong interest in consumption in order to increase their valuations. Firms will find it profitable to educate consumers and encourage forward looking behavior.

Roux-en-Y gastric bypass vs gastric banding for morbid obesity: a case-matched study of 442 patients.

HYPOTHESIS: Gastric banding (GB) and Roux-en-Y gastric bypass (RYGBP) are used in the treatment of morbidly obese patients. We hypothesized that RYGBP provides superior results. DESIGN: Matched-pair study in patients with a body mass index (BMI) less than 50. SETTING: University hospital and regional community hospital with a common bariatric surgeon. PATIENTS: Four hundred forty-two patients were matched according to sex, age, and BMI. INTERVENTIONS: Laparoscopic GB or RYGBP. MAIN OUTCOME MEASURES: Operative morbidity, weight loss, residual BMI, quality of life, food tolerance, lipid profile, and long-term morbidity. RESULTS: Follow-up was 92.3% at the end of the study period (6 years postoperatively). Early morbidity was higher after RYGBP than after GB (17.2% vs 5.4%; P<.001), but major morbidity was similar. Weight loss was quicker, maximal weight loss was greater, and weight loss remained significantly better after RYGBP until the sixth postoperative year. At 6 years, there were more failures (BMI>35 or reversal of the procedure/conversion) after GB (48.3% vs 12.3%; P<.001). There were more long-term complications (41.6% vs 19%; P.001) and more reoperations (26.7% vs 12.7%; P<.001) after GB. Comorbidities improved more after RYGBP. CONCLUSIONS: Roux-en-Y gastric bypass is associated with better weight loss, resulting in a better correction of some comorbidities than GB, at the price of a higher early complication rate. This difference, however, is largely compensated by the much higher long-term complication and reoperation rates seen after GB.

Análise de Dados de Desemprego em Cabo Verde

Este trabalho baseia-se na análise de dados do desemprego em Cabo Verde nos anos de 2006 e 2008, usando informação da base de dados do INE e IEFP. Partindo da análise dos dados em estudo vai-se procurar descrever e perspectivar metodologias que contemplam as variáveis qualitativas e quantitativas com significado social positivo para a sociedade deste país. Após a introdução no capítulo 1, fez-se, no capítulo 2, a análise exploratória dos dados do desemprego em Cabo Verde referente aos anos 2006 e 2008. No capítulo 3 estudam-se associações entre variáveis, usando a metodologia de tabelas contingência, através da realização de testes de independência e testes de homogeneidade, e análise de medidas de associação. As variáveis usadas, vão ser essencialmente, o escalão etário, o género e o ano. O capítulo 4 é dedicado ao estudo de modelos Log - lineares em tabela de contingência, finalizando-se o trabalho com a apresentação das principais conclusões.

Education, growth and income inequality

Estimates of the e¤ect of education on GDP (the social return to education)have been hard to reconcile with micro evidence on the private return. We present a simple explanation that combines two ideas: imperfect substitution between worker types and endogenous skill biased technological progress. When types of workers are imperfect substitutes, the supply of human capital is negatively related to its return, and a higher education level compresses wage di¤erentials. We use cross-country panel data on income inequality to estimate the private return and GDP data to estimate the social return. The results show that the private return falls by 2 percentage points when the average education level increases by a year, which is consistent with Katz and Murphy's [1992] estimate of the elasticity of substitution between worker types. We find no evidence for dynamics in the private return, and certainly not for a reversal of the negative e¤ect as described in Acemoglu [2002]. The short run social return equals the private return.

Dynamic graphics of parametrically linked multivariate methods used in compositional data analysis

Many multivariate methods that are apparently distinct can be linked by introducing oneor more parameters in their definition. Methods that can be linked in this way arecorrespondence analysis, unweighted or weighted logratio analysis (the latter alsoknown as "spectral mapping"), nonsymmetric correspondence analysis, principalcomponent analysis (with and without logarithmic transformation of the data) andmultidimensional scaling. In this presentation I will show how several of thesemethods, which are frequently used in compositional data analysis, may be linkedthrough parametrizations such as power transformations, linear transformations andconvex linear combinations. Since the methods of interest here all lead to visual mapsof data, a "movie" can be made where where the linking parameter is allowed to vary insmall steps: the results are recalculated "frame by frame" and one can see the smoothchange from one method to another. Several of these "movies" will be shown, giving adeeper insight into the similarities and differences between these methods.