Genes, environment and sex : perspectives from ectothermic vertebrates

RESUMELes modèles classiques sur l'évolution des chromosomes sexuels supposent que des gènes sexe- antagonistes s'accumulent sur les chromosomes sexuels, entraînant ainsi l'apparition d'une région non- recombinante, qui se répand progressivement en favorisant l'accumulation de mutations délétères. En accord avec cette théorie, les chromosomes sexuels que l'on observe aujourd'hui chez les mammifères et les oiseaux sont considérablement différenciés. En revanche, chez la plupart des vertébrés ectothermes, les chromosomes sexuels sont indifférenciés et il existe une impressionnante diversité de mécanismes de détermination du sexe. Au cours de cette thèse, j'ai étudié l'évolution des chromosomes sexuels chez les vertébrés ectothermes, en outre pour mieux comprendre ce contraste avec les vertébrés endothermes. L'hypothèse « high-turnover » postule que les chromosomes sexuels sont remplacés régulièrement à partir d'autosomes afin d'éviter leur dégénérescence. L'hypothèse « fountain-of-youth » propose que la recombinaison entre le chromosome X et le chromosome Y au sein de femelles XY empêche la dégénérescence. Les résultats de ma thèse, basés sur des études théoriques et empiriques, suggèrent que les deux processus peuvent être entraînés par l'environnement et ainsi jouent un rôle important dans l'évolution des chromosomes sexuels chez les vertébrés ectothermes.SUMMARYClassical models of sex-chromosome evolution assume that sexually antagonistic genes accumulate on sex chromosomes leading to a non-recombining region, which progressively expands and favors the accumulation of deleterious mutations. Concordant with this theory, sex chromosomes in extant mammals and birds are considerably differentiated. In most ectothermic vertebrates, such as frogs, however, sex chromosomes are undifferentiated and a striking diversity of sex determination systems is observed. This thesis was aimed to investigate this apparent contrast of sex chromosome evolution between endothermic and ectothermic vertebrates. The "high-turnover" hypothesis holds that sex chromosomes arose regularly from autosomes preventing decay. The "fountain-of-youth" hypothesis posits that sex chromosomes undergo episodic X-Y recombination in sex-reversed XY females, thereby purging ("rejuvenating") the Y chromosome. We suggest that both processes likely played an important role in sex chromosome evolution of ectothermic vertebrates. The literature largely views sex determination as a dichotomous process: individual sex is assumed to be determined either by genetic (genotypic sex determination, GSD) or by environmental factors (environmental sex determination, ESD), most often temperature (temperature sex determination, TSD). We endorsed an alternative view, which sees GSD and TSD as the ends of a continuum. The conservatism of molecular processes among different systems of sex determination strongly supports the continuum view. We proposed to define sex as a threshold trait underlain by a liability factor, and reaction norms allowing modeling interactions between genotypic and temperature effects. We showed that temperature changes (due to e.g., climatic changes or range expansions) are expected to provoke turnovers in sex-determination mechanisms maintaining homomorphic sex chromosomes. The balanced lethal system of crested newts might be the result of such a sex determination turnover, originating from two variants of ancient Y-chromosomes. Observations from a group of tree frogs, on the other hand, supported the 'fountain of youth' hypothesis. We then showed that low rates of sex- reversals in species with GSD might actually be adaptive considering joint effects of deleterious mutation purging and sexually antagonistic selection. Ongoing climatic changes are expected to threaten species with TSD by biasing population sex ratios. In contrast, species with GSD are implicitly assumed immune against such changes, because genetic systems are thought to necessarily produce even sex ratios. We showed that this assumption may be wrong and that sex-ratio biases by climatic changes may represent a previously unrecognized extinction threat for some GSD species.

Iowa Highway Research Board Research and Development Activities FY 2015

This report, entitled Iowa Highway Research and Development Activities FY 2015, is submitted in compliance with Iowa Code section 310.36 and 312.3A, which direct the submission of a report of the Secondary Road Research Fund and the Street Research Fund, respectively. It is a report of the status of research and development projects in process on June 30, 2015. It is also a report on projects completed during the fiscal year beginning July 1, 2014 and ending June 30, 2015. Detailed information on each of the research and development projects mentioned in this report is available from the office of Research and Analytics, Performance and Technology Division, Iowa Department of Transportation. All approved reports are also online for viewing at http://www.iowadot.gov/research/pdf/IHRBAnnualReport.pdf.

Microclimate and development of 'Conilon' coffee intercropped with rubber trees

The objective of this work was to evaluate the influence of intercropping 'Conilon' coffee (Coffea canephora) with rubber trees on coffee tree microclimate, nutrition, growth, and yield. Rubber trees were planted in two double rows 33 m apart, with 4x2.3 m spacing between plants. Treatments consisted of the distances from the coffee plants to the rubber trees: 3, 6, 9, 12, and 15 m. Measurements of atmospheric variables (temperature, irradiance, and relative humidity), leaf nutrient concentration, internode length of plagiotropic and orthotropic branches, individual leaf area, chlorophyll content, and yield were performed. Intercropping promotes changes in the microclimatic conditions of coffee plants close to rubber trees, with reduction of temperature and irradiance level and increase in air relative humidity. The proximity of the coffee tree to the rubber trees promotes the elongation of the plagiotropic and orthotropic branches and increases the individual leaf area; however, it does not affect leaf concentrations of N, K, Mg, Fe, Zn, and B in 'Conilon' coffee and does not have a negative impact on yield.

The structure and development of Russia's food retail sector from the point of view of Finnish food industry

Tämän diplomityön tavoitteena on selvittää Venäjän ruoan vähittäiskaupan rakenne ja sen tuleva kehitys. Tällä hetkellä se on yksi maailman nopeimmin kasvavista markkinoista. Kasvun syynä on korkea öljyn hinta, jokaon kumuloitunut ihmisten palkkoihin. Kuitenkin vaikka tulot kasvavat, ruokaan käytetty osuus tuloista on pysynyt suhteellisen vakaana. Kulutus on siis siirtymässä laadukkaampiin ja arvokkaampiin tuotteisiin Modernien kauppojen osuus markkinoista on vielä pieni, koska Venäjän vähittäiskauppasektori on yhä hajaantunut perinteisiin kauppaformaatteihin kuten kioskeihin, toreille ja pieniin ruokakauppoihin. Kauppaketjut ovat kuitenkin tulossa merkittävämmiksi. Suurin markkina-alue vähittäiskauppiaille on Moskova, mutta tällä hetkellä ketjut laajentavat toimintojaan nopeasti myös muille Venäjän alueille. Parhaat kasvunäkymät ovat alueilla, vaikka Moskovan markkinat eivät olekaan kyllästyneet. Tärkein kasvua rajoittava tekijä Moskovassa on rakennustonttien ja kiinteistöjen saatavuus. Vähittäiskauppamarkkinat lähestyvät kyllästymispistettä, josta seuraa markkinoiden konsolidaatio. Tämä prosessi on jo alkanut, mutta kovin paljon yritysostoja ei ole vielätehty. Toistaiseksi kauppaketjut ovat tyytyneet muodostamaan alliansseja. Ketjut pyrkivät parantamaan asemaansa hintaneuvotteluissa muodostamalla osto-alliansseja, luomalla omia brändejä ja käyttämällä alueellista laajentumista lyömäaseena. Jotta ruoan tuottaja pääsisi myös alueellisille markkinoille, on sen ehkä suostuttava myymään tuotteitaan edullisempaan hintaan. Tavarantoimittajat ovat vahvassa asemassa silloin, kun heillä on toimiva jakeluverkko, kyky JIT-toimituksiin,kunnollinen dokumentaatiokäytäntö, vahva brändi ja edullinen hinta. Ns. listausmaksun suuruus voi määrittää tuottajan tuotteilleen saaman hyllytilan koon.

Germination and development of pecan cultivar seedlings by seed stratification

Abstract: The objective of this work was to evaluate the effect of seed stratification on germination rate, germination speed, and initial development of seedlings of six pecan (Carya illinoinensis) cultivars under subtropical climatic conditions in southern Brazil. For stratification, the seeds were placed in boxes with moist sand, in a cold chamber at 4°C, for 90 days. In the fourteenth week after sowing, the emergence speed index, total emergence, plant height, stem diameter, and number of leaves were evaluated. Seed stratification significantly improves the germination potential and morphological traits of the evaluated cultivars.

Research and development, where people are exposed to nanomaterials

OBJECTIVES: Many nanomaterials (materials with structures smaller than 100 nm) have chemical, physical and bioactive characteristics of interest for novel applications. Considerable research efforts have been launched in this field. This study aimed to study exposure scenarios commonly encountered in research settings. METHODS: We studied one of the leading Swiss universities and first identified all research units dealing with nanomaterials. After a preliminary evaluation of quantities and process types used, a detailed analysis was conducted in units where more than a few micrograms were used per week. RESULTS: In the investigated laboratories, background levels were usually low and in the range of a few thousand particles per cubic centimeter. Powder applications resulted in concentrations of 10,000 to 100,000 particles/cm(3) when measured inside fume hoods, but there were no or mostly minimal increases in the breathing zone of researchers. Mostly low exposures were observed for activities involving liquid applications. However, centrifugation and lyophilization of nanoparticle-containing solutions resulted in high particle number levels (up to 300,000 particles/cm(3)) in work spaces where researchers did not always wear respiratory protection. No significant increases were found for processes involving nanoparticles bound to surfaces, nor were they found in laboratories that were visualizing properties and structure of small amounts of nanomaterials. CONCLUSIONS: Research activities in modern laboratories equipped with control techniques were associated with minimal releases of nanomaterials into the working space. However, the focus should not only be on processes involving nanopowders but should also be on processes involving nanoparticle-containing liquids, especially if the work involves physical agitation, aerosolization or drying of the liquids.

Advances in research and development of mango industry

World mango production is spread over 100 countries that produce over 34.3 million tons of fruit annually. Eighty percent of this production is based in the top nine producing nations that also consume upward of 90% of their production domestically. One to 2 percent of fruit is traded internationally in to markets in the European Community, USA, Arabian Peninsula and Asia. This paper outlines some of the recent research and development advances in mango breeding and genomics, rootstock development, disease management and harvest technologies that are influencing the production and quality of mango fruit traded domestically and internationally.

Wireless Applications Evaluation and Development Process: Case -Paper Industry Logistics

Sähköisen liiketoiminnan ja mobiliteetin konvergenssi yhdessä teknologisen innovaation kiihtyvän vauhdin kanssa ovat saaneet aikaan kiinnostusta langattomia liiketoimintaratkaisuja kohtaan. Tämän diplomityön tavoitteena oli tutkia sähköisen liiketoiminnan langattomien sovellusten arviointi- ja kehitysprosessia. Työ keskittyy tarkastelemaan paperiteollisuuden toimitusketjun langatonta seurantaa. Tutkimuksessa esitetään langattoman sähköisen liiketoiminnan määritelmä, kuvaillaan langattomuuden eri sovellusalueita ja sovellusten arviointi- ja kehitysprosessin strategisia sekä teknologisia ulottuvuuksia. Työ luo viitekehyksen, jonka avulla tarkastella langattomien teknologioiden merkitystä logistiikassa. Tutkimuksen merkittävin tulos on prosessimalli sovellusten arvioimiseksi ja kehittämiseksi. Mallilla kehitetty langaton sovellus osoittautui tarkastelussa hyödylliseksi toimitusketjun hallinnassa.

Sähkösuunnittelun projektityön hallinta ja kehittäminen - Management and development of project work in electrical

Työssä on tutkittu sähkösuunnittelun projektityön hallintaa ja kehittämistä. Tavoitteena oli löytää ongelmia ja pyrkiä korjaamaan niitä, jotta suunnittelu olisi mahdollisimman toimivaa. Tutkimus perustuu kirjallisuuteen ja haastatteluihin. Työssä perehdytään kirjallisuuden avulla projektin peruskäsitteisiin ja hallintaan sekä sähkösuunnittelun projektin yleiseen toteutukseen. Haastattelujen avulla on selvitetty tämän hetkistä tilannetta sähkösuunnitteluprojektin hallinnasta ja siihen liittyvistä ongelmista Pöyryn Kouvolan konttorissa. Työn tuloksena on selvitetty merkittävimpiä ongelmia, jotka esiintyvät sähkösuunnitteluprojektissa. Työ keskittyy pääosin sähkösuunnitteluprojektin hallinnallisiin ongelmiin ja niiden toteutukseen. Kirjallisuuden ja haastattelujen pohjalta on koottu ohjeita sähkösuunnittelun projektinhallintaan

The farthest need the best. Human capital composition and development-specific economic growth

We provide robust and compelling evidence of the marked impact of tertiary education on the economic growth of less developed countries and of its the relatively smaller impact on the growth of developed ones. Our results argue in favor of the accumulation of high skill levels especially in technologically under-developed countries and, contrary to common wisdom, independently of the fact that these economies might initially produce lower-technology goods or perform technology imitation. Our results are robust to the different measures used in proxying human capital and to the adjustments made for cross-country differences in the quality of education. Country-specific institutional quality, as well as other indicators including legal origin, religious fractionalization and openness to trade have been used to control for the robustness of the results. These factors are also shown to speed up technology convergence thereby confirming previous empirical studies. Our estimates tackle problems of endogeneity by adopting a variety of techniques, including instrumental variables -for both panel and cross-section analyses- and the two-step efficient dynamics system GMM.

Plant polyamines in stress and development: an emerging area of research in plant sciences.

Compelling evidence indicates the participation of polyamines in abiotic and biotic stress responses in plants. Indeed, genetic engineering of polyamine levels in plants has successfully improved biotic and abiotic stress resistance in model plants and crops. We anticipate that many of the current challenges in agriculture to cope with climate change and maintain nutritional quality of fruits and vegetables can be approached by considering the polyamine pathway...

An integrated model of adoption and development of e-commerce in companies

Since the mid-1990s researchers have sought to understand why some firms embark on e-commerceoperations on the Internet while others prefer to wait and see how events unfold. We still have todetermine which variables contribute to explaining the extent to which firms use e-commerce, giventhat to date the literature has not yet offered conclusive evidence on this question. The current workaims to provide an integrated vision of the set of factors influencing the e-commerce adoptionprocess. We use a sample of 2,038 firms of all types that trade their products either with otherorganizations or with end-consumers.

Emergence and development of a financial cluster: the evolution of Andorra’s banking deposits in the long-term, 1931-2007

This paper explores the origins of Andorra’s financial cluster. It shows that the free movement of currency, the protection of infant industry, and geographical concentration lie at the foundation of the cluster’s competitive advantage. Drawing on a new set of data, the paper also provides for the first time an estimate of the total deposits held by Andorra’s banks between 1931 and 2007. Based on this new information, the paper reaches the conclusion that the development of the cluster went through four distinct phases in which large companies, acting as leaders, played an important role in enhancing the cluster’s business capabilities.