Multiple Quaternary Refugia in the Eastern Guiana Shield Revealed by Comparative Phylogeography of 12 Frog Species

The Guiana Shield (GS) is one of the most pristine regions of Amazonia and biologically one of the richest areas on Earth. How and when this massive diversity arose remains the subject of considerable debate. The prevailing hypothesis of Quaternary glacial refugia suggests that a part of the eastern GS, among other areas in Amazonia, served as stable forested refugia during periods of aridity. However, the recently proposed disturbance-vicariance hypothesis proposes that fluctuations in temperature on orbital timescales, with some associated aridity, have driven Neotropical diversification. The expectations of the temporal and spatial organization of biodiversity differ between these two hypotheses. Here, we compare the genetic structure of 12 leaf-litter inhabiting frog species from the GS lowlands using a combination of mitochondrial and nuclear sequences in an integrative analytical approach that includes phylogenetic reconstructions, molecular dating, and Geographic Information System methods. This comparative and integrated approach overcomes the well-known limitations of phylogeographic inference based on single species and single loci. All of the focal species exhibit distinct phylogeographic patterns highlighting taxon-specific historical distributions, ecological tolerances to climatic disturbance, and dispersal abilities. Nevertheless, all but one species exhibit a history of fragmentation/isolation within the eastern GS during the Quaternary with spatial and temporal concordance among species. The signature of isolation in northern French Guiana (FG) during the early Pleistocene is particularly clear. Approximate Bayesian Computation supports the synchrony of the divergence between northern FG and other GS lineages. Substructure observed throughout the GS suggests further Quaternary fragmentation and a role for rivers. Our findings support fragmentation of moist tropical forest in the eastern GS during this period when the refuge hypothesis would have the region serving as a contiguous wet-forest refuge.

Acceptance Threshold Hypothesis is Supported by Chemical Similarity of Cuticular Hydrocarbons in a Stingless Bee, Melipona asilvai

The ability to discriminate nestmates from non-nestmates in insect societies is essential to protect colonies from conspecific invaders. The acceptance threshold hypothesis predicts that organisms whose recognition systems classify recipients without errors should optimize the balance between acceptance and rejection. In this process, cuticular hydrocarbons play an important role as cues of recognition in social insects. The aims of this study were to determine whether guards exhibit a restrictive level of rejection towards chemically distinct individuals, becoming more permissive during the encounters with either nestmate or non-nestmate individuals bearing chemically similar profiles. The study demonstrates that Melipona asilvai (Hymenoptera: Apidae: Meliponini) guards exhibit a flexible system of nestmate recognition according to the degree of chemical similarity between the incoming forager and its own cuticular hydrocarbons profile. Guards became less restrictive in their acceptance rates when they encounter non-nestmates with highly similar chemical profiles, which they probably mistake for nestmates, hence broadening their acceptance level.

The CUPID (Cultural and Psychosocial Influences on Disability) Study: Methods of Data Collection and Characteristics of Study Sample

Background: The CUPID (Cultural and Psychosocial Influences on Disability) study was established to explore the hypothesis that common musculoskeletal disorders (MSDs) and associated disability are importantly influenced by culturally determined health beliefs and expectations. This paper describes the methods of data collection and various characteristics of the study sample. Methods/Principal Findings: A standardised questionnaire covering musculoskeletal symptoms, disability and potential risk factors, was used to collect information from 47 samples of nurses, office workers, and other (mostly manual) workers in 18 countries from six continents. In addition, local investigators provided data on economic aspects of employment for each occupational group. Participation exceeded 80% in 33 of the 47 occupational groups, and after pre-specified exclusions, analysis was based on 12,426 subjects (92 to 1018 per occupational group). As expected, there was high usage of computer keyboards by office workers, while nurses had the highest prevalence of heavy manual lifting in all but one country. There was substantial heterogeneity between occupational groups in economic and psychosocial aspects of work; three-to fivefold variation in awareness of someone outside work with musculoskeletal pain; and more than ten-fold variation in the prevalence of adverse health beliefs about back and arm pain, and in awareness of terms such as "repetitive strain injury" (RSI). Conclusions/Significance: The large differences in psychosocial risk factors (including knowledge and beliefs about MSDs) between occupational groups should allow the study hypothesis to be addressed effectively.

Segmental dataset and whole body expression data do not support the hypothesis that non-random movement is an intrinsic property of Drosophila retrogenes

Background: Several studies in Drosophila have shown excessive movement of retrogenes from the X chromosome to autosomes, and that these genes are frequently expressed in the testis. This phenomenon has led to several hypotheses invoking natural selection as the process driving male-biased genes to the autosomes. Metta and Schlotterer (BMC Evol Biol 2010, 10:114) analyzed a set of retrogenes where the parental gene has been subsequently lost. They assumed that this class of retrogenes replaced the ancestral functions of the parental gene, and reported that these retrogenes, although mostly originating from movement out of the X chromosome, showed female-biased or unbiased expression. These observations led the authors to suggest that selective forces (such as meiotic sex chromosome inactivation and sexual antagonism) were not responsible for the observed pattern of retrogene movement out of the X chromosome. Results: We reanalyzed the dataset published by Metta and Schlotterer and found several issues that led us to a different conclusion. In particular, Metta and Schlotterer used a dataset combined with expression data in which significant sex-biased expression is not detectable. First, the authors used a segmental dataset where the genes selected for analysis were less testis-biased in expression than those that were excluded from the study. Second, sex-biased expression was defined by comparing male and female whole-body data and not the expression of these genes in gonadal tissues. This approach significantly reduces the probability of detecting sex-biased expressed genes, which explains why the vast majority of the genes analyzed (parental and retrogenes) were equally expressed in both males and females. Third, the female-biased expression observed by Metta and Schltterer is mostly found for parental genes located on the X chromosome, which is known to be enriched with genes with female-biased expression. Fourth, using additional gonad expression data, we found that autosomal genes analyzed by Metta and Schlotterer are less up regulated in ovaries and have higher chance to be expressed in meiotic cells of spermatogenesis when compared to X-linked genes. Conclusions: The criteria used to select retrogenes and the sex-biased expression data based on whole adult flies generated a segmental dataset of female-biased and unbiased expressed genes that was unable to detect the higher propensity of autosomal retrogenes to be expressed in males. Thus, there is no support for the authors' view that the movement of new retrogenes, which originated from X-linked parental genes, was not driven by selection. Therefore, selection-based genetic models remain the most parsimonious explanations for the observed chromosomal distribution of retrogenes.

Adaptation and validation of the Patient Expectations and Satisfaction with Prenatal Care instrument among Brazilian pregnant women

Objective: to adapt and validate the Patient Expectations and Satisfaction with Prenatal Care instrument for use in Brazil. It contains 41 items divided into two dimensions: expectations and satisfaction. The adapted version was submitted to analysis for stability, convergent construct validity, and internal consistency (Cronbach’s alpha) for distinct groups and dimensions. Method: 119 pregnant women receiving prenatal care were interviewed and 26 of these women answered the instrument twice (retest). Internal consistency was appropriate (Cronbach’s alpha ≥ 0.70); test-retest presented strong correlation (r=0.82; p<0.001) for the domain expectations and moderate correlation (r=0.66; p<0.001) for the satisfaction domain. The analysis confirmed that the instrument’s adapted version is valid in the studied group. Results: there is strong evidence for the validity and reliability of the instrument’s adaptation. Conclusion: the instrument needs to be tested in groups of pregnant women with different social characteristics.

Trypanosoma livingstonei: a new species from African bats supports the bat seeding hypothesis for the Trypanosoma cruzi clade

Abstract Background Bat trypanosomes have been implicated in the evolutionary history of the T. cruzi clade, which comprises species from a wide geographic and host range in South America, Africa and Europe, including bat-restricted species and the generalist agents of human American trypanosomosis T. cruzi and T. rangeli. Methods Trypanosomes from bats (Rhinolophus landeri and Hipposideros caffer) captured in Mozambique, southeast Africa, were isolated by hemoculture. Barcoding was carried out through the V7V8 region of Small Subunit (SSU) rRNA and Fluorescent Fragment Length barcoding (FFLB). Phylogenetic inferences were based on SSU rRNA, glyceraldehyde phosphate dehydrogenase (gGAPDH) and Spliced Leader (SL) genes. Morphological characterization included light, scanning and transmission electron microscopy. Results New trypanosomes from bats clustered together forming a clade basal to a larger assemblage called the T. cruzi clade. Barcoding, phylogenetic analyses and genetic distances based on SSU rRNA and gGAPDH supported these trypanosomes as a new species, which we named Trypanosoma livingstonei n. sp. The large and highly polymorphic SL gene repeats of this species showed a copy of the 5S ribosomal RNA into the intergenic region. Unique morphological (large and broad blood trypomastigotes compatible to species of the subgenus Megatrypanum and cultures showing highly pleomorphic epimastigotes and long and slender trypomastigotes) and ultrastructural (cytostome and reservosomes) features and growth behaviour (when co-cultivated with HeLa cells at 37°C differentiated into trypomastigotes resembling the blood forms and do not invaded the cells) complemented the description of this species. Conclusion Phylogenetic inferences supported the hypothesis that Trypanosoma livingstonei n. sp. diverged from a common ancestral bat trypanosome that evolved exclusively in Chiroptera or switched at independent opportunities to mammals of several orders forming the clade T. cruzi, hence, providing further support for the bat seeding hypothesis to explain the origin of T. cruzi and T. rangeli.

Being the mother of a pregnant adolescent: experiences and expectations

OBJECTIVE: To understand the typical actions of the mother during the pregnancy of her teenage daughter. METHODS: Qualitative study, based on the theoretical-methodological framework of social phenomenology of Alfred Schütz. The data were collected in 2009, and the subjects were nine mothers of adolescent primigravidae. RESULTS: The mother of the pregnant adolescent is typified as one that reacts with surprise and disappointment to being notified of the pregnancy and who, subsequently, conforms to the new reality. In reflecting on her own experience of an adolescent mother, she has expectations to support her daughter during the pregnancy and to offer support, so that the course of her life is not impaired as a result of pregnancy. CONCLUSION: Considering the experience and expectations of the mother of the pregnant adolescent, this study could give subsidies to the planning and execution of the care for this binomial, decreasing the distance between the demands made by it and the practice of health professionals.

Trypanosoma livingstonei: a new species from African bats supports the bat seeding hypothesis for the Trypanosoma cruzi clade

BACKGROUND: Bat trypanosomes have been implicated in the evolutionary history of the T. cruzi clade, which comprises species from a wide geographic and host range in South America, Africa and Europe, including bat-restricted species and the generalist agents of human American trypanosomosis T. cruzi and T. rangeli. METHODS: Trypanosomes from bats (Rhinolophus landeri and Hipposideros caffer) captured in Mozambique, southeast Africa, were isolated by hemoculture. Barcoding was carried out through the V7V8 region of Small Subunit (SSU) rRNA and Fluorescent Fragment Length barcoding (FFLB). Phylogenetic inferences were based on SSU rRNA, glyceraldehyde phosphate dehydrogenase (gGAPDH) and Spliced Leader (SL) genes. Morphological characterization included light, scanning and transmission electron microscopy. RESULTS: New trypanosomes from bats clustered together forming a clade basal to a larger assemblage called the T. cruzi clade. Barcoding, phylogenetic analyses and genetic distances based on SSU rRNA and gGAPDH supported these trypanosomes as a new species, which we named Trypanosoma livingstonei n. sp. The large and highly polymorphic SL gene repeats of this species showed a copy of the 5S ribosomal RNA into the intergenic region. Unique morphological (large and broad blood trypomastigotes compatible to species of the subgenus Megatrypanum and cultures showing highly pleomorphic epimastigotes and long and slender trypomastigotes) and ultrastructural (cytostome and reservosomes) features and growth behaviour (when co-cultivated with HeLa cells at 37°C differentiated into trypomastigotes resembling the blood forms and do not invaded the cells) complemented the description of this species. CONCLUSION: Phylogenetic inferences supported the hypothesis that Trypanosoma livingstonei n. sp. diverged from a common ancestral bat trypanosome that evolved exclusively in Chiroptera or switched at independent opportunities to mammals of several orders forming the clade T. cruzi, hence, providing further support for the bat seeding hypothesis to explain the origin of T. cruzi and T. rangeli.

Modelli non lineari statici e dinamici su dati microeconomici: analisi delle condizioni finanziarie delle famiglie italiane

The thesis studies the economic and financial conditions of Italian households, by using microeconomic data of the Survey on Household Income and Wealth (SHIW) over the period 1998-2006. It develops along two lines of enquiry. First it studies the determinants of households holdings of assets and liabilities and estimates their correlation degree. After a review of the literature, it estimates two non-linear multivariate models on the interactions between assets and liabilities with repeated cross-sections. Second, it analyses households financial difficulties. It defines a quantitative measure of financial distress and tests, by means of non-linear dynamic probit models, whether the probability of experiencing financial difficulties is persistent over time. Chapter 1 provides a critical review of the theoretical and empirical literature on the estimation of assets and liabilities holdings, on their interactions and on households net wealth. The review stresses the fact that a large part of the literature explain households debt holdings as a function, among others, of net wealth, an assumption that runs into possible endogeneity problems. Chapter 2 defines two non-linear multivariate models to study the interactions between assets and liabilities held by Italian households. Estimation refers to a pooling of cross-sections of SHIW. The first model is a bivariate tobit that estimates factors affecting assets and liabilities and their degree of correlation with results coherent with theoretical expectations. To tackle the presence of non normality and heteroskedasticity in the error term, generating non consistent tobit estimators, semi-parametric estimates are provided that confirm the results of the tobit model. The second model is a quadrivariate probit on three different assets (safe, risky and real) and total liabilities; the results show the expected patterns of interdependence suggested by theoretical considerations. Chapter 3 reviews the methodologies for estimating non-linear dynamic panel data models, drawing attention to the problems to be dealt with to obtain consistent estimators. Specific attention is given to the initial condition problem raised by the inclusion of the lagged dependent variable in the set of explanatory variables. The advantage of using dynamic panel data models lies in the fact that they allow to simultaneously account for true state dependence, via the lagged variable, and unobserved heterogeneity via individual effects specification. Chapter 4 applies the models reviewed in Chapter 3 to analyse financial difficulties of Italian households, by using information on net wealth as provided in the panel component of the SHIW. The aim is to test whether households persistently experience financial difficulties over time. A thorough discussion is provided of the alternative approaches proposed by the literature (subjective/qualitative indicators versus quantitative indexes) to identify households in financial distress. Households in financial difficulties are identified as those holding amounts of net wealth lower than the value corresponding to the first quartile of net wealth distribution. Estimation is conducted via four different methods: the pooled probit model, the random effects probit model with exogenous initial conditions, the Heckman model and the recently developed Wooldridge model. Results obtained from all estimators accept the null hypothesis of true state dependence and show that, according with the literature, less sophisticated models, namely the pooled and exogenous models, over-estimate such persistence.

The genetic signature of Neolithic in Greece

The Neolithic is characterized by the transition from a subsistence economy, based on hunting and gathering, to one based on food producing. This important change was paralleled by one of the most significant demographic increase in the recent history of European populations. The earliest Neolithic sites in Europe are located in Greece. However, the debate regarding the colonization route followed by the Middle-eastern farmers is still open. Based on archaeological, archaeobotanical, craniometric and genetic data, two main hypotheses have been proposed. The first implies the maritime colonization of North-eastern Peloponnesus from Crete, whereas the second points to an island hopping route that finally brought migrants to Central Greece. To test these hypotheses using a genetic approach, 206 samples were collected from the two Greek regions proposed as the arrival point of the two routes (Korinthian district and Euboea). Expectations for each hypothesis were compared with empirical observations based on the analysis of 60 SNPs and 26 microsatellite loci of Y-chromosome and mitochondrial DNA hypervariable region I. The analysis of Y-chromosome haplogroups revealed a strong genetic affinity of Euboea with Anatolian and Middle-eastern populations. The inferences of the time since population expansion suggests an earlier usage of agriculture in Euboea. Moreover, the haplogroup J2a-M410, supposed to be associated with the Neolithic transition, was observed at higher frequency and variance in Euboea showing, for both these parameters, a decreasing gradient moving from this area. The time since expansion estimates for J2a-M410 was found to be compatible with the Neolithic and slightly older in Euboea. The analysis of mtDNA resulted less informative. However, a higher genetic affinity of Euboea with Anatolian and Middle-eastern populations was confirmed. These results taken as a whole suggests that the most probable route followed by Neolithic farmers during the colonization of Greece was the island hopping route.

Il principio di continuità nel diritto amministrativo

Il presente lavoro si propone principalmente di fornire un’analisi delle declinazioni assunte dal principio di continuità nel diritto amministrativo, tentando di metterne in luce al contempo le basi fondanti che caratterizzano ogni principio generale e le sfumature più attuali emerse dall’elaborazione della dottrina e della giurisprudenza più recenti. Partendo dal fondamentale presupposto secondo cui la maggior parte degli interpreti si è interessata al principio di continuità in campo amministrativo con prevalente riferimento all’ambito organizzativo-strutturale, si è tentato di estendere l’analisi sino a riconoscervi una manifestazione di principi chiave della funzione amministrativa complessivamente intesa quali efficienza, buon andamento, realizzazione di buoni risultati. La rilevanza centrale della continuità discende dalla sua infinita declinabilità, ma in questo lavoro si insiste particolarmente sul fatto che di essa possono darsi due fondamentali interpretazioni, tra loro fortemente connesse, che si influenzano reciprocamente: a quella che la intende come segno di stabilità perenne, capace di assicurare certezza sul modus operandi delle pubbliche amministrazioni e tutela degli affidamenti da esse ingenerati, si affianca una seconda visione che ne privilegia invece l’aspetto dinamico, interpretandola come il criterio che impone alla P.A. di assecondare la realtà che muta, evolvendo contestualmente ad essa, al fine di assicurare la permanenza del risultato utile per la collettività, in ossequio alla sua missione di cura. In questa prospettiva, il presente lavoro si propone di analizzare, nella sua prima parte, i risultati già raggiunti dall’elaborazione esegetica in materia di continuità amministrativa, con particolare riferimento alle sue manifestazioni nel campo dell’organizzazione e dell’attività amministrative, nonché ad alcune sue espressioni concrete nel settore degli appalti e dei servizi pubblici. La seconda parte è invece dedicata a fornire alcuni spunti ed ipotesi per nuove interpretazioni del principio in chiave sistematica, in relazione a concetti generali quali il tempo, lo spazio e il complessivo disegno progettuale della funzione amministrativa.

A threshold hypothesis of institutional change: collective action in the Italian Alps during the 13th - 19th centuries.

This dissertation is about collective action issues in common property resources. Its focus is the “threshold hypothesis,” which posits the existence of a threshold in group size that drives the process of institutional change. This hypothesis is tested using a six-century dataset concerning the management of the commons by hundreds of communities in the Italian Alps. The analysis seeks to determine the group size threshold and the institutional changes that occur when groups cross this threshold. There are five main findings. First, the number of individuals in villages remained stable for six centuries, despite the population in the region tripling in the same period. Second, the longitudinal analysis of face-to-face assemblies and community size led to the empirical identification of a threshold size that triggered the transition from informal to more formal regimes to manage common property resources. Third, when groups increased in size, gradual organizational changes took place: large groups split into independent subgroups or structured interactions into multiple layers while maintaining a single formal organization. Fourth, resource heterogeneity seemed to have had no significant impact on various institutional characteristics. Fifth, social heterogeneity showed statistically significant impacts, especially on institutional complexity, consensus, and the relative importance of governance rules versus resource management rules. Overall, the empirical evidence from this research supports the “threshold hypothesis.” These findings shed light on the rationale of institutional change in common property regimes, and clarify the mechanisms of collective action in traditional societies. Further research may generalize these conclusions to other domains of collective action and to present-day applications.

Production of Z bosons in proton-proton collisions at root out s = 10 TeV: Expectations for early measurements at the ATLAS experiment

The production of the Z boson in proton-proton collisions at the LHC serves as a standard candle at the ATLAS experiment during early data-taking. The decay of the Z into an electron-positron pair gives a clean signature in the detector that allows for calibration and performance studies. The cross-section of ~ 1 nb allows first LHC measurements of parton density functions. In this thesis, simulations of 10 TeV collisions at the ATLAS detector are studied. The challenges for an experimental measurement of the cross-section with an integrated luminositiy of 100 pb−1 are discussed. In preparation for the cross-section determination, the single-electron efficiencies are determined via a simulation based method and in a test of a data-driven ansatz. The two methods show a very good agreement and differ by ~ 3% at most. The ingredients of an inclusive and a differential Z production cross-section measurement at ATLAS are discussed and their possible contributions to systematic uncertainties are presented. For a combined sample of signal and background the expected uncertainty on the inclusive cross-section for an integrated luminosity of 100 pb−1 is determined to 1.5% (stat) +/- 4.2% (syst) +/- 10% (lumi). The possibilities for single-differential cross-section measurements in rapidity and transverse momentum of the Z boson, which are important quantities because of the impact on parton density functions and the capability to check for non-pertubative effects in pQCD, are outlined. The issues of an efficiency correction based on electron efficiencies as function of the electron’s transverse momentum and pseudorapidity are studied. A possible alternative is demonstrated by expanding the two-dimensional efficiencies with the additional dimension of the invariant mass of the two leptons of the Z decay.

Estimation of Quasi-Rational DSGE Models

Small-scale dynamic stochastic general equilibrium have been treated as the benchmark of much of the monetary policy literature, given their ability to explain the impact of monetary policy on output, inflation and financial markets. One cause of the empirical failure of New Keynesian models is partially due to the Rational Expectations (RE) paradigm, which entails a tight structure on the dynamics of the system. Under this hypothesis, the agents are assumed to know the data genereting process. In this paper, we propose the econometric analysis of New Keynesian DSGE models under an alternative expectations generating paradigm, which can be regarded as an intermediate position between rational expectations and learning, nameley an adapted version of the "Quasi-Rational" Expectatations (QRE) hypothesis. Given the agents' statistical model, we build a pseudo-structural form from the baseline system of Euler equations, imposing that the length of the reduced form is the same as in the `best' statistical model.